Dysregulated healing responses in diabetic wounds occur in the early stages postinjury.
Journal of molecular endocrinology
Chronic wounds are a serious and debilitating complication of diabetes. A better understanding of the dysregulated healing responses following injury will provide insight into the optimal time frame for therapeutic intervention. In this study, a direct comparison was done between the healing dynamics and the proteome of acute and obese diabetic wounds on days 2 and 7 following injury. Full thickness excisional wounds were induced on obese diabetic (B6.Cg-lepob/J, ob/ob, n = 14) (blood glucose 423.25 ± 127.92 mg/dL) and WT control (C57BL/6J, n = 14) (blood glucose 186.67 ± 24.5 mg/dL) mice. Histological analysis showed no signs of healing in obese DM wounds whereas complete wound closure/re-epithelisation, the formation of granulation tissue and signs of re-vascularisation, was evident in acute wounds on day 7. In obese DM wounds, substance P deficiency and increased MMP-9 activity on day 2 coincided with increased cytokine/chemokine levels within wound fluid. LC-MS/MS identified 906 proteins, of which 23 (Actn3, Itga6, Epb41, Sncg, Nefm, Rsp18, Rsp19, Rpl22, Macroh2a1, Rpn1, Ppib, Snrnp70, Ddx5, Eif3g, Tpt1, FABP5, Cavin1, Stfa1, Stfa3, Cycs, Tkt, Mb, Chmp2a) were differentially expressed in wounded tissue on day 2 (P < 0.05; more than two-fold) and 6 (Cfd, Ptms, Hp, Hmga1, Cbx3, Syap1) (P < 0.05; more than two-fold) on day 7. A large number of dysregulated proteins on day 2 was associated with an inability to progress into the proliferative stage of healing and suggest that early intervention might be pivotal for effective healing outcomes. The proteomic approach highlighted the complexity of obese DM wounds in which the dysregulation involves multiple regulatory pathways and biological processes.
10.1530/JME-20-0256
[Effects of Huanglian ointment on wound healing of mice with full-thickness skin defect and the related mechanism].
Zhang X F,Sun G F,Chen Y F,Ma J Y,Gao C F,Sheng X,Feng D X
Zhonghua shao shang za zhi = Zhonghua shaoshang zazhi = Chinese journal of burns
To observe the effects of Huanglian ointment on wound healing of mice with full-thickness skin defect, and to explore the related mechanism. Thirty male C57BL/6J mice were divided into Huanglian ointment group and vehicle group according to the random number table after round wounds of full-thickness skin defect with diameter of 7.5 mm were inflicted on the back of each mouse, with 15 mice in each group. Wounds of mice in Huanglian ointment group and vehicle group were treated with Huanglian ointment and vehicle respectively from post injury day (PID) 1 on, 2 times each day. Five mice from each group were selected to observe wound changes on PID 0, 3, 7, 10, and 14, and wound healing rates were calculated. Five mice out of the 10 mice that hadn't been used for general observation in each group were sacrificed on PID 3 and 7 respectively, and 5 mice after being used for general observation in each group were sacrificed on PID 14. Wound and skin tissue within 2 mm from the edge of wound was collected. Histologic scoring was conducted based on the histomorphological observation with HE staining. The expression of double positive cells of alpha smooth muscle actin (α-SMA) and Ki-67 (myofibroblast) in tissue of wounds of mice was observed by immunofluorescence staining. Protein expressions of transforming growth factor beta (TGF-β) and collagen in tissue of wounds of mice were determined by enzyme-linked immunosorbent assay. Data were processed with analysis of variance for repeated measurement, analysis of variance of factorial design, test of two independent samples, one-way analysis of variance, and Bonferronni test or correction. (1) Wounds of mice in two groups were red and swollen on PID 0, while they were neither red nor swollen with scabs on PID 3 and 7. On PID 10, woundsof mice in Huanglian ointment group contracted obviously, while the contracted wounds of mice in vehicle group were smaller than those in Huanglian ointment group. On PID 14, wounds of most mice in Huanglian ointment group were healed, while wounds of some mice in vehicle group failed to heal. Wound healing rates of mice in two groups were close on PID 3 and 7 (with values respectively 0.64 and 1.90, values above 0.05). Wound healing rates of mice in Huanglian ointment group on PID 10 and 14 were (76±7)% and (93±5)% respectively, significantly higher than those of vehicle group [(48±9)% and (68±11)%, with values respectively 7.44 and 3.89, values below 0.01]. Wound healing rates of mice in two groups on PID 7, 10, and 14 were significantly higher than those on the previous time points of the same group (with values below 0.01). (2) Histologic scores of wounds of mice in two groups were close on PID 3 (=-0.76, >0.05). Histologic scores of wounds of mice in Huanglian ointment group on PID 7 and 14 were (7.0±1.6) and (11.6±2.1) points respectively, significantly higher than those of vehicle group [(4.2±1.3) and (7.2±1.3) points, with values respectively 1.96 and 2.50, <0.05 or <0.01]. Histologic scores of wounds of mice in two groups on PID 7 and 14 were significantly higher than those on the previous time points of the same group (with values below 0.01). (3) Percentages of double positive cells of α-SMA and Ki-67 in tissue of wounds of mice in Huanglian ointment group on PID 3 and 7 were (35±12)% and (62±10)% respectively, significantly higher than those of vehicle group [(17±12)% and (34±6)%, with values respectively -2.48 and -5.25, <0.05 or <0.01]. The percentage of double positive cells of α-SMA and Ki-67 in tissue of wounds of mice in Huanglian ointment group on PID 14 was (25±5)%, significantly lower than that of vehicle group [(44±17)%, =2.50, <0.05]. The percentage of double positive cells of α-SMA and Ki-67 in tissue of wounds of mice on PID 7 was significantly higher than that on PID 3 or 14 in Huanglian ointment group (with values below 0.01). Percentages of double positive cells of α-SMA and Ki-67 in tissue of wounds of mice on PID 7 and 14 were significantly higher than those on the previous time points in vehicle group (with values below 0.05). (4) Protein expressions of TGF-β in tissue of wounds of mice in Huanglian ointment group on PID 3 and 7 were (396±45) and (722±96) pg/mL respectively, significantly higher than those of vehicle group [(290±42) and (382±62) pg/mL, with values respectively -8.17 and -6.65, values below 0.01]. Protein expressions of TGF-β in tissue of wounds of mice in two groups were close on PID 14 (=1.60, >0.05). The protein expression of TGF-β in tissue of wounds of mice in Huanglian ointment group on PID 7 was significantly higher than that on PID 3 or 14 (with values below 0.01). Protein expressions of TGF-β in tissue of wounds of mice in vehicle group on PID 7 and 14 were significantly higher than those on the previous time points (with values below 0.05). Protein expressions of collagen in tissue of wounds of mice in two groups were close on PID 3 (=1.99, >0.05). Protein expressions of collagen in tissue of wounds of mice in Huanglian ointment on PID 7 and 14 were (47±10) and (70±14) ng/mL respectively, significantly higher than those of vehicle group [(34±10) and (42±12) ng/mL, with values respectively 3.15 and 3.52, <0.05 or <0.01]. Protein expressions of collagen in tissue of wounds of mice in two groups on PID 7 and 14 were significantly higher than those on the previous time points of the same group (<0.05 or <0.01). Huanglian ointment can promote wound healing of full-thickness skin defect of mice through increasing production of myofibroblasts and protein expressions of TGF-β and collagen.
10.3760/cma.j.issn.1009-2587.2016.12.003
High-voltage pulsed current stimulation enhances wound healing in diabetic rats by restoring the expression of collagen, α-smooth muscle actin, and TGF-β1.
Kim Tae Hoon,Cho Hwi-Young,Lee Suk Min
The Tohoku journal of experimental medicine
Impaired wound healing is a common complication of diabetes mellitus and a major morbidity that leads to pain and severely diminished quality of life. Diabetic wounds are commonly associated with defective immune cell responses or abnormality of extracellular matrix. Various types of electrical stimulation interventions have been used to promote tissue healing. However, it is unclear whether high-voltage pulsed current stimulation (HVPCS) enhances diabetic wound healing. In this study, the effects of HVPCS on wound healing were investigated in diabetic rats. Three groups of rats (10 per group) were used: non-diabetic control, diabetic control, and diabetic rats that were administered HVPCS for 40 minutes daily for 1 week. Rats from control groups were administered sham interventions. Dorsal incision wounds were generated in all animals, and wound-healing rate was determined during one-week intervention. After interventions, we measured the relative expression levels of collagen type I (collagen-I), α-smooth muscle actin (α-SMA), and transforming growth factor-β1 (TGF-β1) mRNAs in the wounded skin. Wound closure was delayed in diabetic control rats compared to the non-diabetic control rats, and the diabetic control rats showed the reduced expression levels of collagen-I, α-SMA and TGF-β1 mRNAs. Importantly, compared to diabetic control rats, rats with HVPCS showed accelerated wound closure and healing (p < 0.01) and restored expression levels of collagen-I (p = 0.02), α-SMA (p = 0.04), and TGF-β1 (p = 0.01) mRNAs. In conclusion, HVPCS may be beneficial for enhancing the healing of diabetic wounds by restoring the expression levels of TGF-β1, collagen-I, and α-SMA.
[Effect of botulinum toxin type A on the expression of substance P, calcitonin gene-related peptide, transforming growth factor beta-1 and alpha smooth muscle actin A in wound healing in rats].
Wang Lin,Tai Ning-zheng,Fan Zhi-hong
Zhonghua zheng xing wai ke za zhi = Zhonghua zhengxing waike zazhi = Chinese journal of plastic surgery
OBJECTIVE:To investigate the effect of botulinum toxin type A on the expression of substance P (SP), calcitonin gene-related peptide (CGRP), transforming growth factor beta-1 (TGF-beta1) and alpha smooth muscle actin A (alpha-SMA) in wound healing. METHODS:60 rats were randomly divided into group C (control) group L (low-dose) and group H (high-dose), with 20 rats in each group. The wound-healing model was established by excision of four full-thickness skin (1 cm x 1 cm, around the injection site) on the back of all SD rats on the 7th day after BTA injection. The wound size was measured and the expression of SP, CGRP, TGF-beta1 and alpha-SMA in wound granulation tissue was assayed by immunohistochemical staining and computerized image analysis before operation, and 3 days, 7 days and 14 days after operation. RESULTS:All the wounds healed 14 days after operation. The wound size in L and H group was not significantly different with that in C group on the 3rd day and 7th day after operation. The positive immuno-staining of SP, CGRP, TGF-beta1 and alpha-SMA in group L and H was significantly weaker than those in C group. Meanwhile, the positive immuno-staining of all above substances in H group was weaker than those in L group significantly. CONCLUSIONS:Botulinum toxin type A can decrease the expression of SP, CGRP, TGF-beta1, and alpha-SMA in wound healing in a dose-dependent manner with no effect on the healing time.
Negative pressure wound therapy-associated tissue trauma and pain: a controlled in vivo study comparing foam and gauze dressing removal by immunohistochemistry for substance P and calcitonin gene-related peptide in the wound edge.
Malmsjö Malin,Gustafsson Lotta,Lindstedt Sandra,Ingemansson Richard
Ostomy/wound management
Pain upon negative pressure wound therapy (NPWT) dressing removal has been reported and is believed to be associated with the observation that granulation tissue grows into foam. Wound tissue damage upon removal of the foam may cause the reported pain. Calcitonin gene-related peptide (CGRP) and substance P are neuropeptides that cause inflammation and signal pain and are known to be released when tissue trauma occurs. The aim of this controlled in vivo study was to compare the expression of CGRP and substance P in the wound bed in control wounds and following NPWT and foam or gauze dressing removal. Eight pigs with two wounds each were treated with open-pore structure polyurethane foam or AMD gauze and NPWT of 0 (control) or -80 mm Hg for 72 hours. Following removal of the wound filler, the expression of CGRP and substance P was measured, using arbitrary units, in sections of biopsies from the wound bed using immunofluorescence techniques. Substance P and CGRP were more abundant in the wound edge following the removal of foam than of gauze dressings and least abundant in control wounds. The immunofluorescence staining of the wound edge for CGRP was 52 ± 3 au after the removal of gauze and 97 ± 5 au after the removal of foam (P <0.001). For substance P, the staining was 55 ± 3 au after gauze removal and 95 ± 4 au after foam removal (P <0.001). CGRP and substance P staining was primarily located to nerves and leukocytes. The increase in CGRP and substance P immunofluorescence was especially prominent in the dermis but also was seen in subcutaneous and muscle tissue. Using gauze may be one way of reducing NPWT dressing change-related pain. New wound fillers designed to optimize granulation tissue formation and minimize pain issues presumably will be developed in the near future.
Effect of substance P on gene expression of transforming growth factor beta-1 and its receptors in rat's fibroblasts.
Lai Xi-nan,Wang Zheng-guo,Zhu Jin-ming,Wang Li-li
Chinese journal of traumatology = Zhonghua chuang shang za zhi
OBJECTIVE:To investigate the effect of substance P (SP) on gene expression of transforming growth factor beta-1 (TGFbeta-1), transforming growth factor receptor-1 (TGFR-1) and transforming growth factor receptor-2 (TGFR-2) in fibroblasts cultured in vitro from rat's granulation tissues. METHODS:The fibroblasts from the granulation tissues in the skeletal muscle of rat's hind limbs injured by formaldehyde were cultured in vitro. When different concentrations (10(-9)-10(-5) mol/L) of SP were added into the culture medium, the changes of gene expression of TGFbeta-1, TGFR-1 and TGFR-2 in the cultured fibroblasts were observed with reverse transcription polymerase chain reaction at different intervals (0, 3, 6, 12 and 24 hours after incubation). RESULTS:The gene expression of TGFbeta-1, TGFR-1 and TGFR-2 in the fibroblasts cultured from rat's granulation tissues was up-regulated by SP. The peak level of the mRNA expression was found at 10(-8) mol/L SP and the up-regulation effect was not found at 10(-5) mol/L and 10(-6) mol/L. The peak levels of gene expression of TGFbeta-1, TGFR-1 and TGFR-2 in the fibroblasts treated with SP were achieved at 6 and 12 hours, respectively. CONCLUSIONS:SP has up-regulation effect on the gene expression of TGFbeta-1, TGFR-1 and TGFR-2 in fibroblasts from rat's granulation tissues in vitro, and the effect is related to different stimulating concentrations of SP. It may be concerned with proliferation and differentiation of fibroblasts and formation of scar tissues during wound healing.
Neuropeptides: role in inflammatory skin diseases.
Luger T A,Lotti T
Journal of the European Academy of Dermatology and Venereology : JEADV
The cutaneous nervous system recently has been demonstrated to interact with multiple target cells in the skin and to mediate actions important in inflammatory conditions. Neuropeptides released by cutaneous neurons such as substance P (SP), vasointenstinal peptide (VIP), calcitonine gene regulated peptide (CGRP), proopiomelancortin (POMC) peptides and others modulate the function of immunocompetent and inflammatory cells as well as epithelial and endothelial cells. They have been found to function as mediators of cell proliferation, cytokine and growth factor production as well as adhesion molecule and cell surface receptor expression. In addition many cells including keratinocytes, fibroblasts, endothelial cells and inflammatory cells have been shown to release several neuropeptides and they express their corresponding receptors. These findings indicate that neuropeptides participate in the complex network of mediators that regulate cutaneous inflammation, hyperproliferation and wound healing.
[Regulative effects and significance of substance P on the expression of basic fibroblast growth factor of granulation tissue fibroblasts in vitro].
Jiang Wei,Wang Zheng-guo,Lai Xi-nan,Zhu Jin-ming,Zhu Pei-fang
Zhonghua shao shang za zhi = Zhonghua shaoshang zazhi = Chinese journal of burns
OBJECTIVE:To explore the regulative effects and significance of neuropeptide substance P (SP) on the expression of basic fibroblast growth factor (bFGF) of granulation tissue fibroblasts in vitro. METHODS:A local aseptic inflammation was induced by injection of formaldehyde in rats, and its granulation tissue was cultured. RT-PCR was employed to observe expression of bFGF mRNA after inducement of SP at different concentrations and time points in the granulation tissue, and western blot to assay expression of bFGF protein. RESULTS:The expression of bFGF mRNA was markedly increased significantly 3 and 6 hours after inducement with SP in 10(-7) mol/L, compared with control group (P < 0.01). The expression of bFGF protein was markedly higher than the control group after 12 hours, and it reached the peak at the 24th hour and declined gradually after 48 hours. SP at concentrations of 10(-9) - 10(-5) mol/L could significantly promote the expression of bFGF mRNA, and that at 10(-8) - 10(-5) mol/L induce the expression of bFGF protein. Both expressions reached the peak when SP concentration was 10(-7) mol/L (P < 0.01). CONCLUSION:SP can induce the expressions of bFGF mRNA and bFGF protein of granulation tissue fibroblasts in vitro, which may possess an important significance in wound healing.
Angiotensin II stimulates canonical TGF-β signaling pathway through angiotensin type 1 receptor to induce granulation tissue contraction.
Ehanire Tosan,Ren Licheng,Bond Jennifer,Medina Manuel,Li George,Bashirov Latif,Chen Lei,Kokosis George,Ibrahim Mohamed,Selim Angelica,Blobe Gerard C,Levinson Howard
Journal of molecular medicine (Berlin, Germany)
UNLABELLED:Hypertrophic scar contraction (HSc) is caused by granulation tissue contraction propagated by myofibroblast and fibroblast migration and contractility. Identifying the stimulants that promote migration and contractility is key to mitigating HSc. Angiotensin II (AngII) promotes migration and contractility of heart, liver, and lung fibroblasts; thus, we investigated the mechanisms of AngII in HSc. Human scar and unwounded dermis were immunostained for AngII receptors angiotensin type 1 receptor (AT1 receptor) and angiotensin type 2 receptor (AT2 receptor) and analyzed for AT1 receptor expression using Western blot. In vitro assays of fibroblast contraction and migration under AngII stimulation were conducted with AT1 receptor, AT2 receptor, p38, Jun N-terminal kinase (JNK), MEK, and activin receptor-like kinase 5 (ALK5) antagonism. Excisional wounds were created on AT1 receptor KO and wild-type (WT) mice treated with AngII ± losartan and ALK5 and JNK inhibitors SB-431542 and SP-600125, respectively. Granulation tissue contraction was quantified, and wounds were analyzed by immunohistochemistry. AT1 receptor expression was increased in scar, but not unwounded tissue. AngII induced fibroblast contraction and migration through AT1 receptor. Cell migration was inhibited by ALK5 and JNK, but not p38 or MEK blockade. In vivo experiments determined that absence of AT1 receptor and chemical AT1 receptor antagonism diminished granulation tissue contraction while AngII stimulated wound contraction. AngII granulation tissue contraction was diminished by ALK5 inhibition, but not JNK. AngII promotes granulation tissue contraction through AT1 receptor and downstream canonical transforming growth factor (TGF)-β signaling pathway, ALK5. Further understanding the pathogenesis of HSc as an integrated signaling mechanism could improve our approach to establishing effective therapeutic interventions. KEY MESSAGE:AT1 receptor expression is increased in scar tissue compared to unwounded tissue. AngII stimulates expression of proteins that confer cell migration and contraction. AngII stimulates fibroblast migration and contraction through AT1 receptor, ALK5, and JNK. AngII-stimulated in vivo granulation tissue contraction is AT1 receptor and ALK5 dependent.
10.1007/s00109-014-1211-9
The reinnervation pattern of wounds and scars may explain their sensory symptoms.
Henderson J,Terenghi G,McGrouther D A,Ferguson M W J
Journal of plastic, reconstructive & aesthetic surgery : JPRAS
Anaesthesia, pruritus and pain are common in cutaneous scars. The reinnervation pattern of healing wounds and scars might help to explain these symptoms, as sensory neurotransmitters are known to be mediators of inflammation and healing. We quantified the regeneration patterns of blood vessels and nerves in excisional skin wounds as they matured into scars. Mice underwent 1cm(2) full thickness skin excisions. Wounds were harvested between five and 84 days. Sections underwent immunohistochemical staining for protein gene product 9.5 (PGP9.5) a pan-neuronal marker, and the sensory neuropeptides calcitonin gene related peptide (CGRP) and substance P (SP). The endothelial marker von Willebrand factor (VWF) was used to allow co-localisation and quantification of blood vessels. Nerve fibre density was quantified at multiple sites within wounds. There was no difference in the reinnervation/revascularisation pattern between peripheral and central sites. The density of PGP9.5, CGRP, SP and VWF peaked between 14 and 42 days, and levels of PGP9.5, CGRP and VWF all decreased to approximately those found in unwounded skin by 84 days (mature scar). SP levels, however, remained elevated at approximately twice the density found in unwounded skin. Increased densities of SP and CGRP in healing wounds could explain the unpleasant sensory symptoms of healing wounds.
10.1016/j.bjps.2005.11.038
Sensory innervation of normal and hypospadiac prepuce: possible implications in hypospadiology.
Nazir Zafar,Masood Rehan,Rehman Resham
Pediatric surgery international
Sensory innervation of the skin influences wound healing through the release of neuropeptides from the nerve endings. The purpose of this study was to investigate the differences in the sensory innervation of the normal and the hypospadiac prepuce. The prepuce from 10 healthy children undergoing routine circumcision and 10 age-matched children undergoing hypospadias repair were submitted for immunohistochemistry, using antibodies against protein gene product (PGP) 9.5, calcitonin gene-related peptide (CGRP), and substance P (SP). The hypospadiac prepuce was found to be hypo-innervated for PGP 9.5 and CGRP positive nerves when compared with the normal prepuce ( p<0.05). The number of SP-positive nerves were increased in the hypospadiac prepuce, but not to statistical significance ( p=0.06, confidence interval >95%). There may be differences in the sensory innervation of the normal and hypospadiac prepuce. These differences in tissue environment may partly explain the postoperative edema, poor wound healing leading to urethrocutaneous fistula (UF), and increased analgesia requirements in patients undergoing hypospadias surgery.
10.1007/s00383-004-1244-1
Substance P induces M2-type macrophages after spinal cord injury.
Jiang Mei H,Chung Eunkyung,Chi Guang F,Ahn Woosung,Lim Ji E,Hong Hyun S,Kim Dae W,Choi Hyeongwon,Kim Jiyoung,Son Youngsook
Neuroreport
The potential benefits or the tissue-damaging effects of inflammatory response after central nervous system injuries have long been disputed. Recent studies have noted that substance P (SP), a neuropeptide, plays an important role in the wound-healing process by recruiting bone marrow stem cells to the injured tissue. In this study, we examined whether SP can enhance recovery from spinal cord injury (SCI) in Sprague-Dawley rats through its known function of stem cell mobilization and/or through the modulation of inflammation. We examined proinflammatory and anti-inflammatory cytokines and markers for macrophage subtypes. SP treatment modulated the SCI microenvironment toward a more anti-inflammatory and reparative one by inducing interleukin-10 and M2 macrophages and suppressing inducible nitric oxide synthase and tumor necrosis factor-α. This modulation was achieved at 1 day much earlier than SP-stimulated bone marrow stem cells' mobilization. Early intervention of the devastating inflammatory response by SP treatment caused the lesion cavity to become filled with robust axonal outgrowth that overlaid the M2 macrophages at 2 weeks--all of which culminated in tissue sparing and improvement in functional recovery from the SCI. SP is therefore a potential anti-inflammatory modulator for the treatment of injury-induced inflammatory central nervous system disorders.
10.1097/WNR.0b013e3283572206
Effects of substance P on growth of fibroblast-like cells derived from bile duct: an in vitro cell culture study.
Tian Yuanhu,Yang Guangyun,Zhang Xiaoqing,Shen Wei,Dong Jiahong,Xu Zhi
Chinese medical journal
BACKGROUND:The possible role of substance P (SP) during wound healing has been the primary research focus in recent years, but its effect on the healing process after bile duct injury is little understood. This study aimed to investigate the effects of SP on growth of fibroblast-like cells derived from rabbit bile duct. METHODS:Fibroblast-like cells derived from rabbit bile duct were identified and divided randomly into control and experimental groups. SP-treated cells at different concentrations of 10(-9)-10(-5) mol/L and control group were incubated, respectively, for 48 hours. After incubating, the effects of SP on cell proliferation were assessed by cell counts and MTT test. Apoptosis rate (AR) of cells was measured by flow cytometry. RESULTS:Cultured rabbit bile duct cells were fibroblast-like in morphology, and these cells were stained positively for vimentin and negatively for desmin. After SP was added to nonconfluent cells for 48 hours, cell numbers were significantly increased in experimental groups than in controls (P < 0.05). The maximum stimulation of cell proliferation was achieved at SP of 10(-5) mol/L. Bile duct fibroblast-like cells in the SP group showed a higher proliferating activity and lower AR than those in the control group or in the SP + Spantide group (P < 0.05). Spantide partly inhibited the effects of SP on fibroblast-like cells. Examination under transmission electron microscopy revealed rough endoplasmic reticulum and prominent Golgi complexes after SP treatment. CONCLUSIONS:SP has a growth regulatory property on cultivated bile duct fibroblast-like cells in vitro, suggesting that SP may involve in wound healing after bile duct injury by promoting wound fibroblast proliferation and inhibiting apoptosis and participate in pathological scar formation.
Intermittent pneumatic compression enhances neurovascular ingrowth and tissue proliferation during connective tissue healing: a study in the rat.
Dahl Johan,Li Jian,Bring Daniel K-I,Renström Per,Ackermann Paul W
Journal of orthopaedic research : official publication of the Orthopaedic Research Society
Intermittent pneumatic compression (IPC) is a treatment method to decrease venous stasis and stimulate blood flow. Recently, it was hypothesized that IPC may exert positive effects on tissue healing, a process highly dependent upon adequate circulation. In this study, we investigated the effects of daily 1-h IPC treatment during 2 and 4 weeks post-rat Achilles tendon rupture. The tendons were subjectively and semiquantitatively analyzed for collagen organization, fibroblast density, angiogenesis, and the occurrence of sensory neuropeptides, substance P (SP) and calcitonine gene related peptide (CGRP), as well as for a nerve regeneration marker, growth associated protein 43 (GAP-43). After 2 weeks of treatment, fibroblast density increased by 53% (p = 0.0004), vessel density by 64% (p = 0.022), and the occurrence of SP by 110% (p = 0.047) and CGRP by 47% (p = 0.0163) compared to untreated controls. Following 4 weeks of treatment, both the occurrence of sensory neuropeptides and the vessel density remained significantly higher (p < 0.05), whereas fibroblast density returned to normal. However, at 4 weeks the treated tendons displayed a higher degree of organized parallel collagen fibers, a sign of increased maturation. Daily IPC treatment improves neurovascular ingrowth and fibroblast proliferation in the healing tendon and may accelerate the repair process.
10.1002/jor.20390
Effects of ginsenoside Rb1 at low doses on histamine, substance P, and monocyte chemoattractant protein 1 in the burn wound areas during the process of acute burn wound repair.
Kawahira Kazuhiro,Sumiyoshi Maho,Sakanaka Masahiro,Kimura Yoshiyuki
Journal of ethnopharmacology
AIM OF THE STUDY:We reported recently that the facilitating effects of ginsenosid Rb(1) on burn wound-healing might be due to the promotion of angiogenesis. Increased histamine, substance P (SP), and monocyte chemoattractant protein (MCP)-1 levels caused inflammation, and pain following severe burn wound injury. MATERIALS AND METHODS:We examined the effects of ginsenoside Rb1 on the histamine, SP, and MCP-1 levels in burn wound tissue during burn wound repair. RESULTS AND CONCLUSIONS:Ginsenoside Rb1 (1 ng/wound) and basic fibroblast growth factor (bFGF) (2.5 microg/wound) significantly increased the levels of MCP-1 on day 1 compared to the MCP-1 level in vehicle-treated mice. Histamine production of the burn wound area on day 7 was increased by topical application of ginsenoside Rb1 (100 fg-1 ng/wound) and bFGF. The number of mast cells migrating to the burn wound area was also increased by ginsenoside Rb1. Conversely, the increased SP production was reduced by ginsenoside Rb1. This finding suggests that the pain induction by burn injury may be reduced by ginsenoside Rb1. The facilitating actions of ginsenoside Rb1 on burn wound healing may be due to the increase in histamine production via the increase in mast cell migration to the burn wound area induced by the rapid elevation of MCP-1.
10.1016/j.jep.2008.01.032
Angiogenesis induced by controlled release of neuropeptide substance P.
Kohara Hiroshi,Tajima Shuhei,Yamamoto Masaya,Tabata Yasuhiko
Biomaterials
The in vivo recruitment of circulating host cells to the site to be regenerated is one of the promising strategies for therapeutic angiogenesis. Substance P (SP), a member of neuropeptides, mediates pain perception and regulates wound healing, inflammation, tumor cell proliferation, and angiogenesis. This SP enhanced the migration, adhesion, and angiogenic gene expression of granulocytes in vitro. A biodegradable hydrogel was prepared from an anionic derivative of gelatin to achieve the controlled release of SP in vivo. When the anionic gelatin hydrogels incorporating SP were subcutaneously implanted into the mouse back, significant angiogenesis was induced around the site implanted, in contrast to the injection of SP solution. In vivo accumulation of granulocytes around the implanted sites was observed. It is concluded that the controlled release of SP efficiently induced the recruitment and the subsequent activation of granulocytes, one of the circulating cells with angiogenic activities, from the blood circulation into the site implanted, resulting in enhanced angiogenesis.
10.1016/j.biomaterials.2010.07.079
Diminished neuropeptide levels contribute to the impaired cutaneous healing response associated with diabetes mellitus.
Gibran Nicole S,Jang Young Chul,Isik F Frank,Greenhalgh David G,Muffley Lara A,Underwood Robert A,Usui Marcia L,Larsen Jerrie,Smith Douglas G,Bunnett Nigel,Ansel John C,Olerud John E
The Journal of surgical research
Background. Patients with diabetic sensory neuropathy have significant risk of chronic ulcers. Insufficient nerve-derived mediators such as substance P (SP) may contribute to the impaired response to injury. Mutant diabetic mice (db/db), which develop neuropathy and have delayed healing, may provide a model to study the role of nerves in cutaneous injury.Methods. Skin from human chronic nonhealing ulcers and age-matched control skin was immunohistochemically evaluated for nerves. Nerve counts were also compared in murine diabetic (C57BL/KsJ-m+/+ Lepr(db); db/db) and nondiabetic (db/-) skin. Excisional wounds on the backs of db/db and db/- mice were grouped as: (a) untreated db/- mice; (b) untreated db/db mice; (c) db/db mice with polyethylene glycol (PEG); (d) db/db mice with PEG and SP 10(-9) M; or (e) db/db mice with PEG and SP 10(-6) M.Results. We demonstrated fewer nerves in the epidermis and papillary dermis of skin from human subjects with diabetes. Likewise, db/db murine skin had significantly fewer epidermal nerves than nondiabetic littermates. We confirmed increased healing times in db/db mice (51.7 days) compared to db/- littermates (19.8 days; P </= 0.001). SP 10(-6) M (44 days; P = 0.02) and SP 10(-9) M (45 days; P = 0.03) shortened time to closure compared to PEG treatment alone (68 days). Since there was no difference in the percentage contraction in these treatment groups, SP may favorably promote wound epithelization.Conclusions. Our data support the use of db/db murine excisional wounds to evaluate the role of nerves in healing. We have demonstrated that exogenous SP improves wound healing kinetics in an animal model.
Substance P enhances wound closure in nitric oxide synthase knockout mice.
Muangman Pornprom,Tamura Richard N,Muffley Lara A,Isik F Frank,Scott Jeffrey R,Xie Chengyu,Kegel Gary,Sullivan Stephen R,Liang Zhi,Gibran Nicole S
The Journal of surgical research
INTRODUCTION:The neuropeptide, substance P (SP), up-regulates nitric oxide production (NO). The purpose of this study was to determine whether SP enhances response to cutaneous injury in nitric oxide synthase knockout (NOS null) mice. METHODS:We studied mice with targeted deletions of the 3 NOS genes, neuronal NOS, inducible NOS, or endothelial NOS. Full thickness dorsal wounds were treated daily (d 0-6) with topical SP or normal saline (NaCl). Wounds were analyzed by flow cytometry for macrophage, leukocyte, endothelial, and dendritic cells. Healing time and wound epithelialization were compared using analysis of variance. RESULTS:Wound closure in the 3 NOS null mice was slower than the control mice (P < 0.05). SP treatment enhanced wound closure in NOS null mice (P < 0.02). NOS null wounds exhibited reduced inflammation. SP increased macrophage, leukocyte, and dendritic cell densities at d 3 and d 7 (P < 0.05) in all NOS null mice. SP increased endothelial cell number in neuronal NOS and inducible NOS null mice, but not in endothelial NOS null mice (P > 0.05). CONCLUSIONS:SP ameliorated the impaired wound healing response observed in NOS null mice by enhancing wound closure kinetics and epithelialization. SP increased inflammatory cell density in the wounds supporting the essential role of inflammatory cells, especially macrophages, in wound repair.
10.1016/j.jss.2008.03.051
Chemokine expression of CCL2, CCL3, CCL5 and CXCL10 during early inflammatory tendon healing precedes nerve regeneration: an immunohistochemical study in the rat.
Stålman A,Bring D,Ackermann P W
Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA
PURPOSE:Chemokines are major promoters of repair and may regulate nerve ingrowth that is essential in tendon healing. The purpose of this study was to assess the temporal occurrence of different chemokines during Achilles tendon healing in relation to sensory nerve regeneration. Chemokine presence in tendon healing has not been studied previously. METHODS:Chemokine expression, nerve regeneration, angiogenesis and inflammatory cell occurrence during healing of Achilles tendon rupture in the rat were studied by immunohistochemistry and histology including semiquantitative assessment. Markers for chemokines (CCL5, CCL2, CCL3, CXCL10), nerves (PGP-9.5) and sensory neuropeptide substance P (SP) were analysed at different time points (1 day-16 weeks) post-rupture. RESULTS:In intact tendons (controls) immunoreactivity to all chemokines, PGP-9.5 and SP were confined to the tendon surroundings. After rupture, there was rapid increase in the tendon proper of the chemokines studied, all exhibiting their peak expression at week 1. Subsequently, at weeks 2-6, emerging inflammatory cells and maximum sprouting of PGP-/SP-positive nerves were observed close to newly formed blood vessels within the tendon proper, while chemokine expression already decreased. During weeks 6-8, PGP-/SP-positive nerves withdrew from the rupture site and relocated together with the chemokines in the surrounding tendon. CONCLUSIONS:Early chemokine expression in the healing tendon precedes ingrowth of new nerves, angiogenesis and emergence of inflammatory cells. The fine-tuned temporal and spatial appearance of chemokines suggests a chemoattractant role for inflammatory cell migration and possibly also a role in angiogenesis and neurogenesis. Chemokines may thus exhibit vital targets for biological modulation of tendon repair.
10.1007/s00167-014-3010-9
Substance P and fibrotic diseases.
Peng Lei,Agogo George O,Guo Jianqiang,Yan Ming
Neuropeptides
Substance P (SP) is an undecapeptide encoding the tachykinin 1 (TAC1) gene and belongs to the tachykinin family. SP is widely distributed in the central nervous system and the peripheral nervous system. SP is also produced by nonneuronal cells, such as inflammatory cells and endothelial cells. The biological activities of SP are mainly regulated through the high-affinity neurokinin 1 receptor (NK-1R). The SP/NK-1R system plays an important role in the molecular bases of many human pathophysiologic processes, such as pain, infectious and inflammatory diseases, and cancer. In addition, this system has been implicated in fibrotic diseases and processes such as wound healing, myocardial fibrosis, bowel fibrosis, myelofibrosis, renal fibrosis, and lung fibrosis. Recently, studies have shown that SP plays an important role in liver fibrosis and that NK-1R antagonists can inhibit the progression of fibrosis. NK-1R receptor antagonists could provide clinical solutions for fibrotic diseases. This review summarizes the structure and function of SP and its involvement in fibrotic diseases.
10.1016/j.npep.2019.101941
Immunohistochemical analysis of neuropeptides (protein gene product 9.5, substance P and calcitonin gene-related peptide) in hypertrophic burn scar with pain and itching.
Kwak In Suk,Choi Young Hee,Jang Young Chul,Lee Yoon Kyung
Burns : journal of the International Society for Burn Injuries
BACKGROUND:Neuropeptides have been recently reported as having an important role in wound repair, and relief from pain and itching sensation. The aim of this study was to evaluate the effect of neuropeptides on the wound healing process in hypertrophic scar formation that accompanies severe pain and itching sensation. METHODS:We collected forty-three hypertrophic scar specimens from hypertrophic scar release and skin graft under general anesthesia. Immunohistochemical stains for protein gene product (PGP) 9.5, substance P (SP), and calcitonin gene-related peptide (CGRP) were performed. Pain and itching over the scar were recorded using verbal numerical rating scale (VNRS). RESULTS:In the epidermis, PGP 9.5, SP, and CGRP were significantly increased in hypertrophic scars compared with matched unburned skin. In the reticular dermis, SP and CGRP were significantly increased in hypertrophic scars compared with control. The pain and itching verbal numerical rating scale in scar group were significantly higher compared to control. In the papillary dermis, the PGP represented significant correlation with Itching P (correlation coefficient 0.698) and the SP represented significant correlation with pain N (correlation coefficient -0.671). In the reticular dermis, the SP represented significant correlation with pain N (correlation coefficient -0.614) and CGRP represented significant correlation with pain P/Itching P (correlation coefficient 0.801/0.611). CONCLUSIONS:Neuropeptides such as PGP 9.5, SP, and CGRP seem to affect scarring via sensory neurotransmission, it have a regulatory role for pain and itching sensation in hypertrophic scars.
10.1016/j.burns.2014.04.004
Double-edged effects of neuropeptide substance P on repair of cutaneous trauma.
Jing Chen,Jia-Han Wang,Hong-Xing Zhuang
Wound repair and regeneration : official publication of the Wound Healing Society [and] the European Tissue Repair Society
To explore further the role of substance P (SP) in wound healing and scar formation, SP concentrations in wounds of scalded rats were assayed. Expressions of apoptosis-associated genes in fibroblasts cultured with SP were detected. SP concentrations in superficial wounds increased earlier than those in deep wounds. SP was associated with an increased proliferation and a decreased apoptosis of fibroblasts. It had a greater influence on keloid fibroblasts than on hypertrophic scar fibroblasts by elevating the expression of proliferating cell nuclear antigen and BCL-2 in fibroblasts. Spantide completely suppressed the effects of SP on hypertrophic scar fibroblasts, and partly inhibited its effects on keloid scar fibroblasts. SP may play an important role in wound healing by promoting wound fibroblast proliferation and inhibiting apoptosis. It may also participate in pathological scar formation by modulating the expression of apoptosis-associated genes. SP is postulated to play a dual role in wound repair.
10.1111/j.1524-475X.2010.00589.x
Keratinocytes express cytokines and nerve growth factor in response to neuropeptide activation of the ERK1/2 and JNK MAPK transcription pathways.
Shi Xiaoyou,Wang Liping,Clark J David,Kingery Wade S
Regulatory peptides
Sensory neurons innervating the skin can release neuropeptides that are believed to modulate cellular proliferation, wound healing, pigmentation, and keratinocyte innate immune responses. While the ability of neuropeptides to stimulate keratinocyte production of inflammatory mediators has been demonstrated, there is no information concerning the mechanisms by which neuropeptide activation of keratinocyte cell surface receptors ultimately leads to the up-regulation of mediator production. In this study we used a keratinocyte cell line to identify the presence of substance P (SP) and calcitonin gene-related peptide (CGRP) receptors on keratinocytes and examined the effects of SP and CGRP stimulation on keratinocyte neuropeptide signaling, cell proliferation, and interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor α (TNF-α), and nerve growth factor (NGF) expression. Neuropeptide stimulation caused an up-regulation of neuropeptide receptor expression in keratinocytes and a dramatic increase in keratinocyte secretion of SP and CGRP, suggesting possible autocrine or paracrine stimulatory effects and amplification of neuropeptide signaling. Both SP and CGRP concentration-dependently stimulated cellular proliferation and the expression and secretion of inflammatory cytokines and NGF in keratinocytes. SP also activated all 3 families of mitogen activated protein kinase (MAPK) and nuclear factor κB (NFκB) in keratinocytes, while CGRP only activated p38 and extracellular signal related kinase1/2 (ERK1/2) MAPKs. Neuropeptide stimulated inflammatory mediatory production in keratinocytes was reversed by ERK1/2 and JNK inhibitors. The current study is the first to observe; 1) that CGRP stimulates keratinocyte expression of CGRP and its receptor complex, 2) that SP and CGRP stimulate IL-6 and TNF-α secretion in keratinocytes, 3) that SP activated all three MAPK families and the NFκB transcriptional signaling pathway in keratinocytes, and 4) that SP and CGRP stimulated inflammatory mediator production in keratinocytes is dependent on ERK1/2 and JNK activation. These studies provide evidence suggesting that disruption of ERK1/2 and JNK signaling may potentially be an effective therapy for inflammatory skin diseases and pain syndromes mediated by exaggerated sensory neuron-keratinocyte signaling.
10.1016/j.regpep.2013.08.001
Sensory nerve-derived neuropeptides accelerate the development and fibrogenesis of endometriosis.
Liu Xishi,Yan Dingmin,Guo Sun-Wei
Human reproduction (Oxford, England)
STUDY QUESTION:Do sensory nerves play any role in the development of endometriosis? SUMMARY ANSWER:Sensory nerves participate in all major steps (epithelial-mesenchymal transition (EMT), fibroblast-to-myofibroblast transdifferentiation (FMT) and smooth muscle metaplasia (SMM)) in the development and fibrogenesis of endometriotic lesions. WHAT IS KNOWN ALREADY:Endometriotic lesions are known to be hyperinnervated due to neurogenesis resulting from neutrophins secreted by endometriotic lesions and possibly platelets. These neutrophins seem to preferentially favour production of sensory neurons at the expense of sympathetic neurons. STUDY DESIGN, SIZE, DURATION:Three independent, yet complementary, prospective, randomized mouse experimentations were conducted. A total of 143 female Balb/C mice and 24 female immunodeficient nude Balb/C mice were used. The mice were sacrificed 2 or 4 weeks after the induction of endometriosis. PARTICIPANTS/MATERIALS, SETTING, METHODS:In Experiment 1, 21 mice were randomly divided into three groups of equal size for sympathetic denervation, sensory denervation and controls. Denervation was carried out chemically. In Experiment 2, 24 nude mice were randomly divided into three equal-sized groups: the BEFORE and AFTER groups that respectively received surgical denervation 3 days before or after the induction of endometriosis by subcutaneous grafting of human endometriotic tissues, and the Control group that received a sham surgery without denervation 3 days before induction. For Experiments 1 and 2, all mice were sacrificed two weeks after induction of endometriosis. In Experiment 3, substance P (SP) and aprepitant, a potent and selective neurokinin 1 receptor (NK1R) antagonist, were used to activate and inhibit the NK1R signalling pathway, respectively. A total of 32 mice were randomly divided into four groups of equal sizes: control (CTL), SP, Before-Induction and After-Induction. One day before the induction of endometriosis, mice in CTL, SP and Before-Induction groups were infused with sterile saline, SP and aprepitant, respectively, via Alzet osmotic pumps. Two weeks after the induction, the After-induction group was infused with aprepitant in similar fashion. All mice were sacrificed four weeks after the induction of endometriosis. In all three experiments, the bodyweight and hotplate latency were evaluated before induction and sacrifice. In addition, all lesions were excised, weighed and processed for quantification and immunohistochemistry analysis of markers for EMT, FMT and SMM, and the extent of fibrosis was evaluated by Masson trichrome staining. MAIN RESULTS AND THE ROLE OF CHANCE:In Experiment 1, chemical denervation of sympathetic and sensory nerves reduced the lesion weight by 43.2% (±23.1%) and 68.7% (±20.3%), respectively, as compared with controls. In particular, sensory denervation led to significantly greater reduction in lesion weight than sympathetic denervation. Sensory denervation also resulted in significantly improved hyperalgesia as compared with controls. In contrast, sympathetic denervation yielded only transient improvement in hyperalgesia. Both sympathetic and sensory denervation resulted in lower immunoreactivity against markers of proliferation and fibrosis, especially sensory denervation.In Experiment 2, surgical denervation before or after induction of endometriosis also decelerated the development of endometriosis, as manifested by significantly reduced lesion weight and extent of lesional fibrosis, along with improved hyperalgesia.In Experiment 3, NK1R activation by SP infusion accelerated lesional development, as evidenced by significantly increased lesional weight, more thorough progression of EMT, FMT, SMM, exaggerated lesional fibrosis and deteriorated hyperalgesia. In contrast, NK1R antagonism decelerated lesional development and improved hyperalgesia. LARGE SCALE DATA:N/A. LIMITATIONS, REASONS FOR CAUTION:This study is limited by the use of histologic and immunohistochemistry analyses only and the lack of molecular data. WIDER IMPLICATIONS OF THE FINDINGS:Since sensory nerves are known to be important in wound healing and fibrogenesis, our findings also give more credence to the notion that endometriotic lesions are wounds undergoing repeated tissue injury and repair. As such, sensory nerves or the NK1R signalling pathway in particular may be potential targets for intervention. STUDY FUNDING/COMPETING INTEREST(S):This research was supported by Grants 81471434 (SWG), 81530040 (SWG), 81771553 (SWG), 81671436 (XSL) and 81871144 (XSL) from the National Natural Science Foundation of China and an Excellence in Centres of Clinical Medicine grant (2017ZZ01016) from the Science and Technology Commission of Shanghai Municipality. None of the authors have anything to disclose.
10.1093/humrep/dey392
Substance P accelerates wound repair by promoting neovascularization and preventing inflammation in an ischemia mouse model.
Kim Suna,Piao Jiyuan,Hwang Dae Yeon,Park Jeong Seop,Son Youngsook,Hong Hyun Sook
Life sciences
AIMS:Arterial insufficiency ulcers are frequent complications of peripheral artery disease and infection or long-term neglect of the ulcer can eventually lead to amputation of the affected body part. An ischemic environment, caused by interrupted blood flow, affects the supply of nutrients and elongates the inflammation period, inducing tissue degeneration. Thus, the modulation of neovascularization and inflammation could be an ideal therapeutic strategy for ischemic wound healing. This study aimed to elucidate whether systemically administered substance P (SP) could promote ischemic wound repair in mice by restoring blood perfusion and suppressing inflammation. MAIN METHODS:The effects of SP were assessed by analyzing wound size, blood flow, epidermal and dermal layer regeneration, vessel formation, and the inflammatory cytokine profiles in a hind-limb ischemia non-clinical mouse model. KEY FINDINGS:SP-treated mice exhibited dramatically rapid wound healing and restoration of blood flow within the ischemic zone, compared with saline-treated mice. Notably, SP-treated mice showed enhanced pericyte-covered vasculature compared to saline-treated mice. Moreover, anti-inflammatory effects were detected in mice in the SP-treated group, including suppression of inflammation-mediated spleen enlargement, reduction of tumor necrosis factor-alpha, and promotion of circulatory interleukin-10 levels. SIGNIFICANCE:These results suggest that SP could be a possible therapeutic candidate for patients with peripheral artery disease, including those with ischemic ulcers.
10.1016/j.lfs.2019.04.015
[Experimental study on the relationship between neuropeptide substance P and wound healing in scalded rats].
Chen Jing,Wang Jia-han,Zhuang Hong-xing,Ren Jia-liang,Li Zhi-qing,Yi Chao-hui
Zhonghua shao shang za zhi = Zhonghua shaoshang zazhi = Chinese journal of burns
OBJECTIVE:To explore the relationship between neuropeptide substance P (SP) and wound healing in scalded rats. METHODS:(1) Scalded rats with different degrees of scald injury were employed as the experimental model and were sacrificed at 24 post scald hour (PSH), and on 3, 7 and 14 post scald days (PSD). The SP content in the wound was detected with radioimmunoassay method. (2) The murine granulation tissue fibroblasts (GTF) were cultured with different culture media, and divided into control, SP and Spantide (SP receptor antagonism) groups. The effects of SP and Spantide on the cellular activity and apoptotic rate of murine GTF were assessed in vitro. RESULTS:There was significant difference of the SP content among the superficial (145 +/- 78) ng/g, partial (94 +/- 48 ng/g) and full thickness (53 +/- 27 ng/g) scald wounds at 24 PSH (P < 0.01), while the SP content in partial thickness burn wound on 3 and 7 PSD obviously increased; and that in deep partial thickness burn wound obviously increased on 7 and 14 PSD. But the SP content remained unchanged in full thickness scald wound. (2) SP could promote the activity of GTF and inhibit its apoptosis (The GTF activity in control, SP groups were 0.21 +/- 0.05, 0.36 +/- 0.07, respectively, P < 0.01). Spantide could inhibit the interaction between SP and GTF. CONCLUSION:SP can promote GTF proliferation, and the SP content in wound is closely associated with the depth of the injury and wound healing capacity.
Expression Profiles of Neuropeptides, Neurotransmitters, and Their Receptors in Human Keratocytes In Vitro and In Situ.
Słoniecka Marta,Le Roux Sandrine,Boman Peter,Byström Berit,Zhou Qingjun,Danielson Patrik
PloS one
Keratocytes, the quiescent cells of the corneal stroma, play a crucial role in corneal wound healing. Neuropeptides and neurotransmitters are usually associated with neuronal signaling, but have recently been shown to be produced also by non-neuronal cells and to be involved in many cellular processes. The aim of this study was to assess the endogenous intracellular and secreted levels of the neuropeptides substance P (SP) and neurokinin A (NKA), and of the neurotransmitters acetylcholine (ACh), catecholamines (adrenaline, noradrenaline and dopamine), and glutamate, as well as the expression profiles of their receptors, in human primary keratocytes in vitro and in keratocytes of human corneal tissue sections in situ. Cultured keratocytes expressed genes encoding for SP and NKA, and for catecholamine and glutamate synthesizing enzymes, as well as genes for neuropeptide, adrenergic and ACh (muscarinic) receptors. Keratocytes in culture produced SP, NKA, catecholamines, ACh, and glutamate, and expressed neurokinin-1 and -2 receptors (NK-1R and NK-2R), dopamine receptor D2, muscarinic ACh receptors, and NDMAR1 glutamate receptor. Human corneal sections expressed SP, NKA, NK-1R, NK-2R, receptor D2, choline acetyl transferase (ChAT), M3, M4 and M5 muscarinic ACh receptors, glutamate, and NMDAR1, but not catecholamine synthesizing enzyme or the α1 and β2 adrenoreceptors, nor M1 receptor. In addition, expression profiles assumed significant differences between keratocytes from the peripheral cornea as compared to those from the central cornea, as well as differences between keratocytes cultured under various serum concentrations. In conclusion, human keratocytes express an array of neuropeptides and neurotransmitters. The cells furthermore express receptors for neuropeptides/neurotransmitters, which suggests that they are susceptible to stimulation by these substances in the cornea, whether of neuronal or non-neuronal origin. As it has been shown that neuropeptides/neurotransmitters are involved in cell proliferation, migration, and angiogenesis, it is possible that they play a role in corneal wound healing.
10.1371/journal.pone.0134157
Substance P promotes diabetic wound healing by modulating inflammation and restoring cellular activity of mesenchymal stem cells.
Park Ju Hyeong,Kim Suna,Hong Hyun Sook,Son Youngsook
Wound repair and regeneration : official publication of the Wound Healing Society [and] the European Tissue Repair Society
Diabetic ulceration is one of the most debilitating complications of diabetes and is the main cause of amputation. The diabetic environment is characterized by prolonged inflammation and abnormal angiogenesis, leading to delayed wound healing. Thus, regulation of inflammation and neovascularization is considered a desirable target for diabetes. The critical purpose of this study was to determine whether systemically administered Substance P (SP) could promote wound healing in diabetic environments via suppression of inflammation, induction of angiogenesis, and mobilization of stem cells. The effect of SP was assessed by analyzing epidermal and dermal recovery, vessel formation, cytokine secretion profile, and the stem cell pool in the circulation and bone marrow. Compared with the vehicle-treated group, the SP-treated group exhibited more rapid wound coverage, reduced infiltration of leukocytes, suppression of injury-mediated enlargement of the spleen and mesenteric lymph nodes, reduced tumor necrosis factor-alpha levels, increased interleukin-10, elevated pool of M2 monocytes and vascular endothelial growth factor levels in the blood. Moreover, the stem cell pool in the bone marrow, which is very low in diabetes, was markedly restored by SP to normal levels, which could provide a favorable environment to facilitate wound healing in diabetes. This result demonstrates, for the first time, a possible application of SP for the treatment of diabetic complications, including diabetic ulcers.
10.1111/wrr.12413
Topical application of substance P promotes wound healing in streptozotocin-induced diabetic rats.
Kant Vinay,Kumar Dinesh,Kumar Dhirendra,Prasad Raju,Gopal Anu,Pathak Nitya N,Kumar Pawan,Tandan Surender K
Cytokine
Substance P (SP) is known to stimulate angiogenesis, fibroblasts proliferation and expressions of cytokines and growth factors involved in wound healing. However, SP level reduces in dermis in diabetics and, hence, it was hypothesized that exogenously applied SP could be helpful in improving wound healing in diabetic rats. Excision skin wound was created on the back of diabetic rats and rats were divided into three groups i.e. (i) saline-, (ii) gel- and (iii) SP-treated. Normal saline, pluronic gel and SP (10(-6)M) in gel were topically applied once daily for 19days. SP treatment significantly increased the wound closure, levels of interleukin-10, and expressions of vascular endothelial growth factor, transforming growth factor-beta1, heme oxygenase-1 and endothelial nitric oxide synthase, whereas it significantly decreased the expression of tumor necrosis factor-alpha, interleukin-1beta and matrix metalloproteinases-9 in the granulation/healing tissue. The inflammatory cells were present for long time in normal saline-treated group. Histological evaluation revealed better extracellular matrix formation with marked fibroblast proliferation and collagen deposition in SP-treated group. Early epithelial layer formation, increased microvessel density and greater growth associated protein-43 positive nerve fibers were also evidenced in SP-treated group. In conclusion, SP treatment markedly accelerated cutaneous wound healing in diabetic rats.
10.1016/j.cyto.2014.12.015
Substance P enhances EPC mobilization for accelerated wound healing.
Um Jihyun,Jung Nunggum,Chin Sukbum,Cho Younggil,Choi Sanghyuk,Park Ki-Sook
Wound repair and regeneration : official publication of the Wound Healing Society [and] the European Tissue Repair Society
Wound healing is essential for the survival and tissue homeostasis of unicellular and multicellular organisms. The current study demonstrated that the neuropeptide substance P (SP) accelerated the wound healing process, particularly in the skin. Subcutaneous treatment of SP accelerated wound closing, increased the population of α-smooth muscle actin positive myofibroblasts, and increased extracellular matrix deposition at the wound site. Moreover, SP treatment enhances angiogenesis without a local increase in the expression levels of vascular endothelial growth factor and stromal cell-derived factor-1. Importantly, SP treatment increased both the population of circulating endothelial progenitor cells in the peripheral blood and in CD31 positive cells in Matrigel plugs. The tube forming potential of endothelial cells was also enhanced by SP treatment. The results suggested that the subcutaneous injection of SP accelerated the wound healing in the skin via better reconstitution of blood vessels, which possibly followed an increase in the systemic mobilization of endothelial progenitor cells and a more effective assembly of endothelial cells into tubes.
10.1111/wrr.12403
Substance P promotes wound healing in diabetes by modulating inflammation and macrophage phenotype.
Leal Ermelindo C,Carvalho Eugénia,Tellechea Ana,Kafanas Antonios,Tecilazich Francesco,Kearney Cathal,Kuchibhotla Sarada,Auster Michael E,Kokkotou Efi,Mooney David J,LoGerfo Frank W,Pradhan-Nabzdyk Leena,Veves Aristidis
The American journal of pathology
Diabetic foot ulceration is a major complication of diabetes. Substance P (SP) is involved in wound healing, but its effect in diabetic skin wounds is unclear. We examined the effect of exogenous SP delivery on diabetic mouse and rabbit wounds. We also studied the impact of deficiency in SP or its receptor, neurokinin-1 receptor, on wound healing in mouse models. SP treatment improved wound healing in mice and rabbits, whereas the absence of SP or its receptor impaired wound progression in mice. Moreover, SP bioavailability in diabetic skin was reduced as SP gene expression was decreased, whereas the gene expression and protein levels of the enzyme that degrades SP, neutral endopeptidase, were increased. Diabetes and SP deficiency were associated with absence of an acute inflammatory response important for wound healing progression and instead revealed a persistent inflammation throughout the healing process. SP treatment induced an acute inflammatory response, which enabled the progression to the proliferative phase and modulated macrophage activation toward the M2 phenotype that promotes wound healing. In conclusion, SP treatment reverses the chronic proinflammatory state in diabetic skin and promotes healing of diabetic wounds.
10.1016/j.ajpath.2015.02.011
Substance P promotes diabetic corneal epithelial wound healing through molecular mechanisms mediated via the neurokinin-1 receptor.
Yang Lingling,Di Guohu,Qi Xia,Qu Mingli,Wang Yao,Duan Haoyun,Danielson Patrik,Xie Lixin,Zhou Qingjun
Diabetes
Substance P (SP) is a neuropeptide, predominantly released from sensory nerve fibers, with a potentially protective role in diabetic corneal epithelial wound healing. However, the molecular mechanism remains unclear. We investigated the protective mechanism of SP against hyperglycemia-induced corneal epithelial wound healing defects, using type 1 diabetic mice and high glucose-treated corneal epithelial cells. Hyperglycemia induced delayed corneal epithelial wound healing, accompanied by attenuated corneal sensation, mitochondrial dysfunction, and impairments of Akt, epidermal growth factor receptor (EGFR), and Sirt1 activation, as well as decreased reactive oxygen species (ROS) scavenging capacity. However, SP application promoted epithelial wound healing, recovery of corneal sensation, improvement of mitochondrial function, and reactivation of Akt, EGFR, and Sirt1, as well as increased ROS scavenging capacity, in both diabetic mouse corneal epithelium and high glucose-treated corneal epithelial cells. The promotion of SP on diabetic corneal epithelial healing was completely abolished by a neurokinin-1 (NK-1) receptor antagonist. Moreover, the subconjunctival injection of NK-1 receptor antagonist also caused diabetic corneal pathological changes in normal mice. In conclusion, the results suggest that SP-NK-1 receptor signaling plays a critical role in the maintenance of corneal epithelium homeostasis, and that SP signaling through the NK-1 receptor contributes to the promotion of diabetic corneal epithelial wound healing by rescued activation of Akt, EGFR, and Sirt1, improvement of mitochondrial function, and increased ROS scavenging capacity.
10.2337/db14-0163
Role of Corneal Stromal Cells on Epithelial Cell Function during Wound Healing.
Kowtharapu Bhavani S,Murín Radovan,Jünemann Anselm G M,Stachs Oliver
International journal of molecular sciences
Following injury, corneal stromal keratocytes transform into repair-phenotype of activated stromal fibroblasts (SFs) and participate in wound repair. Simultaneously, ongoing bi-directional communications between corneal stromal-epithelial cells also play a vital role in mediating the process of wound healing. Factors produced by stromal cells are known to induce proliferation, differentiation, and motility of corneal epithelial cells, which are also subsequently the main processes that occur during wound healing. In this context, the present study aims to investigate the effect of SFs conditioned medium (SFCM) on corneal epithelial cell function along with substance P (SP). Antibody microarrays were employed to profile differentially expressed cell surface markers and cytokines in the presence of SFCM and SP. Antibody microarray data revealed enhanced expression of the ITGB1 in corneal epithelial cells following stimulation with SP whereas SFCM induced abundant expression of IL-8, ITGB1, PD1L1, PECA1, IL-15, BDNF, ICAM1, CD8A, CD44 and NTF4. All these proteins have either direct or indirect roles in epithelial cell growth, movement and adhesion related signaling cascades during tissue regeneration. We also observed activation of MAPK signaling pathway along with increased expression of focal adhesion kinase (FAK), paxillin, vimentin, β-catenin and vasodilator-stimulated phosphoprotein (VASP) phosphorylation. Additionally, epithelial-to-mesenchymal transition (EMT) regulating transcription factors Slug and ZEB1 expression were enhanced in the presence of SFCM. SP enriched the expression of integrin subunits α4, α5, αV, β1 and β3 whereas SFCM increased α4, α5, αV, β1 and β5 integrin subunits. We also observed increased expression of Serpin E1 following SP and SFCM treatment. Wound healing scratch assay revealed enhanced migration of epithelial cells following the addition of SFCM. Taken together, we conclude that SFCM-mediated sustained activation of ZEB1, Slug in combination with upregulated migration-associated integrins and ERK (Extracellular signal-regulated kinase)-FAK-paxillin axis, may lead to induce type 2 EMT-like changes during corneal epithelial wound healing.
10.3390/ijms19020464
Substance P-loaded electrospun small intestinal submucosa/poly(ε-caprolactone)-ran-poly(l-lactide) sheet to facilitate wound healing through MSC recruitment.
Kim Min Ju,Ji Yun Bae,Seo Ji Young,Park Seung Hun,Kim Jae Ho,Min Byoung Hyun,Kim Moon Suk
Journal of materials chemistry. B
In this work, we prepared an electrospun small intestinal submucosa/poly(ε-caprolactone)-ran-poly(l-lactide) (SIS/PCLA) sheet onto which substance P (SP) was loaded, and this was employed as a cell-free scaffold for wound healing through the mobilization of human mesenchymal stem cells (hMSCs). SP release from the SP-loaded scaffold was 42% at 12 h and 51% at 24 h due to an initial burst of SP, but after 1 day, it exhibited a linear release profile and was released at a sustained rate for 21 days. The SP-loaded SIS/PCLA sheet exhibited higher in vitro and in vivo hMSC migration than did the PCLA and SIS/PCLA sheets. Large hMSCs injected into the tail vein of mice models migrated towards the wound to a greater extent in the presence of the SP-loaded SIS/PCLA sheet than with the PCLA and SIS/PCLA sheets, as confirmed by the CD44 and CD29 markers of recruited hMSCs. In animal wound models, significantly higher wound contraction (∼97%) in the group treated with the SP-loaded SIS/PCLA sheet was observed compared with the PCLA (∼74%) and SIS/PCLA (∼84%) groups at 3 weeks. In addition, SP-loaded SIS/PCLA-treated animals showed significant epidermal regeneration and collagen density (56%) in the mature granulation tissue at 3 weeks compared to the PCLA and SIS/PCLA groups. The wound area after SP-loaded SIS/PCLA sheet treatment also showed high blood vessel formation at the early stage, resulting in enhanced wound healing. Furthermore, the SP-loaded SIS/PCLA group exhibited a lower macrophage count (2.9%) than did the PCLA (7.7%) and SIS/PCLA (3.4%) groups. It was thus confirmed that the use of SP-loaded SIS/PCLA sheet as a cell-free scaffold could effectively enhance wound healing through MSC recruitment.
10.1039/c9tb01532a
Combined effect of substance P and curcumin on cutaneous wound healing in diabetic rats.
Kant Vinay,Kumar Dinesh,Prasad Raju,Gopal Anu,Pathak Nitya N,Kumar Pawan,Tandan Surender K
The Journal of surgical research
BACKGROUND:Our earlier studies demonstrated that topically applied substance P (SP) or curcumin on excision skin wound accelerated the wound healing in streptozotocin-induced diabetic rats. In the present study, we aimed to evaluate the wound healing potential of combination of SP and curcumin in diabetic rats. MATERIALS AND METHODS:Open cutaneous excision wound was created on the back of each of the 60 diabetic rats. Wound-inflicted rats were equally divided into three groups namely, control, gel treated, and SP + curcumin treated. Normal saline, pluronic gel, and SP (0.5 × 10M) + curcumin (0.15%) were topically applied once daily for 19 d to these control, gel-treated, and SP + curcumin groups, respectively. RESULTS:SP + curcumin combination significantly accelerated wound closure and decreased messenger RNA expressions of tumor necrosis factor-alpha, interleukin-1beta, and matrix metalloproteinase-9, whereas the combination markedly increased the expressions of interleukin-10, vascular endothelial growth factor, transforming growth factor-beta1, hypoxia-inducible factor 1-alpha, stromal cell-derived factors-1alpha, heme oxygenase-1 and endothelial nitric oxide synthase, and activities of superoxide dismutase, catalase, and glutathione peroxidase in granulation-healing tissue, compared with control and gel-treated groups. In combination group, granulation tissue was better, as was evidenced by improved fibroblast proliferation, collagen deposition, microvessel density, growth-associated protein 43-positive nerve fibers, and thick regenerated epithelial layer. CONCLUSIONS:The combination of SP and curcumin accelerated wound healing in diabetic rats and both the drugs were compatible at the doses used in this study.
10.1016/j.jss.2017.01.011
Role of Substance P Neuropeptide in Inflammation, Wound Healing, and Tissue Homeostasis.
Suvas Susmit
Journal of immunology (Baltimore, Md. : 1950)
Substance P (SP) is an undecapeptide present in the CNS and the peripheral nervous system. SP released from the peripheral nerves exerts its biological and immunological activity via high-affinity neurokinin 1 receptor (NK1R). SP is also produced by immune cells and acts as an autocrine or paracrine fashion to regulate the function of immune cells. In addition to its proinflammatory role, SP and its metabolites in combination with insulin-like growth factor-1 are shown to promote the corneal epithelial wound healing. Recently, we showed an altered ocular surface homeostasis in unmanipulated NK1R mice, suggesting the role of SP-NK1R signaling in ocular surface homeostasis under steady-state. This review summarizes the immunobiology of SP and its effect on immune cells and immunity to microbial infection. In addition, the effect of SP in inflammation, wound healing, and corneal epithelial homeostasis in the eye is discussed.
10.4049/jimmunol.1601751
Substance P, a Neuropeptide, Promotes Wound Healing via Neurokinin-1 Receptor.
The international journal of lower extremity wounds
Substance P (SP), an endogenous neuropeptide, mediates intracellular signaling, mainly through a tachykinin receptor. The tachykinin receptors family consists of neurokinin-1 (NK-1), neurokinin-2 (NK-2), and neurokinin-3 receptors. Our previous studies on SP have shown its wound healing potentials. But the exact mechanism of wound healing by SP is not exactly known. In view of this, the present study was aimed at evaluating the in vitro wound healing effect of SP alone and in the presence of NK-1, NK-2, and both receptor antagonists. Scratch assay, transwell assay, and tumor growth factor-beta 1 (TGF-β1) assay were performed on buffalo fetal fibroblast culture. The cotreatment of fibroblast cultures with SP alone during the 24 h caused the significant proliferation and migrations of cells in both horizontal and vertical directions. The SP in the presence of spantide II (NK-1 antagonist) failed to stimulate this migration. The treatment of cells with SP in the presence of NK-2 antagonist treatment also showed a significant reduction of migration of cells with respect to SP treatment alone. The SP in the presence of both NK-1 and NK-2 antagonists failed to stimulate the horizontal migration of cells and most of the ineffectiveness of SP was observed in this combination. The TGF-β1 levels were significantly higher in the supernatants of cells that were exposed to SP alone. All other treatments have significantly lower TGF-β1 levels than SP alone treatment. It is concluded that different actions on fibroblast cells by SP were mainly mediated through the NK-1 receptor.
10.1177/15347346211004060
A Novel Substance P-Based Hydrogel for Increased Wound Healing Efficiency.
Kim Da Jung,Jang Ji Hae,Jang Song Sun,Lee Jungsun
Molecules (Basel, Switzerland)
The neuropeptide substance P (SP) is known to stimulate wound healing by regulating the production of relevant cytokines as well as cell proliferation and migration. However, the therapeutic application of SP is limited by its low stability under biological conditions and oxidation during purification, formulation, and storage. To address this problem, we developed a novel formulation of SP as an SP gel, and investigated its wound healing activity both in vitro and in vivo. SP in SP gel was stable at various temperatures for up to 4 weeks. In vitro, SP gel exhibited more potential as a candidate wound-healing agent than SP alone, as evidenced by the observed increases in the proliferation and migration of human epidermal keratinocytes and human dermal fibroblasts. In vivo experiments showed that SP gel treatment enhanced the healing of full-thickness wounds in mice as compared to SP alone. These results demonstrate the benefits of SP gel as a promising topical agent for wound treatment.
10.3390/molecules23092215
Gene expression of pro-inflammatory cytokines and neuropeptides in diabetic wound healing.
Pradhan Leena,Cai Xuemei,Wu Szuhuei,Andersen Nicholas D,Martin Michelle,Malek Junaid,Guthrie Patrick,Veves Aristidis,Logerfo Frank W
The Journal of surgical research
The interaction between neuropeptides and cytokines and its role in cutaneous wound healing is becoming evident. The goal of the present study is to investigate the impact of diabetes on peripheral cytokine and neuropeptide expression and its role in diabetic wound healing. To achieve this goal, the effect of diabetes on wound healing, along with the role of inflammatory cytokines such as interleukin-6 (IL-6) and interleukin-8 (IL-8) secreted in the wound microenvironment, and neuropeptides such as substance P (SP) and neuropeptide Y (NPY), secreted from peripheral nerves is monitored in non-diabetic and diabetic rabbits. Rabbits in the diabetic group received alloxan monohydrate (100mg/kg i.v.). Ten days after diabetic induction, four full thickness circular wounds were created in both ears using a 6mm punch biopsy. Wound healing was monitored over 10 d and gene expression of cytokines and neuropeptides was assessed in the wounds. Compared with the non-diabetic rabbits, wounds of diabetic rabbits heal significantly slower. Diabetic rabbits show significantly increased baseline gene expression of IL-6 and IL-8, their receptors, CXCR1, CXCR2, GP-130, and a decrease of prepro tachykinin-A (PP-TA), the precursor of SP, whereas the expression of prepro-NPY (PP-NPY), the precursor of NPY is not different. Similarly, baseline protein expression of CXCR1 is higher in diabetic rabbit skin. Post-injury, the increase over baseline gene expression of IL-6, IL-8, CXCR1, CXCR2, and GP-130 is significantly less in diabetic wounds compared with non-diabetic wounds. Although there is no difference in PP-TA gene expression between non-diabetic and diabetic rabbits post-injury, the gene expression of PP-NPY is reduced in diabetic rabbits. In conclusion, diabetes causes dysregulation in the neuropeptide expression in the skin along with a suppressed focused inflammatory response to injury. This suggests that the chronic inflammation in the skin of diabetic rabbits inhibits the acute inflammation much needed for wound healing.
10.1016/j.jss.2009.09.012
Influence of sensory neuropeptides on human cutaneous wound healing process.
Chéret J,Lebonvallet N,Buhé V,Carre J L,Misery L,Le Gall-Ianotto C
Journal of dermatological science
BACKGROUND:Close interactions exist between primary sensory neurons of the peripheral nervous system (PNS) and skin cells. The PNS may be implicated in the modulation of different skin functions as wound healing. OBJECTIVE:Study the influence of sensory neurons in human cutaneous wound healing. METHODS:We incubated injured human skin explants either with rat primary sensory neurons from dorsal root ganglia (DRG) or different neuropeptides (vasoactive intestinal peptide or VIP, calcitonin gene-related peptide or CGRP, substance P or SP) at various concentrations. Then we evaluated their effects on the proliferative and extracellular matrix (ECM) remodeling phases, dermal fibroblasts adhesion and differentiation into myofibroblasts. RESULTS:Thus, DRG and all studied neuromediators increased fibroblasts and keratinocytes proliferation and act on the expression ratio between collagen type I and type III in favor of collagen I, particularly between the 3rd and 7th day of culture. Furthermore, the enzymatic activities of matrix metalloprotesases (MMP-2 and MMP-9) were increased in the first days of wound healing process. Finally, the adhesion of human dermal fibroblasts and their differentiation into myofibroblasts were promoted after incubation with neuromediators. Interestingly, the most potent concentrations for each tested molecules, were the lowest concentrations, corresponding to physiological concentrations. CONCLUSION:Sensory neurons and their derived-neuropeptides are able to promote skin wound healing.
10.1016/j.jdermsci.2014.02.001
Neuropeptide Substance P Enhances Skin Wound Healing In Vitro and In Vivo under Hypoxia.
Kumar Suneel,Tan Yuying,Berthiaume Francois
Biomedicines
Pressure ulcers (PUs) or sores are a secondary complication of diabetic neuropathy and traumatic spinal cord injury (SCI). PUs tend to occur in soft tissues located around bony prominences and may heal slowly or not at all. A common mechanism underlying impaired healing of PUs may be dysfunction of the local neurovascular system including deficiency of essential neuropeptides, such as substance P (SP). Previous studies indicate that disturbance in cutaneous sensory innervation leads to a defect in all stages of wound healing, as is the case after SCI. It is hypothesized that nerve fibers enhance wound healing by promoting initial inflammation via the releasing of neuropeptides such as SP. Therefore, we investigated whether exogenous SP improves skin wound healing using in vitro and in vivo models. For in vitro studies, the effects of SP on keratinocyte proliferation and wound closure after a scratch injury were studied under normoxia (pO ~21%) or hypoxia (pO ~1%) and in presence of normal serum (10% /) or low serum (1% /) concentrations. Hypoxia and low serum both significantly slowed cell proliferation and wound closure. Under combined low serum and hypoxia, used to mimic the nutrient- and oxygen-poor environment of chronic wounds, SP (10 M) significantly enhanced cell proliferation and wound closure rate. For in vivo studies, two full-thickness excisional wounds were created with a 5 mm biopsy punch on the dorsum on either side of the midline of 15-week-old C57BL/6J male and female mice. Immediately, wounds were treated topically with one dose of 0.5 μg SP or PBS vehicle. The data suggest a beneficial role in wound closure and reepithelization, and thus enhanced wound healing, in male and female mice. Taken together, exogenously applied neuropeptide SP enhanced wound healing via cell proliferation and migration in vitro and in vivo. Thus, exogenous SP may be a useful strategy to explore further for treating PUs in SCI and diabetic patients.
10.3390/biomedicines9020222