Hyperbaric oxygen therapy increases telomere length and decreases immunosenescence in isolated blood cells: a prospective trial.
Hachmo Yafit,Hadanny Amir,Abu Hamed Ramzia,Daniel-Kotovsky Malka,Catalogna Merav,Fishlev Gregory,Lang Erez,Polak Nir,Doenyas Keren,Friedman Mony,Zemel Yonatan,Bechor Yair,Efrati Shai
INTRODUCTION:Aging is characterized by the progressive loss of physiological capacity. At the cellular level, two key hallmarks of the aging process include telomere length (TL) shortening and cellular senescence. Repeated intermittent hyperoxic exposures, using certain hyperbaric oxygen therapy (HBOT) protocols, can induce regenerative effects which normally occur during hypoxia. The aim of the current study was to evaluate whether HBOT affects TL and senescent cell concentrations in a normal, non-pathological, aging adult population. METHODS:Thirty-five healthy independently living adults, aged 64 and older, were enrolled to receive 60 daily HBOT exposures. Whole blood samples were collected at baseline, at the 30 and 60 session, and 1-2 weeks following the last HBOT session. Peripheral blood mononuclear cells (PBMCs) telomeres length and senescence were assessed. RESULTS:Telomeres length of T helper, T cytotoxic, natural killer and B cells increased significantly by over 20% following HBOT. The most significant change was noticed in B cells which increased at the 30 session, 60 session and post HBOT by 25.68%±40.42 (p=0.007), 29.39%±23.39 (p=0.0001) and 37.63%±52.73 (p=0.007), respectively. There was a significant decrease in the number of senescent T helpers by -37.30%±33.04 post-HBOT (P<0.0001). T-cytotoxic senescent cell percentages decreased significantly by -10.96%±12.59 (p=0.0004) post-HBOT. In conclusion, the study indicates that HBOT may induce significant senolytic effects including significantly increasing telomere length and clearance of senescent cells in the aging populations.
Hypoxia-inducible factor 2α regulates key neutrophil functions in humans, mice, and zebrafish.
Thompson A A Roger,Elks Philip M,Marriott Helen M,Eamsamarng Suttida,Higgins Kathryn R,Lewis Amy,Williams Lynne,Parmar Selina,Shaw Gary,McGrath Emmet E,Formenti Federico,Van Eeden Fredericus J,Kinnula Vuokko L,Pugh Christopher W,Sabroe Ian,Dockrell David H,Chilvers Edwin R,Robbins Peter A,Percy Melanie J,Simon M Celeste,Johnson Randall S,Renshaw Stephen A,Whyte Moira K B,Walmsley Sarah R
Neutrophil lifespan and function are regulated by hypoxia via components of the hypoxia inducible factor (HIF)/von Hippel Lindau/hydroxylase pathway, including specific roles for HIF-1α and prolyl hydroxylase-3. HIF-2α has both distinct and overlapping biological roles with HIF-1α and has not previously been studied in the context of neutrophil biology. We investigated the role of HIF-2α in regulating key neutrophil functions. Human and murine peripheral blood neutrophils expressed HIF-2α, with expression up-regulated by acute and chronic inflammatory stimuli and in disease-associated inflammatory neutrophil. HIF2A gain-of-function mutations resulted in a reduction in neutrophil apoptosis both ex vivo, through the study of patient cells, and in vivo in a zebrafish tail injury model. In contrast, HIF-2α-deficient murine inflammatory neutrophils displayed increased sensitivity to nitrosative stress induced apoptosis ex vivo and increased neutrophil apoptosis in vivo, resulting in a reduction in neutrophilic inflammation and reduced tissue injury. Expression of HIF-2α was temporally dissociated from HIF-1α in vivo and predominated in the resolution phase of inflammation. These data support a critical and selective role for HIF-2α in persistence of neutrophilic inflammation and provide a platform to dissect the therapeutic utility of targeting HIF-2α in chronic inflammatory diseases.
Transmigrating neutrophils shape the mucosal microenvironment through localized oxygen depletion to influence resolution of inflammation.
Campbell Eric L,Bruyninckx Walter J,Kelly Caleb J,Glover Louise E,McNamee Eóin N,Bowers Brittelle E,Bayless Amanda J,Scully Melanie,Saeedi Bejan J,Golden-Mason Lucy,Ehrentraut Stefan F,Curtis Valerie F,Burgess Adrianne,Garvey John F,Sorensen Amber,Nemenoff Raphael,Jedlicka Paul,Taylor Cormac T,Kominsky Douglas J,Colgan Sean P
Acute intestinal inflammation involves early accumulation of neutrophils (PMNs) followed by either resolution or progression to chronic inflammation. Based on recent evidence that mucosal metabolism influences disease outcomes, we hypothesized that transmigrating PMNs influence the transcriptional profile of the surrounding mucosa. Microarray studies revealed a cohort of hypoxia-responsive genes regulated by PMN-epithelial crosstalk. Transmigrating PMNs rapidly depleted microenvironmental O2 sufficiently to stabilize intestinal epithelial cell hypoxia-inducible factor (HIF). By utilizing HIF reporter mice in an acute colitis model, we investigated the relative contribution of PMNs and the respiratory burst to "inflammatory hypoxia" in vivo. CGD mice, lacking a respiratory burst, developed accentuated colitis compared to control, with exaggerated PMN infiltration and diminished inflammatory hypoxia. Finally, pharmacological HIF stabilization within the mucosa protected CGD mice from severe colitis. In conclusion, transcriptional imprinting by infiltrating neutrophils modulates the host response to inflammation, via localized O2 depletion, resulting in microenvironmental hypoxia and effective inflammatory resolution.
Anoxia and glucose supplementation preserve neutrophil viability and function.
Monceaux Valérie,Chiche-Lapierre Clarisse,Chaput Catherine,Witko-Sarsat Véronique,Prevost Marie-Christine,Taylor Cormac T,Ungeheuer Marie-Noelle,Sansonetti Philippe J,Marteyn Benoit S
Functional studies of human neutrophils and their transfusion for clinical purposes have been hampered by their short life span after isolation. Here, we demonstrate that neutrophil viability is maintained for 20 hours in culture media at 37°C under anoxic conditions with 3 mM glucose and 32 μg/mL dimethyloxalylglycine supplementation, as evidenced by stabilization of Mcl-1, proliferating cell nuclear antigen (PCNA), and pro-caspase-3. Notably, neutrophil morphology (nucleus shape and cell-surface markers) and functions (phagocytosis, degranulation, calcium release, chemotaxis, and reactive oxygen species production) were comparable to blood circulating neutrophils. The observed extension in neutrophil viability was reversed upon exposure to oxygen. Extending neutrophil life span allowed efficient transfection of plasmids (40% transfection efficiency) and short interfering RNA (interleukin-8, PCNA, and Bax), as a validation of effective and functional genetic manipulation of neutrophils both in vitro and in vivo. In vivo, transfusion of conditioned neutrophils in a neutropenic guinea pig model increased bacterial clearance of Shigella flexneri upon colonic infection, strongly suggesting that these conditioned neutrophils might be suitable for transfusion purposes. In summary, such conditioning of neutrophils in vitro should facilitate their study and offer new opportunities for genetic manipulation and therapeutic use.