Leptin to adiponectin ratio - A surrogate biomarker for early detection of metabolic disturbances in obesity.
Larsen M A,Isaksen V T,Moen O S,Wilsgaard L,Remijn M,Paulssen E J,Florholmen J,Goll R
Nutrition, metabolism, and cardiovascular diseases : NMCD
AIM:To study if the leptin to adiponectin (L:A) ratio, can be a potential biomarker for postprandial triglyceride clearance, insulin resistance (IR) or leptin resistance (LR) in apparently healthy obese, and obese individuals with established metabolic disease. METHODS AND RESULTS:Fifty adult subjects with obesity (BMI ≥30); of which 36 metabolic healthy obese (MHO), and 14 metabolic dysregulated obese (MDO), with clinical and/or biochemical signs of metabolic disease were included. Seventeen healthy, normal weight subjects represented the control group. Postprandial triglyceride (TG) levels were measured in an 8 h oral fat tolerance test (OFTT). IR by HOMA-IR, L:A ratio and indirect LR were measured. In the MHO group, 71.4%, 69.4% and 86.1%, had delayed TG clearance, IR and LR, respectively; whereas in the MDO group this was detected in 85.7%, 71.4% and 91.7%, respectively. A combination of all three metabolic risk factors was found in 39.8% of the MHO and in 42.9% of the MDO patients. Receiver operating characteristics (ROC) analysis revealed that a cut-off value for the L:A ratio of >1.65 for the control group (PPV 1.0, NPV 0.91) and >3.65 for the obese subjects (PPV 0.86, NPV 0.48) predicted the delayed TG clearance with a good specificity and sensitivity. Detecting a combined risk with at least 2/3 metabolic risk factors, the ROC yielded the most suitable L:A ratio cut-off at >1.88. CONCLUSION:L:A ratio was able to detect early metabolic disturbances in obese individuals, and may be a potential useful clinical surrogate biomarker of metabolic disorders.
Protein biochip-based semiquantitative detection for plasma leptin.
Ye Lei,Hu Yuan,Xu Fei-Hong,Cai Cheng-Yun,Song Da-Wei,Xu Zhen-Shan,Du Wei-Dong
Proteomics. Clinical applications
PURPOSE:Plasma leptin is secreted from adipose tissues and plays pivotal roles in human physiological and pathological processes. Here, we aimed at conducting a protein biochip-based sandwich-like approach for detection of plasma leptin among healthy individuals, obesity, and diabetes patients. EXPERIMENTAL DESIGN:Totally, 96 plasma samples, including 45 healthy individuals with standard body mass index (BMI), 28 obesity and 23 diabetes patients, were recruited in the study. Plasma leptin was detected by a well-established protein biochip. Meanwhile an ELISA was also performed for assessment of the leptin detection by the protein biochip. RESULTS:We found that the plasma leptin level in the obesity and diabetes patients was significantly higher than that in healthy individuals with standard body mass index (p < 0.001). The limit detection concentration of leptin was as low as 0.006 μg/mL. The plasma leptin could be semiquantitatively detected by the protein biochip. The compatibility of the biochip-based detection approach seemed acceptable in comparison with the ELISA assay (R = 0.948). CONCLUSIONS:We provided a protein biochip-based approach for plasma detection. This approach would be a potential substitution for the ELISA assay.
Porous graphene-black phosphorus nanocomposite modified electrode for detection of leptin.
Cai Jinying,Gou Xiaodan,Sun Bolu,Li Wuyan,Li Dai,Liu Jinglong,Hu Fangdi,Li Yingdong
Biosensors & bioelectronics
Leptin is a vital biomarker of non-alcoholic fatty liver (NAFLD), and its evaluation of the concentration level in vivo is of great significance to NAFLD diagnosis. Therefore, it is pressing to develop a method for rapid and sensitive detection of leptin. This paper describes an environmentally friendly and label-free immunosensor based on porous graphene functionalized black phosphorus (PG-BP) composite to detect of leptin. The PG-BP was synthesized via strong coherent coupling between porous graphene (PG) surface plasmons and anisotropic black phosphorus (BP) localized surface plasmons, which made the electrochemical performance of PG and BP synergistic as well as increased the stability and conductive capability of BP material. The PG-BP modified electrodes was further prepared by gold nanoparticles, cysteamine, and glutaraldehyde in turn. Due to the cross-linking effect of glutaraldehyde, anti-leptin can be firmly fixed. These properties of the platform improved the conductive capability of the immunosensor and enhanced the load capacity of the proteins, thereby, the sensitivity of the immunosensor was significantly increased. Under the optimal conditions, the proposed immunosensor exhibited a wide linear range of 0.150-2500 pg/mL with a low detection limit of 0.036 pg/mL. The leptin immunosensor displayed excellent selectivity and anti-interference ability, which could be used for early screening and diagnosis of clinical NALFD.