Effects of metformin on insulin sensitivity and islet beta cell secretion in obesity patients / 基础医学与临床

Objective To investigate the effects of metformin on insulin sensitivity and secretion in patients with obesity and insulin resistance. Methods This study enrolled 42 obesity patients with insulin resistance who were regularly followed-up in Peking Union Medical College Hospital from September 2012 to May 2016. They were divided into two groups according to their different status of glucose metabolism: normal glucose tolerance( NGT) and impaired glucose regulation( IGR) . Life style intervention and metformin were given to all these patients. The antropometric and metabolic data were collected before treatment, 3 and 6 months after treatment respectively. Results 42 patients, aged (23.6±6.5) years, including 11 males and 31 females were enrolled. 19 of them were NGT and 23 were IGR (8 of IGT and 15 of IFG) . Among all these patients, fasting insulin was significantly higher at 3 months after treatment(P＜0.05).The same results were shown in group-NGT(P＜0.05). Fasting insulin was significantly lower at 6 months after treatment than at baseline among all patients( P＜0.05) . HOMA-IR showed no significant difference between the baseline and 3 months after treatment, but significantly higher at baseline and 3 months after treatment than 6 months after therapy( P＜0.001) . HOMA-beta was significantly( P＜0.001) lower be-fore treatment and 6 months treatment the effect was more significant than 3 months after treatment among all pa-tients. HOMA-beta was significantly lower at baseline in group-IGR than at baseline in group-NGT ( P＜0.05) . Conclusions The effect of metformin on insulin secretion is earlier than that of improving the insulin sensitivity in patients with obesity and insulin resistance. Metformin is more likely to promote insulin secretion in patients with normal glucose tolerance than those with IGR within 3 months of intervention.

Analysis on plantar force parameters of gait under different simulated gravities / 医用生物力学

Objective To investigate the plantar force characteristics during human walking and running under different gravity environment. Methods Seven healthy male volunteers walked and ran in vertical position on a weight-loss suspension treadmill under simulated Mars gravity (1/3 G) and lunar gravity (1/6 G), and traditional earth gravity (1 G) respectively at three different velocities (3, 7 and 10 km/h). During the exercise, parameters such as stance phase, plantar force, and gait balance in gait cycle were analyzed by using the F-scan insole pressure distribution measurement system. Results At the same velocity during a gait cycle, the contact phase was significantly shorter with the decrease of gravity, but the swing phase was significantly longer (P0.05). The peak and average plantar force, force integrity were significantly reduced with the decrease of gravity. Under normal gravity, the increase of velocity could lead to an obvious increase in peak and average plantar force and an obvious decrease in force integrity. While under simulated lunar and Mars gravity, no significant changes were found in plantar force (P>0.05). Under the three gravities, the ratio of vertical impact was quite different in between (P<0.05), but no significant difference was found in the phase symmetry index. Conclusions As compared to normal gravity environment, parameters benefiting for skeleton and muscle function such as plantar force and contact phase were found to be much smaller under low gravity environment, indicating the necessity of considering these factors when designing countermeasures or exercise prescriptions for space flight so as to sustain the astronaut’s normal function of skeleton and muscle.

Effect of lentinan against immunosuppression of lymphocytes cultured in simulated microgravity environment / 中国实验血液学杂志

This study was aimed to evaluate the effect of lentinan on the immune function of splenic lymphocytes in rotary cell culture system (RCCS) microgravity environment. The splenic lymphocytes from mice were separated and cultured in the normal gravity and the microgravity environments. The cells were treated with lentinan solution (0, 10, 20 and 40 µg/ml). After incubated with lentinan for indicated times (24, 48 and 72 h), the cell proliferation, secretion of cytokine and the expression of cell surface markers were detected by MTT method, ELISA and flow cytometry respectively. The results indicated that lentinan of above mentioned concentrations did not obviously promote the lymphocyte proliferation, but increased the secretion of IL-2 and IFN-γ and enhanced the expression of lymphocyte surface markers CD4 and CD8 in microgravity environment. It is concluded that lentinan has the ability to enhance the lymphocyte immune function in microgravity environment.

Impact of potentially lethal ventricular arrhythmias on long-term outcome in patients with chronic heart failure / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Potentially lethal ventricular arrhythmias (PLVAs) occur frequently in survivors after acute myocardial infarction and are increasingly recognized in other forms of structural heart diseases. This study investigated the prevalence and prognostic significance of PLVAs in patients with chronic heart failure (CHF).</p><p><b>METHODS</b>Data concerning demographics, etiology of heart failure, NYHA functional class, biochemical variables, electrocardiographic and echocardiographic findings, and medical treatments were collected by reviewing hospital medical records from 1080 patients with NYHA II-IV and a left ventricular (LV) ejection fraction ≤ 45%. PLVAs were defined as multi-focal ventricular ectopy (> 30 beats/h on Holter monitoring), bursts of ventricular premature beats, and nonsustained ventricular tachycardia. All-cause mortality, sudden death, and rehospitalization due to worsening heart failure, or cardiac transplantation during 5-year follow-up after discharge were recorded.</p><p><b>RESULTS</b>The occurrence rate of PLVAs in CHF was 30.2%, and increased with age; 23.4% in patients < 45 years old, 27.8% in those between 45 - 65 years old, and 33.5% in patients > 65 years old (P = 0.033). Patients with PLVAs had larger LV size and lower ejection fraction (both P < 0.01) and higher all-cause mortality (P = 0.014) during 5-year follow-up than those without PLVAs. Age (OR 1.041, 95%CI 1.004 - 1.079, P = 0.03) and LV end-diastolic dimension (OR 1.068, 95%CI 1.013 - 1.126, P = 0.015) independently predicted the occurrence of PLVAs. And PLVA was an independent factor for all-cause mortality (RR 1.702, 95%CI 1.017 - 2.848, P = 0.031) and sudden death (RR 1.937, 95%CI 1.068 - 3.516, P = 0.030) in patients with CHF.</p><p><b>CONCLUSION</b>PLVAs are common and exert a negative impact on long-term clinical outcome in patients with CHF.</p>

Cordyceps sinensis enhances lymphocyte proliferation and CD markers expression in simulated microgravity environment / 中国实验血液学杂志

This study was aimed to explore the effect of cordyceps sinensis enhancing lymphocyte proliferation and surface CD marker expression in simulated microgravity environment. The splenic lymphocytes were separated from mice and cultured in the rotary cell culture system simulated microgravity environment. The cells were treated with different concentration of cordyceps sinensis solution (0, 6.25, 12.5, 25 and 50 µg/ml) for 24, 48 and 72 h respectively, then the cells were harvested, and analyzed for cell proliferation and the expression of cell surface markers (CD4 and CD8). The results showed that under simulated microgravity environment, the lymphocyte proliferation was inhibited. When the concentration of cordyceps sinensis was 25 or 50 µg/ml, the lymphocyte proliferation, CD4 and CD8 expressions all increased, but 50 µg/ml cordyceps sinensis could inhibit the proliferation ability with the time prolonging. It is concluded that the suitable concentration of cordyceps sinensis displayed the ability to enhance the lymphocyte proliferation and CD marker expression in simulated microgravity environment. These results may be valuable for screening drugs which can be potentially against immunosuppression under simulated microgravity.

Fatty acid synthase and hormone-sensitive lipase expression in liver are involved in zinc-alpha2-glycoprotein-induced body fat loss in obese mice / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To explore the effects of zinc-alpha2-glycoprotein (ZAG) on body weight and body fat in high-fat-diet (HFD)-induced obesity in mice and the possible mechanism.</p><p><b>METHODS</b>Thirty-six male mice were fed with standard food (SF) (n = 9) and HFD (n = 27), respectively. Five weeks later, 9 mice fed with HFD were subjected to ZAG expression plasmid DNA transfection by liposome transfection method, and another 9 mice to negative control plasmid transfection. Two weeks later, serum ZAG level in the mice was assayed by Western blot, and the effects of ZAG over-expression on body weight, body fat, serum biochemical indexes, and adipose tissue of obese mice were evaluated. The mRNA expressions of fatty acid synthase (FAS) and hormone-sensitive lipase (HSL) in liver tissue were determined by reverse transcription-polymerase chain reaction.</p><p><b>RESULTS</b>Serum ZAG level significantly lowered in simple HFD-fed mice in comparison to SF-fed mice (0.51 +/- 0.10 AU vs. 0.75 +/- 0.07 AU, P < 0.01). Further statistical analysis demonstrated that ZAG level was negatively correlated with body weight (r = -0.56, P < 0.001), epididymal fat mass (r = -0.67, P < 0.001), percentage of epididymal fat (r = -0.65, P < 0.001), and increased weight (r = -0.57, P < 0.001) in simple SF- and HFD-fed mice. ZAG over-expression in obese mice reduced body weight and the percentage of epididymal fat. Furthermore, FAS mRNA expression decreased (P < 0.01) and HSL mRNA expression increased (P < 0.001) in the liver in ZAG over-expressing mice.</p><p><b>CONCLUSIONS</b>ZAG is closely related to obesity. Serum ZAG level is inversely correlated with body weight and percentage of body fat. The action of ZAG is associated with reduced FAS expression and increased HSL expression in the liver of obese mice.</p>