Objective: Sarcopenia in older adults is closely related to vitamin D deficiency and reduced levels of physical activity, but little has been reported on the interaction between physical activity and the positive effects of vitamin D. The purpose of this study was to explore the interactive effect of vitamin D and physical activity on muscle mass and function through animal experiments and population surveys.Methods: Male 4‐week‐old C57BL/6J mice were fed different purified diets: a vitamin D‐deficient diet (with increased calcium and phosphorus to prevent the effects of abnormal mineral levels on muscle) or a 1,25‐dihydroxyvitamin D3 (1,25D)‐supplemented diet. After 24 weeks on the assigned diets, the mice were immobilized. The level of skeletal muscle atrophy in the mice was determined by grip strength, gastrocnemius (GA) muscle mass and muscle fiber cross‐sectional area (CSA); additionally, the protein expression levels of FOXO3a and the E3 ubiquitin ligases MuRF1 and MAFbx were detected. A cross‐sectional study included data from 4139 older adults (64.9% women, 67.9 ± 6.7 years) as part of a survey in Shenyang, Northeast China. The associations of serum 25(OH)D3 and physical activity with timed up and go test (TUG) performance, handgrip strength, calf circumference, and body muscle mass were assessed by a linear regression analysis that was adjusted for covariates.Results: In activity‐limited mice, vitamin D deficiency accelerated the decrease in GA muscle weight, muscle fiber CSA, and grip strength and increased the protein expression of MuRF1, MAFbx, and FOXO3a (all P < 0.05). In addition, 1,25D supplementation may inhibit the grip‐strength reduction induced by limited activity (P = 0.069). Serum 25(OH)D3 and physical activity were linearly related to TUG time (P < 0.001) and handgrip strength (P < 0.05) after adjustment for sex, age, body mass index (BMI), education level, smoking status, and serum calcium level. Serum 25(OH)D3 and physical activity had interactive effects on TUG (P < 0.001) and handgrip strength (P < 0.05) but not calf circumference or body muscle mass in older adults.Conclusions: The effect of vitamin D on muscle strength and physical performance depends on physical activity level in the elderly. It is recommended that older adults strive to avoid both physical inactivity and vitamin D deficiency. Because physical inactivity and vitamin D deficiency may exacerbate muscle atrophy, the biological mechanism may involve synergistic effects of vitamin D and physical activity on the promotion of muscle protein ubiquitination and degradation.
Risk Factors for Sarcopenia in the Elderly with Type 2 Diabetes Mellitus and the Effect of Metformin: Aims. Sarcopenia is a common condition in older individuals, especially in the elderly with type 2 diabetes mellitus (T2DM). The aim of the present study was to examine the risk factors for sarcopenia in elderly individuals with T2DM and the effects of metformin. Methods. A total of 1732 elderly with T2DM were recruited to this cross-sectional observational study, and we analyzed the data using logistic regression analyses. Skeletal muscle mass, grip strength, and usual gait speed were measured to diagnose sarcopenia according to the criteria of the Asian Working Group for Sarcopenia, combined with expert consensus on sarcopenia in China. Results. The overall prevalence of sarcopenia was 10.37% of the participants. In the multivariate analysis, sex, age, educational level, and BMI were risk factors for sarcopenia, with women more likely to develop sarcopenia relative to men ( , 95% –4.371; ). We observed that sarcopenia increased with age and decreased with increasing BMI and educational level ( ). Participants who took metformin alone or combined with other drugs exhibited a lower risk for sarcopenia than those who took no medication ( , 95% –0.904 and , 95% –0.702, respectively; ). Conclusions. We showed that being female and at an older age, lower educational level, and lower BMI were risk factors for sarcopenia in elderly T2DM and that metformin acted as a protective agent against sarcopenia in these patients.
At present, only a few studies have focused on the risk factors for depression in elderly diabetic patients, and there is little evidence for the effect of metformin in depressed elderly patients with diabetes than on its effect on blood glucose. The aim of the current work was to study the risk factors for depression in elderly diabetic patients and to ascertain the effects of metformin on the depressive state. We initiated a 1:4 matched case–control study. The case group comprised 110 elderly diabetic patients with depression from nine communities in Shenyang in 2017. The control group comprised 440 non-depressed elderly diabetic patients from the same communities, which were matched by gender and age (± 2 years of age) with the case group. Depression was measured using the Geriatric Depression Scale-15, and we performed matched univariate and multivariate logistic regression analyses. In the multivariate analysis, overweight status, poor physical capabilities and low activity level, and the presence of more than two additional illnesses were risk factors for depression in elderly patients with diabetes. For these risk factors, the adjusted ORs (all P < 0.05) were as follows: an adjusted OR of 2.031 and 95% CI of 1.180–3.495; an adjusted OR of 2.342 and 95% CI of 1.465–3.743; and an adjusted OR of 5.350 and 95% CI of 2.222–12.883, respectively. Patients taking metformin had a lower risk of depression than those taking no medication, with an adjusted OR of 0.567 and 95% CI of 0.323–0.997 (P < 0.05). Overweight status, poor physical capabilities and low activity level, and the presence of more than two additional illnesses were risk factors for depression in elderly diabetic patients, and metformin was a protective factor against depression in elderly diabetic patients.
1 September 2014 in Journal of Cardiovascular Pharmacology
Scutellarin inhibits hypoxia-induced and moderately high glucose–induced proliferation and vascular endothelial growth factor (VEGF) expression in human retinal endothelial cells (HRECs); thus, it could be a potential therapy for diabetic retinopathy. However, how scutellarin inhibits VEGF is unknown. In our study, HRECs were treated with high glucose and/or hypoxia-mimetic agent cobalt chloride to stimulate cell proliferation, migration, and angiogenesis, and the effects of scutellarin on these processes were analyzed through cell viability assay, Transwell migration assay and endothelial tube formation assay, respectively. The inhibition of angiogenic factor VEGF by scutellarin was confirmed by reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay. The mechanisms for VEGF inhibition were examined by luciferase reporter assay, Western blot, immunoprecipitation, and biochemical assays. We found that scutellarin not only concentration-dependently inhibited cell proliferation, migration, and tube formation in HRECs but also decreased their production of VEGF. The reduction of VEGF was due to increased ubiquitination and degradation of hypoxia-inducible factor (HIF)-1α by scutellarin. Furthermore, scutellarin impaired the interaction of HIF-1α with p300, which further decreased the transcriptional activity of HIF-1α. As an inducer of HIF-1α, oxidative stress was attenuated by scutellarin. Our data demonstrate that scutellarin exhibits an antiangiogenic effect via inhibition of oxidative stress, enhancement of HIF-1α degradation, and reduction of VEGF secretion.
China and the world are facing severe population aging and an increasing burden of age-related diseases. Aging of the brain causes major age-related brain diseases, such as neurodegenerative diseases and stroke. Identifying biomarkers for the effective assessment of brain aging and establishing a brain aging assessment system could facilitate the development of brain aging intervention strategies and the effective prevention and treatment of aging-related brain diseases. Thus, experts from the Aging Biomarker Consortium (ABC) have combined the latest research results and practical experience to recommend brain aging biomarkers and form an expert consensus, aiming to provide a basis for assessing the degree of brain aging and conducting brain-aging-related research with the ultimate goal of improving the brain health of elderly individuals in both China and the world.
1 October 2010 in American Journal of Physiology-Endocrinology and Metabolism
Excessive accumulation of lipids in macrophages results in formation of foam cells and is a hallmark of atherosclerosis. The PAT family of proteins has been implicated in this process, but details of their involvement in foam cell formation have not been fully elucidated. One of dominant members of the PAT proteins, perilipin 3 (TIP47), is likely to be involved in such a regulatory mechanism. In this study, we demonstrated that the Toll-like receptor 9 (TLR9)-mediated pathway stimulates perilipin 3 expression and accumulation of lipids, especially triglycerides, in macrophages. Oligodeoxynucleotide (ODN) 1826, a ligand of TLR9, significantly enhanced perilipin 3 expression in RAW264.7 cells, and chloroquine, a TLR9 inhibitor, almost completely inhibited ODN1826-induced perilipin 3 expression. The inhibitors of c-jun NH2-terminal kinase and PI 3-kinase suppressed the level of perilipin 3 mRNA induced by ODN1826. ODN1826 induced the expression of IL-1α and IFNβ, both of which increased perilipin 3 expression. Antibodies against these cytokines suppressed the ODN1826-induced perilipin 3 mRNA levels. These results suggest that the expression of perilipin 3 in macrophages is in part regulated through the TLR9-mediated mechanism. Furthermore, ODN1826 increased intracellular lipid accumulation in the presence of oxLDL, which was reduced by perilipin 3 siRNA. Perilipin 3 expression was not stimulated by oxLDL. Depletion of perilipin 3 by siRNA specifically reduced triglyceride content in the cells but not cholesterol content, indicating that perilipin 3 is involved mainly in triglyceride accumulation. In conclusion, the TLR9-mediated pathway facilitates foam cell formation in part through increased expression of perilipin 3.