We designed a method for measuring salivary adiponectin. In 188 healthy males, salivary adiponectin levels were measured using a commercial enzyme immunoassay kit for plasma with minor modifications. Intra- and inter-assay coefficients of variation for salivary adiponectin ranged from 0.6 to 4.9 and 1.1 to 9.8%, respectively. Salivary adiponectin levels ranged from 0.37 to 6.42 ng/ml, exceeding the kit's detection limit. For the over-43 age group, there was a significant correlation between plasma and salivary adiponectin levels (p<0.000001). These findings suggest the possibilities of salivary adiponectin as a marker of increased risk of non-insulin-dependent diabetes mellitus or cardiovascular disease.
BackgroundAdiponectin is an adipocyte-specific protein that plays a role in obesity, insulin resistant, lipid metabolism, and anti-inflammation. Hypoadiponectinemia may be associated with a higher risk for type 2 diabetes and cardiovascular disease. Some studies suggest that adiponectin levels are modulated by lifestyle factors, but little is known about the associations between lifestyle factors and plasma adiponectin levels in Japanese people. We therefore investigated the associations between lifestyle factors and plasma adiponectin levels in general Japanese men.MethodsThe subjects were 202 Japanese male workers who participated in an annual health check. They provided details about anthropometrical data, blood collection, their use of prescribed medication, and the clinical history of their families. They also completed a self-administered questionnaire about their lifestyles.ResultsSubjects with plasma adiponectin levels below 4.0 μg/ml had significantly lower levels of HDL cholesterol and higher levels of BMI, SBP, DBP, total cholesterol, FBG, and platelets than did subjects with higher adiponectin levels. In multiple logistic regression after multiple adjustment, a plasma adiponectin level below 4.0 μg/ml was significantly associated with smoking (odds ratio [OR] = 2.08, 95% confidence interval [CI] = 1.01–4.30), a daily diet rich in deep-yellow vegetables (OR = 0.25, 95% CI= 0.07–0.91), frequent eating out (OR = 2.45, 95% CI = 1.19–5.08), and physical exercise two or more times a week (OR = 0.21, 95% CI = 0.06–0.74).ConclusionOur findings show that adiponectin levels in general Japanese men are independently related to smoking, dietary factors, and physical exercise. We think that lifestyle habits might independently modulate adiponectin levels and that adiponectin might be the useful biomarker helping people to avoid developing type 2 diabetes and cardiovascular disease by modifying their lifestyles.
The maintenance of telomere integrity is essential for prolonged cell proliferation, and failure in this mechanism is a most consistent manifestation of cellular senescence. In this study, we investigated the role of telomere repeat binding factor (TRF1) in the proliferation of human fibroblasts. TRF1 expression is upregulated in a large variety of immortal human cells and supports de novo telomere formation in a dose-dependent manner. These observations suggest that the suppression of TRF1 might limit telomere maintenance and thus the life span of mortal cells. However, primary fibroblasts ectopically overexpressing TRF1 were unable to avoid senescence. On the other hand, exogenously expressed TRF1 in primary fibroblasts neither supported de novo telomere formation nor bound to the nuclear matrix as tightly as observed in immortal cells that show upregulated TRF1 expression. We present evidence suggesting that mortal human cells lack specific ligand(s) that anchor TRF1 to the nuclear matrix and that this contributes to their limited lifespan.
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