Experimental gerontology
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Experimental gerontology · Jul 2014
The association between physical activity and reduced body fat lessens with age - results from a cross-sectional study in community-dwelling older adults.
The aim of this study was to describe the relationship between accelerometer-determined physical activity (PA) and adiposity in community-dwelling older adults. In addition, we were interested in comparing the extent of correlation between questionnaire and accelerometer determined PA. ⋯ Both the amount and intensity of PA, but not sedentary time, have an independent dose-response association with adiposity. The association is much stronger using objective assessment compared to questionnaire. The magnitude of these associations decrease with age suggesting that physical activity programmes may need to be modified with increasing age.
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Experimental gerontology · Jul 2014
Gene-gene interaction between CETP and APOE polymorphisms confers higher risk for hypertriglyceridemia in oldest-old Chinese women.
The knowledge of dyslipidemia and its genetic contributors in oldest-old subjects is limited; in addition, the majority of oldest-old subjects are females. Evidence has accumulated that multiple genetic factors play important roles in determining susceptibility to dyslipidemia and extended life span. Cholesterol ester transfer protein (CETP) and apolipoprotein E (APOE) are two plausible candidate genes for human longevity owing to their functionally related modulation of circulating lipid homeostasis; however, few studies have considered their interplay. ⋯ The stratification test, multivariable-adjusted logistic regression, and nonparametric MDR analysis all suggested a significant CETP*APOE interaction associated with hTG. The unadjusted odds for hTG were more than 4-fold in subjects with CETP*V and APOE*4 than those without either (OR=4.36, P<0.001). These results provide evidence of strong independent associations between hTG and CETP*V in oldest-old Chinese females, and APOE*4, as an independently non-significant variant, might interact with CETP*V resulting in an increased risk for hTG.
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Experimental gerontology · Jul 2014
Nano-structural, compositional and micro-architectural signs of cortical bone fragility at the superolateral femoral neck in elderly hip fracture patients vs. healthy aged controls.
To unravel the origins of decreased bone strength in the superolateral femoral neck, we assessed bone structural features across multiple length scales at this cortical fracture initiating region in postmenopausal women with hip fracture and in aged-matched controls. Our combined methodological approach encompassed atomic force microscopy (AFM) characterization of cortical bone nano-structure, assessment of mineral content/distribution via quantitative backscattered electron imaging (qBEI), measurement of bone material properties by reference point indentation, as well as evaluation of cortical micro-architecture and osteocyte lacunar density. Our findings revealed a wide range of differences between the fracture group and the controls, suggesting a number of detrimental changes at various levels of cortical bone hierarchical organization that may render bone fragile. ⋯ Fracture cases showed nearly 35% higher cortical porosity and showed significantly reduced osteocyte lacunar density compared to controls (226±27 vs. 247±32#/mm(2), p=0.05). Along with increased crystal size, a shift towards higher mineralization and a tendency to increased cortical porosity and reduced osteocyte lacunar number delineate that cortical bone of the superolateral femoral neck bears distinct signs of fragility at various levels of its structural organization. These results contribute to the understanding of hierarchical bone structure changes in age-related fragility.
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Experimental gerontology · Jul 2014
Cannabinoid receptor-dependent metabolism of 2-arachidonoylglycerol during aging.
2-Arachidonoylglycerol (2-AG) is one of the principal endocannabinoids involved in the protection against neurodegenerative processes. Cannabinoids primarily interact with the seven-segment transmembrane cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2), both of which are expressed in the central nervous system (CNS). The level of 2-AG is controlled through key enzymes responsible for its synthesis or degradation. ⋯ To this end, both CB1 and CB2 receptor expression and the enzymatic activities (diacylglycerol lipase (DAGL), lysophosphatidate phosphohydrolase (LPAase) and monoacylglycerol lipase (MAGL)) involved in 2-AG metabolism were analyzed in the presence of cannabinoid receptor (CBR) agonists (WIN and JWH) and/or antagonists (SR1 and SR2) in synaptosomes from adult and aged rat cerebral cortex (CC). Our results demonstrate that: (a) aging decreases the expression of both CBRs; (b) LPAase inhibition, due to the individual action of SR1 or SR2, is reverted in the presence of both antagonists together; (c) LPAase activity is regulated mainly by the CB1 receptor in adult and in aged synaptosomes while the CB2 receptor acquires importance when CB1 is blocked; (d) modulation via CBRs of DAGL and MAGL by both antagonists occurs only in aged synaptosomes, stimulating DAGL and inhibiting MAGL activities; (e) only DAGL stimulation is reverted by WIN. Taken together, the results of the present study show that CB1 and/or CB2 receptor antagonists trigger a significant modulation of 2-AG metabolism, underlining their relevance as therapeutic strategy for controlling endocannabinoid levels in physiological aging.