Effect of Aging on Glucose Homeostasis

Szoke, Ervin; Shrayyef, Muhammad; Messing, Susan; Woerle, Hans J.; Haeften, Timon W. van; Meyer, Christian; Mitrakou, Asimina; Pimenta, W P; Gerich, John E.

doi:10.2337/dc07-1443

Cited by 187 publications

(109 citation statements)

References 34 publications

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“…Although decreased insulin sensitivity is reported to occur with age, we found that both hepatic and peripheral insulin sensitivity were similar in YS and OS subjects. While the absence of age-related declines in insulin sensitivity is in contrast with numerous previous reports (4,21,30,31), our results are consistent with a growing body of literature indicating that adiposity and physical activity levels, rather than chronological age, are primary determinants of age-related declines in insulin sensitivity (32)(33)(34)(35)(36). In support of this notion, we find that fat mass, abdominal adiposity, and BMI were significant predictors of R d during the clamp.…”

Section: Nrf1supporting

confidence: 89%

Endurance Exercise as a Countermeasure for Aging

et al. 2008

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OBJECTIVE-We determined whether reduced insulin sensitivity, mitochondrial dysfunction, and other age-related dysfunctions are inevitable consequences of aging or secondary to physical inactivity.RESEARCH DESIGN AND METHODS-Insulin sensitivity was measured by hyperinsulinemic-euglycemic clamp and ATP production in mitochondria isolated from vastus lateralis biopsies of 42 healthy sedentary and endurance-trained young (18 -30 years old) and older (59 -76 years old) subjects. Expression of proteins involved in fuel metabolism was measured by mass spectrometry. Citrate synthase activity, mitochondrial DNA (mtDNA) abundance, and expression of nuclear-encoded transcription factors for mitochondrial biogenesis were measured. SIRT3, a mitochondrial sirtuin linked to lifespan-enhancing effects of caloric restriction, was measured by immunoblot.RESULTS-Insulin-induced glucose disposal and suppression of endogenous glucose production were higher in the trained young and older subjects, but no age effect was noted. Age-related decline in mitochondrial oxidative capacity was absent in endurance-trained individuals. Although endurance-trained individuals exhibited higher expression of mitochondrial proteins, mtDNA, and mitochondrial transcription factors, there were persisting effects of age. SIRT3 expression was lower with age in sedentary but equally elevated regardless of age in endurance-trained individuals.CONCLUSIONS-The results demonstrate that reduced insulin sensitivity is likely related to changes in adiposity and to physical inactivity rather than being an inevitable consequence of aging. The results also show that regular endurance exercise partly normalizes age-related mitochondrial dysfunction, although there are persisting effects of age on mtDNA abundance and expression of nuclear transcription factors and mitochondrial protein. Furthermore, exercise may promote longevity through pathways common to effects of caloric restriction. Diabetes 57: 2933-2942, 2008 R educed insulin sensitivity is a common factor in the metabolic syndrome, a cluster of clinical conditions that shows increased risk with age (1-3). Mitochondrial dysfunction is also prevalent in the elderly (4,5), with reductions in mitochondrial enzyme activities (6), protein synthesis (7) and expression (5), and DNA (mtDNA) abundance (5,8). A close association between insulin sensitivity and muscle mitochondrial function has been reported in aging (4,5), type 2 diabetes (9), and obesity (10) as well as in offspring of type 2 diabetic individuals (11), prompting a hypothesis that either reduced insulin sensitivity results from muscle mitochondrial dysfunction (4,11) or vice versa (5,12).Endurance exercise increases insulin sensitivity (13,14) and mitochondrial enzyme activities (15,16). Short-term and longitudinal studies have documented that older populations respond favorably to endurance exercise but that there are persisting age effects that cannot be eliminated by short-term exercise programs (8,17). For practical reasons, most training studies ar...

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Section: Nrf1supporting

confidence: 89%

Endurance Exercise as a Countermeasure for Aging

et al. 2008

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“…Decrease in beta cell proliferation capacity and enhanced sensitivity to apoptosis are the states related with aging (Maedler et al, 2006). A study by Szoke et al (2008) showed that the first and second phase of insulin secretion normally decreases at the rate of approximately 0.7% per year with aging, this decrease in cell function is accelerated about two-fold in people with impaired glucose tolerance. But aging per se has no effect on insulin sensitivity independent of change in body composition.…”

Section: Age and Type 2 Diabetes Mellitusmentioning

confidence: 99%

Age is an Important Risk Factor for Type 2 Diabetes Mellitus and Cardiovascular Diseases

Suastika¹,

Dwipayana²,

Semadi³

et al. 2012

Glucose Tolerance

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“…Similarly, a positive correlation of fasting plasma glucose (FPG) with age has been reported from some studies [5,6] but not in others [7,8]. The ageing of populations may further increase the burden of type 2 diabetes and pre-diabetes [impaired fasting glucose (IFG)/IGT] on health care systems worldwide [9]. Knowledge of the impact of age on IR together with β-cell function and glucose metabolism may have clinical implications in intervention and management of pre-diabetes and diabetes in elderly populations.…”

Section: Introductionmentioning

confidence: 99%