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    Effect of chronic aerobic exercise on cutaneous microcirculatory flow response to insulin iontophoresis and to ischemia in elderly males

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    The aim of this study was to assess whether chronic aerobic exercise can favourably influence the vascular activity of insulin in elderly subjects. We measured in arbitrary units (A. U.) the cutaneous blood flow basally and in response to iontophoresis of insulin, by the means of a Laser Doppler flowmeter, on the right arm of 10 elderly athletes (10 males, aged 65 +/- 6 years) and of 10 sex- and age-matched sedentary subjects. The cutaneous blood flow response to ischemia was also explored in the right leg of the same subjects by means of the same instrument. No significant differences in cutaneous arm and leg blood flow were observed basally between athletes and sedentary subjects (7.25 +/- 2.65 A. U. versus 6.35 +/- 4.04 A. U. and 9.74 +/- 5.11 A. U. versus 9.41 +/- 6.40 A. U., respectively). Cathodal iontophoresis (six poulses of 0.1 mA each for 20 s, with 40-s interval between stimulations) of regular insulin (0.1 ml Humulin R 100 IU/ml diluted 1/10 with 0.9 % saline) induced a significant increase of cutaneous blood flow in both groups (p < 0.01 in athletes, p < 0.01 in sedentary subjects). However the maximal cutaneous blood flow response to insulin was higher in athletes than in sedentary subjects (24.69 +/- 13.34 A. U. versus 14.33 +/- 7.73 A. U., respectively, p < 0.05) as well as the curve of the net blood flux response to insulin iontophoresis (% change from baseline in response to insulin minus % change from baseline in response to saline iontophoresis) (p < 0.001 ANOVA for repeated measures). After ischemia there was a significant increase of leg cutaneous blood flow in both groups (p < 0.001 in athletes and in sedentary subjects) with higher blood flow response in athletes than in sedentary subjects (38.18 +/- 17.08 A. U. versus 26.01 +/- 6.39 A. U., respectively, p < 0.05). The time reached from the release of ischemia to peak-flow was significantly longer in sedentary subjects than in athletes (43.5 +/- 28.5 s versus 20.0 +/- 9.3 s, p < 0.05, respectively). These results suggest that chronic aerobic exercise increases insulin vasodilatory activity and improves endothelial function in elderly subject

    Endothelium-dependent and endothelium-independent skin vasoreactivity in the elderly.

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    Background and aims: It was demonstrated that endothelium-dependent vasoreactivity, an aspect of endothelial functioning, is impaired in coronary and brachial arteries, and in skeletal muscle resistance vessels of elderly people. However, little data is available about the influence of aging per se on the endothelial function of the skin microcirculation. The aim of the present study was to evaluate the endothelial function and intrinsic vasodilatory capacity of the skin microcirculation in elderly people with a low atherosclerosis risk profile. Methods: Using laser Doppler flowmetry, we measured the cutaneous hyperemic responses following local iontophoresis delivery of an endothelium-dependent vasodilator, acetylcholine (ACh), and an endothelium-independent vasodilator, sodium nitroprusside (SNP), in 15 subjects older than 65 years and in 15 subjects younger than 50 years. Exclusion criteria were diabetes, hyperlipidemia, smoking, arterial hypertension and cardiovascular diseases. Results: Skin maximal hyperemic responses induced both by ACh and by SNP delivery did not differ between the younger and the older groups. Cutaneous blood flow progressively increased in response to the 8 ACh delivery steps, both in the older and younger groups; however, the dose-response curve following ACh delivery was significantly lower in the former (p<0.001). Conclusions: While these results should be viewed as preliminary due to the small sample size, they suggest that aging in itself is associated with a mild endothelium dysfunction in the skin microcirculation, whereas its overall vasodilatory capacity is preserved. (C) 2002, Editrice Kurtis
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