Ageing impairs insulin-mediated vasodilatation but not forearm glucose uptake

• Published in: European journal of clinical investigation Vol. 31; no. 10; pp. 860 - 864
• Main Authors: Lind, L., Fugmann, A., Millgård, J., Berne, C., Lithell, H.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.10.2001; Blackwell; Blackwell Publishing Ltd
• Subjects: Adult; Aged; Aging - blood; Aging - physiology; Aging/blood/physiology; Biological and medical sciences; Blood flow; Blood Flow Velocity - physiology; Blood Glucose - metabolism; Blood vessels and receptors; elderly; Forearm; Fundamental and applied biological sciences. Psychology; glucose; Glucose Clamp Technique; Humans; insulin; Insulin - physiology; insulin resistance; Insulin Resistance - physiology; Male; MEDICIN; MEDICINE; Vasodilation - physiology; Vertebrates: cardiovascular system; Human; Healthy subject; Ageing; Glucose; Metabolism; Insulin; Biological activity; Vasodilation; Response variability; Extraction; Circulatory system; Endocrinology; Comparative study
• ISSN: 0014-2972; 1365-2362; 1365-2362
• DOI: 10.1046/j.1365-2362.2001.00882.x

Background It is unclear if insulin‐mediated vasodilatation is altered by ageing and if this affects insulin‐mediated glucose uptake. Material and methods A 2‐h euglycaemic hyperinsulinaemic clamp (56 mU m−2 min−1) was performed in 10 healthy, nonobese elderly men (70–75 years) and 13 young men (23–28 years). Forearm blood flow (FBF) was measured by venous occlusion plethysmography and forearm glucose uptake was calculated by arterial and venous serum glucose determinations in the forearm. Results Insulin induced an increase in FBF in the younger men (from 3·9 ± 1·1 SD to 5·9 ± 2·2 mL min−1 100 −1mL tissue, P < 0·001), but this insulin‐mediated vasodilatation was completely blunted in the elderly subjects. Glucose extraction during the clamp was significantly higher in the elderly subjects (1·2 ± 0·76 vs. 0·82 ± 0·37 mmol L−1 at 120 min, P < 0·01), resulting in a similar forearm glucose uptake in the two groups. On the other hand, whole‐body glucose uptake was significantly decreased in the elderly subjects (5·3 ± 1·8 vs. 8·0 ± 1·1 mg kg−1 min−1, P < 0·001). Conclusion The present study showed that the ability of insulin to induce vasodilatation is blunted in the forearm in healthy, nonobese elderly subjects. However, the elderly compensate for this impairment with an increased glucose extraction from arterial blood to maintain an unaltered forearm glucose uptake.