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Insulin signalling and resistance in patients with chronic heart failure
We investigated whether insulin resistance in patients with chronic heart failure (CHF) is associated with impaired insulin signalling in skeletal muscle and whether exercise training would lead to an improvement in insulin signalling, concomitant with enhanced insulin action. Fourteen men with CHF...
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Published in: | The Journal of physiology 2003-07, Vol.550 (1), p.305-315 |
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Main Authors: | , , , , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | We investigated whether insulin resistance in patients with chronic heart failure (CHF) is associated with impaired insulin
signalling in skeletal muscle and whether exercise training would lead to an improvement in insulin signalling, concomitant
with enhanced insulin action. Fourteen men with CHF due to idiopathic dilated cardiomyopathy, with mild-to-moderate limitation
of physical activity and a left-ventricular ejection fraction of less than 45 %, were studied before and after either a 5
month exercise training programme ( n = 7) or standard care ( n = 7). Seven healthy men participated as controls. Whole-body insulin-stimulated glucose uptake was determined by the euglycaemic
hyperinsulinaemic clamp technique and skeletal muscle biopsy samples were obtained before and after the insulin infusion for
insulin signalling measurements. Insulin-stimulated glucose uptake was 20 % lower in CHF patients versus healthy subjects. Physiological hyperinsulinaemia increased tyrosine phosphorylation of insulin receptor substrate (IRS)-1
by â2.5-fold, IRS-1-associated phosphatidylinositol 3-kinase (PI-3-kinase) activity by â2-fold and Akt (protein kinase B)
phosphorylation by â3-fold, with similar responses between healthy subjects and CHF patients. Insulin-mediated glucose uptake
was not altered in patients after standard care, whereas exercise training elicited a 25 % increase in glucose uptake. Neither
standard care nor exercise training altered insulin-stimulated tyrosine phosphorylation of IRS-1, IRS-1-associated PI-3-kinase
activity or Akt phosphorylation. In conclusion, the CHF patients demonstrated impaired insulin-stimulated glucose uptake,
despite normal signal transduction in skeletal muscle at the level of IRS-1, PI-3-kinase and Akt. Of clinical relevance is
the finding that exercise training improves glucose uptake. However, these changes in insulin action after exercise training
appear to be independent of enhanced insulin signalling at the level of IRS-1, PI-3-kinase or Akt. |
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ISSN: | 0022-3751 1469-7793 |
DOI: | 10.1113/jphysiol.2003.042648 |