Relationship between insulin-like growth factor-1 system and exercise tolerance in patients with intermittent...

Insulin-like growth factor-1 (IGF-1) plays an important role in exercise physiology. We aimed the present study at assessing whether IGF-1 system and its changes with exercise are related to walking capacity in intermittent claudication (IC).

In 45 IC patients, blood samples for the measurement of IGF-1, IGF binding protein-3 (IGFBP-3), and acid labile subunit (ALS) were taken at rest and immediately after a treadmill exercise performed until initial claudication distance (ICD), i.e. until the occurrence of claudication pain in the affected limb. Control group consisted of 45 age- and sex-matched subjects without previous myocardial infarction or stroke.

When IC patients were divided into two groups according to ICD value, ANOVA showed significant group differences for IGFBP-3 and ALS. Indeed, resting levels of IGFBP-3 were 3537+/-109 microg/L in controls, moderately lower (3399+/-204 microg/L) in IC patients with ICD >or= median, and markedly lower (2580+/-196 microg/L) in those with ICD

Impaired IGF-1 system is implicated in the complex mechanism responsible for reduced exercise tolerance in IC. Furthermore, this finding suggests that affected individuals could represent a target population for interventions to rise IGF-1 levels.