Age-related serum levels of insulin-like growth factor-I, -II and IGF-binding protein-3 following myocardial infarction.
Aging retards the repair process by decreasing hormone secretion from the somatotrophic axis, which plays a major role in tissue reconstruction after injury. The aim of this study was to determine the effect of aging on serum insulin-like growth factor-I (IGF-I), IGF-II and IGF-binding protein-3 (IGFBP-3) levels following myocardial infarction (MI). For four consecutive days, we monitored the variation of serum IGF-I, IGF-II and IGFBP-3 concentrations in 26 patients aged 19-71 years who were diagnosed with MI. Serum IGF-I, IGF-II and IGFBP-3 were measured daily by double antibody radioimmunoassay. Daily serum IGF-I concentrations showed a significant negative correlation with age (r = -0.528, P< 0.001). Total serum IGF-I was significantly (P = 0.002) higher in the younger age group (patients under 50 years) compared to the older group (50 years and over); 206 +/- 16 ng/ml vs 136 +/- 12 ng/ml. During this investigation, younger patients (under 50 years) showed no significant daily variations in IGF-I levels compared to older patients (50 years and over) who presented a significant decline (P = 0.012). Total serum IGF-II in both groups decreased significantly with time. Total serum IGFBP-3 in the younger age group was significantly higher (P = 0.046) than in the older age group (3.42 +/- 0.18 microgram/ml vs 2.95 +/- 0.13 microgram/ml). MI patients in both groups showed significantly lower IGF-I and IGF-II (IGFs) with higher IGFBP-3 compared to age- and sex-adjusted levels of normal adults (controls). The present results confirm that age and cardiac condition affect IGFs and IGFBP-3 levels. We are inclined to believe that older patients with a cardiac condition are less able to maintain their blood IGF-I levels during the recovery period compared to younger patients. Given the biological impact of IGF-I on regeneration, this could explain why older patients take longer to recover and heal poorly in comparison to younger patients.
Faculties of Nursing, University of Montreal, Quebec, Canada.
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I
Reeves
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Abribat
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Laramee
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Jasmin
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Brazeau
D000328:Adult; D000368:Aged; D000375:Aging; D000704:Analysis of Variance; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007335:Insulin-Like Growth Factor II / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000378:metabolism*; D011863:Radioimmunoassay; D015427:Reperfusion Injury / Q000097:blood; D013997:Time Factors
D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II