ABSTRACT
OBJECTIVE: Growth hormone and insulin-like growth factor-1 participate in post-myocardial infarction healing, but their relative importance is unclear. We compared the treatment effects of these agents on left ventricular remodelling. DESIGN: Wistar rats were randomised into a single dose of either growth hormone (0.5microg, n=29), or insulin-like growth factor-1 (0.5microg, n=27), delivered by direct intramyocardial punctures, and were compared with controls (n=30). Five minutes after treatment, myocardial infarction was generated by permanent ligation of the left coronary artery. Twenty-four hours post-ligation, serum levels of catecholamines were measured using radioimmunoassay and infarct size as well as infarct expansion index were calculated. The expression of genes related to extracellular matrix and angiogenesis was measured using polymerase chain reaction. RESULTS: Infarct expansion index was lower in growth hormone-treated rats (0.28+/-0.03, p=0.007) and in insulin-like growth factor-1-treated rats (0.35+/-0.03, p=0.044) compared to controls (0.51+/-0.06). Infarct size was significantly (p=0.0076) lower in growth hormone-treated rats (32.2+/-2.0%) and marginally (p=0.094) lower in insulin-like growth factor-1-treated rats (36.2+/-2.3%) compared to controls (42.0+/-2.7%). Survival rates were comparable in the three groups. Epinephrine was lower in the growth hormone group (2.8+/-0.2microg/l) compared to either controls (5.0+/-0.6microg/l, p=0.007), or to insulin-like growth factor-1-treated rats (6.3+/-0.6microg/l, p=0.0001). Collagen I and III expression in the infarct zone was higher in the growth hormone group compared to either the insulin-like growth factor-1 group or to controls. CONCLUSIONS: Both growth hormone and insulin-like-growth factor-1 decrease early infarct expansion, but growth hormone results in more favourable extracellular matrix remodelling and sympathetic activation.
Subject(s)
Growth Hormone/pharmacology , Insulin-Like Growth Factor I/pharmacology , Myocardial Infarction/pathology , Ventricular Remodeling/drug effects , Animals , Apoptosis/drug effects , Apoptosis/genetics , Catecholamines/blood , Coronary Occlusion/genetics , Coronary Occlusion/metabolism , Coronary Occlusion/pathology , Extracellular Matrix/drug effects , Female , Gene Expression Regulation/drug effects , Myocardial Infarction/genetics , Myocardial Infarction/metabolism , Myocardial Infarction/mortality , Neovascularization, Physiologic/drug effects , Neovascularization, Physiologic/genetics , Random Allocation , Rats , Rats, Wistar , Time Factors , Ventricular Remodeling/genetics , fas Receptor/metabolismABSTRACT
An epidemiological survey of idiopathic scoliosis derived by school screening in Greece has shown a three-fold rise in prevalence rate from 1% in 6-year-olds to more than 3% in 15-year-olds. Moderate curves (with a Cobb angle of 10 degrees to 19 degrees) are the most common curve magnitude encountered in both boys and girls. Typical curves (right thoracic, left lumbar, or right thoracic left lumbar double structural configurations) become relatively more prevalent with rising curve magnitude, while atypical curve patterns (left thoracic, right lumbar, or left thoracic right lumbar double structural configurations) reciprocally diminish. Growth is clearly an important environment in which curves progress and peak prevalence rates occur at the ages of 11 years and 13 years. Although it is not possible to prognosticate about the individual case, attention to these characteristics derived from epidemiological surveys is useful in assessing future curve behavior.
