The change of insulin-like growth factor-1 in diabetic patientswith neuropathy

OBJECTIVE: To evaluate the possible relationship between insulin-like growth factor-1 (IGF-1) and diabetic neuropathy (DNP). METHODS: Sixty-nine patients with Type 2 non-insulin-dependent diabetes (54 with peripheral neuropathy and 15 without neuropathy) were observed. Normal controls were 34 non-diabetic persons. Diabetic peripheral neuropathy diagnosis was carried out taking into account results of NS, ND, NC and AF. After an overnight fast, blood was taken for IGF-1, glucose, hemoglobin Alc, C-peptide, and insulin. Plasma IGF-1 was measured by radioimmunoassay (RIA) method. RESULTS: The neuropathic group had significantly lower levels for IGF-1 (86.43 ng/ml +/- 45.18 ng/ml) compared to normal controls (119.68 ng/ml +/- 89.42 ng/ml) (P < 0.05), and to diabetic patients without neuropathy (113.75 ng/ml +/- 66.58 ng/ml) (P < 0.05). No significant difference was found between diabetic non-neuropathic group and normal control subjects (P < 0.05). In diabetic subjects there was a positive correlation (gamma = 0.27, P < 0.05) between IGF-1 and beat to variation in heart rate. There were negative correlation between IGF-1 and postprandial blood glucose (gamma = -0.3, P < 0.05), and aspartic acid translocase (gamma = -0.27, P < 0.05). CONCLUSION: In diabetic patients with peripheral neuropathy there are abnormalities of IGF-1 that may contribute to the pathogeneses of diabetic neuropathy.