Is there any relation between hyperinsulinemia, insulin resistance and colorectal lesions in patients with acromegaly?

INTRODUCTION: Pathogenesis of colonic lesions in patients with acromegaly remains still unclear. There are suggestions that apart from somatotropin axis hormones (GH and IGF-1), other agents also take part in this process. Molecular and animal studies indicate a vital role of hyperinsulinemia in development of colorectal neoplasms.

AIM OF THE STUDY: To evaluate a relation between insulin level, insulin resistance and its anthropometric markers and colorectal lesions in patients with acromegaly.

MATERIAL AND METHODS: The study consisted of 40 patients with active, newly diagnosed acromegaly; 24 women and 16 men aged from 24 to 77 years (mean age 50.1, SD+/-12.1). The analysis included the results of somatotropin axis function (GH and IGF-1 level), carbohydrate metabolism assessment (fasting serum glucose and insulin levels, oral glucose tolerance test, HOMA-IR for insulin resistance), the results of anthropometric measurement (BMI, WHR) and colonoscopy.

RESULTS: Colon pathologies (60 polyps and 2 flat lesions) were discovered in 19 (47.5%) patients with acromegaly, 8 of them had multiple polyps. Hyperplastic polyps were revealed in 11 (27.5%), while adenomas in 8 (20%) acromegalics. Patients with colorectal lesions were found to have higher WHR then subjects with normal colon (p=0.033). Positive correlation between the number of hyperplastic polyps in the patients with multiple changes in the colon and IGF-1 (p=0.025), insulin level (p=0.005) and HOMA-IR (p=0.001) was found. Multiple adenomas correlated positively with insulin level (p=0.007), HOMA-IR (p=0.006) and BMI (p=0.015).

CONCLUSIONS: The study results show a relation between hyperinsulinemia, insulin resistance and colon pathologies in acromegaly. Fasting insulin level and HOMA-IR correlate positively with the number of hyperplastic polyps and adenomas in acromegalic patients with multiply colorectal lesions.