Plasma adiponectin concentration is inversely associated with renal function. There is little literature on adiponectin levels and regulation by anti-hypertensive medication with an angiotensin II type 1 receptor blocker (ARB), especially in subjects with type 2 diabetes in different stages of chronic kidney disease (CKD).Methods
Eighty subjects with type 2 diabetic nephropathy were randomly divided into two groups: losarten group (n=41) and amlodipine group (n=39). Fasting blood was drawn to determine HbA1c, insulin and adiponectin levels. Insulin resistance was calculated using fasting glucose and insulin, expressed as HOMA-IR. For assessment of the relationship between adiponectin and other parameters, Pearson sample correlation coefficients were used. After stratification, ARB losartan (100 mg daily) was administered for a period of 6 months.Results
There is a positive association between adiponectin and proteinuria, fasting insulin levels and HOMA-IR in both CKD stage 1–2 and stage 3–4. Baseline adiponectin levels were not related to baseline estimated glomerular filtration rate (eGFR). At baseline, the adiponectin concentration was high in all observed subjects, and after 3 and 6 months of treatment with losartan, adiponectin levels decreased in the losartan group as compared with the amlodipine group (P < 0.01). Also fasting insulin and HOMA-IR decreased during the 6-month follow-up compared with the control group (P < 0.01).Conclusion
Our results demonstrate that serum adiponectin levels in type 2 diabetic nephropathy are strongly positively associated with fasting insulin levels and insulin resistance. Declines in fasting insulin and HOMA-IR by losartan are accompanied by decreased adiponectin levels, might offer potential protection in humans. The paradoxical phenomenon merits further ascertainment in future studies.