Urinary adiponectin excretion rises with increasing albuminuria in type 1 diabetes

Aim Urinary adiponectin (u-adiponectin) excretion has been suggested to reflect early glomerular damage. Inspired by this, we studied the levels of u-adiponectin in type 1 diabetic patients with different levels of urinary albumin excretion (UAE). Methods U-adiponectin was analysed by ELISA in type 1 diabetic patients: Fifty-eight with normoalbuminuria (<30mg albumin/24h), 43 with persistent microalbuminuria (30–300mg/24h) and 44 with persistent macroalbuminuria (>300mg/24h). For comparison, a control group of 55 healthy individuals was included. Results U-adiponectin increased with increasing levels of UAE (p<0.01). U-adiponectin median (interquartile range): Normoalbuminuria 0.38 (0.14–1.31), microalbuminuria 1.12 (0.20–2.68), macroalbuminuria 9.20 (1.10–23.35) and controls 0.09 (0.06–0.24) μg/g creatinine. Levels were unrelated to sex, age, cholesterol, diastolic BP and BMI. U-adiponectin was weakly associated with increasing systolic BP and HbA1c (r2<0.1, p<0.05), but strongly related to increasing UAE (r2=0.57, p<0.001) and decreasing eGFR (r2=0.26, p<0.001). The relationship between UAE and u-adiponectin was significant in all groups and independent of eGFR, BMI, BP and HbA1c. Furthermore, u-adiponectin was associated with markers of tubular damage (p<0.01). Conclusion U-adiponectin rises with increasing levels of UAE in patients with type 1 diabetes. This is in accordance with the hypothesis that loss of adiponectin may reflect glomerular and/or tubular damage.