Serum level of the autophagy biomarker Beclin-1 in patients with diabetic kidney disease.

Autophagy is a major cellular clearance mechanism that maintains cellular survival and homeostasis. Autophagy has a crucial role in the progression of diabetes and kidney diseases.

AIMS: To investigate serum concentrations of Beclin-1, a key regulator of autophagy, in patients with diabetic kidney disease (DKD).

METHODS: The study included 70 patients with type 2 diabetes and DKD (group 1; 35 patients with estimated glomerular filtration rate (eGFR) ≥ 30 ml/min/1.73 m2 and group 2; 35 patients with eGFR < 30 ml/min/1.73 m2 ) and 20 age- and sex-matched healthy subjects (group 3). Laboratory work up included; glycated hemoglobin (HbA1c), serum creatinine, eGFR using modification of diet in renal disease (MDRD) formula, urine albumin to creatinine ratio (ACR), and serum Beclin-1 measurement.

RESULTS: Patients with DKD had significantly lower Beclin-1 levels (2.38 ± 1.46 ng/mL) compared to control group (6.03 ± 1.94 ng/mL; P < 0.001). Moreover, serum Beclin-1 significantly decreased in group 2 (1.43 ± 0.83 ng/mL) compared to group 1 (3.36 ± 1.30 ng/mL; P < 0.001). In univariate analysis, the concentration of Beclin-1 correlated well with eGFR (r = 0.64, P < 0.001), ACR (r = -0.63, P < 0.001), and duration of diabetes (r = -0.43, P < 0.001) but didn't correlate with HbA1c (r = -0.17, P = 0.15). However, ACR was the only significant predictor of Beclin-1 level on performing multiple regression analysis (β = -0.40, P = 0.01).

CONCLUSION: Serum level of Beclin-1 is reduced in patients with DKD. Furthermore, its level is related to the stage of DKD and correlates with the degree of albuminuria.