Low molecular weight heparin may benefit nephrotic remission in steroid‑sensitive nephrotic syndrome via inhibiting elastase.

Low molecular weight heparin (LMWH) has a structure similar to heparan sulfate, which exerts anti‑inflammatory effects via inhibiting elastase (Ela) activity. Release of Ela along the glomerular capillary wall may induce glomerular injury and proteinuria. The present study aimed to investigate the influence of LMWH on steroid‑sensitive nephrotic syndrome (SSNS) and the potential underlying mechanism. A total of 40 SSNS patients and 20 healthy controls were recruited. SSNS patients were treated with LMWH and prednisone simultaneously (LMWH+pred group) or with prednisone alone (pred group). Proteinuria, urinary glycosaminoglycans (GAGs), serum Ela and urinary creatinine levels were measured. The nephrotic period of SSNS was 15.93±5.78 days. The nephrotic period of SSNS in LMWH+pred group was significantly reduced compared with the pred group (14.13±4.56 vs. 18.63±6.49 days; P<0.05). At the follow‑up of the SSNS patients, there was no statistically significant difference in number of relapses between the LMWH+pred and pred groups. Proteinuria (2.51±0.97 g/24 h), urinary GAG levels (4.92±0.87 mg/mmol creatinine) and serum Ela levels (77.64±10.99 ng/l) were significantly greater in the nephrotic period of SSNS compared with the remission period (0.107±0.026 g/24 h, 1.53±0.27 mg/mmol Cr and 41.92±7.81 ng/l, respectively) and the healthy control group (0.098±0.027 g/24 h, 1.40±0.26 mg/mmol creatinine and 38.43±9.83 ng/l, respectively; P<0.05). During the remission period, urinary GAG and serum Ela levels in the LMWH+pred group were significantly reduced compared with the pred group (P<0.05), whereas proteinuria did not differ between these groups (P>0.05). Positive correlations were revealed between urinary GAG excretion and proteinuria (r=0.877; P<0.05), proteinuria and serum Ela levels (r=0.844; P<0.05) and serum Ela levels and urinary GAG excretion (r=0.881; P<0.05). The results of the present study indicated that elevated serum Ela levels may induce proteinuria by degrading GAGs in the glomerular basement membrane in children with SSNS. LMWH may benefit nephrotic remission of SSNS via inhibiting Ela.