Sulodexide ameliorates early but not late kidney disease in models of radiation nephropathy and diabetic nephropathy

Abstract

Background: Sulodexide is a glycosaminoglycan with anticoagulant and antithrombotic activities. Although sulodexide reduced albuminuria in patients with type 1 and type 2 diabetes, long-term effects on chronic renal injury are not established. We investigated sulodexide effects and mechanisms in a rat radiation nephropathy model and in the db/db mouse model of diabetic kidney disease.

Methods: Sprague-Dawley rats received kidney radiation and were treated as follows: 15 mg/kg/day sulodexide s.c., 6 day/week (SUL) or no treatment (CONT). Subsets of animals were sacrificed after 8 weeks and 12 weeks. Blood pressure, serum creatinine, creatinine clearance (CrCl) and urinary protein excretion were measured every 4 weeks. Sclerosis and plasminogen activator inhibitor-1 (PAI-1) expression were assessed at 8 and 12 weeks, and collagen I, total collagen content and phospho-smad-2 expressions were determined at 12 weeks. Twelve-week-old db/db mice received sulodexide as above or vehicle. Albuminuria and CrCl were assessed at intervals till sacrifice at week 9 with assessment of urinary transforming growth factor-beta (TGF-beta) and glomerular lesions.

Results: Blood pressure, serum creatinine and CrCl were not different in radiation rat CONT vs SUL at any time. Proteinuria was significantly lower in SUL compared to CONT at 4 and 8 weeks but not at 12 weeks. Sclerosis and PAI-1 expression trended lower in SUL vs CONT at 8 weeks. There was no difference between the groups in sclerosis, collagen I mRNA, total collagen content or PAI-1 expression at 12 weeks. Phospho-smad 2 expression was significantly decreased in SUL compared to CONT at 12 weeks. Db/db mice with or without SUL showed no difference in urinary albumin/creatinine ratio, urine TGF-beta or mesangial matrix expansion.

Conclusions: Our data show that sulodexide can reduce the early, but not late, proteinuria in radiation nephropathy in rats. In addition, sulodexide did not affect urine TGF-beta established albuminuria or mesangial matrix expansion in a chronic model of diabetic kidney disease in mice. Although sulodexide may affect TGF-beta activation in radiation nephropathy, this effect appeared insufficient in this model to inhibit the expressions of PAI-1 and collagen and reduce accumulation of extracellular matrix. These results may explain in part its lack of efficacy in recent clinical trials of chronic kidney disease.

Figures

Fig. 1

Rats treated with sulodexide showed a trend for less glomerulosclerosis at 8 weeks compared to control animals (periodic acid-Schiff, ×200).

Fig. 2

PAI-1 protein expression by immunohistochemistry was reduced numerically in sulodexide-treated animals compared to controls at 8 weeks, although not significantly (anti-PAI-1 antibody immunohistochemistry, ×200).

Fig. 3

PAI-1/GAPDH mRNA ratio from whole kidney cortex was also reduced numerically in sulodexide-treated animals compared to controls at 8 weeks but not significantly.

Fig. 4

Glomerulosclerosis at 12 weeks was not different in control vs sulodexide-treated rats (periodic acid-Schiff, ×200).

Fig. 5

PAI-1 mRNA by (A) or northern blot (C) and protein expression by immunohistochemistry (B) at 12 weeks were not changed by sulodexide treatment (A, B, ×200).

Fig. 6

Phospho-Smad 2 expression was significantly decreased in sulodexide-treated compared control at 12 weeks.

Fig. 7

The expression of collagen I mRNA and the total collagen content were not different between the sulodexide-treated and control groups at 12 weeks.