Inhibition and reversibility of renal changes: lessons from diabetic kidney disease

Effect of Acacia senegal on TGF-β1 and vascular mediators in a rat model of diabetic nephropathy

CONTEXT

Transforming growth factor-β1 (TGF-β1), endothelin-1 and angiotensin II are responsible for extracellular matrix accumulation within the kidney in diabetic nephropathy.

OBJECTIVE

This study evaluated the effect of adding Gum Arabic (GA) and insulin on serum glucose, renal function, TGF-β1, endothelin-1, and angiotensin II in rats with diabetic nephropathy.

METHODS

Sixty male Sprague-Dawley rats were divided into; normal, normal plus GA, diabetic rats (DM), DM plus insulin, DM plus GA, and DM plus insulin plus GA groups. Levels of glucose and creatinine in serum, TGF-β1, angiotensin II, and endothelin-1 in renal homogenate and HbA1c were measured.

RESULTS

Serum creatinine, TGF-β1, angiotensin II, and endothelin-1 were increased in diabetic rats. GA decreased serum glucose, TGF-β1, angiotensin II, endothelin-1, and HbA1c in diabetic rats. GA and insulin decreased serum glucose, creatinine, TGF-β1, angiotensin II, endothelin-1, and HbA1c in diabetic rats.

CONCLUSION

Co-administration of GA with insulin to rats with diabetic nephropathy improved the glycemic state, renal function, TGF-β1, endothelin-1, and angiotensin II.

Herba Artemisiae Capillaris Extract Prevents the Development of Streptozotocin-Induced Diabetic Nephropathy of Rat

Diabetic nephropathy (DN) is a major cause of end-stage renal disease throughout the world; until now there is no specific drug available. In this work, we use herba artemisiae capillaris extract (HACE) to alleviate renal fibrosis characterized by the excessive accumulation of extracellular matrix (ECM) in rats, aiming to investigate the protective effect of the HACE on DN. We found that the intragastric treatment of high-dose HACE could reverse the effect of streptozotocin not only to decrease the level of blood glucose and blood lipid in different degree but also further to improve renal functions. It is worth mentioning that the effect of HACE treatment was comparable to the positive drug benazepril. Moreover, we found that HACE treatment could on one hand inhibit oxidative stress in DN rats through regulating enzymatic activity for scavenging reactive oxygen species and on the other hand increase the ECM degradation through regulating the activity of metalloproteinase-2 (MMP-2) and the expression of tissue transglutaminase (tTG), which explained why HACE treatment inhibited ECM accumulation. On the basis of above experimental results, we conclude that HACE prevents DN development in a streptozotocin-induced DN rat model, and HACE is a promising candidate to cure DN in clinic.

Possible role of transforming growth factor-β1 and vascular endothelial growth factor in Fabry disease nephropathy

Fabry disease is a lysosomal storage disorder (LSD) caused by deficiency of α-galactosidase A (α-gal A), resulting in deposition of globotriaosylceramide (Gb3; also known as ceramide trihexoside) in the vascular endothelium of many organs. A gradual accumulation of Gb3 leads to cardiovascular, cerebrovascular and renal dysfunction. Endothelial cell dysfunction leads to renal complications, one of the main symptoms of Fabry disease. However, the pathological mechanisms by which endothelial dysfunction occurs in Fabry disease are poorly characterized. The purpose of this study was to investigate whether the expression of transforming growth factor-β1 (TGF-β1) and vascular endothelial growth factor (VEGF) is associated with the renal pathogenesis of Fabry disease. We found that the protein expression levels of renal thrombospondin-1 (TSP-1), TGF-β1 and VEGF were higher in the kidneys from Fabry mice compared to wild-type mice. The expression levels of VEGF receptor 2 (VEGFR2), fibroblast growth factor-2 (FGF-2) and phospho-p38 (P-p38) were also higher in the kidneys from Fabry mice compared with wild-type mice. Activities of cysteine aspartic acid protease (caspase)-6 and caspase-9 were higher in kidneys from Fabry than from the wild-type mice. These results suggest that overexpression of TGF-β1 and VEGF in the Fabry mouse kidney might contribute to Fabry disease nephropathy by inducing apoptosis. To test whether Gb3 accumulation can induce apoptosis, we incubated bovine aortic endothelial cells with Gb3 and found increased expression of TGF-β1, VEGFR2, VEGF, FGF-2 and P-p38. The combination of increased expression of TGF-β1 and VEGF caused by Gb3 accumulation may allow upregulation of FGF-2, VEGFR2 and P-p38 expression, and these changes may be associated with Fabry disease nephropathy by inducing apoptosis.