We conclude that renin inhibition modulates anti-angiogenesis signaling independently of blood pressure by increasing angiopoietin-1/angiopoietin-2 ratio. This promotes in SHR stabilization of endothelial cells, favors pro-angiogenic action and consequently results in higher capillary density.

Chronic allograft injury (CAI) is a major cause of late graft failure with a multifactorial pathogenesis; however, in different experiments an inhibition of the renin-angiotensin system by angiotensin-converting enzyme inhibitors and angiotensin II type 1 receptor blockers ameliorated the progression of chronic renal disease. Different concepts supposed that aldosterone is involved in development and/or progression of renal diseases via interaction with a non-epithelial mineralocorticoid receptor (MR), e.g. reducing neointima formation. Our examinations therefore targeted on the effects of the aldosterone synthase inhibitor fadrozole and the MR antagonist spironolactone compared to vehicle in an established rat model of CAI. In our model of CAI, neither the aldosterone biosynthesis inhibitor nor a direct MR blockade had a positive effect on renal CAI in rats. Fadrozole- and spironolactone-treated animals demonstrated a higher proteinuria value, pathologically elevated potassium values, higher tubulointerstitial damage and markedly increased heart weight/body weight as compared to vehicle. Our observations also suggest that inhibition of the MR or the biosynthesis itself had a bad influence on the amount of sclerotic glomeruli and tubulointerstitial damage. The positive effects of inhibition of aldosterone as described in cardiac models could not yet be detected in kidney recipients.

Conclusion: sCyC is an endogenous marker of GFR. Its limitations relate to its being affected by high doses of steroids in the fi rst days following transplantation. After a week post transplantation, it is correlated with CrC in a 24-hour urine. So after a week post renal transplantation sCyC is a reliable marker of kidney function.