Stratégies pour faire régresser les lésions de fibrose rénale

Human bone morphogenetic protein-7 does not counteract aristolochic acid-induced renal toxicity

Aristolochic acids (AA) are nephrotoxic and profibrotic agents, leading to chronic kidney disease. As some controversial studies have reported a nephroprotective effect of exogenous recombinant human bone morphogenetic protein (rhBMP)-7 in several models of renal fibrosis, we investigated the putative effect of rhBMP-7 to prevent progressive tubulointerstitial damage after AA intoxication in vitro and in vivo. In vitro, the toxicity of AA on renal tubular cells was demonstrated by an increase in vimentin as well as a decrease in β-catenin expressions, reflecting a dedifferentiation process. Increased fibronectin and interleukin-6 levels were measured in the supernatants. Enhanced α-SMA mRNA levels associated to decreased E-cadherin mRNA levels were also measured. Incubation with rhBMP-7 only prevented the increase in vimentin and the decrease in β-catenin expressions. In vivo, in a rat model of AA nephropathy, severe tubulointerstitial lesions induced by AA after 10 and 35 days (collagen IV deposition and tubular atrophy), were not prevented by the rhBMP-7 treatment. Similarly, rhBMP-7 did not ameliorate the significant increase in urinary concentrations of transforming growth factor-β. In summary, our in vitro data demonstrated a poor beneficial effect of rhBMP-7 to reverse cell toxicity while, in vivo, there was no beneficial effect of rhBMP-7. Therefore, further investigations are needed to confirm the exact role of BMP-7 in progressive chronic kidney disease.

[Slowing chronic kidney disease progression: hopes and disappointments. Vascular repair of chronic kidney]

In chronic kidney disease patients, inexorable renal function decline is reduced by renin-angiotensin system (RAS) blockers. ACE inhibitors and angiotensin receptor blockers decrease blood pressure and proteinuria. Guidelines recommend a reduction of blood pressure to less than 130/80 mmHg and urinary protein excretion below 0.5 g/d. The combined use of a diuretic increases anti-proteinuric effect and blood pressure control of RAS blockers. Drugs as mineralo-corticocoids receptor antagonist and endothelin receptor antagonists reduce further albuminuria in combination with RAS blocker, but side effects need to be precised. Both metabolic acidosis and hyperuricemia represent new therapeutic goals to slow renal function decline in CKD patients. Renal fibrosis treatment and regenerative medicine are stemming and will be important issues for kidney and other organs in the future.

[Pathological peculiarities of chronic kidney disease in patient from sub-Saharan Africa. Review of data from the Democratic Republic of the Congo]

Chronic kidney disease (CKD) is a major global public health problem. But kidney involvement is more common and appears more severe in Africa than in developed countries. The likely causes of end stage renal disease (ESRD) or CKD stage 3 and above in developed countries are diabetes, hypertension and less frequently glomerular diseases. In contrast, in decreasing order in Africa are glomerulopathies, hypertension and diabetes. The reasons for this preponderance of glomerular diseases are not fully known but may be linked to the persistence or reemergence of tropical diseases. This study reviews the kidney involvements more associated with common tropical diseases including HIV/AIDS. The most common HIV/AIDS lesion is a specific focal and segmental glomerulosclerosis (FSGS) termed HIV-associated nephropathy (HIV-AN). Renal complications of tropical parasites are heterogenous. Various glomerulopathies like FSGS occur during various filariasis infections. Schistosoma mansoni is responsible for membranoproliferative glomerulonephritis and amyloidosis. Human African trypanosomiasis is associated with cryoglobulinemic membranoproliferative glomerulonephritis. The Plasmodium malariae is mainly responsible for membranoproliferative glomerulonephritis. Acute patterns (acute tubular necrosis or acute postinfectious glomerulonephritis) are observed during Plasmodium falciparum infection. Several other viral, bacterial or mycobacterial infections like leprosy and tuberculosis still prevalent in Africa can also affect the kidney. Sickle cell disease is responsible for a variety of renal injuries. In conclusion, kidney lesions linked to tropical diseases partly explain the peculiar pattern of CKD of the black race and play a significant role in the current outbreak of the CKD in Subsaharan Africa.