Use of cyclophosphamide and other immunosuppressive drugs in the treatment of patients with lupus nephritis.

UNLABELLED: Systemic lupus erythematosus (SLE) is a chronic relapsing systemic autoimmune disease; one of the most serious complications is renal involvement, which is occurring in almost 50% of all patients at the beginning of the disease. The aim of the present study was to compare renal function, proteinuria, activity markers and treatment regimen of active and inactive SLE patients with renal involvement. We analyzed the correlation of serum blood urea nitrogen, creatinine level, glomerular filtration rate, urine total protein/serum creatinine (uTP/creat), CRP to classic activity markers of SLE (serum complement 3, -4 level, anti-dsDNA antibody). Moreover we analyzed the treatment modalities of patients with lupus nephritis (LN). Data of 418 SLE patients were analyzed, out of these patients 128 had biopsy proven lupus nephritis or had more than 3 + proteinuria by urine dipstick analysis (30% of all cases). RESULTS: Data of 128 patients with lupus nephritis were analyzed (mean age 32.18 +/- 11.48 year, time between the diagnosis of SLE and LN was 2.78 +/- 4.59 year). 48% of patients had diffuse proliferative glomerulonephritis, 75% of them received cyclic cyclophosphamide treatment. UTp (total protein)/creatinine level was significantly higher in active LN group (p = 0.03), and correlated to erythrocyte sedimentation rate (p = 0.002, R = 0.52). Mean anti-dsDNA level of patients with active LN was significantly higher (p < 0.001). CONCLUSIONS: Patients with active lupus nephritis are at higher risk of developing renal failure, activity markers and urine protein are elevated in these patients as compared to inactive patients, early aggressive immunosuppressive treatment needs to be started to prevent end-stage renal failure.

Dietary Na+ inhibits the open probability of the epithelial sodium channel in the kidney by enhancing apical P2Y2-receptor tone.

Apical release of ATP and UTP can activate P2Y(2) receptors in the aldosterone-sensitive distal nephron (ASDN) and inhibit the open probability (P(o)) of the epithelial sodium channel (ENaC). Little is known, however, about the regulation and physiological relevance of this system. Patch-clamp studies in freshly isolated ASDN provide evidence that increased dietary Na(+) intake in wild-type mice lowers ENaC P(o), consistent with a contribution to Na(+) homeostasis, and is associated with increased urinary concentrations of UTP and the ATP hydrolytic product, ADP. Genetic deletion of P2Y(2) receptors in mice (P2Y(2)(-/-); littermates to wild-type mice) or inhibition of apical P2Y-receptor activation in wild-type mice prevents dietary Na(+)-induced lowering of ENaC P(o). Although they lack suppression of ENaC P(o) by dietary NaCl, P2Y(2)(-/-) mice do not exhibit NaCl-sensitive blood pressure, perhaps as a consequence of compensatory down-regulation of aldosterone levels. Consistent with this hypothesis, clamping mineralocorticoid activity at high levels unmasks greater ENaC activity and NaCl sensitivity of blood pressure in P2Y(2)(-/-) mice. The studies indicate a key role of the apical ATP/UTP-P2Y(2)-receptor system in the inhibition of ENaC P(o) in the ASDN in response to an increase in Na(+) intake, thereby contributing to NaCl homeostasis and blood pressure regulation.