ABSTRACT
In this study, we evaluated the actions of Crotalus durissus cumanensis venom (CDCmV), and its crotoxin (Crtx) fraction, on renal and vascular functions in Wistar rats. In isolated perfused kidneys, CDCmV (10 µg/mL) significantly increased the perfusion pressure (PP) from 110.7 ± 2.4 to 125.3 ± 2.8 mmHg after 30 minutes. This effect was accompanied by an increased renal vascular resistance (RVR) from 5.4 ± 0.1 to 6.2 ± 0.2 mmHg/mL.g-1.min-1. We observed decreases in urinary flow (UF) from 0.13 ± 0.01 to 0.05 ± 001 mL.g-1.min-1 and glomerular filtration rate (GFR) from 0.66 ± 0.06 to 0.18 ± 0.02 mL.g-1.min-1. Crtx did not change PP or RVR, but diminished GFR (from 0.65 ± 0.05 to 0.26 ± 003 mL.g-1.min-1) and UF (from 0.11 ± 0.008 to 0.09 ± 0.008 mL.g-1.min-1). Both CDCmV and Crtx reduced the percentage of tubular transport of sodium, chloride and potassium. The cytotoxicity of these substances against MDCK cells was tested by the MTT method: only CDCmV caused a decrease in the cell viability with an IC50 of 5.4 µg/mL. In endothelium-intact isolated aortic rings, CDCmV (0.1 to 30 µg/mL) increased the sustained phenylephrine-induced contraction to a value of 130.0 ± 6.6 percent of its corresponding control, but showed a relaxant effect in endothelium-denuded preparations. Similar results were observed in aortic rings contracted with potassium (40 mM). Crtx was ineffective in aortic ring assays. Thus, it is reasonable to suggest that the renal effects induced by the CDCmV may be due to its influence on the endothelium's ability to release factors that can alter the contractile behavior of vascular smooth muscle. In conclusion, CDCmV is toxic to kidney cells. It changes parameters of the renal function including the glomerular filtration rate, renal vascular resistance and tubular transport. The actions induced by CDCmV also involve endothelium-dependent vasoactive properties. Their effects may be only partially attributed to Crtx.
Subject(s)
Animals , Female , Rats , Crotalus , Crotoxin , Rats, Wistar , Crotalid Venoms/toxicityABSTRACT
Se analiza un grupo de 25 pacientes sometidos a trasplante renal, con una edad media de 11=3 años, 9 niñas y 16 varones. Se utilizaron 22 injertos de dador vivo y 3 de cadaver. El peso corporal era menor de 25 kg. En el 60 por ciento de la poblacion y todos tenian deficit pondoestatural. Las uropatias (12/25) y las glomerulopatias (9/25), fueron las enfermedades de base mas frecuentes que llevaron a estos pacientes a la insuficiencia renal. La tasa de mortalidad fue del 12 por ciento (3 casos). Las complicaciones postoperatorias y la tasa de mortalidad fueron mayores para los injertos cadavericos, pero sin significancia estadistica por el numero de casos. Los reimplantes ureterales se realizaron con tecnica de Politano-Leadbetter en 22 y con tecnica de Gregoire en 3. Las complicaciones precoces mas frecuentes fueron la discracia sanguinea (4/25) y el rechazo agudo (5/25). Las tardias fueron la infeccion urinaria (4/25) y el rechazo cronico (3/25). Catorce injertos presentan un clearence > de 80 ml/min y 2 entre 40-45 ml/min. La sobrevida actuarial del injerto fue de 64 por ciento, siendo el rechazo la principal causa de fracaso. Cuatro pacientes tenian reconstrucciones del tracto urinario a traves de un reservorio continente y mecanismo de cateterismo limpio por la tecnica de Mitrofanoff. Se concluye que el trasplante renal es una opcion terapeutica para niños con enfermedades renales, que tiene baja mortalidad y complicaciones locales del facil manejo