Development Of Renal Impairment Research Articles

Evidence of gene-gene interactions in the genetic susceptibility to renal impairment after unilateral nephrectomy.

The number of patients with hypertension-associated end-stage renal failure (ESRF) continues to increase despite improved antihypertensive management and early detection programs. Variation for the development of renal complications in hypertension may reflect independent genetic susceptibility to ESRF. The genetically hypertensive fawn-hooded rat is characterized by the early presence of systolic hypertension, glomerular hypertension, progressive proteinuria (UPV), and focal glomerulosclerosis (FGS), resulting in premature death as a result of renal failure. In the present study, the genetic basis of hypertension-associated ESRF in an F2 intercross consisting of 337 animals, in which systolic BP, UPV, albuminuria, and FGS, were studied at 8 wk after a unilateral nephrectomy performed at 5 to 6 wk of age. A total genome scan, consisting of 418 markers, was used to identify regions that contribute to the pathogenesis of UPV and FGS. Linkage analysis revealed five loci involved in the development of renal impairment. Of these five, two (Rf-1, Rf-2) had been identified previously. There seems to be strong interactive effects between the various loci and their impact on UPV and the other parameters of renal impairment, as well as an interaction with BP. In particular, Rf-1 seems to play a major role in determining the severity of the disease. This study is the first to report the interaction of more than two loci to produce progressive renal failure, suggesting that the genetic dissection of renal failure in humans will require understanding of how multiple genes interact with each other and BP to produce ESRF.

Acute cholestasis-induced renal failure: Effects of antioxidants and ligands for the thromboxane A2 receptor

Acute biliary obstruction is associated with the development of renal impairment and oxidative stress. The F2-isoprostanes, formed during oxidant injury, are renal vasoconstrictors acting via thromboxane (TX)-like receptors. We determined whether the formation of F2-isoprostanes is increased in experimental cholestasis and whether thiol containing antioxidants or ligands for the TXA2 receptor could improve renal function. The effects on renal function of acute bile duct ligation (BDL) in the rat were studied for two days. The consequences of administration of N-acetylcysteine (NAC), alpha-lipoic acid (LA), the TX receptor antagonist (TXRA) BAYu3405, or placebo were then examined. BDL caused a reduction in creatinine clearance from 1.10 +/- 0.05 to 0.55 +/- 0.05 ml/min and sodium excretion from 52 +/- 3 to 17 +/- 3 micromol/hr. Urinary F2-isoprostanes increased from 14 +/- 2 to 197 +/- 22 pg/ml following BDL. Renal functional changes were ameliorated by NAC (creatinine clearance 0.73 +/- 0.05 ml/min), LA (0.64 +/- 0.03 ml/min), and a TXRA (0.90 +/- 0.15 ml/min); P < 0.05. Similarly, sodium excretion was increased from 17 +/- 3 micromol/hr (placebo) to 34 +/- 3 micromol/hr (NAC), 29 +/- 3 micromol/hr (LA), and 38 +/- 5 micromol/hr (TXRA); P < 0.005. Hepatic glutathione concentrations increased from 6.5 +/- 0.3 micromol/g (normal liver) to 8.8 +/- 0.5 micromol/g (NAC) and 7.7 +/- 0.3 micromol/g (LA), P < 0.01. However, only LA markedly inhibited F2-isoprostane formation (197 +/- 22 to 36 +/- 11 pg/ml creatinine clearance; P < 0.05). Urinary TXB2 excretion was elevated after BDL (2.2 +/- 0.5 to 111.1 +/- 20.3 pg/min) but was unaffected by NAC and LA. NAC, LA, and TXRA can partially prevent renal dysfunction in experimental cholestasis. The effects of the antioxidants are independent of their ability to inhibit lipid peroxidation or TX synthesis.

Urine output in the first twelve hours after cardiopulmonary bypass does not predict the development of renal impairment

Urine output in the first twelve hours after cardiopulmonary bypass does not predict the development of renal impairment

Tumor necrosis factor and interleukin-6 in spontaneous bacterial peritonitis in cirrhosis: relationship with the development of renal impairment and mortality.

Spontaneous bacterial peritonitis (SBP) is associated with an important production of inflammatory mediators. However, it is unknown whether there is a relationship between the abdominal production of these mediators and the development of renal impairment, one of the most important prognostic parameters in spontaneous bacterial peritonitis. We studied 52 cirrhotic patients at diagnosis and resolution of the infection, by measuring endotoxin, tumor necrosis factor (TNF), and interleukin-6 (IL-6) levels in plasma and ascitic fluid. Thirteen patients (25%) developed renal impairment. Patients developing renal impairment showed significantly higher plasma and ascitic fluid cytokine levels at diagnosis of infection than patients who did not (plasma TNF-alpha: 96.0+/-38.7 vs. 39.1+/-3.6 pg/mL, P=.0209; ascitic fluid TNF-alpha: 474.5+/-118.1 vs. 160.8+/-42.7 pg/mL, P=.0173; plasma IL-6: 6,635+/-2,897 vs. 458+/-109 pg/mL, P=.0004; ascitic fluid IL-6: 182,559+/-47,328 vs. 39,250+/-10,803 pg/mL, P=.0001). Independent predictors of development of renal impairment at diagnosis were: renal failure (blood urea nitrogen > 30 mg/dL or serum creatinine > 1.5 mg/dL) (P < .001), IL-6 levels in ascitic fluid (P < .001), and mean arterial pressure (P < .05). Ten of the 13 (77%) patients who developed renal impairment died during hospitalization, but only 2 of the 39 (5%) patients who did not (P=.0001). In addition, renal failure at diagnosis of the infection was the only independent predictor of hospital mortality (P < .001). In conclusion, the inflammatory response to the infection may be an important mechanism of renal impairment and the associated mortality in SBP.

Sodium-Lithium Countertransport Kinetics in IgA Nephropathy: Relation to Plasma Lipids and Renal Impairment

We have investigated the activity and kinetics of sodium-lithium countertransport (SLC) in patients with IgA nephropathy and their relationship to plasma lipids. Standard SLC activity, the Michaelis constant (Km) and maximum velocity (Vmax) were measured in patients who had IgA nephropathy with either normal serum creatinine (IgA-NRF), or raised serum creatinine (IgA-IRF), and normal subjects (NC). The standard SLC activity was raised in hypertensive patients with IgA-NRF due to a raised Vmax in association with hyperlipidaemia. The Km was significantly lower and Vmax also tended to be lower in IgA-IRF. Km and Vmax were not different in IgA-NRF compared with the NC. There was no difference in the mean standard SLC activity between all three groups. The low Km and low Vmax resulted in a normal standard SLC activity being observed in IgA-IRF which is similar to the situation we have observed in a proportion of diabetic patients with nephropathy. The low Km in patients with IgA nephropathy may be due to inheritance associated with familial essential hypertension or to an acquired change of the kinetics related to a change in the environment of the plasma membrane during the development of renal impairment.

THE ROLE OF ENDOTHELIN IN THE PATHOPHYSIOLOGY OF RENAL IMPAIRMENT DURING ACUTE LIVER REJECTION1

We assessed the role of endothelin in the development of renal dysfunction during acute rejection by examining the effect of a selective endothelin A (ETA) receptor antagonist BQ-123 in rats with acute liver rejection. Serum endothelin levels and endogenous creatinine clearance (Ccr) were monitored on days 1, 3, 5, 7, and 9 postoperatively. As indicators of renal hemodynamics, the estimated hemoglobin concentration of renal tissue (IHb) and the oxygen saturation of hemoglobin in renal blood (ISO2) were determined by reflectance spectrophotometry. In addition, the clearance of inulin and P-aminohippurate were determined, and the renal tissue blood flow was estimated by laser-Doppler flowmetry (LDF). As a model of allograft rejection, Lewis rats were transplanted orthotopically with DA rat livers. The serum endothelin level of allografted rejectors was significantly (P < 0.05) higher than that of isografted controls (Lewis rats with Lewis livers) on postoperative day 5, and it increased to a maximum of 5.38 +/- 0.95 pg/ml on day 9 (versus 1.23 +/- 0.18 pg/ml preoperatively). The values of Ccr, IHb, and ISO2 were all significantly (P < 0.05) lower in allografted rejectors than in isografted controls on day 5, and subsequently declined to a minimum on day 9 (P < 0.01). Treatment of allografted rejectors with BQ-123 markedly improved the renal parameters to levels similar to those in the isografted controls. These results strongly suggest that endogenous endothelin may play an important role in the development of renal impairment during acute liver rejection by reducing renal blood flow through binding with ETA receptor.

Paracentesis in the management of cirrhotic ascites

During the last few years, several studies including six randomised, controlled trials reevaluating therapeutic paracentesis in the management of cirrhotic patients with tense ascites have been reported. The main findings of these investigations are: (i) Repeated large-volume paracentesis (evacuation of 4-6 l/day until complete mobilization of ascites) or total paracentesis (complete mobilization of ascites in only one tap) associated with i.v. albumin infusion (6-8 g/l of ascitic fluid removed) are more effective in eliminating the intra-abdominal fluid than conventional diuretic therapy, are associated with a lower incidence of complications and considerably reduce the duration of hospital stay and the cost of treatment; (ii) The mobilization of ascites by paracentesis without albumin infusion is associated with an impairment in effective circulating blood volume, as indicated by a decrease in cardiac output, central venous pressure, pulmonary capillary wedge pressure and plasma concentration of atrial natriuretic peptide and a marked elevation of plasma renin activity and aldosterone concentration. In 20% of patients this circulatory disturbance is accompanied by the development of renal impairment and/or dilutional hyponatraemia. These changes can be detected within the first 24 h following complete mobilization of ascites and do not occur when plasma volume is expanded with albumin; (iii) Hemaccel and dextran 70 appear to be as effective as albumin in preventing renal and electrolyte complications after paracentesis; (iv) Therapeutic paracentesis is an alternative treatment to peritoneovenous shunting in cirrhotic patients with refractory ascites.

Renal impairment in myeloma: negative association with isoelectric point of excreted Bence-Jones protein.

The isoelectric point (pI) of the major form of Bence-Jones protein excreted by 62 patients with myeloma and six with macroglobulinaemia was measured by combining isoelectric focusing with immunoblotting techniques. The distribution of the pI values for both kappa and lambda type proteins was bimodal, most falling in the ranges 5.0-6.0 and 7.0-7.5. Plasma creatinine and creatinine clearance and the urine excretion of alpha-1-microglobulin and beta-2-microglobulin were measured in 24 of the patients. These patients, who were free of additional factors known to have an association with the development of renal impairment, were followed up for a mean period of 16 months (range three to 28 months). It was found that renal impairment was not related to the pI of the Bence-Jones protein excreted.

Chronic renal insufficiency (CRI) in urolithiasis.

In 80 adult kidney stone formers (52 with reversible and 28 with irreversible renal impairment) laboratory and clinical data were evaluated to estimate the share of abnormalities in the metabolism of stone forming substances in the development of renal impairment, and to search for the causes of the irreversibility of renal impairment. The study confirmed the previous results from this laboratory suggesting a causal relationship between renal impairment and metabolic disorders. No significant differences in the incidence of metabolic disorders or in therapy have been found in patients with irreversible renal impairment as compared to those with progressive deterioration of renal function. Irreversible renal impairment developed in relationship with bilateral kidney stone formation and recurrent urinary infection.

Development of renal impairment in Laennec's cirrhosis.

Development of renal impairment in Laennec's cirrhosis.