Favorable outcome of IgA nephropathy on antituberculous treatment.

We report the case of an association of IgA nephropathy and tuberculosis with superimposed vasculitis lesions on the renal biopsy. Three previous cases of the same association are discussed. The nephropathy had a favorable course in all of these cases on antituberculous treatment only. Tuberculosis is another infection related to IgA nephropathy.

PPAR-gamma-agonists' renal effects.

PPAR-gamma ligands, including thiazolidinediones, have recently become clinically available for treating insulin-resistant diabetes mellitus. Accumulating evidence suggests that these drugs not only significantly improve insulin sensitivity but also may have antiproteinuric effects in genetically obese diabetic rodents and patients with type II diabetes and diabetic nephropathy. Moreover, troglitazone reduced expression of ECM proteins and transforming growth factor-beta in glomeruli from streptozotocin-induced diabetic rats. Many other properties including antiproteinuric, hemodynamic, and antihypertensive effects in insulin-dependent diabetes mellitus suggest that PPAR-gamma ligands might have a direct, beneficial renal effect, independent of their capacity to improve glucose tolerance. Besides their antidiabetic effects, thiazolidinediones have been shown to lower blood pressure in diabetic patients with hypertension and patients with diabetic nephropathy through multiple mechanisms. Several studies showed the efficacy of PPAR-gamma agonists to ameliorate the progression of glomerulosclerosis. The effect is independent of insulin effects and could only be partially due to lipid effects. These renal protective effects of PPAR-gamma agonists suggest that they may provide a novel intervention strategy to prevent vascular and glomerular sclerosis.

Renal effects of PPARalpha-agonists.

Peroxisome proliferator-activated receptor alpha (PPARalpha) is a member of the large nuclear receptor superfamily. Its main role is to activate genes involved in fatty acid oxidation in the liver, heart, kidney and skeletal muscle. While they are mainly used as hypolipidemic agents, PPARalpha agonists may also be postulated to exhibit renoprotective effects. This review summarizes current knowledge regarding the effects of PPARalpha agonists on the kidney.

An appraisal of antiretroviral drugs in hemodialysis.

BACKGROUND: Acquired immunodeficiency syndrome (AIDS)-related kidney disorders concern 30% of those patients and can lead to end-stage renal disease (ESRD; 6 to 10%). Therefore, the administration of antiretroviral drugs in human immunodeficiency virus (HIV) patients with nephropathy is not uncommon. METHODS: The influence of ESRD on the different phases of the pharmacokinetic profile of drugs in general is examined in light of bioavailability, distribution, protein binding, metabolism, and elimination. Then, the pharmacokinetics of antiretroviral drugs in hemodialysis are detailed. RESULTS: From these data, dosing recommendations are given for nucleoside reverse transcriptase inhibitors (NRTIs), non-NRTIs, and protease inhibitors (PIs). CONCLUSION: Dosage adjustments are often necessary for patients with renal insufficiency. These adaptations have to be carefully performed to optimize drug exposure and reduce the risk of side effects.

Dose effect relationship of reviparin in chronic hemodialysis: a crossover study versus nadroparin.

Low molecular weight heparins (LMWHs) are used for prevention of clotting in the dialysis circuit. The aim of this trial was to define the optimal dose of a new LMWH and to test the efficiency of a single dose at the start of the session. Fifteen patients were treated according to a double blind and crossover design during 4 blocks of 5 consecutive reviparin doses assigned randomly as 50, 60, 70, 85, and 100 IU anti-Xa/kg. Assessment was carried out on screening of fibrin rings or clots in the arterial and venous air traps and on visual detection of fiber in the dialyzer after rinsing. These clinical results were compared to plasmatic anti-Xa activity and thrombin-antithrombin (TAT) complex generation. A standard dose of 70 IU anti-Xa/kg of nadroparin was used as the control. After a bolus of 50 to 100 IU anti-Xa/kg, the occurrence of fibrin rings and clots in the air traps was dependent on three factors: dose of LMWH, time of the session, and patient status. A bolus of 85 IU anti-Xa/kg of reviparin was effective and safe for sessions of 4 h. For this dose, plasmatic anti-Xa activity was 0.96 +/- 0.28 IU/ml at Hour 2 and 0.82 +/- 0.22 IU/ml at Hour 4. TAT complexes are good markers of the activation of the coagulation. They did not increase during a 4 h session after a reviparin bolus of 100 IU/kg. For the same LMWH dose, the trial shows a great variability of the clinical effect and anti-Xa activities from one patient to another. A single dose of 85 IU anti-Xa/kg of reviparin can be used at the start of the dialysis session as a loading dose. We advise adapting the dose during the subsequent sessions according to the appearance of the blood circuit. The benefit of monitoring anti-Xa activity and TAT complexes could be tested in a further trial.

Use of gadolinium-based contrast agent for renal angiography: case report and review of the literature.

A 67-year-old woman suffering from chronic renal failure (Creatinine 480 micromol/L) underwent a gadolinium renal angiography, which visualized a stenosis of the right renal artery. There was no deterioration of renal function after the arteriography. A review of the literature is presented which show the efficiency of this technique to visualize the renal arteries, and the absence of nephrotoxicity after the use of gadolinium as a based contrast agent in high risk patients.

Abnormal fibrin clot architecture in nephrotic patients is related to hypofibrinolysis: influence of plasma biochemical modifications: a possible mechanism for the high thrombotic tendency?

Porosity, viscoelasticity and morphological properties of plasma fibrin from 16 nephrotic patients and 16 healthy volunteers were compared. Nephrotic patients were characterized by formation of tight and rigid plasma fibrin gels which resulted in a slower rate of fibrin lysis studied either under pressure-driven permeation or diffusional transport of fibrinolytic agents. These latter findings indicated that both abnormal fibrin network conformation and abnormal fibrin fiber structure were involved in hypofibrinolysis. Albumin supplementation up to 40 mg/ml partially restored normal fibrin architecture and increased the rate of fibrinolysis in these patients. Multiparametric analysis showed that nephrotic patients were mainly characterized by a low plasma albumin level (R = -0.85), a low albumin to fibrinogen ratio (R = -0.89) and a high resistance to lysis (R = -0.82). High triglycerides level was the only plasma modification related to the slower fibrin lysis rate (R = -0.54). High fibrin rigidity (G') was the only fibrin parameter simultaneously related to the nephrotic state (R = 0.75) and the lysis resistance (R = -0.71). After eliminating the effects of age, albumin and fibrinogen levels, low fibrin porosity (Ks) and low fiber mass-length ratio (mu) were the main features of the nephrotic state. These findings are discussed in relation to both the pathophysiology of thrombotic complications in nephrotic syndrome and their pharmacological prevention.

Renal involvement in systemic lupus erythematosus. A study of 180 patients from a single center.

Charts of 180 patients (147 women, 33 men) with systemic lupus erythematosus (SLE) complicated by renal involvement were retrospectively analyzed from a series of 436 patients. Mean age at renal disease onset was 27 years. Thirty-six percent of the patients had renal involvement after diagnosis of lupus, for 30.7% of that group it was more than 5 years later. Renal involvement occurred more frequently in young male patients of non-French non-white origin. Patients with renal involvement suffered more commonly from malar rash, psychosis, myocarditis, pericarditis, lymphadenopathy, and hypertension. Anemia, low serum complement, and raised anti-dsDNA antibodies were more frequent. According to the 1982 World Health Organization classification, histologic examination of initial renal biopsy specimen in 158 patients showed normal kidney in 1.5% of cases, mesangial in 22%, focal proliferative in 22%, diffuse proliferative in 27%, membranous in 20%, chronic sclerosing glomerulonephritis in 1%, and other forms of nephritis in 6.5%. Distribution of initial glomerulonephritis patterns was similar whether renal involvement occurred before or after the diagnosis of lupus. Transformation from 1 histologic pattern to another was observed in more than half of the analyzable patients (those who underwent at least 2 renal biopsies). Nephritis evolved toward end-stage renal disease in 14 patients despite the combined use of steroids and cyclophosphamide in 12. Initial elevated serum creatinine levels, initial hypertension, non-French non-white origin, and proliferative lesions on the initial renal biopsy were indicators of poor renal outcome. Twenty-four patients died after a mean follow-up of 109 months from SLE diagnosis. Among our 436 patients, the 10-year survival rate was not significantly affected by the presence or absence of renal involvement at diagnosis (89% and 92%, respectively).

Clopidogrel activities in patients with renal function impairment.

OBJECTIVES: To assess the tolerability, pharmacodynamic effects and pharmacokinetic parameters after repeated doses of clopidogrel (Plavix((R))) in patients with moderate or severe renal failure. PATIENTS: Eight patients with severe renal failure (endogenous creatinine clearance 5 to 15 ml/min) and eight patients with moderate renal impairment (endogenous creatinine clearance 30 to 60 ml/min) were included. STUDY DESIGN: An open, uncontrolled, parallel-group study over 8 days' administration of 75mg once-daily clopidogrel. METHODS: Measurement of changes in ADP-induced platelet aggregation and skin bleeding time and of plasma concentrations and urinary excretion of clopidogrel and its main metabolite, SR 26334. Assessment of clinical tolerance and serial haematological and biochemical investigations. RESULTS: At the end of the dosage period, platelet aggregation was equally inhibited, by about 25%, and bleeding time equally extended, by a factor of about 2, in the two groups. There were no tolerability concerns. Maximum plasma concentration (C(max)) and time to reach C(max ) (t(max)) for clopidogrel were not significantly different between the two groups. SR 26334 excreted into the urine and renal clearance rate were significantly lower in the severely impaired group, while plasma elimination half-lives were not significantly different. C(max) and t(max) did not differ significantly between the two groups, but trough levels and area under the plasma concentration-time curve from zero to 24 hours (AUC(0-24h)) after the last dose were significantly higher in the moderately impaired group. CONCLUSIONS: Clopidogrel 75mg once daily was well tolerated in patients with either moderate or severe renal failure, and provided good inhibition of ADP-induced platelet aggregation without excessive extension of bleeding time. Dose adjustment in such patients does not appear to be required.

Monthly intravenous pulse cyclophosphamide therapy in Wegener's granulomatosis.

OBJECTIVE: To study the long term effects of monthly intravenous cyclophosphamide therapy in Wegener's granulomatosis. METHODS: Fourteen consecutive patients with active Wegener's granulomatos treated with a first-line combination of high-dose prednisone and monthly intravenous pulse cyclophosphamide were retrospectively studied. RESULTS: One patient died from septicemia complicating severe leukopenia after the first pulse. At 8 months after instituting intravenous pulse cyclophosphamide therapy, failure was observed in 6 other patients. Between month 16 and 18, 2 other patients relapsed when the time between 2 pulses was lengthened. Five patients developed cyclophosphamide-related side-effects: infection (n = 2), amenorrhea (n = 1), alopecia (n = 2) and vomiting (n = 2). Except for one fatal infection, no major side-effect of intravenous cyclophosphamide therapy was observed. At the end of the study, all patients were off intravenous cyclophosphamide therapy with more than 6 months of followup. The 6 responders were in remission on low-dose prednisone or without treatment. CONCLUSION: A combination of high-dose prednisone and intravenous cyclophosphamide may achieve long-term remission in 42% of patients with Wegener's granulomatosis. Responders to intravenous cyclophosphamide therapy had less extensive disease than non-responders.

Electrophoretic study of the physico-chemical characteristics of Bence-Jones proteinuria and its association with kidney damage.

AIM: To identify a physico-chemical criterion, or set of criteria, explaining and possibly predicting the nephrotoxic behaviour of Bence-Jones proteins (BJP). METHODS: The electrophoretic mobility and isoelectric point (pI) of 92 BJP isolates were determined using various electrophoresis procedures on polyacrylamide gel. The proportions of monomers and dimers were determined using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS PAGE) in 58 cases. PAGE data for 10 BJP isolates were used to construct Ferguson plots and titration curves. RESULTS: The distribution of electrophoretic mobility and pI values was bimodal and showed a positive correlation when the pI was above 6. The values of these two parameters in 22 patients with renal impairment were not significantly different from those in the patients without renal impairment, and the statistical analysis showed no predictive value for the onset of renal impairment. However, patients excreting the lambda light chain isotype had a 2.8-fold higher risk of developing renal impairment compared with the other patients. Studies of the charge variation of the protein with pH indicated three types of behaviour, suggesting that the charge of BJP is highly variable at physiological pH. CONCLUSION: It is important to study not only the positivity or negativity of the BJP charge at a given pH, but also its intensity. The study of the BJP titration curves in patients with renal impairment suggests that a low charge at physiological urinary pH could predict renal impairment.

Is overhydration in CAPD patients a contraindication to renal transplantation?

Over a 14 year period, 56 of 415 CAPD patients (34 male, 22 female), aged 42.7 +/- 11 years, underwent renal transplantation (TR). A cadaver kidney was used in 53 patients (kidney-pancreas in 2), and a human leucocyte antibody (HLA) identical related donor organ was used in 3. Underlying renal diseases were chronic glomerulonephritis in 30 patients, diabetic nephropathy in 10, interstitial nephropathy in 5, vascular in 4, polycystic kidney in 3, and undetermined in 4. Mean duration of CAPD prior to TR was 13 months (2-56 months). A three-week peritonitis episode-free interval was requested prior to TR. At year 1, actuarial patient and graft survival (96% and 86%, respectively), plasma creatinine, and number of rejection episodes were not different from those recorded in patients treated with hemodialysis (HD) prior to TR. At TR, pulmonary artery pressure (PAP) was elevated (average 21.1 +/- 7.4 mm Hg), > or = 25 mm Hg and > or = 30 mm Hg in 36% and 14.6% of CAPD patients, respectively. Post-TR, HD was performed in 4 patients; no peritoneal infection occurred. Postoperative sonography disclosed ascitis in 12.7% of CAPD patients. The PD catheter was removed two months post-TR. Hemodynamic findings at TR suggest a frequently underestimated overhydration in CAPD patients, which should be detected and treated in order to reduce acute cardiovascular complications at TR.

Pharmacokinetics of a low molecular weight heparin (reviparine) in hemodialyzed patients.

Low-molecular-weight heparins (LMWHs) are used to prevent clotting in hemodialysis extracorporeal blood circuits. In order to test the possibility of using reviparine (a LMWH of 3,900 D) in this indication, we studied the pharmacokinetics of the drug after a mean dose of 3,300 IU anti-Xa in 10 hemodialyzed patients. Reviparine was administered subcutaneously between two dialysis sessions and intravenously at the start of 20 dialysis sessions performed either with high (HP) or low-permeability (LP) membranes. We observed a moderate increase of the elimination half-life of reviparine (T1/2: 5 +/- 1.6 h between dialysis, 3.6 +/- 1.3 during dialysis with an HP membrane and 4.7 +/- 1.8 during dialysis with an LP membrane) versus 3.3 +/- 1 in healthy volunteers. Dialysis procedures with an HP or an LP membrane do not importantly modify the pharmacokinetics of reviparin compared with data observed in healthy volunteers. During the sessions, we observed no clotting in the extracorporeal circuit, no hemorrhagic event and no prolongation of the fistula compression times. Further clinical studies are required to define the optimal dosage of reviparine to prevent coagulation in hemodialysis blood circuits.

Elevated lipoprotein (a) levels in primary nephrotic syndrome.

Elevated plasma levels of total cholesterol and increase in the hepatic synthesis of some apo B-containing lipoproteins have been noted in the nephrotic syndrome. Apoprotein (a), the apolipoprotein distinguishing lipoprotein (a) [Lp(a)] from low-density lipoprotein, is equally of hepatic origin, and Lp(a) recently has been shown to possess both atherogenic and thrombogenic activities. However, little is known of Lp(a) levels in nephrotic patients. We measured plasma Lp(a) concentrations in 11 patients with primary nephrotic syndrome in the absence of hematuria, hypertension, and renal insufficiency. Histologic lesions were minimal-change disease in five cases, membranous glomerulopathy in four cases, and focal and segmental glomerulosclerosis in two cases. Mean levels of Lp(a) (98 +/- 92 mg/dL [mean +/- SD]) were markedly elevated in the nephrotic patients as compared with the controls (14 +/- 13 mg/dL). No correlation was noted between plasma Lp(a) and proteinuria, albuminemia, total cholesterolemia, low-density lipoprotein cholesterol, apoprotein B100, or plasminogen. Furthermore, there was no correlation between Lp(a) levels and apoprotein (a) isoform size. In four patients, the level of Lp(a) decreased approximately fourfold after remission of the nephrotic syndrome under corticosteroid treatment. Our observation that Lp(a) levels are elevated in the nephrotic syndrome is consistent with the hypothesis that these patients may be at an increased risk of cardiovascular and thrombotic complications.