Late-onset renal failure in Senior-Loken syndrome.

We report on four patients, from three different families, with Senior-Loken syndrome (SLS). They were unusual in that they reached end-stage renal failure (ESRF) only during the fifth or sixth decade. SLS is an autosomal-recessive disorder defined by the association of nephronophthisis and retinal dystrophy. Affected individuals invariably progress to ESRF, usually before the age of 20 years. The diagnosis was based on typical clinical presentation and characteristic renal histology, that is, a picture of chronic interstitial nephritis with pronounced thickening and multilayering of tubular basement membranes. Deterioration of renal function was slow, leading to ESRF between the ages of 42 and 56 years. Retinal dystrophy, already symptomatic during childhood in two patients, led to severe visual impairment in all. In contrast with four cases of SLS recently reported in very young patients, the NPH1 gene (the main gene responsible for nephronophthisis) was not deleted in our two tested patients. We conclude that SLS should be considered in adults who suffer from both chronic interstitial nephropathy and retinal degeneration. Whether the SLS is a variant of nephronophthisis and whether early- and late-onset renal failure in SLS is accounted for by genetic or allelic heterogeneity remain to be determined.

[Kinins: their nature and their potential role in the cardiovascular effects of angiotensin-converting enzyme inhibitors]. / Les kinines: leur nature et leur rôle potentiel dans les effets cardiovasculaires des inhibiteurs de l'enzyme de conversion de l'angiotensine.

The purpose of the present review dedicated to the kallikrein-kininogen-kinin system is to highlight the pathophysiological role of this complex system in kidney diseased patients. We will focus mainly on the nature of bradykinin and its active metabolite, des-Arg9-bradykinin. After the description of their properties, their metabolism and their receptors, we will show the recent evidence about the renal kallikrein-kinine system and its autocrin/paracrin role. This will allow to the nephrologist a better understanding of the role of these vasoactive peptides not only in the beneficial aspects, but also in the acute side-effects, of angiotensin-converting enzyme inhibitors.

Des-Arg9-bradykinin metabolism in patients who presented hypersensitivity reactions during hemodialysis: role of serum ACE and aminopeptidase P.

Bradykinin (BK) has been proposed as the principal mediator of hypersensitivity reactions (HSR) in patients dialyzed using negatively charged membranes and concomitantly treated with angiotensin-converting enzyme (ACE) inhibitors. We investigated the metabolism of exogenous BK added to the sera of 13 patients dialyzed on an AN69 membrane with a history of HSR (HSR+ patients) and 10 others who did not present such a reaction (HSR- patients) while dialyzed under the same conditions. No significant difference in the t1/2 of BK was found between the patient groups. However, the t1/2 of generated des-Arg9-BK was significantly increased (2.2-fold) in HSR+ patients compared to HSR-subjects. Preincubation of the sera with an ACE inhibitor (enalaprilat) significantly increased the t1/2 of both BK and des-Arg9-BK in both groups. There was no significant difference between the groups with respect to the t1/2 of BK, but there was a significantly greater increase (3.8-fold) in the t1/2 of des-Arg9-BK in HSR+ patients compared to HSR-subjects. The level of serum aminopeptidase P (APP) activity showed a significant decrease in the HSR+ sera when compared to HSR-samples. In HSR- and HSR+ patients, a significant inverse relation (r2 = 0.6271; P < 0.00005) could be calculated between APP activity and des-Arg9-BK t1/2. In conclusion, HSR in hemodialyzed patients who are concomitantly treated with a negatively charged membrane and an ACE inhibitor can be considered as a multifactorial disease in that a decreased APP activity resulting in reduced degradation of des-Arg9-BK may lead to the accumulation of this B1 agonist that could be responsible, at least in part, for the signs and symptoms of HSR.

Recurrent fulminant anti-glomerular basement membrane nephritis at a 7-year interval.

True recurrence of anti-glomerular basement membrane (anti-GBM) nephritis is very rare, both in native kidneys and after renal transplantation. We report the recurrence of fulminant anti-GBM nephritis in a kidney graft recipient after the spontaneous withdrawal of immunosuppressive treatment more than 5 years after renal transplantation. The initial episode of anti-GBM nephritis had destroyed the native kidneys 7 years earlier. Circulating anti-GBM antibodies had disappeared for 14 months at the time of transplantation and reappeared with recurrence. This observation challenges the concept of anti-GBM nephritis as a single-shot illness and emphasises the need to consider the possibility of recurrence, even in the long term, among patients who underwent transplantation for anti-GBM nephritis.

Molecular analysis of GB virus C isolates in Belgian hemodialysis patients.

GB virus C (GBV-C) has been detected in Belgian hemodialysis patients. To study their genomic diversity and phylogenetic relationship, a 592 nucleotide fragment extending from the 5' non-coding region to part of the E1 gene of the GBV-C genome was amplified and sequenced from 12 Belgian hemodialysis patients in two different centers. Together with strains from different geographical origins, these sequences were analyzed phylogenetically using three different methods. A consistent tree topology was obtained with all methods. Three GBV-C genotypes were observed with two subtypes in type 2 and a questionable subtyping in type 1. Except for one isolate falling into type 1 cluster which mainly consists of African strains, all the other Belgian strains clustered within the type 2a branch. Two GBV-C isolates in two patients from the same hemodialysis center clustered together closely, suggesting a nosocomial transmission. In view of their long branch length, it seems unlikely that the other Belgian strains evolved recently from a common ancestor. Our results indicate that the major type circulating among Belgian hemodialysis patients seems to be 2a, which is usual for Europe and North America, but that the African type 1 also exists to a minor extent. Although patient to patient transmission of GBV-C in Belgian hemodialysis centers did occur, it may not account for the majority of infections.

Hepatitis G virus infection in haemodialysed patients: epidemiology and clinical relevance.

BACKGROUND: The prevalence, incidence, risk factors, and clinical impact of infection by the recently discovered hepatitis G virus (HGV) in haemodialysed (HD) patients, are poorly defined. METHODS: All 119 HD patients from two Belgian units selected for their different hepatitis C virus (HCV) prevalences (A: 19.2%, B: 3.4%) were tested for the presence of HGV-RNA, using the reverse transcriptase polymerase chain reaction (RT-PCR) and primers from the 5'-NC and NS 5a genome regions. The results of anti-HCV antibodies and alamine aminotransferase levels (ALT) at the time of RT-PCR, number of transfusions from the onset of HD, and time on HD were retrieved from the medical charts. Forty patients were retested by RT-PCR 3-64 months later. RESULTS: HGV-RNA was detected with both sets of primers in 11/78 patients (14.1%) from centre A and 8/41 patients (19.5%) from centre B, for an average prevalence of 16%. One patient was indeterminate (positive with one set of primers). The presence of HGV-RNA correlated neither with time on HD (P = 0.18), nor with the number of transfusions on HD (P = 0.14). It was associated with the presence of anti-HCV antibodies in centre A (P < 0.01) but not B (P > 0.5). Twenty-seven initially negative (-) patients (A: n = 18; B: n = 9) were retested: two became positive (+) both in the absence of transfusions for years, giving a yearly incidence of 1.7%. The 13 initially HGV-RNA (+) patients remained so over time (33 patient-years). The presence of HGV-RNA alone does not increase significantly the ALT level, in contrast to the strong influence of HCV. CONCLUSION: The prevalence and yearly incidence of HGV infection are 16% and 1.7%, respectively, in our HD patients. Neither the number of transfusions on HD nor the time on HD are significant risk factors. Although mixed HCV/HGV infections indicate common risks, the prevalence of HCV in a particular setting does not predict prevalence of HGV. As new infections are detected in the absence of blood transfusions, HGV may be another marker of nosocomial viral transmission. Once acquired, the infection persists for many years in HD patients.

The influence of haemodialysis and haemofiltration on the clearance of torasemide in renal failure.

The concentration of Torasemide in plasma, dialysate and ultrafiltrate were determined during one haemofiltration and three dialyses. Results show that Torasemide is not significantly eliminated from the blood by these technics.