(1/817) Identification of DNA polymorphisms associated with the V type alpha1-antitrypsin gene.
alpha1-Antitrypsin (alpha1-AT) is a highly polymorphic protein. The V allele of alpha1-AT has been shown to be associated with focal glomerulosclerosis (FGS) in Negroid and mixed race South African patients. To identify mutations and polymorphisms in the gene for the V allele of alpha1-AT in five South African patients with FGS nephrotic syndrome DNA sequence analysis and restriction fragment length polymorphisms of the coding exons were carried out. Four of the patients were heterozygous for the BstEII RFLP in exon III [M1(Val213)(Ala213)] and one patient was a M1(Ala213) homozygote. The mutation for the V allele was identified in exon II as Gly-148 (GGG)-->Arg (AGG) and in all patients was associated with a silent mutation at position 158 (AAC-->AAT). The patient who was homozygous for (Ala213) also had a silent mutation at position 256 in exon III (GAT-->GAC) which was not present in any of the other four patients. Although the V allele of alpha1-AT is not associated with severe plasma deficiency, it may be in linkage disequilibrium with other genes on chromosome 14 that predispose to FGS. Furthermore, the associated silent mutation at position 158 and the Ala213 polymorphism are of interest, as these could represent an evolutionary intermediate between the M1(Ala213) and M1(Val213) subtypes. (+info)
(2/817) Predictive value of race in post-transplantation recurrence of focal segmental glomerulosclerosis in children.
BACKGROUND: Focal segmental glomerulosclerosis (FSGS) is a leading cause of end-stage renal disease (ESRD) in children, and one of the most difficult to manage because of its high recurrence rate post-transplantation (Tx). Several predictive factors have been associated with disease recurrence (DR) although one in particular, the role of recipient race, has not been adequately evaluated. Herein we report our experience with DR in the post-Tx period in eight patients. METHODS: Records were reviewed for all renal transplants performed at St Christopher's Hospital for Children from 1971 to 1997. RESULTS: Twenty patients received 27 allografts for ESRD due to FSGS. Ten (37%) grafts went to African-American (AA) children, and 16 (59%) to those of Caucasian (C) origin. DR was observed in eight (30%) grafts after Tx. No differences were noted between the patients who developed DR and those who did not, with respect to age at diagnosis or time to ESRD. DR was observed in one (10%) of 10 grafts in AA, compared to seven (41%) of 17 grafts in the other (O) racial groups (P=0.19). At last follow-up, the only AA recipient with DR has maintained stable renal function, while three (43%) of seven in O have lost their grafts. CONCLUSION: In conclusion, in our population post-Tx recurrence of FSGS occurred more frequently and represented a greater threat to graft survival in O recipients than in those of AA descent. Recipient race should therefore be taken into consideration during pre-Tx counselling of families of children with FSGS. (+info)
(3/817) Altered renal hemodynamics and impaired myogenic responses in the fawn-hooded rat.
The present study examined whether an abnormality in the myogenic response of renal arterioles that impairs autoregulation of renal blood flow (RBF) and glomerular capillary pressure (PGC) contributes to the development of renal damage in fawn-hooded hypertensive (FHH) rats. Autoregulation of whole kidney, cortical, and medullary blood flow and PGC were compared in young (12 wk old) FHH and fawn-hooded low blood pressure (FHL) rats in volume-replete and volume-expanded conditions. Baseline RBF, cortical and medullary blood flow, and PGC were significantly greater in FHH than in FHL rats. Autoregulation of renal and cortical blood flow was significantly impaired in FHH rats compared with results obtained in FHL rats. Myogenically mediated autoregulation of PGC was significantly greater in FHL than in FHH rats. PGC rose from 46 +/- 1 to 71 +/- 2 mmHg in response to an increase in renal perfusion pressure from 100 to 150 mmHg in FHH rats, whereas it only increased from 39 +/- 2 to 53 +/- 1 mmHg in FHL rats. Isolated perfused renal interlobular arteries from FHL rats constricted by 10% in response to elevations in transmural pressure from 70 to 120 mmHg. In contrast, the diameter of vessels from FHH rats increased by 15%. These results indicate that the myogenic response of small renal arteries is altered in FHH rats, and this contributes to an impaired autoregulation of renal blood flow and elevations in PGC in this strain. (+info)
(4/817) Nodular glomerulosclerosis with deposition of monoclonal immunoglobulin heavy chains lacking C(H)1.
The objective of this study was to further characterize the clinical and immunopathologic features of heavy chain deposition disease (HCDD), a recently described entity. Four patients were diagnosed as having HCDD on a kidney biopsy. All presented with nodular glomerulosclerosis with deposition of gamma1 heavy chains lacking CH1 epitopes, but without light chains. Two different patterns were observed in the serum. First, patients 1 and 2 had a circulating monoclonal IgGlambda containing a short gamma1 heavy chain lacking CH1 epitopes, with an apparent molecular weight of 40 kD consistent with a complete CH1 deletion. Biosynthetic experiments also showed that the deleted heavy chain was produced in excess compared with light chains, and was secreted in vitro together with half Ig molecules, although these abnormal components were not detected by Western blot analysis of whole serum. Second, patients 3 and 4 had a circulating monoclonal IgG1lambda with an apparently normal, nondeleted heavy chain subunit, but serum fractionation followed by immunoblotting revealed an isolated monoclonal gamma1 chain lacking CH1 epitopes. These data strongly suggest that renal deposition of a CH1-deleted heavy chain circulating in low amounts in the serum as a free unassembled subunit is a major feature of HCDD. The CH1 deletion is most likely responsible for the premature secretion in blood of the heavy chain by a clone of plasma cells. (+info)
(5/817) "The FSGS factor:" enrichment and in vivo effect of activity from focal segmental glomerulosclerosis plasma.
A circulating causative factor has been postulated in focal segmental glomerulosclerosis (FSGS). It has been shown that serum or plasma from some FSGS increases glomerular albumin permeability (Palb) in vitro. Palb greater than 0.5 (i.e., FS activity) is associated with recurrence after transplantation. Specimens from 15 FSGS patients were studied to document the presence of a permeability factor, to isolate this factor, to characterize its biochemical properties, and to show its effect in vivo. Total lipids were extracted by chloroform/methanol (2: 1); FS activity was absent from total lipid extract. Chylomicrons and lipoproteins were removed from the plasma with dextran sulfate, followed by sequential precipitation of proteins at 50 and 70% ammonium sulfate saturation. FS activity was retained in the 70% ammonium sulfate supernatant and exhibited a 100-fold purification. FS activity was lost after heating at 100 degrees C for 10 min or after protease digestion. Under nondenaturing conditions, electrophoresis of the FSGS 70% supernatant showed a prominent low molecular weight band that was not evident in the 70% supernatant from normal plasma. Dialysis and centrifugation-based membrane ultrafiltration of the FSGS factor indicated a molecular size between 30 and 50 kD. Injection of the 70% FSGS supernatant into rats caused a threefold increase in urine protein in collections from 6 to 24 h after injection. No increase in proteinuria occurred in rats injected with 70% supernatant from normal individuals. It is concluded that the FSGS factor is a low molecular weight protein with the potential to increase Palb in vitro and to cause proteinuria in vivo. (+info)
(6/817) Nature and severity of the glomerular response to nephron reduction is strain-dependent in mice.
Nephron reduction is an important factor in the development of glomerulosclerosis. In a study of the oligosyndactyly (Os) mutation that causes a congenital 50% reduction in nephron number, we previously found that ROP Os/+ mice developed glomerulosclerosis whereas C57B1/6J Os/+ mice did not. We concluded that the predisposition to glomerulosclerosis depended largely on the genetic background, the ROP being sclerosis-prone whereas the C57 strain was sclerosis-resistant. In the current experiments we asked whether the intensity of the sclerotic response to nephron reduction in the ROP strain was related to the time at which it occurred, ie, a pre- or post-natal event. We also determined whether the absence of lesions in C57 Os/+ mice was caused by a higher threshold for the induction of a sclerotic response in C57 mice. We further examined the relationship between glomerular hypertrophy and sclerosis. C57 +/+, C57 Os/+, ROP +/+, and ROP Os/+ mice were uninephrectomized (NX) at age 10 weeks and followed for 8 weeks. We found no sclerotic changes in NX C57 +/+ and C57 Os/+ mice, despite a 75% reduction in nephron number in the latter. In contrast, both NX ROP +/+ and NX ROP Os/+ mice had glomerulosclerosis, which was more severe in the NX ROP Os/+ mice. Examination of extracellular matrix synthesis and degradation at the mRNA level revealed that synthesis exceeded degradation in ROP Os/+ mice. The lesions in NX ROP +/+ were less severe than in sham-operated ROP/Os mice, suggesting that the timing of nephron reduction affected the amplitude of the sclerotic response in this strain. Following NX, an increase in glomerular volume was found in C57 +/+, ROP +/+, and ROP Os/+ mice. However, NX did not lead to a further increase in glomerular volume in C57 Os/+ mice. We make three conclusions: 1) sclerosis was more severe in the ROP strain when nephron reduction occurred in utero; 2) the absence of glomerulosclerosis in C57 mice was not related to a higher threshold for a sclerosis response in this strain; and 3) whereas glomerular size continued to increase as nephron number decreased in ROP mice, it reached a plateau in C57 mice. (+info)
(7/817) T lymphocyte subsets and cytokine production by graft-infiltrating cells in FSGS recurrence post-transplantation.
BACKGROUND: Focal segmental glomerulosclerosis (FSGS) aetiology remains undefined although a derangement of lymphocytes and monocytes macrophages, at least, has been strongly suspected. We report the graft-infiltrating phenotypes and their cytokine production in a case of FSGS recurrence post-transplantation. METHODS: The kidney transplant recipient suffered immediate FSGS recurrence. Aspiration biopsies were done at the first and second week post-surgery and were analysed by flow cytometry. The cytokine analysis was done on aspiration sample culture supernatants and serum by enzyme-linked immunosorbent assay. RESULTS: High expression of CD3CD69, CD3CD71 and CD4CD29 was found on infiltrating lymphocytes. Biopsy cultures pointed to a Th0/Th1 pattern of cytokine production as well as significant synthesis of transforming growth factor-beta1. Interestingly, monocyte chemokines were absent. CONCLUSION: We report evidence of intragraft lymphocyte activation in the early days of FSGS recurrence. Aspiration biopsy cultures showed failure of cyclosporin A to inhibit interleukin-2 (IL-2) production by infiltrating lymphocytes. If our findings are confirmed in similar patients, a trial with anti-IL-2-receptor antibody could be warranted. (+info)
(8/817) Clinical and genetic heterogeneity in familial focal segmental glomerulosclerosis. International Collaborative Group for the Study of Familial Focal Segmental Glomerulosclerosis.
BACKGROUND: Familial forms of focal segmental glomerulosclerosis (FFSGS) that exhibit autosomal dominant or recessive patterns of inheritance have been described. The genetic basis of these hereditary forms of FSGS is unknown. One recent study of a kindred from Oklahoma with an autosomal dominant form of FSGS linked this disease to a region of chromosome 19q. In addition, polymorphisms in a gene in this region on chromosome 19q13 have been linked to congenital nephrotic syndrome of the Finnish type. We have ascertained and characterized a large family with autosomal dominant FFSGS (Duke 6530). METHODS: Families were compared for clinical and genetic heterogeneity. To test for linkage of our family to this portion of chromosome 19, genomic DNA was isolated from 102 family members, and polymerase chain reaction was performed using eight microsatellite markers that spanned the area of interest on chromosome 19. Data were evaluated using two-point linkage analysis, multipoint analysis, and an admixture test. RESULTS: Linkage was excluded at a distance of +/- 5 to 10 CM for all markers tested with two-point log10 of the odds of linkage (LOD) scores and from an approximate 60 CM interval in this area of chromosome 19q via multipoint analysis. CONCLUSIONS: FSGS has been called the "final common pathway" of glomerular injury, as it is a frequent pathological manifestation with diverse etiologies. This diversity likely correlates with the genetic heterogeneity that we have established. Thus, our data demonstrate that there are at least two genes responsible for this disease, and there is genetic as well as clinical heterogeneity in autosomal dominant FSGS. (+info)