title: Novel unbiased assay for circulating podocyte-toxic factors associated with recurrent focal segmental glomerulosclerosis.
abstract: Focal segmental glomerular sclerosis (FSGS) is an irreversible renal pathology characterized by podocyte detachment from the glomerular basement membrane, hyalinosis, and sclerosis. Clinically, it manifests with proteinuria and progressive loss of glomerular filtration. Primary idiopathic FSGS can occur in isolation and frequently progresses to end-stage renal disease, requiring dialysis or kidney transplantation. In 30-50% of these patients, proteinuria and FSGS recur in the renal allograft, suggesting the presence of a podocyte-toxic factor(s) in the recipient's serum. Currently, there is no reliable way to quantify the serum activity or predict the subset of FSGS patients at risk for recurrence after transplantation. We describe a novel in vitro method that measures the podocyte-toxic activity of sera from FSGS patients using cultured human podocytes; we compare this with the effect of compounds such as adriamycin. Using immunofluorescence microscopy followed by computerized image-processing analysis, we show that incubation of human podocytes with adriamycin leads to a dose-dependent disassembly of focal adhesion complexes (FACs). We then demonstrate that sera from patients with posttransplant recurrent or idiopathic FSGS cause a similar FAC disturbance. In contrast, sera from nonrecurrent FSGS patients do not affect FACs. In some FSGS patients, toxic effects of serum can be prevented by blockade of the tumor necrosis factor-α pathway. We propose that this method may be useful as a diagnostic tool to identify FSGS patients with serum podocyte-toxic activity that presumably places them at increased risk for recurrence in the renal allograft.
authors.affiliation: Department of Medicine, McGill University and McGill University Health Center, Montreal, Quebec, Canada;
authors.forename: Nadezda
authors.initials: N
authors.lastname: Kachurina
authors.affiliation: Department of Medicine, McGill University and McGill University Health Center, Montreal, Quebec, Canada;
authors.forename: Chen-Fang
authors.initials: CF
authors.lastname: Chung
authors.affiliation: Department of Medicine, McGill University and McGill University Health Center, Montreal, Quebec, Canada;
authors.forename: Erin
authors.initials: E
authors.lastname: Benderoff
authors.affiliation: Department of Medicine, McGill University and McGill University Health Center, Montreal, Quebec, Canada;
authors.forename: Sima
authors.initials: S
authors.lastname: Babayeva
authors.affiliation: The Montreal Children's Hospital, Department of Paediatric Nephrology, McGill University Health Center, Montreal, Quebec, Canada;
authors.forename: Martin
authors.initials: M
authors.lastname: Bitzan
authors.affiliation: The Montreal Children's Hospital, Department of Paediatric Nephrology, McGill University Health Center, Montreal, Quebec, Canada; Department of Human Genetics, McGill University, Montreal, Quebec, Canada;
authors.forename: Paul
authors.initials: P
authors.lastname: Goodyer
authors.affiliation: Department of Human Genetics, McGill University, Montreal, Quebec, Canada;
authors.forename: Thomas
authors.initials: T
authors.lastname: Kitzler
authors.affiliation: McKinsey & Company, Washington, District of Columbia; and.
authors.forename: Dany
authors.initials: D
authors.lastname: Matar
authors.affiliation: Department of Medicine, McGill University and McGill University Health Center, Montreal, Quebec, Canada;
authors.forename: Andrey V
authors.initials: AV
authors.lastname: Cybulsky
authors.affiliation: Division of Nephrology, The Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Nada
authors.initials: N
authors.lastname: Alachkar
authors.affiliation: Department of Medicine, McGill University and McGill University Health Center, Montreal, Quebec, Canada; elena.torban@mcgill.ca.
authors.forename: Elena
authors.initials: E
authors.lastname: Torban
mesh_terms: D000293:Adolescent; D000328:Adult; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D004317:Doxorubicin; D005260:Female; D022001:Focal Adhesions / Q000187:drug effects*; D005923:Glomerulosclerosis, Focal Segmental / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D050199:Podocytes / Q000187:drug effects*; D012008:Recurrence; D015203:Reproducibility of Results; D018570:Risk Assessment; D014118:Toxins, Biological / Q000097:blood* / Q000633:toxicity; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D055815:Young Adult
chemical_list: D014118:Toxins, Biological; D014409:Tumor Necrosis Factor-alpha; D004317:Doxorubicin
keywords: idiopathic focal segmental glomerulosclerosis; renal allograft