Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Sirolimus induced phosphaturia

ABSTRACT: Introduction: The kidney is the major arbiter of extracellular phosphate homeostasis. The vast majority of glomerular filtrated phosphate is reabsorbed in the proximal tubule. Posttransplant phosphaturia is common and aggravated by sirolimus immunosuppression. The cause of sirolimus induced phosphaturia however remains elusive. Results: The urine phosphate/creatinine ratio was higher and serum phosphate was lower in sirolimus treated rats, fractional excretion of phosphate was elevated and renal tubular phosphate reabsorption was reduced suggesting a renal cause for hypophosphatemia. PTH was lower in sirolimus treated rats. FGF 23 levels were unchanged at day 2 but lower in sirolimus treated rats after 7 days. Brush border membrane vesicle phosphate uptake was not altered in sirolimus treated groups or by direct incubation with sirolimus. mRNA, protein abundance, and subcellular transporter distribution of NaPi-IIa, Pit-2 and NHE3 were not different between groups but NaPi-IIc mRNA expression was lower at day 7. Transcriptome analyses revealed candidate genes that could be involved in the phosphaturic response. Discussion: Sirolimus caused a selective renal phosphate leakage which was not mediated by NaPi-IIa or NaPi-IIc regulation or localization. We hypothesize that another mechanism such as a basolateral phosphate transporter may be responsible for the sirolimus induced phosphaturia. Male Wistar rats received sirolimus or vehicle for 7 days (1.5mg/kg) and were placed in individual metabolic cages for eight days allowing a 24 hour adaption period to the metabolic cage environment. At the end of the experiments rats were anesthetized by inhalation of Isoflurane/air and blood samples and kidneys were collected. 4 cases (sirolimus) and 4 controls (vehicle) have been analysed

ORGANISM(S): Rattus norvegicus

SUBMITTER: Julia Wilflingseder

PROVIDER: E-GEOD-35048 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Sirolimus induced phosphaturia is not caused by inhibition of renal apical sodium phosphate cotransporters.

Haller Maria M Amatschek Stefan S Wilflingseder Julia J Kainz Alexander A Bielesz Bernd B Pavik Ivana I Serra Andreas A Mohebbi Nilufar N Biber Jürg J Wagner Carsten A CA Oberbauer Rainer R

PloS one 20120730 7

The vast majority of glomerular filtrated phosphate is reabsorbed in the proximal tubule. Posttransplant phosphaturia is common and aggravated by sirolimus immunosuppression. The cause of sirolimus induced phosphaturia however remains elusive. Male Wistar rats received sirolimus or vehicle for 2 or 7 days (1.5mg/kg). The urine phosphate/creatinine ratio was higher and serum phosphate was lower in sirolimus treated rats, fractional excretion of phosphate was elevated and renal tubular phosphate r ...[more]

PMID: 22859939

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Project description:Background: Despite significant improvements in short-term kidney transplant survival, comparable increases in 5 and 10-year outcomes have not been achieved. Chronic allograft nephropathy (CAN) is a major cause of late graft loss. Toxic nephropathy and inadequate long-term immunosuppression are possible factors. We performed a randomized prospective trial comparing calcineurin inhibitor (CNI)-free to CNI-based immunosuppression to determine the impact on renal function, structure, and gene expression. Methods: Sixty-one kidney recipients received mycophenolate mofetil (MMF), and prednisone (P). Randomized patients received concentration-controlled sirolimus or cyclosporine. Two years post-transplant 55 patients underwent renal function studies, 48 (87%) underwent transplant biopsies; all classified by Banff scoring and 41 by DNA microarrays. Findings: Comparing sirolimus/MMF/P to cyclosporine/MMF/P at two years, there was a significantly lower serum creatinine (1.35 vs. 1.81 mg/dl; p=0.008), significantly higher Cockroft-Gault glomerular filtration rate (GFR) (80.4 vs. 63.4 cc/min; p=0.008), iothalamate GFR (60.6 vs. 49.2 cc/min; p= 0.018), and Banff 0 (normal) biopsies (66.6 vs. 20.8%; p=0.013). Regression analysis of calculated GFR’s from 1 to 36 months yielded a positive slope for sirolimus of 3.36 ml/min/year, and a negative slope for cyclosporine of –1.58 ml/min/year (p=0.008). Gene expression profiles of kidney biopsies with higher Banff CAN scores confirmed significant up regulation of genes responsible for immune/inflammation and fibrosis/tissue remodeling. Interpretation: At two years the sirolimus-treated patients have better renal transplant function, a diminished prevalence of CAN, and down regulated expression of genes responsible for the progression of CAN. All may provide for an alternative natural history with improved graft survival. Keywords = Cyclosporine Keywords = Sirolimus Keywords = Transplantation Keywords = DNA microarrays Keywords = calcineurin inhibitors Keywords: parallel sample. This dataset is part of the TransQST collection.

Dataset Information

Sirolimus induced phosphaturia

Publications

Sirolimus induced phosphaturia is not caused by inhibition of renal apical sodium phosphate cotransporters.

Similar Datasets

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