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Renal Tubular Cell Mitochondrial Dysfunction Occurs Despite Preserved Renal Oxygen Delivery in Experimental Septic Acute Kidney Injury.

ABSTRACT: OBJECTIVE:To explain the paradigm of significant renal functional impairment despite preserved hemodynamics and histology in sepsis-induced acute kidney injury. DESIGN:Prospective observational animal study. SETTING:University research laboratory. SUBJECTS:Male Wistar rats. INTERVENTION:Using a fluid-resuscitated sublethal rat model of fecal peritonitis, changes in renal function were characterized in relation to global and renal hemodynamics, and histology at 6 and 24 hours (n = 6-10). Sham-operated animals were used as comparison (n = 8). Tubular cell mitochondrial function was assessed using multiphoton confocal imaging of live kidney slices incubated in septic serum. MEASUREMENTS AND MAIN RESULTS:By 24 hours, serum creatinine was significantly elevated with a concurrent decrease in renal lactate clearance in septic animals compared with sham-operated and 6-hour septic animals. Renal uncoupling protein-2 was elevated in septic animals at 24 hours although tubular cell injury was minimal and mitochondrial ultrastructure in renal proximal tubular cells preserved. There was no significant change in global or renal hemodynamics and oxygen delivery/consumption between sham-operated and septic animals at both 6- and 24-hour timepoints. In the live kidney slice model, mitochondrial dysfunction was seen in proximal tubular epithelial cells incubated with septic serum with increased production of reactive oxygen species, and decreases in nicotinamide adenine dinucleotide and mitochondrial membrane potential. These effects were prevented by coincubation with the reactive oxygen species scavenger, 4-hydroxy-2,2,6,6-tetramethyl-piperidin-1-oxyl. CONCLUSIONS:Renal dysfunction in sepsis occurs independently of hemodynamic instability or structural damage. Mitochondrial dysfunction mediated by circulating mediators that induce local oxidative stress may represent an important pathophysiologic mechanism.

SUBMITTER: Arulkumaran N

PROVIDER: S-EPMC5856355 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature

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Renal Tubular Cell Mitochondrial Dysfunction Occurs Despite Preserved Renal Oxygen Delivery in Experimental Septic Acute Kidney Injury.

Arulkumaran Nishkantha N Pollen Sean S Greco Elisabetta E Courtneidge Holly H Hall Andrew M AM Duchen Michael R MR Tam Frederick W K FWK Unwin Robert J RJ Singer Mervyn M

Critical care medicine 20180401 4

<h4>Objective</h4>To explain the paradigm of significant renal functional impairment despite preserved hemodynamics and histology in sepsis-induced acute kidney injury.<h4>Design</h4>Prospective observational animal study.<h4>Setting</h4>University research laboratory.<h4>Subjects</h4>Male Wistar rats.<h4>Intervention</h4>Using a fluid-resuscitated sublethal rat model of fecal peritonitis, changes in renal function were characterized in relation to global and renal hemodynamics, and histology at ...[more]

PMID: 29293148

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Project description:Simple Summary We studied survivors of childhood cancer who received cancer treatment that might affect the kidneys and compared them to controls from the general population. We investigated if there was a difference in the occurrence of tubular dysfunction. The tubules are the part of the kidney responsible for reabsorption of needed substances to the blood and the removal of wastes. After around 25 years since their cancer diagnosis, we found that in general there were no differences between survivors and controls, but survivors more often had losses of small proteins in the urine. Yet, some survivors of childhood cancer were found to have an increased risk of tubular dysfunction. Namely, survivors treated with the chemotherapeutic agents ifosfamide, cisplatin or carboplatin. Therefore, these patients should be monitored during their follow-up. Abstract The aim of this nationwide cross-sectional cohort study was to determine the prevalence of and risk factors for tubular dysfunction in childhood cancer survivors (CCS). In the DCCSS-LATER 2 Renal study, 1024 CCS (≥5 years after diagnosis), aged ≥ 18 years at study, treated between 1963 and 2001 with potentially nephrotoxic therapy (i.e., nephrectomy, abdominal radiotherapy, total body irradiation, cisplatin, carboplatin, ifosfamide, high-dose cyclophosphamide, or hematopoietic stem cell transplantation) participated, and 500 age- and sex-matched participants from Lifelines acted as controls. Tubular electrolyte loss was defined as low serum levels (magnesium < 0.7 mmol/L, phosphate < 0.7 mmol/L and potassium < 3.6 mmol/L) with increased renal excretion or supplementation. A α1-microglobulin:creatinine ratio > 1.7 mg/mmol was considered as low-molecular weight proteinuria (LMWP). Multivariable risk analyses were performed. After median 25.5 years follow-up, overall prevalence of electrolyte losses in CCS (magnesium 5.6%, potassium 4.5%, phosphate 5.5%) was not higher compared to controls. LMWP was more prevalent (CCS 20.1% versus controls 0.4%). LMWP and magnesium loss were associated with glomerular dysfunction. Ifosfamide was associated with potassium loss, phosphate loss (with cumulative dose > 42 g/m2) and LMWP. Cisplatin was associated with magnesium loss and a cumulative dose > 500 mg/m2 with potassium and phosphate loss. Carboplatin cumulative dose > 2800 mg/m2 was associated with potassium loss. In conclusion, long-term tubular dysfunction is infrequent. Yet, ifosfamide, cisplatin and carboplatin are risk factors.

Project description:AimsDespite advances in heart failure (HF) treatment, HF with preserved ejection fraction (HFpEF) remains a health problem with a high mortality rate. HFpEF is composed of diverse phenogroups, of which patients with concomitant renal impairment have worse outcomes. Renal tubular damage (RTD) is associated with the development of HF and chronic kidney disease (CKD). However, the impact of RTD on HF progression in patients with HFpEF and CKD remains unclear. The aim of the present study was to examine whether RTD could predict HF-related events in patients with HFpEF and CKD.Methods and resultsWe measured RTD markers, such as urinary β2 -microglobulin to creatinine ratio (UBCR) and N-acetyl-β-d-glucosamidase (NAG) level, in 319 consecutive patients with HFpEF and CKD who were hospitalized for acute HF (49% females, mean age 76 ± 12). Based on previous reports, high UBCR and high NAG levels were defined as UBCR ≥300 μg/gCr and NAG >14.2 U/gCr, respectively. There were 91 HF-related events, defined as HF hospitalizations or HF deaths, during the median follow-up period of 5.2 years. The prevalence of high UBCR increased with advancing New York Heart Association functional class and albuminuria. Kaplan-Meier analysis demonstrated that patients with high UBCR had more HF-related events than those with normal or low UBCR. Multivariate Cox proportional hazards regression analyses demonstrated that high UBCR, but not high NAG level, was an independent predictor of HF-related events after adjusting for confounding risk factors in patients with HFpEF and CKD (hazard ratio, 2.60; 95% confidence interval, 1.52-4.72; P = 0.0009). UBCR significantly improved the C-statistic, with a significant net reclassification index and integrated discrimination improvement (0.738 vs. 0.684; P = 0.0244).ConclusionRTD, as assessed by a high UBCR, was associated with the severity and clinical outcomes of HFpEF and CKD, indicating that it could be a feasible marker for HF progression.

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Dataset Information

Renal Tubular Cell Mitochondrial Dysfunction Occurs Despite Preserved Renal Oxygen Delivery in Experimental Septic Acute Kidney Injury.

Publications

Renal Tubular Cell Mitochondrial Dysfunction Occurs Despite Preserved Renal Oxygen Delivery in Experimental Septic Acute Kidney Injury.

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