No description available.

Ischaemia/Reperfusion Injury (IRI) is the most common cause of acute kidney injury- a devastating clinical problem lacking any specific treatments to promote renal recovery. Macrophages (Mφ) are pleiotropic cells of the innate immune system, with roles spanning host defence, cytotoxicity, clearance of apoptotic cells and promotion of tissue repair. Mφ are also known to be important mediators of renal injury in other experimental models of renal disease including transplantation, obstruction and glomerulonephritis. This work sought to examine the role of Mφ in mediating renal IRI. Conditional renal Mφ and monocyte depletion prior to experimental IRI was achieved by administering diphtheria toxin to the CD11b-DTR transgenic animal. This had no impact on either renal function or structural injury. In contrast liposomal clodronate mediated Mφ depletion provided functional and structural protection from injury. Administration of exogenous apoptotic cells also protected renal function if delivered 24h prior to IRI. Immunodeficient SCID mice exhibited a protected injury phenotype after IRI, however derived no additional protection from the administration of either liposomal clodronate or i.v. apoptotic cells. These findings suggest that the protective phenotype must involve either lymphocyte populations or circulating antibody. Preliminary work demonstrates that SCID mice lack IgM natural antibody which deposits in the kidney in the first 30 minutes after IRI. It was also demonstrated that apoptotic cells bind IgM natural antibody present within the circulation. The potential for the key antioxidant enzyme Heme oxygenase-1 (HO-1) to protect renal function was also examined in aged mice using hemearginate (HA) - a potent HO-1 inducer. Echoing epidemiological studies in humans aged mice had increased susceptibility to IRI, whilst failing to induce medullary HO-1. The main site of medullary HO-1 induction by HA was in medullary Mφ, and the protective phenotype was abolished by Mφ ablation, implicating Mφ as the key mediators of HA induced protection in renal IRI. Final studies employed adenoviral transduction to overexpress HO-1 within bone marrow derived Mφ, leading to a modified phenotype with increased IL- 10 and phagocytosis, and reduced TNFα and NO production. When these were introduced in vivo after IRI renal function was improved, potentially due to accelerated clearance of renal platelet deposition.

Renal ischemia/reperfusion (I/R) is a main cause of acute kidney injury (AKI) and delayed graft function after renal transplantation. Previous studies in human and experimental models have identified that inflammation and oxidative stress are two key players in renal I/R injury. However, the underlying mechanisms remain speculative. The overall objective of the study was to investigate the biochemical and molecular mechanisms of I/R-induced renal injury and the effect of tyrosol supplementation on I/R-induced kidney oxidative stress damage. In the present study, renal I/R was induced in Sprague-Dawley rats and in a human kidney proximal tubular cell line. A significantly elevated expression of pro-inflammatory cytokine expression (MCP-1, IL-6) was observed. There was a significant decrease in mRNA and protein levels of two hydrogen sulphide (H2S)-producing enzymes, CBS and CSE, with a concomitant reduction of glutathione and H2S production. In the cell culture model, hypoxia–reoxygenation of proximal tubular cells led to a decrease in CBS and CSE expression and an increase in pro-inflammatory cytokine expression. Supplementation of glutathione or H2S donor (NaHS) effectively abolished cytokine expression in tubular cells. Experiments were conducted to detect oxidative stress markers. It was demonstrated that there was a significant increase in peroxynitrite formation and lipid peroxidation in the kidney after I/R insult, which might be caused by the elevation in nitric oxide (NO) metabolites and inducible nitric oxide synthase (iNOS). Administration of tyrosol, a natural phenolic compound, reduced peroxynitrite formation, lipid peroxidation and the level of NO metabolites via inhibiting NF-B activation and iNOS expression. Tyrosol treatment improved kidney function and had a protective effect against I/R-induced AKI. The present study has clearly demonstrated that (1) there is a reduction of H2S production via inhibition of CBS and CSE expression, which contributes to increased pro-inflammatory cytokine expression in the kidney and in tubular cells upon I/R insult; (2) restoration of endogenous H2S production would be of therapeutic value in regulating inflammatory response in I/R-induced kidney injury; (3) tyrosol treatment has a beneficial effect against renal I/R-induced oxidative stress, in part, through its inhibition on NF-B activation and iNOS-mediated NO production. / May 2016

Background: Acute kidney injury (AKI) is a highly prevalent clinical disorder with significant mortality and no current treatment. The Burns Lab has previously shown that endothelial colony forming cells (ECFCs) release exosomes highly enriched in pro-survival micro-RNA-486-5p. In our mouse model of AKI, intravenous (i.v.) injection of ECFCs or their exosomes protects against kidney ischemic injury, associated with reduction in PTEN, a target of miR-486-5p. Mechanisms mediating recruitment and retention of exosomes are unclear. The interaction of CXC chemokine receptor type 4 (CXCR4) with stromal cell-derived factor (SDF)-1α promotes ECFC adhesion and migration in hypoxic endothelial cells. Whether exosomal miR-486-5p is critical to the prevention of ischemic injury is unclear. The current study aimed to investigate biodistribution and targeting mechanisms of ECFC-derived exosomes, to investigate the delivery and therapeutic potential of miR-486-5p alone, and to determine whether sex differences alter the treatment efficacy. Methods: ECFC-derived exosomes were isolated from cultured media by differential centrifugation and characterized using nanoparticle tracking analysis and immunoblot. Kidney ischemic injury was induced in male and female FVB mice by bilateral renal vascular clamping (30 min). Exosomes (20 µg) or Invivofectamine-mimic complex containing miR-486-5p (1mg/kg) were injected at the start of kidney reperfusion via tail vein. Organs were removed and assays were performed to identify structure and function. In vitro cell studies were also used when necessary. Results: ECFC-derived exosomes preferentially target the ischemic kidney, its endothelium and tubular epithelium, which correlates with increases in miR-486-5p. The transfer of exosomes may be mediated by macropinocytosis by target cells. The SDF-1α/CXCR4 axis plays a role in targeting exosomes to the site of injury. miR-486-5p alone has a similar therapeutic efficacy in preventing ischemia/reperfusion injury as ECFC-exosomes in the mouse model of AKI. Both male and female mice respond to both therapies, however female mice are protected against ischemia reperfusion injury. Conclusions: These results suggest that the protective effects of ECFCs or their exosomes in ischemic AKI may be largely mediated by pro-survival miR-486-5p. These data provide further support for the promising therapeutic potential of ECFC-derived exosomes and miR-486-5p in human AKI.

PURPOSE: Doppler renal resistive index (RRI) has emerged in the last decade as a useful prognostic indicator for transient (fluid responsive) and persistent acute kidney injury (AKI). The determinants of RRI are largely systemic and recent studies confirm that RRI measurement could also be a useful early marker for sub-clinical AKI and post procedural AKI risk. This study aimed to determine the feasibility of RRI measurement in an Emergency Department (ED) resuscitation room setting using a point­of­care ultrasound system. METHODS: In this prospective single centre study, RRI measurement was attempted in 20 non-consecutive patients (meeting the inclusion criteria) by a single expert sonographer. RRI measurements were evaluated against context specific feasibility criteria and target outcomes. RESULTS: 20 patients (11 male, 9 female) were recruited to the study. Age of patients ranged from 33 years to 91 years (mean 62.3 years). Adequate visualisation of both kidneys was achieved in 60% of patients (n=12). In patients where it was not possible to achieve adequate views of both kidneys (n=8), limiting technical factors were shortness of breath (SOB) (n=6), high BMI (n=2). At least one measurement of RRI was achieved in 70% of patients (n=14). However, in 9 of these patients (64.3%) the Doppler spectral traces achieved were substandard and did not meet the measurement criteria for RRI as specified in the study protocol. In 30% of patients (n=6) no usable spectral trace was achieved and it was not possible to measure RRI. SOB was noted as a technical difficulty in 60% of patients (n=12) including three for whom RRI measurements were achieved. In 9 patients (45%) SOB was recorded as the primary reason for failure to acquire a usable Doppler trace. All criteria for RRI measurements were met in only 3 patients (15%). CONCLUSION: Measurement of RRI was not feasible in patients requiring resuscitation room care using a current point of care ultrasound system. If RRI is to play a useful role in this high priority patient group, adaptation of the available technology is required to mitigate the problem of image blur due to patient breathing movement.

No description available.

Mitofusin 2 (MFN2), an outer mitochondrial membrane protein expressed in virtually all human tissues, is a multi-faceted protein known to affect mitochondrial morphology, metabolism, tethering, and movement as well as overall cell cycle progression. Most intriguing among its characteristics is its ability to bind to Ras and Raf, upstream effectors in the MAPK/ERK pathway. Conditional knockout (cKO) of renal proximal tubule MFN2 in vivo showed a post-ischemic protective effect. While the two day survival of control mice was only 28%, an unexpected 86% of the MFN2 cKO mice were alive at two days post-ischemia. This is likely explained by MFN2's ability to bind and sequester Ras at baseline. Because the MFN2 deficient mice did not sequester as much Ras, renal proximal tubule cells were able to proliferate at a greater rate and restore organ function more quickly. Immunoprecipitation studies confirm a strong interaction between Ras and MFN2 in resting cells but a weaker one immediately following ischemic insult, even in cells replete with MFN2. These results suggest that blocking the MFN2-Ras interaction may be a novel method to treat acute kidney injury. A small peptide mimicking Ras to block MFN2 could be feasible. This should grant ischemic tissue an increased propensity to regenerate healthy cells while leaving non-ischemic tissue completely unaffected. Such a therapeutic agent would be novel in the treatment of acute kidney injury and may have uses in other tissues as well due to MFN2's widespread expression profile.

Orientador: André Luís Balbi / Banca: Daniela Ponce / Banca: Denice Mafra / Resumo: É consenso na literatura que a desnutrição é freqüente em pacientes hospitalizados, devido principalmente a patologias que aumentam o risco nutricional, tais como a Injúria Renal Aguda (IRA). Sendo assim, a avaliação do estado nutricional nessa condição clínica torna-se uma ferramenta fundamental para a identificação de possíveis distúrbios nutricionais. Os objetivos deste trabalho foram realizar avaliação nutricional inicial e identificar, a partir desta, marcadores clínicos e nutricionais associados ao óbito em pacientes com IRA. Tratou-se de estudo prospectivo transversal realizado no Hospital das Clínicas da Faculdade de Medicina de Botucatu - UNESP no período de março de 2008 até março de 2010. Logo após a primeira avaliação nefrológica, foi realizada uma avaliação nutricional composta por dados clínicos, inquérito alimentar, balanço nitrogenado, antropometria, bioimpedância, Avaliação Subjetiva Global (ASG) e exames laboratoriais, tendo como desfecho o óbito. Foram avaliados 278 pacientes, com predomínio do sexo masculino e maiores de 60 anos, com mortalidade de 39,9%. Na análise multivariada, sepse, oligúria e necessidade de diálise estiveram associados a maior mortalidade. Quanto às características nutricionais e antropométricas, maior metabolismo basal, uso de dieta oral comparada ao jejum e maior ângulo de fase foram variáveis associadas a menor mortalidade, enquanto o uso de dieta parenteral comparada ao jejum, maiores valores de uréia e fósforo e menores valores de creatinina e albumina estiveram associados a maior mortalidade. Em conclusão, a partir da avaliação nutricional inicial, este estudo identificou variáveis associadas ao óbito que podem ser úteis no acompanhamento nefrológico de pacientes com IRA / Abstract: There is consensus in the literature that malnutrition is frequent in hospitalized patients, mainly due to the presence of pathologies that increase the nutritional risk, such as Acute Kidney Injury (AKI), and thus the assessment of nutritional status in that clinical condition makes a fundamental tool for the identification of possible nutritional disorders. The objectives of this research were to realize initial nutritional assessment and identify, from this, clinical and nutritional markers associated with death in these patients. This was a transversal prospective study with patients with AKI, admitted to the HC-FMBUNESP of March 2008 until March 2010. Immediately after the first nephrology evaluation, was applied a nutritional assessment composed of clinical data, food investigation, nitrogen balance (NB), anthropometry, bioelectrical impedance, Subjective Global Assessment (SGA) and laboratory values, taking death as outcome. Were evaluated 278 patients, with predominance of males with a mortality of 39.9%. In the multivariate analysis, sepsis, oliguria and requirement dialysis were associated with greater mortality. As regards the nutritional and anthropometric characteristics, negative NB was present in 69.2% of the population. The other multivariate analyzes showed that greater basal metabolism, use of oral diet compared to fasting and greater phase angle were variables associated with lower mortality, while the use of diet parenteral compared to fasting, higher values of urea and phosphorus and lower creatinine and albumin were associated with greater mortality. In conclusion, from the initial nutritional assessment of patients with AKI, this study identified nutritional variables related to death, which must be assessed together with clinical variables, by nephrologist / Mestre

Made available in DSpace on 2014-06-11T19:25:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-21Bitstream added on 2014-06-13T20:14:15Z : No. of bitstreams: 1 pinto_mpr_me_botfm.pdf: 313356 bytes, checksum: 0e7af8768f28717e8fc720462d87afa7 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / É consenso na literatura que a desnutrição é freqüente em pacientes hospitalizados, devido principalmente a patologias que aumentam o risco nutricional, tais como a Injúria Renal Aguda (IRA). Sendo assim, a avaliação do estado nutricional nessa condição clínica torna-se uma ferramenta fundamental para a identificação de possíveis distúrbios nutricionais. Os objetivos deste trabalho foram realizar avaliação nutricional inicial e identificar, a partir desta, marcadores clínicos e nutricionais associados ao óbito em pacientes com IRA. Tratou-se de estudo prospectivo transversal realizado no Hospital das Clínicas da Faculdade de Medicina de Botucatu – UNESP no período de março de 2008 até março de 2010. Logo após a primeira avaliação nefrológica, foi realizada uma avaliação nutricional composta por dados clínicos, inquérito alimentar, balanço nitrogenado, antropometria, bioimpedância, Avaliação Subjetiva Global (ASG) e exames laboratoriais, tendo como desfecho o óbito. Foram avaliados 278 pacientes, com predomínio do sexo masculino e maiores de 60 anos, com mortalidade de 39,9%. Na análise multivariada, sepse, oligúria e necessidade de diálise estiveram associados a maior mortalidade. Quanto às características nutricionais e antropométricas, maior metabolismo basal, uso de dieta oral comparada ao jejum e maior ângulo de fase foram variáveis associadas a menor mortalidade, enquanto o uso de dieta parenteral comparada ao jejum, maiores valores de uréia e fósforo e menores valores de creatinina e albumina estiveram associados a maior mortalidade. Em conclusão, a partir da avaliação nutricional inicial, este estudo identificou variáveis associadas ao óbito que podem ser úteis no acompanhamento nefrológico de pacientes com IRA / There is consensus in the literature that malnutrition is frequent in hospitalized patients, mainly due to the presence of pathologies that increase the nutritional risk, such as Acute Kidney Injury (AKI), and thus the assessment of nutritional status in that clinical condition makes a fundamental tool for the identification of possible nutritional disorders. The objectives of this research were to realize initial nutritional assessment and identify, from this, clinical and nutritional markers associated with death in these patients. This was a transversal prospective study with patients with AKI, admitted to the HC-FMBUNESP of March 2008 until March 2010. Immediately after the first nephrology evaluation, was applied a nutritional assessment composed of clinical data, food investigation, nitrogen balance (NB), anthropometry, bioelectrical impedance, Subjective Global Assessment (SGA) and laboratory values, taking death as outcome. Were evaluated 278 patients, with predominance of males with a mortality of 39.9%. In the multivariate analysis, sepsis, oliguria and requirement dialysis were associated with greater mortality. As regards the nutritional and anthropometric characteristics, negative NB was present in 69.2% of the population. The other multivariate analyzes showed that greater basal metabolism, use of oral diet compared to fasting and greater phase angle were variables associated with lower mortality, while the use of diet parenteral compared to fasting, higher values of urea and phosphorus and lower creatinine and albumin were associated with greater mortality. In conclusion, from the initial nutritional assessment of patients with AKI, this study identified nutritional variables related to death, which must be assessed together with clinical variables, by nephrologist

Introduction: Patients with acute kidney injury (AKI) in developing countries are described in a profile of young age, with less comorbidities, with unifactorial, and with a lower mortality compared to patients in developed countries. Objective: To assess mortality in patients with acute kidney injury undergoing hemodialysis (HD) and its associated factors in a developing country setting. Methods: Retrospective study. Demographic, clinical, and mortality variables were collected from patients who presented AKI and underwent HD between January 2014 and December 2015 at a national reference hospital in Lima, Peru. Risk ratios (RR) and 95% confidence intervals (95%CI) were estimated through Poisson regressions. Results: Data from 72 patients with AKI that underwent HD were analyzed, 66.7% of them were < 64 years old, and 40.2% of all patients died undergoing HD. Crude analysis showed higher mortality among those who used vasopressors, but lower mortality among those with creatinine values > 8.9 mg/ dL. The adjusted analysis showed that having had a creatinine level of > 8.9 mg/ dL, compared to a creatinine level of < 5.2 mg/dL at the time of initiating HD, was associated with 74% less probability of death. Conclusion: Four out of every ten AKI patients undergoing HD die. Higher levels of creatinine were associated with lower probability of mortality.