SGLT-2 inhibitors in diabetes: a focus on renoprotection

SUMMARY Type 2 diabetes mellitus is an important public health problem, with a significant impact on cardiovascular morbidity and mortality and an important risk factor for chronic kidney disease. Various hypoglycemic therapies have proved to be beneficial to clinical outcomes, while others have failed to provide an improvement in cardiovascular and renal failure, only reducing blood glucose levels. Recently, sodium-glucose cotransporter-2 (SGLT2) inhibitors, represented by the empagliflozin, dapagliflozin, and canagliflozin, have been showing satisfactory and strong results in several clinical trials, especially regarding the reduction of cardiovascular mortality, reduction of hospitalization due to heart failure, reduction of albuminuria, and long-term maintenance of the glomerular filtration rate. The benefit from SGLT2 inhibitors stems from its main mechanism of action, which occurs in the proximal tubule of the nephron, causing glycosuria, and a consequent increase in natriuresis. This leads to increased sodium intake by the juxtaglomerular apparatus, activating the tubule glomerular-feedback and, finally, reducing intraglomerular hypertension, a frequent physiopathological condition in kidney disease caused by diabetes. In addition, this class of medication presents an appropriate safety profile, and its most frequently reported complication is an increase in the incidence of genital infections. Thus, these hypoglycemic agents gained space in practical recommendations for the management of type 2 diabetes mellitus and should be part of the initial therapeutic approach to provide, in addition to glycemic control, cardiovascular outcomes, and the renoprotection in the long term.

Expression of V2R and AQPs in the renal medulla of high-fat nutritional obesity of rat / Expresión de V2R y AQPs en la médula renal de ratas con obesidad nutricional alta en grasas

Recent evidence has indicated that adipose tissue produces bioactive substances that contribute to obesity-related kidney disease, altering the renal function and structure. Eight of the AQPs are expressed in the kidney, where several of them contribute to water absorption and maintenance of body water balance. In the study, we mainly examined the localization of AQP2, AQP3 and V2R in renal medulla of Normal Diet (ND) and High-fat Diet (HFD) of rats, respectively. In renal medulla of HFD, immunolight microscopy revealed weak expression of AQP2 at the apical plasma membrane and intracellular vesicles of principal cells of the IMCD and OMCD. AQP3 and V2R expression also observed a decrease in immunolabelling in the IMCD and OMCD. It was suggested that excess lipid accumulation may lead to lipotoxicity and may be the major driver of organ dysfunction such as water reabsorption dysfunction, which may be resulted from abnormal response of rphan G-protein-coupled receptors in kidney.

La evidencia reciente ha indicado que el tejido adiposo produce sustancias bioactivas que contribuyen a la enfermedad renal relacionada con la obesidad, alterando la función y la estructura renal. Ocho de los AQP se expresan en el riñón, donde varios de ellos contribuyen a la absorción de agua y al mantenimiento del equilibrio hídrico corporal. En el estudio, examinamos principalmente la localización de AQP2, AQP3 y V2R en la médula renal de ratas con dieta normal (ND) y ratas con dieta alta en grasas (HFD). En la médula renal del grupo HFD, la microscopía electrónica de barrido reveló una expresión débil de AQP2 en la membrana plasmática apical y las vesículas intracelulares de las células principales de IMCD y OMCD. La expresión de AQP3 y V2R también observó una disminución en el inmunomarcador en IMCD y OMCD. Se sugiere que el exceso de acumulación de lípidos puede conducir a lipotoxicidad y ser el principal impulsor de la disfunción orgánica, como la disfunción de reabsorción de agua, que puede ser el resultado de la respuesta anormal de los receptores acoplados a proteína rphan G en el riñón.

High prevalence of methicillin resistance and PVL genes among Staphylococcus aureus isolates from the nares and skin lesions of pediatric patients with atopic dermatitis

Staphylococcus aureus is highly prevalent among patients with atopic dermatitis (AD), and this pathogen may trigger and aggravate AD lesions. The aim of this study was to determine the prevalence of S. aureus in the nares of pediatric subjects and verify the phenotypic and molecular characteristics of the isolates in pediatric patients with AD. Isolates were tested for antimicrobial susceptibility, SCCmec typing, and Panton-Valentine Leukocidin (PVL) genes. Lineages were determined by pulsed-field gel electrophoresis and multilocus sequence typing (MLST). AD severity was assessed with the Scoring Atopic Dermatitis (SCORAD) index. Among 106 patients, 90 (85%) presented S. aureus isolates in their nares, and 8 also presented the pathogen in their skin infections. Two patients had two positive lesions, making a total of 10 S. aureus isolates from skin infections. Methicillin-resistant S. aureus (MRSA) was detected in 24 (26.6%) patients, and PVL genes were identified in 21 (23.3%), including 6 (75%) of the 8 patients with skin lesions but mainly in patients with severe and moderate SCORAD values (P=0.0095). All 24 MRSA isolates were susceptible to trimethoprim/sulfamethoxazole, while 8 isolates had a minimum inhibitory concentration (MIC) to mupirocin >1024 μg/mL. High lineage diversity was found among the isolates including USA1100/ST30, USA400/ST1, USA800/ST5, ST83, ST188, ST718, ST1635, and ST2791. There was a high prevalence of MRSA and PVL genes among the isolates recovered in this study. PVL genes were found mostly among patients with severe and moderate SCORAD values. These findings can help clinicians improve the therapies and strategies for the management of pediatric patients with AD.

Metabolismo mineral en niños en diálisis peritoneal crónica / Mineral metabolism in patients on chronic peritoneal dialysis

Introduction: Children with chronic kidney disease (CKD) and receiving peritoneal dialysis (PD) have disorders of mineral metabolism that impact their growth, survival and cardiovascular functions. New molecular markers offer a better understanding of the pathophysiology of this disease. Objective: To characterize some components of mineral metabolism, with emphasis on FGF23/Klotho and cardiovascular functions (CV) of these patients. Patients and Method: Prospective observational cohort study. Exclusion criteria: serum 25 (OH) vitamin D < 20 ng/ml, peritonitis within the last two months and active nephrotic syndrome. Calcemia, phosphemia, parathyroid hormone (PTH), 25 (OH) vitD3, 1.25 (OH) vitD3, FGF23 and Klotho in plasma were measured. FGF23 and Klotho were quantified in healthy children as a control group. Echocardiography was performed calculating the left ventricular mass index (LVMI). Descriptive statistics analysis, Pearson correlation coefficient for association among variables and multivariate analysis were conducted. Results: 33 patients, 16 males, aged between 1.2 and 13.4 years were included. Age of onset for PD: 7.3 +/- 5.0 years, time receiving PD: 13.5 +/- 14.5 months. The plasma concentration of 25 (OH) vitD3 was 34.2 +/- 6.3 pg/ml. Calcemia and phosphemia values were 9.8 ± 0.71 and 5.4 +/- 1.0 mg/dl respectively. PTH was 333 +/- 287 pg/ml. FGF23 in plasma was 225.7 +/- 354.3 pg/ml and Klotho 131.6 +/- 72 pg/ml, and in the controls ( n = 16 ), it was 11.9 +/- 7.2 pg/ml and 320 +/- 119 pg/ml, respectively. The residual and total dose of dialysis (KtV) was 1.6 +/- 1.3 and 2.9 +/- 1.6, respectively. FGF23 levels significantly correlated with calcium (p < 0.001, r = 0.85), and inversely with residual KtV, showing no relationship with phosphemia. Klotho level correlated negatively with residual KtV and also, it showed a negative association with chronological age and age at onset of PD. LVMI > 38 g/m² was confirmed in 20/28 patients...

Introducción: Los niños portadores de Enfermedad renal crónica (ERC) en diálisis peritoneal (DP) presentan alteraciones del metabolismo mineral que afectan su crecimiento, estado cardiovascular y sobrevida. Nuevos marcadores moleculares representan una mejor comprensión de la fisiopatología de esta enfermedad. Objetivo: Caracterizar componentes del metabolismo mineral, con énfasis en FGF23/Klotho, y estado cardiovascular (CV) en este grupo de pacientes. Pacientes y Método: Estudio prospectivo observacional. Criterios de exclusión: niveles de 25 (OH) vitamina D < 20 ng/ml, peritonitis hasta 2 meses previos y síndrome nefrótico activo. Se midió calcemia, fosfemia, paratohormona (PTH), 25 (OH) vitD3, 1,25 (OH) vitD3, FGF23 y Klotho en plasma. Se cuantificó FGF23 y Klotho en niños sanos como grupo control. Se efectuó ecocardiografía, calculándose el índice de masa ventricular izquierda (IMVI). Se realizó análisis estadístico descriptivo, coeficiente de correlación de Pearson para asociación entre variables y análisis multivariado. Resultados: Se incluyeron 33 pacientes, 16 varones, edad 1,2 a 13,4 años. Edad de inicio de DP: 7,3 +/- 5,0 años, tiempo en DP: 13,5 +/- 14,5 meses. El nivel plasmático de 25 (OH) vitD3 fue 34,2 +/- 6,3 pg/ml. Los valores de calcemia y fosfemia fueron 9,8 +/- 0,71 y 5,4 +/- 1,0 mg/dl respectivamente. La PTH fue de 333 +/- 287 pg/ml. El FGF23 en plasma fue de 225,7 +/- 354,3 pg/ml y Klotho 131,6 +/- 72 pg/ml, y en los controles (n = 16) fue de 11,9 +/- 7,2 pg/ ml y 320 +/- 119 pg/ml, respectivamente. La dosis de diálisis (KtV) residual y total fue de 1,6 +/- 1,3 y 2,9 +/- 1.6, respectivamente. El nivel de FGF23 se correlacionó significativamente con la calcemia (p < 0,001, r = 0,85), e inversamente con el KtV residual, sin mostrar relación con la fosfemia. El nivel de Klotho...

Cistatina C, PCR, Log TG/HDLc e Sindrome Metabolica estao Relacionados a Microalbuminuria na Hipertensao / Cystatin C, CRP, log TG/HDLc and metabolic syndrome are associated with microalbuminuria in hypertension

Fundamento: Em pacientes com hipertensão arterial sistêmica, a microalbuminúria é um marcador de lesão endotelial e está associada a um risco aumentado de doença cardiovascular. Objetivo: O objetivo do presente estudo foi determinar os fatores que influenciam a ocorrência de microalbumiúria em pacientes hipertensos com creatinina sérica menor que 1,5 mg/dL. Métodos: Foram incluídos no estudo 133 pacientes brasileiros atendidos em um ambulatório multidisciplinar para hipertensos. Pacientes com creatinina sérica maior do que 1,5 mg/dL e aqueles com diabete mellitus foram excluídos do estudo. A pressão arterial sistólica e diastólica foi aferida. O índice de massa corporal (IMC) e a taxa de filtração glomerular estimada pela fórmula CKD-EPI foram calculados. Em um estudo transversal, creatinina, cistatina C, colesterol total, HDL colesterol, LDL colesterol, triglicerídeos, proteína C-reativa (PCR) e glicose foram mensurados em amostra de sangue. A microalbuminúria foi determinada na urina colhida em 24 horas. Os hipertensos foram classificados pela presença de um ou mais critérios para síndrome metabólica. Resultados: Em análise de regressão múltipla, os níveis séricos de cistatina C, PCR, o índice aterogênico log TG/HDLc e a presença de três ou mais critérios para síndrome metabólica foram positivamente correlacionados com a microalbuminuria (r2: 0,277; p < 0,05). Conclusão: Cistatina C, PCR, log TG/HDLc e presença de três ou mais critérios para síndrome metabólica, independentemente da creatinina sérica, foram associados com a microalbuminúria, um marcador precoce de lesão renal e de risco cardiovascular em pacientes com hipertensão arterial essencial. .

Background: In patients with systemic hypertension, microalbuminuria is a marker of endothelial damage and is associated with an increased risk for cardiovascular disease. Objective: To determine the factors that may lead to the occurrence of microalbuminuria in hypertensive patients with serum creatinine lower than 1.5 mg/dL. Methods: This cross-sectional study included 133 Brazilians with essential hypertension followed up at a hypertension outpatient clinic. Those with serum creatinine higher than 1.5 mg/dL, as well as those with diabetes mellitus, were excluded. Systolic and diastolic blood pressures were measured, and body mass index (BMI) and GFR estimated by using the CKD-EPI formula were calculated. The serum levels of the following were assessed: CysC, creatinine, total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, C-reactive protein (CRP) and fasting glucose. Microalbuminuria was determined in 24-hour urine. Hypertensive patients were classified according to the presence of one or more criteria for metabolic syndrome. Results: In a multiple regression analysis, the serum levels of CysC and CRP, the atherogenic index log TG/HDLc and the presence of three or more criteria for metabolic syndrome were positively correlated with microalbuminuria (r2: 0.277, p < 0.05). Conclusion: CysC, CRP, log TG/HDLc, and the presence of three or more criteria for metabolic syndrome, regardless of serum creatinine, were associated with microalbuminuria, an early marker of kidney damage and cardiovascular risk in patients with essential hypertension. .

Klotho and the Aging Process

The klotho gene was originally identified as a putative age-suppressing gene in mice that extends life span when overexpressed. It induces complex phenotypes resembling human premature aging syndromes when disrupted. The gene was named after a Greek goddess Klotho who spun the thread of life. Since then, various functional aspects of the klotho gene have been investigated, leading to the identification of multiple novel endocrine axes that regulate various metabolic processes and an unexpected link between mineral metabolism and aging. The purposes of this review were to overview recent progress on Klotho research and to discuss a novel aging mechanism.

New Insights into the Roles of Megalin/LRP2 and the Regulation of its Functional Expression

Since the discovery of the low-density lipoprotein receptor (LDLR) and its association with familial hypercholesterolemia in the early 1980s, a family of structurally related proteins has been discovered that has apolipoprotein E as a common ligand, and the broad functions of its members have been described. LRP2, or megalin, is a member of the LDLR family and was initially called gp330. Megalin is an endocytic receptor expressed on the apical surface of several epithelial cells that internalizes a variety of ligands including nutrients, hormones and their carrier proteins, signaling molecules, morphogens, and extracellular matrix proteins. Once internalized, these ligands are directed to the lysosomal degradation pathway or transported by transcytosis from one side of the cell to the opposite membrane. The availability of megalin at the cell surface is controlled by several regulatory mechanisms, including the phosphorylation of its cytoplasmic domain by GSK3, the proteolysis of the extracellular domain at the cell surface (shedding), the subsequent intramembrane proteolysis of the transmembrane domain by the gamma-secretase complex, and exosome secretion. Based on the important roles of its ligands and its tissue expression pattern, megalin has been recognized as an important component of many pathological conditions, including diabetic nephropathy, Lowe syndrome, Dent disease, Alzheimer's disease (AD) and gallstone disease. In addition, the expression of megalin and some of its ligands in the central and peripheral nervous system suggests a role for this receptor in neural regeneration processes. Despite its obvious importance, the regulation of megalin expression is poorly understood. In this review, we describe the functions of megalin and its association with certain pathological conditions as well as the current understanding of the mechanisms that underlie the control of megalin expression.

FGF-23: estado da arte / FGF-23: state of the art

Há aproximadamente 10 anos descobriuse um hormônio denominado FGF-23 (fator de crescimento de fibroblastos 23), um membro da família dos fatores de crescimento de fibroblastos, cujas funções atualmente conhecidas envolvem o metabolismo do fósforo (P) e a inibição da 1α hidroxilase, enzima responsável pela síntese de calcitriol. Tal descoberta possibilitou um novo entendimento sobre os mecanismos de controle do P, um elemento associado com mortalidade, especialmente na doença renal crônica (DRC). Nesta revisão descreveremos diversos aspectos deste hormônio, desde a sua descoberta, função, produção, mecanismo de ação, até os últimos estudos clínicos envolvendo o mesmo. Posteriormente, abordaremos as possíveis repercussões destes estudos na prática clínica.

Approximately 10 years ago, a member of the family of the fibroblast growth factors, the hormone FGF-23 (fibroblast growth factor 23) was discovered. Its currently known functions involve phosphorus (P) metabolism and inhibition of 1αhydroxylase, the enzyme responsible for the synthesis of calcitriol. That discovery led to a better understanding of the mechanisms of P control, an element associated with mortality, especially in chronic kidney disease. This study reviews several aspects of that hormone, such as its discovery, function, production, mechanism of action, and the most recent clinical studies about it. Afterwards, a discussion about the possible effects of those studies on clinical practice will be presented.

Altered kidney morphology and enzymes in streptozotocin induced diabetic rats / Morfología y enzimas renales alteradas en ratas con diabetes inducida por estreptozotocin

We studied the effects of streptozotocin (STZ)-induced diabetes on kidney morphology, anatomy, architecture and on the activities of aminotransferases (AST and ALT), alkaline phosphatase (ALP) and pseudocholinesterase (PChE) in albino rats. The aim of the study was to investigate the association between diabetic kidney complications and kidney enzyme alterations. This study was performed in the Department of Anatomy and Institute of Pharmaceutical Sciences, Baqai Medical University, Karachi and Pathology department of College of Physicians & Surgeons (CPSP) Pakistan in 2007-08. Diabetes was induced by a single dose of STZ (45 mg/kg, b.w.) given intraperitoneally in sodium citrate buffer at pH 4.5. Eighty (80) albino rats were divided into five groups: control (A) and STZ treated (B, C, D, and E) which were sacrificed 2, 4, 6 and 8 weeks post treatment respectively. Histopathology of kidney showed lesions similar to human glomerulosclerosis, glomerular membrane thickening, arteriolar hyalinization and tubular necrosis. Increased levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and pseudocholinesterase (PChE) were observed in the kidney. It seems that the diabetic complications in the kidney are likely to be associated with alterations in enzyme levels.

Se estudiaron los efectos de la diabetes inducida por estreptozotocin (STZ) sobre la morfología, anatomía, arquitectura y sobre las actividades de aminotransferasas (ALT y AST), fosfatasa alcalina (ALP) y pseudocolinesterasa (PChE) en los riñones de ratas albinas. El objetivo del estudio fue investigar la asociación entre las complicaciones renales diabéticas y la alteración de las enzimas renales. Este estudio se realizó en el Departamento de Anatomía y el Instituto de Ciencias Farmacéuticas, Universidad de Medicina Baqai, Karachi y el departamento de Patología de Colegio de Médicos y Cirujanos (CPSP) Pakistán entre el 2007-2008. La diabetes fue inducida por una dosis única de STZ (45 mg / kg de peso corporal) administrada por vía intraperitoneal en tampón de citrato de sodio a pH 4.5. Ochenta (80) ratas albinas fueron divididas en cinco grupos: control (A) y STZ tratados (B, C, D y E), que se sacrificaron a las 2, 4, 6 y 8 semanas después del tratamiento, respectivamente. La histopatología del riñón mostró lesiones similares a la glomeruloesclerosis en humanos, engrosamiento de la membrana glomerular, hialinización arteriolar y necrosis tubular. Aumento de los niveles de aspartato aminotransferasa (AST), alanina aminotransferasa (ALT), fosfatasa alcalina (ALP) y pseudocolinesterasa (PChE) fueron observados en el riñón. Parece que las complicaciones de la diabetes en el riñón están directamente asociadas con alteraciones en los niveles de las enzimas.

Hepato and reno protective action of Calendula officinalis L. flower extract.

Flower extract of C. officinalis L. was evaluated for its protective effect against CCl4 induced acute hepatotoxicity and cisplatin induced nephrotoxicity. The activities of serum marker enzymes of liver injury like glutamate pyruvate transaminase (SGPT), glutamate oxaloacetate transaminase (SGOT) and alkaline phosphatase (ALP) which were increased by CCl4 injection was found to be significantly reduced by the pretreatment of the flower extract at 100 and 250 mg/kg body weight. The lipid peroxidation in liver, the marker of membrane damage and the total bilirubin content in serum were also found to be at significantly low level in the extract pretreated group, indicating its protective role. The kidney function markers like urea and creatinine were significantly increased in cisplatin treated animals. However, their levels were found to be lowered in the extract pretreated groups (100 and 250 mg/kg body weight). Moreover, cisplatin induced myelosuppression was ameliorated by the extract pretreatment. Treatment with the extract produced enhancement of antioxidant enzymes--superoxide dismutase and catalase and glutathione. Results suggest a protective role of the flower extract of C. officinalis against CCl4 induced acute hepatotoxicity and cisplatin induced nephrotoxicity. Extract has been found to contain several carotenoids of which lutein, zeaxanthin and lycopene predominates. Possible mechanism of action of the flower extract may be due to its antioxidant activity and reduction of oxygen radicals.

The role of stress-activated protein kinase signaling in renal pathophysiology

Two major stress-activated protein kinases are the p38 mitogen-activated protein kinase (MAPK) and the c-Jun amino terminal kinase (JNK). p38 and JNK are widely expressed in different cell types in various tissues and can be activated by a diverse range of stimuli. Signaling through p38 and JNK is critical for embryonic development. In adult kidney, p38 and JNK signaling is evident in a restricted pattern suggesting a normal physiological role. Marked activation of both p38 and JNK pathways occurs in human renal disease, including glomerulonephritis, diabetic nephropathy and acute renal failure. Administration of small molecule inhibitors of p38 and JNK has been shown to provide protection from renal injury in different types of experimental kidney disease through inhibition of renal inflammation, fibrosis, and apoptosis. In particular, a role for JNK signaling has been identified in macrophage activation resulting in up-regulation of pro-inflammatory mediators and the induction of renal injury. The ability to provide renal protection by blocking either p38 or JNK indicates a lack of redundancy for these two signaling pathways despite their activation by common stimuli. Therefore, the stress-activated protein kinases, p38 and JNK, are promising candidates for therapeutic intervention in human renal diseases.

The effects of pentoxifylline into the kidneys of rats in a model of unilateral hindlimb ischemia/reperfusion injury

PURPOSE: To study the role of pentoxifylline (PTX) on remote kidney injury caused by muscle ischemia of left hindlimb of rats. METHODS: After xylazine and ketamine anesthesia, the left hindlimb of rats (n=66) were submitted to 6 hours ischemia (clamping the left common iliac artery). Three groups were used: sham group (SG, n=6), early group (EG, n=30) with reperfusion after 4 hours and late group (LG, n=30) with reperfusion after 24 hours. The saline solution (EG1, n=10 and LG1, n=10) or PTX (40mg.Kg-1) was administered in the reperfusion beginning (EG2, n=10/LG2, n=10) or divided in two doses in the ischemia beginning and reperfusion beginning (EG3, n=10/LG3, n=10). The plasmatic creatinokinase, urea, creatinine, sodium and potassium values were measure and histological samples from left kidney were prepared and H&E stained for scored cellular necrosis and degeneration of kidney tubules and thickness glomerulus determination. The apoptosis index was determined by immunohistochemical expression of the caspase-3. The tests of Mann-Whitney and Kruskal-Wallis (p < 0.05) were applied. RESULTS: The urea (90.5 ± 30.96 mg.dL-1), creatinine (2.28 ± 0.54 mg.dL-1), potassium (16 ± 3.66 mmol.dL-1) and mesangium thickness (0.97 ± 0.42 µm) values were significantly higher in group LG3. There was no significantly difference of caspase 3 expression between EG2 (16.35 ± 1.65 percent) and LG3 (15.57 ± 2.54 percent), and both were significantly worse than SG (9.8 ± 1.98 percent). CONCLUSIONS: The PTX has some protecting effect on remote kidney injury due to hindlimb ischemia/reperfusion injury only in the early phase of reperfusion.

OBJETIVO: Estudar o papel da pentoxifilina (PTX) nas lesões à distância no rim causadas pela isquemia no membro posterior esquerdo de ratos. MÉTODOS: Sob anestesia com xilazina e quetamina, o membro posterior de ratos (n=66) foi submetido a 6 horas de isquemia pelo clampeamento da artéria ilíaca comum esquerda. Foram estudados três grupos: grupo simulado (SG, n=6), grupo precoce (EG, n=30) após quatro horas de reperfusão e grupo tardio (LG, n=30) após 24 de reperfusão. A solução salina (EG1, n=10 e LG1, n=10) ou a PTX (40mg.Kg-1) foram administradas no início da reperfusão(EG2, n=10/LG2, n=10) ou divididas em duas aplicações no início da isquemia e no início da reperfusão (EG3, n=10/LG3, n=10). Foram medidos os valores plasmáticos da creatinofosfoquinase, uréia, creatinina, sódio e potássio. Amostras do rim esquerdo foram preparadas e coradas em HE para realizar o escore de necrose de células tubulares renais ou presença de obstrução tubular renal na área do córtex renal e da presença do espessamento do mesângio glomerular. O índice de apoptose foi determinado pela expressão imunoistoquímica da caspase-3. Foram aplicados os testes de Mann-Whitney e Kruskal-Wallis (p < 0.05). RESULTADOS: a dosagem de uréia (90,5 ± 30,96 mg.dL-1), creatinina (2,28 ± 0,54 mg.dL-1), potássio (16 ± 3,66 mmol.dL-1) e a espessura do mesângio(0,97 ± 0,42 µm) foram significantemente maiores nos animais do grupo LG3. Não houve diferença significante na expressão da caspase-3 entre os grupos EG2 (16,35 ± 1,65 por cento) e LG3 (15,57 ± 2,54 por cento) e ambos foram significantemente piores que o grupo SG (9,8 ± 1,98 por cento). CONCLUSÃO: A PTX oferece algum efeito protetor nas lesões à distância nos rins de animais submetidos à lesão de isquemia e reperfusão de membro posterior, no período de até quatro horas após a reperfusão.

Aplicações da biologia molecular à patologia renal: revisão da literatura / Application of molecular biology to renal pathology: review of the literature

As doenças renais são importante causa de morbidade e mortalidade. Suas características clínicas e morfológicas e seu potencial de progressão são bastante heterogêneos. O diagnóstico anatomopatológico das doenças renais não se fundamenta unicamente nas suas características histopatológicas, e o advento da Biologia Molecular oferece novas abordagens ao diagnóstico das doenças renais. Entre as aplicações mais promissoras, estão a análise degenes e seus polimorfismos, o estudo do transcriptoma, com a identificação dos padrões de expressão de RNA, e a investigação do proteoma. A introdução de métodos moleculares em associação aos parâmetros clínicos e morfológicos já estabelecidos deverá proporcionar melhor compreensão dos mecanismos fisiopatológicos, maior acurácia diagnóstica e abordagens terapêuticas precisas, adequadas e personalizadas.

Renal diseases are an important cause of morbidity and mortality. Clinical and morphological features and progression potential of these diseases are heterogeneous. Their diagnosis is frequently not based solely on histopathological characteristics and the introduction of novel molecular biology techniques offers new diagnostic approaches. The most promising applications are the analysis of genes and polymorphisms, the study of mRNA transcripts, the identification of patterns of gene expression, and proteomic analysis. The introduction of molecular biology techniques in association with long established clinical and morphological parameters may enhance our understanding of the physiopathologic mechanisms, improve the diagnostic accuracy, and allow adequate, precise and tailored therapeutic approaches.

Sodium transporters in kidney role in health and disease.

Sodium is an important cation and has an important role in BP regulation and ECF balance. Kidney plays an important role in sodium balance. Almost 99% of filtered sodium is reabsorbed. The absorption occurs via sodium transporters located in the various segments of the nephron. Each of these transporters has unique features and is blocked by a specific diuretic. The activating and inactivating mutations of these transporters are associated with important clinical syndromes. The understanding of these transporters and their mutations is essential for proper diagnosis and management of syndromes associated with the defects of these transporters. Also the knowledge of sodium transporters helps in understanding the role of kidney in pathogenesis of hypertension and pharmacodynamics of diuretic action.

Role of VEGF in Kidney Development, Microvascular Maintenance and Pathophysiology of Renal Disease

Vascular endothelial growth factor, VEGF, is essential for endothelial cell differentiation (vasculogenesis) and for the sprouting of new capillaries from preexisting vessels (angiogenesis). In addition, there is strong evidence that VEGF is a survival factor allowing the cells to survive and proliferate under conditions of extreme stress. Hypoxia is a key regulator of VEGF gene expression. Besides hypoxia, many cytokines, hormones and growth factors can up-regulate VEGF mRNA expression in various cell types. VEGF is present in the glomerulus of both the fetal and adult kidney. The VEGF produced by glomerular epithelial cell may be responsible for maintenance of the fenestrated phenotype of glomerular epithelial cells, thus facilitating the high rate of glomerular ultrafiltration. But there is little known about the role of VEGF in the tubule. VEGF is thought to be involved in many kinds of kidney diseases. Whereas VEGF has a beneficial role in the pathogenesis in some diseases, it does harmful action in others. Because VEGF is known to be associated with the pathogenesis of some diseases, such as diabetic nephropathy, renal tumor and polycystic kidney disease, the study about the role of VEGF is going to be a target for disease control. On the other hand, an attempt at enhancing the role of VEGF has to be made at diseases like several ARF models and experimental glomerulonephritis.

Effects of microcystin-LR in isolated perfused rat kidney

Microcystin is a hepatotoxic peptide which inhibits protein phosphatase types 1 and 2A. The objective of the present study was to evaluate the physiopathologic effects of microcystin-LR in isolated perfused rat kidney. Adult Wistar rats (N = 5) of both sexes (240-280 g) were utilized. Microcystin-LR (1 µg/ml) was perfused over a period of 120 min, during which samples of urine and perfusate were collected at 10-min intervals to determine the levels of inulin, sodium, potassium and osmolality. We observed a significant increase in urinary flow with a peak effect at 90 min (control (C) = 0.20 + or- 0.01 and treated (T) = 0.32 + or - 0.01 ml g-1 min(-1), P<0.05). At 90 min there was a significant increase in perfusate pressure (C = 129.7 + or - 4.81 and T = 175.0 + or - 1.15 mmHg) and glomerular filtration rate (C = 0.66 + or - 0.07 and T = 1.10 + or - 0.04 ml g-1 min(-1) and there was a significant reduction in fractional sodium tubular transport at 120 min (C = 78.6 + or - 0.98 and T = 73.9 + or - 0.95 percent). Histopathologic analysis of the perfused kidneys showed protein material in the urinary space, suggestive of renal toxicity. These data demonstrate renal vascular, glomerular and urinary effects of microcystin-LR, indicating that microcystin acts directly on the kidney by probable inhibition of protein phosphatases

Alteraciones metabólicas en 2612 pacientes con litiasis renal / Metabolic changes in 2612 patients with nephrolithiasis

La litiasis renal constituye por su frecuencia la 3ra alteración de las vías urinarias. La prevalencia en la Ciudad de Buenos Aires es del 4 por ciento, según estudios recientes. Se presentan los resultados metabólicos de 2612 pacientes estudiados con un mismo protocolo ambulatorio para estudio bioquímico de litiasis renal. Se encontraron alteraciones en 2423 pacientes (92.8 por ciento). El 61.5 por ciento como única alteración y 31.2 por ciento en forma asociada. No pudimos obtener diagnóstico en 189 pacientes (7.2 por ciento). Los diagnósticos más frecuentes como única alteración fueron la hipercalciuria idiopática en el 31.2 por ciento, la hiperuricosuria y diátesis gotosa en el 9.4 y 5.4 por ciento respectivamente. Otros diagnósticos fueron hipomagnesuria (6.7 por ciento), hiperparatiroidismo primario (2.6 por ciento), hiperoxaluria (1.3 por ciento) y cistinuria (0.45 por ciento). La hipercalciuria asociada a otros diagnósticos se observó en el 58.1 por ciento y los trastornos del ácido úrico en el 36.8 por ciento. Además de los trastornos metabólicos descriptos observamos un 12 por ciento de pacientes com bajo volumen urinario. Estos datos están en concordancia con la mayoría de las series publicadas y resaltan la importancia de encontrar un diagnóstico bioquímico en estos pacientes que permita el tratamiento específico que evite la recurrencia.