Vitamin D deficiency contributes to the diabetic kidney disease progression via increase ZEB1/ZEB2 expressions.

BACKGROUND: Diabetic kidney disease (DKD) remains one of the main causes of end-stage renal disease (ESRD) and mortality in diabetic patients worldwide. Vitamin D deficiency (VitDD) is one of the main consequences of different chronic kidney disease (CKD) types and is associated with rapid progression to ESRD. Nevertheless, the mechanisms that lead to this process are poorly understood. This study aimed to characterize a model of diabetic nephropathy progression in VitDD and the epithelial-mesenchymal-transition (EMT) role in these processes. METHODS: Wistar Hannover rats received a diet with or without VitD before type 1 diabetes (T1D) induction. After this procedure, the rats were accompanied for 12 and 24 weeks after T1D induction and the renal function, structure, cell transdifferentiating markers and zinc finger e-box binding homeobox 1/2 (ZEB1/ZEB2) contribution to kidney damage were evaluated during the DKD progression. RESULTS: The results showed an increase in glomerular tuft, mesangial and interstitial relative areas and renal function impairment in VitD-deficient diabetic rats compared to diabetic rats that received a VitD-containing diet. These alterations can be associated with increased expression of EMT markers, ZEB1 gene expression, ZEB2 protein expression and TGF-ß1 urinary excretion. Decreased miR-200b expression, an important post-transcriptional regulator of ZEB1 and ZEB2 was also observed. CONCLUSION: Our data demonstrated that VitD deficiency contributes to the rapid development and progression of DKD in diabetic rats induced by increase ZEB1/ZEB2 expressions and miR-200b downregulation.

Obesity-like metabolic effects of high-carbohydrate or high-fat diets consumption in metabolic and renal functions.

Present study investigated which diet, high-carbohydrate (HCD) or high-fat (HFD), most effectively induces classical characteristics of obesity in mice. Mice were fed commercial chow (control), an HCD, or an HFD for 12 weeks. HFD and HCD increased body weight, fat mass, and glycaemia, whereas the HFD augmented insulinemia. In the kidney, the HFD caused albuminuria, and reductions in fractional Na+ excretion, Thromboxane B2 (TXB2) excretion, and urinary flow, whereas the HCD reduced glomerular filtration, plasma osmolality, and TXB2 and Prostaglandin E2 excretion. The consumption of HFD and HCD modified parameters that indicate histopathological changes, such as proliferation (proliferating-cell-nuclear antigen), inflammation (c-Jun N-terminal-protein), and epithelial-mesenchymal transition (vimentin, and desmin) in renal tissue, but the HCD group presents fewer signals of glomerular hypertrophy or tubule degeneration. In summary, the HCD generated the metabolic and renal changes required for an obesity model, but with a delay in the development of these modifications concerning the HFD.

Paricalcitol Improves the Angiopoietin/Tie-2 and VEGF/VEGFR2 Signaling Pathways in Adriamycin-Induced Nephropathy.

Renal endothelial cell (EC) injury and microvascular dysfunction contribute to chronic kidney disease (CKD). In recent years, increasing evidence has suggested that EC undergoes an endothelial-to-mesenchymal transition (EndoMT), which might promote fibrosis. Adriamycin (ADR) induces glomerular endothelial dysfunction, which leads to progressive proteinuria in rodents. The activation of the vitamin D receptor (VDR) plays a crucial role in endothelial function modulation, cell differentiation, and suppression of the expression of fibrotic markers by regulating the production of nitric oxide (NO) by activating the endothelial NO synthase (eNOS) in the kidneys. This study aimed to evaluate the effect of paricalcitol treatment on renal endothelial toxicity in a model of CKD induced by ADR in rats and explore mechanisms involved in EC maintenance by eNOS/NO, angiopoietins (Angs)/endothelium cell-specific receptor tyrosine kinase (Tie-2, also known as TEK) and vascular endothelial growth factor (VEGF)-VEGF receptor 2 (VEGFR2) axis. The results show that paricalcitol attenuated the renal damage ADR-induced with antiproteinuric effects, glomerular and tubular structure, and function protection. Furthermore, activation of the VDR promoted the maintenance of the function and structure of glomerular, cortical, and external medullary endothelial cells by regulating NO production. In addition, it suppressed the expression of the mesenchymal markers in renal tissue through attenuation of (transforming growth factor-beta) TGF-ß1/Smad2/3-dependent and downregulated of Ang-2/Tie-2 axis. It regulated the VEGF/VEGFR2 pathway, which was ADR-deregulated. These effects were associated with lower AT1 expression and VDR recovery to renal tissue after paricalcitol treatment. Our results showed a protective role of paricalcitol in the renal microvasculature that could be used as a target for treating the beginning of CKD.

Alterations in Kidney Structures Caused by Age Vary According to Sex and Dehydration Condition.

Aging is a complex biological process, resulting in gradual and progressive decline in structure and function in many organ systems. Our objective is to determine if structural changes produced by aging vary with sex in a stressful situation such as dehydration. The expression of Slc12a3 mRNA in the renal cortex, α-smooth muscle actin (α-SMA), and fibronectin was evaluated in male and female rats, aged 3 and 18 months, submitted and not submitted to water deprivation (WD) for 48 h, respectively. When comparing ages, 18-month-old males showed a lower expression of Slc12a3 mRNA than 3-month-old males, and control and WD 18-month-old male and female rats exhibited a higher expression of α-SMA than the respective 3-month-old rats. Fibronectin was higher in both control and WD 18-month-old males than the respective 3-month-old males. In females, only the control 18-month-old rats showed higher fibronectin than the control 3-month-old rats. When we compared sex, control and WD 3-month-old female rats had a lower expression of Slc12a3 mRNA than the respective males. The WD 18-month-old male rats presented a higher expression of fibronectin and α-SMA than the WD 18-month-old female rats. When we compared hydric conditions, the WD 18-month-old males displayed a lower relative expression of Slc12a3 mRNA and higher α-SMA expression than the control 18-month-old males. Aging, sex, and dehydration lead to alterations in kidney structure.

Ovariectomy exacerbates glycerol-induced acute kidney injury in rats / A ovariectomia intensifica a lesão renal aguda induzida pelo glicerol em ratas

Objective: This study aimed to evaluate the effects of ovariectomy on glycerol-induced renal changes in rats. Methods: Twenty-four female Wistar rats were submitted to ovariectomized (OVX) or sham surgery. One week after surgery, the animals received an intramuscular injection (8ml/kg) of 50% glycerol or saline (0.15 M) solution. These animals were divided into the following groups (n=6 per group): Sham, sham-operated female rats injected with saline; OVX, ovariectomized female rats injected with saline; Sham+Gly, sham-operated female rats injected with glycerol; OVX+Gly, ovariectomized female rats injected with glycerol. All rats were euthanized 3 days after the injections and the kidneys were removed for histological and immunohistochemical studies. Blood and urine samples were also collected for renal function studies. Results: The OVX+Gly group presented higher creatinine serum levels, as well as greater fractional excretion of sodium and urinary flow than the Sham+Gly group. Histological lesions and tubulointerstitial staining for macrophages, nuclear factor-kappa B, and nitrotyrosine were more pronounced in the renal cortex of the OVX+Gly group compared to the Sham+Gly group. Conclusion: We conclude that ovariectomy aggravated changes in renal function and structure in glycerol-induced acute kidney injury by the intensification of the proinflammatory tissue response.

Objetivo: Avaliar os efeitos da ovariectomia nas alterações renais induzidas pelo glicerol em ratas. Métodos: Vinte e quatro ratas Wistar foram submetidas à ovariectomia (OVX) ou cirurgia sham (intervenção falsa). Uma semana após a cirurgia, os animais receberam injeção intramuscular (8ml/kg) de glicerol a 50% ou solução salina (0,15 M). As ratas foram divididas nos seguintes grupos (n=6 por grupo): Sham, fêmeas sham-operadas e injetadas com solução salina; OVX, fêmeas ovariectomizadas e injetadas com solução salina; Sham+Gly, fêmeas sham-operadas e injetados com glicerol; OVX+Gly, fêmeas ovariectomizadas e injetadas com glicerol. Todas as ratas foram eutanasiadas 3 dias após as injeções e os rins foram removidos para estudos histológicos e imuno-histoquímicos. Amostras de sangue e urina também foram coletadas para estudos de função renal. Resultados: O grupo OVX+Gly apresentou maiores níveis séricos de creatinina, assim como maiores fração de excreção de sódio e fluxo urinário do que o grupo Sham+Gly. As lesões histológicas e imunomarcação tubulointersticial para macrófagos, fator nuclear-kappa B e nitrotirosina foram mais pronunciadas no córtex renal do grupo OVX+Gly em comparação ao grupo Sham+Gly. Conclusão: Concluímos que a ovariectomia agravou as alterações na função e estrutura renal, na lesão renal aguda induzida por glicerol, pela intensificação da resposta tecidual pró-inflamatória.

Neonatal hyperoxia: effects on nephrogenesis and the key role of klotho as an antioxidant factor.

A congenital or programmed reduction in glomerular number increases the susceptibility to hypertension and kidney injury in adulthood thus, premature birth or low birth weight, leading to a low glomerular endowment, can be associated with these two diseases. Renal morphogenesis is sensitive to hypoxia which is a physiological trigger for the expression of vascular endothelial growth factor. On the other hand, hyperoxia increases oxidative stress and adversely affects glomerular and tubular development, and is associated with a substantial reduction of renal klotho expression in adulthood. Preterm newborns are often submitted to oxygen therapy, exposing them to an acute high-oxygen level situation, in contrast to the intrauterine low-oxygen environment. Investigating the role of klotho on kidney development leads to the understanding of the possible mechanisms related to disorders in the preterm neonatal kidney exposed to hyperoxia and its long term effects in adulthood.

Acute kidney injury induced by glycerol is worsened by orchiectomy and attenuated by testosterone replacement.

Although several studies have demonstrated that the male gender represents an independent risk factor for renal disease, evidence shows that androgens exert renal protective actions. The findings are controversial and no studies have evaluated the effects of orchiectomy and testosterone replacement on glycerol-induced renal injury. Male Wistar rats were submitted to orchiectomy or sham surgery and divided into four groups: SC, sham control rats injected with NaCl; SG, sham rats injected with glycerol; OG, orchiectomized rats injected with glycerol; OGT, orchiectomized rats injected with glycerol and testosterone. Testosterone was administered daily for 14 days in the OGT group. After 11 days of testosterone replacement in the OGT group, SC rats were submitted to a saline injection, while SG, OG and OGT rats received glycerol. All rats were euthanized three days after injections. OG rats presented higher serum creatinine and urea, and sodium excretion, compared to SC and SG, while testosterone attenuated these changes. Acute tubular necrosis was also mitigated by testosterone. Renal immunostaining for macrophages, lymphocytes and NF-κB was higher in OG compared to SC and SG. In addition, renal interleukin-1ß, Caspase 3 and AT1 gene expression was higher in OG rats compared to SG. Testosterone attenuated these alterations, except the NF-κB immunostaining. The renal NO was lower in OG rats compared to SG. Only the OG rats presented decreases in serum NO and renal HO-1, and increased TNF-α, angiotensinogen and AT1 expression compared to SC. We conclude that orchiectomy worsened glycerol-induced kidney injury, while testosterone attenuated this renal damage.

Effects of endogenous H2S production inhibition on the homeostatic responses induced by acute high-salt diet consumption.

The gaseous modulator hydrogen sulfide (H2S) is synthesized, among other routes, by the action of cystathionine-γ-lyase (CSE) and importantly participates in body fluid homeostasis. Therefore, the present study aimed to evaluate the participation of H2S in behavioral, renal and neuroendocrine homeostatic responses triggered by the acute consumption of a high Na+ diet. After habituation, adult male Wistar rats were randomly distributed and maintained for seven days on a control [CD (0.27% of Na+)] or hypersodic diet [HD (0.81% of Na+)]. CD and HD-fed animals were treated with DL-Propargylglycine (PAG, 25 mg/kg/day, ip) or vehicle (0.9% NaCl in equivalent volume) for the same period. At the end of the experiment, animals were euthanized for blood and tissue collection. We demonstrated that a short-term increase in dietary Na+ intake, in values that mimic the variations in human consumption (two times the recommended) significantly modified hydroelectrolytic homeostasis, with repercussions in the hypothalamic-neurohypophysial system and hypothalamic-pituitary-adrenal axis function. These findings were accompanied by the development of a clear inflammatory response in renal tubular cells and microvascular components. On the other hand, the inhibition of the endogenous production of H2S by CSE provided by PAG treatment prevented the inflammation induced by HD. In the kidney, PAG treatment induced the overexpression of inducible nitric oxide synthase in animals fed with HD. Taken together, these data suggest, therefore, that HD-induced H2S production plays an important proinflammatory role in the kidney, apparently counter regulating nitric oxide actions in renal tissue.

When Less or More Isn't Enough: Renal Maldevelopment Arising From Disequilibrium in the Renin-Angiotensin System.

Environmental and nutritional factors during fetal and neonatal life can have long-lasting effects on renal functions and physiology and susceptibility to kidney disease in adulthood. All components of the renin-angiotensin system (RAS) are highly expressed in the kidneys during the period of renal development. The RAS plays a central role in the regulation of various cellular growth factors and stimulates adhesion molecules and cellular migration. The use of antagonists of this system during fetal development represents a major risk factor for hypertension, renal vascular dysfunction, and kidney medulla atrophy in adulthood. The inappropriate activation of the RAS by vitamin D (VitD) deficiency has been studied in recent years. Clinical and experimental studies have demonstrated an inverse relationship between circulating VitD levels and blood pressure, plasma and renin activity, and an increase in angiotensin II and the receptor AT1. These data raise new questions about the importance of the integrity of the RAS during development since RAS pathway inhibitors and VitD deficiency have opposing functions. This is a literature review on the possible mechanisms by which antagonists of the RAS and VitD deficiency during fetal development provoke disturbances in kidney structure and function. Potential mechanisms are presented and discussed, and the possible pathways by which an imbalanced maternal RAS may negatively impact fetal development and have consequences in adulthood are also explored.

Protective effect of calcitriol on rhabdomyolysis-induced acute kidney injury in rats.

Glycerol injection in rats can lead to rhabdomyolysis, with the release of the intracellular muscle content to the extracellular compartment and acute kidney injury (AKI). Oxidative stress and the inflammatory processes contribute to the disturbances in renal function and structure observed in this model. This study evaluated the effect of calcitriol administration in AKI induced by rhabdomyolysis and its relationship with oxidative damage and inflammatory process. Male Wistar Hannover rats were treated with calcitriol (6 ng/day) or vehicle (0.9% NaCl) for 7 days and were injected with 50% glycerol or saline 3 days after the beginning of calcitriol or saline administration. Four days after glycerol or saline injection, urine, plasma and renal tissue samples were collected for renal function and structural analysis. The oxidative stress and the inflammatory processes were also evaluated. Glycerol-injected rats presented increased sodium fractional excretion and decreased glomerular filtration rates. These alterations were associated with tubular injury in the renal cortex. These animals also presented increased oxidative damage, apoptosis, inflammation, higher urinary excretion of vitamin D-binding protein and decreased cubilin expression in renal tissue. All these alterations were less intense in calcitriol-treated animals. This effect was associated with decreases in oxidative damage and inflammation.

Previous Exercise Training Reduces Markers of Renal Oxidative Stress and Inflammation in Streptozotocin-Induced Diabetic Female Rats.

The aim of this study is to evaluate the effects of regular moderate exercise training initiated previously or after induction of diabetes mellitus on renal oxidative stress and inflammation in STZ-induced diabetic female rats. For this purpose, Wistar rats were divided into five groups: sedentary control (SC), trained control (TC), sedentary diabetic (SD), trained diabetic (TD), and previously trained diabetic (PTD). Only the PTD group was submitted to treadmill running for 4 weeks previously to DM induction with streptozotocin (40 mg/kg, i.v). After confirming diabetes, the PTD, TD, and TC groups were submitted to eight weeks of exercise training. At the end of the training protocol, we evaluated the following: glycosuria, body weight gain, plasma, renal and urinary levels of nitric oxide and thiobarbituric acid reactive substances, renal glutathione, and immunolocalization of lymphocytes, macrophages, and nuclear factor-kappa B (NF-κB/p65) in the renal cortex. The results showed that exercise training reduced glycosuria, renal TBARS levels, and the number of immune cells in the renal tissue of the TD and PTD groups. Of note, only previous exercise increased weight gain and urinary/renal NO levels and reduced NF-κB (p65) immunostaining in the renal cortex of the PTD group. In conclusion, our study shows that exercise training, especially when initiated previously to diabetes induction, promotes protective effects in diabetic kidney by reduction of renal oxidative stress and inflammation markers in female Wistar rats.

Calcitriol reduces kidney development disorders in rats provoked by losartan administration during lactation.

Calcitriol has important effects on cellular differentiation and proliferation, as well as on the regulation of the renin gene. Disturbances in renal development can be observed in rats exposed to angiotensin II (AngII) antagonists during lactation period. The lack of tubular differentiation in losartan-treated rats can affect calcitriol uptake. This study evaluated the effect of calcitriol administration in renal development disturbances in rats provoked by losartan (AngII type 1 receptor antagonist) administration during lactation. Animals exposed to losartan presented higher albuminuria, systolic blood pressure, increased sodium and potassium fractional excretion, and decreased glomerular filtration rate compared to controls. These animals also showed a decreased glomerular area and a higher interstitial relative area from the renal cortex, with increased expression of fibronectin, alpha-SM-actin, vimentin, and p-JNK; and an increased number of macrophages, p-p38, PCNA and decreased cubilin expression. Increased urinary excretion of MCP-1 and TGF-ß was also observed. All these alterations were less intense in the losartan + calcitriol group.The animals treated with calcitriol showed an improvement in cellular differentiation, and in renal function and structure. This effect was associated with reduction of cell proliferation and inflammation.

The role of oxidative stress in renal injury induced in rats by losartan exposure during lactation.

INTRODUCTION: Rats exposed to angiotensin II (AII) receptor antagonists during lactation present progressive disturbances in renal development that lead to progressive alterations in renal function and structure. This study evaluates the role of oxidative stress in the renal changes induced by exposure to losartan, a type 1 AII receptor antagonist, in rats during lactation. MATERIALS AND METHODS: Male Wistar pups were divided into: Control, pups of dams that received 2% sucrose solution; Control-tempol, pups of dams that received tempol (0.34 g/l), a superoxide dismutase mimetic compound; Losartan, pups of dams that received losartan (100 mg/kg/day), and Losartan-tempol, pups of dams that received losartan and tempol. Losartan and/or tempol were administered during lactation. Blood and urine samples were collected at 21 or 60 days, and the kidneys were removed. RESULTS: Losartan-treated pups exhibited disturbances in renal function and structure that persisted into adulthood. Tempol treatment reduced oxidative stress and attenuated the changes induced by losartan in the glomerular filtration rate, desmin expression at the glomerular edge, vimentin in tubular cells, as well as apoptosis and inflammatory infiltration in the renal cortex. CONCLUSION: Oxidative stress contributes at least in part to the renal injury observed in pups exposed to losartan during lactation.

Renal macrophage infiltration is associated with a poor outcome in IgA nephropathy.

OBJECTIVES: The objectives of our study were as follows: 1) to analyze the prognostic value of macrophage infiltration in primary IgA nephropathy (IgAN) and 2) to study the relationship between macrophages and other factors associated with the development of renal fibrosis, including mast cells, TGF-ß1, α-SMA and NF-kB. METHODS: We analyzed 62 patients who had been diagnosed with IgAN between 1987 and 2003. Immunohistochemical staining was performed with monoclonal antibodies against CD68 and mast cell tryptase and polyclonal antibodies against TGF-ß1, α-SMA and NF-kB p65. We also used Southwestern histochemistry for the in situ detection of activated NF-kB. RESULTS: The infiltration of macrophages into the tubulointerstitial compartment correlated with unfavorable clinical and histological parameters, and a worse clinical course of IgAN was significantly associated with the number of tubulointerstitial macrophages. Kaplan-Meier curves demonstrated that increased macrophage infiltration was associated with decreased renal survival. Moreover, the presence of macrophages was associated with mast cells, tubulointerstitial α-SMA expression and NF-kB activation (IH and Southwestern histochemistry). In the multivariate analysis, the two parameters that correlated with macrophage infiltration, proteinuria and tubulointerstitial injury, were independently associated with an unfavorable clinical course. CONCLUSION: An increased number of macrophages in the tubulointerstitial area may serve as a predictive factor for poor prognosis in patients with IgAN, and these cells were also associated with the expression of pro-fibrotic factors.

Renal macrophage infiltration is associated with a poor outcome in IgA nephropathy

OBJECTIVES: The objectives of our study were as follows: 1) to analyze the prognostic value of macrophage infiltration in primary IgA nephropathy (IgAN) and 2) to study the relationship between macrophages and other factors associated with the development of renal fibrosis, including mast cells, TGF-β1, α-SMA and NF-kB. METHODS: We analyzed 62 patients who had been diagnosed with IgAN between 1987 and 2003. Immunohistochemical staining was performed with monoclonal antibodies against CD68 and mast cell tryptase and polyclonal antibodies against TGF-β1, α-SMA and NF-kB p65. We also used Southwestern histochemistry for the in situ detection of activated NF-kB. RESULTS: The infiltration of macrophages into the tubulointerstitial compartment correlated with unfavorable clinical and histological parameters, and a worse clinical course of IgAN was significantly associated with the number of tubulointerstitial macrophages. Kaplan-Meier curves demonstrated that increased macrophage infiltration was associated with decreased renal survival. Moreover, the presence of macrophages was associated with mast cells, tubulointerstitial α-SMA expression and NF-kB activation (IH and Southwestern histochemistry). In the multivariate analysis, the two parameters that correlated with macrophage infiltration, proteinuria and tubulointerstitial injury, were independently associated with an unfavorable clinical course. CONCLUSION: An increased number of macrophages in the tubulointerstitial area may serve as a predictive factor for poor prognosis in patients with IgAN, and these cells were also associated with the expression of pro-fibrotic factors.

Postnatal renal abnormalities in rats exposed to losartan during lactation.

BACKGROUND/AIMS: Rats exposed to losartan during lactation exhibit progressive changes in renal function and structure. This study analyzed the early events in pups from dams that received losartan during lactation. METHODS: Male Wistar rats from dams that received 2% sucrose (control, n = 25) or losartan (100 mg/kg/day) diluted in 2% sucrose (n = 33) during lactation were anesthetized 21 days after birth. Blood and urine samples were collected to assess renal function, and kidneys were removed for histological, immunohistochemical, Western blot, lipid peroxidation and glutathione analyses. RESULTS: The group exposed to losartan exhibited increased albuminuria and fractional sodium and potassium excretion, decreased glomerular area and interstitial expansion. Immunohistochemical analyses demonstrated increased tubulointerstitial macrophage infiltration, apoptosis and increased vimentin and α-smooth-muscle-actin expression in animals exposed to losartan. In addition, the glomeruli of animals exposed to losartan exhibited increased peripheral desmin expression and reduced glomerular epithelial protein 1 and podocin expression compared to controls. Lastly, renal lipid peroxidation and glutathione levels were higher in the losartan-treated pups. CONCLUSION: Pups exposed to losartan during lactation exhibited adverse changes in renal function and structure, and tubulointerstitial inflammation at 21 days of age that were associated with apoptosis and oxidative stress.

Role of endogenous hydrogen sulfide on renal damage induced by adriamycin injection.

A single injection of adriamycin (ADR) induces marked and persistent proteinuria in rats that progress to glomerular and tubulointerstitial lesions. It has been shown that ADR-induced nephrotoxicity is mediated, at least in part, by oxidative stress that lead to inflammation. Endogenous hydrogen sulfide (H2S) is synthesized from L-cysteine and is an important signaling molecule in inflammation. This study evaluates the effect of DL-propargylglycine (PAG), an inhibitor of endogenous H2S formation, on the evolution of renal damage induced by ADR. The rats were injected i.p. with 0.15 M NaCl or PAG (50 mg/kg) 2 h after ADR injection (3.5 mg/kg). Control rats were injected with 0.15 M NaCl or PAG only. Twenty hours urine samples were collected for albuminuria and creatinine measurements on days 1 and 14 after saline or ADR injections and on days 2 and 15 blood samples were collected to measure plasma creatinine, then the rats were killed. The kidneys were removed for H2S formation evaluation, renal lipid peroxidation and glutathione levels, and histological and immunohistochemical analysis. On day 2 after ADR injection the rats presented increase in oxidative stress associated with neutrophils and macrophages influx in renal tissue. On day 15 the rats also presented increased desmin expression at glomerular edge and vimentin in cortical tubulointerstitium, as well as albuminuria. All these alterations were reduced by PAG injection. The protective effect of PAG on ADR nephrotoxicity was associated to decreased H2S formation and to restriction of oxidative stress and inflammation in the renal cortex.

Inhibition of hydrogen sulphide formation reduces cisplatin-induced renal damage.

BACKGROUND: Cisplatin (CP)-induced renal damage is associated with inflammation. Hydrogen sulphide (H2S) is involved in models of inflammation. This study evaluates the effect of DL-propargylglycine (PAG), an inhibitor of endogenous H2S formation, on the renal damage induced by CP. METHODS: The rats were injected with CP (5 mg/kg, i.p.) or PAG (5 mg/kg twice a day, i.p.) for 4 days, starting 1 h before CP injection. Control rats were injected with 0.15 M NaCl or PAG only. Blood and urine samples were collected 5 days after saline or CP injections for renal function evaluation. The kidneys were removed for tumour necrosis factor (TNF)-α quantification, histological, immunohistochemical and Western blot analysis. The cystathionine γ-lyase (CSE) activity and expression were assessed. The direct toxicity of H(2)S in renal tubular cells was evaluated by the incubation of these cells with NaHS, a donor of H2S. RESULTS: CP-treated rats presented increases in plasma creatinine levels and in sodium and potassium fractional excretions associated with tubulointerstitial lesions in the outer medulla. Increased expression of TNF-α, macrophages, neutrophils and T lymphocytes, associated with increased H2S formation rate and CSE expression, were also observed in the outer medulla from CP-injected rats. All these alterations were reduced by treatment with PAG. A direct toxicity of NaHS for renal tubular epithelial cells was not observed. CONCLUSIONS: Treatment with PAG reduces the renal damage induced by CP. This effect seems to be related to the H2S formation and the restriction of the inflammation in the kidneys from PAG + CP-treated rats.

Evaluation of erythrocyte dysmorphism by light microscopy with lowering of the condenser lens: A simple and efficient method.

AIM: To demonstrate that the evaluation of erythrocyte dysmorphism by light microscopy with lowering of the condenser lens (LMLC) is useful to identify patients with a haematuria of glomerular or non-glomerular origin. METHODS: A comparative double-blind study between phase contrast microscopy (PCM) and LMLC is reported to evaluate the efficacy of these techniques. Urine samples of 39 patients followed up for 9 months were analyzed, and classified as glomerular and non-glomerular haematuria. The different microscopic techniques were compared using receiver-operator curve (ROC) analysis and area under curve (AUC). Reproducibility was assessed by coefficient of variation (CV). RESULTS: Specific cut-offs were set for each method according to their best rate of specificity and sensitivity as follows: 30% for phase contrast microscopy and 40% for standard LMLC, reaching in the first method the rate of 95% and 100% of sensitivity and specificity, respectively, and in the second method the rate of 90% and 100% of sensitivity and specificity, respectively. In ROC analysis, AUC for PCM was 0.99 and AUC for LMLC was 0.96. The CV was very similar in glomerular haematuria group for PCM (35%) and LMLC (35.3%). CONCLUSION: LMLC proved to be effective in contributing to the direction of investigation of haematuria, toward the nephrological or urological side. This method can substitute PCM when this equipment is not available.

MAPK and angiotensin II receptor in kidney of newborn rats from losartan-treated dams.

Several lines of evidence suggest that angiotensin II (A-II) participates in the postnatal development of the kidney in rats. Many effects of A-II are mediated by mitogen-activated protein kinase (MAPK) pathways. This study investigated the influence that treatment with losartan during lactation has on MAPKs and on A-II receptor types 1 (AT(1)) and 2 (AT(2)) expression in the renal cortices of the offspring of dams exposed to losartan during lactation. In addition, we evaluated the relationship between such expression and changes in renal function and structure. Rat pups from dams receiving 2% sucrose or losartan diluted in 2% sucrose (40 mg/dl) during lactation were killed 30 days after birth, and the kidneys were removed for histological, immunohistochemical, and Western blot analysis. AT(1) and AT(2) receptors and p-p38, c-Jun N-terminal kinases (p-JNK) and extracellular signal-regulated protein kinases (p-ERK) expression were evaluated using Western blot analysis. The study-group rats presented an increase in AT(2) receptor and MAPK expression. In addition, these rats also presented lower glomerular filtration rate (GFR), greater albuminuria, and changes in renal structure. In conclusion, newborn rats from dams exposed to losartan during lactation presented changes in renal structure and function, which were associated with AT(2) receptor and MAPK expression in the kidneys.