RESUMO
During ischemic acute kidney injury (AKI), loss of cytoskeletal integrity and disruption of intercellular junctions are rapid events in response to ATP depletion. Angiotensin II type 2 receptor (AT2R) is overexpressed in injury situations and its stimulation by angiotensin II (AngII) is related to beneficial renal effects. Its role on ischemic AKI has not been deeply studied. The aim of the present study was to investigate whether pretreatment with the AT2R agonist, C21, prevents ischemic renal epithelial cell injury. Studies in a model of 40 min of renal ischemia followed by 24 h of reperfusion (IR) in rats demonstrated that C21 pretreatment attenuated renal dysfunction and induced better preservation of tubular architecture. In addition, we studied the expression of Rho GTPases, RhoA and Cdc42, since they are key proteins in the regulation of the actin cytoskeleton and the stability of epithelial intercellular junctions. IR downregulated RhoA and Cdc42 abundance in rat kidneys. C21 pretreatment prevented RhoA reduction and increased Cdc42 abundance compared to controls. We also used an in vitro model of ATP depletion in MDCK cells grown on filter support. Using immunofluorescence we observed that in MDCK cells, C21 pretreatment prevented the ATP depletion-induced reduction of actin in brush border microvilli and in stress fibers. Moreover, C21 prevented membrane E-cadherin reduction, and RhoA and Cdc42 downregulation. The present study describes for the first time a renoprotective effect of the AT2R agonist, C21, against AKI, and provides evidence supporting that stimulation of AT2R triggers cytoprotective mechanisms against an ischemic event.
Assuntos
Injúria Renal Aguda/prevenção & controle , Anti-Inflamatórios/uso terapêutico , Imidazóis/uso terapêutico , Túbulos Renais/efeitos dos fármacos , Receptor Tipo 2 de Angiotensina/agonistas , Sulfonamidas/uso terapêutico , Tiofenos/uso terapêutico , Urotélio/efeitos dos fármacos , Injúria Renal Aguda/metabolismo , Injúria Renal Aguda/patologia , Animais , Anti-Inflamatórios/farmacologia , Cães , Relação Dose-Resposta a Droga , Imidazóis/farmacologia , Isquemia/tratamento farmacológico , Isquemia/metabolismo , Isquemia/patologia , Rim/efeitos dos fármacos , Rim/metabolismo , Rim/patologia , Túbulos Renais/metabolismo , Túbulos Renais/patologia , Células Madin Darby de Rim Canino , Masculino , Ratos , Ratos Wistar , Receptor Tipo 2 de Angiotensina/metabolismo , Sulfonamidas/farmacologia , Tiofenos/farmacologia , Urotélio/metabolismo , Urotélio/patologiaRESUMO
The urinary bladder is a target organ of several toxic agents. Exposure to those agents induces mild-to-severe changes, which can be evaluated by different methods. Among them, the scanning-electron microscopy (SEM) is the "gold standard" for characterizing urothelial damage since it provides high-definition images, making it possible to detect early lesions on the surface of the urinary bladder. In addition, molecular technologies allow detecting changes in genetic material and investigating the interaction between genes and environmental stress in disease causation. The urinary bladder epithelium is where the most common type of bladder cancer occurs in humans, that is, the transitional-cell carcinoma (TCC). In animal models, the TCC can be similar to the disease in humans. Techniques to evaluate urothelium in experimental models aid in the comprehension of risk factors for urothelial carcinogenesis.
Assuntos
Técnicas Genéticas , Microscopia Eletroquímica de Varredura , RNA/isolamento & purificação , Bexiga Urinária/efeitos dos fármacos , Urotélio/efeitos dos fármacos , Animais , RNA/genética , Ratos , Bexiga Urinária/metabolismo , Bexiga Urinária/ultraestrutura , Urotélio/metabolismo , Urotélio/ultraestruturaRESUMO
Sufficient epidemiologic evidence has established an etiologic link between bladder cancer risk and occupational exposure as a painter to organic solvents. Currently, it remains to be established whether gene-specific promoter methylation contributes to bladder cancer development, including by enhancing chromosome breakage or loss. We investigated the effect of chronic exposure to organic solvents and paints on DNA methylation profiles in the promoter regions of four genes (GSTP1, p16(INK4a), APC and CDH1) and micronucleus (MN) frequency in exfoliated urothelial cells from voided urine from Colombian male non-smoking car painters and age-matched unexposed individuals. The exposed group had a higher percentage of individuals with >2 MNs/2000 cells compared with the unexposed group (P=0.04). Gene-specific analysis showed a significantly higher percentage of individuals with methylated GSTP1, p16(INK4a) and APC in the exposed group. Poisson regression analysis indicated that exposed individuals with methylated GSTP1 and p16(INK4a) promoters were more than twofold more likely to have an increase in MN frequency as compared with the reference. Finally, among exposed individuals with GSTP1 and p16(INK4a) methylated promoters, those with a greater age had a higher RR of increased MN frequency compared with younger exposed individuals with methylated promoters. These results support the conclusion that gene-specific promoter methylation may increase MN frequency in a dependent or independent interaction with occupational exposure to organic solvents.
Assuntos
Metilação de DNA , Testes para Micronúcleos , Exposição Ocupacional , Pintura/toxicidade , Regiões Promotoras Genéticas , Solventes/toxicidade , Urotélio/efeitos dos fármacos , Humanos , Masculino , Urotélio/citologiaRESUMO
BACKGROUND: This study aimed to evaluate the effect of long-term high-dose tibolone on the bladders and urethras of ovariectomized rats. METHODS: Bilateral ovariectomy was performed in 14 young adult rats randomly divided into 2 groups. Experimental rats (n = 9) received 1 mg/day of tibolone orally; control rats (n = 6) received a placebo. After 150 days, the bladders and urethras were removed. Bladder cell proliferation was analyzed by Ki-67 immunohistochemistry. A histomorphometric analysis was performed for epithelial thickness and the percent areas of collagen fibers and blood vessels. Data were compared using a Mann-Whitney test (significance level at p < 0.05). RESULTS: Urothelial thickness and the percent area of collagen fibers and blood vessels were not significantly different between the tibolone and control groups in the bladder and urethra. In addition, urothelium cell proliferation in the bladder showed a low immunopositivity in both groups. Furthermore, the glycogen and glycoprotein contents in urethral epithelium were slightly modified by tibolone and no change was observed in the bladder. CONCLUSION: Long-term administration of tibolone has no effect on urothelial trophism, collagen fibers, the number of vessels, or cell proliferation in the urethra and bladder of the ovariectomized rat.
Assuntos
Moduladores de Receptor Estrogênico/administração & dosagem , Norpregnenos/administração & dosagem , Ovariectomia , Uretra/efeitos dos fármacos , Bexiga Urinária/efeitos dos fármacos , Animais , Feminino , Glicogênio/análise , Glicoproteínas/análise , Ratos , Ratos Wistar , Uretra/anatomia & histologia , Bexiga Urinária/anatomia & histologia , Urotélio/anatomia & histologia , Urotélio/química , Urotélio/efeitos dos fármacosRESUMO
Radiotherapy is often used to treat prostate tumors, but the normal bladder is usually adversely affected. Using an animal model of pelvic radiation, we investigated whether glutamine nutritional supplementation can prevent radiation-induced damage to the bladder, especially in its more superficial layers. Male rats aged 3-4 months were divided into groups of 8 animals each: controls, which consisted intact animals; radiated-only rats, which were sacrificed 7 (R7) or 15 (R15) days after a radiation session (10Gy aimed at the pelvico-abdominal region); and radiated rats receiving l-glutamine supplementation (0.65g/kg body weight/day), which were sacrificed 7 (RG7) or 15 (RG15) days after the radiation session. Cells and blood vessels in the vesical lamina propria, as well as the urothelium, were then measured using histological methods. The effects of radiation were evaluated by comparing controls vs. either R7 or R15, while a protective effect of glutamine was assessed by comparing R7 vs. RG7 and R15 vs. RG15. The results showed that, in R7, epithelial thickness, epithelial cell density, and cell density in the lamina propria were not significantly affected. However, density of blood vessels in R7 was reduced by 48% (p<0.05) and this alteration was mostly prevented by glutamine (p<0.02). In R15, density of blood vessels in the lamina propria was not significantly modified. However, epithelial thickness was reduced by 25% (p<0.05) in R15, and this effect was prevented by glutamine (p<0.01). In R15, epithelial cell density was increased by 35% (p<0.02), but glutamine did not protect against this radiation-induced increase. Cell density in the lamina propria was likewise unaffected in R15. Density of mast cells in the lamina propria was markedly reduced in R7 and R15. The density was still reduced in RG7, but a higher density in RG15 suggested a glutamine-mediated recovery. Alpha-actin positive cells in the lamina propria formed a suburothelial layer and were identified as myofibroblasts. Thickness of this layer was increased in R7, but was similar to controls in RG7, while changes in R15 and RG15 were less evident. In conclusion, pelvic radiation leads to significant acute and post-acute alterations in the composition and structural features of the vesical lamina propria and epithelium. Most of these changes, however, can be prevented by glutamine nutritional supplementation. These results emphasize, therefore, the potential use of this aminoacid as a radioprotective drug.
Assuntos
Suplementos Nutricionais , Glutamina/uso terapêutico , Lesões Experimentais por Radiação/prevenção & controle , Bexiga Urinária/efeitos dos fármacos , Urotélio/efeitos dos fármacos , Animais , Glutamina/administração & dosagem , Glutamina/farmacologia , Humanos , Masculino , Lesões Experimentais por Radiação/patologia , Radioterapia , Ratos , Ratos Wistar , Bexiga Urinária/patologia , Bexiga Urinária/efeitos da radiação , Urotélio/patologia , Urotélio/efeitos da radiaçãoRESUMO
Diuron (3-(3,4-dichlorophenyl)-1,1-dimethylurea) is a substituted urea herbicide that induces rat urinary bladder urothelial tumors at high dietary levels (2500 ppm). The specific mode of action and molecular alterations triggered by diuron, however, have not been clarified. The present study evaluated the dose-dependent effects of mucosal alterations and transcriptional changes in the urinary bladder of rats exposed to diuron. Six-week-old male Wistar rats were treated with 0, 60, 125, 1250, and 2500 ppm of diuron in the diet for 20 weeks. Histologic examination showed urothelial hyperplasia present in rats treated with either 1250 or 2500 ppm of diuron but not 60 or 125 ppm. Comprehensive gene expression analyses of urothelial cell RNA were conducted using Affymetrix microarrays. The numbers of differentially expressed transcripts between each treatment group and control increased with diuron dose. Based on similar histology and gene expression responses, the treatment groups were regrouped into a high-dose (1250 and 2500 ppm) and low-dose group (60 and 125 ppm). These data suggest that persistent exposure to high dietary concentrations of diuron induces oxidative stress, increases cellular metabolism, and enhances cell death that is associated with sustained urothelial hyperplasia.
Assuntos
Diurona/toxicidade , Herbicidas/toxicidade , Transcriptoma , Bexiga Urinária/efeitos dos fármacos , Animais , Carcinógenos/toxicidade , Dieta , Relação Dose-Resposta a Droga , Concentração de Íons de Hidrogênio , Hiperplasia/patologia , Masculino , Análise em Microsséries , Estresse Oxidativo , RNA/isolamento & purificação , Ratos , Ratos Wistar , Transcrição Gênica , Bexiga Urinária/patologia , Urotélio/citologia , Urotélio/efeitos dos fármacos , Urotélio/patologiaRESUMO
The urothelium covering the luminal surface of the urinary bladder has developed an efficient permeability barrier that protects it against the back-flow of toxins eliminated in the urine. The subapical endocytic vesicles containing the urinary bladder fluid phase are formed during the micturition cycle by endocytosis processes of the superficial cells. In normal conditions, the permeability barrier of the endocytic vesicles blocks the passage of the fluid phase to the cellular cytoplasm and the fluid is recycled to the bladder lumen. The aim of this work was to investigate the alteration of the endocytic vesicle membrane permeability barrier to toxins such as iAs (inorganic arsenic) administered in drinking water. By using an induced endocytosis model and the fluorescence requenching technique, it is shown that the exposure of rats to ingestion of water containing iAs not only induced pre-cancerous morphological changes, but allowed the differential leakage of an endocytosed fluorescent marker, HPTS, and its quencher, DPX, (hydroxypyrene-1,3,6-trisulfonic acid and p-xylene-bis-pyridinium bromide, respectively) out of the vesicular lumen. The leakage of the cationic DPX was almost complete, while the release of the anionic HPTS molecule was partial and higher in arsenic-treated-rats than in controls. Such membrane alteration would allow the toxins to elude the permeability barrier and to leak out of the endocytic vesicles, thus establishing a "bypass" to the permeability barrier. The retention of As in the urinary bladder, assessed by synchrotron radiation X-ray fluorescence spectrometry (SR-µXRF), was lower than the kidney accumulation of arsenic previously observed by our group and was accompanied by altered concentrations of K, Ca, Fe, Cu and Zn, all ions related to cellular metabolism. The results support the hypothesis that low amounts of endocytosed As can accumulate in the interior of the urothelial superficial cells and initiate the cytotoxic effects reflected in the morphological alterations observed.
Assuntos
Arsênio/toxicidade , Ácidos Graxos/metabolismo , Lesões Pré-Cancerosas/metabolismo , Vesículas Transportadoras/metabolismo , Bexiga Urinária/metabolismo , Urotélio/metabolismo , Animais , Arsênio/administração & dosagem , Arsênio/metabolismo , Permeabilidade da Membrana Celular/efeitos dos fármacos , Masculino , Lesões Pré-Cancerosas/induzido quimicamente , Lesões Pré-Cancerosas/patologia , Ratos , Ratos Wistar , Vesículas Transportadoras/efeitos dos fármacos , Bexiga Urinária/efeitos dos fármacos , Bexiga Urinária/patologia , Urotélio/efeitos dos fármacos , Urotélio/patologiaRESUMO
The decline in sex hormone levels that accompanies the menopause has substantial effects on the tissues of the urogenital system, leading to atrophic changes. These changes can have negative effects on sexual and urinary function. The authors evaluate the repercussion of hypoestrogenism and sexual steroids on some elements of the pelvic floor and lower urinary tract. They summarize their research work and review significant published papers. They emphasize the changes in urinary mucosae, periurethral vessels, muscular layer, connective tissue, gene expression, autonomic nervous system receptors, as well as the main clinical aspects involved.
Assuntos
Estrogênios/deficiência , Sistema Urinário/metabolismo , Urotélio/fisiologia , Envelhecimento/fisiologia , Animais , Atrofia , Colágeno/análise , Colágeno/efeitos dos fármacos , Ciclo-Oxigenase 1/genética , Terapia de Reposição de Estrogênios , Estrogênios/fisiologia , Estrogênios/uso terapêutico , Matriz Extracelular/metabolismo , Feminino , Expressão Gênica , Glicosaminoglicanos/metabolismo , Humanos , Ácido Hialurônico/metabolismo , Microcirculação/efeitos dos fármacos , Músculo Liso/efeitos dos fármacos , Neovascularização Fisiológica/efeitos dos fármacos , Diafragma da Pelve/irrigação sanguínea , RNA Mensageiro/metabolismo , Receptores Muscarínicos/efeitos dos fármacos , Receptores Muscarínicos/fisiologia , Moduladores Seletivos de Receptor Estrogênico/uso terapêutico , Incontinência Urinária/tratamento farmacológico , Incontinência Urinária/fisiopatologia , Sistema Urinário/irrigação sanguínea , Urotélio/efeitos dos fármacos , Prolapso Uterino/fisiopatologia , Vagina/metabolismo , Vagina/patologia , Fator A de Crescimento do Endotélio Vascular/efeitos dos fármacos , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo , Microglobulina beta-2/genéticaRESUMO
OBJECTIVE: To investigate biomarkers of cytogenotoxicity in women exposed to mercury in a mining area. Mercury has been associated with cytogenotoxicity in human and animal models but has not been considered carcinogenic in humans, even though genotoxic effects following exposure to inorganic mercury compounds have been observed. METHODS: A cross-sectional study and micronucleus assay in uroepithelial cells were performed in 104 women (12-84 years of age). First urine void samples were taken to determine creatinine-adjusted mercury levels in urine (HgUCr), to isolate cells and to quantify cytogenetic damage. RESULTS: The geometric average level for HgUCr was 4.9 microg/g (range, 0.4-85). In the generalised linear model, after controlling for other co-variables, we observed that for each 10 microg/g increase in HgUCr, the OR of developing a genotoxic effect was 2.37 (95% CI 1.79 to 2.84), while for cytotoxic damage in uroepithelial cells the OR was 1.34 (95% CI 1.10 to 1.79). These results suggest a possible association between cytogenotoxicity and HgUCr. CONCLUSION: Living in a mining area with exposure to inorganic mercury and having higher mercury levels in urine increased the risk of developing uroepithelial cytogenotoxicity.
Assuntos
Mercúrio/toxicidade , Mineração , Urotélio/efeitos dos fármacos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Estudos Transversais , Exposição Ambiental/efeitos adversos , Exposição Ambiental/análise , Monitoramento Ambiental/métodos , Células Epiteliais/efeitos dos fármacos , Feminino , Humanos , Mercúrio/urina , Micronúcleos com Defeito Cromossômico/induzido quimicamente , Pessoa de Meia-Idade , Testes de Mutagenicidade/métodos , Poluentes do Solo/análise , Poluentes do Solo/toxicidade , Urotélio/citologia , Adulto JovemRESUMO
Haemolytic uraemic syndrome (HUS) is a rare thromboembolic complication observed in patients with cancer. It is characterised by the clinical triad of acute renal failure, microangiopathic haemolytic anaemia and thrombocytopaenia. It may be associated with a variety of aetiologies, including chemotherapeutic agents such as mitomycin, cisplatin, bleomycin, 5-fluorouracil and, most recently, gemcitabine. We report a 70-year-old patient treated with gemcitabine who developed haemolytic uraemic syndrome.