Rhein alleviates renal interstitial fibrosis by inhibiting tubular cell apoptosis in rats

BACKGROUND: Ureteral obstruction causes injury of the renal tissues and can irreversibly progress to renal fibrosis, with atrophy and apoptosis of tubular cells. The goal of the current study was to examine the effects of rhein on the apoptosis o renal tubular cells as well as renal fibrosis using a rodent model of unilateral ureteral obstruction (UUO). METHODS: UUO was induced through ureteral ligation, then animals received treatments with rhein or vehicle. The control rats only received sham operation. The renal tissue was harvested 1 week after surgery for assessment of kidney fibrosis. RESULTS: The expressions of collagen I and α-smooth muscle actin (α-SMA), as well as the severity of renal tubular apoptosis and fibrosis were time-dependently increased following UUO. Treatments with rhein partially inhibited such responses. Renal interstitial fibrosis was associated with STAT3 (signal transducer and activator of transcription 3) phosphorylation as well as altered expressions of Bax and Bcl2, both apoptosis-related proteins. Treatment with rhein also partly blocked these responses. CONCLUSION: These findings demonstrated that rhein mitigated apoptosis of renal tubular cell as well as renal fibrosis in a UUO rodent model. This curative effect is likely mediated via suppression of STAT3 phosphorylation.

Histochemical and immunohistochemical differences between solitary oral fibroma and fibrous papule of the face

Abstract: Background: The morphological similarities between fibrous papules of the face and multiple sporadic oral fibromas were mentioned long ago and a relationship between them has been reported in the literature. Objective: The aim of this study was to evaluate the participation of mast cells, elastin and collagen in a series of oral fibromas and fibrous papules of the face in order to better understand the possible role of these factors in fibrosis and the formation of these lesions. Methods: Thirty cases of oral fibroma involving the buccal mucosa and 30 cases of fibrous papules of the face were selected. Tissue samples were submitted to picrosirius red staining and immunohistochemistry using anti-elastin and anti-tryptase antibodies. Results: The percentage of tryptase-positive mast cells and expression of elastin were higher in cases of fibrous papules of the face (p < 0.05). In contrast, a higher intensity of collagen deposition was observed in oral fibromas. The results showed mast cell accumulation and higher elastin synthesis in fibrous papules of the face, and mast cell accumulation with higher collagen fiber synthesis in oral fibromas. Conclusion: These findings support the hypothesis that mast cells influence the development and growth of these lesions through different mechanisms.

Superoxide overproduction and kidney fibrosis: a new animal model / Produção aumentada de superóxido e fibrose renal: novo modelo animal

Objective To establish whether the mutation in the Immp2L gene induces renal fibrosis and whether aging exacerbates renal morphology in mice. Methods Female mutant mice with mutation in the inner mitochondrial membrane peptidase 2-like protein at 3 and 18 months of age were used. Renal fibrosis was analyzed using classic fibrosis score, Masson’s trichrome staining, and analysis of profibrotic markers using real time polymerase chain reaction (superoxide dismutase 1, metalloproteinase-9, erythropoietin, transforming growth factor beta), and immunostaining (fibroblasts and Type IV collagen). Oxidative stress markers were determined by immunohistochemistry. The number of renal apoptotic cells was determined. Renal function was estimated by serum creatinine. Results Young mutant mice had significantly more glomerulosclerosis than age-matched mice (p=0.034). Mutant mice had more tubular casts (p=0.025), collagen deposition (p=0.019), and collagen type IV expression (p<0.001). Superoxide dismutase 1 expression was significantly higher in young mutants (p=0.038). Old mutants exhibited significantly higher expression of the fibroblast marker and macrophage marker (p=0.007 and p=0.012, respectively). The real time polymerase chain reaction of metalloproteinase-9 and erythropoietin were enhanced 2.5- and 6-fold, respectively, in old mutants. Serum creatinine was significantly higher in old mutants (p<0.001). Conclusion This mutation altered renal architecture by increasing the deposition of extracellular matrix, oxidative stress, and inflammation, suggesting a protective role of Immp2L against renal fibrosis. .

Objetivo Estabelecer se a mutação no gene Immp2L induz à fibrose renal e se o envelhecimento exacerba a morfologia renal em camundongos. Métodos Foram usadas fêmeas de camundongos mutantes para proteína semelhante à peptidase 2 da camada interna da mitocôndria, com 3 e 18 meses de idade. Para analisar a fibrose renal, foram usados o escore clássico de fibrose, a coloração com tricrômio de Masson, e a análise de marcadores profibróticos, por meio da reação em cadeia de polimerase em tempo real (superóxido dismutase 1, metalonoproteinase-9, eritropoietina e fator transformador de crescimento beta), e a imunocoloração (fibroblastos e colágeno IV). Marcadores de estresse oxidativo foram determinados por imuno-histoquímica. O número de células apoptóticas renais foi analisado. A função renal foi estimada por creatinina sérica. Resultados Camundongos mutantes jovens apresentaram glomeruloesclerose em quantidade significativamente maior que animais da mesma idade (p=0,034). Os mutantes mostraram maior formação de cilindros tubulares (p=0,025), deposição de colágeno (p=0,019) e maior expressão de colágeno do tipo IV (p<0,001). A expressão de superóxido dismutase 1 foi maior em mutantes jovens (p=0,038). Mutantes idosas exibiram maior expressão dos marcadores de fibroblastos e macrófagos (p=0,007 e p=0,012, respectivamente). As reações da cadeia de polimerase em tempo real da metalanoproteinase-9 e da eritropoietina estavam aumentadas em 2,5 e 6 vezes, respectivamente, em mutantes idosas. A creatinina sérica foi significantemente maior em animais idosos mutantes (p<0,001). Conclusão Essa mutação alterou a arquitetura renal pelo aumento da deposição de matriz extracelular, estresse oxidativo e inflamação, sugerindo papel de proteção de Immp2L contra a fibrose renal. .

Signaling Mechanisms Regulating Fibroblast Activation, Phenoconversion and Fibrosis in the Heart.

Cardiac fibroblasts (CFs) maintain the cardiac extracellular matrix (ECM) through myocardial remodelling. The remodelling process can become dysregulated during various forms of heart disease  which leads to an overall accumulation of ECM. This results in cardiac fibrosis which increases the risk of heart failure in many patients. During heart disease, quiescent CFs undergo phenoconversion to an activated cell type called cardiac myofibroblasts (CMFs). Factors influencing phenoconversion include transforming growth factor β (TGF-β) which via SMADs (small mothers against decapentaplegic) activates the myofibroblast marker gene αSMA (α smooth muscle actin). Signaling molecules as diverse as NAD(P)H oxidase 4 (Nox4) and Wnt have been found to interact with TGF-β signalling via SMADs. Pathways, including FAK/TAK/JNK and PI3K/Akt/rac have also been implicated in activating phenoconversion of fibroblasts. Another major contributor is mechanical stress exerted on CFs by ECM changes, which involves activation of ERK and subsequent αSMA expression. Other factors, such as the mast cell protease tryptase and the seeding density also affect the phenoconversion of fibroblast cultures in vitro. Further, reversal of myofibroblast phenotype has been reported by a negative regulator of TGF-β, Ski, as well as the hormone relaxin and the second messenger cAMP. Targeting the signaling molecules involved in promoting phenoconversion of CFs to CMFs presents a possible method of controlling cardiac fibrosis. Here, we provide a brief review of signaling mechanisms responsible for phenoconversion and identify critical targets for the treatment of cardiac fibrosis.

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.

p53 immunostaining pattern in Brazilian patients with hepatocellular carcinoma

O carcinoma hepatocelular (CHC) é um importante tipo de câncer relacionado etiologicamente a alguns vírus, carcinógenos químicos e outros fatores ambientais que causam danos crônicos ao fígado em humanos. A freqüência de mutação do gene p53 em CHC é altamente heterogênea (0-52 por cento) nos diversos países. OBJETIVO: O objetivo deste estudo foi determinar, imuno-histologicamente, a freqüência da expressão anômala de p53 em CHCs em pacientes cirróticos versus não-cirróticos, bem como em displasia hepática e hiperplasia adenomatosa. Para isso, foram estudados 84 pacientes com carcinoma hepatocelular ou cirrose. RESULTADOS: Foram detectadas expressões do p53 alterado em 58,3 por cento dos pacientes com CHC graus III-IV, contrastando com os 22,2 por cento dos pacientes com CHC graus I-II (p = 0,02). Áreas não tumorais, tanto nas proximidades do CHC como nos 30 casos de cirrose não mostraram expressão nuclear alterada do p53, mesmo nas displasias ou hiperplasias adenomatosas. Quando se considerou HBV, HCV ou alcoolismo nos casos estudados, não se encontrou diferença significativa. CONCLUSÃO: A elevada freqüência de imuno-expressão de p53 nesta população é próxima à relatada na China e África, tornando necessárias outras pesquisas para explicar as diferenças com os CHC estudados na Europa e na América do Norte.

Biochemical & histochemical changes relating to fibrosis following infection with Mycobacterium tuberculosis in the guinea pig.

Guinea pigs infected with M. tuberculosis were studied for parameters relating to fibrosis following infection. The infected animals were followed up to a period of 44 wk and the changes that occurred in the lung, liver and spleen were studied. Corresponding tissues from animals injected with bleomycin, an anti-mitotic drug which has the ability to produce pulmonary fibrosis, served as positive controls. Tissue collagen, elastin and hexosamines were estimated biochemically. The presence of granuloma and stainable collagen in paraffin sections of these tissues was also studied. Establishment of the infection was assessed bacteriologically by culturing the viable organisms from the spleen. It was observed that a self-limiting infection was established in the guinea pigs and none of the animals died of the infection. In the infected animals, collagen, elastin and hexosamines showed an initial decrease followed by an increase. While the elastin and the hexosamine levels returned to the basal levels in all the three organs, collagen levels increased in the lung and were comparable to those of the bleomycin control. Collagen stainable by Van Gieson's method was found to be increased in the lung from the 4th wk onwards. The present report indicates the potential of adopting this system for studying mechanisms of fibrogenesis in tuberculous infection.