Renal Damage in Experimentally-Induced Cirrhosis in Rats: Role of Oxygen Free Radicals

Cirrhosis with ascites is associated with impaired renal function accompanied by sodium and water retention. Although it has been suggested that mediators such as nitric oxide play a role in the development of renal failure in this situation, other mechanisms underlying the process are not well understood. This study examined the role of oxidative stress in mediating renal damage during the development of cirrhosis in order to understand mechanisms involved in the process. It was shown that carbon tetrachloride– or thioacetamide-induced cirrhosis in rats results in oxidative stress in the kidney as seen by increased lipid peroxidation and protein oxidation, accompanied by altered antioxidant status. Cirrhosis was also found to affect renal mitochondrial function, as assessed by measurement of the respiratory control ratio, the swelling of mitochondria, and calcium flux across mitochondrial membranes. Increased lipid peroxidation and changes in lipid composition were evident in the renal brush border membranes, with compromised transport of 14C glucose across these membranes. In conclusion, renal alterations produced as a result of cirrhosis in the rat are possibly mediated by oxidative stress

Intestinal Mucosal Alterations in Rats With Carbon Tetrachloride-Induced Cirrhosis: Changes in Glycosylation and Luminal Bacteria

Spontaneous bacterial peritonitis is a major cause of mortality after liver cirrhosis. Altered permeability of the mucosa and deficiencies in host immune defenses through bacterial translocation from the intestine due to intestinal bacterial overgrowth have been implicated in the development of this complication. Molecular mechanisms underlying the process are not well known. In order to understand mechanisms involved in translocation of bacteria, this study explored the role of oxidative stress in mediating changes in intestinal mucosal glycosylation and luminal bacterial content during cirrhosis. CCl4-induced cirrhosis in rats led to prolonged oxidative stress in the intestine, accompanied by increased sugar content of both intestinal brush border and surfactant layers. This was accompanied by changes in bacterial flora in the gut, which showed increased hydrophobicity and adherence to the mucosa. Inhibition of xanthine oxidase using sodium tungstate or antioxidant supplementation using vitamin E reversed the oxidative stress, changes in brush border membrane sugar content, and bacterial adherence. In conclusion, oxidative stress in the intestine during cirrhosis alters mucosal glycosylation, accompanied by an increased hydrophobicity of luminal bacteria, enabling increased bacterial adherence onto epithelial cells. This might facilitate translocation across the mucosa, resulting in complications such as spontaneous bacterial peritonitis

Renal damage in experimentally-induced cirrhosis in rats: role of oxygen free radicals

Cirrhosis with ascites is associated with impaired renal function accompanied by sodium and water retention. Although it has been suggested that mediators such as nitric oxide play a role in the development of renal failure in this situation, other mechanisms underlying the process are not well understood. This study examined the role of oxidative stress in mediating renal damage during the development of cirrhosis in order to understand mechanisms involved in the process. It was shown that carbon tetrachloride- or thioacetamide-induced cirrhosis in rats results in oxidative stress in the kidney as seen by increased lipid peroxidation and protein oxidation, accompanied by altered antioxidant status. Cirrhosis was also found to affect renal mitochondrial function, as assessed by measurement of the respiratory control ratio, the swelling of mitochondria, and calcium flux across mitochondrial membranes. Increased lipid peroxidation and changes in lipid composition were evident in the renal brush border membranes, with compromised transport of 14C glucose across these membranes. In conclusion, renal alterations produced as a result of cirrhosis in the rat are possibly mediated by oxidative stress

Intestinal mucosal alterations in rats with carbon tetrachloride-induced cirrhosis: changes in glycosylation and luminal bacteria

Spontaneous bacterial peritonitis is a major cause of mortality after liver cirrhosis. Altered permeability of the mucosa and deficiencies in host immune defenses through bacterial translocation from the intestine due to intestinal bacterial overgrowth have been implicated in the development of this complication. Molecular mechanisms underlying the process are not well known. In order to understand mechanisms involved in translocation of bacteria, this study explored the role of oxidative stress in mediating changes in intestinal mucosal glycosylation and luminal bacterial content during cirrhosis. CCl4-induced cirrhosis in rats led to prolonged oxidative stress in the intestine, accompanied by increased sugar content of both intestinal brush border and surfactant layers. This was accompanied by changes in bacterial flora in the gut, which showed increased hydrophobicity and adherence to the mucosa. Inhibition of xanthine oxidase using sodium tungstate or antioxidant supplementation using vitamin E reversed the oxidative stress, changes in brush border membrane sugar content, and bacterial adherence. In conclusion, oxidative stress in the intestine during cirrhosis alters mucosal glycosylation, accompanied by an increased hydrophobicity of luminal bacteria, enabling increased bacterial adherence onto epithelial cells. This might facilitate translocation across the mucosa, resulting in complications such as spontaneous bacterial peritonitis

Indomethacin-induced renal damage: role of oxygen free radicals

Nonsteroidal anti-inflammatory drugs are used extensively in clinical medicine. In spite of their therapeutic utility, however, they are known to cause significant gastrointestinal and renal toxicities, circumstances that limit their use. The side effects produced in these organs have been attributed mainly to the inhibitory effect of these drugs on the activity of cyclooxygenase, a key enzyme in prostaglandin synthesis. In addition to this, in the small intestine it is known that reactive oxygen species also contribute to the enteropathy seen in response to these drugs. In the kidney, however, there is little information whether other mechanisms contribute to the renal toxicity. This study was designed to look at the possible biochemical mechanisms involved in indomethacin-induced renal damage. Rats fasted overnight were dosed with indomethacin (20 mg/kg) by gavage and sacrificed 24 hr later. Histology of the kidney showed abnormalities in the mitochondria in the proximal tubules. Evidence of oxidative stress was found in the kidney associated with mitochondrial dysfunction and neutrophil infiltration. The lipid composition in the mitochondria was also altered. Such effects were abolished by the prior administration of arginine, a donor of nitric oxide. This study, thus, suggests that one of the mechanisms by which nonsteroidal anti-inflammatory drugs induce renal damage is through oxygen free radicals possibly generated by activated neutrophils and mitochondrial dysfunction

Renal Damage in Experimentally-Induced Cirrhosis in Rats: Role of Oxygen Free Radicals

Cirrhosis with ascites is associated with impaired renal function accompanied by sodium and water retention. Although it has been suggested that mediators such as nitric oxide play a role in the development of renal failure in this situation, other mechanisms underlying the process are not well understood. This study examined the role of oxidative stress in mediating renal damage during the development of cirrhosis in order to understand mechanisms involved in the process. It was shown that carbon tetrachloride– or thioacetamide-induced cirrhosis in rats results in oxidative stress in the kidney as seen by increased lipid peroxidation and protein oxidation, accompanied by altered antioxidant status. Cirrhosis was also found to affect renal mitochondrial function, as assessed by measurement of the respiratory control ratio, the swelling of mitochondria, and calcium flux across mitochondrial membranes. Increased lipid peroxidation and changes in lipid composition were evident in the renal brush border membranes, with compromised transport of 14C glucose across these membranes. In conclusion, renal alterations produced as a result of cirrhosis in the rat are possibly mediated by oxidative stress

Fibrillary glomerulonephritis in a human immunodeficiency virus-positive, hepatitis C-negative Indian patient: Expanding the profile of renal involvement in human immunodeficiency virus infection

Highly active anti retroviral therapy (HAART) has dramatically improved life expectancy of human immunodeficiency virus (HIV) infected patients, converting HIV infection into a chronic illness with associated changes in its attendant renal complications. The past two decades have witnessed a decrease in the prevalence of HIV associated nephropathy (HIVAN), traditionally considered to be the hall mark of renal involvement in HIV infection. Simultaneously a host of other glomerular and tubulo-interstitial diseases have emerged, expanding the spectrum of HIV associated renal diseases, predominant among which is HIV associated immune complex mediated kidney diseases (HIVICK). Of the diverse glomerular diseases constituting HIVICK, fibrillary glomerulonephritis (FGN) remains a rarity, with only two existing reports to date, confined to patients co-infected with Hepatitis C virus (HCV). The pathogenetic role of HIV in these patients remains under a cloud because of previously well established association of HCV infection and FGN. We report a case of FGN in a HIV seropositive, HCV negative Indian patient, highlighting the diagnostic electron microscopy (EM) findings of FGN and strengthening the causal association of HIV with FGN. In view of increasing heterogeneity of renal complications in HIV infection, the diagnostic utility of a comprehensive renal biopsy evaluation inclusive of EM is emphasized for appropriate selection of treatment modalities

Enteroaggregative Escherichia coli infection in a rabbit model

Type strains of enteroaggregative Escherichia coli EAEC (17-2, serotype O3:H2; JM 221, serotype O92:H33), isolates from an adult and a child with diarrhoea and an asymptomatic colonised child were used to orally infect adult rabbits. The experimental animals were followed up and sacrificed at defined time periods. Colonisation of both small and large intestine was seen with all strains and isolates used. Isolates from an adult patient with diarrhoea (MP 27) and from an asymptomatic colonised child from the community (KM 1337) were recovered from the small intestine during the first week of infection and subsequently from the large intestine. A total of seven rabbits was infected with MP 27; while colonising the gastrointestinal tract of all seven rabbits, this isolate caused diarrhoea in only one. On ultrastructural examination, the rabbits infected with 17-2 showed invasion of lymphoid follicles. Bacteria were seen in intercellular spaces and within M cells, a finding that has not previously been described. It is clearly possible to produce gut colonisation by oral infection with EAEC in adult rabbits with normal flora

Retinoid metabolism during development of liver cirrhosis

The changes in retinoid metabolism have been documented in liver cirrhosis. However, the dynamic alterations in levels of this vitamin between circulation and liver during development of the liver cirrhosis are not well understood. The aim of this study was to measure retinoids in the liver and circulation in parallel, during and after development of cirrhosis induced by carbon tetrachloride and thioacetamide. Retinoid levels were measured by HPLC. A decrease in retinaldehyde and total retinol, together with an increase in retinoic acid was evident in liver from both carbon tetrachloride or thioacetamide treated rats within a month after initiation of treatment. Activity of enzymes involved in retinoid metabolism such as retinaldehyde oxidase, retinaldehyde dehydrogenase, and retinaldehyde reductase were decreased in the liver. In parallel, levels of retinol and retinaldehyde in the serum were increased while retinoic acid was decreased. This study indicates that during development of cirrhosis, there is reciprocal transfer of retinoid metabolites between the circulation and the liver

Etiology of diarrhea in patients undergoing allogeneic bone marrow transplantation in South India

Background: No studies so far have examined enteric infections in patients undergoing bone marrow transplantation (BMT) in developing countries where asymptomatic carriage and colonization with enteric pathogens is frequent. Methods: A prospective study followed 65 patients who underwent BMT in South India between 1995 and 1998. Patients were screened for enteric pathogens before transplantation, weekly during the first 4 weeks after transplantation, and during all episodes of diarrhea. Results: Enteric pathogens were found in 60% of patients before or after transplantation. Pretransplantation screening revealed asymptomatic excretion of enteric pathogens in 29% (19/65). Forty-eight percent of patients undergoing BMT developed diarrhea. Diarrhea was mainly of noninfectious origin in the first 20 days after transplantation. More than 20 days after transplantation, the major causes of diarrhea were graft-versus-host disease and infection. Parasitic infections other than Cryptosporidium did not contribute significantly to morbidity in the pre- and posttransplantation period. Rotavirus and adenoviruses were found in approximately 12% and 5% of subjects, respectively. Bacterial infections in the posttransplantation period were found to be more common in India than in developed countries. Clostridium difficile-associated diarrhea was seen in the posttransplantation period but not before transplantation. Enterotoxigenic and enterohemorrhagic Escherichia coli caused symptomatic infections in the posttransplantation period, but the association of other classes of diarrheogenic E. coli with diarrhea was doubtful. Conclusions: There was significantly higher mortality (P <0.01) in patients with symptomatic or asymptomatic gastrointestinal infections caused by bacteria than in patients with parasitic or viral infections or without enteric infections