Reticuloendothelial activation and phenotypic alteration of peripheral monocytes with enhanced liver recruitment drive liver injury secondary to yellow phosphorus.

BACKGROUND AND AIM: Monocytes and macrophages play a crucial role in the pathogenesis of acute liver failure (ALF). We aimed to study reticuloendothelial activation and its correlation with disease severity in commonly encountered yellow phosphorus (rodenticide)-induced hepatotoxicity patients. We also studied peripheral monocyte phenotype in a subset of patients. METHODS: Reticuloendothelial activation markers were analyzed and correlated with disease severity score in a prospectively collected database of yellow phosphorus-related hepatoxicity patients between 2018 and 2021. In a prospective cohort of these patients and age-matched healthy controls, peripheral blood monocyte phenotyping was performed. RESULTS: Reticuloendothelial activation markers were analyzed in 67 patients [Age: 23(12-64) years; median (range), men: 25, acute liver injury (ALI): 38, ALF: 29, model for end-stage liver disease (MELD) score: 28 (7-40)] of yellow phosphorus-induced hepatotoxicity. Serum ferritin (927; 10.3-34 807 ng/mL), sCD163 (4.59; 0.11-12.7 µg/mL), sCD25 (3050; 5.6-17 300 pg/mL) and plasma von Willebrand factor (423.5, 103-1106 IU/dL) were increased and showed significant correlation with liver disease severity assessed by MELD score (ρ = 0.29, ρ = 0.6, ρ = 0.56 and ρ = 0.46 respectively). Phenotyping and serum immune markers were performed in seven patients (M: 4; age: 27, 15-37 years; median, range; MELD score: 36, 21-40) and compared with eight healthy controls. Increase in classical monocytes and decrease in patrolling and intermediate monocyte subsets were observed in ALF cohort. HLA-DRlow CD163hi (immune exhaustion), CD64hi (immune complex-mediated response), and CCR2hi (liver homing) monocyte phenotype was noted. CONCLUSION: Altered peripheral monocyte phenotype with enhanced liver homing and macrophage activation, suggests important role of innate immune activation, and provides a potential therapeutic target, in yellow phosphorus-induced hepatotoxicity.

Improving Transplant-free Survival With Low-volume Plasma Exchange to Treat Children With Rodenticide Induced Hepatotoxicity.

Background: In a prior report, no patient with rodenticidal hepatotoxicity who met Kochi criteria (MELD score ≥36 or baseline INR ≥6 with hepatic encephalopathy) (PMID: 26310868) for urgent liver transplantation survived with medical management alone. Plasma exchange (PLEX) may improve survival in these patients. Objectives: We describe our experience with low-volume PLEX (PLEX-LV) in treating rodenticide ingestion induced hepatotoxicity in children. Methods: From prospectively collected database of rodenticidal hepatotoxicity patients managed as in-patient with department of Hepatology from December 2017 to August 2021, we retrospectively studied outcomes in children (≤18 years). Hepatotoxicity was categorized as acute liver injury (ALI, coagulopathy alone) or acute liver failure (ALF, coagulopathy and encephalopathy). Kochi criteria was used to assess need for urgent liver transplantation. The primary study outcome was one-month survival. Results: Of the 110 rodenticidal hepatotoxicity patients, 32 children (females: 56%; age: 16 [4.7-18] years; median, range) constituted the study patients. The study patients presented 4 (1-8) days after poison consumption (impulsive suicidal intent:31, accidental:1). Twenty children (62%) had ALI [MELD: 18 (8-36)] and 12 (38%) had ALF [MELD: 37 (24-45)].All children received standard medical care, including N-acetyl cysteine; ALF patients also received anti-cerebral edema measures. None of the patient families opted for liver transplantation. Seventeen children (ALI: 6, ALF: 11) were treated with PLEX-LV (3 [1-5] sessions, volume of plasma exchanged per session: 26 [13-38] ml/kg body weight) and peri-procedure low dose prednisolone.At 1 month, 28 of the 32 children (87.5%) were alive (4 ALF patients died). Of 10 children who met Kochi listing criteria for urgent liver transplantation, two children were ineligible for PLEX-LV (due to hemodynamic instability) and of the remaining 8 children treated by PLEX-LV, 6 (75%) survived. Conclusions: PLEX-LV shows promise as an effective non-liver transplant treatment in children with rodenticidal hepatotoxicity.

Low Volume Plasma Exchange and Low Dose Steroid Improve Survival in Patients With Alcohol-Related Acute on Chronic Liver Failure and Severe Alcoholic Hepatitis - Preliminary Experience.

Background: Alcohol-related acute on chronic liver failure (A-ACLF) patients have high short-term mortality and are poor candidates for steroid therapy. Plasma exchange (PLEX) improves survival in ACLF patients. We analyzed our experience with low volume PLEX (50% of plasma volume exchanged per session) and low dose steroids to treat A-ACLF patients. Methods: We retrospectively compared the efficacy of low volume PLEX and low-dose steroids with standard medical treatment (SMT) in A-ACLF patients treated at our center between November 2017 to June 2019. The primary study outcome was one-year survival. Results: Twenty-one A-ACLF patients in PLEX group [age 40 (29-56) years, median (range); MELD score 31 (29-46)] and 29 A-ACLF patients in SMT group [age 41.5 (28-63) years, MELD score 37 (21-48)] were studied. All 50 study patients had severe alcoholic hepatitis [mDF 84.7 (50-389)]. PLEX group patients had 3 (1-7) PLEX sessions with 1.5 (1.4-1.6) liters of plasma exchanged per session and oral Prednisolone 20 mg daily, tapered over 1 month. Kaplan Meier analysis showed better survival over 1 year in the PLEX group compared to the SMT group (P = 0.03). There was renal dysfunction in 10 patients in the PLEX group, which normalized in six patients after PLEX. Conclusion: In this preliminary report, compared to SMT, low volume PLEX and low dose steroid improved survival over one year in A-ACLF patients with severe alcoholic hepatitis. In patients with renal dysfunction, 60% showed improvement in renal function with PLEX. Studies with a larger number of patients are needed to validate these results.

Exocrine Pancreatic Insufficiency Following Gastric Resectional Surgery-is Routine Pancreatic Enzyme Replacement Therapy Necessary?

The data on exocrine pancreatic insufficiency (EPI) following gastric resectional surgery is variable, ranging from 26% to as high as 100%. This study aimed to document symptomatic EPI following gastric resectional surgery and to objectively document EPI, by fecal elastase (FE) testing. This was a cross-sectional study among patients undergoing gastric resection for adenocarcinoma of the stomach, at the Upper Gastrointestinal Surgical Unit at the Christian Medical College Hospital, Vellore, India. A detailed questionnaire was administered to the patients in the postoperative period, to evaluate clinical symptoms of EPI. Further, study participants were tested for FE pre- and postoperatively. Of the 60 patients in this study, the postoperative questionnaire administered to all patients during follow up. None showed symptoms suggestive of EPI. Pre- and post-operative FE testing were feasible in 27 of the 60 patients, which showed a 33% incidence of EPI. None of the patients had clinical symptoms of EPI, following gastric resectional surgery, on short-term follow-up. However, more than a third of the patients tested developed asymptomatic EPI after gastric resectional surgery, based on FE testing. This may be explained by the fact that in the early postoperative period, EPI following gastric resectional surgery perhaps has a mild, subclinical presentation. Therefore routine pancreatic supplementation after gastric resectional surgery may not be necessary. However, one needs to carefully look for worsening of symptoms of EPI on long-term follow-up, which may necessitate appropriate investigations followed by pancreatic enzyme replacement therapy.

Reticuloendothelial activation correlates with disease severity and predicts mortality in severe alcoholic hepatitis.

BACKGROUND: Overactivation of reticuloendothelial cells lining liver sinusoids - Kupffer cells (macrophages) and sinusoidal endothelial cells - may narrow the sinusoidal lumen, impair perfusion in liver microcirculation and contribute to disease severity in alcoholic hepatitis. AIM: The aim of the article was to assess reticuloendothelial activation in patients with severe alcoholic hepatitis (SAH). METHODS: In SAH patients, we prospectively studied baseline reticuloendothelial activation markers [serum ferritin, sCD163 and plasma von Willebrand factor (VWF) antigen] and Macrophage Activation Syndrome (MAS) criteria, correlated them with disease severity scores [model for end-stage liver disease (MELD) and Sequential Organ Failure Assessment (SOFA) scores] and analyzed their ability to predict survival over a 90-day follow-up period. RESULTS: A total of 50 SAH patients [45 (37-49) years, median (interquartile range), 49 males, discriminant function, 76.2 (54.5-106.6); MELD score, 30 (26.2-36)] were studied. 41 SAH patients (82%) had ferritin >500 ng/mL, and all (100%) had markedly raised sCD163 and VWF levels. The median sCD163 level was 10-fold higher than healthy controls and the median VWF level was 5-fold above the upper limit of normal. In total, 37 SAH patients (74%) met MAS criteria. Reticuloendothelial activation markers correlated with MELD and SOFA scores (P < 0.05). VWF was an independent marker to predict mortality in SAH [adjusted hazard ratio, 1.002 (1.000-1.004)]. CONCLUSIONS: The reticuloendothelial system was markedly activated and correlated with disease severity scores in SAH patients.VWF predicted short-term mortality independent of MELD and sCD163. Further larger multicentric studies are needed to validate these findings.

Clinical Evaluation of a Polyherbal Nutritional Supplement in Dyslipidemic Volunteers.

Ten important plant parts routinely used in South Indian ethnic food preparation as spices and condiments were investigated for their potential antidyslipidemic properties. The aim of the study was to characterize the biochemical properties of the polyherbal formulation (nutritional supplement) and evaluate its use to control dyslipidemia in patients. Phytochemical evaluation, in vitro α-amylase inhibitory assay, and high performance thin layer chromatography (HPTLC) fingerprinting were carried out with alcoholic extracts of all 10 individual plants and with the nutritional supplement. Investigation in human volunteers was conducted to evaluate the effect on dyslipidemia as measured by serum lipid biomarkers. Sixty-five volunteers were recruited for this study. Biomarker values at baseline and at 6th visit (end of review, 8/9 months) were compared to assess the usefulness of the nutritional supplement in the normalization of lipid biomarkers. In the qualitative analysis of metabolites, the results revealed the presence of various bioactive primary and secondary metabolites that might be responsible for their medicinal attributes. In human volunteers, after supplement intake along with standard therapy, we observed significant decrease in serum cholesterol, triglyceride, low-density lipoprotein (LDL), and very low-density lipoprotein (VLDL) levels. High-density lipoprotein (HDL) level did not change in test patient volunteers. Reductions in hemoglobin A1C (HBA1C) and postprandial blood sugar levels were observed; the difference was not statistically significant. We believe that the polyherbal formulation of 10 medicinal plants has potent antidyslipidemic activity. Our results contribute for the first time toward documentation of augmented dyslipidemia control by use of the formulation.

Plasma hydrogen sulphide does not predict severity of acute pancreatitis in humans.

The primary aim of this study was to assess the usefulness of plasma hydrogen sulphide (H2S) level at admission as a predictor of severity of acute pancreatitis. The secondary aims were to examine whether the level of H2S after 48 h correlated with severity and whether level of H2S correlated with pulmonary, renal or infectious complications. Plasma hydrogen sulphide was measured within 24 h of admission and 48 h later, in patients with acute pancreatitis. Patients were classified as having mild or severe pancreatitis, and H2S levels in the two groups were compared. A total of 55 patients had H2S estimation carried out within 24 h of admission. H2S levels were similar in patients with mild (mean 31.8 ± 18.8, range 7.1 to 81.4 µmol/L) and severe pancreatitis (mean 28.2 ± 21.6, range 6.1 to 74.4 µmol/L; p = 0.339). There was no difference found between the groups after 48 h (mild n = 28, mean 26.8 ± 19.4 µmol/L, and severe n = 20, mean 34.6 ± 21.0 µmol/L; p = 0.127). There was also no difference in the levels between patients with or without lung injury, kidney injury or sepsis. Performing H2S estimation to predict severity in acute pancreatitis is not beneficial.

Pregnancy-related liver disorders.

Pregnancy-related liver disorders accounted for 8% of all maternal deaths at our center from 1999 to 2011. Of the three pregnancy-related liver disorders (acute fatty liver of pregnancy (AFLP), HELLP (Hemolysis, elevated liver enzymes, low platelets) syndrome and pre-eclamptic liver dysfunction, which can lead to adverse maternal and fetal outcome, AFLP is most typically under - diagnosed. Risk of maternal death can be minimised by timely recognition and early/aggressive multi-specialty management of these conditions. Urgent termination of pregnancy remains the cornerstone of therapy for some of these life threatening disorders, but recent advancements in our understanding help us in better overall management of these patients. This review focuses on various aspects of pregnancy-related liver disorders.

Retinoid metabolism in the small intestine during development of liver cirrhosis.

BACKGROUND AND AIMS: Retinoids are important mediators of cellular differentiation and proliferation in various epithelia of the body including the small intestine. Though alterations in intestinal epithelial cell proliferation have been noted in liver cirrhosis, mechanisms involved in the process are not well understood. This study examined the levels of various retinoids and retinoid-metabolizing enzymes in the small intestine during development of liver cirrhosis. METHODS: Four groups of animals were used (control, phenobarbitone control, thioacetamide and carbon tetrachloride treatment). Twice-weekly intragastric or i.p. administration of carbon tetrachloride or thioacetamide, respectively, produced liver cirrhosis after 3 months, which was confirmed through histology and serum markers. Retinoid levels were measured by high-performance liquid chromatography. RESULTS: A decrease in the levels of retinal, retinoic acid and retinol was evident in the intestine by 3 months, when cirrhosis was evident histologically, and these remained low until 6 months. A decrease in the activities of retinaldehyde oxidase, retinaldehyde reductase and retinol dehydrogenase was also seen in intestine from cirrhotic rats. CONCLUSION: These results suggest that altered retinoid metabolism in the intestine of cirrhotic rats might have an influence on changes in intestinal epithelial cell differentiation, seen in liver cirrhosis.

Curcumin attenuates indomethacin-induced oxidative stress and mitochondrial dysfunction.

Oxidative stress and mitochondrial dysfunction have been implicated in the pathogenesis of indomethacin-induced enteropathy. We evaluated the potential of curcumin, a known cytoprotectant, as an agent to protect against such effects. Rats were pretreated with curcumin (40 mg/kg by intra-peritoneal injection) before administration of indomethacin (20 mg/kg by gavage). One hour later, the small intestine was isolated and used for assessment of parameters of oxidative stress. Mitochondria, brush border membranes (BBM) and surfactant-like particles (SLP) were also isolated from the tissue. Mitochondria were used for assessment of functional integrity, estimation of products of lipid peroxidation and lipid content. BBM were used for estimation of products of lipid peroxidation and lipid content, while the SLP were used for measurement of lipid content. The results showed that oxidative stress and mitochondrial dysfunction occurred in the small intestine of indomethacin-treated rats. Pre-treatment with curcumin was found to ameliorate these drug-induced changes. Significant changes were seen in some of the lipids in the mitochondria, BBM and SLP in response to indomethacin. However, curcumin did not have any significant effect on these drug-induced changes. We conclude that curcumin, by attenuating oxidative stress and mitochondrial dysfunction, holds promise as an agent that can potentially reduce NSAID-induced adverse effects in the small intestine.

Spontaneous bacterial peritonitis results in oxidative and nitrosative stress in ascitic fluid.

BACKGROUND AND AIM: Spontaneous bacterial peritonitis (SBP) is a major complication of liver cirrhosis and accounts for significant mortality. Although oxygen free radicals and nitric oxide been implicated in the pathophysiology of liver cirrhosis, information on their role during the development of SBP is scarce. This study examined these active species in ascitic fluid from patients with SBP, and in response to treatment. METHODS: Forty-nine consecutive patients with cirrhosis and ascitic fluid neutrophil counts less than 250/cumm were studied as controls. Another 21 patients whose ascitic neutrophil count exceeded 250/cumm were treated as cases. Ascitic fluid was collected from these patients at entry and 48 h after treatment with antibiotics. Nitrate and markers of oxidative stress such as malondialdehyde, protein carbonyl content and total and protein thiols were measured. RESULTS: A significant increase in malondialdehyde and protein carbonyl levels was seen in ascites from patients with SBP when compared to controls. This was accompanied by a decrease in total thiols and protein thiols. In addition, there was a significant increase in ascitic fluid nitrate in patients with SBP when compared to control patients. After antibiotic treatment, malondialdehyde, protein carbonyl and nitrate levels dropped back towards control values, and total thiols also recovered. CONCLUSIONS: This study demonstrated the presence of oxidative stress in ascitic fluid from patients with SBP, and showed that ascitic fluid nitrate may be a marker for diagnosing SBP and a useful index in determining therapeutic response to antibiotic treatment.

Oxidative stress in experimental liver microvesicular steatosis: role of mitochondria and peroxisomes.

BACKGROUND: Hepatic microvesicular steatosis is a clinical manifestation seen in a number of liver diseases. Although the role of mitochondrial beta-oxidation in the development of the disease has been well studied, information on lipid peroxidative damage in liver subcellular organelles is scarce. The present study looked at oxidative stress in hepatic peroxisomes and microsomes in microvesicular steatosis, using an animal model of the disease. METHODS: Rats were given i.p. injections of sodium valproate (700 mg/kg bodyweight) to induce microvesicular steatosis, which was confirmed by histology. RESULTS: Oxidative stress was evident in liver in steatosis, accompanied by structural and functional alterations in hepatic mitochondria. Alterations in lipid composition, with decreased phosphatidyl choline and ethanolamine and increased lysophosphatidyl choline and ethanolamine, were seen. An increase in triglyceride content was also seen. In addition, increased lipid peroxidation was also evident in peroxisomes and microsomes from steatotic rats. Pretreatment with clofibrate results in partial reversal of changes produced by valproate. CONCLUSIONS: These results suggest that in addition to impaired mitochondrial beta-oxidation, oxidative stress is also seen in the hepatic peroxisomes and microsomes during microvesicular steatosis.

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.

Oxidative stress in the development of liver cirrhosis: a comparison of two different experimental models.

BACKGROUND/AIMS: Oxidative stress has been implicated in liver cirrhosis. Carbon tetrachloride and thioacetamide are the most widely used models to develop cirrhosis in rats and the present study compares oxidative stress in the liver induced by these compounds at different stages of cirrhosis development. METHODS: Twice-weekly intragastric or intraperitoneal administration of carbon tetrachloride or thioacetamide, respectively, produced liver cirrhosis after 3 months. Histology, serum markers and hepatic hydroxy proline content confirmed the cirrhosis. RESULTS: An increase in oxidative stress parameters was seen in mitochondria, peroxisomes and microsomes from the liver after carbon tetrachloride or thioacetamide treatment. Oxidative stress was more severe in carbon tetrachloride treated animals than thioacetamide. Mild oxidative stress was evident at 1 and 2 months of treatment and a significant increase was seen by 3 months of treatment with either compound. By this time, frank liver cirrhosis was also observed. CONCLUSIONS: These results suggest that evidence of oxygen free radicals is also found early in the development of fibrosis and cirrhosis in both models.

Mild whole-body heat stress alters retinoid metabolism in the rat small intestine.

Mild heat treatment can modulate metabolism and prevent stress-induced alterations in cells and tissues. Retinoids are known to influence cellular metabolism and are essential for growth and differentiation, particularly of epithelial tissue. This study examines the effect of mild heat treatment on retinoid alterations in enterocytes in the rat small intestine. Heat treatment changed the differentiation pattern of enterocytes along the villus-crypt axis, accompanied by increases in retinol, retinaldehyde, and retinoic acid in proliferating crypt cells. Activities of retinoid metabolizing enzymes such as retinaldehyde oxidase and retinaldehyde reductase were also increased. These results suggest that mild heat treatment can alter retinoid metabolism in the small intestine, which might influence epithelial cell proliferation and differentiation.

Alterations in the intestinal glycocalyx and bacterial flora in response to oral indomethacin.

Nonsteroidal anti-inflammatory drugs (NSAIDs), used extensively in clinical medicine, tend to cause adverse effects in the gastrointestinal tract. Earlier work has shown that oral administration of indomethacin produced oxidative damage in the small intestine and attenuation of the glycocalyx layer of the mucosa. The present study assessed, in greater detail, the alterations produced in the glycocalyx of rat small intestinal mucosa in response to indomethacin, with specific reference to surfactant-like particles (SLP) and brush border membranes (BBM). Changes in gut flora in response to the drug were also studied, as it has been shown that luminal bacteria play a role in the pathogenesis of NSAID-induced intestinal damage. The levels of sugars such as sialic acid, fucose, hexose and hexosamine were increased in SLP and decreased in the BBM following indomethacin treatment, with the effects being maximal 24h after the administration of the drug. The composition of lipids in the SLP was also found to be altered. There was a significant increase in the number of bacteria in the luminal contents of the small intestine and caecum in these animals, as compared with controls. The number of bacteria adherent to the intestinal mucosa was also significantly higher in the drug-treated group. In vitro studies revealed that there was an increased tendency for bacteria to adhere to SLP isolated from indomethacin-treated rats. These results suggest that alterations in glycosylation of SLP and BBM in response to indomethacin, along with qualitative and quantitative changes in the luminal bacterial flora, may facilitate translocation of bacteria into the mucosa. These changes may contribute to the enteropathy observed as a result of NSAID treatment.

Retinoid metabolism in the rat small intestine.

Vitamin A (retinol) is essential for epithelial cell growth, differentiation and proliferation. The absorption of retinol occurs in the small intestine, and the metabolism of this vitamin is not well studied in this organ. The intestinal epithelium has a high rate of cell proliferation and differentiation, and the present study looked at the level of retinoids and metabolizing enzymes involved in their interconversion along the villus-crypt axis under normal conditions. Intestine was removed from control rats, and enterocytes at various stages of maturation and differentiation were quantified by the metal chelation method. Using HPLC, various retinoid concentrations in the cell homogenate and the metabolizing enzymes in the cytosol were quantified. The proliferating crypt cells were found to have a higher level of retinoic acid as well as of the enzymes involved in its formation, such as retinaldehyde oxidase and retinol dehydrogenase, compared with the villus cells, suggesting a possible role for this compound in intestinal epithelial cell proliferation and differentiation. The high level of retinol and high retinaldehyde reductase activity in the villus cells suggest the important role played by this enzyme in the conversion of dietary beta-carotene to retinol via retinaldehyde. In summary, this study has given for the first time a detailed analysis of the retinoid levels and metabolizing enzymes in different cell populations in the rat small intestinal epithelium.

Surgical manipulation of the intestine results in quantitative and qualitative alterations in luminal Escherichia coli.

OBJECTIVES: To look at the qualitative and quantitative changes in the luminal bacterial flora in response to surgical manipulation of the small intestine. SUMMARY BACKGROUND DATA: The barrier function of the intestine is compromised in pathologic conditions, such as shock, trauma, or surgical stress. Our earlier work has shown that surgical manipulation results in oxidative stress in the intestinal mucosa leading to permeability alterations. METHODS: Studies were done on rats, which were randomly divided into four groups (n = 8): group I, control, group II, III, IV different time periods, such as 8, 12, and 24 hours after surgical manipulation, which was simulated by opening the abdominal wall and handling the intestine. The cecal wall and cecal luminal contents were harvested under sterile conditions and processed for quantitation for aerobes and anaerobes. Adherence assays using Hep-2 cells were carried out on Escherichia coli isolated under different experimental conditions. In addition, control E. coli were exposed to superoxide or hydrogen peroxide, followed by subculture and adherence studies. RESULTS: Surgical manipulation of the intestine resulted in qualitative and quantitative alterations in the aerobic bacteria. There was an increase in the number and relative proportion of E. coli in the cecal flora, and there was also an increase in adherence of E. coli to cecal mucosa, which was confirmed by in vitro bacterial adherence studies with HEp-2 cells. These changes were maximum at 12 hours following surgical manipulation and by 24 hours, this came back to control pattern. Control E. coli after in vitro exposure to oxidants also showed increased adherence. CONCLUSION: These studies suggest that oxidative stress in the mucosa following surgical manipulation results in alterations in the luminal bacteria leading to increased bacterial adherence onto mucosal epithelium, which may contribute to postsurgical complications.

Oral glutamine attenuates indomethacin-induced small intestinal damage.

The use of NSAIDs (non-steroidal anti-inflammatory drugs), although of great therapeutic value clinically, is limited by their tendency to cause mucosal damage in the gastrointestinal tract. In the small intestine, the effects these drugs have been shown to produce include inhibition of cyclo-oxygenase, mitochondrial dysfunction and free radical-induced oxidative changes, all of which contribute to the mucosal damage seen. Glutamine is a fuel preferentially used by enterocytes and is known to contribute to maintaining the integrity of these cells. In the present study, we investigated the effect of glutamine on indomethacin-induced changes in the small intestinal mucosa. Rats were given 2% glutamine or glutamic acid or isonitrogenous amino acids, glycine or alanine, in the diet for 7 days. Indomethacin was then administered orally at a dose of 40 mg/kg of body weight. After 1 h, the small intestine was removed and used for the measurement of parameters of oxidative stress and mitochondrial and BBM (brush border membrane) function. Evidence of oxidative stress was found in the mucosa of the small intestine of drug-treated rats, as indicated by significantly increased activity of xanthine oxidase (P < 0.001) and myeloperoxidase (P < 0.001), with corresponding decreases in the levels of several free radical scavenging enzymes and alpha-tocopherol (P < 0.001 in all cases). Levels of products of peroxidation were also significantly elevated (P < 0.001 for all the parameters measured). In addition, oxidative stress was evident in isolated intestinal mitochondria and BBMs (P < 0.001 for all the parameters measured), with associated alterations in function of these organelles (P < 0.001 for all the parameters measured). Supplementation of the diet with glutamine or glutamic acid prior to treatment with indomethacin produced significant amelioration in all the effects produced by the drug in the small intestine (P < 0.001 for all the parameters measured). Glycine and alanine were found to be much less effective in these respects.