Extended Post Discharge Prophylaxis for Venous Thromboembolism Prevention After Bariatric Surgery.

PURPOSE: The utility of routine post-discharge VTE prophylaxis after bariatric surgery remains a matter of debate. While inpatient chemical prophylaxis decreases the risk of fatal pulmonary embolism, most thromboembolic events occur after discharge and carry high morbidity and mortality. To address this risk, apixaban was introduced as extended prophylaxis for 30 days after surgery. MATERIALS AND METHODS: The study ranges between 1/2014 and 7/2022. Apixaban was incorporated as routine extended prophylaxis protocol in 05/2017 and is dosed at 2.5 mg BID for 30 days. There were two study groups: those who received apixaban on discharge (n = 1443; 60%) and those who did not (n = 953; 40%). Patients with concern for postoperative bleeding (hypotension, unexplained tachycardia with hematocrit drop > 6%, hematocrit drop > 9%), or on preoperative anticoagulant/antiplatelet therapy (except aspirin), were not discharged on apixaban. Post-discharge VTE, readmission, transfusion, and reoperation rates were compared between groups. RESULTS: There were 2396 consecutive primary bariatric operations: sleeve gastrectomy (1949; 81%), Roux-en-Y gastric bypass (419; 18%), and duodenal switch (28; 1%). There were no post-discharge VTEs in patients treated with apixaban vs. five (0.5%) VTEs in patients who did not receive treatment; p = 0.02. There was a higher incidence in post-discharge bleeding events in the apixaban group (0.5 vs 0.3%; p = 0.75), mostly requiring readmission for monitoring without intervention or transfusion. In the apixaban group, one patient underwent EGD for bleeding while another required blood transfusion; there were no reoperations for bleeding. CONCLUSION: There were no post-discharge VTEs in patients who received apixaban. Treatment was associated with a higher risk of self-resolving bleeding events. This study adds to the increasing body of evidence supporting the benefit of routine, extended oral chemoprophylaxis after bariatric surgery.

Regenerative and durable small-diameter graft as an arterial conduit.

Despite significant research efforts, clinical practice for arterial bypass surgery has been stagnant, and engineered grafts continue to face postimplantation challenges. Here, we describe the development and application of a durable small-diameter vascular graft with tailored regenerative capacity. We fabricated small-diameter vascular grafts by electrospinning fibrin tubes and poly(ε-caprolactone) fibrous sheaths, which improved suture retention strength and enabled long-term survival. Using surface topography in a hollow fibrin microfiber tube, we enable immediate, controlled perfusion and formation of a confluent endothelium within 3-4 days in vitro with human endothelial colony-forming cells, but a stable endothelium is noticeable at 4 weeks in vivo. Implantation of acellular or endothelialized fibrin grafts with an external ultrathin poly(ε-caprolactone) sheath as an interposition graft in the abdominal aorta of a severe combined immunodeficient Beige mouse model supports normal blood flow and vessel patency for 24 weeks. Mechanical properties of the implanted grafts closely approximate the native abdominal aorta properties after just 1 week in vivo. Fibrin mediated cellular remodeling, stable tunica intima and media formation, and abundant matrix deposition with organized collagen layers and wavy elastin lamellae. Endothelialized grafts evidenced controlled healthy remodeling with delayed and reduced macrophage infiltration alongside neo vasa vasorum-like structure formation, reduced calcification, and accelerated tunica media formation. Our studies establish a small-diameter graft that is fabricated in less than 1 week, mediates neotissue formation and incorporation into the native tissue, and matches the native vessel size and mechanical properties, overcoming main challenges in arterial bypass surgery.

Chronic Alcohol Consumption Causes Liver Injury in High-Fructose-Fed Male Mice Through Enhanced Hepatic Inflammatory Response.

BACKGROUND: Obesity and the metabolic syndrome occur in approximately one-third of patients with alcoholic liver disease (ALD). The increased consumption of fructose parallels the increased prevalence of obesity and the metabolic syndrome in the United States and worldwide. In this study, we investigated whether dietary high fructose potentiates chronic alcohol-induced liver injury, and explored potential mechanism(s). METHODS: Six-week-old male C57BL/6J mice were assigned to 4 groups: control, high fructose, chronic ethanol (EtOH), and high fructose plus chronic alcohol. The mice were fed either control diet or high-fructose diet (60%, w/w) for 18 weeks. Chronic alcohol-fed mice were given 20% (v/v) ethanol (Meadows-Cook model) ad libitum as the only available liquid from the 9th week through the 18th week. Liver injury, steatosis, hepatic inflammatory gene expression, and copper status were assessed. RESULTS: High-fructose diet and chronic alcohol consumption alone each induce hepatic fat accumulation and impair copper status. However, the combination of dietary high fructose plus chronic alcohol synergistically induced liver injury as evidenced by robustly increased plasma alanine aminotransferase and aspartate aminotransferase, but the combination did not exacerbate hepatic fat accumulation nor worsen copper status. Moreover, FE-fed mice were characterized by prominent microvesicular steatosis. High-fructose diet and chronic alcohol ingestion together led to a significant up-regulation of Kupffer cell (KC) M1 phenotype gene expression (e.g., tumor necrosis factor-α and monocyte chemoattractant protein-1), as well as Toll-like receptor 4 (TLR4) signaling gene expression, which is also associated with the up-regulation of KCs and activation marker gene expression, including Emr1, CD68, and CD163. CONCLUSIONS: Our data suggest that dietary high fructose may potentiate chronic alcohol consumption-induced liver injury. The underlying mechanism might be due to the synergistic effect of dietary high fructose and alcohol on the activation of the TLR4 signaling pathway, which in turn leads to KC activation and phenotype switch toward M1 polarization. This study suggests that alcohol-fructose combination contributes to ALD progression.

Green Tea Polyphenols and Sulfasalazine have Parallel Anti-Inflammatory Properties in Colitis Models.

BACKGROUND: There is no cure for autoimmune chronic inflammatory bowel disease (IBD). IBD patients commonly use complementary and alternative medications of which the safety, efficacy, and interaction with standard-of-care therapies are not fully known. Thus the consequences can become life-threatening. Sulfasalazine commonly used in IBD, potentially has severe adverse effects, including infertility, pulmonary fibrosis, lack of response, and ultimately patients may require intestinal resection. We hypothesized that green tea polyphenols (GrTP, EGCG) and sulfasalazine have similar anti-inflammatory properties. METHODS: BALB/c mice received Dextran sodium sulfate (DSS) to induce colitis (ulcerative colitis model). Exposure of IL-10 deficient mice (BALB/c-background) to normal microbiota provoked enterocolitis (mimics Crohn's disease). Animals were treated with agents incorporated into daily diets. Control animals received sham treatment. RESULTS: DSS-treated animals developed severe bloody diarrhea and colitis (score 0-4, 3.2 ± 0.27). IL-10 deficient mice developed severe enterocolitis as manifested by diarrhea, rectal prolapse, and colonic lesions. Animals tolerated regimens (GrTP, EGCG, sulfasalazine) with no major side effects, and further developed less severe colitis. IL-10 deficient animals became moribund on high dose, while tolerated low and Mid doses with significant improved symptoms of enterocolitis. GrTP, EGCG, and sulfasalazine significantly ameliorated colonic damage and histological scores in treated animals in a similar manner (GrTP vs. DSS p < 0.05; EGCG, sulfasalazine vs. DSS p < 0.01). The inflammatory markers TNFα (3-fold), IL-6 (14-fold), and serum amyloid A (40-fold) increased in colitic animals and significantly decreased with treatment regiments. In contrast, circulatory leptin levels decreased in colitic animals (twofold). EGCG additionally reduced leptin levels (p < 0.01) while GrTP and sulfasalazine had no effect on leptin levels (p < 0.05). Hepatic and colonic antioxidants were significantly depleted in colitic animals and treatment regiments significantly restored antioxidants levels. CONCLUSION: GrTP and EGCG improved antioxidants levels and attenuated severity of colitis analogous to sulfasalazine. Future studies will reveal whether polyphenols can become an alternative/additive therapy for IBD therapy in humans.

Modest fructose beverage intake causes liver injury and fat accumulation in marginal copper deficient rats.

OBJECTIVE: Dietary fructose and copper interaction may play an important role in the pathogenesis of nonalcoholic fatty liver disease. In this study, whether or not modest fructose consumption (3% fructose, w/v) (which is more closely related to the American lifestyle with regard to sugar beverage consumption) affects copper status, and causes liver injury and fat accumulation in marginal copper deficient rats was investigated. DESIGN AND METHODS: Male weanling Sprague-Dawley rats were fed either an adequate copper (6 ppm) or a marginally copper deficient (1.6 ppm) diet for 4 weeks. Deionized water or deionized water containing 3% fructose (w/v) was given ad lib. RESULTS: Modest fructose consumption further impaired copper status in the marginal copper deficient rats and increased hepatic iron accumulation. Liver injury and fat accumulation were significantly induced in the marginal copper deficient rats exposed to fructose. CONCLUSIONS: Our data suggest that modest fructose consumption can impair copper status and lead to hepatic iron overload, which in turn, may lead to liver injury and fatty liver in marginal copper deficient rats. This study provides important information on dietary fructose and copper interaction, suggesting that dietary fructose-induced low copper availability might be an important mechanism underlying fructose-induced fatty liver.

p-Aminophenol-induced cytotoxicity in Jurkat T cells: protective effect of 2(RS)-n-propylthiazolidine-4(R)-carboxylic acid.

Acetaminophen (APAP) is hepatotoxic and can cause toxicity in Jurkat T cells. p-Aminophenol (PAP), an industrial chemical and APAP metabolite, is nephrotoxic and hepatotoxic. Its potential toxicity in Jurkat T cells was investigated. PAP (10-250 µM) caused toxicity (decreased survival and increased LDH activity in incubation medium) and GSH depletion. At a concentration of 100 µM but not 250 µM, PAP increased DNA fragmentation. It decreased p-Akt levels (Elisa) and at higher concentrations decreased p-Akt expression (Western blotting). It had no effect on FasL expression. The cysteine precursor 2(RS)-n-propylthiazolidine-4(R)-carboxylic acid (250 µM) attenuated the PAP (100 µM)-induced decrease in viability and prevented GSH depletion and increased DNA fragmentation. It attenuated the PAP-induced decrease in p-Akt levels and protected against the decrease in p-Akt expression. The results demonstrate PAP-induced toxicity and suggest that it is due at least in part to apoptosis and involves GSH depletion and p-Akt inactivation.

Copper deficiency exacerbates bile duct ligation-induced liver injury and fibrosis in rats.

Copper levels are elevated in a variety of liver fibrosis conditions. Lowering copper to a certain level protects against fibrosis. However, whether severe copper deficiency is protective against liver fibrosis is not known. The purpose of the present study is to evaluate this question by inducing severe copper deficiency using the copper chelator, tetrathiomolybdate (TM), in a bile duct ligation (BDL) rat model. Male Sprague-Dawley rats were divided into four groups: sham, sham plus TM, BDL, and BDL plus TM. TM was given in a daily dose of 10 mg/kg by body weight by means of intragastric gavage, beginning 5 days after BDL. All animals were killed 2 weeks after surgery. Severe copper deficiency was induced by TM overdose in either sham or BDL rats, as shown by decreased plasma ceruloplasmin activity. Liver injury and fibrosis were exacerbated in BDL rats with TM treatment, as illustrated by robustly increased plasma aspartate aminotransferase and hepatic collagen accumulation. Iron stores, as measured by plasma ferritin, were significantly increased in copper-deficient BDL rats. Moreover, hepatic heme oxygenase-1 expression was markedly down-regulated by copper deficiency in BDL rats. In addition, hepatic gene expression involving mitochondrial biogenesis and ß-oxidation was significantly up-regulated in BDL rats, and this increase was abolished by copper deficiency. In summary, severe copper deficiency exacerbates BDL-induced liver injury and liver fibrosis, probably caused by increased iron overload and decreased antioxidant defenses and mitochondrial dysfunction.

Ethanol exposure modulates hepatic S-adenosylmethionine and S-adenosylhomocysteine levels in the isolated perfused rat liver through changes in the redox state of the NADH/NAD(+) system.

Methionine metabolism is disrupted in patients with alcoholic liver disease, resulting in altered hepatic concentrations of S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), and other metabolites. The present study tested the hypothesis that reductive stress mediates the effects of ethanol on liver methionine metabolism. Isolated rat livers were perfused with ethanol or propanol to induce a reductive stress by increasing the NADH/NAD(+) ratio, and the concentrations of SAM and SAH in the liver tissue were determined by high-performance liquid chromatography. The increase in the NADH/NAD(+) ratio induced by ethanol or propanol was associated with a marked decrease in SAM and an increase in SAH liver content. 4-Methylpyrazole, an inhibitor the NAD(+)-dependent enzyme alcohol dehydrogenase, blocked the increase in the NADH/NAD(+) ratio and prevented the alterations in SAM and SAH. Similarly, co-infusion of pyruvate, which is metabolized by the NADH-dependent enzyme lactate dehydrogenase, restored the NADH/NAD(+) ratio and normalized SAM and SAH levels. The data establish an initial link between the effects of ethanol on the NADH/NAD(+) redox couple and the effects of ethanol on methionine metabolism in the liver.

Multi-laboratory validation of very high sun protection factor values.

BACKGROUND: High sun protection factor (SPF) sunscreens have multiple benefits but there has not been validation of the test method for determining SPF values higher than 50. This study addresses specifically the accuracy and reproducibility of the high SPF test. METHODS: Two high SPF formulations with a standard reference (SPF 15) were tested at four independent test facilities according to the 2007 FDA proposed amendments to the sunscreen monograph. Statistical analysis was performed to compare the SPF results within each lab as well as the SPF results between different labs. RESULTS: The test formulations have overall mean values of 90.5 and 70.7. There was no statistically significant difference between the labs for either formulation and all four labs were able to statistically differentiate these two levels of SPF values. The coefficients of variance (CV) for the high SPF formulations were comparable to those of the corresponding SPF 15 reference within each lab. CONCLUSIONS: The data show that SPF values above 50 and up to at least 90 can be measured by multiple laboratories with accuracy and reproducibility.

A model for chronic mucosal inflammation in IBD and periodontitis.

BACKGROUND: Chronic inflammation of mucosal surfaces is an aberrant immune response to luminal bacteria and generates an array of oxygen radicals leading to tissue destruction and loss of function, as noted in IBD and periodontitis. We hypothesized that mucosal injury after "oral delivery" of dextran sulfate sodium (DSS) or TNBS for an extended period of 18 weeks is reflected by chronic inflammatory responses in a time-dependent fashion. METHODS: Dextran sulfate sodium was administered in the diet biweekly; TNBS or sham controls was administered orally twice a week. Additional groups received TNBS or sham injections into gingival tissue. RESULTS: Animals tolerated oral applications with no severe clinical symptoms. The DSS-group developed diarrhea during the period of administration, and returned to normal during DSS abstinence. The TNBS-group developed no systemic clinical symptoms. Splenic length and weight increased in the DSS-group in a time-dependent fashion (P < 0.01) and remained normal in the TNBS-group. Colons from the DSS-group were significantly shortened (P < 0.001) and colonic weight increased compared with controls or the TNBS-group (P < 0.05). The DSS-group developed extensive dilation of the stomach wall, ileum, and megacolon, with abdominal fat deposits. In addition, the DSS-group showed dysregulated hepatic concentrations of antioxidants (i.e. cysteine, GSH, SAMe) in a time-dependent manner that correlated with a significance increase in alveolar bone resorption. Localized TNBS-mucosal delivery caused severe inflammation, granuloma formation, and rapid bone resorption. CONCLUSIONS: This model of mucosal stimulation eliciting chronic inflammatory responses in the gut and oral cavity mimics aspects of IBD and periodontal disease progression in patients.

Betaine for nonalcoholic fatty liver disease: results of a randomized placebo-controlled trial.

UNLABELLED: Based on animal studies and pilot studies in humans, betaine, a methyl donor for the remethylation of homocysteine, may be a therapeutic agent for nonalcoholic steatohepatitis (NASH). We evaluated the safety and efficacy of betaine for patients with NASH and whether betaine positively modified factors postulated to be "second hits" and underlying mechanisms of NASH. We conducted a randomized placebo-control study of 55 patients with biopsy-proven NASH who received either oral betaine (20 g daily) or placebo for 12 months. Pre- and posttreatment variables were analyzed using the paired t test or Wilcoxon rank test. Treatment groups were comparable at baseline. Of the 35 patients (17 betaine, 18 placebo) who completed the study, 34 patients (16 betaine, 18 placebo) underwent posttreatment liver biopsy. Patients randomized to betaine had a decrease in steatosis grade. No intra- or intergroup differences or changes in nonalcoholic fatty liver disease activity score or fibrosis stage were noted. Elevations of insulin, glucose, and proinflammatory cytokines and the reduced antioxidant status noted in NASH patients did not improve with betaine therapy. The antiinflammatory agent adiponectin was significantly reduced in both groups and did not change with therapy. Lastly, S-adenosylhomocysteine was approximately twice normal and was not reduced by betaine therapy. CONCLUSION: Compared to placebo, betaine did not improve hepatic steatosis but may protect against worseningsteatosis [corrected]. High-dose betaine supplementation failed to reduce S-adenosylhomocysteine and did not positively affect any of the second hit mechanisms postulated to contribute to NASH that we studied. Although betaine has been proven effective in treating hepatic steatosis in several animal models, translating novel therapeutic options noted in animal studies to humans with NASH will prove challenging.

Nutrition intervention: a strategy against systemic inflammatory syndrome.

BACKGROUND: Sepsis and septic shock syndrome are the leading causes of death in critically ill patients. Lipopolysaccharide (LPS) released by the colonic microorganisms may translocate across a compromised lumen, leading to upregulated reactive oxidative stress, inflammation, and sepsis. The authors examined an enteral formula high in cysteine (antioxidant precursor), omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and prebiotic fructooligosaccharides (FOS) against systemic inflammatory syndrome. METHODS: Rats were allocated to (1) standard soy-based diet high in cysteine and crude fiber and devoid of EPA-DHA (CHOW); (2) whey-peptide-based liquid diet high in cysteine, EPA-DHA, and FOS (CYSPUFA); or (3) casein-based liquid isonitrogenous diet, low in cysteine and devoid of EPA-DHA-FOS (CASN). Liquid diets provided 25% and CHOW, 23% of calories as protein. After 6 days on diets, rats received an intraperitoneal injection of LPS or saline. Animals gained weight on their respective diets and lost weight after LPS administration. The CYSPUFA group lost considerably less weight (vs CASN or CHOW, P < .05). Inflammatory cytokines significantly increased by 4 hours and subsided 18 hours after assault. The CASN group showed elevated liver enzyme alanine aminotransferase release from damaged hepatocytes and developed severe hepatic pathology with low hematocrit. The CHOW group developed more severe hepatic lesions compared with those on liquid diets. Concentration of liver enzyme and pathology were improved in rats receiving CYSPUFA. CONCLUSIONS: Data indicate that CYSPUFA, a diet rich in EPA-DHA-FOS, protects against LPS-induced systemic inflammatory responses and warrants clinical studies in critically ill patients.

Inhibition of methionine adenosyltransferase II induces FasL expression, Fas-DISC formation and caspase-8-dependent apoptotic death in T leukemic cells.

Methionine adenosyltransferase II (MAT II) is a key enzyme in cellular metabolism and catalyzes the formation of S-adenosylmethionine (SAMe) from L-methionine and ATP. Normal resting T lymphocytes have minimal MAT II activity, whereas activated proliferating T lymphocytes and transformed T leukemic cells show significantly enhanced MAT II activity. This work was carried out to examine the role of MAT II activity and SAMe biosynthesis in the survival of leukemic T cells. Inhibition of MAT II and the resultant decrease in SAMe levels enhanced expression of FasL mRNA and protein, and induced DISC (Death Inducing Signaling Complex) formation with FADD (Fas-associated Death Domain) and procaspase-8 recruitment, as well as concomitant increase in caspase-8 activation and decrease in c-FLIP(s) levels. Fas-initiated signaling induced by MAT II inhibition was observed to link to the mitochondrial pathway via Bid cleavage and to ultimately lead to increased caspase-3 activation and DNA fragmentation in these cells. Furthermore, blocking MAT 2A mRNA expression, which encodes the catalytic subunits of MAT II, using a small-interfering RNA approach enhanced FasL expression and cell death, validating the essential nature of MAT II activity in the survival of T leukemic cells.

Clinical profile of young children with mental retardation and developmental delay in Hong Kong.

OBJECTIVE: To report the clinical profile of children with mental retardation and developmental delay diagnosed by the Child Assessment Service. DESIGN: Retrospective study. SETTING: Child Assessment Service, Department of Health, Hong Kong. PARTICIPANTS: Data pertaining to the children with mental retardation and developmental delay were drawn from an in-house clinical information system in the year 2004. MAIN OUTCOME MEASURES: Clinical profiles including: sources, reasons and age of referral, diagnosis, gender ratio, co-morbidities, and socio-economic background. RESULTS: In 2004, 23% (1463 of 6439) of Child Assessment Service referrals were diagnosed to have mental retardation or developmental delay. The Family Health Service was the major source of referral (64%). The majority (93%) of children were referred before the age of 6 years. The most common reason for referral was language delay (39%). More boys were affected (3 boys: 1 girl). The two most common co-morbidities were autistic spectrum disorders (33% in mental retardation and 19% in developmental delay) and discrepant language delay (17% in mental retardation and 47% in developmental delay). The socio-economic status of these families was higher than those in the general population. CONCLUSION: The data presented here provide information on the descriptive epidemiology of mental retardation and developmental delay among Hong Kong children. Since mental retardation and developmental delay are common developmental disabilities in Hong Kong, public health education to promote and ensure early screening and identification of cases is an important prelude to early training and guidance for families with children having these conditions.

Green-tea polyphenols downregulate cyclooxygenase and Bcl-2 activity in acetaminophen-induced hepatotoxicity.

Acetaminophen (APAP) elicits hepatotoxicity via multifactorial pathways, including increased apoptosis, cyclooxygenase (Cox-2) generation, reactive metabolite release, and glutathione (GSH) depletion. We previously showed that mice that consumed different antioxidants in their diets were protected against APAP-induced hepatotoxicity. We therefore further investigated the mechanisms by which green-tea polyphenols (GrTP) protect against APAP-induced hepatic damage. Mice were administered a diet supplemented with GrTP or vehicle for 5 consecutive days followed by intraperitoneal (IP) injection of a toxic dose of APAP or sham. APAP administration upregulated Cox-2 and B-cell lymphoma-2 (Bcl-2) production and had an effect, albeit minor, on Cox-1 and Fas expression in hepatic tissue. GrTP supplementation normalized APAP induced Cox-2 expression and Bcl-2 activation (P < 0.01), as evidenced by immunohistochemistry and Western blot analyses. Similarly, APAP administration elicited marked depletion (99%) in hepatic reduced GSH (rGSH) and endogenous S-adenosylmethionine (SAMe) concentrations (twofold) when compared with sham. APAP also caused severe centrilobular apoptosis and necrosis accompanied by leukocyte infiltration and marked elevations in the hepatic enzyme, alanine aminotransferase (ALT) released from damaged hepatocytes, and cytokine tumor necrosis factor alpha (TNF-alpha). GrTP improved hepatic histopathology (P < 0.01) and attenuated ALT activity (P < 0.05) and the depletion of rGSH (P < 0.05). In conclusion, GrTP supplementation attenuated hepatotoxicity by normalizing Cox-2 and Bcl-2 activation, suggesting a potential use for GrTP in treatng APAP toxicity.

Tetrathiomolybdate protects against bile duct ligation-induced cholestatic liver injury and fibrosis.

Tetrathiomolybdate (TM), a potent copper-chelating drug, was initially developed for the treatment of Wilson's disease. Our working hypothesis is that the fibrotic pathway is copper-dependent. Because biliary excretion is the major pathway for copper elimination, a bile duct ligation (BDL) mouse model was used to test the potential protective effects of TM. TM was given in a daily dose of 0.9 mg/mouse by means of intragastric gavage 5 days before BDL. All the animals were killed 5 days after surgery. Plasma liver enzymes and total bilirubin were markedly decreased in TM-treated BDL mice. TM also inhibited the increase in plasma levels of tumor necrosis factor (TNF)-alpha and transforming growth factor (TGF)-beta1 seen in BDL mice. Cholestatic liver injury was markedly attenuated by TM treatment as shown by histology. Hepatic collagen deposition was significantly decreased, and it was paralleled by a significant suppression of hepatic smooth muscle alpha-actin and fibrogenic gene expression in TM-treated BDL mice. Although the endogenous antioxidant ability was enhanced, oxidative stress as shown by malondialdehyde and 4-hydroxyalkenals, hepatic glutathione/oxidized glutathione ratio, was not attenuated by TM treatment, suggesting the protective mechanism of TM may be independent of oxidative stress. In summary, TM attenuated BDL-induced cholestatic liver injury and fibrosis in mice, in part by inhibiting TNF-alpha and TGF-beta1 secretion. The protective mechanism seems to be independent of oxidative stress. Our data provide further evidence that TM might be a potential therapy for hepatic fibrosis.

Inhibition of adiponectin production by homocysteine: a potential mechanism for alcoholic liver disease.

UNLABELLED: Although recent evidence suggests that down-regulation of production of the adipocyte hormone adiponectin has pathophysiological consequences for the development of alcoholic liver disease (ALD), the underlying mechanisms are elusive. Abnormal hepatic methionine-homocysteine metabolism induced by prolonged alcohol exposure has been reported both in clinical and experimental studies of ALD. Here, we conducted both in vivo and in vitro experiments to examine the effects of prolonged alcohol exposure on homocysteine levels in adipose tissue, its potential involvement in regulating adiponectin production, and the consequences for ALD. Chronic alcohol exposure decreased the circulating adiponectin concentration and adiponectin messenger RNA (mRNA) and protein levels in epididymal fat pads. Alcohol feeding induced modest hyperhomocysteinemia and increased homocysteine levels in the epididymal fat pad, which was associated with decreased mRNA levels of cystationine beta-synthase. Betaine supplementation (1.5%, wt/vol) in the alcohol-fed mice reduced homocysteine accumulation in adipose tissue and improved adiponectin levels. Moreover, exogenous homocysteine administration reduced gene expression, protein levels, and secretion of adiponectin in primary adipocytes. Furthermore, rats fed a high-methionine diet (2%, wt/wt) were hyperhomocysteinemic and had decreased adiponectin levels in both plasma and adipose tissue, which was associated with suppressed AMP-activated protein kinase activation in the liver. Mechanistic studies revealed that both inactivation of the extracellular signal regulated kinase 1/2 pathway and induction of endoplasmic reticulum stress response, specifically C/EBP homologous protein expression, may contribute to the inhibitory effect exerted by homocysteine. CONCLUSION: Chronic alcohol feeding caused abnormal accumulation of homocysteine in adipocytes, which contributes to decreased adiponectin production in ALD.

Methionine deficiency and hepatic injury in a dietary steatohepatitis model.

Methionine (Meth) is an essential amino acid involved in DNA methylation and glutathione biosynthesis. We examined the effect of Meth on the development of steatohepatitis. Rats were fed (five weeks) amino acid-based Meth-choline-sufficient (A-MCS) or total deficient (MCD) diets and gavaged daily (two weeks) with vehicle (B-vehicle/MCD), or Meth replacement (C-Meth/MCD). To assess the effect of short-term deficiency, after three weeks one MCS group was fed a deficient diet (D-MCS/MCD). Animals fed the deficient diet for two weeks lost (29%) weight and after five weeks weighed one third as much as those on the sufficient diet, and also developed anemia (P < 0.01). Hepatic transaminases progressively increased from two to five weeks (P < 0.01), leading to severe hepatic pathology. Meth administration normalized hematocrit, improved weight (P < 0.05), and suppressed abnormal enzymes activities (P < 0.01). Meth administration improved blood and hepatic glutathione (GSH), S-adenosylmethionine (SAMe), and hepatic lesions (P < 0.01). The deficient diet significantly upregulated proinflammatory and fibrotic genes, which was ameliorated by Meth administration. These data support a pivotal role for methionine in the pathogenesis of the dietary model of Meth-choline-deficient (MCD) steatohepatitis (NASH).

Effects of 2(RS)-n-propylthiazolidine-4(R)-carboxylic acid on 4-hydroxy-2-nonenal-induced apoptotic T cell death.

4-Hydroxy-2-nonenal (HNE), the aldehydic product of lipid peroxidation, is associated with multiple immune dysfunctions, such as HIV and hepatitis C virus infection. HNE-induced immunosuppression could be due to a decrease in CD4+ T lymphocyte activation or proliferation. Glutathione (GSH) is the most abundant endogenous antioxidant in cells, and an adduct between HNE and GSH has been suggested to be a marker of oxidative stress. Our earlier studies showed that HNE induced cytotoxicity and Akt inactivation, which led to the enhancement of FasL expression and concomitantly decreased cellular FLICE-like inhibitory protein (c-FLIP(S)) levels. In this study, we found that HNE caused intracellular GSH depletion in Jurkat T cells, and we further investigated the role of 2(RS)-n-propylthiazolidine-4(R)-carboxylic acid (PTCA), a GSH prodrug, in attenuating HNE-induced cytotoxicity in CD4+ T lymphocytes. The results show that PTCA protected against HNE-induced apoptosis and depletion of intracellular GSH. PTCA also suppressed FasL expression through increasing levels of Akt kinase as well as antiapoptotic c-FLIP(S) and decreasing the activation of type 2 protein serine/threonine phosphatase. Taken together, these data demonstrate a novel correlation between GSH levels and Akt activation in T lymphocyte survival, which involves FasL down-regulation and c-FLIP(S) expression through increasing intracellular GSH levels. This suggests that PTCA could potentially be used in the treatment of oxidative stress-induced immunosuppressive diseases.

Ethanol inhibits methionine adenosyltransferase II activity and S-adenosylmethionine biosynthesis and enhances caspase-3-dependent cell death in T lymphocytes: relevance to alcohol-induced immunosuppression.

An important aspect in alcohol abuse-associated immune suppression is the loss of T helper CD4(+) lymphocytes, leading to impairment of multiple immune functions. Our work has shown that ethanol can sensitize CD4(+) T lymphocytes to caspase-3-dependent activation-induced cell death (AICD). It has been demonstrated that the formation of S-adenosylmethionine (SAMe) catalyzed by methionine adenosyltransferase (MAT) II is essential for CD4(+) T-cell activation and proliferation. Since ethanol is known to affect SAMe metabolism in hepatocytes, we investigated the effect of ethanol on MAT II activity/expression, SAMe biosynthesis and cell survival in CD4(+) T lymphocytes. We demonstrate for the first time that ethanol at a physiologically relevant concentration (25 mM) substantially decreased the enzymatic activity of MAT II in T lymphocytes. Ethanol was observed to decrease the transcription of MAT2A, which encodes the catalytic subunit of MAT II and is vital for MAT II activity and SAMe biosynthesis. Furthermore, correspondent to its effect on MAT II, ethanol decreased intracellular SAMe levels and enhanced caspase-3-dependent AICD. Importantly, restoration of intracellular SAMe levels by exogenous SAMe supplementation considerably decreased both caspase-3 activity and apoptotic death in T lymphocytes. In conclusion, our data show that MAT II and SAMe are critical molecular components essential for CD4(+) T-cell survival that are affected by ethanol, leading to enhanced AICD. Furthermore, these studies provide a clinical paradigm for the development of much needed therapy using SAMe supplementation in the treatment of immune dysfunction induced by alcohol abuse.