Alteration of intestinal intraepithelial lymphocytes and increased bacterial translocation in a murine model of cirrhosis

Effects of elafibranor on liver fibrosis and gut barrier function in a mouse model of alcohol-associated liver disease

BACKGROUND

Alcohol-associated liver disease (ALD) is a leading cause of liver-related morbidity and mortality, but there are no therapeutic targets and modalities to prevent ALD-related liver fibrosis. Peroxisome proliferator activated receptor (PPAR) α and δ play a key role in lipid metabolism and intestinal barrier homeostasis, which are major contributors to the pathological progression of ALD. Meanwhile, elafibranor (EFN), which is a dual PPARα and PPARδ agonist, has reached a phase III clinical trial for the treatment of metabolic dysfunction-associated steatotic liver disease and primary biliary cholangitis. However, the benefits of EFN for ALD treatment is unknown.

AIM

To evaluate the inhibitory effects of EFN on liver fibrosis and gut-intestinal barrier dysfunction in an ALD mouse model.

METHODS

ALD-related liver fibrosis was induced in female C57BL/6J mice by feeding a 2.5% ethanol (EtOH)-containing Lieber-DeCarli liquid diet and intraperitoneally injecting carbon tetrachloride thrice weekly (1 mL/kg) for 8 weeks. EFN (3 and 10 mg/kg/day) was orally administered during the experimental period. Histological and molecular analyses were performed to assess the effect of EFN on steatohepatitis, fibrosis, and intestinal barrier integrity. The EFN effects on HepG2 lipotoxicity and Caco-2 barrier function were evaluated by cell-based assays.

RESULTS

The hepatic steatosis, apoptosis, and fibrosis in the ALD mice model were significantly attenuated by EFN treatment. EFN promoted lipolysis and β-oxidation and enhanced autophagic and antioxidant capacities in EtOH-stimulated HepG2 cells, primarily through PPARα activation. Moreover, EFN inhibited the Kupffer cell-mediated inflammatory response, with blunted hepatic exposure to lipopolysaccharide (LPS) and toll like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) signaling. EFN improved intestinal hyperpermeability by restoring tight junction proteins and autophagy and by inhibiting apoptosis and proinflammatory responses. The protective effect on intestinal barrier function in the EtOH-stimulated Caco-2 cells was predominantly mediated by PPARδ activation.

CONCLUSION

EFN reduced ALD-related fibrosis by inhibiting lipid accumulation and apoptosis, enhancing hepatocyte autophagic and antioxidant capacities, and suppressing LPS/TLR4/NF-κB-mediated inflammatory responses by restoring intestinal barrier function.

Gut-liver axis: Recent concepts in pathophysiology in alcohol-associated liver disease

The growing recognition of the role of the gut microbiome's impact on alcohol-associated diseases, especially in alcohol-associated liver disease, emphasizes the need to understand molecular mechanisms involved in governing organ-organ communication to identify novel avenues to combat alcohol-associated diseases. The gut-liver axis refers to the bidirectional communication and interaction between the gut and the liver. Intestinal microbiota plays a pivotal role in maintaining homeostasis within the gut-liver axis, and this axis plays a significant role in alcohol-associated liver disease. The intricate communication between intestine and liver involves communication between multiple cellular components in each organ that enable them to carry out their physiological functions. In this review, we focus on novel approaches to understanding how chronic alcohol exposure impacts the microbiome and individual cells within the liver and intestine, as well as the impact of ethanol on the molecular machinery required for intraorgan and interorgan communication.

Cirrhosis-associated immune dysfunction

The term cirrhosis-associated immune dysfunction (CAID) comprises the distinctive spectrum of immune alterations associated with the course of end-stage liver disease. Systemic inflammation and immune deficiency are the key components of CAID. Their severity is highly dynamic and progressive, paralleling cirrhosis stage. CAID involves two different immune phenotypes: the low-grade systemic inflammatory phenotype and the high-grade systemic inflammatory phenotype. The low-grade systemic inflammatory phenotype can be found in patients with compensated disease or clinical decompensation with no organ failure. In this phenotype, there is an exaggerated immune activation but the effector response is not markedly compromised. The high-grade systemic inflammatory phenotype is present in patients with acute-on-chronic liver failure, a clinical situation characterized by decompensation, organ failure and high short-term mortality. Along with high-grade inflammation, this CAID phenotype includes intense immune paralysis that critically increases the risk of infections and worsens prognosis. The intensity of CAID has important consequences on cirrhosis progression and correlates with the severity of liver insufficiency, bacterial translocation and organ failure. Therapies targeting the modulation of the dysfunctional immune response are currently being evaluated in preclinical and clinical studies.

Gut Microbiota and Liver Interaction through Immune System Cross-Talk: A Comprehensive Review at the Time of the SARS-CoV-2 Pandemic

Background and aims: The gut microbiota is a complex ecosystem containing bacteria, viruses, fungi, yeasts and other single-celled organisms. It is involved in the development and maintenance of both innate and systemic immunity of the body. Emerging evidence has shown its role in liver diseases through the immune system cross-talk. We review herein literature data regarding the triangular interaction between gut microbiota, immune system and liver in health and disease. Methods: We conducted a search on the main medical databases for original articles, reviews, meta-analyses, randomized clinical trials and case series using the following keywords and acronyms and their associations: gut microbiota, microbiome, gut virome, immunity, gastrointestinal-associated lymphoid tissue (GALT), non-alcoholic fatty liver disease (NAFLD), non-alcoholic steato-hepatitis (NASH), alcoholic liver disease, liver cirrhosis, hepatocellular carcinoma. Results: The gut microbiota consists of microorganisms that educate our systemic immunity through GALT and non-GALT interactions. The latter maintain health but are also involved in the pathophysiology and in the outcome of several liver diseases, particularly those with metabolic, toxic or immune-mediated etiology. In this context, gut virome has an emerging role in liver diseases and needs to be further investigated, especially due to the link reported between severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection and hepatic dysfunctions. Conclusions: Changes in gut microbiota composition and alterations in the immune system response are involved in the pathogenesis of metabolic and immune-mediated liver diseases.

Probiotic mixture VSL#3: An overview of basic and clinical studies in chronic diseases

Probiotics are known as “live microorganisms” and have been proven to have a health effect on hosts at the proper dose. Recently, a kind of probiotic mixture including eight live bacterial strains, VSL#3, has attracted considerable attention for its combined effect. VSL#3 is the only probiotic considered as a kind of medical food; it mainly participates in the regulation of the intestinal barrier function, including improving tight junction protein function, balancing intestinal microbial composition, regulating immune-related cytokine expression and so on. The objective of this review is to discuss the treatment action and mechanism for the administration of VSL#3 in chronic diseases of animals and humans (including children). We found that VSL#3 has a therapeutic or preventive effect in various systemic diseases per a large number of studies, including digestive systemic diseases (gastrointestinal diseases and hepatic diseases), obesity and diabetes, allergic diseases, nervous systemic diseases, atherosclerosis, bone diseases, and female reproductive systemic diseases.

[Liver diseases: The pathogenetic role of the gut microbiome and the potential of treatment for its modulation]

The paper gives an update on the role of the gut microbiome (GM) in the development of nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, alcoholic liver disease, liver cirrhosis (LC), and its complications, such as hepatic encephalopathy (HE) and hepatocellular carcinoma (HCC), and discusses the possibilities of its correction with prebiotics, probiotics, synbiotics, antibiotics, and fecal microbiota transplantation (FMT). The pathophysiology of the liver diseases in question demonstrates some common features that are characterized by pathogenic changes in the composition of the gastrointestinal tract microflora, by intestinal barrier impairments, by development of endotoxemia, by increased liver expression of proinflammatory factors, and by development of liver inflammation. In progressive liver disease, the above changes are more pronounced, which contributes to the development of LC, HE, and HCC. GM modulation using prebiotics, probiotics, synbiotics, antibiotics, and FMT diminishes dysbacteriosis, strengthens the intestinal mucosal barrier, reduces endotoxemia and liver damage, and positively affects the clinical manifestations of HE. Further investigations are needed, especially in humans, firstly, to assess a relationship of GM to the development of liver diseases in more detail and, secondly, to obtain evidence indicating the therapeutic efficacy of GM-modulating agents in large-scale, well-designed, randomized, controlled, multicenter studies.

Protective effect of Periplaneta americana extract in ulcerative colitis rats induced by dinitrochlorobenzene and acetic acid

CONTEXT

Periplaneta americana L. (Dictyoptera; Blattaria) has been traditional used to treat ulcers, burns and heart disease in southwestern China. Recent reports indicate that P. americana can be used as an alternative medicine in therapy of ulcerative colitis, but the mechanism involved remains obscure.

OBJECTIVE

This study investigated the therapeutic effect of P. americana extract (PAE) in rat colitis and elucidated its potential mechanism.

MATERIALS AND METHODS

Dinitrochlorobenzene and acetic acid-induced colitis rat model was applied. Colitis rats were treated with PAE for 10 d and estimated disease activity index daily. Rectal inflammation was assessed by myeloperoxidase activity and histological changes. Another colitis rats were treated with PAE for 4 d, meanwhile gavage with Escherichia coli labelled with green fluorescent protein. Mesenteric lymph nodes, colon, liver, spleen and kidney were harvested for bacteria culture. PAE was suspended in distilled water then partitioned with ethyl acetate and n-butanol to obtain ethyl acetate fraction, n-butanol fraction and water fraction, respectively. Fibroblasts proliferation and collagen accumulation of each fraction was determined.

RESULTS

PAE treatment reduced the severity of colitis and tissue myeloperoxidase accumulation (p < 0.001). Also, PAE at 80 mg/kg significantly inhibited labelled E. coli from translocating to distant organs, especially to MLN and liver. Additionally, PAE significantly stimulated fibroblasts proliferation (126.9%) and collagen accumulation (130.8%) for 48 h incubation. Among the partitions, ethyl acetate fraction generally had higher fibroblast viability enhanced-activity.

CONCLUSIONS

PAE can protect against ulcerative colitis and this protection is attributed to anti-inflammation and fibroblasts viability.

Microbiota, immunity and the liver

The gut harbors a complex community of over 100 trillion microbial cells known to exist in symbiotic harmony with the host influencing human physiology, metabolism, nutrition and immune function. It is now widely accepted that perturbations of this close partnership results in the pathogenesis of several major diseases with increasing evidence highlighting their role outside of the intestinal tract. The intimate proximity and circulatory loop of the liver and the gut has attracted significant attention regarding the role of the microbiota in the development and progression of liver disease. Here we give an overview of the interaction between the microbiota and the immune system and focus on their convincing role in both the propagation and treatment of liver disease.

Targeting gut-liver axis for the treatment of nonalcoholic steatohepatitis: translational and clinical evidence

Nonalcoholic fatty liver disease (NAFLD) is widely emerging as the most prevalent liver disorder and is associated with increased risk of liver-related and cardiovascular mortality. Recent experimental and clinical studies have revealed the pivotal role played by the alteration of gut-liver axis in the onset of fatty liver and related metabolic disturbances. Gut-liver cross talk is implicated not only in the impairment of lipid and glucose homeostasis leading to steatogenesis, but also in the initiation of inflammation and fibrogenesis, which characterize nonalcoholic steatohepatitis (NASH), the evolving form of NAFLD. The gut microbiota has been recognized as the key player in the gut-liver liaison and because of its complexity can act as a villain or a victim. Gut microbiota not only influences absorption and disposal of nutrients to the liver, but also conditions hepatic inflammation by supplying toll-like receptor ligands, which can stimulate liver cells to produce proinflammatory cytokines. Thus, the modification of intestinal bacterial flora by specific probiotics has been proposed as a therapeutic approach for the treatment of NASH. In this review, we summarized the evidence regarding the role of gut-liver axis in the pathogenesis of NASH and discussed the potential therapeutic role of gut microbiota modulation in the clinical setting.

Effect of Saccharomyces boulardii on endotoxemia in rats with cirrhosis

AIM: To investigate the protective effect of Saccharomyces boulardii on intestinal endotoxemia in rats with cirrhosis and the underlying mechanism.

METHODS: A rat model of cirrhosis was developed by administering 40% carbon tetrachloride and 10% ethanol in drinking water. After 12 wk, Saccharomyces boulardii formulation was intragastrically administered to rats at 75 × 10⁸ CFU/(kg•d) for 14 d. A normal control group and a model control group were given equal volume of saline. Plasma endotoxin levels were assayed. Enzyme-linked immunosorbent assay was used to detect serum tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels. An automatic biochemical analyzer was used to assay serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and albumin levels.

RESULTS: Plasma concentration of endotoxin in the model control group (0.251 EU/mL ± 0.011 EU/mL) was significantly higher than that in the treatment group (0.168 EU/mL ± 0.012 EU/mL) (P < 0.01). The concentrations of serum TNF-α and IL-6 in the model control group (2.37 ng/L ± 0.14 ng/L, 214.51 ng/L ± 14.13 ng/L) were significantly higher than those in the control group (0.64 ng/L ± 0.12 ng/L, 106.63 ng/L ± 9.49 ng/L) (P < 0.01) and in the treatment group (1.59 ng/L ± 0.13 ng/L, 176.45 ng/L ± 10.81 ng/L) (P < 0.01). The concentrations of serum ALT and AST in the model control group (133.89 U/mL ± 8.09 U/mL, 176.92 U/mL ± 10.94 U/mL) were significantly higher than those in the control group (36.73 U/mL ± 6.95 U/mL, 41.35 U/mL ± 10.07 U/mL) (P < 0.01), and the concentration of serum albumin in the model control group (14.50 g/L ± 1.21 g/L) was significantly lower than that in the control group (23.99 g/L ± 1.92 g/L). The concentrations of ALT and AST were significantly lower and that of albumin was significantly higher in the treatment group compared with the model control group (P < 0.01).

CONCLUSION: Rats with cirrhosis have endotoxemia. Saccharomyces boulardii can mitigate liver injury possibly by protecting intestinal mucosal barrier and decreasing the level of endotoxemia. Saccharomyces boulardii may be considered an adjunctive therapy for chronic liver disease.

Spontaneous bacterial peritonitis: The clinical challenge of a leaky gut and a cirrhotic liver

Spontaneous bacterial peritonitis (SBP) is a frequent, life-threatening bacterial infection in patients with liver cirrhosis and ascites. Portal hypertension leads to increased bacterial translocation from the intestine. Failure to eliminate invading pathogens due to immune defects associated with advanced liver disease on the background of genetic predisposition may result in SBP. The efficacy of antibiotic treatment and prophylaxis has declined due to the spread of multi-resistant bacteria. Patients with nosocomial SBP and with prior antibiotic treatment are at a particularly high risk for infection with resistant bacteria. Therefore, it is important to adapt empirical treatment to these risk factors and to the local resistance profile. Rifaximin, an oral, non-absorbable antibiotic, has been proposed to prevent SBP, but may be useful only in a subset of patients. Since novel antibiotic classes are lacking, we have to develop prophylactic strategies which do not induce bacterial resistance. Farnesoid X receptor agonists may be a candidate, but so far, clinical studies are not available. New diagnostic tests which can be carried out quickly at the patient’s site and provide additional prognostic information would be helpful. Furthermore, we need tools to predict antibiotic resistance in order to tailor first-line antibiotic treatment of spontaneous bacterial peritonitis to the individual patient and to reduce mortality.

Beneficial effect of an omega-6 PUFA-rich diet in non-steroidal anti-inflammatory drug-induced mucosal damage in the murine small intestine

AIM: To investigate the effect of a fat rich diet on non-steroidal anti-inflammatory drug (NSAID)-induced mucosal damage in the murine small intestine.

METHODS: C57BL6 mice were fed 4 types of diets with or without indomethacin. One group was fed standard laboratory chow. The other groups were fed a fat diet consisting of 8% w/w fat, beef tallow (rich in SFA), fish oil, (rich in omega-3 PUFA), or safflower oil (rich in omega-6 PUFA). Indomethacin (3 mg/kg) was injected intraperitoneally from day 8 to day 10. On day 11, intestines and adhesions to submucosal microvessels were examined.

RESULTS: In the indomethacin-treated groups, mucosal damage was exacerbated by diets containing beef tallow and fish oil, and was accompanied by leukocyte infiltration (P < 0.05). The mucosal damage induced by indomethacin was significantly lower in mice fed the safflower oil diet than in mice fed the beef tallow or fish oil diet (P < 0.05). Indomethacin increased monocyte and platelet migration to the intestinal mucosa, whereas safflower oil significantly decreased monocyte and platelet recruitment (P < 0.05).

CONCLUSION: A diet rich in SFA and omega-3 PUFA exacerbated NSAID-induced small intestinal damage via increased leukocyte infiltration. Importantly, a diet rich in omega-6-PUFA did not aggravate inflammation as monocyte migration was blocked.

Is there a role for probiotics in liver disease?

Intestinal microbiota plays an important role in health and disease. Alteration in its healthy homeostasis may result in the development of numerous liver disorders including complications of liver cirrhosis. On the other hand, restoration and modulation of intestinal flora through the use of probiotics is potentially an emerging therapeutic strategy. There is mounting evidence that probiotics are effective in the treatment of covert and overt hepatic encephalopathy, as well as in the prevention of recurrence of encephalopathy. The beneficial effect of probiotics also extends to liver function in cirrhosis, nonalcoholic fatty liver disease, and alcoholic liver disease. On the other hand, data associating probiotics and portal hypertension is scanty and conflicting. Probiotic therapy has also not been shown to prevent primary or secondary spontaneous bacterial peritonitis. Larger clinical studies are required before probiotics can be recommended as a treatment modality in liver diseases.

Gut microbiota and liver disease

Microbes are present in large numbers in each human being, in particularly in the gastrointestinal (GI) tract, and have long been believed to have some beneficial effects for their hosts. Till recently, however, we lacked tools for studying these organisms. Rapid technological advances in recent years have markedly improved our understanding of their role both in health and disease. Recent literature suggests that organisms in the GI tract, referred to collectively as gut microbiota, play an indispensable role in the maintenance of host's homeostasis. Alterations in the gut microbiota, that is in the nature and relative density of various constituent bacterial species, appear to have a role in pathogenesis and progression of several GI and hepatic diseases. This has also opened the vista for tinkering with gut flora in an attempt to treat or prevent such diseases. In this review, we have tried to summarize information on normal gut microbiota, laboratory techniques and animal models used to study it, and the role of its perturbations in some of the common hepatic disorders, such as non-alcoholic fatty liver disease (including obesity), non-alcoholic steatohepatitis, alcoholic liver disease, and liver cirrhosis and its complications.

Pathological bacterial translocation in cirrhosis: pathophysiology, diagnosis and clinical implications

Bacterial translocation (BT) is defined by the passage of viable indigenous bacteria from the intestinal lumen to mesenteric lymph nodes (MLNs) and other territories, and its diagnostic criteria rely on the isolation of viable bacteria in MLNs. Small intestinal overgrowth, increased intestinal permeability and immunological alterations are the main factors involved in its pathogenesis. BT is obviously difficult to identify in patients with cirrhosis, and alternative methods have been proposed instead. Bacterial DNA detection and species identification in serum or ascitic fluid has been proposed as a reliable marker of BT. Bacterial products, such as endotoxin, or bacterial DNA can translocate to extra-intestinal sites and promote an immunological response similar to that produced by viable bacteria. Therefore, pathological BT plays an important role in the pathogenesis of the complications of cirrhosis, not only in infections, but by exerting a profound inflammatory state and exacerbating the haemodynamic derangement. This may promote in turn the development of hepatorenal syndrome, hepatic encephalopathy and other portal hypertension-related complications. Therapeutic approaches for the prevention of BT in experimental and human cirrhosis are summarized. Finally, new investigations are needed to better understand the pathogenesis and consequences of translocation by viable bacteria (able to grow in culture), or non-viable BT (detection of bacterial fragments with negative culture) and open new therapeutic avenues in patients with cirrhosis.

Prevention and treatment of hepatic encephalopathy: Focusing on gut microbiota

The gut flora plays an important role in the pathogenesis of the complications of cirrhosis. Hepatic encephalopathy (HE) represents a broad continuum of neuropsychological dysfunction in patients with acute or chronic liver disease and/or porto-systemic shunting of blood flow and it manifests with progressive deterioration of the superior neurological functions. The pathophysiology of this disease is complex, as it involves overproduction and reduced metabolism of various neurotoxins, particularly ammonia. Management of HE is diversified and requires several steps: elimination of precipitating factors, removal of toxins, proper nutritional support, modulation of resident fecal flora and downregulation of systemic and gut-derived inflammation. This review will provide an overview of gut barrier function and the influence of gut-derived factors on HE, focusing on the role of gut microbiota in the pathogenesis of HE and the recent literature findings on its therapeutic manipulation.

Microbial translocation in chronic liver diseases

The intestinal microflora is not only involved in the digestion of nutrients, but also in local immunity, forming a barrier against pathogenic microorganisms. The derangement of the gut microflora may lead to microbial translocation, defined as the passage of viable microorganisms or bacterial products (i.e., LPS, lipopeptides) from the intestinal lumen to the mesenteric lymph nodes and other extraintestinal sites. The most recent evidence suggests that microbial translocation (MT) may occur not only in cirrhosis, but also in the early stage of several liver diseases, including alcoholic hepatopathy and nonalcoholic fatty liver disease. Different mechanisms, such as small intestinal bacterial overgrowth, increased permeability of intestinal mucosa, and impaired immunity, may favor MT. Furthermore, MT has been implicated in the pathogenesis of the complications of cirrhosis, which are a significant cause of morbidity and mortality in cirrhotic subjects. Therapeutic strategies aiming at modulating the gut microflora and reducing MT have focused on antibiotic-based options, such as selective intestinal decontamination, and nonantibiotic-based options, such as prokinetics and probiotics. In particular, probiotics may represent an attractive strategy, even though the promising results of experimental models and limited clinical studies need to be confirmed in larger randomized trials.

Gut microbiota dysbiosis is associated with inflammation and bacterial translocation in mice with CCl4-induced fibrosis

BACKGROUND

Gut is the major source of endogenous bacteria causing infections in advanced cirrhosis. Intestinal barrier dysfunction has been described in cirrhosis and account for an increased bacterial translocation rate.

HYPOTHESIS AND AIMS

We hypothesize that microbiota composition may be affected and change along with the induction of experimental cirrhosis, affecting the inflammatory response.

ANIMALS AND METHODS

Progressive liver damage was induced in Balb/c mice by weight-controlled oral administration of carbon tetrachloride. Laparotomies were performed at weeks 6, 10, 13 and 16 in a subgroup of treated mice (n = 6/week) and control animals (n = 4/week). Liver tissue specimens, mesenteric lymph nodes, intestinal content and blood were collected at laparotomies. Fibrosis grade, pro-fibrogenic genes expression, gut bacterial composition, bacterial translocation, host's specific butyrate-receptor GPR-43 and serum cytokine levels were measured.

RESULTS

Expression of pro-fibrogenic markers was significantly increased compared with control animals and correlated with the accumulated dose of carbon tetrachloride. Bacterial translocation episodes were less frequent in control mice than in treated animals. Gram-positive anaerobic Clostridia spp count was decreased in treated mice compared with control animals and with other gut common bacterial species, altering the aerobic/anaerobic ratio. This fact was associated with a decreased gene expression of GPR43 in neutrophils of treated mice and inversely correlated with TNF-alpha and IL-6 up-regulation in serum of treated mice along the study protocol. This pro-inflammatory scenario favoured blood bacterial translocation in treated animals, showing the highest bacterial translocation rate and aerobic/anaerobic ratio at the same weeks.

CONCLUSIONS

Gut microbiota alterations are associated with the development of an inflammatory environment, fibrosis progression and bacterial translocation in carbon tetrachloride-treated mice.

Gut microbiota and probiotics in chronic liver diseases

There is a strong relationship between liver and gut: the portal system receives blood from the gut, and intestinal blood content activates liver functions. The liver, in turn, affects intestinal functions through bile secretion into the intestinal lumen. Alterations of intestinal microbiota seem to play an important role in induction and promotion of liver damage progression, in addition to direct injury resulting from different causal agents. Bacterial overgrowth, immune dysfunction, alteration of the luminal factors, and altered intestinal permeability are all involved in the pathogenesis of complications of liver cirrhosis, such as infections, hepatic encephalopathy, spontaneous bacterial peritonitis, and renal failure. Probiotics have been suggested as a useful integrative treatment of different types of chronic liver damage, for their ability to augment intestinal barrier function and prevent bacterial translocation. This review summarizes the main literature findings about the relationships between gut microbiota and chronic liver disease, both in the pathogenesis and in the treatment by probiotics of the liver damage.

Mortality among United States Coast Guard marine inspectors: a follow up

We previously assessed mortality among U.S. Coast Guard (USCG) marine inspectors (inspectors) and Coast Guard officers who were not marine inspectors (noninspectors). Here, we extended follow-up of the cohort by 14 years, ascertaining vital status 1980-1994, calculating standardized mortality ratios (SMRs) for inspectors and noninspectors, and comparing mortality rates via directly adjusted rate ratios (RRs). Both inspectors and noninspectors had deficits for all causes of death (SMR = 75 and 61, respectively) and all malignant neoplasms (SMR = 86 and 69, respectively). Compared with noninspectors, inspectors had nonstatistically significant excesses of liver cirrhosis (SMR = 124; RR = 2.2) and chronic rheumatic heart disease (SMR = 129; RR = 2.6) and deficits of cancer of the respiratory system (SMR = 59; RR = 0.8). SMRs and RRs rose with increasing probability of exposure to chemicals for cirrhosis of the liver, all accidents and motor vehicle accidents, although they fell for all causes of death, diseases of the nervous system, diseases of the circulatory system, and cancers of the respiratory system. These results suggest that contact with chemicals during inspection of merchant vessels may be involved in the development of these diseases, although other aspects of the job, such as physical activity may account for deficits in respiratory cancers.

Functional and morphological alterations in small intestine mucosa of chronic alcoholics

BACKGROUND AND AIM

Alcohol-related diseases constitute the third largest health problem after heart disease and cancer in the world. The objective was to study the effects of chronic alcohol intake on small bowel cellular functions with focus on brush border enzymes, membrane enzymes, cellular enzymes and their relationship with structural changes in small bowel mucosa of chronic alcoholics.

METHODS

Duodenal biopsies were obtained by upper gastrointestinal endoscopy of chronic alcoholics having alcoholic liver disease (ALD) with and without cirrhosis. The biopsies were then processed for enzymatic assays to analyze the status of cellular functions. Light microscopy, transmission electron microscopy, and scanning electron microscopy were done to study the morphological alterations. Control group consisted of nonalcoholic gastroesophageal reflux disease patients reporting for routine endoscopy.

RESULTS

The experimental group consisted of ALD patients which showed significant difference (P < 0.01) in cellular functions when compared with controls. The light microscopy showed partial villous atrophy, increase in lamina propria infiltrate, and intraepithelial lymphocytes as main findings in the alcoholic group. Ultrastructural evaluation revealed changes like widened intercellular junction, distorted microvilli, increased rough endoplasmic reticulum, and increased and dilated mitochondria. The enzyme parameters correlated positively with the mucosal morphology parameters indicating a direct relationship.

CONCLUSION

The study brought out the changes in small bowel of chronic alcoholics having ALD at both cellular and subcellular levels which correlated significantly.

NOD2: a potential target for regulating liver injury

The recent discovery of bacterial receptors such as NOD2 that contribute to crosstalk between innate and adaptive immune systems in the digestive tract constitutes an important challenge in our understanding of liver injury mechanisms. The present study focuses on NOD2 functions during liver injury. NOD2, TNF-alpha and IFN-gamma mRNA were quantified using real-time PCR in liver samples from patients and mice with liver injury. We evaluated the susceptibility of concanavalin A (ConA) challenge in NOD2-deficient mice (Nod2-/-) compared to wild-type littermates. We tested the effect of muramyl dipeptide (MDP), the specific activator of NOD2, on ConA-induced liver injury in C57BL/6 mice. We studied the cellular distribution and the role of NOD2 in immune cells and hepatocytes. We demonstrated that NOD2, TNF-alpha and IFN-gamma were upregulated during liver injury in mice and humans. Nod2-/- mice were resistant to ConA-induced hepatitis compared to their wild-type littermates, through reduced IFN-gamma production by immune cells. Conversely, administration of MDP exacerbated ConA-induced liver injury. MDP was a strong inducer of IFN-gamma in freshly isolated human PBMC, splenocytes and hepatocytes. Our study supports the hypothesis that NOD2 contributes to liver injury via a regulatory mechanism affecting immune cells infiltrating the liver and hepatocytes. Taken together, our results indicate that NOD2 may represent a new therapeutic target in liver diseases.

Decreased leukocyte recruitment in the mesenteric microcirculation of rats with cirrhosis is partially restored by treatment with peginterferon: an in vivo study

BACKGROUND/AIMS

Patients with liver cirrhosis are predisposed to develop bacterial infections. An essential process in inflammatory responses is the recruitment of circulating leukocytes through the activation of adhesion molecules. Interferon-alpha2a is a cytokine reported to influence the expression of adhesion molecules. We investigated the effect of peginterferon-alpha2a (PegIFN-alpha(2a)) in vivo on the leukocyte recruitment in the mesenteric microcirculation of cirrhotic rats after lipopolysaccharide exposure.

METHODS

Leukocyte rolling, adhesion and extravasation were visualized by intravital microscopy in sham-operated and common bile duct ligated (CBDL) rats. PegIFN-alpha(2a) was administered to influence leukocyte recruitment. Endothelial P-selectin, E-selectin and ICAM-1 expression were studied by immunohistochemistry.

RESULTS

CBDL placebo rats showed significantly impaired rolling, adhesion and extravasation of leukocytes compared to Sham-operated placebo rats. Endothelial P-selectin, E-selectin and ICAM-1 expressions in CBDL placebo rats were significantly reduced compared to Sham-operated placebo rats. PegIFN-alpha(2a) 18 microg normalized number of rolling leukocytes in CBDL rats, without influencing on adhering and extravasated leukocytes. PegIFN-alpha(2a) upregulates the expression of P-selectin and E-selectin in CBDL rats, but ICAM-1 expression remained significantly lower than in Sham rats.

CONCLUSIONS

Leukocyte recruitment is significantly impaired in the mesenteric microcirculation of cirrhotic rats. This deficiency appears to result from a reduced endothelial P-selectin, E-selectin and ICAM-1 expression. Peginterferon-alpha(2a) treatment normalizes rolling of leukocytes in cirrhotic rats by upregulation of P-selectin and E-selectin expressions, but has no influence on adhesion and extravasation possibly due to the absence of effect on ICAM-1 expression.

Gut flora and bacterial translocation in chronic liver disease

Increasing evidence suggests that derangement of gut flora is of substantial clinical relevance to patients with cirrhosis. Intestinal bacterial overgrowth and increased bacterial translocation of gut flora from the intestinal lumen, in particular, predispose to an increased potential for bacterial infection in this group. Recent studies suggest that, in addition to their role in the pathogenesis of overt infective episodes and the clinical consequences of sepsis, gut flora contributes to the pro-inflammatory state of cirrhosis even in the absence of overt infection. Furthermore, manipulation of gut flora to augment the intestinal content of lactic acid-type bacteria at the expense of other gut flora species with more pathogenic potential may favourably influence liver function in cirrhotic patients. Here we review current concepts of the various inter-relationships between gut flora, bacterial translocation, bacterial infection, pro-inflammatory cytokine production and liver function in this group.

Early diagnosis of bacterial and fungal infection in chronic cholestatic hepatitis B

AIM: To investigate the early diagnostic methods of bacterial and fungal infection in patients with chronic cholestatic hepatitis B.

METHODS: One hundred and one adult in -patients with chronic hepatitis B were studied and divided into 3 groups: direct bilirubin (DBil)/total bilirubin (TBil) ≥ 0.5, without bacterial and fungal infection (group A, n = 38); DBil/TBil < 0.5, without bacterial and fungal infection (group B, n = 23); DBil/TBil ≥ 0.5, with bacterial or fungal infection (group C, n = 40). The serum biochemical index and pulse rate were analyzed.

RESULTS: Level of TBil, DBil, alkaline phosphatase (ALP) and DBil/ALP in group A increased compared with that in group B. The level of ALP in group C decreased compared with that in group A, whereas the level of TBil, DBil and DBil/ALP increased (ALP: 156 ± 43, 199 ± 68, respectively, P < 0.05; TBil: 370 ± 227, 220 ± 206, respectively, P < 0.01; DBil: 214 ± 143, 146 ± 136, respectively, P < 0.01; DBil/ALP: 1.65 ± 1.05, 0.78 ± 0.70, respectively, P < 0.001). The level of DBil and infection affected DBil/ALP. Independent of the effect of DBil, infection caused DBil/ALP to rise (P < 0.05). The pulse rate in group A decreased compared with that in group B (63.7 ± 6.4, 77.7 ± 11.4, respectively, P < 0.001), and the pulse rate in group C increased compared with that in group A (81.2 ± 12.2, 63.7 ± 6.4, respectively, P < 0.001). The equation (infection = 0.218 pusle rate 1.064 DBil/ALP -16.361), with total accuracy of 85.5%, was obtained from stepwise logistic regression. Pulse rate (≥ 80/min) and DBil/ALP (≥ 1.0) were used to screen infection. The sensitivity was 62.5% and 64.7% respectively, and the specificity was 100% and 82.8% respectively.

CONCLUSION: Bacterial and fungal infection deteriorate jaundice and increase pulse rate, decrease serum ALP and increase DBil/ALP. Pulse rate, DBil/ALP and the equation (infection = 0.218 pusle rate + 1.064 DBil/ALP-16.361) are helpful to early diagnosis of bacterial and fungal infection in patients with chronic cholestatic hepatitis B.

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