Failure of Lactobacillus spp. to prevent bacterial translocation in a rat model of experimental cirrhosis

Probiotics and their derivatives as treatments for inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic relapsing disorder that is increasing in prevalence in Western society and has been linked to the development of colorectal cancer. There remains no definitive treatment for IBD, hence recent investigations have focused on the development of new therapeutics, including probiotics, which can reduce intestinal inflammation and restore balance to the gastrointestinal microbiota. Probiotics are currently being studied in greater detail, albeit predominantly in animal models of IBD. Clinical studies have yielded promising findings and justify further investigation. Furthermore, the use of inactivated probiotics as well as the soluble products produced by these bacteria has demonstrated therapeutic potential, and may in fact be more suitable, as there is no risk of sepsis associated with their administration and they can be manufactured with greater quality control. Further research is essential to define the mechanism and source of probiotic action, and to identify more efficacious strains, while future clinical trials must focus on determining whether the bacterial and genetic profiles of IBD patients influence the effectiveness of treatment.

Probiotics and liver disease

Modulation of intestinal flora through the use of probiotics is an emerging therapeutic strategy in the management of chronic liver diseases. This article focuses on the pathophysiologic basis for using probiotics in liver disease and reviews the existing literature on the subject. The role of probiotics is examined in the following areas: a) prevention of infection, b) the hyperdynamic circulatory state of cirrhosis, c) hepatic encephalopathy, d) liver function, and e) nonalcoholic fatty liver disease.

Review article: Probiotics in gastrointestinal and liver diseases

BACKGROUND

Probiotics, defined as live micro-organisms with beneficial effects for the host, are widely applied in gastrointestinal and liver diseases.

AIM AND METHOD

To review the available evidence of clinical trials on probiotics in gastrointestinal and liver diseases, with a major focus on irritable bowel syndrome, inflammatory bowel disease, pancreatitis and chronic liver diseases.

RESULTS

Evidence for the therapeutic or preventive application of particular probiotic strains is available for antibiotic-associated diarrhoea, rota-virus-associated diarrhoea and pouchitis. Results are encouraging for irritable bowel syndrome, ulcerative colitis and for reducing side effects by Helicobacter pylori eradication therapies, but are less clear for Crohn's disease, lactose intolerance and constipation. In general, for most of these patient groups, more placebo-controlled methodologically well-designed studies that pay attention to both clinical outcome and mechanistic aspects are required. The application in liver disease and pancreatitis is promising, but more human trials have to be awaited. Possible mechanisms of probiotics include modulation of the intestinal microbiota and the immune system, but different bacterial may have different effects.

CONCLUSION

Further insight into disease entities and the functioning of probiotic strains is required to be able to select disease-specific strains, which have to be tested in well-designed placebo-controlled studies.

Oral administration of Bifidobacterium longum prevents gut-derived Pseudomonas aeruginosa sepsis in mice

AIMS

The aim of the study was to evaluate the efficacy of probiotics on gut-derived sepsis caused by Pseudomonas aeruginosa in immunocompromised mice.

METHODS AND RESULTS

After oral inoculation of P. aeruginosa, mice were treated with cyclophosphamide to induce leucopenia and translocation of the intestinal P. aeruginosa into blood, thereby producing gut-derived sepsis. In this model, administration of 1 x 10(9) CFU of Bifidobacterium longum strain BB536 for 10 days significantly (P < 0.01) increased the survival rate compared with groups of mice administered either with Bifidobacterium breve strain ATCC 15700 or excipients contained in the probiotic bacterial powder. Administration of B. longum significantly decreased viable counts of P. aeruginosa in the liver and blood compared with other groups. Culture of intestinal contents revealed a significantly lower viable count of P. aeruginosa in the jejunum of B. longum-treated mice compared with other groups of mice. Furthermore, in vitro data demonstrated that B. longum possessed apparently higher adherent activity to Caco-2 cell monolayers and significantly suppressed the adherence of P. aeruginosa to the monolayers of cells compared with other groups.

CONCLUSION

Oral administration of B. longum protects mice against gut-derived sepsis caused by P. aeruginosa, and the effect may be due to interference of P. aeruginosa adherence to intestinal epithelial cells. SIGNIFICANCE AND IMPACT OF THIS STUDY: This study demonstrated that oral administration of B. longum BB536 is effective to protect against opportunistic infection with drug-resistant bacteria such as P. aeruginosa. The results suggest that probiotics may play an important role even in the immunocompromised patients.

Probiotics and prebiotics — renaissance of a therapeutic principle

Probiotics are nonpathogenic microorganisms mostly of human origin which, when administered in adequate amounts, confer a health benefit on the host and enable to prevent or improve some diseases. Probiotics may be a natural temporary constituent of the resident intestinal microflora, but their concentration is not sufficient for therapeutic purposes. The microbiota, the intestinal epithelium, and the mucosal immune system constitute the gastrointestinal ecosystem. All three components are essential for complete functional and developmental maturity of the system. The viability of intestinal microflora (including probiotic strains) requires the availability of nutritional substrates (prebiotics), i.e. various types of fiber and oligosaccharides. Prebiotics are cleaved by microbial enzymes to numerous substances (short-chain fatty acids, aminoacids, polyamines, growth factors, vitamins and antioxidants) indispensable for metabolic and functional activities of the intestinal mucosa. The principal probiotics in use include lactobacilli, bifidobacteria, some nonpathogenic strains of Escherichia coli, and Saccharomyces boulardii. These microbiota display favourable effects which qualify them for therapeutic use. For this purpose, probiotics have to fulfill a series of requirements verifying their efficacy and safety. Experimental and clinical studies examine the prerequisites for the administration of probiotics in digestive diseases, allergic and atopic affections, as well as in some extraintestinal conditions. Future goals of probiotic application include genomic analysis, controlled postnatal colonisation of the digestive tract, the use of probiotics as carriers of peroral vaccines, and recombinant probiotics with in-situ production and targeted application of therapeutic molecules.

Spontaneous bacterial peritonitis

Spontaneous bacterial peritonitis (SBP) is the infection of ascitic fluid in the absence of any intra-abdominal, surgically treatable source of infection. Despite timely diagnosis and treatment its reported incidence in ascitic patients varies between 7-30%. Ascitic paracentesis remains the chief diagnostic procedure. Automated cell counters have the same diagnostic accuracy as the manual measurement of white cells. Lately, the use of leucocyte reagent strips (dipsticks) has emerged as a useful alternative. Examination of the fluid is not complete unless the sample is inoculated in blood culture bottles. Treatment is currently with third-generation cephalosporins or oral quinolones. Following a single episode of SBP patients should have long term antibiotic prophylaxis.

[Physiopathology of bacterial translocation and spontaneous bacterial peritonitis in cirrhosis]

The key pathogenic mechanism initiating spontaneous bacterial peritonitis (SBP) is bacterial translocation (BT), a process through which enteric bacteria cross the intestinal barrier and infect the mesenteric lymph nodes, thus entering the blood circulation and ascitic fluid. The high rate of bacterial translocation in cirrhosis is due to injury to the three pilars composing the intestinal mucosal barrier (the balance of intraluminal bacterial flora, the integrity of the intestinal epithelial barrier, and the local immune system). Blood dissemination and microbial growth in ascitic fluid resulting from SBP are a consequence of damage to the immune system in cirrhosis. Hyperproduction of proinflammatory cytokines and other vasoactive substances contributes to the arterial vasodilation and renal failure that frequently complicate the course of SBP. Even in the absence of SBP, translocation of bacteria and bacterial products from the intestinal lumen contribute to systemic inactivation of immune cells in cirrhosis.

Infection et rupture de varice œsophagienne au cours de la cirrhose

Endotoxemia and bacterial infection are frequent in patients with cirrhosis. They alter systemic and splanchnic hemodynamics, worsen coagulation disorders, impair liver function and thus may induce variceal bleeding. In variceal bleeding, bacterial infection favours failure to control bleeding, early rebleeding, and death. In patients with cirrhosis and variceal bleeding, antibiotic-prophylaxis decreases bacterial infection and the incidence of early rebleeding, and, more important, significantly decreases the death rate in these patients.

The role of probiotics in gastrointestinal surgery

PURPOSE OF REVIEW

Postoperative complications in gastrointestinal elective surgery have been described as low. In certain circumstances, however, such as those including high-risk patients, the incidence is higher. In such situations, bacteremia and infectious complications may be caused by translocation of either gastrointestinal bacteria or its toxins as the result of bacterial overgrowth, loss of intestinal epithelial integrity, or immunologic compromising of the host. Attempts should be made to reduce the impact of these factors. Probiotics, which confer to the host health benefits similar to those offered by a balanced indigenous microbiota, are thought to act through a variety of mechanisms including the competition with potential pathogens for nutrients or enterocyte adhesion sites, degradation of toxins, production of antimicrobial factors, and local and systemic immunomodulation.

RECENT FINDINGS

Recent studies have shown that probiotics play a role in decreasing postoperative complications in patients undergoing major gastrointestinal operations.

SUMMARY

Considering the mechanisms of action of probiotics in the gastrointestinal tract, mainly in the intestine, evidence strongly suggests that the use of these microorganisms might positively affect the complication rate in patients undergoing surgery on the gastrointestinal tract.

Spontaneous bacterial peritonitis: a therapeutic update

Spontaneous bacterial peritonitis (SBP) is one of the main infectious complications of cirrhosis and occurs in 8-30% of hospitalized patients with ascites. SBP is characterized by infection of the ascitic fluid (AF) in the absence of any primary focus of intra-abdominal infection. The main route by which the AF becomes infected is the hematogenous route. The pathogenic mechanism by which infection develops is bacterial translocation from the intestinal flora to the mesenteric lymph nodes and from there to the bloodstream. Contributing factors are an increased growth of Gram-negative aerobic bacilli in the jejunum, changes in the intestinal barrier and in addition factors which could reduce the local flow of blood. For clinical diagnosis, patients with SBP may present signs of peritoneal irritation and pain, together with changes in gastrointestinal motility, sometimes with nausea, vomiting, diarrhea or ileus. Many patients, however, may not present any symptoms or signs as a result of the presence of SBP. Diagnostic paracentesis of the AF must be performed for every patient with cirrhosis, hospitalized with ascites. Laboratory diagnosis of SBP is carried out by polymorphonuclear count in the AF, together with a positive culture from the AF, which is characteristically monomicrobial. Escherichia coli has been the main bacterium isolated from AF as well as other Gram-negative bacteria from the Enterobacteriaceae family and Streptococcus genus. A more rapid diagnosis of SBP can be obtained via the use of leukocyte esterase, which is present in biological fluids and reacts with a component of the dipstick, changing its color. During the acute phase of SBP, antibiotics should be initiated promptly once the clinical and laboratory diagnosis of SBP has been made, before the result of AF culture. Cefotaxime or other third-generation cephalosporins have been considered the first-choice empirical antibiotics in the treatment of cirrhotic patients with SBP, and is efficacious in approximately 90% of cases. Broad-spectrum quinolones, which are almost completely absorbed after oral administration and diffuse rapidly through the AF, are currently used for oral treatment of uncomplicated SBP. Patients who have already had a previous episode of SBP, with a 69% probability of recurrence within a year, will benefit from prophylactic treatment. Cirrhotic patients with a high risk of SBP and other infections, such as those with gastrointestinal bleeding, also benefit from primary prophylaxis and norfloxacin has been used with success.

Protective role of supplement with foreign Bifidobacterium and Lactobacillus in experimental hepatic ischemia-reperfusion injury

BACKGROUND AND AIM

Intestinal microflora play a crucial role in some severe liver diseases. The purpose of this study was to evaluate the effects of a Lactobacillus strain and a Bifidobacterium strain on ischemia-reperfusion (I/R) liver injury.

METHODS

Rats were divided into six groups. Each group received either Bifidobacterium Catenulatum ZYB0401; Lactobacillus Fermentum ZYL0401; a mixture of these two bacterial strains; gentamicin; or saline by daily gavage for 7 days. On the sixth day, all rats, except those in the control group, were subjected to 20 min of liver ischemia. After 22 h of hepatic reperfusion, liver enzymes and histology, malondialdehyde (MDA), superoxide dismutase (SOD), endotoxemia, serum tumor necrosis factor-alpha (TNF-alpha), intestinal bacteria, intestinal mucosal ultrastructure, and bacterial translocation were studied.

RESULTS

All administered bacteria increased intestinal Bifidobacterium and Lactobacillus, decreased endotoxemia (P < 0.01), alanine aminotransferase (ALT) (P < 0.01), and markedly ameliorated liver histology and intestinal mucosal ultrastructure. Only rats treated with Bifidobacterium Catenulatum ZYB0401 and Lactobacillus Fermentum ZYL0401 showed reduced incidence of bacterial translocation to the kidney (P < 0.05), associated with decreased serum TNF-alpha and liver MDA (P < 0.05) and increased liver SOD (P < 0.05) compared to the I/R group. Gentamicin decreased almost all kinds of intestinal bacteria (P < 0.01) and decreased ALT (P < 0.01) and serum TNF-alpha, but failed to reduce both endotoxemia and the incidence of bacterial translocation and had no effects on liver MDA and SOD.

CONCLUSION

Bifidobacterium Catenulatum ZYB0401 in combination with Lactobacillus Fermentum ZYL0401 could be useful in restoring intestinal microflora and in preventing liver injury in hepatic I/R of rats.

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.

Small intestinal bacterial overgrowth: roles of antibiotics, prebiotics, and probiotics

Small intestinal bacterial overgrowth is common in intestinal failure. Its occurrence relates to alterations in intestinal anatomy, motility, and gastric acid secretion. Its presence may contribute to symptoms, mucosal injury, and malnutrition. Relationships between bacterial overgrowth and systemic sepsis are of potential importance in the intestinal failure patient because the direct translocation of bacteria across the intestinal epithelium may contribute to systemic sepsis: a phenomenon that has been well established in experimental animal models. The accurate diagnosis of bacterial overgrowth continues to present a number of challenges in clinical practice and especially so among patients with intestinal failure. The management of patients with bacterial overgrowth remains, for the most part, primarily empiric and comprises antibiotic therapy and correction of any associated nutritional deficiencies. Although evidence from experimental animal studies consistently indicates that probiotics exert barrier-enhancing, antibacterial, immune-modulating, and anti-inflammatory effects, which all could be benefits in small intestinal bacterial overgrowth and intestinal failure, their role in human beings remains to be evaluated adequately.

Effect of Probiotic Supplementation on Bacterial Translocation in Thermal Injury

PURPOSE

To examine the effects of probiotic supplementation and enteral solutions containing glutamine and arginine on bacterial translocation (BT) and intestinal villous atrophy in thermal injury.

METHODS

Forty male Sprague-Dawley rats weighing 200-250 g were divided into four groups of ten. Group 1 served as control group without thermal injury and was fed standard chow. Thermal injury was inflicted as a 30% scald burn in the other three groups. Group 2 was fed standard chow and group 3 was fed standard chow supplemented with a probiotic (Acidophilus plus) containing Bifidobacterium bifidum, Lactobacillus acidophilus, and Lactobacillus bulgaricus (2 x 10(9) CFU/day) via an orogastric tube. Group 4 was fed only an enteral diet (Stresson multifiber) containing glutamine, arginine, and medium chain triglyceride, at 1 g/kg per day amino acid and 230 kcal/kg, for 7 days before thermal injury. All the animals were killed 24 h after thermal injury, and ileal segments were resected and examined histopathologically. To evaluate BT, samples from blood, mesenteric lymph nodes, and cecal content were cultured under aerobic and anaerobic conditions. Terminal ileum specimens were histologically examined to evaluate mucosal integrity.

RESULTS

Significantly less BT was seen in groups 3 and 4 than in group 2 (P < 0.001). No significant difference was found between groups 3 and 4. Histological evaluation showed significant reduction in villous atrophy in groups 3 and 4.

CONCLUSION

Probiotic supplementation seems to reduce bacterial translocation and decrease intestinal mucosal atrophy in rats with thermal injury, as do enteral solutions with arginine and glutamine.

Beneficial effects of a probiotic VSL#3 on parameters of liver dysfunction in chronic liver diseases

OBJECTIVES

To evaluate whether chronic therapy with probiotics affects plasma levels of cytokines and oxidative/nitrosative stress parameters, as well as liver damage, in patients with various types of chronic liver disease.

PATIENTS AND METHODS

A total of 22 nonalcoholic fatty liver disease (NAFLD) and 20 alcoholic liver cirrhosis (AC) patients were enrolled in the study and compared with 36 HCV-positive patients with chronic hepatitis without (20, CH) or with (16, CC) liver cirrhosis. All patients were treated with the probiotic VSL#3. Routine liver tests, plasma levels of tumor necrosis factor alpha (TNF-alpha), interleukin (IL)-6 and -10, malondialdehyde (MDA), and 4-hydroxynonenal (4-HNE), S-nitrosothiols (S-NO), were evaluated on days -30, 0, 90, and 120.

RESULTS

Treatment with VSL#3 exerted different effects in the various groups of patients: in NAFLD and AC groups, it significantly improved plasma levels of MDA and 4-HNE, whereas cytokines (TNF-alpha, IL-6, and IL-10) improved only in AC patients. No such effects were observed in HCV patients. Routine liver damage tests and plasma S-NO levels were improved at the end of treatment in all groups.

CONCLUSIONS

Results of the study suggest that manipulation of intestinal flora should be taken into consideration as possible adjunctive therapy in some types of chronic liver disease.

Strain-specific effects of probiotics on gut barrier integrity following hemorrhagic shock

Probiotic therapy modulates the composition of the intestinal flora and inhibits the inflammatory response. These properties may be of benefit in the preservation of gut barrier integrity after injury or stress. In this study, we examined the effect of two Lactobacillus strains selected for their pathogen exclusion properties on intestinal barrier integrity following hemorrhagic shock. Additionally, the responsiveness of the macrophage cell line RAW 264.7 to combined exposure to Lactobacillus DNA or oligodeoxynucleotides containing CpG motifs (CpG-ODN) and endotoxin was assessed by measuring tumor necrosis factor alpha (TNF-alpha) release. Rats were administered lactobacilli (5 x 10(9) CFU) or vehicle for 7 days and were subjected subsequently to hemorrhagic shock by withdrawal of 2.1 ml blood/100 g tissue. Levels of plasma endotoxin, bacterial translocation to distant organs, and filamentous actin (F-actin) in the ileum were determined 24 h later. Rats treated with Lactobacillus rhamnosus showed reduced levels of plasma endotoxin (8 +/- 2 pg/ml versus 24 +/- 4 pg/ml; P = 0.01), bacterial translocation (2 CFU/gram versus 369 CFU/gram; P < 0.01), and disruption of F-actin distribution following hemorrhagic shock compared with nontreated control rats. In contrast, pretreatment with Lactobacillus fermentum had no substantial effect on gut barrier integrity. Interestingly, DNA preparations from both lactobacilli reduced endotoxin-induced TNF-alpha release dose dependently, whereas CpG-ODN increased TNF-alpha release. In conclusion, the pathogen exclusion properties of both Lactobacillus strains and the reduction of endotoxin-induced inflammation by their DNA in vitro are not prerequisites for a beneficial effect of probiotic therapy on gut barrier function following hemorrhagic shock. Although pretreatment with Lactobacillus spp. may be useful to preserve gut barrier integrity following severe hypotension, a thorough assessment of specific strains seems to be essential.

Bacterial translocation (BT) in cirrhosis

Gut flora and bacterial translocation (BT) play an important role in the pathogenesis of the complications of cirrhosis. Research on the pathogenesis of BT and its clinical significance transcends established boundaries between microbiology, cell biology, intestinal pathophysiology, and immunology. This review delineates multiple mechanisms involved in the process of BT, with an emphasis on alterations in intestinal flora and mucosal barrier function, particularly immunological defense mechanisms. Current knowledge on the innate and adaptive immune response that allows a "friendly" communication between bacteria and host is summarized, and alterations occurring in cirrhosis that may facilitate BT are discussed. In addition, definition of a "pathological" BT is proposed together with an analysis of the anatomical site and route of BT. Finally, therapeutic approaches for the prevention of BT in experimental and human cirrhosis are reviewed. Future research in the field of BT in cirrhosis will allow the development of new therapeutic targets in the prevention of infections and other complications of cirrhosis.

Nitric oxide and the hyperdynamic circulation in cirrhosis: is there a role for selective intestinal decontamination?

Abnormal vascular tone is responsible for many of the complications seen in cirrhosis making the identification of the pathophysiology of abnormal dilatation a major focus in hepatology research. The study of abnormal vascular tone is complicated by the multiple vascular beds involved (hepatic, splanchnic, peripheral, renal and pulmonary), the differences in the underlying cause of portal hypertension (hepatic versus pre-hepatic) and the slow evolution of the hyperdynamic state. The autonomic nervous system, circulating vasodilators and abnormalities in vascular smooth muscle cells (receptors, ion channels, signalling systems and contraction) have all been implicated. There is overwhelming evidence for an overproduction of NO (nitric oxide) contributing to the peripheral dilatation in both animal models of, and in humans with, cirrhosis and portal hypertension. This review focuses on the proposal that endotoxaemia, possibly from gut-derived bacterial translocation, causes induction of NOS (NO synthase) leading to increased vascular NO production, which is the primary stimulus for the development of vasodilatation in cirrhosis and its accompanying clinical manifestations. The current controversy lies not in whether NO production is elevated, but in which isoform of NOS is responsible. We review the evidence for endotoxaemia in cirrhosis and the factors contributing to gut-derived bacterial translocation, including intestinal motility and permeability, and finally discuss the possible role of selective intestinal decontamination in the management of circulatory abnormalities in cirrhosis.

Gut microflora in the pathogenesis of the complications of cirrhosis

The gut flora plays an important role in the pathogenesis of the complications of cirrhosis. Cirrhotic patients are prone to develop bacterial infections, mainly the 'spontaneous' infection of ascites or spontaneous bacterial peritonitis. Other complications of cirrhosis, such as variceal haemorrhage and ascites, occur mostly or solely as a consequence of portal hypertension. Portal pressure increases initially as a consequence of an increased intrahepatic resistance but, once collaterals have formed, high portal pressure is maintained by an increased splanchnic blood inflow secondary to vasodilatation. Splanchnic vasodilatation is the initiating event in the hyperdynamic circulatory state that aggravates the complications of cirrhosis. The gut flora plays a role in both the development of infections and in the hyperdynamic circulatory state of cirrhosis and, although less prominently, it also plays a role in the pathogenesis of hepatic encephalopathy. This chapter presents evidence regarding gut flora and its modification in the pathogenesis and management of these complications of cirrhosis.

Probiotics and prebiotics in gastrointestinal disorders

PURPOSE OF REVIEW

This review summarizes the clinical efficacy of probiotics and prebiotics in gastrointestinal disorders and examines the mechanisms of action related to their therapeutic effect.

RECENT FINDINGS

The demonstration that immune and epithelial cells can discriminate between different microbial species has extended the known mechanism(s) of action of probiotics beyond simple barrier and antimicrobial effects. It has also confirmed that probiotic bacteria modulate mucosal and systemic immune activity and epithelial function. The progressive unraveling of these mechanisms of action has led to new credence for the use of probiotics and prebiotics in clinical medicine. Level I evidence now exists for the therapeutic use of probiotics in infectious diarrhea in children, recurrent Clostridium difficile-induced infections and postoperative pouchitis. Level II evidence is emerging for the use of probiotics in other gastrointestinal infections, prevention of postoperative bacterial translocation, irritable bowel syndrome, and in both ulcerative colitis and Crohn disease. Nevertheless, one consistent feature has emerged over the past year: Not all probiotic bacteria have similar therapeutic effects. Future clinical trials will need to incorporate this fact into trial planning and design.

SUMMARY

The use of probiotics and prebiotics as therapeutic agents for gastrointestinal disorders is rapidly moving into the "mainstream." Mechanisms of action explain the therapeutic effects and randomized; controlled trials provide the necessary evidence for their incorporation into the therapeutic armamentarium.

Portal hypertension

Portal hypertension, the main complication of cirrhosis, is responsible for its most common complications: variceal hemorrhage, ascites, and portosystemic encephalopathy. Portal hypertension is the result of increased intrahepatic resistance and increased portal venous inflow. Vasodilatation (splanchnic and systemic) and the hyperdynamic circulation are hemodynamic abnormalities typical of cirrhosis and portal hypertension. Gastroesophageal varices result almost solely from portal hypertension, although the hyperdynamic circulation contributes to variceal growth and hemorrhage. Ascites results from sinusoidal hypertension and sodium retention, which, in turn, is secondary to vasodilatation and activation of neurohumoral systems. The hepatorenal syndrome represents the result of extreme vasodilatation, with an extreme decrease in effective blood volume that leads to maximal activation of vasoconstrictive systems, renal vasoconstriction, and renal failure. Spontaneous bacterial peritonitis is a potentially lethal infection of ascites that occurs in the absence of a local source of infection. Portosystemic encephalopathy is a consequence of both portal hypertension (shunting of blood through portosystemic collaterals) and hepatic insufficiency that result in the accumulation of neurotoxins in the brain. This review covers the recent advances in the pathophysiology and management of the complications of portal hypertension.