Weakness of mucosal barrier in portal hypertensive gastropathy of alcoholic cirrhosis. Effects of propranolol and enprostil

IL-6-driven FasL promotes NF-κBp65/PUMA-mediated apoptosis in portal hypertensive gastropathy

Mucosal epithelial apoptosis with non-specific inflammation is an essential pathological characteristic in portal hypertensive gastropathy (PHG). However, whether a coordinated crosstalk between myeloid cells and epithelial cells involved in PHG remains unclear. IL-6, which is induced in the mucosa of PHG patients and mice, promotes FasL production via enhancing NF-κBp65 activation in myeloid cells, while blockage of IL-6 signaling by Tocilizumab or deletion of NF-κBp65 in myeloid cells attenuates the inflammatory response and Fas/FasL-mediated epithelial apoptosis in PHG. IL-6-driven FasL from myeloid cells combines with epithelial Fas receptor to encourage NF-κBp65/PUMA-mediated epithelial apoptosis in PHG, and inhibition of NF-κBp65 or knockout of PUMA alleviates Fas/FasL-mediated epithelial apoptosis in PHG. These results indicate that IL-6 drives FasL generation via NF-κBp65 in myeloid cells to promote Fas/NF-κBp65/PUMA-mediated epithelial apoptosis in PHG, and this coordinated crosstalk between myeloid cells and epithelial cells may provide a potential therapeutic target for PHG.

Mucosal miR-3677 is over-expressed in cirrhotic patients with gastric antral vascular ectasia (GAVE)

INTRODUCTION

Gastric antral vascular ectasia (GAVE) is a rare vasculopathy that associates several diseases, most commonly liver cirrhosis. It usually presents as an occult gastrointestinal bleeding leading to profound iron deficiency anemia. We hypothesized that GAVE is local mucosal pathology dependent on genetic mechanisms, and the purpose of the study was to characterize miRNAs expression in gastric tissue of patients with cirrhosis and GAVE.

MATERIALS AND METHODS

Thirteen patients with GAVE and cirrhosis and 35 healthy subjects were recruited. Microarray analysis and comparative microRNA study was done by quantitative polymerase chain reaction (qPCR). The microarray scores were grouped with use of the hierarchical clusterization analysis and miRNA target prediction was done with TargetScan 6.2 algorithm and Gene Ontology analysis (DIANA-miRPath).

RESULTS

Concentration of miR-3677 in GAVE-affected mucosa was higher by 72% in comparison with GAVE-free mucosa of patients with cirrhosis (33.7 vs. 35.6 PCR cycles; p < .001) and by 45% in comparison with normal mucosa (33.7 vs. 34.9 PCR cycles; p < .05). According to Gene Ontology analysis miR-3677 was related to angiopoietin-like protein 4 (ANGPTL4) gene.

CONCLUSION

GAVE in liver cirrhosis is associated with increased expression of miR-3667 that may be linked with ANGPTL4 gene.

Portal hypertensive gastropathy with a focus on management

Portal hypertensive gastropathy (PHG) is a painless condition of gastric mucosal ectasia and impaired mucosal defense, commonly seen in patients with elevated portal pressures. While it is typically asymptomatic and incidentally discovered on upper endoscopy, acute and chronic bleeding may occur. There are no definitive recommendations for treatment of asymptomatic PHG. Non-selective β-blockers represent the mainstay of therapy for chronic bleeding, while somatostatin and vasopressin and their derivatives may be used in conjunction with supportive measures for acute bleeding. Salvage therapy with transjugular intrahepatic portosystemic shunt or rarely surgical shunt is appropriate when medical management fails. The role of endoscopic therapy for PHG is controversial. Liver transplantation should be considered as a final resort in cases of refractory bleeding due to PHG.

Portal hypertensive gastropathy: A systematic review of the pathophysiology, clinical presentation, natural history and therapy

AIM

To describe the pathophysiology, clinical presentation, natural history, and therapy of portal hypertensive gastropathy (PHG) based on a systematic literature review.

METHODS

Computerized search of the literature was performed via PubMed using the following medical subject headings or keywords: "portal" and "gastropathy"; or "portal" and "hypertensive"; or "congestive" and "gastropathy"; or "congestive" and "gastroenteropathy". The following criteria were applied for study inclusion: Publication in peer-reviewed journals, and publication since 1980. Articles were independently evaluated by each author and selected for inclusion by consensus after discussion based on the following criteria: Well-designed, prospective trials; recent studies; large study populations; and study emphasis on PHG.

RESULTS

PHG is diagnosed by characteristic endoscopic findings of small polygonal areas of variable erythema surrounded by a pale, reticular border in a mosaic pattern in the gastric fundus/body in a patient with cirrhotic or non-cirrhotic portal hypertension. Histologic findings include capillary and venule dilatation, congestion, and tortuosity, without vascular fibrin thrombi or inflammatory cells in gastric submucosa. PHG is differentiated from gastric antral vascular ectasia by a different endoscopic appearance. The etiology of PHG is inadequately understood. Portal hypertension is necessary but insufficient to develop PHG because many patients have portal hypertension without PHG. PHG increases in frequency with more severe portal hypertension, advanced liver disease, longer liver disease duration, presence of esophageal varices, and endoscopic variceal obliteration. PHG pathogenesis is related to a hyperdynamic circulation, induced by portal hypertension, characterized by increased intrahepatic resistance to flow, increased splanchnic flow, increased total gastric flow, and most likely decreased gastric mucosal flow. Gastric mucosa in PHG shows increased susceptibility to gastrotoxic chemicals and poor wound healing. Nitrous oxide, free radicals, tumor necrosis factor-alpha, and glucagon may contribute to PHG development. Acute and chronic gastrointestinal bleeding are the only clinical complications. Bleeding is typically mild-to-moderate. Endoscopic therapy is rarely useful because the bleeding is typically diffuse. Acute bleeding is primarily treated with octreotide, often with concomitant proton pump inhibitor therapy, or secondarily treated with vasopressin or terlipressin. Nonselective β-adrenergic receptor antagonists, particularly propranolol, are used to prevent bleeding after an acute episode or for chronic bleeding. Iron deficiency anemia from chronic bleeding may require iron replacement therapy. Transjugular-intrahepatic-portosystemic-shunt and liver transplantation are highly successful ultimate therapies because they reduce the underlying portal hypertension.

CONCLUSION

PHG is important to recognize in patients with cirrhotic or non-cirrhotic portal hypertension because it can cause acute or chronic GI bleeding that often requires pharmacologic therapy.

β-Arrestin-1 protects against endoplasmic reticulum stress/p53-upregulated modulator of apoptosis-mediated apoptosis via repressing p-p65/inducible nitric oxide synthase in portal hypertensive gastropathy

Portal hypertensive gastropathy (PHG) is a serious cause of bleeding in patients, and is associated with portal hypertension. β-Arrestins (β-arrestin-1 and β-arrestin-2) are well-established mediators of endocytosis of G-protein-coupled receptors (GPCRs), ubiquitination, and G-protein-independent signaling. The role of β-arrestin-1 (β-arr1) in mucosal apoptosis in PHG remains unclear. The aim of this study was to investigate the involvement of β-arr1 in PHG via its regulation of endoplasmic reticulum (ER) stress/p53-upregulated modulator of apoptosis (PUMA) apoptotic signaling. Gastric mucosal injury and apoptosis were studied in PHG patients and in PHG mouse models. The induction of β-arr1 and the ER stress/PUMA signaling pathway were investigated, and the mechanisms of β-arr1-regulated gastric mucosal apoptosis were analyzed in vivo and in vitro experiments. β-arr1 and ER stress/PUMA signaling elements were markedly induced in the gastric mucosa of PHG patients and mouse models. Blockage of ER stress demonstrably attenuated the mucosal apoptosis of PHG, while targeted deletion of β-arr1 significantly aggravated the injury and ER stress/PUMA-mediated apoptosis. β-arr1 limited the activation of p65 to repress TNF-α-induced inducible nitric oxide synthase (iNOS) expression and NO release, which could regulate ER stress/PUMA-mediated mucosal apoptosis in PHG. In vivo and in vitro experiments further demonstrated that β-arr1 protected against mucosal apoptosis by repressing TNF-α-induced iNOS expression via inhibiting the activation of p65. These results indicated that β-arr1 regulated ER stress/PUMA-induced mucosal epithelial apoptosis through suppression of the TNF-α/p65/iNOS signaling pathway activation and that β-arr1 is a potential therapeutic target for PHG.

Portal hypertensive gastropathy and colopathy

Portal hypertensive gastropathy (PHG) and colopathy (PHC) are considered complications of portal hypertension. Both entities are clinically relevant because they may cause insidious blood loss or even acute massive gastrointestinal hemorrhage. Endoscopic evaluation is necessary for the diagnosis of PHG and PHC. The existence of different endoscopic criteria for PHG and PHC makes consensus difficult and results in a broad range of reported prevalence. Therapy targeted at reduction of portal pressure and mucosal blood flow has been used to treat acute bleeding; nonselective β-blockers are the most frequently used agents. Further studies are needed to clarify the natural history, pathogenesis, and treatment of PHG and PHC.

PUMA mediates ER stress-induced apoptosis in portal hypertensive gastropathy

Mucosal apoptosis has been demonstrated to be an essential pathological feature in portal hypertensive gastropathy (PHG). p53-upregulated modulator of apoptosis (PUMA) was identified as a BH3-only Bcl-2 family protein that has an essential role in apoptosis induced by a variety of stimuli, including endoplasmic reticulum (ER) stress. However, whether PUMA is involved in mucosal apoptosis in PHG remains unclear, and whether PUMA induces PHG by mediating ER stress remains unknown. The aim of the study is to investigate whether PUMA is involved in PHG by mediating ER stress apoptotic signaling. To identify whether PUMA is involved in PHG by mediating ER stress, gastric mucosal injury and apoptosis were studied in both PHG patients and PHG animal models using PUMA knockout (PUMA-KO) and PUMA wild-type (PUMA-WT) mice. The induction of PUMA expression and ER stress signaling were investigated, and the mechanisms of PUMA-mediated apoptosis were analyzed. GES-1 and SGC7901 cell lines were used to further identify whether PUMA-mediated apoptosis was induced by ER stress in vitro. Epithelial apoptosis and PUMA were markedly induced in the gastric mucosa of PHG patients and mouse PHG models. ER stress had a potent role in the induction of PUMA and apoptosis in PHG models, and the apoptosis was obviously attenuated in PUMA-KO mice. Although the targeted deletion of PUMA did not affect ER stress, mitochondrial apoptotic signaling was downregulated in mice. Meanwhile, PUMA knockdown significantly ameliorated ER stress-induced mitochondria-dependent apoptosis in vitro. These results indicate that PUMA mediates ER stress-induced mucosal epithelial apoptosis through the mitochondrial apoptotic pathway in PHG, and that PUMA is a potentially therapeutic target for PHG.

Effect of Helicobacter pylori infection on esophagogastric variceal bleeding in patients with liver cirrhosis and portal hypertension

BACKGROUND AND AIMS

Bleeding from esophageal and gastric varices is a fatal event in patients with liver cirrhosis and portal hypertension. However, the effects of Helicobacter pylori (H. pylori) infection on esophagogastric variceal bleeding are not known. The present study was aimed to elucidate the role of H. pylori infection in esophagogastric variceal bleeding.

METHODS

The subjects were 196 cirrhotic patients who were admitted to the Kurume University Hospital to treat their esophagogastric varices consisted of 95 with acute bleeding and 101 with nonbleeding but high risk of bleeding. For the diagnosis of H. pylori infection, a (13) C-urea breath test was used, and serum pepsinogen (PG) I and II levels and the PG I/II ratio were also measured.

RESULTS

Esophagogastric variceal bleeding was seen in 34.9% (n = 30) of the H. pylori-infected patients (n = 86) and in 59.1% (n = 65) of the noninfected patients (n = 110) (P < 0.0007). There was no significant difference in the infection rate between the bleeding sites of the esophagus and the stomach. The serum PG I and II levels and the PG I/II ratio were 65.6 ng/dL, 14.7 ng/dL, and 4.4, respectively, for the bleeding patients (n = 95), and 43.7 ng/dL, 17.7 ng/dL, and 3.1 for the nonbleeding patients (n = 101). Thus, the nonbleeding patients had significantly higher rate of H. pylori infection and lower acid secretion than bleeding patients (0.001). In addition, multivariate logistic regression analysis showed a significant negative association between H. pylori infection and esophagogastric variceal bleeding.

CONCLUSIONS

These results suggest that H. pylori infection has a protective effect against esophagogastric variceal bleeding through the induction of gastric mucosal atrophy and concomitant hypoacidity.

Gastroduodenal complications after concurrent chemoradiation therapy in patients with hepatocellular carcinoma: endoscopic findings and risk factors

PURPOSE

Concurrent chemoradiation therapy (CCRT) is useful in advanced hepatocellular carcinoma (HCC), but little is known about radiation-induced gastroduodenal complications following therapy. To determine risk factors, we investigated the prevalence and patterns of gastroduodenal complications following CCRT using endoscopy.

METHODS AND MATERIALS

Enrolled in the study were 123 patients treated with CCRT for unresectable HCC between January 1998 and December 2005. Radiation-induced gastroduodenal complications were defined as radiation gastritis/duodenitis, radiation gastric/duodenal ulcer, or other gastroduodenal toxicity associated with radiation, based on Common Terminology Criteria for Adverse Events (CTCAE 3.0). Serious gastroduodenal complications were defined as events occurring within 12 months from completion of CCRT, those requiring prompt therapeutic intervention, or symptoms equivalent to Grade 3 or 4 radiation-related gastroduodenal toxicity, including nausea or vomiting, based on CTCAE 3.0.

RESULTS

A month after completion of CCRT, 65 (52.8%) patients displayed endoscopic evidence of radiation-induced gastroduodenal complications. Radiation gastric and duodenal ulcers were found in 32 (26.0%) and 20 (16.3%) patients, respectively; radiation gastritis and duodenitis were found in 50 (40.7%) and 42 (34.1%) patients, respectively. Radiation-related bleeding was observed in 13 patients (10.6%). Serious gastroduodenal complications occurred in 18 patients (14.6%) and were significantly more frequent in patients with liver cirrhosis than in those without cirrhosis (p=0.043). There were no radiation-related deaths.

CONCLUSIONS

Endoscopically detectable radiation-induced gastroduodenal complications were common in HCC following CCRT. Although serious complications were uncommon, the frequency was higher in patients with liver cirrhosis; thus, these patients should be closely monitored when receiving CCRT.

Portal hypertensive gastropathy: a review

Portal hypertensive gastropathy (PHG) occurs as a complication of cirrhotic or non-cirrhotic portal hypertension. Although the pathogenesis of PHG is not completely understood, evidence suggests that the key factor for the development of PHG is portal hypertension. PHG is clinically important because it may cause acute (and even) massive or insidious, blood loss. The diagnosis of PHG is (only) made endoscopically; it is most often characterized by an abnormality of the gastric mucosa described as a mosaic-like pattern resembling 'snake-skin', with or without red spots and the endoscopic pattern is key its diagnosis. Unfortunately, standardization of the endoscopic diagnostic criteria for PHG is poor and consensus is generally lacking, resulting in a wide range of reported prevalence. Pharmacological therapies, presumably reducing portal pressure and gastric blood flow, have been used to treat acute bleeding; propanolol, a non-selective beta-blocker (24-480 mg/day), has been used most frequently. Endoscopic treatment for PHG bleeding plays a small, if any, role in the treatment of PHG. TIPS and shunt surgery have not been extensively analysed as a treatment for acute or chronic PHG bleeding, but they appear to lessen the severity of PHG. Secondary prophylaxis of PHG bleeding with non-selective beta-blockers is recommended. There is not enough evidence to support the use of beta-blockers in primary prophylaxis of PHG bleeding, even in cases of severe PHG (however, non-selective beta-blockers are recommended if varices are present). Further studies are needed to clarify the role of PHG in suspected chronic gastrointestinal bleeding.

Effect of laparoscopic splenectomy on portal hypertensive gastropathy in cirrhotic patients with portal hypertension

AIM

This study investigated the relationship between portal hypertensive gastropathy (PHG) and splenomegaly, and the effect of laparoscopic splenectomy on PHG in cirrhotic patients with portal hypertension.

METHODS

Seventy patients with liver cirrhosis and portal hypertension were prospectively studied. Indication for laparoscopic splenectomy was bleeding tendency in 10 patients, induction of interferon in 45, treatment of hepatocellular carcinoma in seven, and treatment for endoscopic injection sclerotherapy-resistant esophagogastric varices in eight. The severity of PHG was classified into none, mild, or severe according to the classification by McCormack et al. The severity of liver disease was classified using the Child-Pugh score. All patients underwent upper gastrointestinal endoscopy before and 1 month after the operation.

RESULTS

The prevalence of PHG was significantly correlated with the severity of liver disease using the Child-Pugh score. The severity of PHG was significantly correlated with the resected spleen volume. One month after the operation, PHG was improved in 16 of 17 patients with severe PHG and in 12 of 32 with mild PHG. The Child-Pugh score showed a significant improvement (6.8 +/- 1.4 to 6.2 +/- 1.2) at 3 months after laparoscopic splenectomy (P < 0.0001).

CONCLUSIONS

PHG may be associated with splenomegaly, and laparoscopic splenectomy may have a beneficial effect on PHG, at least for a short time.

Downregulation of cyclooxygenase-1 is involved in gastric mucosal apoptosis via death signaling in portal hypertensive rats

Portal hypertension (PHT) gastropathy is a frequent complication of liver cirrhosis and one of the leading causes of death from cirrhosis. Apoptosis is widely considered to be an active energy-dependent mode of cell death and a distinct entity from necrotic cell death. It is unclear whether gastric mucosal apoptosis is involved in PHT gastropathy. Prostaglandins (PGs) produced through cyclooxygenase (COX) are thought to play a key role in protection of the gastrointestinal mucosa from injury and apoptosis. However, the role of COX in PHT gastropathy is still not clearly understood. The aims of this study were to investigate whether (1) gastric mucosal apoptosis is involved in PHT gastropathy and (2) downregulation of COX contributes to this apoptosis. In this study, we show that gastric mucosal apoptosis was remarkably increased while mucosal proliferation was inhibited in PHT rats. Gastric mucosal COX-1 was significantly suppressed at both the mRNA and protein levels, and PGE(2) was reduced in PHT rats. Further, PGE(2) treatment suppressed gastric mucosal apoptosis in PHT rats. However, gastric mucosal COX-2 levels did not differ between sham-operated rats and PHT rats. Gastric mucosal levels of tumor necrosis factor-alpha (TNF-alpha) and Fas ligand, but not TNF-related apoptosis-inducing ligand, were increased, and activated caspase-8 and caspase-3 levels were upregulated in PHT rats. The release of cytochrome c from the mitochondria to the cytosol was not observed in PHT rats. Our data indicate that downregulation of COX-1 is involved in gastric mucosal apoptosis via death signaling-mediated type-I cell death in PHT rats.

Reduction of ethanol-induced injury in portal hypertensive gastric mucosa of rats by induction of heat shock protein 72 by geranylgeranylacetone

Portal hypertensive (PHT) gastropathy has an increased susceptibility to damage due to noxious factors. Heat shock protein (HSP) 72 has a protective effect against gastric mucosal injury and geranylgeranylacetone (GGA) is an inducer of HSP 72. However, it remains unclear how HSP 72 influences the PHT gastric mucosa. The aim of the present study was to investigate HSP 72 induction by GGA and the protective effect to gastric mucosa in PHT rats. PHT rats were produced by staged portal vein occlusion, and GGA 200 mg/kg was orally administered. Expression of HSP 72 protein in the gastric mucosa was evaluated by enzyme-linked immunosorbent assay, and gastric mucosal damage against 70% ethanol (10 mL/kg) following GGA or vehicle treatment was also estimated. Expression of mucosal HSP 72 after vehicle administration was significantly higher in the PHT rats compared with the sham-operated rats. After GGA treatment, portal pressure did not change but HSP 72 was significantly increased in the gastric mucosa of both groups. Ethanol-induced gastric mucosal damage was significantly decreased due to GGA treatment in the PHT rats, but not in the sham-operated rats. These findings suggest that HSP 72 expression is enhanced in PHT gastric mucosa and plays an important role in gastric mucosal protection. The induction of HSP 72 by GGA may therefore effectively prevent mucosal injury in the PHT stomach.

Pathology of non-infective gastritis

The discovery of Helicobacter pylori and its intimate role in the development of the most common form of chronic gastritis has elicited a much-needed interest in non-neoplastic gastric pathology. This has been paralleled by an increase in upper endoscopic examinations, which allow recognition of novel patterns and distribution of mucosal injury. Numerous attempts at classification have been made, most based on the acuteness or chronicity of gastric mucosal injury. In this review, we will not offer a new classification but present a detailed description of the major clinicopathological entities, based either on the salient morphological features or the underlying aetiologies, i.e. iatrogenic, autoimmune, vascular or idiopathic.

[Influence of nonsteroidal antiinflammatory drugs in gastrointestinal bleeding due to gastroduodenal ulcers or erosions in patients with liver cirrhosis]

INTRODUCTION

Peptic ulcer disease, with or without complications, is more common in patients with liver cirrhosis than in the general population. Factors associated with portal hypertension are involved in its pathogenesis. The prevalence of Helicobacter pylori infection in patients with liver cirrhosis and the general population is similar. The aim of the present study was to determine the influence of nonsteroidal antiinflammatory drugs (NSAIDs) in the etiology of bleeding peptic ulcer disease in patients with liver cirrhosis.

PATIENTS AND METHODS

We studied 35 patients with liver cirrhosis and gastrointestinal bleeding due to gastroduodenal ulcers or erosions (group A), 125 noncirrhotic patients with gastrointestinal bleeding due to gastroduodenal ulcers or erosions (group B), and 70 patients with liver cirrhosis who were admitted to hospital without gastrointestinal bleeding (group C). All patients were questioned about NSAID consumption, including aspirin, during the week prior to hospital admission.

RESULTS

NSAID consumption was reported by 15 patients (42.8%) in group A, 102 patients (58.2%) in group B, and 6 patients (8.5%) in group C. Statistically significant differences were obtained when the results for group A were compared with those for group C.

CONCLUSIONS

NSAID consumption in patients with liver cirrhosis without gastrointestinal bleeding was low (8.5%) and was much lower than that observed in patients with cirrhosis admitted to hospital for bleeding due to gastroduodenal ulcers or erosions (42.8%). As occurs in the general population, NSAIDs play a significant role in the pathogenesis of bleeding due to peptic ulcer disease in patients with liver cirrhosis and portal hypertension.

Diagnosis of portal hypertensive gastropathy

Portal hypertensive gastropathy is a relatively recently described entity that is an important cause of bleeding in portal hypertension. This article focuses on the endoscopic diagnosis of portal hypertensive gastropathy, including a review of different proposed scoring systems, and briefly examines the epidemiology, pathogenesis, and treatment of portal hypertensive gastropathy.

Role of acute elevation of portal venous pressure by exogenous glucagon on gastric mucosal injury in rats with portal hypertension

Time-course studies revealed the increased susceptibility of the gastric mucosa to noxious injury in portal hypertension correlates with the level of elevated portal venous pressure and hyperglucagonemia. Whether acute elevation of portal venous pressure by exogenous glucagon aggravates such injury is not known. We tested the hypothesis that glucagon in a dose sufficient to acutely elevate portal venous pressure aggravates noxious injury of the gastric mucosa in rats with portal hypertension. Infusion of a portal hypotensive dose of somatostatin should reverse these changes. In anesthetized rats with portal vein ligation, glucagon, somatostatin or the combination was administered intravenously in a randomized, coded fashion. Acidified ethanol-induced gastric mucosal injury was determined. Portal venous pressure and gastric mucosal perfusion and oxygenation (reflectance spectrophotometry) were monitored to confirm the effects of the respective intravenous treatments. Exogenous glucagon exacerbated acidified ethanol-induced gastric mucosal injury. The exacerbation was attenuated by somatostatin. These changes paralleled the portal hypertensive and hypotensive effects of glucagon and somatostatin, respectively. Our data suggest that a unique mechanism is triggered with the onset of portal hypertension. In an antagonistic manner, glucagon and somatostatin modulate this novel mechanism that controls portal venous pressure and susceptibility of the gastric mucosa to noxious injury.

Portal Hypertensive gastropathy

Portal hypertensive gastropathy (PHG), a term used to describe the endoscopic appearance of gastric mucosa with a characteristic mosaic-like pattern with or without red spots, is a common finding in patients with portal hypertension. Current classification systems that describe the severity of PHG have many limitations, but it appears that simple grading systems have better inter- and intraobserver agreement. The wide variation in the reported prevalence of PHG is probably related to selection bias, absence of uniform criteria and classification, and more importantly, the differences in inter- and intraobserver variation. Pathogenesis of PHG is not clearly defined, but there is a very close relationship between portal hypertension and development of PHG. GAVE is a separate entity from PHG, but patients with severe PHG may have a GAVE-like appearance in the gastric antrum. Acute bleeding from PHG, seen usually in the presence of severe PHG, is often mild and self-limiting. Currently, the only treatment that could be recommended for prophylaxis of bleeding from PHG is nonselective B-blockers.

Portal-hypertensive gastropathy

In the present article we describe updated information concerning the clinical feature of portal-hypertensive gastropathy (PHG), which is characterized by mucosal and submucosal vascular dilatation without inflammation. Although this lesion represents non-variceal bleeding, there is a wide variation of its prevalence. Portal pressure and some humoral factors may play important roles in its pathogenesis. Gastric acid secretory activity is reduced, whereas the gastric mucosal barrier is impaired. With regard to gastric mucosal haemodynamics, whether 'overflow' (i.e. active congestion) or 'stasis' (i.e. passive congestion) cause gastric mucosal hyperaemia is not known. A severe lesion is a potential source of bleeding, while mild lesions are of little clinical significance and endoscopic variceal obliteration aggravates PHG in some patients. In the treatment of PHG, pharmacological (e.g. propranolol), surgical (e.g. portosystemic shunt) and radiological (e.g. transjugular intrahepatic portosystemic shunt) procedures may be useful in preventing bleeding from PHG.

Underlying mechanisms of portal hypertensive gastropathy

Gastric mucosal lesions are frequently observed in patients with liver cirrhosis and portal hypertension. Similar lesions can be observed in experimental portal hypertension. This review summarizes our current knowledge of the pathophysiology of portal hypertensive gastropathy, with a particular focus on the microcirculatory disturbances that characterize this condition. The stomach of cirrhotic patients exhibits an increased susceptibility to injury induced by several irritants. Similarly, the stomach of portal hypertensive animals is less resistant to injury. One of the most important factors contributing to the increased susceptibility to damage is an impaired hyperemic response when the epithelium is exposed to irritants. This appears to be related to a reduction in mucosal prostaglandin production and to altered microcirculatory responsiveness to nitric oxide. Nitric oxide overproduction in portal hypertension may have direct effects on gastric blood flow regulation. Elevated production of tumor necrosis factor-alpha by gastric mucosa in portal hypertensive rats has also been shown to contribute to mucosal injury. A better understanding of the pathogenesis of portal hypertensive gastropathy may lead to development of specific therapeutic interventions for this condition.