The effect of Helicobacter pylori eradication on gastric juice and blood ammonia concentrations and on visual evoked potentials in cirrhotics

Association between Helicobacter pylori and extra-gastric diseases

Helicobacter pylori (H. pylori) is confirmed to be associated with many diseases such as gastric cancer, peptic ulcer, gastritis and mucosa-associated lymphoid tissue lymphoma. Recent studies found that H. pylori is associated with many extra-gastric diseases. The underlying mechanism involves autoimmunity, inflammation and oxidative stress. Here we review the association between H. pylori and extra-gastric diseases.

Association of Helicobacter pylori infection with hepatic encephalopathy risk: a systematic review

BACKGROUND

The role of Helicobacter pylori (H. pylori) in the pathogenesis of hepatic encephalopathy (HE) is still under debate. We reviewed the available evidence for a pathogenic role of H. pylori infection in determining HE in cirrhotic patients.

METHODS

We searched PubMed, EMBASE, and Cochrane Library prior to 2012 for studies that explored the role of H. pylori in HE pathogenesis.

RESULTS

Twenty studies were eligible for our analysis. Eleven studies investigated the epidemiology of H. pylori infection; there is evidence suggesting that the prevalence of H. pylori is higher in older HE patients. The evidence of nine studies failed to find that blood ammonia level was higher in H. pylori positive cirrhotic patients than in negative patients. Four studies suggested that gastric ammonia level was higher in H. pylori positive than H. pylori negative patients. Eleven studies investigated the effect of H. pylori eradication on the change of blood ammonia levels and the HE improvement. No new reliable evidence was found to support the effect of H. pylori eradication in reducing blood ammonia levels and improving HE symptoms.

CONCLUSIONS

Current evidence confirmed the higher prevalence of H. pylori infection in HE patients. However, no new evidence supported the effect of H. pylori on the increased of blood ammonia level, nor the efficacy of H. pylori eradication in decreasing of blood ammonia level and improving HE.

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.

Association of Helicobacter pylori with elevated blood ammonia levels in cirrhotic patients: a meta-analysis

PURPOSE

The association between Helicobacter pylori (H. pylori) and blood ammonia levels in cirrhotic patients is controversial. We aimed to clarify this controvercy by performing a meta-analysis of published studies.

MATERIALS AND METHODS

We searched PubMed, EMBASE and Cochrane library for studies which explored the association between H. pylori and blood ammonia levels in cirrhotic patients before May 2012. Six cohort studies involved in 632 H. pylori positive and 396 H. pylori negative cirrhotic patients were eligible for our analysis. The summary estimates were presented as standard means differences (SMD) and 95% confidence intervals (CI) from individual studies.

RESULTS

Overall, there was significant association between H. pylori infection and the elevated blood ammonia levels in cirrhotic patients (SMD=0.34, 95% CI=0.21-0.47, I²=42.1%). Sensitivity analysis further confirmed this association. Subgroup analysis showed that the association was found only in Asian ethnicity, but not in Caucasian ethnicity.

CONCLUSION

H. pylori infection is associated with elevated blood ammonia levels in cirrhotic patients, and more large scale studies and stratify analysis are warranted in order to further evaluate this association.

Effect of H pylori infection and its eradication on hyperammo-nemia and hepatic encephalopathy in cirrhotic patients

AIM: To investigate the relationship between H pylori infection, blood ammonia concentration and hepatic encephalopathy (HE), and the effect of H pylori eradication in cirrhotic patients.

METHODS: From July 2003 to January 2005, 457 cirrhotic patients in five regions of Zhejiang Province were enrolled. Patients were evaluated for demographics, number connection test, H pylori infection, liver impairment, blood ammonia concentration and HE. Patients with H pylori infection were given 1 wk therapy with omeprazole plus clarithromycin and tinidazole. ¹⁴C urea breath test was performed and mental symptoms and blood ammonia level were reassessed after bacterium eradication.

RESULTS: Overall H pylori infection rate was 60.6%, and HE occurred in 47.5% of cirrhotic patients. Subclinical HE (SHE) was detected in 55 of 117 cirrhotic patients. Blood ammonia concentration in H pylori negative (n = 180) and positive (n = 277) cirrhotic patients was 53.8 ± 51.4 and 78.4 ± 63.6 &mgr;mol/L, respectively (P < 0.01), which was significantly reduced to 53.5 ± 37.7 &mgr;mol/L after bacterium eradication (n = 126) (P < 0.01). Blood ammonia was 97.5 ± 81.0 &mgr;mol/L in H pylori-positive cirrhotic patients, and this did not significantly change in those with persistent infection after H pylori eradication (n = 11). HE was more frequently observed in patients with H pylori infection than in those without (58.5% vs 30.6%, P < 0.01). HE rate significantly dropped to 34.1% after H pylori eradiation (P < 0.01). H pylori prevalence significantly differed among cirrhotic patients with HE (74.4%), SHE (69.1%), and those without HE (53.2%) (P < 0.05). Blood ammonia level was significantly different among cirrhotic patients with HE (94.5 ± 75.6 &mgr;mol/L), SHE (59.9 ± 49.2 &mgr;mol/L), and without HE (47.3 ± 33.5 &mgr;mol/L) (P < 0.05). Logistic regression analysis showed that blood ammonia concentration, Child-Pugh stage, upper gastrointestinal bleeding, electrolyte disturbance, and urea nitrogen were risk factors for HE.

CONCLUSION: H pylori infection is an important factor for inducing high blood ammonia concentration and HE in cirrhotic patients. H pylori eradication may be helpful for treatment and prevention of HE.

Helicobacter pylori infection in hepatic encephalopathy: Relationship to plasma endotoxins and blood ammonia

BACKGROUND/AIM

Hepatic encephalopathy (HE) is frequently observed in patients with advanced liver disease and manifests a wide variety of neuropsychiatric signs and symptoms. Ammonia toxicity and bacterial endotoxins have been suggested as key determinants of HE onset whereas a role for Helicobacter pylori infection has not been established. We investigated the correlation between H. pylori infection and HE severity (evaluated through functional tests) in 60 outpatients with established liver cirrhosis and 20 non-cirrhotic controls.

METHODS

Fasting arterial blood ammonia, plasma endotoxins, and H. pylori infection status were investigated in all subjects.

RESULTS

H. pylori infection was documented in 35/60 (58%) patients and in 6/20 (30%) controls (P = 0.039). Significant differences were observed between patients with and withoutHE for age, presence of ascites, fasting arterial blood ammonia, plasma endotoxin, and H. pylori infection. Further, a significant increase in fasting arterial blood ammonia and plasma endotoxin was associated with H. pylori infection in cirrhotic patients. Last, medical treatment of H. pylori infection led to a significant decrease in HE severity and fasting arterial blood ammonia levels.

CONCLUSION

In conclusion, we submit that H. pylori infection might, in fact, play a role in increasing the circulating levels of ammonia and endotoxins in cirrhotic patients, thus facilitating the onset of HE.

Methods for diagnosing hepatic encephalopathy in patients with cirrhosis: a multidimensional approach

There is no "gold standard" for diagnosing hepatic encephalopathy in patients with cirrhosis. In consequence, the presence of this condition, unless floridly overt, is often missed. As a result, the majority of patients are denied the benefits of treatment. There are a number of individual techniques, which access different aspects of cerebral function that can be used, singly or in combination, to provide diagnostic information in this condition, including mental state assessment, psychometric testing, electroencephalography, sensory and cognitive evoked potentials, and neuroimaging. These have been variously applied to the study of hepatic encephalopathy but fundamental differences in the essential aims of the studies, as well as differences in the patient populations and the acquisition and analysis of the data, have made comparisons difficult. Thus, there is no clear consensus as to the sensitivity, specificity, or validity of these tests when used alone or in combination. There are, however, a number of additional methods that could be used to analyze the electrophysiological data, and a number of alternative evoked potentials that could be measured to provide better diagnostic information. In addition, there are a number of techniques, such as critical flicker frequency and smooth pursuit eye movements, which have not yet been applied systematically in this condition and which may provide useful diagnostic information. Clearly the methods for assessing hepatic encephalopathy need to be reviewed, newer methods for analyzing the electrophysiological data and newer techniques for assessing alternative aspects of cerebral function need to be explored for their diagnostic utility. This process should aim at developing a multidimensional diagnostic tool.

Hepatic encephalopathy and Helicobacter pylori: a critical reappraisal

Hepatic encephalopathy (HE) is a frequent complication of liver cirrhosis, and plasma ammonia plays a pivotal role in its pathogenesis. Ammonia disposal in cirrhotics depend on intricately balanced enzyme and transport systems, involving liver, large and small bowel, muscle, and kidney. Recently, it has been suggested that Helicobacter pylori could contribute to hyperammonemia in cirrhotics, but conflicting data are available in the literature. This is a systematic review of experimental (animals and humans), epidemiological, case-control, and prospective studies, to evaluate the arguments in favor and against the role of H. pylori in HE pathogenesis. Although H. pylori produces ammonia in the stomach, several studies have shown that both basal ammonia levels and HE prevalence did not significantly differ between cirrhotics with and without infection. Moreover, some prospective studies have documented that both blood ammonia levels and mental status in HE cirrhotics are not significantly affected by H. pylori eradication. Even if a small sub-group of cirrhotics with both a high bacterial density and more severe hepatic impairment seems to benefit by bacterial eradication, data indicate that ammonia production in the stomach by H. pylori urease appears to be inadequate to clinically affect ammonia disposal in the majority of cirrhotic patients. Further studies are warranted in this field.

Helicobacter pylori infection in patients with liver cirrhosis: facts and fictions

Helicobacter pylori infection could play a role in different clinical alterations observed in cirrhosis, from gastroduodenal lesions to hepatic encephalopathy. Although its prevalence in cirrhotics is similar to that in controls, H. pylori infection is responsible for the increased prevalence of peptic ulcer observed in these patients. The ammonia production by H. pylori urease does not seem to increase blood ammonia levels during cirrhosis, indicating that its role in hepatic encephalopathy could be marginalized in clinical practice. Dual and triple therapies have been shown to be equally effective for H. pylori eradication in these patients.