Helicobacter pylori Infection and Non-alcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis

An update: is there a relationship between H. pylori infection and nonalcoholic fatty liver disease? why is this subject of interest?

Helicobacter pylori (H. pylori) infection is thought to impact various extragastric diseases, including nonalcoholic fatty liver disease (NAFLD), the most common chronic liver disease. Meanwhile, the pathogenesis of NAFLD needs further research, and effective treatment for this disease remains elusive. In this mini-review, we enumerate and ponder on the evidence demonstrating an association between H. pylori infection and NAFLD. Primarily, we delve into high-quality meta-analyses and clinical randomized controlled trials focusing on the association studies between the two. We also discuss clinical studies that present opposite conclusions. In addition, we propose a mechanism through which H. pylori infection aggravates NAFLD: inflammatory cytokines and adipocytokines, insulin resistance, lipid metabolism, intestinal barrier and microbiota, H. pylori outer membrane vesicles and H. pylori-infected cell-extracellular vesicles. This mini-review aims to further explore NAFLD pathogenesis and extragastric disease mechanisms caused by H. pylori infection.

The possible role of Helicobacter pylori in liver diseases

According to previous studies, Helicobacter pylori infection is associated with liver disease. In order to better understand the risk of acquiring various liver diseases, we reviewed current knowledge on the impact of H. pylori on the onset, intensification, and progression of various liver diseases caused by the infection of H. pylori. It has been estimated that between 50 and 90% of people worldwide have been infected with H. pylori. The bacterium is mostly responsible for inflamed gastric mucosa, ulcers, and cancers associated with the gastric mucosa. Through the active antioxidant system in H. pylori, the bacteria can neutralize free radicals by synthesizing VacA, a toxin that causes cell damage and apoptosis. Furthermore, there is a possibility that CagA genes may play a role in cancer development. People who have been infected with H. pylori are likely to develop lesions in the skin, the circulation system, and the pancreas. Moreover, transferring blood from the stomach may allow H. pylori to colonize the liver. The bacterium worsened liver function during autoimmune inflammation, toxic injury, chronic HCV infection, chronic HBV infection, and liver cirrhosis. Increasing portal pressure, hyperammonemia, and esophageal varices may be associated with H pylori infection. As a result, it is crucial to diagnose and treat this infection in patients with H. pylori.

Impact of nonalcoholic fatty liver disease on clinical outcomes in patients with COVID-19 among persons living with HIV: A multicenter research network study

BACKGROUND

People living with human immunodeficiency virus (PLWH) are at an increased risk of nonalcoholic fatty liver disease (NAFLD) but how these patients react to COVID-19 infection is unclear. We examined the clinical characteristics and outcomes of patients with and without nonalcoholic fatty liver disease (NAFLD) among people living with human immunodeficiency virus (PLWH) diagnosed with COVID-19.

METHODS

A multicenter, retrospective cohort study was conducted using TriNetX. Participants diagnosed with COVID-19 between January 20, 2020, and October 31, 2021, in PLWH were identified and divided into cohorts based on preexisting NAFLD. The primary outcome was all-cause mortality, and secondary outcomes were hospitalization, severe disease, critical care, need for mechanical ventilation, and acute kidney injury(AKI). Propensity score matching (PSM) mitigated the imbalance among group covariates. Risk ratios (RR) with 95 % confidence intervals (CI) were calculated.

RESULTS

Of the 5012 PLWH identified with confirmed COVID-19 during the study period, 563 had a diagnosis of NAFLD. After PSM, both groups were well-matched with 561 patients. The primary outcome did not differ between the cohorts at 30-days, even after a fully adjusted analysis, and the risk of all-cause mortality did not differ at 60 and 90 days. NAFLD had a significantly higher risk for hospitalization rates (RR 1.32; 95 % CI, 1.06-1.63) and AKI (RR 2.55; 95 % CI 1.42-4.57) than the non-NAFLD group at 30 days. No other differences were detected in other secondary outcome measures.

CONCLUSIONS

Preexisting NAFLD is associated with an increased risk for hospitalization and AKI among PLWH infected with COVID-19. The potential role of NAFLD in developing severe COVID-19 among PLWH remains to be elucidated in future studies. Still, this study indicates the need for careful monitoring of this at-risk population.

Discussion on the common controversies of Helicobacter pylori infection

BACKGROUND

Helicobacter pylori ( H. pylori ) can persistently colonize on the gastric mucosa after infection and cause gastritis, atrophy, metaplasia, and even gastric cancer (GC).

METHODS

Therefore, the detection and eradication of H. pylori are the prerequisite.

RESULTS

Clinically, there are some controversial issues, such as why H. pylori infection is persistent, why it translocases along with the lesser curvature of the stomach, why there is oxyntic antralization, what the immunological characteristic of gastric chronic inflammation caused by H. pylori is, whether H. pylori infection is associated with extra-gastric diseases, whether chronic atrophic gastritis (CAG) is reversible, and what the potential problems are after H. pylori eradication. What are the possible answers?

CONCLUSION

In the review, we will discuss these issues from the attachment to eradication in detail.

Relationship of Helicobacter pylori Infection with Nonalcoholic Fatty Liver Disease: A Meta-Analysis

Background and Aims

Helicobacter pylori (H. pylori) and nonalcoholic fatty liver disease (NAFLD) have become increasingly recognized, both of which affect human health globally. The association of H. pylori infection with NAFLD remains unclear.

Methods

PubMed, EMBASE, and Cochrane Library databases were searched. Only a random-effects model was used. Odds ratios (ORs) and risk ratios (RRs) with 95% confidence intervals (CIs) were calculated for the combined estimates of raw data. Adjusted ORs (aORs) and hazard ratios (aHRs) with 95% CIs were calculated for the combined estimates of data adjusted for confounders.

Results

Thirty-four studies with 218573 participants were included. Based on unadjusted data from 26 cross-sectional studies and 3 case-control studies, H. pylori infection was significantly associated with the presence of NAFLD (OR = 1.26, 95% CI = 1.17-1.36, P < 0.001). Based on adjusted data from 15 cross-sectional studies and 1 case-control study, H. pylori infection was significantly associated with the presence of NAFLD (aOR = 1.25, 95% CI = 1.08-1.44, P < 0.001). Compared with control subjects without NAFLD, patients with moderate (OR = 1.67, 95% CI = 1.17-2.39, P = 0.005) and severe (OR = 1.71, 95% CI = 1.30-2.24, P < 0.001) NAFLD, but not those with mild NAFLD (OR = 1.14, 95% CI = 0.9-1.45, P = 0.286), had significantly higher proportions of H. pylori infection. The association of H. pylori infection with the occurrence of NAFLD was statistically significant based on adjusted data from 3 cohort studies (aHR = 1.18, 95% CI = 1.05-1.34, P = 0.007), but not based on unadjusted data from 3 cohort studies (RR = 1.41, 95% CI = 0.80-2.48, P = 0.237).

Conclusion

H. pylori infection is associated with NAFLD, especially moderate and severe NAFLD. The impact of H. pylori eradication on the prevention of NAFLD should be further explored.

Mucosal-Associated Invariant T Cells in the Digestive System: Defender or Destroyer?

Mucosal-associated invariant T (MAIT) cells are a subset of innate T lymphocytes that express the semi-invariant T cell receptor and recognize riboflavin metabolites via the major histocompatibility complex class I-related protein. Given the abundance of MAIT cells in the human body, their role in human diseases has been increasingly studied in recent years. MAIT cells may serve as targets for clinical therapy. Specifically, this review discusses how MAIT cells are altered in gastric, esophageal, intestinal, and hepatobiliary diseases and describes their protective or pathogenic roles. A greater understanding of MAIT cells will provide a more favorable therapeutic approach for digestive diseases in the clinical field.