Laminarin-modulated osmium nanozymes with high substrate-affinity and selective peroxidase-like behavior engineered colorimetric assay for hydroxyl radical scavenging capacity estimation.

Hydroxyl radical (·OH) scavenging capacity (HOSC) estimation is essential for evaluating antioxidants, natural extracts, or drugs against clinical diseases. While nanozymes offer advantages in related applications, they still face limitations in activity and selectivity. In response, this work showcases the fabrication of laminarin-modulated osmium (laminarin-Os) nanoclusters (1.45 ± 0.05 nm), functioning as peroxidase-like nanozymes within a colorimetric assay tailored for rational HOSC estimation. This study validates both the characterization and remarkable stability of laminarin-Os. By leveraging the abundant surface negative charges of laminarin-Os and the surface hydroxyls of laminarin, oxidation reactions are facilitated, augmenting laminarin-Os's affinity for 3,3',5,5'-tetramethylbenzidine (TMB) (KM = 0.04 mM). This enables the laminarin-Os-based colorimetric assay to respond to ·OH more effectively than citrate-, albumin-, or other polysaccharides-based Os. In addition, experimental results also validate the selective peroxidase-like behavior of laminarin-Os under acidic conditions. Antioxidants like ascorbic acid, glutathione, tannic acid, and cysteine inhibit absorbance at 652 nm in the colorimetric platform using laminarin-Os's peroxidase-like activity. Compared with commercial kits, this assay demonstrates superior sensitivity (e.g., responds to ascorbic acid 0.01-0.075 mM, glutathione 1-15 µg/mL, tannic acid 0.5-5 µM, and monoammonium glycyrrhizinate cysteine 1.06-10.63 µM) and HOSC testing for glutathione, tannic acid, and monoammonium glycyrrhizinate cysteine. Overall, this study introduces a novel Os nanozyme with exceptional TMB affinity and ·OH selectivity, paving the way for HOSC estimation in biomedical research, pharmaceutical analysis, drug quality control, and beyond.

A peroxidase-like activity-based colorimetric sensor array of noble metal nanozymes to discriminate heavy metal ions.

Heavy metal ions (HMIs), including Cu2+, Ag+, Cd2+, Hg2+, and Pb2+ from the environment pose a threat to human beings and can cause a series of life-threatening diseases. Therefore, colorimetric sensors with convenience and flexibility for HMI discrimination are still required. To provide a solution, a peroxidase-like activity-based colorimetric sensor array of citrate-capped noble metal nanozymes (osmium, platinum, and gold) has been fabricated. Some studies reported that some HMIs could interact with the noble metal nanozymes leading to a change in their peroxidase-like activity. This phenomenon was confirmed in our work. Based on this principle, different concentrations of HMIs (Cu2+, Ag+, Cd2+, Hg2+, and Pb2+) were discriminated. Moreover, their practical application has been tested by discriminating HMIs in tap water and SiYu lake water. What is more, as an example of the validity of our method to quantify HMIs at nanomolar concentrations, the LOD of Hg2+ was presented. To sum up, our study not only demonstrates the differentiation ability of this nanozyme sensor array but also gives hints for using nanozyme sensor arrays for further applications.

Influences of the lncRNA TUG1-miRNA-34a-5p network on fibroblast-like synoviocytes (FLSs) dysfunction in rheumatoid arthritis through targeting the lactate dehydrogenase A (LDHA).

BACKGROUND: Rheumatoid arthritis (RA) is a systemic and chronic inflammatory disease. The cellular glucose metabolism of fibroblast-like synoviocytes (FLSs) of RA has been revealed to be essential to the pathogenesis and development of RA. To date, the precise roles and molecular mechanisms of long noncoding RNA TUG1 in RA have not been elucidated. METHODS: TUG1 and miR-34a-5p were detected by qRT-PCR. Interactions between lncRNA-miRNA and miRNA-mRNA were validated by RNA pull-down assay and luciferase assay. The glucose metabolism was evaluated by glucose uptake and extracellular acidification rate (ECAR). Cell viability was determined by MTT assay and Annexin V assay. RESULTS: TUG1 expression was significantly upregulated in synovial fibroblast-like synoviocytes (FLSs) compared with normal FLSs. Functional assays uncovered that silence of TUG1 suppressed FLSs-RA invasion, migration, glucose metabolism, and increased apoptosis. Bioinformatics analysis indicated that TUG1 interacted with miR-34a-5p. RNA pull-down assay and luciferase assay validated that TUG1 sponged miR-34a-5p in FLSs-RA. Overexpression of miR-34a-5p effectively inhibited glucose metabolism of FLSs-RA. Furthermore, the glucose metabolism of FLSs-RA was significantly elevated compared with normal FLSs. The glucose metabolism enzyme, LDHA, was directly targeted by miR-34a-5p in FLSs. Rescue experiments validated that the miR-34a-5p-inhibited glucose metabolism of FLSs-RA was through targeting LDHA. Finally, we showed restoration of miR-34a-5p in TUG1-overexpressing FLSs-RA successfully overcame the TUG1-promoted glucose metabolism and apoptosis resistance via targeting LDHA. CONCLUSION: The present study uncovered critical roles and molecular mechanisms underlying the TUG1-mediated glucose metabolism and apoptosis of FLSs-RA through modulating the miR-34a-5p-LDHA pathway in fibroblast-like synoviocytes of rheumatoid arthritis.

The impact of microplastics polystyrene on the microscopic structure of mouse intestine, tight junction genes and gut microbiota.

Microplastics, which are tiny plastic particles less than 5 mm in diameter, are widely present in the environment, have become a serious threat to aquatic life and human health, potentially causing ecosystem disorders and health problems. The present study aimed to investigate the effects of microplastics, specifically microplastics-polystyrene (MPs-PS), on the structural integrity, gene expression related to tight junctions, and gut microbiota in mice. A total of 24 Kunming mice aged 30 days were randomly assigned into four groups: control male (CM), control female (CF), PS-exposed male (PSM), and PS-exposed female (PSF)(n = 6). There were significant differences in villus height, width, intestinal surface area, and villus height to crypt depth ratio (V/C) between the PS group and the control group(C) (p <0.05). Gene expression analysis demonstrated the downregulation of Claudin-1, Claudin-2, Claudin-15, and Occludin, in both duodenum and jejunum of the PS group (p < 0.05). Analysis of microbial species using 16S rRNA sequencing indicated decreased diversity in the PSF group, as well as reduced diversity in the PSM group at various taxonomic levels. Beta diversity analysis showed a significant difference in gut microbiota distribution between the PS-exposed and C groups (R2 = 0.113, p<0.01), with this difference being more pronounced among females exposed to MPs-PS. KEGG analysis revealed enrichment of differential microbiota mainly involved in seven signaling pathways, such as nucleotide metabolism(p<0.05). The relative abundance ratio of transcriptional pathways was significantly increased for the PSF group (p<0.01), while excretory system pathways were for PSM group(p<0.05). Overall findings suggest that MPs-PS exhibit a notable sex-dependent impact on mouse gut microbiota, with a stronger effect observed among females; reduced expression of tight junction genes may be associated with dysbiosis, particularly elevated levels of Prevotellaceae.

Role of mitochondria-associated membranes in the hippocampus in the pathogenesis of depression.

BACKGROUND: Pathological changes, such as microglia activation in the hippocampus frequently occur in individuals with animal models of depression; however, they may share a common cellular mechanism, such as endoplasmic reticulum (ER) stress and mitochondrial dysfunction. Mitochondria associated membranes (MAMs) are communication platforms between ER and mitochondria. This study aimed to investigate the role of intracellular stress responses, especially structural and functional changes of MAMs in depression. METHODS: We used chronic social defeat stress (CSDS) to mimic depression in C57 mice to investigate the pathophysiological changes in the hippocampus associated with depression and assess the antidepressant effect of electroacupuncture (EA). Molecular, histological, and electron microscopic techniques were utilized to study intracellular stress responses, including the ER stress pathway reaction, mitochondrial damage, and structural and functional changes in MAMs in the hippocampus after CSDS. Proteomics technology was employed to explore protein-level changes in MAMs caused by CSDS. RESULTS: CSDS caused mitochondrial dysfunction, ER stress, closer contact between ER and mitochondria, and enrichment of functional protein clusters at MAMs in hippocampus along with depressive-like behaviors. Also, EA showed beneficial effects on intracellular stress responses and depressive-like behaviors in CSDS mice. LIMITATION: The cellular specificity of MAMs related protein changes in CSDS mice was not explored. CONCLUSIONS: In the hippocampus, ER stress and mitochondrial damage occur, along with enriched mitochondria-ER interactions and MAM-related protein enrichment, which may contribute to depression's pathophysiology. EA may improve depression by regulating intracellular stress responses.

Intracranial infection accompanied sweet's syndrome in a patient with anti-interferon-γ autoantibodies: A case report.

BACKGROUND: Several reports of adult-onset immunodeficiency syndrome have been associated with anti-interferon-gamma (IFN-γ) autoantibodies (AIGAs). However, it is rare to find AIGAs with intracranial infections. CASE SUMMARY: In this case study, we report a case of an AIGAs with intracranial infection and hand rashes considered Sweet's syndrome. The patient presented to our hospital with a persistent cough, a fever that had been going on for 6 mo, and a rash that had been going on for a week. The patient started losing consciousness gradually on the fourth day after admission, with neck stiffness and weakened limb muscles. The upper lobe of the left lung had a high-density mass with no atypia and a few inflammatory cells in the interstitium. Brain magnetic resonance imaging and cerebrospinal fluid suggest intracranial infection. The pathology of the skin damage on the right upper extremity revealed an infectious lesion that was susceptible to Sweet's disease. It has an anti-IFN-γ autoantibody titer of 1:2500. She was given empirical anti-non-tuberculous mycobacterial and antifungal treatments. The patient had no fever, obvious cough, headache, or rash on the hand. She got out of bed and took care of herself following hospitalization and discharge with medicine. CONCLUSION: Adults with severe and recurrent infections of several organs should be considered for AIGAs if no other known risk factors exist. AIGAs are susceptible to subsequent intracranial infections and Sweet's syndrome.

Effect of Helicobacter pylori eradication on blood ammonia levels in cirrhotic patients: a systematic review.

BACKGROUND/AIMS: The effect of Helicobacter pylori (H. pylori) eradication on blood ammonia levels in cirrhotic patients is still controversial. We aimed to clarify this effect by performing a quantitative meta-analysis of published studies. METHODOLOGY: We searched PubMed, EMBASE and Cochrane library for studies which explored the effect of H. pylori eradication on blood ammonia levels in cirrhotic patients before March 2012. A random-effects meta-analysis was performed. RESULTS: Nine studies (five non-randomized control studies and four before-after studies) involved in 699 cirrhotic patients who were given H. pylori eradication eligible to our analysis. The before-after studies suggested that H. pylori eradication can significantly reduce the blood ammonia levels in cirrhotic patients (SMD=0.32, 95%CI=0.11-0.53, 12=39.6%). After included five non-randomized control studies,the overall results suggested that H. pylori eradication can not reduce the blood ammonia levels in cirrhotic patients (SMD=-0.36, 95% CI=-0.83-0.11) and with significant heterogeneity (1=89.3%). Subgroup analysis suggested that the no effect was found between Caucasian and Asian ethnicity and between cirrhotic patients with Child-Pugh class B/C <70% and >70%. CONCLUSIONS: The effect of eradication of H. pylori on blood ammonia levels in cirrhotic patients is mainly caused by the non-specific effect of antibiotics regardless of patients' ethnicity and impairment of liver function. However, due to limited studies available and low methodological quality that marked by high risks of bias, our study should be interpreted cautiously.

Inhibition of lncRNA NEAT1 induces dysfunction of fibroblast-like synoviocytes in rheumatoid arthritis via miRNA-338-3p-mediated regulation of glutamine metabolism.

BACKGROUND: Rheumatoid arthritis (RA) is a systemic chronic autoimmune disease; cellular glutamine metabolism in fibroblast-like synoviocytes (FLSs) of RA was known to be essential for RA pathogenesis and progression. NEAT1, a long non-coding RNA, functions as an oncogene in diverse cancers. The exact roles and molecular mechanisms of NEAT1 in fibroblast-like synoviocytes (FLSs) of RA patients are unknown. METHODS: Expression of NEAT1 and miR-338-3p was measured by qRT-PCR. lncRNA-miRNA and miRNA-mRNA interactions were predicted from starBase and validated by RNA pull-down and luciferase assay. The glutamine metabolism of FLSs was evaluated by glutamine uptake and glutaminase activity. Cell death in FLSs in response to H2O2 was assessed by MTT and Annexin V assays. RESULTS: NEAT1 was significantly upregulated, and miR-338-3p was significantly downregulated in FLSs from RA patients compared to normal FLSs. Silencing of NEAT1 and overexpression of miR-338-3p suppressed glutamine metabolism in FLSs-RA and promoted H2O2-induced apoptosis. Bioinformatics analysis showed that NEAT1 sponges miR-338-3p to form competing endogenous RNA (ceRNAs), which was verified by RNA pull-down assay and luciferase assay FLSs-RA had an increased rate of glutamine metabolism compared to normal FLSs increased compared to normal FLSs. The results confirmed that GLS (Glutaminase), a key enzyme in glutamine metabolism, is a direct target of miR-338-3p in FLSs-RA. miR-338-3p inhibition of glutamine metabolism was verified by rescue experiments verified. Finally, restoration of miR-338-3p in FLSs-RA expressing NEAT1 overcomes NEAT1-promoted glutamine metabolism and resistance to apoptosis. CONCLUSIONS: This study reveals the essential role and molecular targets of NEAT1-regulated glutamine metabolism and FLSs-RA dysfunction in fibroblast-like synoviocytes of RA and indicates that blocking the molecular pathway via non-coding RNAs may be beneficial for RA patients.

Brain-Derived Neurotrophic Factor in the Mesolimbic Reward Circuitry Mediates Nociception in Chronic Neuropathic Pain.

BACKGROUND: The mesolimbic reward system plays a critical role in modulating nociception; however, its underlying molecular, cellular, and neural circuitry mechanisms remain unknown. METHODS: Chronic constrictive injury (CCI) of the sciatic nerve was used to model neuropathic pain. Projection-specific in vitro recordings in mouse brain slices and in vivo recordings from anesthetized animals were used to measure firing of dopaminergic neurons in the ventral tegmental area (VTA). The role of VTA-nucleus accumbens (NAc) circuitry in nociceptive regulation was assessed using optogenetic and pharmacological manipulations, and the underlying molecular mechanisms were investigated by Western blotting, enzyme-linked immunosorbent assays, and conditional knockdown techniques. RESULTS: c-Fos expression in and firing of contralateral VTA-NAc dopaminergic neurons were elevated in CCI mice, and optogenetic inhibition of these neurons reversed CCI-induced thermal hyperalgesia. CCI increased the expression of brain-derived neurotrophic factor (BDNF) protein but not messenger RNA in the contralateral NAc. This increase was reversed by pharmacological inhibition of VTA dopaminergic neuron activity, which induced an antinociceptive effect that was neutralized by injecting exogenous BDNF into the NAc. Moreover, inhibition of BDNF synthesis in the VTA with anisomycin or selective knockdown of BDNF in the VTA-NAc pathway was antinociceptive in CCI mice. CONCLUSIONS: These results reveal a novel mechanism of nociceptive modulation in the mesolimbic reward circuitry and provide new insight into the neural circuits involved in the processing of nociceptive information.

A deleterious role for Th9/IL-9 in hepatic fibrogenesis.

T helper 9 (Th9) cells, a recently recognized Th cell subset, are involved in autoimmune diseases. We aimed to investigate the role of Th9/interleukin-9 (IL-9) in the pathogenesis of hepatic fibrosis. Th9 and Th17 cells were quantified in chronic hepatitis B (CHB) patients with hepatic fibrosis, HBV-associated liver cirrhosis (LC) patients and healthy controls (HC). The percentages of Th9 and Th17 cells, concentrations of IL-9 and IL-17, as well as expression of IL-17, TNF-α, IL-6, IL-4, IL-21, TGF-ß1 and IFN-γ were significantly increased in plasma of CHB and LC patients compared with those in HC. Splenic Th9 and Th17 cells, plasma concentrations and liver expression of IL-9 and IL-17A were significantly elevated in mice with hepatic fibrosis compared with controls. Neutralization of IL-9 in mice ameliorated hepatic fibrosis, attenuated the activation of hepatic stellate cells, reduced frequencies of Th9, Th17 and Th1 cells in spleen, and suppressed expression of IL-9, IL-17A, IFN-γ, TGF-ß1, IL-6, IL-4 and TNF-α in plasma and liver respectively. Our data suggest a deleterious role of Th9/IL-9 in increasing hepatic fibrosis and exacerbating disease endpoints, indicating that Th9/IL9 based immunotherapy may be a promising approach for treating hepatic fibrosis.

Interleukin-22 ameliorates liver fibrogenesis by attenuating hepatic stellate cell activation and downregulating the levels of inflammatory cytokines.

AIM: To investigate the effect of interleukin (IL)-22 on hepatic fibrosis in mice and the possible mechanism involved. METHODS: Liver fibrosis was induced in male BALB/c mice by CCl4. Recombinant IL-22 (rmIL-22) was administered intraperitoneally in CCl4-treated mice. Fibrosis was assessed by histology and Masson staining. The activation of hepatic stellate cells (HSCs) was investigated by analysis of α-smooth muscle actin expression. The frequencies of T helper (Th) 22 cells, Th17 cells and Th1 cells, the expression of inflammatory cytokines [IL-22, IL-17A, interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), IL-6, IL-1ß] and transcription factors [aryl hydrocarbon receptor (AHR), RAR-related orphan receptor (RORγt), T-bet] mRNA in the liver were investigated. In addition, the plasma levels of IL-22, IL-17A, IFN-γ, TNF-α, IL-6 and IL-1ß were evaluated. RESULTS: Significant elevations in circulating Th22 cells, Th17 cells, Th1 cells, IL-22, IL-17A, and IFN-γ were observed in the hepatic fibrosis group compared with the control group (P < 0.01). Treatment with rmIL-22 in mice with hepatic fibrosis ameliorated the severity of hepatic fibrosis, which was confirmed by lower hepatic fibrosis pathological scores (P < 0.01). RmIL-22 decreased the frequencies of Th22 cells (6.71% ± 0.97% vs 8.09% ± 0.74%, P < 0.01), Th17 cells (4.34% ± 0.37% vs 5.71% ± 0.24%, P < 0.01), Th1 cells (3.09% ± 0.49% vs 4.91% ± 0.73%, P < 0.01), and the levels of IL-22 (56.23 ± 3.08 vs 70.29 ± 3.01, P < 0.01), IL-17A (30.74 ± 2.77 vs 45.68 ± 2.71, P < 0.01), and IFN-γ (74.78 ± 2.61 vs 124.89 ± 2.82, P < 0.01). Down-regulation of IL-22, IL-17A, IFN-γ, TNF-α, IL-6, IL-1ß, AHR RORγt, and T-bet gene expression in the liver was observed in the rmIL-22 group (P < 0.01). CONCLUSION: The frequencies of Th22, Th17 and Th1 cells are elevated in hepatic fibrosis. RmIL-22 can attenuate HSC activation and down-regulate the levels of inflammatory cytokines, thereby ameliorating liver fibrogenesis.

Nitric oxide synthase 3 gene variants and colorectal cancer: a meta-analysis.

BACKGROUND: Colorectal cancer (CRC) is the worldwide disease which causes enormous losses every year. Recent studies suggested that environmental and gene factors might be the etiologies in increasing the risk of morbidity. Nitric oxide synthase 3 (NOS3) gene polymorphisms are said to be associated with CRC risk but the conclusion is still controversial. MATERIALS AND METHODS: Pubmed and HuGENet databases up to December 2013 were used in this meta-analysis. Three different certain genotypic models were applied, namely dominant (AA+AC versus CC), recessive (AA versus AC+CC), per-allele analysis (A vs C). In addition, information on tumor sites and pathologic stages was collected. The strength of associations was assessed through combining odds ratio (OR) and 95% confidence interval (CI). RESULTS: Finally, five and three studies about the rs1799983 and rs2070744 were covered in the analysis with 2,745 cases and 2,478 controls. Three models were applied, but no significant association was found for NOS3 G894T/rs1799983 (dominant: OR=0.999, 95%CI=0.797-1.253, I2=63.8%; recessive: OR=0.924, 95%CI=0.589-1.450, I2=59.3%; allele analysis: OR=0.979, 95%CI=0.788-1.216, I2=74.9%) and T-786C/rs2070744 (dominant: OR=1.138, 95%CI=0.846-1.530, I2=67.9%; recessive: OR=0.956, 95%CI=0.708-1.291, I2=0.0%; allele analysis: OR=1.110, 95%CI=0.865-1.425, I2=69.4%). The same results were also obtained for tumor sites and pathologic stage subgroups. After further analyzing the NOS3 gene, rs1799983 as the tag- and functional SNP was presented. CONCLUSIONS: On the basis of this meta-analysis and the characteristics of the NOS3 gene, we suggested rs1799983 might be a key locus associated with CRC risk. Further prospective studies were needed to make more comprehensive explanation of the associations.

Diagnostic value of adenosine deaminase in ascites for tuberculosis ascites: a meta-analysis.

The diagnosis of tuberculosis (TB) ascites using standard diagnostic tools is difficult. The aim of the present meta-analysis was to establish the overall diagnostic accuracy of adenosine deaminase (ADA) levels in ascites for diagnosing TB ascites. A systematic review was performed of English language publications prior to April 2013. Sensitivity, specificity, and other measures of the accuracy of ADA for the diagnosis of TB ascites using ascites fluid were summarized using a random-effects model or a fixed-effects model. Receiver operating characteristic curves were used to summarize overall test performance. Seventeen studies involving 1797 subjects were eligible for the analysis. The summary estimates of sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and the area under cure of overall analysis were: 0.93, 0.94, 13.55, 0.11, 169.83, and 0.976, respectively; the results of sensitivity analysis of studies that used Giusti method were 0.94, 0.94, 12.99, 0.08, 183.18, and 0.977, respectively. Our results suggest that ADA in the ascites can be a sensitive and specific target and a critical criterion for the diagnosis of TB ascites.

Assessment by meta-analysis of interferon-gamma for the diagnosis of tuberculous peritonitis.

AIM: To investigate the performance and diagnostic accuracy of interferon-gamma (IFN-γ) for tuberculous peritonitis (TBP) by meta-analysis. METHODS: A systematic search of English language studies was performed. We searched the following electronic databases: MEDLINE, EMBASE, Web of Science, BIOSIS, LILACS and the Cochrane Library. The Standards for Reporting Diagnostic Accuracy initiative and Quality Assessment for Studies of Diagnostic Accuracy tool were used to assess the methodological quality of the studies. Sensitivity, specificity, and other measures of the accuracy of IFN-γ concentration in the diagnosis of peritoneal effusion were pooled using random-effects models. Receiver operating characteristic (ROC) curves were applied to summarize overall test performance. Two reviewers independently judged study eligibility while screening the citations. RESULTS: Six studies met the inclusion criteria. The average inter-rater agreement between the two reviewers for items in the quality checklist was 0.92. Analysis of IFN-γ level for TBP diagnosis yielded a summary estimate: sensitivity, 0.93 (95%CI, 0.87-0.97); specificity, 0.99 (95%CI, 0.97-1.00); positive likelihood ratio (PLR), 41.49 (95%CI, 18.80-91.55); negative likelihood ratio (NLR), 0.11 (95%CI, 0.06-0.19); and diagnostic odds ratio (DOR), 678.02 (95%CI, 209.91-2190.09). χ(2) values of the sensitivity, specificity, PLR, NLR and DOR were 5.66 (P = 0.3407), 6.37 (P = 0.2715), 1.38 (P = 0.9265), 5.46 (P = 0.3621) and 1.42 (P = 0.9220), respectively. The summary receiver ROC curve was positioned near the desirable upper left corner and the maximum joint sensitivity and specificity was 0.97. The area under the curve was 0.99. The evaluation of publication bias was not significant (P = 0.922). CONCLUSION: IFN-γ may be a sensitive and specific marker for the accurate diagnosis of TBP. The level of IFN-γ may contribute to the accurate differentiation of tuberculosis (TB) ascites from non-TB ascites.

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.