Is Helicobacter pylori infection a critical risk factor for vascular dementia?

Gut-brain axis and vascular dementia: a review on mechanisms and Chinese herbal medicine therapeutics

Vascular dementia (VD), the second most prevalent form of dementia among the elderly population, is a cerebrovascular disorder characterized primarily by cognitive impairment. Emerging evidence has revealed that intestinal flora dysbiosis may be implicated not only in gastrointestinal (GI) pathologies but also in central nervous system (CNS) disorders, including VD. The gut-brain axis (GBA) serves as a critical bidirectional pathway through which intestinal flora influences brain physiology and function. Notably, accumulating studies have demonstrated the therapeutic potential of Chinese herbal medicine (CHM) in VD management via modulation of gut microbial composition. This review synthesizes current understanding of the VD- intestinal flora relationship mediated by the GBA, while systematically evaluating evidence for CHM interventions that ameliorate VD through intestinal flora regulation. These insights may offer novel perspectives and methodological approaches for both fundamental research and clinical management of VD.

The inter-relationship between Helicobacter pylori infection, dementia and mortality in type 2 diabetes: The Fremantle Diabetes Study Phase I

BACKGROUND

Given sparse relevant data, the aim of this study was to determine whether Helicobacter pylori infection, including cytotoxin-associated gene-A (CagA) producing strains, is associated with dementia in type 2 diabetes (T2DM).

METHODS

Longitudinal data from 1115 participants in the community-based Fremantle Diabetes Study Phase I (mean age 64.0 years, 48.0 % males; 38.0 % H. pylori seronegative, 24.3 % H. pylori seropositive/CagA seronegative, and 37.7 % H. pylori/CagA seropositive at baseline) were analyzed.

RESULTS

During up to 19 years of follow-up, 50.3 % and 83.5 % of participants without and with incident dementia, respectively, died. In Cox proportional hazards models, H. pylori/CagA seropositivity (hazard ratio (95 % CI) 1.68 (1.15, 2.46), P = 0.008), but not H. pylori seropositivity/CagA seronegativity (P = 0.541) was an independent predictor of incident dementia, but neither H. pylori seropositivity/CagA seronegativity nor H. pylori/CagA seropositivity were significant predictors in competing risks models (P ≥ 0.280).

CONCLUSIONS

Although CagA seropositivity in T2DM may have a contributory etiologic role in the risk of dementia, this may be through its association with reduced cardiovascular/all-cause mortality.

The role of digestive system diseases in cerebrovascular disease: a comprehensive Mendelian randomization study

Background

Cerebrovascular disease, among the most prevalent neurological disorders, poses a substantial threat to human health with its elevated mortality and disability rates, placing considerable strain on healthcare systems. Although several studies in recent years have suggested a potential association between digestive system diseases and cerebrovascular diseases, the findings remain inconsistent.

Methods

Genome-wide association study (GWAS) summary data for 12 digestive diseases and cerebrovascular diseases were used to conduct Mendelian randomization (MR) analysis. In this investigation, we endeavored to elucidate the causal relationship between digestive system diseases and cerebrovascular diseases. Employing a comprehensive approach, including two-sample MR (TSMR), multivariate MR (MVMR), and two-step MR analysis, we leveraged summary statistics data obtained from published GWAS. The primary analysis method employed was inverse variance weighted (IVW), with MR-Egger and weighted median (WM) as secondary methods. Sensitivity analysis included heterogeneity testing, horizontal multivariate testing, MR-PRESSO, and a "leave-one-out" method. Additionally, the F-statistic was utilized to assess the strength of instrumental variables, ensuring robust results.

Results

In the TSMR analysis, this study found a significant causal relationship between genetically predicted gastroesophageal reflux disease (GERD) and any stroke (AS), any ischemic stroke (AIS), large-artery atherosclerotic stroke (LAS), intracranial aneurysm (IA), and subarachnoid hemorrhage (SAH). In MVMR analysis, this study found that even after adjusting for systolic blood pressure (SBP), body mass index (BMI) and type 2 diabetes (T2D), the causal relationship remains exist. In the two-step MR mediation analysis, it was found that BMI, SBP and T2D play mediating role in the causal relationship between GERD and cerebrovascular diseases.

Conclusion

This study indicates a clear positive causal relationship between GERD and cerebrovascular diseases, and this causal association remains significant even after adjusting for BMI, SBP and T2D. The mediation MR analysis suggests that BMI, SBP and T2D may mediate the causal relationship between GERD and the risk of cerebrovascular diseases.

Peripheral inflammation and neurocognitive impairment: correlations, underlying mechanisms, and therapeutic implications

Cognitive impairments, such as learning and memory deficits, may occur in susceptible populations including the elderly and patients who are chronically ill or have experienced stressful events, including surgery, infection, and trauma. Accumulating lines of evidence suggested that peripheral inflammation featured by the recruitment of peripheral immune cells and the release of pro-inflammatory cytokines may be activated during aging and these conditions, participating in peripheral immune system-brain communication. Lots of progress has been achieved in deciphering the core bridging mechanism connecting peripheral inflammation and cognitive impairments, which may be helpful in developing early diagnosis, prognosis evaluation, and prevention methods based on peripheral blood circulation system sampling and intervention. In this review, we summarized the evolving evidence on the prevalence of peripheral inflammation-associated neurocognitive impairments and discussed the research advances in the underlying mechanisms. We also highlighted the prevention and treatment strategies against peripheral inflammation-associated cognitive dysfunction.

Helicobacter pylori Infection Is Associated with Long-Term Cognitive Decline in Older Adults: A Two-Year Follow-Up Study

BACKGROUND

Previous cross-sectional studies have identified a possible link between Helicobacter pylori (H. pylori) infection and dementia. However, the association of H. pylori infection with longitudinal cognitive decline has rarely been investigated.

OBJECTIVE

This cohort study aims to demonstrate the effects of H. pylori infection on longitudinal cognitive decline.

METHODS

This cohort study recruited 268 subjects with memory complaints. Among these subjects, 72 had a history of H. pylori infection, and the rest 196 subjects had no H. pylori infection. These subjects were followed up for 24 months and received cognitive assessment in fixed intervals of 12 months.

RESULTS

At baseline, H. pylori infected, and uninfected participants had no difference in MMSE scores. At 2 years of follow-up, H. pylori infected participants had lower MMSE scores than uninfected participants. H. pylori infection was associated with an increased risk of longitudinal cognitive decline, as defined by a decrease of MMSE of 3 points or more during follow-up, adjusting for age, sex, education, APOEɛ4 genotype, hypertension, diabetes, hyperlipidemia, and smoking history (HR: 2.701; 95% CI: 1.392 to 5.242). H. pylori infection was associated with larger cognitive decline during follow-up, adjusting for the above covariates (standardized coefficient: 0.282, p < 0.001). Furthermore, H. pylori infected subjects had significantly higher speed of cognitive decline than uninfected subjects during follow-up, adjusting for the above covariates.

CONCLUSION

H. pylori infection increases the risk of longitudinal cognitive decline in older subjects with memory complaints. This study is helpful for further understanding the association between infection and dementia.

Diffuse benign inflammatory gastric polyps: A rare case in a young female: Case report and review of the literature

Background

Gastric polyps are one of the most common clinical diseases arising from the mucosal surface of the stomach. The benign nature of the gastric polyp and its absence of symptoms have been widely accepted. Diffuse benign inflammatory polyps spanning the entire gastric mucosa are relatively rare in young people.

Case presentation

Our objective was to report a 20-year-old woman who presented with epigastric pain and vomiting; upper gastrointestinal barium contrast roentgenography demonstrated a huge defect in the filling of the stomach. Upper endoscopy also showed the presence of dense inflammatory polyps in the stomach that were the cause of the severe pylorus obstruction. The diffuse benign gastric polyps were diagnosed as inflammatory gastric polyps on the basis of findings on the histopathological examination. She was delivered as a result of the operating procedure of total gastrectomy and Roux-en-Y anastomosis of the esophagus and jejunum. Postoperative nutritional support therapy was also implemented. Postoperative pathological examination revealed inflammatory papillary and villous polyps distributed over the stomach, and eosinophilic infiltration was found in the local area of the polyp. Polyps move like tufts of coral. During the 16-month follow-up, patients with symptoms of malnutrition and anemia recovered.

Conclusion

Nutritional support and a total gastrectomy were used to improve this patient's symptoms of malnutrition and anemia. Surgical intervention with appropriate nutritional support should be actively performed in these patients while strengthening the differential diagnosis of hereditary disease.

Traditional Chinese medicine promotes the control and treatment of dementia

Dementia is a syndrome that impairs learning and memory. To date, there is no effective therapy for dementia. Current prescription drugs, such as cholinesterase inhibitors, fail to improve the condition of dementia and are often accompanied by severe adverse effects. In recent years, the number of studies into the use of traditional Chinese medicine (TCM) for dementia treatment has increased, revealing a formula that could significantly improve memory and cognitive dysfunctions in animal models. TCM showed fewer adverse effects, lower costs, and improved suitability for long-term use compared with currently prescribed drugs. Due to the complexity of ingredients and variations in bioactivity of herbal medicines, the multi-target nature of the traditional Chinese formula affected the outcome of dementia therapy. Innovations in TCM will create a platform for the development of new drugs for the prevention and treatment of dementia, further strengthening and enhancing the current influence of TCM.

Helicobacter pylori infection in the stomach induces neuroinflammation: the potential roles of bacterial outer membrane vesicles in an animal model of Alzheimer's disease

Helicobacter pylori (HP) is a Gram-negative bacterium that colonizes the human stomach chronically. Colonization of HP in the gastric mucosa not only causes gastrointestinal diseases, but also is associated with extra-gastric diseases, such as idiopathic thrombocytopenic purpura and neurological diseases. Among neurological diseases, epidemiological studies have shown that HP infection increases the prevalence of Alzheimer's disease (AD) and Parkinson's disease (PD). Since HP does not invade the central nervous system (CNS), it has been considered that systemic immunological changes induced by HP infection may play pathogenic roles in AD and PD. Here, we investigated the effects of HP infection on the CNS in vivo and in vitro. In the CNS, chronically HP-infected mice had microglial activation without HP colonization, although systemic immunological changes were not observed. This led us to explore the possibility that HP-derived outer membrane vesicles (HP-OMVs) could cause neuroinflammation. OMVs are small, spherical bilayer vesicles (20-500 nm) released into the extracellular space from the outer membrane of Gram-negative bacteria; OMVs contain lipopolysaccharide, proteins, peptidoglycan, DNA, and RNA. OMVs have also been shown to activate both innate and acquired immune cells in vitro, and to disrupt the tight junctions of the gastric epithelium ("leaky gut") as well as cross the blood-brain barrier in vivo. Thus, in theory, OMVs can activate immune responses in the remote organs, including the lymphoid organs and CNS, if only OMVs enter the systemic circulation. From the exosome fraction of sera from HP-infected mice, we detected HP-specific DNA, suggesting the presence of HP-OMVs. We also found that microglia incubated with HP-OMVs in vitro increased the cell proliferation, inflammatory cytokine production, and migration. On the other hand, HP-OMVs suppressed the cell proliferation of neuroblastoma in vitro. Lastly, we found that AD model mice infected with HP had amyloid plaques adjacent to activated microglia and astrocytes in vivo. Based on the literature review and our experimental data, we propose our working hypothesis that OMVs produced in chronic HP infection in the gut induce neuroinflammation in the CNS, explaining the higher prevalence of AD in HP-infected people.

Serum Irisin as a Potential Biomarker for Cognitive Decline in Vascular Dementia

Background: Irisin, a new exercise-related myokine, has been shown to be associated with a variety of diseases including serious neurological disorders. However, whether irisin is involved in the pathogenesis of vascular dementia (VD) has not yet been reported. Our aim is to determine the serum irisin level in patients with VD and investigate its relationship with cognitive function. Methods: The subjects of the study were VD patients and controls with normal cognitive function who were hospitalized in the Neck-Shoulder and Lumbocrural Pain Hospital of Shandong First Medical University from July 2018 to June 2020. Upon admission, a cognitive function assessment was performed. Enzyme-linked immunosorbent assay (ELISA) was used to determine the concentration of irisin in serum. Results: During the study period, 187 subjects (82 controls and 105 VD patients) were included in the analysis. The serum irisin level of VD patients was significantly lower than that of the control group (p < 0.001). Spearman analysis showed that irisin was positively correlated with HLD-C and MoCA, and negatively correlated with all clinical characteristics except for HCY. Logistic regression analysis showed that after adjusting for all clinical characteristics, the serum irisin of VD patients still had a significant correlation with MoCA (β = 0.304, p = 0.029). According to receiver operating characteristic (ROC) curve analysis, the diagnostic accuracy for serum irisin levels on VD was 76% with the sensitivity and 71% with specificity respectively. Conclusions: These data indicate that a decrease in serum irisin levels is a powerful biological marker for cognitive decline in patients with VD, even after adjustment for risk factors. Further multi-center studies need to confirm this connection, which may pave the way for new treatment options.

Helicobacter pylori infection and risk for developing dementia: an evidence-based meta-analysis of case-control and cohort studies

BACKGROUND

Infection with multiple pathogens may play a key role in the pathogenesis of dementia. Whether Helicobacter pylori (H. pylori) infection is associated causally with dementia is controversial.

OBJECTIVE

We conduct a meta-analysis of case-control and cohort studies on the association between H. pylori infection and the risk for all-cause and Alzheimer's disease (AD) dementia.

METHODS

Two independent reviewers searched the PubMed, Cochrane Library, and Embase databases with English language restrictions from the date of conception to September 18, 2020. The primary analysis was as follows: the exposure variable was H. pylori infection, and the outcome was incident all-cause and AD dementia. Pooled odds ratios (OR), relative risk (RR), and corresponding 95% confidence intervals (CI) were obtained using the fixed-or random-effect model. Forest plots were generated to summarize the results.

RESULTS

Ten studies involving 96,561 participants were included in the meta-analysis: 5 case-control studies and 5 cohort studies. The overall pooled cohort studies showed a significant positive association between H. pylori infection and all-cause dementia with pooled RR of 1.36 (95% CI, 1.11-1.67). There was no association between H. pylori infection and risk for developing AD: RR of 1.33 (95% CI, 0.86-2.05) in cohort studies, and OR of 1.72 (95% CI, 0.97-3.04) in case-control studies. Significant heterogeneity was showed in each comparison group.

CONCLUSION

This meta-analysis supports a positive association between H. pylori infection and the risk of all-cause dementia, but not AD dementia. Due to the interference of confounding factors, randomized controlled trials are needed to prove their causality.

Decreased Serum NCAM Levels Associated with Cognitive Impairment in Vascular Dementia

Objective

Neural cell adhesion molecule (NCAM), a glycoprotein widely distributed in the brain, has recently been shown to regulate neuroplasticity. However, the role of NCAM in vascular dementia (VaD) is still unclear. The purpose of this study is to determine whether NCAM is involved in the course of VaD.

Methods

Continuous recruitment of VaD patients and control population to join this study. Doctors or nurses are responsible for collecting their clinical characteristics including age, gender, formal education, heart rate, supine systolic blood pressure, supine diastolic blood pressure, fasting glucose, high-density lipoprotein, and low-density lipoprotein. Each participant received the Montreal Cognitive Assessment (MoCA) scale after being enrolled in the group. At the same time, their peripheral blood was collected, and their serum NCAM levels were measured by enzyme-linked immunosorbent assay (ELISA).

Results

98 VaD patients and 83 age- and sex-matched controls were enrolled. There was no significant statistical difference between the VaD group and the control group in terms of the comparison of clinical characteristics (p > 0.05). The MoCA score of VaD patients was significantly lower than that of the controls (27.9 ± 1.4 vs. 23.0 ± 2.1 points, p < 0.001). In addition, the circulating NCAM level of VaD patients was also significantly lower than that of controls (21.7 ± 3.8 vs. 17.6 ± 4.2 ng/mL, p < 0.001). The circulating NCAM level of VaD patients was significantly positively correlated with MoCA score (r = 0.285, p = 0.026). After adjusting for clinical characteristics, circulating NCAM levels are still an independent pathogenic factor of VaD (regression coefficient = 0.223, p = 0.034).

Conclusions

VaD patients have low circulating NCAM levels, which can be used as a potential predictor of VaD.

Helicobacter Pylori Infection Is Associated with Neurodegeneration in Cognitively Normal Men

BACKGROUND

An association between Helicobacter pylori (H. pylori) infection and dementia was reported in previous studies; however, the evidence is inconsistent.

OBJECTIVE

In the present study, the association between H. pylori infection and brain cortical thickness as a biomarker of neurodegeneration was investigated.

METHODS

A cross-sectional study of 822 men who underwent a medical health check-up, including an esophagogastroduodenoscopy and 3.0 T magnetic resonance imaging, was performed. H. pylori infection status was assessed based on histology. Multiple linear regression analyses were conducted to evaluate the relationship between H. pylori infection and brain cortical thickness.

RESULTS

Men with H. pylori infection exhibited overall brain cortical thinning (p = 0.022), especially in the parietal (p = 0.008) and occipital lobes (p = 0.050) compared with non-infected men after adjusting for age, educational level, alcohol intake, smoking status, and intracranial volume. 3-dimentional topographical analysis showed that H. pylori infected men had cortical thinning in the bilateral lateral temporal, lateral frontal, and right occipital areas compared with non-infected men with the same adjustments (false discovery rate corrected, Q < 0.050). The association remained significant after further adjusting for inflammatory marker (C-reactive protein) and metabolic factors (obesity, dyslipidemia, fasting glucose, and blood pressure).

CONCLUSION

Our results indicate H. pylori infection is associated with neurodegenerative changes in cognitive normal men. H. pylori infection may play a pathophysiologic role in the neurodegeneration and further studies are needed to validate this association.

Serum CCL21 as a Potential Biomarker for Cognitive Impairment in Spinal Cord Injury

Objective

Cognitive impairment is considered to be an important complication of spinal cord injury (SCI), but its underlying mechanism remains unclear. The purpose of this study is to explore whether serum CCL21 can be used as a potential biomarker of cognitive impairment in SCI.

Methods

In Neck-Shoulder and Lumbocrural Pain Hospital, Shandong First Medical University & Shandong Academy of Medical Sciences, hospitalized or treated acute SCI patients were included in the study as the SCI group (SCI). At the same time, a normal control group (NC) matching the age and sex of the SCI group was recruited in the outpatient clinic. Once the two groups were enrolled, their demographics and clinical characteristics were collected immediately. Enzyme-linked immunosorbent assay (ELISA) was used to detect serum CCL21 levels within 24 hours of admission. Three months later, the Montreal Cognitive Assessment (MoCA) was used to test the cognitive function of the population.

Results

A total of 84 SCI patients and 49 NC populations were eligible for inclusion in the study. There was no significant statistical difference in the demographics and clinical characteristics (age, gender, BMI, TG, LDL-C, FBG, SBP, and DBP) between the two groups (p > 0.05). Compared with the NC group, the SCI group had a higher serum CCL21 level (p < 0.001) and a lower MoCA score (p < 0.001). Serum CCL21 level in SCI was negatively correlated with MoCA score (p = 0.023). Multivariable analyses showed that serum CCL21 level is an independent prognostic factor of cognitive impairment in SCI.

Conclusions

MoCA score has a linear relationship with serum CCL21 quartile, and SCI cognitive function has a negative correlation with serum CCL21. Serum CCL21 is an independent risk factor for cognitive impairment after SCI.

Increased Levels of Serum Neuregulin 1 Associated with Cognitive Impairment in Vascular Dementia

Objective

Neuregulin 1 (NRG 1) is a member of the epidermal growth factor (EGF) family and is believed to play an important role in neuroplasticity. However, the relationship between NRG 1 and vascular dementia (VaD) is poorly understood. The purpose of this study is to explore the correlation between neuregulin 1 and VaD. Patients and Methods. From October 2018 to September 2020, 93 VaD patients and 79 control populations who attended Liaocheng People's Hospital were included in the study. Baseline characteristics including age, gender, years of education, HDL, LDL, FBG, SBP, and DBP are collected. At the same time, peripheral blood was collected, and the concentration of serum NRG 1 was detected by enzyme-linked immunosorbent assay (ELISA). All research subjects received professional cognitive function assessment.

Results

A total of 93 VaD patients and 79 controls were enrolled. There was no significant difference in age, gender, years of education, HDL, LDL, FBG, SBP, and DBP between the two groups (p > 0.05). However, compared with the control group, VaD patients have lower MoCA and higher serum NRG 1 levels, and the difference is statistically significant (p < 0.001). The correlation analysis of MoCA and baseline characteristics showed that the MoCA score in VaD was significantly negatively correlated with serum NRG 1 (r = −0.374, p = 0.036). The results of multivariate regression showed that the MoCA score of VaD patients was only associated with NRG 1 (β = 0.258, p = 0.012).

Conclusions

The concentration of serum NRG 1 in VaD patients is significantly increased, which may be an independent risk factor for cognitive impairment in VaD patients.

Elevated Levels of Serum Neurofilament Light Chain Associated with Cognitive Impairment in Vascular Dementia

Objective

Vascular dementia (VaD) is a progressive neurodegenerative disease with cognitive decline caused by cerebrovascular factors. Despite the great progress made in the past decade, VaD still lacks effective treatments and peripheral blood biomarkers. In this study, we tested the level of peripheral blood neurofilament light chain (NfL) in VaD patients and explored its relationship with cognitive impairment.

Method

A total of 176 study subjects including 80 normal controls (NC) and 96 VaD patients were included in our study. Upon admission, we collected clinical and biochemical characteristics of all research subjects. We also evaluate the Montreal cognitive assessment scale (MoCA) scores of all subjects. The serum NfL level was measured by the single-molecule array (Simoa) method.

Results

The years of education in the NC group and VaD group were (11.65 ± 3.04) years and (10.53 ± 3.87) years, respectively. Compared with VaD patients, the NC group has a higher level of education (p = 0.037). Furthermore, the results of Simoa indicated that VaD subjects had higher serum NfL levels compared with the NC group [(8.49 ± 2.37) pg/ml vs. (19.26 ± 4.71) pg/ml, p < 0.001]. In terms of other clinical and biochemical characteristics, there was no significant difference between VaD and NC. The Spearman correlation analysis indicated that educational years have a significant positive correlation with MoCA scores (r = 0.238, p = 0.041), while age and serum NfL levels have a significantly negative correlation with MoCA scores (age: r = -0.213, p = 0.040; NfL: r = -0.395, p = 0.027). However, further multiple regression analysis showed that only serum NfL level might serve as an independent risk factor for cognitive decline in VaD (β = 0.317, p = 0.021).

Conclusion

The serum NfL levels in VaD subjects are significantly elevated, which may be used as a potential peripheral blood marker for predicting cognitive impairment in patients with VaD.

Association of Serum FAM19A5 with Cognitive Impairment in Vascular Dementia

Objective

Family with sequence similarity 19 member A5 (FAM19A5), a novel chemokine-like peptide, is a secreted protein mainly expressed in the brain. FAM19A5 was recently found to be involved in a variety of neurological diseases; however, its correlation with vascular dementia (VaD) remains unclear. The aim of the study is to explore the association between serum FAM19A5 and cognitive impairment in subjects with VaD.

Method

136 VaD subjects and 81 normal controls were recruited in the study. Their demographic and clinical baseline data were collected on admission. All subjects received Mini-Mental State Examination (MMSE) evaluation, which was used to test their cognitive functions. A sandwich enzyme-linked immunosorbent assay (ELISA) was applied to detect the serum levels of FAM19A5.

Results

No significant differences were found between the two groups regarding the demographic and clinical baseline data (p > 0.05). The serum FAM19A5 levels were significantly higher compared to normal controls (p < 0.001). The Spearman correlation analysis indicated that serum FAM19A5 levels and MMSE scores have a significant negative correlation in VaD patients (r = −0.414, <0.001). Further multiple regression analysis indicated that serum FAM19A5 levels were independent risk predictors for cognitive functions in VaD (β = 0.419, p = 0.031).

Conclusion

The serum FAM19A5 level of VaD patients is significantly increased, which may serve as a biomarker to predict cognitive function of VaD.

Association study of serum soluble TREM2 with vascular dementia in Chinese Han population

Objective: Recent extensive evidence suggests that the triggering receptor expressed on myeloid cells 2 (TREM2) is closely implicated in the pathogenesis of Alzheimer's disease (AD). However, no relative data exist regarding vascular dementia (VD). This study aimed to investigate the association between serum soluble TREM2 (sTREM2) and vascular dementia in Chinese Han population.Methods: A total of 120 VD patients and 120 cognitively normal controls matched for age and gender were enrolled for this study. Demographic and clinical characteristics were recorded at admission. Cognitive functions were assessed by the Mini-Mental State Examination (MMSE) and serum sTREM2 levels were detected using sandwich ELISA method.Results: Demographic and clinical characteristics did not differ dramatically between groups. Serum sTREM2 levels in VD patients are significantly decreased compared with normal controls. In VD patients, the serum sTREM2 levels were positively correlated with MMSE scores (r = 0.387, p = 0.008), and the association was independent of demographic and clinical characteristics (β = 0.396, p < 0.001).Conclusion: VD patients have significantly lower serum sTREM2 levels in comparison to normal controls. Serum sTREM2 levels may be used as a potential predictive biomarker of cognitive decline in VD.

TREM2 Overexpression Attenuates Cognitive Deficits in Experimental Models of Vascular Dementia

Neuroinflammation plays a prominent role in the pathogenesis of vascular dementia (VD). Triggering receptor expressed on myeloid cells 2 (TREM2) is a transmembrane receptor mainly expressed on microglia and has been known for its anti-inflammatory properties during immune response. However, data evaluating the effects of TREM2 in VD are lacking. Therefore, the present study is aimed at investigating the role of TREM2 in VD. In this study, the mouse model of VD was induced by transient bilateral common carotid artery occlusion (BCCAO). We compared the hippocampal gene and protein expressions of TREM2 between the VD mice and sham-operated mice at different time points. The TREM2 mRNA and protein expression levels in the VD mice were higher than those in the sham-operated mice. The cognitive deficits of VD mice were observed in the Morris water maze test. Interestingly, overexpression of TREM2 by intracerebroventricular injection of a lentiviral vector that encoded TREM2 (LV-TREM2) significantly improved the spatial learning and memory and attenuated the hippocampal neural loss in VD mice. Further mechanistic study revealed that overexpression of TREM2 significantly inhibited microglia M1 polarization by decreasing inducible nitric oxide synthase (iNOS) and proinflammatory cytokines expression levels and conversely enhanced microglia M2 polarization by increasing Arginase-1 (Arg-1) and anti-inflammatory cytokine expression levels. These results strongly suggest that TREM2 provides a protective effect in VD via modulating the phenotype of activated microglia and may serve as a novel potential therapeutic target for VD.

Role of Helicobacter pylori infection in the manifestation of old age-related diseases

Helicobacter pylori is one of the most prevalent infection worldwide. It affects individuals of different age groups. Elderly people tend to resist eradication treatment and worsening of infection can lead to several gastric and non-gastric pathologies. Aging-associated cellular and molecular alteration can increase the risk of other pathologies such as osteoporosis, Alzheimer's disease, Parkinson's disease, respiratory and renal dysfunction, and cancer in geriatric patients, more than other age groups. This review article highlights some of the most common old age diseases and the role of H. pylori infection as a risk factor to worsen the conditions, presented by the molecular evidences of these associations. These studies can help clinicians to understand the underlying pathogenesis of the disease and identify high-risk patients, aiding clearer diagnosis and treatment.

Protective Effect of Hyperbaric Oxygen Therapy on Cognitive Function in Patients with Vascular Dementia

Recent studies have shown that hyperbaric oxygen (HBO) has a therapeutic effect on vascular dementia (VD); however, the exact mechanism remains unclear. This article aims to reveal the protective effects and underlying mechanisms of HBO on VD. A total of 158 patients with VD were prospectively included in the study and were randomly divided into control group and HBO group. The control group was given conventional treatment and the HBO group was treated with HBO in addition to conventional treatment. The following HBO protocol was practiced: 5 days per week, 60 min each, 100% oxygen at 2 standard atmospheric pressures for 12 weeks. The Mini-Mental State Examination (MMSE) scores and serum Humanin levels were detected before and after treatments in both groups. The baseline characteristics were not different dramatically between groups (p > 0.05). There was no significant difference in MMSE scores and serum Humanin levels between the two groups before treatment (p > 0.05). After treatment, compared with the control group, the MMSE scores and serum Humanin levels in the HBO group were significantly increased (p < 0.05). Spearman correlation analysis showed that the serum Humanin levels were positively correlated with MMSE scores (r = 0.409, p < 0.05) and this correlation was independent of baseline characteristics (β = 0.312, p < 0.05). HBO therapy can improve cognitive function in patients with VD, and its mechanism may be related to elevated serum Humanin levels.

The Impacts of Peptic Ulcer on Functional Outcomes of Ischemic Stroke

BACKGROUND AND PURPOSE

Studies have shown that peptic ulcer increased the risk of ischemic stroke and stroke recurrence. This study aimed to evaluate the impacts of peptic ulcer on functional outcomes of ischemic stroke.

METHODS

Patients with first-ever ischemic stroke were grouped as with and without history of peptic ulcer. Functional outcomes were evaluated with modified Rankin scale at 90 days after the index stroke. Favorable functional outcomes were defined as with a modified Rankin scale score of 0-2. Logistic regression was used to identify predictors for favorable functional outcomes at 90 days.

RESULTS

Among the 2577 enrolled patients with ischemic stroke, 129 (5.0%) had a history of peptic ulcer. The proportion of favorable outcome was higher in patients without peptic ulcer than those with (59.3% versus 42.6%, P < .001). Multivariate logistic analysis detected that history of peptic ulcer (odds ratio [OR] = 2.89, 95% confidence interval [CI], 1.03-8.10, P = .043), National Institute of Health Stroke Scale score (OR = 2.11, 95% CI, 1.79-2.48, P < .001), and large-artery atherosclerosis stroke subtype (OR = 4.08, 95% CI, 1.11-15.03, P = .035) decreased the likelihood of favorable outcomes.

CONCLUSIONS

Ischemic stroke patients with peptic ulcer may have an increased risk of less favorable neurological outcome at 90 days after the index stroke.

Review: Impact of Helicobacter pylori on Alzheimer's disease: What do we know so far?

BACKGROUND

Helicobacter pylori has changed radically gastroenterologic world, offering a new concept in patients' management. Over time, more medical data gave rise to diverse distant, extragastric manifestations and interactions of the "new" discovered bacterium. Special interest appeared within the field of neurodegenerative diseases and particularly Alzheimer's disease, as the latter and Helicobacter pylori infection are associated with a large public health burden and Alzheimer's disease ranks as the leading cause of disability. However, the relationship between Helicobacter pylori infection and Alzheimer's disease remains uncertain.

METHODS

We performed a narrative review regarding a possible connection between Helicobacter pylori and Alzheimer's disease. All accessible relevant (pre)clinical studies written in English were included. Both affected pathologies were briefly analyzed, and relevant studies are discussed, trying to focus on the possible pathogenetic role of this bacterium in Alzheimer's disease.

RESULTS

Data stemming from both epidemiologic studies and animal experiments seem to be rather encouraging, tending to confirm the hypothesis that Helicobacter pylori infection might influence the course of Alzheimer's disease pleiotropically. Possible main mechanisms may include the bacterium's access to the brain via the oral-nasal-olfactory pathway or by circulating monocytes (infected with Helicobacter pylori due to defective autophagy) through disrupted blood-brain barrier, thereby possibly triggering neurodegeneration.

CONCLUSIONS

Current data suggest that Helicobacter pylori infection might influence the pathophysiology of Alzheimer's disease. However, further large-scale randomized controlled trials are mandatory to clarify a possible favorable effect of Helicobacter pylori eradication on Alzheimer's disease pathophysiology, before the recommendation of short-term and cost-effective therapeutic regimens against Helicobacter pylori-related Alzheimer's disease.

The Problem of Curcumin and Its Bioavailability: Could Its Gastrointestinal Influence Contribute to Its Overall Health-Enhancing Effects?

Curcumin, from the spice turmeric, exhibits anti-inflammatory, antioxidant, anticancer, antiviral, and neurotrophic activity and therefore holds promise as a therapeutic agent to prevent and treat several disorders. However, a major barrier to curcumin's clinical efficacy is its poor bioavailability. Efforts have therefore been dedicated to developing curcumin formulations with greater bioavailability and systemic tissue distribution. However, it is proposed in this review that curcumin's potential as a therapeutic agent may not solely rely on its bioavailability, but rather its medicinal benefits may also arise from its positive influence on gastrointestinal health and function. In this review, in vitro, animal, and human studies investigating the effects of curcumin on intestinal microbiota, intestinal permeability, gut inflammation and oxidative stress, anaphylactic response, and bacterial, parasitic, and fungal infections are summarized. It is argued that positive changes in these areas can have wide-ranging influences on both intestinal and extraintestinal diseases, and therefore presents as a possible mechanism behind curcumin's therapeutic efficacy.

Helicobacter pylori infection and extragastric diseases in 2017

The huge variety of extragastric diseases linked to Helicobacter pylori infection is widely known, and new studies are conducted every year on this topic. Neurological disorders and metabolic syndrome are some of the main issues debated in the most recent literature. Articles on the association of H. pylori with skin diseases, inflammatory bowel diseases, immunologic impairment, kidney dysfunction, allergic asthma, and respiratory diseases have been published as well. In this perspective, eradication therapy for this infection could become a mandatory measure in prevention strategy.

The Correlation and Risk Factors between Carotid Intima-Media Thickening and Alcoholic Liver Disease Coupled with Helicobacter pylori Infection

The aim of this study was to explore the associations and differences in influencing factors between alcoholic liver disease (ALD) coupled with Helicobacter pylori infection and atherosclerosis and to determine whether there is a "double hit phenomenon" in atherosclerosis patients with ALD and H. pylori infections. Included cases (n = 160) were categorized into 4 groups: 41 cases of ALD coupled with H. pylori infections (group A), 35 cases of H. pylori infections without ALD (group B), 37 cases of ALD without H. pylori infections (group C), and 47 normal control cases (group D). CIMT was significantly greater in group A than in groups B and D (P = 0.005 and P = 0.001, respectively). The GLM univariate analysis found that CIMT was significantly greater in group A than in groups B, C and D (P = 0.018, P = 0.001 and P = 0.009, respectively). We found that BMI and ALT, AST and ApoB levels were independent predictors of CIMT (P = 0.000, P = 0.000, P = 0.012 and P = 0.014, respectively). ALD coupled with H. pylori infection may result in significant CIMT thickening, but H. pylori infection without ALD and ALD without H. pylori infection does not, suggesting that a "double hit phenomenon" occurs. Additionally, BMI, and ALT, AST and ApoB levels were independent risk factors for increased CIMT.

Biodiversity, the Human Microbiome and Mental Health: Moving toward a New Clinical Ecology for the 21st Century?

Advances in research concerning the brain-related influences of the microbiome have been paradigm shifting, although at an early stage, clinical research involving beneficial microbes lends credence to the notion that the microbiome may be an important target in supporting mental health (defined here along the continuum between quality of life and the criteria for specific disorders). Through metagenomics, proteomics, metabolomics, and systems biology, a new emphasis to personalized medicine is on the horizon. Humans can now be viewed as multispecies organisms operating within an ecological theatre; it is important that clinicians increasingly see their patients in this context. Historically marginalized ecological aspects of health are destined to become an important consideration in the new frontiers of practicing medicine with the microbiome in mind. Emerging evidence indicates that macrobiodiversity in the external environment can influence mental well-being. Local biodiversity may also drive differences in human-associated microbiota; microbial diversity as a product of external biodiversity may have far-reaching effects on immune function and mood. With a focus on the microbiome as it pertains to mental health, we define environmental “grey space” and emphasize a new frontier involving bio-eco-psychological medicine. Within this concept the ecological terrain can link dysbiotic lifestyles and biodiversity on the grand scale to the local human-associated microbial ecosystems that might otherwise seem far removed from one another.