Relationship between Helicobacter pylori infection and glaucoma

Glaucoma and the Human Microbiome

PURPOSE OF REVIEW

To explore a view of the human microbiome as an interconnected, functional, dynamic system that may be linked to the pathogenesis and progression of glaucoma.

METHODS

A literature review was undertaken that included publications from 1966 to 2023.

RESULTS

Bacterial lipopolysaccharides (LPS) activate toll-like receptors (TLR) and mediate the human immune response. The LPS-TLR4 pathway is a potential avenue for the ocular, gut, and oral microbiomes to interface and/or influence ocular disease. Studies of gut dysbiosis have shown that alterations in the healthy microbiota can predispose the host to immune-mediated inflammatory and neurodegenerative conditions, while oral and ocular surface dysbiosis has been correlated with glaucoma. While developmental exposure to commensal microflora has shown to be necessary for the autoimmune and neurodegenerative responses to elevated intraocular pressure to take place, commensal bacterial products like short-chain fatty acids have regulatory effects protective against glaucoma.

SUMMARY

Alterations to human microbiotas have been associated with changes in intestinal permeability, gene regulation, immune cell differentiation, and neural functioning, which may predispose the host to glaucoma. Select microbes have been highlighted for their potential contributions to glaucoma disease progression or protection, raising the potential for microbiota-based treatment modalities. Current topical glaucoma treatments may disrupt the ocular surface microbiota, potentially having ramifications on host health. Further study of the relationships between human microbiome and glaucoma is needed.

Absence of causative genetic association between Helicobacter pylori infection and glaucoma: a bidirectional two-sample mendelian randomization study

Background: While clinical research has indicated a potential link between Helicobacter pylori infection and the onset of glaucoma, the causality of this association remains uncertain due to the susceptibility of observational studies to confounding factors and reverse causation. Methods: A comprehensive two-sample bidirectional Mendelian randomization (MR) analysis was conducted to assess the causal connection between H. pylori infection and glaucoma. Glaucoma was categorized into primary open-angle glaucoma (POAG), normal tension glaucoma (NTG), and pseudo-exfoliation glaucoma (PEG). Various methods, including inverse variance weighted, MR-Egger regression, weighted median, and mode-based estimator, were employed for effect estimation and pleiotropy testing. To enhance result robustness, a sensitivity analysis was performed by excluding proxy single nucleotide polymorphisms. Results: Genetic predisposition for H. pylori infection has no causal effect on glaucoma: (OR 1.00; 95% CI 0.95-1.06, p = 0.980), (OR 0.97; 95% CI 0.86-1.09, p = 0.550), and (OR 0.99; 95% CI 0.90-1.08, p = 0.766) with POAG, NTG, and PEG, respectively. An inverse MR showed no causal effect of POAG, NTG, and PEG on H. pylori infection (OR 1.01; 95% CI 0.97-1.05, p = 0.693), (OR 1.00; 95% CI 0.98-1.03, p = 0.804), and (OR 0.99; 95% CI 0.96-1.01, p = 0.363), respectively. Heterogeneity (p > 0.05) and pleiotropy (p > 0.05) analysis confirmed the robustness of MR results. Conclusion: These results indicated that there was no genetic evidence for a causal link between H. pylori and glaucoma, suggesting that the eradication or prevention of H. pylori infection might not benefit glaucoma and vice versa.

Impact of Helicobacter pylori and metabolic syndrome on mast cell activation-related pathophysiology and neurodegeneration

Both Helicobacter pylori (H. pylori) infection and metabolic syndrome (MetS) are highly prevalent worldwide. The emergence of relevant research suggesting a pathogenic linkage between H. pylori infection and MetS-related cardio-cerebrovascular diseases and neurodegenerative disorders, particularly through mechanisms involving brain pericyte deficiency, hyperhomocysteinemia, hyperfibrinogenemia, elevated lipoprotein-a, galectin-3 overexpression, atrial fibrillation, and gut dysbiosis, has raised stimulating questions regarding their pathophysiology and its translational implications for clinicians. An additional stimulating aspect refers to H. pylori and MetS-related activation of innate immune cells, mast cells (MC), which is an important, often early, event in systemic inflammatory pathologies and related brain disorders. Synoptically, MC degranulation may play a role in the pathogenesis of H. pylori and MetS-related obesity, adipokine effects, dyslipidemia, diabetes mellitus, insulin resistance, arterial hypertension, vascular dysfunction and arterial stiffness, an early indicator of atherosclerosis associated with cardio-cerebrovascular and neurodegenerative disorders. Meningeal MC can be activated by triggers including stress and toxins resulting in vascular changes and neurodegeneration. Likewise, H.pylori and MetS-related MC activation is linked with: (a) vasculitis and thromboembolic events that increase the risk of cardio-cerebrovascular and neurodegenerative disorders, and (b) gut dysbiosis-associated neurodegeneration, whereas modulation of gut microbiota and MC activation may promote neuroprotection. This narrative review investigates the intricate relationship between H. pylori infection, MetS, MC activation, and their collective impact on pathophysiological processes linked to neurodegeneration. Through a comprehensive search of current literature, we elucidate the mechanisms through which H. pylori and MetS contribute to MC activation, subsequently triggering cascades of inflammatory responses. This highlights the role of MC as key mediators in the pathogenesis of cardio-cerebrovascular and neurodegenerative disorders, emphasizing their involvement in neuroinflammation, vascular dysfunction and, ultimately, neuronal damage. Although further research is warranted, we provide a novel perspective on the pathophysiology and management of brain disorders by exploring potential therapeutic strategies targeting H. pylori eradication, MetS management, and modulation of MC to mitigate neurodegeneration risk while promoting neuroprotection.

Microbial Dynamics in Ophthalmic Health: Exploring the Interplay between Human Microbiota and Glaucoma Pathogenesis

The human microbiome has a crucial role in the homeostasis and health of the host. These microorganisms along with their genes are involved in various processes, among these are neurological signaling, the maturation of the immune system, and the inhibition of opportunistic pathogens. In this sense, it has been shown that a healthy ocular microbiota acts as a barrier against the entry of pathogens, contributing to the prevention of infections. In recent years, a relationship has been suggested between microbiota dysbiosis and the development of neurodegenerative diseases. In patients with glaucoma, it has been observed that the microbiota of the ocular surface, intraocular cavity, oral cavity, stomach, and gut differ from those observed in healthy patients, which may suggest a role in pathology development, although the evidence remains limited. The mechanisms involved in the relationship of the human microbiome and this neurodegenerative disease remain largely unknown. For this reason, the present review aims to show a broad overview of the influence of the structure and composition of the human oral and gut microbiota and relate its dysbiosis to neurodegenerative diseases, especially glaucoma.

The role of the microbiota in glaucoma

Glaucoma is a common irreversible vision loss disorder because of the gradual loss of retinal ganglion cells (RGCs) and the optic nerve axons. Major risk factors include elder age and high intraocular pressure (IOP). However, high IOP is neither necessary nor sufficient to cause glaucoma. Some non-IOP signaling cascades can mediate RGC degeneration. In addition, gender, diet, obesity, depression, or anxiety also contribute to the development of glaucoma. Understanding the mechanism of glaucoma development is crucial for timely diagnosis and establishing new strategies to improve current IOP-reducing therapies. The microbiota exerts a marked influence on the human body during homeostasis and disease. Many glaucoma patients have abnormal compositions of the microbiota (dysbiosis) in multiple locations, including the ocular surface, intraocular cavity, oral cavity, stomach, and gut. Here, we discuss findings in the last ten years or more about the microbiota and metabolite changes in animal models, patients with three risk factors (aging, obesity, and depression), and glaucoma patients. Antigenic mimicry and heat stress protein (HSP)-specific T-cell infiltration in the retina may be responsible for commensal microbes contributing to glaucomatous RGC damage. LPS-TLR4 pathway may be the primary mechanism of oral and ocular surface dysbiosis affecting glaucoma. Microbe-derived metabolites may also affect glaucoma pathogenesis. Homocysteine accumulation, inflammatory factor release, and direct dissemination may link gastric H. pylori infection and anterior chamber viral infection (such as cytomegalovirus) to glaucoma. Potential therapeutic protocols targeting microbiota include antibiotics, modified diet, and stool transplant. Later investigations will uncover the underlying molecular mechanism connecting dysbiosis to glaucoma and its clinical applications in glaucoma management.

Association between helicobacter pylori infection and primary open-angle glaucoma: a systematic review and meta-analysis

PURPOSE

This systematic review and meta-analysis summarize the evidence for the association between Helicobacter pylori infection and Primary Open-Angle Glaucoma.

METHODS

Eligible studies reporting an association between H. pylori infection and Glaucoma were identified through an extensive search of the Excerpta Medica (EMBASE), Web of Science, Scopus, and PubMed databases and an assessment of the reference list of the top articles until October 2022. Analysis was performed with random effects model using Stata 16.

RESULT

Twenty-four studies were included in the systematic review. This study involved 1602 glaucoma patients and 2800 control individuals. The combined RRs of cohort studies and overall combined ORs of case-control studies showed a significant correlation between H. pylori infection and Glaucoma. Subgroup analysis showed that glaucoma patients had a higher risk of having H. pylori infection if they were residents of Europe countries (Cohort: RR: 1.69; 95% CI: 1.3-2.19) and (Case-Control: RR: 3.71; 95% CI: 2.07-6.64), if they had POAG type (Cohort: RR: 1.76; 95% CI: 1.37-2.27) and (Case-Control: RR: 3.71; 95% CI: 2.934.70), if their diagnostic method of HP was histology (Cohort: RR: 1.95; 95% CI: 1.26-3.01) and (Case-Control: RR: 4.06; 95% CI: 2.28-7.22), and if they were over 60 years old (Cohort: RR: 1.63; 95% CI: 1.33-2.00) and (Case-Control: RR: 2.95; 95% CI: 2.27-3.83).

DISCUSSION

The results of this meta-analysis suggest a statistically significant association between Helicobacter pylori infection and Primary Open-Angle Glaucoma.

Bifidobacterium promotes retinal ganglion cell survival by regulating the balance of retinal glial cells

INTRODUCTION

Optic nerve injury is a leading cause of irreversible blindness worldwide. The retinal ganglion cells (RGCs) and their axons cannot be regenerated once damaged. Therefore, reducing RGC damage is crucial to prevent blindness. Accordingly, we aimed to investigate the potential influence of the gut microbiota on RGC survival, as well as the associated action mechanisms.

METHODS

We evaluated the effects of microbiota, specifically Bifidobacterium, on RGC. Optic nerve crush (ONC) was used as a model of optic nerve injury. Vancomycin and Bifidobacterium were orally administered to specific pathogen-free (SPF) mice.

RESULTS

Bifidobacterium promoted RGC survival and optic nerve regeneration. The administration of Bifidobacterium inhibited microglia activation but promoted Müller cell activation, which was accompanied by the downregulation of inflammatory cytokines and upregulation of neurotrophic factors and retinal ERK/Fos signaling pathway activation.

CONCLUSIONS

Our study demonstrates that Bifidobacterium-induced changes in intestinal flora promote RGC survival. The protective effect of Bifidobacterium on RGC can be attributed to the inhibition of microglia activation and promotion of Müller cell activation and the secondary regulation of inflammatory and neurotrophic factors.

Controlling the Impact of Helicobacter pylori-Related Hyperhomocysteinemia on Neurodegeneration

Helicobacter pylori infection consists a high global burden affecting more than 50% of the world’s population. It is implicated, beyond substantiated local gastric pathologies, i.e., peptic ulcers and gastric cancer, in the pathophysiology of several neurodegenerative disorders, mainly by inducing hyperhomocysteinemia-related brain cortical thinning (BCT). BCT has been advocated as a possible biomarker associated with neurodegenerative central nervous system disorders such as Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, and/or glaucoma, termed as “ocular Alzheimer’s disease”. According to the infection hypothesis in relation to neurodegeneration, Helicobacter pylori as non-commensal gut microbiome has been advocated as trigger and/or mediator of neurodegenerative diseases, such as the development of Alzheimer’s disease. Among others, Helicobacter pylori-related inflammatory mediators, defensins, autophagy, vitamin D, dietary factors, role of probiotics, and some pathogenetic considerations including relevant involved genes are discussed within this opinion article. In conclusion, by controlling the impact of Helicobacter pylori-related hyperhomocysteinemia on neurodegenerative disorders might offer benefits, and additional research is warranted to clarify this crucial topic currently representing a major worldwide burden.

Microbiome Dysbiosis: A Pathological Mechanism at the Intersection of Obesity and Glaucoma

The rate at which obesity is becoming an epidemic in many countries is alarming. Obese individuals have a high risk of developing elevated intraocular pressure and glaucoma. Additionally, glaucoma is a disease of epidemic proportions. It is characterized by neurodegeneration and neuroinflammation with optic neuropathy and the death of retinal ganglion cells (RGC). On the other hand, there is growing interest in microbiome dysbiosis, particularly in the gut, which has been widely acknowledged to play a prominent role in the etiology of metabolic illnesses such as obesity. Recently, studies have begun to highlight the fact that microbiome dysbiosis could play a critical role in the onset and progression of several neurodegenerative diseases, as well as in the development and progression of several ocular disorders. In obese individuals, gut microbiome dysbiosis can induce endotoxemia and systemic inflammation by causing intestinal barrier malfunction. As a result, bacteria and their metabolites could be delivered via the bloodstream or mesenteric lymphatic vessels to ocular regions at the level of the retina and optic nerve, causing tissue degeneration and neuroinflammation. Nowadays, there is preliminary evidence for the existence of brain and intraocular microbiomes. The altered microbiome of the gut could perturb the resident brain-ocular microbiome ecosystem which, in turn, could exacerbate the local inflammation. All these processes, finally, could lead to the death of RGC and neurodegeneration. The purpose of this literature review is to explore the recent evidence on the role of gut microbiome dysbiosis and related inflammation as common mechanisms underlying obesity and glaucoma.

Ocular and Systemic Factors Associated with Glaucoma

Glaucoma is one of the leading causes of irreversible blindness in the world. Although numerous factors have been implicated in the pathogenesis of glaucoma, the main focus of management still remains lowering the intraocular pressure (IOP) by medical or surgical therapy. However, a major challenge is that many glaucoma patients continue to progress despite good control of IOP. In this regard, the importance of other coexisting factors that may contribute to disease progression needs to be explored. Ophthalmologists need to be aware of ocular risk factors and the impact of systemic diseases and their medications, along with lifestyle modifications on the course of glaucomatous optic neuropathy and adopt a holistic approach in treating the eye as well as the patient to alleviate the suffering from glaucoma in a comprehensive manner.

How to cite this article

Dada T, Verma S, Gagrani M, et al. Ocular and Systemic Factors associated with Glaucoma. J Curr Glaucoma Pract 2022;16(3):179-191.

Topical Glaucoma Therapy Is Associated With Alterations of the Ocular Surface Microbiome

Purpose

To investigate the ocular surface microbiome of patients with unilateral or asymmetric glaucoma being treated with topical ophthalmic medications in one eye and to determine whether microbial community changes were related to measures of ocular surface disease.

Methods

V3-V4 16S rRNA sequencing was conducted on ocular surface swabs collected from both eyes of 17 subjects: 10 patients with asymmetric/unilateral glaucoma using topical glaucoma therapy on only one eye and seven age-matched, healthy controls with no history of ocular disease or eyedrop use. Samples were categorized into three groups: patients’ glaucomatous eye treated with eyedrops, patients’ contralateral eye without eyedrops, and healthy control eyes. Comparisons were made for microbial diversity and composition, with differences in composition tested for association with ocular surface disease measures including tear meniscus height, tear break-up time, and Dry Eye Questionnaire.

Results

Samples obtained from the patients’ treated and untreated eyes both had significantly greater alpha-diversity and relative abundance of gram-negative organisms compared to healthy controls. The microbial composition of patient eyes was associated with decreased tear meniscus height and tear break-up time, whereas metagenomic predictions, based on 16S rRNA data, suggested increased synthesis of lipopolysaccharide.

Conclusions

The ocular surface microbiome of patients taking unilateral preserved glaucoma drops is characterized by a highly diverse array of gram-negative bacteria that is significantly different from the predominantly gram-positive microbes detected on healthy control eyes. These compositional differences were associated with decreased tear film measures and distinct inferred protein synthesis pathways, suggesting a potential link between microbial alterations and ocular surface inflammation.

Fine Particulate Matter Exposure Levels in Patients with Normal-Tension Glaucoma and Primary Open-Angle Glaucoma: A Population-Based Study from Taiwan

Patients with NTG or POAG with more than one outpatient or discharge diagnosis from the ophthalmology department were included in the study. These data were merged with the PM2.5 data from the Air Quality Monitoring Network for analysis. This was a case−control study, with 1006 participants in the NTG group and 2533 in the POAG group. To investigate fine particulate matter (PM2.5) exposure levels in patients with normal-tension glaucoma (NTG) and primary open-angle glaucoma (POAG), patient data were obtained from Taiwan’s Longitudinal Health Insurance Database 2000 for the 2008 to 2013 period. We used a multivariate logic regression model to assess the risk for each participant. The PM2.5 exposure levels were divided into four groups: <25th percentile (Q1), <617 μg/mm3; 25th to 50th percentile (Q2), 617 to 1297 μg/mm3; 50th to 75th percentile (Q3), 1297 to 2113 μg/mm3; and >75th percentile (Q4), >2113 μg/mm3. The results are expressed in terms of odds ratio (OR) and 95% CI. A multiple logistic regression was used to compare the results of the NTG group with those of the POAG group. Compared with the PM2.5 Q1 level, the OR of the PM2.5 Q2 level was 1.009 (95% CI 0.812−1.254), the PM2.5 Q3 level was 1.241 (95% CI 1.241−1.537, p < 0.05), and the PM2.5 Q4 level was 1.246 (95% CI 1.008−1.539, p < 0.05). Our research reveals that compared with POAG, the risk of developing NTG is more closely related with PM2.5 exposure, and PM2.5 has a concentration−dose effect. It is hoped that in the future, in the clinical judgment of NTG and POAG, the level of PM2.5 in the environment can be taken as a risk factor.

Microbiota and Ocular Diseases

Recent advances have identified significant associations between the composition and function of the gut microbiota and various disorders in organ systems other than the digestive tract. Utilizing next-generation sequencing and multiomics approaches, the microbial community that possibly impacts ocular disease has been identified. This review provides an overview of the literature on approaches to microbiota analysis and the roles of commensal microbes in ophthalmic diseases, including autoimmune uveitis, age-related macular degeneration, glaucoma, and other ocular disorders. In addition, this review discusses the hypothesis of the "gut-eye axis" and evaluates the therapeutic potential of targeting commensal microbiota to alleviate ocular inflammation.

Comparison of Medical Comorbidity between Patients with Normal-Tension Glaucoma and Primary Open-Angle Glaucoma: A Population-Based Study in Taiwan

The objective was to investigate different comorbidities developed in normal-tension glaucoma (NTG) and primary open-angle glaucoma (POAG) patients. This was a case-control study, with 1489 people in the NTG group and 5120 people in the POAG group. Patient data were obtained from the Longitudinal Health Insurance Database 2010 (LHID2010) of Taiwan for the 2008-2013 period. The chi-square test was used to compare categorical variables, such as gender, income and urbanisation level, between NTG and POAG patients, and the two-tailed t test was used to compare continuity between the two groups. We use a multivariate logic regression model to assess the risk of each participant. The results are expressed in terms of odds ratio (OR) and 95% confidence intervals (CI). Patients with NTG had significantly higher proportions of hypotension (adjusted OR, 1.984; 95% CI, 1.128-3.490), sleep disturbances (adjusted OR, 1.323; 95% CI, 1.146-1.528), peptic ulcers (adjusted OR, 1.383; 95% CI, 1.188-1.609) and allergic rhinitis (adjusted OR, 1.484; 95% CI, 1.290-1.707) than those with POAG. Conversely, arterial hypertension (adjusted OR, 0.767; 95% CI, 0.660-0.893), diabetes (adjusted OR, 0.850; 95% CI, 0.728-0.993) and atopic dermatitis (adjusted OR, 0.869; 95% CI, 0.763-0.990) had a lower risk in the NTG group than in the POAG group. We found that comorbidities such a hypotension, sleep disturbances and peptic ulcer and allergic rhinitis are more highly associated to NTG than POAG.

Association between Active Helicobacter pylori Infection and Glaucoma: A Systematic Review and Meta-Analysis

Background: Glaucoma is the second most common cause of blindness worldwide affecting almost 70 million individuals. Helicobacter pylori (H. pylori) is a widespread pathogen with systematic pathogenicity. This meta-analysis aimed to estimate the contradictory data regarding a potential association between active H. pylori infection and glaucoma. Materials and Methods: A research in MEDLINE/PubMed and Google Scholar was conducted and original studies investigating the relationship between H. pylori infection and glaucoma were included. Analysis was performed with random effects model. The main outcome was the odds ratio (OR) with 95% confidence intervals (CI) of H. pylori infection as a risk factor for glaucoma. A parallel analysis studied the role of active infection as indicated by histology and the titer of anti-H. pylori antibodies. For the anti-H. pylori antibody titers, weighted mean differences (WMD) were estimated between patients and controls. Results: Fifteen studies were included, with 2664 participants (872 patients with glaucoma and 1792 controls), divided into primary open-angle glaucoma (POAG), normal tension glaucoma (NTG) and pseudo-exfoliation glaucoma (PEG). The association between H. pylori infection and overall glaucoma was significant (OR = 2.08, CI 95% 1.48–2.93) with moderate heterogeneity (I² = 61.54%). After stratification by glaucoma subtype, heterogeneity was eliminated in the NTG subgroup. Studies with healthy controls, and controls with anemia yielded very low or no heterogeneity, respectively. Gastric biopsy to document active H. pylori infection yielded the highest OR (5.4, CI: 3.17–9.2, p < 0.001) and null heterogeneity. For anti-H. pylori antibody titers, there was a significant difference in WMD between patients and controls (WMD 15.98 IU/mL; 95% CI: 4.09–27.87; p = 0.008); values were greater in glaucoma patients, with high heterogeneity (I²: 93.8%). Meta-regression analysis showed that mean age had a significant impact on glaucoma (p = 0.037). Conclusions: Active H. pylori infection may be associated with glaucoma with null heterogeneity, as, beyond histology, quantified by anti-H. pylori titers and increases with age.

Do epigenetic changes caused by commensal microbiota contribute to development of ocular disease? A review of evidence

There is evidence that genetic polymorphisms and environmentally induced epigenetic changes play an important role in modifying disease risk. The commensal microbiota has the ability to affect the cellular environment throughout the body without requiring direct contact; for example, through the generation of a pro-inflammatory state. In this review, we discuss evidence that dysbiosis in intestinal, pharyngeal, oral, and ocular microbiome can lead to epigenetic reprogramming and inflammation making the host more susceptible to ocular disease such as autoimmune uveitis, age-related macular degeneration, and open angle glaucoma. Several mechanisms of action have been proposed to explain how changes to commensal microbiota contribute to these diseases. This is an evolving field that has potentially significant implications in the management of these conditions especially from a public health perspective.

Hellenic consensus on Helicobacter pylori infection

The Hellenic Society of Gastroenterology recently organized the “Hellenic consensus on Helicobacter pylori (H. pylori) infection”. The aim of this publication is to report the guidelines in order to aid the national gastroenterology community in the management of H. pylori infection. Forty-one delegates from all Greek regions, including gastroenterologists, pathologists, clinical microbiologists, epidemiologists and basic scientists, were invited to this meeting. The participants were allocated to 1 of the 4 main topics of the meeting: i.e., H. pylori diagnosis and association with diseases; H. pylori and gastric cancer; H. pylori and extragastric associated disorders; and H. pylori treatment. The results of each subgroup were submitted to a final consensus vote that included all participants. Relevant data based on international and Greek publications were presented, and the quality of evidence, strength of recommendation, and level of consensus were graded. The cutoff level of 70% was considered as acceptance for the final statement. It is hoped that the recommendations and conclusions of this report will guide Greek doctors in their daily practice concerning the management of H. pylori infection.

Microbial dysbiosis and microbiota-gut-retina axis: The lesson from brain neurodegenerative diseases to primary open-angle glaucoma pathogenesis of autoimmunity

In recent years, microbiota-associated neurodegenerative diseases have been exploited and provided new insight into disease pathogenesis. However, primary open-angle glaucoma (POAG), known as a complex neurodegenerative disease resulting from retinal ganglion cell death and optic nerve damage, can cause irreversible blindness and visual field loss. POAG, which shares several similarities with Parkinson's disease (PD) and Alzheimer's disease (AD), has limited studies and slow progression in the understanding of pathogenesis when compared to PD and AD. In this review, we summarized the current knowledge of POAG and commensal microbiota, combined with several lines of evidence in PD and AD to propose a possible hypothesis for POAG pathogenesis: microorganisms cause glaucoma via gut-retina axis, resulting in autoantibodies and autoreactive T cells that lead to autoimmunity. Furthermore, dual-hit hypothesis, an example of a commensal pathogen that causes PD, was partially exported in POAG. Finally, future perspectives are suggested to expand understanding of POAG.

Commensal microflora-induced T cell responses mediate progressive neurodegeneration in glaucoma

Glaucoma is the most prevalent neurodegenerative disease and a leading cause of blindness worldwide. The mechanisms causing glaucomatous neurodegeneration are not fully understood. Here we show, using mice deficient in T and/or B cells and adoptive cell transfer, that transient elevation of intraocular pressure (IOP) is sufficient to induce T-cell infiltration into the retina. This T-cell infiltration leads to a prolonged phase of retinal ganglion cell degeneration that persists after IOP returns to a normal level. Heat shock proteins (HSP) are identified as target antigens of T-cell responses in glaucomatous mice and human glaucoma patients. Furthermore, retina-infiltrating T cells cross-react with human and bacterial HSPs; mice raised in the absence of commensal microflora do not develop glaucomatous T-cell responses or the associated neurodegeneration. These results provide compelling evidence that glaucomatous neurodegeneration is mediated in part by T cells that are pre-sensitized by exposure to commensal microflora.

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.

A potential impact of Helicobacter pylori-related galectin-3 in neurodegeneration

Neurodegeneration represents a component of the central nervous system (CNS) diseases pathogenesis, either as a disability primary source in the frame of prototype neurodegenerative disorders, or as a secondary effect, following inflammation, hypoxia or neurotoxicity. Galectins are members of the lectin superfamily, a group of endogenous glycan-binding proteins, able to interact with glycosylated receptors expressed by several immune cell types. Glycan-lectin interactions play critical roles in the living systems by involving and mediating a variety of biologically important normal and pathological processes, including cell-cell signaling shaping cell communication, proliferation and migration, immune responses and fertilization, host-pathogen interactions and diseases such as neurodegenerative disorders and tumors. This review focuses in the role of Galectin-3 in shaping responses of the immune system against microbial agents, and concretely, Helicobacter pylori (Hp), thereby potentiating effect of the microbe in areas distant from the ordinary site of colonization, like the CNS. We hereby postulate that gastrointestinal Hp alterations in terms of immune cell functional phenotype, cytokine and chemokine secretion, may trigger systemic responses, thereby conferring implications for remote processes susceptible in immunity disequilibrium, namely, the CNS inflammation and/or neurodegeneration.

Are optic nerve heads of patients with helicobacter pylori infection more susceptible to glaucomatous damage?

BACKGROUND

To compare retinal nerve fiber layer thicknesses (RNFLT) of patients with or without Helicobacter pylori infection and to reveal the possible RNFLT changes after H. pylori eradication.

MATERIALS AND METHODS

Sixty-five eyes of 65 patients that tested positive for H. pylori (Group 1) and 48 eyes of 48 patients that tested negative for H. pylori (Group 2) were included. RNFLT analyses were performed with spectral-domain (SD) optical coherence tomography (OCT) in a total of five regions: the superior, inferior, nasal, and temporal quadrants and the average. Then, a comparison was made between groups. After H. pylori eradication in 38 patients, RNFLTs were compared with both pre-eradication values and Group 2.

RESULTS

The groups were similar in terms of age and gender. Temporal quadrant RNFLT was thinner in Group 1 than in Group 2 (P=.02). After H. pylori eradication, RNFLTs did not differ from pre-eradication values in Group 1 (P>.05 for all), whereas temporal quadrant RNFLT after H. pylori eradication was thinner compared to Group 2 (P=.03).

CONCLUSIONS

H. pylori may cause the localized defects on RNFL that are the early signs of glaucoma.

Choroidal Thickness of Helicobacter-Positive Patients without Central Serous Chorioretinopathy

PURPOSE

To evaluate the effect of Helicobacter pylori (H. pylori) infection on subfoveal choroidal thickness (SFCT) in patients without clinical central serous chorioretinopathy (CSC).

MATERIALS AND METHODS

This prospective study included 50 patients with pathologically proven H. pylori infection (H. pylori (+)) and 50 patients without H. pylori infection (H. pylori (-)). All of the recruited patients were previously admitted to the Gastroenterology Department of the Namik Kemal University School of Medicine over the period of July 2014 to September 2015. All patients had 20/20 vision and underwent complete ophthalmological examination, macular optical coherence tomography (OCT), and enhanced depth imaging OCT.

RESULTS

All patients had 20/20 vision and similar macular thicknesses. The mean SFCT of patients in the H. pylori (+) group was 309 ± 41.1 µm and 315 ± 18.2 µm in the H. pylori (-) group (p = 0.174). The right and left eyes of patients in the H. pylori (+) and (-) groups were not statistically significantly different (p = 0.852, p = 0.937). The age, sex, and choroidal thicknesses of patients in the H. pylori (+) and (-) groups were not correlated.

CONCLUSION

H. pylori infection does not have an effect on choroidal thickness in patients without any ocular pathology.

The study of memory and executive dysfunction in patients infected with Helicobacter pylori

Background Infectious agents are considered as potential causes of Alzheimer's disease. Recently, evidence of a high prevalence of Helicobacter pylori (H. pylori) infection in patients with Alzheimer's disease has been observed. The aim of this study was to investigate memory and executive function in H. pylori positive persons not suffering from Alzheimer's or other marked cognitive disorders. Methods This is a cross-sectional study. A total 140 participants were selected using purposive sampling from the patients within the age group of 18-60 years old at Fayyaz Bakhsh Hospital, Tehran in spring 2016. The participants were divided into two groups of H. pylori positive and negative according to results of the serologic tests to measure the levels of specific antibodies of IgA and IgG against H. pylori using ELISA method. They were subsequently assessed using two tests of Trail Making (TMT) part A and B and Wechsler Memory Scale - Third Edition. Data were analyzed using independent t-test and chi-square. The level of significance was considered P-value ≤ 0.05. Results Out of 140 participants, there were 41 male (29.3%) and 99 female (70.7%) among which 84 patients (60%) suffered from H. pylori infection (seropositive) and 56 patients (40%) were not infected. Comparison of the results using independent t-test showed a significant difference (P = 0.006) between the memory scores of patients (M: 106, SD: 8.12) and healthy ones (M: 112, SD: 1.12). In addition, the executive function showed there is a significant difference in the executive ability of seropositive individuals in the two age groups of 20-50 years old (Part A: M: 1.36, SD: 7.11, and Part B: M: 8.8, SD: 8.25 p = 0.01) and over 50 years old (Part A: M: 55, SD: 8.20, and Part B: M: 106, SD: 7.22, p = 0.009). Conclusion The results of this study showed that the infected patients have a lower cognitive performance in comparison to healthy individuals. In other words, H. pylori infection increases the prevalence of memory and executive dysfunction.

The association of Helicobacter pylori with choroidal and retinal nerve fiber layer thickness

PURPOSE

To investigate the effect of Helicobacter pylori (H. pylori) infection on choroidal thickness (CT) and retinal nerve fiber layer thickness (RNFLT).

METHODS

The study included 25 patients with H. pylori infection and 25 healthy individuals as the control group. Helicobacter pylori patients were classified as the pre-treatment (Group 1; n: 25) and the post-treatment (Group 2; n: 25). RNFLT and CT were measured before and after treatment of H. pylori infection, using enhanced depth imaging (EDI) spectral-domain optical coherence tomography (Spectralis, Heidelberg Engineering, Heidelberg, Germany). The axial length and intraocular pressure were also measured.

RESULTS

The mean subfoveal CT was 320.96 ± 29.15 μm in Group 1 and 287.48 ± 49.17 in the control group (p = 0.007), while the mean subfoveal CT did not show any difference between Group 2 and the control group (p > 0.05). No statistically significant difference was determined between the H. pylori patients and the control group in respect of RNFLT values (p > 0.05).

CONCLUSIONS

CT increases during H. pylori infection and returns to the normal range within 6 weeks of treatment. RNFLT does not show any change during H. pylori infection. The data related to the subfoveal CT may be useful in understanding the pathogenesis of central serous chorioretinopathy developing in H. pylori patients.

No Association between CagA- and VacA-Positive Strains of Helicobacter pylori and Primary Open-Angle Glaucoma: A Case-Control Study

INTRODUCTION

Glaucoma is a public health issue worldwide, particularly in Africa. In Cameroon, the prevalence rate of primary open-angle glaucoma (POAG) ranges between 4.5% and 8.2%. Helicobacter pylori (HP) has been implicated in digestive and extra-digestive diseases, including glaucoma. The objective of this work was to evaluate the implication of CagA- and VacA-positive strains of HP in POAG using a case-control design.

METHODS

An analytical study was conducted from October 2013 to December 2013. Participants were recruited in eye care centers in Yaoundé. Enzyme-linked immunosorbent assays (ELISAs) were carried out in the La Grace Laboratory in Yaoundé.

RESULTS

The total sample consisted of 50 POAG patients and 31 controls with a mean age of 58.5 ± 12.2 years and 45.5 ± 14.6 years, respectively. The prevalence rates of HP in the POAG and control groups were 74% (37/50) and 87% (27/31), respectively (P = 0.125). The prevalence rates of CagA-positive HP seropositivity in the POAG and control groups were 26% and 22.58%, respectively (P = 0.47), and the prevalence rates of VacA-positive HP participants were 6% and 0%, respectively (P = 0.22).

CONCLUSION

The HP prevalence rates among POAG patients and controls were 74% and 87%, respectively. There was no significant difference between prevalence rates of HP in the POAG and control groups. There was no association between POAG and CagA- or VacA-positive HP infection.

The Relationship Between Helicobacter pylori Infection and Open-Angle Glaucoma: A Meta-Analysis

PURPOSE

Previous studies assessed the associations between Helicobacter pylori infection and open-angle glaucoma (OAG) and produced inconsistent results. Therefore, we performed a meta-analysis to evaluate the effects of H. pylori infection on OAG risk.

METHODS

Relevant studies that reported the associations between H. pylori infection and OAG were identified through an extensive search of the Exerpta Medica Database (EMBASE), Web of Science, and PubMed databases in English and Chinese National Knowledge Infrastructure, VIP, and Wan Fang databases in Chinese, and by reviewing the reference lists of the key articles. The summary odds ratio (OR) and 95% confidence interval (CI) were calculated using the random-effects model.

RESULTS

This meta-analysis involved 695 glaucoma patients and 1580 control individuals. The overall combined ORs showed a significant correlation between H. pylori infection and OAG (OR = 2.08, 95% CI = 1.42-3.04). The subgroup analysis showed the association of H. pylori infection with primary open-angle glaucoma (POAG; OR = 3.06, 95% CI = 1.27-2.46) and normal tension glaucoma (NTG; OR = 1.77, 95% CI = 1.76-5.34), but not with pseudoexfoliation glaucoma (PXFG; OR = 1.46, 95% CI = 0.40-5.30).

CONCLUSIONS

The result of this meta-analysis suggested a statistically significant association between H. pylori infection and OAG. Further analysis showed that this positive relation is observed only in POAG and NTG patients, but not in the PXFG patients.

Does Helicobacter pylori Eradication Reduce the Risk of Open Angle Glaucoma in Patients With Peptic Ulcer Disease?

To investigate whether Helicobacter pylori (H pylori) eradication would influence the risk of primary open angle glaucoma (POAG) in patients with peptic ulcer disease. From the Longitudinal Health Insurance Database 2000, 6061 patients with peptic ulcer and receiving H pylori eradication therapy were recruited. The study cohort was subdivided into early (within 1 year) and late (after 1 year) eradication cohorts. The 24,244 control cohort subjects were those who without peptic ulcer and without receiving H pylori eradication therapy and were frequency-matched with the H pylori eradication cohort by age, sex, and the year of receiving H pylori eradication therapy. The higher incidence of POAG was observed in late H pylori eradication cohort and in early H pylori eradication cohort than in control cohort (1.57, 1.32, and 0.95, per 1000 person-year, respectively). However, overall risk of glaucoma was not significantly higher in the late eradication than in the early eradication (adjusted hazard ratio = 0.85, 95% confidence interval = 0.48-1.53). The POAG incidence was greater in the late H pylori eradication cohort when follow-up duration ≤ 5 years (1.59, per 1000 person-years). However, when follow-up duration >5 years, the incidence of POAG was greater in the early H pylori eradication cohort (1.68, per 1000 person-years). These relationships were not associated with a significantly increased or decreased risk of POAG in multivariable analyses. Either early or late H pylori eradication does not significantly reduce the risk of glaucoma in patients with peptic ulcer disease compared with normal control.

Amyloid β Peptides and Cognitive Functions in Patients with Pseudoexfoliation Syndrome

PURPOSE

The aim of this study was to evaluate if there is any relation between the Alzheimer's peptides (amyloid β-40 and β-42) concentration in plasma and aqueous humor as well as cognitive functions with pseudoexfoliation syndrome (PEX).

METHODS

One-hundred forty-two patients with PEX have been included for this study; median age: 75 years (Q1 = 71,5; Q3 = 80,0). Control group comprised 93 subjects aged 74 years (Q1 = 68,0; Q3 = 80,0). Amyloid β-40 and β-42 (Aβ-40, Aβ-42) concentrations were assessed in plasma in 73 PEX patients and 49 controls. Aβ-40 concentration in aqueous humor was measured in 31 patients from each group. Mini Mental State Examination (MMSE) and Clock Drawing Tests were performed in 83 PEX patients and 36 controls.

RESULTS

The differences between amyloid concentrations both in plasma and in aqueous humor in PEX and control groups were not statistically significant. There were no differences in MMSE and Clock Drawing Tests between groups.

CONCLUSION

Our results do not indicate any relation between PEX and Alzheimer's amyloids or cognitive functions in cataract patients.

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.

Helicobacter pylori infection, dementia and primary open-angle glaucoma: are they connected?

Background

The study aims to elucidate the putative association between various forms of dementia, including Alzheimer’s disease, primary open-angle glaucoma and Helicobacter pylori (H.pylori) infection in all possible combinations.

Methods

We prospectively recruited for the study 156 patients, divided into a dementia group, a glaucoma group and two control groups. All patients were submitted to neuropsychological evaluation aiming to detect dementia, ophthalmological examination, aiming to detect glaucoma, and H.pylori diagnostic testing. The provided data were analyzed with the question of possible correlation between the aforementioned entities.

Results

Positive correlations were found between Hp infection and dementia, Hp infection and glaucoma, as well as between dementia and glaucoma.

Conclusions

The study confirmed the hypothesis that neurodegenerative diseases such as dementia and glaucoma are linked to each other and to H.pylori infection.

Helicobacter pylori infection and eye diseases: a systematic review

The connection between Helicobacter pylori (Hp) infection and eye diseases has been increasingly reported in the literature and in active research. The implication of this bacterium in chronic eye diseases, such as blepharitis, glaucoma, central serous chorioretinopathy and others, has been hypothesized. Although the mechanisms by which this association occurs are currently unknown, this review describes shared pathogenetic mechanisms in an attempt to identify a lowest common denominator between eye diseases and Hp infection. The aim of this review is to assess whether different studies could be compared and to establish whether or not Hp infection and Eye diseases share common pathogenetic aspects. In particular, it has been focused on oxidative damage as a possible link between these pathologies. Text word search in Medline from 1998 to July 2014. 152 studies were included in our review. Were taken into considerations only studies that related eye diseases more frequent and/or known. Likely oxidative stress plays a key role. All of the diseases studied seem to follow a common pattern that implicates a cellular response correlated with a sublethal dose of oxidative stress. These alterations seem to be shared by both Hp infections and ocular diseases and include the following: decline in mitochondrial function, increases in the rate of reactive oxygen species production, accumulation of mitochondrial DNA mutations, increases in the levels of oxidative damage to DNA, proteins and lipids, and decreases in the capacity to degrade oxidatively damaged proteins and other macromolecules. This cascade of events appears to repeat itself in different diseases, regardless of the identity of the affected tissue. The trabecular meshwork, conjunctiva, and retina can each show how oxidative stress may acts as a common disease effector as the Helicobacter infection spreads, supported by the increased oxidative damage and other inflammation.

Association between helicobacter pylori infection and primary open angle glaucoma

Aim:

To compare the prevalence of Pylori infection in patients with primary open angle glaucoma (POAG) and control group with cataract.

Methods:

This is a prospective case-control study. The participants were organized in two groups. First group (case) consisted of 35 patients with POAG and second group consisted of 35 age matched participants with cataract whose optic disk could be evaluated. Serum levels of anti H. pylori IgG antibody were evaluated with the method of ELISA.

Results:

The seroprevalence of Pylori infection was 89.1 % (33 of 37) in patients with POAG and 59.5 % (25 of 42) in the control group. The difference was significant (P=0.008). The odds ratio for association between Pylori and POAG was 5.69 and the range of 95% confidence interval was from 1.58 to 20.50.

Conclusion:

This study suggests that Helicobacter Pylori infection might be associated with primary open angle glaucoma.

A proposed role of human defensins in Helicobacter pylori-related neurodegenerative disorders

Cationic host defence peptides (CHDPs), also known as antimicrobial peptides (AMPs), are essential components of the innate immunity with antimicrobial and pleiotropic immunomodulatory properties. In mammals the two major families of CHDPs are defensins and cathelicidins that comprise an arsenal of innate regulators of principal importance in the host tissues. Research in the last decade has demonstrated that defensins are crucial effectors of both innate and adaptive immunity. Defensins can modulate immune responses, either by stimulation or suppression, thereby controlling inflammatory processes and infections. Currently only few data, mostly hypothetical, focus on the role of defensins in central nervous system (CNS) physiopathology and neurodegeneration. Defensins may function as an initial line of defense within the CNS either as an antimicrobial, immunomodulator, or both. A dysregulation of brain expression of specific defensins might either exacerbate or ameliorate the inflammatory response within the CNS depending upon which extracellular conditions predominate. It is proposed that reduction or abnormal elevation of AMP expression by cerebral microglia, astrocytes or choroid plexus epithelium might contribute to loss of AMP-induced regulation of immune responses, thereby promoting neuronal cell injury and death observed in Alzheimer's disease and possibly in other neurodegenerative disorders. Nevertheless, whether certain AMPs play a crucial role in the onset or promotion of the neuroinflammatory process and neurodegeneration is currently unknown, thereby emphasizing the necessity of further investigation into the regulatory mechanisms that control innate and adaptive immunity within the brain. Recent data indicate that Helicobacter pylori (H. pylori) induces defensins' release associated with chronic inflammatory tissue damage. However, it remains unclear whether and how H. pylori evades the attack by defensins. Moreover, recent evidence indicates that H. pylori infection might contribute to the pathogenesis of neurodegenerative diseases, by releasing several inflammatory mediators that could induce blood-brain barrier breakdown, thereby being involved in the pathogenesis of neurodegeneration. However, currently there are no data regarding the potential impact of human defensins on H. pylori-related neurodegenerative disorders. We herein propose that human defensins might contribute to the pathophysiology of H. pylori-related neurodegenerative disorders by modulating variably innate and adaptive immune system responses. Better understanding of the mechanisms regarding human defensins' possible involvement in H. pylori-induced neurodegeneration might help develop novel therapeutic strategies against H. pylori-related neurodegenerative disorders.

The role of Helicobacter pylori infection in hematological disorders

Helicobacter pylori (H. pylori) is a Gram-negative spiral bacterium, classified as a carcinogen of class I, according to the World Health Organization (WHO). The infection is a major cause of gastritis, gastric and duodenal ulcer disease and increases the risk of gastric cancer. It has been implicated in the pathogenesis of several gastrointestinal, systemic or hematological diseases. The present review aims in deciphering the role of the bacterium in hematological disorders, increasing the awareness of gastroenterologists, hematologists and internal medicine practitioners, regarding the bacterium-associated hematological diseases. The efficacy of H. pylori eradication in increasing the platelet count in adult patients with primary immune thrombocytopenia (ITP) has been confirmed, linking the infection with the disease. Moreover, as the bacterium causes iron deficiency anemia (IDA) by several mechanisms, recent guidelines indicate H. pylori infection (Hp-I) to be sought in IDA patients if histology is negative and to be eradicated if present. Furthermore, it has been widely recognized that anti-H. pylori treatment causes regression of the low-grade B-cell gastric MALT lymphomas. Despite the well established associations of Hp-I with the aforementioned hematological disorders, we highlight the possible role of the infection to other hematological diseases or conditions such as non-Hodgkin lymphomas of the stomach, monoclonal gammopathy of undetermined significance, megaloblastic anemia and myelodysplastic syndromes. We finally underline the elevated risk of childhood leukemia and of hemorrhage in patients with coagulation disorders, due to the infection.

The effects of Helicobacter pylori infection on intraocular pressure in anterior uveitis

PURPOSE

We investigated the influence of H. pylori infection on intraocular pressure (IOP) in anterior uveitis patients to clarify whether H. pylori infection is related to high IOP in anterior uveitis.

METHODS

In this prospective study, 165 Korean anterior uveitis patients were examined. All patients underwent serological analysis to identify the cause of uveitis, including the presence of H. pylori infection by enzyme-linked immunosorbent assay. Serological values were compared between patients with and without high IOP.

RESULTS

Seropositivity for H. pylori was 69.70% of patients with high IOP and 38.38% of patients with normal IOP (P<0.01).

CONCLUSION

This study suggests that H. pylori infection is associated with high IOP in anterior uveitis.

Helicobacter pylori infection and primary open-angle glaucoma: is there a connection?

Glaucoma, the most common form of which is primary open-angle glaucoma (POAG), is a neurodegenerative disease which is the second most common cause of blindness worldwide. Among the factors that have been implicated in the pathophysiology of this disease is infection with Helicobacter pylori. This alleged association has caused a great deal of scientific discussion during the past decade, as the establishment of such a correlation might lead to therapeutic applications for all glaucoma patients. In this review, we assess all relevant major studies and trials in an effort to elucidate the issue.

Glaucoma and Alzheimer’s disease in the elderly

Primary open angle glaucoma and Alzheimer’s disease have long been established as two separate pathological entities, primarily affecting the elderly. The progressive, irreversible course of both diseases has significant implications on an aging population. As the complex pathophysiology of the two diseases has progressively unraveled over the past two decades, common pathophysiological changes have also been elucidated. Some of these mechanisms have established a strong grounding, whilst others remain principally speculative. The mutual neuropathological changes in primary open angle glaucoma and Alzheimer’s disease have facilitated the development of neuroprotective strategies. While most of these strategies are still in the preclinical phase, they have shown great promise in experimental animal studies. Further understanding of the common pathophysiology of primary open angle glaucoma and Alzheimer’s disease and their timeline may have great implications on early diagnosis and effective therapeutic targeting.