Single nucleotide polymorphisms related to vitamin B12 serum levels in autoimmune gastritis patients with or without pernicious anaemia

The Importance of Nutrigenetics and Microbiota in Personalized Medicine: From Phenotype to Genotype

Background After the completion of the Human Genome Project in 2003, the impact of genetic variations among people on human health was better understood. Precision medicine, also called 4P (Predictive, Preventive, Personalized, Participatory) medicine, is used to determine personal health risks, prevent, diagnose, and treat chronic diseases, and aims to identify the phenotypic, genotypic, and environmental factors that affect individual health risks instead of applying the same approach to everyone. Methods The study was conducted with 24 patients aged between 7 and 57. The patient group was selected from individuals who had undergone genetic and microbiota testing at Epigenetic Coaching Company. The patients' age, gender, and health status were documented. Genomic analysis of buccal samples was subsequently conducted using a custom Infinium HTS iSelect microarray on an Illumina iScan instrument, and microbiota metagenome analysis was performed using an Illumina NextSeq 500 platform. This study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the Ethics Committee of Biruni University Molecular Biology and Genetics Ethics Committee, with the decision number 2023/78-03. Results The genotypes of 19 cases carrying genetic variants involved in the metabolism of Vitamin D, Folate, B12, and Choline were analyzed. Eight of the cases were included in our study as autism patients, eight as allergy patients, and three as autoimmune thyroiditis patients. The Vitamin D receptor (VDR) genetic variants and microbiota diversity (using the Firmicutes/Bacteroides ratio, an indicator of dysbiosis) of 11 cases (9 allergy and two autism patients) participating in the study were evaluated together. Conclusions Translating nutrigenetic and nutrigenomic research into multidisciplinary clinical practice is the most challenging aspect. It is now evident that integrating data regarding phenotype and genotype, and using nutrition, lifestyle, and supplements tailored to an individual's genetics can increase clinical success. Importantly, if we wish to adopt an epigenomic approach, we must incorporate analyses of nutrigenetics, microbiota, and personalized risk based on test results.

Clinical relevance of vitamin B12 level and vitamin B12 metabolic gene variation in pulmonary tuberculosis

The aim of this study was to assess the association of vitamin B12 level and single nucleotide polymorphisms (SNPs) in vitamin B12 metabolic genes with pulmonary tuberculosis (PTB) in Chinese Han population. The plasma vitamin B12 expression level was detected using ELISA. Ten SNPs in six key genes (TCN1, TCN2, CUBN, MMACHC, FUT6, and MUT) of vitamin B12 metabolic pathway were included for genotyping by the SNPscan technique among 454 PTB patients and 467 controls. Our results found that vitamin B12 level was significantly reduced in PTB patients when compared with controls. There was no significant association between TCN1 rs526934, TCN2 rs1801198, CUBN rs7906242, rs10904861, rs1801222, MMACHC rs10789465, FUT6 rs3760776, rs3760775, MUT rs9473555, rs9381784 variants, and PTB susceptibility. TCN2 rs1801198 CC genotype, C allele was significantly associated with hypoproteinemia in PTB patients. In CUBN, rs7906242 GG genotype, G allele, rs10904861 TT genotype, and T allele were significantly related to the decreased frequency of sputum smear-positive, and rs10904861 variant affected the occurrence of drug resistance in PTB patients. In addition, the increased frequency of CUBN rs1801222 AA genotype was significantly associated with leukopenia. The decreased frequency of MUT rs9473555 CC genotype was found in the PTB patients with hypoproteinemia. However, vitamin B12 expression was not associated with the genotype distribution of above SNPs. In conclusion, vitamin B12 level was significantly decreased in PTB patients and genetic variants in vitamin B12 metabolic genes were not contributed to PTB susceptibility. Several SNPs in TCN2, CUBN, and MUT gene might associate with multiple clinical manifestations in PTB.

Pernicious Anemia: The Hematological Presentation of a Multifaceted Disorder Caused by Cobalamin Deficiency

Pernicious anemia is still a neglected disorder in many medical contexts and is underdiagnosed in many patients. Pernicious anemia is linked to but different from autoimmune gastritis. Pernicious anemia occurs in a later stage of autoimmune atrophic gastritis when gastric intrinsic factor deficiency and consequent vitamin B₁₂ deficiency may occur. The multifaceted nature of pernicious anemia is related to the important role of cobalamin, which, when deficient, may lead to several dysfunctions, and thus, the proteiform clinical presentations of pernicious anemia. Indeed, pernicious anemia may lead to potentially serious long-term complications related to micronutrient deficiencies and their consequences and the development of gastric cancer and type 1 gastric neuroendocrine tumors. When not recognized in a timely manner or when pernicious anemia is diagnosed with delay, these complications may be potentially life-threatening and sometimes irreversible. The current review aimed to focus on epidemiology, pathogenesis, and clinical presentations of pernicious anemia in an attempt to look beyond borders of medical specialties. It aimed to focus on micronutrient deficiencies besides the well-known vitamin B₁₂ deficiency, the diagnostic approach for pernicious anemia, its long-term complications and optimal clinical management, and endoscopic surveillance of patients with pernicious anemia.

Rola autoimmunizacji w rozwoju powikłań cukrzycowych – przegląd badań

Przewlekłe powikłania cukrzycy są główną przyczyną obniżenia jakości życia, niepełnosprawności, a nawet przedwczesnej śmierci pacjentów cierpiących na tę chorobę. Mimo istotnego postępu w dziedzinie farmakoterapii, ich leczenie pozostaje nadal wyzwaniem w codziennej praktyce klinicznej. Brak terapii przyczynowej wynika z niewystarczającego zrozumienia molekularnych mechanizmów uszkadzających poszczególne narządy w cukrzycy. Uważa się, że etiopatogeneza tych powikłań jest złożona i zależy od czynników genetycznych i środowiskowych. W ich rozwoju, oprócz zaburzeń metabolicznych związanych z hiperglikemią, nasilenia stresu oksydacyjnego, dysfunkcji śródbłonka, indukcji stanu zapalnego, coraz częściej wskazuje się też na znaczącą rolę zaburzeń immunologicznych.

Wyniki badań doświadczalnych przeprowadzonych na zwierzętach, jak również na hodowlach tkankowych, oraz obserwacje kliniczne potwierdzają udział układu odpornościowego obejmujący aktywność autoreaktywnych limfocytów oraz cytotoksyczne działanie autoprzeciwciał w rozwoju poszczególnych powikłań w obu typach cukrzycy. Wydaje się zatem, że zachwianie równowagi immunologicznej wyzwalające autoagresję jest ważnym czynnikiem przyczyniającym się do dysfunkcji poszczególnych organów w typach cukrzycy 1 i 2.

Dokładne zrozumienie immunopatogenezy tych zaburzeń może zmienić dotychczasowe podejście w leczeniu powikłań cukrzycy oraz umożliwić opracowanie skutecznej terapii przyczynowej ukierunkowanej na układ odpornościowy. Identyfikacja swoistych autoprzeciwciał mogłaby usprawnić ich wczesną diagnostykę i prewencję. W artykule podjęto próbę analizy czynników ryzyka najczęstszych schorzeń o podłożu autoimmunizacyjnym, ich związku z typem 1 i 2 cukrzycy oraz podsumowano potencjalne znaczenie autoagresji w rozwoju jej powikłań w oparciu o wyniki dotychczasowych badań doświadczalnych i klinicznych.

Autoantibodies Toward ATP4A and ATP4B Subunits of Gastric Proton Pump H+,K+-ATPase Are Reliable Serological Pre-endoscopic Markers of Corpus Atrophic Gastritis

INTRODUCTION

Noninvasive assessment of corpus atrophic gastritis (CAG), a condition at increased risk of gastric cancer, is based on the measurement of pepsinogens, gastrin, and Helicobacter pylori antibodies. Parietal cell autoantibodies (PCAs) against the gastric proton pump (ATP4) are potential serological biomarkers of CAG. The purpose of this study was to compare the diagnostic performance of PCA and pepsinogen I tests in patients with clinical suspicion of CAG with the histopathological evaluation of gastric biopsies as reference standard.

METHODS

A prospective case-finding study was performed on 218 naive adult patients (131 women, median age 65 years) who underwent gastric biopsies to confirm/exclude CAG. Patients with histopathological CAG were defined as cases, conversely as controls. Autoantibodies against the individual alpha (ATP4A) and beta (ATP4B) subunits of ATP4 were measured by luciferase immunoprecipitation, and global PCA and pepsinogen I by enzyme-linked immunosorbent assay.

RESULTS

Histopathology classified 107 subjects (49%) as cases (CAG+, autoimmune 81.2%, and multifocal extensive 18.8%) and 111 subjects (51%) as controls (CAG-). In cases, ATP4A, ATP4B, and PCA titers were increased compared with controls, whereas pepsinogen I was reduced (P < 0.0001 for all). ATP4B, ATP4A, and pepsinogen I tests showed sensitivities of 77%, 75%, and 73% and specificities of 88%, 88%, and 80%, respectively. The receiver operating characteristic (ROC) area under the ROC curve (AUC) of these serological biomarkers confirmed their ability to discriminate cases from controls (ATP4B = 0.838, ATP4A = 0.826, pepsinogen I = 0.775, and PCA = 0.805), whereas the partial ROC-pAUC90 analysis showed that the ATP4B test had the best diagnostic performance (P = 0.008 vs ATP4; P = 0.0002 vs pepsinogen I). The presence of autoimmune or extensive gastritis was not significantly different between ATP4B positive or negative cases (P = 0.217).

DISCUSSION

PCAs are promising serological biomarkers for the identification of CAG in high-risk individuals, particularly in an autoimmune pattern but also in an extensive-multifocal atrophy pattern.

Thyro-entero-gastric autoimmunity: Pathophysiology and implications for patient management

The association between autoimmune atrophic gastritis and thyroid disorders has been observed since the early 1960s and the expression "thyrogastric syndrome" was coined to indicate the presence of thyroid autoantibodies or autoimmune thyroid disease in patients with pernicious anemia, a late clinical stage of autoimmune atrophic gastritis. More recently, it was confirmed that autoimmune thyroid disorders, in particular Hashimoto's thyroiditis, may be frequently associated with other organ-specific, immune-mediated disorders, such as autoimmune atrophic gastritis or celiac disease. The association of Hashimoto's thyroiditis with autoimmune atrophic gastritis or celiac disease in adult patients is currently considered part of the polyglandular autoimmune syndromes which include several autoimmune disorders associated with an autoaggressive impairment of endocrine glands. From a clinical point of view, the thyro-entero-gastric autoimmunity may lead to potentially serious consequences like anemia, micronutrients deficiencies, and drugs malabsorption, as well as to an increased risk for malignancies. These alterations may frequently present in an underhand manner, with consequent diagnostic and treatment delays. Many aspects of the association between thyroid, gastric and intestinal autoimmune diseases still await clarification. The present review focuses on the embryological, genetic and pathophysiological aspects of thyro-entero-gastric autoimmunity. In particular, the current diagnostic criteria of autoimmune thyroid disease, autoimmune atrophic gastritis, and celiac disease are reviewed, along with the evidences for their association in poly-autoimmunity syndromes. The benefits of proactive screening of autoimmune thyroid disorders in patients with autoimmune gastritis or enteropathy and viceversa are also discussed.

Cell Blood Count Alterations and Patterns of Anaemia in Autoimmune Atrophic Gastritis at Diagnosis: A Multicentre Study

BACKGROUND

Autoimmune atrophic gastritis (AAG) leads to iron and/or vitamin B12 malabsorption, with subsequent haematological alterations which could represent the sole clinical manifestation. We aimed to assess patterns of anaemia and micronutrient deficiencies in patients with AAG at the time of diagnosis.

METHODS

Observational, multicentre, cross-sectional study including consecutive adult patients diagnosed with AAG within the last ten years. Cell blood count, red cell distribution width, serum vitamin B12, and ferritin were collected. Multivariate analysis for predictive factors of anaemia was computed.

RESULTS

654 AAG patients (mean age 59.2 ± 13.8 years, female (F): male (M) ratio = 2.3:1) were included. Anaemia was present in 316 patients (48.3%; mean age 60.1 ± 15.8 years, F:M ratio = 2.3:1). Pernicious anaemia (132/316 cases, 41.7%) was more common in males (27.1% versus 12.4%; p = 0.001) and in older patients (63.0 ± 14.6 versus 58.9 ± 14.9 years; p = 0.014), while iron deficiency anaemia (112/316 cases, 35.4%) was more common in females (16.9% versus 10.0%; p = 0.039) and in younger patients (56.8 ± 16.6 versus 60.2 ± 14.6 years; p = 0.043). The prevalence of iron deficiency was equally distributed between anaemic and non-anaemic patients (p = 0.9). Anisocytosis (odds ratio: 10.65, 95% confidence interval: 6.13-18.50, p < 0.0001) was independently associated with anaemia.

CONCLUSIONS

Anaemia is a common manifestation in AAG patients, mostly due to micronutrient deficiencies. Scant haematologic alterations and micronutrient deficiencies may precede overt anaemia.

GutSelf: Interindividual Variability in the Processing of Dietary Compounds by the Human Gastrointestinal Tract

Nutritional research is currently entering the field of personalized nutrition, to a large extent driven by major technological breakthroughs in analytical sciences and biocomputing. An efficient launching of the personalized approach depends on the ability of researchers to comprehensively monitor and characterize interindividual variability in the activity of the human gastrointestinal tract. This information is currently not available in such a form. This review therefore aims at identifying and discussing published data, providing evidence on interindividual variability in the processing of the major nutrients, i.e., protein, fat, carbohydrates, vitamins, and minerals, along the gastrointestinal tract, including oral processing, intestinal digestion, and absorption. Although interindividual variability is not a primary endpoint of most studies identified, a significant number of publications provides a wealth of information on this topic for each category of nutrients. This knowledge remains fragmented, however, and understanding the clinical relevance of most of the interindividual responses to food ingestion described in this review remains unclear. In that regard, this review has identified a gap and sets the base for future research addressing the issue of the interindividual variability in the response of the human organism to the ingestion of foods.

Clinical manifestations of chronic atrophic gastritis

Although the actual prevalence of chronic atrophic gastritis is unknown and it is probable that this entity goes largely underdiagnosed, patients in whom diagnosis is established usually present advanced stages of disease. Destruction of parietal cells, either autoimmune-driven or as a consequence of Helicobacter pylori infection, determines reduction or abolition of acid secretion. Hypo/achloridia causes an increase in serum gastrin levels, with an increased risk of the development of neuroendocrine tumors. Microcytic, hypochromic anemia frequently precedes the development of megaloblastic, vitamin B12-associated anemia. Moreover, vitamin B12 deficiency,may cause elevation of homocysteine, with an increase in the cardiovascular risk, and may be associated with neurological manifestations, mainly characterized by spinal cord demyelination and atrophy, with ensuing sensory-motor abnormalities. Gastrointestinal manifestations seem to be associated with non-acid reflux and tend to be non-specific.

Correlation between serum vitamin B12 level and peripheral neuropathy in atrophic gastritis

AIM

To explore the correlation between serum vitamin B12 level and peripheral neuropathy in patients with chronic atrophic gastritis (CAG).

METHODS

A total of 593 patients diagnosed with chronic gastritis by gastroscopy and pathological examination from September 2013 to September 2016 were selected for this study. The age of these patients ranged within 18- to 75-years-old. Blood pressure, height and weight were measured in each patient, and the body mass index value was calculated. Furthermore, gastric acid, serum gastrin, serum vitamin and serum creatinine tests were performed, and peripheral nerve conduction velocity and Helicobacter pylori (H. pylori) were detected. In addition, the type of gastritis was determined by gastroscopy. The above factors were used as independent variables to analyze chronic gastritis with peripheral neuropathy and vitamin B12 deficiency risk factors, and to analyze the relationship between vitamin B12 levels and peripheral nerve conduction velocity. In addition, in the treatment of CAG on the basis of vitamin B12, patients with peripheral neuropathy were observed.

RESULTS

Age, H. pylori infection, CAG, vitamin B9 and vitamin B12 were risk factors for the occurrence of peripheral nerve degeneration. Furthermore, CAG and H. pylori infection were risk factors for chronic gastritis associated with vitamin B12 deficiency. Serum vitamin B12 level was positively correlated with sensory nerve conduction velocity in the tibial nerve (R = 0.463). After vitamin B12 supplementation, patients with peripheral neuropathy improved.

CONCLUSION

Serum vitamin B12 levels in patients with chronic gastritis significantly decreased, and the occurrence of peripheral neuropathy had a certain correlation. CAG and H. pylori infection are risk factors for vitamin B12 deficiency and peripheral neuropathy. When treating CAG, vitamin B12 supplementation can significantly reduce peripheral nervous system lesions. Therefore, the occurrence of peripheral neuropathy associated with vitamin B12 deficiency may be considered in patients with CAG. Furthermore, the timely supplementation of vitamin B12 during the clinical treatment of CAG can reduce or prevent peripheral nervous system lesions.

An update on vitamin B12-related gene polymorphisms and B12 status

Background

Vitamin B12 is an essential micronutrient in humans needed for health maintenance. Deficiency of vitamin B12 has been linked to dietary, environmental and genetic factors. Evidence for the genetic basis of vitamin B12 status is poorly understood. However, advancements in genomic techniques have increased the knowledge-base of the genetics of vitamin B12 status. Based on the candidate gene and genome-wide association (GWA) studies, associations between genetic loci in several genes involved in vitamin B12 metabolism have been identified.

Objective

The objective of this literature review was to identify and discuss reports of associations between single-nucleotide polymorphisms (SNPs) in vitamin B12 pathway genes and their influence on the circulating levels of vitamin B12.

Methods

Relevant articles were obtained through a literature search on PubMed through to May 2017. An article was included if it examined an association of a SNP with serum or plasma vitamin B12 concentration. Beta coefficients and odds ratios were used to describe the strength of an association, and a P < 0.05 was considered as statistically significant. Two reviewers independently evaluated the eligibility for the inclusion criteria and extracted the data.

Results

From 23 studies which fulfilled the selection criteria, 16 studies identified SNPs that showed statistically significant associations with vitamin B12 concentrations. Fifty-nine vitamin B12-related gene polymorphisms associated with vitamin B12 status were identified in total, from the following populations: African American, Brazilian, Canadian, Chinese, Danish, English, European ancestry, Icelandic, Indian, Italian, Latino, Northern Irish, Portuguese and residents of the USA.

Conclusion

Overall, the data analyzed suggests that ethnic-specific associations are involved in the genetic determination of vitamin B12 concentrations. However, despite recent success in genetic studies, the majority of identified genes that could explain variation in vitamin B12 concentrations were from Caucasian populations. Further research utilizing larger sample sizes of non-Caucasian populations is necessary in order to better understand these ethnic-specific associations.

Micronutrient deficiencies in patients with chronic atrophic autoimmune gastritis: A review

Chronic atrophic autoimmune gastritis (CAAG) is an organ-specific autoimmune disease characterized by an immune response, which is directed towards the parietal cells and intrinsic factor of the gastric body and fundus and leads to hypochlorhydria, hypergastrinemia and inadequate production of the intrinsic factor. As a result, the stomach’s secretion of essential substances, such as hydrochloric acid and intrinsic factor, is reduced, leading to digestive impairments. The most common is vitamin B12 deficiency, which results in a megaloblastic anemia and iron malabsorption, leading to iron deficiency anemia. However, in the last years the deficiency of several other vitamins and micronutrients, such as vitamin C, vitamin D, folic acid and calcium, has been increasingly described in patients with CAAG. In addition the occurrence of multiple vitamin deficiencies may lead to severe hematological, neurological and skeletal manifestations in CAAG patients and highlights the importance of an integrated evaluation of these patients. Nevertheless, the nutritional deficiencies in CAAG are largely understudied. We have investigated the frequency and associated features of nutritional deficiencies in CAAG in order to focus on any deficit that may be clinically significant, but relatively easy to correct. This descriptive review updates and summarizes the literature on different nutrient deficiencies in CAAG in order to optimize the treatment and the follow-up of patients affected with CAAG.

Luminescent Immunoprecipitation System (LIPS) for Detection of Autoantibodies Against ATP4A and ATP4B Subunits of Gastric Proton Pump H+,K+-ATPase in Atrophic Body Gastritis Patients

OBJECTIVES

Circulating autoantibodies targeting the H+/K+-ATPase proton pump of gastric parietal cells are considered markers of autoimmune gastritis, whose diagnostic accuracy in atrophic body gastritis, the pathological lesion of autoimmune gastritis, remains unknown. This study aimed to assess autoantibodies against ATP4A and ATP4B subunits of parietal cells H+, K+-ATPase in atrophic body gastritis patients and controls.

METHODS

One-hundred and four cases with atrophic body gastritis and 205 controls were assessed for serological autoantibodies specific for ATP4A or ATP4B subunits using luminescent immunoprecipitation system (LIPS). Recombinant luciferase-reporter-fused-antigens were expressed by in vitro transcription-translation (ATP4A) or after transfection in Expi293F cells (ATP4B), incubated with test sera, and immune complexes recovered using protein-A-sepharose. LIPS assays were compared with a commercial enzyme immunoassay (EIA) for parietal cell autoantibodies.

RESULTS

ATP4A and ATP4B autoantibody titers were higher in cases compared to controls (P<0.0001). The area under the receiver-operating characteristic curve was 0.98 (95% CI 0.965-0.996) for ATP4A, and 0.99 (95% CI 0.979-1.000) for ATP4B, both higher as compared with that of EIA: 0.86 (95% CI 0.809-0.896), P<0.0001. Sensitivity-specificity were 100-89% for ATP4A and 100-90% for ATP4B assay. Compared with LIPS, EIA for parietal cell autoantibodies showed a lower sensitivity (72%, P<0.0001) at a similar specificity (92%, P=0.558).

CONCLUSIONS

Positivity to both, ATP4A and ATP4B autoantibodies is closely associated with atrophic body gastritis. Both assays had the highest sensitivity, at the cost of diagnostic accuracy (89 and 90% specificity), outperforming traditional EIA. Once validated, these LIPS assays should be valuable screening tools for detecting biomarkers of damaged atrophic oxyntic mucosa.

Upper gastrointestinal symptoms in autoimmune gastritis: A cross-sectional study

Autoimmune gastritis is often suspected for its hematologic findings, and rarely the diagnosis is made for the presence of gastrointestinal symptoms. Aims of this cross-sectional study were to assess in a large cohort of patients affected by autoimmune gastritis the occurrence and the pattern of gastrointestinal symptoms and to evaluate whether symptomatic patients are characterized by specific clinical features.Gastrointestinal symptoms of 379 consecutive autoimmune gastritis patients were systematically assessed and classified following Rome III Criteria. Association between symptoms and anemia pattern, positivity to gastric autoantibodies, Helicobacter pylori infection, and concomitant autoimmune disease were evaluated.In total, 70.2% of patients were female, median age 55 years (range 17-83). Pernicious anemia (53.6%), iron deficiency anemia (34.8%), gastric autoantibodies (68.8%), and autoimmune disorders (41.7%) were present. However, 56.7% of patients complained of gastrointestinal symptoms, 69.8% of them had exclusively upper symptoms, 15.8% only lower and 14.4% concomitant upper and lower symptoms. Dyspepsia, subtype postprandial distress syndrome was the most represented, being present in 60.2% of symptomatic patients. Univariate and multivariate analyses showed that age <55 years (OR 1.6 [CI:1-2.5]), absence of smoking habit (OR 2.2 [CI:1.2-4]), and absence of anemia (OR 3.1 [CI:1.5-6.4]) were independent factors associated to dyspepsia.Autoimmune gastritis is associated in almost 60% of cases with gastrointestinal symptoms, in particular dyspepsia. Dyspepsia is strictly related to younger age, no smoking, and absence of anemia.