Historical review: a history of pernicious anaemia

Quality of Life of Complete Denture Wearers-A Comparative Study between Conventional Dentures and Acrylic Dentures with Vitamin B12 Incorporated

Background and objectives: This paper is a sequel to the studies that focused on the optimization of the structure of classical acrylates with vitamin B12 as a template and their impact on patients’ general and local health. In this context, we aim to investigate the relationships between attitudes and behavior regarding oral health, oral health status, and quality of life related to oral health in the case of patients with conventional dentures and those with dentures improved with vitamin B12. Material and Methods: The sample size was estimated from previous studies, and 252 participants were enrolled and divided into two groups, one of which received as a treatment complete dentures with B12, and the other group was represented by complete edentulous patients treated with conventional complete dentures. The impact of oral health in general on patient satisfaction and quality of life was assessed using Oral Health Impact Profile OHIP-14 questionnaires. The descriptive statistical analysis was performed using SPSS 20.0. A value of p < 0.05 was considered statistically significant. Results: Differences registered between the two groups were statistically significant in all evaluated dimensions. The largest differences were recorded for physical, psychological, and social disability as well as for the level of disability, all in favor of denture B12 wearers. Conclusions: The materials used in the treatment of complete edentation can be a future research direction that can not only improve their mechanical strength but can contribute to maintaining the superior health of the oral mucosa and can also be a way of transporting substances necessary for the normal development of the metabolism of the whole body, such as vitamin B12 in our case.

Reduced levels of serum vitamin B12 in symptomatic cases of oral lichen planus: A cross-sectional study

Objectives

Oral Lichen Planus (OLP) is an immune mediated disease and causes oro-mucosal burning sensation that reduces food intake and hence resulting in nutritional deficiency. The present study was done to evaluate the serum levels of vitamin B12 in patients with symptomatic OLP and establish an association between reduced B12 levels and OLP.

Materials and method

Serum vitamin B12 was assessed in 60 symptomatic cases of oral lichen planus and 60 healthy age and gender matched controls.

Results

Serum vitamin B12 was significantly reduced (p value < 0) in patients with oral lichen planus when compared to healthy individuals. 43.33% of cases (26 out of 60) had B12 levels less than 187 pg/ml.

Conclusion

Oral lichen planus causes serum vitamin B12 deficiency. Vitamin B12 is linked with normal functioning of immune and neuropsychologic system which has a role to play in etiopathogenesis and malignant transformation of oral lichen planus.

Diabetes mellitus and pernicious anemia: interrelated therapeutic triumphs discovered shortly after William Osler's death

William Osler died on December 29, 1919, at the age of 70. Less than 1 year later, Frederick Grant Banting began a research project at the University of Toronto to find a treatment for diabetes mellitus. John James Rickard Macleod, director of physiology, gave him space, funding, and supplies. Charles Herbert Best, an undergraduate medical student, joined Banting. In 1921, Banting and Best isolated and purified insulin from pancreatic extracts of dogs. James Bertram Collip, a biochemist, helped in the purification process. The first American patient was treated with Toronto insulin in May 1922. Banting and Macleod were awarded the Nobel Prize in 1923 "for the discovery of insulin." George Richards Minot, a young hematologist in Boston, had an obsessive interest in the effect of diet on anemia. In October 1921, Minot developed weight loss and was diagnosed with severe diabetes mellitus. By January 1923, the pioneering diabetologist, Elliott Proctor Joslin, began to treat Minot with insulin. Minot's condition improved and he returned to work. In 1926, Minot and William Parry Murphy amazed the medical world when they eradicated anemia in 45 pernicious anemia patients by feeding them a half-pound of beef liver daily. Minot shared the 1934 Nobel Prize with Murphy and George Hoyt Whipple "for their discoveries concerning liver therapy in cases of anemia." Minot remained on insulin the rest of his life. Osler described the clinical findings and blood picture of pernicious anemia nearly a half century before Minot but his observations were largely ignored. Osler had an intriguing connection to Banting. Had he lived, Osler would have been ecstatic over these two monumental therapeutic breakthroughs.

Lack of historical evidence to support folic acid exacerbation of the neuropathy caused by vitamin B12 deficiency

In 1998 a Tolerable Upper Intake Level (UL) for folic acid was established based on case reports from the 1940s suggesting that high-dosage folic acid intake, used to treat patients with pernicious anemia, had the potential to precipitate or speed-up the development of neurological problems. This UL has been employed in the decision-making process used by more than 80 countries to establish programs to fortify staple foods with folic acid to prevent neural tube birth defects. Some have claimed that this UL is flawed and has become an obstacle to the wider adoption of neural tube defect prevention programs and have called for re-evaluation of the scientific validity of this UL. Case reports cannot establish causality, but they can reveal patterns in the timing of the onset and treatment of patients with pernicious anemia. These patterns can be compared with secular trends of usual medical practice for the treatment of pernicious anemia and with the changes in usage of folic acid preparations, including recommended therapeutic dosage and precautions for its usage surrounding the synthesis of folic acid in 1945 and vitamin B12 in 1948. Folic acid package inserts, early editions of hematology textbooks, and international expert reports provide valuable historical information. The recommended therapeutic daily dosage for folic acid of 5-20 mg was unchanged from 1946 through to 1971. The likely cause of the neurological problems encountered is the development of vitamin B12 neuropathy when pernicious anemia was treated with high-dosage folic acid before vitamin B12 was widely available in the early 1950s. Thus, the historical record does not provide compelling evidence that folic acid can potentially cause neurologic complications among those with low vitamin B12 status and lends support for reconsidering the basis for the UL of folic acid.

Biomarkers of Nutrition for Development (BOND): Vitamin B-12 Review

This report on vitamin B-12 (B12) is part of the Biomarkers of Nutrition for Development (BOND) Project, which provides state-of-the art information and advice on the selection, use, and interpretation of biomarkers of nutrient exposure, status, and function. As with the other 5 reports in this series, which focused on iodine, folate, zinc, iron, and vitamin A, this B12 report was developed with the assistance of an expert panel (BOND B12 EP) and other experts who provided information during a consultation. The experts reviewed the existing literature in depth in order to consolidate existing relevant information on the biology of B12, including known and possible effects of insufficiency, and available and potential biomarkers of status. Unlike the situation for the other 5 nutrients reviewed during the BOND project, there has been relatively little previous attention paid to B12 status and its biomarkers, so this report is a landmark in terms of the consolidation and interpretation of the available information on B12 nutrition. Historically, most focus has been on diagnosis and treatment of clinical symptoms of B12 deficiency, which result primarily from pernicious anemia or strict vegetarianism. More recently, we have become aware of the high prevalence of B12 insufficiency in populations consuming low amounts of animal-source foods, which can be detected with ≥1 serum biomarker but presents the new challenge of identifying functional consequences that may require public health interventions.

Periconceptional intake of folic acid among low-risk women in Canada: summary of a workshop aiming to align prenatal folic acid supplement composition with current expert guidelines

The Government of Canada and the Society of Obstetricians and Gynaecologists of Canada both recommend a daily multivitamin supplement containing 400 µg folic acid (FA) for the primary prevention of neural tube defects among low-risk women from before conception and throughout lactation. Prenatal supplements marketed and prescribed in Canada typically exceed the recommended dose, usually providing ≥1000 µg FA/d. This high daily dose, coupled with staple-food FA fortification, has resulted in the observation of very high blood folate concentrations among reproductive-aged women consuming FA-containing supplements. The long-term consequences of high folate status on fetal development are unknown; however, evidence from animal studies and some human epidemiologic data suggest potential adverse consequences. To address this issue, a workshop was convened with the overall goal to identify challenges and solutions to aligning supplemental FA intakes with current evidence-based recommendations. Thirty-eight stakeholders from academia, industry, government, and health professional groups participated. Group discussions facilitated the identification and prioritization of 5 key challenges for which solutions and implementation strategies were proposed. The 5 themes encompassed clarity and harmonization of evidence-based guidelines, reformulation or relabeling of FA-containing supplements, access to FA for all women, knowledge dissemination strategies and education of the public and health care professionals, and attitude change to overcome the perception of "more is better." A combination of the proposed implementation strategies involving all key stakeholders and directed to health care professionals and the public may enable a sustainable change to align FA intake during the periconceptional period with evidence-based recommendations.

Vitamin B12 among Vegetarians: Status, Assessment and Supplementation

Cobalamin is an essential molecule for humans. It acts as a cofactor in one-carbon transfers through methylation and molecular rearrangement. These functions take place in fatty acid, amino acid and nucleic acid metabolic pathways. The deficiency of vitamin B12 is clinically manifested in the blood and nervous system where the cobalamin plays a key role in cell replication and in fatty acid metabolism. Hypovitaminosis arises from inadequate absorption, from genetic defects that alter transport through the body, or from inadequate intake as a result of diet. With the growing adoption of vegetarian eating styles in Western countries, there is growing focus on whether diets that exclude animal foods are adequate. Since food availability in these countries is not a problem, and therefore plant foods are sufficiently adequate, the most delicate issue remains the contribution of cobalamin, which is poorly represented in plants. In this review, we will discuss the status of vitamin B12 among vegetarians, the diagnostic markers for the detection of cobalamin deficiency and appropriate sources for sufficient intake, through the description of the features and functions of vitamin B12 and its absorption mechanism.

Feeding immunity: skepticism, delicacies and delights

Immunologists studying the relationship between nutrition and immunological function face many challenges. We discuss here some of the historical skepticism with which nutritional research has often been faced and the complexities that need to be overcome in order to provide meaningful mechanistic insights.

Learning about being a scientist from the vitamin B12 structure collaboration

This historical note reviews the work that resulted in the publication of the structure of Vitamin B12 . The collaborations and resulting friendships that developed during this time made a strong impression on the author and encouraged her to pursue a scientific career.

The prevalence of low serum vitamin B-12 status in the absence of anemia or macrocytosis did not increase among older U.S. adults after mandatory folic acid fortification

Whether folic acid fortification and supplementation at the population level have led to a higher prevalence of vitamin B-12 deficiency in the absence of anemia remains to be examined among a nationally representative sample of older U.S. adults. We assessed the prevalence of low vitamin B-12 status in the absence of anemia or macrocytosis before and after fortification among adults aged >50 y using cross-sectional data from the NHANES 1991-1994 (prefortification) and 2001-2006 (postfortification). We compared the prefortification and postfortification prevalence of multiple outcomes, including serum vitamin B-12 deficiency (<148 pmol/L) and marginal deficiency (148-258 pmol/L) with and without anemia (hemoglobin <130 g/L for men, <120 g/L for women) and with and without macrocytosis (mean cell volume >100 fL) using multinomial logistic regression, adjusting for age, sex, ethnicity, body mass index, C-reactive protein, and vitamin B-12 supplement use. Prefortification and postfortification serum vitamin B-12 deficiency without anemia [4.0 vs. 3.9%; adjusted prevalence ratio (aPR) (95% CI): 0.98 (0.67, 1.44)] or without macrocytosis [4.2 vs. 4.1%; aPR (95% CI): 0.96 (0.65, 1.43)] remained unchanged. Marginal deficiency without anemia [25.1 vs. 20.7%; aPR (95% CI): 0.82 (0.72, 0.95)] or without macrocytosis [25.9 vs. 21.3%; aPR (95% CI): 0.82 (0.72, 0.94)] were both significantly lower after fortification. After fortification, higher folic acid intake was associated with a lower prevalence of low serum B-12 status in the absence of anemia or macrocytosis. Results suggest that the prevalence of low serum B-12 status in the absence of anemia or macrocytosis among older U.S. adults did not increase after fortification. Thus, at the population level, we found no evidence to support concerns that folic acid adversely affected the clinical presentation of vitamin B-12 deficiency among older adults.

Neurologic aspects of cobalamin (B12) deficiency

Optimal functioning of the central and peripheral nervous system is dependent on a constant supply of appropriate nutrients. Particularly important for optimal functioning of the nervous system is cobalamin (vitamin B12). Cobalamin deficiency is particularly common in the elderly and after gastric surgery. Many patients with clinically expressed cobalamin deficiency have intrinsic factor-related malabsorption such as that seen in pernicious anemia. The commonly recognized neurological manifestations of cobalamin deficiency include a myelopathy with or without an associated neuropathy. This review deals with neurological aspects of vitamin B12 deficiency and attempts to highlight recent developments.

[History of the therapy of pernicious anemia]

Increased blood cell regeneration in exsanguinated experimental animals treated either with liver or with aqueous liver extracts was reported by Whipple and by Jeney and Jobling, respectively. These findings stimulated Minot and Murphy to provide evidence for the efficacy of liver against anaemia in clinical studies. After oral administration of liver (45-50 g per day) for 45 patients with anaemia perniciosa improvement of the hematological status was demonstrated. Consequently, for proving the therapeutic value of liver therapy Whipple, Minot and Murphy received Nobel price in 1934. The isolation of the antianemic factor from the liver has been succeeded in 1948 and designated as vitamin B12. At the same time Lucy Wills applied yeast for the treatment of pregnant women with anemia related to undernourishment. The conclusions of this study inspired the discovery of folate. The detailed investigation of the mode of action of vitamin B12 and folate enriched our knowledge in the area of pathophysiology and extended the clinical application of these two drugs.

Folate and B12 in prostate cancer

Mechanisms postulated to link folate and B12 metabolism with cancer, including genome-wide hypomethylation, gene-specific promoter hypermethylation, and DNA uracil misincorporation, have been observed in prostate tumor cells. However, epidemiological studies of prostate cancer risk, based on dietary intakes and blood levels of folate and vitamin B12 and on folate-pathway gene variants, have generated contradictory findings. In a meta-analysis, circulating concentrations of B12 (seven studies, OR = 1.10; 95% CI 1.01, 1.19; P = 0.002) and (in cohort studies) folate (five studies, OR = 1.18; 95% CI 1.00, 1.40; P = 0.02) were positively associated with an increased risk of prostate cancer. Homocysteine was not associated with risk of prostate cancer (four studies, OR = 0.91; 95% CI 0.69, 1.19; P = 0.5). In a meta-analysis of folate-pathway polymorphisms, MTR 2756A > G (eight studies, OR = 1.06; 95% CI 1.00, 1.12; P = 0.06) and SHMT1 1420C > T (two studies, OR = 1.11; 95% CI 1.00, 1.22; P = 0.05) were positively associated with prostate cancer risk. There were no effects due to any other polymorphisms, including MTHFR 677C > T (12 studies, OR = 1.04; 95% CI 0.97, 1.12; P = 0.3). The positive association of circulating B12 with an increased risk of prostate cancer could be explained by reverse causality. However, given current controversies over mandatory B12 fortification, further research to eliminate a causal role of B12 in prostate cancer initiation and/or progression is required. Meta-analysis does not entirely rule out a positive association of circulating folate with increased prostate cancer risk. As with B12, even a weak positive association would be a significant public health issue, given the high prevalence of prostate cancer and concerns about the potential harms versus benefits of mandatory folic acid fortification.

Cobalamin in companion animals: diagnostic marker, deficiency states and therapeutic implications

Measurement of the water-soluble vitamin cobalamin has long been of interest as a marker of gastrointestinal disease in companion animals due to the highly localized presence of cobalamin receptors in the ileum. An increasing body of evidence suggests that cobalamin deficiency is an important co-morbidity in many companion animal patients with gastrointestinal and pancreatic disease. Congenital disorders of cobalamin absorption and cellular metabolism are also increasingly recognized in companion animal breeds. The early recognition of these disorders and timely treatment with parenteral cobalamin can be life-saving. In this article, the normal mechanisms of cobalamin absorption, the use of cobalamin as a marker of intestinal disease and data on the prevalence of hypocobalaminemia in a variety of diseases are described. The prognostic impact of and rational therapy for hypocobalaminemia in domestic animals are discussed.

Folate and cobalamin status in relation to diet in healthy 2-y-old children

BACKGROUND

Limited data exist on sources of folate and cobalamin in the toddler diet.

OBJECTIVE

We examined the influence of diet on folate and cobalamin status in healthy toddlers in an unfortified population.

DESIGN

Dietary intake was assessed in 178 children, aged 24 mo, by using 7-d food records and related to serum folate and cobalamin status in 155 children.

RESULTS

Median (25th-75th percentile) daily intakes of folate and cobalamin were 87 μg (74-104 μg) and 3.1 μg (2.4-3.8 μg), respectively. Thirty-five percent of subjects had a folate intake below the Norwegian recommendations (80 μg folate/d), but only 5.8% of subjects had low serum folate concentrations (<10 nmol/L). All children reached the recommended cobalamin intake (0.8 μg cobalamin/d). Median (25th-75th percentile) serum concentrations were as follows: folate, 19 nmol/L (14-24 nmol/L); cobalamin, 410 pmol/L (334-521 pmol/L); holotranscobalamin, 94 pmol/L (67-121 pmol/L); holohaptocorrin, 315 pmol/L (241-409 pmol/L); methylmalonic acid, 0.16 μmol/L (0.13-0.20 μmol/L); and total homocysteine, 5.0 μmol/L (4.2-5.7 μmol/L). Folate intake correlated with serum folate concentrations (ρ = 0.25, P < 0.01), and cobalamin intake correlated with serum holotranscobalamin concentrations (ρ = 0.21, P < 0.05). In multivariate models, serum folate concentrations were significantly positively associated with the consumption of fruit and berries and grain products; however, this was not the case with dairy products, which was the food group that contributed most to folate intake. Cobalamin status was associated with dairy products (cobalamin and holotranscobalamin), cobalamin supplements (cobalamin and holohaptocorrin), and liver pâté (holotranscobalamin).

CONCLUSIONS

In this unfortified toddler population, folate status was associated with intakes of fruit and berries and grain products. Cobalamin status was associated with intakes of dairy, liver pâté, and supplements. In the assessment of vitamin sources, vitamin availability must be considered.

Subnormal vitamin B12 concentrations and anaemia in older people: a systematic review

BACKGROUND

Pernicious anaemia is undeniably associated with vitamin B12 deficiency, but the association between subnormal vitamin B12 concentrations and anaemia in older people is unclear. The aim of this systematic review was to evaluate the association between subnormal vitamin B12 concentrations and anaemia in older people.

METHODS

Clinical queries for aetiology and treatment in bibliographic databases (PubMed [01/1949-10/2009]; EMBASE [01/1980-10/2009]) were used. Reference lists were checked for additional relevant studies. Observational studies (> or =50 participants) and randomized placebo-controlled intervention trials (RCTs) were considered.

RESULTS

25 studies met the inclusion criteria. Twenty-one observational cross-sectional studies (total number of participants n = 16185) showed inconsistent results. In one longitudinal observational study, low vitamin B12 concentrations were not associated with an increased risk of anaemia (total n = 423). The 3 RCTs (total n = 210) were well-designed and showed no effect of vitamin B12 supplementation on haemoglobin concentrations during follow-up in subjects with subnormal vitamin B12 concentrations at the start of the study. Due to large clinical and methodological heterogeneity, statistical pooling of data was not performed.

CONCLUSIONS

Evidence of a positive association between a subnormal serum vitamin B12 concentration and anaemia in older people is limited and inconclusive. Further well-designed studies are needed to determine whether subnormal vitamin B12 is a risk factor for anaemia in older people.

Autoimmune Gastritis: Historical Antecedents, Outstanding Discoveries, and Unresolved Problems

The earliest recorded history of autoimmune gastritis can be traced to 1849 in London, when Thomas Addison described "a very remarkable form of anemia" later called pernicious (fatal) anemia (PA). This was followed by the recognition of a gastric mucosal defect suspected to have a nutritional basis, the discovery of the megaloblast that characterized the anemia, the insufficiency of a dietary extrinsic factor characterized as vitamin B12 (cobalamin), and a gastric-secreted intrinsic factor. Treatment with vitamin B12 proved curative. The link between PA and gastritis and atrophy was first confirmed histologically after immediate fixation of the stomach postmortem and later, in the 1940s, by peroral tube biopsy. The causes of gastritis remained enigmatic until the era of autoimmunity, when autoantibodies were detected first to gastric intrinsic factor and then to gastric parietal cells. Hints of a dichotomy in pathogenesis of gastritis were crystallized by the description in 1973 of Type A (Autoimmune) and Type B (later, Bacterial) gastritis. Clarification was enhanced by identification in Type A gastritis of the autoantigen of the parietal cell antibody, by the alpha and beta subunits of gastric H+/K+ ATPase, and by the highly informative experimental murine model of postneonatal thymectomy autoimmune gastritis, and in Type B of the causative role of gastric infection with Helicobacter pylori (H. pylori). A denouement will require a full understanding of (1) the origin and pathogenetic contribution of antibody to intrinsic factor; (2) the connection, if any, between H. pylori infection and Type A autoimmune gastritis; and (3) the genetic contributions to gastritis, whether due to autoimmunity or to H. pylori infection.

Syntheses and characterization of vitamin B12-Pt(II) conjugates and their adenosylation in an enzymatic assay

Aiming at the use of vitamin B12 as a drug delivery carrier for cytotoxic agents, we have reacted vitamin B12 with trans-[PtCl(NH3)2(H2O)]+, [PtCl3(NH3)](-) and [PtCl4](2-). These Pt(II) precursors coordinated directly to the Co(III)-bound cyanide, giving the conjugates [(Co)-CN-(trans-PtCl(NH3)2)]+ (5), [(Co)-CN-(trans-PtCl2(NH3))] (6), [(Co)-CN-(cis-PtCl2(NH3))] (7) and [(Co)-CN-(PtCl3)](-) (8) in good yields. Spectroscopic analyses for all compounds and X-ray structure elucidation for 5 and 7 confirmed their authenticity and the presence of the central "Co-CN-Pt" motif. Applicability of these heterodinuclear conjugates depends primarily on serum stability. Whereas 6 and 8 transmetallated rapidly to bovine serum albumin proteins, compounds 5 and 7 were reasonably stable. Around 20% of cyanocobalamin could be detected after 48 h, while the remaining 80% was still the respective vitamin B12 conjugates. Release of the platinum complexes from vitamin B12 is driven by intracellular reduction of Co(III) to Co(II) to Co(I) and subsequent adenosylation by the adenosyltransferase CobA. Despite bearing a rather large metal complex on the beta-axial position, the cobamides in 5 and 7 are recognized by the corrinoid adenosyltransferase enzyme that catalyzes the formation of the organometallic C-Co bond present in adenosylcobalamin after release of the Pt(II) complexes. Thus, vitamin B12 can potentially be used for delivering metal-containing compounds into cells.

Roles of vitamins B5, B8, B9, B12 and molybdenum cofactor at cellular and organismal levels

Many efforts have been made in recent decades to understand how coenzymes, including vitamins, are synthesised in organisms. In the present review, we describe the most recent findings about the biological roles of five coenzymes: folate (vitamin B9), pantothenate (vitamin B5), cobalamin (vitamin B12), biotin (vitamin B8) and molybdenum cofactor (Moco). In the first part, we will emphasise their biological functions, including the specific roles found in some organisms. In the second part we will present some nutritional aspects and potential strategies to enhance the cofactor contents in organisms of interest.

A hundred years of cascading - started by Paul Morawitz (1879-1936), a pioneer of haemostasis and of transfusion

Morawitz is mainly remembered for clarifying the role of prothrombin in clotting, but his mature years saw him guide advances in transfusion therapy. He was among the first to describe haemolytic transfusion reactions and to advocate using blood anticoagulated by citrate. He was a talented organiser - founding the Leipzig Donor Centre during increasingly difficult economic and political times. An excellent general physician, his interest in clotting led to clinical work in thrombosis and angina, and the use of quinidine for cardiac dysfunction. Ironically he died of acute myocardial infarction two years after his first attack of angina and coronary thrombosis.

Gastritis in Neonatal BALB/cCrSlc Mice Induced by Immunization Without Adjuvant can be Transferred to Syngeneic nu/nu Recipients

The popularly exploited murine neonatal thymectomy experimental autoimmune gastritis (nTx:EAG) model requires the animal to be in a state of lymphopenia. Here we report on a novel murine immunization (without adjuvant) model that can establish a lasting gastritis. We demonstrate that the immunization model (imm:EAG) results in a bona fide autoimmune disease and define the resulting pathology and serology observed and compare it with that reported for human autoimmune gastritis. Immune cells present in the stomachs of imm:EAG gastritic mice include CD8 T cells, CD11b and Gr1 (granulocytes/monocytes) and B cells. We detected circulating antibodies of immunoglobulin G1 (IgG1) subclass, with some IgG(2a) and IgG(2b) reactive to stomach membranes and the parietal cell proton pump. The class and subclass of autoreactive antibodies resulting from imm:EAG suggest a T helper 1 (Th1)/Th2 immune response. We establish that both self-reactive T and B cells from BALB/cCrSlc imm:EAG gastritic mice have the potential to induce a gastritis in BALB/c syngeneic nu/nu recipients. We conclude that this model is likely to be superior to the currently popularly exploited nTx:EAG and provide insight into and an understanding of the mechanisms of and remedies for autoimmunity in an intact immune system.

Variable hematologic presentation of autoimmune gastritis: age-related progression from iron deficiency to cobalamin depletion

Iron deficiency is a known complication of achlorhydria and may precede the development of pernicious anemia. Among 160 patients with autoimmune gastritis identified by hypergastrinemia and strongly positive antiparietal antibodies, we explored the overlap between 83 subjects presenting with iron deficiency anemia (IDA), 48 with normocytic indices, and 29 with macrocytic anemia. Compared with macrocytic patients, patients with IDA were 21 years younger (41 +/- 15 years versus 62 +/- 15 years) and mostly women. All groups had a high prevalence of thyroid disease (20%) and diabetes (8%) suggestive of the autoimmune polyendocrine syndrome. Stratification by age cohorts from younger than 20 years to older than 60 years showed a regular and progressive increase in mean corpuscular volume (MCV) from 68 +/- 9 to 95 +/- 16 fl, serum ferritin levels from 4 +/- 2 to 37 +/- 41 microg/L, gastrin level from 166 +/- 118 to 382 +/- 299 pM/L (349 +/- 247 to 800 +/- 627 pg/mL), and a decrease in cobalamin level from 392 +/- 179 to 108 +/- 65 pg/mL. The prevalence of Helicobacter pylori infection was 87.5% at age younger than 20 years, 47% at age 20 to 40 years, 37.5% at 41 to 60 years, and 12.5% at age older than 60 years. These findings challenge the common notion that pernicious anemia is a disease of the elderly and imply a disease starting many years before the establishment of clinical cobalamin deficiency, by an autoimmune process likely triggered by H pylori.

Human intrinsic factor expressed in the plant Arabidopsis thaliana

Intrinsic factor (IF) is the gastric protein that promotes the intestinal uptake of vitamin B12. Gastric IF from animal sources is used in diagnostic tests and in vitamin pills. However, administration of animal IF to humans becomes disadvantageous because of possible pathogenic transmission and contamination by other B12 binders. We tested the use of recombinant plants for large-scale production of pathogen-free human recombinant IF. Human IF was successfully expressed in the recombinant plant Arabidopsis thaliana. Extract from fresh plants possessed high B12-binding capacity corresponding to 70 mg IF per 1 kg wet weight. The dried plants still retained 60% of the IF activity. The purified IF preparation consisted of a 50-kDa glycosylated protein with the N-terminal sequence of mature IF. Approximately one-third of the protein was cleaved at the internal site em leader PSNP downward arrow GPGP. The key properties of the preparation obtained were identical to those of native IF: the binding curves of vitamin B12 to recombinant IF and gastric IF were the same, as were those for a B12 analogue cobinamide, which binds to IF with low affinity. The absorbance spectra of the vitamin bound to recombinant IF and gastric IF were alike, as was the interaction of recombinant and native IF with the specific receptor cubilin. The data presented show that recombinant plants have a great potential as a large-scale source of human IF for analytical and therapeutic purposes.

Animal models of human disease: experimental autoimmune gastritis--a model for autoimmune gastritis and pernicious anemia

Human autoimmune gastritis is an organ-specific autoimmune disease of the stomach. It is characterized by the development of disease-specific autoantibodies and a pathology that specifically targets specialized cells within the gastric environment. The autoantigens associated with this disease have been defined as the gastric H+/K+ ATPase and intrinsic factor. The development of experimental disease models has been pivotal in our contemporary understanding of autoimmunity. Here we review mouse models of autoimmune gastritis and their relevance to human autoimmune gastritis associated with pernicious anemia. We appraise some historical as well as recent studies of experimental autoimmune gastritis (EAG), highlighting key findings that have formed the basis of our current understanding of the etiology and mechanism(s) associated with autoimmune gastritis. A precise understanding of the pathogenesis of autoimmune gastritis will permit the design of innovative and rational therapeutic strategies to prevent, arrest, ameliorate or reverse the disease.