Cobalamin: a critical vitamin in the elderly

Wolters, Maike; Schmeißer, Alexander; Hahn, Andreas

doi:10.1016/j.ypmed.2004.04.047

Cited by 152 publications

(136 citation statements)

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“…Recently, accumulating evidences have shown that vitamin B12 deficiency is a relatively common disease, whose prevalence increases with aging [1,2] . Vitamin B12 deficiency is a worldwide problem, and some researchers regard vitamin B12 as a critical vitamin in old population [3] . Vitamin B12 deficiency occurs frequently among elderly patients (about 5%-40% of the aged population), depending on the diagnostic criteria used [4][5][6] , but it is often unrecognized or not investigated due to the subtle clinical manifestations.…”

Section: Introductionmentioning

confidence: 99%

An investigation of vitamin B12 deficiency in elderly inpatients in neurology department

et al. 2009

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Objective To investigate the status of vitamin B12 deficiency in elderly inpatients in the department of neurology.Methods A total number of 827 patients in the department of neurology of Shanghai Punan hospital, from March 2007 to July 2008, were employed in the present study. They were 60 years or older, and the average age was 77.1±7.5 years old. All the patients were diagnosed with no severe hepatic or renal dysfunction, without any usage of vitamin B12 during the previous 3 months before the detection. The levels of serum vitamin B12, folate and homocysteine (Hcy) were evaluated. The patients with vitamin B12 deficiency were screened. The resulting symptoms, positive signs of neurological examination, and the neuroelectricphysiological results were compared between patients with or without vitamin B12 deficiency. Results Vitamin B12 deficiency was found in 163 patients (19.71% of the total patients), and was more prevalent in female than in male patients, also with increased incidences with aging. Patients with low levels of serum vitamin B12 exhibited higher rate of gastrointestinal diseases, while only 9.82% of the vitamin B12 deficient patients had megaloblastic anemia. Symptoms of vitamin B12 deficiency included unsteadily walking in the darkness and hypopallesthesia, and some chronic diseases such as cerebral ischemia, hypertension, Parkinson's disease (Parkinsonism), diabetes mellitus and coronary heart disease. Most of the vitamin B12 deficient patients had neuroelectricphysiological abnormalities. Conclusion Vitamin B12 deficiency is remarkably common in elderly patients in neurology department, with various and atypical clinical manifestations, and the neurological symptoms are more common than megaloblastic anemia symptoms.

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Section: Introductionmentioning

confidence: 99%

An investigation of vitamin B12 deficiency in elderly inpatients in neurology department

et al. 2009

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“…The most common cause of vitamin B 12 deficiency, especially among the elderly population, is failure at one of the steps to internalize Cbl rather than lack of Cbl in the diet (9). The accompanying disorders include hematologic abnormalities and defects in the nervous system and metabolism (9).…”

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Structural basis for mammalian vitamin B ₁₂ transport by transcobalamin

Wuerges

Garau²,

Geremia³

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

166

216

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Cobalamin (Cbl, vitamin B12) serves for two essential cofactors in mammals. The pathway for its intestinal absorption, plasma transport, and cellular uptake uses cell surface receptors and three Cbl-transporting proteins, haptocorrin, intrinsic factor, and transcobalamin (TC). We present the structure determination of a member of the mammalian Cbl-transporter family. The crystal structures of recombinant human and bovine holo-TCs reveal a two-domain architecture, with an N-terminal ␣6-␣6 barrel and a smaller C-terminal domain. One Cbl molecule in base-on conformation is buried inside the domain interface. Structural data combined with previous binding assays indicate a domain motion in the first step of Cbl binding. In a second step, the weakly coordinated ligand H 2O at the upper axial side of added H2O-Cbl is displaced by a histidine residue of the ␣6-␣6 barrel. Analysis of amino acid conservation on TC's surface in orthologous proteins suggests the location of the TC-receptor-recognition site in an extended region on the ␣6-␣6 barrel. The TC structure allows for the mapping of sites of amino acid variation due to polymorphisms of the human TC gene. Structural information is used to predict the overall fold of haptocorrin and intrinsic factor and permits a rational approach to the design of new Cbl-based bioconjugates for diagnostic or therapeutic drug delivery.cobalamin ͉ crystal structure ͉ P259R polymorphism ͉ transport protein

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“…La dissociation du complexe vitamine B12-protéines alimentaires est alors réduite en raison de l'achlorhydrie induite par les médicaments : la vitamine B12 ne peut donc pas se lier au FI. De plus, l'achlorhydrie favorise la pullulation bactérienne : la vitamine B12 est alors catabolisée par les bactéries [86] ; -l'intoxication alcoolique chronique ; -les interventions de chirurgie ou de plastie gastrique (en particulier le bypass réalisé pour traiter une obésité) ; -l'insuffisance pancréatique exocrine partielle [23,61] ; -le syndrome de Sjögren [3] ; -la sclérodermie ; -. .…”

Section: Syndrome De Non-dissociation De La Vitamine B12 Des Protéineunclassified

Carence en vitamine B12 (1^repartie) : mise au point

Loup-Leuciuc

Loup

Lombardi

et al. 2011

Med Buccale Chir Buccale

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(Reçu le 12 mai 2011, accepté le 24 juin 2011) Mots clés : vitamine B12 / métabolisme / carence / manifestationsRésumé -Classiquement, la carence en vitamine B12 s'accompagne d'une anémie mégaloblastique, de manifestations neuropsychiatriques et d'une glossite de Hunter. En réalité, les manifestations sont protéiformes et chacune d'elles peut rester longtemps isolée. Les manifestations stomatologiques, souvent discrètes, peuvent précéder de plusieurs années les autres manifestations. Elles constituent parfois un signe d'appel pour le dépistage précoce de cette carence. Depuis une bonne dizaine d'années, la conception de la physiopathologie de la carence en vitamine B12 a beaucoup évolué : on a identifié le syndrome de non-dissociation de la vitamine B12 des protéines porteuses qui constitue maintenant la principale cause de carence en vitamine B12 et il a été démontré qu'on peut effectuer un traitement de la carence per os. Key words: vitamin B12 / metabolism / deficiency / manifestationsAbstract -Vitamin B12 deficency. Part 1: update and littérature review. Vitamin B12 deficiency is classically accompanied by a megaloblastic anemia, neuropsychiatric disorders and an Hunter glossitis. Clinical manifestations are indeed polymorphic and each may remain the only one for a long period of time. Stomatological manifestations, often mild, may precede the others of many years. They sometimes are the first sign to early diagnose this deficiency. Since the last ten years, the physiopathology of vitamin B12 deficiency has considerably changed. In fact, nowadays, the main cause is the syndrome of food cobalamin malabsorption. It has also been demonstrated that the deficiency may now treated by an oral cobalamin therapy.La vitamine B12 est une vitamine hydrosoluble qui a une structure chimique proche de celle de l'hème avec un atome central constitué par du cobalt, d'où le nom de cobalamine (Fig. 1).Elle existe sous plusieurs formes regroupées dans la famille des cobalamines : cyanocobalamine, hydroxocobalamine, mé-thylcobalamine et adénosylcobalamine. La cyanocobalamine et l'hydroxocobalamine sont les seules formes stables. On peut considérer que les recherches sur la vitamine B12 ont commencé au XIX e siècle avec la description d'une anémie mortelle, l'anémie pernicieuse, par Thomas Addison et Michael Anton Biermer. Vers 1920, George Whipple, George Minot et William Murphy, tous les trois Prix Nobel de médecine en 1934, ont démontré que des extraits de foie sous forme de compléments alimentaires étaient susceptibles de corriger certaines anémies. On en a conclu que les extraits de foie contenaient le facteur extrinsèque, en réalité de la vitamine

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Cobalamin: a critical vitamin in the elderly

Cited by 152 publications

References 115 publications

An investigation of vitamin B12 deficiency in elderly inpatients in neurology department

An investigation of vitamin B12 deficiency in elderly inpatients in neurology department

Structural basis for mammalian vitamin B ₁₂ transport by transcobalamin

Carence en vitamine B12 (1^repartie) : mise au point

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Cobalamin: a critical vitamin in the elderly

Cited by 152 publications

References 115 publications

An investigation of vitamin B12 deficiency in elderly inpatients in neurology department

An investigation of vitamin B12 deficiency in elderly inpatients in neurology department

Structural basis for mammalian vitamin B 12 transport by transcobalamin

Carence en vitamine B12 (1repartie) : mise au point

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Structural basis for mammalian vitamin B ₁₂ transport by transcobalamin

Carence en vitamine B12 (1^repartie) : mise au point