Cobalamin, folic acid, and homocysteine

Relationship between vitamin B12 and sensory and motor peripheral nerve function in older adults

OBJECTIVES

To examine whether deficient B12 status or low serum B12 levels are associated with worse sensory and motor peripheral nerve function in older adults.

DESIGN

Cross-sectional.

SETTING

Health, Aging and Body Composition Study.

PARTICIPANTS

Two thousand two hundred and eighty-seven adults aged 72 to 83 (mean 76.5 ± 2.9; 51.4% female; 38.3% black).

MEASUREMENTS

Low serum B12 was defined as serum B12 less than 260 pmol/L, and deficient B12 status was defined as B12 less than 260 pmol/L, methylmalonic acid (MMA) greater than 271 nmol/L, and MMA greater than 2-methylcitrate. Peripheral nerve function was assessed according to peroneal nerve conduction amplitude and velocity (NCV) (motor), 1.4 g/10 g monofilament detection, average vibration threshold detection, and peripheral neuropathy symptoms (numbness, aching or burning pain, or both) (sensory).

RESULTS

B12-deficient status was found in 7.0% of participants, and an additional 10.1% had low serum B12 levels. B12 deficient status was associated with greater insensitivity to light (1.4 g) touch (odds ratio = 1.50, 95% confidence interval = 1.06-2.13) and worse NCV (42.3 vs 43.5 m/s) (β = -1.16, P = .01) after multivariable adjustment for demographics, lifestyle factors, and health conditions. Associations were consistent for the alternative definition using low serum B12 only. No significant associations were found for deficient B12 status or the alternative low serum B12 definition and vibration detection, nerve conduction amplitude, or peripheral neuropathy symptoms.

CONCLUSION

Poor B12 (deficient B12 status and low serum B12) is associated with worse sensory and motor peripheral nerve function. Nerve function impairments may lead to physical function declines and disability in older adults, suggesting that prevention and treatment of low B12 levels may be important to evaluate.

The reaction of HOCl and cyanocobalamin: corrin destruction and the liberation of cyanogen chloride

Overproduction of hypochlorous acid (HOCl) has been associated with the development of a variety of disorders such as inflammation, heart disease, pulmonary fibrosis, and cancer through its ability to modify various biomolecules. HOCl is a potent oxidant generated by the myeloperoxidase-hydrogen peroxide-chloride system. Recently, we have provided evidence to support the important link between higher levels of HOCl and heme destruction and free iron release from hemoglobin and RBCs. Our current findings extend this work and show the ability of HOCl to mediate the destruction of metal-ion derivatives of tetrapyrrole macrocyclic rings, such as cyanocobalamin (Cobl), a common pharmacological form of vitamin B12. Cyanocobalamin is a water-soluble vitamin that plays an essential role as an enzyme cofactor and antioxidant, modulating nucleic acid metabolism and gene regulation. It is widely used as a therapeutic agent and supplement, because of its efficacy and stability. In this report, we demonstrate that although Cobl can be an excellent antioxidant, exposure to high levels of HOCl can overcome the beneficial effects of Cobl and generate proinflammatory reaction products. Our rapid kinetic, HPLC, and mass spectrometric analyses showed that HOCl can mediate corrin ring destruction and liberate cyanogen chloride (CNCl) through a mechanism that initially involves α-axial ligand replacement in Cobl to form a chlorinated derivative, hydrolysis, and cleavage of the phosphonucleotide moiety. Additionally, it can liberate free Co, which can perpetuate metal-ion-induced oxidant stress. Taken together, these results are the first report of the generation of toxic molecular products through the interaction of Cobl with HOCl.

Vitamin B12 and folate statuses are associated with diet in pregnant women, but not with anthropometric measurements in term newborns

OBJECTIVE

To investigate the frequencies of vitamin B12 and folate deficiencies in pregnant women in low socioeconomic group, the relation between the animal-source foods consumption and maternal vitamin B12-folate statuses, and their impacts on anthropometric measurements of the infants.

METHODS

A total of 208 pregnant women in the last trimester were included in the study. A questionnaire about socio-demographic status, consumption of meat, egg, milk-dairy products, multivitamin supplementation was used. Vitamin B(12) and folate concentrations were studied by chemiluminescence method. The babies of Vitamin B(12) deficient mothers were evaluated after birth.

RESULTS

The rate of vitamin B(12) deficiency was 47.6% and folate deficiency was 17.3% of pregnant women. Animal food consumption was inadequate about half of pregnant women and vitamin B(12) levels in these women were significantly low. There were no statistically significant relationships between the birth weight, birth length and head circumference measurements, and maternal vitamin B(12) and folate concentrations.

CONCLUSION

The rate of vitamin B12 deficiency in pregnant women in low socioeconomic population is high. Although there were no significant effects of the vitamin B12 and folate deficiencies on birth size, additional studies are required to elucidate the subsequent effects.

Vitamin B12 and homocysteine levels and 6-year change in peripheral nerve function and neurological signs

BACKGROUND

Low vitamin B12 and high homocysteine (Hcy) levels are common in older adults and may be associated with worse neurological function. The aim of this study is to determine whether changes in B12 or Hcy levels are associated with longitudinal changes in peripheral nerve function and clinical neurological signs and symptoms.

METHODS

Participants aged 60 years and older at baseline (n = 678; 72.2 ± 6.2 years; 43.5% male) were from the InCHIANTI Study. Low B12 (<260 pmol/L) and high Hcy (≥13 μmol/L) were measured at baseline and 3-year follow-up. Neurological function was assessed by peroneal nerve conduction amplitude (compound motor action potential) and velocity, neurological examination, and peripheral neuropathy symptoms at baseline, 3-year, and 6-year follow-up.

RESULTS

At baseline, 43.8% had low B12 levels and 58.6% had high Hcy levels. Over 6 years, 12.4% declined to poor compound motor action potential (<1 mV) and 42.1% declined to poor nerve conduction velocity (<40 m/s). In mixed models analyses, sustained high Hcy was associated with worse compound motor action potential compared with sustained normal Hcy (p = .04), adjusting for demographics, diabetes, and folate level. Participants whose Hcy level became high at follow-up were more likely to become unable to detect monofilament at 6-year follow-up compared with those with sustained normal Hcy (odds ratio: 5.4; 95% CI: 1.5-19.0), adjusting for demographics, diabetes, body mass index, and peripheral arterial disease. There was no association with vitamin B12 level or with symptoms.

CONCLUSIONS

High Hcy may be associated with worse sensory and motor peripheral nerve function. Because poor nerve function has been associated with lower strength and physical performance, these results have important implications for disability in older adults.

Anaemia in pregnancy

Anaemia in pregnancy, defined as a haemoglobin concentration (Hb) < 110 g/L, affects more than 56 million women globally, two thirds of them being from Asia. Multiple factors lead to anaemia in pregnancy, nutritional iron deficiency anaemia (IDA) being the commonest. Underlying inflammatory conditions, physiological haemodilution and several factors affecting Hb and iron status in pregnancy lead to difficulties in establishing a definitive diagnosis. IDA is associated with increased maternal and perinatal morbidity and mortality, and long-term adverse effects in the new born. Strategies to prevent anaemia in pregnancy and its adverse effects include treatment of underlying conditions, iron and folate supplementation given weekly for all menstruating women including adolescents and daily for women during pregnancy and the post partum period, and delayed clamping of the umbilical cord at delivery. Oral iron is preferable to intravenous therapy for treatment of IDA. B12 and folate deficiencies in pregnancy are rare and may be due to inadequate dietary intake with the latter being more common. These vitamins play an important role in embryo genesis and hence any relative deficiencies may result in congenital abnormalities. Finding the underlying cause are crucial to the management of these deficiencies. Haemolytic anaemias rare also rare in pregnancy, but may have life-threatening complications if the diagnosis is not made in good time and acted upon appropriately.

Iron, folate and vitamin B12 levels in first trimester pregnancies in the Southwest region of Turkey

OBJECTIVE

Iron, folate and vitamin B12 play important roles in the healthy development of the fetus in pregnancy. Preconceptional levels of these micronutrients is influenced by dietary habits. The purpose of this study was to investigate the status of iron, vitamin B12 and folate in first trimester pregnancies in the southwest region of Turkey where the Mediterranean Cuisine, rich in fresh fruit and vegetables is commonly consumed.

MATERIAL AND METHODS

Two hundred and one low-middle income pregnant women were recruited during their first prenatal visit. Hemoglobin, ferritin, folate and vitamin B12 levels were evaluated and a structured questionnaire was given to gather information including age, gravida, parity, frequency of pregnancy, history of abortion, and intrauterine device usage. Based on WHO and international guidelines, anemia was defined as hemoglobin <11 g/dl, and iron deficiency as ferritin <15 μg/L. Serum folate and vitamin B12 deficiencies were defined as levels below 3 ng/ml and 200 pg/ml respectively.

RESULTS

The mean age and gestational week were 26.4±5.3 years and 9±3 weeks respectively. Mean plasma concentrations were 12.8±9.7 g/dl for hemoglobin, 22.7±17.2 μg/L for ferritin, 12.2±5.6 ng/ml for folate and 266.6±100.2 pg/ml for vitamin B12. Anemia was detected in 4.5% of pregnant women, iron deficiency in 40.3%, vitamin B12 deficiency in 29.8% and folate deficiency in 0.5% of patients. In 10.9% of patients, both vitamin B12 and iron iron deficiency was detected. There was no significant difference for age, body mass index, gravida, parity, frequency of pregnancy, history of abortion, and intrauterine device usage between women with low and normal levels of vitamin B12 and Ferritin (p>0.05).

CONCLUSION

Iron and vitamin B12 deficiencies were relatively common in the pregnant population consuming vegetable based diets. Iron and vitamin B12 supplementation in addition to folate must be considered for the wellbeing of the fetus in pregnant women living in areas where dietary patterns are mainly vegetable based.

Neurotoxicity of cobalt

Cobalt exerts well-known and documented toxic effects on the thyroid, heart and the haematopoietic system, in addition to the occupational lung disease, allergic manifestations and a probably carcinogenic action. Cobalt neurotoxicity is reported in isolated cases, and it has never been systematically treated. Bilateral optic atrophy and retinopathy, bilateral nerve deafness and sensory-motor polyneuropathy have been described long ago as a result of chronic occupational exposure to cobal powder or during long-term treatment of anaemia with cobalt chloride. Recently, some patients with high levels of cobalt released from metal prosthesis have been referred as presenting with tinnitus, deafness, vertigo, visual changes, optic atrophy, tremor and peripheral neuropathy. The aim of this work is to group these cases and to identify a possible mechanism of cobalt neurotoxicity, focusing on hypothetic individual susceptibility such as altered metal-binding proteins, altered transport processes in target cells or polymorphic variation of genetic background.

Determinants of hyperhomocysteinemia after gastric bypass surgery in obese subjects

BACKGROUND

Effectiveness of gastric bypass (GBP) on reduction of vascular risk factors is well established, but GBP induces nutritional deficits that could reduce the cardiovascular benefit of weight loss. Particularly, hyperhomocysteinemia, now clearly identified as a vascular risk factor, has been described after GBP. The aim of this study was to clarify the factors associated with increased homocysteine concentration after GBP.

METHODS

Homocysteine concentration and multiple nutritional parameters were measured in 213 consecutive subjects. One hundred and eight subjects were studied before surgery (control (CT)), 115 one to 6 years after GBP, and 41 both before and 6 months after GBP.

RESULTS

Homocysteine concentration did not differ before and after GBP (9.1 ± 3.2 vs 8.6 ± 3.4 μmol/l), but 94% of subjects had been supplemented with a multivitamin preparation after surgery. The nutritional parameters best correlated with homocysteine concentration both before and after GBP were folate and creatinine concentrations (p < 0.0001). In contrast, vitamin B12 and metabolic parameters (including glucose, insulin, lipids and C-reactive protein) were not associated with homocysteine concentration. After GBP, homocysteine concentration was significantly lower in subjects taking a multivitamin supplementation containing a high dose of folate than those who did not (7.7 ± 2.8 vs 10.1 ± 3.9 μmol/l, p < 0.0001).

CONCLUSIONS

The main determinants of homocysteine concentration identified in this study are folate and serum creatinine. Multivitamin supplementation with a high dose of folate prevents hyperhomocysteinemia after GBP.

Oral manifestations of hematologic and nutritional diseases

Oral manifestations of hematologic and nutritional deficiencies can affect the mucous membranes, teeth, periodontal tissues, salivary glands, and perioral skin. This article reviews common oral manifestations of hematologic conditions starting with disorders of the white blood cells including cyclic hematopoiesis (cyclic neutropenia), leukemias, lymphomas, plasma cell dyscrasias, and mast cell disorders; this is followed by a discussion of the impact of red blood cell disorders including anemias and less common red blood cell dyscrasias (sickle cell disease, hemochromatosis, and congenital erythropoietic porphyria) as well as thrombocytopenia. Several nutritional deficiencies exhibit oral manifestations. The authors specifically discuss the impact of water-soluble vitamins (B2, B3, B6, B9, B12, and C), fat-soluble vitamins (A, D, and K) and the eating disorders anorexia nervosa and bulimia nervosa on the oral mucosa.

A simplified method for the determination of total homocysteine in plasma by electrospray tandem mass spectrometry

Hyperhomocysteinemia is a risk factor for different diseases. Several methods have been developed to analyze homocysteine and the immunometric ones, although expensive, they are in widespread use. A rapid LC-MS/MS method for homocysteine assay has been developed for the application of large clinical chemistry routines. Selected reaction monitoring was performed through the transitions m/z 136.0→90.1 for homocysteine and m/z 140.0→94.0 for the internal standard. ESI was used to generate [H+] adduct ions. Chromatographic isocratic separation was achieved using a strong cation exchange column. The mobile phase was methanol/water (20:80  v/v, containing 0.1% formic acid and 1.5  mmol/L ammonium formate in the water phase) at a flow rate of 0.250  mL/min (35°C). Samples treatment consisted in the reduction with DTT and deproteinization with methanol. Recovery, linearity, LOD, LOQ and total imprecision were evaluated to validate the method. Homocysteine values on 100 serum samples were compared with those obtained by HPLC and immunometric methods. The method is robust, selective and precise in the whole range of values studied. Moreover, low reagent cost and easiness of sample treatment make this method useful, not only for research, but also for routine work.

Higher maternal plasma folate but not vitamin B-12 concentrations during pregnancy are associated with better cognitive function scores in 9- to 10- year-old children in South India

Folate and vitamin B-12 are essential for normal brain development. Few studies have examined the relationship of maternal folate and vitamin B-12 status during pregnancy and offspring cognitive function. To test the hypothesis that lower maternal plasma folate and vitamin B-12 concentrations and higher plasma homocysteine concentrations during pregnancy are associated with poorer neurodevelopment, 536 children (aged 9-10 y) from the Mysore Parthenon birth cohort underwent cognitive function assessment during 2007-2008 using 3 core tests from the Kaufman Assessment Battery, and additional tests measuring learning, long-term storage/retrieval, attention and concentration, and visuo-spatial and verbal abilities. Maternal folate, vitamin B-12, and homocysteine concentrations were measured at 30 +/- 2 wk gestation. During pregnancy, 4% of mothers had low folate concentrations (<7 nmol/L), 42.5% had low vitamin B-12 concentrations (<150 pmol/L), and 3% had hyperhomocysteinemia (>10 micromol/L). The children's cognitive test scores increased by 0.1-0.2 SD per SD increase across the entire range of maternal folate concentrations (P < 0.001 for all), with no apparent associations at the deficiency level. The associations with learning, long-term storage/retrieval, visuo-spatial ability, attention, and concentration were independent of the parents' education, socioeconomic status, religion, and the child's sex, age, current size, and folate and vitamin B-12 concentrations. There were no consistent associations of maternal vitamin B-12 and homocysteine concentrations with childhood cognitive performance. In this Indian population, higher maternal folate, but not vitamin B-12, concentrations during pregnancy predicted better childhood cognitive ability. It also suggests that, in terms of neurodevelopment, the concentration used to define folate deficiency may be set too low.

Extending the knowledge in histochemistry and cell biology

Central to modern Histochemistry and Cell Biology stands the need for visualization of cellular and molecular processes. In the past several years, a variety of techniques has been achieved bridging traditional light microscopy, fluorescence microscopy and electron microscopy with powerful software-based post-processing and computer modeling. Researchers now have various tools available to investigate problems of interest from bird's- up to worm's-eye of view, focusing on tissues, cells, proteins or finally single molecules. Applications of new approaches in combination with well-established traditional techniques of mRNA, DNA or protein analysis have led to enlightening and prudent studies which have paved the way toward a better understanding of not only physiological but also pathological processes in the field of cell biology. This review is intended to summarize articles standing for the progress made in "histo-biochemical" techniques and their manifold applications.