Effect of Vitamin B12 Treatment on Haptocorrin

Effect of 8-week oral supplementation with 3-µg cyano-B12 or hydroxo-B12 in a vitamin B12-deficient population

“…Furthermore, Rajan et al [24] found that a daily dose of 25 and 100-µg B12 could not normalize MMA and Hcy within 6 weeks in a population of B12-deficient elderly. On the other hand, Rajan et al [24] and Morkbak et al [25] both demonstrated that high pharmacological doses of B12 (above 1000 µg/day) normalized the levels of Hcy or MMA within 4-6 weeks in B12-deficient elderly and vegans, respectively. Altogether, our data and the previous intervention studies [6,7,24,25] indicate that the daily dose of B12 supplementation needs to contain quantities far above the RDA of 2.4-µg/day, to restore the optimal biomarkers of B12 status in individuals with a low B12 status due to inadequate intake.…”

A New Principle for Measurement of Cobalamin and Corrinoids, Used for Studies of Cobalamin Analogs on Serum Haptocorrin

“…On addition to the released corrinoids of apoTC (for measurement of Cbls) or apoHC (for measurement of the total amount of corrinoids), holoTC or holoHC can be measured by using established ELISAs (15,17 ). The assays have 2 advantages.…”

“…The amounts of holoTC present in serum and holoHC present in plasma were analyzed as previously described (15,17 ). Total Cbl was analyzed by use of a Centaur Analyzer (Siemens) employing the analytical kit supplied by the manufacturer.…”

“…The final concentrations of the calibrators ranged from 8 -484 pmol/L. Measurement of HC saturated with corrinoids (holoHC, corresponding to the amount of total corrinoids in the calibrators/samples) was performed as previously described (17 ).…”

Haptocorrin (Transcobalamin I) and Cobalamin Deficiencies

“…The clinical ramifications are important. To the Editor: Dr. Carmel was the first to report that total haptocorrin (HC) and cobalamins are related and that this relationship may be associated with the occurrence of heterozygosity for HC deficiency (1 ). The rarity of HC deficiency, however, suggests that this explanation is probably incomplete.…”