Hibiscus sabdariffa increases hydroxocobalamin oral bioavailability and clinical efficacy in vitamin B12 deficiency with neurological symptoms

The aim of the study was to evaluate the bioavailability and clinical benefits of oral new formulation (HB₁₂) of hydroxocobalamin (Hdrx) with Hibiscus sabdariffa (HS). First, in an observational study, a cohort of 30 vitamin B₁₂‐deficient patients (vit B₁₂ < 200 pg/mL) with neurological symptoms received oral fixed dose of Hdrx containing 15 mg Hdrx daily for 10 days followed by 15 mg monthly. Clinical benefits were evaluated on haematological and biochemical parameters, and neurological improvement at days 10 and 90 compared to day 0. To understand the mechanism, intestinal mucosa from mice were mounted in vitro in Ussing chambers to measure Hdrx Fluxes. In the clinical study, serum vitamin B₁₂ level increased from 55.1 ± 36.9 to 1330 ± 335.5 pg/mL at day 10 and 431.0 ± 24.27 pg/mL at day 90, without overt adverse effects. In mice ileum, (i) intestinal bioavailability of Hdrx increased in dose‐dependent manner with HB₁₂. The apparent permeability of Hdrx was P_app = 34.9 ± 4.6 × 10^?6 cm/s in the presence of 3 mg/mL (HB₁₂B) compared to the control P_app = 6.2 ± 0.7 × 10^?6 cm/s. (ii) Total transepithelial electrical conductance (G_t) increased in dose‐dependent manner with HB₁₂, G_t = 161.5 ± 10.8 mS/cm² with HB₁₂B (Hdrx 1 mg + HS 3 mg) compared to the control Hdrx, G_t = 28.7 ± 4.0 mS/cm². In conclusion, the clinical study suggests that injections are not required when Hdrx is given orally. Intestinal bioavailability of Hdrx increased in vitro when it was used concomitantly with HS.     

Genetic polymorphisms predisposing to hyperhomocysteinemia in cardiac transplant patients

Genetic determinants for high homocysteine (Hcy) levels are now well known. We studied several single nucleotide polymorphisms (SNP) in Hcy-regulating genes [methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C; methionine synthase (MS) A2756G; methionine synthase reductase (MTRR) A66G] in relation to total plasma Hcy levels, transplant coronary artery disease and thromboembolic episodes in 84 heart transplant patients, and we compared the incidence of these polymorphisms with those in a healthy adult controls. At least one copy of the G allele of the MTRR A66G SNP was found in a significantly greater proportion of cardiac transplant (CTX) recipients compared with controls (94.0% vs. 79.9% respectively). None of the SNP analyzed were correlated with total Hcy plasma levels or the presence of transplant coronary artery disease. However, MS A2756G was significantly associated with cobalamin levels (AA genotype: 290 +/- 122 pmol/l; AG: 381 +/- 151 pmol/l and GG: 415 +/- 100 pmol/l), as was MTRR A66G (AA: 478 +/- 219 pmol/l, AG: 306 +/- 124 pmol/l and GG: 306 +/- 123 pmol/l). MTRR A66G was also correlated with serum folate. No association was found with thromboembolic events. In conclusion, there was a significant difference in the frequency of the G allele genotype of the MTRR A66G in CTX patients versus controls. Differences in cobalamin and folate levels with the MTRR A66G and MS A2756G polymorphisms were noted. Thus, SNP in Hcy-regulating genes may be important determinants of vitamin metabolism in CTX, raising the question of increased vitamin requirements to minimize increased plasma Hcy in this high-risk group.     

Serum cobalamin, folate, methylmalonic acid and total homocysteine as vitamin B12 and folate tissue deficiency markers amongst elderly Swedes--a population-based study

OBJECTIVES: The possibilities of detecting tissue cobalamin and folate deficiency are under debate. In this report the levels of serum cobalamin, folate, methylmalonic acid (MMA) and total homocysteine (tHcy) and their interrelations in a representative random population sample are presented. DESIGN: Cohort study. SETTING: A general mid-Swedish population. SUBJECTS: A 20% random sample of persons 70 years or older in a defined geographical area were invited to a survey. A total of 235 (85%) persons responded, out of whom 224 had no interfering diseases. MAIN OUTCOME MEASURES: Serum cobalamin, folate, MMA and tHcy. RESULTS: The serum levels of cobalamin, folate, MMA and tHcy were all correlated to cobalamin and folic acid treatment. They were also correlated to the intake of multivitamin preparations. In addition, serum cobalamin was higher in untreated women than in men but not correlated to age. Serum folate was correlated neither to sex nor age. Serum tHcy and MMA were both directly correlated to age but MMA not to sex. MMA was inversely correlated to serum cobalamin but not to serum folate, whereas serum tHcy was inversely correlated to serum cobalamin, folate and creatinine. Neither serum cobalamin, folate, MMA nor tHcy had any significant correlation to haemoglobin, erythrocyte volume fraction (EVF) or mean red cell volume. Half of the study population had abnormal MMA or tHcy levels, suggesting a latent or overt tissue deficiency of cobalamin or folate. CONCLUSIONS: A substantial proportion of the elderly general population had signs of low tissue levels of cobalamin or folate. Amongst those who took multivitamin preparations this proportion was much lower.     

Absence of luminal intrinsic factor after gastric bypass surgery for morbid obesity

Abnormally low serum cobalamin levels (<180 pg/ml) have been observed in 154 of 429 patients (36%) at an average of 22 months (range 3–64 months) after gastric bypass surgery for morbid obesity. Twenty-four patients underwent a Schilling test and retrograde endoscopy of the bypassed gastric segment to determine the presence of intrinsic factor (IF) in gastric aspirates and in mucosal biopsies at 22±4 months after surgery. Five patients had a normal cobalamin level (405±44 pg/ml), and gastric juice intrinsic factor was present in three of them (11±7 ng/ml). Nineteen patients had a low cobalamin level (113±8 pg/ml), and gastric juice IF was found in only two subjects of this group (10 ng/ml each). Basal gastric juice IF concentration of healthy control subjects was 24±5 ng/ml. Schilling test results were normal in all five patients of the first group and in only nine patients of the group with cobalamin deficiency after surgery. To assess whether IF was present within the parietal cells of subjects with absent luminal IF, we studied gastric biopsy material of 14 patients using a well-characterized indirect immunoperoxidase method. IF was identified in fundic mucosal biopsy specimens of all 14 patients with absent gastric juice IF. We conclude that cobalamin deficiency occurs in a significant number of patients after gastric bypass and is associated with absence of gastric juice IF. We propose that this abnormality might be caused by inadequate secretion of IF from the bypassed stomach.This work was presented in part at the annual meeting of the American Gastroenterological Association, San Francisco, California, May 1986, and has appeared in abstract form (Gastroenterology 90:1533, 1986).     

中西药联合治疗DPN的临床研究

目的：观察中西药联合疗法对糖尿病周围神经病变（DPN）的治疗作用及安全性。方法：选取本院确诊为DPN患者120例,随机分为治疗组与对照组,两组均给予常规降糖治疗,治疗组在常规治疗的基础上加用甲钴胺500μg皮下注射＋糖痹宁口服治疗,对照在常规治疗的基础上仅给予甲钴胺500μg皮下注射治疗,两组均治疗8周,对比治疗前后两组正中神经、腓总神经运动神经传导速度（MNCV）、感觉神经传导速度（SNCV）改善情况,并观察治疗前后两组中医症候评分改善情况及临床疗效。结果：两组治疗后正中神经、腓总神经MNCV、SNCV均较治疗前改善,治疗组改善较对照组更为明显,差异具有统计学意义（P〈0.05）;两组治疗后中医症候评分均较治疗前改善,治疗组治疗后中医症候评分改善程度较对照组更为明显,差异具有统计学意义（P〈0.05）;治疗组治疗后总有效率明显高于对照组,差异有统计学意义（P〈0.05）。结论：甲钴胺联合糖痹宁可有效缓解DPN临床症状,疗效明显,且无明显不良反应,是治疗DPN的有效方案。     

Long-term effects of nitrous oxide anaesthesia on laboratory and clinical parameters in elderly Omani patients: a randomized double-blind study

AIMS: This study examined the long-term effects of nitrous oxide anaesthesia on serum levels of cobalamin and folate, red cell folate levels and haematological parameters, and neurological status in elderly Omani patients. METHODS: Sixty-nine consecutive patients undergoing ophthalmic surgery were randomly and double-blind assigned to nitrous oxide or propofol anaesthesia. They met the following entry criteria: age 55 years or above, no major organ failure, no clinical signs or symptoms of cobalamin or folate deficiency, mean cell volume (MCV) cobalamin and/or folate substitution therapy during the preceding months. Serum levels of cobalamin and folate, red cell folate levels, and haematological parameters were measured prior to anaesthesia and 3-5 weeks later. At that time, the patients also underwent thorough neurological examination. RESULTS: Data of 51 patients were complete and considered for analysis. In both nitrous oxide and propofol group, the range of exposure time was comparable (+/-1 h). In the nitrous oxide group, a slight but significant decrease in haemoglobin, Hct, and red blood cell count (RBC) (P < 0.001) was observed, whereas there was a mild increase in mean cell haemoglobin (MCH) and mean cell volume (P < 0.05). In addition, there was a significant decrease in serum folate levels (P < 0.05). Hct and RBC decreased slightly in the propofol group (P < 0. 05), whereas there was a small increase in MCH. There was no difference between the two anaesthetics with regard to serum cobalamin and red cell folate levels, but there was a significant decrease in serum folate levels in the nitrous oxide group compared to those in the propofol group. Three patients with pre-existing low red cell folate levels, who were randomized to nitrous oxide anaesthesia, developed clinical symptoms of folate deficiency. CONCLUSION: This study showed that short-term (40-80 min) nitrous oxide anaesthesia did not affect cobalamin levels but reduced serum folate levels in this elderly population. Although this reduction was clinically irrelevant, some patients with pre-existing asymptomatic folate deficiency developed nitrous oxide-induced folate deficiency.     

Causal Effects of Homocysteine,Folate, and Cobalamin on Kidney Function: A Mendelian Randomization Study

Blood homocysteine level and related vitamin levels are associated with various health outcomes. We aimed to assess causal effects of blood homocysteine, folate, and cobalamin on kidney function in the general population by performing Mendelian randomization (MR) analysis. Genetic instruments for blood homocysteine, folate, and cobalamin levels were introduced from a previous genome-wide association (GWAS) meta-analysis of European individuals. Summary-level MR analysis was performed for the estimated glomerular filtration rate (eGFR) from the CKDGen consortium GWAS that included 567,460 European ancestry individuals. For replication, allele-score-based MR was performed with an independent U.K. Biobank cohort of 337,138 individuals of white British ancestry. In summary-level MR for the CKDGen data, high genetically predicted homocysteine levels were significantly associated with low eGFR (per 1 standard deviation, beta for eGFR change −0.95 (−1.21, −0.69) %), supported by pleiotropy-robust MR sensitivity analysis. Genetically predicted high folate levels were significantly associated with high eGFR change (0.86 (0.30, 1.42) %); however, causal estimates from cobalamin were nonsignificant (−0.11 (−0.33, 0.11) %). In the U.K. Biobank data, the results were consistently identified. Therefore, a high blood homocysteine level causally decreases eGFR. Future trials with appropriate homocysteine-lowering interventions may be helpful for the primary prevention of kidney function impairment.     

Magnetic resonance imaging of subacute myelopathy due to cobalamin deficiency

A 77-year-old woman presented with rapidly ascending sensory ataxia. Magnetic resonance imaging (MRI) showed extensive involvement of the dorsal columns of the spinal cord. Hematological data were normal despite severe cobalamin deficiency. The contribution of magnetic resonance imaging in subacute degeneration of the spinal cord is discussed.     

Diversity in rat tissue accumulation of vitamin B12 supports a distinct role for the kidney in vitamin B12 homeostasis.

BACKGROUND: Vitamin B(12) in plasma is complexed to the carrier proteins transcobalamin (TC) and haptocorrin. The TC-B(12) complex is filtered in the glomeruli and reabsorbed in the renal tubules by receptor-mediated endocytosis, providing a route for a significant renal accumulation of vitamin B(12). The present study investigates the role of the rodent kidney in B(12) homeostasis by examining the distribution of vitamin B(12) in rats during vitamin B(12) depletion or B(12) load, and compares kidney accumulation with the vitamin distribution in other tissues including brain, liver, testes, intestine, spleen and plasma. METHODS: Fifteen rats were fed on a diet containing different concentrations of B(12) supplemented with s.c. injections of B(12). Twenty four hours prior to sacrifice, all animals were injected with [(57)Co]B(12). The vitamin contents of kidneys, liver, spleen, brain, testis, intestine, skeletal muscle, serum and urine were analysed. Both total tissue vitamin B(12) accumulation and [(57)Co]B(12) were determined to compare steady-state B(12) and the distribution of an acutely injected dose. In the kidney, free and protein-bound B(12) was determined by gel filtration. RESULTS: The rat kidneys accumulated more B(12) during normal and loaded conditions than any other tissue. A 110-fold increase in vitamin content was observed from the deficient to the loaded conditions in the kidney compared with a 3.5-fold increase in the liver. In contrast to all other organs, significantly smaller amounts of acutely injected B(12) accumulated in the kidneys in the vitamin-deprived state compared with both the normal and the vitamin-loaded condition. CONCLUSIONS: The present study suggests a significant role for the rodent kidney in vitamin B(12) metabolism. We propose a model for rat tissue uptake consistent with the presence of two different TC-B(12) receptors and renal uptake following filtration of TC-B(12) in the glomeruli. The presented model allows for the reduced renal uptake and accumulation in vitamin-deprived conditions, thus reserving the vitamin for other tissues, including nerve tissue and bone marrow, which are more sensitive to vitamin B(12) deficiency.     

Serum transferrin receptor in the megaloblastic anemia of cobalamin deficiency.

In order to further study the relation between transferrin receptor and erythropoiesis we examined serum receptor levels in megaloblastic anemia, which is the classic example of ineffective erythropoiesis. We studied 33 patients with unequivocal cobalamin deficiency, only 22 of whom were anemic. High serum transferrin receptor levels were found in 12 patients, all of whom were anemic and had high lactate dehydrogenase (LDH) levels; in contrast, only 10 of the 21 patients with normal receptor levels were anemic. Receptor correlated most strongly with LDH (r = 0.573, p < 0.001) and, inversely, with hemoglobin values (r = -0.560, p < 0.001); it also correlated with ferritin and total bilirubin levels, but not with cobalamin, MCV or erythropoietin. No association was found with the hemolytic component of megaloblastic anemia, represented indirectly by haptoglobin levels. Changes induced by cobalamin therapy were also examined in 13 patients. Transferrin receptors rose in all 6 patients who initially had high levels and in 2 of 3 patients who had borderline levels, but not in the 4 patients with initially normal levels. The receptor levels began to rise within 1-3 days, peaked at about 2 weeks and returned to normal at about the 5th wk. The findings indicate that serum transferrin receptor levels reflect the severity of the megaloblastic anemia. The elevated receptor levels rise further with cobalamin therapy, however, as effective erythropoiesis replaces ineffective erythropoiesis, and these persist until the increased erythropoiesis returns to normal.