Cobalamin related parameters and disease patterns in patients with increased serum cobalamin levels

Paradoxical increase of plasma vitamin B12 and folates with disease severity in anorexia nervosa

OBJECTIVE

Anorexia nervosa (AN) is a complex disorder involving severe psychological manifestations and multiple organ damage, including liver dysfunction. The primary aim of this study consisted in assessing plasma levels of vitamin B12 and folates with respect to liver function enzymes considering the liver-storage properties of this vitamin.

METHOD

We recruited 70 restrictive type AN adolescents and the severity of psychopathological traits was assessed using EDI-3 scale. Plasma levels of vitamin B12 , folates, transaminases (AST, ALT), gamma-glutamyl transpeptidase (GGT), alkaline phosphatase (ALP) and cholinesterase (CHE) were determined.

RESULTS

About 38.5% of patients displayed vitamin B12 values (H-B12) above the upper range of normal reference; 4.3% of patients had increased values of folates; 20 and 11.4% of patients displayed ALT and AST values above reference limits; none had GGT values above normal range. Albeit low CHE and ALP values were found in 55 and 20% of patients, respectively, a linear correlation with both transaminases was present only for vitamin B12 and folates; furthermore, H-B12 patients had both higher AST and ALT values. EDI- 3 subscores significantly correlated with vitamin B12 and folates plasma values and H-B12 patients displayed EDI-3 higher values.

DISCUSSION

These data suggest that plasma levels of vitamin B12 might be an early marker of liver dysfunction, possibly also related to more severe psychopathological aspects. The identification of patients with higher fasting plasma vitamin B12 levels could therefore lead to earlier and more careful refeeding interventions. Further studies will clarify the potential role of this vitamin in AN clinical practice.

Hypercobalaminaemia is associated with hepatic and neoplastic disease in cats: a cross sectional study

Background

When increased serum cobalamin concentrations are encountered clinically they are usually attributed to parenteral supplementation, dietary factors, or otherwise ignored. However, recently, hypercobalaminaemia has been associated with numerous diseases in humans, most notably neoplastic and hepatic disorders. The aim of this retrospective, observational, cross-sectional study was to determine the significance of increased cobalamin in cats.

Results

In total, 237 records were retrieved and 174 cats, of various ages and sexes met the inclusion criteria. A total of 42 cats had increased serum cobalamin concentration, and had not received prior supplementation. Multiple logistic regression analysis revealed that increased serum cobalamin concentration was positively related to pedigree breed (pedigree breeds more likely to have increased cobalamin concentration, odds ratio [OR] 4.24, 95% CI 1.78-10.15, P = 0.001), to having liver disease (OR 9.91, 95% CI 3.54-27.68), and to having a solid neoplasm (OR 8.54, 95% CI 1.10-66.45).

Conclusions

The results of the current study suggest that increased serum cobalamin concentrations should not be ignored in cats with no history of supplementation, and investigation for underlying hepatic or neoplastic disease is warranted.

High vitamin B12 levels are not associated with increased mortality risk for ICU patients after adjusting for liver function: a cohort study

BACKGROUND AND AIMS

Recent research has suggested that high vitamin B12 levels may be associated with increased mortality after ICU admission. However, it is known that impaired liver function may lead to elevated B12 since B12 is metabolized through the liver, and therefore high B12 levels may serve as a proxy for poor liver function. The aim of this study is to assess the impact that liver function and liver disease have on the relationship between high vitamin B12 levels and mortality in the ICU.

METHODS

We performed an observational cohort study using ICU data that were collected from patients admitted to four ICU types (medical, surgical, cardiac care and cardiac surgery recovery) in one large urban hospital from 2001 to 2008. We analyzed the medical records of 1,684 adult patients (age ≥ 18 years) who had vitamin B12 and liver function measurements up to 14 days prior to ICU admission or within 24 hours after admission.

RESULTS

While we found an association between high B12 and mortality when we did not control for any potential confounders, after we adjusted for liver function and liver disease, no significant association existed between B12 and mortality using multivariable logistic regression (30-day mortality: OR=1.18, 95% CI 0.81 to 1.72, p=0.3890; 90-day mortality: OR=1.20, 95% CI 0.84 to 1.71, p=0.3077).

CONCLUSIONS

Elevated B12 levels are not a significant predictor of mortality after ICU admission when liver function is controlled for, and may instead be a proxy for poor liver function.

Vitamin B12 supplement alleviates N'-nitrosodimethylamine-induced hepatic fibrosis in rats

Abstract Context: Altered vitamin B12 levels have been correlated with hepatotoxicity; however, further evidence is required to establish its protective role. Objective: To evaluate the effects of vitamin B12 supplement in protecting N'-nitrosodimethylamine (NDMA)-induced hepatic fibrosis in Wistar rats. Materials and methods: Hepatic fibrosis was induced by administering NDMA in doses of 10 mg/kg body weight thrice a week for 21 days. Another group received equal doses (10 mg/kg body weight) of vitamin B12 subsequent to NDMA treatment. Animals from either group were sacrificed weekly from the start of the treatment along with their respective controls. Progression of hepatic fibrosis, in addition to the effect of vitamin B12, was assessed biochemically for liver function biomarkers, liver glycogen, hydroxyproline (HP) and B12 reserves along with histopathologically by hematoxylin and eosin (H & E) as well immunohistochemical staining for α-SMA expression. Results and discussion: Elevation in the levels of aminotransferases, SALP, total bilirubin and HP was observed in NDMA treated rats, which was concomitant with remarkable depletion in liver glycogen and B12 reserves (p < 0.05). Liver biopsies also demonstrated disrupted lobular architecture, collagen amassing and intense fibrosis by NDMA treatment. Immunohistochemical staining showed the presence of activated stellate cells that was dramatically increased up to day 21 in fibrotic rats. Following vitamin B12 treatment, liver function biomarkers, glycogen contents and hepatic vitamin B12 reserves were restored in fibrotic rats, significantly. Vitamin B12 administration also facilitated restoration of normal liver architecture. Conclusion: These findings provide interesting new evidence in favor of protective role for vitamin B12 against NDMA-induced hepatic fibrosis in rats.

Elevated plasma vitamin B12 levels as a marker for cancer: a population-based cohort study

BACKGROUND

A substantial proportion of patients referred for plasma vitamin B12 (cobalamin [Cbl]) measurement present with high Cbl levels, which have been reported in patients with different cancer types. However, the cancer risk among patients with newly diagnosed high Cbl levels has not been adequately examined.

METHODS

We conducted this cohort study using population-based Danish medical registries. Patients referred for Cbl measurement with levels greater than the lower reference limit (≥200 pmol/L) were identified from the population of Northern Denmark during the period of 1998 to 2009 using a database of laboratory test results covering the entire population. Data on cancer incidence (follow-up 1998-2010), Cbl treatment, and prior diagnoses were obtained from medical registries. Patients receiving Cbl treatment were excluded. Cancer risks were calculated as standardized incidence ratios (SIRs) with 95% confidence intervals (CIs), stratified by plasma Cbl levels. All statistical tests were two-sided.

RESULTS

We identified 333 667 persons without prevalent cancer and not receiving Cbl treatment. Six percent had Cbl levels greater than the upper reference limit (≥601 pmol/L). Cancer risk increased with higher Cbl levels and was highest during the first year of follow-up (Cbl 601-800 pmol/L: SIR = 3.44, 95% CI = 3.14 to 3.76; Cbl >800 pmol/L: SIR = 6.27, 95% CI = 5.70 to 6.88; both P < .001). The risks were particularly elevated for hematological and smoking- and alcohol-related cancers for persons with high Cbl levels.

CONCLUSIONS

High Cbl levels were associated with the risk of subsequently diagnosed cancer, mostly within the first year of follow-up. This may have clinical implications for the interpretation of high Cbl levels.

The soluble receptor for vitamin B12 uptake (sCD320) increases during pregnancy and occurs in higher concentration in urine than in serum

Background

Cellular uptake of vitamin B₁₂ (B12) demands binding of the vitamin to transcobalamin (TC) and recognition of TC-B12 (holoTC) by the receptor CD320, a receptor expressed in high quantities on human placenta. We have identified a soluble form of CD320 (sCD320) in serum and here we present data on the occurrence of this soluble receptor in both serum and urine during pregnancy.

Methods

We examined serum from twenty-seven pregnant women (cohort 1) at gestational weeks 13, 24 and 36 and serum and urine samples from forty pregnant women (cohort 2) tested up to 8 times during gestational weeks 17-41. sCD320, holoTC, total TC and complex formation between holoTC and sCD320 were measured by in-house ELISA methods, while creatinine was measured on the automatic platform Cobas 6000. Size exclusion chromatography was performed on a Superdex 200 column.

Results

Median (range) of serum sCD320 increased from 125 (87-839) pmol/L (week 15) to reach a peak value of 199 (72-672) pmol/L (week 35) then dropped back to its baseline level just before birth (week 40). Around one third of sCD320 was precipitated with holoTC at all-time points studied. The urinary concentration of sCD320 was around two fold higher than in serum. Urinary sCD320/creatinine ratio correlated with serum sCD320 and reached a peak median level of 53 (30–101) pmol/mmol creatinine (week 35). sCD320 present in serum and urine showed the same elution pattern upon size exclusion chromatography.

Conclusion

We report for the first time that sCD320 is present in urine and in a higher concentration than in serum and that serum and urine sCD320 increase during pregnancy. The high urinary concentration and the strong correlation between urinary and serum sCD320 suggests that sCD320 is filtered in the kidney.

Laboratory testing for cobalamin deficiency in megaloblastic anemia

Cobalamin (vitamin B12) deficiency is a common cause of megaloblastic anemia in Western populations. Laboratory evaluation of megaloblastic anemia frequently includes the assessment of patient cobalamin and folate status. Current total serum cobalamin measurements are performed in the clinical laboratory with competitive binding luminescence assays, whose results may not always accurately reflect actual cobalamin stores. Surrogate markers of cobalamin deficiency such as methylmalonic acid and homocysteine have been utilized to improve diagnostic accuracy; however, the specificity of these tests by themselves is rather low. Measurement of the biologically active fraction of cobalamin, holotranscobalamin, has been proposed as a replacement for current total cobalamin assays. Although holotranscobalamin measurements appear to have slighter better sensitivity, the specificity of this assay remains to be determined. The relative merits and demerits of commonly available methods to assess cobalamin deficiency in patients with suspected megaloblastic anemia are discussed.

The pathophysiology of elevated vitamin B12 in clinical practice

Hypercobalaminemia (high serum vitamin B12 levels) is a frequent and underestimated anomaly. Clinically, it can be paradoxically accompanied by signs of deficiency, reflecting a functional deficiency linked to qualitative abnormalities, which are related to defects in tissue uptake and action of vitamin B12. The aetiological profile of high serum cobalamin predominantly encompasses severe disease entities for which early diagnosis is critical for prognosis. These entities are essentially comprised of solid neoplasms, haematological malignancies and liver and kidney diseases. This review reflects the potential importance of the vitamin B12 assay as an early diagnostic marker of these diseases. A codified approach is needed to determine the potential indications of a search for high serum cobalamin and the practical clinical strategy to adopt upon discovery of elevated cobalamin levels. While low serum cobalamin levels do not necessarily imply deficiency, an abnormally high serum cobalamin level forms a warning sign requiring exclusion of a number of serious underlying pathologies. Functional cobalamin deficiency can thus occur at any serum level.