Assessment of 3-epi-25-OH-D3 in preterm and full term infant samples and its relationship to demographic, anthropometric and biochemical determinants

Gestational vitamin D and offspring risk of multiple sclerosis: a systematic review and meta-analysis

PURPOSE

Our objective was to systematically review and meta-analyze studies that assessed the association between gestational vitamin D levels and risk of multiple sclerosis (MS) in offspring.

METHODS

Embase and Pubmed databases were searched from inception to May 2018. Original, observational studies that investigated both clinically defined MS (in offspring) and vitamin D levels in utero or shortly after birth were included. Two reviewers independently abstracted data and assessed the quality of studies using the Newcastle-Ottawa Quality Assessment Scale. Summary effect estimates and 95% confidence intervals were calculated with random effects models using inverse variance weighting. Determinants of heterogeneity were evaluated.

RESULTS

Four case-control studies of moderate to low risk of bias were included. Summary effect estimates of the effect of higher levels of gestational vitamin D on risk of offspring MS demonstrated a significant protective effect in random effects (OR: 0.63, 95% CI: 0.47, 0.84) models and in a stratified analysis based on study quality. Factors identified as determinants of heterogeneity were the definitions of vitamin D deficiency, the characteristics of study participants, and the quality of the study.

CONCLUSIONS

Sufficient levels of vitamin D during pregnancy may be protective against offspring's development of multiple sclerosis later in life.

Comparison of serum 25-hydroxyvitamin D levels between radioimmunoassay and liquid chromatography-tandem mass spectrometry in infants and postpartum women

Background Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has become the gold standard for the measurement of serum 25-hydroxyvitamin D (25(OH)D) levels instead of the conventional method, radioimmunoassay (RIA). However, there was no study that compared RIA and LC-MS/MS for measuring serum 25(OH)D levels in infants and their mothers. The aim of this study was to assess the agreement of RIA and LC-MS/MS for measuring the serum levels in infants and postpartum women. Methods This study enrolled 70 preterm infants, 113 term infants (134 samples), and 120 postpartum women. Serum concentration of 25(OH)D was measured by RIA and LC-MS/MS. We evaluated the correlation between RIA and LC-MS/MS. Also, we evaluated the bias between RIA and LC-MS/MS using Bland-Altman analysis. Results Sixty percent of preterm infants had serum 25(OH)D levels below the lower limit of quantification (LOQ) (4 ng/mL) and 90% of them were classified as vitamin D deficient. The serum 25(OH)D levels measured by RIA were significantly correlated with those measured by LC-MS/MS in all groups. According to the Bland-Altman plot, the serum 25(OH)D levels of infants measured by RIA had constant positive bias (mean±standard deviation [SD] [95% confidence interval, CI], preterm: +4.8± 2.4 ng/mL [4.2-5.4], term: +5.8±4.0 [5.1-6.5]) and proportional bias (preterm: r=0.44, p<0.01, term: r=0.50, p<0.01) compared with LC-MS/MS. The serum 25(OH)D levels of postpartum women measured by RIA had constant positive bias compared with LC-MS/MS, but no proportional bias was found. Conclusions RIA demonstrated falsely high 25(OH)D levels when used for infants and postpartum women.

Placental vitamin D metabolism and its associations with circulating vitamin D metabolites in pregnant women

Background: Little is known about placental vitamin D metabolism and its impact on maternal circulating vitamin D concentrations in humans.Objective: This study sought to advance the current understanding of placental vitamin D metabolism and its role in modulating maternal circulating vitamin D metabolites during pregnancy.Design: Nested within a feeding study, 24 healthy pregnant women (26-29 wk of gestation) consumed a single amount of vitamin D (511 IU/d from diet and a cholecalciferol supplement) for 10 wk. Concentrations of placental and blood vitamin D metabolites and placental messenger RNA (mRNA) abundance of vitamin D metabolic pathway components were quantified. In addition, cultured human trophoblasts were incubated with ¹³C-cholecalciferol to examine the intracellular generation and secretion of vitamin D metabolites along with the regulation of target genes.Results: In placental tissue, 25-hydroxyvitamin D₃ [25(OH)D₃] was strongly correlated (r = 0.83, P < 0.001) with 24,25-dihydroxyvitamin D₃ Moreover, these placental metabolites were strongly correlated (r ≤ 0.85, P ≤ 0.04) with their respective metabolites in maternal circulation. Positive associations (P ≤ 0.045) were also observed between placental mRNA abundance of vitamin D metabolic components and circulating vitamin D metabolites [i.e., LDL-related protein 2 (LRP2, also known as megalin) with 25(OH)D₃ and the C3 epimer of 25(OH)D₃ [3-epi-25(OH)D₃]; cubilin (CUBN) with 25(OH)D₃; 25-hydroxylase (CYP2R1) with 3-epi-25(OH)D₃; 24-hydroxylase (CYP24A1) with 25(OH)D₃, 3-epi-25(OH)D₃, and 1,25-dihydroxyvitamin D₃ [1,25(OH)₂D₃]; and 1α-hydroxylase [(CYP27B1) with 3-epi-25(OH)D₃ and 1,25(OH)₂D₃]. Notably, in vitro experiments with trophoblasts showed increased production and secretion of 25(OH)D₃ and higher CYP24A1 gene transcript abundance in response to cholecalciferol treatment.Conclusions: The numerous associations of many of the placental biomarkers of vitamin D metabolism with circulating vitamin D metabolites among pregnant women [including a CYP27B1-associated increase in 1,25(OH)₂D₃] and the evidence of trophoblast production and secretion of vitamin D metabolites, especially 25(OH)D₃, suggest that the placenta may play an active role in modulating the vitamin D metabolite profile in maternal circulation in human pregnancy. This trial was registered at clinicaltrials.gov as NCT03051867.

The Road Not So Travelled: Should Measurement of Vitamin D Epimers during Pregnancy Affect Our Clinical Decisions?

Observational studies suggest an adverse effect of maternal hypovitaminosis D during pregnancy. However, intervention studies failed to show convincing benefit from vitamin D supplementation during pregnancy. With analytical advances, vitamin D can now be measured in ten forms—including as epimers—which were thought to be biologically inactive, but can critically impair immunoassays. The aim of this commentary is to highlight the potential clinical and analytical significance of vitamin D epimers in the interpretation of vitamin D roles in pregnancy. Epimers may contribute a considerable proportion of total vitamin D—especially in the neonate—which renders the majority of common assays questionable. Furthermore, epimers have been suggested to have activity in laboratory studies, and evidence suggests that the fetus contributes significantly to epimer production. Maternal epimer levels contribute significantly to predict neonate circulating 25-hydroxyvitamin D concentrations. In conclusion, the existence of various vitamin D forms (such as epimers) has been established, and their clinical significance remains obscure. These results underscore the need for accurate measurements to appraise vitamin D status, in order to understand the current gap between observational and supplementation studies on the field.

Assessment of 3-epi-25-hydroxyvitamin D levels during cholecalciferol supplementation in adults with chronic liver diseases

Recently, hepatic immaturity was cited as a possible reason for high levels of the C-3 epimer of 25-hydroxyvitamin (25(OH)D) in premature infants: however what role, if any, the liver plays in controlling epimer concentrations is unknown. This study assesses 3-epi-25-hydroxyvitamin D (3-epi-25(OH)D) levels during the course of cholecalciferol supplementation in adults with chronic liver diseases (CLD). Vitamin D metabolites were analyzed in 65 CLD patients with 25(OH)D <30 ng/mL who received 20 000 IU cholecalciferol/week for 6 months. The primary outcome assessed serum 25(OH)D and 3-epi-25(OH)D in response to supplementation. Corresponding values from 16 CLD patients with sufficient vitamin D levels receiving no supplementation were compared. The epimer was detected in all samples and at lower relative concentrations with lower vitamin D baseline status, i.e., severe vitamin D deficiency (<10 ng/mL) as compared with deficient (10–19.9 ng/mL), insufficient (20–29.9 ng/mL), or sufficient (≥30 ng/mL) vitamin D levels (2.4% vs. 4.8%, 5.2%, 5.8%, respectively; P < 0.001). Similar relative concentrations for 3-epi-25(OH)D, ranging from 4.3%–7.1% (absolute concentrations: 1.1–4.0 ng/mL; all P < 0.001), were obtained in response to cholecalciferol in all supplemented patients, regardless of inadequacy threshold. Epimer levels significantly decreased (P = 0.007) in unsupplemented patients, coinciding with decreasing serum 25(OH)D concentrations over time. No epimer differences between patients with (n = 17) or without (n = 48) cirrhosis were demonstrated. The 3-epi-25(OH)D was present in serum of all patients at comparable levels to those reported by others. Epimer levels increased linearly with increasing 25(OH)D levels after supplementation. However, no effect of cirrhosis on epimer concentrations was observed.

Vitamin D status in mothers with pre-eclampsia and their infants: a case-control study from Serbia, a country without a vitamin D fortification policy

OBJECTIVE

The objective of the present study was to determine if vitamin D intake and status are associated with pre-eclampsia in a country without a vitamin D fortification policy.

DESIGN

A case-control study of pregnancies with (case) and without (control) pre-eclampsia was conducted from January to April when UVB is minimal. Maternal and cord blood obtained at delivery were measured for plasma 25-hydroxycholecalciferol (25-OH-D3), 3-epimer of 25-OH-D3 (3-epi-25-OH-D3) and 24,25-dihydroxycholecalciferol (24,25-(OH)2D3) by LC-MS/MS and maternal 1,25-dihydroxyvitamin D (1,25-(OH)2D). Differences between groups were tested with ANOVA and Bonferroni post hoc tests (P<0·05).

SETTING

Clinical Center of Serbia.

SUBJECTS

Pregnant women with and without pre-eclampsia (n 60) and their infants.

RESULTS

Exogenous vitamin D intake (0·95-16·25 µg/d (38-650 IU/d)) was not significantly different between groups. Women with pre-eclampsia delivered infants at an earlier gestational age and had significantly lower mean total plasma 25-hydroxyvitamin D (25-OH-D; case: 11·2 (sd 5·1); control: 16·1 (sd 5·7) ng/ml; P=0·0006), 25-OH-D3 (case: 10·0 (sd 4·9); control: 14·2 (sd 5·8) ng/ml; P=0·002), 3-epi-25-OH-D3 (case: 0·5 (sd 0·2); control: 0·7 (sd 0·2) ng/ml; P=0·0007) and 1,25-(OH)2D (case: 56·5 (sd 26·6); control: 81·0 (sd 25·7) pg/ml; P=0·018), while 24,25-(OH)2D3 was not different between groups. Infants did not differ in total plasma 25-OH-D, 25-OH-D3, 3-epi-25-OH-D3 and 24,25-(OH)2D3, but the mean proportion of 3-epi-25-OH-D3 was higher in the infant case group (case: 7·9 (sd 1·1); control: 7·0 (sd 1·4) % of total 25-OH-D3; P=0·005).

CONCLUSIONS

A high prevalence of vitamin D deficiency, as defined by plasma 25-OH-D<12 ng/ml, was observed in 47 % of all mothers and 77 % of all infants. These data underscore the need for prenatal vitamin D supplementation and a food fortification policy in Serbia.

Time-course analysis of 3-epi-25-hydroxyvitamin D3 shows markedly elevated levels in early life, particularly from vitamin D supplementation in preterm infants

BACKGROUND

An epimeric form of 25-hydroxyvitamin D3 (25(OH)D3) has recently been detected in clinical samples, with relatively high levels in infants. Little is known on 3-epi-25(OH)D3 formation and physiological function. Our objective was to study dynamics of 3-epi-25(OH)D3 formation during infancy.

METHODS

25(OH)D3 and 3-epi-25(OH)D3 levels were measured by liquid chromatography-tandem mass spectrometry in 22 preterm (aged 34-37 wk), 15 early preterm (aged <34 wk), and 118 term infants up to 2 y of age. All infants were prescribed vitamin D 400 IU/day after the first week of life.

RESULTS

At birth, 3-epi-25(OH)D3 levels were 3 (1-7) nmol/l, <10% of total 25(OH)D3. From the second week to 3 mo of age, both 25(OH)D3 and 3-epi-25(OH)D3 increased, with highest 3-epi-25(OH)D3 contribution in early preterm infants (up to 55% of total 25(OH)D3 vs. 36% in term infants, P < 0.0001). After 3 mo of age, 3-epi-25(OH)D3 normalized to <10% in all infants.

CONCLUSIONS

At birth, all infants showed low contribution of 3-epi-25(OH)D3, increasing the week after starting vitamin D supplementation, until 3 mo of age. Highest levels of 3-epi-25(OH)D3 were found in early preterm infants, supporting the hypothesis that hepatic immaturity plays a role in 3-epi-25(OH)D3 formation.