A High-Throughput Platform for the Rapid Screening of Vitamin D Status by Direct Infusion-Tandem Mass Spectrometry

Treatment response variations to a single large bolus of enteral cholecalciferol in vitamin D deficient critically Ill children: Metabolomic insights for precision nutrition

Vitamin D deficiency (VDD) is prevalent globally and in pediatric intensive care units, where it represents a modifiable risk factor that may impact patient recovery during hospitalization. Herein, we performed a retrospective analysis of serum samples from a phase-II randomized placebo-controlled trial involving a single large bolus of 10,000 IU/kg vitamin D3 ingested by critically ill children with VDD (25-OH-D < 50 nmol/L). Targeted and untargeted methods were used to comprehensively measure 6 vitamin D metabolites, 239 lipids, 68 polar metabolites, and 4 electrolytes using a multi-step data workflow for compound authentication. Complementary statistical methods classified circulating metabolites/lipids associated with vitamin D repletion following high-dose vitamin D3 intake (n = 20) versus placebo (n = 11) comprising an optional standard of care maintenance dose (< 1000 IU/day). There was a striking increase in median serum concentrations of 25-OH-D3 (4.7-fold), 3-epi-25-OH-D3 (24-fold) and their C3-epimer ratio (6.7-fold) in treated patients on day 3, whereas serum vitamin D3 peaked on day 1 (128-fold) unlike placebo. Treatment response differences were attributed to D3 bioavailability and C3-epimerase activity without evidence of hypercalcemia. For the first time, we report the detection of circulating 3-epi-D3 that was strongly correlated with vitamin D3 uptake (r = 0.898). Metabolomic studies revealed that vitamin D sufficiency (serum 25-OH-D >75 nmol/L) coincided with lower circulating levels of 3-methylhistidine, cystine, S-methylcysteine, uric acid, and two lysophosphatidylcholines 7 days after treatment. Rapid correction of VDD was associated with indicators of lower oxidative stress, inflammation, and muscle protein turn-over that may contribute clinical benefits in high-risk critically ill children.

Rapid normalization of vitamin D deficiency in PICU (VITdALIZE-KIDS): study protocol for a phase III, multicenter randomized controlled trial

BACKGROUND

The rate of vitamin D deficiency (VDD) in critically ill children worldwide has been estimated at 50%. These children are at risk of multiple organ dysfunction, chronic morbidity, and decreased health related quality of life (HRQL). Pediatric and adult ICU clinical trials suggest that VDD is associated with worse clinical outcomes, although data from supplementation trials are limited and inconclusive. Our group's phase II multicenter dose evaluation pilot study established the efficacy and safety of an enteral weight-based cholecalciferol loading dose to rapidly restore vitamin D levels in critically ill children.

METHODS

Our aim is to evaluate the impact of this dosing regimen on clinical outcomes. VITdALIZE-KIDS is a pragmatic, phase III, multicenter, double-blind RCT aiming to randomize 766 critically ill children from Canadian PICUs. Participants are randomized using a 1:1 scheme to receive a single dose at enrollment of enteral cholecalciferol (10,000 IU/kg, max 400,000 IU) or placebo. Eligibility criteria include critically ill children aged newborn (> 37 weeks corrected gestational age) to < 18 years who have blood total 25-hydroxyvitamin D < 50 nmol/L. The primary objective is to determine if rapid normalization of vitamin D status improves HRQL at 28 days following enrollment. The secondary objective is to evaluate the impact of rapid normalization of vitamin D status on multiple organ dysfunction. The study includes additional tertiary outcomes including functional status, HRQL and mortality at hospital discharge and 90 days, PICU and hospital length of stay, and adverse events related to vitamin D toxicity. Additionally, we are performing comprehensive vitamin D speciation and non-targeted metabolite profiling as part of a sub-study for the first 100 participants from whom an enrollment and at least one post-intervention blood and urine sample were obtained.

DISCUSSION

The VITdALIZE-KIDS trial is the first phase III, multicenter trial to evaluate whether rapid normalization of vitamin D status could represent a simple, inexpensive, and safe means of improving outcomes following pediatric critical illness. Recruitment was initiated in June 2019 and is expected to continue to March 2026.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT03742505. Study first submitted on November 12, 2018 https://clinicaltrials.gov/study/NCT03742505.

Accurate Clinical Detection of Vitamin D by Mass Spectrometry: A Review

Vitamin D deficiency is thought to be associated with a wide range of diseases, including diabetes, cancer, depression, neurodegenerative diseases, and cardiovascular and cerebrovascular diseases. This vitamin D deficiency is a global epidemic affecting both developing and developed countries and therefore qualitative and quantitative analysis of vitamin D in a clinical context is essential. Mass spectrometry has played an increasingly important role in the clinical analysis of vitamin D because of its accuracy, sensitivity, specificity, and the ability to detect multiple substances at the same time. Despite their many advantages, mass spectrometry-based methods are not without analytical challenges. Front-end and back-end challenges such as protein precipitation, analyte extraction, derivatization, mass spectrometer functionality, must be carefully considered to provide accurate and robust analysis of vitamin D through a well-designed approach with continuous control by internal and external quality control. Therefore, the aim of this review is to provide a comprehensive overview of the development of mass spectrometry methods for vitamin D accurate analysis, including emphasis on status markers, deleterious effects of biological matrices, derivatization reactions, effects of ionization sources, contribution of epimers, standardization of assays between laboratories.

To metabolomics and beyond: a technological portfolio to investigate cancer metabolism

Tumour cells have exquisite flexibility in reprogramming their metabolism in order to support tumour initiation, progression, metastasis and resistance to therapies. These reprogrammed activities include a complete rewiring of the bioenergetic, biosynthetic and redox status to sustain the increased energetic demand of the cells. Over the last decades, the cancer metabolism field has seen an explosion of new biochemical technologies giving more tools than ever before to navigate this complexity. Within a cell or a tissue, the metabolites constitute the direct signature of the molecular phenotype and thus their profiling has concrete clinical applications in oncology. Metabolomics and fluxomics, are key technological approaches that mainly revolutionized the field enabling researchers to have both a qualitative and mechanistic model of the biochemical activities in cancer. Furthermore, the upgrade from bulk to single-cell analysis technologies provided unprecedented opportunity to investigate cancer biology at cellular resolution allowing an in depth quantitative analysis of complex and heterogenous diseases. More recently, the advent of functional genomic screening allowed the identification of molecular pathways, cellular processes, biomarkers and novel therapeutic targets that in concert with other technologies allow patient stratification and identification of new treatment regimens. This review is intended to be a guide for researchers to cancer metabolism, highlighting current and emerging technologies, emphasizing advantages, disadvantages and applications with the potential of leading the development of innovative anti-cancer therapies.

Stability of sample extracts of vitamin D3 metabolites after chemical derivatization for LC-MS/MS analysis

Liquid chromatography/tandem mass spectrometry (LC-MS/MS) is widely used to determine vitamin D₃ metabolites in biological samples. The ionization efficiencies of these metabolites, however, are poor under electrospray ionization conditions. Moreover, the chromatographic separation of multiple vitamin D metabolites and their epimers can be challenging. For these reasons, chemical derivatization reagents are often used to improve sensitivity and selectivity of analysis. While the derivatization schemes have been proven to be very effective, one missing aspect is the investigation of the stability of the chemical derivatization products in stored sample extracts. In this study, we investigated the long-term stability of several vitamin D₃ metabolites after 1 and 3 months of storage at - 20 °C. Five vitamin D₃ metabolites were examined after derivatization with seven different derivatization reagents. Generally, Amplifex products were the most stable in the long term in our study with 11-20% degraded after 1 month of storage and 14-35% after 3 months. The stabilities for some of the metabolites' 4-[2-(6,7-dimethoxy-4-methyl-3-oxo-3,4-dihydroquinoxalyl)ethyl]-1,2,4-triazoline-3,5-dione (DMEQ-TAD), 2-fluoro-1-methylpyridinium p-toluenesulfonate (FMP-TS), isonicotinoyl chloride (INC) and 4-phenyl-1,2,4-triazoline-3,5-dione acetylated (PTAD-Ac) products were also acceptable after 1 month of storage. Other derivatized metabolites, however, degraded extensively already after 1 month of storage, such as 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) (54-72% degradation) and 2-nitrosopyridine (PyrNO) (32-100% degradation). Importantly, for every metabolite, there was an optimum derivatization reagent that met the criteria of stability proposed by international regulatory bodies after 1 month of storage. Some derivatives were stable for even up to 3 months of storage, with degradation of less than 15%.