Establishing preanalytical stability of vitamin A and vitamin E

Vitamin A and Vitamin E, a group of lipid-soluble vitamins, can be degraded by photolysis and photooxidation after exposure to light. As an essential area of the preanalytical stage, inappropriate storage conditions of patient samples could lead to inaccurate results. In this study, we evaluated three of the most common preanalytical storage conditions (RT, +4°C, and -20 °C) in the workflow in the clinical laboratory setting using both clear and amber Eppendorf tubes. Analyte stability in each storage condition was tested with five patient pools. After 24 hrs at RT, a significant decrease in vitamin A and E was observed for samples stored in clear Eppendorf tubes (19.2 % and 17.9 %, for vitamin A and E, respectively), compared with samples stored in amber Eppendorf tubes (9.1 % and 7.3 %), respectively. After the specimen was stored at 4 °C for 7 days, vitamin A concentrations decreased in clear tubes by 14.7 % and in amber tubes by 12.7 %. Similarly, vitamin E concentrations decreased in both clear and amber tubes by 11.2 % and 13.4 %, respectively. Both vitamin A and vitamin E demonstrated acceptable stability in clear and amber Eppendorf tubes at -20 °C for up to 22 days. It is preferable to use amber tubes to protect vitamin A and E from light during short term storage. Storage of vitamin A and E specimens beyond 7 days should be at -20 °C.

Lessons learned from two clinical trials on nutritional supplements to reduce aggressive behaviour

BACKGROUND

Setting up and conducting a randomised controlled trial (RCT) has many challenges-particularly trials that include vulnerable individuals with behavioural problems or who reside in facilities that focus on care as opposed to research. These populations are underrepresented in RCTs.

APPROACH

In our paper, we describe the challenges and practical lessons learned from two RCTs in two care settings involving long-stay psychiatric inpatients and people with intellectual disabilities. We describe five main difficulties and how these were overcome: (1) multisite setting, (2) inclusion of vulnerable participants, (3) nutritional supplements and placebos, (4) assessment of behavioural outcomes, and (5) collecting bio samples.

CONCLUSIONS

By sharing these practical experiences, we hope to inform other researchers how to optimally design their trials, while avoiding and minimising the difficulties that we encountered, and to facilitate the implementation of a trial. Both trials were registered in the Clinical Trials Register (RCT A: NCT02498106; RCT B: NCT03212092).

A novel LC-MS/MS method for the simultaneous analysis of selected fat-soluble vitamins in serum obtained from pediatric patients with pneumonia

Several observational studies have reported associations between low levels of fat-soluble vitamins (A, D and E) and the incidence of pneumonia. Whether infection affects or negatively regulates serum vitamin levels remains controversial. Our aims were to develop and validate a simple-pretreatment and fast method to determine the serum levels of selected fat-soluble vitamins, namely vitamin A (retinol), vitamin D (25-OH-D₃, 25-OH-D₂, and 3-epi-25-OH-D₃), and vitamin E (α-tocopherol), in children suffering from pneumonia during the acute phase and after inflammatory marker recovery. The sample preparation procedure involving protein precipitation and filtration was finished in one step, and separation took 8 min per sample. The calibrations were linear, with R² > 0.99. Both the intra-run (n = 6) and inter-run (n = 3) precision (relative standard deviation, RSD%) values were below 14.61%. The spiked recoveries at 3 concentrations ranged from 80.97 to 111.91%. Accuracies were calibrated using both National Institute of Standards and Technology serum (NIST 968f) and external quality assurance (EQA) samples offered by the National Center of Clinical Laboratories of China, and the relative error (RE%) values ranged from -13.17% to 12.53%. Clinical sample analysis revealed that infection did alter the serum retinol concentration and it did not alter the 25-OH-D and α-tocopherol levels in young children with pneumonia.

Absolute quantification of eleven A, D, E and K vitamers in human plasma using automated extraction and UHPLC-Orbitrap MS

Fat-Soluble Vitamers [FSV] deficiencies and hypervitaminosis are associated with lifestyle diseases such as cardiovascular disease, diabetes, and cancer. Quantification of FSV and their metabolites in plasma has proved to be one of the most demanding analytical chemistry challenges. Current FSV quantification methods are compromises between breadth of coverage and sensitivity across the physiological range. Here, we developed and validated a sensitive, robust, semi-automated method using liquid-liquid extraction coupled with LC-ESI-MS/MS to quantify 11 FSV across their physiological concentrations in plasma. The addition of Phree® phospholipid removal plates as the last step in the extraction process reduced matrix effects, improving precision, recoveries, and the method's final sensitivity. This method can detect and quantify: retinol, retinoic acid, retinyl palmitate, 25 hydroxyvitamin D₃ [25-OH-D₃], 1-α-25-dihydroxy-D_3, α-tocopherol, γ-tocopherol, α-tocotrienol, phylloquinone [K1], Menatetrenone [MK-4], and menaquinone-7 [MK-7].The Instrument Quantitation Limit [IQL]s for retinol (64.1 ng/mL), 25-OH-D₃ (10.2 ng/mL), and α-tocopherol (3000 ng/mL) can detect clinical deficiencies. Our automated method will assist in the understanding of the complex interaction between these compounds and their possible role in health and disease.

An Updated Comprehensive Review on Vitamin A and Carotenoids in Breast Cancer: Mechanisms, Genetics, Assessment, Current Evidence, and Future Clinical Implications

Vitamin A and carotenoids are fat-soluble micronutrients that play important role as powerful antioxidants modulating oxidative stress and cancer development. Breast cancer is the most common malignancy in women. As the risk of breast cancer is dependent on various lifestyle factors such as dietary modifications, there is increasing interest surrounding the anti-cancerous properties of vitamin A and carotenoids. Despite the suggested protective roles of vitamin A and carotenoids in breast cancer development, their clinical application for the prevention and treatment of breast cancer is limited. In this narrative review, we discuss the roles of vitamin A and carotenoids along with the evaluation method of vitamin A status. We also exhibit the association of genetic variations involved in metabolism of vitamin A and carotenoids with cancers and other diseases. We demonstrate the epidemiological evidence for the relationship of vitamin A and carotenoids with breast cancer risk, their effects on cancer mechanism, and the recent updates in clinical practice of vitamin A or carotenoids as a potential therapeutic agent against breast cancer. This review provides insight into the preventive and therapeutic roles of vitamin A and carotenoids in breast cancer development and progression.

Measurement of plasma 25-hydroxyvitamin D2, 25-hydroxyvitamin D3 and 3-epi-25-hydroxyvitamin D3 in population of patients with cardiovascular disease by UPLC-MS/MS method

Vitamin D has a potential role in protecting against cardiovascular disease (CVD). Serum 25-hydroxyvitamin D (25D) is the most widely used indicator of vitamin D status in the human body. 25D is estimated as total of 25-hydroxyvitamin D2 (25D2) and 25-hydroxyvitamin D3 (25D3). However, the presence of 3-epi-25-hydroxyvitamin D3 (3epi25D3) can affect 25D measurement. In this research a novel validated UPLC-MS/MS technique was developed to measure three vitamin D metabolites, 25D2, 25D3 and 3epi25D3 in human plasma. A liquid-liquid extraction using hexane was applied for isolation of the analytes from the samples. A chromatographic separation was achieved in a Kinetex F5 analytical column with isocratic elution (water and methanol with 0.1% methanoic acid, 20:80 v/v). Mass spectrometry detection of the metabolites was performed in a triple-quadruple tandem mass spectrometer under positive ion mode. Concentrations of the analytes were estimated in plasma samples of 54 patients. Validation parameters of the UPLC-MS/MS method, including linearity, precision, accuracy, and stability, fulfilled the requirements for bioanalytical assays. The deficient concentration of 25D (<20 ng/mL) was stated in over 60% of patients. 3epi25D3 was present in 78% of samples and its relative amount ranged from 0 to 54.1% of 25D concentration. The analysis of 25D2, 25D3 and 3epi25D3 by the validated UPLC-MS/MS method in plasma of patients with CVD permitted the classification of the patients with insufficient levels of 25D. 3epi25D3 might be relevant in the classification of vitamin D status.

LC-MS/MS quantification of fat soluble vitamers - A systematic review

Fat soluble vitamers (FSV) are several biochemically diverse micronutrients essential for healthy development, growth, metabolism, and cell regulation. We cannot synthesize FSV completely or at the required concentrations. Deficiency or excess of FSV can result in many health problems. Plasma is the most accessible sample matrix for the quantification of FSV. However, due to its complexity and other analytical challenges (e.g., FSV sensitivity to light, oxygen, heat, pH, chemical heterogeneity, standard availability), developing a method for the simultaneous quantification of multiple FSV at physiological concentrations has been challenging. In this systematic review, we examine the parameters and criteria used in existing Liquid Chromatography with tandem Mass Spectrometry (LC-MS/MS) methods for FSV quantification to the extraction method, chromatographic resolution, matrix effects, and method validation as critical to a sensitive and robust method. We conclude that the final FSV method sensitivity is predominantly based on aforementioned criteria and future method development using LC-MS/MS will benefit from the application of this systematic review.

New LC-MS/MS method with single-step pretreatment analyzes fat-soluble vitamins in plasma and amniotic fluid

Fat-soluble vitamins (FSVs), A, D, and E, are components of prenatal vitamin care. Previously, limited evidence existed to explain on a molecular level how maternal FSV supplementation affects the fetus during pregnancy. We developed a simplified LC-MS/MS method to simultaneously detect FSVs in maternal plasma (MP) and amniotic fluid (AF); we used this approach to investigate the correlation between FSV levels in these two matrices. With this method, we circumvented frequently used liquid-liquid extraction or solid-phase extraction methods and, instead, used simple protein precipitation with acetonitrile for sample preparation. This method displayed satisfactory linearity, intra- and inter-day imprecision, and accuracy. We validated the consistency with standard reference material 972a and 968f certification. In analysis of MP and AF samples from 50 pregnant women in the second trimester, concentrations of retinol, 25-hydroxyvitamin D3 [25(OH)D3], and α-tocopherol (reflecting vitamins A, D, and E, respectively) were lower in AF than in MP. Significant positive correlations existed between MP and AF for 25(OH)D3 (r = 0.667; P < 0.001) and retinol (r = 0.393; P = 0.005), but not for α-tocopherol (r = 0.145, P > 0.05). This novel LC-MS/MS method shows prominent applicability for FSV detection and the observed correlations contribute to research on fetal development.

Simultaneous determination of 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3 in human serum by ultra performance liquid chromatography: An economical and validated method with bovine serum albumin

A simple and economical method has been developed for simultaneous determination of human serum 25-hydroxyvitamin D₂ (25OHD₂) and 25-hydroxyvitamin D₃ (25OHD₃) using Ultra Performance Liquid Chromatography (UPLC). Non-human matrix of 4% BSA was used to construct the calibration curve and in quality control samples' preparation to avoid interference of the endogenous 25-hydroxyvitamin D (25OHD) present in the human serum. 25OHD₂, 25OHD₃ and dodecanophenone (internal standard, IS) were separated on a CORTECS solid-core particle column and monitored by photodiode array detector at wavelength of 265 nm within five min run time. The relationship between 25OHD concentration and peak area ratio (25OHD:IS) was linear over the range of 12.5 - 200 nM with mean correlation coefficients (r²) >0.998. The limit of detection (LOD) for 25OHD₂ and 25OHD₃ was 3.00 nM and 3.79 nM, while the lower limit of quantification (LLOQ) was 9.11 nM and 11.48 nM, respectively. High repeatability was obtained for both isomers with intra-day CV% <5.6% and <5.3% for inter-day assay. This method was further tested with a commercial lyophilized serum control with an accuracy of 92.87-108.31% and applied on 214 human serum samples. In summary, this validated method with BSA can be reliably applied for routine quantification of 25OHD in adults.

Analysis of retinol, α-tocopherol, 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3 in plasma of patients with cardiovascular disease by HPLC-MS/MS method

Fat-soluble vitamins play a pivotal role in the progression of atherosclerosis and the development of cardiovascular disease. Therefore, plasma monitoring of their concentrations may be useful in the diagnosis of these disorders as well as in the process of treatment. The study aimed to develop and validate an HPLC-MS/MS method for determination of retinol, α-tocopherol, 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3 in plasma of patients with cardiovascular disease. The analytes were separated on an HPLC Kinetex F5 column via gradient elution with water and methanol, both containing 0.1% (v/v) formic acid. Detection of the analytes was performed on a triple-quadrupole MS with multiple reaction monitoring via electrospray ionization. The analytes were isolated from plasma samples with liquid-liquid extraction using hexane. Linearity of the analyte calibration curves was confirmed in the ranges 0.02-2 μg/mL for retinol, 0.5-20 μg/mL for α-tocopherol, 5-100 ng/mL for 25-hydroxyvitamin D2 and 2-100 ng/mL for 25-hydroxyvitamin D3. Intra- and inter-assay precision and accuracy of the method were satisfactory. Short- and long-term stabilities of the analytes were determined. The HPLC-MS/MS method was applied for the determination of the above fat-soluble vitamin concentrations in patient plasma as potential markers of the cardiovascular disease progression.

A simultaneous quantitative method for vitamins A, D and E in human serum using liquid chromatography-tandem mass spectrometry

Non-classical roles of fat-soluble vitamins (FSVs) in many pathologies including cancer have been identified. There is also evidence of hormonal interactions between two of these vitamins, A and D. As a result of this enhanced clinical association with disease, translational clinical research and laboratory requests for FSV measurement has significantly increased. However there are still gaps in the analytical methods available for the measurement of these vitamins. This study aimed to develop a method for simultaneous quantification of 25-hydroxyvitamin-D2 (25-OHD2), 25-hydroxyvitamin-D3 (25-OHD3) and its 3-epimer (epi-25-OHD3), retinol and α-tocopherol in human serum using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The procedure was developed and validated across two LC-MS/MS platforms, using commercial calibrators referenced to certified reference materials, controls, and deuterated internal standards. The samples were prepared by liquid-liquid extraction prior to injection and LC separation (using a Pursuit-PFP column) on two Agilent MS/MS systems (6410 and 6490) in electrospray ionisation positive mode with multiple reaction monitoring. Identification and quantification of 25-OHD3 from its 3-epimer as well as 25-OHD2, retinol and α-tocopherol were achieved. The dynamic ranges were 4-160 nmol/L for 25-OHD2 and epi-25-OHD3, 4-200 nmol/L for 25-OHD3, 0.1-4.0μmol/L for retinol and 4-70μmol/L for α-tocopherol with correlation (r(2)) of 0.997-0.998. Based on participation in an external quality assurance program, the overall performance of the simultaneous methods were: imprecision (CV%) and inaccuracy (average bias) 3.0% and 3.2 nmol/L, respectively, for 25-OHD3; 5.0% and 0.04μmol/L, respectively, for retinol; and 4.7% and 0.2μmol/L, respectively, for α-tocopherol. In summary, two simple LC-MS/MS methods were successfully developed and validated for the simultaneous quantification of the three vitamin D metabolites (25-OHD2, 25-OHD3 and 3-epimer of 25-OHD3), vitamin A (retinol) and vitamin E (α-tocopherol) in serum.