Vitamin K Status Based on K1, MK-4, MK-7, and Undercarboxylated Prothrombin Levels in Adolescent and Adult Patients with Cystic Fibrosis: A Cross-Sectional Study.

The available evidence on vitamin K status in cystic fibrosis (CF) is scarce, lacking data on vitamin K2 (menaquinones-MK). Therefore, we assessed vitamin K1, MK-4 and MK-7 concentrations (LC-MS/MS) in 63 pancreatic insufficient and modulator naïve CF patients, and compared to 61 healthy subjects (HS). Vitamin K1 levels did not differ between studied groups. MK-4 concentrations were higher (median <1st-3rd quartile>: 0.778 <0.589-1.086> vs. 0.349 <0.256-0.469>, p < 0.0001) and MK-7 levels lower (0.150 <0.094-0.259> vs. 0.231 <0.191-0.315>, p = 0.0007) in CF patients than in HS. MK-7 concentrations were higher in CF patients receiving K1 and MK-7 supplementation than in those receiving vitamin K1 alone or no supplementation. Moreover, vitamin K1 concentrations depended on the supplementation regime. Based on multivariate logistic regression analysis, we have found that MK-7 supplementation dose has been the only predictive factor for MK-7 levels. In conclusion, vitamin K1 levels in CF are low if not currently supplemented. MK-4 concentrations in CF patients supplemented with large doses of vitamin K1 are higher than in HS. MK-7 levels in CF subjects not receiving MK-7 supplementation, with no regard to vitamin K1 supplementation, are low. There do not seem to be any good clinical predictive factors for vitamin K status.

The Effect of Circulating Zinc, Selenium, Copper and Vitamin K1 on COVID-19 Outcomes: A Mendelian Randomization Study.

Background & Aims: Previous results from observational, interventional studies and in vitro experiments suggest that certain micronutrients possess anti-viral and immunomodulatory activities. In particular, it has been hypothesized that zinc, selenium, copper and vitamin K1 have strong potential for prophylaxis and treatment of COVID-19. We aimed to test whether genetically predicted Zn, Se, Cu or vitamin K1 levels have a causal effect on COVID-19 related outcomes, including risk of infection, hospitalization and critical illness. Methods: We employed a two-sample Mendelian Randomization (MR) analysis. Our genetic variants derived from European-ancestry GWAS reflected circulating levels of Zn, Cu, Se in red blood cells as well as Se and vitamin K1 in serum/plasma. For the COVID-19 outcome GWAS, we used infection, hospitalization or critical illness. Our inverse-variance weighted (IVW) MR analysis was complemented by sensitivity analyses including a more liberal selection of variants at a genome-wide sub-significant threshold, MR-Egger and weighted median/mode tests. Results: Circulating micronutrient levels show limited evidence of association with COVID-19 infection, with the odds ratio [OR] ranging from 0.97 (95% CI: 0.87-1.08, p-value = 0.55) for zinc to 1.07 (95% CI: 1.00-1.14, p-value = 0.06)-i.e., no beneficial effect for copper was observed per 1 SD increase in exposure. Similarly minimal evidence was obtained for the hospitalization and critical illness outcomes with OR from 0.98 (95% CI: 0.87-1.09, p-value = 0.66) for vitamin K1 to 1.07 (95% CI: 0.88-1.29, p-value = 0.49) for copper, and from 0.93 (95% CI: 0.72-1.19, p-value = 0.55) for vitamin K1 to 1.21 (95% CI: 0.79-1.86, p-value = 0.39) for zinc, respectively. Conclusions: This study does not provide evidence that supplementation with zinc, selenium, copper or vitamin K1 can prevent SARS-CoV-2 infection, critical illness or hospitalization for COVID-19.

Vitamin K and Kidney Transplantation.

The assessment of the vitamin K status and its effects on clinical outcomes in kidney transplantation (KT) patients has sparked interest, but it is still largely unfulfilled. In part, this is due to difficulties in laboratory measurements of vitamin K, especially K2 vitamers. Vitamin K status is currently best assessed by measuring undercarboxylated vitamin-K-dependent proteins. The relative contribution of vitamin K1 and K2 to the health status of the general population and CKD (chronic kidney disease) patients, including KT patients, is also poorly studied. Through a complete and first review of the existing literature, we summarize the current knowledge of vitamin K pathophysiology and its potential role in preventing KT complications and improving organ survival. A specific focus is placed on cardiovascular complications, bone fractures, and the relationship between vitamin K and cancer. Vitamin K deficiency could determine adverse outcomes, and KT patients should be better studied for vitamin K assessment and modalities of effective therapeutic approaches.

Nutritional Therapy with Vitamin K1 Is Effective in the Improvement of Vitamin K Status and Bone Turnover Markers in Patients with Severe Motor and Intellectual Disabilities.

We have previously reported that patients with severe motor and intellectual disabilities (SMID) have a high prevalence of vitamin K deficiency both in the liver and bone. Thus, vitamin K therapy for SMID patients should be considered. In the present study, we have studied the efficacy of nutritional therapy with vitamin K1 for improving their vitamin K status and bone metabolism markers in patients with SMID. During the 3-mo period, 19 patients under enteral feeding received vitamin K1 treatment, the dose of which was determined to meet each subject's energy requirement. Biomarkers of vitamin K insufficiency; protein induced by vitamin K absence or antagonist-II (PIVKA-II), undercarboxylated osteocalcin (ucOC), intact osteocalcin (intact OC) and bone turnover markers (tartrate-resistant acid phosphatase-5b: TRACP-5b and bone alkaline phosphatase: BAP) were measured at baseline and post treatment. The ucOC/OC ratio was calculated as a more sensitive index than ucOC for vitamin K status in the bone. After treatment, the median vitamin K intake increased from 66 to 183 µg/d, and serum levels of PIVKA-II and ucOC/OC ratio were significantly decreased. Decrements of serum ucOC level and ucOC/OC ratio were significantly associated with vitamin K intake, indicating that both markers well reflect the dose-dependent vitamin K effects. Serum levels of BAP and TRACP-5b were significantly increased after vitamin K1 therapy. Nutritional therapy with vitamin K1 effectively improved the markers for vitamin K status and bone turnover, and was considered to be a good candidate for treatment in SMID patients.

In Search of Normality for Vitamin K1: Establishing Age-Dependent Reference Intervals in the Danish Population.

BACKGROUND: A growing body of evidence suggests that vitamin K has beneficial effects on human health, especially cardiovascular and bone health. Vitamin K1 (phylloquinone), the predominant form of vitamin K in blood, is regarded as an indicator of vitamin K status, but to our knowledge no reference intervals (RIs) have been established for vitamin K1. METHODS: In this population-based study, vitamin K1 was measured in serum from 3808 Caucasian individuals without diabetes from 26 to 78 years of age. The need for gender- and age-partitioned vitamin K1 reference intervals was evaluated using Lahti's method, and exclusion criteria were defined to obtain as healthy a study group as possible. The excluded subgroups were tested for differences in mean serum vitamin K1 levels. Serum vitamin K1 levels were quantified using an in-house newly developed, validated, and highly sensitive online SPE-LC-MS/MS method with a limit of quantitation of (LOQ) 0.05 nmol/L. RESULTS: The reference interval for serum vitamin K1 was 0.22 to 3.95 nmol/L for individuals aged 26 to 44 years and 0.35 to 3.70 nmol/L for individuals aged 45 to 78. Similar age-specific reference intervals were established for vitamin K1-triglyceride ratio being 0.20 to 3.16 and 0.31 to 3.44, respectively. No significant difference was found between genders. Serum vitamin K1 was detectable in all serum samples. Individuals with known comorbidity were found to have significantly lower serum vitamin K1 compared to those without comorbidity. Current smokers had lower serum vitamin K1 compared to nonsmokers. CONCLUSION: Age-dependent reference intervals were established for serum vitamin K1 and vitamin K1-triglyceride ratio in a well-defined, healthy Caucasian population. Lower serum vitamin K1 levels were found in individuals with known comorbidity, suggesting an association between serum vitamin K1 and disease status. Further studies are needed to determine an optimal serum vitamin K1 level.

Vitamin K status, cardiovascular disease, and all-cause mortality: a participant-level meta-analysis of 3 US cohorts.

BACKGROUND: Vitamin K-dependent proteins in vascular tissue affect vascular stiffness and calcification, which is associated with cardiovascular disease (CVD) and all-cause mortality. OBJECTIVE: To determine the association of circulating vitamin K concentrations with CVD and all-cause mortality by conducting a participant-level meta-analysis. METHODS: We obtained individual participant-level data from the Health, Aging, and Body Composition Study, the Multi-Ethnic Study of Atherosclerosis, and the Framingham Offspring Study, known cohorts with available measures of fasting circulating phylloquinone (vitamin K-1) and confirmed CVD events and mortality. Circulating phylloquinone was measured in a central laboratory from fasting blood samples and categorized as ≤0.5 nmol/L, >0.5-1.0 nmol/L, and >1.0 nmol/L. Multivariable Cox proportional hazard regression with multiple imputations was used to evaluate the association of circulating phylloquinone with incident CVD and all-cause mortality risk. RESULTS: Among 3891 participants (mean age 65 ± 11 y; 55% women; 35% nonwhite), there were 858 incident CVD events and 1209 deaths over a median of 13.0 y. The risk of CVD did not significantly differ according to circulating phylloquinone [fully adjusted HR (95% CI) relative to >1.0 nmol/L: ≤0.5 nmol/L, 1.12 (0.94, 1.33); >0.5-1.0 nmol/L, 1.02 (0.86, 1.20)]. Participants with ≤0.5 nmol/L circulating phylloquinone had an adjusted 19% higher risk of all-cause mortality compared with those with >1.0 nmol/L [fully adjusted HR (95% CI): 1.19 (1.03, 1.38)]. Mortality risk was similar in participants with >0.5-1.0 nmol/L compared with >1.0 nmol/L [fully adjusted HR (95% CI): 1.04 (0.92, 1.17)]. CONCLUSIONS: Low circulating phylloquinone concentrations were associated with an increased risk of all-cause mortality, but not of CVD. Additional studies are needed to clarify the mechanism underlying this association and evaluate the impact of increased phylloquinone intake on cardiovascular and other health outcomes in individuals with low vitamin K status.

Reversed phase UPLC/APCI-MS determination of Vitamin K1 and menaquinone-4 in human plasma: Application to a clinical study.

A rapid and sensitive liquid chromatographic-tandem mass spectrometric method was developed and validated to simultaneously quantitate vitamin K1 (PK) and vitamin K2 (MK-4) concentrations in human plasma to evaluate nutritional interventions. Charcoal-stripped human plasma was used for standard and calibration preparation with vitamin E-d6 as the internal standard. Patient plasma samples were extracted using n-hexane and analytes separated using an ACE -PFP C18 column (50 × 2.1 mm, 3 µ) equipped with standard C18 guard. The mobile phase consisted of 0.1 % formic acid in water and 0.1 % formic acid in methanol at a flow rate of 0.5 mL/min. Analyte quantification was achieved by using MS/MS with a positive atmospheric pressure chemical ionization in multiple reaction monitoring (MRM) mode. The lower limit of quantification was 0.01 ng/mL for both PK and MK-4. The assay was linear over the concentration range from 0.01-50 ng/mL for all analytes with a determination coefficient (r2) of 0.998 or better. The intra-and inter-day accuracy and precision were within the acceptable limits per FDA guidance. The validated method was successfully applied to a clinical study for quantification of PK and MK-4 in human plasma to assess nutritional status and dietary interventions in patients with neurodegenerative diseases. Baseline plasma concentrations of PK and MK-4 ranged from 0.23 to 1.81 ng/mL and 0.33-0.57 ng/mL, respectively.

Concentrations of Circulating Phylloquinone, but Not Cerebral Menaquinone-4, Are Positively Correlated with a Wide Range of Cognitive Measures: Exploratory Findings in Centenarians.

BACKGROUND: Vitamin K (VK) exists in the form of phylloquinone (PK) and menaquinones (MKs). Roles of VK on cognitive health in the elderly are emerging, but there is limited evidence on VK uptake and metabolism in human brain. OBJECTIVES: The primary objective of this study was to characterize VK distribution in brains of an elderly population with varied cognitive function. In addition, associations among circulating (a biomarker of VK intake) and cerebral VK concentrations and cognition were investigated. METHODS: Serum or plasma (n = 27) and brain samples from the frontal cortex (FC; n = 46) and the temporal cortex (TC; n = 33) were acquired from 48 decedents (aged 98-107 y; 25 demented and 23 nondemented) enrolled in the Georgia Centenarian Study. Both circulating and brain VK concentrations were measured using HPLC with fluorescence detection. Cognitive assessment was performed within 1 y prior to mortality. Partial correlations between serum/plasma or cerebral VK concentrations and cognitive function were performed, adjusting for covariates and separating by dementia and antithrombotic use. RESULTS: MK-4 was the predominant vitamer in both FC (mean ± SD = 4.92 ± 2.31 pmol/g, ≥89.15% ± 5.09% of total VK) and TC (4.60 ± 2.11 pmol/g, ≥89.71% ± 4.43% of total VK) regardless of cognitive status. Antithrombotic users had 34.0% and 53.9% lower MK-4 concentrations in FC (P < 0.05) and TC (P < 0.001), respectively. Circulating PK was not correlated with cerebral MK-4 or total VK concentrations. Circulating PK concentrations were significantly associated with a wide range of cognitive measures in nondemented centenarians (P < 0.05). In contrast, cerebral MK-4 concentrations were not associated with cognitive performance, either before or after exclusion of antithrombotic users. CONCLUSIONS: Circulating VK concentrations are not related to cerebral MK-4 concentrations in centenarians. Cerebral MK-4 concentrations are tightly regulated over a range of VK intakes and cognitive function. Circulating PK may reflect intake of VK-rich foods containing other dietary components beneficial to cognitive health. Further investigation of VK uptake and metabolism in the brain is warranted.

Vitamin K Status and Mobility Limitation and Disability in Older Adults: The Health, Aging, and Body Composition Study.

BACKGROUND: Vitamin K has been implicated in chronic diseases associated with increased risk for mobility disability, such as osteoarthritis and cardiovascular disease. However, the association between vitamin K status and mobility disability is unknown. Therefore, we examined the association between vitamin K status and incident mobility disability in the Health, Aging, and Body Composition Study. METHODS: Plasma phylloquinone (vitamin K1) was categorized as <0.5, 0.5-<1.0 and ≥1.0 nmol/L (n = 1,323, 48% male). Plasma ucMGP, which increases when vitamin K status is low, was measured in 716 participants and categorized into tertiles. Mobility limitation and disability, defined as two consecutive semiannual reports of having any or a lot of difficulty walking a one-fourth mile or climbing 10 steps without resting, were assessed over a median 6-10 years of follow-up. Multivariate Cox proportional hazard models were used to evaluate the association between vitamin K status and incident mobility limitation and disability. RESULTS: Participants with plasma phylloquinone less than 0.5 nmol/L were more likely to develop mobility limitation and disability compared to those with at least 1.0 nmol/L (adjusted HR (95% CI) mobility limitation: 1.27 (1.05-1.53); disability: 1.34 (1.01-1.76)). After further adjustment for knee pain, the associations were partially attenuated (HR (95% CI) mobility limitation: 1.20 (0.99-1.45); disability: 1.26 (0.96-1.67)). Plasma ucMGP was not associated with incident mobility limitation, but was nonlinearly associated with incident mobility disability (HR (95% CI), compared to tertile 1: tertile 2 = 1.64 (1.19-2.27), tertile 3 = 1.17 (0.83-1.66), fully adjusted). CONCLUSION: Our results suggest vitamin K may be involved in the disablement process in older age. Future studies are needed to confirm our findings and clarify the underlying mechanism.

Circulating phylloquinone, inactive Matrix Gla protein and coronary heart disease risk: A two-sample Mendelian Randomization study.

BACKGROUND AND AIMS: Multiple observational studies and small-scale intervention studies suggest that high vitamin K intake is associated with improved markers for cardiovascular health. Circulating phylloquinone solely represents phylloquinone (vitamin K1) intake, while dephosphorylated uncarboxylated Matrix Gla Protein (dp-ucMGP) represents both phylloquinone and menaquinone (vitamin K2) intake. This study aims to investigate the causal relationship between genetically predicted vitamin K concentrations and the risk of CHD via a two-sample Mendelian Randomization approach. DESIGN: We used data from three studies: the European Prospective Investigation into Cancer and Nutrition (EPIC)-CVD case-cohort study, CARDIOGRAMplusC4D and the UK Biobank, resulting in 103,097 CHD cases. Genetically predicted vitamin K concentrations were measured using SNPs related to circulating phylloquinone and dp-ucMGP. We calculated a genetic risk score (GRS) including four SNPs (rs2108622, rs2192574, rs4645543 and rs6862071) related to circulating phylloquinone levels from a genome wide association study. Rs4236 was used as an instrumental variable for dp-ucMGP. Inverse-variance weighted (IVW) analysis was used to obtain Risk Ratios (RRs) for the causal relationship between phylloquinone and dp-ucMGP concentrations and CHD risk. RESULTS: Using the genetic score for circulating phylloquinone, we found that circulating phylloquinone was not causally related to CHD risk (RR 1.00 (95%-CI: 0.98; 1.04)). Lower genetically predicted dp-ucMGP concentration was associated with a lower CHD risk with a RR of 0.96 (95%-CI: 0.93; 0.99) for every 10 µg/L decrease in dp-ucMGP. CONCLUSIONS: This study did not confirm a causal relationship between circulating phylloquinone and lower CHD risk. However, lower dp-ucMGP levels may be causally related with a decreased CHD risk. This inconsistent result may reflect the influence of menaquinones in the association with CHD.

Vitamin K status and inflammation are associated with cognition in older Irish adults.

Studies have shown associations between reduced vitamin K status and poor cognitive function. However, despite this apparent link, direct studies measuring cognitive function, vitamin K status and inflammation are lacking. In the current study, The ELDERMET cohort was investigated to identify associations between cognition, vitamin K status and inflammation. The primary aim of the ELDERMET study was to investigate the relationship between gut bacteria, diet, lifestyle and health in 500 older Irish adults. Significant differences in serum phylloquinone, dietary phylloquinone and inflammatory markers were found across varying levels of cognitive function, after controlling for sex, age, body mass index (BMI), triglycerides and blood pressure. In addition, significantly higher levels of dietary phylloquinone were found in those with better cognition compared to those with the poorest function. Higher levels of inflammatory were also associated with poor cognition. Furthermore, both dietary and serum phylloquinone were significant independent predictors of good cognitive function, after controlling for confounders. This study highlights the importance of dietary vitamin K as a potentially protective cognitive factor; it also provides evidence for the correlation between cognition and inflammation. Strategies should be devised by which elderly populations can access rich dietary sources of phylloquinone to maintain cognition.

Laboratory assessment of vitamin K status.

Vitamin K is required for the É£-carboxylation of specific glutamic acid residues within the Gla domain of the 17 vitamin K-dependent proteins (VKDPs). The timely detection and correction of vitamin K deficiency can protect against bleeding. Vitamin K also plays a role in bone metabolism and vascular calcification. Patients at increased risk of vitamin K deficiency include those with a restricted diet or malnutrition, lipid malabsorption, cancer, renal disease, neonates and the elderly. Coagulation assays such as the prothrombin time have been used erroneously as indicators of vitamin K status, lacking sufficient sensitivity and specificity for this application. The measurement of phylloquinone (K1) in serum is the most commonly used marker of vitamin K status and reflects abundance of the vitamin. Concentrations <0.15 µg/L are indicative of deficiency. Disadvantages of this approach include exclusion of the other vitamin K homologues and interference from recent dietary intake. The cellular utilisation of vitamin K is determined through measurement of the prevalence of undercarboxylated VKDPs. Most commonly, undercarboxylated prothrombin (Protein Induced by Vitamin K Absence/antagonism, PIVKA-II) is used (reference range 17.4-50.9 mAU/mL (Abbott Architect), providing a retrospective indicator of hepatic vitamin K status. Current clinical applications of PIVKA-II include supporting the diagnosis of vitamin K deficiency bleeding of the newborn, monitoring exposure to vitamin K antagonists, and when used in combination with α-fetoprotein, as a diagnostic marker of hepatocellular carcinoma. Using K1 and PIVKA-II in tandem is an approach that can be used successfully for many patient cohorts, providing insight into both abundance and utilisation of the vitamin.

The Contribution of Lipids to the Interindividual Response of Vitamin K Biomarkers to Vitamin K Supplementation.

SCOPE: A better understanding of factors contributing to interindividual variability in biomarkers of vitamin K can enhance the understanding of the equivocal role of vitamin K in cardiovascular disease. Based on the known biology of phylloquinone, the major form of vitamin K, it is hypothesized that plasma lipids contribute to the variable response of biomarkers of vitamin K metabolism to phylloquinone supplementation. METHODS AND RESULTS: The association of plasma lipids and 27 lipid-related genetic variants with the response of biomarkers of vitamin K metabolism is examined in a secondary analysis of data from a 3-year phylloquinone supplementation trial in men (n = 66) and women (n = 85). Year 3 plasma triglycerides (TG), but not total cholesterol, LDL-cholesterol, or HDL-cholesterol, are associated with the plasma phylloquinone response (men: ß = 1.01, p < 0.001, R2  = 0.34; women: ß = 0.61, p = 0.008, R2  = 0.11; sex interaction p = 0.077). Four variants and the TG-weighted genetic risk score are associated with the plasma phylloquinone response in men only. Plasma lipids are not associated with changes in biomarkers of vitamin K function (undercarboxylated osteocalcin and matrix gla protein) in either sex. CONCLUSION: Plasma TG are an important determinant of the interindividual response of plasma phylloquinone to phylloquinone supplementation, but changes in biomarkers of vitamin K carboxylation are not influenced by lipids.

A Multi-institutional Study on the Mid-Term Outcomes of Single Anastomosis Duodeno-Ileal Bypass as a Surgical Revision Option After Sleeve Gastrectomy.

INTRODUCTION: Recently, a single anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S) has become increasingly popular for patients with BMI > 50 as a primary or staged surgery. Staging allows surgeons to do the sleeve gastrectomy (SG) first with the conversion only happening when a failure or technical challenge is identified. PURPOSE: We present the mid-term outcomes of SADI bypass surgery after SG. METHOD: A retrospective analysis was performed on a prospective database from four institutions. Ninety-six patients were identified from 2013 to 2018. Patients were divided into two groups: one had two-stage SADI because of insufficient weight loss, the second had planned two-stage SADI because of super obesity (BMI > 50 kg/m2). Incidence of complications was divided into < 30 days and > 30 days. RESULT: Of 96 patients, 3 patients were completely lost to follow-up. The mean age was 44.8 ± 11.3 years. There were no deaths or conversion to open surgery. The postoperative early complication and late complication rate was 5.3% and 6.4% respectively. At 24 months, group 2 had higher %weight loss (WL) and change in BMI units compared to group 1 with statistically significant difference. The average WL and change in BMI for entire patient's population at 24 months after 2nd stage SADI was 20.5% and 9.4 units respectively. The remission rate for DM was 93.7% with or without the use of medication. CONCLUSION: The two-stage approach to SADI-S appears technically simpler than a single compromised operation. However, this approach needs more patients to understand its limitations.

Effects of Ketoconazole, a CYP4F2 Inhibitor, and CYP4F2*3 Genetic Polymorphism on Pharmacokinetics of Vitamin K1.

The objective of this study was to evaluate whether cytochrome P450 (CYP)4F2 is involved in the exposure of vitamin K1 through a drug interaction study with ketoconazole, a CYP4F2 inhibitor, and a pharmacogenetic study with CYP4F2*3. Twenty-one participants with different CYP4F2*3 polymorphisms were enrolled (8 for *1/*1, 7 for *1/*3, and 6 for *3/*3). All participants were treated twice daily for 5 days with 200 mg of ketoconazole or placebo. Finally, a single dose of 10 mg vitamin K1 was administered, plasma levels of vitamin K1 were measured, and its pharmacokinetics was assessed. Ketoconazole elevated the plasma levels of vitamin K1 and increased the average area under the concentration-time curve (AUCinf ) and peak concentration by 41% and 40%, respectively. CYP4F2*3 polymorphism also affected plasma levels of vitamin K1 and its pharmacokinetics in a gene dose-dependent manner. The average AUCinf value was 659.8 ng·h/mL for CYP4F2*1/*1, 878.1 ng·h/mL for CYP4F2*1/*3, and 1125.2 ng·h/mL for CYP4F2*3/*3 (P = .010). This study revealed that ketoconazole and CYP4F2*3 polymorphism substantially increased the exposure of vitamin K1 in humans. These findings provide a plausible explanation for variations in warfarin dose requirements resulting from interindividual variations in vitamin K1 exposure due to CYP4F2-related drug interactions and genetic polymorphisms.

Quantitation of vitamin K1 in serum using online SPE-LC-MS/MS and the challenges of working with vitamin K.

Vitamin K1 (phylloquinone) is one of the vitamin Ks. Several studies have previously investigated the role of vitamin K1 status in respect to disease, but without consistent results. Since vitamin K deficiency has been associated with different disease states it is important to develop a biochemical analysis with sufficient sensitivity and a low limit of quantitation (LOQ). The vitamin Ks are very fat-soluble. This non-polar nature has given rise to several challenges during the method development, because vitamin K1 sticks to materials used during the process and is lost during evaporation. We found that reducing the sample preparation as much as possible offline, instead using online SPE-LC-MS/MS improves recovery and gives satisfactory chromatograms. An Protein BEH C4 column, 300 Š(50 × 2.1 mm, 1.7 µm particle size) was used as trap column and a Phenyl-Hexyl-LC-column, 100 Š(100 × 2.1 mm, 2.6 µm particle size) was used as analytical column. The mobile phases consisted of 30 µmol/L NH4F in water and 30 µmol/L NH4F in MeOH. A triple quadrupole tandem mass spectrometer with atmospheric pressure chemical ionization (APCI) ion source, positive ion mode, was used to perform the mass spectrometric measurements. The method is simple, highly sensitive and fast. The method was validated for vitamin K1 with good analytical performance. With a LOQ of 0.05 nmol/L it is to our knowledge the vitamin K1 method with lowest LOQ reported to date in the literature. It can easily be automated and applied in a routine diagnostic laboratory. Blood collection tubes with different additives were tested and showed no difference. Stability of vitamin K1 in serum was tested at different temperatures (-20 °C, 4 °C and in light and dark at 20 °C over a period of 30 days) and showed that vitamin K1 is light sensitive in serum even after only one day.

Effects of nutritional intervention upon bone turnover in elderly hip fracture patients. Randomized controlled trial.

BACKGROUND AND AIM: Hip fracture patients are at great risk of malnutrition, but documentation of the effect of nutrition supplementation in this group is sparse and inconclusive. The aim of this study was to examine if personalized nutrition advice combined with vitamin K1, Ca and vitamin D could improve bone turnover 4 months after hip fracture. DESIGN: This is a preplanned sub study of a randomized controlled trial of orthogeriatric care. The intervention group received orthogeriatric care, including nutrition advice and supplementation. The control group received usual care at the orthopedic ward. Blood was drawn for measurements of a number of vitamins and of bone turnover markers upon admission and at four months follow up. RESULTS: 71 patients (31 in the intervention group and 40 controls) had available data at 4 months as well as at baseline. After four months, vitamin K1 and 25(OH)D were higher in the intervention group compared with controls; vitamin K1: 1.0 ± 1.2 vs 0.6 ± 0.6 ng/ml, p = 0.09, 25(OH)D: 60 ± 29 vs 43 ± 22 nmol/L, p = 0.01 when adjusted for baseline differences. In a secondary, unadjusted analysis, comprising all patients with available four months data (n = 136), the differences were statistically significant for vitamin K1 as well as 25(OH)D (p = 0.03 and p < 0.001, respectively). There was a non-significant increase in 25(OH)D in the intervention group from baseline to 4 months follow up, and a significant decrease in the control group. There was no difference in bone turnover markers between the two groups at 4 months follow up. A substantial loss of weight and physical function was found in both groups. CONCLUSIONS: The supplementation of 25(OH)D and vitamin K1 improved serum concentrations of these vitamins, but this did not translate into any improvement in the bone turnover markers. The RCT is registered in ClinicalTrials.govNCT01009268 and NCT01738776.

Circulating Phylloquinone Concentrations and Risk of Type 2 Diabetes: A Mendelian Randomization Study.

This study investigated the causal relation between circulating phylloquinone (vitamin K1) concentrations and type 2 diabetes by using a Mendelian randomization (MR) approach. We used data from three studies: the European Prospective Investigation into Cancer and Nutrition (EPIC)-InterAct case-cohort study, Diabetes Genetics Replication and Meta-analysis (DIAGRAM), and the UK Biobank, resulting in 69,647 subjects with type 2 diabetes. We calculated a weighted genetic risk score including four genetic variants previously found to be associated with circulating phylloquinone concentrations. Inverse-variance weighted analysis was used to obtain a risk ratio (RR) for the causal relation between circulating phylloquinone concentrations and risk of type 2 diabetes. Presence of pleiotropy and the robustness of the results were assessed using MR-Egger and weighted-median analyses. Genetically predicted concentrations of circulating phylloquinone were associated with lower risk of type 2 diabetes with an RR of 0.93 (95% CI 0.89; 0.97) per every natural logarithm (Ln)-nmol/L-unit increase in circulating phylloquinone. The MR-Egger and weighted median analyses showed RRs of 0.94 (0.86; 1.02) and 0.93 (0.88; 0.98), respectively, indicating no pleiotropy. In conclusion, our study supports that higher circulating phylloquinone may be causally related with lower risk of type 2 diabetes, highlighting the importance of sufficient phylloquinone in the human diet.

Plasma Response to Deuterium-Labeled Vitamin K Intake Varies by TG Response, but Not Age or Vitamin K Status, in Older and Younger Adults.

Background: Phylloquinone is the primary form of vitamin K in the diet and circulation. Large intra- and interindividual variances in circulating phylloquinone have been partially attributed to age. However, little is known about the nondietary factors that influence phylloquinone absorption and metabolism. Similarly, it is not known if phylloquinone absorption is altered by the individual's existing vitamin K status. Objective: The purpose of this secondary substudy was to compare plasma response with deuterium-labeled phylloquinone intake in older and younger adults after dietary phylloquinone depletion and repletion. Methods: Forty-two older [mean ± SD age: 67.2 ± 8.0 y; body mass index (BMI; in kg/m2): 25.4 ± 4.6; n = 12 men, 9 women] and younger (mean ± SEM age: 31.8 ± 6.6 y; BMI: 25.5 ± 3.3; n = 9 men, 12 women) adults were maintained on sequential 28-d phylloquinone depletion (∼10 µg phylloquinone/d) and 28-d phylloquinone repletion (∼500 µg phylloquinone/d) diets. On the 23rd d of each diet phase, participants consumed deuterated phylloquinone-rich collard greens (2H-phylloquinone). Plasma and urinary outcome measures over 72 h were compared by age group, sex, and dietary phase via 2-factor repeated-measures ANOVA. Results: The plasma 2H-phylloquinone area under the curve (AUC) did not differ in response to phylloquinone depletion or repletion, but was 34% higher in older than in younger adults (P = 0.02). However, plasma 2H-phylloquinone AUC was highly correlated with the serum triglyceride (TG) AUC (r2 = 0.45). After adjustment for serum TG response, the age effect on the plasma 2H-phylloquinone AUC was no longer significant. Conclusions: Plasma 2H-phylloquinone response did not differ between phylloquinone depletion and repletion in older and younger adults. The age effect observed was explained by the serum TG response and was completely attenuated after adjustment. Plasma response to phylloquinone intake, therefore, seems to be a predominantly lipid-driven effect and not dependent on existing vitamin K status. More research is required to differentiate the effect of endogenous compared with exogenous lipids on phylloquinone absorption. This trial was registered at clinicaltrials.gov as NCT00336232.

Circulating Vitamin K1 Levels in Relation to Ischemic Stroke and Its Subtypes: A Mendelian Randomization Study.

Vitamin K plays a crucial role in blood coagulation, and hypercoagulability has been linked to atherosclerosis-related vascular disease. We used the Mendelian randomization study design to examine whether circulating vitamin K1 (phylloquinone) levels are associated with ischemic stroke. Four single-nucleotide polymorphisms associated with vitamin K1 levels were used as instrumental variables. Summary-level data for large artery atherosclerotic stroke (n = 4373 cases), small vessel stroke (n = 5386 cases), cardioembolic stroke (n = 7193 cases), and any ischemic stroke (n = 34,217 cases and 404,630 non-cases) were available from the MEGASTROKE consortium. Genetically-predicted circulating vitamin K1 levels were associated with large artery atherosclerotic stroke but not with any other subtypes or ischemic stroke as a whole. The odds ratios per genetically predicted one nmol/L increase in natural log-transformed vitamin K1 levels were 1.31 (95% confidence interval (CI) 1.12⁻1.53; p = 7.0 × 10-4) for large artery atherosclerotic stroke, 0.98 (95% CI 0.85⁻1.12; p = 0.73) for small vessel stroke, 1.01 (95% CI 0.90⁻1.14; p = 0.84) for cardioembolic stroke, and 1.05 (95% CI 0.99⁻1.11; p = 0.11) for any ischemic stroke. These findings indicate that genetic predisposition to higher circulating vitamin K1 levels is associated with an increased risk of large artery atherosclerotic stroke.