Tocopherol and phylloquinone biosynthesis in chloroplasts requires the phytol kinase VITAMIN E PATHWAY GENE5 (VTE5) and the farnesol kinase (FOLK).

Chlorophyll degradation causes the release of phytol, which is converted into phytyl diphosphate (phytyl-PP) by phytol kinase (VITAMIN E PATHWAY GENE5 [VTE5]) and phytyl phosphate (phytyl-P) kinase (VTE6). The kinase pathway is important for tocopherol synthesis, as the Arabidopsis (Arabidopsis thaliana) vte5 mutant contains reduced levels of tocopherol. Arabidopsis harbors one paralog of VTE5, farnesol kinase (FOLK) involved in farnesol phosphorylation. Here, we demonstrate that VTE5 and FOLK harbor kinase activities for phytol, geranylgeraniol, and farnesol with different specificities. While the tocopherol content of the folk mutant is unchanged, vte5-2 folk plants completely lack tocopherol. Tocopherol deficiency in vte5-2 plants can be complemented by overexpression of FOLK, indicating that FOLK is an authentic gene of tocopherol synthesis. The vte5-2 folk plants contain only ∼40% of wild-type amounts of phylloquinone, demonstrating that VTE5 and FOLK both contribute in part to phylloquinone synthesis. Tocotrienol and menaquinone-4 were produced in vte5-2 folk plants after supplementation with homogentisate or 1,4-dihydroxy-2-naphthoic acid, respectively, indicating that their synthesis is independent of the VTE5/FOLK pathway. These results show that phytyl moieties for tocopherol synthesis are completely but, for phylloquinone production, only partially derived from geranylgeranyl-chlorophyll and phytol phosphorylation by VTE5 and FOLK.

Dietary Vitamin K1 Intake and Incident Aortic Valve Stenosis.

BACKGROUND: Leaflet calcification contributes to the development and progression of aortic valve stenosis. Vitamin K activates inhibitors of vascular calcification and may modulate inflammation and skeletal bone loss. Therefore, we aimed to determine whether higher dietary intakes of vitamin K1 are associated with a lower incidence of aortic stenosis. METHODS: In the Danish Diet, Cancer and Health study, participants aged 50 to 64 years completed a 192-item food frequency questionnaire at baseline, from which habitual intakes of vitamin K1 were estimated. Participants were prospectively followed using linkage to nationwide registers to determine incident aortic valve stenosis (primary outcome) and aortic stenosis with subsequent complications (aortic valve replacement, heart failure, or cardiovascular disease-related mortality; secondary outcome). RESULTS: In 55 545 participants who were followed for a maximum of 21.5 years, 1085 were diagnosed with aortic stenosis and 615 were identified as having subsequent complications. Participants in the highest quintile of vitamin K1 intake had a 23% lower risk of aortic stenosis (hazard ratio, 0.77 [95% CI, 0.63-0.94]) and a 27% lower risk of aortic stenosis with subsequent complications (hazard ratio, 0.73 [95% CI, 0.56-0.95]), compared with participants in the lowest quintile after adjusting for demographics and cardiovascular risk factors. CONCLUSIONS: In this study, a high intake of vitamin K1-rich foods was associated with a lower incidence of aortic stenosis and a lower risk of aortic stenosis with subsequent complications.

Vitamin K converting enzyme UBIAD1 plays an important role in osteogenesis and chondrogenesis in mice.

Dietary vitamin K1 (phylloquinone: PK) and menaquinone (MK-n) are converted to menadione (MD) in the small intestine and then translocated to various tissues where they are converted to vitamin K2 (menaquinone-4: MK-4) by UbiA prenyltransferase domain containing protein 1 (UBIAD1). MK-4 is effective in bone formation and is used to treat osteoporosis in Japan. UBIAD1 is expressed in bone and osteoblasts and shows conversion to MK-4, but the role of UBIAD1 in osteogenesis is unknown. In this study, we investigated the function of UBIAD1 in osteogenesis using a tamoxifen-dependent UBIAD1-deficient mouse model. When UBIAD1 deficiency was induced from the first week of life, the femur was significantly shortened, and bone mineral density (BMD) was reduced. In addition, the expression of bone and chondrocyte matrix proteins and chondrocyte differentiation factors was significantly decreased. In primary cultured chondrocytes, chondrocyte differentiation was significantly reduced by UBIAD1 deficiency. These results suggest that UBIAD1 is an important factor for the regulation of chondrocyte proliferation and differentiation during osteogenesis.

Vitamin D and vitamin K1 as novel inhibitors of biofilm in Gram-negative bacteria.

BACKGROUND: The persistent surge in antimicrobial resistance represents a global disaster. The initial attachment and maturation of microbial biofilms are intimately related to antimicrobial resistance, which in turn exacerbates the challenge of eradicating bacterial infections. Consequently, there is a pressing need for novel therapies to be employed either independently or as adjuvants to diminish bacterial virulence and pathogenicity. In this context, we propose a novel approach focusing on vitamin D and vitamin K1 as potential antibiofilm agents that target Gram-negative bacteria which are hazardous to human health. RESULTS: Out of 130 Gram-negative bacterial isolates, 117 were confirmed to be A. baumannii (21 isolates, 17.9%), K. pneumoniae (40 isolates, 34.2%) and P. aeruginosa (56 isolates, 47.9%). The majority of the isolates were obtained from blood and wound specimens (27.4% each). Most of the isolates exhibited high resistance rates to ß-lactams (60.7-100%), ciprofloxacin (62.5-100%), amikacin (53.6-76.2%) and gentamicin (65-71.4%). Approximately 93.2% of the isolates were biofilm producers, with 6.8% categorized as weak, 42.7% as moderate, and 50.4% as strong biofilm producers. The minimum inhibitory concentrations (MICs) of vitamin D and vitamin K1 were 625-1250 µg mL-1 and 2500-5000 µg mL-1, respectively, against A. baumannii (A5, A20 and A21), K. pneumoniae (K25, K27 and K28), and P. aeruginosa (P8, P16, P24 and P27) clinical isolates and standard strains A. baumannii (ATCC 19606 and ATCC 17978), K. pneumoniae (ATCC 51503) and P. aeruginosa PAO1 and PAO14. Both vitamins significantly decreased bacterial attachment and significantly eradicated mature biofilms developed by the selected standard and clinical Gram-negative isolates. The anti-biofilm effects of both supplements were confirmed by a notable decrease in the relative expression of the biofilm-encoding genes cusD, bssS and pelA in A. baumannii A5, K. pneumoniae K28 and P. aeruginosa P16, respectively. CONCLUSION: This study highlights the anti-biofilm activity of vitamins D and K1 against the tested Gram-negative strains, which emphasizes the potential of these vitamins for use as adjuvant therapies to increase the efficacy of treatment for infections caused by multidrug-resistant (MDR) strains and biofilm-forming phenotypes. However, further validation through in vivo studies is needed to confirm these promising results.

Inverted region in the reaction of the quinone reduction in the A1-site of photosystem I from cyanobacteria.

Photosystem I from the menB strain of Synechocystis sp. PCC 6803 containing foreign quinones in the A1 sites was used for studying the primary steps of electron transfer by pump-probe femtosecond laser spectroscopy. The free energy gap (- ΔG) of electron transfer between the reduced primary acceptor A0 and the quinones bound in the A1 site varied from 0.12 eV for the low-potential 1,2-diamino-anthraquinone to 0.88 eV for the high-potential 2,3-dichloro-1,4-naphthoquinone, compared to 0.5 eV for the native phylloquinone. It was shown that the kinetics of charge separation between the special pair chlorophyll P700 and the primary acceptor A0 was not affected by quinone substitutions, whereas the rate of A0 → A1 electron transfer was sensitive to the redox-potential of quinones: the decrease of - ΔG by 400 meV compared to the native phylloquinone resulted in a ~ fivefold slowing of the reaction The presence of the asymmetric inverted region in the ΔG dependence of the reaction rate indicates that the electron transfer in photosystem I is controlled by nuclear tunneling and should be treated in terms of quantum electron-phonon interactions. A three-mode implementation of the multiphonon model, which includes modes around 240 cm-1 (large-scale protein vibrations), 930 cm-1 (out-of-plane bending of macrocycles and protein backbone vibrations), and 1600 cm-1 (double bonds vibrations) was applied to rationalize the observed dependence. The modes with a frequency of at least 1600 cm-1 make the predominant contribution to the reorganization energy, while the contribution of the "classical" low-frequency modes is only 4%.

Vitamin K insufficiency and the prophylaxis strategy in term healthy infants: A multicentre study.

BACKGROUND/AIM: Late vitamin K deficiency bleeding (VKDB) during early infancy is a serious problem worldwide. Vitamin K (VK) deficiency commonly occurs in newborns who are exclusively breastfed. Protein Induced by VK Absence (PIVKA-II) has been identified as an early indicator of subclinical VK deficiency in neonates, surpassing prothrombin time. To assess PIVKA-II levels at 48 h, 1 and 3 months of age in full-term newborns who were exclusively breastfed and received varying VKDB prophylaxis regimens. METHODS: A prospective observational study was conducted in four hospitals, enrolling 105 newborns. PIVKA-II levels were measured using a sandwich-type enzyme-linked immunosorbent assay. RESULTS: At 48 h of age, there was no significant difference in PIVKA-II concentrations between newborns who received intramuscular administration of 1 mg of phylloquinone (VK1) and those who received oral administration of 2 mg of VK1 at birth. At 1 and 3 months of life, infants who received any supplementation regimen between 2 and 14 weeks exhibited significantly lower PIVKA-II concentrations compared to infants who received only 1 mg of intramuscular VK1 at birth. The prophylaxis involving a dose of 1 mg of intramuscular VK1 at birth followed by oral administration of 150 µg/day of VK1 from the 2nd to the 14th week of life showed the lowest PIVKA-II blood concentrations. CONCLUSIONS: Oral supplementation of VK1 after discharge significantly reduced PIVKA-II concentrations in exclusively breastfed term infants. These findings suggest the importance of oral VK1 supplementation in exclusively breastfed infants during their first 3 months of life to avoid the risk of VK insufficiency.

A Negative Association between Plasma Phylloquinone and All-Cause Mortality in Chinese Adults with Hypertension: A Nested Case-Control Study.

BACKGROUND: Previous studies have revealed that vitamin K is essential for preventing various chronic diseases. Phylloquinone is the primary dietary and circulating form of vitamin K. However, data concerning the association between plasma phylloquinone and all-cause mortality are limited. OBJECTIVES: This study aimed to evaluate the association between plasma phylloquinone and risk of all-cause mortality and examine some potential confounders. METHODS: This study is a post hoc analysis of the RCT and a nested, case-control design was used. Enrolled participants had to have hypertension at baseline. Study initiation was 19 May, 2008, and the median follow-up was 4.5 y. A total of 604 mortality cases and 604 controls matched for age, sex, treatment group, and study site were included in this study. Odds ratios (OR) and 95% confidence intervals (CIs) of all-cause mortality were calculated using conditional or unconditional logistic regression, without or with adjusting for pertinent covariates, respectively. The concentration of phylloquinone was measured by liquid chromatography-tandem quadrupole mass spectrometry (LC-MS/MS). RESULTS: The mean and median phylloquinone levels were 1.62 nmol/L and 0.89 nmol/L, respectively. There was a significant negative association between log-transformed plasma phylloquinone and all-cause mortality after controlling for potential confounders (per 1 unit increase-OR: 0.79; 95% CI: 0.66, 0.95). Furthermore, the association of plasma phylloquinone with risk of all-cause mortality differed by body mass index (BMI) (<25 kg/m2 compared with ≥25 kg/m2, P-interaction = 0.004). A significant trend of decreasing risk with increasing concentration of phylloquinone was observed in participants with higher BMI (per 1 unit increase-OR: 0.71; 95% CI: 0.56, 0.90; P = 0.004). No significant correlation was found between phylloquinone and risk of all-cause mortality in those with BMI <25 kg/m2. CONCLUSIONS: In Chinese patients with hypertension, there was a significant negative association between baseline plasma phylloquinone and all-cause mortality, especially among those with higher BMI.

Observation of the neuroprotective efficacy of vitamin K in a streptozocin-induced diabetes model in chick embryos.

Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia due to insulin deficiency and/or resistance. Vitamin K (VK) is a group of fat-soluble molecules, including naturally occurring vitamin K1 (phylloquinone). vitamin K2 (menaquinone), and synthetic vitamin K3 (menadione). Beyond coagulation, the health benefits of VK have been described to play different roles in both physiological and pathological processes such as inflammation, energy metabolism, neuroprotection, cellular growth, and survival. It was aimed to observe the antioxidant and/or neuroprotective activity of vitamin K1 in our model of chick embryo diabetic neuropathy (DN) induced by streptozotocin (STZ). Ninety White Leghorn, fertile and 0-day-old SPF (specific pathogen-free) eggs (57 ± 4 gr) were used in the study. Chick embryo blood brain tissues were taken for biochemical evaluation. Plasma insulin and glucose levels were measured. In addition, brain tissue total antioxidant level (TAS), total oxidant level (TOS), malondialdehyde (MDA), and vascular endothelial growth factor (VEGF) levels were measured. Plasma glucose levels were higher in the STZ-treated groups and lower in the treatment groups. Plasma insulin levels were observed to be higher in STZ groups in groups treated with high VK. Low TAS, high MDA, TOS, and VEGF levels were recorded in brain tissue STZ groups. Low VEGF, TOS, and MDA levels were recorded in the group treated with the highest VK, while high TAS levels were observed. In our STZ-induced chick embryo diabetic neuropathy model, we observed that VK1 reduced oxidant damage by showing antioxidant properties or by modulating antioxidant enzymes.

Vitamin K1 intake is associated with lower risk for all-cause and cardiovascular disease mortality in community-dwelling older Australian women.

BACKGROUND AND AIMS: Assessing the relationship between vitamin K1 intakes, using region-specific food databases, with both all-cause, and cardiovascular disease (CVD) mortality warrants further investigation to inform future preventative strategies. Consequently, we examined the aforementioned associations in the Perth Longitudinal Study of Ageing Women (PLSAW). METHODS AND RESULTS: 1436 community-dwelling older Australian women (mean ± SD age 75.2 ± 2.7 years) completed a validated food frequency questionnaire at baseline (1998). Vitamin K1 intake was calculated based on an Australian vitamin K food database, supplemented with published data. All-cause and CVD mortality data was obtained from linked health records. Associations were examined using restricted cubic splines within Cox-proportional hazard models, adjusted for a range of cardiovascular and lifestyle related risk factors. Over 15 years of follow-up, 601 (41.9%) women died, with 236 deaths (16.4%) due to CVD. Compared to women with the lowest vitamin K1 intakes (Quartile 1, median 49.1 µg/day), those with the highest intakes (Quartile 4, median 119.3 µg/day) had lower relative hazards for all-cause mortality (HR 0.66 95%CI 0.51-0.86) and CVD mortality (HR 0.61 95%CI 0.41-0.92). A plateau in the inverse association was observed from vitamin K1 intakes of approximately ≥80 µg/day. CONCLUSION: Higher vitamin K1 intakes were associated with lower risk for both all-cause and CVD mortality in community-dwelling older women, independent of CVD related risk factors. A higher intake of vitamin K1 rich foods, such as leafy green vegetables, may support cardiovascular health.

Post-bariatric pregnancy is associated with vitamin K1 deficiency, a case control study.

BACKGROUND: Maternal obesity is associated with adverse outcome for pregnancy and childbirths. While bariatric surgery may improve fertility and reduce the risk of certain pregnancy-related complications such as hypertension and gestational diabetes mellitus, there is a lack of evidence on the optimal nutritional monitoring and supplementation strategies in pregnancy following bariatric surgery. We aimed to assess the impact of bariatric surgery on micronutrients in post-bariatric pregnancy and possible differences between gastric bypass surgery and sleeve gastrectomy. METHODS: In this prospective case control study, we recruited 204 pregnant women (bariatric surgery n = 59 [gastric bypass surgery n = 26, sleeve gastrectomy n = 31, missing n = 2] and controls n = 145) from Akershus university hospital in Norway. Women with previous bariatric surgery were consecutively invited to study participation at referral to the clinic for morbid obesity and the controls were recruited from the routine ultrasound screening in gestational week 17-20. A clinical questionnaire was completed and blood samples were drawn at mean gestational week 20.4 (SD 4.5). RESULTS: The women with bariatric surgery had a higher pre-pregnant BMI than controls (30.8 [SD 6.0] vs. 25.2 [5.4] kg/m2, p < 0.001). There were no differences between groups regarding maternal weight gain (bariatric surgery 13.3 kg (9.6) vs. control 14.8 kg (6.5), p = 0.228) or development of gestational diabetes (n = 3 [5%] vs. n = 7 [5%], p = 1.000). Mean levels of vitamin K1 was lower after bariatric surgery compared with controls (0.29 [0.35] vs. 0.61 [0.65] ng/mL, p < 0.001). Multiadjusted regression analyses revealed an inverse relationship between bariatric surgery and vitamin K1 (B -0.26 ng/mL [95% CI -0.51, -0.04], p = 0.047) with a fivefold increased risk of vitamin K1 deficiency in post-bariatric pregnancies compared with controls (OR 5.69 [1.05, 30.77] p = 0.044). Compared with sleeve gastrectomy, having a previous gastric bypass surgery was associated with higher risk of vitamin K1 deficiency (OR 17.1 [1.31, 223.3], p = 0.030). CONCLUSION: Post-bariatric pregnancy is negatively associated with vitamin K1 with a higher risk of vitamin K1 deficiency in pregnancies after gastric bypass surgery compared with after sleeve gastrectomy. Vitamin K1 deficiency in post-bariatric pregnancy have potential risk of hypocoaguble state in mother and child and should be explored in future studies.

Three Different Regimens for Vitamin K Birth Prophylaxis in Infants Born Preterm: A Randomized Clinical Trial.

OBJECTIVE: To study the efficacy of 3 different vitamin K birth prophylaxis regimens in infants born premature. STUDY DESIGN: This was an open-label, parallel-group, randomized clinical trial conducted in a tertiary neonatal care unit in India. Infants born very preterm (≤32 weeks) and/or with very low birth weight (≤1500 g) were included. In each arm, 25 babies were enrolled. Babies were randomized to receive 1.0 mg, 0.5 mg, or 0.3 mg intramuscular (IM) vitamin K1 at birth. Protein induced by vitamin K absence - II (PIVKA-II) levels were assessed at birth, and on days 5 and 28, along with the frequency of death, bleeding manifestations, intraventricular hemorrhage, necrotizing enterocolitis, bilirubin levels, and duration of phototherapy. The primary outcome was comparison of PIVKA-II levels on day 5 of life. RESULTS: All the 3 regimens resulted in similar proportion of vitamin K subclinical sufficiency (PIVKA-II < 0.028 AU/mL) infants on day 5 (1 mg - 100%; 0.5 mg - 91.7%; 0.3 mg - 91.7%, P = .347), with no significant difference in median (IQR) PIVKA-II levels (AU/mL): 1 mg 0.006 (0.004, 0.009); 0.5 mg 0.008 (0.004, 0.009); 0.3 mg 0.006 (0.003, 0.009), P = .301. However, on day 28, there was a significant decrease in the proportion of vitamin K-sufficient infants in the 0.3-mg IM group (72.7%) compared with the 1.0-mg (100%) or 0.5-mg (91.3) groups. The 1.0-mg group had significantly greater bilirubin levels and duration of phototherapy. None of the other clinical outcomes were statistically different. CONCLUSIONS: Both 1-mg and 0.5-mg IM vitamin K birth prophylaxis resulted in high sufficiency on follow-up, compared with 0.3 mg. The current recommendation of 0.5-1 mg IM vitamin K birth prophylaxis for infants born preterm, needs to be continued. TRIAL REGISTRATION: CTRI/2022/02/040396.

The Associations of Dietary Vitamin K Intake and Circulating Vitamin 25(OH)D with Serum Lipoprotein Levels: The Vitamin Deficiency Matters.

A synergistic interplay between vitamins K and D appears to exist. We aimed to investigate for the first time whether the associations of dietary vitamin K intake and circulating 25(OH)D with serum lipoprotein levels are influenced by the existence of deficiency of either or both vitamins K and D. Sixty individuals [24 males, 36(18-79) years old] were examined. Vitamin deficiency of K1 and D were defined as vitamin K1 intake/body weight (BW)<1.00 µg/kg/day and circulating 25(OH)D<20 ng/ml, respectively. In individuals with vitamin K1 deficiency, the vitamin K1 intake/BW correlated positively with high density lipoprotein-cholesterol (HDL-C) (r=0.509, p=0.008) and negatively with serum triglycerides (TG) (r=-0.638, p=0.001), whereas circulating 25(OH)D correlated negatively with TG (r=-0.609, p=0.001). In individuals with vitamin D deficiency, the vitamin K1 intake/BW correlated positively with HDL-C (r=0.533, p=0.001) and negatively with TG (r=-0.421, p=0.009), while circulating 25(OH)D correlated negatively with TG (r=-0.458, p=0.004). The above-mentioned associations of vitamin K1 intake/BW and circulating 25(OH)D with serum lipoproteins were not detected in individuals without vitamin K1 deficiency or the ones without vitamin D deficiency. The vitamin K2 intake/BW correlated negatively with low density lipoprotein-cholesterol (LDL-C) (r=-0.404, p=0.001). In conclusion, the associations of vitamin K1 intake with TG and HDL-C and of circulating 25(OH)D with TG were more pronounced in individuals with deficiency of either or both vitamins K1 and D. Increased dietary vitamin K2 intake was associated with decreased LDL-C.

Inhibit progression of coronary artery calcification with vitamin K in hemodialysis patients (the iPACK-HD study): a randomized, placebo-controlled multi-center, pilot trial.

BACKGROUND: Vitamin K activates matrix Gla protein (MGP), a key inhibitor of vascular calcification. There is a high prevalence of sub-clinical vitamin K deficiency in patients with end-stage kidney disease. METHODS: A parallel randomized placebo-controlled pilot trial was designed to determine whether 10 mg of phylloquinone thrice weekly versus placebo modifies coronary artery calcification progression over 12 months in patients requiring hemodialysis with a coronary artery calcium score (CAC) ≥30 Agatston Units (ClinicalTrials.gov identifier NCT01528800). The primary outcome was feasibility (recruitment rate, compliance with study medication, study completion and adherence overall to study protocol). CAC score was used to assess calcification at baseline and 12 months. Secondary objectives were to explore the impact of phylloquinone on vitamin K-related biomarkers (phylloquinone, dephospho-uncarboxylated MGP and the Gla-osteocalcin to Glu-osteocalcin ratio) and events of clinical interest. RESULTS: A total of 86 patients with a CAC score ≥30 Agatston Units were randomized to either 10 mg of phylloquinone or a matching placebo three times per week. In all, 69 participants (80%) completed the trial. Recruitment rate (4.4 participants/month) and medication compliance (96%) met pre-defined feasibility criteria of ≥4.17 and ≥90%, respectively. Patients randomized to phylloquinone for 12 months had significantly reduced levels of dephospho-uncarboxylated MGP (86% reduction) and increased levels of phylloquinone and Gla-osteocalcin to Glu-osteocalcin ratio compared with placebo. There was no difference in the absolute or relative progression of coronary artery calcification between groups. CONCLUSION: We demonstrated that phylloquinone treatment improves vitamin K status and that a fully powered randomized trial may be feasible.

Evaluation of Response to High-Dose Intravenous Vitamin K Administration.

BACKGROUND: Essential to the coagulation pathway, vitamin K (phytonadione) is used to correct clotting factor deficiencies and for reversal of warfarin-induced bleeding. In practice, high-dose intravenous (IV) vitamin K is often used, despite limited evidence supporting repeated dosing. OBJECTIVE: This study sought to characterize differences in responders and nonresponders to high-dose vitamin K to guide dosing strategies. METHODS: This was a case-control study of hospitalized adults who received vitamin K 10 mg IV daily for 3 days. Cases were represented by patients who responded to the first dose of IV vitamin K and controls were nonresponders. The primary outcome was change in international normalized ratio (INR) over time with subsequent vitamin K doses. Secondary outcomes included factors associated with response to vitamin K and incidence of safety events. The Cleveland Clinic Institutional Review Board approved this study. RESULTS: There were 497 patients included, and 182 were responders. Most patients had underlying cirrhosis (91.5%). In responders, the INR decreased from 1.89 at baseline (95% CI = [1.74-2.04]) to 1.40 on day 3 (95% CI = [1.30-1.50]). In nonresponders, the INR decreased from 1.97 (95% CI = [1.83-2.13]) to 1.85 ([1.72-1.99]). Factors associated with response included lower body weight, absence of cirrhosis, and lower bilirubin. There was a low incidence of safety events observed. CONCLUSIONS: In this study of mainly patients with cirrhosis, the overall adjusted decrease in INR over 3 days was 0.3, which may have minimal clinical impact. Additional studies are needed to identify populations who may benefit from repeated daily doses of high-dose IV vitamin K.

Vitamin K1 inhibits ferroptosis and counteracts a detrimental effect of phenprocoumon in experimental acute kidney injury.

Ferroptosis, a type of iron-dependent programmed cell death distinct from apoptosis, necroptosis, and other types of cell death, is characterized by lipid peroxidation, reactive oxygen species production, and mitochondrial dysfunction. Accumulating evidence has highlighted vital roles for ferroptosis in multiple diseases, including acute kidney injury. Therefore, ferroptosis has become a major focus for translational research. However, despite its involvement in pathological conditions, there are no pharmacologic inhibitors of ferroptosis in clinical use. In the context of drug repurposing, a strategy for identifying new uses for approved drugs outside the original medical application, we discovered that vitamin K1 is an efficient inhibitor of ferroptosis. Our findings are strengthened by the fact that the vitamin K antagonist phenprocoumon significantly exacerbated ferroptotic cell death in vitro and also massively worsened the course of acute kidney injury in vivo, which is of utmost clinical importance. We therefore assign vitamin K1 a novel role in preventing ferroptotic cell death in acute tubular necrosis during acute kidney injury. Since the safety, tolerability, pharmacokinetics, and pharmacodynamics of vitamin K1 formulations are well documented, this drug is primed for clinical application, and provides a new strategy for pharmacological control of ferroptosis and diseases associated with this mode of cell death.

Effect of phylloquinone on indomethacin-induced gastric ulceration in rats: Role of SIRT-1.

Gastric ulcer is the most common gastrointestinal disorder affecting people globally. Although many drugs are available to treat ulcers, the mortality rate is relatively high, and drugs lack selectivity to treat ulcers without causing side effects. In this study, the potential therapeutic effects of phylloquinone were tested against indomethacin-induced gastric ulcer in rats by giving rats a single oral dose of indomethacin (48 mg/kg), followed by phylloquinone (10 mg/kg) orally, once daily for six consecutive days. Phylloquinone significantly attenuated indomethacin-induced oxidative and inflammatory responses through hindering the inflammatory cascade by decreasing the levels of TNF-α, NF-κB, INOS and COX-2 which counteracts indomethacin effects. Also, it increased NAD+ which enhanced SIRT-1 level. Furthermore, phylloquinone was effective in increasing mucus secretion, decreasing acid secretion, reversing histological effects caused by indomethacin and minimizing ulcer and lesion indices All these findings indicate that phylloquinone may be used in protection and treatment of indomethacin-induced gastric ulcer.

Effect of Cefoperazone/Sulbactam on Blood Coagulation Function in Infected Emergency Department Patients and the Necessity of Vitamin K1 (VK1) Preventive Intervention: A Single-Center, Retrospective Analysis.

BACKGROUND Owing to its broad-spectrum antibacterial activity, strong antibacterial effects, and ß-lactamase stability, cefoperazone/sulbactam has been recognized as a first-line empirical drug for treating severe infections. However, its administration is also characterized by numerous adverse effects, including coagulation dysfunction. Here, we summarize past clinical treatment data to provide data support for clinical use of cefoperazone sulbactam. MATERIAL AND METHODS We retrospectively analyzed the clinical medical records of 820 patients treated with cefoperazone/sulbactam from January 2015 to December 2020. A retrospective cohort study design was used. We assessed the general data of patients, age and sex distribution, type of primary disease, and incidence and days of abnormal blood coagulation with cefoperazone sulbactam. The chi-square test and t test were used to analyze the effect of cefoperazone sulbactam on coagulation function and the effect of vitamin K intervention on prognosis. RESULTS The rate of coagulation dysfunction was 24.39% (200 patients). Among these 200 patients, 50 were treated with vitamin K1. With increasing patient age, the number of patients with cefoperazone/sulbactam-induced coagulation dysfunction increased (peak at 81-90 years). APACHE II of coagulation dysfunction (15.54±4.095) was significantly higher than that in the normal group. It occurred at days 2-19 after administration of 9.0 g/day of cefoperazone/sulbactam. Measured coagulation indices were significantly higher after treatment with cefoperazone/sulbactam than before treatment, including international normalized ratio, prothrombin time, and activated partial thrombin time (P<0.0001). CONCLUSIONS All coagulation indices decreased significantly after vitamin K1 intervention, indicating improved coagulation function, especially in patients with high APACHE II scores. Hence, regulated vitamin K1 administration can benefit patients with coagulation dysfunction in clinical treatment.

Determination of Vitamin K1, MK-4, MK-7, and D Levels in Human Serum of Postmenopausal Osteoporosis Women Based on High Stability LC-MS/MS: MK-7 May Be a New Marker of Bone Metabolism.

INTRODUCTION: Vitamin K (VK) as well as vitamin D (VD) plays an important role in osteoporosis. Vitamin K1 (VK1), vitamin K2 (VK2, menaquinone-4 (MK-4), and menaquinone-7 (MK-7)) are significant for the metabolism of skeletal muscle. 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3 (25(OH)D2 and 25(OH)D3) reflect circulating VD levels. More sensitive measurements remain to be developed. In the present study, a new high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of VK1, VK2 (MK-4 and MK-7), as well as 25(OH)D2 and 25(OH)D3 levels in human serum. METHODS: We developed a simple LC-MS/MS method for the determination of VK1, MK-4, MK-7, 25(OH)D2, and 25(OH)D3 levels in human serum and validated the method in a study cohort of 200 patients divided into the premenopausal women group and postmenopausal osteoporosis patient group. RESULTS: The overall precision (coefficient of variation) ranged from 2.66 to 10.11% in the specified working range (0.05-5 ng/mL) for VK1, MK-4, and MK-7. Serum VK1, MK-4, and MK-7 levels in postmenopausal women with osteoporosis were 1.187 ± 0.094 ng/mL, 0.058 ± 0.009 ng/mL, and 0.885 ± 0.064 ng/mL, respectively (mean ± standard deviation). Serum VK1, MK-4, and MK-7 levels in premenopausal women were 1.143 ± 0.103 ng/mL, 0.028 ± 0.003 ng/mL, and 1.553 ± 0.226 ng/mL, respectively. Serum 25(OH)D2 and 25(OH)D3 levels in postmenopausal women with osteoporosis were 0.757 ± 0.056 ng/mL and 11.72 ± 0.632 ng/mL, respectively. Serum 25(OH)D2 and 25(OH)D3 levels in premenopausal were 1.793 ± 0.575 ng/mL and 12.42 ± 1.069 ng/mL, respectively. CONCLUSION: A new LC-MS/MS method for determination of serum VK and VD levels was evaluated and validated. MK-7 in plasma decreased earlier than VD in postmenopausal osteoporosis patients. MK-7 status is significantly associated with osteoporosis and could be considered a predictable biomarker in the diagnosis of osteoporosis in postmenopausal women.

The catalytic mechanism of vitamin K epoxide reduction in a cellular environment.

Vitamin K epoxide reductases (VKORs) constitute a major family of integral membrane thiol oxidoreductases. In humans, VKOR sustains blood coagulation and bone mineralization through the vitamin K cycle. Previous chemical models assumed that the catalysis of human VKOR (hVKOR) starts from a fully reduced active site. This state, however, constitutes only a minor cellular fraction (5.6%). Thus, the mechanism whereby hVKOR catalysis is carried out in the cellular environment remains largely unknown. Here we use quantitative mass spectrometry (MS) and electrophoretic mobility analyses to show that KO likely forms a covalent complex with a cysteine mutant mimicking hVKOR in a partially oxidized state. Trapping of this potential reaction intermediate suggests that the partially oxidized state is catalytically active in cells. To investigate this activity, we analyze the correlation between the cellular activity and the cellular cysteine status of hVKOR. We find that the partially oxidized hVKOR has considerably lower activity than hVKOR with a fully reduced active site. Although there are more partially oxidized hVKOR than fully reduced hVKOR in cells, these two reactive states contribute about equally to the overall hVKOR activity, and hVKOR catalysis can initiate from either of these states. Overall, the combination of MS quantification and biochemical analyses reveals the catalytic mechanism of this integral membrane enzyme in a cellular environment. Furthermore, these results implicate how hVKOR is inhibited by warfarin, one of the most commonly prescribed drugs.

Altered vitamin K biodistribution and metabolism in experimental and human chronic kidney disease.

Chronic kidney disease (CKD) is accompanied with extensive cardiovascular calcification, in part correlating with functional vitamin K deficiency. Here, we sought to determine causes for vitamin K deficiency beyond reduced dietary intake. Initially, vitamin K uptake and distribution into circulating lipoproteins after a single administration of vitamin K1 plus K2 (menaquinone 4 and menaquinone 7, respectively) was determined in patients on dialysis therapy and healthy individuals. The patients incorporated very little menaquinone 7 but more menaquinone 4 into high density lipoprotein (HDL) and low-density lipoprotein particles than did healthy individuals. In contrast to healthy persons, HDL particles from the patients could not be spiked with menaquinone 7 in vitro and HDL uptake was diminished in osteoblasts. A reduced carboxylation activity (low vitamin K activity) of uremic HDL particles spiked with menaquinone 7 vs. that of controls was confirmed in a bioassay using human primary vascular smooth muscle cells. Kidney menaquinone 4 tissue levels were reduced in 5/6-nephrectomized versus sham-operated C57BL/6 mice after four weeks of a vitamin K rich diet. From the analyzed enzymes involved in vitamin K metabolism, kidney HMG-CoA reductase protein was reduced in both rats and patients with CKD. In a trial on the efficacy and safety of atorvastatin in 1051 patients with type 2 diabetes receiving dialysis therapy, no pronounced vitamin K deficiency was noted. However, the highest levels of PIVKA-II (biomarker of subclinical vitamin K deficiency) were noted when a statin was combined with a proton pump inhibitor. Thus, profound disturbances in lipoprotein mediated vitamin K transport and metabolism in uremia suggest that menaquinone 7 supplementation to patients on dialysis therapy has reduced efficacy.