Vitamin K2 (MK-4)

OBJECTIVE: To compare established associations between risk factors and mortality in UK Biobank, a study with an exceptionally low rate of response to its baseline survey, against those from representative studies that have conventional response rates. DESIGN: Prospective cohort study alongside individual participant meta-analysis of other cohort studies. SETTING: United Kingdom. PARTICIPANTS: Analytical sample of 499 701 people (response rate 5.5%) in analyses in UK Biobank; pooled data from the Health Surveys for England (HSE) and the Scottish Health Surveys (SHS), including 18 studies and 89 895 people (mean response rate 68%). Both study populations were linked to the same nationwide mortality registries, and the baseline age range was aligned at 40-69 years. MAIN OUTCOME MEASURE: Death from cardiovascular disease, selected malignancies, and suicide. To quantify the difference between hazard ratios in the two studies, a ratio of the hazard ratios was used with HSE-SHS as the referent. RESULTS: Risk factor levels and mortality rates were typically more favourable in UK Biobank participants relative to the HSE-SHS consortium. For the associations between risk factors and mortality endpoints, however, close agreement was seen between studies. Based on 14 288 deaths during an average of 7.0 years of follow-up in UK Biobank and 7861 deaths over 10 years of mortality surveillance in HSE-SHS, for cardiovascular disease mortality, for instance, the age and sex adjusted hazard ratio for ever having smoked cigarettes (versus never) was 2.04 (95% confidence interval 1.87 to 2.24) in UK Biobank and 1.99 (1.78 to 2.23) in HSE-SHS, yielding a ratio of hazard ratios close to unity (1.02, 0.88 to 1.19). The overall pattern of agreement between studies was essentially unchanged when results were compared separately by sex and when baseline years and censoring dates were aligned. CONCLUSION: Despite a very low response rate, risk factor associations in the UK Biobank seem to be generalisable. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Diabetes mellitus and pre-diabetes are prevalent endocrine disorders associated with substantial morbidity and premature mortality. Vitamin K is known to have several beneficial effects on complications of diabetes and pre-diabetes. However, systematic consolidation of evidence is required to quantify these effects in order to inform clinical practice and research. A systematic search in PubMed, Scopus, Embase, ProQuest, and Google Scholar databases was undertaken from database inception up to October 2018 to evaluate functional roles of different forms of vitamin K on diabetes and pre-diabetes. From 3,734 identified records, nine articles met the inclusion criteria and were evaluated. Vitamin K supplementation was found to be associated with significant reductions in blood glucose (six studies), increased fasting serum insulin (four studies), reduced hemoglobin A1c (three studies), reduced homeostatic model assessment-insulin resistance index (HOMA-IR) (two studies), and increased ß-cell function (two studies) in diabetic animal studies. Following 2-hour oral glucose tolerance test, vitamin K supplementation was observed to be effective in reducing blood glucose and insulin levels in the pre-diabetic population. However, no evidence of effect was observed for fasting blood sugar, insulin, HOMA-IR, and homeostatic model assessment-β-cell function index (two studies). A statistically significant effect was also noted with vitamin K in improving dyslipidemia (three studies) as well as oxidative stress and inflammatory markers (five studies) in diabetic animals. In conclusion, clinical trials and animal studies confirm that vitamin K supplementation may improve both clinical features and complications of diabetes and pre-diabetes. However, quantification of clinical efficacy in the pre-diabetic population and among individuals with comorbidities requires further investigation. © 2019 International Union of Biochemistry and Molecular Biology.

This study assessed whether vitamin K, given with oral bisphosphonate, calcium and/or vitamin D has an additive effect on fracture risk in post-menopausal women with osteoporosis. No difference in bone density or bone turnover was observed although vitamin K1 supplementation led to a modest effect on parameters of hip geometry. PURPOSE: Some clinical studies have suggested that vitamin K prevents bone loss and may improve fracture risk. The aim was to assess whether vitamin K supplementation has an additive effect on bone mineral density (BMD), hip geometry and bone turnover markers (BTMs) in post-menopausal women with osteoporosis (PMO) and sub-optimum vitamin K status receiving bisphosphonate, calcium and/or vitamin D treatment. METHODS: We conducted a trial in 105 women aged 68.7[12.3] years with PMO and serum vitamin K1 ≤ 0.4 µg/L. They were randomised to 3 treatment arms; vitamin K1 (1 mg/day) arm, vitamin K2 arm (MK-4; 45 mg/day) or placebo for 18 months. They were on oral bisphosphonate and calcium and/or vitamin D. We measured BMD by DXA, hip geometry parameters using hip structural analysis (HSA) software and BTMs. Vitamin K1 or MK-4 supplementation was each compared to placebo. Intention to treat (ITT) and per protocol (PP) analyses were performed. RESULTS: Changes in BMD at the total hip, femoral neck and lumbar spine and BTMs; CTX and P1NP did not differ significantly following either K1 or MK-4 supplementation compared to placebo. Following PP analysis and correction for covariates, there were significant differences in some of the HSA parameters at the intertrochanter (IT) and femoral shaft (FS): IT endocortical diameter (ED) (% change placebo:1.5 [4.1], K1 arm: -1.02 [5.07], p = 0.04), FS subperiosteal/outer diameter (OD) (placebo: 1.78 [5.3], K1 arm: 0.46 [2.23] p = 0.04), FS cross sectional area (CSA) (placebo:1.47 [4.09],K1 arm: -1.02[5.07], p = 0.03). CONCLUSION: The addition of vitamin K1 to oral bisphosphonate with calcium and/or vitamin D treatment in PMO has a modest effect on parameters of hip geometry. Further confirmatory studies are needed. TRIAL REGISTRATION: The study was registered at Clinicaltrial.gov:NCT01232647. © 2023. The Auth

Menaquinones (MKs) have been reported to induce apoptosis in rheumatoid arthritis (RA) synovial cells. Recently, menaquinone-4 (MK-4) was proven as a new potential agent for the treatment of RA. However, menaquinone-7 (MK-7) has greater bioavailability and efficacy than MK-4 after oral administration. Yet, the therapeutic benefits of MK-7 in the management of patients with RA have never been addressed. This study was designed to clarify the therapeutic role of MK-7 added to normal therapeutic regimen of RA in patients with different stages of the disease with a clinical follow up through a randomized clinical trial. In a cross sectional study, 84 RA patients (24 male, 60 female) (average age=47.2 years) were enrolled in this study. The patients were divided into MK-7 treated group (n=42) and MK-7 naïve group (n=42). MK-7 capsules were administered in a dose of 100µg/day for three months in the first group without changing in other medications. The clinical and biochemical markers on RA patients treated with MK-7 and naïve group were assessed. In MK-7 treated group, serum concentrations of MK-7 were monitored before and after three months of MK-7 administration. In the cross sectional study, a significant decrease in MK-7 treated group for the levels of undercarboxylated osteocalcin (ucOC), erythrocyte sedimentation rate (ESR), disease activity score assessing 28 joints with ESR (DAS28-ESR), C-reactive protein (CRP) and matrix metalloproteinase (MMP-3) was found. In MK-7 treated group, a marked decrease in RA clinical and biochemical markers for moderate and good response compared to non-responders was observed in ucOC, ESR and DAS28-ESR. A marked increase in the levels of MK-7 for the moderate and good responders compared to non-responders was observed. The results suggest that MK-7 improves disease activity in RA patients. Therefore, MK-7 represents a new promising agent for RA in combination therapy with other disease modifying antirheumatic drugs.

Menaquinone-4 (MK-4) administered at a pharmacological dosage of 45 mg/day has been used for the treatment of osteoporosis in Japan. However, it is not known whether a lower dose of MK-4 supplementation is beneficial for bone health in healthy postmenopausal women. The aim of this study was to examine the long-term effects of 1.5-mg daily supplementation of MK-4 on the various markers of bone turnover and bone mineral density (BMD). The study was performed as a randomized, double-blind, placebo-controlled trial. The participants (aged 50-65 years) were randomly assigned to one of two groups according to the MK-4 dose received: the placebo-control group (n = 24) and the 1.5-mg MK-4 group (n = 24). The baseline concentrations of undercarboxylated osteocalcin (ucOC) were high in both groups (>5.1 ng/ml). After 6 and 12 months, the serum ucOC concentrations were significantly lower in the MK-4 group than in the control group. In the control group, there was no significant change in serum pentosidine concentrations. However, in the MK-4 group, the concentration of pentosidine at 6 and 12 months was significantly lower than that at baseline. The forearm BMD was significantly lower after 12 months than at 6 months in the control group. However, there was no significant decrease in BMD in the MK-4 group during the study period. These results suggest that low-dose MK-4 supplementation for 6-12 months improved bone quality in the postmenopausal Japanese women by decreasing the serum ucOC and pentosidine concentrations, without any substantial adverse effects.

BACKGROUND: Vitamin K₂ contributes to bone and cardiovascular health. Therefore, two vitamin K₂ homologues, menaquinone-4 (MK-4) and menaquinone-7 (MK-7), have been used as nutrients by the food industry and as nutritional supplements to support bone and cardiovascular health. However, little is known about the bioavailability of nutritional MK-4. To investigate MK-4 and MK-7 bioavailability, nutritional doses were administered to healthy Japanese women. FINDINGS: Single dose administration of MK-4 (420 μg; 945 nmol) or MK-7 (420 μg; 647 nmol) was given in the morning together with standardized breakfast. MK-7 was well absorbed and reached maximal serum level at 6 h after intake and was detected up to 48 h after intake. MK-4 was not detectable in the serum of all subjects at any time point. Consecutive administration of MK-4 (60 μg; 135 nmol) or MK-7 (60 μg; 92 nmol) for 7 days demonstrated that MK-4 supplementation did not increase serum MK-4 levels. However, consecutive administration of MK-7 increased serum MK-7 levels significantly in all subjects. CONCLUSIONS: We conclude that MK-4 present in food does not contribute to the vitamin K status as measured by serum vitamin K levels. MK-7, however significantly increases serum MK-7 levels and therefore may be of particular importance for extrahepatic tissues.

Osteocalcin (OC) is a vitamin K-dependent protein found in bone and in circulation. High serum γ-carboxylated OC reflects a high, and high uncarboxylated OC (ucOC) reflects a low vitamin K status. A revolutionary hypothesis is that ucOC acts as a hormone improving glucose handling and reducing fat mass. The objective was to test the logical extrapolation of the ucOC hormone hypothesis to humans that elevated ucOC is associated with higher body weight, BMI and fat mass. In a cross-sectional analysis, the associations of vitamin K status with circulating adiponectin and body composition were investigated in 244 postmenopausal women (study I). The effects of vitamin K treatment on adiponectin, body weight and BMI were investigated in archived samples from forty-two young men and women who received varying doses of menaquinone-7 during 12 weeks (study II) and from a cohort of 164 postmenopausal women who participated in a 3-year placebo-controlled trial on 45 mg menaquinone-4 (MK-4) (study III). No association was found between vitamin K status and circulating adiponectin before or after vitamin K supplementation. A higher carboxylation of OC was significantly correlated with lower body weight, BMI and fat mass of the trunk. Women taking MK-4 maintained their baseline body weight and BMI, whereas women taking placebo showed significant increases in both indices. These findings demonstrate that a high vitamin K status of bone has no effect on circulating adiponectin in healthy people and long-term vitamin K supplementation does not increase weight in healthy postmenopausal women.

It has been reported that treatment with a pharmacological dose (45 mg/d) of menaquinone-4 (MK-4) prevents bone loss in postmenopausal women. However, it is not known whether supplementation with low dose MK-4 has beneficial effects on bone metabolism in healthy women. The aim of this study is to examine the effects of the supplementation of 1.5 mg/d MK-4 for 4 wk on bone and lipid metabolism in healthy postmenopausal Japanese women. The study was performed as a randomized double blind placebo-controlled trial. The participants aged 53-65 y were randomly assigned to 2 groups and supplemented with 1.5 mg/d of MK-4 or a placebo for 4 wk (n=20 for each group). The most marked effects of MK-4 intake were observed on serum osteocalcin (OC) concentrations. Serum undercarboxylated OC (ucOC) concentration decreased, and the gamma-carboxylated OC (GlaOC) and GlaOC/GlaOC+ucOC ratio that indicates the degree of OC gamma-carboxylation increased significantly at 2 and 4 wk compared with that at baseline in the MK-4 group. The serum ucOC and GlaOC concentrations in the MK-4 group were significantly different from those in the placebo group at 2 wk. These results suggest that supplementation with 1.5 mg/d MK-4 accelerated the degree of OC gamma-carboxylation. The concentrations of serum lipids and other indices were not different between the groups at either intervention period. Thus, the additional intake of MK-4 might be beneficial in the maintenance of bone health in postmenopausal Japanese women.

Vitamin K mediates the synthesis of proteins regulating bone metabolism. We have tested whether high vitamin K(2) intake promotes bone mineral density and bone strength. Results showed that K(2) improved BMC and femoral neck width, but not DXA-BMD. Hence high vitamin K(2) intake may contribute to preventing postmenopausal bone loss. INTRODUCTION: Vitamin K is involved in the synthesis of several proteins in bone. The importance of K vitamins for optimal bone health has been suggested by population-based studies, but intervention studies with DXA-BMD as a clinical endpoint have shown contradicting results. Unlike BMC, DXA-BMD does not take into account the geometry (size, thickness) of bone, which has an independent contribution to bone strength and fracture risk. Here we have tested whether BMC and femoral neck width are affected by high vitamin K intake. METHODS: A randomized clinical intervention study among 325 postmenopausal women receiving either placebo or 45 mg/day of vitamin K(2) (MK-4, menatetrenone) during three years. BMC and hip geometry were assessed by DXA. Bone strength indices were calculated from DXA-BMD, femoral neck width (FNW) and hip axis length (HAL). RESULTS: K(2) did not affect the DXA-BMD, but BMC and the FNW had increased relative to placebo. In the K(2)-treated group hip bone strength remained unchanged during the 3-year intervention period, whereas in the placebo group bone strength decreased significantly. CONCLUSIONS: Vitamin K(2) helps maintaining bone strength at the site of the femoral neck in postmenopausal women by improving BMC and FNW, whereas it has little effect on DXA-BMD.

Twenty elderly osteoporotic women with vertebral fracture(s) were randomly allocated to two groups; women in the MK(4) group received calcium with menaquinone 4 (MK(4)) at a dose of 45 mg/day for 2 weeks, and women in the control group received calcium alone for the same period. Serum intact osteocalcin (OC) and undercarboxylated osteocalcin (uc-OC) levels were measured by immunoradiometric assay and enzyme immunoassay, respectively, at baseline and on the 7th and 14th days following the start of the treatment. There were no differences in the baseline data including age, weight, phylloquinone, menaquinone 4, menaquinone 7, OC, and uc-OC levels between the MK(4) group and the control group. Administration of MK(4) significantly raised the MK(4) level from 0.20 +/- 0.10 (mean +/- SE) pg/ml to 15.09 +/- 5.62 pg/ml ( P < 0.04), and reduced serum uc-OC levels from 2.80 +/- 0.93 ng/ml to 1.76 +/- 0.56 ng/ml ( P < 0.05) at the end of the study, respectively. No significant changes in these levels were observed in the control group. Serum OC levels were stable during the period in both groups. In this randomized prospective study, the MK(4) group shows a reduction in the serum uc-OC level within 2 weeks without any significant change in OC, suggesting that the uc-OC is changed to carboxylated OC. This early effect of MK(4) on bone metabolism may be estimated by the measurement of serum uc-OC in elderly osteoporotic women with vertebral fractures.

Erratum in Bone. 2008 Jul;43(1):217. Retraction in Bone. 2018 Jan;106:212. doi: 10.1016/j.bone.2017.10.006. Significant reduction in bone mineral density (BMD) occurs in patients with Parkinson's disease (PD), correlating with immobilization and with vitamin D deficiency, and increasing the risk of hip fracture, especially in elderly women. As a biological indicator of compromised vitamin K status, an increased serum concentration of undercarboxylated osteocalcin (Oc) has been associated with reduced BMD in the hip and an increased risk of fracture in otherwise healthy elderly women. We evaluated treatment with vitamin K(2) (menatetrenone; MK-4) in maintaining BMD and reducing the incidence of nonvertebral fractures in elderly female patients with PD. In a random and prospective study of PD patients, 60 received 45 mg of MK-4 daily for 12 months, and the remaining 60 (untreated group) did not. At baseline, patients of both groups showed vitamin D and K(1) deficiencies, high serum levels of ionized calcium, and glutaminic residue (Glu) Oc, and low levels of parathyroid hormone (PTH) and 1,25-dihydroxyvitamin D [1,25-(OH)(2)D], indicating that immobilization-induced hypercalcemia inhibits renal synthesis of 1,25-(OH)(2)D and compensatory PTH secretion. BMD in the second metacarpals increased by 0.9% in the treated group and decreased by 4.3% in the untreated group (p < 0.0001). Vitamin K(2) level increased by 259.8% in the treated group. Correspondingly, significant decreases in Glu Oc and calcium were observed in the treated group, in association with an increase in both PTH and 1,25-(OH)(2)D. Ten patients sustained fractures (eight at the hip and two at other sites) in the untreated group, and one hip fracture occurred among treated patients (p = 0.0082; odds ratio = 11.5). The treatment with MK-4 can increase the BMD of vitamin D- and K-deficient bone by increasing vitamin K concentration, and it can also decrease calcium levels through inhibition of bone resorption, resulting in an increase in 1,25-(OH)(2)D concentration.

Significant reduction in bone mineral density (BMD) occurs in stroke patients on the hemiplegic and contralateral sides, correlating with the degree of paralysis and vitamin D and K deficiency due to malnutrition, and increasing the risk of hip fracture. We evaluated the efficacy of vitamin K2 (menatetrenone: menaquinone-4; MK-4) in maintaining BMD by comparing serum biochemical indices of bone metabolism between treated and untreated patients. In a random and prospective study, of 108 hemiplegic patients following stroke, 54 received 45 mg menatetrenone daily (MK-4 group, n = 54) for 12 months, and the remaining 54 (untreatment group) did not. Nine patients excluded from the study. The BMD in the second metacarpals and serum indices of bone metabolism were determined. BMD on the hemiplegic side increased by 4.3% in the MK-4 group and decreased by 4.7% in the untreated group (p < 0.0001), while BMD on the intact side decreased by 0.9% in the MK-4 group and by 2.7% in the untreated group (p < 0.0001). At baseline, patients of both groups showed vitamin D and K1 deficiencies, high serum levels of ionized calcium, pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP), and low levels of parathyroid hormones (PTH) and bone Gla proteins (BGP), indicating that immobilization-induced hypercalcemia inhibits renal synthesis of 1, 25-dihydroxyvitamin D (1, 25-[OH]2D) and compensatory PTH secretion. Both vitamins K1 and K2 increased by 97.6% and 666.9%, respectively, in the MK-4 group. Correspondingly, a significant increase in BGP and decreases in both ICTP and calcium were observed in the MK-4 group, in association with a simultaneous increase in both PTH and 1, 25-[OH]2D. One patient in the untreated group suffered from a hip fracture, compared with none in the MK-4 group. The treatment with MK-4 can increase the BMD of disused and vitamin D- and K-deficient hemiplegic bone by increasing the vitamin K concentration, and it also can decrease calcium levels through inhibition of bone resorption, resulting in an increase in 1, 25-[OH]2D concentration.

This double-blinded randomised controlled trial investigated whether menaquinones (MK) producing probiotics for 12 weeks improve vitamin K status, compared with placebo in 50-75 years old with at least one cardiovascular risk factor. Twenty participants were randomised to either MK-producing probiotics (n = 10) or placebo (n = 10). Plasma dephosphorylated-uncarboxylated matrix gla protein (dp-ucMGP) concentrations were the primary study outcome and determined at baseline, six and twelve weeks by a chemiluminescent InaKtif MGP assay, and analysed by linear mixed models. Secondary outcomes included serum MK-7 and phylloquinone and stool MK-4 to MK-10 and phylloquinone, assessed by linear regression. Three participants dropped out (two placebo, one intervention). Compliance was high; median 98% [IQR 96-99] and 90% [IQR 74-96] sachets used in intervention vs placebo arm. At 6 weeks, dp-ucMGP was significantly lower in the intervention group (-75.69 [95%-CI -128.37; -22.92] pmol/l), but this difference diminished by 12 weeks (-38.63 [95%-CI -94.49; 16.14] pmol/l) due to a reduction in the placebo group. Overall, the mean dp-ucMGP change over 12 weeks favoured the intervention (-59.89 [95%-CI -110.7; -9.187] pmol/l). Statistically significant differences in secondary outcomes included higher serum MK-7, and faecal MK-6 and MK-7 concentrations in the probiotic vs placebo arm (e.g. 4.41 [95%-CI 2.17; 6.65] μg/L for serum MK-7). No other secondary outcomes differed significantly. MK producing probiotics may enhance vitamin K status in older adults at elevated cardiovascular risk. Larger, longer-term studies are needed to assess functional outcomes. The Netherlands Trial Register: NTR7505, 27-09-2018.

Late-onset hypogonadism (LOH) is an age-related condition characterized by a decline in testosterone (Ts) levels and associated symptoms that impair quality of life in older men. Although Ts replacement therapy is available, its clinical use is limited by adverse effects. Vitamin K (VK) is a fat-soluble vitamin that functions as a cofactor for γ-glutamylcarboxylase and plays important roles in blood coagulation and bone homeostasis. Menaquinone-4 (MK-4), a VK homolog predominantly found in animal-derived foods, has been shown to enhance Ts production in healthy male rats. However, whether this effect occurs under low-Ts conditions remains unclear. In this study, we investigated the effects of VK on LOH using a leuprorelin acetate (LA)-induced low-Ts rat model. Male Sprague-Dawley rats were administered sustained-release LA and fed a control diet or diets supplemented with VK1 or MK-4 (75 mg/kg) for 4 weeks. Compared with the control group, MK-4 supplementation significantly ameliorated the reduction in serum Ts levels and seminiferous tubule diameter, whereas VK1 supplementation showed no significant effects. Furthermore, MK-4 supplementation activated the protein kinase A signaling pathway, which is directly involved in testicular Ts production. These findings suggest that MK-4 supplementation may represent a novel nutritional strategy for the management of LOH.

Ferrite nanoparticles (FNPs), especially copper ferrite nanoparticles (CuFe₂O₄ NPs), are a promising platform in nanomedicine for targeted cancer treatment. Consequently, unique CuFe₂O₄ NPs were functionalized with a bioactive extract derived from Salinicoccus sp. RM1, a halophilic bacterial strain obtained from the Red Sea. The bacterial extract, abundant in menaquinone (MK) homologs (MK-4 to MK-13) as verified by LC-QTOF-MS, used as an excellent functionalizing agent to produced MK-loaded nanoparticles (CuFe₂O₄ NPs-MK). Prepared NPs were analyzed using XRD, FT-IR, SEM, EDX, particle size analysis and magnetic susceptibility analysis, confirming the effective production and functionalization of the NPs. CuFe2O4 NPs modified with MK exhibited significant cytotoxicity against MCF-7 cells, yielding an IC₅₀ of 48.94 µg/ml and a notable 45% reduction in BCL-2 expression, while BAX expression experienced a marginal 3.4% rise. This study demonstrates its strength in innovative design and comprehensive characterization of a novel anti-cancer nanocomposite (CuFe₂O₄ NPs-MK), utilizing sustainably sourced marine MKs to induce apoptosis in breast cancer cells by modulating the BAX/BCL-2 gene ratio. © 2025. The Author(s).

Bacterial leaf blight (BLB), caused by Xanthomonas oryzae pv. oryzae (Xoo), remains a major threat to global rice production. In this study, we identified the novel small-molecule compound PK150 with potent antibacterial activity against Xoo. PK150 exhibits a minimum inhibitory concentration (MIC) of 0.15 μg/mL in vitro, and achieved 78% protective efficacy at 200 μg/mL in planta. Mechanistic studies revealed that PK150 targets menaquinone biosynthesis by binding to demethylmenaquinone methyltransferase (MenG), which is a key enzyme in this pathway. Surface plasmon resonance (SPR) analysis confirmed that PK150 binds to MenG, with a dissociation constant (Kd) of 6.42 × 10-5 M. The antibacterial effect of PK150 was markedly reduced by the addition of 100 μg/mL exogenous menaquinone-4 (MK-4) and overexpression of MenG. Moreover, molecular docking analysis identified ALA-73, THR-76, ASP-97, and ILE-98 as key residues involved in the PK150-MenG interaction, which was further validated by SPR assays showing loss of binding to a MenG mutant. Phylogenetic analysis revealed that the sequence of MenG in Xoo showed significant evolutionary differences from those of other Gram-negative bacteria. These findings highlight PK150 as a promising candidate for the development of novel agrochemicals to manage BLB.

Menaquinone-4 (MK-4), a subtype of vitamin K2 (VK2), is associated with bone metabolism, blood coagulation and anti-inflammation. Atherosclerosis develops and progresses as oxidized low-density lipoprotein (oxLDL) uptake in macrophages via scavenger receptors, leading to the formation of foam cells and vulnerable plaques. However, the effects of MK-4 on macrophages in atherosclerosis and on oxLDL uptake in macrophages remain unclear. This study investigated the effects of MK-4 on atherosclerotic plaque formation and vulnerability, focusing on macrophage function and plaque stability. In apolipoprotein E (ApoE) knockout (KO) mice, oral MK-4 (15 mg/kg/day) significantly inhibited atherosclerotic plaque formation in the aorta. MK-4 also stabilized plaques by reducing foam cell accumulation and preventing fibrous cap disruption without altering plasma cholesterol levels. In vitro, MK-4 (0-30 μM) dose-dependently suppressed oxLDL uptake in macrophages, a key factor in foam cell formation. Additionally, MK-4 (30 μM) significantly reduced the lipopolysaccharide (LPS)-induced expression of scavenger receptors (SR-A and CD36) and proinflammatory cytokines (TNF-α and OPN), as well as blocked the activation of MAP kinases (p38, JNK, and ERK) caused by LPS stimulation. Notably, JNK inhibition played a central role in reducing the expression of inflammatory markers and scavenger receptors. In conclusion, MK-4 suppresses foam cell formation and inflammation by blocking MAP kinase signaling in macrophages, thereby preventing the progression and destabilization of atherosclerotic plaques. These findings suggest that MK-4 may be useful for preventing the onset of cardiovascular diseases, such as myocardial infarction and unstable angina.

Vitamin K, primarily known for its roles in coagulation and bone metabolism, has recently been implicated in neuroprotection and neuronal differentiation, particularly via its bioactive form, menaquinone-4 (MK-4). Here, we synthesized 12 vitamin K compounds with retinoic acid-conjugated side chains and methyl ester modifications to enhance neuroactive properties. Among these, compound 7 demonstrated superior stability, robust transcriptional activation via steroid and xenobiotic receptor and retinoic acid receptor, and efficient induction of neuronal differentiation in mouse neural progenitor cells. Mechanistic analyzes revealed that Vitamin K activates metabotropic glutamate receptor 1 (mGluR1). Docking simulations confirmed its stronger mGluR1-binding affinity compared to MK-4. In vivo pharmacokinetics in C57BL/6 mice showed effective blood-brain barrier penetration, with compound 7 metabolizing into MK-4 over time. These findings establish compound 7 as a promising candidate for neurodegenerative disease therapies through its unique neuroactive mechanisms.

Excessive reactive oxygen species (ROS) levels cause oxidative stress, which can lead to various diseases. Renal failure is associated with oxidative stress and mitochondrial dysfunction. Vitamin K1 (phylloquinone) and K2 (menaquinone) are essential for blood coagulation and bone formation. Vitamin K has been shown to have anti-inflammation, glucose metabolism regulation, and antiferroptosis functions. We investigated the impact of menaquinone-4 (MK-4) on oxidative stress and mitochondrial dysfunction in human renal proximal tubular cells. MK-4 protected cells from oxidative damage induced by l-buthionine-(S,R)-sulfoximine (BSO), a selective inhibitor of glutathione metabolism, by inhibiting cell death, mitochondrial ROS production, and lipid peroxidation. MK-4 also reduced lactate production, prevented mitochondrial fragmentation, and improved mitochondrial respiratory function, indicating cytoprotective effects. Moreover, it enhanced intracellular ATP production and respiratory capacity, even in the absence of oxidative stress. Thus, MK-4 plays an important role in mitochondrial function in renal proximal tubular cells.

Schnyder corneal dystrophy (SCD) is a rare autosomal dominant condition characterized by the opacification of the cornea owing to the abnormal deposition of cholesterol. SCD-associated mutations have been identified in the gene encoding UbiA prenyltransferase domain-containing protein-1 (UBIAD1), which uses geranylgeranyl pyrophosphate (GGpp) to synthesize the vitamin K2 subtype menaquinone-4 (MK-4). Beyond its enzymatic role, UBIAD1 serves as a key regulator of the endoplasmic reticulum (ER)-localized enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR), the rate-limiting enzyme in the mevalonate pathway that produces cholesterol and nonsterol isoprenoids such as GGpp and MK-4. Sterol-induced binding to UBIAD1 inhibits the sterol-accelerated ER-associated degradation (ERAD) of HMGCR to maintain the synthesis of nonsterol isoprenoids under conditions of cholesterol repletion. GGpp dissociates the HMGCR-UBIAD1 complex, triggering maximal ERAD of HMGCR and ER-to-Golgi translocation of UBIAD1. However, SCD-associated UBIAD1 resists this GGpp-induced dissociation and remains sequestered in the ER. ER retention of UBIAD1 leads to inhibition of HMGCR ERAD, promoting increased synthesis and accumulation of cholesterol. Here, chemical genetic screening was utilized to identify molecules that restored Golgi localization of SCD-associated UBIAD1 (N102S) and thereby relieve inhibition of HMGCR ERAD. We found that the chemotherapeutic tyrosine kinase inhibitor Apatinib stimulated ER-to-Golgi transport of both N102S and wild type UBIAD1. This effect required GGpp but was independent of Apatinib's tyrosine kinase inhibition. Apatinib-mediated Golgi transport of UBIAD1 enhanced the ERAD of HMGCR. Photoaffinity labeling studies indicated that Apatinib binds directly to UBIAD1, suggesting that the drug allosterically activates GGpp-induced transport of UBIAD1 from the ER to the Golgi.

BACKGROUND: Menaquinone 4 (MK-4) is the primary form of vitamin K found in the brain. In rodent studies, treatment with the vitamin K-antagonist warfarin lowered brain MK-4 concentrations. OBJECTIVES: It is not known whether brain MK-4 levels are influenced by warfarin treatment in humans. To address this, we compared postmortem brain MK-4 concentrations in older adults treated with warfarin prior to death to older adults not treated with warfarin. We also determined the likelihood of having mild cognitive impairment (MCI) or dementia in warfarin users, compared to nonusers. METHODS: We used data from 381 autopsied participants, 76% female, mean (SD) age at death 92(6) y, in the Rush Memory and Aging Project (MAP) in whom MK-4 was measured in 4 brain regions: the mid-frontal and temporal cortices, anterior watershed (AWS), and cerebellum. Brain MK-4 concentrations were compared between those treated with warfarin and those not treated, using linear regression adjusted for age, sex, and cognitive diagnosis at death. The association of warfarin use prior to death with cognitive diagnosis at death was evaluated using logistic regression, adjusted for age, sex, education, and apolipoprotein E4 status. RESULTS: Warfarin users [n = 73, median (IQR) duration of warfarin use = 585 (479-656) d] had 68%-79% lower brain MK-4 concentrations in all measured regions, and the mean across all regions, compared with nonwarfarin users (unstandardized β -1.538 to -1.140; all P < 0.001, fully adjusted). The likelihood of having MCI or dementia, compared with no cognitive impairment, at death did not significantly differ between those treated with warfarin prior to death and those not [OR (95% confidence interval) for MCI: 0.82 (0.41, 1.62), dementia: 1.04 (0.57, 1.93), fully adjusted]. CONCLUSIONS: These findings suggest that warfarin treatment influences MK-4 concentrations in the human brain. Future studies are needed to elucidate the mechanisms underlying this effect and its clinical implications.

Vitamin K3 (VK3) is an essential micronutrient for fish growth and metabolism. To determine the optimal required dietary concentration of VK, a 12-week-long trial was planned to investigate the impact of VK3 on growth performance, muscle composition, liver menaquinone-4 (MK-4), whole-body MK-4 concentration, and antioxidant capacity (T-AOC) in coho salmon alevins. A total of 2100 coho salmon alevins were divided into twenty-one tanks, with 100 alevins in each tank, and three tanks represented one group. Each of the seven groups were randomly assigned to one of the experimental diets formulated with varying levels of menadione nicotinamide bisulphite (VK3), i.e., 0.16 (control), 5.25, 10.22, 14.93, 20.51, 40.09, and 59.87 mg/kg, respectively. The results revealed that the inclusion of VK3 from 5.25 to 40.09 mg/kg improved (p < 0.05) the survival rate (SR), weight gain (WG), specific growth rate (SGR), and feed conversion ratio (FCR), while no effect (p > 0.05) was observed on the hepatosomatic index (HSI), viscerosomatic index (VSI), Fulton's condition factor (K), and muscle composition. The whole-body MK-4, liver MK-4, liver T-AOC, total superoxide dismutase (T-SOD), and catalase (CAT) enzymes were also increased (p < 0.05). Malondialdehyde (MDA) contents were reduced (p < 0.05) in all supplemented groups with a decreasing trend. The predicted optimal required dietary concentrations of VK3 were found to be 34.0, 43.5, 38.54, and 31.97 mg/kg based on WG, SGR, liver MK-4 concentration, and T-AOC, respectively, by quadratic regression analysis. It is concluded that the dietary VK3 has improved the growth performance and antioxidant status in alevins during early development in the range of 31.97 to 43.5 mg/kg diet.

While the plasma phylloquinone (PK) concentration is inversely correlated with cardiovascular risk, the involvement of PK in regulating endothelial function has not been directly investigated. Therefore, in this study we assessed the effects of short-term treatment with PK-deficient diets (5-10 weeks) on endothelial function in normolipidemic 14-week-old male C57BL/6JCmd mice and age-matched dyslipidaemic male E3L.CETP mice. Our results show that in normolipidemic mice dietary PK deficiency was associated with a marked reduction of PK levels in the plasma and liver (liquid chromatography-mass spectrometry measurements) and with impaired endothelium-dependent vasodilation assessed in vivo by magnetic resonance imaging (MRI). Dietary PK deficiency-induced endothelial dysfunction was fully reversed by PK supplementation. In dyslipidaemic E3L.CETP mice, dietary PK deficiency exacerbated preexisting endothelial dysfunction. Furthermore, dietary PK deficiency decreased menaquinone-4 (MK-4) levels in the aorta but did not affect blood coagulation (calibrated automated thrombography), microbiota composition (culturing and next-generation sequencing), and gut menaquinone production. In conclusion, our study demonstrated for the first time that sufficient dietary PK intake supports endothelial function in normolipidemic and dyslipidaemic mice indicating nutritional significance of dietary PK in the maintenance of endothelial function in humans.

This study explored the short-term effects of vitamin K2 (VK2) supplementation on biochemical parameters (vitamin D, vitamin E, vitamin A, alkaline phosphatase, calcium, phosphorus (P), magnesium, metallothionein, triglycerides, cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and lipoprotein fractions (albumin, HDL, very low-density lipoprotein (VLDL), LDL, and chylomicrons). A short-term experiment (24 h, six probands) was performed to track changes in VK2 levels after a single-dose intake (360 µg/day). Liquid chromatography-tandem mass spectrometry was used to monitor vitamin K levels (menaquinone-4 (MK-4), menaquinone-7 (MK-7), and vitamin K1 [VK1]) with a limit of detection of 1.9 pg/mL for VK1 and 3.8 pg/mL for the two forms of VK2. Results showed that MK-7 levels significantly increased within 2-6 h post-administration and then gradually declined. MK-4 levels were initially low, showing a slight increase, whereas VK1 levels rose initially and then decreased. Biochemical analyses indicated no significant changes in sodium, chloride, potassium, calcium, magnesium, albumin, or total protein levels. A transient increase in P was observed, peaking at 12 h before returning to baseline. Agarose gel electrophoresis of lipoprotein fractions revealed distinct chylomicron bands and variations in VLDL and HDL mobility, influenced by dietary lipids and VK2 supplementation. These findings suggest effective absorption and metabolism of MK-7 with potential implications for bone metabolism and cardiovascular health. © 2024 Wiley‐VCH GmbH.

Vitamin K (VK) is an essential micronutrient impacting many systems in the body. This lipid-soluble vitamin is found in various plant and animal products and is absorbed via the lymphatic system. This biomolecule's importance to human health includes but is not limited to its promotion of brain, cardiovascular, bone, and immune functions. These biological properties are also necessary for maintaining domesticated animal health. The synergistic impact of both VK and vitamin D (VD) maximizes these health benefits, specifically for the circulatory and skeletal systems. This manuscript reviews VK's properties, molecular structures, nutrikinetics, mechanisms of action, daily requirements, safety in supplemental form, biomarkers used for its detection, and impacts on various organs. The purpose of synthesizing this information is to evaluate the potential uses of VK for the treatment or prevention of diseases.

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.

Sarcopenic obesity, low muscle mass, and high body fat are growing health concerns in the aging population. This review highlights the need for standardized criteria and explores nutraceuticals as potential therapeutic agents. Sarcopenic obesity is associated with insulin resistance, inflammation, hormonal changes, and reduced physical activity. These factors lead to impaired muscle activity, intramuscular fat accumulation, and reduced protein synthesis, resulting in muscle catabolism and increased fat mass. Myostatin and irisin are myokines that regulate muscle synthesis and energy expenditure, respectively. Nutritional supplementation with vitamin D and calcium is recommended for increasing muscle mass and reducing body fat content. Testosterone therapy decreases fat mass and improves muscle strength. Vitamin K, specifically menaquinone-4 (MK-4), improves mitochondrial function and reduces muscle damage. Irisin is a hormone secreted during exercise that enhances oxidative metabolism, prevents insulin resistance and obesity, and improves bone quality. Low-glycemic-index diets and green cardamom are potential methods for managing sarcopenic obesity. In conclusion, along with exercise and dietary support, nutraceuticals, such as vitamin D, calcium, vitamin K, and natural agonists of irisin or testosterone, can serve as promising future therapeutic alternatives.

Long-term usage of bisphosphonates, especially zoledronic acid (ZA), induces osteogenesis disorders and medication-related osteonecrosis of the jaw (MRONJ) in patients, thereby contributing to the destruction of bone remodeling and the continuous progression of osteonecrosis. Menaquinone-4 (MK-4), a specific vitamin K2 isoform converted by the mevalonate (MVA) pathway in vivo, exerts the promotion of bone formation, whereas ZA administration suppresses this pathway and results in endogenous MK-4 deficiency. However, no study has evaluated whether exogenous MK-4 supplementation can prevent ZA-induced MRONJ. Here we showed that MK-4 pretreatment partially ameliorated mucosal nonunion and bone sequestration among ZA-treated MRONJ mouse models. Moreover, MK-4 promoted bone regeneration and inhibited osteoblast apoptosis in vivo. Consistently, MK-4 downregulated ZA-induced osteoblast apoptosis in MC3T3-E1 cells and suppressed the levels of cellular metabolic stresses, including oxidative stress, endoplasmic reticulum stress, mitochondrial dysfunction, and DNA damage, which were accompanied by elevated sirtuin 1 (SIRT1) expression. Notably, EX527, an inhibitor of the SIRT1 signaling pathway, abolished the inhibitory effects of MK-4 on ZA-induced cell metabolic stresses and osteoblast damage. Combined with experimental evidences from MRONJ mouse models and MC3T3-E1 cells, our findings suggested that MK-4 prevents ZA-induced MRONJ by inhibiting osteoblast apoptosis through suppression of cellular metabolic stresses in a SIRT1-dependent manner. The results provide a novel translational direction for the clinical application of MK-4 for preventing MRONJ.

BACKGROUND: Vitamin K is involved in the formation of coronary artery calcification which is an independent predictor of coronary heart disease. This study aims to explore the association between coronary artery calcification score and serum concentrations of vitamin K1, menaquinone-4 (MK-4) and menaquinone-7 (MK-7) in middle-aged and elderly Chinese population. METHODS: A total of 116 patients who underwent CT coronary angiography were consecutively enrolled. Serum concentrations of vitamin K1, MK-4 and MK-7 were determined by high performance liquid chromatography tandem mass spectrometry. The relationships between coronary artery calcification score and serum vitamin K concentrations were analyzed. RESULTS: Significantly lower serum vitamin K1 concentration was found in the patients with CACS > 400, comparing with the other CACS categories, respectively. Log (CACS + 1) was significantly higher in MK-4 < 0.05 ng/ml group compared with MK-4 ≥ 0.05 ng/ml group [2.03(0.21, 2.58) vs 1.31(0.00, 2.19), P < 0.05]. In subjects with established coronary calcification (defined as CACS > 10), vitamin K1 was found to be an independent factor contributing to higher CACS (r = -0.288, P = 0.013). CONCLUSIONS: In this retrospective analysis, serum vitamin K1 and MK-4 concentrations were significantly lower in middle-aged and elderly cohorts with increasing calcification scores. The significant effect of vitamin K1 on CACS was only found in individuals who already had calcification. Whether the detection of circulating vitamin K in patients with preexisting coronary calcification could guide vitamin K supplementation needs further exploration.

This study was to examine the effects of dietary vitamin K (VK) 3 supplementation on immune-related substances in milk, oxidative stress indices in plasma and VK1, and menaquinone 4 (MK-4) in plasma and milk in periparturient dairy cows. Forty healthy perinatal Holstein-Friesian dairy cows were used in this study. Twenty-one animals were randomly selected and categorized into the VK3 supplemented (50 mg/day/head as VK3) group; the remaining 19 were categorized into the control group. On day 3 after calving, blood and milk were sampled, and their chemical components were determined. The VK3 supplemented group had significantly higher menaquinone 4 levels in plasma and milk on day 3 postpartum than the control group. In addition, there was a significant increase in the immunoglobulin G (IgG) level in milk. VK3 may be absorbed from the gastrointestinal tract and converted to MK-4, the biologically active form of VK, in the mammary gland and other tissues. It was thought that the increase in MK-4 level in plasma and milk induced an increase in the concentration of IgG in milk. VK3 supplementation to periparturient dairy cows may contribute to the production of colostrum with high concentrations of IgG and MK-4. © 2022 Japanese Society of Animal Science.