Vitamin K‑dependent proteins involved in bone and cardiovascular health (Review)

Vitamin K for Vascular Calcification in Kidney Patients: Still Alive and Kicking, but Still a Lot to Learn

Patients with chronic kidney disease (CKD) suffer disproportionately from a high burden of cardiovascular disease, which, despite recent scientific advances, remains partly understood. Vascular calcification (VC) is the result of an ongoing process of misplaced calcium in the inner and medial layers of the arteries, which has emerged as a critical contributor to cardiovascular events in CKD. Beyond its established role in blood clotting and bone health, vitamin K appears crucial in regulating VC via vitamin K-dependent proteins (VKDPs). Among these, the matrix Gla protein (MGP) serves as both a potent inhibitor of VC and a valuable biomarker (in its inactive form) for reflecting circulating vitamin K levels. CKD patients, especially in advanced stages, often present with vitamin K deficiency due to dietary restrictions, medications, and impaired intestinal absorption in the uremic environment. Epidemiological studies confirm a strong association between vitamin K levels, inactive MGP, and increased CVD risk across CKD stages. Based on the promising results of pre-clinical data, an increasing number of clinical trials have investigated the potential benefits of vitamin K supplementation to prevent, delay, or even reverse VC, but the results have remained inconsistent.

The Potential of Vitamin K as a Regulatory Factor of Bone Metabolism-A Review

Vitamin K (VK), a fat-soluble vitamin, is essential for the clotting of blood because of its role in the production of clotting factors in the liver. Moreover, researchers continue to explore the role of VK as an emerging novel bioactive molecule with the potential function of improving bone health. This review focuses on the effects of VK on bone health and related mechanisms, covering VK research history, homologous analogs, dietary sources, bioavailability, recommended intake, and deficiency. The information summarized here could contribute to the basic and clinical research on VK as a natural dietary additive and drug candidate for bone health. Future research is needed to extend the dietary VK database and explore the pharmacological safety of VK and factors affecting VK bioavailability to provide more support for the bone health benefits of VK through more clinical trials.

Risk of osteoporosis in patients treated with direct oral anticoagulants vs. warfarin: an analysis of observational studies

Aims

Evidence on the association between the risk of new-onset osteoporosis and oral anticoagulants remains controversial. We aimed to compare the risk of osteoporosis associated with the use of direct oral anticoagulants (DOACs) with that associated with warfarin use.

Methods

Studies published up to 15 March 2023 that investigated the association between the use of DOACs and warfarin and the incidence of osteoporosis were identified by online searches in PubMed, Embase, the Cochrane Library, and Web of Science conducted by two independent investigators. Random-effects or fixed-effect models were employed to synthesize hazard ratios (HRs)/relative ratios (RRs) with 95% confidence intervals (CIs) for estimating the risk of osteoporosis correlated with DOAC and warfarin prescriptions (PROSPERO No. CRD42023401199).

Results

Our meta-analysis ultimately included four studies involving 74,338 patients. The results suggested that DOAC use was associated with a significantly lower incidence of new-onset osteoporosis than warfarin use (pooled HR: 0.71, 95% CI: 0.57 to 0.88, p < 0.001, I 2: 85.1%). Subanalyses revealed that rivaroxaban was associated with a lower risk of osteoporosis than both warfarin and dabigatran. In addition, DOACs were associated with a lower risk of developing osteoporosis than warfarin in both male and female patients, in patients with atrial fibrillation (AF), and in patients who underwent therapy for > 365 days.

Conclusion

DOAC users experienced a lower incidence of osteoporosis than warfarin users. This study may give us insight into safe anticoagulation strategies for patients who are at high risk of developing osteoporosis.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO, identifier CRD42023401199.

Animal protein-soybean oil-based broiler diet optimizes net profit at the expense of desirable ω-6 fatty acids from the breast muscle of the broiler chicken

Total 288 Ross-308-day-old male broiler chicks were randomly distributed into six dietary treatment groups in a two-way ANOVA with 2 × 3 factorial arrangements (two factors, i.e., dietary protein and energy having two types of protein, e.g., plant, animal and three different sources of energy, e.g., soybean oil, rice bran oil and sunflower oil) to justify if animal protein-soybean oil based broiler diet optimizes net profit at the expense of desirable ω-6 fatty acids in the breast muscle of the broiler chicken. Average daily feed intake (ADFI), final live weight (FLW), average daily gain (ADG), feed efficiency (FE), carcass characteristics, cardio-pulmonary morphometry, fatty acid profile of the breast muscle and cost-benefit analysis were measured. Results indicated that animal protein significantly increased 4.27% FLW, 6.13% ADFI, 4.31% ADG and 2.93% wing weight. Accordingly, soybean oil increased 4.76% FLW, 3.80% ADG and 1.36% dressing percentage at the expense of 12.07% proventriculus weight compared with sunflower oil. The generalized linear model identified no interaction effects of the sources of protein and energy on overall performance of the birds. Replacement of vegetable protein by animal protein decreased 14.01% ∑ω-3, 12.16% ∑ω-6 and 12.21% sum of polyunsaturated fatty acids (∑PUFA) and concomitantly increased 10.82% sum of saturated fatty acids (∑SFAs) in the breast muscle (Pectoralis major). Accordingly, replacement of sunflower oil by soybean oil decreased 29.17% ∑ω-3, 6.71% ∑ω-6, 11.62% sum of monounsaturated fatty acids (∑MUFAs) and 7.33% ∑PUFAs and concurrently increased 18.36% ∑SFAs in the breast muscle of the broiler birds. It was concluded that animal protein-soybean oil-based broiler diet optimized net profit at the expense of desirable ω-3 and ω-6 fatty acids in the breast muscle of the broiler chicken.

The additive effect of vitamin K supplementation and bisphosphonate on fracture risk in post-menopausal osteoporosis: a randomised placebo controlled trial

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.

Medial Sclerosis-Epidemiology and Clinical Significance

BACKGROUND

Medial sclerosis (MeS) is a chronic systemic vascular disease that mainly affects the arteries of the lower limb. Its prevalence in the general population is approximately 2.5% (range: 1.6% to 10.0%). It is more common in men than in women.

METHODS

This review is based on pertinent publications retrieved by a selective search in PubMed.

RESULTS

MeS is the final common pathway of a wide variety of diseases; its pathogenesis is not fully understood. It often remains clinically silent for decades and is usually diagnosed as an incidental finding or in a late stage. MeS with or without atherosclerosis is the most common histologic finding after limb amputation. MeS of the below-the-knee arteries is a major risk factor for chronic critical leg ischemia (OR:13.25, 95% confidence interval: [1.69; 104.16]) and amputation (RR 2.27, [1.89; 2.74]). Patients with peripheral arterial occlusive disease and marked calcification have a much higher risk of amputation (OR 2.88, [1.18; 12.72]) and a higher mortality (OR 5.16, [1.13; 21.61]). MeS is a risk factor for the failure of endovascular treatment of the pedal arteries (OR 4.0, [1.1; 16.6]). The more marked the calcification, the higher the risk of major amputation (HR 10.6 [1.4; 80.7] to HR 15.5 [2.0; 119]). Patients with vascular calcifications have been found to have lower patency rates and higher treatment failure rates two years after open surgical revascularization of the below-the-knee arteries. No pharmacotherapy for MeS is available to date.

CONCLUSION

MeS is an important risk factor for chronic critical lower limb ischemia, amputation, morbidity, and complications, particularly after endovascular and surgical procedures.

Vitamin K supplementation and vascular calcification: a systematic review and meta-analysis of randomized controlled trials

Background

Vascular calcification (VC) is a complex process that has been linked to conditions including cardiovascular diseases and chronic kidney disease. There is an ongoing debate about whether vitamin K (VK) can effectively prevent VC. To assess the efficiency and safety of VK supplementation in the therapies of VC, we performed a systematic review and meta-analysis of recent studies.

Methods

We searched major databases, including PubMed, the Cochrane Library, Embase databases, and Web of Science up until August 2022. 14 randomized controlled trials (RCTs) describing the outcomes of treatment for VK supplementation with VC have been included out of 332 studies. The results were reported in the change of coronary artery calcification (CAC) scores, other artery and valve calcification, vascular stiffness, and dephospho-uncarboxylated matrix Gla protein (dp-ucMGP). The reports of severe adverse events were recorded and analyzed.

Results

We reviewed 14 RCTs, comprising a total of 1,533 patients. Our analysis revealed that VK supplementation has a significant effect on CAC scores, slowing down the progression of CAC [I² = 34%, MD= -17.37, 95% CI (-34.18, -0.56), p = 0.04]. The study found that VK supplementation had a significant impact on dp-ucMGP levels, as compared to the control group, where those receiving VK supplementation had lower values [I² = 71%, MD = -243.31, 95% CI (-366.08, -120.53), p = 0.0001]. Additionally, there was no significant difference in the adverse events between the groups [I² = 31%, RR = 0.92, 95% CI (-0.79,1.07), p = 0.29].

Conclusion

VK may have therapeutic potential for alleviating VC, especially CAC. However, more rigorously designed RCTs are required to verify the benefits and efficacy of VK therapy in VC.

Insights into Regulating Mechanism of Mutagenesis Strains of Elizabethkingia meningoseptica sp. F2 by Omics Analysis

Vitamin K₂ plays an important role in electron transport, blood coagulation, and calcium homeostasis, and researchers have been trying to use microbes to produce it. Although our previous studies have shown that gradient radiation, breeding, and culture acclimation can improve vitamin K₂ production in Elizabethkingia meningoseptica, the mechanism is still unclear. This study is the first which performs genome sequencing of E. meningoseptica sp. F2 as a basis for subsequent experiments and further comparative analyses with other strains. Comparative metabolic pathway analysis of E. meningoseptica sp. F2, E. coli, Bacillus subtilis, and other vitamin K₂ product strains revealed that the mevalonate pathway of E. meningoseptica sp. F2 is different in bacteria at the system level. The expressions of menA, menD, menH, and menI in the menaquinone pathway and idi, hmgR, and ggpps in the mevalonate pathway were higher than those in the original strain. A total of 67 differentially expressed proteins involved in the oxidative phosphorylation metabolic pathway and citric acid cycle (TCA cycle) were identified. Our results reveal that combined gradient radiation breeding and culture acclimation can promote vitamin K₂ accumulation probably by regulating the vitamin K₂ pathway, oxidative phosphorylation metabolism pathway, and the citrate cycle (TCA cycle).

The biological responses of vitamin K2: A comprehensive review

Vitamin K1 (VitK1) and Vitamin K2 (VitK2), two important naturally occurring micronutrients in the VitK family, found, respectively, in green leafy plants and algae (VitK1) and animal and fermented foods (VitK2). The present review explores the multiple biological functions of VitK2 from recently published in vitro and in vivo studies, including promotion of osteogenesis, prevention of calcification, relief of menopausal symptoms, enhancement of mitochondrial energy release, hepato- and neuro-protective effects, and possible use in treatment of coronavirus disease. The mechanisms of action associated with these biological effects are also explored. Overall, the findings presented here suggest that VitK, especially VitK2, is an important nutrient family for the normal functioning of human health. It acts on almost all major body systems and directly or indirectly participates in and regulates hundreds of physiological or pathological processes. However, as biological and clinical data are still inconsistent and conflicting, more in-depth investigations are warranted to elucidate its potential as a therapeutic strategy to prevent and treat a range of disease conditions.

Fat-soluble vitamins: updated review of their role and orchestration in human nutrition throughout life cycle with sex differences

Age and Gender are vital determinants for the micronutrient demands of normal indviduals. Among these micronutrients are vitamins that are required in small amounts for optimum metabolism, homeostasis, and a healthy lifestyle, acting as coenzymes in several biochemical reactions. The majority of previous studies have examined such issues that relates to a specific vitamin or life stage, with the majority merely reporting the effect of either excess or deficiency. Vitamins are classified into water-soluble and fat-soluble components. The fat-soluble vitamins include vitamins (A, D, E, and K). Fat-soluble vitamins were found to have an indisputable role in an array of physiological processes such as immune regulation, vision, bone and mental health. Nonetheless, the fat-soluble vitamins are now considered a prophylactic measurement for a multitude of diseases such as autism, rickets disease, gestational diabetes, and asthma. Herein, in this review, a deep insight into the orchestration of the four different fat-soluble vitamins requirements is presented for the first time across the human life cycle beginning from fertility, pregnancy, adulthood, and senility with an extensive assessment ofthe interactions among them and their underlying mechanistic actions. The influence of sex for each vitamin is also presented at each life stage to highlight the different daily requirements and effects.

Long-Duration Space Travel Support Must Consider Wider Influences to Conserve Microbiota Composition and Function

The microbiota is important for immune modulation, nutrient acquisition, vitamin production, and other aspects for long-term human health. Isolated model organisms can lose microbial diversity over time and humans are likely the same. Decreasing microbial diversity and the subsequent loss of function may accelerate disease progression on Earth, and to an even greater degree in space. For this reason, maintaining a healthy microbiome during spaceflight has recently garnered consideration. Diet, lifestyle, and consumption of beneficial microbes can shape the microbiota, but the replenishment we attain from environmental exposure to microbes is important too. Probiotics, prebiotics, fermented foods, fecal microbiota transplantation (FMT), and other methods of microbiota modulation currently available may be of benefit for shorter trips, but may not be viable options to overcome the unique challenges faced in long-term space travel. Novel fermented food products with particular impact on gut health, immune modulation, and other space-targeted health outcomes are worthy of exploration. Further consideration of potential microbial replenishment to humans, including from environmental sources to maintain a healthy microbiome, may also be required.

Ponicidin Treatment Improved the Cell Proliferation, Differentiation, and Calcium Mineralization on the Osteoblast-Like MG-63 Cells

Osteoporosis is a general bone-related ailment characterized by reduced bone density and quality, elevated bone fragility, and fractures. It was reported that both aged men and women has an increased risks of osteoporosis. The current research work focused to unveil the beneficial roles of ponicidin treatment in the proliferation and calcium deposition on the osteoblast-like MG-63 cells. The effect of 5 and 10 µg/ml of ponicidin on the cell proliferation was assessed. The viability of ponicidin-supplemented MG-63 cells was inspected by MTT test. The contents of osteocalcin, collagen, and ALP activity in the ponicidin administered cells were assessed by kits. The level of calcium mineralization was examined by ARS staining technique. The ponicidin treatment remarkably improved the proliferation of MG-63 cells. The ponicidin did not affect the MG-63 cells viability but promoted its viability 24- and 48-h treatment. The contents of osteocalcin, collagen, and ALP activity in the 5 and 10 µg/ml of ponicidin-supplemented MG-63 cells were found increased than the control cells. The ponicidin also increased the level of calcium deposition in MG-63 cells, which is assessed by ARS staining. In conclusion, it was clear that ponicidin improved the proliferation and calcium mineralization in a MG-63 cells. Therefore, it was clear that ponicidin has helpful roles on the new bone development as a hopeful therapeutic candidate to treat the bone-related disease like osteoporosis.

The Role of Vitamin K in CKD-MBD

PURPOSE OF REVIEW

We describe the mechanism of action of vitamin K, and its implication in cardiovascular disease, bone fractures, and inflammation to underline its protective role, especially in chronic kidney disease (CKD).

RECENT FINDINGS

Vitamin K acts as a coenzyme of y-glutamyl carboxylase, transforming undercarboxylated in carboxylated vitamin K-dependent proteins. Furthermore, through the binding of the nuclear steroid and xenobiotic receptor, it activates the expression of genes that encode proteins involved in the maintenance of bone quality and bone remodeling. There are three main types of K vitamers: phylloquinone, menaquinones, and menadione. CKD patients, for several conditions typical of the disease, are characterized by lower levels of vitamin K than the general populations, with a resulting higher prevalence of bone fractures, vascular calcifications, and mortality. Therefore, the definition of vitamin K dosage is an important issue, potentially leading to reduced bone fractures and improved vascular calcifications in the general population and CKD patients.

Effects of Vitamin D and K on Interleukin-6 in COVID-19

Background

Pathology during COVID-19 infection arises partly from an excessive inflammatory response with a key role for interleukin (IL)-6. Both vitamin D and K have been proposed as potential modulators of this process.

Methods

We assessed vitamin D and K status by measuring circulating 25-hydroxyvitamin D (25(OH)D) and desphospho-uncarboxylated Matrix Gla-Protein (dp-ucMGP), respectively in 135 hospitalized COVID-19 patients in relation to inflammatory response, elastic fiber degradation and clinical outcomes.

Results

Comparing good and poor disease outcomes of COVID-19 patients, vitamin 25(OH)D levels were not significantly different. IL-6 levels, however, were significantly higher in patients with poor outcome, compared to patients with good outcome (30.3 vs. 153.0 pg/mL; p < 0.0001). Dp-ucMGP levels as biomarker of extrahepatic vitamin K status was associated with IL-6 levels (r = 0.35; p < 0.0001). In contrast, 25(OH)D levels were only borderline statistically significant correlated with IL-6 (r = −0.14; p <0.050). A significant association was also found between IL-6 and elastic fiber degradation. Contrary to vitamin K status, 25(OH)D did not correlate with elastic fiber degradation.

Conclusions

Dp-ucMGP associates with IL-6 as a central component of the destructive inflammatory processes in COVID-19. An intervention trial may provide insight whether vitamin K administration, either or not in combination with vitamin D, improves clinical outcome of COVID-19.

The Role of GRP and MGP in the Development of Non-Hemorrhagic VKCFD1 Phenotypes

Vitamin K dependent coagulation factor deficiency type 1 (VKCFD1) is a rare hereditary bleeding disorder caused by mutations in γ-Glutamyl carboxylase (GGCX) gene. The GGCX enzyme catalyzes the γ-carboxylation of 15 different vitamin K dependent (VKD) proteins, which have function in blood coagulation, calcification, and cell signaling. Therefore, in addition to bleedings, some VKCFD1 patients develop diverse non-hemorrhagic phenotypes such as skin hyper-laxity, skeletal dysmorphologies, and/or cardiac defects. Recent studies showed that GGCX mutations differentially effect γ-carboxylation of VKD proteins, where clotting factors are sufficiently γ-carboxylated, but not certain non-hemostatic VKD proteins. This could be one reason for the development of diverse phenotypes. The major manifestation of non-hemorrhagic phenotypes in VKCFD1 patients are mineralization defects. Therefore, the mechanism of regulation of calcification by specific VKD proteins as matrix Gla protein (MGP) and Gla-rich protein (GRP) in physiological and pathological conditions is of high interest. This will also help to understand the patho-mechanism of VKCFD1 phenotypes and to deduce new treatment strategies. In the present review article, we have summarized the recent findings on the function of GRP and MGP and how these proteins influence the development of non-hemorrhagic phenotypes in VKCFD1 patients.

Biological Role of Vitamin K-With Particular Emphasis on Cardiovascular and Renal Aspects

Vitamin K (VK) plays many important functions in the body. The most important of them include the contribution in calcium homeostasis and anticoagulation. Vascular calcification (VC) is one of the most important mechanisms of renal pathology. The most potent inhibitor of this process-matrix Gla protein (MGP) is VK-dependent. Chronic kidney disease (CKD) patients, both non-dialysed and hemodialysed, often have VK deficiency. Elevated uncarboxylated matrix Gla protein (ucMGP) levels indirectly reflected VK deficiency and are associated with a higher risk of cardiovascular events in these patients. It has been suggested that VK intake may reduce the VC and related cardiovascular risk. Vitamin K intake has been suggested to reduce VC and the associated cardiovascular risk. The role and possibility of VK supplementation as well as the impact of anticoagulation therapy on VK deficiency in CKD patients is discussed.

The First Evaluation of Serum Levels of MGP, Gas6 and EGFR after First Dose of Chemotherapy in Lung Cancer

Simple Summary

Serum levels of MGP, Gas6, vitamin K₁, and EGFR were not significantly changed in response to the first cycle of chemotherapy. We found a strong correlation between MGP and VitK₁ serum values, and a moderate negative correlation between VitK₁ and EGFR in pre-treatment patients. The post-treatment value of EGFR is a strong independent factor that correlates positively with the Gas6 post-treatment values.

Abstract

Background: Vitamin K-dependent proteins (VKDPs) and the epidermal growth factor receptor (EGFR) are involved in lung cancer progression. Therefore, we aimed to study the serum concentration of Matrix Gla protein (MGP), Growth Arrest-specific 6 (Gas6), and EGFR before and after the first cycle of chemotherapy and to investigate how MGP, Gas6, and EGFR are modified after one cycle of chemotherapy. Methods: We performed an observational study on twenty patients diagnosed with lung cancer, by assessing the serum concentration of vitaminK₁ (VitK₁), MGP, Gas6, and EGFR using the ELISA technique before and after three weeks of the first cycle of chemotherapy. Patients were evaluated using RECIST 1.1 criteria. Results: Serum levels of MGP, Gas6, EGFR, and VK₁ before and after treatment were not changed significantly. Regarding the pre-treatment correlation of the MGP values, we found a strong positive relationship between MGP and VK₁ pre-treatment values (r = 0.821, 95%CI 0.523; 0.954, p < 0.001). Furthermore, there was a moderately negative correlation between VK₁ and EGFR pre-treatment values, with the relationship between them being marginally significant (r = −0.430, 95%CI −0.772; 0.001, p = 0.058). Post-treatment, we found a strong positive relationship between MGP and VK₁ post-treatment values (r = 0.758, 95%CI 0.436; 0.900, p < 0.001). We also found a moderate positive relationship between Gas6 and EGFR post-treatment values, but the correlation was only marginally significant (r = 0.442, p = 0.051).

Effective management of atherosclerosis progress and hyperlipidemia with nattokinase: A clinical study with 1,062 participants

Nattokinase (NK), known as a potent fibrinolytic and antithrombotic agent, has been shown to have antiatherosclerotic and lipid-lowering effects. However, data on human clinical studies are limited. In this clinical study involving 1,062 participants, our objective was to examine the efficacy of NK in atherosclerosis and hyperlipidemia and safety at the dose of 10,800 FU/day after 12 months of oral administration. Various factors, including lower doses that influence NK pharmacological actions, were also investigated. We found that NK at a dose of 10,800 FU/day effectively managed the progression of atherosclerosis and hyperlipidemia with a significant improvement in the lipid profile. A significant reduction in the thickness of the carotid artery intima-media and the size of the carotid plaque was observed. The improvement rates ranged from 66.5 to 95.4%. NK was found to be ineffective in lowering lipids and suppressing atherosclerosis progression at a dose of 3,600 FU/day. The lipid-lowering effect of NK was more prominent in subjects who smoked, drank alcohol, and subjects with higher BMI. Regular exercise further improved the effects of NK. Co-administration of vitamin K2 and aspirin with NK produced a synergetic effect. No noticeable adverse effects associated with the use of NK were recorded. In conclusion, our data demonstrate that atherosclerosis progression and hyperlipidemia can be effectively managed with NK at a dose of 10,800 FU/day. The lower dose of 3,600 FU per day is ineffective. The dose of 10,800 FU/day is safe and well tolerated. Some lifestyle factors and the coadministration of vitamin K2 and aspirin lead to improved outcomes in the use of NK. Our findings provide clinical evidence on the effective dose of NK in the management of cardiovascular disease and challenge the recommended dose of 2,000 FU per day.

Simultaneous Determination of Vitamins D3 (Calcitriol, Cholecalciferol) and K2 (Menaquinone-4 and Menaquinone-7) in Dietary Supplements by UHPLC

The content and composition of dietary supplements is of great interest due to their increasing consumption and variety of available brand offered in the market. Accurate determination of vitamins is important for the improvement of dietary supplement quality and nutrition assessments. In this regard, the simultaneous determination of vitamin D3 (calcitriol-CT and cholecalciferol-CHL) and K2 (menaquinone-4-MK-4 and menaquinone-7-MK-7) in dietary supplements was developed by using ultra-high-pressure liquid chromatography (UHPLC). The overall runtime per sample was above 35 min, with the retention times of 2.40, 6.59, 7.06, and 32.6 min for vitamin D3 (CT and CHL) and vitamin K2 (MK-4 and MK-7), respectively. The limits of detection and limits of quantification for the target nutritional compounds ranged between 0.04-0.05 µg/mL, respectively. The validation results indicated that the method had reasonable linearity (R² ≥ 0.9990), good recovery (>82%), satisfactory intra-day precision (≤1.9%) and inter-day precision (≤3.5%), and high selectivity and specificity. The validated UHPLC method was demonstrated to be precise, accurate, and robust for the simultaneous determination of vitamins D3 (CT and CHL) and K2 (MK-4 and MK-7) in dietary supplements.

Biomolecules Orchestrating Cardiovascular Calcification

Vascular calcification, once considered a degenerative, end-stage, and inevitable condition, is now recognized as a complex process regulated in a manner similar to skeletal bone at the molecular and cellular levels. Since the initial discovery of bone morphogenetic protein in calcified human atherosclerotic lesions, decades of research have now led to the recognition that the regulatory mechanisms and the biomolecules that control cardiovascular calcification overlap with those controlling skeletal mineralization. In this review, we focus on key biomolecules driving the ectopic calcification in the circulation and their regulation by metabolic, hormonal, and inflammatory stimuli. Although calcium deposits in the vessel wall introduce rupture stress at their edges facing applied tensile stress, they simultaneously reduce rupture stress at the orthogonal edges, leaving the net risk of plaque rupture and consequent cardiac events depending on local material strength. A clinically important consequence of the shared mechanisms between the vascular and bone tissues is that therapeutic agents designed to inhibit vascular calcification may adversely affect skeletal mineralization and vice versa. Thus, it is essential to consider both systems when developing therapeutic strategies.

Synthetic vitamin K analogs inhibit inflammation by targeting the NLRP3 inflammasome

Vitamin K refers to a group of structurally similar vitamins that are essential for proper blood coagulation, as well as bone and cardiovascular health. Previous studies have indicated that vitamin K may also have anti-inflammatory properties, although the underlying mechanisms of its anti-inflammatory effects remain unclear. The NLRP3 inflammasome is a multiprotein complex, and its activation leads to IL-1β and IL-18 secretion and contributes to the pathogenesis of various human inflammatory diseases. Here, we show that synthetic vitamins K3 and K4 are selective, potent inhibitors of the NLRP3 inflammasome and specifically block the interaction between NLRP3 and ASC, thereby inhibiting NLRP3 inflammasome assembly. Moreover, we show that treatment with vitamin K3 or K4 attenuates the severity of inflammation in a mouse model of peritonitis. Our results demonstrate that vitamins K3 and K4 exert their anti-inflammatory effects by inhibiting NLRP3 inflammasome activation and indicate that vitamin K supplementation may be a treatment option for NLRP3-associated inflammatory diseases.

Recognized and Potentially New Biomarkers-Their Role in Diagnosis and Prognosis of Cardiovascular Disease

Atherosclerosis and its consequences are the leading cause of mortality in the world. For this reason, we have reviewed atherosclerosis biomarkers and selected the most promising ones for review. We focused mainly on biomarkers related to inflammation and oxidative stress, such as the highly sensitive C-reactive protein (hs-CRP), interleukin 6 (IL-6), and lipoprotein-associated phospholipase A2 (Lp-PLA2). The microRNA (miRNA) and the usefulness of the bone mineralization, glucose, and lipid metabolism marker osteocalcin (OC) were also reviewed. The last biomarker we considered was angiogenin (ANG). Our review shows that due to the multifactorial nature of atherosclerosis, no single marker is known so far, the determination of which would unambiguously assess the severity of atherosclerosis and help without any doubt in the prognosis of cardiovascular risk.

Evolution of Matrix Gla and Bone Gla Protein Genes in Jawed Vertebrates

Matrix Gla protein (Mgp) and bone Gla protein (Bgp) are vitamin-K dependent proteins that bind calcium in their γ-carboxylated versions in mammals. They are recognized as positive (Bgp) or negative (Mgp and Bgp) regulators of biomineralization in a number of tissues, including skeletal tissues of bony vertebrates. The Mgp/Bgp gene family is poorly known in cartilaginous fishes, which precludes the understanding of the evolution of the biomineralization toolkit at the emergence of jawed vertebrates. Here we took advantage of recently released genomic and transcriptomic data in cartilaginous fishes and described the genomic loci and gene expression patterns of the Mgp/Bgp gene family. We identified three genes, Mgp1, Mgp2, and Bgp, in cartilaginous fishes instead of the single previously reported Mgp gene. We describe their genomic loci, resulting in a dynamic evolutionary scenario for this gene family including several events of local (tandem) duplications, but also of translocation events, along jawed vertebrate evolution. We describe the expression patterns of Mgp1, Mgp2, and Bgp in embryonic stages covering organogenesis in the small-spotted catshark Scyliorhinus canicula and present a comparative analysis with Mgp/Bgp family members previously described in bony vertebrates, highlighting ancestral features such as early embryonic, soft tissues, and neuronal expressions, but also derived features of cartilaginous fishes such as expression in fin supporting fibers. Our results support an ancestral function of Mgp in skeletal mineralization and a later derived function of Bgp in skeletal development that may be related to the divergence of bony vertebrates.

Role of emerging vitamin K‑dependent proteins: Growth arrest‑specific protein 6, Gla‑rich protein and periostin (Review)

Vitamin K‑dependent proteins (VKDPs) are a group of proteins that need vitamin K to conduct carboxylation. Thus far, scholars have identified a total of 17 VKDPs in the human body. In this review, we summarize three important emerging VKDPs: Growth arrest‑specific protein 6 (Gas 6), Gla‑rich protein (GRP) and periostin in terms of their functions in physiological and pathological conditions. As examples, carboxylated Gas 6 and GRP effectively protect blood vessels from calcification, Gas 6 protects from acute kidney injury and is involved in chronic kidney disease, GRP contributes to bone homeostasis and delays the progression of osteoarthritis, and periostin is involved in all phases of fracture healing and assists myocardial regeneration in the early stages of myocardial infarction. However, periostin participates in the progression of cardiac fibrosis, idiopathic pulmonary fibrosis and airway remodeling of asthma. In addition, we discuss the relationship between vitamin K, VKDPs and cancer, and particularly the carboxylation state of VKDPs in cancer.

The Medical Benefits of Vitamin K2 on Calcium-Related Disorders

BACKGROUND

Due to the potentially crucial role of vitamin K2 in calcium metabolism, a deficit can disrupt many mechanisms, resulting in an array of different issues, such as broken bones, stiff arteries and poor fertility. Although there has been existing research, the potential of vitamin K2 as a treatment for conditions including cerebral palsy, parathyroid disease, heart disease and gastrointestinal disease is unknown. This review discusses the biochemistry of vitamin K and the metabolism of calcium, followed by an analysis of the current literature available on vitamin K2 and its prospects.

METHODS

Using public libraries including PubMed and Wiley, we searched for existing research on the metabolism and use of vitamin K2 that has been conducted in the preceding two decades.

RESULTS

Data indicated that vitamin K2 had a positive impact on osteoporosis, cardiovascular disease, parathyroid disorders, cerebral palsy and sperm motility.

CONCLUSION

Due to the existence of confounding variables and limitations in the quality and volume of research conducted, further investigation must be done to see whether the beneficial effects seen are reproducible and must assess the viability of vitamin K2 as treatment in isolation for these conditions.

Gut Microbiota and the Quality of Oral Anticoagulation in Vitamin K Antagonists Users: A Review of Potential Implications

The efficacy and safety of vitamin K antagonists (VKAs) as oral anticoagulants (OACs) depend on the quality of anticoagulation control, as reflected by the mean time in therapeutic range (TTR). Several factors may be involved in poor TTR such as comorbidities, high inter-individual variability, interacting drugs, and non-adherence. Recent studies suggest that gut microbiota (GM) plays an important role in the pathogenesis of cardiovascular diseases, but the effect of the GM on anticoagulation control with VKAs is unknown. In the present review article, we propose different mechanisms by which the GM could have an impact on the quality of anticoagulation control in patients taking VKA therapy. We suggest that the potential effects of GM may be mediated first, by an indirect effect of metabolites produced by GM in the availability of VKAs drugs; second, by an effect of vitamin K-producing bacteria; and finally, by the structural modification of the molecules of VKAs. Future research will help confirm these hypotheses and may suggest profiles of bacterial signatures or microbial metabolites, to be used as biomarkers to predict the quality of anticoagulation. This could lead to the design of intervention strategies modulating gut microbiota, for example, by using probiotics.

Vitamin K2 Suppresses Proliferation and Inflammatory Cytokine Production in Mitogen-Activated Lymphocytes of Atopic Dermatitis Patients through the Inhibition of Mitogen-Activated Protein Kinases

Vitamin K2 is suggested to have a suppressive effect on the peripheral blood mononuclear cells (PBMCs) of pediatric atopic dermatitis patients. We examined the molecular targets of vitamin K2 to suppress proliferation and cytokine production in T-cell mitogen-activated PBMCs of atopic dermatitis patients from the viewpoint of mitogen-activated protein kinase signaling molecules. The study population included 16 pediatric vitamin K2 patients and 21 healthy subjects. The effect of vitamin K2 on concanavalin A-activated PBMC proliferation was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and cell counting assays. T-helper (Th)1/Th2/Th17 cytokine profiles in plasma and PBMC-culture supernatants were analyzed by a cytometric beads array assay. Mitogen-activated protein kinase signaling molecules in concanavalin A-activated PBMCs were examined by enzyme-linked immunosorbent assay (ELISA) assays. At 10-100 µM, vitamin K2 significantly suppressed the proliferation of mitogen-activated PBMCs derived from atopic dermatitis patients and healthy subjects (p < 0.05). The interleukin (IL)-10 concentrations in plasma and the PBMC culture supernatants of atopic dermatitis patients were significantly higher than those of healthy subjects (p < 0.05). The IL-2 concentrations in the culture supernatants of atopic dermatitis PBMCs were significantly lower than those of healthy PBMCs (p < 0.05). Vitamin K2 significantly inhibited the IL-17A, IL-10, and tumor necrosis factor α (TNF-α) production (p < 0.05), and increased the IL-2 production (p < 0.01) in the culture supernatant of atopic dermatitis PBMCs. At 10-100 µM, vitamin K2 markedly decreased the of Mek1, extracellular signal-regulated kinases (ERK)1/2 mitogen-activated protein kinase, and SAPK/c-Jun N-terminal kinase (JNK) expression in atopic dermatitis PBMCs (p < 0.05). Vitamin K2 is suggested to attenuate activated T-cell immunity in atopic dermatitis patients through the inhibition of mitogen-activated protein kinase-Mek1-ERK1/2 and SAPK/JNK signaling pathways.

Influence of Vitamin K on Bone Mineral Density and Osteoporosis

Vitamin K (VK) has an established biological function in blood coagulation and hemostasis and maintains general health and bone wellbeing. VK supplements have been promoted to treat and prevent many diseases, particularly for decreasing fracture risk in osteoporosis, a chronic condition described by weak bone tissue, and a high fracture risk following minor trauma. It affects older people from different races and ethnicity, mainly postmenopausal women. Many kinds of research emphasize the role of VK in improving bone health and preventing osteoporotic bone fracture, but the findings are mostly inconclusive. In this literature review, PubMed and Google Scholar databases were used as the primary sources to select the relevant studies and review the association between VK and bone health and also, to explore the impact of VK supplementation in osteoporosis management. A majority of studies reported that VK has an essential role in promoting bone health. Although some studies revealed that VK might increase bone mineral density and reduce fracture risk in people with osteoporosis, VK supplements' potential benefits were not sufficiently supported. Thus, more clinical studies are needed to determine the positive effects of VK supplementation in osteoporosis prevention and treatment.

Effects of Minor Compounds of Edible Oils on Human Health

Background:

Oils and fats are the densest sources of food energy among food groups. Vegetable oils are constituted predominantly of triglycerides. Due to the importance of edible oils in nutrition, food industry and human health, great attention has been paid to them in recent years. Some minor bioactive constituents in oils include phospholipids, tocols, sterols, carotenoid, chlorophyll, phenols, phylokynon and terpenes.

Objective:

The aim of the present study was to examine beneficial effects of minor compounds in edible oils on human health. Results: Minor compounds of edible oils that we use daily can produce remarkable results in the prevention and treatment of various diseases like diabetes, inflammation, hypertension, cancer, allergy and central nervous system disorders due to their antimicrobial, anti-cancer, anti-viral, anti-oxidative, anti-inflammation, anti-mutagenic, hypolipidemic, and hypoglycemic properties, among others.

Conclusion:

The results of this study showed that the presence of beneficial minor compounds in oils could have significant impact on the prevention and treatment of various diseases. Therefore, the type of consumed oil can play an important role in human health.

Vitamin K in Vertebrates' Reproduction: Further Puzzling Pieces of Evidence from Teleost Fish Species

Vitamin K (VK) is a fat-soluble vitamin that vertebrates have to acquire from the diet, since they are not able to de novo synthesize it. VK has been historically known to be required for the control of blood coagulation, and more recently, bone development and homeostasis. Our understanding of the VK metabolism and the VK-related molecular pathways has been also increased, and the two main VK-related pathways-the pregnane X receptor (PXR) transactivation and the co-factor role on the γ-glutamyl carboxylation of the VK dependent proteins-have been thoroughly investigated during the last decades. Although several studies evidenced how VK may have a broader VK biological function than previously thought, including the reproduction, little is known about the specific molecular pathways. In vertebrates, sex differentiation and gametogenesis are tightly regulated processes through a highly complex molecular, cellular and tissue crosstalk. Here, VK metabolism and related pathways, as well as how gametogenesis might be impacted by VK nutritional status, will be reviewed. Critical knowledge gaps and future perspectives on how the different VK-related pathways come into play on vertebrate's reproduction will be identified and proposed. The present review will pave the research progress to warrant a successful reproductive status through VK nutritional interventions as well as towards the establishment of reliable biomarkers for determining proper nutritional VK status in vertebrates.

Vitamin K2 Modulates Vitamin D-Induced Mechanical Properties of Human 3D Bone Spheroids In Vitro

Rotational culture promotes primary human osteoblasts (hOBs) to form three-dimensional (3D) multicellular spheroids with bone tissue-like structure without any scaffolding material. Cell-based bone models enable us to investigate the effect of different agents on the mechanical strength of bone. Given that low dietary intake of both vitamin D and K is negatively associated with fracture risk, we aimed to assess the effect of these vitamins in this system. Osteospheres of hOBs were generated with menaquinone-4 (MK-4; 10μM) and 25-hydroxyvitamin D₃ [25(OH)D₃; 0.01μM], alone and in combination, or without vitamins. The mechanical properties were tested by nanoindentation using a flat-punch compression method, and the mineralized extracellular bone matrix was characterized by microscopy. The in vitro response of hOBs to MK-4 and 25(OH)D₃ was further evaluated in two-dimensional (2D) cultures and in the 3D bone constructs applying gene expression analysis and multiplex immunoassays. Mechanical testing revealed that 25(OH)D₃ induced a stiffer and MK-4 a softer or more flexible osteosphere compared with control. Combined vitamin conditions induced the same flexibility as MK-4 alone. Enhanced levels of periostin (p < 0.001) and altered distribution of collagen type I (COL-1) were found in osteospheres supplemented with MK-4. In contrast, 25(OH)D₃ reduced COL-1, both at the mRNA and protein levels, increased alkaline phosphatase, and stimulated mineral deposition in the osteospheres. With the two vitamins in combination, enhanced gene expression of periostin and COL-1 was seen, as well as extended osteoid formation into the central region and increased mineral deposition all over the area. Moreover, we observed enhanced levels of osteocalcin in 2D and osteopontin in 3D cultures exposed to 25(OH)D₃ alone and combined with MK-4. In conclusion, the two vitamins seem to affect bone mechanical properties differently: vitamin D enhancing stiffness and K2 conveying flexibility to bone. These effects may translate to increased fracture resistance in vivo. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

The Bone Extracellular Matrix in Bone Formation and Regeneration

Bone regeneration repairs bone tissue lost due to trauma, fractures, and tumors, or absent due to congenital disorders. The extracellular matrix (ECM) is an intricate dynamic bio-environment with precisely regulated mechanical and biochemical properties. In bone, ECMs are involved in regulating cell adhesion, proliferation, and responses to growth factors, differentiation, and ultimately, the functional characteristics of the mature bone. Bone ECM can induce the production of new bone by osteoblast-lineage cells, such as MSCs, osteoblasts, and osteocytes and the absorption of bone by osteoclasts. With the rapid development of bone regenerative medicine, the osteoinductive, osteoconductive, and osteogenic potential of ECM-based scaffolds has attracted increasing attention. ECM-based scaffolds for bone tissue engineering can be divided into two types, that is, ECM-modified biomaterial scaffold and decellularized ECM scaffold. Tissue engineering strategies that utilize the functional ECM are superior at guiding the formation of specific tissues at the implantation site. In this review, we provide an overview of the function of various types of bone ECMs in bone tissue and their regulation roles in the behaviors of osteoblast-lineage cells and osteoclasts. We also summarize the application of bone ECM in bone repair and regeneration. A better understanding of the role of bone ECM in guiding cellular behavior and tissue function is essential for its future applications in bone repair and regenerative medicine.

The Role of Vitamin D in Modulating Mesenchymal Stem Cells and Endothelial Progenitor Cells for Vascular Calcification

Vascular calcification, which involves the deposition of calcifying particles within the arterial wall, is mediated by atherosclerosis, vascular smooth muscle cell osteoblastic changes, adventitial mesenchymal stem cell osteoblastic differentiation, and insufficiency of the calcification inhibitors. Recent observations implied a role for mesenchymal stem cells and endothelial progenitor cells in vascular calcification. Mesenchymal stem cells reside in the bone marrow and the adventitial layer of arteries. Endothelial progenitor cells that originate from the bone marrow are an important mechanism for repairing injured endothelial cells. Mesenchymal stem cells may differentiate osteogenically by inflammation or by specific stimuli, which can activate calcification. However, the bioactive substances secreted from mesenchymal stem cells have been shown to mitigate vascular calcification by suppressing inflammation, bone morphogenetic protein 2, and the Wingless-INT signal. Vitamin D deficiency may contribute to vascular calcification. Vitamin D supplement has been used to modulate the osteoblastic differentiation of mesenchymal stem cells and to lessen vascular injury by stimulating adhesion and migration of endothelial progenitor cells. This narrative review clarifies the role of mesenchymal stem cells and the possible role of vitamin D in the mechanisms of vascular calcification.

Controlled Delivery of Curcumin and Vitamin K2 from Hydroxyapatite-Coated Titanium Implant for Enhanced in Vitro Chemoprevention, Osteogenesis, and in Vivo Osseointegration

Successful repair of critical-sized tumor-resection defects, especially in load-bearing bones, still remains a major challenge in clinical orthopedics. Titanium (Ti) implants have been increasingly used in the past few decades because of titanium's suitable mechanical properties and biocompatibility; however, it shows insufficient integration with the surrounding bone. In this study, the plasma spray technique is utilized to form homogeneous hydroxyapatite (HA) coating on the surface of the Ti implant to enhance osseointegration at the tissue-implant interface. These coated implants are loaded with curcumin and vitamin K2 to introduce chemopreventive and osteogenesis ability via controlled release of these biomolecules. The synergistic effect of these two biomolecules showed enhanced in vitro osteoblast (hFOB) cell attachment and proliferation for 11 days. Moreover, these biomolecules showed lower in vitro osteosarcoma (MG-63) cell proliferation after 3, 7, and 11 days. An in vivo study was carried out to evaluate the bone bonded zone in a rat distal femur model at an early wound healing stage of 5 days. Modified Masson Goldner staining of the tissue-implant section showed improved contact between tissue and implant in dual drug-loaded HA-coated Ti implants compared to control implants. This work presents a successful fabrication of a mechanically competent functional Ti implant with the advantages of enhanced in vitro osteoblast proliferation, osteosarcoma inhibition, and in vivo osseointegration, indicating the potential for load-bearing bone-defect repair after tumor resection.

Engineering Lactococcus lactis for Increased Vitamin K2 Production

Cheese produced with Lactococcus lactis is the main source of vitamin K2 in the Western diet. Subclinical vitamin K2 deficiency is common, calling for foods with enhanced vitamin K2 content. In this study we describe analyses of vitamin K2 (menaquinone) production in the lactic acid bacterium L. lactis ssp. cremoris strain MG1363. By cloning and expression from strong promoters we have identified genes and bottlenecks in the biosynthetic pathways leading to the long-chained menaquinones, MK-8 and MK-9. Key genes of the biosynthetic menaquinone pathway were overexpressed, singly or combined, to examine how vitamin K2 production can be enhanced. We observed that the production of the long menaquinone polyprenyl side chain, rather than production of the napthoate ring (1,4-dihydroxy-2-naphtoic acid), limits total menaquinone synthesis. Overexpression of genes causing increased ring formation (menF and menA) led to overproduction of short chained MK-3, while overexpression of other key genes (mvk and llmg_0196) resulted in enhanced full-length MK-9 production. Of two putatively annotated prenyl diphosphate synthases we pinpoint llmg_0196 (preA) to be important for menaquinone production in L. lactis. The genes mvk, preA, menF, and menA were found to be important contributors to menaquinone levels as single overexpression of these genes double and more than triple the total menaquinone content in culture. Combined overexpression of mvk, preA, and menA increased menaquinone levels to a higher level than obtained individually. When the overproducing strains were applied for milk fermentations vitamin K2 content was effectively increased 3-fold compared to the wild type. The results provide a foundation for development of strains to ferment foods with increased functional value i.e., higher vitamin K2 content.

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.

Endocrine roles of vitamin K-dependent- osteocalcin in the relation between bone metabolism and metabolic disorders

Obesity and diabetes are important metabolic diseases and a major public health problem among the world, they have serious health and economic complications. Overweight and obesity are increased risk for deficiency of vitamin particularly shortage of fat soluble-vitamins. Studies reported that vitamin K supplementation reduces oxidative stress and metabolic risk biomarkers for diabetes, as well as reduces progression of insulin resistance. Vitamin K-dependent-protein osteocalcin (bone derived hormone) plays crucial roles in energy metabolism. There is a clear association between circulating vitamin k and dependent-osteocalcin concentrations with obesity and risk of Type 2 diabetes. Osteocalcin through molecular mechanisms improves insulin resistance, lipid and glucose profile, and mediate vitamin K positive effects. Insulin also signals osteocalcin to regulate bone mineralization. Normal carboxylation of vitamin K-dependent proteins/ hormones is a key step in preventing apoptosis and calcification of vascular endothelial cells. A missing relationship between bone, glucose and fat metabolism could clarify and manage many metabolic mechanisms. This review focuses on the physiological relationship between vitamin K-dependent-osteocalcin, metabolic and cardiovascular diseases through some molecular proteins and hormones including adipokines. A better understanding of the mechanism of action of osteocalcin modulated by vitamin K could help in implementing therapeutic drugs to cure metabolic diseases.

The Inhibitory Roles of Vitamin K in Progression of Vascular Calcification

Vitamin K is a fat-soluble vitamin that is indispensable for the activation of vitamin K-dependent proteins (VKDPs) and may be implicated in cardiovascular disease (CVD). Vascular calcification is intimately associated with CV events and mortality and is a chronic inflammatory process in which activated macrophages promote osteoblastic differentiation of vascular smooth muscle cells (VSMCs) through the production of proinflammatory cytokines such as IL-1β, IL-6, TNF-α, and oncostatin M (OSM) in both intimal and medial layers of arterial walls. This process may be mainly mediated through NF-κB signaling pathway. Vitamin K has been demonstrated to exert anti-inflammatory effects through antagonizing NF-κB signaling in both in vitro and in vivo studies, suggesting that vitamin K may prevent vascular calcification via anti-inflammatory mechanisms. Matrix Gla protein (MGP) is a major inhibitor of soft tissue calcification and contributes to preventing both intimal and medial vascular calcification. Vitamin K may also inhibit progression of vascular calcification by enhancing the activity of MGP through facilitating its γ-carboxylation. In support of this hypothesis, the procalcific effects of warfarin, an antagonist of vitamin K, on arterial calcification have been demonstrated in several clinical studies. Among the inactive MGP forms, dephospho-uncarboxylated MGP (dp-ucMGP) may be regarded as the most useful biomarker of not only vitamin K deficiency, but also vascular calcification and CVD. There have been several studies showing the association of circulating levels of dp-ucMGP with vitamin K intake, vascular calcification, mortality, and CVD. However, additional larger prospective studies including randomized controlled trials are necessary to confirm the beneficial effects of vitamin K supplementation on CV health.

Vitamin K as a Diet Supplement with Impact in Human Health: Current Evidence in Age-Related Diseases

Vitamin K health benefits have been recently widely shown to extend beyond blood homeostasis and implicated in chronic low-grade inflammatory diseases such as cardiovascular disease, osteoarthritis, dementia, cognitive impairment, mobility disability, and frailty. Novel and more efficient nutritional and therapeutic options are urgently needed to lower the burden and the associated health care costs of these age-related diseases. Naturally occurring vitamin K comprise the phylloquinone (vitamin K1), and a series of menaquinones broadly designated as vitamin K2 that differ in source, absorption rates, tissue distribution, bioavailability, and target activity. Although vitamin K1 and K2 sources are mainly dietary, consumer preference for diet supplements is growing, especially when derived from marine resources. The aim of this review is to update the reader regarding the specific contribution and effect of each K1 and K2 vitamers in human health, identify potential methods for its sustainable and cost-efficient production, and novel natural sources of vitamin K and formulations to improve absorption and bioavailability. This new information will contribute to foster the use of vitamin K as a health-promoting supplement, which meets the increasing consumer demand. Simultaneously, relevant information on the clinical context and direct health consequences of vitamin K deficiency focusing in aging and age-related diseases will be discussed.

Association between oral anticoagulants and osteoporosis: Real-world data mining using a multi-methodological approach

Introduction: Warfarin and direct oral anticoagulants (DOACs) have been widely used in antithrombotic therapy. Although warfarin use has been suspected to be associated with osteoporosis risk, several studies have shown otherwise. Conversely, a few reports have found an association between DOACs and osteoporosis. This study therefore clarifies the association between oral anticoagulants and osteoporosis by analyzing real-world data using different methodologies, algorithms, and databases. Methods: Real-world data from the US Food and Drug Administration Adverse Event Reporting System (FAERS; 2004-2016) and Japanese administrative claims database (2005-2017; JMDC Inc., Tokyo) were used. Reporting odds ratio (ROR) and information component (IC) were calculated through disproportionality analysis (DPA) using reports recorded in the FAERS. Sequence symmetry analysis (SSA) was employed to calculate the adjusted sequence ratio (SR) using the JMDC Claims Database. For the adjusted SR and ROR, a significant signal was detected when the lower limit of the two-sided 95% confidence interval (CI) was more than 1. For the IC, a significant signal was detected when the lower limit of the 95% CI was more than 0. Results: DPA for warfarin found significant signals for osteoporosis in ROR (1.43, 95% CI: 1.32-1.54) and IC (0.50, 95% CI: 0.39-0.61). SSA showed a significant association between warfarin use and osteoporosis or bisphosphonate use. Moreover, a significant association was observed in males and females, albeit only for warfarin. Conclusion: Multi-methodological data mining revealed that warfarin use, not DOACs, is significantly associated with osteoporosis regardless of sex difference.

Vitamin K and Bone Health: A Review on the Effects of Vitamin K Deficiency and Supplementation and the Effect of Non-Vitamin K Antagonist Oral Anticoagulants on Different Bone Parameters

Although known for its importance in the coagulation cascade, vitamin K has other functions. It is an essential vitamin for bone health, taking part in the carboxylation of many bone-related proteins, regulating genetic transcription of osteoblastic markers, and regulating bone reabsorption. Vitamin K deficiency is not uncommon, as deposits are scarce and dependent upon dietary supplementation and absorption. Vitamin K antagonist oral anticoagulants, which are prescribed to many patients, also induce vitamin K deficiency. Most studies find that low serum K1 concentrations, high levels of undercarboxylated osteocalcin (ucOC), and low dietary intake of both K1 and K2 are associated with a higher risk of fracture and lower BMD. Studies exploring the relationship between vitamin K supplementation and fracture risk also find that the risk of fracture is reduced with supplements, but high quality studies designed to evaluate fracture as its primary endpoint are needed. The reduction in risk of fracture with the use of non-vitamin K antagonist oral anticoagulants instead of warfarin is also of interest although once again, the available evidence offers disparate results. The scarce and limited evidence, including low quality studies reaching disparate conclusions, makes it impossible to extract solid conclusions on this topic, especially concerning the use of vitamin K supplements.

BONE MARKERS IN ARTHROPATHIES

Bone endures a lifelong course of construction and destruction, with bone marker (BM) molecules released during this cycle. The field of measuring BM levels in synovial fluid and peripheral blood is a cardinal part of bone research within modern clinical medicine and has developed extensively in the last years. The purpose of our work was to convey an up-to-date overview on synovial fluid and serum BMs in the most common arthropathies.

Long-chain vitamin K2 production in Lactococcus lactis is influenced by temperature, carbon source, aeration and mode of energy metabolism

Background

Vitamin K2 (menaquinone, MK-n) is a lipid-soluble vitamin that functions as a carboxylase co-factor for maturation of proteins involved in many vital physiological processes in humans. Notably, long-chain vitamin K2 is produced by bacteria, including some species and strains belonging to the group of lactic acid bacteria (LAB) that play important roles in food fermentation processes. This study was performed to gain insights into the natural long-chain vitamin K2 production capacity of LAB and the factors influencing vitamin K2 production during cultivation, providing a basis for biotechnological production of vitamin K2 and in situ fortification of this vitamin in food products.

Results

We observed that six selected Lactococcus lactis strains produced MK-5 to MK-10, with MK-8 and MK-9 as the major MK variant. Significant diversities between strains were observed in terms of specific concentrations and titres of vitamin K2. L. lactis ssp. cremoris MG1363 was selected for more detailed studies of the impact of selected carbon sources tested under different growth conditions [i.e. static fermentation (oxygen absent, heme absent); aerobic fermentation (oxygen present, heme absent) and aerobic respiration (oxygen present, heme present)] on vitamin K2 production in M17 media. Aerobic fermentation with fructose as a carbon source resulted in the highest specific concentration of vitamin K2: 3.7-fold increase compared to static fermentation with glucose, whereas aerobic respiration with trehalose resulted in the highest titre: 5.2-fold increase compared to static fermentation with glucose. When the same strain was applied to quark fermentation, we consistently observed that altered carbon source (fructose) and aerobic cultivation of the pre-culture resulted in efficient vitamin K2 fortification in the quark product.

Conclusions

With this study we demonstrate that certain LAB strains can be employed for efficient production of long-chain vitamin K2. Strain selection and optimisation of growth conditions offer a viable strategy towards natural vitamin K2 enrichment of fermented foods, and to improved biotechnological vitamin K2 production processes.

Electronic supplementary material

The online version of this article (10.1186/s12934-019-1179-9) contains supplementary material, which is available to authorized users.

Vitamin K-Dependent Matrix Gla Protein as Multifaceted Protector of Vascular and Tissue Integrity

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Adherence to Long-Term Follow-Up of Patients with Life-Threatening, Inhaled Synthetic Cannabinoids-Associated Coagulopathy in Chicago

A large-scale outbreak of life-threatening, inhaled synthetic cannabinoids (Spice/K2)-associated coagulopathy with bleeding complications was recently reported in Illinois. The causative agents were brodifacoum, difenacoum, and bromadiolone, potent, long-acting, 4-hydroxycoumarin anticoagulant rodenticides (LAAR) that were mixed with Spice/K2 products procured and then inhaled by the victims. We report on 3 poisoned patients who reside in underserved, socioeconomically disadvantaged neighborhoods of Chicago that were admitted and treated successfully at two inner-city, tertiary care hospitals in Chicago. The patients were discharged from the hospitals on daily long-term high-dose oral vitamin K₁ (VK₁), provided free of charge. However, 2 patients were lost to follow-up prior to safe discontinuation of oral VK₁ therapy. The third patient was treated and followed successfully for 7 months when VK₁ was discontinued. We conclude that prolonged oral VK₁ therapy and follow-up of acute, life-threatening LAAR poisoning are variable and present challenges to healthcare providers. Appropriate practice guidelines to improve patient access and adherence to daily high-dose oral VK₁ therapy and follow-up should be developed and implemented.

Vitamin K: Double Bonds beyond Coagulation Insights into Differences between Vitamin K1 and K2 in Health and Disease

Vitamin K is an essential bioactive compound required for optimal body function. Vitamin K can be present in various isoforms, distinguishable by two main structures, namely, phylloquinone (K1) and menaquinones (K2). The difference in structure between K1 and K2 is seen in different absorption rates, tissue distribution, and bioavailability. Although differing in structure, both act as cofactor for the enzyme gamma-glutamylcarboxylase, encompassing both hepatic and extrahepatic activity. Only carboxylated proteins are active and promote a health profile like hemostasis. Furthermore, vitamin K2 in the form of MK-7 has been shown to be a bioactive compound in regulating osteoporosis, atherosclerosis, cancer and inflammatory diseases without risk of negative side effects or overdosing. This review is the first to highlight differences between isoforms vitamin K1 and K2 by means of source, function, and extrahepatic activity.