Vitamin K2-a neglected player in cardiovascular health: a narrative review

Randomized Comparison of Progression of Atherosclerotic Plaques and Calcification of Coronary Artery in Atrial Fibrillation Patients Treated With Edoxaban Versus Warfarin (The REPRESENT-AF trial)

Although the adverse effects of long-term use of vitamin K oral anticoagulant (OAC), warfarin, on the coronary vasculature are well-established, it remains unknown whether nonvitamin K oral anticoagulants play a role in the attenuation of plaque progression and coronary calcification. This study aimed to compare the changes in atherosclerotic plaques and calcification of the coronary arteries in patients with atrial fibrillation (AF) treated with edoxaban and warfarin. A total of 150 OAC-naïve patients with AF and atherosclerotic lesions on coronary computed tomography angiography (CCTA) were enrolled and randomly assigned to the edoxaban or warfarin treatment groups. All enrolled patients received rosuvastatin 10 mg and 119 patients completed the entire study protocol. A total of 12 months after the assigned OAC treatment, follow-up CCTA was performed and changes in plaque and calcium volumes of the coronary arteries were analyzed. The baseline characteristics of the 2 groups were well-balanced. The percentage of time in therapeutic range in the warfarin group was 61.1%. Compared with the baseline CCTA, there was a significant reduction in plaque volume after 12 months of OAC and rosuvastatin administration in both groups, and the extent of regression did not differ significantly between the groups. The increase in calcium volume was greater in the warfarin group than in the edoxaban group; however, the difference was not significant. In OAC-naïve patients with AF and atherosclerotic coronary lesions who were treated with moderate-intensity statin, edoxaban use did not have a positive effect on atherosclerotic plaques and coronary calcification compared with warfarin use over a 12-month follow-up period.

Vitamin K: a potential missing link in critical illness-a scoping review

BACKGROUND

Vitamin K is essential for numerous physiological processes, including coagulation, bone metabolism, tissue calcification, and antioxidant activity. Deficiency, prevalent in critically ill ICU patients, impacts coagulation and increases the risk of bleeding and other complications. This review aims to elucidate the metabolism of vitamin K in the context of critical illness and identify a potential therapeutic approach.

METHODS

In December 2023, a scoping review was conducted using the PRISMA Extension for Scoping Reviews. Literature was searched in PubMed, Embase, and Cochrane databases without restrictions. Inclusion criteria were studies on adult ICU patients discussing vitamin K deficiency and/or supplementation.

RESULTS

A total of 1712 articles were screened, and 13 met the inclusion criteria. Vitamin K deficiency in ICU patients is linked to malnutrition, impaired absorption, antibiotic use, increased turnover, and genetic factors. Observational studies show higher PIVKA-II levels in ICU patients, indicating reduced vitamin K status. Risk factors include inadequate intake, disrupted absorption, and increased physiological demands. Supplementation studies suggest vitamin K can improve status but not normalize it completely. Vitamin K deficiency may correlate with prolonged ICU stays, mechanical ventilation, and increased mortality. Factors such as genetic polymorphisms and disrupted microbiomes also contribute to deficiency, underscoring the need for individualized nutritional strategies and further research on optimal supplementation dosages and administration routes.

CONCLUSIONS

Addressing vitamin K deficiency in ICU patients is crucial for mitigating risks associated with critical illness, yet optimal management strategies require further investigation.

IMPACT RESEARCH

To the best of our knowledge, this review is the first to address the prevalence and progression of vitamin K deficiency in critically ill patients. It guides clinicians in diagnosing and managing vitamin K deficiency in intensive care and suggests practical strategies for supplementing vitamin K in critically ill patients. This review provides a comprehensive overview of the existing literature, and serves as a valuable resource for clinicians, researchers, and policymakers in critical care medicine.

Reaction Mechanisms of H2S Oxidation by Naphthoquinones

1,4-naphthoquinones (NQs) catalytically oxidize H2S to per- and polysufides and sulfoxides, reduce oxygen to superoxide and hydrogen peroxide, and can form NQ-SH adducts through Michael addition. Here, we measured oxygen consumption and used sulfur-specific fluorophores, liquid chromatography tandem mass spectrometry (LC-MS/MS), and UV-Vis spectrometry to examine H2S oxidation by NQs with various substituent groups. In general, the order of H2S oxidization was DCNQ ~ juglone > 1,4-NQ > plumbagin >DMNQ ~ 2-MNQ > menadione, although this order varied somewhat depending on the experimental conditions. DMNQ does not form adducts with GSH or cysteine (Cys), yet it readily oxidizes H2S to polysulfides and sulfoxides. This suggests that H2S oxidation occurs at the carbonyl moiety and not at the quinoid 2 or 3 carbons, although the latter cannot be ruled out. We found little evidence from oxygen consumption studies or LC-MS/MS that NQs directly oxidize H2S2-4, and we propose that apparent reactions of NQs with inorganic polysulfides are due to H2S impurities in the polysulfides or an equilibrium between H2S and H2Sn. Collectively, NQ oxidation of H2S forms a variety of products that include hydropersulfides, hydropolysulfides, sulfenylpolysulfides, sulfite, and thiosulfate, and some of these reactions may proceed until an insoluble S8 colloid is formed.

The Role of the Receptor Activator of Nuclear Factor Kappa-B Ligand/Osteoprotegerin Ratio in Vascular Diseases: A Therapeutic Approach

Cardiovascular and bone diseases contribute independently to mortality and global health. The exact mechanisms involved in the pathophysiology shared between bone and vascular diseases are not well defined. Endothelial cells and osteoblasts communicate during osteogenesis, thus establishing a connection between angiogenesis and osteogenesis. One shared mechanism may involve osteoprotegerin (OPG) and its ligand Receptor Activator of NF-κB Ligand (RANKL). The RANKL/OPG ratio is an important modulator for the skeletal, immunological, and vascular systems. OPG levels are elevated due to either osteogenic causes or inflammatory responses in the vasculature. The data obtained from clinical and in vitro studies support the role of the RANKL/OPG ratio as a potential marker for the progression of endothelial damage. Therefore, determining the therapeutic approaches for the targeting RANKL/OPG ratio and evaluating its usage as a biomarker in cardiovascular and bone pathophysiology are needed. By integrating the protective and disease-causing role of OPG with its ligand, this review outlines the role of the RANKL/OPG ratio at the molecular level. We also consider targeted therapeutic approaches.

Vitamin A, D, E, and K as Matrix Metalloproteinase-2/9 Regulators That Affect Expression and Enzymatic Activity

Fat-soluble vitamins (vitamin A, D, E, and K) assume a pivotal role in maintaining human homeostasis by virtue of their enzymatic functions. The daily inclusion of these vitamins is imperative to the upkeep of various physiological processes including vision, bone health, immunity, and protection against oxidative stress. Current research highlights fat-soluble vitamins as potential therapeutics for human diseases, especially cancer. Fat-soluble vitamins exert their therapeutic effects through multiple pathways, including regulation of matrix metalloproteinases' (MMPs) expression and enzymatic activity. As MMPs have been reported to be involved in the pathology of various diseases, such as cancers, cardiovascular diseases, and neurological disorders, regulating the expression and/or activity of MMPs could be considered as a potent therapeutic strategy. Here, we summarize the properties of fat-soluble vitamins and their potential as promising candidates capable of effectively modulating MMPs through multiple pathways to treat human diseases.

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.

Effects of Vitamin K2 and D Supplementation on Coronary Artery Disease in Men: A RCT

Background

Extent and progression of coronary artery calcification (CAC) are strong predictors of myocardial infarction and mortality.

Objectives

This study aims to investigate if vitamin K2 and D supplementation can reduce CAC progression.

Methods

A total of 389 participants were randomized to supplementation with vitamin K2 (720 μg/day) and D (25 μg/day) vs placebo in a multicenter double-blinded randomized controlled trial. The primary endpoint (progression of aortic valve calcification) has been reported. This study reports CAC progression in participants with no ischemic heart disease. CT scans were performed at baseline, 12, and 24 months. ΔCAC and coronary plaque volume were evaluated in the entire group and in 2 subgroups. A safety endpoint was the composite of myocardial infarction, coronary revascularization, and all-cause mortality.

Results

In total, 304 participants (male, mean age 71 years) were identified. The intervention and placebo group both increased in mean CAC scores from baseline to 24-month follow-up (Δ203 vs Δ254 AU, P = 0.089). In patients with CAC scores ≥400 AU, CAC progression was lower by intervention (Δ288 vs Δ380 AU, P = 0.047). Plaque analyses showed no significant difference in progression of noncalcified plaque volume (Δ-6 vs Δ46 mm3, P = 0.172). Safety events were fewer in participants receiving supplementation (1.9% vs 6.7%, P = 0.048).

Conclusions

Patients with no prior ischemic heart disease randomized to vitamin K2 and D supplementation had no significant reduction in mean CAC progression over a 2-year follow-up compared to placebo. Although the primary endpoint is neutral, differential responses to supplementation in those with CAC scores ≥400 AU and in safety endpoints are hypothesis-generating for future studies.

Co-supplementation of Vitamin K2 and Selenium Synergistically Improves Metabolic Status and Reduces Cardiovascular Risk Markers in Dyslipidemic Rabbits

This work investigated the impact of vitamin K2 and selenium co-supplementation on metabolic profile and indicators of cardiovascular health in dyslipidemic rabbits. Fifty adult male rabbits were equally allocated into 5 groups: Control group, Dyslipidemic group: received 0.5% cholesterol in diet for 12 weeks, groups 3, 4 and 5 dyslipidemic rabbits daily treated with vitamin K2 (10 mg/kg bw) or/and selenium (1 mg/kg bw) for 8 weeks. Co-supplementation of vitamin K2 and selenium significantly decreased body weight gain and blood pressure elevation in dyslipidemic rabbits compared to un-treated ones. Consuming vitamin K2 plus selenium also markedly lowered serum lipids encompassing cholesterol, triglycerides and LDL and elevated HDL relative to placebo. Additionally, such co-supplementation reduced fasting glucose and insulin, enhancing insulin sensitivity with respect to placebo. Regarding cardiovascular risk markers, dyslipidemic rabbits received vitamin K2 concurrently with selenium displayed lower levels of atherogenic index (LDL/HDL), serum C-reactive protein, heart fatty acid-binding protein and asymmetric dimethylarginine as well as aortic ox-LDL, lipid peroxidation and calcium but higher levels of serum nitric oxide and aortic total antioxidants than un-treated ones. Concomitant administration of vitamin K2 and selenium improved metabolic profile, markers of cardiovascular health and atherosclerosis in dyslipidemic rabbits.

Cheese consumption and multiple health outcomes: an umbrella review and updated meta-analysis of prospective studies

This umbrella review aims to provide a systematic and comprehensive overview of current evidence from prospective studies on the diverse health effects of cheese consumption. We searched PubMed, Embase, and Cochrane Library to identify meta-analyses/pooled analyses of prospective studies examining the association between cheese consumption and major health outcomes from inception to August 31, 2022. We reanalyzed and updated previous meta-analyses and performed de novo meta-analyses with recently published prospective studies, where appropriate. We calculated the summary effect size, 95% prediction confidence intervals, between-study heterogeneity, small-study effects, and excess significance bias for each health outcome. We identified 54 eligible articles of meta-analyses/pooled analyses. After adding newly published original articles, we performed 35 updated meta-analyses and 4 de novo meta-analyses. Together with 8 previous meta-analyses, we finally included 47 unique health outcomes. Cheese consumption was inversely associated with all-cause mortality (highest compared with lowest category: RR = 0.95; 95% CI: 0.92, 0.99), cardiovascular mortality (RR = 0.93; 95% CI: 0.88, 0.99), incident cardiovascular disease (CVD) (RR = 0.92; 95% CI: 0.89, 0.96), coronary heart disease (CHD) (RR = 0.92; 95% CI: 0.86, 0.98), stroke (RR = 0.93; 95% CI: 0.89, 0.98), estrogen receptor-negative (ER-) breast cancer (RR = 0.89; 95% CI: 0.82, 0.97), type 2 diabetes (RR = 0.93; 95% CI: 0.88, 0.98), total fracture (RR = 0.90; 95% CI: 0.86, 0.95), and dementia (RR = 0.81; 95% CI: 0.66, 0.99). Null associations were found for other outcomes. According to the NutriGrade scoring system, moderate quality of evidence was observed for inverse associations of cheese consumption with all-cause and cardiovascular mortality, incident CVD, CHD, and stroke, and for null associations with cancer mortality, incident hypertension, and prostate cancer. Our findings suggest that cheese consumption has neutral to moderate benefits for human health.

Redox and Nucleophilic Reactions of Naphthoquinones with Small Thiols and Their Effects on Oxidization of H2S to Inorganic and Organic Hydropolysulfides and Thiosulfate

Naphthoquinone (1,4-NQ) and its derivatives (NQs, juglone, plumbagin, 2-methoxy-1,4-NQ, and menadione) have a variety of therapeutic applications, many of which are attributed to redox cycling and the production of reactive oxygen species (ROS). We previously demonstrated that NQs also oxidize hydrogen sulfide (H₂S) to reactive sulfur species (RSS), potentially conveying identical benefits. Here we use RSS-specific fluorophores, mass spectroscopy, EPR and UV-Vis spectrometry, and oxygen-sensitive optodes to examine the effects of thiols and thiol-NQ adducts on H₂S-NQ reactions. In the presence of glutathione (GSH) and cysteine (Cys), 1,4-NQ oxidizes H₂S to both inorganic and organic hydroper-/hydropolysulfides (R₂S_n, R=H, Cys, GSH; n = 2-4) and organic sulfoxides (GS_nOH, n = 1, 2). These reactions reduce NQs and consume oxygen via a semiquinone intermediate. NQs are also reduced as they form adducts with GSH, Cys, protein thiols, and amines. Thiol, but not amine, adducts may increase or decrease H₂S oxidation in reactions that are both NQ- and thiol-specific. Amine adducts also inhibit the formation of thiol adducts. These results suggest that NQs may react with endogenous thiols, including GSH, Cys, and protein Cys, and that these adducts may affect both thiol reactions as well as RSS production from H₂S.

Can Bone-Specific Alkaline Phosphatase be a Marker of Vascular Calcification in Type 2 Diabetes Mellitus?

Background and Aims

Alkaline phosphatase (ALP) enzyme has been linked to vascular calcification. Unexplained elevations in serum ALP levels have been reported in patients with type 2 diabetes mellitus (T2DM). We assessed bone-specific alkaline phosphatase (BAP) levels in patients with T2DM who had unexplained ALP elevations and studied the association between BAP and other markers of vascular calcification.

Methods

Patients with T2DM who had high serum ALP in the absence of known causes of ALP elevation were studied. The control group was T2DM patients with normal ALP. We measured the serum levels of BAP along with the leptin, fetuin-A, and vitamin K2 levels. Ankle-brachial index (ABI) was also measured in both groups.

Results

Serum BAP levels were significantly higher in the group with high ALP when compared with the normal ALP group. A significant positive correlation was present between BAP and serum fetuin-A as well as between BAP and Vit K2 levels. There was no correlation between BAP and serum leptin. ABI was comparable between the two groups.

Conclusions

Patients with T2DM may have unexplained elevation in ALP due to an increase in BAP. Elevation in BAP may be associated with other markers of vascular calcification suggesting an increased risk of vascular calcification.

ABCG5 and ABCG8 Are Involved in Vitamin K Transport

ATP-binding cassette protein G5 (ABCG5)/ABCG8 heterodimer exports cholesterol from cells, while Niemann-Pick C1-like 1 (NPC1L1) imports cholesterol and vitamin K. We examined whether ABCG5/ABCG8 transports vitamin K similar to NPC1L1. Since high concentrations of vitamin K₃ show cytotoxicity, the cytoprotective effects of ABCG5/ABCG8 were examined. BHK cells expressing ABCG5/ABCG8 were more resistant to vitamin K₃ cytotoxicity than control cells, suggesting that ABCG5/ABCG8 transports vitamin K₃ out of cells. The addition of vitamin K₁ reversed the effects of ABCG5/ABCG8, suggesting that vitamin K₁ competitively inhibits the transport of vitamin K₃. To examine the transport of vitamin K₁ by ABCG5/ABCG8, vitamin K₁ levels in the medium and cells were measured. Vitamin K₁ levels in cells expressing ABCG5/ABCG8 were lower than those in control cells, while vitamin K₁ efflux increased in cells expressing ABCG5/ABCG8. Furthermore, the biliary vitamin K₁ concentration in Abcg5/Abcg8-deficient mice was lower than that in wild-type mice, although serum vitamin K₁ levels were not affected by the presence of Abcg5/Abcg8. These findings suggest that ABCG5 and ABCG8 are involved in the transport of sterols and vitamin K. ABCG5/ABCG8 and NPC1L1 might play important roles in the regulation of vitamin K absorption and excretion.

Pre-procedural oral anticoagulant use is associated with cardiovascular events in women after transcatheter aortic valve replacement: An analysis from the WIN-TAVI cohort

BACKGROUND

Transcatheter aortic valve implantation (TAVI) has become an accepted treatment for patients with severe aortic stenosis (AS). Predicting which patients are at risk for adverse clinical outcomes after TAVI remains difficult, especially in women.

AIM

To identify predictors of adverse events in the WIN-TAVI cohort.

METHODS

The WIN-TAVI study is an observational registry of 1019 women undergoing TAVI for severe symptomatic AS. Follow-up was 1 year. The primary outcome was defined according to VARC-2: a composite of mortality, stroke, myocardial infarction or hospitalization for valve-related symptoms or heart failure. The secondary outcome was a composite of cardiovascular mortality or hospitalization for valve-related symptoms or heart failure.

RESULTS

We included 1019 women with severe AS (mean age of 82.5 ± 6.3 years). At 1 year, 16.4% of the patients experienced the primary endpoint and 12.6% the secondary endpoint. The use of oral anticoagulants (OAC) was the strongest independent predictor of the primary outcome (adjusted hazard ratio [aHR] 1.51, 95% confidence interval [CI] 1.079-2.106, p = 0.016). Independent predictors of the secondary endpoint were age (aHR 1.04 per year, 95% CI 1.01-1.074, p = 0.016) and use of OAC (aHR: 1.79, 95% CI 1.24-2.60, p = 0.002). OAC use was not associated with higher bleeding risk.

CONCLUSION

Pre-procedural use of OAC was the strongest predictor of adverse outcomes during 1-year follow-up, likely reflecting a combination of high-risk factors and comorbidities, but was not related to increased bleeding risk.

Can Bioactive Food Substances Contribute to Cystic Fibrosis-Related Cardiovascular Disease Prevention?

Advances in cystic fibrosis (CF) care have significantly improved the quality of life and life expectancy of patients. Nutritional therapy based on a high-calorie, high-fat diet, antibiotics, as well as new therapies focused on CFTR modulators change the natural course of the disease. They do so by improving pulmonary function and growing BMI. However, the increased weight of such patients can lead to unwanted long-term cardiovascular effects. People with CF (pwCF) experience several cardiovascular risk factors. Such factors include a high-fat diet and increased dietary intake, altered lipid metabolism, a decrease in the level of fat-soluble antioxidants, heightened systemic inflammation, therapeutic interventions, and diabetes mellitus. PwCF must pay special attention to food and eating habits in order to maintain a nutritional status that is as close as possible to the proper physiological one. They also have to benefit from appropriate nutritional counseling, which is essential in the evolution and prognosis of the disease. Growing evidence collected in the last years shows that many bioactive food components, such as phytochemicals, polyunsaturated fatty acids, and antioxidants have favorable effects in the management of CF. An important positive effect is cardiovascular prevention. The possibility of preventing/reducing cardiovascular risk in CF patients enhances both quality of life and life expectancy in the long run.

Role of Vitamins in Cardiovascular Health: Know Your Facts-Part 2

Cardiovascular disease (CVD) is a major cause of morbidity/mortality world-wide, hence preventive interventions are crucial. Observational data showing beneficial CV effects of vitamin supplements, promoted by self-proclaimed experts, have led to ~50% of Americans using multivitamins; this practice has culminated into a multi-billion-dollar business. However, robust evidence is lacking, and certain vitamins might incur harm. This two-part review focuses on the attributes or concerns about specific vitamin consumption on CVD. The evidence for indiscriminate use of multivitamins indicates no consistent CVD benefit. Specific vitamins and/or combinations are suggested, but further supportive evidence is needed. Data presented in Part 1 indicated that folic acid and certain B-vitamins may decrease stroke, whereas niacin might raise mortality; beta-carotene mediates pro-oxidant effects, which may abate the benefits from other vitamins. In Part 2, data favor the anti-oxidant effects of vitamin C and the anti-atherogenic effects of vitamins C and E, but clinical evidence is inconsistent. Vitamin D may provide CV protection, but data are conflicting. Vitamin K appears neutral. Thus, there are favorable CV effects of individual vitamins (C/D), but randomized/controlled data are lacking. An important caveat regards the potential toxicity of increased doses of fat-soluble vitamins (A/D/E/K). As emphasized in Part 1, vitamins might benefit subjects who are antioxidant-deficient or exposed to high levels of oxidative-stress (e.g., diabetics, smokers, and elderly), stressing the importance of targeting certain subgroups for optimal results. Finally, by promoting CV-healthy balanced-diets, we could acquire essential vitamins and nutrients and use supplements only for specific indications.

Gut microbial evidence chain in high-salt diet exacerbates intestinal aging process

Although excessive salt consumption appears to hasten intestinal aging and increases susceptibility to cardiovascular disease, the molecular mechanism is unknown. In this study, mutual validation of high salt (HS) and aging fecal microbiota transplantation (FMT) in C56BL/6 mice was used to clarify the molecular mechanism by which excessive salt consumption causes intestinal aging. Firstly, we observed HS causes vascular endothelial damage and can accelerate intestinal aging associated with decreased colon and serum expression of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and increased malondialdehyde (MDA); after transplantation with HS fecal microbiota in mice, vascular endothelial damage and intestinal aging can also occur. Secondly, we also found intestinal aging and vascular endothelial damage in older mice aged 14 months; and after transplantation of the older mice fecal microbiota, the same effect was observed in mice aged 6–8 weeks. Meanwhile, HS and aging significantly changed gut microbial diversity and composition, which was transferable by FMT. Eventually, based on the core genera both in HS and the aging gut microbiota network, a machine learning model was constructed which could predict HS susceptibility to intestinal aging. Further investigation revealed that the process of HS-related intestinal aging was highly linked to the signal transduction mediated by various bacteria. In conclusion, the present study provides an experimental basis of potential microbial evidence in the process of HS related intestinal aging. Even, avoiding excessive salt consumption and actively intervening in gut microbiota alteration may assist to delay the aging state that drives HS-related intestinal aging in clinical practice.

Role of Vitamin K in Chronic Kidney Disease: A Focus on Bone and Cardiovascular Health

Chronic kidney disease (CKD) is commonly associated with vitamin K deficiency. Some of the serious complications of CKD are represented by cardiovascular disease (CVD) and skeletal fragility with an increased risk of morbidity and mortality. A complex pathogenetic link between hormonal and ionic disturbances, bone tissue and metabolism alterations, and vascular calcification (VC) exists and has been defined as chronic kidney disease–mineral and bone disorder (CKD-MBD). Poor vitamin K status seems to have a key role in the progression of CKD, but also in the onset and advance of both bone and cardiovascular complications. Three forms of vitamin K are currently known: vitamin K1 (phylloquinone), vitamin K2 (menaquinone), and vitamin K3 (menadione). Vitamin K plays different roles, including in activating vitamin K-dependent proteins (VKDPs) and in modulating bone metabolism and contributing to the inhibition of VC. This review focuses on the biochemical and functional characteristics of vitamin K vitamers, suggesting this nutrient as a possible marker of kidney, CV, and bone damage in the CKD population and exploring its potential use for promoting health in this clinical setting. Treatment strategies for CKD-associated osteoporosis and CV disease should include vitamin K supplementation. However, further randomized clinical studies are needed to assess the safety and the adequate dosage to prevent these CKD complications.