Regulation of bone remodeling by vitamin K2

An analysis of vitamin K status in Chinese healthy children aged 0-18 years

BACKGROUND

Vitamin K (VK), an essential fat-soluble nutrient, exists in two primary forms, vitamin K1 (VK1), and vitamin K2 (VK2). VK1 plays an essential role in blood coagulation, while VK2 plays a crucial role in managing bone calcification, supporting bone strength and health. However, comprehensive epidemiological data on VK remains sparse, particularly in children. This study aims to evaluate the levels and characteristics of VK in children of Wenzhou area, China.

METHODS

A total of 3,342 children undergoing routine physical examinations in the outpatient department from December 2020 to August 2022 were recruited. The levels of VK (including VK1 and menaquinones (MK-4), a major form of VK2) and 25-hydroxy vitamin D (25(OH)D) in fasting serum samples from these children were measured using high-performance liquid chromatography-tandem mass spectrometry. The study analyzed the levels and distribution of VK and 25(OH)D across different sex, age, and weight groups, and explored their potential related factors.

RESULTS

The median serum levels of MK-4 and VK1 were 0.12 (0.07, 0.21) ng/ml and 0.33 (0.18, 0.57) ng/ml, respectively. The reference ranges of MK-4 and VK1 were 0.01-0.58 ng/ml and 0.03-1.48 ng/ml, respectively. The median serum 25(OH)D level was 21.26 (17.30, 25.35) ng/ml. Moreover, there were no significant variations in the levels of MK-4 and VK1 across different age and sex groups. The level of MK-4 in the underweight group was significantly higher than that in the normal weight group. MK-4 level reached its peak in summer, while the VK1 concentration was at its lowest. Furthermore, a very weak positive correlation was revealed between MK-4 and VK1 levels.

CONCLUSION

In this study, we defined the median values and reference ranges of MK-4 and VK1 in a sample of Chinese children aged 0-18 years. MK-4 levels were higher in underweight children. Both MK-4 and VK1 levels exhibited seasonal variations. Further research is needed to explore the factors affecting MK-4 and VK1 levels.

The Importance of Vitamin K and the Combination of Vitamins K and D for Calcium Metabolism and Bone Health: A Review

The aim of the present review is to discuss the roles of vitamin K (phylloquinone or menaquinones) and vitamin K-dependent proteins, and the combined action of the vitamins K and D, for the maintenance of bone health. The most relevant vitamin K-dependent proteins in this respect are osteocalcin and matrix Gla-protein (MGP). When carboxylated, these proteins appear to have the ability to chelate and import calcium from the blood to the bone, thereby reducing the risk of osteoporosis. Carboxylated osteocalcin appears to contribute directly to bone quality and strength. An adequate vitamin K status is required for the carboxylation of MGP and osteocalcin. In addition, vitamin K acts on bone metabolism by other mechanisms, such as menaquinone 4 acting as a ligand for the nuclear steroid and xenobiotic receptor (SXR). In this narrative review, we examine the evidence for increased bone mineralization through the dietary adequacy of vitamin K. Summarizing the evidence for a synergistic effect of vitamin K and vitamin D3, we find that an adequate supply of vitamin K, on top of an optimal vitamin D status, seems to add to the benefit of maintaining bone health. More research related to synergism and the possible mechanisms of vitamins D3 and K interaction in bone health is needed.

Tobacco as bioenergy and medical plant for biofuels and bioproduction

Tobacco, a widely cultivated crop, has been extensively utilized by humans for an extended period. However, the tobacco industry generates a significant amount of organic waste, and the effective utilization of this tobacco waste has been limited. Currently, most tobacco waste is either recycled as reconstituted tobacco sheets or disposed of in landfills. However, tobacco possesses far more potential value than just these applications. This article provides an overview of the diverse uses of tobacco waste in agriculture, medicine, chemical engineering, and energy sectors. In the realm of agriculture, tobacco waste finds primary application as fertilizers and pesticides. In medical applications, the bioactive compounds present in tobacco are fully harnessed, resulting in the production of phenols, solanesol, polysaccharides, proteins, and even alkaloids. These bioactive compounds exhibit beneficial effects on human health. Additionally, the applications of tobacco waste in chemical engineering and energy sectors are centered around the utilization of lignocellulosic compounds and certain fuels. Chemical platform compounds derived from tobacco waste, as well as selected fuel sources, play a significant role in these areas. The rational utilization of tobacco waste represents a promising prospect, particularly in the present era when sustainable development is widely advocated. Moreover, this approach holds significant importance for enhancing energy utilization.

The Microbial Revolution in the World of Joint Replacement Surgery

Background

The prevalence of revision surgery due to aseptic loosening and periprosthetic joint infection (PJI) following total hip and knee arthroplasty is growing. Strategies to prevent the need for revision surgery and its associated health-care costs and patient morbidity are needed. Therapies that modulate the gut microbiota to influence bone health and systemic inflammation are a novel area of research.

Methods

A literature review of preclinical and clinical peer-reviewed articles relating to the role of the gut microbiota in bone health and PJI was performed.

Results

There is evidence that the gut microbiota plays a role in maintaining bone mineral density, which can contribute to osseointegration, osteolysis, aseptic loosening, and periprosthetic fractures. Similarly, the gut microbiota influences gut permeability and the potential for bacterial translocation to the bloodstream, increasing susceptibility to PJI.

Conclusions

Emerging evidence supports the role of the gut microbiota in the development of complications such as aseptic loosening and PJI after total hip or knee arthroplasty. There is a potential for microbial therapies such as probiotics or fecal microbial transplantation to moderate the risk of developing these complications. However, further investigation is required.

Clinical Relevance

Modulation of the gut microbiota may influence patient outcomes following total joint arthroplasty.

Can vitamins improve periodontal wound healing/regeneration?

Periodontitis is a complex inflammatory disorder of the tooth supporting structures, associated with microbial dysbiosis, and linked to a number if systemic conditions. Untreated it can result in an irreversible damage to the periodontal structures and eventually teeth loss. Regeneration of the lost periodontium requires an orchestration of a number of biological events on cellular and molecular level. In this context, a set of vitamins have been advocated, relying their beneficial physiological effects, to endorse the biological regenerative events of the periodontium on cellular and molecular levels. The aim of the present article is to elaborate on the question whether or not vitamins improve wound healing/regeneration, summarizing the current evidence from in vitro, animal and clinical studies, thereby shedding light on the knowledge gap in this field and highlighting future research needs. Although the present review demonstrates the current heterogeneity in the available evidence and knowledge gaps, findings suggest that vitamins, especially A, B, E, and CoQ10, as well as vitamin combinations, could exert positive attributes on the periodontal outcomes in adjunct to surgical or nonsurgical periodontal therapy.

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.

Role of vitamins beyond vitamin D3 in bone health and osteoporosis (Review)

The objective of the present review was to summarize the molecular mechanisms associated with the effects of the vitamins A, C, E and K, and group B vitamins on bone and their potential roles in the development of osteoporosis. Epidemiological findings have demonstrated an association between vitamin deficiency and a higher risk of developing osteoporosis; vitamins are positively related to bone health upon their intake at the physiological range. Excessive vitamin intake can also adversely affect bone formation, as clearly demonstrated for vitamin A. Vitamins E (tocopherols and tocotrienols), K2 (menaquinones 4 and 7) and C have also been shown to promote osteoblast development through bone morphogenetic protein (BMP)/Smad and Wnt/β‑catenin signaling, as well as the TGFβ/Smad pathway (α‑tocopherol). Vitamin A metabolite (all‑trans retinoic acid) exerts both inhibitory and stimulatory effects on BMP‑ and Wnt/β‑catenin‑mediated osteogenesis at the nanomolar and micromolar range, respectively. Certain vitamins significantly reduce receptor activator of nuclear factor kappa‑B ligand (RANKL) production and RANKL/RANK signaling, while increasing the level of osteoprotegerin (OPG), thus reducing the RANKL/OPG ratio and exerting anti‑osteoclastogenic effects. Ascorbic acid can both promote and inhibit RANKL signaling, being essential for osteoclastogenesis. Vitamin K2 has also been shown to prevent vascular calcification by activating matrix Gla protein through its carboxylation. Therefore, the maintenance of a physiological intake of vitamins should be considered as a nutritional strategy for the prevention of osteoporosis.

A Case Control Study Evaluating the Relationship between Vitamin K2 Serum Level and Periodontitis

BACKGROUND AND AIM

Vitamin K2 (VK2) is an essential co-factor for bone metabolism. There is still very little data regarding possible VK2 relation to periodontitis. This study aimed to investigate any potential link between VK2 serum level and the severity of periodontitis in comparison to a control group of healthy individuals. The trial was performed on 100 patients among whom 50 were diagnosed with periodontitis. The patients underwent full clinical periodontal and radiological examination. The VK2 serum level was assessed using the ELISA kit (Gla-type osteocalcin EIA Kit, Takara, Kusatsu). Patients with periodontitis had mean serum levels of VK2 significantly lower (0.27 ± 0.06 nmol/L; p < 0.001) than the control group (0.43 ± 0.09 nmol/L; p < 0.001) regardless of the patient's age or sex. The VK2 serum level decreased with the severity of periodontitis with the lowest level in stage IV of the disease (0.19 ± 0.01 nmol/L; p < 0.001). Also, a significant drop was noticed between the grades of periodontitis. Individuals with localized forms of the disease had significantly lower VK2 levels (0.26 ± 0.006 nmol/L; p < 0.001) in comparison to subjects with generalized periodontitis (0.30 ± 0.01 nmol/L; p < 0.001). The VK2 serum levels were also associated with most of the clinical parameters such as bleeding on probing (-0.805, 95% CI: -0.894 to -0.654, p < 0.001), attachment loss (-0.752, 95% CI: -0.862 to -0.574, p < 0.001), and bone loss (-0.656, 95% CI: -0.801 to -0.439, p < 0.001). In the present study, the VK2 serum level was correlated to periodontitis, and its severity, complexity, extension, and grade. The range of VK2 was decreasing together with the worsening of all clinical parameters of periodontitis.

A Rare Skeletal Disorder, Fibrous Dysplasia: A Review of Its Pathogenesis and Therapeutic Prospects

Fibrous dysplasia (FD) is a rare, non-hereditary skeletal disorder characterized by its chronic course of non-neoplastic fibrous tissue buildup in place of healthy bone. A myriad of factors have been associated with its onset and progression. Perturbation of cell-cell signaling networks and response outputs leading to disrupted building blocks, incoherent multi-level organization, and loss of rigid structural motifs in mineralized tissues are factors that have been identified to participate in FD induction. In more recent years, novel insights into the unique biology of FD are transforming our understandings of its pathology, natural discourse of the disease, and treatment prospects. Herein, we built upon existing knowledge with recent findings to review clinical, etiologic, and histological features of FD and discussed known and potential mechanisms underlying FD manifestations. Subsequently, we ended on a note of optimism by highlighting emerging therapeutic approaches aimed at either halting or ameliorating disease progression.

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.

Vascular calcification: Molecular mechanisms and therapeutic interventions

Vascular calcification (VC) is recognized as a pathological vascular disorder associated with various diseases, such as atherosclerosis, hypertension, aortic valve stenosis, coronary artery disease, diabetes mellitus, as well as chronic kidney disease. Therefore, it is a life-threatening state for human health. There were several studies targeting mechanisms of VC that revealed the importance of vascular smooth muscle cells transdifferentiating, phosphorous and calcium milieu, as well as matrix vesicles on the progress of VC. However, the underlying molecular mechanisms of VC need to be elucidated. Though there is no acknowledged effective therapeutic strategy to reverse or cure VC clinically, recent evidence has proved that VC is not a passive irreversible comorbidity but an active process regulated by many factors. Some available approaches targeting the underlying molecular mechanism provide promising prospects for the therapy of VC. This review aims to summarize the novel findings on molecular mechanisms and therapeutic interventions of VC, including the role of inflammatory responses, endoplasmic reticulum stress, mitochondrial dysfunction, iron homeostasis, metabolic imbalance, and some related signaling pathways on VC progression. We also conclude some recent studies on controversial interventions in the clinical practice of VC, such as calcium channel blockers, renin-angiotensin system inhibitions, statins, bisphosphonates, denosumab, vitamins, and ion conditioning agents.

E, K, B5, B6, and B9 vitamins and their specific immunological effects evaluated by flow cytometry

It has been proven that vitamins play an essential role in preventing certain diseases since ancient times. It is thus fruitless to approach the roles of vitamins without making reference to the techniques used in evaluating the effects of these micronutrients. Therefore, the aim of this paper was to summarize the immunological effects of E, K, B5, B6, and B9 vitamins evaluated by flow cytometry. Some of these significant effects were presented and discussed: (a) The role of vitamins E in the prevention and treatment of different types of cancer. (b) The properties of K vitamins in the development and maintenance of pheochromocytoma Cell Line 12 (PC12) cells in Parkinson's disease; (c) The improvement effect of vitamin B5 on the loss of bone mass in low estrogen conditions; (d) The anticancer role of vitamins B6. (e) The role of Vitamin B9 in the regulation of Treg cells. As such, the flow cytometry technique used to assess these properties is essential to evaluate the immunomodulatory effects of certain vitamins. The technique undergoes constant improvement which makes it possible to determine several parameters with a role in the modulation of the immune function and at the same time increase the accuracy of the methods that highlight them.

Strategies of Macrophages to Maintain Bone Homeostasis and Promote Bone Repair: A Narrative Review

Bone homeostasis (a healthy bone mass) is regulated by maintaining a delicate balance between bone resorption and bone formation. The regulation of physiological bone remodeling by a complex system that involves multiple cells in the skeleton is closely related to bone homeostasis. Loss of bone mass or repair of bone is always accompanied by changes in bone homeostasis. However, due to the complexity of bone homeostasis, we are currently unable to identify all the mechanisms that affect bone homeostasis. To date, bone macrophages have been considered a third cellular component in addition to osteogenic spectrum cells and osteoclasts. As confirmed by co-culture models or in vivo experiments, polarized or unpolarized macrophages interact with multiple components within the bone to ensure bone homeostasis. Different macrophage phenotypes are prone to resorption and formation of bone differently. This review comprehensively summarizes the mechanisms by which macrophages regulate bone homeostasis and concludes that macrophages can control bone homeostasis from osteoclasts, mesenchymal cells, osteoblasts, osteocytes, and the blood/vasculature system. The elaboration of these mechanisms in this narrative review facilitates the development of macrophage-based strategies for the treatment of bone metabolic diseases and bone defects.

Periodontal ligament stem cell-based bioactive constructs for bone tissue engineering

Objectives: Stem cell-based tissue engineering approaches are promising for bone repair and regeneration. Periodontal ligament stem cells (PDLSCs) are a promising cell source for tissue engineering, especially for maxillofacial bone and periodontal regeneration. Many studies have shown potent results via PDLSCs in bone regeneration. In this review, we describe recent cutting-edge researches on PDLSC-based bone regeneration and periodontal tissue regeneration. Data and sources: An extensive search of the literature for papers related to PDLSCs-based bioactive constructs for bone tissue engineering was made on the databases of PubMed, Medline and Google Scholar. The papers were selected by three independent calibrated reviewers. Results: Multiple types of materials and scaffolds have been combined with PDLSCs, involving xeno genic bone graft, calcium phosphate materials and polymers. These PDLSC-based constructs exhibit the potential for bone and periodontal tissue regeneration. In addition, various osteo inductive agents and strategies have been applied with PDLSCs, including drugs, biologics, gene therapy, physical stimulation, scaffold modification, cell sheets and co-culture. Conclusoin: This review article demonstrates the great potential of PDLSCs-based bioactive constructs as a promising approach for bone and periodontal tissue regeneration.

Vitamin D as a Possible COVID-19 Prevention Strategy

Vitamin D is no longer considered an agent only affecting calcium phosphate metabolism. A number of studies over the past few years have demonstrated its role in immunomodulation and its influence on the development and functioning of the brain and nervous system. In the current epidemiological crisis caused by coronavirus disease 2019 (COVID-19), the immunoprotective role of vitamin D has been discussed by some authors regarding whether it contributes to protection against this serious disease or whether its use does not play a role. Non-standard approaches taken by laboratories in examining the serum levels of the vitamin D metabolite calcidiol have contributed to inconsistent results. We examined the serum of 60 volunteers in the spring and autumn of 2021 who declared whether they were taking vitamin D at the time of sampling. Furthermore, the tested participants noted whether they had experienced COVID-19. A newly developed liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was used to measure calcidiol levels. The analysis of variance (ANOVA) model of Statgraphics Centurion 18 statistical software from Statgraphics Technologies was used for calculations. The results of this study showed that those who took vitamin D suffered significantly less often from COVID-19 than those who did not take vitamin D.

New Insights into Vitamin K-From Its Natural Sources through Biological Properties and Chemical Methods of Quantitative Determination

Vitamin K is one of the many health-promoting substances whose impact on the human body has been underestimated until recently. However, recently published research results have changed this situation, prompting some researchers to consider it a new panacea for diseases of old age. The result is a significant increase in interest in the accurate analysis of vitamin K in various types of samples, ranging from food, through dietary supplements, to biological matrices and clinical trials, both observational and interventional. This review summarizes the current state of knowledge about the proven and speculated biological activity of vitamin K and its importance for the world's aging societies, including the methods used for its isolation and analysis in various matrices types. Of all the analytical methods, the currently preferred methods of choice for the direct analysis of vitamin K are chromatographic methods, in particular liquid chromatography-tandem mass spectrometry. This technique, despite its sensitivity and selectivity, requires an appropriate stage of sample preparation. As there is still room for improvement in the efficiency of these methods, especially at the sample preparation stage, this review shows the directions that need to be taken to make these methods faster, more efficient and more environmentally friendly.

Vegan nutrition: a preliminary guide for health professionals

Since the beginning of the 21st century, interest in vegan diets has been rapidly increasing in most countries. Misconceptions about vegan diets are widespread among the general population and health professionals. Vegan diets can be health-promoting and may offer certain important advantages compared to typical Western (and other mainstream) eating patterns. However, adequate dietary sources/supplements of nutrients of focus specific to vegan diets should be identified and communicated. Without supplements/fortified foods, severe vitamin B12 deficiency may occur. Other potential nutrients of focus are calcium, vitamin D, iodine, omega-3 fatty acids, iron, zinc, selenium, vitamin A, and protein. Ensuring adequate nutrient status is particularly important during pregnancy, lactation, infancy, and childhood. Health professionals are often expected to be able to provide advice on the topic of vegan nutrition, but a precise and practical vegan nutrition guide for health professionals is lacking. Consequently, it is important and urgent to provide such a set of dietary recommendations. It is the aim of this article to provide vegan nutrition guidelines, based on current evidence, which can easily be communicated to vegan patients/clients, with the goal of ensuring adequate nutrient status in vegans.

Fermented soybean foods: A review of their functional components, mechanism of action and factors influencing their health benefits

After thousands of years of evolution and development, traditional fermented soybean foods, with their unique charm, have gained a stable place in the global market. With the explosive development of modern biological technologies, some traditional fermented soybean foods that possess health-promoting benefits are gradually appearing. Physiologically active substances in fermented soybean foods have received extensive attention in recent decades. This review addresses the potential health benefits of several representative fermented soybean foods, as well as the action mechanism and influencing factors of their functional components. Phenolic compounds, low-molecular-weight peptides, melanoidins, furanones and 3-hydroxyanthranilic acid are the antioxidative components predominantly found in fermented soybean foods. Angiotensin I-converting enzyme inhibitory peptides and γ-aminobutyric acid isolated from fermented soy foods provide potential selectivity for hypertension therapy. The potential anti-inflammatory bioactive components in fermented soybean foods include γ-linolenic acid, butyric acid, soy sauce polysaccharides, 2S albumin and isoflavone glycones. Deoxynojirimycin, genistein, and betaine possess high activity against α-glucosidase. Additionally, fermented soybean foods contain neuroprotective constituents, including indole alkaloids, nattokinase, arbutin, and isoflavone vitamin B12. The anticancer activities of fermented soybean foods are associated with surfactin, isolavone, furanones, trypsin inhibitors, and 3-hydroxyanthranilic acid. Nattokinase is highly correlated with antioxidant activity. And a high level of menaquinones-7 is linked to protection against neurodegenerative diseases. Sufficiently recognizing and exploiting the health benefits and functional components of traditional fermented soybean foods could provide a new strategy in the development of the food fermentation industry.

Concurrent Treatment with Vitamin K2 and D3 on Spine Fusion in Patients with Osteoporosis-Associated Lumbar Degenerative Disorders

STUDY DESIGN

A prospective and nonrandomized concurrent controlled trial.

OBJECTIVE

To address the early effects of concurrent treatment with vitamin K2 and vitamin D3 on fusion rates in patients who have undergone spinal surgery.

SUMMARY OF BACKGROUND DATA

Intervertebral pseudarthrosis has been reported after transforaminal lumbar interbody fusion (TLIF) or posterior lumbar interbody fusion (PLIF), especially in patients with osteopenia or osteoporosis. No study has assessed the early effects of concurrent treatment with vitamin K2 and vitamin D3 on fusion rates.

METHODS

Patients with osteopenia or osteoporosis who underwent TLIF or PLIF in our department were included. Patients in the VK2+VD3 group received vitamin K2, vitamin D3, and calcium treatment, whereas subjects in the control group only received calcium and vitamin D3. Spine fusion was evaluated by computed tomography. The Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOA-BPEQ) and visual analog scale (VAS) were used to assess the clinical and neurological symptoms. Bone mineral density (BMD) and bone metabolism markers were measured for osteoporotic evaluation.

RESULTS

Seventy-eight patients were included, and nine patients subsequently discontinued because of 2019-nCoV. At six months postoperatively, complete fusion rates were significantly higher in the VK2+VD3 group than that in the control group (91.18% vs 71.43%, P = 0.036). At six months postoperatively, BMD was increased in the VK2+VD3 group and was higher than that in the control group, although there was no significant difference. At three months postoperatively, a significant increase in procollagen type I amino terminal propeptide (91.81%) and a slight decrease in C-terminal end peptide (8.06%) were observed in the VK2+VD3 group. In both groups, the JOA-BPEQ and VAS scores were significantly improved after spine surgery.

CONCLUSION

Administration of vitamin K2 and vitamin D3 can increase lumbar interbody fusion rates, improve clinical symptoms, promote bone information, and avoid further decline in BMD within six months after TLIF or PLIF.Level of Evidence: 3.

The combined effect of vitamin K and calcium on bone mineral density in humans: a meta-analysis of randomized controlled trials

Background

With the increasing incidence of osteoporosis, vitamin K and calcium have been linked to bone mineral density (BMD) and undercarboxylated osteocalcin (UcOC) in many studies, but the results of studies of the combined effect of vitamin K and calcium on BMD and UcOC in humans have been inconsistent. We conducted a systematic review of randomized controlled trials to assess the effect of this combination treatment on BMD and UcOC in humans.

Methods

A search for articles was conducted using PubMed, Embase, and the Cochrane Library database up to March 2021 (no language restrictions). We also reviewed the reference lists of the relevant publications and reviews to locate additional publications. The standard mean difference (SMD) was used as the primary measure of effect size. Our main endpoints were lumbar BMD, femoral neck BMD, hip BMD, total femoral BMD, and UcOC from baseline to end point. We performed subgroup analysis, heterogeneity testing, and assessment of publication bias.

Results

A total of 1346 patients from 10 randomized controlled trials were included in the meta-analysis. The forest plot analysis revealed that vitamin K combined with calcium was associated with a higher lumbar spine BMD compared to controls. The SMD was 0.20 [95% confidence interval (CI): 0.07 to 0.32]. Vitamin K and calcium supplementation led to a significant decrease in UcOC (SMD: − 1.71, 95% CI: − 2.45 to − 0.96). Subgroup analysis showed that vitamin K2 and vitamin K1 had SMDs of 0.30 (95% CI: 0.10 to 0.51) and SMDs of 0.14 (95% CI: − 0.02 to 0.29), and calcium dosages of ≤ 1000 mg/d or > 1000 mg/d had SMDs of 0.19 (95% CI: 0.05 to 0.32) and 0.26 (95% CI: − 0.04 to 0.55).

Conclusion

The combination of vitamin K and calcium has a positive effect on lumbar BMD and decreases the level of UcOC.

Registration: The protocol for this meta-analysis was registered at the International Prospective Register of Systematic Reviews (CRD42021251825).

Nicorandil Inhibits Osteoclast Formation Base on NF-κB and p-38 MAPK Signaling Pathways and Relieves Ovariectomy-Induced Bone Loss

Osteolytic bone disorders are characterized by an overall reduction in bone mineral density which enhances bone ductility and vulnerability to fractures. This disorder is primarily associated with superabundant osteoclast formation and bone resorption activity. Nicorandil (NIC) is a vasodilatory anti-anginal drug with ATP-dependent potassium (KATP) channel openings. However, NIC is adopted to manage adverse cardiovascular and coronary events. Recent research has demonstrated that NIC also possesses anti-inflammatory peculiarity through the regulation of p38 MAPK and NF-κB signaling pathways. Both MAPK and NF-κB signaling pathways play pivotal roles in RANKL-induced osteoclast formation and bone resorption function. Herein, we hypothesized that NIC may exert potential biological effects against osteoclasts, and revealed that NIC dose-dependently suppressed bone marrow macrophage (BMM) precursors to differentiate into TRAP + multinucleated osteoclasts in vitro. Furthermore, osteoclast resorption assays demonstrated anti-resorptive effects exhibited by NIC. NIC had no impact on osteoblast differentiation or mineralization function. Based on Biochemical analyses, NIC relieved RANKL-induced ERK, NF-κB and p38 MAPK signaling without noticeable effects on JNK MAPK activation. However, the attenuation of NF-κB and p38 MAPK activation was sufficient to hamper the downstream induction of c-Fos and NFATc1 expression. Meanwhile, NIC administration markedly protected mice from ovariectomy (OVX)-induced bone loss through in vivo inhibition of osteoclast formation and bone resorption activity. Collectively, this work demonstrated the potential of NIC in the management of osteolytic bone disorders mediated by osteoclasts.

Effect of vitamin K2 and vitamin D3 on bone mineral density in children with acute lymphoblastic leukemia: a prospective cohort study

OBJECTIVES

Current treatment protocols in acute lymphoblastic leukemia (ALL) are associated with high remission rates and long life expectancy, enhancing the importance of quality of life and prevention of treatment-related complications in patient care. As osteoporosis is a frequent complication in patients under chemotherapy, we investigated the effect of vitamin K2 (100 mcg menaquinone-7) and vitamin D3 (10 mcg calcitriol) on bone metabolism in children with ALL.

METHODS

Twenty-nine consecutive patients recently diagnosed with B precursor ALL (B-ALL) and treated according to the Turkish Acute Lymphoblastic Leukemia Berlin Frankfurt Münster 2000 protocol were randomly assigned into study and control groups. The study group (n=15, M/F: 8/7, age 1-14.5 years, mean 6.5 years) received vitamin K2 and vitamin D3 with their chemotherapy, while the control group (n=14, M/F 9/5, age 2-17 years, mean 7.1 years) received chemotherapy only. Serum calcium, phosphorus, magnesium, alkaline phosphatase, bone-specific alkaline phosphatase, uncarboxylated osteocalcin (ucOC), tartrate resistant acid phosphatase 5b, carboxyl terminal procollagen propeptide (PICP), osteoprotegerin (OPG), and receptor activator nuclear kappa B ligand (RANKL) were measured and bone mineral density (BMD) was determined at baseline and first, second, third and sixth months.

RESULTS

The study group had higher serum OPG/RANKL ratio and lower ucOC levels compared to the control group at the first month; PICP levels were higher in the study group at second and third months.

CONCLUSIONS

These results suggest an early beneficial effect of the combination of vitamin K2 and vitamin D3 on BMD in ALL patients especially during the period of intensive steroid therapy in the first months.

New aspects of microbial vitamin K2 production by expanding the product spectrum

Vitamin K2 (menaquinone, MK) is an essential lipid-soluble vitamin with critical roles in blood coagulation and bone metabolism. Chemically, the term vitamin K2 encompasses a group of small molecules that contain a common naphthoquinone head group and a polyisoprenyl side chain of variable length. Among them, menaquinone-7 (MK-7) is the most potent form. Here, the biosynthetic pathways of vitamin K2 and different types of MK produced by microorganisms are briefly introduced. Further, we provide a new aspect of MK-7 production, which shares a common naphthoquinone ring and polyisoprene biosynthesis pathway, by analyzing strategies for expanding the product spectrum. We review the findings of metabolic engineering strategies targeting the shikimate pathway, polyisoprene pathway, and menaquinone pathway, as well as membrane engineering, which provide comprehensive insights for enhancing the yield of MK-7. Finally, the current limitations and perspectives of microbial menaquinone production are also discussed. This article provides in-depth information on metabolic engineering strategies for vitamin K2 production by expanding the product spectrum.

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.

A study of hydrophobins-modified menaquinone-7 on osteoblastic cells differentiation

Menaquinone-7 is involved in bone metabolism and can be used to prevent and treat osteoporosis. However, as a fat-soluble vitamin, menaquinone-7 has poor water solubility. As a surfactant, hydrophobins can change the affinity/hydrophobicity of the covered interface. In this study, menaquinone-7 was modified by hydrophobins, and the different addition ratios were explored. Moreover, Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), and water contact angle (WCA) measurements indicated that hydrophobins effectively bind to menaquinone-7 and greatly increase the hydrophilicity of the surface of menaquinone-7. Studies on the metabolism of MC3T3-E1 cells showed that compared with native menaquinone-7, HGFI-modified menaquinone-7 can significantly promote osteoblast differentiation but inhibit osteoclast differentiation. Besides, the Mito-Tracker Green experiments show that HGFI-modified menaquinone-7 can significantly promote the activity of mitochondria in cells. These findings indicate that hydrophobins can be used as an effective biomaterial to modify menaquinone-7, promote the formation of osteoblasts, and better to bone balance.

Six months vitamin K treatment does not affect systemic arterial calcification or bone mineral density in diabetes mellitus 2

PURPOSE

Vitamin K-dependent proteins are involved in (patho)physiological calcification of the vasculature and the bones. Type 2 diabetes mellitus (DM2) is associated with increased arterial calcification and increased fractures. This study investigates the effect of 6 months vitamin K2 supplementation on systemic arterial calcification and bone mineral density (BMD) in DM2 patients with a history of cardiovascular disease (CVD).

METHODS

In this pre-specified, post hoc analysis of a double-blind, randomized, controlled clinical trial, patients with DM2 and CVD were randomized to a daily, oral dose of 360 µg vitamin K2 or placebo for 6 months. CT scans were made at baseline and follow-up. Arterial calcification mass was quantified in several large arterial beds and a total arterial calcification mass score was calculated. BMD was assessed in all non-fractured thoracic and lumbar vertebrae.

RESULTS

68 participants were randomized, 35 to vitamin K2 (33 completed follow-up) and 33 to placebo (27 completed follow-up). The vitamin K group had higher arterial calcification mass at baseline [median (IQR): 1694 (812-3584) vs 1182 (235-2445)] for the total arterial calcification mass). Six months vitamin K supplementation did not reduce arterial calcification progression (β [95% CI]: - 0.02 [- 0.10; 0.06] for the total arterial calcification mass) or slow BMD decline (β [95% CI]: - 2.06 [- 11.26; 7.30] Hounsfield units for all vertebrae) when compared to placebo.

CONCLUSION

Six months vitamin K supplementation did not halt progression of arterial calcification or decline of BMD in patients with DM2 and CVD. Future clinical trials may want to pre-select patients with very low vitamin K status and longer follow-up time might be warranted. This trial was registered at clinicaltrials.gov as NCT02839044.

Managing acute cancer pain

Cancer-related pain is an ongoing concern for patients and families. Clinicians should include pain management or palliative care specialists who have advanced knowledge in pharmacotherapy and who have the ability to perform interventional procedures to help alleviate patients' pain and reduce opioid use. This article discusses available interventions for patients with cancer pain.

Role of vitamin K2 in bone metabolism: a point of view and a short reappraisal of the literature

Vitamin K₂ (vit K₂) belongs to a large group of fat-soluble compounds whose formulation is MK (menaquinone) (MK-2 to MK-14), that seem to be involved in different biological functions. In particular, vit K₂ has been recently recognized as efficacious and safe in treatment of bone loss, as it contributes to structural integrity of osteocalcin (OC), the major non-collagenous protein typically found in bone matrix. Several studies proved low vit K₂ intake is linked to bone loss and to increased fracture risk in both sexes. Nowadays, vit K₂ supplementation is considered a significant manner to enhance the association of calcium and vitamin D whose role on bone health is largely recognized. On the other hand, vit K₂ may be used alone or with other drugs to preserve bone quality/strength from skeletal degradation after menopause and/or in patients affected by secondary osteoporosis. In this paper, we review the most recent data about vit K₂ on skeleton.

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.

Do Dietary Supplements and Nutraceuticals Have Effects on Dental Implant Osseointegration? A Scoping Review

Several factors affect dental implant osseointegration, including surgical issues, bone quality and quantity, and host-related factors, such as patients' nutritional status. Many micronutrients might play a key role in dental implant osseointegration by influencing some alveolar bone parameters, such as healing of the alveolus after tooth extraction. This scoping review aims to summarize the role of dietary supplements in optimizing osseointegration after implant insertion surgery. A technical expert panel (TEP) of 11 medical specialists with expertise in oral surgery, bone metabolism, nutrition, and orthopedic surgery performed the review following the PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews) model. The TEP identified micronutrients from the "European Union (EU) Register of nutrition and health claims made on foods" that have a relationship with bone and tooth health, and planned a PubMed search, selecting micronutrients previously identified as MeSH (Medical Subject Headings) terms and adding to each of them the words "dental implants" and "osseointegration". The TEP identified 19 studies concerning vitamin D, magnesium, resveratrol, vitamin C, a mixture of calcium, magnesium, zinc, and vitamin D, and synthetic bone mineral. However, several micronutrients are non-authorized by the "EU Register on nutrition and health claims" for improving bone and/or tooth health. Our scoping review suggests a limited role of nutraceuticals in promoting osseointegration of dental implants, although, in some cases, such as for vitamin D deficiency, there is a clear link among their deficit, reduced osseointegration, and early implant failure, thus requiring an adequate supplementation.

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.

Icariin Promotes the Osteogenic Action of BMP2 by Activating the cAMP Signaling Pathway

Icariin (ICA) is the main active flavonoid glucoside from herbs of the genus Epimedium; in traditional Chinese medicine, these herbs have long been prescribed for the treatment of bone fractures and osteoporosis. Several studies have shown that treatment with ICA can increase osteogenic differentiation and reduce bone loss in vivo and in vitro. However, the definite signaling pathway of this osteogenic effect remains unclear. In this study, we selected bone morphogenetic protein 2 (BMP2)-induced osteoblastic differentiation of multipotent mesenchymal progenitor C2C12 cells as a model of osteoblast differentiation. We investigated the effects of ICA on C2C12 cells osteogenic differentiation and the underlying molecular mechanisms. We found that ICA could enhance BMP2-mediated osteoblastic differentiation of C2C12 cells in a dose-dependent manner. Treatment with ICA activated the cAMP/PKA/CREB signaling axis in a time-dependent manner. Blocking cAMP signaling using the PKA selective inhibitor H89 significantly inhibited the stimulatory effect of ICA on osteogenesis. Therefore, the osteoinductive potential and the low cost of ICA indicate that it is a promising alternative treatment or promoter for enhancing the therapeutic effects of BMP2.

Prior administration of vitamin K2 improves the therapeutic effects of zoledronic acid in ovariectomized rats by antagonizing zoledronic acid-induced inhibition of osteoblasts proliferation and mineralization

Zoledronic acid (ZA) exerts complex influence on bone by suppressing bone resorption, mostly due to the direct osteoclasts inhibition and uncertain influence on osteoblasts. Vitamin K₂ (VK₂, Menaquinone-4) as an anabolic agent stimulates bone formation via anti-apoptosis in osteoblasts and mild osteoclasts inhibition. Based on these knowledge, the therapeutic effect of the combined or sequential therapy of VK₂ and ZA depends on the influence on the osteoblasts, since both cases exert similar inhibitory effect on osteoclasts. In a series of in vitro studies, we confirmed the protective effect of VK₂ in osteoblasts culture, especially when followed by exposure to ZA, and the proliferation and mineralization inhibition induced by ZA towards osteoblasts. For mechanism study, expression of bcl-2/bax, Runx2 and Sost in cells were examined. For in vivo studies, an osteoporosis animal model was established in rats via ovariectomy (OVX) and subjected to sequential treatment, namely VK₂ followed by ZA. Bone mineral density (BMD) was measured by Dual energy X-ray absorptionmetry (DEXA), morphology and mechanical parameters by micro-computed tomography (micro-CT), mechanical strength by an electro-hydraulic fatigue-testing machine. The bone calcium, hydroxyproline content, blood lipids were evaluated using microplate technique, and the bone surface turnover was evaluated using the fluorescence in corporation method. It was found that VK₂ pretreatment partially prevented the inhibition of bone formation caused by ZA, which was reflected by indices like BMD, bone calcium content and bone strength. The underling mechanisms for protection of VK₂ pretreatment, mainly demonstrated via in vitro studies, included inhibiting apoptosis and depressing Sost expression in osteoblasts, which in turn improved the osteoporosis therapeutic effects of ZA. These findings suggested that pretreatment with VK₂ before ZA therapy might serve a new long-term therapy protocol for osteoporosis.

Vitamin K and Bone Metabolism: A Review of the Latest Evidence in Preclinical Studies

Bone is a metabolically active tissue that renews itself throughout one's life. Cytokines along with several hormonal, nutritional, and growth factors are involved in tightly regulated bone remodeling. Accordingly, vitamin K as a multifunctional vitamin has been recently deemed appreciable as a topic of research as it plays a pivotal role in maintenance of the bone strength, and it has been proved to have a positive impact on the bone metabolism. Vitamin K exerts its anabolic effect on the bone turnover in different ways such as promoting osteoblast differentiation, upregulating transcription of specific genes in osteoblasts, and activating the bone-associated vitamin k dependent proteins which play critical roles in extracellular bone matrix mineralization. There is also credible evidence to support the effects of vitamin k2 on differentiation of other mesenchymal stem cells into osteoblast. The main objective of the present paper is to comprehensively outline the preclinical studies on the properties of vitamin K and its effects on the bone metabolism. The evidence could shed light on further clinical studies to improve osteogenesis in bone graft surgeries.

Immunomodulatory effect of vitamin K2: Implications for bone health

OBJECTIVE

In women with postmenopausal osteoporosis, vitamin K2 appears to decrease the incidence of hip, vertebral, and non-vertebral fractures. Women with postmenopausal osteoporosis have more circulating activated T cells compared with healthy postmenopausal and premenopausal women, but the effects of vitamin K2 on T cells have not been studied. In this study, we have looked at T-cell suppression by vitamin K2.

MATERIALS AND METHODS

Peripheral blood mononuclear cells (PBMCs) from three healthy donors were used. The PBMCs were stimulated with the mitogens phytohemagglutinin and concanavalin A, and T-cell proliferation was analyzed using flow cytometry based on carboxyfluorescein succinimidyl ester (CSFE) dye dilution.

RESULTS

Vitamin K2 (60 and 100 μM) inhibited T-cell proliferation. Vitamin K1 at the same concentrations did not inhibit T-cell proliferation.

CONCLUSION

Vitamin K2 has immunomodulatory activities.

The effect of icariin on bone metabolism and its potential clinical application

Osteoporosis is a bone disease characterized by reduced bone mass, which leads to increased risk of bone fractures, and poses a significant risk to public health, especially in the elderly population. The traditional Chinese medicinal herb Epimedii has been utilized for centuries to treat bone fracture and bone loss. Icariin is a prenylated flavonol glycoside isolated from Epimedium herb, and has been shown to be the main bioactive component. This review provides a comprehensive survey of previous studies on icariin, including its structure and function, effect on bone metabolism, and potential for clinical application. These studies show that icariin promotes bone formation by stimulating osteogenic differentiation of BMSCs (bone marrow-derived mesenchymal stem cells), while inhibiting osteoclastogenic differentiation and the bone resorption activity of osteoclasts. Furthermore, icariin has been shown to be more potent than other flavonoid compounds in promoting osteogenic differentiation and maturation of osteoblasts. A 24-month randomized double-blind placebo-controlled clinical trial reported that icariin was effective in preventing postmenopausal osteoporosis with relatively low side effects. In conclusion, icariin may represent a class of flavonoids with bone-promoting activity, which could be used as potential treatment of postmenopausal osteoporosis.