A systematic review on the mechanisms of vitamin K effects on the complications of diabetes and pre-diabetes

Association Between Circulating Vitamin K Levels, Gut Microbiome, and Type 1 Diabetes: A Mendelian Randomization Study

BACKGROUND/OBJECTIVES

Nutritional deficiencies have been proposed as possible etiological causes for autoimmune diseases, among which type 1 diabetes (T1D). Vitamin K (VK) has potentially positive effects on type 2 diabetes, but its role on T1D in humans remains largely unknown. We aimed to examine the presence of a causal association between VK and T1D using a Mendelian randomization (MR) approach.

METHODS

Genetic variants from a genome-wide association study (GWAS) for VK (N = 2138 Europeans) were used as instruments in our two-sample MR study to investigate whether circulating VK levels are causally associated with the risk of T1D in a large European T1D GWAS cohort (18,942 cases/520,580 controls). Through a multivariable MR (MVMR), the effects of both VK and specific gut microbiota on T1D were investigated given that the gut microbiome synthesizes VK.

RESULTS

We found that changes in levels of circulating VK did not affect T1D risk in our univariate two-sample MR, but this study had limited power to detect small effects of VK (OR for T1D of less than 0.8). However, our MVMR indicated a suggestive association of VK with the risk of T1D adjusting for two different gut microbiome populations.

CONCLUSIONS

In conclusion, VK levels are unlikely to significantly affect the risk of T1D, but small effects cannot be excluded, and the role of gut microbiome in this association should be further investigated.

Efficacy and Safety of Direct Oral Anticoagulants Versus Warfarin in Patients With Atrial Fibrillation and Liver Cirrhosis

OBJECTIVE

Comparing direct oral anticoagulants (DOACs) and warfarin's efficacy and safety in patients with nonvalvular atrial fibrillation (AF) and liver cirrhosis (LC).

BACKGROUND

Evidence of the pharmacodynamics of DOACs is limited in patients with AF and LC.

METHODS

A retrospective cohort study was conducted in the largest hospital system in Taiwan, involving patients with AF and LC for the years 2012 to 2021. Hazards of thromboembolic events (ischemic stroke, transient ischemic attack, and systemic embolism), intracranial hemorrhage, gastrointestinal, major bleeding, and all-cause mortality were investigated with a new-user, active comparator design. Inverse probability of treatment weighting was applied to balance potential confounders between treatment groups.

RESULTS

In total, 478 DOAC users and 247 warfarin users were included. DOACs and warfarin demonstrated similar trends in preventing thromboembolic events, namely ischemic stroke [adjusted hazard ratio (aHR), 1.05 (95% CI: 0.42-2.61)], transient ischemic attack [aHR, 1.36 (95% CI: 0.18-10.31)], and systemic embolism [aHR, 0.49 (95% CI: 0.14-1.70)]. DOAC use was associated with a similar risk of intracranial hemorrhage [aHR, 0.65 (95% CI: 0.26-1.59)] and gastrointestinal bleeding [aHR, 0.64 (95% CI: 0.39-1.03)], a decreased risk of major bleeding [aHR, 0.64 (95% CI: 0.42-0.99)], and a reduction in mortality [aHR, 0.73 (95% CI: 0.54-0.99)]. DOAC users exhibited a significant reduction in major bleeding risk in patients with Child-Pugh class A (aHR, 0.48; 95% CI: 0.33-0.70).

CONCLUSIONS

DOACs showed potential safety advantages over warfarin for patients with nonvalvular AF and LC, particularly in reducing major bleeding risk in those with Child-Pugh class A.

The Impact of Amine-Functionalised Iron Oxide Nanoparticles on the Menaquinone-7 Isomer Profile and Production of the Bioactive Isomer

The K family of vitamins includes a collection of molecules with different pharmacokinetic characteristics. Menaquinone-7 (MK-7) has the finest properties and is the most therapeutically beneficial due to its long plasma half-life and outstanding extrahepatic bioavailability. MK-7 exhibits cis-trans isomerism, and merely the all-trans form is biologically efficacious. Therefore, the remedial value of MK-7 end products is exclusively governed by the quantity of all-trans MK-7. Consumers favour fermentation for the production of MK-7; however, it involves several challenges. The low MK-7 yield and extensive downstream processing requirements increase production costs, resulting in an expensive final product that is not universally available. Bacterial cell immobilisation with iron oxide nanoparticles (IONs) can potentially address the limitations of MK-7 fermentation. Uncoated IONs tend to have low stability and can adversely affect cell viability; thus, amine-functionalised IONs, owing to their increased physicochemical stability and biocompatibility, are a favourable alternative. Nonetheless, employing biocompatible IONs for this purpose is only advantageous if the bioactive MK-7 isomer is obtained in the most significant fraction, exploring which formed the aim of this investigation. Two amine-functionalised IONs, namely 3-aminopropyltriethoxysilane (APTES)-coated IONs (IONs@APTES) and L-Lysine (L-Lys)-coated IONs (L-Lys@IONs), were synthesised and characterised, and their impact on various parameters was evaluated. IONs@APTES were superior, and the optimal concentration (300 μ g/mL) increased all-trans MK-7 production and improved its yield relative to the untreated cells by 2.3- and 3.1-fold, respectively. The outcomes of this study present an opportunity to develop an innovative and effective fermentation method that enhances the production of bioactive MK-7.

The effect of vitamin K supplementation on cardiovascular risk factors: a systematic review and meta-analysis

Cardiovascular disease (CVD) is one of the most important diseases which controlling its related risk factors, such as metabolic and inflammatory biomarkers, is necessary because of the increased mortality risk of that. The aim of our meta-analysis is to reveal the general effect of vitamin K supplementation on its related risk factors. Original databases were searched using standard keywords to identify all randomized clinical trials (RCTs) investigating the effects of vitamin K on CVD. Pooled weighted mean difference (WMD) and 95 % confidence intervals (95 % CI) were achieved by random-model effect analysis for the best estimation of outcomes. The statistical heterogeneity was determined using the Cochran's Q test and I2 statistics. Seventeen studies were included in this systematic review and meta-analysis. The pooled findings showed that vitamin K supplementation can reduce homeostatic model assessment insulin resistance (HOMA-IR) (WMD: -0⋅24, 95 % CI: -0⋅49, -0⋅02, P = 0⋅047) significantly compared to the placebo group. However, no significant effect was observed on other outcomes. Subgroup analysis showed a significant effect of vitamin K2 supplementation compared to vitamin K1 supplementation on HOMA-IR. However, no significant effect was observed on other variables. Also, subgroup analysis showed no potential effect of vitamin K supplementation on any outcome and omitting any articles did not affect the final results. We demonstrated that supplementation with vitamin K has no effect on anthropometrics indexes, CRP, glucose metabolism, and lipid profile factors except HOMA-IR.

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

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

The effect of vitamin K4 supplementation on insulin resistance in individuals with type 2 diabetes: a double-blind randomised placebo-controlled clinical trial

PURPOSE

The purpose of this study was to assess the possible clinical effects of vitamin K4 supplementation in individuals with type 2 diabetes namely insulin resistance, glycaemic control, and lipid profile.

METHODS

This was a prospective randomised double-blind placebo-controlled clinical trial. A total of 106 patients were randomised to receive either 1 mg of vitamin K4 (menadiol diacetate) or placebo for 24 weeks.

RESULTS

Ninety patients (n = 45 in each study group) were included in the final analysis. After 24 weeks, homeostatic model assessment of insulin resistance (HOMA-IR) (16.54 ± 7.81 vs. 29.09 ± 36.56, P = 0.027) and fasting serum insulin (FSI) (6.86 ± 3.45 vs. 11.13 ± 12.66 µU/ml, P = 0.032) were significantly lower in the vitamin K group compared to placebo. Additionally, triglycerides (TG) (144.94 ± 50.7 vs. 172.8 ± 101.5 mg/dl, P = 0.031) and very low-density lipoproteins (VLDL) levels (28.9 ± 9.88 vs. 34.6 ± 20.30 mg/dl, P = 0.027) decreased significantly in the vitamin K group after 24 weeks compared to baseline. Moreover, more patients in the vitamin K group (35.6%) had their antidiabetic medication doses reduced after 24 weeks compared to placebo (13.3%, P = 0.029).

CONCLUSION

Vitamin K4 supplementation for 24 weeks is capable of improving insulin resistance and TG levels in individuals with type 2 diabetes. In addition, the improvement in insulin resistance was reflected in the decrease in antidiabetic medication doses. However, it did not affect fasting plasma glucose (FPG) or glycated haemoglobin (HbA1c).

TRIAL REGISTRATION

The study was registered on clinicaltrials.gov with ID: NCT04285450.

The impact of aging and oxidative stress in metabolic and nervous system disorders: programmed cell death and molecular signal transduction crosstalk

Life expectancy is increasing throughout the world and coincides with a rise in non-communicable diseases (NCDs), especially for metabolic disease that includes diabetes mellitus (DM) and neurodegenerative disorders. The debilitating effects of metabolic disorders influence the entire body and significantly affect the nervous system impacting greater than one billion people with disability in the peripheral nervous system as well as with cognitive loss, now the seventh leading cause of death worldwide. Metabolic disorders, such as DM, and neurologic disease remain a significant challenge for the treatment and care of individuals since present therapies may limit symptoms but do not halt overall disease progression. These clinical challenges to address the interplay between metabolic and neurodegenerative disorders warrant innovative strategies that can focus upon the underlying mechanisms of aging-related disorders, oxidative stress, cell senescence, and cell death. Programmed cell death pathways that involve autophagy, apoptosis, ferroptosis, and pyroptosis can play a critical role in metabolic and neurodegenerative disorders and oversee processes that include insulin resistance, β-cell function, mitochondrial integrity, reactive oxygen species release, and inflammatory cell activation. The silent mating type information regulation 2 homolog 1 (Saccharomyces cerevisiae) (SIRT1), AMP activated protein kinase (AMPK), and Wnt1 inducible signaling pathway protein 1 (WISP1) are novel targets that can oversee programmed cell death pathways tied to β-nicotinamide adenine dinucleotide (NAD+), nicotinamide, apolipoprotein E (APOE), severe acute respiratory syndrome (SARS-CoV-2) exposure with coronavirus disease 2019 (COVID-19), and trophic factors, such as erythropoietin (EPO). The pathways of programmed cell death, SIRT1, AMPK, and WISP1 offer exciting prospects for maintaining metabolic homeostasis and nervous system function that can be compromised during aging-related disorders and lead to cognitive impairment, but these pathways have dual roles in determining the ultimate fate of cells and organ systems that warrant thoughtful insight into complex autofeedback mechanisms.

The Interaction of Dietary Patterns and Genetic Variants on the Risk of Cardiovascular Diseases in Chinese Patients with Type 2 Diabetes

SCOPE

Diabetes is an important risk factor for cardiovascular disease (CVD), which in turn is the most common and serious complication of diabetes. This study analyzes dietary patterns and single nucleotide polymorphisms (SNPs) in 543 diabetes patients with new-onset cardiovascular events and 461 diabetic patients without.

METHODS AND RESULTS

SNPs are determined and analyzed using real time PCR and gene chip method. Factor analysis and logistic regression are used to determine dietary patterns and evaluate the level of associations and interaction effects, respectively. The legumes and edible fungi pattern and vegetable pattern show a significant negative correlation with complication risk. ADIPOQ rs37563 and legumes and edible fungi pattern have a significant interactive effect on disease, and patients with a high score of C polymorphism genotype (GC + CC) have a lower risk of disease. 5-10-Methylenetetrahydrofolate reductase (MTHFR) rs1801131 and vegetable pattern have a borderline interaction effect on disease, and those patients with TT genotype have a lower risk of disease.

CONCLUSION

These findings provide new insights into the role of the interactive protection of dietary patterns and SNPs. And participants with specific alleles show a lower risk of cardiovascular complications.

Vitamin K - a scoping review for Nordic Nutrition Recommendations 2023

Vitamin K occurs in dietary supply in two major forms: phylloquinone (vitamin K1) and menaquinones (collectively referred as vitamin K2). Phylloquinone is derived from plants. There are at least 10 forms of menaquinones varying in chain length and they are produced by bacteria except menaquinone-4. Menaquinone-4 is formed from phylloquinone or other menaquinone forms. Phylloquinone is considered to be the major contributor and menaquinones are thought to contribute less to vitamin K intake in Western diets. However, less is known about the content of menaquinones than phylloquinones in foods. Vitamin K is known to function as an enzymatic cofactor in the gamma-carboxylation of vitamin K dependent proteins (VKDPs). Hepatic VKDPs are involved in coagulation. Extrahepatic VKDPs have a role e.g. in bone health and vascular calcification. However, the amount of vitamin K needed for optimal functioning of the different VKDPs is not known.

Vitamin K1 Intake and Incident Diabetes in the Danish Diet, Cancer, and Health Study

CONTEXT

Observational studies have reported lower risks of type 2 diabetes with higher vitamin K1 intake, but these studies overlook effect modification due to known diabetes risk factors.

OBJECTIVE

To identify subgroups that might benefit from vitamin K1 intake, we examined associations between vitamin K1 intake and incident diabetes overall and in subpopulations at risk of diabetes.

METHODS

Participants from the prospective cohort, the Danish Diet, Cancer, and Health Study, with no history of diabetes were followed up for diabetes incidence. The association between intake of vitamin K1, estimated from a food frequency questionnaire completed at baseline, and incident diabetes was determined using multivariable-adjusted Cox proportional-hazards models.

RESULTS

In 54 787 Danish residents with a median (interquartile range) age of 56 (52-60) years at baseline, 6700 individuals were diagnosed with diabetes during 20.8 (17.3-21.6) years of follow-up. Vitamin K1 intake was inversely and linearly associated with incident diabetes (P < .0001). Compared to participants with the lowest vitamin K1 intake (median:57 µg/d), participants with the highest intakes (median:191 µg/d) had a 31% lower risk of diabetes (HR; 95% CI, 0.69; 0.64-0.74) after multivariable adjustments. The inverse association between vitamin K1 intake and incident diabetes was present in all subgroups (namely, men and women, ever and never smokers, low and high physical activity groups, and in participants who were normal to overweight and obese), with differences in absolute risk between subgroups.

CONCLUSION

Higher intake of foods rich in vitamin K1 was associated with a lower risk of diabetes. If the associations observed are causal, our results indicate that more cases of diabetes would be prevented in subgroups at higher risk (men, smokers, participants with obesity, and those with low physical activity).

Oral anticoagulation across diabetic subtypes in patients with newly diagnosed atrial fibrillation: A report from the GARFIELD-AF registry

AIMS

This study aims to describe both management and prognosis of patients with diabetes mellitus (DM) and newly diagnosed atrial fibrillation (AF), overall as well as by antidiabetic treatment, and to assess the influence of oral anticoagulation (OAC) on outcomes by DM status.

METHODS

The study population comprised 52 010 newly diagnosed patients with AF, 11 542 DM and 40 468 non-DM, enrolled in the GARFIELD-AF registry. Follow-up was truncated at 2 years after enrolment. Comparative effectiveness of OAC versus no OAC was assessed by DM status using a propensity score overlap weighting scheme and weights were applied to Cox models.

RESULTS

Patients with DM [39.3% oral antidiabetic drug (OAD), 13.4% insulin ± OAD, 47.2% on no antidiabetic drug] had higher risk profile, OAC use, and rates of clinical outcomes compared with patients without DM. OAC use was associated in patients without DM and patients with DM with lower risk of all-cause mortality [hazard ratio 0.75 (0.69-0.83), 0.74 (0.64-0.86), respectively] and stroke/systemic embolism (SE) [0.69 (0.58-0.83), 0.70 (0.53-0.93), respectively]. The risk of major bleeding with OAC was similarly increased in patients without DM and those with DM [1.40 (1.14-1.71), 1.37 (0.99-1.89), respectively]. Patients with insulin-requiring DM had a higher risk of all-cause mortality and stroke/SE [1.91 (1.63-2.24)], [1.57 (1.06-2.35), respectively] compared with patients without DM, and experienced significant risk reductions of all-cause mortality and stroke/SE with OAC [0.73 (0.53-0.99); 0.50 (0.26-0.97), respectively].

CONCLUSIONS

In both patients with DM and patients without DM with AF, OAC was associated with lower risk of all-cause mortality and stroke/SE. Patients with insulin-requiring DM derived significant benefit from OAC.

Does Vitamin K2 Influence the Interplay between Diabetes Mellitus and Intervertebral Disc Degeneration in a Rat Model?

Intervertebral disc (IVD) degeneration is a common cause of low back pain in diabetes mellitus type 2 (T2DM) patients. Its pathogenesis and the vitamin (vit.) K2 influence on this disease remain unclear. Lumbar motion segments of male Zucker Diabetes Fatty (ZDF) rats (non-diabetic [control] and diabetic; fed without or with vit. K2) were used. Femur lengths and vertebral epiphyseal cross-section areas were measured. IVDs were histopathologically examined. Protein synthesis and gene expression of isolated IVD fibrochondrocytes were analyzed. T2DM rats showed histopathological IVD degeneration. Femur lengths and epiphyseal areas were smaller in T2DM rats regardless of vit. K2 feeding. Fibrochondrocytes synthesized interleukin (IL)-24 and IL-10 with no major differences between groups. Alpha smooth muscle actin (αSMA) was strongly expressed, especially in cells of vit. K2-treated animals. Gene expression of aggrecan was low, and that of collagen type 2 was high in IVD cells of diabetic animals, whether treated with vit. K2 or not. Suppressor of cytokine signaling (Socs)3 and heme oxygenase (Hmox)1 gene expression was highest in the cells of diabetic animals treated with vit. K2. Vit. K2 influenced the expression of some stress-associated markers in IVD cells of diabetic rats, but not that of IL-10 and IL-24.

The Effect of Iron Oxide Nanoparticles on the Menaquinone-7 Isomer Composition and Synthesis of the Biologically Significant All-Trans Isomer

Menaquinone-7 (MK-7) is the most therapeutically valuable K vitamin owing to its excellent bioavailability. MK-7 occurs as geometric isomers, and only all-trans MK-7 is bioactive. The fermentation-based synthesis of MK-7 entails various challenges, primarily the low fermentation yield and numerous downstream processing steps. This raises the cost of production and translates to an expensive final product that is not widely accessible. Iron oxide nanoparticles (IONPs) can potentially overcome these obstacles due to their ability to enhance fermentation productivity and enable process intensification. Nevertheless, utilisation of IONPs in this regard is only beneficial if the biologically active isomer is achieved in the greatest proportion, the investigation of which constituted the objective of this study. IONPs (Fe₃O₄) with an average size of 11 nm were synthesised and characterised using different analytical techniques, and their effect on isomer production and bacterial growth was assessed. The optimum IONP concentration (300 μg/mL) improved the process output and resulted in a 1.6-fold increase in the all-trans isomer yield compared to the control. This investigation was the first to evaluate the role of IONPs in the synthesis of MK-7 isomers, and its outcomes will assist the development of an efficient fermentation system that favours the production of bioactive MK-7.

Risk of heart failure in elderly patients with atrial fibrillation and diabetes taking different oral anticoagulants: a nationwide cohort study

BACKGROUND

Heart failure (HF) is a critical complication in elderly patients with atrial fibrillation (AF) and diabetes mellitus (DM). Recent preclinical studies suggested that non-vitamin K antagonist oral anticoagulants (NOACs) can potentially suppress the progression of cardiac fibrosis and ischemic cardiomyopathy. Whether different oral anticoagulants influence the risk of HF in older adults with AF and DM is unknown. This study aimed to evaluate the risk of HF in elderly patients with AF and DM who were administered NOACs or warfarin.

METHODS

A nationwide retrospective cohort study was conducted based on claims data from the entire Taiwanese population. Target trial emulation design was applied to strengthen causal inference using observational data. Patients aged  ≥ 65 years with AF and DM on NOAC or warfarin treatment between 2012 and 2019 were included and followed up until 2020. The primary outcome was newly diagnosed HF. Propensity score-based fine stratification weightings were used to balance patient characteristics between NOAC and warfarin groups. Hazard ratios (HRs) were estimated using Cox proportional hazard models.

RESULTS

The study included a total of 24,835 individuals (19,710 NOAC and 5,125 warfarin users). Patients taking NOACs had a significantly lower risk of HF than those taking warfarin (HR = 0.80, 95% CI 0.74-0.86, p < 0.001). Subgroup analyses for individual NOACs suggested that dabigatran (HR = 0.86, 95% CI 0.80-0.93, p < 0.001), rivaroxaban (HR = 0.80, 95% CI 0.74-0.86, p < 0.001), apixaban (HR = 0.78, 95% CI 0.68-0.90, p < 0.001), and edoxaban (HR = 0.72, 95% CI 0.60-0.86, p < 0.001) were associated with lower risks of HF than warfarin. The findings were consistent regardless of age and sex subgroups and were more prominent in those with high medication possession ratios. Several sensitivity analyses further supported the robustness of our findings.

CONCLUSIONS

This nationwide cohort study demonstrated that elderly patients with AF and DM taking NOACs had a lower risk of incident HF than those taking warfarin. Our findings suggested that NOACs may be the preferred oral anticoagulant treatment when considering the prevention of heart failure in this vulnerable population. Future research is warranted to elucidate causation and investigate the underlying mechanisms.

Dysbiosis in Patients with Chronic Kidney Disease: Let Us Talk About Vitamin K

PURPOSE OF REVIEW

This narrative review aimed to summarize the current evidence on the connection between dysbiosis and vitamin K deficiency in patients with chronic kidney disease (CKD). The presence of dysbiosis (perturbations in the composition of the microbiota) has been described in several non-communicable diseases, including chronic kidney disease, and it has been hypothesized that dysbiosis may cause vitamin K deficiency. Patients with CKD present both vitamin K deficiency and gut dysbiosis; however, the relationship between gut dysbiosis and vitamin K deficiency remains to be addressed.

RECENT FINDINGS

Recently, few studies in animals have demonstrated that a dysbiotic environment is associated with low production of vitamin K by the gut microbiota. Vitamin K plays a vital role in blood coagulation as well as in the cardiovascular and bone systems. It serves as a cofactor for γ-glutamyl carboxylases and thus is essential for the post-translational modification and activation of vitamin K-dependent calcification regulators, such as osteocalcin, matrix Gla protein, Gla-rich protein, and proteins C and S. Additionally, vitamin K executes essential antioxidant and anti-inflammatory functions. Dietary intake is the main source of vitamin K; however, it also can be produced by gut microbiota. This review discusses the effects of uremia on the imbalance in gut microbiota, vitamin K-producing bacteria, and vitamin K deficiency in CKD patients, leading to a better understanding and raising hypothesis for future clinical studies.

Optimisation of the fermentation media to enhance the production of the bioactive isomer of vitamin menaquinone-7

Menaquinone-7 (MK-7) offers significant health benefits; however, only the all-trans form is biologically active. MK-7 produced through fermentation can occur as all-trans and cis isomers, and the therapeutic value of the resulting MK-7 is exclusively determined by the quantity of the all-trans isomer. Therefore, this study aimed to investigate the effect of the media composition on the isomer profile obtained from fermentation and determine the optimum media combination to increase the concentration of the all-trans isomer and diminish the production of cis MK-7. For this purpose, design of experiments (DOE) was used to screen the most effective nutrients, and a central composite face-centred design (CCF) was employed to optimise the media components. The optimum media consisted of 1% (w/v) glucose, 2% (w/v) yeast extract, 2% (w/v) soy peptone, 2% (w/v) tryptone, and 0.1% (w/v) CaCl2. This composition resulted in an average all-trans and cis isomer concentration of 36.366 mg/L and 1.225 mg/L, respectively. In addition, the optimised media enabled an all-trans isomer concentration 12.2-fold greater and a cis isomer concentration 2.9-fold less than the unoptimised media. This study was the first to consider the development of an optimised fermentation media to enhance the production of the bioactive isomer of MK-7 and minimise the concentration of the inactive isomer. Furthermore, this media is commercially promising, as it will improve the process productivity and reduce the costs associated with the industrial fermentation of the vitamin.

Beneficial effects of non-herbal supplements on patients with diabetes

BACKGROUND AND AIMS

Controlling glycemic levels is crucial for patients with diabetes mellitus to improve their disease management and health outcomes. Beyond lifestyle modification and pharmacotherapy, some supplements have been shown to lower blood glucose as well as mitigate diabetic complications.

METHODS

Information was primarily gathered by employing various PubMed scholarly articles for real-world examples in addition to data extraction from supplementary manuscripts. Only original human trials were used, and those published within the past two decades were primarily chosen. However, background information may contains review articles.

RESULTS

Some non-herbal supplements have been suggested to lower fasting blood glucose, postprandial glucose, glycated glucose (HbA1c), lipid profiles, oxidative stress, and inflammation, as well as improving body composition, insulin sensitivity, blood pressure, and nephropathy.

CONCLUSION

This review discusses ten non-herbal supplements that have been reported to have beneficial effects among different types of patients with diabetes as well as potential future clinical application. However, more long-term studies with a larger amount and more diverse participants need to be conducted for a robust conclusion. Also, mechanisms of action of antidiabetic effects are poorly understood and need further research.

Is the Risk of Diabetes Lower in Patients With Atrial Fibrillation Treated With Direct Oral Anticoagulant Compared to Warfarin?

Background

The use of anticoagulants is an established strategy to prevent stroke, embolism, and cardiovascular mortality in patients with atrial fibrillation (AF), but its role in the prevention of incident diabetes is unclear. We aimed to investigate this question by using participant data from cohort studies.

Methods

We conducted a meta-analysis of participants to investigate the impact of direct oral anticoagulants (DOACs) on the risk of new-onset diabetes in AF patients. The collection of related data was performed in the PubMed and EMBASE databases until December 2021, including studies associated with evaluating the correlation between DOACs and incident diabetes. The hazard ratios (HRs) and 95% confidence intervals (CIs) were adjusted by the random-effects model with an inverse variance method.

Results

Two cohort studies with a total of 24,434 patients were included in this study (warfarin: n = 6,906; DOACs: n = 17,528). Compared with warfarin, the use of DOACs could reduce the incident diabetic risk in AF patients (HR = 0.75, 95%CI: 0.68–0.82). Investigations about the effects of three major classes of DOACs showed that the individual use of dabigatran (HR = 0.76, 95%CI: 0.64–0.90), rivaroxaban (HR = 0.74, 95%CI: 0.64–0.87), apixaban (HR = 0.74, 95%CI: 0.60–0.92) and the combined use of rivaroxaban and apixaban (HR = 0.74, 95%CI: 0.66–0.84) could reduce the risk of new-onset diabetes compared with warfarin. This risk reduction effect could be observed in both male and female groups (HR = 0.73, 95%CI: 0.64–0.84, P &lt; 0.00001; HR = 0.82, 95%CI: 0.82–0.99, P = 0.04).

Conclusions

Treatment with DOACs compared with warfarin reduced the risk of new-onset diabetes in both male and female patients with AF.

Estimation of Vitamin K Content and Its Sources in the Diet of the Polish Participants of the PURE Study

The aim of the study was to estimate the content of K1, K2 (MK-n) as well as total K vitamins and their sources in the diets of 1985 PURE Poland study participants based on the FFQ questionnaire. Due to the pleiotropic effect of K vitamins, it is important to know their food sources depending on different eating habits. Total vitamin K in the diets amounted to 331.1 ± 151.5 µg/d and 358.6 ± 181.0 µg/d for men and women, respectively. Dietary patterns (DPs) were identified in the study group, and the relationship between them and vitamin K intake was assessed. The proportion of dominant products as sources of vitamin K in the fourth quartile of each of the three identified DPs did not change significantly compared to the proportion of these products as sources of vitamin K in all subjects. In the fourth quartile of individual DPs, vitamin K1 came mainly from vegetables (56.5-76.8%); K2 mainly from processed meat and high-fat cheese and cream (70.1-77.6%); and total K mainly from vegetables and processed meat (57.6-67.8%). Intakes of K vitamins were high and similar in terms of predominant vitamin K provider products, in groups of subjects whose diets were most consistent with the particular DP. In the absence of global findings on the most appropriate dietary content of MK-n vitamins other than phylloquinone, the estimated high content of these vitamins in the diets of the subjects compared with other nations suggests that their level in diets was satisfactory. Future studies should aim to determine the need for MK-n vitamins in terms of fulfilling all their functions in the body.

The effect of menaquinone-7 supplementation on dp-ucMGP, PIVKAII, inflammatory markers, and body composition in type 2 diabetes patients: a randomized clinical trial

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a common disorder that is characterized by chronic hyperglycemia and chronic inflammation, which also have a reinforcing effect on each other. The present research studied the effects of menaquinone (MK-7) supplementation on serum dp-ucMGP (dephospho uncarboxylated Matrix Gla Protein), PIVKAII (Prothrombin Induced by Vitamin K Absence), inflammatory markers and body composition indices in type 2 diabetes mellitus (T2DM) patients.

METHODS

This 12-week double-blind placebo-controlled randomized clinical trial allocated 60 T2DM patients equally into a MK-7 (200 mcg/day) group or a placebo group. All patients also received dietary advice at the beginning of study and their dietary intakes were checked using a 3-day food record. The body composition of each patient was also measured and their vitamin K status was assessed using the ELISA method to measure serum dp-ucMGP and PIVKAII. In addition, inflammatory status indices were also measured, including hsCRP (high-sensitivity C-reactive protein), IL-6 (interleukin-6) and TNF-α (tumor necrosis factor alpha). All measurements were made both before and after the intervention period.

RESULTS

In total 45 patients completed the trial (MK-7 group = 23 and placebo group = 22). The calorie and macronutrient intake of the two groups were similar pre and post intervention. There were statistically significant increases in dietary vitamin K intake for both groups over the course of the study (p < 0.05), but the intergroup differences were not significant. The body composition indices (i.e., body fat percentage, fat mass, fat free mass, muscle mass, bone mass and total body water) were not significantly different between groups or across the trial. The serum levels of the vitamin K markers, PIVKAII and dp-ucMGP, decreased significantly in the MK-7 group over the course of the study (p < 0.05), but there was no decrease in the placebo group. However, after adjusting for the baseline levels and changes in vitamin K intake, the between group differences were only significant for PIVKAII (p < 0.05). Following the intervention, the serum levels of the inflammatory markers (hsCRP, IL-6, and TNF-α) were significantly lower in the MK-7 group (p < 0.05), but not in the placebo group. However, the between group differences in the inflammatory markers were not statistically significant.

CONCLUSIONS

Although further studies are needed, it appears that MK-7 supplementation can be effective in improving PIVKAII levels, but not for improving dp-ucMGP, inflammatory status or the body composition indices of T2DM patients.

TRIAL REGISTRATION NUMBER

This study was prospectively registered at the Iranian Registry of Clinical Trials on the 20th of May 2019 (ID: IRCT20100123003140N22).

Diabetes-Related Complications and Mortality in Patients With Atrial Fibrillation Receiving Different Oral Anticoagulants : A Nationwide Analysis

BACKGROUND

Evidence about the association between types of oral anticoagulants and hazards of diabetes complications is limited in patients with atrial fibrillation (AF) and diabetes mellitus (DM).

OBJECTIVE

To compare the hazards of diabetes complications and mortality between patients with AF and DM receiving non-vitamin K antagonist oral anticoagulants (NOACs) and those receiving warfarin.

DESIGN

A retrospective cohort study.

SETTING

Nationwide data obtained from Taiwan's National Health Insurance Research Database.

PATIENTS

Patients with AF and DM receiving NOACs or warfarin between 2012 and 2017 in Taiwan were enrolled. Treatment groups were determined by patients' first initiation of oral anticoagulants.

MEASUREMENTS

Hazards of diabetes complications (macrovascular complications, microvascular complications, and glycemic emergency) and mortality in the NOAC and warfarin users were investigated with a target trial design. Cause-specific Cox proportional hazards models were used to estimate hazard ratios (HRs). Propensity score methods with stabilized inverse probability of treatment weighting were applied to balance potential confounders between treatment groups.

RESULTS

In total, 19 909 NOAC users and 10 300 warfarin users were included. Patients receiving NOACs had significantly lower hazards of developing macrovascular complications (HR, 0.84 [95% CI, 0.78 to 0.91]; P < 0.001), microvascular complications (HR, 0.79 [CI, 0.73 to 0.85]; P < 0.001), glycemic emergency (HR, 0.91 [CI, 0.83 to 0.99]; P = 0.043), and mortality (HR, 0.78 [CI, 0.75 to 0.82]; P < 0.001) than those receiving warfarin. Analyses with propensity score matching showed similar results. Several sensitivity analyses further supported the robustness of our findings.

LIMITATION

The claims-based data did not allow for detailed data on patients' lifestyles and laboratory examinations to be obtained.

CONCLUSION

Non-vitamin K antagonist oral anticoagulants were associated with lower hazards of diabetes complications and mortality than warfarin in patients with AF and DM.

PRIMARY FUNDING SOURCE

Hualien Tzu Chi Hospital.

Vitamin K: A vital micronutrient with the cardioprotective potential against diabetes-associated complications

Cardiovascular disease (CVD) remains the leading cause of mortality in patients with type 2 diabetes (T2D). The conventional therapies seem to offer minimal long-term cardioprotection against diabetes-related complications in patients living with T2D. There is a growing interest in understanding the therapeutic effects of food-derived bioactive compounds in protecting or managing these metabolic diseases. This includes uncovering the therapeutic potential of fat-soluble micronutrients such as vitamin K, which are abundantly found in green leafy vegetables. We searched the major electronic databases including PubMed, Web of Sciences, Scopus, Google Scholar and Science direct. The search retrieved randomized clinical trials and preclinical studies, reporting on the impact of vitamin K on CVD-related complications in T2D. The current review updates clinical evidence on the therapeutic benefits of vitamin K by attenuating CVD-risk factors such as blood lipid profiles, blood pressure, as well as markers of oxidative stress and inflammation in patients with T2D. Importantly, the summarized preclinical evidence provides a unique perspective into the pathophysiological mechanisms that could be targeted by vitamin K in the primary prevention of T2D-related complications. Lastly, this review further explores the controversies related to the cardioprotective effects of vitamin K, and also provides the basic information such as the source and bioavailability profile of this micronutrient is covered to highlight its therapeutic potential.

The Role of Vitamin K in Humans: Implication in Aging and Age-Associated Diseases

As human life expectancy is rising, the incidence of age-associated diseases will also increase. Scientific evidence has revealed that healthy diets, including good fats, vitamins, minerals, or polyphenolics, could have antioxidant and anti-inflammatory activities, with antiaging effects. Recent studies demonstrated that vitamin K is a vital cofactor in activating several proteins, which act against age-related syndromes. Thus, vitamin K can carboxylate osteocalcin (a protein capable of transporting and fixing calcium in bone), activate matrix Gla protein (an inhibitor of vascular calcification and cardiovascular events) and carboxylate Gas6 protein (involved in brain physiology and a cognitive decline and neurodegenerative disease inhibitor). By improving insulin sensitivity, vitamin K lowers diabetes risk. It also exerts antiproliferative, proapoptotic, autophagic effects and has been associated with a reduced risk of cancer. Recent research shows that protein S, another vitamin K-dependent protein, can prevent the cytokine storm observed in COVID-19 cases. The reduced activation of protein S due to the pneumonia-induced vitamin K depletion was correlated with higher thrombogenicity and possibly fatal outcomes in COVID-19 patients. Our review aimed to present the latest scientific evidence about vitamin K and its role in preventing age-associated diseases and/or improving the effectiveness of medical treatments in mature adults ˃50 years old.

Risk of developing diabetes in patients with atrial fibrillation taking non-vitamin K antagonist oral anticoagulants or warfarin: A nationwide cohort study

AIM

To compare the risk of diabetes development in patients with atrial fibrillation (AF) treated with non-vitamin K antagonist oral anticoagulants (NOACs) and warfarin.

MATERIALS AND METHODS

We conducted a nationwide retrospective cohort study using Taiwan's National Health Insurance Research Database. Adult patients with new onset of AF, treated with NOACs or warfarin between 2012 and 2016, were included. The NOAC cohort was further divided into dabigatran, rivaroxaban and apixaban groups. The primary outcome was incident diabetes requiring treatment with antidiabetic drugs. Fine and Gray subdistribution hazards models were used to estimate the adjusted hazard ratio (aHR). Propensity score matching was performed for each head-to-head comparison.

RESULTS

A total of 10 746 new-onset AF patients were included in our study. During the mean 2.4-year follow-up, NOACs were associated with a lower risk of developing diabetes than warfarin (aHR = 0.80, 95% confidence interval [CI]: 0.68-0.94, P = .007). Subgroup analyses confirmed that dabigatran, rivaroxaban and apixaban each had a reduced diabetes risk. Stratified analyses showed that the lower risk of diabetes associated with NOAC treatment was specific to patients aged 65 years or older (aHR = 0.74, 95% CI: 0.62-0.89, P = .002) and those with good medication adherence (aHR = 0.70, 95% CI: 0.58-0.84, P < .001).

CONCLUSIONS

Taking an NOAC was associated with a lower risk of developing diabetes than taking warfarin in patients with AF.

Glycemic control improvement in individuals with type 2 diabetes with vitamin K2 supplementation: a randomized controlled trial

PURPOSE

This study aimed to investigate the effects of vitamin K₂ supplementation in the form of menaquinone-7 (MK-7) on glucose, insulin, and lipid metabolism in patients with type 2 diabetes mellitus (T2DM).

METHODS

In this double-blinded, placebo-controlled, randomized trial, 68 insulin-independent people with diabetes received either 180 µg MK-7 twice a day or placebo for 12 weeks. We assessed fasting plasma glucose (FPG) and insulin concentrations (primary outcomes), glycated hemoglobin (HbA1c), insulin sensitivity indices, and lipid profiles (secondary outcomes) at baseline and end of the trial.

RESULTS

At the end of the trial, FPG (effect size (ES) = - 0.68; p-adjusted = 0.031) and HbA1c (ES = - 0.36; p-adjusted = 0.004) were significantly lower in the vitamin K₂ group compared with the placebo at the end of the trial. The number of participants achieved the target levels of glycemic control based on FPG, and HbA1c concentrations were significantly higher in the vitamin K₂ group compared to the placebo group. Insulin concentrations (ES = - 0.29; p = 0.019) and homeostatic model assessment for insulin resistance (HOMA-IR) significantly decreased in the vitamin K₂ group (ES = - 0.29; p = 0.019) compared to baseline, but their values were not significantly different compared to the placebo group at the end of the trial. No significant variation was observed in lipid profiles.

CONCLUSION

Daily intake of 360 µg Vitamin K₂ in the form of MK-7 for 12-weeks reduces FPG and HbA1c in patients with T2DM but does not have a lipid-lowering effect.

Synthesis of Naphthoquinone Derivatives: Menaquinones, Lipoquinones and Other Vitamin K Derivatives

Menaquinones are a class of isoprenoid molecules that have important roles in human biology and bacterial electron transport, and multiple methods have been developed for their synthesis. These compounds consist of a methylnaphthoquinone (MK) unit and an isoprene side chain, such as found in vitamin K₁ (phylloquinone), K₂, and other lipoquinones. The most common naturally occurring menaquinones contain multiple isoprene units and are very hydrophobic, rendering it difficult to evaluate the biological activity of these compounds in aqueous assays. One way to overcome this challenge has been the application of truncated MK-derivatives for their moderate solubility in water. The synthesis of such derivatives has been dominated by Friedel-Crafts alkylation with BF₃∙OEt₂. This attractive method occurs over two steps from commercially available starting materials, but it generally produces low yields and a mixture of isomers. In this review, we summarize reported syntheses of both truncated and naturally occurring MK-derivatives that encompass five different synthetic strategies: Nucleophilic ring methods, metal-mediated reactions, electrophilic ring methods, pericyclic reactions, and homologation and side chain extensions. The advantages and disadvantages of each method are discussed, identifying methods with a focus on high yields, regioselectivity, and stereochemistry leading to a detailed overview of the reported chemistry available for preparation of these compounds.

Traditional plain yogurt: a therapeutic food for metabolic syndrome?

Dairy products have an important role in a healthy diet due to their high-quality protein and rich micronutrients. Yogurt, a fermented milk product, has a similar composition to milk but is a more concentrated product in terms of group B vitamins, minerals, and proteins. It is known that bioactive metabolites and live enzymes that occur by fermentation and digestion, affect the health positively by improving gut microbiota. In recent years, the prevalence of metabolic syndrome, which threatens public health, is increasing rapidly. As with other noninfectious diseases, the diet has an important effect on the prevention and treatment of metabolic syndrome. It has been demonstrated that yogurt has a high-quality amino acid pattern, reduces energy intake by stimulating satiety, and regulates blood glucose level. In addition to the rich protein variety, yogurt also contains peptides that positively affect blood pressure. Unlike milk, increased acidity during the fermentation of yogurt positively affects calcium absorption. Calcium plays an important role in the control of blood glucose and energy metabolism through insulin-dependent and non-insulin-dependent routes. In addition to reducing inflammation, calcium has a positive effect on the regulation of the blood lipid profile by increasing fecal fat excretion. There are many lipid and lipoid nutrients such as saturated fatty acids, phospholipids, sphingolipids, and conjugated linoleic acid that may affect the blood lipid profile in yogurt positively or negatively. There are seen very few randomized controlled studies that are focused on the relationship between yogurt and metabolic syndrome, and these are based on contradictory results. In this review, based on the clinical studies conducted to date, and the nutrient content of yogurt, possible mechanisms of these contradictory results are investigated.

New Insights for nicotinamide: Metabolic disease, autophagy, and mTOR

Metabolic disorders, such as diabetes mellitus (DM), are increasingly becoming significant risk factors for the health of the global population and consume substantial portions of the gross domestic product of all nations. Although conventional therapies that include early diagnosis, nutritional modification of diet, and pharmacological treatments may limit disease progression, tight serum glucose control cannot prevent the onset of future disease complications. With these concerns, novel strategies for the treatment of metabolic disorders that involve the vitamin nicotinamide, the mechanistic target of rapamycin (mTOR), mTOR Complex 1 (mTORC1), mTOR Complex 2 (mTORC2), AMP activated protein kinase (AMPK), and the cellular pathways of autophagy and apoptosis offer exceptional promise to provide new avenues of treatment. Oversight of these pathways can promote cellular energy homeostasis, maintain mitochondrial function, improve glucose utilization, and preserve pancreatic beta-cell function. Yet, the interplay among mTOR, AMPK, and autophagy pathways can be complex and affect desired clinical outcomes, necessitating further investigations to provide efficacious treatment strategies for metabolic dysfunction and DM.

Effects of MK-7 Supplementation on Glycemic Status, Anthropometric Indices and Lipid Profile in Patients with Type 2 Diabetes: A Randomized Controlled Trial

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a prevalent disorder which accounts for 90-95% of diabetic patients. The aim of this study was to assess the effects of menaquinone (MK-7) supplementation on glycemic indices, anthropometric indices and lipid profile, among patients with T2DM.

METHODS

In this double-blind placebo-controlled randomized clinical trial, 60 men and women with T2DM were allocated equally into either the MK-7 (200 µg/day) or the placebo group. Physical activity level and dietary intake were assessed using the international physical activity questionnaire-short form (IPAQ-SF) and a 3-day food record, pre- and post-intervention. Anthropometric measures, blood pressure, glycemic indices and lipid profile including fasting blood sugar (FBS), hemoglobin A1c (HBA1C), fasting insulin (FI), homeostatic model assessment insulin resistance index (HOMA-IR), triglycerides (TG), total cholesterol (TC), high-density lipoprotein (HDL-C) and low-density lipoprotein (LDL-C) were measured at baseline and after twelve weeks.

RESULTS

Forty-five patients completed the trial. There were no significant between-group differences for calorie intake, macronutrient intake, physical activity level or anthropometric measures at baseline and at the end of the study. Dietary vitamin K intake increased significantly at the end of the study in the MK-7 (p: 0.02) and placebo (p: 0.001) groups, but intergroup differences were not significant (p: 0.86). FBS (p: 0.01), HbA1c (p: 0.002), fasting insulin (p: 0.01) and HOMA-IR (p: 0.007) decreased significantly in the MK-7 group. Furthermore, after adjustment for the baseline values and changes of vitamin K intake at the end of study, FBS and HbA1C showed significant intergroup changes, and they were significantly lower in the MK-7 group compared to the placebo group. Lipid profile (TG, TC, LDL-C, HDL-C and LDL-C/HDL-C) did not change significantly within or between groups.

CONCLUSION

MK-7 supplementation seems to be effective in the improvement of glycemic indices, but not the lipid profile of patients with T2DM.

CLINICAL TRIAL REGISTRATION

The present study was prospectively registered at the Iranian Registry of Clinical Trials on May 2019 (ID: IRCT20100123003140N22).