Unveiling cellular and molecular aspects of ascending thoracic aortic aneurysms and dissections.

Ascending thoracic aortic aneurysm (ATAA) remains a significant medical concern, with its asymptomatic nature posing diagnostic and monitoring challenges, thereby increasing the risk of aortic wall dissection and rupture. Current management of aortic repair relies on an aortic diameter threshold. However, this approach underestimates the complexity of aortic wall disease due to important knowledge gaps in understanding its underlying pathologic mechanisms.Since traditional risk factors cannot explain the initiation and progression of ATAA leading to dissection, local vascular factors such as extracellular matrix (ECM) and vascular smooth muscle cells (VSMCs) might harbor targets for early diagnosis and intervention. Derived from diverse embryonic lineages, VSMCs exhibit varied responses to genetic abnormalities that regulate their contractility. The transition of VSMCs into different phenotypes is an adaptive response to stress stimuli such as hemodynamic changes resulting from cardiovascular disease, aging, lifestyle, and genetic predisposition. Upon longer exposure to stress stimuli, VSMC phenotypic switching can instigate pathologic remodeling that contributes to the pathogenesis of ATAA.This review aims to illuminate the current understanding of cellular and molecular characteristics associated with ATAA and dissection, emphasizing the need for a more nuanced comprehension of the impaired ECM-VSMC network.

Effect of vitamin K supplementation on serum calcification propensity and arterial stiffness in vitamin K-deficient kidney transplant recipients: A double-blind, randomized, placebo-controlled clinical trial.

Vitamin K deficiency is common among kidney transplant recipients (KTRs) and likely contributes to progressive vascular calcification and stiffness. In this single-center, randomized, double-blind, placebo-controlled trial, we aimed to investigate the effects of vitamin K supplementation on the primary end point, serum calcification propensity (calciprotein particle maturation time, T50), and secondary end points arterial stiffness (pulse wave velocity [PWV]) and vitamin K status in 40 vitamin K-deficient KTRs (plasma dephosphorylated uncarboxylated matrix Gla protein [dp-ucMGP] ≥500 pmol/L). Participants (35% female; age, 57 ± 13 years) were randomized 1:1 to vitamin K2 (menaquinone-7, 360 µg/day) or placebo for 12 weeks. Vitamin K supplementation had no effect on calcification propensity (change in T50 vs baseline +2.3 ± 27.4 minutes) compared with placebo (+0.8 ± 34.4 minutes; Pbetween group = .88) but prevented progression of PWV (change vs baseline -0.06 ± 0.26 m/s) compared with placebo (+0.27 ± 0.43 m/s; Pbetween group = .010). Vitamin K supplementation strongly improved vitamin K status (change in dp-ucMGP vs baseline -385 [-631 to -269] pmol/L) compared with placebo (+39 [-188 to +183] pmol/L; Pbetween group < .001), although most patients remained vitamin K-deficient. In conclusion, vitamin K supplementation did not alter serum calcification propensity but prevented progression of arterial stiffness, suggesting that vitamin K has vascular effects independent of calciprotein particles. These results set the stage for longer-term intervention studies with vitamin K supplementation in KTRs. TRIAL REGISTRY: EU Clinical Trials Register (EudraCT Number: 2019-004906-88) and the Dutch Trial Register (NTR number: NL7687).

γ-Glutamyl carboxylase mutations differentially affect the biological function of vitamin K-dependent proteins.

γ-Glutamyl carboxylase (GGCX) is an integral membrane protein that catalyzes posttranslational carboxylation of a number of vitamin K-dependent (VKD) proteins involved in a wide variety of physiologic processes, including blood coagulation, vascular calcification, and bone metabolism. Naturally occurring GGCX mutations are associated with multiple distinct clinical phenotypes. However, the genotype-phenotype correlation of GGCX remains elusive. Here, we systematically examined the effect of all naturally occurring GGCX mutations on the carboxylation of 3 structure-function distinct VKD proteins in a cellular environment. GGCX mutations were transiently introduced into GGCX-deficient human embryonic kidney 293 cells stably expressing chimeric coagulation factor, matrix Gla protein (MGP), or osteocalcin as VKD reporter proteins, and then the carboxylation efficiency of these reporter proteins was evaluated. Our results show that GGCX mutations differentially affect the carboxylation of these reporter proteins and the efficiency of using vitamin K as a cofactor. Carboxylation of these reporter proteins by a C-terminal truncation mutation (R704X) implies that GGCX's C terminus plays a critical role in the binding of osteocalcin but not in the binding of coagulation factors and MGP. This has been confirmed by probing the protein-protein interaction between GGCX and its protein substrates in live cells using bimolecular fluorescence complementation and chemical cross-linking assays. Additionally, using a minigene splicing assay, we demonstrated that several GGCX missense mutations affect GGCX's pre-messenger RNA splicing rather than altering the corresponding amino acid residues. Results from this study interpreted the correlation of GGCX's genotype and its clinical phenotypes and clarified why vitamin K administration rectified bleeding disorders but not nonbleeding disorders.

Inhibition of Neutral Sphingomyelinase 2 by Novel Small Molecule Inhibitors Results in Decreased Release of Extracellular Vesicles by Vascular Smooth Muscle Cells and Attenuated Calcification.

Vascular calcification (VC) is an important contributor and prognostic factor in the pathogenesis of cardiovascular diseases. VC is an active process mediated by the release of extracellular vesicles by vascular smooth muscle cells (VSMCs), and the enzyme neutral sphingomyelinase 2 (nSMase2 or SMPD3) plays a key role. Upon activation, the enzyme catalyzes the hydrolysis of sphingomyelin, thereby generating ceramide and phosphocholine. This conversion mediates the release of exosomes, a type of extracellular vesicles (EVs), which ultimately forms the nidus for VC. nSMase2 therefore represents a drug target, the inhibition of which is thought to prevent or halt VC progression. In search of novel druglike small molecule inhibitors of nSMase2, we have used virtual ligand screening to identify potential ligands. From an in-silico collection of 48,6844 small druglike molecules, we selected 996 compounds after application of an in-house multi-step procedure combining different filtering and docking procedures. Selected compounds were functionally tested in vitro; from this, we identified 52 individual hit molecules that inhibited nSMase2 activity by more than 20% at a concentration of 150 µM. Further analysis showed that five compounds presented with IC50s lower than 2 µM. Of these, compounds ID 5728450 and ID 4011505 decreased human primary VSMC EV release and calcification in vitro. The hit molecules identified here represent new classes of nSMase2 inhibitors that may be developed into lead molecules for the therapeutic or prophylactic treatment of VC.

Dietary magnesium supplementation inhibits abdominal vascular calcification in an experimental animal model of chronic kidney disease.

BACKGROUND: Vascular calcification is a key process involved in cardiovascular morbidity and mortality in patients with chronic kidney disease (CKD). Magnesium supplementation may counteract vascular calcification. In this study we aimed to determine whether increased dietary magnesium intake inhibits vascular calcification in CKD in vivo and explore the mechanisms underlying these effects. METHODS: Sprague Dawley rats were partially nephrectomized and fed a diet with high phosphate and either high or normal magnesium content for 16 weeks. The primary outcome was the tissue calcium content of the aorta in the high versus normal dietary magnesium group. In addition, we analysed plasma mineral concentrations, aortic vascular calcification identified with von Kossa staining, calcium apposition time and aortic expression of genes related to vascular calcification. RESULTS: The number of animals in the highest tissue calcium content tertile was significantly lower in the abdominal aorta [1 (10%) versus 6 (55%); P = .03] in the high versus normal dietary magnesium group, but did not differ in the aortic arch and thoracic aorta. Von Kossa staining and calcium apposition time corresponded to these results. The median tissue calcium content was not significantly different between the groups. Serum phosphate concentrations and expression of osteogenic markers in the aorta did not differ between the groups. CONCLUSIONS: This study demonstrates that increased dietary magnesium inhibits abdominal vascular calcification in an experimental animal model of CKD in vivo. These are promising results for CKD patients and further study is needed to identify the mechanisms involved and to determine the clinical relevance in patients.

Combining phosphate binder therapy with vitamin K2 inhibits vascular calcification in an experimental animal model of kidney failure.

BACKGROUND: Hyperphosphataemia is strongly associated with cardiovascular disease and mortality. Recently, phosphate binders (PBs), which are used to bind intestinal phosphate, have been shown to bind vitamin K, thereby potentially aggravating vitamin K deficiency. This vitamin K binding by PBs may offset the beneficial effects of phosphate reduction in reducing vascular calcification (VC). Here we assessed whether combining PBs with vitamin K2 supplementation inhibits VC. METHODS: We performed 3/4 nephrectomy in rats, after which warfarin was given for 3 weeks to induce vitamin K deficiency. Next, animals were fed a high phosphate diet in the presence of low or high vitamin K2 and were randomized to either control or one of four different PBs for 8 weeks. The primary outcome was the amount of thoracic and abdominal aorta VC measured by high-resolution micro-computed tomography (µCT). Vitamin K status was measured by plasma MK7 levels and immunohistochemically analysed in vasculature using uncarboxylated matrix Gla protein (ucMGP) specific antibodies. RESULTS: The combination of a high vitamin K2 diet and PB treatment significantly reduced VC as measured by µCT for both the thoracic (P = 0.026) and abdominal aorta (P = 0.023), compared with MK7 or PB treatment alone. UcMGP stain was significantly more present in the low vitamin K2-treated groups in both the thoracic (P < 0.01) and abdominal aorta (P < 0.01) as compared with high vitamin K2-treated groups. Moreover, a high vitamin K diet and PBs led to reduced vascular oxidative stress. CONCLUSION: In an animal model of kidney failure with vitamin K deficiency, neither PB therapy nor vitamin K2 supplementation alone prevented VC. However, the combination of high vitamin K2 with PB treatment significantly attenuated VC.

Endoplasmic Reticulum Stress Mediates Vascular Smooth Muscle Cell Calcification via Increased Release of Grp78 (Glucose-Regulated Protein, 78 kDa)-Loaded Extracellular Vesicles.

OBJECTIVE: Vascular calcification is common among aging populations and mediated by vascular smooth muscle cells (VSMCs). The endoplasmic reticulum (ER) is involved in protein folding and ER stress has been implicated in bone mineralization. The role of ER stress in VSMC-mediated calcification is less clear. Approach and Results: mRNA expression of the ER stress markers PERK (PKR (protein kinase RNA)-like ER kinase), ATF (activating transcription factor) 4, ATF6, and Grp78 (glucose-regulated protein, 78 kDa) was detectable in human vessels with levels of PERK decreased in calcified plaques compared to healthy vessels. Protein deposition of Grp78/Grp94 was increased in the matrix of calcified arteries. Induction of ER stress accelerated human primary VSMC-mediated calcification, elevated expression of some osteogenic markers (Runx2 [RUNX family transcription factor 2], OSX [Osterix], ALP [alkaline phosphatse], BSP [bone sialoprotein], and OPG [osteoprotegerin]), and decreased expression of SMC markers. ER stress potentiated extracellular vesicle (EV) release via SMPD3 (sphingomyelin phosphodiesterase 3). EVs from ER stress-treated VSMCs showed increased Grp78 levels and calcification. Electron microscopy confirmed the presence of Grp78/Grp94 in EVs. siRNA (short interfering RNA) knock-down of Grp78 decreased calcification. Warfarin-induced Grp78 and ATF4 expression in rat aortas and VSMCs and increased calcification in an ER stress-dependent manner via increased EV release. CONCLUSIONS: ER stress induces vascular calcification by increasing release of Grp78-loaded EVs. Our results reveal a novel mechanism of action of warfarin, involving increased EV release via the PERK-ATF4 pathway, contributing to calcification. This study is the first to show that warfarin induces ER stress and to link ER stress to cargo loading of EVs.

Differential Effects of Platelet Factor 4 (CXCL4) and Its Non-Allelic Variant (CXCL4L1) on Cultured Human Vascular Smooth Muscle Cells.

Platelet factor 4 (CXCL4) is a chemokine abundantly stored in platelets. Upon injury and during atherosclerosis, CXCL4 is transported through the vessel wall where it modulates the function of vascular smooth muscle cells (VSMCs) by affecting proliferation, migration, gene expression and cytokine release. Variant CXCL4L1 is distinct from CXCL4 in function and expression pattern, despite a minor three-amino acid difference. Here, the effects of CXCL4 and CXCL4L1 on the phenotype and function of human VSMCs were compared in vitro. VSMCs were found to constitutively express CXCL4L1 and only exogenously added CXCL4 was internalized by VSMCs. Pre-treatment with heparin completely blocked CXCL4 uptake. A role of the putative CXCL4 receptors CXCR3 and DARC in endocytosis was excluded, but LDL receptor family members appeared to be involved in the uptake of CXCL4. Incubation of VSMCs with both CXCL4 and CXCL4L1 resulted in decreased expression of contractile marker genes and increased mRNA levels of KLF4 and NLRP3 transcription factors, yet only CXCL4 stimulated proliferation and calcification of VSMCs. In conclusion, CXCL4 and CXCL4L1 both modulate gene expression, yet only CXCL4 increases the division rate and formation of calcium-phosphate crystals in VSMCs. CXCL4 and CXCL4L1 may play distinct roles during vascular remodeling in which CXCL4 induces proliferation and calcification while endogenously expressed CXCL4L1 governs cellular homeostasis. The latter notion remains a subject for future investigation.

Calcium Signalling in Heart and Vessels: Role of Calmodulin and Downstream Calmodulin-Dependent Protein Kinases.

Cardiovascular disease is the major cause of death worldwide. The success of medication and other preventive measures introduced in the last century have not yet halted the epidemic of cardiovascular disease. Although the molecular mechanisms of the pathophysiology of the heart and vessels have been extensively studied, the burden of ischemic cardiovascular conditions has risen to become a top cause of morbidity and mortality. Calcium has important functions in the cardiovascular system. Calcium is involved in the mechanism of excitation-contraction coupling that regulates numerous events, ranging from the production of action potentials to the contraction of cardiomyocytes and vascular smooth muscle cells. Both in the heart and vessels, the rise of intracellular calcium is sensed by calmodulin, a protein that regulates and activates downstream kinases involved in regulating calcium signalling. Among them is the calcium calmodulin kinase family, which is involved in the regulation of cardiac functions. In this review, we present the current literature regarding the role of calcium/calmodulin pathways in the heart and vessels with the aim to summarize our mechanistic understanding of this process and to open novel avenues for research.

Reduced Vitamin K Status as a Potentially Modifiable Risk Factor of Severe Coronavirus Disease 2019.

BACKGROUND: Respiratory failure and thromboembolism are frequent in severe acute respiratory syndrome coronavirus 2-infected patients. Vitamin K activates both hepatic coagulation factors and extrahepatic endothelial anticoagulant protein S, required for thrombosis prevention. In times of vitamin K insufficiency, hepatic procoagulant factors are preferentially activated over extrahepatic proteins. Vitamin K also activates matrix Gla protein (MGP), which protects against pulmonary and vascular elastic fiber damage. We hypothesized that vitamin K may be implicated in coronavirus disease 2019 (COVID-19), linking pulmonary and thromboembolic disease. METHODS: A total of 135 hospitalized COVID-19 patients were compared with 184 historic controls. Inactive vitamin K-dependent MGP (desphospho-uncarboxylated [dp-uc] MGP) and prothrombin (PIVKA-II) were measured inversely related to extrahepatic and hepatic vitamin K status, respectively. Desmosine was measured to quantify the rate of elastic fiber degradation. Arterial calcification severity was assessed using computed tomography. RESULTS: dp-ucMGP was elevated in COVID-19 patients compared with controls (P < .001), with even higher dp-ucMGP in patients with poor outcomes (P < .001). PIVKA-II was normal in 82.1% of patients. dp-ucMGP was correlated with desmosine (P < .001) and with coronary artery (P = .002) and thoracic aortic (P < .001) calcification scores. CONCLUSIONS: dp-ucMGP was severely increased in COVID-19 patients, indicating extrahepatic vitamin K insufficiency, which was related to poor outcome; hepatic procoagulant factor II remained unaffected. These data suggest pneumonia-induced extrahepatic vitamin K depletion leading to accelerated elastic fiber damage and thrombosis in severe COVID-19 due to impaired activation of MGP and endothelial protein S, respectively.

Vitamin K and cardiovascular complications in chronic kidney disease patients.

Vitamin K, well known for its role in coagulation, encompasses 2 major subgroups: vitamin K1 is exclusively synthesized by plants, whereas vitamin K2 mostly originates from bacterial synthesis. Vitamin K serves as a cofactor for the enzyme γ-glutamyl carboxylase, which carboxylates and thereby activates various vitamin K-dependent proteins. Several vitamin K-dependent proteins are synthesized in bone, but the role of vitamin K for bone health in chronic kidney disease patients, in particular the prevention of osteoporosis, is still not firmly established. Herein, we focus on another prominent action of vitamin K, in particular vitamin K2 (namely, the activation of matrix γ-carboxyglutamic acid protein, the most potent inhibitor of cardiovascular calcifications). Multiple observational studies link relative vitamin K deficiency or low intake to cardiovascular calcification progress, morbidity, and mortality. Patients with advanced chronic kidney disease are particularly vitamin K deficient, in part because of dietary restrictions but possibly also due to impaired endogenous recycling of vitamin K. At the same time, this population is characterized by markedly accelerated cardiovascular calcifications and mortality. High-dose dietary supplementation with vitamin K2, in particular the most potent form, menaquinone 7, can potently reduce circulating levels of dephosphorylated uncarboxylated (i.e., inactive matrix γ-carboxyglutamic acid protein) in patients with end-stage kidney disease. However, despite this compelling data basis, several randomized controlled trials with high-dose menaquinone 7 supplements in patients with advanced chronic kidney disease have failed to confirm cardiovascular benefits. Herein, we discuss potential reasons and solutions for this.

Functional vitamin K status and risk of incident chronic kidney disease and microalbuminuria: a prospective general population-based cohort study.

BACKGROUND: Circulating desphospho-uncarboxylated matrix γ-carboxyglutamate (Gla) protein (dp-ucMGP), a marker of vitamin K status, is associated with renal function and may serve as a potentially modifiable risk factor for incident chronic kidney disease (CKD). We aimed to assess the association between circulating dp-ucMGP and incident CKD. METHODS: We included 3969 participants with a mean age of 52.3 ± 11.6 years, of whom 48.0% were male, enrolled in the general population-based Prevention of REnal and Vascular ENd-stage Disease study. Study outcomes were incident CKD, defined as either development of an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 or microalbuminuria. Associations of dp-ucMGP with these outcomes were quantified using Cox proportional hazards models and were adjusted for potential confounders. RESULTS: Median plasma dp-ucMGP was 363 [interquartile range (IQR) 219-532] pmol/L and mean serum creatinine- and serum cystatin C-based eGFR (eGFRSCr-SCys) was 95.4 ± 21.8 mL/min/1.73 m2. During 7.1 years of follow-up, 205 (5.4%) participants developed incident CKD and 303 (8.4%) developed microalbuminuria. For every doubling of plasma dp-ucMGP, hazard ratios for the development of incident CKD and microalbuminuria were 1.85 [95% confidence interval (CI) 1.59-2.16; P < 0.001] and 1.19 (95% CI 1.07-1.32; P = 0.001), respectively. These associations lost significance after adjustment for baseline eGFRSCr-SCys [0.99 (95% CI 0.88-1.12; P = 0.86)] and baseline age [1.03 (95% CI 0.94-1.14; P = 0.50)], respectively. CONCLUSIONS: The associations of plasma dp-ucMGP with incident CKD and microalbuminuria were driven by the respective baseline effects of renal function and age.

Combined low vitamin D and K status amplifies mortality risk: a prospective study.

OBJECTIVE: To explore the association of both plasma vitamin D and K concentrations with all-cause mortality, cardiovascular mortality, and cardiovascular events in the general population. METHODS: We studied 4742 participants of the Prevention of REnal and Vascular ENd-Stage Disease (PREVEND) Study. At baseline, vitamin D and K status was determined by measurement of 25-hydroxyvitamin D [25(OH)D] and dephosphorylated uncarboxylated matrix Gla protein (dp-ucMGP), respectively. Patients were categorized into: 25(OH)D < 50 or ≥ 50 nmol/L and dp-ucMGP < 361 or ≥ 361 pmol/L with 25(OH)D > 75 nmol/L and dp-ucMGP < 361 pmol/L as reference. Cause of death was coded according to International Classification of Diseases 9&10 codes from the 2001-2003 examination until date of death/event or censoring date (January 1st, 2017). RESULTS: Mean age was 52.6 ± 11.9 years and 2513 (53%) were female. During a median of 14.2 year follow-up, 620 participants died of which 142 were due to cardiovascular causes. Combined low vitamin D and K status was present in 970 participants (20%) and was associated with a greater risk of all-cause mortality compared to high vitamin D and high vitamin K status group (n = 1424) after adjusting for potential confounders: hazard ratio 1.46 (95% confidence intervals 1.12-1.90). We observed similar trends, albeit non-significant for cardiovascular mortality, and cardiovascular events: 1.42 (0.79-2.55), 1.28 (0.93-1.77), respectively. CONCLUSIONS: Combined low vitamin D and K status are associated with increased all-cause mortality risk and possibly with cardiovascular mortality and cardiovascular events compared with adequate vitamin D and K status. Future studies should investigate the effect of combined vitamin D and K supplementation on clinical outcomes.

Early vascular ageing in chronic kidney disease: impact of inflammation, vitamin K, senescence and genomic damage.

Chronic kidney disease (CKD) is a clinical model of premature ageing characterized by cardiovascular disease, persistent uraemic inflammation, osteoporosis muscle wasting and frailty. The accelerated early vascular ageing (EVA) process mediated by medial vascular calcification (VC) is a hallmark of senescence as well as a strong predictor of cardiovascular morbidity and mortality in the CKD population. Current clinical therapeutic strategies and novel treatments for VC have not yet been proven to prevent or reverse VC progression in patients with CKD. Knowledge of the fundamental mechanism underlying EVA is urgently needed to identify and develop novel and efficient therapeutic targets for VC and EVA. An accumulating body of evidence indicates that deoxyribonucleic acid (DNA) damage-induced cellular senescence and 'inflammaging' may largely contribute to such pathological conditions characterized by accelerated EVA. Growing evidence shows that nuclear factor erythroid 2-related factor 2 (NRF2) signalling and vitamin K play a crucial role in counteracting oxidative stress, DNA damage, senescence and inflammaging, whereby NRF2 activation and vitamin K supplementation may provide a novel treatment target for EVA. In this review we discuss the link between senescence and EVA in the context of CKD, with a focus on the role of NRF2 and vitamin K in DNA damage signalling, senescence and inflammaging.

Target identification for the diagnosis and intervention of vulnerable atherosclerotic plaques beyond 18F-fluorodeoxyglucose positron emission tomography imaging: promising tracers on the horizon.

Cardiovascular disease is the major cause of morbidity and mortality in developed countries and atherosclerosis is the major cause of cardiovascular disease. Atherosclerotic lesions obstruct blood flow in the arterial vessel wall and can rupture leading to the formation of occlusive thrombi. Conventional diagnostic tools are still of limited value for identifying the vulnerable arterial plaque and for predicting its risk of rupture and of releasing thromboembolic material. Knowledge of the molecular and biological processes implicated in the process of atherosclerosis will advance the development of imaging probes to differentiate the vulnerable plaque. The development of imaging probes with high sensitivity and specificity in identifying high-risk atherosclerotic vessel wall changes and plaques is crucial for improving knowledge-based decisions and tailored individual interventions. Arterial PET imaging with 18F-FDG has shown promising results in identifying inflammatory vessel wall changes in numerous studies and clinical trials. However, due to its limited specificity in general and its intense physiological uptake in the left ventricular myocardium that impair imaging of the coronary arteries, different PET tracers for the molecular imaging of atherosclerosis have been evaluated. This review describes biological, chemical and medical expertise supporting a translational approach that will enable the development of new or the evaluation of existing PET tracers for the identification of vulnerable atherosclerotic plaques for better risk prediction and benefit to patients.

A Combination of Tamarindus indica seeds and Curcuma longa Rhizome Extracts Improves Knee Joint Function and Alleviates Pain in Non-Arthritic Adults Following Physical Activity.

Background: Knee joint pain is the most common reason for physical disability which associates with age. TamaFlexTM (NXT15906F6) is a synergistic anti-inflammatory formulation which contains ethanol/aqueous extracts of Tamarindus indica seeds and ethanol extract of Curcuma longa rhizome. Methods: In a 90-day randomized, double-blind, placebo-controlled study, we evaluated efficacy of NXT15906F6 in relieving pain and improving joint function in non-arthritic adults. Ninety non-arthritic subjects who experienced knee pain and joint discomfort following a six-minute walk test (SMWT) and Stair climb test (SCT) participated in the present trial. Subjects received either 250 mg (n=30) or 400 mg (n=30) of NXT15906F6 or matched placebo (PL: n=30) daily for 90 days. Improvement from baseline six-minute walk distance (SMWD) in NXT15906F6 groups, compared with placebo (PL) was the primary outcome of the study. Results: At post-intervention, subjects in NXT15906F6-250 (p<0.001) and NXT15906F6-400 (p<0.0001) groups showed substantial improvements in mean changes of SMWD from baseline compared to placebo. The 250 mg and 400 mg NXT15906F6 groups also improved average walking speed from baseline by 0.08±0.07 m/s (p=0.0010) and 0.11±0.08 m/s (p<0.0001), respectively. The NXT15906F6 groups experienced significant improvement in SMWT performances as early as 14 days. NXT15906F6-supplemented participants showed a consistent benefit of pain relief and improved musculoskeletal functions, compared to placebo. Conclusion: NXT15906F6 provided substantial relief from knee pain after physical activity and improved joint function in non-arthritic adults. Study participants did not show any major adverse events, and they tolerated well this novel herbal formulation.

Influence of pH and phosphate concentration on the phosphate binding capacity of five contemporary binders. An in vitro study.

AIM: Hyperphosphataemia is associated with increased mortality and morbidity in end stage renal disease. Despite phosphate binder therapy, a large proportion of patients do not reach the treatment target. In five contemporary binders we explored the influence of pH and phosphate concentration on phosphate binding. This interaction could be of relevance in clinical practice. METHODS: Phosphate binding was quantified in vitro in 25 mL of purified water containing phosphate concentrations of 10, 15 and 20 mM and baseline pH values of 3.0 or 6.0, with a binder over 6 h. Lanthanum carbonate, calcium acetate/magnesium carbonate, sevelamer carbonate, calcium carbonate and sucroferric oxyhydroxide, 67 mg of each, were used. The experiments were performed in duplicate. The primary outcome was the difference in the amount of bound phosphate for each binder after 6 h in solutions at two different pH values. Secondary outcomes were the influence of phosphate concentration on phosphate binding, next to binding patterns and phosphate binder saturation. RESULTS AND CONCLUSION: In this specific in vitro setting, lanthanum carbonate, sevelamer carbonate, calcium carbonate and sucroferric oxyhydroxide bound more phosphate in the solution with baseline pH of 3.0. Differences however were small except for lanthanum carbonate. Calcium acetate/magnesium carbonate was most effective in a solution with baseline pH of 6.0. All phosphate binders bound more phosphate in solutions with higher concentrations of phosphate. Sevelamer carbonate, calcium acetate/magnesium carbonate and sucroferric oxyhydroxide bound most phosphate in the first hour and reached maximum binding capacity in less than 6 h.

Calcific aortic valve stenosis: hard disease in the heart: A biomolecular approach towards diagnosis and treatment.

Calcific aortic valve stenosis (CAVS) is common in the ageing population and set to become an increasing economic and health burden. Once present, it inevitably progresses and has a poor prognosis in symptomatic patients. No medical therapies are proven to be effective in holding or reducing disease progression. Therefore, aortic valve replacement remains the only available treatment option. Improved knowledge of the mechanisms underlying disease progression has provided us with insights that CAVS is not a passive disease. Rather, CAVS is regulated by numerous mechanisms with a key role for calcification. Aortic valve calcification (AVC) is actively regulated involving cellular and humoral factors that may offer targets for diagnosis and intervention. The discovery that the vitamin K-dependent proteins are involved in the inhibition of AVC has boosted our mechanistic understanding of this process and has opened up novel avenues in disease exploration. This review discusses processes involved in CAVS progression, with an emphasis on recent insights into calcification, methods for imaging calcification activity, and potential therapeutic options.

Prothrombin Loading of Vascular Smooth Muscle Cell-Derived Exosomes Regulates Coagulation and Calcification.

OBJECTIVE: The drug warfarin blocks carboxylation of vitamin K-dependent proteins and acts as an anticoagulant and an accelerant of vascular calcification. The calcification inhibitor MGP (matrix Gla [carboxyglutamic acid] protein), produced by vascular smooth muscle cells (VSMCs), is a key target of warfarin action in promoting calcification; however, it remains unclear whether proteins in the coagulation cascade also play a role in calcification. APPROACH AND RESULTS: Vascular calcification is initiated by exosomes, and proteomic analysis revealed that VSMC exosomes are loaded with Gla-containing coagulation factors: IX and X, PT (prothrombin), and proteins C and S. Tracing of Alexa488-labeled PT showed that exosome loading occurs by direct binding to externalized phosphatidylserine (PS) on the exosomal surface and by endocytosis and recycling via late endosomes/multivesicular bodies. Notably, the PT Gla domain and a synthetic Gla domain peptide inhibited exosome-mediated VSMC calcification by preventing nucleation site formation on the exosomal surface. PT was deposited in the calcified vasculature, and there was a negative correlation between vascular calcification and the levels of circulating PT. In addition, we found that VSMC exosomes induced thrombogenesis in a tissue factor-dependent and PS-dependent manner. CONCLUSIONS: Gamma-carboxylated coagulation proteins are potent inhibitors of vascular calcification suggesting warfarin action on these factors also contributes to accelerated calcification in patients receiving this drug. VSMC exosomes link calcification and coagulation acting as novel activators of the extrinsic coagulation pathway and inducers of calcification in the absence of Gla-containing inhibitors.

Renal matrix Gla protein expression increases progressively with CKD and predicts renal outcome.

BACKGROUND: Matrix Gla Protein (MGP) is a potent inhibitor of ectopic calcification and modulates bone morphogenesis. Little is known about MGP expression or function in kidney. METHODS: We investigated renal MGP expression in Sprague-Dawley rats after 5/6 nephrectomy (5/6 Nx) and in human kidney biopsies in the Nephrotic Syndrome Study Network (NEPTUNE) cohort. We analyzed associations between glomerular (n = 182) and tubulointerstitial (TI) (n = 219) MGP mRNA levels and the disease activity/histologic features in NEPTUNE patients. Additionally, uncarboxylated and carboxylated MGP (ucMGP and cMGP, respectively) were localized by immunohistochemistry and quantitated in kidney tissues of patients at different stages of CKD (n = 18). RESULTS: Renal MGP expression was increased in rats after 5/6 Nx. In NEPTUNE data, baseline estimated glomerular filtration rate (eGFR) negatively correlated with glomerular and TI MGP expression (p <0.001). TI MGP expression strongly correlated with interstitial fibrosis, tubular atrophy, acute tubular injury, and interstitial inflammation, independent of eGFR. Kaplan-Meier analysis and multivariable Cox regression showed that higher levels of TI MGP expression were associated with an increased risk for the composite of 40% decline in eGFR and end-stage renal disease (ESRD) (HR, 3.31; 95% CI, 1.31 to 6.32; p =0.02). Glomerular and tubulointerstitial cells demonstrated nuclear and cytoplasmic cMGP and ucMGP staining, and eGFR inversely correlated with quantified glomerular cMGP staining (p <0.05). CONCLUSIONS: Our data demonstrate that renal MGP expression is increased in human and experimental CKD, and is associated with renal outcome. Additional studies are needed to determine its mechanism of action.