Increased Dephospho-uncarboxylated Matrix Gla-Protein Is Associated With Lower Axial Skeletal Muscle Mass in Patients With Hypertension.

BACKGROUND: Matrix Gla-protein (MGP) is a well-established inhibitor of vascular calcification that is activated by vitamin K-dependent carboxylation. In the setting of vitamin K2 deficiency, dephospho-uncarboxylated MGP (dpucMGP) levels increase, and have been associated with large artery stiffening. Vitamin K2 is also a mitochondrial electron carrier in muscle, but the relationship of vitamin K2 deficiency and dpucMGP with muscle mass is not well understood. We therefore aimed to examine the association of vitamin K2 deficiency and dpucMGP with skeletal muscle mass in patients with hypertension. METHODS: We studied 155 hypertensive adults without heart failure. Axial skeletal muscle mass was measured using magnetic resonance imaging from axial steady-state free precession images. DpucMGP was measured with ELISA. Carotid-femoral pulse wave velocity (CF-PWV) was measured from high-fidelity arterial tonometry recordings. RESULTS: We found an inverse relationship between dpucMGP levels and axial muscle mass, with progressively rising dpucMGP levels correlating with decreasing axial muscle mass. In an unadjusted linear regression model, correlates of dpucMGP included axial skeletal muscle area factor (ß = -0.32; P < 0.0001) and CF-PWV (ß = 0.31; P = 0.0008). In adjusted analyses, independent correlates of dpucMGP included axial skeletal muscle area factor (ß = -0.30; P = 0.0003) and CF-PWV (ß = 0.20; P = 0.019). CONCLUSIONS: In hypertensive adults, dpucMGP is independently associated with lower axial muscle mass, in addition to increased large artery stiffness. Further studies are required to investigate the role of vitamin K supplementation in this population.

The effect of dietary nitrate on exercise capacity in chronic kidney disease: a randomized controlled pilot study.

BACKGROUND: Chronic Kidney Disease (CKD) patients exhibit a reduced exercise capacity that impacts quality of life. Dietary nitrate supplementation has been shown to have favorable effects on exercise capacity in disease populations by reducing the oxygen cost of exercise. This study investigated whether dietary nitrates would acutely improve exercise capacity in CKD patients. METHODS AND RESULTS: In this randomized, double-blinded crossover study, 12 Stage 3-4 CKD patients (Mean ± SEM: Age, 60 ± 5yrs; eGFR, 50.3 ± 4.6 ml/min/1.73 m2) received an acute dose of 12.6 mmol of dietary nitrate in the form of concentrated beetroot juice (BRJ) and a nitrate depleted placebo (PLA). Skeletal muscle mitochondrial oxidative function was assessed using near-infrared spectroscopy. Cardiopulmonary exercise testing was performed on a cycle ergometer, with intensity increased by 25 W every 3 min until volitional fatigue. Plasma nitric oxide (NO) metabolites (NOm; nitrate, nitrite, low molecular weight S-nitrosothiols, and metal bound NO) were determined by gas-phase chemiluminescence. Plasma NOm values were significantly increased following BRJ (BRJ vs. PLA: 1074.4 ± 120.4 µM vs. 28.4 ± 6.6 µM, p < 0.001). Total work performed (44.4 ± 10.6 vs 39.6 ± 9.9 kJ, p = 0.03) and total exercise time (674 ± 85 vs 627 ± 86s, p = 0.04) were significantly greater following BRJ. Oxygen consumption at the ventilatory threshold was also improved by BRJ (0.90 ± 0.08 vs. 0.74 ± 0.06 L/min, p = 0.04). These changes occurred in the absence of improved skeletal muscle mitochondrial oxidative capacity (p = 0.52) and VO2peak (p = 0.35). CONCLUSIONS: Our findings demonstrate that inorganic nitrate can acutely improve exercise capacity in CKD patients. The effects of chronic nitrate supplementation on CKD related exercise intolerance should be investigated in future studies.

Vitamin K Status, Warfarin Use, and Arterial Stiffness in Heart Failure.

Large artery stiffening contributes to the pathophysiology of heart failure (HF) and associated comorbidities. MGP (matrix Gla-protein) is a potent inhibitor of vascular calcification. MGP activation is vitamin K-dependent. We aimed (1) to compare dp-ucMGP (dephospho-uncarboxylated MGP) levels between subjects with HF with preserved ejection fraction (HFpEF) and HF with reduced ejection fraction (HFrEF) and subjects without HF; (2) to assess the relationship between dp-ucMGP levels and arterial stiffness; and (3) to assess the relationship between warfarin use, dp-ucMGP levels, and arterial stiffness in HF. We enrolled 348 subjects with HFpEF (n=96), HFrEF (n=53), or no HF (n=199). Carotid-femoral pulse wave velocity, a measure of large artery stiffness, was measured with arterial tonometry. Dp-ucMGP was measured with ELISA. Dp-ucMGP levels were greater in both HFrEF (582 pmol/L; 95% CI, 444-721 pmol/L) and HFpEF (549 pmol/L; 95% CI, 455-643 pmol/L) compared with controls (426 pmol/L; 95% CI, 377-475 pmol/L; ANCOVA P=0.0067). Levels of dp-ucMGP were positively associated with carotid-femoral pulse wave velocity (standardized ß, 0.31; 95% CI, 0.19-0.42; P<0.0001), which was also true in analyses restricted to patients with HF (standardized ß, 0.34; 95% CI, 0.16-0.52; P=0.0002). Warfarin use was significantly associated with carotid-femoral pulse wave velocity (standardized ß, 0.13; 95% CI, 0.004-0.26; P=0.043), but this relationship was eliminated after adjustment for dp-ucMGP. In conclusion, levels of dp-ucMGP are increased in HFpEF and HFrEF and are independently associated with arterial stiffness. Future studies should investigate whether vitamin K supplementation represents a suitable therapeutic strategy to prevent or reduce arterial stiffness in HFpEF and HFrEF.

Circulating Dephospho-Uncarboxylated Matrix Gla-Protein Is Associated With Kidney Dysfunction and Arterial Stiffness.

BACKGROUND: Large artery stiffening is increased in advanced chronic kidney disease (CKD) but likely develops progressively in earlier stages of CKD. Active matrix Gla-protein (MGP) is a potent vitamin K-dependent inhibitor of vascular calcification. A recent animal model demonstrated intrinsic abnormalities in vitamin K metabolism even in early CKD, but whether early human CKD is associated with vascular vitamin K deficiency is unknown. METHODS: We enrolled 137 adults without HF with varying degrees of renal function: normal estimated glomerular filtration rate (eGFR; >90 ml/min; n = 59), mildly reduced eGFR (stage 2 CKD: eGFR = 60-89 ml/min; n = 53) or at least moderately reduced eGFR (stage 3-5 CKD; eGFR < 60 ml/min; n = 25). Carotid-femoral pulse wave velocity (CF-PWV) was measured with carotid and femoral tonometry. Dephospho-uncarboxylated matrix gla-protein (dp-ucMGP) was measured with enzyme-linked immunosorbent assay (ELISA) (VitaK; Maastricht University; The Netherlands). RESULT: Dp-ucMGP levels were progressively increased with decreasing renal function (eGFR ≥ 90: 247 pmol/l; eGFR 60-89: 488 pmol/l; eGFR < 60: 953 pmol/l; P < 0.0001). These differences persisted after adjustment for multiple potential confounders (eGFR ≥ 90: 314 pmol/l; eGFR 60-89: 414 pmol/l; eGFR < 60: 770 pmol/l; P < 0.0001). In a multivariable model adjusted for various confounders, dp-ucMGP was a significant independent predictor of CF-PWV (ß = 0.21; P = 0.019). In formal mediation analyses, dp-ucMGP mediated a significant relationship between eGFR and higher CF-PWV (ß = -0.16; P = 0.005), whereas no significant dp-ucMGP-independent relationship was present (ß = -0.02; P = 0.80). CONCLUSIONS: CKD is associated with increased (inactive) dp-ucMGP, a vitamin K-dependent inhibitor of vascular calcification, which correlates with large artery stiffness. Further studies are needed to assess whether vitamin K2 supplementation represents a suitable therapeutic strategy to prevent or reduce arterial stiffening in CKD.

Inactive Matrix Gla-Protein and Arterial Stiffness in Type 2 Diabetes Mellitus.

BACKGROUND: Large artery stiffness is increased in diabetes mellitus and causes an excessive pulsatile load to the heart and to the microvasculature. The identification of pathways related to arterial stiffness may provide novel therapeutic targets to ameliorate arterial stiffness in diabetes. Matrix Gla-Protein (MGP) is an inhibitor of vascular calcification. Activation of MGP is vitamin K dependent. We hypothesized that levels of inactive MGP (dephospho-uncarboxylated MGP; dp-ucMGP) are related to arterial stiffness in type 2 diabetes. METHODS: We enrolled a multiethnic cohort of 66 participants with type 2 diabetes. Carotid-femoral pulse wave velocity (CF-PWV) was measured with high-fidelity arterial tonometry (Sphygmocor Device). Dp-ucMGP was measured with ELISA (VitaK; The Netherlands). RESULTS: The majority of the participants were middle-aged (62 ± 12 years), male (91%), and had a history of hypertension (82%). Average hemoglobin A1C was 7.2% (55 mmol/mol). Mean dp-ucMGP was 624 ± 638 pmol/l and mean CF-PWV was 11 ± 4 m/sec. In multivariable analyses, dp-ucMGP was independently related to African American ethnicity (ß = -0.24, P = 0.005), warfarin use (ß = 0.56, P < 0.001), and estimated glomerular filtration rate (eGFR, ß = -0.32, P < 0.001). Dp-ucMGP predicted CF-PWV (ß = 0.40, P = 0.011), even after adjustment for age, gender, ethnicity, mean arterial pressure, eGFR, and warfarin use. CONCLUSIONS: In our cross-sectional analysis, circulating dp-ucMGP was independently associated with CF-PWV in type 2 diabetes. This suggests that deficient vitamin K-dependent activation of MGP may lead to large artery stiffening and could be targeted with vitamin K supplementation in the patients with diabetes.

Dislipidemia aterogénica en latino américa: prevalencia, causas y tratamiento / Atherogenic dyslipidemia in Latin America: prevalence, causes and treatment

En las guías clínicas actuales, la dislipidemia aterogénica (DA) es una entidad no muy atendida. Debido a las frecuentes alteraciones en los lípidos asociados a la DA en Latino América (LA). Métodos: organizamos un grupo de expertos denominado Academia Latino Americana para el estudio de los Lípidos (ALALIP) para así generar un documento con análisis de su prevalencia y recomendaciones terapéuticas prácticas. Se utilizó la metodología Delphi modificada, con una revisión integral de la literatura y énfasis en las publicaciones con implicaciones para LA. Subsecuentemente, desarrollamos preguntas claves para ser discutidas. Resultados: En Latinoamérica (LA) no existe un estudio global sobre los factores de riesgo que representan a la totalidad de la población. El análisis sistemático de las encuestas nacionales de salud y de los estudios sistemáticos de cohorte muestran consistentemente una alta prevalencia de las anormalidades lipídicas que definen la DA. La concentración baja del colesterol unido a las lipoproteínas de alta densidad (C-HDL) varía entre 34,1% a 53,3% y la de triglicéridos (TG) elevados del 25,5% al 31,2%, con mayor prevalencia entre los hombres. La DA bien puede ser tratada con los cambios del estilo de vida (CTEV) como ncremento en laactividad física, dieta baja en carbohidratos y alta en ácidos grasos poliinsaturados, tales como los ácidos grasos omega-3 como intervención primaria. De ser necesario, esta estrategia sera suplementada con terapia farmacológica como la monoterapia con estatinas o la combinación de fibratos/ácidos grasos omega-3. Conclusiones: Las anormalidades lipídicas que definen la DA tienen una elevada prevalencia en LA; su interacción con un estilo de vida no saludable, herencia y cambios epigenéticos están ligados a sus posibles causas. La DA es una causa importante de riesgo cardiovascular residual (RCVR) que debe ser diagnosticada y tratada. Es importante y necesario diseñar un estudio global de factores de riesgo en LA para conocer la real prevalencia de la DA(AU)

In the current clinical guidelines, atherogenic Med Interna (Caracas) 2017; 33 (3): 121 - 139 Dislipidemia Aterogénica en Latino América: Prevalencia, causas y tratamiento Carlos I. Ponte-N, Jesús E. Isea-Pérez, Alberto J. Lorenzatti, Patricio López-Jaramillo, Fernando Stuardo Wyss-Q, Xavier Pintó, Fernando Lanas, Josefina Medina, Livia T. Machado-H, Mónica Acevedo, Paola Varleta Alfonso Bryce, Carlos Carrera, Carlos Ernesto Peñaherrera, José Ramón Gómez-M, Alfredo Lozada, Alonso Merchan-V, Daniel Piskorz, Enrique Morales, María Paniagua, Félix Medina-Palomino, Raúl Alejandro Villar-M, Leonardo Cobos, Enrique Gómez-Álvares, Rodrigo Alonso, Juan Colan, Julio Chirinos, Jofre Lara, Vladimir Ullauri, Ildefonso Arocha Documento de la posición de expertos de la Academia Latino Americana para el estudio de los Lípidos (ALALIP) y avalado por la Sociedad Interamericana de Cardiología (SIAC), Sociedad Sur Americana de Cardiología (SSC), el Colegio Panamericano de Endotelio (CPAE) y la Sociedad Internacional de Aterosclerosis (IAS). Publicado en conjunto con las Revistas de la Sociedad Venezolana de Medicina Interna y de la Sociedad Venezolana de ndocrinología y Metabolismo. dyslipidemia (AD) is a poorly recognized entity. Due to the frequent lipid alterations associated with AD in Latin America (LA), we organized a group of experts named Latin American Academy for the study of Lipids (ALALIP), to generate a document to analize it´s prevalence and to offer practical recommendations. Methodology: Using the Delphi methodology, we conducted a comprehensive literature review, with emphasis on those publications with implications for LA. Subsequently we developed key questions to be discussed. Results: In LA There is no a global study on risk factors that represent the entire population. The systematic analysis of national health surveys and regional cohort studies showed a consistent high prevalence of the lipid abnormalities that define AD. Low high density lipoprotein cholesterol (HDL-C) ranges from 34.1% to 53.3% and elevated triglycerides (TG) from 25.5% to 31.2% more prevalent in men. There are multiple causes: high consumption of foods with a high caloric density, cholesterol and trans fats, sedentary lifestyle and epigenetic changes. AD must be well treated with therapeutic changes in lifestyle with increase in physical activities, regular exercise and a diet with a low proportion of carbohydrates and rich in poliunsatured fatty acid, such as omega-3 fatty acids as primary intervention. If needed, this strategy must be supplemented with pharmacological therapies such as monotherapy with statins or a combination of fibrates plus omega-3. fatty acid. conclusions: Lipid abnormalities that define AD have a high prevalence in LA; the interaction between non-healthy lifestyle, inheritance and epigenetic changes, possibly are the cause. AD is an important cause of cardiovascular residual risk (CVRR), that must be diagnosed and treated It is important and necesary to design a global study of risk factors in LA to know the true prevalence of AD(AU)

Heart Failure, Left Ventricular Remodeling, and Circulating Nitric Oxide Metabolites.

BACKGROUND: Stable plasma nitric oxide (NO) metabolites (NOM), composed predominantly of nitrate and nitrite, are attractive biomarkers of NO bioavailability. NOM levels integrate the influence of NO-synthase-derived NO production/metabolism, dietary intake of inorganic nitrate/nitrite, and clearance of NOM. Furthermore, nitrate and nitrite, the most abundant NOM, can be reduced to NO via the nitrate-nitrite-NO pathway. METHODS AND RESULTS: We compared serum NOM among subjects without heart failure (n=126), subjects with heart failure and preserved ejection fraction (HFpEF; n=43), and subjects with heart failure and reduced ejection fraction (HFrEF; n=32). LV mass and extracellular volume fraction were measured with cardiac MRI. Plasma NOM levels were measured after reduction to NO via reaction with vanadium (III)/hydrochloric acid. Subjects with HFpEF demonstrated significantly lower unadjusted levels of NOM (8.0 µmol/L; 95% CI 6.2-10.4 µmol/L; ANOVA P=0.013) than subjects without HF (12.0 µmol/L; 95% CI 10.4-13.9 µmol/L) or those with HFrEF (13.5 µmol/L; 95% CI 9.7-18.9 µmol/L). There were no significant differences in NOM between subjects with HFrEF and subjects without HF. In a multivariable model that adjusted for age, sex, race, diabetes mellitus, body mass index, current smoking, systolic blood pressure, and glomerular filtration rate, HFpEF remained a predictor of lower NOM (ß=-0.43; P=0.013). NOM did not correlate with LV mass, or LV diffuse fibrosis. CONCLUSIONS: HFpEF, but not HFrEF, is associated with reduced plasma NOM, suggesting greater endothelial dysfunction, enhanced clearance, or deficient dietary ingestion of inorganic nitrate. Our findings may underlie the salutary effects of inorganic nitrate supplementation demonstrated in recent clinical trials in HFpEF.