Cardiovascular calcification is prevalent in the aging population and in patients with chronic kidney disease (CKD) and diabetes mellitus, giving rise to substantial morbidity and mortality. Vitamin K-dependent matrix Gla-protein (MGP) is an important inhibitor of calcification. The aim of this study was to evaluate the impact of high-dose menaquinone-7 (MK-7) supplementation (100 µg/g diet) on the development of extraosseous calcification in a murine model. Calcification was induced by 5/6 nephrectomy combined with high phosphate diet in rats. Sham operated animals served as controls. Animals received high or low MK-7 diets for 12 weeks. We assessed vital parameters, serum chemistry, creatinine clearance, and cardiac function. CKD provoked increased aortic (1.3 fold; p < 0.05) and myocardial (2.4 fold; p < 0.05) calcification in line with increased alkaline phosphatase levels (2.2 fold; p < 0.01). MK-7 supplementation inhibited cardiovascular calcification and decreased aortic alkaline phosphatase tissue concentrations. Furthermore, MK-7 supplementation increased aortic MGP messenger ribonucleic acid (mRNA) expression (10-fold; p < 0.05). CKD-induced arterial hypertension with secondary myocardial hypertrophy and increased elastic fiber breaking points in the arterial tunica media did not change with MK-7 supplementation. Our results show that high-dose MK-7 supplementation inhibits the development of cardiovascular calcification. The protective effect of MK-7 may be related to the inhibition of secondary mineralization of damaged vascular structures.

The lifetime risk of developing heart failure is approximately 20%, and survival rates remain poor. Myocardial mitochondrial function has been suggested to play a pivotal role in heart failure pathophysiology. Human studies on ex vivo mitochondrial function have mostly been limited to atrial tissue obtained during open heart surgery and have provided contradictory results. This study aimed at measuring myocardial mitochondrial function in transcatheter ventricular endomyocardial biopsies and assessing the relationship between oxidative capacity and heart function. We enrolled 40 heart failure patients undergoing ventricular assist device surgery or heart transplantation (34 males, age 57 ± 11 years, body mass index 26.6 ± 4.8 kg/m²) and 29 heart transplant recipients of comparable age and body mass index with normal left ventricular function undergoing surveillance biopsies (23 males, 57 ± 12 years, body mass index 26.2 ± 4.1 kg/m²). High-resolution respirometry was established in the myocardium to measure oxidative capacity ex vivo. The mitochondrial oxidative capacity was 90% higher in ventricular compared to atrial tissues (n = 11, p < 0.01) of explanted hearts. Respiration rates were comparable in ventricular samples of heart failure patients obtained during open heart surgery by standard tissue preparation or ex vivo endomyocardial biopsy (r = 0.9988, p < 0.0001, n = 8), and the mitochondrial oxidative capacity in samples from these patients remained stable for 8 h when stored in either of two common preservation buffers. The oxidative capacity was 44% lower in heart failure than in transplant recipients (67 ± 3 vs. 97 ± 5 pmol/[s mg], p < 0.0001) and correlated positively with heart function (r = 0.49, p < 0.01). High-resolution respirometry of ventricular tissue is feasible in transcatheter biopsies, facilitating clinical studies on myocardial mitochondrial function in patients not undergoing heart surgery.

Aims: Myocardial inflammation and impaired mitochondrial oxidative capacity are hallmarks of heart failure (HF) pathophysiology. The extent of myocardial inflammation in patients suffering from ischaemic cardiomyopathy (ICM) or dilated cardiomyopathy (DCM) and its association with mitochondrial energy metabolism are unknown. We aimed at establishing a relevant role of cardiac inflammation in the impairment of mitochondrial energy production in advanced ischaemic and non-ischaemic HF. Methods: We included 81 patients with stage D HF (ICM, n = 44; DCM, n = 37) undergoing left ventricular assist device implantation (n = 59) or heart transplantation (n = 22) and obtained left ventricular tissue samples during open heart surgery. We quantified mitochondrial oxidative capacity, citrate synthase activity (CSA) and fibrosis and lymphocytic infiltration. We considered infiltration of >14 CD3+ cells/mm2 relevant inflammation. Results: Patients with ICM or DCM did not differ regarding age (61.5 ± 5.7 vs. 56.5 ± 12.7 years, P = 0.164), sex (86% vs. 84% male, P = 0.725), type 2 diabetes mellitus (34% vs. 18%, P = 0.126) or chronic kidney disease (8% vs. 11%, P = 0.994). ICM exhibited oxidative capacity reduced by 23% compared to DCM (108.6 ± 41.4 vs. 141.9 ± 59.9 pmol/(s*mg), P = 0.006). Maximum production of reactive oxygen species was not significantly different between ICM and DCM (0.59 ± 0.28 vs. 0.69 ± 0.36 pmol/(s*ml), P = 0.196). Mitochondrial content, detected by CSA, was lower in ICM (359.6 ± 164.1 vs. 503.0 ± 198.5 nmol/min/mg protein, P = 0.002). Notably, relevant inflammation was more common in ICM (27% vs. 6%, P = 0.024), and the absolute number of infiltrating leucocytes correlated with lower oxidative capacity (r = −0.296, P = 0.019). Fibrosis was more prevalent in ICM (20.9 ± 21.2 vs. 7.2 ± 5.6% of area, P = 0.002), but not associated with oxidative capacity (r = −0.13, P = 0.327). Conclusions: More than every fourth ICM patient with advanced HF displays myocardial inflammation in the range of inflammatory cardiomyopathy associated with reduced mitochondrial oxidative capacity. Future studies may evaluate inflammation in ICM at earlier stages in standardised fashion to explore the therapeutic potential of immunosuppression to influence trajectories of HF in ICM.

Aims To evaluate whether CMR-derived RV assessment can facilitate risk stratification among patients undergoing transcatheter mitral valve repair (TMVR). Background In patients undergoing TMVR, only limited data exist regarding the role of RV function. Previous studies assessed the impact of pre-procedural RV dysfunction stating that RV failure may be associated with increased cardiovascular mortality after the procedure. Methods Sixty-one patients underwent CMR, echocardiography and right heart catheterization prior TMVR. All-cause mortality and heart failure hospitalizations were assessed during 2-year follow-up. Results According to RV ejection fraction (RVEF) Conclusion In patients undergoing TMVR, pre-existing RV dysfunction and RV dilatation are associated with reduced survival, in progressive additive fashion. The assessment of RV volumes and function by CMR may aid in risk stratification prior TMVR in these high-risk patients.