Cardiovascular disease is the major cause of morbidity and mortality in breast cancer survivors. Chemotherapy contributes to this risk. We aimed to define the mechanisms of long-term vascular dysfunction caused by neoadjuvant chemotherapy (NACT) and identify novel therapeutic targets. We studied arteries from postmenopausal women who had undergone breast cancer treatment using docetaxel, doxorubicin, and cyclophosphamide (NACT) and from women with no history of such treatment matched for key clinical parameters. We explored mechanisms in WT and Nox4^–/– mice and in human microvascular endothelial cells. Endothelium-dependent, NO-mediated vasodilatation was severely impaired in patients after NACT, while endothelium-independent responses remained normal. This was mimicked by a 24-hour exposure of arteries to NACT agents ex vivo. When applied individually, only docetaxel impaired endothelial function in human vessels. Mechanistic studies showed that NACT increased inhibitory eNOS phosphorylation of threonine 495 in a Rho-associated protein kinase–dependent (ROCK-dependent) manner and augmented vascular superoxide and hydrogen peroxide production and NADPH oxidase activity. Docetaxel increased expression of the NADPH oxidase NOX4 in endothelial and smooth muscle cells and NOX2 in the endothelium. A NOX4 increase in human arteries may be mediated epigenetically by diminished DNA methylation of the NOX4 promoter. Docetaxel induced endothelial dysfunction and hypertension in mice, and these were prevented in Nox4^–/– mice and by pharmacological inhibition of Nox4 or Rock. Commonly used chemotherapeutic agents and, in particular, docetaxel alter vascular function by promoting the inhibitory phosphorylation of eNOS and enhancing ROS production by NADPH oxidases.

BACKGROUND: Higher levels of plasma glycine are linked to a reduced risk, while increased levels of total branched-chain amino acids (tBCAAs) are associated with a higher risk of essential hypertension and coronary heart disease (CHD). As these metabolic components are interconnected, analyzing the tBCAAs/glycine ratio may help to understand their interplay in the pathogenesis of cardiovascular disease. METHODS: The Cox regression approach was combined with the development of novel genetic tools for assessments of associations between plasma metabolomic data (glycine, tBCAAs, and tBCAAs/glycine ratio) from the UK Biobank and the development of hypertension and CHD. Genome-wide association study was performed on 186 523 White UK Biobank participants to identify new independent genetic instruments for the 2-sample Mendelian randomization analyses. P -gain statistic >10 identified instruments associated with tBCAAs/glycine ratio significantly stronger compared with individual amino acids. Outcomes of genome-wide association study on hypertension and CHD were derived from the UK Biobank (nonoverlapping sample), FinnGen, and CARDIoGRAMplusC4D. RESULTS: The tBCAAs/glycine ratio was prospectively associated with a higher risk of developing hypertension and CHD (hazard ratio quintile Q5 versus Q1, 1.196 [95% CI, 1.109–1.289] and 1.226 [95% CI, 1.160–1.296], respectively). Mendelian randomization analysis demonstrated that tBCAAs/glycine ratio ( P -gain >10) was a risk factor for hypertension (meta-analyzed inverse-variance weighted causal estimate 0.45 log odds ratio/SD (95% CI, 0.26–0.64) and CHD (0.48 [95% CI, 0.29–0.67]) with an absolute effect significantly larger compared with the effect of glycine (−0.06 [95% CI, −0.1 to −0.03] and −0.08 [95% CI, −0.11 to −0.05], respectively) or tBCAAs (0.22 [95% CI, 0.09–0.34] and 0.12 [95% CI, 0.01–0.24], respectively). CONCLUSIONS: The total BCAAs/glycine ratio is a key element of the metabolic signature contributing to hypertension and CHD, which may reflect biological pathways shared by glycine and tBCAAs.

Background: Although degenerative aortic valve stenosis (DAS) is the most prevalent growth-up congestive heart valve disease, still little known about relationships between DAS severity, vascular stiffness (VS), echocardiographic parameters, and serum biomarkers in patients undergoing transcatheter (TAVR) or surgical aortic valve replacement (SAVR). The objective of this study was to identify biomarkers associated with DAS severity, and those that are associated with cardiovascular death (CVD) and episodes of chronic heart failure (CHF) exacerbation. Methods: A total of 137 patients with initially moderate-to-severe DAS were prospectively evaluated for the relationship between DAS severity, baseline VS, and serum biomarkers (uPAR, GDF-15, Gal-3, IL-6Rα, ET-1, PCSK9, RANTES/CCL5, NT-proBNP, and hs-TnT), and were followed-up for 48 months. The prognostic significance of each variable for CVD and CHF risk was measured by hazard ratio of risk (HR), which was calculated by Cox’s proportional hazard model. Results: DAS severity showed correlations with IL-6Rα (r = 0.306, p < 0.001), uPAR (r = 0.184, p = 0.032), and NT-proBNP (r = −0.389, p < 0.001). Levels of ET-1 and Gal-3 were strongly correlated with VS parameters (r = 0.674, p < 0.001; r = 0.724, p < 0.001). Out of 137 patients, 20 were referred to TAVR, 88 to SAVR, and 29 to OMT. In TAVR patients, the highest levels of ET-1, Gal-3, and VS were found as compared to other patients. The highest incidence of CVD was observed in patients who underwent TAVR (35%), compared to SAVR (8%) and OMT (10.3%) (p = 0.004). In a multivariate analysis, ET-1 occurred predictive of CVD risk (HR 25.1, p = 0.047), while Gal-3 > 11.5 ng/mL increased the risk of CHF exacerbation episodes requiring hospital admission by 12%. Conclusions: Our study indicated that ET-1 and Gal-3 levels may be associated with the outcomes in patients with DAS.

Sphingosine kinase-1 (Sphk1) and its product, sphingosine-1-phosphate (S1P) are important regulators of cardiac growth and function. Numerous studies have reported that Sphk1/S1P signaling is essential for embryonic cardiac development and promotes pathological cardiac hypertrophy in adulthood. However, no studies have addressed the role of Sphk1 in postnatal cardiomyocyte (CM) development so far. The present study aimed to assess the molecular mechanism(s) by which Sphk1 silencing might influence CMs development and hypertrophy in vitro. Neonatal mouse CMs were transfected with siRNA against Sphk1 or negative control, and subsequently treated with 1 µM angiotensin II (AngII) or a control buffer for 24 h. The results of RNASeq analysis revealed that diminished expression of Sphk1 significantly accelerated neonatal CM maturation by inhibiting cell proliferation and inducing developmental pathways in the stress (AngII-induced) conditions. Importantly, similar effects were observed in the control conditions. Enhanced maturation of Sphk1-lacking CMs was further confirmed by the upregulation of the physiological hypertrophy-related signaling pathway involving Akt and downstream glycogen synthase kinase 3 beta (Gsk3β) downregulation. In summary, we demonstrated that the Sphk1 silencing in neonatal mouse CMs facilitated their postnatal maturation in both physiological and stress conditions.

BACKGROUND: S1P (sphingosine-1-phosphate) signaling plays a key role in regulating the cardiovascular system. In experimental essential hypertension (HTN), expression of Sphk1 (sphingosine kinase 1), a key S1P-producing enzyme, is upregulated in the vasculature. Mice with global Sphk1 deletion exhibit alleviated AngII (angiotensin II)-induced HTN. However, cellular mechanisms underlying this protective effect remain unclear due to pleiotropic S1P actions. METHODS: Mice with targeted deletion of Sphk1 in smooth muscle cells (SMCs) or endothelial cells were generated using the Cre-loxP system. To induce HTN, mice were infused with AngII (490 ng/min per kilogram for 14 days), using osmotic minipumps. Blood pressure was monitored, and vascular structure and function were assessed ex vivo using wire/pressure myography and histological analysis. To identify mechanistic pathways, RNA sequencing was performed on mouse aortas and mesenteric arteries, followed by Gene Set Enrichment Analysis and validation by RT-qPCR/Western blotting. RESULTS: SMC-specific deletion of Sphk1 conferred significant protection against HTN (mean systolic blood pressure±SD, 131.5±14.6 versus 168.3±14.3 mm Hg in WT ^f/f control, P <0.05). Endothelial cell–specific Sphk1 knockout developed HTN comparable to WT ^f/f . Reduced systolic blood pressure in AngII-infused SMC knockout- Sphk1 was linked to reduced myogenic tone and decreased expression of Rock1/2 (Rho-associated protein kinase 1 and 2) in mesenteric arteries. Despite protection from HTN, mesenteric arteries of AngII-infused SMC knockout- Sphk1 mice were stiffer and exhibited impaired vasorelaxation, associated with excessive Fn1 (fibronectin 1) deposition. An inverse correlation between FN1 and SPHK1 protein expression was also observed in human arteries. Notably, these arterial alterations were absent in normotensive SMC knockout- Sphk1 mice. CONCLUSIONS: SMC-derived Sphk1 plays a predominant role in AngII-induced HTN by modulating myogenic tone.

Ewelina Józefczuk, PhD, Mateusz Siedlinski, PhD; Uncovering vascular signature of sphingosine-1-phosphate receptor 1 activation, Cardiovascular Research, ,