Cocoa flavanol (CF) intake improves endothelial function in patients with cardiovascular risk factors and disease. We investigated the effects of CF on surrogate markers of cardiovascular health in low risk, healthy, middle-aged individuals without history, signs or symptoms of CVD. In a 1-month, open-label, one-armed pilot study, bi-daily ingestion of 450 mg of CF led to a time-dependent increase in endothelial function (measured as flow-mediated vasodilation (FMD)) that plateaued after 2 weeks. Subsequently, in a randomised, controlled, double-masked, parallel-group dietary intervention trial (Clinicaltrials.gov: NCT01799005), 100 healthy, middle-aged (35–60 years) men and women consumed either the CF-containing drink (450 mg) or a nutrient-matched CF-free control bi-daily for 1 month. The primary end point was FMD. Secondary end points included plasma lipids and blood pressure, thus enabling the calculation of Framingham Risk Scores and pulse wave velocity. At 1 month, CF increased FMD over control by 1·2 % (95 % CI 1·0, 1·4 %). CF decreased systolic and diastolic blood pressure by 4·4 mmHg (95 % CI 7·9, 0·9 mmHg) and 3·9 mmHg (95 % CI 6·7, 0·9 mmHg), pulse wave velocity by 0·4 m/s (95 % CI 0·8, 0·04 m/s), total cholesterol by 0·20 mmol/l (95 % CI 0·39, 0·01 mmol/l) and LDL-cholesterol by 0·17 mmol/l (95 % CI 0·32, 0·02 mmol/l), whereas HDL-cholesterol increased by 0·10 mmol/l (95 % CI 0·04, 0·17 mmol/l). By applying the Framingham Risk Score, CF predicted a significant lowering of 10-year risk for CHD, myocardial infarction, CVD, death from CHD and CVD. In healthy individuals, regular CF intake improved accredited cardiovascular surrogates of cardiovascular risk, demonstrating that dietary flavanols have the potential to maintain cardiovascular health even in low-risk subjects.

IntroductionThe key event in the pathogenesis of arteriosclerosis is believed to be a dysfunction of the endothelium with disruption of vascular homeostasis, predisposing blood vessels to vasoconstriction, inflammation, leukocyte adhesion, thrombosis, and proliferation of vascular smooth muscle cells. Red blood cells (RBCs) are typically considered as shuttles of respiratory gases and nutrients for tissues, less so compartments important to vascular integrity. Patients with coronary artery disease (CAD) and concomitant anemia have a poorer prognosis after myocardial infarction, percutaneous coronary intervention, and coronary artery bypass grafting, and are more prone to developing heart failure with fatal outcomes. [1][2][3] Surprisingly, erythropoietin treatment fails to improve diagnosis, indicating that a compromised gas exchange/nutrient transport capacity of blood is insufficient to explain this outcome.Nitric oxide (NO) is an essential short-lived signaling/ regulatory product of a healthy endothelium that is critically important for vascular health. Decreased production and/or bioactivity of NO are a hallmark of endothelial dysfunction and have been shown to contribute to accelerated atherogenesis. In the cardiovascular system, NO is continuously produced in endothelial cells (ECs) by the type III isoform of NO synthase (eNOS, NOS3; EC 1.14.13.39). 4 In addition to endothelial cells, some circulating blood cells also contain eNOS.It is an accepted dogma that RBCs take up and inactivate endothelium-derived NO via rapid reaction with oxyhemoglobin to form methemoglobin and nitrate, thereby limiting NO available for vasodilatation. Yet it has also been shown that RBCs not only act as "NO sinks" but synthesize, store, and transport NO metabolic products. Under hypoxic conditions in particular, it has been demonstrated that RBCs induce NO-dependent vasorelaxation. 5,6 Mechanisms of release and potential sources of NO in RBCs are still a matter of debate, but candidates include iron-nitrosylhemoglobin, 7 S-nitrosohemoglobin, [8][9][10] and nitrite. The latter may form NO either via deoxyhemoglobin 5,11 or xanthine oxidoreductase (XOR)-mediated reduction, 6,12 or via spontaneous 12 and carbonic anhydrase-facilitated disproportionation. 13 Most of these processes show a clear oxygen-dependence, and several are favored by low oxygen tensions. The relative contribution of either mechanism to NO formation varies with oxygen partial pressure along the vascular tree. In addition, RBCs release ATP when subjected to hypoxia, providing an alternative vasodilatory pathway. 14 The publication costs of this article were defrayed in part by page charge payment. Therefore, and solely to indicate this fact, this article is hereby marked ''advertisement'' in accordance with 18 USC section 1734. 16,19 and citrulline 15,18 in the supernatant. However, Kang et al failed to measure citrulline production in RBC lysates, 20 maybe because of loss of cellular structures or cofactors important for activity. 21 Another recent study fai...

Increased vascular stiffness, endothelial dysfunction, and isolated systolic hypertension are hallmarks of vascular aging. Regular cocoa flavanol (CF) intake can improve vascular function in healthy young and elderly at-risk individuals. However, the mechanisms underlying CF bioactivity remain largely unknown. We investigated the effects of CF intake on cardiovascular function in healthy young and elderly individuals without history, signs, or symptoms of cardiovascular disease by applying particular focus on functional endpoints relevant to cardiovascular aging. In a randomized, controlled, double-masked, parallel-group dietary intervention trial, 22 young (<35 years) and 20 elderly (50–80 year) healthy, male non-smokers consumed either a CF-containing drink (450 mg CF) or nutrient-matched, CF-free control drink bi-daily for 14 days. The primary endpoint was endothelial function as measured by flow-mediated vasodilation (FMD). Secondary endpoints included cardiac output, vascular stiffness, conductance of conduit and resistance arteries, and perfusion in the microcirculation. Following 2 weeks of CF intake, FMD improved in young (6.1 ± 0.7 vs. 7.6 ± 0.7 %, p < 0.001) and elderly (4.9 ± 0.6 vs. 6.3 ± 0.9 %, p < 0.001). Secondary outcomes demonstrated in both groups that CF intake decreased pulse wave velocity and lowered total peripheral resistance, and increased arteriolar and microvascular vasodilator capacity, red cell deformability, and diastolic blood pressure, while cardiac output remained affected. In the elderly, baseline systolic blood pressure was elevated, driven by an arterial-stiffness-related augmentation. CF intake decreased aortic augmentation index (−9 %) and thus systolic blood pressure (−7 mmHg; Clinicaltrials.gov: NCT01639781). CF intake reverses age-related burden of cardiovascular risk in healthy elderly, highlighting the potential of dietary flavanols to maintain cardiovascular health.

The ubiquitously expressed aryl hydrocarbon receptor (AhR) induces drug metabolizing enzymes as well as regulators of cell growth, differentiation and apoptosis. Certain AhR ligands promote atherosclerosis, an age-associated vascular disease. Therefore, we investigated the role of AhR in vascular functionality and aging. We report a lower pulse wave velocity in young and old AhR-deficient mice, indicative of enhanced vessel elasticity. Moreover, endothelial nitric oxide synthase (eNOS) showed increased activity in the aortas of these animals, which was reflected in increased NO production. Ex vivo, AhR activation reduced the migratory capacity of primary human endothelial cells. AhR overexpression as well as treatment with a receptor ligand, impaired eNOS activation and reduced S-NO content. All three are signs of endothelial dysfunction. Furthermore, AhR expression in blood cells of healthy human volunteers positively correlated with vessel stiffness. In the aging model Caenorhabditis elegans, AhR-deficiency resulted in increased mean life span, motility, pharynx pumping and heat shock resistance, suggesting healthier aging. Thus, AhR seems to have a negative impact on vascular and organismal aging. Finally, our data from human subjects suggest that AhR expression levels could serve as an additional, new predictor of vessel aging.

A substantial interaction between cocoa flavanols and methylxanthines exists at the level of absorption, in which the methylxanthines mediate an increased plasma concentration of (-)-epicatechin metabolites that coincides with enhanced vascular effects commonly ascribed to cocoa flavanol intake. This trial was registered at clinicaltrials.gov as NCT02149238.