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Background: The mevalonate pathway generates endogenous cholesterol and intermediates including geranylgeranyl pyrophosphate (GGPP). By reducing GGPP production, statins exert pleiotropic or cholesterol-independent effects. The potential regulation of GGPP homeostasis through dietary intake and the interaction with concomitant statin therapy is unknown., Methods: We developed a sensitive high-pressure liquid chromatography technique to quantify dietary GGPP and conducted proteomics, qualitative real-time polymerase chain reaction screening, and Western blot to determine signaling cascades, gene expression, protein-protein interaction, and protein membrane trafficking in wild-type and transgenic rats., Results: GGPP contents were highly variable depending on food source that differentially regulated blood GGPP levels in rats. Diets containing intermediate and high GGPP reduced or abolished the effects of statins in rats with hypoxia- and monocrotaline-induced pulmonary hypertension: this was rescuable by methyl-allylthiosulfinate and methyl-allylthiosulfinate-rich garlic extracts. In human pulmonary artery smooth muscle cells treated with statins, hypoxia activated RhoA in an extracellular GGPP-dependent manner. Hypoxia-induced ROCK2 (Rho associated coiled-coil containing protein kinase 2)/Rab10 (Ras-related protein rab-10) signaling was prevented by statin and recovered by exogenous GGPP. The hypoxia-activated RhoA/ROCK2 pathway in rat and human pulmonary artery smooth muscle cells upregulated the expression of Ca 2+ -sensing receptor (CaSR) and HIMF (hypoxia-induced mitogenic factor), a mechanism attenuated by statin treatment and regained with exogenous GGPP. Rab10 knockdown almost abrogated hypoxia-promoted CaSR membrane trafficking, a process diminished by statin and resumed by exogenous GGPP. Hypoxia-induced pulmonary hypertension was reduced in rats with CaSR mutated at the binding motif of HIMF and the interaction between dietary GGPP and statin efficiency was abolished. In humans fed a high GGPP diet, blood GGPP levels were increased. This abolished statin-lowering effects on plasma GGPP, and also on hypoxia-enhanced RhoA activity of blood monocytes that was rescued by garlic extracts., Conclusions: There is important dietary regulation of GGPP levels that interferes with the effects of statin therapy in experimental pulmonary hypertension. These observations rely on a key and central role of RhoA-ROCK2 cascade activation and Rab10-faciliated CaSR membrane trafficking with subsequent overexpression and binding of HIMF to CaSR. These findings warrant clinical investigation for the treatment of pulmonary hypertension and perhaps other diseases by combining statin with garlic-derived methyl-allylthiosulfinate or garlic extracts and thus circumventing dietary GGPP variations.

Background: C-reactive protein (CRP) is a heritable marker of chronic inflammation that is strongly associated with cardiovascular disease. We sought to identify genetic variants that are associated with CRP levels., Methods and Results: We performed a genome-wide association analysis of CRP in 66 185 participants from 15 population-based studies. We sought replication for the genome-wide significant and suggestive loci in a replication panel comprising 16 540 individuals from 10 independent studies. We found 18 genome-wide significant loci, and we provided evidence of replication for 8 of them. Our results confirm 7 previously known loci and introduce 11 novel loci that are implicated in pathways related to the metabolic syndrome (APOC1, HNF1A, LEPR, GCKR, HNF4A, and PTPN2) or the immune system (CRP, IL6R, NLRP3, IL1F10, and IRF1) or that reside in regions previously not known to play a role in chronic inflammation (PPP1R3B, SALL1, PABPC4, ASCL1, RORA, and BCL7B). We found a significant interaction of body mass index with LEPR (P<2.9×10(-6)). A weighted genetic risk score that was developed to summarize the effect of risk alleles was strongly associated with CRP levels and explained ≈5% of the trait variance; however, there was no evidence for these genetic variants explaining the association of CRP with coronary heart disease., Conclusions: We identified 18 loci that were associated with CRP levels. Our study highlights immune response and metabolic regulatory pathways involved in the regulation of chronic inflammation.

Background: Cholesterol lowering reduces coronary events. One mechanism could be improvement of endothelial function. In line with this hypothesis, this study investigates whether cholesterol reduction can result in rapid improvement of endothelial function after acute coronary syndromes., Methods and Results: Patients with acute myocardial infarction or unstable angina and total cholesterol levels at admission >/=5.2 mmol/L or LDL >/=3.4 mmol/L were randomized to placebo (n=30) or pravastatin 40 mg daily (n=30) for 6 weeks. Brachial ultrasound was used to measure endothelium-dependent flow-mediated dilatation (FMD) and response to endothelium-independent nitroglycerin. Changes in the levels of markers of platelet activation, coagulation factors, and plasma endothelin levels were also assessed. Total and LDL cholesterol levels were similar at admission and before randomization in both groups. With pravastatin, but not with placebo, they decreased by 23% (P<0.05) and 33% (P<0.01), respectively. FMD was unchanged with placebo, 5.43+/-0.74% (mean+/-SEM) to 5.84+/-0.81%, but increased with pravastatin, 4.93+/-0.81% to 7.0+/-0.79% (P=0.02), representing a 42% relative increase. Responses to nitroglycerin were similar during the time course of the study in the 2 groups. Markers of platelet activity, coagulation factors, and endothelin levels were not affected by pravastatin., Conclusions: Cholesterol reduction with pravastatin initiated early after acute coronary syndromes rapidly improves endothelial function after 6 weeks of therapy.

Background: The pulmonary vascular bed is a major site for endothelin-1 (ET-1) clearance. A reduced clearance could contribute to the increase in circulating ET-1 levels found in heart failure (HF). We therefore evaluated the effect of HF on pulmonary ET-1 clearance and on plasma ET-1 concentrations., Methods and Results: Rats with myocardial infarction (n=24) were compared with sham-operated rats (n=22). The lungs were isolated and perfused at a constant flow rate of 10 mL/min. Pulmonary ET-1 clearance was measured by the single-bolus indicator-dilution technique with 125I-labeled ET-1. Infarct rats developed HF with mild pulmonary hypertension. ET-1 extraction was reduced by HF from 63+/-1.5% to 41+/-4.5% (mean+/-SEM, P<0.001). Mixed venous (MV) and aortic ET-1 levels doubled with HF. There was a plasma ET-1 gradient across the lungs of sham rats (MV-aortic levels, 0.21+/-0.12 pg/mL) but not in lungs of HF rats (0.01+/-0.17 pg/mL). Plasma ET-1 levels correlated closely and inversely with ET-1 extraction (P<0.001)., Conclusions: HF is associated with reduced pulmonary ET-1 clearance that contributes to the increase in circulating levels.

Background: Nitric oxide (NO) and endothelin (ET) have been implicated in the pathogenesis of pulmonary hypertension (PH). Chronic ETA antagonist therapy reduces PH in monocrotaline (MCT)-treated rats. Interactions between the L-arginine-NO pathway and the ET system have been described. We therefore studied the effect of long-term treatment with an oral ETA antagonist (LU 135252) on NO-related vasodilation in isolated lungs from control rats and rats with MCT-induced PH., Methods and Results: Three weeks after MCT injection, PH was associated with an increase in right ventricular pressure (from 27.4 +/- 0.9 to 66.6 +/- 4.1 mm Hg) and a decrease in endothelium-independent vasodilation in response to sodium nitroprusside (10(-10) to 10(-5) mol/L; delta Emax, from 11.1 +/- 0.9 to 2.7 +/- 0.3 mm Hg). Endothelium-dependent vasodilation in response to acetylcholine (10(-9) to 10(-4) mol/L) and the calcium ionophore A23187 (10(-9) to 10(-7) mol/L) remained unaffected. Treatment with LU 135252 did not significantly affect the endothelium-dependent and -independent vasodilations in control rats. However, in MCT-treated rats, LU 135252 therapy significantly reduced right ventricular pressure (39.7 +/- 2.1 mm Hg), potentiated acetylcholine-induced vasodilatation (delta Emax, from 1.6 +/- 0.2 to 3.7 +/- 0.4 mm Hg), and improved the responses to sodium nitroprusside (delta Emax, from 2.7 +/- 0.3 to 5.6 +/- 0.6 mm Hg). LU 135252 did not significantly alter the non-receptor-mediated endothelium-dependent vasodilation to A23187 or pulmonary constitutive NO synthase activity., Conclusions: MCT PH is associated with a reduced smooth muscle responsiveness to NO but a maintained endothelium-dependent vasodilatory potency. Long-term ETA antagonist therapy not only restores smooth muscle responsiveness to NO but also increases endothelium-dependent dilation in response to acetylcholine. This mechanism may contribute to the therapeutic benefit of ETA antagonists in PH.

Background: Animal studies suggest a major role of the pulmonary circulation in the clearance of circulating endothelin-1 (ET-1). The contribution of the human pulmonary circulation to plasma ET-1 clearance, however, has never been quantified. The absence of an AV gradient in plasma ET-1 has previously been interpreted as evidence that the lungs do not have a role in modulating circulating ET-1 levels. This study was designed to quantify and discern between pulmonary ET-1 clearance and production in humans., Methods and Results: We studied 13 subjects by combining the multiple indicator-dilution technique with the measurement of immunoreactive ET-1 (irET-1). All patients had normal left ventricular ejection fractions (61 +/- 7%, mean +/- SD) and baseline hemodynamics. Mean pulmonary ET-1 extraction was 47 +/- 7%. The ET-1 extracted does not return to circulation and can be characterized by a sequestration rate constant: Kseq = 0.048 +/- 0.019 s-1. There was no significant difference between irET-1 levels from the pulmonary artery and aorta (0.61 +/- 0.29 and 0.68 +/- 0.33 pg/mL, respectively; P = .22); the normal lung consequently produces an amount of ET-1 that is quantitatively similar to the amount that has been extracted., Conclusions: The human lung is an important site for both clearance and production of ET-1. There is a normal physiological balance of ET-1 across the pulmonary circulation, which explains the absence of difference in AV ET-1 levels despite a 47 +/- 7% clearance. Reduced pulmonary clearance or increased production of this peptide may contribute to the increase in circulating levels found in various cardiovascular conditions.