The actions of methotrexate on endothelial cells are dependent on the shear stress-induced regulation of one carbon metabolism.

Objectives: The disease-modifying anti-rheumatic drug methotrexate (MTX) is recognized to reduce cardiovascular risk in patients with systemic inflammatory diseases. However, the molecular basis for these cardioprotective effects remains incompletely understood. This study evaluated the actions of low-dose MTX on the vascular endothelium. Methods: Human endothelial cells (EC) were studied under in vitro conditions relevant to inflammatory arthritis. These included culture in a pro-inflammatory microenvironment and exposure to fluid shear stress (FSS) using a parallel plate model. Respectively treated cells were analyzed by RNA sequencing and quantitative real-time PCR for gene expression, by immunoblotting for protein expression, by phosphokinase activity arrays, by flow cytometry for cell cycle analyses and by mass spectrometry to assess folate metabolite levels. Results: In static conditions, MTX was efficiently taken up by EC and caused cell cycle arrest concurrent with modulation of cell signaling pathways. These responses were reversed by folinic acid (FA), suggesting that OCM is a predominant target of MTX. Under FSS, MTX did not affect cell proliferation or pro-inflammatory gene expression. Exposure to FSS downregulated endothelial one carbon metabolism (OCM) as evidenced by decreased expression of key OCM genes and metabolites. Conclusion: We found that FSS significantly downregulated OCM and thereby rendered EC less susceptible to the effects of MTX treatment. The impact of shear stress on OCM suggested that MTX does not directly modulate endothelial function. The cardioprotective actions of MTX likely reflect direct actions on inflammatory cells and indirect benefit on the vascular endothelium.

Hemodynamic Thresholds for Precapillary Pulmonary Hypertension.

BACKGROUND: Hemodynamic differentiation between pulmonary arterial hypertension (PAH) and postcapillary pulmonary hypertension (PH) is important because treatment options are strikingly different for the two disease subsets. Whereas patients with PAH can be treated effectively with targeted therapies, their use in postcapillary PH is currently not recommended. Our aim was to establish an algorithm to identify patients who are likely to experience a significant hemodynamic treatment response. METHODS: We determined hemodynamic cutoffs to discriminate between idiopathic PAH and postcapillary PH in a large database of 4,363 stable patients undergoing first diagnostic right and left heart catheterizations. In a second step, we performed a patient-level pooled analysis of four randomized, placebo-controlled trials including 541 patients with PAH who received treprostinil or placebo, to validate hemodynamic cutoffs with regard to treatment response. RESULTS: Receiver operating characteristic analysis identified mean pulmonary arterial wedge pressure (mPAWP) < 12 mm Hg and diastolic pulmonary vascular pressure gradient (DPG) ≥ 7 mm Hg as the best hemodynamic discriminators between idiopathic PAH and postcapillary PH. In our treatment study, only patients with mPAWP < 12 mm Hg, DPG > 20 mm Hg or a combination of both had a significant placebo-corrected improvement in hemodynamics. CONCLUSIONS: mPAWP < 12 mm Hg and DPG > 20 mm Hg identify patients with PAH who are likely to have significant hemodynamic improvement with prostacyclin treatment.

Pulmonary Hypertension in Heart Failure. Epidemiology, Right Ventricular Function, and Survival.

RATIONALE: Patients with pulmonary hypertension due to left heart disease (PH-LHD) and a diastolic pulmonary vascular pressure gradient ≥ 7 mm Hg, representing PH out of proportion to pulmonary arterial wedge pressure, have pulmonary vascular disease and increased mortality. Little information exists on this condition, recently labeled as "combined pre- and post-capillary PH" (Cpc-PH). OBJECTIVES: To investigate epidemiology, risk factors, right ventricular function, and outcomes in patients with chronic heart failure and Cpc-PH. METHODS: The study population was identified from a retrospective chart review of a clinical database of 3,107 stable patients who underwent first diagnostic right heart catheterization and from a prospective cohort of 800 consecutive patients at a national university-affiliated tertiary center. MEASUREMENTS AND MAIN RESULTS: The retrospective cohort had 664 patients with systolic heart failure (SHF) and 399 patients with diastolic heart failure (DHF), 12% of whom were classified as Cpc-PH. The prospective cohort had 172 patients with SHF (14% Cpc-PH) and 219 patients with DHF (12% Cpc-PH). Chronic obstructive pulmonary disease (P = 0.034) and the tricuspid annular plane systolic excursion to systolic pulmonary artery pressure ratio (P = 0.015) predicted Cpc-PH in SHF. Younger age (P = 0.004), valvular heart disease (P = 0.046), and the tricuspid annular plane systolic excursion to systolic pulmonary artery pressure ratio predicted Cpc-PH in DHF (P = 0.016). Right ventricular-pulmonary vascular coupling was worse in Cpc-PH patients (end-systolic elastance to effective arterial elastance [Ees/Ea]: SHF: 1.05 ± 0.25; P = 0.002; DHF: 1.17 ± 0.27; P = 0.027) than in those with isolated post-capillary PH (Ees/Ea: SHF: 1.52 ± 0.51; DHF: 1.45 ± 0.29). CONCLUSIONS: Cpc-PH is rare in chronic heart failure. Right ventricular-pulmonary vascular coupling is poor in Cpc-PH and could be one explanation for dismal outcomes.

Diastolic pulmonary vascular pressure gradient: a predictor of prognosis in "out-of-proportion" pulmonary hypertension.

BACKGROUND: Left-sided heart disease (LHD) is the most common cause of pulmonary hypertension (PH). In patients with LHD, elevated left atrial pressure causes a passive increase in pulmonary vascular pressure by hydrostatic transmission. In some patients, an active component caused by pulmonary arterial vasoconstriction and/or vascular remodeling superimposed on left-sided pressure elevation is observed. This "reactive" or "out-of-proportion" PH, defined as PH due to LHD with a transpulmonary gradient (TPG) > 12 mm Hg, confers a worse prognosis. However, TPG is sensitive to changes in cardiac output and left atrial pressure. Therefore, we tested the prognostic value of diastolic pulmonary vascular pressure gradient (DPG) (ie, the difference between invasive diastolic pulmonary artery pressure and mean pulmonary capillary wedge pressure) to better prognosticate death in "out-of-proportion" PH. METHODS: A large database of consecutive cases was analyzed. One thousand ninety-four of 2,351 complete data sets were from patients with PH due to LHD. For proof of concept, available lung histologies were reviewed. RESULTS: In patients with postcapillary PH and a TPG > 12 mm Hg, a worse median survival (78 months) was associated with a DPG ≥ 7 mm Hg compared with a DPG < 7 mm Hg (101 months, P = .010). Elevated DPG was associated with more advanced pulmonary vascular remodeling. CONCLUSIONS: DPG identifies patients with "out-of-proportion" PH who have significant pulmonary vascular disease and increased mortality. We propose a diagnostic algorithm, using pulmonary capillary wedge pressure, TPG, and DPG in sequence to diagnose pulmonary vascular disease superimposed on left-sided pressure elevation.