Publications by authors named "Todd Kolb"

Introduction: Pulmonary arterial hypertension (PAH) involves progressive cellular and molecular change within the pulmonary vasculature, leading to increased vascular resistance. Current therapies targeting nitric oxide (NO), endothelin, and prostacyclin pathways yield variable treatment responses. Patients with systemic sclerosis-associated PAH (SSc-PAH) often experience worse outcomes than those with idiopathic PAH (IPAH).

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Background: Ineffective right ventricular (RV) adaptation to increasing pulmonary arterial (PA) afterload in pulmonary vascular disease (PVD) significantly contributes to morbidity and mortality. Pulmonary vascular disease in systemic sclerosis (SSc) arises through various mechanisms, yet detecting abnormal contractile response remains challenging. Here we examine whether echocardiographic RV-PA coupling metrics correlate with invasive pressure-volume (PV) loops, enhancing the prediction of adverse clinical outcomes in SSc-PVD patients.

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Lung endothelium resides at the interface between the circulation and the underlying tissue, where it senses biochemical and mechanical properties of both the blood as it flows through the vascular circuit and the vessel wall. The endothelium performs the bidirectional signaling between the blood and tissue compartments that is necessary to maintain homeostasis while physically separating both, facilitating a tightly regulated exchange of water, solutes, cells, and signals. Disruption in endothelial function contributes to vascular disease, which can manifest in discrete vascular locations along the artery-to-capillary-to-vein axis.

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Pulmonary hypertension (PH) arises from increased pulmonary vascular resistance due to contraction and remodeling of the pulmonary arteries. The structural changes include thickening of the smooth muscle layer from increased proliferation and resistance to apoptosis. The mechanisms underlying apoptosis resistance in PH are not fully understood.

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Background: Pulmonary arterial hypertension (PAH) is characterised by poor exercise tolerance. The contribution of right ventricular (RV) diastolic function to the augmentation of cardiac output during exercise is not known. This study leverages pressure-volume (-) loop analysis to characterise the impact of RV diastology on poor flow augmentation during exercise in PAH.

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Pulmonary hypertension (PH) is a condition in which remodeling of the pulmonary vasculature leads to hypertrophy of the muscular vascular wall and extension of muscle into nonmuscular arteries. These pathological changes are predominantly due to the abnormal proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs), enhanced cellular functions that have been linked to increases in the cell membrane protein aquaporin 1 (AQP1). However, the mechanisms underlying the increased AQP1 abundance have not been fully elucidated.

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In this 4D flow cardiovascular magnetic resonance (CMR) study, vortical blood flow in the main pulmonary artery (MPA) is quantified using circulation (ᴦ), a metric used in fluid dynamics to quantify the rotational components of flow. Circulation (ᴦ) is a 4D flow CMR metric that quantifies the vortical blood flow pattern in the MPA of patients with pulmonary hypertension (PH), distinguishes them from healthy controls, and shows high correlation with invasive markers of PH severity.

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Although PAH is partially attributed to disordered metabolism, previous human studies have mostly examined circulating metabolites at a single time point, potentially overlooking crucial disease biology. Current knowledge gaps include an understanding of temporal changes that occur within and across relevant tissues, and whether observed metabolic changes might contribute to disease pathobiology. We utilized targeted tissue metabolomics in the Sugen hypoxia (SuHx) rodent model to investigate tissue-specific metabolic relationships with pulmonary hypertensive features over time using regression modeling and time-series analysis.

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Right ventricular (RV) adaptation is the principal determinant of outcomes in pulmonary arterial hypertension (PAH), however, RV function is challenging to assess. RV responses to hemodynamic stressors are particularly difficult to interrogate without invasive testing. This study sought to identify metabolomic markers of in vivo right ventricular function and exercise performance in PAH.

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We have previously identified mitogen-activated protein kinase-activated protein kinase 2 (MK2) is required for caspase-3 nuclear translocation in the execution of apoptosis; however, little is known of the underlying mechanisms. Therefore, we sought to determine the role of kinase and nonkinase functions of MK2 in promoting nuclear translocation of caspase-3. We identified two non-small cell lung cancer cell lines for use in these experiments based on low MK2 expression.

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Non-small cell lung cancers (NSCLCs) demonstrate intrinsic resistance to cell death, even after chemotherapy. Previous work suggested defective nuclear translocation of active caspase-3 in observed resistance to cell death. We have identified mitogen-activated protein kinase-activated protein kinase 2 (MK2; encoded by the gene ) is required for caspase-3 nuclear translocation in the execution of apoptosis in endothelial cells.

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To date, it remains unclear whether recent changes in the management of patients with systemic sclerosis-associated pulmonary hypertension (SSc-PH) have improved survival. To describe a cohort of patients with SSc-PH and compare their characteristics and survival between the last two decades. Patients with SSc-PH prospectively enrolled in the Johns Hopkins Pulmonary Hypertension Center Registry were grouped into two cohorts based on the date of diagnostic right heart catheterization: cohort A included patients whose disease was diagnosed between 1999 and 2010, and cohort B included those whose disease was diagnosed between 2010 and 2021.

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Background: Given the morbidity and mortality associated with pulmonary arterial hypertension (PAH), risk stratification approaches that guide therapeutic management have been previously employed. However, most patients remain in the intermediate-risk category despite initial therapy. Herein, we sought to determine whether echocardiographic parameters could improve the risk stratification of intermediate-risk patients.

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Background: Echocardiography (2DE) is integral for screening and longitudinal evaluation of pulmonary arterial hypertension (PAH) in systemic sclerosis (SSc). In the present study, we sought to establish the reliability, repeatability, and reproducibility of 2DE parameters in SSc patients with and without PAH and to define the minimal detectable difference (MDD), the smallest change detected beyond measurement error.

Methods: SSc patients without known PAH and with invasively confirmed PAH on stable therapies underwent 2DE with strain at two time points.

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Rationale: Pulmonary arterial hypertension (PAH) is a rare disease characterised by limited survival despite remarkable improvements in therapy. The causes, clinical burden and outcomes of patients admitted to the intensive care unit (ICU) remain poorly characterised. The aim of this study was to describe patient characteristics, causes of ICU hospitalisation, and risk factors for ICU and 1-year mortality.

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Cardiac magnetic resonance (CMR) measures of right ventricular (RV) mass, volumes, and function have diagnostic and prognostic value in pulmonary arterial hypertension (PAH). We hypothesized that RV mass-based metrics would discriminate incident PAH as redefined by the lower mean pulmonary arterial pressure (mPAP) threshold of >20 mmHg at the Sixth World Symposium on Pulmonary Hypertension (6th WSPH). Eighty-nine subjects with suspected PAH underwent CMR imaging, including 64 subjects with systemic sclerosis (SSc).

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Background: Soluble Fms-like tyrosine kinase 1 (sFlt-1) may inhibit angiogenesis. Higher levels of sFlt-1 are associated with worse prognosis in prevalent heart failure patients. The aim of this study was to better understand the role of sFlt-1 in heart failure pathogenesis by characterizing relationships between sFlt-1, cardiac morphology, and the composite outcome of incident heart failure or cardiovascular (CV) death in in a multiethnic cohort free of CV disease at baseline.

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Pulmonary hypertension (PH) is a disease that has many etiologies and is particularly prevalent in patients presenting for cardiac surgery, with which it is linked to poor outcomes. This manuscript is intended to provide a comprehensive review of the impact of PH on the perioperative management of patients who are undergoing cardiac surgery. The diagnosis of PH often involves a combination of noninvasive and invasive testing, whereas preoperative optimization frequently necessitates the use of specific medications that affect anesthetic management of these patients.

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Right ventricular function has prognostic significance in patients with pulmonary hypertension. We evaluated whether cardiac magnetic resonance-derived strain and strain rate parameters could reliably reflect right ventricular systolic and diastolic function in precapillary pulmonary hypertension. End-systolic elastance and the time constant of right ventricular relaxation tau, both derived from invasive high-fidelity micromanometer catheter measurements, were used as gold standards for assessing systolic and diastolic right ventricular function, respectively.

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Inhibition of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterases (PDEs) is a cornerstone of pulmonary arterial hypertension (PAH)-specific therapy. PDE9A, expressed in the heart and lung tissue, has the highest affinity for cGMP of all known PDEs. PDE9A deficiency protects mice against chronic left ventricular (LV) pressure overload via increased natriuretic peptide (NP)-dependent cGMP signaling.

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Rationale: Pulmonary hypertension (PH) is associated with significant perioperative morbidity and mortality. We hypothesised that pulmonary arterial hypertension (PAH) composite risk assessment scores could estimate perioperative risk for PH patients when adjusted for inherent procedural risk.

Methods: We identified patients in the Johns Hopkins PH Center Registry that had noncardiac surgery (including endoscopies) between September 2015 and January 2020.

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Background: Angiopoietin-1 and 2 (Ang1, Ang2) are important mediators of angiogenesis. Angiopoietin levels are perturbed in cardiovascular disease, but it is unclear whether angiopoietin signaling is causative, an adaptive response, or merely epiphenomenon of disease activity.

Methods And Results: In a cohort free of cardiovascular disease at baseline (Multi-Ethnic Study of Atherosclerosis [MESA]), relationships between angiopoietins, cardiac morphology, and subsequent incidence of heart failure or cardiovascular death were evaluated.

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Background: Right ventricular (RV) contractile reserve shows promise as an indicator of occult RV dysfunction in pulmonary vascular disease. We investigated which measure of RV contractile reserve during exercise best predicts occult RV dysfunction and clinical outcomes.

Methods: We prospectively studied RV contractile reserve in 35 human subjects referred for right heart catheterization for known or suspected pulmonary hypertension.

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