Comhair, Suzy

Background The current classification of pulmonary hypertension (PH), based largely on expert opinion, has limitations in prognostication and guiding therapies. We hypothesize that novel PH clusters that predict survival will reveal mechanistic phenotypes associated with biomarkers of vascular health across all PH groups. Methods We first identify novel PH clinical clusters by performing unsupervised clustering analysis on the CC‐PH (Cleveland Clinic PH) registry (N=1529). We develop classification models to predict the new PH clusters and then apply them to the multicenter PVDOMICS (Pulmonary Vascular Diseases Phenomics) cohort (N=853) for validation. We compare transplantation‐free survival across the new PH clusters. We quantify metabolites of the arginine‐nitric oxide pathway and D‐dimer levels and calculate global arginine bioavailability (arginine/[ornithine+citrulline]) to assess endothelial function and activation in the new clusters and link these biomarkers to clinical outcomes. Results Clustering analysis identify 3 clear clusters in CC ‐ PH that are validated in PVDOMICS and outperform conventional classifications in predicting transplantation‐free survival. The phenotype associated with the worst survival is characterized by reduced lung diffusion capacity, decreased arginine bioavailability and nitrate levels, and elevated D‐dimer levels, consistent with loss of pulmonary microcirculation and endothelial dysfunction. Conclusions We identify new informative PH phenotypes associated with mortality and defined by biomarkers of endothelial function and activation. Loss of endothelial health and pronounced pulmonary vascular rarefication contribute more substantially to mortality across the spectrum of PH than right heart function. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02980887.

BACKGROUND: The metabolic mechanisms underlying right ventricular (RV) dysfunction are poorly understood, particularly outside of group 1 pulmonary hypertension (PH). We aimed to identify metabolites and pathways associated with RV systolic function and explored whether associations differed by pulmonary vascular resistance, PH group 1 status, and sex. METHODS: We analyzed data from the multicenter PVDOMICS (Pulmonary Vascular Disease Phenomics) cohort. RV systolic function metrics included fractional area change (echo), global longitudinal strain (echo), and ejection fraction (cardiac magnetic resonance). We used linear regression adjusted for age, sex, body mass index, and PH group to assess associations between metabolites and RV function. Pathway enrichment analyses were used to identify pathways significantly associated with RV function. Interaction terms were assessed to determine whether metabolite associations were modified by pulmonary vascular resistance, group 1 PH status, or sex. Least absolute shrinkage and selection operator regression was used to develop metabolite-based scores for RV function, and prognostic performance was assessed. RESULTS: There were 979 participants with plasma metabolomics and RV function data. Linear regression identified 170 metabolites that were significantly associated with all 3 RV metrics. Androgenic steroid, gamma-glutamyl amino acid, polyamine, vitamin A, fatty acid, and sterol pathways are most strongly associated with RV systolic function. Two metabolites interacted with group 1 PH status, and 6 interacted with pulmonary vascular resistance. Four androgenic steroids are associated more strongly with RV systolic function in women compared with men. Metabolite-based scores were prognostically equivalent to RV systolic function metrics and less accurate than REVEAL Lite 2 scores. CONCLUSIONS: We provide a blueprint of metabolites and metabolic pathways associated with RV systolic function across the spectrum of PH. Novel links to vitamin A and glutathione metabolites were observed. We detected few metabolites that associated with RV systolic function differentially by group 1 PH status or degree of pulmonary vascular resistance elevation. Androgenic steroids may associate more strongly with RV systolic function in women compared with men.

Abstract Introduction: The airway inflammation of asthma is characterized by immune phenotypes, often classified as Type 2 inflammation high or low. Social determinants of health (SDoH) can influence asthma risk and severity, but whether or not SDoH influence immune phenotypes is unclear. The social deprivation index (SDI) is a composite measure of seven neighborhood level characteristics: poverty level, less than 12 years of education, single parent household, living in rented housing unit, living in overcrowded housing unit, households without a car, and non-employed adults under 65 years of age. The scale of SDI ranges from 1 to 100, correlating with increasing deprivation. We hypothesized that social deprivation influences immune phenotype of asthma, and that deprivation effects vary by sex and race. Methods: Using the American Community Survey summary file spanning 2015 to 2019, we linked SDI to participant zip codes for 680 Black and White participants in the Severe Asthma Research Program (SARP), a NHLBI-multicenter network phenotyping asthma across the US from 2001-2024 (table 1). We compared SDI among the cohort by sex, race and asthma severity, and correlated SDI to superoxide dismutase (SOD) and T2-high biomarkers, such as eosinophils, IgE and Fraction of Exhaled Nitric Oxide (FENO). Results: SDI is similar across healthy and asthmatic participants (SDI: median [interquartile range]: healthy: 40 [56]; asthmatics: 51 [53], P = 0.53). When evaluated by race, SDI is significantly higher in Black asthmatics, independent of sex (SDI: Black male: 76 [4], White male: 35 [45]; P<0.0001; Black females: 77 [35], White females: 40 [45]; P<0.00010). Within SARP asthmatics, SDI shows a positive association with the T2 inflammatory markers, log IgE (R=0.13 [90%CI: 0.1, 0.2)] and log FENO (R=0.15 [90%CI: 0.1, 0.2]), while it correlates negatively with log of absolute neutrophil count (R= -0.12 [90%CI: -0.19,-0.1]). The antioxidant enzyme SOD increases with SDI (R=0.11, [90% CI: 0.04, 0.17]). Notably, within Black asthmatic males only, SDI is associated with Type 2 biomarkers, showing a positive correlation with log FENO (R=0.24 [90%CI: 0.1,0.4]) and negative correlation with log IgE levels (R= -0.25, [90% CI: -0.4, -0.1]). No association was found between SDI and eosinophils or with SOD in Black males. Conclusions: Neighborhood level social deprivation is associated with a unique asthma phenotype in Black males. Black males living at high social deprivation have a lower IgE and higher FENO, with no change in SOD activity.

Our study shows an early increase in kynurenine pathway metabolism in at-risk subjects with systemic sclerosis who develop pulmonary arterial hypertension (PAH). We show that kynurenine pathway upregulation precedes clinical diagnosis and that this metabolic shift is associated with increased disease severity and shorter survival times. We also show that gene expression of TDO2, an enzyme that generates kynurenine from tryptophan, rises with PAH development.

Pulmonary arterial (PA) stiffness is associated with increased mortality in patients with pulmonary hypertension (PH); however, the role of PA stiffening in the pathogenesis of PH remains elusive. Here, we show that distal vascular matrix stiffening is an early mechanobiological regulator of experimental PH. We identify cyclooxygenase-2 (COX-2) suppression and corresponding reduction in prostaglandin production as pivotal regulators of stiffness-dependent vascular cell activation. Atomic force microscopy microindentation demonstrated early PA stiffening in experimental PH and human lung tissue. Pulmonary artery smooth muscle cells (PASMC) grown on substrates with the stiffness of remodeled PAs showed increased proliferation, decreased apoptosis, exaggerated contraction, enhanced matrix deposition, and reduced COX-2–derived prostanoid production compared with cells grown on substrates approximating normal PA stiffness. Treatment with a prostaglandin I 2 analog abrogated monocrotaline-induced PA stiffening and attenuated stiffness-dependent increases in proliferation, matrix deposition, and contraction in PASMC. Our results suggest a pivotal role for early PA stiffening in PH and demonstrate the therapeutic potential of interrupting mechanobiological feedback amplification of vascular remodeling in experimental PH.

Abstract A variety of melanoma antigen A (MAGE-A) genes are commonly detected in non–small cell lung cancers. Their biological function is not well characterized but may involve the regulation of apoptosis and cell cycle progression. We hypothesized that MAGE-A4 is involved in the regulation of apoptosis. To investigate this, expression of MAGE-A was evaluated. MAGE-A4 was expressed in 48% of non–small cell lung carcinomas. Ninety percent of lung carcinomas expressing MAGE-A4 were classified as squamous cell carcinomas and 10% were adenocarcinomas. Tumor-free surrounding lung tissue was negative for MAGE-A4. A molecular clone of MAGE-A4 derived from human lung cancer was stably expressed in human embryonic kidney cells (293 cells) to evaluate effects on cell death. Overexpression of MAGE-A4 increased apoptosis as measured by the apoptotic index (P < 0.0001) and caspase-3 activity (P < 0.002). Exposure to 25 μmol/L etoposide, a chemotherapeutic agent, increased the apoptotic effect (P < 0.0001). Furthermore, we show that MAGE-A4 silencing using a small interfering RNA approach results in decreased caspase-3 activity in the squamous cell lung cancer cell line H1703 by 58% (P = 0.0027) and by 24% (P = 0.028) in 293/MAGE-A4 cells. These findings suggest that MAGE-A4 expression may promote tumor cell death, sensitize malignancies to apoptotic stimuli, such as chemotherapeutic agents, and therefore may represent a tumor suppressor protein. (Cancer Res 2006; 66(9): 4693-700)