Biology subjects

Hemnes, A. R.

Publications and source records attributed to Hemnes, A. R..

3 recordsLinked to original sources

bioRxiv2025

Reducing Reactive Lipids Improves Cardiac Metabolic and Diastolic Function in Pulmonary Hypertension Models

BackgroundReactive oxygen species are increased across most pulmonary hypertension (PH) etiologies, resulting in increased reactive lipid dicarbonyls, which form protein adducts and impair mitochondrial function. We hypothesized that reducing reactive lipids would reduce right ventricular systolic pressure (RVSP) and improve cardiac function by eliminating protein-lipid damage feedback loops. MethodsWe used 2-hydroxybenzylamine (2-HOBA) to scavenge reactive lipids in three complimentary mouse models of PH: AKR-high fat diet (HFD, metabolic stress), LNAME-HFD (cardiometabolic syndrome), and pulmonary artery banding (PAB, load stress). Cardiac function was measured by echocardiography and catheterization. RV energy metabolism was determined by oxygraphy. Mass spectrometry analyzed lipids and ceramides; O-link and RNA-Seq evaluated proteomic and gene expression in lungs, RV, and LV. ResultsReducing reactive lipids with 2-HOBA resulted in a [~]10% reduction in RVSP, reduced diastolic dysfunction, reduced plasma lipids and ceramides, and normalized RV fatty acid oxidation that was severely impaired in the AKR-HFD and PAB models. Proteomic and RNA changes in the lungs, RV, and LV suggested reduced oxidative damage and inflammatory signaling and altered developmental and actin organization signaling; these changes are plausibly associated with the improved adaptation. Some changes were sex specific, including a 4x higher cardiac fatty acid content in males than females. ConclusionsReactive lipid scavenging improves cardiac metabolic and diastolic function and pulmonary vascular resistance through restoration of mitochondrial function and reduced oxidative protein damage. The magnitude of hemodynamic improvement combined with substantial diastolic function improvement suggests clinical potential, particularly for PH patients with metabolic comorbidities.

molecular biology↗

bioRxiv2024

Pulmonary primary oxysterol and bile acid synthesis as a predictor of outcomesin pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a rare and fatal vascular disease with heterogeneous clinical manifestations. To date, molecular determinants underlying the development of PAH and related outcomes remain poorly understood. Herein, we identify pulmonary primary oxysterol and bile acid synthesis (PPOBAS) as a previously unrecognized pathway central to PAH pathophysiology. Mass spectrometry analysis of 2,756 individuals across five independent studies revealed 51 distinct circulating metabolites that predicted PAH-related mortality and were enriched within the PPOBAS pathway. Across independent single-center PAH studies, PPOBAS pathway metabolites were also associated with multiple cardiopulmonary measures of PAH-specific pathophysiology. Furthermore, PPOBAS metabolites were found to be increased in human and rodent PAH lung tissue and specifically produced by pulmonary endothelial cells, consistent with pulmonary origin. Finally, a poly-metabolite risk score comprising 13 PPOBAS molecules was found to not only predict PAH-related mortality but also outperform current clinical risk scores. This work identifies PPOBAS as specifically altered within PAH and establishes needed prognostic biomarkers for guiding therapy in PAH. One-Sentence SummaryThis work identifies pulmonary primary oxysterol and bile acid synthesis as altered in pulmonary arterial hypertension, thus establishing a new prognostic test for this disease.

systems biology↗

bioRxiv2023

Myeloid Cell-Derived IL1β Contributes to Pulmonary Vascular Remodeling in Heart Failure with Preserved Ejection Fraction

BackgroundPulmonary hypertension (PH) in heart failure with preserved ejection fraction (HFpEF) is a common and highly morbid syndrome, but mechanisms driving PH-HFpEF are not well understood. We sought to determine whether a well-accepted murine model of HFpEF also displays features of PH in HFpEF, and we sought to identify pathways that might drive early remodeling of the pulmonary vasculature in HFpEF. MethodsEight week old male and female C57/BL6J mice were given either L-NAME and high fat diet (HFD) or control water/diet for 2,5, and 12 weeks. Bulk RNA sequencing and single cell RNA sequencing was performed to identify early and cell-specific pathways that might regulate pulmonary vascular remodeling in PH-HFpEF. Finally, clodronate liposome and IL1{beta} antibody treatments were utilized to deplete macrophages or IL1{beta}, respectively, to assess their impact on pulmonary vascular remodeling in HFpEF. ResultsMice given L-NAME/HFD developed PH, small vessel muscularization, and right heart dysfunction after 2 weeks of treatment. Inflammation-related gene ontologies were over-represented in bulk RNA sequencing analysis of whole lungs, with an increase in CD68+ cells in both murine and human PH-HFpEF lungs. Cytokine profiling of mouse lung and plasma showed an increase in IL1{beta}, which was confirmed in plasma from patients with HFpEF. Single cell sequencing of mouse lungs also showed an increase in M1-like, pro-inflammatory populations of Ccr2+ monocytes and macrophages, and transcript expression of IL1{beta} was primarily restricted to myeloid-type cells. Finally, clodronate liposome treatment prevented the development of PH in L-NAME/HFD treated mice, and IL1{beta} antibody treatment also attenuated PH in L-NAME/HFD treated mice. ConclusionsOur study demonstrated that a well-accepted model of HFpEF recapitulates features of pulmonary vascular remodeling commonly seen in patients with HFpEF, and we identified myeloid cell derived IL1{beta} as an important contributor to PH in HFpEF.

cell biology↗