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Lung microvascular rarefaction impairs pulmonary gas exchange and exacerbates heart failure with preserved ejection fraction

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Title:Lung microvascular rarefaction impairs pulmonary gas exchange and exacerbates heart failure with preserved ejection fraction
Creators: Koçana, Ceren ORCID logoORCID: https://orcid.org/0000-0001-5863-2447, Jaeschke, Lara ORCID logoORCID: https://orcid.org/0009-0004-1847-5378, Chitroceanu, Alexandra Maria, Zhang, Qi ORCID logoORCID: https://orcid.org/0009-0004-5758-6345, Hegemann, Niklas ORCID logoORCID: https://orcid.org/0000-0002-2898-0798, Sang, Pengchao, Li, Qiuhua, Kucherenko, Mariya M. ORCID logoORCID: https://orcid.org/0000-0002-8637-2037, Kräker, Kristin ORCID logoORCID: https://orcid.org/0000-0002-4032-5382, Franz, Kristina, Melnikov, Alexandr ORCID logoORCID: https://orcid.org/0009-0003-4892-6558, Faidel, David ORCID logoORCID: https://orcid.org/0000-0001-9606-9595, von der Ohe, Leonardo Axel, Perret, Paul-Lennard, Gillan, Jonathan L., Winkler, Annika, Reynolds, Edwardo, Kind, Andreas ORCID logoORCID: https://orcid.org/0000-0002-8847-5574, Kretzler, Lucie, Zurkan, Daniela, Zach, Veronika, Tharakan, Samuel Mathew, Hashmi, Mohammad Amiruddin, Berdiev, Bakhrom K., Al Heialy, Saba, Uddin, Mohammed, Knosalla, Christoph ORCID logoORCID: https://orcid.org/0000-0002-8127-5019, Edelmann, Frank, Dechend, Ralf ORCID logoORCID: https://orcid.org/0000-0001-6636-3080, Schiattarella, Gabriele G. ORCID logoORCID: https://orcid.org/0000-0002-7582-7171, Simmons, Szandor ORCID logoORCID: https://orcid.org/0000-0002-5309-9863, Brandenberger, Christina, Grune, Jana ORCID logoORCID: https://orcid.org/0000-0001-6209-7416 and Kuebler, Wolfgang M. ORCID logoORCID: https://orcid.org/0000-0003-4100-2961
Abstract:BACKGROUND: Dyspnea and exercise intolerance are the primary clinical symptoms of heart failure. Heart failure patients experience frequent hypoxemic episodes, yet underlying mechanisms and relevance remain poorly understood. In a cohort of heart failure patients and multiple animal models, we identify pulmonary capillary rarefaction driven by excessive autophagy in endothelial cells as a novel mechanism of hypoxemia and cardiac disease progression. METHODS: A cohort of heart failure with preserved ejection fraction (HFpEF) patients was analyzed for parameters of left ventricular (LV) dysfunction and pulmonary gas exchange. Morphological and cellular mechanisms of impaired pulmonary oxygenation were assessed in three animal models of heart failure, namely two HFpEF models, SU5416-treated ZSF1 obese rats and high fat diet/L-NAME treated mice, and in rats subjected to aortic banding. Lung microvascular rarefaction was quantified by micro-computed tomography, stereology, flow cytometry and dye efflux. Cellular mechanisms of capillary loss were analyzed by single-cell transcriptomics, electron microscopy and immunofluorescence, and in mice with endothelial-specific deletion of the autophagy gene Atg7 (Atg7(EN-KO)). RESULTS: In 234 HFpEF patients, advancing NYHA class was associated with progressive worsening of arterial oxygen saturation at rest and during exercise and a reduced lung diffusing capacity. Impaired gas diffusion correlated with indices of LV diastolic dysfunction. Impaired oxygenation and reduced exercise capacity were similarly evident in animal models of left heart disease, which showed a distinct loss of pulmonary microvessels and capillaries. Lung microvascular endothelial cells in HFpEF showed characteristics of increased autophagic flux and apoptosis. Relative to their wild type HFpEF controls, Atg7(EN-KO) mice had less capillary loss, restored normoxemia, improved exercise tolerance, and mitigated LV diastolic dysfunction. Additional studies in HFpEF mice corroborated the functional relevance of impaired gas exchange for the progression of left heart disease by demonstrating that additional hypoxia aggravated, whereas moderate hyperoxia improved LV function. CONCLUSION: Our findings identify pulmonary microvascular rarefaction as a novel pathomechanism in heart failure that i) contributes to dyspnea and exercise intolerance, ii) impairs pulmonary gas exchange and iii) accelerates LV disease progression. Strategies targeting this axis such as moderate oxygen therapy may mitigate cardiopulmonary morbidity in heart failure. CLINICAL REGISTRATION: Registered in the DRKS (Deutsches Register für klinische Studien) as trial #DRKS00032974 at https://drks.de/search/en/trial/DRKS00032974.
Keywords:Heart Failure, HFpEF, Gas Exchange, Capillary Rarefaction, Autophagy, Apoptosis, Hypoxia, Hyperoxia, Animals, Mice
Source:bioRxiv
Publisher:Cold Spring Harbor Laboratory Press
Article Number:2026.03.05.709974
Date:9 March 2026
Official Publication:https://doi.org/10.64898/2026.03.05.709974
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