Preprint Article Version 1 Preserved in Portico This version is not peer-reviewed

Pulmonary Vascular Responses to Chronic Intermittent Hypoxia in a Guinea Pig Model of Obstructive Sleep Apnea

Version 1 : Received: 17 April 2024 / Approved: 18 April 2024 / Online: 19 April 2024 (03:30:21 CEST)

How to cite: Olea, E.; Valverde-Perez, E.; Docio, I.; Prieto-Lloret, J.; Aaronson, P.I.; Rocher, A. Pulmonary Vascular Responses to Chronic Intermittent Hypoxia in a Guinea Pig Model of Obstructive Sleep Apnea. Preprints 2024, 2024041277. https://doi.org/10.20944/preprints202404.1277.v1 Olea, E.; Valverde-Perez, E.; Docio, I.; Prieto-Lloret, J.; Aaronson, P.I.; Rocher, A. Pulmonary Vascular Responses to Chronic Intermittent Hypoxia in a Guinea Pig Model of Obstructive Sleep Apnea. Preprints 2024, 2024041277. https://doi.org/10.20944/preprints202404.1277.v1

Abstract

Experimental evidence suggests that chronic intermittent hypoxia (CIH), a major hallmark of obstructive sleep apnea (OSA), boosts carotid body (CB) responsiveness, thereby causing in-creased sympathetic activity, arterial and pulmonary hypertension, and cardiovascular disease. An enhanced circulatory chemoreflex, oxidative stress, and NO signaling appear to play im-portant roles in these responses to CIH in rodents. Since the guinea pig has a hypofunctional CB (i.e., it is a natural CB knockout), in this study we used it as a model to investigate the CB de-pendence of the effects of CIH on pulmonary vascular responses, including those mediated by NO, by comparing them with those previously described in the rat. We have analyzed pulmonary artery pressure (PAP), the hypoxic pulmonary vasoconstriction (HPV) response, endothelial function both in vivo and in vitro, and vascular remodeling (intima-media thickness, collagen fiber content, and vessel lumen area). We demonstrate that 30 days of exposure of guinea pigs to CIH (FiO2, 5% for 40 s, 30 cycles/h) induces pulmonary artery remodeling but does not alter en-dothelial function or the contractile response to phenylephrine in these arteries. In contrast, CIH exposure increased the systemic arterial pressure, and enhanced the contractile response to phenylephrine while decreasing endothelium-dependent vasorelaxation to carbachol in the aorta, without causing its remodeling. We conclude that since all of these effects are independent of CB sensitization, there must be other oxygen sensors, beyond the CB, with the capacity to alter the autonomic control of the heart and vascular function and structure in CIH.

Keywords

Systemic and pulmonary hypertension; intermittent hypoxia; hypoxic pulmonary vasoconstriction; carotid body; autonomic nervous system; obstructive sleep apnea; endothelial function; vessel remodeling; guinea pig

Subject

Medicine and Pharmacology, Anatomy and Physiology

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