BRIEF RESEARCH REPORT article
Front. Physiol.
Sec. Autonomic Neuroscience
Hypoxic responsiveness and gut fermentation capacity in heart failure patients: preliminary results
Provisionally accepted
Aleksandra Mikołajczak1,2
Rafał Seredyński1
Marzena Gonerska1Mateusz Sokolski2
Bartłomiej Paleczny1*Beata Ponikowska1- 1Department of Physiology and Pathophysiology, Wroclaw Medical University, Wroclaw, Poland
- 2Institute of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
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Background. The gut microbiota has emerged as a key contributor to cardiovascular regulation. Acute stimulation of microbial fermentation with lactulose enhances hypoxic ventilatory response (HVR) in healthy subjects, indicating increased peripheral chemoreceptor (PCh) responsiveness. Given that heart failure (HF) is characterized by PCh hyperactivity, this study investigated whether enhancing intestinal fermentation could acutely modify chemoreceptor-driven responses in HF patients. Methods. HF patients (n=12; all males; age: 59.2[15.8]y; 67% in NYHA III) underwent transient hypoxia test twice: before and ~120 minutes after ingesting a gut-fermentation-stimulating meal. Hydrogen in expired air was measured repeatedly and used to stratify the patients into high early fermentation (HEF) and low early fermentation (LEF) groups. Ventilatory (HVR) and cardiovascular (heart rate, blood pressure, systemic vascular resistance) responses to hypoxia were measured. Results. HEF patients, as compared with the LEF group, displayed: (1) higher pre-lactulose HVR (mean±SD, L/min/SpO2: 0.680±0.284 vs. 0.343±0.122; p=0.024), (2) pre- and post-lactulose SVR response (mean±SD, dyn s/cm5/SpO2: for pre-lactulose comparison, 35.40±24.41 vs. 9.96±1.80, p=0.039; for post-lactulose comparison, 37.19±25.75 vs. 9.22±4.33, p=0.026). HVR in the HEF group correlated with the net hydrogen excretion during the lactulose test (r=0.85, p=0.033). Conclusions. Our preliminary results, derived from a small, uncontrolled physiological experiment conducted in 12 HF patients, imply a link between the upper gut microbial fermentation capacity and the baseline peripheral chemoreflex sensitivity in this population. Given the exploratory and non-randomized design, these findings should be interpreted with caution, and larger controlled studies are needed to confirm the nature and clinical relevance of this association.
Keywords: Gut Microbiota, Heart Failure, Hydrogen Breath Test, Peripheral chemoreceptors, transient hypoxia test
Received: 20 Oct 2025; Accepted: 17 Dec 2025.
Copyright: © 2025 Mikołajczak, Seredyński, Gonerska, Sokolski, Paleczny and Ponikowska. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Bartłomiej Paleczny
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