Natriuretic peptides ANP and BNP significantly reduced the lungs' ability to clear fluid by suppressing sodium transport channels in lung tissue, with different effects depending on the stage of heart failure.
61% reduction in lung fluid clearanceBNP decreased alveolar fluid clearance from 0.49 to 0.19 mL/h by suppressing sodium transport in lung epithelial cells
What the researchers found
ANP and BNP significantly reduced alveolar fluid clearance (AFC) in isolated rat lungs. The AFC rate dropped from 0.49 ± 0.02 mL/h in control rats to 0.26 ± 0.013 mL/h with ANP treatment and 0.19 ± 0.005 mL/h with BNP treatment.
The mechanism involved downregulation of active sodium transport components in alveolar epithelial cells, including Na+,K+-ATPase and epithelial sodium channels (ENaC). The peptides enhanced ubiquitination and degradation of αENaC through increased levels of Nedd4-2. In compensated congestive heart failure (CHF), ANP further reduced AFC, but in decompensated CHF, ANP partially restored AFC, revealing a stage-dependent role for natriuretic peptides in lung fluid regulation.
Why it matters
Pulmonary edema — fluid in the lungs — is one of the most dangerous complications of heart failure and a leading cause of hospital admissions. Understanding how natriuretic peptides regulate lung fluid clearance could lead to better-targeted treatments that help the lungs clear fluid without causing harmful side effects, particularly in patients with severe decompensated heart failure.
How the study worked
Researchers used an isolated liquid-filled lung model in rats to directly measure alveolar fluid clearance rates. Congestive heart failure was induced using the aortocaval fistula model in Sprague-Dawley rats. The expression of natriuretic peptides, Na+,K+-ATPase, sodium channels, and the ubiquitin ligase Nedd4-2 was assessed in alveolar epithelial cells. AFC was measured in sham controls, ANP-treated, BNP-treated, compensated CHF, and decompensated CHF groups.
What this study cannot tell us
This is an animal study using rats, and findings may not directly translate to human lung physiology. The aortocaval fistula model of heart failure does not perfectly replicate all forms of human CHF. The isolated lung model, while useful for measuring fluid clearance, removes the lungs from the context of whole-body circulation and hormonal regulation. Specific sample sizes per group are not reported in the abstract. Long-term effects of natriuretic peptide manipulation on lung function were not assessed.
How to read the evidence
This is a preclinical animal study using an established rat model of heart failure. It provides mechanistic data with clear quantitative results, but has not been validated in human subjects. The evidence is strong for basic science understanding but preliminary for clinical application.
When this study was published
Published in 2025, this is very recent research that adds to the current understanding of natriuretic peptide biology in the context of heart failure and pulmonary edema.
The bigger picture
Natriuretic peptides like ANP and BNP are already used clinically as biomarkers for heart failure severity, and synthetic BNP (nesiritide) has been used therapeutically. This study reveals a previously underappreciated effect of these peptides on lung fluid balance, which could explain why some heart failure patients develop pulmonary edema despite treatment. The finding that ANP partially restores fluid clearance in decompensated CHF suggests natriuretic peptide signaling shifts as heart failure progresses, opening the door to stage-specific therapeutic strategies.
Questions still open
- Could blocking natriuretic peptide signaling in the lungs specifically help prevent pulmonary edema in compensated heart failure patients?
- What triggers the switch from ANP reducing fluid clearance in compensated CHF to partially restoring it in decompensated CHF?
- Do existing natriuretic peptide-based therapies like nesiritide inadvertently impair lung fluid clearance in some patients?
Common questions
What are natriuretic peptides and what do they normally do?
Why would peptides that help remove fluid from the body also impair fluid clearance in the lungs?
Read the original research
The Effects of the Natriuretic Peptide System on Alveolar Epithelium in Heart Failure.
International journal of molecular sciences, 26(7)
Citation
Knany, Yara; Kinaneh, Safa; Khoury, Emad E; Zohar, Yaniv; Abassi, Zaid; Azzam, Zaher S. (2025). The Effects of the Natriuretic Peptide System on Alveolar Epithelium in Heart Failure.. International journal of molecular sciences, 26(7). https://doi.org/10.3390/ijms26073374