Overview
The McMahon Lab at Duke University and Durham VA Medical Center is investigating novel roles of the red blood cell (RBC) in the circulation. The regulated release of the vasodilator SNO (a form of NO, nitric oxide) by RBCs within the respiratory cycle in mammals optimizes nutrient delivery at multiple levels, especially in the lung (gas exchange) and the peripheral microcirculation (O2 transport to tissues). Deficiency of RBC SNO bioactivity (as in human RBCs banked for transfusion), for example, appears to contribute to the serious lung and circulatory problems associated with RBC transfusion in some settings. We have also demonstrated benefit in the use of treatments that exploit RBCs as a vehicle for delivery of SNOs, in both human patients and in model animals.
RBCs also release ATP in response to stimuli including deformation and hypoxia, and the exported ATP also participates in the maintenance of a healthy circulation, according to mechanisms that we are now unraveling.
We use basic and translational approaches to understand the molecular mechanisms by which these RBC-derived signals effect circulatory changes in human health and disease, particularly in the lung. Disease states driving this research include acute and chronic lung diseases such as sepsis (severe infection, such as COVID-19), transfusion-related respiratory problems, sickle cell disease, and pulmonary hypertension of adults and newborns.
Funding: VA and NIH.
RBCs also release ATP in response to stimuli including deformation and hypoxia, and the exported ATP also participates in the maintenance of a healthy circulation, according to mechanisms that we are now unraveling.
We use basic and translational approaches to understand the molecular mechanisms by which these RBC-derived signals effect circulatory changes in human health and disease, particularly in the lung. Disease states driving this research include acute and chronic lung diseases such as sepsis (severe infection, such as COVID-19), transfusion-related respiratory problems, sickle cell disease, and pulmonary hypertension of adults and newborns.
Funding: VA and NIH.
Current Appointments & Affiliations
Professor of Medicine
·
2021 - Present
Medicine, Pulmonary, Allergy, and Critical Care Medicine,
Medicine
Recent Publications
Mass spectrometry-based quantification of proteins and post-translational modifications in dried blood: longitudinal sampling of patients with sepsis in Tanzania.
Preprint · April 28, 2025 Full text Link to item CiteThe high price of equity in pulse oximetry: A cost evaluation and need for interim solutions.
Journal Article PLOS Digit Health · September 2024 Disparities in pulse oximetry accuracy, disproportionately affecting patients of color, have been associated with serious clinical outcomes. Although many have called for pulse oximetry hardware replacement, the cost associated with this replacement is not ... Full text Link to item CiteEndothelial LAT1 (SLC7A5) Mediates S-Nitrosothiol Import and Modulates Respiratory Sequelae of Red Blood Cell Transfusion In Vivo.
Journal Article Thromb Haemost · July 2024 BACKGROUND:  Increased adhesivity of red blood cells (RBCs) to endothelial cells (ECs) may contribute to organ dysfunction in malaria, sickle cell disease, and diabetes. RBCs normally export nitric oxide (NO)-derived vascular signals, facilitating blood fl ... Full text Open Access Link to item CiteRecent Grants
Red blood cell ATP export and transfusion in sepsis (R01)
ResearchPrincipal Investigator · Awarded by National Heart, Lung, and Blood Institute · 2023 - 2026Duke Program of Training in Pulmonary ReSearch to Promote, Engage and Retain Academic Researchers (PROSPER)
Inst. Training Prgm or CMEPreceptor · Awarded by National Heart, Lung, and Blood Institute · 2022 - 2026Novel Mechanisms and Therapeutic Targets for Pulmonary Hypertension in End-Stage Renal Disease (K23)
ResearchCo-Mentor · Awarded by National Institutes of Health · 2021 - 2026View All Grants
Education, Training & Certifications
Tulane University ·
1993
M.D.
Tulane University ·
1992
Ph.D.