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Timothy Joseph McMahon

Professor of Medicine
Medicine, Pulmonary, Allergy, and Critical Care Medicine
DUMC 2650, 203 Research Drive, Durham, NC 27710
MSRB1, Rm 275, DUMC 2650, 203 Research Drive, Durham, NC 27710

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.

Current Appointments & Affiliations


Professor of Medicine · 2021 - Present Medicine, Pulmonary, Allergy, and Critical Care Medicine, Medicine

Recent Publications


The 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 Cite

Endothelial 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 Cite
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Recent Grants


Red blood cell ATP export and transfusion in sepsis (R01)

ResearchPrincipal Investigator · Awarded by National Heart, Lung, and Blood Institute · 2023 - 2026

Duke 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 - 2026

Novel Mechanisms and Therapeutic Targets for Pulmonary Hypertension in End-Stage Renal Disease (K23)

ResearchCo-Mentor · Awarded by National Institutes of Health · 2021 - 2026

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Education, Training & Certifications


Tulane University · 1993 M.D.
Tulane University · 1992 Ph.D.