Anderson, C. P. | Search bioRxiv

bioRxiv2025

A Doppler Ultrasound Method to Measure Vascular Responses to Walking

Measuring leg blood flow (LBF) in response to walking can offer unique insights regarding mechanical and physiological functions of the leg. However, current gold-standard methods of measuring LBF are invasive. Alternatively, Doppler ultrasound is a promising method to noninvasively measure LBF. The purpose of this study was to demonstrate the utility of a novel ultrasound scanning technique to measure vascular reactivity to walking. Participants walked on a 0{degrees} slope, followed by a -5{degrees} and 5{degrees} slope in random order. A Doppler ultrasound probe was fastened over the dominant-side common femoral artery using a custom 3D printed bracket. LBF was recorded immediately before and after each walking condition. Baseline LBF was not significantly different before each walking condition (p = .577), but there were significant differences in post-walking (p < .001), with uphill causing the greatest increase in LBF. These results suggest that our ultrasound technique is repeatable during quiet standing and can detect the differences in blood flow across different walking intensities. Our method may be valuable to understand how the circulatory system responds to various locomotion tasks, and how cardiovascular disease may impair locomotor functions.

physiology↗

bioRxiv2020

Mucosal-associated invariant T (MAIT) cells mediate protective host responses in sepsis

Sepsis is a systemic inflammatory response to infection and a leading cause of death. Mucosal-associated invariant T (MAIT) cells are innate-like T cells enriched in mucosal tissues that recognize bacterial ligands. We investigated MAIT cells during clinical and experimental sepsis, and their contribution to host responses. In experimental sepsis, MAIT-deficient mice had significantly increased mortality and bacterial load, and reduced tissue-specific cytokine responses. MAIT cells of WT mice expressed lower levels of IFN-{gamma} and IL-17a during sepsis compared to sham surgery, changes not seen in non-MAIT T cells. MAIT cells of patients presenting with sepsis were significantly reduced in frequency, more activated, and had decreased IFN-{gamma} production when stimulated, compared to healthy donors and paired 90-day post-sepsis samples. Our data suggest that MAIT cells are highly activated and become dysfunctional during clinical sepsis, and contribute to tissue-specific cytokine responses that are protective against mortality during experimental sepsis.

physiology↗