PB1363 - Red-light exposure reduces venous thrombosis in mice

Tuesday, July 12, 2022

6:30 PM – 7:30 PM

Location: Exhibition

Presentation Format: In-Person

Co-Author(s)

EA

Elizabeth A. Andraska

Vascular Surgery Integrated Resident
University of Pittsburgh
Pittsburgh, Pennsylvania, United States
CK

Christof Kalenmeier

General Surgery Resident
University of Pittsburgh
Pittsburgh, Pennsylvania, United States
AA

Aishwarrya Arivudainambi

Medical Student
University of Pittsburgh Medical School
Pittsburgh, Pennsylvania, United States
EM

Emily Mihalko

Postdoctoral Fellow
University of Pittsburgh
Pittsburgh, Pennsylvania, United States
MD

Mitchell Dyer

Fellow
University of Pittsburgh
Pittsburgh, Pennsylvania, United States
Susan M. Shea, MSME, PhD

Assistant Professor
Trauma and Transfusion Medicine Research Center, Department of Surgery and Department of Bioengineering, University of Pittsburgh
Pittsburgh, Pennsylvania, United States
RS

Richard A. Steinman

Associate Professor
Department of Surgery, University of Pittsburgh
Pittsburgh, Pennsylvania, United States
MR

Matthew Rosengart

Professor
University of Pittsburgh
Pittsburgh, Pennsylvania, United States

Presenting Author(s)

Matthew D. Neal, MD

Associate Professor
University of Pittsburgh
Pittsburgh, Pennsylvania, United States

Background: Recent evidence suggests a link between venous thromboembolism (VTE) development and activation of the innate immune system. Studies suggest that light therapy, or photobiomodulation, augments immunity.

Aims: Develop a novel VTE prophylactic strategy utilizing photobiomodulation.

Methods: WT C57BL/6J mice were exposed to ambient (n=13, fluorescent white light, 300 lux), red (n=13, 617nm, 1,700 lux), and blue (n=13, 421nm, 1,700 lux) light with 12:12h light:dark cycle. After 72h light exposure, mice underwent a model of VTE that includes ligation of the inferior vena cava. Thrombus and blood samples were harvested for analysis. Platelet aggregation and activation (CD41+/CD62P+) were evaluated. Platelet releasate was isolated and neutrophil extracellular trap formation (NETosis) was measured. Groups were compared with parametric (mean±SD, t-test) or non-parametric tests (median[interquartile range], Mann-Whitney test) depending on distribution of data. Patients undergoing cataract surgery with implantation of blue-light filtering intraocular lenses (IOL) versus Natural IOL were evaluated for risk of VTE using multivariable logistic regression clustered by hospital.

Results: Red-light exposure markedly reduced clot weight compared to ambient- and blue-light exposed mice (ambient 21[13-23]mg, red 2[0-7.75]mg, blue 21[18-29]mg; p<.01, Fig 1). Red-light exposed mice had reduced levels of platelet aggregation (ambient 17.5±3.4ohm vs. red 5.0±1.5ohm; p=.02) and activation (CD62P+: ambient 77.6±5.0% vs. red 61.8±1.8%; p=.02). NETs were reduced in clots from red-light exposed animals compared to blue and white. Platelet releasate from these animals resulted in reduced NETosis (fold-increase from baseline: ambient 1.9±0.1 vs. red 1.1±0.1, p=.03). In a risk adjusted analysis, blue-light filtering IOL were associated with reduced risk of VTE (OR 0.89; 95% CI 0.80-0.99; p=.04).

Conclusion(s): Exposure to red-light reduced thrombus burden in a murine model of VTE. Reduced platelet activation and stimulation of neutrophils may be integral to reduce thrombosis. Human cataract patients display reduced VTE after unmasking the benefit of red-light. Photobiomodulation is potentially a promising alternative for VTE prophylaxis.