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Severe COVID-19 impairs microvascular function

DALLAS – Dec. 08, 2021 – COVID-19 impairs the function of the body’s microvascular system with an intensity that corresponds to the severity of disease, suggests a new study by an international consortium, including UT Southwestern Medical Center.

Photo of David Busch, Ph.D.
David Busch, Ph.D., Assistant Professor of Anesthesiology and Pain Management and Neurology

Developing a better understanding of COVID-19’s impact on individual patients’ microcirculation could lead to personalized therapies as well as better predictions of patient outcomes, explained co-author David Busch, Ph.D., Assistant Professor of Anesthesiology and Pain Management and Neurology at UT Southwestern. The findings, reported in Critical Care, may explain some clinical features of severe COVID-19 and eventually help identify new ways to monitor the course of an infection.

“Our findings reinforce the idea of a systemic microvascular involvement in severe COVID-19 patients,” said Dr. Busch, a member of the international HEMOCOVID-19 consortium led by Turgut Durduran, Ph.D., Professor and Medical Optics Group Leader at ICFO. This group brings together researchers from the U.S., Mexico, Spain, Ireland, Italy, and Brazil to study alterations in tiny blood vessels in COVID-19 patients and the associated consequences for patient outcomes. The Busch lab develops optical technologies for noninvasive and minimally invasive bedside assessment of microvascular blood flow and oxygen saturation, allowing continuous assessment of oxygen metabolism during critical care.

Other UTSW faculty members participating in this consortium include Christopher Choi, M.D., Assistant Professor of Anesthesiology and Pain Management; Siddharth Dave, M.D., Assistant Professor of Anesthesiology and Pain Management; Sreekanth Cheruku, M.D., Associate Professor of Anesthesiology and Pain Management; Peiman Lahsaei, M.D., Assistant Professor of Anesthesiology and Pain Management; and DaiWai Olson, Ph.D., RN, Distinguished Teaching Professor of Neurology and Neurological Surgery.

Although COVID-19 is often considered primarily a respiratory syndrome, several studies have shown it also affects the circulatory system. However, its effect on microcirculation – the movement of blood in the body’s smallest blood vessels that supplies the bulk of oxygen and nutrients to organs and tissues –hasn’t been well characterized, explained Dr. Busch, a Fulbright and Whitaker Scholar.

Using near-infrared spectroscopy, the researchers measured local oxygen saturation and hemoglobin concentration in tissues and blood before and after restricting blood flow. The COVID-19 patients had lower oxygen metabolism saturation and microvascular reactivity after blood flow restriction that corresponded to the severity of their acute respiratory distress syndrome, a key feature of COVID-19 infection. These findings and those from other studies suggest that COVID-19 may damage the endothelium, the lining of blood vessels that controls their dilation and constriction.

Early results from the HEMOCOVID-19 project led to support from both the National Institutes of Health (NIBIB R21EB031261) and EU (Vasocovid) to develop improved instrumentation and analysis.

This study, one of more than 250 COVID-related studies at UTSW, was funded by grants from the CELLEX Foundation of Barcelona, Spain; Mir-Puig Foundation; Barcelona City Hall; State Research Agency (PHOTOMETABO, PID2019-106481RB-C31/10.13039/501100011033); the Severo Ochoa Program for Centers of Excellence in R&D (CEX2019-000910-S); the “La Caixa” Foundation (LlumMedBcn); Government of Catalonia (CERCA, AGAUR-2017-SGR-1380, RIS3CAT-001-P-001682 CECH); and European Commission Horizon 2020 (FEDER, 688303/LUCA, 101016087/VASCOVID, 87114/LASERLAB-EUROPE V). The study authors also acknowledge collaboration and an instrument loan from Artinis (Netherlands).

About UT Southwestern Medical Center

UT Southwestern, one of the nation’s premier academic medical centers, integrates pioneering biomedical research with exceptional clinical care and education. The institution’s faculty has received six Nobel Prizes and includes 25 members of the National Academy of Sciences, 16 members of the National Academy of Medicine, and 14 Howard Hughes Medical Institute Investigators. The full-time faculty of more than 2,800 is responsible for groundbreaking medical advances and is committed to translating science-driven research quickly to new clinical treatments. UT Southwestern physicians provide care in about 80 specialties to more than 117,000 hospitalized patients, more than 360,000 emergency room cases, and oversee nearly 3 million outpatient visits a year.