Elevated cytokines found in the blood of long COVID sufferers explain heart problems

University of Queensland-led research has found inflammatory markers in the blood of long COVID patients which could explain why many experience ongoing cardiovascular issues.

Associate Professor Kirsty Short said the team set out to investigate the cause of persistent chest pain and heart palpitations commonly reported by many long COVID sufferers.

We discovered elevated levels of cytokines, proteins which help control inflammation in the body, in the blood samples of people at about 18 months post-infection with SARS-CoV-2.

Lab studies showed these trace-level cytokines had a direct effect on the functionality of cardiomyocytes, the cells of the heart responsible for its pump function.

These particular types of cells are fundamental building blocks for our heart, so damaging them can lead to cardiovascular symptoms."

Dr. Kirsty Short, Associate Professor, University of Queensland 

Dr Short said until now, the role of chronic inflammation in cardiovascular symptoms hadn't been clear, particularly in individuals with symptoms persisting for over a year after infection.

The study involved analysing the blood of 50 participants across Australia who had either suffered long COVID for more than a year, had recovered from COVID, or had never had the virus.

The researchers used 'immuno-storm chip' nanotechnology developed at UQ's Australian Institute for Bioengineering and Nanotechnology (AIBN) to discover trace elevated cytokines in the long COVID cohort, along with cardiac tissue damage markers measured at single-molecule resolution in blood.

"It's only early days and these results require validation in additional patient cohorts, including those infected with more recent SARS-CoV-2 strains," Dr Short said.

"We're now curious to know whether our findings could be applied to other symptoms of long COVID such as neurological disease or respiratory disease, as this study actively recruited sufferers with chest pain and/or heart palpitations.

"Despite these limitations, this work offers some important new insights into this complex disease, and hopefully offers opportunities to improve the diagnosis, treatment and understanding of long COVID."

The research was led by UQ PhD candidates Jane Sinclair from the School of Chemistry and Molecular Biosciences (SCMB), Courtney Vedelago from AIBN and Dr Feargal J. Ryan from the South Australian Health and Medical Research Institute.

The research was a collaboration involving UQ's SCMB, School of Mathematics and Physics, AIBN, Institute for Molecular Bioscience and Faculty of Medicine as well as the South Australian Health and Medical Research Institute, Flinders University, the University of Adelaide, the Australian National University, Mater Health Queensland, Mater Research Institute – UQ and QIMR Berghofer Medical Research Institute.

The samples for the research were provided by the COVID OZGenetics study, the Central Adelaide Health Network and the David Serisier Research Biobank at Mater Research.

The research paper was published in Nature Microbiology.