April 26 (UPI) -- Taking a specific type of blood pressure medication increases levels of a protein that helps COVID-19 spread through the body, a study presented Monday during the American Society for Pharmacology and Experimental Therapeutics' annual meeting found.
Mice taking angiotensin converting enzyme, or ACE, inhibitors were found to have higher levels of ACE2, a protein present on the surface of cells that is known to help the virus spread through the body, the researchers said.
It remains unclear, according to the researchers, whether higher ACE2 actually raises the risk for more serious illness from COVID-19.
The findings do, however, line up with previous research on the effects of the medications, study co-author Dr. Hans Ackerman said in a press release.
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"We recommend that patients taking heart medications work with their healthcare providers to manage their medications," said Ackerman, chief of the physiology unit in the Laboratory of Malaria and Vector Research at the National Institute of Allergy and Infectious Diseases.
ACE inhibitors such as enalapril, or Vasotec, and ramipril, or Altace, lower production of the ACE enzyme in the body, which causes blood vessels to dilate, thereby reducing blood pressure.
Angio tensin receptor blockers, or ARBs, such as azilsartan, or Edarbi, and irbesartan, or Avapro, help relax the veins and arteries to lower blood pressure.
For this study, Ackerman and his colleagues treated healthy mice with either the ACE inhibitor lisinopril or the ARB losartan, treating them with one or both drugs, or with a placebo.
The researchers measured levels of ACE2 in the lungs, small intestines, brains and kidneys of the mice, as all of these organs are known to be affected by COVID-19.
After three weeks of treatment, lisinopril broadly raised the level of ACE2 molecules across all four tissues, while losartan raised ACE2 only in the small intestine, they said.
However, rodents given the ARB did not have elevated ACE2, according to the researchers.
For mice that received the placebo, ACE2 levels in the small intestine were 10 times higher than in the kidney and 100 times higher than in the brain or lung, according to the researchers.
Three weeks after treatment stopped, the levels of ACE2 no longer differed among the groups of mice, indicating that discontinuing either blood pressure medication returns ACE2 levels to normal, they said.
Whether heart medications -- including ACE inhibitors and ARBs -- change disease risk and severity for COVID-19 has been an intense ongoing area of debate since the start of the pandemic, the researchers said.
"Thus far, clinical studies have not identified an increase in COVID-19 risk or severity among in people taking these drugs," Ackerman said.
"[Our] results provide a controlled, tissue-specific analysis of the effects of ACE inhibitors, ARB and combination therapy on the levels of ACE2 in healthy mice," he said.
