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Hypertension and COVID-19 is a dangerous mix: Pre-activated immune cells may be the cause

Researchers were surprised to find that many patients were readmitted with a new diagnosis of Type 2 diabetes.

An augmented immune response explains the adverse effects of COVID-19 in patients with hypertension. Could ACE inhibitors offer protection?

Written by Jahnavi Sarma |Updated : January 13, 2021 9:37 AM IST

High blood pressure, or hypertension, is a common condition that affects more than a billion people across the world. According to estimates, of the more than 75 million people around the world who have become infected with COVID-19 worldwide so far, more than 16 million also have hypertension. COVID-19 patients who also suffer from high blood pressure are more likely to fall severely ill with the disease, which also leaves them at greater risk of death. Researchers from the Berlin Institute of Health (BIH) and Charit -- Universit tsmedizin Berlin, in collaboration with partners in Heidelberg and Leipzig, have now found that the immune cells of patients with hypertension are already pre-activated, and that this pre-activation is greatly enhanced under COVID-19. This most likely explains the augmented response of the immune system and the more severe disease progression.

But there is good news too. Certain hypertension-reducing drugs known as ACE inhibitors can have a beneficial effect. They not only lower blood pressure, but also counteract immune hyperactivation. The journal Nature Biotechnology published this study.

Antihypertensive drugs and effect on COVID patients

Hypertensive patients are more likely to become severely ill, which, in turn, results in an increased risk of death. Till now, though experts knew that this happens, they were not sure why. It was unclear to what extent treatment with antihypertensive drugs could be continued during a SARS-CoV-2 infection or whether such medications were more likely to benefit or harm the patients. This is because anti-hypertensives interfere with the exact same regulatory mechanism that the novel coronavirus SARS-CoV-2 uses to enter the host cell and trigger COVID-19.

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These drugs have an effect on ACE2 receptors used by virus to enter cells

Patients with hypertension or cardiovascular diseases often experienced a particularly critical disease progression with COVID-19. The virus uses the receptor ACE2 as an entry portal into the cells, and the formation of this receptor is potentially influenced by the administration of antihypertensive drugs. Hence, it was initially feared that patients receiving ACE inhibitors or angiotensin receptor blockers might have more ACE2 receptors on their cell surfaces and thus become more easily infected.

To clarify this suspicion, researchers analyzed individual cells from the respiratory systems of COVID-19 patients who were also taking medication for high blood pressure. They found that the drugs do not cause more receptors to form on the cells or it easier for the virus to enter the cells. Rather, cardiovascular patients taking ACE inhibitors actually displayed a lower risk of becoming severely ill with COVID-19.

Elevated inflammation in blood of hypertensive patients

The blood of hypertensive patients usually shows elevated levels of inflammation, which can be fatal in the case of COVID-19 infection. Elevated inflammation levels are always a warning signal that COVID-19 will be more severe, regardless of any cardiovascular issues. Researchers therefore employed single-cell sequencing methods to investigate the immune response of hypertensive patients with COVID-19. They analyzed a total of 114,761 cells from the nasopharynx of 32 COVID-19 patients and 16 non-infected controls, with both groups including cardiovascular patients as well as people without cardiovascular problems. They found that the immune cells of the cardiovascular patients displayed strong pre-activation even before infection with the novel coronavirus. After contact with the virus, these patients were more likely to develop an augmented immune response, which was associated with the severe disease progression of COVID-19.

ACE inhibitors can prevent augmented immune response

The results of this study also showed that treatment with ACE inhibitors, though not with angiotensin receptor blockers, could prevent this augmented immune response following infection by the coronavirus. ACE inhibitors could thus reduce the risk of patients with hypertension from experiencing severe disease progression. They also saw that anti-hypertensive drugs can also impact how quickly the immune system is able to reduce the viral load in the body.

(With inputs from IANS)

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