Andrey Kiyasov, Vice-Rector for Biomedicine, Director of the Institute of Fundamental Medicine and Biology, gave comments to a local online news portal.
On KFU’s research in COVID vaccine
At KFU, efforts are actively being made to create a vaccine against coronavirus. The vaccine itself at our institute will be received in May, and preclinical studies on mice will be conducted until August. But you must understand that even if the vaccine appears tomorrow, it will not help cure the existing patients. The humankind is faced with a completely new infection. Someone will get sick and gain immunity. I hope that most of us will dodge this virus. But it will not disappear altogether. That’s it, the virus has arrived; it has come for a long time and will be circulating among people! There will be those in whom the virus will exist without causing the disease, and these people will periodically “throw” it into the surrounding space. Therefore, to prevent a large-scale outbreak of the infection in the future, a vaccine is needed. Humanity is aging, the number of people at risk is increasing. We need measures not of hygienic and biological prevention.
On possible COVID medications
The strategy for finding drugs for the treatment and prevention of coronavirus infection is multi-pronged.
The first is vaccine development.
The second – the search for a way to deceive the virus with fake “gates” not on the surface of cells, but around them. Soluble forms of ACE2 (angiotensin-converting enzyme), i.e. “dummies», cause the virus to be distracted by them and reduce the viral load on the cells, thus protecting the lungs.
The third is to try to break not the “gate” itself, but the passage through it. Scientifically, this means the inhibition of serine proteases, that is, proteins through which the virus goes along the path and into the cell, opening the “gate” lock.
The fourth is the development of new ACE2 blockers to combat COVID-19. Here is the most interesting thing. To treat hypertension, people are actively looking for food proteins, that is, proteins in our food that block or inhibit ACE2. About 13 percent of all proteins in a normal chicken egg is ovotransferrin. It is not found in the yolk, but in the protein, and has antibacterial, antiviral and antifungal properties. In addition, it is a food protein blocker of ACE2.
On why SARS-CoV-2 can infect humans
Each virus has its favorite host cells. There are viruses that multiply inside bacteria, and they are called bacteriophages. Inside a multicellular organism, a virus is only interested in particular cells: hepatitis virus multiplies only in liver cells, human immunodeficiency virus – in T-helper lymphocytes. For each virus, the favorite is the cell that has a “gate” through which the virus can enter. For SARS-CoV-2, this gate is ACE2. This enzyme belongs to the renin-angiotensin system that regulates sodium metabolism and blood pressure. Sodium and blood pressure are connected like a thread with a needle. Therefore, one of the recommendations in the fight against cardiovascular disease and hypertension is to reduce the intake of salt, i.e. sodium chloride. Sodium retains water in the body, the volume of circulating blood increases, which means that blood pressure rises.
The renin-angiotensin system works like this. Our ancestors often suffered from injuries and blood loss. Therefore, we needed mechanisms to increase blood pressure after blood loss, so that our ancestor could get to a secluded place and hide from enemies or predators. Near each glomerulus in the kidneys on blood vessels, there are cells that sense sodium concentration and blood pressure. If pressure drops or sodium decreases, the periglomerular cells release the renin enzyme into the bloodstream. Renin breaks down the protein angiotensinogen to angiotensin-1. With blood, angiotensin-1 enters the vessels of the lung, where ACE2 awaits it. Angiotensin-1 then turns in angiotensin-2. Angiotensin-2 has two functions: make the muscle cells of the arteries contract and instruct the adrenal glands to release the hormone aldosterone into the blood. The latter will cause the kidneys to retain sodium in the body. Both mechanisms increase blood pressure.
On why coronavirus causes pneumonia
In the renin-angiotensin system, ACE2 is located on the membrane of the cells lining the blood capillaries of the lungs. But the virus does not get to them. In addition to capillaries, ACE2 is in the cells of the lung alveoli. Alveoli are air-filled sacs through the wall of which an exchange of oxygen and carbon dioxide occurs. In case of infection, two types of alveolar epithelial cells come into contact with air, and therefore with the virus. There is no ACE2 in flat cells. In cubic cells, which produce surfactant, so that the walls of the alveoli do not stick together, there is ACE2. Through this “gate” the coronavirus enters the cubic alveolar cells. When cells die, a “hole” appears in the epithelial wall of the alveoli. Through the hole the blood plasma enters the alveoli, it is filled with liquid, the liquid does not allow air to fill the alveoli, and gas exchange is disrupted. If respiratory failure develops, the ventilator helps fill the patient’s lungs with oxygen until the body itself restores the integrity of the alveolar epithelial lining.
On why senior citizens are the most affected
Here again, everything is connected with the “gate” for the virus. Scientists have shown this on mice. ACE2 occurs not only on cells lining the capillaries and alveoli in the lungs. This protein has been found in the cells of the kidneys, heart, and brain. During intrauterine development, there is a lot of of it in the kidneys, and after birth – in the heart and brain. It appears gradually in the lungs, and in adulthood and advanced age, when its concentration in other organs decreases, in the lungs it increases and reaches maximum levels. When asked why the disease is more severe, I can assume that a set of other diseases collected during life does not contribute to a quick recovery.