Unique protein in placenta could hold key to protecting organs from Covid infection

From enzyme that increases risk of infection to immune system's blood clotting mechanism, ThePrint brings the latest research on Covid-19.

Mothers of newborn babies waiting out side the labour room | Photo: Praveen Jain | ThePrint

New Delhi: With over 2.6 crore cases and more than 8.6 lakh deaths, the coronavirus pandemic continues to rage on across the world. Scientists are also studying the virus and its infection mechanism in detail, to help better manage the disease.

Here are some of the latest findings around the novel coronavirus.

Placenta protein possibly prevents Covid-19 transmission from mother to foetus

Scientists have identified a unique pattern of proteins in placenta tissue that possibly prevents the transmission of Covid-19 from an infected mother to her foetus.

Current data indicates a less than five per cent Covid-19 transmission rate in newborns from their mothers. The study, published in the journal Placenta, shows that the virus invades the placenta in all cases, but results in fetal infection for only some, highlighting the protection placental tissue may offer the foetus.

For this study, the team examined placental tissue, which shares many developmental and physiological similarities with the lung and the immune response of the small and large intestine.

Determining how the placenta prevents Covid-19 infections during pregnancy can help provide clues on how to prevent infection in other organs, such as the lungs and intestines.

Discovery of enzyme that makes co-morbid patients more Covid vulnerable

Scientists claim to have found an enzyme called plasmin that makes people with co-morbidities like hypertension, diabetes and heart disease more vulnerable to Covid-19.

In a study published in the journal Physiological Reviews, researchers noted that plasmin, an extracellular protease, may slightly modify the spike proteins to increase its infectivity and virulence. The spike protein of the novel coronavirus allows it to enter human cells.

Based on the findings, the researchers hypothesise that the plasmin system may prove to be a promising therapeutic target to combat Covid-19.

They also suggest that an inexpensive, commonly used drug — tranexamic acid or TXA — can target plasmin. TXA is already approved by the US Food and Drug Administration for treatment of heavy menstrual bleeding.

The team has already started clinical trials to assess both safety and efficacy of the TXA on Covid-19 patients.

Presence of virus in the blood may predict severe Covid-19

Testing a Covid-19 patient’s blood for the presence or absence of the virus can help identify patients at increased risk of severe forms of the infection, a study shows.

Currently, Covid-19 tests require swabs collected from the nose and throat of a person. The team found that patients without virus in their blood have a good chance of rapid recovery.

The study, published in the scientific journal Clinical Infectious Diseases, reveals that patients with measurable levels of SARS-CoV-2 in their blood were seven times more likely to develop critical symptoms and eight times more likely to die within 28 days.

The researchers analysed the presence of viral RNA in the blood samples taken from a total of 167 patients. Sixty one patients had measurable levels of the virus in their blood and 25 per cent of them died within 28 days of the blood sampling.

This can be compared with the 3 deaths, from the 106 patients, who did not have measurable levels of virus in their blood. The presence of virus in the blood increased with age and was much more common in patients over the age of 60.

Mechanism that causes blood clotting in Covid-19 patients identified

Scientists have identified a protein that triggers a part of the immune system, boosting the blood’s tendency to coagulate and form clots — a finding that may explain why so many Covid-19 patients develop blood clots.

The study, published in Thrombosis and Haemostasis, suggests that activation of what is known as the ‘complement system’ is the key mechanism of clot formation in Covid-19 patients.

This can be initiated by certain proteins such as the mannose-binding lectin (MBL).

The team measured MBL levels and activity in 65 patients receiving intensive care. They found that all those who developed blood clots during their hospital stay had elevated MBL activity and levels.

According to the team, when the complement system is activated by the MBL, it contributes to a massive activation of the blood coagulation system.

The scientists think their results may eventually lead to testing of MBL activity in Covid-19 patients to identify those who are at high-risk of blood clotting. MBL could also be a possible target in future development of drugs to prevent the condition.