The Covid 'gender' conundrum: Men are more vulnerable to coronavirus due to high levels of 'gateway' molecule
Gateway molecule enables novel coronavirus to infect healthy cells.
By PTI |
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Study suggests that men may have high blood levels of the gateway molecules.
LONDON: Men have higher blood levels of a molecule that enables the novel coronavirus to infect healthy cells than women, according to a study whose findings may explain why men are more vulnerable to COVID-19 than women.
The study, published in the European Heart Journal, also found that heart failure patients taking drugs such as angiotensin-converting enzyme (ACE) inhibitors, or angiotensin receptor blockers (ARBs), did not have higher concentrations of the coronavirus gateway enzyme ACE2 in their blood.
"Our findings do not support the discontinuation of these drugs in COVID-19 patients as has been suggested by earlier reports," said Adriaan Voors, study co-author from the University of Groningen in the Netherlands.
Earlier studies had suggested that these drugs might increase concentrations of ACE2 in plasma -- the liquid part of blood -- thereby increasing the risk of COVID-19 for cardiovascular patients taking these drugs.
According to the current study, this is not the case, although it looked only at ACE2 concentrations in plasma, not in tissues such as lung tissue.
"ACE2 is a receptor on the surface of cells. It binds to the coronavirus and allows it to enter and infect healthy cells after it is has been modified by another protein on the surface of the cell, called TMPRSS2," Voors said.
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"High levels of ACE2 are present in the lungs and, therefore, it is thought to play a crucial role in the progression of lung disorders related to COVID-19," he added.
In the study, the researchers measured ACE2 concentrations in blood samples taken from two groups of heart failure patients from 11 European countries.
There were 1,485 men and 537 women in the first group, the index cohort, which was designed to test the researchers' hypotheses and research questions.
Then the researchers validated their findings in a second group of 1123 men and 575 women, the validation cohort.
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According to the study, the average age of the participants in the index cohort was 69 years for men, and 75 years for women, and in the validation cohort it was 74 and 76 years, respectively.
The study, published in the European Heart Journal, also found that heart failure patients taking drugs such as angiotensin-converting enzyme (ACE) inhibitors, or angiotensin receptor blockers (ARBs), did not have higher concentrations of the coronavirus gateway enzyme ACE2 in their blood.
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The researchers assessed the number of clinical factors that could play a role in ACE2 concentrations, including the use of ACE inhibitors, a history of chronic obstructive pulmonary disease, and coronary artery by-pass graft.
They found that male sex was the strongest predictor of elevated ACE2 concentrations.
In the index cohort, the scientists said ACE inhibitors were not associated with greater ACE2 plasma concentrations.
In the validation cohort, they said that ACE inhibitors and ARBs were associated with lower ACE2 concentrations.
"To the best of our knowledge, this is the first substantial study to examine the association between plasma ACE2 concentrations and the use of blockers of the renin-angiotensin-aldosterone system in patients with cardiovascular disease," Voors said.
The study, according to the researchers, found no evidence that ACE inhibitors and ARBs were linked to increased ACE2 concentrations in plasma.
"In fact, they predicted lower concentrations of ACE2 in the validation cohort, although we did not see this in the index cohort," Voors said.
Based on the findings, the scientists said the effect of the class of drugs called mineralocorticoid receptor antagonists (MRAs) on ACE2 concentrations is not clear since the weak increase in concentrations in the validation cohort was not seen in the index cohort.
Our findings do not suggest that MRAs should be discontinued in heart failure patients who develop COVID-19.
"They are a very effective treatment for heart failure and the hypothetical effects on viral infection should be weighed carefully against their proven benefits," Voors said.
According to the study, ACE2 is found not only in the lungs, but also the heart, kidneys, and the tissues lining blood vessels, and particularly at high levels in the testes.
The researchers speculate that its regulation in the testes might partially explain higher ACE2 concentrations in men, and why men are more vulnerable to COVID-19.
Citing a limitation of the study, the scientists said they only measured concentrations of ACE2 in plasma, not in tissues, so they cannot be sure that concentrations in the blood are similar to those seen in tissues.
The researchers also said its conclusions are mainly restricted to heart failure patients, and the patients did not have COVID-19.
So they said the study does not provide a direct link between the course of the disease and ACE2 plasma concentrations.
It is the ACE2 in the lung tissues that are thought to be important for viral infection of the lungs, not ACE2 concentrations in the blood, they added.
The World Health Organization (WHO) for the longest time believed that coronavirus cannot infect pets like dogs or cats.
In less than a month, several reports of various animals contracting the diseases made the WHO pause and think about their stance. The reports suggest that this deadly virus can break the species barrier and move around.
WHO's intergovernmental animal health body - World Organisation for Animal Health (OIE) - confirmed that there is a possibility that some animals can get infected through close contact with infected humans.
OIE said that studies are under way to understand the issue better and that it is still too early to say whether pets could be the intermediate host in the transmission of the COVID-19.
While they are urging anyone who has become sick to limit contact with pets, we look at all the animals who contracted the disease from humans.
(Representative Image)
The World Health Organization (WHO) for the longest time believed that coronavirus cannot infect pets like dogs or cats.In less than a month, several reports of various animals contracting the diseas..
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Warning! This might upset all dog lovers out there.
The first animal in the world to test positive for coronavirus was a 17-year-old dog which had to be kept under mandatory quarantine in Hong Kong since February 26. The news got grim when the owner revealed that the canine passed away on March 16 - less than a week after he was declared Covid-19-free and released from the government facility.
He was sent home after testing negative, but it was not clear if the virus was the reason for the animal's death. The 60-year-old owner, who also recovered from her Covid journey after being in quarantine, had refused an autopsy of his pet to determine cause of death.
The Pomeranian had been through five tests and all returned 'weak positive' for the new virus.
The last two tests - carried out on March 12 and 13 - 'proved the dog's samples were negative'.
(Representative Image)
Warning! This might upset all dog lovers out there.The first animal in the world to test positive for coronavirus was a 17-year-old dog which had to be kept under mandatory quarantine in Hong Kong si..
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Days after the death of the world's first animal detected with Covid-19, another case emerged in Hong Kong, again, where a German Shepherd living in the Pok Fu Lam area had tested positive for coronavirus during a screening campaign.
While the dog was asymptomatic, his mixed-breed sibling who was living in the same house had tested negative. Both canines were put under quarantine along with their owner who had tested positive as well.
(Representative Image)
Days after the death of the world's first animal detected with Covid-19, another case emerged in Hong Kong, again, where a German Shepherd living in the Pok Fu Lam area had tested positive for corona..
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During a screening campaign carried out on 17 dogs and eight cats living in contact with people carrying the virus, where two canines tested positive, other pets animals like a cat and three dogs were also placed at the animal keeping facility in Hong Kong.
Apart from the Pomeranian which died, the other three animals - an exotic shorthair cat, a Shiba Inu and a mongrel - were also tested negative for the deadly virus, according to reports.
(Representative Image)
During a screening campaign carried out on 17 dogs and eight cats living in contact with people carrying the virus, where two canines tested positive, other pets animals like a cat and three dogs wer..
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Coronavirus didn't spare the felines. In late March, a pet cat was found infected with Covid-19 in Belgium, and it was believed that it contracted the virus from the people it was living with. The corona cat suffered from transitory respiratory and digestive problems after contracting the infection.
To shock you further, the Chinese researchers from Harbin Veterinary Research Institute revealed in a study that cats are not only susceptible to contracting the deadly virus, but could also pass it on to other cats.
However, the study said that other animals such as dogs (despite two known positive cases worldwide), chicken and pigs weren't susceptible like ferrets and cats.
Back home, in an interesting development, authorities have even warmed up to feline lovers. In Kerala, the High Court on April 6 allowed a permit to a cat owner to drive around town in his car amid lockdown to buy food (seven kg biscuits) for his pets.
(Representative Image)
Coronavirus didn't spare the felines. In late March, a pet cat was found infected with Covid-19 in Belgium, and it was believed that it contracted the virus from the people it was living with. The co..
Read More
Another resident of the cat family, a 4-year-old female Malayan tiger, Nadia, tested positive for the novel coronavirus on April 6. The tigress, who lives at the Bronx Zoo in New York with six other big cats, is said to have contracted the deadly virus by an asymptomatic zoo keeper.
Nadia's sister, Azul, and two Amur tigers had also developed a dry cough and loss of appetite.
This case came as a shocker as this was believed to be the first known case of an animal infected with COVID-19 in the US, raising questions about human-to-animal transmission of the virus.
Another resident of the cat family, a 4-year-old female Malayan tiger, Nadia, tested positive for the novel coronavirus on April 6. The tigress, who lives at the Bronx Zoo in New York with six other ..
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Along with the 4-year-old Nadia, three African lions had also developed a dry cough and decrease in appetite. While they did not contract the virus, it was reported that they were expected to recover soon.
The deep-chested cats were put under veterinary care, and were seen bright, alert and interactive with the zookeepers at the Bronx Zoo in New York.
(Representative Image)
Along with the 4-year-old Nadia, three African lions had also developed a dry cough and decrease in appetite. While they did not contract the virus, it was reported that they were expected to recover..
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