Faced with a new disease, researchers around the world are striving to understand all its possible impacts on the human body. Regarding Covid-19, there are still many gaps in the knowledge of the mechanisms used by the SARS-CoV-2 virus after infection.
Although it is a respiratory transmitted disease, which mainly affects organs such as the lung, Covid-19 can also cause hormonal changes and inflammation in the testicles. This is what a study conducted by researchers at the University of São Paulo (USP) and published in the scientific journal Andrology reveals.
Researchers have identified that the new coronavirus is capable of invading all types of cells in the testes, causing lesions that can impair hormonal function and male fertility.
To reach the result, specialists performed the autopsy of testicular tissues of 11 patients, aged between 32 and 88 years, who died from complications of Covid-19. The study is coordinated by professors Paulo Saldiva and Marisa Dolhnikoff, from the USP Medical School.
“We saw through electron microscopy that the coronavirus invaded all testis cells. The virus is present in cells that produce sperm, called Sertoli, in cells that produce testosterone, called Leydig, in blood vessels and in the framework that supports the testicle,” explains researcher and andrologist Jorge Hallak, professor at the Faculty of Medicine and coordinator of the Study Group on Men’s Health at the Institute for Advanced Studies at USP.
The analyzes showed a series of lesions, possibly associated with inflammatory changes, which reduce the production of sperm and hormones. The drop in activity may be related to injuries and thrombosis formation, which reduce tissue oxygenation of structures where sperm are produced.
Hormonal and fertility impacts
Another study conducted by the Faculty of Medicine at USP showed that men who had Covid-19 may show changes in the results of hormonal and fertility tests for months after recovery. The results were also published in the journal Andrology.
One of the tests that reveal details of the condition and quality of sperm is the spermogram. The analyzes showed that sperm from patients with Covid-19 had reduced ability to move and fertilize the egg. The index called sperm motility, considered normal above 50%, dropped to a range between 8% and 12%, remaining at this level about a year after infection.
The researchers also found that the new coronavirus is able to infect the testes, which can impact the ability to produce sperm and hormones. According to researcher Jorge Hallak, the results do not allow us to affirm that the men evaluated are infertile. However, the reduction in sperm quality can be a factor that hinders reproduction.
The expert estimates that Covid-19 could cause an increase in male infertility. “My impression as a clinician and andrologist is that Covid-19 will add to other causes of male infertility, such as varicocele, which is varicose veins in the scrotum, the abuse of alcohol, drugs, anabolic steroids and antidepressant medications, which are a major cause of change in testicular function,” says Hallak.
To understand the long-term impacts of the disease on human health, the study is still ongoing, with the continuous assessment of 26 patients treated at USP’s Hospital das Clínicas and at the Androscience Institute of Science and Innovation in Andrology.
From ultrasound examinations, the researchers identified that more than half of the patients had inflammation in the epididymis, which is the structure of the testes that stores sperm and where they gain the ability to move. “We have already identified that sperm alterations can occur due to the coronavirus,” says Hallack.
The USP researcher advises men who have had Covid-19 and wish to have children to undergo medical care to assess the condition of the sperm. “Those who had coronaviruses recently, three or six months ago, should not look for assisted reproduction techniques in the post-Covid acute phase. The use of post-coronavirus testosterone hormone replacement should also be avoided. When you give external testosterone, the body stops producing naturally”, he explains.
Under normal conditions, the level of testosterone in the male body is 300 to 500 nanograms per deciliter of blood (ng/dL). The researchers found that part of the men evaluated showed a significant reduction in the hormone, ranging from 70 to 80 ng/dL.
According to researcher Jorge Hallack, one of the hypotheses for hormonal reduction is the reduction of Leydig cells, which produce testosterone.