High SARS-CoV-2 tropism and activation of immune cells in the testes of non-vaccinated deceased COVID-19 patients.

BACKGROUND: Cellular entry of SARS-CoV-2 has been shown to rely on angiotensin-converting enzyme 2 (ACE2) receptors, whose expression in the testis is among the highest in the body. Additionally, the risk of mortality seems higher among male COVID-19 patients, and though much has been published since the first cases of COVID-19, there remain unanswered questions regarding SARS-CoV-2 impact on testes and potential consequences for reproductive health. We investigated testicular alterations in non-vaccinated deceased COVID-19-patients, the precise location of the virus, its replicative activity, and the immune, vascular, and molecular fluctuations involved in the pathogenesis. RESULTS: We found that SARS-CoV-2 testicular tropism is higher than previously thought and that reliable viral detection in the testis requires sensitive nanosensors or RT-qPCR using a specific methodology. Through an in vitro experiment exposing VERO cells to testicular macerates, we observed viral content in all samples, and the subgenomic RNA's presence reinforced the replicative activity of SARS-CoV-2 in testes of the severe COVID-19 patients. The cellular structures and viral particles, observed by transmission electron microscopy, indicated that macrophages and spermatogonial cells are the main SARS-CoV-2 lodging sites, where new virions form inside the endoplasmic reticulum Golgi intermediate complex. Moreover, we showed infiltrative infected monocytes migrating into the testicular parenchyma. SARS-CoV-2 maintains its replicative and infective abilities long after the patient's infection. Further, we demonstrated high levels of angiotensin II and activated immune cells in the testes of deceased patients. The infected testes show thickening of the tunica propria, germ cell apoptosis, Sertoli cell barrier loss, evident hemorrhage, angiogenesis, Leydig cell inhibition, inflammation, and fibrosis. CONCLUSIONS: Our findings indicate that high angiotensin II levels and activation of mast cells and macrophages may be critical for testicular pathogenesis. Importantly, our findings suggest that patients who become critically ill may exhibit severe alterations and harbor the active virus in the testes.

Neutrophilic infiltration in lungs of mice with peritonitis in acid or basic medium.

BACKGROUND: Bacterial peritonitis is associated with systemic complications such as pneumonia. OBJECTIVE: To determine in an experimental model of peritonitis whether the pH of peritoneal fluid infection influences the influx of neutrophils into the lung, and whether treatment outcome would be similar in peritonitis with liquid at any pH. MATERIALS AND METHODS: We studied 48 mice with peritonitis induced by cecal ligation and puncture. The animals were distributed randomly into three groups: the first one had an injection into the peritoneal cavity with saline, pH 7.0; the second group was injected with saline, pH 8.0; and the third group with saline, pH 3.0. After 2 hours, half the animals in each group was treated by washing the abdominal cavity with warm saline solution and administration of ceftriaxone every 12 hours, and half of each group was killed by anesthetic overdose, and lung biopsy was done. The animals kept in treatment were killed 24 hours after treatment, and lung biopsy was also performed. The samples were stained with H&E and the number of neutrophils in 20 areas was checked. The mean number of cells in each group was compared between groups and with an untreated one. RESULTS: The group with peritonitis associated with alkaline solution showed a higher population of neutrophils during untreated peritonitis (P = 0.04). The response to treatment by lavage of the peritoneal cavity and antibiotics was more effective in reducing the population of neutrophils in the group with peritonitis at pH 8.0, unlike that observed in animals with peritonitis at pH 3.0 (P = 0.03). CONCLUSION: Peritonitis associated with lower pH solution, despite the lower influx of leukocytes in the first two hours after installation of peritonitis, was not able to reduce the population of these cells in mice's lung in response to standard therapy.