Pathogenesis of dysgeusia in COVID-19 patients: a scoping review.

OBJECTIVE: The novel coronavirus disease-19 (COVID-19) pandemic had intense social and economic effects. Patients infected with COVID-19 may present with a series of conditions. A considerable number of patients express taste and smell disturbances as a prodromal, coexistent, or as the only manifestation of COVID-19 infection. The objective of the present review is to review the hypothetical mechanisms of action and etiopathogenesis of dysgeusia in COVID-19 patients. MATERIALS AND METHODS: Multiple scientific databases were explored, including PubMed, Medline, Scopus, Cochrane-library, LILACS, Livivo and OpenGrey. All types of articles that discussed the pathogenesis of dysgeusia were included, while articles that described dysgeusia without detail about its mode of action were excluded. RESULTS: A total of 47 articles, with different designs, were included in this review. These articles suggested direct viral neural invasion to olfactory and gustatory nerves, viral cytotoxicity to taste buds, angiotensin II imbalance, augmented pro-inflammatory cytokines, and disturbances in salivary glands and sialic acid. COVID-19 induced-dysgeusia was also associated with systemic diseases, medications, zinc, chemicals, and disinfectants. CONCLUSIONS: The most likely cause of transient dysgeusia in COVID-19 is peripheral neurotropism and direct toxicity to taste buds or olfactory epithelium. Other factors may also play a contributory role in dysgeusia, such as a defect in the quality and quantity of saliva, pro-inflammatory cytokines, angiotensin II accumulation, systemic diseases, hypozincemia, and excessive use of chemicals.

Effect of rutin on diabetic-induced erectile dysfunction: Possible involvement of testicular biomarkers in male rats.

The present study aimed to investigate effects of rutin on diabetic-induced impairments of sexual behaviour, spermatogenesis and oxidative testicular damage. Diabetes was induced by a single injection of STZ (65 mg/kg) in male adult Wistar rats. Two weeks later, rutin (50 and 100 mg kg-1  day-1 ) was treated to normal and diabetic rats for 5 weeks. Sexual behaviour of the animals was observed by taking stimulus females. At the end of the study, sperm count, motility and viability were recorded. Serum levels of glucose, inflammatory markers and testosterone were also estimated. In penile tissue, cGMP levels were measured, while lipid peroxidation and antioxidant molecules and enzyme activities were determined. Finally, histopathological changes were evaluated in a cross-section of testis. Diabetic-induced alterations in male sexual behaviour and sperm count, motility and viability were markedly corrected following 5 weeks of rutin treatment to the diabetic animals. Rutin also attenuated the inhibited serum testosterone and penile cGMP content, while improved diabetic-associated inflammation and testicular lipid peroxidation and oxidative stress. Histopathological evaluation revealed damaged testicular tissues in diabetic rats, which was protected following rutin treatment. In conclusion, treatment with rutin improved sexual functionality and also protects against diabetic-induced testicular damage.