New perspectives on natural flavonoids on COVID-19-induced lung injuries.

The SARS-CoV-2 virus, responsible for COVID-19, spread rapidly worldwide and became a pandemic in 2020. In some patients, the virus remains in the respiratory tract, causing pneumonia, respiratory failure, acute respiratory distress syndrome (ARDS), and sepsis, leading to death. Natural flavonoids (aglycone and glycosides) possess broad biological activities encompassing antiinflammatory, antiviral, antitumoral, antiallergic, antiplatelet, and antioxidant effects. While many studies have focused on the effects of natural flavonoids in experimental models, reports based on clinical trials are still insufficient. In this review, we highlight the effects of flavonoids in controlling pulmonary diseases, particularly the acute respiratory distress syndrome, a consequence of COVID-19, and their potential use in coronavirus-related diseases. Furthermore, we also focus on establishing a relationship between biological potential and chemical aspects of related flavonoids and discuss several possible mechanisms of action, pointing out some possible effects on COVID-19.

Interleukin-6 and the Gut Microbiota Influence Melanoma Progression in Obese Mice.

There is a strong correlation between obesity and cancer. Here, we investigated the influence of IL-6 and gut microbiota of obese mice in melanoma development. We first evaluated B16F10 melanoma growth in preclinical models for obesity: mice deficient for leptin (ob/ob) or adiponectin (AdpKO) and in wild-type mice (WT, C57BL/6J) fed a high-fat diet (HFD; 60% kcal from fat) for 12 weeks. The survival rates of ob/ob and HFD-fed mice were lower than those of their respective controls. AdpKO mice also died earlier than WT control mice. We then verified the involvement of IL-6 signaling in obese mice that were inoculated with melanoma cells. Both ob/ob and AdpKO mice had higher circulating IL-6 levels than wild-type mice. Melanoma tumor volumes in IL-6 KO mice fed an HFD were reduced compared to those of WT mice subjected to the same diet. Also evaluated the effect of microbiota in tumor development. Cohousing and fecal matter transfer experiments revealed that microbiota from ob/ob mice can stimulate tumor development in lean WT mice. Taken together, our data show that in some conditions IL-6 and the gut microbiota are key mediators that link obesity and melanoma.

Metformin exerts antitumor activity via induction of multiple death pathways in tumor cells and activation of a protective immune response.

The antitumor effect of metformin has been demonstrated in several types of cancer; however, the mechanisms involved are incompletely understood. In this study, we showed that metformin acts directly on melanoma cells as well as on the tumor microenvironment, particularly in the context of the immune response. In vitro, metformin induces a complex interplay between apoptosis and autophagy in melanoma cells. The anti-metastatic activity of metformin in vivo was assessed in several mouse models challenged with B16F10 cells. Metformin's activity was, in part, immune system-dependent, whereas its antitumor properties were abrogated in immunodeficient (NSG) mice. Metformin treatment increased the number of lung CD8-effector-memory T and CD4+Foxp3+IL-10+ T cells in B16F10-transplanted mice. It also decreased the levels of Gr-1+CD11b+ and RORγ+ IL17+CD4+ cells in B16F10-injected mice and the anti-metastatic effect was impaired in RAG-1-/- mice challenged with B16F10 cells, suggesting an important role for T cells in the protection induced by metformin. Finally, metformin in combination with the clinical metabolic agents rapamycin and sitagliptin showed a higher antitumor effect. The metformin/sitagliptin combination was effective in a BRAFV600E/PTEN tamoxifen-inducible murine melanoma model. Taken together, these results suggest that metformin has a pronounced effect on melanoma cells, including the induction of a strong protective immune response in the tumor microenvironment, leading to tumor growth control, and the combination with other metabolic agents may increase this effect.

An open randomized study comparing immunosuppression therapy initiated before or after kidney transplantation in haploidentical living recipients.

BACKGROUND: Acute rejection is the most important risk factor for graft survival. Although many centers start immunosuppressive therapy days before the surgery in living donors, there is no systematic study concerning the possible advantages of this procedure. In this open randomized study, we compared the efficacy and safety of administration of cyclosporine (CSA; Neoral) and azathioprine before renal transplantation with the administration of the same schema after transplantation, in HLA haploidentical grafts. METHODS: Sixty renal transplant recipients of an HLA haploidentical allograft from living donors were randomized in two groups: (A) patients that started immunosuppression 3 d before transplantation (n = 30) and (B) those who started the drug schema on the first day after surgery (n = 30). We analyzed the incidence and severity of acute rejection, graft function and infection during the first 3 months after transplantation. RESULTS: The group of patients who started immunosuppression before had a mean trough level of CSA (299.70 +/- 154.03 ng/mL) in the expected range for an efficacious prevention of acute rejection at the surgery day. Thirteen patients (43.3%) in each group had acute rejection during the follow up (p = 1.00). Two grafts losses (3.3%) occurred, one in each group. Both groups had similar 3-month rejection-free graft survival (56.7 and 56.3%). The incidence of infection was also statistical comparable between groups A and B (56.7 vs. 46.7, p = 0.430). Graft function was similar in patients from both groups. CONCLUSIONS: Pre-transplant administration of immunosuppression did not reduce the incidence or severity of acute rejection episodes during the first 3 months of transplantation. Immunosuppressive drugs administered before engraftment did not increase the incidence of graft dysfunction or infection.