Oxidative stress and inflammation in COVID-19: potential application OF GLP-1 receptor agonists.

COVID-19 is a global pandemic with devastating economic and public health impacts, which is particularly associated with increased incidence of respiratory and cardiovascular disease together with inflammation and oxidative stress as essential underlying features. Glucagon-Like Peptide-1 (GLP-1) receptor agonists are now routinely used for the clinical management of type 2 diabetes due to their established glucose-dependent insulinotropic actions. However, these agents also display a variety of pleiotropic functions, including the promotion of anti-inflammatory and antioxidant responses, highlighting likely therapeutic applications beyond glycemic control. Given that COVID-19 is particularly linked with adverse modulation of inflammatory and oxidative signaling, which are known to be impacted by GLP-1 receptor activation, it seems logical that GLP-1 receptor agonists may be beneficial for the clinical management of patients with SARS-CoV-2 infection. In this review, we discuss the specific role of inflammation and oxidative stress associated with COVID-19, including underlying pathogenic mechanisms, as the basis for the potential therapeutic application of GLP-1 receptor agonists to combat both acute and chronic complications of this devastating disease.

Influence of organic matter on the transport of Cryptosporidium parvum oocysts in a ferric oxyhydroxide-coated quartz sand saturated porous medium.

To assess the effect of organic matter on the transport of Cryptosporidium parvum oocysts in a geochemically heterogeneous saturated porous medium, we measured the breakthrough and collision efficiencies of oocysts as a function of dissolved organic matter concentration in a flow-through column containing ferric oxyhydroxide-coated sand. We characterized the surface properties of the oocysts and ferric oxyhydroxide-coated sand using microelectrophoresis and streaming potential, respectively, and the amount of organic matter adsorbed on the ferric oxyhydroxide-coated sand as a function of the concentration of dissolved organic matter (a fulvic acid isolated from Florida Everglades water). The dissolved organic matter had no significant effect on the zeta potential of the oocysts. Low concentrations of dissolved organic matter were responsible for reversing the charge of the ferric oxyhydroxide-coated sand surface from positive to negative. The charge reversal and accumulation of negative charge on the ferric oxyhydroxide-coated sand led to increases in oocyst breakthrough and decreases in oocyst collision efficiency with increasing dissolved organic matter concentration. The increase in dissolved organic matter concentration from 0 to 20mg L(-1) resulted in a two-fold decrease in the collision efficiency.

Effect of ferric oxyhydroxide grain coatings on the transport of bacteriophage PRD1 and Cryptosporidium parvum oocysts in saturated porous media.

To test the effect of geochemical heterogeneity on microorganism transport in saturated porous media, we measured the removal of two microorganisms, the bacteriophage PRD1 and oocysts of the protozoan parasite Cryptosporidium parvum, in flow-through columns of quartz sand coated by different amounts of a ferric oxyhydroxide. The experiments were conducted over ranges of ferric oxyhydroxide coating fraction of lambda = 0-0.12 for PRD1 and from lambda = 0-0.32 for the oocysts at pH 5.6-5.8 and 10(-4) M ionic strength. To determine the effect of pH on the transport of the oocysts, experiments were also conducted over a pH range of 5.7-10.0 at a coating fraction of lambda = 0.04. Collision (attachment) efficiencies increased as the fraction of ferric oxyhydroxide coated quartz sand increased, from alpha = 0.0071 to 0.13 over lambda = 0-0.12 for PRD1 and from alpha = 0.059 to 0.75 over lambda = 0-0.32 for the oocysts. Increasing the pH from 5.7 to 10.0 resulted in a decrease in the oocyst collision efficiency as the pH exceeded the expected point of zero charge of the ferric oxyhydroxide coatings. The collision efficiencies correlated very well with the fraction of quartz sand coated by the ferric oxyhydroxide for PRD1 but not as well for the oocysts.