Serum il-18 and rs187238 single nucleotide polymorphism are associated with high-density lipoprotein changes in covid-19 outpatients.

AIM: COVID-19 is an inflammatory disease and its prognosis is associated with cardiovascular risk, which can be associated with changes in lipoprotein metabolism. The single nucleotide polymorphism (SNP) rs187238 of Interleukin (IL)-18 is extensively reported in association with worsening inflammatory and cardiovascular disease (CVD). This study evaluated the association of IL-18 levels and its SNP rs187238 with lipoprotein profile changes in COVID-19 outpatients. METHODS: Observational, analytical, cross-sectional study that evaluated 250 patients with respiratory syndrome, 36% (n = 90) with COVID-19. Serum total cholesterol (TC), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), triglycerides (TG), apolipoproteins A-I and B (Apo A-I and Apo B) and IL-18 levels were determined. Polymorphism genotyping was done by real-time polymerase chain reaction (qPCR). The significance level was p < 0.05. RESULTS: Patients with COVID-19 showed a reduction in TC and HDL-c, without difference in IL-18. HDL-c and LDL-c had a high frequency outside the reference values. There was a negative correlation of IL-18 with HDL-c and a positive correlation with Apo B/Apo A-I ratio. The frequencies of the C (wild) and G (polymorphic) alleles between patients with and without COVID-19 followed the Hardy-Weinberg equilibrium. However, COVID-19 was associated with reduced HDL-c and Apo A-I values in patients with the CC genotype. CONCLUSION: IL-18 levels and its SNP rs187238 were associated with decreased HDL-c and Apo A-I in COVID-19 outpatients.

Effect from dinoponeratoxin M-PONTXDq3a arginine and lysine substituted analogues against Staphylococcus aureus strains.

The growing incidence of methicillin-resistant Staphylococcus aureus (MRSA) infections is associated with increased mortality rates, which has generated interest in the development of antimicrobial peptides (AMP), such as those found in the giant ant Dinoponera quadríceps. In order to improve the net positive charge and the antibacterial activity of the AMP, amino acids with positive side chain single substituted analogues have been proposed, mainly arginine or lysine. The present work aims to study the antimicrobial activity of the analogues of M-PONTX-Dq3a, a 23 amino acid AMP identified in the D. quadriceps venom. M-PONTX-Dq3a[1-15], a fragment containing the 15 central amino acids, and eight derivatives of single arginine or lysine substituted analogues were proposed. The antimicrobial activity of peptides was evaluated against Staphylococcus aureus ATCC 6538 P (MSSA) and ATCC 33591 (MRSA) strains, followed by minimum inhibitory concentration (MIC), minimum lethal concentration (MLC), and minimum biofilm inhibitory concentration (MBIC) measurement. The membrane permeability was then assessed via crystal violet assay and flow cytometry analysis. The effect of exposure time on microbial viability (Time-Kill) was evaluated. Finally, ultrastructural alterations were evaluated through scanning electron microscopy (SEM). Both arginine-substituted peptides [Arg]3M-PONTX-Dq3a[1-15] and [Arg]4M-PONTX-Dq3a[1-15], showed lowest MIC and MLC values (each 0.78 µM). In the biofilm formation assays, the peptide [Arg]3M-PONTX-Dq3a [1-15] showed MBIC of 3.12 µM against the two tested strains. Both peptides were able to alter the membrane permeability approximately by 80%. The treatment with MIC was able to eliminate bacteria after 2 h of contact on the other hand, treatment with half of the MIC, the population of both bacterial strains remained constant for up to 12 h, indicating a possible bacteriostatic effect. The SEM results showed that the treatment with the lowest concentration (0.78 µM) of both peptides caused disruption of the cell membrane, destabilization of the intercellular interaction and the CLM of [Arg]4M-PONTX-Dq3a [1-15] resulted in the complete eradication of the bacteria. Thus, this study describes two AMPs active against MSSA and MRSA and also inhibits the biofilm formation of these stains. This study finds [Arg]3M-PONTX-Dq3a[1-15] and [Arg]4M-PONTX-Dq3a[1-15] as alternative substances to treat resistant and/or biofilm-forming strains.

Dinoponera quadriceps venom as a source of active agents against Staphylococcus aureus.

Staphylococcus aureus is a highly virulent pathogen, capable of biofilm formation and responsible for thousands of deaths each year. The prevalence of Methicillin-Resistant S. aureus (MRSA) strains has increased in recent years and thus, the development of new antibiotics has become necessary. Antimicrobial Peptides (AMPs) are effective against a variety of multidrug-resistant bacteria and low levels of resistance have been reported regarding these molecules. Dinoponera quadriceps ant venom (DqV) has been described regarding its effect against S. aureus. In this study, we have evaluated the antibacterial effect of DqV-AMPs, the dinoponeratoxins (DNTxs), against Methicillin-Sensitive and a Methicillin-Resistant S. aureus strains. Our results show DNTx M-PONTX-Dq3a as a potent inhibitor of both strains, being able to prevent biofilm formation at low micromolar range (0.78-3.12 µM). It also showed a short-time effect through membrane disruption. M-PONTX-Dq3a opens up new perspectives for the prevention of biofilm formation through the development of anti-adhesive surface coatings on medical devices, as well as the treatment of resistant strains in skin or soft tissue infections.