Sessions

Nowadays the spreading of antimicrobial resistance (AMR) is one of the most significant global health issues, induced by the excessive or irresponsible use of antibiotics. The pork industry plays a particularly important role in the spreading of AMR, as large animal populations and production maximization significantly increase the usage of antibiotic treatments. The decreasing efficacy of antimicrobial agents poses challenges not only to veterinary medicine but also to public health and food safety, highlighting the need for alternatives to conventional antibiotic therapy. A good example of this is the study of the effects of antimicrobial peptides (AMPs), which are important components of innate immunity and may offer promising opportunities in the defence against pathogens.

The aim of this study was to characterize the anti-inflammatory and immunomodulatory properties of AMPs and to understand their role in the pathogenesis of infections. In our experiment, we investigated the immunomodulatory effects of PR-39, an AMP isolated from the small intestine of pig, with particular focus on its role in oxidative processes. Our studies were performed on a porcine primary hepatic coculture, as the liver plays a key role in regulation of systemic inflammatory responses. In our in vitro experiment, porcine hepatocytes and non-parenchymal cells were cocultured and treated with PR-39 under physiological and lipopolysaccharide (LPS)-induced inflammatory conditions: PR-39 (1, 5, and 10 µmol/L), LPS (30 µg/mL), or a combination of both. The metabolic activity of the cells was measured using Cell Counting Kit-8, and the concentration of extracellular (EC) hydrogen peroxide was determined by monitoring the state of redox homeostasis of the cells. The scale of lipid peroxidation was assessed by measuring EC malondialdehyde (MDA) concentrations using a porcine-specific sandwich ELISA kit. The inflammatory response was characterized by measuring the levels of interleukin (IL)-1ß, IL-6, IL-12, interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) using Luminex xMAP technology.

LPS alone induced a cytokine response, without measurable changes in the values of redox parameters. PR-39 reduced the release of IL-1ß and IL-12, and also moderated the LPS-induced IL-1ß and IFN-γ peak, thus reducing the inflammatory response, further it decreased the release of EC hydrogen peroxide, while at the same time increasing lipid peroxidation at higher concentrations. The results of our experiment support the potential applicability of PR-39 in pig health based on its immunomodulatory properties and also indicates that PR-39 may be an ideal subject for research aimed at getting a hold on AMR. Our in vitro experiment must be followed by numerous in vivo studies to select the most effectively applicable AMP, as well as the optimal treatment time and concentration.