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Introduction: Chronic wounds are an increasing problem for health care all over the world. New treatment options for this illness are desired, especially antimicrobial agents. Silver nanoparticles (AgNPs) can be a potential substance that may be used in treatment of chronic wounds due to the growing antibiotic resistance. Aim: To synthetize silver nanoparticles that are stable, pure and effective against bacteria. Material and methods: The synthesis was conducted with chemical methods using different coating factors. The antistaphylococcal properties were analysed with the microdilution method to determine minimal inhibition concentrations (MIC) value. AgNPs were purified by dialysis. Moreover, keratinocyte cytotoxic properties of AgNPs were also assessed. Results: A method of synthesizing stable and efficient AgNPs has been developed. The type of the coating substance has a significant effect on AgNPs antimicrobial properties. Most of the silver nanoparticles, synthesized based on literature data, turned out to be durable during a few hours. This study has proven that depending on the coating factor, AgNPs stability ranges from 4 weeks to even 12 months. Unfortunately, the type of the stabilizer used also affects the cytotoxicity of AgNPs. It has been shown that dialysis is a substance purification method that is cheap, simple and easy to apply when dealing with high volume solutions. Conclusions: AgNPs could be an alternative to widely used antibiotics and disinfectants. Nevertheless, the introduction of those substances to health care requires detailed long-term research not only in the field of safe use, yet also durability and purity of AgNPs solutions used. [ABSTRACT FROM AUTHOR]

During recent decades, the market for peptide-based drugs, including antimicrobial peptides, has vastly extended and evolved. These drugs can be useful in treatment of various types of disorders, e.g., cancer, autoimmune diseases, infections, and non-healing wounds. Although peptides are less immunogenic than other biologic therapeutics, they can still induce immune responses and cause allergies. It is important to evaluate the immunogenic and allergic potential of peptides before they are forwarded to the expensive stages of clinical trials. The process of the evaluation of immunogenicity and cytotoxicity is complicated, as in vitro models and bioinformatics tools cannot fully simulate situations in the clinic. Nevertheless, several potentially promising tests for the preclinical evaluation of peptide drugs have been implemented (e.g., cytotoxicity assays, the basophil activation test, and lymphocyte activation assays). In this review, we focus on strategies for evaluation of the allergic potential of peptide-based therapeutics. [ABSTRACT FROM AUTHOR]

A peptidomimetic called A20 (Cystapep 1) structurally based upon the N -terminal fragment of human cystatin C is known to have strong antibacterial properties. A20 is characterized by high activity against several bacterial strains often isolated from infected wounds, including methicillin-resistant S. aureus (MRSA). In this work we wanted to explore the therapeutic potential of A20 in the treatment of wound infections. We examined, cytotoxicity, allergenicity and impact of A20 on the proliferation and viability of human keratinocytes. Furthermore, the previously described antimicrobial action of A20 has been confirmed here with reference strains of bacteria and extended by several other species. The A20 was highly active against Gram-positive bacteria with minimal inhibitory (MIC) and minimal bactericidal concentrations (MBC) between 8 and 128 μg/mL. A20 did not affect proliferation of primary human keratinocytes in concentrations up to 50 μg/mL. At the same time, it did not activate Peripheral Blood Mononuclear Cells (PBMCs), including basophils or neutrophils in vitro . Interestingly A20 was found to display immunomodulatory functions as it influences the production of Th2 cytokines (IL-4 and IL-13) by activated PBMCs. It was also resistant to degradation for at least 48 h in human plasma. The results indicate that A20 is effective against the multiantibiotic-resistant bacteria and has a high safety profile, which makes it a promising antimicrobial drug candidate. [ABSTRACT FROM AUTHOR]

Abstract: A series of linear and cyclic fragments and analogs of two peptides (OGTI and HV-BBI) isolated from skin secretions of frogs were synthesized by the solid-phase method. Their inhibitory activity against several serine proteinases: bovine β-trypsin, bovine α-chymotypsin, human leukocyte elastase and cathepsin G from human neutrophils, was investigated together with evaluation of their antimicrobial activities against Gram-negative bacteria (Escherichia coli) and Gram-positive species isolated from patients (Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus sp., Streptococcus sp.). The cytotoxicity of the selected peptides toward an immortal human skin fibroblast cell line was also determined. Three peptides: HV-BBI, its truncated fragment HV-BBI(3–18) and its analog [Phe8]HV-BBI can be considered as bifunctional compounds with inhibitory as well as antibacterial properties. OGTI, although it did not display trypsin inhibitory activity as previously reported in the literature, exerted antimicrobial activity toward S. epidermidis. In addition, under our experimental conditions, this peptide did not show cytotoxicity. [Copyright &y& Elsevier]