Antimicrobial peptides: therapeutic potentials.

The increasing appearance of multidrug-resistant pathogens has created an urgent need for suitable alternatives to current antibiotics. Antimicrobial peptides (AMPs), which act as defensive weapons against microbes, have received great attention because of broad-spectrum activities, unique action mechanisms and rare antibiotic-resistant variants. Despite desirable characteristics, they have shown limitations in pharmaceutical development due to toxicity, stability and manufacturing costs. Because of these drawbacks, only a few AMPs have been tested in Phase III clinical trials and no AMPs have been approved by the US FDA yet. However, these obstacles could be overcome by well-known methods such as changing physicochemical characteristics and introducing nonnatural amino acids, acetylation or amidation, as well as modern techniques like molecular targeted AMPs, liposomal formulations and drug delivery systems. Thus, the current challenge in this field is to develop therapeutic AMPs at a reasonable cost as well as to overcome the limitations.

Antimicrobial and host defense peptides for therapeutic use against multidrug-resistant pathogens: new hope on the horizon.

The concept of using antimicrobial peptides (AMPs) and host defense peptides (HDPs) as therapeutics was first introduced in the late 1990s. However, an AMP drug has yet to reach the market. AMPs and HDPs have intriguing potential as therapeutics: the peptides are evolutionary conserved, and are critical components of the innate immune system of all eukaryotes; their evolution pre-dates the appearance of the adaptive immune system; and they do not readily engender bacterial resistance. Nevertheless, there are significant obstacles to the use of AMPs and HDPs in humans, including the need to conduct clinical trials to demonstrate efficacy, and the capacity to manufacture AMPs and HDPs in a cost-effective manner. Progress in both of these areas would support the exciting possibility that AMPs and HDPs could be developed as therapeutics that kill pathogens and facilitate the immune response.