Respiratory infections are a major clinical problem, and treatment is increasingly complicated by the emergence of microbial antibiotic resistance. Development of new
antibiotics is notoriously costly and slow; therefore, alternative strategies are needed.
Antimicrobial peptides, central effector molecules of the immune system, are being considered as alternatives to conventional
antibiotics. These
peptides display a range of activities, including not only direct antimicrobial activity, but also
immunomodulation and
wound repair. In the lung, airway epithelial cells and neutrophils in particular contribute to their synthesis. The relevance of
antimicrobial peptides for host defense against
infection has been demonstrated in animal models and is supported by observations in patient studies, showing altered expression and/or unfavorable circumstances for their action in a variety of
lung diseases. Importantly,
antimicrobial peptides are active against microorganisms that are resistant against conventional
antibiotics, including multidrug-resistant bacteria. Several strategies have been proposed to use these
peptides in the treatment of
infections, including direct administration of
antimicrobial peptides, enhancement of their local production, and creation of more favorable circumstances for their action. In this review, recent developments in
antimicrobial peptides research in the lung and clinical applications for novel
therapies of
lung diseases are discussed.