A lab study showed that a synthetic version of the natural peptide LL‑37, called P60.4‑Ac, can block the harmful inflammation caused by bacterial components (LPS and LTA) in airway cells, reducing swelling that’s linked to ear and sinus infections.

Changes in the respiratory epithelium and chronic and recurrent infections are thought to play a central role in the pathogenesis of otitis media and sinusitis. The airway epithelium is the primary defense system of the respiratory tract. Bacterial cell membrane components like lipopolysaccharide (LPS) and lipoteichoic acid (LTA) can affect the mucociliary clearance function of the respiratory epithelium. P60.4-Ac is a synthetic antimicrobial peptide based on the structure of the cathelicidin LL-37 that neutralizes the pro-inflammatory activity of LPS and LTA. Normal respiratory sinus epithelium was cultured at the air liquid interface. The cells were incubated with LPS or LTA in the presence or absence of P60.4-Ac. P60.4-Ac neutralized the LPS- and LTA- induced effect on air-liquid interface cultured epithelial cells. P60.4-Ac significantly inhibited the increase in the epithelial layer caused by LPS or LTA. These data demonstrate that P60.4-Ac might be of clinical benefit in the management of otitis media with effusion and sinusitis.