LL-37 Peptide's Complex Role in Oral Health and Disease Unveiled

The LL-37 antimicrobial peptide is a crucial component of the body's innate immune system, known for its broad-spectrum antimicrobial activity and immunomodulatory functions. While essential for host defense, its precise and often dualistic role in maintaining oral health versus contributing to oral diseases like periodontitis and oral cancer is not fully understood. This narrative review aims to synthesize current knowledge on LL-37's molecular characteristics and its multifaceted involvement in various oral conditions.

The review confirmed that LL-37 exhibits potent antimicrobial activity against a wide array of oral pathogens, including bacteria and fungi, contributing significantly to the innate immune defense of the oral mucosa. It also plays a key role in immunomodulation and wound healing, promoting tissue repair. However, its dysregulation is implicated in pathology: in periodontitis, LL-37 levels are often elevated by 2-5 fold in gingival crevicular fluid, where it can contribute to both protection and inflammation-driven tissue destruction. Conversely, in oral squamous cell carcinoma, LL-37 can promote angiogenesis and metastasis, with studies showing up to a 3-fold increase in tumor growth in some models. The review's most critical finding is that LL-37's impact on oral health is highly context-dependent, acting as both a protective agent and a contributor to pathology depending on the specific disease state and local microenvironment.