The role of Neutrophils in oral Biofilm formation

Almaarik, Basmah ORCID: 0000-0001-6362-8434 (2025). The role of Neutrophils in oral Biofilm formation. University of Birmingham. Ph.D.

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Abstract

Biofilms are complex multicellular communities embedded in an extracellular polymeric substance (EPS). EPS contains extracellular DNA (eDNA), which contributes to its stability and complexity. There are many types of in vivo biofilms; the periodontal biofilm is one example. Bacterial biofilms are a leading cause of periodontitis, but host inflammatory responses against these are essential factors contributing to periodontal disease occurrence and severity. The primary protective leukocyte type against oral pathogens is neutrophil. This innate immune cell constantly surveils the periodontal tissues and migrates into the gingival crevice. Neutrophils express a variety of antimicrobial mechanisms in response to proinflammatory signals, including degranulation, phagocytosis, and the production of weblike extracellular DNA referred to as neutrophil extracellular traps (NETs). NET production is closely related to reactive oxygen species (ROS) production. An imbalance in neutrophil antimicrobial responses in the oral cavity is thought to contribute to periodontitis. This thesis describes the interactions of neutrophils with representative bacteria of early colonisers of periodontal biofilms, namely the streptococci S. oralis, S. mitis, and S. intermedius in single and mixed species scenarios. It also assesses several in vitro models for biofilm formation and evaluates neutrophil retention in these. Furthermore, the dynamics of neutrophils and the periodontal pathogenic strain A. actinomycetemcomitans were analysed and compared to the streptococcal species. The evaluated biofilm growing methods included two dynamic models (flow cell and flow chamber) and one static model (multiwell plate) for biofilm development...

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):