A multi-platform analysis of human gingival crevicular fluid reveals ferroptosis as a relevant regulated cell death mechanism during the clinical progression of periodontitis

Focusing on ferroptosis in alveolar bone loss during periodontitis: From mechanisms to therapies

Periodontitis is an oral immunoinflammatory disease induced by bacterial infection. During periodontitis, the aggravating destruction of the alveolar bone can result in tooth movement and even tooth loss. Current conventional treatments for periodontitis primarily focus on infection control, but their effectiveness in halting and restoring alveolar bone destruction is limited. To identify additional therapeutic targets, researchers have been dedicated to investigating other pathological mechanisms underlying alveolar bone loss during periodontitis. Recently, findings indicate that ferroptosis plays a role in the development of periodontitis. Ferroptosis is a nonapoptotic type of cell death marked by iron accumulation and lipid peroxidation. Recent investigations have revealed the complex interplay of ferroptosis and inflammation. The positive feedback loop between ferroptosis and inflammation may significantly contribute to the exacerbation of alveolar bone loss. In light of the advancements in research within this field in recent years, this review intends to thoroughly summarize the processes by which ferroptosis aggravates alveolar bone loss during periodontitis, along with relevant ferroptosis-targeted therapeutic agents. By highlighting the latest advancements in this area, we hope this review will inspire researchers to develop novel therapeutic strategies for more effective inflammation control and regeneration of alveolar bone.

Multivariate Spectroscopic Analysis of Protein Secondary Structures in Gingival Crevicular Fluid: Insights from FTIR Amide III Band Across Oral Disease Stages

This study applies multivariate data analysis to deconvolute the spectral profiles of the Amide III region in the infrared spectra of gingival crevicular fluid (GCF). This reveals the impact of major oral diseases, such as dental caries and periodontal diseases, on the transformation of the secondary structure of GCF proteins. A two-stage analytical approach was employed: first, principal component analysis (PCA) was performed to establish the main factors of variation in the data, followed by pairwise comparisons of the samples based on the results of the Amide III profile deconvolution. The analysis also accounted for comorbidities, such as oncological and gastrointestinal diseases. This approach allowed for the identification of subtle differences in the composition and conformation of the secondary structure of GCF proteins while accounting for the superposition of multiple influencing factors. This methodology was effective in identifying biomarkers of oral diseases in GCF. For the first time, it has been demonstrated that the relative content of the β-sheet-associated component in the spectral profile of the secondary structure element of the protein fraction of GCF serves as a statistically significant marker for dental caries, regardless of the presence or absence of other diseases. Additionally, a significant decrease in the relative content of α-helix structures was observed in GCF from patients with oncological diseases. The changes in the spectral profile of the Amide III band of GCF identified in this study have not been previously detected using molecular spectroscopy, correlated with the secondary structure of proteins, or analyzed using multivariate analysis methods.

Engineered Probiotics with Low Oxygen Targeting Porphyromonas gingivalis and Gingival Fibroblasts for the Treatment of Periodontitis

The overuse of antibiotics has increased the prevalence of drug-resistant bacteria in periodontitis. "Sentinel" gingival fibroblasts, stimulated by pathogenic bacteria, continue to release signaling factors that affect stem cell repair and recruit immune cells, resulting in persistent inflammation in periodontal tissues, eventually leading to the loosening and loss of teeth. Periodontal pathogenic bacteria cause surface hypoxia, and gingival fibroblasts in the inflammatory microenvironment express HIF-1α, promoting hypoxic areas in periodontal pockets. No drug delivery system is available for the hypoxic region of periodontal pockets. We synthesized BI NPs via berberine (BBR) and indocyanine green (ICG) and formed BIP NPs by wrapping BI NPs with polydopamine (PDA), and the BIP NPs were delivered to the hypoxic region of the periodontal pocket by hitchhiking with the anaerobic probiotic Bifidobacterium bifidum (Bif). The BIP NPs released berberin (BBR) under near-infrared (NIR) irradiation, which inhibited the sulfur metabolism of Porphyromonas gingivalis via mild photothermal action and BBR-targeted serine acetyltransferase, resulting in a decrease in resistance to oxidative stress, thus exerting a nonantibiotic bacteriostatic effect. This mild photothermal effect facilitated the uptake of BIP NPs bygingival fibroblasts. Moreover, BBR targeted nuclear factor-erythroid 2-related factor 2 (NRF2) to reduce ferroptosis, and the gingival fibroblast supernatant modulated macrophage polarization through the NF-κB pathway. In the periodontitis rat model, Bif@BIP+NIR treatment carried the drug to deep periodontal pockets, decreasing local gingival ferroptosis and alleviating periodontitis symptoms. To summarize, engineered probiotics target low-oxygen periodontal pockets for drug delivery, P. gingivalis for nonantibiotic bacterial inhibition, and gingival fibroblasts to mitigate ferroptosis, thus alleviating periodontitis to reduce periodontitis.

Ferroptosis and cuproptosis in periodontitis: recent biological insights and therapeutic advances

Periodontitis is a significant global public health issue associated with the onset and progression of various systemic diseases, thereby requiring additional research and clinical attention. Although ferroptosis and cuproptosis have emerged as significant areas of research in the medical field, their precise roles in the pathogenesis of periodontitis remain unclear. We aim to systematically summarize the current research on ferroptosis and cuproptosis in periodontal disease and investigate the roles of glutathione pathway and autophagy pathway in connecting ferroptosis and cuproptosis during periodontitis. Further, we propose that a homeostatic imbalance of copper and iron, driven by periodontal pathogens, may contribute to elevated periodontal oxidative stress, representing a potential unifying link between ferroptosis and cuproptosis involved in periodontitis. This article presents a comprehensive overview of the molecular mechanisms underlying ferroptosis and cuproptosis in periodontitis, offering novel theoretical insights into its pathogenesis and potential therapeutic targets.