Salivary NLRP3 inflammasome as a promising biomarker for palatal mucosa healing in diabetes mellitus: A pilot study.

BACKGROUND

The NOD-like receptor family pyrin domain-containing protein 3 (NLRP3) inflammasome is a protein complex that regulates IL-1β activation. Despite its known role in dermal healing, its involvement in oral mucosal healing remains poorly understood.

METHODS

Twenty-four subjects, including 12 with Type 2 diabetes mellitus (T2DM) and 12 normoglycemic controls (C), underwent a surgical procedure for mucogingival defect treatment in which a graft was harvested from the palate. The palatal wound was assessed for remaining wound area (RWA) and epithelialization (EPT) until 3 months. Wound exudate was collected on days 3 and 7 post-operatively to analyze inflammatory biomarkers, proteinases, and growth factors. NLRP3, PYCARD, CASPASE-1, and interleukin-1beta (IL-1β) salivary levels were assessed preoperatively and 7 days post-surgery.

RESULTS

Lower EPT rates and greater RWA were observed in T2DM compared to Control on days 7 and 14 postoperatively. Higher MMP-9 concentration was detected in T2DM subjects on days 3 and 7 post-surgery (p < 0.05). Salivary NLRP3 and PYCARD increased in the C group at 7 days post-surgery (p ≤ 0.04), whereas IL-1β was higher over time in the T2DM group (p = 0.003). At baseline, NLRP3 and PYCARD levels were higher in T2DM (p ≤ 0.005), whereas PYCARD (p = 0.01) and CASPASE-1 (p = 0.05) remained elevated at 7 days compared with C. A positive association between salivary NLRP3 levels with IL-1β (r = 0.46) and tumor necrosis factor-alpha (TNF-α) (r = 0.47) from wound exudate on day 7 was observed. PYCARD levels associated with IL-1β (r = 0.48) and TNF-α (r = 0.50) at the same time point. Principal component analysis of inflammasome-related markers and wound biomarkers on day 7 suggested a potential impact on delayed wound closure by day 14.

CONCLUSION

The NLRP3 inflammasome may be a promising biomarker for T2DM-related acute palatal healing due to its early upregulation and association with proinflammatory markers, with a potential impact on delayed wound closure.