Circulating biomarkers of nitrosative stress, protein glycoxidation and inflammation in maxillofacial surgery patients treated with titanium implants.

Background: Titanium (Ti) biomaterials are widely used in the surgical management of maxillofacial trauma, in oncology and orthognathic surgery. Although Ti is considered highly biocompatible, adverse reactions at the implant site have been reported in numerous clinical studies. However, the influence of Ti mandibular implants on glutathione metabolism, nitrosative stress and systemic inflammation has not been investigated to date.

Objectives: The study aimed to evaluate the acute (short-term) effects of Ti mandibular implants on the circulating biomarkers of the antioxidant defense system, on oxidative and nitrosative stress, as well as the inflammatory response of the blood plasma/erythrocytes, in maxillofacial surgery patients compared to the control group.

Material and methods: The experimental group consisted of 40 patients with bilateral mandibular fractures, who received osteosynthesis treatment with the use of Ti-6Al-4V alloy miniplates and screws. The control group comprised 40 ageand gender-matched patients who were qualified for the surgical treatment of craniofacial defects through bimaxillary osteotomy.

Results: An increase in the activity of pro-oxidant enzymes (↑ nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX), ↑ xanthine oxidase (XO)), impaired glutathione metabolism (↓ total glutathione, ↑ oxidized glutathione (GSSG), ↓ reduced glutathione (GSH), ↓ redox status), higher levels of oxidative stress (↓ total thiols, ↑ malondialdehyde (MDA), ↑ lipid hydroperoxides (LOOHs)), ↓ total antioxidant status (TAS)), carbonyl stress (↑ dityrosine, ↑ N-formylkynurenine) and nitrosative stress (↑ nitric oxide (NO), ↑ S-nitrosothiols, ↑ peroxynitrite, ↑ nitrotyrosine), as well as an intensified systemic inflammatory response (↑ interleukin (IL)-1β, ↑ IL-6), were observed in maxillofacial surgery patients.

Conclusions: Despite the fact that the study examined only the circulating biomarkers of redox balance and inflammation, the results suggest that a systemic inflammatory response can be triggered by local immune reactions. Systemic inflammation and oxidative stress may stem from an early adaptive immune response to foreign objects in the body. Although further research is required, the removal of the existing Ti mandibular implants should be considered.