Selective Phospholipase A2 Gene Expression in Peri-Implantitis: An Intra-Individual Paired Gingival Tissue Study

Phospholipase A2 (PLA2) enzymes participate in lipid metabolism and inflammatory signaling, but the expression of individual PLA2-family genes in peri-implantitis remains poorly characterized. This exploratory study compared the expression of PLA2G7, PLA2G4A, PLA2G6, and PLA2G12A in paired gingival samples from 19 patients with advanced peri-implantitis requiring implant removal. Inflamed tissue and clinically non-inflamed local reference tissue were collected adjacent to the same affected implant. Gene expression was assessed by quantitative reverse transcription polymerase chain reaction and normalized to on glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Paired expression differences were evaluated using Wilcoxon signed-rank tests with Benjamini-Hochberg adjustment. Complete paired data were available for 19 patients for three genes and 18 patients for PLA2G4A. PLA2G7 expression was higher in inflamed tissue in 15 of 19 patients, with a median fold change of 5.86 (interquartile range, 1.29-17.36; adjusted p = 0.0247). No significant paired differences were detected for the other three genes. In comparisons across genes, the fold change for PLA2G7 exceeded that for PLA2G12A after Holm adjustment, but did not differ significantly from those for PLA2G4A or PLA2G6. These findings suggest an association between advanced peri-implantitis and increased tissue-level PLA2G7 expression. Further studies are needed to establish its functional significance and confirm these preliminary findings.