ABSTRACT Aim To analyse gene expression profiles in human tissue samples obtained from dental implant sites with or without peri‐implantitis. Materials and Methods Soft‐tissue biopsy samples obtained from patients presenting with implants with severe peri‐implantitis and adjacent reference implants with no signs of peri‐implantitis were analysed by spatial transcriptomics ( n = 4), RNA‐sequencing ( n = 20) and immunohistochemistry ( n = 38). Results The analysis disclosed evident associations between distinct gene clusters and specific tissue compartments in both groups of specimens. Samples from peri‐implantitis sites showed higher levels of gene activity than samples from reference implant sites. Gene‐set enrichment analysis revealed that several important biological pathways, for example, ‘regulation of antimicrobial host response’, ‘collagen fibril organisation’ and ‘regulation of angiogenesis’, were severely dysregulated in peri‐implantitis lesions when compared to reference implant sites. Similarly, immunohistochemical evaluation showed elevated levels of proteins corresponding to the most up‐regulated, differentially expressed genes (DEGs), which were identified by spatial transcriptomics and RNA‐sequencing. Conclusions Peri‐implant lesions demonstrated associations between gene clusters and specific tissue compartments. Several biological pathways linked to the activation of host response towards bacterial insults were dysregulated in peri‐implantitis specimens when compared to reference implant samples.
Dionigi et al. (Sun,) studied this question.