ALDH1 expression and potential clinical implications in chronic inflammatory periapical lesions

Abstract

Aldehyde dehydrogenase 1 (ALDH-1) is a marker of stem cells in a variety of diseases, but its role in individuals with chronic inflammatory periapical lesions remains unknown. The aim of this study was to investigate the presence of cells with a stem cell profile based on the immunoexpression of ALDH-1 in periapical granulomas (PGs) and radicular cysts (RCs). A total of 51 cases of periapical lesions (25 PGs and 26 RCs) were subjected to immunohistochemical study. The anti-ALDH-1 antibody was applied using the immunoperoxidase technique. An immunoexpression score (intensity vs. percentage of cells) was used, with the cases being classified as low expression (score: 0 to 4) and high expression (score: 6 to 9). The Chi-square test was used with a 5% level of significance. Immunoexpression of ALDH-1 was detected in all cases of PGs and RCs. In PG cases, the expression was diffuse in connective tissue cells, with most cases exhibiting high expression (n = 18; 69.2%), while in RC cases the expression revealed focal distribution in cells of the capsule and epithelial cells of the cystic lining, with most cases classified as low expression (n = 18; 72%). Significant differences in the expression scores of ALDH-1 were observed in PGs (p = 0.003). The variable expression of ALDH-1 suggests the presence of cells with stem cell profiles in PGs and RCs. These findings suggest that periapical tissues infiltrated by chronic inflammation can recruit important cells for the repair or evolution of periapical lesions.

Mechanisms of bone remodeling and therapeutic strategies in chronic apical periodontitis

“…In the natural pathology of CAP, the tissue at the site of inflammation has the ability to recruit stem cells (Farias et al, 2022), but endogenous stem cells alone are not sufficient to support tissue repair. Mesenchymal stem cells (MSCs) are widely used in tissue engineering (Xing et al, 2019).…”

ALDH1 immunoexpression in epithelial and stromal cells of oral lichen planus and lesions with lichenoid inflammatory infiltrate

“…The presence of these phenotypes to ALDH1+ cells were registered in other studies ( 14 , 22 ), which have been associated with a better prognosis or simply considered as stem cells ( 23 ). In the present study, we presume that the positive stromal cells are antigen-presenting cells (APCs), including dendritic cells.…”

The Stem Cell Expression Profile of Odontogenic Tumors and Cysts: A Systematic Review and Meta-Analysis

“…The vast majority of studies (24 out of 29) reported experiments on FFPE tissue samples ( Table S3 ), two studies included both fresh-frozen and FFPE samples [ 6 , 39 ], one study reviewed only fresh-frozen samples [ 42 ], and in vitro analysis of human odontogenic lesion-derived cells was performed in two studies [ 43 , 47 ]. A minority of studies (10 out of 29) documented the microscopic diagnosis of included odontogenic entities, either by providing a detailed microscopic description [ 6 , 11 , 12 , 29 , 35 ] or by mentioning an appropriate reference [ 13 , 32 , 36 , 37 , 39 ], e.g., the WHO 2017 [ 1 ] or 2005 [ 51 ] editions for odontogenic tumors and cysts.…”

“…One of the studies used a monoclonal antibody against the CD44H standard form and a polyclonal antibody against the CD44V3 isoform, with the same results [ 50 ]. Immunohistochemical experiments on FFPE tissue samples also revealed staining of c-Myc in the epithelium of RC [ 45 ], of CD73 and CD105 in the cystic capsule [ 11 ], and of ALDH1 in both epithelial and mesenchymal cells of RC [ 35 ]. Moreover, flow cytometric analysis confirmed CD44, CD73, and CD105 expression in mesenchymal cells isolated from human RCs (HRCMCs), and also showed CD13, CD29, and CD90 expression in those cells at similar levels with dental pulp stem cells (DPSCs), except for CD105, which was underexpressed in HRCMCs compared to DPSCs [ 43 ].…”

“…Thus, as confirmed by our meta-analysis ( Figure S1 ), the expression of this marker does not seem to differ significantly between AMBL and DF. Similarly, no significant differences were noted in stem cell markers’ expression between RC and PG groups [ 11 , 50 ], except for a single study that found significantly lower ALDH1 expression in RC than PG [ 35 ].…”