Int Endod J. 2015 Jul 22. doi: 10.1111/iej.12511. [Epub ahead of print]

The dental pulp stem cell niche based on aldehyde dehydrogenase 1 expression.

Machado CV¹, Passos ST¹, Campos TM¹, Bernardi L¹, Vilas-Bôas DS¹, Nör JE¹, 

Abstract

AIM:

To detect cells expressing the stem cell marker ALDH1 (aldehyde dehydrogenase1) in the pulp of human permanent teeth and to investigate the expression of ALDH1 in isolated dental pulp cells.

METHODOLOGY:

Pulp tissue was collected and processed for immunohistochemistry to detect ALDH1, STRO-1 and CD90 positive cells. In addition, cells were isolated and analyzed by flow cytometry for ALDH1 activity, and for the cell surface markers CD44, CD73, CD90, STRO-1 and CD45. Cells were also examined for multi-differentiation capacity. Within these cells, an ALDH1⁺ cell subpopulation was selected and evaluated for multi-differentiation capacity.

RESULTS:

The immunohistochemistry analyses showed that ALDH1, CD90 and STRO-1 positive cells were located mainly in the perivascular areas and nerve fibres of dental pulps. Cells on the fifth passage had high expression for CD44, CD73 and CD90, whereas moderate labeling was observed for STRO-1 and ALDH1 in flow cytometry analysis. On the same passages, cells were able to differentiate into osteogenic, adipogenic and chondrogenic lineages. The ALDH1⁺ cell subpopulation also demonstrated multi-lineage differentiation ability.

CONCLUSIONS:

Dental pulp stem cells reside in the vicinity of blood vessels and nerve fibres, indicating the possible existence of more than one stem cell niche in dental pulps. Furthermore, ALDH1 was expressed by isolated dental pulp cells, which had mesenchymal stem cell characteristics. Thus, it can be suggested that ALDH1 may be used as a DPSC marker.