HISTOLOGY AND HISTOPATHOLOGY

Cellular and Molecular Biology

 

Human resident CD34+ stromal αSMA+ cells during repair

L. Díaz-Flores1, R. Gutiérrez1, M.P. García2, M. González1, F.J. Sáez3, F. Aparicio1, L. Díaz-Flores Jr1 and J.F. Madrid4

1Department of Anatomy, Pathology, Histology and Radiology, Faculty of Medicine, University of La Laguna, Tenerife, 2Department of Pathology, Hospiten® Hospitals, Tenerife, 3Department of Cell Biology and Histology, UFI11/44, School of Medicine and Dentistry, University of the Basque Country, UPV/EHU, Leioa and 4Department of Cell Biology and Histology, School of Medicine, Regional Campus of International Excellence, "Campus Mare Nostrum" University of Murcia, Murcia, Spain

Offprint requests to: L. Diaz Flores, Departamento de Patología, Facultad de Medicina, Universidad de La Laguna, Tenerife, Spain. e-mail: rgutier@ull.es


Summary. We studied the progenitor capacity of human resident CD34+ stromal cells/telocytes (SC/TCs) in the enteric wall affected by inflammatory/repair processes (appendicitis, diverticulitis of large bowel and Crohn's disease of the terminal ileum) at different stages of evolution (inflammatory, proliferative and remodelling). In these conditions, CD34+ SC/TCs are activated, showing changes, which include the following overlapping events: 1) separation from adjacent structures (e.g., from vascular walls) and location in oedematous spaces, 2) morphological modifications (in cell shape and size) with presence of transitional cell forms between quiescent and activated CD34+ SC/TCs, 3) rapid proliferation and 4) loss of CD34 expression and gain of αSMA expression. These events mainly occur in the inflammatory and proliferative stages. During the loss of CD34 expression, the following findings are observed: a) irregular cell labelling intensity for anti-CD34, b) co-localization of CD34 and actin, c) concurrent irregular labelling intensity for αSMA and d) αSMA expression in all stromal cells, with total loss of CD34 expression. While CD34 expression was conserved, a high proliferative capacity (Ki-67 expression) was observed and vice versa. In the segments of the ileum affected by Crohn's disease, the stromal cells around fissures were αSMA+ and, in the transitional zones with normal enteric wall, activated CD34+ SC/TCs were observed. In conclusion, human resident CD34+ SC/TCs in the enteric wall have progenitor capacity and are activated with or without differentiation into αSMA+ stromal cells during inflammatory/repair processes. Histol Histopathol 30, 615-627 (2015)

Key words: CD34+ stromal cells, Telocytes, αSMA+ stromal cells, Bowel, Crohn's disease

DOI: 10.14670/HH-30.615