Uptake and intracytoplasmic storage of pigmented particles by human CD34+ stromal cells/telocytes: endocytic property of telocytes.
Bottom Line: Our results demonstrate that CD34+ TCs have endocytic properties (phagocytic-like TCs: phTCs), with the capacity to uptake and store India ink particles. phTCs conserve the characteristics of TCs (long, thin, bipolar or multipolar, moniliform cytoplasmic processes/telopodes, with linear distribution of the pigment) and maintain their typical distribution.Our ultrastructural observation of melanin-storing stromal cells with characteristics of TCs (telopodes with dichotomous branching pattern) favours this possibility.In conclusion, intestinal TCs have a phagocytic-like property, a function that may be generalized to TCs in other locations.
Affiliation: Department of Anatomy, Pathology, Histology and Radiology, Faculty of Medicine, University of La Laguna, Tenerife, Spain.Show MeSH
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Mentions: Stromal cells and macrophages with intracytoplasmic-pigmented particles were seen in the specimens of the colonic segments tattooed in vivo with India ink (Fig. 1). Some extracellular particles of pigment were also present in the interstitium. The stromal cells with pigmented particles expressed CD34 (CD34+ phTCs) and where the pigment was released practically all the CD34+ TCs showed pigment. CD34+ phTCs displayed a small oval or triangular body and long, thin bipolar or multipolar cytoplasmic processes (telopodes; Fig. 1). The intracellular pigment was present in the somatic region around the nucleus and in the telopodes. phTCs were also stained with anti-vimentin and did not express CD45, CD68, CD31 (Fig. 2A), αSMA (Fig. 2B), or h-caldesmon. In tissue sections stained with haematoxylin and eosin, the intracellular pigment showed a peculiar linear distribution (Figs 1A, B and 2C), drawing the processes of some stromal cells whose morphology and arrangement coincided with that of the anti-CD34 stained phTCs. (In Figs 1 and 2, compare stromal cells obtained from tissue sections stained with haematoxylin and eosin and with anti-CD34/CD34+ phTCs.)
Affiliation: Department of Anatomy, Pathology, Histology and Radiology, Faculty of Medicine, University of La Laguna, Tenerife, Spain.