C-kit immunopositive interstitial cells (Cajal-type) in human myometrium.
Previous reports describing Cajal-like interstitial cells in human uterus are contradictory in terms of c-kit immunoreactivity: either negative (but vimentin-positive) in pregnant myometrium, or positive, presumably in the endometrium. The aim of this study was to verify the existence of human myometrial Cajal-like interstitial cells (m-CLIC). Six different, complementary approaches were used: 1) methylene-blue supravital staining of tissue samples (cryosections), 2) methylene blue and Janus green B vital staining (m-CLIC and mitochondrial markers, respectively), and 3) extracellular single-unit electrophysiological recordings in cell cultures, 4) non-conventional light microscopy on glutaraldehyde/osmium fixed, Epon-embedded semi-thin sections (less than 1 microm) stained with toluidine blue (TSM), 5) transmission electron microscopy (TEM), and 6) immunofluorescence (IF). We found m-CLIC in myometrial cryosections and in cell cultures. In vitro, m-CLIC represented approximately 7% of the total cell number. m-CLIC had 2-3 characteristic processes which were very long (approximately 60 microm), very thin (< or =0.5 microm) and moniliform. The dilated portions of processes usually accommodated mitochondria. In vitro, m-CLIC exhibited spontaneous electrical activity (62.4+/-7.22 mV membrane potentials, short duration: 1.197+/-0.04 ms). Moreover, m-CLIC fulfilled the usual TEM criteria, the so-called 'gold' or 'platinum' standards (e.g. the presence of discontinuous basal lamina, caveolae, endoplasmic reticulum, and close contacts between each other, with myocytes, nerve fibers and/or capillaries etc.). IF showed that m-CLIC express CD117/c-kit, sometimes associated with CD34, with vimentin along their processes. In conclusion, we describe myometrial Cajal-like interstitial cells that have affinity for methylene blue and Janus green B vital dyes, fulfill (all) TEM criteria, express CD117/c-kit and have spontaneous electric activity.
Ciontea
Sanda M
SM
Department of Cellular and Molecular Medicine, Carol Davila University of Medicine and Pharmacy, Bucharest, 050474, Romania. sciontea@univermed-cdgm.ro
Radu
E
E
Regalia
T
T
Ceafalan
Laura
L
Cretoiu
D
D
Gherghiceanu
Mihaela
M
Braga
R I
RI
Malincenco
Mariana
M
Zagrean
L
L
Hinescu
M E
ME
Popescu
L M
LM
D000199:Actins / Q000032:analysis; D018952:Antigens, CD34 / Q000032:analysis; D002478:Cells, Cultured; D003239:Connective Tissue Cells / Q000737:chemistry / Q000166:cytology* / Q000648:ultrastructure; D004594:Electrophysiology; D005260:Female; D005455:Fluorescent Antibody Technique; D017629:Gap Junctions / Q000648:ultrastructure; D006801:Humans; D008751:Methylene Blue / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D032389:Myocytes, Smooth Muscle / Q000737:chemistry / Q000166:cytology / Q000648:ultrastructure; D009215:Myometrium / Q000737:chemistry / Q000166:cytology* / Q000648:ultrastructure; D011247:Pregnancy; D019009:Proto-Oncogene Proteins c-kit / Q000032:analysis*; D014746:Vimentin / Q000032:analysis
D000199:Actins; D018952:Antigens, CD34; D014746:Vimentin; D019009:Proto-Oncogene Proteins c-kit; D008751:Methylene Blue