Division of Cellular and Molecular Medicine, Carol Davila University of Medicine and Pharmacy, Bucharest 050474, Romania.
Reproduction. 2013 Apr 15;145(4):357-70. doi: 10.1530/REP-12-0369. Print 2013 Apr.
Telocytes (TCs) have been described in various organs and species (www.telocytes.com) as cells with telopodes (Tps) - very long cellular extensions with an alternation of thin segments (podomers) and dilated portions (podoms). We examined TCs using electron microscopy (EM), immunohistochemistry (IHC), immunofluorescence (IF), time-lapse videomicroscopy and whole-cell patch voltage clamp. EM showed a three-dimensional network of dichotomous-branching Tps, a labyrinthine system with homocellular and heterocellular junctions. Tps release extracellular vesicles (mean diameter of 160.6±6.9 nm in non-pregnant myometrium and 171.6±4.6 nm in pregnant myometrium), sending macromolecular signals to neighbouring cells. Comparative measurements (non-pregnant and pregnant myometrium) of podomer thickness revealed values of 81.94±1.77 vs 75.53±1.81 nm, while the podoms' diameters were 268.6±8.27 vs 316.38±17.56 nm. IHC as well as IF revealed double c-kit and CD34 positive results. Time-lapse videomicroscopy of cell culture showed dynamic interactions between Tps and myocytes. In non-pregnant myometrium, patch-clamp recordings of TCs revealed a hyperpolarisation-activated chloride inward current with calcium dependence and the absence of L-type calcium channels. TCs seem to have no excitable properties similar to the surrounding smooth muscle cells (SMCs). In conclusion, this study shows the presence of TCs as a distinct cell type in human non-pregnant and pregnant myometrium and describes morphometric differences between the two physiological states. In addition, we provide a preliminary in vitro electrophysiological evaluation of the non-pregnant state, suggesting that TCs could influence timing of the contractile activity of SMCs.
我们使用电子显微镜（EM）、免疫组织化学（IHC）、免疫荧光（IF）、延时视频显微镜和全细胞膜片钳技术检查了 TC。EM 显示出具有二分叉 Tp 的三维网络，具有同质和异质连接的迷宫系统。Tp 释放细胞外囊泡（在非妊娠子宫肌中直径为 160.6±6.9nm，在妊娠子宫肌中直径为 171.6±4.6nm），向邻近细胞发送大分子信号。对 podomer 厚度进行的比较测量（非妊娠和妊娠子宫肌）显示出 81.94±1.77nm 与 75.53±1.81nm 的值，而 podoms 的直径分别为 268.6±8.27nm 和 316.38±17.56nm。IHC 和 IF 均显示双 c-kit 和 CD34 阳性结果。细胞培养的延时视频显微镜显示了 Tp 和心肌细胞之间的动态相互作用。在非妊娠子宫肌中，TC 的膜片钳记录显示具有钙依赖性的超极化激活氯内向电流和不存在 L 型钙通道。TC 似乎没有类似于周围平滑肌细胞（SMC）的可兴奋特性。总之，这项研究表明在人非妊娠和妊娠子宫肌中存在 TC 作为一种独特的细胞类型，并描述了两种生理状态之间的形态计量学差异。此外，我们提供了非妊娠状态下的初步体外电生理学评估，表明 TC 可能影响 SMC 收缩活动的时间。
