Browsing by Subject "Telocytes"

Now showing 1 - 6 of 6
  • Thumbnail Image
    Publication
    Open Access
    Human resident CD34+ stromal cells/telocytes have progenitor capacity and are a source of αSMA+ cells during repair
    (F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2015) Díaz-Flores, L.; Gutiérrez, R.; García, M.P.; González, M.; Sáez, F.J.; Aparicio, F.; Díaz-Flores Jr., L.; Madrid Cuevas, Juan Francisco
    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.
  • Thumbnail Image
    Publication
    Open Access
    Morphofunctional basis of the different types of angiogenesis and formation of postnatal angiogenesis-related secondary structures
    (Universidad de Murcia. Departamento de Biología Celular e Histología, 2017) Díaz Flores, L.; Gutierrez, R.; García Suárez, M.P.; Sáez, F.J.; Gutiérrez, E.; Valladares, F.; Carrascosa, J.L.; Díaz Flores Jr, L.; Madrid Cuevas, Juan Francisco
    We review the morpho-functional basis of the different types of angiogenesis and report our observations, including the formation of angiogenesisrelated secondary structures. First of all, we consider the following issues: a) conceptual differences between angiogenesis and vasculogenesis, b) incidence of angiogenesis in pre- and postnatal life, c) regions of vascular tree with angiogenic capacity, d) cells (endothelial cells, pericytes, CD34+ adventitial stromal cells of the microvasculature and inflammatory cells) and extracellular matrix components involved in angiogenesis, e) events associated with angiogenesis, f) different types of angiogenesis, including sprouting and intussusceptive angiogenesis, and other angiogenic or vascularization forms arising from endothelial precursor cells (postnatal vasculogenesis), vasculogenesis mimicry, vessel co-option and piecemeal angiogenesis. Subsequently, we consider the specific morphofunctional characteristics of each type of angiogenesis. In sprouting angiogenesis, we grouped the events in three phases: a) activation phase, which includes vasodilation and increased permeability, EC, pericyte and CD34+ adventitial stromal cell activation, and recruitment and activation of inflammatory cells, b)sprouting phase, encompassing EC migration (concept and characteristics of endothelial tip cells, tip cell selection, lateral inhibition, localized filopodia formation, basal lamina degradation and extracellular changes facilitating EC migration), EC proliferation (concept of endothelial stalk cells), pericyte mobilization, proliferation, recruitment and changes in CD34+ adventitial stromal cells and inflammatory cells, tubulogenesis, formation of a new basal lamina, and vascular anastomosis with capillary loop formation, and c) vascular remodelling and stabilization phase (concept of phalanx cells). Subsequently, the concept, incidence, events and mechanisms are considered in the other forms of angiogenesis. Finally, we contribute the formation of postnatal angiogenesis-related secondary structures: a) intravascular structures through piecemeal angiogenesis, including intravascular papillae in vessel tumours and pseudotumours (intravascular papillary endothelial hyperplasia, vascular transformation of the sinus in lymph nodes, papillary intralymphatic angioendothelioma or Dabska tumour, retiform hemangioendothelioma, hemangiosarcoma and lymphangiosarcoma), vascular septa in hemorrhoidal veins and intravascular projections in some tumours; b) arterial intimal thickening; c) intravascular tumours and pseudotumours (e.g. intravenous pyogenic granulomas and intravascular myopericytoma); d) vascular glomeruloid proliferations; and e) pseudopalisading necrosis in glioblastoma multiform.
  • Thumbnail Image
    Publication
    Open Access
    Telocytes and lung disease
    (Universidad de Murcia. Departamento de Biología Celular e Histología, 2016) Song, Dongli; Cretoiu, Dragos; Cretoiu, Sanda M.; Wang, Xiangdong
    Telocytes (TCs) represent a new distinct type of interstitial cells found in many organs, including lungs. TCs are mainly defined by a small cellular body from which arise very long (hundreds of micrometers) extensions named telopodes. During the last years, TCs were characterized in respect with their microRNA profiles, gene features and proteome signatures. Also, the ultrastructural 3D configuration was further elucidated by the aid of the FIB-SEM technology. TCs are able to communicate by homo- and heterocellular contacts with neighboring cells and are also able to transfer genetic information and signaling molecules to influence other cells by means of extracellular vesicle release. However, the exact function of lung TCs remains unclear. Here, we review the potential significance of TCs in the pathogenesis of pulmonary diseases. We will also discuss some future possibilities for targeting TCs as a potential therapeutic strategy.
  • Thumbnail Image
    Publication
    Open Access
    Telocytes form networks in normal cardiac tissues
    (F. Hernandez y JuanF. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología., 2012) Rusu, Mugurel Constantin; Pop, F.; Hostiuc, S.; Curca, G.C.; Jianu, A.M.; Paduraru, D.
    Telocytes (TC) are a class of interstitial cells present in heart. Their characteristic feature is the presence of extremely long and thin prolongations (called telopodes). Therefore, we were interested to see whether or not TCs form networks in normal cardiac tissues, as previously suggested. Autopsy samples of cardiac tissues were obtained from 13 young human cadavers, without identifiable cardiac pathology and with a negative personal history of cardiovascular disease. Immunohistochemistry on formalin-fixed paraffin-embedded tissues was performed using monoclonal antibodies for CD117/c-kit. Additionally, ventricular samples from 5 Sprague-Dawley rats were ultrastructurally evaluated under transmission electron microscopy. We found c-kit positive cells with TC features in subepicardium, as well in subepicardial arteries and in subepicardial fat. TCs were also present in the subendocardium. Light and electron microscopy revealed the existence of intramyocardial networks built up by bipolar TCs. Larger c-kit positive multipolar TCs were found between cardiac muscle bundles. Our results support the existence of a cardiac network of telocytes.
  • Thumbnail Image
    Publication
    Open Access
    Telocytes in skeletal, cardiac and smooth muscle interstitium: morphological and functional aspects
    (Universidad de Murcia. Departamento de Biología Celular e Histología, 2018) Marini, Mirca; Rosa, Irene; iIbba Mannesch, Lidia; Manetti, Mirko
    Telocytes (TCs) represent a new distinct type of cells found in the stromal compartment of many organs, including the skeletal, cardiac and smooth muscles. TCs are morphologically defined as interstitial cells with a small cellular body from which arise very long (up to hundreds of micrometers) and thin moniliform processes (named telopodes) featuring the alternation of slender segments (called podomers) and small dilated portions (called podoms) accommodating some organelles. Although these stromal cells are mainly characterized by their ultrastructural traits, in the last few years TCs have been increasingly studied for their immunophenotypes, microRNA profiles, and gene expression and proteomic signatures. By their longdistance spreading telopodes, TCs build a threedimensional network throughout the whole stromal space and communicate with each other and neighboring cells through homocellular and heterocellular junctions, respectively. Moreover, increasing evidence suggests that TCs may exert paracrine functions being able to transfer genetic information and signaling molecules to other cells via the release of different types of extracellular vesicles. A close relationship between TCs and stem/progenitor cell niches has also been described in several organs. However, the specific functions of TCs located in the muscle interstitium remain to be unraveled. Here, we review the morphological and possible functional aspects of TCs in skeletal, cardiac and smooth muscle tissues. The potential involvement of TCs in muscle tissue pathological changes and future possibilities for targeting TCs as a novel promising therapeutic strategy to foster muscle tissue regeneration and repair are also discussed.
  • Thumbnail Image
    Publication
    Open Access
    Telocytes, a distinct type of cell among the stromal cells present in the lamina propria of jejunum
    (F. Hernández y Juan F. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología, 2012) Cretoiu, D.; Cretoiu, Sanda M.; Simionescu, Anca A.; Popescu, L.M.
    Conventionally, cells described in the stroma of the intestinal wall are fibroblasts/fibrocytes, mast cells, plasma cells, eosinophils, macrophages and, interstitial cells of Cajal (ICCs), the latter being considered as the pacemakers of gastrointestinal rhythmicity. Recently, a new type of stromal cell called telocyte (TCs) was found in various cavitary and non-cavitary organs (www.telocytes.com). We show here direct electron microscopical evidence for the presence of TCs in the lamina propria of rat jejunum just beneath the epithelial layer of the mucosal crypts and in between the smooth muscle cells (SMCs) of muscularis mucosae. TCs are characterized by: several very long (tens to hundreds of µm) prolongations called telopodes (Tps). Tps (with caliber below the resolving power of light microscopy) display podomeres (thin segments ≤0.2 µm) and podoms (dilations accommodating caveolae, mitochondria, and endoplasmic reticulum). Tps present dichotomous branching and form a three dimensional network close to immune cells, SMCs or nerve bundles. TCs could play a role in intercellular signaling and control of local tissue homeostasis