Telocytes in liver: electron microscopic and immunofluorescent evidence

Telocytes (TCs) are a brand-new cell type frequently observed in the interstitial space of many organs (see www.telocytes.com). TCs are defined by very long (tens of micrometers) and slender prolongations named telopodes. At their level, dilations—called podoms (~300 nm), alternate with podomers (80–100 nm). TCs were identified in a myometrial interstitial cell culture based on morphological criteria and by CD34 and PDGF receptor alpha (PDGFRα) immunopositivity. However, the mechanism(s) of telopodes formation and/or elongation and ramification is not known. We report here the low-level laser stimulation (LLLS) using a 1,064-nm neodymium-doped yttrium aluminum garnet (Nd:YAG) laser (with an output power of 60 mW) of the telopodal lateral extension (TLE) growth in cell culture. LLLS of TCs determines a higher growth rate of TLE in pregnant myometrium primary cultures (10.3 ± 1.0 μm/min) compared to nonpregnant ones (6.6 ± 0.9 μm/min). Acute exposure (30 min) of TCs from pregnant myometrium to 1 μM mibefradil, a selective inhibitor of T-type calcium channels, determines a significant reduction in the LLLS TLE growth rate (5.7 ± 0.8 μm/min) compared to LLLS per se in same type of samples. Meanwhile, chronic exposure (24 h) completely abolishes the LLLS TLE growth in both nonpregnant and pregnant myometria. The initial direction of TLE growth was modified by LLLS, the angle of deviation being more accentuated in TCs from human pregnant myometrium than in TCs from nonpregnant myometrium. In conclusion, TCs from pregnant myometrium are more susceptible of reacting to LLLS than those from nonpregnant myometrium. Therefore, some implications are emerging for low-level laser therapy (LLLT) in uterine regenerative medicine.

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“…Our findings are in correlation with recent data suggesting that PDGFRα-positive and CD34-positive cells are the same cell type—the TCs [6–8]. …”

Section: Discussionsupporting

confidence: 93%

Near-infrared low-level laser stimulation of telocytes from human myometrium

et al. 2014

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“…Telocytes have been detected in many organs , and we recently identified renal TCs in the renal cortex . However, the biological function of these cells remains unknown.…”

Section: Discussionmentioning

confidence: 99%

Renal telocytes contribute to the repair of ischemically injured renal tubules

Lin

et al. 2014

J Cellular Molecular Medi

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Telocytes (TCs), a distinct type of interstitial cells, have been identified in many organs via electron microscopy. However, their precise function in organ regeneration remains unknown. This study investigated the paracrine effect of renal TCs on renal tubular epithelial cells (TECs) in vitro, the regenerative function of renal TCs in renal tubules after ischaemia–reperfusion injury (IRI) in vivo and the possible mechanisms involved. In a renal IRI model, transplantation of renal TCs was found to decrease serum creatinine and blood urea nitrogen (BUN) levels, while renal fibroblasts exerted no such effect. The results of histological injury assessments and the expression levels of cleaved caspase-3 were consistent with a change in kidney function. Our data suggest that the protective effect of TCs against IRI occurs via inflammation-independent mechanisms in vivo. Furthermore, we found that renal TCs could not directly promote the proliferation and anti-apoptosis properties of TECs in vitro. TCs did not display any advantage in paracrine growth factor secretion in vitro compared with renal fibroblasts. These data indicate that renal TCs protect against renal IRI via an inflammation-independent pathway and that growth factors play a significant role in this mechanism. Renal TCs may protect TECs in certain microenvironments while interacting with other cells.

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“…Furthermore, increasing evidence has demonstrated the presence of TCs within stem cell niches [23,29,31,49,56,57] and indicated the potential involvement of TCs in tissue regeneration/repair after injury [32,38,[58][59][60][61][62][63][64]. Our group has recently identified the presence of TCs in liver [54], and further demonstrated a close relationship between TCs and the cells (hepatocytes/stem cells) essentially involved in liver regeneration using a murine model of partial hepatectomy [65]. The aim of the present study was to likewise investigate the possible roles of TCs in hepatic adaptions to pregnancy.…”

Section: Introductionmentioning

confidence: 99%

Telocytes in Pregnancy-Induced Physiological Liver Growth

Wang

Bei

Zhao

et al. 2015

Cell Physiol Biochem

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Background/Aims: We previously documented the presence of Telocytes (TCs) in liver and further indicated the potential roles of TCs in liver regeneration after hepatectomy. Pregnancy-induced liver growth, other than liver regeneration after hepatectomy, is a physiological hepatic adaption to meet the enhanced nutritional and metabolic demands. However, the possible roles of TCs in pregnancy-induced liver growth remain unknown. Methods: Pregnant mice were sacrificed at different time points (pregnancy day 0.5, 4.5, 8.5, 10.5, 12.5, 14.5, 16.5, and 18.5). The liver weight was used to evaluate the liver growth during pregnancy. Hepatocytes proliferation was determined by albumin and 5-ethynyl-2'- deoxyuridine (EdU) double immunostaining while TCs were counted by double immunolabeling for CD34/PDGFR-α. Results: Pregnancy-induced liver growth was preceded by increased proliferation of hepatocytes at pregnancy day 4.5, 8.5, 14.5 and 16.5. Furthermore, the number of TCs in liver detected by double immunolabeling for CD34/PDGFR-α was significantly increased at pregnancy day 4.5 and day 14.5, that was coincident with the occurrence of two peaks of hepatic cell proliferation during pregnancy. Conclusion: Our results suggest a possible relationship between TCs and hepatocyte proliferation in pregnancy-induced liver growth.

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Telocytes in liver: electron microscopic and immunofluorescent evidence

Cited by 87 publications

References 30 publications

Near-infrared low-level laser stimulation of telocytes from human myometrium

Near-infrared low-level laser stimulation of telocytes from human myometrium

Renal telocytes contribute to the repair of ischemically injured renal tubules

Telocytes in Pregnancy-Induced Physiological Liver Growth

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