scholarly journals The Role of Limbal Epithelial Stem Cells in Regulating Corneal (Lymph)angiogenic Privilege and the Micromilieu of the Limbal Niche following UV Exposure

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
M. Notara ◽  
A. Lentzsch ◽  
M. Coroneo ◽  
C. Cursiefen
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Damage ◽  
Lymphatic Vessels ◽  
Uv Exposure ◽  
Epithelial Stem Cells ◽  
Limbal Epithelium ◽  
Limbal Epithelial Stem Cells ◽  
Cell Niche

The cornea is a clear structure, void of blood, and lymphatic vessels, functioning as our window to the world. Limbal epithelial stem cells, occupying the area between avascular cornea and vascularized conjunctiva, have been implicated in tissue border maintenance, preventing conjunctivalisation and propagation of blood and lymphatic vessels into the cornea. Defects in limbal epithelial stem cells are linked to corneal neovascularisation, including lymphangiogenesis, chronic inflammation, conjunctivalisation, epithelial abnormalities including the presence of goblet cells, breaks in Bowman’s membrane, persistent epithelial defects and ulceration, ocular surface squamous neoplasia, lipid keratopathy, pain, discomfort, and compromised vision. It has been postulated that pterygium is an example of focal limbal deficiency. Previous reports showing changes occurring in limbal epithelium during pterygium pathogenesis suggest that there is a link to stem cell damage. In this light, pterygium can serve as a model disease of UV-induced stem cell damage also characterised by corneal blood and lymphangiogenesis. This review focuses on the role of corneal and limbal epithelial cells and the stem cell niche in maintaining corneal avascularity and corneal immune privilege and how this may be deregulated following UV exposure. We present an overview of the PUBMED literature in the field as well as recent work from our laboratories.

scholarly journals Stem Cell Niche Microenvironment: Review

2021 ◽  
Vol 8 (8) ◽  
pp. 108
Author(s):  
Mohamed Abdul-Al ◽  
George Kumi Kyeremeh ◽  
Morvarid Saeinasab ◽  
Saeed Heidari Keshel ◽  
Farshid Sefat
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Corneal Epithelium ◽  
Stem Cell Niche ◽  
Epithelial Stem Cells ◽  
Self Renewal ◽  
Human Corneal Epithelium ◽  
Limbal Epithelial Stem Cells ◽  
Cell Niche

The cornea comprises a pool of self-regenerating epithelial cells that are crucial to preserving clarity and visibility. Limbal epithelial stem cells (LESCs), which live in a specialized stem cell niche (SCN), are crucial for the survival of the human corneal epithelium. They live at the bottom of the limbal crypts, in a physically enclosed microenvironment with a number of neighboring niche cells. Scientists also simplified features of these diverse microenvironments for more analysis in situ by designing and recreating features of different SCNs. Recent methods for regenerating the corneal epithelium after serious trauma, including burns and allergic assaults, focus mainly on regenerating the LESCs. Mesenchymal stem cells, which can transform into self-renewing and skeletal tissues, hold immense interest for tissue engineering and innovative medicinal exploration. This review summarizes all types of LESCs, identity and location of the human epithelial stem cells (HESCs), reconstruction of LSCN and artificial stem cells for self-renewal.

Characterization of the Limbal Epithelial Stem Cell Niche: Novel Imaging Techniques Permit In Vivo Observation and Targeted Biopsy of Limbal Epithelial Stem Cells

Stem Cells ◽  
2007 ◽  
Vol 25 (6) ◽  
pp. 1402-1409 ◽  
Author(s):  
Alex J. Shortt ◽  
Genevieve A. Secker ◽  
Peter M. Munro ◽  
Peng T. Khaw ◽  
Stephen J. Tuft ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Stem Cell Niche ◽  
Imaging Techniques ◽  
Targeted Biopsy ◽  
Epithelial Stem Cells ◽  
Limbal Epithelial Stem Cells ◽  
Cell Niche

scholarly journals Stem Cells in the Path of Light, from Corneal to Retinal Reconstruction

Biomedicines ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 873
Author(s):  
Ovidiu Samoila ◽  
Lacramioara Samoila
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Clinical Success ◽  
Corneal Stroma ◽  
Cell Transplant ◽  
Inclusion Criteria ◽  
Epithelial Stem Cells ◽  
Corneal Epithelial ◽  
Stem Cells Transplantation ◽  
Limbal Epithelial Stem Cells

The future of eye reconstruction invariably includes stem cells transplantation. Corneal limbus, corneal stroma, trabeculum, retinal cells, optic nerve, and all structures that are irreversibly damaged and have no means to be repaired or replaced, through conventional treatment or surgery, represent targets for stem cell reconstruction. This review tries to answer the question if there is any clinical validation for stem therapies, so far, starting from the cornea and, on the path of light, arriving to the retina. The investigation covers the last 10 years of publications. From 2385 published sources, we found 56 clinical studies matching inclusion criteria, 39 involving cornea, and 17 involving retina. So far, corneal epithelial reconstruction seems well validated clinically. Enough clinical data are collected to allow some form of standardization for the stem cell transplant procedures. Cultivated limbal epithelial stem cells (CLET), simple limbal epithelial transplant (SLET), and oral mucosa transplantation are implemented worldwide. In comparison, far less patients are investigated in retinal stem reconstructions, with lower anatomical and clinical success, so far. Intravitreal, subretinal, and suprachoroidal approach for retinal stem therapies face specific challenges.

scholarly journals Maintenance of Adult Stem Cells: Role of the Stem Cell Niche

2011 ◽  
pp. 35-55 ◽  
Author(s):  
Yoshiko Matsumoto ◽  
Hiroko Iwasaki ◽  
Toshio Suda
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Stem Cell Niche ◽  
Adult Stem Cells ◽  
Cell Niche

Targeting on the Stem Cell Niche Can Protect Hematopoietic Stem Cell from Chemotherapy and G-CSF

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 5790-5790
Author(s):  
Sidan Li ◽  
Qiongli Zhai ◽  
Dehui Zou ◽  
Changhong Li ◽  
Lugui Qiu
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Mouse Models ◽  
Cell Function ◽  
Conflicts Of Interest ◽  
Hematopoietic Stem ◽  
Transplant Patients ◽  
Cell Engraftment ◽  
Cell Niche

Abstract The majority of hematopoietic stem/progenitor cells (HSPCs) reside in the bone marrow surrounded by specialized bone-shielded environment. The specialized microenvironment or niche not only provides a favorable habitat for HSPC maintenance and development but also governs stem cell function. Here we investigated the potential role of bone remodeling osteoblasts and osteoclasts in homeostasis and stress-induced mobilization of hematopoietic progenitors, then further tested the hypothesis that targeting the niche might improve stem cell–based therapies using six mouse models to mimic the multiple rounds of chemotherapy followed by autologous hematopoietic stem cells (HSCs) transplantation in a clinical setting. Herein, we show that multiple rounds treatment of cytotoxic drugs influence niche. Serum osteocalcin level declined obviously (22.19 ± 1.08 ng/mL, before treatment vs 16.08 ± 2.12 ng/mL, steady state, P=0.01) in autologous HSPCs transplant patients. In mouse models, the number of CD45- Ter119- OPN+ osteoblast was significantly reduced (untreated, 3993 ± 129 cells/femur; CTLs, 1937 ±196 cells/femur; Gs, 1055 ± 43 cells/femur; P<0.01). Pharmacologic use of parathyroid hormone (PTH) or receptor activator of nuclear factor kappa-B ligand (RANKL) increases the number of HSC mobilized into the peripheral blood for stem cell harvests and protects stem cells from repeated exposure to cytotoxic chemotherapy. Ttreatment with granulocyte colony stimulating factor (G-CSF) plus PTH led to relative preservation of the HSC pool (G vs PTH, P<0.01; CTL vs PTH, P<0.05). Recipient mice transplanted with circulation HSPCs of P+R and P+R+G groups also showed more robust myeloid and lymphatic cell engraftment than did HSCs from either CTL or G group. These data provide evidence that targeting the HSPC niche may improve the efficacy of HSPC mobilization. Disclosures No relevant conflicts of interest to declare.

scholarly journals Characterization of putative stem cells in isolated human colonic crypt epithelial cells and their interactions with myofibroblasts

2009 ◽  
Vol 296 (2) ◽  
pp. C296-C305 ◽  
Author(s):  
S. Samuel ◽  
R. Walsh ◽  
J. Webb ◽  
A. Robins ◽  
C. Potten ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Epithelial Cells ◽  
Side Population ◽  
Cell Types ◽  
Population Characteristics ◽  
Colonic Crypt ◽  
Epithelial Stem Cells ◽  
Colonic Crypts ◽  
Cell Niche

Colonic epithelial stem cells are believed to be located at the crypt base where they have previously been shown to express musashi-1. The colonic stem cell niche, which includes extracellular matrix and myofibroblasts (together with other cell types), is likely to be important in maintaining the function of the progenitor cells. The aims of our studies were to characterize stem cells in isolated and disaggregated human colonic crypt epithelial cells and investigate their interactions with monolayers of primary human colonic myofibroblasts. In unfractionated preparations of disaggregated colonic crypts, musashi-1 positive cells preferentially adhered to colonic myofibroblasts, despite the presence of excess blocking anti-β1-integrin antibody. These adherent epithelial cells remained viable for a number of days and developed slender processes. Cells with side population characteristics (as demonstrated by ability to expel the dye Hoechst 33342) were consistently seen in the isolated colonic crypt epithelial cells. These side population cells expressed musashi-1, β1-integrin, BerEP4, and CD133. Sorted side population crypt epithelial cells also rapidly adhered to primary colonic myofibroblasts. In conclusion, in preparation of isolated and disaggregated human colonic crypts, cells with stem cell characteristics preferentially adhere to primary human colonic myofibroblasts in a β1-integrin-independent fashion.

scholarly journals Limbal stem cell deficiency: etiology, pathogenesis, priniciples and prospects of surgical treatment

2019 ◽  
Vol 12 (1) ◽  
pp. 103-111
Author(s):  
A. S. Dubovikov ◽  
I. O. Gavrilyuk ◽  
A. N. Kulikov ◽  
S. V. Churashov ◽  
V. F. Chernysh ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Surgical Treatment ◽  
Ex Vivo ◽  
Epithelial Stem Cells ◽  
Limbal Stem Cells ◽  
History Of Development ◽  
History Of ◽  
Limbal Epithelial Stem Cells ◽  
Limbal Stem Cell

The review is focused on the modern view of the etiology and pathogenesis of limbal stem cells deficiency. The history of development of tissue and ex-vivo transplantation of limbal epithelial stem cells is presented. Certain promising directions of the treatment of patients with limbal stem cells deficiency are presented.

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