Role of the Pericorneal Papillary Structure in Renewal of Corneal Epithelium

Davanger, Martin; Evensen, Arne

doi:10.1038/229560a0

Cited by 570 publications

(334 citation statements)

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“…Before functional dimension can be addressed, it is necessary to understand where the limbal niche is. Anatomically, the limbal SC niche is located at the Palisades of Vogt (Figure 1), which is highly pigmented because of melanocytes [49][50][51], and is infiltrated with antigen-presenting Langerhan's cells [52] and suppressor T-lymphocytes [53]. Unlike that of the cornea, the basement membrane of the limbus is undulating with papillae or 'pegs' of stroma extending upward [54] and fenestrated [55,56]; these anatomic features in the limbus suggest that limbal epithelial SCs might closely interact with cells in the underlying limbal stroma (Figure 2).…”

Section: Where Is the Limbal Stem Cell Niche?mentioning

confidence: 99%

Niche regulation of corneal epithelial stem cells at the limbus

et al. 2007

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Among all adult somatic stem cells, those of the corneal epithelium are unique in their exclusive location in a defined limbal structure termed Palisades of Vogt. As a result, surgical engraftment of limbal epithelial stem cells with or without ex vivo expansion has long been practiced to restore sights in patients inflicted with limbal stem cell deficiency. Nevertheless, compared to other stem cell examples, relatively little is known about the limbal niche, which is believed to play a pivotal role in regulating self-renewal and fate decision of limbal epithelial stem cells. This review summarizes relevant literature and formulates several key questions to guide future research into better understanding of the pathogenesis of limbal stem cell deficiency and further improvement of the tissue engineering of the corneal epithelium by focusing on the limbal niche.

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Section: Where Is the Limbal Stem Cell Niche?mentioning

confidence: 99%

Niche regulation of corneal epithelial stem cells at the limbus

et al. 2007

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“…The structure of the palisades and the rete ridges, their vascularity and pigmentation are all analogous to repositories of SC in the monkey palm epidermis. [17][18][19] Several studies have indicated that migration of cells occurs in a centripetal manner from the limbus towards the centre of the cornea, not only in wound healing, but also during normal replicative epithelial turnover. This unidirectional movement from the limbus to the centre of the cornea points to the presence of a 'driving force' at the limbus.…”

Section: Clinical Evidence For Limbal Location Of Putative Corneal Epmentioning

confidence: 99%

“…43 Chung et al 44 extended these observations to show that the number of cells staining positive with this antibody increased after corneal wounding in rabbits. Basic research has identified several other attributes that are unique to the limbal epithelium (Table 1); for example, EGF receptors, 45,46 pigment, 17 cytokeratin profile (CK3/12 negative), 38,47 presence of vimentin, 48 CK19, and specific basement membrane characteristics. [49][50][51] Vimentin and CK19-positive, CK3-negative clusters of cells with unique electron microscopic morphology have been demonstrated.…”

Section: Clinical Evidence For Limbal Location Of Putative Corneal Epmentioning

confidence: 99%

Stem cell differentiation and the effects of deficiency

Dua

Joseph

Shanmuganathan

et al. 2003

Eye

193

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Stem cells have several unique attributes, the key features being their potency and plasticity. They have the ability to give rise to multiple cell lineages and to transdifferentiate into totally different cell type(s) when relocated to a novel stem cell niche. Most self-renewing tissues are served by stem cells. At the ocular surface, the corneo-scleral limbus is believed to provide the niche for corneal epithelial stem cells. A large body of circumstantial evidence, both clinical and basic, supports this view. However, specific identification of limbal stem cells has proved elusive. Cytokeratin markers, vimentin, epidermal growth factor receptors, p63, and others have been used to identify epithelial cell populations at the limbus, which could harbour putative stem cells. In contrast, none of the known haematopoietic stem cell markers namely, CD34 and CD133, stain any specific subset of corneal or limbal epithelial cells. Singly or collectively, none of these markers point to any unique cell(s) that could be regarded as stem cells, supporting the notion that the corneal epithelium is served by 'committed progenitors' rather than by stem cells. Disease or destruction of the corneoscleral limbus is associated with consequential events that eventually lead to visual impairment or blindness. Conjunctivalisation and vascularisation of the corneal surface and persistent or recurring epithelial defects are hallmarks of limbal deficiency.

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“…In early postnatal life, proliferating cells are found throughout the basal corneal epithelium (Tseng et al, 1999;Yew et al, 2001). However, as shown in Figure 1, the mass of the adult corneal epithelium is maintained by a population of stem-like cells in the basal limbal region (limbal stem cells) that continue to cycle slowly throughout life, unless stimulated to proliferate more rapidly by corneal injury (Davanger and Evensen, 1971;Cotsarelis et al, 1989). Their daughters (transit or transient amplifying cells) migrate centripetally (Kinoshita et al, 1981;Buck, 1985) into the basal layer of the corneal epithelium, where they continue to divide a small number of times (Kruse, 1994;Lehrer et al, 1998).…”

Section: Introductionmentioning

confidence: 99%