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Potten CS. Keratinocyte stem cells, label-retaining cells and possible genome protection mechanisms. J Investig Dermatol Symp Proc 2004; 9:183-95. [PMID: 15369212 DOI: 10.1111/j.1087-0024.2004.09305.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
Stem cells are the crucial cells upon which the entire tissue is dependent. Here we define and discuss what is meant by and known about keratinocyte stem cells. One way in which these cells have been studied is by their ability to retain radioactivity labelled thymidine for long periods of time (label retaining cells, LRCs). The underlying mechanism has been assumed in the past to be slow cycling but a more likely explanation is the selective segregation of old and new DNA strands (Cairns's hypothesis). Experiments in the small intestine indicate that the stem cells here are selectively sorting their DNA and becoming LRCs. A possible role for p53 in stem cell biology is presented.
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Mihara M. Scanning electron microscopy of skin surface and the internal structure of corneocyte in normal human skin. An application of the osmium-dimethyl sulfoxide-osmium method. Arch Dermatol Res 1988; 280:293-9. [PMID: 3178286 DOI: 10.1007/bf00440603] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A horny layer of normal human skin prepared according to the newly developed osmium-dimethyl sulfoxide-osmium method was examined using scanning electron microscopy. On the skin surface, cytomembranes of the uppermost corneocytes frequently had unilateral, very slightly flat-elevated, zonal areas along the junctions between the corneocytes. The uppermost corneocytes peeled off along the junctions, leaving the remnants of their cell bodies in the junctional areas. In the cracked surface, cytomembranes of the corneocytes protruded from the plane of their cytoplasmic surface. In the lateral junction between the corneocytes, the cytomembranes of the corneocytes were in tight contact with each other, while occasionally the marginal bands had become detached from the cytomembranes. In the vertical connection, cleavages formed between the cytomembranes of the corneocytes. There were thick woollen thread-like structures about 10-30 nm thick in the cytoplasm of the corneocytes. They formed fine irregular meshworks, with their tips projecting digitally: Transmission electron microscopy revealed these structures as most likely being keratin bundles transformed during processing.
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Affiliation(s)
- M Mihara
- Department of Dermatology, Tottori University School of Medicine, Yonago, Japan
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Bickenbach JR, McCutecheon J, Mackenzie IC. Rate of loss of tritiated thymidine label in basal cells in mouse epithelial tissues. CELL AND TISSUE KINETICS 1986; 19:325-33. [PMID: 3719664 DOI: 10.1111/j.1365-2184.1986.tb00684.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A subpopulation of epithelial cells which retains a tritiated thymidine label (termed label-retaining cells, LRCs) has been previously demonstrated in skin and oral mucosae of mice and hamsters. To examine the rate of decrease in the number of LRCs and the changes in degree of labelling, young mice were labelled with tritiated thymidine and the rate at which label was diluted from basal keratinocytes assessed for up to 90 days. The number of LRCs in each tissue examined decreased from 15 to 90 days after labelling with the epidermal tissues maintaining a higher percentage of LRCs than the oral mucosae. Grain counts for LRCs in each tissue at each time period indicated that the number of silver grains overlying LRCs also decreased with time. The observed decrease in numbers of LRCs and the change in their degree of labelling with time suggest that such cells divide slowly, a property associated with stem cells.
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Hume WJ. A theoretical consideration of some biological parameters involved in cell kinetic investigations of oral leukoplakia and abnormal states in stratified squamous epithelium. JOURNAL OF ORAL PATHOLOGY 1981; 10:375-85. [PMID: 6801233 DOI: 10.1111/j.1600-0714.1981.tb01289.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Johannesson A, Hammar H. The rate of corneocyte formation in microscopic lesions in patients with active psoriasis. Br J Dermatol 1981; 105:391-404. [PMID: 7295551 DOI: 10.1111/j.1365-2133.1981.tb00770.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Microscopic lesions in active psoriasis were identified after careful examination with a magnifying glass in areas free of macroscopic lesions and of hair follicles. Biopsies were excised without anesthesia, immediately frozen and cryostat-sectioned. Care was taken to preserve the horny layer which was stained to reveal corneocyte membranes and nuclei when present. The interlocking sheets of corneocyte layers made it feasible to outline and trace intercellular spaces parallel to the surface and count the number of corneocyte layers between pairs of these. It was assumed that the location of such a space in the horny layer indicates the period of time from its formation. This information was used to assess the rate of corneocyte layer formation at specified intervals of time. The result shows that adjacent areas of the horny layer could be compared and relative rates of corneocyte layer formation computed. In the parakeratotic part of the early lesions of psoriasis studied the rate of corneocyte layer formation was 15 times higher than that in the non-involved skin. The peak rate, coincident with parakeratosis, was preceded by a number of thickened corneocyte layers. These also showed an increased rate of formation, up to 6.6 times that in non-involved skin. There was no acanthosis in the lesions studied. A subepidermal cellular infiltrate was observed. Periods of rapid corneocyte formation with parakeratosis were often short (not more than one day). These were interrupted by periods with a lower rate. The relationship between corneocyte morphology and stratum corneum kinetics is a distinct feature in the early psoriatic lesion.
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Potten CS. Cell replacement in epidermis (keratopoiesis) via discrete units of proliferation. INTERNATIONAL REVIEW OF CYTOLOGY 1981; 69:271-318. [PMID: 6163744 DOI: 10.1016/s0074-7696(08)62326-8] [Citation(s) in RCA: 227] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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9
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Abstract
There is growing evidence that the basal layer of stratified squamous epithelia consists of cells of differing proliferative capacities and behaviour. These can be classified as stem cells, transient amplifying cells and post-mitotic maturing cells, the most important of which appear to be the stem cells which may be present throughout life and are responsible for all cell production under steady-state conditions. Recent stem cell concepts are reviewed for epidermis, intestinal crypt and oral mucosa and are compared with tissues such as bone marrow and testes which have for some time been thought to operate in a similar manner. These concepts are applied to several pathological conditions of oral epithelia in an attempt to explain some of the changes observed.
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Hölzle E, Plewig G. Effects of dermatitis, stripping, and steroids on the morphology of corneocytes. A new bioassay. J Invest Dermatol 1977; 68:350-6. [PMID: 864272 DOI: 10.1111/1523-1747.ep12496481] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
This study was designed to investigate the effects of increased or decreased epidermal turnover on the morphology of human corneocytes. The desquamating portion of the stratum corneum was sampled with the detergent scrub technique using Triton X-100. The following parameters were measured: size (surface micron2), shape (regular, irregular), nuclear inclusions, trabeculae, and numerical counts. Specimens were obtained from adult males with allergic contact dermatitis (N=18); with tretinoin-induced dermatitis (N=11); after cellophane stripping (N=11); and after treatment of these conditions with topical steroids (N=40). Data from 250,000 cells were analyzed statistically. The reproducibility of the method is good (r=0.934). Corneocytes from skin of patients with allergic contact dermatitis differed from those of normal skin: they were 15% smaller and of irregular shape with asymmetrical trabeculae; 50% were nucleated and about 3 times as many cells were collected per cm2 skin surface. Tretinoin and stripping produced similar but more pronounced effects. Topical steroids significantly improved all parameters (p less 0.01). Betamethasone-17-dipropionate was more effective than the valerate. This bioassay permits sensitive measurements of corneocyte morphology in conditions with altered epidermal cellular kinetics. It provides a method to evaluate steroid effectiveness.
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Abstract
The microscopical changes of plantar Str. corneum after immersion in alkaline were investigated. For this purpose a test system was used in which unexcised skin of guinea pig hind feet was exposed and subsequently analysed by the FITC-staining method. The effect of KOH on the Str. corneum consisted in an immediate swelling of the outer cell layers which was followed by a further increase in cell volume. Cells became separated layer by layer after maximal swelling. There is a high and constant rate of cell loss, when treated superficial cells are repeatedly removed as compared to permanent immersion. Thus, the buffering capacity of the treated outer cell layers has a rate limiting effect upon alkaline-induced cell loss in the Str. corneum.
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Abstract
The "keratolytic" effect of salicylic acid was examined in guinea-pig skin. Using a fluorescent staining method the str. corneum cells could be seen to rapidly become detached. The cellular walls remained unchanged. This drug therefore appears to primarily reduce the intercellular cohesiveness of the horny cells.
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Abstract
A tentative model is presented which is based on existing data and our own cell kinetic and morphological observations in mice. The model suggests that the epidermal Langerhans cell plays a role in proliferation control of keratinocytes and may also act as an epidermal stem cell.
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Potten CS, Allen TD. Control of epidermal proliferative units (EPUs). An hypothesis based on the arrangement of neighbouring differentiated cells. Differentiation 1975; 3:161-5. [PMID: 1237438 DOI: 10.1111/j.1432-0436.1975.tb00857.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Abstract
Recent reports on the ordered structure of the epidermis are reviewed. The regular relationship between Langerhans cells and cell columns in the mouse is not typical of the epidermis of other animals. The pattern of mitotic activity previously described in mouse epidermis has also been demonstrated in the hamster, which suggests control of keratinocyte activity rather than the exclusion of keratinocytes from the central region beneath cell columns. These findings are discussed in relation to mechanisms which may be responsible for the formation of cell columns.
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Hashimoto K. New methods for surface ultrastructure: Comparative studies of scanning electron microscopy, transmission electron microscopy and replica method. Int J Dermatol 1974; 13:357-81. [PMID: 4214793 DOI: 10.1111/j.1365-4362.1974.tb05068.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Potten CS. The epidermal proliferative unit: the possible role of the central basal cell. CELL AND TISSUE KINETICS 1974; 7:77-88. [PMID: 4129708 DOI: 10.1111/j.1365-2184.1974.tb00401.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Potten CS, Hendry JH. Letter: Clonogenic cells and stem cells in epidermis. INTERNATIONAL JOURNAL OF RADIATION BIOLOGY AND RELATED STUDIES IN PHYSICS, CHEMISTRY, AND MEDICINE 1973; 24:537-40. [PMID: 4543437 DOI: 10.1080/09553007314551441] [Citation(s) in RCA: 46] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Christophers E, Laurence EB. Regional variations in mouse skin: quantitation of epidermal compartments in two different body sites. VIRCHOWS ARCHIV. B, CELL PATHOLOGY 1973; 12:212-22. [PMID: 4196370 DOI: 10.1007/bf02893999] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Rasterelektronenmikroskopie an histologischem Material. Arch Dermatol Res 1973. [DOI: 10.1007/bf00595533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Morphologische Untersuchungen zur Proliferationskinetik der M�usehaut. Cell Tissue Res 1973. [DOI: 10.1007/bf00306708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Christophers E. Correlation between column formation, thickness and rate of new cell production in guinea pig epidermis. VIRCHOWS ARCHIV. B, CELL PATHOLOGY 1972; 10:286-92. [PMID: 4626459 DOI: 10.1007/bf02899739] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Hundeiker M. [Morphology of the stratum corneum]. ARCHIV FUR DERMATOLOGISCHE FORSCHUNG 1972; 244:86-9. [PMID: 4648778 DOI: 10.1007/bf00600135] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Karatschai M, Kinzel V, Goerttler K, Süss R. "Geography" of mitoses and cell divisions in the basal cell layer of mouse epidermis. ZEITSCHRIFT FUR KREBSFORSCHUNG UND KLINISCHE ONKOLOGIE. CANCER RESEARCH AND CLINICAL ONCOLOGY 1971; 76:59-64. [PMID: 4255590 DOI: 10.1007/bf00304287] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Christophers E, Braun-Falco O. Fluorescein-isothiocyanate as a stain for keratinizing epithelia. ARCHIV FUR DERMATOLOGISCHE FORSCHUNG 1971; 241:199-209. [PMID: 4106730 DOI: 10.1007/bf00595437] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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