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Study of telomerase reverse transcriptase (hTERT) expression in normal, aged, and photo‐aged skin
Author(s) -
Attia Enas A. S.,
Seada Laila S.,
ElSayed Mahira H.,
ElShiemy Saleh M.
Publication year - 2010
Publication title -
international journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 93
eISSN - 1365-4632
pISSN - 0011-9059
DOI - 10.1111/j.1365-4632.2009.04374.x
Subject(s) - telomerase , telomerase reverse transcriptase , telomere , senescence , medicine , skin aging , reverse transcriptase , germline , pathology , cancer research , biology , dermatology , genetics , rna , dna , gene
Background Telomerase is a ribonucleoprotein enzyme capable of extending chromosome ends with telomeric DNA sequences. It protects the germline and stem cells from senescence by preventing telomere attrition. Cutaneous aging includes intrinsic aging, and photo‐aging. Telomere‐associated cellular senescence contributes to certain age‐related cutaneous disorders, including increased cancer incidence. Premature skin aging in xeroderma pigmentosa (XP) is expected to show increased telomere attrition. We aimed to study human telomerase reverse transcriptase (hTERT) expression in normal, aged and photo‐aged skin and to investigate its possible role in the pathogenesis of aging and photo‐aging. Methods hTERT expression using immunohistochemistry was studied in 75 subjects comprising four groups: group I, 10 subjects with aged skin; group II, 20 subjects with photo‐aging; group III, Five patients with XP; and group IV, 40 subjects comprising the control groups. Results We found positive hTERT in normal skin and in the basal and sometimes in supra‐basal layers. We reported positive hTERT expression in dermal fibroblasts, histiocytes, and skin appendages (other than hair follicles) in some cases from all the studied groups. Photo‐aged and prematurely photo‐aged skin showed greater hTERT expression than young and aged skin. Conclusion Telomeres rather than telomerase are involved in cellular senescence. Yet, telomerase is intimately related to photo‐aging in which lifetime cumulative sun exposure is an important factor. However, genetic damage in XP is the decisive factor and not merely ultraviolet exposure.