Epithelial expression of cytokeratins 15 and 19 in vitiligo.

BACKGROUND: Cytokeratins (CK) belong to the family of intermediate filament proteins, and among them specific epithelial keratins are considered markers for stem cells activation. OBJECTIVES: This study aims to investigate the expression of CK15 and CK19 as possible stem cell markers in vitiligo during phototherapy. METHODS: The study was conducted on vitiligo patients receiving narrow-band ultraviolet therapy. Immunohistochemical staining for CK15 and CK19 was carried out, and clinical follow-up continued for 4 weeks. RESULTS: Of 28 patients, CK15 expression was demonstrated in 17 cases (61%) while CK19 expression was demonstrated in 11 cases (39%). Cells expressing positive staining were demonstrated in follicular and interfollicular epithelium. Expression was clearly demonstrated in patients younger than 20 years old, with shorter disease duration, with disease stability, and with normally pigmented hairs. Expression of cytokeratins was significantly correlated to improvement of vitiligo lesions. CONCLUSION: CK15 and CK19 are expressed in vitiligo during UV repigmentation in the follicular and interfollicular epithelium. This expression of cytokeratins was significantly correlated to improvement and can be considered valuable tool to monitor stem cells stimulation for the sake of the repigmentation process in vitiligo.

Effect of topical tretinoin, chemical peeling and dermabrasion on p53 expression in facial skin.

The tumour suppressor protein p53 is a phosphoprotein that is activated by DNA damage. It is involved in the decision whether the cells should stop replication and proceed to repair their DNA, or to die by apoptosis. In the present study, we evaluate the effect of some treatment modalities on the expression of p53 in facial skin. Biopsy specimens were obtained from the facial skin of 20 patients before and after treatment using topical tretinoin (11 cases), TCA chemical peeling (5 cases) and dermabrasion (4 cases). Biopsy specimens were also obtained from 12 control subjects representing the same age groups of the patients. Topical tretinoin therapy was found to induce a significant decrease in the expression of p53 up to 6 months of therapy followed by a significant increase after 10 months of therapy. On the contrary, superficial TCA peeling did not induce any statistically significant change in the expression of p53. On the other hand dermabrasion was found to induce a significant decrease in the level of expression of p53 in biopsies obtained after complete re-epithelialization followed by a significant increase. These changes in the expression of p53 may play a role in mediating the effects of such treatment modalities on the epidermis, as well as prevention of actinic neoplasia by adjusting any disturbance in the proliferation/apoptosis balance observed in photoaged facial skin.

Trichloroacetic acid peeling versus dermabrasion: a histometric, immunohistochemical, and ultrastructural comparison.

BACKGROUND: Trichloroacetic acid (TCA) chemical peel and dermabrasion are beneficial methods for treatment of photoaged skin. OBJECTIVE: In this study, we evaluated the changes induced by these therapies on various structures of facial skin of nine dark-skinned patients (Fitzpatrick types IV-V; TCA, five patients; dermabrasion, four patients) demonstrating different degrees of photodamage. METHODS: Routine histopathology coupled with histometric computer-assisted image analysis was used to assess epidermal changes. Alcian blue stain was used to evaluate changes in glycosaminoglycans. Immunoperoxidase techniques with antibodies against types I and III collagen and elastin were used to evaluate quantitatively changes in collagen and elastic fibers, and their ultrastructure was examined by transmission electron microscopy. RESULTS: Similar histologic, immunohistochemical, as well as ultrastructural changes were observed in the two groups, including epidermal and dermal rejuvenation with new collagen deposition and normalization of the elastic tissue. However, these changes were more prominent in patients treated with dermabrasion than those treated with TCA. CONCLUSION: The results of this study suggest that beneficial effects of such modalities on facial skin were accomplished primarily by increasing the amounts of collagen I and collagen III and improving the morphologic appearance of collagen and elastic fibers.

Effect of topical tretinoin on photoaged facial skin: a histometric, immunohistochemical and ultrastructural study.

BACKGROUND: Topical tretinoin is a recognized treatment for photoageing. AIM: To evaluate the microscopic changes induced by topical tretinoin used to treat mild to moderate photodamage in dark-skinned patients aged 30 to 50 years. PATIENTS AND METHODS: Biopsy specimens were obtained from the facial skin of 11 patients before and after treatment with topical tretinoin. Routine histopathology coupled with histometric computer-assisted image analysis was used to assess epidermal changes. Alcian blue stain was used to measure changes in glycosaminoglycans (GAGs). Immunoperoxidase technique for type I and III collagens and elastin, as well as transmission electron microscopy, were used to measure changes in collagen and elastic fibres. RESULTS: Epidermal hyperplasia occurs following tretinoin application, which is reversible with continued therapy. GAGs decreased (p < 0.05) after 6 months of tretinoin application but with no significant change thereafter. Quantitatively, there was an insignificant decrease of type I (p = 0.7) and III (p = 0.3) collagens during the first 6 months of tretinoin usage. However, biopsies taken after 10 months revealed a statistically significant increase in collagen I from a mean of 75.2% +/- 9.6 before treatment to 94.2% +/- 4.1 after treatment (p = 0.05). Similarly, the amount of type III collagen increased from a mean of 74.6% +/- 9.96 to 90.6% +/- 2.1 after 10 months of treatment (p = 0.05). On the other hand, the amount of elastin significantly (p = 0.02) decreased from a mean of 54.5% +/- 3.68 before treatment to 43.4% +/- 4.42 after 6 months of tretinoin application but with no significant change thereafter. Such changes were associated ultrastructurally with new collagen deposition and improvement of the quality of elastic fibres. CONCLUSION: Topical tretinoin benefits facial skin, mainly by increasing collagen I and III and also by improving the morphological appearance of collagen and elastic fibres.