Gopa Majmudar

Restoration of Collagen Formation in Photodamaged Human Skin by Tretinoin (Retinoic Acid)

BACKGROUND Topical tretinoin (retinoic acid) modifies fine wrinkles and certain other features of human skin damaged by exposure to the sun (photodamage), but histologic changes do not account for this improvement. In mice with photodamage induced by ultraviolet light, effacement of fine wrinkles by tretinoin is correlated with dermal collagen synthesis but not with histologic changes. We investigated whether collagen synthesis was reduced in photodamaged human skin and, if so, whether it could be restored by treatment with topical tretinoin. METHODS Biopsies of photodamaged skin from the extensor aspect of the forearm and skin from the buttocks, which had been protected from the sun, were performed on 26 healthy subjects. In addition, 29 patients with photodamaged skin were treated for 10 to 12 months with a daily application of 0.1 percent tretinoin cream (15 patients) or vehicle cream (14 patients). Skin-biopsy specimens obtained at base line and after treatment were assessed immunohistologically for evidence of dermal collagen I formation (collagen synthesis). RESULTS Collagen I formation was 56 percent less in the papillary dermis of photodamaged skin than in skin protected from the sun (P < 0.001) and was correlated with the clinical severity of photodamage (r = -0.58, P = 0.002). Treatment of photodamaged skin with tretinoin produced an 80 percent increase in collagen I formation, as compared with a 14 percent decrease in collagen formation with the use of vehicle alone (P = 0.006). CONCLUSIONS The formation of collagen I is significantly decreased in photodamaged human skin, and this process is partly restored by treatment with tretinoin.

Pilot histologic and ultrastructural study of the effects of medium-depth chemical facial peels on dermal collagen in patients with actinically damaged skin

BACKGROUND Chemical peels are employed for a variety of benign and premalignant skin disorders. OBJECTIVE We compared clinical and histologic features with ultrastructural changes that occur after medium-depth chemical facial peel. METHODS Three men with actinically damaged facial skin underwent a single 35% trichloroacetic acid peel. Biopsy specimens were taken before the peel, and 2 weeks and 3 months after the peel, for histologic examination, electron microscopy, and gel electrophoresis to assess total collagen type I content. RESULTS Clinical resolution of actinic damage corresponded with restoration of epidermal polarity. Collagen type I was markedly increased after the peel. Characteristic ultrastructural features of skin after peeling include markedly decreased epidermal intracytoplasmic vacuoles, decreased elastic fibers, and increased activated fibroblasts. CONCLUSION Electron microscopic studies after a medium-depth chemical peel of photodamaged skin reveal more profound changes than those seen histologically.

A comparison of wire brush and diamond fraisesuperficial dermabrasion for photoaged skin

Background: Superficial dermabrasion has a proven beneficial effect on photoaged skin, but little is known about the differences between the two major modalities used in dermabrasion, the diamond fraise (DF) and the wire brush (WB). Objective: We compared the clinical, immunohistologic, and biochemical changes after superficial dermabrasion with DF and WB. Methods: Eight photoaged patients (mean age, 68 years; range, 49 to 80 years) underwentfacial dermabrasion to the level of the papillary dermis. Clinical assessments were performed at baseline and at 3 and 12 weeks after dermabrasion. Biopsy specimens were taken from both dermabraded halves at the same time points and assessed by routine histologic and immunohistologic examinations, Western blot analysis, and radioimmunoassay. Scoring of intracellular and extracellular transforming growth factor-β1 was based on a semiquantitative ordinal scale (0=no staining to 4=maximum staining) in half-unit increments. The score for each specimen represents the average of values obtained from four high-power fields. Results: Both methods of dermabrasion resulted in significant resolution of actinic keratoses, lentigines, and wrinkling. No statistical significance was noted between the two methods in regard to clinical efficacy. Significantly fewer milia occurred after DF than after WB. Solar elastosis decreased with both the WB and DF. Immunohistologic examination demonstrated a highly significant increase in papillary dermal fibroblast staining for amino terminal procollagen I (type I pN-collagen) at 3 weeks for both DF and WB compared to baseline. Staining at 12 weeks had decreased from the peak noted at week 3, but was still significantly increased from baseline. Western blotting of type I pN-collagen demonstrated a 5.4-fold ( p =0.01) increase from baseline at 3 weeks and a 4.9-fold ( p =0.002) increase at 12 weeks after dermabrasion with the WB. Similarly, the DF produced a 4.9-fold ( p =0.006) increase at 3 weeks and a 5.1-fold ( p =0.008) increase at 12 weeks after dermabrasion. Western blotting of amino terminal procollagen III (type III pN-collagen) showed a 6.1-fold ( p =0.07) increase from baseline at 3 weeks and a 3.9-fold ( p =0.04) increase at 12 weeks after dermabrasion with the DF. The WB showed a 3.8-fold ( p =0.07) increase from baseline at 3 weeks and a 5.1-fold ( p =0.05) increase at 12 weeks. Transforming growth factor-β1 demonstrated a significant increase in extracellular staining with DF (3.3±0.2) and WB (3.7±0.2) from baseline (1.2±0.2, p Conclusion: Superficial dermabrasion with DF and WP appears to be similarly efficaciousin the treatment of photoaged skin. Significant increases in type I pN-collagen, type III pN-collagen, and TGF-β1 occurred in the papillary dermis after both types of dermabrasion. These results suggest that increased fibroblast activity and consequent collagen I and III synthesis underlie the clinical improvement.