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A correlation may exist between topical application of tretinoin and an increase in collagen I production in sun-damaged skin. The formation of collagen, a protein that is a component of connective tissue, is decreased in sun-damaged human skin. Skin biopsies were performed on 26 healthy, white participants. Analysis of biopsies from sun-protected areas of the buttocks and sun-damaged areas of the participants' forearms indicated that collagen I formation was significantly lessened in the damaged skin. An additional 29 white patients were randomly assigned to apply either a topical preparation of 0.1% tretinoin cream or a similar-looking placebo cream with no active ingredients. Some of the patients were treated for 10 months and some for 12 months. Biopsies were performed before treatment began and again at the end of treatment. Analysis of the biopsies found a 119% increase in collagen I staining of fibroblasts and an 80% increase in extracellular collagen I formation in patients treated with tretinoin. There was an 18% decrease in collagen staining of fibroblasts in patients who received the placebo.

Topical tretinoin (retinoic acid) may be an effective and safe treatment for hyperpigmented skin lesions in black individuals. Hyperpigmented skin lesions are dark, irregular spots that can occur after inflammation caused by acne, folliculitis, eczema or shaving irritation. Among 54 black individuals with hyperpigmented skin lesions, 24 were treated with topical tretinoin applied to the face or arms or both and 30 were treated with a placebo cream, or an inactive substance, every day for 40 weeks. Lesions were 40% lighter in the individuals treated with tretinoin after completion of treatment, compared with 18% lighter in the individuals treated with the placebo cream. Treatment with tretinoin reduced the melanin content of the lesions by 23%, compared with a 3% reduction after treatment with the placebo cream.

A 0.1 percent tretinoin cream applied to the skin may eliminate liver spots in some individuals. Liver spots are pigmented areas on the skin that are believed to be caused by long-term exposure to sunlight. Of 58 individuals with liver spots on their faces and arms, 28 applied the cream to affected areas every night, and 30 applied a cream that did not contain tretinoin. The appearance of their liver spots was assessed visually after two and four weeks of treatment and every month thereafter. A skin biopsy of a liver spot was performed in each individual before and after 10 months of treatment. After 10 months of treatment, significantly more patients in the tretinoin group experienced some lightening of their liver spots, compared with patients in the control group. Analysis of skin biopsies showed individuals using tretinoin had decreased pigmentation in the area of the liver spot.

Cyclosporine, an immunosuppressant drug often administered to organ transplant recipients, is also effective against some forms of psoriasis (a chronic skin disease involving plaques and scales). To learn more concerning the optimal dose of cyclosporine for treating this disorder, a 16-week controlled study of 85 patients was carried out. The patients had at least one fourth of their body surface covered by plaque-type psoriasis, or severe psoriasis that was disabling, and an unsatisfactory response to standard treatments for the disease (ultraviolet light or psoralen). Patients were randomly assigned to receive daily doses of 7.5 milligrams (15 patients), 5 milligrams (20 patients), or 3 milligrams (25 patients) of oral cyclosporine per kilogram of body weight. Twenty-five patients received an inactive drug (the control group). After the first eight weeks, patients who did not improve (including controls) were adjusted to the next higher dose (those at 7.5 mg/kg went up to 10 mg/kg). Three specific lesions on each patient were rated at regular intervals during the study for scaling, redness, plaque thickness, and overall severity. In addition, overall severity and extent of involvement of the body were rated. Kidney function (which is affected by cyclosporine in many people), blood pressure, white blood cell count, and other physiological variables were also evaluated. All patients who received cyclosporine improved more than patients who received the vehicle; for the three dose levels (from lowest to highest), the decrease in the psoriasis global scores was 39, 58, and 71 percent, respectively. The best effect was in the highest-dose group (80 percent clear or almost clear of lesions). Adjustments to higher doses were required for the largest proportion of patients in the lowest-dose group (65 percent). Four patients left the study because of side effects, and four required dose reduction. Effects on renal and neurologic function were noted. The results indicate that the best initial cyclosporine dose for treating plaque-type psoriasis is 5 milligrams per kilogram per day. Additional long-term studies are needed to evaluate the drug's safety and effectiveness. (Consumer Summary produced by Reliance Medical Information, Inc.)