In vivo study of skin mechanical properties in Raynaud''s phenomenon

BACKGROUND/AIM: Raynaud's phenomenon (RP) is usually the first symptom in patients with systemic sclerosis (SS) and may precede skin changes by several months or years. Non-invasive measurements of skin elasticity are very sensitive and appropriate for objective and quantitative evaluation of sclerodermatous skin. The aim of this study was to investigate and compare the mechanical properties of the skin in patients with primary, secondary, and suspected secondary RP. MATERIALS/METHODS: A total of 63 patients were studied. They were classified as having scleroderma-type nailfold capillary abnormalities--17 with indurative phase of scleroderma (group 1), nine with edematous phase of scleroderma (group 2), 18 with suspected secondary RP (group 3) and as having RP-type nailfold capillary abnormalities, 19 with primary RP (group 4). Thirty-nine sex- and age-matched healthy individuals with normal nailfold capillaroscopy pattern were also studied as controls. Mechanical properties of the skin were evaluated using a non-invasive suction device (Cutometer) equipped with a 2 mm probe. Measurements were performed over five anatomic regions: cheeks, volar forearms, wrists, hands, and proximal phalanx of the fingers. The skin mechanical parameters analyzed were distensibility (Uf), elasticity (Ua/Uf) and viscoelasticity (Uv/Ue). RESULTS: Most demonstrative changes were observed over volar forearms. Patients included in groups 1-3 were characterized by significantly lower Uf and higher Uv/Ue compared with patient group 4 and controls. Patient groups 1 and 2 showed significantly lower Ua/Uf, as well. There were no significant differences in skin mechanical parameters between patient group 4 and control group. CONCLUSION: Mechanical properties of the skin in patients with suspected secondary RP significantly differ from these in patients with primary RP and resemble those in patients with edematous phase of scleroderma. Our findings suggest that the non-invasive measurements of skin elasticity could be helpful in identifying patients with RP at risk of developing SS.     

Elastic properties of human skin: relation to age,sex, and anatomical region

Summary Using a recently developed noninvasive, in vivo suction device for measuring skin elasticity, we evaluated age, sex, and regional differences in the viscoelastic properties of skin. A total of 33 volunteers participated in the study consisting of (a) 8 young females, (b) 9 old females, (c) 8 young males and (d) 8 old males. Measurements were performed on 11 anatomical regions; three different loads were applied: 100,200, and 500 mbar. The parameters used were: immediate distension (Ue); delayed distension (Uv); immediate retraction (Ur); and, final deformation (Uf). To compare between subjects and anatomical regions, relative parameters independent of skin thickness were calculated: Uv/Ue, the ratio between the viscoelastic properties of skin and immediate distension, and Ur/Uf, which measures the ability of the skin to regain its initial position after deformation. Generally, Uv/Ue increased while Ur/Uf decreased with aging. Responses were variable with respect to load applied. Variability within anatomical regions was also noted. However, differences between the sexes were not statistically significant for most regions. These findings are in congruence with earlier studies suggesting the differences are mainly attributable to alterations in the elastic fiber network. This procedure provides a simple, quantitative assessment of elastic properties of the skin. Its application may help in future investigations of other connective tissue disorders.     

Mechanical properties of human forearm and vulvar skin

Using a newly developed suction device, the mechanical properties of forearm and vulvar skin were studied in 22 healthy women, 12 before and 10 after the menopause. The ratio between viscous deformation (Uv) and elastic deformation (Ue) and the biological elasticity, i.e. the ratio between immediate recovery (Ur) and total deformation (Uf), were both significantly lower in vulvar than in forearm skin. Ur/Uf decreased significantly with load in vulvar, but not in forearm skin, whereas Uv/Ue was not load-dependent in either site. Uv/Ue remained constant with age in both test sites, whereas Ur/Uf was significantly lower in post-menopausal women in both forearm and vulvar skin. In vulvar, but not in forearm skin, Uv/Ue was significantly correlated with body height which may be an indicator of mechanical connective tissue properties. Viscous deformation plays a lesser role and biological elasticity is decreased in vulvar compared to forearm skin. Despite differences in mechanical parameters at both sites, age-related changes seem to be similar.     

Evaluation of the inhibitory activity of topical indomethacin, betamethasone valerate and emollients on UVL-induced inflammation by means of non-invasive measurements of the skin elasticity

BACKGROUND/AIM: Topical indomethacin has been reported to inhibit ultraviolet light-induced erythema. The objective of this study was to verify this assertion and to compare indomethacin 10% ointment to beta-methasone valerate 0.1% ointment, water-in-oil emulsion and oil-in-water emulsion by means of non-invasive skin elasticity measurements. METHODS: Products were applied on the back skin 60 min and 5 min before and 5 min after UVL irradiation. Untreated test sites served as controls. Clinical evaluation, measurements of epidermal hydration (Corneometer) and mechanical properties of the skin (Cutometer) were made 1 h before and 24 h after exposure. RESULTS: Test areas treated with indomethacin 60 min and 5 min before irradiation showed the significantly lowest visual erythema scores and no significant changes in skin mechanical parameters. At all other test sites, a significant decrease in elasticity parameters (Ue, Ur, Ua/Uf, Ur/Uf) and an increase in viscoelasticity parameters (Uv, Uv/Ue) of the skin were observed. No significant changes of epidermal hydration were found at any of the test sites. CONCLUSION: The inhibitory action of topical indomethacin on UVL-induced inflammation is superior to beta-methasone valerate and emollients. Non-invasive measurement of skin elasticity could be used as a supplementary tool for objective evaluation and comparison of the photoprotective activity of different topical agents.     

Dermal fluid translocation is an important determinant of the diurnal variation in human skin thickness

BACKGROUND: Ultrasonography has been used as a non-invasive approach to measure skin thickness. To date there have been no studies on diurnal variations in skin thickness. OBJECTIVES: To evaluate diurnal variations in skin thickness and to compare these with corresponding echogenicity and skin elasticity. METHODS: Measurements by ultrasonography B-mode and by Cutometer SEM 575 were carried out in the morning and in the afternoon on 20 men and 20 women (mean age 30 years) on three areas of the face (forehead, corner of the eye and cheek), the forearm and the upper arm, and the flank, thigh and calf. RESULTS: From the morning to the afternoon, the skin thickness in both sexes significantly decreased on three areas of the face, the forearm and the upper arm, but significantly increased on the thigh and calf. In parallel, the echogenicity significantly increased from the morning to the afternoon on the three areas of the face, the forearm and the upper arm, but decreased significantly on the thigh and calf. Measurements of mechanical properties at four sites demonstrated that from the morning to the afternoon, the major parameters of skin elasticity Ue* and Uf* increased significantly in both sexes on two areas of the face and slightly on the forearm, but decreased significantly on the calf. CONCLUSIONS: The diurnal profiles of skin thickness and skin elasticity in the upper half of the body are the reverse of those in the lower half of the body. These findings suggest that shifts of dermal fluid from the face to the leg by gravity during the day cause the diurnal variation in skin thickness.     

Zur Katecholamin-Ausscheidung im Urin bei progressiver Sklerodermie (im indurativen Stadium)

Zusammenfassung Bei 19 Patienten mit progressiver Sklerodermie im indurativen Stadium wurden im Urin die Katecholamine Noradrenalin und Dopamin bestimmt. Hierbei ergaben sich im Vergleich mit einer Kontrollgruppe von 17 Personen keine statistisch signifikanten Unterschiede. Dieses negative Ergebnis erscheint trotzdem mitteilenswert, weil hieraus zu entnehmen ist, daß bei der progressiven Sklerodermie in den späteren skleratrophischen Stadien neurohormonal wirksame Impulse offenbar weitgehend zurücktreten und eine — obwohl initial vermutlich dergestalt induzierte — Verschiebung der Kollagenfraktionen, also sozusagen die Bindegewebskrankheit, im Vordergrund steht, was für therapeutische Überlegungen nicht ohne Bedeutung scheint.

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Urinary catecholamines in progressive systemic sclerosis (indurative phase)

Summary In 19 patients with progressive systemic sclerosis (indurative phase) urinary catecholamines (Noradrenaline and Dopamine) were determined with no statistical difference being found. This negative finding seems to be interesting, because it may be understood from our investigations that in the indurative phase of scleroderma neurohormonal impulses will slacken or disappear and the change of the collagen—fractions is gaining more pathogen etical importance.

     

Degenerative alterations of dermal collagen fiber bundles in photodamaged human skin and UV-irradiated hairless mouse skin: possible effect on decreasing skin mechanical properties and appearance of wrinkles

Dermal collagen fiber bundles (DCFB) are the major constructional element in the dermis. Although degenerative alterations of DCFB have been reported in chronologically aged skin, changes in photodamaged skin have not been fully investigated. We report ultrastructural alterations of DCFB, and their relation to skin elasticity using photodamaged human skin and UV-irradiated hairless mouse skin. The degree to which DCFB were intact and closely packed was evaluated and scored blindly. Exposed skin (outer forearm) exhibited marked ultrastructural degeneration. In UV-irradiated hairless mouse skin, the intact ultrastructural appearance of DCFB was gradually lost with increasing UV dosage; however, marked alterations in DCFB ultrastructure were absent in either human inner upper arm (unexposed) skin or nonirradiated age-matched control mouse skin. Skin mechanical properties were measured using a Cutometer SEM 474 suction extensometer, recording Ue* immediate deformation, Uv* viscous deformation, Uf* final deformation, and Ur* immediate contraction, all normalized for skin thickness. Uf*, Ue*, Uv*, and Ur/Uf were significantly decreased in exposed compared with unexposed skin. Significant positive correlations between degenerative alterations of DCFB and the decrease in Uf*, Ue*, and Uv* were seen. Changes of "% area of wrinkles" in UV-irradiated mouse skin was significantly correlated with degenerative changes of DCFB. Based on these results, we confirm observations made by others that chronic photodamage may have more severe effects on degeneration of DCFB than that of chronologic aging alone. Furthermore, degeneration of DCFB as detected ultrastructurally may, by its effect on skin elasticity, result in an increase in the appearance of wrinkles.     

A retrospective randomly selected cohort study of D-penicillamine treatment in rapidly progressive diffuse cutaneous systemic sclerosis of recent onset

BACKGROUND: Several uncontrolled studies in systemic sclerosis have shown that D-penicillamine may cause improvement in skin sclerosis, decrease the rate of new visceral organ involvement, and improve overall survival. OBJECTIVES: To undertake a single-centre retrospective randomly selected cohort study to examine the effects of D-penicillamine treatment on skin and visceral organ involvement in patients with rapidly progressive systemic sclerosis of recent onset. METHODS: Eighty-four patients with diffuse cutaneous systemic sclerosis who had received D-penicillamine within 24 months of clinically detectable onset of skin sclerosis were randomly selected from the systemic sclerosis cohort followed at the Scleroderma Center of Thomas Jefferson University. Employing a previously described severity scale, disease severity and skin involvement were compared from initiation of D-penicillamine to end of study and a correlated matched t-test was used to establish statistical significance. RESULTS: At a mean+/-SD duration of D-penicillamine therapy of 29.2+/-5.5 months and at a median dose of 750 mg per day statistically significant improvement in skin (P<0.01) and cardiac, pulmonary and renal involvement (P<0.05) was observed. At last follow-up, 17 (20%) patients were still receiving D-penicillamine, 25 (30%) had discontinued it owing to disease improvement, and 18 (21%) had discontinued it owing to side-effects. CONCLUSIONS: In a population of patients with diffuse cutaneous systemic sclerosis, with progressive disease of recent onset, D-penicillamine treatment at a median dose of 750 mg per day caused a statistically significant reduction in skin involvement and improvement of renal, cardiac and pulmonary involvement.     

Biomechanical assessment of photodamage

Background/Aims : Intrinsic aging and photoaging may present different biomechanical properties. Dorsal and volar forearm skin is differently exposed to UV-light. The object was to derive a cutaneous extrinsic aging score (SEAS) representative of UV aging, i.e. the global photoaging corrected for intrinsic aging.
Methods : The Cutometer SM 474 was used for the measurement of skin mechanical properties. 86 healthy Caucasian women were studied. Dorsal and volar forearm skin was measured.
Results : Age related changes consisting of an overall increase in skin extensibility (Uf) and viscoelastic ratio (Uv/Ue) with decreased biologic elasticity (BE) was observed. Differentials in extensibility (Uf) and viscoelastic ration (Uv/Ue) between the volar and the dorsal test sites increase with age.
Conclusions : Biomechanical parameters allow the evaluation of intrinsic aging in the concept of overall photoaging resulting from the combination of environmental damages superimposed to the intrinsic changes.     

SKIN COLLAGEN CONTENT AND THICKNESS IN SYSTEMIC SCLEROSIS

The thickness and collagen content of forearm skin were measured in 13 patients with systemic sclerosis, in 8 of whom the forearm skin was found to be clinically affected by the disease. No increase in skin thickness or its collagen content was found. The thickness and collagen content of the clinically affected forearm skin were usually decreased and collagen density was normal. It is concluded that the clinical impression of thickness and toughness is due to binding down of the skin to deeper structures. The similarity of atrophic morphoea and systemic sclerosis is discussed.     

Treatment of systemic sclerosis with extracorporeal photochemotherapy. Results of a multicenter trial.

BACKGROUND AND DESIGN--In a pilot study of extracorporeal photochemotherapy, two patients with systemic sclerosis who received this therapy experienced significant clinical improvement. These results prompted the development of a multicenter trial to examine the benefit of extracorporeal photochemotherapy in the treatment of systemic sclerosis. Seventy-nine patients with systemic sclerosis of recent onset (mean symptom duration, 1.83 years) and progressive skin involvement during the preceding 6 months entered a randomized, parallel-group, single-blinded clinical trial comparing extracorporeal photochemotherapy treatments given on 2 consecutive days monthly with treatment with D-penicillamine at a maximum dose of 750 mg/d. Blinded clinical examiners evaluated skin severity score (thickness), percent surface area involvement, oral aperture, and hand closure. Serial skin biopsies and pulmonary function studies were also performed. RESULTS--Following 6 months of treatment, significant improvement in skin severity score occurred in 21 (68%) of 31 patients receiving photochemotherapy and in eight (32%) of 25 receiving D-penicillamine treatment, while significant worsening occurred in three (10%) of 31 receiving photochemotherapy and in eight (32%) of 25 receiving penicillamine treatment, thus indicating a significantly higher response rate for individuals who received photochemotherapy (P = .02). At both the 6- and 10-month evaluation points, the mean skin severity score, mean percent skin involvement, and mean oral aperture measurements were significantly improved from baseline among those who received photochemotherapy. Mean right and left hand closure measurements had also improved significantly by 10 months of therapy. By comparison, among the patients treated with D-penicillamine, none of the parameters of cutaneous disease had improved significantly after 6 months of therapy, although for those individuals in whom treatment was continued, the mean skin severity score and mean percent skin involvement had improved by 10 months. Skin biopsy studies revealed a correlation between clinical improvement and decreased thickness of the dermal layer. Adverse effects of extracorporeal photochemotherapy were minimal and did not require discontinuation of treatment in any of the patients receiving this therapy; six patients permanently discontinued the use of D-penicillamine treatment due to adverse effects. CONCLUSIONS--For patients with systemic sclerosis of recent onset, extracorporeal photochemotherapy is a well-tolerated treatment that may partially reverse the process that results in cutaneous sclerosis.     

Quantitative measurement of desquamation and skin elasticity in diabetic patients

Background/aims: Diabetes mellitus is responsible for many cutaneous alterations. Xerosis and sclerotic change of the skin are the most common findings. Recently non- invasive computerized devices have been developed and used for determining the desquamation rate and measuring the mechanical properties of the skin. Using these devices, the necessity to characterize the conditions of the skin in the healthy as well as the diseased state is increasing. The aim of this study was to compare the elasticity and desquamation rate between the diabetic population and the normal population using non-invasive, objective methods.
Methods: Skin sites of 96 diabetics with normal appearance, were measured for skin elasticity and desquamation rate using the Cutometer^® and visual grading and D-Squame^®– image analysis method, respectively. The values of parameters were compared to values of 83 non-diabetics' results.
Results: There was a significant decrease in skin elasticity (expressed by Uv/Ue and Ur/Uf of the face) and in the value of fine flakes in the diabetics. Although insignificant, the SDI (Scale Density Index) calculated from objective automatic measurement was higher in the diabetics than the control group.
Conclusions: The elasticity of facial skin was decreased in patients with diabetes. Decrease of the fine flakes of the diabetes patients reflect that irritation and xerotic changes are aggravated in skins of diabetic patients. The results indicate the presence of skin elasticity alteration and desquamation with diabetes mellitus. Such non-invasive evaluations of the skin may be useful for evaluating changes in the skin that are associated with diabetes mellitus.     

In vivo study of skin mechanical properties in psoriasis vulgaris

The aim of this study was to investigate the mechanical properties of the skin in psoriatic plaques before and after treatment with dithranol and in clinically uninvolved psoriatic skin in comparison with the skin of healthy controls. In total, 82 psoriatic plaques in 19 in-patients and 51 age-matched control subjects were studied with a non-invasive suction device (Cutometer). The plaques were characterized by statistically significant lower skin distensibility and elasticity, and a higher viscoelastic to elastic ratio compared with adjacent apparently normal skin. Delayed distension and hysteresis measured using a 2-mm diameter probe were decreased, but were increased when measured by a 8-mm diameter probe. These differences can be explained by the increased skin thickness in psoriasis and by the different aspects of skin mechanics determined by the 2 measuring probes. After treatment, the mechanical parameters of psoriatic plaques approached the values of adjacent control skin. The uninvolved volar forearm skin in psoriatic patients (2-mm diameter probe) showed statistically significant lower values of skin distensibility and higher values of viscoelasticity parameters compared with the skin of healthy control subjects. This suggests that the normal-appearing psoriatic skin is not entirely normal. The non-invasive method applied can be used for objective and quantitative evaluation of the effect of therapy in patients with psoriasis.     

Ultraviolet A1 (340-400 nm) phototherapy for scleroderma in systemic sclerosis

BACKGROUND: The presence of an inflammatory infiltrate consisting of helper T cells and a dysregulated matrix metabolism leading to excessive deposition of collagen are two pathogenetic factors responsible for the developments of fibrosis and sclerosis in patients with systemic sclerosis. In previous studies, ultraviolet A1 (UVA1) radiation phototherapy was shown to deplete skin-infiltrating T cells through the induction of T-cell apoptosis and to up-regulate the expression of matrixmetalloproteinase-1 (collagenase-1) in dermal fibroblasts. OBJECTIVE: Our purpose was to determine whether UVA1 phototherapy is effective for systemic sclerosis. METHODS: Lesional skin on the forearms of patients with systemic sclerosis (diffuse type, n =3; limited type, n =1) was exposed to medium-dose UVA1 radiation (60 J/cm(2)) daily. RESULTS: In all patients studied, UVA1 phototherapy-treated skin lesions were markedly softened after 9 to 29 exposures. Clinical improvement was associated with an increase in (1) joint passive range of motion values (P <.05), (2) skin temperature (thermography, P <.05), and (3) cutaneous elasticity (cutaneous elastometry, P <.05). Histologic evaluation of skin specimens obtained before and after UVA1 phototherapy revealed loosening of collagen bundles and the appearance of small collagen fibers. CONCLUSION: These studies indicate that UVA1 phototherapy is effective for patients with systemic sclerosis.     

Measurement of Skin Elastic Properties with a New Suction Device (II): Systemic Sclerosis

We previously reported the skin elastic properties of normal subjects as measured by a newly developed suction device (6). In the present report, we examined the skin elastic properties of 62 patients with systemic sclerosis (SSc), clinically diagnosed as limited or diffuse type. We measured the skin elastic properties on the forearm and chest and investigated correlations with disease type and clinical skin score. Patients with the diffuse type SSc showed significantly lower values than those with the limited type SSc or normal subjects in distention and retraction ability at the chest and forearm. This suction device is clinically useful for the objective evaluation of skin elastic properties in diffuse systemic sclerosis.     

Biomechanical measurement of skin distensibility in scleredema of Buschke associated with multiple myeloma

We report a case of scleredema of Buschke associated with IgG kappa monoclonal hypergammaglobulinaemia. After myeloma polychemotherapy an improvement in skin involvement was observed and confirmed by means of noninvasive skin elasticity measurements. This suggests a relationship between the two diseases. The bioengineering method used can be useful for early detection and monitoring the skin involvement in patients with this disease association.     

Reversal effects of topical retinoic acid on the skin of kidney transplant recipients under systemic corticotherapy

The systemic long-term corticosteroid treatment administered to kidney graft recipients (KGR) within the framework of the required immunosuppressive therapy induces an atrophy of the skin, from the sixth month onwards. We studied the effect of topical all-trans retinoic acid (0.05%; Galderma Labs.) applied to the forearms of 27 KGR (14 men, 13 women) over a 6-month period. Twenty-four subjects completed the trial. The following results were obtained in the treated forearm versus the untreated forearm (excipient alone): clinically, an increase in skin thickness; by noninvasive techniques, an increase in skin thickness, skin elasticity, skin conductance, and TEWL, and a reduction in the size of the corneocytes. No change in stratum corneum lipid content was observed. A sex-related difference was noted in the response to treatment under our experimental conditions, the female patients responding better. A punch biopsy (4 mm) was performed on both forearms of four patients after the 6-month period. Histologic and ultrastructural examination revealed epidermal and dermal changes evoking increased cellular metabolism in the retinoic acid-treated forearms.     

Anticentromere antibody: an immunological marker of a subset of systemic sclerosis

Our clinical and immunological studies of 114 cases of systemic sclerosis, 54 of Raynaud's disease and 46 of other connective tissue diseases, centered on the diagnostic and prognostic significance of anticentromere antibodies (ACA). The ACA occurred in 21 of 84 patients with acrosclerosis, in four of 54 patients with Raynaud's disease but in none of 30 patients with diffuse scleroderma or transitional form, acrosclerosis-diffuse scleroderma, or 46 cases of other connective tissue diseases. The ACA-positive patients had no contracture or immobilization of the fingers, the indurations and/or indurative oedema were confined to fingers and usually no other types of ANA were detected. However, systemic involvement and the course of the disease were comparable in ACA-negative and ACA-positive acrosclerosis patients. The studies indicate that there is a subset of acrosclerosis with minimal indurations confined to the fingers, and ACA appears to be its serological marker. We propose to use the term CREST for this subset, which to date has not been exactly defined and is regarded by some authors as synonymous with acrosclerosis.     

Anti-Scl-70 antibodies in systemic scleroderma

We looked for anti-Scl-70 and anti-centromere antibodies in 109 patients (26 men and 83 women). Mean age was 43 +/- 15 years. Forty patients had systemic sclerosis according to ARA criteria. The extension of cutaneous involvement was defined by using Barnett and Coventry criteria: 12 patients were type I (sclerodactyly), 20 type II (acrosclerosis) and 8 type III (diffuse scleroderma). Among the 12 patients with type I, there were 8 cases of CREST syndrome defined as follows: presence of sclerodactyly, Raynaud's phenomenon and 2 of the 3 following criteria: oesophageal dysmotility, calcinosis, telangiectasia. Other organ involvement was recorded. Control patients had idiopathic Raynaud's phenomenon (n = 22), other connective tissue diseases (n = 20), and miscellaneous diseases (n = 28). Ninety-nine patients were prospectively included in this study. Patients' sera were stored at -20 degrees C. Ten previously stored sera obtained from patients with systemic sclerosis were also analyzed. Immunological tests were performed simultaneously and with no information on the diagnosis. When antinuclear antibodies were detected by indirect immunofluorescence, double immunodiffusion and immunoblotting were performed. Anti-Scl-70 antibodies were detected in systemic sclerosis only: 1 of 12 type I, 11 of 20 type II and 4 of 8 type III. One serum negative by immunodiffusion was positive using immunoblotting. We found that the specificity of anti-Scl-70 antibodies for systemic sclerosis was 100 p. 100 and their sensitivity 40 p. 100. There was a correlation between the presence of anti-Scl-70 antibodies and the presence of antinuclear antibodies (p less than 0.05) and the extent of cutaneous involvement (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

In vivo tretinoin-induced changes in skin mechanical properties

Topical tretinoin has been reported as having anti-aging effects on photodamaged skin. The purpose of this study was to evaluate tretinoin-induced changes in the mechanical properties of the skin of 18 patients (aged 39 +/- 8 years) after 4 months of treatment with topical 0.05% tretinoin on one forearm and a placebo base cream on the other. The biomechanical skin parameters investigated were elasticity, extensibility and hysteresis and data were normalized for skin thickness. A slight but non-significant increase of skin elasticity was detected in the tretinoin-treated sites using low-stressing forces (1.2 X 10(4) Nm-2) and at higher loads (3.8 X 10(4) Nm-2), the increase in skin elasticity was significant (P less than 0.01). This improved skin elasticity was dependent on the increased collagen resulting from topical tretinoin and the replacement of elastotic material. However, topical tretinoin treatment did not improve the responses mediated by elastic fibres.