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A modified photometric technique for measuring sebum excretion rate.

Accurate measurement of sebum excretion is necessary to evaluate drugs such as anti-androgen and the new retinoic acid derivatives. Existing techniques are good, but some are inaccurate at high levels of sebum and are time-consuming for technicians. We have therefore, re-examined sebum excretion methodology and have developed a modified photometric technique. This technique, which utilizes a robust, portable machine gives data which are accurate at all levels of sebum production and reduces the technician time of analysis without loss of accuracy or reproducibility.

Humans↗

Measurement of sebum output using a lipid absorbent tape.

A sebum absorbent tape is introduced as a reproducible and convenient method for estimation of sebaceous gland output. We have tested the reproducibility of this method by serial measurements of sebum excretion rates (SER) of 10 individuals over a 6-week period, and in addition we have correlated this method with the conventional hexane extraction technique. The sebum absorbent tapes gave consistent values for the SERs, and within subjects variation over the 6-week period was statistically nonsignificant. A coefficient of variation for the tapes was calculated as 16.25 +/- 6.78% based on these serial measurements. Furthermore, the amount of total lipid collected using this technique (n = 16) correlated well with the hexane extraction technique, r = 0.89. Free fatty acids (r = 0.87), triglycerides (r = 0.92), wax and cholesterol esters (r = 0.83), and squalene (r = 0.88) also showed a good correlation. Cholesterol occasionally suffered from incomplete separation on thin-layer chromatograms; however, a sample cleanup procedure was developed for tape extracts that removed interfering materials and allowed complete separation of all sebum components.

Absorption↗

Influence of oral metronidazole on the endocrine milieu and sebum excretion rate.

As part of a study of the mechanism of metronidazole's efficacy in the treatment of acne and rosacea, its effects on the endocrine milieu and sebum excretion rate were assessed. Thirteen healthy males received oral metronidazole treatment (500 mg/day) for 4 weeks. Serum sex hormone levels were determined in all 13 subjects and the sebum excretion rate was determined in seven of them, before and after treatment. We measured serum levels of estrone (E1), estradiol (E2), total testosterone (T), free testosterone (FT), dihydrotestosterone (DHT), dehydroepiandrosterone sulfate (DHEA-S), and sex hormone-binding globulin (SHBG). There were no significant changes in E1, T, FT, DHT, or SHBG levels, but E2 and DHEA-S levels decreased significantly after treatment. In all seven subjects in whom the sebum excretion rates were determined, the amount of facial skin surface lipids decreased significantly after treatment. These results suggest that metronidazole exerts its clinical effects through suppressing the sebum excretion by a mechanism other than anti-androgenic action.

Administration, Oral↗

A direct gravimetric technique for measuring sebum excretion rate.

The standard gravimetric method for measuring sebum excretion rates involves ether extraction of the collected sebum. We have evaluated a more direct method in which the collecting papers were pre- and post-weighed in glass beakers under conditions of stable temperature and humidity. Weights were adjusted allowing for control weight gain or loss, due mainly to day to day changes in weight room humidity. The direct method compared favourably with the ether extraction method in determining: (1) sebum collected from 43 subjects (r = 0.991, P less than 0.001), (2) left versus right forehead comparisons in 19 subjects (direct method: r = 0.966, P less than 0.001; ether extraction method: (r = 0.963, P less than 0.001), and (3) recovery of sebum from 32 premeasured standards (r = 0.997, P less than 0.001). The findings demonstrate the accuracy of the direct gravimetric procedure which is also simpler, safer and less expensive than methods currently in use.

Forehead↗

Genetic control of sebum excretion and acne--a twin study.

Sebum excretion and acne grades were measured in 20 pairs each of identical and non-identical like-sex twins. The identical twins had virtually identical rates of sebum excretion (P greater than 0.05), but they had a significantly different degree of acne severity (P less than 0.01). The non-identical twins had significantly different sebum excretion rates (P less than 0.01) and acne grades (P less than 0.01). These findings suggest that sebum excretion is under genetic control and the development of clinical lesions is modified by environmental factors.

Acne Vulgaris↗

Physiology of the vellus hair follicle: hair growth and sebum excretion.

The growth of vellus hair and the secretion of sebum from vellus hair follicles were measured on the forehead, cheek, chest, shoulder and back of healthy men and women aged 15-30 years. Hair growth was assessed by computerized image-analysis of photographs and sebum excretion by the use of Sebutape followed by image analysis. The density of vellus hairs and the percentage of growing hairs were higher on the face than on the thorax (439 hairs/cm2 with 49% growing hairs on the forehead compared with 85 hairs/cm2 with 31.5% growing hairs on the back). The rate of growth ranged from 0.03 mm/day on the forehead to 0.13 mm/day on the back. The maximum length of vellus hair significantly decreased with age; otherwise hair growth was not affected by age or sex. Some variations in hair growth and sebum secretion were observed over a period of 3 months, but no consistent rhythms were detected. There was no obvious link between vellus hair growth and sebum excretion.

Adolescent↗

Sebum secretion in idiopathic Parkinson's disease: effect of anticholinergic and dopaminergic drugs.

Sebum secretion was measured on the foreheads of 47 unmedicated patients with idiopathic Parkinson's disease, aged 50-81 years and 80 healthy, matched volunteers. Sebum secretion was significantly higher in men patients aged 50-59 years than in controls; no such difference was observed in women of the same age. There was also no difference between patients and volunteers of either gender older than 60 years of age. The effects of either biperiden, L-Dopa + benserazide (a decarboxylase inhibitor) or bromocriptine treatments on sebum secretion and on 5 parkinsonian signs were evaluated over 127 days. There was a significant reduction of all measures during the treatment with the dopaminergic drugs. The only observable effect with biperiden was reduction of tremor. It is discussed whether the sebum suppressive effect of the dopaminergic drugs may be explained through their central effects.

Aged↗

Effects of sex steroid deprivation/administration on hair growth and skin sebum production in transsexual males and females.

To investigate androgen effects on the skin pilosebaceous unit, we studied 21 male-to-female transsexuals and 17 female-to-male transsexuals receiving cross-sex hormones. At baseline and after 4, 8, and 12 months, hair growth was evaluated by the Ferriman-Gallwey score; acne by the Leeds classification; hair growth rate, density, and shaft diameter by image analysis; and sebum production by Sebutape. In males, estrogens and antiandrogens reduced plasma testosterone to below 1.0 nmol/L. Though all parameters of hair growth and sebum production declined, facial hair growth continued. After 4 months, the decrease in shaft diameter had reached its maximum and seemed inversely associated with changes in hair growth length and density. In females, testosterone increased hair growth rate and sebum production. After 12 months, hairs on the cheek and abdomen had not yet reached diameters found in males. 5alpha-Androstane-3alpha,17beta-diol glucuronide levels were only weakly associated with hair growth and sebum production. In conclusion, administration of estrogens and antiandrogens affects length and diameter of hairs at different rates. In the virtual absence of androgens, hair growth continues but at a slower rate. In women, after 12 months of androgen administration, hair diameters have not reached values of adult men.

Acne Vulgaris↗

Sebum and water content in the skin of aged immobilized patients.

In the present study we investigated the sebum content and hydration of the skin in aged immobilized patients. Healthy aged as well as young and aged immobilized patients were evaluated by photometry, using a sebum tester and capacitance meter to detect sebum and hydration, respectively, in various skin areas. Sebum content was significantly higher in the young groups as compared to the aged ones, including those of the immobilized patients. Similar values of water content were observed in the healthy young and aged volunteers. However, surprisingly, a significantly marked decrease was detected in each tested area of the immobilized patients. We may assume that a cascade of events caused by the immobilization status of the patients leads to a significant decrease in water content within the dermis.

Adult↗

Arotinoid Ro 13-6298 and etretin: two new retinoids inferior to isotretinoin in sebum suppression and acne treatment.

Thirty patients have been treated with either etretin, the main derivative of etretinate, or arotinoid Ro 13-6298, a polyaromatic retinoid, or isotretinoin. Sebum production was measured before and during the treatments. While no change was observed in the patients treated with etretin, a reduction of 33% of the sebum excretion rate was observed for those treated with arotinoid Ro 13-6298 but only after long treatment periods of 20 to 30 weeks. The sebum excretion rate decreased by 92% in the patients treated with isotretinoin. Four patients suffering from severe nodulocystic acne were treated with arotinoid Ro 13-6298 for 2-5 months without improvement. Substantial improvement, however, resulted after a subsequent treatment with isotretinoin; sebum production decreased markedly as well. This study suggests that neither etretin nor arotinoid Ro 13-6298 will replace isotretinoin in the treatment of severe nodulocystic acne.

Acitretin↗

Changes in sebum secretion and the sebaceous gland.

New data have shown that sebum secretion is highest in young adults and then declines steadily throughout life in both men and women. This parallels the decline in androgen levels, but this cannot be the sole factor because there is so much overlap in sebaceous gland activity between men and women. The increased occurrence of dry skin in the elderly has been shown to be unrelated to the sebum secretion rate. This is not unexpected, as children, with even less sebum, rarely have this problem. Seborrheic dermatitis, which is also much more common in the elderly, is also unrelated to sebum secretion rate.

Aging↗

Changes in sebum secretion and the sebaceous gland.

New data have shown that sebum secretion is highest in young adults and then declines steadily throughout life in both men and women. This parallels the decline in androgen levels, but this cannot be the sole factor because there is so much overlap in sebaceous gland activity between men and women. The increased occurrence of dry skin in the elderly has been shown to be unrelated to the sebum secretion rate. This is not unexpected, as children, with even less sebum, rarely have this problem. Seborrheic dermatitis, which is also much more common in the elderly, is also unrelated to sebum secretion rate.

Adolescent↗

Studies on the critical period of neonatal life for the differentiation of sebum secretion in rats.

Sprague-Dawley rats were castrated at the age of 1, 3, 5, 10 or 21 days. A control group of male and female rats were also included for comparison. The secretion rate of sebum was assessed from the amount of skin-surface lipids that could be extracted by acetone and which had been produced during 2 days. Sebum production increased with age, particularly in male rats. Castration of male rats at the age of 1, 3, 5, or 10 days showed no differences from female rats in sebum secretion when measured at the age of 80 days. On the other hand, male rats that had been castrated at the age of 21 days secreted significantly more sebum than female rats.

Animals↗

A prospective study of the effect of isotretinoin on the follicular reservoir and sustainable sebum excretion rate in patients with acne.

BACKGROUND AND DESIGN: A prospective study of 30 patients with moderate to severe acne was performed. The follicular reservoir and sustainable sebum excretion rates were measured before and after a 4-month course of isotretinoin at a dose of 1 mg/kg per day. RESULTS: The follicular reservoir and sustainable sebum excretion rates were profoundly reduced at the end of the course of isotretinoin (79% and 83%, respectively) and remained significantly suppressed at 1 year following therapy (43% and 36%, respectively). Those patients who relapsed clinically at 1 year after treatment had a significantly higher follicular reservoir rate. CONCLUSIONS: These data support the concept that up to 1 year after therapy, there is a reduction in the sebum secretion rate accompanying the remission of acne. This suppressed sebum secretion may modulate the microenvironment of the pilosebaceous canal through an effect on the follicular reservoir.

Acne Vulgaris↗

Degreasing method for the seborrheic areas with respect to regaining sebum excretion rate to casual level.

BACKGROUND/AIMS: Sebum excreted from the seborrheic glands keeps the skin surface subtle and moist. Before determining the activity of seborrheic glands, the skin surface must be degreased to remove contamination but without provoking sebum excretion. The purpose of this study was to set up a standardised degreasing procedure for various seborrheic areas in different skin types. The method will take day-to-day variations into account with respect to the kinetics of refatting. METHODS: The Sebumeter(R) from Courage+Khazaka is used to quantify the sebum excretion. Day-to-day variations were measured on the forehead in groups of 12 volunteers on 2 consecutive days. The degreasing procedure was investigated by individual cleaning with alcohol compared to washing with a mild detergent followed by wipes with alcohol on the forehead. The degree of refatting was monitored until 3 h after defatting on seborrheic areas: the forehead, cheek, nose, chin and upper back. RESULTS: There was no statistical significant difference in the variation from day to day (P<0.05), although a change in the individual skin types was observed. An individual difference in the number of alcoholic wipes needed to degrease the forehead was seen. Washing followed by several repetitions of alcoholic wipes was not sufficient for the forehead, chin and nose (P>0.05). For the cheek and upper back, it was sufficient to wash with soap (P<0.05). The time from degreasing the skin until the sebum output reached the casual level was 2 h (P>0.05). The area under the curve (AUC) indicates that individual skin types return to casual level after defatting. CONCLUSION: There was no statistically significant day-to-day variation using the Sebumeter(R). We ended up with different degreasing procedures in different seborrheic areas. Washing gently with a detergent solution and then performing three wipes with alcohol was optimal for degreasing the forehead, nose and chin. For the cheek and upper back, it was sufficient to use a mild soap. Casual level was reached after 2 h in all seborrheic areas, irrespective of level of oiliness.

Journal Article↗

Skin aging. Effect on transepidermal water loss, stratum corneum hydration, skin surface pH, and casual sebum content.

This study investigates the effect of cutaneous aging on transepidermal water loss, stratum corneum hydration (capacitance), skin surface pH, and causal sebum content. Because the physiologic condition of skin varies considerably with anatomic region and skin aging might demonstrate regional variability, all factors were studied on 11 anatomic locations in 14 young adult (seven female and seven male subjects; 26.7 +/- 2.8 years [mean +/- SD]) and 15 aged human volunteers (seven female and seven male subjects; 70.5 +/- 13.8 years). Significant anatomic variability was noted for all factors in both age groups. However, no significant differences between the two groups were noted for sebum, capacitance, and pH on most anatomic regions. Transepidermal water loss, however, was significantly lower in the aged population on all anatomic regions tested, except for the postauricular region and the palm. Comparing male and female volunteers, none of the four factors showed significant differences. Of all measured factors, only transepidermal water loss showed significant age-related differences on most anatomic regions studied. The additionally observed differences between the age groups on the ankle for pH and sebum might be related to the stasis frequently observed on the lower limbs in aged individuals.

Adult↗

Effect of an orally administered arotinoid, Ro 15-0778, on sebum production in man.

1,2,3,4-Tetrahydro-1,1,4,4-tetramethyl-y-[(E)-alpha-methylstyryl]- naphthalene (Ro 15-0778), a potent inhibitor of sebaceous gland activity in several animal models has been administered to male volunteers in dosages of 1, 2, 3, and 6 mg/kg/day and 2 g/day for 8 weeks. Sebum production was measured before treatment and after 4 and 8 weeks of therapy. At the dosage levels of 1, 2, 3, and 6 mg/kg/day there was no decrease in sebum secretion. With the dosage of 2 g/day, a significant decrease in sebum secretion was seen after 8 weeks of treatment with Ro 15-0778.

Acne Vulgaris↗

Effect of 13-cis-retinoic acid on sebum production and Propionibacterium acnes in severe nodulocystic acne.

Ten patients treated with 13-cis-retinoic acid demonstrated a 70% reduction in sebum excretion on the forehead and cheek. An average reduction of 66% occurred in the 1st month, slowly increased to 70% by the 3rd month, and then remained constant for the final 2 months of therapy. Concomitant with this sebum excretion reduction was a fall in the number of Propionibacterium acnes recovered from both sites. Pretreatment values of 10(4) P. acnes per square centimeter (cm2) fell to 10(3) per cm2 after 1 month and 10(2) after 9 months of therapy. P. acnes was not recovered from six of the ten subjects in the following 3 months and only at levels of 10(2) per cm2 in three subjects. One subject's P. acnes level was reduced to only 10(4) per cm2. Following discontinuation of therapy, sebum levels and P. acnes counts showed a trend to recover to pretreatment levels within 2 months.

Acne Vulgaris↗