Biomedical subjects

D Thiboutot

Publications and source records attributed to D Thiboutot.

17 recordsLinked to original sources

PubMed2004

Inhibition of papilloma progression by antisense oligonucleotides targeted to HPV11 E6/E7 RNA.

Human papillomaviruses (HPVs) are recognized as important human pathogens, causing a spectrum of hyperproliferative lesions from benign warts to cervical dysplasias/carcinomas. HPV-associated lesions require continued production of the oncogenic E6/E7 proteins, which are encoded by either bicistronic or overlapping mRNAs. Here we targeted the E6/E7 mRNA of HPV11, a type implicated in causation of genital warts, using molecular reagents. Accessible sites in the HPV11(E6/E7) RNA were identified using library selection protocols, and nucleic acids (DNAzymes, antisense oligonucleotides) targeted to these sites were constructed, and tested in cell culture and on human foreskin grafts. While DNAzymes were at least equally effective in cell culture, antisense oligonucleotides targeted to the region surrounding one of the library-selected sites (ASO(407)) proved most effective in blocking progression of HPV11-induced papillomas in human foreskin grafts on immunodeficient mice. In total, 11 papillomas were treated with ASO(407). Of these, four of seven small papillomas treated with ASO(407) showed loss of detectable virus by in situ hybridization (ISH), and in all four of these, papillomas were no longer evident grossly or histologically after treatment. When larger papillomas were treated, one of four showed loss of virus by ISH, associated with a minor decrease in papilloma size. Considering all 11 papillomas treated with ASO(407), loss of viral staining by ISH was significantly different from that observed in controls (P<0.016), as was true for the seven small treated papillomas (P<0.012). DNAzymes targeted to the same site (or other library selected sites) did not produce statistically significant differences in ISH staining (P<0.15). Our results with ASO(407) appear to represent the first specific molecular therapy against a bona fide HPV infection, and provide a rational proof-of-principle strategy for development of molecular therapeutics targeting other HPV-associated lesions.

Animals↗

PubMed2001

A randomized, controlled trial of a low-dose contraceptive containing 20 microg of ethinyl estradiol and 100 microg of levonorgestrel for acne treatment.

OBJECTIVE: To evaluate the efficacy of a low-dose oral contraceptive (OC) containing 100 microg of levonorgestrel (LNG) and 20 microg of ethinyl estradiol (EE) compared with placebo for the treatment of moderate acne. DESIGN: Multicenter, randomized, double-blind, placebo-controlled clinical trial. SETTING: Outpatient dermatology clinics. PATIENT(S): Women (> or =14 years old; n = 350) with normal menstrual cycles and moderate acne were randomized to receive LNG/EE or placebo for six cycles. INTERVENTION(S): Twenty microg of EE and 100 microg of LNG. MAIN OUTCOME MEASURE(S): Acne lesion counts and clinician global assessment were performed at baseline and at each cycle. Patient self-assessment was carried out at baseline and at cycles 4 and 6; blood pressure and weight were measured at baseline and at cycles 1, 3, and 6. RESULT(S): Inflammatory, noninflammatory, and total lesion counts at cycle 6 with LNG/EE were significantly lower compared to placebo. Patients in the LNG/EE group also had significantly better clinician global and patient self-assessment scores than those in the placebo group at cycle. Changes in weight from baseline were similar between patients in the LNG/EE and placebo groups at all measured time points. CONCLUSION(S): This double-blind, placebo-controlled study demonstrates that a low-dose OC containing 20 microg of EE and 100 microg of LNG is an effective and safe treatment for moderate acne.

Acne Vulgaris↗

PubMed2001

Health-related quality of life among patients with facial acne -- assessment of a new acne-specific questionnaire.

The psychosocial effects of facial acne are well accepted but until recently few validated instruments existed which were suitable for use in clinical trials. The aim of this study was to assess measurement characteristics (reproducibility, correlation with acne severity, and sensitivity to detect change after acne therapy) of a new acne-specific quality of life instrument, the Acne-QoL. We found that the Acne-QoL is reliable, valid and able to distinguish differences across severity groups and improvement over 16 weeks of standard therapy. The use of the Acne-QoL should aid physicians in understanding the impact of facial acne on young adults, and may be useful in assessing therapeutic effects in acne clinical trials.

Acne Vulgaris↗

PubMed2001

Acne. Introduction.

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Acne Vulgaris↗

PubMed2001

Hormones and acne: pathophysiology, clinical evaluation, and therapies.

Hormonal aspects of acne are of particular interest in treating adult women. A review of the role of hormones in the pathogenesis of acne, guidelines for the workup of a suspected endocrine disorder, and an overview of the use of hormonal therapy in women with endocrine problems and in normal women is presented.

Acne Vulgaris↗

PubMed2001

Randomized controlled trial of the tolerability, safety, and efficacy of adapalene gel 0.1% and tretinoin microsphere gel 0.1% for the treatment of acne vulgaris.

A prior meta-analysis of 5 randomized controlled trials indicates that adapalene gel 0.1% is as effective as tretinoin gel 0.025% against acne and has greater tolerability. To determine the tolerability and efficacy of adapalene gel 0.1% versus tretinoin microsphere gel 0.1% in 168 patients with acne vulgaris, we conducted a 12-week, multicenter, randomized, controlled, investigator-masked, parallel-group design study. Efficacy variables included noninflammatory, inflammatory, and total lesion counts; global grade; and global assessment of improvement in acne severity. Skin tolerability variables included erythema, desquamation (scaling), dryness, pruritus, and stinging/burning. Our results showed that the efficacy of adapalene gel 0.1% was comparable to that of tretinoin microsphere gel, and both treatments had similar onset of action. Cutaneous tolerability was noted in both groups, with scores significantly better with adapalene gel 0.1% than with tretinoin microsphere gel 0.1%, and significantly fewer treatment-related adverse events were reported with adapalene gel 0.1%.

Acne Vulgaris↗

PubMed2000

Immunolocalization of 5alpha-reductase isozymes in acne lesions and normal skin.

BACKGROUND: Dihydrotestosterone mediates androgen-dependent diseases, such as acne, hirsutism, and androgenetic alopecia. This hormone is produced from testosterone by the 5alpha-reductase enzyme. There are 2 isozymes of 5alpha-reductase (types 1 and 2) that differ in their localization within the body and even within the skin. Activity of the type 1 isozyme predominates in sebaceous glands, where it may be involved in regulation of sebum production. Since specific inhibition of 5alpha-reductase type 1 may represent a novel therapeutic approach to acne, it is important to define the localization of these isozymes in normal sebaceous follicles and acne lesions. OBSERVATIONS: Skin biopsy specimens were obtained from the backs of 11 subjects: 8 with acne and 3 without acne. Sections of normal follicles, open comedones, closed comedones, and inflammatory lesions were incubated with antibodies to types 1 and 2 5alpha-reductase. In all samples, the type 1 antibody localized specifically to sebaceous glands, and the type 2 antibody localized to the companion layer of the hair follicle (the innermost layer of the outer root sheath) and granular layer of the epidermis. Localization of the type 2 isozyme was also noted within the walls of open and closed comedones and in endothelial cells from sections of inflammatory lesions. CONCLUSIONS: The immunolocalization of 5alpha-reductase isozymes in normal sebaceous follicles and acne follicles is similar to the pattern described in terminal hair follicles and corresponds with the findings of biochemical studies that have demonstrated predominance of type 1 activity in sebaceous glands. The function of type 2 5alpha-reductase in comedones or endothelial cells in inflammatory lesions is unknown.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗

PubMed2000

New treatments and therapeutic strategies for acne.

Successful management of acne requires careful patient evaluation followed by consideration of several patient and medication factors when selecting a particular therapeutic regimen. Within the last few years, several new agents for the treatment of acne have become available that afford greater flexibility in the treatment of this prevalent dermatologic disorder. These include adapalene, tazarotene, 2 new topical tretinoin formulations, azelaic acid, a new sodium sulfacetamide formulation, and an oral contraceptive recently approved by the Food and Drug Administration for the treatment of acne. After a brief overview of the pathophysiology of acne and existing therapies, this review evaluates the new antiacne agents and how they can be integrated into a successful treatment strategy that takes into account acne severity and predominant lesion type as well as age, skin type, lifestyle, motivation, and the presence of coexisting conditions.

Acne Vulgaris↗

PubMed2000

The melanocortin 5 receptor is expressed in human sebaceous glands and rat preputial cells.

Melanocortins regulate pigmentation, adrenal hormone secretion, immune functions, lipid metabolism, and feeding behaviors in rodents. These peptides include adrenocorticotrophic hormone, melanocyte stimulating hormone, beta-lipotrophin, and the endorphins. Lipid metabolism in sebaceous glands and preputial glands of rodents is regulated by alpha-melanocyte stimulating hormone, the major agonist for melanocortin receptors. Five melanocortin receptor subtypes have been identified that differ in their tissue localization and affinities for melanocortin ligands. Targeted disruption of the melanocortin 5 receptor in transgenic mice results in widespread dysfunction of exocrine glands, including a marked decrease in sebum production. A role for melanocortins in the modulation of human sebum production has not been established. The goal of this study is to determine which melanocortin receptors are expressed in human sebaceous glands. Messenger RNA was isolated from human sebaceous glands and the reverse transcriptase polymerase chain reaction was performed using primers specific for each of the melanocortin receptor subtypes. Transcripts were detected for the melanocortin 5 receptor. A polyclonal chicken antihuman antibody to the melanocortin 5 receptor localized to sebaceous glands, eccrine glands, hair follicles, and epidermis in human skin, rat skin, cultured human sebocytes, and rat preputial cells. Presence of the melanocortin 5 receptor protein in human sebaceous glands and rat preputial glands was further verified by Western blotting. These data support further investigation of the role of melanocortins in the regulation of human sebum production and support the use of the rat preputial system as an experimental model in sebaceous gland physiology.

Animals↗

PubMed1999

Propecia dosages.

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5-alpha Reductase Inhibitors↗

PubMed1999

Androgen metabolism in sebaceous glands from subjects with and without acne.

OBJECTIVE: To determine if there are differences in the activity of 17beta-hydroxysteroid dehydrogenase and 5alpha-reductase (responsible for the production of testosterone and dihydrotestosterone, respectively) in sebaceous glands obtained from men and women with and without acne. DESIGN: Single-center examination of androgen levels and sebaceous gland enzyme activity in a cohort of volunteers. SETTING: Academic referral center. PATIENTS: Thirty-four subjects, consisting of 8 women with acne, 10 women without acne, 8 men with acne, and 8 men without acne. INTERVENTIONS: Single visit for blood sampling and 2 biopsies of forehead skin. MAIN OUTCOME MEASURES: Serum levels of androgens were determined and compared with the activity of 5alpha-reductase and 17beta-hydroxysteroid dehydrogenase in sebaceous glands microdissected from skin samples. RESULTS: No significant differences in the activity of 5alpha-reductase or 17beta-hydroxysteroid dehydrogenase in sebaceous glands according to the presence of acne were noted in either men or women. The activity of 5alpha-reductase and 17beta-hydroxysteroid dehydrogenase was significantly greater in sebaceous glands from men (n = 16) than women (n = 17). The oxidative activity of 17beta-hydroxysteroid dehydrogenase was 2-fold higher in men than women. Serum levels of dehydroepiandrosterone sulfate, androstenedione, testosterone, and dihydrotestosterone were significantly higher in women with acne than in women without acne. No differences in serum androgen levels were noted in men on the basis of the presence of acne. CONCLUSIONS: Higher serum androgen levels are associated with the presence of acne in women. A role for locally produced androgens in this process, however, cannot be excluded.

17-Hydroxysteroid Dehydrogenases↗

PubMed1999

Finasteride in the treatment of men with frontal male pattern hair loss.

BACKGROUND: Finasteride, a specific inhibitor of type II 5alpha-reductase, decreases serum and scalp dihydrotestosterone and has been shown to be effective in men with vertex male pattern hair loss. OBJECTIVE: This study evaluated the efficacy of finasteride 1 mg/day in men with frontal (anterior/mid) scalp hair thinning. METHODS: This was a 1-year, double-blind, placebo-controlled study followed by a 1-year open extension. Efficacy was assessed by hair counts (1 cm2 circular area), patient and investigator assessments, and global photographic review. RESULTS: There was a significant increase in hair count in the frontal scalp of finasteride-treated patients (P < .001), as well as significant improvements in patient, investigator, and global photographic assessments. Efficacy was maintained or improved throughout the second year of the study. Finasteride was generally well tolerated. CONCLUSION: In men with hair loss in the anterior/mid area of the scalp, finasteride 1 mg/day slowed hair loss and increased hair growth.

5-alpha Reductase Inhibitors↗

PubMed1999

Immunohistochemical localization of types 1 and 2 5alpha-reductase in human scalp.

The predominant form of 5alpha-reductase (5aR) in human scalp is 5aR1. None the less, clinical studies have shown that finasteride, a selective inhibitor of 5aR2, decreases scalp dihydrotestosterone and promotes hair growth in men with androgenetic alopecia. Immunolocalization studies were thus carried out to examine 5aR isozyme distribution within scalp and, in particular, to determine whether 5aR2 might be associated with hair follicles. 5aR2 was localized using both a rabbit polyclonal and a mouse monoclonal antibody. 5aR1 was detected with a mouse monoclonal antibody. The specificity of these reagents was demonstrated both by immunofluorescence and Western blot analyses of COS cells overexpressing human 5aR1 or 5aR2. When cryosections of scalp from men with androgenetic alopecia were stained with antibody against 5aR2, using immunoperoxidase avidin-biotin complex methodology, immunostaining was observed in the inner layer of the outer root sheath and, in more proximal regions of the follicle, in the inner root sheath. Staining was also prominent in the infundibular region of the follicle, with less intense staining extending throughout the granular layer of the epidermis. Some staining was also seen in sebaceous ducts. Similar results were obtained with both the polyclonal and monoclonal 5aR2 antibodies. In contrast, in scalp cryosections stained with antibody to 5aR1, no immunostaining was observed within hair follicles. Intense staining for the type 1 isozyme was, however, detected within sebaceous glands. Our immunolocalization data suggest that the results seen in clinical trials of men with male pattern hair loss treated with finasteride may be due, at least in part, to local inhibition of 5aR2 within the hair follicle.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗

PubMed1998

Oxidative activity of the type 2 isozyme of 17beta-hydroxysteroid dehydrogenase (17beta-HSD) predominates in human sebaceous glands.

Sebum production is regulated by the opposing effects of androgens and estrogens. The intracrine activity of steroid metabolizing enzymes is important in regulating sebum production because these enzymes can convert weak steroids from the serum into potent androgens and estrogens within the sebaceous gland (SG). 17Beta-hydroxysteroid dehydrogenase (17beta-HSD) interconverts weak and potent sex steroids via redox reactions. In this regard, it may function as a gatekeeping enzyme regulating the hormonal milieu of the SG. Six isozymes of 17beta-HSD have been identified that differ in their substrate preference and their preference to produce weak or potent sex steroids via oxidation or reduction, respectively. The goals of this study are: (i) to identify which isozyme (s) of 17beta-HSD is active in SG; (ii) to determine if its activity differs in facial skin compared with nonacne-prone skin that may account for the regional differences in sebum production; (iii) to compare the activity of 17beta-HSD in intact glands and in SG homogenates; and (iv) to determine if 13-cis retinoic acid inhibits 17beta-HSD activity. Human SG were assayed for 17beta-HSD activity using estrogens, androgens, and progestins as substrates. Oxidative activity of the type 2 isozyme predominated in all samples tested. Although transcripts for the types 1, 2, 3, and 4 isozymes were detected using reverse transcriptase-polymerase chain reaction, only mRNA for the predominant type 2 isozyme and the type 4 isozyme were detected in northern analysis. Greater reductive activity of 17beta-HSD was noted in SG from facial areas compared with nonacne-prone areas, suggesting an increased net production of potent androgens in facial areas. Oxidation was more predominant over reduction in intact SG compared with homogenized SG, thus supporting the hypothesis that 17beta-HSD protects against the effects of potent androgens in vivo. Activity of the type 2 17beta-HSD was not inhibited by 13-cis retinoic acid. In conclusion, SG possess the cellular machinery needed to transcribe the genes for the type 1-4 isozymes of 17beta-HSD. At the protein level, however, oxidative activity of the type 2 isozyme predominates, suggesting that 17beta-HSD isozyme activity may be translationally regulated.

17-Hydroxysteroid Dehydrogenases↗

PubMed1998

Activity of 5-alpha-reductase and 17-beta-hydroxysteroid dehydrogenase in the infrainfundibulum of subjects with and without acne vulgaris.

Linoleic acid deficiency, interleukin 1, retinoids and androgens have been implicated as causative factors in the follicular hyperkeratinization seen in acne. The goal of this study was to test the hypothesis that more androgens are produced in follicles of acne subjects compared to subjects without acne. Thirty-four subjects (males and females with and without acne) were studied. The activity of 5 alpha-reductase (5 alpha-R) and 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) was determined in keratinocytes cultured from the infrainfundibulum and epidermis. Mean enzyme activities were slightly higher in the acne groups compared to the groups without acne, but differences were not statistically significant, perhaps due to limitations of this in vitro model. The activity of both 5 alpha-R and 17 beta-HSD was significantly greater in infrainfundibular keratinocytes compared to epidermal keratinocytes in all subject groups. 17 beta-HSD activity was 2.5- to 7-fold greater than the activity of 5 alpha-R in infrainfundibular keratinocytes. The regulation of 17 beta-HSD by endogenous factors may be important in determining the directional activity of 17 beta-HSD and hence the local concentration of testosterone within the infrainfundibulum. Additional studies of the effects of androgens on follicular keratinization are needed.

17-Hydroxysteroid Dehydrogenases↗

PubMed1996

Evaluating health-related quality of life in patients with facial acne: development of a self-administered questionnaire for clinical trials.

Although psychosocial aspects of skin diseases are well known, disease-specific questionnaires validated for use in clinical trials are not available to assess the impact of facial acne on health-related quality of life or to evaluate therapeutic change. Development of such an instrument was undertaken and included item generation, reduction and pilot-testing phases. By interviewing acne subjects and dermatologists and literature review, 168 possible items were identified. Next, 165 acne subjects identified which items affected them and rated importance on a 5-point scale. Reduction to a brief questionnaire was performed by evaluating patient-perceived importance and factor analysis; four domains were identified (self-perception, role-emotional, role-social, acne symptoms). After pilot-testing for comprehension in acne subjects, further revisions were made to improve clarity and applicability. The resulting instrument takes 10 minutes to complete, and consists of 24 questions assessing how acne affected certain aspects of patients' lives during the past week on a 7-point scale. Thus, an instrument with excellent content validity was developed to assess health-related quality of life in patients with facial acne, and is comprised of statistically meaningful items of importance to patients. Other measurement characteristics are being assessed in a recently initiated study to evaluate test-retest reliability and responsiveness to therapy.

Acne Vulgaris↗

PubMed1995

Activity of the type 1 5 alpha-reductase exhibits regional differences in isolated sebaceous glands and whole skin.

The presence of 5 alpha-reductase (5 alpha-R) in skin may indicate that the androgen regulation of sebaceous glands and sebum production requires the local conversion of testosterone to dihydrotestosterone. The goals of this study were to identify which isozyme of 5 alpha-R (type 1 or type 2) is expressed in sebaceous glands from facial areas, scalp, and non-acne-prone areas; to determine if 5 alpha-R activity is concentrated in sebaceous glands; to assess whether there are regional differences in this enzyme's activity; and to test the effects of azasteroid inhibitors and 13-cis retinoic acid on 5 alpha-R in these tissues. Sebaceous glands were microdissected from facial skin, scalp, and non-acne-prone skin (arm, breast, abdomen, leg), and the activity of 5 alpha-R was determined. A total of 49 samples from 23 male and 21 female subjects without acne (age range, 16 to 81 years, 56 +/- 20 years [mean +/- SD]) was analyzed. The biochemical properties of the enzyme in each of the samples tested are consistent with those of the type 1 5 alpha-R. Minimal to no type 2 5 alpha-R was detected. The level of 5 alpha-R activity was significantly higher in the sebaceous glands compared to whole skin in facial skin (p = 0.047), scalp (p = 0.039), and non-acne-prone skin (p = 0.04). Enzyme activity in sebaceous glands from facial skin and scalp was significantly higher than in a comparable amount of sebaceous gland material obtained from non-acne-prone areas (32 +/- 6 [mean +/- SEM]), 35 +/- 7 (mean +/- SEM) versus 6.0 +/- 3.0 (mean +/- SEM) pmol/min/mg protein, p = 0.014 and 0.007, respectively). Finasteride and 13-cis retinoic acid were poor inhibitors of the enzyme with 50% inhibitory concentration values greater than 500 nM. These data demonstrate that in the skin from older patients without acne the type 1 isozyme of 5 alpha-R predominates, its activity is concentrated in sebaceous glands and is significantly higher in sebaceous glands from the face and scalp compared to non-acne-prone areas, and the action of 13-cis retinoic acid in the control of acne is not at the level of 5 alpha-R. Furthermore, we suggest that specific inhibition of the type 1 5 alpha-R may offer a viable approach to the management of sebum production and, hence, acne.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗