Dermal connective tissue modulated by pharmacologic agents

Final Report on the Safety Assessment of Ascorbyl Palmitate, Ascorbyl Dipalmitate, Ascorbyl Stearate, Erythorbic Acid, and sodium Erythorbate

Ascorbyl Palmitate, Ascorbyl Dipalmitate, Ascorbyl Stearate, Erythorbic Acid, and Sodium Erythorbate are related ingredients that function as antioxidants in cosmetic formulations. Ascorbyl Palmitate, Ascorbyl Dipalmitate, and Ascorbyl Stearate are esters and diesters of ascorbic acid with long-chain fatty acids. Erythorbic Acid is a stereoisomer of ascorbic acid and Sodium Erythorbate is the sodium salt of Erythorbic Acid. Although all of these ingredients are used, uses of Ascorbyl Palmitate and Erythorbic Acid predominate, with combined uses in over a thousand cosmetic formulations at low concentrations. Ascorbyl Palmitate is used at concentrations between 0.01 and 0.2% , and Erythorbic Acid is used at concentrations of 0.5-1% . Ascorbyl Palmitate has vitamin C activity approximately equal to that of L-ascorbic acid, whereas Erythorbic Acid has only 5% activity. The esters are likely to penetrate the skin readily, but the acid and its salt are not likely to penetrate. These ingredients exhibit low acute oral toxicity in animals. In chronic feeding studies, decreased body weight gain, the formation of oxalate stones in the bladder, and hyperplasia were seen in rats fed high levels of Ascorbyl Palmitate. Ascorbyl Palmitate (10%) and Ascorbyl Dipalmitate (100%) were not irritating to the intact skin of albino rabbits. Ascorbic Acid (30 % ) itself caused barely perceptible erythema and Sodium Erythorbate powder caused no irritation to the intact and abraded skin of rabbits. In animal studies, Ascorbic acid was not a sensitizer, and Erythorbic Acid (10%) applied topically to porcine skin reduced ultraviolet B (UVB)-induced phototoxicity. In clinical studies, Ascorbyl Palmitate caused no dermal irritation or sensitization. These ingredients are minimally irritating to the eye. Sodium Erythorbate did not cause fetal or maternal toxicity or developmental toxicity in rats and mice fed high levels. Although these ingredients were generally negative in a wide range of genotoxicity tests, Erythorbic Acid and Sodium Erythorbate did produce isolated positive genotoxicity test results. As antioxidants, these ingredients have been studied in animals after initiation with various carcinogens. In some cases reductions in tumor incidence were seen, in others no effect was noted. In no case did treatment with these ingredients increase tumor incidence. The highest use concentrations of Erythorbic Acid and Sodium Erythorbate are in oxidative hair dyes, where they are completely consumed in the chemical reaction that takes place at mixing. The fatty acid esters of ascorbic acid are used at lower concentrations in leave-on formulations. In consideration of these uses and based on the available safety test data, Ascorbyl Palmitate, Ascorbyl Dipalmitate, Ascorbyl Stearate, Erythorbic Acid, and Sodium Erythorbate are safe for use as cosmetic ingredients in the present practices of use.

Effect of propolis on mast cells in wound healing

Wound healing is divided into three phases: inflammatory, proliferative and remodeling. Mast cells participate in all these phases. The aim of the present study was to determine the effects of propolis on the population of mast cells in oral surgical wounds in comparison to the results obtained with dexamethasone. This study was prospective, in vivo, randomized, semiexperimental, quantitative and comparative animal. A circular surgical wound was made on the dorsum of the tongue of 90 hamsters divided into three experimental groups: topical application of 30% propolis alcoholic extract (Group 1); 0.1% dexamethasone in orabase cream (Group 2); and orabase cream alone (Group 3). Applications were performed every 12 h throughout the experiment. The postoperative times for killing of the animals were 1, 3, 7, 14 and 28 days. The Student's t test for independent samples was employed in the statistical analysis. In the inflammatory phase of healing, propolis caused a greater reduction in the number of mast cells on the edge and in the central region of the surgical wound in comparison to dexamethasone. Moreover, the number of mast cells on day 1 was lower in the central region of the wounds treated with the orabase cream alone in comparison to dexamethasone. In conclusion, the anti-inflammatory action of propolis mediated by mast cells was more effective than dexamethasone in the inflammatory phase of healing.

Corpus luteum function and regression

Several conclusions can be drawn from a review of the formation, function and regression of the corpus luteum. Ovulation and luteinization encompass degenerative and growth changes. Inflammatory conditions associated with ovulation lead to the breakdown of the follicle wall and the membrana granulosa, along with initial damage to theca and granulosa cells. The early corpus luteum is, therefore, a tissue in stress. Thus, one view of the corpus luteum is that it, like the phoenix, rises from the inflammatory ashes of the postovulatory follicle to exist briefly and to be consumed by a similar process at regression. The luteinization process is associated with parenchymal cell hypertrophy and matrix remodelling, which appear to be regulated by IGFs and androgens, and with angiogenesis, which is induced mostly by bFGF. High levels of functional activity of the corpus luteum are regulated by control at the level of the LH receptor, whose activation leads to the translocation of cholesterol into the cell and mitochondria for conversion to steroids. Functional luteal regression can be considered as another inflammatory-like condition with apparent activation of the immune system, along with cytokine, reactive oxygen, and eicosanoid production. Structural luteolysis is subsequently invoked that leads to matrix dissolution and cellular degeneration. It is perhaps not surprising that the invocation of immune activation, which causes the production of DNA-damaging reactive oxygen species and cytotoxic cytokines each cycle, may increase the risk of pathologies. One example may be ovarian cancer which appears to be associated with the use of fertility-enhancing drugs and associated with the number of ovulations in a woman's lifetime.

Action of topical thyroid hormone analogue, triiodothyroacetic acid in reversing glucocorticoid-induced skin atrophy in humans

The present study concerns the effect of topical treatment with a cream formulation of triiodothyroacetic acid (TRIAC) in comparison with a placebo preparation in producing a reversal of skin atrophy induced by long-term employment of topical glucocorticoid therapy in humans. A total of 39 patients with clinically verified skin atrophy due to long-term use of topical potent glucocorticoids were randomized. The changes in skin thickness, elastic fibers, and hyaluronic acid were evaluated by means of sonography and histology. After 8 weeks' treatment, the skin thickness measured by sonography increased by 16% in the epidermis, 8% in the dermis, and epidermis + dermis in the placebo group. In the TRIAC 0.1% group, the corresponding values were 24% ( p=0.063) in the epidermis, 28% ( p=0.042) in the dermis, and 25% ( p=0.039) in the epidermis + dermis. After 8 weeks, in the placebo group, the skin thickness measured by biopsy increased by 5% in the epidermis, epidermis + dermis, and 6% in the dermis. In the TRIAC 0.1% group, the corresponding values were 31% ( p=0.041) in the epidermis, 46% ( p=0.041) in the dermis and 44% ( p=0.043) in the epidermis + dermis. After 8 weeks, the elastic fibers of moderately irregular and thickened fibers increased by 56% in the placebo group and 100% ( p=0.043) in the TRIAC 0.1 group. This study indicates that topical treatment with TRIAC appears to reverse glucocorticoid-induced skin atrophy under the narrow conditions tested.

Action of topical thyroid hormone analogues on glucocorticoid-induced skin atrophy in mice

Previously we demonstrated the stimulation of collagen synthesis in triiodothyroacetic acid (TRIAC)-topically treated human and mice. In the present study, we have evaluated the dose response effect of thyroid hormone (TH) analogues and tretinoin on glucocorticoid-induced skin atrophy in a haired mouse model. For this investigation, we treated haired mice twice daily for 7 days with various topically administered doses of TRIAC, triiodothyronine-sodium salt (T(3)-Na), diiodothyroacetic acid (DIAC), 3,5-diiodothyropropionic acid (DITPA), and tretinoin with 0.2 mM betamethasone17-valerate (BM), or with the vehicle as a control group. We also investigated a combination of commercial betamethasone dipropionate (BD) 0.05% cream and various doses of TRIAC on mouse skin. TRIAC was able to reverse the skin atrophy by 25% in a daily dose of 1 nmol/cm(2) in the presence of 0.2 mM BM (p < 0.05). Neither other TH analogues nor TRIAC in lower and higher concentrations had a significant inhibitory effect on dermal atrophy (p > 0.05). A combination of 0.2 mM BM and 10 nmol/cm(2) TRIAC was able to prevent dermal atrophy by 18%. The addition of TRIAC to 0.05% BD cream in a final concentration of 0.1% was able partially to reverse the dermal atrophy by 15% (p < 0.05). TRIAC alone in a concentration of 1,000 nmol/cm(2) stimulated dermal proliferation by 34% (p < 0.05). Other TH analogues alone had no stimulatory effect on dermal proliferation. Tretinoin 0.8 mM was able to inhibit dermal atrophy by 20% (p < 0.05) and had an effect on dermal thickness of 85% (p < 0.05). However, severe side effects with edema, erythema, and scaling were commonly observed in all tretinoin-treated mouse skin, which could partly explain the increase in dermal thickness. In contrast, no skin side effects were observed after treatment with TRIAC. This study indicates that TRIAC may have a therapeutic effect on BM-induced dermal atrophy in mouse skin and a direct stimulatory effect on dermal proliferation when given alone.

Molecular basis of the alteration in skin collagen metabolism in response to in vivo dexamethasone treatment: effects on the synthesis of collagen type I and III, collagenase, and tissue inhibitors of metalloproteinases

BACKGROUND

Glucocorticoids are widely used for the treatment of various diseases, despite known side-effects such as skin atrophy. Many studies have shown that the status of collagen fibres in the skin is affected by glucocorticoid treatment. However, the molecular mechanism underlying the alteration of collagen metabolism in the skin by glucocorticoid treatment remains unknown.

OBJECTIVES

To characterize the molecular mechanisms related to the deterioration of the dermis in response to glucocorticoids, the status of two major types of collagen, collagenase, and tissue inhibitors of metalloproteinases (TIMPs) in the dorsal skin of rats was studied at the protein and mRNA levels.

METHODS

Samples of rat dorsal skin were obtained after daily (1 mg kg-1) subcutaneous injections of dexamethasone (DEX) for 8 days. mRNA levels of two types of collagen and of TIMPs were measured by a lysate RNase protection assay. mRNA levels of collagenase were measured by a quantitative polymerase chain reaction. Protein levels of collagen and collagenase were measured by an immunoblot analysis.

RESULTS

Levels of type I tropocollagen and type III tropocollagen were drastically reduced in response to DEX. The effects of DEX treatment were more severe on type III than type I collagen: it also produced a significant decrease in fibril collagen of type III collagen. DEX treatment was found to decrease both active and latent forms of collagenase as well as its mRNA levels. Among TIMPs, mRNA levels of TIMP-1 and TIMP-2 were decreased in response to DEX treatment, whereas those of TIMP-3 were not affected.

CONCLUSIONS

These results suggest that DEX treatment strongly interferes with both the synthesis and degradation of type I collagen and, more drastically, type III collagen, the molecule that is known to play a major role in the initiation of wound healing. The present study may provide a molecular basis for the deterioration of skin function, impaired wound healing, and skin atrophy caused by glucocorticoid treatment.

Effect of penicillin G on corium thickness in linear morphea of childhood: An analysis using ultrasound technique

Linear morphea is the most common form of localized scleroderma in children. The pathogenesis of this disorder is unknown. We report a child with a 6-year history of linear morphea in whom intravenous administration of 5 MU aqueous penicillin G three times a day for 10 consecutive days caused reduction in the thickness of the corium as demonstrated by ultrasound measurements.

Cutaneous lymphangiectases associated with severe photoaging and topical corticosteroid application

We report an elderly patient with lymphangiectases arising within skin affected by photoaging, steroid atrophy, and inflammation. Bullous lesions appeared in several sites following a year of topical corticosteroid applications for neurodermatitis. Light and electron microscopy showed that the bullae consisted of dilated lymphatic vessels within the dermis. There was also marked nodular elastosis and attenuation of dermal collagen. We suggest that this patient's lymphangiectases resulted from abnormal structure and function of the dermis due to photoaging and steroid atrophy.

Effects of dexamethasone and cell proliferation on the expression of matrix metalloproteinases in human mucosal normal and malignant cells

Matrix metalloproteinases (MMPs) have an important role in many biological processes, such as tumor metastasis, wound healing, and inflammation. The regulation of MMPs and their inhibitors is still not known in detail, and the aim of this study was to investigate the effects of dexamethasone on cultured oral benign and malignant cell lines. The expression of MMPs in culture was studied: in four gingival (GF) and one periodontal ligament (PLF) fibroblast cell lines; in six gingival keratinocyte (GK) cell lines; and in UNR (UNR-108, rat osteogenic sarcoma) and SCC (SCC-25, human tongue squamous cell carcinoma) cell lines. In the GFs, PLFs, and UNR cells, only MMP-2 (72 kDa gelatinase) was detected by gelatin zymography, while in most of the GK cell lines only MMP-9 (92 kDa gelatinase) was observed. In confluent SCC cultures, both MMP-2 and MMP-9 were found, while only MMP-2 was seen in rapidly growing SCC cells, demonstrating that cell proliferation influenced gelatinase expression in these cells, but not in the other cell lines studied. Dexamethasone at concentrations of 10(-5) mol/L and 10(-7) mol/L decreased the production of gelatinases in the GFs and PLFs, but not in the GKs, SCC, or UNR cells. The expression of mRNAs for matrix metalloproteinases (MMP-1 [interstitial collagenase] and MMP-2) and their inhibitors (TIMP-1 and TIMP-2) was also studied in the GFs by Northern hybridization. Dexamethasone markedly decreased the amount of MMP-2 mRNA in the GFs. The mRNA level of MMP-1 decreased even more in the same GFs. The mRNA levels for TIMP-1 and TIMP-2 were also decreased by dexamethasone in the GFs. Cell proliferation influenced the degree to which dexamethasone decreased these mRNA levels. The results indicate that glucocorticoids decrease the levels of MMPs and TIMPs in oral fibroblastic cells, whereas they do not appear to affect the production of gelatinases in either normal or malignant oral epithelial cell lines.

Mechanical properties of keloids in vivo during treatment with intralesional triamcinolone acetonide

The mechanical properties of 17 keloids in 9 patients before and during treatment with intralesional triamcinolone acetonide were studied using a recently developed noninvasive suction device for measuring skin elasticity in vivo. Each keloid was treated with intralesional injections of 10 mg/ml triamcinolone acetonide without local anaesthetic at intervals of 3 weeks. A total of four measurements per keloid were performed, before treatment and 3 weeks after the first, second and third treatments. The parameters used were: immediate distension (Ue), delayed distension (Uv), immediate retraction (Ur) and final distension (Uf). Relative parameters independent of skin thickness were calculated: Uv/Ue, the ratio between the viscous and the elastic deformation of the skin, and Ur/Uf, representing the ability of the skin to return to its initial position after deformation (biological elasticity). After three injections of triamcinolone acetonide a marked decrease in Uv/Ue and a less-pronounced increase in Ur/Uf compared with baseline values was observed. These findings indicate that the main effect of intralesional steroids on the connective tissue of keloids is a decrease in viscosity due to a loss of ground substance. This method provides a noninvasive quantitative assessment of the mechanical properties of scars and is well suited to comparative studies on the efficacy of various scar therapies.

Systemic glucocorticoids decrease the synthesis of type I and type III collagen in human skin in vivo, whereas isotretinoin treatment has little effect

The effects of systemic glucocorticoid and isotretinoin treatments on type I and type III collagen synthesis in intact skin were investigated by measuring the carboxyterminal and aminoterminal propeptides of type I procollagen, and the aminoterminal propeptide of type III procollagen, in suction blister fluid (SBF), in a study of 27 patients. All three parameters were significantly lower in the SBF of glucocorticoid-treated patients than in controls or patients undergoing treatment with isotretinoin, whereas the latter two groups did not differ significantly from each other. During glucocorticoid treatment, the concentrations of the procollagen propeptides were only about 20% of the corresponding control values, indicating that systemic therapy with prednisone at a dose of 0.48 mg/kg per day almost totally abolishes collagen synthesis in the skin. These results indicate that systemic glucocorticoid treatment suppresses the synthesis of both type I and type III collagen in the dermis, and suggest that many side-effects of these drugs, such as atrophy of the skin, are due to this inhibition. Systemic isotretinoin treatment did not stimulate skin collagen synthesis. Thus, its regenerative effect on connective tissue may be mediated by mechanisms other than direct stimulation of collagen synthesis.

Serum markers of collagen synthesis and degradation in skin diseases. Altered levels in diseases with systemic manifestation and during systemic glucocorticoid treatment

Serum concentrations of the markers of collagen synthesis and degradation, collagen I propeptide (PICP), collagen III propeptide (PIIINP) and the cross-linked telopeptide of type I collagen (ICTP) were measured in young male dermatological patients and in control subjects. No significant differences were noted between patients suffering from atopic eczema (n = 24), other eczemas (n = 11), acne (n = 8), psoriasis (n = 7) or tinea (n = 9) and the control subjects (n = 24). In the total study population representing patients with common skin diseases and control subjects there was a significant correlation between the serum concentrations of PICP and PIIINP and between the concentrations of PICP and ICTP. This suggests that synthesis of type I and III collagens in vivo is coordinated and that the degradation and synthesis of type I collagen is balanced. These markers were also measured in older patients suffering from psoriasis, eczema and various connective tissue diseases. It was noted that the degree of skin involvement in these diseases was not related to the serum concentrations of the markers of collagen metabolism. The highest levels of PICP and PIIINP were observed in a patient with systemic mastocytosis (PICP 309 micrograms/l and PIIINP 8.0 micrograms/l). Increased levels of PIIINP were also found in patients with a high alcohol consumption. We have previously demonstrated that systemic glucocorticoids reduce collagen propeptide levels in serum. In the present study we also proved that systemic glucocorticoids have no effect on collagen degradation.(ABSTRACT TRUNCATED AT 250 WORDS)