Flare and itch induced by substance P in human skin.

Intradermal injection of synthetic substance P (10(-7)--10(-5) M in humans produced flare, wheal and itching. These responses were inhibited by oral pretreatment of the subjects with an antihistaminic drug (chlorcyclizine) or by local pretreatment with Compound 48/80 administered to deplete the local stores of mast-cell bound histamine. The findings indicate that the responses induced by substance P were mainly mediated by histamine released from the dermal mast cells. In contrast to previously studied histamine liberators, substance P was less potent when acting on rat mast cells in vitro than on human skin mast cells in vivo. When incubated with rat peritoneal mast cells, about 100 times higher concentrations (10(-5) M) were required to induce histamine release than in the in vivo studies on humans. It was concluded that substance P is a potent histamine liberator in human skin.     

Neurogenic modifications induced by substance P in an organ culture of human skin.

Neurogenic inflammation of the skin observed after topical application of an irritant substance or environmental stimulation induces vascular changes and the production of inflammatory mediators. Substance P (SP) is one of the main neuropeptides which trigger an inflammatory response in the skin. So, with the aim to develop an alternative method to study neurogenic inflammation of the skin, we used an organ culture of human skin. SP was added onto epidermis or directly to culture medium in an attempt to reproduce ex vivo the effects described in vivo. Even disconnected from systemic blood circulation, in skin fragments in culture, we observed dose-dependent edema, vasodilation and extravasation of lymphocytes and mast cells through the microvascular wall. Moreover, the release of proinflammatory mediators interleukin 1alpha and tumor necrosis factor alpha was evidenced.     

神经生长因子和P物质与皮肤病

神经生长因子和P物质同属多肽类物质，可使肥大细胞脱颗粒释放组胺，趋化炎性因子聚集，引起神经源性炎症；其直接作用于微血管可引起血管扩张、血浆溢出；促进黑素细胞生成，刺激黑素颗粒转运等。这些过程与许多皮肤病如特应性皮炎、银屑病、白癜风等的发生密切相关。     

Firm stroking of human skin leads to vasodilatation possibly due to the release of substance P

Many animal species invest a large amount of time in grooming behavior without deriving any apparent benefit. In order for this behavior to have survived, however, it must confer some survival advantage. In seven of eight humans tested, an elevation in the skin's temperature was documented after massaging of the cheeks of the face. The elevation of the skin's temperature reached a plateau after about 40 min of massaging and was correlated to visible erythema. This effect could be inhibited by repeated pretreatment of the skin with topical capsaicin, a chemical that results in the release of substance P from peripheral nerve endings. Thus, it appears that the temperature elevation induced by stroking of human skin is controlled, at least in part, by release of the neurotransmitter, substance P. In conclusion, it appears that the release of neurotransmitter(s) may be the survival advantage that grooming confers to animals.     

Characterization of [3H]substance P binding sites in human skin

Radioligand binding experiments were performed with crude homogenates from normal human skin in order to investigate substance P receptor density. Binding of [³H]substance P ([³H]SP) reached equilibrium after 20 min and was saturable; analysis of saturation curves gave a significantly better fit using two-site binding compared to the single-site model. Competition studies employing some selective agonists for NK1, NK2 and NK3 receptors have demonstrated that only the NK1 selective agonist, [Sar⁹, Met(O₂)¹¹]-SP, was a competitor for [³H]SP binding. In addition, the non-hydrolyzable guanosine 5'-0-(3-thiotriphosphate) altered the dissociation of SP from NK1 receptors by increasing the number of low-affinity sites. These data show that in the skin [³H]SP binds to a single population of substance P high-affinity sites, which represent NK1-type receptors.     

Glycosaminoglycans in human skin

Small skin biopsies of thirty-nine human subjects were assayed for the qualitative and quantitative analysis of glycosaminoglycans. The following results were obtained:

• 1 Besides the presence of hyaluronic acid and dermatan sulphate, evidence has been presented for the presence of heparan sulphate.
• 2 The content of glycosaminoglycans was higher in biopsies from healthy individuals than the values reported for post-mortem human skin.
• 3 Variation of the concentration of either hyaluronic acid or dermatan sulphate plus heparan sulphate in relation to the region of the body could not be demonstrated.
• 4 With advancing age a decrease in dermatan sulphate plus heparan sulphate could be demonstrated. However, hyaluronic acid content could not be demonstrated to correlate with age.

     

组织蛋白酶在皮肤科的研究进展

组织蛋白酶是溶酶体内的蛋白水解酶,与多种器官的纤维化和肿瘤有密切关系.近儿年,组织蛋白酶在皮肤科的研究主要集中于:其在正常表皮分化、毛囊形成、皮肤损伤修复及瘢痕形成中的作用;与多种慢性炎症性皮肤病的相关性;对其与皮肤肿瘤发生、转移关系的研究已深入至细胞信号与基因调控,并初涉基因治疗领域.     

Carotenoids in human skin

The interaction of free radicals with antioxidants is a topic of increasing interest in the development of prevention strategies against skin ageing. Carotenoids can serve as marker substances for the complete antioxidative network of human skin. Recently, it has become possible to measure the carotenoids non-invasively and online using resonance Raman spectroscopy. This method has been used in various studies to investigate the interaction of carotenoid antioxidants and free radicals in human skin. In this review, the results of the selected studies are summarized and compared. It could be demonstrated that the carotenoid concentration of the skin reflects the lifestyle of individuals. A high level of carotenoids can be achieved with a healthy diet rich, for instance, in fruit and vegetables. Stress factors such as illness, UV and IR radiation of the sun, and smoking and alcohol consumption reduce the concentration of the carotenoids in the skin. It could be demonstrated that premature skin ageing was less in people with a high level of antioxidants in their tissue. Consequently, the furrows and wrinkles were not so deep and dense as in the skin of individuals with a low antioxidant level. The measurements are highly suited for the development of anti-ageing strategies and can be efficiently used in the medical diagnostics and therapy control.     

Combining confocal Raman microscopy and freeze‐drying for quantification of substance penetration into human skin

In the area of dermatological research, the knowledge of rate and extent of substance penetration into the human skin is essential not only for evaluation of therapeutics, but also for risk assessment of chemicals and cosmetic ingredients. Recently, confocal Raman microscopy emerged as a novel analytical technique for analysis of substance skin penetration. In contrast to destructive drug extraction and quantification, the technique is non‐destructive and provides high spatial resolution in three dimensions. However, the generation of time‐resolved concentration depth profiles is restrained by ongoing diffusion of the penetrating substance during analysis. To prevent that, substance diffusion in excised human skin can instantly be stopped at defined time points by freeze‐drying the sample. Thus, combining sample preparation by freeze‐drying with drug quantification by confocal Raman microscopy yields a novel analytical platform for non‐invasive and quantitative in vitro analysis of substance skin penetration. This work presents the first proof‐of‐concept study for non‐invasive quantitative substance depth profiling in freeze‐dried excised human stratum corneum by confocal Raman microscopy.     

Xenobiotic metabolizing enzymes in human skin and SkinEthic reconstructed human skin models

Skin metabolism is becoming a major consideration in the development of new cosmetic ingredients, skin being the first organ exposed to them. In order to replace limited samples of Excised human skin (EHS), in vitro engineered human skins have been developed. 3D models are daily used to develop and evaluate new cosmetic ingredients and have to be characterized and compared with EHS in terms of metabolic capabilities. This work presents the determination of apparent catalytic parameters (apparent Vmax, Km and the ratio Vmax/Km) in 3D models compared with EHS for cytochrome P450 dependent monooxygenase isoforms involved in drug metabolism, esterases, alcohol dehydrogenases, aldehyde dehydrogenases, peroxidases, glutathione S‐transferases, N‐acetyl transferases, uridinyl diphosphate glucuronyl transferases and sulfotransferases. Results show that all these enzymes involved in the metabolism of xenobiotics are expressed and functional in the EHS and 3D models. Also, the Vmax/Km ratios (estimating the intrinsic metabolic clearances) show that the metabolic abilities are the most often comparable between the skin models and EHS. These results indicate that the 3D models can substitute themselves for EHS to select cosmetic ingredients on the basis of their metabolism, efficacy or/and safety.     

Prostaglandins in human skin disease

A variety of different, experimentally induced human skin inflammatory stimuli including UV-A (Barr et al ., 1982a; Gilchrest et al ., 1982), UV-B (Black et al ., 1978, 1980; Hensby et al ., 1980; Black, Hensby & Greaves, 1982), UV-C (Camp et al ., 1978), infra-red (Hensby et al ., 1982), trafuril (Plummer et al ., 1977) and anthralin (Barr et al ., 1982b) cause marked and prolonged elevations of the recoverable levels of arachidonic acid and its cyclo-oxygenase products.
The known pharmacology of many prostanoids (products of the prostaglandin cyclo-oxy-genase system) including vasodilatation and synergism with other inflammatory mediators (Hensby, Kingston & Greaves, 1976; Camp, 1982) would suggest a role for prostanoids in various human skin diseases, particularly those associated with an inflammatory component. We now report the preliminary results that we have obtained for the recoverable levels of four prostanoids, namely PGE₂, PGD₂, PGF_2x, and 6-oxo-PGF_1x in four human skin disorders, viz. psoriasis, tuberculin delayed hypersensitivity, vitiligo and scleroderma.     

Lipase expression in human skin

We have used a monoclonal antibody against human pancreatic lipase to study the immunohistochemical expression of lipase in formalin-fixed, paraffin-embedded biopsy specimens from normal and a variety of tumoral and inflammatory skin diseases. In normal skin, lipase is detected in the sebaceous glands and in the external root sheath of the hair follicle. Antibody to lipase might be a valuable reagent to help confirm sebaceous and follicular differentiation in adnexal tumors. Immunoreactivity to lipase is also detected within mononuclear phagocytes in situations where extracellular release of lipids occurs, such as in xanthomas or in inflammation of the fat with significant lysis of adipocytes. The antibody to lipase identifies a major protein in pilosebaceous homogenates of 42.7 kDa following immunoblotting.     

Androgen receptor in human skin

Cytosol androgen receptor was assayed in 18 human skin biopsies by an exchange technique with a labelled potent synthetic androgen, methyltrienolone (R 1881), under conditions which measured total (i.e. both free and occupied) binding sites. Androgen binding sites were only present in skin biopsies from patients with marked seborrhoea often accompanied by acne (8 cases) and no sites were detected in normal skin biopsies (7 cases). Three biopsies from seborrhoeic patients, however, did not contain androgen receptor. Although no direct quantitative correlation could be drawn between binding site concentration and sebum excretion, it would seem that the androgen receptor content nevertheless constitutes an important parameter in the study of the hormonal control of seborrhoea.