炎症浸润细胞在曝光和非曝光部位皮肤中的组织学表现

目的 观察、比较曝光及非曝光部位皮肤中炎症浸润细胞的类型、数目,探讨其在光老化过程中的作用.方法 应用免疫组化法分别对23例女性健康志愿者前臂伸侧(曝光)和上臂内侧(非曝光部位)皮肤石蜡标本中的细胞表面抗原CD3、CD45RO、CD68进行检测,计数阳性细胞数目.不同部位阳性细胞数比较采用配对t检验,阳性细胞数与年龄的相关性采用Pearson相关分析.结果 曝光部位皮肤组织CD3、CD45RO、CD68阳性细胞数分别为(48.91±13.17)/mm2、(46.83±12.92)/mm2、(85.43±22.35)/mm2,非曝光部位分别为(40.61±11.57)/mm2、(38.00±10.11)/mm2、(73.48±16.21)/mm2,曝光部位均显著高于非曝光部位(P<0.01或<0.05).曝光部位皮肤组织CD3、CD45RO阳性细胞数与年龄呈正相关(r=0.56、0.56,P<0.01),曝光部位CD68及非曝光部位皮肤组织CD3、CD45RO、CD68阳性细胞数与年龄无相关性.结论 T淋巴细胞、巨噬细胞可能在光老化过程中发挥作用.

Abstract：

Objective To investigate the role of infiltrating inflammatory cells in photoaging process by comparing the type and number of these cells in sun-exposed and-unexposed skin.Methods The expression of CD3,CD45RO and CD68 were detected by immunohistochemieal staining in 46 paraffin-embeded skin samples from the extensor forearms(sun-exposed)and upper-inner arms(sun-unexposed) of 23 healthy female volunteers.The number of positive cells in sun-exposed and -unexposed sites was counted and statistically tested by paired samples t test,and Pearson correlation analysis was performed to assess the relationship between the number of positive cells and age of these volunteers.Results The number of cells positive for CD3,CD45RO and CD68 per square millimetre in sun-exposed skin was significantly higher than that in sun-unexposed skin(48.91±13.173 vs.40.61±11.571,46.83±12.915 vs.38.00±10.109,85.43±22.346 vs.73.48±16.208,respectively,P<0.01 or 0.05).The number of cells positive for CD3 and CD45RO increased significantly with age (r=0.557,0.555,respectively,both P<0.01) in the sun-exposed skin but not in sun-unexposed skin,and the number of CD68-positive cells was uncorrelated with age in either sunexposed or -unexposed skin.Conclusion T lymphocytes and macrophages may play a role in the process of photoaging.     

人皮肤鳞状细胞癌A431细胞株电压门控钾通道的研究

目的 探讨电压门控钾通道在人皮肤鳞状细胞癌A431细胞和人角质形成细胞HaCaT细胞中的作用.方法 噻唑蓝方法研究加入含有不同浓度四乙胺的培养基对A431细胞和HaCaT细胞的增殖的影响;提取体外培养A431细胞、HaCaT细胞以及人正常表皮组织的蛋白,ELISA方法检测电压门控钾通道蛋白(HERG)在它们中的表达,比较它们的差异.结果 四乙胺对体外培养的A431细胞和HaCaT细胞的增殖抑制效应具有时间依赖与剂量依赖的特点,当四乙胺的浓度≥10 mmol/L且作用时间≥24 h,可以使A431细胞和HaCaT细胞的增殖受到明显的抑制.HERG钾通道蛋白在A431细胞、HaCaT细胞和人正常皮肤表皮组织均有表达,平均浓度分别为(49.7114±3.55696)pg/ml、(35.7471±4.14696)pg/ml、(36.8857±3.47810)pg/ml,组间比较差异具有统计学意义(P<0.05).结论 阻断电压门控钾通道可抑制A431细胞和HaCaT细胞的增殖;电压门控钾通道可能在人皮肤鳞状细胞癌细胞上的表达更显著.

Abstract：

Objective To investigate the role of voltage-gated potassium channel in the human skin squamous cell carcinoma A431 cells and human keratinocyte HaCaT cells. Methods MTT assay was performed to detect the effect of different concentrations of tetraethylammonium (TEA) on the proliferation of cultured A431 cells and HaCaT cells. Besides, enzyme-linked immunosorbent assay (ELISA) was conducted to detect the expression of HERG channel protein in A431 cells, HaCaT cells and normal human skin tissue.Results TEA inhibited the proliferation of A431 cells and HaCaT cells in a dose- and time-dependent manner.After treated with TEA (≥ 10 mmol/L) for 24 or more hours, the proliferation of A431 cells and HaCaT cells was obviously suppressed. A significant difference was observed in the average concentration of HERG channel protein between A431 cells, HaCaT cells and normal human skin tissue (49.7114 ± 3.55696 pg/ml, 35.7471 ±4.14696 pg/ml, 36.8857 ± 3.47810 pg/ml, all P < 0.05). Conclusions The block of voltage-gated potassium channel could inhibit the proliferation of A431 cells and HaCaT cells, and the expression of voltage-gated potassium channel seems to be higher in human skin squamous cell carcinoma cells.     

Human β-defensin-2 and skin diseases

Human β-defensin-2 (hBD-2) is an endogenous antimicrobial peptide recently found in the skin with broad-spectrum antimicrobial activity and unique mechanism of function. Recent studies have confirmed that the expression of hBD-2 is upregulated in the lesions of some dermatoses, such as psoriasis,acne vulgaris, verruca, dermatophytosis and basal cell carcinoma, etc. The susceptibility to bacterial and viral infections may be associated with the decreased or absent expression of hBD-2. Further researches into HBD-2will provide a new direction for the prevention and treatment of skin diseases.     

Photodynamic therapy with topical aminolevulinic acid

Photodynamic therapy(PDT) is a relatively new therapy in dermatology that uses the topical application of a porphyrin derivative to selectively destroy a cutaneous target. The action is implemented by the application of a specific light frequency. The ability of porphyrin to selectively target tumor tissue has been known since the 1960 s. In the late 1970 s, the underlying mechanism was defined, and Dougherty's discovery of the first chromophore led to the production and commercialization of Photofrin. Many other chromophores that can act as photosensitizers have been studied since then, with aminolevulinic acid currently the most commonly used chromophore in clinical practice. PDT is simple, minimally invasive and can be administered on an outpatient basis. The efficacy of PDT has been proven for actinic keratosis, Bowen's disease and basal cell carcinoma; another of its well-known applications is the treatment of photoaging. Indications for its use are continuously increasing, and promising results are reported for various skin diseases. In this paper we report the mechanism of action of PDT with aminolevulinic acid, the literature concerning the most common diseases treated with PDT and the subsequent level of evidence.     

皮肤间质干细胞

皮肤干细胞的研究长期限定在表皮和毛囊隆突区,皮肤间质来源的干细胞和造血干细胞同样具有分化成脂肪细胞、平滑肌细胞、骨细胞、软骨细胞,甚至神经元和神经胶质细胞的潜能.毛囊周围结缔组织鞘、毛乳头和毛囊间真皮都可能含有多潜能干细胞,未来可能作为自体移植细胞治疗的潜在供体.主要概述皮肤问质干细胞的定位、表面标记、功能和潜在的临床应用价值.

Abstract：

For a long time,skin stem cell research has been focused on the epidermis and hair follicle bulge.It has been demonstrated that stem cells and hematopoietic stem cells from the mesenchymal compartments of the skin have the potential to differentiate into adipocytes,smooth muscle cells,osteocytes,chondrocytes,and even neurons and glia.The perifollicular connective tissue sheath,papilla and interfollicular dermis crystallize as the likely anatomic niche for these multipotent dermal cells; hence,they have the potential to function as an easily accessible,autologous source for stem cell transplantation.This article describes the location,surface antigens,function and potential applications of skin-derived mesenchymal stem cells.     

水通道蛋白-3与皮肤研究进展

Aquaporins (AQPs) are a group of membrane transport proteins involved in the transport ofwater across cell membranes. AQP3, the most abundant aquaporin subset in human skin, is permeable notonly to water but also to small solutes such as glycerol. It has been reported that AQP3-knockout mice havereduced stratum corneum water content, elasticity and impaired wound healing. AQP3 has been revealed to berelated to cell proliferation and migration, and involved in the initiation, progression and metastasis of tumors.In addition, AQP3 expression is associated with the pathogenesis of inflammatory cutaneous diseases such asatopic dermatitis and erythema toxicum neonatorum. AQP3 expression can be modulated by multiple factorssuch as retinoic acid and tumor necrosis factor α, and this modulation may provide a new clue for the therapyof related skin diseases.     

Malignant melanoma in the pediatric population

Controversial pigmented lesions in children are a problem for pathologist, clinicians and families that are confronted with this dilemma. Some skin lesions in this population defy diagnosis with pathologists split between a benign diagnosis and a cancer diagnosis. Three cases of controversial pigmented lesions in the pediatric population are presented. Three patients underwent radical resection of the controversial pigmented lesion, intra-operative lymphatic mapping and sentinel lymph node(SLN) biopsy. Due to the low morbidity of the SLN procedure a case is made to perform lymphatic mapping in this clinical scenario. If the SLNs are negative, not much is lost except for the scar and this becomes another line of evidence that perhaps the original lesion was benign. If the SLN shows metastatic cells, then the original skin lesion must be malignant and the patient is offered stage Ⅲ recommendations that would include complete node dissections and adjuvant Interferon therapy. This strategy provides for adequate treatment of the worse-case scenario, that the skin lesion is malignant. The cost to the patient is a low morbidity procedure, the SLN biopsy.     

Study of substance P and its receptor neurokinin-1 in psoriasis and their relation to chronic stress and pruritus

Substance P and its receptor(R) neurokinin (NK)-1 may have a role in the pathogenesis of psoriasis. Stress has been reported to play a role in the onset and exacerbation of psoriasis, which might include the substance P-NK-1 receptor(R) pathway. A feature of psoriasis, that has been correlated to the severity of stress and secretion of substance P, is pruritus. The objective of this study was to investigate the expression of substance P and the NK-1R in involved and noninvolved psoriatic skin, using a biotinylated streptavidin technique. Moreover, a possible correlation between the patient′s level of chronic stress, measured by salivary cortisol samples, degree of lesional pruritus, measured by means of a visual analogue scale, and the expression of substance P- and the NK-1R, was investigated. There was a low number of substance P positive nerve fibres in noninvolved and involved skin, the major immunoreactivity for substance P being found in inflammatory cells. The number of substance P- and NK-1R positive inflammatory cells was increased in involved compared to noninvolved psoriatic skin. The substance P positive cells were mostly lymphocytes, while most of the NK-1R positive cells were mast cells. NK-1R immunoreactivity was also seen as a reticular pattern in the upper part of the epidermis of involved skin in the majority of the patients. Low cortisol ratios in the patients, being an indicator of chronic stress, were correlated to an increased number of substance P- and NK-1R positive inflammatory cells in noninvolved psoriatic skin, and higher cortisol ratios to the presence of keratinocyte NK-1R immunoreactivity in involved skin. The degree of pruritus could not be correlated to the number of substance P positive fibers nor cells. Nonneuronal substance P and its receptor NK-1 might have a role in psoriasis, also during chronic stress.     

Responses of black and white skin to solar-simulating radiation: differences in DNA photodamage, infiltrating neutrophils, proteolytic enzymes induced, keratinocyte activation, and IL-10 expression

Black skin is more resistant to the deleterious effects of ultraviolet radiation than white skin. A higher melanin content and a different melanosomal dispersion pattern in the epidermis are thought to be responsible for this. Our purpose was to compare skin responses in black and white skin following exposure to solar-simulating radiation (SSR) to further investigate the photoprotective properties of black skin. Six volunteers of skin phototype I-III (white) were exposed to (doses measured directly with a Waldmann UV detector device) 12,000-18,000 mJ per cm2 (2 MED) of SSR and compared with six volunteers of skin phototype VI (black) exposed to 18,000 mJ per cm2 (<1 MED) of SSR. The presence and distribution of skin pigment, DNA photodamage, infiltrating neutrophils, photoaging associated proteolytic enzymes, keratinocyte activation, and the source of interleukin 10 (IL-10) in skin biopsies taken before and after exposure were studied. In all white skinned subjects, 12,000-18,000 mJ per cm2 of SSR induced DNA damage in epidermal and dermal cells, an influx of neutrophils, active proteolytic enzymes, and diffuse keratinocyte activation. Additionally, in three of the white skinned volunteers IL-10 positive neutrophils were found to infiltrate the epidermis. Except for DNA damage in the supra basal epidermis, none of these changes was found in black skinned subjects. Increased skin pigmentation appears to be primarily responsible for the observed differences in skin responses. Our data could provide an explanation as to why black skin is less susceptible to sunburn, photoaging, and skin carcinogenesis.     

皮肤老化和光老化中端粒-端粒酶机制研究进展

单纯南时间所致的人皮肤程序性或内源性老化及改变,与由环境损伤所致的多莺性损伤或外源性老化加速之间有着明显的不同,后者的进程主要由日光中的紫外线所介导,故称为光老化.端粒及端粒酶在细胞的生命周期中起着不容忽视的作用,与细胞的老化密切相关.皮肤内源性老化主要由细胞周期中进行性的端粒缩短所致,而在光暴露的皮肤,内源性老化的进程被环境因素所放大.     

Chronic actinic damage of facial skin

Chronic actinic damage of the skin manifests itself as extrinsic skin aging (photoaging) and photocarcinogenesis. During the last decade, substantial progress has been made in understanding cellular and molecular mechanisms of photoaging. DNA photodamage and ultraviolet-generated reactive oxygen species are the initial events that lead to most of the typical histologic and clinical manifestations of chronic photodamage of the skin. Chronic actinic damage affects all layers of the skin. Keratinocytes, melanocytes, fibroblasts, and endothelial cells are altered by ultraviolet radiation and can result in numerous changes in human skin, particularly the skin of fair-skinned individuals. These changes include actinic keratosis, thickening and wrinkling, elastosis, telengiectasia, solar comedones, diffuse or mottled hyperpigmentation, and skin cancers. There are many options in the treatment of changes caused by chronic actinic damage. The most effective measure of prevention of the photoaging and photocarcinogenesis is sun protection.     

C/EBPα expression is downregulated in human nonmelanoma skin cancers and inactivation of C/EBPα confers susceptibility to UVB-induced skin squamous cell carcinomas

Human epidermis is routinely subjected to DNA damage induced by UVB solar radiation. Cell culture studies have revealed an unexpected role for C/EBPα (CCAAT/enhancer-binding protein-α) in the DNA damage response network, where C/EBPα is induced following UVB DNA damage, regulates the G(1) checkpoint, and diminished or ablated expression of C/EBPα results in G(1) checkpoint failure. In the current study we observed that C/EBPα is induced in normal human epidermal keratinocytes and in the epidermis of human subjects exposed to UVB radiation. The analysis of human skin precancerous and cancerous lesions (47 cases) for C/EBPα expression was conducted. Actinic keratoses, a precancerous benign skin growth and precursor to squamous cell carcinoma (SCC), expressed levels of C/EBPα similar to normal epidermis. Strikingly, all invasive SCCs no longer expressed detectable levels of C/EBPα. To determine the significance of C/EBPα in UVB-induced skin cancer, SKH-1 mice lacking epidermal C/EBPα (CKOα) were exposed to UVB. CKOα mice were highly susceptible to UVB-induced SCCs and exhibited accelerated tumor progression. CKOα mice displayed keratinocyte cell cycle checkpoint failure in vivo in response to UVB that was characterized by abnormal entry of keratinocytes into S phase. Our results demonstrate that C/EBPα is silenced in human SCC and loss of C/EBPα confers susceptibility to UVB-induced skin SCCs involving defective cell cycle arrest in response to UVB.     

肥大细胞在慢性光损伤中的变化及研究进展

慢性光损伤是最常见的皮肤损害,由于长期接受紫外线照射所导致。研究表明,长期曝光部位皮肤中肥大细胞的数量较非曝光部位明显增多;肥大细胞在紫外线诱导的皮肤免疫抑制中发挥一定的作用。在慢性光损伤过程中,肥大细胞通过分泌基质金属蛋白酶和类胰蛋白酶等,参与光损伤中细胞外基质及基底膜的破坏;又通过分泌细胞因子如IL-10等,限制了小鼠皮肤慢性光损伤的病理过程。     

皮肤光老化组织学改变研究进展

皮肤光老化是不断累积的日光照射所致的一个连续性过程,是指长期的日光照射(主要是紫外线)导致皮肤衰老.在组织学方面,表皮变化主要是角质形成细胞、黑素细胞、朗格汉斯细胞,真皮变化主要是弹力纤维变性和胶原减少.其机制主要涉及免疫系统、细胞因子改变、基质金属蛋白酶生成增加、活性氧簇增加及DNA损伤等.概述并探讨皮肤光老化组织学变化及其相应的发生机制.     

皮肤衰老与微小RNA

皮肤衰老是机体衰老的表现之一,由于表皮和真皮内细胞结构、功能以及细胞外基质组分的变化所致.微小RNA是一组内源性非编码小分子RNA,研究表明,微小RNA与表皮、真皮的衰老以及紫外线诱导的皮肤衰老相关.在真皮中,微小RNA可以靶向作用于细胞外基质组分和细胞黏附分子,或调控细胞周期、端粒酶活性、细胞内信号通路及氧化应激等影响成纤维细胞的衰老.在表皮中,微小RNA可通过染色质重塑和p63途径参与角质形成细胞的衰老,或靶向作用于转化生长因子β依赖或非依赖的途径影响朗格汉斯细胞的衰老.而在紫外线诱导的皮肤衰老中,微小RNA在组蛋白甲基化、细胞周期调控因子以及转录激活因子等层面参与皮肤衰老过程.此外,有一些微小RNA如微小RNA 125b参与皮肤衰老的机制可能与表皮干细胞相关.     

Solar ultraviolet radiation induces biological alterations in human skin in vitro: relevance of a well-balanced UVA/UVB protection

Cutaneous damages such as sunburn, pigmentation, and photoaging are known to be induced by acute as well as repetitive sun exposure. Not only for basic research, but also for the design of the most efficient photoprotection, it is crucial to understand and identify the early biological events occurring after ultraviolet (UV) exposure. Reconstructed human skin models provide excellent and reliable in vitro tools to study the UV-induced alterations of the different skin cell types, keratinocytes, fibroblasts, and melanocytes in a dose- and time-dependent manner. Using different in vitro human skin models, the effects of UV light (UVB and UVA) were investigated. UVB-induced damages are essentially epidermal, with the typical sunburn cells and DNA lesions, whereas UVA radiation-induced damages are mostly located within the dermal compartment. Pigmentation can also be obtained after solar simulated radiation exposure of pigmented reconstructed skin model. Those models are also highly adequate to assess the potential of sunscreens to protect the skin from UV-associated damage, sunburn reaction, photoaging, and pigmentation. The results showed that an effective photoprotection is provided by broad-spectrum sunscreens with a potent absorption in both UVB and UVA ranges.     

Differential roles for Chk1 and FANCD2 in ATR-mediated signalling for psoralen photoactivation-induced senescence

Cellular senescence is a stress-inducible, naturally irreversible cell cycle arrest, which is likely linked with ageing. Premature ageing of the skin is a prominent side effect of psoralen photoactivation, which is used for the treatment of various skin disorders. Previously, we have shown that DNA interstrand crosslink formation by photoactivated psoralens induces a senescent phenotype in primary fibroblasts that is mediated by Ataxia telangiectasia-mutated and Rad3-related (ATR) kinase. Checkpoint kinase 1 (Chk1) initiates cell cycle checkpoints, and FANCD2 is known to be involved in DNA damage-induced S-phase arrest and crosslink repair. In this study, we examined a role for Chk1 and FANCD2 as downstream effectors of ATR in senescence signalling. We demonstrate that Chk1 and FANCD2 are long-lastingly activated after psoralen photoactivation. Separate and combined reduction in Chk1 and FANCD2 expression by small interfering RNA (siRNA) preceding irradiation partly prevented the initiation of the senescence-like phenotype, whereas siRNA (Chk1 and FANCD2) transfection of senesced fibroblasts released cells from growth arrest. We observed that Chk1 and FANCD2 signal equally and additively for senescence induction, while Chk1 is predominantly responsible for maintaining persistent cell cycle arrest. In conclusion, Chk1 and FANCD2 function downstream of ATR in a non-redundant manner for the establishment and maintenance of psoralen photoactivation-induced senescence.