不同皮肤老化小鼠模型的比较

目的比较亚急性衰老小鼠模型、光老化小鼠模型与青年小鼠、自然老化小鼠皮肤的异同点。方法分别采用D-半乳糖注射建立亚急性衰老小鼠模型,中波紫外线(ultraviolet B,UVB)照射建立光老化小鼠模型。从皮肤外观、组织学改变、生化指标、基质金属蛋白酶(matrix metalloproteinase,MMP)-1表达等多维度比较亚急性衰老小鼠模型、光老化小鼠模型与青年小鼠及自然老化小鼠的异同。结果亚急性衰老小鼠和自然老化小鼠外观上均表现为皮肤变薄伴细小皱纹,光老化小鼠皮肤明显增厚且皱纹粗大。在皮肤组织学改变方面,自然老化和亚急性衰老小鼠真皮和表皮厚度均降低,胶原纤维和弹力纤维均减少。光老化小鼠表皮和真皮厚度均增加,胶原纤维减少,弹力纤维增多、断裂。光老化小鼠和自然老化小鼠中Ⅲ型胶原比例增加,而亚急性老化小鼠中Ⅲ型胶原无明显变化。与青年小鼠比较,三种老化小鼠中超氧化物歧化酶(superoxide dismutase,SOD)活性、羟脯氨酸(hydroxyproline,Hyp)含量均降低,丙二醛(malondialdehyde,MDA)含量升高,MMP-1表达升高。结论亚急性衰老小鼠模型的皮肤外观和组织学指标接近自然老化小鼠;而光老化小鼠模型与前两者存在明显差异。三者皮肤老化的共同机制可能是ROS介导的MMPs(MMP-1)表达增高,从而导致细胞外基质的降解。本研究为皮肤老化研究中动物模型的选择提供了可靠的实验数据。     

全反式维A酸促进大鼠皮肤弹力纤维扭曲的修复

在探讨紫外线 (ＵＶ)照射引起的皱纹形成的机理时 ,结缔组织成分的三维结构是其中关键的问题之一。在有皱纹的人老化皮肤内 ,用扫描电镜 (ＳＥＭ)发现真皮弹力纤维超微结构改变。光老化皮肤的弹性下降和皱纹产生主要与弹力纤维三维线性的缺失有关。弹力纤维三维结构的研究为解释及预测光老化皮肤皱纹的产生及其程度提供了一种模型。外用全反式维Ａ酸 (ｔ-ＲＡ)可以改善日光照射引起的细小皱纹。该研究检测了外用ｔ-ＲＡ对大鼠皮肤中紫外线诱导的弹力纤维扭曲和皱纹消失的影响 ,以探讨弹力纤维在皱纹消除中的作用。材料与方法 :雄性ＳＤ大鼠 …     

光老化皮肤在皮肤磨削术后的临床改善与胶原I合成相关

皮肤磨削术是光化性角化病、光化性雀斑样痣和光老化性皱纹的成功治疗方法,但对其特殊的生物学机制了解甚少。有报告,皮肤磨削术,真皮乳头出现表皮下新生胶原带或“修复带”,可能对皮肤磨削术后的临床改善起作用。推测此带是新合成的Ⅰ型胶原。本文对此进行了进一步研究,10例光老化病人(年龄48～81岁,平均59岁),临床上均有严重的面部光老化,行面部皮肤磨削术直至真皮乳头水平。临床光老化严重程度以单盲方式对皮肤磨削前基线     

皮肤自然老化和光老化过程中弹性蛋白的变化及溶菌酶的重要作用

皮肤老化是一种累及多种皮肤成分的复杂生物学行为，它包含两个相互独立的过程：自然老化（亦称固有老化）和日光导致的光化性损伤。虽然它们在生物学、生物化学和分子机制方面截然不同，但都导致弹性纤维发生明显改变，表现为：光化性损伤皮肤出现弹性纤维成分的集聚，而非曝光皮肤老化则伴随弹性纤维数目的下降。二者均会导致弹性纤维功能障碍，使皮肤回弹力和弹性丧失而出现皮肤老化表现，如：皱纹、皮肤松弛等。光老化皮肤的组织学特征是真皮弹性组织变性（elastosis），表现为弹性纤维增多增粗，卷曲扭结，最终形成无定形颗粒状物质，但其具体机制尚不清楚。该研究检测皮肤自然老化和光老化过程中真皮弹性纤维的质变与量变，并探讨溶菌酶在其中的作用。     

植物提取物在光老化防治中的作用

目的同身体的其他器官一样,皮肤也随着时间而衰老。皮肤的老化包括固有老化和光老化。光老化的临床表现包括色素沉着、皮肤松弛、皱纹、毛细血管扩张、皮肤韧性改变甚至皮肤肿瘤;组织病理表现包括:成纤维细胞异常增多、光暴露部位慢性炎症改变、微循环及小血管壁改变。目前皮肤用药中含有数目众多的植物提取物,包括绿茶、菊类、橄榄油、大豆、橄榄、余甘子、蘑菇等,这些提取物在防治光老化的应用上将会越来越广。     

基质金属蛋白酶表达在皮肤光老化皱纹形成中的作用

目的 探讨皮肤光老化皱纹形成与真皮成纤维细胞基质金属蛋白酶(MMP)-1,MMP-3mRNA及其组织抑制剂(TIMP)-1表达的关系。方法 采用原位杂交和免疫组化的方法检测紫外线光化学疗法(PUVA)治疗期间及治疗后不同时间银屑病患者背部非皮损区真皮成纤维细胞MMP-1,MMP-3mRNA及TIMP-1蛋白的表达并定量分析。结果 在PUVA治疗期间、治疗后1~6个月及治疗后6个月以上的银屑病患者背部非皮损区真皮成纤维细胞均持续表达MMP-1、MMP-3mRNA,而TIMP-1蛋白仅在治疗期间一过性轻度表达。结论 PUVA治疗引起的皮肤光老化皱纹形成可能与真皮成纤维细胞基质金属蛋白酶及其组织抑制剂表达失衡密切相关。     

全反式维甲酸霜治疗老年斑痣

长期日晒引起的皮肤光老化中,以色素沉着及皱纹为著,而在黄色人种皮肤光老化中,色素沉着较皱纹出现早而明显。60岁以上的老人面部几乎都有老年斑痣。虽然本病不痛不痒,但影响容貌。本世纪六、七十年代国外开始用全反式维甲酸霜治疗皮肤光老化,证明有减轻色素沉着及皱纹等作用。     

无创性检测技术在皮肤光老化中的应用

光老化是指皮肤长期受紫外线(ultraviolet,UV)辐射所引起的皮肤老化.光老化皮肤主要表现为毛细血管扩张、粗糙干燥、松弛、皱纹加深、色素沉着,甚至可能出现各种良性或恶性肿瘤.大量研究对光老化皮肤的变化从各个方面进行描述和评估,如临床肉眼评估、组织病理及免疫组织化学检查等.随着科技的发展,无创检测技术在皮肤光老化...     

海洋生物提取物中抗皮肤光老化活性成分的研究进展

 海洋生物是海洋资源的重要组成部分,具有抗菌、抗氧化、抗炎及光保护等生物活性,在医用护肤品和药物的生产中有重要的贡献。长期紫外线照射是皮肤外源性老化的主要原因。紫外线照射可损伤表皮角质形成细胞和真皮成纤维细胞,引起皮肤萎缩、皱纹及皮肤肿瘤等。海洋生物中有众多光保护物质,包括类菌孢素氨基酸、硫酸多糖、类胡萝卜素和多酚类物质等,这些物质在皮肤护理、化妆品和医药产品中有很大的开发潜力。本文综述了近年来海洋生物中的光保护物质及其在皮肤光老化中的应用进展。     

局灶性光热作用技术治疗光老化研究进展

光老化主要表现为皮肤皱纹增加、角质增厚、微循环变化以及色素异常改变.局灶性光热作用技术是激光治疗光老化的新技术.该技术主要有非气化型局灶性光热作用技术和气化型局灶性光热作用技术,其中气化型光热作用技术主要有点阵CO_2技术和点阵铒激光技术.从治疗的组织学改变、临床应用评价和不良反应三方面概述非气化型局灶性光热作用技术、点阵CO_2激光技术和点阵铒激光技术治疗皮肤光老化的研究进展.     

Clinical efficacy of adapalene (differin(®)) 0.3% gel in Chilean women with cutaneous photoaging

Skin photoaging is a concern for many patients today, and it is important for dermatologists to evaluate new therapeutic approaches. This 6-month open-label study evaluated the effectiveness and safety of adapalene 0.3% gel in 40 Latin American women with signs of facial photoaging. Assessments at baseline, week 12, and week 24 included clinical severity grading, measurement of transepidermal water loss, hydration, and elasticity (Cutometer MPA 850?), evaluation of general skin tone and number of wrinkles (VISIA(?) Complexion Analysis System), and ultrasonography to measure changes in skin thickness. There were significant improvements in clinical grading of wrinkles (p < 0.01) with a reduction in mean severity score of 40% in forehead wrinkles, 52% in periorbital wrinkles, and 29% in perioral wrinkles. Melanin, transepidermal water loss, and hydration were improved, as were general skin tone and the number of wrinkles (p < 0.05). Measurement of skin thickness showed a non-significant improvement in the epidermis and dermis and a significant decrease of the elastosis band (11.6% at week 12 and 15.1% at week 24). Adapalene was well tolerated overall, although three patients discontinued the study due to skin irritation in the first month. We conclude that adapalene 0.3% gel is a new safe and effective approach to photoaging.     

Correlation of skin phototype with facial wrinkle formation

Facial wrinkle formation is a representative sign of photoaging. Skin can be divided into different skin phototypes (SPTs) depending on its sensitivity to solar radiation. We have determined the relationship between SPTs and deep and fine wrinkle scores on the faces of 230 Japanese subjects. This group was chosen because it is relatively easy to quantify acute and chronic sun damage in Japanese individuals. SPT in the Japanese subjects was classified into one of four groups, SPT-I to -IV according to Fitzpatrick's classification method. The subjects were further classified into indoor or outdoor workers. After photographing the outer canthus, deep and fine wrinkles were discriminated visually and scored from 1–11 and from 1–9, respectively. UV light was used as a photographic light source for clear depiction of the fine wrinkles. Higher scores were recorded for deep wrinkles in individuals with SPT-I, who are more sensitive to sunlight than those with SPT-III or IV, who are more tolerant to sunlight. However, the same tendency did not seem to be apparent for fine wrinkle scores. A high incidence of SPT-IV was seen in outdoor workers. Early detection of SPT-I in individuals who are sensitive to sunlight, may help to predict and prevent photoaging of deep wrinkles. Sensitivity to sunlight may play a part in determining an individual's choice of working environment.     

Objective and subjective clinical effects of a Nd:YAG 532-nm frequency-doubled long-pulsed diode pumped laser system on photoaging of the face: a retrospective study on color signs, texture and rhytids.

BACKGROUND: Pulsed 532-nm lasers have been widely used in the treatment of vascular and pigmented conditions of aged skin. In addition to lesion clearance, many patients report color and texture improvements to the skin. These improvements are often difficult to appreciate from photographic analysis alone, but are significant to the patient's impression of treatment success. OBJECTIVE: To grade and compare objective and subjective results of treatments with a 532-nm frequency-doubled pulsed Nd:YAG laser using criteria of skin color, skin texture, and wrinkles based on a blinded retrospective analysis of photographs compared with results from patient questionnaires. METHODS: Clinical before and after pictures from 20 patients (skin types I-IV) treated for diffuse vascular and pigmented lesions were selected for evaluation. A blinded grading was performed using criteria of skin color, skin texture, and wrinkles. Patients were asked by questionnaire to also grade improvement using the same criteria. The results of the blinded and patient grading were reported and compared using a chi-squared analysis. RESULTS: Clinical improvements recorded by blinded photographic evaluation and patient evaluation agreed with no statistically significant differences. Both the blinded observers and patients recorded remarkable improvement in the color signs of photoaging, slight to moderate improvement in skin texture and fine wrinkles, and negligible improvement of medium depth and deep wrinkles. CONCLUSION: The 532-nm pulsed laser is a safe and effective device for the treatment of the visible signs of photoaging of skin types I-III. In addition to improvements in color defects, objectively and subjectively significant improvements in texture and fine wrinkles can be expected. Little to no improvement in medium to deep wrinkles can be anticipated.     

Relationships between changes in mechanical properties of the skin, wrinkling, and destruction of dermal collagen fiber bundles caused by photoaging

BACKGROUND/PURPOSE: Long-term exposure to ultraviolet (UV) radiation induces various cutaneous changes that differ from those because of physiological aging, including structural destruction of dermal collagen fiber bundles (DCFBs), which comprise the major component of the dermis. Wrinkling, a representative change in skin surface associated with photoaging, is often seen at the corners of the eyes and in the space between the eyebrows. These are locations where the skin contracts repeatedly and routinely. Lowered resiliency to skin contraction induced by marked structural changes in DCFBs may represent one cause of photo-induced wrinkles. Using animal models of photoaging, changes in mechanical properties of the skin caused by UV irradiation were measured, and relationships between UV-induced changes were analyzed. METHODS: Animal models of photoaging were prepared by irradiating hairless mice with UVB light. Dorsal skin surface replicas of animals were taken using silicon rubber, and volume of wrinkles was calculated using an image analyzer. Stress of the skin against horizontal contraction was measured using a new device called the Resiliometer. Three-dimensional organization of dermal collagen structures in skin samples collected from the back of each animal was observed under scanning electron microscopy, and compactness of DCFBs was assessed from electron micrography. RESULTS: With time and therefore increasing UV dose, deep wrinkles formed on the backs of mice. Volume of wrinkles peaked at 8 weeks. All parameters obtained from Resiliometer measurements were increased by irradiation. DCFB structure was degraded in a radiation dose-dependent manner. DCFB grading was significantly correlated with each Resiliometer parameter. Significant correlations were also observed between each Resiliometer parameter and volume of wrinkles. CONCLUSION: Stress of the skin against horizontal contraction obtained using the Resiliometer changes following UV irradiation, correlating with photo-induced wrinkling and destruction of DCFBs. These results support the hypothesis that changed force of restitution to skin contraction induced by marked structural changes in DCFBs represents one cause of photo-induced wrinkles. The resiliometric parameter may offer a good indicator for monitoring the condition of DCFB structure, as changes in these would induce failure in restitution to skin contraction, leading to wrinkling.     

Skin aging and dry skin

Skin aging appears to be the result of both scheduled and continuous "wear and tear" processes that damage cellular DNA and proteins. Two types of aging, chronological skin aging and photoaging, have distinct clinical and histological features. Chronological skin aging is a universal and inevitable process characterized primarily by physiologic alterations in skin function. In this case, keratinocytes are unable to properly terminally differentiate to form a functional stratum corneum, and the rate of formation of neutral lipids that contribute to the barrier function slows, causing dry, pale skin with fine wrinkles. In contrast, photoaging results from the UVR of sunlight and the damage thus becomes apparent in sun-exposed skin. Characteristics of this aging type are dry and sallow skin displaying fine wrinkles as well as deep furrows, resulting from the disorganization of epidermal and dermal components associated with elastosis and heliodermatitis. Understanding of the functions of the skin and the basic principles of moisturizer use and application is important for the prevention of skin aging. Successful treatment of dry skin with appropriate skin care products gives the impression of eternal youth.     

Topical Retinoids: Therapeutic Mechanisms in the Treatment of Photodamaged Skin

Retinoids are a group of substances comprising vitamin A and its natural and synthetic derivatives. Retinoids were first used in dermatology in 1943 by Straumfjord for acne vulgaris. Since that time, retinoids have been utilized in the management and treatment of various skin conditions, including photoaging. Photodamage of the skin occurs as a consequence of cumulative exposure to solar ultraviolet radiation (UVR) and is characterized by deep wrinkles, easy bruising, inelasticity, mottled pigmentation, roughness, and telangiectasias. The mechanism of UVR-induced photodamage is multifactorial. Retinoids have demonstrated efficacy in the treatment of photoaged skin. Indeed, understanding the pathophysiology of photoaging and the molecular mechanism of retinoids can not only provide insight into the effects retinoids can exert in treating photoaging but also provide the rationale for their use in the treatment of other dermatologic diseases.     

Cutaneous photodamage in Koreans: influence of sex, sun exposure, smoking, and skin color

BACKGROUND: Severe wrinkles and pigmentary changes of the exposed skin indicate substantial damage due to UV radiation. Many investigators believe that the principal manifestation of photodamage in Asians is pigmentary change rather than wrinkles. However, to our knowledge, no well-designed study has investigated the characteristics of cutaneous photodamage in Asian skin. OBJECTIVE: To access the severity of wrinkles and dyspigmentation in Koreans exposed to sun and who smoked. METHODS: We developed new photographic scales for grading wrinkles and dyspigmentation in 407 Koreans to assess the severity of the wrinkles and dyspigmentation. We interviewed subjects to determine cumulative sun exposure and smoking history, and measured the skin color of individual subjects. RESULTS: Our photographic scales provided a reliable evaluation of photodamage severity in Koreans. The pattern of wrinkling in both sexes is similar, but women tended to have more severe wrinkles (prevalence odds ratio, 3.7). However, the pattern of dyspigmentation differed between the sexes. Seborrheic keratosis is the major pigmentary lesion in men, whereas hyperpigmented macules are the prominent features in women. Cigarette smoking is an independent risk factor for wrinkles, but not for dyspigmentation, in Koreans, and causes additive detrimental effects to wrinkles induced by aging and sun exposure. The constitutive skin color did not show any correlation with wrinkles or dyspigmentation. However, facultative pigmentation (sun exposure index) may reflect lifetime sun exposure, and it shows a good correlation with wrinkles in Koreans. CONCLUSION: Wrinkling is a major feature of photoaging in Koreans, as are pigmentary changes; smoking, sun exposure, and female sex are independent risk factors for wrinkles.     

Objective and subjective clinical effects of a Nd:YAG 532‐nm frequency‐doubled long‐pulsed diode pumped laser system on photoaging of the face: A retrospective study on color signs,texture and rhytids

BACKGROUND: Pulsed 532‐nm lasers have been widely used in the treatment of vascular and pigmented conditions of aged skin. In addition to lesion clearance, many patients report color and texture improvements to the skin. These improvements are often difficult to appreciate from photographic analysis alone, but are significant to the patient's impression of treatment success. OBJECTIVE: To grade and compare objective and subjective results of treatments with a 532‐nm frequency‐doubled pulsed Nd:YAG laser using criteria of skin color, skin texture, and wrinkles based on a blinded retrospective analysis of photographs compared with results from patient questionnaires. METHODS: Clinical before and after pictures from 20 patients (skin types I–IV) treated for diffuse vascular and pigmented lesions were selected for evaluation. A blinded grading was performed using criteria of skin color, skin texture, and wrinkles. Patients were asked by questionnaire to also grade improvement using the same criteria. The results of the blinded and patient grading were reported and compared using a chi‐squared analysis. RESULTS: Clinical improvements recorded by blinded photographic evaluation and patient evaluation agreed with no statistically significant differences. Both the blinded observers and patients recorded remarkable improvement in the color signs of photoaging, slight to moderate improvement in skin texture and fine wrinkles, and negligible improvement of medium depth and deep wrinkles. CONCLUSION: The 532‐nm pulsed laser is a safe and effective device for the treatment of the visible signs of photoaging of skin types I–III. In addition to improvements in color defects, objectively and subjectively significant improvements in texture and fine wrinkles can be expected. Little to no improvement in medium to deep wrinkles can be anticipated.     

The roles of cytokines in photoaging

Photoaging comprises characteristic changes in appearance and function of the skin as a result of repeated sun exposure rather than to passage of time alone. Clinically, wrinkles, laxity, coarseness, mottled pigmentation, lentigenes, teleangiectasia and purpura characterize photoaging. Photoaging is also characterized by atrophy, fibrotic depigmented areas termed pseudoscars, and ultimately premalignant and malignant neoplasms on sun exposed areas. These features are the result of ultraviolet radiation (UVR) in the sunlight. UVR stimulates and activates various cells and tissues to produce and release cytokines that may play a significant role in the process of photoaging. However, cytokines are the major orchestrators of the host defense processes and are involved in response to exogenous and endogenous insults, and repair and restore homeostasis. Therefore, cytokines may be beneficial in the course of photoaging. Considering the complex cytokine network in the skin, focus will be taken on several subjects that have seen major changes during the last few years. I will first outline our knowledge of cytokines in the skin together with their functions, then review our knowledge of the involvement of cytokines in photoaging, and finally summarize the defense system related to cytokines.