恶性黑素瘤与黑素干细胞

恶性黑素瘤是高度转移性肿瘤,对传统的治疗抵抗,黑素瘤的发生涉及遗传和环境因素。大多数黑素瘤为原发性,但部分黑素瘤从黑素细胞痣发展而来。以往认为,长期暴露于紫外线、皮肤黑素细胞逐渐积累致癌基因、肿瘤抑制基因发生突变导致了黑素细胞的增殖,并获得侵袭性和转移的能力,成为黑素瘤。另有假说认为,黑素瘤起源于毛囊外真皮黑素干细胞,紫外线诱导的突变可能会改变正常黑素干细胞自我更新、扩展和分化的过程,导致黑素瘤的形成。深入了解黑素瘤的发生机制,有利于寻求更好的治疗方案。     

干细胞在皮肤病中的应用

干细胞是存在于所有多细胞组织中,具有自我更新、增殖分化潜能的一种未分化细胞。干细胞的种类随研究的深入逐渐增多。干细胞治疗相关疾病的具体机制多数未明。目前在皮肤科领域,干细胞研究主要集中于皮肤损伤修复与组织工程学再生以及自身免疫相关性疾病、遗传性皮肤病、皮肤自然衰老与光老化、皮肤肿瘤等疾病治疗方面。干细胞应用的适应证随着研究的深入逐渐增加,特别在目前传统治疗方法棘手的自身免疫疾病、遗传性皮肤病、皮肤肿瘤等领域显示出优势。     

肿瘤干细胞与皮肤黑素瘤

近年的许多研究显示,先天性黑素细胞痣、蓝痣、细胞性蓝痣、普通型色素痣以及黑斑、雀斑等色素性病变并无发生黑素瘤的显著危险性,临床所见的黑素瘤多数不是发生在非典型色素痣,更多的是发生在以前外观正常的皮肤1.随着对肿瘤干细胞深入的研究,一些证据提示黑素瘤可能起源于干细胞.这种新的认识,将影响对黑素瘤的诊断和治疗.     

干细胞移植治疗与重要脏器功能的修复与重建

干细胞（stem cells, SCs）是具有自我更新、高度增殖和多向分化潜能的细胞，通过分裂维持自身细胞群的大小，同时又可分化成为各种不同的组织细胞，从而构成机体各种复杂的组织器官[1]。根据干细胞所处的发育阶段分为：胚胎干细胞（embryonic stem cells，ESCs）；成体干细胞（somatic stem cells，SSCs）。人体几乎所有组织都存在经历相当程度的分化SSCs，但在特定条件下，一种组织的SSCs可以“横向分化”成其他组织的功能细胞，如间充质干细胞（mesenchymal stem cells, MSCs）可以分化成神经、肌肉、软骨和骨等多种细胞[2]。MSCs属于中胚层的一类多能干细胞，主要存在于结缔组织和器官间质中，以骨髓组织中含量最为丰富，且主要来源于骨髓，又称为骨髓间充质干细胞（bone marrow mesenchymal stem cells, BMSCs）。Friedenstein等[3]于1976年首先分离BMSCs，研究证实BMSCs具有强大的增殖能力和多向分化潜能、免疫调节及免疫重建功能，并且来源方便，易于分离、培养、扩增和纯化，经多次传代扩增后仍具有干细胞特性，不存在免疫排斥。因此，BMSCs可能成为细胞移植和基因治疗的理想材料，目前国内外正在探索用于神经系统疾病及多领域多学科难治性疾病的治疗，并已取得了重大突破性进展[4-6]。我国MSCs的研究发展极为迅速，某些核心技术已占国际领先地位，2001年国家批准建立“国家干细胞工程产品产业化基地”，2002年4月在天津建立“国家干细胞工程技术研究中心”。     

毛囊间充质干细胞的研究进展

 毛囊间充质干细胞（HFMSCs）是一类具有自我再生能力、高度增殖潜能、可多向分化且来源丰富的慢周期标记滞留细胞,可促进表皮、毛囊和皮脂腺再生。得益于其来源丰富、易获得、可于体外扩增、无需基因操作、不会形成肿瘤和无伦理限制等特点,毛囊间充质干细胞在再生医学中具有重要优势。Wnt、Shh、Notch和BMP等信号通路之间的协同和拮抗作用在干细胞稳态调节、表皮发育和毛囊再生过程中发挥至关重要的作用,这些途径的失调可能导致毛发脱落或者肿瘤的发生。本文综述毛囊间充质干细胞的分类及其特异性生物标记物、毛囊间充质干细胞的活化以及影响毛发再生的生物分子途径,为毛发疾病的治疗提供新的线索和靶点。     

毛囊干细胞研究进展

毛囊是一个周期性自我更新的皮肤附属器，干细胞周期性的增殖和分化决定毛囊的生长特性。毛囊有两个干细胞群，一个位于毛囊的隆突部，另一个位于毛囊的下三分之一近毛球部。它们有不同的命运和功能．分化形成毛囊的不同部分。就毛囊周期主要细胞的增殖、分化、迁移等过程进行综述，分析毛囊周期的形成机制。     

表皮干细胞与表皮肿瘤

表皮干细胞具有无限增殖及多向分化的特性，其子代细胞可以形成角质形成细胞、毛囊、皮脂腺的分化细胞。肿瘤一般起源于单个发生癌性突变的细胞，表皮干细胞很可能是各种类型表皮肿瘤发生的主要靶细胞，分化细胞则能通过影响肿瘤干细胞的克隆扩增，对肿瘤的发生起重要作用。     

表皮干细胞的研究进展

干细胞是一类具有高度增殖潜能和无限自我更新能力的细胞亚群。角质形成细胞干细胞主要存在于毛囊隆突部，也见于毛囊间表皮网嵴的底部，其特征为慢周期及高度的增殖潜能，它能表达某些整合素亚单位，并可与细胞外基质发生快速粘连，据此特性可将其分离纯化。角质形成细胞干细胞不仅在表皮及其附属器的组织发生学、银屑病的发病机理中具有重要作用，也是肿瘤发生及基因治疗的重要靶细胞。     

兔骨髓间充质干细胞低氧培养及基本性质研究

目的探讨体外低氧浓度培养条件对于新西兰大白兔骨髓问充质干细胞（bone marrow mesenchymal stem cells，BM—MSCs）增殖、分泌等特性的影响。方法将细胞分为低氧浓度培养组及对照组，分别检测其细胞表面标志物表达、分化能力、生长曲线、克隆形成能力，并使用ELISA法检测两组胶质细胞源性神经营养因子（GDNF）分泌量的区别。结果低氧浓度培养组细胞在表面标志物表达及分化能力上均与对照组无明显区别，而增殖能力及克隆形成能力较对照组明显增强，经ELISA检测，低氧浓度培养条件下的细胞GDNF的分泌量更高。结论低氧浓度的培养条件有利于BM—MSCs增殖及分泌能力增强，适宜用于BM—MSCs的扩增。     

树突状细胞疫苗治疗恶性黑素瘤的作用

近年恶性黑素瘤发病率不断增高，而且缺乏理想的治疗方法。树突状细胞疫苗是近年发展起来的一项新的免疫治疗技术。它是利用恶性黑素瘤细胞或恶性黑素瘤的抗原物质来诱导机体产生特异性细胞免疫和体液免疫应答，增强机体的抗癌能力，阻止肿瘤的生长、扩散和复发，从而达到治疗肿瘤的目的。目前抗恶性黑素瘤免疫治疗已进入Ⅰ～Ⅲ期临床研究，疗效可观，但仍待进一步研究以推广使用。     

Stem cell and skin rejuvenation

Stem cell-based therapies have been widely used for their abilities to repair and regenerate different types of tissues and organs in cosmetic and plastic surgeries. It involves the clinical application of different types of stem cells. Different stem cells have been reported to be applicable in different areas of cosmetic surgeries like face lipoatrophy, skin rejuvenation, breast enhancement, and body contouring. However, adipose-derived stem cells remain the most widely used by cosmetic surgeons as they have the potential and capability to differentiate into mesenchymal, ectodermal, and endodermal lineages and are easily accessible to harvest. The purpose of this review is to summarize available applications of stem in cosmetic and plastic surgeries.     

Stem cells and the skin

Stem cells live long lives, renew themselves, and differentiate into more mature, less potent, specialized cells, such as epidermal keratinocytes and dermal fibroblasts. Stem cells can be embryonic, if derived from an embryo, or adult/somatic if derived from postembryonic tissue. By producing new skin cells, stem cell division and differentiation can potentially rejuvenate skin and restore hair. To reproduce, stem cells can undergo symmetric nondifferentiative or differentiative divisions, or asymmetric differentiative divisions. Asymmetric divisions reproduce the stem cell and provide a more differentiated, but less potent transient amplifying cell. Divisions and differentiation of transient amplifying cells regenerate tissues by producing cells of a specific lineage, for example, keratinocytes. Epidermal stem cells lie in niches in the interfollicular epidermis, sebaceous gland, and in the bulge regions of hair follicles. These epidermal stem cells renew the epidermis, the sebaceous glands, and hair follicles after mature cells die. Dermal stem cells lie in the hair papillae, around pericytes, and elsewhere among other dermal cells. These form pericytes, myoblasts, fibroblasts, chondrocytes, and other specialized dermal cells. Along with other signaling pathways, the Wnt signaling pathway controls stem cell fate. Wnt signals enlist two functionally and chemically different gene coactivators to direct the time and type of replicative divisions. Stem cells may help to heal wounds, repair damaged tissues, regenerate aged skin, and reinvigorate growth of skin, hair, nails, and mucous membranes.     

Stem cells in the epidermis

The epidermis consists of three actively proliferating units, the interfollicular epidermis, the hair follicle, and the sebaceous gland. Stem cells in the epidermis have the capacity to produce all three of these units. The fate of the epidermal stem cells and some of their progeny can be altered, dependent on the environment in which they reside and the genes they express. In this review, we describe the major experiments that have contributed to the understanding of the epidermal stem cells and the control of their fate.     

Stem cells in dermatology

Preclinical and clinical research have shown that stem cell therapy could be a promising therapeutic option for many diseases in which current medical treatments do not achieve satisfying results or cure. This article describes stem cells sources and their therapeutic applications in dermatology today.     

Stem cells in cutaneous wound healing

Treatment of chronic wounds remains difficult, in spite of better understanding of pathophysiologic principles and greater adherence to recognized standards of care. Even with recent advances stemming from breakthroughs in recombinant growth factors and bioengineered skin, up to almost 50% of chronic wounds that have been present for more than a year remain resistant to treatment. Because of these realities, there is excitement in the use of stem cells to offset impaired healing. Early data appear encouraging, but much work remains to be done. Although pilot studies suggest that multipotent adult stem cells can accelerate wound repair or even reconstitute the wound bed, the answers will need to come from randomized clinical trials. Thus far, considerable focus has been placed on bone marrow-derived mesenchymal stem cells, and there are now promising approaches for introducing them into the wound. It might turn out, however, that other types of stem cells will be more effective, including those derived from hair follicles or, perhaps, subsets of bone marrow-derived cultured cells. Still, proper wound care and adherence to basic principles cannot be bypassed, even by the most sophisticated approaches.     

干细胞治疗斑秃的研究进展

【摘要】 目前认为，斑秃是由于毛囊免疫赦免被破坏导致。干细胞具有免疫调节功能，可分泌多种细胞因子，促进毛囊免疫赦免。干细胞治疗，尤其是脐带和脂肪来源的干细胞相关疗法已应用于多种脱发的临床前和临床研究，为难治性斑秃提供了治疗新途径。