成体干细胞可能对冠心病和自身免疫性疾病有益

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Adult Stem Cells May Be Beneficial For Certain Cardiovascular Disorders And Autoimmune Diseases

ScienceDaily (Feb. 28, 2008) — A review of previously published research suggests that stem cells harvested from an adult's blood or marrow may provide treatment benefit to select patients for some autoimmune diseases and cardiovascular disorders.

In broad terms, there are two types of stem cells, embryonic stem cells and adult stem cells. Human embryonic stem cells are isolated from a 4- to 5-day-old postfertilization blastocyst (an early form in the development of an embryo). Adult stem cells are located in tissues throughout the body and function as a reservoir to replace damaged or aging cells.

Stem cell therapy is rapidly developing and shows great promise, \"but clinical application has lagged due to ethical concerns or difficulties in harvesting or safely and efficiently expanding sufficient quantities. In contrast, clinical indications for blood-derived (from peripheral or umbilical cord blood) and bone marrow-derived stem cells, which can be easily and safely harvested, are rapidly increasing,\" the authors write.

Richard K. Burt, M.D., of the Northwestern University Feinberg School of Medicine, Chicago, and colleagues conducted a review of articles regarding clinical indications and outcomes for use of blood- and bone marrow-derived stem cells. A search of databases identified 323 reports that were examined for feasibility and toxicity, and 69 that were evaluated for outcomes. These studies were published between January 1997 and December 2007.

For autoimmune diseases, 26 reports representing 854 patients reported treatment-related mortality of less than one percent (2/220 patients) for nonmyeloablative (not causing bone marrow suppression), less than two percent (3/197) for dose-reduced myeloablative, and 13 percent (13/100) for intense myeloablative regimens, i.e., those including total body irradiation or high-dose busulfan (a drug used in the treatment of some types of chronic leukemia).

\"While all trials performed during the inflammatory stage of autoimmune disease suggested that transplantation of hematopoietic [formation of blood or blood cells] stem cells (HSCs) may have a potent disease-remitting effect, remission duration remains unclear, and no randomized trials have been published,\" the researchers write.

For reports involving cardiovascular diseases, including 17 reports involving 1,002 heart attack patients, 16 reports involving 493 patients with chronic coronary artery disease, and three meta-analyses, the evidence suggested that stem cell transplantation performed in patients with coronary artery disease may contribute to modest improvement in cardiac function.

\"Stem cells harvested from blood or marrow, whether administered as purified HSCs or mesenchymal [cells that develop into connective tissue, blood vessels and lymphatic tissue] stem cells or as an unmanipulated or unpurified product can, under appropriate conditions in select patients, provide disease-ameliorating effects in some autoimmune diseases and cardiovascular disorders. Clinical trials are needed to determine the most appropriate cell type, dose, method, timing of delivery, and adverse effects of adult HSCs for these and other nonmalignant disorders,\" the authors conclude.
成体干细胞可能对冠心病和自身免疫性疾病有益。科技日报（2008-2-28）----一综述认为来源与成人血液或骨髓的干细胞对自身免疫性疾病和冠心病的治疗有益。大体而言有两种类型的干细胞----胚胎干细胞和成体干细胞。人类胚胎干细胞为从4—5天大小的囊胚（胚胎的早期）分离而得。成体干细胞则存在于机体各个组织，像一个储存期取代损伤或衰老的细胞。干细胞治疗发展迅速，潜力巨大，“但因为伦理学及难以获取或安全有效扩增到足够数量等原因使得临床应用落后。相反，临床适应症增长迅速，因为外周血干细胞（来源于外周血或脐血）和骨髓干细胞可简单安全提取。”Richard K. Burt, M.D（西北大学Feinberg医学院，芝加哥）和其同事完成了关于使用外周血干细胞或骨髓干细胞治疗的临床适应症和疗效的综述。其中323份报道是关于可行性和毒性，69是评价疗效。这些报道出版业1997年1月至2007年12月间。对于自身免疫性疾病，26份报道包括854名患者中，非清髓治疗相关死亡率少于1%（2/220），剂量减少清髓少于2%（3/197），激烈清髓为13%（13/100），如包括全身照射或大剂量白消安（一种用于一些慢性白血病治疗的药物）。 “在自身免疫性疾病的炎性期所有治疗中，根据疗效造血干细胞移植可能有缓解疾病的潜力，缓解持续时间目前仍不清楚，且目前没有随机治疗结果发表。”对于冠心病，包括17份报道的1002名心脏病发作患者中，16份报道的493名慢性冠心病患者，三项meta分析，结果表明干细胞移植治疗冠心病患者可能会改善心功能。 “外周血或骨髓提取的干细胞，无论是作为纯化的造血干细胞或间充质细胞（可分化为结缔组织、血管或淋巴组织）输注，或作为非处理或非纯化的产品，在适当的条件为合适的病人，对其自身免疫性疾病或心血管病症提供缓解功能。成体干细胞治疗这些或其他非恶性疾病需要临床试验来确定最合适的细胞类型、剂量、方法、delivery时间和副作用。”
http://www.sciencedaily.com/releases/2008/02/080226162859.htm

附注:
成体干细胞是一类成熟较慢但能自我维持增殖的未分化的细胞，这种细胞存在于各种组织的特定位置上，一旦需要, 这些细胞便可按发育途径, 先进行细胞分裂, 然后经过分化产生出另外一群具有有限分裂能力的细胞群。
成体干细胞的发育等级较低，是多能或单能干细胞。造血干细胞(hematopoietic stem cell，HSC)和骨髓间质干细胞(mesenhymal stem cell)是熟知的成体干细胞。
这种细胞的分化功能被局限在只能分化成具有某种功能或某几种功能的体细胞上。成年动物体内的干细胞即成体干细胞通常只能发展成特定种类的体细胞，比如造血干细胞发展成血液细胞。
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