间充质干细胞治疗年龄相关性黄斑变性研究现状及其局限性

年龄相关性黄斑变性(AMD)是老年人群主要的致盲眼病,主要影响患者的视网膜色素上皮细胞(RPE)及光感受器,导致患者中心视力进行性丧失。AMD分为干性AMD和湿性AMD 2种类型,目前临床上对于AMD的治疗主要针对湿性AMD伴发的脉络膜新生血管(CNV),而对于干性AMD尚无有效的治疗方法。AMD常见的治疗方法主要包括光动力疗法(PDT)和玻璃体腔注射抗血管内皮生长因子(VEGF)药物治疗,此外还有激光治疗、放射疗法和手术治疗等,然而现阶段的临床治疗均无法根除病因,且部分患者对治疗反应差,因此人们开始探索新的AMD治疗方法。其中,间充质干细胞(MSCs)治疗具有自我更新和多向分化潜能、低免疫原性和取材方便、伦理道德方面约束较少的特点,展现出了广阔的治疗前景。目前,国内外相继开展了许多利用MSCs治疗AMD的研究,成果颇丰。本文阐述了AMD的分型和治疗现状及其局限性,并对近年来国内外针对MSCs治疗AMD的研究成果进行综述。

自体角膜缘干细胞移植联合丝裂霉素C治疗复发性翼状胬肉90眼

目的观察翼状胬肉切除自体角膜缘干细胞移植联合丝裂霉素C局部浸润治疗复发性翼状胬肉的效果。方法复发性翼状胬肉89例90眼患者均在手术显微镜下切除翼状胬肉并做自体角膜缘干细胞移植联合局部应用丝裂霉素C，术后随访6个月-24个月。结果患者89例90眼，术后2例复发，术后再次复发率为2．22％，手术成功率为97．78％。早期浅层点状角膜炎5眼（5．55％），未做特殊处理，5～7d痊愈。结论常规切除胬肉联合自体角膜缘干细胞移植术中应用丝裂霉素C治疗舅发性翌状胬肉的效果满音．

电针联合脂肪源性干细胞移植对大鼠脑缺血/再灌注损伤后海马区CXCL2及受体CXCR2表达的影响

目的:探讨电针联合脂肪源性干细胞(adipose-derivedstem cell,ADSC)移植对大鼠缺血/再灌注损伤后海马区CXC趋化因子2(CXC chemokine ligand 2,CXCL2)及受体(CXC chemokine receptor 2,CXCR2)表达的影响。方法:采用线栓法复制大鼠大脑中动脉缺血再灌注模型,将动物随机分为正常对照组、模型对照组、电针组、ADSC移植组和电针+ADSC组5组。应用NSS法行神经功能损害评分,采用蛋白质印迹法和实时荧光定量PCR分别检测海马区CXCL2和CXCR2蛋白及其mRNA的表达水平。结果:电针+ADSC组海马区PKH-26标记的细胞个数高于ADSC组,差别有统计学意义(P<0.05)。电针+ADSC组NSS评分低于单独治疗组(P<0.05)。与模型对照组对比,电针+ADSC组和电针组的CXCL2和CXCR2蛋白和mRNA表达水平均下降,差别有统计学意义(P<0.05)。结论:电针联合脂肪源性干细胞移植促进脑缺血大鼠神经功能恢复作用优于单独治疗组,其机制可能是电针通过下调炎症递质CXCL2和CXCR2的表达抑制炎性反应,从而促进移植的ADSC迁移和存活。

自体角膜缘干细胞移植治疗翼状胬肉60例

目的观察自体角膜缘干细胞移植对翼状胬肉疗效的影响。方法在手术显微镜下,采用自体角膜缘干细胞移植治疗初发性和复发性翼状胬肉60例(65眼),术后随访观察6个月～4年。结果54例(58眼)痊愈,6例(7眼)复发,术后复发率为12.07%。结论自体角膜缘干细胞移植治疗翼状胬肉,有助于角膜、结膜的重建,阻止新生血管及结膜上皮侵入角膜,有效抑制了胬肉的复发,是治疗翼状胬肉的理想手术方法。

人羊膜移植联合自体角膜缘干细胞移植治疗中重度眼部碱烧伤

目的 观察人羊膜移植联合自角膜缘干细胞移植治疗中重度眼部碱烧伤的临床效果。方法 对 8眼中重度眼部碱烧伤早期进行人羊膜移植联合自体角膜缘干细胞移植。结果 8眼中 ,7眼眼表面重建成功 ,4眼角膜透明 ,3眼角膜半透明 ,仅 1眼发生轻度睑球粘连。结论 人羊膜移植联合自体角膜缘干细胞移植治疗中重度眼部碱烧伤。对于重建眼表面 ,提高视功能 ,早期应用疗效较好。

极小胚胎样干细胞的研究现状和眼科临床意义

极小胚胎样干细胞(very small embryonic-like stem cells,VSELs)是美国路易斯维尔大学Kucia研究小组从小鼠骨髓和人脐带血中分离出一种具有类似胚胎干细胞生物特性的多潜能成体干细胞。与胚胎干细胞相似的外表——细胞形态及表面标志、以及相似的内在——多分化潜能决定了VSELs一出现就被细胞替代疗法视为最有潜力的种子细胞,本文就VSELs的研究历程及在眼科干细胞治疗视网膜退行性疾病中的临床意义作一综述。

促肝细胞生长素联合乳果糖及新鲜血浆治疗重症肝炎20例

目的:观察促肝细胞生长素联合乳果糖及新鲜血浆治疗重症肝炎的临床疗效。方法:40例患者分为两组,对照组20例,治疗组20例。两组患者均采用基础疗法,治疗组在此基础上加用促肝细胞生长素(HGF)、乳果糖及新鲜血浆。比较两组患者治疗前后的综合疗效。结果:治疗组总有效16例,无效4例,总有效率为80%;对照组总有效8例,无效12例,总有效率40%。两组有效率比较,P<0.05。结论:促肝细胞生长素联合乳果糖及新鲜血浆治疗重症肝炎安全有效,可明显改善患者的临床症状,降低病死率,值得推广。

Nestin in gastrointestinal and other cancers: Effects on cells and tumor angiogenesis

Nestin is a class Ⅵ intermediate filament protein that was originally described as a neuronal stem cell marker during central nervous system (CNS) development, and is currently widely used in that capacity. Nestin is also expressed in non-neuronal immature or progenitor cells in normal tissues. Under pathological conditions, nestin is expressed in repair processes in the CNS, muscle, liver, and infarcted myocardium. Furthermore, increased nestin expression has been reported in various tumor cells, including CNS tumors, gastrointestinal stromal tumors, pancreatic cancer, prostate cancer, breast cancer, malignant melanoma, dermatofibrosarcoma protuberances, and thyroid tumors. Nestin is reported to correlate with aggressive growth, metastasis, and poor prognosis in some tumors; however, the roles of nestin in cancer cells have not been well characterized. Furthermore, nestin is more specifically expressed in proliferating small-sized tumor vessels in glioblastoma and gastric, colorectal, and prostate cancers than are other tumor vessel markers. These findings indicate that nestin may be a marker for newly synthesized tumor vessels and a therapeutic target for tumor angiogenesis. It has received a lot of attention recently as a cancer stem cell marker in various cancer cells including brain tumors, malignant rhabdoid tumors, and uterine, cervical, prostate, bladder, head and neck, ovarian, testicular, and pancreatic cancers. The purpose of this review is to clarify the roles of nestin in cancer cells and in tumor angiogenesis, and to examine the association between nestin and cancer stem cells. Nestin has the potential to serve as a molecular target for cancers with nestin-positive cancer cells and nestin-positive tumor vasculature.

Selective tropism of liver stem cells to hepatocellular carcinoma in vivo

AIM： To investigate the selective tropism of liver stem cells to hepatocellular carcinoma （HCC） in an animal model and its feasibility as a vector to deliver therapeutic genes for targeted therapy of HCC.METHODS： WB-F344, a kind of rat liver stem cell, was infected with recombinant virus to establish a cell line with stable, high-level expressing enhanced green fluorescent protein （EGFP）. An animal model of HCC in Wistar rats was established by implanting HCC cells （CBRH7919） combined with an immunosuppressive drug. EGFP labeled liver stern cells were injected into caudal veins of the animals and distribution was observed at different time points after injection. SDF-1 and c-kit expression in non-tumor liver and tumor tissue were analysed by immunohistochemistry for the relationshiop between the expression and migration of liver stem cells. Furthermore, hepatic stern cells were injected via the portal vein, hepatic artery, caudal vein, or directly into the pericancerous liver tissue, respectively, and effects on migration, localization, and proliferation of the hepatic stern cells within the tumor tissue were observed and analyzed.RESULTS： Recombinant adenovirus could deliver the EGFP gene to hepatic stem cells. A new stem cell line, named WB-EGFP, was established that stably expressed EGFP. WB-EGFP cells still showed selective tropism towards HCC and EGFP expression was stable in vivo. According to immunohistochemistry results, SDF-1 may not be related to the mechanisms of tropism of hepatic stem cells. Different application sites affected the distribution of liver stem cells. Injection via the portal vein was superior with regard to selective migration, localization, and proliferation of the hepatic stem cells within the tumor tissue.CONCLUSION： Liver stem cells have the biological behavior of selective migration to HCC in vivo and they could localize and proliferate within HCC tissue stably expressing the target gene. Liver stem cells are a potential tool for a targeted gene therapy of HCC.

Inflammatory bowel disease: Moving toward a stem cell-based therapy

The incidence and prevalence of Crohn's disease (CD) and ulcerative colitis (UC), the two major forms of inflammatory bowel diseases (IBD), are rising in western countries. The modern hygienic lifestyle is probably at the root of a disease where, in genetically susceptible hosts, the intestinal commensal flora triggers dysregulated immune and inflammatory responses. Current therapies ranging from anti-inflammatory drugs to immunosuppressive regimens, remain inadequate. Advances in our understanding of the cell populations involved in the pathogenetic processes and recent findings on the regenerative, trophic and immunoregulatory potential of stem cells open new paths in IBD therapy. Hematopoietic and mesenchymal stem cells are catalyzing the attention of IBD investigators. This review highlights the pivotal fi ndings for stem cell-based approaches to IBD therapy and collects the encouraging results coming in from clinical trials.

Hepatic steatosis as a possible risk factor for the development of hepatocellular carcinoma after eradication of hepatitis C virus with antiviral therapy in patients with chronic hepatitis C

AIM: To elucidate risk factors contributing to the development of hepatocellular carcinoma (HCC) among patients with sustained viral response (SVR) after interferon (IFN) treatment and to examine whether HCV-RNA still remained in the liver of SVR patients who developed HCC. METHODS: Two-hundred and sixty-six patients, who achieved SVR, were enrolled in this study. We retrospectively reviewed clinical, viral and histological features of the patients, and examined whether the development of HCC depends on several clinical variables using Kaplan-Meier Method. RT-PCR was used to seek HCV-RNA in 3 out of 7 patients in whom liver tissue was available for molecular analysis. RESULTS: Among the enrolled 266 patients with SVR, HCC developed in 7 patients (7/266; 2.6%). We failed to detect HCV-RNA both in cancer and non-cancerous liver tissue in all three patients. The cumulative incidence for HCC was significantly different depending on hepatic fibrosis (F3-4) (P = 0.0028), hepatic steatosis (Grade 2-3) (P = 0.0002) and age (≥ 55) (P = 0.021) at the pre-interferon treatment. CONCLUSION: The current study demonstrated that age, hepatic fibrosis, and hepatic steatosis at pre- interferon treatment might be risk factors for developing HCC after SVR.

Umbilical cord mesenchymal stem cell transplantation for the treatment of Duchenne muscular dystrophy

Due to their relative abundance,stable biological properties and excellent reproductive activity,umbilical cord mesenchymal stem cells have previously been utilized for the treatment of Duchenne muscular dystrophy,which is a muscular atrophy disease.Three patients who were clinically and pathologically diagnosed with Duchenne muscular dystrophy were transplanted with umbilical cord mesenchymal stem cells by intravenous infusion,in combination with multi-point intramuscular injection.They were followed up for 12 months after cell transplantation.Results showed that clinical symptoms significantly improved,daily living activity and muscle strength were enhanced,the sero-enzyme,electromyogram,and MRI scans showed improvement,and dystrophin was expressed in the muscle cell membrane.Hematoxylin-eosin staining of a muscle biopsy revealed that muscle fibers were well arranged,fibrous degeneration was alleviated,and fat infiltration was improved.These pieces of evidence suggest that umbilical cord mesenchymal stem cell transplantation can be considered as a new regimen for Duchenne muscular dystrophy.

Differentiation of hepatocytoid cell induced from whole-bone-marrow method isolated rat myeloid mesenchymal stem cells

AIM： To explore the expansion and differentiation of hepatocytoid cell induced from myeloid mesenchymal stem cell （MSC） in vib＇o, in order to find suitable resource of hepatocytes for bioartiflcial liver or liver transplantation. METHODS： The rat myeloid MSC was isolated and divided into three groups which were cultured by Friedensteion method, and then were induced by culture fluid, culture fluid plus cholestatic serum and culture fluid plus hepatocyte growth factor （HGF）, respectively. Hepatocytoid cell as well as expression of CK18 and AFP was observed by immunohistochemistry. RESULTS： After the induction for 21 d, hepatocytoid cell was observed, and its expression of CK18 and AFP was detected by immunohistochemistry in MSC cultured with cholestatic serum. Furthermore, on the 35^th d, albumin mRNA was expressed in the cell, suggesting the inducing effect was similar to that by HGF.CONCLUSION： Rat myeloid MSC can differentiate into hepatocyte lineage under appropriate condition. This method is easy to operate.

Properties and feasibility of using cancer stem cells in clinical cancer treatment

Cancer treatment failure, drug resistance, or metastatic recurrence are thought to be caused mainly by the existence of a very small number of cancer stem cells(CSCs). The characteristics of this subgroup of cells include self-renewal, tumorigenesis, multiple differentiation and high invasiveness, metastasis, and drug resistance potential. Many studies have demonstrated that CSCs play important roles in tumor growth, spread and metastatic relapse after treatment, and are closely related to the prognosis of patients.From a therapeutic viewpoint, deep insights into the CSCs biology, development of specific therapeutic strategies for targeting CSCs, and characterization of their microenvironment could be an ideal way to combat cancer.

Characterization of pancreatic stem cells derived from adult human pancreas ducts by fluorescence activated cell sorting

AIM： To isolate putative pancreatic stem cells （PSCs） from human adult tissues of pancreas duct using serumfree, conditioned medium. The characterization of surface phenotype of these PSCs was analyzed by flow cytometry. The potential for pancreatic lineage and the capability of β-cell differentiation in these PSCs were evaluated as well. METHODS： By using serum-free medium supplemented with essential growth factors, we attempted to isolate the putative PSCs which has been reported to express nestin and pdx-1. The MatrigelTM was employed to evaluate the differential capacity of isolated cells. Dithizone staining, insulin content/secretion measurement, and immunohistochemistry staining were used to monitor the differentiation. Fluorescence activated cell sorting （FACS） was used to detect the phenotypic markers of putative PSCs. RESULTS： A monolayer of spindle-like cells was cultivated. The putative PSCs expressed pdx-1 and nestin. They were also able to differentiate into insulin-, glucagon-, and somatostatin-positive cells. The spectrum of phenotypic markers in PSCs was investigated; a similarity was revealed when using human bone marrow-derived stem cells as the comparative experiment, such as CD29, CD44, CD49, CD50, CD51, CD62E, PDGFR-α, CD73 （SH2）, CD81, CD105（SH3）. CONCLUSION： In this study, we successfully isolated PSCs from adult human pancreatic duct by using serumfree medium. These PSCs not only expressed nestin and pdx-1 but also exhibited markers attributable to mesenchymal stem cells. Although work is needed to elucidate the role of these cells, the application of these PSCs might be therapeutic strategies for diabetes mellitus.

Getting the right stuff: controlling neural stem cell state and fate in vivo and in vitro with biomaterials

Stem cell therapy holds great promises in medical treatment by, e.g., replacing lost cells, re-constitute healthy cell populations and also in the use of stem cells as vehicles for factor and gene delivery. Embryonic stem cells have rightfully attracted a large interest due to their proven capacity of differentiating into any cell type in the embryo in vivo. Tissue-specific stem ceils are however already in use in medical practice, and recently the first systematic medical trials involving human neural stem cell （NSC） therapy have been launched. There are yet many obstacles to overcome and procedures to improve. To ensure progress in the medical use of stem cells increased basic knowledge of the molecular mechanisms that govern stem cell characteristics is necessary. Here we provide a review of the literature on NSCs in various aspects of cell therapy, with the main focus on the potential of using biomaterials to control NSC characteristics, differentiation, and delivery. We summarize results from studies on the characteristics of endogenous and transplanted NSCs in rodent models of neurological and cancer diseases, and highlight recent advancements in polymer compatibility and applicability in regulating NSC state and fate. We suggest that the development of specially designed polymers, such as hydrogels, is a crucial issue to improve the outcome of stem cell therapy in the central nervous system.

Stem cells for end stage liver disease: How far have we got?

End stage liver disease (ESLD) is a health problem worldwide. Liver transplantation is currently the only effective therapy, but its many drawbacks include a shortage of donors, operative damage, risk of rejection and in some cases recidivism of the pre-transplant disease. These factors account for the recent growing interest in regenerative medicine. Experiments have sought to identify an optimal source of stem cells, sufficient to generate large amounts of hepatocytes to be used in bioartificial livers or injected in vivo to repair the diseased organ. This update aims to give non-stem cell specialists an overview of the results obtained to date in this fascinating field of biomedical research.

Adult stem cells as a tool for kidney regeneration

Kidney regeneration is a challenging but promisingstrategy aimed at reducing the progression to end-stagerenal disease （ESRD） and improving the quality of life of patients with ESRD. Adult stem cells are multipotent stem cells that reside in various tissues, such as bone marrow and adipose tissue. Although intensive studies to isolate kidney stem/progenitor cells from the adult kidney have been performed, it remains controversial whether stem/progenitor cells actually exist in the mammalian adult kidney. The effcacy of mesenchymal stem cells （MSCs） in the recovery of kidney function has been demonstrated in animal nephropathy models, such as acute tubular injury, glomerulonephritis, renal artery stenosis, and remnant kidney. However, their benefcial effects seem to be mediated largely via their paracrine effects rather than their direct differentiation into renal parenchymal cells. MSCs not only secrete bioactive molecules directly into the circulation, but they also release various molecules, such as proteins, mRNA, and microRNA, in membrane-covered vesicles. A detailed analysis of these molecules and an exploration of the optimal combination of these molecules will enable the treatment of patients with kidney disease without using stem cells. Another option for the treatment of patients with kidney disease using adult somatic cells is a direct/indirect reprogramming of adult somatic cells into kidney stem/progenitor cells. Although many hurdles still need to be overcome, this strategy will enable bona fde kidney regeneration rather than kidney repair using remnant renal parenchymal cells.

Therapeutic application of stem cells in gastroenterology:An up-date

Adult stem cells represent the self-renewing progenitors of numerous body tissues, and they are currently classified according to their origin and differentiation ability. In recent years, the research on stem cells has expanded enormously and holds therapeutic promises for many patients suffering from currently disabling diseases. This paper focuses on the possible use of stem cells in the two main clinical settings in gastro-enterology, i.e., hepatic and intestinal diseases, which have a strong impact on public health worldwide. Despite encouraging results obtained in both regenerative medicine and immunemediated conditions,further studies are needed to fully understand the biology of stem cellsand carefully assess their put ativeonco- genicproperties.Moreover,there searchonstemcellsarousesferventethical,socialandpoliticaldebate.TheItalianSocietyofGastroenterologysponsoredaworkshoponstemcellsheldinVeronaduringtheⅩⅥCongressoftheFederationofItalianSocietiesofDigestiveDiseases(March 6-9,2010).Here,we report on the issues discussed,including liver and intestinal diseases that may benefit from stemcell therapy,the biology of hepatic and intestinal tissue repair,and stem cell usage inclinical trials.