Resuscitation from experimental heatstroke by estrogen therapy

OBJECTIVE: We investigated the effect of estrogen therapy on inflammatory responses, cardiovascular functions, and survival in a rat model of heatstroke. DESIGN: Controlled, prospective study. SETTING: Hospital medical research laboratory. SUBJECTS: Sprague-Dawley rats (280-312 g of body weight, males and females). INTERVENTIONS: Four major groups of anesthetized rats were designated for experiments: a) vehicle-treated male rats; b) vehicle- or premarin-treated estrus female rats; c) vehicle- or premarin-treated ovariectomized rats; and d) vehicle- or premarin-treated leuprolide-treated rats. All animals were exposed to heat stress (ambient temperature 43 degrees C for 70 mins) and then allowed to recover at room temperature (24 degrees C). Their survival time (interval between the onset of heatstroke and animal death) and physiologic and biochemical variables were monitored. Vehicle (normal saline 1 mL/kg of body weight, intravenously) or premarin (1 mg/mL/kg of body weight, intravenously) was administered 70 mins after initiation of heat stress. Ovariectomy or leuprolide (100 mug/kg/day, subcutaneously) injection was conducted 4 wks before the start of heat stress experiments. Another group of rats were exposed to 24 degrees C and used as normothermic controls. MEASUREMENTS AND MAIN RESULTS: Compared with the estrus female rats, the ovariectomized rats, the leuprolide-treated rats, and male rats all had lower levels of plasma estradiol and lower survival time values. However, after an intravenous dose of premarin, both the plasma estradiol and survival time values were significantly increased. Compared with the normothermic controls, the vehicle-treated male and ovariectomized rats all displayed higher levels of serum tumor necrosis factor-alpha, which could be suppressed by premarin therapy. In contrast, the serum levels of IL-10 in these groups were significantly elevated by premarin during heatstroke. Furthermore, the heatstroke-induced hyperthermia, arterial hypotension, intracranial hypertension, and cerebral hypoperfusion, hypoxia, and ischemia were significantly attenuated by premarin therapy in ovariectomized rats. CONCLUSIONS: We successfully demonstrated that estrogen replacement may improve survival during heatstroke by ameliorating inflammatory responses and cardiovascular dysfunction.     

Resuscitation from experimental heatstroke by hyperbaric oxygen therapy

OBJECTIVE: Heatstroke is characterized by hyperthermia, vasoplegic shock, and cerebral ischemia and hypoxia. Hyperbaric oxygen (HBO) has been shown to reduce brain ischemia and behavioral dysfunction during cerebral artery occlusion. The efficacy of HBO therapy for resuscitation from heatstroke remains to be determined in the laboratory. DESIGN: Anesthetized rats were randomized to several groups and administered: 1) no resuscitation (normobaric air) after onset of heatstroke, 2) HBO for 1 hr (100% oxygen at 253 kPa for 1 hr), 3) cyclic HBO intermitted by a 5-min air break for 1 hr of treatment (100% oxygen at 253 kPa), 4) hyperbaric air (air at 253 kPa for 1 hr), 5) normobaric hyperoxia (100% oxygen at 101 kPa for 1 hr), or 6) 8% HBO (hyperbaric 8% oxygen at 253 kPa for 1 hr). SETTING: Laboratory investigation. SUBJECTS: Sprague-Dawley rats (300- to 400-g males). INTERVENTIONS: Rats were exposed to an ambient temperature of 43 degrees C to induce heatstroke. Their colonic temperature; mean arterial pressure; heart rate; arterial blood levels of pH, Paco2, Pao2, So2%, and tumor necrosis factor-alpha; the cortical levels of ischemic and damage markers, and cortical neuronal damage scores were determined. The moment at which mean arterial pressure began to decrease from peak levels was arbitrarily taken as the onset of heatstroke. MAIN RESULTS: Survival time (interval between onset of heatstroke and animal death) was 19 +/- 1 (n = 10), 131 +/- 18 (n = 14), 159 +/- 28 (n = 13), 72 +/- 14 (n = 10), 68 +/- 12 (n = 10), and 45 +/- 11 (n = 10) mins, respectively, for normobaric air, HBO for 1 hr, cyclic HBO, hyperbaric air, normobaric hyperoxia, and 8% HBO groups. The heatstroke induced arterial hypotension and bradycardia, decreased arterial levels of pH, Pao2, and So2%, increased arterial levels of tumor necrosis factor-alpha, and increased values of cellular ischemia and damage markers. In addition, neuronal damage scores in the cortex were significantly reduced by HBO for 1 hr and cyclic HBO resuscitation. CONCLUSION: We successfully demonstrated that HBO and, to some extent, hyperbaric air, normobaric hyperoxia, or HBO 8% was found beneficial in resuscitating rats with experimental heatstroke. HBO effectively reduced heatstroke-induced arterial hypotension, hypoxia, plasma tumor necrosis factor-alpha overproduction, and cerebral ischemia and damage and improved survival.     

Resuscitation from experimental heatstroke by brain cooling therapy

We have used hypothermic retrograde jugular venous flush to cool the brain previously and to provide better resuscitation than peripheral cold saline infusion during heatstroke in the rat. The current study was performed to assess the effects of brain cooling further on production of reactive nitrogen species, reactive oxygen species, tumor necrosis factor-alpha, and interleukin-10 in both serum and brain during heatstroke. Rats, under general anaesthesia, were randomized into the following groups and given: (a) 36 degrees C or (b) 4 degrees C saline infusion in the external jugular vein immediately after onset of heatstroke. They were exposed to an ambient temperature of 43 degrees C for exactly 70 min to induce heatstroke. When the 36 degrees C saline-treated rats underwent heat stress, their survival time values were found to be 21-25 min. Immediately after the onset of heatstroke, resuscitation with an i.v. dose of 4 degrees C saline greatly improved survival (226-268 min). Compared with the normothermic controls, the 36 degrees C saline-treated heatstroke rats displayed higher levels of brain temperature, intracranial pressure, serum and hypothalamic nitric oxide metabolite, tumor necrosis factor-alpha and dihydroxybenzoic acid as well as hypothalamic inducible nitric oxide synthase immunoreactivity. In contrast, the values of mean arterial pressure, cerebral perfusion pressure, and hypothalamic levels of local blood flow, and partial pressure of oxygen were all significantly lower during heatstroke. The cerebrovascular dysfunction, the increased levels of nitric oxide metabolites, tumor necrosis factor-alpha, and dihydroxybenzoic acid in both the serum and the hypothalamus, and the increased levels of hypothalamic inducible nitric oxide synthase immunoreactivity occurred during heatstroke were significantly suppressed by brain cooling. Although the serum and hypothalamic interleukin-10 maintained at a negligible level before stress, they were significantly elevated by brain cooling during heatstroke. These findings suggest that brain cooling may resuscitate persons who had heatstroke by decreasing overproduction of reactive nitrogen species, tumor necrosis factor-alpha, reactive oxygen species and cerebrovascular dysfunction, but increasing production of interleukin-10.     

人脐血单个核细胞和脐带间充质干细胞移植用于大鼠脊髓损伤的实验研究

目的:探讨人脐血单个核细胞和脐带间充质干细胞(MSCs)移植对脊髓损伤功能恢复的影响,寻找一种更适合治疗脊髓损伤的细胞源。方法:采集新鲜人脐带血和脐带,分离培养单个核细胞和MSCs。将脊髓损伤模型随机分成3组:单个核细胞移植组、MSCs移植组和低糖必需培养基(L-DMEM)培养组。采用免疫组化和免疫荧光检测细胞移植后1—4周细胞在脊髓内的存活情况和迁移情况,使用BBB行为学评分评估大鼠脊髓功能恢复情况。结果:L-DMEM培养液组在术后各时间点观察评分无明显差异,而细胞移植组脊髓功能处于逐渐恢复过程,与L-DMEM培养液比较,差异有显著性意义。单个核细胞移植组对损伤脊髓功能的修复作用较MSCs移植组显著,且差异有显著性意义。结论:与MSCs相比较,人脐血单个核细胞更适合作为治疗脊髓损伤的细胞源。     

脐血间充质干细胞支持下脐血单个核细胞扩增的研究

目的 探讨脐血源间充质干细胞联合外源性细胞因子对脐血单个核细胞体外扩增的支持作用.方法 从脐血中分离、培养出间充质干细胞并检测其细胞表面抗原;以此间充质干细胞作为细胞滋养层.将脐血单个核细胞接种于无血清培养体系中培养18天,在第0、7、10、14及18天检测有核细胞总数、CD34+、CDl33+细胞数、集落形成单位数和(G2+M+S)期细胞含量变化.结果 ①从脐血中分离、培养出的间充质干细胞能稳定表达CD29、CD105和CD44,但不表达CD34和CD133;②外源性细胞因子及脐血源间充质下细胞均支持脐血间充质干细胞扩增,但以细胞因子联合脐血源间充质干细胞组效果最好,在第10天上述榆测指标达到峰值,分别为第0天的(6.91±1.91)、(7.75±1.24)、(6.49±1.33)、(15.62±1.29)和(28.26±6.58)倍,且维持造血至少18天.结论 ①从脐血巾能成功分离、培养出间充质下细胞,并完成细胞表型的初步鉴定;②外源性细胞因子联合脐血源间允质干细胞可有效扩增脐血单个核细胞.     

Human umbilical cord blood-derived CD34+ cells cause attenuation of multiorgan dysfunction during experimental heatstroke

Multiorgan dysfunction ensuing from severe heatstroke includes hypotension, hepatic and renal failure, hypercoagulable state, activated inflammation, and cerebral ischemia and injury. We attempted to assess whether human umbilical cord blood-derived CD34+ cell therapy improves survival during experimental heatstroke by attenuating multiorgan dysfunction. Anesthetized rats, immediately after the onset of heatstroke, were divided into 2 major groups and given CD34- or CD34+ cells (1 x 10(5)-5 x 10(5)/mL/kg body weight) i.v. They were exposed to ambient temperature of 43 degrees C to induce heatstroke. Another group of rats were exposed to room temperature (26 degrees C) and used as normothermic controls. Hypotension, hepatic and renal failure (evidenced by increased serum urea nitrogen, creatinine, aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase levels in plasma), hypercoagulable state (evidenced by increased prothrombin time, activated partial thromboplastin time, and D-dimer, and decreased platelet count and protein C in plasma), activated inflammation (evidence by increased TNF-alpha levels in serum), and cerebral dysfunction (evidenced by intracranial hypertension, cerebral hypoperfusion and hypoxia, and cerebral ischemia and injury) were monitored. When the CD34- cell-treated or untreated rats underwent heat stress, their survival time values were found to be 19 to 23 min. Resuscitation with CD34+ cells significantly improved survival time (duration, 63-291 min). As compared with normothermic controls, all CD34- cell-treated heatstroke animals displayed hypotension, hepatic and renal failure, hypercoagulable state, activated inflammation, and cerebral ischemia and injury. However, CD34+ cell therapy significantly caused attenuation of all the above-mentioned heatstroke reactions. In addition, the levels of IL-10 in plasma and glial cell line-derived neurotrophic factors in brain were all significantly increased after CD34+ cell therapy during heatstroke. Our data indicate that CD34+ cell therapy may resuscitate persons who had a heatstroke by reducing multiorgan dysfunction or failure.     

人脐血贴壁层细胞对脐血造血细胞体外扩增的作用

实验于2004-10/2005-06在吉林省肿瘤防治研究所和吉林医药学院病原教研室完成。脐血采自长春市妇产医院健康产妇,知情同意,足月顺产,待胎儿娩出后,无菌经脐静脉穿刺取血,枸橼酸钠抗凝。Ficoll-paque淋巴细胞分层液(相对体积质量:1.077±0.22)密度梯度离心法分离出脐带血单个核细胞后,采用长期液体培养法培养脐带血贴壁层细胞,并与脐带血单个核细胞共同培养,观察细胞生长形态并通过流式细胞仪分析细胞周期。结果显示,脐带血贴壁层细胞与脐带血单个核细胞共培养7d后,与无贴壁层细胞培养的脐带血单个核细胞的细胞周期相比,贴壁层细胞能明显促进细胞的增殖,S G2 M期细胞百分数明显增高,差异具有显著性意义[(42.7±1.1)%,(35.5±2.8)%,P<0.05]。脐血贴壁层细胞能促进脐血单个核细胞进入细胞周期,体外扩增后的脐血单个核细胞集落形成能力明显大于无贴壁细胞[(57.7±4.7)个/5×104,(40.3±5.1)个/5×104,P<0.01]。     

诱导扩增脐血单个核细胞为T/NK细胞的实验研究

目的　探索体外诱导脐血单个核细胞 (MNC)扩增分化为T/NK细胞的最佳培养体系。方法　脐血MNC在 6种培养体系中培养 4周 ,于各时间点用流式细胞仪测定细胞表面T/NK标志抗原的表达 ;测定有核细胞 (NC)数 ;并行细胞形态学鉴定及细胞毒功能实验。结果　脐血MNC在SCF +FLT 3L +IL 7+IL 15 +TNF α +IL 2体系中培养 ,第 2 2天NC数达 (2 0～ 2 6 )× 10 6/ml;淋巴细胞占NC的比例和CD3 + T细胞占淋巴细胞的比例均达到 90 %以上 ,以CD8+ T细胞亚群为主 ,CD4+ T细胞亚群比例下降 ;CD56+ CD3 + NKT细胞和TCRγδ+ 细胞的比例分别由不足 2 %升高到 30 %～ 4 0 %和 10 %～ 15 %。CD3 -CD56+ NK细胞无扩增。培养后细胞在效靶比为 5 0∶1时对K5 6 2细胞和Raji细胞的杀伤率分别达75 %以上和 32 %～ 6 5 %。结论　本实验中体外诱导脐血MNC扩增分化为T/NK细胞的最佳培养体系为SCF +FLT 3L +IL 7+IL 15 +TNF α+IL 2 ,最佳扩增时间是培养后第 2 2天。     

脐血单个核细胞体外诱导分化为肝样细胞的可行性

目的:细胞移植为重度肝损伤治疗提供了一条新的途径,但肝细胞来源仍是一个未解决的问题.实验采用体外培养体系,观察人脐血单个核细胞是否可以诱导分化为肝样细胞,以期为治疗肝脏疾病提供了新的细胞来源. 方法:实验于2006-10/2007-08在解放军第一二三医院南京军区肝病中心实验室完成.①实验材料:脐血由蚌埠解放军123医院妇产科提供,产妇及家属对实验知情同意,并经医院伦理委员会批准.②实验方法:分离获得脐血单个核细胞后,将其分组培养:对照组不加细胞因子,实验组加入重组人肝细胞生长因子、重组人成纤维生长因子4和重组人制瘤素.③实验评估:于诱导前及诱导后第7,14,21,28天采用免疫细胞化学染色检测甲胎蛋白、细胞角蛋白18、白蛋白和肝细胞抗体的表达,应用流式细胞仪检测细胞中白蛋白表达,放射免疫法检测细胞培养液中甲胎蛋白的分泌水平. 结果:①免疫细胞化学染色显示,实验组第7天可见甲胎蛋白染色阳性细胞,第21天后染色基本为阴性,第7天未检测到细胞角蛋白18和白蛋白阳性表达,随着诱导时间的延长,呈阳性表达,阳性率逐渐增高.对照组染色均呈阴性.②实验组培养第21天时检测到糖原染色阳性细胞,28 d时呈强阳性表达.对照组糖原染色呈阴性.③流式细胞仪检测实验组白蛋白阳性细胞比例逐渐增高,第28天达80%.放射免疫法检测7 d的甲胎蛋白水平达到最高,与诱导前和对照组差异显著(P < 0.05).结论:在特定细胞生长因子诱导下,脐血单个核细胞能够分化为肝样细胞.     

非血缘脐血移植的展望

近年,非血缘脐血移植(UCBT)的广泛开展,为恶性及非恶性血液病患者的治疗提供了更多选择.本文将从脐血的选择、预处理方案、植入前综合征(PES)、植入失败和复发的处理等方面,对UCBT的最新进展及前景进行总结.     

脐血间充质干细胞移植与免疫调节

背景：近年研究显示,脐血间充质干细胞的自我更新和多向分化潜能为细胞移植治疗提供了基础条件,而其免疫调节功能也极大地拓展了细胞治疗的方向和范围。目的：就近期脐血间充质干细胞的免疫调节和细胞移植研究进行回顾分析。方法：应用计算机以＂umbilical cord blood-derived mesenchymal stem cells＂为关键词检索Pubmed数据库,以＂脐血间充质干细胞＂为关键词检索知网数据库,时间限定为2008-01/2011-06,语言种类为＂English＂和汉语。通过阅读标题和摘要进行初筛,排除研究内容与此文无关的文献、重复性研究及Meta分析,选择近期发表或发表在权威杂志的30篇文献进行综述。结果与结论：脐血间充质干细胞具有与骨髓间充质干细胞相似的自我更新和多向分化潜能。通过细胞移植技术,脐血间充质干细胞在糖尿病、神经退化性疾病如阿尔茨海默病和帕金森病等以及神经损伤后的修复治疗方面显示出很强的潜力。同时,脐血间充质干细胞又具有免疫调节作用,其可通过下调T细胞的增殖,降低免疫反应。利用该特点,脐血间充质干细胞在一些免疫性疾病,如移植物抗宿主病和狼疮性肾炎等疾病的细胞治疗方面也取得了积极的进展。     

脐血干细胞移植治疗脑卒中的研究现状

学术背景：目前传统的方法无法从根本上改善脑卒中后所造成的神经功能缺损，欲达到理想的恢复还赖于脑功能的重建。近年研究发现，脐血干细胞在特定诱导条件下可分化为神经细胞，修复受损的神经。 目的：总结脐血干细胞移植治疗脑卒中的研究进展。检索策略：由第一作者应用计算机检索PubMed数据库与万方数据库1995／2007年期间相关文献，检索词为“cord blood stem cells，Stroke，脐血干细胞，脑卒中”，并手工查阅相关书籍。对资料进行初审，选择脐血干细胞研究及采用脐血干细胞移植治疗脑卒中的研究，排除综述及重复文献。共检索到50篇相关文献。 文献评价：选择其中的31篇，文献的来源主要是脐血干细胞研究及采用脐血干细胞移植治疗脑卒中的动物及基础实验研究。 资料综合：脐血干细胞具有自我更新、增殖和多向分化潜能，在合适诱导下可分化为神经细胞。研究表明，脐血干细胞在体外诱导及体内移植能生成神经样细胞，能表达神经元表达神经元特异性标志物nestin、NF-M、NeuN、MAP2等。脐血干细胞治疗脑卒中在动物及实验研究基础上已取得了较大成就，但仍存在许多问题，细胞体外培养中分化增值的调控机制不十分清楚，临床研究报道甚少，诱导生成的神经细胞存活的时间,能否跟正常神经细胞一样发挥功能等，待进一步探讨。 结论：用来源丰富、免疫排斥概率小的脐血干细胞治疗多发的脑卒中，具有明显的优越性，为脑血管疾病患者神经功能的恢复带来新的希望。     

影响脐血间充质干细胞分离培养的关键环节

背景:脐血中存在间充质干细胞,目前国内外尚未见到对脐血间充质干细胞体外分离、培养及扩增较统一且有效的方法.目的:探讨影响人脐血间充质干细胞成功分离培养的相关因素.方法:分别从不同胎龄(≥40周,37周和≤32周),脐血中单个核细胞数量(≥2.5× 109 L-1,< 2.5×109 L-1),不同细胞接种浓度(1×107,1×109,1×1011 L-1),不同体积分数胎牛血清(5%,10%,15%,20%)以及培养瓶是否被胎牛血清包被等方面对人脐血间充质干细胞分离培养成功率进行比较.结果与结论:脐血间充质干细胞的分离培养成功率为58.3%,且随胎龄的增高而培养成功率降低(P < 0.01);脐血中单个核细胞浓度≥2.5×109 L-1组培养成功率高于< 2.5×109 L-1组(P < 0.01);相同容量脐血中单个核细胞数量与胎龄呈负相关(r = -0.95,P < 0.01);1×1011 L-1组原代及传代培养的间充质干细胞生长及扩增情况高于1×107,1×109 L-1;体积分数5%FBS组间充质干细胞贴壁速度较其他3组略慢,但细胞纯度较高,且细胞传代速度与其他3组无明显差别;胎牛血清包被组脐血间充质干细胞原代和传代后的纯度及扩增能力均高于未包被组.提示脐血间充质干细胞分离培养成功率受多种因素的影响:通过选择较低胎龄的胎儿,采集足够量的脐血,以较高的细胞密度接种,培养基中添加较低浓度的胎牛血清,并将培养瓶预先用胎牛血清进行包被,能在体外建立稳定的脐血间充质干细胞培养体系.     

影响脐血间充质干细胞分离培养的关键环节

背景：脐血中存在间充质干细胞,目前国内外尚未见到对脐血间充质干细胞体外分离、培养及扩增较统一且有效的方法。目的：探讨影响人脐血间充质干细胞成功分离培养的相关因素。方法：分别从不同胎龄（≥40 周,37 周和≤32 周）,脐血中单个核细胞数量（≥2.5×109L-1,〈2.5×109 L-1）, 不同细胞接种浓度（1×107,1×109,1×1011 L-1）,不同体积分数胎牛血清（5%,10%,15%,20%）以及培养瓶是否被胎牛血清包被等方面对人脐血间充质干细胞分离培养成功率进行比较。结果与结论：脐血间充质干细胞的分离培养成功率为 58.3%,且随胎龄的增高而培养成功率降低（P〈0.01）;脐血中单个核细胞浓度≥2.5×109 L-1组培养成功率高于〈2.5×109 L-1组（P〈0.01）;相同容量脐血中单个核细胞数量与胎龄呈负相关（r=-0.95,P〈0.01）;1×1011 L-1 组原代及传代培养的间充质干细胞生长及扩增情况高于 1×107,1×109 L-1;体积分数 5%FBS 组间充质干细胞贴壁速度较其他 3 组略慢,但细胞纯度较高,且细胞传代速度与其他 3 组无明显差别;胎牛血清包被组脐血间充质干细胞原代和传代后的纯度及扩增能力均高于未包被组。提示脐血间充质干细胞分离培养成功率受多种因素的影响：通过选择较低胎龄的胎儿,采集足够量的脐血,以较高的细胞密度接种,培养基中添加较低浓度的胎牛血清,并将培养瓶预先用胎牛血清进行包被,能在体外建立稳定的脐血间充质干细胞培养体系。     

人脐血间充质干细胞尾静脉移植治疗扩张型心肌病

背景：体外研究表明人脐血间充质干细胞可分化为自律性跳动的心肌细胞,而经静脉移植人脐血间充质干细胞治疗扩张型心肌病心力衰竭的报道较少。目的：探讨经尾静脉移植人脐血间充质干细胞对扩张型心肌病大鼠心肌结构、心功能的影响。方法：Wistar大鼠通过腹腔注射阿霉素诱导扩张型心肌病模型,扩张型心肌病实验组于造模后8周经尾静脉移植人脐血间充质干细胞,扩张型心肌病对照组注射等量DMEM培养基。健康对照组不造模,于相同时间点注射等体积的生理盐水。结果与结论：与健康对照组相比,扩张型心肌病组心功能明显受损,且扩张型心肌病实验组受损较扩张型心肌病对照组轻;移植的细胞有肌钙蛋白T的表达。结果提示人脐血间充质干细胞移植能促进扩张型心肌病大鼠心功能恢复,使心肌组织病变减轻。     

In vitro clinical-grade generation of red blood cells from human umbilical cord blood CD34+ cells

BACKGROUND: There is no appropriate alternative source of red blood cells (RBCs) to relieve the worsening shortage of blood available for transfusion. Therefore, in vitro generation of clinically available RBCs from hematopoietic stem cells could be a promising new source to supplement the blood supply. However, there have been few studies about the generation of clinical‐grade RBCs by coculture on human mesenchymal stem cells (MSCs) and various cytokine supplements, even though the production of pure RBCs requires coculture on stromal cells and proper cytokine supplements. STUDY DESIGN AND METHODS: Umbilical cord blood (CB) CD34+ cells were cultured in serum‐free medium supplemented with two cytokine sets of stem cell factor (SCF) plus interleukin‐3 (IL‐3) plus erythropoietin (EPO) and SCF plus IL‐3 plus EPO plus thrombopoietin (TPO) plus Flt‐3 for 1 week, followed by coculture upon MSCs derived from bone marrow (BM) or CB for 2 weeks. RESULTS: Almost pure clinical‐grade RBCs could be generated by coculturing with CB‐MSCs but not BM‐MSCs. Expansion fold and enucleation rate were significantly higher in coculture with CB‐MSCs than BM‐MSCs. Despite a 2.5‐fold expansion of erythroblasts in the presence of TPO and Flt‐3 for 8 days, the final RBC count was higher without TPO and Flt‐3. CONCLUSIONS: This study is the first report on generating clinical‐grade RBCs by in vitro culture with human MSCs and compared effectiveness of several cytokines for RBC production. This provides a useful basis for future production of clinically available RBCs and a model of erythropoiesis that is analogous to the in vivo system.     

人脐血干细胞移植建立人鼠嵌合体动物模型实验研究

目的 探讨人脐血干细胞移植后,在BALB/C小鼠肝内建立人鼠嵌合体模型的可能性.方法 分离男婴脐血单个核细胞,将该细胞悬液注射至肝部分切除的雌性BALB/C小鼠肝内;以磷酸盐缓冲生理盐水(PBS)注射肝部分切除小鼠肝内为肝切除对照组.以仅作腹腔切开为空白对照组.于术后7、14天分别处死人脐血干细胞移植组、肝切除时照组和空白对照组各8只小鼠,眶底静脉丛采血检测肝功能;取肝组织原位杂交检测Y染色体(移植细胞标记).结果 术后7、14天人脐血干细胞移植组小鼠注射肝叶与非注射肝叶内可检出Y染色体阳性细胞,并可见嵌入肝板.结论 人脐血干细胞移植BALB/C小鼠可以建立人鼠嵌合体动物模型.     

NOD/SCID小鼠脐血单个核细胞骨髓腔内移植的实验研究

目的观察骨髓腔内移植(iBM)人脐血单个核细胞(MNC)对小鼠造血重建和免疫功能恢复的作用。方法NOD/SCID小鼠经137Cs全身照射后,在4h内无菌条件下局部麻醉后从尾静脉或骨髓腔内输注分离脐血MNC。受体小鼠随机分为5组:①对照组:骨髓腔内输注培养液;②阳性对照组(iTV):尾静脉输注脐血MNC3×107/只;③实验Ⅰ组(iBM1):骨髓腔内输注脐血MNC3×106/只;④实验Ⅱ组(iBM2):骨髓腔内输注脐血MNC1×107/只;⑤实验Ⅲ组(iBM3):骨髓腔内输注脐血MNC3×107/只。对照组4只小鼠,实验Ⅱ组7只小鼠,其余每组5只。24h后观察iBM22只小鼠未移植侧胫骨骨髓腔脐血细胞的迁移分布,动态观察移植后小鼠的存活和造血重建情况,7～8周后处死各组小鼠,检测骨髓细胞表面CD分子表达、碳青花(DilCM)染料示踪研究和脐血βactin的DNA标记。结果①照射后骨髓腔内输注脐血MNC,24h后在未输注脐血MNC的一侧胫骨骨髓细胞膜有DilCM标记;②7～8周后小鼠存活14只,其中对照组存活1只,iTV组、iBM1组各存活2只,iBM2组存活4只,iBM3组存活5只;③外周血常规检查结果显示iBM组白细胞的恢复速度比iTV组和对照组快而且稳定;④移植后存活小鼠骨髓细胞表面CD45标记、DilCM染料示踪研究和βactin均显示人源的标记。结论经iBM途径移植脐血MNC至NOD/SCID小鼠骨髓可以重     

脑源性神经营养因子基因修饰的人脐血干细胞移植对损伤脊髓组织的保护

目的:观察损伤脊髓组织经脑源性神经营养因子基因修饰的人脐血干细胞移植后,细胞内环境的改善及下肢运动功能、电生理指标的变化。方法:实验于2005-10/2006-09在广东医学院实验动物中心完成。①选取清洁级SD大鼠96只,随机数字表法分为4组:基因修饰细胞移植组、单纯细胞移植组、损伤对照组、正常对照组,24只/组。新鲜脐带血来源于广东医学院妇产科健康产妇,产妇及其家属均知情同意。脑源性神经营养因子的DNA由解放军第二军医大学提供。②基因修饰细胞移植组、单纯细胞移植组、损伤对照组大鼠制备脊髓半横断损伤模型,无菌条件下显露T7～9棘突及椎板,暴露T8平面脊髓,用弯刀将左侧半脊髓横向切断,再用负压吸引器吸除脊髓组织,形成一个2mm×2mm×2mm的间隙。③采集人脐血单个核细胞,以1×109L-1密度接种于含10mLDMEM/F12的培养皿中,同时以终浓度5μmol/L的Brdu标记,置于含体积分数为0.05的CO2细胞培养箱中,48h后磷酸盐缓冲液反复离心洗涤,制备密度为6×109L-1的人脐血干细胞悬液,进行脑源性神经营养因子DNA质粒的提取、鉴定、纯化,转染。④将转染的人脐血干细胞悬液重悬为2.5×1010L-1,取3μL浸透在与宿主脊髓损伤间隙大小一致的明胶海棉上,并将其植入基因修饰细胞移植组大鼠脊髓损伤处,确认植入后缝合硬脊膜、肌层及皮肤。单纯细胞移植组单纯植入含2.5×1010L-1高纯化的人脐血干细胞3μL的明胶海绵。损伤对照组仅植入明胶海绵。⑤移植术后24h,每组取8只大鼠进行脊髓水肿程度及离子含量检测。移植术后6,12周,每组各取8只大鼠以爬坡试验检测其下肢运动功能情况,并采用颅刺激法检查运动诱发电位。结果:各组24只SD大鼠均进入结果分析。①脊髓水肿程度及离子含量:脊髓损伤后组织水肿及Na 、Ca2 含量升高,K 、Mg2 含量降低,经脑源性神经营养因子基因修饰的人脐血干细胞脊髓内移植后可显著改善上述指标。与损伤对照组比较,基因修饰细胞移植组脊髓含水量及Na 、Ca2 含量显著降低(t=1.77～1.79,P均<0.05),K 、Mg2 含量升高(t=2.05～2.41,P均<0.05)。②下肢运动功能评估:移植术后6周,除正常对照组外各组大鼠左下肢均瘫痪,爬坡试验为0级。移植术后12周,基因修饰细胞移植组大鼠肌力恢复至Ⅱ级,单纯细胞移植组恢复至Ⅰ级。损伤对照组0级。③电生理检查:移植术后6周,基因修饰细胞移植组记录到运动诱发电位,而单纯细胞移植组、损伤对照组未记录到。术后12周,基因修饰细胞移植组、单纯细胞移植组大鼠均记录到运动诱发电位,但与基因修饰细胞移植组比较,单纯细胞移植组运动诱发电位潜伏期延长,波幅降低;损伤对照组仍未记录到运动诱发电位。结论:脑源性神经营养因子基因修饰的人脐血干细胞脊髓内移植对脊髓损伤起保护作用,其机制可能与减少神经细胞离子失衡、改善细胞内环境有关。     

Mesenchymal stem cells from CD34− human umbilical cord blood

Umbilical cord blood (UCB) is well known to be a rich source of stem cells especially for haematopoietic stem cells (HSCs). Recently, mesenchymal stem cells (MSCs) have also been shown to exist in cord blood. Although MSCs have been described by a subset of surface antigens after expansion, little is known about the cell surface phenotype of undifferentiated MSCs. The aim of this study therefore was to clarify whether undifferentiated MSCs are resident among CD34^? UCB cells. CD34⁺ cells were separated from UCB mononuclear cells (MNCs) by magnetic sorting and the CD34^? cell fractions were cultured in Dulbecco's modified Eagle's medium (DMEM) with 10% foetal calf serum (FCS) and basic‐fibroblast growth factor. Isolated CD34⁺ cells were also cultured in the same medium. Adherent fibroblast‐like cells at passage 3–4 were analyzed by fluorescence‐activated cell sorting (FACS) for MSC marker expression , and standard adipogenic, osteogenic and chondrogenic assays were used to investigate their differentiation potentials. After 4–5 weeks in culture, the cells from the CD34^? fraction became confluent with flat and fibroblast‐like morphology. These cells were positively stained for the mesenchymal cell markers CD29, CD73 and CD105. In adipogenic differentiation, the cells showed oil red O positive and expressed FABP4, adipsin and proliferation‐activated receptor γ‐2 (PPARγ2 genes) associated with adipogenesis. In osteogenic differentiation, calcium accumulation and osteocalcin were detected. The cells grown in chondrogenic conditions were positively stained for human aggrecan and expressed collagen type II and Sox‐9 genes. In contrast, cells from the CD34⁺ fraction failed to generate any cells with MSC morphology under the same culture conditions. Our results showed that UCB contained MSCs which are only resident in the CD34^? fraction. The MSCs could be induced to differentiate into at least three lineage cell types, adipocytes, osteoblasts and chondrocytes.