骨髓间充质干细胞对创伤性骨折愈合的促进作用

BACKGROUND:In recent years, the development of stem cell culture and isolation technologies provides new therapeutic choices for fracture healing. OBJECTIVE:To investigate the effect of exogenous bone marrow mesenchymal stem cells on bone fracture healing in traumatic fracture rats and on the migration ability of endogenous bone marrow mesenchymal stem cells. METHODS:Femoral fracture models were made in 48 Wistar rats and then randomized into experimental group and control group (n=24/group). Bone marrow mesenchymal stem cells from another healthy rats were isolated using adherent method and then injected into the rats via the tail vein in the experimental group. Rats in the control group were given the same volume of normal saline. At 2, 3, 4, 8, 12 weeks after injection, we extracted bone marrow mesenchymal stem cells from the femur of rats in the two groups. RT-qPCR was used to detect expression levels of type I collagen and CD44. Transwell method was used to detect cell migration ability. Immunohistochemitry method was employed to detect expression of nerve growth factors in the callus. RESULTS AND CONCLUSION:mRNA levels of type I collagen and CD44 in rat bone marrow mesenchymal stem cells were significantly higher in the experimental group than the control group at 2, 3 and 4 weeks after injection (P < 0.05). Compared with the control group, the higher migration ability of bone marrow mesenchymal stem cells was found in the experimental group at 2 and 3 weeks after injection (P < 0.05) as well as the higher expression of nerve growth factor in the callus in the experimental group at 3, 4, 8, 12 weeks after injection. All these findings suggest that exogenous bone marrow mesenchymal stem cells can improve the migration ability of endogenous bone marrow mesenchymal stem cells and the expression of nerve growth factor in the callus in rats with femoral fracture, thereby promoting fracture healing in rats.     

Interleukin-12 administration in retroviral infection of mice increases the potential to produce functional dendritic cells from bone marrow stem cells

Rauscher leukaemia virus (RLV) infection in mice causes production of lymph node and skin dendritic cells (DC) that fail to stimulate a primary mixed leukocyte reaction (MLR). Treatment of mice with IL-12 around the time of infection results in DC with normal stimulatory function (N.J. Williams, J.J. Harvey, I. Duncan, R.F.G. Booth, S.C. Knight, Cell Immunol. 183 (1988) 121-130). Here we derived DC from mouse bone marrow by culture with granulocyte macrophage colony-stimulating factor (GM-CSF) and tumour necrosis factor-alpha (TNF-alpha) for 10-12 days; DC were generated from bone marrow cells taken from normal mice, from mice injected 15 days earlier with RLV or from those receiving RLV plus five daily doses of 100 ng of IL-12 starting 2 days before infection. Infection of the DC with RLV was assessed from nested PCR with doubling dilutions of DNA and the capacity of DC to stimulate a MLR was tested. DC derived from bone marrow of IL-12 treated animals showed at least twice the level of infection with RLV as those from non-treated animals although infection never exceeded 20% of the cells. DC derived from bone marrow of mice given RLV caused negligible stimulation of the MLR but those from mice additionally treated with IL-12 functioned normally. Thus, treatment of mice with IL-12 promoted the potential of stem cells taken 12 days after the last IL-12 injection to develop into functional DC despite increased infection with virus. Treatment of mice with IL-12 may have a long term effect on the potential growth of DC from stem cells which may contribute to the potency of this cytokine in promoting cell mediated immune responses.     

骨髓间充质干细胞及其向肝样细胞分化的潜能

背景：研究表明,在一定条件下骨髓间充质干细胞可诱导分化为肝样细胞,为治疗急性肝衰竭等终末期肝病提供了新的思路。 目的：对骨髓间充质干细胞的发现、分离培养、诱导分化及应用前景等方面做一综述。 方法：计算机检索中国期刊网全文数据库以及PubMed数据库1999至2014年期间有关骨髓间充质干细胞及其向肝样细胞分化的文章。检索词分别为“肝样细胞,骨髓间充质干细胞,细胞分化”和“hepatocyte-like cells,bone marrow mesenchymal stem cells,differentiation”。最后选择52篇文章纳入结果分析。 结果与结论：目前,肝组织工程的首要问题是寻找性状稳定具有肝特异性功能的种子细胞,成熟肝细胞获取难度较大,并具有产生免疫排斥反应、体外培养困难等缺陷,严重限制了肝移植的开展。骨髓间充质干细胞具有多向分化、自我更新快、易于扩增及培养等优点,被认为是最有前途的细胞来源。已有研究表明骨髓间充质干细胞在体内外均可分化为肝细胞,并具有肝细胞的合成和分泌功能。但如何大量扩增此类细胞的同时又能保持其良好的分化潜能、体外培养的最佳条件、诱导分化机制和临床应用的安全性等尚需进一步研究和探讨。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

Hypoxia increases VEGF-A production by prostate cancer and bone marrow stromal cells and initiates paracrine activation of bone marrow endothelial cells

Hypoxia develops at sites of rapid cancer growth near sites of poorly organized vasculature. Heparin binding growth factors (HBGFs) support neoangiogenesis of tumors. We examined the effect of culturing bone-targeted, metastatic C4-2B prostate cancer cells and bone stromal derived HS27a cells under hypoxic conditions on expression of vascular endothelial growth factor (VEGF) family members. A sealed chamber infused with 1% (hypoxic) or 20% (normoxic) O(2) was used. Both cell lines produced VEGF-A in normoxia, but little or no HB-EGF, another HBGF. HS27a cells produced low levels of FGF-2 and HGF, but little or none was secreted by C4-2B cells. Levels of VEGF-A in conditioned medium (CM) from both cell lines doubled when cultured in hypoxia. Similar changes in VEGF-A mRNA levels were seen. Receptor expression was unchanged by hypoxia. Changes in VEGF-A expression during hypoxia were preceded by nuclear accumulation of hypoxia inducible factor-1alpha (HIF-1alpha). Bone marrow endothelial (BME) cells express high levels of VEGFR2/flk-1, and are targets of VEGF-A induced neovascularization. BME cells proliferated in response to treatment with HS27a CM, but not C4-2B CM. BME cells formed tube-like angiogenic structures on growth factor reduced Matrigel in response to CM from HS27a or C4-2B cells. This response was greater when CM was produced under hypoxia, and was reduced by VEGF-A or FGF-2 neutralizing antibodies. We conclude that hypoxia triggers a physiologically relevant increase in VEGF-A by prostate cancer and bone marrow stromal cells which involves a paracrine loop that recruits and activates BME to support tumor neovascularization-related processes.     

Insulin-degrading enzyme deficiency in bone marrow cells increases atherosclerosis in LDL receptor-deficient mice

BackgroundInsulin-degrading enzyme (IDE), a protease implicated in several chronic diseases, associates with the cytoplasmic domain of the macrophage Type A scavenger receptor (SR-A). Our goal was to investigate the effect of IDE deficiency (Ide^?/?) on diet-induced atherosclerosis in low density lipoprotein-deficient (Ldlr^?/?) mice and on SR-A function.MethodsIrradiated Ldlr^?/? or Ide^?/?Ldlr^?/? mice were reconstituted with wild-type or Ide^?/? bone marrow and, 6 weeks later, were placed on a high-fat diet for 8 weeks.ResultsAfter 8 weeks on a high-fat diet, male Ldlr^?/? recipients of Ide^?/? bone marrow had more atherosclerosis, higher serum cholesterol and increased lesion-associated β-amyloid, an IDE substrate, and receptor for advanced glycation end products (RAGE), a proinflammatory receptor for β-amyloid, compared to male Ldlr^?/? recipients of wild-type bone marrow. IDE deficiency in male Ldlr^?/? recipient mice did not affect atherosclerosis or cholesterol levels and moderated the effects of IDE deficiency of bone marrow-derived cells. No differences were seen between Ldlr^?/? and Ide^?/?Ldlr^?/? female mice reconstituted with Ide^?/? or wild-type bone marrow. IDE deficiency in macrophages did not alter SR-A levels, cell surface SR-A, or foam cell formation.ConclusionIDE deficiency in bone marrow-derived cells results in larger atherosclerotic lesions, increased lesion-associated Aβ and RAGE, and higher serum cholesterol in male, Ldlr^?/? mice.     

Intracarotid transplantation of bone marrow stromal cells increases axon-myelin remodeling after stroke

The present study investigates the induction of axon and myelin remodeling as a possible mechanism by which treatment of stroke with bone marrow stromal cells improves neurological functional recovery. Adult male Wistar rats were subjected to 2 h of middle cerebral artery occlusion, followed by an injection of 2 x 10(6) rat bone marrow stromal cells or phosphate-buffered saline into the internal carotid artery 24 h later. Animals were killed at 28 days after stroke. Functional tests, histo- and immunohistochemical staining were performed. Significant functional recovery was found after bone marrow stromal cell administration in all the three tests performed (modified neurological severity score, adhesive-removal and corner tests). Bone marrow stromal cell treatment markedly increased vessel sprouting, synaptophysin expression and NG2 positive cell numbers and density in the cortical peri-infarct area. In bone marrow stromal cell-treated rats, the number of Ki-67 positive proliferating cells and oligodendrocyte precursor cells in the corpus callosum increased significantly in concert with the enhancement of the areas of the corpus callosum in both hemispheres. These results suggest that bone marrow stromal cells facilitate axonal sprouting and remyelination in the cortical ischemic boundary zone and corpus callosum, which may underlie neurological functional improvement caused by bone marrow stromal cell treatment.     

内源性骨髓间充质干细胞与骨折微环境中的相关趋化因子

背景：研究表明,骨髓间充质干细胞定向迁移依赖于损伤局部表达趋化因子与细胞表面相应受体的相互作用。然而,哪些趋化因子在介导骨髓间充质干细胞向骨折部位定向迁移过程中起关键作用,目前尚不清楚。 目的：对内源性骨髓间充质干细胞进行示踪,观察其在骨修复中的作用;检测并筛选出骨折微环境中表达量高且与骨髓间充质干细胞趋化规律相关的因子。 方法：建立C57BL/6小鼠荧光/普通骨髓嵌合体,利用嵌合体动物模型制造胫骨骨折模型,在不同时相点检测骨折部位组织绿色荧光蛋白阳性细胞占所有细胞的比例、来源于骨髓间充质干细胞的成骨细胞占全部成骨细胞的比例,判断来源于骨髓的骨髓间充质干细胞在骨折修复中的作用;利用免疫组化等方法检测骨折部位不同时相点趋化因子的蛋白表达水平。 结果与结论：骨折局部绿色荧光蛋白阳性细胞占所有细胞比例在术后1,5,14 d分别为(3.011±0.911)%,(9.031±0.145)%,(12.064±0.145)%;来源于骨髓间充质干细胞的成骨细胞占全部成骨细胞的50%以上;骨折后各时相点微环境中基质细胞衍生因子1、集落刺激因子、肝细胞生长因子、单核细胞趋化蛋白1、间质金属蛋白酶9有不同程度的表达,粒细胞集落刺激因子无明显表达。基质细胞衍生因子1的表达量相对最高。经相关分析认为：基质细胞衍生因子1在骨折微环境中的表达与骨髓间充质干细胞趋化规律具有相关关系。结果表明骨髓内的骨髓间充质干细胞参与骨折修复并在其中起到了重要作用;基质细胞衍生因子1促进骨髓间充质干细胞的定向趋化并参与骨组织的修复。     

Age-related increases in LPS-stimulated nitric oxide production from cultured rat bone marrow cells

Objective: To understand bone metabolism during senescence, we examined age-related change in nitric oxide (NO) production from bone marrow cells stimulated by lipopolysaccharide (LPS). Methods: We evaluated the age-related change in the NO production and expression of iNOS protein and mRNA of LPS-stimulated bone marrow cells collected from the tibiae of young and retired female and young and retired male rats. In addition, we used flow cytometry to assess changes in the distribution of CD14, a cell surface receptor of LPS. Results: The results revealed that NO production from bone marrow cells stimulated with LPS changed with aging. The NO levels in old rats were significantly higher (P<0.05) than those in young rats. Polymerase chain reaction (PCR) analysis indicated that the LPS-induced expression of iNOS mRNA was augmented in retired rats. Although the distribution pattern of the bone marrow cells was similar between young and retired rats, the percentage of CD14-positive cells in specific populations differed between the age groups. Specifically, in the granule-containing bone marrow cells, the percentage of CD14-positive cells was increased in retired rats. Conclusion: Our results indicate that LPS-stimulated NO production from rat bone marrow cells increased with age and that the difference in responsiveness might be due to changes in the percentage of CD14-positive cells in the bone marrow.     

Hemopoietic stem cells with higher hemopoietic potential reside at the bone marrow endosteum

It is now evident that hemopoietic stem cells (HSC) are located in close proximity to bone lining cells within the endosteum. Accordingly, it is unlikely that the traditional method for harvesting bone marrow (BM) from mice by simply flushing long bones would result in optimal recovery of HSC. With this in mind, we have developed improved methodologies based on sequential grinding and enzymatic digestion of murine bone tissue to harvest higher numbers of BM cells and HSC from the endosteal and central marrow regions. This methodology resulted in up to a sixfold greater recovery of primitive hemopoietic cells (lineage(-)Sca(+)Kit(+) [LSK] cells) and HSC as shown by transplant studies. HSC from different anatomical regions of the marrow exhibited important functional differences. Compared with their central marrow counterparts, HSC isolated from the endosteal region (a) had 1.8-fold greater proliferative potential, (b) exhibited almost twofold greater ability to home to the BM following tail vein injection and to lodge in the endosteal region, and (c) demonstrated significantly greater long-term hemopoietic reconstitution potential as shown using limiting dilution competitive transplant assays.     

Effects of donor age on osteogenic cells of rat bone marrow in vitro

The effect of donor age on the production of bone-like tissue and expression of cellular alkaline phosphatase was examined in cultures of cells obtained from rat bone marrow. Stromal cells were obtained from the bone marrow of young (5-6 weeks) and old (18 months) rats and cultured in vitro. After 28 days in first subculture, the following were quantified: (1) the total number of mineralised nodules and the size distribution of nodules and (2) the density of osteoblasts and osteocytes associated with nodules in histological sections. The doubling times of the cultures and the numbers of cells in cultures which expressed alkaline phosphatase activity were determined in separate experiments. Cells from young cultures produced three times more bone-like nodules than old cultures, although no differences were seen in the size distribution of nodules, or on osteoblast and osteocyte density. Doubling times for both groups were similar. The numbers of alkaline phosphatase (AP) positive cells was reduced by half in old cultures. These data show that this model may be useful for the study of the mechanisms of ageing on osteogenesis, and demonstrate a reduced osteogenic capacity in old cultures. The results suggest that this effect may be due to a reduction in the generation of cells of osteoblast lineage during ageing.     

全骨髓细胞贴壁法分离与培养大鼠骨髓间充质干细胞的多向分化能力

背景：分离培养纯度较高的骨髓间充质干细胞是对其进行深入研究的前提。 目的：观察全骨髓贴壁法分离培养大鼠骨髓间充质干细胞的生物学特征。 方法：选取体质量为80-100 g雄性SD大鼠,采用全骨髓细胞贴壁培养法获取骨髓间充质干细胞。在取材过程中需严格掌握大鼠处死至将细胞悬液放入培养箱内的时间,一般控制在40 min以内。使用基础培养基冲洗骨髓腔时力度适中且在骨髓腔内旋转数次,可使骨髓细胞充分脱落,保证骨髓细胞的获得量。 结果与结论：原代骨髓间充质干细胞为贴壁生长的成纤维样细胞,传代后的细胞形态均一,呈漩涡状排列;第3代骨髓间充质干细胞的生长曲线呈S形,经历3个生长时期：潜伏期、对数生长期和停滞期;流式细胞仪检测骨髓间充质干细胞表面抗原结果示：CD29⁺ 99.45%、CD34⁺1.45%、CD44⁺ 99.52%、CD45⁺1.41%;成骨、成脂诱导分化后,矿化结节被茜素红染成橘红色,脂滴被油红O染成红色。说明骨髓间充质干细胞能向成骨、成脂分化,具有多向分化潜能,符合国际细胞治疗学会间充质及组织干细胞委员会提出的鉴定动物来源骨髓间充质干细胞的最低标准。     

Surface coating of bone marrow cells with N-acetylglucosamine for bone marrow implantation therapy

Bone marrow implantation (BMI) has been performed clinically for the treatment of ischemic cardiovascular diseases. To achieve BMI effectively, accumulation of many bone marrow cells (BMCs) in an infarcted area of the myocardium is important. Previously, we reported that cardiomyocytes show strong interaction with N-acetylglucosamine (GlcNAc) and they can take up GlcNAc-conjugated liposomes. Thus, we examined whether GlcNAc-coated BMCs exhibit strong interaction with cardiomyocytes. The cell surface of BMCs was coated with GlcNAc without causing cell injury by GlcNAc-lipophilic polymers. It was found that the GlcNAc-coated BMCs exhibited strong interaction with cardiomyocytes. At 7 days of coculturing the GlcNAc-coated BMCs with cardiomyocytes, BMC-derived cardiomyocytes were generated. The number of BMC-derived cardiomyocytes was higher following coculture with GlcNAc-coated BMCs than following coculture with uncoated and maltose (MA)-coated BMCs. In this study, we demonstrated that the surface coating of BMCs with GlcNAc can be performed easily by using GlcNAc-lipophilic polymers and that GlcNAc-coated BMCs exhibited strong interaction with cardiomyocytes. Therefore, we think that cell surface coating with GlcNAc would help promote accumulation of BMCs in the infarcted area of the myocardium and that this accumulation would be helpful in the treatment of ischemic cardiovascular diseases with BMI.     

GATA-4过表达增加大鼠骨髓间充质干细胞分化为心肌细胞

目的 研究GATA-4转染骨髓间充质干细胞(MSCs)分化为心肌细胞及表达心肌细胞特异性标志物的能力.方法 分离培养MSCs及心肌细胞(CM).第3代MSCs转染GATA-4基因(MSCGATA-4)并通过实时定量聚合酶链反应(PCR)、Western blot和免疫组化鉴定GATA-4的表达.MSCGATA-4与CM嵌套式共培养1周,通过real-time PCR和Western blot检测其心肌基因BNP、α-actinin和Islet-1的表达,用免疫组化观察α-actinin的表达.与CM混合共培养后1周后,观察MSCs的搏动情况,并用流式细胞仪检测心肌分化率.结果 MSCGATA-4组GATA-4的表达明显高于对照组(只表达GFP).MSC与CM嵌套式共培养后,MSCGATA-4组的BNP、α-actinin和Islet-1的mRNA和蛋白表达明显高于对照组(P＜0.05).混合共培养后,可见部分MSCGATA-4的搏动,同时部分MSC的α-actinin染色阳性.用流式细胞仪检测心肌分化率,MSCGATA-4组的心肌分化率明显高于对照组(P＜0.05).结论 GATA-4过表达可以增加MSCs分化成心肌样细胞,高表达BNP、α-actinin和Islet-1.     

Collagen as an immobilization vehicle for bone marrow stromal cells enriched with osteogenic potential

The bone marrow contains mesenchymal cells that can be divided into two categories: cells of hemopoietic lineage and stromal cells. The stromal cells are adhesive to the surface of culture dish, and could be differentiated into cells with bone-forming capability when stimulated with osteogenic supplements. In this study, we have employed collagen to immobilize cells with osteogenic potential from bone marrow. A more than two-fold increase in cell density was obtained on the collagen-coated substratum as compared to the uncoated ones. The selected marrow cells exhibited elevated alkaline phosphatase activity in parallel with the proliferation of the cells attached to the collagen surface. The osteoblastic expression of the selected cells was further confirmed by the histological stains of alkaline phosphatase and mineral deposit. This method provides a simple and fast screening technique to isolate osteoprogenitor-enriched population from the bone marrow stromal cells. It has a great potential for future biological and clinical applications.     

Variations in the histologic distribution of rat bone marrow cells with respect to age and anatomic site

Bone marrow cellularity in untreated Fischer 344/N rats was subjectively evaluated in hematoxylin and eosin (H & E)-stained histologic sections from femur, tibia, humerus, sternum, lumbar vertebrae, ribs, pelvis, and skull of 2-, 4-, 7-, 16-, and 24-month-old males. Marrow cellularity varied with age of the rat and bone site sampled. Hematopoietic cellularity was consistently higher in rats less than 4 months of age and less consistently higher in 24-month-old rats versus intermediate age groups examined. The 24-month-old rats had the greatest animal-to-animal variation in cellularity. Site differences in bone marrow cellularity were present and similar at 4, 7, and 16 months. Mean percentage of marrow space occupied by hematopoietic cells ranged from 33-75%. Categories for histologic grading of bone marrow cellularity are presented. Sternum, femur, and humerus are recommended sites for histologic evaluation of bone marrow cellularity from conventional H & E-stained sections. Definitive evaluation and assessment of hematopoietic perturbations should not be solely based on subjective evaluation of routine histologic sections.     

Effect of age and gender on recovery after stroke in rats treated with bone marrow mononuclear cells

Stroke is a disease of the elderly. However, most of the preclinical studies about the treatment of stroke with bone marrow-derived cells have used young animals. Here, it was assessed whether the sensorimotor recovery promoted by the treatment of the brain ischemia with the bone marrow mononuclear cells (BMMCs) is influenced by age and/or gender. Unilateral cortical ischemia by thermocoagulation was made in the primary motor and sensorimotor cortices in young and middle-aged rats of both genders. Twenty four hours after ischemia, animals received intravenous injection of BMMCs or vehicle. Each combination of age and gender received BMMCs from donor with the same combination. Survival rate and ischemic lesion size were quantified. Sensorimotor recovery was evaluated by the cylinder and adhesive tests. The results showed that the treatment with BMMCs resulted in sensorimotor recovery of both young and middle-aged ischemic rats. No important effect of gender was found, but age was a significant factor. Middle-aged animals had increased mortality and lesion sizes. In the adhesive test, middle-aged animals had lower BMMCs-induced sensorimotor recovery. The results suggest that the treatment of stroke with the BMMCs should be beneficial for males and females in the elderly.     

Efficient thymic immigration of B220+ lymphoid-restricted bone marrow cells with T precursor potential

Using a human CD25 reporter transgene controlled by regulatory sequences from the gene encoding pre-T cell receptor alpha, we identified a common lymphocyte precursor (CLP-2) population that, in contrast to the previously identified CLP-1 population, was c-Kit-B220+. In short-term culture, the CLP-2 could be derived from the CLP-1 subset, and contained cells that in clonogenic assays were assessed to be bipotent precursors of T and B cells. Intravenous injection of bone marrow cells yielded a selective accumulation of CLP-2 thymic immigrants that in thymic organ culture generated mature alphabeta T cells. Although the CLP-2 subset may represent the most differentiated population with T cell potential before commitment to the B cell lineage, other subsets of thymic immigrants capable of generating T cells may exist.     

人骨髓间质干细胞向造血细胞分化潜能的实验研究

目的:在体研究人骨髓间质干细胞(hBMMSCs)向造血细胞分化的潜能。方法:将hBMMSCs经尾静脉注射给环磷酰胺处理的严重联合免疫缺陷(SCID)小鼠,利用流式激活细胞分析系统(FACS)检测hBMMSCs输注后存活35d的SCID小鼠外周血、骨髓和脾脏中人源性造血细胞的表型和水平。结果:hBMMSCs输注组外周血(PB)、骨髓(BM)和脾脏(spleen)中可检测到人CD45⁺/H-2D^d-、CD34⁺/H-2D^d-细胞,而对照组PB、BM和脾脏均未检测到上述表型的人造血细胞。结论:hBMMSCs具有向造血细胞分化的潜能。     

放射抑制小鼠骨髓间充质干细胞成骨潜能并导致骨损伤

目的 观察放射对小鼠骨髓间充质干细胞(BMMSCs)体外成骨潜能及体内骨组织的影响.方法 分离、培养正常的及接受4Gy放射后28d的小鼠BMMSCs,用碱性磷酸酶(ALP)和Von Kossa染色法鉴定BMMSCs体外成骨分化潜能的改变,并通过骨组织形态学和骨密度(BMD)检测放射后小鼠体内骨组织的相关变化.结果 4Gy照射28d后小鼠BMMSCs的成骨潜能明显降低,同时体内骨组织结构破坏,小鼠骨密度降低.结论 放射损伤后小鼠BMMSCs的成骨潜能显著降低,可能在干细胞水平参与了放射后骨损伤的发生.