Bone marrow-derived myofibroblasts contribute functionally to scar formation after myocardial infarction

Myofibroblasts play a major role in scar formation during wound healing after myocardial infarction (MI). Their origin has been thought to be interstitial cardiac fibroblasts. However, the bone marrow (BM) can be a source of myofibroblasts in a number of organs after injury. We have studied the temporal, quantitative and functional role of BM-derived (BMD) myofibroblasts in myocardial scar formation. MI was induced by permanent coronary artery ligation in mice reconstituted with EGFP or pro-Col1A2 transgenic BM. In the latter, luciferase and beta-galactosidase transgene expression mirrors that of the endogenous pro-collagen 1A2 gene, which allows for functional assessment of the recruited cells. After MI, alpha-SMA-positive myofibroblasts and collagen I gradually increased in the infarct area until day 14 and remained constant afterwards. Numerous EGFP-positive BMD cells were present during the first week post-MI, and gradually decreased afterwards until day 28. Peak numbers of BMD myofibroblasts, co-expressing EGFP and alpha-SMA, were found on day 7 post-MI. An average of 21% of the BMD cells in the infarct area were myofibroblasts. These cells constituted up to 24% of all myofibroblasts present. By in vivo IVIS imaging, BMD myofibroblasts were found to be active for collagen I production and their presence was confined to the infarct area. These results show that BMD myofibroblasts participate actively in scar formation after MI.     

Bone marrow-derived cells contribute to epithelial engraftment during wound healing

Recent findings suggest that bone marrow-derived cells (BMDC) may contribute to tissue maintenance throughout the body. However, it is not yet known whether marrow-derived epithelial cells are capable of undergoing proliferation. Our laboratory has shown that BMDC engraft as keratinocytes in the skin at low levels (相似文献   

Lymphangiogenesis in myocardial remodelling after infarction

AIMS: The lymphatic system is involved in fluid homeostasis of the cardiac interstitium, but lymphangiogenesis in myocardial remodelling has not previously been examined histopathologically. The aim was to investigate by D2-40 immunohistochemistry the sequential changes in lymphatic distribution in the process of myocardial remodelling after myocardial infarction (MI). METHODS AND RESULTS: Myocardial tissues in various phases of healing after MI were obtained from 40 autopsied hearts. D2-40+ lymphatic vessel density (LD) and CD34+ blood vessel density (BD) in the lesion were determined. BD decreased with advance of myocardial necrosis, subsequently increased at the early stage of granulation and thereafter decreased with the progression of scar formation. In contrast, lymphatic vessels were not detected in lesions with coagulation necrosis, and newly formed lymphatics first appeared in the early stages of granulation. A subsequent increase in LD was demonstrated in the late stages of granulation, and lymphatics remained up to the scar phase. Vascular endothelial growth factor-C was consistently expressed in viable cardiomyocytes around the lesion in all of these stages. CONCLUSION: In myocardial remodelling after MI, lymphangiogenesis lags behind blood vessel angiogenesis; newly formed lymphatics may be involved mainly in the maturation of fibrosis and scar formation through the drainage of excessive proteins and fluid.     

骨髓间充质干细胞在急性心肌梗死后心室重构中的应用☆

背景：动物实验和初期的临床研究表明,干细胞移植可以取代坏死心肌细胞、增加有功能心肌细胞的数量,改善心功能,从而为心肌梗死的治疗开辟了一条崭新的途径。 目的：观察心肌梗死后自体骨髓间充质干细胞移植及骨髓动员对心功能的影响。 方法：经猪髂前上棘抽取骨髓30 mL,培养得到骨髓间充质干细胞。15只猪分为3组,模型组仅建立心肌梗死模型,干细胞移植组在造模3 h后经冠状动脉注射骨髓间充质干细胞,干细胞动员组在造模3 h后连续5 d注射粒细胞集落刺激因子    150 μg/(kg•d)。 结果与结论：心肌梗死后8周,干细胞动员组、干细胞移植组左心室收缩、舒张末期内径都明显减小,射血分数较心肌梗死前提高,但差异无显著性意义(P > 0.05);干细胞动员组及干细胞移植组血清血管内皮生长因子水平较心肌梗死前有上升趋势(P < 0.05);干细胞动员组和干细胞移植组梗死交界区的毛细血管密度均大于模型组(P < 0.05)。提示心肌梗死后行自体骨髓间充质干细胞移植及骨髓动员均能明显改善心功能,但具体效果仍需进一步大样本实验研究。 关键词：缺血性心脏病;心力衰竭;骨髓间充质干细胞;血管再生;粒细胞集落刺激因子 doi:10.3969/j.issn.1673-8225.2012.10.009     

Bone marrow-derived cells contribute to cerulein-induced pancreatic fibrosis in the mouse

Bone marrow (BM) cells may transdifferentiate into circulating fibrocytes and myofibroblasts in organ fibrosis. In this study, we investigated the contribution and functional roles of BM-derived cells in murine cerulein-induced pancreatic fibrosis. C57/BL6 female mice wild-type (WT) or Col 1α1(r/r) male BM transplant, received supraphysiological doses of cerulein to induce pancreatic fibrosis. The CD45(+)Col 1(+) fibrocytes isolated from peripheral blood (PB) and pancreatic tissue were examined by in situ hybridization for Y chromosome detection. The number of BM-derived myofibroblasts, the degree of Sirius red staining and the levels of Col 1α1 mRNA were quantified. The Y chromosome was detected in the nuclei of PB CD45(+)Col 1(+) fibrocytes, confirming that circulating fibrocytes can be derived from BM. Co-expression of α-smooth muscle actin illustrated that fibrocytes can differentiate into myofibroblasts. The number of BM-derived myofibroblasts, degree of collagen deposition and pro-collagen I mRNA expression were higher in the mice that received Col 1α1(r/r) BM, (cells that produce mutated, collagenase-resistant collagen) compared to WT BM, indicating that the genotype of BM cells can alter the degree of pancreatic fibrosis. Our data indicate that CD45(+)Col 1(+) fibrocytes in the PB can be BM-derived, functionally contributing to cerulein-induced pancreatic fibrosis in mice by differentiating into myofibroblasts.     

Bone marrow-derived cells contribute to cell turnover in aging murine hearts

The paradigm that cardiac myocytes are non-proliferating, terminally differentiated cells was recently challenged by studies reporting the ability of bone marrow-derived cells (BMCs) to differentiate into cardiomyocytes after myocardial damage. However, little knowledge exists about the role of BMCs in the heart during physiological aging. Twelve-week-old mice (n=36) were sublethally irradiated and bone marrow from littermates transgenic for enhanced green fluorescent protein (eGFP) was transplanted. After 4 weeks, 18 mice were sacrificed at the age of 4 months and served as controls (group A); the remaining mice were sacrificed at the age of 18 months (group B). Group A did not exhibit a significant number of eGFP+ cells, whereas 9.4±2.8 eGFP+ cells/mm2 was documented in group B. In total, only five eGFP+ cardiomyocytes were detected in 20 examined hearts, excluding a functional role of BM differentiation in cardiomyocytes. Similarly, a relevant differentiation of BMCs in endothelial or smooth muscle cells was excluded. In contrast, numerous BM-derived fibroblasts and myofibroblasts were observed in group B, but none were detected in group A. The present study demonstrates that BMCs transdifferentiate into fibroblasts and myofibroblasts in the aging murine myocardium, suggesting their contribution to the preservation of the structural integrity of the myocardium, while they do not account for regenerative processes of the heart.     

双特异抗体增效内皮祖细胞移植促进心肌血管新生

目的探讨在双特异抗体(BiAb)的辅助下,内皮祖细胞(EPCs)移植可否更好的定向归巢大鼠缺血心肌促进血管新生。方法体外分离培养鉴定SD大鼠骨髓源性内皮祖细胞;开胸结扎SD大鼠冠状动脉左前降支制备心肌梗死模型;以anti-CD34(能识别内皮祖细胞)和抗肌凝蛋白轻链抗体(AMLCA)(能特异性结合缺血心肌)2种抗体,化学交联法制备BiAb(CD34×AMLCA)。将此BiAb与EPCs经尾静脉输入心肌梗死大鼠(EPCs+BiAb组),另设单纯EPCs移植组、单纯BiAb组、对照组。细胞移植35 d后M型超声心动图检测大鼠左室收缩功能,免疫组织化学法行5-Brdu及VIII因子检测,实时荧光定量PCR及Western blot检测大鼠心肌VEGF mRNA与蛋白表达。结果与其余组相比,EPCs+BiAb组射血分数及短轴缩短率增加,心梗区周围5-BrdU阳性细胞数及微血管密度增加,心肌VEGF mRNA与蛋白表达增加(P<0.05)。结论 CD34×AMLCA双特异抗体可增效大鼠骨髓源性内皮祖细胞定向归巢到大鼠缺血心肌,改善心功能,更好的促进血管新生。     

Bone marrow-derived progenitor cells do not contribute to podocyte turnover in the puromycin aminoglycoside and renal ablation models in rats

A key event in the progression of glomerular disease is podocyte loss that leads to focal and segmental glomerulosclerosis (FSGS). Because adult podocytes are postmitotic cells, podocyte replacement by bone marrow-derived progenitors could prevent podocytopenia and FSGS. This study uses double immunofluorescence for Wilms' tumor-1 and enhanced green fluorescent protein (eGFP) to examine whether an eGFP-positive bone marrow transplant can replace podocytes under normal circumstances and in 3 different rat models of FSGS: puromycin aminoglycoside nephropathy, subtotal nephrectomy, and uninephrectomy. Bone marrow engraftment was successful, with more than 70% eGFP-positive cells and virtually normal histologic findings. No bone marrow transplant-derived podocytes were found in four control rats after transplantation, in nine rats at up to 10 weeks after puromycin aminoglycoside nephropathy induction, in three rats 23 days after subtotal nephrectomy, and in six rats up to 21 days after uninephrectomy. A total of 2200 glomeruli with 14,474 podocytes were evaluated in all groups. Thus, podocyte replacement by bone marrow-derived cells does not contribute to podocyte turnover in rats, even in models of podocyte damage. This is in contrast to previous studies in mice, in which bone marrow-derived podocytes were found. Further studies will address this discrepancy, which could be explained by species differences or by predominant podocyte regeneration from a parietal epithelial cell niche.     

大鼠心肌匀浆上清液对骨髓间质干细胞诱导分化的影响

目的：探讨心肌匀浆上清液对大鼠骨髓间质干细胞（MSCs）诱导分化的影响。 方法： 体外分离培养大鼠MSCs，检测纯度。于原代培养第3 d加入自体心肌匀浆上清液持续作用1周。3周后，观察细胞形态，采用免疫细胞化学检测肌球蛋白重链和心肌特异性肌钙蛋白-T，RT-PCR方法检测Nkx2.5、α-MHC和ANP基因的表达。 结果： 大鼠MSCs经诱导后，表达肌球蛋白重链、心肌特异性肌钙蛋白-T和Nkx2.5、α-MHC基因，但未表达ANP基因，也未观察到肌管和闰盘样结构。 结论： 心肌匀浆上清液对MSCs具有定向诱导分化作用，但诱导不完全，具体机制仍需深入研究。     

Bone marrow-derived mononuclear cells vs. mesenchymal stromal cells in experimental allergic asthma

We compared the effects of bone marrow-derived mononuclear cells (BMMCs) and mesenchymal stromal cells (MSCs) on airway inflammation and remodeling and lung mechanics in experimental allergic asthma. C57BL/6 mice were sensitized and challenged with ovalbumin (OVA group). A control group received saline using the same protocol. Twenty-four hours after the last challenge, groups were further randomized into subgroups to receive saline, BMMCs (2 × 10⁶) or MSCs (1 × 10⁵) intratracheally. BMMC and MSC administration decreased cell infiltration, bronchoconstriction index, alveolar collapse, collagen fiber content in the alveolar septa, and interleukin (IL)-4, IL-13, transforming growth factor (TGF)-β and vascular endothelial growth factor (VEGF) levels compared to OVA-SAL. Lung function, alveolar collapse, collagen fiber deposition in alveolar septa, and levels of TGF-β and VEGF improved more after BMMC than MSC therapy. In conclusion, intratracheal BMMC and MSC administration effectively modulated inflammation and fibrogenesis in an experimental model of asthma, but BMMCs was associated with greater benefit in terms of reducing levels of fibrogenesis-related growth factors.     

急性心肌梗死大鼠趋化因子表达与心功能的关系

目的：探讨急性心肌梗死（AMI）大鼠心肌局部趋化因子的表达与淋巴细胞浸润及心功能的关系。 方法： 结扎冠状动脉左前降支建立AMI大鼠模型，实验动物分为3组：心衰组（MI-HF）、未心衰组(MI-NF)和假手术组(sham)，假手术组只过线不结扎。于术后3 d、1周、2周检测血流动力学，将左室舒张末期压力(LVEDP)≥15 mmHg者归为心衰组。用半定量RT-PCR方法测定心肌梗死区（包括梗死周边区）趋化因子的mRNA表达，包括γ干扰素诱导的单核因子（MIG）、巨噬细胞炎性蛋白-1α（MIP-1α）、正常T细胞表达和分泌、活化时表达下降的因子（RANTES）。HE染色切片进行梗死区淋巴细胞计数分析。 结果： AMI大鼠心肌局部趋化因子的mRNA表达于术后3 d开始升高，1周达峰值，且MI-HF组较MI-NF组表达更高(RANTES, 0.83±0.05 vs 0.51±0.19, P<0.05; MIP-1α, 1.94±0.30 vs 1.48±0.33, P<0.05; MIG, 1.40±0.27 vs 0.93±0.28, P<0.05)。RANTES和MIP-1α的表达与淋巴细胞浸润显著相关(RANTES，r=0.35，P<0.05；MIP-1α，r＝0.40，P<0.05)。 结论： AMI后心肌局部趋化因子RANTES、MIP-1α、MIG表达增高，且趋化因子水平与心功能有相关性，趋化因子可能参与了AMI后心衰的病理生理学发展过程。     

小型猪外周血内皮祖细胞的体外培养与分化研究

目的：研究小型猪外周血内皮祖细胞（EPC）的体外分离和定向分化、扩增培养方法，为EPC移植应用于临床提供实验依据。 方法： 密度梯度离心法从小型猪200 mL新鲜全血中分离单个核细胞，用含血管内皮生长因子等各种添加剂的内皮细胞系列专用培养液，分别在包被与不包被的培养皿中进行贴壁培养，诱导其向内皮细胞分化，观察经过不同时间培养后的细胞生长情况并进行诱导分化后的生物学鉴定，包括细胞表型鉴定、DiI标记的乙酰化低密度脂蛋白（DiI-acLDL）摄取试验、超微结构鉴定、体外血管生成实验。 结果： 包被了贴壁因子的培养皿细胞贴壁及增殖均多于未包被组。前者第3-4 d可观察到梭形贴壁细胞，10 d后出现多个细胞簇，14 d左右可观察到条索状、网状血管样结构，原代细胞培养21 d左右接近融合并且呈典型的鹅卵石样排列。第7-14 d有大于98%的细胞Flk-1、vWF、CD31表达阳性，CD34+细胞为（26.01±2.82）％，有大于95%的细胞DiI-acLDL摄取试验阳性，透射电镜可见特征性的Weible-Palade小体存在，在血管生成实验中，血管内皮生长因子显著促进EPC形成小管的数量与复杂程度，呈一定的量效关系。 结论： 密度梯度离心法结合贴壁筛选培养法可以用于体外分离外周血中EPC进行实验研究，EPC在一定的诱导培养条件下能分化成为血管内皮细胞，贴壁因子、血管内皮生长因子等对于体外培养EPC有很重要的作用。     

小鼠骨髓多能成体祖细胞的分离、培养及体外诱导分化为胰岛素分泌细胞的研究

目的：探讨培养骨髓多能成体祖细胞的条件和生物学特性及其向胰岛素分泌细胞分化的可能性。 方法： 采用文献报道的条件培养液培养小鼠骨髓多能成体祖细胞，观察其细胞形态、生长情况、细胞表面标志及mRNA水平，检测其oct-4基因表达，并以含胰高糖素多肽-1的无血清培养液诱导分化细胞，基因水平检测与胰岛素分泌细胞有关的基因表达。 结果： 小鼠骨髓多能成体祖细胞类圆形，细胞核大，胞质少；细胞增殖能力尚可；细胞表面CD13+、CD44-、CD45-、MHCⅡ-；有oct-4基因表达；诱导分化后，可见与胰岛素分泌细胞有关的基因表达。 结论： 成功培养小鼠骨髓多能成体祖细胞，具有与文献报道类似的生物学特征；有被诱导分化为胰岛素分泌细胞的可能性。     

大黄素对心肌梗死后心力衰竭大鼠心肌保护机制研究

目的 探讨大黄素对心肌梗死后心力衰竭大鼠心肌细胞能量代谢的作用及其对细胞外信号调节激酶（extra-cellular signal regulated kinase,ERK）信号的调节机制。方法 采用结扎左前降支的方法构建大鼠心肌梗死模型,将动物模型按照随机数字表法分为模型组、低剂量组、中剂量组、高剂量组以及对照组,每组10只;同时另取10只大鼠作为假手术组,假手术组动物在造模术中只进行穿线,不结扎;低剂量组、中剂量组、高剂量组大鼠每日分别以20、40、60 mg/kg大黄素灌胃,对照组以10 mg/kg卡托普利灌胃处理,连续给药14 d,统计分析各组大鼠的左室射血分数（left ventricular ejection fraction,LVEF）、左室收缩期末内径（left ventricular end-systolic diameter,LVESD）、左室舒张期末内径（left ventricular end-diastolic diameter,LVEDD）、室间隔厚度（interventricular septum thickness,IVS）等心功能的变化,TUNEL染色...