Distribution of myocardial macrophages in the normal human heart

Macrophages are important in inflammatory processes in heart disease and in transplantation rejection. A resurgence of interest in the macrophage has emanated from recent evidence implicating it as an effector cell in atherosclerosis and transplantation rejection. The detailed distribution of the macrophage within the normal human heart is unknown. We quantified macrophage numbers in the different chambers of the heart. Large tissue blocks (1.5–2.0 cm³) were removed from specific sites in 5 'normal' control hearts (2 males, 3 females, age range 19–46 y). Paraffin-embedded sections were stained with a CD68 pan macrophage marker. Positive cells were enumerated within 20 random fields. Results were analysed using a generalised linear modelling method using the Poisson distribution. Macrophages were identified within septa, and often close to blood vessels, in the myocardium, and in the majority of areas in all hearts. Macrophage numbers varied significantly between areas (range 0–6 cells/high power field; P <0.001), and between the 5 hearts analysed ( P <0.001). In general, there were significantly more macrophages in the ventricles (RV P <0.01, LV P <0.05), but these differences were affected by heart differences. This study provides a baseline for the range of macrophage numbers within normal hearts, thus enabling comparisons with macrophage numbers within diseased and transplanted hearts.     

组织定居巨噬细胞在肿瘤微环境中的作用

肿瘤相关巨噬细胞(tumor-associated macrophages,TAMs)是肿瘤微环境中最主要的免疫细胞群之一,在肿瘤生长、血管生成和治疗等各环节发挥重要作用。以往研究认为肿瘤微环境中TAMs主要来源于循环单核细胞,但近期研究证实,起源于胚胎卵黄囊及胎肝的组织定居巨噬细胞也可以在肿瘤微环境中分化为TAMs,...     

The roles of blood-derived macrophages and resident microglia in the neuroinflammatory response to implanted Intracortical microelectrodes

Resident microglia and blood-borne macrophages have both been implicated to play a dominant role in mediating the neuroinflammatory response affecting implanted intracortical microelectrodes. However, the distinction between each cell type has not been demonstrated due to a lack of discriminating cellular markers. Understanding the subtle differences of each cell population in mediating neuroinflammation can aid in determining the appropriate therapeutic approaches to improve microelectrode performance. Therefore, the goal of this study is to characterize the role of infiltrating blood-derived cells, specifically macrophages, in mediating neuroinflammation following intracortical microelectrode implantation. Interestingly, we found no correlation between microglia and neuron populations at the microelectrode-tissue interface. On the other hand, blood-borne macrophages consistently dominated the infiltrating cell population following microelectrode implantation. Most importantly, we found a correlation between increased populations of blood-derived cells (including the total macrophage population) and neuron loss at the microelectrode-tissue interface. Specifically, the total macrophage population was greatest at two and sixteen weeks post implantation, at the same time points when we observed the lowest densities of neuronal survival in closest proximity to the implant. Together, our results suggest a dominant role of infiltrating macrophages, and not resident microglia, in mediating neurodegeneration following microelectrode implantation.     

Crystalloid inclusions in brain macrophages and hemopoietic tissue in GFAP-IL3 mice resemble inclusions identified in multiple sclerosis

Crystalloid inclusions or "pole bodies" observed in brain macrophages in human demyelinating disease represent a morphological enigma. Similar inclusions were detected in brain macrophages from the GFAP-IL3 mouse, a transgenic murine model for macrophage mediated demyelination. Mice also showed inclusions in hematopoietic tissue. They appear to be related to phagocytosis and secretion, respectively, as evidenced by the fact that in phagocytosing cells they often merged with lysozomes and that affected cells showed empty channels open to the interstitium. Based on ultrastructural and immunolocalization studies using chaperonin-10, lysozyme, and cathepsin the authors suggest that these inclusions are consistent with phagocytosis-related secretory products. This study may provide insight into the nature and significance of similar macrophage inclusions recently identified in multiple sclerosis.     

Interkeukin‐34, a cytokine crucial for the differentiation and maintenance of tissue resident macrophages and Langerhans cells

IL‐34 is a recently discovered cytokine that acts on tissue resident macrophages and Langerhans cells upon binding the receptor for CSF‐1, CSF‐1R. The existence of two ligands for CSF‐1R, IL‐34, and CSF‐1, raises several intriguing questions. Are IL‐34 and CSF‐1 redundant or does each perform temporally and spatially distinct functions? Is IL‐34 involved in human pathology? Would therapeutic strategies based on selective inhibition or administration of either IL‐34 or CSF‐1 be advantageous for preventing human pathology? Recent in vivo studies indicate that IL‐34 promotes the development, survival, and function of microglia and Langerhans cells; therefore, this cytokine may predominately function in brain and skin biology. Here, we review the evidence for IL‐34 as a key cytokine in the development and function of these two diverse cell types and discuss its potential role in pathological conditions.     

Metabolism of tissue macrophages in homeostasis and pathology

Cellular metabolism orchestrates the intricate use of tissue fuels for catabolism and anabolism to generate cellular energy and structural components. The emerging field of immunometabolism highlights the importance of cellular metabolism for the maintenance and activities of immune cells. Macrophages are embryo- or adult bone marrow-derived leukocytes that are key for healthy tissue homeostasis but can also contribute to pathologies such as metabolic syndrome, atherosclerosis, fibrosis or cancer. Macrophage metabolism has largely been studied in vitro. However, different organs contain diverse macrophage populations that specialize in distinct and often tissue-specific functions. This context specificity creates diverging metabolic challenges for tissue macrophage populations to fulfill their homeostatic roles in their particular microenvironment and conditions their response in pathological conditions. Here, we outline current knowledge on the metabolic requirements and adaptations of macrophages located in tissues during homeostasis and selected diseases.     

Time‐lapse microscopy of macrophages during embryonic vascular development

Background : Macrophages are present before the onset of blood flow, but very little is known about their function in vascular development. We have developed a technique to concurrently label both endothelial cells and macrophages for time‐lapse microscopy using co‐injection of fluorescently conjugated acetylated low‐density lipoprotein (AcLDL) and phagocytic dye PKH26‐PCL. Results : We characterize double‐labeled cells to confirm specific labeling of macrophages. Double‐labeled cells circulate, roll along the endothelium, and extravasate from vessels. Most observed macrophages are integrated into the vessel wall, showing an endothelial‐like morphology. We used transgenic quail that express a fluorescent protein driven by the endothelial‐specific promoter Tie1 in conjugation with the phagocytic dye to analyze these cells. Circulating PKH26‐PCL‐labeled cells are mostly Tie1?, but those which have integrated into the vessel wall are largely Tie1+. The endothelial‐like phagocytic cells were generally stationary during normal vascular development. We, therefore, induced vascular remodeling and found that these cells could be recruited to sites of remodeling. Conclusions : The active interaction of endothelial cells and macrophages support the hypothesis that these cells are involved in vascular remodeling. The presence of phagocytic endothelial‐like cells suggests either a myeloid‐origin to certain endothelial cells or that circulating endothelial cells/hematopoietic stem cells have phagocytic capacity. Developmental Dynamics 241:1423–1431, 2012. © 2012 Wiley Periodicals, Inc.     

Inflammation in tissue engineering: The Janus between engraftment and rejection

Tissue engineering (TE) for tissue and organ regeneration or replacement is generally performed with scaffold implants, which provide structural and molecular support to in vitro seeded or in vivo recruited cells. TE implants elicit the host immune response, often resulting in engraftment impediment or rejection. Besides this negative effect, however, the immune system components also yield a positive influence on stem cell recruitment and differentiation, allowing tissue regeneration and healing. Thus, a balanced cooperation between proinflammatory and proresolution players of the immune response is an essential element of implant success. In this context, macrophage plasticity plays a fundamental role. Therefore modulating the immune response, instead of immune suppressing the host, might be the best way to successfully implant TE tissues or organs. In particular, it is becoming evident that the scaffold, immune, and stem cells are linked by a three‐way interaction, and many efforts are being made for scaffold‐appropriate design and functionalization in order to drive the inflammation process toward regeneration, vascularization, and implant success. This review discusses current and potential strategies for inflammation modulation to aid engraftment and regeneration, supporting the concept that quality, and not quantity, of inflammation might influence implant success.     

巨噬细胞对肿瘤细胞结合与杀伤功能的研究——带瘤鼠和正常鼠腹腔巨噬细胞结合与杀伤功能的比较

M_φ介导的对肿瘤细胞的杀伤过程主要分三个步骤:(a)体内或体外对M_φ的激活;(b)效应细胞与靶细胞的紧密接触、即结合;(c)靶细胞的溶解,即效应细胞对靶细胞的杀伤。一般认为,效应细胞与靶细胞的结合是杀伤的先决条件。在肿瘤发     

创伤后巨噬细胞抑制T细胞功能的分子机制研究

目的：研究创伤后巨噬细胞掏细胞功能的分子机制。方法：将创伤小鼠的巨噬细胞,加入至正常小鼠Ｔ细胞培养系统中,测定Ｔ细胞功能及细胞内信使分子。结果：创伤后巨噬细胞在体外可明显抑制经ＣｏｎＡ刺激的正常Ｔ淋巴细胞转化、白介素２（ＩＬ－２）的生成、ＩＬ－２受体α（ＩＬ－２α）的表达以及ＩＬ－２ｍＲＮＡ、ＩＬ－２ＲαｍＲＮＡ水平,可升高正常活化Ｔ细胞内ｃＡＭＰ含量,降低ｃＧＭＰ含量、游离钙（〖Ｃａ＾２＋〗ｉ浓     

三种免疫抑制药对分化的巨噬细胞表型和功能的影响

目的 探讨3种免疫抑制药(雷帕霉素、环孢霉素A和紫杉醇)在骨髓前体细胞分化过程中对分化的巨噬细胞表型和功能的影响.方法 取60只C57BL/6小鼠颈椎脱臼致死,无菌操作制备骨髓前体细胞,在细胞培养体系中分别加入雷帕霉素(100μmol/L)、环孢霉素A(1mg/L)和紫杉醇(20μg/L)和巨噬细胞集落刺激因子,通过混...     

P物质对小鼠腹腔巨噬细胞功能的调整作用

本文研究了神经肽P物质(Substance P,SP)对经硫代乙醇酸钠(TG)培基活化的小鼠腹腔巨噬细胞(Mφ)的免疫功能的影响。结果表明,经TG活化的Mφ在体外与SP共同培养18小时后,其吞噬中性红的能力明显提高,其有效浓度在10~(-6)～10~(-8)M之间(P<0.05)。实验中还发现SP在10~(-7)～10~(-9)M有显著增强Mφ产生IL-1的作用,SP与LPS(10μg/ml)联合应用可协同促进IL—1的产生。SP尚可增强Mφ对肿瘤细胞增殖的抑制作用,但这一作用较巨噬细胞活化因子(MAF)明显为弱。SP不能与Con A协同增强小鼠脾脏T细胞产生MAF的能力。     

巨噬细胞活化因子的双相效应及巨噬细胞的促瘤细胞生长作用

PHA刺激的人扁桃体T细胞分泌的淋巴因子中含有的MAF,可使TG活化Mφ表达达促进或抑制瘤细胞生长的双相作用。30例样品的分析结果提示,该相反的两种作用是由不同的MAF分子诱导所致,TG活化Mφ能分泌促瘤细胞生长因子,此因子不是IL—1,不能增强小鼠脾脏T细胞的增殖,MAF可抑制TG活化Mφ分泌促瘤细胞生长因子的能力。     

双顺反子表达人组织因子途径抑制因子和绿色荧光蛋白重组病毒的构建及其在内皮祖细胞中表达

目的 构建双顺反子表达人组织因子途径抑制因子（TFPI）与绿色荧光蛋白（GFP）的逆转录病毒表达载体pMSCV-TFPI-IRES-GFP,并观察其在大鼠内皮祖细胞（EPCs）中的表达,为进一步研究TEPI在预防血管再狭窄中的作用奠定基础.方法 将人全长TFPI cDNA亚克隆到逆转录病毒载体pMSCV-IRES-GFP中,获得定向插入重组子pMSCV-TFPI-IRES-GFP,采用酶切图谱分析和测序进行鉴定.用磷酸钙法经293T细胞包装,收集病毒上清,感染EPCs.用荧光显微镜和流式细胞术观察感染后细胞内GFP表达情况.RT-PCR检测EPCs中TFPI mRNA的表达水平,ELISA法检测EPCs细胞培养上清中TFPI蛋白的含量.结果 经限制性内切酶酶切图谱分析证实重组病毒中含有人TFPI的cDNA片段,基因测序结果与Genebank中TFPI cDNA序列相符.荧光显微镜观察及流式细胞仪检测显示,90%以上的感染细胞中存在GFP表达;RT-PCR分析显示,重组病毒感染细胞中TFPI mRNA水平明显增高;ELISA法检测发现,感染重组病毒的EPCs培养上清中有TFPI蛋白表达.结论 本研究成功构建重组pMSCV-TFPI-IRES-GFP真核表达载体,其在EPCs中能够同时表达TFPI和GFP,为TFPI基因结合血管内皮祖细胞进行血管再狭窄防治研究的进一步深入开展奠定了良好实验基础.     

重度烫伤小鼠血清及去补体后血清诱导巨噬细胞凋亡作用的体外实验研究

目的　探讨重度烫伤小鼠血清及去补体血清在体外诱导腹腔巨噬细胞 (pMФs)凋亡及其机制。方法　采用小鼠 30 %TBSAⅢ度烫伤模型 ,分为正常对照组、烫伤组、去补体烫伤组 ,检测各组伤后 6h血清对体外培养的pMФs分泌超氧阴离子 (O2- )和一氧化氮 (NO)产量的影响 ,碘化丙锭 (PI)染色流式细胞术及凋亡电泳试验测定pMФs的凋亡情况。结果　与正常对照测值比较 ,烫伤血清诱导pMФs分泌较多的O2- 和NO ,去补体后烫伤血清诱导O2- 和NO的分泌量显著降低。烫伤血清诱导pMФs凋亡明显增加 ,去补体后烫伤血清和活性氧阻断剂PDTC及NO阻断剂AG能阻断绝大部分pMФs的凋亡。结论　重度烫伤小鼠血清补体能在体外诱导pMФs凋亡 ,O2- 和NO等炎性介质在其中发挥了重要作用     

Fibroblast transdifferentiation promotes conversion of M1 macrophages and replenishment of cardiac resident macrophages following cardiac injury in mice

Resident cardiac macrophages play important roles in homeostasis, maintenance of cardiac function, and tissue repair. After cardiac injury, monocytes infiltrate the tissue, undergo phenotypic and functional changes, and are involved in inflammatory injury and functional remodelling. However, the fate of cardiac infiltrating/polarized macrophages and the relationship between these cells and resident cardiac macrophage replenishment following injury remain unclear. Our results showed that angiotensin II induces cardiac fibroblast transdifferentiation into cardiac myofibroblasts (MFBs). In cocultures with MFBs and murine macrophages, the MFBs promoted macrophage polarization to M1 phenotype, followed by selective apoptosis, which was associated with TNF/TNFR1 axis and independent of NO production. Surprisingly, after 36 h of coculture, the surviving macrophages were converted to M2 phenotype and settled in heart, which was dependent on leptin produced by MFBs or polarized macrophages via the PI3K or Akt pathway. CCR2⁺CD45.2⁺ cells adoptively transferred into CD45.1⁺ mice with viral myocarditis, differentiated into CD45.2⁺CCR2⁺CX3CR1⁺ M2 cells during the resolution of inflammation and settled within the heart. Our data highlight a novel mechanism related to the renewal or replenishment of cardiac resident macrophages following cardiac injury; and suggest that transdifferentiation of cardiac fibroblasts may promote the resolution of inflammation.     

免疫抑制药对体外骨髓前体细胞向巨噬细胞分化的影响

目的 探讨细胞培养环境中添加免疫抑制药对骨髓前体细胞向巨噬细胞分化的影响. 方法 取C57BL/6小鼠颈椎脱臼致死,无菌操作制备骨髓前体细胞,在体外细胞培养体系中加入巨噬细胞集落刺激因子和三种免疫抑制药(雷帕菌素、环孢菌素A和紫杉醇),通过显微镜和流式细胞仪观察与检测诱导分化细胞的形态和细胞表面分子表达. 结果 骨髓前体细胞诱导分化的细胞具有典型巨噬细胞形态,细胞表面分子F4/80和CD11b表达都在95%以上,而CD11c表达极低,与对照组比较,诱导分化的巨噬细胞数明显减少,环孢菌素A对分化的巨噬细胞周期无影响,但紫杉醇明显增加诱导分化的巨噬细胞凋亡. 结论 3种免疫抑制药可能影响骨髓前体细胞向巨噬细胞分化.     

双歧杆菌的完整肽聚糖对LPS激活裸鼠腹腔巨噬细胞的影响

目的 了解被ＬＰＳ激活的裸鼠腹腔巨噬细胞在用双歧双歧杆菌的完整聚糖刺激后产生的ＮＯ、ｉＮＯＳ及ｃＧＭＰ的水平。方法 以Ｇｒｉｅｓｓ试剂、激光截聚焦显微镜以及入免法分别测定裸鼠腹腔巨噬细胞产生的ＮＯ、ｉＮＯＳ及ｃＧＭＰ的水平。结果 完整肽聚糖注射组裸鼠腹腔巨噬细胞在ＬＰＳ诱导下产生ＮＯ、ｉＮＯＳ及ｃＧＭＰ含量均显著高于对照组（Ｐ〈０．０１）。结论 双歧双歧杆菌的完整肽聚糖能协同ＬＰＳ激活巨噬细胞,使     

Enterobacterial tumor colonization in mice depends on bacterial metabolism and macrophages but is independent of chemotaxis and motility

Despite promising results and increasing attention in bacterial cancer therapy, surprisingly little is known about initial tumor colonization and the interaction between bacteria and surrounding tumor tissue. Here, we analyzed the role of chemotaxis, motility, and metabolism both in Escherichia coli and Salmonella enterica serovar Typhimurium strains upon intravenous injection into tumor-bearing mice. In contrast to previous models, we found that chemotaxis and motility do not play a significant role in tumor colonization and bacterial distribution within the tumor. Rather, the whole colonization and intratumoral migration process seems to be a passive mechanism that is influenced by the reticuloendothelial system of the host, by the tumor microenvironment and by the bacterial metabolism. These conclusions were supported by experimental data demonstrating that disruption of the basic branch of the aromatic amino acid biosynthetic pathway and depletion of macrophages, in contrast to flagellar mutations, led to significant changes in bacterial accumulation in tumors of live mice.