Adhesion and Function of Human Endothelial Cells Co-cultured on Smooth Muscle Cells

To evaluate interactions between human endothelial cells (ECs) and smooth muscle cells (SMCs) for the development of tissue-engineered vessels, we examined the adhesion and key cell properties of human ECs grown on quiescent human aortic SMCs. ECs attached to SMCs spread more slowly than ECs attached to fibronectin surfaces, and ECs aligned along the direction of the SMCs. ECs attached firmly and less than 5% of the cells were removed by shear stresses as high as 300 dyn cm⁻². Unlike porcine SMCs and co-cultures, human SMCs or co-cultures do not contract under flow, and the human ECs and SMCs in co-culture align toward the direction of flow. A confluent endothelium could be maintained in co-culture for over 30 days, and some of the ECs reoriented perpendicular to the SMCs after 9 days in static culture. Surface tissue factor levels in ECs and SMCs were less in co-culture than in monoculture. Co-culture induced an increase in calponin expression in SMCs. These findings show that human co-cultures can be maintained for long culture periods, where the endothelium remains confluent and responds to long-term exposure to flow, and EC–SMC interactions lead to an increase in SMC differentiation and an EC surface that is less thrombotic.     

A system for the direct co-culture of endothelium on smooth muscle cells

The development of a functional, adherent endothelium is one of the major factors limiting the successful development of tissue engineered vascular grafts (TEVGs). The adhesion and function of endothelial cells (ECs) on smooth muscle cells (SMCs) are poorly understood. The goal of this research was to optimize conditions for the direct culture of endothelium on SMCs, and to develop an initial assessment of co-culture on EC function. The co-culture consisted of a culture substrate, a basal adhesion protein, a layer of porcine SMCs, a medial adhesion protein, and a layer of porcine ECs. Conditions that led to successful co-culture were: a polystyrene culture substrate, a quiescent state for SMCs, subconfluent density for SMC seeding and confluent density for EC seeding, and fibronectin (FN) for the basal adhesion protein. EC adhesion was not enhanced by addition of FN, collagen I, collagen IV or laminin (LN) to the medial layer. 3-D image reconstruction by confocal microscopy indicated that SMCs did not migrate over ECs and the cells were present in two distinct layers. Co-cultures could be consistently maintained for as long as 10 days. After exposure to 5 dyne/cm(2) for 7.5 h, ECs remained adherent to SMCs. PECAM staining indicated junction formation between ECs, but at a lower level than that observed with EC monocultures. Co-culturing ECs with SMCs did not change the growth rate of ECs, but EC DiI-Ac-LDL uptake was increased. Thus, a confluent and adherent layer of endothelium can be directly cultured on quiescent SMCs.     

A Dynamically Cultured Collagen/Cells-Incorporated Elastic Scaffold for Small-Diameter Vascular Grafts

Abstract

There is an essential demand for tissue-engineered autologous small-diameter vascular grafts, which offer temporary supports and guides for vascular tissue organization, repair and remodeling. This study reports on the effect of collagen/smooth muscle cells (SMCs) mixtures under dynamic cultures and SMC-endothelial cell (ECs) co-culture on cell proliferation, uniform cell distribution, extracellular matrix deposition, and endothelial cells monolayer formation in tissue-engineered tubular arterial constructs of 4 mm inner diameter. Rabbit aortic SMCs were infiltrated with collagen solution in poly(L-lactide-co-?-caprolactone) (PLCL) scaffolds under vacuum to form collagenous gel and subjected to dynamic strain by culturing them in a dynamic perfusion bioreactor. The construct lumen was subsequently seeded with ECs and experiments were completed to create ECs–SMCs co-culture constructs. The collagen/SMCs incorporated elastic scaffold cultured under dynamic culture conditions promoted matrix deposition, leading to the development of tissue-engineered vascular constructs, and induced SMC to have more uniform cell distribution. Scanning electron microscopic examination and von Willebrand Factor staining demonstrated the presence of ECs spread over the lumen. Quantitative analysis of elastin contents demonstrated that the engineered vessels acquired similar elastin contents as native arteries. The collagen/SMCs/ECs incorporated PLCL scaffolds under dynamic culture conditions can be used as a scaffold for tissue engineering to facilitate small-diameter vascular-tissue formation.     

Development of an Endothelial–Smooth Muscle Cell Coculture Model Using Phenotype-Controlled Smooth Muscle Cells

A coculture of endothelial cells (ECs) and smooth muscle cells (SMCs), which mimics cellular interactions appearing in vivo, has been performed in studies on the relationship between atherogenesis and fluid shear stress conditions. Although healthy arteries in vivo consist of contractile phenotype SMCs, cultured cells used in many studies normally exhibit a synthetic phenotype. Here, we developed an EC–SMC coculture model to investigate the interactions between ECs and contractile SMCs, and examined the effect of shear stress applied to ECs on SMC phenotypes. Cultured human umbilical artery SMCs were differentiated into contractile states by arresting cell growth using a serum-free medium. Western blotting confirmed that SMC expression of contractile protein markers, α-smooth muscle actin (SMA) and calponin, increased to levels similar to those observed in arterial cells. After coculturing contractile SMCs with ECs separated by a collagen gel layer, the expression of α-SMA decreased under static conditions, indicating that the SMC phenotype tended to be synthetic by coculturing with ECs, but shear stress applied to cocultured ECs maintained the level of α-SMA expression in SMCs. The coculture model constructed in the present study will be a useful tool to investigate interactions between ECs and contractile SMCs under shear conditions.     

Connexin 30.2 is expressed in exocrine vascular endothelial and ductal epithelial cells throughout pancreatic postnatal development

Previously we have demonstrated that the GJ protein connexin 30.2 (Cx30.2) is expressed in pancreatic beta cells and endothelial cells (ECs) of the islet. In the present study, we address whether Cx30.2 is expressed in the exocrine pancreas, including its vascular system. For this, adult mouse pancreatic sections were double labeled with specific antibodies against Cx30.2 and CD31, an endothelial cell marker, or with anti-α-actin smooth muscle, a smooth muscle cell (SMC) marker or anti-mucin-1, a marker of epithelial ductal cells, using immunofluorescence (IF) studies. Cx30.2-IF hot spots were found at junctional membranes of exocrine ECs and SMCs of blood vessels. Furthermore, Cx30.2 was localized in mucin-1 positive cells or epithelial ductal cells. Using immunohistochemistry (IHC) studies, it was found that in vessels and ducts of different diameters, Cx30.2 was also expressed in these cell types. In addition, it was found that Cx30.2 is already expressed in these cell types in pancreatic sections of 3, 14 and 21 days postpartum. Moreover, this cell specific pattern of expression was also found in the adult rat, hamster and guinea pig pancreas. Expression of Cx30.2 mRNA and protein in the pancreas of all these species was confirmed by RT-PCR and Western blot studies. Overall, our results suggest that intercellular coupling mediated by Cx30.2 intercellular channels may synchronize the functional activity of ECs and SMCs of vascular cells, as well as of epithelial ductal cells after birth.     

Different sensitivity of human endothelial cells, smooth muscle cells and fibroblasts to topography in the nano–micro range

Cell adhesion, orientation and migration are influenced by surface topographies in the micrometer and nanometer range. In this work, we demonstrate the stimulation by topographical signals of human fibroblast cells (FCs), endothelial cells (ECs) and smooth muscle cells (SMCs). We systematically quantified the contact guidance alignment and directed migration of FCs, ECs and SMCs adhering to grooved substrates with lateral dimensions of 2–10 μm and depths of 50–200 nm. We found a common quantitative response characteristic of all three cell types: contact guidance significantly increased when the cells were cultured on substrates with smaller lateral dimensions or deeper grooves. Despite their general behavior, the three cell types exhibited a cell-type specific sensitivity to the groove patterns. The minimum groove depth to induce an orientation response and change cell shape was 50 nm for FCs and about two times deeper for ECs and SMCs. The degree of alignment and directed migration of the FCs along the grooves was significantly stronger than for the ECs and SMCs. We demonstrate that ECs and SMCs can be stimulated by topographical signals but are less sensitive than FCs.     

p38alpha MAP kinase-deficient mouse embryonic stem cells can differentiate to endothelial cells, smooth muscle cells, and neurons.

p38 MAP kinase alpha (p38alpha) regulates various cellular processes in adult cells, but little is known about its function in stem cells. We investigated the potential of wild type and p38alpha deficient mouse embryonic stem cells (ESCs) to differentiate into endothelial cells (ECs), smooth muscle cells (SMCs), and neurons. Our differentiation methods allowed simultaneous development of all these cell types. ECs formed monolayers similar to mature ECs and could assemble into vessel-like structures. SMCs had well-organized actin filaments with morphology similar to adult SMCs. Neurons exhibited well-developed cell bodies and elongated axons. Deletion of the p38alpha gene did not significantly compromise ESC differentiation since p38alpha-/- cells could express cell-specific markers and displayed similar overall morphology to the cells differentiated from p38alpha+/+ ESCs. Although p38alpha regulates various cellular activities of adult SMCs, ECs, and neurons, our data demonstrate that p38alpha is not essential for ESC differentiation to these cell types.     

Granuloma cells in chronic inflammation express CD205 (DEC205) antigen and harbor proliferating T lymphocytes: Similarity to antigen‐presenting cells

Granulomas are classified as immune or foreign body granulomas. Of these, the immune granulomas, a hallmark of granulomatous inflammation, are closely related to cell‐mediated immune responses. The aim of the present study is to characterize immune granuloma cells in 33 patients with granulomatous inflammation focusing on the expression of CD205 (DEC205), a cell surface marker of antigen presenting cells, and their spatial relationship to T cells. CD205 was frequently expressed by immune granuloma cells, in contrast to foreign body granuloma cells that lacked CD205 expression. T cells were not only distributed in a lymphocyte collar around the granuloma, but also present among the granuloma cells (termed ‘intra‐granuloma T cells’). Intra‐granuloma T cells stained positive for Ki‐67 (median positivity = 9.4%) by double immunostaining for CD3 and Ki‐67. This indicated the presence of proliferative stimuli within the granuloma that could activate the intra‐granuloma T cells. The labeling index of Ki‐67 in intra‐granuloma T cells was significantly higher than that of T cells in the lymphocyte collar (P < 0.0001) or T cells in the T cell zone (paracortex) of chronic tonsillitis or reactive lymphadenitis (P = 0.002). These data indicate a close similarity between immune granulomas and antigen presenting cells.     

供体年龄影响融合生长内皮祖细胞对平滑肌细胞表型转换及增殖迁移的作用

目的:探讨老龄和年轻个体来源融合生长状态内皮祖细胞(EPCs)对血管平滑肌细胞(SMCs)表型转换以及增殖和迁移的调节作用。方法:脱臼处死1~2月龄、19~26月龄SD大鼠,应用含15%FBS的DMEM/F12培养基(含内皮细胞生长添加剂100 mg/L、肝素100 mg/L、青霉素、链霉素各1×105U/L)培养EPCs,取1~2月龄大鼠腹主动脉,组织块法培养血管SMCs,应用Di I-Ac-LDL与FITC-UEA-1荧光双染以及α-SM-actin免疫荧光分别对EPCs和SMCs进行鉴定。建立细胞共培养体系,上室为融合生长状态的EPCs,下室为SMCs,实验分4组:(1)第3代SMCs(P3)组;(2)第4代SMCs(P4)组;(3)第4代SMCs与年轻大鼠来源EPCs共培养(P4YE)组;(4)第4代SMCs与老龄大鼠来源EPCs共培养(P4AE)组。Western blotting检测α-SM-actin和osteopontin蛋白的表达;[3H]-TdR掺入法检测SMCs增殖;细胞划痕实验检测SMCs的迁移能力。结果:与P3组相比,P4组的SMCsα-SM-actin表达显著下调,而osteopontin表达显著增强;P4YE组SMCs的α-SM-actin及osteopontin表达与P3组比较未见有显著差别;与P4组相比,年轻和老龄大鼠来源的EPCs均显著促进第4代SMCs的α-SM-actin和下调osteopontin的表达,抑制第4代SMCs的增殖和迁移;与老龄大鼠来源的EPCs相比,年轻大鼠来源的EPCs更能够显著延迟SMCs表型由收缩型向合成型转换,抑制SMCs增殖和迁移。结论:共培养融合生长状态的EPCs使血管SMCs表型转换延迟、抑制SMCs增殖和迁移,年轻大鼠来源的EPCs较老龄大鼠来源的EPC更显著延迟血管SMCs表型由收缩型向合成型转换,并具有更强的抑制血管SMCs增殖和迁移的能力。     

微元素粉末对大鼠血管内皮和平滑肌细胞膜电位的影响

目的:探讨微元素粉末(由铝、钛、硅等元素组成的超细粉末,粉末直径在0.5μm以下,microelementpowder,MP)对大鼠血管内皮和平滑肌膜电位的影响,探讨其改善微循环的机理。方法:培养大鼠肺血管内皮细胞和主动脉平滑肌细胞,用电位敏感的荧光探针和激光共聚焦显微镜测定细胞膜电位动态变化。结果:MP使平滑肌细胞显著超极化。ATP敏感钾通道(ATPsensitiveK⁺channel,K_ATP)阻滞剂优降糖(2μmol/L)对平滑肌膜电位无明显影响,但能完全逆转MP对平滑肌的超极化作用;MP使血管内皮细胞轻度超极化,其作用不受优降糖影响。结论:MP激活血管平滑肌K_ATP通道,使细胞膜超极化,从而扩张微血管和改善微循环。     

转染组织纤溶酶原激活物及内皮型一氧化氮合酶基因的内皮细胞和平滑肌细胞共同种植于人工血管对内膜增生的影响

背景：前期研究表明,双层细胞种植能有效提高内皮细胞保留率,将组织纤溶酶原激活物基因转染到内皮细胞中能提高其细胞溶解纤维蛋白的能力。 目的：采用双细胞种植及修饰内皮的组织纤溶酶原激活物基因提高内皮细胞保留率和抗栓能力,通过内皮型一氧化氮合酶基因调控平滑肌细胞的增殖,观察对小口径人工血管通畅率的影响。 方法：以4种不同组合细胞(内皮细胞+平滑肌细胞SMC,内皮细胞/组织纤溶酶原激活物+平滑肌细胞,内皮细胞+平滑肌细胞/内皮型一氧化氮合酶,内皮细胞/组织纤溶酶原激活物+平滑肌细胞/内皮型一氧化氮合酶)种植在PTFE管腔面。将新西兰大白兔随机分成4组,4种人工血管经旁路分别移植在4组兔的腹主动脉上。 结果与结论：移植后60 d,种植内皮细胞+平滑肌细胞组和内皮细胞+平滑肌细胞/内皮型一氧化氮合酶组内膜厚度无明显差异(P > 0.05)。与内皮细胞/组织纤溶酶原激活物+平滑肌细胞/内皮型一氧化氮合酶组相比,未转染内皮型一氧化氮合酶组(内皮细胞/组织纤溶酶原激活物+平滑肌细胞）内膜明显增厚(P < 0.05);未转染组织纤溶酶原激活物组(内皮细胞+平滑肌细胞/内皮型一氧化氮合酶)内膜较薄(P < 0.05)。提示组织纤溶酶原激活物基因转染可以促进血管内膜增生导致血管狭窄,但同时转入内皮型一氧化氮合酶基因可以抑制组织纤溶酶原激活物的促进平滑肌细胞增殖及内膜增生的作用。     

剪切力条件下血管内皮细胞与平滑肌细胞的相互作用

血管内皮细胞(endothelial cells,ECs)与平滑肌细胞(smooth muscle cells,SMCs)是血管壁的主要细胞,它们之间的相互作用在维持血管正常的生理功能以及心血管疾病的发生发展过程中至关重要。为真实模拟ECs与SMCs体内条件下的位置关系与生长状态,人们建立了多种共培养系统。介绍当前几种常用的能够加载流动剪切力的共培养系统,并分别比较其优势与不足;简要总结剪切力条件下ECs与SMCs相互作用对ECs与SMCs表型与分布、SMCs生长与迁移、ECs表面相关黏附分子表达的影响。研究表明,一氧化氮(NO)、细胞因子、microRNA等可以作为信号分子介导ECs与SMCs之间的相互作用。     

Expression of matrix Gla protein and osteonectin mRNA by human aortic smooth muscle cells.

BACKGROUND: Recent data indicate that matrix proteins such as matrix Gla protein (MGP) and osteonectin (ON) influence not only mineralization of vasculature but smooth muscle cell (SMC) differentiation. METHODS: We examined whether MGP and ON are expressed by human aortic SMCs in vivo using Northern blotting, in situ hybridization and immunohistochemistry. RESULTS: MGP and ON mRNAs were strongly expressed in the aorta without atherosclerosis from newborn and four young subjects up to 10 years old. In the aorta from 15 adult cases, MGP and ON mRNAs were decreased as atherosclerosis developed. We determined cell type and distribution of the MGP- and ON mRNA-expressing cells by in situ hybridization and immunohistochemistry. In the aorta obtained from newborn and young subjects, SMCs in the media and thin intima expressed MGP mRNA and, to a lesser extent, ON mRNA. In the adult aorta with fibrous thickening, MGP mRNA was expressed by intimal SMCs and subpopulation of medial SMCs. Osteonectin mRNA was expressed mainly by intimal SMCs and few medial SMCs. Double immunohistochemical staining revealed that both MGP- and ON protein-expressing cells were positive for anti-alpha-smooth muscle actin antibody, aortic SMCs. CONCLUSIONS: These results suggested that MGP and ON expression by aortic SMCs might be regulated by the degree of atherosclerosis and SMC differentiation in human aorta.     

Effect of Fluid Shear Stress on Migration of Vascular Smooth Muscle Cells in Cocultured Model

Migration of smooth muscle cells (SMCs) in hyperplasia is thought to have a correlation with blood flow conditions. In this study, the effect of shear stress applied to endothelial cells (ECs) on SMC migration was examined using a newly designed EC–SMC coculture model (CM), in which bovine SMCs and ECs were separated by a collagen layer and a membrane filter. After exposing the CM to shear stresses of 0.5, 1.0, or 1.5 Pa for 48 h, the number of SMCs migrating into the collagen layer was counted. Under static conditions, the migration of SMCs in the CM increased compared with SMCs cultured alone. Shear stress of 1.5 Pa significantly suppressed the SMC migration (p < 0.05) compared with the static CM. Media conditioned with the CM exposed to shear stress of 1.0 Pa (p < 0.05) and 1.5 Pa (p < 0.005) exhibited reduction in activated matrix metalloproteinase-2 (MMP-2) compared with the static CM, as analyzed by zymography. Addition of an inhibitor of nitric oxide (NO) synthase, N ^ω-nitro-l-arginine methyle ester, to the media inhibited the effect of 1.5 Pa shear stress on SMC migration but MMP-2 activity was unaffected. These results suggest that physiological shear stress has protective roles in atherosclerogenesis.     

In vitro model of atherosclerosis using coculture of arterial wall cells and macrophage

In order to determine the precise mechanism of the interactions between different types of cells, which are common phenomena in tissues and organs, the importance of coculture techniques are becoming increasingly important. In the area of cardiology, artificial arteries have been developed, based on the understanding of physiological communication of the arterial smooth muscle cells (SMC), endothelial cells (EC), and the extracellular matrix (ECM). In the study of atherosclerosis, the modification of low-density lipoprotein (LDL), which result in the recruitment and accumulation of white blood cells, especially, monocytes/macrophages, and foam cell formation, are hypothesized. Although there are well known animal models, an in vitro model of atherogenesis with a precisely known atherogenesis mechanism has not yet been developed. In this paper, an arterial wall reconstruction model using rabbit primary cultivated aortic SMCs and ECs, was shown. In addition, human peripheral monocytes were used and the transmigration of monocytes was observed by scanning electron and laser confocal microscopy. Monocyte differentiation into macrophages was shown by immunohistochemistry and comprehensive gene expression analysis. With the modified form of LDL, the macrophages were observed to accumulate lipids with a foamy appearance and differentiate into the foam cells in the ECM between the ECs and SMCs in the area of our coculture model.     

Fluid flow mechanotransduction in vascular smooth muscle cells and fibroblasts

Understanding how vascular wall endothelial cells (ECs), smooth muscle cells (SMCs), and fibroblasts (FBs) sense and transduce the stimuli of hemodynamic forces (shear stress, cyclic strain, and hydrostatic pressure) into intracellular biochemical signals is critical to prevent vascular disease development and progression. ECs lining the vessel lumen directly sense alterations in blood flow shear stress and then communicate with medial SMCs and adventitial FBs to regulate vessel function and disease. Shear stress mechanotransduction in ECs has been extensively studied and reviewed. In the case of endothelial damage, blood flow shear stress may directly act on the superficial layer of SMCs and transmural interstitial flow may be elevated on medial SMCs and adventitial FBs. Therefore, it is also important to investigate direct shear effects on vascular SMCs as well as FBs. The work published in the last two decades has shown that shear stress and interstitial flow have significant influences on vascular SMCs and FBs. This review summarizes work that considered direct shear effects on SMCs and FBs and provides the first comprehensive overview of the underlying mechanisms that modulate SMC secretion, alignment, contraction, proliferation, apoptosis, differentiation, and migration in response to 2-dimensional (2D) laminar, pulsatile, and oscillating flow shear stresses and 3D interstitial flow. A mechanistic model of flow sensing by SMCs is also provided to elucidate possible mechanotransduction pathways through surface glycocalyx, integrins, membrane receptors, ion channels, and primary cilia. Understanding flow-mediated mechanotransduction in SMCs and FBs and the interplay with ECs should be helpful in exploring strategies to prevent flow-initiated atherosclerosis and neointima formation and has implications in vascular tissue engineering.     

Regulation and function of an activation-dependent epitope of the beta 1 integrins in vascular cells after balloon injury in baboon arteries and in vitro.

Migration and proliferation of endothelial cells (ECs) and smooth muscle cells (SMCs) contribute to the response to injury in damaged and atherosclerotic vessels. These events might be regulated by cellular interactions with extracellular matrix through the expression and activation of integrins. To study the functions of beta 1 integrins in the vessel wall, we used monoclonal antibody (MAb) 15/7, which recognizes an activation epitope of beta 1 integrin subunits, and MAb 8A2, which induces a high affinity form of beta 1 integrins recognized by MAb 15/7. Immunohistochemical analyses were done on samples of normal baboon saphenous arteries and from arteries subjected to balloon injury. EC and SMC expressed the activation epitope of beta 1 integrin in uninjured arteries. By contrast, in balloon-injured arteries 6 weeks after injury, regenerating EC did not express the activation epitope, and there was no decrease in the expression of total beta 1 integrin, whereas SMC migrating into the intima exhibited decreased expression of the total and activated beta 1 integrin. Flow cytometer analysis of cultured cells indicated that baboon EC and SMC weakly express the activation epitope of beta 1 integrin. Next, we determined by utilizing MAb 8A2 the effects of increased expression of activation epitope of beta 1 integrin on the functions of SMC and EC. The activation of beta 1 integrins on SMC induced by MAb 8A2 enhanced SMC adhesion and suppressed SMC migration in a Boyden chamber assay. SMC proliferation was inhibited by MAb 8A2 dose-dependently. Similarly, MAb 8A2-induced activation of beta 1 integrins on EC suppressed EC migration into a wound. However, MAb 8A2 did not affect the basic fibroblast growth factor-induced proliferation of EC, although it blocked the decrease in EC number caused by the removal of basic fibroblast growth factor. These results suggest that activation of beta 1 integrins in vascular cells is regulated in a cell-type dependent manner and plays an important role in modulating vascular cell functions.     

Significance of cell proliferation markers (Minichromosome maintenance protein 7, topoisomerase IIα and Ki‐67) in cavital fluid cytology: Can we differentiate reactive mesothelial cells from malignant cells?

The aim of this study was to evaluate whether immunocytochemical expressions of proliferation markers, such as minichromosome maintenance protein 7 (MCM 7), topoisomerase IIα (topo IIα), and Ki‐67, in reactive mesothelial cells and malignant cells obtained from cavital fluids could be useful for their differential diagnosis. Samples diagnosed as reactive mesothelial cells (14 cases) or malignant tumors (28 cases) in cavital fluids were examined. Immunocytochemical staining of MCM 7, topo IIα, and Ki‐67 was performed with the universal immunoperoxidase polymer method. In reactive mesothelial cells, MCM 7 was stained in a fine granular pattern and its distribution was uniform in the nuclei. Topo IIα and Ki‐67 were stained in a coarse granular pattern and the distributions were the same as MCM 7. In contrast, in malignant cells, MCM 7 was stained in an irregular and fine granular pattern, and topo IIα and Ki‐67 were stained in a uniform and coarse granular pattern. Labeling indices of MCM 7 (cut‐off value; 30%, sensitivity; 100%, and specificity; 100%), topo IIα (cut‐off value; 15%, sensitivity; 89.3%, and specificity; 92.9%) and Ki‐67 (cut‐off value; 30%, sensitivity; 64.3%, and specificity; 92.9%) of malignant cells were significantly higher than those of reactive mesothelial cells. MCM 7, topo IIα, and Ki‐67 are different types of cell proliferation markers. MCM 7 and topo IIα, in particular, could be reliable tools for differential diagnosis between reactive mesothelial cells and malignant cells. Diagn. Cytopathol. 2010. © 2009 Wiley‐Liss, Inc.     

Distribution of aldehyde dehydrogenase 1-positive stem cells in benign mammary tissue from women with and without breast cancer

Isfoss B L, Holmqvist B, Alm P & Olsson H
(2012) Histopathology  60, 617–633
Distribution of aldehyde dehydrogenase 1‐positive stem cells in benign mammary tissue from women with and without breast cancer Aims: Aldehyde dehydrogenase 1 (ALDH1) in female breast tissue has been linked to stem cells, but little is known about the benign cellular organization in situ. We investigated the distribution of ALDH1‐immunoreactive (ALDH1+) cells in histomorphologically benign breast tissue from 28 women with or without breast cancer. Methods and results: ALDH1+ cells were detected in benign tissue of women aged 20–72 years, located most commonly at the luminal and intermediate ductular levels and in the stroma. ALDH1+ cell populations and Ki67+ cell populations were present in separate ductules, both cell types rarely showing epithelial differentiation. ALDH1+ cells were non‐reactive to Ki67 and oestrogen receptor. Stromal round/oval ALDH1+ non‐leukocyte cells in both age groups expressed contractile protein. There was a lower concentration of luminal and intermediate ductular ALDH1+ cells in postmenopausal women than in premenopausal women, and in cancer patients than in non‐cancer patients, and a higher concentration in women receiving exogenous hormones. Conclusions: This study provides further evidence for the stem cell character of ALDH1+ cells, here in benign breast tissue of cancer and non‐cancer patients throughout non‐lactating adult life, and contributes evidence of benign stromal ALDH1+ cells. The distribution of ductular ALDH1+ stem cells appears to be influenced by hormonal status.     

Resident cell lineages are preserved in pulmonary vascular remodeling

Pulmonary vascular remodeling is the main pathological hallmark of pulmonary hypertension disease. We undertook a comprehensive and multilevel approach to investigate the origin of smooth muscle actin‐expressing cells in remodeled vessels. Transgenic mice that allow for specific, inducible, and permanent labeling of endothelial (Cdh5‐tdTomato), smooth muscle (Acta2‐, Myh11‐tdTomato), pericyte (Cspg4‐tdTomato), and fibroblast (Pdgfra‐tdTomato) lineages were used to delineate the cellular origins of pulmonary vascular remodeling. Mapping the fate of major lung resident cell types revealed smooth muscle cells (SMCs) as the predominant source of cells that populate remodeled pulmonary vessels in chronic hypoxia and allergen‐induced murine models. Combining in vivo cell type‐specific, time‐controlled labeling of proliferating cells with a pulmonary artery phenotypic explant assay, we identified proliferation of SMCs as an underlying remodeling pathomechanism. Multicolor immunofluorescence analysis showed a preserved pattern of cell type marker localization in murine and human pulmonary arteries, in both donors and idiopathic pulmonary arterial hypertension (IPAH) patients. Whilst neural glial antigen 2 (chondroitin sulfate proteoglycan 4) labeled mostly vascular supportive cells with partial overlap with SMC markers, PDGFRα‐expressing cells were observed in the perivascular compartment. The luminal vessel side was lined by a single cell layer expressing endothelial markers followed by an adjacent and distinct layer defined by SMC marker expression and pronounced thickening in remodeled vessels. Quantitative flow cytometric analysis of single cell digests of diverse pulmonary artery layers showed the preserved separation into two discrete cell populations expressing either endothelial cell (EC) or SMC markers in human remodeled vessels. Additionally, we found no evidence of overlap between EC and SMC ultrastructural characteristics using electron microscopy in either donor or IPAH arteries. Lineage‐specific marker expression profiles are retained during pulmonary vascular remodeling without any indication of cell type conversion. The expansion of resident SMCs is the major underlying and evolutionarily conserved paradigm of pulmonary vascular disease pathogenesis. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.