Mechanical and Cellular Changes During Compaction of a Collagen-Sponge-Based Corneal Stromal Equivalent

The need for corneas suitable for transplantation, combined with the decreasing supply, has fueled interest in the development of a corneal replacement. In this study, a collagen-sponge-based stromal equivalent, consisting of human corneal fibroblasts cultured on a type I collagen sponge, was maintained in culture for up to 21 days and characterized with respect to mechanical properties and cellular behavior. The Young's modulus of the stromal equivalent varied from 95 to 370 Pa, and its permeability varied from 5.3 x 10(-8) - 4.2 x 10(-7) m4 N(-1) s(-1). The greatest changes occurred during the first few days in culture, but the mechanical properties continued to change during the entire 21 days. Cell traction stress, determined from sponge compaction and DNA count, decreased during the compaction process with the maximum traction value the initial value of 6.6 +/- 2.9 x 10(-3) Pacm3 cell(-1). Microarray data showed that the expression level of fibronectin, decorin sulfate, collagenase, and gelatinase A was upregulated at day 14 in the sponge. This suggested that the repair fibroblast phenotype was being expressed by the fibroblasts. Additional analysis suggested that a subpopulation of cells expressed the myofibroblast phenotype.     

Immunohistochemical and electron microscopic observations of stromal cells in the human oviduct mucosa

Stromal cells in the lamina propria of the human oviduct mucosa are unique cells that can differentiate into decidual cells during ectopic pregnancy in the oviduct. The nature of stromal cells is still unknown. In the present study, we investigated human oviductal stromal cells with transmission electron microscopy and immunohistochemistry and revealed that they had ultrastructural features similar to myofibroblasts and expressed alpha-smooth muscle actin, a marker used to identify myofibroblasts. Primary cilia were also one of the characteristic profiles of the stromal cells. These findings showed that the connective tissue-stromal cells in the human oviduct mucosa are myofibroblasts. They are considered to play an important role in the transport of oocytes by bringing about contraction of the mucosal folds.     

Inhibition of activin receptor-like kinase 5 attenuates bleomycin-induced pulmonary fibrosis

Activin receptor-like kinase 5 (ALK5) is a type I receptor of transforming growth factor (TGF)-beta. ALK5 inhibition has been reported to attenuate the tissue fibrosis including pulmonary fibrosis, renal fibrosis and liver fibrosis. To elucidate the inhibitory mechanism of ALK5 inhibitor on pulmonary fibrosis in vivo, we performed the histopathological assessment, gene expression analysis of extracellular matrix (ECM) genes and immunohistochemistry including receptor-activated Smads (R-Smads; Smad2/3), CTGF, myofibroblast marker (alpha-smooth muscle actin; aSMA) and type I collagen deposition in the lung using Bleomycin (BLM)-induced pulmonary fibrosis model. ALK5 inhibitor, SB-525334 (10 mg/kg or 30 mg/kg) was orally administered at twice a day. Lungs were isolated 5, 7, 9 and 14 days after BLM treatment. BLM treatment led to significant pulmonary fibrotic changes accompanied by significant upregulation of ECM mRNA expressions, Smad2/3 nuclear translocation, CTGF expression, myofibroblast proliferation and type I collagen deposition. SB-525334 treatment attenuated the histopathological alterations in the lung, and significantly decreased the type I and III procollagen and fibronectin mRNA expression. Immunohistochemistry revealed that SB-525334 treatment showed significant attenuation in Smad2/3 nuclear translocation, decrease in CTGF-expressing cells, myofibroblast proliferation and type I collagen deposition. These results suggest that ALK5 inhibition attenuates R-Smads activation thereby attenuates pulmonary fibrosis.     

Cellular diversity of human placental stem villi: an ultrastructural and immunohistochemical study

The aim of the study was to investigate the distribution and differentiation of cell types in the stroma of human placental stem villi (SV). A total of 14 human term placental tissues were studied. Double immunolabeling was performed for desmin-vimentin, desmin--smooth actin and vimentin--smooth actin. Cytokeratin 7, proliferating cell nuclear antigen immunolabeling was also performed. Parallel tissue samples were examined by transmission electron microscopy. HSCORE was performed for the semi-quantitative analysis of distribution of cells in the stroma of SV. Vimentin-labeled cells were mostly distributed in the subtrophoblastic area. Desmin-vimentin double immunolabeling was mainly localized in the triangular area and to a lesser degree in the perivascular area and vessel walls (p=<0.001). However, desmin- smooth actin labeling was observed predominantly in the vessel wall and perivascular area. Vimentin- smooth actin immunoreactivity was significantly stronger in the triangular and perivascular areas compared to the vessel walls (p=0.003).

Ultrastructurally, cells in the stroma of SV were mesenchyme cells, reticulum cells, fibroblasts, myofibroblasts, smooth muscle cells, and Hofbauer cells, filamented and vacuolated cells. The differentiation of myofibroblasts in the triangular and perivascular areas may play a role in maturation of SV and villous contractility, modulation of the intervillous space and this may have effects on maternofetal placental circulation.     

Retroprosthetic membrane: A complication of keratoprosthesis with broad consequences

Keratoprosthesis (KPro) devices have the remarkable ability to restore vision in patients suffering from corneal blindness who are poor candidates for traditional penetrating keratoplasty. However, eyes with KPro can experience various complications, including the development of retroprosthetic membrane (RPM). RPMs reduce visual acuity in patients due to physical obstruction of the visual axis, but studies have shown that RPM can also lead to a variety of other consequences, from melting of the corneal carrier graft to precipitating retinal detachments. Histopathologic studies have shown that RPMs are composed of elements from both the recipient and donor. The presence of myofibroblasts in RPMs imparts them with contractile properties, which can contribute to their downstream complications, including angle closure, hypotony, and retinal detachment. At present, there are limited treatments to combat the growth of RPM. Future therapies could include anti-metabolites and targeted anti-inflammatory treatments, as well as device coatings or textured device surfaces that can hinder RPM proliferation. The long-term success of KPro depends on devising an effective solution for preventing RPM growth.     

Acute and chronic effect of alcohol on Ca2+ channels in hepatic stellate cells

BACKGROUND: Hepatic stellate cells have been reported to play important roles in the regulation of hepatic microcirculation via cell contraction. Increase in intracellular calcium concentration is required to induce cell contraction. We have already reported the existence of L-type voltage-operated Ca2+ channels (VOCC), such as smooth muscle cells. On the other hand, alcohol has been known to disturb hepatic microcirculation. In this study, we evaluated the effect of acute and chronic treatment of alcohol on VOCC in rat hepatic stellate cells. METHODS: Stellate cells isolated from rats were cultured with or without 100 mM ethanol for up to 14 days. VOCC were detected by the patch clamp technique. Cells cultured for 14 days without ethanol were exposed to ethanol to investigate calcium current during membrane depolarization. alpha-Smooth muscle actin (alpha-SMA) was stained by indirect immunofluorescence. RESULTS: In the control model, VOCC were recognized in cells cultured for more than 7 days. Detection of VOCC increased from 9% on day 7 to 55% on day 14. On the other hand, VOCC in cells treated chronically with 100 mM ethanol appeared earlier than in the control and the incidences were significantly higher than those of the control accompanied with an early activation of cells. In contrast, simultaneous exposure to ethanol during the membrane depolarization inhibited Ca2+ current. CONCLUSIONS: The expression of Ca2+ channels in stellate cells were up-regulated by the chronic treatment of alcohol accompanied with the transformation to myofibroblast-like phenotype. However, alcohol itself inhibited Ca2+ current.     

肌成纤维细胞与肾小球硬化

肌成纤维细胞是一种超微结构介于平滑肌细胞和成纤维细胞之间的细胞,具有很强的分泌细胞外基质及收缩的功能,在组织创伤愈合、纤维化形成等方面发挥重要的作用。本文就肌成纤维细胞的特征,及其在肾小球硬化形成发展中的作用和意义等方面进行综述。     

Untersuchungen zum Mucopolysaccharid (Glucosaminoglykan)-Stoffwechsel des juvenilen Nasenrachenfibroms

Zusammenfassung Es wird über Untersuchungen zum Mucopolysaccharid (Glucosaminoglykan)-Stoffwechsel des juvenilen Nasenrachenfibroms (j. NF.) anhand 10 bausteinhistochemisch und 4 ultrahistochemisch untersuchter Gewächse berichtet.Die Ergebnisse gestatten eine eingehende Charakterisierung der reaktiven Polysaccharidkomponenten und die topologische Zuordnung auf geweblicher und zellulärer Ebene.Dabei wird die intrazelluläre Synthese perjodreaktiven Materials und dessen nachfolgende Ausschleusung in klassischen und histiozytenähnlich strukturierten Fibroblasten nachgewiesen. Negative Ladungen sind nach unseren ultrahistochemischen Untersuchungen vorzugsweise der dem äußeren Plasmalemm aufliegenden Polysaccharidhülle (Glykokalyx, cell coat) zuzuordnen, die an den Zellen des j. NF. eine regelmäßige Ausbildung zeigt. Mit zunehmender Grundsubstanzbildung treten saure Gruppen verstärkt in Erscheinung, die als Carboxyl- und Sulfatgruppen einzuschätzen sind. Neben Hyaluronsäure ist Chondroitinsulfat (Chondroitinsulfat-4 und Chondroitinsulfat-6) als Hauptvertreter bindegewebiger Mucosubstanz anzutreffen, deren ultrahistochemische Erscheinungsform Chondroitin-Proteoglykanen entspricht, wie sie in ausdifferenzierten kollagenen Geweben vorkommen.Nach unseren Ergebnissen entsprechen sekretorische Leistung der Fibroblasten und Verhalten der Grundsubstanz oder denen ausdifferenzierter mesenchymaler Gewebe. Durch die Ergebnisse wird die Hypothese von einem organoiden Wachstum der j. NF. und ihre Einordnung unter die organoiden mesenchymalen Proliferationsprozesse gestützt.Eine eingehende Charakterisierung der reaktiven Gruppen der Grundsubstanz ist im Hinblick auf den Differenzierungsgrad mesenchymaler Proliferationsprozesse, insbesondere Tumoren wichtig (Kindblom u. Angervall, 1975), da die Synthese der Glucosaminoglykan-Proteinkomplexe (MPS-Proteinkomplexe) für die Ausbildung der jeweils typischen histologischen Muster mesenchymaler Gewebe eine entscheidende Rolle spielt (Meyer et al., 1956; Spicer et al., 1965; Mathews, 1967; Übersicht bei Muir, 1969).In Untersuchungen zur Zytologie und Zytogenese des juvenilen Nasenrachenfibroms (j. NF) hatten neben der angioplastischen Komponente, die durch ihre Organellenkompositionen charakterisierten Fibroblastenmodulationen im Mittelpunkt des Interesses gestanden (Stiller et al., 1976; Küttner et al., 1976).Ziel der vorliegenden Arbeit ist, die Leistungen dieser Fibroblasten im Mucopolysaccharidstoffwechsel (= Glucosaminoglykane) mittels histochemischer Methoden, teilweise in Kombination mit elektronenmikroskopischer Technik darzustellen.     

肌成纤维细胞在创面收缩中的作用

目的：研究肌成纤维细胞在创面收缩过程中的作用，探讨创面收缩机理。方法：对兔耳及背部创面进行创面收缩观察并用电镜、免疫组化等方法对比研究肌成纤维细胞出现及变化规律。结果：肌成纤维细胞出现的时间晚于创面收缩时间，出现的量与创面收缩的程度关系密切。结论；肌成纤维细胞不是创面收缩的始动因素，但参与了创面收缩过程。     

平滑肌肌动蛋白(SMA)在胆道愈合过程中的表达及意义

目的：观察ＳＭＡ及肌成纤维细胞在胆道愈合过程中的表达，探讨其在医源性胆管狭窄形成过程中的作用及意义。方法通过制作犬肝外胆管损伤修复模型，分别于术后１周、３周、３月、６月取材行ＳＭＡ免疫组化ＳＰ染色观察。结果ＳＭＡ表达于肌成纤维细胞浆，术后１周至６月表达均较强。肌成纤维细胞功能活跃，细胞外基质过度沉积，结果导致瘢痕性挛缩，管腔狭窄，结论ＳＭＡ及肌成纤维细胞是导致胆道瘢痕性挛缩的主要原因。