AB745 Sigma-AldrichAnti-Collagen Type I Antibody

Prior studies have demonstrated that smooth muscle cell (SMC) proliferation, migration, and extracellular matrix production increase with hydrostatic pressure in vitro. We have engineered highly compliant small-diameter arterial constructs by culturing primary adult baboon arterial SMCs under pulsatile perfusion on tubular, porous, elastomeric scaffolds composed of poly(glycerol sebacate) (PGS). This study investigates the effect of hydrostatic pressure on the biological and mechanical properties of PGS-based engineered arterial constructs. Pressure was raised using a downstream needle valve during perfusion while preserving flow rate and pulsatility, and constructs were evaluated by pressure-diameter testing and biochemical assays for collagen and elastin. Pressurized constructs contained half as much insoluble elastin as baboon common carotid arteries but were significantly less compliant, while constructs cultured at low hydrostatic pressure contained one-third as much insoluble elastin as baboon carotids and were similar in compliance. Hydrostatic pressure significantly increased construct burst pressure, collagen and insoluble elastin content, and soluble elastin concentration in culture medium. All arteries and constructs exhibited elastic recovery during pressure cycling. Hydrostatic pressure did not appear to affect radial distribution of SMCs, collagens I and III, and elastin. These results provide insights into the control of engineered smooth muscle tissue properties using hydrostatic pressure.Copyright © 2011 Wiley Periodicals, Inc.

Two series of 3D scaffolds based on ε-caprolactone were synthesized. The pore size and architecture (spherical interconnected pores) was the same in all the scaffolds. In one of the series of scaffolds, made of pure ε-polycaprolactone, the volume fraction of pores varied between 60% and 85% with the main consequence of varying the interconnectivity between pores since the pore size was kept constant. The other scaffolds were prepared with copolymers made of a ε-caprolactone-based hydrophobous monomer and hydroxyethyl acrylate, as the hydrophilic component. Thus, the hydrophilicity and, presumably, the adhesion properties varied monotonously in the copolymer series while porosity was kept constant. A suspension of human chondrocytes in culture medium was injected in the 3D scaffolds and cultured in static conditions up to 28 days. SEM and immunofluorescence assays allowed characterizing cells and extracellular matrix inside the scaffolds after different culture times. To do that, cross sections of the scaffolds were observed by SEM and confocal microscopy. The quantity of cells inside the scaffolds decreases with a decrease of the volume fraction of pores, due to the lack of interconnectivity between the cavities. The scaffolds up to a 30% of hydrophilicity behave in a similar way than the hydrophobous; a further increase of the hydrophilicity rapidly decreases cell viability. In all the experiments production of collagen type I, type II, and aggrecan was found, and some cells were Ki-67 positive, showing that some cells are adhered to the pore walls and maintain their dedifferentiated phenotype even when cultured in three-dimensional conditions.

To explore whether Radix Dipsaci (RD) exhibits beneficial effects on tendon healing.

Leptospirosis is a global public health problem, primarily in the tropical developing world. The pathogenic mechanisms of the causative agents, several members of the genus Leptospira, have been underinvestigated. The exception to this trend has been the demonstration of the binding of pathogenic leptospires to the extracellular matrix (ECM) and its components. In this work, interactions of Leptospira interrogans bacteria with mammalian cells, rather than the ECM, were examined. The bacteria bound more efficiently to the cells than to the ECM, and a portion of this cell-binding activity was attributable to attachment to glycosaminoglycan (GAG) chains of proteoglycans (PGs). Chondroitin sulfate B PGs appeared to be the primary targets of L. interrogans attachment, while heparan sulfate PGs were much less important. Inhibition of GAG/PG-mediated attachment resulted in partial inhibition of bacterial attachment, suggesting that additional receptors for L. interrogans await identification. GAG binding may participate in the pathogenesis of leptospirosis within the host animal. In addition, because GAGs are expressed on the luminal aspects of epithelial cells in the proximal tubules of the kidneys, this activity may play a role in targeting the bacteria to this critical site. Because GAGs are shed in the urine, GAG binding may also be important for transmission to new hosts through the environment.

Our objective was to examine the potential of a genipin cross-linked human fibrin hydrogel system as a scaffold for articular cartilage tissue engineering. Human articular chondrocytes were incorporated into modified human fibrin gels and evaluated for mechanical properties, cell viability, gene expression, extracellular matrix production and subcutaneous biodegradation. Genipin, a naturally occurring compound used in the treatment of inflammation, was used as a cross-linker. Genipin cross-linking did not significantly affect cell viability, but significantly increased the dynamic compression and shear moduli of the hydrogel. The ratio of the change in collagen II versus collagen I expression increased more than 8-fold over 5 weeks as detected with real-time RT-PCR. Accumulation of collagen II and aggrecan in hydrogel extracellular matrix was observed after 5 weeks in cell culture. Overall, our results indicate that genipin appeared to inhibit the inflammatory reaction observed 3 weeks after subcutaneous implantation of the fibrin into rats. Therefore, genipin cross-linked fibrin hydrogels can be used as cell-compatible tissue engineering scaffolds for articular cartilage regeneration, for utility in autologous treatments that eliminate the risk of tissue rejection and viral infection.

The construction of stable engineered tissue depends on the formation of a functional connective tissue produced by cells locally. A major component of connective tissue is collagen. Its deposition into a stable matrix depends on the enzymatic extracellular conversion of procollagen to collagen. This step is very slow in vitro and we hypothesized that this is due to a lack of crowdedness and insufficient excluded volume effect (EVE) in culture media. We used neutral (670 kDa) and negatively charged dextran sulfate (DxS, 500 kDa) to create EVE in cell cultures and to enhance in vitro matrix formation by accelerating procollagen conversion. Biochemical analyses in 2 human fibroblast lines revealed mostly unprocessed procollagen in uncrowded culture medium, whereas in the presence of DxS, procollagen conversion occurred and most of the collagen was associated with the cell layer. Immunocytochemistry confirmed DxS-related collagen deposition that colocalized with fibronectin. The large neutral dextran showed, in identical concentration ranges, no effects that correlated well with its smaller hydrodynamic radius as determined by dynamic light scattering. This predicted a 10 times bigger crowding power of DxS and benchmarks it as a potentially promising crowding agent facilitating the formation of extracellular matrix in vitro.

Connective tissue growth factor (CTGF) has recently been recognized as an important profibrotic factor and is up-regulated in various renal diseases with fibrosis. The present study describes the sequential localization of CTGF mRNA and its association with transforming growth factor (TGF)-beta1 in human crescentic glomerulonephritis (CRGN). Furthermore, we examined the phenotype of CTGF-expressing cells using serial section analysis. Kidney biopsy specimens from 18 CRGN patients were examined using in situ hybridization and immunohistochemistry. CTGF mRNA was expressed in the podocytes and parietal epithelial cells (PECs) in unaffected glomeruli. In addition, it was strongly expressed in the cellular and fibrocellular crescents, particularly in pseudotubule structures. Serial sections revealed that the majority of CTGF mRNA-positive cells in the crescents co-expressed the epithelial marker cytokeratin, but not a marker for macrophages. Moreover, TGF-beta1, its receptor TGF-beta receptor-I, and extracellular matrix molecules (collagen type I and fibronectin) were co-localized with CTGF mRNA-positive crescents. Our results suggest that CTGF is involved in extracellular matrix production in PECs and that it is one of the mediators promoting the scarring process in glomerular crescents.

Charcot-Marie-Tooth type 1 disease (CMT1) is a group of inherited demyelinating neuropathies caused by mutations in genes expressed by myelinating Schwann cells. Rather than demyelination per se, alterations of Schwann cell-axon interactions have been suggested as the main cause of motor-sensory impairment in CMT1 patients. In an attempt to identify molecules that may be involved in such altered interactions, the extracellular matrix (ECM) remodeling occurring in CMT1 sural nerves was studied. For comparison, both normal sural nerves and sural nerves affected by neuropathies of different origin were used. The study was performed by immunohistochemical analysis using antibodies against collagen types I, III, IV, V, and VI and the glycoproteins fibronectin, laminin, vitronectin and tenascin. Up-regulation of collagens, fibronectin and laminin was commonly found in nerve biopsy specimens from patients affected by CMT1 and control diseases, but higher levels of overexpression were usually observed in CMT1 cases. On the other hand, vitronectin and tenascin appeared preferentially induced in CMT1 compared to other pathologies investigated here. Vitronectin, whose expression in normal nerves was limited to perineurial layers and to the walls of epineurial and endoneurial vessels, became strongly and diffusely expressed in the endoneurium in most CMT1 biopsy specimens. The expression of tenascin, confined to the perineurium, to vessel walls and to the nodes of Ranvier in normal nerves, was displaced and extended along the internodes of several nerve fibers in the majority of CMT1 nerves. Thus, compared with our pathological controls CMT1 seemed to determine the most extensive remodeling of peripheral nerve ECM.