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PubMed2006

Actin dynamics at sites of extracellular matrix degradation.

The degradation of extracellular matrix (ECM) by proteases is crucial in physiological and pathological cell invasion alike. In vitro, degradation occurs at specific sites where invasive cells make contact with the ECM via specialized plasma membrane protrusions termed invadopodia. Here we present an extensive morpho-functional analysis of invadopodia actively engaged in ECM degradation and show that they are actin comet-based structures, not unlike the well-known bacteria-propelling actin tails. The relative mapping of the basic molecular components of invadopodia to actin tails is also provided. Finally, a live-imaging analysis of invadopodia highlights the intrinsic long-term stability of the structures coupled to a highly dynamic actin turnover. The results offer new insight into the tight coordination between signalling, actin remodelling and trafficking activities occurring at sites of focalized ECM degradation by invadopodia. In conclusion, invadopodia-associated actin comets are a striking example of consistently arising, spontaneous expression of actin-driven propulsion events that also represent a valuable experimental paradigm.

Actins↗

PubMed1989

Attachment of neuroblastoma cells to extracellular matrix: correlation with metastatic capacity.

Extracellular matrix (ECM) serves important attachment functions during organogenesis in mammalian species. When layered on a plastic surface, ECM extracted from the rat lung, liver, or kidney enhances the attachment of C1300 murine neuroblastoma cells to that surface. Enhanced attachment to ECM by these cells correlates with their potential to form metastatic deposits in vivo. Conversely, neuroblastoma cells selected for increased metastatic potential by in vivo passaging demonstrate enhanced attachment to organ-derived ECM. However, although ECM provides attachment sites for these murine neuroblastoma cells, the attachment is not preferential for any of the organ ECMs tested (lung, liver, kidney). Histopathologic examination of the murine liver, lungs, and kidneys performed 20 to 22 days after intravenous inoculation of C1300 cells reveals notable metastatic seeding in each of these organs, but the liver clearly exhibits a greater degree of replacement by tumor metastases than the lungs or the kidneys. Therefore, the data from the attachment assays, coupled with the histopathologic findings obtained after tumor inoculation, suggest that although the ability to attach to ECM correlates with metastatic potential, additional factors are important in determining the preferential pattern of metastatic disease observed in murine neuroblastoma.

Animals↗

PubMed2002

Local antilaminin antibody treatment alters the rejection pattern of murine cardiac allografts: correlation between cellular infiltration and extracellular matrix.

BACKGROUND: Emerging data place extracellular matrix (ECM) proteins as important elements in lymphocyte positioning and effector function in alloreactive responses. Using a non-vascularized model of allogeneic heart transplantation in Swiss mice, we have observed a correlation between the cellular infiltration and ECM deposition towards the interior of the graft during the kinetics of rejection. METHODS: To confirm the importance of ECM during the rejection process in this model, we treated the transplanted animals with local injections of antilaminin monoclonal antibody and analyzed, by histology and immunohistochemistry, the grafts on day 15, which corresponds to the peak of cellular infiltration and ECM deposition. RESULTS: The treatment with mAb antilaminin decreased the cellular infiltrate and ECM deposition within the grafts, as compared to controls. Moreover, we found a diminished IFN-gamma, TNF-alpha and IL-2 deposition in the transplant area, and a reduced co-localization of these cytokines with laminin. By contrast, the antilaminin treatment increased tenascin deposition, a molecule with immunosuppressive properties, and also caused an increase in apoptosis of the cellular infiltrate. CONCLUSIONS: These data hallmark the importance of laminin, in distinct aspects concerning the events leading to allograft rejection, and also reinforce this molecule as a potential target for immune intervention in organ transplantation.

Animals↗

PubMed1998

Extracellular matrix in renal cell carcinomas.

Extracellular matrix (ECM) may be divided into interstitial matrix and the basement membrane (BM). ECM influences a variety of epithelial cell behaviours, including proliferation, differentiation, and morphogenesis, maybe most widely studied in kidney morphogenesis. In carcinomas, including renal cell carcinomas (RCCs), these properties and interactions of cells with interstitial matrix and BM are disturbed. As a carcinoma with a tendency to spread to distant sites, RCC is an interesting target for the study of epithelial-stromal interactions. Among interstitial collagens, type VI collagen appears to be widely distributed in RCCs. Also EDA-fibronectin (EDA-Fn) as well as tenascin-C (Tn) are important stromal components especially in poorly differentiated carcinomas. BMs of RCC islets and those of tumor blood vessel endothelia may merge in poorly differentiated carcinomas. As a dynamic component of BMs, laminins (Ln) are important in kidney development and RCC progression. Type IV collagen and nidogen, other components of BMs in RCCs, are produced by stromal as well as epithelial cells. ECM proteins may function in RCC progression by binding and regulating the activity of growth factors e.g. transforming growth factor beta 1 and basic fibroblast growth factor. Also the expression of cell surface receptors for ECM is disturbed in RCCs. At least alpha v integrin (Int) and CD44 emerge in renal epithelial cells during malignant transformation. Papillary renal neoplasms differ from RCCs by cell adhesion receptor expression and BM composition as well as by ECM avascularity and capacity to bind growth factors, thus suggesting a distinct property for this renal tumor.

Animals↗

PubMed2006

The functional response of U937 macrophage-like cells is modulated by extracellular matrix proteins and mechanical strain.

Extracellular matrix proteins (ECMs) play a significant role in the transfer of mechanical strain to monocyte-derived macrophages (MDMs) affecting morphological changes in a foreign body reaction. This study investigated how the functional responses of U937 macrophage-like cells differed when subjected to 2 dynamic strain types (nonuniform biaxial or uniform uniaxial strain) while cultured on siloxane membranes coated with either collagen type I or RGD peptide repeats (ProNectin). Biaxial strain caused an increase in intracellular esterase and acid phosphatase (AP) activities, as well as monocyte-specific esterase (MSE) protein levels in cells that were seeded on either uncoated surfaces (shown previously) or collagen, but not ProNectin. Released AP activity, but not released esterase activity, was increased on all surfaces. Biaxial strain increased IL-6, but not IL-8 on all surfaces. When cells were subjected to uniaxial strain, intracellular esterase increased on coated surfaces only, whereas intracellular AP activity was unaffected. Both esterase and AP released activities increased on all surfaces. Uniaxial strain increased the release of IL-6 on all surfaces, but IL-8 on coated surfaces only. This study demonstrated for the first time that ECM proteins could specifically modulate cellular responses to different types of strain. Using this approach with an in vitro cell system may help to unravel the complex function of MDMs in the foreign-body reaction.

Cell Culture Techniques↗

PubMed1993

Immunohistochemical localization of extracellular matrix in perivillous fibrinoid of normal human term placenta.

The extracellular matrix of perivillous fibrinoid in normal human term placenta was investigated by means of the indirect immunofluorescent technique. Polyclonal antibodies to collagen types I, III, IV, V, fibronectin, fibrinogen, laminin, entactin and heparan sulphate proteoglycan and monoclonal antibodies BC-1, IST-9 and IST-4 to human fibronectin were used. The antigens can be grouped according to their presence in fibrinoid as abundant (fibrinogen, fibronectin, heparan sulphate proteoglycan, basement membrane collagen types IV and V), absent (laminin) and variable between fibrinoids (interstitial collagen types I and III, entactin). Our results also demonstrate that fibronectin in fibrinoid originates from placental cells (presumably cytotrophoblast). Monoclonal antibodies BC-1 and IST-9 specific to tissue fibronectin do not stain neighbouring placental extracellular matrix but do bind to fibrinoids on the same sections. Work by other authors has presented evidence that fibrin actually originates from maternal blood and even makes an attempt to substitute the term "fibrinoid" for "fibrin deposition". Our data on the composition of perivillous fibrinoids and the abundance of extracellular matrix components do not support this view and suggest that fibrinoid is a more relevant term for this interesting phenomenon, which deserves further investigation.

Adult↗

PubMed2003

A genomewide survey of developmentally relevant genes in Ciona intestinalis. X. Genes for cell junctions and extracellular matrix.

Cell junctions and the extracellular matrix (ECM) are crucial components in intercellular communication. These systems are thought to have become highly diversified during the course of vertebrate evolution. In the present study, we have examined whether the ancestral chordate already had such vertebrate systems for intercellular communication, for which we have searched the genome of the ascidian Ciona intestinalis. From this molecular perspective, the Ciona genome contains genes that encode protein components of tight junctions, hemidesmosomes and connexin-based gap junctions, as well as of adherens junctions and focal adhesions, but it does not have those for desmosomes. The latter omission is curious, and the ascidian type-I cadherins may represent an ancestral form of the vertebrate type-I cadherins and desmosomal cadherins, while Ci-Plakin may represent an ancestral protein of the vertebrate desmoplakins and plectins. If this is the case, then ascidians may have retained ancestral desmosome-like structures, as suggested by previous electron-microscopic observations. In addition, ECM genes that have been regarded as vertebrate-specific were also found in the Ciona genome. These results suggest that the last common ancestor shared by ascidians and vertebrates, the ancestor of the entire chordate clade, had essentially the same systems of cell junctions as those in extant vertebrates. However, the number of such genes for each family in the Ciona genome is far smaller than that in vertebrate genomes. In vertebrates these ancestral cell junctions appear to have evolved into more diverse, and possibly more complex, forms, compared with those in their urochordate siblings.

Animals↗

PubMed1998

Oligodendrocytes utilize a matrix metalloproteinase, MMP-9, to extend processes along an astrocyte extracellular matrix.

Matrix metalloproteinases (MMPs), the key effectors of extracellular matrix remodeling, have been demonstrated to regulate the extension of neurites from neuronal cell bodies. In this report we have addressed the hypothesis that oligodendrocytes (OLs) may utilize a similar mechanism in extending their processes during the initial phase of myelination. Furthermore, given our previous findings linking protein kinase C (PKC) to the OL process outgrowth, we tested the postulate that this signal transduction pathway may regulate MMPs and thus the process outgrowth phenotype. We demonstrate that in response to pharmacologic activators of PKC, cultured human OLs augment their process extension with a concomitant increase in the activity of an MMP, MMP-9, as measured by gelatin zymography. Similarly, the phorbol ester-enhanced process extension and increased MMP-9 activity were both inhibited by calphostin C, a selective PKC inhibitor. Also, MMP inhibitors such as 1,10-phenanthroline and synthetic dipeptides that inactivate the MMP catalytic site negated the 4beta-phorbol-12,13-dibutyrate (PDB)-mediated process extension, further supporting the key role of MMPs in process extension in vitro. Finally, the elevation of MMP-9 protein expression in the mouse corpus callosum, a tissue rich in OL and myelin, coincided with the previously documented temporal increase in myelination that occurs postnatally. Taken together, these data suggest that MMP-9 constitutes an important mediator of OL process outgrowth, and that this protease in turn can be regulated by PKC. The results are relevant not only to the initial steps of myelination during development, but also to the attempted remyelination that has been shown to occur in pathologic conditions such as MS.

Animals↗

PubMed2000

Extracellular matrix components prevent lipopolysaccharide-induced bovine arterial endothelial cell injury by inhibiting p38 mitogen-activated protein kinase.

The effect of extracellular matrix components on lipopolysaccharide-induced vascular endothelial cell injury was studied by using lipopolysaccharide-susceptible bovine aortic endothelial cells. For evaluation of lipopolysaccharide-induced injury, we estimated DNA synthesis and cell detachment of bovine aortic endothelial cells in cultures using extracellular matrix components-coated plastic dishes. Among extracellular matrix components, matrigel almost completely inhibited the reduction in DNA synthesis and the enhancement in cell detachment of bovine aortic endothelial cells in cultures with lipopolysaccharide. The lipopolysaccharide-induced injury was also inhibited by coating with type IV collagen, gelatin, fibronectin, laminin, vitronectin, and heparin sulphate proteoglycan. Extracellular matrix components capable of preventing lipopolysaccharide-induced bovine aortic endothelial cells injury coincidentally inhibited the phosphorylation of p38 mitogen-activated protein kinase in lipopolysaccharide-treated bovine aortic endothelial cells. SB203580, a specific inhibitor of p38 mitogen-activated protein kinase, also prevented the reduction in DNA synthesis and the enhancement in cell detachment of bovine aortic endothelial cells in cultures with lipopolysaccharide. It was therefore suggested that extracellular matrix components might protect bovine aortic endothelial cells from lipopolysaccharide-induced injury through inhibiting the activation of p38 mitogen-activated protein kinase.

Animals↗

PubMed2000

Effects of boron derivatives on extracellular matrix formation.

Boric acid solution (3%) dramatically improves wound healing through action on the extracellular matrix, a finding that has been obtained in vitro. Consequently, investigations are presently underway to produce boronated compounds having a therapeutical effectiveness similar to that of boric acid. On the basis of experimental results obtained with boric acid, we examined the effects of boron derivatives on extracellular matrix formation and degradation and analyzed their potential toxicity by using two biological models (chick embryo cartilage and human fibroblasts). The four boron derivatives tested in this study (triethanolamine borate; N-diethyl-phosphoramidate-propylboronique acid; 2,2 dimethylhexyl-1,3-propanediol-aminopropylboronate and 1,2 propanediol-aminopropylboronate) mimicked the effects of boric acid. They induced a decrease of intracellular concentrations in extracellular matrix macromolecules (proteoglycans, proteins)-associated with an increase of their release in culture medium and stimulated the activity of intra- and extracellular proteases. Similarly to boric acid, these actions occurred after exposure of the cells to concentrations of all boron derivatives without apparent toxic effects. The compounds were found to be more toxic than boric acid itself when concentrations were calculated according to their molecular weight. Nevertheless, these in vitro preliminary results demonstrate effects of boron derivatives that may be of therapeutic benefit in wound repair.

Animals↗

PubMed1987

Early functional differentiation in the chick embryonic disc: interaction between mechanical activity and extracellular matrix.

The mechanical behaviour of ectodermal cells in the area opaca and the supracellular organization of fibronectin in the adjacent extracellular matrix were studied in whole chick blastoderms developing in vitro. The pattern of spontaneous mechanical activity and its modification by immunoglobulins against fibronectin were determined using a real-time image-analysis system. The pattern of fibronectin was studied using immunocytochemical techniques. It was found that the ectodermal cells in the area opaca actively develop a radially oriented contraction, which leads to a distension of the area pellucida from which the embryo develops. Abnormally increased tension resulted in perturbations of gastrulation and neurulation. An optimized mechanical equilibrium within the blastoderm seems to be necessary for normal development. Anti-fibronectin antibodies applied to the basal side of the blastoderm led rapidly and reversibly to an increase of tension in the contracted cells. This observation indicates that modifications of the extracellular matrix can be transmitted to cytoskeletal elements within adjacent cells. The extracellular matrix of the area opaca contains fibronectin arranged in radially oriented fibrils. This orientation corresponds to the direction of migration of the mesodermal cells. Interestingly, the radial pattern of fibronectin is found in the regions where the ectodermal cells are contracted and develop radially oriented forces. This observation suggests that the supracellular assembly of the extracellular materials could be influenced by the mechanical activity of adjacent cells. Possible modulations of the supracellular organization of extracellular matrix by other factors, e.g. diffusible metabolites, is also discussed. The presence of characteristically organized extracellular matrix components, of spatially differentiated cell activities and of reciprocal interactions between them makes the young chick blastoderm an excellent system for physiological studies of the coordinated cellular activities that lead to changes in form, complexity and function.

Animals↗

PubMed2001

Extracellular matrix in development of the early embryo.

The extracellular matrix interacts with cells and promotes and regulates cellular functions such as adhesion, migration, proliferation, differentiation, and morphogenesis. Extracellular molecules are linked to one another by multiple binding domains and form a stable, multifunctional matrix. Cells respond to the extracellular matrix through plasma membrane receptors, which include integrin and non-integrin receptors. The regulation of these interactions requires the coordination of a multiplicity of signals both spatially and temporally.

Animals↗

PubMed2004

[Effects of growth factors and extracellular matrix on proliferation and differentiation of fetal liver progenitor cell in vitro].

OBJECTIVE: Liver development needs a number of growth factors and components of the extracellular matrix. The study is to explore how growth factors and extracellular matrix regulate proliferation and differentiation of fetal liver progenitor cell. METHODS: We demonstrate isolation of hepatic progenitor/stem cells from ED 14.5 SD rat liver, which contains a large number of hepatoblasts. Proliferation assay-3H thymidine incorporation was used to detect the effect of growth factors on proliferation of hepatic progenitor cell. Growth factor and extracellular matrix were added and stem cell clone formation was counted. Mark of bile duct and hepatocyte were detected with double-marker immunocytochemistry. RESULTS: Progenitor liver cells displayed clonogenic capacity, expressed markers of hepatocytes and bile duct cells and G-6-P. HGF, EGF can accelerate DNA synthesis and stem cell clone formation of hepatic progenitor cell. Extracellular matrix collagen I, collagen IV or laminin were essential for formation of stem cell clone. Single cell culture needed HGF, EGF, extracellular matrix and supernatant of mix cell (which contained fetal parenchymal cells, mesenchymal cells and hematopoietic cells) culture. CONCLUSION: Growth factors especially HGF and EGF play crucial role in proliferation and differentiation of liver progenitor cell. Some factors secreted from mesenchymal cell and hematopoietic cells may be involved.

Animals↗

PubMed1996

Immunohistochemical localization of extracellular matrix proteins in cerebral vessels in chronic hypertension.

Vascular hypertrophy or vascular remodeling are both associated with an increase in the extracellular matrix of cerebral arteries and arterioles in chronic hypertension. Rats with chronic renal hypertension were studied to determine whether the extracellular matrix proteins--collagen IV, laminin, and fibronectin--are increased in the thick-walled cerebral vessels in brain and those associated with areas of blood-brain barrier (BBB) breakdown to protein. The latter was detected by extravasation of endogenous serum proteins in brain. Serum proteins and the extracellular matrix proteins--fibronectin, laminin, and collagen IV--were detected by immunohistochemistry. Hypertensive rats having blood pressures over 150 mm Hg showed mild to moderate degrees of mural thickening of pial and intracerebral arterioles. In addition, these vessels demonstrated increased immunoreactivity with collagen IV, fibronectin, and laminin antisera. This occurred concomitant with the development of hypertension and prior to the observation of BBB breakdown to protein. Four rats having mean maximum systolic blood pressures in excess of 220 mm Hg developed multifocal areas of increased vascular permeability to endogenous serum proteins in the boundary zones of the territories supplied by the major cerebral arteries. The arterioles in these areas showed a severe degree of vascular thickening, which was due to medial hyperplasia/hypertrophy and increased mural deposition of serum proteins and the extracellular matrix proteins--laminin, fibronectin, and collagen IV. This study demonstrates that extracellular matrix proteins play an important role in the vascular response to increased intraluminal pressure. However, since this change occurs in diseases in the absence of hypertension it should be regarded as a nonspecific response of cellular components of vessel walls to injury.

Animals↗

PubMed2000

Beneficial effects of retinoic acid on extracellular matrix degradation and attachment behaviour in follicular thyroid carcinoma cell lines.

The prognosis of patients with metastasised follicular thyroid carcinoma (FTC) is limited, necessitating the search for new treatment options. Beneficial effects of retinoids have been suggested in thyroid cancer and the present study was performed to investigate the effects of retinoic acid (RA) on important determinants of metastatic behaviour in FTC: the disengagement of tumour cells from the primary tumour and the degradation of extracellular matrix, focusing on the role of the plasmin activation system and the integrin and E-cadherin families of attachment molecules. Three FTC cell lines were studied: FTC-133, derived from the primary tumour; and FTC-236 and FTC-238, derived from metastases. FTC cell lines were cultured with 0.1, 1 and 10 microM 13-cis-RA or with the solvent DMSO for 1 and 5 days. Extracellular matrix degradation by these cell lines was studied by assessing the 48-h release of radioactivity from (35)S-methionine labelled extracellular matrix proteins synthesised by the MC3T3 cell line coated onto plastic. The involvement of constituents of the plasmin activation system was investigated by semi-quantitative RT-PCR and zymography. Attachment to extracellular matrix was studied by determining the number of adhering FTC cells to extracellular matrix coated onto plastic, 3 h after seeding. The involvement of attachment molecules was studied by RT-PCR with primers for integrin subclasses and E-cadherin and immunofluorescence for E-cadherin. Five days culturing with 10 microM RA reduced the degradation of extracellular matrix significantly in all cell lines: FTC-133 by 35%, FTC-236 by 74% and FTC-238 by 31%. Zymography revealed diminished activity of urokinase type plasminogen activator (uPA) in FTC-236 and FTC-238, but not in FTC-133 cultured with RA. mRNA expression of the uPA receptor was diminished in FTC-236. In the attachment assay, 10 microM RA for 5 days increased the number of adherent cells to extracellular matrix significantly by 91% in FTC-133, 64% in FTC-236 and 87% in FTC-238. No effects of RA on integrin or E-cadherin mRNA expression were observed. Immunofluorescence, however, revealed enhanced organisation of E-cadherin along the cell membrane by RA treatment. In conclusion, the present study demonstrates beneficial effects of RA on important determinants of metastatic behaviour in FTC cell lines, e.g. decreased degradation of extracellular matrix which may in part be explained by effects on the plasmin activation system and enhanced attachment to extracellular matrix. These findings may add to the explanations for beneficial effects of retinoids in thyroid cancer.

Adenocarcinoma, Follicular↗

PubMed2002

[Extracellular matrix metalloproteinases--perspectives of their use in medicine].

Extracellular matrix turnover disturbances are implicated in many human diseases. Matrix Metalloproteinases (MMP) are believed to play a pivotal role in maintaining the intricate balance between extracellular matrix synthesis and degradation. These enzymes are active in the cleavage of many matrix proteins. There is evidence that matrix metalloproteinases activity changes in many pathological conditions, including inflammatory and degenerative disorders as well as tumour progression and metastases. This review focuses on the recent view on physiological and pathological function of MMPs. Authors aimed also to show the putative role of matrix metalloproteinases as a diagnostic tool in future medicine.

Biomarkers, Tumor↗

PubMed1990

Human trophoblast-extracellular matrix (ECM) interactions in vitro: ECM thickness modulates morphology and proteolytic activity.

Trophoblast invasion of the uterine extracellular matrix, a critical process for human implantation and uteroplacental vascular development, is a striking example of controlled invasiveness. To examine cellular behavior relevant to this process, human trophoblasts were cultured on (i) Millicell filters prelayered with Matrigel and (ii) coverslips precoated with a gentle slope of Matrigel (Matribeach). Histologic sections of the Millicell system demonstrated significant invasion. However, on Matribeach the cells exhibited markedly different characteristics depending on the thickness of the Matrigel. On zone 1 (1-4 microns thick), flat aggregates and syncytia were seen. In contrast, cells on zone 2 (4-14 microns) formed rounded aggregates with intercellular processes. In this zone, prominent degradation of pericellular Matrigel proteins was assessed by both light microscopy and scanning electron microscopy. Treatment with 8-bromo-cAMP inhibited this proteolytic process. On zone 3 (14-60 microns), unicellular trophoblasts or small aggregates caused minimal matrix degradation. JEG-3 human choriocarcinoma cells exhibited similar morphologic and degradative properties on Matribeach, but zone 2 proteolysis was not affected by 8-bromo-cAMP. Our results suggest that extracellular matrix thickness has profound effects on cellular morphology and proteolytic activity. Furthermore, while both normal and malignant human trophoblasts can degrade extracellular matrix proteins, only normal trophoblast extracellular matrix degradation is inhibited by 8-bromo-cAMP.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed2003

Poly(hydroxybutyrate-co-hydroxyhexanoate) promoted production of extracellular matrix of articular cartilage chondrocytes in vitro.

The present investigation describes the production of extracellular matrix of rabbit articular cartilage chondrocytes grown on scaffolds of polyhydroxybutyrate (PHB) blended with poly(hydroxybutyrate-co-hydroxyhexanoate) (PHBHHx) for up to 7 days. The mRNA level of type II collagen of chondrocytes seeded on all scaffolds consisting of PHBHHx were obviously higher than that of PHB-only scaffold throughout the culture period, suggesting the positive effect of PHBHHx on extracellular matrix production. Second-harmonic generation (SHG) imaging technique, combined with confocal fluorescence microscopy (CFM) revealed that PHBHHx in PHB scaffold provided better surface properties for anchoring type II collagen filaments and their penetration into internal layers of the scaffolds. Glycosaminoglycan (GAG), a major composition of extracellular matrix, showed a sharp increase in construct of 1:2 PHB/PHBHHx scaffold after 7 day cultivation, while only a small increase was observed in all other tested scaffolds. At the same time, total collagen contents in all scaffolds containing PHBHHx increased with time, with the maximum collagen production of 742.1+/-99.2mg/g dry weight observed in construct of 1:2 PHB/PHBHHx scaffold inoculated for 7 days, this was almost 4-fold higher than that in scaffold of PHB only. It appears that the presence of right proportion of PHBHHx in the composite system of PHB/PHBHHx highly favored the production of extracellular matrix of articular cartilage chondrocytes.

3-Hydroxybutyric Acid↗