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At least 253 records · Page 14Linked to original sources
PubMed2002

Novel cell-scaffold interactions encountered in tissue engineering: contractile behavior of musculoskeletal connective tissue cells.

Methods employed in the course of tissue engineering often offer unique opportunities to observe cell-matrix interactions that cannot otherwise be viewed. These observations may provide insights into cell behavior than can contribute important new knowledge about cell biology. One such set of observations led to the discoveries that musculoskeletal connective tissue cells express a contractile muscle actin isoform, alpha-smooth muscle actin, and can contract. This knowledge may help to explain how these cells generate forces required for certain physiological and pathological functions, and this information may inform future approaches to regulate this function to advance tissue engineering. Tissue engineering science is thus emerging as an importance force that can both contribute to cell and molecular biology and add to the fund of knowledge supporting the production of tissue in vitro or in vivo to improve the management of a wide variety of disorders.

Actins↗
PubMed2006

[Connective tissue dysplasias (hereditary collagenopathies)].

Connective tissue dysplasia (hereditary collagenopathy) presents a group of genetically heterogenous and clinically polymorphic pathological conditions, associated with disturbances in the forming of connective tissue during the embryonal and postnatal periods. Differentiated dysplasias include monofactor diseases with an established genetic defect and clear clinical symptoms, such as Marfan's syndrome, Ehlers-Danlo's syndrome, and osteogenesis imperfecta. The variants of non-differentiated hereditary dysplasias include primary mitral valve prolapse and other minor heart anomalies, tracheobronchial dyskinesia, visceroptosis, join hypermobility, congenital chest deformations, "weakness" of the ligamentous apparatus of the foot and the spine, and a range of other prevalent pathological changes. The author adduces his own observation of a patient with Marfan's syndrome.

Adult↗
PubMed2003

[Expression of connective tissue growth factor gene in the hypertrophic scar and keloid tissue].

OBJECTIVE: To explore the effect of connective tissue growth factor on the pathogenesis of hypertrophic scar and keloid tissue. METHODS: The content of hydroxyproline was determined and the expression of connective tissue growth factor gene was detected by the reverse transcription-polymerase chain reaction and image analysis technique in 5 normal skins, 15 hypertrophic scars and 7 keloid tissues. RESULTS: The contents of hydroxyproline in the hypertrophic scar (84.10 +/- 1.76) and keloid tissue (92.38 +/- 2.04) were significantly higher than that of normal skin tissue (26.52 +/- 4.10) (P < 0.01). The index of connective tissue growth factor mRNA in the hypertrophic scar (0.78 +/- 0.63) and keloid tissue (0.84 +/- 0.04) were higher than that of normal skin tissue (0.09 +/- 0.25) (P < 0.01). CONCLUSION: Connective tissue growth factor may play an important role in promoting the fibrotic process of hypertrophic scar and keloid tissue.

Adolescent↗
PubMed2004

TGF beta1 and PDGF AA override collagen type I inhibition of proliferation in human liver connective tissue cells.

BACKGROUND: A marked expansion of the connective tissue population and an abnormal deposition of extracellular matrix proteins are hallmarks of chronic and acute injuries to liver tissue. Liver connective tissue cells, also called stellate cells, derived from fibrotic liver have been thoroughly characterized and correspond phenotypically to myofibroblasts. They are thought to derive from fat-storing Ito cells in the perisinusoidal space and acquire a contractile phenotype when activated by tissue injury. In the last few years it has become evident that several peptide growth factors such as PDGF AA and TGF-beta are involved in the development of fibrosis by modulating myofibroblast proliferation and collagen secretion. The fact that during the development of chronic fibrosis there is concomitant deposition of collagen, a known inhibitory factor, and sustained cell proliferation, raises the possibility that stellate cells from chronic liver fibrosis patients fail to respond to normal physiologic controls. METHODS: In this study we address whether cells from fibrotic liver patients respond to normal controls of proliferation. We compared cell proliferation of primary human liver connective tissue cells (LCTC) from patients with liver fibrosis and skin fibroblasts (SF) in the presence of collagens type I and IV; TGF-beta, PDGF AA and combinations of collagen type I and TGF-beta or PDGF AA. RESULTS: Our results indicate that despite displaying normal contact and collagen-induced inhibition of proliferation LCTC respond more vigorously to lower concentrations of PDGF AA. In addition, we show that collagen type I synergizes with growth factors to promote mitogenesis of LCTC but not SF. CONCLUSIONS: The synergistic interaction of growth factors and extracellular matrix proteins may underlie the development of chronic liver fibrosis.

Cell Line↗
PubMed1988

[Development of a small caliber vascular graft using a connective tissue tube with temporary antithrombogenicity].

A connective tissue tube containing collagen fibrils and capillary blood vessels is an ideal material for artificial artery, since the collagen fibrils compose an excellent supporting framework for cell migration and proliferation and the endothelial cells of the capillary can be the origin of the endothelialization of the graft. However, its thrombogenicity has remained a problem. This experiment was designed to develop a small caliber (3mm) vascular graft using an autogenous connective tissue provided with temporary antithrombogenicity. A tube knitted of ultra-fine polyesters was implanted subcutaneously in the back of mongrel dogs for three weeks. Thus accomplished connective tissue grafts were heparinized ionically in vitro, using cross-link agents. Then the treated grafts, 5-6 cm in length and 3mm in diameter, were segmentally replaced with bilateral carotid arteries. During the follow-up period up to 55 days, 7 of 8 grafts (88%) were patent. Histological examinations revealed that there was no thrombus and the neointima formation with a lining of endotherial cells was completed, extending overall length of the grafts. Thus, newly devised hybrid type of connective tissue graft is thought to be usefull for a replacement for arteries with a small caliber.

Animals↗
PubMedDate not supplied

[Human lung connective tissue in postnatal ontogeny].

Changes of the connective tissue structures, appearing during all postnatal ontogenesis stages were studied in 147 human lung specimens of different age groups (from newborns up to 82-year-olds). Qualitative and quantitative composition of connective tissue structures changes with the age which leads to the lateral aggregation of the fibers and growth of the general mass of the connective tissue. Heterochronia of the age variability manifestations in different regions of the lung framework was demonstrated. The original age transformations of connective tissue structures are characteristic for the basal lung regions. With the exception of perivasal connective tissue, similar changes in the region of the lung apexes appear 3-5 years later. This gives an opportunity to distinguish three anatomic zones in the lungs in an apico-basal direction, characterising the local nature of the age changes manifestations.

Adolescent↗
PubMed1998

Silicon analysis of breast and capsular tissue from patients with saline or silicone gel breast implants: II. Correlation with connective-tissue disease.

The silicone breast implant controversy rages on. Recent work has demonstrated that normal or baseline breast tissue silicon levels in women who had had no prior exposure to any type of breast implant may be as high as 446 microg/gm of tissue. These data ranged from 4 to 446 microg/gm of tissue, with a median of 27.0 microg/gm of tissue. In addition, numerous other epidemiologic and rheumatologic studies have demonstrated no association between silicone breast implants and any connective-tissue diseases. Despite these reports, the use of silicone implants remains restricted. The present study measured breast and capsular tissue silicon levels from 23 breasts in 14 patients with saline implants, and from 42 breasts in 29 patients with silicone implants. No patient in the saline implant group presented with signs or symptoms of connective-tissue disease. Patients with silicone implants, however, were divided into three groups based on the presence or absence of signs or symptoms of connective-tissue disease: group I, no symptoms or signs; group II, + symptoms, no signs; and group III, + symptoms, + signs. Six patients in group III were diagnosed with a specific connective-tissue disease, including systemic lupus erythematosus, rheumatoid arthritis, or scleroderma. The most common indications for implant removal or exchange were capsular contracture and implant rupture, although 41 percent of patients with silicone implants expressed media-related concern over the implant issue. The most common symptoms described by patients in groups II and III were joint pain and stiffness, arm pain and numbness, and fatigue. In all groups, capsular tissue silicon levels were significantly greater than breast tissue levels. This finding may indicate that the capsule serves as a barrier to the distribution of silicone from the implant into adjacent breast tissue. Although breast tissue silicon levels in patients with silicone implants were not significantly greater than those in patients with saline implants (p = 0.48), capsular tissue levels in patients with silicone implants were, indeed, significantly greater than those in patients with saline implants (p < 0.001). However, no statistically significant differences in tissue silicon levels were observed with relation to the presence or absence of connective-tissue disease signs or symptoms in patients with silicone implants (groups I to III). Therefore, these data strengthen the conclusion that there is no association between tissue silicon levels and connective-tissue disease.

Breast↗
PubMed1989

The influence of subepithelial connective tissues on epithelial proliferation in the adult mouse.

Subepithelial connective tissue is capable of modulating the pattern of histodifferentiation of stratified epithelia from adult animals, but it is not known whether the supporting connective tissue also influences epithelial proliferative activity. Epithelial and connective tissues of murine skin and oral mucosa, differing in their morphology and proliferative activity, were separated and heterotypically recombined prior to grafting to histocompatible hosts. After 3 or 8 weeks in situ, mitotic activity was determined following the administration of vinblastine sulfate. Although the mitotic activity in each of the epithelia could be modulated by some connective tissues, there was no distinct pattern of behavior. In combination with connective tissues from tongue or palate, the ear epidermis acquired a significantly increased mitotic activity. In contrast, when oral epithelia with high mitotic activity were recombined with dermal connective tissue, there was usually a significant reduction in proliferative activity. As there was no apparent association between mitotic activity and the induced changes in either organization or histodifferentiation, it is suggested that subepithelial connective tissue is capable of directly influencing the mitotic activity in the overlying epithelium.

Animals↗
PubMedDate not supplied

[The relation of the biological value of meat proteins to their content of connective tissue].

The influence of connective tissue on the biological value of meat products, manufactured from hashed meat, was studied in experiments on growing rats. It was shown that collagen level increase from 6.1 to 14.5% of the total amount of meat proteins improved the growth-mass characteristics of the animals. The actual biological value and the absolute protein utilization had a tendency to lowering, although the difference was not statistically significant. At the same time the effectiveness of tissue protein biosynthesis was not lowered. A conclusion has been made that the results of animal experiments correlate with the clinical data on the positive effect of the increase up to 15% (by protein) of collagen content on the anabolic action of hashed meat protein in humans. A further increase of the connective tissue amount leads to its diminished biological value.

Animals↗
PubMed2002

The structure and functional significance of variations in the connective tissue within muscle.

The amount of intramuscular connective tissue (IMCT) and its morphological distribution is highly variable between muscles of differing function. The functional roles of this component of muscle have been poorly understood, but a picture is gradually emerging of the central role this component has in growth, transmission of mechanical signals to muscle cells and co-ordination of forces between fibres within a muscle. The aim of this review is to highlight recent advances that begin to show the functional significance of some of the variability in IMCT. IMCT has a number of clearly defined roles. It patterns muscle development and innervation, and mechanically integrates the tissue. In developing muscles, proliferation and growth of muscle cells is stimulated and guided by cell-matrix interactions. Recent work has shown that the topography of collagen fibres is an important signal. The timing and rates of expression of connective tissue proteins also show differences between muscles. Discussion of mechanical roles for IMCT has traditionally been limited to the passive elastic response of muscle. However, it is now clear that IMCT provides a matrix to integrate the contractile function of the whole tissue. Mechanical forces are co-ordinated and passed between adjacent muscle cells via cell-matrix interactions and the endomysial connective tissue that links the cells together. An emerging concept is that division of a muscle into fascicles by the perimysial connective tissue is related to the need to accommodate shear strains as muscles change shape during contraction and extension.

Animals↗
PubMed1978

The hand in mixed connective tissue disease.

The mixed connective tissue disease syndrome has been described in the medical literature. The clinical and serological characteristics of the syndrome are defined in this paper. The hands of these patients differ from the hands of patients with systemic lupus, rheumatoid arthritis, or systemic sclerosis. In 10 patients there were no erosive changes on radiological examination and all 10 patients had Raynaud's phenomenon. The most striking finding was tightness in the flexors. Mild cases of flexor tightness improved with systemic steroids. One patient with severe flexor tightness required surgical release of adhesions from a chronic inflammatory process of fascia, muscle, and tenosynovium. Biochemical studies showed an abnormal collagen pattern that may be distinct for mixed connective tissue disease.

Adolescent↗
PubMed2005

[Interstitial lung disease in connective tissue disorders].

Interstitial lung diseases (ILD) associated with connective tissue disorders differ from idiopathic ILD in several aspects, although most of them are comparable. In most patients, ILD occurs during the course, or at the time of diagnosis of connective tissue disease. Opportunistic pulmonary infections, together with adverse effects of treatment should always be discussed. The prevalence of ILD varies among the different connective tissue disorders. Thus, ILD is frequently encountered in patients with systemic sclerosis and to a lesser degree in patients with myositis. As compared to idiopathic ILD, histopathological aspects of ILD associated with connective tissue diseases are more frequently those of non-specific interstitial pneumonia, whereas usual interstitial pneumonia is rare. Other ILD, such as organized pneumonia, interstitial lymphoid pneumonia, diffuse alveolar damage and alveolar hemorrhage are occasionally encountered. ILD must be detected early in the course of collagen disorders by performing computed tomodensitometry and pulmonary function tests. The prognosis of connective tissue associated ILD is better than that of idiopathic ILD. The treatment requires corticosteroids and/or immunosuppressants, depending on the nature of the associated connective tissue disease and ILD progression.

Adrenal Cortex Hormones↗
PubMed1988

Comparative connective tissue structure-function relationships in biologic pumps.

A complex connective tissue framework exists in mammalian hearts that surrounds and interconnects individual myocytes and fascicles of cells. Recent evidence suggests that this connective tissue plays a role in maintaining shape, modulating contractile forces, and mediating elastic recoil during cavity filling and contraction. In order to analyze the involvement of connective tissue in pump contraction and recoil, we examined silver impregnated connective tissue in rat hearts which spontaneously jet through fluid ex vivo by contracting their cavities forcefully and then sucking fluid for the next cycle, and compared them to frog hearts which beat actively under the same conditions, but do not demonstrate jet propulsion. A further analysis was carried out in unrelated but analogous models: the squid and octopus. The former jets rapidly through the ocean, while the latter moves sinuously along the seabed. We observed highly interconnected myocytes in the rat heart, whereas frog myocytes are individually wrapped by connective tissue but are not interconnected. The squid mantle muscle is surrounded by a complex connective tissue grid that is tethered to each muscle cell, whereas the octopus mantle muscle cells are surrounded by connective tissue but are not tethered. These observations suggest that myocyte connective tissue tethering may be necessary for muscle cavities to generate forceful and coordinated contractions sufficient for rapid ejection and suction of fluid.

Animals↗
PubMed1987

Chondrosarcoma of the calcaneum and massive soft tissue calcification in a patient with hereditary and acquired connective tissue diseases.

We describe the first case of the coexistence of the hereditary connective tissue disorder multiple exostoses (HME) and an acquired connective tissue disorder manifest by the overlap of dermatomyositis (DM), scleroderma (PSS), high titre speckled pattern antinuclear antibodies, and increased antibodies to double stranded deoxyribonucleic acid (DNA). Furthermore this patient developed chondrosarcoma of the calcaneum (an unusual site for this malignancy) and massive soft tissue calcification (an unusual feature of PSS, adult DM, and systemic lupus erythematosus (SLE)).

Bone Neoplasms↗
PubMed2002

Connective tissue growth factor: expression in human skin in vivo and inhibition by ultraviolet irradiation.

Connective tissue growth factor, which is induced by transforming growth factor beta, has been reported to mediate the stimulatory actions of transforming growth factor beta on type I procollagen synthesis. Connective tissue growth factor is expressed in fibrotic disease such as scleroderma, where it is believed to promote abnormal deposition of collagen. Connective tissue growth factor expression has not been described in normal human skin or cultured skin cells, however. We report here that connective tissue growth factor mRNA is constitutively expressed in normal human skin. In situ hybridization demonstrated that connective tissue growth factor mRNA was expressed in keratinocytes throughout the epidermis and in dermal cells. Quantitative real-time reverse transcription polymerase chain reaction revealed that the level of connective tissue growth factor mRNA in the epidermis and dermis of normal human skin was comparable to the level of housekeeping gene 36B4. Ultraviolet irradiation (2 minimal erythema dose, UVB/A2 source) reduced connective tissue growth factor mRNA expression throughout the epidermis and dermis in normal human skin in vivo. Connective tissue growth factor mRNA was reduced (30%) within 4 h post ultraviolet irradiation, and remained reduced (50%) 8-24 h post ultraviolet. Connective tissue growth factor mRNA and protein were also constitutively highly expressed in normal cultured human skin keratinocytes and fibroblasts. Ultraviolet irradiation of cultured normal human skin fibroblasts resulted in a time-dependent inhibition of connective tissue growth factor mRNA expression. At 24 h post ultraviolet, connective tissue growth factor mRNA expression was reduced 80%. Transforming growth factor beta1 rapidly induced connective tissue growth factor mRNA levels (5-fold within 4 h) in skin fibroblasts, but not keratinocytes, and this induction was attenuated 80% by ultraviolet irradiation. Electrophoretic mobility shift assays demonstrated that ultraviolet irradiation reduced protein binding to the transforming growth factor beta/Smad responsiveness elements in the connective tissue growth factor gene promoter, in human skin in vivo and human skin fibroblasts. Constitutive expression of connective tissue growth factor in normal human skin suggests that it is a physiologic regulator of procollagen synthesis. Ultraviolet reduction of connective tissue growth factor expression may contribute to reduced procollagen synthesis observed in ultraviolet-irradiated normal human skin and human skin fibroblasts.

Adult↗
PubMed1987

Ultrastructural changes in the intestinal connective tissue of Xenopus laevis during metamorphosis.

Ultrastructural changes in the intestinal connective tissue of Xenopus laevis during metamorphosis have been studied. Throughout the larval period to stage 60, the connective tissue consists of a few immature fibroblasts surrounded by a sparse extracellular matrix: few collagen fibrils are visible except close to the thin basal lamina. At the beginning of the transition from larval to adult epithelial form around stage 60, extensive changes are observed in connective tissue. The cells become more numerous and different types appear as the collagen fibrils increase in number and density. Through gaps in the thickened and extensively folded basal lamina, frequent contacts between epithelial and connective tissue cells are established. Thereafter, with the progression of fold formation, the connective tissue cells become oriented according to their position relative to the fold structure. The basal lamina beneath the adult epithelium becomes thin after stage 62, while that beneath the larval epithelium remains thick. Upon the completion of metamorphosis, the connective tissue consists mainly of typical fibroblasts with definite orientation and numerous collagen fibrils. These observations indicate that developmental changes in the connective tissue, especially in the region close to the epithelium, are closely related spatiotemporarily to the transition from the larval to the adult epithelial form. This suggests that tissue interactions between the connective tissue and the epithelium play important roles in controlling the epithelial degeneration, proliferation, and differentiation during metamorphic climax.

Animals↗
PubMed2006

Connective tissue: a body-wide signaling network?

Unspecialized "loose" connective tissue forms an anatomical network throughout the body. This paper presents the hypothesis that, in addition, connective tissue functions as a body-wide mechanosensitive signaling network. Three categories of signals are discussed: electrical, cellular and tissue remodeling, each potentially responsive to mechanical forces over different time scales. It is proposed that these types of signals generate dynamic, evolving patterns that interact with one another. Such connective tissue signaling would be affected by changes in movement and posture, and may be altered in pathological conditions (e.g. local decreased mobility due to injury or pain). Connective tissue thus may function as a previously unrecognized whole body communication system. Since connective tissue is intimately associated with all other tissues (e.g. lung, intestine), connective tissue signaling may coherently influence (and be influenced by) the normal or pathological function of a wide variety of organ systems. Demonstrating the existence of a connective signaling network therefore may profoundly influence our understanding of health and disease.

Animals↗