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PubMed1976

Action of human hyperlipemic sera on the biosynthesis of intercellular matrix macromolecules in aorta organ cultures.

Explants from rabbit aortic media were incubated in MEM medium supplemented with 14C-lysine and with 10 p. 100 hyperlipemic (type IV and V) or normal human serum respectively. The incubated fragments were extracted at increasing ionic strength. The insoluble collagen and elastin were hydrolysed with collagenase and alcoholic potassium hydroxyde respectively. The radioactivity was determined in the extracts and the radioactive labelling profile of proteins was investigated on polyacrylamide gel electrophoresis in SDS. With the exception of the collagenase extract (polymeric collagen) the incorporation of the radioactivity into insoluble collagen is not altered or increases. These the incubation was carried out in the presence of hyperlipemic serum. Incorporation of the radioactivity into insoluble collagen seems not to be altered. These results show a decreased protein synthesis with a relative increase in the biosynthesis of polymeric insoluble collagen in the aortic media incubated in the presence of hyperlipemic serum.

Adult↗
PubMed1978

[Ultrastructural organization of the basic substance of human dermis].

The data on ultrastructural organization of the ground substance in the human dermis obtained electron histochemically are represented. Five types of ruthenium positive structures of polysaccharide origin are detected: retinal structure (I), amorfous substance (II), membranes of collagen fibrils (III) and elastic fibres (V), fine ruthenium positive streakness of collagen fibrils (IV). These structures, except fine streakness, form a united polysaccharide system of the dermis participating in maintenance of structural-functional integrity of the connective tissue (collagen-elastic) carcass of the dermis. Two mechanisms, interconnected and oppositely directed, perform this function: the buffer mechanism preventing the connective tissue fibers and collagen fibrils to approach each other, and the binding mechanism preventing the fibrils and fibers to dissociate. The reticular structure performs mainly this function at the level of fibers, and the amorphous substance does it at the level of fibrils.

Collagen↗
PubMed1979

Characterization of dermal collagen in systemic sclerosis.

The amount of dermal collagen is increased in systemic sclerosis. However, unlike certain inflammatory conditions, the relative proportions of Type I and Type III collagens are closely similar to those found in normal adult dermis. Similarly, no change in the distribution of the collagen types could be detected by immunofluorescent staining, although a considerable thickening of the epidermis was clearly evident in all the sclerotic lesions examined.

Adult↗
PubMed2025

Rapidly decellularized adipose tissue induces soft tissue vascularization in potential anatomical spaces.

Decellularized tissues provide biological cues owing to the wealth of structural and regulatory factors that promote angiogenesis, adipogenesis, and myogenesis and facilitate neurite outgrowth. Here, we demonstrated the advantages of decellularized adipose tissue (adipoECM) over defined collagen-based biomaterials for host tissue integration. Three batches of human adipose tissue were decellularized using a rapid decellularization protocol and analyzed using mass spectrometry. To assess the biological activity of the decellularized materials, adipoECM and a reference standard of care biomaterial (Integra®DRT, also containing collagen I and glycosaminoglycans) were implanted subcutaneously, but far from the wound bed (in anatomical potential spaces) of immunocompetent BALB/c mice. The mice were euthanized in the acute (1 day) and chronic (day 60) inflammatory reaction phases, followed by biomaterial excision and Masson’s trichrome immunohistofluorescence imaging of the paraffin-embedded specimens. Each batch of processed tissue passed a quality control check, showing a low level of donor genomic DNA, lack of nuclei, lipids, endotoxins, and bacterial contamination. Mass spectrometry revealed that all batches of decellularized tissue mainly contained collagen I and, to a lesser degree, collagen III, collagen IV, collagen V, laminin, fibrillin, fibronectin, tenascin, and elastin. No acute inflammatory reaction was observed in either material one day post-transplantation. At 60 days post-implantation, different cell types were detected in adipoECM specimens, whereas Integra®DRT remained acellular. Additional immunohistochemical staining of adipoECM revealed CD31-positive cells in the blood vessels. Mesenchymal (CD90 positive) and myeloid (CD14 positive) cells were also detected. Primary cell types involved in soft tissue healing and remodeling were found in the adipoECM-treated group. The ingrowth of blood vessels and mesenchymal cells confirmed the effective integration of adipoECM with host tissues. Our results demonstrate that decellularized adipose tissue implanted away from the wound bed possesses contextual biological activities that promote efficient integration with host tissues.

Adipose Tissue↗
PubMed2026

Mesenchymal Stem Cell-Derived Exosomes Combined With 3-Dimensional Hyaluronan-Based Scaffold Promote Tendon-to-Bone Tunnel Healing.

PURPOSE: Tendon-to-bone healing remains a major clinical challenge due to poor regenerative capacity at the enthesis. This study aimed to evaluate the effects of mesenchymal stem cell-derived exosomes combined with a 3-dimensional hyaluronan-based scaffold on graft healing within bone tunnels. This study was conducted in accordance with the ARRIVE (Animal Research: Reporting of In Vivo Experiments) guidelines. METHODS: A total of 128 tendon-bone models were created in 64 Sprague-Dawley rats, randomized into four groups: control, exosome-only, scaffold-only, and exosome-loaded scaffold. At weeks 4 and 8 postoperatively, samples were analyzed histologically (hematoxylin-eosin, Masson Trichrome), immunohistochemically (fibroblast growth factor 2, bone morphogenetic protein 2), and biomechanically (maximum failure load). RESULTS: At both time points, the exosome-loaded scaffold group demonstrated significantly enhanced vascularization, cellular activity, and collagen fiber continuity and parallelism compared to all other groups (P < .05). Fibroblast growth factor 2 and bone morphogenetic protein 2 expression levels were highest in the exosome-loaded scaffold group, indicating early activation of proregenerative pathways. Biomechanically, this group also exhibited the greatest maximum failure load (15.64 &#xb1; 0.86 N at week 4; 22.97 &#xb1; 2.86 N at week 8), suggesting superior tendon-to-bone integration. The exosome-only group showed delayed but comparable improvements by week 8. CONCLUSIONS: Combining mesenchymal stem cell-derived exosomes with a 3-dimensional hyaluronan-based polycaprolactone/tricalcium phosphate scaffold enhances early and sustained healing at the tendon-bone interface. This cell-free, biocompatible strategy significantly improves vascularization, growth factor expression, collagen organization, and mechanical strength. These findings support its potential as a clinically translatable approach for improving tendon-to-bone healing outcomes. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic V.

Animals↗
PubMed1979

Altered collagen composition in a prolapsing mitral valve with ruptured chordae tendineae.

A patient presented with mitral valve prolapse, ruptured chordae tendineae, severe mitral regurgitation and congestive heart failure. Pathologic studies demonstrated myxomatous changes of both mitral leaflets. Collagen analysis of the valve and of the chordae tendineae revealed the presence of type I collagen in normal quantities and a striking absence of type III and AB collagens. The altered collagen in this patient's mitral valve probably contributed to the development of his mitral valve disorder.

Chordae Tendineae↗
PubMedDate not supplied

Activation of latent collagenase of human leukocytes and gingival fluid by bacterial plaque.

Collagenase activity was studied in human leukocytes, gingival crevicular fluid and bacterial plaque, with soluble radioactive collagen as substrate. Inflamed gingiva liberated vertebrate type collagenase into the crevicular fluid in active form. Healthy gingiva, in contrast, released collagenase in a latent form that could be activated by trypsin or plaque. Plaque also stimulated leukocytes to release collagenase, and activated the latent enzyme.

Bacteria↗
PubMed1977

[Hereditary deficiency in the enzymes of the biosynthesis of collagen. The Ehlers-Danlos syndromes (author's transl)].

The mechanism of the biosynthetic pathway of collagen is briefly summarised. The hereditary enzyme deficiencies of this pathway concern some of the Ehlers-Danlos syndromes. Seven clinically well defined varieties of these syndromes have been recognized, all presenting, as common feature, an hyperextensivitry of joints and hyperelastic, excessively fragile skin. In three of these seven varieties, the enzyme defect has been recently discovered: the type V (associated with chromosome X) is characterized by the deficiency in the lysyl-oxidase, the type VI (ocular) by the deficiency in lysyl-hydroylase; in the type VII (arthrolaxis multiplex congenita) the activity of tropocollagen-peptidase is practically absent. These enzyme deficiencies provide a molecular basis for the interpretation of the pathogenesis of these varieties of the Ehlers-Danlos syndrome.

Amino Acid Oxidoreductases↗
PubMed1977

1,25-dihydroxycholecalciferol and parathormone: effects on isolated osteoclast-like and osteoblast-like cells.

The actions of 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] and parathormone, both effective bone-resorptive agents in vivo and in vitro, were tested on CT (osteoclast-like) and PT (osteoblast-like) bone cells maintained in culture. Both agents stimulated acid phosphatase activity and hyaluronate synthesis in the CT cells and decreased alkaline phosphatase, citrate decarboxylation, and collagen synthesis in the PT cells. Calcitonin inhibited the changes induced in the CT but not in the PT cells. The activity of 1,25-(OH)2D3 differed from that of parathormone in one key respect: it did not increase cellular cyclic adenosine monophosphate, whereas parathormone did. Prior incubation of the bone cells with 1,25-(OH)2D3 for 6 to 24 hours made the cells refractory to the effect of parathormone on cyclic adenosine monophosphate formation. These data suggest that 1,25-(OH)2D3 and parathormone induce bone resorption by affecting the same cell types (osteoblasts and osteoclasts) although at different cellular sites.

Acid Phosphatase↗
PubMed1976

Characterization of the collagen synthesized by endothelial cells in culture.

[14C]Proline and [14C]lysine were incorporated into collagen by cultures of endothelial cells derived from calf aortae. The isomer 3-hydroxy[14C]proline accounted for 10% of the total hydroxy[14C]proline in the collagen isolated from the medium. Approximately 81% of the hydroxy[14C]lysine isolated from the medium was glycosylated, and 91% of the glycosylated hydroxy[14C]lysine was in the form of the disaccharide glucosylgalactose. Gel filtration chromatography or acrylamide gel electrophoresis in the presence of sodium dodecyl sulfate indicated that the initially synthesized peptide chain of [14C]collagen had a molecular weight of about 135,000; after pepsin digestion this was converted to 115,000. The ratio of hydroxy[14C]proline to total [14C]proline x 100 in the pesin-resistant fraction was 59. When examined by immunofluorescence microscopy, the endothelial cultures stained positively with antiserum to (Type IV) collagen from basement membrane of bovine anterior lens capsule. The data indicate that cultured endothelial cells derived from calf aortae synthesize collagen that resembles that of basement membrane collagen.

Aorta↗
PubMed1975

Studies on hyaluronic acid. V. Relationship between the protein content and viscosity of rooster comb dermis hyaluronic acid.

Protein accounted for an average of 8.7% w/w of the hyaluronic acid obtained from rooster comb dermis extracts and three types of peptide constituents appeared to be present. A few collagen-like fibers were closely associated with the hyaluronic acid when samples were examined in the electron microscope and collagenase treatment decreased the intrinsic viscosity from 7000-5000 ml/g to 3900-2700 ml/g. The quantities of collagen present, however, were too small to detect chemically with the methods employed. The major peptide consituent was readily separated from the hyaluronic acid by fractionation in a cesium chloride gradient or by treatment with pronase. The viscosity was decreased by the density gradient procedure but not by the pronase digestion. Repeated fractionation in a cesium chloride gradient decreased the intrinsic viscosity still further and a small peptide constituent with a high glycine and serine content remained associated with a hyaluronic acid. The data suggest that an interaction or entanglement with collagen fibers is responsible for the high viscosity of hyaluronic acid in this tissue extract and that the viscosity of purified hyaluronic acid preparations is dependent upon interactions between adjacent polysaccharide chains. Interactions between the major peptide constituent and polysaccharide chains or the small residual peptide component remaining with hyaluronic acid after extensive purification procedures, however, appear to be involved in some organized structure because the presence of the major peptide constituent minimized the decrease in viscosity that occurred when hyaluronic acid samples were lyophilized.

Amino Acids↗
PubMed1979

Ultrastructural aspects of normolipidemic xanthomatosis.

Electron microscopic aspects in ten cases of normolipidemic cutaneous xanthomatosis have been investigated. Two additional types IV and V hyperlipoproteinaemic xanthomatosis have also been included. Ultrastructural findings in all cases were similar. Abundant histiocytic cells with numerous intracytoplasmic lipid vacuoles, lysosomes, and myelin-figures, were the striking features. Moreover, in older lesions microfilaments and lipid vacuoles were found in some fibroblastic cells, as well as long space collagen around them. In some specimens we observed: giant multinucleated histiocytic cells, crystalline cleft-like spaces in histiocytes and some mastocytes with lipidic crystals in the extracellular space, as well as lipid vacuoles in Schwann cells, endothelial cells and pericytes. Rod-shaped tubulated bodies were found in some endothelial cells, with multiple basal vascular laminae. In xantelasma palpebrarum and in disseminate plane xanthoma the histiocytary foamy cells adopted a perivascular arrangement, as in hyperlipoproteinemic xanthomatosis. We concluded that ultrastructural aspects of different xanthomatosis are fairly similar as a consequence of the large amount of intracytoplasmic lipids accumulated in xanthomatosus cells. In xanthelasma palpebrarum and in disseminated plane xanthoma this cell phase is reached by similar pathways to those for hyperlipoproteinemic xanthomatosis, whilst in xanthoma disseminatum and juvenile xanthogranuloma the pathways seem to be different. A classification of normolipidemic xanthomatosis is also provided.

Histiocytes↗
PubMed1976

Pepsin-solubilized collagen of human nucleus pulposus and annulus fibrosus.

Human nucleus pulposus and annulus fibrosus, obtained at autopsy from patients 7-30 years of age, were extracted with 2 M guanidine-HCl (pH 5.82) to remove proteoglycans, then stirred with pepsin in 0.5 M acetic acid, followed by three 24-h extractions with 1 M NaCl (pH 7.5) and one 24-h extraction with 2 M KSCN (potassium thiocyanate) (pH 7.2). Pepsin and NaCl solubilized an average of about 30% of nucleus pulposus collagen and 18% of annulus fibrosus collagen. KSCN extracted a further 34% of nucleus pulposus collagen and only 4% of annulus fibrosus collagen. CM-cellulose chromatography of nucleus and annulus collagen purified from the pepsin, NaCl and KSCN supernatants consistently revealed only one peak, always appearing slightly ahead of the alpha1 position for rat tail tendon type I collagen. Polyacrylamide and SDS-gel electrophoresis consistently revealed only one band with the mobility of alpha1 chains. Amino acid composition of collagen from nucleus and annulus is comparable to those of mammalian and avian cartilage type II collagen, and distinctly different from those of rat tail tendonand guinea pig skin type I collagens. Periodate oxidation of nucleus and annulus collagens showed that 81% and 67%, respectively, of the hydroxylysine residues survive treatment, compared to 71% for bovine articular cartilage collagen and 17% for guinea pig skin collagen. Total hexose analysis revealed 1.8 muM and 2.0 muM hexose per muM periodate-stable hydroxylysine in nucleus and annulus collagens, respectively. Ion exchange chromatography showed the presence of glucose and galactose in a ratio of 0.92:1 in nucleas collagen and 1.07:1 in annulus collagen. Pepsin-solubilized, NaCl-extracted collagen from nucleus and annulus formed native-type fibrils in vitro. The banding patterns of ATP-induced segment-long-spacing precipitates of nucleus and annulus collagens were identical to each other and indistinguishable from those of cartilage (type II) collagen, but distinctly different from those of rat tail tendon (type I) collagen. These data suggest that the collagen which can be extracted after limited pepsin attack of human nucleus and annulus is of the form [alpha1 (II)]3.

Adolescent↗
PubMed1978

[Regional features of the architectonics of the dermal fibrous framework of human skin].

Collagenous carcass of human derma is formed by interconnected fibrils, fibrillar fasciculi, fibers and their fasciculi. The latter form a three-dimentional network or spatial carcass (collagenous dermal pattern) subdivided into three main types (layer-forming, rhombic and complex-looped) and several mixed types of pattern. Every pattern has its own definite topographic-anatomical localization in the human body, depends on the functional loading experienced by every part of the body and is historically connected with the erect posture and labour activity.

Biomechanical Phenomena↗
PubMed1977

Experimental vitreous haemorrhage: echographic appearances.

Vitreous haemorrhages were induced in rabbits and the echographic appearances of A and B scan were correlated with the gross and histologic appearances over a period of twenty weeks. In all cases, visible vitreous opacities produced distinct echo patterns. As the haemorrhages cleared, the echo amplitudes became progressively weaker. Several patterns of vitreous "membranes" on B scan were also observed. Pathological examination revealed that such membranes were composed of red cells, macrophages and condensed vitreous collagen. It is suggested that haematogenous vitreous membranes of this type are readily diagnosed by combined A- and B-scan ultrasonic examination, and are probably amenable to surgery.

Eye Diseases↗
PubMed1978

Antibodies to type II collagen in relapsing polychondritis.

Relapsing polychondritis is a disorder of unknown cause characterized by the destruction of cartilage. To test the hypothesis that immunologic mechanisms are involved in the pathogenesis of relapsing polychondritis, we analyzed the serum of 15 patients for the presence of antibodies to cartilage. Antibodies to Type II (cartilage) collagen were found in the serum of five patients at the time of acute symptoms. No antibodies were detected either to cartilage proteoglycan or to other collagen types. The antibodies were detected at the onset of the disease and their titers appeared to correlate with severity of disease. Circulating immune complexes were also detected in the serum of these patients. Our findings support an immunologic involvement in this condition.

Acute Disease↗
PubMedDate not supplied

Platelet coagulant activities in arterial occlusive disease of the eye.

Ischemic optic neuropathy and retinal arterial occlusion are 2 forms of arterial occlusive disease affecting the eye. Reports in the literature suggest platelet hyperactivity in acute arterial occlusive diseases affecting other organ systems. Therefore, 14 patients with ischemic optic neuropathy and 17 patients with central or branch retinal artery occlusion were studied to determine whether platelets have a role in the pathogenesis of these vascular occlusive disorders. The results of the following investigations were no different in these patients compared with those in 18 control patients with non-vascular eye diseases: prothrombin times, partial thromboplastin times, plasma fibrinogen, factor V, factor VIII, platelet counts and threshold concentrations of ADP, epinephrine and collagen resulting in secondary platelet aggregation and serotonin release. In contrast, platelet coagulant activities concerned with the early stages of intrinsic coagulation were significantly increased in patients with retinal artery occlusion without hypertension or type IV hyperlipoproteinemia, but generally normal in patients with ischemic optic neuropathy and in patients with retinal artery occlusion associated with hypertension, type IV hyperlipoproteinemia, diabetes mellitus and generalized atherosclerosis. These results are consistent with a platelet contribution to retinal arterial occlusive disease in patients without other known contributing factors such as hypertension, serum lipid abnormalities, diabetes mellitus and generalized atherosclerosis and may have implications regarding prophylaxis.

Adult↗