Production of Hyaluronate and Collagen by Fibroblast Clones in Culture

Tendon Extracellular Matrix Assembly, Maintenance and Dysregulation Throughout Life

In his Lissner Award medal lecture in 2000, Stephen Cowin asked the question: "How is a tissue built?" It is not a new question, but it remains as relevant today as it did when it was asked 20 years ago. In fact, research on the organization and development of tissue structure has been a primary focus of tendon and ligament research for over two centuries. The tendon extracellular matrix (ECM) is critical to overall tissue function; it gives the tissue its unique mechanical properties, exhibiting complex non-linear responses, viscoelasticity and flow mechanisms, excellent energy storage and fatigue resistance. This matrix also creates a unique microenvironment for resident cells, allowing cells to maintain their phenotype and translate mechanical and chemical signals into biological responses. Importantly, this architecture is constantly remodeled by local cell populations in response to changing biochemical (systemic and local disease or injury) and mechanical (exercise, disuse, and overuse) stimuli. Here, we review the current understanding of matrix remodeling throughout life, focusing on formation and assembly during the postnatal period, maintenance and homeostasis during adulthood, and changes to homeostasis in natural aging. We also discuss advances in model systems and novel tools for studying collagen and non-collagenous matrix remodeling throughout life, and finally conclude by identifying key questions that have yet to be answered.

Activity and Effectiveness of Recombinant hEGF Excreted by Escherichia coli BL21 on Wound Healing in Induced Diabetic Mice

Context

Human epidermal growth factor (hEGF) has biological activities and can be used in medicines and cosmetics. A high level of effectiveness of hEGF can be obtained when three disulfide bonds fold perfectly. Extracellular secretion from E. coli BL21 using the PelB signal peptide is a new way to obtain hEGF with a structure that folds appropriately.

Object

This study aimed to determine the activity and effectiveness of recombinant hEGF excreted by E. coli BL21 on wound healing in induced diabetic mice.

Methods

Cell proliferation and migration tests were performed on NIH3T3 cells, followed by wound healing tests in induced diabetic mice, along with histological and endotoxin test at various hEGF concentrations (25, 50, and 75 µg/mL).

Results

Based on the results, hEGF at a level of 50 μg/mL showed optimal proliferation and migration activities. Wound healing in induced diabetic mice showed faster-wound closure within 12 days at hEGF 50 and 75 µg/mL with a percentage wound closure of 95% and 98.5%, respectively, which was significant versus control. In the histology test, the number of fibroblasts showed an increase and was significant at hEGF 75 µg/mL compared to the control group. The single test vial (STV) showed that hEGF solution was free of endotoxin.

Conclusion

Recombinant hEGF produced by extracellular secretion using E. coli BL21 has optimal diabetic wound healing activity through increased fibroblast proliferation.

Kinetic analysis of experimental post-operative peritoneal healing: the incorporation of proline and glucosamine by exudative and tissue repair cells

The purpose of this study was to experimentally investigate the cellular composition of post-surgical peritoneal fluid and peritoneal tissue and determine the patterns of 14C-proline and 14C-glucosamine incorporation by the peritoneal exudative cells and peritoneal tissue repair cells (PEC and PTRC). One group of rabbits underwent resection (2.0 cm) and reanastomosis of their ileum, and another group underwent peritoneal wall abrasion. Postoperatively (1-28 days), the PEC and PTRC were collected and incubated for 5 days with 0.5 mu Ci 14C-glucosamine or 14C-proline, and the specific activity thereafter determined by beta counting. On the 1st postoperative day, the total cell number (TCN) has increased (7.7 x 10(7) cells/rabbit) to 770 per cent of the control values primarily as a result of the PMN influx (89.9 per cent). On day 3, the TCN was 6.1 x 10(7), 58.5 per cent of which comprised macrophages, which had become the principle cell type by day 5. The incorporation of proline and glucosamine into the PEC increased significantly peaking on day 7 then decreasing to the control value by day 21. Proline incorporation into the PTRC increased significantly, reaching a peak value on day 5, which decreased by day 10. Glucosamine incorporation reached a peak value on day 7 then decreased by day 10. In conclusion, the increase in glucosamine and proline incorporation into the PTRC parallels the increase in PEC, comprised principally of macrophages. These findings suggest that analysis of the metabolic activities in peritoneal activated macrophages may provide a useful tool to dissect the central mediation of postsurgical peritoneal re-epithelialization.

Modulation of proline and glucosamine incorporation into tissue repair cells by peritoneal macrophages

The purpose of this study was to determine the patterns of [14C]proline and [14C]glucosamine incorporation by tissue repair cells (TRC) as modulated by postsurgical macrophages. Rabbits underwent a midline laparotomy followed by resection (2.0 cm) and reanastomosis of their ileum. Another group of rabbits underwent peritoneal wall abrasion with sterile gauze until punctate bleeding developed. Postoperative (1-28 days) exudate cells (PEC) were recovered from the peritoneal cavity after reanastomosis, and (TRC) were obtained directly from the injured peritoneal surface after abrasion. Since the postsurgical exudate was composed mainly of macrophages, we examined the effect of postsurgical macrophage-spent media on the incorporation of [14C]proline, [14C]glucosamine, and [3H]thymidine by TRC. After 7 days of culture, Postsurgical Day 7 TRC were incubated with spent media from postsurgical PEC (greater than 90% macrophages). When TRC were cultured with macrophage-spent media, the number of TRC increased significantly compared to that of fresh medium-treated controls. The incorporation of [3H]thymidine by TRC was also enhanced by macrophage-spent media. The incorporation of [14C]proline and [14C]glucosamine by TRC was also enhanced when incubated with macrophage-spent medium. However, when data were expressed on a per cell basis, incorporation of [14C]proline and [14C]glucosamine by TRC cultured with macrophage-spent media was the same or less than that by cells incubated with fresh medium. These data suggest that the increase in incorporation of glucosamine and proline into connective tissue protein by postsurgical repair cells may be directly modulated by macrophages recruited in response to surgical injury and that this increase is due to the fibroproliferative effect of postsurgical macrophages.

Developmental pattern of cAMP, adenyl cyclase, and cAMP phosphodiesterase in the palate, lung, and liver of the fetal mouse: alterations resulting from exposure to methylmercury at levels inhibiting palate closure

Exposure to methylmercury (MeHg: 10 mg Hg/kg maternal body weight) on 12(6) (days hours) of gestation significantly delays palate closure in the Swiss Webster CFW mouse. The cAMP content and activity of adenyl cyclase and phosphodiesterase (PDE) were measured in the tissues of control and MeHg-induced cleft palates between 13(6) and 17(6) of gestation. Lung and liver were investigated similarly to determine if MeHg affected the adenyl cyclase system of the palate in a unique manner. In control palatal tissue, cAMP levels increased sharply from 13(22) (undetectable) to 14(6) (maximum). PDE activity increased similarly up to 14(2), but decreased 50% between 14(2) and 14(6). Since it has been reported that cAMP induces the synthesis of PDE, the difference in cAMP/PDE from 13(22) to 14(2) and from 14(2) to 14(6) suggests the localization of relatively high levels of cAMP in at least two separate compartments. Between 14(6) and 14(10), the adenyl cyclase activity of control palates decreased significantly. This rapid decrease suggests relatively high adenyl cyclase activity in the medial edge epithelial cells which undergo autolysis prior to shelf fusion (centered at 14(15). Maternal MeHg administration at 12(6) delayed the median time of palatal shelf rotation (14(13)) by 5 hours, and significantly altered the developmental pattern of the adenyl cyclase system. Thus, the increase in cAMP between 14(2) and 14(6) was abolished and the decrease in adenyl cyclase activity between 14(6) and 14(10) was delayed by almost 20 hours. These changes may be manifestions of a MeHg-induced delay in medial edge epithelial cell differentiation. In a previous study, we observed that the fetal liver exhibits the highest MeHg concentration of all tissues. Since MeHg only slightly altered the adenyl cyclase system of the fetal liver compared to the lung and palate (in which MeHg uptake is considerably less), it may be that the effects of MeHg on palatal tissue are not due to a direct effect of MeHg on components of the adenyl cyclase system.

A human liposarcoma cell line producing hyaluronic acid

A human liposarcoma cell line COLO 222, derived from a primary tumor in a 62-year-old male, elaborates hyaluronic acid. COLO 222 is characterized on the basis of histochemical, ultramorphological, and cytogenetic properties, along with isozyme phenotype and cell products. A chromosome mode of 53 predominates and unique Giemsa-banded marker chromosomes are identified. An autochthonous lymphoid cell line, COLO 143v, was established after the addition of exogenous Epstein-Barr virus. Cytogenetic analysis of Colo 143v is consistent with a normal male karyotype. COLO 143v possesses B-cell characteristics. This autochthonous system had been used for immunological studies and cytotoxicity assays.

Cellular differentiation and the aging process in cartilaginous tissues. Mucopolysaccharide synthesis in cell cultures of chondrocytes

Primary cell cultures of differentiated chondrocytes were shown to produce chondroitin-4-sulfate as the predominant mucopolysaccharide, with suggestive evidence for the synthesis of keratan sulfate and possibly chondroitin-6-sulfate. Chicken embryonic cartilage was shown to be composed mainly of chondroitin-4-sulfate, with a small amount of chondroitin-6-sulfate, but essentially no keratan sulfate. These findings were compared to the data of others, and a hypothesis explaining the aging process in cartilage in terms of cellular differentiation was presented.

Chemical and histochemical characterization of mucopolysaccharides in a jaw myxoma

Chemical and histochemical analyses, including testicular and staphylococcal hyaluronidase digestion, have been made of a jaw myxoma and the results show the presence of two acid mucopolysaccharides. Of the total mucopolysaccharide present 80% was hyaluronic acid and 20% chondroitin sulphate. The high content of non-sulphated mucopolysaccharide would seem to explain the paucity of fibres characteristic of the myxoma. It is suggested that myxomas generally probably have a similar high hyaluronic acid content. It is considered that the cell concerned is a mesenchymal cell elaborating non-sulphated mucopolysaccharide and may be called a ;myxoblast'; it is metabolically different from the sulphated-mucopolysaccharide-collagen-producing fibroblast. The high hyaluronic acid content is much greater than that found in embryonic connective tissue and may be a significant factor in the neoplastic behaviour of the myxomatous tissue. The aggressive behaviour of the myxoma is against a simple reversion to embryonic mesenchyme. It is concluded that the myxoblast is an active mucopolysaccharide-secreting cell and that mucin in the myxoma is not a sign of cell degeneration of preexisting fibroblasts or collagen.

Ascorbic acid deficiency in cultured human fibroblasts

Fibroblasts grown in medium containing less than 1 microg of ascorbic acid per milliliter showed evidence of ascorbic acid deficiency when compared with cells grown in medium containing 50 microg of ascorbic acid per milliliter. This was manifested morphologically by dilated endoplasmic reticulum, a decrease in number, size, and intensity of staining of the mitochondria, by defective intercellular fibril formation, and by easy disaggregation of the cells from the intercellular matrix after treatment with pronase. When 50 microg per milliliter of ascorbic acid was incorporated into the medium, the altered morphology was corrected, banded fibrils were produced which were organized into bundles, and the cells were tightly bound in a matrix which was resistant to disaggregation with a variety of proteolytic enzymes. Collagen and sulfated glycosaminoglycan synthesis were less in the control than in the ascorbic acid supplemented cells. Similar morphological and chemical changes have been reported in the connective tissue of scorbutic animals. The effects of low ascorbic acid concentration on fibroblasts in culture indicate that these cells require ascorbic acid to maintain connective tissue functions.