The effect of human dental plaque on bone resorption and hyaluronic acid synthesis in in-vitro cultures of fetal rat calvaria

Ammonium chloride, a known inhibitor of lysosomal function, was found to be a rapid and potent inhibitor of 45Ca release from fetal rat bones in organ culture. The response to parathyroid hormone and prostaglandin E2 was inhibited in a dose-related, reversible fashion. The activity of the lysosomal enzyme beta-glucuronidase in the medium closely paralleled 45Ca release. Ammonium chloride may now be added to the list of antilysosomal agents that inhibit bone resorption in vitro.

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In vitro synthesis of glycosaminoglycans in endocrine ophthalmopathy

Acta Endocrinologica ◽

10.1530/acta.0.1270397 ◽

1992 ◽

Vol 127 (5) ◽

pp. 397-402 ◽

Cited By ~ 6

Author(s):

G Kahaly ◽

C Stover ◽

J Beyer ◽

E Otto

Keyword(s):

Hyaluronic Acid ◽

Acid Concentration ◽

Cetylpyridinium Chloride ◽

Acid Synthesis ◽

Cell Mediated Immunity ◽

Glycosaminoglycan Synthesis ◽

In Vitro Synthesis ◽

Significant Difference ◽

Endocrine Ophthalmopathy

The effects of humoral and cell-mediated immunity on the glycosaminoglycan synthesis of retrobulbar fibroblasts was evaluated in patients with endocrine ophthalmopathy. After incubation with IgG and sera, secreted glycosaminoglycans, radiolabeled with D-6-3H-glucosamine and 35sulfate, were precipitated with cetylpyridinium chloride and ethanol. Hyaluronic acid synthesis of human retrobulbar fibroblasts after incubation with sera and IgG and after co-culture with lymphocytes was assessed by means of a radiometric test. Patients' IgG, compared to controls', accounted for a higher secretory stimulation of porcine retrobulbar fibroblasts (as measured by cetylpyridinium chloride precipitation) after 24 and 48 h. Contrasting with 24 h incubation time, glycosaminoglycan values after 48 h were increased two to threefold. Patients' and controls' sera caused earlier and stronger, yet indistinguishable glycosaminoglycan production. Non-sulfated hyaluronic acid was the preponderant glycosaminoglycan secreted into the media by retrobulbar fibroblasts. As assessed with the radiometric test, incubation with patients' and controls' sera and IgG did not reveal a significant difference in stimulating the hyaluronic synthesis of patients' and controls' retrobulbar fibroblasts. When measuring the hyaluronic acid synthesis of controls' and patients' retrobulbar fibroblasts after co-cultivation of lymphocytes, however, patients' lymphocytes had a marked ability to increase the hyaluronic acid concentration compared to controls' lymphocytes. The hyaluronic acid concentration after incubation of a patient's retrobulbar fibroblasts with autologous lymphocytes was markedly more elevated than the intrinsic hyaluronic acid production of retrobulbar fibroblasts. In conclusion, though a significant in vitro influence of patients' IgG and sera on the glycosaminoglycan release of both porcine and human (patients' as well as controls') retrobulbar fibroblasts could not be observed in this study, the indications of a marked stimulatory influence of lymphocytes on the hyaluronic acid secretion of retrobulbar fibroblasts demand further investigation.

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Effects of prostaglandin E2 and dental plaque on bone collagen and hyaluronic acid synthesis

American Journal of Orthodontics ◽

10.1016/0002-9416(86)90021-7 ◽

1986 ◽

Vol 89 (6) ◽

pp. 527

Author(s):

Tom Zwemer

Keyword(s):

Hyaluronic Acid ◽

Prostaglandin E2 ◽

Dental Plaque ◽

Acid Synthesis ◽

Bone Collagen

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Physiological concentrations of retinoic acid suppress the osteoblastic differentiation of fetal rat calvaria cells in vitro

Acta Endocrinologica ◽

10.1530/eje.0.1330335 ◽

1995 ◽

Vol 133 (3) ◽

pp. 335-341 ◽

Cited By ~ 26

Author(s):

Keiji Ohishi ◽

Seiji Nishikawa ◽

Toshihiko Nagata ◽

Noriyuki Yamauchi ◽

Hiroyuki Shinohara ◽

...

Keyword(s):

Retinoic Acid ◽

High Performance ◽

Osteoblastic Differentiation ◽

Dependent Manner ◽

High Concentration ◽

Physiological Concentration ◽

Rat Calvaria ◽

Fetal Rat ◽

School Of Dentistry

Ohishi K, Nishikawa S, Nagata T, Yamauchi N, Shinohara H, Kido J, Ishida H. Physiological concentrations of retinoic acid suppress the osteoblastic differentiation of fetal rat calvaria cells in vitro. Eur J Endocrinol 1995;133:335–41. ISSN 0804–4643 The effects of retinoic acid (RA) on osteoblastic differentiation and activity were studied in fetal rat calvaria cells cultured for up to 24 days. Fetal bovine serum used for the experiments was treated with an anion-exchange resin to remove endogenous RA. The depletion of RA in the treated serum was confirmed by high-performance liquid chromatography and tritiated RA tracing. Under the culture conditions employed, the continuous presence of RA for 14 days at 10−9 mol/l or higher decreased both alkaline phosphatase (ALP) activity on day 12 and the number of bone nodules on day 14 in a dose-dependent manner. Short-term (24 h) exposure to RA at 10−8 mol/l, which is a physiological concentration, decreased and increased the levels of ALP and osteopontin mRNA on day 6, respectively. Retinoic acid at 10−8 mol/l also increased the level of osteocalcin mRNA on day 12. However, these effects were not obvious at later stages (days 18 and 24). At a high concentration (10−6 mol/l). RA increased the level of osteopontin mRNA on day 6 and decreased the levels of ALP and osteocalcin mRNA irrespective of culture period. These results suggest that, at physiological concentrations, RA suppresses the differentiation of osteoprogenitor cells and regulates osteoblastic functions. H Ishida, Department of Periodontology and Endodontology. Tokushima University School of Dentistry, 3-18-15 Kuramoto-cho, Tokushima 770, Japan

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Effects of forskolin on bone in organ culture

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1987.252.1.e44 ◽

1987 ◽

Vol 252 (1) ◽

pp. E44-E48

Author(s):

N. S. Krieger ◽

P. H. Stern

Keyword(s):

Parathyroid Hormone ◽

Bone Resorption ◽

Calcium Release ◽

Dependent Manner ◽

Bone Culture ◽

Length Of Treatment ◽

Fetal Rat ◽

Neonatal Mouse Calvaria ◽

Dose Dependent

The effects of forskolin, which directly activates adenylate cyclase in most systems, have been compared with the actions of parathyroid hormone and calcitonin, both of which have been suggested to utilize cAMP as a second messenger in their actions on bone. Forskolin alone stimulated calcium release from neonatal mouse calvaria and fetal rat limb bones in vitro in a dose-dependent manner. The effect was maximal at 10(-6) M in both systems. At higher concentrations forskolin completely inhibited stimulated bone resorption, although with submaximal concentrations the inhibition was only partially sustained up to 72 h. Forskolin directly stimulated cAMP release from calvaria into the medium at concentrations up to 10(-4) M. Forskolin had no effect on the interaction between parathyroid hormone and calcitonin, while calcitonin inhibited the stimulatory effect of forskolin comparably with its inhibition of parathyroid hormone-stimulated bone resorption. The results indicate that forskolin has dual effects on bone and can mimic responses of both parathyroid hormone and calcitonin in both bone culture systems. The observed response depends on the concentration of forskolin used and the length of treatment with the drug.

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