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Chondroitin and glucosamine sulfate in combination decrease the pro-resorptive properties of human osteoarthritis subchondral bone osteoblasts: a basic science study.

Tat SK, Pelletier JP, Vergés J, Lajeunesse D, Montell E, Fahmi H, Lavigne M, Martel-Pelletier J - Arthritis Res. Ther. (2007)

Bottom Line: Under basal conditions, RANKL expression was significantly reduced by CS and by both drugs incubated together.Under vitamin D3, these drugs also showed a decrease in RANKL level, which, however, did not reach statistical significance.This was confirmed by the decreased resorptive activity for the combination of CS and GS.

View Article: PubMed Central - HTML - PubMed

Affiliation: Osteoarthritis Research Unit, University of Montreal Hospital Centre, Notre-Dame Hospital, 1560 rue Sherbrooke Est, Montreal, Quebec H2L 4M1, Canada. kwantats@yahoo.fr

ABSTRACT
Early in the pathological process of osteoarthritis (OA), subchondral bone remodelling, which is related to altered osteoblast metabolism, takes place. In the present study, we explored in human OA subchondral bone whether chondroitin sulfate (CS), glucosamine sulfate (GS), or both together affect the major bone biomarkers, osteoprotegerin (OPG), receptor activator of nuclear factor-kappa B ligand (RANKL), and the pro-resorptive activity of OA osteoblasts. The effect of CS (200 mug/mL), GS (50 and 200 mug/mL), or both together on human OA subchondral bone osteoblasts, in the presence or absence of 1,25(OH)2D3 (vitamin D3) (50 nM), was determined on the bone biomarkers alkaline phosphatase and osteocalcin, on the expression (mRNA) and production (enzyme-linked immunosorbent assay) of bone remodelling factors OPG and RANKL, and on the pro-resorptive activity of these cells. For the latter experiments, human OA osteoblasts were incubated with differentiated peripheral blood mononuclear cells on a sub-micron synthetic calcium phosphate thin film. Data showed that CS and GS affected neither basal nor vitamin D3-induced alkaline phosphatase or osteocalcin release. Interestingly, OPG expression and production under basal conditions or vitamin D3 treatment were upregulated by CS and by both CS and GS incubated together. Under basal conditions, RANKL expression was significantly reduced by CS and by both drugs incubated together. Under vitamin D3, these drugs also showed a decrease in RANKL level, which, however, did not reach statistical significance. Importantly, under basal conditions, CS and both compounds combined significantly upregulated the expression ratio of OPG/RANKL. Vitamin D3 decreased this ratio, and GS further decreased it. Both drugs reduced the resorption activity, and statistical significance was reached for GS and when CS and GS were incubated together. Our data indicate that CS and GS do not overly affect cell integrity or bone biomarkers. Yet CS and both compounds together increase the expression ratio of OPG/RANKL, suggesting a positive effect on OA subchondral bone structural changes. This was confirmed by the decreased resorptive activity for the combination of CS and GS. These data are of major significance and may help to explain how these two drugs exert a positive effect on OA pathophysiology.

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Levels of alkaline phosphatase and osteocalcin in human osteoarthritis subchondral bone osteoblasts. Alkaline phosphatase activity (a) and osteocalcin level (b) were determined after treatment with chondroitin sulfate (CS) (200 μg/mL), glucosamine sulfate (GS) (50 or 200 μg/mL), or both (200 μg/mL each) in the absence or presence of vitamin D3 at 50 nM. Alkaline phosphatase activity (a) was determined in the cell lysate by substrate hydrolysis using p-nitrophenylphosphate, whereas osteocalcin level (b) was determined in the culture media by using a specific enzyme immunoassay. Data are from eight independent experiments. Statistical significance was assessed by paired Student t test. P value indicates the statistical difference between control (C, basal conditions) and vitamin D3-treated specimens.
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Figure 1: Levels of alkaline phosphatase and osteocalcin in human osteoarthritis subchondral bone osteoblasts. Alkaline phosphatase activity (a) and osteocalcin level (b) were determined after treatment with chondroitin sulfate (CS) (200 μg/mL), glucosamine sulfate (GS) (50 or 200 μg/mL), or both (200 μg/mL each) in the absence or presence of vitamin D3 at 50 nM. Alkaline phosphatase activity (a) was determined in the cell lysate by substrate hydrolysis using p-nitrophenylphosphate, whereas osteocalcin level (b) was determined in the culture media by using a specific enzyme immunoassay. Data are from eight independent experiments. Statistical significance was assessed by paired Student t test. P value indicates the statistical difference between control (C, basal conditions) and vitamin D3-treated specimens.

Mentions: Previous studies with human OA subchondral osteoblasts have shown that these cells have abnormal bone biomarker levels [12,13,16,17](In this study, we first looked at two such biomarkers, namely alkaline phosphatase and osteocalcin. Data showed (Figure 1a,b) that alkaline phosphatase activity and osteocalcin responded to vitamin D3, as is expected from human subchondral bone osteoblasts, with approximately 1.5- and 8-fold increases for alkaline phosphatase and osteocalcin, respectively, over basal values. Neither alkaline phosphatase nor osteocalcin was truly affected by CS or GS alone or together; this is true for both basal conditions and hormonal stimulation. There was a tendency for all treated specimens to show higher levels of vitamin D3-induced osteocalcin release, yet this failed to reach statistical significance (Figure 1b).


Chondroitin and glucosamine sulfate in combination decrease the pro-resorptive properties of human osteoarthritis subchondral bone osteoblasts: a basic science study.

Tat SK, Pelletier JP, Vergés J, Lajeunesse D, Montell E, Fahmi H, Lavigne M, Martel-Pelletier J - Arthritis Res. Ther. (2007)

Levels of alkaline phosphatase and osteocalcin in human osteoarthritis subchondral bone osteoblasts. Alkaline phosphatase activity (a) and osteocalcin level (b) were determined after treatment with chondroitin sulfate (CS) (200 μg/mL), glucosamine sulfate (GS) (50 or 200 μg/mL), or both (200 μg/mL each) in the absence or presence of vitamin D3 at 50 nM. Alkaline phosphatase activity (a) was determined in the cell lysate by substrate hydrolysis using p-nitrophenylphosphate, whereas osteocalcin level (b) was determined in the culture media by using a specific enzyme immunoassay. Data are from eight independent experiments. Statistical significance was assessed by paired Student t test. P value indicates the statistical difference between control (C, basal conditions) and vitamin D3-treated specimens.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2246236&req=5

Figure 1: Levels of alkaline phosphatase and osteocalcin in human osteoarthritis subchondral bone osteoblasts. Alkaline phosphatase activity (a) and osteocalcin level (b) were determined after treatment with chondroitin sulfate (CS) (200 μg/mL), glucosamine sulfate (GS) (50 or 200 μg/mL), or both (200 μg/mL each) in the absence or presence of vitamin D3 at 50 nM. Alkaline phosphatase activity (a) was determined in the cell lysate by substrate hydrolysis using p-nitrophenylphosphate, whereas osteocalcin level (b) was determined in the culture media by using a specific enzyme immunoassay. Data are from eight independent experiments. Statistical significance was assessed by paired Student t test. P value indicates the statistical difference between control (C, basal conditions) and vitamin D3-treated specimens.
Mentions: Previous studies with human OA subchondral osteoblasts have shown that these cells have abnormal bone biomarker levels [12,13,16,17](In this study, we first looked at two such biomarkers, namely alkaline phosphatase and osteocalcin. Data showed (Figure 1a,b) that alkaline phosphatase activity and osteocalcin responded to vitamin D3, as is expected from human subchondral bone osteoblasts, with approximately 1.5- and 8-fold increases for alkaline phosphatase and osteocalcin, respectively, over basal values. Neither alkaline phosphatase nor osteocalcin was truly affected by CS or GS alone or together; this is true for both basal conditions and hormonal stimulation. There was a tendency for all treated specimens to show higher levels of vitamin D3-induced osteocalcin release, yet this failed to reach statistical significance (Figure 1b).

Bottom Line: Under basal conditions, RANKL expression was significantly reduced by CS and by both drugs incubated together.Under vitamin D3, these drugs also showed a decrease in RANKL level, which, however, did not reach statistical significance.This was confirmed by the decreased resorptive activity for the combination of CS and GS.

View Article: PubMed Central - HTML - PubMed

Affiliation: Osteoarthritis Research Unit, University of Montreal Hospital Centre, Notre-Dame Hospital, 1560 rue Sherbrooke Est, Montreal, Quebec H2L 4M1, Canada. kwantats@yahoo.fr

ABSTRACT
Early in the pathological process of osteoarthritis (OA), subchondral bone remodelling, which is related to altered osteoblast metabolism, takes place. In the present study, we explored in human OA subchondral bone whether chondroitin sulfate (CS), glucosamine sulfate (GS), or both together affect the major bone biomarkers, osteoprotegerin (OPG), receptor activator of nuclear factor-kappa B ligand (RANKL), and the pro-resorptive activity of OA osteoblasts. The effect of CS (200 mug/mL), GS (50 and 200 mug/mL), or both together on human OA subchondral bone osteoblasts, in the presence or absence of 1,25(OH)2D3 (vitamin D3) (50 nM), was determined on the bone biomarkers alkaline phosphatase and osteocalcin, on the expression (mRNA) and production (enzyme-linked immunosorbent assay) of bone remodelling factors OPG and RANKL, and on the pro-resorptive activity of these cells. For the latter experiments, human OA osteoblasts were incubated with differentiated peripheral blood mononuclear cells on a sub-micron synthetic calcium phosphate thin film. Data showed that CS and GS affected neither basal nor vitamin D3-induced alkaline phosphatase or osteocalcin release. Interestingly, OPG expression and production under basal conditions or vitamin D3 treatment were upregulated by CS and by both CS and GS incubated together. Under basal conditions, RANKL expression was significantly reduced by CS and by both drugs incubated together. Under vitamin D3, these drugs also showed a decrease in RANKL level, which, however, did not reach statistical significance. Importantly, under basal conditions, CS and both compounds combined significantly upregulated the expression ratio of OPG/RANKL. Vitamin D3 decreased this ratio, and GS further decreased it. Both drugs reduced the resorption activity, and statistical significance was reached for GS and when CS and GS were incubated together. Our data indicate that CS and GS do not overly affect cell integrity or bone biomarkers. Yet CS and both compounds together increase the expression ratio of OPG/RANKL, suggesting a positive effect on OA subchondral bone structural changes. This was confirmed by the decreased resorptive activity for the combination of CS and GS. These data are of major significance and may help to explain how these two drugs exert a positive effect on OA pathophysiology.

Show MeSH
Related in: MedlinePlus