Investigation of the direct effects of salmon calcitonin on human osteoarthritic chondrocytes.
BACKGROUND
Calcitonin has been demonstrated to have chondroprotective effects under pre-clinical settings. It is debated whether this effect is mediated through subchondral-bone, directly on cartilage or both in combination. We investigated possible direct effects of salmon calcitonin on proteoglycans and collagen-type-II synthesis in osteoarthritic (OA) cartilage.


METHODS
Human OA cartilage explants were cultured with salmon calcitonin [100 pM-100 nM]. Direct effects of calcitonin on articular cartilage were evaluated by 1) measurement of proteoglycan synthesis by incorporation of radioactive labeled 35SO4 [5 microCi] 2) quantification of collagen-type-II formation by pro-peptides of collagen type II (PIINP) ELISA, 3) QPCR expression of the calcitonin receptor in OA chondrocytes using four individual primer pairs, 4) activation of the cAMP signaling pathway by EIA and, 5) investigations of metabolic activity by AlamarBlue.


RESULTS
QPCR analysis and subsequent sequencing confirmed expression of the calcitonin receptor in human chondrocytes. All doses of salmon calcitonin significantly elevated cAMP levels (P < 0.01 and P < 0.001). Calcitonin significantly and concentration-dependently [100 pM-100 nM] induced proteoglycan synthesis measured by radioactive 35SO4 incorporation, with a 96% maximal induction at 10 nM (P < 0.001) corresponding to an 80% induction of 100 ng/ml IGF, (P < 0.05). In alignment with calcitonin treatments [100 pM-100 nM] resulted in 35% (P < 0.01) increased PIINP levels.


CONCLUSIONS
Calcitonin treatment increased proteoglycan and collagen synthesis in human OA cartilage. In addition to its well-established effect on subchondral bone, calcitonin may prove beneficial to the management of joint diseases through direct effects on chondrocytes.
Sondergaard
Bodil-Cecilie
BC
Nordic Bioscience A/S, Herlev Hovedgade 207, 2730 Herlev, Denmark. bcs@nordicbioscience.com
Madsen
Suzi H
SH
Segovia-Silvestre
Toni
T
Paulsen
Sarah J
SJ
Christiansen
Thorbjorn
T
Pedersen
Christian
C
Bay-Jensen
Anne-Christine
AC
Karsdal
Morten A
MA
D000368:Aged; D000818:Animals; D002116:Calcitonin / Q000494:pharmacology* / Q000627:therapeutic use; D002358:Cartilage, Articular / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects* / Q000378:metabolism; D024043:Collagen Type II / Q000096:biosynthesis / Q000187:drug effects; D000242:Cyclic AMP / Q000378:metabolism; D005260:Female; D006801:Humans; D008875:Middle Aged; D010003:Osteoarthritis / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D010078:Oxazines; D010455:Peptides / Q000378:metabolism; D011509:Proteoglycans / Q000187:drug effects / Q000378:metabolism; D018003:Receptors, Calcitonin / Q000235:genetics; D015398:Signal Transduction / Q000502:physiology; D013194:Staining and Labeling; D013462:Sulfur Radioisotopes / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology; D014966:Xanthenes
D024043:Collagen Type II; D010078:Oxazines; D010455:Peptides; D011509:Proteoglycans; D018003:Receptors, Calcitonin; D013462:Sulfur Radioisotopes; D014966:Xanthenes; C005843:resazurin; C028815:salmon calcitonin; D002116:Calcitonin; D000242:Cyclic AMP