The Effect of Link-N, sLink-N and Mesenchymal Stem Cells on Canine Intervertebral Disc Degeneration

Abstract

BACKGROUND Intervertebral disc disease (IVDD) is a progressive degenerative disease in humans and dogs. Current treatments only relieve the pain on the short term. Several regenerative treatment strategies employ growth factors and mesenchymal stem cells (MSC’s). A newly developed synthetic peptide – Link-N – has been reported to be promising for intervertebral disc (IVD) regeneration. It has a positive effect on the production of collagen type I, II and X and proteoglycan by nucleus pulposus (NP) cells and stimulates cell proliferation. This effect may also be obtained by the biologically active part of Link-N (1-16), short Link-N (1-8). AIM OF THE STUDY Define the effect of Link-N, sLink-N and Link-N and sLink-N in combination with MSC’s on canine IVDD. HYPOTHESIS sLink-N will be as effective as Link-N on NP cells. MSC’s will have an additive effect on the (s)Link-N effect. STUDY DESIGN Real time quantitative PCR was performed on micro-aggregates of nucleus pulposus (NP) cells and micro-aggregates of NP cells and MSC’s of Beagle donors without treatment or treated with TGF-β1, Link-N or sLink-N. The gene expression of collagen type I, II and X, aggrecan, SOX 9, BMPR 2, MMP-9, MMP-13, TIMP-1, ADAMTS 5, ID 1, Pai 1, ALK 1, ALK 5, Cyclin-D1, caspase 3, BCL 2 and BAX were evaluated to examine the effect of (s)Link-N on degenerated NP cells. RESULTS Treatment with sLink-N showed no statistically significant changes in gene expression compared to untreated NP cells. BMSC’s showed statistically significant upregulation of collagen I and MMP-9 compared to cultures without BMSC’s. No statistically significant changes in gene expression were seen in other culture conditions. CONCLUSION Human Link-N and sLink-N have no effect on degenerated canine NP cells. Combining human Link-N or sLink-N with canine BMSC’s does not exert an additive trophic effect on canine NP cells.