Effects of Growth Differentiation Factor-5 on the Intervertebral Disc−In Vitro Bovine Study and In Vivo Rabbit Disc Degeneration Model Study

Abstract

A single injection of rhGDF-5 has a reparative capacity on intervertebral discs, presumably based on its effects to enhance extracellular matrix production in vitro.

PDGF, bFGF and IGF-I stimulate the proliferation of intervertebral disc cells in vitro via the activation of the ERK and Akt signaling pathways

“…The response of IVD cells to the above growth factors has been studied in both in vitro and in vivo systems, since it has been proposed that the clinical application of growth factors could represent a new therapeutic intervention against disc degeneration [7,24,47]. Most of the studies, however, are focusing on the effect of growth factors on the production and/or degradation of ECM, and only some of them are dealing with growth factor-induced cell proliferation.…”

New Challenges for Intervertebral Disc Treatment Using Regenerative Medicine

“…This model type has been used to test the efficacy of growth factor therapies. 65,86,87 However, care has to be used in interpreting the cellular response because the NP of rats and rabbits contain a large number of notochordal cells that have been shown to have a metabolic activity different from adult human NP cells. 88 Yet, when disc degeneration is first induced (by means such as a disc puncture, enzyme injection, or compression), notochordal cells may eventually be replaced with fibrochondrocytic and chondrocytic cells, 89,90 generating a phenotype that may be more representative of human adult discs.…”

“…Because there are significant differences in histology during development and aging, experimental levels of each animal should always be assessed together with an internal control level. There are several histological grading systems 65,102 and MRI grading systems, 103,104 and it is important that some standardization be established by the research community. Recently developed techniques, such as T2 mapping and T1rho, can be used to quantify the quality of matrix in both the NP and AF of small animals if the higher magnet, 3T MRI, is used.…”

“…For example, 5-6-month-old rabbits were shown to have changes similar to 2-year-old rabbits in an anular puncture model. 65,101 Radiographic analyses need to be carefully performed. Mal-alignment of the X-ray beam and positioning error of the spine are major sources of error.…”

Interspinous Distraction Device U May Avoid Posterior Artrothesis in the Future?

“…After the beginning of the degenerative disc process originates a loss of height of the same, which causes alteration biomechanics of facet joints, which hypertrophies and causes lumbar canal stenosis [2] and, in turn, a thickening and bending occurs of the yellow ligament [3] that further aggravates stenosis. Various procedures have been investigated to treat the degeneration of the intervertebral disc, with methods biological (implantation of stem cells [4,5], proteins morphogenetic [6][7][8], tissue growth factors [9] that until now have not been successful, or through more aggressive surgical techniques such as disc prosthesis or fixation of the affected disc segment, arthrodesis. Another alternative is the socalled dynamic stabilization, that has been defined as a system that could alter favourably the movement and the transmission of load of a segment spinal mobile, without the intention of merging said segment [10] and avoid the cause of the pain [11].…”