Introduction and Objective

Global prevalence of obesity has risen almost three-fold between 1975 and 2016. Alongside the more well-known health implications of obesity such as cardiovascular disease, cancer and type II diabetes, is the effect of male obesity on testosterone depletion and hypogonadism. Hypogonadism is a well-known contributor to the acceleration of bone loss during aging, and obesity is the single biggest risk factor for testosterone deficiency in men. Understanding the micro and macro structural changes to bone in response to testosterone depletion in combination with a high fat ‘Western’ diet, will advance our understanding of the relationship between obesity and bone metabolism. This study investigated the impact of surgically induced testosterone depletion and subsequent testosterone treatment upon bone remodelling in mice fed a high fat diet.

Introduction and Objective

Intervertebral disc (IVD) degeneration accompanying with low back pain is a serious worldwide problem. Even though, surgical treatments are available for pain relief, there is an urgent need to establish enduring cell-based remedies. Notochordal (NC) cells as the ancestor of nucleus pulposus (NP) cells in human IVD are a promising therapeutic target. It has been reported that the loss of NC cells after childhood could promote the onset of disc degeneration. Thus, we firstly, aimed to optimise the culture of NC cells in vitro without using the FCS in alginate (3D) culture systems, secondly, investigate their behaviour in healthy and degenerate niche and lastly, co-culture these cells with degenerated NP cells to assess their regeneration potentials.

Purpose and Background

The intervertebral disc is constantly subjected to forces generated by movement. But degeneration can disrupt normal biomechanics, generating uneven and complex loading patterns. Evidence suggests that these forces are converted into voltages through different mechanisms, such as streaming potentials. This implicates voltage-gated ion channels in the biological remodelling response of the disc to loading. These signalling pathways have not been studied, and this incomplete understanding of disc mechanotransduction may hinder regenerative therapies. The purpose of this study is to identify and determine the role of voltage-gated ion channels in the intervertebral disc and to investigate any changes in degeneration.

Objective and Background: Interleukin 1 has been implicated in the progression of degenerative disc disease, however little data is available on the expression and production of IL-1 within degenerate discal cells. A few studies, have investigated herniated disc tissue but the results from these studies have been inconsistent. This study investigated the gene expression of IL-1 α, β, Ra and the receptor type I in discs removed at surgery from 7 prolapsed, 3 Scoliosis and 15 Degenerative discs (DD). In addition immunohistochemistry (IHC) was used to localise IL-1 α and IL-1 β within normal, and degenerate discs.

Methods: Human IVD tissue was obtained from disc replacement surgery and separated into nucleus pulposus (NP) and annulus fibrosus (AF) tissue, cell isolation using collagenase treatment was carried out, and RNA extraction on the cells performed immediately. Real time RT-PCR was then used to investigate gene expression of IL-1 gene family. IHC for IL-1 α and IL-1 β was also performed on paraffin embedded normal and degenerate disc samples.

Results: Expression of the IL-1 family genes was present at low levels within prolapsed disc samples. In contrast levels within scoliosis patents were the highest of the 3 disease states, however in both prolapsed discs and those from scoliosis patients a balance of IL-1 α/β to IL-1 Ra existed. Within samples from DD this balance was lost, with levels of IL-1 α and IL-1 β greatly exceeding levels of IL-1 Ra. In addition levels of IL-1 α and β showed an increase with age and were highest in those samples from the AF than the NP. IHC demonstrated both IL-1 α and IL-1 β protein within the NP and AF cells of the degenerate discs.

Conclusion: This study has demonstrated the mRNA expression of all members of the IL-1 family within IVD and in addition the chondrocytes within the disc produced IL-1 α and IL-1 β protein. The imbalance of IL-1 α/β to IL-1 Ra within those samples from degenerate discs but not prolapsed or scoliotic discs suggests a role for IL-1 within discal degeneration.

Background: Current treatments for Low back pain (LBP) are often empirical and few directed at the underlying disorder, altered discal cell metabolism, which precipitates the problem. The use of gene therapy to manipulate discal metabolism to treat LBP is an interesting possibility. The Intervertebral disc (IVD) is a therapeutic target in LBP, and one approach to gene therapy would be to isolate IVD chondrocytes (IVDC) and transfer genes Ex Vivo into these cells. Subsequent reinjection of these genetically altered cells into the lumbar IVD, would permit the expression of the trans-gene in vivo, generating the therapeutic protein within the IVD.

Methods: To test the viability of this approach, we isolated human IVDC from patients undergoing surgery, grew them Ex vivo and transfected them with the marker gene LacZ, using an adenovirus vector and the CMV promoter. Expression of the gene was then measured using X-gal staining for the gene product ~-galactosidase.

Results: IVDC infected with adenovirus/CMV-LacZ showed maximal LacZ expression 2 days post infection, with almost 50% of cells displaying X-gal positivity within monolayer cultures and 100% infection within alginate culture, gene expression was maintained up to 4 weeks and control cultures showed no LacZ expression.

Conclusion: This study shows that human IVDC can be transfected with a foreign gene using the adenovirus vector. The gene transduction of a therapeutic gene into IVDC, could provide long lasting effect. In addition the use of inducible promoters could allow for the autoregulation of gene expression.