Aims

The aims of this study were to describe the prevalence of previous lumbar surgery in patients who undergo total hip arthroplasty (THA) and to investigate their patient-reported outcomes (PROMs) one year post-operatively.

Introduction

In degenerative disorders of the spine such as disc herniation, intervertebral discs can affect neural tissue, which may result in pain as demonstrated in both basic science and clinical investigations. Previous in vitro and in vivo studies have shown that notochordal cells and chondrocyte-like cells in nucleus pulposus affect nervous tissue differently. The aim of the present study was to evaluate the morphology of spinal neural tissue in an in vivo rat model following application of cells derived from nucleus pulposus.

Introduction Bone morphogenetic protein-7 (BMP-7) is known to stimulate both cellular proliferation and extracellular matrix synthesis in the intervertebral disc but its protective role in apoptosis is unknown. The aim of this study was to determine whether BMP-7 protect cultured intervertebral disc cells following stimulation of apoptosis.

Methods Nucleus pulposus tissues were obtained from consent individuals under surgical procedures and digested with collagenase prior to culturing. Cellular apoptosis was achieved by either tumor necrosis factor-alpha (TNF-β) or hydrogen peroxide (H2O2) incubation. BMP-7 (Stryker) was used at 100ng/ml, 5 hours prior to the addition of apoptotic stimulation. Cellular apoptosis was detected by TUNEL assay, caspase-3 activity and caspase-3 protein expression. Cellular proliferation and viability was assayed by H3-thymidine incorporation and MTS assay respectively. Collagen II and aggrecan protein levels were measured using western blots and immunostaining. Proteoglycan synthesis was determined by (35)S-sulfate incorporation method. Nitric oxide and alkaline phosphatase activity were measured.

Results Both extrinsic and intrinsic apoptotic pathways were induced by TNF-β or hydrogen peroxide with increased proteolytic activity of caspase-3 as well as cellular shrinkage and nuclear condensation. Addition of BMP-7 prior to stimulation of apoptosis resulted in complete block of the apoptotic effects of both inducers as well as the cellular nitric oxide induced by TNF-β and BMP-7 increases cellular viability, proliferation and extracellular matrix production in an apoptotic environment with no osteoblastic activity induction of discal cells.

Discussion BMP-7 prevents apoptosis of cultured human disc cells induced by either tumor necrosis factor-alpha (TNF-β) or hydrogen peroxide. Induction of apoptosis led to down regulation of extracellular matrix proteins, decreased cell viability, morphological changes and activation of caspase-3, however addition of BMP-7 alone prevented the effects observed. One possible mechanism of the anti-apoptotic effects of BMP-7 was shown by its retardation of the elevated levels of TNF-β induced nitric oxide.

Introduction The mechanisms underlying chronic back pain are not well understood, however, disc degeneration and facet joint arthrosis have been suggested to be two major pain sources. Nitric oxide (NO) is an oxygen free radical which is involved in variety physiological and pathological events. Increased concentrations of NO have been demonstrated with direct or indirect methods in temporomandibular (Takahashi T et al. Oral Surg Oral Med Oral Pathol Oral Radiol Endod.1999) and knee joints (Karan A et al. Clin Rheumatol. 2003) with osteoarthrosis. The aims of the study were 1. To investigate if real-time NO concentrations can be measured in the perifacetal region and 2. To estimate perifacetal NO levels in patients with facet joint osteoarthrosis associated chronic low back pain and compare it with that of healthy controls, and 3. To investigate if perifacetal NO levels is discriminative for subsets of patients with facet joint osteoarthrosis.

Methods Patients with at least six months duration of chronic low back pain with signs of facet joint osteoarthrosis on CT and/or MRI, were included in the study (n=26). Healthy volunteers were enrolled as controls (n=7). A detailed questionnaire including visual analogue scale (VAS) was completed by the patients before and six weeks after the NO measurements. Nitric oxide was measured with a custom designed electrochemical real-time nitric oxide sensor (World Precision Instruments, Sarasota, Fl). The NO sensor has a detection limit of less than 0.3 nM, a linear response to NO concentrations up to 100 μM and can discriminate between NO and closely related substances such as nitrite (Zhang X et al; Electroanalysis 2002). The NO sensor was inserted into the facet joint through a 20 gauge needle under fluoroscopic guidance in patients and controls. All patients received corticosteroids (0.4 ml Celestone®) and local anaesthetic (0.5–1.0 ml Marcain®) in the perifacetal region following the NO measurements. Descriptive parameters are expressed as mean (± SEM) and Mann-Whitney’s test was used for statistical comparison between groups.

Results It was possible to obtain NO measurements from all participants. No adverse effects were noted. The patients with chronic low back pain demonstrated 3-fold higher concentrations of nitric oxide in the perifacetal region compared to the healthy controls (1.66±1.39 vs. 0.46±0.37 nM, p=0.007). No association between nitric oxide concentration and pain-duration or pain-level (VAS) was detected. However, patients with a positive response to local anaesthetics and corticosteroid injection (detected as a reduction of VAS at a minimum of 20 mm) at the six week follow-up visit had 25% higher concentrations of nitric oxide when compared to patients who had a less than 20 mm decrease in VAS. p=0.02

Discussion The study demonstrates that measurement of NO with a real time-sensor around the facet joints is feasible and safe. The findings of higher concentrations of NO in the perifacetal region in chronic low back patients compared to healthy controls indicate that the degenerative process of the joints may cause increased NO production. Patients that responded to corticosteroid/local anaesthetic infiltration had higher NO concentrations in the perifacetal region compared to patients without response. This observation indirectly suggests a more pronounced inflammatory process in the responding patients.

Introduction Intervertebral disc degeneration may cause chronic low back pain. Disc degeneration is characterized by dysfunctional cells and a decrease in extra-cellular components. Bone marrow derived mononuclear cells are a heterogeneous cell population which contains mesenchymal stem cells. Transplantation of stem cells and progenitor cells may provide a new approach to treat disc degeneration, but it is unclear if transplanted cells can survive and differentiate in the non-vascularized disc.

Methods Bone marrow was collected from syngeneic Sprague-Dawley rats and mononuclear cells were isolated. The cells were labelled with a fluorescence dye (Cell Tracker Orange) and suspended in PBS. 10–20μl of the cell suspension (1–2x10⁵ cells/disc) was transplanted into coccygeal discs in 12 syngeneic rats. For each rat two discs were cell transplanted and one disc served as control. The rats were sacrificed after 0, 7, 14 or 21 days. For each time point the discs from one animal were saved for routine histological staining. The cell transplanted discs of the other animals (n=4 discs per time point) were formalin-fixed, frozen and sectioned together with the control discs. Frozen disc sections were visualized with fluorescence microscopy and the number of transplanted cells assessed. Expression of collagen II, a marker of chondrocytes and chondrocyte-like cells in the disc, was assessed in the transplanted cells using immunofluorescence technique.

Results All cell-suspension injected discs contained transplanted bone-marrow cells. The discs within each time-group demonstrated a large variation in number of detected cells. There was a decrease in detected cells at 7, 14 and 21 days compared to day 0. Transplanted cells expressed collagen II after 21 days but not after 7 and 14 days.

Discussion The results suggest that transplanted bone marrow-derived mononuclear cells can survive and differentiate within the intervertebral disc. Further studies in models of disc degeneration are warranted to investigate the regenerative potential of the disc following cell transplantation.