Chronic low back pain (CLBP) is the most common cause of disability worldwide, and lumbar spine fusion (LSF) is often chosen to treat pain caused by advanced degenerative disease when clinical treatment failed certain cases, the post-surgical outcomes are not what was expected. Several studies highlight how important are. In psychological variables during the postoperative spine surgery period. The aim of this study is to assess the role of preoperative depression on postoperative clinical outcomes. We included patients who underwent LSF since December 2021. Preoperative depression was assessed administering Beck Depression Inventory questionnaire (BDI). And pain and disability were evaluated at 1, 3, and 6 months, administering respectively Visual Analogic Scale (VAS) and Oswestry Disability Index (ODI). As statistical analysis Mann-Whitney test was performed. We included 46 patients, 20 female (43,5%) and 26 male (56,5%) with an average age of 64,2. The population was divided in two groups, fixing the BDI cut-off point at 10. Patients with BDI < 10 points (N=28) had normal mental health status, instead patients with BDI > 10 points (N=16) had depressive disorders. At 3 months patients with healthy mental status reported statistically significant reduction of pain (U = 372,5, p = .006) and improvement of disability but without statistical significancy (U = 318, p = 0,137). At 6 months patients without psychological disease reported statistically significant reduction of pain (U = 342, p = 0,039) and disability (U = 372,5, p = 0,006).

This study demonstrates the correlation between pre-existing depressive state and poorer clinical outcomes after spine surgery. These results are consistent with the literature. Therefore, during the surgical decision making it is crucial to take psychological variables into account in order to predict the results after surgery and inform patients on the potential influence of mental status.

Low back pain (LBP) is the main cause of disability worldwide and is primarily triggered by intervertebral disc degeneration (IDD). Although several treatment options exist, no therapeutic tool has demonstrated to halt the progressive course of IDD. Therefore, several clinical trials are being conducted to investigate different strategies to regenerate the intervertebral disc, with numerous studies not reaching completion nor being published. The aim of this study was to analyze the publication status of clinical trials on novel regenerative treatments for IDD by funding source and identify critical obstacles preventing their conclusion.

Prospective clinical trials investigating regenerative treatments for IDD and registered on ClinicalTrials.gov were included. Primary outcomes were publication status and investigational treatment funding. Fisher's exact test was utilized to test the association for categorical variables between groups.

25 clinical trials were identified. Among these, only 6 (24%) have been published. The most common source of funding was university (52%), followed by industry (36%) and private companies (12%). Investigational treatments included autologous (56%) or allogeneic (12%) products alone or in combination with a carrier or delivery system (32%). The latter were more likely utilized in industry or privately funded studies (Fig. 1, p=0.0112). No significant difference was found in terms of funding regarding the publication status of included trials (Table 1, p=0.9104).

Most clinical trials investigating regenerative approaches for the treatment of IDD were never completed nor published. This is likely due to multiple factors, including difficult enrollment, high dropout rate, and publication bias³. More accurate design and technical support from stakeholders and clinical research organization (CROs) may likely increase the quality of future clinical trials in the field.

For any figures or tables, please contact the authors directly.

Despite promising results in attempting intervertebral disc regeneration, intradiscal cell transplantation is affected by several drawbacks, including poor viability in the harsh disc environment, low cost-effectiveness, and immunogenic/tumorigenic concerns. Recently, the development of cell-free approaches is gaining increasing interest in the field, with a particular regard towards extracellular vesicles (EVs). Nucleus pulposus cell (NPC) progenitors characterized by Tie2 expression have shown a higher chondrogenic differentiation potential compared to MSCs. The aim of this study was to investigate the putative regenerative effects of EVs isolated from Tie2-overexpressing NPC progenitors on degenerative NPCs.

NPCs were isolated from young donors and underwent an optimized culture protocol to maximize Tie2 expression (NPCs^Tie2+) or a standard protocol (NPCs^STD). Following EV characterization, NPC isolated from patients affected by intervertebral disc degeneration (IDD) were treated with either NPCs^Tie2+-EVs or NPCs^STD-EVs. Cell proliferation and viability were assessed with the CCK-8 assay. Cell apoptosis and necrosis were evaluated with the Annexin V/PI assay. Cell senescence was investigated with b-galactosidase staining. EV uptake was assessed with PKH26 staining of EVs under confocal microscopy.

Treatment with EVs isolated from young NPC donors significantly increased degenerative NPC viability, especially in samples treated with NPCs^Tie2+-EVs. Likewise, NPCs^Tie2+-EVs significantly reduced cell senescence and did not show to exert necrotic nor apoptotic effects on recipient cells. Furthermore, EV uptake was successfully observed in all treated cells.

NPCs^Tie2+-EVs demonstrated to significantly enhance degenerative NPC viability, senescence and apoptosis. The use of committed progenitors naturally residing the in the nucleus pulposus may optimize EV regenerative properties and constitute the basis for a new therapy for IDD.

In the last decades, the use of artificial intelligence (AI) has been increasingly investigated in intervertebral disc degeneration (IDD) and chronic low back pain (LBP) research. To date, several AI-based cutting-edge technologies, such as computer vision, computer-assisted diagnosis, decision support system and natural language processing have been utilized to optimize LBP prevention, diagnosis, and treatment. This talk will provide an outline on contemporary AI applications to IDD and LBP research, with a particular attention towards actual knowledge gaps and promising innovative tools.

Low back pain (LBP) is a worldwide leading cause of disability. Treatment of intervertebral disc (IVD) with stem cells has been used on degenerate discs (IDD), cause of around 40% of LBP cases. Despite pain reduction, clinical studies' follow-up have not shown a structural IVD improvement. A valid alternative may be the use of notocordal cells (NC) or their precursors. Mesendoderm progenitor cells (MEPC) have the ability to replicate and differentiate toward NC. In this preliminary study we evaluated in a preclinical IDD model the viability and NC differentiation of MEPC derived from induced pluripotent stem cells (iPSC).

MEPC derived from iPSC were developed during the iPSpine project (# 825925), thawed, plated for 24h on laminin and labeled with PKH26.

Two adult sheep were subjected to nucleotomy of five lumbar discs for the induction of IDD. After 5 weeks, 3 degenerated discs were treated with MEPC at 3 different doses (low, medium and high). One sheep was sacrificed after 7 days and one after 30 days. Clinical parameters were collected to evaluate the safety of treatment. Discs were analysed using histological techniques. Survival (PKH26), proliferation (PCNA), notocordal cell differentiation (Brachyury, Cytokeratin 8/18/19, Sox9, Foxa2) and endodermal differentiation (Sox17) were evaluated.

At 7 days from treatment, both sheep lost about 20% of body weight. Only in discs treated with the highest dose PKH26 stained cells were alive up to 30 days. These cells turn out to be: proliferating (PCNA); positive for Brachyury, cytokeratin 8/18/19 and Foxa2; positive for SOX17 in a small percentage.

This preliminary study shows that MEPC, derived from iPSC and injected into ovine discs degenerated by nucleotomy, are able to survive up to 30 days and differentiate within the disc predominantly towards the notocordal phenotype.

Invertebral disc degeneration (IDD) is a degenerative disease involving a variety of musculoskeletal and spinal disorders such as lower back pain (LBP). Secretome derived from mesenchymal stem cells (MSCs) have exerted beneficial effect on tissue regeneration. In this study, the goal was to investigate the paracrine and the anti-inflammatory effects of secretome from interleukin IL1β preconditioned Bone Marrow MSCs (BMSCs) on human nucleus pulposus cells (hNPCs) in a 3D in vitro model.

Secretome was collected from BMSCs (BMSCs-sec) after preconditioning with 10 ng/mL IL1β. hNPCs were isolated from surgical specimens, culture expanded in vitro, encapsulated in alginate beads and treated with: growth medium; IL1β 10 ng/mL; IL1β 10 ng/mL for 24 hours and then BMSCs-sec. We examined: i) cell proliferation and viability (flow cytometry), ii) nitrite production (Griess assay) and ROS quantification (Immunofluorescence) iii) glycosaminoglycan (GAG) amount (DMBB) and iv) gene expression levels of extracellular matrix (ECM) components and inflammatory mediators (qPCR). One-way ANOVA analysis was used to compare the groups under exam and data were expressed as mean ± S.D.

In vitro tests showed an enhancement of hNPCs proliferation after treatment with BMSCs-sec (p ≤ 0.05) compared to IL1β group. After 24 hours, the percentage of dead cells was higher in IL1β treated hNPCs compared to control group and decreased significantly in combined IL1β and BMSCs-sec sample group (p ≤ 0.01). Nitrite and ROS production were significantly mitigated and GAGs content was improved by preconditioned BMSCs-sec (p ≤ 0.05). Furthermore, gene expression levels were modulated by BMSCs-sec treatment compared to controls.

Our results supported the potential use of BMSCs' secretome as a cell-free strategy for IDD, overcoming the side effects of cell-therapy. Moreover, secretome derived from IL1β preconditioned BMSCs was able to reduce hNPCs death, attenuate ECM degradation and oxidative stress counteracting IDD progression.

Acknowledgements: Financial support was received from the “iPSpine” and “RESPINE” Horizon 2020 projects.

The use of intraoperative navigation and robotic surgery for minimally invasive lumbar fusion has been increasing over the past decade. The aim of this study is to evaluate postoperative clinical outcomes, intraoperative parameters, and accuracy of pedicle screw insertion guided by intraoperative navigation in patients undergoing lumbar interbody fusion for spondylolisthesis. Patients who underwent posterior lumbar fusion interbody using intraoperative 3D navigation since December 2021 were included. Visual Analogue Scale (VAS), Oswestry Disability Index (ODI), and Short Form Health Survey-36 (SF-36) were assessed preoperatively and postoperatively at 1, 3, and 6 months. Screw placement accuracy, measured by Gertzbein and Robbins classification, and facet joint infringement, measured by Yson classification, were assessed by intraoperative Cone Beam CT scans performed at the end of instrumentation. Finally, operation time, intraoperative blood loss, hospital stay, and screw insertion time were evaluated. This study involved 50 patients with a mean age of 63.7 years. VAS decreased from 65.8±23 to 20±22 (p<.01). ODI decreased from 35.4%±15 to 11.8%±14 (p<.01). An increase of SF-36 from 51.5±14 to 76±13 (p<.01) was demonstrated. The accuracy of “perfect” and “clinically acceptable” pedicle screw fixation was 89.5% and 98.4%, respectively. Regarding facet violation, 96.8% of the screws were at grade 0. Finally, the average screw insertion time was 4.3±2 min, hospital stay was 4.2±0.8 days, operation time was 205±53 min, and blood loss was 169±107 ml. Finally, a statistically significant correlation of operation time with hospital stay, blood loss and placement time per screw was found. We demonstrated excellent results for accuracy of pedicle screw fixation and violation of facet joints. VAS, ODI and SF-36 showed statistically significant improvements from the control at one month after surgery.

Navigation with intraoperative 3D images represents an effective system to improve operative performance in the surgical treatment of spondylolisthesis.

This study aimed to investigate the effect of irisin on human nucleus pulposus cells (hNPCs) in vitro. Our hypothesis was that irisin would improve hNPC metabolism and proliferation.

hNPCs were isolated from intervertebral discs and cultured in alginate beads. hNPCs were exposed to phosphate-buffered saline (PBS) or recombinant irisin (r-irisin) at 5, 10 and 25 ng/mL (n=4). Each experiment was performed in triplicate. Cell proliferation was assessed with trypan blue staining-automated cell counting and PicoGreen assay. Glycosaminoglycan (GAG) content was measured using the DMMB assay. Metabolic activity was assessed with the MTT assay and the Griess Reagent System. Gene expression of collagen type II (COL2), matrix metalloproteinase (MMP)-13, tissue inhibitor of matrix metalloproteinase (TIMP)-1 and −3, aggrecan, interleukin (IL)-1β, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-5 was measured by RT-PCR. MTT assay and ADAMTS-5, COL2, TIMP-1 and IL-1β gene expression were evaluated following incubation with 5, 10 and 25 ng/mL r-irisin for 24 hours and subsequent culture with 10 ng/ml IL-1β and vice versa (incubation for 24 hours with IL-1β and subsequent culture with r-irisin).

Irisin increased hNPC proliferation (p<0.001), metabolic activity (p<0.05), GAG content (p<0.01), as well as COL2 (p<0.01), aggrecan (p<0.05), TIMP-1 and −3 (p<0.01) gene expression, while decreasing MMP-13 (p<0.05) and IL-1β (p<0.001) mRNA levels. r-irisin pretreatment of hNPCs cultured in pro-inflammatory conditions resulted in a rescue of metabolic activity (p<0.001) and a decrease of IL-1β (p<0.05) levels. Similarly, incubation of hNPCs with IL-1β and subsequent exposure to r-irisin increased hNPC metabolic activity (p<0.001), COL2 gene expression (p<0.05) and decreased IL-1β (p<0.05) and ADAMTS-5 levels (p<0.01).

Irisin stimulates hNPC proliferation, metabolic activity, and anabolism by reducing IL-1β and catabolic enzyme expression while promoting matrix synthesis.

The purpose of this study was to evaluate the beneficial effects of r-Irisin (IR) on human primary tenocytes (hTCs) in vitro. Indeed, Irisin is secreted from muscles in response to exercise and mediates many beneficial effects on tissues and organs.

Tissue samples (n=3) were analyzed by histology and immunohistochemistry for αVβ5 receptor. hTCs isolated, culture expanded were treated with: 1) RPMI medium as control; 2) IR at different concentrations; 3) IL-1β; 4) pre-treated with IL-1β for 24 h and then co-treated with IR; 5) pre-treated with IR for 24 h and then co-treated with IL-1β. We evaluated: cell metabolic activity (MTT); cell proliferation (trypan blue staining and PicoGreen); nitrite concentration (Griess). The analysis were performed in triplicate for each donor and each experiment was repeated at least three times. Data were expressed as mean ± S.D. One-way ANOVA analysis was used to compare the groups under exam.

We found the presence of the αVβ5 receptor on hTCs plasma membrane supporting the potential interaction with irisin. Cell proliferation was significantly increased with IR at 5, 10 and 25 ng/mL. IR 25 ng/mL after IL1β pre-treatment was able to counteract the increase of nitrite production (p < 0.001) compared to the inflamed hTCs (p < 0.01; p < 0.0001), as well as IR at 10 and 25 ng/ml showed a protective role from oxidative damage. We observed a significant increase in cell metabolic viability in culture under IR at 5 and 25 ng/mL (p < 0.001; p < 0.05) in the pre-treated IR groups, whereas IR showed anti-inflammatory effects at the highest concentration of r-Irisin (p < 0.05).

This is the first study reporting the capability of irisin to attenuate tendinopathy in vitro by acting on acute inflamed tenocytes. Our results confirmed and highlighted the potential cross-talk mechanism between muscle and tendon.

The aim of this study was to investigate the regenerative effects of Wharton's Jelly Mesenchymal Stem Cells (WJ-MSCs) derived exosomes (WJ-Exos) on human nucleus pulposus cells (hNPCs) in an in vitro 3D model.

WJ-Exos were isolated by tangent flow filtration of WJ-MSCs conditioned media and characterized by TEM, WB for markers expression and quantified with NTA. WJ-Exos PKH26-labeled uptake in hNPCs was detected by confocal microscopy. hNPCs, isolated from surgical specimens (n=4), culture expanded in vitro and encapsulated in alginate beads, were pre-treated with IL1β (10 ng/ml) for 24 hours, then with WJ-Exos at 10, 50 and 100 µg/ml. Cells with growth medium were used as control. We examined: i) cell proliferation and viability (flow cytometry), ii) nitrite production (Griess) iii) glycosaminoglycan (GAG) amount (DMBB), iv) histological staining for extracellular matrix (ECM) analysis and v) gene expression levels of catabolic and anabolic genes (qPCR). The investigations were performed in triplicate for each donor. One-way ANOVA analysis was used to compare the groups under exam and data were expressed as mean ± S.D.

A dose dependent increase in hNPCs proliferation was noticed at all exos concentrations under study. Cell death decreased significantly in WJ-Exos 50 µg/ml samples (p ≤ 0,05) compared to IL1β treated hNPCs. Nitrite production was significantly attenuated at 10µg/ml of WJ-Exos (p ≤ 0,01). GAG content and histological analysis showed a difference in ECM synthesis between treated and untreated hNPCs (p ≤ 0,05). Catabolic and inflammatory markers were modulated by WJ-Exos at 100 µg/ml concentration (p ≤ 0,05) whereas 10 µg/ml group increased anabolic gene expression levels (p ≤ 0,05).

These findings offer new opportunities for the potential use of exosomes as an attractive alternative cell-free strategy of IDD. WJ-MSC exosomes ameliorate hNPCs growth and viability, attenuate ECM degradation and oxidative stress-related IDD progression after IL1β stimulation.

Financial support was received from the “iPSpine” and “RESPINE” Horizon 2020 projects.

With the coronavirus disease 2019 (COVID-19) pandemic, remote working has been ubiquitously implemented to reduce disease transmission via minimization of in-person interactions. Low back pain (LBP) is the first cause of disability worldwide and is frequently reported by workers with sedentary occupations. This cross-sectional study aimed to assess the role of remote working in a population of adults affected by LBP through an online questionnaire.

We enrolled 136 teleworkers affected by LBP. A total of 101 responses were received and 93 suitable questionnaires were included in the final analysis. Demographic data, remote working features and tasks, and LBP burden were analysed. The psychological burden of remote working was evaluated with the World Health Organization Five Well-Being Index (WHO-5) and the Patient Health Questionnaire-2 (PHQ-2). LBP severity was evaluated using a visual analog scale (VAS). LBP-related disability was assessed using the Oswestry Disability Index (ODI). The effect of LBP on working capacity was examined with the Occupational Role Questionnaire (ORQ). Independent risk factors related to LBP worsening were identified using a multivariate logistic regression model.

LBP severity was significantly higher compared to previous in-person working (p<0.0001) as well as average weekly work hours (p<0.001). Furthermore, the risk of LBP deterioration was associated with being divorced (OR: 4.28, 95% CI: 1.27-14.47; p=0.019) or living with others (OR: 0.24, 95% CI: 0.07-0.81; p=0.021), higher ill-being (OR: 0.91, 95% CI: 0.83-0.99; p=0.035) and depression scores (OR: 1.38, 95% CI: 1.00-1.91; p=0.048), as well as having reported unchanged (OR: 0.22, 95% CI: 0.08-0.65; p=0.006) or decreased job satisfaction (OR: 0.16, 95% CI: 0.05-0.54; p=0.003) and increased stress levels (OR: 3.00, 95% CI: 1.04-8.65; p=0.042).

These findings highlight key factors to consider for improving remote workers’ physical and mental wellbeing and decrease their LBP burden.

Intervertebral disc degeneration (IDD) affects more than 80% of the population all over the world. Current strategies for the treatment of IDD are based on conservative or surgical procedures with the aim of relieving pain. Mesenchymal stem cell (MSC) transplantation has emerged as a promising therapy in recent decades, but studies showed that the particularly hostile microenvironment in the intervertebral disc (IVD) can compromise cells survival rate. The use of exosomes, extracellular vesicles released by various cell types, possess considerable economic advantages including low immunogenicity and toxicity. Exosomes allow intercellular communication by conveying functional proteins, RNA, miRNA and lipids between cells. The purpose of this study is to assess the therapeutic effects of exosomes derived from Wharton Jelly mesenchymal stromal cells (WJ-MSC) on human nucleuspulposus cells (hNPC) in an in vitro 3D culture model.

Exosomes (exos) were isolated by tangential flow filtration of WJ-MSC conditioned media and characterized by: quantification with BCA test; morphological observation with TEM, surface marker expression by WB and size evaluation by NTA. Confocal microscopy has been used to identify exosomes marked with PKH26 and monitor fusion and/or incorporation in hNPC. hNPC were isolated from waste surgical material from patients undergoing discectomy (n = 5), expanded, encapsulated in alginate beads and treated with: culture medium (control group); WJ-MSC exos (WJ-exos) at different concentrations (10 μg/ml, 50 μg/ml and 100 μg/ml).

They were then analysed for: cell proliferation (Trypan Blu); viability (Live/Dead Assay); quantification of nitrites (Griess) and glycosaminoglycans, GAG (DMBB). The hNPC in alginate beads treated for 7 days were included in paraffin and histologically analysed to determine the presence of extracellular matrix (ECM) components. Finally, the expression levels of catabolic and anabolic genes were evaluated through real-time polymerase chain reaction (qPCR).

All concentrations of WJ-exos under exam were capable to induce a significant increase in cell proliferation after 10 and 14 days of treatment (p < 0.01 and p < 0.001, respectively). Live/Dead assay showed a decrease in cell death at 50 μg/ml of WJ-exos (p < 0.05). While cellular oxidative stress indicator, nitrite production, was reduced in a dose-dependent way and statistically significant only with 100 μg/ml of WJ-exos (p < 0.05). WJ-exos at 10 and 100 μg/ml induced a significant increase in GAG content (p < 0.05; p < 0.01, respectively) confirmed by Alcian Blu staining. Exos derived from WJ-MSC modulated gene expression levels by increasing expression of ACAN and SOX-9 genes and reducing significantly of IL-6, MMP-1, MMP-13 and ADAMTS-5 levels (p < 0.05; p < 0.01) compared to the control group.

Our results supported the potential use of exosomes from WJ-MSC for the treatment of IDD. Exosomes improved hNPC growth, attenuated ECM degradation and reduced oxidative stress and inflammation. This study offers a new scenario in IVD regeneration, promoting the potential use of extracellular vesicles as an alternative strategy to cell therapy.

Low back pain (LBP) is the leading cause of disability worldwide. Recently, treatment of the intervertebral disc (IVD) with stem cells has been used for the treatment of degenerate discs (IDD) which cause at least the 40% of LBP cases. Despite pain reduction, follow-up in clinical studies have not shown an improvement in the structural integrity of IVD. A valid alternative could be the use of progenitor disc cells (notocordal cells, NC) or of their precursors. Mesendoderm progenitor cells (MEPC) have the ability to replicate and differentiate toward NC. In this preliminary study we evaluated in a preclinical large animal IDD model the viability and NC differentiation of MEPC derived from induced pluripotent stem cells (iPSC).

MEPC, derived from iPSC and developed during the iPSpine project (# 825925), were thawed and plated on laminin for 24h and labeled with PKH26.

Two adult sheep were subjected to nucleotomy of five lumbar discs for the induction of IDD. After 5 weeks, 3 of the 5 degenerate discs were treated with MEPC at 3 different doses (low, medium and high). One sheep was sacrificed after 7 days and the other after 30 days from the treatment injection procedure. Clinical parameters were collected to evaluate the safety of treatment. Discs were paraffin embedded and analysed using histological techniques. Survival (PKH26), proliferation (PCNA), notocordal cell differentiation (Brachyury, Cytokeratin 8/18/19, Sox9, Foxa2) and endodermal differentiation (Sox17) were evaluated.

After the injection of the cells, both sheep lost about 20% of body weight. The analysis showed that only in discs treated with the highest dose the PKH26 stained cells resulted alive after 30 days from the procedure. These cells turn out to be:

This preliminary study shows that MEPC, derived from iPSC and injected into ovine discs degenerated by nucleotomy, are able to survive 30 days from treatment and differentiate within the disc predominantly towards the notocordal phenotype.

Introduction:

Exercise has showed to reduce pain and improve function in patients with discogenic low back pain (LBP). Although there is currently no biologic evidence that the intervertebral disc (IVD) can respond to physical exercise in humans, a recent study has shown that chronic running exercise is associated with increased IVD hydration and hypertrophy1. Irisin, a myokine released upon muscle contraction, has demonstrated to yield anabolic effects on different cell types, including chondrocytes2. This study aimed to investigate the effect of irisin on human nucleus pulposus cells (hNPCs). Our hypothesis is that irisin may improve hNPCs metabolism and proliferation.

Introduction and Objective

Osteoarthritis (OA) represents one of the leading cause of disability all over the world. Cell therapies, mainly based on mesenchymal stem cells (MSCs), have shown to modulate the pathogenesis of OA in basic, preclinical and clinical studies. Adipose tissue (AT) have emerged as a rich and promising source of MSCs called adipose derived stem cells (ASCs). Different systems are available for processing lipoaspirate to purify the samples from oily and haemorrhagic fractions, minimizing the risk of complications and maximizing the biological yield for subsequent grafting. However, few studies compared the efficacy of the different processing devices already used in clinical practice. This study aims to characterize the products obtained by the use of two different systems such as micro-fragmentation or nano-fragmentation comparing them with the starting material (AT) and the collagenase isolated ASCs.

Introduction and Objective

Low back pain (LBP) is a disorder strongly associated with intervertebral disc degeneration (IDD) with an important impact on the quality of life of affected people. To date, LBP treatment is based on conservative methods with the aim to reduce back pain without restoring the degenerative environment of the disc. The main cause of IDD is the drastic reduction of the proteoglycan content within the nucleus pulposus (NP), eventually leading to the loss of disc water content, micro-architecture, biochemical and mechanical properties. A promising approach for disc regeneration is represented by the transplantation of mesenchymal stromal cells (MSCs). The exact mechanism remains unknown. Growing evidence suggests that MSCs can influence cells and modulate cells’ behaviour by secreting a set of bioactive factors. MSCs secretome is composed of several molecules such as soluble protein, lipids, nucleic acids and extracellular vesicles (EVs) involved in inflammation, immunomodulation, cell survival and intercellular communication. The aim of this study was to evaluate the in vitro effects of MSCs secretome on human NP cells (hNPCs) in a 3D culture model with and without inflammatory stimulus.

Minimally invasive surgery for the restoration of bone tissues lost due to diseases and trauma is preferred by the health care system as the related costs are continuously increasing. Recently, efforts have been paid to optimize injectable calcium phosphate (CaP) cements which have been recognized as excellent alloplastic material for osseous augmentation because of their unique combination of osteoconductivity, biocompatibility and mouldability. The sol-gel synthesis approach appears to be the most suitable route towards performing injectable calcium phosphates. Different strategies used to prepare bioactive and osteoinductive injectable CaP are reported. CaP gels complexed with phosphoserine-tethered poly(ε-lysine) dendrons (G3-K PS) designed to interact with the ceramic phase and able to induce osteogenic differentiation of human mesenchymal stem cells (hMSCs) is discussed. Recently, attention has been given to the modification of hydroxyapatite with Strontium (Sr) due to its dual mode of action, simultaneously increasing bone formation (stimulating osteoblast differentiation) while decreasing bone resorption (inhibiting osteoclast differentiation). The effect of systems based on strontium modified hydroxyapatite (Sr-HA) at different composition on proliferation and osteogenic differentiation of hMSC is described. One more approach is based on the use of antimicrobial injectable materials. It has been demonstrated that some imidazolium, pyridinium and quaternary ammonium ionic liquids (IL) have antimicrobial activity against some different clinically significant bacterial and fungal pathogens. Here, we report several systems based on IL at different alkyl-chain length incorporated in Hydroxyapatite (HA) through the sol-gel process to obtain an injectable material with simultaneous opposite responses toward osteoblasts and microbial proliferation.

Intervertebral disc degeneration (IDD) is a major cause of low back pain, which affects 80% of the adult population at least once in their life. The pathophysiological conditions underlying IDD are still poorly understood. Genetic makeup, aging, smoking, physical inactivity and mechanical overloading, especially due to obesity, are among the strongest risk factors involved. Moreover, IDD is often associated with chronic inflammation within disc tissues, which increases matrix breakdown, glycosaminoglycan (GAG) loss and cell death. This micro-inflammatory environment is typical of several metabolic disorders, including diabetes mellitus (DM). As the etiopathogenesis of IDD in diabetic subjects remains scarcely understood, we hypothesised that this may be driven by a DM-induced inflammation leading to a combination of reduced GAG levels, decreased proteoglycan synthesis and increased matrix breakdown within the disc. The objective of the study was to investigate the pathogenesis of IDD in a murine model of type 1 DM (T1DM), namely non-obese diabetic (NOD) mouse.

Total disc glycosaminoglycan (GAG) content, proteoglycan synthesis, aggrecan fragmentation mediated by matrix metalloproteinases (MMPs) and a Disintegrin and Metalloproteinase with Thrombospondin motifs (ADAMTS), glucose transporter (mGLUT1) gene expression and apoptosis (TUNEL assay) were assessed in NOD mice and wild-type euglycemic control mice. Spinal structural and molecular changes were analysed by micro-computed tomography (mCT), histological staining (Safranin-O and fast green) and quantitative immunofluorescence (anti-ADAMTS-4 and 5 antibodies). Statistical analysis was conducted considering the average of 35 samples ± standard error for each measurement, with 95% confidence intervals calculated to determine statistical significance (p-value < 0.05).

IVDs of NOD mice showed increased disc apoptosis (p < 0.05) and higher aggrecan fragmentation mediated by ADAMTS (p < 0.05). However, ADAMTS-4 and −5 did not appear to be involved in this process. The total GAG content normalized to DNA and PG synthesis showed no statistically significant alterations, as well as Safranin O staining. Although not significantly, NOD mice showed reduced glucose uptake. In addition, the vertebral structure of NOD mice at mCT seemed not to be altered.

These data demonstrate that DM may contribute to IDD by increasing aggrecan degradation and promoting cell apoptosis, which may represent early indicators of the involvement of DM in the pathogenesis of IDD.

In the last decade, skeletal muscle has been recognized as an endocrine organ able to release molecules that may act as paracrine or endocrine factors, namely myokines. Among these, irisin is secreted upon muscle contraction after physical exercise (PE) and has been demonstrated to yield anabolic effects on different cell types. Recently, irisin has been shown to improve cortical bone mass, geometry and strength, hence resembling the effect of PE. It has also been reported that irisin levels in the serum and synovial fluid of patients with knee osteoarthritis (OA) were negatively correlated with OA severity. Therefore, we hypothesized that irisin may improve cartilage metabolism and blunt the osteoarthritic process.

Human osteoarthritic chondrocytes (hOAC) were isolated from osteochondral specimens of patients undergoing total knee joint replacement. After in vitro expansion, hOAC were put in a three-dimensional culture system (alginate beads) and treated with either phosphate-buffered saline (control) or irisin (25 ng/mL). After 1 week, the amount of glycosaminoglycans (GAG) was evaluated using dimethylmethylene blue (DMMB) and PicoGreen assays. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to detect interleukin (IL)-1 and -6, matrix metalloproteinase (MMP)-1 and -13, inducible nitric oxide synthase (iNOS) and tissue inhibitor of matrix metalloproteinases (TIMP)-1 and -3 gene expression levels.

hOAC treated with irisin showed a significant higher GAG content compared to the control group (p < 0.01). Moreover, irisin was able to reduce the expression of catabolic (MMP-1, -13, iNOS) and pro-inflammatory (IL-1, IL-6) markers, while incrementing the expression of TIMP-1 and -3 (p < 0.001).

Our results showed that irisin was able to stimulate GAG synthesis and diminish extracellular matrix catabolism in hOAC, demonstrating the existence of a cross-talk between cartilage and muscle possibly supporting the beneficial role of PE on cartilage homeostasis.

Intervertebral disc degeneration (IDD) affects more than 80% of the population and is often linked to a reduction of the proteoglycan content within the nucleus pulposus (NP). The nutritional decline and accumulation of degraded matrix products promote the inflammatory process favoring the onset of disease. Several regenerative approaches based on cell therapy have been explored. Recently, paracrine factors and extracellular vesicles (EVs) such as exosomes have been described to play a fundamental role in the cross-talk between mesenchymal stem cells (MSCs) and NP in the microenvironment. EVs vehicule different molecules: proteins, nucleic acids and lipids involved in intercellular communication regulating the homeostasis of recipient cells. Therefore, MSCs-derived exosomes are an interesting emerging tool for cell-free therapies in IDD.

The aim of this study was to evaluate the in vitro effects of MSCs derived exosomes on human NP cells (hNPCs).

Exosomes were isolated through a multistep ultracentrifugation of bone marrow-MSCs (BM-MSCs) conditioned media (CM), obtained by culturing BM-MSCs without fetal bovine serum (FBS) for 48 hours. Exosomal morphology was characterized by transmission electron microscope (TEM). The exosomes were quantified by bicinchoninic acid assay (BCA) and cryopreserved at –80 °C. hNPCs derived from surgical speciments digested with type II collagenase. After culture expansion in vitro, hNPCs in alginate beads (three-dimensional culture system) were treated with growth medium (controls), exosomes, CM, interleukin-1 beta (IL-1b), IL-1b plus exosomes, IL-1b plus CM. After 24 hours, total RNA was extracted and reverse-transcribed. Gene expression levels of catabolic and anabolic genes were analyzed through real time-polymerase chain reaction (qPCR).

TEM analysis confirmed the cup-shaped vescicles in our preparations. Gene expression levels resulted to be modulated by both exosomes and CM compared to controls. In addition, both treatments were capable to alter the inflammatory stimuli of IL-1b. Interestingly, exosomes were able to change anabolic and catabolic gene expression levels differently from CM.

In our experimental conditions, both exosomes and CM from BM-MSCs could be an interesting alternative strategy in intervertebral disc regeneration, overcoming the costs and translational limits of cell therapy to the clinical practice.

Cartilage neoangiogenesis holds a key role in the development of osteoarthritis (OA) by promoting cartilage degradation with proteoglycan loss, subchondral bone sclerosis, osteophyte formation and synovial hyperplasia. This study aimed to assess the in vivo efficacy of bevacizumab, an antibody against vascular endothelial growth factor (VEGF) in an OA animal model.

24 New Zealand white rabbits underwent anterior cruciate ligament transection in order to spontaneously develop knee OA. Animals were divided into four groups: one receiving a sham intraarticular knee injection (saline) and three groups treated with 5, 10, and 20 mg intraarticular bevacizumab injections. The biological effect of the antibody on cartilage and synovium was evaluated through histology and quantified with the Osteoarthritis Research Society International (OARSI) scores. Immunohistochemical analysis was conducted to investigate type 2 collagen, aggrecan, and matrix metalloproteinase 13 (MMP-13) expression in both cartilage and synovium.

Intraarticular bevacizumab led to a significant reduction of cartilage degeneration and synovial OA alterations. Immunohistochemistry showed a significantly reduced MMP-13 expression in all experimental groups, with the one receiving 20 mg bevacizumab showing the lowest. Furthermore, the antibody showed to increment the production of aggrecan and type 2 collagen after administration of 5, 10, and 20 mg. The group treated with 20 mg showed the highest levels of type 2 collagen expression, while aggrecan content was even higher than in the healthy cartilage.

Intraarticular bevacizumab has demonstrated to effectively arrest OA progression in our model, with 20 mg being the most efficacious dose. By inhibiting cartilage and synovial neoangiogenesis, bevacizumab may serve as a possible disease-modifying osteoarthritis drug (DMOAD) in the next future.

Anterior cruciate ligament injury is the most common and economically costly sport injuries, frequently requiring expensive surgery and rehabilitation. Post-operative knee septic arthritis represents a serious complication with an incidence rate between 0.14% and 1.7%. A common practice to avoid septic arthritis is the “vancomycin wrap”, consisting in the soaking of the graft for 10–15 minutes within a sterile gauze swab previously saturated with 5 mg/mL vancomycin. Even though several studies have been conducted to investigate vancomycin toxicity on different musculoskeletal tissues or cells, little is known about the effect of such antimicrobial on tendon-derived cells.

The aim of this study was to determine the in vitro toxicity of different concentrations of vancomycin at different time points on human primary tenocytes (hTCs).

hTCs were isolated from hamstring grafts of patients undergoing anterior cruciate ligament reconstruction. After expansion, cells were treated with different concentrations of vancomycin (2.5, 5, 10, 25, 50 and 100 mg/mL) for 10, 15, 30 and 60 minutes. In vitro toxicity was evaluated measuring: metabolic activity through the reduction of 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT Assay); cytotoxicity (Live/Dead assay); and cell apoptosis (Annexin V apoptosis kit).

The metabolic activity of hTCs was affected by vancomycin treatment starting from 10 mg/mL at all time points (p < 0.05) and dropped down at 100 mg/mL at all time points (0.05 < p < 0.001). Cells viability resulted to be unaffected only by 2.5 mg/mL vancomycin at all time points. Vancomycin resulted to be cytotoxic starting from 10 mg/mL after 15 minutes of treatment and at all higher concentrations under study at all time points. Cells died when treated with vancomycin concentrations higher than 5 mg/mL but not through apoptosis, as confirmed by negative staining for Annexin V.

In our experimental conditions, vancomycin resulted to be toxic on hTCs at concentrations higher than 5 mg/mL. The use of this antibiotic on tendons to prevent infections could be useful and safe for resident cells if used at a concentration of 2.5 mg/mL up to 1 hour of treatment.

The use of stem cells transplanted into the intervertebral disc (IVD) is a promising regenerative approach to treat intervertebral disc degeneration (IDD). The aim of this study was to assess the effect of a hydrogel composed of hyaluronic acid (HA) and platelet-rich plasma (PRP) loaded with human mesenchymal stem cells (hMSCs), on IVD extracellular matrix synthesis and nucleus pulposus (NP) marker expression in a whole IVD culture model.

HA was blended with batroxobin (BTX), a gelling agent activated in presence of PRP to construct a hydrogel. Bovine IVDs (n=25) were nucleotomised and filled with 1×10⁶ or 2×10⁶ hMSCs suspended in ∼150 mL of the PRP/HA/BTX hydrogel. IVDs harvested at day 0 and nucleotomised IVDs with no hMSCs and/or hydrogel were used as controls. hMSCs alone or encapsulated in the hydrogel were also cultured in well plates to examine the effect of the IVD microenvironment on hMSCs. After 1 week, tissue structure, scaffold integration and gene expression of anabolic (collagen type I, collagen type II and aggrecan), catabolic (matrix metalloproteinase 3 – MMP-3 –, MMP-13 and a disintegrin and metalloproteinase with thrombospondin motifs 4) and NP cell (cytokeratin 19, carbonic anhydrase 12, cluster of differentiation 24) markers were assessed.

Histological analysis showed a good integration of the scaffold within the NP area with cell repopulation. At the gene expression level, the hMSC-loaded hydrogels demonstrated to increase disc cell anabolic and catabolic marker expression and promoted hMSC differentiation towards a NP cell phenotype.

This study demonstrated that the HA/PRP/BTX may represent a valid carrier for hMSCs being capable of stimulating cell activity and NP marker expression as well as achieving a good integration with the surrounding tissues.

Objective: Meniscus regeneration is limited, moreover, loss of meniscal tissue leads to osteoarthritis. A new biomaterial, consisting of hyaluronic acid and polycaprolactone was applied as a meniscus substitute device in a study in sheep.

Methods: 24 sheep received a total medial meniscal replacement. Group SCF (n=12) was treated with a cell free scaffold, Group SCS (n=12) with a scaffold seeded with autologous chondrocytes harvested from the contralateral joints, which served as sham controls (n=12). Further 12 non-operated and 2 menisectomy controls were included in the study.

The animals were sacrificed after 4 months. The implants and joint surfaces were evaluated on a macroscopic (Implant Gross Assessment Score; Gross Assessment of Joints Score) and histological level.

Results: There was no significant difference of the Implant Gross Assessment score between the SCF and SCS groups. All implants showed excellent capsular ingrowth at the periphery. Dislocation, extrusion and tears occurred in part of the specimen due to biomechanical problems caused by soft tissue quality. The mean Gross Assessment of Joint Changes Score of the groups SCF and SCS was not statistically different. Cartilage damage was significantly more severe in joints with implants than in non-operated joints and sham controls, but less pronounced than in menisectomy controls. Histological evaluation showed residual scaffold with an associated foreign body response in all implants. Fibrous tissue was present in all implants, in contrast small foci of cartilaginous differentiation were more common in the cell-seeded constructs.

Discussion: At 4 months regenerative meniscal tissue was present but immature. The present study showed that strong biomechanical scaffold properties are a required to allow guided tissue regeneration and maturation under loading conditions. Cell seeding of the scaffold encourages cartilaginous differentiation. Modification of the scaffold and the cell-seeding technique will be investigated in further studies.

INTRODUCTION. A new class of soybean-based bio-materials has been presented to the scientific community (patent PCT/GB01/03464) which shows good mechanical properties and an intrinsic anti-inflammatory potential, probably related to the phyto-hormone Genistein. This plant isoflavone is also reported to inhibit osteo-clastic activity.

MATERIALS AND METHODS. De-fatted soybean curd was prepared into granules which were subsequently implanted in a cylindrical cavity drilled into the femural canal of New Zealand White rabbits. Retrieved femurs were embedded in poly-methyl-meta-acrylate and samples were analyzed by back-scattered electron microscopy (BSEM).

RESULTS. Retrieved operated femurs showed a macroscopic appearance similar to the non-operated controls. BSEM showed that granules were still present at the site of implantation after 8 weeks, but a clear progressive degradation took place from the periphery to the centre of the femural canal already after 3 weeks. The degradation of the granule was accompanied by the production of new trabeculae apposed to the surface of the material.

CONCLUSIONS. It can be hyothesised that the released Genistein shifts the metabolic balance towards bone production by inhibiting the macrophagic and osteo-clastic activities and that the material degrading surface supports the apposition and mineralization of the newly-formed bone.

A new class of soybean-based biomaterials has been presented to the scientific community (patent PCT/GB01/03464) that shows good mechanical properties and an intrinsic anti-inflammatory potential, probably related to the phyto-hormone Genistein. This plant iso-flavone is also reported to inhibit osteoclastic activity.

De-fatted soybean curd was prepared into granules which were subsequently implanted in a cylindrical cavity drilled into the femoral canal of New Zealand White rabbits. Retrieved femurs were embedded in polymethyl-meta-acrylate and samples were analysed by back-scattered electron microscopy (BSEM). Retrieved, operated femurs showed a macroscopic appearance similar to the non-operated controls. BSEM showed that granules were still present at the site of implantation after 8 weeks, but a clear progressive degradation took place from the periphery to the centre of the femural canal already after 3 weeks. The degradation of the granule was accompanied by the production of new trabeculae apposed to the surface of the material.

It can be hypothesised that the released Genistein shifts the metabolic balance towards bone production by inhibiting the macrophagic and osteoclastic activities and that the material degrading surface supports the apposition and mineralisation of the newly formed bone.

Coatings for endo-osseous implants have been developed based on phospholipids. Such coatings promote the formation of a very thin superficial rim which is highly enriched with calcium phosphates.

Two phospholipid-based preparations have been compared with a standard hydroxyapatite coating. Preparation S was based on phosphatidyl-serine; preparation C was based on a mixture of phosphatidyl-serine, phosphatidyl-choline and cholesterol. Titanium cylinders spammed with titanium foam were the metallic substrate for the coatings; they were implanted in the femoral canal of New Zealand White rabbits and retrieved after 4, 8 and 26 weeks. A back scattered electron microscopy analysis followed.

Both phospholipid preparations were shown not to have any inhibitory action on bone apposition and growth and did not elicit any adverse fibrous reaction. Pictures of bone in-growth into the cavities of the titanium foam are present. A truly tight apposition between bone and coating was evident only in the comparative group sprayed with hydroxyapatite, but this latter coating was often fragmented and its constituent granules were evident. The phospholipid-based coatings did not show inhibitory action on bone apposition and growth and did not elicit any adverse fibrous reaction.

Aims: A mounting research effort has recently been devoted to design a biocompatible, sterile and safe material as nucleus polposus substitute.

Several chemical modifications of Hyaluronic acid (HA), a biodegradable linear polysaccharide, have been devised to provide mechanically and chemically robust materials in medical applications.

This study was specially designed to assess whether such a kind of materials are capable to substitute natural NP by suitable viscoelastic properties.

Methods: The NPs were obtained from pigs (L4-L5, L6-L7). Bromide of 2-Hydroxy-4-hydroxyethoxy-2-methyl-propriophenone ester of HA (50% of degree of esterification, cross-linked gel) (HYAFF120p50A8) and dodecylic amide of Hyaluronic acid (11% of carboxyl group substitution of 200 kDa HA) (HYADD3A8) solutions, supplied by FAB, were studied at different ionic strength (0 and 0.15M).

Small amplitude oscillatory shear tests were performed to study linear viscoelastic properties by using a strain controlled rheometer (Bohlin VOR). In particular, the elastic modulus (G’) and the viscous modulus G’’ were evaluated.

Results: Porcine NP showed a rheological behaviour typical of “weak gel”. Indeed, G’ values were always higher than G” ones all over the frequency range and both moduli were almost frequency independent. In particular, at 1 Hz G’ and G” values were respectively 310 and 81 Pa.

The same rheological behaviour was observed for all HA derivatives. In particular, G’ and G’’ were respectively equal to 400 and 91Pa for HYADD3A8 solutions at 1Hz and at 20mg/ml (0,15M), and 210 and 51Pa for HYAFF120p50A8 at 50 mg/ml(0M).

Conclusions: HYADD3A8 and HYAFF120p50A8 solutions seem promising candidates as NP substitute from a viscoelastic point of view. In particular, HYADD3A8 (20mg/ml,0.15M solution) properly matched the rheological behaviour of porcine NPs.

Aims: A new class of soybean-based biomaterials has been presented (patent PCT/GB01/03464) which shows good mechanical properties and an intrinsic anti-inflammatory potential, probably related to the phyto-hormone Genistein. This plant isoflavone is also reported to inhibit osteoclastic activity. Aim of this study is to evaluate in-vivo the bone response to such soybean-based biomaterials.

Methods: De-fatted soybean curd was prepared into granules which were subsequently implanted in a cylindrical cavity drilled into the femural canal of New Zealand White rabbits. Retrieved femurs were embedded in poly-methyl-methacrylate and samples were analyzed by back-scattered electron microscopy (BSEM).

Results: Retrieved operated femurs showed a macroscopic appearance similar to the non-operated controls. BSEM showed that granules were still present at the site of implantation after 8 weeks, but a clear progressive degradation took place from the periphery to the centre of the femural canal already after 3 weeks. The degradation of the granule was accompanied by the production of new trabeculae apposed to the surface of the material.

Conclusions: It can be hypothesised that the released Genistein shifts the metabolic balance towards bone production by inhibiting the macrophagic and osteo-clastic activities and that the material degrading surface supports the apposition and mineralization of newly-formed bone.

Tissue engineering regards the generation, regeneration, augmentation or limitation of the structure and function of living tissues by the application of scientific and engineering principles. Skeletal defects resulting from tumor resection, congenital abnormalities or trauma often require surgical intervention to restore the function. Current option for bone replacement include autografts,allografts,metals,ceramic and polymers.However, all these materials have drawbacks, and their selection usually require some compromises.

Skeletal tissues are under extensive investigation in tissue engineering research and beside the biological issues, the scaffolds design plays an important role. A number of biodegradable and bioabsorbable materials as well as scaffold designs, have been experimentally and, in some cases clinically studied. An appropriate scaffold should posses highly porous with interconnected pore network for cell growth and flow transport of nutrient and metabolic waste; biocompatible and bioresorbable with a controlled degradation and resorption rate to match cell/ tissue growth, suitable surface chemistry for cell attachment, proliferation and differentiation, and mechanical properties to match those of the implanted tissue. Synthetic biodegradable polymers and inorganic materials are promising as extracellular matrix analogue to facilitated tissue development and growth; these include: polyglycolic acid, poly-l-lactic acid, copolymers, poly-caprolactones, hydroxyapatite, tricalcium phosphates. All these scaffolds are well performing from biological and chemical-physical but they have some limitations from mechanical point of view. To overcome this problem a composite structure made by Polycaprolactone and Hydroxyapatite is studied by mechanical and biological analysis. To obtain a porous structure, the casting and salt leaching technique is implemented. The composite shows mechanical properties in the range of the spongy bone and interesting biological properties with regards to osteoblasts.

Injectable gels made of collagen are analysed to carry cells, a preliminary results of collagen gel loaded with MSC cells have been performed and rheological and proliferation study are showing the feasibility to obtain a bioactive materials/cells to be inject in the defined body site defects avoiding massive surgery.

Aims. Coatings for endo-osseous implants have been developed based on phospholipids. Such coatings promote the formation of a very thin superficial layer which is highly enriched with calcium phosphates. Aim of this study is a comparison of such coatings with an hydroxyapatite coating.

Methods. Two phospholipid-based preparations have been compared with a standard hydroxyapatite coating. Preparation S was based on phosphatidyl-serine; preparation C was based on a mixture of phosphatidyl-serine, phosphatidyl-choline and cholesterol. Titanium cylinders wrapped with titanium foam were the metallic substrate for the coatings; they were implanted in the femural canal of New Zealand White rabbits and retrieved after 4, 8 and 26 weeks. A Back Scattered Electron Microscopy analysis followed.

Results. Both phospholipid preparations showed to have no inhibitory action on bone apposition and growth and did not elicit any adverse fibrous reaction. Pictures of bone in-growth into the cavities of the titanium foam were present. A tight apposition between bone and coating was evident only in the comparative group sprayed with hydroxyapatite, but this latter coating was often fragmented and its constituent granules were evident.

Conclusion. Phospholipid-based coatings showed no inhibitory action on bone apposition and growth and did not elicit any adverse fibrous reaction.

Aims: Both partial and total functional disorders of spine are one of the most disabling, common and costly problem of current surgery. The surgical treatment may involve the partial or total resection of the Intervertebral Disc (IVD). Thus, implants for vertebral fusion are often required in order to immobilize the diseased column.

Cage implants are designed in order to separate contiguous vertebrae allowing an adequate stress transfer and favoring bone growth. In this paper the biomechanical and histological properties of novel composite cages and commercial titanium implants have been in vitro and in vivo investigated.

Materials: Novel composite lumbar cages were designed by F.E.M., manufactured and implanted in porcine spine at the L4-L5 lumbar zone of five pigs (large white-duroc race of 50–55 Kg by weight and 1.9–2.1 months old). Each composite cage was prepared by filament winding technology by using PEI (PolyEtherImmide – GE Polymerland ULTEM 1000/1000) as matrix and Carbon fibre (Torayca T400-B 6000-50B) as reinforcement with a winding angle of 45A1 degree. Mechanical properties were investigated according to ASTM standard on composite material, novel composite cage, titanium cage and the natural disc. The device was coated with PEI – HA (hydroxyapatite) solution in order to improve the bone interaction. The behaviour of the composite cage was compared to titanium lumbar cages (SOFAMOR Danek) through biomechanical and histological tests.

Results: Tensile test performed on composite material have showed a Young’s Modulus equal to 40,1 GPa, maximum tensile strength equal to 602 MPa. Compressive test on the composite cage showed an Elastic Modulus value of 22 GPa. The comparison among the three systems displayed comparable compliance for titanium (0,0014mm/mm) and composite cage (0,0031mm/mm) while an higher compliance in the case of natural disc (0,0521mm/mm). All pigs showed good health up to the sacrificing date. Particularly, histological tests after two months from the implantation already showed abundant the presence of new-formed tissue around the composite cage.

Conclusions:. The results demonstrate that PEI reinforced with Carbon fibres composite cages coated with HA show excellent performance. Mechanical properties of the composite cages are closer to the properties of cortical bone than those of titanium cages, thus reducing the effect of stress concentration and stress shielding and as observed for stiff metal implants.