Croix C, Sowa G, Pola E, Robbins PD, Kang J, Niedernhofer LJ, Wipf P, Vo NV. Mitochondrial-derived reactive oxygen species (ROS) play a causal role in aging-related intervertebral disc degeneration

Oxidative damage is a well-established driver of aging. Evidence of oxidative stress exists in aged and degenerated discs, but it is unclear how it affects disc metabolism. In this study, we first determined whether oxidative stress negatively impacts disc matrix metabolism using disc organotypic and cell cultures. Mouse disc organotypic culture grown at atmospheric oxygen (20% O(2)) exhibited perturbed disc matrix homeostasis, including reduced proteoglycan synthesis and enhanced expression of matrix metalloproteinases, compared to discs grown at low oxygen levels (5% O(2)). Human disc cells grown at 20% O(2) showed increased levels of mitochondrial-derived superoxide anions and perturbed matrix homeostasis. Treatment of disc cells with the mitochondria-targeted reactive oxygen species (ROS) scavenger XJB-5-131 blunted the adverse effects caused by 20% O(2). Importantly, we demonstrated that treatment of accelerated aging Ercc1(-/Δ) mice, previously established to be a useful in vivo model to study age-related intervertebral disc degeneration (IDD), also resulted in improved disc total glycosaminoglycan content and proteoglycan synthesis. This demonstrates that mitochondrial-derived ROS contributes to age-associated IDD in Ercc1(-/Δ) mice. Collectively, these data provide strong experimental evidence that mitochondrial-derived ROS play a causal role in driving changes linked to aging-related IDD and a potentially important role for radical scavengers in preventing IDD.

Sonic hedgehog regulates angiogenesis and myogenesis during post-natal skeletal muscle regeneration

Sonic hedgehog (Shh) is a morphogen-regulating crucial epithelial-mesenchymal interactions during embryonic development, but its signalling pathway is considered generally silent in post-natal life. In this study, we demonstrate that Shh is de novo expressed after injury and during regeneration of the adult skeletal muscle. Shh expression is followed by significant up-regulation of its receptor and target gene Ptc1 in injured and regenerating muscles. The reactivation of the Shh signalling pathway has an important regulatory role on injury-induced angiogenesis, as inhibition of Shh function results in impaired up-regulation of prototypical angiogenic agents, such as vascular endothelial growth factor (VEGF) and stromal-derived factor (SDF)-1alpha, decreased muscle blood flow and reduced capillary density after injury. In addition, Shh reactivation plays a regulatory role on myogenesis, as its inhibition impairs the activation of the myogenic regulatory factors Myf-5 and MyoD, decreases the up-regulation of insulin-like growth factor (IGF)-1 and reduces the number of myogenic satellite cells at injured site. Finally, Shh inhibition results in muscle fibrosis, increased inflammatory reaction and compromised motor functional recovery after injury. These data demonstrate that the Shh pathway is functionally important for adult skeletal muscle regeneration and displays pleiotropic angiogenic and myogenic potentials in post-natal life. These findings might constitute the foundation for new therapeutic approaches for muscular diseases in humans.

Multidisciplinary management of pyogenic spondylodiscitis: epidemiological and clinical features, prognostic factors and long-term outcomes in 207 patients

PURPOSE

Pyogenic spondylodiscitis (PS) is a potentially life-threatening infection burdened by high morbidity rates. Despite the rising incidence, the proper management of PS is still controversial. Aim of this study was to describe the clinical features of PS and to evaluate the prognostic factors and the long-term outcomes of a large population of patients.

METHODS

207 cases of PS treated from 2008 to 2016 with a 2-year follow-up were enrolled. Clinical data from each patient were recorded. The primary outcome was the rate of healing without residual disability. Secondary outcomes included length of stay, healing from infection, death, relapse, and residual disability. Binomial logistic regression and multivariate analysis were used to evaluate prognostic factors.

RESULTS

Median diagnostic delay was 30 days and the rate of onset neurological impairment was 23.6%. Microbiological diagnosis was established in 155 patients (74.3%) and the median duration of total antibiotic therapy was 148 days. Orthopedic treatment was conservative for 124 patients and surgical in 47 cases. Complete healing without disability was achieved in 142 patients (77.6%). Statistically confirmed negative prognostic factors were: negative microbiological culture, neurologic impairment at diagnosis and underlying endocarditis (p ≤ 0.05). Healing from infection rate was 90.9%, while residual disabilities occurred in 23.5%. Observed mortality rate was 7.8%.

CONCLUSION

The microbiological diagnosis is the main predictive factor for successful treatment. Early diagnosis and multidisciplinary management are also needed to identify underlying aggressive conditions and to avoid neurological complications associated with poorer long-term outcomes. Despite high healing rates, PS may lead to major disabilities still representing a difficult challenge. These slides can be retrieved under Electronic Supplementary material.

New classification for the treatment of pyogenic spondylodiscitis: validation study on a population of 250 patients with a follow-up of 2 years

PURPOSE

Pyogenic spondylodiscitis (PS) is still burdened by a high rate of orthopedic and neurological complications. Despite the rising incidence, the choice of a proper orthopedic treatment is often delayed by the lack of clinical data. The aim of this study was to propose a clinical-radiological classification of pyogenic spondylodiscitis to define a standard treatment algorithm.

METHODS

Based on data from 250 patients treated from 2008 to 2015, a clinical-radiological classification of pyogenic spondylodiscitis was developed. According to primary classification criteria (bone destruction or segmental instability, epidural abscesses and neurological impairment), three main classes were identified. Subclasses were defined according to secondary criteria. PS without segmental instability or neurological impairment was treated conservatively. When significant bone loss or neurological impairment occurred, surgical stabilization and/or decompression were performed. All patients underwent clinical and radiological 2-year follow-up.

RESULTS

Type A PS occurred in 84 patients, while 46 cases were classified as type B and 120 as type C. Average time of hospitalization was 51.94 days and overall healing rate was 92.80%. 140 patients (56.00%) were treated conservatively with average time of immobilization of 218.17 ± 9.89 days. Both VAS and SF-12 scores improved across time points in all classes. Residual chronic back pain occurred in 27 patients (10.80%). Overall observed mortality was 4.80%.

CONCLUSIONS

Standardized treatment of PS is highly recommended to ensure patients a good quality of life. The proposed scheme includes all available orthopedic treatments and helps spine surgeons to significantly reduce complications and costs and to avoid overtreatment.

ATM is a key driver of NF-κB-dependent DNA-damage-induced senescence, stem cell dysfunction and aging

NF-κB is a transcription factor activated in response to inflammatory, genotoxic and oxidative stress and important for driving senescence and aging. Ataxia-telangiectasia mutated (ATM) kinase, a core component of DNA damage response signaling, activates NF-κB in response to genotoxic and oxidative stress via post-translational modifications. Here we demonstrate that ATM is activated in senescent cells in culture and murine tissues from Ercc1-deficient mouse models of accelerated aging, as well as naturally aged mice. Genetic and pharmacologic inhibition of ATM reduced activation of NF-κB and markers of senescence and the senescence-associated secretory phenotype (SASP) in senescent Ercc1-/- MEFs. Ercc1-/Δ mice heterozygous for Atm have reduced NF-κB activity and cellular senescence, improved function of muscle-derived stem/progenetor cells (MDSPCs) and extended healthspan with reduced age-related pathology especially age-related bone and intervertebral disc pathologies. In addition, treatment of Ercc1-/∆ mice with the ATM inhibitor KU-55933 suppressed markers of senescence and SASP. Taken together, these results demonstrate that the ATM kinase is a major mediator of DNA damage-induced, NF-κB-mediated cellular senescence, stem cell dysfunction and aging and thus represents a therapeutic target to slow the progression of aging.

The -174 G/C polymorphism of the interleukin-6 gene promoter is associated with peripheral artery occlusive disease

OBJECTIVE AND DESIGN

high plasma levels of Interleukin-6 (IL-6) are found in patients with atherosclerotic disorders. Recently, a common polymorphism of the IL-6 gene promoter, influencing the transcription rate of the gene, has been described and associated with atherosclerosis of carotid and coronary arteries. The objective of this study was to test whether IL-6 gene promoter polymorphism is associated with peripheral artery occlusive disease (PAOD) in a case-control study.

METHODS

IL-6 gene promoter polymorphism was evaluated by polymerase chain reaction followed by restriction enzyme analysis in 84 patients affected by PAOD and 183 controls.

RESULTS

the distribution of IL-6 genotypes was: patients with PAOD: 44 GG, 30 GC, 10 CC; control subjects: 53 GG, 80 GC, 50 CC. The GG genotype was significantly more common in the PAOD group (p<0.0001), while the CC genotype was significantly more common in control patients (p=0.005).

CONCLUSIONS

this study indicates a strong association between IL-6 gene polymorphism and PAOD and support the hypothesis that IL-6 and IL-6 gene polymorphism are important in the pathophysiology and evolution of ischaemic diseases of the lower limbs.

ISSLS prize winner: inhibition of NF-κB activity ameliorates age-associated disc degeneration in a mouse model of accelerated aging

STUDY DESIGN

NF-κB activity was pharmacologically and genetically blocked in an accelerated aging mouse model to mitigate age-related disc degenerative changes.

OBJECTIVE

To study the mediatory role of NF-κB-signaling pathway in age-dependent intervertebral disc degeneration.

SUMMARY OF BACKGROUND DATA

Aging is a major contributor to intervertebral disc degeneration (IDD), but the molecular mechanism behind this process is poorly understood. NF-κB is a family of transcription factors that play a central role in mediating cellular response to damage, stress, and inflammation. Growing evidence implicates chronic NF-κB activation as a culprit in many aging-related diseases, but its role in aging-related IDD has not been adequately explored. We studied the effects of NF-κB inhibition on IDD, using a DNA repair-deficient mouse model of accelerated aging (Ercc1 mice) previously been reported to exhibit age-related IDD.

METHODS

Systemic inhibition of NF-κB activation was achieved either genetically by deletion of 1 allele of the NF-κB subunit p65 (Ercc1p65 mice) or pharmacologically by chronic intraperitoneal administration of the Nemo Binding Domain (8K-NBD) peptide to block the formation of the upstream activator of NF-κB, IκB Inducible Kinase (IKK), in Ercc1 mice. Disc cellularity, total proteoglycan content and proteoglycan synthesis of treated mice, and untreated controls were assessed. RESULTS.: Decreased disc matrix proteoglycan content, a hallmark feature of IDD, and elevated disc NF-κB activity were observed in discs of progeroid Ercc1 mice and naturally aged wild-type mice compared with young wild-type mice. Systemic inhibition of NF-κB by the 8K-NBD peptide in Ercc1 mice increased disc proteoglycan synthesis and ameriolated loss of disc cellularity and matrix proteoglycan. These results were confirmed genetically by using the p65 haploinsufficient Ercc1p65 mice.

CONCLUSION

These findings demonstrate that the IKK/NF-κB signaling pathway is a key mediator of age-dependent IDD and represents a therapeutic target for mitigating disc degenerative diseases associated with aging.

Is posterior percutaneous screw-rod instrumentation a safe and effective alternative approach to TLSO rigid bracing for single-level pyogenic spondylodiscitis? Results of a retrospective cohort analysis

BACKGROUND CONTEXT

Currently, treatment for patients diagnosed with noncomplicated (ie, known infectious agent, no neurologic compromise, and preserved spinal stability) pyogenic spondylodiscitis (PS) is based on intravenous antibiotics and rigid brace immobilization. Since January 2010, we started offering our patients percutaneous posterior screw-rod instrumentation as an alternative approach to rigid bracing. Supposed benefits of posterior percutaneous instrumentation over rigid bracing are earlier free mobilization, increased comfort, and faster recovery.

PURPOSE

To evaluate safety and effectiveness of posterior percutaneous spinal instrumentation for single-level PS and compare clinical and quality-of-life outcomes with standard thoracolumbosacral orthosis (TLSO) rigid bracing.

STUDY DESIGN/SETTING

Retrospective observational cohort study.

PATIENT SAMPLE

Twenty-seven patients consecutively diagnosed with single-level noncomplicated lower thoracic or lumbar PS from January 2010 to December 2011.

OUTCOME MEASURES

Healing rate, healing time, and changes in segmental kyphosis Cobb angle were compared in the two treatment groups. Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and complete blood count at regular time points until complete healing were also obtained. Self-report measures included Visual Analog Scale (VAS), Short-Form 12 (SF-12), and EuroQol five-dimension (EQ-5D) questionnaires.

METHODS

At enrollment, patients were offered to choose between 24/7 TLSO rigid bracing for 3 to 4 months and bridging posterior percutaneous screw-rod instrumentation followed by soft bracing for 4 weeks after surgery. All patients underwent antibiotic therapy accordingly to isolated infectious agents. Patients were seen in the clinic at 1, 3, 6, and 9 months, and ESR, CRP, complete blood count, VAS, SF-12, and EQ-5D questionnaires were obtained. Segmental kyphosis was measured at diagnosis and at 9 months follow-up. Two-way repeated-measures analysis of variance was used to assess group and time differences across time points.

RESULTS

Fifteen patients chose conservative treatment, whereas 12 patients chose surgical treatment. Complete infection healing was achieved in all patients with no significant differences in healing time (p<.366). C-reactive protein and ESR levels decreased in both groups accordingly with positive response to therapy with no significant differences. Surgically treated patients had significantly lower VAS scores at 1 month (2.76±0.80 vs. 5.20±1.21, p<.001) and 3 months (2.31±0.54 vs. 2.85±0.54, p<.016) post-diagnosis over TLSO patients. Moreover, surgery patients also showed steeper and statistically significant improvements in SF-12 scores over TLSO patients at 1, 3, and 6 months post-diagnosis (p<.012); no significant differences were detected at the other time points. EuroQol five-dimension index was significantly higher in surgery patients at 1 month (0.764±0.043 vs. 0.458±0.197, p<.001) and 3 months (0.890±0.116 vs. 0.688±0.142, p<.001); no significant changes were observed in segmental pre- and posttreatment kyphosis between the two groups. No instrumentation-related complications were observed in any patient.

CONCLUSIONS

Posterior percutaneous spinal instrumentation is a safe, feasible, and effective procedure in relieving pain, preventing deformity, and neurologic compromise in patients affected by noncomplicated lower thoracic (T9-T12) or lumbar PS. Posterior instrumentation did not offer any advantage in healing time over TLSO rigid bracing because infection clearance is strongly dependent on proper antibiotic therapy. Nevertheless, surgical stabilization was associated with faster recovery, lower pain scores, and improved quality of life compared with TLSO conservative treatment at 1, 3, and 6 months after treatment.

Investigating the role of DNA damage in tobacco smoking-induced spine degeneration

BACKGROUND CONTEXT

Tobacco smoking is a key risk factor for spine degeneration. However, the underlying mechanism by which smoking induces degeneration is not known. Recent studies implicate DNA damage as a cause of spine and intervertebral disc degeneration. Because tobacco smoke contains many genotoxins, we hypothesized that tobacco smoking promotes spine degeneration by inducing cellular DNA damage.

PURPOSE

To determine if DNA damage plays a causal role in smoking-induced spine degeneration.

STUDY DESIGN

To compare the effect of chronic tobacco smoke inhalation on intervertebral disc and vertebral bone in normal and DNA repair-deficient mice to determine the contribution of DNA damage to degenerative changes.

METHODS

Two-month-old wild-type (C57BL/6) and DNA repair-deficient Ercc1(-/Δ) mice were exposed to tobacco smoke by direct inhalation (4 cigarettes/day, 5 days/week for 7 weeks) to model first-hand smoking in humans. Total disc proteoglycan (PG) content (1,9-dimethylmethylene blue assay), PG synthesis ((35)S-sulfate incorporation assay), aggrecan proteolysis (immunoblotting analysis), and vertebral bone morphology (microcomputed tomography) were measured.

RESULTS

Exposure of wild-type mice to tobacco smoke led to a 19% increase in vertebral porosity and a 61% decrease in trabecular bone volume. Intervertebral discs of smoke-exposed animals also showed a 2.6-fold decrease in GAG content and an 8.1-fold decrease in new PG synthesis. These smoking-induced degenerative changes were similar but not worse in Ercc1(-/Δ) mice.

CONCLUSIONS

Short-term exposure to high levels of primary tobacco smoke inhalation promotes degeneration of vertebral bone and discs. Disc degeneration is primarily driven by reduced synthesis of proteoglycans needed for vertebral cushioning. Degeneration was not exacerbated in congenic DNA repair-deficient mice, indicating that DNA damage per se does not have a significant causal role in driving smoke-induced spine degeneration.

Association between IL-6 and MMP-3 gene polymorphisms and adolescent idiopathic scoliosis: a case-control study

STUDY DESIGN

Case-control study.

OBJECTIVE

As inflammation plays a key role in the etiology of intervertebral disc degeneration, we suggest a possible contribution of pro-inflammatory gene polymorphisms in the pathogenesis of adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

The nucleus pulposus of scoliotic discs responds to exogenous stimuli by secreting interleukin-6 (IL-6) and other inflammatory cytokines. The association between matrix metalloproteinases (MMPs) and disc degeneration has been reported by several investigators. A human MMP-3 promoter 5A/6A gene polymorphism regulates MMP-3 genes expression, while the G/C polymorphism of the promoter region of IL-6 gene influences levels and functional activity of the IL-6 protein.

METHODS

We conducted a case-control study to investigate whether the 5A/6A polymorphism of the MMP-3 gene and the G/C polymorphism of the promoter region of IL-6 gene were associated with susceptibility to AIS.

RESULTS

The frequency of the 5A/5A genotype of MMP-3 gene polymorphism in patients with scoliosis was almost 3 times higher than in controls (30.2% vs. 11.2%, p 0.001), and the frequency of the G/G genotype of IL-6 gene polymorphism in patients with scoliosis was almost 2 times higher than in controls (52.8% vs. 26.2%, P < 0.001). 5A/5A genotype of MMP-3 gene polymorphism and G/G genotype of IL-6 gene polymorphism are independently associated with a higher risk of scoliosis (odds ratio, respectively, 3.34 and 10.54).

CONCLUSION

This is the first study that has evaluated the possibility that gene variants of IL-6 and MMPs might be associated with scoliosis and suggests that MMP-3 and IL-6 promoter polymorphisms constitute important factors for the genetic predisposition to scoliosis.

Clinical factors associated with an increased risk of perioperative blood transfusion in nonanemic patients undergoing total hip arthroplasty

BACKGROUND

The aim of this study was to identify clinical factors associated with an increased need for perioperative blood transfusion in nonanemic patients undergoing total hip arthroplasty.

METHODS

We evaluated eighty-five consecutive nonanemic patients who underwent elective, unilateral, cementless, primary total hip arthroplasty and met our inclusion criteria. We attempted to determine whether clinical parameters influencing perioperative blood loss, such as age, gender, hypertension, and body mass index, were also associated with the need for perioperative blood transfusion.

RESULTS

Perioperative blood transfusion was required in twenty-four (28%) of the eighty-five nonanemic patients. When considered alone, age, gender, hypertension, and body mass index were not significantly associated with an increased risk of perioperative blood transfusion, on the basis of the numbers available. In contrast, there was a significantly increased risk of blood transfusion when two or more of these clinical parameters were present (p = 0.02).

CONCLUSIONS

Our findings indicate that clinical variables such as age, gender, hypertension, and body mass index may have a synergistic effect on the risk of transfusion in patients undergoing elective total hip arthroplasty. The simultaneous analysis of these parameters might help to stratify patients with different risks for transfusion and may increase the efficiency and reduce the cost of blood-ordering practices associated with total hip arthroplasty.

LEVEL OF EVIDENCE

Prognostic study, Level II-1 (retrospective study). See Instructions to Authors for a complete description of levels of evidence.

Spondylolysis and spondylolisthesis in the pediatric and adolescent population

This article is a review of spondylolysis and spondylolisthesis in younger age groups. Since Herbinaux first described the pathology (1782), many classifications and theories of etiopathogenesis have been proposed. The congenital and isthmic types, as classified by Wiltse, are the most frequent in younger age groups, but the postsurgical progressive forms (3-5%) have been described as increasing in frequency secondary to neoplastic surgery in children. The general incidence is 4-5% at the age of 6 years, and in 30-50% of cases these types do not progress to spondylolisthesis. Most cases are asymptomatic (80%). Standard radiographic examinations (A-P, L, Oblique) are helpful in diagnosis and can suggest what the prognosis will be in terms of the evolution, and also what treatment is indicated (degree of slippage, slip angle, lumbar and lumbosacral index, SPTI). A bone scan (PBS and SPECT) is useful in the early stages of spondylolysis (pre-spondylosis). Although the CT scan is the most accurate examination, MRI is becoming important for diagnosis because of the frequency with which it is used as a primary investigation method. Depending on patient age, progression, degree of slippage, and symptoms, different therapeutic approaches have been proposed and are described in this paper.

The K469E polymorphism of the ICAM-1 gene is a risk factor for peripheral arterial occlusive disease

Intercellular adhesion molecule-1 (ICAM-1) plays a crucial role in lymphocyte migration and activation, and is considered important in the pathogenesis of atherosclerosis. K469E is a common polymorphism of the ICAM-1 gene with potential functional significance. The aim of the present case-control study was to evaluate the association between this polymorphism and peripheral arterial occlusive disease (PAOD). ICAM-1 gene polymorphism was examined by polymerase chain reaction and restriction enzyme analysis in 75 Italian subjects affected by PAOD and 227 controls. The distribution of ICAM-1 genotypes in patients affected by PAOD was 32.1% EE, 50.6% EK, and 17.3% KK. The distribution of ICAM-1 genotypes in control subjects was 17.2% EE, 55.1% EK, and 27.7% KK. The EE genotype was significantly more common in patients than controls (P = 0.006). Logistic regression analysis indicated that the presence of the EE genotype significantly increases the risk of PAOD (odds ratio, 3.5; 95% confidence interval, 1.5-8.4; P = 0.004). This is the first study documenting a role of the ICAM-1 gene polymorphism in the pathogenesis of a cardiovascular disease, such as PAOD. Our data support the hypothesis that inflammatory mechanisms are important in the pathophysiology of vascular diseases with an atherosclerotic basis.

Genotoxic stress accelerates age-associated degenerative changes in intervertebral discs

Intervertebral disc degeneration (IDD) is the leading cause of debilitating spinal disorders such as chronic lower back pain. Aging is the greatest risk factor for IDD. Previously, we demonstrated IDD in a murine model of a progeroid syndrome caused by reduced expression of a key DNA repair enzyme. This led us to hypothesize that DNA damage promotes IDD. To test our hypothesis, we chronically exposed adult wild-type (Wt) and DNA repair-deficient Ercc1(-/Δ) mice to the cancer therapeutic agent mechlorethamine (MEC) or ionization radiation (IR) to induce DNA damage and measured the impact on disc structure. Proteoglycan, a major structural matrix constituent of the disc, was reduced 3-5× in the discs of MEC- and IR-exposed animals compared to untreated controls. Expression of the protease ADAMTS4 and aggrecan proteolytic fragments was significantly increased. Additionally, new PG synthesis was reduced 2-3× in MEC- and IR-treated discs compared to untreated controls. Both cellular senescence and apoptosis were increased in discs of treated animals. The effects were more severe in the DNA repair-deficient Ercc1(-/Δ) mice than in Wt littermates. Local irradiation of the vertebra in Wt mice elicited a similar reduction in PG. These data demonstrate that genotoxic stress drives degenerative changes associated with IDD.

Ex vivo-transduced autologous skin fibroblasts expressing human Lim mineralization protein-3 efficiently form new bone in animal models

Local gene transfer of the human Lim mineralization protein (LMP), a novel intracellular positive regulator of the osteoblast differentiation program, can induce efficient bone formation in rodents. To develop a clinically relevant gene therapy approach to facilitate bone healing, we have used primary dermal fibroblasts transduced ex vivo with Ad.LMP-3 and seeded on a hydroxyapatite/collagen matrix prior to autologous implantation. Here, we demonstrate that genetically modified autologous dermal fibroblasts expressing Ad.LMP-3 are able to induce ectopic bone formation following implantation of the matrix into mouse triceps and paravertebral muscles. Moreover, implantation of the Ad.LMP-3-modified dermal fibroblasts into a rat mandibular bone critical size defect model results in efficient healing, as determined by X-rays, histology and three-dimensional microcomputed tomography (3DmuCT). These results demonstrate the effectiveness of the non-secreted intracellular osteogenic factor LMP-3 in inducing bone formation in vivo. Moreover, the utilization of autologous dermal fibroblasts implanted on a biomaterial represents a promising approach for possible future clinical applications aimed at inducing new bone formation.

Interleukin-6 gene polymorphism and risk of osteoarthritis of the hip: a case-control study

OBJECTIVES

Osteoarthritis (OA) is considered a polygenic disease controlled by the expression of genetic factors. Genes encoding for cytokines have been associated with susceptibility for joint OA and interleukin (IL)-6 gene is also supposed to be involved in the cartilage degradation process. In this case-control study, we evaluated for the first time whether the risk of hip OA might be influenced by the -174 IL-6 gene polymorphism.

METHODS

The distribution of IL-6 genotypes was evaluated in 75 patients affected by hip OA and in 107 age- and sex-matched controls.

RESULTS

The distribution of IL-6 genotypes in (1) patients with hip OA: 33 GG, 30 GC, 12 CC and (2) control subjects: 34 GG, 40 GC, 33 CC. The frequency of the CC genotype was significantly higher in control patients (P=0.02). Logistic regression analysis indicated that the presence of the CC genotype is independently associated with a decreased risk of OA (odds ratio 0.4 [95% confidence interval 0.1-0.9], P=0.04).

CONCLUSIONS

Primary OA of the hip has an important genetic component and variations of genes encoding for inflammatory cytokines, such as IL-6, may play an important role in the series of events responsible for the pathophysiology of OA.

Local infusion of norepinephrine reduces blood losses and need of transfusion in total knee arthroplasty

Blood loss after total knee arthroplasty (TKA) is often associated with cardiovascular complications and a high transfusion rate of allogenic blood. In our study we focused our attention on developing a new intra-surgical procedure that appears safe, easy to perform and effective in the reduction of bleeding in TKA. We evaluated 84 patients who underwent TKA and met our inclusion criteria; they were assigned to two groups: 55 controls in which a saline solution was used to wash the surgical field before tourniquet release, and a second group of 29 patients, in which a saline solution containing a low dose of norepinephrine was locally applied before tourniquet release. The local administration of a low dose of norepinephrine has induced a significant reduction of perioperative blood loss and blood transfusion requirements; in addition, this method was characterised by the absence of complications or adverse effects. In conclusion, our data suggest that intraoperative local administration of a low dose of norepinephrine could represent an effective and safe method of reducing blood loss and preventing blood transfusions in patients with TKA.

Efficient bone formation by gene transfer of human LIM mineralization protein-3

LIM mineralization protein (LMP) is a novel positive regulator of the osteoblast differentiation program. In humans, three different LMP splice variants have been identified: LMP-1, LMP-2, and LMP-3. Gene transfer of human LMP-1 (hLMP-1) induces expression of genes involved in bone formation, including certain bone morphogenetic proteins (BMPs), promotes bone nodule formation in vitro, ectopic bone formation in vivo, and is therapeutic in animal models of posterior thoracic and lumbar spine fusion. To examine the osteoinductive properties of the LMP-3 in vitro and in vivo, we have generated plasmid and adenoviral vectors expressing codon-optimized hLMP-3. Here we demonstrate that gene transfer of hLMP-3 induces expression of the bone-specific genes osteocalcin, osteopontin, and bone sialoprotein and induced bone mineralization in preosteoblastic and fibroblastic cells. We also demonstrate that hLMP-3 is able to induce bone mineralization and the expression of the bone-specific genes, BMP-2, OSX, RunX2, and alkaline phosphatase in human mesenchymal stem cells in a dose-dependent manner. Finally, we demonstrate that direct gene transfer of hLMP-3 into murine skeletal muscle results in ectopic bone formation more efficiently than BMP-2. These results demonstrate that hLMP-3 gene transfer can be used to promote bone formation in cell culture and in vivo as or more efficiently than BMP-2, thus establishing feasibility and efficacy of direct gene delivery of hLMP-3 to produce bone in vivo. These results suggest that gene transfer of hLMP-3 could be developed as a bone-inductive therapeutic agent for clinical applications.

Undifferentiated human adipose tissue-derived stromal cells induce mandibular bone healing in rats

OBJECTIVE

To test the osteo-regenerative potential of adipose tissue-derived stromal cells (ATSCs), an attractive human source for tissue engineering, in a rat model of mandibular defect. Human dermal fibroblasts (HDFs) were used as a differentiated cellular control in the study.

DESIGN

The ATSCs and HDFs were isolated from human lipoaspirate and skin biopsy specimens, respectively. Cells were characterized in vitro and then adsorbed on an osteo-conductive scaffold to be transplanted in a mandibular defect of immunosuppressed rats. Naked unseeded scaffold was used as a negative control.

MAIN OUTCOME MEASURES

Bone healing was studied by computerized tomography and histologic analysis after 4, 8, and 12 weeks.

RESULTS

Computed tomography showed that undifferentiated ATSCs induced successful bone healing of the mandible defect when transplanted in animals, compared with HDFs and negative controls. Histologic analysis demonstrated that the newly formed tissue in the surgical defect retained the features of compact bone.

CONCLUSION

Undifferentiated human ATSCs are suitable for cell-based treatment of mandibular defects, even in the absence of previous osteogenic induction in vitro.

Combined therapy with sonic hedgehog gene transfer and bone marrow-derived endothelial progenitor cells enhances angiogenesis and myogenesis in the ischemic skeletal muscle

We have previously demonstrated that sonic hedgehog (Shh) gene transfer improves angiogenesis in the setting of ischemia by upregulating the expression of multiple growth factors and enhancing the incorporation of endogenous bone marrow (BM)-derived endothelial progenitor cells (EPCs). In this study, we hypothesized that combined therapy with Shh gene transfer and BM-derived EPCs is more effective than Shh gene therapy alone in an experimental model of peripheral limb ischemia. We used old mice, which have a significantly reduced angiogenic response to ischemia, and compared the ability of Shh gene transfer, exogenous EPCs, or both to improve regeneration after ischemia. We found a significantly higher capillary density in the Shh + EPC-treated muscles compared to the other experimental groups. We also found that Shh gene transfer increases the incorporation and survival of transplanted EPCs. Finally, we found a significantly higher number of regenerating myofibers in the ischemic muscles of mice receiving combined treatment with Shh and BM-derived EPCs. In summary, the combination of Shh gene transfer and BM-derived EPCs more effectively promotes angiogenesis and muscle regeneration than each treatment individually and merits further investigation for its potential beneficial effects in ischemic diseases.

A minimally invasive posterior lumbar interbody fusion for degenerative lumbar spine instabilities

Percutaneous techniques may be helpful to reduce approach-related morbidity of conventional open surgery. The aim of the study was to evaluate the feasibility and safety of mini-open posterior lumbar interbody fusion for instabilities and degenerative disc diseases. From May 2005 until October 2008, 20 patients affected by monosegmental instability and disc herniation underwent mini-open lumbar interbody fusion combined with percutaneous pedicle screw fixation of the lumbar spine. Clinical outcome was assessed using the Visual Analog Scale, Oswestry Disability Index, and Short Form Health Survey-36. The mean follow-up was 24 months. The mean estimated blood loss was 126 ml; the mean length of stay was 5.3 days; the mean operative time was 171 min. At 24-month follow-up, the mean VAS score was 2.1, mean ODI was 27.1%, and mean SF-36 was 85.2%. 80 screws were implanted in 20 patients. 74 screws showed very good position, 5 screws acceptable, and 1 screw unacceptable. A solid fusion was achieved in 17 patients (85%). In our opinion, mini-open TLIF is a valid and safe treatment of lumbar instability and degenerative disc diseases in order to obtain faster return to daily activities.

Allergy in total knee replacement surgery: Is it a real problem?

Total knee arthroplasty is a common procedure, with extremely good clinical results. Despite this success, it produces 20% unsatisfactory results. Among the causes of these failures is metal hypersensitivity. Metal sensitization is higher in patients with a knee arthroplasty than in the general population and is even higher in patients undergoing revision surgery. However, a clear correlation between metal sensitization and symptomatic knee after surgery has not been ascertained. Surely, patients with a clear history of metal allergy must be carefully examined through dermatological and laboratory testing before surgery. There is no globally accepted diagnostic algorithm or laboratory test to diagnose metal hypersensitivity or metal reactions. The patch test is the most common test to determine metal hypersensitivity, though presenting some limitations. Several laboratory assays have been developed, with a higher sensitivity compared to patch testing, yet their clinical availability is not widespread, due to high costs and technical complexity. Symptoms of a reaction to metal implants present across a wide spectrum, ranging from pain and cutaneous dermatitis to aseptic loosening of the arthroplasty. However, although cutaneous and systemic hypersensitivity reactions to metals have arisen, thereby increasing concern after joint arthroplasties, allergies against implant materials remain quite rare and not a well-known problem. The aim of the following paper is to provide an overview on diagnosis and management of metal hypersensitivity in patients who undergo a total knee arthroplasty in order clarify its real importance.

GH receptor isoforms and skeletal fragility in acromegaly

OBJECTIVE

Acromegaly is associated with an increased prevalence of vertebral fractures (VFs) in close relationship with GH hypersecretion. Two isoforms of the GH receptor (GHR) have been identified; the two isoforms differ or not by the expression of the protein fragment encoded by exon 3 of the GHR gene. Deletion of the exon 3 may influence the functional properties of the GHR and affect fracture risk in acromegalic patients.

DESIGN

A cross-sectional study was designed to investigate the association between the d3-GHR isoform and the prevalence of VFs in patients with acromegaly.

METHODS

In this study, 109 acromegalic patients were included (M/F, 48/61): 73 with controlled/cured acromegaly and 36 with active disease. GHR genotype was assessed in each patient. All patients were evaluated for VFs and bone mineral density at lumbar spine and hip. Serum IGF1 levels and bone metabolism markers were measured. A multivariate analysis was performed to establish risk factors for VFs in our population.

RESULTS

d3-GHR carriers showed an increased prevalence of VFs when compared with patients expressing full-length GHR (35/55 vs 12/54; P<0.001). The association between GHR deletion and VFs was demonstrated both in patients with active disease and in those with controlled/cured disease. Out of 35 patients who were prospectively evaluated, 13 (37.1%) developed incident VFs. The incidence of VFs was significantly higher in patients for whom the GHR gene has been deleted when compared with those harboring the fl gene (P=0.04). In multivariate analysis, male sex (odds ratio (OR), 3.250; P=0.041), IGF1 levels (OR, 1.183; P=0.031), length of active diseases (OR, 1.038; P=0.001), and d3-GHR genotype (OR, 3.060; P=0.015) were all confirmed as risk factors of VFs in our population.

CONCLUSIONS

This study suggests for the first time that exon 3 deletion of GHR may predispose patients with active and controlled acromegaly to a higher risk of VFs.

A meta-analysis of interleukin-6 promoter polymorphisms on risk of hip and knee osteoarthritis

OBJECTIVE

Interleukin-6 is a pro-inflammatory cytokine involved in the pathogenesis of osteoarthritis (OA). We investigated the role of two single nucleotide polymorphisms (SNPs) mapping to the promoter of the IL-6 gene on genetic susceptibility to hip and knee OA.

METHODS

The -174G/C (rs1800795) and -597G/A (rs1800797) SNPs, implicated in the literature in risk of hip and hand OA, were genotyped in 2511 controls, 1101 hip OA cases and 1904 knee OA cases from four cohorts from the UK and Estonia. Data were analysed in conjuntion with published data on rs1800797 from the Genetics of OA and Lifestyle study (UK) on 791 controls, 1034 knee and 997 hip OA cases and rs1800795 data on 75 hip OA cases and 96 controls from Italy. Cases included both radiographic OA only and radiographic and symptomatic OA. Fixed and random-effects meta-analysis models were tested.

RESULTS

No significant association was found with hip OA or knee OA with either SNP nor with the haplotypes formed by them. For individual SNPs the smallest P-value for hip OA was observed using a random-effects model for rs1800795 OR(Gallele)=1.066 (95% CI 0.89-1.28) P<0.49, and significant heterogeneity between cohorts (I(2)=65%, P<0.034) was detected. For knee OA the smallest P-value was seen for rs1800797 OR(Aallele)=1.055 (95%CI 0.98-1.12) P<0.18, no significant heterogeneity was observed (I(2)=0%, P<0.68).

CONCLUSIONS

Our data do not support a role for the -174 and -597 IL-6 promoter polymorphisms in genetic susceptibility to knee or hip OA in Caucasian populations.

Sonic hedgehog therapy in a mouse model of age-associated impairment of skeletal muscle regeneration

Sonic hedgehog (Shh) is a morphogen regulating muscle development during embryogenesis. We have shown that the Shh pathway is postnatally recapitulated after injury and during regeneration of the adult skeletal muscle and regulates angiogenesis and myogenesis after muscle injury. Here, we demonstrate that in 18-month-old mice, there is a significant impairment of the upregulation of the Shh pathway that physiologically occurs in the young skeletal muscle after injury. Such impairment is even more pronounced in 24-month-old mice. In old animals, intramuscular therapy with a plasmid encoding the human Shh gene increases the regenerative capacities of the injured muscle, in terms of Myf5-positive cells, regenerating myofibers, and fibrosis. At the molecular level, Shh treatment increases the upregulation of the prototypical growth factors, insulin-like growth factor-1 and vascular endothelial growth factor. These data demonstrate that Shh increases regeneration after injury in the muscle of 24-month-old mice and suggest that the manipulation of the Shh pathway may be useful for the treatment of muscular diseases associated with aging.