Alterations in intervertebral disc composition, matrix homeostasis and biomechanical behavior in the UCD-T2DM rat model of type 2 diabetes

Type 2 diabetes (T2D) adversely affects many tissues, and the greater incidence of discogenic low back pain among diabetic patients suggests that the intervertebral disc is affected too. Using a rat model of polygenic obese T2D, we demonstrate that diabetes compromises several aspects of disc composition, matrix homeostasis, and biomechanical behavior. Coccygeal motion segments were harvested from 6-month-old lean Sprague-Dawley rats, obese Sprague-Dawley rats, and diabetic obese UCD-T2DM rats (diabetic for 69 ± 7 days). Findings indicated that diabetes but not obesity reduced disc glycosaminoglycan and water contents, and these degenerative changes correlated with increased vertebral endplate thickness and decreased endplate porosity, and with higher levels of the advanced glycation end-product (AGE) pentosidine. Consistent with their diminished glycosaminoglycan and water contents and their higher AGE levels, discs from diabetic rats were stiffer and exhibited less creep when compressed. At the matrix level, elevated expression of hypoxia-inducible genes and catabolic markers in the discs from diabetic rats coincided with increased oxidative stress and greater interactions between AGEs and one of their receptors (RAGE). Taken together, these findings indicate that endplate sclerosis, increased oxidative stress, and AGE/RAGE-mediated interactions could be important factors for explaining the greater incidence of disc pathology in T2D.

Efficiency of tranexamic acid in perioperative blood loss in hip arthroplasty: a systematic literature review and meta-analysis

INTRODUCTION AND OBJECTIVE

Tranexamic acid (TXA) is an antifibrinolytic drug used to reduce bleeding in mortality risk situations such as trauma. Our objective was to conduct a systematic literature review to evaluate the effectiveness and safety of TXA in reducing bleeding in hip arthroplasty.

MATERIAL AND METHODS

A systematic literature review and meta-analysis of primary studies similar to controlled trials was performed. Literature was searched in MEDLINE, Embase, Cochrane, LILACS, SciELO and Google Scholar. The review was proposed and undertaken by 2 reviewers and the inclusion criteria were: a) patients undergoing arthroplasty for primary unilateral hip replacement; b) comparison of a treatment group with TXA to a control group that received a placebo or no treatment at all, and c) outcome measures, total blood loss, number of patients receiving allogeneic transfusion and/or incidence of thromboembolic complications. The search was restricted to studies published from 1966 to June 2013.

RESULTS

A total of 16 studies with 246 patients were retrieved for this review. The total blood loss outcome evidenced a weighted mean difference in favor of TXA vs. controls undergoing hip arthroplasty (-0.45 [P<0.001, 95% CI -0.65 to -0.24]). Weighted relative risk was estimated for the allogeneic transfusion requirement outcome, showing a trend in favor the TXA arm, with fewer patients requiring allogeneic transfusion in hip surgery (0.8 [P<0.02, 95% CI 0.57 to 1.11]); however, this trend was not statistically significant.

LIMITATIONS

There is a noticeable difference in methods for quantifying total blood loss across the studies reviewed. The need for transfusion outcomes are probably not significant taking into account the number of events in the TXA group.

CONCLUSIONS

TXA can be routinely used to reduce intra- and post-operative blood loss in primary hip arthroplasty.

Safety of instrumentation and fusion at the time of surgical debridement for spinal infection

The present study aims to assess the results of single-stage instrumentation and fusion at the time of surgical debridement of spinal infections; vertebral osteomyelitis or epidural abscess. Nine patients with spinal infection were treated with instrumentation and fusion after radical debridement in a single-stage operation. Predisposing factors and comorbidities, pain, American Spinal Injury Association motor scores, primary pathologies, microbiology and perioperative markers were recorded. Seven patients with pyogenic and two with tuberculous spinal infection were encountered; the most common pathogen was Staphylococcus aureus. Five patients were predisposed to infection because of diabetes mellitus. Duration of antibiotic therapy lasted up to 12 months. Six patients had thoracic infection, two lumbar and one cervical. No post-operative complications were encountered. There was a significant reduction in pain scores compared to pre-operatively. All patients with neurological deficits improved post-operatively. Despite introduction of hardware, no patients had a recurrence of their infection in the 12 month follow up period. Single-stage debridement and instrumentation appeared to be a safe and effective method of managing spinal infections. The combination of debridement and fusion has the dual benefit of removing a focus of infection and stabilising the spine. The current series confirms that placing titanium cages into an infected space is safe in a majority of patients. Stabilisation and correction of spinal deformity reduces pain, aids neurologic recovery and improves quality of life. The small patient population and retrospective nature limit the present study.

Chromatin signaling in muscle stem cells: interpreting the regenerative microenvironment

Muscle regeneration in the adult occurs in response to damage at expenses of a population of adult stem cells, the satellite cells. Upon injury, either physical or genetic, signals released within the satellite cell niche lead to the commitment, expansion and differentiation of the pool of muscle progenitors to repair damaged muscle. To achieve this goal satellite cells undergo a dramatic transcriptional reprogramming to coordinately activate and repress specific subset of genes. Although the epigenetics of muscle regeneration has been extensively discussed, less emphasis has been put on how extra-cellular cues are translated into the specific chromatin reorganization necessary for progression through the myogenic program. In this review we will focus on how satellite cells sense the regenerative microenvironment in physiological and pathological circumstances, paying particular attention to the mechanism through which the external stimuli are transduced to the nucleus to modulate chromatin structure and gene expression. We will discuss the pathways involved and how alterations in this chromatin signaling may contribute to satellite cells dysfunction during aging and disease.

Delivery systems for the treatment of degenerated intervertebral discs

The intervertebral disc (IVD) is the most avascular and acellular tissue in the body and therefore prone to degeneration. During IVD degeneration, the balance between anabolic and catabolic processes in the disc is deregulated, amongst others leading to alteration of extracellular matrix production, abnormal enzyme activities and production of pro-inflammatory substances like cytokines. The established treatment strategy for IVD degeneration consists of physiotherapy, pain medication by drug therapy and if necessary surgery. This approach, however, has shown limited success. Alternative strategies to increase and prolong the effects of bioactive agents and to reverse the process of IVD degeneration include the use of delivery systems for drugs, proteins, cells and genes. In view of the specific anatomy and physiology of the IVD and depending on the strategy of the therapy, different delivery systems have been developed which are reviewed in this article.

Advancing the cellular and molecular therapy for intervertebral disc disease

The healthy intervertebral disc (IVD) fulfils the essential function of load absorption, while maintaining multi-axial flexibility of the spine. The interrelated tissues of the IVD, the annulus fibrosus, the nucleus pulposus, and the cartilaginous endplate, are characterised by their specific niche, implying avascularity, hypoxia, acidic environment, low nutrition, and low cellularity. Anabolic and catabolic factors balance a slow physiological turnover of extracellular matrix synthesis and breakdown. Deviations in mechanical load, nutrient supply, cellular activity, matrix composition and metabolism may initiate a cascade ultimately leading to tissue dehydration, fibrosis, nerve and vessel ingrowth, disc height loss and disc herniation. Spinal instability, inflammation and neural sensitisation are sources of back pain, a worldwide leading burden that is challenging to cure. In this review, advances in cell and molecular therapy, including mobilisation and activation of endogenous progenitor cells, progenitor cell homing, and targeted delivery of cells, genes, or bioactive factors are discussed.

Association between Interleukin-6 (G174C and G572C) promoter gene polymorphisms and risk of ischaemic stroke: A meta-analysis

BACKGROUND

Interleukin-6 (IL-6), as one of the most typical pro-inflammatory and immunoregulatory cytokines, is believed to be associated with the genesis and maintenance of inflammatory response. Genetic association studies (GAS) that have investigated the association between Interleukin 6 (G174C and G572C) promoter gene polymorphisms and susceptibility to ischemic stroke (IS) which have produced contradictory and unconvincing results.

PURPOSE

The aim of this meta-analysis is to provide a relatively comprehensive account of the association of IL-6 (G174C and G572C) polymorphisms with susceptibility to IS.

METHODS

A literature search was conducted using electronic database PubMed, Medline, and Trip database for all case-control studies investigating for association of IL-6 genetic polymorphisms with ischemic stroke published till August 30, 2014. The following combinations of main keywords were used: ('Interleukin-6' or 'IL-6') and ('ischaemic stroke or 'cerebral infarction' or 'IS') and ('genetic polymorphism' or 'single nucleotide polymorphisms' or 'SNP'). Pooled Odds ratios (ORs) and 95% confidence intervals (CIs) were determined for IL-6 gene-disease association. Meta-analysis was carried out using Revman 5.3 software.

RESULTS

16 case-control studies involving a total of 3,317 IS patients and 3,432 healthy controls for G174C polymorphism and 3 case-control studies with a total of 2,001 IS patients and 2,027 healthy controls for G572C IL-6 gene polymorphisms were included in a meta-analysis. For IL-6 G174C gene polymorphisms, no significant association was observed under dominant [GC + CC vs. GG: OR = 1.01, 95% CI: 0.77-1.34, P = 0. 92], recessive [CC vs. GG + GC: OR = 0.82, 95% CI: 0.40-1.70, P = 0. 59] and allelic model [C vs. G Allele: OR = 0.99, 95% CI: 0.74-1.31, P = 0. 93]. For IL-6 G572C, no significant association was observed under dominant [CC vs. GG + GC: OR = 0.99, 95% CI: 0.57-1.71, P = 0. 97], recessive [CC vs. GG + GC: OR = 0.93, 95% CI: 0.60-1.45, P = 0. 75] and allelic model [C vs. G Allele: OR = 0.95, 95% CI: 0.66-1.36, P = 0. 76].

CONCLUSION

This meta-analysis shows that IL-6 (G174C) and IL-6 (G572C) gene polymorphisms may not be associated with an increased susceptibility to IS. Further studies are required for confirmatory results.

Excessive growth hormone expression in male GH transgenic mice adversely alters bone architecture and mechanical strength

Patients with acromegaly have a higher prevalence of vertebral fractures despite normal bone mineral density (BMD), suggesting that GH overexpression has adverse effects on skeletal architecture and strength. We used giant bovine GH (bGH) transgenic mice to analyze the effects of high serum GH levels on BMD, architecture, and mechanical strength. Five-month-old hemizygous male bGH mice were compared with age- and sex-matched nontransgenic littermates controls (NT; n=16/group). Bone architecture and BMD were analyzed in tibia and lumbar vertebrae using microcomputed tomography. Femora were tested to failure using three-point bending and bone cellular activity determined by bone histomorphometry. bGH transgenic mice displayed significant increases in body weight and bone lengths. bGH tibia showed decreases in trabecular bone volume fraction, thickness, and number compared with NT ones, whereas trabecular pattern factor and structure model index were significantly increased, indicating deterioration in bone structure. Although cortical tissue perimeter was increased in transgenic mice, cortical thickness was reduced. bGH mice showed similar trabecular BMD but reduced trabecular thickness in lumbar vertebra relative to controls. Cortical BMD and thickness were significantly reduced in bGH lumbar vertebra. Mechanical testing of femora confirmed that bGH femora have decreased intrinsic mechanical properties compared with NT ones. Bone turnover is increased in favor of bone resorption in bGH tibia and vertebra compared with controls, and serum PTH levels is also enhanced in bGH mice. These data collectively suggest that high serum GH levels negatively affect bone architecture and quality at multiple skeletal sites.

Gene therapy approaches to regenerating the musculoskeletal system

Injuries to the musculoskeletal system are common, debilitating and expensive. In many cases, healing is imperfect, which leads to chronic impairment. Gene transfer might improve repair and regeneration at sites of injury by enabling the local, sustained and potentially regulated expression of therapeutic gene products; such products include morphogens, growth factors and anti-inflammatory agents. Proteins produced endogenously as a result of gene transfer are nascent molecules that have undergone post-translational modification. In addition, gene transfer offers particular advantages for the delivery of products with an intracellular site of action, such as transcription factors and noncoding RNAs, and proteins that need to be inserted into a cell compartment, such as a membrane. Transgenes can be delivered by viral or nonviral vectors via in vivo or ex vivo protocols using progenitor or differentiated cells. The first gene transfer clinical trials for osteoarthritis and cartilage repair have already been completed. Various bone-healing protocols are at an advanced stage of development, including studies with large animals that could lead to human trials. Other applications in the repair and regeneration of skeletal muscle, intervertebral disc, meniscus, ligament and tendon are in preclinical development. In addition to scientific, medical and safety considerations, clinical translation is constrained by social, financial and logistical issues.

Clinicopathologic features of IgA-dominant infection-associated glomerulonephritis: a pooled analysis of 78 cases

BACKGROUNDS

IgA-dominant infection-associated glomerulonephritis (IgA-dominant IAGN) is a unique form of glomerulonephritis. There are numerous case reports in the literature. However, the risk factors, treatment approach, and outcomes of the disease are not clearly characterized.

METHODS

We completed a pooled analysis based on published literature. Clinical features, laboratory findings, and histopathological changes were analyzed. A logistic regression model was employed to identify the determinants of disease outcome, for example, end-stage renal disease (ESRD) or death.

RESULTS

Seventy-eight patients with IgA-dominant IAGN from 28 reports were analyzed. All of these patients showed granular IgA deposits predominantly along the glomerular peripheral capillary walls using immunofluorescence and majority showed subepithelial 'hump-shaped' electron-dense deposits using electron microscopy. The majority of patients had hematuria (76/78), proteinuria (75/78), acute kidney injury (AKI) (66/78) and hypocomplementemia (43/75) without a previous history of renal disease. All of the patients had clinical infections at the time of presentation. Skin infections (19/78) and visceral abscesses (15/78) were frequently encountered, and staphylococcus was the most common pathogen. After treatment with antibiotics and/or supportive therapy, the renal function of 42 patients (54.5%) improved, 9 patients (11.7%) had persistent renal dysfunction, 15 patients (19.5%) progressed to ESRD, and 11 patients (14.3%) died. A multivariate regression analysis revealed that age (odds ratio [OR], 30.71; 95% confidence interval [CI], 2.53-373.07; p = 0.007) and diabetes mellitus (DM) (OR, 16.65; 95% CI, 1.18-235.84; p = 0.038) were independent risk factors for ESRD or death.

CONCLUSIONS

IgA-dominant IAGN has unique clinicopathological manifestations and treatment responses. Age and DM are independent risk factors associated with an unfavorable prognosis for IgA-dominant IAGN.

Bone marrow mesenchymal stem cells slow intervertebral disc degeneration through the NF-κB pathway

BACKGROUND CONTEXT

Previous studies have demonstrated the use of bone marrow mesenchymal stem cells (BMSCs) in tissue-engineering treatments to slow or reverse diseased intervertebral discs. Several approaches have successfully used the coculturing of stem cells with disc-native nucleus pulposus cells (NPCs) with the evidence of transformed BMSCs into NP-like cells, increased activity and matrix production by NPCs, or elements of both. The influence of the cytokine transforming growth factor-beta (TGF-β) in the differentiation of BMSCs into NP-like cells and its upregulation in coculture to increase matrix production are well established. However, the role of the inflammatory signaling molecule nuclear factor kappa B (NF-κB) in intervertebral disc degeneration is far less clear, although there is some existing evidence suggesting its role in the pathogenesis and progression of disc disease. A limited number of studies in other pathologies have alluded to the antagonistic relationship between both proteins. To date, there is no such investigation of their dynamic role in coculture of BMSCs and NPCs.

PURPOSE

The purpose of this study was to investigate the relationship of the regenerative effects of BMSCs cocultured with NPCs. The authors hypothesized that as levels of TGF-β increase in the coculture, the levels of NF-κB will concomitantly decrease. This would in turn be reflected by an increase in the expression of messenger RNA markers of the nucleus pulposus matrix that includes aggrecan, Type II collagen (CII), and SOX-9 and an increase in the cellular proliferation.

STUDY DESIGN/SETTING

This study is based on a coculture with the contact of rabbit NPCs and BMSCs.

METHODS

Bone marrow mesenchymal stem cells were cocultured with NPCs at a ratio of 1:1 and compared with BMSC and NPC controls cultured alone. Cell proliferation was evaluated by Cell Counting Kit-8 from 3 to 9 days. Gene expressions of aggrecan, CII, and SOX-9 was assayed by reverse transcription-polymerase chain reaction from 5 to 14 days. Detection of TGF-βl and NF-κB was determined by enzyme-linked immunosorbent assay, and immunohistochemical staining was carried out to evaluate CII synthesis.

RESULTS

After 3 days, cellular proliferation of the cocultured group exceeded that of controls. After 11 days, the expression of SOX-9 in the cocultured group had also exceeded controls. Furthermore, after 14 days, expressions of aggrecan and CII significantly exceeded controls. Immunohistochemical stains of CII in the NPC control group were positive at each point in time and demonstrated strongest expression at 14 days. Coculturing BMSCs with NPCs, therefore, seems to have resulted in the promotion of aggrecan, CII, and SOX-9 gene expressions. Finally, after 11 days, TGF-βl content of the cocultured group significantly exceeded control levels, whereas NF-κB content had significantly lowered.

CONCLUSIONS

Coculture of BMSCs may be able to delay NPC matrix degeneration potentially through the concomitant upregulation of TGF-β and the downregulation of NF-κB pathway.

Effects of nuclear factor kappa B signaling pathway in human intervertebral disc degeneration

STUDY DESIGN

IL-1β (interleukin-1β) can activate human nucleus pulposus cells with or without nuclear factor kappa B (NF-κB) inhibition. We undertook a descriptive and mechanistic investigation of catabolic effects of NF-κB signaling pathway in intervertebral disc degenerative changes.

OBJECTIVE

To clarify the mediatory role of NF-κB signaling pathway in human intervertebral disc degeneration (IDD).

SUMMARY OF BACKGROUND DATA

IDD is a major cause of lower back pain, 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 activation of NF-κB in many degenerative diseases, but its role in IDD has not been adequately explored.

METHODS

Human nucleus pulposus cells in monolayer culture were exposed to IL-1β, which increases matrix-degrading enzyme activity in the nucleus pulposus, with or without NF-κB inhibition by BAY11-7082; ribonucleic acid was isolated for real-time polymerase chain reaction analysis of gene expression, Western blot analysis was performed to detect the changes of protein expression.

RESULTS

NF-κB specific inhibitor BAY11-7082 significantly inhibited IL-1β-induced NF-κB activation. IL-1β-dependent gene upregulation of matrix metalloproteinase (MMP)-3, MMP-9, MMP-13, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-4, and ADAMTS-5 was significantly reduced by NF-κB inhibition. The decreased gene expression of aggrecan and type II collagen, induced by IL-1β was also reversed by BAY11-7082. NF-κB inhibition reversed the IL-1β-induced changes of protein expression of MMP-3, MMP-9, MMP-13, ADAMTS-4, ADAMTS-5, aggrecan, and type II collagen.

CONCLUSION

These findings demonstrate that the NF-κB signaling pathway is a key mediator of IDD and represents a therapeutic target for mitigating disc degenerative diseases.

LEVEL OF EVIDENCE

N/A.

Sonic Hedgehog signaling regulates vascular differentiation and function in human CD34 positive cells: vasculogenic CD34(+) cells with Sonic Hedgehog

Identification of pivotal factors potentially present in the in situ environment and capable of influencing the function of CD34(+) cells, which can be used for autologous cell therapy, is of paramount interest. SHh is one of the morphogens essential for embryonic vascular development as well as postnatal neovascularization, and the activation of SHh signaling with angiogenic and vascular differentiation responses in CD34(+) cells by SHh treatment differed depending on the G-CSF treatment or the background disease. SHh enhanced the migration, proliferation, adhesion, and EPC colony forming capacities of G-CSF mobilized CD34(+) cells, increasing the vasculogenic/angiogenic potential for neovascularization. An increase in the differentiation potential of CD34(+) cells toward vascular lineages was demonstrated with SHh treatment involving TGFβ signaling pathway. The SHh-activated G-CSF mobilized CD34(+) cells directly contributed to vascular regeneration while non-activated CD34(+) cells showed a lower regenerative capacity in a mouse ischemic hindlimb model. SHh signaling regulates human CD34(+) cell fate and function, and may potentiate the therapeutic effect of G-CSF mobilized CD34(+) cells on ischemic diseases.

Angiopoietin-1 enhances skeletal muscle regeneration in mice

Activation of muscle progenitor cell myogenesis and endothelial cell angiogenesis is critical for the recovery of skeletal muscle from injury. Angiopoietin-1 (Ang-1), a ligand of Tie-2 receptors, enhances angiogenesis and skeletal muscle satellite cell survival; however, its role in skeletal muscle regeneration after injury is unknown. We assessed the effects of Ang-1 on fiber regeneration, myogenesis, and angiogenesis in injured skeletal muscle (tibialis anterior, TA) in mice. We also assessed endogenous Ang-1 levels and localization in intact and injured TA muscles. TA fiber injury was triggered by cardiotoxin injection. Endogenous Ang-1 mRNA levels immediately decreased in response to cardiotoxin then increased during the 2 wk. Ang-1 protein was expressed in satellite cells, both in noninjured and recovering TA muscles. Positive Ang-1 staining was present in blood vessels but not in nerve fibers. Four days after the initiation of injury, injection of adenoviral Ang-1 into injured muscles resulted in significant increases in in situ TA muscle contractility, muscle fiber regeneration, and capillary density. In cultured human skeletal myoblasts, recombinant Ang-1 protein increased survival, proliferation, migration, and differentiation into myotubes. The latter effect was associated with significant upregulation of the expression of the myogenic regulatory factors MyoD and Myogenin and certain genes involved in cell cycle regulation. We conclude that Ang-1 strongly enhances skeletal muscle regeneration in response to fiber injury and that this effect is mediated through induction of the myogenesis program in muscle progenitor cells and the angiogenesis program in endothelial cells.

Clinical tests to diagnose lumbar spondylolysis and spondylolisthesis: A systematic review

The aim of this paper was to systematically review the diagnostic ability of clinical tests to detect lumbar spondylolysis and spondylolisthesis. A systematic literature search of six databases, with no language restrictions, from 1950 to 2014 was concluded on February 1, 2014. Clinical tests were required to be compared against imaging reference standards and report, or allow computation, of common diagnostic values. The systematic search yielded a total of 5164 articles with 57 retained for full-text examination, from which 4 met the full inclusion criteria for the review. Study heterogeneity precluded a meta-analysis of included studies. Fifteen different clinical tests were evaluated for their ability to diagnose lumbar spondylolisthesis and one test for its ability to diagnose lumbar spondylolysis. The one-legged hyperextension test demonstrated low to moderate sensitivity (50%-73%) and low specificity (17%-32%) to diagnose lumbar spondylolysis, while the lumbar spinous process palpation test was the optimal diagnostic test for lumbar spondylolisthesis; returning high specificity (87%-100%) and moderate to high sensitivity (60-88) values. Lumbar spondylolysis and spondylolisthesis are identifiable causes of LBP in athletes. There appears to be utility to lumbar spinous process palpation for the diagnosis of lumbar spondylolisthesis, however the one-legged hyperextension test has virtually no value in diagnosing patients with spondylolysis.

Impact of Intercellular Adhesion Molecule-1 Genetic Polymorphisms on Coronary Artery Disease Susceptibility in Taiwanese Subjects

The principal pathogenesis of coronary artery disease (CAD) is coronary artery atherosclerosis, a chronic inflammatory disease of the vessel walls of the coronary artery. Intercellular adhesion molecule-1 (ICAM-1) displays an important role in the development of the inflammation reaction and atherosclerosis. Few studies report the association of ICAM-1 genetic polymorphisms with CAD in Taiwanese subjects. Therefore, we conducted a study to associate the single nucleotide polymorphisms (SNPs) of ICAM-1, rs5491, rs5498, rs281432 and rs3093030 with CAD. Five hundred and twenty-five male and female subjects, who received elective coronary angiography in Taiwan Chung Shan Medical University Hospital, were recruited to determine four ICAM-1 SNPs by real time-polymerase chain reaction and genotyping. The relationships among ICAM-1 SNPs, haplotypes, demographic and characteristics and CAD were analyzed. This study showed that rs281432 (C8823G) was the only ICAM-1 SNP which affect the development of CAD. Multivariate analysis revealed that ICAM-1 SNP rs281432 CC/CG [p=0.016; odds ratio (OR): 2.56, 95% confidence interval (CI): 1.19-5.56], male gender (p=0.018; OR: 1.66, 95% CI: 1.09-2.51), aspirin use in the past 7 days (p=0.001; OR: 2.05, 95% CI: 1.33-3.14), hypertension (p<0.001; OR: 2.15, 95% CI: 1.42-3.25), serum cardiac troponin I elevation (p<0.001; OR: 2.14, 95% CI: 1.47-3.24) and severe angina in recent 24 hours (p=0.001; OR: 1.97, 95% CI: 1.31- 2.95) increase the risk of CAD. In conclusion, ICAM-1 SNP rs281432 is an independent factor to predict the development of CAD. ICAM-1 SNP rs281432 homozygotic mutant GG can reduce the susceptibility to the CAD in Taiwanese subjects.

Occupational and genetic risk factors for osteoarthritis: a review

BACKGROUND

Osteoarthritis (OA) is a multifactorial disease with strong genetic and occupational components. Although published studies have described several risk factors for OA, very few studies have investigated the occupational and genetic factors that contribute to this debilitating condition.

OBJECTIVE

To describe occupational and genetic factors that may contribute to the risk of developing (OA).

METHODS

A literature search was conducted in PubMed using the search terms osteoarthritis, occupation, work, and genetics.

RESULTS

Heavy physical work load was the most common occupational risk factor for OA in several anatomical locations. Other factors include kneeling and regular stair climbing, crawling, bending and whole body vibration, and repetitive movements. Numerous studies have also shown the influence of genetic variability in the pathogenesis of OA. Genetic variants of several groups of genes e.g., cartilage extracellular matrix structural genes and the genes related to bone density have been implicated in disease pathogenesis.

CONCLUSION

This review shows that occupational factors were extensively studied in knee OA unlike OA of other anatomical regions. Although genetic association studies performed to date identified a number of risk variants, some of these associations have not been consistently replicated across different studies and populations. Therefore, more research is needed.

Biocompatibility of a coacervate-based controlled release system for protein delivery to the injured spinal cord

The efficacy of protein-based therapies for treating injured nervous tissue is limited by the short half-life of free proteins in the body. Affinity-based biomaterial delivery systems provide sustained release of proteins, thereby extending the efficacy of such therapies. Here, we investigated the biocompatibility of a novel coacervate delivery system based on poly(ethylene argininylaspartate diglyceride) (PEAD) and heparin in the damaged spinal cord. We found that the presence of the [PEAD:heparin] coacervate did not affect the macrophage response, glial scarring or nervous tissue loss, which are hallmarks of spinal cord injury. Moreover, the density of axons, including serotonergic axons, at the injury site and the recovery of motor and sensorimotor function were comparable in rats with and without the coacervate. These results revealed the biocompatibility of our delivery system and supported its potential to deliver therapeutic proteins to the injured nervous system.

Biomimetic scaffolds facilitate healing of critical-sized segmental mandibular defects

OBJECTIVE

To investigate the efficacy of biomimetic PLGA scaffolds, alone and in combination with bone morphogenic protein (BMP-2) and adipose-derived stem cells (ASCs), to heal a critical-sized segmental mandibular defect in a rat model.

STUDY DESIGN

Prospective animal study.

METHODS

ASCs were isolated and cultured from the inguinal fat of Lewis rat pups. Using three-dimensional printing, PLGA scaffolds were fabricated and impregnated with BMP-2 and/or ASCs. Critical-sized 5-mm segmental mandibular defects were created in adult Lewis rats and implanted with (1) blank PLGA scaffolds, (2) PLGA scaffolds with ASCs, (3) PLGA scaffolds with BMP, or (4) PLGA scaffolds with BMP and ASCs. Animals were sacrificed at 12weeks. Bone regeneration was assessed using microCT, and graded on a semi-quantitative bone formation and bone union scale.

RESULTS

Twenty-eight rats underwent creation of segmental mandibular defects with implantation of scaffolds. Nine rats suffered complications and were excluded from analysis, leaving 19 animals for inclusion in the study. MicroCT analysis demonstrated no bridging of the segmental bony defect in rats implanted with blank scaffolds (median bone union score=0). Rats implanted with scaffolds containing BMP-2 (median bone union=2.0), ASCs (median bone union=1.5), and combination of BMP and ASCs (median bone union=1.0) demonstrated healing of critical-sized segmental mandibular defects. Bone regeneration was most robust in the BMP-2 treated scaffolds.

CONCLUSIONS

The current study utilizes a novel animal model to study the efficacy of biomimetic scaffolds carrying osteogenic factors to induce healing of a critical-sized segmental mandibular defect.

LEVEL OF EVIDENCE

N/A, Basic Science Animal Research.

Optimization of segmental lumbar spine instability treatment using minimally invasive spinal fusion technique

Open transforaminal lumbar interbody fusion (TLIF) using transpedicular rods and interbody cage, which is used to treat segmental instability, is associated with a significant paravertebral muscle and ligament injury. A new rigid fusion method was introduced to improve the outcome of patients' treatment.

OBJECTIVE

To conduct a comparative analysis of the effectiveness of minimally invasive fusion technique and TLIF to improve the treatment results in patients with symptomatic lumbar spine degeneration concomitant with moderate segmental instability of the lumbar spine.

MATERIAL AND METHODS

The study involved 90 patients, which were divided into 2 groups. Transforaminal interbody fusion with Pezo-T PEEK cage was performed after spinal canal reconstruction in both groups. In the first group (n=45), interbody fusion was augmented by 4-point transpedicular rod fixation (Konmet, Russia); in the second group (n=45), by Coflex-F rigid interspinous spacer. Patients were followed up and the results were assessed within 24 months after surgery.

RESULTS

The intergroup comparison of pain level using the visual analogue scale, the need for analgesics, and quality of life according to Oswestry Disability Index score during the early postoperative period demonstrated significantly better outcomes in the second group of patients due to lesser operative trauma of the paravertebral soft tissue. Interbody fusion was observed within 20-36 months in 95% of group I patients and 94% of group II patients (p>0.05). Postoperative complications were observed in 17.8% of patients in group I and in 2.2% of cases in group II (p<0.001).

CONCLUSION

Stabilization by rigid interspinous spacer and transforaminal interbody cage provides better clinical outcomes and fewer postoperative complications as compared to the conventional TLIF technique with similar X-ray rate of bone block formation in patients with moderate segmental instability of the lumbar spine, thus optimizing the treatment of such patients.

Surgical treatment for idiopathic intervertebral disc calcification in a child: case report and review of the literature

PURPOSE

Intervertebral disc calcification (IDC) is rare in children. Conservative treatment has been recommended for the majority of cases. We describe surgical treatment of a case of IDC with progressive neurological impairment and review the literature relevant to this rare entity and its management.

METHODS

A 16-year-old boy presented with sudden onset of severe neck pain, radiating into his left shoulder. Three months later, he developed neurological symptoms and signs with a progressive motor and sensory loss of his left upper limb.

RESULTS

Anterior cervical corpectomy with fusion and instrumentation was performed. Neurologic deficits completely resolved within 1 week. After 1-year follow-up, radiological images showed solid fusion and no further compression.

CONCLUSION

Surgical decompression should be recommended for cases with acutely progressive and severe neurological impairments in IDC and a good result can be obtained. When surgery is needed, anterior decompression is usually used in cervical lesion, while in thoracic and lumbar area, posterior approach is suggested.

Comparison of two-stage open versus percutaneous pedicle screw fixation in treating pyogenic spondylodiscitis

Background

Percutaneous pedicle screw instrumentation is a minimally invasive surgical technique; however, the effects of using percutaneous pedicle screw fixation in treating patients with spinal infections have not yet been well demonstrated. The aim of this study, therefore, was to determine whether percutaneous posterior pedicle screw instrumentation is superior to the traditional open approach in treating pyogenic spondylodiscitis.

Methods

We retrospectively reviewed data for 45 patients treated for pyogenic spondylodiscitis with anterior debridement and interbody fusion followed by a second-stage procedure involving either traditional open posterior pedicle screw fixation or percutaneous posterior pedicle screw fixation. Twenty patients underwent percutaneous fixation and 25 patients underwent open fixation. Demographic, operative, and perioperative data were collected and analyzed.

Results

The average operative time for the percutaneous procedure was 102.5 minutes, while the average time for the open procedure was 129 minutes. The average blood loss for the percutaneous patients was 89 ml versus a 344.8 ml average for the patients in the open group. Patients who underwent the minimally invasive surgery had lower visual analogue scale scores and required significantly less analgesia afterwards. After two years of follow-up, neither recurrent infection nor intraoperative complications, such as wound infection or screw loosening, were found in the percutaneous group. Moreover, there was no significant difference in outcome between the two groups in terms of Oswestry Disability Index scores.

Conclusions

Anterior debridement and interbody fusion with bone grafting followed by minimally invasive percutaneous posterior instrumentation is an alternative treatment for pyogenic spondylodiscitis which can result in less intraoperative blood loss, shorter operative time, and reduced postoperative pain with no adverse effect on infection control.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2474-15-443) contains supplementary material, which is available to authorized users.

Intercellular adhesion molecule-1 K469E polymorphism and risk of coronary artery disease: a meta-analysis

Background

Intercellular adhesion molecule-1 (ICAM-1) K469E polymorphism has been implicated in susceptibility to coronary artery disease (CAD). Several studies investigated the association of this polymorphism with CAD in different populations but the results were contradictory. A meta-analysis was conducted to assess the association between ICAM-1 K469E polymorphism and CAD susceptibility.

Material/Methods

Databases including PubMed, EMBASE, China National Knowledge Infrastructure (CNKI), and Weipu Database were searched to find relevant studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations. A random-effects model was used.

Results

Fifteen case-control studies including 3088 cases and 3466 controls were included. Overall, a significant association between ICAM-1 K469E polymorphism and CAD was observed in the dominant model (OR=1.80; 95% CI 1.62–2.01; P<0.00001; P_{heterogeneity}=0.40). In subgroup analysis by ethnicity, a significant association was found among Asians (OR=1.92; 95% CI 1.51–2.43; P<0.00001; P_{heterogeneity}=0.98) and among Caucasians (OR=1.64; 95% CI 1.30–2.08; P<0.0001; P_{heterogeneity}=0.04). In the subgroup analysis by age, a significant association was found among young patients (OR=1.46; 95% CI 1.10–1.93; P=0.008; P_{heterogeneity}=0.21) and old patients (OR=1.92; 95% CI 1.75–2.10; P<0.00001; P_{heterogeneity}=0.99).

Conclusions

Results of this meta-analysis suggest that ICAM-1 K469E polymorphism confers a risk factor of CAD.

Salidroside exerts angiogenic and cytoprotective effects on human bone marrow-derived endothelial progenitor cells via Akt/mTOR/p70S6K and MAPK signalling pathways

BACKGROUND AND PURPOSE

With the increase of age, increased susceptibility to apoptosis and senescence may contribute to proliferative and functional impairment of endothelial progenitor cells (EPCs). The aim of this study was to investigate whether salidroside (SAL) can induce angiogenic differentiation and inhibit oxidative stress-induced apoptosis in bone marrow-derived EPCs (BM-EPCs), and if so, through what mechanism.

EXPERIMENTAL APPROACH

BM-EPCs were isolated and treated with different concentrations of SAL for up to 4 days. Cell proliferation, migration and tube formation ability were detected by DNA content quantification, transwell assay and Matrigel-based angiogenesis assay. Gene and protein expression were assessed by qRT-PCR and Western blot respectively.

KEY RESULTS

Treatment with SAL promoted cellular proliferation and angiogenic differentiation of BM-EPCs, and increased VEGF and NO secretion, which in turn mediated the enhanced angiogenic differentiation of BM-EPCs. Furthermore, SAL significantly attenuated hydrogen peroxide (H₂O₂)-induced cell apoptosis, reduced the intracellular level of reactive oxygen species and restored the mitochondrial membrane potential of BM-EPCs. Moreover, SAL stimulated the phosphorylation of Akt, mammalian target of rapamycin and p70 S6 kinase, as well as ERK1/2, which is associated with cell migration and capillary tube formation. Additionally, SAL reversed the phosphorylation of JNK and p38 MAPK induced by H₂O₂ and suppressed the changes in the Bax/Bcl-xL ratio observed after stimulation with H₂O₂.

CONCLUSIONS AND IMPLICATIONS

These findings identify novel mechanisms that regulate EPC function and suggest that SAL has therapeutic potential as a new agent to enhance vasculogenesis as well as protect against oxidative endothelial injury.

Association of GPR126 gene polymorphism with adolescent idiopathic scoliosis in Chinese populations

Idiopathic scoliosis is the most common pediatric spinal deformity affecting 1% to 3% of the population, and adolescent idiopathic scoliosis (AIS) accounts for approximately 80% of these cases; however, the etiology and pathogenesis of AIS are still uncertain. The current study aims to identify the relationship between G protein-coupled receptor 126 (GPR126) gene and AIS predisposition, to identify the relationship between the genotypes of the GPR126 SNPs and the clinical phenotypes of AIS. We conducted a case-control study and genotyped twenty SNPs of GPR126 gene including ten exonic SNPs and ten intronic polymorphisms in 352 Chinese sporadic AIS patients and 149 healthy controls. We provided evidence for strong association of three intronic SNPs of the GPR126 gene with AIS susceptibility: rs6570507 A > G (p =0 .0035, OR = 1.729), rs7774095 A > C (p = 0.0078, OR = 1.687), and rs7755109 A > G (p = 0.0078, OR = 1.687). However, we did not identify any significant association between ten exonic SNPs of GPR126 and AIS. Linkage disequilibrium analysis indicated that rs7774095 A > C and rs7755109 A > G could be parsed into one block. The association between the intronic haplotype and AIS was further confirmed in an independent population with 110 AIS individuals and 130 healthy controls (p = 0.046, OR = 1.680). Furthermore, molecular mechanisms underlying intronic SNP regulation of GPR126 gene were studied. Although intronic SNPs associated with AIS didn't influence GPR126 mRNA alternative splicing, there was a strong association of rs7755109 A > G with decreased GPR126 mRNA level and protein levels. Our findings indicate that genetic variants of GPR126 gene are associated with AIS susceptibility in Chinese populations. The genetic association of GPR126 gene and AIS might provide valuable insights into the pathogenesis of adolescent idiopathic scoliosis.

Acromegaly and bone disease

PURPOSE OF REVIEW

To provide an update on current understanding of osteoporosis associated with acromegaly.

RECENT FINDINGS

Patients with acromegaly have an increased risk of morphometric vertebral fractures. This seems to correlate with acromegaly activity and its duration, but it persists after biochemical control is achieved. Coexistent hypogonadism, diabetes mellitus and over-replacement with glucocorticoids have additional detrimental effects. Bone mineral density can be normal, increased or decreased, and is usually discordant with occurrence of fractures. However, a decrease in the hip bone mineral density during follow-up has been associated with development of new vertebral fractures. Bone turnover markers are increased and tend to normalize after biochemical control of acromegaly. Hypercalcemia rarely occurs in acromegaly and may be parathyroid hormone-dependent or 1,25 dihydroxy-vitamin D dependent. The latter improves with biochemical control of acromegaly.

SUMMARY

Screening with thoracic and lumbar vertebral radiographs is indicated in patients with acromegaly. We recommend biochemical control of acromegaly, treatment of hypogonadism and other risk factors of osteoporosis and avoiding supraphysiologic doses of glucocorticoids. Further studies are needed to understand mechanisms of skeletal fragility in acromegaly and clinical impact of vertebral fractures. Further studies of tailored therapy for patients with acromegaly and osteoporosis are also needed.

Mitochondria-targeted ROS scavenger improves post-ischemic recovery of cardiac function and attenuates mitochondrial abnormalities in aged rats

Mitochondria-generated reactive oxygen species (ROS) play a crucial role in the pathogenesis of aging and age-associated diseases. In this study, we evaluated the effects of XJB-5-131 (XJB), a mitochondria-targeted ROS and electron scavenger, on cardiac resistance to ischemia-reperfusion (IR)-induced oxidative stress in aged rats. Male adult (5-month old, n=17) and aged (29-month old, n=19) Fischer Brown Norway (F344/BN) rats were randomly assigned to the following groups: adult (A), adult+XJB (AX), aged (O), and aged+XJB (OX). XJB was administered 3 times per week (3mg/kg body weight, IP) for four weeks. At the end of the treatment period, cardiac function was continuously monitored in excised hearts using the Langendorff technique for 30 min, followed by 20 min of global ischemia, and 60-min reperfusion. XJB improved post-ischemic recovery of aged hearts, as evidenced by greater left ventricular developed-pressures and rate-pressure products than the untreated, aged-matched group. The state 3 respiration rates at complexes I, II and IV of mitochondria isolated from XJB-treated aged hearts were 57% (P<0.05), 25% (P<0.05) and 28% (P<0.05), respectively, higher than controls. Ca(2+)-induced swelling, an indicator of permeability transition pore opening, was reduced in the mitochondria of XJB-treated aged rats. In addition, XJB significantly attenuated the H2O2-induced depolarization of the mitochondrial inner membrane as well as the total and mitochondrial ROS levels in cultured cardiomyocytes. This study underlines the importance of mitochondrial ROS in aging-induced cardiac dysfunction and suggests that targeting mitochondrial ROS may be an effective therapeutic approach to protect the aged heart against IR injury.

Clinical experience with tranexamic acid during primary total hip arthroplasty

We examined whether a single 1-gram preoperative dose of tranexamic acid (TXA) was effective in reducing 1) allogeneic blood transfusion, 2) haemoglobin (Hb) decreases, and 3) perioperative blood loss following primary total hip arthroplasty (THA) and resurfacing hip arthroplasty (RHA). One hundred and thirty-two patients (88 THA, 44 RHA; 66M, 66F; mean age = 58.2 years) who received TXA were compared with a control group matched for starting Hb, body mass index (BMI), age and gender. For the THR, transfusion rates were 4.5% and 19.3% for the TXA and control groups, respectively (p = 0.001) with no difference for the resurfacing patients. The mean overall Hb decrease was significantly lower in the TXA treatment groups for both THA and RHA patients (p<0.0001 and p = 0.01 respectively). 1 g of tranexamic acid administered preoperatively significantly reduced the mean decrease in haemoglobin as well as risk of transfusion.

Roles for Hedgehog signaling in adult organ homeostasis and repair

The hedgehog (HH) pathway is well known for its mitogenic and morphogenic functions during development, and HH signaling continues in discrete populations of cells within many adult mammalian tissues. Growing evidence indicates that HH regulates diverse quiescent stem cell populations, but the exact roles that HH signaling plays in adult organ homeostasis and regeneration remain poorly understood. Here, we review recently identified functions of HH in modulating the behavior of tissue-specific adult stem and progenitor cells during homeostasis, regeneration and disease. We conclude that HH signaling is a key factor in the regulation of adult tissue homeostasis and repair, acting via multiple different routes to regulate distinct cellular outcomes, including maintenance of plasticity, in a context-dependent manner.

Pyrroloquinoline quinone protects nucleus pulposus cells from hydrogen peroxide-induced apoptosis by inhibiting the mitochondria-mediated pathway

PURPOSE

Intervertebral disc cell apoptosis has been suggested to play a key role in promoting disc degeneration, and many studies have shown that the mechanism may be related to oxidative stress. Pyrroloquinoline quinone (PQQ), a redox cofactor for bacterial dehydrogenases, possesses the potential to scavenge reactive oxygen species (ROS) and inhibit cell apoptosis. The objective of this study was to evaluate the effects of PQQ on cultured rat nucleus pulposus (NP) cells under conditions of oxidative injury induced by hydrogen peroxide (H2O2) and to investigate the underlying mechanisms in vitro.

METHODS

Cell viability was determined by CCK8 assay. Changes in the apoptosis rate, intracellular ROS levels and the mitochondrial membrane potential were measured by flow cytometry. Extracellular matrix (ECM)-related proteins (collagen-2 and aggrecan) and apoptosis-related proteins (Bcl-2, Bax, cytochrome c, and caspase-3) were investigated by western blotting.

RESULTS

The results show that NP cells pretreated with PQQ before H2O2 exposure exhibited increased cell viability, decreased ROS formation, maintained mitochondrial membrane potential, and reduced apoptosis. In the presence of PQQ, ECM production was maintained by the cells despite being in an apoptotic environment. In addition, pretreatment with PQQ increased the expression of Bcl-2, inhibited the release of mitochondrial cytochrome c, and decreased the expressions of Bax and cleaved caspase-3.

CONCLUSIONS

Our results suggest that PQQ can protect rat NP cells against oxidative stress via a mitochondria-mediated pathway. PQQ might be useful as a potential pharmaceutical agent in the prevention of intervertebral disc degeneration.

Grafting and early expression of growth factors from adipose-derived stem cells transplanted into the cochlea, in a Guinea pig model of acoustic trauma

Noise exposure causes damage of multiple cochlear cell types producing permanent hearing loss with important social consequences. In mammals, no regeneration of either damaged hair cells or auditory neurons has been observed and no successful treatment is available to achieve a functional recovery. Loads of evidence indicate adipose-derived stem cells (ASCs) as promising tools in diversified regenerative medicine applications, due to the high degree of plasticity and trophic features. This study was aimed at identifying the path of in vivo cell migration and expression of trophic growth factors, upon ASCs transplantation into the cochlea, following noise-induced injury. ASCs were isolated in primary culture from the adipose tissue of a guinea pig, transduced using a viral vector to express the green fluorescent protein, and implanted into the scala tympani of deafened animals. Auditory function was assessed 3 and 7 days after surgery. The expression of trophic growth factors was comparatively analyzed using real-time PCR in control and noise-injured cochlear tissues. Immunofluorescence was used to assess the in vivo localization and expression of trophic growth factors in ASCs and cochleae, 3 and 7 days following homologous implantation. ASC implantation did not modify auditory function. ASCs migrated from the perilymphatic to the endolymphatic compartment, during the analyzed time course. Upon noise exposure, the expression of chemokine ligands and receptors related to the PDGF, VEGF, and TGFbeta pathways, increased in the cochlear tissues, possibly guiding in vivo cell migration. Immunofluorescence confirmed the increased expression, which appeared to be further strengthened by ASCs’ implantation. These results indicated that ASCs are able to migrate at the site of tissue damage and express trophic factors, upon intracochlear implantation, providing an original proof of principle, which could pave the way for further developments of ASC-based treatments of deafness.

Gene expression-based enrichment of live cells from adipose tissue produces subpopulations with improved osteogenic potential

Introduction

Mesenchymal stem cells have been increasingly used for cell-based therapies. Adipose-derived stem/stromal cells (ASCs) from the stromal vascular fraction (SVF) of fat tissue are a particularly attractive option for cell based therapy given their accessibility and relative abundance. However, their application in both clinical and basic science investigations is complicated by the isolation of differentiable cells within the SVF. Current enrichment strategies, such as monolayer passaging and surface marker-based sorting, can be time-consuming or overly stringent. Ideally, a population of cells with great regenerative capacity could be isolated with high yields so that extensive in vitro manipulation is not necessary. The objective of this study was to determine whether SVF cells sorted based on expression of alkaline phosphatase liver/bone/kidney (ALPL) resulted in populations with increased osteogenic differentiation potential.

Methods

SVF samples were obtained from four, human donors and processed to isolate initial, heterogeneous cell populations. These SVF cells underwent a four day osteogenic priming period, after which they were treated with a fluorescent, oligodeoxynucleotide molecular beacon probe specific for ALPL mRNA. Cells were separated into positive and negative groups using fluorescence-activated cell sorting (FACS) then differentiated down the osteogenic lineage. Differentiation was assessed by measuring calcified matrix production in each sample.

Results

Cells positive for ALPL expression (ALPL+) represented approximately 34% of the gated population, while cells negative for ALPL expression (ALPL-) represented approximately 18%. ALPL+ cells produced 3.7-fold and 2.1-fold more calcified matrix than ALPL- and unsorted SVF cells, respectively, indicating a significant improvement in osteogenic differentiation. Further, ALPL+ cells showed increases in metabolite production for both adipogenesis and chondrogenesis, suggesting that the enrichment process yields an enhanced multipotent phenotype. Osteogenic differentiation response and cell yields for ALPL+ cells were markedly improved over surface marker-sorted samples.

Conclusion

This study demonstrates a novel method to enrich heterogeneous SVF cells for increased osteogenic potential. The procedure requires less time and results in higher yields of therapeutically useful cells than other existing approaches. Gene expression-based sorting of MSCs is a potentially paradigm-shifting approach that could benefit applications spanning from basic science to clinical therapy.

Electronic supplementary material

The online version of this article (doi:10.1186/scrt502) contains supplementary material, which is available to authorized users.

Impact of smoking on complication and pseudarthrosis rates after single- and 2-level posterolateral fusion of the lumbar spine

STUDY DESIGN

Retrospective study.

OBJECTIVE

To study the impact of smoking status on postoperative complications and pseudarthrosis in adult patients undergoing posterolateral fusion (PLF) of the lumbar spine.

SUMMARY OF BACKGROUND DATA

Results of studies analyzing the impact of smoking on complication and pseudarthrosis rates after spine surgery are conflicting.

METHODS

A retrospective medical record review was performed to identify all adult patients who underwent single- and 2-level instrumented PLF without interbody devices for degenerative spine disease in a 21-year period at a single institution. Patients were divided into smokers and nonsmokers. The main outcome variables were development of at least one postoperative complication and development of pseudarthrosis.

RESULTS

A total of 281 patients underwent single- or 2-level PLF in the 21-year period. Of these, 231 (82.21%) patients were nonsmokers and 50 (17.9%) were smokers. For patients undergoing single-level PLF, complication rates in nonsmokers (3.57%) versus smokers (7.69%) were not significantly different (P = 0.353); pseudarthrosis in nonsmokers occurred in 9.82% of cases compared with 7.69% in the smokers group (P = 0.738). Nonsmokers undergoing 2-level PLF had complication rates of 6.72%, compared with 4.17% in smokers (P = 0.638), but pseudarthrosis rates were significantly higher in the smokers group than in the nonsmokers group (29.17% vs. 10.92%; P = 0.019). Patients were followed up for an average of 53.5 months.

CONCLUSION

The findings in this study suggest that smoking has a significant impact on pseudarthrosis rates after 2-level PLF of the lumbar spine, but not necessarily on single-level PLF.

LEVEL OF EVIDENCE

4.

Bone substitutes in orthopaedic surgery: from basic science to clinical practice

Bone substitutes are being increasingly used in surgery as over two millions bone grafting procedures are performed worldwide per year. Autografts still represent the gold standard for bone substitution, though the morbidity and the inherent limited availability are the main limitations. Allografts, i.e. banked bone, are osteoconductive and weakly osteoinductive, though there are still concerns about the residual infective risks, costs and donor availability issues. As an alternative, xenograft substitutes are cheap, but their use provided contrasting results, so far. Ceramic-based synthetic bone substitutes are alternatively based on hydroxyapatite (HA) and tricalcium phosphates, and are widely used in the clinical practice. Indeed, despite being completely resorbable and weaker than cortical bone, they have exhaustively proved to be effective. Biomimetic HAs are the evolution of traditional HA and contains ions (carbonates, Si, Sr, Fl, Mg) that mimic natural HA (biomimetic HA). Injectable cements represent another evolution, enabling mininvasive techniques. Bone morphogenetic proteins (namely BMP2 and 7) are the only bone inducing growth factors approved for human use in spine surgery and for the treatment of tibial nonunion. Demineralized bone matrix and platelet rich plasma did not prove to be effective and their use as bone substitutes remains controversial. Experimental cell-based approaches are considered the best suitable emerging strategies in several regenerative medicine application, including bone regeneration. In some cases, cells have been used as bioactive vehicles delivering osteoinductive genes locally to achieve bone regeneration. In particular, mesenchymal stem cells have been widely exploited for this purpose, being multipotent cells capable of efficient osteogenic potential. Here we intend to review and update the alternative available techniques used for bone fusion, along with some hints on the advancements achieved through the experimental research in this field.

Meta-epidemiology

The concept of meta-epidemiology has been introduced with considering the methodological limitations of systematic review for intervention trials. The paradigm of meta-epidemiology has shifted from a statistical method into a new methodology to close gaps between evidence and practice. Main interest of meta-epidemiology is to control potential biases in previous quantitative systematic reviews and draw appropriate evidences for establishing evidence-base guidelines. Nowadays, the network meta-epidemiology was suggested in order to overcome some limitations of meta-epidemiology. To activate meta-epidemiologic studies, implementation of tools for risk of bias and reporting guidelines such as the Consolidated Standards for Reporting Trials (CONSORT) should be done.

Posterior percutaneous reduction and fixation of thoraco-lumbar burst fractures

BACKGROUND

Treatment of A3 thoraco-lumbar and lumbar spinal fractures nowadays remains a controversial issue. Percutaneous techniques are becoming very popular in the last few years to reduce the approach-related morbidity associated with conventional techniques.

HYPOTHESIS

Purpose of the study was to analyze the clinical and radiological outcome of patients who underwent percutaneous posterior fixation without fusion for the treatment of thoraco-lumbar and lumbar A3 fractures.

MATERIALS AND METHODS

Sixty-three patients, having sustained a single-level thoraco-lumbar fracture, underwent short segment percutaneous instrumentation and were retrospectively analyzed. sagittal index (SI) was calculated in all patients. Clinical and functional outcome were evaluated by Visual Analog Scale (VAS), Oswestry Disability Index (ODI) and Short Form General Health Status (SF-36).

RESULTS

Average operative blood loss was 82 mL (50-320). Mean pre-operative SI in the thoraco-lumbar segment was 13.3° decreased to 5.8° in the immediate postoperative with a mean deformity correction of 7.5. Mean pre-operative SI in the lumbar segment was 16.5° decreased to 11.3° in the immediate postoperative with a mean deformity correction of 5.2. Not statistically significant correction loss was registered at 1-year minimum follow-up. Constant clinical conditions improvement in the examined patients was observed.

CONCLUSION

Percutaneous pedicle screw fixation for A3 thoraco-lumbar and lumbar spinal fractures is a reliable and safe procedure.

LEVEL OF EVIDENCE

Level IV. Retrospective study.

Predictors and complications of blood transfusion in total hip and knee arthroplasty

Perioperative patient optimization can minimize the need for blood transfusions in patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA). The purpose of this study was to determine predictors and complications of transfusions. This retrospective review analyzed 1795 patients who underwent primary THA and TKA at our institution between January 2011 and December 2012. Of the 1573 patients ultimately included the rates of transfusion were 9.27% in TKA and 26.6% in THA. Significant predictors for transfusion include: preoperative hemoglobin, age, female gender, body mass index, creatinine, TKA, operating room time, operative blood loss, and intra-operative fluids. The DVT rate was comparable, but deep surgical site infection rate among transfused patients was 2.4% compared to 0.5% in non-transfused patients (P = 0.0065).

Knee flexion after total knee arthroplasty reduces blood loss

PURPOSE

Extensive blood loss after total knee arthroplasty (TKA) may be a potential problem since it leads to anaemia, increased need for transfusion and prolonged hospitalization. Aim of this study was to investigate the effects of postoperative knee flexion after TKA on blood loss and the need for transfusion.

METHODS

One hundred consecutive patients undergoing primary TKA from 2012 to 2013 were randomizely divided into two groups. In one group, the knee was extended for the first 6 h after surgery, whereas in the other was flexed at 90° for the same time. Two doses of endovenous tranexamic acid were administered in all subjects. Patients were homogeneous for all the possible confounding factors.

RESULTS

Calculated blood loss was 846 ± 197 (ml) in the flexion group and 1,242 ± 228 (ml) in the extension group (p < 0.05). Drop of haemoglobin levels at 24 h in the study group and the control group was 1.9 ± 0.8 (g/dl) and 3.0 ± 0.5 (g/dl), respectively (p < 0.01). Drop of haematocrit at 24 h was 4.5 ± 0.2 (%) in the flexion group and 6.7 ± 0.3 (%) in the extension group (p < 0.05). Blood transfusion was necessary in 5 patients in the control group and was not necessary in any patient of the study group. Average knee flexion at day 7 was 105° ± 4° in the flexion group and 98° ± 7° in the extension group.

CONCLUSION

Knee flexion at 90° after TKA, associated with the intraoperative use of tranexamic, acid is an effective method to reduce blood loss and the need for blood transfusion. The routine use of the present protocol is effective in reducing social costs and length of hospitalization of TKA procedures.