Non-steroidal anti-inflammatory drugs, cyclooxygenase-2 and the bone healing process

Spontaneous Reossification Following Craniectomy in a Pediatric Patient

Spontaneous reossification following a cranial defect is described by only a few case reports. A 6-month-old male with epidural hematoma underwent decompressive craniotomy, subsequently complicated by scalp abscess requiring removal of the bone flap. On serial outpatient follow-up, the patient demonstrated near-complete resolution of cranial defect over the course of 18 months, thus deferring the need for future cranioplasty. Prior articles have identified this occurrence in children and young adults; however, the present case is the first to report of this phenomenon in an infant less than 1 year of age. A brief review of the literature is provided with the proposed physiologic underpinning for the spontaneous reossification observed. While prior studies propose that recranialization is mediated by contact with the dura mater and pericranium, new investigations suggest that calvarial bone repair is also mediated by stem cells from the suture mesenchyme.

Biomechanics in the onset and severity of spondyloarthritis: a force to be reckoned with

Increasing evidence suggests that there is a pivotal role for physical force (mechanotransduction) in the initiation and/or the perpetuation of spondyloarthritis; the review contained herein examines that evidence. Furthermore, we know that damage and inflammation can limit spinal mobility, but is there a cycle created by altered spinal mobility leading to additional damage and inflammation?Over the past several years, mechanotransduction, the mechanism by which mechanical perturbation influences gene expression and cellular behaviour, has recently gained popularity because of emerging data from both animal models and human studies of the pathogenesis of ankylosing spondylitis (AS). In this review, we provide evidence towards an appreciation of the unsolved paradigm of how biomechanical forces may play a role in the initiation and propagation of AS.

Phytochemical Compounds Involved in the Bone Regeneration Process and Their Innovative Administration: A Systematic Review

Bone metabolism is a complex process which is influenced by the activity of bone cells (e.g., osteocytes, osteoblasts, osteoclasts); the effect of some specific biomarkers (e.g., parathyroid hormone, vitamin D, alkaline phosphatase, osteocalcin, osteopontin, osteoprotegerin, osterix, RANKL, Runx2); and the characteristic signaling pathways (e.g., RANKL/RANK, Wnt/β, Notch, BMP, SMAD). Some phytochemical compounds-such as flavonoids, tannins, polyphenols, anthocyanins, terpenoids, polysaccharides, alkaloids and others-presented a beneficial and stimulating effect in the bone regeneration process due to the pro-estrogenic activity, the antioxidant and the anti-inflammatory effect and modulation of bone signaling pathways. Lately, nanomedicine has emerged as an innovative concept for new treatments in bone-related pathologies envisaged through the incorporation of medicinal substances in nanometric systems for oral or local administration, as well as in nanostructured scaffolds with huge potential in bone tissue engineering.

Dual-analgesic loaded UHMWPE exhibits synergistic antibacterial effects against Staphylococci

Total joint arthroplasty is one of the most common surgeries in the United States, with almost a million procedures performed annually. Periprosthetic joint infections (PJI) remain the most devastating complications associated with total joint replacement. Effective antibacterial prophylaxis after primary arthroplasty could substantially reduce incidence rate of PJI. In the present study we propose to provide post-arthroplasty prophylaxis via dual-analgesic loaded ultra-high molecular weight polyethylene (UHMWPE). Our approach is based on previous studies that showed pronounced antibacterial activity of analgesic- and NSAID-loaded UHMWPE against Staphylococci. Here, we prepared bupivacaine/tolfenamic acid-loaded UHMWPE and assessed its antibacterial activity against Staphylococcus aureus and Staphylococcus epidermidis. Dual-drug loaded UHMWPE yielded an additional 1-2 log reduction of bacteria, when compared with single-drug loaded UHMWPE. Analysis of the drug elution kinetics suggested that the observed increase in antibacterial activity is due to the increased tolfenamic acid elution from dual-drug loaded UHMWPE. We showed that the increased fractal dimension of the drug domains in UHMWPE could be associated with increased drug elution, leading to higher antibacterial activity. Dual-analgesic loaded UHMWPE proposed here can be used as part of multi-modal antibacterial prophylaxis and promises substantial reduction in post-arthroplasty mortality and morbidity.

Effect of non-steroidal anti-inflammatory drugs on fracture healing in children: A systematic review

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most commonly prescribed medications in the United States. Although they are safe and effective means of analgesia for children with broken bones, there is considerable variation in their clinical use due to persistent concerns about their potentially adverse effect on fracture healing.

AIM

To assess whether NSAID exposure is a risk factor for fracture nonunion in children.

METHODS

We systematically reviewed the literature reporting the effect of NSAIDs on bone healing. We included all clinical studies that reported on adverse bone healing complications in children with respect to NSAID exposure. The outcomes of interest were delayed union or nonunion. Study quality was assessed using the Newcastle-Ottawa scale for non-randomized studies. A final table was constructed summarizing the available evidence.

RESULTS

A total of 120 articles were identified and screened, of which 6 articles were included for final review. Nonunion in children is extremely rare; among the studies included, there were 2011 nonunions among 238822 fractures (0.84%). None of the included studies documented an increased risk of nonunion or delayed bone healing in those children who are treated with NSAIDs in the immediate post-injury or peri-operative time period. Additionally, children are likely to take these medications for only a few days after injury or surgery, further decreasing their risk of adverse side-effects.

CONCLUSION

This systematic review suggests that NSAIDS can be safely prescribed to pediatric orthopaedic patients absent other contraindications without concern for increased risk of fracture non-union or delayed bone healing. Additional prospective studies are needed focusing on higher risk fractures and elective orthopaedic procedures such as osteotomies and spinal fusion.

How Do Drugs Affect the Skeleton? Implications for Forensic Anthropology

Simple Summary

Forensic anthropologists analyze human remains to assist in the identification of the deceased, predominantly by assessing age-at-death, sex, stature, ancestry and any unique identifying features. Whilst methods have been established to create this biological profile of the skeleton, these may be influenced by a number of factors. This paper, for the first time, provides an overview from a reading of the clinical and pharmacological literature to explore whether the intake of drugs can affect the skeleton and whether these may have implications for forensic anthropology casework. In effect, drugs such as tobacco, heroin, and prescription medications can alter bone mineral density, can increase the risk of fractures, destroy bone and changes to the dentition. By considering how drugs can affect the skeleton, forensic anthropologists can be aware of this when attempting to identify the deceased.

Abstract

Forensic anthropologists rely on a number of parameters when analyzing human skeletal remains to assist in the identification of the deceased, predominantly age-at-death, sex, stature, ancestry or population affinity, and any unique identifying features. During the examination of human remains, it is important to be aware that the skeletal features considered when applying anthropological methods may be influenced and modified by a number of factors, and particular to this article, prescription drugs (including medical and non-medical use) and other commonly used drugs. In view of this, this paper aims to review the medical, clinical and pharmacological literature to enable an assessment of those drug groups that as side effects have the potential to have an adverse effect on the skeleton, and explore whether or not they can influence the estimation of age-at-death, sex and other indicators of the biological profile. Moreover, it may be that the observation of certain alterations or inconsistencies in the skeleton may relate to the use of drugs or medication, and this in turn may help narrow down the list of missing persons to which a set of human remains could belong. The information gathered from the clinical and medical literature has been extracted with a forensic anthropological perspective and provides an awareness on how several drugs, such as opioids, cocaine, corticosteroids, non-steroidal anti-inflammatory drugs, alcohol, tobacco and others have notable effects on bone. Through different mechanisms, drugs can alter bone mineral density, causing osteopenia, osteoporosis, increase the risk of fractures, osteonecrosis, and oral changes. Not much has been written on the influence of drugs on the skeleton from the forensic anthropological practitioner perspective; and this review, in spite of its limitations and the requirement of further research, aims to investigate the current knowledge of the possible effects of both prescription and recreational drugs on bones, contributing to providing a better awareness in forensic anthropological practice and assisting in the identification process of the deceased.

Flunixin Meglumine Enhanced Bone Fracture Healing in Rabbits Associated with Activation of Early Collagen Deposition and Enhancement of Vascular Endothelial Growth Factor Expression

Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most commonly used postoperative analgesics, antipyretics, and anti-inflammatories, and they help prevent blood clotting. However, most NSAIDs delay bone healing. This study was aimed to investigate bone healing in a rabbit animal model by assessing the ability of flunixin meglumine (FM) and ketoprofen to induce fracture healing by examining histology, radiological changes, and vascular endothelial growth factor (VEGF) immunostaining during bone healing. For this purpose, 24 New Zealand rabbits were assigned to three groups: the control group, the FM group, and the ketoprofen group. Our results revealed that there were no intraoperative complications, and all surviving rabbits achieved full-weight bearing. Significant periosteal reaction and callus formation were confirmed at 2 postoperative weeks. Interestingly, FM enhanced callus formation, bone union, and remodeling in the FM group compared to the control and ketoprofen groups. FM enhanced bone healing through early collagen deposition and marked angiogenesis process activation by increasing the expression of VEGF. Our findings demonstrated, for the first time, the potential imperative action of FM in the bone healing process rather than other NSAIDs in animals.

Non-steroidal anti-inflammatory drugs and bone healing in animal models-a systematic review and meta-analysis

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAID) have excellent anti-inflammatory and analgesic properties and are extensively used to treat post-traumatic or surgical musculoskeletal pain. Although an extensive literature exists on the administration of NSAID on animal bone healing, no systematic review and meta-analysis of animal studies that investigate the effect of NSAID administration on bone fracture healing. Objective of this study is to conduct a systematic review and meta-analysis to estimate the effect of NSAIDs administration on bone healing biomechanical and histomorphometric measurements in different animal models after bone fracture surgery.

METHODS

We performed a systematic review and meta-analysis of animal studies to estimate the effect of NSAID administration after bone fracture on healing outcomes. We searched eight databases without limiting the search to starting date up to 1 February 2021 for articles on fractured bone healing in animal models in which NSAID were administered.

RESULTS

Out of 6732 articles screened, 47 were included and 3 common bone healing outcomes were analysed: biomechanical properties (maximum force to break, stiffness, and work-to-failure), micro-computed tomography (μ-CT), and histomorphometric measurements. The studies were generally of low-quality scores because crucial information, especially concerning randomization, blinding, and allocation concealment, was poorly reported. Our results show that the negative effects of NSAID after bone fracture on certain biomechanical properties of the healing bones was not statistically significant in mice compared with other animals, in females compared with males, and in younger compared with older animals.

CONCLUSION

The findings demonstrated that NSAIDs administration decreased the biomechanical properties of healing bones after fracture surgery in comparison to the control group. Moreover, different effect on certain outcomes was detected among different sites, sex of the animals, and the time of assessment.

TRIAL REGISTRATION

Protocol published and registered in SYstematic Review Center for Laboratory animal Experimentation (SYRCLE) in 2017, https://www.radboudumc.nl/getmedia/757ec408-7a9e-4635-8233-ae951effea54/Non-Steroidal-Anti-inflammatory-Drugs-and-bone-healing-in-animal-Models-Systematic-Review-and-Meta-Analysis.aspx.

Effects of NSAIDs on pre-osteoblast viability and osteogenic differentiation

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used in the treatment of a variety of musculoskeletal conditions, injuries and after surgery for postoperative pain management. Their use has been associated with impaired bone healing, possibly due to a multifactorial function, which may include inhibition of osteoblast recruitment and differentiation. However, up to date, there is no consensus regarding the impact of NSAIDs on bone-healing. The aim of the current study was to investigate the effects of five NSAIDs on the cellular functions of mouse MC3T3-E1 pre-osteoblasts. Cells were treated with the non-selective COX inhibitors lornoxicam and diclofenac, the COX-2 selective inhibitors parecoxib, meloxicam and paracetamol, as well as steroidal prednisolone at different doses and exposure times. The PrestoBlue™ technique was used to measure cell viability, an enzymatic assay was employed for alkaline phosphatase (ALP) activity and alizarin red S mineral staining was used to determine osteogenic differentiation. All drugs had a negative impact on pre-osteoblast cell growth, with the exception of paracetamol. Lornoxicam, diclofenac and meloxicam reduced ALP activity, while the other NSAIDs had no effect and prednisolone strongly increased ALP activity. In contrast, calcium deposits were either unaffected or increased by NSAID treatments but were significantly decreased by prednisolone. These results provide evidence that NSAIDs may adversely affect the viability of mouse pre-osteoblast cells but their actions on the osteogenic differentiation are drug-specific. The direct comparison of the effects of different NSAIDs and prednisolone on pre-osteoblasts may serve to place some NSAIDs in a preferential position for analgesic and anti-inflammatory therapy during bone repair.

Patient perception after oral biopsies: an observational outpatient study

OBJECTIVE

The aim of this study was to evaluate the postoperative course in patients undergoing oral mucosal biopsies, considering clinical and patient's perception variables potentially correlated to poor healing.

SUBJECTS AND METHODS

Eighty patients underwent oral biopsies. All the variables connected with the surgery were recorded, and the harvested volume was calculated through image software (ImageJ, NIH, Betesda, USA). To evaluate the postoperative discomfort, the OHIP-14 and the numeric rating scale of pain (NRS) were administered at 6 h, 7 days and 21 days after biopsy.

RESULTS

Six hours after the biopsy, 22 (OHIP-14 ≥ 20) and 24 (NRS ≥ 4) patients experienced a troublesome or painful healing, respectively. A significant statistical correlation between poor healing and high scores of NRS and OHIP was detected (Pearson's correlation test p < 0.05). Higher values of OHIP-14 were correlated to the type of lesion (OR = 1.165; p < 0.05), whereas high values of NRS were correlated to the use of systemic drugs (p < 0.05). No surgical variable had a significant statistical correlation with any of the outcomes.

CONCLUSIONS

The clinical evaluation was correlated with the patient's perception of pain and discomfort. This finding could be suggestive of the fact that wound healing can be reliably monitored with the help of these tools.

CLINICAL RELEVANCE

Patient perception can be a predictor of the healing of biopsied tissues.

The Effect of Diclofenac Sodium-Loaded PLGA Rods on Bone Healing and Inflammation: A Histological and Histomorphometric Study in the Femur of Rats

Implants made of poly(lactide-co-glycolide) (PLGA) are biodegradable and frequently provoke foreign body reactions (FBR) in the host tissue. In order to modulate the inflammatory response of the host tissue, PLGA implants can be loaded with anti-inflammatory drugs. The aim of this study was to analyze the impact of PLGA 80/20 rods loaded with the diclofenac sodium (DS) on local tissue reactions in the femur of rats. Special emphasis was put on bone regeneration and the presence of multinucleated giant cells (MGCs) associated with FBR. PLGA 80/20 alone and PLGA 80/20 combined with DS was extruded into rods. PLGA rods loaded with DS (PLGA+DS) were implanted into the femora of 18 rats. Eighteen control rats received unloaded PLGA rods. The follow-up period was of 3, 6 and 12 weeks. Each group comprised of six rats. Peri-implant tissue reactions were histologically and histomorphometrically evaluated. The implantation of PLGA and PLGA+DS8 rods induced the formation of a layer of newly formed bone islands parallel to the contour of the implants. PLGA+DS rods tended to reduce the presence of multi-nucleated giant cells (MGCs) at the implant surface. Although it is known that the systemic administration of DS is associated with compromised bone healing, the local release of DS via PLGA rods did not have negative effects on bone regeneration in the femora of rats throughout 12 weeks.

Prevalence and influencing factors of nonunion in patients with tibial fracture: systematic review and meta-analysis

OBJECTIVE

The aim of this study is to assess the prevalence of nonunion in patients with tibia fracture and the association between influencing factors and tibia fracture nonunion.

METHOD

A database searches of PubMed, the Cochrane Library, EMBASE, China National Knowledge Infrastructure (CNKI), Weipu database, and Wanfang database from inception until June 2019 was conducted. The pooled prevalence, odds ratio (OR), and 95% confidence intervals (CI) were calculated with Stata software.

RESULTS

In this study, 111 studies involving 41,429 subjects were included. In the study of the relationship between influencing factors and tibia fracture nonunion, 15 factors significantly influenced the fracture union, including > 60 years old, male, tobacco smoker, body mass index > 40, diabetes, nonsteroidal anti-inflammatory drugs (NSAIDs) user, opioids user, fracture of middle and distal tibia, high-energy fracture, open fracture, Gustilo-Anderson grade IIIB or IIIC, Müller AO Classification of Fractures C, open reduction, fixation model, and infection.

CONCLUSION

The prevalence of nonunion in patients with tibia fracture was 0.068 and 15 potential factors were associated with the prevalence. Closed reduction and minimally invasive percutaneous plate osteosynthesis (MIPPO) have the low risks of nonunion for the treatment of tibial fractures.

The effect of post-operative NSAID administration on bone healing after elective foot and ankle surgery

BACKGROUND

Post-operative pain is a common concern following elective foot and ankle surgery. NSAIDs used for pain relief have led to bone-healing complications in animal models and in vitro studies. This retrospective study examined the rate of bone-healing complications in post-surgical patients using NSAIDs.

METHODS

Participants underwent elective foot surgeries between January 2016 and May 2018. Radiographs were used to identify bony nonunion at osteotomy sites 12 weeks post-surgery.

RESULTS

Two-hundred thirty-two patients were evaluated; 59 (25.43%) were prescribed ibuprofen, 62 (27%) ketorolac, 15 (6.47%) acetaminophen, and 92 (40%) hydrocodone-acetaminophen. Two-hundred and twelve (91.38%) patients exhibited radiographic evidence of osseous union at 12 weeks and 20 (8.62%) had radiographic evidence of non-union of the osteotomy sites. There was no significant relationship between NSAID use and osseous non-union (p<0.05).

CONCLUSIONS

Short-term use of oral ibuprofen and ketorolac in the post-operative period was not associated with bony non-union.

Effect of Therapy on Radiographic Progression in Axial Spondyloarthritis: A Systematic Review and Meta-Analysis

OBJECTIVE

To investigate the effect of therapies on radiographic progression in patients with axial spondyloarthritis (SpA).

METHODS

A comprehensive database search for studies assessing radiographic progression in axial SpA (particular treatment versus no treatment of interest) was performed. Study-specific standardized mean differences in treatment outcomes at 2 and ≥4 years were estimated and combined using random-effects models.

RESULTS

Twenty-four studies in patients with axial SpA were identified, of which 18 involved tumor necrosis factor inhibitors (TNFi), 8 involved nonsteroidal antiinflammatory drugs (NSAIDs), and 1 involved secukinumab. Spinal radiographic progression, as measured by the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS), was not significantly different between TNFi-treated and biologics-naive patients at 2 years (mSASSS difference -0.73 [95% confidence interval (95% CI) -1.52, 0.12], I2 = 28%) and ≥4 years (mSASSS difference -2.03 [95% CI -4.63, 0.72], I2 = 63%). Sensitivity analyses restricted to studies with a low risk of bias showed a significant difference in spinal radiographic progression between TNFi-treated and biologics-naive patients at ≥4 years (mSASSS difference -2.17 [95% CI -4.19, -0.15]). No significant difference in spinal radiographic progression was observed between NSAID-treated and control patients (mSASSS difference -0.30 [95% CI -2.62, 1.31], I2 = 71%) or between secukinumab-treated and biologics-naive patients (mSASSS difference -0.34 [95% CI -0.85, 0.17]). With regard to treatment differences in patients with nonradiographic axial SpA or in patients with radiographic progression measured using the sacroiliac joint score, an insufficient number of studies were available for analysis.

CONCLUSION

Although no significant protective effect of TNFi treatment on spinal radiographic progression was seen over the course of 2 years or ≥4 years in patients with axial SpA, our analysis restricted to studies with a low risk of bias showed a protective effect of TNFi after ≥4 years. Therefore, long-term TNFi exposure might confer beneficial effects on spinal radiographic progression in axial SpA. No difference in radiographic progression at 2 years was seen in either the NSAID or secukinumab treatment groups compared to their controls. Future studies should explore the effects of biologic treatment on radiographic progression, as well as the effects of long-term biologics exposure, in patients with early axial SpA or those with nonradiographic axial SpA.

Influence of Ibuprofen on Bone Healing After Colles' Fracture: A Randomized Controlled Clinical Trial

Non-steroidal anti-inflammatory drugs (NSAIDs) may delay bone healing. [Therefore, it is important to establish whether NSAID preparations delay bone healing and what correlations, if any, exist between different bone studies-DEXA-scanning, bone markers, roentgenology controls, and histological examination of newly formed bone]. The purpose of this prospective controlled study was to investigate whether ibuprofen affects bone mineral density, turnover biomarkers, and histomorphometric characteristics of the callus after a Colles' fracture. This study was a single-center, triple-blinded, randomized clinical trial. Ninety-five patients (80 females) with displaced Colles' fracture, median age 65 (range 40-85) years were included in the study and operated on by external fixation from June 2012 through to June 2015. Eighty-nine patients received interventional medicine and 83 completed the 1-year follow-up. The 7-day ibuprofen group received 600 mg of ibuprofen three times a day (N = 29), the 3-day ibuprofen group received ibuprofen for 3 days (N = 30) and a placebo for the following 4 days, and finally, the placebo group received a placebo for 7 days (N = 30). The primary outcome was the difference in bone mineral density between the ultra-distal region of the injured and non-injured radius at 3 months after surgery. The histomorphometric outcomes included the assessment of callus tissue volume and surface fractions at 6 weeks postoperatively. The biomarkers Osteocalcin and CrossLaps were measured at baseline, 1 week, 2 weeks, 6 weeks, 3 months, and 1 year. We included the results of the dropped-out patients in the intention to treat analysis. There was no difference between treatment groups in bone mineral density, histomorphometric estimations, and changes in bone biomarkers. These findings may offer an indication of ibuprofen as a bone-safe analgesic treatment in an acute fracture-phase. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:545-554, 2020.

Heterotopic ossification: radiological and pathological review

Background Heterotopic Ossification (HO) is a common condition referring to ectopic bone formation in soft tissues. It has two major etiologies, acquired (more common) and genetic. The acquired form is closely related to tissue trauma. The exact pathogenesis of this disease remains unclear; however, there is ongoing research in prophylactic and therapeutic treatments that is promising. Conclusions Due to HO potential to cause disability, it is so important to differentiate it from other causes in order to establish the best possible management.

Effects of short- and long-term administration of nonsteroidal anti-inflammatory drugs on osteotomy healing in dogs

OBJECTIVE

To determine the influence of short-term administration of carprofen on bone healing in dogs.

STUDY DESIGN

Randomized controlled experimental study.

ANIMALS

Eighteen purpose-bred sexually mature hound dogs.

METHODS

Tibial osteotomies were performed, and dogs were divided into three groups: no carprofen (n = 6), 2-week administration of carprofen at 2.2 mg/kg twice daily (n = 6), and 8-week administration of carprofen at 2.2 mg/kg twice daily (n = 5). Bone healing was evaluated radiographically at 4 and 8 weeks postoperatively. Postmortem, fracture healing was assessed via biomechanical testing (three-point bending), histological cartilage:callus ratio, and bone mineral density (BMD) with quantitative computed tomography.

RESULTS

No biomechanical difference was detected between dogs that received no carprofen and those that received 2 weeks of carprofen or between those that received 2 weeks vs 8 weeks of carprofen. Stiffness (P = .035) and maximum stress (P = .042) were higher in dogs that received no carprofen than in those that received 8 weeks of carprofen. Radiographic healing did not differ between dogs without carprofen and those with 2-week administration of carprofen (P = .9923). However, tibias of dogs without carprofen and those with 2-week administration of carprofen were more healed compared with those in the 8-week-carprofen group at 4 and 8 weeks after surgery (P = .0011). No treatment effect was detected by cartilage:callus ratio or BMD.

CONCLUSION

Long-term administration of carprofen had a negative effect on bone healing compared with short-term or no administration of carprofen.

CLINICAL SIGNIFICANCE

Nonsteroidal anti-inflammatory drugs should be used cautiously in dogs at risk for delayed bone healing, and administration should be discontinued beyond the perioperative period in dogs with fractures or osteotomies.

Cytosolic group IVA phospholipase A2 inhibitors, AVX001 and AVX002, ameliorate collagen-induced arthritis

Background

Cytosolic phospholipase A2 group IVA (cPLA2α)-deficient mice are resistant to collagen-induced arthritis, suggesting that cPLA2α is an important therapeutic target. Here, the anti-inflammatory effects of the AVX001 and AVX002 cPLA2α inhibitors were investigated.

Methods

In vitro enzyme activity was assessed by a modified Dole assay. Effects on inhibiting IL-1β-induced release of arachidonic acid (AA) and prostaglandin E2 (PGE2) were measured using SW982 synoviocyte cells. In vivo effects were studied in prophylactic and therapetic murine collagen-induced arthritis models and compared to methotrexate (MTX) and Enbrel, commonly used anti-rheumatic drugs. The in vivo response to treatment was evaluated in terms of the arthritis index (AI), histopathology scores and by plasma levels of PGE2 following 14 and 21 days of treatment.

Results

Both cPLA2α inhibitors are potent inhibitors of cPLA2α in vitro. In synoviocytes, AVX001 and AVX002 reduce, but do not block, release of AA or PGE2 synthesis. In both CIA models, the AI and progression of arthritis were significantly lower in the mice treated with AVX001, AVX002, Enbrel and MTX than in non- treated mice. Several histopathology parameters of joint damage were found to be significantly reduced by AVX001 and AVX002 in both prophylactic and therapeutic study modes; namely articular cavity and peripheral tissue inflammatory cell infiltration; capillary and synovial hyperplasia; articular cartilage surface damage; and periostal and endochondral ossification. In comparison, MTX did not significantly improve any histopathology parameters and Enbrel only improved ossification. Finally, as a biomarker of inflammation and as an indication that AVX001 and AVX002 blocked the cPLA2α target, we determined that plasma levels of PGE2 were significantly reduced in response to the AVX inhibitors and MTX, but not Enbrel.

Conclusions

AVX001 and AVX002 display potent anti-inflammatory activity and disease-modifying properties in cellular and in vivo models. The in vivo effects of AVX001 and AVX002 were comparable to, or superior, to those of MTX and Enbrel. Taken together, this study suggests that cPLA2α inhibitors AVX001 and AVX002 are promising small molecule disease-modifying anti-rheumatic therapies.

Effect of the lipoxygenase inhibitor baicalein on bone tissue and bone healing in ovariectomized rats

BACKGROUND

Osteoporosis is one of the world's major medical burdens in the twenty-first century. Pharmaceutical intervention currently focusses on decelerating bone loss, but phytochemicals such as baicalein, which is a lipoxygenase inhibitor, may rescue bone loss. Studies evaluating the effect of baicalein in vivo are rare.

METHODS

We administered baicalein to sixty-one three-month-old female Sprague-Dawley rats. They were divided into five groups, four of which were ovariectomized (OVX) and one non-ovariectomized (NON-OVX). Eight weeks after ovariectomy, bilateral tibial osteotomy with plate osteosynthesis was performed and bone formation quantified. Baicalein was administered subcutaneously using three doses (C1: 1 mg/kg BW; C2: 10 mg/kg BW; and C3: 100 mg/kg BW) eight weeks after ovariectomy for four weeks. Finally, femora and tibiae were collected. Biomechanical tests, micro-CT, ashing, histological and gene expression analyses were performed.

RESULTS

Biomechanical properties were unchanged in tibiae and reduced in femora. In tibiae, C1 treatment enhanced callus density and cortical width and decreased callus area. In the C3 group, callus formation was reduced during the first 3 weeks after osteotomy, correlating to a higher mRNA expression of Osteocalcin, Tartrate-resistant acid phosphatase and Rankl. In femora, baicalein treatments did not alter bone parameters.

CONCLUSIONS

Baicalein enhanced callus density and cortical width but impaired early callus formation in tibiae. In femora, it diminished the biomechanical properties and calcium-to-phosphate ratio. Thus, it is not advisable to apply baicalein to treat early bone fractures. To determine the exact effects on bone healing, further studies in which baicalein treatments are started at different stages of healing are needed.

Repercussion of nonsteroidal anti-inflammatory drugs on the gene expression of human osteoblasts

Background

Nonsteroidal anti-inflammatory drugs (NSAIDs) are frequently used in clinical practice, which can have adverse effects on the osteoblast. The objective of this study was to determine the effect of NSAIDs on the osteoblast by analyzing the gene expression of different markers related to osteoblast maturation and function when treated in vitro with different NSAIDs.

Methods

Three human osteoblast lines from bone samples of three healthy volunteers were treated with 10 µM acetaminophen, indomethacin, ketoprofen, diclofenac, ibuprofen, ketorolac, naproxen, and piroxicam. The gene expression of different markers (run related transcription factor 2 [RUNX-2], type 1 collagen [COL-I], osterix [OSX], osteocalcin [OSC], bone morphogenetic protein 2 [BMP-2] and 7 [BMP-7], transforming growth factor β1 [TGF-β1], and TGFβ receptors [TGFβR1, TGFβR2; TGFBR3]) were analyzed by real-time PCR at 24 h of treatment.

Results

Expression of RUNX-2, COL-I, OSX, was reduced by treatment with all studied NSAIDs, OSC expression was reduced by all NSAIDs except for ketoprofen, naproxen, or piroxicam. Expression of BMP-7 was reduced by all NSAIDs; BMP-2 was reduced by all except for naproxen. In general, NSAID treatment increased the expression of TGF-β1, but not of its receptors (TGFβ-R1, TGFβ-R2, andTFGβ-R3), which was either unchanged or reduced by the treatment.

Conclusion

These data confirm that NSAIDs can affect osteoblast physiology, suggesting their possible impact on bone.

Positives and negatives of nonsteroidal anti-inflammatory drugs in bone healing: the effects of these drugs on bone repair

Tissue damage following injury triggers the processes of coagulation, inflammation and healing. In tissues surrounding the bone, the result of the healing process is a scar, while bone tissue has a unique ability to achieve shape, strength and pre-injury function. Bone healing is a process of regeneration rather than classic recovery. The result of this process is the formation of new, healthy bone tissue instead of a scar. Many factors can inhibit or impair the bone healing process, and their influence is critical during the stages of inflammation and angiogenesis and finally on the clinical outcome. Nonsteroidal anti-inflammatory drugs (NSAIDs) play an essential role associated with their analgesic potency and anti-inflammatory effects. NSAIDs are also the most often used drugs in patients who require pain control and inflammation reduction due to musculoskeletal diseases or injures. Although their analgesic effect is well documented, NSAIDs also interfere with bone healing; therefore, the relative benefits and disadvantages connected with their administration should be taken into consideration. Despite the negative effect, NSAIDs have beneficial properties, but their clinical benefits in relation to dose and time of use are still unclear. Therefore, in this review, we focus on bone healing with relation to the impact of NSAIDs.

Effects of Nonsteroidal Anti-Inflammatory Drugs at the Molecular Level

Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used for their anti-inflammatory, analgesic, and antipyretic effects. NSAIDs generally work by blocking the production of prostaglandins (PGs) through the inhibition of two cyclooxygenase enzymes. PGs are key factors in many cellular processes, such as gastrointestinal cytoprotection, hemostasis and thrombosis, inflammation, renal hemodynamics, turnover of cartilage, and angiogenesis. Interest has grown in the various effects of NSAIDs during the last decade. Epidemiological studies have revealed the reduced risk of several cancer types and neurodegenerative diseases by prolonged use of NSAIDs. Recent advances in the understanding of the cellular and molecular mechanisms of NSAIDs will accelerate the processes of discovery and clinical implementation. This review summarizes the molecular mechanisms of NSAIDs on the body systems.

Local infiltration analgesia: a 2-year follow-up of patients undergoing total hip arthroplasty

Purpose

Local infiltration analgesia (LIA) is commonly used for postoperative pain management following total hip arthroplasty (THA). However, the long-term effects of the component drugs are unclear. The aim of our study was to investigate functional outcome, quality of life, chronic post-surgical pain, and adverse events in patients within 2 years of undergoing THA.

Methods

The study was a secondary analysis of data from a previous larger study. Eighty patients were randomized to receive either intrathecal morphine (Group ITM) or local infiltration analgesia (Group LIA) for pain management in a double-blind study. The parameters measured were patient-assessed functional outcome [using the Hip dysfunction and Osteo-arthritis Outcome Score (HOOS) questionnaire], health-related quality of life [using the European Quality of Life–5 dimensions (EQ-5D) questionnaire and the 36-Item Short Form Health Survey (SF-36) score], and pain using the numeric rating score (NRS), with persistent post-surgical pain having a NRS of > 3 or a HOOS pain sub-score of > 30. All complications and adverse events were investigated during the first 2 years after primary surgery.

Results

Pain intensity and rescue analgesic consumption were similar between the groups after hospital discharge. No differences were found in HOOS or SF-36 score between the groups up to 6 months after surgery. A significant group × time interaction was seen in the EQ 5D form in favor of the LIA group. No between-group difference in persistent post-surgical pain was found at 3 or 6 months, or in adverse events up to 2 years after surgery.

Conclusion

Analysis of functional outcome, quality of life, and post-discharge surgical pain did not reveal significant differences between patients receiving LIA and those receiving ITM. LIA was found to be a safe technique for THA during the long-term follow-up. However, it should be noted that these conclusions are based on a limited number of patients.

The effect of NSAIDs on spinal fusion: a cross-disciplinary review of biochemical, animal, and human studies

PURPOSE

Non-steroidal anti-inflammatory drugs (NSAIDs) play an important role in postoperative pain management. However, their use in the setting of spine fusion surgery setting has long been a topic of controversy. In this review we examined relevant research, including in vivo, animal, and clinical human studies, with the aim of understanding the effect of NSAIDs on spinal fusion.

STUDY DESIGN/SETTING

Systematic review of study designs of all types from randomized controlled trials and meta-analyses to single-institution retrospective reviews.

METHODS

A search of PubMed and Embase was conducted using the keywords: "spine," "spinal fracture," NSAIDs, anti-inflammatory non-steroidal agents, bone, bone healing, fracture, fracture healing, yielding a total of 110 studies. Other 28 studies were identified by cross-referencing, resulting in total 138 studies.

RESULTS

There is no level I evidence from human studies regarding the use of NSAIDs on spinal fusion rates. The overall tone of the spine literature in the early 2000s was that NSAIDs increased the rate of non-union; however, nearly all human studies published after 2005 suggest that short-term (<2 weeks) postoperative use have no such effect. The dose dependency that is seen with a 2-week postoperative course is not present when NSAIDs are only used for 48 h after surgery.

CONCLUSIONS

NSAID appear to have dose-dependent and duration-dependent effects on fusion rates. The short-term use of low-dose NSAIDs around the time of spinal fusion surgery is reasonable. Spine surgeons can consider the incorporation of NSAIDs into pain control regimens for spinal fusion patients with the goal of improving pain control and reducing the costs and complications associated with opioids.

Chronic Osteoporotic Pain in Mice: Cutaneous and Deep Musculoskeletal Pain Are Partially Independent of Bone Resorption and Differentially Sensitive to Pharmacological Interventions

Although the pathological changes in osteoporotic bones are well established, the characterization of the osteoporotic pain and its appropriate treatment are not fully elucidated. We investigated the behavioral signs of cutaneous and deep musculoskeletal pain and physical function; time-dependent changes in bone mineral density (BMD) and the emergence of the behavioral phenotype; and the effects of pharmacological interventions having different mechanisms of action (chronic intraperitoneal administration of pamidronate [0.25 mg/kg, 5x/week for 5 weeks] versus acute treatment with intraperitoneal morphine [10 mg/kg] and pregabalin [100 mg/kg]) in a mouse model of ovariectomized or sham-operated mice 6 months following surgery. We observed reduced BMD associated with weight gain, referred cutaneous hypersensitivity, and deep musculoskeletal pain that persisted for 6 months. Chronic bisphosphonate treatment, 6 months after ovariectomy, reversed bone loss and hypersensitivity to cold, but other behavioral indices of osteoporotic pain were unchanged. While the efficacy of acute morphine on cutaneous pain was weak, pregabalin was highly effective; deep musculoskeletal pain was intractable. In conclusion, the reversal of bone loss alone is insufficient to manage pain in chronic osteoporosis. Additional treatments, both pharmacological and nonpharmacological, should be implemented to improve quality of life for osteoporosis patients.

Impact of Dose Tapering of Tumor Necrosis Factor Inhibitor on Radiographic Progression in Ankylosing Spondylitis

Objective

To investigate the impact of dose reduction of tumor necrosis factor inhibitor (TNFi) on radiographic progression in ankylosing spondylitis (AS).

Methods

One hundred and sixty-five patients treated with etanercept or adalimumab were selected from a consecutive single-center observational cohort based on the availability of radiographs at baseline and after two- and/or four-years of follow up. Radiographs were assessed by two blinded readers using the modified Stokes AS Spinal Score (mSASSS). Radiographic progression in patients treated with standard-dose TNFi (standard-dose group, n = 49) was compared with patients whose dosage was tapered during the treatment (tapering group, n = 116) using linear mixed models.

Results

Baseline characteristics between two groups were comparable except for higher BASDAI (7.1 vs. 6.3, p = 0.003) in the standard-dose group. At two years after the treatment, mean dose quotient (S.D.) of the tapering group was 0.59 (0.17). During follow up, rate of radiographic progression in overall patients was 0.90 mSASSS units/year. Radiographic progression over time between the two groups was similar at the entire group level. However, in the subgroup of patients with baseline syndesmophytes, progression occurred significantly faster in the tapering group after the adjustment for baseline status (1.23 vs. 1.72 mSASSS units/year, p = 0.023). Results were consistent when radiographic progression was assessed by the number of newly developed syndesmophytes (0.52 vs. 0.73/year, p = 0.047). Sensitivity analysis after multiple imputation of missing radiographs also showed similar results.

Conclusion

A dose tapering strategy of TNFi is associated with more rapid radiographic progression in AS patients who have syndesmophytes at baseline.

Comparative clinical study of the prophylaxis of heterotopic ossifications after total hip arthroplasty using etoricoxib or diclofenac

PURPOSE

This study investigated whether etoricoxib (COX-II blocker) has a superior efficacy of preventing heterotopic ossification (HO) after total hip arthroplasty (THA) compared to diclofenac (non-selective NSAID).

METHODS

One hundred patients were included (50 in each group) in this single centre, prospective, double-blinded, randomized, controlled trial. Etoricoxib (90 mg) was administered once and diclofenac (75 mg) twice per day for a perioperative period of nine days. The incidence of HO was evaluated on radiographs of the pelvis six months after surgery.

RESULTS

Eighty nine of 100 (89 %) patients could be analysed. The overall HO incidence was 37.8 %. There was no significant difference between both study groups. Twelve patients (27.3 %) of the DIC group and 13 patients (28.9 %) of the ETO group showed Brooker grade I ossifications. Five patients (11.4 %) of the DIC and four patients of the ETO (8.9 %) group showed grade II HO formations. No class III or IV HO formations occured in both groups. Ad hoc analysis detected a negative correlation between HO incidence and limited abduction and internal rotation of the hip.

CONCLUSIONS

Etoricoxib and diclofenac are equally effective for oral HO prophylaxis after primary cementless THA when given for nine peri-operative days to ensure a full recovery and high patient satisfaction.

Use and abuse of medication during 2014 FIFA World Cup Brazil: a retrospective survey

OBJECTIVE

To examine the use of medication of top-level male players during the 2014 FIFA World Cup Brazil.

DESIGN

Retrospective survey.

PARTICIPANTS/INFORMATION

736 top level players.

SETTING

The teams' physicians disclosed a list of the medications used by each player within 72 h before each match of the 2014 FIFA World Cup Brazil.

OUTCOME MEASURES

Average number of medications used per player per match or during the tournament; average number and percentage of players using at least one medication per match or during the tournament.

RESULTS

67.0% of all players took various types of medication during the tournament. The most used medications during the tournament were non-steroidal anti-inflammatory drugs (NSAIDs), by 54.2% of all players, followed by analgaesics (12.6%); β-2 agonists were only used by 0.5%. On average, 0.8 medications per player were used before each match. More players were reported taking medications during the knockout round than during the qualification round (0.36±0.48 vs 0.49±0.50, p<0.001). Players from the South American and Asian Confederations took twice as many medications per match as players from the African Confederation (1.17±1.55 and 1.01±1.26 vs 0.48±0.69, both p<0.001).

CONCLUSIONS

There was high use of NSAIDs during the 2014 FIFA World Cup. Although the intake of NSAIDs per match (0.35±0.46 vs 0.31±0.48, p<0.01) in the 2014 FIFA World Cup decreased compared to the 2010 FIFA World Cup, the average use was still higher than in the 2006 FIFA World Cup, and the average number of all used medications per player remained the same level as 4 years prior, with all its implications for the player's health. More efforts need to be undertaken worldwide in order to reduce the administration of medications in sports, through continuous education for players, starting from a young age, as well as for doctors and paramedics.

Heterotopic Ossification: Basic-Science Principles and Clinical Correlates

➤ Heterotopic ossification occurs most commonly after joint arthroplasty, spinal cord injury, traumatic brain injury, blast trauma, elbow and acetabular fractures, and thermal injury.➤ The conversion of progenitor cells to osteogenic precursor cells as a result of cell-mediated interactions with the local tissue environment is affected by oxygen tension, pH, availability of micronutrients, and mechanical stimuli, and leads to heterotopic ossification.➤ Radiation and certain nonsteroidal anti-inflammatory medications are important methods of prophylaxis against heterotopic ossification.➤ Well-planned surgical excision can improve patient outcomes regardless of the joint involved or the initial cause of injury.➤ Future therapeutic strategies are focused on targeted inhibition of local factors and signaling pathways that catalyze ectopic bone formation.

Incidence and clinical relevance of heterotopic ossification after internal fixation of acetabular fractures: retrospective cohort and case control study

Objective

The aim of the study was to evaluate predictors and clinical relevance of heterotopic ossification (HO) in patients treated for acetabular fractures in a tertiary referral centre.

Patients and methods

The study is a retrospective cohort study with a nested case–control study. All patients treated with internal fixation of acetabular fractures from January 2004 to October 2013. Ninety patients had postoperative imaging available at 6 and 12 months postoperatively and received no prophylaxis. Plain radiographs were used to grade HO. The Hip disability and Osteoarthritis Outcome Score (HOOS) was used to compare outcomes between patients suffering from HO with patients who did not.

Results

Sixteen patients (17.7%) suffered from HO. According to the Brooker classification, 5 had class I, 4 class II, 3 class III and 4 class IV HO. Traumatic brain injury (TBI) was the only significant risk factor for developing HO (odds ratio (OR) 8.6, 95% confidence interval (CI) (1.693–43.753), p = 0.014). The HO rate in patients with an anterior (ilioinguinal) or posterior (Kocher-Langenbeck) surgical approach was 20% and 21% respectively, and the HO rate in patients with a combined approach was much lower at 11%. Neither fracture type nor gender nor age increased the risk of HO significantly. The outcome measured by HOOS was not significantly different between patients with HO and patients in the control group. Patients with HO Brooker class II–IV had slightly lower (effect estimate +4.25, 95% CI (−10.2 to +12.10), p = 0.220) HOOS compared to the majority of the control group.

Conclusion

A very low rate of HO was found compared to the HO rates described in other studies with similar patient cohorts who received prophylaxis. Based on our findings and the current literature, we do not recommend giving prophylaxis against HO to patients after internal fixation of acetabular fractures.

Naproxen affects osteogenesis of human mesenchymal stem cells via regulation of Indian hedgehog signaling molecules

INTRODUCTION

We previously showed that type X collagen, a marker of late stage chondrocyte hypertrophy (associated with endochondral ossification), is constitutively expressed by mesenchymal stem cells (MSCs) from osteoarthritis patients and this may be related to Naproxen (Npx), a nonsteroidal anti-inflammatory drug used for therapy. Hedgehog (HH) signaling plays an important role during the development of bone. We tested the hypothesis that Npx affected osteogenic differentiation of human MSCs through the expression of Indian hedgehog (IHH), Patched-1 (PTC1) and GLI family members GLI1, GLI2, GLI3 in vitro.

METHODS

MSCs were cultured in osteogenic differentiation medium without (control) or with 0.5 μM Npx. The expression of collagen type X, alpha 1 (COL10A1), alkaline phosphatase (ALP), osteopontin (OPN), osteocalcin (OC), collagen type I, alpha 1 (COL1A1) was analyzed with real-time reverse transcription (RT) PCR, and the ALP activity was measured. The osteogenesis of MSCs was monitored by mineral staining and quantification with alizarin red S. To examine whether Npx affects osteogenic differentiation through HH signaling, the effect of Npx on the expression of IHH, GLI1, GLI2, GLI3 and PTC1 was analyzed with real-time RT PCR. The effect of cyclopamine (Cpn), a HH signaling inhibitor, on the expression of COL10A1, ALP, OC and COL1A1 was also determined.

RESULTS

When MSCs were cultured in osteogenic differentiation medium, Npx supplementation led to a significant decrease in ALP gene expression as well as its activity, and had a tendency to decrease mineral deposition. It also decreased the expression of COL1A1 significantly. In contrast, the gene expression of COL10A1 and OPN were upregulated significantly by Npx. No significant effect was found on OC expression. The expression of IHH, PTC1, GLI1, and GLI2 was increased by Npx, while no significant difference was observed on GLI3 expression. Cpn reversed the effect of Npx on the expression of COL10A1, ALP, OPN and COL1A1.

CONCLUSIONS

These results indicate that Npx can affect gene expression during osteogenic differentiation of MSCs, and downregulate mineral deposition in the extracellular matrix through IHH signaling. Therefore, Npx could affect MSC-mediated repair of subchondral bone in OA patients.

Cytosolic phospholipase A2 regulates TNF-induced production of joint destructive effectors in synoviocytes

INTRODUCTION

Rheumatoid arthritis (RA) is an inflammatory disease of the joint characterized by chronic synovitis causing pain, swelling and loss of function due to destruction of cartilage and bone. The complex series of pathological events occurring in RA is largely regulated via excessive production of pro-inflammatory cytokines, the most prominent being tumor necrosis factor (TNF). The objective of this work was to elucidate possible involvement of group IVA cytosolic phospholipase A2 (cPLA2α) in TNF-induced regulation of synovitis and joint destructive effectors in RA, to evaluate the potential of cPLA2α as a future therapeutic target.

METHODS

The involvement of cPLA2α in tumor necrosis factor (TNF)-induced intracellular signaling cascades in synoviocytes (synovial fibroblast-like cells) was analyzed by arachidonic acid (AA) release assay, synoviocyte enzyme activity assay, gene expression analysis by real-time PCR and ELISA immunoassay for the detection of prostaglandin E2 (PGE2), interleukin 8 (IL8) and stromelysin-1 (MMP3), respectively.

RESULTS

Inhibitors of cPLA2α enzyme activity (AVX002, ATK) significantly reduced TNF-induced cellular release of AA, PGE2, IL8 and MMP3. This reduction was evident both at transcriptional, protein or metabolite levels. Interestingly, cPLA2α inhibition affected several key points of the arachidonyl cascade; AA-release, cyclooxygenase-2 (COX2) expression and PGE2 production. Furthermore, the results suggest that cPLA2α is subject to transcriptional auto-regulation as inhibition of cPLA2α resulted in reduced PLA2G4A gene expression in TNF-stimulated synoviocytes.

CONCLUSIONS

cPLA2α appears to be an important regulator of central effectors of inflammation and joint destruction, namely MMP3, IL8, COX2, and PGE2. Decreased transcription of the PLA2G4A and COX2 genes in response to cPLA2α enzyme inhibition further suggest a self-reinforcing effect of cPLA2α inhibition in response to TNF. Collectively, these results support that cPLA2α is an attractive therapeutic target candidate as its inhibition reduces the production of multiple key pro-inflammatory factors involved in RA pathogenesis.

Therapeutic doses of nonsteroidal anti-inflammatory drugs inhibit osteosarcoma MG-63 osteoblast-like cells maturation, viability, and biomineralization potential

Nonsteroidal anti-inflammatory drugs (NSAIDs) are frequently used to reduce pain and inflammation. However, their effect on bone metabolisms is not well known, and results in the literature are contradictory. The present study focusses on the effect of dexketoprofen, ketorolac, metamizole, and acetylsalicylic acid, at therapeutic doses, on different biochemical and phenotypic pathways in human osteoblast-like cells. Osteoblasts (MG-63 cell line) were incubated in culture medium with 1-10 μM of dexketoprofen, ketorolac, metamizole, and acetylsalicylic acid. Flow cytometry was used to study antigenic profile and phagocytic activity. The osteoblastic differentiation was evaluated by mineralization and synthesis of collagen fibers by microscopy and alkaline phosphatase activity (ALP) by spectrophotometric assay. Short-term treatment with therapeutic doses of NSAIDs modulated differentiation, antigenic profile, and phagocyte activity of osteoblast-like cells. The treatment reduced ALP synthesis and matrix mineralization. However, nonsignificant differences were observed on collagen syntheses after treatments. The percentage of CD54 expression was increased with all treatments. CD80, CD86, and HLA-DR showed a decreased expression, which depended on NSAID and the dose applied. The treatments also decreased phagocyte activity in this cellular population. The results of this paper provide evidences that NSAIDs inhibit the osteoblast differentiation process thus reducing their ability to produce new bone mineralized extracellular matrix.

Ketorolac administration does not delay early fracture healing in a juvenile rat model: a pilot study

BACKGROUND

Nonsteroidal anti-inflammatory drugs (NSAIDs) are effective at controlling pain in children, especially in the treatment of fractures. Adult animal and adult clinical studies demonstrate conflicting evidence for the inhibitory relationship between NSAIDs and fracture healing. Published pediatric orthopaedic clinical studies do not demonstrate an inhibitory effect of ketorolac on bone healing. Little is known about the effects of any NSAID on bone formation in juvenile animals. This study investigates the effects of the NSAID ketorolac on fracture healing in a juvenile rat model.

METHODS

Unilateral surgically induced and stabilized tibial shaft fractures were created in 45 juvenile (3 to 4 wk old) male Sprague-Dawley rats. Either ketorolac (5 mg/kg; n=24) or saline (0.9% normal saline; n=21) was then administered to the rats 6 d/wk by intraperitoneal injections. Animals were then randomly assigned into time groups and euthanized at 7 days (n=8 ketorolac, n=7 saline), 14 days (n=8 ketorolac, n=7 saline), or 21 days (n=8 ketorolac, n=7 saline) postfracture. Biomechanical analysis was performed using a custom-designed 4-point bending loading apparatus. Statistics for tibial stiffness and strength data were performed using software package Systat 11. Specimens were also evaluated histologically using hematoxylin and eosin staining.

RESULTS

Strength and stiffness of all fractured tibiae increased over time from day 7 to day 21 regardless of treatment type. No statistical difference was found between the fractured tibiae strength or stiffness in the ketorolac or control-treated specimens at the same time point. In addition, the quality of the fracture callus was similar in both groups at each of the time points.

CONCLUSIONS

In this study of a juvenile rat model with a stabilized tibia fracture, fracture callus strength, stiffness, and histologic characteristics were not affected by the administration of ketorolac during the first 21 days of fracture healing.

CLINICAL RELEVANCE

The absence of inhibitory effects of ketorolac on early juvenile rat fracture healing supports the clinical practice of utilizing NSAIDs for analgesia in children with long bone fractures.

E-type prostanoid receptor 4 (EP4) in disease and therapy

The large variety of biological functions governed by prostaglandin (PG) E2 is mediated by signaling through four distinct E-type prostanoid (EP) receptors. The availability of mouse strains with genetic ablation of each EP receptor subtype and the development of selective EP agonists and antagonists have tremendously advanced our understanding of PGE2 as a physiologically and clinically relevant mediator. Moreover, studies using disease models revealed numerous conditions in which distinct EP receptors might be exploited therapeutically. In this context, the EP4 receptor is currently emerging as most versatile and promising among PGE2 receptors. Anti-inflammatory, anti-thrombotic and vasoprotective effects have been proposed for the EP4 receptor, along with its recently described unfavorable tumor-promoting and pro-angiogenic roles. A possible explanation for the diverse biological functions of EP4 might be the multiple signaling pathways switched on upon EP4 activation. The present review attempts to summarize the EP4 receptor-triggered signaling modules and the possible therapeutic applications of EP4-selective agonists and antagonists.

Immune and inflammatory pathways are involved in inherent bone marrow ossification

BACKGROUND

Bone marrow plays a key role in bone formation and healing. Although a subset of marrow explants ossifies in vitro without excipient osteoinductive factors, some explants do not undergo ossification. The disparity of outcome suggests a significant heterogeneity in marrow tissue in terms of its capacity to undergo osteogenesis.

QUESTIONS/PURPOSES

We sought to identify: (1) proteins and signaling pathways associated with osteogenesis by contrasting the proteomes of ossified and poorly ossified marrow explants; and (2) temporal changes in proteome and signaling pathways of marrow ossification in the early and late phases of bone formation.

METHODS

Explants of marrow were cultured. Media conditioned by ossified (n = 4) and poorly ossified (n = 4) subsets were collected and proteins unique to each group were identified by proteomic analysis. Proteomic data were processed to assess proteins specific to the early phase (Days 1-14) and late phase (Days 15-28) of the culture period. Pathways involved in bone marrow ossification were identified through bioinformatics.

RESULTS

Twenty-eight proteins were unique to ossified samples and eight were unique to poorly ossified ones. Twelve proteins were expressed during the early phase and 15 proteins were specific to the late phase. Several identified pathways corroborated those reported for bone formation in the literature. Immune and inflammatory pathways were specific to ossified samples.

CONCLUSIONS

The marrow explant model indicates the inflammatory and immune pathways to be an integral part of the osteogenesis process.

Effect of ibuprofen on proliferation, differentiation, antigenic expression, and phagocytic capacity of osteoblasts

Ibuprofen is a nonselective nonsteroidal antiinflammatory drug commonly prescribed for acute postsurgical and posttraumatic pain. However, little known is about the effect of this drug on osteoblasts. In this study, we aimed to investigate the effect of ibuprofen on cell proliferation, differentiation, antigenic profile, and phagocytic activity, in a human MG-63 osteosarcoma cell line, as a model of osteoblasts. Flow cytometry was used to study proliferation, antigenic profile, and phagocytic activity, and radioimmunoassay was used to determine osteocalcin synthesis as a cell differentiation marker. Our results showed that therapeutic doses of ibuprofen (5 and 25 μM) did not modify cell proliferation and osteocalcin synthesis in the MG-63 cellular line. However, treatment with a higher dose (25 μM) increased the expression of antigens CD21, CD44, CD80, CD86, and HLA-DR and decreased phagocytic activity. The results indicate that a therapeutic dose of ibuprofen has no adverse effects on growth of the osteoblast-like cells. Treatment with ibuprofen alone may produce some cell activation, which would explain the increase in expression of membrane markers and decrease in phagocytic capacity.

Targeting polymer therapeutics to bone

An aging population in the developing world has led to an increase in musculoskeletal diseases such as osteoporosis and bone metastases. Left untreated many bone diseases cause debilitating pain and in the case of cancer, death. Many potential drugs are effective in treating diseases but result in side effects preventing their efficacy in the clinic. Bone, however, provides a unique environment of inorganic solids, which can be exploited in order to effectively target drugs to diseased tissue. By integration of bone targeting moieties to drug-carrying water-soluble polymers, the payload to diseased area can be increased while side effects decreased. The realization of clinically relevant bone targeted polymer therapeutics depends on (1) understanding bone targeting moiety interactions, (2) development of controlled drug delivery systems, as well as (3) understanding drug interactions. The latter makes it possible to develop bone targeted synergistic drug delivery systems.

A soluble factor from Trypanosoma cruzi inhibits transforming growth factor-ß-induced MAP kinase activation and gene expression in dermal fibroblasts

The protozoan parasite Trypanosoma cruzi, which causes human Chagas' disease, exerts a variety of effects on host extracellular matrix (ECM) including proteolytic degradation of collagens and dampening of ECM gene expression. Exposure of primary human dermal fibroblasts to live infective T. cruzi trypomastigotes or their shed/secreted products results in a rapid down-regulation of the fibrogenic genes collagenIα1, fibronectin and connective tissue growth factor (CTGF/CCN2). Here we demonstrate the ability of a secreted/released T. cruzi factor to antagonize ctgf/ccn2 expression in dermal fibroblasts in response to TGF-ß, lysophosphatidic acid or serum, where agonist-induced phosphorylation of the mitogen-activated protein (MAP) kinases Erk1/2, p38 and JNK was also inhibited. Global analysis of gene expression in dermal fibroblasts identified a discrete subset of TGF-ß-inducible genes involved in cell proliferation, wound repair, and immune regulation that are inhibited by T. cruzi secreted/released factors, where the genes exhibiting the highest sensitivity to T. cruzi are known to be regulated by MAP kinase-activated transcription factors. Consistent with this observation, the Ets-family transcription factor binding site in the proximal promoter region of the ctgf/ccn2 gene (−91 bp to −84 bp) was shown to be required for T. cruzi-mediated down-regulation of ctgf/ccn2 reporter expression. The cumulative data suggest a model in which T. cruzi-derived molecules secreted/released early in the infective process dampen MAP kinase signaling and the activation of transcription factors that regulate expression of fibroblast genes involved in wound repair and tissue remodelling, including ctgf/ccn2. These findings have broader implications for local modulation of ECM synthesis/remodelling by T. cruzi during the early establishment of infection in the mammalian host and highlight the potential for pathogen-derived molecules to be exploited as tools to modulate the fibrogenic response.

Infection, inflammation, and bone regeneration: a paradoxical relationship

Various strategies have been developed to promote bone regeneration in the craniofacial region. Most of these interventions utilize implantable materials or devices. Infections resulting from colonization of these implants may result in local tissue destruction in a manner analogous to periodontitis. This destruction is mediated via the expression of various inflammatory mediators and tissue-destructive enzymes. Given the well-documented association among microbial biofilms, inflammatory mediators, and tissue destruction, it seems reasonable to assume that inflammation may interfere with bone healing and regeneration. Paradoxically, recent evidence also suggests that the presence of certain pro-inflammatory mediators is actually required for bone healing. Bone injury (e.g., subsequent to a fracture or surgical intervention) is followed by a choreographed cascade of events, some of which are dependent upon the presence of pro-inflammatory mediators. If inflammation resolves promptly, then proper bone healing may occur. However, if inflammation persists (which might occur in the presence of an infected implant or graft material), then the continued inflammatory response may result in suboptimal bone formation. Thus, the effect of a given mediator is dependent upon the temporal context in which it is expressed. Better understanding of this temporal sequence may be used to optimize regenerative outcomes.

Emerging ideas: can erythromycin reduce the risk of aseptic loosening?

BACKGROUND

Persistent inflammatory reaction to wear debris causes periprosthetic osteolysis and loosening. Some authors have advocated pharmaceutical approaches to reduce the inflammatory reaction. Erythromycin has antiinflammatory effects independent of its antimicrobial properties. Although oral erythromycin reportedly inhibits periprosthetic tissue inflammation in patients with aseptic loosening, long-term systematic erythromycin treatment is not recommended owing to its side effects. Therefore, it would be advantageous to restrict erythromycin delivery to the inflammatory periprosthetic tissue without causing side effects.

QUESTIONS/HYPOTHESES

Erythromycin eluted from hydroxyapatite-coated titanium (Ti) pins inhibits periprosthetic tissue inflammation and osteolysis.

METHOD OF STUDY

We propose restricting erythromycin delivery to the inflammatory periprosthetic site. A previously described rat model of ultrahigh molecular weight polyethylene (UHMWPE) particle-induced periprosthetic tissue inflammation and osteolysis will be used to test the effect of local delivery of erythromycin via Peri-Apatite(TM)-coated Ti implants. The outcome measures will include bone ingrowth (μCT), implant stability (pullout test), and histologic analysis of periprosthetic tissues.

SIGNIFICANCE

Pharmacologic intervention aimed at slowing, preventing, or reversing the aseptic loosening process would represent an advance in the management of joint replacement. Erythromycin may be appropriate for prophylactically treating patients who have repeated revision surgery and/or show early signs of progressive osteolysis after arthroplasty.

Use of proton pump inhibitors and risk of hip/femur fracture: a population-based case-control study

Previous studies evaluated the association between proton pump inhibitor (PPI) use and subsequent fracture risk, but they showed ambiguous results. Therefore, the objective was to evaluate this association in a different study population. Our findings show that there is probably no causal relationship between PPI use and hip fracture risk.

INTRODUCTION

Previous studies evaluated the association between PPI use and subsequent fracture risk, but they showed ambiguous results. To further test these conflicting results, the objective of this study was to evaluate the association between the use of PPIs and the risk of hip/femur fracture in a different study population.

METHODS

A case-control study was conducted using data from the Dutch PHARMO record linkage system. The study population included 6,763 cases aged 18 years and older with a first hip/femur fracture during enrollment and 26,341 age-, gender- and region-matched controls.

RESULTS

Current users of PPIs had an increased risk of hip/femur fracture yielding an adjusted odds ratio (AOR) of 1.20 (95% CI 1.04-1.40). Fracture risk attenuated with increasing durations of use, resulting in AORs of 1.26 (95% CI 0.94-1.68) in the first 3 months, 1.31 (95% CI 0.97-1.75) between 3 and 12 months, 1.18 (95% CI 0.92-1.52) between 13 and 36 months and 1.09 (95% CI 0.81-1.47) for use longer than 36 months.

CONCLUSION

Our findings show that there is probably no causal relationship between PPI use and hip fracture risk. The observed association may be the result of unmeasured distortions: although current use of PPIs was associated with a 1.2-fold increased risk of hip/femur fracture, the positive association was attenuated with longer durations of continuous use. Our findings do not support that discontinuation of PPIs decreases risk of hip fracture in elderly patients.

Effects of NSAIDs on Differentiation and Function of Human and Murine Osteoclasts - Crucial 'Human Osteoclastology'

Osteoclasts play a critical role in both normal bone metabolism and bone resorption in the joints of patients with rheumatoid arthritis. It has been reported that non-steroidal anti-inflammatory drugs (NSAIDs) inhibit murine osteoclastogenesis in vitro and murine arthritis models in vivo, but not the destruction of joints of patients with rheumatoid arthritis. In the current review article, we review the recent findings in the effect of NSAIDs on the formation and function of human and murine osteoclasts both in vitro and in vivo, underlining the importance of studies using human osteoclasts. Since 2009, we have suggested a novel term ‘human osteoclastology’.

A systematic review of the therapeutic interventions for heterotopic ossification after spinal cord injury

STUDY DESIGN

Systematic review.

OBJECTIVE

To conduct a systematic review of the effectiveness of interventions used to prevent and treat heterotopic ossification (HO) after spinal cord injury (SCI).

SETTING

St Joseph's Parkwood Hospital, London, Ontario, Canada.

METHODS

MEDLINE, CINAHL, EMBASE and PsycINFO databases were searched for articles addressing the treatment of HO after SCI. Studies were selected by two reviewers and were only included for analysis if at least 50% of the subjects had an SCI, there were at least three SCI subjects and if the study subjects participated in a treatment or intervention. Study quality was assessed by two independent reviewers using the Downs and Black evaluation tool for all studies, as well as the PEDro assessment scale for randomized control trials only. Levels of evidence were assigned using a modified Sackett scale.

RESULTS

A total of 13 studies met the inclusion criteria. The selected articles were divided into prevention or treatment of post-SCI HO. Nonsteroidal anti-inflammatory drugs (NSAIDs), warfarin, and pulse low-intensity electrogmagnetic field (PLIMF) therapy were reviewed as prophylactic measures. Bisphosphonates, radiotherapy and excision were reviewed as treatments of post-SCI HO.

CONCLUSIONS

Pharmacological treatments of HO after SCI had the highest level of research evidence supporting their use. Of these, NSAIDs showed greatest efficacy in the prevention of HO when administered early after an SCI, whereas bisphosphonates were the intervention with strongest supportive evidence once HO had developed. Of the non-pharmacological interventions, PLIMF was supported by the highest level of evidence; however, more research is needed to fully understand its role.

Prostaglandin expression profile in hypoxic osteoblastic cells

Conditions such as fracture and unloading have been shown to be associated with tissue and cellular hypoxia in bone. The effects of hypoxia on bone cell physiology and ultimately its impact on bone tissue repair and remodeling are not well understood. In this study, we investigated the role of hypoxia on prostaglandin release from osteoblastic cells cultured in 2% (hypoxia), 5% (potentially cellular normoxia), and 21% (normoxia for standard cell culture conditions) oxygen for up to 24 h. We quantified the effects of reduced oxygen tension on the release of prostaglandin (PG)E(2), PGF(2alpha), PGD(2), and PGI(2). The mechanism by which hypoxia increases PG production was investigated by examining the various regulatory components of the PG biosynthetic pathway. Our data show that PGE(2) levels alone are significantly elevated under hypoxic conditions. Also, we show that cyclooxygenase (COX)-1 and COX-2 play an important role in hypoxia-induced PGE(2) production, possibly via a mechanism involving changes in their respective activity levels under low oxygen conditions. The effect of hypoxia on PGE(2) levels was mimicked by dimethyloxaloglycine, a known activator of the HIF pathway. In addition, we confirmed that HIF-1alpha was stabilized in osteoblastic cells under hypoxia. Taken together these data suggest a role for the HIF pathway in regulation of PGE(2) levels under hypoxic conditions. Previous studies have detected release of prostaglandins from areas of damaged bone, such as a fracture site, and our data may contribute to an understanding of how this release is regulated.

Cell-free and cell-based approaches for bone regeneration

The clinical augmentation of bone currently involves the use of autogenous or allogeneic bone grafts and synthetic materials, all of which are associated with limitations. Research on the safe enhancement of bone formation concerns the potential value of scaffolds, stem cells, gene therapy, and chemical and mechanical signals. Optimal scaffolds are engineered to provide mechanical stability while supporting osteogenesis, osteoconduction and/or osteoinduction. Scaffold materials include natural or synthetic polymers, ceramics, and composites. The resorption, mechanical strength and efficacy of these materials can be manipulated through structural and chemical design parameters. Cell-seeded scaffolds contain stem cells or progenitor cells, such as culture-expanded marrow stromal cells and multipotent skeletal progenitor cells sourced from other tissues. Despite extensive evidence from proof-of-principle studies, bone tissue engineering has not translated to clinical practice. Much of the research involves in vitro and animal models that do not replicate potential clinical applications. Problem areas include cell sources and numbers, over-reliance on existing scaffold materials, optimum delivery of factors, control of transgene expression, vascularization, integration with host bone, and the capacity to form bone and marrow structures in vivo. Current thinking re-emphasizes the potential of biomimetic materials to stimulate, enhance, or control bone's innate regenerative capacity at the implantation site.

Diclofenac sodium inhibits NFkappaB transcription in osteoclasts

A non-steroidal anti-inflammatory drug, diclofenac, acts efficiently against inflammation; however, down-regulation of diclofenac on bone remodeling has raised concerns. The inhibitory mechanisms of diclofenac are poorly understood. We hypothesized that diclofenac down-regulates osteoclast differentiation and activation via inhibition of the translocation of phosphorylated nuclear factor kappa B (NFkappaB). When osteoclasts prepared from mouse hematopoietic stem cells were treated with diclofenac, tartrateresistant acid phosphatase-positive multinucleated cells decreased in a concentration-dependent manner. Pit formation assay revealed the abolition of osteoclastic bone resorption; levels of cathepsin K transcripts, an osteoclastic resorption marker, were down-regulated time-dependently. Diclofenac induced the accumulation of the inhibitor of kappa B in cytosol, which led to suppression of the nuclear translocation of NFkappaB and phosphorylated NFkappaB. These results suggest that the novel mechanism of diclofenac for bone remodeling is associated with phosphorylated NFkappaB reduction, which regulates osteoclast differentiation and activation.