NSAIDS inhibit in vitro MSC chondrogenesis but not osteogenesis: implications for mechanism of bone formation inhibition in man

The Effect of Nonsteroidal Anti-inflammatory Drugs on Union Rates Following Joint Arthrodesis: A Meta-Analysis

Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most widely used and prescribed medications because of their important role in reducing inflammation and pain, in addition to their non-addictive properties and safety profiles. However, some studies have documented an association between NSAIDs and delayed union or nonunion of joint arthrodesis procedures due to a potential inhibition of the bone's inflammatory healing response. As a result, some orthopedic surgeons hesitate to prescribe NSAIDs after an arthrodesis procedure. The purpose of this meta-analysis is to review all relevant literature regarding the effect of NSAIDs on union rates after arthrodesis and determine if NSAID therapy increases the risk of non-union in the setting of arthrodesis procedures. The study hypothesis was that NSAIDs would not have a significant effect on the risk of nonunion after arthrodesis. A thorough systematic review of Medline, Embase, the Cochrane Database of Systematic Reviews, and the Web of Science identified 3,050 articles to be screened. The variables of interest encompassed demographic factors, procedural details, type and administration of NSAIDs, the number of patients exposed to NSAIDs with and without successful union (case group), as well as the number of patients who did not receive NSAIDs with and without successful union (control group). All the data were analyzed using a maximum likelihood random-effects model. The number of non-union events versus routine healing from each study was used to calculate the odds ratio (OR) of successful healing after arthrodesis procedures with versus without NSAID therapy. Thirteen articles met the inclusion criteria for the meta-analysis. NSAID exposure showed an increased risk of nonunion, delayed union, or both following arthrodesis procedures; however, this did not meet statistical significance (OR, 1.48; confidence interval [CI], 0.96 to 2.30). A sub-analysis of pediatric and adult studies showed a significant increase in non-union risk in adults (OR, 1.717; CI, 1.012 to 2.914) when removing the pediatric cohort (p = 0.045). This meta-analysis provides evidence that NSAIDs can increase the risk of nonunion, delayed union, or both following arthrodesis procedures in adults. However, the study did not identify a risk of nonunion, delayed union, or both following arthrodesis procedures in the pediatric population.

Osteoimmunology: Interactions With the Immune System in Spinal Fusion

Spinal fusion is important for the clinical success of patients undergoing surgery, and the immune system plays an increasingly recognized role. Osteoimmunology is the study of the interactions between the immune system and bone. Inflammation impacts the osteogenic, osteoconductive, and osteoinductive properties of bone grafts and substitutes and ultimately influences the success of spinal fusion. Macrophages have emerged as important cells for coordinating the immune response following spinal fusion surgery, and macrophage-derived cytokines impact each phase of bone graft healing. This review explores the cellular and molecular immune processes that regulate bone homeostasis and healing during spinal fusion.

Two Amnion-Derived Mesenchymal Stem-Cells Injections to Osteoarthritic Elbows in Dogs-Pilot Study

The aim of the study was to investigate the potential of cell-based regenerative therapy for elbow joints affected by osteoarthritis. Interest was focused on two intra-articular applications of amnion-derived mesenchymal stem cells (A-MSCs) to a group of different breeds of dogs with elbow osteoarthritis (13 joints). Two injections were performed 14 days apart. We evaluated synovial fluid biomarkers, such as IFN-γ, IL-6, IL-15, IL-10, MCP-1, TNF-α, and GM-CSF, by multiplex fluorescent micro-bead immunoassay in the treated group of elbows (n = 13) (day 0, day 14, and day 28) and in the control group of elbows (n = 9). Kinematic gait analysis determined the joint range of motion (ROM) before and after each A-MSCs application. Kinematic gait analysis was performed on day 0, day 14, and day 28. Kinematic gait analysis pointed out improvement in the average range of motion of elbow joints from day 0 (38.45 ± 5.74°), day 14 (41.7 ± 6.04°), and day 28 (44.78 ± 4.69°) with statistical significance (p < 0.05) in nine elbows. Correlation analyses proved statistical significance (p < 0.05) in associations between ROM (day 0, day 14, and day 28) and IFN-γ, IL-6, IL-15, MCP-1, TNF-α, and GM-CSF concentrations (day 0, day 14, and day 28). IFN-γ, IL-6, IL-15, MCP-1, GM-CSF, and TNF- α showed negative correlation with ROM at day 0, day 14, and day 28, while IL-10 demonstrated positive correlation with ROM. As a consequence of A-MSC application to the elbow joint, we detected a statistically significant (p < 0.05) decrease in concentration levels between day 0 and day 28 for IFN-γ, IL-6, and TNF-α and statistically significant increase for IL-10. Statistical significance (p < 0.05) was detected in TNF-α, IFN-γ, and GM-CSF concentrations between day 14 and the control group as well as at day 28 and the control group. IL-6 concentrations showed statistical significance (p < 0.05) between day 14 and the control group.

The Role of COX-2 and PGE2 in the Regulation of Immunomodulation and Other Functions of Mesenchymal Stromal Cells

The ability of MSCs to modulate the inflammatory environment is well recognized, but understanding the molecular mechanisms responsible for these properties is still far from complete. Prostaglandin E2 (PGE2), a product of the cyclooxygenase 2 (COX-2) pathway, is indicated as one of the key mediators in the immunomodulatory effect of MSCs. Due to the pleiotropic effect of this molecule, determining its role in particular intercellular interactions and aspects of cell functioning is very difficult. In this article, the authors attempt to summarize the previous observations regarding the role of PGE2 and COX-2 in the immunomodulatory properties and other vital functions of MSCs. So far, the most consistent results relate to the inhibitory effect of MSC-derived PGE2 on the early maturation of dendritic cells, suppressive effect on the proliferation of activated lymphocytes, and stimulatory effect on the differentiation of macrophages into M2 phenotype. Additionally, COX-2/PGE2 plays an important role in maintaining the basic life functions of MSCs, such as the ability to proliferate, migrate and differentiate, and it also positively affects the formation of niches that are conducive to both hematopoiesis and carcinogenesis.

Cross-species comparisons reveal resistance of human skeletal stem cells to inhibition by non-steroidal anti-inflammatory drugs

Fracture healing is highly dependent on an early inflammatory response in which prostaglandin production by cyclo-oxygenases (COX) plays a crucial role. Current patient analgesia regimens favor opioids over Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) since the latter have been implicated in delayed fracture healing. While animal studies broadly support a deleterious role of NSAID treatment to bone-regenerative processes, data for human fracture healing remains contradictory. In this study, we prospectively isolated mouse and human skeletal stem cells (SSCs) from fractures and compared the effect of various NSAIDs on their function. We found that osteochondrogenic differentiation of COX2-expressing mouse SSCs was impaired by NSAID treatment. In contrast, human SSCs (hSSC) downregulated COX2 expression during differentiation and showed impaired osteogenic capacity if COX2 was lentivirally overexpressed. Accordingly, short- and long-term treatment of hSSCs with non-selective and selective COX2 inhibitors did not affect colony forming ability, chondrogenic, and osteogenic differentiation potential in vitro. When hSSCs were transplanted ectopically into NSG mice treated with Indomethacin, graft mineralization was unaltered compared to vehicle injected mice. Thus, our results might contribute to understanding species-specific differences in NSAID sensitivity during fracture healing and support emerging clinical data which conflicts with other earlier observations that NSAID administration for post-operative analgesia for treatment of bone fractures are unsafe for patients.

Influence of exposure to microbial ligands, immunosuppressive drugs and chronic kidney disease on endogenous immunomodulatory gene expression in feline adipose-derived mesenchymal stem cells

OBJECTIVES

Feline autologous mesenchymal stem cells (MSCs) show promise for immunomodulatory activity, but the functional impact of chronic kidney disease (CKD), concurrent immunosuppressive drug administration or infection is unknown. The study objectives compare endogenous cytokine gene expression (interleukin [IL]-6, IL-10, IL-12p40, IL-18 and transforming growth factor beta [TGF-β]) in adipose-derived MSCs (aMSCs) from cats with and without CKD, following in vitro exposure to microbial ligands and treatment with common immunosuppressive drugs.

METHODS

Previously obtained aMSCs, phenotype CD44+, CD90+, CD105+ and MHCII-, from cats with (n = 6) and without (n = 6) CKD were compared via real-time PCR (RT-PCR) for immunomodulatory gene expression. aMSCs were exposed in vitro to lipopolysaccharide (LPS), peptidoglycan or polyinosinic:polycytidylic acid (Poly I:C), simulating bacterial or viral exposure, respectively. aMSCs were also exposed to ciclosporin, dexamethasone or methotrexate. Gene expression was measured using RT-PCR, and Cq was utilized after each run to calculate the delta cycle threshold.

RESULTS

aMSCs isolated from healthy and CKD cats showed no significant differences in gene expression in the five measured cytokines. No significant changes in measured gene expression after drug treatment or microbial ligand stimulation were observed between normal or CKD affected cats. Proinflammatory genes (IL-6, IL-12p40 and IL-18) showed altered expression in aMSCs from both groups when compared with the same cells in standard culture after exposure to methotrexate. Poly I:C altered IL-6 and TGF-β gene expression in aMSCs from both healthy and CKD cats when compared with the same cells in standard culture.

CONCLUSIONS AND RELEVANCE

The five genes tested showed no statistical differences between aMSCs from healthy or CKD cats. There was altered cytokine gene expression between the control and treatment groups of both healthy and CKD cats suggesting feline aMSCs have altered function with immunosuppressive treatment or microbial ligand exposure. Although the current clinical relevance of this pilot study comparing brief exposure to select agents in vitro in aMSCs from a small number of cats is unknown, the study highlights a need for continued investigation into the effects of disease and concurrent therapies on use of cell-based therapies in feline patients.

NSAIDs Reduce Therapeutic Efficacy of Mesenchymal Stromal Cell Therapy in a Rodent Model of Posttraumatic Osteoarthritis

BACKGROUND

Intra-articular injections of human mesenchymal stromal cells (hMSCs) have shown promise in slowing cartilage degradation in posttraumatic osteoarthritis (PTOA). Clinical use of cell therapies for osteoarthritis has accelerated in recent years without sufficient scientific evidence defining best-use practices. Common recommendations advise patients to avoid nonsteroidal anti-inflammatory drug (NSAID) use before and after cell injection over concerns that NSAIDs may affect therapeutic efficacy. Recommendations to restrict NSAID use are challenging for patients, and it is unclear if patients are compliant.

HYPOTHESIS

NSAIDs will reduce the efficacy of hMSC therapy in treating a preclinical model of PTOA.

STUDY DESIGN

Controlled laboratory study.

METHODS

Lewis rats underwent medial meniscal transection (MMT) surgery to induce PTOA or a sham (sham group) surgery that did not progress to PTOA. Rats received naproxen solution orally daily before (Pre-NSAID group) or after (Post-NSAID group) hMSC treatment, throughout the course of the experiment (Full-NSAID group), or received hMSCs without NSAIDs (No NSAID). Cartilage morphology and composition were quantified using contrast-enhanced micro-computed tomography and histology. Pain (secondary allodynia) was measured using a von Frey filament.

RESULTS

Injection of hMSCs attenuated cartilage degeneration associated with MMT. hMSCs prevented proteoglycan loss, maintained smooth cartilage surfaces, reduced cartilage lesions, reduced mineralized osteophyte formation, and reduced pain by week 7. The Pre-NSAID group had decreased proteoglycan levels compared with the hMSC group, although there were no other significant differences. Thus, pretreatment with NSAIDs had minimal effects on the therapeutic benefits of hMSC injections. The Post-NSAID and Full-NSAID groups, however, exhibited significantly worse osteoarthritis than the hMSC-only group, with greater proteoglycan loss, surface roughness, osteophyte volume, and pain.

CONCLUSION

Use of NSAIDs before hMSC injection minimally reduced the therapeutic benefits for PTOA, which included preservation of cartilage surface integrity as well as a reduction in osteophytes. Use of NSAIDs after injections, however, substantially reduced the therapeutic efficacy of cellular treatment.

CLINICAL RELEVANCE

Our data support the clinical recommendation of avoiding NSAID use after hMSC injection but suggest that using NSAIDs before treatment may not substantially diminish the therapeutic efficacy of cell treatment.

A dual functional chondro-inductive chitosan thermogel with high shear modulus and sustained drug release for cartilage tissue engineering

We report a chitosan-based nanocomposite thermogel with superior shear modulus resembling that of cartilage and dual pro-chondrogenic and anti-inflammatory functions. Two therapeutic agents, kartogenin (KGN) and diclofenac sodium (DS), are employed to promote chondrogenesis of stem cells and suppress inflammation, respectively. To extend the release time in a controlled manner, KGN is encapsulated in the uniform-sized starch microspheres and DS is loaded into the halloysite nanotubes. Both drug carriers are doped into the maleimide-modified chitosan hydrogel to produce a shear modulus of 167 ± 5 kPa that is comparable to that of articular cartilage (50-250 kPa). Owing to the hydrogel injectability and relatively suitable gelation time (5 ± 0.5 min) at 37 °C, this system potentially constitutes a manageable platform for clinical practice. Moreover, sustained linear drug release for over a month boosts chondro-differentiation of stem cells to eliminate the necessity for multiple administrations. Considering virtues such as thermogel strength and ability to co-deliver anti-inflammatory and chondro-inductive biomolecules continuously, the materials and strategy have promising potential in functional cartilage tissue engineering.

Ibuprofen in Therapeutic Concentrations Affects the Secretion of Human Bone Marrow Mesenchymal Stromal Cells, but Not Their Proliferative and Migratory Capacity

Mesenchymal stromal cells (MSCs) are able to modulate the immune system activity and the regeneration processes mainly through the secretion of multiple soluble factors, including prostaglandin E2 (PGE₂). PGE₂ is produced as a result of cyclooxygenases (COX) activity. In the present study, we investigated how ibuprofen, a nonselective COX inhibitor, affects the proliferation, migration and secretion of human bone marrow MSCs (hBM-MSCs). For this purpose, six hBM-MSCs populations were treated with ibuprofen at doses which do not differ from maximum serum concentrations during standard pharmacotherapy. Ibuprofen treatment (25 or 50 µg/mL) substantially reduced the secretion of PGE₂ in all tested populations. Following ibuprofen administration, MSCs were subjected to proliferation (BrdU), transwell migration, and scratch assays, while its effect on MSCs secretome was evaluated by Proteome Profiler and Luminex immunoassays. Ibuprofen did not cause statistically significant changes in the proliferation rate and migration ability of MSCs (p > 0.05). However, ibuprofen (25 µg/mL for 3 days) significantly decreased mean secretion of: CCL2 (by 44%), HGF (by 31%), IL-6 (by 22%), VEGF (by 20%) and IL-4 (by 8%) compared to secretion of control MSCs (p < 0.05). Our results indicate that ibuprofen at therapeutic concentrations may impair the pro-regenerative properties of hBM-MSCs.

Do Nonsteroidal Anti-Inflammatory Drugs Have a Deleterious Effect on Cartilage Repair? A Systematic Review

OBJECTIVES

The purpose of this study was to systematically review the available evidence regarding any plausible deleterious effects of nonsteroidal anti-inflammatory drugs (NSAIDs) on chondrocytes, chondrocyte differentiation, and allograft or autograft incorporation after cartilage repair procedures.

DESIGN

Three databases (PubMed, Science Direct, and Cochrane Library) were screened for eligible studies: investigating the effects of NSAIDs on chondrocytes, chondrogenic differentiation, or allograft/autograft incorporation. This evaluation included studies of any level of evidence, written in English, reporting clinical or preclinical results, published in peer review journals and dealing with our topic. All articles evaluating the effects of NSAIDs on either osteoarthritic (OA) chondrocyte samples or OA chondrocyte models were excluded. Moreover, articles about bone healing in which allograft or autograft incorporation was not investigated were also excluded. Methodologic quality assessment was performed for in vivo animal studies according to ARRIVE guidelines, and risk of bias of each included study was identified using the ROBINS-I tool.

RESULTS

Eighteen studies were included in the review: 4 in vitro studies, 13 animal studies, and 1 human study. According to these studies NSAIDs have no detrimental effect on healthy mature chondrocytes; however, these drugs influence chondrocyte differentiation and graft incorporation and therefore may interfere with chondrogenesis and incorporation after transplantation of chondrocytes or osteochondral grafts.

CONCLUSION

The use of NSAIDs, systemic or local, after cartilage repair procedures should be avoided unless a substantial clinical benefit would otherwise be withheld from the patient. More human studies are needed to analyze the effect of NSAIDs on cartilage repair.

Burn-induced heterotopic ossification from incidence to therapy: key signaling pathways underlying ectopic bone formation

Burn injury is one of the potential causes of heterotopic ossification (HO), which is a rare but debilitating condition. The incidence ranges from 3.5 to 5.6 depending on body area. Burns that cover a larger percentage of the total body surface area (TBSA), require skin graft surgeries, or necessitate pulmonary intensive care are well-researched risk factors for HO. Since burns initiate such complex pathophysiological processes with a variety of molecular signal changes, it is essential to focus on HO in the specific context of burn injury to define best practices for its treatment. There are numerous key players in the pathways of burn-induced HO, including neutrophils, monocytes, transforming growth factor-β1-expressing macrophages and the adaptive immune system. The increased inflammation associated with burn injuries is also associated with pathway activation. Neurological and calcium-related contributions are also known. Endothelial-to-mesenchymal transition (EMT) and vascularization are known to play key roles in burn-induced HO, with hypoxia-inducible factor-1 (HIF-1) and vascular endothelial growth factor (VEGF) as potential initiators. Currently, non-steroidal anti-inflammatory drugs (NSAIDs) and radiotherapy are effective prophylaxes for HO. Limited joint motion, ankylosis and intolerable pain caused by burn-induced HO can be effectively tackled via surgery. Effective biomarkers for monitoring burn-induced HO occurrence and bio-prophylactic and bio-therapeutic strategies should be actively developed in the future.

Modulation of T-Cell Activation Markers Expression by the Adipose Tissue-Derived Mesenchymal Stem Cells of Patients with Rheumatic Diseases

Background:

Activated T lymphocytes play an important role in the pathogenesis of rheumatic diseases (RD). Mesenchymal stem cells (MSCs) possess immunoregulatory activities but such functions of MSCs from bone marrow of systemic lupus erythematosus (SLE), systemic sclerosis (SSc), and ankylosing spondylitis (AS) patients are impaired. Adipose tissue–derived MSCs (ASCs) are an optional pool of therapeutically useful MSCs, but biology of these cells in RD is poorly known. This study aimed at investigating the effect of ASCs from RD patients and healthy donors (HD) on the expression of the key T-cell activation markers.

Methods:

ASCs were isolated from subcutaneous abdominal fat from SLE (n = 16), SSc (n = 18), and AS (n = 16) patients, while five human ASCs lines from HD were used as a control. Untreated and cytokine (tumor necrosis factor α + interferon γ)-treated ASCs were co-cultured with allogenic, mitogen (phytohemagglutinin)-stimulated peripheral blood mononuclear cells (PBMCs) or purified anti-CD3/CD28-activated CD4⁺ T lymphocytes. Contacting and noncontacting ASCs-PBMCs co-cultures were performed. RD/ASCs were analyzed in co-cultures with both allogeneic and autologous PBMCs. Flow cytometry analysis was used to evaluate expression of CD25, HLA-DR, and CD69 molecules on CD4⁺ and CD8⁺ cells.

Results:

In co-cultures with allogeneic, activated CD4⁺ T cells and PBMCs, HD/ASCs and RD/ASCs downregulated CD25 and HLA-DR, while upregulated CD69 molecules expression on both CD4⁺ and CD8⁺ cells with comparable potency. This modulatory effect was similar in contacting and noncontacting co-cultures. RD/ASCs exerted weaker inhibitory effect on CD25 expression on autologous than allogeneic CD4⁺ and CD8⁺ T cells.

Conclusion:

RD/ASCs retain normal capability to regulate expression of activation markers on allogeneic T cells. Both HD/ASCs and RD/ASCs exert this effect independently of their activation status, mostly through the indirect pathway and soluble factors. However, autologous CD4⁺ and CD8⁺ T cells are partially resistant to RD/ASCs inhibition of CD25 expression, suggesting weaker control of T-cell activation in vivo.

An Innovative Pain Control Method Using Peripheral Nerve Block and Patient-Controlled Analgesia With Ketorolac After Bone Surgery in the Ankle Area: A Prospective Study

Although postoperative pain is inevitable after bone surgery, there is no general consensus regarding its ideal management. We hypothesized that the combination of ultrasound-guided peripheral nerve block (PNB) and patient-controlled analgesia (PCA) with ketorolac would be useful for pain control and reducing opioid usage. This prospective study aimed to evaluate the effectiveness of this method. This study included 95 patients aged >18 years who underwent bone surgery in the ankle area from June to December 2018. All operations were performed under anesthetic PNB, and additional PNB was given for pain control ∼11 hours after preoperative PNB. An additional PCA with ketorolac, started before rebound pain was experienced, was used for pain control in group A (49 patients) but not group B (46 patients). We used intramuscular injection with pethidine or ketorolac as rescue analgesics if pain persisted. A visual analogue scale (VAS) for pain was used to quantify pain at 6, 12, 18, 24, 36, 48, and 72 hours postoperatively. Patient satisfaction was assessed, along with side effects in both groups. VAS pain scores differed significantly between the groups at 24 hours after the operation (p = .013). All patients in group A were satisfied with the pain control method; however, 5 patients in group B were dissatisfied (p = .001), 3 owing to severe postoperative pain and 2 owing to postoperative nausea and vomiting. An average of 0.75 and 11.40 mg pethidine per patient was used in groups A and B, respectively, for 3 days. We concluded that the combined use of ultrasound-guided PNB and PCA with ketorolac can be an effective postoperative method of pain control that can reduce opioid usage.

NSAIDs inhibit bone healing through the downregulation of TGF-β3 expression during endochondral ossification

INTRODUCTION & AIMS

Non Steroidal Anti-Inflammatory drugs (NSAIDs) are potent inhibitors of post-traumatic pain. Several studies have highlighted that NSAIDs could exert a negative effect on bone healing process possibly by down-regulating chondrogenesis and endochondral ossification. The aim of the study is to explore the potential mechanism though which NSAIDs can affect chondrogenesis. M&M: Trabecular bone from the fracture site was isolated from 10 patients suffering from long bone fractures. Mesenchymal Stem Cells (MSCs) were isolated following collagenase digestion and functional assays to assess the effect of diclofenac sodium on chondrogenesis were performed. Gene expression analysis of 84 key molecules was performed.

RESULTS

Diclofenac sodium inhibits chondrogenic differentiation and induces a strong inhibition of prostaglandin E-2 (PGE-2) production during chondrogenic differentiation. Replenishment of PGE-2 did not reverse this negative effect. Chondrogenic inhibition is similar in cells treated only for the first week of chondrogenic differentiation or continuously for 3 weeks. Gene analysis shows a strong downregulation of TGF-β3 and FGF-1 while TNF was upregulated.

CONCLUSION

NSAIDs seem to affect the transition phase of mesenchymal stem cells towards functional chondrocytes. This effect is unrelated to the endogenous production of PGE-2. The downregulation of the expression of key molecules like TGF-β3 seem to be the underlying mechanism.

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.

Evaluation of the Impact of Different Pain Medication and Proton Pump Inhibitors on the Osteogenic Differentiation Potential of hMSCs Using 99mTc-HDP Labelling

First-line analgetic medication used in the field of musculoskeletal degenerative diseases, like Nonsteroidal anti-inflammatory drugs (NSAIDs), reduces pain and prostaglandin synthesis, whereby peptic ulcers are a severe adverse effect. Therefore, proton pump inhibitors (PPI) are frequently used as a concomitant medication to reduce this risk. However, the impact of NSAIDs or metamizole, in combination with PPIs, on bone metabolism is still unclear. Therefore, human mesenchymal stem cells (hMSCs) were cultured in monolayer cultures in 10 different groups for 21 days. New bone formation was induced as follows: Group 1 negative control group, group 2 osteogenic differentiation media (OSM), group 3 OSM with pantoprazole (PAN), group 4 OSM with ibuprofen (IBU), group 5 OSM with diclofenac (DIC), group 6 OSM with metamizole (MET), group 7 OSM with ibuprofen and pantoprazole (IBU + PAN), group 8 OSM with diclofenac and pantoprazole (DIC + PAN), group 9 OSM with metamizole and pantoprazole (MET + PAN) and group 10 OSM with diclofenac, metamizole and pantoprazole (DIC + MET + PAN). Hydroxyapatite content was evaluated using high-sensitive radioactive ^99mTc-HDP labeling. Within this study, no evidence was found that the common analgetic medication, using NSAIDs alone or in combination with pantoprazole and/or metamizole, has any negative impact on the osteogenic differentiation of mesenchymal stem cells in vitro. To the contrary, the statistical results indicate that pantoprazole alone (group 3 (PAN) (p = 0.016)) or diclofenac alone (group 5 (DIC) (p = 0.008)) enhances the deposition of minerals by hMSCS in vitro. There is an ongoing discussion between clinicians in the field of orthopaedics and traumatology as to whether post-surgical (pain) medication has a negative impact on bone healing. This is the first hMSC in vitro study that investigates the effects of pain medication in combination with PPIs on bone metabolism. Our in vitro data indicates that the assumed negative impact on bone metabolism is subsidiary. These findings substantiate the thesis that, in clinical medicine, the patient can receive every pain medication needed, whether or not in combination with PPIs, without any negative effects for the osteo-regenerative potential.

Cytotoxic and osteogenic effects of crocin and bicarbonate from calcium phosphates for potential chemopreventative and anti-inflammatory applications in vitro and in vivo

Delayed healing and nonhealing of bone defects or resected bone sites remains an important clinical concern in the biomedical field. Osteosarcoma is one of the most common types of primary bone cancers. Among calcium phosphates, hydroxyapatite (HA) and tricalcium phosphate (TCP) are the most widely used in various biomedical applications for bone reconstruction and replacement. In this study, crocin, saffron's natural bioactive and anti-inflammatory molecule, and bicarbonate, a neutralizing agent, were directly loaded onto HA disks to evaluate their in vitro release and effect on human osteoblast and osteosarcoma cell lines. This was assessed through release, initial toxicity, drug optimization, final toxicity studies and in vivo anti-inflammatory assessment through H&E indexing. It is hypothesized that the release of crocin, bicarbonate, and the dual release of both agents will decrease osteosarcoma cellular viability with no effect on osteoblast cells. A plateaued release of crocin and bicarbonate was achieved over seven weeks in physiological and acidic environments, where bicarbonate was shown to modulate the release of crocin. Through morphological characterization and MTT assay analysis, bicarbonate showed no toxicity to human fetal osteoblast (hFOB) cells and crocin significantly enhanced osteoblast proliferation. Through drug concentration optimization, all drug loaded samples decreased human osteosarcoma (MG-63) viability by 50% compared to control samples by Day 11, with clear changes in cell spreading and morphology. Moreover, 3D printed TCP scaffolds loaded with crocin and bicarbonate were tested in vivo in order to assess their preliminary effects on inflammation in a rat distal femur model at 4 days. Lower inflammatory cellular recruitment was achieved in the presence of crocin and bicarbonate, compared to the control. These results suggest a pro-apoptotic mechanism against osteosarcoma as well as anti-inflammatory properties of crocin and bicarbonate, elucidating a potential application for osteosarcoma regulation and wound healing for bone tissue regeneration applications.

Mesenchymal Stem/Progenitor Cells: The Prospect of Human Clinical Translation

Mesenchymal stem/progenitor cells (MSCs) are key players in regenerative medicine, relying principally on their differentiation/regeneration potential, immunomodulatory properties, paracrine effects, and potent homing ability with minimal if any ethical concerns. Even though multiple preclinical and clinical studies have demonstrated remarkable properties for MSCs, the clinical applicability of MSC-based therapies is still questionable. Several challenges exist that critically hinder a successful clinical translation of MSC-based therapies, including but not limited to heterogeneity of their populations, variability in their quality and quantity, donor-related factors, discrepancies in protocols for isolation, in vitro expansion and premodification, and variability in methods of cell delivery, dosing, and cell homing. Alterations of MSC viability, proliferation, properties, and/or function are also affected by various drugs and chemicals. Moreover, significant safety concerns exist due to possible teratogenic/neoplastic potential and transmission of infectious diseases. Through the current review, we aim to highlight the major challenges facing MSCs' human clinical translation and shed light on the undergoing strategies to overcome them.

Long Noncoding RNAs as Bone Marrow Stem Cell Regulators in Osteoporosis

Long noncoding RNAs (lncRNAs) contribute toward regulating gene expression and cell differentiation and may be involved in the pathogenesis of several diseases. The objective of this study was to determine the expression patterns of lncRNAs in bone marrow mesenchymal stem cells (BMSCs) derived from patients with osteoporotic fractures and their relevance to osteogenic function. The BMSCs were isolated from the femoral head of patients with hip fractures (FRX) and controls with osteoarthritis (OA). We found 74 differentially expressed genes between FRX and OA, of which 33 were of the lncRNA type. Among them, 52 genes (20 lncRNAs) were replicated in another independent dataset. The differentially expressed lncRNAs were over-represented among those correlated with differentially expressed protein-coding genes. In addition, the comparison of pre- and post-differentiated paired samples revealed 163 differentially expressed genes, of which 99 were of the lncRNA type. Among them, the overexpression of LINC00341 induced an upregulation of typical osteoblastic genes. In conclusion, the analysis of lncRNA expression in BMSCs shows specific patterns in patients with osteoporotic fractures, as well as changes associated with osteogenic differentiation. The regulation of bone genes through lncRNAs might bring new opportunities for designing bone anabolic therapies in systemic and localized bone disorders.

Inflammatory Profile and Osteogenic Potential of Fracture Haematoma in Humans

Fracture haematoma forms immediately after fracture and is considered essential for the bone healing process. Its molecular composition has been briefly investigated with our current understanding being based on animal studies. This study aims to analyse the inflammatory cytokine content of fracture haematoma in humans and determine its effect on osteoprogenitor cells. Twenty-three patients were recruited following informed consent. Peripheral blood, fracture haematoma and bone were collected. A Luminex assay on the levels of 34 cytokines was performed and autologous peripheral blood samples served as control. Mesenchymal Stem Cells (MSCs) were isolated following collagenase digestion and functional assays were performed. Gene expression analysis of 84 key osteogenic molecules was performed. Thirty-three inflammatory cytokines were found to be significantly raised in fracture haematoma when compared to peripheral serum (p < 0.05). Amongst the most raised molecules were IL-8, IL-11 and MMP1, -2 and -3. Fracture haematoma did not significantly affect MSC proliferation, but ALP activity and calcium deposition were significantly increased in the MSCs undergoing osteogenic differentiation. Medium supplementations with fracture haematoma resulted in a statistically significant upregulation of osteogenic genes including the EGF, FGF2 and VEGFA. This seems to be the pathway involved in the osteogenic effect of fracture haematoma on bone cells. In conclusion, fracture haematoma is found to be a medium rich in inflammatory and immunomodulatory mediators. At the same time, it contains high levels of anti-inflammatory molecules, regulates osteoclastogenesis, induces angiogenesis and the production of the extracellular matrix. It appears that fracture haematoma does not affect osteoprogenitor cells proliferation as previously thought, but induces an osteogenic phenotype.

Increased Cellular Presence After Sciatic Neurectomy Improves the Bone Mechano-adaptive Response in Aged Mice

The mechano-adaptive response of bone to loading in the murine uniaxial tibial loading model is impaired in aged animals. Previous studies have shown that in aged mice, the amount of bone formed in response to loading is augmented when loads are applied following sciatic neurectomy. The synergistic effect of neurectomy and loading remains to be elucidated. We hypothesize that sciatic neurectomy increases cellular presence, thereby augmenting the response to load in aged mice. We examined bone adaptation in four groups of female C57BL/6J mice, 20-22 months old: (1) sham surgery + 9N loading; (2) sciatic neurectomy, sacrificed after 5 days; (3) sciatic neurectomy, sacrificed after 19 days; (4) sciatic neurectomy + 9N loading. We examined changes in bone cross sectional properties with micro-CT images, and static and dynamic histomorphometry with histological sections taken at the midpoint between tibiofibular junctions. The response to loading at 9N was not detectable with quantitative micro-CT data, but surface-specific histomorphometry captured an increase in bone formation in specific regions. 5 days following sciatic neurectomy, the amount of bone in the neurectomized leg was the same as the contralateral leg, but 19 days following sciatic neurectomy, there was significant bone loss in the neurectomized leg, and both osteoclasts and osteoblasts were recruited to the endosteal surfaces. When sciatic neurectomy and loading at 9N were combined, 3 out of 4 bone quadrants had increased bone formation, on the endosteal and periosteal surfaces (increased osteoid surface and mineralizing surface respectively). These data demonstrate that sciatic neurectomy increases cellular presence on the endosteal surface. With long-term sciatic-neurectomy, both osteoclasts and osteoblasts were recruited to the endosteal surface, which resulted in increased bone formation when combined with a sufficient mechanical stimulus. Controlled and localized recruitment of both osteoblasts and osteoclasts combined with appropriate mechanical loading could inform therapies for mechanically-directed bone formation.

Targeting anti-chondrogenic factors for the stimulation of chondrogenesis: A new paradigm in cartilage repair

Trauma and age-related cartilage disorders represent a major global cause of morbidity, resulting in chronic pain and disability in patients. A lack of effective therapies, together with a rapidly aging population, creates an impressive clinical and economic burden on healthcare systems. In this scenario, experimental therapies based on transplantation or in situ stimulation of skeletal Mesenchymal Stem/progenitor Cells (MSCs) have raised great interest for cartilage repair. Nevertheless, the challenge of guiding MSC differentiation and preventing cartilage hypertrophy and calcification still needs to be overcome. While research has mostly focused on the stimulation of cartilage anabolism using growth factors, several issues remain unresolved prompting the field to search for novel solutions. Recently, inhibition of anti-chondrogenic regulators has emerged as an intriguing opportunity. Anti-chondrogenic regulators include extracellular proteins as well as intracellular transcription factors and microRNAs that act as potent inhibitors of pro-chondrogenic signals. Suppression of these inhibitors can enhance MSC chondrogenesis and production of cartilage matrix. We here review the current knowledge concerning different types of anti-chondrogenic regulators. We aim to highlight novel therapeutic targets for cartilage repair and discuss suitable tools for suppressing their anti-chondrogenic functions. Further effort is needed to unveil the therapeutic perspectives of this approach and pave the way for effective treatment of cartilage injuries in patients. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Disease-modifying effects of COX-2 selective inhibitors and non-selective NSAIDs in osteoarthritis: a systematic review

Osteoarthritis (OA) is a potentially disabling disease whose progression is dependent on several risk factors. OA management usually involves the use of non-steroidal anti-inflammatory drugs (NSAIDs) that are the primary pharmacological treatments of choice. However, NSAIDs have often been associated with unwanted side effects. Cyclooxygenase (COX)-2 specific inhibitors, such as celecoxib, have been successfully used as an alternative in the past for OA treatment and have demonstrated fewer side effects. While abundant data are available for the clinical efficacy of drugs used for OA treatment, little is known about the disease-modifying effects of these agents. A previous review published by Zweers et al. (2010) assessed the available literature between 1990 and 2010 on the disease-modifying effects of celecoxib. In the present review, we aimed to update the existing evidence and identify evolving concepts relating to the disease-modifying effects of not just celecoxib, but also other NSAIDs. We conducted a review of the literature published from 2010 to 2016 dealing with the effects, especially disease-modifying effects, of NSAIDs on cartilage, synovium, and bone in OA patients. Our results show that celecoxib was the most commonly used drug in papers that presented data on disease-modifying effects of NSAIDs. Further, these effects appeared to be mediated through the regulation of prostaglandins, cytokines, and direct changes to tissues. Additional studies should be carried out to assess the disease-modifying properties of NSAIDs in greater detail.

The effect of nonsteroidal anti-inflammatory drugs on bone healing in humans: A qualitative, systematic review

STUDY OBJECTIVE

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used in postoperative pain management. While an increasing number of in vitro and animal studies point toward an inhibitory effect of NSAIDs on bone healing process, the few existing retro- and prospective clinical studies present conflicting data.

DESIGN

The aim of this qualitative, systematic review was to investigate the impact of perioperative use of NSAIDs in humans on postoperative fracture/spinal fusion healing compared to other used analgesics measured as fracture nonunion with radiological control.

PATIENTS/INTERVENTIONS

We performed a systematic literature search of the last 38 years using PubMed Embase and the Cochrane Controlled Trials Register including retro- and prospective clinical, human trials assessing the effect of NSAIDs on postoperative fracture/spinal fusion healing when used for perioperative pain management with a radiological follow up to assess eventual nonunion. Due to different study designs, drugs, dosages/exposition times and different methods to assess fracture nonunion, these studies were not pooled for a meta-analysis. A descriptive summary of all studies, level of evidence, study quality and study bias assessment using different scores were used.

MAIN RESULTS

Three prospective randomized controlled studies and thirteen retrospective cohort human studies were identified for a total of 12'895 patients. The overall study quality was low according to Jadad and Oxford Levels of Evidence scores.

CONCLUSIONS

Published results of human trials did not show strong evidence that NDAIDs for pain therapy after fracture osteosynthesis or spinal fusion lead to an increased nonunion rate. Reviewed studies present such conflicting data, that no clinical recommendation can be made regarding the appropriate use of NSAIDs in this context. Considering laboratory data of animal, human tissue research and recommendation of clinical reviews, a short perioperative exposition to NSAIDs is most likely not deleterious. However, randomized, controlled studies are warranted to support or refute this hypothesis.

Effect of COX-2 inhibition on tendon-to-bone healing and PGE2 concentration after anterior cruciate ligament reconstruction

BACKGROUND

Non-steroidal anti-inflammatory drugs are commonly used to reduce pain and inflammation in orthopaedic patients. Selective cyclooxygenase-2 (COX-2) inhibitors have been developed to minimize drug-specific side effects. However, they are suspected to impair both bone and tendon healing. The objective of this study is to evaluate the effect of COX-2 inhibitor administration on tendon-to-bone healing and prostaglandin E (PGE2) concentration.

METHODS

Thirty-two New Zealand white rabbits underwent reconstructions of the anterior cruciate ligaments and were randomized into four groups: Two groups postoperatively received a selective COX-2 inhibitor (Celecoxib) on a daily basis for 3 weeks, the two other groups received no postoperative COX-2 inhibitors at all and were examined after three or 6 weeks. The PGE2 concentration of the synovial fluid, the osseous integration of the tendon graft at tunnel aperture and midtunnel section, as well as the stability of the tendon graft were examined via biomechanic testing.

RESULTS

After 3 weeks, the PGE2 content of the synovial fluid in the COX-2 inhibitor recipients was significantly lower than that of the control group (p = 0.018). At the same time, the COX-2 inhibitor recipients had a significantly lower bone density and lower amount of new bone formation than the control group (p = 0.020; p = 0.028) in the tunnel aperture. At the 6-week examination, there was a significant increase in the PGE2 content within synovial fluid of the COX-2 inhibitor recipients (p = 0.022), whose treatment with COX-2 inhibitors had ended 3 weeks earlier; in contrast, the transplant stability decreased and was reduced by 37% compared to the controls.

CONCLUSIONS

Selective COX-2 inhibitors cause impaired tendon-to-bone healing, weaken mechanical stability and decrease PGE2 content of the synovial fluid. The present study suggests a reluctant use of COX-2 inhibitors when tendon-to-bone healing is intended.

Modulating the oxidative environment during mesenchymal stem cells chondrogenesis with serum increases collagen accumulation in agarose culture

Chondrogenesis of mesenchymal stem cells (MSCs) is induced in culture conditions that have been associated with oxidative stress, although the extent to which the oxidative environment affects differentiation and extracellular matrix (ECM) accumulation is not known. The objectives of this study were to evaluate the oxidative environment during MSCs chondrogenesis in conventional serum-free medium, and the effect of serum-supplementation on intracellular reactive oxygen species (ROS) and chondrogenesis. Young adult equine MSCs were seeded into agarose and cultured in chondrogenic medium, with or without 5% fetal bovine serum (FBS), for up to 15 days. Samples were evaluated for intracellular ROS, the antioxidant glutathione, ECM and gene expression measures of chondrogenesis, and carbonylation as an indicator of oxidative damage. Intracellular ROS increased with time in culture, and was lower in medium supplemented with FBS. Glutathione decreased ∼12-fold during early chondrogenesis (p < 0.0001), and was not affected by FBS (p = 0.25). After 15 days of culture, FBS supplementation increased hydroxyproline accumulation ∼80% (p = 0.0002); otherwise, measures of chondrogenesis were largely unaffected. Protein carbonylation in chondrogenic MSCs cultures was not significantly different between serum-free and FBS cultures (p = 0.72). Supplementation with adult equine serum increased hydroxyproline accumulation by 45% over serum-free culture (p = 0.0006). In conclusion, this study characterized changes in the oxidative environment during MSC chondrogenesis, and suggested that lowering ROS may be an effective approach to increase collagen accumulation. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:506-514, 2018.

Modulation of cartilage's response to injury: Can chondrocyte apoptosis be reversed?

Osteoarthritis is characterized by a chronic, progressive and irreversible degradation of the articular cartilage associated with joint inflammation and a reparative bone response. More than 100 million people are affected by this condition worldwide with significant health and welfare costs. Our available treatment options in osteoarthritis are extremely limited. Chondral or osteochondral grafts have shown some promising results but joint replacement surgery is by far the most common therapeutic approach. The difficulty lies on the limited regeneration capacity of the articular cartilage, poor blood supply and the paucity of resident progenitor stem cells. In addition, our poor understanding of the molecular signalling pathways involved in the senescence and apoptosis of chondrocytes is a major factor restricting further progress in the area. This review focuses on molecules and approaches that can be implemented to delay or even rescue chondrocyte apoptosis. Ways of modulating the physiologic response to trauma preventing chondrocyte death are proposed. The use of several cytokines, growth factors and advances made in altering several of the degenerative genetic pathways involved in chondrocyte apoptosis and degradation are also presented. The suggested approaches can help clinicians to improve cartilage tissue regeneration.

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.

Ketorolac Administered in the Recovery Room for Acute Pain Management Does Not Affect Healing Rates of Femoral and Tibial Fractures

OBJECTIVES

To determine whether ketorolac administered in the immediate perioperative period affects the rate of nonunion in femoral and tibial shaft fractures.

DESIGN

Retrospective comparative study.

SETTING

Single Institution, Academic Level 1 Trauma Center.

PATIENTS

Three hundred and thirteen skeletally mature patients with 137 femoral shaft (OTA 32) and 191 tibial shaft (OTA 42) fractures treated with intramedullary rod fixation.

INTERVENTION

Eighty patients with 33 femoral shaft and 52 tibial shaft fractures were administered ketorolac within the first 24 hours after surgery (group 1-study group). Two-hundred thirty-three patients with 104 femoral shaft and 139 tibial shaft fractures were not (group 2-control group).

MAIN OUTCOME MEASUREMENTS

Rate of reoperation for repair of a nonunion and time to union.

RESULTS

Average time to union of the femur was 147 days for group 1 and 159 days for group 2 (P = 0.57). Average time to union of the tibia was 175 days for group 1 and 175 days for group 2 (P = 0.57). There were 3 femoral nonunions (9%) in group 1 and eleven femoral nonunions (11.6%) in group 2 (P = 1.00). There were 3 tibial nonunions (5.8%) in group 1 and 17 tibial nonunions (12.2%) in group 2 (P = 0.29). The average dose of ketorolac for patients who healed their fracture was 85 mg, whereas it was 50 mg for those who did not (P = 0.27). All patients with a nonunion in the study group were current smokers.

CONCLUSIONS

Ketorolac administered in the first 24 hours after fracture repair for acute pain management does not seem to have a negative impact on time to healing or incidence of nonunion for femoral or tibial shaft fractures.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Effects of NSAIDs on the osteogenic differentiation of human adipose tissue-derived stromal cells

OBJECTIVES

Non-steroidal anti-inflammatory drugs (NSAIDs), used in the treatment of musculoskeletal pathologies, have been associated with impaired bone healing, possibly through inhibition of osteogenic differentiation. The adipose tissue (AT) is regarded as an attractive source of stromal cells for autologous cell transplantation in the bone. The effects of NSAIDs on human AT-derived stromal cells (hADSCs) are unknown.

METHODS

We examined the effect of several NSAIDs including meloxicam, parecoxib, lornoxicam, diclofenac and paracetamol on the proliferation of hADSCs by means of the PrestoBlue^® viability assay, and the osteogenic differentiation capacity of hADSCs by means of the alkaline phosphatase (ALP) activity, calcium deposition by alizarin red staining and osteogenic gene expression by semi-quantitative PCR.

KEY FINDINGS

Most of the drugs enhanced hADSC cell growth, while either positively affecting or not influencing alkaline phosphatase (ALP) activity, calcium deposition and osteogenic gene expression. Moreover, selective COX-2 inhibitor NSAIDs, such as meloxicam or parecoxib, were advantageous over the non-selective COX-1 and COX-2 inhibitor NSAIDs lornoxicam and diclofenac.

CONCLUSIONS

Altogether through this study, we show that NSAIDs, possibly depending on their selectivity for COX inhibition, leave the osteogenic differentiation capacity of hADSCs unaltered or might even enhance it.

The low molecular weight fraction of human serum albumin upregulates COX2, prostaglandin E2, and prostaglandin D2 under inflammatory conditions in osteoarthritic knee synovial fibroblasts

Background

The ability to decrease inflammation and promote healing is important in the intervention and management of a variety of disease states, including osteoarthritis of the knee (OAK). Even though cyclooxygenase 2 (COX2) has an established pro-inflammatory role, evidence suggests it is also critical to the resolution that occurs after the initial activation phase of the immune response. In this study, we investigated the effects of the low molecular weight fraction of 5% human serum albumin (LMWF-5A), an agent that has proven to decrease pain and improve function in OAK patients after intra-articular injection, on the expression of COX2 and its downstream products, prostaglandins (PGs).

Methods

Fibroblast-like synoviocytes from the synovial membrane of OAK patients were treated with LMWF-5A or saline as a control with or without the addition of interleukin-1β (IL-1β) or tumor necrosis factor α (TNFα) to elicit an inflammatory response. Cells were harvested for RNA and protein at 2, 4, 8, 12, and 24 h, and media was collected at 24 h for analysis of secreted products. COX2 mRNA expression was determined by qPCR, and COX2 protein expression was determined by western blot analysis. Levels of prostaglandin E2 (PGE2) and prostaglandin D2 (PGD2) in the media were quantified by competitive ELISA.

Results

In the presence of either IL-1β or TNFα, LMWF-5A increased the expression of both COX2 mRNA and protein, and this increase was significant compared to that observed with IL-1β- or TNFα-stimulated, saline-treated cells. Downstream of COX2, the levels of PGE2 were increased only in TNFα-stimulated, LMWF-5A-treated cells; however, in both IL-1β- and TNFα-stimulated cells, LMWF-5A increased the release of the anti-inflammatory prostaglandin PGD2.

Conclusion

LMWF-5A appears to trigger increased anti-inflammatory PG signaling, and this may be a primary component of its therapeutic mode of action in the treatment of OAK.

•

Proposed mechanism of action for biologic drug to treat osteoarthritis of the knee.

•

LMWF-5A affects the COX2 pathway in primary synoviocytes from osteoarthritic knees.

•

LMWF-5A may promote resolution of inflammation, healing, and cartilage regeneration.

Effects of Dexamethasone Concentration and Timing of Exposure on Chondrogenesis of Equine Bone Marrow-Derived Mesenchymal Stem Cells

OBJECTIVE

Dexamethasone is known to support mesenchymal stem cell (MSC) chondrogenesis, although the effects of dose and timing of exposure are not well understood. The objective of this study was to investigate these variables using a laboratory model of MSC chondrogenesis.

DESIGN

Equine MSCs were encapsulated in agarose and cultured in chondrogenic medium with 1 or 100 nM dexamethasone, or without dexamethasone, for 15 days. Samples were analyzed for extracellular matrix (ECM) accumulation, prostaglandin E2 and alkaline phosphatase secretion, and gene expression of selected collagens and catabolic enzymes. Timing of exposure was evaluated by ECM accumulation after dexamethasone was withdrawn over the first 6 days, or withheld for up to 3 or 6 days of culture.

RESULTS

ECM accumulation was not significantly different between 1 and 100 nM dexamethasone, but was suppressed ~40% in dexamethasone-free cultures. Prostaglandin E2 secretion, and expression of catabolic enzymes, including matrix metalloproteinase 13, and type X collagen was generally lowest in 100 nM dexamethasone and not significantly different between 1 nM and dexamethasone-free cultures. Dexamethasone could be withheld for at least 2 days without affecting ECM accumulation, while withdrawal studies suggested that dexamethasone supports ECM accumulation beyond day 6.

CONCLUSION

One nanomolar dexamethasone supported robust cartilage-like ECM accumulation despite not having an effect on markers of inflammation, although higher concentrations of dexamethasone may be necessary to suppress undesirable hypertrophic differentiation. While early exposure to dexamethasone was not critical, sustained exposure of at least a week appears to be necessary to maximize ECM accumulation.

Inflammation, Bone Healing, and Anti-Inflammatory Drugs: An Update

Fracture healing is a unique multifaceted process requiring the presence of cells, molecular mediators, and angiogenic factors. The state of inflammation dominates the initial phase, but the ideal magnitude and duration of the process for an optimal outcome remains obscure. Biological response modifiers, such as platelet-rich plasma (PRP) preparations, have been used to reconstitute the desirable early inflammatory state, but the results obtained remain inconclusive. Ongoing research to characterize and quantify the inflammatory response after bone fracture is essential in order to better understand the molecular insights of this localized reaction and to expand our armamentarium in the management of patients with an impaired fracture healing response. Non-steroidal anti-inflammatory drugs frequently administered for analgesia after trauma procedures continue to be a cause of concern for a successful bone repair response.

Effects of human umbilical cord mesenchymal stem cell transplantation combined with minimally invasive hematoma aspiration on intracerebral hemorrhage in rats

This study is to investigate the effects of human umbilical cord-mesenchymal stem cells (HUC-MSCs) transplantation combined with minimally invasive hematoma aspiration on neural functional recovery and p53 gene expression in rats with intracerebral hemorrhage (ICH). Collagenase type-IV was injected to the caudate nucleus of the rats to make ICH models. One hundred and twenty Sprague-Dawley rats with successful modeling were randomly divided into 4 groups, including the ICH group, hematoma aspiration group, HUC-MSCs transplantation group and HUC-MSCs transplantation combined with hematoma aspiration group (combination group). Neural functional status of the rats was assessed by modified neurological severity score (mNSS). Expression of p53 in the cerebral tissues surrounding ICH was detected by immunohistochemical assays. The scores of mNSS and the expression of p53 gene in the hematoma aspiration group, the HUC-MSCs transplantation group and the combination group were significantly lower than those in the ICH group at each indicated time point (p < 0.05). Intriguingly, mNSS scores and p53 expression in the combination group were significantly lower than those in the hematoma aspiration group on day 7, 14 and 30 (p < 0.05), and significantly lower than those in the HUC-MSCs transplantation group on day 14 and 30 (p < 0.05). HUC-MSCs transplantation combined with minimally invasive hematoma aspiration is more effective than either therapy alone in rats with ICH and could distinctly reduce the damage of nerve cells.

Mechanisms of peroxisome proliferator activated receptor γ regulation by non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) display anti-inflammatory, antipyretic and analgesic properties by inhibiting cyclooxygenases and blocking prostaglandin production. Previous studies, however, suggested that some NSAIDs also modulate peroxisome proliferator activated receptors (PPARs), raising the possibility that such off target effects contribute to the spectrum of clinically relevant NSAID actions. In this study, we set out to understand how peroxisome proliferator activated receptor-γ (PPARγ/PPARG) interacts with NSAIDs using X-ray crystallography and to relate ligand binding modes to effects on receptor activity. We find that several NSAIDs (sulindac sulfide, diclofenac, indomethacin and ibuprofen) bind PPARγ and modulate PPARγ activity at pharmacologically relevant concentrations. Diclofenac acts as a partial agonist and binds to the PPARγ ligand binding pocket (LBP) in typical partial agonist mode, near the β-sheets and helix 3. By contrast, two copies of indomethacin and sulindac sulfide bind the LBP and, in aggregate, these ligands engage in LBP contacts that resemble agonists. Accordingly, both compounds, and ibuprofen, act as strong partial agonists. Assessment of NSAID activities in PPARγ-dependent 3T3-L1 cells reveals that NSAIDs display adipogenic activities and exclusively regulate PPARγ-dependent target genes in a manner that is consistent with their observed binding modes. Further, PPARγ knockdown eliminates indomethacin activities at selected endogenous genes, confirming receptor-dependence of observed effects. We propose that it is important to consider how individual NSAIDs interact with PPARγ to understand their activities, and that it will be interesting to determine whether high dose NSAID therapies result in PPAR activation.

The Effects of Naproxen on Chondrogenesis of Human Mesenchymal Stem Cells

Currently, there are no established treatments to prevent, stop, or even retard the degeneration of articular cartilage in osteoarthritis (OA). Biological repair of the degenerating articular cartilage would be preferable to surgery. There is no benign site where autologous chondrocytes can be harvested and used as a cell source for cartilage repair, leaving mesenchymal stem cells (MSCs) as an attractive option. However, MSCs from OA patients have been shown to constitutively express collagen type X (COL-X), a marker of late-stage chondrocyte hypertrophy. We recently found that naproxen (Npx), but not other nonsteroidal anti-inflammatory drugs, can induce collagen type X alpha 1 (COL10A1) gene expression in bone marrow-derived MSCs from healthy and OA donors. In this study, we determined the effect of Npx on COL10A1 expression and investigated the intracellular signaling pathways that mediate such effect in normal human MSCs during chondrogenesis. MSCs were cultured in standard chondrogenic differentiation media supplemented with or without Npx. Our results show that Npx can regulate chondrogenic differentiation by affecting the gene expression of both Indian hedgehog and parathyroid hormone/parathyroid hormone-related protein signaling pathways in a time-dependent manner, suggesting a complex interaction of different signaling pathways during the process.

Wharton's jelly derived mesenchymal stem cells: future of regenerative medicine? Recent findings and clinical significance

Around 5 million annual births in EU and 131 million worldwide give a unique opportunity to collect lifesaving Wharton's jelly derived mesenchymal stem cells (WJ-MSC). Evidences that these cells possess therapeutic properties are constantly accumulating. Collection of WJ-MSC is done at the time of delivery and it is easy and devoid of side effects associated with collection of adult stem cells from bone marrow or adipose tissue. Likewise, their rate of proliferation, immune privileged status, lack of ethical concerns, nontumorigenic properties make them ideal for both autologous and allogeneic use in regenerative medicine applications. This review provides an outline of the recent findings related to WJ-MSC therapeutic effects and possible advantage they possess over MSC from other sources. Results of first clinical trials conducted to treat immune disorders are highlighted.

Human mesenchymal stem cells as a novel platform for simultaneous evaluation of cytotoxicity and genotoxicity of pharmaceuticals

The in vitro micronucleus test is a well-known test for the screening of genotoxic compounds. However until now, most studies have been performed on either human peripheral lymphocytes or established cancer cell lines. This study provides human mesenchymal stem cells as an alternative to the conventional micronucleus test. We grew umbilical cord mesenchymal stem cells (UC-MSCs) on coverslips eliminating the cumbersome technique involving hypotonic treatment, fixation and preparing smears required for suspension culture (lymphocytes). The background frequency of nuclear blebs and micronuclei in UC-MSCs was found to be 7±5, in lymphocytes 16±3.5 and 9±3 and that for A549 cell line was 65±5 and 15±5 per 1000 cells, respectively, suggesting differences in the repair mechanism of normal and cancer cell lines. We inspected the cytotoxic and genotoxic effects of two known mutagens, mitomycin-C and hydrogen peroxide (H2O2), on UC-MSCs, lymphocytes and A549 cells. Treatment with mitomycin-C and H2O2 demonstrated drastic differences in the degree of cytotoxicity and genotoxicity suggesting a constitutional difference between normal and cancer cells. In addition we tested two solvents, dimethyl sulfoxide (DMSO) and ethanol, and two drugs, metformin and rapamycin. DMSO above 1% was found to be cytotoxic and genotoxic, whereas ethanol at same concentration was neither cytotoxic nor genotoxic indicating the minimal non-toxic level of the solvents. This study thus offers UC-MSCs as a better substitute to peripheral lymphocytes and cancer cell lines for high throughput screening of compounds and reducing the animal studies.

Bupivacaine mandibular nerve block affects intraoperative blood pressure and heart rate in a Yucatan miniature swine mandibular condylectomy model: a pilot study

PURPOSE/AIM

The primary objective was to evaluate the effect of a bupivacaine mandibular nerve block on intraoperative blood pressure (BP) and heart rate (HR) in response to surgical stimulation and the need for systemic analgesics postoperatively. We hypothesized that a mandibular nerve block would decrease the need for systemic analgesics both intraoperatively and postoperatively.

MATERIALS AND METHODS

Fourteen adult male Yucatan pigs were purchased. Pigs were chemically restrained with ketamine, midazolam, and dexmedetomidine and anesthesia was maintained with isoflurane inhalant anesthesia. Pigs were randomized to receive a mandibular block with either bupivacaine (bupivacaine group) or saline (control group). A nerve stimulator was used for administration of the block with observation of masseter muscle twitch to indicate the injection site. Invasive BP and HR were measured with the aid of an arterial catheter in eight pigs. A rescue analgesic protocol consisting of fentanyl and lidocaine was administered if HR or BP values increased 20% from baseline. Postoperative pain was quantified with a customized ethogram. HR and BP were evaluated at base line, pre-rescue, 10 and 20 min post-rescue.

RESULTS

Pre-rescue mean BP was significantly increased (p = .001) for the bupivacaine group. Mean intraoperative HR was significantly lower (p = .044) in the bupivacaine versus saline group. All other parameters were not significant.

CONCLUSION

Addition of a mandibular nerve block to the anesthetic regimen in the miniature pig condylectomy model may improve variations in intraoperative BP and HR. This study establishes the foundation for future studies with larger animal numbers to confirm these preliminary findings.

Ability of bone graft substitutes to support the osteoprogenitor cells: An in-vitro study

AIM: To compare seven commercially available bone graft substitutes (BGS) in terms of these properties and without using any additional biological growth factors.

METHODS: Porcine osteoprogenitor cells were loaded on seven commercially available BGS and allowed to proliferate for one week followed by osteogenic induction. Staining for live/dead cells as well as scanning electron microscopy (SEM) was carried out to determine viability and cellular binding. Further outcome measures included alkaline phosphatase (ALP) assays with normalisation for DNA content to quantify osteogenic potential. Negative and positive control experiments were carried out in parallel to validate the results.

RESULTS: Live/dead and SEM imaging showed higher viability and attachment with β-tricalcium phosphate (β-TCP) than with other BGS (P < 0.05). The average ALP activity in nmol/mL (normalised value for DNA content in nmol/μg DNA) per sample was 657.58 (132.03) for β-TCP, 36.22 (unable to normalise) for calcium sulphate, 19.93 (11.39) for the Hydroxyapatite/Tricalcium Phosphate composite, 14.79 (18.53) for polygraft, 13.98 (8.15) for the highly porous β-Tricalcium Phosphate, 5.56 (10.0) for polymers, and 3.82 (3.8) for Hydroxyapatite.

CONCLUSION: Under the above experimental conditions, β-TCP was able to maintain better the viability of osteoprogenitor cells and allow proliferation and differentiation (P < 0.05).

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.

Tissue-engineered cartilage with inducible and tunable immunomodulatory properties

The pathogenesis of osteoarthritis is mediated in part by inflammatory cytokines including interleukin-1 (IL-1), which promote degradation of articular cartilage and prevent human mesenchymal stem cell (MSC) chondrogenesis. In this study, we combined gene therapy and functional tissue engineering to develop engineered cartilage with immunomodulatory properties that allow chondrogenesis in the presence of pathologic levels of IL-1 by inducing overexpression of IL-1 receptor antagonist (IL-1Ra) in MSCs via scaffold-mediated lentiviral gene delivery. A doxycycline-inducible vector was used to transduce MSCs in monolayer or within 3D woven PCL scaffolds to enable tunable IL-1Ra production. In the presence of IL-1, IL-1Ra-expressing engineered cartilage produced cartilage-specific extracellular matrix, while resisting IL-1-induced upregulation of matrix metalloproteinases and maintaining mechanical properties similar to native articular cartilage. The ability of functional engineered cartilage to deliver tunable anti-inflammatory cytokines to the joint may enhance the long-term success of therapies for cartilage injuries or osteoarthritis.

NSAID therapy effects on healing of bone, tendon, and the enthesis

Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used for the treatment of skeletal injuries. The ability of NSAIDs to reduce pain and inflammation is well-established. However, the effects of NSAID therapy on healing of skeletal injuries is less defined. NSAIDs inhibit cyclooxygenase activity to reduce synthesis of prostaglandins, which are proinflammatory, lipid-signaling molecules. Inhibition of cyclooxygenase activity can impact many physiological processes. The effects of NSAID therapy on healing of bone, tendon, and the tendon-to-bone junction (enthesis) have been studied in animal and cell culture models, but human studies are few. Use of different NSAIDs with different pharmacological properties, differences in dosing regimens, and differences in study models and outcome measures have complicated comparisons between studies. In this review, we summarize the mechanisms by which bone, tendon, and enthesis healing occurs, and describe the effects of NSAID therapy on each of these processes. Determining the impact of NSAID therapy on healing of skeletal tissues will enable clinicians to appropriately manage the patient's condition and improve healing outcomes.

Do nonsteroidal anti-inflammatory drugs affect bone healing? A critical analysis

Nonsteroidal anti-inflammatory drugs (NSAIDs) play an essential part in our approach to control pain in the posttraumatic setting. Over the last decades, several studies suggested that NSAIDs interfere with bone healing while others contradict these findings. Although their analgesic potency is well proven, clinicians remain puzzled over the potential safety issues. We have systematically reviewed the available literature, analyzing and presenting the available in vitro animal and clinical studies on this field. Our comprehensive review reveals the great diversity of the presented data in all groups of studies. Animal and in vitro studies present so conflicting data that even studies with identical parameters have opposing results. Basic science research defining the exact mechanism with which NSAIDs could interfere with bone cells and also the conduction of well-randomized prospective clinical trials are warranted. In the absence of robust clinical or scientific evidence, clinicians should treat NSAIDs as a risk factor for bone healing impairment, and their administration should be avoided in high-risk patients.

Treatment with paracetamol, ketorolac or etoricoxib did not hinder alveolar bone healing: a histometric study in rats

Prostaglandins control osteoblastic and osteoclastic function under physiological or pathological conditions and are important modulators of the bone healing process. The non-steroidal anti-inflammatory drugs (NSAIDs) inhibit cyclooxygenase (COX) activity and consequently prostaglandins synthesis. Experimental and clinical evidence has indicated a risk for reparative bone formation related to the use of non-selective (COX-1 and COX-2) and COX-2 selective NSAIDs. Ketorolac is a non-selective NSAID which, at low doses, has a preferential COX-1 inhibitory effect and etoricoxib is a new selective COX-2 inhibitor. Although literature data have suggested that ketorolac can interfere negatively with long bone fracture healing, there seems to be no study associating etoricoxib with reparative bone formation. Paracetamol/acetaminophen, one of the first choices for pain control in clinical dentistry, has been considered a weak anti-inflammatory drug, although supposedly capable of inhibiting COX-2 activity in inflammatory sites.