Various types of cellular injection have become a popular and costly treatment option for patients with knee osteoarthritis despite a paucity of literature establishing relative efficacy to each other or corticosteroid injections. Here we aimed to identify the safety and efficacy of cell injections from autologous bone marrow aspirate concentrate, autologous adipose stromal vascular fraction and allogeneic human umbilical cord tissue-derived mesenchymal stromal cells, in comparison to corticosteroid injection (CSI). The study was a phase 2/3, four-arm parallel, multicenter, single-blind, randomized, controlled clinical trial with 480 patients with a diagnosis of knee osteoarthritis (Kellgren–Lawrence II–IV). Participants were randomized to the three different arms with a 3:1 distribution. Arm 1: autologous bone marrow aspirate concentrate (n = 120), CSI (n = 40); arm 2: umbilical cord tissue-derived mesenchymal stromal cells (n = 120), CSI (n = 40); arm 3: stromal vascular fraction (n = 120), CSI (n = 40). The co-primary endpoints were the visual analog scale pain score and Knee injury and Osteoarthritis Outcome Score pain score at 12 months versus baseline. Analyses of our primary endpoints, with 440 patients, revealed that at 1 year post injection, none of the three orthobiologic injections was superior to another, or to the CSI control. In addition, none of the four groups showed a significant change in magnetic resonance imaging osteoarthritis score compared to baseline. No procedure-related serious adverse events were reported during the study period. In summary, this study shows that at 1 year post injection, there was no superior orthobiologic as compared to CSI for knee osteoarthritis. ClinicalTrials.gov Identifier: NCT03818737
Background: The clinical healing environment after a posterior spinal arthrodesis surgery is one of the most clinically challenging bone-healing environments across all orthopedic interventions due to the absence of a contained space and the need to form de novo bone. Our group has previously reported that sclerostin in expressed locally at high levels throughout a developing spinal fusion. However, the role of sclerostin in controlling bone fusion remains to be established. Methods: We computationally identified two FDA-approved drugs, as well as a single novel small-molecule drug, for their ability to disrupt the interaction between sclerostin and its receptor, LRP5/6. The drugs were tested in several in vitro biochemical assays using murine MC3T3 and MSCs, assessing their ability to (1) enhance canonical Wnt signaling, (2) promote the accumulation of the active (non-phosphorylated) form of β-catenin, and (3) enhance the intensity and signaling duration of BMP signaling. These drugs were then tested subcutaneously in rats as standalone osteoinductive agents on plain collagen sponges. Finally, the top drug candidates (called VA1 and C07) were tested in a rabbit posterolateral spine fusion model for their ability to achieve a successful fusion at 6 wk. Results: We show that by controlling GSK3b phosphorylation our three small-molecule inhibitors (SMIs) simultaneously enhance canonical Wnt signaling and potentiate canonical BMP signaling intensity and duration. We also demonstrate that the SMIs produce dose-dependent ectopic mineralization in vivo in rats as well as significantly increase posterolateral spine fusion rates in rabbits in vivo, both as standalone osteogenic drugs and in combination with autologous iliac crest bone graft. Conclusions: Few if any osteogenic small molecules possess the osteoinductive potency of BMP itself - that is, the ability to form de novo ectopic bone as a standalone agent. Herein, we describe two such SMIs that have this unique ability and were shown to induce de novo bone in a stringent in vivo environment. These SMIs may have the potential to be used in novel, cost-effective bone graft substitutes for either achieving spinal fusion or in the healing of critical-sized fracture defects.
Osteoinductive bone morphogenetic proteins (BMPs), including BMP-2, have a unique capability of mediating bone formation both in orthotopic and ectopic locations. Immunosuppresive macrolides have been shown to potentiate BMP-2 activity through FKBP12, but these have yet to translate to effective osteoinductive therapies. Herein, we show the osteogenic activity of FK506 as a stand-alone agent in direct comparison to BMP-2 both in vitro and in vivo. FK506 was capable of producing stand-alone alkaline phosphatase induction in C2C12 cells comparable to that seen with rhBMP-2. FK506 treatment activated the BMP receptor, as shown by increased pSmad1/5 levels, and produced significantly higher mRNA levels of the early response genes in BMP and TGF-β pathways. Additionally, the FK506 induction of alkaline phosphatase was shown to be resistant to Noggin treatment. In vivo osteogenic activity of FK506 was tested by local delivery on a collagen sponge in an ectopic subcutaneous implantation model in the rat. Dose responses of FK506 showed increasing levels of ectopic mineralization comparable to the mineral volume produced by BMP-2 delivery. These findings suggest that the use of FK506 can enhance osteoblastic differentiation in vitro and can induce mineralization when delivered locally in vivo.
Background: During the COVID-19 pandemic, prioritization of care and utilization of scarce resources are daily considerations in healthcare systems that have never experienced these issues before. Elective surgical cases have been largely postponed, and surgery departments are struggling to correctly and equitably determine which cases need to proceed. A resource to objectively prioritize and track time sensitive cases would be useful as an adjunct to clinical decision-making. Methods: A multidisciplinary working group at Emory Healthcare developed and implemented an adjudication tool for the prioritization of time sensitive surgeries. The variables identified by the team to form the construct focused on the patient’s survivability according to actuarial data, potential impact on function with delay in care, and high-level biology of disease. Implementation of the prioritization was accomplished with a database design to streamline needed communication between surgeons and surgical adjudicators. All patients who underwent time sensitive surgery between 4/10/20 and 6/15/20 across 5 campuses were included. Results: The primary outcomes of interest were calculated patient prioritization score and number of days until operation. 1767 cases were adjudicated during the specified time period. The distribution of prioritization scores was normal, such that real-time adjustment of the empiric algorithm was not required. On retrospective review, as the patient prioritization score increased, the number of days to the operating room decreased. This confirmed the functionality of the tool and provided a framework for organization across multiple campuses. Conclusions: We developed an in-house adjudication tool to aid in the prioritization of a large cohort of canceled and time sensitive surgeries. The tool is relatively simple in its design, reproducible, and data driven which allows for an objective adjunct to clinical decision-making. The database design was instrumental in communication optimization during this chaotic period for patients and surgeons.
Introduction. Historically, a majority of prosthetic joint infections (PJIs) grew Gram-positive bacteria. While previous studies stratified PJI risk with specific organisms by patient comorbidities, we compared infection rates and microbiologic characteristics of PJIs by hospital setting: a dedicated orthopaedic hospital versus a general hospital serving multiple surgical specialties. Methods. A retrospective review of prospectively collected data on 11,842 consecutive primary hip and knee arthroplasty patients was performed. Arthroplasty cases performed between April 2006 and August 2008 at the general university hospital serving multiple surgical specialties were compared to cases at a single orthopaedic specialty hospital from September 2008 to August 2016. Results. The general university hospital PJI incidence rate was 1.43%, with 5.3% of infections from Gram-negative species. In comparison, at the dedicated orthopaedic hospital, the overall PJI incidence rate was substantially reduced to 0.75% over the 8-year timeframe. Comparing the final two years of practice at the general university facility to the most recent two years at the dedicated orthopaedics hospital, the PJI incidence was significantly reduced (1.43% vs 0.61%). Though the overall number of infections was reduced, there was a significantly higher proportion of Gram-negative infections over the 8-year timeframe at 25.3%. Conclusion. In transitioning from a multispecialty university hospital to a dedicated orthopaedic hospital, the PJI incidence has been significantly reduced despite a greater Gram-negative proportion (25.3% versus 5.3%). These results suggest a change in the microbiologic profile of PJI when transitioning to a dedicated orthopaedic facility and that greater Gram-negative antibiotic coverage could be considered.
The authors wish to make the following corrections to this paper [1]: The author name "Nick J. Willet" should be "Nick J. Willett". We have recently become aware of errors in Section 4.7 of the published paper regarding our ectopic bone formation model. We incorrectly stated that the in vivo subcutaneous implantation model utilized an immunocompromised athymic strain of rats from Harlan Labs; the strain used in the study was Sprague Dawley rats from Charles River Laboratories. Section 4.7 should read as follows. All animal procedures were approved by the local Institutional Animal Care and Use Committee. The FK506 compound was first tested in a standard rat chest ectopic bone formation model using a 5 µg/disc dose of rhBMP-2 as a positive control to induce bone formation consistently. rhBMP-2 or FK506 were loaded with the use of a pipette onto sterile bovine Type-I collagen disks (8 mm in diameter and 3 mm thick; Kensey Nash, Exton, PA, USA) in a biosafety cabinet. The disks were then transported in a sterile container to the surgical operating room. Each implant was loaded with a total volume of 100 uL solution containing 5 µg of rhBMP-2 (Medtronic, Minneapolis, MN, USA) or 100 µL of stock concentrations of 0, 10, 20, 30, and 40 mM of FK506 (corresponding to 0.8, 1.6, 2.4, and 3.2 mg of dry weight, respectively) solubilized in the organic solvent dimethyl sulfoxide (DMSO, Sigma-Aldrich) (n = 4 for each). In a pilot experiment, 10% to 100% DMSO was determined to have no effect on rhBMP-2-induced ectopic bone formation (data not shown). Male Sprague Dawley five to six-week-old rats (Charles River Laboratories, Wilmington, MA, USA) were anesthetized with 3% to 5% isoflurane mixed with oxygen at a flow rate of 0.5 to 1 L/min and maintained during surgery with a dose of 1% to 2%. Surgery was performed with the animal positioned supine on a circulating-water heating pad. Two to four 1 cm transverse incisions were made about 3 cm apart on the chest of each rat, and subcutaneous pockets were created by blunt dissection with scissors. The implants were inserted into the pockets, and closure was accomplished with either 3-0 or 4-0 resorbable sutures (Vicryl; Ethicon, Johnson & Johnson, Somerville, NJ, USA) and/or skin clips. The rats were euthanized four weeks postoperatively. The implants were harvested and evaluated with manual palpation, high-resolution digital radiography, and non-decalcified histological analysis. These corrections do not change the overall outcomes of the study. The incorrect strain that is listed is an immunocompromised animal, whereas we used an immunocompetent strain. This is an important correction given that the drug, FK506, utilized in this study can have an effect on immune cells. The authors would like to apologize for any inconvenience caused to the readers by these changes.
A high rate of symptomatic spinal pseudoarthrosis and a wide range of complications associated with the use of iliac crest bone graft (the gold standard) have prompted the spine surgery community to seek alternative options to promote spinal fusion. Emory University has been one of the global leaders in this endeavor. This invited review covers the last 25 years of Emory’s contributions to translational spine research, focusing specifically on our work with bone morphogenetic proteins (BMP) and the BMP signaling pathway. As a result of this work, recombinant human BMP-2 is the only Food and Drug Administration approved biologic bone graft substitute. It has been shown to significantly increase spinal fusion rates across the spinal column because of its potent ability to stimulate local bone formation through the recruitment of mesenchymal stem cells. This review covers our development of animal models of spinal fusion, our body of work regarding the translation of BMP from the benchtop to the clinic, the discovery of LMP-1 and strategies to enhance cellular responsiveness to BMPs, and the design of various small molecule drugs that can enhance local bone formation.
Development and repair of the skeletal system and other organs are highly dependent on precise regulation of the bone morphogenetic protein (BMP) pathway. The use of BMPs clinically to induce bone formation has been limited in part by the requirement of much higher doses of recombinant proteins in primates than were needed in cell culture or rodents. Therefore, increasing cellular responsiveness to BMPs has become our focus. We determined that an osteogenic LIM mineralization protein, LMP-1 interacts with Smurf1 (Smad ubiquitin regulatory factor 1) and prevents ubiquitination of Smads resulting in potentiation of BMP activity. In the region of LMP-1 responsible for bone formation, there is a motif that directly interacts with the Smurf1 WW2 domain and thus effectively competes for binding with Smad1 and Smad5, key signaling proteins in the BMP pathway. Here we show that the same region also contains a motif that interacts with Jun activation-domain-binding protein 1 (Jab1) which targets a common Smad, Smad4, shared by both the BMP and transforming growth factor-β (TGF-β) pathways, for proteasomal degradation. Jab1 was first identified as a coactivator of the transcription factor c-Jun. Jab1 binds to Smad4, Smad5, and Smad7, key intracellular signaling molecules of the TGF-β superfamily, and causes ubiquitination and/or degradation of these Smads. We confirmed a direct interaction of Jab1 with LMP-1 using recombinantly expressed wild-type and mutant proteins in slot-blot-binding assays. We hypothesized that LMP-1 binding to Jab1 prevents the binding and subsequent degradation of these Smads causing increased accumulation of osteogenic Smads in cells. We identified a sequence motif in LMP-1 that was predicted to interact with Jab1 based on the MAME/MAST sequence analysis of several cellular signaling molecules that are known to interact with Jab-1. We further mutated the potential key interacting residues in LMP-1 and showed loss of binding to Jab1 in binding assays in vitro. The activities of various wild-type and mutant LMP-1 proteins were evaluated using a BMP-responsive luciferase reporter and alkaline phosphatase assay in mouse myoblastic cells that were differentiated toward the osteoblastic phenotype. Finally, to strengthen physiological relevance of LMP-1 and Jab1 interaction, we showed that overexpression of LMP-1 caused nuclear accumulation of Smad4 upon BMP treatment which is reflective of increased Smad signaling in cells.
Background:
The novel coronavirus and associated Coronavirus Disease 2019 (COVID-19) is rapidly spreading throughout the world, with robust growth in the United States. Its drastic impact on the global population and international health care is swift, evolving, and unpredictable. The effects on orthopaedic surgery departments are predominantly indirect, with widespread cessation of all nonessential orthopaedic care. Although this is vital to the system-sustaining measures of isolation and resource reallocation, there is profound detriment to orthopaedic training programs.
Methods:
In the face of new pressures on the finite timeline on an orthopaedic residency, the Emory University School of Medicine Department of Orthopaedics has devised a 5-pronged strategy based on the following: (1) patient and provider safety, (2) uninterrupted necessary care, (3) system sustainability, (4) adaptability, and (5) preservation of vital leadership structures.
Results:
Our 5 tenants support a 2-team system, whereby the residents are divided into cycling “active-duty” and “working remotely” factions. In observation of the potential incubation period of viral symptoms, phase transitions occur every 2 weeks with strict adherence to team assignments. Intrateam redundancy can accommodate potential illness to ensure a stable unit of able residents. Active duty residents participate in in-person surgical encounters and virtual ambulatory encounters, whereas remotely working residents participate in daily video-conferenced faculty-lead, case-based didactics and pursue academic investigation, grant writing, and quality improvement projects. To sustain this, faculty and administrative 2-team systems are also in place to protect the leadership and decision-making components of the department.
Conclusions:
The novel coronavirus has decimated the United States healthcare system, with an unpredictable duration, magnitude, and variability. As collateral damage, orthopaedic residencies are faced with new challenges to provide care and educate residents in the face of safety, resource redistribution, and erosion of classic learning opportunities. Our adaptive approach aims to be a generalizable tactic to optimize our current landscape.
LIM Mineralization Protein-1 (LMP-1) is an intracellular regulator of bone formation and has been shown to be osteoinductive in vitro and in vivo. The effect of LMP-1 on other aspects of bone homeostasis has not been previously studied. In a pilot study we observed that LMP-1 decreased nitric oxide (NO) production in pre-osteoclasts. Here we report a new anti-inflammatory effect of LMP-1 and define its mechanism of action in lipopolysaccharide (LPS)-stimulated RAW 264.7 pre-osteoclasts. We found that LMP-1 significantly inhibited LPS-induced NO production. LMP-1 also effectively inhibited the expression of inducible Nitric Oxide Synthase (iNOS), potently suppressed the transcriptional activity and nuclear translocation of nuclear factor kappa B (NF-κB), and prevented the phosphorylation of inhibitor of kappa B (IκB). Interestingly, LMP-1 had no effect on Receptor-Activator of Nuclear Factor B Ligand (RANKL)-induced activation of NF-κB. Furthermore, LMP-1 had no effect on the LPS-induced phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), whereas it did attenuate the phosphorylation of c-Jun NH2-terminal kinase (JNK) while enhancing phosphorylation of p38 mitogen-activated protein kinases (p38 MAPK). These results suggest that LMP-1 has an anti-inflammatory effect, and this effect is, at least in part, due to the inhibition of NO production by the suppression of NF-κB activation and selective regulation of mitogen-activated protein kinase (MAPK) pathways.