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de Mesy Bentley KL, Galloway CA, Muthukrishnan G, Echternacht SR, Masters EA, Zeiter S, Schwarz EM, Leckenby JI. Emerging electron microscopy and 3D methodologies to interrogate Staphylococcus aureus osteomyelitis in murine models. J Orthop Res 2021; 39:376-388. [PMID: 33377538 PMCID: PMC7885905 DOI: 10.1002/jor.24968] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 11/20/2020] [Accepted: 12/16/2020] [Indexed: 02/04/2023]
Abstract
Recent breakthroughs in our understanding of orthopaedic infections have come from advances in transmission electron microscopy (TEM) imaging of murine models of bone infection, most notably Staphylococcus aureus invasion and colonization of osteocyte-lacuno canalicular networks of live cortical bone during the establishment of chronic osteomyelitis. To further elucidate this microbial pathogenesis and evaluate the mechanism of action of novel interventions, additional advances in TEM imaging are needed. Here we present detailed protocols for fixation, decalcification, and epoxy embedment of bone tissue for standard TEM imaging studies, as well as the application of immunoelectron microscopy to confirm S. aureus occupation within sub-micron canaliculi. We also describe the first application of the novel Automated-Tape-UltraMicrotome system with three-dimensional reconstruction and volumetric analyses to quantify S. aureus occupation within the osteocyte-lacuno canalicular networks. Reconstruction of the three-dimensional volume broadened our perspective of S. aureus colonization of the canalicular network and, surprisingly, revealed adjacent noninfected canaliculi. This observation has led us to hypothesize that viable osteocytes of the osteocyte-lacuno canalicular networks respond and resist infection, opening future research directions to explain the paradox of adjacent uninfected canaliculi and life-long deep bone infection in patients with chronic osteomyelitis.
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Bell RD, Rahimi H, Kenney HM, Lieberman AA, Wood RW, Schwarz EM, Ritchlin CT. Altered Lymphatic Vessel Anatomy and Markedly Diminished Lymph Clearance in Affected Hands of Patients With Active Rheumatoid Arthritis. Arthritis Rheumatol 2021; 72:1447-1455. [PMID: 32420693 DOI: 10.1002/art.41311] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 05/05/2020] [Indexed: 01/17/2023]
Abstract
OBJECTIVE To assess differences between lymphatic function in the affected hands of rheumatoid arthritis (RA) patients with active synovitis and that of healthy controls, using indocyanine green (ICG) dye and near-infrared (NIR) imaging. METHODS NIR imaging of the hands of 8 patients with active RA and 13 healthy controls was performed following web space injection of 0.1 ml of 100 μM ICG. The percentage of ICG retention in the web spaces was determined by NIR imaging at baseline and at 7 days (±1 day) after the initial injections; image analysis provided contraction frequency. ICG+ lymphatic vessel (LV) length and branching architecture were assessed. RESULTS Retention of ICG in RA hands was higher compared to controls (P < 0.01). The average contraction frequency of ICG+ LVs in RA patients and in controls did not differ (mean ± SD 0.53 ± 0.39 contractions/minute versus 0.51 ± 0.35 contractions/minute). Total ICG+ LV length in RA hands was lower compared to healthy controls (58.3 ± 15.0 cm versus 71.4 ± 16.1 cm; P < 0.001), concomitant with a decrease in the number of ICG+ basilic LVs in the hands of RA patients (P < 0.05). CONCLUSION Lymphatic drainage in the hands of RA patients with active disease was reduced compared to controls. This reduction was associated with a decrease in total length of ICG+ LVs on the dorsal surface of the hands, which continued to contract at a similar rate to that observed in controls. These findings provide a plausible mechanism for exacerbation of synovitis and joint damage, specifically the accumulation and retention of inflammatory cells and catabolic factors in RA joints due to impaired efferent lymphatic flow. NIR/ICG imaging of RA hands is feasible and warrants formal investigation as a primary outcome measure for arthritis disease severity and/or persistence in future clinical trials.
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Metsemakers WJ, Zalavras C, Schwarz EM, Chen AF, Trampuz A, Moriarty TF. Antimicrobial Resistance, the COVID-19 Pandemic, and Lessons for the Orthopaedic Community. J Bone Joint Surg Am 2021; 103:4-9. [PMID: 33259429 DOI: 10.2106/jbjs.20.01214] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Antimicrobial resistance (AMR) is widely regarded as one of the most important global public health challenges of the twenty-first century. The overuse and the improper use of antibiotics in human medicine, food production, and the environment as a whole have unfortunately contributed to this issue. Many major international scientific, political, and social organizations have warned that the increase in AMR could cost the lives of millions of people if it is not addressed on a global scale. Although AMR is already a challenge in clinical practice today, it has taken on a new importance in the face of the coronavirus disease 2019 (COVID-19) pandemic. While improved handwashing techniques, social distancing, and other interventional measures may positively influence AMR, the widespread use of antibiotics to treat or prevent bacterial coinfections, especially in unconfirmed cases of COVID-19, may have unintended negative implications with respect to AMR. Although the exact number of bacterial coinfections and the rate at which patients with COVID-19 receive antibiotic therapy remain to be accurately determined, the pandemic has revived the discussion on antibiotic overuse and AMR. This article describes why the COVID-19 pandemic has increased our awareness of AMR and presents the immense global impact of AMR on society as a whole. Furthermore, an attempt is made to stress the importance of tackling AMR in the future and the role of the orthopaedic community in this worldwide effort.
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Kates SL, Owen JR, Beck CA, Xie C, Muthukrishnan G, Daiss JL, Schwarz EM. Lack of Humoral Immunity Against Glucosaminidase Is Associated with Postoperative Complications in Staphylococcus aureus Osteomyelitis. J Bone Joint Surg Am 2020; 102:1842-1848. [PMID: 32858560 PMCID: PMC9018051 DOI: 10.2106/jbjs.20.00029] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Glucosaminidase (Gmd) is known to be a protective antigen in animal models of Staphylococcus aureus osteomyelitis. We compared the endogenous anti-Gmd antibody levels in sera of patients with culture-confirmed S. aureus bone infections to their sera at 1 year after operative treatment of the infection. METHODS A novel global biospecimen registry of 297 patients with deep-wound culture-confirmed S. aureus osteomyelitis was analyzed to assess relationships between baseline anti-Gmd serum titers (via custom Luminex assay), known host risk factors for infection, and 1-year postoperative clinical outcomes (e.g., infection control, inconclusive, refracture, persistent infection, septic nonunion, amputation, and septic death). RESULTS All patients had measurable humoral immunity against some S. aureus antigens, but only 20 patients (6.7%; p < 0.0001) had high levels of anti-Gmd antibodies (>10 ng/mL) in serum at baseline. A subset of 194 patients (65.3%) who completed 1 year of follow-up was divided into groups based on anti-Gmd level: low (<1 ng/mL, 54 patients; 27.8%), intermediate (<10 ng/mL, 122 patients; 62.9%), and high (>10 ng/mL, 18 patients; 9.3%), and infection control rates were 40.7%, 50.0%, and 66.7%, respectively. The incidence of adverse outcomes in these groups was 33.3%, 16.4%, and 11.1%, respectively. Assessing anti-Gmd level as a continuous variable showed a 60% reduction in adverse-event odds (p = 0.04) for every tenfold increase in concentration. No differences in patient demographics, body mass index of >40 kg/m, diabetes status, age of ≥70 years, male sex, Charlson Comorbidity Index of >1, or Cierny-Mader host type were observed between groups, and these risk factors were not associated with adverse events. Patients with low anti-Gmd titer demonstrated a significant 2.68-fold increased odds of adverse outcomes (p = 0.008). CONCLUSIONS Deficiency in circulating anti-Gmd antibodies was associated serious adverse outcomes following operative treatment of S. aureus osteomyelitis. At 1 year, high levels of anti-Gmd antibodies were associated with a nearly 3-fold increase in infection-control odds. Additional prospective studies clarifying Gmd immunization for osteomyelitis are needed. LEVEL OF EVIDENCE Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.
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Kenney HM, Bell RD, Masters EA, Xing L, Ritchlin CT, Schwarz EM. Lineage tracing reveals evidence of a popliteal lymphatic muscle progenitor cell that is distinct from skeletal and vascular muscle progenitors. Sci Rep 2020; 10:18088. [PMID: 33093635 PMCID: PMC7581810 DOI: 10.1038/s41598-020-75190-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Accepted: 10/12/2020] [Indexed: 12/31/2022] Open
Abstract
Loss of popliteal lymphatic vessel (PLV) contractions, which is associated with damage to lymphatic muscle cells (LMCs), is a biomarker of disease progression in mice with inflammatory arthritis. Currently, the nature of LMC progenitors has yet to be formally described. Thus, we aimed to characterize the progenitors of PLV-LMCs during murine development, towards rational therapies that target their proliferation, recruitment, and differentiation onto PLVs. Since LMCs have been described as a hybrid phenotype of striated and vascular smooth muscle cells (VSMCs), we performed lineage tracing studies in mice to further clarify this enigma by investigating LMC progenitor contribution to PLVs in neonatal mice. PLVs from Cre-tdTomato reporter mice specific for progenitors of skeletal myocytes (Pax7+ and MyoD+) and VSMCs (Prrx1+ and NG2+) were analyzed via whole mount immunofluorescent microscopy. The results showed that PLV-LMCs do not derive from skeletal muscle progenitors. Rather, PLV-LMCs originate from Pax7-/MyoD-/Prrx1+/NG2+ progenitors similar to VSMCs prior to postnatal day 10 (P10), and from a previously unknown Pax7-/MyoD-/Prrx1+/NG2- muscle progenitor pathway during development after P10. Future studies of these LMC progenitors during maintenance and repair of PLVs, along with their function in other lymphatic beds, are warranted.
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Masters EA, de Mesy Bentley KL, Gill AL, Hao SP, Galloway CA, Salminen AT, Guy DR, McGrath JL, Awad HA, Gill SR, Schwarz EM. Identification of Penicillin Binding Protein 4 (PBP4) as a critical factor for Staphylococcus aureus bone invasion during osteomyelitis in mice. PLoS Pathog 2020; 16:e1008988. [PMID: 33091079 PMCID: PMC7608983 DOI: 10.1371/journal.ppat.1008988] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 11/03/2020] [Accepted: 09/17/2020] [Indexed: 12/03/2022] Open
Abstract
Staphylococcus aureus infection of bone is challenging to treat because it colonizes the osteocyte lacuno-canalicular network (OLCN) of cortical bone. To elucidate factors involved in OLCN invasion and identify novel drug targets, we completed a hypothesis-driven screen of 24 S. aureus transposon insertion mutant strains for their ability to propagate through 0.5 μm-sized pores in the Microfluidic Silicon Membrane Canalicular Arrays (μSiM-CA), developed to model S. aureus invasion of the OLCN. This screen identified the uncanonical S. aureus transpeptidase, penicillin binding protein 4 (PBP4), as a necessary gene for S. aureus deformation and propagation through nanopores. In vivo studies revealed that Δpbp4 infected tibiae treated with vancomycin showed a significant 12-fold reduction in bacterial load compared to WT infected tibiae treated with vancomycin (p<0.05). Additionally, Δpbp4 infected tibiae displayed a remarkable decrease in pathogenic bone-loss at the implant site with and without vancomycin therapy. Most importantly, Δpbp4 S. aureus failed to invade and colonize the OLCN despite high bacterial loads on the implant and in adjacent tissues. Together, these results demonstrate that PBP4 is required for S. aureus colonization of the OLCN and suggest that inhibitors may be synergistic with standard of care antibiotics ineffective against bacteria within the OLCN. Staphylococcus aureus is the most prevalent pathogen in osteomyelitis, and its infection of bone is difficult to cure. S. aureus colonization of the osteocyte lacuno-canalicular network (OLCN) of cortical bone has been identified as a novel pathogenetic mechanism in chronic osteomyelitis. To elucidate factors involved in OLCN invasion, we conducted an in vitro genetic screen that identified pbp4 as a critical gene for S. aureus cell deformation and propagation through nanopores and demonstrated that PBP4 is critical for OLCN colonization in murine osteomyelitis. Thus, PBP4 inhibitors may be novel drugs to treat osteomyelitis in combination with standard of care antibiotics.
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Nishitani K, Ishikawa M, Morita Y, Yokogawa N, Xie C, de Mesy Bentley KL, Ito H, Kates SL, Daiss JL, Schwarz EM. IsdB antibody-mediated sepsis following S. aureus surgical site infection. JCI Insight 2020; 5:141164. [PMID: 33004694 PMCID: PMC7566716 DOI: 10.1172/jci.insight.141164] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 08/26/2020] [Indexed: 12/18/2022] Open
Abstract
Staphylococcus aureus is prevalent in surgical site infections (SSI) and leads to death in approximately 1% of patients. Phase IIB/III clinical trial results have demonstrated that vaccination against the iron-regulated surface determinant protein B (IsdB) is associated with an increased mortality rate in patients with SSI. Thus, we hypothesized that S. aureus induces nonneutralizing anti-IsdB antibodies, which facilitate bacterial entry into leukocytes to generate "Trojan horse" leukocytes that disseminate the pathogen. Since hemoglobin (Hb) is the primary target of IsdB, and abundant Hb-haptoglobin (Hb-Hp) complexes in bleeding surgical wounds are normally cleared via CD163-mediated endocytosis by macrophages, we investigated this mechanism in vitro and in vivo. Our results demonstrate that active and passive IsdB immunization of mice renders them susceptible to sepsis following SSI. We also found that a multimolecular complex containing S. aureus protein A-anti-IsdB-IsdB-Hb-Hp mediates CD163-dependent bacterial internalization of macrophages in vitro. Moreover, IsdB-immunized CD163-/- mice are resistant to sepsis following S. aureus SSI, as are normal healthy mice given anti-CD163-neutralizing antibodies. These genetic and biologic CD163 deficiencies did not exacerbate local infection. Thus, anti-IsdB antibodies are a risk factor for S. aureus sepsis following SSI, and disruption of the multimolecular complex and/or CD163 blockade may intervene.
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MESH Headings
- Animals
- Antibodies, Bacterial/adverse effects
- Antibodies, Monoclonal/adverse effects
- Antigens, CD/immunology
- Antigens, CD/metabolism
- Antigens, Differentiation, Myelomonocytic/immunology
- Antigens, Differentiation, Myelomonocytic/metabolism
- Cation Transport Proteins/immunology
- Female
- Haptoglobins/immunology
- Haptoglobins/metabolism
- Hemoglobins/immunology
- Hemoglobins/metabolism
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Receptors, Cell Surface/immunology
- Receptors, Cell Surface/metabolism
- Sepsis/etiology
- Sepsis/metabolism
- Sepsis/pathology
- Staphylococcal Infections/complications
- Staphylococcal Infections/immunology
- Staphylococcal Infections/microbiology
- Staphylococcus aureus/immunology
- Surgical Wound Infection/complications
- Surgical Wound Infection/immunology
- Surgical Wound Infection/microbiology
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Bell RD, White RJ, Garcia-Hernandez ML, Wu E, Rahimi H, Marangoni RG, Slattery P, Duemmel S, Nuzzo M, Huertas N, Yee M, O’Reilly MA, Morrell C, Ritchlin CT, Schwarz EM, Korman BD. Tumor Necrosis Factor Induces Obliterative Pulmonary Vascular Disease in a Novel Model of Connective Tissue Disease-Associated Pulmonary Arterial Hypertension. Arthritis Rheumatol 2020; 72:1759-1770. [PMID: 32388926 PMCID: PMC7652720 DOI: 10.1002/art.41309] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 05/05/2020] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Connective tissue disease (CTD)-associated pulmonary arterial hypertension (PAH) is the second most common etiology of PAH and carries a poor prognosis. Recently, it has been shown that female human tumor necrosis factor (TNF)-transgenic (Tg) mice die of cardiopulmonary disease by 6 months of age. This study was undertaken to characterize this pathophysiology and assess its potential as a novel model of CTD-PAH. METHODS Histologic analysis was performed on TNF-Tg and wild-type (WT) mice to characterize pulmonary vascular and right ventricular (RV) pathology (n = 40 [4-5 mice per group per time point]). Mice underwent right-sided heart catheterization (n = 29) and micro-computed tomographic angiography (n = 8) to assess vascular disease. Bone marrow chimeric mice (n = 12), and anti-TNF-treated mice versus placebo-treated mice (n = 12), were assessed. RNA sequencing was performed on mouse lung tissue (n = 6). RESULTS TNF-Tg mice displayed a pulmonary vasculopathy marked by collagen deposition (P < 0.001) and vascular occlusion (P < 0.001) with associated RV hypertrophy (P < 0.001) and severely increased RV systolic pressure (mean ± SD 75.1 ± 19.3 mm Hg versus 26.7 ± 1.7 mm Hg in WT animals; P < 0.0001). TNF-Tg mice had increased α-smooth muscle actin (α-SMA) staining, which corresponded to proliferation and loss of von Willebrand factor (vWF)-positive endothelial cells (P < 0.01). There was an increase in α-SMA-positive, vWF-positive cells (P < 0.01), implicating endothelial-mesenchymal transition. Bone marrow chimera experiments revealed that mesenchymal but not bone marrow-derived cells are necessary to drive this process. Treatment with anti-TNF therapy halted the progression of disease. This pathology closely mimics human CTD-PAH, in which patient lungs demonstrate increased TNF signaling and significant similarities in genomic pathway dysregulation. CONCLUSION The TNF-Tg mouse represents a novel model of CTD-PAH, recapitulates key disease features, and can serve as a valuable tool for discovery and assessment of therapeutics.
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Pelled G, Lieber R, Avalos P, Cohn-Yakubovich D, Tawackoli W, Roth J, Knapp E, Schwarz EM, Awad HA, Gazit D, Gazit Z. Teriparatide (recombinant parathyroid hormone 1-34) enhances bone allograft integration in a clinically relevant pig model of segmental mandibulectomy. J Tissue Eng Regen Med 2020; 14:1037-1049. [PMID: 32483878 PMCID: PMC7429307 DOI: 10.1002/term.3075] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 05/14/2020] [Accepted: 05/15/2020] [Indexed: 02/02/2023]
Abstract
Massive craniofacial bone loss poses a clinical challenge to maxillofacial surgeons. Structural bone allografts are readily available at tissue banks but are rarely used due to a high failure rate. Previous studies showed that intermittent administration of recombinant parathyroid hormone (rPTH) enhanced integration of allografts in a murine model of calvarial bone defect. To evaluate its translational potential, the hypothesis that rPTH would enhance healing of a mandibular allograft in a clinically relevant large animal model of mandibulectomy was tested. Porcine bone allografts were implanted into a 5-cm-long continuous mandible bone defect in six adult Yucatan minipigs, which were randomized to daily intramuscular injections of rPTH (1.75 μg/kg) and placebo (n = 3). Blood tests were performed on Day 56 preoperation, Day 0 and on Day 56 postoperation. Eight weeks after the surgery, bone healing was analyzed using high-resolution X-ray imaging (Faxitron and micro computed tomography [CT]) and three-point bending biomechanical testing. The results showed a significant 2.6-fold rPTH-induced increase in bone formation (p = 0.02). Biomechanically, the yield failure properties of the healed mandibles were significantly higher in the rPTH group (yield load: p < 0.05; energy to yield: p < 0.01), and the post-yield displacement and energy were higher in the placebo group (p < 0.05), suggesting increased mineralized integration of the allograft in the rPTH group. In contrast to similar rPTH therapy studies in dogs, no signs of hypercalcemia, hyperphosphatemia, or inflammation were detected. Taken together, we provide initial evidence that rPTH treatment enhances mandibular allograft healing in a clinically relevant large animal model.
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Cole CL, Vasalos K, Nicandri G, Apt C, Osterling E, Ferrara Z, Maloney MD, Schwarz EM, Rizzone K. Use of Fitbit Data to Evaluate the Effects of an Athletic Performance and Injury Prevention Training Program on Daily Physical Levels in Underrepresented Minority Female High School Athletes: A Prospective Study. ORTHOPEDICS AND SPORTS MEDICINE : OPEN ACCESS JOURNAL 2020; 4:370-376. [PMID: 33163966 PMCID: PMC7643901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A marginal number of adolescents meet the recommended guidelines of 60 minutes of moderate to vigorous daily physical activity, and even fewer underrepresented minority females achieve this metric as compared to their male and white counterparts. While potential interventions exist to address these low levels of activity, which is a known risk for acute injuries and chronic disease, there is lack of consensus on the devices used to measure the intensity of daily activity levels. Wearable activity trackers such as Fitbit™ have been utilized to quantify human motion and exercise intensity, but there is little precedence for these measures being assessed in adolescent wearers. Thus, our objective was to assess the feasibility of using Fitbit to assess daily physical activity levels in underrepresented minority adolescent females, who attend an economically challenged urban high school, over the course of a physical activity intervention. We also aimed to identify candidate Fitbit outcome measures for future prospective studies. A 10-week physical activity intervention was implemented in a cohort of 24 high school female athletes. From within this cohort, a sample of five students were provided Fitbit™ devices, from which we obtained data sets from three students. Activity on the days of the exercise intervention was measured and compared to activity on non-intervention days. Post-hoc assessments were performed based on individual heart rate reserves, the predefined levels set by the Inspire Fitbit™ device and the American College of Sports Medicine (ACSM) 2009 guidelines. The results showed that while compliance is challenging, wearable devices can be used to assess daily physical activity levels and intensities in underrepresented minority high school female athletes during an extended physical activity intervention. Of the Fitbit outcomes currently available, assessment of moderate-vigorous activity (min/day) appeared to be the best as a measure of global physical activity. Prospective research is now warranted to validate these thresholds, and to test novel interventions for their ability to transition inactive adolescents at risk of sports-related injuries and long-term chronic disease, into a more active lifestyle.
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Ricciardi BF, Muthukrishnan G, Masters EA, Kaplan N, Daiss JL, Schwarz EM. New developments and future challenges in prevention, diagnosis, and treatment of prosthetic joint infection. J Orthop Res 2020; 38:1423-1435. [PMID: 31965585 PMCID: PMC7304545 DOI: 10.1002/jor.24595] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 01/03/2020] [Indexed: 02/04/2023]
Abstract
Prosthetic joint infection (PJI) is a devastating complication that results in substantial costs to society and patient morbidity. Advancements in our knowledge of this condition have focused on prevention, diagnosis, and treatment, in order to reduce rates of PJI and improve patient outcomes. Preventive measures such as optimization of patient comorbidities, and perioperative antibiotic usage are intensive areas of current clinical research to reduce the rate of PJI. Improved diagnostic tests such as synovial fluid (SF) α-defensin enzyme-linked immunosorbent assay, and nucleic acid-based tests for serum, SF, and tissue cultures, have improved diagnostic accuracy and organism identification. Increasing the diversity of available antibiotic therapy, immunotherapy, and alternative implant coatings remain promising treatments to improve infection eradication in the setting of PJI.
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Cole CL, Vasalos K, Nicandri G, Maloney MD, Schwarz EM. Effects Of Athletic Performance Training On Injury Prevention And Psychosocial Health In Female Adolescent Athletes. Med Sci Sports Exerc 2020. [DOI: 10.1249/01.mss.0000670644.01471.64] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Muthukrishnan G, Soin S, Beck CA, Grier A, Brodell JD, Lee CC, Ackert-Bicknell CL, Lee FEH, Schwarz EM, Daiss JL. A Bioinformatic Approach to Utilize a Patient's Antibody-Secreting Cells against Staphylococcus aureus to Detect Challenging Musculoskeletal Infections. Immunohorizons 2020; 4:339-351. [PMID: 32571786 DOI: 10.4049/immunohorizons.2000024] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 06/04/2020] [Indexed: 01/22/2023] Open
Abstract
Noninvasive diagnostics for Staphylococcus aureus musculoskeletal infections (MSKI) remain challenging. Abs from newly activated, pathogen-specific plasmablasts in human blood, which emerge during an ongoing infection, can be used for diagnosing and tracking treatment response in diabetic foot infections. Using multianalyte immunoassays on medium enriched for newly synthesized Abs (MENSA) from Ab-secreting cells, we assessed anti-S. aureus IgG responses in 101 MSKI patients (63 culture-confirmed S. aureus, 38 S. aureus-negative) and 52 healthy controls. MENSA IgG levels were assessed for their ability to identify the presence and type of S. aureus MSKI using machine learning and multivariate receiver operating characteristic curves. Eleven S. aureus-infected patients were presented with prosthetic joint infections, 15 with fracture-related infections, 5 with native joint septic arthritis, 15 with diabetic foot infections, and 17 with suspected orthopedic infections in the soft tissue. Anti-S. aureus MENSA IgG levels in patients with non-S. aureus infections and healthy controls were 4-fold (***p = 0.0002) and 8-fold (****p < 0.0001) lower, respectively, compared with those with culture-confirmed S. aureus infections. Comparison of MENSA IgG responses among S. aureus culture-positive patients revealed Ags predictive of active MSKI (IsdB, SCIN, Gmd) and Ags predictive of MSKI type (IsdB, IsdH, Amd, Hla). When combined, IsdB, IsdH, Gmd, Amd, SCIN, and Hla were highly discriminatory of S. aureus MSKI (area under the ROC curve = 0.89 [95% confidence interval 0.82-0.93, p < 0.01]). Collectively, these results demonstrate the feasibility of a bioinformatic approach to use a patient's active immune proteome against S. aureus to diagnose challenging MSKI.
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Cole CL, Beck CA, Robinson D, Ye J, Mills B, Gerber SA, Schwarz EM, Linehan D. Dual Energy X-ray Absorptiometry (DEXA) as a longitudinal outcome measure of cancer-related muscle wasting in mice. PLoS One 2020; 15:e0230695. [PMID: 32559188 PMCID: PMC7304564 DOI: 10.1371/journal.pone.0230695] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 05/13/2020] [Indexed: 02/06/2023] Open
Abstract
Introduction Pancreatic ductal adenocarcinoma (PDAC) is notorious for its associated skeletal muscle wasting (SMW) and mortality. Currently, the relationships between PDAC, SMW, and survival are poorly understood. Thus, there is great need for a faithful small animal model with quantitative longitudinal outcome measures that recapitulate clinical PDAC, to define SMW onset and assess progression. Therefore, we aimed to validate dual energy X-ray absorptiometry (DEXA) as a longitudinal measure of lean mass, and demonstrate its utility to quantify SMW in the KCKO murine model of PDAC. Methods In vivo body composition of: 1) untreated mice at 5, 8, 12, 18, and 22 weeks of age (n = 4) and 2) a cohort of mice with (n = 5) and without PDAC (n = 5), was determined via DEXA and lean mass of the lower hind limbs was predicted via a region of interest analysis by two-independent observers. Total body weight was determined. Tibialis anterior (TA) muscles were weighed and processed for histomorphometry immediately post-mortem. Statistical differences between groups were assessed using ANOVA and Student’s t-tests. Linear regression models and correlation analysis were used to measure the association between TA and DEXA mass, and reproducibility of DEXA was quantified via the intraclass correlation coefficient (ICC). Results Lean mass in growing untreated mice determined by DEXA correlated with TA mass (r2 = 0.94; p <0.0001) and body weight (r2 = 0.89; p <0.0001). DEXA measurements were highly reproducible between observers (ICC = 0.95; 95% CI: 0.89–0.98). DEXA and TA mass also correlated in the PDAC cohort (r2 = 0.76; p <0.0001). Significant SMW in tumor-bearing mice was detected within 38 days of implantation, by DEXA, TA mass, and histomorphometry. Conclusions DEXA is a longitudinal outcome measure of lean mass in mice. The KCKO syngeneic model is a bona fide model of PDAC associated SMW that can be quantified with longitudinal DEXA.
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Wu EK, Ambrosini RD, Kottmann RM, Ritchlin CT, Schwarz EM, Rahimi H. Reinterpreting Evidence of Rheumatoid Arthritis-Associated Interstitial Lung Disease to Understand Etiology. Curr Rheumatol Rev 2020; 15:277-289. [PMID: 30652645 DOI: 10.2174/1573397115666190116102451] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Revised: 11/19/2018] [Accepted: 01/05/2019] [Indexed: 02/07/2023]
Abstract
Interstitial Lung Disease (ILD) is a well-known complication of rheumatoid arthritis (RA) which often results in significant morbidity and mortality. It is often diagnosed late in the disease process via descriptive criteria. Multiple subtypes of RA-ILD exist as defined by chest CT and histopathology. In the absence of formal natural history studies and definitive diagnostics, a conventional dogma has emerged that there are two major subtypes of RA-ILD (nonspecific interstitial pneumonia (NSIP) and Usual Interstitial Pneumonia (UIP)). These subtypes are based on clinical experience and correlation studies. However, recent animal model data are incongruous with established paradigms of RA-ILD and beg reassessment of the clinical evidence in order to better understand etiology, pathogenesis, prognosis, and response to therapy. To this end, here we: 1) review the literature on epidemiology, radiology, histopathology and clinical outcomes of the various RAILD subtypes, existing animal models, and current theories on RA-ILD pathogenesis; 2) highlight the major gaps in our knowledge; and 3) propose future research to test an emerging theory of RAILD that posits initial rheumatic lung inflammation in the form of NSIP-like pathology transforms mesenchymal cells to derive chimeric disease, and subsequently develops into frank UIP-like fibrosis in some RA patients. Elucidation of the pathogenesis of RA-ILD is critical for the development of effective interventions for RA-ILD.
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Tomizawa T, Ishikawa M, Bello-Irizarry SN, de Mesy Bentley KL, Ito H, Kates SL, Daiss JL, Beck C, Matsuda S, Schwarz EM, Nishitani K. Biofilm Producing Staphylococcus epidermidis (RP62A Strain) Inhibits Osseous Integration Without Osteolysis and Histopathology in a Murine Septic Implant Model. J Orthop Res 2020; 38:852-860. [PMID: 31692081 PMCID: PMC7071979 DOI: 10.1002/jor.24512] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Accepted: 11/03/2019] [Indexed: 02/04/2023]
Abstract
Despite its presence in orthopaedic infections, Staphylococcus epidermidis's ability to directly induce inflammation and bone destruction is unknown. Thus, we compared a clinical strain of methicillin-resistant biofilm-producing S. epidermidis (RP62A) to a highly virulent and osteolytic strain of methicillin-resistant Staphylococcus aureus (USA300) in an established murine implant-associated osteomyelitis model. Bacterial burden was assessed by colony forming units (CFUs), tissue damage was assessed by histology and micro-computed tomography, biofilm was assessed by scanning electron microscopy (SEM), host gene expression was assessed by quantitative polymerase chain reaction, and osseous integration was assessed via biomechanical push-out test. While CFUs were recovered from RP62A-contaminated implants and surrounding tissues after 14 days, the bacterial burden was significantly less than USA300-infected tibiae (p < 0.001). In addition, RP62A failed to produce any of the gross pathologies induced by USA300 (osteolysis, reactive bone formation, Staphylococcus abscess communities, marrow necrosis, and biofilm). However, fibrous tissue was present at the implant-host interface, and rigorous SEM confirmed the rare presence of cocci on RP62A-contaminated implants. Gene expression studies revealed that IL-1β, IL-6, RANKL, and TLR-2 mRNA levels in RP62A-infected bone were increased versus Sterile controls. Ex vivo push-out testing showed that RP62A-infected implants required significantly less force compared with the Sterile group (7.5 ± 3.4 vs. 17.3 ± 4.1 N; p < 0.001), but required 10-fold greater force than USA300-infected implants (0.7 ± 0.3 N; p < 0.001). Taken together, these findings demonstrate that S. epidermidis is a commensal pathogen whose mechanisms to inhibit osseous integration are limited to minimal biofilm formation on the implant, and low-grade inflammation. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:852-860, 2020.
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O'Keefe RJ, Tuan RS, Lane NE, Awad HA, Barry F, Bunnell BA, Colnot C, Drake MT, Drissi H, Dyment NA, Fortier LA, Guldberg RE, Kandel R, Little DG, Marshall MF, Mao JJ, Nakamura N, Proffen BL, Rodeo SA, Rosen V, Thomopoulos S, Schwarz EM, Serra R. American Society for Bone and Mineral Research-Orthopaedic Research Society Joint Task Force Report on Cell-Based Therapies - Secondary Publication. J Orthop Res 2020; 38:485-502. [PMID: 31994782 DOI: 10.1002/jor.24485] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 06/13/2019] [Indexed: 02/04/2023]
Abstract
Cell-based therapies, defined here as the delivery of cells in vivo to treat disease, have recently gained increasing public attention as a potentially promising approach to restore structure and function to musculoskeletal tissues. Although cell-based therapy has the potential to improve the treatment of disorders of the musculoskeletal system, there is also the possibility of misuse and misrepresentation of the efficacy of such treatments. The medical literature contains anecdotal reports and research studies, along with web-based marketing and patient testimonials supporting cell-based therapy. Both the American Society for Bone and Mineral Research (ASBMR) and the Orthopaedic Research Society (ORS) are committed to ensuring that the potential of cell-based therapies is realized through rigorous, reproducible, and clinically meaningful scientific discovery. The two organizations convened a multidisciplinary and international Task Force composed of physicians, surgeons, and scientists who are recognized experts in the development and use of cell-based therapies. The Task Force was charged with defining the state-of-the art in cell-based therapies and identifying the gaps in knowledge and methodologies that should guide the research agenda. The efforts of this Task Force are designed to provide researchers and clinicians with a better understanding of the current state of the science and research needed to advance the study and use of cell-based therapies for skeletal tissues. The design and implementation of rigorous, thorough protocols will be critical to leveraging these innovative treatments and optimizing clinical and functional patient outcomes. In addition to providing specific recommendations and ethical considerations for preclinical and clinical investigations, this report concludes with an outline to address knowledge gaps in how to determine the cell autonomous and nonautonomous effects of a donor population used for bone regeneration. © 2020 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:485-502, 2020.
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Lee CC, Southgate R, Jiao C, Gersz E, Owen JR, Kates SL, Beck CA, Xie C, Daiss JL, Post V, Moriarty TF, Zeiter S, Schwarz EM, Muthukrishnan G. Deriving a dose and regimen for anti-glucosaminidase antibody passive-immunisation for patients with Staphylococcus aureus osteomyelitis. Eur Cell Mater 2020; 39:96-107. [PMID: 32003439 PMCID: PMC7236896 DOI: 10.22203/ecm.v039a06] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Staphylococcus aureus (S. aureus) osteomyelitis remains a major clinical problem. Anti-glucosaminidase (Gmd) antibodies (1C11) are efficacious in prophylactic and therapeutic murine models. Feasibility, safety and pharmacokinetics of 1C11 passive immunisation in sheep and endogenous anti-Gmd levels were quantified in osteomyelitis patients. 3 sheep received a 500 mg intravenous (i.v.) bolus of 1C11 and its levels in sera were determined by enzyme-linked immunosorbent assay (ELISA) over 52 d. A humanised anti-Gmd monoclonal antibody, made by grafting the antigen-binding fragment (Fab) portion of 1C11 onto the fragment crystallisable region (Fc) of human IgG1, was used to make a standard curve of mean fluorescent intensity versus concentration of anti-Gmd. Anti-Gmd serum levels were determined in 297 patients with culture-confirmed S. aureus osteomyelitis and 40 healthy controls. No complications or adverse events were associated with the sheep 1C11 i.v. infusion and the estimated circulating half-life of 1C11 was 23.7 d. Endogenous anti-Gmd antibody levels in sera of osteomyelitis patients ranged from < 1 ng/mL to 300 µg/mL, with a mean concentration of 21.7 µg/mL. The estimated circulating half-life of endogenous anti-Gmd antibodies in sera of 12 patients with cured osteomyelitis was 120.4 d. A clinically relevant administration of anti-Gmd (500 mg i.v. = 7 mg/kg/70 kg human) was safe in sheep. This dose was 8 times more than the endogenous anti-Gmd levels observed in osteomyelitis patients and was predicted to have a half-life of > 3 weeks. Anti-Gmd passive immunisation has potential to prevent and treat S. aureus osteomyelitis. Further clinical development is warranted.
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O'Keefe RJ, Tuan RS, Lane NE, Awad HA, Barry F, Bunnell BA, Colnot C, Drake MT, Drissi H, Dyment NA, Fortier LA, Guldberg RE, Kandel R, Little DG, Marshall MF, Mao JJ, Nakamura N, Proffen BL, Rodeo SA, Rosen V, Thomopoulos S, Schwarz EM, Serra R. American Society for Bone and Mineral Research-Orthopaedic Research Society Joint Task Force Report on Cell-Based Therapies. J Bone Miner Res 2020; 35:3-17. [PMID: 31545883 DOI: 10.1002/jbmr.3839] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 05/28/2019] [Accepted: 06/13/2019] [Indexed: 01/01/2023]
Abstract
Cell-based therapies, defined here as the delivery of cells in vivo to treat disease, have recently gained increasing public attention as a potentially promising approach to restore structure and function to musculoskeletal tissues. Although cell-based therapy has the potential to improve the treatment of disorders of the musculoskeletal system, there is also the possibility of misuse and misrepresentation of the efficacy of such treatments. The medical literature contains anecdotal reports and research studies, along with web-based marketing and patient testimonials supporting cell-based therapy. Both the American Society for Bone and Mineral Research (ASBMR) and the Orthopaedic Research Society (ORS) are committed to ensuring that the potential of cell-based therapies is realized through rigorous, reproducible, and clinically meaningful scientific discovery. The two organizations convened a multidisciplinary and international Task Force composed of physicians, surgeons, and scientists who are recognized experts in the development and use of cell-based therapies. The Task Force was charged with defining the state-of-the art in cell-based therapies and identifying the gaps in knowledge and methodologies that should guide the research agenda. The efforts of this Task Force are designed to provide researchers and clinicians with a better understanding of the current state of the science and research needed to advance the study and use of cell-based therapies for skeletal tissues. The design and implementation of rigorous, thorough protocols will be critical to leveraging these innovative treatments and optimizing clinical and functional patient outcomes. In addition to providing specific recommendations and ethical considerations for preclinical and clinical investigations, this report concludes with an outline to address knowledge gaps in how to determine the cell autonomous and nonautonomous effects of a donor population used for bone regeneration. © 2019 American Society for Bone and Mineral Research.
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Cole CL, Vasalos K, Nicandri G, Apt C, Osterling E, Ferrara Z, Maloney MD, Schwarz EM, Rizzone K. Use of PROMIS and Functional Movement System (FMS) Testing to Evaluate the Effects of Athletic Performance and Injury Prevention Training in Female High School Athletes. ORTHOPEDICS AND SPORTS MEDICINE : OPEN ACCESS JOURNAL 2019; 3:255-258. [PMID: 32039407 PMCID: PMC7007986 DOI: 10.32474/osmoaj.2019.03.000160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Two major health concerns with female high school athletes are: 1) psychosocial wellness, and 2) sports-related injuries. It is also known that these health concerns are much greater for minority students who attend high school in economically depressed cities. While it has been well-established that exercise is an effective intervention for these health concerns, there are no established outcome measures to quantitatively assess athletic performance and injury prevention training interventions in this population. Previously, we have demonstrated the utility of Patient-Reported Outcomes Measurement Information System (PROMIS) as a robust outcome measure following ACL reconstruction. Functional Movement Screening (FMS) has been used as a tool to determine injury risk in female collegiate athletes. Since these tools are broadly available, we completed a research study of urban underrepresented minority and suburban female high school athletes, to assess the feasibility and utility of these tools to measure changes in this population during 10-weeks of athletic training. No adverse events of the training or study were reported. A Kaplan-Meier assessment of the data revealed that there was high student retention throughout the 10 weeks. In addition, we found no difference in weekly attendance between the students that completed the intervention vs. the dropouts (while they were in the program), indicating that the students were highly motivated to attend when possible. While no significant differences were found for fatigue and physical function, the intervention significantly improved anxiety, peer relationships, pain interference, and trended towards significance for depression (p<0.05). In terms of physical performance, bench press, combined Pro Agility, and total FMS were all significantly improved (p<0.05). Surprisingly, there were 10 students (67%) in peril of sports- related injury (FM˂14) at the start of the intervention, and all but 1 (90%) eliminated this serious risk factor. Collectively, these results demonstrate the feasibility of PROMIS and FMS outcomes to assess the efficacy of physical training interventions, in underrepresented minority female high school students, which warrants investigation in a formal prospective study.
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Muthukrishnan G, Masters EA, Daiss JL, Schwarz EM. Mechanisms of Immune Evasion and Bone Tissue Colonization That Make Staphylococcus aureus the Primary Pathogen in Osteomyelitis. Curr Osteoporos Rep 2019; 17:395-404. [PMID: 31721069 PMCID: PMC7344867 DOI: 10.1007/s11914-019-00548-4] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
PURPOSE OF REVIEW Staphylococcus aureus is the primary pathogen responsible for osteomyelitis, which remains a major healthcare burden. To understand its dominance, here we review the unique pathogenic mechanisms utilized by S. aureus that enable it to cause incurable osteomyelitis. RECENT FINDINGS Using an arsenal of toxins and virulence proteins, S. aureus kills and usurps immune cells during infection, to produce non-neutralizing pathogenic antibodies that thwart adaptive immunity. S. aureus also has specific mechanisms for distinct biofilm formation on implants, necrotic bone tissue, bone marrow, and within the osteocyte lacuno-canicular networks (OLCN) of live bone. In vitro studies have also demonstrated potential for intracellular colonization of osteocytes, osteoblasts, and osteoclasts. S. aureus has evolved a multitude of virulence mechanisms to achieve life-long infection of the bone, most notably colonization of OLCN. Targeting S. aureus proteins involved in these pathways could provide new targets for antibiotics and immunotherapies.
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Wu EK, Henkes ZI, McGowan B, Bell RD, Velez MJ, Livingstone AM, Ritchlin CT, Schwarz EM, Rahimi H. TNF-Induced Interstitial Lung Disease in a Murine Arthritis Model: Accumulation of Activated Monocytes, Conventional Dendritic Cells, and CD21 +/CD23 - B Cell Follicles Is Prevented with Anti-TNF Therapy. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2019; 203:2837-2849. [PMID: 31659014 PMCID: PMC6989047 DOI: 10.4049/jimmunol.1900473] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 09/29/2019] [Indexed: 12/29/2022]
Abstract
Interstitial lung disease (ILD) is a well-known extra-articular manifestation of rheumatoid arthritis (RA). RA-associated ILD (RA-ILD) exists on a wide spectrum, with variable levels of inflammatory and fibrotic activity, although all subtypes are regarded as irreversible pathologic conditions. In both articular and pulmonary manifestations, TNF is a significant pathogenic factor. Whereas anti-TNF therapy alleviates joint pathologic conditions, it exacerbates fibrotic RA-ILD. The TNF-transgenic (TNF-Tg) murine model of RA develops both inflammatory arthritis and an ILD that mimics a cellular nonspecific interstitial pneumonia pattern dominated by an interstitial accumulation of inflammatory cells with minimal-to-absent fibrosis. Given the model's potential to elucidate the genesis of inflammatory RA-ILD, we aim to achieve the following: 1) characterize the cellular accumulations in TNF-Tg lungs, and 2) assess the reversibility of inflammatory ILD following anti-TNF therapy known to resolve TNF-Tg inflammatory arthritis. TNF-Tg mice with established disease were randomized to anti-TNF or placebo therapy and evaluated with imaging, histology, and flow cytometric analyses, together with wild-type controls. Flow cytometry of TNF-Tg versus wild-type lungs revealed significant increases in activated monocytes, conventional dendritic cells, and CD21+/CD23- B cells that are phenotypically distinct from the B cells in inflamed nodes, which are known to accumulate in joint-draining lymph nodes. In contrast to human RA-ILD, anti-TNF treatment significantly alleviated both joint and lung inflammation. These results identify a potential role for activated monocytes, conventional dendritic cells, and CD21+/CD23- B cells in the genesis of RA-ILD, which exist in a previously unknown, reversible, prefibrotic stage of the disease.
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de Mesy Bentley KL, MacDonald A, Schwarz EM, Oh I. Chronic Osteomyelitis with Staphylococcus aureus Deformation in Submicron Canaliculi of Osteocytes: A Case Report. JBJS Case Connect 2019; 8:e8. [PMID: 29443819 DOI: 10.2106/jbjs.cc.17.00154] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
CASE A patient presenting with an infected diabetic foot ulcer and Staphylococcus aureus chronic osteomyelitis was studied to validate the clinical importance of bacterial colonization of osteocytic-canalicular networks, as we recently reported in a mouse model. We utilized transmission electron microscopy to describe the deformation of S. aureus, from round cocci to rod-shaped bacteria, in the submicron osteocytic-canalicular networks of amputated bone tissue. CONCLUSION To our knowledge, this is the first evidence of S. aureus deformation and invasion of the osteocytic-canalicular system in human bone, which supports a new mechanism of persistence in the pathogenesis of chronic osteomyelitis.
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Bell RD, Slattery PN, Wu EK, Xing L, Ritchlin CT, Schwarz EM. iNOS dependent and independent phases of lymph node expansion in mice with TNF-induced inflammatory-erosive arthritis. Arthritis Res Ther 2019; 21:240. [PMID: 31727153 PMCID: PMC6854801 DOI: 10.1186/s13075-019-2039-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 10/23/2019] [Indexed: 01/15/2023] Open
Abstract
Introduction A pivotal effect of lymphatic vessel (LV) function in joint homeostasis was identified in the tumor necrosis factor-transgenic (TNF-Tg) mouse model of rheumatoid arthritis (RA). Specifically, loss of LV contractions is associated with progressive synovitis and erosions. Furthermore, draining lymph node expansion is a biomarker of arthritic progression, and both macrophages and lymphatic endothelial cells express inducible nitric oxide synthase (iNOS), which disrupts LV contraction and transport of immune cells to the draining lymph nodes. Therefore, to directly assess these relationships, we tested the hypothesis that TNF-Tg mice with global genetic ablation of iNOS (iNOS−/−) will show delayed draining lymph node expansion, maintained LV contractions, and decreased synovitis and erosions. Method iNOS−/−× TNF-Tg female and male mice, and control littermates (iNOS−/−, TNF-Tg, and WT), were examined with (1) ultrasound to determine popliteal lymph node (PLN) volume and (2) near-infrared imaging (NIR) to assess popliteal LV contraction frequency, and differences between genotypes were assessed at 3, 4, 5, and 6 months of age. Knees and PLN were harvested at 4 months in females and 6 months in males, to assess synovitis, bone erosions, and cellular accumulation in PLN sinuses via histology. Results Initially, an increase in PLN volume was observed for both female and male iNOS−/−× TNF-Tg and TNF-Tg compared to their WT and iNOS−/− counterparts at 2 and 3 months, respectively. Subsequently, TNF-Tg PLNs continue to increase in volume, while iNOS−/−× TNF-Tg did not increase in volume from the initial timepoints. WT and iNOS−/− PLN volume was unchanged throughout the experiment. LV contraction frequency was increased at 4 months in females and 5 months in males, in the iNOS−/−× TNF-Tg mice compared to the TNF-Tg. Synovitis and erosions were moderately reduced in iNOS−/−× TNF-Tg versus TNF-Tg knees in females, while no differences in knee pathology were observed in males. Conclusions Genetic iNOS ablation maintains draining lymph node volume and LV function during TNF-induced inflammatory arthritis and is associated with moderately decreased joint inflammation and damage.
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Liang Q, Zhang L, Wood RW, Ji RC, Boyce BF, Schwarz EM, Wang Y, Xing L. Avian Reticuloendotheliosis Viral Oncogene Related B Regulates Lymphatic Endothelial Cells during Vessel Maturation and Is Required for Lymphatic Vessel Function in Adult Mice. THE AMERICAN JOURNAL OF PATHOLOGY 2019; 189:2516-2530. [PMID: 31539516 DOI: 10.1016/j.ajpath.2019.08.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 08/05/2019] [Accepted: 08/22/2019] [Indexed: 12/16/2022]
Abstract
NF-κB signals through canonical transcription factor p65 (RelA)/p50 and noncanonical avian reticuloendotheliosis viral oncogene related B (RelB)/p52 pathways. The RelA/p50 is involved in basal and inflammatory lymphangiogenesis. However, the role of RelB/p52 in lymphatic vessel biology is unknown. Herein, we investigated changes in lymphatic vessels (LVs) in mice deficient in noncanonical NF-κB signaling and the function of RelB in lymphatic endothelial cells (LECs). LVs were examined in Relb-/-, p52-/-, or control mice, and the gene expression profiles in LECs with RelB knockdown. Relb-/-, but not p52-/-, mice exhibited multiple LV abnormalities. They include the following: i) increased capillary vessel diameter, ii) reduced smooth muscle cell (SMC) coverage of mature vessels, iii) leakage, and iv) loss of active and passive lymphatic flow. Relb-/- mature LVs had thinner vessel walls, more apoptotic LECs and SMCs, and fewer LEC junctions. RelB knockdown LECs had decreased growth, survival, and adhesion, and dysregulated signaling pathways involving these cellular events. These results suggest that Relb-/- mice have abnormal LVs, mainly in mature vessels with reduced SMC coverage, leakage, and loss of contractions. RelB knockdown in LECs leads to reduced growth, survival, and adhesion. RelB plays a vital role in LEC-mediated LV maturation and function.
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