Resident Synovial Macrophages in Synovial Fluid: Implications for Immunoregulation in Infectious and Inflammatory Arthritis.

Objectives: Resident synovial macrophages (RSM) provide immune sequestration of the joint space and are likely involved in initiation and perpetuation of the joint-specific immune response. We sought to identify RSM in synovial fluid (SF) and demonstrate migratory ability, in additional to functional changes that may perpetuate a chronic inflammatory response within joint spaces. Methods: We recruited human patients presenting with undifferentiated arthritis in multiple clinical settings. We used flow cytometry to identify mononuclear cells in peripheral blood and SF. We used a novel transwell migration assay with human ex-vivo synovium obtained intra-operatively to validate flow cytometry findings. We used single cell RNA-sequencing (scRNA-seq) to further identify macrophage/monocyte subsets. ELISA was used to evaluate the bone-resorption potential of SF. Results: We were able to identify a rare population of CD14dim, OPG+, ZO-1+ cells consistent with RSM in SF via flow cytometry. These cells were relatively enriched in the SF during infectious processes, but absolutely decreased compared to healthy controls. Similar putative RSM were identified using ex vivo migration assays when MCP-1 and LPS were used as migratory stimulus. scRNA-seq revealed a population consistent with RSM transcriptionally related to CD56+ cytotoxic dendritic cells and IDO+ M2 macrophages. Conclusion: We identified a rare cell population consistent with RSM, indicating these cells are likely migratory and able to initiate or coordinate both acute (septic) or chronic (autoimmune or inflammatory) arthritis. RSM analysis via scRNA-seq indicated these cells are M2 skewed, capable of antigen presentation, and have consistent functions in both septic and inflammatory arthritis.

Plasma microrna quantification protocol.

MicroRNAs (miRNAs) are small non-coding RNA molecules that regulate translation and are involved in many pathological processes. They have emerged as promising biomarkers for diagnosis of conditions such as aortic aneurysm disease. Quantifying miRNAs in plasma is uniquely challenging because of the lack of standardized reproducible protocols. To facilitate the independent verification of conclusions, it is necessary to provide a thorough disclosure of all pertinent experimental details. In this technical note, we present a comprehensive protocol for quantifying plasma miRNAs using droplet digital PCR. We detail the entire workflow, including blood collection, plasma processing, cryo-storage, miRNA isolation, reverse transcription, droplet generation, PCR amplification, fluorescence reading, and data analysis. We offer comprehensive guidance regarding optimization, assay conditions, expected results, and insight into the troubleshooting of common issues. The stepwise normalization and detailed methodological guide enhance reproducibility. Moreover, multiple portions of this protocol may be automated. The data provided in this technical note is demonstrative of the values typically obtained when following its steps. To facilitate standardization in data reporting, we include a table of expected aortic aneurysm-related miRNA levels in healthy human plasma. This versatile protocol can be easily adapted to quantify most circulating miRNAs in plasma, making it a valuable resource for diagnostic development.

miR-133a Replacement Attenuates Thoracic Aortic Aneurysm in Mice.

Background Thoracic aortic aneurysms (TAAs) occur because of abnormal remodeling of aortic extracellular matrix and are accompanied by the emergence of proteolytically active myofibroblasts. The microRNA miR-133a regulates cellular phenotypes and is reduced in clinical TAA specimens. This study tested the hypothesis that miR-133a modulates aortic fibroblast phenotype, and overexpression by lentivirus attenuates the development of TAA in a murine model. Methods and Results TAA was induced in mice. Copy number of miR-133a was reduced in TAA tissue and linear regression analysis confirmed an inverse correlation between aortic diameter and miR-133a. Analyses of phenotypic markers revealed an mRNA expression profile consistent with myofibroblasts in TAA tissue. Fibroblasts were isolated from the thoracic aortae of mice with/without TAA. When compared with controls, miR-133a was reduced, migration was increased, adhesion was reduced, and the ability to contract a collagen disk was increased. Overexpression/knockdown of miR-133a controlled these phenotypes. After TAA induction in mice, a single tail-vein injection of either miR-133a overexpression or scrambled sequence (control) lentivirus was performed. Overexpression of miR-133a attenuated TAA development. The pro-protein convertase furin was confirmed to be a target of miR-133a by luciferase reporter assay. Furin was elevated in this murine model of TAA and repressed by miR-133a replacement in vivo resulting in reduced proteolytic activation. Conclusions miR-133a regulates aortic fibroblast phenotype and over-expression prevented the development of TAA in a murine model. These findings suggest that stable alterations in aortic fibroblasts are associated with development of TAA and regulation by miR-133a may lead to a novel therapeutic strategy.

Use of Blood Flow Restriction Training for Postoperative Rehabilitation.

Blood flow restriction (BFR) training is commonly used to induce muscle hypertrophy and strength and is gaining popularity as a modality for treatment of musculoskeletal conditions and postoperative rehabilitation. This article reviews the current literature on BFR as a rehabilitative tool, identifies gaps in the literature, and reports the authors experience using BFR in the postoperative environment.

Infectious Disease in Contact Sports.

CONTEXT:: Infections are common in contact sports. This review aims to describe the epidemiology, presenting signs and symptoms, treatment guidelines, and regulations for several common infections seen in contact sport athletes. The conditions discussed include bacterial skin infections, herpes simplex virus, molluscum contagiosum, common warts, tinea, scabies, head lice, conjunctivitis, human immunodeficiency virus, hepatitis C virus, and vaccine-preventable illnesses. EVIDENCE ACQUISITION:: Searches were performed across PubMed and MEDLINE research databases. In addition, general internet search engine results and reviews of reference lists of relevant papers were used to identify additional sources of evidence. STUDY DESIGN:: Clinical review. LEVEL OF EVIDENCE:: Level 4. RESULTS:: The most common infections seen in contact sport athletes include bacterial skin infections, herpes simplex virus, molluscum contagiosum, common warts, tinea, scabies, head lice, conjunctivitis, and vaccine-preventable illnesses. Other infections, including human immunodeficiency virus and hepatitis C, are uncommon but potentially life threatening. CONCLUSION:: Infections are common in contact sport athletes. The provider who cares for these athletes should be aware of the most common infections and their appropriate management. Early diagnosis and appropriate clinical management are important for treating the infected athlete, minimizing risk of transmission, minimizing time lost from competition, and preventing large outbreaks.

Using sideline concussion tests in the emergency department.

PURPOSE: Traumatic brain injury (TBI) is a significant cause of death and disability in the United States. Many patients with TBI are initially treated in the emergency department (ED), but there is no evidence-based method of detecting or grading TBI in patients who have normal structural neuroimaging. This study aims to evaluate the validity of two common sideline concussion tests. The Concussion Symptom Severity Score (CSSS) and modified Balance Error Scoring System (mBESS) tests are well-validated sideline tests for concussion, but have not been validated in the setting of non-sport-related concussion, in settings other than the sideline or athletic training room or in moderate or severe TBI. PATIENTS AND METHODS: One hundred forty-eight subjects who had sustained a TBI within the previous 72 hours and 53 healthy control subjects were enrolled. CSSS and mBESS were administered. Clinical outcomes were followed up prospectively. RESULTS: The CSSS was collected in 147 TBI subjects but only 51 TBI subjects were able to complete the mBESS. The CSSS was collected for all 53 control subjects, and the mBESS was completed for 51 control subjects. The mean CSSS for TBI and control subjects was 32.25 and 2.70, respectively (P < 0.001). The average mBESS for TBI and control subjects was 7.43 and 7.20, respectively (P = 0.82). CSSS greater than 5.17 was 93.43% sensitive and 69.84% specific for TBI. CONCLUSION: The mBESS is poorly tolerated and, among those who can complete the test, not sensitive to TBI in the ED. The CSSS is both sensitive to TBI and well tolerated.

Youth Football Injuries: A Prospective Cohort.

BACKGROUND: There are approximately 2.8 million youth football players between the ages of 7 and 14 years in the United States. Rates of injury in this population are poorly described. Recent studies have reported injury rates between 2.3% and 30.4% per season and between 8.5 and 43 per 1000 exposures. HYPOTHESIS: Youth flag football has a lower injury rate than youth tackle football. The concussion rates in flag football are lower than in tackle football. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Three large youth (grades 2-7) football leagues with a total of 3794 players were enrolled. Research personnel partnered with the leagues to provide electronic attendance and injury reporting systems. Researchers had access to deidentified player data and injury information. Injury rates for both the tackle and flag leagues were calculated and compared using Poisson regression with a log link. The probability an injury was severe and an injury resulted in a concussion were modeled using logistic regression. For these 2 responses, best subset model selection was performed, and the model with the minimum Akaike information criterion value was chosen as best. Kaplan-Meier curves were examined to compare time loss due to injury for various subgroups of the population. Finally, time loss was modeled using Cox proportional hazards regression models. RESULTS: A total of 46,416 exposures and 128 injuries were reported. The mean age at injury was 10.64 years. The hazard ratio for tackle football (compared with flag football) was 0.45 (95% CI, 0.25-0.80; P = .0065). The rate of severe injuries per exposure for tackle football was 1.1 (95% CI, 0.33-3.4; P = .93) times that of the flag league. The rate for concussions in tackle football per exposure was 0.51 (95% CI, 0.16-1.7; P = .27) times that of the flag league. CONCLUSION: Injury is more likely to occur in youth flag football than in youth tackle football. Severe injuries and concussions were not significantly different between leagues. Concussion was more likely to occur during games than during practice. Players in the sixth or seventh grade were more likely to suffer a concussion than were younger players.

Weight Management Counseling for Wrestling Athletes.

Helping a wrestler manage body weight can be a daunting process for a pediatric health care provider. Each high school wrestling program has been mandated by the National Federation of State High School Associations to determine an appropriate weight classification for each individual wrestler. This article discusses how an appropriate weight class is determined, the methods for ascertaining a person's hydration status and body density, and the importance of a fully hydrated and normally nourished state that will allow for optimal athletic performance for a wrestler.

Lactate: Friend or Foe.

Lactic acid has played an important role in the traditional theory of muscle fatigue and limitation of endurance exercise performance. It has been called a waste product of anaerobic metabolism and has been believed to be responsible for the uncomfortable "burn" of intense exercise and directly responsible for the metabolic acidosis of exercise, leading to decreased muscle contractility and ultimately cessation of exercise. Although this premise has been commonly taught, it is not supported by the scientific literature and has led to a great deal of confusion among the sports medicine and exercise science communities. This review will provide the sports medicine clinician with an understanding of contemporary lactate theories, including lactate's role in energy production, its contributions to metabolic acidosis, and its function as an energy substrate for a variety of tissues. Lactate threshold concepts will also be discussed, including a practical approach to understanding prediction of performance and monitoring of training progress based on these parameters.

Basic recovery aids: what's the evidence?

This review summarizes the evidence base for using compression, massage, caloric replacement, cold, and heat as exercise recovery aids in sport.

Utilization of a text-messaging robot to assess intraday variation in concussion symptom severity scores.

OBJECTIVE: To determine the amount of within-day variation of Concussion Symptom Severity Scores (CSSSs) in athletes with a clinically diagnosed concussion. DESIGN: This prospective cohort study used a text-messaging robot to survey concussed athletes using the CSSS 5-times daily while they remained symptomatic. SETTING: Academic sports concussion clinic at a large tertiary care medical center. PARTICIPANTS: Fourteen 14- to 22-year-old athletes with clinically diagnosed concussions were enrolled. All were injured in sport, still in season, English speaking, and used a cellular telephone to text message on a regular basis. ASSESSMENT OF RISK FACTORS: This study did not collect any demographic or other information about the subjects. The only data collected were the individual responses to the questions in the Post Concussion Symptom Score (PCSS). The only aim of this study was to evaluate the variability in responses to the CSSS, which is calculated from the PCSS. MAIN OUTCOME MEASUREMENTS: The primary outcome measure was a repeatability coefficient from a random-effects model. Concussion Symptom Severity Score, mean daily CSSS, and standard deviation of CSSS differences from the mean were also calculated. RESULTS: Mean follow-up was 23.9 days. A total of 24 180 text messages were received from subjects. Eight hundred four complete surveys were analyzed. Repeatability coefficient was ±23.1. CONCLUSIONS: When surveyed frequently by a text-messaging robot, concussed athletes report poorly repeatable Sport Concussion Assessment Tool 2 (SCAT2) Symptom Severity Scores. CLINICAL RELEVANCE: The SCAT2 Symptom Severity Score may be an invalid method of tracking concussion severity and resolution over time.

Pilot study of adolescent attitudes regarding ski or snowboard helmet use.

INTRODUCTION: The number of head injuries from skiing and snowboarding accidents is increasing among adolescents. Ski helmets reduce the risk of head injury. This study explored adolescent attitudes regarding helmet use. METHODS: This pilot study included 11 high school students participating in a 1-hour focus group. RESULTS: There was agreement that head injury is unlikely compared to other injuries, and use of helmets is determined by level of difficulty of the activity. Peer use makes personal use more acceptable and likely. Helmet cost is a minor barrier. Personal experience with a head injury increases use. Mandatory helmet use was viewed positively by most of the subjects. CONCLUSIONS: This pilot study suggests that, similar to bicycle helmet promotion programs, ski and snowboard helmet campaigns should focus on delivering a positive image of helmet use and peer acceptance.