ABCD of IA: A multi-scale agent-based model of T cell activation in inflammatory arthritis.

Biomaterial-based agents have been demonstrated to regulate the function of immune cells in models of autoimmunity. However, the complexity of the kinetics of immune cell activation can present a challenge in optimizing the dose and frequency of administration. Here, we report a model of autoreactive T cell activation, which are key drivers in autoimmune inflammatory joint disease. The model is termed a multi-scale Agent-Based, Cell-Driven model of Inflammatory Arthritis (ABCD of IA). Using kinetic rate equations and statistical theory, ABCD of IA simulated the activation and presentation of autoantigens by dendritic cells, interactions with cognate T cells and subsequent T cell proliferation in the lymph node and IA-affected joints. The results, validated with in vivo data from the T cell driven SKG mouse model, showed that T cell proliferation strongly correlated with the T cell receptor (TCR) affinity distribution (TCR-ad), with a clear transition state from homeostasis to an inflammatory state. T cell proliferation was strongly dependent on the amount of antigen in antigenic stimulus event (ASE) at low concentrations. On the other hand, inflammation driven by Th17-inducing cytokine mediated T cell phenotype commitment was influenced by the initial level of Th17-inducing cytokines independent of the amount of arthritogenic antigen. The introduction of inhibitory artificial antigen presenting cells (iaAPCs), which locally suppress T cell activation, reduced T cell proliferation in a dose-dependent manner. The findings in this work set up a framework based on theory and modeling to simulate personalized therapeutic strategies in IA.

Immunomodulatory Nanoparticles for Modulating Arthritis Flares.

Disease-modifying drugs have improved the treatment for autoimmune joint disorders, such as rheumatoid arthritis, but inflammatory flares are a common experience. This work reports the development and application of flare-modulating poly(lactic-co-glycolic acid)-poly(ethylene glycol)-maleimide (PLGA-PEG-MAL)-based nanoparticles conjugated with joint-relevant peptide antigens, aggrecan70-84 and type 2 bovine collagen256-270. Peptide-conjugated PLGA-PEG-MAL nanoparticles encapsulated calcitriol, which acted as an immunoregulatory agent, and were termed calcitriol-loaded nanoparticles (CLNP). CLNP had a ∼200 nm hydrodynamic diameter with a low polydispersity index. In vitro, CLNP induced phenotypic changes in bone marrow derived dendritic cells (DC), reducing the expression of costimulatory and major histocompatibility complex class II molecules, and proinflammatory cytokines. Bulk RNA sequencing of DC showed that CLNP enhanced expression of Ctla4, a gene associated with downregulation of immune responses. In vivo, CLNP accumulated in the proximal lymph nodes after intramuscular injection. Administration of CLNP was not associated with changes in peripheral blood cell numbers or cytokine levels. In the collagen-induced arthritis and SKG mouse models of autoimmune joint disorders, CLNP reduced clinical scores, prevented bone erosion, and preserved cartilage proteoglycan, as assessed by high-resolution microcomputed tomography and histomorphometry analysis. The disease protective effects were associated with increased CTLA-4 expression in joint-localized DC and CD4+ T cells but without generalized suppression of T cell-dependent immune response. The results support the potential of CLNP as modulators of disease flares in autoimmune arthropathies.

Biodegradable scaffolds for enhancing vaccine delivery.

Sustained release of vaccine components is a potential method to boost efficacy compared with traditional bolus injection. Here, we show that a biodegradable hyaluronic acid (HA)-scaffold, termed HA cryogel, mediates sustained antigen and adjuvant release in vivo leading to a durable immune response. Delivery from subcutaneously injected HA cryogels was assessed and a formulation which enhanced the immune response while minimizing the inflammation associated with the foreign body response was identified, termed CpG-OVA-HAC2. Dose escalation studies with CpG-OVA-HAC2 demonstrated that both the antibody and T cell responses were dose-dependent and influenced by the competency of neutrophils to perform oxidative burst. In immunodeficient post-hematopoietic stem cell transplanted mice, immunization with CpG-OVA-HAC2 elicited a strong antibody response, three orders of magnitude higher than dose-matched bolus injection. In a melanoma model, CpG-OVA-HAC2 induced dose-responsive prophylactic protection, slowing the tumor growth rate and enhancing overall survival. Upon rechallenge, none of the mice developed new tumors suggesting the development of robust immunological memory and long-lasting protection against repeat infections. CpG-OVA-HAC2 also enhanced survival in mice with established tumors. The results from this work support the potential for CpG-OVA-HAC2 to enhance vaccine delivery.

Implementation of a pediatric bed prioritization process in a rural Minnesota community-based hospital.

Inpatient capacity constraints have been a pervasive challenge for hospitals throughout the COVID-19 pandemic. The Mayo Clinic Health System - Southwest Minnesota region primarily serves patients in rural southwestern Minnesota and part of Iowa and consists of 1 postacute care hospital, 1 tertiary care medical center, and 3 critical access hospitals. The main hub, Mayo Clinic Health System in Mankato, Minnesota, has a pediatric unit with dedicated pediatric hospitalists. To address the growing demand for adult inpatient beds at the height of the pandemic, the pediatric unit was opened to allow adult patients to be admitted when necessary. For several months, adult inpatient capacity exceeded 90%, which decreased the number of available pediatric (vs adult) beds throughout Minnesota, particularly in rural communities. Data for the health system showed that children were most affected because transfers to the next available hospitals for pediatric cases were 55 miles away or more. To address this gap, the hospital team successfully trialed a pediatric bed prioritization guideline that reduced pediatric transfers by 40%. This was accomplished by prioritizing the last remaining inpatient bed on the pediatric unit for pediatric patients only. This process not only reduced pediatric transfers but also increased unique patient admissions because of an average lower length of stay for pediatric patients compared with adult patients.

Immunomodulatory Microparticles Epigenetically Modulate T Cells and Systemically Ameliorate Autoimmune Arthritis.

Disease modifying antirheumatic drugs (DMARDs) have improved the prognosis of autoimmune inflammatory arthritides but a large fraction of patients display partial or nonresponsiveness to front-line DMARDs. Here, an immunoregulatory approach based on sustained joint-localized release of all-trans retinoic acid (ATRA), which modulates local immune activation and enhances disease-protective T cells and leads to systemic disease control is reported. ATRA imprints a unique chromatin landscape in T cells, which is associated with an enhancement in the differentiation of naïve T cells into anti-inflammatory regulatory T cells (Treg ) and suppression of Treg destabilization. Sustained release poly-(lactic-co-glycolic) acid (PLGA)-based biodegradable microparticles encapsulating ATRA (PLGA-ATRA MP) are retained in arthritic mouse joints after intra-articular (IA) injection. IA PLGA-ATRA MP enhance migratory Treg which in turn reduce inflammation and modify disease in injected and uninjected joints, a phenotype that is also reproduced by IA injection of Treg . PLGA-ATRA MP reduce proteoglycan loss and bone erosions in the SKG and collagen-induced arthritis mouse models of autoimmune arthritis. Strikingly, systemic disease modulation by PLGA-ATRA MP is not associated with generalized immune suppression. PLGA-ATRA MP have the potential to be developed as a disease modifying agent for autoimmune arthritis.

Immune-responsive biodegradable scaffolds for enhancing neutrophil regeneration.

Neutrophils are essential effector cells for mediating rapid host defense and their insufficiency arising from therapy-induced side-effects, termed neutropenia, can lead to immunodeficiency-associated complications. In autologous hematopoietic stem cell transplantation (HSCT), neutropenia is a complication that limits therapeutic efficacy. Here, we report the development and in vivo evaluation of an injectable, biodegradable hyaluronic acid (HA)-based scaffold, termed HA cryogel, with myeloid responsive degradation behavior. In mouse models of immune deficiency, we show that the infiltration of functional myeloid-lineage cells, specifically neutrophils, is essential to mediate HA cryogel degradation. Post-HSCT neutropenia in recipient mice delayed degradation of HA cryogels by up to 3 weeks. We harnessed the neutrophil-responsive degradation to sustain the release of granulocyte colony stimulating factor (G-CSF) from HA cryogels. Sustained release of G-CSF from HA cryogels enhanced post-HSCT neutrophil recovery, comparable to pegylated G-CSF, which, in turn, accelerated cryogel degradation. HA cryogels are a potential approach for enhancing neutrophils and concurrently assessing immune recovery in neutropenic hosts.

Short-chain fatty acid-mediated epigenetic modulation of inflammatory T cells in vitro.

Short-chain fatty acids (SCFAs) are major metabolic products of indigestible polysaccharides in the gut and mediate the function of immune cells to facilitate homeostasis. The immunomodulatory effect of SCFAs has been attributed, at least in part, to the epigenetic modulation of immune cells through the inhibition the nucleus-resident enzyme histone deacetylase (HDAC). Among the downstream effects, SCFAs enhance regulatory T cells (Treg) over inflammatory T helper (Th) cells, including Th17 cells, which can be pathogenic. Here, we characterize the potential of two common SCFAs-butyrate and pentanoate-in modulating differentiation of T cells in vitro. We show that butyrate but not pentanoate exerts a concentration-dependent effect on Treg and Th17 differentiation. Increasing the concentration of butyrate suppresses the Th17-associated RORγtt and IL-17 and increases the expression of Treg-associated FoxP3. To effectively deliver butyrate, encapsulation of butyrate in a liposomal carrier, termed BLIPs, reduced cytotoxicity while maintaining the immunomodulatory effect on T cells. Consistent with these results, butyrate and BLIPs inhibit HDAC and promote a unique chromatin landscape in T cells under conditions that otherwise promote conversion into a pro-inflammatory phenotype. Motif enrichment analysis revealed that butyrate and BLIP-mediated suppression of Th17-associated chromatin accessibility corresponded with a marked decrease in bZIP family transcription factor binding sites. These results support the utility and further evaluation of BLIPs as an immunomodulatory agent for autoimmune disorders that are characterized by chronic inflammation and pathogenic inflammatory T cells.

3D-Bioprinted Phantom with Human Skin Phototypes for Biomedical Optics.

3D-bioprinted skin-mimicking phantoms with skin colors ranging across the Fitzpatrick scale are reported. These tools can help understand the impact of skin phototypes on biomedical optics. Synthetic melanin nanoparticles of different sizes (70-500 nm) and clusters are fabricated to mimic the optical behavior of melanosome. The absorption coefficient and reduced scattering coefficient of the phantoms are comparable to real human skin. Further the melanin content and distribution in the phantoms versus real human skins are validated via photoacoustic (PA) imaging. The PA signal of the phantom can be improved by: 1) increasing melanin size (3-450-fold), 2) increasing clustering (2-10.5-fold), and 3) increasing concentration (1.3-8-fold). Then, multiple biomedical optics tools (e.g., PA, fluorescence imaging, and photothermal therapy) are used to understand the impact of skin tone on these modalities. These well-defined 3D-bioprinted phantoms may have value in translating biomedical optics and reducing racial bias.

Intensive care unit adaptations in the COVID-19 pandemic: Lessons learned.

The coronavirus disease 2019 pandemic had deleterious effects on the healthcare systems around the world. To increase intensive care units (ICUs) bed capacities, multiple adaptations had to be made to increase surge capacity. In this editorial, we demonstrate the changes made by an ICU of a midwest community hospital in the United States. These changes included moving patients that used to be managed in the ICU to progressive care units, such as patients requiring non-invasive ventilation and high flow nasal cannula, ST-elevation myocardial infarction patients, and post-neurosurgery patients. Additionally, newer tactics were applied to the processes of assessing oxygen supply and demand, patient care rounds, and post-ICU monitoring.

Lipid-based regulators of immunity.

Lipids constitute a diverse class of molecular regulators with ubiquitous physiological roles in sustaining life. These carbon-rich compounds are primarily sourced from exogenous sources and may be used directly as structural cellular building blocks or as a substrate for generating signaling mediators to regulate cell behavior. In both of these roles, lipids play a key role in both immune activation and suppression, leading to inflammation and resolution, respectively. The simple yet elegant structural properties of lipids encompassing size, hydrophobicity, and molecular weight enable unique biodistribution profiles that facilitate preferential accumulation in target tissues to modulate relevant immune cell subsets. Thus, the structural and functional properties of lipids can be leveraged to generate new materials as pharmacological agents for potently modulating the immune system. Here, we discuss the properties of three classes of lipids: polyunsaturated fatty acids, short-chain fatty acids, and lipid adjuvants. We describe their immunoregulatory functions in modulating disease pathogenesis in preclinical models and in human clinical trials. We conclude with an outlook on harnessing the diverse and potent immune modulating properties of lipids for immunoregulation.

A Case of Medial Tibial Crest Friction Syndrome: A Rare Cause of Medial Knee Pain.

ABSTRACT: Knee pain is among the most common problems in active patients, with common causes of medial knee pain including meniscal injury, osteoarthritis, medial collateral ligament (MCL) injury, and pes anserine bursopathy/distal hamstring tendinopathy. Some cases of medial knee pain are refractory to standard treatment options and may be caused by rare pathology. We present a case of medial knee pain secondary to medial tibial crest friction syndrome (MTCFS) in a 22-year-old male training for a sprint triathlon after rapidly increasing his training program. Magnetic resonance imaging revealed bone marrow and soft-tissue edema about the MTC deep to the MCL consistent with MTCFS. The patient failed a period of relative rest and activity modification, but improved with corticosteroid injection deep to the MCL in the location of his symptoms. This case highlights a potential management option for MTCFS, a disorder previously described only in radiologic literature.

Ultrasound-Guided Iliopsoas Tendon Release: A Cadaveric Investigation.

BACKGROUND: The iliopsoas is a common source of anterior hip pain. Refractory cases may require surgical intervention, with reported complication rates ranging from 3% to 50%. Development of a minimally invasive, outpatient method of iliopsoas tendon release is desirable and may reduce costs, lower complications, and improve recovery time. OBJECTIVE: To describe and evaluate the safety and reproducibility of an ultrasound-guided (USG) iliopsoas tendon release using a spinal needle in a cadaveric model. DESIGN: Prospective, cadaveric laboratory investigation. SETTING: Academic Institution Procedural Skills Laboratory. PARTICIPANTS: Five unembalmed cadaveric specimens (three female, two male), 69 to 93 years of age (mean 83.2 years), with a mean body mass index (BMI) of 24.5 kg/m2 (range 19.2 to 30.3 kg/m2 ). INTERVENTIONS: Two operators each performed five USG iliopsoas tendon releases. Three additional investigators dissected the pelves to assess completeness of tendon release and damage to adjacent structures. MAIN OUTCOME MEASURES: Successful transection, completeness (%) of the tendon transection, damage to adjacent structures, and procedural time. RESULTS: Nine of 10 releases achieved the target release of ≥75% tendon transection. One procedure achieved 50% tendon release. No injury to adjacent structures was identified. The mean duration of the procedure was 6.19 minutes. CONCLUSIONS: USG iliopsoas tendon release can be performed in a cadaveric model, consistently achieve the desired percentage of tendon release, does not result in injury to adjacent neurovascular structures, and takes approximately 6 minutes to perform. Although results cannot be generalized to a clinical setting, due to the minimally invasive nature of the procedure, it is likely that this procedure can be performed safely in an outpatient setting under local anesthesia, will cost less, and will facilitate a more rapid recovery when compared to standard surgical procedures. Further research is warranted for clinical application.

Ultrasound-Guided Fasciotomy for Chronic Exertional Compartment Syndrome: A Case Report.

Chronic exertional compartment syndrome (CECS) is characterized by an excessive increase in intracompartmental muscle pressures after exercise. Athletes with CECS report pain, pressure, and occasionally neurologic symptoms in the affected compartment during exercise that abates with rest. Although many treatment options have been proposed, athletes often require a fasciotomy to return to unrestricted sports participation. Surgical success rates vary; complications are not uncommon; and after surgery, it usually takes athletes 6 or more weeks to return to unrestricted impact activities. This case report describes a new ultrasound-guided fasciotomy technique for the treatment of anterior leg compartment CECS. The procedure required a 3 mm incision, was performed in the office under local anesthesia, and allowed the athlete to resume running within 1 week of the procedure. Although the preliminary results of this study are promising, further translational research is required before the widespread adoption of this procedure is recommended.

Winter Adaptive Sports Participation, Injuries, and Equipment.

As the participation rate and popularity of winter adaptive sports increases, understanding injury patterns and equipment is crucial for athletes, coaches, athletic trainers, sports physicians, prosthetists/orthotists, and all the staff involved. While the inaugural Winter Paralympics in 1976 had 17 participating countries, the most recent paralympic games in Pyeongchang, South Korea had >500 athletes from 49 different countries competing in 6 disciplines: alpine skiing, nordic skiing, sledge hockey, wheelchair curling, biathlon, and snowboarding. In this paper, we review participation rates, injury trends and equipment, with a focus on the 3 most popular events: alpine skiing, nordic skiing, and sledge hockey. Despite injury risk within this athletic community, there are documented advantages to physical movement, and for each individual the risks of injury have to be weighted with the benefits of competing. Overall, there is a need for educational efforts regarding the development, access, and participation to injury prevention programs with an integrated and multidisciplinary approach.

Induction and analysis of epithelial to mesenchymal transition.

Epithelial to mesenchymal transition (EMT) is essential for proper morphogenesis during development. Misregulation of this process has been implicated as a key event in fibrosis and the progression of carcinomas to a metastatic state. Understanding the processes that underlie EMT is imperative for the early diagnosis and clinical control of these disease states. Reliable induction of EMT in vitro is a useful tool for drug discovery as well as to identify common gene expression signatures for diagnostic purposes. Here we demonstrate a straightforward method for the induction of EMT in a variety of cell types. Methods for the analysis of cells pre- and post-EMT induction by immunocytochemistry are also included. Additionally, we demonstrate the effectiveness of this method through antibody-based array analysis and migration/invasion assays.

Synthesis and evaluation of substrate analogue inhibitors of trypanothione reductase.

Trypanothione reductase (TR) is found in the trypanosomatid parasites, where it catalyses the NADPH-dependent reduction of the glutathione analogue, trypanothione, and is a key player in the parasite's defenses against oxidative stress. TR is a promising target for the development of antitrypanosomal drugs; here, we report our synthesis and evaluation of compounds 3-5 as low micromolar Trypanosoma cruzi TR inhibitors. Although 4 and 5 were designed as potential irreversible inhibitors, these compounds, as well as 3, displayed reversible competitive inhibition. Compound 3 proved to be the most potent inhibitor, with a K(i) = 2 µM.

Overview of the generation, validation, and application of phosphosite-specific antibodies.

Protein phosphorylation is a universal key posttranslational modification that affects the activity and other properties of intracellular proteins. Phosphosite-specific antibodies can be produced as polyclonals or monoclonals in different animal species, and each approach offers its own benefits and disadvantages. The validation of phosphosite-specific antibodies requires multiple techniques and tactics to demonstrate their specificity. These antibodies can be used in arrays, flow cytometry, and imaging platforms. The specificity of phosphosite-specific antibodies is key for their use in proteomics and profiling of disease.

Allele-specific suppressors of lin-1(R175Opal) identify functions of MOC-3 and DPH-3 in tRNA modification complexes in Caenorhabditis elegans.

The elongator (ELP) complex consisting of Elp1-6p has been indicated to play roles in multiple cellular processes. In yeast, the ELP complex has been shown to genetically interact with Uba4p/Urm1p and Kti11-13p for a function in tRNA modification. Through a Caenorhabditis elegans genetic suppressor screen and positional cloning, we discovered that loss-of-function mutations of moc-3 and dph-3, orthologs of the yeast UBA4 and KTI11, respectively, effectively suppress the Multivulva (Muv) phenotype of the lin-1(e1275, R175Opal) mutation. These mutations do not suppress the Muv phenotype caused by other lin-1 alleles or by gain-of-function alleles of ras or raf that act upstream of lin-1. The suppression can also be reverted by RNA interference of lin-1. Furthermore, we showed that dph-3(lf) also suppressed the defect of lin-1(e1275) in promoting the expression of a downstream target (egl-17). These results indicate that suppression by the moc-3 and dph-3 mutations is due to the elevated activity of lin-1(e1275) itself rather than the altered activity of a factor downstream of lin-1. We further showed that loss-of-function mutations of urm-1 and elpc-1-4, the worm counterparts of URM1 and ELP complex components in yeast, also suppressed lin-1(e1275). We also confirmed that moc-3(lf) and dph-3(lf) have defects in tRNA modifications as do the mutants of their yeast orthologs. These results, together with the observation of a likely readthrough product from a lin-1(e1275)::gfp fusion transgene indicate that the aberrant tRNA modification led to failed recognition of a premature stop codon in lin-1(e1275). Our genetic data suggest that the functional interaction of moc-3/urm-1 and dph-3 with the ELP complex is an evolutionarily conserved mechanism involved in tRNA functions that are important for accurate translation.