Targeting macrophages with multifunctional nanoparticles to detect and prevent atherosclerotic cardiovascular disease

Despite the emergence of novel diagnostic, pharmacological, interventional and prevention strategies, atherosclerotic cardiovascular disease remains a significant cause of morbidity and mortality. Nanoparticle-based platforms encompass diverse imaging, delivery and pharmacological properties that provide novel opportunities for refining diagnostic and therapeutic interventions for atherosclerosis at the cellular and molecular level. Macrophages play a critical role in atherosclerosis and therefore represent an important disease-related diagnostic and therapeutic target, especially given their inherent ability for passive and active nanoparticle uptake. In this review, we discuss an array of inorganic, carbon-based and lipid-based nanoparticles that provide magnetic, radiographic and fluorescent imaging capabilities for a range of highly promising research and clinical applications in atherosclerosis. We discuss the design of nanoparticles that target a range of macrophage-related functions such as lipoprotein oxidation, cholesterol efflux, vascular inflammation and defective efferocytosis. We also provide examples of nanoparticle systems that were developed for other pathologies such as cancer and highlight their potential for repurposing in cardiovascular disease. Finally, we discuss the current state of play and the future of theranostic nanoparticles. Whilst this is not without its challenges, the array of multifunctional capabilities that are possible in nanoparticle design ensures they will be part of the next frontier of exciting new therapies that simultaneously improve the accuracy of plaque diagnosis and more effectively reduce atherosclerosis with limited side effects.

Perineuronal net structure as a non-cellular mechanism contributing to affective state: A scoping review

Affective state encompasses emotional responses to our physiology and influences how we perceive and respond within our environment. In affective disorders such as depression, cognitive adaptability is challenged, and structural and functional brain changes have been identified. However, an incomplete understanding persists of the molecular and cellular mechanisms at play in affective state. An exciting area of newly appreciated importance is perineuronal nets (PNNs); a specialised component of extracellular matrix playing a critical role in neuroprotection and synaptic plasticity. A scoping review found 24 studies demonstrating that PNNs are still a developing field of research with a promising general trend for stress in adulthood to increase the intensity of PNNs, whereas stress in adolescence reduced (potentially developmentally delayed) PNN numbers and intensity, while antidepressants correlated with reduced PNN numbers. Despite promising trends, limited research underscores the need for further exploration, emphasizing behavioral outcomes for validating affective states. Understanding PNNs' role may offer therapeutic insights for depression and inform biomarker development, advancing precision medicine and enhancing well-being.

Investigation of the mechanisms for wireless nerve stimulation without active electrodes

Electric-field stimulation of neuronal activity can be used to improve the speed of regeneration for severed and damaged nerves. Most techniques, however, require invasive electronic circuitry which can be uncomfortable for the patient and can damage surrounding tissue. A recently suggested technique uses a graft-antenna-a metal ring wrapped around the damaged nerve-powered by an external magnetic stimulation device. This technique requires no electrodes and internal circuitry with leads across the skin boundary or internal power, since all power is provided wirelessly. This paper examines the microscopic basic mechanisms that allow the magnetic stimulation device to cause neural activation via the graft-antenna. A computational model of the system was created and used to find that under magnetic stimulation, diverging electric fields appear at the metal ring's edges. If the magnetic stimulation is sufficient, the gradients of these fields can trigger neural activation in the nerve. In-vivo measurements were also performed on rat sciatic nerves to support the modeling finding that direct contact between the antenna and the nerve ensures neural activation given sufficient magnetic stimulation. Simulations also showed that the presence of a thin gap between the graft-antenna and the nerve does not preclude neural activation but does reduce its efficacy.

The pharmacology and therapeutic role of cannabidiol in diabetes

In recent years, cannabidiol (CBD), a non-psychotropic cannabinoid, has garnered substantial interest in drug development due to its broad pharmacological activity and multi-target effects. Diabetes is a chronic metabolic disease that can damage multiple organs in the body, leading to the development of complications such as abnormal kidney function, vision loss, neuropathy, and cardiovascular disease. CBD has demonstrated significant therapeutic potential in treating diabetes mellitus and its complications owing to its various pharmacological effects. This work summarizes the role of CBD in diabetes and its impact on complications such as cardiovascular dysfunction, nephropathy, retinopathy, and neuropathy. Strategies for discovering molecular targets for CBD in the treatment of diabetes and its complications are also proposed. Moreover, ways to optimize the structure of CBD based on known targets to generate new CBD analogues are explored.

Mouse brain glycomics - Insights from exploring the Allen Brain Atlas and the implications for the neuroimmune brain

The Allen Institute Mouse Brain Atlas, with visualisation using the Brain Explorer software, offers a 3-dimensional view of region-specific RNA expression of thousands of mouse genes. In this Viewpoint, we focused on the region-specific expression of genes related to cellular glycosylation, and discuss their relevance towards psychoneuroimmunology. Using specific examples, we show that the Atlas validates existing observations reported by others, identifies previously unknown potential region-specific glycan features, and highlights the need to promote collaborations between glycobiology and psychoneuroimmunology researchers.

Physical Examination Maneuvers for SLAP Lesions: A Systematic Review and Meta-analysis of Individual and Combinations of Maneuvers

BACKGROUND

Superior labrum anterior to posterior (SLAP) lesions are targeted on physical examination using a variety of provocative maneuvers.

PURPOSE/HYPOTHESIS

The purpose was to conduct a systematic review on the performance of physical examination maneuvers in diagnosing SLAP lesions and to perform a meta-analysis comparing the sensitivity and specificity of these examinations both individually and in combination. The null hypothesis stated that there would be no significant difference in the sensitivity or specificity of the included physical examination tests, neither individually nor in combination.

STUDY DESIGN

Meta-analysis and systematic review; Level of evidence, 4.

METHODS

A systematic review was performed with the inclusion criteria of studies that reported either the sensitivities and specificities or the number of true-positive, true-negative, false-positive, or false-negative results for at least 1 maneuver for identifying SLAP lesions. A meta-analysis was performed to determine the sensitivity and specificity of individual maneuvers. Additional analysis determined the performance of these maneuvers when combined in series and parallel. In series, all must be present to be considered positive. In parallel, any single positive test forces the overall combination to be considered positive. Only tests that were included in ≥3 studies were considered in the meta-analysis and those included in ≥4 studies were considered in the combination analysis.

RESULTS

Overall, 862 studies were identified, 18 of which were included in the systematic review and meta-analysis. The physical examinations included were the O'Brien (n = 16), speed (n = 8), Yergason (n = 6), anterior slide (n = 8), crank (n = 7), Jobe (n = 5), dynamic labral shear (n = 3), Kim 2 (n = 3), and biceps groove tenderness tests (n = 3). All combinations of 2 to 5 maneuvers in both series and parallel were considered. The O'Brien and crank test combination was the most sensitive 2-test combination in both parallel and series. The Yergason and anterior slide test combination was the most specific 2-test combination in parallel and series.

CONCLUSION

This systematic review and meta-analysis reports an updated meta-analysis considering the sensitivity and specificity of common physical examination maneuvers used in the diagnosis of SLAP lesions and considers these values for tests in both series and parallel combinations. The present analysis demonstrates improved specificities when tests are considered in series and improved sensitivities when considered in parallel combination.

Global Alliance for the Promotion of Physical Activity: the Hamburg Declaration

Non-communicable diseases (NCDs), including coronary heart disease, stroke, hypertension, type 2 diabetes, dementia, depression and cancers, are on the rise worldwide and are often associated with a lack of physical activity (PA). Globally, the levels of PA among individuals are below WHO recommendations. A lack of PA can increase morbidity and mortality, worsen the quality of life and increase the economic burden on individuals and society. In response to this trend, numerous organisations came together under one umbrella in Hamburg, Germany, in April 2021 and signed the 'Hamburg Declaration'. This represented an international commitment to take all necessary actions to increase PA and improve the health of individuals to entire communities. Individuals and organisations are working together as the 'Global Alliance for the Promotion of Physical Activity' to drive long-term individual and population-wide behaviour change by collaborating with all stakeholders in the community: active hospitals, physical activity specialists, community services and healthcare providers, all achieving sustainable health goals for their patients/clients. The 'Hamburg Declaration' calls on national and international policymakers to take concrete action to promote daily PA and exercise at a population level and in healthcare settings.

Acute Compartment Syndrome in the Athlete

In sports, acute compartment syndrome (ACS) develops following lower limb fracture, with subsequent high intracompartmental pressures and pain out of proportion to the physical examination. A prompt diagnosis is the key to a successful outcome in patients with ACS. The goal of treatment of ACS, namely decompressive fasciotomy, is to reduce intracompartmental pressure and facilitate reperfusion of ischemic tissue before onset of necrosis. A delay in diagnosis and treatment may result in devastating complications, including permanent sensory and motor deficits, contractures, infection, systemic organ failure, limb amputation, and death.

One immune system plays many parts: The dynamic role of the immune system in chronic pain and opioid pharmacology

The transition from acute to chronic pain is an ongoing major problem for individuals, society and healthcare systems around the world. It is clear chronic pain is a complex multidimensional biological challenge plagued with difficulties in pain management, specifically opioid use. In recent years the role of the immune system in chronic pain and opioid pharmacology has come to the forefront. As a highly dynamic and versatile network of cells, tissues and organs, the immune system is perfectly positioned at the microscale level to alter nociception and drive structural adaptations that underpin chronic pain and opioid use. In this review, we highlight the need to understand the dynamic and adaptable characteristics of the immune system and their role in the transition, maintenance and resolution of chronic pain. The complex multidimensional interplay of the immune system with multiple physiological systems may provide new transformative insight for novel targets for clinical management and treatment of chronic pain. This article is part of the Special Issue on "Opioid-induced changes in addiction and pain circuits".

Gender-specific effects of COVID-19 lockdowns on scientific publishing productivity: Impact and resilience

RATIONALE

The SARS-CoV2 pandemic led to drastic social restrictions globally. Early data suggest that women in science have been more adversely affected by these lockdowns than men, with relatively fewer scientific articles authored by women. However, these observations test broad populations with many potential causes of disparity. Australia presents a natural experimental condition where several states of similar demographics and disease impact had differing approaches in their social isolation strategies. The state of Victoria experienced 280 days of lockdowns from 2020 to 2021, whereas the comparable state of New South Wales experienced 107 days, most of these in 2021, and other states even fewer restrictions.

OBJECTIVE AND METHODS

To assess how the gender balance changed in Australian biomedical publishing with the lockdowns, we created a custom workflow to analyse PubMed data from more than 120,000 published articles submitted in 2019-2021 from Australian authors.

RESULTS

Broadly, Australian women have been incredibly resilient to the challenges faced by the lockdowns. There was an increase in the number of published articles submitted in 2020 that was equally due to women as men, including from Victoria. On the other hand, articles specifically addressing COVID-19 were significantly less likely to be authored by women than those on other topics, a finding not likely due to particular gender imbalance in virology or viral epidemiology, since publications on HIV followed similar patterns to previous years. By 2021, this imbalance had reversed, with more COVID-19-related papers authored by women than men.

CONCLUSIONS

These data suggest women from Victoria were less able to rapidly transition to new research early in the pandemic but had accommodated to the new conditions by 2021. This work indicates we need strategies to support women in science as the pandemic continues and to continue to monitor the situation for its impact on vulnerable groups.

Traumatic brain injuries in paediatric patients: individual vs. team sports-related hospitalizations

Paediatric sport participation continues to increase in the United States, with a corresponding increase in sports-related concussions or traumatic brain injuries (TBIs). It is important to recognize which sports are at elevated risk and identify risk factors for hospital admission and length of stay (LOS). Paediatric patients (ages 5-18) from 2008 to 2014 were identified from the Healthcare Cost and Utilization Project (HCUP) National Inpatient Sample (NIS). Eight hundred and ninety-four patients included those who were hospitalized with a TBI resulting from participation in an individual (451 patients) or team (443 patients) sport. We evaluated the differences in LOS and total charges between individual and team sports and found that compared to team sports, TBI patients in individual sports had significantly longer hospital stays compared to team sports (1.75 days versus 1.34 days, p < 0.001) and costlier ($27,333 versus $19,069, p < 0.001) hospital stays. This may be due to reduced awareness and reduced compliance with return-to-play protocols in individual sports. Safety education information at a young age, increased awareness of TBIs, and additional medical support for individual sports as well as team sports may help mitigate these findings.

Study protocol: an observational study of distress, immune function and persistent pain in HIV

INTRODUCTION

Many people with HIV report both distress and pain. The relationship between distress and pain is bidirectional, but the mechanisms by which distress exacerbates pain are unclear. The inflammatory response to challenge (inflammatory reactivity, IR) may be a partial mediator, given that neuroimmune interactions provide a substrate for IR to also influence neurological reactivity and, thus, pain-related neural signalling. This prospective, observational, case-control study will characterise the relationships between distress, IR, pain-related signalling as captured by induced secondary hyperalgesia (SH), and pain, in people with HIV who report persistent pain (PP) (cases) or no pain (controls).

METHODS AND ANALYSIS

One hundred people with suppressed HIV, reporting either PP or no pain, will be assessed two or four times over 6 months. The primary outcomes are distress (Hopkins 25-item symptom checklist), IR (multiplex assay after LPS challenge), and PP (Brief Pain Inventory), assessed at the baseline timepoint, although each will also be assessed at follow-up time points. Induced SH will be assessed in a subsample of 60 participants (baseline timepoint only). To test the hypothesis that IR partly mediates the relationship between distress and pain, mediation analysis will use the baseline data from the PP group to estimate direct and indirect contributions of distress and IR to pain. To test the hypothesis that IR is positively associated with SH, data from the subsample will be analysed with generalised mixed effects models to estimate the association between IR and group membership, with SH as the dependent variable.

ETHICS AND DISSEMINATION

Information obtained from this study will be published in peer-reviewed journals and presented at scientific meetings. The study has been approved by the Human Research Ethics Committee of the University of Cape Town (approval number: 764/2019) and the City of Cape Town (ref: 24699).

TRIAL REGISTRATION NUMBER

NCT04757987.

The Neuroimmune Interface and Chronic Pain Through the Lens of Production Animals

Communication between the central nervous system (CNS) and the immune system has gained much attention for its fundamental role in the development of chronic and pathological pain in humans and rodent models. Following peripheral nerve injury, neuroimmune signaling within the CNS plays an important role in the pathophysiological changes in pain sensitivity that lead to chronic pain. In production animals, routine husbandry procedures such as tail docking and castration, often involve some degree of inflammation and peripheral nerve injury and consequently may lead to chronic pain. Our understanding of chronic pain in animals is limited by the difficulty in measuring this pathological pain state. In light of this, we have reviewed the current understanding of chronic pain in production animals. We discuss our ability to measure pain and the implications this has on animal welfare and production outcomes. Further research into the neuroimmune interface in production animals will improve our fundamental understanding of chronic pain and better inform human clinical pain management and animal husbandry practices and interventions.

Toll-like receptors change morphine-induced antinociception, tolerance and dependence: Studies using male and female TLR and signalling gene KO mice

Toll-like receptors (TLR) have been proposed as a site of action that alters opioid pharmacodynamics. However, a comprehensive assessment of acute opioid antinociception, tolerance and withdrawal behaviours in genetic null mutant strains with altered innate immune signalling has not been performed. Nor has the impact of genetic deletion of TLR2/4 on high-affinity opioid receptor binding. Here we show that diminished TLR signalling potentiates acute morphine antinociception equally in male and female mice. However, only male TIR8 null mutant mice showed reduced morphine analgesia. Analgesic tolerance was prevented in TLR2 and TLR4 null mutants, but not MyD88 animals. Withdrawal behaviours were only protected in TLR2^-/- mice. In silico docking simulations revealed opioid ligands bound preferentially to the LPS binding pocket of MD-2 rather than TLR4. There was no binding of [³H](-)-naloxone or [³H]diprenorphine to TLR4 in the concentrations explored. These data confirm that opioids have high efficacy activity at innate immune pattern recognition binding sites but do not bind to TLR4 and identify critical pathway and sex-specific effects of the complex innate immune signalling contributions to opioid pharmacodynamics. These data further support the behavioural importance of the TLR-opioid interaction but fail to demonstrate direct evidence for high-affinity binding of the TLR4 signalling complex to ligands.

Glial-modulating agents for the treatment of pain: protocol for a systematic review

INTRODUCTION

Evidence suggests a role for Central nervous system glia in pain transmission and in augmenting maladaptive opioid effects. Identification of drugs that modulate glia has guided the evaluation of glial suppression as a pain management strategy. This planned systematic review will describe evidence of the efficacy and adverse effects of glial-modulating drugs in pain management.

METHODS AND ANALYSIS

A detailed search will be conducted on the Cochrane Central Register of Controlled Trials, Medline, and Embase from their inception until the date the final searches are run to identify relevant randomised controlled trials. The reference lists of retrieved studies, as well as online trial registries, will also be searched. English language, randomised, double-blind trials comparing various glial-modulating drugs with placebo and/or other comparators, with participant-reported pain assessment, will be included. Two reviewers will independently evaluate studies for eligibility, extract data and assess trial quality and potential bias. Risk of bias will be assessed using criteria outlined in the Cochrane Handbook for Systematic Review of Interventions. Primary outcomes for this review will include any validated measure of pain intensity and/or pain relief. Dichotomous data will be used to calculate risk ratio and number needed to treat or harm. The quality of evidence will be assessed using Grading of Recommendations Assessment, Development and Evaluation.

ETHICS AND DISSEMINATION

This systematic review does not require formal ethics approval. The findings will be disseminated through peer-reviewed publications and conference presentations.

PROSPERO REGISTRATION NUMBER

CRD42021262074.

Toll-Like Receptor 4 in Pain: Bridging Molecules-to-Cells-to-Systems

Pain impacts the lives of billions of people around the world - both directly and indirectly. It is complex and transcends beyond an unpleasant sensory experience to encompass emotional experiences. To date, there are no successful treatments for sufferers of chronic pain. Although opioids do not provide any benefit to chronic pain sufferers, they are still prescribed, often resulting in more complications such as hyperalgesia and dependence. In order to develop effective and safe medications to manage, and perhaps even treat pain, it is important to evaluate novel contributors to pain pathologies. As such, in this chapter we review the role of Toll-like receptor 4, a receptor of the innate immune system, that continues to gain substantial attention in the field of pain research. Positioned in the nexus of the neuro and immune systems, TLR4 may provide one of the missing pieces in understanding the complexities of pain. Here we consider how TLR4 enables a mechanistical understanding of pain as a multidimensional biopsychosocial state from molecules to cells to systems and back again.

Androgens, Endometriosis and Pain

The intriguing relationship between androgens, endometriosis and chronic pain continues to unfold. Determining this relationship is of crucial importance to gynecologists managing people with these conditions, as common treatments dramatically alter her hormonal profiles, with both intended and unintended consequences. Although they may be present in the same individual, there is a recognized disconnect between pain or pain-related symptoms, and the presence or extent of endometriosis lesions. Reduced androgen levels provide a potential mechanism to link the development of endometriosis lesions and the presence of chronic pain. This research paper expands the presentation of our research at the World Endometriosis Congress in 2021, subsequently published in the Journal of Pain Research which demonstrated a strong inverse relationship between androgen levels and days per month of pelvic and period pain. Here we extend and further explore the evidence for a role for androgens in the etiology and management of dysmenorrhea and pelvic pain in women, both with and without endometriosis. We explore the potential for inflammation to induce low androgen levels and consider ways in which clinicians can optimize levels of androgens when treating women with these conditions. This article prompts the question: Is it estrogens that predispose people to a life of pain, or androgens that are protective?

Autofluorescent imprint of chronic constriction nerve injury identified by deep learning

Our understanding of chronic pain and the underlying molecular mechanisms remains limited due to a lack of tools to identify the complex phenomena responsible for exaggerated pain behaviours. Furthermore, currently there is no objective measure of pain with current assessment relying on patient self-scoring. Here, we applied a fully biologically unsupervised technique of hyperspectral autofluorescence imaging to identify a complex signature associated with chronic constriction nerve injury known to cause allodynia. The analysis was carried out using deep learning/artificial intelligence methods. The central element was a deep learning autoencoder we developed to condense the hyperspectral channel images into a four- colour image, such that spinal cord tissue based on nerve injury status could be differentiated from control tissue. This study provides the first validation of hyperspectral imaging as a tool to differentiate tissues from nerve injured vs non-injured mice. The auto-fluorescent signals associated with nerve injury were not diffuse throughout the tissue but formed specific microscopic size regions. Furthermore, we identified a unique fluorescent signal that could differentiate spinal cord tissue isolated from nerve injured male and female animals. The identification of a specific global autofluorescence fingerprint associated with nerve injury and resultant neuropathic pain opens up the exciting opportunity to develop a diagnostic tool for identifying novel contributors to pain in individuals.

Long-term intrathecal administration of morphine vs. baclofen: Differences in CSF glycoconjugate profiles using multiglycomics

Opioid use for treatment of persistent pain has increased dramatically over the past two decades, but it has not resulted in improved pain management outcomes. To understand the molecular mechanisms of opioids, molecular signatures that arise from opioid exposure are often sought after, using various analytical methods. In this study, we performed proteomics, and multiglycomics via sequential analysis of polysialic acids, glycosaminoglycans, N-glycans and O-glycans, using the same cerebral spinal fluid (CSF) sample from patients that had long-term (>2 years), intrathecal morphine or baclofen administered via an indwelling pump. Proteomics and N-glycomics signatures between the two treatment groups were highly conserved, while significant differences were observed in polysialic acid, heparan sulfate glycosaminoglycan and O-glycan profiles between the two treatment groups. This represents the first study to investigate the potential relationships between diverse CSF conjugated glycans and long-term intrathecal drug exposure. The unique changes, observed by a sequential analytical workflow, reflect previously undescribed molecular effects of opioid administration and pain management.

Effects of Mild and Moderate Monoclonal Antibody Dose on Inflammation, Bone Loss, and Activation of the Central Nervous System in a Female Collagen Antibody-induced Arthritis Mouse Model

Induction of severe inflammatory arthritis in the collagen antibody-induced arthritis (CAIA) murine model causes extensive joint damage and pain-like behavior compromising analysis. While mild models are less severe, their reduced, variable penetrance makes assessment of treatment efficacy difficult. This study aimed to compare macroscopic and microscopic changes in the paws, along with central nervous system activation between a mild and moderate CAIA model. Balb/c mice (n=18) were allocated to control, mild, and moderate CAIA groups. Paw inflammation, bone volume (BV), and paw volume (PV) were assessed. Histologically, the front paws were assessed for joint inflammation, cartilage damage, and pre/osteoclast-like cells and the lumbar spinal cord and the periaqueductal gray (PAG) region of the brain for glial reactivity. A moderate CAIA dose induced (1) significantly greater local paw inflammation, inflammatory cell infiltration, and PV; (2) significantly more osteoclast-like cells on the bone surface and within the surrounding soft tissue; and (3) significantly greater glial reactivity within the PAG compared with the mild CAIA model. These findings support the use of a moderate CAIA model (higher dose of monoclonal antibodies with low-dose lipopolysaccharide) to induce more consistent histopathological features, without excessive joint destruction.

Preventing Tommy John Surgery: The Identification of Trends in Pitch Selection, Velocity, and Spin Rate Before Ulnar Collateral Ligament Reconstruction in Major League Baseball Pitchers

Background:

Ulnar collateral ligament (UCL) reconstruction is a common surgery among Major League Baseball (MLB) pitchers that results in a significant number of missed games. Little has been reported regarding game-by-game trends that can identify those on the verge of becoming injured.

Purpose:

To determine if there is a patterned change in MLB pitchers’ pitch selection, velocity, or spin rate in games leading up to Tommy John surgery that may predict subsequent UCL surgery.

Study Design:

Case series; Level of evidence, 4.

Methods:

A retrospective review of MLB pitchers who underwent primary UCL reconstruction between 2009 and 2019 was performed. Pitch characteristics were evaluated on a game-by-game basis for the 15 games leading up to surgery. A Mann-Kendall trend test was used to identify trends in pitch selection, velocity, and spin rate for multiple pitch types. A Kendall τ_b correlation coefficient was identified, with values closer to 1 or –1 signifying a stronger monotonic trend.

Results:

A total of 223 MLB pitchers underwent UCL reconstruction in the time period. In the 15 games leading up to surgery, decreases in pitch velocity for 4-seam fastballs (τ_b = –0.657; P < .001), 2-seam fastballs (τ_b = –0.429; P = .029), and sliders (τ_b = –0.524; P = .008) were significantly associated with game number closer to injury. There was a significant positive association in the spin rate for cutters (τ_b = 0.410; P = .038) and a significant negative association in spin rate for 4-seam fastballs over the course of these 15 games (τ_b = –0.581; P = .003). In addition, there was a significant positive association in the percentage of curveballs thrown (τ_b = 0.486; P = .013).

Conclusion:

The study results suggest that there is a patterned change in certain pitch statistics in MLB pitchers in the games leading up to Tommy John surgery. Although the absolute change from game to game may be small, it may be possible for these trends to be monitored before a player becomes injured, thus reducing the significant burden Tommy John surgery places on these athletes.

Nicotine and its metabolite cotinine target MD2 and inhibit TLR4 signaling

Nicotine is the principal alkaloid of tobacco often manufactured into cigarettes and belongs to a highly addictive class of drugs. Nicotine attenuates the neuroinflammation induced by microglial activation. However, the molecular target(s) underlying anti-inflammatory action of nicotine has not been fully understood. Considering the psychoactive substances morphine, cocaine, and methamphetamine act as xenobiotic-associated molecular patterns and can be specifically sensed by the innate immune receptor Toll-like receptor 4 (TLR4), here we sought to delineate whether nicotine and/or its metabolite cotinine may be recognized by the innate immune system via myeloid differentiation protein 2 (MD2), an accessory protein of TLR4 that is responsible for ligand recognition. MD2-intrinsic fluorescence titrations, surface plasmon resonance, and competitive displacement binding assays with curcumin (MD2 probe) demonstrated that both nicotine and cotinine targeted the lipopolysaccharide (LPS; TLR4 agonist) binding pocket of MD2 with similar affinities. The cellular thermal shift assay indicated that nicotine binding increased, while cotinine binding decreased, MD2 stability. These biophysical binding results were further supported by in silico simulations. In keeping with targeting MD2, both nicotine and cotinine inhibited LPS-induced production of nitric oxide and tumor necrosis factor alpha (TNF-α) and blocked microglial activation. Neither a pan nicotinic acetylcholine receptor (nAChR) inhibitor nor RNAi for nAChRs abolished the suppressive effect of nicotine- and cotinine-induced neuroinflammation. These data indicate that TLR4 inhibition by nicotine and cotinine at the concentrations tested in BV-2 cells is independent of classic neuronal nAChRs and validate that MD2 is a direct target of nicotine and cotinine in the inhibition of innate immunity.

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Nicotine and cotinine bind to MD2 in microglia cell

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Nicotine and cotinine inhibit the expression of pro-inflammatory factors

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The activity of nicotine and cotinine in microglia is independent of nAChRs

Chronic Exertional Compartment Syndrome of the Leg Management Is Changing: Where Are We and Where Are We Going?

Chronic exertional compartment syndrome (CECS) is one of the wide range of causes of exercise-related leg pain in athletes. It is defined as a transient increase in compartment pressures during activity, which causes pain, because of the inability of the fascial compartments to accommodate and is usually relieved by cessation of exercise. Exercise-induced leg pain in the athletic population is a common complaint, with reports of up to 15% of all runners arriving to initial evaluation with this presentation. Often, this lower-extremity exertional pain is grouped into the common term of "shin splints" by athletes, which is a nondiagnostic term that implies no specific pathology. It may, however, encompass much of the differential for CECS, including medial tibial stress syndrome, muscle strain, and stress fracture. Improving diagnostic techniques, as well as treatments, will continue to help athletes and patients with leg pain in the future.

The Relationship Between Androgens and Days per Month of Period Pain, Pelvic Pain, Headache, and TLR4 Responsiveness of Peripheral Blood Mononuclear Cells in Young Women with Dysmenorrhoea

Purpose

Women bear a disproportionate burden of persistent pain conditions when compared to men. To determine whether the hormonal environment affects the clinical experience of pain, as measured by the days per month of pelvic pain (DPelvicPM), period pain (DPeriodPM), headache (DHeadachePM) or the in vitro EC₅₀ for Interleukin-1β (IL-1β) release following TLR4 stimulation with Lipopolysaccharide from Peripheral Blood Mononuclear Cells (PBMCs). Findings were stratified according to use or non-use of the oral contraceptive pill.

Patients and Methods

Fifty-six women aged 16–35 years, with minimal or severe dysmenorrhea, and use or non-use of the OC, were enrolled. Blood was collected on two occasions in a single menstrual cycle: Days 1–2 and Days 7–10. Hormonal analysis for testosterone, dihydrotestosterone, dehydroepiandrosterone, Androstenedione, 3α-Androstanediol, 3β-androstanediol, estradiol, estrone, 17α-hydroxyprogesterone, progesterone, cortisol and sex-hormone binding globulin was undertaken using ultra-sensitive Liquid Chromatography Mass–Spectrometry (LC-MS). PBMCs were exposed to lipopolysaccharide (LPS) and the resulting Interleukin-1β output was determined.

Results

Non-users of the OC showed a strongly inverse correlation between a reducing free androgen index (FAI) and increasing DPelvicPM (p=0.0032), DPeriodPM (p=0.013), DHeadachePM (p=0.041). Non-users of the OC showed a significant increase in DPelvicPM (p=0.049) on Days 7–10. Modestly significant associations were found between reduced androgens and potentiated LPS-induced IL-1β (lower EC₅₀).

Conclusion

This is the first study to investigate the relationship between the hormonal environment and activation of the immune system in young women with dysmenorrhoea-related pain conditions. Low androgen levels were consistently associated with increased pain. Translational implications for the findings are discussed.

Artemisinin inhibits TLR4 signaling by targeting co-receptor MD2 in microglial BV-2 cells and prevents lipopolysaccharide-induced blood-brain barrier leakage in mice

Artemisinin and its derivatives have been the frontline drugs for treating malaria. In addition to the antiparasitic effect, accumulating evidence shows that artemisinins can alleviate neuroinflammatory responses in the central nervous system (CNS). However, the precise mechanisms underlying their anti-neuroinflammatory effects are unclear. Herein we attempted to delineate the molecule target of artemisinin in microglia. In vitro protein intrinsic fluorescence titrations and saturation transfer difference (STD)-NMR showed the direct binding of artemisinin to Toll-like receptor TLR4 co-receptor MD2. Cellular thermal shift assay (CETSA) showed that artemisinin binding increased MD2 stability, which implies that artemisinin directly binds to MD2 in the cellular context. Artemisinin bound MD2 showed much less collapse during the molecular dynamic simulations, which supports the increased stability of MD2 upon artemisinin binding. Flow cytometry analysis showed artemisinin inhibited LPS-induced TLR4 dimerization and endocytosis in microglial BV-2 cells. Therefore, artemisinin was found to inhibit the TLR4-JNK signaling axis and block LPS-induced pro-inflammatory factors nitric oxide, IL-1β and TNF-α in BV-2 cells. Furthermore, artemisinin restored LPS-induced decrease of junction proteins ZO-1, Occludin and Claudin-5 in primary brain microvessel endothelial cells, and attenuated LPS-induced blood-brain barrier disruption in mice as assessed by Evans blue. In all, this study unambiguously adds MD2 as a direct binding target of artemisinin in its anti-neuroinflammatory function. The results also suggest that artemisinin could be repurposed as a potential therapeutic intervention for inflammatory CNS diseases.

The management of concussion in sport is not standardized. A systematic review

INTRODUCTION

Concussion is traumatic brain injury with associated tissue damage commonly produced by an indirect or direct head or facial trauma that can negatively impact an athletes' career and personal life. In this context, the importance on how to deal with a concussion has received attention from worldwide literature and has become a topic of enormous interest in the sports medicine arena.

OBJECTIVE

This systematic review aimed to investigate how sports-related concussion is being managed regarding athletic injuries, athletes' age, clinical signs of concussion, adopted questionnaires, as well as decision making in sports medicine.

METHODS

A systematic review of the literature was performed searching 10 electronic databases with no limitations for year of publication up to December 2019. The search terms used were: Brain Concussion, Athletes, Sports Medicine, Athletic Injuries, Clinical Decision-Making, and Decision Making. The articles were considered eligible when the studies related to populations of regular sports practitioners, professional or recreational, of any age; sports injury; articles reporting concussion evaluation in at least 30 athletes; and articles published in English, French, Portuguese, Italian. We excluded systematic review articles, reviews, editorials, sport-unrelated concussion, no questionnaire application, approaching retired athletes, consensus statement letters, author's reply to editorials, synopsis, and abstracts.

RESULTS

The parameters adopted for decision-making and management were broadly variable and were based on a variety of clinical signs or scoring outcomes from a myriad of questionnaires with little consistency in protocol or management guidelines, which could guide the average clinician.

CONCLUSION

This systematic review provides current evidence that post-concussion management in sports medicine has yet to accomplish a standardized protocol that clinicians could use to optimally care for athletes. The extensive number of manuscripts and studies addressing the topic confirms that sports-related concussion in the pediatric and adolescent population has come to the forefront in the sports medicine field.

Is There an Association Between Authors' Conflicts of Interest and Outcomes in Clinical Studies Involving Autologous Chondrocyte Implantation?

BACKGROUND

Autologous chondrocyte implantation (ACI) is an increasingly popular technique for the treatment of articular cartilage defects. Because several companies have financial interests in ACI, it is important to consider possible conflicts of interest when evaluating studies reporting outcomes of ACI.

PURPOSE

To determine whether there is an association between authors' financial conflicts of interest and the outcomes of ACI studies.

STUDY DESIGN

Cross-sectional study.

METHODS

A search of PubMed and MEDLINE databases for "autologous chondrocyte implantation" was performed. Clinical studies published after 2012 through May 15, 2019, and in English were included. Studies were determined to have financial conflicts of interest if any contributing author had relevant conflicts, either self-reported in the published study's disclosures section or reported online in the American Academy of Orthopaedic Surgeons Disclosure database or the Centers for Medicare & Medicaid Services Open Payments database. The outcomes of each study were rated as favorable, equivocal, or unfavorable based on predefined criteria and then tested for association with conflicts of interest through use of the Fisher exact test.

RESULTS

A total of 79 studies met the inclusion criteria. Nearly all studies were of level 3 or 4 evidence. Conflicts of interest were established in 51.90% of studies (n = 41). Conflicts that were not self-reported by the authors were discovered in 18% of studies. The level of evidence was not associated with conflict of interest. No statistically significant difference was found in the rate of favorable outcomes between studies with conflicts (92.68%) and those with no conflicts (81.58%) (P = .126). Publications by US authors were more likely to have financial conflicts of interest (P = .003).

CONCLUSION

Favorable results were reported in a majority of studies involving ACI. No statistical association was found between the frequency of favorable outcomes and the presence of financial conflicts of interest, country of authorship, or level of evidence. There was a trend toward more favorable outcomes in studies with conflicts of interest. Additionally, nearly 20% of publications had possible conflicts found online that were not self-reported. It is critical for orthopaedic surgeons to judiciously evaluate published studies and consider financial conflicts of interest before performing ACI techniques on patients.

Validation and Implementation of 4-domain Patient-reported Outcome Measures (PROMs) Tailored for Orthopedic Sports Medicine

The validation of a 4-domain PROM tailored to orthopedic sports medicine was performed through item generation, item scaling, validity and reliability testing, statistical analysis, as well as item reduction. Conbrach's alpha was used to verify item homogeneity, i. e. their accuracy or consistency. This PROM showed acceptable statistical accuracy and clinical applicability for a variety of surgical treatments, regardless of the anatomical injury sites. Moreover, this PROM considers the athletes' primary physical demands in an non-injured baseline condition, their motivation to continue sports practice and participation, and the influence of sports practice on their quality of life. This 4-domain PROM tailored for orthopedic sports medicine appears to be a valid tool to assess athletes and high-performing practitioners with sports injuries, recording their perception of injury, expectations of treatment; evaluation of postoperative care and treatment received, and perceived outcomes compared to their pre-injury status of physical demands in sports activity. The tool is unique, allowing direct comparisons between athletes' perception of pre-injury baseline, injury, treatment, and outcome. It will be a welcome adjunct to the sports medicine professional's tool box when assessing athlete's status and outcome after injury and intervention.

Graded peripheral nerve injury creates mechanical allodynia proportional to the progression and severity of microglial activity within the spinal cord of male mice

The reactivity of microglia within the spinal cord in response to nerve injury, has been associated with the development and maintenance of neuropathic pain. However, the temporal changes in microglial reactivity following nerve injury remains to be defined. Importantly, the magnitude of behavioural allodynia displayed and the relationship to the phenotypic microglial changes is also unexplored. Using a heterozygous CX₃CR₁^gfp+ transgenic mouse strain, we monitored microglial activity as measured by cell density, morphology, process movement and process length over 14 days following chronic constriction of the sciatic nerve via in vivo confocal microscopy. Uniquely this relationship was explored in groups of male mice which had graded nerve injury and associated graded behavioural mechanical nociceptive sensitivity. Significant mechanical allodynia was quantified from the ipsilateral hind paw and this interacted with the extent of nerve injury from day 5 to day 14 (p < 0.009). The extent of this ipsilateral allodynia was proportional to the nerve injury from day 5 to 14 (Spearman rho = -0.58 to -0.77; p < 0.002). This approach allowed for the assessment of the association of spinal microglial changes with the magnitude of the mechanical sensitivity quantified behaviourally. Additionally, the haemodynamic response in the somatosensory cortex was quantified as a surrogate measure of neuronal activity. We found that spinal dorsal horn microglia underwent changes unilateral to the injury in density (Spearman rho = 0.47; p = 0.01), velocity (Spearman rho = -0.68; p = 0.00009), and circularity (Spearman rho = 0.55; p = 0.01) proportional to the degree of the neuronal injury. Importantly, these data demonstrate for the first time that the mechanical allodynia behaviour is not a binary all or nothing state, and that microglial reactivity change proportional to this behavioural measurement. Increased total haemoglobin levels in the somatosensory cortex of higher-grade injured animals was observed when compared to sham controls suggesting increased neuronal activity in this brain region. The degree of phenotypic microglial changes quantified here, may explain how microglia can induce both rapid onset and sustained functional changes in the spinal cord dorsal horn, following peripheral injury.

Acute stress induces the rapid and transient induction of caspase-1, gasdermin D and release of constitutive IL-1β protein in dorsal hippocampus

The proinflammatory cytokine interleukin (IL)-1β plays a pivotal role in the behavioral manifestations (i.e., sickness) of the stress response. Indeed, exposure to acute and chronic stressors induces the expression of IL-1β in stress-sensitive brain regions. Thus, it is typically presumed that exposure to stressors induces the extra-cellular release of IL-1β in the brain parenchyma. However, this stress-evoked neuroimmune phenomenon has not been directly demonstrated nor has the cellular process of IL-1β release into the extracellular milieu been characterized in brain. This cellular process involves a form of inflammatory cell death, termed pyroptosis, which involves: 1) activation of caspase-1, 2) caspase-1 maturation of IL-1β, 3) caspase-1 cleavage of gasdermin D (GSDMD), and 4) GSDMD-induced permeability of the cell membrane through which IL-1β is released into the extracellular space. Thus, the present study examined whether stress induces the extra-cellular release of IL-1β and engages the above cellular process in mediating IL-1β release in the brain. Male Sprague-Dawley rats were exposed to inescapable tailshock (IS). IL-1β extra-cellular release, caspase-1 activity and cleavage of GSDMD were measured in dorsal hippocampus. We found that exposure to IS induced a transient increase in the release of IL-1β into the extracellular space immediately after termination of the stressor. IS also induced a transient increase in caspase-1 activity prior to IL-1β release, while activation of GSDMD was observed immediately after termination of the stressor. IS also increased mRNA and protein expression of the ESCRTIII protein CHMP4B, which is involved in cellular repair. The present results suggest that exposure to an acute stressor induces the hallmarks of pyroptosis in brain, which might serve as a key cellular process involved in the release of IL-1β into the extracellular milieu of the brain parenchyma.

Sphingosine-1-phosphate receptor subtype 1 activation in the central nervous system contributes to morphine withdrawal in rodents

Opioid therapies for chronic pain are undermined by many adverse side effects that reduce their efficacy and lead to dependence, abuse, reduced quality of life, and even death. We have recently reported that sphingosine-1-phosphate (S1P) 1 receptor (S1PR1) antagonists block the development of morphine-induced hyperalgesia and analgesic tolerance. However, the impact of S1PR1 antagonists on other undesirable side effects of opioids, such as opioid-induced dependence, remains unknown. Here, we demonstrate that naloxone-precipitated morphine withdrawal in mice altered de novo sphingolipid metabolism in the dorsal horn of the spinal cord and increased S1P that accompanied the manifestation of several withdrawal behaviors. Blocking de novo sphingolipid metabolism with intrathecal administration of myriocin, an inhibitor of serine palmitoyltransferase, blocked naloxone-precipitated withdrawal. Noteworthy, we found that competitive (NIBR-15) and functional (FTY720) S1PR1 antagonists attenuated withdrawal behaviors in mice. Mechanistically, at the level of the spinal cord, naloxone-precipitated withdrawal was associated with increased glial activity and formation of the potent inflammatory/neuroexcitatory cytokine interleukin-1β (IL-1β); these events were attenuated by S1PR1 antagonists. These results provide the first molecular insight for the role of the S1P/S1PR1 axis during opioid withdrawal. Our data identify S1PR1 antagonists as potential therapeutics to mitigate opioid-induced dependence and support repurposing the S1PR1 functional antagonist FTY720, which is FDA-approved for multiple sclerosis, as an opioid adjunct.

Leadership for the Team Physician

Physician leadership of the interdisciplinary sports medicine team depends on fundamental leadership skills that often are overlooked in medical school. These leadership skills include effective communication, emotional intelligence, teamwork, selfless service, integrity, and critical thinking while utilizing an athlete-centered approach. Development of these skills will help to navigate team management and important decisions, such as return to play. The leadership session at the Advanced Team Physician Course sought to acknowledge the gap in medical training regarding leadership education and began to address it in a forum specifically for team physicians. Here we provide a summary of the lectures and presentations from the 2018 Advanced Team Physician Course in an effort to benefit a broader physician audience. This material should act as a framework for current and future team physicians to solidify their role as the leader of the medical team in caring for the athlete.

Science convergence applied to psychoneuroimmunology: The future of measurement and imaging

The future of psychoneuroimmunology requires breakthrough technology discoveries. These next generation technologies need to address the unique challenges that are raised by imaging and measuring the activity of the neuroimmune interface in health and disease. The complexity of this challenge is centred around the multidimensionality of the neuroimmune system. These include novel challenges of capturing potent and rare biological signals over long times and vast anatomical distances. Here is a summary of the outcomes of the investments made by the Australian Research Council Centre of Excellence for Nanoscale BioPhotonics which was presented as part of the PNIRSAsia-Pacific symposium at the 2019 International Brain Research Organization.

In vivo intrathecal IL-1β quantification in rats: Monitoring the molecular signals of neuropathic pain

BACKGROUND

Neuropathic pain, or pain after nerve injury, is a disorder with a significant reliance on the signalling of cytokines such as IL-1β. However, quantifying the cytokine release repeatedly over time in vivo is technically challenging.

AIM

To evaluate if changes in IL-1β are correlated with the presentation of mechanical allodynia over time, by repeatedly quantifying intrathecal IL-1β concentrations following chronic constriction injury of the sciatic nerve in rats. Also, to establish any possible correlation between biochemical spinal marker expression and the in vivo quantification of IL-1β. Finally, to assess the expression of the mature IL-1β in lumbar spinal cord samples.

METHOD

The Chronic Constriction Injury model (CCI) was used to initiate nerve injury in male Sprague Dawley rats and the generation of behavioural mechanical allodynia was quantified. Using an indwelling intrathecal catheter, a stainless steel (SS) wire biosensing device was repeatedly introduced to quantify intrathecal IL-1β concentrations at three timepoints of 0, 7, and 14 days post CCI. Fixed spinal cord samples (L4-L5), collected on day 14, were imaged for the expression of glial fibrillary acidic protein (GFAP, astrocytes) and ionized calcium binding adaptor molecule 1 (IBA1, microglia). Snap frozen spinal cord tissues (L4-L5) were also processed for western blot analysis.

RESULTS

Using the novel SS based biosensing device we established that CCI caused a significant increase in intrathecal IL-1β concentrations from day 0 to day 7 (p = 0.001) and to day 14 (p < 0.0001), while the sham group did not show any significant increase. We also further showed that the degree of mechanical allodynia correlated positively with the increase in the intrathecal concentration of IL-1β in the active CCI animals (p = 0.0007). While there was a significant increase in the ipsilateral GFAP expression in injured animals compared to sham animals (p = 0.03), we did not find any significant correlation between in vivo IL-1β concentration on days 7 and 14 and the area of dorsal horn GFAP or IBA1 positive structures on day 14. The result of western blot analysis of whole lumbar spinal cord revealed that there was no significant change (p = 0.7579) in IL-1β expression on day 14 in the CCI group compared to the sham group.

CONCLUSION

For the first time we have established that the SS based immunosensing platform technology can repeatedly sample the intrathecal space for bioactive peptides, such as IL-1β. Using this novel approach, we have been able to establish the correlation of the intrathecal concentration of IL-1β with the extent of mechanical allodynia, providing a molecular biomarker of the degree of the exaggerated pain state.

Psychoneuroimmunology goes East: Development of the PNIRSChina affiliate and its expansion into PNIRSAsia-Pacific

The Psychoneuroimmunology Research Society (PNIRS) created an official Chinese regional affiliate in 2012, designated PNIRS_China. Now, just eight years later, the program has been so successful in advancing the science of psychoneuroimmunology that it has expanded to the whole of Asia-Oceania. In 2017, PNIRS_China became PNIRS_Asia-Pacific. Between 2012 and 2019, this outreach affiliate of PNIRS organized seven symposia at major scientific meetings in China as well as nine others in Taiwan, Japan, South Korea, Australia and New Zealand. This paper summarizes the remarkable growth of PNIRS_Asia-Pacific. Here, regional experts who have been instrumental in organizing these PNIRS_Asia-Pacific symposia briefly review and share their views about the past, present and future state of psychoneuroimmunology research in China, Taiwan, Australia and Japan. The newest initiative of PNIRS_Asia-Pacific is connecting Asia-Pacific laboratories with those in Western countries through a simple web-based registration system. These efforts not only contribute to the efforts of PNIRS to serve a truly global scientific society but also to answer the imperative call of increasing diversity in our science.

Chronic Morphine-Induced Changes in Signaling at the A3 Adenosine Receptor Contribute to Morphine-Induced Hyperalgesia, Tolerance, and Withdrawal

Treating chronic pain by using opioids, such as morphine, is hampered by the development of opioid-induced hyperalgesia (OIH; increased pain sensitivity), antinociceptive tolerance, and withdrawal, which can contribute to dependence and abuse. In the central nervous system, the purine nucleoside adenosine has been implicated in beneficial and detrimental actions of morphine, but the extent of their interaction remains poorly understood. Here, we demonstrate that morphine-induced OIH and antinociceptive tolerance in rats is associated with a twofold increase in adenosine kinase (ADK) expression in the dorsal horn of the spinal cord. Blocking ADK activity in the spinal cord provided greater than 90% attenuation of OIH and antinociceptive tolerance through A₃ adenosine receptor (A₃AR) signaling. Supplementing adenosine signaling with selective A₃AR agonists blocked OIH and antinociceptive tolerance in rodents of both sexes. Engagement of A₃AR in the spinal cord with an ADK inhibitor or A₃AR agonist was associated with reduced dorsal horn of the spinal cord expression of the NOD-like receptor pyrin domain-containing 3 (60%-75%), cleaved caspase 1 (40%-60%), interleukin (IL)-1β (76%-80%), and tumor necrosis factor (50%-60%). In contrast, the neuroinhibitory and anti-inflammatory cytokine IL-10 increased twofold. In mice, A₃AR agonists prevented the development of tolerance in a model of neuropathic pain and reduced naloxone-dependent withdrawal behaviors by greater than 50%. These findings suggest A₃AR-dependent adenosine signaling is compromised during sustained morphine to allow the development of morphine-induced adverse effects. These findings raise the intriguing possibility that A₃AR agonists may be useful adjunct to opioids to manage their unwanted effects. SIGNIFICANCE STATEMENT: The development of hyperalgesia and antinociceptive tolerance during prolonged opioid use are noteworthy opioid-induced adverse effects that reduce opioid efficacy for treating chronic pain and increase the risk of dependence and abuse. We report that in rodents, these adverse effects are due to reduced adenosine signaling at the A₃AR, resulting in NOD-like receptor pyrin domain-containing 3-interleukin-1β neuroinflammation in spinal cord. These effects are attenuated by A₃AR agonists, suggesting that A₃AR may be a target for therapeutic intervention with selective A₃AR agonist as opioid adjuncts.

Small-Molecule Modulators of Toll-like Receptors

Toll-like receptors (TLRs) are the "gatekeepers" of the immune system in humans and other animals to protect the host from invading bacteria, viruses, and other microorganisms. Since TLR4 was discovered as the receptor for endotoxin in the late 1990s, significant progress has been made in exploiting an understanding of the function of TLRs. The TLR-signaling pathway is crucial for the induction and progression of various diseases. Dysregulation of TLR signaling contributes to numerous pathological conditions, including chronic inflammation, sepsis, cancers, asthma, neuropathic pain, drug addiction, and autoimmune diseases. Therefore, manipulation of TLR signaling is promising to halt their activity in inflammatory diseases, to enhance their signaling to fight cancers, to modulate their role in autoimmune diseases, and to suppress them to treat drug addiction. TLR agonists have demonstrated great potential as antimicrobial agents and vaccine adjuvants, whereas TLR antagonists are being developed as reagents and drugs to dampen immune responses. Because of their pivotal potential therapeutic applications, fruitful small-molecule compounds and peptide fragments have been discovered, and many of them have advanced to various stages of clinical trials (though only two have been approved by the Food and Drug Administration (FDA): MPLA as a TLR4 agonist and imiquimod as a TLR7 agonist).In this Account, we focus on the progress in developing TLR signaling pathway modulators (mainly focused on the Yin and Wang laboratories) over the past decade and highlight the accomplishments and currently existing challenges in the development of TLR modulators. First, we briefly describe the members of the human TLR family along with their natural modulators. Second, we illustrate our endeavors to discover TLR-targeted agents using comprehensive approaches. Specifically, a discussion of identification and characterization of new chemical entities, determination of modes of action, and further applications is presented. For instance, the TLR3 antagonist was first discovered through in silico screening, and the inhibitory activity was confirmed in murine cells. Considering the glycosylation on TLR3, a new direction for TLR3 modulator design was pointed out to target asparagine glycosylation. We have particularly focused on the discovery of TLR4 antagonists and have assessed their great potential in the clinical treatment of drug addiction and alcohol use disorders. In addition, we discuss multiple other popular and robust techniques for modulator discovery. Not only small organic modulators but also stapled peptides and peptidomimetics will attract more and more attention in the future. Finally, current challenges, opportunities, and future perspectives for TLR-targeted agents are also discussed.

Targeting Toll-like receptor-4 to tackle preterm birth and fetal inflammatory injury

Every year, 15 million pregnancies end prematurely, resulting in more than 1 million infant deaths and long-term health consequences for many children. The physiological processes of labour and birth involve essential roles for immune cells and pro-inflammatory cytokines in gestational tissues. There is compelling evidence that the mechanisms underlying spontaneous preterm birth are initiated when a premature and excessive inflammatory response is triggered by infection or other causes. Exposure to pro-inflammatory mediators is emerging as a major factor in the 'fetal inflammatory response syndrome' that often accompanies preterm birth, where unscheduled effects in fetal tissues interfere with normal development and predispose to neonatal morbidity. Toll-like receptors (TLRs) are critical upstream gatekeepers of inflammatory activation. TLR4 is prominently involved through its ability to sense and integrate signals from a range of microbial and endogenous triggers to provoke and perpetuate inflammation. Preclinical studies have identified TLR4 as an attractive pharmacological target to promote uterine quiescence and protect the fetus from inflammatory injury. Novel small-molecule inhibitors of TLR4 signalling, specifically the non-opioid receptor antagonists (+)-naloxone and (+)-naltrexone, are proving highly effective in animal models for preventing preterm birth induced by bacterial mimetic LPS, heat-killed Escherichia coli, or the TLR4-dependent pro-inflammatory lipid, platelet-activating factor (PAF). Here, we summarise the rationale for targeting TLR4 as a master regulator of inflammation in fetal and gestational tissues, and the potential utility of TLR4 antagonists as candidates for preventative and therapeutic application in preterm delivery and fetal inflammatory injury.

Toll-Like Receptor Responsiveness of Peripheral Blood Mononuclear Cells in Young Women with Dysmenorrhea

PURPOSE

Dysmenorrhea is a common disorder that substantially disrupts the lives of young women. To determine whether there is evidence of activation of the innate immune system in dysmenorrhea and whether the degree of activation may be used as a biomarker for pain, we compared the responsiveness of peripheral blood mononuclear cells (PBMCs) to toll-like receptor (TLR) 2 or 4 stimulation. We also investigated whether this effect is modulated by the use of the oral contraceptive pill (OC).

PATIENTS AND METHODS

Fifty-six women aged 16-35 years, with either severe or minimal dysmenorrhea, and use or non-use of the OC, were enrolled. PBMCs were collected on two occasions in a single menstrual cycle: the menstrual phase and the mid-follicular phase. PBMCs were exposed to lipopolysaccharide (LPS), a TLR4 agonist, and PAM3CSK4 (PAM), a TLR2 agonist, and the resulting interleukin-1beta (IL-1β) output was determined. Statistical analysis compared the EC50 between groups as a measure of TLR responsiveness of PBMCs.

RESULTS

The key finding following LPS stimulation was a pain effect of dysmenorrhea (p=0.042) that was independent of use or non-use of OC, and independent of day of testing. Women with dysmenorrhea showed a large 2.15-fold (95% CI -4.69, -0.09) increase in IL-1β release when compared with pain-free participants across both days.

CONCLUSION

This is the first study to demonstrate an ex vivo immune relationship in women with dysmenorrhea-related pelvic pain. It provides evidence for the potential of immune modulation as a novel pharmacological target for future drug development in the management of dysmenorrhea.

Zerumbone Modulates α2A-Adrenergic, TRPV1, and NMDA NR2B Receptors Plasticity in CCI-Induced Neuropathic Pain In Vivo and LPS-Induced SH-SY5Y Neuroblastoma In Vitro Models

Zerumbone has shown great potential in various pathophysiological models of diseases, particularly in neuropathic pain conditions. Further understanding the mechanisms of action is important to develop zerumbone as a potential anti-nociceptive agent. Numerous receptors and pathways function to inhibit and modulate transmission of pain signals. Previously, we demonstrated involvement of the serotonergic system in zerumbone's anti-neuropathic effects. The present study was conducted to determine zerumbone's modulatory potential involving noradrenergic, transient receptor potential vanilloid type 1 (TRPV1) and N-methyl-D-aspartate (NMDA) receptors in chronic constriction injury (CCI)-induced in vitro and lipopolysaccharide (LPS)-induced SH-SY5Y in vitro neuroinflammatory models. von Frey filament and Hargreaves plantar tests were used to assess allodynia and hyperalgesia in the chronic constriction injury-induced neuropathic pain mouse model. Involvement of specific adrenoceptors were investigated using antagonists- prazosin (α₁-adrenoceptor antagonist), idazoxan (α₂-adrenoceptor antagonist), metoprolol (β₁-adrenoceptor antagonist), ICI 118,551 (β₂-adrenoceptor antagonist), and SR 59230 A (β₃-adrenoceptor antagonist), co-administered with zerumbone (10 mg/kg). Involvement of excitatory receptors; TRPV and NMDA were conducted using antagonists capsazepine (TRPV1 antagonist) and memantine (NMDA antagonist). Western blot was conducted to investigate the effect of zerumbone on the expression of α_2A-adrenoceptor, TRPV1 and NMDA NR2B receptors in CCI-induced whole brain samples of mice as well as in LPS-induced SH-SY5Y neuroblastoma cells. Pre-treatment with α₁- and α₂-adrenoceptor antagonists significantly attenuated both anti-allodynic and anti-hyperalgesic effects of zerumbone. For β-adrenoceptors, only β₂-adrenoceptor antagonist significantly reversed the anti-allodynic and anti-hyperalgesic effects of zerumbone. β₁-adrenoceptor antagonist only reversed the anti-allodynic effect of zerumbone. The anti-allodynic and anti-hyperalgesic effects of zerumbone were both absent when TRPV1 and NMDA receptors were antagonized in both nociceptive assays. Zerumbone treatment markedly decreased the expression of α_2A-adrenoceptor, while an up-regulation was observed of NMDA NR2B receptors. Expression of TRPV1 receptors however did not significantly change. The in vitro study, representing a peripheral model, demonstrated the reduction of both NMDA NR2B and TRPV1 receptors while significantly increasing α_2A-adrenoceptor expression in contrast to the brain samples. Our current findings suggest that the α₁-, α₂-, β₁- and β₂-adrenoceptors, TRPV1 and NMDA NR2B are essential for the anti-allodynic and antihyperalgesic effects of zerumbone. Alternatively, we demonstrated the plasticity of these receptors through their response to zerumbone's administration.

Toll-Like Receptor-4 Antagonist (+)-Naltrexone Protects Against Carbamyl-Platelet Activating Factor (cPAF)-Induced Preterm Labor in Mice

Spontaneous preterm labor is frequently caused by an inflammatory response in the gestational tissues elicited by either infectious or sterile agents. In sterile preterm labor, the key regulators of inflammation are not identified, but platelet-activating factor (PAF) is implicated as a potential rate-limiting effector agent. Since Toll-like receptor (TLR)-4 can amplify PAF signaling, we evaluated whether TLR4 contributes to inflammation and fetal loss in a mouse model of PAF-induced sterile preterm labor, and whether a small-molecule TLR4 inhibitor, (+)-naltrexone, can mitigate adverse PAF-induced effects. The administration of carbamyl (c)-PAF caused preterm labor and fetal loss in wild-type mice but not in TLR4-deficient mice. Treatment with (+)-naltrexone prevented preterm delivery and alleviated fetal demise in utero elicited after cPAF administered by i.p. or intrauterine routes. Pups born after cPAF and (+)-naltrexone treatment exhibited comparable rates of postnatal survival and growth to carrier-treated controls. (+)-Naltrexone suppressed the cPAF-induced expression of inflammatory cytokine genes Il1b, Il6, and Il10 in the decidua; Il6, Il12b, and Il10 in the myometrium; and Il1b and Il6 in the placenta. These data demonstrate that the TLR4 antagonist (+)-naltrexone inhibits the inflammatory cascade induced by cPAF, preventing preterm birth and perinatal death. The inhibition of TLR4 signaling warrants further investigation as a candidate strategy for fetal protection and delay of preterm birth elicited by sterile stimuli.

Naturally-diverse airborne environmental microbial exposures modulate the gut microbiome and may provide anxiolytic benefits in mice

Growing epidemiological evidence links natural green space exposure with a range of health benefits, including for mental health. Conversely, greater urbanisation associates with increased risk of mental health disorders. Microbiomes are proposed as an important but understudied link that may help explain many green space-human health associations. However, there remains a lack of controlled experimental evidence testing possible beneficial effects from passive exposure to natural biodiversity via airborne microbiota. Previous mouse model studies have used unrealistic environmental microbial exposures-including excessive soil and organic matter contact, feed supplements and injections-to demonstrate host microbiota, immune biomarker, and behavioural changes. Here, in a randomised controlled experiment, we demonstrate that realistic exposures to trace-level dust from a high biodiversity soil can change mouse gut microbiota, in comparison to dust from low biodiversity soil or no soil (control) (n = 54 total mice, comprising 3 treatments × 18 mice, with 9 females + 9 males per group). Furthermore, we found a nominal soil-derived anaerobic spore-forming butyrate-producer, Kineothrix alysoides, was supplemented to a greater extent in the gut microbiomes of high biodiversity treatment mice. Also, increasing relative abundance of this rare organism correlated with reduced anxiety-like behaviour in the most anxious mice. Our results point to an intriguing new hypothesis: that biodiverse soils may represent an important supplementary source of butyrate-producing bacteria capable of resupplying the mammalian gut microbiome, with potential for gut health and mental health benefits. Our findings have potential to inform cost-effective population health interventions through microbiome-conscious green space design and, ultimately, the mainstreaming of biodiversity into health care.