The Putative Role of Neuroinflammation in the Interaction between Traumatic Brain Injuries, Sleep, Pain and Other Neuropsychiatric Outcomes: A State-of-the-Art Review

A pilot investigation on inflammatory markers and theta burst stimulation protocol interaction along a three-month recovery course following an isolated upper limb fracture

This study investigates the effects of theta burst stimulation (TBS) on inflammatory markers in patients with isolated upper limb fractures (IULF). Participants underwent a 10-day TBS intervention following a randomized matched pair design. Blood samples collected at three time points were analyzed for inflammatory biomarkers, mainly including interleukin-1 receptor antagonist (IL-1Ra), IL-1β, and IL-6. Results revealed a significant interaction between TBS and time for IL-1Ra, indicating a more pronounced decrease in IL-1Ra expression over time in the active TBS group. However, IL-6 levels decreased over time regardless of TBS intervention, suggesting a natural decline in response to injury. No significant interaction was found for IL-1β. While IL-1Ra levels were associated with higher functional disability prior to treatment initiation, active TBS intervention led to a decrease of IL-1Ra levels at both follow-up time points. These changes were not associated with alterations in pain or disability, suggesting that TBS may primarily influence recovery processes independent of pain modulation. Notably, IL-1β levels were negatively correlated with disability in the active TBS group at the 3-month follow-up. This study sheds light on the potential of TBS to modulate inflammatory responses in orthopedic trauma, emphasizing the need for further research to elucidate its therapeutic implications. Clinical Significance: TBS may offer a promising adjunctive therapy for promoting functional recovery in patients with upper limb fractures.

Cross-Lagged Associations Among Sleep, Headache, and Pain in Pediatric Mild Traumatic Brain Injury: An A-CAP Study

OBJECTIVE

To test cross-lagged associations among sleep, headache, and pain in pediatric mild traumatic brain injury (mTBI).

SETTING, PARTICIPANTS, DESIGN

Children and adolescents aged 8.0 to 16.9 years who sustained a mTBI and presented to 1 of 5 pediatric emergency departments across Canada completed assessments at 1-week, 3 months, and 6 months post-injury as part of a larger prospective cohort study.

MAIN MEASURES

Sleep disturbance was measured using 7 sleep items from the Child Behaviour Checklist. Sleep duration was measured using average weekday and weekend sleep from the Healthy Lifestyle Behaviours Questionnaire. Pain intensity was measured using an 11-point numerical rating scale. Headache severity and associated functional impairment were measured using the Headache Impact Test and 1 item from the Health and Behaviour Inventory. Analyses included trivariate-indicator random-intercept cross-lagged panel models.

RESULTS

Of 633 recruited children, 563 were included in the current study. Headache showed significant within-person, bidirectional, cross-lagged associations with sleep disturbance and duration, as well as with pain intensity. More specifically, worse headache predicted greater sleep disturbance (1-week to 3 months and 3 months to 6 months: Bs = .47, Ps ≤ .013) and shorter sleep duration (1-week to 3 months: B = -.21, P = .006), while greater sleep disturbance predicted worse headache (1-week to 3 months: B = .08, P = .001). Worse headache also predicted higher pain intensity (1-week to 3 months & 3 months to 6 months: Bs ≥ 1.27, P s < .001), while higher pain intensity predicted worse headache (3 months to 6 months: Bs ≥ .03, Ps ≤ .042). No cross-lagged associations involving sleep disturbance or duration with pain intensity were significant.

CONCLUSIONS

Significant bi-directional, cross-lagged associations exist between headache and both sleep and pain. The findings suggest that early intervention for headaches may help prevent later sleep disturbance and pain after pediatric mTBI.

A cross-tissue transcriptome-wide association study identifies new susceptibility genes for insomnia

Despite a significant genetic component to insomnia (heritability: 22%-25%), the genetic loci that modulate insomnia risk remain limited. We used the Unified Test for Molecular Markers (UTMOST) for transcriptome-wide association studies (TWAS) across various tissues, integrating summary statistics from a Genome-Wide Association Study (GWAS) of 462,341 European participants with gene expression data from the Genotype-Tissue Expression (GTEx) project. Three validation methods (FUSION, FOCUS, and MAGMA) were used to confirm important genes. Tissue and functional enrichment analyses of insomnia-related single-nucleotide polymorphisms (SNPs) were conducted with MAGMA. Conditional and joint analyses, along with fine mapping, were used to enhance our understanding of insomnia's genetic architecture. Mendelian randomization was used to assess causal associations between significant genes and insomnia. Two novel susceptibility genes, VRK2 and MMRN1, were identified as linked to insomnia risk using four TWAS approaches. Mendelian randomization analysis suggests VRK2 increases the risk of insomnia. Tissue enrichment analyses indicated that insomnia-related SNPs were enriched in specific brain regions, including the cerebellum, frontal cortex (BA9), hypothalamus, and hippocampus. Conditional and joint analyses identified two genomic regions (2p16.1 and 4q22.1). Functional enrichment analyses showed that pathways related to insomnia involve the SMAD2/3 pathway, synaptic function, and oxidative stress. This study identifies two new candidate genes, VRK2 and MMRN1, that may contribute to insomnia risk through neurodevelopment, neuroinflammation, and synaptic function, suggesting potential therapeutic targets.NEW & NOTEWORTHY This study identifies VRK2 and MMRN1 as novel susceptibility genes for insomnia through transcriptome-wide association studies (TWAS). Mendelian randomization confirms a causal link between VRK2 and insomnia. Key brain regions, including the cerebellum and frontal cortex, and critical pathways like SMAD2/3 signaling and oxidative stress are implicated. These findings provide new insights into the genetic basis of insomnia.

Sleep deprivation-induced shifts in gut microbiota: Implications for neurological disorders

Sleep deprivation is a prevalent issue in contemporary society, with significant ramifications for both physical and mental well-being. Emerging scientific evidence illuminates its intricate interplay with the gut-brain axis, a vital determinant of neurological function. Disruptions in sleep patterns disturb the delicate equilibrium of the gut microbiota, resulting in dysbiosis characterized by alterations in microbial composition and function. This dysbiosis contributes to the exacerbation of neurological disorders such as depression, anxiety, and cognitive decline through multifaceted mechanisms, including heightened neuroinflammation, disturbances in neurotransmitter signalling, and compromised integrity of the gut barrier. In response to these challenges, there is a burgeoning interest in therapeutic interventions aimed at restoring gut microbial balance and alleviating neurological symptoms precipitated by sleep deprivation. Probiotics, dietary modifications, and behavioural strategies represent promising avenues for modulating the gut microbiota and mitigating the adverse effects of sleep disturbances on neurological health. Moreover, the advent of personalized interventions guided by advanced omics technologies holds considerable potential for tailoring treatments to individualized needs and optimizing therapeutic outcomes. Interdisciplinary collaboration and concerted research efforts are imperative for elucidating the underlying mechanisms linking sleep, gut microbiota, and neurological function. Longitudinal studies, translational research endeavours, and advancements in technology are pivotal for unravelling the complex interplay between these intricate systems.

Concussion and the Autonomic, Immune, and Endocrine Systems: An Introduction to the Field and a Treatment Framework for Persisting Symptoms

A significant proportion of patients who sustain a concussion/mild traumatic brain injury endorse persisting, lingering symptoms. The symptoms associated with concussion are nonspecific, and many other medical conditions present with similar symptoms. Medical conditions that overlap symptomatically with concussion include anxiety, depression, insomnia, chronic pain, chronic fatigue, fibromyalgia, and cervical strain injuries. One of the factors that may account for these similarities is that these conditions all present with disturbances in the optimal functioning of the autonomic nervous system and its intricate interactions with the endocrine system and immune system-the three primary regulatory systems in the body. When clinicians are working with patients presenting with persisting symptoms after concussion, evidence-based treatment options drawn from the literature are limited. We present a framework for the assessment and treatment of persisting symptoms following concussion based on the available evidence (treatment trials), neuroanatomical principles (research into the physiology of concussion), and clinical judgment. We review the research supporting the premise that behavioral interventions designed to stabilize and optimize regulatory systems in the body following injury have the potential to reduce symptoms and improve functioning in patients. Foundational concussion rehabilitation strategies in the areas of sleep stabilization, fatigue management, physical exercise, nutrition, relaxation protocols, and behavioral activation are outlined along with practical strategies for implementing intervention modules with patients.

A bibliometric and visual analysis of Parkinson's disease sleep disorders: articles from 2008 to 2023

Objective

Sleep disorder is a common non-motor symptom (NMS) of Parkinson's disease. However, the global research focus on Parkinson's sleep-related disorders (PDSDs) and future trends remains unclear. Currently, there is no bibliometric analysis of PDSDs. We aim to fill this gap, determine the status of current research, and predict future research hotspots.

Methods

We selected 1490 publications from the Web of Science Core Collection (WoSCC) database from 2008 to 2023. Based on CiteSpace and VOSviewer, the analysis was performed from the perspectives of the trend in the number of annual publications, countries, institutions, authors, journals, and co-citations.

Results

A total of 1490 publications from 590 authors from 409 institutions in 77 countries are included. The United States, China, and the United Kingdom are the leading countries. University College London (UCL) is the most prolific institution. Harvard University is the key for cooperation among institutions. Chaudhuri Kallol Ray is a leader in this field. "Movement Disorders" is the most influential journal. "A systematic review of the literature on disorders of sleep and wakefulness in Parkinson's disease from 2005 to 2015" is the publication with the highest co-citation intensity.

Conclusion

The total volume of publications on PDSDs is on the rise, entering a relatively high-yield stage in 2020. The COVID-19 pandemic and the emergence of new keywords may be the reasons behind this phenomenon. "quality of life" and "circadian rhythm" are the mainstream topics of PDSD research. Daytime sleepiness is the PDSD subtype that has received the most attention. Sleep quality, biomarkers, and neurodegeneration are likely to become future research hotspots.

Increased Risk for Clinically Significant Sleep Disturbances in Mild Traumatic Brain Injury: An Approach to Leveraging the Federal Interagency Traumatic Brain Injury Research Database

STUDY OBJECTIVES

The Federal Interagency Traumatic Brain Injury Research (FITBIR) Informatics System contains individual-patient-level traumatic brain injury (TBI) data, which when combined, allows for the examination of rates and outcomes for key subpopulations at risk for developing sleep disturbance.

METHODS

This proof-of-concept study creates a model system for harmonizing data (i.e., combining and standardizing data) across FITBIR studies for participants with and without a history of TBI to estimate rates of sleep disturbance and identify risk factors.

RESULTS

Three studies were eligible for harmonization (N = 1753). Sleep disturbance was common among those with a history of mild TBI (63%). Individuals with mild TBI were two to four times more likely to have sleep disturbance compared to those with no history of TBI.

CONCLUSIONS

This study established methods, harmonization code, and meta-databases that are publicly available on the FITBIR website. We demonstrated how the harmonization of FITBIR studies can answer TBI research questions, showing that associations between TBI and sleep disturbance may be influenced by demographic factors.

PPARγ activation ameliorates cognitive impairment and chronic microglial activation in the aftermath of r-mTBI

Chronic neuroinflammation and microglial activation are key mediators of the secondary injury cascades and cognitive impairment that follow exposure to repetitive mild traumatic brain injury (r-mTBI). Peroxisome proliferator-activated receptor-γ (PPARγ) is expressed on microglia and brain resident myeloid cell types and their signaling plays a major anti-inflammatory role in modulating microglial responses. At chronic timepoints following injury, constitutive PPARγ signaling is thought to be dysregulated, thus releasing the inhibitory brakes on chronically activated microglia. Increasing evidence suggests that thiazolidinediones (TZDs), a class of compounds approved from the treatment of diabetes mellitus, effectively reduce neuroinflammation and chronic microglial activation by activating the peroxisome proliferator-activated receptor-γ (PPARγ). The present study used a closed-head r-mTBI model to investigate the influence of the TZD Pioglitazone on cognitive function and neuroinflammation in the aftermath of r-mTBI exposure. We revealed that Pioglitazone treatment attenuated spatial learning and memory impairments at 6 months post-injury and reduced the expression of reactive microglia and astrocyte markers in the cortex, hippocampus, and corpus callosum. We then examined whether Pioglitazone treatment altered inflammatory signaling mechanisms in isolated microglia and confirmed downregulation of proinflammatory transcription factors and cytokine levels. To further investigate microglial-specific mechanisms underlying PPARγ-mediated neuroprotection, we generated a novel tamoxifen-inducible microglial-specific PPARγ overexpression mouse line and examined its influence on microglial phenotype following injury. Using RNA sequencing, we revealed that PPARγ overexpression ameliorates microglial activation, promotes the activation of pathways associated with wound healing and tissue repair (such as: IL10, IL4 and NGF pathways), and inhibits the adoption of a disease-associated microglia-like (DAM-like) phenotype. This study provides insight into the role of PPARγ as a critical regulator of the neuroinflammatory cascade that follows r-mTBI in mice and demonstrates that the use of PPARγ agonists such as Pioglitazone and newer generation TZDs hold strong therapeutic potential to prevent the chronic neurodegenerative sequelae of r-mTBI.

Sleep disorders and orofacial pain: insights for dental practice

In dental sleep medicine several sleep disorders commonly coexist with pain, contributing to complex clinical presentations which might affect the provision of appropriate and timely treatment. There are associations between sleep disorders and pain in general, as well as with specific orofacial pain conditions. As many as five of six patients with orofacial pain can present with sleep problems. The comorbidity of orofacial pain and sleep disorders overlays a complex web of altered neurobiological mechanisms that predispose to the chronification of orofacial pain. This review discusses the relationship between orofacial pain and sleep disorders and highlights their interactions and the neurobiological mechanisms underlying those relationships.

Silencing of LINC00707 Alleviates Brain Injury by Targeting miR-30a-5p to Regulate Microglia Inflammation and Apoptosis

The role of microglia in traumatic brain injury (TBI) has gained considerable attention. The present study aims to elucidate the potential mechanisms of Long intergenic non-protein coding RNA 707 (LINC00707) in TBI-induced microglia activation and inflammatory factor release. An in vivo model of rat TBI and in vitro microglia model was established using Controlled cortex injury (CCI) and lipopolysaccharide (LPS) stimulation. RT-qPCR to detect LINC00707 levels in rat cerebral cortex or cells. Modified Neurological Impairment Score (mNSS) and Morris Water Maze test was conducted to assess the neurological deficits and cognitive impairment. ELISA analysis of pro-inflammatory factors levels. CCK-8 and flow cytometry for cell viability and apoptosis levels. Dual-luciferase report and RIP assay to validate the targeting relationship between LINC00707 and miR-30a-5p. LINC00707 was elevated in the TBI rat cerebral cortex and LPS-induced microglia, while miR-30a-5p was noticeably decreased (P < 0.05). Increased mNSS, cognitive dysfunction, and brain edema in TBI rats were all prominently reversed by silencing of LINC00707, but this reversal was partially abrogated by decreasing miR-30a-5p (P < 0.05). Inhibition of LINC00707 suppressed the overproduction of inflammatory factors in TBI rats (P < 0.05). LPS decreased microglial cell viability, increased apoptosis, and promoted inflammatory overproduction than control, but the silencing of LINC00707 reversed its effect. Suppression of miR-30a-5p attenuated this reversal (P < 0.05). miR-30a-5p was the target miRNA of LINC00707. All in all, the results suggested that inhibiting LINC00707/miR-30a-5p axis could alleviate the progression of TBI by suppressing the inflammation and apoptosis of microglia cells.

Thirty Risk Factors for Alzheimer's Disease Unified by a Common Neuroimmune-Neuroinflammation Mechanism

One of the major obstacles confronting the formulation of a mechanistic understanding for Alzheimer's disease (AD) is its immense complexity-a complexity that traverses the full structural and phenomenological spectrum, including molecular, macromolecular, cellular, neurological and behavioural processes. This complexity is reflected by the equally complex diversity of risk factors associated with AD. However, more than merely mirroring disease complexity, risk factors also provide fundamental insights into the aetiology and pathogenesis of AD as a neurodegenerative disorder since they are central to disease initiation and subsequent propagation. Based on a systematic literature assessment, this review identified 30 risk factors for AD and then extended the analysis to further identify neuroinflammation as a unifying mechanism present in all 30 risk factors. Although other mechanisms (e.g., vasculopathy, proteopathy) were present in multiple risk factors, dysfunction of the neuroimmune-neuroinflammation axis was uniquely central to all 30 identified risk factors. Though the nature of the neuroinflammatory involvement varied, the activation of microglia and the release of pro-inflammatory cytokines were a common pathway shared by all risk factors. This observation provides further evidence for the importance of immunopathic mechanisms in the aetiopathogenesis of AD.

Neurosteroid Receptor Modulators for Treating Traumatic Brain Injury

Traumatic brain injury (TBI) triggers wide-ranging pathology that impacts multiple biochemical and physiological systems, both inside and outside the brain. Functional recovery in patients is impeded by early onset brain edema, acute and chronic inflammation, delayed cell death, and neurovascular disruption. Drug treatments that target these deficits are under active development, but it seems likely that fully effective therapy may require interruption of the multiplicity of TBI-induced pathological processes either by a cocktail of drug treatments or a single pleiotropic drug. The complex and highly interconnected biochemical network embodied by the neurosteroid system offers multiple options for the research and development of pleiotropic drug treatments that may provide benefit for those who have suffered a TBI. This narrative review examines the neurosteroids and their signaling systems and proposes directions for their utility in the next stage of TBI drug research and development.

Sleep Disorders Associated with Neurodegenerative Diseases

Sleep disturbances are common in various neurological pathologies, including amyotrophic lateral sclerosis (ALS), multiple system atrophy (MSA), hereditary ataxias, Huntington's disease (HD), progressive supranuclear palsy (PSP), and dementia with Lewy bodies (DLB). This article reviews the prevalence and characteristics of sleep disorders in these conditions, highlighting their impact on patients' quality of life and disease progression. Sleep-related breathing disorders, insomnia, restless legs syndrome (RLS), periodic limb movement syndrome (PLMS), and rapid eye movement sleep behavior disorder (RBD) are among the common sleep disturbances reported. Both pharmacological and non-pharmacological interventions play crucial roles in managing sleep disturbances and enhancing overall patient care.

Circadian therapy interventions for glymphatic dysfunction in concussions injuries: A narrative review

There are two primary threats to the brain after concussion. The first is a buildup of neurotoxic proteins in the brain. The second, a partial consequence of the first, is a sustained neuroinflammatory response that may lead to central sensitization and the development of persistent post-concussive symptoms. These threats make neurotoxin clearance a high clinical priority in the acute period after injury. The glymphatic system is the brain's primary mechanism for clearing neurotoxic waste. The glymphatic system is intimately tied to the sleep cycle and circadian dynamics. However, glymphatic dysfunction and sleep disturbances are nearly ubiquitous in the acute period after concussion injury. Because of this, sleep optimization via circadian therapy is a time-sensitive and critical tool in acute concussion management.

Prevalence and risk factors of significant persistent pain symptoms after critical care illness: a prospective multicentric study

BACKGROUND

Prevalence, risk factors and medical management of persistent pain symptoms after critical care illness have not been thoroughly investigated.

METHODS

We performed a prospective multicentric study in patients with an intensive care unit (ICU) length of stay ≥ 48 h. The primary outcome was the prevalence of significant persistent pain, defined as a numeric rating scale (NRS) ≥ 3, 3 months after admission. Secondary outcomes were the prevalence of symptoms compatible with neuropathic pain (ID-pain score > 3) and the risk factors of persistent pain.

RESULTS

Eight hundred fourteen patients were included over a 10-month period in 26 centers. Patients had a mean age of 57 (± 17) years with a SAPS 2 score of 32 (± 16) (mean ± SD). The median ICU length of stay was 6 [4-12] days (median [interquartile]). At 3 months, the median intensity of pain symptoms was 2 [1-5] in the entire population, and 388 (47.7%) patients had significant pain. In this group, 34 (8.7%) patients had symptoms compatible with neuropathic pain. Female (Odds Ratio 1.5 95% CI [1.1-2.1]), prior use of anti-depressive agents (OR 2.2 95% CI [1.3-4]), prone positioning (OR 3 95% CI [1.4-6.4]) and the presence of pain symptoms on ICU discharge (NRS ≥ 3) (OR 2.4 95% CI [1.7-3.4]) were risk factors of persistent pain. Compared with sepsis, patients admitted for trauma (non neuro) (OR 3.5 95% CI [2.1-6]) were particularly at risk of persistent pain. Only 35 (11.3%) patients had specialist pain management by 3 months.

CONCLUSIONS

Persistent pain symptoms were frequent in critical illness survivors and specialized management remained infrequent. Innovative approaches must be developed in the ICU to minimize the consequences of pain.

TRIAL REGISTRATION

NCT04817696. Registered March 26, 2021.

The Effect of Craniofacial Manual Lymphatic Drainage after Moderate Traumatic Brain Injury

Previous studies suggest that craniofacial manual lymphatic drainage (MLD) facilitates brain fluids clearance, reducing intracranial pressure and reabsorbing chronic subdural hematoma. This study aimed to explore the effect of craniofacial MLD in combination with pharmacological treatment for improving cranial pain intensity, vital signs, and cerebral edema (Hounsfield units, HUs) in moderate traumatic brain injury (mTBI). Patient 1 received pharmacological therapy, while patient 2 received both pharmacological and craniocervical MLD treatment. Patient 2 showed decreased cranial pain intensity and systolic blood pressure (66%-11.11%, respectively) after two 30 min daily sessions of treatment for three days. HUs in the caudate nucleus of both hemispheres (left 24.64%-right 28.72%) and in the left temporal cortical gray matter increased (17.8%). An increase in HU suggests a reduction in cerebral edema and vice versa. For patient 1, there were no changes in cranial pain intensity, but a slight increase in the systolic blood pressure was observed (0%-3.27%, respectively). HUs decreased in the temporal cortical (14.98%) and caudate nucleus gray matter (9.77%) of the left and right cerebral hemispheres (11.96%-16.74%, respectively). This case study suggests that craniofacial MLD combined with pharmacological treatment could reduce cerebral edema, decrease head pain intensity, and maintain vital signs in normal physiologic values in patients with mTBI.