Blood-Brain Barrier Dysfunction Predicts Microglial Activation After Traumatic Brain Injury in Juvenile Rats.

Traumatic brain injury (TBI) disrupts the blood-brain barrier (BBB), which may exacerbate neuroinflammation post-injury. Few translational studies have examined BBB dysfunction and subsequent neuroinflammation post-TBI in juveniles. We hypothesized that BBB dysfunction positively predicts microglial activation and that vulnerability to BBB dysfunction and associated neuroinflammation are dependent on age at injury. Post-natal day (PND)17 and PND35 rats (n = 56) received midline fluid percussion injury or sham surgery, and immunoglobulin-G (IgG) stain was quantified as a marker of extravasated blood in the brain and BBB dysfunction. We investigated BBB dysfunction and the microglial response in the hippocampus, hypothalamus, and motor cortex relative to age at injury and days post-injury (DPI; 1, 7, and 25). We measured the morphologies of ionized calcium-binding adaptor molecule 1-labeled microglia using cell body area and perimeter, microglial branch number and length, end-points/microglial cell, and number of microglia. Data were analyzed using generalized hierarchical models. In PND17 rats, TBI increased levels of IgG compared to shams. Independent of age at injury, IgG in TBI rats was higher at 1 and 7 DPI, but resolved by 25 DPI. TBI activated microglia (more cells and fewer end-points) in PND35 rats compared to respective shams. Independent of age at injury, TBI induced morphological changes indicative of microglial activation, which resolved by 25 DPI. TBI rats had fewer cells and end-points per cell at 1 and 7 DPI than 25 DPI. Independent of TBI, PND17 rats had larger, more activated microglia than PND35 rats; PND17 TBI rats had larger cell body areas and perimeters than PND35 TBI rats. Importantly, we found support in both ages that IgG quantification predicted microglial activation after TBI. The number of microglia increased with increasing IgG, whereas branch length decreased with increasing IgG, which together indicate microglial activation. Our results suggest that stabilization of the BBB after pediatric TBI may be an important therapeutic strategy to limit neuroinflammation and promote recovery.

Postpartum haemorrhage occurring in UK midwifery units: A national population-based case-control study to investigate incidence, risk factors and outcomes.

OBJECTIVES: To estimate the incidence of, and investigate risk factors for, postpartum haemorrhage (PPH) requiring transfer to obstetric care following birth in midwifery units (MU) in the UK; to describe outcomes for women who experience PPH requiring transfer to obstetric care. METHODS: We conducted a national population-based case-control study in all MUs in the UK using the UK Midwifery Study System (UKMidSS). Between September 2019 and February 2020, 1501 women with PPH requiring transfer to obstetric care following birth in an MU, and 1475 control women were identified. We used multivariable logistic regression, generating adjusted odds ratios (aORs) and 95% confidence intervals (CIs) to investigate risk factors for PPH requiring transfer to obstetric care. RESULTS: The incidence of PPH requiring transfer to obstetric care following birth in an MU was 3.7% (95% CI 3.6%-3.9%). Factors independently associated with PPH requiring transfer to obstetric care were smoking during pregnancy (aOR = 0.73; 95% CI 0.56-0.94), nulliparity (aOR = 1.96; 95% CI 1.66-2.30), previous PPH (aOR = 2.67; 95% CI 1.67-4.25), complications in a previous pregnancy other than PPH (aOR = 2.40; 95% CI 1.25-4.60), gestational age ≥41 weeks (aOR = 1.36; 95% CI 1.10-1.69), instrumental birth (aOR = 2.69; 95% CI 1.53-4.72), third stage of labour ≥60 minutes (aOR = 5.56; 95% CI 3.93-7.88), perineal trauma (aOR = 4.67; 95% CI 3.16-6.90), and birthweight 3500-3999g (aOR = 1.71; 95% CI 1.42-2.07) or ≥4000g (aOR = 2.31; 95% CI 1.78-3.00). One in ten (10.6%) cases received a blood transfusion and one in five (21.0%) were admitted to higher level care. CONCLUSIONS: The risk factors identified in this study align with those identified in previous research and with current guidelines for women planning birth in an MU in the UK. Maternal outcomes after PPH were broadly reassuring and indicative of appropriate management. NHS organisations should ensure that robust guidelines are in place to support management of PPH in MUs.

Colony-Stimulating Factor-1 Receptor Inhibition Transiently Attenuated the Peripheral Immune Response to Experimental Traumatic Brain Injury.

To investigate microglial mechanisms in central and peripheral inflammation after experimental traumatic brain injury (TBI), we inhibited the colony-stimulating factor-1 receptor (CSF-1R) with PLX5622 (PLX). We hypothesized that microglia depletion would attenuate central inflammation acutely with no effect on peripheral inflammation. After randomization, male mice (n = 105) were fed PLX or control diets (21 days) and then received midline fluid percussion injury or sham injury. Brain and blood were collected at 1, 3, or 7 days post-injury (DPI). Immune cell populations were quantified in the brain and blood by flow cytometry. Cytokines (interleukin [IL]-6, IL-1ß, tumor necrosis factor-α, interferon-γ, IL-17A, and IL-10) were quantified in the blood using a multi-plex enzyme-linked immunosorbent assay. Data were analyzed using Bayesian multi-variate, multi-level models. PLX depleted microglia at all time points and reduced neutrophils in the brain at 7 DPI. PLX also depleted CD115+ monocytes, reduced myeloid cells, neutrophils, and Ly6Clow monocytes in blood, and elevated IL-6. TBI induced a central and peripheral immune response. TBI elevated leukocytes, microglia, and macrophages in the brain and elevated peripheral myeloid cells, neutrophils, Ly6Cint monocytes, and IL-1ß in the blood. TBI lowered peripheral CD115+ and Ly6Clow monocytes in the blood. TBI PLX mice had fewer leukocytes and microglia in the brain at 1 DPI, with elevated neutrophils at 7 DPI compared to TBI mice on a control diet. TBI PLX mice also had fewer peripheral myeloid cells, CD115+, and Ly6Clow monocytes in the blood at 3 DPI, but elevated Ly6Chigh, Ly6Cint, and CD115+ monocyte populations at 7 DPI, compared to TBI mice on a control diet. TBI PLX mice had elevated proinflammatory cytokines and lower anti-inflammatory cytokines in the blood at 7 DPI compared to TBI mice on a control diet. CSF-1R inhibition reduced the immune response to TBI at 1 and 3 DPI, but elevated peripheral inflammation at 7 DPI.

Outcomes for women admitted for labour care to alongside midwifery units in the UK following a postpartum haemorrhage in a previous pregnancy: A national population-based cohort and nested case-control study using the UK Midwifery Study System (UKMidSS).

BACKGROUND: Women who have experienced a postpartum haemorrhage (PPH) 'requiring treatment or transfusion' are typically advised to plan birth in obstetric-led settings in subsequent pregnancies. Many UK alongside midwifery units (AMU) admit women for labour care following a previous PPH. We aimed to describe outcomes in women admitted for labour care to AMUs following a previous PPH, compare outcomes with other multiparous women admitted to the same AMUs, and explore risk factors for recurrence. METHODS: A national cohort and nested case-control study using the UK Midwifery Study System (UKMidSS), between August 2018 and April 2019. Multivariable Poisson regression and logistic regression were performed to compare outcomes and investigate risk factors for recurrence. FINDINGS: Women who experienced a previous PPH were significantly more likely than comparison women to: have a PPH requiring transfer to obstetric care (4·2% vs. 2·4%, aRR=1·65, 95% CI 1·14-2·38), be transferred to obstetric care for any reason (17·8% vs 11·9%; aRR=1·41; 95% CI 1·09-1·83), and have any PPH≥ 500 ml (22·7% vs 11·1%, aRR=1·86, 95% CI 1·49-2·32). Among women with a previous PPH, previous blood loss > 1500 ml; uterotonics for previous PPH; Caesarean associated with previous PPH; gestation at admission and higher birthweight were independent risk factors for PPH. CONCLUSION: Women considering birth in an AMU after a previous PPH should be advised that they are at increased risk of experiencing a subsequent PPH requiring transfer to obstetric care, compared with other multiparous women who have not had a PPH. The absolute risk of a subsequent PPH in this group is low and comparable to the overall risk of having a PPH among women having a spontaneous vaginal birth in England.

Reactive morphology of dividing microglia following kainic acid administration.

The microglial response to a pathological microenvironment is hallmarked by a change in cellular morphology. Following a pathological stimulus, microglia become reactive and simultaneously divide to create daughter cells. Although a wide array of microglial morphologies has been observed, the exact functions of these distinct morphologies are unknown, as are the morphology and reactivity status of dividing microglia. In this study, we used kainic acid to trigger microglial activation and cell division. Following a cortical kainic acid injection, microglial morphology and proliferation were examined at 3 days post-injection using immunohistochemistry for ionized calcium binding adapter molecule 1 (Iba1) to stain for microglia, and KI67 as a marker of cell division. Individual microglial cells were isolated from photomicrographs and skeletal and fractal analyses were used to examine cell size and spatial complexity. We examined the morphology of microglia in both wildtype and microglia-specific tumor necrosis factor (TNF)-α knockout mice. Data were analyzed using generalized linear mixed models or a two-way ANOVA. We found that dividing microglia had a more reactive morphology (larger cell body area, longer cell perimeter, and less ramification) compared to microglia that were not dividing, regardless of microglial release of TNF-α. However, we also observed dividing microglia with a complex, more ramified morphology. Changes in microglial morphology and division were greatest near the kainic acid injection site. This study uses robust and quantitative techniques to better understand microglial cell division, morphology, and population dynamics, which are essential for the development of novel therapeutics that target microglia.

Design and Synthesis of Brain Penetrant Glycopeptide Analogues of PACAP With Neuroprotective Potential for Traumatic Brain Injury and Parkinsonism.

There is an unmet clinical need for curative therapies to treat neurodegenerative disorders. Most mainstay treatments currently on the market only alleviate specific symptoms and do not reverse disease progression. The Pituitary adenylate cyclase-activating polypeptide (PACAP), an endogenous neuropeptide hormone, has been extensively studied as a potential regenerative therapeutic. PACAP is widely distributed in the central nervous system (CNS) and exerts its neuroprotective and neurotrophic effects via the related Class B GPCRs PAC1, VPAC1, and VPAC2, at which the hormone shows roughly equal activity. Vasoactive intestinal peptide (VIP) also activates these receptors, and this close analogue of PACAP has also shown to promote neuronal survival in various animal models of acute and progressive neurodegenerative diseases. However, PACAP's poor pharmacokinetic profile (non-linear PK/PD), and more importantly its limited blood-brain barrier (BBB) permeability has hampered development of this peptide as a therapeutic. We have demonstrated that glycosylation of PACAP and related peptides promotes penetration of the BBB and improves PK properties while retaining efficacy and potency in the low nanomolar range at its target receptors. Furthermore, judicious structure-activity relationship (SAR) studies revealed key motifs that can be modulated to afford compounds with diverse selectivity profiles. Most importantly, we have demonstrated that select PACAP glycopeptide analogues (2LS80Mel and 2LS98Lac) exert potent neuroprotective effects and anti-inflammatory activity in animal models of traumatic brain injury and in a mild-toxin lesion model of Parkinson's disease, highlighting glycosylation as a viable strategy for converting endogenous peptides into robust and efficacious drug candidates.

Tobacco cessation experiences and needs: perspectives from Arabic-speaking communities.

Use of tobacco products is higher in Arabic-speaking communities in Australia, compared to other populations. 70 persons identifying as being from Arabic-speaking communities in Western Sydney participated in focus group discussions to explore experiences and needs relating to tobacco, alcohol and other drug treatment. Tobacco was rated as the substance of highest concern in this sample, however a pattern of change was observed. Widespread cigarette use supported by gendered norms that particularly encouraged smoking among men was shifting, with some decline in the social acceptability of cigarette smoking linked to experience of health impacts and the financial cost to families. In contrast, waterpipe tobacco smoking was described as a common and acceptable practice across age and gender cohorts, despite some participants challenging the cultural and health rationales of this practice. Preventing tobacco-related harm among younger populations was highly valued among study participants, drawing on strong support for families as key influencer of health behaviors. Cessation strategies viewed as effective among community members spoken with commonly centered upon the notion of individual willpower, and appreciated the disincentivising impacts of high taxation on cigarettes. This study prioritizes community-informed perspectives for reducing tobacco related harms amongst Arabic-speaking populations in Australia and offers direction to health promoters, public health workers and policymakers. Results indicate opportunities exist to improve tobacco control outcomes through strategies that align prevention and treatment options with relevant community beliefs and norms, and build on existing harm reduction behaviors and support seeking behaviors.

Age-At-Injury Influences the Glial Response to Traumatic Brain Injury in the Cortex of Male Juvenile Rats.

Few translational studies have examined how age-at-injury affects the glial response to traumatic brain injury (TBI). We hypothesized that rats injured at post-natal day (PND) 17 would exhibit a greater glial response, that would persist into early adulthood, compared to rats injured at PND35. PND17 and PND35 rats (n = 75) received a mild to moderate midline fluid percussion injury or sham surgery. In three cortical regions [peri-injury, primary somatosensory barrel field (S1BF), perirhinal], we investigated the glial response relative to age-at-injury (PND17 or PND35), time post-injury (2 hours, 1 day, 7 days, 25 days, or 43 days), and post-natal age, such that rats injured at PND17 or PND35 were compared at the same post-natal-age (e.g., PND17 + 25D post-injury = PND42; PND35 + 7D post-injury = PND42). We measured Iba1 positive microglia cells (area, perimeter) and quantified their activation status using skeletal analysis (branch length/cell, mean processes/cell, cell abundance). GFAP expression was examined using immunohistochemistry and pixel analysis. Data were analyzed using Bayesian multivariate multi-level models. Independent of age-at-injury, TBI activated microglia (shorter branches, fewer processes) in the S1BF and perirhinal cortex with more microglia in all regions compared to uninjured shams. TBI-induced microglial activation (shorter branches) was sustained in the S1BF into early adulthood (PND60). Overall, PND17 injured rats had more microglial activation in the perirhinal cortex than PND35 injured rats. Activation was not confounded by age-dependent cell size changes, and microglial cell body sizes were similar between PND17 and PND35 rats. There were no differences in astrocyte GFAP expression. Increased microglial activation in PND17 brain-injured rats suggests that TBI upregulates the glial response at discrete stages of development. Age-at-injury and aging with an injury are translationally important because experiencing a TBI at an early age may trigger an exaggerated glial response.

Neonatal admission and mortality in babies born in UK alongside midwifery units: a national population-based case-control study using the UK Midwifery Study System (UKMidSS).

OBJECTIVES: To determine the incidence of and risk factors for neonatal unit admission, intrapartum stillbirth or neonatal death without admission, and describe outcomes, in babies born in an alongside midwifery unit (AMU). DESIGN: National population-based case-control study. METHOD: We used the UK Midwifery Study System to identify and collect data about 1041 women who gave birth in AMUs, March 2017 to February 2018, whose babies were admitted to a neonatal unit or died (cases) and 1984 controls from the same AMUs. We used multivariable logistic regression, generating adjusted OR (aOR) with 95% CIs, to investigate maternal and intrapartum factors associated with neonatal admission or mortality. RESULTS: The incidence of neonatal admission or mortality following birth in an AMU was 1.2%, comprising neonatal admission (1.2%) and mortality (0.01%). White 'other' ethnicity (aOR=1.28; 95% CI=1.01 to 1.63); nulliparity (aOR=2.09; 95% CI=1.78 to 2.45); ≥2 previous pregnancies ≥24 weeks' gestation (aOR=1.38; 95% CI=1.10 to 1.74); male sex (aOR=1.46; 95% CI=1.23 to 1.75); maternal pregnancy problem (aOR=1.40; 95% CI=1.03 to 1.90); prolonged (aOR=1.42; 95% CI=1.01 to 2.01) or unrecorded (aOR=1.38; 95% CI=1.05 to 1.81) second stage duration; opiate use (aOR=1.31; 95% CI=1.02 to 1.68); shoulder dystocia (aOR=5.06; 95% CI=3.00 to 8.52); birth weight <2500 g (aOR=4.12; 95% CI=1.97 to 8.60), 4000-4999 g (aOR=1.64; 95% CI=1.25 to 2.14) and ≥4500 g (aOR=2.10; 95% CI=1.17 to 3.76), were independently associated with neonatal admission or mortality. Among babies admitted (n=1038), 18% received intensive care. Nine babies died, six following neonatal admission. Sepsis (52%) and respiratory distress (42%) were the most common discharge diagnoses. CONCLUSIONS: The results of this study are in line with other evidence on risk factors for neonatal admission, and reassuring in terms of the quality and safety of care in AMUs.

Evaluating abusive head trauma in children <5 years old: Risk factors and the importance of the social history.

BACKGROUND: Abusive head trauma (AHT) is the leading cause traumatic death in children ≤5 years of age. AHT remains seriously under-surveilled, increasing the risk of subsequent injury and death. This study assesses the clinical and social risks associated with fatal and non-fatal AHT. METHODS: A single-institution, retrospective review of suspected AHT patients ≤5 years of age between 2010 and 2016 using a prospective hospital forensic registry data yielded demographic, clinical, family, psycho-social and other follow-up information. Descriptive statistics were used to look for differences between patients with AHT and accidental head trauma. Logistic regression estimated the adjusted odds ratios (AOR) for AHT. A receiver operating characteristic (ROC) curve was created to calculate model sensitivity and specificity. RESULTS: Forensic evaluations of 783 children age ≤5 years with head trauma met the inclusion criteria; 25 were fatal with median[IQR] age 23[4.5-39.0] months. Of 758 non-fatal patients, age was 7[3.0-11.0] months; 59.5% male; 435 patients (57.4%) presented with a skull fracture, 403 (53.2%) with intracranial hemorrhage. Ultimately 242 (31.9%) were adjudicated AHT, 335(44.2%) were accidental, 181 (23.9%) were undetermined. Clinical factors increasing the risk of AHT included multiple fractures (Exp(ß) = 9.9[p = 0.001]), bruising (Expß = 5.7[p < 0.001]), subdural blood (Exp(ß) = 5.3[p = 0.001]), seizures (Exp(ß) = 4.9[p = 0.02]), lethargy/unresponsiveness (Exp(ß) = 2.24[p = 0.02]), loss of consciousness (Exp(ß) = 4.69[p = 0.001]), and unknown mechanism of injury (Exp(ß) = 3.9[p = 0.001]); skull fracture reduced the risk of AHT by half (Exp(ß) = 0.5[p = 0.011]). Social risks factors included prior police involvement (Exp(ß) = 5.9[p = 0.001]), substance abuse (Exp(ß) = 5.7[p = .001]), unknown number of adults in the home (Exp(ß) = 4.1[p = 0.001]) and intimate partner violence (Exp(ß) = 2.3[p = 0.02]). ROC area under the curve (AUC) = 0.90([95% CI = 0.86-0.93] p = .001) provides 73% sensitivity; 91% specificity. CONCLUSIONS: To improve surveillance of AHT, interviews should include and consider social factors including caregiver/household substance abuse, intimate partner violence, prior police involvement and household size. An unknown number of adults in home is associated with an increased risk of AHT. STUDY TYPE/LEVEL OF EVIDENCE: Prognostic, Level III.

Sex-Dependent Pathology in the HPA Axis at a Sub-acute Period After Experimental Traumatic Brain Injury.

Over 2.8 million traumatic brain injuries (TBIs) are reported in the United States annually, of which, over 75% are mild TBIs with diffuse axonal injury (DAI) as the primary pathology. TBI instigates a stress response that stimulates the hypothalamic-pituitary-adrenal (HPA) axis concurrently with DAI in brain regions responsible for feedback regulation. While the incidence of affective symptoms is high in both men and women, presentation is more prevalent and severe in women. Few studies have longitudinally evaluated the etiology underlying late-onset affective symptoms after mild TBI and even fewer have included females in the experimental design. In the experimental TBI model employed in this study, evidence of chronic HPA dysregulation has been reported at 2 months post-injury in male rats, with peak neuropathology in other regions of the brain at 7 days post-injury (DPI). We predicted that mechanisms leading to dysregulation of the HPA axis in male and female rats would be most evident at 7 DPI, the sub-acute time point. Young adult age-matched male and naturally cycling female Sprague Dawley rats were subjected to midline fluid percussion injury (mFPI) or sham surgery. Corticotropin releasing hormone, gliosis, and glucocorticoid receptor (GR) levels were evaluated in the hypothalamus and hippocampus, along with baseline plasma adrenocorticotropic hormone (ACTH) and adrenal gland weights. Microglial response in the paraventricular nucleus of the hypothalamus indicated mild neuroinflammation in males compared to sex-matched shams, but not females. Evidence of microglia activation in the dentate gyrus of the hippocampus was robust in both sexes compared with uninjured shams and there was evidence of a significant interaction between sex and injury regarding microglial cell count. GFAP intensity and astrocyte numbers increased as a function of injury, indicative of astrocytosis. GR protein levels were elevated 30% in the hippocampus of females in comparison to sex-matched shams. These data indicate sex-differences in sub-acute pathophysiology following DAI that precede late-onset HPA axis dysregulation. Further understanding of the etiology leading up to late-onset HPA axis dysregulation following DAI could identify targets to stabilize feedback, attenuate symptoms, and improve efficacy of rehabilitation and overall recovery.

What is the alcohol, tobacco, and other drug prevalence among culturally and linguistically diverse groups in the Australian population? A national study of prevalence, harms, and attitudes.

In Australia, one in three people are born overseas, and one in five households speak languages other than English. This study explores substance use prevalence, related harms, and attitudes among these large groups in the population. Analysis was conducted using cross-sectional data (N = 22, 696) from the 2013 National Drug Strategy Household Survey. General linear model and binary logistic regression were used to assess substance use and harms, using stabilized inverse propensity score weighting to control for potential confounding variables. Between culturally and linguistically diverse populations and the population born in Australia, United Kingdom, or New Zealand who speak only English at home, there is no statistically significant variation in the likelihood of current smoking; using analgesics, tranquilizers, or sleeping pills; or administering drugs via injection. Culturally diverse populations are less likely to drink alcohol or use cannabis or methamphetamines. No difference between these two major groups in the population is observed in substance-related abuse from strangers; but culturally diverse respondents are less likely to report substance-related abuse from known persons. Lower substance use prevalence is not observed among people from culturally diverse backgrounds who have mental health issues. Australian-, UK-, or New Zealand-born respondents who speak only English at home are more likely to oppose drug and tobacco policies, including a range of harm reduction policies. We discuss the practical and ethical limitations of this major Australian data set for examining the burden of drug-related harms experienced by specific migrant populations. Avenues for potential future research are outlined.

Mild and Moderate Traumatic Brain Injury and Repeated Stress Affect Corticosterone in the Rat.

Traumatic brain injury (TBI) survivors suffer from a range of morbidities, including post-traumatic endocrinopathies that can cause physical and mental changes in patients, greatly compromising quality of life. This study tested the hypothesis that mild and moderate diffuse TBI leads to chronic deficiencies in corticosterone (CORT) regulation following repeated exposure to restraint stress over time. Young adult male rats (n = 9-11/group) were subjected to mild or moderate TBI induced by midline fluid percussion injury (mFPI) or control sham surgery. At 6 and 24 h post-injury, both mild and moderate TBI resulted in elevated resting plasma CORT levels compared with uninjured shams. Independent of TBI severity, all rats had lower resting plasma CORT levels at 7, 14, 28, and 54 days post-injury compared with pre-surgery baseline CORT. Circulating levels of CORT were also evaluated under restraint stress and in response to dexamethasone (DEX), a synthetic glucocorticoid. Independent of TBI severity, restraint stress elevated CORT at 30, 60, and 90 min post-stressor initiation at all post-injury time-points. A blunted CORT response to restraint stress was observed with lower CORT levels after restraint at 28 and 54 days compared with 7 days post-injury (DPI), indicative of habituation to the stressor. A high dose of DEX lowered CORT levels at 90 min post-restraint stress initiation compared with low-dose DEX, independent of TBI severity. These results support TBI-induced CORT dysregulation at acute time-points, but additional studies that investigate the onset and progression of endocrinopathies, controlling for habituation to repeated restraint stress, are needed to inform the diagnosis and treatment of such morbidities in TBI survivors.

Traumatic brain injury-induced neuronal damage in the somatosensory cortex causes formation of rod-shaped microglia that promote astrogliosis and persistent neuroinflammation.

Microglia undergo dynamic structural and transcriptional changes during the immune response to traumatic brain injury (TBI). For example, TBI causes microglia to form rod-shaped trains in the cerebral cortex, but their contribution to inflammation and pathophysiology is unclear. The purpose of this study was to determine the origin and alignment of rod microglia and to determine the role of microglia in propagating persistent cortical inflammation. Here, diffuse TBI in mice was modeled by midline fluid percussion injury (FPI). Bone marrow chimerism and BrdU pulse-chase experiments revealed that rod microglia derived from resident microglia with limited proliferation. Novel data also show that TBI-induced rod microglia were proximal to axotomized neurons, spatially overlapped with dense astrogliosis, and aligned with apical pyramidal dendrites. Furthermore, rod microglia formed adjacent to hypertrophied microglia, which clustered among layer V pyramidal neurons. To better understand the contribution of microglia to cortical inflammation and injury, microglia were eliminated prior to TBI by CSF1R antagonism (PLX5622). Microglial elimination did not affect cortical neuron axotomy induced by TBI, but attenuated rod microglial formation and astrogliosis. Analysis of 262 immune genes revealed that TBI caused profound cortical inflammation acutely (8 hr) that progressed in nature and complexity by 7 dpi. For instance, gene expression related to complement, phagocytosis, toll-like receptor signaling, and interferon response were increased 7 dpi. Critically, these acute and chronic inflammatory responses were prevented by microglial elimination. Taken together, TBI-induced neuronal injury causes microglia to structurally associate with neurons, augment astrogliosis, and propagate diverse and persistent inflammatory/immune signaling pathways.

Novel TNF receptor-1 inhibitors identified as potential therapeutic candidates for traumatic brain injury.

BACKGROUND: Traumatic brain injury (TBI) begins with the application of mechanical force to the head or brain, which initiates systemic and cellular processes that are hallmarks of the disease. The pathological cascade of secondary injury processes, including inflammation, can exacerbate brain injury-induced morbidities and thus represents a plausible target for pharmaceutical therapies. We have pioneered research on post-traumatic sleep, identifying that injury-induced sleep lasting for 6 h in brain-injured mice coincides with increased cortical levels of inflammatory cytokines, including tumor necrosis factor (TNF). Here, we apply post-traumatic sleep as a physiological bio-indicator of inflammation. We hypothesized the efficacy of novel TNF receptor (TNF-R) inhibitors could be screened using post-traumatic sleep and that these novel compounds would improve functional recovery following diffuse TBI in the mouse. METHODS: Three inhibitors of TNF-R activation were synthesized based on the structure of previously reported TNF CIAM inhibitor F002, which lodges into a defined TNFR1 cavity at the TNF-binding interface, and screened for in vitro efficacy of TNF pathway inhibition (IκB phosphorylation). Compounds were screened for in vivo efficacy in modulating post-traumatic sleep. Compounds were then tested for efficacy in improving functional recovery and verification of cellular mechanism. RESULTS: Brain-injured mice treated with Compound 7 (C7) or SGT11 slept significantly less than those treated with vehicle, suggesting a therapeutic potential to target neuroinflammation. SGT11 restored cognitive, sensorimotor, and neurological function. C7 and SGT11 significantly decreased cortical inflammatory cytokines 3 h post-TBI. CONCLUSIONS: Using sleep as a bio-indicator of TNF-R-dependent neuroinflammation, we identified C7 and SGT11 as potential therapeutic candidates for TBI.

Diffuse traumatic brain injury induces prolonged immune dysregulation and potentiates hyperalgesia following a peripheral immune challenge.

BACKGROUND: Nociceptive and neuropathic pain occurs as part of the disease process after traumatic brain injury (TBI) in humans. Central and peripheral inflammation, a major secondary injury process initiated by the traumatic brain injury event, has been implicated in the potentiation of peripheral nociceptive pain. We hypothesized that the inflammatory response to diffuse traumatic brain injury potentiates persistent pain through prolonged immune dysregulation. RESULTS: To test this, adult, male C57BL/6 mice were subjected to midline fluid percussion brain injury or to sham procedure. One cohort of mice was analyzed for inflammation-related cytokine levels in cortical biopsies and serum along an acute time course. In a second cohort, peripheral inflammation was induced seven days after surgery/injury with an intraplantar injection of carrageenan. This was followed by measurement of mechanical hyperalgesia, glial fibrillary acidic protein and Iba1 immunohistochemical analysis of neuroinflammation in the brain, and flow cytometric analysis of T-cell differentiation in mucosal lymph. Traumatic brain injury increased interleukin-6 and chemokine ligand 1 levels in the cortex and serum that peaked within 1-9 h and then resolved. Intraplantar carrageenan produced mechanical hyperalgesia that was potentiated by traumatic brain injury. Further, mucosal T cells from brain-injured mice showed a distinct deficiency in the ability to differentiate into inflammation-suppressing regulatory T cells (Tregs). CONCLUSIONS: We conclude that traumatic brain injury increased the inflammatory pain associated with cutaneous inflammation by contributing to systemic immune dysregulation. Regulatory T cells are immune suppressors and failure of T cells to differentiate into regulatory T cells leads to unregulated cytokine production which may contribute to the potentiation of peripheral pain through the excitation of peripheral sensory neurons. In addition, regulatory T cells are identified as a potential target for therapeutic rebalancing of peripheral immune homeostasis to improve functional outcome and decrease the incidence of peripheral inflammatory pain following traumatic brain injury.

The p38α MAPK regulates microglial responsiveness to diffuse traumatic brain injury.

Neuropathology after traumatic brain injury (TBI) is the result of both the immediate impact injury and secondary injury mechanisms. Unresolved post-traumatic glial activation is a secondary injury mechanism that contributes to a chronic state of neuroinflammation in both animal models of TBI and human head injury patients. We recently demonstrated, using in vitro models, that p38α MAPK signaling in microglia is a key event in promoting cytokine production in response to diverse disease-relevant stressors and subsequent inflammatory neuronal dysfunction. From these findings, we hypothesized that the p38α signaling pathway in microglia could be contributing to the secondary neuropathologic sequelae after a diffuse TBI. Mice where microglia were p38α-deficient (p38α KO) were protected against TBI-induced motor deficits and synaptic protein loss. In wild-type (WT) mice, diffuse TBI produced microglia morphological activation that lasted for at least 7 d; however, p38α KO mice failed to activate this response. Unexpectedly, we found that the peak of the early, acute phase cytokine and chemokine levels was increased in injured p38α KO mice compared with injured WT mice. The increased cytokine levels in the p38α KO mice could not be accounted for by more infiltration of macrophages or neutrophils, or increased astrogliosis. By 7 d after injury, the cytokine and chemokine levels remained elevated in injured WT mice but not in p38α KO mice. Together, these data suggest that p38α balances the inflammatory response by acutely attenuating the early proinflammatory cytokine surge while perpetuating the chronic microglia activation after TBI.

Itraconazole and inhaled fluticasone causing hypothalamic-pituitary-adrenal axis suppression in adults with cystic fibrosis.

BACKGROUND: Although there have been case reports of hypothalamic-pituitary-adrenal (HPA) axis suppression in patients with cystic fibrosis (CF) caused by the combination of oral itraconazole and inhaled fluticasone, to date no study has assessed the incidence of this potentially serious side effect. METHODS: Synacthen tests were conducted on all patients with CF receiving itraconazole and inhaled fluticasone and an equal number of patients with CF receiving inhaled fluticasone but not itraconazole. Itraconazole levels were measured in patients receiving the therapy. RESULTS: Twelve patients receiving itraconazole and fluticasone underwent synacthen tests. All 12 had abnormal synacthen test results and 10/12 (83%) had HPA axis suppression. Two patients had severe HPA axis suppression with a peak cortisol <75 nmol/L and further 3 patients had moderately severe suppression with a peak cortisol <250 nmol/L. In contrast, only 2/12 on fluticasone alone had HPA axis suppression (both mild). The median (range) basal cortisol levels were significantly lower in those patients receiving itraconazole and inhaled fluticasone compared to those on fluticasone alone (219(22-508)nmol/L v 348(41-738)nnmol/L, p=0.02), similar results were seen for peak cortisol levels (404(59-706)nmol/L v 672(432-1178)nmol/L, p<0.001) and cortisol rise (179(37-240)nmol/L v 368(210-539)nmol/L, p<0.001). The median (range) itraconazole level was 5.5(1.7-14.7)mg/L. Neither itraconazole levels nor fluticasone dose correlated with the degree of adrenal suppression. CONCLUSIONS: In this study, all patients receiving itraconazole and inhaled fluticasone had abnormal synacthen test results. The incidence of HPA axis suppression with this treatment combination appears to be higher than that previously reported with itraconazole and inhaled budesonide.

Living with cystic fibrosis-related diabetes or type 1 diabetes mellitus: a comparative study exploring health-related quality of life and patients' reported experiences of hypoglycaemia.

OBJECTIVES: To compare patients with type 1 diabetes mellitus (T1DM) or cystic fibrosis-related diabetes (CFRD) on frequency and severity of symptoms suggestive of hypoglycaemia and diabetes-specific health-related quality of life (HRQoL). METHODS: This was a cross-sectional comparison study. Participants with T1DM or CFRD completed a questionnaire that assessed symptoms suggestive of hypoglycaemia and diabetes-specific HRQoL, and recorded episodes of low blood sugars in a prospective diary. Comparisons of responses were conducted, and Pearson product correlations were determined between HRQoL scores and other continuous variables. HRQoL scores were compared between the groups after adjusting for confounding factors. RESULTS: Diabetes in cystic fibrosis (CF) patients had a less negative impact on HRQoL than in T1DM patients. Both groups experienced hypoglycaemia, but loss of consciousness or needing help was more common in T1DM patients. Symptoms suggestive of hypoglycaemia were less of a problem for CFRD patients in terms of severity, with T1DM patients having more neuroglycopenic symptoms. DISCUSSION: Although the same percentage of patients in both groups reported experiencing hypoglycaemia, severity (e.g. symptoms and loss of consciousness) was higher for those with T1DM. Symptoms of hypoglycaemia appear to have a significant impact on HRQoL, and could account for the worse HRQoL in T1DM patients.

Isolation, motivation and balance: living with type 1 or cystic fibrosis-related diabetes.

AIMS AND OBJECTIVES: To explore patients' responses to developing and managing cystic fibrosis-related diabetes and to contrast their views with those of individuals with type 1 diabetes mellitus. BACKGROUND: The incidence of diabetes among people with cystic fibrosis has increased with improvement in life expectancy. However, little is known about how patients respond to and manage cystic fibrosis-related diabetes, and how this compares with people living with type 1 diabetes mellitus. DESIGN: Qualitative research was undertaken in order to fully explore meanings and views. METHODS: Semi-structured telephone or face-to-face interviews were conducted with patients who had cystic fibrosis-related diabetes or type 1 diabetes mellitus, during which, they discussed diagnosis and management of diabetes. Framework analysis was employed to identify themes and to consider similarities and differences between the two groups. RESULTS: Eleven cystic fibrosis-related diabetes and 12 type 1 diabetes mellitus patients were interviewed in 2006. Patients with cystic fibrosis-related diabetes described their diabetes diagnosis as a progression of their primary illness, management of which was important owing to the benefits it brought to their cystic fibrosis. Those with type 1 diabetes mellitus were more likely to report feeling psychologically low because of diabetes and to list long-term complications as a key factor motivating self-management. Both groups struggled to balance the demands of diabetes with other life and health obligations, and experienced isolation because of diabetes. Conclusions. Variation in perceptions recalled during interviews stemmed from diabetes being part of an existing life-threatening chronic illness in people with cystic fibrosis-related diabetes. Similarities and differences in attitudes and management practices were found, with less urgency regarding glucose monitoring and fewer information resources available for those with cystic fibrosis-related diabetes. RELEVANCE TO CLINICAL PRACTICE: Both groups need support for optimal diabetes management and access to appropriate resources outside specialist clinics. Web-based technologies could prove useful for those with cystic fibrosis-related diabetes as face-to-face interaction may be prevented owing to the risk of cross-infection.