Engineering subarachnoid trabeculae with electrospun poly(caprolactone) (PCL) scaffolds to study leptomeningeal metastasis in medulloblastoma.

Leptomeningeal metastasis (LM) occurs when cancer cells infiltrate the subarachnoid space (SAS) and metastasize to the fibrous structures that surround the brain and spinal cord. These structures include the leptomeninges (i.e., the pia mater and arachnoid mater), as well as subarachnoid trabeculae, which are collagen-rich fibers that provide mechanical structure for the SAS, support resident cells, and mediate flow of cerebrospinal fluid (CSF). Although there is a strong expectation that the presence of fibers within the SAS influences LM to be a major driver of tumor progression and lethality, exactly how trabecular architecture relates to the process of metastasis in cancer is poorly understood. This lack of understanding is likely due in part to the difficulty of accessing and manipulating this tissue compartment in vivo. Here, we utilized electrospun polycaprolactone (PCL) to produce structures bearing remarkable morphological similarity to native SAS fiber architecture. First, we profiled the native architecture of leptomeningeal and trabecular fibers collected from rhesus macaque monkeys, evaluating both qualitative and quantitative differences in fiber ultrastructure for various regions of the CNS. We then varied electrospinning parameters to produce a small library of PCL scaffolds possessing distinct architectures mimicking the range of fiber properties observed in vivo. For proof of concept, we studied the metastasis-related behaviors of human pediatric medulloblastoma cells cultured in different fiber microenvironments. These studies demonstrated that a more open, porous fiber structure facilitates DAOY cell spread across and infiltration into the meningeal mimic. Our results present a new tissue engineered model of the subarachnoid space and affirm the expectation that fiber architecture plays an important role in mediating metastasis-related behaviors in an in vitro model of pediatric medulloblastoma.

PCTR1 Enhances Repair and Bacterial Clearance in Skin Wounds.

Tissue injury elicits an inflammatory response that facilitates host defense. Resolution of inflammation promotes the transition to tissue repair and is governed, in part, by specialized pro-resolving mediators (SPM). The complete structures of a novel series of cysteinyl-SPM (cys-SPM) were recently elucidated, and proved to stimulate tissue regeneration in planaria and resolve acute inflammation in mice. Their functions in mammalian tissue repair are of interest. Here, nine structurally distinct cys-SPM were screened and PCTR1 uniquely enhanced human keratinocyte migration with efficacy similar to epidermal growth factor. In skin wounds of mice, PCTR1 accelerated closure. Wound infection increased PCTR1 that coincided with decreased bacterial burden. Addition of PCTR1 reduced wound bacteria levels and decreased inflammatory monocytes/macrophages, which was coupled with increased expression of genes involved in host defense and tissue repair. These results suggest that PCTR1 is a novel regulator of host defense and tissue repair, which could inform new approaches for therapeutic management of delayed tissue repair and infection.

Interventions for increasing colorectal cancer screening uptake among African-American men: A systematic review and meta-analysis.

BACKGROUND: African-American men have the lowest 5-year survival rate in the U.S. for colorectal cancer (CRC) of any racial group, which may partly stem from low screening adherence. It is imperative to synthesize the literature evaluating the effectiveness of interventions on CRC screening uptake in this population. MATERIALS AND METHODS: In this systematic review and meta-analysis, Medline, CINAHL, Embase, and Cochrane CENTRAL were searched for U.S.-based interventions that: were published after 1998-January 2020; included African-American men; and evaluated CRC screening uptake explicitly. Checklist by Cochrane Collaboration and Joanna Brigg were utilized to assess risk of bias, and meta-regression and sensitivity analyses were employed to identify the most effective interventions. RESULTS: Our final sample comprised 41 studies with 2 focused exclusively on African-American men. The most frequently adopted interventions were educational materials (39%), stool-based screening kits (14%), and patient navigation (11%). Most randomized controlled trials failed to provide details about the blinding of the participant recruitment method, allocation concealment method, and/or the outcome assessment. Due to high heterogeneity, meta-analysis was conducted among 17 eligible studies. Interventions utilizing stool-based kits or patient navigation were most effective at increasing CRC screening completion, with odds ratios of 9.60 (95% CI 2.89-31.82, p = 0.0002) and 2.84 (95% CI 1.23-6.49, p = 0.01). No evidence of publication bias was present for this study registered with the International Prospective Registry of Systematic Reviews (PROSPERO 2019 CRD42019119510). CONCLUSIONS: Additional research is warranted to uncover effective, affordable interventions focused on increasing CRC screening completion among African-American men. When designing and implementing future multicomponent interventions, employing 4 or fewer interventions types may reduce bias risk. Since only 5% of the interventions solely focused on African-American men, future theory-driven interventions should consider recruiting samples comprised solely of this population.

Resolvin D1 promotes efferocytosis in aging by limiting senescent cell-induced MerTK cleavage.

Inflammation-resolution is mediated by the balance between specialized pro-resolving mediators (SPMs) like resolvin D1 (RvD1) and pro-inflammatory factors, like leukotriene B4 (LTB4). A key cellular process of inflammation-resolution is efferocytosis. Aging is associated with defective inflammation-resolution and the accumulation of pro-inflammatory senescent cells (SCs). Therefore, understanding mechanism(s) that underpin this impairment is a critical gap. Here, using a model of hind limb ischemia-reperfusion (I/R) remote lung injury, we present evidence that aging is associated with heightened inflammation, impaired SPM:LT ratio, defective efferocytosis, and a decrease in MerTK levels in injured lungs. Treatment with RvD1 mitigated I/R lung injury in aging, promoted efferocytosis, and prevented the decrease of MerTK in injured lungs from old mice. Old MerTK cleavage-resistant mice (MerTKCR) exhibited less neutrophils or polymorpho nuclear cells infiltration and had improved efferocytosis compared with old WT controls. Mechanistically, macrophages that were treated with conditioned media (CM) from senescent cells had increased MerTK cleavage, impaired efferocytosis, and a defective RvD1:LTB4 ratio. Macrophages from MerTKCR mice were resistant to CM-induced efferocytosis defects and had an improved RvD1:LTB4 ratio. RvD1-stimulated macrophages prevented CM-induced MerTK cleavage and promoted efferocytosis. Together, these data suggest a new mechanism and a potential therapy to promote inflammation-resolution and efferocytosis in aging.

Resolvin D1 promotes the targeting and clearance of necroptotic cells.

Inflammation-resolution is a protective response that is mediated by specialized pro-resolving mediators (SPMs). The clearance of dead cells or efferocytosis is a critical cellular program of inflammation-resolution. Impaired efferocytosis can lead to tissue damage in prevalent human diseases, like atherosclerosis. Therefore understanding mechanisms associated with swift clearance of dead cells is of utmost clinical importance. Recently, the accumulation of necroptotic cells (NCs) was observed in human plaques and we postulated that this is due to defective clearance programs. Here we present evidence that NCs are inefficiently taken up by macrophages because they have increased surface expression of a well-known "don't eat me" signal called CD47. High levels of CD47 on NCs stimulated RhoA-pMLC signaling in macrophages that promoted "nibbling", rather than whole-cell engulfment of NCs. Anti-CD47 blocking antibodies limited RhoA-p-MLC signaling and promoted whole-cell NC engulfment. Treatment with anti-CD47 blocking antibodies to Ldlr-/- mice with established atherosclerosis decreased necrotic cores, limited the accumulation of plaque NCs and increased lesional SPMs, including Resolvin D1 (RvD1) compared with IgG controls. Mechanistically, RvD1 promoted whole-cell engulfment of NCs by decreasing RhoA signaling and activating CDC42. RvD1 specifically targeted NCs for engulfment by facilitating the release of the well-known "eat me signal" called calreticulin from macrophages in a CDC42 dependent manner. Lastly, RvD1 enhanced the clearance of NCs in advanced murine plaques. Together, these results suggest new molecules and signaling associated with the clearance of NCs, provide a new paradigm for the regulation of inflammation-resolution, and offer a potential treatment strategy for diseases where NCs underpin the pathology.

Study protocol for developing #CuttingCRC: a barbershop-based trial on masculinity barriers to care and colorectal cancer screening uptake among African-American men using an exploratory sequential mixed-methods design.

INTRODUCTION: Colorectal cancer (CRC) is preventable, as screening leads to the identification and removal of precancerous polyps. African-American men consistently have the highest CRC mortality rates, and their CRC-screening uptake remains low for complex reasons. Culture-specific masculinity barriers to care may contribute to the low uptake among African-American men. Examining these barriers to care is vital as CRC screening may challenge cultural role expectations of African-American men, whose tendency is to delay help-seeking medical care. Barbershops provide a pathway for reaching African-American men with masculinity barriers to care who are not regularly receiving healthcare services and CRC screening. This study aims to develop and pilot test a theory-driven, culture-specific, barbershop-based intervention targeting masculinity barriers to care and CRC-screening uptake among African-American men ages 45-75. METHODS AND ANALYSIS: Guided by the theory of planned behaviour and the behaviour change wheel, we will use a multistage mixed-methods study design, beginning with an exploratory sequential approach to validate items for subsequent use in a pilot mixed-methods intervention. First, we will collect and analyse qualitative data from focus groups, cognitive interviews and expert item review to validate and test a culture-specific Masculinity Barriers to Care Scale (MBCS) among African-American men. Next, we will administer the MBCS to our target population as an online quantitative survey and evaluate the association between scores and CRC-screening uptake. Then, we will consider existing evidence-based approaches, our integrated results (qualitative +quantitative), and community input to design a culture-specific, behavioural intervention aimed at increasing CRC-screening uptake among African-American men and feasible for barbershop delivery. We will test the peer intervention in a pilot study with a two-arm cluster randomised design (six barbershops, randomised by site) to reduce contamination and account for barbershop culture differences. Our primary outcomes for the pilot are recruitment, sample size estimation, preliminary efficacy and acceptability. ETHICS AND DISSEMINATION: Ethics approval was obtained from the University of Utah Institutional Review Board (00113679), who will also be responsible for receiving communication updates regarding important protocol modifications. To ensure confidentiality, data dispersed to project team members will be blinded of any identifying participant information. Study results will be disseminated through publications in peer-reviewed journals, community dialogue sessions, and presentations at conferences. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov identifier: NCT03733197 (Pre-results);https://clinicaltrials.gov/ct2/show/NCT03733197.

Publisher Correction: Dynamic changes to lipid mediators support transitions among macrophage subtypes during muscle regeneration.

In the version of this article initially published, two arrows in the far right plot of Fig. 3c were aimed incorrectly, and the error bars were missing in Fig. 6e,f. In Fig. 3c, the arrow labeled '5-LOX' should be aimed at the plot measuring LXB4, and the arrow labeled 'LTA4H' should be aimed at the plot measuring LTB4. The errors have been corrected in the HTML and PDF versions of the article.

Effect of Altitude on Veteran Suicide Rates.

Aims: Suicide rates in the general population in the United States are correlated with altitude. To explore factors contributing to suicide among military veterans, we examined the relationship between veteran state-level suicide rates and altitude for 2014, including firearm-related and nonfirearm-related rates. Methods: Pearson's coefficients were calculated for altitude and each outcome. Mixed linear models were used to determine the association between suicide and altitude while adjusting for demographic confounds. Results: State mean altitude was significantly correlated with total veteran suicide rate (r = 0.678, p < 0.0001), veteran firearm-related suicide rate (r = 0.578, p < 0.0001), and veteran nonfirearm suicide rate (r = 0.609, p < 0.0001). In mixed models, altitude was significantly correlated with total veteran suicide rate (ß = 0.331, p < 0.05), veteran firearm suicides (ß = 0.282, p < 0.05), and veteran nonfirearm suicides (ß = 0.393, p < 0.05). Conclusion: This study adds to evidence linking altitude and suicide rates, arguing for additional research into the relationship between altitude and suicide among veterans.

Cerebral bioenergetic differences measured by phosphorus-31 magnetic resonance spectroscopy between bipolar disorder and healthy subjects living in two different regions suggesting possible effects of altitude.

AIM: Increased oxidative stress in cerebral mitochondria may follow exposure to the systemic hypobaric hypoxia associated with residing at higher altitudes. Because mitochondrial dysfunction is implicated in bipolar disorder (BD) pathophysiology, this may impact the cerebral bioenergetics in BD. In this study, we evaluated the cerebral bioenergetics of BD and healthy control (HC) subjects at two sites, located at sea level and at moderate altitude. METHODS: Forty-three veterans with BD and 33 HC veterans were recruited in Boston (n = 22) and Salt Lake City (SLC; n = 54). Levels of phosphocreatine, ß nucleoside triphosphate (ßNTP), inorganic phosphate, and pH over total phosphate (TP) were measured using phosphorus-31 magnetic resonance spectroscopy in the following brain regions: anterior cingulate cortex and posterior occipital cortex, as well as bilateral prefrontal and occipitoparietal (OP) white matter (WM). RESULTS: A significant main effect of site was found in ßNTP/TP (Boston > SLC) and phosphocreatine/TP (Boston < SLC) in most cortical and WM regions, and inorganic phosphate/TP (Boston < SLC) in OP regions. A main effect analysis of BD diagnosis demonstrated a lower pH in posterior occipital cortex and right OP WM and a lower ßNTP/TP in right prefrontal WM in BD subjects, compared to HC subjects. CONCLUSION: The study showed that there were cerebral bioenergetic differences in both BD and HC veteran participants at two different sites, which may be partly explained by altitude difference. Future studies are needed to replicate these results in order to elucidate the dysfunctional mitochondrial changes that occur in response to hypobaric hypoxia.

Dynamic changes to lipid mediators support transitions among macrophage subtypes during muscle regeneration.

Muscle damage elicits a sterile immune response that facilitates complete regeneration. Here, we used mass spectrometry-based lipidomics to map the mediator lipidome during the transition from inflammation to resolution and regeneration in skeletal muscle injury. We observed temporal regulation of glycerophospholipids and production of pro-inflammatory lipid mediators (for example, leukotrienes and prostaglandins) and specialized pro-resolving lipid mediators (for example, resolvins and lipoxins) that were modulated by ibuprofen. These time-dependent profiles were recapitulated in sorted neutrophils and Ly6Chi and Ly6Clo muscle-infiltrating macrophages, with a distinct pro-resolving signature observed in Ly6Clo macrophages. RNA sequencing of macrophages stimulated with resolvin D2 showed similarities to transcriptional changes found during the temporal transition from Ly6Chi macrophage to Ly6Clo macrophage. In vivo, resolvin D2 increased Ly6Clo macrophages and functional improvement of the regenerating muscle. These results reveal dynamic lipid mediator signatures of innate immune cells and provide a proof of concept for their exploitable effector roles in muscle regeneration.

Brain choline in major depression: A review of the literature.

The focus of this review is to provide a synthesis of the current literature on the role of brain choline, as measured by proton magnetic resonance spectroscopy (1H-MRS), in major depressive disorder (MDD). The most recent 1H-MRS literature review took place over 10 years ago and, reflecting the high level of research on this topic, much has been learned since then. Higher brain choline levels have been linked to an increase in depression, and a cholinergic model for MDD development has been postulated. However, current 1H-MRS studies have been inconclusive regarding the role of choline in depression. Data from eighty-six peer-reviewed studies were analyzed for a random-effects model meta-analysis. Two significant findings are reported. Papers that did not report segmentation had a significant, moderate effect size. Higher choline concentrations in the frontal lobe were found in depressed patients, both in those who responded to treatment and those who did not, after treatment with psychiatric medication, repetitive transcranial magnetic stimulation, or electroconvulsive therapy. Findings from this review may add to existing information regarding the role of brain choline in MDD. This may provide a future target for treatment and drug development. It also may serve as a biomarker for treatment progress.