A year in review: brain barriers and brain fluids research in 2022.

This aim of this editorial is to highlight progress made in brain barrier and brain fluid research in 2022. It covers studies on the blood-brain, blood-retina and blood-CSF barriers (choroid plexus and meninges), signaling within the neurovascular unit and elements of the brain fluid systems. It further discusses how brain barriers and brain fluid systems are impacted in CNS diseases, their role in disease progression and progress being made in treating such diseases.

Historical loss: Implications for physical activity levels in American Indian adults.

PURPOSE: To investigate the relationship between daily thoughts about historical loss and daily levels of moderate to vigorous physical activity (MVPA) in American Indian (AI) adults residing on the Blackfeet reservation in Browning, Montana. METHODS: The study was designed and conducted using a community-based participatory research framework and ecological momentary assessment. Over a period of 1 week, 100 AI adults (mean age = 42.18, SD = 14.92) reported how often they thought about historical loss at the end of each day. During this week-long period, all participants wore a wrist-accelerometer to passively and objectively measure levels of physical activity. FINDINGS: We found that Blackfeet AI adults who reported thinking about historical loss more frequently over the course of the week had lower average levels of MVPA over the course of the week compared to Blackfeet AI adults who reported thinking about historical loss less frequently (B = -10.22, 95% CI = -13.83, -6.60). We also found that on days when Blackfeet AI adults thought more about historical loss compared to their weekly average, they had fewer minutes of MVPA compared to their weekly average of minutes of MVPA (B = -0.87, 95% CI = -1.48, -0.27). CONCLUSIONS: Our data indicate that thoughts about historical loss are linked to lower levels of MVPA. Given high incidence of chronic health conditions linked to physical inactivity in AIs, more work is needed to identify the mechanisms through which thoughts about historical loss may inhibit physical activity in this population.

Emotion Regulation Strategies Relate to Ambulatory Cardiovascular Activity in an American Indian Community.

OBJECTIVE: Poor emotion regulation is associated with risk for cardiovascular disease. However, much of this research is conducted in primarily White samples, thus limiting our understanding of this relationship in other racial/ethnic groups. American Indians (AIs) are uniquely and disproportionately at risk for cardiovascular disease. As such, the present study aimed to examine the relationships between emotion regulation strategies and ambulatory cardiovascular activity in an entirely AI sample. METHODS: The sample consisted of 100 AI adults living on a tribal reservation. Emotion regulation strategies (expressive suppression, cognitive reappraisal) were assessed via the Emotion Regulation Questionnaire. Using ecological momentary assessment, daily measurements of psychological stress and ambulatory cardiovascular activity were taken during a 7-day monitoring period. Statistical analyses included bivariate correlations, hierarchical linear regression models, and mediation models. RESULTS: Expressive suppression was associated with higher systolic and diastolic blood pressure, as well as higher pulse rate. In contrast, cognitive reappraisal was associated with lower systolic and diastolic blood pressure, lower pulse rate, and lower average daily psychological stress. These results remained statistically significant after adjusting for age, sex, body mass index, anxiety, depression, and early life trauma. In addition, psychological stress mediated the associations between blood pressure and cognitive reappraisal, but not expressive suppression. CONCLUSIONS: These results provide preliminary evidence for divergent associations of two emotion regulation strategies with cardiovascular activity and psychological stress in an AI community. Modifying health interventions to include training in effective emotion regulation may be beneficial.

Advances in brain barriers and brain fluids research in 2021: great progress in a time of adversity.

This editorial highlights advances in brain barrier and brain fluid research in 2021. It covers research on components of the blood-brain barrier, neurovascular unit and brain fluid systems; how brain barriers and brain fluid systems are impacted by neurological disorders and their role in disease progression; and advances in strategies for treating such disorders.

COVID-19 and food insecurity in the Blackfeet Tribal Community.

To examine the impact of the COVID-19 pandemic on food insecurity in the Blackfeet American Indian Tribal Community. American Indian adults residing on the Blackfeet reservation in Northwest Montana (n = 167) participated in a longitudinal survey across 4 months during the COVID-19 pandemic (August 24, 2020- November 30, 2020). Participants reported on demographics and food insecurity. We examined trajectories of food insecurity alongside COVID-19 incidence. While food insecurity was high in the Blackfeet community preceding the pandemic, 79% of our sample reported significantly greater food insecurity at the end of the study. Blackfeet women were more likely to report higher levels of food insecurity and having more people in the household predicted higher food insecurity. Longitudinal data indicate that the COVID-19 pandemic exacerbated already high levels of food insecurity in the Blackfeet community. Existing programs and policies are inadequate to address this public health concern in AI tribal communities.

Historical Loss: Implications for Health of American Indians in the Blackfeet Community.

BACKGROUND: Historical loss in American Indians (AIs) is believed to contribute to high incidence of mental health disorders, yet less is known about the associations between historical loss and physical health. PURPOSE: To investigate whether frequency of thought about historical loss predicts risk factors for chronic physical health conditions in an AI community. METHODS: Using Community Based Participatory research (CBPR) and Ecological Momentary Assessment (EMA), we measured frequency of thoughts about historical loss in 100 AI adults residing on the Blackfeet reservation. Participants completed a 1-week monitoring period, during which ambulatory blood pressure and daily levels of psychological stress were measured. At the end of the week, we collected a dried blood spot sample for measurement of C-reactive protein (CRP). RESULTS: In hierarchical linear regression models controlling for demographics and relevant covariates, greater frequency of thoughts about historical loss predicted higher average daily psychological stress (B = .55, t = 6.47, p < .001, ΔR2 = .30) and higher levels of CRP (B = .33, t = 3.93, p < .001, ΔR2 = .10). Using linear mixed modeling with relevant covariates, we found that greater thoughts about historical loss were associated with higher systolic ambulatory blood pressure (B = .32, 95% CI = .22-.42, t = 6.48, p < .001, ΔR2 = .25; Fig. 1c) and greater diastolic ambulatory blood pressure (B = .19, 95% CI = .11-.27, t = 4.73, p < .001, ΔR2 = .19). CONCLUSIONS: The data suggest that frequency of thought about historical loss may contribute to increased subclinical risk for cardiovascular disease in the Blackfeet community.

Brain Endothelial Cells: Metabolic Flux and Energy Metabolism.

The neurovascular unit (NVU) consists of multiple cell types including brain endothelial cells, pericytes, astrocytes, and neurons that function collectively to maintain homeostasis within the CNS microenvironment. As the principal barrier-forming component of the NVU, the endothelial cells perform an array of complex functions that require substantial energy resources. The principal metabolic pathways for producing ATP are glycolysis and mitochondrial oxidative phosphorylation. While previous studies have demonstrated that glycolysis is a primary pathway for most endothelial cells, details about the energy producing pathways of brain endothelial cells are not fully characterized. The contributions of glycolysis and mitochondrial respiration to energy metabolism are quantifiable using metabolic flux analysis that measures cellular oxygen consumption and acidification (proton production) in a closed microtiter plate format. ATP production rates are then calculated. The bioenergetics of the human brain microvascular endothelial cell line, hCMEC/D3, indicate that these cells exhibit relatively elevated rates of glycolytic flux and glycolytic ATP production, thus confirming their glycolytic nature even in the presence of abundant oxygen. Furthermore, energy producing pathways involving mitochondrial respiration are relatively low, although contributing significantly to total ATP production. Interestingly, the bioenergetics of the hCMEC/D3 cells are relatively similar to those of human primary brain microvascular endothelial cells (hBVECs). These findings allow a quantitative understanding of the bioenergetics of brain endothelial cells in a cultured and proliferative state and also provide a platform for comparative studies of disease states and conditions involving exposures to drugs or metabolic disruptors.

Loneliness and sleep in the American Indian Blackfeet community.

BACKGROUND: Sleep is largely understudied in American Indians (AIs), even though sleep is implicated in the chronic diseases which disproportionately affect AI communities. OBJECTIVE: To investigate relationships between daily self-reported loneliness and sleep as measured with actigraphy. METHODS: In a sample of 98 Blackfeet adults living on the Blackfeet reservation in Montana, we used Ecological Momentary Assessment and actigraphy over a week-long period to investigate relationships between loneliness and sleep. Loneliness was measured daily using the Short Loneliness Scale and actigraphy was used to measure total sleep time, sleep onset latency (SOL), wake after sleep onset (WASO), and sleep efficiency (SE). RESULTS: Using a series of generalized linear mixed-effects models controlling for demographic characteristics, anxiety and depressive symptoms, and adverse childhood experiences, we found that those who were lonelier had higher WASO and SOL, and lower SE relative to those who were less lonely. Within-subject effects indicate that participants who were lonelier for a given day relative to their own weekly average had higher WASO that night relative to their own weekly average. CONCLUSIONS: Our findings provide initial preliminary evidence suggesting that loneliness may be a psychosocial factor which contributes to poor sleep in AI communities.

Brain Barriers and brain fluids research in 2020 and the fluids and barriers of the CNS thematic series on advances in in vitro modeling of the blood-brain barrier and neurovascular unit.

This editorial discusses advances in brain barrier and brain fluid research in 2020. Topics include: the cerebral endothelium and the neurovascular unit; the choroid plexus; the meninges; cerebrospinal fluid and the glymphatic system; disease states impacting the brain barriers and brain fluids; drug delivery to the brain. This editorial also highlights the recently completed Fluids Barriers CNS thematic series entitled, 'Advances in in vitro modeling of the blood-brain barrier and neurovascular unit'. Such in vitro modeling is progressing rapidly.

Addressing BBB Heterogeneity: A New Paradigm for Drug Delivery to Brain Tumors.

Effective treatments for brain tumors remain one of the most urgent and unmet needs in modern oncology. This is due not only to the presence of the neurovascular unit/blood-brain barrier (NVU/BBB) but also to the heterogeneity of barrier alteration in the case of brain tumors, which results in what is referred to as the blood-tumor barrier (BTB). Herein, we discuss this heterogeneity, how it contributes to the failure of novel pharmaceutical treatment strategies, and why a "whole brain" approach to the treatment of brain tumors might be beneficial. We discuss various methods by which these obstacles might be overcome and assess how these strategies are progressing in the clinic. We believe that by approaching brain tumor treatment from this perspective, a new paradigm for drug delivery to brain tumors might be established.

Development of Novel Analogs of the Monocarboxylate Transporter Ligand FACH and Biological Validation of One Potential Radiotracer for Positron Emission Tomography (PET) Imaging.

Monocarboxylate transporters 1-4 (MCT1-4) are involved in several metabolism-related diseases, especially cancer, providing the chance to be considered as relevant targets for diagnosis and therapy. [18F]FACH was recently developed and showed very promising preclinical results as a potential positron emission tomography (PET) radiotracer for imaging of MCTs. Given that [18F]FACH did not show high blood-brain barrier permeability, the current work is aimed to investigate whether more lipophilic analogs of FACH could improve brain uptake for imaging of gliomas, while retaining binding to MCTs. The 2-fluoropyridinyl-substituted analogs 1 and 2 were synthesized and their MCT1 inhibition was estimated by [14C]lactate uptake assay on rat brain endothelial-4 (RBE4) cells. While compounds 1 and 2 showed lower MCT1 inhibitory potencies than FACH (IC50 = 11 nM) by factors of 11 and 25, respectively, 1 (IC50 = 118 nM) could still be a suitable PET candidate. Therefore, 1 was selected for radiosynthesis of [18F]1 and subsequent biological evaluation for imaging of the MCT expression in mouse brain. Regarding lipophilicity, the experimental log D7.4 result for [18F]1 agrees pretty well with its predicted value. In vivo and in vitro studies revealed high uptake of the new radiotracer in kidney and other peripheral MCT-expressing organs together with significant reduction by using specific MCT1 inhibitor α-cyano-4-hydroxycinnamic acid. Despite a higher lipophilicity of [18F]1 compared to [18F]FACH, the in vivo brain uptake of [18F]1 was in a similar range, which is reflected by calculated BBB permeabilities as well through similar transport rates by MCTs on RBE4 cells. Further investigation is needed to clarify the MCT-mediated transport mechanism of these radiotracers in brain.

Measuring aggregation in parasite populations.

Aggregation, a fundamental feature of parasite distributions, has been measured using a variety of indices. We use the definition that parasite-host system A is more aggregated than parasite-host system B if any given proportion of the parasite population is concentrated in a smaller proportion of the host population A than of host population B. This leads to indices based on the Lorenz curve such as the Gini index (Poulin's D), coefficient of variation and the Hoover index, all of which measure departure from a uniform distribution. The Hoover index is particularly useful because it can be interpreted directly in terms of parasites and hosts. An alternative view of aggregation is degree of departure from a Poisson (or random) distribution, as used in the index of dispersion and the negative binomial k. These and Lloyd's mean crowding index are reinterpreted and connected back to Lorenz curves. Aggregation has occasionally been defined as the slope from Taylor's law, although the slope appears unrelated to other indices. The Hoover index may be the method of choice when data points are available, and the coefficient of variation when only variance and mean are given.

This was the year that was: brain barriers and brain fluid research in 2019.

This editorial highlights advances in brain barrier and brain fluid research published in 2019, as well as addressing current controversies and pressing needs. Topics include recent advances related to: the cerebral endothelium and the neurovascular unit; the choroid plexus, arachnoid membrane; cerebrospinal fluid and the glymphatic hypothesis; the impact of disease states on brain barriers and brain fluids; drug delivery to the brain; and translation of preclinical data to the clinic. This editorial also mourns the loss of two important figures in the field, Malcolm B. Segal and Edward G. Stopa.

Service users' experiences of receiving a diagnosis of borderline personality disorder: A systematic review.

There is ongoing controversy regarding the borderline personality disorder (BPD) diagnosis. Whilst the experiences of people living with BPD have been widely acknowledged, the process of receiving the diagnosis is poorly described. This systematic review aimed to synthesize the existing research exploring people's experiences of receiving a diagnosis of BPD, as well as examining what is considered best practice in the diagnostic delivery process. The findings from 12 qualitative studies were synthesized using thematic analysis, generating two overarching themes: negative and positive experiences of receiving a diagnosis of BPD. These themes were described using the following sub-themes: the communication of diagnosis and meaning made of it, validity around diagnosis and attitudes of others. Results indicate that there is a substantial difference between a well-delivered and poorly delivered diagnosis. The diagnostic delivery process is fundamental to how people understand and interpret the BPD diagnosis. The way in which the BPD diagnosis is shared with people can ultimately shape their views about hope for recovery and their subsequent engagement with services. © 2020 John Wiley & Sons, Ltd.

A novel MCT1 and MCT4 dual inhibitor reduces mitochondrial metabolism and inhibits tumour growth of feline oral squamous cell carcinoma.

Monocarboxylate transporters (MCTs) support tumour growth by regulating the transport of metabolites in the tumour microenvironment. High MCT1 or MCT4 expression is correlated with poor outcomes in human patients with head and neck squamous cell carcinoma (HNSCC). Recently, drugs targeting these transporters have been developed and may prove to be an effective treatment strategy for HNSCC. Feline oral squamous cell carcinoma (OSCC) is an aggressive and treatment-resistant malignancy resembling advanced or recurrent HNSCC. The goals of this study were to investigate the effects of a previously characterized dual MCT1 and MCT4 inhibitor, MD-1, in OSCC as a novel treatment approach for feline oral cancer. We also sought to determine the potential of feline OSCC as a large animal model for the further development of MCT inhibitors to treat human HNSCC. In vitro, MD-1 reduced the viability of feline OSCC and human HNSCC cell lines, altered glycolytic and mitochondrial metabolism and synergized with platinum-based chemotherapies. While MD-1 treatment increased lactate concentrations in an HNSCC cell line, the inhibitor failed to alter lactate levels in feline OSCC cells, suggesting an MCT-independent activity. In vivo, MD-1 significantly inhibited tumour growth in a subcutaneous xenograft model and prolonged overall survival in an orthotopic model of feline OSCC. Our results show that MD-1 may be an effective therapy for the treatment of feline oral cancer. Our findings also support the further investigation of feline OSCC as a large animal model to inform the development of MCT inhibitors and future clinical studies in human HNSCC.

Development of Novel Silyl Cyanocinnamic Acid Derivatives as Metabolic Plasticity Inhibitors for Cancer Treatment.

Novel silyl cyanocinnamic acid derivatives have been synthesized and evaluated as potential anticancer agents. In vitro studies reveal that lead derivatives 2a and 2b have enhanced cancer cell proliferation inhibition properties when compared to the parent monocarboxylate transporter (MCT) inhibitor cyano-hydroxycinnamic acid (CHC). Further, candidate compounds exhibit several-fold more potent MCT1 inhibition properties as determined by lactate-uptake studies, and these studies are supported by MCT homology modeling and computational inhibitor-docking studies. In vitro effects on glycolysis and mitochondrial metabolism also illustrate that the lead derivatives 2a and 2b lead to significant effects on both metabolic pathways. In vivo systemic toxicity and efficacy studies in colorectal cancer cell WiDr tumor xenograft demonstrate that candidate compounds are well tolerated and exhibit good single agent anticancer efficacy properties.

Novel N,N-dialkyl cyanocinnamic acids as monocarboxylate transporter 1 and 4 inhibitors.

Potent and dual monocarboxylate transporter (MCT) 1 and 4 inhibitors have been developed for the first time as potential anticancer agents based on α-cyanocinnamic acid structural template. Candidate inhibitors 1-9 have been evaluated for in vitro cell proliferation against MCT1 and MCT4 expressing cancer cell lines. Potential MCT1 and MCT4 binding interactions of the lead compound 9 have been studied through homology modeling and molecular docking prediction. In vitro effects on extracellular flux via glycolysis and mitochondrial stress tests suggest that candidate compounds 3 and 9 disrupt glycolysis and OxPhos efficiently in MCT1 expressing colorectal adenocarcinoma WiDr and MCT4 expressing triple negative breast cancer MDA-MB-231 cells. Fluorescence microscopy analyses in these cells also indicate that compound 9 is internalized and concentrated near mitochondria. In vivo tumor growth inhibition studies in WiDr and MDA-MB-231 xenograft tumor models in mice indicate that the candidate compound 9 exhibits a significant single agent activity.

Development and radiosynthesis of the first 18 F-labeled inhibitor of monocarboxylate transporters (MCTs).

Monocarboxylate transporters 1 and 4 (MCT1 and MCT4) are involved in tumor development and progression. Their expression levels are related to clinical disease prognosis. Accordingly, both MCTs are promising drug targets for treatment of a variety of human cancers. The noninvasive imaging of these MCTs in cancers is regarded to be advantageous for assessing MCT-mediated effects on chemotherapy and radiosensitization using specific MCT inhibitors. Herein, we describe a method for the radiosynthesis of [18 F]FACH ((E)-2-cyano-3-{4-[(3-[18 F]fluoropropyl)(propyl)amino]-2-methoxyphenyl}acrylic acid), as a novel radiolabeled MCT1/4 inhibitor for imaging with PET. A fluorinated analog of α-cyano-4-hydroxycinnamic acid (FACH) was synthesized, and the inhibition of MCT1 and MCT4 was measured via an L-[14 C]lactate uptake assay. Radiolabeling was performed by a two-step protocol comprising the radiosynthesis of the intermediate (E)/(Z)-[18 F]tert-Bu-FACH (tert-butyl (E)/(Z)-2-cyano-3-{4-[(3-[18 F]fluoropropyl)(propyl)amino]-2-methoxyphenyl}acrylate) followed by deprotection of the tert-butyl group. The radiofluorination was successfully implemented using either K[18 F]F-K2.2.2 -carbonate or [18 F]TBAF. The final deprotected product [18 F]FACH was only obtained when [18 F]tert-Bu-FACH was formed by the latter procedure. After optimization of the deprotection reaction, [18 F]FACH was obtained in high radiochemical yields (39.6 ± 8.3%, end of bombardment (EOB) and radiochemical purity (greater than 98%).