Youth Preseason Performance on the Sport Concussion Assessment Tool 5 Across Multiple Sports.

OBJECTIVE: To examine preseason Sport Concussion Assessment Tool 5 (SCAT5) performance of adolescent sport participants by environment (in-person/virtual), sex, age, concussion history, collision/noncollision sport participation, and self-reported medical diagnoses. DESIGN: Cross-sectional. SETTING: Canadian community and high-school sport settings. PARTICIPANTS: Three thousand eight hundred five adolescent (2493 male, 1275 female, and 37 did not disclose; 11- to 19-year-old) sport participants. ASSESSMENT OF RISK FACTORS: Sport Concussion Assessment Tool 5 administration method (in-person/virtual), sex (male/female/unreported), age (years), concussion history (0/1/2/3+), collision/noncollision sport participant, and self-reported medical diagnoses [attention deficit disorder or attention-deficit/hyperactivity disorder, headache/migraine, learning disability, and psychiatric disorder (ie, anxiety/depression/other)]. OUTCOME MEASURES: Preseason SCAT5 outcomes including total number of symptoms (TNS; /22), symptom severity score (SSS; /132), Standardized Assessment of Concussion (SAC; /50), and modified Balance Error Scoring System (mBESS; /30). RESULTS: Multiple multilevel linear or Poisson regression complete case analyses adjusting for clustering and robust standard errors, with ß-coefficients (95% CI) back-transformed to indicate an increase/decrease in SCAT5 subdomains when relevant for clinical interpretation. Virtual (V) performance was associated with fewer symptoms reported [TNS Difference V-IP = -1.53 (95% CI, -2.22 to -0.85)], lower SSS [-2.49 (95% CI, -4.41 to -0.58)], and fewer mBESS errors (IP) [-0.52 (95% CI, -0.77 to -0.27)] compared with in-person. For every one-year increase in age, more symptoms [TNS = 0.22 (95% CI, 0.01-0.44)], higher SSS [0.52 (95% CI, 0.01-1.06)], higher SAC [0.27 (95% CI, 0.15-0.38), and poorer balance [mBESS = -0.19 (-0.28 to -0.09)] were observed. Differences between males and females were also seen across all SCAT5 outcomes. Individuals reporting any medical diagnosis or 3+ concussion history also reported more symptoms (TNS) and higher SSS than those who did not. CONCLUSIONS: Administration environment, sex, age, concussion history, and medical diagnoses were associated with SCAT5 subdomains and are important considerations when interpreting the SCAT5 results.

Cellular traits regulate fluorescence-based light-response phenotypes of coral photosymbionts living in-hospite.

Diversity across algal family Symbiodiniaceae contributes to the environmental resilience of certain coral species. Chlorophyll-a fluorescence measurements are frequently used to determine symbiont health and resilience, but more work is needed to refine these tools and establish how they relate to underlying cellular traits. We examined trait diversity in symbionts from the generas Cladocopium and Durusdinium, collected from 12 aquacultured coral species. Photophysiological metrics (ΦPSII, σPSII, ρ, τ1, τ2, antenna bed quenching, non-photochemical quenching, and qP) were assessed using a prototype multi-spectral fluorometer over a variable light protocol which yielded a total of 1,360 individual metrics. Photophysiological metrics were then used to establish four unique light-response phenotypic variants. Corals harboring C15 were predominantly found within a single light-response phenotype which clustered separately from all other coral fragments. The majority of Durusdinium dominated colonies also formed a separate light-response phenotype which it shared with a few C1 dominated corals. C15 and D1 symbionts appear to differ in which mechanisms they use to dissipate excess light energy. Spectrally dependent variability is also observed across light-response phenotypes that may relate to differences in photopigment utilization. Symbiont cell biochemical and structural traits (atomic C:N:P, cell size, chlorophyll-a, neutral lipid content) was also assessed within each sample and differ across light-response phenotypes, linking photophysiological metrics with underlying primary cellular traits. Strong correlations between first- and second-order traits, such as Quantum Yield and cellular N:P content, or light dissipation pathways (qP and NPQ) and C:P underline differences across symbiont types and may also provide a means for using fluorescence-based metrics as biomarkers for certain primary-cellular traits.

Serum soluble epoxide hydrolase related oxylipins and major depression in patients with type 2 diabetes.

BACKGROUND: People with type 2 diabetes mellitus (T2DM) are at increased risk for depression. Both conditions are associated with disturbances in polyunsaturated fatty acids. Omega-3 and omega-6 fatty acids can be converted into bioactive epoxides by cytochrome P450s (CYP450), which play pro-resolving roles in the inflammatory response; however, soluble epoxide hydrolase (sEH) metabolizes epoxides into diols, which lack pro-resolving functions and can be cytotoxic. Here, we survey serum CYP450- and sEH-derived metabolite concentrations in people with T2DM with and without a major depressive episode. METHODS: Sunnybrook Type 2 Diabetes Study (NCT04455867) participants experiencing a major depressive episode (research version of the Structured Clinical Interview for DSM-5 criteria) were matched 1:1 for gender, glycosylated hemoglobin A1c and body mass index to participants without a current depressive episode. Depression severity was assessed using the Beck Depression Inventory 2nd Edition (BDI-II). From fasting morning blood, unesterified serum oxylipins were quantified by ultra-high-performance liquid chromatography tandem mass spectrometry following solid phase extraction, and interleukin-6 (IL-6) by enzyme-linked immunosorbent assay. RESULTS: Between 20 depressed and 20 non-depressed participants (mean age 58.9 ± 8.5 years, 65% women) with T2DM, several sEH-derived fatty acid diols, but not IL-6, were higher among those with a depressive episode (effect sizes up to d = 0.796 for 17,18-DiHETE, a metabolite of eicosapentaenoic acid [EPA]; t = 2.516, p = 0.016). Among people with a depressive episode, two epoxides were correlated with lower BDI-II scores: 12(13)-EpOME (ρ = -0.541, p = 0.014) and 10(11)-EpDPE (ρ = -0.444, p = 0.049), metabolites of linoleic acid and docosahexaenoic acid (DHA), respectively, while the ratio of 12,13-DiHOME/12(13)-EpOME was correlated with higher BDI-II scores (ρ = 0.513, p = 0.021). CONCLUSIONS: In people with T2DM, major depressive episodes and depressive symptom severity were associated with an oxylipin profile consistent with elimination of pro-resolving lipid mediators by sEH.

Serum osteocalcin is associated with subjective stress in people with depression and type 2 diabetes.

BACKGROUND: Low serum osteocalcin is a risk factor for type 2 diabetes mellitus (T2DM), and osteocalcin release from bone is associated with an acute stress response in mice. Both diabetes and stress are associated with depression. Here, we assess relationships between serum osteocalcin, depression and subjective stress in people with T2DM. METHODS: Participants with T2DM (HbA1c above 6.4 %, impaired fasting glucose or impaired glucose tolerance) were assessed for a major depressive episode using the research version of the Structured Clinical Interview for DSM-5 depression criteria (SCID-5RV). Subjective stress over the past month was assessed using the Perceived Stress Scale (PSS). Serum carboxylated (cOCN) and fully decarboxylated (dcOCN) osteocalcin were assayed from fasting morning blood by commercial enzyme-linked immunosorbent assay. RESULTS: Among 95 participants (mean age 62.4 ± 9.9, 51 % women), 22 % were experiencing a depressive episode (9 men, 12 women). The presence of a depressive episode was not associated with dcOCN or cOCN concentrations; however, higher concentrations of cOCN were associated with higher PSS scores in participants with depression (r = 0.585, p = 0.005). In an analysis of covariance model controlling for age, sex, body mass index, glycemic control (glycosylated hemoglobin), insulin resistance (homeostatic model), depression, and antidepressant use, cOCN was associated with PSS scores (F=10.302, p = 0.002), and this relationship was stronger in those with depression (depression × cOCN interaction F=4.978, p = 0.028). Although associations between dcOCN concentrations and PSS scores did not reach significance, the same trend seen with cOCN concentrations was observed in participants with depression for dcOCN (r=0.365, p=0.10), and for a depression × dcOCN interaction associated with PSS scores in the whole group (F=2.165, p = 0.15). CONCLUSIONS: Osteocalcin is a neuroendocrine marker associated with perceived chronic stress among people with T2DM experiencing a depressive episode.

Transcriptomic analysis reveals that BMP4 sensitizes glioblastoma tumor-initiating cells to mechanical cues.

The poor prognosis of glioblastoma (GBM) is associated with a highly invasive stem-like subpopulation of tumor-initiating cells (TICs), which drive recurrence and contribute to intra-tumoral heterogeneity through differentiation. These TICs are better able to escape extracellular matrix-imposed mechanical restrictions on invasion than their more differentiated progeny, and sensitization of TICs to extracellular matrix mechanics extends survival in preclinical models of GBM. However, little is known about the molecular basis of the relationship between TIC differentiation and mechanotransduction. Here we explore this relationship through a combination of transcriptomic analysis and studies with defined-stiffness matrices. We show that TIC differentiation induced by bone morphogenetic protein 4 (BMP4) suppresses expression of proteins relevant to extracellular matrix signaling and sensitizes TIC spreading to matrix stiffness. Moreover, our findings point towards a previously unappreciated connection between BMP4-induced differentiation, mechanotransduction, and metabolism. Notably, stiffness and differentiation modulate oxygen consumption, and inhibition of oxidative phosphorylation influences cell spreading in a stiffness- and differentiation-dependent manner. Our work integrates bioinformatic analysis with targeted molecular measurements and perturbations to yield new insight into how morphogen-induced differentiation influences how GBM TICs process mechanical inputs.

Respiratory syncytial virus prophylaxis in infants with congenital airway anomalies compared to standard indications and complex medical disorders.

An observational study was conducted of children < 2 years who received ≥ 1 dose of palivizumab in 32 Canadian institutions from 2005 to 2017. We compared respiratory illness (RIH) and respiratory syncytial virus-related hospitalization (RSVH) hazards in children with a congenital airway anomaly (CAA) versus those prophylaxed for standard indications (SI) and serious medical disorders (SMD). Data were assembled on neonatal course, demographics, palivizumab utilization and adherence, and respiratory illness events, and analyzed using ANOVA, chi-square tests and Cox proportional hazards. Twenty-five thousand three children (1219 CAA, 3538 SMD, and 20,246 SI) were enrolled. Palivizumab adherence was 74.8% overall and similar across groups. For 2054 respiratory-related events, 1724 children were hospitalized. RIH rates were 13.6% (CAA), 9.6% (SMD), and 6.0% (SI). RSVH rates were 2.4% (CAA), 1.6% (SMD), and 1.5% (SI). After adjustment for demographic and neonatal differences, children with a CAA had a significantly increased RIH and RSVH hazard relative to SI (RIH, HR = 1.6, 95% CI 1.2-2.2, p = 0.002; RSVH, HR = 2.1, 95% CI 1.0-4.4, p = 0.037) but similar to SMD (RIH, HR = 1.3, 95% CI 0.9-1.9, p = 0.190; RSVH, HR = 1.7, 95% CI 0.7-4.1, p = 0.277).Conclusion: Children with a CAA experience higher RIH risk. RSVH hazard was similar between CAA and SMD but higher for CAA compared to SI, implying that this population requires surveillance for RSV prophylaxis. What is Known: • Children with congenital airway anomalies (CAA) are at risk for respiratory tract illness and respiratory syncytial virus-related hospitalization (RSVH) with accompanying morbidity and mortality • RSV prophylaxis may be useful in children with a CAA, but is not routinely recommended What is New: • Children with a CAA had a 1.6-2.3 fold greater risk of respiratory-related hospitalization and RSVH compared to those prophylaxed for standard, approved indications and serious medical disorders. • RSVH risk in children aged < 2 years with either upper or lower airway anomalies is similar. Children with a CAA require careful surveillance during the RSV season and prophylaxis may be appropriate.

Adherence and outcomes: a systematic review of palivizumab utilization.

INTRODUCTION: Palivizumab is a humanized monoclonal antibody used for respiratory syncytial virus (RSV) prophylaxis. RSV is the primary cause of lower respiratory tract infection in children aged <2 years, and can give rise to high-burden hospitalization and respiratory complications in later life. Adherence to a monthly dosing regimen, both in timing and injection number, is essential to sustain therapeutic levels of palivizumab and maintain protective status. Deviation from the approved dosing schedule may reduce the efficacy of palivizumab and increase the risk of breakthrough RSV infection and hospitalization. Areas covered: There is no standardized definition of adherence to palivizumab treatment. This review addresses the wide variability in defining and reporting adherence to palivizumab prophylaxis across different studies. The review assesses whether a relationship exists in the outcomes reported in studies relative to the monthly adherence protocol as defined in published randomized controlled trials of the efficacy and safety of palivizumab. Expert commentary: Standardized detailed reporting of adherence to palivizumab prophylaxis using consistent definitions will help provide a more robust level of evidence. This information may be important when considering variations in effectiveness, alterations to recommendations and guidelines, and cost-effectiveness of treatment.

Constitutive activation of myosin-dependent contractility sensitizes glioma tumor-initiating cells to mechanical inputs and reduces tissue invasion.

Tumor-initiating cells (TIC) perpetuate tumor growth, enable therapeutic resistance, and drive initiation of successive tumors. Virtually nothing is known about the role of mechanotransductive signaling in controlling TIC tumorigenesis, despite the recognized importance of altered mechanics in tissue dysplasia and the common observation that extracellular matrix (ECM) stiffness strongly regulates cell behavior. To address this open question, we cultured primary human glioblastoma (GBM) TICs on laminin-functionalized ECMs spanning a range of stiffnesses. Surprisingly, we found that these cells were largely insensitive to ECM stiffness cues, evading the inhibition of spreading, migration, and proliferation typically imposed by compliant ECMs. We hypothesized that this insensitivity may result from insufficient generation of myosin-dependent contractile force. Indeed, we found that both pharmacologic and genetic activation of cell contractility through RhoA GTPase, Rho-associated kinase, or myosin light chain kinase restored stiffness-dependent spreading and motility, with TICs adopting the expected rounded and nonmotile phenotype on soft ECMs. Moreover, constitutive activation of RhoA restricted three-dimensional invasion in both spheroid implantation and Transwell paradigms. Orthotopic xenotransplantation studies revealed that control TICs formed tumors with classical GBM histopathology including diffuse infiltration and secondary foci, whereas TICs expressing a constitutively active mutant of RhoA produced circumscribed masses and yielded a 30% enhancement in mean survival time. This is the first direct evidence that manipulation of mechanotransductive signaling can alter the tumor-initiating capacity of GBM TICs, supporting further exploration of these signals as potential therapeutic targets and predictors of tumor-initiating capacity within heterogeneous tumor cell populations.

Matrix regulation of tumor-initiating cells.

The recognition that the progression of many tumors may be driven by specific subpopulations of cells with stem/progenitor-like properties (tumor-initiating cells or TICs, a.k.a. cancer stem cells) represents an important recent paradigm shift in cancer biology and therapeutics. TICs in solid tissues are expected to interface with the extracellular matrix (ECM), which can strongly influence cell behavior through a variety of biochemical and biophysical mechanisms. Understanding ECM regulation of TIC behavior is important for developing strategies to isolate, expand, and characterize TICs in a laboratory setting and for understanding the roles ECM-based inputs may play in disease progression and therapy. In this chapter, we discuss how the ECM regulates TICs, starting with a brief overview of TIC biology, isolation, and characterization, molecular mechanisms through which TICs may be regulated by ECM-based signals, and the potential importance of these signals to TIC-driven tumor progression and metastasis.

Combined simulation and experimental study of large deformation of red blood cells in microfluidic systems.

We investigate the biophysical characteristics of healthy human red blood cells (RBCs) traversing microfluidic channels with cross-sectional areas as small as 2.7 × 3 µm. We combine single RBC optical tweezers and flow experiments with corresponding simulations based on dissipative particle dynamics (DPD), and upon validation of the DPD model, predictive simulations and companion experiments are performed in order to quantify cell deformation and pressure-velocity relationships for different channel sizes and physiologically relevant temperatures. We discuss conditions associated with the shape transitions of RBCs along with the relative effects of membrane and cytosol viscosity, plasma environments, and geometry on flow through microfluidic systems at physiological temperatures. In particular, we identify a cross-sectional area threshold below which the RBC membrane properties begin to dominate its flow behavior at room temperature; at physiological temperatures this effect is less profound.

Peptide-activated double-negative T cells can prevent autoimmune type-1 diabetes development.

Autoimmune diseases may develop because of defective maturation, activation, differentiation and function of regulatory T cells. Previous studies have shown that exposure to donor antigen activates peripheral TCRalphabeta+CD3+CD4-CD8-NK1.1-, double-negative (DN) T cells, which specifically suppress anti-donor T cells and enhance survival of skin and heart grafts from allogeneic and xenogeneic donors. However, the role of DN T cells in preventing T cell-mediated autoimmune disease is unknown. Here, we analyzed the ability of DN T cells to recognize peptides expressed on self MHC and to suppress peptide-reactive CD8+ T cells, using the P14 mouse model that expresses a transgenic TCR specific for gp33 peptide presented on self MHC class I-Db. We found that injection of gp33 peptide resulted in increased DN and decreased CD8+ T cell numbers in the lymph nodes when compared to untreated mice. Injection of gp33, but not TCR-non-specific AV peptide, increased expression of T cell activation markers on DN T cells. Moreover, gp33-activated DN T cells suppressed proliferation of syngeneic CD8+ T cells via killing activated CD8+ T cells in an antigen-specific fashion in vitro. Furthermore, transferring gp33-activated DN T cells inhibited the development of autoimmune diabetes, suggesting that DN T cells may provide a novel therapy for T cell-mediated autoimmune diseases.

Entropic elasticity controls nanomechanics of single tropocollagen molecules.

We report molecular modeling of stretching single molecules of tropocollagen, the building block of collagen fibrils and fibers that provide mechanical support in connective tissues. For small deformation, we observe a dominance of entropic elasticity. At larger deformation, we find a transition to energetic elasticity, which is characterized by first stretching and breaking of hydrogen bonds, followed by deformation of covalent bonds in the protein backbone, eventually leading to molecular fracture. Our force-displacement curves at small forces show excellent quantitative agreement with optical tweezer experiments. Our model predicts a persistence length xi(p) approximately 16 nm, confirming experimental results suggesting that tropocollagen molecules are very flexible elastic entities. We demonstrate that assembly of single tropocollagen molecules into fibrils significantly decreases their bending flexibility, leading to decreased contributions of entropic effects during deformation. The molecular simulation results are used to develop a simple continuum model capable of describing an entire deformation range of tropocollagen molecules. Our molecular model is capable of describing different regimes of elastic and permanent deformation, without relying on empirical parameters, including a transition from entropic to energetic elasticity.

CD44 promotes resistance to apoptosis in murine colonic epithelium.

Dysregulated expression of CD44 isoforms occurs consistently in colon carcinogenesis, and this change occurs also in most other types of cancer. One of the basic features of malignant transformation is the acquisition of resistance to apoptosis. We previously found that the colonic epithelium of mice, deficient in CD44 is predisposed to apoptosis. In this study, we asked whether the expression of CD44 alters the response of the colon to an apoptotic stimulus, and what are the mechanisms involved. For this, we assessed the susceptibility of the murine colon to apoptosis by total body irradiation to induce apoptosis. Apoptotic and concomitant changes relevant to the mechanisms of apoptosis were monitored by molecular markers of apoptosis. We found enhanced susceptibility to apoptosis in CD44 deficient colonic epithelium based on an increase in the number of apoptotic bodies, and activation of caspase 3. This was not associated with alterations in proliferations as shown by comparable Ki-67 expression and BrdU labeling. Furthermore, upregulated active caspase 3 in CD44 deficient colon was accompanied by concomitant molecular alterations in caspase 9 and not caspase 8, and this indicated the involvement of the mitochondrial pathway in apoptosis execution. Overall, this is the first report demonstrating CD44 mediated resistance to apoptosis in the colonic epithelium in vivo. This implicates CD44 in promoting cell transformation into a malignant phenotype, in conjunction with other anti-apoptotic factors.