Check out some of the papers that were recently published by DMCBH members:

Alexander Rauscher, David Li, Jack Taunton: Uncovering the hidden effects of repetitive subconcussive head impact exposure: A meta-analytic approach characterizing seasonal brain microstructural changes in contact and collision sports athletes 

Journal: Human Brain Mapping  

It is believed that repetitive subconcussive head impacts can induce brain injuries that are not detectable by clinical tests, potentially resulting in cumulative and long-term brain changes. The present study explored patterns of longitudinal brain white matter changes across sports where these head impacts often occur.  Data from a total of 131 non-concussed athletes in American football, rugby, and ice hockey with an average age of 20 was analyzed. One sample t-tests were applied to analyze differences between baseline and post-season data. The analyses revealed widespread lateralized patterns of sports-related increases and decreases in mean diffusivity, radial diffusivity, and axial diffusivity across distinct white matter regions. The patterns included the presence of strain-induced injuries in central and brainstem regions and mild physical exercise-induced effects across frontal and superior regions of the left hemisphere. The article also highlighted key considerations to enhance future work, improve comparability between studies, and promote data pooling initiatives.  

 

Kiran Soma: Steroid profiling in human primary teeth via liquid chromatography-tandem mass spectrometry for long-term retrospective steroid measurement

Journal: PLOS ONE  

Steroid hormones play an important role in a variety of physiological processes, and measurements of steroids in blood, saliva, and urine are widely used to assess irregularities. However, these measures cannot assess early-life stress or developmental pathologies well because they are not long-term. This study developed and validated the first assay to measure steroids in human baby teeth using liquid chromatography-tandem spectrometry. The assay is highly sensitive, specific, accurate, and precise, allowing for the simultaneous quantification of 17 steroids in baby teeth. Levels of dehydroepiandrosterone, cortisol, and progesterone were highest in this sample. In addition, no sex differences were found between males and females. This study proposed a novel way to quantify steroids from human baby teeth and retrospectively assess early-life stress and developmental endocrine pathologies. 

 

Fidel Vila-Rodriguez: Frontostriatal salience network expansion in individuals in depression 

Journal: Nature  

Depression is a diverse neuropsychiatric syndrome that is associated with connectivity alterations in frontostriatal networks which are related to reward processing and filtering external stimuli. Using precision fMRI, the researchers discovered that the frontostriatal salience network was expanded nearly twofold in individuals with depression. The effect was replicable in several samples and stable over time, even detectable in children before the onset of depression later in adolescence. This study identified a trait-like brain network that potentially confers risk for depression in frontostriatal circuits. 

 

Helen Tremlett: Investigation of health care use and a possible prodrome before the first attack in NMOSD and MOGAD 

Journal: Multiple Sclerosis Journal  

The study investigated the possibility of a prodromal phase, or pre-symptomatic period, in two autoimmune neurological conditions – aquaporin-4 antibody positive (AQP4+) neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein antibody disease (MOGAD). Using health administrative data in Ontario, Canada, the researchers compared outpatient visits and hospitalizations in the 5 years preceding the initial attack between patients with NMOSD and MOGAD. The results showed that for the NMOSD group, there was a significantly elevated rate of outpatient visits and hospitalizations in the 5 years before the initial attack, suggesting the presence of a prodromal phase. This pattern was not seen in the MOGAD group. This indicates the potential for earlier recognition and management of NMOSD patients before the first major attack occurs. 

 

Helen Tremlett: Updated Multiple Sclerosis Incidence, 2015-2022 

Journal: JAMA Neurology  

This cohort study examined the incidence of multiple sclerosis (MS) in Germany from 2015 to 2022 using nationwide outpatient claims data. The results showed that the annual number of incident MS cases remained stable, ranging from 9,507 (2019) to 10,633 (2021), with a consistent female predominance. The age- and sex-standardized cumulative MS incidence per 100,000 people declined slightly over the study period, which may be attributed to factors such as a growing population, immigration, and improved diagnostic sensitivity. The findings suggest that the incidence of MS in Germany has remained constant in recent years. 

 

Annie Ciernia: Repeated LPS induces training and tolerance of microglial responses across brain regions

Journal: Neuroinflammation  

Neuroinflammation plays a role in nearly every central nervous system disorder. Microglia, the brain’s immune cells, adjust their activity based on the brain’s environment. Prior research has shown that repeated inflammation can cause lasting changes in microglial gene expression and function. In this study, researchers gave mice multiple low doses of lipopolysaccharide (LPS) to examine the immediate effects on microglia in the frontal cortex, hippocampus, and striatum, as well as the long-term behavioural outcomes. The results showed that repeated LPS exposure altered microglial gene expression across brain regions, forming specific patterns related to biological functions. Morphological changes in microglia, including shifts in their shape and structure, were also observed. These findings suggest that microglia dynamically regulate immune memory in the brain, which could be relevant to brain diseases. 

 

Liisa Galea: Pregnancy history and estradiol influence spatial memory, hippocampal plasticity, and inflammation in middle-aged rats

Journal: Hormones and Behaviour

Pregnancy and motherhood can have long-term effects on cognition and brain aging. While estrogen may improve cognition in postmenopausal women, the evidence is mixed. Research shows that having a first pregnancy at a younger age is linked to poorer aging outcomes in humans. This study explored how the age at first pregnancy and estradiol levels impact hippocampal neuroplasticity, inflammation, cognition, and gene activity in rats. Older first-time mothers showed impaired spatial memory but improved reversal learning and more new neurons in the ventral hippocampus. Estradiol reduced neuron activity in the dorsal hippocampus and decreased anti-inflammatory markers, depending on maternal age. The study suggests that estradiol affects brain plasticity and inflammation in middle age and that maternal age at first pregnancy has lasting effects on the hippocampus. 

 

Judy Illes: Stepwise Imperatives for Improving the Protection of Animals in Research and Education in Canada

Journal: Animals  

Canada’s decentralized system for regulating animal use in science can weaken protections, cause confusion around compliance, and complicate enforcement. The present paper proposes a step-by-step approach to centralizing animal welfare laws, starting with the enhancement of the current 3Rs framework (Replacement, Refinement, and Reduction) by adding two more: Reflection and Responsiveness. These new Rs promote continuous evaluation of research, timely action based on new findings, and the publication of all data. By adopting all five Rs, animal welfare in scientific research across Canada could improve immediately and serve as a model for other countries.