Biology subjects

Juster, R.-P.

Publications and source records attributed to Juster, R.-P..

3 recordsLinked to original sources

bioRxiv2026

Sex-related structural alterations across common epilepsies: a worldwide ENIGMA study

Epilepsy is characterized by widespread structural brain alterations extending beyond the epileptic zone, involving both cortical and subcortical regions. Importantly, the clinical manifestation of epilepsy, including seizure types, psychiatric comorbidities, and treatment responses, has been shown to differ between sexes. However, sex differences in structural alterations in epilepsy have been seldomly reported in neuroimaging studies, partly due to limited sample sizes and single-center designs. Here, we systematically investigated sex differences in common epilepsies and their related clinical variables using structural neuroimaging biomarkers in an international multi-center cohort of 1,253 epilepsy patients and 1,077 healthy controls. We studied cortical thickness and subcortical volume in two types of epilepsy: temporal lobe epilepsy (TLE) and genetic generalized epilepsy (GGE). Both male and female patients with TLE showed widespread cortical and subcortical thinning compared with controls. In GGE, when compared separately to controls, male patients showed only subtle structural alterations, whereas female patients exhibited more widespread structural alterations. Sex-stratified analyses revealed some variation in the extent and distribution of cortical thickness and subcortical volume alterations between male and female patients in both epilepsy cohorts. Yet, we did not find significant sex-by-diagnosis interaction effects in TLE and GGE. Similarly, no significant interaction effects were observed between sex and age of onset or disease duration in either patient group. Overall, although we observed some differences in regional cortical thickness and subcortical volume between male and female patients with epilepsy, we did not find significant sex-by-diagnosis interactions. Our findings indicate that sex differences in behavioral and clinical outcomes of epilepsy may involve biological or functional processes that require further investigation.

neuroscience↗

bioRxiv2025

Biopsychosocial Correlates of Resting and Stress-Reactive Salivary GDF15: Preliminary Findings

Growth differentiation factor 15 (GDF15) is a biomarker of energetic stress related to aging, disease, and mitochondrial defects. We recently showed that GDF15 is quantifiable in saliva and acutely inducible by psychosocial stress. To date, the associations between GDF15 and biopsychosocial factors and individual characteristics remain unknown. Here, in a sample of healthy working adults (n = 198, 70% females), we first confirmed that salivary GDF15 reacts to acute psychosocial stress, peaking 10 min following a socio-evaluative stress paradigm (+28.3%, g = 0.50, p < 0.0001). We then explored associations between i) baseline GDF15 and ii) GDF15 stress reactivity and a variety of trait- and state-level biopsychosocial factors including sex and gender characteristics; measures of mental health, stress, and burnout; physical health and health behaviors; and anthropometric and blood-based metabolic biomarkers. Baseline salivary GDF15 was higher in men than in women and was positively correlated with testosterone, while negatively correlated with estrogen and traditionally feminine gender roles. Of the psychosocial factors examined, we found that work-related stress variables were most consistently related to GDF15, with work-related cynicism, burnout, and emotional exhaustion predicting higher GDF15 reactivity, while job-related autonomy and utilization of competence predicted smaller GDF15 responses. Consistent with GDF15s induction in metabolic and renal diseases, baseline GDF15 was also positively correlated with indirect markers of metabolic disease including waist-to-hip ratio, creatinine, and albumin. Finally, participants with greater GDF15 reactivity also exhibited greater cortisol reactivity, consistent with the role of GDF15 in stress regulation and energy mobilization. Together, this exploratory analysis of salivary GDF15 suggest new biological and psychosocial correlates, calling for large-scale studies connecting human experiences with biological markers of energetic stress.

physiology↗

bioRxiv2024

Psychobiological regulation of plasma and saliva GDF15 dynamics in health and mitochondrial diseases

Growth Differentiation Factor 15 (GDF15) is a protein that reflects mitochondrial energetic stress and is linked to physical and mental health symptoms, aging, and mortality. Here, we tested the hypothesis that GDF15 is a stress-responsive biomarker through a series of observational and experimental studies. We report four main findings. First, in the UK Biobank (n=53,026) and Framingham Heart Study (FHS) Offspring (n=3,460) cohorts, plasma GDF15 levels were elevated in individuals with symptoms of depression and anxiety. In the FHS cohort, GDF15 was also higher in participants exposed to chronic psychosocial stressors, including lower educational attainment, lower family income, and higher job strain. Second, plasma GDF15 levels in the FHS cohort correlated positively with epigenetic clocks measuring biological aging and effect sizes of GDF15 associations with psychosocial stressors were comparable to those observed for the clocks. Third, in a two-participant intensive-sampling study (n=112 days), saliva GDF15 showed a robust awakening response similar to established stress-related hormones. However, it exhibited a distinct negative pattern, peaking at waking and declining by 42-92% within 30-45 minutes. Finally, in two laboratory experiments (n=148), acute social-evaluative stress significant increased GDF15 levels in plasma and saliva within minutes. Together, these findings suggest that psychosocial stress may contribute to mitochondrial energetic stress indexed by GDF15, with implications for aging and health. This work opens new avenues for using GDF15 as a non-invasive biomarker to study the biological embedding of stress and its impact on aging trajectories. Significance statementGrowth Differentiation Factor 15 (GDF15) is a circulating protein elevated with mitochondrial energetic stress, aging, and diseases. Our findings show that GDF15 is elevated with depressive and anxiety symptoms and in those exposed to chronic psychosocial stress. Elevated plasma GDF15 also correlates with accelerated biological aging, as measured by epigenetic clocks. The effect sizes linking GDF15 to psychosocial stressors were comparable to those observed for the epigenetic clocks. Saliva GDF15 shows a robust negative awakening response characterized by elevated levels at awakening before declining within 30-45 minutes. Acute social-evaluative stress induced increase in plasma and saliva GDF15. Together, these findings suggest GDF15 can be used to study the energetic mechanisms for the biological embedding of stress across the lifespan.

physiology↗