Biology subjects

Cullell, N.

Publications and source records attributed to Cullell, N..

3 recordsLinked to original sources

bioRxiv2025

Biological age acceleration is more prevalent in men than in women at time of spontaneous intracerebral hemorrhage

ObjectiveSpontaneous intracerebral hemorrhage (ICH) occurs later in life in women compared to men. Although previous studies have demonstrated epigenetic age acceleration (EAA) differences in ischemic stroke (IS) patients - a measure of an individuals biological aging -it remains unknown whether this sex dimorphism also applies to ICH patients. Approach and ResultsWe joined two ICH cohorts (N= 200, 45% women: 76.8{+/-}13 years; 55% men: 67.9{+/-}14 years). DNAm levels were obtained from whole blood samples using Illumina EPIC array. We evaluated three age-predictor clocks (Horvath, Hannum and Zang-BLUP) and one health-status clock (Levine) and their respective EAA metrics including extrinsic EAA (EEAA) and intrinsic EAA (IEAA) measures. We compared aging measures between women and men, then performed an ICH-subtype stratification, a specificity analysis evaluating sex differences in non-stroke samples (N= 350, 54% women 60.8{+/-}8 years, men: 60.8{+/-}10 years) and replication of previous result in a new IS cohort (N= 657, 43% women 73.6{+/-}12 years, men: 70.1{+/-}11 years). Women at time of ICH present lower EAA values than men (Horvath-EAA, p-value=1x10-04; Hannum-EAA, p-value=8.1x10-06; BLUP-EAA, p-value=4.4x10-04) as well as lower extrinsic EAA values (Horvath-IEAA, p-value=3.1x10-03; Hannum-IEAA, p-value=6.5x10-04). These differences seemed to be driven by differences in deep-ICH patients. Non-ICH females have lower acceleration values (Hannum-EAA: -10,37) than non-ICH men (Hannum-EAA: -8,01), but the differences are smaller than in ICH cases (ICH-women Hannum-EAA: -9,26, ICH-men Hannum-EAA: -2,6). This pattern was consistent in the IS cohort, where women were chronologically older than men but had similar biological age and significantly lower epigenetic age acceleration across multiple measures (Horvath-EAA, p = 2.6x10-3; Hannum-EAA, p = 7.1x10-3; Horvath-IEAA, p = 1.6x10-2; Hannum-IEAA, p = 4.5x10-2). ConclusionThis study shows that biological age difference between women and men are not exclusive of ischemic stroke but also observed in ICH.

neuroscience↗

bioRxiv2024

Glymphatic system health in early Alzheimer's disease and its relationship to sleep, cognition and CSF biomarkers.

BACKGROUNDThe glymphatic system is thought to facilitate waste clearance from the brain during sleep. Impairment in this system may underpin the elevated deposition of pathological proteins in neurodegenerative conditions like Alzheimers disease (AD). Putative glymphatic system activity has been measured with contrast-enhanced, serial MRI, revealing slower clearance in people who are sleep deprived. It is important that these methods are used to understand changes to glymphatic function in people with early-stage AD. METHODSTwenty-four individuals with mild cognitive impairment were recruited. N=20 had CSF biomarker data, with 16 meeting criteria for AD positivity (AD+). Participants underwent polysomnography, cognitive testing and serial T1 MRI with intravenous gadolinium-based contrast agent, diffusion tensor imaging along the perivascular space (DTI-ALPS index), and core AD CSF biomarkers collection. Rate (over 24hrs) and efficiency (the amount of tracer cleared after 28hrs relative to uptake after 4hrs) of GCBA clearance were measured. RESULTSFaster/more efficient GBCA clearance was associated with shorter sleep latency. In AD+ participants faster 24hr clearance of GBCA was associated with a lower ratio of A{beta}1-42/A{beta}1-40 in the CSF. In addition, better clearance efficiency was associated with greater levels of A{beta}1-40, lower levels of A{beta}-1-42, and a smaller ratio of A{beta}1-42/A{beta}1-40 in the CSF. Higher DTI-ALPS indicated better cognitive performance and, unexpectedly, higher tau levels. However, it was not associated with GCBA clearance. CONCLUSIONSWe show, for the first time in humans, that glymphatic system function is associated with AD-related changes to sleep, cognition and core AD biomarker concentrations in CSF. However, for AD biomaker concentrations, these relationships are not in the expected direction: higher concentrations and lower A{beta}1-42/A{beta}1-40 ratio were associated with faster or more efficient clearance of GCBA. We suggest that increased neurodegeneration in those with elevated levels of tau and A{beta}1-40 may paradoxically increase glymphatic activity locally to brain regions with more atrophy relative to less, but not in a way that improves sleep or cognition. In fact, larger extracellular spaces may exacerbate the spread of tau via the glymphatic system and therefore accelerate the progression of AD.

neuroscience↗

bioRxiv2019

Identification of 20 novel loci associated to ischemic stroke. Epigenome-Wide Association Study

RationaleDNA methylation is dynamic, varies throughout the life course, and its levels are influenced by lifestyle and environmental factors, as well as by genetic variation. The leading genetic variants at stroke risk loci identified to date explain roughly 1-2% of stroke heritability. Most of these single nucleotide polymorphisms are situated within a regulatory sequence marked by DNase I hypersensitivity sites, which would indicate involvement of an epigenetic mechanism. ObjectiveTo detect epigenetic variants associated to stroke occurrence and stroke subtypes. Methods and ResultsA two-stage case-control epigenome-wide association study was designed. The discovery sample with 401 samples included 218 ischemic stroke (IS) patients, assessed at Hospital del Mar (Barcelona, Spain) and 183 controls from the REGICOR cohort. In two independent samples (N=226 and N=166), we replicated 22 CpG sites differentially methylated in IS in 21 loci, including 2 CpGs in locus ZFHX3, which includes known genetic variants associated with stroke. The pathways associated to these loci are inflammation and angiogenesis. The meta-analysis identified 384 differentially methylated CpGs, including loci of known stroke and vascular risk genetic variants, enriched by loci involved in lipid metabolism, adipogenesis, circadian clock, and glycolysis pathways. Stratification analysis by stroke subtypes revealed distinct methylation patterns. ConclusionsWe identified a set of 22 CpGs in 21 loci associated with IS. Our analysis suggests that DNA methylation changes may contribute to orchestrating gene expression that contributes to IS.

genetics↗