👤 Mikael Rydén

Cognitive outcomes following brain insult are shaped by a range of factors, including genetic predispositions. Emerging evidence indicates that specific genetic variants may affect the susceptibility to cognitive impairment in individual patients. In this systematic review we summarize the evidence for genetic variants on cognitive outcomes following brain insults. A systematic search was conducted in PubMed, Embase, PsycINFO, bioRxiv, medRxiv, reference lists, and ClinicalTrials.gov to identify studies published before June 14, 2023, reporting associations between genetic variants and cognitive outcomes following brain insults. Only studies conducted in humans and published in English were included. A broad definition of brain insults was applied, with a primary focus on stroke, traumatic brain injury (TBI), and brain tumors. All articles underwent bias assessment using the JBI critical appraisal tools. Of the 121 studies included, 80 (66%) were rated as low risk of bias. The APOE gene was investigated in 56% of TBI studies, 52% of stroke studies, and 43% of studies on other brain injuries. Of the 74 studies on APOE, 50 (68%) focused on the ε4 allele, with 39 studies (87%) reporting associations between the ε4 allele and worse cognitive outcomes. The BDNF rs6265 polymorphism was examined in 18 studies, 15 of which reported significant effects on cognitive outcomes. However, the direction of these effects was inconsistent, with seven studies linking the G allele and seven the A allele to worse cognitive outcomes. For the COMT rs4680 polymorphism, nine out of 12 studies reported worsened cognitive outcomes linked to the G allele, while several reported a protective association for the A allele. Injury- and population-specific patterns were not consistent. This systematic review suggests that APOE-ε4 and potentially the G allele of COMT rs4680 are associated with poor cognitive outcomes following brain insults. The type of brain injury does not appear to influence whether genetic variants predispose to favorable or unfavorable cognitive outcomes. Future research may benefit from focusing on these markers, particularly in larger datasets, to validate these findings. Show less

Women face greater vulnerability to dementia and Alzheimer's disease (AD), potentially due to estrogen fluctuations across the lifespan. However, its role in vascular brain health is unclear. We investigated associations between lifelong estrogen exposure-endogenous (reproductive span) and exogenous (oral contraceptives [OC], menopausal hormone therapy [MHT])-and late-life vascular brain injury, AD-related atrophy, and We included 352 cognitively unimpaired 70-years-old women from the Gothenburg H70-1944 Birth Cohort with brain MRI and 5-year follow-up. Reproductive lifespan was calculated as age at menopause or oophorectomy minus age at menarche. OC and MHT use were self-reported. Outcomes included cerebral small vessel disease (SVD), AD-related cortical thickness, and white-matter integrity (fractional anisotropy). Linear and multinomial regression and mixed-effects models were adjusted for confounders and stratified by Extended estrogen exposure throughout life-both endogenous and exogenous-appear to support late-life cerebrovascular health in women, with potential genotype-specific neuroprotective effects. Given the current absence of sex-specific prevention guidelines for cognitive disorders, future research should clarify estrogen's longterm impact on brain health and cognition to inform personalized medicine. Show less

Nearly 90 clinicians and researchers from around the world attended the first IMPROVE 2022 International Meeting on Pathway-Related Obesity. Delegates attended in person or online from across Europe, Argentina and Israel to hear the latest scientific and clinical developments in hyperphagia and severe, early-onset obesity, and set out a vision of excellence for the future for improving the diagnosis, treatment, and care of patients with melanocortin-4 receptor (MC4R) pathway-related obesity. The meeting co-chair Peter Kühnen, Charité Universitätsmedizin Berlin, Germany, indicated that change was needed with the rapidly increasing prevalence of obesity and the associated complications to improve the understanding of the underlying mechanisms and acknowledge that monogenic forms of obesity can play an important role, providing insights that can be applied to a wider group of patients with obesity. World-leading experts presented the latest research and led discussions on the underlying science of obesity, diagnosis (including clinical and genetic approaches such as the role of defective MC4R signalling), and emerging clinical data and research with targeted pharmacological approaches. The aim of the meeting was to agree on the questions that needed to be addressed in future research and to ensure that optimised diagnostic work-up was used with new genetic testing tools becoming available. This should aid the planning of new evidence-based treatment strategies for the future, as explained by co-chair Martin Wabitsch, Ulm University Medical Center, Germany. Show less

Impaired adipose tissue insulin signalling is a critical feature of insulin resistance. Here we identify a pathway linking the lipolytic enzyme hormone-sensitive lipase (HSL) to insulin action via the glucose-responsive transcription factor ChREBP and its target, the fatty acid elongase ELOVL6. Genetic inhibition of HSL in human adipocytes and mouse adipose tissue results in enhanced insulin sensitivity and induction of ELOVL6. ELOVL6 promotes an increase in phospholipid oleic acid, which modifies plasma membrane fluidity and enhances insulin signalling. HSL deficiency-mediated effects are suppressed by gene silencing of ChREBP and ELOVL6. Mechanistically, physical interaction between HSL, independent of lipase activity, and the isoform activated by glucose metabolism ChREBPα impairs ChREBPα translocation into the nucleus and induction of ChREBPβ, the isoform with high transcriptional activity that is strongly associated with whole-body insulin sensitivity. Targeting the HSL-ChREBP interaction may allow therapeutic strategies for the restoration of insulin sensitivity. Show less

The Liver X receptor (LXR) is an important regulator of carbohydrate and lipid metabolism in humans and mice. We have recently shown that activation of LXR regulates cellular fuel utilization in adipocytes. In contrast, the role of LXR in human adipocyte lipolysis, the major function of human white fat cells, is not clear. In the present study, we stimulated in vitro differentiated human and murine adipocytes with the LXR agonist GW3965 and observed an increase in basal lipolysis. Microarray analysis of human adipocyte mRNA following LXR activation revealed an altered gene expression of several lipolysis-regulating proteins, which was also confirmed by quantitative real-time PCR. We show that expression and intracellular localization of perilipin1 (PLIN1) and hormone-sensitive lipase (HSL) are affected by GW3965. Although LXR activation does not influence phosphorylation status of HSL, HSL activity is required for the lipolytic effect of GW3965. This effect is abolished by PLIN1 knockdown. In addition, we demonstrate that upon activation, LXR binds to the proximal regions of the PLIN1 and HSL promoters. By selective knock-down of either LXR isoform, we show that LXRα is the major isoform mediating the lipolysis-related effects of LXR. In conclusion, the present study demonstrates that activation of LXRα up-regulates basal human adipocyte lipolysis. This is at least partially mediated through LXR binding to the PLIN1 promoter and down-regulation of PLIN1 expression. Show less