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Traumatic brain injury (TBI) is an established risk factor for neurodegenerative disorders and dementias. Epigenetic modifications, such as DNA methylation, may alter the expression of genes without altering the DNA sequence in response to environmental factors. We hypothesized that DNA methylation changes may occur in the injured human brain and be implicated in the neurodegenerative aftermath of TBI. The DNA methylation status of genes related to neurodegeneration, e.g. amyloid beta precursor protein (APP), microtubule associated protein tau (MAPT), neurofilament heavy (NEFH), neurofilament medium (NEFM) and neurofilament light (NEFL), was analyzed in fresh, surgically resected human brain tissue from 17 severe TBI patients and compared with brain biopsy samples from 19 patients with idiopathic normal pressure hydrocephalus (iNPH). We also performed an epigenome-wide association study (EWAS) comparing TBI patients to iNPH controls. Thirty-eight CpG sites in the APP, MAPT, NEFH and NEFL genes were differentially methylated by TBI. Among the top 20 differentially methylated CpG sites, 11 were in the APP gene. In addition, the EWAS evaluating 828 888 CpG sites revealed 308 differentially methylated CpG sites in genes related to cellular/anatomical structure development, cell differentiation and anatomical morphogenesis. These preliminary findings provide the first evidence of an altered DNA methylome in the injured human brain and may have implications for the neurodegenerative disorders associated at long-term with TBI. 

Background Migraine represents one of the most prevalent neurological conditions worldwide. It is a disabling condition with high impact on the working situation of migraineurs. Interestingly, gender-related differences regarding an association of migraine with important occupational characteristics has been hardly studied. Methods The current study scrutinizes gender-specific differences in the prevalence of migraine across a broad spectrum of occupational categories, shedding also light on associations with important job-related features such as shift work, job satisfaction, and physical activity. The study included data from 415 712 participants from the UK Biobank cohort, using the official ICD10 diagnosis of migraine and other health conditions as selection criteria. Prevalence ratios of migraineurs compared to healthy controls among different occupational categories and job-related variables were estimated using log-binomial regression analyses. Statistical models were adjusted for important sociodemographic features such as age, BMI, ethnicity, education and neuroticism. To better highlight specific differences between men and women we stratified by sex. Results We detected a differential prevalence pattern of migraine in relation to different job categories between men and women. Especially in men, migraine appears to be more prevalent in highly physically demanding occupations (PR 1.38, 95% CI [0.93, 2.04]). Furthermore, migraine is also more prevalent in jobs that frequently involve shift or night shift work compared to healthy controls. Interestingly, this prevalence is especially high in women (shift work PR 1.45, 95% CI [1.14, 1.83], night shift work PR 1.46, 95% CI [0.93, 2.31]). Conclusion Our results show that migraine is genderdependently associated with physically demanding jobs and shift working.

Background: Migraine and depression are highly prevalent and partly overlapping disorders that cause strong limitations in daily life. Patients tend to respond poorly to the therapies available for these diseases. OnabotulinumtoxinA has been proven to be an effective treatment for both migraine and depression. While many studies have addressed the effect of onabotulinumtoxinA in migraine or depression separately, a growing body of evidence suggests beneficial effects also for patients comorbid with migraine and depression. The current meta-analysis systematically investigates to what extent onabotulinumtoxinA is efficient in migraineurs with depression.

Methods: A systematic literature search was performed based on PubMed, Scopus and Web of Science from the earliest date till October 30th, 2020. Mean, standard deviation (SD) and sample size have been used to evaluate improvement in depressive symptoms and migraine using random- effects empirical Bayes model.

Results: Our search retrieved 259 studies, eight of which met the inclusion criteria. OnabotulinumtoxinA injections administered to patients with both chronic migraine and major depressive disorder led to mean reduction of - 8.94 points (CI [ - 10.04,- 7.84], p < 0.01) in the BDI scale, of - 5.90 points (CI [ - 9.92,- 1.88], p < 0.01) in the BDI-II scale and of - 6.19 points (CI [ - 9.52,- 2.86], p < 0.01) in the PHQ-9 scale, when evaluating depressive symptoms. In the case of the migraine-related symptoms, we found mean reductions of - 4.10 (CI [ - 7.31,- 0.89], p = 0.01) points in the HIT6 scale, - 32.05 (CI [ - 55.96,- 8.14], p = 0.01) in the MIDAS scale, - 1.7 (CI [ - 3.27,- 0.13], p = 0.03) points in the VAS scale and of - 6.27 (CI [ - 8.48,- 4.07], p < 0.01) migraine episodes per month. Comorbid patients showed slightly better improvements in BDI, HIT6 scores and migraine frequency compared to monomorbid patients. The latter group manifested better results in MIDAS and VAS scores.

Conclusion: Treatment with onabotulinumtoxinA leads to a significant reduction of disease severity of both chronic migraine and major depressive disorder in patients comorbid with both diseases. Comparative analyses suggest an equivalent strong effect in monomorbid and comorbid patients, with beneficial effects specifically seen for certain migraine features.

Aims Observational studies have suggested strong associations between sleep duration and many cardiovascular diseases (CVDs), but causal inferences have not been confirmed. We aimed to determine the causal associations between genetically predicted sleep duration and 12 CVDs using both linear and nonlinear Mendelian randomization (MR) designs. Methods and results Genetic variants associated with continuous, short (<= 6 h) and long (>= 9 h) sleep durations were used to examine the causal associations with 12 CVDs among 404 044 UK Biobank participants of White British ancestry. Linear MR analyses showed that genetically predicted sleep duration was negatively associated with arterial hypertension, atrial fibrillation, pulmonary embolism, and chronic ischaemic heart disease after correcting for multiple tests (P <0.001). Nonlinear MR analyses demonstrated nonlinearity (L-shaped associations) between genetically predicted sleep duration and four CVDs, including arterial hypertension, chronic ischaemic heart disease, coronary artery disease, and myocardial infarction. Complementary analyses provided confirmative evidence of the adverse effects of genetically predicted short sleep duration on the risks of 5 out of the 12 CVDs, including arterial hypertension, pulmonary embolism, coronary artery disease, myocardial infarction, and chronic ischaemic heart disease (P< 0.001), and suggestive evidence for atrial fibrillation (P < 0.05). However, genetically predicted long sleep duration was not associated with any CVD. Conclusion This study suggests that genetically predicted short sleep duration is a potential causal risk factor of several CVDs, while genetically predicted long steep duration is unlikely to be a causal risk factor for most CVDs. [GRAPHICS] .

Millions of people are currently on statin medications (HMGCR inhibitors) to prevent cardiovascular diseases. Despite considerable central nervous system expression, little is known about HMGCR function in the brain. In Paper I, we used Drosophila and rodent models and found that inhibiting Hmgcr expression in the insulin-producing cells of the Drosophila hypothalamus equivalent, known as the pars intercerebralis (PI), throughout development, significantly reduces the expression of Insulin–like peptides 2 and 3 (ILP2 and ILP3), severely decreasing insulin signalling. This reduction causes decreased body size, hyperglycemia, increased lipid storage, and hyperphagia. We also discovered that Farnesyl pyrophosphate synthase (Fpps), an enzyme downstream of Hmgcr in the mevalonate pathway, is required for ILP2 expression in the PI. In rodents, acute inhibition of hypothalamic Hmgcr stimulates food intake as well. Furthermore, in rats, we found two regions within the hypothalamus that had significantly increased neural activity, the paraventricular nucleus and arcuate nucleus, which are known to regulate food intake. In Paper II, we explored the effects of statins on cognition and performed an observational study on a population-based sample from the UK Biobank. Cognitive performance in terms of reaction time, working memory and fluid intelligence was analysed at baseline and two follow-ups. Subjects were classified depending on age (up to 65 and over 65 years). The effect of statin use differed between the two age groups, with a beneficial effect on reaction time in older persons and fluid intelligence in both age groups, and a negative effect on working memory in younger subjects. In Paper III, we examined association of single nucleotide polymorphisms within the HMGCR gene, rs17238484 and rs12916, with self-reported insomnia symptoms. We found that statin users are associated with a higher risk for self-reported insomnia. The HMGCR genetic variants were also associated with self-reported insomnia, but in different manner. Carriers the rs12916-T risk allele had a protective effect from insomnia symptoms. No associations were found for either statin takers or carriers of these HGCMR risk alleles and late evening chronotype. The increased risk of insomnia noted with statins is partially explained by a mechanism that might be independent of HMGCR inhibition. In Paper IV, we discovered a novel role for Hmgcr in sleep regulation in Drosophila, where lacking of pan-neuronal Hmgcr expression causes sleep-promoting effects. We also found that loss of Hmgcr expression specifically in the PI insulin-producing cells, recapitulates the effect of pan-neuronal Hmgcr inhibition. Conversely, inhibiting Hmgcr in only six PI DH44 expressing neurons has the opposite effect on sleep, increasing sleep latency and decreasing sleep duration. This bi-functional property of Hmgcr in the fly brain underlies its importance in sleep regulation. Furthermore, loss of Hmgcr showed no effect on circadian rhythm, suggesting that Hmgcr regulates sleep by pathways distinct from the circadian clock.

Importance: Statins have been linked to an increased risk for insomnia, but the literature is controversial. Moreover, it is unknown, if the potential effects are directly related to the inhibition of the statin target HMGCR, the subsequently lowered cholesterol levels, or other off-target effects of statins. Aims: To investigate the association of statin treatment and genetic proxies of cholesterol lowering drugs with the risk for insomnia and chronotype in a large population-based cohort. Methods: A cross-sectional cohort study based on baseline data collected between 2006–2010 in UK biobank cohort was conducted. European participants without any history of psychiatric/neurological disorders or of stroke and with available genetic data as well as information on statin use were included in the present study. Self-reported measures of insomnia and chronotype were analysed (a) in statin users versus control subjects, (b) subjects carrying single nucleotide polymorphisms (SNPs) in the HMGCR gene, which are associated with reduced enzymatic function and lower cholesterol levels (rs17238484 and rs12916) and (c) subjects carrying a SNP in the PCSK9 gene (rs1159147), which leads to lower cholesterol levels independent of HMGCR. The main analysis were performed using multivariable regression models. Statin treatment and SNPs in HMGCR and PCSK9 genes were used as exposures and main outcomes were insomnia and chronotype. Results: A total of 206,801participants (mean [SD] age, 57.5 [7.9] years; 56% women; 20% statin users) were included in the present study. Statin users had an increased risk of insomnia compared to controls (odds ratio [95% CI], 1.07 [1.03 to 1.11]; p = 1.42 × 10−4). A similar effect was observed for PCSK9 rs11591147-T allele (1.07 [1.01–1.14]; 0.014), while the two gene variants of HMGCR were associated with a reduced risk for insomnia (rs17238484-G: 0.97 [0.95 to 0.99]; 0.014 and rs12916-T: 0.97 [0.96 to 0.99]; 0.002). In regard to chronotype, there was no effect of either statin treatment or HMGCR SNPs, but the PCSK9 rs11591147-T allele was associated with a higher evening preference (1.17 [1.06 to 1.29]; 0.001). Conclusion: Our data suggests that statin treatment can pose an increased risk for insomnia in in the European population. Interestingly, there was no agreement between the effects of statins and the effects of reduced HMGCR activity based on genetic variants, suggesting that the observed unfavourable effect of statins on sleep is conveyed through other targets. This further explains why the literature on statin effects on sleep is not conclusive. Finally our data encourage further investigations into the molecular processes linking statins, HMGCR and PCSK9 to sleep behaviour.

Statins, HMG Coenzyme A Reductase (HMGCR) inhibitors, are a first-line therapy, used to reduce hypercholesterolemia and the risk for cardiovascular events. While sleep disturbances are recognized as a side-effect of statin treatment, the impact of statins on sleep is under debate. Using Drosophila, we discovered a novel role for Hmgcr in sleep modulation. Loss of pan-neuronal Hmgcr expression affects fly sleep behavior, causing a decrease in sleep latency and an increase in sleep episode duration. We localized the pars intercerebralis (PI), equivalent to the mammalian hypothalamus, as the region within the fly brain requiring Hmgcr activity for proper sleep maintenance. Lack of Hmgcr expression in the PI insulin-producing cells recapitulates the sleep effects of pan-neuronal Hmgcr knockdown. Conversely, loss of Hmgcr in a different PI subpopulation, the corticotropin releasing factor (CRF) homologue-expressing neurons (DH44 neurons), increases sleep latency and decreases sleep duration. The requirement for Hmgcr activity in different neurons signifies its importance in sleep regulation. Interestingly, loss of Hmgcr in the PI does not affect circadian rhythm, suggesting that Hmgcr regulates sleep by pathways distinct from the circadian clock. Taken together, these findings suggest that Hmgcr activity in the PI is essential for proper sleep homeostasis in flies.