Tag Archives: publication

Genetic influence on cardiovascular reactivity

In a new study recently published in Psychosomatic Medicine, PredSL PI Harold Snieder and co-workers investigated the genetic and environmental architecture of blood pressure and underlying hemodynamics at rest and during stress in two ethnic groups. Cardiovascular measures obtained during both conditions showed substantial heritability indices that were comparable between individuals of African and European descent. Most of the variance in both resting and stress levels was found to be explained by common genetic factors, although other genetic factors that only contribute to cardiovascular levels during stress were also found to be important.

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Study Identifies New Gene Variations Associated With Heart Rate

New genetic variations associated with heart rate have been identified in a collaborative genome-wide study in which 268 researchers from 211 institutions, as well as six large research consortia joined forces. PredSL PI Harold Snieder contributed to this study. Since heart rate is a marker of cardiovascular health, researchers anticipated that a better understanding of its genetic regulation might provide a first step towards identifying targets for new drugs to treat cardiovascular disease. The study titled, “Identification of Heart Rate-Associated Loci and Their Effects on Cardiac Conduction and Rhythm Disorders,” was published online last week in the April issue of Nature Genetics.

To gain new insights into the genetic regulation of heart rate, the rseearchers spent three years working on a genome-wide association study using data from 181,171 participants from 65 studies during 2009-2012.  This effort resulted in the discovery of 14 new genetic variations that are associated with heart rate. Without any prior hypothesis, the entire human genome was studied, hoping to identify new genetic variations that no one before had even imagined would play a role in the regulation of heart rate. Experimental down-regulation of gene expression was then conducted on fruit flies and zebrafish, to better understand how genetic variations might affect heart rate. These experiments identified 20 genes with a role in heart rate regulation, signal transmission, embryonic development of the heart, as well cardiac disorders, such as dilated cardiomyopathy, congenital heart failure and sudden heart failure. The findings in humans as well as in fruit flies and zebrafish provide new insights into mechanisms that regulate heart rate.

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Changes in DNA methylation in hypertension

On 11 jan 2013 a new paper from PredSL PI Harold Snieder and collaborators was published in the journal PLOS ONE entitled “A Genome-Wide Methylation Study on Essential Hypertension in Young African American Males. After Snieder’s group published the first epigenome-wide association study (EWAS) of obesity in 2010 this is now also the very first study of its kind investigating hypertension. They conclude that identification of a difference in a blood leukocyte DNA methylation site between hypertensive cases and normotensive controls suggests that changes in DNA methylation may play an important role in the pathogenesis of hypertension. The age dependency of the effect further suggests complexity of epigenetic regulation in this age-related disease.

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Cochrane review on interventions to facilitate return to work

PredSL PI Ute Bültmann contributed to a Cochrane Review on interventions to facilitate return to work in adults with adjustment disorders that was published today.

Adjustment disorders are a frequent cause of sick leave and various interventions have been developed to expedite the return to work (RTW) of individuals on sick leave due to adjustment disorders. The review assesses the effects of interventions facilitating RTW for workers with acute or chronic adjustment disorders and discusses results from nine studies reporting on 10 psychological interventions and one combined intervention in 1546 participants.

 

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Cortisol and anxiety and depressive problems – results from TRAILS

PredSL PI Catharina Hartman contributed to  a study – that was published today in Psychoneuroendocrinology – on the relationship between anxiety and depressive problems and hypothalamic-pituitary-adrenal (HPA)-axis activity (cortisol in the morning). The study was executed in children from the TRAILS study, a general population and clinic-referred cohort.

Anxiety and depressive problems have often been related to higher hypothalamic-pituitary-adrenal (HPA)-axis activity (basal morning cortisol levels and cortisol awakening response [CAR]) and externalizing problems to lower HPA-axis activity. However, associations appear weaker and more inconsistent than initially assumed. Previous studies from TRAILS suggested sex-differences in these relationships and differential associations with specific dimensions of depressive problems in a general population sample of children (10-12 years). Using the TRAILS population sample (n=1604), the authors found most support for higher cortisol (mainly CAR) in relation to depressive problems. However, in general, associations were weak. Therefore, the present results shed doubt on the relevance of single day cortisol measurements for problem behaviors in the milder range. Associations may be stronger in more severe or persistent psychopathology.

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Older brains communicate differently

Ageing makes the networks in our brain less specific. Linda Geerligs, one of PredSL PI Natasha Maurits’ PhD students, used connectivity analysis of fMRI results to prove that the connections in our brain change as we grow older.

When compared with their younger counterparts, connectivity in the brain networks of older people decreases, while connectivity between brain networks increases. Linda also found evidence to suggest that the decrease in connectivity in the brain networks corresponds with slower reaction times and declining memory among the elderly. The research findings have been published online in Human Brain Mapping today.

The insights provided by this kind of fundamental research are very interesting. If we can discover exactly what changes in the brain during the ageing process and what the effects of these changes are, this will give us new leads for finding new treatments for elderly people with concentration and memory problems.

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Increased beta band phase locking compensates for decreased inhibition in elderly?

Today, Linda Geerligs, PhD student in Experimental Psychology and supervised by Monicque Lorist and PredSL PI Natasha Maurits, published a paper in the Journal of Cognitive Neuroscience on the effects of age on the suppression of irrelevant information.

The extent of decline of inhibitory functions with age is highly variable between individuals. In this study, Linda used event-related potentials (ERPs) and phase locking analyses to investigate neural correlates of this variability in inhibition between individuals. Older and younger participants performed a selective attention task in which relevant and irrelevant information was presented simultaneously. The participants were split into high and low performers based on their level of inhibition inefficiency, that is, the slowing of reaction times induced by information that participants were instructed to ignore. Efficient inhibition in both age groups was related to increased functional connectivity in the alpha band between frontal and occipito-parietal areas in the prestimulus interval. In addition, increased power in the alpha band in occipito-parietal areas was related to better inhibition both before and after stimulus onset. Phase locking in the upper beta band before and during stimulus presentation between frontal and occipito-parietal regions was related to better performance in older participants only, suggesting that this is an active compensation mechanism employed to maintain adequate performance. In addition, increased top-down modulation and increased power in the alpha band appears to be a general mechanism facilitating inhibition in both age groups.

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