Simpson, N. | bioRxiv Science

bioRxiv2018

Immune profiling of cord blood after prolonged rupture of membranes.

We hypothesised that foetal immune responses to an infectious challenge may be detected by genome-wide transcriptional profiling of cord blood. In order to test this hypothesis, we sought to identify transcriptomic changes in post-natal cord blood samples following prolonged pre-labour rupture of membranes (PROM) as a surrogate for increased risk of infection. By comparison to controls we found increased levels of blood transcripts in a subset of prolonged PROM cases, significantly enriched for innate immune system signalling pathways. These changes were idiosyncratic, suggesting qualitative and quantitative variation in foetal immune responses which may reflect differences in exposure and/or in host genetics. Our data support the view that PROM represents an infection risk to the foetus. In addition, we propose that cord blood transcriptional profiling offers exciting opportunities to identify immune correlates of clinical outcome following potential in utero exposures to infection. These may be used to elucidate the mechanisms of immunological protection and pathology in the foetus and identify biomarkers to stratify the risk of adverse outcomes.

immunology↗

bioRxiv2017

Association of BDNF Val66Met Polymorphism and Brain BDNF levels with Major Depression and Suicide

BACKGROUND: Brain-derived neurotrophic factor (BDNF) is implicated in the pathophysiology of major depressive disorder (MDD) and suicide. Both are partly caused by early life adversity (ELA) and ELA reduces both BDNF protein and gene expression. This study examines the association of BDNF Val66Met polymorphism and brain BDNF levels with depression and suicide. We hypothesized that both major depression and ELA would be associated with the Met allele and lower brain BDNF levels. Such an association would be consistent with low BDNF mediating the effect of ELA on adulthood suicide and MDD. METHODS: BDNF Val66Met polymorphism was genotyped in postmortem brains of 37 suicide decedents and 53 non-suicides. Additionally, BDNF protein levels were determined by Western blot in dorsolateral prefrontal cortex (Brodmann area 9; BA9), anterior cingulate cortex (ACC; BA24), caudal brainstem and rostral brainstem. The relationships between these measures and major depression, death by suicide and reported childhood adversity were examined. RESULTS: Depressed subjects had an excess of the Met allele and lower BDNF levels in ACC and caudal brainstem compared with non-depressed subjects. No effect of history of suicide death or early life adversity was observed with genotype, but lower BDNF levels in ACC were found in subjects who had been exposed to early life adversity and/or died by suicide compared to nonsuicide decedents and no reported childhood adversity. CONCLUSIONS: This study provides further evidence for low BDNF in major depression related to the BDNF met risk allele. Future studies should seek to determine how altered BDNF expression contributes to MDD and suicide.

neuroscience↗