Jana Tuusov

Genetic association studies have implicated neural adhesion-related genes in suicidal behaviour and related psychiatric phenotypes, whereas postmortem brain transcriptomic studies have yielded heterogeneous findings with limited support after multiple-testing correction. We synthesized genetic evidence and examined IgLON expression in bilateral anterior midcingulate cortex (aMCC) samples from 14 suicide and 10 non-suicide donors. RT-qPCR measured eight transcripts from five IgLON genes, including alternative promoter-derived transcripts of LSAMP, NTM and OPCML. We additionally reanalysed published dorsolateral prefrontal cortex (DLPFC) expression data and examined public transcriptomic datasets. The genetic synthesis identified several adhesion-related candidate genes, while exploratory DLPFC reanalysis suggested potentially informative promoter-specific differences in LSAMP expression. In the aMCC, NEGR1 expression was lower in the right hemisphere of suicide donors (suicide/non-suicide ratio = 0.54; FDR-adjusted q = 0.027), but not significantly different in the left. Directional NEGR1 asymmetry also differed between groups (q = 0.026), although this result was sensitive to covariate adjustment and the scope of multiple-testing correction. Blood ethanol adjustment minimally changed effect estimates. No other aMCC transcript or public transcriptomic comparison showed FDR-significant differences. Our findings support anatomically focused, bilateral and transcript-specific investigation of neural adhesion genes in larger, independent cohorts.

Alcohol can induce diverse serious pathologies, yet this complexity may be obscured when alcohol-related deaths are classified according to a single underlying cause. We sought to quantify this issue and its implications for analysing mortality data. Cross-sectional study included 554 men aged 25-54 in Estonia undergoing forensic autopsy in 2008-09. Potentially alcohol-related pathologies were identified following macroscopic and histological examination. Alcohol biomarkers levels were determined. For a subset (26%), drinking behaviour was provided by next-of-kin. The Estonian Statistics Office provided underlying cause of death. Most deaths (75%) showed evidence of potentially alcohol-related pathologies, and 32% had pathologies in two or more organs. The liver was most commonly affected [60.5%, 95% confidence interval (CI) = 56.3-64.6] followed by the lungs (18.6%, 95% CI = 15.4-22.1), stomach (17.5%, 95% CI = 14.4-20.9), pancreas (14.1%, 95% CI = 11.3-17.3), heart (4.9%, 95% CI = 3.2-7.0) and oesophagus (1.4%, 95% CI = 0.6-2.8). Only a minority with liver pathology had a second pathology. The number of pathologies correlated with alcohol biomarkers (phosphatidylethanol, gamma-glytamyl transpeptidase in blood, ethylglucuronide, ethylsulphate in urine). Despite the high prevalence of liver pathology, few deaths had alcoholic liver disease specified as the underlying cause. The majority of 554 men aged 25-54 undergoing forensic autopsy in Estonia in 2008-09 showed evidence of alcohol-related pathology. However, the recording of deaths by underlying cause failed to capture the scale and nature of alcohol-induced pathologies found.

Alcohol makes an important contribution to premature mortality in many countries in Eastern Europe, including Estonia. However, the full extent of its impact, and the mechanisms underlying it, are challenging issues to research. We describe the design and initial findings of a study aimed at investigating the association of alcohol with mortality in a large series of forensic autopsies of working-age men in Estonia. 1299 male deaths aged 25-54 years were subject to forensic autopsy in 2008-2009. The routine autopsy protocol was augmented by a more systematic inspection of organs, drug testing, assay of liver enzymes and novel biomarkers of alcohol consumption (EtG, EtS and PEth), together with proxy interviews with next of kin for deaths among men who lived in or close to a major town. 595 augmented autopsies were performed. Of these, 66% were from external causes (26% suicide, 25% poisoning). 17% were attributed to circulatory system diseases and 7% to alcoholic liver disease. Blood alcohol concentrations (BAC) of ≥ 0.2 mg/g were found for 55% of deaths. Interviews were conducted with proxy informants for 61% of the subjects who had resided in towns. Of these, 28% were reported in the previous year to have been daily or almost daily drinkers and 10% had drunk non-beverage alcohols. Blood ethanol and the liver enzyme GGT were only associated with daily drinking. However, the novel biomarkers showed a more graded response with recent consumption. In contrast, the liver enzymes AST and ALT were largely uninformative because of post-mortem changes. The presence of extremely high PEth concentrations in some samples also suggested post-mortem formation. We have shown the feasibility of deploying an extended research protocol within the setting of routine forensic autopsies that offer scope to deepen our understanding of the alcohol-related burden of premature mortality. The most unique feature of the study is the information on a wide range of informative alcohol biomarkers, several of which have not been used previously in this sort of post-mortem research study. We have demonstrated, for the first time, the epidemiological value and validity of these novel alcohol biomarkers in post-mortem samples.