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- ItemDeveloping a quantitative method to assess the decomposition of embalmed human cadavers(Elsevier B.V., 2020-03-29) Balta, Joy Y.; Blom, Giorgio; Davidson, Alison; Perrault, Katelynn; Cryan, John F.; O'Mahony, Siobhain M.; Cassella, John P.Embalmed human cadavers are an essential educational tool in forensic science and medicine. Cadavers are often embalmed to extend the period they can be used. Qualitative observations such as odours, tissue texture and colour are the only methods currently used by anatomists to assess the decomposition progress of embalmed cadavers. The aim of this study was to provide a first proof-of-concept to determine whether methylamine, putrescine, and cadaverine could be detected and monitored over time from embalmed human tissues. The hypothesis was that these three compounds would exhibit temporal trends to quantitate progress of decomposition in embalmed cadavers. Two human cadavers were embalmed using McGown solution and liver samples were analysed over 35 days. Liver samples were extracted, homogenised and derivatised to quantify the presence of methylamine, cadaverine and putrescine by gas chromatography - mass spectrometry. All three amines were detected in the tissue samples throughout the duration of the study. Both cadavers had elevated methylamine levels over putrescine and cadaverine at early stages postmortem. This was followed by peaking and reducing in different patterns by the two cadavers; however, the three compounds from a single cadaver changed in a similar pattern. The proposed experimental procedure provides a foundation for further development of quantitative biogenic amine methods to determine decomposition progress in embalmed human cadavers.
- ItemMicrobiota‐gut‐brain axis as a regulator of reward processes(John Wiley & Sons, Inc., 2020-12-25) García-Cabrerizo, Rubén; Carbia, Carina; O´Riordan, Kenneth J.; Schellekens, Harriet; Cryan, John F.; Horizon 2020; Science Foundation IrelandOur gut harbours trillions of microorganisms essential for the maintenance of homeostasis and host physiology in health and disease. In the last decade, there has been a growing interest in understanding the bidirectional pathway of communication between our microbiota and the central nervous system. With regard to reward processes there is accumulating evidence from both animal and human studies that this axis may be a key factor in gating reward valence. Focusing on the mesocorticolimbic pathway, we will discuss how the intestinal microbiota is involved in regulating brain reward functions, both in natural (i.e. eating, social or sexual behaviours) and non-natural reinforcers (drug addiction behaviours including those relevant to alcohol, psychostimulants, opioids and cannabinoids). We will integrate preclinical and clinical evidence suggesting that the microbiota-gut-brain axis could be implicated in the development of disorders associated with alterations in the reward system and how it may be targeted as a promising therapeutic strategy.
- ItemA biological framework for emotional dysregulation in alcohol misuse: from gut to brain(Springer Nature Ltd., 2020-12-07) Carbia, Carina; Lannoy, Séverine; Maurage, Pierre; López-Caneda, Eduardo; O'Riordan, Kenneth J.; Dinan, Timothy G.; Cryan, John F.; Horizon 2020; Belgian American Educational Foundation; Fonds De La Recherche Scientifique - FNRS; Fundação para a Ciência e a TecnologiaAlcohol use disorder (AUD) has been associated with impairments in social and emotional cognition that play a crucial role in the development and maintenance of addiction. Repeated alcohol intoxications trigger inflammatory processes and sensitise the immune system. In addition, emerging data point to perturbations in the gut microbiome as a key regulator of the inflammatory cascade in AUD. Inflammation and social cognition are potent modulators of one another. At the same time, accumulating evidence implicates the gut microbiome in shaping emotional and social cognition, suggesting the possibility of a common underlying loop of crucial importance for addiction. Here we propose an integrative microbiome neuro-immuno-affective framework of how emotional dysregulation and alcohol-related microbiome dysbiosis could accelerate the cycle of addiction. We outline the overlapping effects of chronic alcohol use, inflammation and microbiome alterations on the fronto-limbic circuitry as a convergence hub for emotional dysregulation. We discuss the interdependent relationship of social cognition, immunity and the microbiome in relation to alcohol misuse- from binge drinking to addiction. In addition, we emphasise adolescence as a sensitive period for the confluence of alcohol harmful effects and emotional dysregulation in the developing gut-brain axis.
- ItemThe gut microbiota alone and in combination with a social stimulus regulates cocaine reward in the mouse(Elsevier B.V., 2022-11-02) García-Cabrerizo, Rubén; Barros-Santos, Thaísa; Campos, David; Cryan, John F.; Horizon 2020; Science Foundation IrelandThe gut microbiota is a key factor in the maintenance of physiological homeostasis and immunity. Correlational studies have demonstrated that alterations in microbiota composition have been associated with addiction. Moreover, animal studies have confirmed a link between reward and social processes, which may be shaped by the gut microbiota thus influencing neurodevelopment and the programming of social behaviors across diverse animal species. However, whether there is an interaction between the microbiota and social reward processes in the context of drug reward remains unclear. To this end, we explored the influence of gut microbiota in regulating behaviourally conditioned responses to different rewards (cocaine and social interactions). Depletion of the intestinal microbiota resulted in differential reward responses to both drug and social stimuli with an attenuation of the former and enhancement of the latter independent of concomitant immune changes. Moreover, the combination of depleting the gut microbiota in the presence of a positive social stimulus attenuates cocaine reward. Together these data suggest that the two-pronged approach of targeting the microbiota and enhancing social behaviour could constitute a valuable component in reducing harm in drug use by altering the salient effects of cocaine.
- ItemThe microbiome-gut-brain axis regulates social cognition and craving in young binge drinkers(Elsevier B.V., 2023-03-10) Carbia, Carina; Bastiaanssen, Thomaz F. S.; Iannone, Luigi Francesco; García-Cabrerizo, Rubén; Boscaini, Serena; Berding, Kirsten; Strain, Conall R.; Clarke, Gerard; Stanton, Catherine; Dinan, Timothy G.; Noonan, John F.; Horizon 2020; Science Foundation IrelandBackground: Binge drinking is the consumption of an excessive amount of alcohol in a short period of time. This pattern of consumption is highly prevalent during the crucial developmental period of adolescence. Recently, the severity of alcohol use disorders (AUDs) has been linked with microbiome alterations suggesting a role for the gut microbiome in its development. Furthermore, a strong link has emerged too between microbiome composition and socio-emotional functioning across different disorders including AUD. The aim of this study was to investigate the potential link (and its predictive value) between alcohol-related altered microbial profile, social cognition, impulsivity and craving. Methods: Young people (N = 71) aged 18–25 reported their alcohol use and underwent a neuropsychological evaluation. Craving was measured at baseline and three months later. Diet was controlled for. Blood, saliva and hair samples were taken for inflammatory, kynurenine and cortisol analysis. Stool samples were provided for shotgun metagenomic sequencing and short-chain fatty acids (SCFAs) were measured. Findings: Binge drinking was associated with distinct microbiome alterations and emotional recognition difficulties. Associations were found for several microbiome species with emotional processing and impulsivity. Craving showed a strong link with alterations in microbiome composition and neuroactive potential over time. Interpretation: In conclusion, this research demonstrates alterations in the gut microbiome of young binge drinkers (BDs) and identifies early biomarkers of craving. Associations between emotional processing and microbiome composition further support the growing literature on the gut microbiome as a regulator of social cognition. These findings are of relevance for new gut-derived interventions directed at improving early alcohol-related alterations during the vulnerability period of adolescence.