Single-cell sequencing to investigate metabolic stress in the pathology of organ injury following cardiac surgery

Organ injury is a major cause of health complications and in-hospital mortality following cardiac surgery. Mechanisms of biological ageing promote the development of long-term (chronic) conditions which can increase patient susceptibility to these adverse outcomes. To characterise these underlying mechanisms at single-cell resolution, this project sought to profile transcriptomic and chromatin accessibility profiles of atrial cardiac cells from multimorbidity and non-multimorbidity patients recruited to the Ob-Card trial (NCT02908009) using single-cell RNA sequencing (scRNA-seq) and single-nuclei assay for transposase-accessible chromatin sequencing (snATAC-seq). Optimised methods for single-nuclei RNA sequencing (snRNA-seq) provided a better representation of cardiomyocytes and data reproducibility than methods for scRNA-seq using mouse and human heart tissue. Peripheral blood leucocytes from patients and healthy volunteers were used to optimise methods for scRNA-seq and chromatin immunoprecipitation (ChIP) quantitative polymerase chain reaction (qPCR). Methods for snRNA-seq were used for atrial tissue from high (n=9) and low (n=12) multimorbidity patients. Cardiomyocytes (47.2%), fibroblasts (10.2%), various subpopulations of endothelial cells, myeloid cells, lymphoid cells, and other cardiac cell types were identified. Differential gene expression and pathway enrichment analysis found a significant upregulation of translational, ribosomal, protein homeostatic, and apoptotic pathways in cardiac cell types of high multimorbidity patients, with a significant downregulation of cardiac development and contraction processes. Other cell type-specific biological ageing mechanisms, including epigenetic dysregulation, DNA damage/oxidative stress, and immune/inflammatory responses were identified. This was supported by transcription factor (TF) regulatory network and cell-type interaction analyses between immune cells and non-immune cells. snATAC-seq of snap-frozen patient atrial tissue could not be used to relate findings to changes in chromatin structure. These results provide an exploratory approach in characterising biological ageing mechanisms in cardiac cell types of high multimorbidity patients at single-cell resolution, which can help to develop effective risk stratification and therapeutic strategies to avert organ injury and poor outcomes following cardiac surgery.</p

Images of Research 2020

Images Of Research 2020 Winners: Martha Papadopoulou – ‘Melting The Secrets Of Rocks’ - Judges’ Prize Winner and People’s Choice Runner-up Pedro Rodriguez Veiga – ‘Art Meets Radar’ - Judges’ Prize Runners-up Damian Roland – ‘COVID19 And Children: The True Cost Of The Pandemic’ - Katherine May People’s Choice Winner and Leicester Institute of Advanced Studies Interdisciplinary Prize Victoria Szafara - ‘Feeding The Machine’ - Leicester Institute of Advanced Studies Interdisciplinary Prize Images Of Research 2020 submissions: Barry Hawthorne – ‘Transport to death or transport to safety?’ Chiara Marabelli – ‘The ‘aura’ of the original?’ Christian Harrison – ‘The Beauty in the Small Things’ Denise Corsel – ‘With Fish Under their Feet, How Could You Ever Go Hungry?’ Emily Richardson – ‘Beautiful, But Deadly.’ Freya Tyrer – ‘Let’s Talk about Health!’ Helen Elliott-Mainwaring – ‘Kitchen Table Research in a Pandemic’ Jack O'Doherty – ‘Aegis’ Kellie Lucken – ‘Cancer cells promote cell division errors’ Laura Albertini – ‘Here we used to cross the river’ Michael J Curtis – ‘An ancient mariner’s tale’ Paige Emerick – ‘Royal Road’ Shirley Yang – ‘Scandalous man missing in the news ‘ Sohaib Rufai – ‘Window of the Soul’ Sophia Sheikh & Kristina Tomkova – ‘At the CELLestial level’ Tia Ndu – ‘The height of gentrification?’ Tom Matheson – ‘Abandoned’ Vinay Patel – ‘Microstructure from a Steel Alloy Wheel from a Earth Moving Vehicle’</p

DataSheet_1_Post-traumatic stress and future substance use outcomes: leveraging antecedent factors to stratify risk.docx

BackgroundPost-traumatic stress disorder (PTSD) and substance use (tobacco, alcohol, and cannabis) are highly comorbid. Many factors affect this relationship, including sociodemographic and psychosocial characteristics, other prior traumas, and physical health. However, few prior studies have investigated this prospectively, examining new substance use and the extent to which a wide range of factors may modify the relationship to PTSD.MethodsThe Advancing Understanding of RecOvery afteR traumA (AURORA) study is a prospective cohort of adults presenting at emergency departments (N = 2,943). Participants self-reported PTSD symptoms and the frequency and quantity of tobacco, alcohol, and cannabis use at six total timepoints. We assessed the associations of PTSD and future substance use, lagged by one timepoint, using the Poisson generalized estimating equations. We also stratified by incident and prevalent substance use and generated causal forests to identify the most important effect modifiers of this relationship out of 128 potential variables.ResultsAt baseline, 37.3% (N = 1,099) of participants reported likely PTSD. PTSD was associated with tobacco frequency (incidence rate ratio (IRR): 1.003, 95% CI: 1.00, 1.01, p = 0.02) and quantity (IRR: 1.01, 95% CI: 1.001, 1.01, p = 0.01), and alcohol frequency (IRR: 1.002, 95% CI: 1.00, 1.004, p = 0.03) and quantity (IRR: 1.003, 95% CI: 1.001, 1.01, p = 0.001), but not with cannabis use. There were slight differences in incident compared to prevalent tobacco frequency and quantity of use; prevalent tobacco frequency and quantity were associated with PTSD symptoms, while incident tobacco frequency and quantity were not. Using causal forests, lifetime worst use of cigarettes, overall self-rated physical health, and prior childhood trauma were major moderators of the relationship between PTSD symptoms and the three substances investigated.ConclusionPTSD symptoms were highly associated with tobacco and alcohol use, while the association with prospective cannabis use is not clear. Findings suggest that understanding the different risk stratification that occurs can aid in tailoring interventions to populations at greatest risk to best mitigate the comorbidity between PTSD symptoms and future substance use outcomes. We demonstrate that this is particularly salient for tobacco use and, to some extent, alcohol use, while cannabis is less likely to be impacted by PTSD symptoms across the strata.</p

Characteristics of study population.

Characteristics of study population.</p

Enrollment, follow-up, and exclusion criteria flow diagram for persons in analysis.

Enrollment, follow-up, and exclusion criteria flow diagram for persons in analysis.</p

Logistic regression model for at-risk opioid use during 3-month follow-up after ed visit for trauma.

Logistic regression model for at-risk opioid use during 3-month follow-up after ed visit for trauma.</p