Respiratory chain signalling is essential for adaptive remodelling following cardiac ischaemia

Abstract Cardiac ischaemia-reperfusion (I/R) injury has been attributed to stress signals arising from an impaired mitochondrial electron transport chain (ETC), which include redox imbalance, metabolic stalling and excessive production of reactive oxygen species (ROS). The alternative oxidase (AOX) is a respiratory enzyme, absent in mammals, that accepts electrons from a reduced quinone pool to reduce oxygen to water, thereby restoring electron flux when impaired and, in the process, blunting ROS production. Hence, AOX represents a natural rescue mechanism from respiratory stress. This study aimed to determine how respiratory restoration through xenotopically expressed AOX affects the re-perfused post-ischaemic mouse heart. As expected, AOX supports ETC function and attenuates the ROS load in post-anoxic heart mitochondria. However, post-ischaemic cardiac remodelling over 3 and 9 weeks was not improved. AOX blunted transcript levels of factors known to be up-regulated upon I/R such as the atrial natriuretic peptide (Anp) whilst expression of pro-fibrotic and pro-apoptotic transcripts were increased. Ex vivo analysis revealed contractile failure at nine but not 3 weeks after ischaemia whilst label-free quantitative proteomics identified an increase in proteins promoting adverse extracellular matrix remodelling. Together, this indicates an essential role for ETC-derived signals during cardiac adaptive remodelling and identified ROS as a possible effector.Peer reviewe

Respiratory chain signalling is essential for adaptive remodelling following cardiac ischaemia

Abstract Cardiac ischaemia-reperfusion (I/R) injury has been attributed to stress signals arising from an impaired mitochondrial electron transport chain (ETC), which include redox imbalance, metabolic stalling and excessive production of reactive oxygen species (ROS). The alternative oxidase (AOX) is a respiratory enzyme, absent in mammals, that accepts electrons from a reduced quinone pool to reduce oxygen to water, thereby restoring electron flux when impaired and, in the process, blunting ROS production. Hence, AOX represents a natural rescue mechanism from respiratory stress. This study aimed to determine how respiratory restoration through xenotopically expressed AOX affects the re-perfused post-ischaemic mouse heart. As expected, AOX supports ETC function and attenuates the ROS load in post-anoxic heart mitochondria. However, post-ischaemic cardiac remodelling over 3 and 9 weeks was not improved. AOX blunted transcript levels of factors known to be up-regulated upon I/R such as the atrial natriuretic peptide (Anp) whilst expression of pro-fibrotic and pro-apoptotic transcripts were increased. Ex vivo analysis revealed contractile failure at nine but not 3 weeks after ischaemia whilst label-free quantitative proteomics identified an increase in proteins promoting adverse extracellular matrix remodelling. Together, this indicates an essential role for ETC-derived signals during cardiac adaptive remodelling and identified ROS as a possible effector.Peer reviewe

Painful skin lesions and squamous cell carcinoma predict overall mortality risk in organ transplant recipients:a cohort study

Item does not contain fulltextBACKGROUND: Organ transplant recipients (OTRs) have a highly increased risk of cutaneous squamous cell carcinomas (SCCs). Sensation of pain in cutaneous tumours is a powerful patient-reported warning signal for invasive SCCs in OTRs. OBJECTIVES: To investigate the impact of painful vs. painless skin lesions and SCC vs. other skin lesions on the overall mortality risk in OTRs. METHODS: We followed 410 OTRs from 10 different centres across Europe and North America between 2008 and 2015. These patients had been enrolled in an earlier study to define clinically meaningful patient-reported warning signals predicting the presence of SCC, and had been included if they had a lesion requiring histological diagnosis. Cumulative incidences of overall mortality were calculated using Kaplan-Meier survival analysis, and risk factors were analysed with Cox proportional hazard analysis. RESULTS: There was an increased overall mortality risk in OTRs who reported painful vs. painless skin lesions, with a hazard ratio (HR) of 1.6 [95% confidence interval (CI) 0.97-2.7], adjusted for age, sex and other relevant factors. There was also an increased overall mortality risk in OTRs diagnosed with SCC compared with other skin lesions, with an adjusted HR of 1.7 (95% CI 1.0-2.8). Mortality due to internal malignancies and systemic infections appeared to prevail in OTRs with SCC. CONCLUSIONS: We suggest that OTRs have an increased overall mortality risk if they develop painful skin lesions or are diagnosed with cutaneous SCC

Spin-flip Raman scattering from donors in diluted magentic semiconductors

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Peripheral nerve atrophy together with higher CSF progranulin indicate axonal damage in ALS

Introduction: We aimed to investigate whether sonographic peripheral cross-sectional nerve area (CSA) and progranulin (PGRN), a neuritic growth factor, are related to each other and whether they interact to predict clinical and paraclinical measures in amyotrophic lateral sclerosis (ALS). Methods: We included 55 ALS patients who had forearm median and ulnar nerve CSA, cerebrospinal fluid (CSF) PGRN, and serum PGRN measures available. CSF PGRN was normalized against the CSF / serum albumin ratio (Q). Using age, sex, height, and weight adjusted general linear models, we examined CSA × CSF PGRN interaction effects on various measures. Results: There was a medium-effect size inverse relationship between CSA and CSF PGRN, but not between CSA and serum PGRN. Lower CSA values together with higher CSF PGRN levels were linked to smaller motor amplitudes. Discussion: In ALS, the constellation of peripheral nerve atrophy together with higher CSF PGRN levels indicates pronounced axonal damage. Muscle Nerve 57: 273–278, 2018