Glioma-induced inhibition of caspase-3 in microglia promotes a tumor-supportive phenotype.

Glioma cells recruit and exploit microglia (the resident immune cells of the brain) for their proliferation and invasion ability. The underlying molecular mechanism used by glioma cells to transform microglia into a tumor-supporting phenotype has remained elusive. We found that glioma-induced microglia conversion was coupled to a reduction in the basal activity of microglial caspase-3 and increased S-nitrosylation of mitochondria-associated caspase-3 through inhibition of thioredoxin-2 activity, and that inhibition of caspase-3 regulated microglial tumor-supporting function. Furthermore, we identified the activity of nitric oxide synthase 2 (NOS2, also known as iNOS) originating from the glioma cells as a driving stimulus in the control of microglial caspase-3 activity. Repression of glioma NOS2 expression in vivo led to a reduction in both microglia recruitment and tumor expansion, whereas depletion of microglial caspase-3 gene promoted tumor growth. Our results provide evidence that inhibition of the denitrosylation of S-nitrosylated procaspase-3 mediated by the redox protein Trx2 is a part of the microglial pro-tumoral activation pathway initiated by glioma cancer cells.

Microglia depletion and repopulation do not alter the effects of cranial irradiation on hippocampal neurogenesis.

Cranial radiotherapy can cause lifelong cognitive complications in childhood brain tumor survivors, and reduced hippocampal neurogenesis is hypothesized to contribute to this. Following irradiation (IR), microglia clear dead neural progenitors and give rise to a neuroinflammatory microenvironment, which promotes a switch in surviving progenitors from neuronal to glial differentiation. Recently, depletion and repopulation of microglia were shown to promote neurogenesis and ameliorate cognitive deficits in various brain injury models. In this study, we utilized the Cx3cr1CreERt2-YFP/+Rosa26DTA/+ transgenic mouse model to deplete microglia in the juvenile mouse brain before subjecting them to whole-brain IR and investigated the short- and long-term effects on hippocampal neurogenesis. Within the initial 24 h after IR, the absence of microglia led to an accumulation of dead cells in the subgranular zone, and 50-fold higher levels of the chemokine C-C motif ligand 2 (CCL2) in sham brains and 7-fold higher levels after IR. The absence of microglia, and the subsequent repopulation within 10 days, did neither affect the loss of proliferating or doublecortin-positive cells, nor the reduced growth of the granule cell layer. Our results argue against a role for a pro-inflammatory microenvironment in the dysregulation of hippocampal neurogenesis and suggest that the observed reduction of neurogenesis was solely due to IR.

Dynamic microglia alterations associate with hippocampal network impairments: A turning point in amyloid pathology progression.

Alzheimer's disease is a progressive neurological disorder causing memory loss and cognitive decline. The underlying causes of cognitive deterioration and neurodegeneration remain unclear, leading to a lack of effective strategies to prevent dementia. Recent evidence highlights the role of neuroinflammation, particularly involving microglia, in Alzheimer's disease onset and progression. Characterizing the initial phase of Alzheimer's disease can lead to the discovery of new biomarkers and therapeutic targets, facilitating timely interventions for effective treatments. We used the AppNL-G-F knock-in mouse model, which resembles the amyloid pathology and neuroinflammatory characteristics of Alzheimer's disease, to investigate the transition from a pre-plaque to an early plaque stage with a combined functional and molecular approach. Our experiments show a progressive decrease in the power of cognition-relevant hippocampal gamma oscillations during the early stage of amyloid pathology, together with a modification of fast-spiking interneuron intrinsic properties and postsynaptic input. Consistently, transcriptomic analyses revealed that these effects are accompanied by changes in synaptic function-associated pathways. Concurrently, homeostasis- and inflammatory-related microglia signature genes were downregulated. Moreover, we found a decrease in Iba1-positive microglia in the hippocampus that correlates with plaque aggregation and neuronal dysfunction. Collectively, these findings support the hypothesis that microglia play a protective role during the early stages of amyloid pathology by preventing plaque aggregation, supporting neuronal homeostasis, and overall preserving the oscillatory network's functionality. These results suggest that the early alteration of microglia dynamics could be a pivotal event in the progression of Alzheimer's disease, potentially triggering plaque deposition, impairment of fast-spiking interneurons, and the breakdown of the oscillatory circuitry in the hippocampus.

A new subtype of diffuse midline glioma, H3 K27 and BRAF/FGFR1 co-altered: a clinico-radiological and histomolecular characterisation.

Diffuse midline gliomas (DMG) H3 K27-altered are incurable grade 4 gliomas and represent a major challenge in neuro-oncology. This tumour type is now classified in four subtypes by the 2021 edition of the WHO Classification of the Central Nervous System (CNS) tumours. However, the H3.3-K27M subgroup still appears clinically and molecularly heterogeneous. Recent publications reported that rare patients presenting a co-occurrence of H3.3K27M with BRAF or FGFR1 alterations tended to have a better prognosis. To better study the role of these co-driver alterations, we assembled a large paediatric and adult cohort of 29 tumours H3K27-altered with co-occurring activating mutation in BRAF or FGFR1 as well as 31 previous cases from the literature. We performed a comprehensive histological, radiological, genomic, transcriptomic and DNA methylation analysis. Interestingly, unsupervised t-distributed Stochastic Neighbour Embedding (tSNE) analysis of DNA methylation profiles regrouped BRAFV600E and all but one FGFR1MUT DMG in a unique methylation cluster, distinct from the other DMG subgroups and also from ganglioglioma (GG) or high-grade astrocytoma with piloid features (HGAP). This new DMG subtype harbours atypical radiological and histopathological profiles with calcification and/or a solid tumour component both for BRAFV600E and FGFR1MUT cases. The analyses of a H3.3-K27M BRAFV600E tumour at diagnosis and corresponding in vitro cellular model showed that mutation in H3-3A was the first event in the oncogenesis. Contrary to other DMG, these tumours occur more frequently in the thalamus (70% for BRAFV600E and 58% for FGFR1MUT) and patients have a longer overall survival with a median above three years. In conclusion, DMG, H3 K27 and BRAF/FGFR1 co-altered represent a new subtype of DMG with distinct genotype/phenotype characteristics, which deserve further attention with respect to trial interpretation and patient management.

Moral distress and ethical climate in pediatric oncology care impact healthcare professionals' intentions to leave.

OBJECTIVE: To assess perceptions of ethical climate, experiences of moral distress, and intentions to leave among healthcare professionals in Nordic pediatric oncology care. METHODS: A cross-sectional survey with registered nurses, physicians, and nursing assistants at 20 Nordic pediatric cancer centers. Data were collected by using translated versions of the Swedish Hospital Ethical Climate Survey-Shortened and the Swedish Moral Distress Scale-Revised. Descriptive analyses and non-parametric tests were used to describe, summarize, and compare data. RESULTS: According to 543 healthcare professionals (response rate 58%), the ethical climate in Nordic pediatric oncology care was positive. Inadequate staffing levels, poor continuity and lack of time were the most common causes of moral distress. Registered nurses experienced significantly higher levels of moral distress compared to physicians and nursing assistants. About 6% of the respondents considered leaving due to moral distress. Typically, they assessed the ethical climate as less positive and reported higher levels of moral distress than those who had no intention to leave. CONCLUSIONS: Organizational actions that ensure safe staffing levels and improve the continuity of care are needed to prevent moral distress and high staff turnover.

Interaction between AIF and CHCHD4 Regulates Respiratory Chain Biogenesis.

Apoptosis-inducing factor (AIF) is a mitochondrial flavoprotein that, beyond its apoptotic function, is required for the normal expression of major respiratory chain complexes. Here we identified an AIF-interacting protein, CHCHD4, which is the central component of a redox-sensitive mitochondrial intermembrane space import machinery. Depletion or hypomorphic mutation of AIF caused a downregulation of CHCHD4 protein by diminishing its mitochondrial import. CHCHD4 depletion sufficed to induce a respiratory defect that mimicked that observed in AIF-deficient cells. CHCHD4 levels could be restored in AIF-deficient cells by enforcing its AIF-independent mitochondrial localization. This modified CHCHD4 protein reestablished respiratory function in AIF-deficient cells and enabled AIF-deficient embryoid bodies to undergo cavitation, a process of programmed cell death required for embryonic morphogenesis. These findings explain how AIF contributes to the biogenesis of respiratory chain complexes, and they establish an unexpected link between the vital function of AIF and the propensity of cells to undergo apoptosis.

An overlooked subset of Cx3cr1wt/wt microglia in the Cx3cr1CreER-Eyfp/wt mouse has a repopulation advantage over Cx3cr1CreER-Eyfp/wt microglia following microglial depletion.

BACKGROUND: Fluorescent reporter labeling and promoter-driven Cre-recombinant technologies have facilitated cellular investigations of physiological and pathological processes, including the widespread use of the Cx3cr1CreER-Eyfp/wt mouse strain for studies of microglia. METHODS: Immunohistochemistry, Flow Cytometry, RNA sequencing and whole-genome sequencing were used to identify the subpopulation of microglia in Cx3cr1CreER-Eyfp/wt mouse brains. Genetically mediated microglia depletion using Cx3cr1CreER-Eyfp/wtRosa26DTA/wt mice and CSF1 receptor inhibitor PLX3397 were used to deplete microglia. Primary microglia proliferation and migration assay were used for in vitro studies. RESULTS: We unexpectedly identified a subpopulation of microglia devoid of genetic modification, exhibiting higher Cx3cr1 and CX3CR1 expression than Cx3cr1CreER-Eyfp/wtCre+Eyfp+ microglia in Cx3cr1CreER-Eyfp/wt mouse brains, thus termed Cx3cr1highCre-Eyfp- microglia. This subpopulation constituted less than 1% of all microglia under homeostatic conditions, but after Cre-driven DTA-mediated microglial depletion, Cx3cr1highCre-Eyfp- microglia escaped depletion and proliferated extensively, eventually occupying one-third of the total microglial pool. We further demonstrated that the Cx3cr1highCre-Eyfp- microglia had lost their genetic heterozygosity and become homozygous for wild-type Cx3cr1. Therefore, Cx3cr1highCre-Eyfp- microglia are Cx3cr1wt/wtCre-Eyfp-. Finally, we demonstrated that CX3CL1-CX3CR1 signaling regulates microglial repopulation both in vivo and in vitro. CONCLUSIONS: Our results raise a cautionary note regarding the use of Cx3cr1CreER-Eyfp/wt mouse strains, particularly when interpreting the results of fate mapping, and microglial depletion and repopulation studies.

Lithium treatment reverses irradiation-induced changes in rodent neural progenitors and rescues cognition.

Cranial radiotherapy in children has detrimental effects on cognition, mood, and social competence in young cancer survivors. Treatments harnessing hippocampal neurogenesis are currently of great relevance in this context. Lithium, a well-known mood stabilizer, has both neuroprotective, pro-neurogenic as well as antitumor effects, and in the current study we introduced lithium treatment 4 weeks after irradiation. Female mice received a single 4 Gy whole-brain radiation dose on postnatal day (PND) 21 and were randomized to 0.24% Li2CO3 chow or normal chow from PND 49 to 77. Hippocampal neurogenesis was assessed on PND 77, 91, and 105. We found that lithium treatment had a pro-proliferative effect on neural progenitors, but neuronal integration occurred only after it was discontinued. Also, the treatment ameliorated deficits in spatial learning and memory retention observed in irradiated mice. Gene expression profiling and DNA methylation analysis identified two novel factors related to the observed effects, Tppp, associated with microtubule stabilization, and GAD2/65, associated with neuronal signaling. Our results show that lithium treatment reverses irradiation-induced loss of hippocampal neurogenesis and cognitive impairment even when introduced long after the injury. We propose that lithium treatment should be intermittent in order to first make neural progenitors proliferate and then, upon discontinuation, allow them to differentiate. Our findings suggest that pharmacological treatment of cognitive so-called late effects in childhood cancer survivors is possible.

Uncovering sex differences of rodent microglia.

There are inherent structural and functional differences in the central nervous systems (CNS) of females and males. It has been gradually established that these sex-specific differences are due to a spectrum of genetic, epigenetic, and hormonal factors which actively contribute to the differential incidences, disease courses, and even outcomes of CNS diseases between sexes. Microglia, as principle resident macrophages in the CNS, play a crucial role in both CNS physiology and pathology. However, sex differences of microglia have been relatively unexplored until recently. Emerging data has convincingly demonstrated the existence of sex-dependent structural and functional differences of rodent microglia, consequently changing our current understanding of these versatile cells. In this review, we attempt to comprehensively outline the current advances revealing microglial sex differences in rodent and their potential implications for specific CNS diseases with a stark sex difference. A detailed understanding of molecular processes underlying microglial sex differences is of major importance in design of translational sex- and microglia-specific therapeutic approaches.

Autophagy in acute brain injury.

Autophagy is an evolutionarily ancient mechanism that ensures the lysosomal degradation of old, supernumerary or ectopic cytoplasmic entities. Most eukaryotic cells, including neurons, rely on proficient autophagic responses for the maintenance of homeostasis in response to stress. Accordingly, autophagy mediates neuroprotective effects following some forms of acute brain damage, including methamphetamine intoxication, spinal cord injury and subarachnoid haemorrhage. In some other circumstances, however, the autophagic machinery precipitates a peculiar form of cell death (known as autosis) that contributes to the aetiology of other types of acute brain damage, such as neonatal asphyxia. Here, we dissect the context-specific impact of autophagy on non-infectious acute brain injury, emphasizing the possible therapeutic application of pharmacological activators and inhibitors of this catabolic process for neuroprotection.

Absence of microglia or presence of peripherally-derived macrophages does not affect tau pathology in young or old hTau mice.

Microglia are implicated in the pathophysiology of several neurodegenerative disorders, including Alzheimer's disease. While the role of microglia and peripheral macrophages in regulating amyloid beta pathology has been well characterized, the impact of these distinct cell subsets on tau pathology remains poorly understood. We and others have recently demonstrated that monocytes can engraft the brain and give rise to long-lived parenchymal macrophages, even under nonpathological conditions. We undertook the current study to investigate the regulation of tau pathology by microglia and peripheral macrophages using hTau transgenic mice, which do not exhibit microglial activation/pathology or macrophage engraftment. To assess the direct impact of microglia on tau pathology we developed a protocol for long-term microglial depletion in Cx3cr1CreER R26DTA mice and crossed them with hTau mice. We then depleted microglia up to 3 months in both young and old mice, but no net change in forebrain soluble oligomeric tau or total or phosphorylated levels of aggregated tau was recorded. To investigate the consequence of peripherally-derived parenchymal macrophages on tau aggregation we partially repopulated the hTau microglial pool with peripheral macrophages, but this also did not affect levels of tau oligomers or insoluble aggregates. Our study questions the direct involvement of microglia or peripheral macrophages in the development of tau pathology in the hTau model.

Autophagy in neurodegeneration: New insights underpinning therapy for neurological diseases.

In autophagy long-lived proteins, protein aggregates or damaged organelles are engulfed by vesicles called autophagosomes prior to lysosomal degradation. Autophagy dysfunction is a hallmark of several neurodegenerative diseases in which misfolded proteins or dysfunctional mitochondria accumulate. Excessive autophagy can also exacerbate brain injury under certain conditions. In this review, we provide specific examples to illustrate the critical role played by autophagy in pathological conditions affecting the brain and discuss potential therapeutic implications. We show how a singular type of autophagy-dependent cell death termed autosis has attracted attention as a promising target for improving outcomes in perinatal asphyxia and hypoxic-ischaemic injury to the immature brain. We provide evidence that autophagy inhibition may be protective against radiotherapy-induced damage to the young brain. We describe a specialized form of macroautophagy of therapeutic relevance for motoneuron and neuromuscular diseases, known as chaperone-assisted selective autophagy, in which heat shock protein B8 is used to deliver aberrant proteins to autophagosomes. We summarize studies pinpointing mitophagy mediated by the serine/threonine kinase PINK1 and the ubiquitin-protein ligase Parkin as a mechanism potentially relevant to Parkinson's disease, despite debate over the physiological conditions in which it is activated in organisms. Finally, with the example of the autophagy-inducing agent rilmenidine and its discrepant effects in cell culture and mouse models of motor neuron disorders, we illustrate the importance of considering aspects such a disease stage and aggressiveness, type of insult and load of damaged or toxic cellular components, when choosing the appropriate drug, timepoint and duration of treatment.

Aggravated brain injury after neonatal hypoxic ischemia in microglia-depleted mice.

BACKGROUND: Neuroinflammation plays an important role in neonatal hypoxic-ischemic encephalopathy (HIE). Although microglia are largely responsible for injury-induced inflammatory response, they play beneficial roles in both normal and disease states. However, the effects of microglial depletion on neonatal HIE remain unclear. METHODS: Tamoxifen was administered to Cx3cr1CreER/+Rosa26DTA/+ (microglia-depleted model) and Cx3cr1CreER/+Rosa26DTA/- (control) mice at P8 and P9 to assess the effect of microglial depletion. The density of microglia was quantified using Iba-1 staining. Moreover, the proportion of resident microglia after the HI insult was analyzed using flow cytometric analysis. At P10, the HI insult was conducted using the Rice-Vannucci procedure at P10. The infarct size and apoptotic cells were analyzed at P13. Cytokine analyses were performed using quantitative polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA) at P13. RESULTS: At P10, tamoxifen administration induced > 99% microglial depletion in DTA+ mice. Following HI insult, there was persisted microglial depletion over 97% at P13. Compared to male DTA- mice, male DTA+ mice exhibited significantly larger infarct volumes; however, there were no significant differences among females. Moreover, compared to male DTA- mice, male DTA+ mice had a significantly higher density of TUNEL+ cells in the caudoputamen, cerebral cortex, and thalamus. Moreover, compared to female DTA- mice, female DTA+ mice showed a significantly greater number of TUNEL+ cells in the hippocampus and thalamus. Compared to DTA- mice, ELISA revealed significantly lower IL-10 and TGF-ß levels in both male and female DTA+ mice under both normal conditions and after HI (more pronounced). CONCLUSION: We established a microglial depletion model that aggravated neuronal damage and apoptosis after the HI insult, which was predominantly observed in males.

A nationwide, population-based study of school grades, delayed graduation, and qualification for school years 10-12, in children with brain tumors in Sweden.

BACKGROUND: As many as 95.7% of children diagnosed with a brain tumor will experience persistent late effects as adults. These include difficulties with general executive functions, lower IQ, and mental fatigue, which may negatively affect school performance. METHODS: Through the Swedish Childhood Cancer Registry, we identified 475 children born between 1988 and 1996, diagnosed with a brain tumor before their 15th birthday. School grades in "Swedish," "mathematics," and "English," if their graduation was delayed, and qualification for school years 10-12 were compared with 2197 matched controls. Furthermore, we checked for interaction effects between sex and age at diagnosis, and possible effects of tumor grade (high or low) as well as parents' education. RESULTS: Children treated for a brain tumor performed worse in the subjects compared to controls and also had delayed graduation to a greater extent. Fewer children treated for a brain tumor than controls qualified for school years 10-12. Children treated at a young age, especially females, and children whose parents have low education seem to be at particular risk. Unexpectedly, there were no differences in outcomes between survivors with high- and low-grade tumors. CONCLUSIONS: It is important that schools provide regular pedagogical assessment and individualized support to meet the different needs of children treated for a brain tumor. Children treated for low-grade tumors do not perform better than children treated for high-grade tumors, despite the lighter treatment, and hence require the same attention and support.

Underestimated Peripheral Effects Following Pharmacological and Conditional Genetic Microglial Depletion.

Microglia, predominant parenchymal resident macrophages in the central nervous system (CNS), are crucial players in neurodevelopment and CNS homeostasis. In disease conditions, pro-inflammatory microglia predominate over their regulatory counterparts, and are thus a potential immunotherapeutic target. It has been well documented that microglia can be effectively depleted using both conditional genetic Cx3cr1Cre-diphtheria toxin receptor (DTR)/diphtheria toxin subunit A (DTA) animal models and pharmacological colony-stimulating factor 1 receptor (CSF1R) inhibitors. Recent advances using these approaches have expanded our knowledge of the multitude of tasks conducted by microglia in both homeostasis and diseases. Importantly, experimental microglial depletion has been proven to exert neuroprotective effects in an increasing number of disease models, mostly explained by reduced neuroinflammation. However, the comprehensive effects of additional targets such as circulating monocytes and peripheral tissue macrophages during microglial depletion periods have not been investigated widely, and for those studies addressing the issue the conclusions are mixed. In this study, we demonstrate that experimental microglial depletion using both Cx3cr1CreER/+Rosa26DTA/+ mice and different doses of CSF1R inhibitor PLX3397 exert crucial influences on circulating monocytes and peripheral tissue macrophages. Our results suggest that effects on peripheral immunity should be considered both in interpretation of microglial depletion studies, and especially in the potential translation of microglial depletion and replacement therapies.

Sex-Specific Effects of Microglia-Like Cell Engraftment during Experimental Autoimmune Encephalomyelitis.

Multiple sclerosis (MS) is a chronic neuroinflammatory disorder of the central nervous system (CNS) that usually presents in young adults and predominantly in females. Microglia, a major resident immune cell in the CNS, are critical players in both CNS homeostasis and disease. We have previously demonstrated that microglia can be efficiently depleted by the administration of tamoxifen in Cx3cr1CreER/+Rosa26DTA/+ mice, with ensuing repopulation deriving from both the proliferation of residual CNS resident microglia and the engraftment of peripheral monocyte-derived microglia-like cells. In this study, tamoxifen was administered to Cx3cr1CreER/+Rosa26DTA/+ and Cx3cr1CreER/+ female and male mice. Experimental autoimmune encephalomyelitis (EAE), a widely used animal model of MS, was induced by active immunization with myelin oligodendrocyte glycoprotein (MOG) one month after tamoxifen injections in Cx3cr1CreER/+Rosa26DTA/+ mice and Cx3cr1CreER/+ mice, a time point when the CNS niche was colonized by microglia derived from both CNS microglia and peripherally-derived macrophages. We demonstrate that engraftment of microglia-like cells following microglial depletion exacerbated EAE in Cx3cr1CreER/+Rosa26DTA/+ female mice as assessed by clinical symptoms and the expression of CNS inflammatory factors, but these findings were not evident in male mice. Higher major histocompatibility complex class II expression and cytokine production in the female CNS contributed to the sex-dependent EAE severity in mice following engraftment of microglia-like cells. An underestimated yet marked sex-dependent microglial activation pattern may exist in the injured CNS during EAE.

Language barriers and the use of professional interpreters: a national multisite cross-sectional survey in pediatric oncology care.

Background: Healthcare personnel are responsible for providing patient-centered care regardless of their patients' language skills, but language barriers is identified as the main hindrances providing effective, equitable and safe care to patients with limited proficiency in a country's majority language. This study is a national multisite cross-sectional survey aiming to investigate communication over language barriers in pediatric oncology care. Material and Methods: A survey using the Communication over Language Barriers questionnaire (CoLB-q) distributed to medical doctors, registered nurses and nursing assistants at six pediatric oncology centers in Sweden (response rate 90%) using descriptive statistical analyses. Results: Professional interpreters on site were the most common solution when using an interpreter, although relatives or even children were used. The use of professional interpreters on site differed among the professions and in different clinical situations, such as medical encounter, education or procedure preparation. All professions reported that the use of professional interpreters greatly increased care relationships, patient safety and patient involvement in care. Conclusions: Healthcare personnel seem to believe that professional interpreters are crucial when caring for patients and family members who do not speak the majority language, but there is an obvious discrepancy between this belief and their use of professional interpreters.

Moral distress in paediatric oncology: Contributing factors and group differences.

BACKGROUND: Providing oncological care to children is demanding and ethical issues concerning what is best for the child can contribute to moral distress. OBJECTIVES: To explore healthcare professionals' experiences of situations that generate moral distress in Swedish paediatric oncology. RESEARCH DESIGN: In this national study, data collection was conducted using the Swedish Moral Distress Scale-Revised. The data analysis included descriptive statistics and non-parametric analysis of differences between groups. PARTICIPANTS AND RESEARCH CONTEXT: Healthcare professionals at all paediatric oncology centres in Sweden were invited to participate. A total of 278 healthcare professionals participated. The response rate was 89%. ETHICAL CONSIDERATIONS: In its advisory statement, the Regional Ethical Review Board decided that the study was of such a nature that the legislation concerning ethical reviews was not applicable. All participants received written information about the aim of the study and confidentiality. Participants demonstrated their consent by returning the survey. FINDINGS: The two situations with the highest moral distress scores concerned lack of competence and continuity of personnel. All professional groups reported high levels of disturbance. Nurses rated significantly higher frequencies and higher total Moral Distress Scale scores compared to medical doctors and nursing assistants. DISCUSSION: Lack of competence and continuity, as the two most morally distressing situations, confirms the findings of studies from other countries, where inadequate staffing was reported as being among the top five morally distressing situations. The levels of total Moral Distress Scale scores were more similar to those reported in intensive care units than in other paediatric care settings. CONCLUSION: The two most morally distressing situations, lack of competence and continuity, are both organisational in nature. Thus, clinical ethics support services need to be combined with organisational improvements in order to reduce moral distress, thereby maintaining job satisfaction, preventing a high turnover of staff and ensuring the quality of care.

Ethics case reflection sessions: Enablers and barriers.

BACKGROUND: In previous research on ethics case reflection (ECR) sessions about specific cases, healthcare professionals in childhood cancer care were clarifying their perspectives on the ethical issue to resolve their main concern of consolidating care. When perspectives were clarified, consequences in the team included 'increased understanding', 'group strengthening' and 'decision grounding'. Additional analysis of the data was needed on conditions that could contribute to the quality of ECR sessions. OBJECTIVE: The aim of this study was to explore conditions for clarifying perspectives during ECR sessions. RESEARCH DESIGN: Data were collected from observations and interviews and the results emerged from an inductive analysis using grounded theory. Participants and research context: Six observations during ECR sessions and 10 interviews were performed with healthcare professionals working in childhood cancer care and advanced paediatric homecare. Ethical considerations: The study was approved by a regional ethical review board. Participants were informed about their voluntary involvement and that they could withdraw their participation without explaining why. FINDINGS: Two categories emerged: organizational enablers and barriers and team-related enablers and barriers. Organizational enablers and barriers included the following sub-categories: the timing of the ECR session, the structure during the ECR session and the climate during the ECR session. Sub-categories to team-related enablers and barriers were identified as space for inter-professional perspectives, varying levels of ethical skills and space for the patient's and the family's perspectives. DISCUSSION: Space for inter-professional perspectives included the dominance of a particular perspective that can result from hierarchical positions. The medical perspective is relevant for understanding the child's situation but should not dominate the ethical reflection. CONCLUSION: Conditions for ECR sessions have been explored and the new knowledge can be used when training facilitators as well as for those who organize/implement ECR sessions. Awareness of space for different perspectives, including the possible medical advantage over the nursing perspective, could reduce the somewhat unilateral attention and contribute to an inter-professionally shared reflection.

A novel mouse model of radiation-induced cancer survivorship diseases of the gut.

A deeper understanding of the radiation-induced pathophysiological processes that develop in the gut is imperative to prevent, alleviate, or eliminate cancer survivorship diseases after radiotherapy to the pelvic area. Most rodent models of high-dose gastrointestinal radiation injury are limited by high mortality. We therefore established a model that allows for the delivering of radiation in fractions at high doses while maintaining long-term survival. Adult male C57/BL6 mice were exposed to small-field irradiation, restricted to 1.5 cm of the colorectum using a linear accelerator. Each mouse received 6 or 8 Gy, two times daily in 12-h intervals in two, three, or four fractions. Acute cell death was examined at 4.5 h postirradiation and histological changes at 6 wk postirradiation. Another group was given four fractions of 8 Gy and followed over time for development of visible symptoms. Irradiation caused immediate cell death, mainly limited to the colorectum. At 6 wk postirradiation, several crypts displayed signs of radiation-induced degeneration. The degenerating crypts were seen alongside crypts that appeared perfectly healthy. Crypt survival was reduced after the fourth fraction regardless of dose, whereas the number of macrophages increased. Angiogenesis was induced, likely as a compensatory mechanism for hypoxia. Four months postirradiation, mice began to show radiation-induced symptoms, and histological examination revealed an extensive crypt loss and fibrosis. Our model is uniquely suitable for studying the long-term trajectory and underlying mechanisms of radiation-induced gastrointestinal injury.NEW & NOTEWORTHY A novel mouse model for studying the long-term trajectory of radiation-induced gut injury. The method allows for the use of high doses and multiple fractions, with minor impact on animal health for at least 3 mo. Crypt loss and a slow progression of fibrosis is observed. Crypt degeneration is a process restricted to isolated crypts. Crypt degeneration is presented as a convenient proxy endpoint for long-term radiation-induced gut injury.