Synthesis of the European ALARA network 20th workshop 'ALARA for interventional radiology and nuclear medicine'.

The European as low as reasonably achievable(ALARA) network regularly organises workshops on topical issues in radiation protection (RP). The topic of the 20th workshop was: 'ALARA for interventional radiology (IR) and nuclear medicine (NM)'. The objective was to examine the challenges faced when applying the optimisation principle (ALARA) in IR and NM and to consider how ALARA could be better implemented for patient and staff exposures. This memorandum provides a synthesis of the workshop sessions, and recommendations coming from the working groups discussion. Parallels are drawn with the recommendations arising from the 13th EAN workshop on 'ALARA and the medical sector (2011)' to consider how the optimisation challenges in IR and NM have evolved over the past decade. Current levels of exposure are presented along with operational practice and the challenges and opportunities for improvement, both in monitoring and practice. Whilst RP challenges remain, the application of ALARA appears more established in IR compared with experiences reported in 2011. The application of ALARA to emerging technologies in the NM setting is in need of further development to ensure that RP is considered at all stages in the development process of new radiopharmaceuticals. Besides the obvious technical and operational aspects, the importance of education and training, human factors and broadly the RP 'culture' were deemed fundamental to the success of the application of ALARA and where further emphasis is needed. All concerned parties, medical physics experts (MPEs), radiation protection experts, clinical staff, manufacturers and regulators have a role to play in the application of ALARA and this is discussed in the memorandum. Many of the recommendations from the 13th EAN workshop remain applicable today and overlap with the recommendations arising from the 20th workshop. This should prompt attention given that the use of IR and the development of novel radiopharmaceuticals for NM is only anticipated to increase with time.

The impact of pneumococcal serotype replacement on the effectiveness of a national immunization program: a population-based active surveillance cohort study in New Zealand.

Background: In Aotearoa New Zealand (NZ) PCV7 was introduced in 2008, then PCV10 in 2011 and PCV13 in 2014. In 2017 PCV10 was re-introduced, replacing PCV13. In the present study, we investigate the resultant rapidly changing invasive pneumococcal disease (IPD) epidemiology. Methods: We compare the IPD incidence rate ratio (IRR) in NZ (2022 versus 2020) with other countries, and describe the IPD epidemiology (including trends in overall IPD and serotype 19A, and antimicrobial resistance) within NZ. Additionally, we performed a genomic-epidemiology investigation identifying the most common 19A sequence types and associated risk factors. Findings: Though IPD incidence rates have increased in the US and Australia (2021-22) after declines in 2020, in NZ the incidence rate is the highest since 2011 with a significantly higher IRR than US (p < 0.01). Incidence rates among children <2 and adults 65 or over in 2022 are the highest since 2009, driven by significant increases of serotype 19A (p = 0.01). Maori and Pacific peoples are experiencing the highest rates since 2009. Further, penicillin resistance among 19A isolates has increased from 39% (2012) to 84% (2021) (p = 0.02). Genomic sequencing identified the more virulent ST-2062 as most common among 19A isolates sequenced, increasing from 5% (2010) to 55% (2022). Interpretation: With very high incidence rates of IPD in NZ, inadequate protection against 19A, increasing resistance, and a more virulent 19A clade, targeted public health campaigns and increased PCV13 availability are needed. Funding: The NZ Ministry of Health funds IPD surveillance and typing in NZ.

Long-term recreational exercise patterns in adolescents and young adults: Trajectory predictors and associations with health, mental-health, and educational outcomes.

Individual and societal factors influencing the formation of long-term recreational exercise habits during the transition from adolescence to young adulthood are not well explored. Using data from the Longitudinal Survey of Australian Youth (LSAY), a population-representative cohort study of Young People followed from age 15 to 25, we aimed to (1) model longitudinal recreational exercise trajectories from age 16 to 24, (2) examine predictors at age 15 of entering these trajectories, and (3) explore the association between the trajectories and health, mental health and educational achievement outcomes measured at the final study wave (age 25). Self-reported recreational exercise frequency data from 9353 LSAY participants were analysed using group-based trajectory modelling. We modelled the evolution of two patterns of recreational exercise behaviour: daily exercise, as per public health guidelines (Model 1); and at least once weekly exercise (Model 2). Model 1 trajectories were guideline-adherent exercisers (17.9% of the sample), never guideline exercisers (27.5%), guideline drop-outs (15.2%) and towards guideline (39.4%); Model 2 trajectories were weekly exercise (69.5% of the sample), decreasing (17.4%), increasing (4.8%), and infrequent (8.3%). For both models, at age 15, trajectory membership was predicted by gender, self-efficacy, time spent participating in sport, time spent watching TV, parental socioeconomic status, and academic literacy. At age 25, people in the guideline-adherent exerciser trajectory (model 1) reported better general health relative to other trajectories, Those in the weekly exerciser trajectory (model 2) had better general health and reduced rates of psychological distress, were happier with life and were more optimistic for the future relative to participants in less than weekly trajectory groups. Exercise-promoting interventions for Young People should specifically address the needs of females, people with low self-efficacy, reluctant exercisers, higher academic achievers, and those experiencing socioeconomic disadvantage.

ICRP workshop on the review and revision of the system of radiological protection: a focus on research priorities-feedback from the international community.

In September 2022, the International Commission on Radiological Protection (ICRP) organised a workshop in Estoril, Portugal, on the 'Review and Revision of the System of Radiological Protection: A Focus on Research Priorities'. The workshop, which was a side event of the European Radiation Protection Week, offered an opportunity to comment on a recent paper published by ICRP on areas of research to support the System of Radiological Protection. Altogether, about 150 individuals participated in the workshop. After the workshop, 16 of the 30 organisations in formal relations with ICRP provided written feedback. All participants and organisations followed ICRP's view that further research in various areas will offer additional support in improving the System in the short, medium, and long term. In general, it was emphasised that any research should be outcome-focused in that it should improve protection of people or the environment. Many research topics mentioned by the participants were in line with those already identified by ICRP in the paper noted above. In addition, further ideas were expressed such as, for example, that lessons learned during the COVID-19 pandemic with regards to the non-radiological social, economic and environment impacts, should be analysed for their usefulness to enhance radiological protection, and that current protection strategies and application of current radiological protection principles may need to be adapted to military scenarios like those observed recently during the military conflict in the Ukraine or the detonation of a nuclear weapon. On a broader perspective, it was discussed how radiation research and radiological protection can contribute towards the Sustainable Development Goals announced by the United Nations in 2015. This paper summarises the views expressed during the workshop and the major take home messages identified by ICRP.

Treatment outcomes and costs of a simplified antiretroviral treatment strategy for hepatitis C among Hepatitis C Virus and Human Immuno deficiency Virus co-infected patients in Ukraine.

Background and Aim: To demonstrate the use of a standard dose of ledipasvir (LDV) and sofosbuvir (SOF), with or without ribavirin, to treat hepatitis C and hepatitis C/HIV co-infection in Ukraine. Methods: Eligible HCV viraemic adults from two clinics in Kyiv were treated with LDV/SOF with or without weight-based ribavirin for 12 weeks. Clinical assessments were performed at screening and at week 24, and as needed; treatment was dispensed every 4 weeks. The primary outcome was sustained virologic response (SVR) 12 weeks after treatment, with analysis by intention to treat. Cost per patient was estimated in USD (2018) over the 24-week period. Results: Of 868 patients included in the study and initiated on therapy, 482 (55.5%) were co-infected with HIV. The common genotypes were 1 (74.1%) and 3 (22%). Overall, SVR was achieved in 831 of the 868 patients (95.7%). SVR in patients with hepatitis C alone and hepatitis C/HIV co-infection was 98.4% and 93.6%, respectively. Adverse events were infrequent and usually mild. Using generic medication, cost per patient was estimated at US$680. Conclusion: A standard dose of LDV and SOF, with ribavirin as per protocol, resulted in good outcomes for patients with both hepatitis C alone and co-infected with hepatitis C/HIV. Program costs in Ukraine were modest using generic medication.

Application of the ALARA principle for radon at work: feedback from the European ALARA network.

The Council Directive 2013/59/Euratom has introduced binding requirements for the management of radon in the workplace in Member States of the European Union. How does it work in practice? In 2021, the European ALARA Network created a working group on ALARA for Radon at Work with the objective of collecting and sharing experiences from the field. A survey was developed to detail each step of the national regulations for the control of radon and to describe case studies showing implementation. This article presents a qualitative analysis of the answers received from seven countries. There are no two similar national regulations and, at each step, different provisions, protocols, techniques etc are applicable or recommended. This diversity contributes to the richness of the results and can inform about interesting and good practices, where 'good' is defined by what is appropriate in the nationally and locally prevailing circumstances. All national regulations follow a graded approach, which is a key component for the implementation of the optimisation (ALARA) principle, yet several potential weak points that may be challenging to ALARA have been identified and are discussed, namely the radon risk assessment, the focus on numerical values, uncertainties in the measurement, how to obtain economically efficient remediation, and the interface with other regulations. Strengthening collaboration between risk prevention and radiation protection actors could help to provide and build expertise on radon management in the workplace, especially when exposure is managed as a planned exposure situation.

Comparative genomics of Bordetella pertussis isolates from New Zealand, a country with an uncommonly high incidence of whooping cough.

Whooping cough, the respiratory disease caused by Bordetella pertussis, has undergone a wide-spread resurgence over the last several decades. Previously, we developed a pipeline to assemble the repetitive B. pertussis genome into closed sequences using hybrid nanopore and Illumina sequencing. Here, this sequencing pipeline was used to conduct a more high-throughput, longitudinal screen of 66 strains isolated between 1982 and 2018 in New Zealand. New Zealand has a higher incidence of whooping cough than many other countries; usually at least twice as many cases per 100000 people as the USA and UK and often even higher, despite similar rates of vaccine uptake. To the best of our knowledge, these strains are the first New Zealand B. pertussis isolates to be sequenced. The analyses here show that, on the whole, genomic trends in New Zealand B. pertussis isolates, such as changing allelic profile in vaccine-related genes and increasing pertactin deficiency, have paralleled those seen elsewhere in the world. At the same time, phylogenetic comparisons of the New Zealand isolates with global isolates suggest that a number of strains are circulating in New Zealand, which cluster separately from other global strains, but which are closely related to each other. The results of this study add to a growing body of knowledge regarding recent changes to the B. pertussis genome, and are the first genetic investigation into B. pertussis isolates from New Zealand.

TNF signaling via TNF receptors does not mediate the effects of short-term exercise on cognition, anxiety and depressive-like behaviors in middle-aged mice.

BACKGROUND: We recently reported that tumor necrosis factor (TNF) signaling via the TNFR1 and TNFR2 receptors mediates the effects of long-term exercise on locomotion, cognition and anxiety, but not depressive-like behavior. We now investigated whether the TNF signaling via its receptors also mediates the effects of short-term exercise on cognition, anxiety and depressive-like behaviors. METHODS: Thirteen-month-old C57BL/6 (WT), TNF-/-, TNFR1-/-, and TNFR2-/- mice were provided with 4 weeks of voluntary wheel running followed by behavioral testing using an established behavioral battery. Each genotype had a respective non-exercise control. RESULTS: There was no interaction between genotype and exercise in any of the tests but the main effect of genotype, and not exercise, were found to be significant in the open field (OF), forced-swim test (FST) and Barnes maze (BM). In the OF, the control and exercise TNFR2-/- mice spent significantly less time in the inner zone than mice in the control and exercise WT and TNF-/- cohorts. In the FST, control and exercise WT mice showed significantly higher immobility time than their control and exercise TNF-/-, TNFR1-/- and TNFR2-/- cohorts. In the BM, the latency to escape over 4 days of training was significantly higher in all KO groups compared to WT, irrespective of exercise. Also, the latency to escape to the original location during the probe trial was higher for control and exercise WT compared to corresponding TNFR1-/- mice. In contrast, the latency to escape to the new location was lower for control and exercise WT compared to control and exercise TNFR1-/- and TNFR2-/- mice. The latency to escape to the new location in exercise groups was longer compared to control within all genotypes. CONCLUSION: While TNF signaling via the TNF receptors mediates cognition, anxiety and depressive-like behaviors independently, it does not mediate the effects of short-term exercise on these behaviors in middle-aged mice.

Psychological training to improve psychosocial function in patients with major depressive disorder: A randomised clinical trial.

Cognitive and emotional remediation training for depression (CERT-D): a randomised controlled trial to improve cognitive, emotional and functional outcomes in depression The aim of the current study was to evaluate an experimental treatment designed to improve psychosocial function in patients with Major Depressive Disorder (MDD) by reinforcing cognitive, emotional, and social-cognitive abilities. Participants (N = 112) with current or lifetime MDD were recruited to participate in a randomised, blinded, controlled trial. Exclusion criteria included diagnosis of a substance abuse disorder, bipolar disorder organic, eating disorders, or illness which affect cognitive function. The treatment involved repeated cognitive training designed to improve cognitive, emotional, and social-cognitive abilities. In training sessions, the principles of cognitive training were applied across cognitive, emotional, and social domains, with participants completing repeated mental exercises. Exercises included critically analysing interpretations of social interactions (e.g., body language), exploring emotional reactions to stimuli, and completing game-like cognitive training tasks. Training sessions placed great emphasis on the application of trained cognitive, emotional, and social cognitive skills to psychosocial outcomes. Outcomes demonstrated significant improvement in psychosocial function, symptom severity, self-reported cognition, and social-cognition. Our findings demonstrate the efficacy of multi-domain cognitive training to improve psychosocial functioning in individuals with MDD. We suggest that the present treatment could be deployed at a lower cost and with minimal training in comparison to established psychological therapies.

Native Human Antibody to Shr Promotes Mice Survival After Intraperitoneal Challenge With Invasive Group A Streptococcus.

BACKGROUND: A vaccine against group A Streptococcus (GAS) has been actively pursued for decades. The surface receptor Shr is vital in GAS heme uptake and provides an effective target for active and passive immunization. Here, we isolated human monoclonal antibodies (mAbs) against Shr and evaluated their efficacy and mechanism. METHODS: We used a single B-lymphocyte screen to discover the mAbs TRL186 and TRL96. Interactions of the mAbs with whole cells, proteins, and peptides were investigated. Growth assays and cultured phagocytes were used to study the mAbs' impact on heme uptake and bacterial killing. Efficacy was tested in prophylactic and therapeutic vaccination using intraperitoneal mAb administration and GAS challenge. RESULTS: Both TRL186 and TRL96 interact with whole GAS cells, recognizing the NTR and NEAT1 domains of Shr, respectively. Both mAbs promoted killing by phagocytes in vitro, but prophylactic administration of only TRL186 increased mice survival. TRL186 improved survival also in a therapeutic mode. TRL186 but not TRL96 also impeded Shr binding to hemoglobin and GAS growth on hemoglobin iron. CONCLUSIONS: Interference with iron acquisition is central for TRL186 efficacy against GAS. This study supports the concept of antibody-based immunotherapy targeting the heme uptake proteins to combat streptococcal infections.

Short-Term Environmental Enrichment is a Stronger Modulator of Brain Glial Cells and Cervical Lymph Node T Cell Subtypes than Exercise or Combined Exercise and Enrichment.

Physical exercise (PE) and environmental enrichment (EE) can modulate immunity. However, the differential effects of short-term PE, EE, and PE + EE on neuroimmune mechanisms during normal aging has not been elucidated. Hence, a cohort of 3-, 8-, and 13-month-old immunologically unchallenged C57BL/6 wild-type mice were randomly assigned to either Control, PE, EE, or PE + EE groups and provided with either no treatment, a running wheel, a variety of plastic and wooden objects alone or in combination with a running wheel for seven weeks, respectively. Immunohistochemistry and 8-color flow cytometry were used to determine the numbers of dentate gyrus glial cells, and the proportions of CD4+ and CD8+ T cell numbers and their subsets from cervical lymph nodes, respectively. An increase in the number of IBA1+ microglia in the dentate gyrus at 5 and 10 months was observed after EE, while PE and PE + EE increased it only at 10 months. No change in astroglia number in comparison to controls were observed in any of the treatment groups. Also, all treatments induced significant differences in the proportion of specific T cell subsets, i.e., CD4+ and CD8+ T naïve (TN), central memory (TCM), and effector memory (TEM) cells. Our results suggest that in the short-term, EE is a stronger modulator of microglial and peripheral T cell subset numbers than PE and PE + EE, and the combination of short-term PE and EE has no additive effects.

Duration of Environmental Enrichment Determines Astrocyte Number and Cervical Lymph Node T Lymphocyte Proportions but Not the Microglial Number in Middle-Aged C57BL/6 Mice.

Environmental enrichment (EE) has been shown to modulate behavior and immunity. We recently reported that both short and long-term EE enhance baseline locomotion and alleviate depressive-like behavior, but only long-term EE affects locomotion adversely in a threatening environment and enhances anxiety-like behavior in middle-age mice. We have now investigated whether the observed changes in behavior after short- and long-term EE were associated with underlying immune changes. Hence, at the end of behavioral testing, mice were sacrificed, and brains and cervical lymph nodes were collected to investigate the differential effects of the duration of EE (short- and long-term) on the number of immunopositive glial cells in the dentate gyrus, CA1, CA2, and CA3 regions of the hippocampus and proportions of T cell subsets in the cervical lymph nodes using immunohistochemistry and flow cytometry, respectively. EE, regardless of duration, caused an increase in microglia number within the dentate gyrus, CA1 and CA3 hippocampal regions, but only long-term EE increased astrocytes number within the dentate gyrus and CA3 hippocampal regions. A significantly higher proportion of CD8+ naive T cells was observed after long-term EE vs. short-term EE. No significant differences were observed in the proportion of central memory and effector memory T cells or early activated CD25+ cells between any of the test groups. Our results suggest that EE, irrespective of duration, enhances the numbers of microglia, but long-term EE is required to modify astrocyte number and peripheral T cell proportions in middle-aged mice. Our findings provide new insights into the therapeutic effects of EE on various brain disorders, which may be at least partly mediated by glial and neuroimmune modulation.

Effects of aging on the motor, cognitive and affective behaviors, neuroimmune responses and hippocampal gene expression.

The known effects of aging on the brain and behavior include impaired cognition, increases in anxiety and depressive-like behaviors, and reduced locomotor activity. Environmental exposures and interventions also influence brain functions during aging. We investigated the effects of normal aging under controlled environmental conditions and in the absence of external interventions on locomotor activity, cognition, anxiety and depressive-like behaviors, immune function and hippocampal gene expression in C57BL/6 mice. Healthy mice at 4, 9, and 14 months of age underwent behavioral testing using an established behavioral battery, followed by cellular and molecular analysis using flow cytometry, immunohistochemistry, and quantitative PCR. We found that 14-month-old mice showed significantly reduced baseline locomotion, increased anxiety, and impaired spatial memory compared to younger counterparts. However, no significant differences were observed for depressive-like behavior in the forced-swim test. Microglia numbers in the dentate gyrus, as well as CD8+ memory T cells increased towards late middle age. Aging processes exerted a significant effect on the expression of 43 genes of interest in the hippocampus. We conclude that aging is associated with specific changes in locomotor activity, cognition, anxiety-like behaviors, neuroimmune responses and hippocampal gene expression.

How timely is access to palliative care medicines in the community? A mixed methods study in a UK city.

OBJECTIVE: To investigate timely access to palliative medicines/drugs (PMs) from community pharmacies to inform palliative care service delivery. DESIGN: Mixed methods in two sequential phases: (1) prospective audit of prescriptions and concurrent survey of patients/representatives collecting PMs from pharmacy and (2) interviews with community pharmacists (CPs) and other healthcare professionals (HCPs). SETTING: Five community pharmacies in Sheffield, UK and HCPs that deliver palliative care in that community. PARTICIPANTS: Phase 1: five CPs: two providing access to PMs within a locally commissioned service (LCS) and three not in the LCS; 55 patients/representatives who completed the survey when accessing PMs and phase 2: 16 HCPs, including five phase 1 CPs, were interviewed. RESULTS: The prescription audit collected information on 75 prescriptions (75 patients) with 271 individual PMs; 55 patients/representatives (73%) completed the survey. Patients/representatives reported 73% of PMs were needed urgently. In 80% of cases, patients/representatives received all PMs on the first pharmacy visit. One in five had to travel to more than one pharmacy to access PMs. The range of PMs stocked by pharmacies was the key facilitating factor. CPs reported practical issues causing difficulty keeping PMs in stock and playing a reactive role with palliative prescriptions. Confidentiality concerns were cited by other HCPs who were reluctant to share key patient information proactively with pharmacy teams. Inadequate information transfer, lack of CP integration into the care of palliative patients and poor HCP knowledge of which pharmacies stock PMs meant patients and their families were not always able to access PMs promptly. CONCLUSIONS: Consistent routine information transfer and integration of pharmacy teams in the care of palliative patients are needed to achieve timely access to PMs. Commissioners of PM access schemes should review and monitor access. HCPs need to be routinely made aware and reminded about the service and its locations.

Short-term environmental enrichment, and not physical exercise, alleviate cognitive decline and anxiety from middle age onwards without affecting hippocampal gene expression.

Physical exercise (PE) and environmental enrichment (EE) have consistently been shown to modulate behavior and neurobiological mechanisms. The current literature lacks evidence to confirm the relationship between PE and EE, if any, and whether short-term treatment with PE, EE, or PE+EE could be considered to correct age-related behavioral deficits. Three-, 8-, and 13-month-old C57BL/6 mice were assigned to either PE, EE, or PE+EE treatment groups (n = 12-16/group) for 4 weeks before behavioral testing and were compared to controls. Differential effects of the treatments on various behaviors and hippocampal gene expression were measured using an established behavioral battery and high-throughput qPCR respectively. Short-term EE enhanced locomotor activity at 9 and 14 months of age, whereas the combination of PE and EE reduced locomotor activity in the home cage at 14 months. Short-term EE also was found to reverse the age-related increase in anxiety at 9 months and spatial memory deficits at 14 months of age. Conversely, short-term PE induced spatial learning impairment and depressive-like behavior at four months but showed no effects in 9- and 14-month-old mice. PE and PE+EE, but not EE, modified the expression of several hippocampal genes at 9 months of age compared with control mice. In conclusion, short-term EE may help to alleviate age-related cognitive decline and increase in anxiety, without altering hippocampal gene expression. On the contrary, PE is detrimental at a young age for both affective-like behaviors and spatial learning and memory but showed no effects at middle and late middle age despite hippocampal gene expression alterations.

The effects of short-term and long-term environmental enrichment on locomotion, mood-like behavior, cognition and hippocampal gene expression.

BACKGROUND: Environmental enrichment (EE) has been shown to modulate behavior and hippocampal gene expression; however, the currently available literature does not explain the differential effects that may relate to the duration of EE. AIM: To investigate the differential effects of short- and long-term EE on locomotion, anxiety-, depressive- and cognition-like behaviors, and hippocampal gene expression under physiological conditions. METHODS: We assigned either short-term or long-term intervention with respective controls to healthy C57BL/6 mice (n = 12-16/group). The short-term EE group received EE for four weeks starting at eight months of age, while the long-term EE group received EE for six months starting at three months of age. Differential effects of the duration of EE on various behaviors and hippocampal gene expression at nine months of age were measured using an established behavioral battery and high-throughput RT-qPCR, respectively. RESULTS: Both short-term and long-term EE significantly enhanced locomotion in the home cage and reduced depressive-like behavior in the forced-swim test. Long-term EE, however, reduced locomotion in the open-field test. Additionally, short-term EE reduced the mean body weight and showed anxiolytic effects in the elevated-zero maze (EZM), while these effects were lost after long-term EE. There were no effects of either short-term or long-term EE on the expression of 43 hippocampal genes of interest tested at adjusted p < 0.05. CONCLUSION: Both short and long-term EE are equally beneficial for baseline locomotor activity and depressive-like behavior. However, long-term EE affects locomotion adversely in a threatening environment and is anxiogenic.

Ceasing exercise induces depression-like, anxiety-like, and impaired cognitive-like behaviours and altered hippocampal gene expression.

BACKGROUND: Regular exercise can reduce depression-, anxiety-, and impaired cognitive-like behaviours, and upregulate hippocampal genes associated with neuroplasticity. However, the effects of ceasing exercise on depression-, anxiety-, and cognitive-like behaviours, and hippocampal gene expression remain unknown. METHODS: 12-week-old C57BL/6 mice (n = 12-16/group) were randomised to six months of exercise (exercise (EXC)), four months of exercise then two months of no exercise (exercise-cessation (EC)), or no-exercise control (CONT) until aged nine months. Depression-, anxiety-, and cognitive-like behaviours were tested with the forced swim test, open field and elevated zero maze, Y-maze, and Barnes maze. The expression of 75 hippocampal genes were investigated by high-throughput quantitative polymerase chain reaction (qPCR). RESULTS: Exercise cessation increased depression- and anxiety-like behaviours, and impaired spatial learning and cognitive flexibility compared to CONT and EXC mice. 10/75 hippocampal genes were differentially expressed in EC mice, including increased expression of neurogenesis associated genes (Ntrk1), and reduced expression of immune (Il10, Gfap) and monoamine related genes (Htr1a) compared to CONT mice. Altered expression of nine genes including increased Slc6a4 and reduced Sirt1 expression were shown in EC mice compared to EXC mice. CONCLUSIONS: Exercise cessation increased depression- and anxiety-like behaviours and impaired some cognition-like behaviours with altered neurogenic, monoaminergic, and immune hippocampal gene expression consistent with the pathogenesis of depression and related anxiety described by the neurogenic, monoaminergic, and immune hypotheses of depression. Mice and humans share mammalian physiology, so these findings could be relevant to humans. These results require replication and possibly translation into high-quality pilot clinical trials.

TNF signalling via the TNF receptors mediates the effects of exercise on cognition-like behaviours.

BACKGROUND: Altered TNF levels are associated with cognitive impairment in depression, schizophrenia, bipolar disorder, and Alzheimer's disease (AD). Exercise improves cognition-like behaviours, reduces the expression of tumour necrosis factor alpha (TNF), and increases expression of the soluble TNF receptors soluble TNFR1 (sTNFR1) and sTNFR2. We suggest TNF and its receptors are involved in cognitive function and dysfunction, and investigate whether exercise mediates its effects on cognitive function via TNF and its receptors. METHODS: We utilised C57BL/6, TNF-/-, TNFR1-/-, and TNFR2-/- mice to compare exercise to non-exercise control groups to investigate whether exercise exerts its effects on various types of cognition-like behaviours via TNF and its receptors. RESULTS: Recognition memory improved with exercise in WT mice, was impaired in TNFR1-/- exercise mice, showed non-significant impairment with exercise in TNF-/- mice, and no changes in TNFR2-/- mice. In spatial learning there were exercise related improvements in WT mice, non-significant but meaningful impairments evident in TNFR1-/- exercise mice, modest improvement in TNF-/- exercise mice, and potentially meaningful non-significant improvements in TNFR2-/- exercise mice. Moreover, WT and TNFR2-/- mice displayed noteworthy non-significant improvements in spatial memory, whereas TNFR1-/- exercise mice demonstrated non-significant spatial memory impairment. Exercise did not alter cognitive flexibility in any strain. DISCUSSION: TNF receptor signalling via the TNFR1 and TNFR2 appears to mediate the effects of exercise on cognitive-like behaviours. The potential for exercise to regulate human TNF and TNF signalling and cognitive dysfunction needs investigation under inflammatory conditions including depression and neuropsychiatric disorders.

Exercise related anxiety-like behaviours are mediated by TNF receptor signaling, but not depression-like behaviours.

Depression can involve disrupted pro-inflammatory TNF signaling via the TNF receptors TNFR1 and TNFR2, or the soluble TNF receptors sTNFR1 and sTNFR2. However, exercise might attenuate pro-inflammatory signaling in depression and related anxiety. We hypothesized that six months voluntary wheel running exercise would improve depression-like and anxiety-like behaviours in WT and TNFR1-/- mice, but not in TNF-/- and TNFR2-/- mice compared to their respective control mice. METHODS: We investigated the effects of six months voluntary wheel running exercise on open field (OF) and elevated zero maze (EZM) anxiety-like behaviours, and forced swim test (FST) depression-like behaviours in control and exercise WT, TNF-/-, TNFR1-/-, and TNFR2-/- mice with two-way ANOVAs. RESULTS: Exercise reduced of anxiety-like behaviours in TNFR2-/- exercise mice compared to their respective controls. Compared to WT control mice, WT exercise mice displayed significantly reduced EZM anxiety-like behaviours. There were no exercise related changes in FST immobility time. Between-strains analyses found WT control and exercise mice displayed reduced EZM anxiety-like behaviours compared to TNF-/- and TNFR1-/- control and exercise mice, and WT exercise mice displayed reduced anxiety-like behavior compared to TNFR2-/- exercise mice. DISCUSSION: Exercise associated TNFR1 and TNFR2 signaling in concert in WT exercise mice mediated reductions in aspects of anxiety-like behaviours. These findings are consistent with the current view that imbalances in TNF signaling are involved in disrupted affect. Additional studies are needed to further explore the roles of exercise related TNFR1 and TNFR2 signaling in anxiety-like and depression-like behaviours.

Does ceasing exercise induce depressive symptoms? A systematic review of experimental trials including immunological and neurogenic markers.

BACKGROUND: Regular exercise in adults improves depressive symptoms (DS) and major depressive disorder (MDD), however the clinical effects of ceasing exercise are largely unknown. METHODS: Seven databases were searched from inception to December 2017. Eligibility criteria included English language studies investigating the effects of ceasing exercise on DS or MDD in regularly active adults with or without prior DS or MDD. Blood based markers related to exercise cessation (EC) were assessed, if recorded. Studies investigating exercise follow-up periods were excluded. RESULTS: No studies investigated EC in MDD. Six studies including two RCTS and three studies investigating neurogenic and immune biological markers associated with DS met inclusion criteria (152 healthy adults, females n = 50/32.89%). Compared to baseline, EC increased DS after three days, one week, and two weeks. Female participants had significantly more DS than male participants. Following EC, no changes in brain derived neurotrophic factor (BDNF) or tumour necrosis factor alpha (TNF) were evident, however C-reactive protein (CRP) at week one and interleukin 6 (IL6) at week two were reduced. LIMITATIONS: Quality concerns including risks of attrition and reporting bias limit our confidence in these results. CONCLUSIONS: Ceasing regular exercise increases DS in healthy adults, with greater DS in females than males. Contrary to the cytokine/inflammatory hypothesis of depression, DS were associated with reduced CRP and IL6 and without increased TNF. High quality trials are needed to extend this field of research in both healthy and MDD populations.