Lipid homeostasis and inflammatory activation are disturbed in classically activated macrophages with peroxisomal β-oxidation deficiency

Macrophage activation is characterized by pronounced metabolic adaptation. Classically activated macrophages show decreased rates of mitochondrial fatty acid oxidation and oxidative phosphorylation and acquire a glycolytic state together with their pro-inflammatory phenotype. In contrast, alternatively activated macrophages require oxidative phosphorylation and mitochondrial fatty acid oxidation for their anti-inflammatoryfunction. Although it is evident that mitochondrial metabolism is regulated during macrophage polarization and essential for macrophagefunction, little is known on the regulation and role of peroxisomal -oxidation during macrophage activation. In this study, we show that peroxisomal -oxidation is strongly decreased in classically activated bone-marrow-derived macrophages (BMDM) and mildly induced in alternatively activated BMDM. To examine the role of peroxisomal -oxidation in macrophages, we used Mfp2(-/-) BMDM lacking the key enzyme of this pathway. Impairment of peroxisomal -oxidation in Mfp2(-/-) BMDM did not cause lipid accumulation but rather an altered distribution of lipid species with very-long-chain fatty acids accumulating in the triglyceride and phospholipid fraction. These lipid alterations in Mfp2(-/-) macrophages led to decreased inflammatory activation of Mfp2(-/-) BMDM and peritoneal macrophages evidenced by impaired production of several inflammatory cytokines and chemokines, but did not affect anti-inflammatory polarization. The disturbed inflammatory responses of Mfp2(-/-) macrophages did not affect immune cell infiltration, as mice with selective elimination of MFP2 from myeloid cells showed normal monocyte and neutrophil influx upon challenge with zymosan. Together, these data demonstrate that peroxisomal -oxidation is involved in fine-tuning the phenotype of macrophages, probably by influencing the dynamic lipid profile during macrophage polarization

Peroxisome deficiency but not the defect in ether lipid synthesis causes activation of the innate immune system and axonal loss in the central nervous system

Background: Mice with peroxisome deficiency in neural cells (Nestin-Pex5 −/− ) develop a neurodegenerative phenotype leading to motor and cognitive disabilities and early death. Major pathologies at the end stage of disease include severe demyelination, axonal degeneration and neuroinflammation. We now investigated the onset and progression of these pathological processes, and their potential interrelationship. In addition, the putative role of oxidative stress, the impact of plasmalogen depletion on the neurodegenerative phenotype, and the consequences of peroxisome elimination in the postnatal period were studied. Methods: Immunohistochemistry in association with gene expression analysis was performed on Nestin-Pex5 −/− mice to document demyelination, axonal damage and neuroinflammation. Also Gnpat −/− mice, with selective plasmalogen deficiency and CMV-Tx-Pex5 −/− mice, with tamoxifen induced generalized loss of peroxisomes were analysed. Results: Activation of the innate immune system is a very early event in the pathological process in Nestin-Pex5 −/− mice which evolves in chronic neuroinflammation. The complement factor C1q, one of the earliest up regulated transcripts, was expressed on neurons and oligodendrocytes but not on microglia. Transcripts of other pro- and anti-inflammatory genes and markers of phagocytotic activity were already significantly induced before detecting pathologies with immunofluorescent staining. Demyelination, macrophage activity and axonal loss co-occurred throughout the brain. As in patients with mild peroxisome biogenesis disorders who develop regressive changes, demyelination in cerebellum and brain stem preceded major myelin loss in corpus callosum of both Nestin-Pex5 −/− and CMV-Tx-Pex5 −/− mice. These lesions were not accompanied by generalized oxidative stress throughout the brain. Although Gnpat −/− mice displayed dysmyelination and Purkinje cell axon damage in cerebellum, confirming previous observations, no signs of inflammation or demyelination aggravating with age were observed. Conclusions: Peroxisome inactivity triggers a fast neuroinflammatory reaction, which is not solely due to the depletion of plasmalogens. In association with myelin abnormalities this causes axon damage and loss

An evidence-based approach to the use of telehealth in long-term health conditions: development of an intervention and evaluation through pragmatic randomised controlled trials in patients with depression or raised cardiovascular risk

Background: Health services internationally are exploring the potential of telehealth to support the management of the growing number of people with long-term conditions (LTCs). Aim: To develop, implement and evaluate new care programmes for patients with LTCs, focusing on two common LTCs as exemplars: depression or high cardiovascular disease (CVD) risk. Methods Development: We synthesised quantitative and qualitative evidence on the effectiveness of telehealth for LTCs, conducted a qualitative study based on interviews with patients and staff and undertook a postal survey to explore which patients are interested in different forms of telehealth. Based on these studies we developed a conceptual model [TElehealth in CHronic disease (TECH) model] as a framework for the development and evaluation of the Healthlines Service for patients with LTCs. Implementation: The Healthlines Service consisted of regular telephone calls to participants from health information advisors, supporting them to make behaviour change and to use tailored online resources. Advisors sought to optimise participants’ medication and to improve adherence. Evaluation: The Healthlines Service was evaluated with linked pragmatic randomised controlled trials comparing the Healthlines Service plus usual care with usual care alone, with nested process and economic evaluations. Participants were adults with depression or raised CVD risk recruited from 43 general practices in three areas of England. The primary outcome was response to treatment and the secondary outcomes included anxiety (depression trial), individual risk factors (CVD risk trial), self-management skills, medication adherence, perceptions of support, access to health care and satisfaction with treatment. Trial results Depression trial: In total, 609 participants were randomised and the retention rate was 86%. Response to treatment [Patient Health Questionnaire 9-items (PHQ-9) reduction of ≥ 5 points and score of < 10 after 4 months] was higher in the intervention group (27%, 68/255) than in the control group (19%, 50/270) [odds ratio 1.7, 95% confidence interval (CI) 1.1 to 2.5; p = 0.02]. Anxiety also improved. Intervention participants reported better access to health support, greater satisfaction with treatment and small improvements in self-management, but not improved medication adherence. CVD risk trial: In total, 641 participants were randomised and the retention rate was 91%. Response to treatment (maintenance of/reduction in QRISK®2 score after 12 months) was higher in the intervention group (50%, 148/295) than in the control group (43%, 124/291), which does not exclude a null effect (odds ratio 1.3, 95% CI 1.0 to 1.9; p = 0.08). The intervention was associated with small improvements in blood pressure and weight, but not smoking or cholesterol. Intervention participants were more likely to adhere to medication, reported better access to health support and greater satisfaction with treatment, but few improvements in self-management. The Healthlines Service was likely to be cost-effective for CVD risk, particularly if the benefits are sustained, but not for depression. The intervention was implemented largely as planned, although initial delays and later disruption to delivery because of the closure of NHS Direct may have adversely affected participant engagement. Conclusion: The Healthlines Service, designed using an evidence-based conceptual model, provided modest health benefits and participants valued the better access to care and extra support provided. This service was cost-effective for CVD risk but not depression. These findings of small benefits at extra cost are consistent with previous pragmatic research on the implementation of comprehensive telehealth programmes for LTCs

Neuro-immune interaction and the regulation of intestinal immune homeostasis

Many essential gastrointestinal functions, including motility, secretion and blood flow are regulated by the autonomic nervous system (ANS), both through intrinsic enteric neurons and extrinsic (sympathetic and parasympathetic) innervation. Recently identified neuro-immune mechanisms, in particular the interplay between enteric neurons and muscularis macrophages, are now considered to be essential for fine-tuning peristalsis. These findings shed new light on how intestinal immune cells can support enteric nervous function. In addition, both intrinsic and extrinsic neural mechanisms control intestinal immune homeostasis in different layers of the intestine, mainly by affecting macrophage activation through neurotransmitter release. In this mini-review, we discuss recent insights on immunomodulation by intrinsic enteric neurons and extrinsic innervation, with a particular focus on intestinal macrophages. In addition, we discuss the relevance of these novel mechanisms for intestinal immune homeostasis in physiological and pathological conditions, mainly focusing on motility disorders (gastroparesis and post-operative ileus) and inflammatory disorders (colitis).status: publishe

Generalised and neural restricted peroxisomal MFP2 deficiency causes demyelination and motoric deficits but neuroinflammatory responses are distinct

status: publishe

Long-Lived Yolk-Sac Derived Macrophages Interact with Myenteric and Submucosal Neurons

status: publishe

The vagus nerve in appetite regulation, mood and intestinal inflammation

Although the gastrointestinal (GI) tract contains intrinsic neural plexuses that allow a significant degree of independent control over GI functions, the central nervous system provides extrinsic neural inputs that modulate, regulate and integrate these functions. In particular, the vagus nerve (VN) provides the parasympathetic innervation to the GI tract, co-ordinates the complex interactions between central and peripheral neural control mechanisms. This review will discuss the physiological roles of the afferent (sensory) and motor (efferent) vagus in regulation of appetite, mood and the immune system, as well as the pathophysiological outcomes of VN dysfunction resulting in obesity, mood disorders and inflammation. The therapeutic potential of VN modulation to attenuate or reverse these pathophysiological outcomes and restore autonomic homeostasis will also be discussed.publisher: Elsevier articletitle: The Vagus Nerve in Appetite Regulation, Mood, and Intestinal Inflammation journaltitle: Gastroenterology articlelink: http://dx.doi.org/10.1053/j.gastro.2016.10.046 content_type: article copyright: © 2017 by the AGA Institute. Published by Elsevier Inc.status: publishe

Long-lived Yolk-sac Derived Intestinal Macrophages Interact with Submucosal and Myenteric Neurons

status: publishe

Peroxisomal Disorders: A Review on Cerebellar Pathologies

Peroxisomes are organelles with diverse metabolic tasks including essential roles in lipid metabolism. They are of utmost importance for the normal functioning of the nervous system as most peroxisomal disorders are accompanied with neurological symptoms. Remarkably, the cerebellum exquisitely depends on intact peroxisomal function both during development and adulthood. In this review, we cover all aspects of cerebellar pathology that were reported in peroxisome biogenesis disorders and in diseases caused by dysfunction of the peroxisomal α-oxidation, β-oxidation or ether lipid synthesis pathways. We also discuss the phenotypes of mouse models in which cerebellar pathologies were recapitulated and search for connections with the metabolic abnormalities. It becomes increasingly clear that besides the most severe forms of peroxisome dysfunction that are associated with developmental cerebellar defects, milder impairments can give rise to ataxia later in life.status: publishe