Sleep modulates haematopoiesis and protects against atherosclerosis

Granulopoiesis and Neutrophil Homeostasis: A Metabolic, Daily Balancing Act

Granulopoiesis is part of the hematopoietic hierarchic architecture, where hematopoietic stem cells give rise to highly proliferative multipotent and lineage-committed granulocytic progenitor cells that differentiate into unipotent neutrophil progenitors. Given their short lifespan, neutrophils are rapidly cleared from circulation through specialized efferocytic macrophages. Together with an intrinsic clock, these processes contribute to circadian fluctuations, preserving self-tolerance and protection against invading pathogens. However, metabolic perturbation of granulopoiesis and neutrophil homeostasis can result in low-grade chronic inflammation, as observed with aging. During acute pathogenic infections, hematopoiesis can also be switched into emergency mode, which has been recently associated with significant neutrophil functional heterogeneity. This review focuses on a new reassessment of regulatory mechanisms governing neutrophil production, life-cycle, and diversity in health and disease.

Actigraphy-estimated sleep and 24-hour activity rhythms and the risk of dementia

Introduction

We investigated and compared associations of objective estimates of sleep and 24‐hour activity rhythms using actigraphy with risk of dementia.

Methods

We included 1322 non‐demented participants from the prospective, population‐based Rotterdam Study cohort with valid actigraphy data (mean age 66 ± 8 years, 53% women), and followed them for up to 11.2 years to determine incident dementia.

Results

During follow‐up, 60 individuals developed dementia, of which 49 had Alzheimer's disease (AD). Poor sleep as indicated by longer sleep latency, wake after sleep onset, and time in bed and lower sleep efficiency, as well as an earlier “lights out” time, were associated with increased risk of dementia, especially AD. We found no associations of 24‐hour activity rhythms with dementia risk.

Discussion

Poor sleep, but not 24‐hour activity rhythm disturbance, is associated with increased risk of dementia. Actigraphy‐estimated nighttime wakefulness may be further targeted in etiologic or risk prediction studies.

Summarizing 2019 in Cardiovascular Prevention Using the Johns Hopkins Ciccarone Center for the Prevention of Cardiovascular Disease's 'ABC's Approach

In 2019, Preventive Cardiology welcomed many exciting discoveries that improve our ability to reduce the burden of cardiovascular disease (CVD) nationwide. Not only did 2019 further clarify how various environmental exposures and innate and acquired risk factors contribute to the development of CVD, but it also provided new guidelines and therapeutics to more effectively manage existing CVD. Cardiovascular disease prevention requires the prioritization of early and effective detection of CVD in order to implement aggressive lifestyle and pharmacologic therapies, which can slow, halt, or even reverse the progression of the disease. To help streamline and simplify the process of CVD prevention, The Johns Hopkins Ciccarone Center for the Prevention of Cardiovascular Disease has historically adopted an ‘ABC’ approach, which focuses on optimizing individual CVD risk through lifestyle, behavioral, and pharmacologic interventions. Given the practice changing research and innovation from the past year, this article intends to summarize the Ciccarone Center’s key takeaways from CVD prevention in 2019 utilizing our expanded ‘ABC’ approach.

The Roles of Monocyte and Monocyte-Derived Macrophages in Common Brain Disorders

The brain is the most important and complex organ in most living creatures which serves as the center of the nervous system. The function of human brain includes controlling of the motion of the body and different organs and maintaining basic homeostasis. The disorders of the brain caused by a variety of reasons often severely impact the patients' normal life or lead to death in extreme cases. Monocyte is an important immune cell which is often recruited to the brain in a number of brain disorders. However, the role of monocytes may not be simply described as beneficial or detrimental. It significantly depends on the disease models and the stages of disease progression. In this review, we summarized the current knowledge about the role of monocytes and monocyte-derived macrophages during several common brain disorders. Major focuses include ischemic stroke, Alzheimer's disease, multiple sclerosis, intracerebral hemorrhage, and insomnia. The recruitment, differentiation, and function of monocyte in these diseases are reviewed.

Broken sleep predicts hardened blood vessels

Why does poor-quality sleep lead to atherosclerosis? In a diverse sample of over 1,600 individuals, we describe a pathway wherein sleep fragmentation raises inflammatory-related white blood cell counts (neutrophils and monocytes), thereby increasing atherosclerosis severity, even when other common risk factors have been accounted for. Improving sleep quality may thus represent one preventive strategy for lowering inflammatory status and thus atherosclerosis risk, reinforcing public health policies focused on sleep health.

Why does poor quality sleep correlate with cardiovascular disease? A large population-based study suggests that fragmented sleep contributes to atherosclerosis in humans by increasing inflammatory-related activity of white blood cells.

Sleep Loss Can Cause Death through Accumulation of Reactive Oxygen Species in the Gut

The view that sleep is essential for survival is supported by the ubiquity of this behavior, the apparent existence of sleep-like states in the earliest animals, and the fact that severe sleep loss can be lethal. The cause of this lethality is unknown. Here we show, using flies and mice, that sleep deprivation leads to accumulation of reactive oxygen species (ROS) and consequent oxidative stress, specifically in the gut. ROS are not just correlates of sleep deprivation but drivers of death: their neutralization prevents oxidative stress and allows flies to have a normal lifespan with little to no sleep. The rescue can be achieved with oral antioxidant compounds or with gut-targeted transgenic expression of antioxidant enzymes. We conclude that death upon severe sleep restriction can be caused by oxidative stress, that the gut is central in this process, and that survival without sleep is possible when ROS accumulation is prevented. VIDEO ABSTRACT.

Improving translational research in sex-specific effects of comorbidities and risk factors in ischaemic heart disease and cardioprotection: position paper and recommendations of the ESC Working Group on Cellular Biology of the Heart

Ischaemic heart disease (IHD) is a complex disorder and a leading cause of death and morbidity in both men and women. Sex, however, affects several aspects of IHD, including pathophysiology, incidence, clinical presentation, diagnosis as well as treatment and outcome. Several diseases or risk factors frequently associated with IHD can modify cellular signalling cascades, thus affecting ischaemia/reperfusion injury as well as responses to cardioprotective interventions. Importantly, the prevalence and impact of risk factors and several comorbidities differ between males and females, and their effects on IHD development and prognosis might differ according to sex. The cellular and molecular mechanisms underlying these differences are still poorly understood, and their identification might have important translational implications in the prediction or prevention of risk of IHD in men and women. Despite this, most experimental studies on IHD are still undertaken in animal models in the absence of risk factors and comorbidities, and assessment of potential sex-specific differences are largely missing. This ESC WG Position Paper will discuss: (i) the importance of sex as a biological variable in cardiovascular research, (ii) major biological mechanisms underlying sex-related differences relevant to IHD risk factors and comorbidities, (iii) prospects and pitfalls of preclinical models to investigate these associations, and finally (iv) will provide recommendations to guide future research. Although gender differences also affect IHD risk in the clinical setting, they will not be discussed in detail here.

Neuroimmune interactions in cardiovascular diseases

Our body is continuously in contact with external stimuli that need a fine integration with the internal milieu in order to maintain the homoeostasis. Similarly, perturbations of the internal environment are responsible for the alterations of the physiological mechanisms regulating our main functions. The nervous system and the immune system represent the main interfaces between the internal and the external environment. In carrying out these functions, they share many similarities, being able to recognize, integrate, and organize responses to a wide variety of stimuli, with the final aim to re-establish the homoeostasis. The autonomic nervous system, which collectively refers to the ensemble of afferent and efferent neurons that wire the central nervous system with visceral effectors throughout the body, is the prototype system controlling the homoeostasis through reflex arches. On the other hand, immune cells continuously patrol our body against external enemies and internal perturbations, organizing acute responses and forming memory for future encounters. Interesting to notice, the integration of the two systems provides a further unique opportunity for fine tuning of our body's homoeostasis. In fact, the autonomic nervous system guides the development of lymphoid and myeloid organs, as well as the deployment of immune cells towards peripheral tissues where they can affect and control several physiological functions. In turn, every specific immune cell type can contribute to regulate neural circuits involved in cardiovascular function, metabolism, and inflammation. Here, we review current understanding of the cross-regulation between these systems in cardiovascular diseases.

From Focal Lipid Storage to Systemic Inflammation: JACC Review Topic of the Week

Concepts of atherogenesis have evolved considerably with time. Early animal experiments showed that a cholesterol-rich diet could induce fatty lesion formation in arteries. The elucidation of lipoprotein metabolism ultimately led to demonstrating the clinical benefits of lipid lowering. The view of atheromata as bland accumulations of smooth muscle cells that elaborated an extracellular matrix that could entrap lipids then expanded to embrace inflammation as providing pathways that could link risk factors to atherogenesis. The characterization of leukocyte adhesion molecules and their control by proinflammatory cytokines, the ability of chemokines to recruit leukocytes, and the identification of inflammatory cell subtypes in lesions spurred the unraveling of innate and adaptive immune pathways that contribute to atherosclerosis and its thrombotic complications. Such pathophysiologic insights have led to the identification of biomarkers that can define categories of risk and direct therapies and to the development of new treatments.

Sleep Supports Memory and Learning: Implications for Clinical Practice in Speech-Language Pathology

Purpose This tutorial aims to draw attention to the interactions among memory, sleep, and therapy potential and to increase awareness and knowledge in the field of speech-language pathology of the potential impact of sleep as a mediating or moderating factor in promoting therapeutic outcome. Method We highlight key findings from the literature on the cognitive neuroscience of memory, the neurophysiology of sleep, how sleep supports memory, and how sleep disruption affects memory and learning abilities in populations commonly served in speech-language pathology. Results Research increasingly points to the critical importance of sleep quality and quantity to memory and learning, and sleep disruption is linked to deficits in functional cognition that may limit our clients' ability to benefit from speech pathology interventions. Conclusions As a field dedicated to promoting memory, learning, and relearning through our interventions, any systemic factors that affect these abilities demand our attention. Although speech-language pathologists do not treat sleep disturbance, we play a critical role in recognizing the signs and symptoms of sleep disturbance and making appropriate referrals, as undiagnosed and untreated sleep disturbance can have serious impacts on success in therapeutic contexts. By considering how related factors affect memory and learning, we have the opportunity to take a whole client approach to maximizing our clients' therapy potential and functional progress.

Interactions between season of birth, chronological age and genetic polymorphisms in determining later-life chronotype

Human chronotype, the temporal pattern of daily behaviors, is influenced by postnatal seasonal programming and ageing. The aim of this study was to investigate genetic variants that are associated with season of birth programming and longitudinal chronotype change. Longitudinal sleep timing and genotype data from 1449 participants were collected for up to 27 years. Gene-environment interaction analysis was performed for 445 candidate single nucleotide polymorphisms that have previously been associated with chronotype. Associations were tested using linear mixed model. We identified 67 suggestively significant genomic loci that have genotype-ageing interaction and 25 genomic loci that may have genotype-season of birth interaction in determining chronotype. We attempted to replicate the results using longitudinal data of the UK Biobank from approximately 30,000 participants. Biological functions of these genes suggest that epigenetic regulation of gene expression and neural development may have roles in these processes. The strongest associated gene for sleep trajectories was ALKBH5, which has functions of DNA repair and epigenetic regulation. A potential candidate gene for postnatal seasonal programming was SIRT1, which has previously been implicated in postnatal programming, ageing and longevity. Genetic diversity may explain the heterogeneity in ageing-related change of sleep timing and postnatal environmental programming of later-life chronotype.

Modifiable Cardiovascular Risk, Hematopoiesis, and Innate Immunity

Unhealthy diet, lack of exercise, psychosocial stress, and insufficient sleep are increasingly prevalent modifiable risk factors for cardiovascular disease. Accumulating evidence indicates that these risk factors may fuel chronic inflammatory processes that are active in atherosclerosis and lead to myocardial infarction and stroke. In concert with hyperlipidemia, maladaptive immune system activities can contribute to disease progression and increase the probability of adverse events. In this review, we discuss recent insight into how the above modifiable risk factors influence innate immunity. Specifically, we focus on pathways that raise systemic myeloid cell numbers and modulate immune cell phenotypes, reviewing hematopoiesis, leukocyte trafficking, and innate immune cell accumulation in cardiovascular organs. Often, relevant mechanisms that begin with lifestyle choices and lead to cardiovascular events span multiple organ systems, including the central nervous, endocrine, metabolic, hematopoietic, immune and, finally, the cardiovascular system. We argue that deciphering such pathways provides not only support for preventive interventions but also opportunities to develop biomimetic immunomodulatory therapeutics that mitigate cardiovascular inflammation.

Hematopoiesis and Cardiovascular Disease

A central feature of atherosclerosis, the most prevalent chronic vascular disease and root cause of myocardial infarction and stroke, is leukocyte accumulation in the arterial wall. These crucial immune cells are produced in specialized niches in the bone marrow, where a complex cell network orchestrates their production and release. A growing body of clinical studies has documented a correlation between leukocyte numbers and cardiovascular disease risk. Understanding how leukocytes are produced and how they contribute to atherosclerosis and its complications is, therefore, critical to understanding and treating the disease. In this review, we focus on the key cells and products that regulate hematopoiesis under homeostatic conditions, during atherosclerosis and after myocardial infarction.

Neuromodulation of the Pineal Gland via Electrical Stimulation of Its Sympathetic Innervation Pathway

Stimulation of the pineal gland via its sympathetic innervation pathway results in the production of N-acetylserotonin and melatonin. Melatonin has many therapeutic roles and is heavily implicated in the regulation of the sleep-wake cycle. In addition, N-acetylserotonin has recently been reported to promote neurogenesis in the brain. Upregulation of these indoleamines is possible via neuromodulation of the pineal gland. This is achieved by electrical stimulation of structures or fibres in the pineal gland sympathetic innervation pathway. Many studies have performed such pineal neuromodulation using both invasive and non-invasive methods. However, the effects of various experimental variables and stimulation paradigms has not yet been reviewed and evaluated. This review summarises these studies and presents the optimal experimental protocols and stimulation parameters necessary for maximal upregulation of melatonin metabolic output.

Associations of Benzodiazepine With Adverse Prognosis in Heart Failure Patients With Insomnia

Background

The prognostic impact of benzodiazepines has been unclear in patients with heart failure (HF).

Methods and Results

This was a historical observational cohort study. A total of 826 patients who had been hospitalized for HF and were being treated for insomnia with either benzodiazepines or Z‐drugs (zolpidem, zopiclone, or eszopiclone), were enrolled and divided on the basis of their hypnotics: benzodiazepine group (n=488 [59.1%]) and Z group (n=338 [40.9%]). We compared the patient characteristics and postdischarge prognosis between the groups. The primary end points were rehospitalization for HF and cardiac death. The benzodiazepine group was older (age, 72.0 versus 69.0 years; P=0.010), had a higher prevalence of depression (17.4% versus 8.9%; P<0.001), and showed a higher use of loop diuretics (77.9% versus 67.8%; P=0.001). In the laboratory data, the benzodiazepine group demonstrated lower levels of hemoglobin (12.3 versus 13.0 g/dL; P=0.001), sodium (139.0 versus 140.0 mEq/L; P=0.018), and albumin (3.7 versus 3.9 g/dL; P=0.003). Kaplan‐Meier analysis showed that both end points were higher in the benzodiazepine group (rehospitalization for HF, log‐rank P=0.001; cardiac death, log‐rank P=0.043). Multiple Cox proportional hazard analysis revealed that the use of benzodiazepines was an independent predictor of rehospitalization for HF (hazard ratio, 1.530; 95% CI, 1.025–2.284; P=0.038). Furthermore, rehospitalization for HF was higher in the benzodiazepine group after propensity score matching (log‐rank P=0.036).

Conclusions

Benzodiazepine is associated with higher risk of rehospitalization for HF compared with Z‐drugs in patients with HF.

Neutrophils as regulators of cardiovascular inflammation

Neutrophils have traditionally been viewed as bystanders or biomarkers of cardiovascular disease. However, studies in the past decade have demonstrated the important functions of neutrophils during cardiovascular inflammation and repair. In this Review, we discuss the influence of traditional and novel cardiovascular risk factors on neutrophil production and function. We then appraise the current knowledge of the contribution of neutrophils to the different stages of atherosclerosis, including atherogenesis, plaque destabilization and plaque erosion. In the context of cardiovascular complications of atherosclerosis, we highlight the dichotomous role of neutrophils in pathogenic and repair processes in stroke, heart failure, myocardial infarction and neointima formation. Finally, we emphasize how detailed knowledge of neutrophil functions in cardiovascular homeostasis and disease can be used to generate therapeutic strategies to target neutrophil numbers, functional status and effector mechanisms.

Perfect timing: circadian rhythms, sleep, and immunity - an NIH workshop summary

Recent discoveries demonstrate a critical role for circadian rhythms and sleep in immune system homeostasis. Both innate and adaptive immune responses - ranging from leukocyte mobilization, trafficking, and chemotaxis to cytokine release and T cell differentiation -are mediated in a time of day-dependent manner. The National Institutes of Health (NIH) recently sponsored an interdisciplinary workshop, "Sleep Insufficiency, Circadian Misalignment, and the Immune Response," to highlight new research linking sleep and circadian biology to immune function and to identify areas of high translational potential. This Review summarizes topics discussed and highlights immediate opportunities for delineating clinically relevant connections among biological rhythms, sleep, and immune regulation.

Self-reported sleep quality as prognostic for survival in lung cancer patients

Purpose

Sleep is essential for life, as well as having a major impact on quality of life. Not much attention has been given to this important factor in the care of lung cancer patients.

Patients and Methods

We retrospectively analyzed a cohort of 404 lung cancer patients treated in our institute between 2010 and 2018. Data about sleep quality, distress and pain were self-reported by questionnaires administered to patients at their first clinic visit to the Institute of Oncology. Sex, age, histology, stage, smoking and marital status were extracted from the patients’ charts. Uni- and multi-variate analyses were carried out to evaluate the correlation of these factors with survival.

Results

Most patients reported some level of distress and pain. Sleep abnormalities were reported by 58.7% of patients. Distress, pain and bad sleep were correlated with shorter survival in univariate analyses; however, only sleep remained associated with survival in multivariate analysis. Patients reporting bad sleep had a median survival of 16 months, compared to 27 months for patients reporting good sleep (hazard ratio 1.83, 95% C.I. 1.27–2.65). Frequent arousals at night were more tightly correlated with survival than difficulty falling asleep.

Conclusion

Sleep quality, as reported by lung cancer patients, is highly correlated with survival. Further studies are required to comprehend whether poor sleep quality is directly impacting survival or is a result of the cancer aggressiveness and patients’ conditions.

The year in cardiology: cardiovascular prevention

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Sleep deficiency and chronic pain: potential underlying mechanisms and clinical implications

Pain can be both a cause and a consequence of sleep deficiency. This bidirectional relationship between sleep and pain has important implications for clinical management of patients, but also for chronic pain prevention and public health more broadly. The review that follows will provide an overview of the neurobiological evidence of mechanisms thought to be involved in the modulation of pain by sleep deficiency, including the opioid, monoaminergic, orexinergic, immune, melatonin, and endocannabinoid systems; the hypothalamus-pituitary-adrenal axis; and adenosine and nitric oxide signaling. In addition, it will provide a broad overview of pharmacological and non-pharmacological approaches for the management of chronic pain comorbid with sleep disturbances and for the management of postoperative pain, as well as discuss the effects of sleep-disturbing medications on pain amplification.

Role of neutrophils in ischemic heart failure

Amplified innate leukocytes (neutrophils and monocytes/macrophages) are associated with advanced ischemic and non-ischemic heart failure (HF). Intensified neutrophilic leukocytosis (neutrophilia) and sustained activation of neutrophils is the predominant factor that determines over activated inflammation in acute HF and the outcome of long-term chronic HF. After heart attack, the first wave of innate responsive and short-lived neutrophils is essential for the initiation of inflammation, resolution of inflammation, and cardiac repair, however uncontrolled and long-term activation of neutrophils leads to collateral damage of myocardium. In the presented review, we highlighted the interactive and integrative role of neutrophil phenotypes in cellular and molecular events of ischemic HF. In addition, we discussed the current, nonimmune, immune, and novel paradigms of neutrophils in HF associated with differential factors with a specific interest in non-resolving inflammation and resolution physiology.

Formononetin attenuates atherosclerosis via regulating interaction between KLF4 and SRA in apoE-/- mice

Background and Purpose: Atherosclerosis is an underlying cause of coronary heart disease. Foam cell, a hallmark of atherosclerosis, is prominently derived from monocyte-differentiated macrophage, and vascular smooth muscle cells (VSMCs) through unlimitedly phagocytizing oxidized low-density lipoprotein (oxLDL). Therefore, the inhibition of monocyte adhesion to endothelium and uptake of oxLDL might be a breakthrough point for retarding atherosclerosis. Formononetin, an isoflavone extracted from Astragalus membranaceus, has exhibited multiple inhibitory effects on proatherogenic factors, such as obesity, dyslipidemia, and inflammation in different animal models. However, its effect on atherosclerosis remains unknown. In this study, we determined if formononetin can inhibit atherosclerosis and elucidated the underlying molecular mechanisms.

Methods: ApoE deficient mice were treated with formononetin contained in high-fat diet for 16 weeks. After treatment, mouse aorta, macrophage and serum samples were collected to determine lesions, immune cell profile, lipid profile and expression of related molecules. Concurrently, we investigated the effect of formononetin on monocyte adhesion, foam cell formation, endothelial activation, and macrophage polarization in vitro and in vivo.

Results: Formononetin reduced en face and aortic root sinus lesions size. Formononetin enhanced lesion stability by changing the composition of plaque. VSMC- and macrophage-derived foam cell formation and its accumulation in arterial wall were attenuated by formononetin, which might be attributed to decreased SRA expression and reduced monocyte adhesion. Formononetin inhibited atherogenic monocyte adhesion and inflammation. KLF4 negatively regulated the expression of SRA at transcriptional and translational level.

Conclusions: Our study demonstrate that formononetin can substantially attenuate the development of atherosclerosis via regulation of interplay between KLF4 and SRA, which suggests the formononetin might be a novel therapeutic approach for inhibition of atherosclerosis.

Disruption of circadian rhythm by alternating light-dark cycles aggravates atherosclerosis development in APOE*3-Leiden.CETP mice

Disruption of circadian rhythm by means of shift work has been associated with cardiovascular disease in humans. However, causality and underlying mechanisms have not yet been established. In this study, we exposed hyperlipidemic APOE*3-Leiden.CETP mice to either regular light-dark cycles, weekly 6 hours phase advances or delays, or weekly alternating light-dark cycles (12 hours shifts), as a well-established model for shift work. We found that mice exposed to 15 weeks of alternating light-dark cycles displayed a striking increase in atherosclerosis, with an approximately twofold increase in lesion size and severity, while mice exposed to phase advances and delays showed a milder circadian disruption and no significant effect on atherosclerosis development. We observed a higher lesion macrophage content in mice exposed to alternating light-dark cycles without obvious changes in plasma lipids, suggesting involvement of the immune system. Moreover, while no changes in the number or activation status of circulating monocytes and other immune cells were observed, we identified increased markers for inflammation, oxidative stress, and chemoattraction in the vessel wall. Altogether, this is the first study to show that circadian disruption by shifting light-dark cycles directly aggravates atherosclerosis development.

Sleep deprivation of rats increases postsurgical expression and activity of L-type calcium channel in the dorsal root ganglion and slows recovery from postsurgical pain

Perioperative sleep disturbance is a risk factor for persistent pain after surgery. Clinical studies have shown that patients with insufficient sleep before and after surgery experience more intense and long-lasting postoperative pain. We hypothesize that sleep deprivation alters L-type calcium channels in the dorsal root ganglia (DRG), thus delaying the recovery from post-surgical pain. To verify this hypothesis, and to identify new predictors and therapeutic targets for persistent postoperative pain, we first established a model of postsurgical pain with perioperative sleep deprivation (SD) by administering hind paw plantar incision to sleep deprivation rats. Then we conducted behavioral tests, including tests with von Frey filaments and a laser heat test, to verify sensory pain, measured the expression of L-type calcium channels using western blotting and immunofluorescence of dorsal root ganglia (an important neural target for peripheral nociception), and examined the activity of L-type calcium channels and neuron excitability using electrophysiological measurements. We validated the findings by performing intraperitoneal injections of calcium channel blockers and microinjections of dorsal root ganglion cells with adeno-associated virus. We found that short-term sleep deprivation before and after surgery increased expression and activity of L-type calcium channels in the lumbar dorsal root ganglia, and delayed recovery from postsurgical pain. Blocking these channels reduced impact of sleep deprivation. We conclude that the increased expression and activity of L-type calcium channels is associated with the sleep deprivation-mediated prolongation of postoperative pain. L-type calcium channels are thus a potential target for management of postoperative pain.

High-Salt Diet Causes Sleep Fragmentation in Young Drosophila Through Circadian Rhythm and Dopaminergic Systems

Salt (sodium chloride) is an essential dietary requirement, but excessive consumption has long-term adverse consequences. A high-salt diet (HSD) increases the risk of chronic diseases such as cardiovascular conditions and diabetes and is also associated with poor sleep quality. Little is known, however, about the neural circuit mechanisms that mediate HSD-induced sleep changes. In this study, we sought to identify the effects of HSD on the sleep and related neural circuit mechanisms of Drosophila. Strikingly, we found that HSD causes young Drosophila to exhibit a fragmented sleep phenotype similar to that of normal aging individuals. Importantly, we further showed that HSD slightly impairs circadian rhythms and that the HSD-induced sleep changes are dependent on the circadian rhythm system. In addition, we demonstrated that HSD-induced sleep changes are dopaminergic-system dependent. Together, these results provide insight into how elevated salt in the diet can affect sleep quality.

Sleep Deprivation Modifies Noise-Induced Cochlear Injury Related to the Stress Hormone and Autophagy in Female Mice

A lack of sleep is linked with a range of inner ear diseases, including hearing loss and tinnitus. Here, we used a mouse model to investigate the effects of sleep deprivation (SD) on noise vulnerability, and explored the mechanisms that might be involved in vitro, focusing particularly corticosterone levels and autophagic flux in cells. Female BALB/c mice were divided into six groups [control, acoustic trauma (AT)-alone, 1 day (d) SD-alone, 1d SD pre-AT, 5d SD-alone, and 5d SD pre-AT]. Cochlear damage was then assessed by analyzing auditory brainstem response (ABR), and by counting outer hair cells (OHCs) and the synaptic ribbons of inner hair cells (IHCs). In addition, we measured levels of serum corticosterone and autophagy protein expression in the basilar membranes by ELISA kits, and western blotting, respectively. We found that SD-alone temporarily elevated ABR wave I amplitude, but had no permanent effect on hearing level or IHC ribbon numbers. Combined with AT, the number of synaptic ribbons in the 1d SD pre-AT group was significantly higher than that in the AT-alone group, whereas the 5d SD pre-AT group showed more severe synaptopathy, and a greater loss of OHCs after 2 weeks than the other experimental groups exposed to noise. Correspondingly, the levels of corticosterone in the AT-alone group were higher than those of the 1d SD pre-AT group, but lower than those of the 5d SD pre-AT group. The 1d SD pre-AT group showed a marked elevation in the expression of microtubule-associated protein 1 light chain 3B (LC3B), whereas the AT-alone group exhibited only a mild increase. In contrast, the levels of LC3B did not change in the 5d SD pre-AT group. Experiments with HEI-OC-1 cells and cochlear basilar membrane cultures showed that high-concentrations of dexamethasone, and the inhibition of autophagy, aggravated cellular apoptosis induced by oxidative stress. In conclusion, noise-induced synaptopathy and hair cell loss can be mitigated by preceding 1d SD, but will be aggravated by preceding 5d SD. These findings may be attributable to corticosterone levels and the extent of autophagy.

Inherited and Environmental Factors Influence Human Monocyte Heterogeneity

Blood monocytes develop in the bone marrow before being released into the peripheral circulation. The circulating monocyte pool is composed of multiple subsets, each with specialized functions. These cells are recruited to repopulate resident monocyte-derived cells in the periphery and also to sites of injury. Several extrinsic factors influence the function and quantity of monocytes in the blood. Here, we outline the impact of sex, ethnicity, age, sleep, diet, and exercise on monocyte subsets and their function, highlighting that steady state is not a single physiological condition. A clearer understanding of the relationship between these factors and the immune system may allow for improved therapeutic strategies.

Exercise reduces inflammatory cell production and cardiovascular inflammation via instruction of hematopoietic progenitor cells

A sedentary lifestyle, chronic inflammation and leukocytosis increase atherosclerosis; however, it remains unclear whether regular physical activity influences leukocyte production. Here we show that voluntary running decreases hematopoietic activity in mice. Exercise protects mice and humans with atherosclerosis from chronic leukocytosis but does not compromise emergency hematopoiesis in mice. Mechanistically, exercise diminishes leptin production in adipose tissue, augmenting quiescence-promoting hematopoietic niche factors in leptin-receptor-positive stromal bone marrow cells. Induced deletion of the leptin receptor in Prrx1-creER^T2; Lepr^fl/fl mice reveals that leptin's effect on bone marrow niche cells regulates hematopoietic stem and progenitor cell (HSPC) proliferation and leukocyte production, as well as cardiovascular inflammation and outcomes. Whereas running wheel withdrawal quickly reverses leptin levels, the impact of exercise on leukocyte production and on the HSPC epigenome and transcriptome persists for several weeks. Together, these data show that physical activity alters HSPCs via modulation of their niche, reducing hematopoietic output of inflammatory leukocytes.

Sixteen-Week Physical Activity Intervention in Subjects With Increased Cardiometabolic Risk Shifts Innate Immune Function Towards a Less Proinflammatory State

Background

Low‐grade inflammation, largely mediated by monocyte‐derived macrophages, contributes to atherosclerosis. Sedentary behavior is associated with atherosclerosis and cardiovascular diseases (CVD). We examined whether reducing sedentary behavior and improving walking time improves monocyte inflammatory phenotype in subjects with increased cardiovascular risk.

Methods and Results

Across 2 waves, 16 individuals with increased cardiovascular risk performed a 16‐week intervention study (age 64±6 years, body mass index 29.9±4.3 kg/m²), using a device with vibration feedback to promote physical activity. Before and after intervention, we objectively examined physical activity (ActivPAL), cytokine production capacity after ex vivo stimulation in peripheral blood mononuclear cells, metabolism of peripheral blood mononuclear cells, circulating cytokine concentrations, and monocyte immunophenotype. Overall, no significant increase in walking time was found (1.9±0.7 to 2.2±1.2 h/day, P=0.07). However, strong, inverse correlations were observed between the change in walking time and the change in production of interleukin (IL)‐1β, IL‐6, IL‐8, and IL‐10 after lipopolysaccharide stimulation (r_s=−0.655, −0.844, −0.672, and −0.781, respectively, all P<0.05). After intervention optimization based on feedback from wave 1, participants in wave 2 (n=8) showed an increase in walking time (2.2±0.8 to 3.0±1.3 h/day, P=0.001) and attenuated cytokine production of IL‐6, IL‐8, and IL‐10 (all P<0.05). Glycolysis (P=0.08) and maximal OXPHOS (P=0.04) of peripheral blood mononuclear cells decreased after intervention. Lower IL‐6 concentrations (P=0.06) and monocyte percentages (P<0.05), but no changes in monocyte subsets were found.

Conclusions

Successfully improving walking time shifts innate immune function towards a less proinflammatory state, characterized by a lower capacity to produce inflammatory cytokines, in individuals with increased cardiovascular risk.

Clinical Trial Registration Information

URL: http://www.trialregister.nl. Unique identifier: NTR6387.

Moderate to severe but not mild RLS is associated with greater sleep-related sympathetic autonomic activation than healthy adults without RLS

INTRODUCTION

Restless legs syndrome (RLS) patients have been found to have high rates of transitory increases in the activity of the sympathetic autonomic nervous system with increases in heart rate and blood pressure. These were identified by evaluating heart rate or blood pressure changes independent of any leg movement analyses. There has been an implicit assumption this high rate of sympathetic activations is abnormal, but there has been no direct comparison for similar measures with a healthy population free of RLS. Thus, it is not known if during sleep the rates of sympathetic nervous system activation are greater for RLS than for a healthy population. The objectives of this study were to determine if: (1) RLS patients compared to healthy controls have a greater frequency of sympathetic nervous system activation (significant heart rate increases) with a higher percentage of leg movements associated with these activations; (2) the sympathetic activation frequency and its relation to leg movements correlate significantly with RLS severity in RLS patients; and (3) there is some minimum threshold for RLS severity defining an RLS population where most (eg 85%) have abnormally high rates of sympathetic activation.

METHODS

Sleep data on 32 RLS patients and 21 matched healthy controls were obtained from a prior study. All leg movements during sleep (LMS) and periodic leg movements in sleep (PLMS) were identified following the new WASM criteria; LMS that were not PLMS were considered isolated leg movements in sleep (ILMS). All episodes with significant heart rate increases were identified following procedures established by Cassel et al., (2016, see further on for citation) ie a slope of linear regression ≥2.5 beats per minute over five consecutive heartbeats. Severity of RLS was evaluated using the International Restless Legs Study Group Scale (IRLS).

RESULTS

RLS patients had significantly more heart rate increases than controls (67.88/hr vs. 9.87/hr). RLS patients had a significantly greater percentage of both LMS and PLMS occurring with heart rate increases than controls (44% vs. 30%; 48% vs. 18%, respectively). These measures correlated significantly with IRLS and also PLMS/hr. 85% of the RLS patients with IRLS scores >22 or PLMS >50/hr had rates of sympathetic activation that were >90th percentile for the healthy controls.

CONCLUSION

This is the first paper documenting that RLS patients showed clearly increased sympathetic activation when identified independent of PLMS. This, however, occurs for more severe RLS and not milder RLS. It has been proposed that the abnormally high rate of sympathetic activation for RLS patients relates to development of adverse cardiovascular health consequences observed in some studies. Thus, these data may provide a basic standard for possible use in epidemiological studies to identify the level of RLS severity more likely to have adverse health consequences (eg, cardiovascular disease). Since two-thirds of RLS patients have mild to even intermittent disease, including all RLS is likely to miss the potential health consequences of RLS.

Guidelines for the use of flow cytometry and cell sorting in immunological studies (second edition)

These guidelines are a consensus work of a considerable number of members of the immunology and flow cytometry community. They provide the theory and key practical aspects of flow cytometry enabling immunologists to avoid the common errors that often undermine immunological data. Notably, there are comprehensive sections of all major immune cell types with helpful Tables detailing phenotypes in murine and human cells. The latest flow cytometry techniques and applications are also described, featuring examples of the data that can be generated and, importantly, how the data can be analysed. Furthermore, there are sections detailing tips, tricks and pitfalls to avoid, all written and peer-reviewed by leading experts in the field, making this an essential research companion.

Monocytes and macrophages in atherogenesis

PURPOSE OF REVIEW

Monocytes and macrophages are key players in the pathogenesis of atherosclerosis and dictate atherogenesis growth and stability. The heterogeneous nature of myeloid cells concerning their metabolic and phenotypic function is increasingly appreciated. This review summarizes the recent monocyte and macrophage literature and highlights how differing subsets contribute to atherogenesis.

RECENT FINDINGS

Monocytes are short-lived cells generated in the bone marrow and released to circulation where they can produce inflammatory cytokines and, importantly, differentiate into long-lived macrophages. In the context of cardiovascular disease, a myriad of subtypes, exist with each differentially contributing to plaque development. Herein we describe recent novel characterizations of monocyte and macrophage subtypes and summarize the recent literature on mediators of myelopoiesis.

SUMMARY

An increased understanding of monocyte and macrophage phenotype and their molecular regulators is likely to translate to the development of new therapeutic targets to either stem the growth of existing plaques or promote plaque stabilization.

Impact of Circadian Disruption on Cardiovascular Function and Disease

The circadian system, that is ubiquitous across species, generates ∼24 h rhythms in virtually all biological processes, and allows them to anticipate and adapt to the 24 h day/night cycle, thus ensuring optimal physiological function. Epidemiological studies show time-of-day variations in adverse cardiovascular (CV) events, and controlled laboratory studies demonstrate a circadian influence on key markers of CV function and risk. Furthermore, circadian misalignment, that is typically experienced by shift workers as well as by individuals who experience late eating, (social) jet lag, or circadian rhythm sleep-wake disturbances, increases CV risk factors. Therefore, understanding the mechanisms by which the circadian system regulates CV function, and which of these are affected by circadian disruption, may help to develop intervention strategies to mitigate CV risk.

Daily light and darkness onset and circadian rhythms metabolically synchronize hematopoietic stem cell differentiation and maintenance: The role of bone marrow norepinephrine, tumor necrosis factor, and melatonin cycles

Hematopoietic stem and progenitor cells (HSPCs) are essential for daily mature blood cell production, host immunity, and osteoclast-mediated bone turnover. The timing at which stem cells give rise to mature blood and immune cells while maintaining the bone marrow (BM) reservoir of undifferentiated HSPCs and how these opposite tasks are synchronized are poorly understood. Previous studies revealed that daily light onset activates norepinephrine (NE)-induced BM CXCL12 downregulation, followed by CXCR4⁺ HSPC release to the circulation. Recently, we reported that daily light onset induces transient elevations of BM NE and tumor necrosis factor (TNF), which metabolically program BM HSPC differentiation and recruitment to replenish the blood. In contrast, darkness onset induces lower elevations of BM NE and TNF, activating melatonin production, which metabolically reprograms HSPCs, increasing their short- and long-term repopulation potential, and BM maintenance. How the functions of BM-retained HSPCs are influenced by daily light and darkness cycles and their clinical potential are further discussed.

Inflammation in atherosclerotic cardiovascular disease

Atherosclerotic cardiovascular disease is a leading cause of death and morbidity globally. Over the past several years, arterial inflammation has been implicated in the pathophysiology of athero-thrombosis, substantially confirming what pathologist Rudolf Virchow had observed in the 19th century. Lipid lowering, lifestyle changes, and modification of other risk factors have reduced cardiovascular complications of athero-thrombosis, but a substantial residual risk remains. In view of the pathogenic role of inflammation in athero-thrombosis, directly targeting inflammation has emerged as an additional potential therapeutic option; and some early promising results have been suggested by the Canakinumab Anti-inflammatory Thrombosis Outcome Study (CANTOS), in which canakinumab, a fully human monoclonal antibody targeting the pro-inflammatory and pro-atherogenic cytokine interleukin 1 beta, was shown to reduce cardiovascular events.

Sleep Matters: CD4+ T Cell Memory Formation and the Central Nervous System

The mechanisms of CD4⁺ T-cell memory formation in the immune system are debated. With the well-established concept of memory formation in the central nervous system (CNS), we propose that formation of CD4⁺ T-cell memory depends on the interaction of two different cell systems handling two types of stored information. First, information about antigen (event) and challenge (context) is taken up by antigen-presenting cells, as initial storage. Second, event and context information is transferred to CD4⁺ T cells. During activation, two categories of CD4⁺ T cell develop: effector CD4⁺ T cells, carrying event and context information, enabling them to efficiently focus their response to tissues under attack; and persisting CD4⁺ T cells, providing context-independent antigen-specific memories and long-term storage. This novel hypothesis is supported by the observation that mammalian sleep can improve both CNS and CD4⁺ T-cell memory.

Hematopoietic progenitor cells as integrative hubs for adaptation to and fine-tuning of inflammation

Recent advances have highlighted the ability of hematopoietic stem and progenitor cells in the bone marrow to sense peripheral inflammation or infection and adapt through increased proliferation and skewing toward the myeloid lineage. Such adaptations can meet the increased demand for innate immune cells and can be beneficial in response to infection or myeloablation. However, the inflammation-induced adaptation of hematopoietic and myeloid progenitor cells toward enhanced myelopoiesis might also perpetuate inflammation in chronic inflammatory or cardio-metabolic diseases by generating a feed-forward loop between inflammation-adapted hematopoietic progenitor cells and the inflammatory disorder. Sustained adaptive responses of progenitor cells in the bone marrow can also contribute to trained immunity, a non-specific memory of earlier encounters that in turn facilitates the heightened response of these cells, as well as that of their progeny, to future challenges. Here we discuss the mechanisms that govern the adaptation of hematopoietic progenitor cells to inflammation and its sequelae in the pathogenesis of human disease.

Molecular Mechanisms of Cancer-Induced Sleep Disruption

Sleep is essential for health. Indeed, poor sleep is consistently linked to the development of systemic disease, including depression, metabolic syndrome, and cognitive impairments. Further evidence has accumulated suggesting the role of sleep in cancer initiation and progression (primarily breast cancer). Indeed, patients with cancer and cancer survivors frequently experience poor sleep, manifesting as insomnia, circadian misalignment, hypersomnia, somnolence syndrome, hot flushes, and nightmares. These problems are associated with a reduction in the patients' quality of life and increased mortality. Due to the heterogeneity among cancers, treatment regimens, patient populations and lifestyle factors, the etiology of cancer-induced sleep disruption is largely unknown. Here, we discuss recent advances in understanding the pathways linking cancer and the brain and how this leads to altered sleep patterns. We describe a conceptual framework where tumors disrupt normal homeostatic processes, resulting in aberrant changes in physiology and behavior that are detrimental to health. Finally, we discuss how this knowledge can be leveraged to develop novel therapeutic approaches for cancer-associated sleep disruption, with special emphasis on host-tumor interactions.

Growth Factors as Immunotherapeutic Targets in Cardiovascular Disease

Growth factors, such as CSFs (colony-stimulating factors), EGFs (epidermal growth factors), and FGFs (fibroblast growth factors), are signaling proteins that control a wide range of cellular functions. Although growth factor networks are critical for intercellular communication and tissue homeostasis, their abnormal production or regulation occurs in various pathologies. Clinical strategies that target growth factors or their receptors are used to treat a variety of conditions but have yet to be adopted for cardiovascular disease. In this review, we focus on M-CSF (macrophage-CSF), GM-CSF (granulocyte-M-CSF), IL (interleukin)-3, EGFR (epidermal growth factor receptor), and FGF21 (fibroblast growth factor 21). We first discuss the efficacy of targeting these growth factors in other disease contexts (ie, inflammatory/autoimmune diseases, cancer, or metabolic disorders) and then consider arguments for or against targeting them to treat cardiovascular disease. Visual Overview- An online visual overview is available for this article.

Cytokine Circuits in Cardiovascular Disease

Arterial inflammation is a hallmark of atherosclerosis, and appropriate management of this inflammation represents a major unmet therapeutic need for cardiovascular disease patients. Here, we review the diverse contributions of immune cells to atherosclerosis, the mechanisms of immune cell activation in this context, and the cytokine circuits that underlie disease progression. We discuss the recent application of these insights in the form of immunotherapy to treat cardiovascular disease and highlight how studies on the cardiovascular co-morbidity that arises in autoimmunity might reveal additional roles for cytokines in atherosclerosis. Currently, data point to interleukin-1β (IL-1β), tumor necrosis factor (TNF), and IL-17 as cytokines that, at least in some settings, are effective targets to reduce cardiovascular disease progression.

Off the Clock: From Circadian Disruption to Metabolic Disease

Circadian timekeeping allows appropriate temporal regulation of an organism’s internal metabolism to anticipate and respond to recurrent daily changes in the environment. Evidence from animal genetic models and from humans under circadian misalignment (such as shift work or jet lag) shows that disruption of circadian rhythms contributes to the development of obesity and metabolic disease. Inappropriate timing of food intake and high-fat feeding also lead to disruptions of the temporal coordination of metabolism and physiology and subsequently promote its pathogenesis. This review illustrates the impact of genetically or environmentally induced molecular clock disruption (at the level of the brain and peripheral tissues) and the interplay between the circadian system and metabolic processes. Here, we discuss some mechanisms responsible for diet-induced circadian desynchrony and consider the impact of nutritional cues in inter-organ communication, with a particular focus on the communication between peripheral organs and brain. Finally, we discuss the relay of environmental information by signal-dependent transcription factors to adjust the timing of gene oscillations. Collectively, a better knowledge of the mechanisms by which the circadian clock function can be compromised will lead to novel preventive and therapeutic strategies for obesity and other metabolic disorders arising from circadian desynchrony.

Central regulation of breast cancer growth and metastasis

Cancer is a systemic disease. In order to fully understand it, we must take a holistic view on how cancer interacts with its host. The brain monitors and responds to natural and aberrant signals arriving from the periphery, particularly those of metabolic or immune origin. As has been well described, a hallmark of cancer is marked disruption of metabolic and inflammatory processes. Depending on the salience and timing of these inputs, the brain responds via neural and humoral routes to alter whole-body physiology. These responses have consequences for tumor growth and metastasis, directly influencing patient quality of life and subsequent mortality. Additionally, environmental inputs such as light, diet, and stress, can promote inappropriate neural activity that benefits cancer. Here, I discuss evidence for brain-tumor interactions, with special emphasis on subcortical neuromodulator neural populations, and potential ways of harnessing this cross-talk as a novel approach for cancer treatment.

To Sleep, Perchance to Survive?

Multicellular organisms exist in a sea of microbes. Survival is enabled by an immense diversity of antimicrobial peptides (AMPs) that maintain homeostasis with the microbiota. During pathogen infection, fruit fly survival varies directly with sleep. A newly-identified fruit fly sleep-regulator is also an AMP (Toda et al. Science 2019;363:509-515). Its characterization may clarify the association between sleep and surviving infection.