Circadian rhythms of cardiovascular autonomic function: Physiology and clinical implications in neurodegenerative diseases

Active compounds: A new direction for rice value addition

The development of rice active compounds is conducive to improving the added value of rice. This paper focused on the types and effects of active compounds in rice. Furthermore, it summarized the effect of rice storage and processing technology on rice active compounds. We conclude the following: Rice contains a large number of active compounds that are beneficial to humans. At present, the research on the action mechanism of rice active compounds on the human body is not deep enough, and the ability to deeply process rice is insufficient, greatly limiting the development of the rice active compound industry. To maximize the added value of rice, it is necessary to establish a dedicated preservation and processing technology system based on the physicochemical properties of the required active compounds. Additionally, attention should be paid to the development and application of composite technologies during the development of the rice active compound industry.

Time of hemodialysis and risk of intradialytic hypotension and intradialytic hypertension in maintenance hemodialysis

Intradialytic hypotension and intradialytic hypertension are complications of hemodialysis (HD) associated with a higher risk of cardiovascular disease (CVD) and death. Blood pressure (BP) normally fluctuates in a circadian pattern, but whether the risk of intradialytic hypotension and intradialytic hypertension varies according to the time of the HD session is unknown. We analyzed two cohorts of thrice-weekly maintenance HD (N = 1838 patients/n = 64,503 sessions from the Hemodialysis [HEMO] Study, and N = 3302 patients/n = 33,590 sessions from Satellite Healthcare). Random effects logistic regression models examined the association of HD start time (at or before 9:00 a.m. [early AM], between 9:01 a.m. and 12:00 p.m. [late AM], and at or after 12:01 p.m. [PM]) with intradialytic hypotension (defined as nadir intra-HD systolic BP (SBP) < 90 mmHg if pre-HD SBP < 160 mmHg, or <100 mmHg if pre-HD SBP ≥ 160 mmHg) and intradialytic hypertension (SBP increase ≥ 10 mmHg from pre-HD to post-HD). Compared to early AM, late AM and PM were associated with an 8% (aOR 0.92, 95% CI 0.83-1.02) and a 16% (aOR 0.84, 95% CI 0.75-0.95) lower risk of intradialytic hypotension in HEMO, respectively. Conversely, compared to early AM, a monotonic higher risk of intradialytic hypertension was observed for late AM (aOR 1.23, 95% CI 1.12-1.35) and PM (aOR 1.41, 95% CI 1.27-1.56) in HEMO. These findings were consistent in Satellite. In two large cohorts of maintenance HD, we observed a monotonic lower risk of intradialytic hypotension and a monotonic higher risk of intradialytic hypertension with later dialysis start times. Whether HD treatment allocation to certain times of the day in hypotensive-prone or hypertensive-prone patients improves outcomes deserves further investigation.

Circadian aspects of mortality in hospitalized patients: A retrospective observation from a large cohort

AIM

This study aimed to describe the circadian characteristics of hospitalized mortality in order to provide nursing guidance for preventing in-hospital mortality.

DESIGN

A retrospective analysis on inpatient information was implemented.

METHODS

Harmonic Analysis of Time Series was applied to quantify the periodic structure of the frequency of the occurrence of death.

RESULTS

A total of 3300 cases were included in the present study (male, 63.4% and median age 73 years), including 1540 (46.7%) ICU patients. Incidence of overall hospitalized death exhibited a circadian pattern, presenting peaks from 07:00 to 12:00 and 15:00 to 20:00 P.M., with 21.5% and 13.1% increase above the average at those peak points, respectively. Similarly, the incidence of sudden cardiac death (SCD) showed peaks between 06:00-12:00 and 15:00-20:00, with a 34.7% and 28.0% increase above the average at peak time, respectively. The distribution of death incidence revealed no statistical difference between SCD and non-SCD (p = 0.525).

Cardiovascular Dysautonomia in Patients with Breast Cancer

Breast cancer is the most frequent malignant disease among women, being responsible for a considerable percentage of fatalities and comorbidities every year. Despite advances in early detection and therapy, evidence shows that breast cancer survivors are at increased risk of developing other chronic conditions, such as cardiovascular diseases.

Autonomic dysfunction is an emerging, but poorly understood topic that has been suggested as a risk factor for cardiovascular disease in breast cancer patients. It clinically manifests through persistently elevated heart rates and abnormal heart rate variability, even before any signs of cardiovascular dysfunction appear. Since changes in the left ventricular ejection fraction only manifest when myocardial injury has already occurred, it has been hypothesized that autonomic dysfunction can constitute an early biomarker of cardiovascular impairment in breast cancer patients.

This review focuses on the direct and indirect effects of cancer and its treatment on the autonomic nervous system in breast cancer patients. We highlight the mechanisms potentially involved in cancer and antineoplastic therapy-related autonomic imbalance and review the potential strategies to prevent and/or attenuate autonomic dysfunction.

There are gaps in the current knowledge; more research in this area is needed to identify the relevance of autonomic dysfunction and define beneficial interventions to prevent cardiovascular disease in breast cancer patients.

Diurnal dynamic range as index of dysregulation of system dynamics. A cortisol examplar using data from the Study of Midlife in the United States

We discuss the importance of including measures of dysregulated system dynamics in the operationalization of allostatic load. The concept of allostatic load, as originally proposed by McEwen and Stellar, included dysregulation not only in the resting state of physiological systems, but also in system dynamics. We describe previous work on cortisol diurnal dynamic range (peak to nadir spread) as an index of the health of the hypothalamic-pituitary-adrenal axis, with compression of dynamic range being a marker of dysregulation. In particular, we review the evidence for a) diurnal dynamic range compression in people from disadvantaged backgrounds, b) cross-sectional association of cortisol diurnal dynamic range compression with dysregulation in other systems' resting states, and c) cross-sectional association of cortisol diurnal dynamic range compression with lower scores on cognitive testing. Then, we present new data from the Study of Midlife in the United States (MIDUS) on longitudinal associations of cortisol dynamic range compression with subsequent cognitive decline and all-cause mortality. Briefly, each standard deviation decrement in cortisol diurnal dynamic range is associated with adjusted mortality hazard ratio of 1.35 (95% confidence interval: 1.19, 1.54). Among those who scored at median or lower in executive functioning at baseline and survive, each standard deviation decrement in cortisol dynamic range is associated with 1% greater decline in executive functioning over a decade (95% confidence interval: 0.4%, 2.0%). We conclude that including measures of system dynamics like diurnal dynamic range in the next generation of allostatic load measurement will likely advance understanding of the cumulative physiological burden of chronic stress and life experiences, and improve the prediction of future health consequences.

Circadian patterns of heart rate, respiratory rate and skin temperature in hospitalized COVID-19 patients

Rationale

Vital signs follow circadian patterns in both healthy volunteers and critically ill patients, which seem to be influenced by disease severity in the latter. In this study we explored the existence of circadian patterns in heart rate, respiratory rate and skin temperature of hospitalized COVID-19 patients, and aimed to explore differences in circadian rhythm amplitude during patient deterioration.

Methods

We performed a retrospective study of COVID-19 patients admitted to the general ward of a tertiary hospital between April 2020 and March 2021. Patients were continuously monitored using a wireless sensor and fingertip pulse oximeter. Data was divided into three cohorts: patients who recovered, patients who developed respiratory insufficiency and patients who died. For each cohort, a population mean cosinor model was fitted to detect rhythmicity. To assess changes in amplitude, a mixed-effect cosinor model was fitted.

Results

A total of 429 patients were monitored. Rhythmicity was observed in heartrate for the recovery cohort (p<0.001), respiratory insufficiency cohort (p<0.001 and mortality cohort (p = 0.002). Respiratory rate showed rhythmicity in the recovery cohort (p<0.001), but not in the other cohorts (p = 0.18 and p = 0.51). Skin temperature also showed rhythmicity in the recovery cohort (p<0.001), but not in the other cohorts (p = 0.22 and p = 0.12). For respiratory insufficiency, only the amplitude of heart rate circadian pattern increased slightly the day before (1.2 (99%CI 0.16–2.2, p = 0.002)). In the mortality cohort, the amplitude of heart rate decreased (-1.5 (99%CI -2.6- -0.42, p<0.001)) and respiratory rate amplitude increased (0.72 (99%CI 0.27–1.3, p = 0.002) the days before death.

Conclusion

A circadian rhythm is present in heart rate of COVID-19 patients admitted to the general ward. For respiratory rate and skin temperature, rhythmicity was only found in patients who recover, but not in patients developing respiratory insufficiency or death. We found no consistent changes in circadian rhythm amplitude accompanying patient deterioration.

Longitudinal assessment of aggression and circadian rhythms in the APPswe mouse model of Alzheimer`s disease

Agitation, which comprises verbal or physical aggression and hyperactivity, is one of the most frequent neuropsychiatric symptoms observed in patients with Alzheimer's disease (AD). It often co-occurs with dysregulated circadian rhythms. Current medications are associated with serious adverse effects, and novel therapeutics are therefore needed. Rodent models can be instrumental to provide a first signal for potential efficacy of novel drug candidates. Longitudinal data assessing the face validity of such models for AD-related agitation are largely missing. We employed telemeterized APPswe mice, a frequently used AD transgenic mouse line overexpressing the human beta-amyloid precursor protein (APP) with the Swedish KM670/671NL mutation, to study the occurrence and progression of changes in reactive aggressive behavior as well as the circadian profile of locomotor activity and body temperature. Analysis was conducted between 5 and 11 months of age, at regular 2-months intervals. The aggressivity of all mice was highest at 5 months and waned with increasing age. APPswe mice were more aggressive than WT at 5 and 7 months of age. The locomotor activity and body temperature of WT mice declined with increasing age, while that of APPswe mice remained rather constant. This genotype difference was solely evident during the active, dark phase. APPswe mice did not display a phase shift of their circadian rhythms. We conclude that the APPswe mouse line can recapitulate some of the behavioral disturbances observed in AD, including an agitation-relevant phenotype characterized by active phase hyperactivity and aggressivity. It does not recapitulate the nighttime disturbances (also characterized by hyperactivity) and the shift of circadian rhythms observed in AD patients. Therefore, the APPswe strain could be used at specific ages to model a subset of agitation-relevant behavioral problems and to test the modulatory effects of drugs.

Research Opportunities in Autonomic Neural Mechanisms of Cardiopulmonary Regulation: A Report From the National Heart, Lung, and Blood Institute and the National Institutes of Health Office of the Director Workshop

This virtual workshop was convened by the National Heart, Lung, and Blood Institute, in partnership with the Office of Strategic Coordination of the Office of the National Institutes of Health Director, and held September 2 to 3, 2020. The intent was to assemble a multidisciplinary group of experts in basic, translational, and clinical research in neuroscience and cardiopulmonary disorders to identify knowledge gaps, guide future research efforts, and foster multidisciplinary collaborations pertaining to autonomic neural mechanisms of cardiopulmonary regulation. The group critically evaluated the current state of knowledge of the roles that the autonomic nervous system plays in regulation of cardiopulmonary function in health and in pathophysiology of arrhythmias, heart failure, sleep and circadian dysfunction, and breathing disorders. Opportunities to leverage the Common Fund's SPARC (Stimulating Peripheral Activity to Relieve Conditions) program were characterized as related to nonpharmacologic neuromodulation and device-based therapies. Common themes discussed include knowledge gaps, research priorities, and approaches to develop novel predictive markers of autonomic dysfunction. Approaches to precisely target neural pathophysiological mechanisms to herald new therapies for arrhythmias, heart failure, sleep and circadian rhythm physiology, and breathing disorders were also detailed.

Compensatory ion transport buffers daily protein rhythms to regulate osmotic balance and cellular physiology

Between 6-20% of the cellular proteome is under circadian control and tunes mammalian cell function with daily environmental cycles. For cell viability, and to maintain volume within narrow limits, the daily variation in osmotic potential exerted by changes in the soluble proteome must be counterbalanced. The mechanisms and consequences of this osmotic compensation have not been investigated before. In cultured cells and in tissue we find that compensation involves electroneutral active transport of Na⁺, K⁺, and Cl^- through differential activity of SLC12A family cotransporters. In cardiomyocytes ex vivo and in vivo, compensatory ion fluxes confer daily variation in electrical activity. Perturbation of soluble protein abundance has commensurate effects on ion composition and cellular function across the circadian cycle. Thus, circadian regulation of the proteome impacts ion homeostasis with substantial consequences for the physiology of electrically active cells such as cardiomyocytes.

Sleep, neuronal hyperexcitability, inflammation and neurodegeneration: Does early chronic short sleep trigger and is it the key to overcoming Alzheimer's disease?

Evidence links neuroinflammation to Alzheimer's disease (AD); however, its exact contribution to the onset and progression of the disease is poorly understood. Symptoms of AD can be seen as the tip of an iceberg, consisting of a neuropathological build-up in the brain of extracellular amyloid-β (Aβ) plaques and intraneuronal hyperphosphorylated aggregates of Tau (pTau), which are thought to stem from an imbalance between its production and clearance resulting in loss of synaptic health and dysfunctional cortical connectivity. The glymphatic drainage system, which is particularly active during sleep, plays a key role in the clearance of proteinopathies. Poor sleep can cause hyperexcitability and promote Aβ and tau pathology leading to systemic inflammation. The early neuronal hyperexcitability of γ-aminobutyric acid (GABA)-ergic inhibitory interneurons and impaired inhibitory control of cortical pyramidal neurons lie at the crossroads of excitatory/inhibitory imbalance and inflammation. We outline, with a prospective framework, a possible vicious spiral linking early chronic short sleep, neuronal hyperexcitability, inflammation and neurodegeneration. Understanding the early predictors of AD, through an integrative approach, may hold promise for reducing attrition in the late stages of neuroprotective drug development.

Day-to-day progression of vital-sign circadian rhythms in the intensive care unit

Background

Disrupted vital-sign circadian rhythms in the intensive care unit (ICU) are associated with complications such as immune system disruption, delirium and increased patient mortality. However, the prevalence and extent of this disruption is not well understood. Tools for its detection are currently limited.

Methods

This paper evaluated and compared vital-sign circadian rhythms in systolic blood pressure, heart rate, respiratory rate and temperature. Comparisons were made between the cohort of patients who recovered from the ICU and those who did not, across three large, publicly available clinical databases. This comparison included a qualitative assessment of rhythm profiles, as well as quantitative metrics such as peak–nadir excursions and correlation to a demographically matched ‘recovered’ profile.

Results

Circadian rhythms were present at the cohort level in all vital signs throughout an ICU stay. Peak–nadir excursions and correlation to a ‘recovered’ profile were typically greater throughout an ICU stay in the cohort of patients who recovered, compared to the cohort of patients who did not.

Conclusions

These results suggest that vital-sign circadian rhythms are typically present at the cohort level throughout an ICU stay and that quantitative assessment of these rhythms may provide information of prognostic use in the ICU.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03574-w.

Light cycle phase advance as a model for jet lag reprograms the circadian rhythms of murine extraorbital lacrimal glands

PURPOSE

Jet lag causes a disruption in physiological rhythms in humans. This study aims to explore the extent to which jet lag affects the circadian rhythmicity in the lacrimal glands.

METHODS

C57BL/6J mice were subjected to a 12-h light/12-h dark (LD) cycle and an 8-h advanced LD schedule as a model for jet lag. On day 5 after the LD advance, the extraorbital lacrimal glands (ELGs) were collected at 3-h intervals during a 24-h cycle. Total mRNA was extracted from normal and advanced LD-treated ELGs and assayed using high-throughput RNA sequencing. The rhythmic transcripts were identified, analyzed, and visualized by bioinformatics techniques. Finally, (i) animal behavior; (ii) the mass, cell size, and secretion response of ELGs; and (iii) circadian migration of immune cells to ELGs were also assayed.

RESULTS

Jet lag treatment drastically altered the phase and composition of the rhythmic transcripts compared to that of normal ELGs. The key biological processes, signaling pathways, and protein-protein association networks were also dramatically altered in a spatiotemporal pattern. Furthermore, the circadian migration of neutrophils, T cells, B cells, and macrophages to the ELGs increased and shifted later by 6-h. Finally, the circadian rhythms of the ELGs with respect to mass, cell size, and secretion response were also impaired in jet lag-treated animals.

CONCLUSIONS

Jet lag impairs the circadian rhythm of the transcriptomic profile, structure, and secretion function of the lacrimal glands. This information provides novel insight into the negative effects of jet lag on ELGs.

Circadian and Sleep Dysfunctions in Neurodegenerative Disorders-An Update

Disruptions of sleep and circadian rhythms are among the most debilitating symptoms in patients with neurodegenerative diseases. Their underlying pathophysiology is multilayered and multifactorial. Recent evidence suggests that sleep and circadian disturbances may influence the neurodegenerative processes as well as be their consequence. In this perspective, we provide an update of the current understanding of sleep and circadian dysregulation in Alzheimer's, Parkinson's, and Huntington's diseases.

Circadian alterations in patients with neurodegenerative diseases: Neuropathological basis of underlying network mechanisms

Circadian organization of physiology and behavior is an important biological process that allows organisms to anticipate and prepare for daily changes and demands. Disruptions in this system precipitates a wide range of health issues. In patients with neurodegenerative diseases, alterations of circadian rhythms are among the most common and debilitating symptoms. Although a growing awareness of these symptoms has occurred during the last decade, their underlying neuropathophysiological circuitry remains poorly understood and consequently no effective therapeutic strategies are available to alleviate these health issues. Recent studies have examined the neuropathological status of the different neural components of the circuitry governing the generation of circadian rhythms in neurodegenerative diseases. In this review, we will dissect the potential contribution of dysfunctions in the different nodes of this circuitry to circadian alterations in patients with neurodegenerative diseases. A deeper understanding of these mechanisms will provide not only a better understanding of disease neuro-pathophysiology, but also hold the promise for developing effective and mechanisms-based therapies.

Structure and function of the perivascular fluid compartment and vertebral venous plexus: Illumining a novel theory on mechanisms underlying the pathogenesis of Alzheimer's, cerebral small vessel, and neurodegenerative diseases

Blood dynamically and richly supplies the cerebral tissue via microvessels invested in pia matter perforating the cerebral substance. Arteries penetrating the cerebral substance derive an investment from one or two successive layers of pia mater, luminally apposed to the pial-glial basal lamina of the microvasculature and abluminally apposed to a series of aquaporin IV-studded astrocytic end feet constituting the soi-disant glia limitans. The full investment of successive layers forms the variably continuous walls of the periarteriolar, pericapillary, and perivenular divisions of the perivascular fluid compartment. The pia matter disappears at the distal periarteriolar division of the perivascular fluid compartment. Plasma from arteriolar blood sequentially transudates into the periarteriolar division of the perivascular fluid compartment and subarachnoid cisterns in precession to trickling into the neural interstitium. Fluid from the neural interstitium successively propagates into the venules through the subarachnoid cisterns and perivenular division of the perivascular fluid compartment. Fluid fluent within the perivascular fluid compartment flows gegen the net direction of arteriovenular flow. Microvessel oscillations at the central tendency of the cerebral vasomotion generate corresponding oscillations of within the surrounding perivascular fluid compartment, interposed betwixt the abluminal surface of the vessels and internal surface of the pia mater. The precise microanatomy of this most fascinating among designable spaces has eluded the efforts of various investigators to interrogate its structure, though most authors non-consensusly concur the investing layers effectively and functionally segregate the perivascular and subarachnoid fluid compartments. Enlargement of the perivascular fluid compartment in a variety of neurological disorders, including senile dementia of the Alzheimer's type and cerebral small vessel disease, may alternately or coordinately constitute a correlative marker of disease severity and a possible cause implicated in the mechanistic pathogenesis of these conditions. Venular pressures modulating oscillatory dynamic flow within the perivascular fluid compartment may similarly contribute to the development of a variety among neurological disorders. An intimate understanding of subtle features typifying microanatomy and microphysiology of the investing structures and spaces of the cerebral microvasculature may powerfully inform mechanistic pathophysiology mediating a variety of neurovascular ischemic, neuroinfectious, neuroautoimmune, and neurodegenerative diseases.

Cardioneuroablation in the Management of Vasovagal Syncope, Sinus Node Dysfunction, and Functional Atrioventricular Block - Techniques

Cardioneuroablation is an emerging therapy to treat vasovagal syncope, functional atrioventricular block and sinus dysfunction. Currently, there are several effective approaches due to the complex modulation of autonomic nervous system. In this review, we describe techniques of this innovative therapy based on published literature and our experiences.

Impact of Circadian Blood Pressure Pattern on Silent Cerebral Small Vessel Disease: A Systematic Review and Meta-Analysis

Background

Abnormal circadian blood pressure (BP) variations during sleep, specifically the non‐dipping (<10% fall in nocturnal BP) and reverse‐dipping patterns (rise in nocturnal BP), have been associated with an increased risk of cardiovascular events and target organ damage. However, the relationship between abnormal sleep BP variations and cerebral small vessel disease markers is poorly established. This study aims to assess the association between non‐dipping and reverse‐dipping BP patterns with markers of silent cerebral small vessel disease.

Methods and Results

MEDLINE, Embase, and Cochrane Databases were searched from inception through November 2019. Studies that reported the odds ratios (ORs) for cerebral small vessel disease markers in patients with non‐dipping or reverse‐dipping BP patterns were included. Effect estimates from the individual studies were extracted and combined using the random‐effect, generic inverse variance method of DerSimonian and Laird. Twelve observational studies composed of 3497 patients were included in this analysis. The reverse‐dipping compared with normal dipping BP pattern was associated with a higher prevalence of white matter hyperintensity with a pooled adjusted OR of 2.00 (95% CI, 1.13–2.37; I²=36%). Non‐dipping BP pattern compared with normal dipping BP pattern was associated with higher prevalence of white matter hyperintensity and asymptomatic lacunar infarction, with pooled ORs of 1.38 (95% CI, 0.95–2.02; I²=52%) and 2.33 (95% CI, 1.30–4.18; I²=73%), respectively. Limiting to only studies with confounder‐adjusted analysis resulted in a pooled OR of 1.38 (95% CI, 0.95–2.02; I²=52%) for white matter hyperintensity and 1.44 (95% CI, 0.97–2.13; I²=0%) for asymptomatic lacunar infarction.

Conclusions

The non‐dipping and reverse‐dipping BP patterns are associated with neuroimaging cerebral small vessel disease markers.

A Personalized Signature and Chronotherapy-Based Platform for Improving the Efficacy of Sepsis Treatment

Sepsis remains a major therapeutic challenge and is associated with a high rate of morbidity and mortality. It is a dynamic condition in which multiple parameters change over time, rendering it difficult to overcome the various injurious responses, which worsen the prognosis in these patients. The prognosis of sepsis is associated with a disbalance of compensatory responses to infectious triggers, part of which can be deleterious. Marked inter- and intra-patient variability characterizes the mechanisms that underlie sepsis progression and determine the response to therapy. In this paper, we review some of the data on the use of chronopharmacological approaches for the treatment of patients with sepsis and discuss the role of the autonomic nervous system in the mechanisms associated with immune response and chronotherapy in these patients. We describe the implementation of an individualized platform that is based on the personalized autonomic nervous system, immune, and chronobiology-derived parameters for generating a patient-tailored therapeutic regimen. The notion of overcoming the deleterious compensatory response in a highly dynamic system in sepsis is presented to ensure an improved response to current therapies.

Selection of suitable reference genes for core clock gene expression analysis by real-time qPCR in rat ovary granulosa cells

Selection of a suitable endogenous reference gene is essential for investigating expression of clock genes Bmal1, Clock, Pers, Crys, Rev-erbα/β, and RORα/β/γ involved in the circadian system. In this study, we treated rat ovary granulosa cells with dexamethasone to synchronize circadian oscillation in vitro and determined expression levels of Bmal1 and Per2 and six candidate reference genes (Actb, Beta actin; B2m, Beta-2-microglobulin; Ppia, Cyclophilin A; Gapdh, Glyceraldehyde-3-phosphate dehydrogenase; Hprt, Hypoxanthine guanine phosphoribosyl transferase and Tbp, TATA-box-binding protein) using quantitative real-time PCR. We then employed three software programs, GeNorm, NormFinder, and BestKeeper, to analyze the expression data for the selection of the best reference gene. According to GeNorm, Tbp and B2m were assessed as the most stable reference genes; Tbp and Hprt were best by NormFinder and BestKeeper, respectively. Thus, we recommend Tbp as the most suitable reference gene for studying clock genes expression in rat ovary granulosa cells in vitro.