Circadian rhythms: influence on physiology, pharmacology, and therapeutic interventions

Genome-wide analysis of two different regions of brain reveals the molecular changes of fertility related genes in rln3a-/- mutants in male Nile tilapia (Oreochromis niloticus)

Relaxin3 (rln3) has been associated with various emotional and cognitive processes, including stress, anxiety, learning, memory, motivational behavior, and circadian rhythm. Notably, previous report revealed that Rln3a played an indispensable role in testicular development and male fertility in Nile tilapia (Oreochromis niloticus). However, the underlying molecular mechanisms remain largely unknown. We found that Rln3a is expressed exclusively in the diencephalon* (Di*) of the brain. Deficiency of Rln3a resulted in a significant increase in serum dopamine level and an upregulation of gene expression of gnrh1 and kisspeptin2. To further elucidate the role of Rln3a in fish fertility, we collected two different regions of Di* and hypothalamus (Hyp) tissues for subsequent RNA-seq analysis of both wild-type (rln3a+/+) and rln3a-/- male tilapia. Upon the transcriptomic data, 1136 and 755 differentially expressed genes (DEGs) were identified in the Di* and Hyp tissues, respectively. In Di*, the up-regulated genes were enriched in circadian rhythm, chemical carcinogenesis, while the down-regulated genes were enriched in type II diabetes mellitus, dopaminergic synapse, and other pathways. In Hyp, the up-regulated genes were enriched in circadian rhythm, pyrimidine metabolism, while the down-regulated genes were enriched in type I diabetes mellitus, autoimmune thyroid disease, and other pathways. Subsequently, the results of both qRT-PCR and FISH assays highlighted a pronounced up-regulation of core circadian rhythm genes, cry1b and per3, whereas genes such as clocka, clockb, and arntl exhibited down-regulation. Furthermore, the genes associated with dopamine biosynthesis were significantly increased in the Hyp. In summary, the mutation of rln3a in male tilapia resulted in notable changes in circadian rhythm and disease-linked signaling pathways in the Di* and Hyp. These changes might account for the fertility defects observed in rln3a-/- male mutants in tilapia.

Chrono-tailored drug delivery systems: recent advances and future directions

Circadian rhythms influence a range of biological processes within the body, with the central clock or suprachiasmatic nucleus (SCN) in the brain synchronising peripheral clocks around the body. These clocks are regulated by external cues, the most influential being the light/dark cycle, in order to synchronise with the external day. Chrono-tailored or circadian drug delivery systems (DDS) aim to optimise drug delivery by releasing drugs at specific times of day to align with circadian rhythms within the body. Although this approach is still relatively new, it has the potential to enhance drug efficacy, minimise side effects, and improve patient compliance. Chrono-tailored DDS have been explored and implemented in various conditions, including asthma, hypertension, and cancer. This review aims to introduce the biology of circadian rhythms and provide an overview of the current research on chrono-tailored DDS, with a particular focus on immunological applications and vaccination. Finally, we draw on some of the key challenges which need to be overcome for chrono-tailored DDS before they can be translated to more widespread use in clinical practice.

Ex vivo study on the human blood neutrophil circadian features and effects of alpha1-antitrypsin and lipopolysaccharide

AIMS

Neutrophils perform various functions in a circadian-dependent manner; therefore, we investigated here whether the effect of alpha1-antitrypsin (AAT), used as augmentation therapy, is dependent on the neutrophil circadian clock. AAT is a vital regulator of neutrophil functions, and its qualitative and/or quantitative defects have significant implications for the development of respiratory diseases.

METHODS

Whole blood from 12 healthy women [age years, mean (SD) 29.92 (5.48) was collected twice daily, 8 h apart, and incubated for 30 min at 37 °C alone or with additions of 2 mg/ml AAT (Respreeza) and/or 5 μg/ml lipopolysaccharide (LPS) from Escherichia coli. Neutrophils were then isolated to examine gene expression, migration and phagocytosis.

RESULTS

The expression of CD14, CD16, CXCR2 and SELL (encoding CD62L) genes was significantly higher while CDKN1A lower in the afternoon than in the morning neutrophils from untreated blood. Neutrophils isolated in the afternoon had higher migratory and phagocytic activity. Morning neutrophils isolated from AAT-pretreated blood showed higher expression of CXCR2 and SELL than those from untreated morning blood. Pretreatment of blood with AAT enhanced migratory properties of morning but not afternoon neutrophils. Of all genes analysed, only CXCL8 expression was strongly upregulated in morning and afternoon neutrophils isolated from LPS-pretreated blood, whereas CXCR2 expression was downregulated in afternoon neutrophils. The addition of AAT did not reverse the effects of LPS.

SIGNIFICANCE

The circadian clock of myeloid cells may affect the effectiveness of various therapies, including AAT therapy used to treat patients with AAT deficiency, and needs further investigation.

Circadian time-dependent effects of experimental colitis on theophylline disposition and toxicity

BACKGROUND AND PURPOSE

Drug disposition undergoes significant alteration in patients with inflammatory bowel disease (IBD), yet circadian time-dependency of these changes remains largely unexplored. In this study, we aimed to determine the temporal effects of experimental colitis on drug disposition and toxicity.

EXPERIMENTAL APPROACH

RNA-sequencing was used to screen genes relevant to colitis induced by dextran sodium sulfate in mice. Liver microsomes and pharmacokinetic analysis were used to analyze the activity of key enzymes. Dual luciferase assays and chromatin immunoprecipitation (ChIP) were employed to elucidate regulatory mechanisms.

KEY RESULTS

RNA sequencing analysis revealed that colitis markedly influenced expression of cytochrome P450 (CYP) enzymes. Specifically, a substantial down-regulation of CYP1A2 and CYP2E1 was observed in livers of mice with colitis at Zeitgeber Time 8 (ZT8), with no significant changes detected at ZT20. At ZT8, the altered expression corresponded to diminished metabolism and enhanced incidence of hepato-cardiac toxicity of theophylline, a substrate specifically metabolized by these enzymes. A combination of assays, integrating liver-specific Bmal1 knockout and targeted activation of BMAL1 showed that dysregulation in CYP1A2 and CYP2E1 during colitis was attributable to perturbed BMAL1 functionality. Luciferase reporter and ChIP assays collectively substantiated the role of BMAL1 in regulating Cyp1a2 and Cyp2e1 transcription through its binding affinity to E-box-like sites.

CONCLUSION AND IMPLICATION

Our findings establish a strong link between colitis and chronopharmacology, shedding light on how IBD affects drug disposition and toxicity over time. This research provides a theoretical foundation for optimizing drug dosage in patients with IBD.

Timing Matters: Time of Day Impacts the Ergogenic Effects of Caffeine-A Narrative Review

Caffeine has attracted significant attention from researchers in the sports field due to its well-documented ergogenic effects across various athletic disciplines. As research on caffeine continues to progress, there has been a growing emphasis on evaluating caffeine dosage and administration methods. However, investigations into the optimal timing of caffeine intake remain limited. Therefore, this narrative review aimed to assess the ergogenic effects of caffeine administration at different times during the morning (06:00 to 10:00) and evening (16:00 to 21:00). The review findings suggest that circadian rhythms play a substantial role in influencing sports performance, potentially contributing to a decline in morning performance. Caffeine administration has demonstrated effectiveness in mitigating this phenomenon, resulting in ergogenic effects and performance enhancement, even comparable to nighttime levels. While the specific mechanisms by which caffeine regulates circadian rhythms and influences sports performance remain unclear, this review also explores the mechanisms underlying caffeine's ergogenic effects, including the adenosine receptor blockade, increased muscle calcium release, and modulation of catecholamines. Additionally, the narrative review underscores caffeine's indirect impact on circadian rhythms by enhancing responsiveness to light-induced phase shifts. Although the precise mechanisms through which caffeine improves morning performance declines via circadian rhythm regulation necessitate further investigations, it is noteworthy that the timing of caffeine administration significantly affects its ergogenic effects during exercise. This emphasizes the importance of considering caffeine intake timing in future research endeavors to optimize its ergogenic potential and elucidate its mechanisms.

Brain-muscle communication prevents muscle aging by maintaining daily physiology

A molecular clock network is crucial for daily physiology and maintaining organismal health. We examined the interactions and importance of intratissue clock networks in muscle tissue maintenance. In arrhythmic mice showing premature aging, we created a basic clock module involving a central and a peripheral (muscle) clock. Reconstituting the brain-muscle clock network is sufficient to preserve fundamental daily homeostatic functions and prevent premature muscle aging. However, achieving whole muscle physiology requires contributions from other peripheral clocks. Mechanistically, the muscle peripheral clock acts as a gatekeeper, selectively suppressing detrimental signals from the central clock while integrating important muscle homeostatic functions. Our research reveals the interplay between the central and peripheral clocks in daily muscle function and underscores the impact of eating patterns on these interactions.

Immunotherapy time of infusion impacts survival in head and neck cancer: A propensity score matched analysis

The adaptive immune response is physiologically regulated by the circadian rhythm. Data in lung and melanoma malignancies suggests immunotherapy infusions earlier in the day may be associated with improved response; however, the optimal time of administration for patients with head and neck squamous cell carcinoma (HNSCC) is not known. We aimed to evaluate the association of immunotherapy infusion time with overall survival (OS) and progression free survival (PFS) in patients with HNSCC in an Institutional Review Board-approved, retrospective cohort study. 113 patients met study inclusion criteria and 98 patients were included in a propensity score-matched cohort. In the full unmatched cohort (N = 113), each additional 20 % of infusions received after 1500 h conferred an OS hazard ratio (HR) of 1.35 (95 % C.I.1.2-1.6; p-value = 0.0003) and a PFS HR of 1.34 (95 % C.I.1.2-1.6; p-value < 0.0001). A propensity score-matched analysis of patients who did or did not receive ≥20 % of infusions after 1500 h showed that those who were administered ≥20 % of infusions after 1500 h trended towards a shorter OS (HR = 1.35; p-value = 0.26) and a shorter PFS (HR = 1.57, 95 % C.I. 1.02-2.42, p-value = 0.04). Each additional 20 % of infusions received after 1500 h remained robust in the matched cohort multivariable analysis and was associated with shorter OS (adjusted HR = 1.4 (95 % C.I.1.2-1.8), p-value < 0.001). Patients with advanced HNSCC who received more of their infusions in the afternoon were associated with shorter OS and PFS and scheduling immunotherapy infusions earlier in the day may be warranted.

Circadian Rhythms of the Blood-Brain Barrier and Drug Delivery

The blood-brain barrier (BBB) is a critical interface separating the central nervous system from the peripheral circulation, ensuring brain homeostasis and function. Recent research has unveiled a profound connection between the BBB and circadian rhythms, the endogenous oscillations synchronizing biological processes with the 24-hour light-dark cycle. This review explores the significance of circadian rhythms in the context of BBB functions, with an emphasis on substrate passage through the BBB. Our discussion includes efflux transporters and the molecular timing mechanisms that regulate their activities. A significant focus of this review is the potential implications of chronotherapy, leveraging our knowledge of circadian rhythms for improving drug delivery to the brain. Understanding the temporal changes in BBB can lead to optimized timing of drug administration, to enhance therapeutic efficacy for neurological disorders while reducing side effects. By elucidating the interplay between circadian rhythms and drug transport across the BBB, this review offers insights into innovative therapeutic interventions.

Programmable intratumoral drug delivery to breast cancer using wireless bioelectronic device with electrochemical actuation

OBJECTIVE

Breast cancer is a global health concern that demands attention. In our contribution to addressing this disease, our study focuses on investigating a wireless micro-device for intratumoral drug delivery, utilizing electrochemical actuation. Microdevices have emerged as a promising approach in this field due to their ability to enable controlled injections in various applications.

METHODS

Our study is conducted within a computational framework, employing models that simulate the behavior of the microdevice and drug discharge based on the principles of the ideal gas law. Furthermore, the distribution of the drug within the tissue is simulated, considering both diffusion and convection mechanisms. To predict the therapeutic response, a pharmacodynamic model is utilized, considering the chemotherapeutic effects and cell proliferation.

RESULTS

The findings demonstrate that an effective current of 3 mA, along with an initial gas volume equal to the drug volume in the microdevice, optimizes drug delivery. Microdevices with multiple injection capabilities exhibit enhanced therapeutic efficacy, effectively suppressing cell proliferation. Additionally, tumors with lower microvascular density experience higher drug concentrations in the extracellular space, resulting in significant cell death in hypoxic regions.

CONCLUSIONS

Achieving an efficient therapeutic response involves considering both the characteristics of the tumor microenvironment and the frequency of injections within a specific time frame.

Nighttime administration of antihypertensive medication: a review of chronotherapy in hypertension

Hypertension remains a global health concern because of suboptimal blood pressure control despite advancements in antihypertensive treatments. Chronotherapy, defined as evening or bedtime administration of medication based on biological rhythms, is emerging as a potential strategy to improve blood pressure control and treatment outcomes. Clinical trials have investigated the potential effects of nighttime administration of antihypertensive medication in the improvement of 24 hours blood pressure control and reduction of cardiovascular risk. Implementing chronotherapy in clinical practice could have significant implications in enhancing blood pressure control and improving clinical outcomes in patients with hypertension, particularly those with resistant hypertension. However, recent trials have reported contradictory results, causing confusion in real-world practice. Herein we review, analyze, and critique the current evidence and propose suggestions regarding the clinical application and future directions of chronotherapy.

Circadian Rhythms, Chrononutrition, Physical Training, and Redox Homeostasis-Molecular Mechanisms in Human Health

A multitude of physiological processes, human behavioral patterns, and social interactions are intricately governed by the complex interplay between external circumstances and endogenous circadian rhythms. This multidimensional regulatory framework is susceptible to disruptions, and in contemporary society, there is a prevalent occurrence of misalignments between the circadian system and environmental cues, a phenomenon frequently associated with adverse health consequences. The onset of most prevalent current chronic diseases is intimately connected with alterations in human lifestyle practices under various facets, including the following: reduced physical activity, the exposure to artificial light, also acknowledged as light pollution, sedentary behavior coupled with consuming energy-dense nutriments, irregular eating frameworks, disruptions in sleep patterns (inadequate quality and duration), engagement in shift work, and the phenomenon known as social jetlag. The rapid evolution of contemporary life and domestic routines has significantly outpaced the rate of genetic adaptation. Consequently, the underlying circadian rhythms are exposed to multiple shifts, thereby elevating the susceptibility to disease predisposition. This comprehensive review endeavors to synthesize existing empirical evidence that substantiates the conceptual integration of the circadian clock, biochemical molecular homeostasis, oxidative stress, and the stimuli imparted by physical exercise, sleep, and nutrition.

The Influence of Weather Conditions on the Diurnal Variation in Range of Motion in Older Adults with Knee Osteoarthritis

(1) Background: This study investigated the relationship between weather conditions, diurnal patterns, and total knee range of motion (ROM), as well as the severity of symptoms (pain and stiffness) in older adults with knee osteoarthritis. (2) Methods: An exploratory longitudinal study was conducted on 28 older adults with knee osteoarthritis (mean age 71.86 ± 4.49 years; 46.4% men, 53.6% women). We used as assessment tools the Visual Analog Scales (VAS) for self-reported local knee pain and stiffness, and goniometry for ROM. Measurements were taken twice, six months apart, in winter and summer, in the morning and evening of each selected day. Recorded weather factors comprised temperature, relative humidity, barometric pressure, and maximum wind speed. (3) Results: The study revealed significant effects of season and time of day on pain and stiffness, respectively (p < 0.001). Additionally, a significant interaction between season and time influenced total knee ROM (p < 0.001). Moreover, there was a statistically significant relationship between time and total knee ROM (p < 0.001). (4) Conclusions: This research underscores the complex link between seasonal fluctuations and daily variations in some symptomatic and functional aspects of knee osteoarthritis in older adults.

Abrupt Photoperiod Changes Differentially Modulate Hepatic Antioxidant Response in Healthy and Obese Rats: Effects of Grape Seed Proanthocyanidin Extract (GSPE)

Disruptions of the light/dark cycle and unhealthy diets can promote misalignment of biological rhythms and metabolic alterations, ultimately leading to an oxidative stress condition. Grape seed proanthocyanidin extract (GSPE), which possesses antioxidant properties, has demonstrated its beneficial effects in metabolic-associated diseases and its potential role in modulating circadian disruptions. Therefore, this study aimed to assess the impact of GSPE administration on the liver oxidant system of healthy and diet-induced obese rats undergoing a sudden photoperiod shift. To this end, forty-eight photoperiod-sensitive Fischer 344/IcoCrl rats were fed either a standard (STD) or a cafeteria diet (CAF) for 6 weeks. A week before euthanizing, rats were abruptly transferred from a standard photoperiod of 12 h of light/day (L12) to either a short (6 h light/day, L6) or a long photoperiod (18 h light/day, L18) while receiving a daily oral dose of vehicle (VH) or GSPE (25 mg/kg). Alterations in body weight gain, serum and liver biochemical parameters, antioxidant gene and protein expression, and antioxidant metabolites were observed. Interestingly, GSPE partially ameliorated these effects by reducing the oxidative stress status in L6 through an increase in GPx1 expression and in hepatic antioxidant metabolites and in L18 by increasing the NRF2/KEAP1/ARE pathway, thereby showing potential in the treatment of circadian-related disorders by increasing the hepatic antioxidant response in a photoperiod-dependent manner.

Pharmacokinetic Model-Based Control across the Blood-Brain Barrier for Circadian Entrainment

The ability to shift circadian phase in vivo has the potential to offer substantial health benefits. However, the blood-brain barrier prevents the absorption of the majority of large and many small molecules, posing a challenge to neurological pharmaceutical development. Motivated by the presence of the circadian molecule KL001, which is capable of causing phase shifts in a circadian oscillator, we investigated the pharmacokinetics of different neurological pharmaceuticals on the dynamics of circadian phase. Specifically, we developed and validated five different transport models that describe drug concentration profiles of a circadian pharmaceutical at the brain level under oral administration and designed a nonlinear model predictive control (MPC)-based framework for phase resetting. Performance of the novel control algorithm based on the identified pharmacokinetic models was demonstrated through simulations of real-world misalignment scenarios due to jet lag. The time to achieve a complete phase reset for 11-h phase delay ranged between 48 and 72 h, while a 5-h phase advance was compensated in 30 to 60 h. This approach provides mechanistic insight into the underlying structure of the circadian oscillatory system and thus leads to a better understanding of the feasibility of therapeutic manipulations of the system.

The Influence of Light Wavelength on Human HPA Axis Rhythms: A Systematic Review

Environmental light entrains many physiological and behavioural processes to the 24 h solar cycle. Such light-driven circadian rhythms are centrally controlled by the suprachiasmatic nucleus (SCN), which receives information from the short-wavelength-sensitive intrinsically photosensitive retinal ganglion cells. The SCN synchronizes local clocks throughout the body affecting sleep/wake routines and the secretion of neuroendocrine-linked hormones such as melatonin from the pineal gland and cortisol via the hypothalamic pituitary adrenal (HPA) axis. Although the effects of light parameters on melatonin have been recently reviewed, whether the experimental variation of the spectral power distribution and intensity of light can induce changes in cortisol rhythms remains unclear. Thus, this systematic review evaluated the effects of daytime exposure to lights of different spectral wavelength characteristics and luminance intensity on the cortisol levels in healthy individuals. A search of the PubMed, Web of Science, EMBASE, CINAHL, Medline, PsycINFO and Cochrane Library databases on 19 June 2023 identified 3418 articles, of which 12 studies (profiling 337 participants) met the inclusion and risk of bias criteria. An analysis of the literature indicated that exposure to bright lights of any colour during the late night or early morning can induce significant increases in cortisol secretion relative to time-matched dim light comparison conditions. Furthermore, exposure to bright lights with stronger short-wavelength (blue/green) components in the early morning typically induced greater increases in cortisol relative to lights with stronger long-wavelength (red) components. Thus, the circadian regulation of cortisol is sensitive to the wavelength composition of environmental lighting, in line with the more commonly studied melatonin. As such, wavelength characteristics should be optimized and reported in light intervention studies (particularly for the investigation of cortisol-associated disorders and HPA axis function), and exposure to short-wavelength light during sensitive periods should be carefully considered in constructed environments (e.g., bedroom and classroom lighting and device screens).

New Insights into Photobiomodulation of the Vaginal Microbiome-A Critical Review

The development of new technologies such as sequencing has greatly enhanced our understanding of the human microbiome. The interactions between the human microbiome and the development of several diseases have been the subject of recent research. In-depth knowledge about the vaginal microbiome (VMB) has shown that dysbiosis is closely related to the development of gynecologic and obstetric disorders. To date, the progress in treating or modulating the VMB has lagged far behind research efforts. Photobiomodulation (PBM) uses low levels of light, usually red or near-infrared, to treat a diversity of conditions. Several studies have demonstrated that PBM can control the microbiome and improve the activity of the immune system. In recent years, increasing attention has been paid to the microbiome, mostly to the gut microbiome and its connections with many diseases, such as metabolic disorders, obesity, cardiovascular disorders, autoimmunity, and neurological disorders. The applicability of PBM therapeutics to treat gut dysbiosis has been studied, with promising results. The possible cellular and molecular effects of PBM on the vaginal microbiome constitute a theoretical and promising field that is starting to take its first steps. In this review, we will discuss the potential mechanisms and effects of photobiomodulation in the VMB.

Biological rhythms and epilepsy treatment

Approximately one-third of patients with epilepsy are drug-refractory, necessitating novel treatment approaches. Chronopharmacology, which adjusts pharmacological treatment to physiological variations in seizure susceptibility and drug responsiveness, offers a promising strategy to enhance efficacy and tolerance. This narrative review provides an overview of the biological foundations for rhythms in seizure activity, clinical implications of seizure patterns through case reports, and the potential of chronopharmacological strategies to improve treatment. Biological rhythms, including circadian and infradian rhythms, play an important role in epilepsy. Understanding seizure patterns may help individualize treatment decisions and optimize therapeutic outcomes. Altering drug concentrations based on seizure risk periods, adjusting administration times, and exploring hormone therapy are potential strategies. Large-scale randomized controlled trials are needed to evaluate the efficacy and safety of differential and intermittent treatment approaches. By tailoring treatment to individual seizure patterns and pharmacological properties, chronopharmacology offers a personalized approach to improve outcomes in patients with epilepsy.

Understanding the role of chronopharmacology for drug optimization: what do we know?

INTRODUCTION

Circadian rhythm influences the pharmacokinetics and pharmacodynamics of a number of drugs and affects their therapeutic efficacy and toxicity depending on the time of day they are administered. Chronopharmacology is a method for incorporating knowledge about circadian rhythm into pharmacotherapy. Chronotherapy, which is the clinical application of chronopharmacology, is particularly relevant when the risk and/or severity of symptoms of a disease change in a predictable manner over time. Chronotherapy has potential benefits in the treatment of many diseases.

AREAS COVERED

Although a considerable amount of knowledge about chronopharmacology and chronotherapy has been accumulated, its therapeutic application in clinical practice remains limited in terms of therapy optimization. Resolution of these issues will improve our ability to deliver adequate drug treatment.

EXPERT OPINION

We propose four approaches for promoting chronotherapy-based drug treatment in clinical practice: targeting drug development and regulatory authorities; education about chronotherapy; drug information for both health professionals and consumers; and a chronotherapy network.

Effect of Various Dosing Schedules on the Pharmacokinetics of Oral Semaglutide: A Randomised Trial in Healthy Subjects

BACKGROUND

Prescribing information instructs taking oral semaglutide (a glucagon-like peptide-1 analogue) in the fasting state, followed by a post-dose fasting period of ≥ 30 min. This trial compared the recommended dosing schedule with alternative schedules.

METHODS

This was a randomised, single-centre, multiple-dose, open-label, five-armed, parallel-group trial in healthy subjects who received once-daily oral semaglutide (3 mg for 5 days followed by 7 mg for 5 days). Subjects (n = 156) were randomised to five dosing schedules: 2-, 4-, or 6-h pre-dose fast followed by a 30-min post-dose fast (treatment arms: 2 h-30 min, 4-30 min, 6 h-30 min); 2-h pre-dose fast followed by an overnight post-dose fast (treatment arm: 2 h-night); or overnight pre-dose fast followed by a 30-min post-dose fast (reference arm: night-30 min). Semaglutide plasma concentration was measured regularly until 24 h after the 10th dose. Endpoints included area under the semaglutide plasma concentration-time curve during a 24-h interval after the 10th dose (AUC_0-24h) (primary endpoint) and maximum observed semaglutide plasma concentration after the 10th dose (C_max) (secondary endpoint).

RESULTS

Compared with an overnight pre-dose fast (reference arm: night-30 min), shorter pre-dose fasting times in the 2 h-night, 2 h-30 min, 4 h-30 min, and 6 h-30 min treatment arms resulted in significantly lower semaglutide AUC_0-24h and C_max after the 10th dose (estimated treatment ratio ranges: 0.12-0.43 and 0.11-0.44, respectively; p < 0.0001 for all comparisons). Semaglutide AUC_0-24h and C_max after the 10th dose were similar for the 2 h-30 min and 2 h-night treatment arms.

CONCLUSION

This trial supports dosing oral semaglutide in accordance with prescribing information, which requires dosing in the fasting state.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT04513704); registered August 14, 2020.

Chronotherapy in Glioblastoma: state of the art and future perspectives

Circadian rhythms regulate various processes in the human body, including drug metabolism. Chronotherapy optimizes treatment timing based on the circadian rhythm of the individual patient, such that the treatment efficacy is maximized, and adverse effects are minimized. It has been explored in different cancers with varying conclusions. Glioblastoma multiforme (GBM) is the most aggressive type of brain tumour with a very dismal prognosis. In recent years, there has been very little success in designing successful therapies to fight this disease. Chronotherapy offers the opportunity to leverage existing treatments to extend patient survival and to increase their quality of life. Here, we discuss recent advances in using chronotherapy regimens in the treatment of GMB, such as radiotherapy, temozolomide (TMZ) and bortezomib, as well as discuss novel treatments with drugs of short half-life or circadian phase specific activity, and examine the therapeutic potential of new approaches that target elements of the core circadian clock.

TimeTeller for timing health: The potential of circadian medicine to improve performance, prevent disease and optimize treatment

Circadian medicine, the study of the effects of time on health and disease has seen an uprising in recent years as a means to enhance health and performance, and optimize treatment timing. Our endogenous time generating system -the circadian clock- regulates behavioural, physiological and cellular processes. Disruptions of the clock, via external factors like shift work or jet lag, or internal perturbations such as genetic alterations, are linked to an increased risk of various diseases like obesity, diabetes, cardiovascular diseases and cancer. By aligning an individual's circadian clock with optimal times for performing daily routines, physical and mental performance, and also the effectiveness of certain therapies can be improved. Despite the benefits of circadian medicine, the lack of non-invasive tools for characterizing the clock limits the potential of the field. TimeTeller is a non-invasive molecular/digital tool for the characterization of circadian rhythms and prediction of daily routines, including treatment timing, to unlock the potential of circadian medicine and implementing it in various settings. Given the multiple known and potentially yet unknown dependent health factors of individual circadian rhythms, the utility of this emerging biomarker is best exploited in data driven, personalized medicine use cases, using health information across lifestyle, care, and research settings.

Circadian rhythm of plasminogen activator inhibitor-1 and cardiovascular complications in type 2 diabetes

Cardiovascular complications are a common death cause in type 2 diabetes patients, as they are often combined. Plasminogen-activator Inhibitor 1 (PAI-1) participates in the development and progression of cardiovascular complications in diabetes. Insulin resistance increases PAI-1 production, and high PAI-1 levels lead to an environment conducive to thrombosis and earlier and more severe vascular disease. Current evidence also suggests that PAI-1 has a rhythmic profile of circadian fluctuations and acrophase in the morning within a single day, which might explain the high morning incidence of cardiovascular events. Thus, PAI-1 is a possible drug target. Although several PAI-1 inhibitors have been developed, none have yet been allowed for clinical use. Research on rhythm has also led to the concept of "chronotherapy", a rhythm-based drug regimen expected to improve the treatment of cardiovascular complications in diabetic patients. Herein, we searched several databases and reviewed relevant articles to describe the circadian rhythm characteristics and endogenous molecular mechanisms of PAI-1, its relationship with insulin resistance, the causes of cardiovascular complications caused by PAI-1, and the current development of PAI-1 inhibitors. We also summarized the possibility of using the circadian rhythm of PAI-1 to treat cardiovascular complications in diabetic patients.

Intertwining Neuropathogenic Impacts of Aberrant Circadian Rhythm and Impaired Neuroregenerative Plasticity in Huntington’s Disease: Neurotherapeutic Significance of Chemogenetics

Huntington’s disease (HD) is a progressive neurodegenerative disorder characterized by abnormal progressive involuntary movements, cognitive deficits, sleep disturbances, and psychiatric symptoms. The onset and progression of the clinical symptoms have been linked to impaired adult neurogenesis in the brains of subjects with HD, due to the reduced neurogenic potential of neural stem cells (NSCs). Among various pathogenic determinants, an altered clock pathway appears to induce the dysregulation of neurogenesis in neurodegenerative disorders. Notably, gamma-aminobutyric acid (GABA)-ergic neurons that express the vasoactive intestinal peptide (VIP) in the brain play a key role in the regulation of circadian rhythm and neuroplasticity. While an abnormal clock gene pathway has been associated with the inactivation of GABAergic VIP neurons, recent studies suggest the activation of this neuronal population in the brain positively contributes to neuroplasticity. Thus, the activation of GABAergic VIP neurons in the brain might help rectify the irregular circadian rhythm in HD. Chemogenetics refers to the incorporation of genetically engineered receptors or ion channels into a specific cell population followed by its activation using desired chemical ligands. The recent advancement of chemogenetic-based approaches represents a potential scientific tool to rectify the aberrant circadian clock pathways. Considering the facts, the defects in the circadian rhythm can be rectified by the activation of VIP-expressing GABAergic neurons using chemogenetics approaches. Thus, the chemogenetic-based rectification of an abnormal circadian rhythm may facilitate the neurogenic potentials of NSCs to restore the neuroregenerative plasticity in HD. Eventually, the increased neurogenesis in the brain can be expected to mitigate neuronal loss and functional deficits.

The Diurnal Blood Metabolome and Effects of Vitamin D Supplementation: A Randomised Crossover Trial in Postmenopausal Women

A way to maintain an adequate vitamin D status is through supplementation. Demonstration of blood-metabolome rhythmicity of vitamin D3 post-dosing effects is lacking in the pharmaco-metabonomics area. Thus, the overall aim of this study was to investigate the diurnal changes in the blood metabolome and how these are affected by vitamin D3 supplementation. The study was conducted as a crossover study, and the treatment included 200 µg (8000 IU) of vitamin D3 as compared with placebo with a washout period of at least 10 days. The participants were postmenopausal women aged 60−80 years (N = 29) with vitamin D insufficiency (serum 25-hydroxyvitamin D < 50 nmol/L) but otherwise healthy. During the intervention day, blood samples were taken at 0 h, 2 h, 4 h, 6 h, 8 h, 10 h, 12 h, and 24 h, and plasma was analysed by proton nuclear magnetic resonance (NMR) spectroscopy as a metabolomics approach. In general, diurnal effects were identified for the majority of the 20 quantified metabolites, and hierarchical cluster analysis revealed a change in the overall plasma metabolome around 12 AM (6 h after intervention), suggesting that the diurnal rhythm is reflected in two diurnal plasma metabolomes; a morning metabolome (8−12 AM) and an afternoon/evening metabolome (2−8 PM). Overall, the effect of vitamin D supplementation on the blood metabolome was minor, with no effect on the diurnal rhythm. However, a significant effect of the vitamin D supplementation on plasma acetone levels was identified. Collectively, our findings reveal an influence of diurnal rhythm on the plasma metabolome, while vitamin D supplementation appears to have minor influence on fluctuations in the plasma metabolome.

[Chronopharmacology : The right timing can be crucial]

BACKGROUND

Chronopharmacology takes into account, among other things, the circadian rhythm, a recurring, daily rhythm of biological functions that is significantly influenced by the day-night rhythm. Daily rhythm, diseases, and therapies influence each other: the circadian rhythm, among other factors, could influence the effect of pharmacological and nonpharmacological therapies, especially in urological oncology.

AIM

This article focuses on the question of the optimal time for therapeutic interventions and considers relevant basics of chronobiological principles depending on possible biomarkers that could be targets of a future therapeutic approach.

RESULTS

With chronomodulated chemotherapy, cancer therapies are not only more tolerable, but also more effective. Effects and side effects of an active substance can change according to the circadian rhythm. Due to the introduction of particularly targeted, oral tumor therapies, a daily application would be organizationally possible, but further clinical studies are necessary for this. The internal clock could play an unexpected role, especially in hormone-dependent prostate cancer: the amount of the circadian factor Cry1 not only seems to increase in the advanced stage, but is also closely associated with a poorer prognosis. Epidemiological studies also show a connection between hormone-dependent tumors and the disruption of the rhythmic release of melatonin. Melatonin appears to be able to improve therapy as an adjunct to cancer therapy in some urological tumor entities.

Time of day as a critical variable in biology

BACKGROUND

Circadian rhythms are important for all aspects of biology; virtually every aspect of biological function varies according to time of day. Although this is well known, variation across the day is also often ignored in the design and reporting of research. For this review, we analyzed the top 50 cited papers across 10 major domains of the biological sciences in the calendar year 2015. We repeated this analysis for the year 2019, hypothesizing that the awarding of a Nobel Prize in 2017 for achievements in the field of circadian biology would highlight the importance of circadian rhythms for scientists across many disciplines, and improve time-of-day reporting.

RESULTS

Our analyses of these 1000 empirical papers, however, revealed that most failed to include sufficient temporal details when describing experimental methods and that few systematic differences in time-of-day reporting existed between 2015 and 2019. Overall, only 6.1% of reports included time-of-day information about experimental measures and manipulations sufficient to permit replication.

CONCLUSIONS

Circadian rhythms are a defining feature of biological systems, and knowing when in the circadian day these systems are evaluated is fundamentally important information. Failing to account for time of day hampers reproducibility across laboratories, complicates interpretation of results, and reduces the value of data based predominantly on nocturnal animals when extrapolating to diurnal humans.

What's wrong with my experiment?: The impact of hidden variables on neuropsychopharmacology research

The field of neuropsychopharmacology relies on behavioral assays to quantify behavioral processes related to mental illness and substance use disorders. Although these assays have been highly informative, sometimes laboratories have unpublished datasets from experiments that "didn't work". Often this is because expected outcomes were not observed in positive or negative control groups. While this can be due to experimenter error, an important alternative is that under-appreciated environmental factors can have a major impact on results. "Hidden variables" such as circadian cycles, husbandry, and social environments are often omitted in methods sections, even though there is a strong body of literature documenting their impact on physiological and behavioral outcomes. Applying this knowledge in a more critical manner could provide behavioral neuroscientists with tools to develop better testing methods, improve the external validity of behavioral techniques, and make better comparisons of experimental data across institutions. Here we review the potential impact of "hidden variables" that are commonly overlooked such as light-dark cycles, transport stress, cage ventilation, and social housing structure. While some of these conditions may not be under direct control of investigators, it does not diminish the potential impact of these variables on experimental results. We provide recommendations to investigators on which variables to report in publications and how to address "hidden variables" that impact their experimental results.

Perturbation of Circadian Rhythm Is Associated with Increased Prevalence of Chronic Kidney Disease: Results of the Korean Nationwide Population-Based Survey

Disturbances in circadian rhythms cause several health problems, such as psychosis, metabolic syndrome, and cancer; however, their effect on kidney disease remains unclear. This study aimed to evaluate the association between chronic kidney disease (CKD) and sleep disturbance in a Korean adult population. A total of 17,408 participants who completed the National Health and Nutrition Examination Survey from 2016 to 2018 were assessed for their sleep patterns and renal function. CKD was defined as an estimated glomerular filtration rate ≤ 60 mL/min/1.73 m² or a positive dipstick urinalysis. Sleep onset time and sleep duration showed significant differences between the control and CKD groups (p < 0.001). After adjusting for the covariates, sleep onset time rather than sleep duration was independently associated with incidence of CKD, and this association was more significant in people who were older, in women, and in those with low body mass index and no comorbidities. When comparing the prevalence of newly diagnosed CKD according to sleep onset time in a population with no CKD risk factors or no history of CKD, the early bedtime group showed an independent association with incidence of new CKD (odds ratio (OR), 1.535; 95% confidence interval (CI), 1.011−2.330) even after adjusting for covariates. Impaired circadian rhythm along with sleep disturbance could be associated with CKD development; therefore, sleep disturbance might be an important therapeutic target for CKD.

The Daily Expression of ABCC4 at the BCSFB Affects the Transport of Its Substrate Methotrexate

The choroid plexuses (CPs), located in the brain ventricles, form an interface between the blood and the cerebrospinal fluid named the blood-cerebrospinal barrier, which, by the presence of tight junctions, detoxification enzymes, and membrane transporters, limits the traffic of molecules into the central nervous system. It has already been shown that sex hormones regulate several CP functions, including the oscillations of its clock genes. However, it is less explored how the circadian rhythm regulates CP functions. This study aimed to evaluate the impact of sex hormones and circadian rhythms on the function of CP membrane transporters. The 24 h transcription profiles of the membrane transporters rAbca1, rAbcb1, rAbcc1, rAbcc4, rAbcg2, rAbcg4, and rOat3 were characterized in the CPs of intact male, intact female, sham-operated female, and gonadectomized rats. We found that rAbcc1 is expressed in a circadian way in the CPs of intact male rats, rAbcg2 in the CPs of intact female rats, and both rAbcc4 and rOat3 mRNA levels were expressed in a circadian way in the CPs of intact male and female rats. Next, using an in vitro model of the human blood–cerebrospinal fluid barrier, we also found that methotrexate (MTX) is transported in a circadian way across this barrier. The circadian pattern of Abcc4 found in the human CP epithelial papilloma cells might be partially responsible for MTX circadian transport across the basal membrane of CP epithelial cells.

Factors Determining Plasticity of Responses to Drugs

The plasticity of responses to drugs is an ever-present confounding factor for all aspects of pharmacology, influencing drug discovery and development, clinical use and the expectations of the patient. As an introduction to this Special Issue of the journal IJMS on pharmacological plasticity, we address the various levels at which plasticity appears and how such variability can be controlled, describing the ways in which drug responses can be affected with examples. The various levels include the molecular structures of drugs and their receptors, expression of genes for drug receptors and enzymes involved in metabolism, plasticity of cells targeted by drugs, tissues and clinical variables affected by whole body processes, changes in geography and the environment, and the influence of time and duration of changes. The article provides a rarely considered bird’s eye view of the problem and is intended to emphasize the need for increased awareness of pharmacological plasticity and to encourage further debate.

Circadian Clocks, Redox Homeostasis, and Exercise: Time to Connect the Dots?

Compelling research has documented how the circadian system is essential for the maintenance of several key biological processes including homeostasis, cardiovascular control, and glucose metabolism. Circadian clock disruptions, or losses of rhythmicity, have been implicated in the development of several diseases, premature ageing, and are regarded as health risks. Redox reactions involving reactive oxygen and nitrogen species (RONS) regulate several physiological functions such as cell signalling and the immune response. However, oxidative stress is associated with the pathological effects of RONS, resulting in a loss of cell signalling and damaging modifications to important molecules such as DNA. Direct connections have been established between circadian rhythms and oxidative stress on the basis that disruptions to circadian rhythms can affect redox biology, and vice versa, in a bi-directional relationship. For instance, the expression and activity of several key antioxidant enzymes (SOD, GPx, and CAT) appear to follow circadian patterns. Consequently, the ability to unravel these interactions has opened an exciting area of redox biology. Exercise exerts numerous benefits to health and, as a potent environmental cue, has the capacity to adjust disrupted circadian systems. In fact, the response to a given exercise stimulus may also exhibit circadian variation. At the same time, the relationship between exercise, RONS, and oxidative stress has also been scrutinised, whereby it is clear that exercise-induced RONS can elicit both helpful and potentially harmful health effects that are dependent on the type, intensity, and duration of exercise. To date, it appears that the emerging interface between circadian rhythmicity and oxidative stress/redox metabolism has not been explored in relation to exercise. This review aims to summarise the evidence supporting the conceptual link between the circadian clock, oxidative stress/redox homeostasis, and exercise stimuli. We believe carefully designed investigations of this nexus are required, which could be harnessed to tackle theories concerned with, for example, the existence of an optimal time to exercise to accrue physiological benefits.

Effect of methamphetamine on clock genes and drug-metabolizing enzyme expression

This study examined the association between clock gene expression and the effect of methamphetamine (MA) on drug-metabolizing enzymes from the perspective of drug metabolism. The relationship between expression of the clock genes BMAL1 and PER2 and the drug-metabolizing enzymes CYP3A4 and CYP2D6 was investigated using livers from autopsy cases of MA-intoxication deaths. Additionally, the effect of MA exposure on various genes was examined in HepG2 human hepatocellular carcinoma cells. Comparisons of the expression of various genes in MA users according to blood MA concentration revealed that CYP3A4 expression was similar to that of PER2, and CYP2D6 expression was similar to that of BMAL1. In cultured cell experiments, BMAL1 and CYP2D6 expression decreased depending on the time elapsed after MA addition, and PER2 and CYP3A4 expression increased slightly in a concentration-dependent manner. These results were consistent with the findings of autopsy examinations. Expression of CYP3A4 and CYP2D6 under BMAL1 and PER2 suppression, but not CYP2D6 under PER2 suppression alone, was upregulated in response to MA. These results suggest that CYPs are regulated via the clock genes BMAL1 and PER2 during MA metabolism.

Chronopharmacology in Therapeutic Drug Monitoring-Dependencies between the Rhythmics of Pharmacokinetic Processes and Drug Concentration in Blood

The objective of the optimization of pharmacotherapy compliant with the basic rules of clinical pharmacology is its maximum individualization, ensuring paramount effectiveness and security of the patient's therapy. Thus, multiple factors that are decisive in terms of uniqueness of treatment of the given patient must be taken into consideration, including, but not limited to, the patient's age, sex, concomitant diseases, special physiological conditions (e.g., pregnancy, lactation, extreme age groups), polypharmacotherapy and polypragmasia (particularly related to increased risk of drug interactions), and patient's phenotypic response to the administered drug with possible genotyping. Conducting therapy while monitoring the concentration of certain drugs in blood (Therapeutic Drug Monitoring; TDM procedure) is also one of the factors enabling treatment individualization. Furthermore, another material, and yet still a marginalized pharmacotherapeutic factor, is chronopharmacology, which indirectly determines the values of drug concentrations evaluated in the TDM procedure. This paper is a brief overview of chronopharmacology, especially chronopharmacokinetics, and its connection with the clinical interpretation of the meaning of the drug concentrations determined in the TDM procedure.

New and Emerging Approaches to Better Define Sleep Disruption and Its Consequences

Current approaches to quantify and diagnose sleep disorders and circadian rhythm disruption are imprecise, laborious, and often do not relate well to key clinical and health outcomes. Newer emerging approaches that aim to overcome the practical and technical constraints of current sleep metrics have considerable potential to better explain sleep disorder pathophysiology and thus to more precisely align diagnostic, treatment and management approaches to underlying pathology. These include more fine-grained and continuous EEG signal feature detection and novel oxygenation metrics to better encapsulate hypoxia duration, frequency, and magnitude readily possible via more advanced data acquisition and scoring algorithm approaches. Recent technological advances may also soon facilitate simple assessment of circadian rhythm physiology at home to enable sleep disorder diagnostics even for “non-circadian rhythm” sleep disorders, such as chronic insomnia and sleep apnea, which in many cases also include a circadian disruption component. Bringing these novel approaches into the clinic and the home settings should be a priority for the field. Modern sleep tracking technology can also further facilitate the transition of sleep diagnostics from the laboratory to the home, where environmental factors such as noise and light could usefully inform clinical decision-making. The “endpoint” of these new and emerging assessments will be better targeted therapies that directly address underlying sleep disorder pathophysiology via an individualized, precision medicine approach. This review outlines the current state-of-the-art in sleep and circadian monitoring and diagnostics and covers several new and emerging approaches to better define sleep disruption and its consequences.

Circadian clock core component Bmal1 dictates cell cycle rhythm of proliferating hepatocytes during liver regeneration

After partial hepatectomy (PH), the majority of remnant hepatocytes synchronously enter and rhythmically progress through the cell cycle for three major rounds to regain lost liver mass. Whether and how the circadian clock core component Bmal1 modulates this process remains elusive. We performed PH on Bmal1+/+ and hepatocyte-specific Bmal1 knockout (Bmal1hep-/-) mice and compared the initiation and progression of the hepatocyte cell cycle. After PH, Bmal1+/+ hepatocytes exhibited three major waves of nuclear DNA synthesis. In contrast, in Bmal1hep-/- hepatocytes, the first wave of nuclear DNA synthesis was delayed by 12 h, and the third such wave was lost. Following PH, Bmal1+/+ hepatocytes underwent three major waves of mitosis, whereas Bmal1hep-/- hepatocytes fully abolished mitotic oscillation. These Bmal1-dependent disruptions in the rhythmicity of hepatocyte cell cycle after PH were accompanied by suppressed expression peaks of a group of cell cycle components and regulators and dysregulated activation patterns of mitogenic signaling molecules c-Met and epidermal growth factor receptor. Moreover, Bmal1+/+ hepatocytes rhythmically accumulated fat as they expanded following PH, whereas this phenomenon was largely inhibited in Bmal1hep-/- hepatocytes. In addition, during late stages of liver regrowth, Bmal1 absence in hepatocytes caused the activation of redox sensor Nrf2, suggesting an oxidative stress state in regenerated liver tissue. Collectively, we demonstrated that during liver regeneration, Bmal1 partially modulates the oscillation of S-phase progression, fully controls the rhythmicity of M-phase advancement, and largely governs fluctuations in fat metabolism in replicating hepatocytes, as well as eventually determines the redox state of regenerated livers.NEW & NOTEWORTHY We demonstrated that Bmal1 centrally controls the synchronicity and rhythmicity of the cell cycle and lipid accumulation in replicating hepatocytes during liver regeneration. Bmal1 plays these roles, at least in part, by ensuring formation of the expression peaks of cell cycle components and regulators, as well as the timing and levels of activation of mitogenic signaling molecules.