Circadian rhythms in urinary functions: possible roles of circadian clocks?

(-)-Gallocatechin Gallate Mitigates Metabolic Syndrome-Associated Diabetic Nephropathy in db/db Mice

Metabolic syndrome (MetS) significantly predisposes individuals to diabetes and is a prognostic factor for the progression of diabetic nephropathy (DN). This study aimed to evaluate the efficacy of (-)-gallocatechin gallate (GCG) in alleviating signs of MetS-associated DN in db/db mice. We administered GCG and monitored its effects on several metabolic parameters, including food and water intake, urinary output, blood glucose levels, glucose and insulin homeostasis, lipid profiles, blood pressure, and renal function biomarkers. The main findings indicated that GCG intervention led to marked improvements in these metabolic indicators and renal function, signifying its potential in managing MetS and DN. Furthermore, transcriptome analysis revealed substantial modifications in gene expression, notably the downregulation of pro-inflammatory genes such as S100a8, S100a9, Cd44, Socs3, Mmp3, Mmp9, Nlrp3, IL-1β, Osm, Ptgs2, and Lcn2 and the upregulation of the anti-oxidative gene Gstm3. These genetic alterations suggest significant effects on pathways related to inflammation and oxidative stress. In conclusion, GCG demonstrates therapeutic efficacy for MetS-associated DN, mitigating metabolic disturbances and enhancing renal health by modulating inflammatory and oxidative responses.

Chronic Mealtime Shift Disturbs Metabolic and Urinary Functions in Mice: Effects of Daily Antioxidant Supplementation

PURPOSE

Through their biological clocks, organisms on this rotating planet can coordinate physiological processes according to the time of the day. However, the prevalence of circadian rhythm disorders has increased in modern society with the growing number of shift workers, elevating the risk of various diseases. In this study, we employed a mouse model to investigate the effects of urinary rhythm disturbances resulting from dietary changes commonly experienced by night shift workers.

METHODS

We established 3 groups based on feeding time and the use of restricted feeding: ad libitum, daytime, and early nighttime feeding. We then examined the urinary rhythm in each group. In addition to the bladder rhythm, we investigated changes in mRNA patterns within the tissues constituting the bladder. Additionally, we assessed the urination rhythm in Per1 and Per2 double-knockout mice and evaluated whether the injection of antioxidants modified the impact of mealtime shift on urination rhythm in wild-type mice.

RESULTS

Our study revealed that a shift in mealtime significantly impacted the circadian patterns of water intake and urinary excretion. In Per2::Luc knock-in mouse bladders cultured ex vivo, this shift increased the amplitude of Per2 oscillation and delayed its acrophases by several hours. Daily supplementation with antioxidants did not influence the mealtime shift-induced changes in circadian patterns of water intake and urinary excretion, nor did it affect the modified Per2 oscillation patterns in the cultured bladder. However, in aged mice, antioxidants partially restored the urinary rhythm.

CONCLUSION

A shift in mealtime meaningfully impacted the urination rhythm in mice, regardless of the presence of circadian clock genes.

A review for the impacts of circadian disturbance on urological cancers

Circadian rhythm is an internal timing system and harmonizes a variety of cellular, behavioral, and physiological processes to daily environment. Circadian disturbance caused by altered life style or disrupted sleep patterns inevitably contributes to various disorders. As the rapidly increased cancer occurrences and subsequent tremendous financial burdens, more researches focus on reducing the morbidity rather than treating it. Recently, many epidemiologic studies demonstrated that circadian disturbance was tightly related to the occurrence and development of cancers. For urinary system, numerous clinical researches observed the incidence and progress of prostate cancer were influenced by nightshift work, sleep duration, chronotypes, light exposure, and meal timing, this was also proved by many genetic and fundamental findings. Although the epidemiological studies regarding the relationship between circadian disturbance and kidney/bladder cancers were relative limited, some basic researches still claimed circadian disruption was closely correlated to these two cancers. The role of circadian chemotherapy on cancers of prostate, kidney, and bladder were also explored, however, it has not been regularly recommended considering the limited evidence and poor standard protocols. Finally, the researches for the impacts of circadian disturbance on cancers of adrenal gland, penis, testis were not found at present. In general, a better understanding the relationship between circadian disturbance and urological cancers might help to provide more scientific work schedules and rational lifestyles which finally saving health resource by reducing urological tumorigenesis, however, the underlying mechanisms are complex which need further exploration.

Circadian disturbance induces erectile dysfunction by impairing endothelial function

In order to explore the impact of circadian disturbance on erectile function, we randomly divided 24 adult male rats into groups of control (light on at 8:00 a.m. and off at 8:00 p.m.), dark/dark (DD; constant dark), light/light (LL; constant light), and shift dark/light (DL; light off at 8:00 a.m. and on at 8:00 p.m.). Four weeks later, erectile function was measured and corpora cavernosa were harvested for analysis. The maximum intracavernous pressure (mICP) and mICP/mean arterial pressure (MAP) ratio in the DD, LL, and DL groups were significantly lower than that in the control group. The LL and DL groups showed significantly attenuated endothelial nitric oxide synthase (eNOS), while DD, LL, and DL showed reduced neuronal nitric oxide synthase (nNOS) at both mRNA and protein levels. The production of nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) was inhibited by altered light/dark cycles to varying degrees. Circadian disturbance impaired endothelial function and contributed to erectile dysfunction. For the core circadian elements, mRNA expression of circadian locomotor output cycles kaput ( Clock ) and brain/muscle aryl-hydrocarbon receptor nuclear translocator-like protein 1 ( Bmal1 ) was elevated in the DL group, but their protein expression was not significantly changed. DD, LL, and DL increased period 1 ( Per1 ) and Per3 levels, while LL and DL increased PER1 levels. No significant difference was found for Per2 levels, and PER2 and PER3 concentrations were not significantly changed. Moreover, LL and DL significantly increased cryptochrome-1 (CRY1) and CRY2 at both mRNA and protein levels. The altered light/dark rat model showed that circadian disturbance contributed to erectile dysfunction probably by impairing endothelial function. Meanwhile, the core circadian elements were detected in the corpora cavernosa, but these were disrupted. However, which circadian element regulates erectile function and how it works need further analysis.

Artificial Intelligence-Based Patient Monitoring System for Medical Support

PURPOSE

In this paper, we present the development of a monitoring system designed to aid in the management and prevention of conditions related to urination. The system features an artificial intelligence (AI)-based recognition technology that automatically records a user's urination activity. Additionally, we developed a technology that analyzes movements to prevent neurogenic bladder.

METHODS

Our approach included the creation of AI-based recognition technology that automatically logs users' urination activities, as well as the development of technology that analyzes movements to prevent neurogenic bladder. Initially, we employed a recurrent neural network model for the urination activity recognition technology. For predicting the risk of neurogenic bladder, we utilized convolutional neural network (CNN)-based AI technology.

RESULTS

The performance of the proposed system was evaluated using a study population of 30 patients with urinary tract dysfunction, who collected data over a 60-day period. The results demonstrated an average accuracy of 94.2% in recognizing urinary tract activity, thereby confirming the effectiveness of the recognition technology. Furthermore, the motion analysis technology for preventing neurogenic bladder, which also employed CNN-based AI, showed promising results with an average accuracy of 83%.

CONCLUSION

In this study, we developed a urination disease monitoring system aimed at predicting and managing risks for patients with urination issues. The system is designed to support the entire care cycle of a patient by leveraging AI technology that processes various image and signal data. We anticipate that this system will evolve into digital treatment products, ultimately providing therapeutic benefits to patients.

Managing fuels and fluids: Network integration of osmoregulatory and metabolic hormonal circuits in the polymodal control of homeostasis in insects

Osmoregulation in insects is an essential process whereby changes in hemolymph osmotic pressure induce the release of diuretic or antidiuretic hormones to recruit individual osmoregulatory responses in a manner that optimizes overall homeostasis. However, the mechanisms by which different osmoregulatory circuits interact with other homeostatic networks to implement the correct homeostatic program remain largely unexplored. Surprisingly, recent advances in insect genetics have revealed several important metabolic functions are regulated by classic osmoregulatory pathways, suggesting that internal cues related to osmotic and metabolic perturbations are integrated by the same hormonal networks. Here, we review our current knowledge on the network mechanisms that underpin systemic osmoregulation and discuss the remarkable parallels between the hormonal networks that regulate body fluid balance and those involved in energy homeostasis to provide a framework for understanding the polymodal optimization of homeostasis in insects.

Circadian rhythms in colonic function

A rhythmic expression of clock genes occurs within the cells of multiple organs and tissues throughout the body, termed "peripheral clocks." Peripheral clocks are subject to entrainment by a multitude of factors, many of which are directly or indirectly controlled by the light-entrainable clock located in the suprachiasmatic nucleus of the hypothalamus. Peripheral clocks occur in the gastrointestinal tract, notably the epithelia whose functions include regulation of absorption, permeability, and secretion of hormones; and in the myenteric plexus, which is the intrinsic neural network principally responsible for the coordination of muscular activity in the gut. This review focuses on the physiological circadian variation of major colonic functions and their entraining mechanisms, including colonic motility, absorption, hormone secretion, permeability, and pain signalling. Pathophysiological states such as irritable bowel syndrome and ulcerative colitis and their interactions with circadian rhythmicity are also described. Finally, the classic circadian hormone melatonin is discussed, which is expressed in the gut in greater quantities than the pineal gland, and whose exogenous use has been of therapeutic interest in treating colonic pathophysiological states, including those exacerbated by chronic circadian disruption.

A melanopsin ganglion cell subtype forms a dorsal retinal mosaic projecting to the supraoptic nucleus

Visual input to the hypothalamus from intrinsically photosensitive retinal ganglion cells (ipRGCs) influences several functions including circadian entrainment, body temperature, and sleep. ipRGCs also project to nuclei such as the supraoptic nucleus (SON), which is involved in systemic fluid homeostasis, maternal behavior, social behaviors, and appetite. However, little is known about the SON-projecting ipRGCs or their relationship to well-characterized ipRGC subtypes. Using a GlyT2Cre mouse line, we show a subtype of ipRGCs restricted to the dorsal retina that selectively projects to the SON. These ipRGCs tile a dorsal region of the retina, forming a substrate for encoding ground luminance. Optogenetic activation of their axons demonstrates they release the neurotransmitter glutamate in multiple regions, including the suprachiasmatic nucleus (SCN) and SON. Our results challenge the idea that ipRGC dendrites overlap to optimize photon capture and suggests non-image forming vision operates to sample local regions of the visual field to influence diverse behaviors.

Role of circadian rhythms and melatonin in bladder function in heath and diseases

The circadian system modulates all visceral organ physiological processes including urine storage and voiding. The "master clock" of the circadian system lies within suprachiasmatic nucleus of the hypothalamus while "peripheral clocks" are found in most peripheral tissue and organs, including the urinary bladder. Disruptions of circadian rhythms can cause organ malfunction and disorder or exacerbate pre-existing ones. It has been suggested that nocturia, which develops mostly in the elderly, could be a circadian-related disorder of the bladder. In the bladder, many types of gap junctions and ion channels in the detrusor, urothelium and sensory nerves are likely under strict local peripheral circadian control. The pineal hormone, melatonin, is a circadian rhythm synchroniser capable of controlling a variety of physiological processes in the body. Melatonin predominantly acts via the melatonin 1 and melatonin 2 G-protein coupled receptors expressed in the central nervous system, and many peripheral organs and tissues. Melatonin could be beneficial in the treatment of nocturia and other common bladder disorders. The ameliorating action of melatonin on bladder function is likely due to multiple mechanisms which include central effects on voiding and peripheral effects on the detrusor and bladder afferents. More studies are warranted to determine the precise mechanisms of circadian rhythm coordination of the bladder function and melatonin influences on the bladder in health and diseases.

Glucocorticoids coordinate the bladder peripheral clock and diurnal micturition pattern in mice

Peripheral clocks function to regulate each organ and are synchronized though various molecular and behavioral signals. However, signals that entrain the bladder clock remain elusive. Here, we show that glucocorticoids are a key cue for the bladder clock in vitro and in vivo. A pBmal1-dLuc human urothelial cell-line showed significant shifts in gene expression after cortisol treatment. In vivo, rhythmic bladder clock gene expression was unchanged by bilateral adrenalectomy but shifted 4 h forward by corticosterone administration at the inactive phase. Moreover, the bladder clock shifted 8-12 h in mice that underwent both bilateral adrenalectomy and corticosterone administration at the inactive phase. These mice showed decreases in the diurnal rhythm of volume voided per micturition, while maintaining diurnal activity rhythms. These results indicate that the diurnal rhythm of glucocorticoid signaling is a zeitgeber that overcomes other bladder clock entrainment factors and coordinates the diurnal rhythm of volume voided per micturition.

Cyrcadian Rhythm, Mood, and Temporal Patterns of Eating Chocolate: A Scoping Review of Physiology, Findings, and Future Directions

This paper discusses the effect of chrononutrition on the regulation of circadian rhythms; in particular, that of chocolate on the resynchronization of the human internal biological central and peripheral clocks with the main external synchronizers, light–dark cycle and nutrition-fasting cycle. The desynchronization of internal clocks with external synchronizers, which is so frequent in our modern society due to the tight rhythms imposed by work, social life, and technology, has a negative impact on our psycho-physical performance, well-being, and health. Taking small amounts of chocolate, in the morning at breakfast at the onset of the active phase, helps speed up resynchronization time. The high flavonoid contents in chocolate promote cardioprotection, metabolic regulation, neuroprotection, and neuromodulation with direct actions on brain function, neurogenesis, angiogenesis, and mood. Although the mechanisms of action of chocolate compounds on brain function and mood as well as on the regulation of circadian rhythms have yet to be fully understood, data from the literature currently available seem to agree in suggesting that chocolate intake, in compliance with chrononutrition, could be a strategy to reduce the negative effects of desynchronization. This strategy appears to be easily implemented in different age groups to improve work ability and daily life.

Piezo channels in the urinary system

The Piezo channel family, including Piezo1 and Piezo2, includes essential mechanosensitive transduction molecules in mammals. Functioning in the conversion of mechanical signals to biological signals to regulate a plethora of physiological processes, Piezo channels, which have a unique homotrimeric three-blade propeller-shaped structure, utilize a cap-motion and plug-and-latch mechanism to gate their ion-conducting pathways. Piezo channels have a wide range of biological roles in various human systems, both in vitro and in vivo. Currently, there is a lack of comprehensive understanding of their antagonists and agonists, and therefore further investigation is needed. Remarkably, increasingly compelling evidence demonstrates that Piezo channel function in the urinary system is important. This review article systematically summarizes the existing evidence of the importance of Piezo channels, including protein structure, mechanogating mechanisms, and pharmacological characteristics, with a particular focus on their physiological and pathophysiological roles in the urinary system. Collectively, this review aims to provide a direction for future clinical applications in urinary system diseases.

Daily injection of melatonin inhibits insulin resistance induced by chronic mealtime shift

Shift work disorders have become an emerging concern worldwide. Shift disorders encompass a wide range of illnesses that have yet to be identified. The study focused on the relationship between shift work disorders and insulin resistance. Previously, it was reported that advancing the usual mealtime of mice triggered insulin resistance. Here, the hypothesis that chronic mealtime shifts induce oxidative damage leading to chronic diseases such as type 2 diabetes was tested. It was found that mealtime shift causes imbalances between anti-oxidative capacity and reactive oxygen species (ROS) levels, indicating increased oxidative damage during the light/rest phase. This study further demonstrated that daily supplementation of antioxidants at the appropriate time of day inhibited insulin resistance caused by chronic mealtime shifts, suggesting significant and chronic health implications for shift workers. In conclusion, it was confirmed that increased ROS levels caused by mealtime shift induce insulin resistance, which is inhibited by the antioxidant melatonin.

The potential impacts of circadian rhythm disturbances on male fertility

A circadian rhythm is an internalized timing system that synchronizes the cellular, behavioral, and physiological processes of organisms to the Earth's rotation. Because all physiological activities occur at a specific time, circadian rhythm disturbances can lead to various pathological disorders and diseases. Growing evidence has shown that the circadian clock is tightly connected to male fertility, and circadian perturbations contribute to infertility. The night shiftwork, insufficient sleep, and poor sleep quality are common causes of circadian disturbances, and many studies have reported that they impair sperm quality and increase the risk of male infertility. However, research on the impacts of light, body temperature, and circadian/circannual rhythms is relatively lacking, although some correlations have been demonstrated. Moreover, as the index of sperm quality was diverse and study designs were non-uniform, the conclusions were temporarily inconsistent and underlying mechanisms remain unclear. A better understanding of whether and how circadian disturbances regulate male fertility will be meaningful, as more scientific work schedules and rational lifestyles might help improve infertility.

Physiological rhythms are influenced by photophase wavelength in a nocturnal and a diurnal rodent species from South Africa

The quality and quantity of light changes significantly over the course of the day. The effect of light intensity on physiological and behavioural responses of animals has been well documented, particularly during the scotophase, but the effect of the wavelength of light, particularly during the photophase, less so. We assessed the daily responses in urine production, urinary 6-sulfatoxymelatonin (6-SMT) and glucocorticoid metabolite (uGCM) concentrations in the nocturnal Namaqua rock mouse (Micaelamys namaquensis) and diurnal four striped field mouse (Rhabdomys pumilio) under varying wavelengths of near monochromatic photophase (daytime) lighting. Animals were exposed to a short-wavelength light cycle (SWLC; ∼465-470 nm), a medium-wavelength light cycle (MWLC; ∼515-520 nm) and a long-wavelength light cycle (LWLC; ∼625-630 nm). The SWLC significantly attenuated mean daily urine production rates and the mean daily levels of urinary 6-SMT and of uGCM were inversely correlated with wavelength in both species. The presence of the SWLC greatly augmented overall daily 6-SMT levels, and simultaneously led to the highest uGCM concentrations in both species. In M. namaquensis, the urine production rate and urinary 6-SMT concentrations were significantly higher during the scotophase compared to the photophase under the SWLC and MWLC, whereas the uGCM concentrations were significantly higher during the scotophase under all WLCs. In R. pumilio, the urine production rate and uGCM were significantly higher during the scotophase of the SWLC, not the MWLC and LWLC. Our results illustrate that wavelength in the photophase plays a central role in the entrainment of rhythms in diurnal and nocturnal African rodent species.

Gene expression profiles during tissue remodeling following bladder outlet obstruction

Bladder outlet obstruction (BOO) often results in lower urinary tract symptoms (LUTSs) and negatively affects quality of life. Here, we evaluated gene expression patterns in the urinary bladder during tissue remodeling due to BOO. We divided BOO model rats into two groups according to the degree of hypertrophy of smooth muscle in the bladder. The strong muscular hypertrophy group, which exhibited markedly increased bladder smooth muscle proportion and HIF1α mRNA levels compared with the control group, was considered a model for the termination of hypertrophy, whereas the mild muscular hypertrophy group was considered a model of the initiation of hypertrophy. Some genes related to urinary function showed different expression patterns between the two groups. Furthermore, we found that several genes, including D-box binding PAR bZIP transcription factor (DBP), were upregulated only in the mild muscular hypertrophy group. DBP expression levels were increased in bladder smooth muscle cells in response to hypoxic stress. DBP associated with enhancer and promoter regions of NOS3 gene locus and upregulated NOS3 gene expression under hypoxic conditions. These findings suggested that the regulatory systems of gene expression were altered during tissue remodeling following BOO. Furthermore, circadian clock components might be involved in control of urinary function via transcriptional gene regulation in response to hypoxic stimuli.

Characterization of Lower Urinary Tract Dysfunction after Thoracic Spinal Cord Injury in Yucatan Minipigs

There is an increasing need to develop approaches that will not only improve the clinical management of neurogenic lower urinary tract dysfunction (NLUTD) after spinal cord injury (SCI), but also advance therapeutic interventions aimed at recovering bladder function. Although pre-clinical research frequently employs rodent SCI models, large animals such as the pig may play an important translational role in facilitating the development of devices or treatments. Therefore, the objective of this study was to develop a urodynamics protocol to characterize NLUTD in a porcine model of SCI. An iterative process to develop the protocol to perform urodynamics in female Yucatan minipigs began with a group of spinally intact, anesthetized pigs. Subsequently, urodynamic studies were performed in a group of awake, lightly restrained pigs, before and after a contusion-compression SCI at the T2 or T9-T11 spinal cord level. Bladder tissue was obtained for histological analysis at the end of the study. All anesthetized pigs had bladders that were acontractile, which resulted in overflow incontinence once capacity was reached. Uninjured, conscious pigs demonstrated appropriate relaxation and contraction of the external urethral sphincter during the voiding phase. SCI pigs demonstrated neurogenic detrusor overactivity and a significantly elevated post-void residual volume. Relative to the control, SCI bladders were heavier and thicker. The developed urodynamics protocol allows for repetitive evaluation of lower urinary tract function in pigs at different time points post-SCI. This technique manifests the potential for using the pig as an intermediary, large animal model for translational studies in NLUTD.

Minimally Invasive Ways of Determining Circadian Rhythms in Humans

Circadian rhythm exerts a critical role in mammalian health and disease. A malfunctioning circadian clock can be a consequence, as well as the cause of several pathophysiologies. Clinical therapies and research may also be influenced by the clock. Since the most suitable manner of revealing this rhythm in humans is not yet established, we discuss existing methods and seek to determine the most feasible ones.

The Role of Purinergic Receptors in the Circadian System

The circadian system is an internal time-keeping system that synchronizes the behavior and physiology of an organism to the 24 h solar day. The master circadian clock, the suprachiasmatic nucleus (SCN), resides in the hypothalamus. It receives information about the environmental light/dark conditions through the eyes and orchestrates peripheral oscillators. Purinergic signaling is mediated by extracellular purines and pyrimidines that bind to purinergic receptors and regulate multiple body functions. In this review, we highlight the interaction between the circadian system and purinergic signaling to provide a better understanding of rhythmic body functions under physiological and pathological conditions.

Circadian clock and cancer: From a viewpoint of cellular differentiation

The circadian clock controls and adapts diverse physiological and behavioral processes according to Earth's 24-h cycle of environmental changes. The master pacemaker of the mammalian circadian clock resides in the hypothalamic suprachiasmatic nucleus, but almost all cells throughout the body show circadian oscillations in gene expression patterns and associated functions. Recent studies have shown that the circadian clock gradually develops during embryogenesis. Embryonic stem cells and induced pluripotent stem cells do not show circadian oscillations of gene expression, but gradually develop circadian clock oscillation during differentiation; thus, the developmental program of circadian clock emergence appears closely associated with cellular differentiation. Like embryonic stem cells, certain cancer cell types also lack the circadian clock. Given this similarity between embryonic stem cells and cancer cells, interest is growing in the contributions of circadian clock dysfunction to dedifferentiation and cancer development. In this review, we summarize recent advances in our understanding of circadian clock emergence during ontogenesis, and discuss possible associations with cellular differentiation and carcinogenesis. Considering the multiple physiological functions of circadian rhythms, circadian abnormalities might contribute to a host of diseases, including cancer. Insights on circadian function could lead to the identification of biomarkers for cancer diagnosis and prognosis, as well as novel targets for treatment.

Influence of Circadian Disruption Associated With Artificial Light at Night on Micturition Patterns in Shift Workers

Shift workers often experience problems associated with circadian disruption associated with artificial light at night and nocturia is commonly noted in night-shift workers. Nocturia associated with circadian disruption is due to increased urine production of the kidney and decreased storage function of the bladder. A recent discovery of peripheral clock genes in the bladder and their role in contractile property of the bladder support that micturition is closely related to the circadian rhythm. Moreover, there are clinical studies showed that shift workers more often experienced nocturia due to circadian disruption. However, comparing with other health problems, concerns on nocturia and voiding dysfunction associated with circadian disruption are insufficient. Therefore, further studies about voiding dysfunction associated with the circadian disruption in shift workers are necessary.

The effect of a multidisciplinary weight loss program on renal circadian rhythm in obese adolescents

Adolescent obesity is a serious health problem associated with many comorbidities. Obesity-related alterations in circadian rhythm have been described for nocturnal blood pressure and for metabolic functions. We believe renal circadian rhythm is also disrupted in obesity, though this has not yet been investigated. This study aimed to examine renal circadian rhythm in obese adolescents before and after weight loss.In 34 obese adolescents (median age 15.7 years) participating in a residential weight loss program, renal function profiles and blood samples were collected at baseline, after 7 months, and again after 12 months of therapy. The program consisted of dietary restriction, increased physical activity, and psychological support. The program led to a median weight loss of 24 kg and a reduction in blood pressure. Initially, lower diurnal free water clearance (- 1.08 (- 1.40-- 0.79) mL/min) was noticed compared with nocturnal values (0.75 (- 0.89-- 0.64) mL/min). After weight loss, normalization of this inverse rhythm was observed (day - 1.24 (- 1.44-1.05) mL/min and night - 0.98 (- 1.09-- 0.83) mL/min). A clear circadian rhythm in diuresis rate and in renal clearance of creatinine, solutes, sodium, and potassium was seen at all time points. Furthermore, we observed a significant increase in sodium clearance. Before weight loss, daytime sodium clearance was 0.72 mL/min (0.59-0.77) and nighttime clearance was 0.46 mL/min (0.41-0.51). After weight loss, daytime clearance increased to 0.99 mL/min (0.85-1.17) and nighttime clearance increased to 0.78 mL/min (0.64-0.93).Conclusion: In obese adolescents, lower diurnal free water clearance was observed compared with nocturnal values. Weight loss led to a normalization of this inverse rhythm, suggesting a recovery of the anti-diuretic hormone activity. Both before and after weight loss, clear circadian rhythm of diuresis rate and renal clearance of creatinine, solutes, sodium, and potassium was observed.What is Known:• Obesity-related alterations in circadian rhythm have been described for nocturnal blood pressure and for metabolic functions. We believe renal circadian rhythm is disrupted in obesity, though this has not been investigated yet.What is New:• In obese adolescents, an inverse circadian rhythm of free water clearance was observed, with higher nighttime free water clearance compared with daytime values. Weight loss led to a normalization of this inverse rhythm, suggesting a recovery of the anti-diuretic hormone activity.• Circadian rhythm in diuresis rate and in the renal clearance of creatinine, solutes, sodium, and potassium was preserved in obese adolescents and did not change after weight loss.

Sex-, feeding-, and circadian time-dependency of P-glycoprotein expression and activity - implications for mechanistic pharmacokinetics modeling

P-glycoprotein (P-gp) largely influences the pharmacokinetics (PK) and toxicities of xenobiotics in a patient-specific manner so that personalized drug scheduling may lead to significant patient's benefit. This systems pharmacology study investigated P-gp activity in mice according to organ, sex, feeding status, and circadian time. Sex-specific circadian changes were found in P-gp ileum mRNA and protein levels, circadian amplitudes being larger in females as compared to males. Plasma, ileum and liver concentrations of talinolol, a pure P-gp substrate, significantly differed according to sex, feeding and circadian timing. A physiologically-based PK model was designed to recapitulate these datasets. Estimated mesors (rhythm-adjusted mean) of ileum and hepatic P-gp activity were higher in males as compared to females. Circadian amplitudes were consistently higher in females and circadian maxima varied by up to 10 h with respect to sex. Fasting increased P-gp activity mesor and dampened its rhythm. Ex-vivo bioluminescence recordings of ileum mucosae from transgenic mice revealed endogenous circadian rhythms of P-gp protein expression with a shorter period, larger amplitude, and phase delay in females as compared to males. Importantly, this study provided model structure and parameter estimates to refine PK models of any P-gp substrate to account for sex, feeding and circadian rhythms.

Identification of self-regulatory network motifs in reverse engineering gene regulatory networks using microarray gene expression data

Gene Regulatory Networks (GRNs) are reconstructed from the microarray gene expression data through diversified computational approaches. This process ensues in symmetric and diagonal interaction of gene pairs that cannot be modelled as direct activation, inhibition, and self-regulatory interactions. The values of gene co-expressions could help in identifying co-regulations among them. The proposed approach aims at computing the differences in variances of co-expressed genes rather than computing differences in values of mean expressions across experimental conditions. It adopts multivariate co-variances using principal component analysis (PCA) to predict an asymmetric and non-diagonal gene interaction matrix, to select only those gene pair interactions that exhibit the maximum variances in gene regulatory expressions. The asymmetric gene regulatory interactions help in identifying the controlling regulatory agents, thus lowering the false positive rate by minimizing the connections between previously unlinked network components. The experimental results on real as well as in silico datasets including time-series RTX therapy, Arabidopsis thaliana, DREAM-3, and DREAM-8 datasets, in comparison with existing state-of-the-art approaches demonstrated the enhanced performance of the proposed approach for predicting positive and negative feedback loops and self-regulatory interactions. The generated GRNs hold the potential in determining the real nature of gene pair regulatory interactions.

A comprehensive review of adult enuresis

Nocturnal enuresis (NE) is a combined symptom of nocturia and urinary incontinence. In this review, we aim to summarize the current literature on NE in terms of its definition, diagnosis, and management. Recommended diagnostic evaluation of NE includes a focused history and physical examination, urinalysis, and when indicated, ultrasound examination, flow rate, urine volume chart, urodynamics, and cystoscopy. Therapeutic options include lifestyle modification and medications (i.e., desmopressin and anticholinergics).

Personalized Urination Activity Recognition Based on a Recurrent Neural Network Using Smart Band

Purpose

Though it is very important obtaining exact data about patients’ voiding patterns for managing voiding dysfunction, actual practice is very difficult and cumbersome. In this study, data about urination time and interval measured by smart band device on patients’ wrist were collected and analyzed to resolve the clinical arguments about the efficacy of voiding diary. By developing a smart band based algorithm for recognition of complex and serial pattern of motion, this study aimed to explore the feasibility of measurement the urination time and intervals for voiding dysfunction management.

Methods

We designed a device capable of recognizing urination time and intervals based on specific postures of the patient and consistent changes in posture. These motion data were obtained by a smart band worn on the wrist. An algorithm that recognizes the repetitive and common 3-step behavior for urination (forward movement, urination, backward movement) was devised based on the movement and tilt angle data collected from a 3-axis accelerometer. The sequence of body movements during voiding has consistent temporal characteristics, so we used a recurrent neural network and long short-term memory based framework to analyze the sequential data and to recognize urination time. Real-time data were acquired from the smart band, and for data corresponding to a certain duration, the value of the signals was calculated and then compared with the set analysis model to calculate the time of urination. A comparative study was conducted between real voiding and device-detected voiding to assess the performance of the proposed recognition technology.

Results

The accuracy of the algorithm was calculated based on clinical guidelines established by urologists. The accuracy of this detecting device was high (up to 94.2%), proving the robustness of the proposed algorithm.

Conclusions

This urination behavior recognition technology showed high accuracy and could be applied in clinical settings to characterize patients’ voiding patterns. As wearable devices are developed and generalized, algorithms detecting consistent sequential body movement patterns reflecting specific physiologic behavior might be a new methodology for studying human physiologic behavior.

The effects of sucrose on urine collection in metabolic cages

Representative urine collection that respects the standards of animal welfare is still an issue in experimental nephrology. The commonly used metabolic cages induce stress in rodents. In mice, the volume of collected urine is sometimes insufficient for further analysis. The aim of this experiment was to analyse the effects of time of day, temperature and 2%, 5% or 10% sucrose solutions on diuresis, weight change and liquid intake of adult mice placed in metabolic cages for urine collection. Mice were placed in metabolic cages for 12 h during the day or night at standard ambient (22℃) and thermoneutral (28℃) temperatures. To determine the effect of acclimatisation, mice were placed in metabolic cages for five consecutive days. Diuresis increased with concentrations of sucrose. Body weight reduction was most rapid in the group given tap water and decreased with increasing sucrose concentrations. A drastic drop in body weight was observed in mice placed in metabolic cages for four consecutive days with access to tap water and food, indicating that time spent in metabolic cages should be kept to a minimum, as prolonged confinement in metabolic cages can be harmful to mice. The administration of concentrated sucrose solutions can potentially aid in mouse urine collection by reducing the time spent in metabolic cages. Sucrose supplementation increased the albumin/creatinine ratio. However, without showing estimates of glomerular filtration rate, renal haemodynamics, plasma electrolytes and urinary electrolyte excretions, the results of this study do not provide any conclusion about the effect of sucrose on renal function.

Circadian regulation of renal function

The kidneys regulate many vital functions that require precise control throughout the day. These functions, such as maintaining sodium balance or regulating arterial pressure, rely on an intrinsic clock mechanism that was commonly believed to be controlled by the central nervous system. Mounting evidence in recent years has unveiled previously underappreciated depth of influence by circadian rhythms and clock genes on renal function, at the molecular and physiological level, independent of other external factors. The impact of circadian rhythms in the kidney also affects individuals from a clinical standpoint, as the loss of rhythmic activity or clock gene expression have been documented in various cardiovascular diseases. Fortunately, the prognostic value of examining circadian rhythms may prove useful in determining the progression of a kidney-related disease, and chronotherapy is a clinical intervention that requires consideration of circadian and diurnal rhythms in the kidney. In this review, we discuss evidence of circadian regulation in the kidney from basic and clinical research in order to provide a foundation on which a great deal of future research is needed to expand our understanding of circadian relevant biology.

Sleep Problems are Associated with Development and Progression of Lower Urinary Tract Symptoms: Results from REDUCE

PURPOSE

Although lower urinary tract symptoms and sleep problems often develop together, to our knowledge it is unknown whether sleep disturbances are linked to lower urinary tract symptoms development and progression. As measured by the 6-item MOS-Sleep (Medical Outcomes Study Sleep Scale) survey we examined the relationship between sleep problems, and the development and progression of lower urinary tract symptoms in the REDUCE (Reduction by Dutasteride of Prostate Cancer Events) study.

MATERIALS AND METHODS

REDUCE was a randomized trial testing prostate cancer chemoprevention with dutasteride in men with prostate specific antigen 2.5 to 10 ng/ml and a negative biopsy. At baseline men completed MOS-Sleep and a scaled average was used to calculate the sleep score. Men were followed for 4 years and I-PSS (International Prostate Symptom Score) was completed at baseline and every 6 months. Asymptomatic men had I-PSS less than 8 while symptomatic men had I-PSS 8 or greater. In the placebo arm of 2,588 men not receiving α-blockers or 5α-reductase inhibitors at baseline we tested the association between sleep problems and lower urinary tract symptom development and progression using Cox models.

RESULTS

During followup lower urinary tract symptoms developed in 209 of 1,452 asymptomatic men (14%) and 580 of 1,136 (51%) with lower urinary tract symptoms demonstrated progression. On multivariable analysis higher sleep scores were suggestively associated with increased lower urinary tract symptoms in asymptomatic men (quartile 4 vs 1 HR 1.41, 95% CI 0.92-2.17, p = 0.12) and with lower urinary tract symptom progression in symptomatic men (per 10 points of sleep score HR 1.06, 95% CI 1.01-1.12, p = 0.029).

CONCLUSIONS

Among men with lower urinary tract symptoms worse sleep scores were associated with the progression of lower urinary tract symptoms and among asymptomatic men worse sleep scores were suggestively associated with the development of lower urinary tract symptoms. If confirmed, these data suggest that sleep problems may precede such symptoms. Whether treating sleep problems would improve lower urinary tract symptoms requires further testing.

Mood, the Circadian System, and Melanopsin Retinal Ganglion Cells

The discovery of a third type of photoreceptors in the mammalian retina, intrinsically photosensitive retinal ganglion cells (ipRGCs), has had a revolutionary impact on chronobiology. We can now properly account for numerous non-vision-related functions of light, including its effect on the circadian system. Here, we give an overview of ipRGCs and their function as it relates specifically to mood and biological rhythms. Although circadian disruptions have been traditionally hypothesized to be the mediators of light's effects on mood, here we present an alternative model that dispenses with assumptions of causality between the two phenomena and explains mood regulation by light via another ipRGC-dependent mechanism.

Development of Personalized Urination Recognition Technology Using Smart Bands

Purpose

This study collected and analyzed activity data sensed through smart bands worn by patients in order to resolve the clinical issues posed by using voiding charts. By developing a smart band-based algorithm for recognizing urination activity in patients, this study aimed to explore the feasibility of urination monitoring systems.

Methods

This study aimed to develop an algorithm that recognizes urination based on a patient’s posture and changes in posture. Motion data was obtained from a smart band on the arm. An algorithm that recognizes the 3 stages of urination (forward movement, urination, backward movement) was developed based on data collected from a 3-axis accelerometer and from tilt angle data. Real-time data were acquired from the smart band, and for data corresponding to a certain duration, the absolute value of the signals was calculated and then compared with the set threshold value to determine the occurrence of vibration signals. In feature extraction, the most essential information describing each pattern was identified after analyzing the characteristics of the data. The results of the feature extraction process were sorted using a classifier to detect urination.

Results

An experiment was carried out to assess the performance of the recognition technology proposed in this study. The final accuracy of the algorithm was calculated based on clinical guidelines for urologists. The experiment showed a high average accuracy of 90.4%, proving the robustness of the proposed algorithm.

Conclusions

The proposed urination recognition technology draws on acceleration data and tilt angle data collected via a smart band; these data were then analyzed using a classifier after comparative analyses with standardized feature patterns.

Effects of photophase illuminance on locomotor activity, urine production and urinary 6-sulfatoxymelatonin in nocturnal and diurnal South African rodents

Effects of photophase illuminance (1, 10, 100 and 330 lx of white incandescent lighting) on daily rhythms of locomotor activity, urine production and 6-sulfatoxymelatonin (6-SMT; 10 versus 330 lx) were studied in nocturnal Namaqua rock mice (Micaelamys namaquensis) and diurnal four-striped field mice (Rhabdomys pumilio). Micaelamys namaquensis was consistently nocturnal (∼90-94% nocturnal activity), whereas considerable individual variation marked activity profiles in R. pumilio, but with activity mostly pronounced around twilight (∼55-66% diurnal activity). The amplitude of daily activity was distinctly affected by light intensity and this effect was greater in M. namaquensis than in R. pumilio Only M. namaquensis displayed a distinctive daily rhythm of urine production, which correlated with its activity rhythm. Mean daily urine production appeared to be attenuated under dim photophase conditions, particularly in R. pumilio The results suggest that the circadian regulation of locomotor activity and urine production possesses separate sensitivity thresholds to photophase illuminance. Micaelamys namaquensis expressed a significant daily 6-SMT rhythm that peaked during the late night, but the rhythm was attenuated by the brighter photophase cycle (330 lx). Rhabdomys pumilio appeared to express an ultradian 6-SMT rhythm under both lighting regimes with comparable mean daily 6-SMT values, but with different temporal patterns. It is widely known that a natural dark phase which is undisturbed by artificial light is essential for optimal circadian function. Here, we show that light intensity during the photophase also plays a key role in maintaining circadian rhythms in rodents, irrespective of their temporal activity rhythm.

Clinical Assessment of Urinary Tract Damage during Sustained-Release Estrogen Supplementation in Mice

Estrogen supplementation is a key component of numerous mouse research models but can adversely affect the urinary system. The goal of this study was to develop a clinical scoring system and identify biomarkers of occult urinary tract lesions prior to the development of systemic illness in mice. Ovariectomized or sham-surgery SCID mice were implanted subcutaneously with a placebo pellet or one containing sustained-release estradiol (0.18 mg 60-d release 17β-estradiol). Mice were assessed twice weekly for 4 to 6 wk by using a clinical scoring system that included body condition, general activity, posture, hair coat, hydration, abdominal distension, urine staining of coat and skin, and ability to urinate. Samples were collected weekly for urinalysis, BUN, creatinine, and serum estradiol levels. Terminal samples were analyzed for histopathologic lesions. Compared with placebo controls, estradiolsupplemented mice had higher serum estradiol levels at weeks 2 and 3; significant differences in total clinical scores by the 3-wk time point; and in body condition, general activity, posture, hair coat, and urine staining scores by the 6-wk terminal time point. Urinary tract lesions included hydronephrosis, pyelonephritis, cystitis, and urolithiasis. All mice with urolithiasis had crystalluria, and 5 of the 6 mice with pyelonephritis or hydroureter had dilute urine (that is, specific gravity less than 1.030). However, these findings were not specific to mice with lesions. A total clinical score of 3.5 (maximum, 24) identified estradiol-supplemented mice with 83% specificity and 50% sensitivity, but no single clinical parameter, biomarker, or the total clinical score accurately predicted occult urinary tract lesions. Considering the lesions we observed, prudence is warranted when using pelleted sustained-release estradiol in mice, and important parameters to monitor for animal health include urine staining, body condition score, urine sediment, and urine specific gravity.

Nocturia: The circadian voiding disorder

Nocturia is a prevalent condition of waking to void during the night. The concept of nocturia has evolved from being a symptomatic aspect of disease associated with the prostate or bladder to a form of lower urinary tract disorder. However, recent advances in circadian biology and sleep science suggest that it might be important to consider nocturia as a form of circadian dysfunction. In the current review, nocturia is reexamined with an introduction to sleep disorders and recent findings in circadian biology in an attempt to highlight the importance of rediscovering nocturia as a problem of chronobiology.

Hepcidin-2 in mouse urine as a candidate radiation-responsive molecule

We used high-performance liquid chromatography to separate urine obtained from whole-body gamma-irradiated mice (4 Gy) before analyzing each fraction with matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry to identify radiation-responsive molecules. We identified two candidates: hepcidin antimicrobial peptide 2 (hepcidin-2) and peptide fragments of kidney androgen-regulated protein (KAP). We observed that peak increases of hepcidin-2 in urine were delayed in a dose-dependent manner (1 Gy and above); however, the amount of KAP peptide fragments showed no correlation with radiation dose. In addition, an increase in hepcidin-2 after exposure to relatively low radiation doses (0.25 and 0.5 Gy, respectively) was biphasic (at 8-48 h and 120-168 h, respectively, after irradiation). The increase in hepcidin-2 paralleled an increase in hepcidin-2 gene (Hamp2) mRNA levels in the liver. These results suggest that radiation exposure directly or indirectly induces urinary excretion of hepcidin-2 at least in part by the upregulation of Hamp2 mRNA in the liver.

How Protective Mechanisms Interact to Prevent Overnight Calcium Phosphate Precipitation - An Observational Study to Determine Factors Against Calcium Phosphate Lithogenesis in a Healthy Cohort

BACKGROUND/AIMS

As restful, non-interrupted sleep is essential for normal mental and physical functioning, the urine flow rate (UFR) overnight remains low. Due to this reduced UFR, the kidneys produce a lower urine volume, which may lead to supersaturation of lithogens in the renal collecting system. The protective mechanisms that prevent the rise in the concentration of the lithogenic substances in urine, such as calcium phosphate, are explored.

METHODS

Urine samples were collected from 26 subjects every 2-3 h during daylight with one nocturnal collection; the UFR was calculated in the median time for each collection period. Urinary constituents for calcium phosphate precipitation including electrolytes, calcium, phosphate, citrate, and pH were measured. Comparisons within individuals were done by paired t test.

RESULTS

The calcium excretion rate fell significantly overnight (from 2.4 ± 0.2 µmol/min during the daytime to 1.5 ± 0.3 µmol/min, p < 0.05), in parallel with sodium excretion (54 ± 16 µmol/min from its daytime 127 ± 12 µmol/min, p < 0.05), preventing nocturnal calcium concentration from increasing (3.0 ± 0.3 mmol/l daytime to 2.5 ± 0.5 mmol/l overnight), while citrate concentration did not change significantly. The total urine phosphate concentration rose significantly overnight (daytime 18.7 ± 1.4 µmol/min vs. nocturnal 20.9 ± 1.7 µmol/min), but the concentration of divalent phosphate did not increase in the overnight period.

CONCLUSIONS

Although the UFR was lower overnight, there was no evidence that the risk of calcium phosphate precipitate formation in healthy subjects was increased.

Do rotational shifts affect micturition patterns in real practice? A pilot study in healthy, young female nurses

Purpose

Healthy, young individuals are known to exhibit circadian variation in urinary functions. However, the effects of chronic circadian disturbance on voiding functions are largely unknown. The present work compared the effects of rotational shifts on the micturition patterns of female nurses to that in female nurses with routine daytime shifts.

Methods

A total of 19 nurses without lower urinary tract symptoms who worked rotational shifts for an average duration of 2 years were recruited. A voiding diary was kept for 9 consecutive days, and the overactive bladder symptom score (OABSS) questionnaire was completed three times, starting 3 days before their night duties until 3 days after completion of their night duties. For comparison, seven nurses with regular shifts completed a 3-day voiding diary and the OABSS questionnaire.

Results

Female nurses working rotational shifts had lower overall urine production and had decreased urination frequency and nocturia than female nurses working regular shifts, even when the nurses who worked rotational shifts had a regular night's sleep for at least 7 days. Upon reinitiation of night duty, overall urine production increased significantly, with no significant changes in urgency and frequency. When these nurses returned to daytime duty, the volume of urine decreased but nocturnal urine production remained high, and the incidence of nocturia also increased significantly. However, the effects on OABSS score were not significant under the study design used.

Conclusions

Long-term rotational shifts resulted in adaptive changes such as decreased urine production and frequency in healthy, young female nurses. In addition, their micturition patterns were significantly affected by abrupt changes in their work schedules. Although working in shifts did not increase urgency or frequency of urination in healthy, young female nurses working rotational shifts for an average 2 years, large-scale studies are needed to systematically analyze the influence of shift work timings on micturition in humans.

Presence of multiple peripheral circadian oscillators in the tissues controlling voiding function in mice

Circadian clocks are the endogenous oscillators that harmonize a variety of physiological processes within the body. Although many urinary functions exhibit clear daily or circadian variation in diurnal humans and nocturnal rodents, the precise mechanisms of these variations are as yet unclear. In the present study, we demonstrate that Per2 promoter activity clearly oscillates in neonate and adult bladders cultured ex vivo from Per2::Luc knock-in mice. In subsequent experiments, we show that multiple local oscillators are operating in all the bladder tissues (detrusor, sphincter and urothelim) and the lumbar spinal cord (L4–5) but not in the pontine micturition center or the ventrolateral periaqueductal gray of the brain. Accordingly, the water intake and urine volume exhibited daily and circadian variations in young adult wild-type mice but not in Per1^−/−Per2^−/− mice, suggesting a functional clock-dependent nature of the micturition rhythm. Particularly in PDK mice, the water intake and urinary excretion displayed an arrhythmic pattern under constant darkness, and the amount of water consumed and excreted significantly increased compared with those of WT mice. These results suggest that local circadian clocks reside in three types of bladder tissue and the lumbar spinal cord and may have important roles in the circadian control of micturition function.

Temporal dynamics of antibiotics in wastewater treatment plant influent

A yearlong field experimental campaign was conducted to reveal time scales over which antibiotic fluxes vary in the influent of a wastewater treatment plant (WTP). In particular, sampling was carried out to ascertain the amplitudes of monthly, daily and hourly fluctuations of several antibiotics. A total of 180 samples was collected at the entrance of a WTP in Lausanne, Switzerland. Sample concentrations were multiplied by flow rate to obtain monthly, daily and hourly mass fluxes of six antibiotics (trimethoprim, norfloxacin, ciprofloxacin, ofloxacin, clindamycin and metronidazole). Seasonality in mass fluxes was observed for all substances, with maximum values in winter being up to an order of magnitude higher than in summer. The hourly measurements of the mass flux of antibiotics were found to have a period of 12h. This was due to peaks in toilet use in the morning and early evening. In particular, the morning peak in flushing coincided with high concentrations (and hence high mass fluxes) due to overnight accumulation of substances in urine. However, little variation was observed in the average daily flux. Consequently, fluctuations in mass fluxes of antibiotics were mainly evident at the monthly and hourly time scales, with little variation on the day-week time scale. These results can aid in optimizing removal strategies and future sampling campaigns focused on antibiotics in wastewater.

Circadian regulation of low density lipoprotein receptor promoter activity by CLOCK/BMAL1, Hes1 and Hes6

Low density lipoprotein receptor (LDLR) plays an important role in the cholesterol homeostasis. We examined the possible circadian regulation of LDLR and mechanism(s) underlying it. In mice, blood glucose and plasma triglyceride, total and high density lipoprotein cholesterol varied distinctively throughout a day. In addition, LDLR mRNA oscillated in the liver in a functional clock-dependent manner. Accordingly, analysis of human LDLR promoter sequence revealed three putative E-boxes, raising the possible regulation of LDLR expression by E-box-binding transcription factors. To test this possibility, human LDLR promoter reporter constructs were transfected into HepG2 cells and the effects of CLOCK/BMAL1, Hes1, and Hes6 expression were analyzed. It was found that positive circadian transcription factor complex CLOCK/BMAL1 upregulated human LDLR promoter activity in a serum-independent manner, while Hes family members Hes1 and Hes6 downregulated it only under serum-depleted conditions. Both effects were mapped to proximal promoter region of human LDLR, where mutation or deletion of well-known sterol regulatory element (SRE) abolished only the repressive effect of Hes1. Interestingly, hes6 and hes1 mRNA oscillated in an anti-phasic manner in the wild-type but not in the per1-/-per2 -/- mouse. Comparative analysis of mouse, rat and human hes6 genes revealed that three E-boxes are conserved among three species. Transfection and site-directed mutagenesis studies with hes6 reporter constructs confirmed that the third E-box in the exon IV is functionally induced by CLOCK/BMAL1. Taken together, these results suggest that LDLR expression is under circadian control involving CLOCK/BMAL1 and Hes family members Hes1 and Hes6.