Exposure to Artificial Light at Night Alters Ultradian Rhythms in Endothelial Function.

Endogenous biological timing mechanisms are fundamental aspects of living cells, tissues, and organisms. Virtually every aspect of physiology and behavior is mediated by self-sustaining circadian clocks, which depend on light to synchronize with the external daily environment. However, exposure to artificial light at night (ALAN) can impair temporal adaptations, and affect health and disease.

Female ethanolamine phosphate phospholyase knockout mice resisted high-fat diet-induced obesity with attenuated hepatic cholesterol deposition.

Ethanolamine phosphate phospholyase (ETNPPL) is an enzyme that irreversibly degrades phosphoethanolamine (p-ETN), an intermediate in the Kennedy pathway of phosphatidylethanolamine (PE) synthesis. Whole body knockout mice were fed a high-fat diet (HFD) containing 45% kcal fat for 10 wk. female mice were resistant to HFD-induced obesity and had decreased liver weight compared with mice.

Effects of air and light pollution on brain and behavioral function: Potential synergy.

The growing global prevalence of artificial light at night (ALAN) and air pollution has raised concerns regarding their effects on human health. Several epidemiological, preclinical, and clinical studies suggest that both ALAN and air pollution can independently contribute to adverse brain health outcomes, including cognitive decline, increased risk of neurodegenerative diseases, and behavioral disorders. Air pollutants can enter the bloodstream and reach the brain, leading to potential neuropathology.

Circadian influences on central nervous system barriers and the glymphatic system.

The central nervous system (CNS), comprising the brain and spinal cord, is fortified by complex barriers that protect the underlying organs and maintain homeostasis. The importance of proper fortification and homeostatic regulation provided by these systems has broad implications for many physiological processes and several pathological conditions are associated with their disruption. Recent studies support the notion that CNS barriers and fluids are regulated by circadian rhythms.

The emerging role of ethanolamine phosphate phospholyase in regulating hepatic phosphatidylethanolamine and plasma lipoprotein metabolism in mice.

Ethanolamine phosphate phospholyase (ETNPPL) is an enzyme that irreversibly degrades phospho-ethanolamine (p-ETN), an intermediate in the Kennedy pathway of phosphatidylethanolamine (PE) biosynthesis. PE is the second most abundant phospholipid in mammalian membranes. Disturbance of hepatic phospholipid homeostasis has been linked to the development of metabolic dysfunction-associated steatotic liver disease (MASLD).

Disrupted Circadian Rhythms and Substance Use Disorders: A Narrative Review.

Substance use disorder is a major global health concern, with a high prevalence among adolescents and young adults. The most common substances of abuse include alcohol, marijuana, cocaine, nicotine, and opiates. Evidence suggests that a mismatch between contemporary lifestyle and environmental demands leads to disrupted circadian rhythms that impair optimal physiological and behavioral function, which can increase the vulnerability to develop substance use disorder and related problems.

Chronic phase advances reduces recognition memory and increases vascular cognitive dementia-like impairments in aged mice.

Disrupted or atypical light-dark cycles disrupts synchronization of endogenous circadian clocks to the external environment; extensive circadian rhythm desynchrony promotes adverse health outcomes. Previous studies suggest that disrupted circadian rhythms promote neuroinflammation and neuronal damage post-ischemia in otherwise healthy mice, however, few studies to date have evaluated these health risks with aging. Because most strokes occur in aged individuals, we sought to identify whether, in addition to being a risk factor for poor ischemic outcome, circadian rhythm disruption can increase risk for vascular cognitive impairment and dementia (VCID).

Recommendations for measuring and standardizing light for laboratory mammals to improve welfare and reproducibility in animal research.

Light enables vision and exerts widespread effects on physiology and behavior, including regulating circadian rhythms, sleep, hormone synthesis, affective state, and cognitive processes. Appropriate lighting in animal facilities may support welfare and ensure that animals enter experiments in an appropriate physiological and behavioral state. Furthermore, proper consideration of light during experimentation is important both when it is explicitly employed as an independent variable and as a general feature of the environment.

Time of day bias for biological sampling in studies of mammary cancer.

Despite its demonstrated biological significance, time of day is a broadly overlooked biological variable in preclinical and clinical studies. How time of day affects the influence of peripheral tumors on central (brain) function remains unspecified. Thus, we tested the hypothesis that peripheral mammary cancer tumors alter the transcriptome of immune responses in the brain and that these responses vary based on time of day; we predicted that time of day sampling bias would alter the interpretation of the results.

Social enrichment alters the response of brain leukocytes to chemotherapy and tumor development in aged mice.

Aging is a risk factor for the development of breast cancer. Foundational science studies have supported associations among neuroinflammation, breast cancer, and chemotherapy, but to date, these associations are based on studies using young adult rodents. The current study examined the neuroinflammatory effects of chemotherapy in aged, tumor-naïve and tumor-bearing mice with or without social enrichment.

Chronotherapeutics for Solid Tumors.

Circadian rhythms are internal manifestations of the 24-h solar day that allow for synchronization of biological and behavioral processes to the external solar day. This precise regulation of physiology and behavior improves adaptive function and survival. Chronotherapy takes advantage of circadian rhythms in physiological processes to optimize the timing of drug administration to achieve maximal therapeutic efficacy and minimize negative side effects.

Therapeutic Aspects of Circadian Rhythms.

Circadian rhythms are ubiquitous endogenous rhythms with a period of approximately twenty-four hours [...

Acute exposure to artificial light at night alters hippocampal vascular structure in mice.

The structure and function of the cardiovascular system are modulated across the day by circadian rhythms, making this system susceptible to circadian rhythm disruption. Recent evidence demonstrated that short-term exposure to a pervasive circadian rhythm disruptor, artificial light at night (ALAN), increased inflammation and altered angiogenic transcripts in the hippocampi of mice. Here, we examined the effects of four nights of ALAN exposure on mouse hippocampal vascular networks.

The role of daylight exposure on body mass in male mice.

Physiology and behavior are synchronized to the external environment by endogenous circadian rhythms that are set to precisely 24 h by exposure to bright light early in the day. Exposure to artificial light outside of the typical solar day, such as during the night, may impair aspects of physiology and behavior in human and non-human animals. Both the intensity and the wavelength of light are important in mediating these effects.

The disruptive relationship among circadian rhythms, pain, and opioids.

Pain behavior and the systems that mediate opioid analgesia and opioid reward processing display circadian rhythms. Moreover, the pain system and opioid processing systems, including the mesolimbic reward circuitry, reciprocally interact with the circadian system. Recent work has demonstrated the disruptive relationship among these three systems.

Circadian Rhythms Disrupted by Light at Night and Mistimed Food Intake Alter Hormonal Rhythms and Metabolism.

Availability of artificial light and light-emitting devices have altered human temporal life, allowing 24-hour healthcare, commerce and production, and expanding social life around the clock. However, physiology and behavior that evolved in the context of 24 h solar days are frequently perturbed by exposure to artificial light at night. This is particularly salient in the context of circadian rhythms, the result of endogenous biological clocks with a rhythm of ~24 h.

Chronic exposure to dim light at night disrupts cell-mediated immune response and decreases longevity in aged female mice.

Circadian rhythms are endogenous biological cycles that regulate physiology and behavior for optimal adaptive function and survival; they are synchronized to precisely 24 hours by daily light exposure. Disruption of the daily light-dark (LD) cycle by exposure to artificial light at night (ALAN) dysregulates core clock genes and biological function. Exposure to ALAN has been associated with increased health risks in humans, and elderly individuals are at elevated risk for poor outcome from disease and often experience elevated exposure to ALAN due to increased care requirements.

Machine learning and deep learning frameworks for the automated analysis of pain and opioid withdrawal behaviors.

The automation of behavioral tracking and analysis in preclinical research can serve to advance the rate of research outcomes, increase experimental scalability, and challenge the scientific reproducibility crisis. Recent advances in the efficiency, accuracy, and accessibility of deep learning (DL) and machine learning (ML) frameworks are enabling this automation. As the ongoing opioid epidemic continues to worsen alongside increasing rates of chronic pain, there are ever-growing needs to understand opioid use disorders (OUDs) and identify non-opioid therapeutic options for pain.

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.

The Ventral Tegmental Area and Nucleus Accumbens as Circadian Oscillators: Implications for Drug Abuse and Substance Use Disorders.

Circadian rhythms convergently evolved to allow for optimal synchronization of individuals' physiological and behavioral processes with the Earth's 24-h periodic cycling of environmental light and temperature. Whereas the suprachiasmatic nucleus (SCN) is considered the primary pacemaker of the mammalian circadian system, many extra-SCN oscillatory brain regions have been identified to not only exhibit sustainable rhythms in circadian molecular clock function, but also rhythms in overall region activity/function and mediated behaviors. In this review, we present the most recent evidence for the ventral tegmental area (VTA) and nucleus accumbens (NAc) to serve as extra-SCN oscillators and highlight studies that illustrate the functional significance of the VTA's and NAc's inherent circadian properties as they relate to reward-processing, drug abuse, and vulnerability to develop substance use disorders (SUDs).

Open-source analysis and visualization of segmented vasculature datasets with VesselVio.

Vascular networks are fundamental components of biological systems. Quantitative analysis and observation of the features of these networks can improve our understanding of their roles in health and disease. Recent advancements in imaging technologies have enabled the generation of large-scale vasculature datasets, but barriers to analyzing these datasets remain.

Effects of light pollution on photoperiod-driven seasonality.

Changes to photoperiod (day length) occur in anticipation of seasonal environmental changes, altering physiology and behavior to maximize fitness. In order for photoperiod to be useful as a predictive factor of temperature or food availability, day and night must be distinct. The increasing prevalence of exposure to artificial light at night (ALAN) in both field and laboratory settings disrupts photoperiodic time measurement and may block development of appropriate seasonal adaptations.