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Journal of Biophotonics Dec 2019Visible light synchronizes the human biological clock in the suprachiasmatic nuclei of the hypothalamus to the solar 24-hour cycle. Short wavelengths, perceived as blue... (Review)
Review
Visible light synchronizes the human biological clock in the suprachiasmatic nuclei of the hypothalamus to the solar 24-hour cycle. Short wavelengths, perceived as blue color, are the strongest synchronizing agent for the circadian system that keeps most biological and psychological rhythms internally synchronized. Circadian rhythm is important for optimum function of organisms and circadian sleep-wake disruptions or chronic misalignment often may lead to psychiatric and neurodegenerative illness. The beneficial effect on circadian synchronization, sleep quality, mood, and cognitive performance depends not only on the light spectral composition but also on the timing of exposure and its intensity. Exposure to blue light during the day is important to suppress melatonin secretion, the hormone that is produced by the pineal gland and plays crucial role in circadian rhythm entrainment. While the exposure to blue is important for keeping organism's wellbeing, alertness, and cognitive performance during the day, chronic exposure to low-intensity blue light directly before bedtime, may have serious implications on sleep quality, circadian phase and cycle durations. This rises inevitably the need for solutions to improve wellbeing, alertness, and cognitive performance in today's modern society where exposure to blue light emitting devices is ever increasing.
Topics: Aging; Behavior; Circadian Rhythm; Color; Humans; Light; Retina
PubMed: 31433569
DOI: 10.1002/jbio.201900102 -
Cell Jul 2022Cell types are the basic functional units of an organism. Cell types exhibit diverse phenotypic properties at multiple levels, making them challenging to define,... (Review)
Review
Cell types are the basic functional units of an organism. Cell types exhibit diverse phenotypic properties at multiple levels, making them challenging to define, categorize, and understand. This review provides an overview of the basic principles of cell types rooted in evolution and development and discusses approaches to characterize and classify cell types and investigate how they contribute to the organism's function, using the mammalian brain as a primary example. I propose a roadmap toward a conceptual framework and knowledge base of cell types that will enable a deeper understanding of the dynamic changes of cellular function under healthy and diseased conditions.
Topics: Animals; Brain; Humans; Mammals; Single-Cell Analysis
PubMed: 35868277
DOI: 10.1016/j.cell.2022.06.031 -
Redox Report : Communications in Free... Dec 2022Mitochondria are the main source of reactive oxygen species (ROS) in cells. Early studies have shown that mitochondrial reactive oxygen species (mROS) are related to the... (Review)
Review
Mitochondria are the main source of reactive oxygen species (ROS) in cells. Early studies have shown that mitochondrial reactive oxygen species (mROS) are related to the occurrence and adverse outcomes of many diseases, and are thus regarded as an important risk factor that threaten human health. Recently, increasing evidence has shown that mROS are very important for an organism's homeostasis. mROS can regulate a variety of signaling pathways and activate the adaptation and protection behaviors of an organism under stress. In addition, mROS also regulate important physiological processes, such as cell proliferation, differentiation, aging, and apoptosis. Herein, we review the mechanisms of production, transformation, and clearance of mROS and their biological roles in different physiological processes.
Topics: Apoptosis; Homeostasis; Humans; Mitochondria; Oxidative Stress; Reactive Oxygen Species
PubMed: 35213291
DOI: 10.1080/13510002.2022.2046423 -
Nutrients Jun 2020Nutrition of preterm infants has a crucial role in the promotion of organ's optimal growth and development [...].
Nutrition of preterm infants has a crucial role in the promotion of organ's optimal growth and development [...].
Topics: Humans; Infant Nutritional Physiological Phenomena; Infant, Newborn; Infant, Premature; Milk, Human; Nutritional Status; Nutritional Support
PubMed: 32580318
DOI: 10.3390/nu12061857 -
Experimental Gerontology Apr 2020Aging is characterized by a progressive decline in the normal physiological functions of an organism, ultimately leading to mortality. Nicotinamide adenine dinucleotide... (Review)
Review
Aging is characterized by a progressive decline in the normal physiological functions of an organism, ultimately leading to mortality. Nicotinamide adenine dinucleotide (NAD) is an essential cofactor that plays a critical role in mitochondrial energy production as well as many enzymatic redox reactions. Age-associated decline in NAD is implicated as a driving factor in several categories of age-associated disease, including metabolic and neurodegenerative disease, as well as deficiency in the mechanisms of cellular defense against oxidative stress. The kynurenine metabolic pathway is the sole de novo NAD biosynthetic pathway, generating NAD from ingested tryptophan. Altered kynurenine pathway activity is associated with both aging and a variety of age-associated diseases. Kynurenine pathway interventions can extend lifespan in both fruit flies and nematodes, and altered NAD metabolism represents one potential mediating mechanism. Recent studies demonstrate that supplementation with NAD or NAD-precursors increase longevity and promote healthy aging in fruit flies, nematodes, and mice. NAD levels and the intrinsic relationship to mitochondrial function have been widely studied in the context of aging. Mitochondrial function and dynamics have both been implicated in longevity determination in a range of organisms from yeast to humans, at least in part due to their intimate link to regulating an organism's cellular energy economy and capacity to resist oxidative stress. Recent findings support the idea that complex communication between the mitochondria and the nucleus orchestrates a series of events and stress responses involving mitophagy, mitochondrial number, mitochondrial unfolded protein response (UPR), and mitochondria fission and fusion events. In this review, we discuss how mitochondrial morphological changes and dynamics operate during aging, and how altered metabolism of tryptophan to NAD through the kynurenine pathway interacts with these processes.
Topics: Aging; Animals; Brain; Humans; Kynurenine; Longevity; Metabolic Networks and Pathways; Mice; Mitochondria; Mitophagy; NAD; Neurodegenerative Diseases; Oxidation-Reduction; Oxidative Stress; Tryptophan
PubMed: 31954874
DOI: 10.1016/j.exger.2020.110841