Author Interviews, Circadian Rhythm, Diabetes, Exercise - Fitness, Hepatitis - Liver Disease / 01.11.2022

MedicalResearch.com Interview with: Jeroen van der Velde, PhD Leiden University Medical Center Dept. Clinical Epidemiology, C7-102 Leiden, The Netherlands MedicalResearch.com: What is the background for this study? Response: We hypothesized that, in addition to the amount of physical activity, the pattern in which physical activity is accumulated over the day is relevant for metabolic health. Several studies previously showed beneficial effects of interrupting sedentary periods with short periods of activity (breaks in sedentary time) on glucose control. In addition, very recently it has been argued that the timing of physical activity during the day may be relevant for metabolic health. This was mainly shown in animal studies and intervention studies with supervised high intensity exercise training in men with impaired glucose control or type 2 diabetes. If timing of physical activity matters in a ‘free-living’ setting in the general population is largely unknown. Therefore, our aim was to investigate associations of timing of physical activity and breaks in sedentary time with liver fat content and insulin resistance in a middle-aged population. (more…)
Author Interviews, Brigham & Women's - Harvard, Circadian Rhythm, Diabetes, Occupational Health, Science, Weight Research / 06.12.2021

MedicalResearch.com Interview with: Sarah L. Chellappa, MD PhD Medical Chronobiology Program Division of Sleep and Circadian Disorders Departments of Medicine and Neurology Brigham and Women’s Hospital Division of Sleep Medicine, Harvard Medical School Boston, MA Department of Nuclear Medicine Faculty of Medicine and University Hospital Cologne University of Cologne, Cologne, Germany. Frank A.J.L. Scheer, M.Sc., Ph.D. Professor of Medicine. Medical Chronobiology Program Division of Sleep and Circadian Disorders Departments of Medicine and Neurology Brigham and Women’s Hospital Division of Sleep Medicine, Harvard Medical School Boston, MA MedicalResearch.com: What is the background for this study? Would you explain the difference between the central circadian ‘clock’ and endogenous circadian glucose rhythms?  Response: Night work increases diabetes risk. This increased risk is not fully explained by differences in lifestyle, family history, and/or socioeconomic status, thus other mechanisms are likely involved. Laboratory studies in humans have shown glucose intolerance in both non-shift workers and shift workers exposed to simulated night work. Animal experimental data suggests that this may be in part due to a misalignment between central and peripheral rhythms. Central circadian rhythms (e.g., body temperature) are primarily modulated by the central circadian “clock”, which is located in the brain’s suprachiasmatic nucleus and is responsible for synchronizing our physiology and behavior with the 24-hour cycle. Peripheral rhythms, including endogenous circadian glucose rhythms, are likely modulated by peripheral “clocks” across the body that play an integral role in modulating the circadian expression of physiology, including metabolic functions. These central and peripheral clocks share a common molecular mechanism underlying their circadian rhythm generating capacity, including transcription-translation feedback loops of circadian “clock” genes.  (more…)
Asthma, Author Interviews, Brigham & Women's - Harvard, Circadian Rhythm, Occupational Health, PNAS, Pulmonary Disease, Sleep Disorders / 11.09.2021

MedicalResearch.com Interview with: Frank Scheer, PhD, MSc Professor and Director of the Medical Chronobiology Program Division of Sleep and Circadian Disorders Brigham and Women’s Hospital Steve Shea, PhD Professor and Director Oregon Institute of Occupational Health Sciences MedicalResearch.com: What is the background for this study? Response: For hundreds of years, people have observed that asthma severity often worsens in the nighttime. As many as 75 percent of people with asthma—20 million people in the U.S.—report experiencing worsening asthma severity at night. One longstanding question has been to what degree the body’s internal circadian clock—as opposed to behaviors, such as sleep and physical activities—contributes to worsening of asthma severity. Our research used long term intensive monitoring throughout two circadian protocols in dim light and without time cues to carefully isolate the influence of the circadian system from the other factors that are behavioral and environmental, including sleep. (more…)
Author Interviews, Circadian Rhythm, Heart Disease, Occupational Health, Sleep Disorders / 27.04.2021

Circadian misalignment is associated with a high cardiovascular risk among shift workers: MedicalResearch.com Interview with: Sara Gamboa Madeira Medical Doctor - General & Family Physician PhD Student - EnviHealth&Co - Faculty of Medicine Lisbon University MedicalResearch.com: What is the background for this study? Response: One in every five employees work in shifts across Europe1. Shift work have been associated with an increased risk for several cardiovascular diseases2 and three main mechanism have been proposed: unhealthy behaviours, disturbed sleep, and circadian misalignment. This study focused on the role of circadian misalignment, which we assessed via social jetlag. Social jetlag is calculated using the Munich Chronotype Questionnaire3 by the difference between sleep behaviour on free-days (mainly driven by the individual “biological clock”, also called chronotype) and sleep behaviour on workdays (mainly drive by the “social clock”, namely work schedules). Chronotype is an individual feature which ranges from early/morning people to late/evening people (from proverbial lark to owls), with the majority of the population falling in between as a Gaussian distribution. Therefore higher levels of social jetlag mean a greater mismatch between what your biological clock need (e.g. go to sleep at 9pm) and what your social obligations impose on you (e.g. work until midnight). (more…)
Author Interviews, BMJ, Circadian Rhythm, JAMA, Occupational Health / 27.02.2021

MedicalResearch.com Interview with: Dr Tapio Räihä Center for Life Course Health Research University of Oulu, Oulu, Finland MedicalResearch.com: What is the background for this study? sleep-work-occupational-chronotypeResponse: In ageing societies, understanding risk factors for pre-term disability pensions and poor work ability is an important research priority. We studied whether individual-level chronotype could contribute to these.  Previous research has shown that evening chronotypes (E-types) have poorer health compared with morning chronotypes (M-types), and that E-types may have difficulties to function during standard morning working hours. This study was the first population-level study with register linkage to find out whether eveningness would be associated with poor work ability and disability pensions, too. We surveyed chronotype (with the Morningness–Eveningness Questionnaire) among 5831 non-retired Finns born in 1966 when they were at age 46 years, and compared it with their current perceived work ability. We then followed the emergence of new registered disability pensions during the next 4 years. Multivariate logistic and Cox regression analyses of the associations between chronotype and the outcomes were separately adjusted for sleep, health and behaviours, sociodemographic and economic factors, or working times  (more…)
Author Interviews, Circadian Rhythm, Exercise - Fitness / 11.12.2020

MedicalResearch.com Interview with: Andrew W. McHill, PhD Research Assistant Professor Oregon Institute of Occupational Health Sciences Oregon Health & Science University, Portland OR Portland, OR 97239 MedicalResearch.com: What is the background for this study? Response: It has long been known that there is a home court advantage in sports, whether it be due to the home fans cheering, playing within familiar settings, or travel of the opposing team. However, the contribution of travel to home-court advantage could never be fully teased apart due to all the confounds of the other aspects of playing at home. In March, the National Basketball Association had to pause their season due to COVID-19 concerns, only to start again several months later with the top 22 teams playing in a “bubble” environment where no teams were required to travel. This created a ‘natural experiment’ wherein we could test the impact of travel on winning and performance before the COVID-19 shutdown with games played in the bubble environment with no travel. (more…)
AHA Journals, Author Interviews, Blood Pressure - Hypertension, Circadian Rhythm / 05.11.2020

MedicalResearch.com Interview with: Kazuomi Kario, MD, PhD, FACP, FACC, FAHA, FESC, FJCS Professor, Chairman Division of Cardiovascular Medicine, Department of Medicine, Jichi Medical University School of Medicine (JMU) JMU Center of Excellence, Cardiovascular Research and Development (JCARD) Hypertension Cardiovascular Outcome Prevention and Evidence in Asia (HOPE Asia) Network Shimotsuke, Tochigi, 329-0498, JAPAN MedicalResearch.com: What is the background for this study? Response: To date, it remains unclear whether disrupted blood pressure (BP) circadian rhythm is associated with adverse outcomes independent of nighttime BP. The JAMP study includes 6359 outpatient population who had ambulatory BP monitoring to evaluate the association between both nocturnal hypertension and nighttime BP dipping patterns and the occurrence of cardiovascular events in patients with hypertension. (more…)
Author Interviews, Circadian Rhythm, COVID -19 Coronavirus, Sleep Disorders / 15.06.2020

MedicalResearch.com Interview with: Dr. Christine Blume PhD Centre for Chronobiology Psychiatric Hospital of the University of Basel Transfaculty Research Platform Molecular and Cognitive Neurosciences Basel MedicalResearch.com: What is the background for this study? Response: In modern societies, human rest-activity rhythms and sleep are between the often-conflicting poles of external social time (e.g., work hours and leisure activities) and an individual’s internal biological time. This can lead to so-called “social jetlag”, which has repeatedly been associated with detrimental health effects. With the restrictions to control the pandemic, social timing relaxed as people many started working from home and public life came to a standstill. In an online survey with 435 respondents, we investigated the effects of the phase with the strictest COVID-19 restrictions on the relationship between social and biological rhythms as well as sleep during a six-week period (mid-March until end of April 2020) in three European societies (Austria, Germany, Switzerland). (more…)
Accidents & Violence, Author Interviews, Circadian Rhythm / 03.02.2020

MedicalResearch.com Interview with: Josef Fritz, Ph.D. PostDoctoral Fellow Circadian and Sleep Epidemiology Laboratory Department of Integrative Physiology University of Colorado Boulder MedicalResearch.com: What is the background for this study? Response: Daylight Saving Time (DST), the practice of setting clocks forward by an hour during the summer months and an hour back again during the winter months, is currently given a lot of attention, also because of world-wide discussions whether DST should be abolished, extended, or kept year-around. Since its introduction, mainly with the intention to reduce energy consumption, the spring DST transition has been associated with various adverse outcomes within the first few days after the transition, including an increased risk of myocardial infarctions, strokes, and workplace accidents. When we reviewed the evidence linking DST to traffic accident risk, however, results were not that clear-cut. We thus decided to take a closer look, based on one of the most extensive datasets so far, with 22 years of fatal traffic accident recordings across the US. We also aimed at decomposing the potential overall effect of Daylight Saving Time on traffic accident risk, given that both environmental illumination levels, and geographical factors such as position in time zone, may play a role in modulating fatal traffic accident risk associated with DST, but explicit and concurrent examination of these factors has so far been lacking. (more…)
Author Interviews, Circadian Rhythm, Gastrointestinal Disease, Genetic Research, Weight Research / 13.10.2019

MedicalResearch.com Interview with: Marco Colonna, MD Robert Rock Belliveau MD Professor Pathology & Immunology Washington University School of Medicine Qianli Wang MD-PhD Student MSTP student Washington University School of Medicine MedicalResearch.com: What is the background for this study? Response: Many aspects of the mammalian digestive system including gut motility, nutrient absorption, and microbiota follow a daily rhythm. This circadian rhythm is generated by the cyclic expressions of molecular clock genes thought to be present in most cells. Group 3 innate lymphoid cells (ILC3) are lymphocytes residing in the intestinal mucosa that respond rapidly to activation in both homeostatic and inflammatory settings. Namely, ILC3s help maintain the mucosal barrier, regulate epithelial lipid transport, and protect against bacterial enteric infections. As tissue resident cells within the highly dynamic and rhythmic environment of the intestine, it may be advantageous for ILC3s to also be synchronized with the circadian rhythm.  (more…)
Author Interviews, Circadian Rhythm, Heart Disease, JACC / 11.08.2019

MedicalResearch.com Interview with: Dr. Alan Cheng, MD MBA Vice President at Medtronic Clinical Research and Therapy Development, Cardiac Rhythm Management Medtronic, Minnesota 55112  MedicalResearch.com: What is the background for this study? What are the main findings? Response: Ventricular arrhythmias can be life threatening among patients with certain types of heart disease. While implantable cardioverter defibrillators (ICDs) have become the primary means in managing these events, we still don’t fully understand when ventricular arrhythmias occur and whether they are just random events that occur at any time of the day. We pooled patient-level data from 6 prospective studies of ICD recipients and leveraged the continuous monitoring features of the ICD to understand when ventricular arrhythmias occur. Across almost 4000 patients with almost 2 years average follow up from the time of implant, we saw that ventricular arrhythmias aren’t randomly distributed throughout the day. In fact, there is a predilection for these events to occur during normal waking hours as compared to the times of the day when most patients are asleep. Additionally, we found that across the year, the spring season had higher rates of arrhythmia occurrence when compared to summer. We didn’t observe any differences in arrhythmia occurrence by the days of the week or months of the year. This analysis is not the first to explore this question but it is the largest to date.  (more…)
Aging, Author Interviews, Circadian Rhythm / 21.03.2019

MedicalResearch.com Interview with: Adrian Bejan PhD ( MIT 1971, 1972, 1975 ) J.A. Jones Distinguished Professor Duke University MedicalResearch.com: What is the background for this study? What are the main findings? Response: Among the most common human perceptions is that time passes faster as an individual becomes older. The days become shorter, and so do the years. We all have stories of this kind, from the long days of childhood and the never-ending class hours in elementary school, to days, months and years that now pass in a blur. Why does it feel that the time passes faster as we get older? What is the physical basis for the impression that some days are slower than others? Why do we tend to focus on the unusual (the surprise), not on the ever present? This new article unveils the physics basis for these common observations. The reason is that the measurable ‘clock time’ is not the same as the time perceived by the human mind. The ‘mind time’ is a sequence of images, i.e. reflections of nature that are fed by stimuli from sensory organs. The rate at which changes in mental images are perceived decreases with age, because of several physical features that change with age: saccades frequency, body size, pathways degradation, etc. The misalignment between mental-image time and clock time serves to unite the voluminous observations of this phenomenon in the literature with the constructal law of evolution everywhere, as physics. (more…)
Author Interviews, Circadian Rhythm, Gender Differences / 18.01.2019

MedicalResearch.com Interview with: Lauren Douma, Ph.D. Postdoctoral Fellow University of Florida Department of Medicine Division of Nephrology, Hypertension, and Renal Transplantation Gainesville, FL 32610 MedicalResearch.com: What is the background for this study? What are the main findings?  Response: Our internal circadian clock not only controls our sleep/wake cycle, but also many other physiological functions including rhythms in body temperature, heart rate, and blood pressure. During the day when we are active our blood pressure peaks and at night when we are asleep our blood pressure dips. Certain individuals do not experience this dip in their blood pressure at night and are referred to as non-dippers. Non-dippers have an increased risk for heart and kidney disease. Previously, our lab has shown that if we knock out a core circadian clock gene (PER1) in male mice, they develop non-dipping hypertension on a treatment that mimics salt-sensitive hypertension. In the current study, we examined the effect of knocking out this circadian clock gene in female mice. We found that female mice without the PER1 gene do not develop the non-dipping hypertension that the males develop. Female mice without PER1 maintain their circadian rhythms of blood pressure, including the dip in their blood pressure at night even with the same treatment that the males received to mimic salt-sensitive hypertension. (more…)
Author Interviews, Circadian Rhythm / 28.11.2018

MedicalResearch.com Interview with: Yujiro Yamanaka, Ph.D. Associate Professor Hokkaido University Graduate School of Education Sapporo, Japan  MedicalResearch.com: What is the background for this study? Response: My laboratory has focused on the human circadian rhythms in particularly investigating the time of day effect of non-photic cues especially physical exercise and psychological stressor on circadian rhythms. In mammals including humans, the central circadian pacemaker is located in the suprachiasmatic nucleus (SCN) in the brain hypothalamus. The SCN entrains to an external light-dark cycle and generates endogenous 24 h rhythmicity in body function. The hypothalamic-pituitary-adrenal (HPA) axis is our major stress response system. We can assess the response of HPA axis to psychological stress event by measuring the level of glucocorticoid hormone, cortisol in saliva. The cortisol shows clear circadian rhythm with higher levels in the morning and lower levels in the evening. This rhythm is generated by the SCN circadian pacemaker. Previous study (Kudielka et al. Psychoneuroendocrinology 2004) could demonstrate that the cortisol stress level is significantly elevated by acute psychological stress event in the morning (9 a.m. to 10 a.m.) and afternoon (3 p.m. to 4 p.m.). However, there are no study examining the effect of evening psychological stress event on the HPA axis activity. Thus, our new study focused on examining whether the HPA axis differentially responses to morning and evening stress event in healthy subjects. (more…)
Author Interviews, Circadian Rhythm, Heart Disease / 11.11.2018

MedicalResearch.com Interview with: sunset copyright American Heart AssociationJay Chudow, M.D. Montefiore Medical Center Bronx, New York MedicalResearch.com: What is the background for this study? What are the main findings?
  • Others found associations between daylight saving time transitions and sleep duration, sleep quality, workplace injuries and traffic accidents. Regarding cardiovascular health, studies in Europe and the United States have found an increased incidence of acute myocardial infarction and ischemic stroke in the days following daylight saving time transitions.
  • Our study found a significant increase in admissions for atrial fibrillation following the daylight saving time spring transition compared to the yearly average (average of 3.13 vs 2.56 admissions per day over the Monday to Thursday period). No significant difference was found following the autumn transition.
  • These findings add atrial fibrillation as a known condition associated with daylight saving time transitions. It adds to the knowledge base of negative health consequences of daylight saving time. 
(more…)
Author Interviews, Cancer Research, Circadian Rhythm, Nutrition / 19.07.2018

MedicalResearch.com Interview with: “Christmas Roast and Ham Dinner. Had Tamales for Christmas Eve and Christmas morning. #Roast #Ham #ChristmasDinner #Christmas #Champagne #Dinner #Foodstagram” by Yvonne Esperanza is licensed under CC BY 2.0Manolis Kogevinas, MD, PhD Research Professor NCDs & Environment Group Barcelona Institute for Global Health (ISGlobal) - Campus MAR Barcelona Biomedical Research Park (PRBB) (office 194) Barcelona, Spain MedicalResearch.com: What is the background for this study? What are the main findings? Response: We did the study for two main reasons. (i) breast and to a less extent prostate cancer are the cancers that have been associated with night shift work and resulting circadian disruption (disruption of the natural day-light cycle); (ii) experimental studies in animals indicate that timing of diet is important. For example, giving an hypercaloric diet to mice during the day results in obesity, while giving the same diet during the night does not. Mice are nocturnal animals and this means that there normal eating time is the night when they can metabolise what they eat. So, would something similar affect humans? When we eat in late hours at a time when “normally” (normally in the sense of evolution) we would be resting. In this study we show that adherence to a more diurnal eating pattern and specifically an early supper and a long interval between last meal and sleep are associated with a lower breast and prostate cancer risk. Specifically having super before 9pm and having an interval of 2 hours between the last big meal and sleep, were both associated with an approximately 20% prevention of breast and prostate cancer) compared to those who have supper after 10pm or those who eat and then sleep very close after supper. Also, the strongest protection was found in “morning types” as compared to “evening types”. Morning types are expected to function worse than evening types in late evening so late suppers may have more adverse effects on them. (more…)
Author Interviews, Circadian Rhythm, Microbiome, Occupational Health, PNAS / 15.07.2018

MedicalResearch.com Interview with: Dr. Hans Van Dongen, PhD Director of the Sleep and Performance Research Center. ELSON S. FLOYD COLLEGE OF MEDICIN Washington State University Spokane, WA MedicalResearch.com: What is the background for this study? Response: Night shift workers are at increased risk of metabolic disorders, including obesity and type 2 diabetes, as well as cardiovascular disease, chronic kidney disease, and cancer. Although it is believed that the biological clock – the master circadian clock in the brain – plays an important role in these adverse chronic health consequences of night shift work, the underlying mechanisms are not well understood. (more…)
Author Interviews, Circadian Rhythm, Lancet, Mental Health Research / 16.05.2018

MedicalResearch.com Interview with: Laura Lyall MA; MSc; PhD Research Associate Institute of Health and Wellbeing University of Glasgow MedicalResearch.com: What is the background for this study? Response: Previous studies have suggested a link between disturbed circadian rhythms and depression and bipolar disorder. These studies have however usually used small samples, subjective measures of circadian disruption, or have not accounted for potential confounding factors like sociodemographic and lifestyle characteristics. The UK Biobank cohort has accelerometry (activity monitor) data as well as mental health, lifestyle, BMI and sociodemographic data for over 91,000 individuals, and means we can address this question using objective measures of circadian rhythmicity on a large scale. We derived a measure of relative amplitude from the UK Biobank’s accelerometry data, which was recorded for 7 days between 2013-2014 from around 100,000 participants. Relative amplitude reflects the distinction, in terms of activity levels, between an individual’s most active 10 hours and least active 5 hours, in an average day. If an individual is inactive during the day, or has disturbed sleep at night, the will show low relative amplitude, consistent with disturbed circadian rest-activity patterns. (more…)
Aging, Author Interviews, Circadian Rhythm, Sleep Disorders / 29.03.2018

MedicalResearch.com Interview with: “Woman sleeping” by Timothy Krause is licensed under CC BY 2.0Dr Gurprit S. Lall BSc, MSc, PhD, PGCHE, FHEA Medway School of Pharmacy Interim Deputy Head of School Senior Lecturer in Pharmacology Director of Graduate Studies (Research), University of Kent at Medway Chatham Maritime, Chatham, Kent MedicalResearch.com: What is the background for this study? What are the main findings? Response: Medical advancement in prevention and diagnosis of disease has increased life expectancy significantly, thus generating an ageing population far greater than previously seen.  Because of this, it is essential that we begin to understand the ageing process, together with the health implications associated with senescence.  Recent research has found that changes in the circadian clock, located in the brain, play a contributing role in the decline of many physiological and behavioural traits observed through the ageing process.  One example of this, which is commonly seen in the elderly is a decline in sleep-wake cycle regulation; typically presenting as disrupted sleeping patterns. The circadian clock, in mammals, possesses the ability to integrate our social lifestyle choices with the environmental day-night cycle to generate a 24-hour rhythm to which our physiological functions are synchronised.  It is this synchronisation that plays a vital role in regulating many of our behavioural outputs, such as sleeping-wake patterns.  This clock takes its strongest timing cue from the natural day night cycle governed by the duration of daily sunlight. Our study investigated the changes in the interpretation of this light signal by the circadian clock as we age and its impact on function.  We found that the clock became less responsive to light stimuli at both the level of clock cells and at driving behavioural activity.  We were able to narrow this down to changes in the proteins within cells that relay light information to the molecular time setting machinery.  In detail, light signals are relayed to the clock through an excitatory neurotransmitter called glutamate and this signal is predominantly relayed through NMDA receptors located on the surface of clock cells.  It is the configuration of the NMDA receptor that alters as we age and this leads to the clock becoming less responsive to light. (more…)
Alzheimer's - Dementia, Author Interviews, Circadian Rhythm, JAMA / 30.01.2018

MedicalResearch.com Interview with: “mirror clock” by tourist_on_earth is licensed under CC BY 2.0Yo-El Ju, MD Assistant Professor of Neurology Sleep Medicine Section Washington University School of Medicine MedicalResearch.com: What is the background for this study? What are the main findings? Response: The background for this study is that prior studies have shown that people with Alzheimer's Disease have poor circadian clock function, for example sleeping during the day and being awake or agitated at night. Autopsy studies have shown that people with Alzheimer's Disease have degeneration in the "clock" part of their brains. In this study, we wanted to examine whether there were any circadian problems much earlier in Alzheimer's Disease, when people do not have any memory or thinking problems at all. We measured circadian function in 189 people with an actigraph, which is an activity monitor worn like a watch, for 1-2 weeks. Brain scans and studies of cerebrospinal fluid were used to determine who had preclinical Alzheimer's Disease, meaning they have the brain changes of Alzheimer's but do not have symptoms yet.  (more…)
Abuse and Neglect, Circadian Rhythm, Heart Disease, Lancet, Surgical Research / 03.11.2017

MedicalResearch.com Interview with: Prof David Montaigne MD Faculté de Médecine de Lille H Warembourg Lille, France MedicalResearch.com: What is the background for this study? What are the main findings? Response: It is well known for many decades that cardiovascular diseases exhibit a diurnal variation with for instance higher incidence of myocardial infarction in the early morning as opposed to the evening. Although studies on circadian gene knock-out and mutant mice argue for a biorhythm in myocardial ischemia-reperfusion tolerance, whether a biorhythm in the myocardial tolerance to ischemia, exists in humans was unclear because of conflicting reports in the context of myocardial infarction. We demonstrated for the first time in humans that the myocardial tolerance to ischemia-reperfusion is different along the day, in line with rodent experiments performed in the early 2010s. We demonstrated that this biorhythm is clinically meaningful and that it can be targeted as a cardioprotective strategy. In this topic, Rever-alpha is of specific interest. It belongs at the same time to circadian genes and nuclear receptor families: being a nuclear receptor, it is a feasible pharmacological target, conversely to other circadian genes. (more…)
Author Interviews, Circadian Rhythm, Neurological Disorders, Neurology / 21.04.2017

MedicalResearch.com Interview with: Dr. Christine Blume PhD Post-Doctoral Researcher University of Salzburg Centre for Cognitive Neuroscience (CCNS) Laboratory for Sleep, Cognition & Consciousness Research Salzburg MedicalResearch.com: What is the background for this study? What are the main findings? Response: We are governed by rhythmic processes. Many of these processes follow a circadian pattern, that is, they have a period length of approximately 24 hours and are under tight control of a biological master clock located in the suprachiasmatic nucleus of the hypothalamus. Given the circadian variation in global states like alertness, it is not surprising that consciousness also varies rhythmically in healthy individuals, it follows the sleep-wake cycle. From a clinical perspective, misalignment of circadian rhythms, which occurs when the sleep-wake schedule is at odds with the light-dark cycle as in the case of night shifts, can cause considerable stress, have detrimental effects on the immune system and impair cognitive abilities. Despite the knowledge that entrained circadian rhythms are important for healthy body and brain functioning, very little is known about circadian rhythms in patients diagnosed with a disorder of consciousness (DOC) following severe brain injuries. We argue that studying circadian rhythms in DOC patients may be especially interesting and important for two reasons. First, the presence or absence of circadian rhythms as well as anomalies in them could be informative about the state of the patient as well as their potential for recovery. Second, this could provide information about time points that best capture remaining cognitive functions thereby minimising the risk of misdiagnoses. Beyond this, examining circadian processes may also provide targets for therapeutic interventions such as light stimulation, which has proven successful in individuals with e.g. circadian sleep disorders. Interestingly, analyses with Lomb-Scargle periodograms revealed significant circadian rhythmicity in all patients (range 23.5-26.3h). We found that especially scores on the arousal subscale of the Coma Recovery Scale-Revised (CRS-R) were closely linked to the integrity of circadian variations in body temperature. Finally, we piloted whether bright light stimulation could boost circadian rhythmicity and found positive evidence in two out of eight patients. (more…)
Author Interviews, Circadian Rhythm, Nutrition, Sleep Disorders, Weight Research / 01.03.2017

MedicalResearch.com Interview with: Mirkka Maukonen MSc (nutrition), PhD Candidate the National Institute for Health and Welfare, Department of Public Health Solutions Helsinki, Finland MedicalResearch.com: What is the background for this study? Response: Recent literature has highlighted the importance of sleep and circadian rhythms in development of obesity and metabolic dysfunctions. Furthermore, it has been suggested that in addition to quality of the diet also meal timing may play role in development of obesity. For example, skipping breakfast and eating at later times in the evening have been associated with higher BMI. However, little is known about how the timing of circadian rhythms (chronotype) affects timing of energy intake and its association with metabolic health. (more…)
Author Interviews, Circadian Rhythm, Toxin Research / 20.01.2017

MedicalResearch.com Interview with: Rajendram Rajnarayanan PhD Department of Pharmacology and Toxicology Assistant Professor Jacobs School of Medicine and Biomedical Sciences University of Buffalo MedicalResearch.com: What is the background for this study? What are the main findings? Response: Human exposure to environmental chemicals i.e., insecticides and pesticides increases the risk of various diseases by directly interacting with proteins or signaling pathways in the endocrine or neuroendocrine system. In this study, our teamscience effort integrating big-data computation with receptor pharmacology, report for the first time that carbamate insecticides found in household and agricultural products interact with human melatonin receptors. At UB we have generated a database, we call it Chem2Risk, which contains about four million chemicals reported to have some level of toxicity. From those, after grouping the chemicals in clusters according to their similarity, we found several with potential to mimic melatonin. Wet-lab experiments confirmed that these chemicals indeed interact with melatonin receptors and have the potential to alter melatonin signaling. (more…)
Author Interviews, Circadian Rhythm, Sleep Disorders / 22.12.2016

MedicalResearch.com Interview with: Dr. Nicola Barclay, BA(Hons), MSc, PhD. Lecturer in Sleep Medicine Sleep and Circadian Neuroscience Institute (SCNi) Nuffield Department of Clinical Neurosciences Sir William Dunn School of Pathology University of Oxford MedicalResearch.com: What is the background for this study? Response: We know that extreme sleep deprivation impairs our cognitive functions, particularly attention. This impairment in attention is likely to be driven by physiological mechanisms that change across the waking day (increasing sleep pressure), but also by factors associated with our biological clock. The timing of physiological processes particularly related to attention differ between morning and evening type people (our so called early morning larks and night owls), and so we hypothesised that morning and evening types would differ in their impairments in attention at different times of day, prior to and following 18 hours of sustained wakefulness. (more…)
Author Interviews, Circadian Rhythm, Sleep Disorders, Weight Research / 15.06.2016

MedicalResearch.com Interview with: Kelly Glazer Baron, PhD, MPH, C. B.S.M. Diplomate, Academy of Cognitive Therapy Northwestern University Feinberg School of Medicine Chicago, IL 60611 MedicalResearch.com: What is the background for this study? What are the main findings? Response: In contrast to several previous studies, being a late sleeper was not associated with higher BMI (good news for late sleepers!!) but it was associated with less healthy behaviors, more fast food, fewer vegetables, lower dairy. It may be possible that these late sleepers who are able to get enough sleep can compensate for their poor diet by controlling overall calories or it could possibly lead to weight gain over time if their habits continue over time. (more…)
Author Interviews, Circadian Rhythm, Endocrinology, Lifestyle & Health, Occupational Health, Sleep Disorders, Stroke / 02.06.2016

MedicalResearch.com Interview with: David Earnest, Ph.D. Professor in the Department of Neuroscience and Experimental Therapeutics Texas A&M Health Science Center College of Medicine MedicalResearch.com: What is the background for this study? What are the main findings? Dr. Earnest: When body clocks are disrupted, as they are when people engage in shift work or go to bed and get up at radically different times every few days, more severe ischemic strokes can result. MedicalResearch.com: What should readers take away from your report? Dr. Earnest:  Whenever possible, go to bed and get up at the same time each day and keep regular mealtimes. If you do need to keep an irregular schedule, it is especially important to be mindful of stroke risk and try especially hard to eliminate other risk factors, such as hypertension and obesity. (more…)
Author Interviews, Circadian Rhythm, Ophthalmology, Sleep Disorders, UCSD / 09.04.2015

MedicalResearch.com Interview with: Carolina P B Gracitelli, M.D. Ophthalmology - PhD Candidate/ Research Fellow University of California San Diego - Hamilton Glaucoma Center Medical Research: What is the background for this study? What are the main findings? Dr. Gracitelli: Of all the diseases that can lead to blindness, glaucoma is one of the most important diseases; it affects more than 70 million people worldwide, of whom approximately 10 % are bilaterally blind. Different studies have reported that the damage caused by glaucomatous disease lead to retinal ganglion cell (RGC) loss and consequently loss of intrinsically photosensitive retinal ganglion cells (ipRGCs), which is a subtype of RGC. This subpopulation of RGC is clearly related with non-image-forming visual function such as photic synchronization of circadian rhythms and the pupillary light reflex. However, the true impact of glaucoma on sleep quality, sleep disturbance or circadian rhythm was until nowadays controversial. The main clinical finding of our study was that glaucoma leads to RGC death, including ipRGC death. These cells are connected to several non-image-forming functions, including circadian photoentrainment and pupillary reflexes. Therefore, the image-forming and non-image-forming visual systems are associated with glaucoma. Circadian function has not been well investigated in clinical daily practice, but it can interfere with the quality of life of these patients. Concerns about sleep disturbances in glaucoma patients should be incorporated into clinical evaluations. Medical Research: What should clinicians and patients take away from your report? Dr. Gracitelli: Our data support the concept that glaucoma is associated with a loss of ipRGCs that mediate the pupillary light response, particularly to the sustained component of the blue flash with a luminance of 250 cd/m2. Additionally, glaucoma patients had significant sleep disturbances that were inversely correlated with a measure of ipRGC function, the pupillary light reflex. These results suggest that the loss of ipRGCs in glaucoma may also lead to sleep disturbances. Both non-visual functions of ipRGCs are correlated, indicating that attention should be paid to the non-image forming visual functions in glaucoma patients. Medical Research: What recommendations do you have for future research as a result of this study? Dr. Gracitelli: Sleep disorders is a complex system, therefore, some conclusions in this study should be carefully evaluated. Further studies with larger cohorts could also help to elucidate the association between the pupillary reflex and the polysomnography parameters. And longitudinal studies can better explain the associations between sleep disorders and glaucoma progression. In addition, we know that there are several types of ipRGCs and they have specific functions (pupillary reflex or circadian rhythms), therefore, evaluations would also need to include a more thorough assessment to understand better the specific role of ipRGCs in sleep disturbances. However, it is true that these ipRGCs functions are impaired in glaucoma, affecting the quality of life of these patients. Citation: Intrinsically Photosensitive Retinal Ganglion Cell Activity Is Associated with Decreased Sleep Quality in Patients with Glaucoma Gracitelli, Carolina P.B. et al. Ophthalmology Published Online: April 06, 2015 DOI: http://dx.doi.org/10.1016/j.ophtha.2015.02.030MedicalResearch.com Interview with: Carolina P B Gracitelli, M.D. Ophthalmology - PhD Candidate/ Research Fellow University of California San Diego - Hamilton Glaucoma Center Medical Research: What is the background for this study? What are the main findings? Dr. Gracitelli: Of all the diseases that can lead to blindness, glaucoma is one of the most important diseases; it affects more than 70 million people worldwide, of whom approximately 10 % are bilaterally blind. Different studies have reported that the damage caused by glaucomatous disease lead to retinal ganglion cell (RGC) loss and consequently loss of intrinsically photosensitive retinal ganglion cells (ipRGCs), which is a subtype of retinal ganglion cell. This subpopulation of RGC is clearly related with non-image-forming visual function such as photic synchronization of circadian rhythms and the pupillary light reflex. However, the true impact of glaucoma on sleep quality, sleep disturbance or circadian rhythm was until nowadays controversial. The main clinical finding of our study was that glaucoma leads to retinal ganglion cell death, including ipRGC death. These cells are connected to several non-image-forming functions, including circadian photoentrainment and pupillary reflexes. Therefore, the image-forming and non-image-forming visual systems are associated with glaucoma. Circadian function has not been well investigated in clinical daily practice, but it can interfere with the quality of life of these patients. Concerns about sleep disturbances in glaucoma patients should be incorporated into clinical evaluations. (more…)
Author Interviews, Circadian Rhythm, CMAJ / 27.01.2015

Scott R. Garrison MD PhD Associate Professor, Department of Family Medicine Director, Pragmatic Trials Collaborative Faculty of Medicine University of Alberta EdmontonMedicalResearch.com Interview with: Scott R. Garrison MD PhD Associate Professor, Department of Family Medicine Director, Pragmatic Trials Collaborative Faculty of Medicine University of Alberta Edmonton MedicalResearch: What is the background for this study? What are the main findings? Dr. Garrison: Nocturnal leg cramps (also called rest cramps) are painful muscle tightenings, most often in the legs or feet, that are brought on by rest and often wake the sufferer from sleep. They are very common in older adults and can also occur during pregnancy. Having read anecdotal mention that the rest cramps of pregnancy appeared to be worse in summer we sought cohort level evidence to determine whether the more common presentation of age-related rest cramps was also seasonal. To do this we primarily looked at new quinine starts in the province of British Columbia over a period of several years. British Columbia has a publicly funded health care system and maintains electronic records on all health services, including prescription drugs, provided to its roughly 4.2 million residents. Quinine is approved for the treatment of acute malaria in Canada but is instead almost exclusively used off-label to prevent rest cramps. As such, new quinine starts are an excellent marker for new or escalating cramp burden. We also looked at Internet searches, geographically limited to the USA, for the term “leg cramps” (reflecting public interest) obtained from the Google Trends Search Volume Index Tool. Seasonality for both of these indicators of cramp burden was assessed by determining how well a least squares minimizing sinusoidal model predicted variability. We found that quinine starts and "leg cramp" related Internet queries were both strikingly sinusoidal with a 365-day periodicity (mid-summer high, mid-winter low) and a peak-to-peak variability that is approximately 2/3 of the mean. Seasonality accounted for 88% of the observed monthly variability (p < 0.0001) in quinine starts, and 70% of the observed variability (p < 0.0001) in “leg cramp” related internet searches. (more…)
Alcohol, Author Interviews, Circadian Rhythm / 20.01.2015

Timo Partonen MD, Research Professor National Institute for Health and Welfare Helsinki, FinlandMedicalResearch.com Interview with: Timo Partonen MD, Research Professor National Institute for Health and Welfare Helsinki, Finland Medical Research: What is the background for this study? What are the main findings? Response: Alcohol-use disorders are often comorbid conditions with mood and anxiety disorders. Clinical studies have demonstrated that there are abnormalities in circadian rhythms and intrinsic clocks in patients with alcohol-use disorders. Circadian clock gene variants are therefore a fruitful target of interest. The main findings are that variants of key clock genes, namely those of ARNTL, ARNTL2, PER1 and PER2, have association with alcohol consumption, with alcohol abuse, or with alcohol dependence. It is of interest that variants of a fifth clock gene of key importance, that is those of CLOCK, are associated with alcohol-use disorders only if comorbid with depressive disorders. (more…)