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Bilu C, Butensky N, Malamud AR, Einat H, Zimmet P, Zloto O, Ziv H, Kronfeld-Schor N, Vishnevskia-Dai V. Effects of photoperiod and food on glucose intolerance and subsequent ocular pathology in the fat sand rat. Sci Rep 2024; 14:403. [PMID: 38172147 PMCID: PMC10764329 DOI: 10.1038/s41598-023-44584-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Accepted: 10/10/2023] [Indexed: 01/05/2024] Open
Abstract
Type 2 diabetes mellitus (T2DM) and its ocular complications, such as cataract and diabetic retinopathy (DR) have been linked to circadian rhythm-disturbances. Using a unique diurnal animal model, the sand rat (Psammomys obesus) we examined the effect of circadian disruption by short photoperiod acclimation on the development of T2DM and related ocular pathologies. We experimented with 48 male sand rats. Variables were day length (short photoperiod, SP, vs. neutral photoperiod NP) and diet (standard rodent diet vs. low-energy diet). Blood glucose, the presence of cataract and retinal pathology were monitored. Histological slides were examined for lens opacity, retinal cell count and thickness. Animals under SP and fed standard rodent diet (SPSR) for 20 weeks had higher baseline blood glucose levels and lower glucose tolerance compared with animals kept under NP regardless of diet, and under SP with low energy diet (SPLE). Animals under SPSR had less cells in the outer nuclear layer, a lower total number of cells in the retina, and a thickened retina. Higher blood glucose levels correlated with lower number of cells in all cellular layers of the retina and thicker retina. Animals under SPSR had higher occurrence of cataract, and a higher degree of cataract, which correlated with higher blood glucose levels. Sand rats kept under SPSR develop cataract and retinal abnormalities indicative of DR, whereas sand rats kept under NP regardless of diet, or under SPLE, do not. These ocular abnormalities significantly correlate with hyperglycemia.
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Affiliation(s)
- Carmel Bilu
- School of Zoology, Tel-Aviv University, 69978, Ramat Aviv, Tel Aviv, Israel.
| | - Neta Butensky
- School of Zoology, Tel-Aviv University, 69978, Ramat Aviv, Tel Aviv, Israel
| | | | - Haim Einat
- School of Behavioral Sciences, Tel Aviv-Yaffo Academic College, Tel-Aviv, Israel
| | - Paul Zimmet
- Department of Medicine, Monash University, Melbourne, VIC, Australia
| | - Ofira Zloto
- Ocular Oncology, The Goldschleger Eye Institute, The Chaim Sheba Medical Center, Tel-Hashomer, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Hana Ziv
- Maurice and Gabriela Goldschleger Eye Research Institute, The Chaim Sheba Medical Center, Tel-Hashomer, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | | | - Vicktoria Vishnevskia-Dai
- Ocular Oncology, The Goldschleger Eye Institute, The Chaim Sheba Medical Center, Tel-Hashomer, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel
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Bilu C, Einat H, Zimmet P, Kronfeld-Schor N. Circadian rhythms-related disorders in diurnal fat sand rats under modern lifestyle conditions: A review. Front Physiol 2022; 13:963449. [PMID: 36160856 PMCID: PMC9489903 DOI: 10.3389/fphys.2022.963449] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 08/11/2022] [Indexed: 11/17/2022] Open
Abstract
Modern lifestyle reduces environmental rhythmicity and may lead to circadian desynchrony. We are exposed to poor day-time lighting indoors and excessive night-time artificial light. We use air-conditioning to reduce ambient temperature cycle, and food is regularly available at all times. These disruptions of daily rhythms may lead to type 2 diabetes mellitus (T2DM), obesity, cardiometabolic diseases (CMD), depression and anxiety, all of which impose major public health and economic burden on societies. Therefore, we need appropriate animal models to gain a better understanding of their etiologic mechanisms, prevention, and management.We argue that the fat sand rat (Psammomys obesus), a diurnal animal model, is most suitable for studying the effects of modern-life conditions. Numerous attributes make it an excellent model to study human health disorders including T2DM, CMD, depression and anxiety. Here we review a comprehensive series of studies we and others conducted, utilizing the fat sand rat to study the underlying interactions between biological rhythms and health. Understanding these interactions will help deciphering the biological basis of these diseases, which often occur concurrently. We found that when kept in the laboratory (compared with natural and semi-wild outdoors conditions where they are diurnal), fat sand rats show low amplitude, nocturnal or arrhythmic activity patterns, dampened daily glucose rhythm, glucose intolerance, obesity and decreased survival rates. Short photoperiod acclimation exacerbates these pathologies and further dampens behavioral and molecular daily rhythms, resulting in CMD, T2DM, obesity, adipocyte dysfunction, cataracts, depression and anxiety. Increasing environmental rhythmicity by morning bright light exposure or by access to running wheels strengthens daily rhythms, and results in higher peak-to-trough difference in activity, better rhythmicity in clock genes expression, lower blood glucose and insulin levels, improved glucose tolerance, lower body and heart weight, and lower anxiety and depression. In summary, we have demonstrated that fat sand rats living under the correspondent of “human modern lifestyle” conditions exhibit dampened behavioral and biological rhythms and develop circadian desynchrony, which leads to what we have named “The Circadian Syndrome”. Environmental manipulations that increase rhythmicity result in improvement or prevention of these pathologies. Similar interventions in human subjects could have the same positive results and further research on this should be undertaken.
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Affiliation(s)
- Carmel Bilu
- School of Zoology, Tel-Aviv University, Tel Aviv, Israel
- *Correspondence: Carmel Bilu,
| | - Haim Einat
- School of Behavioral Sciences, Tel Aviv-Yaffo Academic College, Tel-Aviv, Israel
| | - Paul Zimmet
- Department of Diabetes, Monash University, Melbourne, VIC, Australia
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Bilu C, Kronfeld-Schor N, Zimmet P, Einat H. Day and night: A comment on "Neurobiological and behavioral mechanisms of circadian rhythm disruption in bipolar disorder: A critical multi-disciplinary literature review and agenda for future research from the ISBD task force on chronobiology". Bipolar Disord 2022; 24:211-212. [PMID: 35167169 DOI: 10.1111/bdi.13189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Carmel Bilu
- School of Zoology, Tel-Aviv University, Tel-Aviv, Israel
| | | | - Paul Zimmet
- Department of Diabetes, Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - Haim Einat
- Tel Aviv-Yaffo Academic College, Tel Aviv, Israel
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Bilu C, Einat H, Zimmet P, Vishnevskia-Dai V, Schwartz WJ, Kronfeld-Schor N. Beneficial effects of voluntary wheel running on activity rhythms, metabolic state, and affect in a diurnal model of circadian disruption. Sci Rep 2022; 12:2434. [PMID: 35165331 PMCID: PMC8844006 DOI: 10.1038/s41598-022-06408-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 01/19/2022] [Indexed: 12/14/2022] Open
Abstract
Emerging evidence suggests that disruption of circadian rhythmicity contributes to development of comorbid depression, cardiovascular diseases (CVD), and type 2 diabetes mellitus (T2DM). Physical exercise synchronizes the circadian system and has ameliorating effects on the depression- and anxiety-like phenotype induced by circadian disruption in mice and sand rats. We explored the beneficial effects of voluntary wheel running on daily rhythms, and the development of depression, T2DM, and CVD in a diurnal animal model, the fat sand rat (Psammomys obesus). Voluntary exercise strengthened general activity rhythms, improved memory and lowered anxiety- and depressive-like behaviors, enhanced oral glucose tolerance, and decreased plasma insulin levels and liver weight. Animals with access to a running wheel had larger heart weight and heart/body weight ratio, and thicker left ventricular wall. Our results demonstrate that exercising ameliorates pathological-like daily rhythms in activity and blood glucose levels, glucose tolerance and depressive- and anxiety-like behaviors in the sand rat model, supporting the important role of physical activity in modulating the “circadian syndrome” and circadian rhythm-related diseases. We suggest that the utilization of a diurnal rodent animal model may offer an effective way to further explore metabolic, cardiovascular, and affective-like behavioral changes related to chronodisruption and their underlying mechanisms.
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Abstract
Most animal model studies on physiological functions and pathologies are conducted in males. However, diseases such as depression, type 2 diabetes (T2DM) and cardiovascular disease, all show different prevalence and characteristics in females and males. Moreover, most mammal studies are conducted in nocturnal mice and rats, while modelling diurnal humans. We therefore used male and female fat sand rats (Psammomys obesus), which are diurnal in the wild, as an animal model for T2DM, to explore the effects of mild circadian disruption on behavior, glucose tolerance, cholesterol and heart weight. We found significant differences between the sexes: on average, in response to short photoperiods (SP) acclimation, males showed higher levels of depression-like behavior, lower glucose tolerance, and increased plasma cholesterol levels compared with females, with no effect on heart/body weight ratio. Females, however did show an increase in heart/body weight ratio in response to SP acclimation. We also found that regardless of sex, arrhythmic animals showed higher blood glucose levels, cholesterol levels, heart/body weight ratio, and depressive-like behavior compared with rhythmic animals. Hence, we suggest that the expression of the Circadian Syndrome could be different between males and females. Additional work with females is required to clearly delineate the specific effects in both sexes, and promote sex-based health care, prevention measures and therapies.
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Affiliation(s)
- Carmel Bilu
- School of Zoology, Tel-Aviv University, Tel Aviv, Israel
| | - Noga Kronfeld-Schor
- School of Zoology, Tel-Aviv University, Tel Aviv, Israel.,Sagol School of Neuroscience, Tel-Aviv University, Tel Aviv, Israel
| | - Paul Zimmet
- Department of Medicine, Monash University, Melbourne, Australia
| | - Haim Einat
- School of Behavioral Sciences, Tel Aviv-Yaffo Academic College, Tel-Aviv, Israel
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Shi Z, Tuomilehto J, Kronfeld-Schor N, Alberti GK, Stern N, El-Osta A, Bilu C, Einat H, Zimmet P. The circadian syndrome predicts cardiovascular disease better than metabolic syndrome in Chinese adults. J Intern Med 2021; 289:851-860. [PMID: 33340184 DOI: 10.1111/joim.13204] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/11/2020] [Accepted: 10/19/2020] [Indexed: 12/11/2022]
Abstract
BACKGROUND To compare the predictive value of the circadian syndrome (CircS) and Metabolic syndrome (MetS) for cardiovascular disease. METHOD We used the data of 9360 Chinese adults aged ≥40 years from the 2011 China Health and Retirement Longitudinal Study (CHARLS). Of the participants, 8253 people were followed in the 2015 survey. MetS was defined using the harmonized criteria. CircS was based on the components of the International Diabetes Federation (IDF) MetS plus short sleep and depression. The cut-off for CircS was set as ≥4. Multivariable logistic regression analysis was used to examine the associations. RESULTS The prevalence of CircS and MetS was 39.0% and 44.7%. Both MetS and CircS were directly associated with prevalent CVD. The odds ratios for prevalent CVD comparing CircS with MetS, respectively, were 2.83 (95%CI 2.33-3.43) and 2.34 (1.93-2.83) in men, and 2.33 (1.98-2.73) and 1.79 (1.53-2.10) in women. Similar associations were found for incident CVD. The five-year incidence of CVD was 15.1% in CircS and 14.0% in MetS. The number of CircS components has a better predictive power for both prevalent and incident CVD than those of Mets components as indicated by the area under the ROC (AUC). AUC values for CVD in 2011 were higher for CircS than MetS in both men (0.659 (95%CI 0.634-0.684) vs 0.635 (95%CI 0.610-0.661)) and women (0.652 (95%CI 0.632-0.672) vs 0.619 (95%CI 0.599-0.640)). CONCLUSION The circadian syndrome is a strong and better predictor for CVD than the metabolic syndrome in Chinese adults.
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Affiliation(s)
- Z Shi
- From the, Human Nutrition Department, College of Health Sciences, QU Health, Qatar University, Doha, Qatar
| | - J Tuomilehto
- Department of Public Health, University of Helsinki, Helsinki, Finland
| | | | - G K Alberti
- Department of Endocrinology and Metabolism Imperial, College London, London, UK
| | - N Stern
- Sagol Epigenetics Center, Tel Aviv Medical Center, Tel Aviv, Israel
| | - A El-Osta
- Department of Diabetes, Central Clinical School, Monash University, Melbourne, Vic., Australia.,The Chinese University of Hong Kong, Hong Kong SAR, China
| | - C Bilu
- School of Zoology, Tel Aviv University, Tel Aviv, Israel
| | - H Einat
- School of Behavioral Sciences, Tel Aviv-Yaffo Academic College, Tel Aviv, Israel
| | - P Zimmet
- Sagol Epigenetics Center, Tel Aviv Medical Center, Tel Aviv, Israel.,Department of Diabetes, Central Clinical School, Monash University, Melbourne, Vic., Australia
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Nankivell VA, Tan JTM, Wilsdon LA, Morrison KR, Bilu C, Psaltis PJ, Zimmet P, Kronfeld-Schor N, Nicholls SJ, Bursill CA, Brown A. Circadian disruption by short light exposure and a high energy diet impairs glucose tolerance and increases cardiac fibrosis in Psammomys obesus. Sci Rep 2021; 11:9673. [PMID: 33958671 PMCID: PMC8102519 DOI: 10.1038/s41598-021-89191-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 04/20/2021] [Indexed: 12/22/2022] Open
Abstract
Type 2 diabetes mellitus (T2DM) increases cardiac inflammation which promotes the development of cardiac fibrosis. We sought to determine the impact of circadian disruption on the induction of hyperglycaemia, inflammation and cardiac fibrosis. METHODS Psammomys obesus (P. obesus) were exposed to neutral (12 h light:12 h dark) or short (5 h light:19 h dark) photoperiods and fed a low energy (LE) or high energy (HE) diet for 8 or 20 weeks. To determine daily rhythmicity, P. obesus were euthanised at 2, 8, 14, and 20 h after 'lights on'. RESULTS P. obesus exposed to a short photoperiod for 8 and 20 weeks had impaired glucose tolerance following oral glucose tolerance testing, compared to a neutral photoperiod exposure. This occurred with both LE and HE diets but was more pronounced with the HE diet. Short photoperiod exposure also increased myocardial perivascular fibrosis after 20 weeks on LE (51%, P < 0.05) and HE (44%, P < 0.05) diets, when compared to groups with neutral photoperiod exposure. Short photoperiod exposure caused elevations in mRNA levels of hypertrophy gene Nppa (atrial natriuretic peptide) and hypertrophy transcription factors Gata4 and Mef2c in myocardial tissue after 8 weeks. CONCLUSION Exposure to a short photoperiod causes impaired glucose tolerance in P. obesus that is exacerbated with HE diet and is accompanied by an induction in myocardial perivascular fibrosis.
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Affiliation(s)
- Victoria A Nankivell
- South Australian Health & Medical Research Institute, Adelaide, Australia.,Faculty of Health and Medical Science, The University of Adelaide, Adelaide, Australia.,ARC Centre of Excellence for Nanoscale BioPhotonics, The University of Adelaide, Adelaide, Australia
| | - Joanne T M Tan
- South Australian Health & Medical Research Institute, Adelaide, Australia.,Faculty of Health and Medical Science, The University of Adelaide, Adelaide, Australia
| | - Laura A Wilsdon
- South Australian Health & Medical Research Institute, Adelaide, Australia
| | - Kaitlin R Morrison
- South Australian Health & Medical Research Institute, Adelaide, Australia
| | - Carmel Bilu
- School of Zoology, Tel Aviv University, Tel Aviv, Israel
| | - Peter J Psaltis
- South Australian Health & Medical Research Institute, Adelaide, Australia.,Faculty of Health and Medical Science, The University of Adelaide, Adelaide, Australia
| | - Paul Zimmet
- Department of Diabetes, Monash University, Melbourne, Australia
| | | | - Stephen J Nicholls
- Monash Cardiovascular Research Centre, Victorian Heart Institute, Monash University, Melbourne, Australia
| | - Christina A Bursill
- South Australian Health & Medical Research Institute, Adelaide, Australia. .,Faculty of Health and Medical Science, The University of Adelaide, Adelaide, Australia. .,ARC Centre of Excellence for Nanoscale BioPhotonics, The University of Adelaide, Adelaide, Australia. .,Vascular Research Centre, Lifelong Health Theme, South Australian Health & Medical Research Institute, North Terrace, Adelaide, SA, 5000, Australia.
| | - Alex Brown
- South Australian Health & Medical Research Institute, Adelaide, Australia.,Faculty of Health and Medical Science, The University of Adelaide, Adelaide, Australia
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Tan JT, Nankivell VA, Bilu C, Shemesh T, Nicholls SJ, Zimmet P, Kronfeld-Schor N, Brown A, Bursill CA. High-Energy Diet and Shorter Light Exposure Drives Markers of Adipocyte Dysfunction in Visceral and Subcutaneous Adipose Depots of Psammomys obesus. Int J Mol Sci 2019; 20:ijms20246291. [PMID: 31847097 PMCID: PMC6940992 DOI: 10.3390/ijms20246291] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 12/09/2019] [Accepted: 12/11/2019] [Indexed: 02/07/2023] Open
Abstract
Dysfunctional adipose tissue phenotype underpins type 2 diabetes mellitus (T2DM) development. The disruption of circadian rhythms contributes to T2DM development. We investigated the effects of high-energy diet and photoperiod length on visceral and subcutaneous adipose tissue phenotype. Psammomys obesus sand rats exposed to neutral (12 light:12 dark) or short (5 light:19 dark) photoperiod were fed a low- (LE) or high- (HE) energy diet. The HE diet and/or short photoperiod reduced subcutaneous expression of adipocyte differentiation/function markers C/ebpα, Pparδ, Pparγ and Adipoq. Visceral Pparα levels were elevated in the 5:19HE group; however, the HE diet and/or short photoperiod decreased visceral Pparγ and Adipoq expression. 5:19HE animals had elevated Ucp1 yet lower Pgc-1α levels. The HE diet increased visceral Tgf-β1, Ccl2 and Cd68 levels, suggestive of a pro-inflammatory state. Daily visceral rhythms of these genes were affected by a short photoperiod and/or HE diet. The 12:12HE, 5:19LE or 5:19HE animals had a higher proportion of larger adipocytes, indicating increased adipocyte hypertrophy. Collectively, the HE diet and/or shorter light exposure drives a dysfunctional adipose tissue phenotype. Daily rhythms are affected by a short photoperiod and HE diet in a site-specific manner. These findings provide mechanistic insight on the influence of disrupted circadian rhythms and HE diet on adipose tissue phenotype.
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Affiliation(s)
- Joanne T.M. Tan
- South Australian Health & Medical Research Institute, Adelaide SA 5000, Australia; (V.A.N.); (T.S.); (P.Z.); (A.B.); (C.A.B.)
- Adelaide Medical School, The University of Adelaide, Adelaide SA 5005, Australia
- Correspondence: ; Tel.: +61-8-8128-4789
| | - Victoria A. Nankivell
- South Australian Health & Medical Research Institute, Adelaide SA 5000, Australia; (V.A.N.); (T.S.); (P.Z.); (A.B.); (C.A.B.)
- Adelaide Medical School, The University of Adelaide, Adelaide SA 5005, Australia
| | - Carmel Bilu
- School of Zoology, Tel Aviv University, Tel Aviv, Ramat Aviv 69978, Israel; (C.B.); (N.K.-S.)
| | - Tomer Shemesh
- South Australian Health & Medical Research Institute, Adelaide SA 5000, Australia; (V.A.N.); (T.S.); (P.Z.); (A.B.); (C.A.B.)
| | - Stephen J. Nicholls
- Monash Cardiovascular Research Centre, Monash University, Clayton VIC 3168, Australia;
| | - Paul Zimmet
- South Australian Health & Medical Research Institute, Adelaide SA 5000, Australia; (V.A.N.); (T.S.); (P.Z.); (A.B.); (C.A.B.)
- Department of Diabetes, Monash University, Clayton VIC 3800, Australia
| | - Noga Kronfeld-Schor
- School of Zoology, Tel Aviv University, Tel Aviv, Ramat Aviv 69978, Israel; (C.B.); (N.K.-S.)
| | - Alex Brown
- South Australian Health & Medical Research Institute, Adelaide SA 5000, Australia; (V.A.N.); (T.S.); (P.Z.); (A.B.); (C.A.B.)
- Adelaide Medical School, The University of Adelaide, Adelaide SA 5005, Australia
| | - Christina A. Bursill
- South Australian Health & Medical Research Institute, Adelaide SA 5000, Australia; (V.A.N.); (T.S.); (P.Z.); (A.B.); (C.A.B.)
- Adelaide Medical School, The University of Adelaide, Adelaide SA 5005, Australia
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Bilu C, Einat H, Barak O, Zimmet P, Vishnevskia-Dai V, Govrin A, Agam G, Kronfeld-Schor N. Linking type 2 diabetes mellitus, cardiac hypertrophy and depression in a diurnal animal model. Sci Rep 2019; 9:11865. [PMID: 31413352 PMCID: PMC6694156 DOI: 10.1038/s41598-019-48326-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 08/02/2019] [Indexed: 12/28/2022] Open
Abstract
It was recently suggested that the Metabolic Syndrome should be renamed to "Circadian Syndrome". In this context, we explored the effects of living under standard laboratory conditions, where light is the only cycling variable (relevant to human modern life), in a diurnal mammal, on the relationships between affective-like pathology, type 2 diabetes mellitus (T2DM), and cardiac hypertrophy. After 20 weeks, some of the animals spontaneously developed T2DM, depressive and anxiety-like behavior and cardiac hypertrophy. There were significant correlations between levels of anxiety-like behavior and glucose tolerance, and between heart/total body weight ratio and glucose tolerance. Our data suggest a relationship between the development of T2DM, emotional and cardiac pathology as seen in diurnal humans. Furthermore, our data show a possible relationship between reduced daily cycling cues in the laboratory and what has been regularly termed "Metabolic Syndrome" and recently proposed by us to be renamed to "Circadian Syndrome".
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Affiliation(s)
- Carmel Bilu
- School of Zoology, Tel-Aviv University, Tel Aviv, Ramat Aviv, Israel.,Department of Clinical Biochemistry and Pharmacology, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Haim Einat
- Department of Clinical Biochemistry and Pharmacology, Ben-Gurion University of the Negev, Beer Sheva, Israel.,School of Behavioral Sciences, Tel Aviv-Yaffo Academic College, Tel-Aviv, Israel
| | - Orly Barak
- School of Zoology, Tel-Aviv University, Tel Aviv, Ramat Aviv, Israel
| | - Paul Zimmet
- Department of Diabetes, Central Clinical School, Monash University, Melbourne, Australia
| | - Vicktoria Vishnevskia-Dai
- Ocular Oncology and Autoimmune service, The Goldschleger Eye Institute, The Chaim Sheba Medical Center, Tel-Hashomer, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Amanda Govrin
- School of Zoology, Tel-Aviv University, Tel Aviv, Ramat Aviv, Israel
| | - Galila Agam
- Department of Clinical Biochemistry and Pharmacology, Ben-Gurion University of the Negev, Beer Sheva, Israel
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10
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Abstract
The Metabolic Syndrome is a cluster of cardio-metabolic risk factors and comorbidities conveying high risk of both cardiovascular disease and type 2 diabetes. It is responsible for huge socio-economic costs with its resulting morbidity and mortality in most countries. The underlying aetiology of this clustering has been the subject of much debate. More recently, significant interest has focussed on the involvement of the circadian system, a major regulator of almost every aspect of human health and metabolism. The Circadian Syndrome has now been implicated in several chronic diseases including type 2 diabetes and cardiovascular disease. There is now increasing evidence connecting disturbances in circadian rhythm with not only the key components of the Metabolic Syndrome but also its main comorbidities including sleep disturbances, depression, steatohepatitis and cognitive dysfunction. Based on this, we now propose that circadian disruption may be an important underlying aetiological factor for the Metabolic Syndrome and we suggest that it be renamed the 'Circadian Syndrome'. With the increased recognition of the 'Circadian Syndrome', circadian medicine, through the timing of exercise, light exposure, food consumption, dispensing of medications and sleep, is likely to play a much greater role in the maintenance of both individual and population health in the future.
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Affiliation(s)
- P. Zimmet
- Department of DiabetesCentral Clinical SchoolMonash UniversityMelbourneVic.Australia
- Sagol Center for Epigenetics and MetabolismTel Aviv Medical CenterTel AvivIsrael
| | | | - N. Stern
- Sagol Center for Epigenetics and MetabolismTel Aviv Medical CenterTel AvivIsrael
| | - C. Bilu
- School of ZoologyTel Aviv UniversityTel AvivIsrael
| | - A. El‐Osta
- Department of DiabetesCentral Clinical SchoolMonash UniversityMelbourneVic.Australia
- Department of PathologyThe University of MelbourneParkvilleVic.Australia
- Hong Kong Institute of Diabetes and ObesityPrince of Wales HospitalThe Chinese University of Hong KongHong Kong SARChina
| | - H. Einat
- School of Behavioral SciencesTel Aviv‐Yaffo Academic CollegeTel AvivIsrael
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11
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Bilu C, Einat H, Tal-Krivisky K, Mizrahi J, Vishnevskia-Dai V, Agam G, Kronfeld-Schor N. Red white and blue - bright light effects in a diurnal rodent model for seasonal affective disorder. Chronobiol Int 2019; 36:919-926. [PMID: 30983429 DOI: 10.1080/07420528.2019.1595638] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Despite the common use of bright light exposure for treatment of seasonal affective disorder (SAD), the underlying biology of the therapeutic effect is not clear. Moreover, there is a debate regarding the most efficacious wavelength of light for treatment. Whereas according to the traditional approach full-spectrum light is used, recent studies suggest that the critical wavelengths are within the range of blue light (460 and 484 nm). Our previous work shows that when diurnal rodents are maintained under short photoperiod they develop depression- and anxiety-like behavioral phenotype that is ameliorated by treatment with wide-spectrum bright light exposure (2500 lux at the cage, 5000 K). Our current study compares the effect of bright wide-spectrum (3,000 lux, wavelength 420- 780 nm, 5487 K), blue (1,300 lux, wavelength 420-530 nm) and red light (1,300 lux, wavelength range 600-780 nm) exposure in the fat sand rat (Psammomys Obesus) model of SAD. We report results of experiments with six groups of sand rats that were kept under various photoperiods and light treatments, and subjected to behavioral tests related to emotions: forced swim test, elevated plus maze and social interactions. Exposure to either intense wide-spectrum white light or to blue light equally ameliorated depression-like behavior whereas red light had no effect. Bright wide-spectrum white light treatment had no effect on animals maintained under neutral photoperiod, meaning that light exposure was only effective in the pathological-like state. The resemblance between the effects of bright white light and blue light suggests that intrinsically photosensitive retinal ganglion cells (ipRGCs) are involved in the underlying biology of SAD and light therapy.
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Affiliation(s)
- Carmel Bilu
- a School of Zoology , Tel-Aviv University , Tel Aviv , Israel.,b Department of Clinical Biochemistry and Pharmacology , Ben-Gurion University of the Negev , Beer Sheva , Israel
| | - Haim Einat
- c School of Behavioral Sciences , Tel Aviv-Yaffo Academic College , Tel-Aviv , Israel
| | | | - Joseph Mizrahi
- d Department of Medicine , Stony Brook University Hospital , Stony Brook , NY , USA
| | - Vicktoria Vishnevskia-Dai
- e Ocular Oncology and Autoimmune service, The Goldschleger Eye Institute, The Chaim Sheba Medical Center, Tel-Hashomer, Sackler Faculty of Medicine , Tel-Aviv University , Tel Aviv , Israel
| | - Galila Agam
- b Department of Clinical Biochemistry and Pharmacology , Ben-Gurion University of the Negev , Beer Sheva , Israel
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12
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Abstract
Although type 2 diabetes (T2DM) and depression are associated with disturbances in circadian rhythms, most studies of these diseases use nocturnal mice and rats while modeling diurnal humans. We suggest that the development of T2DM and depression are related to changes that accompany the switch from the mammalian ancestral nocturnal activity to the current diurnal one. We show that diurnal sand rats ( Psammomys obesus) held outdoors in laboratory cages (where they are exposed to natural environmental conditions) and fed a standard rodent diet do not develop T2DM in contrast to animals held indoors (where the only cycling environmental condition is light) fed the same diet. Moreover, keeping sand rats under a short photoperiod dampened behavioral and molecular daily rhythms, resulted in anxiety- and depressive-like behavior, and accelerated the development of T2DM. We suggest that the disturbed rhythms disrupt the internal temporal order and metabolic pathways controlled by feeding and the circadian system, resulting in the development of T2DM and depressive-like behavior. We further suggest that using nocturnal mice and rats as sole model animals may limit research, especially when studying circadian rhythm-related diseases.
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Affiliation(s)
- Carmel Bilu
- School of Zoology, Tel-Aviv University, Tel Aviv, Ramat Aviv, Israel.,Department of Clinical Biochemistry and Pharmacology, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Paul Zimmet
- Department of Medicine, Monash University, Melbourne, Victoria, Australia
| | - Vicktoria Vishnevskia-Dai
- Ocular Oncology and Autoimmune service, The Goldschleger Eye Institute, The Chaim Sheba Medical Center, Tel-Hashomer, Sackler Faculty of Medicine, Tel-Aviv University, Israel
| | - Haim Einat
- School of Behavioral Sciences, Tel Aviv-Yaffo Academic College, Tel-Aviv, Israel
| | - Galila Agam
- Department of Clinical Biochemistry and Pharmacology, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Ehud Grossman
- Internal Medicine Department and Hypertension Unit, The Chaim Sheba Medical Center, Tel-Hashomer, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel
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13
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Abstract
Preclinical Research Most neuropsychiatric research, including that related to the circadian system, is performed using nocturnal animals, mainly laboratory mice and rats. Mood disorders are known to be associated with circadian rhythm abnormalities, but the mechanisms by which circadian rhythm disruptions interact with depression remain unclear. As the circadian system of diurnal and nocturnal mammals differs, we previously suggested that the utilization of diurnal animal models may be advantageous for understanding these relations. During the last 10 years, we and others established the validity of several diurnal rodent species as a model for the interactions between circadian rhythms and depression. Diurnal rodents respond to photoperiod manipulation in a similar way to humans, the behavioral outcome is directly related to the circadian system, and treatment that is effective in patients is also effective in the model. Moreover, less effective treatments in patients are also less effective in the model. We, therefore, suggest that using diurnal animal models to study circadian rhythms-related affective disorders, such as depression, will provide new insights that will hopefully lead to the development of more effective treatments. Drug Dev Res 77 : 347-356, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Carmel Bilu
- Department of Zoology Faculty of Life Sciences, Tel-Aviv University, Tel Aviv, Israel.,Faculty of Medicine, Faculty of Health Sciences, Department of Clinical Biochemistry and Pharmacology, Ben-Gurion University of the Negev, Beer, Sheva, Israel
| | - Haim Einat
- School of Behavioral Sciences, Tel Aviv-Yaffo College, Tel Aviv, Israel
| | - Noga Kronfeld-Schor
- Department of Zoology Faculty of Life Sciences, Tel-Aviv University, Tel Aviv, Israel
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14
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Abstract
Animals show daily rhythms in most bodily functions, resulting from the integration of information from an endogenous circadian clock and external stimuli. These rhythms are adaptive and are expected to be related to activity patterns, i.e., to be opposite in diurnal and nocturnal species. Melatonin is secreted during the night in all mammalian species, regardless of their activity patterns. Consequently, in diurnal species the nocturnal secretion of melatonin is concurrent with the resting phase, whereas in nocturnal species it is related to an increase in activity. In this research, we examined in three diurnal and three nocturnal rodent species whether a daily rhythm in anxiety-like behavior exists; whether it differs between nocturnal and diurnal species; and how melatonin affects anxiety-like behavior in species with different activity patterns. Anxiety-like behavior levels were analyzed using the elevated plus-maze. We found a daily rhythm in anxiety-like behavior and a significant response to daytime melatonin administration in all three nocturnal species, which showed significantly lower levels of anxiety during the dark phase, and after melatonin administration. The diurnal species showed either an inverse pattern to that of the nocturnal species in anxiety-like behavior rhythm and in response to daytime melatonin injection, or no rhythm and, accordingly, no response to melatonin.
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Affiliation(s)
- Carmel Bilu
- Department of Zoology, Tel-Aviv University, Tel-Aviv, Israel.
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