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Viskaitis P, Tesmer AL, Liu Z, Karnani MM, Arnold M, Donegan D, Bracey E, Grujic N, Patriarchi T, Peleg-Raibstein D, Burdakov D. Orexin neurons track temporal features of blood glucose in behaving mice. Nat Neurosci 2024; 27:1299-1308. [PMID: 38773350 PMCID: PMC11239495 DOI: 10.1038/s41593-024-01648-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 04/10/2024] [Indexed: 05/23/2024]
Abstract
Does the brain track how fast our blood glucose is changing? Knowing such a rate of change would enable the prediction of an upcoming state and a timelier response to this new state. Hypothalamic arousal-orchestrating hypocretin/orexin neurons (HONs) have been proposed to be glucose sensors, yet whether they track glucose concentration (proportional tracking) or rate of change (derivative tracking) is unknown. Using simultaneous recordings of HONs and blood glucose in behaving male mice, we found that maximal HON responses occur in considerable temporal anticipation (minutes) of glucose peaks due to derivative tracking. Analysis of >900 individual HONs revealed glucose tracking in most HONs (98%), with derivative and proportional trackers working in parallel, and many (65%) HONs multiplexed glucose and locomotion information. Finally, we found that HON activity is important for glucose-evoked locomotor suppression. These findings reveal a temporal dimension of brain glucose sensing and link neurobiological and algorithmic views of blood glucose perception in the brain's arousal orchestrators.
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Affiliation(s)
- Paulius Viskaitis
- Department of Health Sciences and Technology, Swiss Federal Institute of Technology (ETH Zürich), Zurich, Switzerland
| | - Alexander L Tesmer
- Department of Health Sciences and Technology, Swiss Federal Institute of Technology (ETH Zürich), Zurich, Switzerland
| | - Ziyu Liu
- Department of Health Sciences and Technology, Swiss Federal Institute of Technology (ETH Zürich), Zurich, Switzerland
- Department of Neurology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Mahesh M Karnani
- Department of Health Sciences and Technology, Swiss Federal Institute of Technology (ETH Zürich), Zurich, Switzerland
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Myrtha Arnold
- Department of Health Sciences and Technology, Swiss Federal Institute of Technology (ETH Zürich), Zurich, Switzerland
| | - Dane Donegan
- Department of Health Sciences and Technology, Swiss Federal Institute of Technology (ETH Zürich), Zurich, Switzerland
| | - Eva Bracey
- Department of Health Sciences and Technology, Swiss Federal Institute of Technology (ETH Zürich), Zurich, Switzerland
| | - Nikola Grujic
- Department of Health Sciences and Technology, Swiss Federal Institute of Technology (ETH Zürich), Zurich, Switzerland
| | - Tommaso Patriarchi
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Daria Peleg-Raibstein
- Department of Health Sciences and Technology, Swiss Federal Institute of Technology (ETH Zürich), Zurich, Switzerland
| | - Denis Burdakov
- Department of Health Sciences and Technology, Swiss Federal Institute of Technology (ETH Zürich), Zurich, Switzerland.
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Jiao Y, Tong CSW, Zhao L, Zhang Y, Nicholls JM, Rainer TH. Intraperitoneal versus intranasal administration of lipopolysaccharide in causing sepsis severity in a murine model: a preliminary comparison. Lab Anim Res 2024; 40:18. [PMID: 38741131 DOI: 10.1186/s42826-024-00205-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 04/17/2024] [Accepted: 04/28/2024] [Indexed: 05/16/2024] Open
Abstract
Community-acquired respiratory infection is the commonest cause of sepsis presenting to emergency departments. Yet current experimental animal models simulate peritoneal sepsis with intraperitoneal (I.P.) injection of lipopolysaccharide (LPS) as the predominant route. We aimed to compare the progression of organ injury between I.P. LPS and intranasal (I.N.) LPS in order to establish a better endotoxemia murine model of respiratory sepsis. Eight weeks old male BALB/c mice received LPS-Escherichia coli doses at 0.15, 1, 10, 20, 40 and 100 mg per kg body weight (e.g. LPS-10 is a dose of 10 mg/kg body weight). Disease severity was monitored by a modified Mouse Clinical Assessment Score for Sepsis (M-CASS; range 0-21). A M-CASS score ≥ 10 or a weight reduction of ≥ 20%, was used as a criterion for euthanasia. The primary outcome was the survival rate (either no death or no need for euthanasia). The progression of disease was specified as M-CASS, body weight, blood glucose, histopathological changes to lung, liver, spleen, kidney, brain and heart tissues. Survival rate in I.P. LPS-20 mice was 0% (2/3 died; 1/3 euthanized with M-CASS > 10) at 24 h. Survival rate in all doses of I.N. LPS was 100% (20/20; 3-4 per group) at 96 h. 24 h mean M-CASS post-I.P. LPS-10 was 6.4/21 significantly higher than I.N. LPS-10 of 1.7/21 (Unpaired t test, P < 0.05). Organ injury was present at 96 h in the I.P. LPS-10 group: lung (3/3; 100%), spleen (3/3; 100%) and liver (1/3; 33%). At 24 h in the I.P. LPS-20 group, kidney injury was observed in the euthanized mouse. At 96 h in the post-I.N. LPS-20 group, only lung injury was observed in 2/3 (67%) mice (Kruskal-Wallis test with Dunn's, P < 0.01). At 24 h in the post-I.N. LPS-100 group all (4/4) mice had evidence of lung injury. Variable doses of I.N. LPS in mice produced lung injury but did not produce sepsis. Higher doses of I.P. LPS induced multi-organ injury but not respiratory sepsis. Lethal models of respiratory virus, e.g., influenza A, might provide alternative avenues that can be explored in future research.
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Affiliation(s)
- Yaqing Jiao
- Department of Emergency Medicine, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Cindy S W Tong
- Department of Emergency Medicine, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Lingyun Zhao
- Department of Emergency Medicine, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Yilin Zhang
- Department of Emergency Medicine, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - John M Nicholls
- Department of Pathology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Timothy H Rainer
- Department of Emergency Medicine, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
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Alsaedi MK, Riccio RE, Sharma A, Xia J, Owyeung RE, Romero LM, Sonkusale S. Smart sensing flexible sutures for glucose monitoring in house sparrows. Analyst 2023; 148:5714-5723. [PMID: 37840341 DOI: 10.1039/d3an01488f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
There is a need for flexible chemical sensors for the ecological and physiological research of avian species such as house sparrows (Passer domesticus). Current methods in this field are invasive and require multiple physical interactions with the birds. Emerging research in flexible bioelectronics can enable realization of implantable devices that are mechanically compliant with the underlying tissues for continuous real-time sensing in situ. However, challenges still remain in forming an intimate flexible interface. One of the promising flexible bioelectronic platforms for tissue-embedded sensing is based on functionalizing surgical sutures or threads. Threads have three-dimensional flexibility, high surface-area-to-volume ratio, inherent wicking properties, and are easily functionalizable using reel-to-reel dip coating. Threads are ideal as they are lightweight, therefore, would not interfere with flight motion and would only require minimal interaction with the bird. However, the challenge remains in achieving a highly conductive yet flexible electrode for electrochemical sensing using materials such as gold. In this study, we address this issue through novel gold deposition directly on thread substrate followed by enzyme immobilization to realize flexible electrochemical glucose biosensors on medical-grade sutures. These sensors were calibrated and tested in a range that is wide enough to include the expected range of glucose concentration in house sparrows (0-8.55 mM). Glucose monitoring in house sparrows will provide insights into energy metabolism and regulation during stress responses. In addition, the stability, repeatability, and selectivity of the sensor were tested with final validation in a real bird. Our innovative gold-coated, thread-based flexible electrochemical glucose sensor can also be used in other small and large animals. This can also be extended to monitoring other metabolites in future.
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Affiliation(s)
- Mossab K Alsaedi
- Department of Chemical and Biological Engineering, Tufts University, Medford, MA, 02155, USA.
- Nano Lab, Advanced Technology Laboratory, Tufts University, Medford, MA, 02155, USA
| | - Rachel E Riccio
- Nano Lab, Advanced Technology Laboratory, Tufts University, Medford, MA, 02155, USA
- Department of Biology, Tufts University, Medford, MA, 02155, USA
| | - Atul Sharma
- Nano Lab, Advanced Technology Laboratory, Tufts University, Medford, MA, 02155, USA
- Department of Electrical and Computer Engineering, Tufts University, Medford, MA, 02155, USA
| | - Junfei Xia
- Nano Lab, Advanced Technology Laboratory, Tufts University, Medford, MA, 02155, USA
- Department of Electrical and Computer Engineering, Tufts University, Medford, MA, 02155, USA
| | - Rachel E Owyeung
- Nano Lab, Advanced Technology Laboratory, Tufts University, Medford, MA, 02155, USA
- Department of Electrical and Computer Engineering, Tufts University, Medford, MA, 02155, USA
| | - L Michael Romero
- Department of Biology, Tufts University, Medford, MA, 02155, USA
| | - Sameer Sonkusale
- Department of Chemical and Biological Engineering, Tufts University, Medford, MA, 02155, USA.
- Nano Lab, Advanced Technology Laboratory, Tufts University, Medford, MA, 02155, USA
- Department of Electrical and Computer Engineering, Tufts University, Medford, MA, 02155, USA
- Department of Biomedical Engineering, Tufts University, Medford, MA, 02155, USA
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Rubio WB, Cortopassi MD, Ramachandran D, Walker SJ, Balough EM, Wang J, Banks AS. Not so fast: Paradoxically increased variability in the glucose tolerance test due to food withdrawal in continuous glucose-monitored mice. Mol Metab 2023; 77:101795. [PMID: 37640144 PMCID: PMC10493264 DOI: 10.1016/j.molmet.2023.101795] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 08/16/2023] [Accepted: 08/23/2023] [Indexed: 08/31/2023] Open
Abstract
OBJECTIVE This study was performed to determine the effect of fasting on reproducibility of the glucose tolerance test. Due to individual variation in animal feeding behaviors, fasting animals prior to metabolic and behavioral experiments is widely held to reduce inter-subject variation in glucose and metabolic parameters of preclinical rodent models. Reducing variability is especially important for studies where initial metabolite levels can influence the magnitude of experimental interventions, but fasting also imposes stress that may distort the variables of interest. One such intervention is the glucose tolerance test (GTT) which measures the maximum response and recovery following a bolus of exogenous glucose. We sought to investigate how fasting affects the response of individual mice to a GTT. METHODS Using simultaneous continuous glucose monitoring (CGM) and indirect calorimetry, we quantified blood glucose, physical activity, body temperature, metabolic rates, and food consumption levels on a minute-to-minute basis in adult male mice for 4 weeks. We tested the effects of a 4-h or 18-h fast on the GTT to examine the effect of food withdrawal in light or dark photoperiods. Studies were also performed with 4-h fasting in additional mice without implanted CGM probes. RESULTS Contrary to our expectations, a 4-h fast during the light photoperiod promotes a paradoxical increase in inter-animal variation in metabolic rate, physical activity, body temperature, glycemia, and glucose tolerance. This hyperglycemic and hyper-metabolic phenotype promotes increased corticosterone levels and is consistent with a behavioral stress response to food deprivation, even in well-fed mice. We find that mice undergoing an 18-h fast entered torpor, a hibernation-like state. In addition to low body temperature and metabolic rate, torpor is also associated with glucose levels 56 mg/dl lower than those seen in mice with ad libitum access to food. Moreover, the time spent in torpor affects the response to a GTT. CONCLUSION Our results suggest fasting mice before glucose tolerance testing, and perhaps other experiments, can have the opposite of the intended effect where fasting can increase, rather than decrease, experimental variability.
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Affiliation(s)
- William B Rubio
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Marissa D Cortopassi
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Deepti Ramachandran
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Samuel J Walker
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Elizabeth M Balough
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Jiefu Wang
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Alexander S Banks
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.
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Daniell H, Singh R, Mangu V, Nair SK, Wakade G, Balashova N. Affordable oral proinsulin bioencapsulated in plant cells regulates blood sugar levels similar to natural insulin. Biomaterials 2023; 298:122142. [PMID: 37148757 PMCID: PMC10219636 DOI: 10.1016/j.biomaterials.2023.122142] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 04/30/2023] [Accepted: 05/01/2023] [Indexed: 05/08/2023]
Abstract
Diabetes Mellitus is a silent epidemic affecting >500 million, which claimed 6.7 million lives in 2021, a projected increase of >670% in <20 years old in the next two decades but insulin is unaffordable for the large majority of the globe. Therefore, we engineered proinsulin in plant cells to facilitate oral delivery. Stability of the proinsulin gene and expression in subsequent generations, after removal of the antibiotic-resistance gene, was confirmed using PCR, Southern and western blots. Proinsulin expression was high (up to 12 mg/g DW or 47.5% of total leaf protein), stable up to one year after storage of freeze-dried plant cells at ambient temperature and met FDA regulatory requirements of uniformity, moisture content and bioburden. GM1 receptor binding, required for uptake via gut epithelial cells was confirmed by pentameric assembly of CTB-Proinsulin. IP insulin injections (without C peptide) in STZ mice rapidly decreased blood glucose level leading to transient hypoglycemia, followed by hepatic glucose compensation. On the other hand, other than the 15-min lag period of oral proinsulin (transit time required to reach the gut), the kinetics of blood sugar regulation of oral CTB-Proinsulin in STZ mice was very similar to naturally secreted insulin in healthy mice (both contain C-peptide), without rapid decrease or hypoglycemia. Elimination of expensive fermentation, purification and cold storage/transportation should reduce cost and increase other health benefits of plant fibers. The recent approval of plant cell delivery of therapeutic proteins by FDA and approval of CTB-ACE2 for phase I/II human clinical studies augur well for advancing oral proinsulin to the clinic.
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Affiliation(s)
- Henry Daniell
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| | - Rahul Singh
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Venkata Mangu
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Smruti K Nair
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Geetanjali Wakade
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Nataliya Balashova
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Yamamoto JM, Murphy HR. Technology and Pregnancy. Diabetes Technol Ther 2022; 24:S96-S106. [PMID: 35475694 DOI: 10.1089/dia.2022.2506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Jennifer M Yamamoto
- Department of Internal Medicine, University of Manitoba, Canada
- Department of Medicine, University of Calgary, Canada
- Children's Hospital Research Institute of Manitoba, Manitoba, Canada
| | - Helen R Murphy
- Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
- Women's Health Academic Centre, Division of Women's and Children's Health, King's College London, London, UK
- Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, UK
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