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Bao L, Zhao J, Gregersen H. Association between jejunal remodeling in fasting rats and hypersensitivity of intestinal afferent nerves to mechanical stimulation. Biomech Model Mechanobiol 2024; 23:73-86. [PMID: 37548873 DOI: 10.1007/s10237-023-01758-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Accepted: 07/24/2023] [Indexed: 08/08/2023]
Abstract
Remodeling of Intestinal properties and hypersensitivity of intestinal afferents to mechanical stimulation were previously demonstrated in a fasting rat model. Other studies investigated the association between mechanical and histological remodeling during fasting. This study aimed to further explore the relationship between the jejunal remodeling and intestinal afferent hypersensitivity by combining afferent nerve recordings with histological and mechanical data. Eight male Sprague Dawley rats had no access to food for 7 days (Fasting group). Seven male rats served as controls (Control group). Jejunal segments were studied in vitro in an organ bath for analysis of afferent signaling and for analysis of mechanical and histomorphological parameters. Correlation analyses were done to analyze association between nerve activity (spike rate increase ratio, SRIR) at distension levels of 20, 40 and 80 cmH2O and mechanical stress and histomorphological changes of the jejunal segments. Compared with the Control group, the main findings in jejunal segments in the Fasting group were (1) Most histomorphometry parameters were reduced (P < 0.05-P < 0.001), (2) SRIR values were higher (P < 0.001), (3) The relative numbers of intermuscular and submucosal neurons were increased (P < 0.05-P < 0.01), and (4) SRIR was negatively correlated with intestinal wall thickness, circumferential muscle layer thickness and positively correlated with the inner residual strain, the number of neurons, and the mechanical stress. In conclusion, the fasting-induced histomorphological remodeling (reduced wall thickness and increased relative number of neurons) and biomechanical remodeling (residual strain changes and high stress level) of the intestine in fasting rats were associated with hypersensitivity of intestinal afferents. Afferent hypersensitivity appears to be dependent on stress rather than on strain.
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Affiliation(s)
- Lingxia Bao
- Chongqing University of Posts and Telecommunications, Chongqing, 400065, China
- GIOME and the Key Laboratory for Biorheological Science and Technology of Ministry of Education, College of Bioengineering at Chongqing University, Chongqing, 400044, China
| | - Jingbo Zhao
- GIOME and the Key Laboratory for Biorheological Science and Technology of Ministry of Education, College of Bioengineering at Chongqing University, Chongqing, 400044, China.
- Anbiping (Chongqing) Pathological Diagnosis Center, No. 8 Xiyuan North Road, Shapingba District, Chongqing, 401334, China.
| | - Hans Gregersen
- GIOME and the Key Laboratory for Biorheological Science and Technology of Ministry of Education, College of Bioengineering at Chongqing University, Chongqing, 400044, China
- GIOME, California Medical Innovations Institute, San Diego, CA, USA
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Smith JA, Eikenberry SA, Scott KA, Baumer-Harrison C, de Lartigue G, de Kloet AD, Krause EG. Oxytocin and cardiometabolic interoception: Knowing oneself affects ingestive and social behaviors. Appetite 2022; 175:106054. [PMID: 35447163 DOI: 10.1016/j.appet.2022.106054] [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: 01/03/2022] [Revised: 03/22/2022] [Accepted: 04/14/2022] [Indexed: 01/22/2023]
Abstract
Maintaining homeostasis while navigating one's environment involves accurately assessing and interacting with external stimuli while remaining consciously in tune with internal signals such as hunger and thirst. Both atypical social interactions and unhealthy eating patterns emerge as a result of dysregulation in factors that mediate the prioritization and attention to salient stimuli. Oxytocin is an evolutionarily conserved peptide that regulates attention to exteroceptive and interoceptive stimuli in a social environment by functioning in the brain as a modulatory neuropeptide to control social behavior, but also in the periphery as a hormone acting at oxytocin receptors (Oxtr) expressed in the heart, gut, and peripheral ganglia. Specialized sensory afferent nerve endings of Oxtr-expressing nodose ganglia cells transmit cardiometabolic signals via the Vagus nerve to integrative regions in the brain that also express Oxtr(s). These brain regions are influenced by vagal sensory pathways and coordinate with external events such as those demanding attention to social stimuli, thus the sensations related to cardiometabolic function and social interactions are influenced by oxytocin signaling. This review investigates the literature supporting the idea that oxytocin mediates the interoception of cardiovascular and gastrointestinal systems, and that the modulation of this awareness likewise influences social cognition. These concepts are then considered in relation to Autism Spectrum Disorder, exploring how atypical social behavior is comorbid with cardiometabolic dysfunction.
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Affiliation(s)
- Justin A Smith
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, USA; Center for Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, FL, USA; Evelyn F. and William L. McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Sophia A Eikenberry
- Center for Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, FL, USA; Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL, USA; Evelyn F. and William L. McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Karen A Scott
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, USA; Center for Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, FL, USA; Evelyn F. and William L. McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Caitlin Baumer-Harrison
- Center for Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, FL, USA; Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL, USA; Evelyn F. and William L. McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Guillaume de Lartigue
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, USA; Center for Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, FL, USA
| | - Annette D de Kloet
- Center for Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, FL, USA; Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL, USA; Evelyn F. and William L. McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Eric G Krause
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, USA; Center for Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, FL, USA; Evelyn F. and William L. McKnight Brain Institute, University of Florida, Gainesville, FL, USA.
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