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Dixit Y, Kanojiya K, Bhingardeve N, Ahire JJ, Saroj D. In Vitro Human Gastrointestinal Tract Simulation Systems: A Panoramic Review. Probiotics Antimicrob Proteins 2024; 16:501-518. [PMID: 36988898 DOI: 10.1007/s12602-023-10052-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/02/2023] [Indexed: 03/30/2023]
Abstract
Simulated human gastrointestinal (GI) tract systems are important for their applications in the fields of probiotics, nutrition and health. To date, various in vitro gut systems have been available to study GI tract dynamics and its association with health. In contrast to in vivo investigations, which are constrained by ethical considerations, in vitro models have several benefits despite the challenges involved in mimicking the GI environment. These in vitro models can be used for a range of research, from simple to dynamic, with one compartment to several compartments. In this review, we present a panoramic development of in vitro GI models for the first time through an evolutionary timeline. We tried to provide insight on designing an in vitro gut model, especially for novices. Latest developments and scope for improvement based on the limitations of the existing models were highlighted. In conclusion, designing an in vitro GI model suitable for a particular application is a multifaceted task. The bio-mimicking of the GI tract specific to geometrical, anatomical and mechanical features remains a challenge for the development of effective in vitro GI models. Advances in computer technology, artificial intelligence and nanotechnology are going to be revolutionary for further development. Besides this, in silico high-throughput technologies and miniaturisation are key players in the success of making in vitro modelling cost-effective and reducing the burden of in vivo studies.
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Affiliation(s)
- Yogini Dixit
- Advanced Enzyme Technologies Ltd., 5th Floor, A-Wing, Sun Magnetica, Louiswadi, Maharashtra, Thane West, India
| | - Khushboo Kanojiya
- Advanced Enzyme Technologies Ltd., 5th Floor, A-Wing, Sun Magnetica, Louiswadi, Maharashtra, Thane West, India
| | - Namrata Bhingardeve
- Advanced Enzyme Technologies Ltd., 5th Floor, A-Wing, Sun Magnetica, Louiswadi, Maharashtra, Thane West, India
| | - Jayesh J Ahire
- Advanced Enzyme Technologies Ltd., 5th Floor, A-Wing, Sun Magnetica, Louiswadi, Maharashtra, Thane West, India.
| | - Dina Saroj
- Advanced Enzyme Technologies Ltd., 5th Floor, A-Wing, Sun Magnetica, Louiswadi, Maharashtra, Thane West, India
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Athavale ON, Avci R, Clark AR, Di Natale MR, Wang X, Furness JB, Liu Z, Cheng LK, Du P. Neural regulation of slow waves and phasic contractions in the distal stomach: a mathematical model. J Neural Eng 2024; 20:066040. [PMID: 38100816 PMCID: PMC10765034 DOI: 10.1088/1741-2552/ad1610] [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: 07/04/2023] [Revised: 11/06/2023] [Accepted: 12/15/2023] [Indexed: 12/17/2023]
Abstract
Objective.Neural regulation of gastric motility occurs partly through the regulation of gastric bioelectrical slow waves (SWs) and phasic contractions. The interaction of the tissues and organs involved in this regulatory process is complex. We sought to infer the relative importance of cellular mechanisms in inhibitory neural regulation of the stomach by enteric neurons and the interaction of inhibitory and excitatory electrical field stimulation.Approach.A novel mathematical model of gastric motility regulation by enteric neurons was developed and scenarios were simulated to determine the mechanisms through which enteric neural influence is exerted. This model was coupled to revised and extended electrophysiological models of gastric SWs and smooth muscle cells (SMCs).Main results.The mathematical model predicted that regulation of contractile apparatus sensitivity to intracellular calcium in the SMC was the major inhibition mechanism of active tension development, and that the effect on SW amplitude depended on the inhibition of non-specific cation currents more than the inhibition of calcium-activated chloride current (kiNSCC= 0.77 vs kiAno1= 0.33). The model predicted that the interaction between inhibitory and excitatory neural regulation, when applied with simultaneous and equal intensity, resulted in an inhibition of contraction amplitude almost equivalent to that of inhibitory stimulation (79% vs 77% decrease), while the effect on frequency was overall excitatory, though less than excitatory stimulation alone (66% vs 47% increase).Significance.The mathematical model predicts the effects of inhibitory and excitatory enteric neural stimulation on gastric motility function, as well as the effects when inhibitory and excitatory enteric neural stimulation interact. Incorporation of the model into organ-level simulations will provide insights regarding pathological mechanisms that underpin gastric functional disorders, and allow forin silicotesting of the effects of clinical neuromodulation protocols for the treatment of these disorders.
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Affiliation(s)
- Omkar N Athavale
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Recep Avci
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Alys R Clark
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Madeleine R Di Natale
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
- Department of Anatomy & Physiology, University of Melbourne, Parkville, VIC, Australia
| | - Xiaokai Wang
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America
| | - John B Furness
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
- Department of Anatomy & Physiology, University of Melbourne, Parkville, VIC, Australia
| | - Zhongming Liu
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America
| | - Leo K Cheng
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Peng Du
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
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Madyarov V, Kuzikeev M, Malgazhdarov M, Abzalbek Y, Ashimov G. A forecasting method of postoperative intestinal paralysis and its timely resolution. PRZEGLAD GASTROENTEROLOGICZNY 2023; 18:393-401. [PMID: 38572460 PMCID: PMC10985748 DOI: 10.5114/pg.2023.133063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 08/17/2022] [Indexed: 04/05/2024]
Abstract
Introduction The development of intestinal paresis after surgery in patients with acute surgical conditions complicated by peritonitis is an urgent problem of abdominal surgery. Aim To study the effectiveness of the developed methods, as well as to predict the risk of intestinal paresis, and establish the possibilities of correcting this condition in patients with acute surgical pathology complicated by peritonitis. Material and methods Twenty patients were examined, in whom the temperature parameters of the mucous membrane and skin of the cheek were measured, based on which the probability of developing paresis was predicted. Results The proposed method of thermometry of the mucous membrane and cheek skin made it possible to predict a high risk of intestinal paresis in 75% of patients and low risk in 25% of patients. It was shown that 80% of patients had a complete restoration of intestinal motility on the first day after the start of treatment. In 20% of cases, a partial improvement in the motor evacuation function of the intestine was observed on the first day, and full recovery was noted on the second day after the start of therapy. Conclusions The developed methods are highly effective and suitable for predicting and correcting intestinal paresis in patients with acute surgical conditions in the postoperative period.
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Affiliation(s)
- Valentin Madyarov
- Department of Surgeons with Anaesthesiology and Intensive Care, Kazakh-Russian Medical University, Almaty, Republic of Kazakhstan
| | - Marat Kuzikeev
- Department of Surgeons with Anaesthesiology and Intensive Care, Kazakh-Russian Medical University, Almaty, Republic of Kazakhstan
| | - Maulen Malgazhdarov
- Department of Surgeons with Anaesthesiology and Intensive Care, Kazakh-Russian Medical University, Almaty, Republic of Kazakhstan
| | - Yestay Abzalbek
- Department of Oncology, Central Clinical Hospital, Almaty, Republic of Kazakhstan
| | - Gulmamed Ashimov
- Surgical Department, Medical Centre Rahat, Almaty, Republic of Kazakhstan
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Athavale ON, Avci R, Cheng LK, Du P. Computational models of autonomic regulation in gastric motility: Progress, challenges, and future directions. Front Neurosci 2023; 17:1146097. [PMID: 37008202 PMCID: PMC10050371 DOI: 10.3389/fnins.2023.1146097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 02/27/2023] [Indexed: 03/17/2023] Open
Abstract
The stomach is extensively innervated by the vagus nerve and the enteric nervous system. The mechanisms through which this innervation affects gastric motility are being unraveled, motivating the first concerted steps towards the incorporation autonomic regulation into computational models of gastric motility. Computational modeling has been valuable in advancing clinical treatment of other organs, such as the heart. However, to date, computational models of gastric motility have made simplifying assumptions about the link between gastric electrophysiology and motility. Advances in experimental neuroscience mean that these assumptions can be reviewed, and detailed models of autonomic regulation can be incorporated into computational models. This review covers these advances, as well as a vision for the utility of computational models of gastric motility. Diseases of the nervous system, such as Parkinson’s disease, can originate from the brain-gut axis and result in pathological gastric motility. Computational models are a valuable tool for understanding the mechanisms of disease and how treatment may affect gastric motility. This review also covers recent advances in experimental neuroscience that are fundamental to the development of physiology-driven computational models. A vision for the future of computational modeling of gastric motility is proposed and modeling approaches employed for existing mathematical models of autonomic regulation of other gastrointestinal organs and other organ systems are discussed.
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Ahmed MA, Venugopal S, Jung R. Engaging biological oscillators through second messenger pathways permits emergence of a robust gastric slow-wave during peristalsis. PLoS Comput Biol 2021; 17:e1009644. [PMID: 34871315 PMCID: PMC8675931 DOI: 10.1371/journal.pcbi.1009644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 12/16/2021] [Accepted: 11/15/2021] [Indexed: 11/19/2022] Open
Abstract
Peristalsis, the coordinated contraction—relaxation of the muscles of the stomach is important for normal gastric motility and is impaired in motility disorders. Coordinated electrical depolarizations that originate and propagate within a network of interconnected layers of interstitial cells of Cajal (ICC) and smooth muscle (SM) cells of the stomach wall as a slow-wave, underly peristalsis. Normally, the gastric slow-wave oscillates with a single period and uniform rostrocaudal lag, exhibiting network entrainment. Understanding of the integrative role of neurotransmission and intercellular coupling in the propagation of an entrained gastric slow-wave, important for understanding motility disorders, however, remains incomplete. Using a computational framework constituted of a novel gastric motility network (GMN) model we address the hypothesis that engaging biological oscillators (i.e., ICCs) by constitutive gap junction coupling mechanisms and enteric neural innervation activated signals can confer a robust entrained gastric slow-wave. We demonstrate that while a decreasing enteric neural innervation gradient that modulates the intracellular IP3 concentration in the ICCs can guide the aboral slow-wave propagation essential for peristalsis, engaging ICCs by recruiting the exchange of second messengers (inositol trisphosphate (IP3) and Ca2+) ensures a robust entrained longitudinal slow-wave, even in the presence of biological variability in electrical coupling strengths. Our GMN with the distinct intercellular coupling in conjunction with the intracellular feedback pathways and a rostrocaudal enteric neural innervation gradient allows gastric slow waves to oscillate with a moderate range of frequencies and to propagate with a broad range of velocities, thus preventing decoupling observed in motility disorders. Overall, the findings provide a mechanistic explanation for the emergence of decoupled slow waves associated with motility impairments of the stomach, offer directions for future experiments and theoretical work, and can potentially aid in the design of new interventional pharmacological and neuromodulation device treatments for addressing gastric motility disorders. The coordinated contraction and relaxation of the muscles of the stomach, known as peristalsis is important for normal gastric motility and primarily governed by electrical depolarizations that originate and propagate within a network of interconnected layers of interstitial cells of Cajal (ICCs) and smooth muscle cells of the stomach wall as a slow-wave. Under normal conditions, a gastric slow-wave oscillates with a single period and uniform rostrocaudal lag, exhibiting network entrainment. However, the understanding of intrinsic and extrinsic mechanisms that ensure propagation of a robust entrained slow-wave remains incomplete. Here, using a computational framework, we show that in conjunction with an enteric neural innervation gradient along the rostrocaudal ICC chain, and intercellular electrical coupling, the intercellular exchange of inositol trisphosphate between ICCs prevents decoupling by extending the longitudinal entrainment range along the stomach wall, even when variability in intercellular coupling exists. The findings from our study indicate ways that ensure the rostrocaudal spread of a robust gastric slow-wave and provide a mechanistic explanation for the emergence of decoupled slow waves associated with motility impairments of the stomach.
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Affiliation(s)
- Md Ashfaq Ahmed
- Department of Biomedical Engineering, Florida International University, Miami, Florida, United States of America
| | - Sharmila Venugopal
- Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail: (SV); (RJ)
| | - Ranu Jung
- Department of Biomedical Engineering, Florida International University, Miami, Florida, United States of America
- * E-mail: (SV); (RJ)
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Garrett A, Rakhilin N, Wang N, McKey J, Cofer G, Anderson RB, Capel B, Johnson GA, Shen X. Mapping the peripheral nervous system in the whole mouse via compressed sensing tractography. J Neural Eng 2021; 18. [PMID: 33979784 DOI: 10.1088/1741-2552/ac0089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 05/12/2021] [Indexed: 11/12/2022]
Abstract
Objective.The peripheral nervous system (PNS) connects the central nervous system with the rest of the body to regulate many physiological functions and is therapeutically targeted to treat diseases such as epilepsy, depression, intestinal dysmotility, chronic pain, and more. However, we still lack understanding of PNS innervation in most organs because the large span, diffuse nature, and small terminal nerve bundle fibers have precluded whole-organism, high resolution mapping of the PNS. We sought to produce a comprehensive peripheral nerve atlas for use in future interrogation of neural circuitry and selection of targets for neuromodulation.Approach.We used diffusion tensor magnetic resonance imaging (DT-MRI) with high-speed compressed sensing to generate a tractogram of the whole mouse PNS. The tractography generated from the DT-MRI data is validated using lightsheet microscopy on optically cleared, antibody stained tissue.Main results.Herein we demonstrate the first comprehensive PNS tractography in a whole mouse. Using this technique, we scanned the whole mouse in 28 h and mapped PNS innervation and fiber network in multiple organs including heart, lung, liver, kidneys, stomach, intestines, and bladder at 70µm resolution. This whole-body PNS tractography map has provided unparalleled information; for example, it delineates the innervation along the gastrointestinal tract by multiple sacral levels and by the vagal nerves. The map enabled a quantitative tractogram that revealed relative innervation of the major organs by each vertebral foramen as well as the vagus nerve.Significance.This novel high-resolution nerve atlas provides a potential roadmap for future neuromodulation therapies and other investigations into the neural circuits which drive homeostasis and disease throughout the body.
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Affiliation(s)
- Aliesha Garrett
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, United States of America
| | - Nikolai Rakhilin
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, United States of America
| | - Nian Wang
- Duke Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, United States of America
| | - Jennifer McKey
- Department of Cell Biology, School of Medicine, Duke University, Durham, NC, United States of America
| | - Gary Cofer
- Duke Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, United States of America
| | - Robert Bj Anderson
- Duke Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, United States of America
| | - Blanche Capel
- Department of Cell Biology, School of Medicine, Duke University, Durham, NC, United States of America
| | - G Allan Johnson
- Duke Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, United States of America
| | - Xiling Shen
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, United States of America
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Cheng LK, Nagahawatte ND, Avci R, Du P, Liu Z, Paskaranandavadivel N. Strategies to Refine Gastric Stimulation and Pacing Protocols: Experimental and Modeling Approaches. Front Neurosci 2021; 15:645472. [PMID: 33967679 PMCID: PMC8100207 DOI: 10.3389/fnins.2021.645472] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 03/22/2021] [Indexed: 12/13/2022] Open
Abstract
Gastric pacing and stimulation strategies were first proposed in the 1960s to treat motility disorders. However, there has been relatively limited clinical translation of these techniques. Experimental investigations have been critical in advancing our understanding of the control mechanisms that innervate gut function. In this review, we will discuss the use of pacing to modulate the rhythmic slow wave conduction patterns generated by interstitial cells of Cajal in the gastric musculature. In addition, the use of gastric high-frequency stimulation methods that target nerves in the stomach to either inhibit or enhance stomach function will be discussed. Pacing and stimulation protocols to modulate gastric activity, effective parameters and limitations in the existing studies are summarized. Mathematical models are useful to understand complex and dynamic systems. A review of existing mathematical models and techniques that aim to help refine pacing and stimulation protocols are provided. Finally, some future directions and challenges that should be investigated are discussed.
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Affiliation(s)
- Leo K Cheng
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.,Department of General Surgery, Vanderbilt University Medical Center, Nashville, TN, United States.,Riddet Institute, Palmerston North, New Zealand
| | - Nipuni D Nagahawatte
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Recep Avci
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Peng Du
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Zhongming Liu
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States.,Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, United States
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Barth BB, Travis L, Spencer NJ, Grill WM. Control of colonic motility using electrical stimulation to modulate enteric neural activity. Am J Physiol Gastrointest Liver Physiol 2021; 320:G675-G687. [PMID: 33624530 PMCID: PMC8238160 DOI: 10.1152/ajpgi.00463.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 02/11/2021] [Accepted: 02/11/2021] [Indexed: 01/31/2023]
Abstract
Electrical stimulation of the enteric nervous system (ENS) is an attractive approach to modify gastrointestinal transit. Colonic motor complexes (CMCs) occur with a periodic rhythm, but the ability to elicit a premature CMC depends, at least in part, upon the intrinsic refractory properties of the ENS, which are presently unknown. The objectives of this study were to record myoelectric complexes (MCs, the electrical correlates of CMCs) in the smooth muscle and 1) determine the refractory periods of MCs, 2) inform and evaluate closed-loop stimulation to repetitively evoke MCs, and 3) identify stimulation methods to suppress MC propagation. We dissected the colon from male and female C57BL/6 mice, preserving the integrity of intrinsic circuitry while removing the extrinsic nerves, and measured properties of spontaneous and evoked MCs in vitro. Hexamethonium abolished spontaneous and evoked MCs, confirming the necessary involvement of the ENS for electrically evoked MCs. Electrical stimulation reduced the mean interval between evoked and spontaneous CMCs (24.6 ± 3.5 vs. 70.6 ± 15.7 s, P = 0.0002, n = 7). The absolute refractory period was 4.3 s (95% confidence interval (CI) = 2.8-5.7 s, R2 = 0.7315, n = 8). Electrical stimulation applied during fluid distention-evoked MCs led to an arrest of MC propagation, and following stimulation, MC propagation resumed at an increased velocity (n = 9). The timing parameters of electrical stimulation increased the rate of evoked MCs and the duration of entrainment of MCs, and the refractory period provides insight into timing considerations for designing neuromodulation strategies to treat colonic dysmotility.NEW & NOTEWORTHY Maintained physiological distension of the isolated mouse colon induces rhythmic cyclic myoelectric complexes (MCs). MCs evoked repeatedly by closed-loop electrical stimulation entrain MCs more frequently than spontaneously occurring MCs. Electrical stimulation delivered at the onset of a contraction temporarily suppresses the propagation of MC contractions. Controlled electrical stimulation can either evoke MCs or temporarily delay MCs in the isolated mouse colon, depending on timing relative to ongoing activity.
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Affiliation(s)
- Bradley B Barth
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
| | - Lee Travis
- Visceral Neurophysiology Laboratory, College of Medicine and Public Health, Centre for Neuroscience, Flinders University, Adelaide, South Australia, Australia
| | - Nick J Spencer
- Visceral Neurophysiology Laboratory, College of Medicine and Public Health, Centre for Neuroscience, Flinders University, Adelaide, South Australia, Australia
| | - Warren M Grill
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina
- Department of Neurobiology, Duke University, Durham, North Carolina
- Department of Neurosurgery, Duke University, Durham, North Carolina
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9
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Ramadi KB, Srinivasan SS, Traverso G. Electroceuticals in the Gastrointestinal Tract. Trends Pharmacol Sci 2020; 41:960-976. [PMID: 33127099 PMCID: PMC8186669 DOI: 10.1016/j.tips.2020.09.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 09/25/2020] [Accepted: 09/30/2020] [Indexed: 02/08/2023]
Abstract
The field of electroceuticals has attracted considerable attention over the past few decades as a novel therapeutic modality. The gastrointestinal (GI) tract (GIT) holds significant potential as a target for electroceuticals as the intersection of neural, endocrine, and immune systems. We review recent developments in electrical stimulation of various portions of the GIT (including esophagus, stomach, and small and large intestine) and nerves projecting to the GIT and supportive organs. This has been tested with varying degrees of success for several dysmotility, inflammatory, hormonal, and neurologic disorders. We outline a vision for the future of GI electroceuticals, building on advances in mechanistic understanding of GI physiology coupled with novel ingestible technologies. The next wave of electroceutical therapies will be minimally invasive and more targeted than current approaches, making them an indispensable tool in the clinical armamentarium.
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Affiliation(s)
- Khalil B Ramadi
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Division of Gastroenterology, Hepatology and Endoscopy, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Shriya S Srinivasan
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Division of Gastroenterology, Hepatology and Endoscopy, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Giovanni Traverso
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Division of Gastroenterology, Hepatology and Endoscopy, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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Opportunities and Challenges for Single-Unit Recordings from Enteric Neurons in Awake Animals. MICROMACHINES 2018; 9:mi9090428. [PMID: 30424361 PMCID: PMC6187697 DOI: 10.3390/mi9090428] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 08/17/2018] [Accepted: 08/23/2018] [Indexed: 12/18/2022]
Abstract
Advanced electrode designs have made single-unit neural recordings commonplace in modern neuroscience research. However, single-unit resolution remains out of reach for the intrinsic neurons of the gastrointestinal system. Single-unit recordings of the enteric (gut) nervous system have been conducted in anesthetized animal models and excised tissue, but there is a large physiological gap between awake and anesthetized animals, particularly for the enteric nervous system. Here, we describe the opportunity for advancing enteric neuroscience offered by single-unit recording capabilities in awake animals. We highlight the primary challenges to microelectrodes in the gastrointestinal system including structural, physiological, and signal quality challenges, and we provide design criteria recommendations for enteric microelectrodes.
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11
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Barth BB, Shen X. Computational motility models of neurogastroenterology and neuromodulation. Brain Res 2018; 1693:174-179. [PMID: 29903620 PMCID: PMC6671680 DOI: 10.1016/j.brainres.2018.02.038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 01/18/2018] [Accepted: 02/24/2018] [Indexed: 01/15/2023]
Abstract
The success of neuromodulation therapies, particularly in the brain, spinal cord, and peripheral nerves, has been greatly aided by computational, biophysical models. However, treating gastrointestinal disorders with electrical stimulation has been much less explored, partly because the mode of action of such treatments is unclear, and selection of stimulation parameters is often empirical. Progress in gut neuromodulation is limited by the comparative lack of biophysical models capable of simulating neuromodulation of gastrointestinal function. Here, we review the recently developed biophysical models of electrically-active cells in the gastrointestinal system that contribute to motility. Biophysical models are replacing phenomenologically-defined models due to advancements in electrophysiological characterization of key players in the gut: enteric neurons, smooth muscle fibers, and interstitial cells of Cajal. In this review, we explore existing biophysically-defined cellular and network models that contribute to gastrointestinal motility. We focus on recent models that are laying the groundwork for modeling electrical stimulation of the gastrointestinal system. Developing models of gut neuromodulation will improve our mechanistic understanding of these treatments, leading to better parameterization, selectivity, and efficacy of neuromodulation to treat gastrointestinal disorders. Such models may have direct clinical translation to current neuromodulation therapies, such as sacral nerve stimulation.
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Affiliation(s)
- Bradley B Barth
- Department of Biomedical Engineering, Duke University, Room 2141, CIEMAS, 101 Science Drive, Durham, NC, USA.
| | - Xiling Shen
- Department of Biomedical Engineering, Duke University, Room 2167, CIEMAS, 101 Science Drive, Durham, NC, USA.
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12
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Mulugeta L, Drach A, Erdemir A, Hunt CA, Horner M, Ku JP, Myers JG, Vadigepalli R, Lytton WW. Credibility, Replicability, and Reproducibility in Simulation for Biomedicine and Clinical Applications in Neuroscience. Front Neuroinform 2018; 12:18. [PMID: 29713272 PMCID: PMC5911506 DOI: 10.3389/fninf.2018.00018] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 03/29/2018] [Indexed: 12/27/2022] Open
Abstract
Modeling and simulation in computational neuroscience is currently a research enterprise to better understand neural systems. It is not yet directly applicable to the problems of patients with brain disease. To be used for clinical applications, there must not only be considerable progress in the field but also a concerted effort to use best practices in order to demonstrate model credibility to regulatory bodies, to clinics and hospitals, to doctors, and to patients. In doing this for neuroscience, we can learn lessons from long-standing practices in other areas of simulation (aircraft, computer chips), from software engineering, and from other biomedical disciplines. In this manuscript, we introduce some basic concepts that will be important in the development of credible clinical neuroscience models: reproducibility and replicability; verification and validation; model configuration; and procedures and processes for credible mechanistic multiscale modeling. We also discuss how garnering strong community involvement can promote model credibility. Finally, in addition to direct usage with patients, we note the potential for simulation usage in the area of Simulation-Based Medical Education, an area which to date has been primarily reliant on physical models (mannequins) and scenario-based simulations rather than on numerical simulations.
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Affiliation(s)
| | - Andrew Drach
- The Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, TX, United States
| | - Ahmet Erdemir
- Department of Biomedical Engineering and Computational Biomodeling (CoBi) Core, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - C A Hunt
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, United States
| | | | - Joy P Ku
- Department of Bioengineering, Stanford University, Stanford, CA, United States
| | - Jerry G Myers
- NASA Glenn Research Center, Cleveland, OH, United States
| | - Rajanikanth Vadigepalli
- Department of Pathology, Anatomy and Cell Biology, Daniel Baugh Institute for Functional Genomics and Computational Biology, Thomas Jefferson University, Philadelphia, PA, United States
| | - William W Lytton
- Department of Neurology, SUNY Downstate Medical Center, The State University of New York, New York, NY, United States.,Department of Physiology and Pharmacology, SUNY Downstate Medical Center, The State University of New York, New York, NY, United States.,Department of Neurology, Kings County Hospital Center, New York, NY, United States
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