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Wang S, Wang Y, Lin L, Li Z, Liu F, Zhu L, Chen J, Zhang N, Cao X, Ran S, Liu G, Gao P, Sun W, Peng L, Zhuang J, Meng H. Layer-Specific BTX-A Delivery to the Gastric Muscularis Achieves Effective Weight Control and Metabolic Improvement. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2300822. [PMID: 37552813 PMCID: PMC10558648 DOI: 10.1002/advs.202300822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 07/03/2023] [Indexed: 08/10/2023]
Abstract
The rising incidence of health-endangering obesity constantly calls for more effective treatments. Gastric intramural injection of botulinum neurotoxin A (BTX-A) as a new modality carries great promise yet inconsistent therapeutic efficacy. A layer-specific delivery strategy enabled by dissolving microneedles is hence pioneered to investigate the working site of BTX-A and the resulting therapeutic effects. The drug-loaded tips of the layer-specific gastric paralysis microneedles (LGP-MN) rapidly release and achieve uniform distribution of BTX-A within the designated gastric wall layers. In an obesity rat model, the LGP-MNs not only prove safer than conventional injection, but also demonstrate consistently better therapeutic effects with muscular layer delivery, including 16.23% weight loss (3.06-fold enhancement from conventional injection), 55.20% slower gastric emptying rate, improved liver steatosis, lowered blood lipids, and healthier gut microbiota. Further hormonal study reveals that the elevated production of stomach-derived glucagon-like peptide-1 due to the muscularis-targeting LGP-MN treatment is an important contributor to its unique glucose tolerance-improving effect. This study provides clear indication of the gastric muscularis as the most favorable working site of BTX-A for weight loss and metabolic improvement purposes, and meanwhile suggests that the LGP-MNs could serve as a novel clinical approach to treat obesity and metabolic syndromes.
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Affiliation(s)
- Siqi Wang
- Department of General Surgery and Obesity and Metabolic Disease CenterChina–Japan Friendship HospitalBeijing100029China
| | - Yuqiong Wang
- Department of Mechanical and Automation EngineeringThe Chinese University of HongkongHongkong999077China
- School of Biological Science and Medical EngineeringBeihang UniversityBeijing100191China
| | - Long Lin
- Engineering College of Peking UniversityPeking universityBeijing100029China
- School of Mechanical and Electrical EngineeringBeijing University of Chemical TechnologyBeijing100029China
| | - Zongjie Li
- Shanghai Veterinary Research InstituteChinese Academy of Agricultural ScienceShanghai200241China
| | - Fengyi Liu
- School of Mechanical and Electrical EngineeringBeijing University of Chemical TechnologyBeijing100029China
| | - Long Zhu
- School of Mechanical and Electrical EngineeringBeijing University of Chemical TechnologyBeijing100029China
| | - Jie Chen
- Department of UltrasoundChina–Japan Friendship HospitalBeijing100029China
| | - Nianrong Zhang
- Department of General Surgery and Obesity and Metabolic Disease CenterChina–Japan Friendship HospitalBeijing100029China
| | - Xinyu Cao
- Department of General Surgery and Obesity and Metabolic Disease CenterChina–Japan Friendship HospitalBeijing100029China
| | - Sunman Ran
- Department of General Surgery and Obesity and Metabolic Disease CenterChina–Japan Friendship HospitalBeijing100029China
| | - Genzheng Liu
- Department of General Surgery and Obesity and Metabolic Disease CenterChina–Japan Friendship HospitalBeijing100029China
| | - Peng Gao
- Department of Clinical LaboratoryChina–Japan Friendship HospitalBeijing100029China
| | - Weiliang Sun
- Institute of Clinical Medical SciencesChina–Japan Friendship HospitalBeijing100029China
| | - Liang Peng
- Institute of Clinical Medical SciencesChina–Japan Friendship HospitalBeijing100029China
| | - Jian Zhuang
- School of Mechanical and Electrical EngineeringBeijing University of Chemical TechnologyBeijing100029China
| | - Hua Meng
- Department of General Surgery and Obesity and Metabolic Disease CenterChina–Japan Friendship HospitalBeijing100029China
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Managing motility disorders of the gastrointestinal segment and obesity through electrical stimulation. HEALTH AND TECHNOLOGY 2021. [DOI: 10.1007/s12553-021-00590-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Penfold JA, Wells CI, Du P, Qian A, Vather R, Bissett IP, O'Grady G. Relationships between serum electrolyte concentrations and ileus: A joint clinical and mathematical modeling study. Physiol Rep 2021; 9:e14735. [PMID: 33527737 PMCID: PMC7851429 DOI: 10.14814/phy2.14735] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 12/30/2020] [Accepted: 01/03/2021] [Indexed: 12/15/2022] Open
Abstract
Aim Prolonged postoperative ileus (PPOI) occurs in around 15% of patients after major abdominal surgery, posing a significant clinical and economic burden. Significant fluid and electrolyte changes may occur peri‐operatively, potentially contributing to PPOI; however, this association has not been clearly elucidated. A joint clinical‐theoretical study was undertaken to evaluate peri‐operative electrolyte concentration trends, their association with ileus, and predicted impact on bioelectrical slow waves in interstitial cells of Cajal (ICC) and smooth muscle cells (SMC). Methods Data were prospectively collected from 327 patients undergoing elective colorectal surgery. Analyses were performed to determine associations between peri‐operative electrolyte concentrations and prolonged ileus. Biophysically based ICC and SMC mathematical models were adapted to evaluate the theoretical impacts of extracellular electrolyte concentrations on cellular function. Results Postoperative day (POD) 1 calcium and POD 3 chloride, sodium were lower in the PPOI group (p < 0.05), and POD3 potassium was higher in the PPOI group (p < 0.05). Deficits beyond the reference range in PPOI patients were most notable for sodium (Day 3: 29.5% ileus vs. 18.5% no ileus, p = 0.04). Models demonstrated an 8.6% reduction in slow‐wave frequency following the measured reduction in extracellular NaCl on POD5, with associated changes in cellular slow‐wave morphology and amplitude. Conclusion Low serum sodium and chloride concentrations are associated with PPOI. Electrolyte abnormalities are unlikely to be a primary mechanism of ileus, but their pronounced effects on cellular electrophysiology predicted by modeling suggest these abnormalities may adversely impact motility recovery. Resolution and correction of electrolyte abnormalities in ileus may be clinically relevant.
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Affiliation(s)
- James A Penfold
- Department of Surgery, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Cameron I Wells
- Department of Surgery, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Peng Du
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Anna Qian
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Ryash Vather
- Department of Surgery, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Ian P Bissett
- Department of Surgery, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.,Department of Surgery, Auckland District Health Board, Auckland, New Zealand
| | - Gregory O'Grady
- Department of Surgery, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.,Department of Surgery, Auckland District Health Board, Auckland, New Zealand.,Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
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Kim SH, Kim HB, Chun HJ, Choi HS, Kim ES, Keum B, Seo YS, Jeen YT, Lee HS, Um SH, Kim CD. Minimally Invasive Gastric Electrical Stimulation Using a Newly Developed Wireless Gastrostimulator: A Pilot Animal Study. J Neurogastroenterol Motil 2020; 26:410-416. [PMID: 32606261 PMCID: PMC7329147 DOI: 10.5056/jnm20063] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 04/25/2020] [Accepted: 05/10/2020] [Indexed: 12/16/2022] Open
Abstract
Background/Aims Gastric electrical stimulation (GES) is a feasible modality for the treatment of gastroparesis; however, the presently available device requires invasive surgical implantation for long-term stimulation and repeated surgical procedure after a period of time. This study is aimed at developing a wireless miniature GES device and testing its endoscopic insertion in animal models. Methods Endoscopic gastric implantation of the GES device was performed on 5 healthy weaner pigs under general anesthesia. We created an endoscopic submucosal pocket and inserted the gastro-electrical stimulator. In vivo gastric slow waves were recorded and measured during electrical stimulation. A multi-channel recorder, called an electrogastrogram, was used to record the gastric myoelectrical activity in the study. Results The gastric slow waves on the electrogastrogram were more consistent with GES on the gastric tissues compared to no stimulation. The frequency-to-amplitude ratio was also significantly altered after the electrical stimulation. Conclusions GES is feasible with our minimally invasive wireless device. This technique has the potential to increase utilization of GES as a treatment alternative.
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Affiliation(s)
- Seung Han Kim
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Institute of Gastrointestinal Medical Instrument Research, Korea University College of Medicine, Seoul, Korea
| | - Hong Bae Kim
- Department of Biosystems and Biomaterials Science and Engineering, Seoul National University, Seoul, Korea
| | - Hoon Jai Chun
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Institute of Gastrointestinal Medical Instrument Research, Korea University College of Medicine, Seoul, Korea
| | - Hyuk Soon Choi
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Institute of Gastrointestinal Medical Instrument Research, Korea University College of Medicine, Seoul, Korea
| | - Eun Sun Kim
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Institute of Gastrointestinal Medical Instrument Research, Korea University College of Medicine, Seoul, Korea
| | - Bora Keum
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Institute of Gastrointestinal Medical Instrument Research, Korea University College of Medicine, Seoul, Korea
| | - Yeon Seok Seo
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Institute of Gastrointestinal Medical Instrument Research, Korea University College of Medicine, Seoul, Korea
| | - Yoon Tae Jeen
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Institute of Gastrointestinal Medical Instrument Research, Korea University College of Medicine, Seoul, Korea
| | - Hong Sik Lee
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Institute of Gastrointestinal Medical Instrument Research, Korea University College of Medicine, Seoul, Korea
| | - Soon Ho Um
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Institute of Gastrointestinal Medical Instrument Research, Korea University College of Medicine, Seoul, Korea
| | - Chang Duck Kim
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Institute of Gastrointestinal Medical Instrument Research, Korea University College of Medicine, Seoul, Korea
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Paskaranandavadivel N, Cheng LK, Du P, Rogers JM, O'Grady G. High-resolution mapping of gastric slow-wave recovery profiles: biophysical model, methodology, and demonstration of applications. Am J Physiol Gastrointest Liver Physiol 2017; 313:G265-G276. [PMID: 28546283 DOI: 10.1152/ajpgi.00127.2017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 05/24/2017] [Accepted: 05/24/2017] [Indexed: 01/31/2023]
Abstract
Slow waves play a central role in coordinating gastric motor activity. High-resolution mapping of extracellular potentials from the stomach provides spatiotemporal detail on normal and dysrhythmic slow-wave patterns. All mapping studies to date have focused exclusively on tissue activation; however, the recovery phase contains vital information on repolarization heterogeneity, the excitable gap, and refractory tail interactions but has not been investigated. Here, we report a method to identify the recovery phase in slow-wave mapping data. We first developed a mathematical model of unipolar extracellular potentials that result from slow-wave propagation. These simulations showed that tissue repolarization in such a signal is defined by the steepest upstroke beyond the activation phase (activation was defined by accepted convention as the steepest downstroke). Next, we mapped slow-wave propagation in anesthetized pigs by recording unipolar extracellular potentials from a high-resolution array of electrodes on the serosal surface. Following the simulation result, a wavelet transform technique was applied to detect repolarization in each signal by finding the maximum positive slope beyond activation. Activation-recovery (ARi) and recovery-activation (RAi) intervals were then computed. We hypothesized that these measurements of recovery profile would differ for slow waves recorded during normal and spatially dysrhythmic propagation. We found that the ARi of normal activity was greater than dysrhythmic activity (5.1 ± 0.8 vs. 3.8 ± 0.7 s; P < 0.05), whereas RAi was lower (9.7 ± 1.3 vs. 12.2 ± 2.5 s; P < 0.05). During normal propagation, RAi and ARi were linearly related with negative unit slope indicating entrainment of the entire mapped region. This relationship was weakened during dysrhythmia (slope: -0.96 ± 0.2 vs -0.71 ± 0.3; P < 0.05).NEW & NOTEWORTHY The theoretical basis of the extracellular gastric slow-wave recovery phase was defined using mathematical modeling. A novel technique utilizing the wavelet transform was developed and validated to detect the extracellular slow-wave recovery phase. In dysrhythmic wavefronts, the activation-to-recovery interval (ARi) was shorter and recovery-to-activation interval (RAi) was longer compared with normal wavefronts. During normal activation, RAi vs. ARi had a slope of -1, whereas the weakening of the slope indicated a dysrhythmic propagation.
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Affiliation(s)
- N Paskaranandavadivel
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand; .,Department of Surgery, University of Auckland, Auckland, New Zealand
| | - L K Cheng
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.,Department of Surgery, Vanderbilt University, Nashville, Tennessee; and
| | - P Du
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - J M Rogers
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, Alabama
| | - G O'Grady
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.,Department of Surgery, University of Auckland, Auckland, New Zealand
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