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Larauche M, Kim YS, Mulak A, Duboc H, Taché Y. Intracerebroventricular administration of TRH Agonist, RX-77368 alleviates visceral pain induced by colorectal distension in rats. Peptides 2024; 175:171181. [PMID: 38423212 DOI: 10.1016/j.peptides.2024.171181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 01/18/2024] [Accepted: 02/26/2024] [Indexed: 03/02/2024]
Abstract
Thyrotropin-releasing hormone (TRH) acts centrally to exert pleiotropic actions independently from its endocrine function, including antinociceptive effects against somatic pain in rodents. Whether exogenous or endogenous activation of TRH signaling in the brain modulates visceral pain is unknown. Adult male Sprague-Dawley rats received an intracerebroventricular (ICV) injection of the stable TRH analog, RX-77368 (10, 30 and 100 ng/rat) or saline (5 µl) or were semi-restrained and exposed to cold (4°C) for 45 min. The visceromotor response (VMR) to graded phasic colorectal distensions (CRD) was monitored using non-invasive intracolonic pressure manometry. Naloxone (1 mg/kg) was injected subcutaneously 10 min before ICV RX-77368 or saline. Fecal pellet output was monitored for 1 h after ICV injection. RX-77368 ICV (10, 30 and 100 ng/rat) reduced significantly the VMR by 56.7%, 67.1% and 81.1% at 40 mmHg and by 30.3%, 58.9% and 87.4% at 60 mmHg respectively vs ICV saline. Naloxone reduced RX-77368 (30 and 100 ng, ICV) analgesic response by 51% and 28% at 40 mmHg and by 30% and 33% at 60 mmHg respectively, but had no effect per se. The visceral analgesia was mimicked by the acute exposure to cold. At the doses of 30 and 100 ng, ICV RX-77368 induced defecation within 30 min. These data established the antinociceptive action of RX-77368 injected ICV in a model of visceral pain induced by colonic distension through recruitment of both opioid and non-opioid dependent mechanisms.
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Affiliation(s)
- Muriel Larauche
- Digestive Diseases Research Center and G. Oppenheimer Center for Neurobiology of Stress and Resilience, Department of Medicine, Vatche and Tamar Manoukian Division of Digestive Diseases, University of California Los Angeles, and VA Greater Los Angeles Healthcare System, CA 90073, USA.
| | - Yong Sung Kim
- Digestive Diseases Research Center and G. Oppenheimer Center for Neurobiology of Stress and Resilience, Department of Medicine, Vatche and Tamar Manoukian Division of Digestive Diseases, University of California Los Angeles, and VA Greater Los Angeles Healthcare System, CA 90073, USA
| | - Agata Mulak
- Digestive Diseases Research Center and G. Oppenheimer Center for Neurobiology of Stress and Resilience, Department of Medicine, Vatche and Tamar Manoukian Division of Digestive Diseases, University of California Los Angeles, and VA Greater Los Angeles Healthcare System, CA 90073, USA
| | - Henri Duboc
- Digestive Diseases Research Center and G. Oppenheimer Center for Neurobiology of Stress and Resilience, Department of Medicine, Vatche and Tamar Manoukian Division of Digestive Diseases, University of California Los Angeles, and VA Greater Los Angeles Healthcare System, CA 90073, USA
| | - Yvette Taché
- Digestive Diseases Research Center and G. Oppenheimer Center for Neurobiology of Stress and Resilience, Department of Medicine, Vatche and Tamar Manoukian Division of Digestive Diseases, University of California Los Angeles, and VA Greater Los Angeles Healthcare System, CA 90073, USA
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Guo X, Lei C, Liang H, An J, Fang Y, Zhang X, Wang Z, Hu C, Jiang X. Chronic Sacral Nerve Stimulation Inhibits Visceral Hypersensitivity in Diarrhea-Predominant Irritable Bowel Syndrome Rats Model. Neuromodulation 2024; 27:295-301. [PMID: 37930296 DOI: 10.1016/j.neurom.2023.08.010] [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] [Received: 01/29/2023] [Revised: 07/08/2023] [Accepted: 08/08/2023] [Indexed: 11/07/2023]
Abstract
OBJECTIVE Sacral nerve stimulation (SNS) is emerging as a novel treatment for irritable bowel syndrome (IBS). However, its effects are limited, and the underlying mechanisms remain largely unknown. MATERIALS AND METHODS In this study, rats were divided into three groups (n = 12 rats per group): 1) the SNS group; 2) the sham SNS group (the sham group for short); and 3) the control group. The SNS and sham groups were exposed to chronic and acute stress to establish an IBS model. Electrode implantation surgery was performed in rats with the IBS model. The SNS group received electrical stimulation for 30 minutes every day for seven days. Abdominal withdrawal reflex (AWR) was used to evaluate the effect of SNS on visceral sensitivity in diarrhea-predominant IBS (IBS-D) rats. The frequency domain of heart rate variability (HRV) was analyzed to assess the effect of SNS on regulating the autonomic function. The expression of transient receptor potential vanilloid 1 (TRPV1) in the colon, spinal cord, and hippocampus was detected by immunohistochemistry to explore the mechanism of SNS in IBS-D rats. RESULTS Compared with the sham group, AWR scores were significantly decreased under different gas volumes of stimulation of 0.4, 0.6, and 0.8 ml for rectal distention in the SNS group (all p < 0.05). However, there was no significant difference <1.0 ml between the two groups (p > 0.05). Compared with the sham group, the frequency domain indexes of HRV were significantly altered. Normalized low-frequency power and low frequency-to-high frequency ratio were significantly decreased, and normalized high-frequency power was significantly increased in the SNS group (all p < 0.05). Moreover, the expression of TRPV1 in the spinal cord and colon in the SNS group was significantly decreased compared with the sham group (both p < 0.05). These results suggested that chronic SNS not only improved the visceral sensitivity and autonomic dysfunction but also decreased the expression of TRPV1 in the spinal cord-gut tissue in IBS-D rats. CONCLUSION Chronic SNS was found to have an inhibitory effect on visceral hypersensitivity in IBS-D rats, providing experimental evidence for its potential clinical application in IBS.
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Affiliation(s)
- Xiaojuan Guo
- Department of Gastroenterology, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, China
| | - Changsheng Lei
- National Engineering Research Center of Neuromodulation, School of Aerospace Engineering, Tsinghua University, Beijing, China
| | - Hanwei Liang
- Department of Gastroenterology, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, China
| | - Jiaxu An
- Department of Gastroenterology, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, China
| | - Yanbin Fang
- Department of Gastroenterology, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, China
| | - Xiaolu Zhang
- Department of Gastroenterology, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, China
| | - Zhiyan Wang
- CAS Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China; Department of Psychology, University of Chinese Academy of Science, Beijing, China
| | - Chunhua Hu
- National Engineering Research Center of Neuromodulation, School of Aerospace Engineering, Tsinghua University, Beijing, China
| | - Xuan Jiang
- Department of Gastroenterology, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, China.
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Wang X, Chen JDZ. Therapeutic potential and mechanisms of sacral nerve stimulation for gastrointestinal diseases. J Transl Int Med 2023; 11:115-127. [PMID: 37408571 PMCID: PMC10318922 DOI: 10.2478/jtim-2023-0086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/07/2023] Open
Abstract
Background The aim of this systemtic review is to introduce clinical applications (especially emerging) and potential mechanisms of sacral nerve stimulation (SNS) for treating various gastrointestinal diseases. Materials and Methods PubMed and Web of Science were searched for studies published on SNS and its clinical applications in fecal incontinence (limited to systematic review and meta-analysis of clinical studies), constipation (limited to reviews and randomized control clinical studies), irritable bowel syndrome (IBS), inflammatory bowel disease (IBD) and upper gastrointestinal motility disorders. The relevant studies were pooled, and their findings were summarized and discussed. Results SNS is an approved method for treating fecal incontinence. Systematic review and meta-analysis demonstrated high efficacy of the SNS therapy for fecal incontinence. Increased anal sphincter pressure and improvement in rectal sensation were reported as major mechanisms involved in the SNS therapy. SNS has also been proposed for treating constipation, but the therapy has been shown ineffective. There is a lack in SNS methodological optimization and mechanistic research. A few basic and clinical studies have reported the potential of SNS for treating visceral pain in IBS. SNS seemed capable of improving mucosal barrier functions. Several case reports are available in the literature on the treatment of IBD with SNS. Several laboratory studies suggested therapeutic potential of a special method of SNS for IBD. Cholinergic anti-inflammatory mechanisms were reported. Due to a recently reported spinal afferent and vagal efferent pathway of SNS, a few preclinical studies reported the potential of SNS for upper gastrointestinal motility disorders. However, no clinical studies have been performed. Conclusions SNS for fecal incontinence is a well-established clinical therapy. However, the current method of SNS is ineffective for treating constipation. Further methodological development and randomized clinical trials are needed to explore potential applications of SNS for IBS and IBD.
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Affiliation(s)
- Ximeng Wang
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD21228, USA
| | - Jiande DZ Chen
- Department of Internal Medicine, University of Michigan School of Medicine, Ann ArborMI48109, USA
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Opioid-Associated Anorectal Dysfunction in Chronic Constipation. Dig Dis Sci 2022; 67:3904-3910. [PMID: 34699000 DOI: 10.1007/s10620-021-07288-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Accepted: 10/11/2021] [Indexed: 12/09/2022]
Abstract
INTRODUCTION The role of anorectal and defecatory dysfunction in opioid-related constipation is unclear. We aimed to evaluate the relationship between opioid use and rectal sensation, defecatory function, and balloon expulsion on anorectal physiology testing. METHODS This was a retrospective cohort study of consecutive adults undergoing high-resolution anorectal manometry (HRAM) at a tertiary center for constipation. Clinical characteristics, medication use, and HRAM findings were obtained. Statistical analyses were performed using Fisher-exact/student t-test for univariate analyses and logistic/general linear regression for multivariable analyses to compare patients with no opioid use, recent (< 3 months) use, and distant (> 3 months) use. RESULTS 424 patients (49.8 ± 17.2 years; 85.6% female) were included. Compared to those without opioid history, patients with recent use had increased volumes for first rectal sensation (70.4 mL vs 59.4, p = 0.043), urge (120.5 mL vs 101.5, p = 0.017), and maximal tolerance (170.2 mL vs 147.2, p = 0.0018), but not patients with distant use. Recent opioid use was associated with increased risk of dyssynergic defecation (DD) (61.8% vs 46.4%, p = 0.035), but not failed balloon expulsion. On multivariable models controlling for potential confounders, recent opioid use, but not distant use, remained independently correlated with increased volumes for first rectal sensation (β-coefficient 9.78, p = 0.019), urge (β-coefficient 16.7, p = 0.0060), and maximal tolerance (β-coefficient 22.9, p = 0.0032), and higher risk for DD (aOR = 2.18, p = 0.026). CONCLUSION Recent opioid use was an independent risk factor for rectal hyposensitivity and DD on HRAM in patients with constipation, but that effect may decrease with discontinuation of use. Anorectal physiology testing should be considered in patients with opioid-associated constipation.
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Jin X, Gharibani P, Yin J, Chen JDZ. Neuro-Immune Modulation Effects of Sacral Nerve Stimulation for Visceral Hypersensitivity in Rats. Front Neurosci 2021; 15:645393. [PMID: 34276280 PMCID: PMC8282909 DOI: 10.3389/fnins.2021.645393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 06/01/2021] [Indexed: 11/21/2022] Open
Abstract
Background: Visceral hypersensitivity (VH) is one of the underlying pathophysiologies of irritable bowel syndrome. Mast cell overactivation has been found to be one of the main causes of VH. We investigated the effects and mechanisms of actions of sacral nerve stimulation (SNS) on visceral pain in a rodent model of VH. Methods: The VH was established by an intrarectal infusion of AA in 10-day-old pups. Rats were chronically implanted with electrodes for SNS and recording electromyogram (EMG) and electrocardiogram. The acute study was performed in 2-randomized sessions with SNS (14 Hz, 330 μs, 40% motor threshold or MT, 30 min) or sham-SNS. Later on, rats were randomized into SNS/sham-SNS groups and a chronic study was performed with 2 h-daily SNS or sham-SNS for 21 days. Visceromotor reflexes were assessed by abdominal EMG and withdrawal reflex (AWR). Colon tissues were collected to study colonic acetylcholine (ACh), the enteric neurons (ChAT, nNOS, and PGP9.5), mast cells activity [Tryptase, prostaglandins E2 (PGE2), and cyclooxygenases-2 (COX2)] and pain markers [nerve growth factor (NGF) and Sub-P]. Key Results: Sacral nerve stimulation significantly improved visceromotor reflexes assessed by the EMG and AWR, compared with sham-SNS. SNS normalized the protein expressions of ChAT and nNOS and regulated mast cells activity by downregulating Tryptase, COX2, and PGE2. Neonatal AA administration upregulated NGF and Sub-P; chronic SNS significantly decreased these pain biomarkers. Concurrently, chronic SNS increased ACh in colon tissues and vagal efferent activity. Conclusions: Sacral nerve stimulation reduces VH in rats and this ameliorating effect might be attributed to the suppression of mast cell overactivation in the colon tissue via the modulation of autonomic nervous system functions.
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Affiliation(s)
- Xue Jin
- Division of Gastroenterology and Hepatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Payam Gharibani
- Division of Neuroimmunology, Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Jieyun Yin
- Division of Gastroenterology and Hepatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Jiande D Z Chen
- Division of Gastroenterology and Hepatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
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Chen Y, Guo Y, Gharibani P, Chen J, Selaru FM, Chen JDZ. Transitional changes in gastrointestinal transit and rectal sensitivity from active to recovery of inflammation in a rodent model of colitis. Sci Rep 2021; 11:8284. [PMID: 33859347 PMCID: PMC8050040 DOI: 10.1038/s41598-021-87814-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Accepted: 04/05/2021] [Indexed: 11/09/2022] Open
Abstract
Patients with ulcerative colitis are typically suspected of an inflammatory flare based on suggestive symptoms of inflammation. The aim of this study was to evaluate the impact of inflammation on colonic motility and rectal sensitivity from active to recovery of inflammation. Male rats were given drinking water with 5% dextran sulfate sodium for 7 days. Inflammation, intestinal motor and sensory functions were investigated weekly for 6 weeks. (1) The disease activity index score, fecal calprotectin and tumor necrosis factor alpha were increased from Day 0 to Day 7 (active inflammation) and then decreased gradually until recovery. (2) Distal colon transit was accelerated on Day 7, and then remained unchanged. Whole gut transit was delayed on Day 7 but accelerated from Day 14 to Day 42. (3) Rectal compliance was unaffected from Day 0 to Day 7, but decreased afterwards. (4) Rectal hypersensitivity was noted on Day 7 and persistent. (5) Plasma acetylcholine was decreased on Day 7 but increased from Day 14 to Day 42. Nerve growth factor was increased from Day 7 to Day 42. DSS-induced inflammation leads to visceral hypersensitivity that is sustained until the resolution of inflammation, probably mediated by NGF. Rectal compliance is reduced one week after the DSS-induced inflammation and the reduction is sustained until the resolution of inflammation. Gastrointestinal transit is also altered during and after active colonic inflammation.
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Affiliation(s)
- Yan Chen
- Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Division of Gastroenterology, Binzhou Medical University Hospital, Binzhou, Shandong, China
| | - Yu Guo
- Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Payam Gharibani
- Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jie Chen
- Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Florin M Selaru
- Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jiande D Z Chen
- Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA. .,Division of Gastroenterology and Hepatology, University of Michigan, Ann Arbor, MI, USA.
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Jiang L, Zhang S, Zhang N, Chen JDZ. Optimized Tibial Nerve Stimulation Partially Reduces Visceral Hypersensitivity in Rats Mediated via Autonomic and Opioid Mechanisms. Neuromodulation 2021; 24:1003-1011. [PMID: 33615647 DOI: 10.1111/ner.13378] [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: 07/20/2020] [Revised: 01/24/2021] [Accepted: 02/04/2021] [Indexed: 11/28/2022]
Abstract
OBJECTIVES The aim of this study was to investigate the therapeutic effect and possible mechanisms of tibial nerve stimulation (TNS) on visceral hypersensitivity in rats. MATERIALS AND METHODS 1) The effects of TNS with five sets of parameters on visceral sensitivity in normal rats were evaluated by the assessment of abdominal electromyogram (EMG) and abdominal withdrawal reflex (AWR). 2) The effects and mechanisms of TNS with a special set of parameters (14 Hz, 330 μsec, and 40% motor threshold) were evaluated in acute visceral hypersensitivity rats induced by restraint stress and colonic hypersensitized rats induced by acetic acid during the neonatal stage assessed by the EMG, AWR, and the spectral analysis of heart rate variability derived from the electrocardiogram. RESULTS 1) In normal rats, TNS did not show any effect on the visceromotor reflex. 2) In rats with restraint stress-induced hypersensitivity, TNS with the special set of parameters reduced AWR scores and EMG responses to rectal distention at a pressure of 20-60 mmHg (p < 0.05, vs. baseline for both AWR and EMG). Concurrently, TNS increased vagal activity and decreased sympathetic activity (p < 0.03 for both). 3) Similar effects were noted on the EMG (p < 0.05, vs. baseline) and AWR (p < 0.05 vs. baseline) with acute and chronic TNS in rats with chronic colonic hypersensitivity and the effects were blocked by naloxone. CONCLUSIONS TNS with parameters of 14 Hz, 330 μsec, and 40% motor threshold is effective in improving visceral hypersensitivity in rodent models of colonic hypersensitivity via the modulation of autonomic and opioid mechanisms.
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Affiliation(s)
- Liuqin Jiang
- Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Gastroenterology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, 210029, China
| | - Shengai Zhang
- Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Nina Zhang
- Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jiande D Z Chen
- Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Division of Gastroenterology and Hepatology, University of Michigan School of Medicine, Ann Arbor, MI, USA
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Chen Y, Cheng J, Zhang Y, Chen JDZ, Seralu FM. Electroacupuncture at ST36 Relieves Visceral Hypersensitivity via the NGF/TrkA/TRPV1 Peripheral Afferent Pathway in a Rodent Model of Post-Inflammation Rectal Hypersensitivity. J Inflamm Res 2021; 14:325-339. [PMID: 33584100 PMCID: PMC7875081 DOI: 10.2147/jir.s285146] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Accepted: 12/31/2020] [Indexed: 12/25/2022] Open
Abstract
Purpose The aim of the study was to investigate the effects of electroacupuncture (EA) at ST36 on rectal hypersensitivity and compliance in DSS-treated post-inflammation rats. In addition, we explored the involvement of mast cells-triggered NGF/TrkA/TRPV1 peripheral afferent pathway. Methods Rats were provided water with 5% dextran sulphate sodium (DSS) for 7 days. Two weeks after the DSS treatment they were subjected to initial and repetitive EA. Different sets of parameters were compared in the initial test and then EA with the selected parameters were performed for 2 weeks. Rectal compliance was assessed by colorectal distension while visceral sensitivity was evaluated by abdominal withdraw reflexes (AWR) and electromyogram (EMG). Masson's trichrome staining was performed to stain collagen and toluidine blue staining was applied to assess the degranulation of mast cells. Nerve growth factor (NGF), tryptase, TrkA and TRPV1 were measured by Western blot or immunofluorescence staining. Results EA at 100 Hz was more effective in improving rectal compliance and visceral hypersensitivity. Daily EA improved visceral hypersensitivity but not rectal compliance. Five weeks after DSS treatment, fibrosis was noted in both sham-EA and EA groups. The expression and activation of mast cells were significantly reduced after the 2-week EA treatment with a concurrent decrease in the expression of colonic NGF/TrkA and TRPV1 in both colon and dorsal root ganglions. Conclusion EA at ST36 with a special set of parameters has no effect on reduced rectal compliance but relieves visceral hypersensitivity via the mast cells-triggered NGF/TrkA/TRPV1 peripheral afferent pathway in DSS-treated post-inflammation rats.
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Affiliation(s)
- Yan Chen
- Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Division of Gastroenterology, Binzhou Medical University Hospital, Binzhou, Shandong, People's Republic of China
| | - Jiafei Cheng
- Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yiling Zhang
- Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jiande D Z Chen
- Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Division of Gastroenterology and Hepatology, University of Michigan, Ann Arbor, MI, USA
| | - Florin M Seralu
- Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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