1
|
Du P, Joshi V, Beyder A. Tracking Gut Motility in Organ and Cultures. Methods Mol Biol 2023; 2644:449-466. [PMID: 37142940 DOI: 10.1007/978-1-0716-3052-5_29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Gastrointestinal (GI) motility is a key component of digestive health, and it is complex, involving a multitude of cell types and mechanisms to drive both rhythmic and arrhythmic activity. Tracking GI motility in organ and tissue cultures across multiple temporal (seconds, minutes, hours, days) scales can provide valuable information regarding dysmotility and to evaluate treatment options. Here, the chapter describes a simple method to monitor GI motility in organotypic cultures, using a single video camera is placed perpendicularly to the surface of the tissue. A cross-correlational analysis is used to track the relative movements of tissues between subsequent frames and subsequent fitting procedures to fit finite element functions to the deformed tissue to calculate the strain fields. Additional motility index measures from the displacement information are used to further quantify the behaviors of the tissues that are maintained in organotypic culture over days. The protocols presented in this chapter can be adapted to study organotypic cultures from other organs.
Collapse
Affiliation(s)
- Peng Du
- Auckland Bioengineering Institute, Department of Engineering Science and Biomedical Engineering, University of Auckland, Auckland, New Zealand.
| | - Vikram Joshi
- Department of Physiology and Biomedical Engineering, Enteric NeuroScience Program (ENSP), Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Arthur Beyder
- Department of Physiology and Biomedical Engineering, Enteric NeuroScience Program (ENSP), Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, MN, USA
| |
Collapse
|
2
|
Kuruppu S, Cheng LK, Avci R, Angeli-Gordon TR, Paskaranandavadivel N. Relationship Between Intestinal Slow-waves, Spike-bursts, and Motility, as Defined Through High-resolution Electrical and Video Mapping. J Neurogastroenterol Motil 2022; 28:664-677. [PMID: 36250373 PMCID: PMC9577564 DOI: 10.5056/jnm21183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 12/01/2022] [Accepted: 12/17/2022] [Indexed: 11/20/2022] Open
Abstract
Background/Aims High-resolution extracellular mapping has improved our understanding of bioelectric slow-wave and spike-burst activity in the small intestine. The spatiotemporal correlation of electrophysiology and motility patterns is of critical interest to intestinal function but remains incompletely defined. Methods Intestinal jejunum segments from in vivo pigs and rabbits were exteriorized, and simultaneous high-resolution extracellular recordings and video recordings were performed. Contractions were quantified with strain fields, and the frequencies and velocities of motility patterns were calculated. The amplitudes, frequencies, and velocities of slow-wave propagation patterns and spike-bursts were quantified and visualized. In addition, the duration, size and energy of spike-burst patches were quantified. Results Slow-wave associated spike-bursts activated periodically at 10.8 ± 4.0 cycles per minute (cpm) in pigs and 10.2 ± 3.2 cpm in rabbits, while independent spike-bursts activated at a frequency of 3.2 ± 1.8 cpm. Independent spike-bursts had higher amplitude and longer duration than slow-wave associated spike-bursts (1.4 ± 0.8 mV vs 0.1 ± 0.1 mV, P < 0.001; 1.8 ± 1.4 seconds vs 0.8 ± 0.3 seconds, P < 0.001 in pigs). Spike-bursts that activated as longitudinal or circumferential patches were associated with contractions in the respective directions. Spontaneous peristaltic contractions were elicited by independent spike-bursts and travelled slower than slow-wave velocity (3.7 ± 0.5 mm/sec vs 10.1 ± 4.7 mm/sec, P = 0.007). Cyclic peristaltic contractions were driven by slow-wave associated spike-bursts and were coupled to slow-wave velocity and frequency in rabbit (14.2 ± 2.3 mm/sec vs 11.5 ± 4.6 mm/sec, P = 0.162; 11.0 ± 0.6 cpm vs 10.8 ± 0.6 cpm, P = 0.970). Conclusions Motility patterns were dictated by patterns of spike-burst patches. When spike-bursts were coupled to slow-waves, periodic motility patterns were observed, while when spike-bursts were not coupled to slow-waves, spontaneous aperiodic motility patterns were captured.
Collapse
Affiliation(s)
- Sachira Kuruppu
- Auckland Bioengineering Institute, University of Auckland, New Zealand
| | - Leo K Cheng
- Auckland Bioengineering Institute, University of Auckland, New Zealand
- Riddet Institute, Center of Research Excellence, New Zealand
- Department of Surgery, Vanderbilt University, Nashville, USA
| | - Recep Avci
- Auckland Bioengineering Institute, University of Auckland, New Zealand
| | | | | |
Collapse
|
3
|
Codutti A, Cremer J, Alim K. Changing Flows Balance Nutrient Absorption and Bacterial Growth along the Gut. PHYSICAL REVIEW LETTERS 2022; 129:138101. [PMID: 36206418 DOI: 10.1103/physrevlett.129.138101] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 08/24/2022] [Indexed: 06/16/2023]
Abstract
Small intestine motility and its ensuing flow of luminal content impact both nutrient absorption and bacterial growth. To explore this interdependence we introduce a biophysical description of intestinal flow and absorption. Rooted in observations of mice we identify the average flow velocity as the key control of absorption efficiency and bacterial growth, independent of the exact contraction pattern. We uncover self-regulation of contraction and flow in response to nutrients and bacterial levels to promote efficient absorption while restraining detrimental bacterial overgrowth.
Collapse
Affiliation(s)
- Agnese Codutti
- Max Planck Institute for Dynamics and Self-Organization, 37077 Göttingen, Germany
| | - Jonas Cremer
- Biology Department, Stanford University, Stanford, 94305 California, USA
| | - Karen Alim
- Max Planck Institute for Dynamics and Self-Organization, 37077 Göttingen, Germany
- Physics Department and CPA, Technische Universität München, 85748 Garching, Germany
| |
Collapse
|
4
|
Waclawiková B, Codutti A, Alim K, El Aidy S. Gut microbiota-motility interregulation: insights from in vivo, ex vivo and in silico studies. Gut Microbes 2022; 14:1997296. [PMID: 34978524 PMCID: PMC8741295 DOI: 10.1080/19490976.2021.1997296] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 09/30/2021] [Accepted: 10/19/2021] [Indexed: 02/06/2023] Open
Abstract
The human gastrointestinal tract is home to trillions of microbes. Gut microbial communities have a significant regulatory role in the intestinal physiology, such as gut motility. Microbial effect on gut motility is often evoked by bioactive molecules from various sources, including microbial break down of carbohydrates, fibers or proteins. In turn, gut motility regulates the colonization within the microbial ecosystem. However, the underlying mechanisms of such regulation remain obscure. Deciphering the inter-regulatory mechanisms of the microbiota and bowel function is crucial for the prevention and treatment of gut dysmotility, a comorbidity associated with many diseases. In this review, we present an overview of the current knowledge on the impact of gut microbiota and its products on bowel motility. We discuss the currently available techniques employed to assess the changes in the intestinal motility. Further, we highlight the open challenges, and incorporate biophysical elements of microbes-motility interplay, in an attempt to lay the foundation for describing long-term impacts of microbial metabolite-induced changes in gut motility.
Collapse
Affiliation(s)
- Barbora Waclawiková
- Host-Microbe Interactions, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Groningen, The Netherlands
| | - Agnese Codutti
- Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany
| | - Karen Alim
- Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany
- Physics Department and Center for Protein Assemblies (CPA), Technische Universität München, Garching, Germany
| | - Sahar El Aidy
- Host-Microbe Interactions, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Groningen, The Netherlands
| |
Collapse
|
5
|
Costa M, Wiklendt L, Hibberd T, Dinning P, Spencer NJ, Brookes S. Analysis of Intestinal Movements with Spatiotemporal Maps: Beyond Anatomy and Physiology. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1383:271-294. [PMID: 36587166 DOI: 10.1007/978-3-031-05843-1_26] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Over 150 years ago, methods for quantitative analysis of gastrointestinal motor patterns first appeared. Graphic representations of physiological variables were recorded with the kymograph after the mid-1800s. Changes in force or length of intestinal muscles could be quantified, however most recordings were limited to a single point along the digestive tract.In parallel, photography and cinematography with X-Rays visualised changes in intestinal shape, but were hard to quantify. More recently, the ability to record physiological events at many sites along the gut in combination with computer processing allowed construction of spatiotemporal maps. These included diameter maps (DMaps), constructed from video recordings of intestinal movements and pressure maps (PMaps), constructed using data from high-resolution manometry catheters. Combining different kinds of spatiotemporal maps revealed additional details about gut wall status, including compliance, which relates forces to changes in length. Plotting compliance values along the intestine enabled combined DPMaps to be constructed, which can distinguish active contractions and relaxations from passive changes. From combinations of spatiotemporal maps, it is possible to deduce the role of enteric circuits and pacemaker cells in the generation of complex motor patterns. Development and application of spatiotemporal methods to normal and abnormal motor patterns in animals and humans is ongoing, with further technical improvements arising from their combination with impedance manometry, magnetic resonance imaging, electrophysiology, and ultrasonography.
Collapse
Affiliation(s)
- Marcello Costa
- College of Medicine and Public Health, Department of Human Physiology, Flinders University, Bedford Park, SA, Australia.
| | - Luke Wiklendt
- Department of Gastroenterology and Surgery, Flinders Medical Centre, Bedford Park, SA, Australia
| | - Tim Hibberd
- College of Medicine and Public Health, Department of Human Physiology, Flinders University, Bedford Park, SA, Australia
| | - Phil Dinning
- Department of Gastroenterology and Surgery, Flinders Medical Centre, Bedford Park, SA, Australia
| | - Nick J Spencer
- College of Medicine and Public Health, Department of Human Physiology, Flinders University, Bedford Park, SA, Australia
| | - Simon Brookes
- College of Medicine and Public Health, Department of Human Physiology, Flinders University, Bedford Park, SA, Australia
| |
Collapse
|
6
|
A soft tubular model reactor based on the bionics of a small intestine: anti particulate fouling by peristalsis. BRAZILIAN JOURNAL OF CHEMICAL ENGINEERING 2021. [DOI: 10.1007/s43153-021-00196-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
7
|
Abstract
In this paper, effects of stationary contraction on mixing and transport of a non-Newtonian fluid in the small intestine are analyzed theoretically. A semi-analytical method is developed to solve the governing equations of fluids flow in the intestine using lubrication theory. Results indicate that the stationary contraction helps in conferring two functions – (1) shearing of the contents, and (2) bidirectional transport over a short distance. The flow resulting from contraction is symmetric and occurs in both the directions; however, they do not lead to a net flow rate in one direction. The amount of shearing developed during such flows is reflective of their mixing ability. The effort of such peristalsis is largely determined by the flow behavior index; where energy requirements of developing similar shearing forces are higher for dilatants and lower for pseudoplastics. Flow is sensitive to frequency of contraction, luminal occlusion and wavelength of the contraction.
Collapse
Affiliation(s)
- RAVI KANT AVVARI
- Department of Biotechnology and Medical Engineering, NIT Rourkela, Odisha 769008, India
- Department of Electrical & Electronics Engineering, Sasi Institute of Technology and Engineering, Tadepalligudem, West Godavari, Andhra Pradesh 534101, India
| |
Collapse
|
8
|
Abstract
A low-glycaemic diet is crucial for those with diabetes and cardiovascular diseases. Information on the glycaemic index (GI) of different ingredients can help in designing novel food products for such target groups. This is because of the intricate dependency of material source, composition, food structure and processing conditions, among other factors, on the glycaemic responses. Different approaches have been used to predict the GI of foods, and certain discrepancies exist because of factors such as inter-individual variation among human subjects. Besides other aspects, it is important to understand the mechanism of food digestion because an approach to predict GI must essentially mimic the complex processes in the human gastrointestinal tract. The focus of this work is to review the advances in various approaches for predicting the glycaemic responses to foods. This has been carried out by detailing conventional approaches, their merits and limitations, and the need to focus on emerging approaches. Given that no single approach can be generalised to all applications, the review emphasises the scope of deriving insights for improvements in methodologies. Reviewing the conventional and emerging approaches for the determination of GI in foods, this detailed work is intended to serve as a state-of-the-art resource for nutritionists who work on developing low-GI foods.
Collapse
|
9
|
Gama LA, Rocha Machado MP, Beckmann APS, Miranda JRDA, Corá LA, Américo MF. Gastrointestinal motility and morphology in mice: Strain-dependent differences. Neurogastroenterol Motil 2020; 32:e13824. [PMID: 32096330 DOI: 10.1111/nmo.13824] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 01/31/2020] [Accepted: 02/04/2020] [Indexed: 12/15/2022]
Abstract
BACKGROUND BALB/c and C57BL/6 mice are widely used in biomedical research; however, the differences between strains are still underestimated. Our aims were to develop an experimental protocol to evaluate the duodenal contractility and gastrointestinal transit in mice using the Alternating Current Biosusceptometry (ACB) technique and to compare gastrointestinal motor function and morphology between BALB/c and C57BL/6 strains. METHODS Male mice were used in experiments (a) duodenal contractility: animals which had a magnetic marker surgically fixed in the duodenum to determine the frequency and amplitude of contractions and (b) gastrointestinal transit: animals which ingested a magnetically marked chow to calculate the Oro-Anal Transit Time (OATT) and the Fecal Pellet Elimination Rate (FPER). The animals were killed after the experiments for organ collection and morphometric analysis. KEY RESULTS BALB/c and C57BL/6 had two different duodenal frequencies (high and low) with similar amplitudes. After 10 hours of monitoring, BALB/c eliminated around 89% of the ingested marker and C57BL/6 eliminated 33%; OATT and FPER were slower for C57BL/6 compared with BALB/c. The OATT and amplitude of low frequency had a strong positive correlation in C57BL/6. For BALB/c, the gastric muscular layer was thicker compared to that measured for C57BL/6. CONCLUSIONS AND INFERENCES The experimental protocol to evaluate duodenal contractility and fecal magnetic pellets output using the ACB technique in mice was successfully established. BALB/c strains had higher duodenal frequencies and a shorter time to eliminate the ingested marker. Our results showed differences in both motor function and gastrointestinal morphology between BALB/c and C57BL/6 strains.
Collapse
Affiliation(s)
- Loyane Almeida Gama
- Institute of Biosciences, São Paulo State University, UNESP, Botucatu, Brazil
| | | | - Ana Paula Simões Beckmann
- Institute of Biological Sciences and Health, Federal University of Mato Grosso, UFMT, Barra do Garças, Brazil
| | | | | | - Madileine Francely Américo
- Institute of Biosciences, São Paulo State University, UNESP, Botucatu, Brazil.,Institute of Biological Sciences and Health, Federal University of Mato Grosso, UFMT, Barra do Garças, Brazil
| |
Collapse
|
10
|
Du P, Liu JYH, Sukasem A, Qian A, Calder S, Rudd JA. Recent progress in electrophysiology and motility mapping of the gastrointestinal tract using multi-channel devices. J R Soc N Z 2020. [DOI: 10.1080/03036758.2020.1735455] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Peng Du
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
- Department of Engineering Science, The University of Auckland, Auckland, New Zealand
| | - Julia Y. H. Liu
- Faculty of Medicine, School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, People’s Republic of China
| | - Atchariya Sukasem
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Anna Qian
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Stefan Calder
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - John A. Rudd
- Faculty of Medicine, School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, People’s Republic of China
| |
Collapse
|
11
|
Zhang Y, Wu P, Jeantet R, Dupont D, Delaplace G, Chen XD, Xiao J. How motility can enhance mass transfer and absorption in the duodenum: Taking the structure of the villi into account. Chem Eng Sci 2020. [DOI: 10.1016/j.ces.2019.115406] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
12
|
Humenick A, Chen BN, Lauder CIW, Wattchow DA, Zagorodnyuk VP, Dinning PG, Spencer NJ, Costa M, Brookes SJH. Characterization of projections of longitudinal muscle motor neurons in human colon. Neurogastroenterol Motil 2019; 31:e13685. [PMID: 31355986 DOI: 10.1111/nmo.13685] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Revised: 07/07/2019] [Accepted: 07/08/2019] [Indexed: 12/08/2022]
Abstract
BACKGROUND The enteric nervous system contains inhibitory and excitatory motor neurons which modulate smooth muscle contractility. Cell bodies of longitudinal muscle motor neurons have not been identified in human intestine. METHODS We used retrograde tracing ex vivo with DiI, with multiple labeling immunohistochemistry, to characterize motor neurons innervating tenial and inter-tenial longitudinal muscle of human colon. KEY RESULTS The most abundant immunohistochemical markers in the tertiary plexus were vesicular acetylcholine transporter, nitric oxide synthase (NOS), and vasoactive intestinal polypeptide (VIP). Of retrogradely traced motor neurons innervating inter-tenial longitudinal muscle, 95% were located within 6mm oral or anal to the DiI application site. Excitatory motor neuron cell bodies, immunoreactive for choline acetyltransferase (ChAT), were clustered aborally, whereas NOS-immunoreactive cell bodies were distributed either side of the DiI application site. Motor neurons had small cell bodies, averaging 438 + 18µm2 in cross-sectional area, similar for ChAT- and NOS-immunoreactive subtypes. Motor neurons innervating the tenia had slightly longer axial projections, with 95% located within 9mm. ChAT-immunoreactive excitatory motor neurons to tenia were clustered aborally, whereas NOS-immunoreactive inhibitory motor neurons had both ascending and descending projections. VIP immunoreactivity was rarely present without NOS immunoreactivity in motor neurons. CONCLUSIONS AND INFERENCES Tenial and inter-tenial motor neurons innervating the longitudinal muscle have short projections. Inhibitory motor neurons have less polarized projections than cholinergic excitatory motor neurons. Longitudinal and circular muscle layers are innervated by distinct local populations of excitatory and inhibitory motor neurons. A population of human enteric neurons that contribute significantly to colonic motility has been characterized.
Collapse
Affiliation(s)
- Adam Humenick
- Human Physiology, Medical Bioscience, Centre for Neuroscience, College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Bao Nan Chen
- Human Physiology, Medical Bioscience, Centre for Neuroscience, College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Chris I W Lauder
- Department of Surgery, Flinders Medical Centre, Adelaide, SA, Australia
| | - David A Wattchow
- Department of Surgery, Flinders Medical Centre, Adelaide, SA, Australia
| | - Vladimir P Zagorodnyuk
- Human Physiology, Medical Bioscience, Centre for Neuroscience, College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Phil G Dinning
- Department of Surgery, Flinders Medical Centre, Adelaide, SA, Australia
| | - Nick J Spencer
- Human Physiology, Medical Bioscience, Centre for Neuroscience, College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Marcello Costa
- Human Physiology, Medical Bioscience, Centre for Neuroscience, College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Simon J H Brookes
- Human Physiology, Medical Bioscience, Centre for Neuroscience, College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| |
Collapse
|
13
|
Lentle RG. Deconstructing the physical processes of digestion: reductionist approaches may provide greater understanding. Food Funct 2018; 9:4069-4084. [PMID: 30011345 DOI: 10.1039/c8fo00722e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
I provide a broad overview of the physical factors that govern intestinal digestion i.e. the admixture of food particles in digesta with secreted enzymes and the subsequent mass transfer of liberated nutrients from the surfaces of particles to the gut wall, with a view to outlining the quantitative work that is required to determine the relative importance of these factors in the digestion of particular foods. I first discuss what is known of the mechanical forces generated by contraction of the walls of the various segments of the gut and the level of diffusive, and advective mixing that it generates within the lumen. I then discuss the particular physical effects that may limit the digestion of solid, physically and/or chemically homogenous and heterogeneous food particles, notably capillarity, porosity, poro-elastic flow and compaction and their likely effects on diffusive and convective mass transfer at particulate surfaces. Similarly, I discuss mucins and morphology on mass transfer of nutrients to the gut wall i.e. the mucosa.
Collapse
Affiliation(s)
- R G Lentle
- Digestive Biomechanics Group, College of Health, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand.
| |
Collapse
|
14
|
Trujillo-de Santiago G, Lobo-Zegers MJ, Montes-Fonseca SL, Zhang YS, Alvarez MM. Gut-microbiota-on-a-chip: an enabling field for physiological research. ACTA ACUST UNITED AC 2018; 2. [PMID: 33954286 DOI: 10.21037/mps.2018.09.01] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Overwhelming scientific evidence today confirms that the gut microbiota is a central player in human health. Knowledge about interactions between human gut microbiota and human health has evolved rapidly in the last decade, based on experimental work involving analysis of human fecal samples or animal models (mainly rodents). A more detailed and cost-effective description of this interplay is now being enabled by the use of in vitro systems (i.e., gut-microbiota-on-chip systems) that recapitulate key aspects of the interaction between microbiota and human cells. Here, we review recent examples of the design and use of pioneering on-chip platforms for the study of the cross-talk between representative members of human microbiota and human microtissues. In these systems, the combined use of state-of-the-art microfluidics, biomaterials, cell culture techniques, classical microbiology, and a touch of genetic expression profiling have converged for the development of gut-on-chip platforms capable of recreating key features of the interplay between human microbiota and host human tissues. We foresee that the integration of novel microfabrication techniques and stem cell technologies will further accelerate the development of more complex and physiologically relevant microbiota-on-chip platforms. In turn, this will foster the faster acquisition of knowledge regarding human microbiota and will enable important advances in the understanding of how to control or prevent disease.
Collapse
Affiliation(s)
- Grissel Trujillo-de Santiago
- Centro de Biotecnología-FEMSA, Tecnológico de Monterrey.,Departamento de Mecatrónica e Ingeniería Eléctrica, Campus Monterrey, CP 64849, Monterrey, Nuevo León, México
| | - Matías José Lobo-Zegers
- Centro de Biotecnología-FEMSA, Tecnológico de Monterrey.,Departamento de Mecatrónica e Ingeniería Eléctrica, Campus Monterrey, CP 64849, Monterrey, Nuevo León, México
| | - Silvia Lorena Montes-Fonseca
- Departamento de Bioingeniería, Escuela de Ingeniería y Ciencias, Tecnológico de Monterrey, CP 31300, Chihuahua, México
| | - Yu Shrike Zhang
- Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA, USA
| | | |
Collapse
|
15
|
Lentle RG, Hulls CM. Quantifying Patterns of Smooth Muscle Motility in the Gut and Other Organs With New Techniques of Video Spatiotemporal Mapping. Front Physiol 2018; 9:338. [PMID: 29686624 PMCID: PMC5900429 DOI: 10.3389/fphys.2018.00338] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 03/20/2018] [Indexed: 01/12/2023] Open
Abstract
The uses and limitations of the various techniques of video spatiotemporal mapping based on change in diameter (D-type ST maps), change in longitudinal strain rate (L-type ST maps), change in area strain rate (A-type ST maps), and change in luminous intensity of reflected light (I-maps) are described, along with their use in quantifying motility of the wall of hollow structures of smooth muscle such as the gut. Hence ST-methods for determining the size, speed of propagation and frequency of contraction in the wall of gut compartments of differing geometric configurations are discussed. We also discuss the shortcomings and problems that are inherent in the various methods and the use of techniques to avoid or minimize them. This discussion includes, the inability of D-type ST maps to indicate the site of a contraction that does not reduce the diameter of a gut segment, the manipulation of axis [the line of interest (LOI)] of L-maps to determine the true axis of propagation of a contraction, problems with anterior curvature of gut segments and the use of adjunct image analysis techniques that enhance particular features of the maps.
Collapse
Affiliation(s)
- Roger G Lentle
- Physiology Department, Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand
| | - Corrin M Hulls
- Physiology Department, Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand
| |
Collapse
|
16
|
Wei R, Parsons SP, Huizinga JD. Network properties of interstitial cells of Cajal affect intestinal pacemaker activity and motor patterns, according to a mathematical model of weakly coupled oscillators. Exp Physiol 2017; 102:329-346. [DOI: 10.1113/ep086077] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Accepted: 12/15/2016] [Indexed: 12/13/2022]
Affiliation(s)
- Ruihan Wei
- McMaster University, Department of Medicine; Farncombe Family Digestive Health Research Institute; Hamilton ON Canada
| | - Sean P. Parsons
- McMaster University, Department of Medicine; Farncombe Family Digestive Health Research Institute; Hamilton ON Canada
| | - Jan D. Huizinga
- McMaster University, Department of Medicine; Farncombe Family Digestive Health Research Institute; Hamilton ON Canada
| |
Collapse
|
17
|
Brüssow H. How stable is the human gut microbiota? And why this question matters. Environ Microbiol 2016; 18:2779-83. [PMID: 27459371 DOI: 10.1111/1462-2920.13473] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Accepted: 07/24/2015] [Indexed: 12/29/2022]
Affiliation(s)
- Harald Brüssow
- Nestlé Research Center, Nutrition and Health Research, Host-Microbe Interaction, CH-1000 Lausanne 26, Switzerland.
| |
Collapse
|
18
|
Lim YF, de Loubens C, Love RJ, Lentle RG, Janssen PWM. Flow and mixing by small intestine villi. Food Funct 2016; 6:1787-95. [PMID: 25968481 DOI: 10.1039/c5fo00285k] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Flow and mixing in the small intestine are multi-scale processes. Flows at the scale of the villi (finger-like structures of ≈500 μm length) are poorly understood. We developed a three-dimensional lattice-Boltzmann model to gain insight into the effects of villous movements and the rheology of digesta on flow, mixing and absorption of nutrients at the periphery of the intestinal lumen. Our model simulated the hydrodynamic consequences of villi movements that resulted from folding of the mucosa during longitudinal contractions. We found that cyclic approximation and separation of groups of villi generated laminar eddies at the edges of the group and augmented mass transfers in the radial direction between the inter-villous space and the intestinal lumen which improved the absorption of nutrients and mixing at the periphery of the lumen. This augmentation was greater with highly diffusible nutrients and with high levels of shear-thinning (pseudoplasticity) of the fluid. We compared our results with bulk flows simulations done by previous workers and concluded that villous movements during longitudinal contractions is a major radial mixing mechanism in the small intestine and increases mixing and absorption around the mucosa despite adverse rheology.
Collapse
Affiliation(s)
- Y F Lim
- Institute of Food, Nutrition and Human Health, Massey University, Private Bag 11222, Palmerston North, New Zealand.
| | | | | | | | | |
Collapse
|
19
|
Kendig DM, Hurst NR, Grider JR. Spatiotemporal Mapping of Motility in Ex Vivo Preparations of the Intestines. J Vis Exp 2016:e53263. [PMID: 26863156 PMCID: PMC4781693 DOI: 10.3791/53263] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Multiple approaches have been used to record and evaluate gastrointestinal motility including: recording changes in muscle tension, intraluminal pressure, and membrane potential. All of these approaches depend on measurement of activity at one or multiple locations along the gut simultaneously which are then interpreted to provide a sense of overall motility patterns. Recently, the development of video recording and spatiotemporal mapping (STmap) techniques have made it possible to observe and analyze complex patterns in ex vivo whole segments of colon and intestine. Once recorded and digitized, video records can be converted to STmaps in which the luminal diameter is converted to grayscale or color [called diameter maps (Dmaps)]. STmaps can provide data on motility direction (i.e., stationary, peristaltic, antiperistaltic), velocity, duration, frequency and strength of contractile motility patterns. Advantages of this approach include: analysis of interaction or simultaneous development of different motility patterns in different regions of the same segment, visualization of motility pattern changes over time, and analysis of how activity in one region influences activity in another region. Video recordings can be replayed with different timescales and analysis parameters so that separate STmaps and motility patterns can be analyzed in more detail. This protocol specifically details the effects of intraluminal fluid distension and intraluminal stimuli that affect motility generation. The use of luminal receptor agonists and antagonists provides mechanistic information on how specific patterns are initiated and how one pattern can be converted into another pattern. The technique is limited by the ability to only measure motility that causes changes in luminal diameter, without providing data on intraluminal pressure changes or muscle tension, and by the generation of artifacts based upon experimental setup; although, analysis methods can account for these issues. When compared to previous techniques the video recording and STmap approach provides a more comprehensive understanding of gastrointestinal motility.
Collapse
Affiliation(s)
- Derek M Kendig
- Department of Physiology and Biophysics, Virginia Commonwealth University; Department of Biology, Loyola University Maryland;
| | - Norm R Hurst
- Department of Physiology and Biophysics, Virginia Commonwealth University
| | - John R Grider
- Department of Physiology and Biophysics, Virginia Commonwealth University
| |
Collapse
|
20
|
Du P, Paskaranandavadivel N, Angeli TR, Cheng LK, O'Grady G. The virtual intestine: in silico modeling of small intestinal electrophysiology and motility and the applications. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2015; 8:69-85. [PMID: 26562482 DOI: 10.1002/wsbm.1324] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 10/01/2015] [Accepted: 10/02/2015] [Indexed: 02/06/2023]
Abstract
The intestine comprises a long hollow muscular tube organized in anatomically and functionally discrete compartments, which digest and absorb nutrients and water from ingested food. The intestine also plays key roles in the elimination of waste and protection from infection. Critical to all of these functions is the intricate, highly coordinated motion of the intestinal tract, known as motility, which is coregulated by hormonal, neural, electrophysiological and other factors. The Virtual Intestine encapsulates a series of mathematical models of intestinal function in health and disease, with a current focus on motility, and particularly electrophysiology. The Virtual Intestine is being cohesively established across multiple physiological scales, from sub/cellular functions to whole organ levels, facilitating quantitative evaluations that present an integrative in silico framework. The models are also now finding broad physiological applications, including in evaluating hypotheses of slow wave pacemaker mechanisms, smooth muscle electrophysiology, structure-function relationships, and electromechanical coupling. Clinical applications are also beginning to follow, including in the pathophysiology of motility disorders, diagnosing intestinal ischemia, and visualizing colonic dysfunction. These advances illustrate the emerging potential of the Virtual Intestine to effectively address multiscale research challenges in interdisciplinary gastrointestinal sciences.
Collapse
Affiliation(s)
- Peng Du
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | | | - Timothy R Angeli
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Leo K Cheng
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Gregory O'Grady
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| |
Collapse
|
21
|
Fullard LA, Lammers WJ, Ferrua MJ. Advective mixing due to longitudinal and segmental contractions in the ileum of the rabbit. J FOOD ENG 2015. [DOI: 10.1016/j.jfoodeng.2015.03.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
|
22
|
Effects of Amoxicillin and Clavulanic Acid on the Spontaneous Mechanical Activity of Juvenile Rat Duodenum. J Pediatr Gastroenterol Nutr 2015; 61:340-5. [PMID: 25844706 DOI: 10.1097/mpg.0000000000000804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
OBJECTIVES There are a limited number of medications for the treatment of foregut dysmotility. Enteral amoxicillin/clavulanic acid induces phase III duodenal contractions in a fasting pediatric patient. The mechanism by which this occurs is unknown. We examined the individual contributions of amoxicillin and clavulanic acid on the spontaneous mechanical activity of juvenile rat duodenum to better understand this phenomenon. METHODS Duodenal segments from juvenile rats were longitudinally attached to force transducers in organ baths. Samples were cumulatively exposed to amoxicillin or clavulanic acid. Separate samples were exposed to carbachol alone to assess response in both the presence and absence of amoxicillin or clavulanic acid. Basal tone, frequency, and amplitude of contractions were digitized and recorded. RESULTS The amplitude of the spontaneous contractions increased with amoxicillin. Inhibition of neuronal activity prevented this effect. Clavulanic acid did not affect the spontaneous contractions. Basal tone and the rate of contractions did not differ with either drug. Stimulation with carbachol in the presence of amoxicillin caused a statistically significant increase in the contractility compared with carbachol alone. CONCLUSIONS Amoxicillin alters the spontaneous longitudinal mechanical activity of juvenile rat duodenum. Our results suggest that amoxicillin modulates the spontaneous pattern of cyclic mechanical activity of duodenal smooth muscle through noncholinergic, neurally mediated mechanisms. Our work provides an initial physiologic basis for the therapeutic use of amoxicillin in patients with gastrointestinal dysmotility.
Collapse
|
23
|
|
24
|
A review of mixing and propulsion of chyme in the small intestine: fresh insights from new methods. J Comp Physiol B 2015; 185:369-87. [PMID: 25648621 DOI: 10.1007/s00360-015-0889-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 01/05/2015] [Accepted: 01/17/2015] [Indexed: 01/18/2023]
Abstract
The small intestine is a convoluted flexible tube of inconstant form and capacity through which chyme is propelled and mixed by varying patterns of contraction. These inconstancies have prevented quantitative comparisons of the manner in which contractile activity engenders mixing of contained chyme. Recent quantitative work based on spatiotemporal mapping of intestinal contractions, macro- and micro-rheology, particle image velocimetry and real-time modelling has provided new insights into this process. Evidence indicates that the speeds and patterns of the various types of small intestinal contraction are insufficient to secure optimal mixing and enzymatic digestion over a minimal length of intestine. Hence particulate substrates and soluble nutrients become dispersed along the length of the lumen. Mixing within the lumen is not turbulent but results from localised folding and kneading of the contents by contractions but is augmented by the inconstant spatial disposition of the contractions and their component contractile processes. The latter include inconstancies in the sites of commencement and the directions of propagation of contraction in component groups of smooth muscle cells and in the coordination of the radial and circular components of smooth muscle contraction. Evidence suggests there is ongoing augmentation of mixing at the periphery of the lumen, during both the post-prandial and inter-meal periods, to promote flow around and between adjacent villi. This results largely from folding of the relatively inelastic mucosa during repeated radial and longitudinal muscular contraction, causing chyme to be displaced by periodic crowding and separation of the tips of the relatively rigid villi. Further, micro-rheological studies indicate that such peripheral mixing may extend to the apices of enterocytes owing to discontinuities in the mobile mucus layer that covers the ileal mucosa.
Collapse
|
25
|
Role of the enteric nervous system in the elongated sigmoid colon of patients with sigmoid volvulus. Int Surg 2014; 99:699-704. [PMID: 25437573 DOI: 10.9738/intsurg-d-13-00198.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
To clarify the physiologic function of the enteric nervous system (ENS) in the elongated sigmoid colon (ESC) of patients with sigmoid volvulus (SV), we examined the enteric nerve responses in lesional and normal longitudinal muscle strips (LMS) derived from patients with ESC and patients who underwent colon resection for colonic cancers. Thirty preparations of LMS were taken from the lesional sigmoid colons of 10 ESC patients with SV (8 men and 2 women, aged 53 to 80 years, mean 66.2 years). Forty preparations of LMS were taken from the normal sigmoid colons (NSC) of 20 patients with colonic cancer (12 men and 8 women, aged 55 to 76 years, mean 62.3 years). A mechanographic technique was used to evaluate in vitro muscle responses to electrical field stimulation (EFS) before and after treatment with various autonomic nerve blockers. Response to EFS before blockade of the adrenergic and cholinergic nerves was as follows: NSC and ESC significantly demonstrated relaxation reaction rather than contraction reaction (P = 0.0253, P < 0.0001, respectively). ESC showed relaxation reaction more than NSC (P = 0.1138). Response to EFS after blockade of the adrenergic and cholinergic nerves was as follows: NSC and ESC significantly demonstrated relaxation reaction via nonadrenergic noncholinergic (NANC) inhibitory nerves rather than contraction reaction via NANC excitatory nerves (P < 0.0001, P < 0.0001, respectively). ESC with SV significantly showed relaxation reaction more than NSC (P = 0.0092). An increased response of relaxation mediated NANC inhibitory nerves may play a role in impaired motility in the ESC of patients with SV.
Collapse
|
26
|
Janssen PWM, Lentle RG, Chambers P, Reynolds GW, De Loubens C, Hulls CM. Spatiotemporal organization of standing postprandial contractions in the distal ileum of the anesthetized pig. Neurogastroenterol Motil 2014; 26:1651-62. [PMID: 25251369 DOI: 10.1111/nmo.12447] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 08/30/2014] [Indexed: 02/08/2023]
Abstract
BACKGROUND Spatiotemporal (ST) mapping has mainly been applied to ex vivo preparations of the gut. We report the results of ST mapping of the spontaneous and remifentanil-induced motility of circular and longitudinal muscles of the distal ileum in the postprandial anaesthetized pig. METHODS Spatiotemporal maps of strain rate were derived from image sequences of an exteriorized loop of ileum on a superfusion tray at laparotomy. Parameters were obtained by direct measurement from these maps, and by auto- and cross-correlation of map segments. KEY RESULTS Localized domains of standing longitudinal and circular activity that alternated between neighboring domains occurred spontaneously and both were promptly extinguished following intraluminal dosage with lidocaine. Longitudinal or circular contractions within a domain typically occurred at times that would coincide with every second or third cycle of the slow wave but propagated within the domain at a rate consistent with that reported within spike patches. Shortly after intravenous administration of remifentanil, longitudinal and circular contractions at the reported slow wave frequency propagated over longer distances at a high speed before slowing to a rate similar to that reported for slow waves. CONCLUSIONS & INFERENCES ST mapping based on cross-correlation is a robust tool for the analysis of intestinal movement and minimizing movement artefacts. We propose that the ST pattern of standing longitudinal and circular contractions arises from variation in the refractory period of smooth muscle, and hence, in its response to successive slow waves with neural stimuli influencing the former and having a mainly permissive role.
Collapse
Affiliation(s)
- P W M Janssen
- Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand
| | | | | | | | | | | |
Collapse
|
27
|
Tomita R. Are there any functional differences of the enteric nervous system between the right-sided diverticular colon and the left-sided diverticular colon? An in vitro study. Int J Colorectal Dis 2014; 29:571-7. [PMID: 24562545 DOI: 10.1007/s00384-014-1837-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/31/2014] [Indexed: 02/04/2023]
Abstract
PURPOSE To evaluate functional differences of the enteric nervous system (ENS) in patients between right-side colonic diverticula (RCD) and left-sided colonic diverticula (LCD), the author compared the ENS responses between RCD and LCD. METHODS Ten specimens were obtained from 10 patients with RCD, and 16 specimens were taken from 16 LCD. As a control, twenty-two specimens of right-sided normal colon (RNC) were obtained from 22 colonic cancers. Twenty-four specimens of left sided normal colon (LNC) were obtained from 24 colonic cancers. A mechanography was used to evaluate in vitro muscle responses to electrical field stimulation (EFS) before and after treatment with various autonomic nerve blockers. RESULTS Before blockade of the adrenergic and cholinergic nerves, the incidences of contraction via cholinergic nerve in the colons with diverticula were significantly greater than those in the normal colons (right-sided colon; p = 0.0022, left-sided colon; p < 0.0001). There were no significant differences between RNC and LNC (p = 0.3606), and between RCD and LCD (p = 0.7684). After the blockade of adrenergic and cholinergic nerves, the incidence of relaxation via non-adrenergic non-cholinergic inhibitory (NANC) nerve in the normal colons was significantly greater than that in the diverticular colons (right-sided colon; p = 0.0435, left-sided colon; p = 0.0034). There were no significant differences between RNC and LNC (p = 0.2909) and between RCD and LCD (p = 0.9464). CONCLUSION Cholinergic nerves were dominant in bilateral diverticular colon compared with bilateral normal colon. NANC inhibitory nerves were dominant in bilateral normal colon compared with bilateral diverticular colon. There were also no functional differences of the ENS between RCD and LCD.
Collapse
Affiliation(s)
- Ryouichi Tomita
- Department of Surgery, School of Life Dentistry, Nippon Dental University, 2-3-16 Fujimi, Chiyoda-ku, Tokyo, 102-8158, Japan,
| |
Collapse
|
28
|
Characterisation of mixing in the proximal duodenum of the rat during longitudinal contractions and comparison with a fluid mechanical model based on spatiotemporal motility data. PLoS One 2014; 9:e95000. [PMID: 24747714 PMCID: PMC3991651 DOI: 10.1371/journal.pone.0095000] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 03/21/2014] [Indexed: 11/28/2022] Open
Abstract
The understanding of mixing and mass transfers of nutrients and drugs in the small intestine is of prime importance in creating formulations that manipulate absorption and digestibility. We characterised mixing using a dye tracer methodology during spontaneous longitudinal contractions, i.e. pendular activity, in 10 cm segments of living proximal duodenum of the rat maintained ex-vivo. The residence time distribution (RTD) of the tracer was equivalent to that generated by a small number (8) of continuous stirred tank reactors in series. Fluid mechanical modelling, that was based on real sequences of longitudinal contractions, predicted that dispersion should occur mainly in the periphery of the lumen. Comparison with the experimental RTD showed that centriluminal dispersion was accurately simulated whilst peripheral dispersion was underestimated. The results therefore highlighted the potential importance of micro-phenomena such as microfolding of the intestinal mucosa in peripheral mixing. We conclude that macro-scale modeling of intestinal flow is useful in simulating centriluminal mixing, whereas multi-scales strategies must be developed to accurately model mixing and mass transfers at the periphery of the lumen.
Collapse
|
29
|
Fullard L, Lammers W, Wake GC, Ferrua MJ. Propagating longitudinal contractions in the ileum of the rabbit – Efficiency of advective mixing. Food Funct 2014; 5:2731-42. [DOI: 10.1039/c4fo00487f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The flow and mixing of viscous fluids in the small intestine for various types of longitudinal motility.
Collapse
Affiliation(s)
- Luke Fullard
- Institute of Fundamental Sciences
- Massey University
- Palmerston North, New Zealand
| | - Willem Lammers
- Department of Physiology
- College of Medicine and Health Sciences
- United Arab Emirates University
- United Arab Emirates
| | - Graeme C. Wake
- Institute of Natural and Mathematical Sciences
- Massey University
- Auckland, New Zealand
| | - Maria J. Ferrua
- The Riddet Institute
- Massey University
- Palmerston North, New Zealand
| |
Collapse
|
30
|
Lentle RG, Reynolds GW, Janssen PWM. Gastrointestinal tone; its genesis and contribution to the physical processes of digestion. Neurogastroenterol Motil 2013; 25:931-42. [PMID: 24028606 DOI: 10.1111/nmo.12223] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 08/08/2013] [Indexed: 12/24/2022]
Abstract
BACKGROUND Myogenic tone has long been recognised as an important component of gastrointestinal motility. Recent work has clarified the cellular mechanisms that engender tone and the neurogenic and mechanical stimuli that modulate it but has also highlighted cellular and regional specialisation in these mechanisms within the GI tract. Smooth muscle in all segments of the gut has the capability of latching, i.e. can generate ongoing specific rather than tetanic tone. This is likely modulated by both direct and indirect input from agonists such as acetylcholine and mechanoreceptors, the latter originating in ICC-IM, smooth muscle cells or elements of the ENS. Tonic contraction can occur in the absence of phasic contractions or concurrent with them, and it can modulate wall compliance and the capacity of particular segments, thereby affecting the level of on-flow and mixing, both luminal and adjacent to the mucosa. PURPOSE The review seeks to provide an overview of our understanding of the mechanism by which tone is generated and maintained, highlighting its modulation by neurogenic and mechanical stimuli, its mechanical consequences in the walls of the various segments of the gastrointestinal tract and its contribution to flow and mixing of contained digesta.
Collapse
Affiliation(s)
- R G Lentle
- Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand
| | | | | |
Collapse
|
31
|
Lentle RG, Janssen PWM, Deloubens C, Lim YF, Hulls C, Chambers P. Mucosal microfolds augment mixing at the wall of the distal ileum of the brushtail possum. Neurogastroenterol Motil 2013; 25:881-e700. [PMID: 23941237 DOI: 10.1111/nmo.12203] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 07/19/2013] [Indexed: 02/08/2023]
Abstract
BACKGROUND Recent work suggests that mixing in the small intestine takes place in central luminal and peripheral compartments. However, while movements of villi have been described, the mechanisms by which peripheral mixing are engendered remain unclear. METHODS We examined the disposition and movement of mucosa and associated villi during contractions of the everted terminal ileum of the brushtail possum. We then simulated the effect of these movements on peripheral mixing. KEY RESULTS Compression of the intestinal mucosa by phasic longitudinal or radial contractions created short-lived microfolds, which were of similar scale to the attached villi. The packing density of the villous tips increased in the concavities and decreased on the crests of these microfolds. Simulations showed that these caused liquid digesta to be expelled from, or drawn into, intervillous spaces, significantly augmenting peripheral, but not bulk, luminal mixing. CONCLUSIONS & INFERENCES We describe a mechanism by which peripheral mixing may be engendered by mucosal microfolds without requiring the coordinated contraction of individual villi or groups of villi.
Collapse
Affiliation(s)
- R G Lentle
- Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand
| | | | | | | | | | | |
Collapse
|
32
|
Angeli TR, Du P, Paskaranandavadivel N, Janssen PWM, Beyder A, Lentle RG, Bissett IP, Cheng LK, O'Grady G. The bioelectrical basis and validity of gastrointestinal extracellular slow wave recordings. J Physiol 2013; 591:4567-79. [PMID: 23713030 PMCID: PMC3784199 DOI: 10.1113/jphysiol.2013.254292] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 05/23/2013] [Indexed: 12/27/2022] Open
Abstract
Gastrointestinal extracellular recordings have been a core technique in motility research for a century. However, the bioelectrical basis of extracellular data has recently been challenged by claims that these techniques preferentially assay movement artifacts, cannot reproduce the underlying slow wave kinetics, and misrepresent the true slow wave frequency. These claims motivated this joint experimental-theoretical study, which aimed to define the sources and validity of extracellular potentials. In vivo extracellular recordings and video capture were performed in the porcine jejunum, before and after intra-arterial nifedipine administration. Gastric extracellular recordings were recorded simultaneously using conventional serosal contact and suction electrodes, and biphasic and monophasic extracellular potentials were simulated in a biophysical model. Contractions were abolished by nifedipine, but extracellular slow waves persisted, with unchanged amplitude, downstroke rate, velocity, and downstroke width (P>0.10 for all), at reduced frequency (24% lower; P=0.03). Simultaneous suction and conventional serosal extracellular recordings were identical in phase (frequency and activation-recovery interval), but varied in morphology (monophasic vs. biphasic; downstroke rate and amplitude: P<0.0001). Simulations demonstrated the field contribution of current flow to extracellular potential and quantified the effects of localised depolarisation due to suction pressure on extracellular potential morphology. In sum, these results demonstrate that gastrointestinal extracellular slow wave recordings cannot be explained by motion artifacts, and are of a bioelectrical origin that is highly consistent with the underlying biophysics of slow wave propagation. Motion suppression is shown to be unnecessary as a routine control in in vivo extracellular studies, supporting the validity of the extant gastrointestinal extracellular literature.
Collapse
Affiliation(s)
- Timothy R Angeli
- G. O'Grady: Auckland Bioengineering Institute, Private Bag 92019, Auckland 1142, New Zealand.
| | | | | | | | | | | | | | | | | |
Collapse
|
33
|
de Loubens C, Lentle RG, Love RJ, Hulls C, Janssen PWM. Fluid mechanical consequences of pendular activity, segmentation and pyloric outflow in the proximal duodenum of the rat and the guinea pig. J R Soc Interface 2013; 10:20130027. [PMID: 23536539 PMCID: PMC3645412 DOI: 10.1098/rsif.2013.0027] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 03/06/2013] [Indexed: 11/12/2022] Open
Abstract
We conducted numerical experiments to study the influence of non-propagating longitudinal and circular contractions, i.e. pendular activity and segmentation, respectively, on flow and mixing in the proximal duodenum. A lattice-Boltzmann numerical method was developed to simulate the fluid mechanical consequences for each of 22 randomly selected sequences of high-definition video of real longitudinal and radial contractile activity in the isolated proximal duodenum of the rat and guinea pig. During pendular activity in the rat duodenum, the flow was characterized by regions of high shear rate. Mixing was so governed by shearing deformation of the fluid that increased the interface between adjacent domains and accelerated their inter-diffusion (for diffusion coefficients approx. less than 10(-8) m² s(-1)). When pendular activity was associated with a slow gastric outflow characteristic of post-prandial period, the dispersion was also improved, especially near the walls. Mixing was not promoted by isolated segmentative contractions in the guinea pig duodenum and not notably influenced by pylorus outflow. We concluded that pendular activity generates mixing of viscous fluids 'in situ' and accelerates the diffusive mass transfer, whereas segmentation may be more important in mixing particulate suspensions with high solid volume ratios.
Collapse
Affiliation(s)
- Clément de Loubens
- UMR 782 Génie et Microbiologie des Procédés Alimentaires, INRA, AgroParisTech, CBAI 78850 Thiverval Grignon, France.
| | | | | | | | | |
Collapse
|
34
|
Costa M, Wiklendt L, Arkwright JW, Spencer NJ, Omari T, Brookes SJH, Dinning PG. An experimental method to identify neurogenic and myogenic active mechanical states of intestinal motility. Front Syst Neurosci 2013; 7:7. [PMID: 23596400 PMCID: PMC3622892 DOI: 10.3389/fnsys.2013.00007] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 03/25/2013] [Indexed: 01/28/2023] Open
Abstract
Excitatory and inhibitory enteric neural input to intestinal muscle acting on ongoing myogenic activity determines the rich repertoire of motor patterns involved in digestive function. The enteric neural activity cannot yet be established during movement of intact intestine in vivo or in vitro. We propose the hypothesis that is possible to deduce indirectly, but reliably, the state of activation of the enteric neural input to the muscle from measurements of the mechanical state of the intestinal muscle. The fundamental biomechanical model on which our hypothesis is based is the “three-element model” proposed by Hill. Our strategy is based on simultaneous video recording of changes in diameters and intraluminal pressure with a fiber-optic manometry in isolated segments of rabbit colon. We created a composite spatiotemporal map (DPMap) from diameter (DMap) and pressure changes (PMaps). In this composite map rhythmic myogenic motor patterns can readily be distinguished from the distension induced neural peristaltic contractions. Plotting the diameter changes against corresponding pressure changes at each location of the segment, generates “orbits” that represent the state of the muscle according to its ability to contract or relax actively or undergoing passive changes. With a software developed in MatLab, we identified twelve possible discrete mechanical states and plotted them showing where the intestine actively contracted and relaxed isometrically, auxotonically or isotonically, as well as where passive changes occurred or was quiescent. Clustering all discrete active contractions and relaxations states generated for the first time a spatio-temporal map of where enteric excitatory and inhibitory neural input to the muscle occurs during physiological movements. Recording internal diameter by an impedance probe proved equivalent to measuring external diameter, making possible to further develop similar strategy in vivo and humans.
Collapse
Affiliation(s)
- Marcello Costa
- Department of Human Physiology, School of Medicine, Flinders University Bedford Park, SA, South Australia
| | | | | | | | | | | | | |
Collapse
|
35
|
Lim YF, Williams MAK, Lentle RG, Janssen PWM, Mansel BW, Keen SAJ, Chambers P. An exploration of the microrheological environment around the distal ileal villi and proximal colonic mucosa of the possum (Trichosurus vulpecula). J R Soc Interface 2013; 10:20121008. [PMID: 23389898 PMCID: PMC3627112 DOI: 10.1098/rsif.2012.1008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 01/17/2013] [Indexed: 12/15/2022] Open
Abstract
Multiple particle-tracking techniques were used to quantify the thermally driven motion of ensembles of naked polystyrene (0.5 µm diameter) microbeads in order to determine the microrheological characteristics around the gut mucosa. The microbeads were introduced into living ex vivo preparations of the wall of the terminal ileum and proximal colon of the brushtail possum (Trichosurus vulpecula). The fluid environment surrounding both the ileal villi and colonic mucosa was heterogeneous; probably comprising discrete viscoelastic regions suspended in a continuous Newtonian fluid of viscosity close to water. Neither the viscosity of the continuous phase, the elastic modulus (G') nor the sizes of viscoelastic regions varied significantly between areas within 20 µm and areas more than 20 µm from the villous mucosa nor from the tip to the sides of the villous mucosa. The viscosity of the continuous phase at distances further than 20 µm from the colonic mucosa was greater than that at the same distance from the ileal villous mucosa. Furthermore, the estimated sizes of viscoelastic regions were significantly greater in the colon than in the ileum. These findings validate the sensitivity of the method and call into question previous hypotheses that a contiguous layer of mucus envelops all intestinal mucosa and restricts diffusive mass transfer. Our findings suggest that, in the terminal ileum and colon at least, mixing and mass transfer are governed by more complex dynamics than were previously assumed, perhaps with gel filtration by viscoelastic regions that are suspended in a Newtonian fluid.
Collapse
Affiliation(s)
- Y. F. Lim
- Institute of Food, Nutrition and Human Health, Massey University, Private Bag 11222, Palmerston North, New Zealand
| | - M. A. K. Williams
- Institute of Fundamental Sciences, Massey University, Private Bag 11222, Palmerston North, New Zealand
- Riddet Institute, Massey University, Private Bag 11222, Palmerston North, New Zealand
- MacDiarmid Institute of Advanced Materials and Nanotechnology, Wellington, New Zealand
| | - R. G. Lentle
- Institute of Food, Nutrition and Human Health, Massey University, Private Bag 11222, Palmerston North, New Zealand
- Riddet Institute, Massey University, Private Bag 11222, Palmerston North, New Zealand
| | - P. W. M. Janssen
- Institute of Food, Nutrition and Human Health, Massey University, Private Bag 11222, Palmerston North, New Zealand
| | - B. W. Mansel
- Institute of Fundamental Sciences, Massey University, Private Bag 11222, Palmerston North, New Zealand
- MacDiarmid Institute of Advanced Materials and Nanotechnology, Wellington, New Zealand
| | - S. A. J. Keen
- Institute of Fundamental Sciences, Massey University, Private Bag 11222, Palmerston North, New Zealand
- MacDiarmid Institute of Advanced Materials and Nanotechnology, Wellington, New Zealand
| | - P. Chambers
- Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Private Bag 11222, Palmerston North, New Zealand
| |
Collapse
|
36
|
Janssen PWM, Lentle RG. Spatiotemporal Mapping Techniques for Quantifying Gut Motility. LECTURE NOTES IN COMPUTATIONAL VISION AND BIOMECHANICS 2013. [DOI: 10.1007/978-94-007-6561-0_12] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
|