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Michel K, Kuch B, Dengler S, Demir IE, Zeller F, Schemann M. How big is the little brain in the gut? Neuronal numbers in the enteric nervous system of mice, Guinea pig, and human. Neurogastroenterol Motil 2022; 34:e14440. [PMID: 35929768 DOI: 10.1111/nmo.14440] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 05/23/2022] [Accepted: 07/21/2022] [Indexed: 02/08/2023]
Abstract
BACKGROUND Despite numerous studies on the enteric nervous system (ENS), we lack fundamental knowledge on neuronal densities or total neuron numbers in different species. There are more anecdotal than actual figures on nerve counts. METHODS We used standardized preparation techniques and immunohistochemistry with validated panneuronal markers (human or mouse anti-HuD/C) to determine neuronal densities in specimen from the entire gastrointestinal tract of mice, guinea pig, and humans. In parallel, we measured the dimensions of the gastrointestinal regions in mouse and guinea pig. For humans, we had to rely on literature data. KEY RESULTS The average neuronal densities along the gastrointestinal tract were 35,011 ± 25,017 1/cm2 for the myenteric and 16,685 ± 9098 1/cm2 for the submucous plexus in mice, 24,315 ± 16,627 and 11,850 ± 6122 1/cm2 for guinea pig myenteric and submucous plexus, respectively, and 21,698 ± 9492 and 16,367 ± 5655 1/cm2 for human myenteric and submucous plexus, respectively. The total number of neurons in the ENS was 2.6 million for mice, 14.6 million for guinea pig, and 168 million for human. CONCLUSIONS & INFERENCES This study reports the first comprehensive nerve cell count in mice, guinea pig, and human ENS. Neuronal densities were comparable between the three species and the differences in the total numbers of enteric neurons are likely due to body size and intestinal length. The number of enteric neurons is comparable to the number of neurons in the spinal cord for all three species.
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Affiliation(s)
- Klaus Michel
- Human Biology, Technical University of Munich, Freising, Germany
| | - Birgit Kuch
- Human Biology, Technical University of Munich, Freising, Germany
| | - Sophie Dengler
- Human Biology, Technical University of Munich, Freising, Germany
| | - Ihsan Ekin Demir
- Surgery, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | | | - Michael Schemann
- Human Biology, Technical University of Munich, Freising, Germany
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Pluta R, Jabłoński M, Januszewski S, Czuczwar SJ. Crosstalk between the aging intestinal microflora and the brain in ischemic stroke. Front Aging Neurosci 2022; 14:998049. [PMID: 36275012 PMCID: PMC9582537 DOI: 10.3389/fnagi.2022.998049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 09/22/2022] [Indexed: 11/28/2022] Open
Abstract
Aging is an inevitable phenomenon experienced by animals and humans, and its intensity varies from one individual to another. Aging has been identified as a risk factor for neurodegenerative disorders by influencing the composition of the gut microbiota, microglia activity and cognitive performance. The microbiota-gut-brain axis is a two-way communication path between the gut microbes and the host brain. The aging intestinal microbiota communicates with the brain through secreted metabolites (neurotransmitters), and this phenomenon leads to the destruction of neuronal cells. Numerous external factors, such as living conditions and internal factors related to the age of the host, affect the condition of the intestinal microflora in the form of dysbiosis. Dysbiosis is defined as changes in the composition and function of the gut microflora that affect the pathogenesis, progress, and response to treatment of a disease entity. Dysbiosis occurs when changes in the composition and function of the microbiota exceed the ability of the microflora and its host to restore equilibrium. Dysbiosis leading to dysfunction of the microbiota-gut-brain axis regulates the development and functioning of the host’s nervous, immune, and metabolic systems. Dysbiosis, which causes disturbances in the microbiota-gut-brain axis, is seen with age and with the onset of stroke, and is closely related to the development of risk factors for stroke. The review presents and summarizes the basic elements of the microbiota-gut-brain axis to better understand age-related changes in signaling along the microbiota-gut-brain axis and its dysfunction after stroke. We focused on the relationship between the microbiota-gut-brain axis and aging, emphasizing that all elements of the microbiota-gut-brain axis are subject to age-related changes. We also discuss the interaction between microbiota, microglia and neurons in the aged individuals in the brain after ischemic stroke. Finally, we presented preclinical and clinical studies on the role of the aged microbiota-gut-brain axis in the development of risk factors for stroke and changes in the post-stroke microflora.
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Affiliation(s)
- Ryszard Pluta
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
- *Correspondence: Ryszard Pluta,
| | - Mirosław Jabłoński
- Department of Rehabilitation and Orthopedics, Medical University of Lublin, Lublin, Poland
| | - Sławomir Januszewski
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
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Abstract
The microbiota-gut-brain-axis (MGBA) is a bidirectional communication network between gut microbes and their host. Many environmental and host-related factors affect the gut microbiota. Dysbiosis is defined as compositional and functional alterations of the gut microbiota that contribute to the pathogenesis, progression and treatment responses to disease. Dysbiosis occurs when perturbations of microbiota composition and function exceed the ability of microbiota and its host to restore a symbiotic state. Dysbiosis leads to dysfunctional signaling of the MGBA, which regulates the development and the function of the host's immune, metabolic, and nervous systems. Dysbiosis-induced dysfunction of the MGBA is seen with aging and stroke, and is linked to the development of common stroke risk factors such as obesity, diabetes, and atherosclerosis. Changes in the gut microbiota are also seen in response to stroke, and may impair recovery after injury. This review will begin with an overview of the tools used to study the MGBA with a discussion on limitations and potential experimental confounders. Relevant MGBA components are introduced and summarized for a better understanding of age-related changes in MGBA signaling and its dysfunction after stroke. We will then focus on the relationship between the MGBA and aging, highlighting that all components of the MGBA undergo age-related alterations that can be influenced by or even driven by the gut microbiota. In the final section, the current clinical and preclinical evidence for the role of MGBA signaling in the development of stroke risk factors such as obesity, diabetes, hypertension, and frailty are summarized, as well as microbiota changes with stroke in experimental and clinical populations. We conclude by describing the current understanding of microbiota-based therapies for stroke including the use of pre-/pro-biotics and supplementations with bacterial metabolites. Ongoing progress in this new frontier of biomedical sciences will lead to an improved understanding of the MGBA's impact on human health and disease.
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Affiliation(s)
- Pedram Honarpisheh
- Department of Neurology, University of Texas McGovern Medical School, Houston (P.H., L.D.M.)
| | - Robert M Bryan
- Department of Anesthesiology, Baylor College of Medicine, Houston, TX (R.M.B.)
| | - Louise D McCullough
- Department of Neurology, University of Texas McGovern Medical School, Houston (P.H., L.D.M.)
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Bhattarai C, Poudel PP, Ghosh A, Kalthur SG. Histomorphology of enteric neurons and enteric ganglia in different layers of human fetal colon. J Taibah Univ Med Sci 2022; 17:556-563. [PMID: 35983451 PMCID: PMC9356345 DOI: 10.1016/j.jtumed.2022.01.008] [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: 09/22/2021] [Revised: 01/11/2022] [Accepted: 01/22/2022] [Indexed: 11/28/2022] Open
Abstract
Objective Methods Results Conclusion
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Affiliation(s)
- Chacchu Bhattarai
- Department of Anatomy, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Karnataka, India
- Department of Anatomy, Manipal College of Medical Sciences, Pokhara, Nepal
| | - Phanindra P. Poudel
- Department of Anatomy, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Karnataka, India
- Department of Anatomy, Manipal College of Medical Sciences, Pokhara, Nepal
| | - Arnab Ghosh
- Department of Pathology, Manipal College of Medical Sciences, Pokhara, Nepal
| | - Sneha G. Kalthur
- Department of Anatomy, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Karnataka, India
- Corresponding address: Department of Anatomy, Kasturba Medical College, Manipal, Manipal Academy of Higher Education (MAHE), Karnataka, 576104, India.
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Wang Q, Qi Y, Shen W, Xu J, Wang L, Chen S, Hou T, Si J. The Aged Intestine: Performance and Rejuvenation. Aging Dis 2021; 12:1693-1712. [PMID: 34631215 PMCID: PMC8460310 DOI: 10.14336/ad.2021.0202] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 02/02/2021] [Indexed: 12/12/2022] Open
Abstract
Owing to the growing elderly population, age-related problems are gaining increasing attention from the scientific community. With senescence, the intestine undergoes a spectrum of changes and infirmities that are likely the causes of overall aging. Therefore, identification of the aged intestine and the search for novel strategies to rescue it, are required. Although progress has been made in research on some components of the aged intestine, such as intestinal stem cells, the comprehensive understanding of intestinal aging is still limited, and this restricts the in-depth search for efficient strategies. In this concise review, we discuss several aspects of intestinal aging. More emphasis is placed on the appraisal of current and potential strategies to alleviate intestinal aging, as well as future targets to rejuvenate the aged intestine.
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Affiliation(s)
- Qiwen Wang
- 1Department of Gastroenterology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, Zhejiang Province, China.,2Institute of Gastroenterology, Zhejiang University, Hangzhou 310016, Zhejiang Province, China
| | - Yadong Qi
- 1Department of Gastroenterology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, Zhejiang Province, China.,2Institute of Gastroenterology, Zhejiang University, Hangzhou 310016, Zhejiang Province, China
| | - Weiyi Shen
- 1Department of Gastroenterology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, Zhejiang Province, China.,2Institute of Gastroenterology, Zhejiang University, Hangzhou 310016, Zhejiang Province, China
| | - Jilei Xu
- 1Department of Gastroenterology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, Zhejiang Province, China.,2Institute of Gastroenterology, Zhejiang University, Hangzhou 310016, Zhejiang Province, China
| | - Lan Wang
- 1Department of Gastroenterology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, Zhejiang Province, China.,2Institute of Gastroenterology, Zhejiang University, Hangzhou 310016, Zhejiang Province, China
| | - Shujie Chen
- 1Department of Gastroenterology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, Zhejiang Province, China.,2Institute of Gastroenterology, Zhejiang University, Hangzhou 310016, Zhejiang Province, China
| | - Tongyao Hou
- 1Department of Gastroenterology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, Zhejiang Province, China.,2Institute of Gastroenterology, Zhejiang University, Hangzhou 310016, Zhejiang Province, China
| | - Jianmin Si
- 1Department of Gastroenterology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, Zhejiang Province, China.,2Institute of Gastroenterology, Zhejiang University, Hangzhou 310016, Zhejiang Province, China
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Baker C, Ahmed M, Cheng K, Arciero E, Bhave S, Natalie Ho WL, Goldstein AM, Hotta R. Hypoganglionosis in the gastric antrum causes delayed gastric emptying. Neurogastroenterol Motil 2020; 32:e13766. [PMID: 31773831 PMCID: PMC7182502 DOI: 10.1111/nmo.13766] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 10/03/2019] [Accepted: 10/24/2019] [Indexed: 12/30/2022]
Abstract
BACKGROUND Enteric nervous system (ENS) abnormalities have been implicated in delayed gastric emptying but studies exploring potential treatment options are limited by the lack of an experimental animal model. We examined the ENS abnormalities in the mouse stomach associated with aging, developed a novel model of gastroparesis, and established a new approach to measure gastric emptying. METHODS A modified gastric emptying assay was developed, validated in nNOS -/- mice, and tested in mice at multiple ages. Age-related changes in ENS structure were analyzed by immunohistochemistry. Gastric aganglionosis was generated in Wnt1-iDTR mice using focal administration of diphtheria toxin (DT) into the anterior antral wall. KEY RESULTS Older mice (>5 months) exhibit hypoganglionosis in the gastric antrum and a decreased proportion of nNOS neurons as compared to younger mice (age 5-7 weeks). This was associated with a significant age-dependent decrease in liquid and solid gastric emptying. A novel model of gastric antrum hypoganglionosis was established using neural crest-specific expression of diphtheria toxin receptor. In this model, a significant reduction in liquid and solid gastric emptying is observed. CONCLUSIONS & INFERENCES Older mice exhibit delayed gastric emptying associated with hypoganglionosis and a reduction in nNOS-expressing neurons in the antrum. The causal relationship between antral hypoganglionosis and delayed gastric emptying was verified using a novel experimental model of ENS ablation. This study provides new information regarding the pathogenesis of delayed gastric emptying and provides a robust model system to study this disease and develop novel treatments.
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Affiliation(s)
- Corey Baker
- Department of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, Harvard Medical School, Boston MA 02114
| | - Minhal Ahmed
- Department of Bioengineering, Northeastern University, Boston MA 02115
| | - Katarina Cheng
- Department of Pediatric Surgery, Massachusetts General Hospital, Harvard Medical School, Boston MA 02114
| | - Emily Arciero
- Department of Pediatric Surgery, Massachusetts General Hospital, Harvard Medical School, Boston MA 02114
| | - Sukhada Bhave
- Department of Pediatric Surgery, Massachusetts General Hospital, Harvard Medical School, Boston MA 02114
| | - Wing Lam Natalie Ho
- Department of Pediatric Surgery, Massachusetts General Hospital, Harvard Medical School, Boston MA 02114
| | - Allan M Goldstein
- Department of Pediatric Surgery, Massachusetts General Hospital, Harvard Medical School, Boston MA 02114
| | - Ryo Hotta
- Department of Pediatric Surgery, Massachusetts General Hospital, Harvard Medical School, Boston MA 02114
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Chuang YF, Chen CC, Hsu MJ, Huang NJ, Huang YZ, Chan HL, Chang YJ. Age related changes of the motor excitabilities and central and peripheral muscle strength. J Electromyogr Kinesiol 2018; 44:132-138. [PMID: 30640164 DOI: 10.1016/j.jelekin.2018.12.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 11/09/2018] [Accepted: 12/23/2018] [Indexed: 12/18/2022] Open
Abstract
INTRODUCTION The purpose was to investigate the age effects on central versus peripheral sources of strength, fatigue, and central neural excitabilities. METHODS 42 healthy subjects were recruited as young group (23.73 ± 2.15 years; n = 26) and middle-aged group (57.25 ± 4.57 years; n = 16). Maximum voluntary contraction force (MVC), voluntary activation level (VA), and twitch force of quadriceps were evaluated to represent general, central, and peripheral strengths. Central and peripheral fatigue indexes were evaluated using femoral nerve electrical stimulation. Cortical excitabilities were evaluated using transcranial magnetic stimulation (TMS). RESULTS The middle-aged group had lower MVC and twitch force of quadriceps, but not VA, than young group. No between group differences were found in fatigue indexes. The cortical excitability in middle-aged group was different from young group in paired TMS with inter-stimulus interval of 7 ms. CONCLUSION The age-related strength loss at early stage was primarily caused by peripheral muscular strength. The deviation of central neural excitability can be detected but the activation level was not impaired in middle-age adults.
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Affiliation(s)
- Yu-Fen Chuang
- School of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, and Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan; Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan
| | - Chih-Chung Chen
- School of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, and Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan; Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan
| | - Miao-Ju Hsu
- Department of Physical Therapy, College of Health Science, Kaohsiung Medical University; Department of Physical Medicine and Rehabilitation, and Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Nan-Jing Huang
- School of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, and Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan
| | - Ying-Zu Huang
- Department of Neurology, Chang Gung Memorial Hospital, Linkou, and School of Medicine, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Neuroscience Research Center, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan
| | - Hsiao-Lung Chan
- Neuroscience Research Center, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan; Department of Electrical Engineering, College of Engineering, Chang Gung University, Taoyuan, Taiwan.
| | - Ya-Ju Chang
- School of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, and Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan; Neuroscience Research Center, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan.
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Mari RDB, Stabille SR, de Faria HG, Pereira JNB, Guimarães JP, Marinsek GP, de Souza RR. Balanced Caloric Restriction Minimizes Changes Caused by Aging on the Colonic Myenteric Plexus. J Diet Suppl 2018; 15:285-299. [PMID: 28759281 DOI: 10.1080/19390211.2017.1341446] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Aging can promote significant morphofunctional changes in the gastrointestinal tract (GIT). Regulation of GIT motility is mainly controlled by the myenteric neurons of the enteric nervous system. Actions that aim at decreasing the aging effects in the GIT include those related to diet, with caloric restriction (CR). The CR is achieved by controlling the amount of food or by manipulating the components of the diet. Therefore, the objective of this study was to evaluate different levels of CR on the plasticity of nicotinamide adenine dinucleotide phosphate- (NADPH-) reactive myenteric neurons in the colon of Wistar rats during the aging process using ultrastructural (transmission electron microscopy) and morphoquantitative analysis. Wistar male rats (Rattus norvegicus) were distributed into 4 groups (n = 10/group): C, 6-month-old animals; SR, 18-month-old animals fed a normal diet; CRI, 18-month-old animals fed a 12% CR diet; CRII, 18-month-old animals fed a 31% CR diet. At 6 months of age, animals were transferred to the laboratory animal facility, where they remained until 18 months of age. Animals of the CRI and CRII groups were submitted to CR for 6 months. In the ultrastructural analysis, a disorganization of the periganglionar matrix with the aging was observed, and this characteristic was not observed in the animals that received hypocaloric diet. It was observed that the restriction of 12.5% and 31% of calories in the diet minimized the increase in density and cell profile of the reactive NADPH neurons, increased with age. This type of diet may be adapted against gastrointestinal disturbances that commonly affect aging individuals.
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Affiliation(s)
- Renata de Britto Mari
- a São Paulo State University (Unesp) , Institute of Biosciences , São Vicente , São Paulo , Brazil
| | - Sandra Regina Stabille
- b Department of Morphological Sciences , Maringá State University , Maringá , Paraná , Brazil
| | | | | | - Juliana Plácido Guimarães
- e Laboratory of Marine and Coastal Organisms , Santa Cecilia University , Santos , São Paulo , Brazil
| | | | - Romeu Rodrigues de Souza
- f Department of Physical Education , São Judas Tadeu University , São Paulo , São Paulo , Brazil
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Ng KS, Montes-Adrian NA, Mahns DA, Gladman MA. Quantification and neurochemical coding of the myenteric plexus in humans: No regional variation between the distal colon and rectum. Neurogastroenterol Motil 2018; 30. [PMID: 28836741 DOI: 10.1111/nmo.13193] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 07/28/2017] [Indexed: 02/06/2023]
Abstract
BACKGROUND It remains unclear whether regional variation exists in the human enteric nervous system (ENS) ie, whether intrinsic innervation varies along the gut. Recent classification of gastrointestinal neuropathies has highlighted inadequacies in the quantification of the human ENS. This study used paired wholemounts to accurately quantify and neurochemically code the hindgut myenteric plexus, comparing human distal colon and rectum. METHODS Paired human descending colonic/rectal specimens were procured from 15 patients undergoing anterior resection. Wholemounts of myenteric plexi were triple-immunostained with anti-Hu/NOS/ChAT antibodies. Images were acquired by motorized epifluorescence microscopy, allowing assessment of ganglionic density/size, ganglionic area density, and neuronal density. 'Stretch-corrected' values were calculated using stretched/relaxed tissue dimensions. KEY RESULTS Tile-stitching created a collage with average area 99 300 000 μm2 . Stretch-corrected ganglionic densities were similar (colon: median 510 ganglia/100 mm2 [range 386-1170], rectum: 585 [307-923]; P = .99), as were average ganglionic sizes (colon: 57 593 μm2 [40 301-126 579], rectum: 54 901 [38 701-90 211], P = .36). Ganglionic area density (colon: 11.92 mm2 per 100 mm2 [7.53-18.64], rectum: 9.84 [5.80-17.19], P = .10) and stretch-corrected neuronal densities (colon: 189 neurons/mm2 [117-388], rectum: 182 [89-361], P = .31) were also similar, as were the neurochemical profiles of myenteric ganglia, with comparable proportions of NOS+ and ChAT+ neurons (P > .10). CONCLUSIONS AND INFERENCES This study has revealed similar neuronal and ganglionic densities and neurochemical profiles in human distal colon and rectum. Further investigation of other components of the ENS, incorporating additional immunohistochemical markers are required to confirm that there is no regional variation in the human hindgut ENS.
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Affiliation(s)
- K-S Ng
- Academic Colorectal Unit, Sydney Medical School - Concord, University of Sydney, Concord, New South Wales, Australia
| | - N A Montes-Adrian
- Academic Colorectal Unit, Sydney Medical School - Concord, University of Sydney, Concord, New South Wales, Australia
| | - D A Mahns
- Department of Integrative Physiology, School of Medicine, University of Western Sydney, Campbelltown, New South Wales, Australia
| | - M A Gladman
- Academic Colorectal Unit, Sydney Medical School - Concord, University of Sydney, Concord, New South Wales, Australia.,Enteric Neuroscience and Gastrointestinal Research Group, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia
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Abstract
The number of persons 60 years and older has increased 3-fold between 1950 and 2000. Aging alone does not greatly impact the gastrointestinal (GI) tract. Digestive dysfunction, including esophageal reflux, achalasia, dysphagia, dyspepsia, delayed gastric emptying, constipation, fecal incontinence, and fecal impaction, is a result of the highly prevalent comorbid conditions and the medications with which those conditions are treated. A multidisciplinary approach with the expertise of a geriatrician, gastroenterologist, neurologist, speech pathologist, and physical therapist ensures a comprehensive functional and neurological assessment of the older patient. Radiographic and endoscopic evaluation may be warranted in the evaluation of the symptomatic older patient with consideration given to the risks and benefits of the test being used. Treatment of the digestive dysfunction is aimed at improving health-related quality of life if cure cannot be achieved. Promotion of healthy aging, treatment of comorbid conditions, and avoidance of polypharmacy may prevent some of these digestive disorders. The age-related changes in GI motility, clinical presentation of GI dysmotility, and therapeutic principles in the symptomatic older patient are reviewed here.
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Yu Y, Daly DM, Adam IJ, Kitsanta P, Hill CJ, Wild J, Shorthouse A, Grundy D, Jiang W. Interplay between mast cells, enterochromaffin cells, and sensory signaling in the aging human bowel. Neurogastroenterol Motil 2016; 28:1465-79. [PMID: 27206689 PMCID: PMC5053273 DOI: 10.1111/nmo.12842] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 03/22/2016] [Indexed: 12/20/2022]
Abstract
BACKGROUND Advanced age is associated with a reduction in clinical visceral pain perception. However, the underlying mechanisms remain largely unknown. Previous studies have suggested that an abnormal interplay between mast cells, enterochromaffin (EC) cells, and afferent nerves contribute to nociception in gastrointestinal disorders. The aim of this study was to investigate how aging affects afferent sensitivity and neuro-immune association in the human bowel. METHODS Mechanical and chemical sensitivity of human bowel afferents were examined by ex vivo afferent nerve recordings. Age-related changes in the density of mast cells, EC cells, sensory nerve terminals, and mast cell-nerve micro-anatomical association were investigated by histological and immune staining. KEY RESULTS Human afferents could be broadly classified into subpopulations displaying mechanical and chemical sensitivity, adaptation, chemo-sensitization, and recruitment. Interestingly human bowel afferent nerve sensitivity was attenuated with age. The density of substance P-immunoreactive (SP-IR) nerve varicosities was also reduced with age. In contrast, the density of ileal and colonic mucosal mast cells was increased with age, as was ileal EC cell number. An increased proportion of mast cells was found in close apposition to SP-IR nerves. CONCLUSIONS & INFERENCES Afferent sensitivity in human bowel was reduced with advancing age. Augmentation of mast cells and EC cell numbers and the mast cell-nerve association suggest a compensatory mechanism for sensory neurodegeneration.
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Affiliation(s)
- Y. Yu
- Department of Biomedical ScienceUniversity of SheffieldSheffieldUK
| | - D. M. Daly
- Department of Biomedical ScienceUniversity of SheffieldSheffieldUK
| | - I. J. Adam
- Department of Colorectal Surgical UnitNorthern General HospitalSheffield Teaching HospitalSheffieldUK
| | - P. Kitsanta
- Department of HistopathologyNorthern General HospitalSheffield Teaching HospitalSheffieldUK
| | - C. J. Hill
- Department of Biomedical ScienceUniversity of SheffieldSheffieldUK
| | - J. Wild
- Department of Colorectal Surgical UnitNorthern General HospitalSheffield Teaching HospitalSheffieldUK
| | - A. Shorthouse
- Department of Colorectal Surgical UnitNorthern General HospitalSheffield Teaching HospitalSheffieldUK
| | - D. Grundy
- Department of Biomedical ScienceUniversity of SheffieldSheffieldUK
| | - W. Jiang
- Department of Biomedical ScienceUniversity of SheffieldSheffieldUK
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Lee HJ, Park KS. [Current Status of Translational Research on Constipation]. THE KOREAN JOURNAL OF GASTROENTEROLOGY 2016; 68:143-7. [PMID: 27646583 DOI: 10.4166/kjg.2016.68.3.143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Constipation is one of the most common gastrointestinal disorders with a prevalence up to 16.5% in the general population. It is frequently multifactorial and the pathophysiologic mechanism of constipation is not fully understood. Many preclinical studies of constipation have used animal models. Translational research using these animal models is essential to the investigation of neurogenic and myogenic mechanisms of colon, and to the estimation of the clinical efficacy of new drugs. In this review, we discuss some of the current translational research projects on constipation using animal models.
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Affiliation(s)
- Hyun Jik Lee
- Department of Internal Medicine, Keimyung University School of Medicine, Daegu, Korea
| | - Kyung Sik Park
- Department of Internal Medicine, Keimyung University School of Medicine, Daegu, Korea
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Saffrey MJ. Aging of the mammalian gastrointestinal tract: a complex organ system. AGE (DORDRECHT, NETHERLANDS) 2014; 36:9603. [PMID: 24352567 PMCID: PMC4082571 DOI: 10.1007/s11357-013-9603-2] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 11/25/2013] [Indexed: 05/23/2023]
Abstract
Gastrointestinal disorders are a major cause of morbidity in the elderly population. The gastrointestinal tract is the most complex organ system; its diverse cells perform a range of functions essential to life, not only secretion, digestion, absorption and excretion, but also, very importantly, defence. The gastrointestinal tract acts not only as a barrier to harmful materials and pathogens but also contains the vast number of beneficial bacterial populations that make up the microbiota. Communication between the cells of the gastrointestinal tract and the central nervous and endocrine systems modifies behaviour; the organisms of the microbiota also contribute to this brain-gut-enteric microbiota axis. Age-related physiological changes in the gut are not only common, but also variable, and likely to be influenced by external factors as well as intrinsic aging of the cells involved. The cellular and molecular changes exhibited by the aging gut cells also vary. Aging intestinal smooth muscle cells exhibit a number of changes in the signalling pathways that regulate contraction. There is some evidence for age-associated degeneration of neurons and glia of the enteric nervous system, although enteric neuronal losses are likely not to be nearly as extensive as previously believed. Aging enteric neurons have been shown to exhibit a senescence-associated phenotype. Epithelial stem cells exhibit increased mitochondrial mutation in aging that affects their progeny in the mucosal epithelium. Changes to the microbiota and intestinal immune system during aging are likely to contribute to wider aging of the organism and are increasingly important areas of analysis. How changes of the different cell types of the gut during aging affect the numerous cellular interactions that are essential for normal gut functions will be important areas for future aging research.
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Affiliation(s)
- M Jill Saffrey
- Department of Life Health and Chemical Sciences, Biomedical Research Network, The Open University, Milton Keynes, MK7 6AA, UK,
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Schoffen JPF, Santi Rampazzo AP, Cirilo CP, Zapater MCU, Vicentini FA, Comar JF, Bracht A, Natali MRM. Food restriction enhances oxidative status in aging rats with neuroprotective effects on myenteric neuron populations in the proximal colon. Exp Gerontol 2014; 51:54-64. [DOI: 10.1016/j.exger.2014.01.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Revised: 01/03/2014] [Accepted: 01/07/2014] [Indexed: 01/26/2023]
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Phillips RJ, Martin FN, Billingsley CN, Powley TL. Alpha-synuclein expression patterns in the colonic submucosal plexus of the aging Fischer 344 rat: implications for biopsies in aging and neurodegenerative disorders? Neurogastroenterol Motil 2013; 25:e621-33. [PMID: 23809578 PMCID: PMC3735646 DOI: 10.1111/nmo.12176] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 06/01/2013] [Indexed: 12/17/2022]
Abstract
BACKGROUND This experiment assessed normative expression patterns of alpha-synuclein (SYNC), including ganglionic remodeling and development of SYNC pathologies, in the submucosal plexus (SMP) of the colon during healthy aging. The observations address age-associated changes in bowel function and are relevant to evaluations of SMP-containing colonic biopsies for SYNC or synucleinopathies associated with aging and peripheral neurodegenerative diseases. METHODS Colonic submucosal whole mounts from groups of virgin male Fischer 344 rats (n ≥ 8 per group) at 4, 8, 16, and 24 months of age were processed immunohistochemically for SYNC and the pan-neuronal marker HuC/D. In addition, macrophages immunoreactive for MHCII were examined. Stereological protocols were used to generate unbiased estimates of neuron density, neurons per ganglion, neurons per ganglionic area, and neuron size. KEY RESULTS The protein SYNC was expressed in a subpopulation of SMP neurons, in both nucleus and cytoplasm. The general age-associated pattern across different cell counts was an increase in the number of SYNC+ neurons between 4 and 8 months of age, with progressively decreasing numbers of both SYNC+ and SYNC- neurons over the remaining lifespan. The soma size of SYNC+ neurons increased progressively with age. Aggregated SYNC occurred in the aging SMP, and macrophages with alternatively activated profiles were located adjacent to pathological SYNC deposits, consistent with ongoing phagocytosis. CONCLUSIONS & INFERENCES Changes in SYNC expression with age, including a baseline of accumulating synucleinopathies in the healthy aging SMP, need to be considered when interpreting either functional disturbances or biopsies of the aging colon.
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Affiliation(s)
- Robert J. Phillips
- Corresponding author: Robert J Phillips Purdue University 703 Third Street West Lafayette, IN 47907-2091 Phone: 765-494-6268 Fax: 765-496-1264
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Kapur RP. Counting neurons is not as easy as 'one-two, three'. Neurogastroenterol Motil 2013; 25:549-53. [PMID: 23621607 DOI: 10.1111/nmo.12141] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 03/28/2013] [Indexed: 01/26/2023]
Abstract
An accurate determination of the number of neurons in a segment of bowel is fundamental to establish population norms and identify neurodegenerative conditions, including age-related loss of myenteric ganglion cells. Although the latter phenomenon has been observed by several laboratories in various mammals, in this issue of Neurogastroenterology and Motility, Gamage et al. present evidence that colonic myenteric ganglion cells are maintained in aged mice. These discordant findings prompt a thoughtful consideration, the range of variables affecting the accuracy of neuronal counts and the survival of neuronal populations in aging animals.
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Affiliation(s)
- R. P. Kapur
- Department of Laboratories; Seattle Children's Hospital; University of Washington; Seattle; WA; USA
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Gamage PPKM, Ranson RN, Patel BA, Yeoman MS, Saffrey MJ. Myenteric neuron numbers are maintained in aging mouse distal colon. Neurogastroenterol Motil 2013; 25:e495-e505. [PMID: 23517051 DOI: 10.1111/nmo.12114] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Accepted: 02/15/2013] [Indexed: 12/18/2022]
Abstract
BACKGROUND Age-associated myenteric neuronal loss has been described in several species. In some studies,cholinergic neurons have been reported to be selectively vulnerable, whereas nitrergic neurons are spared. Aging of the mouse enteric nervous system(ENS) and the subtypes of mouse myenteric neurons that may be lost have been little studied. We therefore investigated changes in the numbers of total neurons and two neuronal subpopulations in the mouse distal colon during aging. METHODS Wholemount preparations from 3–4-, 12–13-, 18–19-, and 24–25-month-old C57BL/6 mice were double immunolabeled with HuC/D antibody to identify the total neuronal population and antisera to either calbindin or neuronal nitric oxide synthase (nNOS) to identify myenteric neuronal subpopulations. Samples were analyzed by confocal microscopy. New procedures were employed to ensure unbiased counting and to correct for changes in gut dimensions with age and stretch during sample preparation. The density of nerve fibers in the tertiary plexus was also studied. KEY RESULTS No significant change in numbers of total neurons or of either subpopulation with age was measured, but because of gut growth, the density of myenteric neurons decreased between 3–4 and 12–13 months. The density of nNOS-immunoreactive nerve fibers in the tertiary plexus increased significantly with age, up to 18–19 months. Numerous swollen processes of CB and nNOS-immunoreactive neurons were observed in 18–19- and 24–25-month-old animals. Conclusions &Inferences These results indicate that aging does not result in a loss of myenteric neurons in mouse distal colon at the ages studied, although neurodegenerative changes, which may impact on neuronal function, do occur.
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Affiliation(s)
- P. P. K. M. Gamage
- Department of Life, Health and Chemical Sciences; Biomedical Research Network; Open University; Walton Hall; Milton Keynes; MK7 6AA; UK
| | - R. N. Ranson
- Faculty of Health and Life Sciences; Northumbria University; Ellison Building; Newcastle upon Tyne; NE1 8ST; UK
| | - B. A. Patel
- School of Pharmacy and Biomolecular Sciences, Huxley Building; University of Brighton; Lewes Road; Brighton; BN2 4GJ; UK
| | - M. S. Yeoman
- School of Pharmacy and Biomolecular Sciences, Huxley Building; University of Brighton; Lewes Road; Brighton; BN2 4GJ; UK
| | - M. J. Saffrey
- Department of Life, Health and Chemical Sciences; Biomedical Research Network; Open University; Walton Hall; Milton Keynes; MK7 6AA; UK
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Wang C, Houghton MJ, Gamage PPKM, Collins HE, Patel BA, Yeoman MS, Ranson RN, Saffrey MJ. Changes in the innervation of the mouse internal anal sphincter during aging. Neurogastroenterol Motil 2013; 25:e469-77. [PMID: 23634828 DOI: 10.1111/nmo.12144] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 03/28/2013] [Indexed: 12/20/2022]
Abstract
BACKGROUND The innervation of the mouse internal anal sphincter (IAS) has been little studied, and how it changes during aging has not previously been investigated. The aim of this study was therefore to characterize the distribution and density of subtypes of nerve fibers in the IAS and underlying mucosa in 3-, 12- to 13-, 18- and 24- to 25-month-old male C57BL/6 mice. METHODS Nerve fibers were immunolabeled with antibodies against protein gene product 9.5 (PGP9.5), neuronal nitric oxide synthase (nNOS), vasoactive intestinal polypeptide (VIP), substance P (SP), calcitonin gene-related peptide (CGRP), and calretinin (CR). Immunoreactivity in nerve fibers in the circular muscle and mucosa was quantified using Image J software. KEY RESULTS In young adult (3 month) mice, nNOS-immunoreactive (IR) nerve fibers were densely distributed in the circular muscle, but relatively few in the mucosa; VIP-IR nerve fibers were abundant in the circular muscle and common in the mucosa; SP-IR nerve fibers were common in circular muscle and mucosa; CGRP- and CR-IR nerve fibers were dense in mucosa and sparse in circular muscle. The density of PGP9.5 immunoreactivity (IRY) was not significantly reduced with age, but a significant reduction in nNOS-IRY and SP-IRY with age was found in the IAS circular muscle. Neuronal nitric oxide synthase-, VIP-, and SP-IRY in the anal mucosa were significantly reduced with age. CGRP-IRY in both circular muscle and mucosa was increased in 18-month-old animals. CONCLUSIONS & INFERENCES The density of immunoreactivity of markers for some types of IAS nerve fibers decreases during aging, which may contribute to age-related ano-rectal dysfunction.
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Affiliation(s)
- C Wang
- Department of Life, Health and Chemical Sciences, The Open University, Milton Keynes, UK
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Saffrey MJ. Cellular changes in the enteric nervous system during ageing. Dev Biol 2013; 382:344-55. [PMID: 23537898 DOI: 10.1016/j.ydbio.2013.03.015] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2012] [Revised: 02/22/2013] [Accepted: 03/19/2013] [Indexed: 02/06/2023]
Abstract
The intrinsic neurons of the gut, enteric neurons, have an essential role in gastrointestinal functions. The enteric nervous system is plastic and continues to undergo changes throughout life, as the gut grows and responds to dietary and other environmental changes. Detailed analysis of changes in the ENS during ageing suggests that enteric neurons are more vulnerable to age-related degeneration and cell death than neurons in other parts of the nervous system, although there is considerable variation in the extent and time course of age-related enteric neuronal loss reported in different studies. Specific neuronal subpopulations, particularly cholinergic myenteric neurons, may be more vulnerable than others to age-associated loss or damage. Enteric degeneration and other age-related neuronal changes may contribute to gastrointestinal dysfunction that is common in the elderly population. Evidence suggests that caloric restriction protects against age-associated loss of enteric neurons, but recent advances in the understanding of the effects of the microbiota and the complex interactions between enteric ganglion cells, mucosal immune system and intestinal epithelium indicate that other factors may well influence ageing of enteric neurons. Much remains to be understood about the mechanisms of neuronal loss and damage in the gut, although there is evidence that reactive oxygen species, neurotrophic factor dysregulation and/or activation of a senescence associated phenotype may be involved. To date, there is no evidence for ongoing neurogenesis that might replace dying neurons in the ageing gut, although small local sites of neurogenesis would be difficult to detect. Finally, despite the considerable evidence for enteric neurodegeneration during ageing, and evidence for some physiological changes in animal models, the ageing gut appears to maintain its function remarkably well in animals that exhibit major neuronal loss, indicating that the ENS has considerable functional reserve.
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Affiliation(s)
- M Jill Saffrey
- Department Life, Health & Chemical Sciences, Open University, Walton Hall, Milton Keynes MK7 6AA, United Kingdom.
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20
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Serotonin: from top to bottom. Biogerontology 2012; 14:21-45. [PMID: 23100172 DOI: 10.1007/s10522-012-9406-3] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 10/08/2012] [Indexed: 01/13/2023]
Abstract
Serotonin is a monoamine neurotransmitter, which is phylogenetically conserved in a wide range of species from nematodes to humans. In mammals, age-related changes in serotonin systems are known risk factors of age-related diseases, such as diabetes, faecal incontinence and cardiovascular diseases. A decline in serotonin function with aging would be consistent with observations of age-related changes in behaviours, such as sleep, sexual behaviour and mood all of which are linked to serotonergic function. Despite this little is known about serotonin in relation to aging. This review aims to give a comprehensive analysis of the distribution, function and interactions of serotonin in the brain; gastrointestinal tract; skeletal; vascular and immune systems. It also aims to demonstrate how the function of serotonin is linked to aging and disease pathology in these systems. The regulation of serotonin via microRNAs is also discussed, as are possible applications of serotonergic drugs in aging research and age-related diseases. Furthermore, this review demonstrates that serotonin is potentially involved in whole organism aging through its links with multiple organs, the immune system and microRNA regulation. Methods to investigate these links are discussed.
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Hoyle CHV, Saffrey MJ. Effects of aging on cholinergic neuromuscular transmission in isolated small intestine of ad libitum fed and calorically-restricted rats. Neurogastroenterol Motil 2012; 24:586-92. [PMID: 22435850 DOI: 10.1111/j.1365-2982.2012.01913.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND Age-associated losses of enteric neurons have been described. In rat ileum, myenteric neurons lost during aging have been reported to be predominantly cholinergic, and caloric restriction (CR) has been shown to protect against these losses. Cholinergic myenteric neurons include excitatory motor neurons, so the aim of this work was to determine whether neuronal loss in ad libitum (AL)-fed animals is reflected in dysfunctional cholinergic neuromuscular transmission, and if CR reduces any such dysfunction. METHODS Effects of electrical field stimulation (EFS) and applied acetylcholine (ACh) were examined in the longitudinal muscle of isolated ileal segments from 6-month-old rats and from 13- and 24-month-old rats fed either AL or CR diets. KEY RESULTS Contractile responses to EFS were abolished by atropine and potentiated by the acetylcholinesterase inhibitor, eserine. Frequency-response relationships were not significantly different amongst the three age-groups. Sensitivity to applied ACh, however, was three-fold lower in the oldest animals (P < 0.05). Eserine potentiated responses to ACh; there were no statistically significant differences amongst the sensitivities to ACh in its presence. No significant differences between AL- and CR-fed animals were measured, although variability was less in CR-fed than in AL-fed groups. CONCLUSIONS & INFERENCES The cholinergic system supplying the rat ileum longitudinal muscle did not appear to be impaired in old age. Decreased sensitivity to applied ACh in old tissues may have been due to increased acetylcholinesterase activity. Caloric restriction had no significant effect on responses to EFS or applied ACh. The implications of these results are discussed.
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Affiliation(s)
- C H V Hoyle
- Department of Anatomy and Developmental Biology, University College London, London, UK
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Pascua P, Camello-Almaraz C, Pozo MJ, Martin-Cano FE, Vara E, Fernández-Tresguerres JA, Camello PJ. Aging-induced alterations in female rat colon smooth muscle: the protective effects of hormonal therapy. J Physiol Biochem 2011; 68:255-62. [DOI: 10.1007/s13105-011-0138-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Accepted: 12/03/2011] [Indexed: 10/14/2022]
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Pascua P, Camello-Almaraz C, Camello PJ, Martin-Cano FE, Vara E, Fernandez-Tresguerres JA, Pozo MJ. Melatonin, and to a lesser extent growth hormone, restores colonic smooth muscle physiology in old rats. J Pineal Res 2011; 51:405-15. [PMID: 21649718 DOI: 10.1111/j.1600-079x.2011.00904.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
There is increasing evidence that aging is associated with oxidative damage, inflammation, and apoptosis in different cell types. However, there is limited information regarding aging mechanisms in colon smooth muscle. Old male Wistar rats (22 months) were treated for 10 wks with melatonin or growth hormone (GH). Animals were sacrificed at 24 months of age by decapitation. The colon was dissected and the smooth muscle homogenized. H(2)O(2) and malonyl dialdehyde (MDA) content and catalase and glutathione peroxidase (GPX) activities were determined using colorimetric kits. Expression of nuclear factor kappa B (NF-κB), cyclooxygenase 2 (COX-2), caspase-3, and caspase-9 were determined by Western blot. Aging of colon smooth muscle correlated with an increase in H(2)O(2) and MDA levels when compared with young animals in both proximal and distal segments; these changes were associated with a decrease in the catalase activity in the distal colon. Oxidative stress correlated with an increase in COX-2 and NF-κB expression, which were accompanied by an enhanced expression of the pro-apoptotic enzyme caspase-3 and its upstream enzyme, caspase-9. Melatonin treatment normalized the oxidative, inflammatory, and apoptotic patterns, whereas GH replacement, although effective in reducing oxidative stress in distal colon, did not reverse the age-related inflammation or apoptosis. These results suggest that melatonin should be the treatment of choice to most effectively recover physiological functions in aged colonic smooth muscle.
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Affiliation(s)
- Patricia Pascua
- Department of Physiology, Nursing School, University of Extremadura, Caceres, Spain
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Bitar K, Greenwood-Van Meerveld B, Saad R, Wiley JW. Aging and gastrointestinal neuromuscular function: insights from within and outside the gut. Neurogastroenterol Motil 2011; 23:490-501. [PMID: 21320236 PMCID: PMC3094479 DOI: 10.1111/j.1365-2982.2011.01678.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/06/2022]
Affiliation(s)
- K Bitar
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA Research Administration, VA Medical Center, Oklahoma City, OK, USA
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Wiskur B, Greenwood-Van Meerveld B. The aging colon: the role of enteric neurodegeneration in constipation. Curr Gastroenterol Rep 2011; 12:507-12. [PMID: 20878508 DOI: 10.1007/s11894-010-0139-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Constipation is a common problem in the elderly, and abnormalities in the neural innervation of the colon play a significant role in abnormalities in colonic motility leading to delayed colonic transit. The scope of this review encompasses the latest advances to enhance our understanding of the aging colon with emphasis on enteric neurodegeneration, considered a likely cause for the development of constipation in the aging gut in animal models. Neural innervation of the colon and the effects of aging on intrinsic and extrinsic nerves innervating the colonic smooth muscle is discussed. Evidence supporting the concept that neurologic disorders, such as Parkinson's disease, not only affect the brain but also cause neurodegeneration within the enteric nervous system leading to colonic dysmotility is presented. Further research is needed to investigate the influence of aging on the gastrointestinal tract and to develop novel approaches to therapy directed at protecting the enteric nervous system from neurodegeneration.
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Affiliation(s)
- Brandt Wiskur
- VA Medical Center, Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
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Chronic constipation: lessons from animal studies. Best Pract Res Clin Gastroenterol 2011; 25:59-71. [PMID: 21382579 DOI: 10.1016/j.bpg.2010.12.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 11/23/2010] [Accepted: 12/15/2010] [Indexed: 01/31/2023]
Abstract
Chronic constipation is a highly debilitating condition, affecting a significant proportion of the community. The burden to the health care system and impact on individual patients quality of life is immense. Unfortunately, the aetiology underlying chronic constipation is poorly understood and animal models are being used increasingly to investigate possible intrinsic neurogenic and myogenic mechanisms leading to relevant colonic sensori-motor dysfunction. Recently, major advances have been made in our understanding of the mechanisms that underlie propagating contractions along the large intestine, such as peristalsis and colonic migrating motor complexes in laboratory animals, particularly in guinea-pigs and mice. The first recordings of cyclical propagating contractions along the isolated whole human colon have now also been made. This review will highlight some of these advances and how impairments to these motility patterns may contribute to delayed colonic transit, known to exist in a proportion of patients with chronic constipation.
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Morphological changes in the enteric nervous system of aging and APP23 transgenic mice. Brain Res 2011; 1378:43-53. [PMID: 21241669 DOI: 10.1016/j.brainres.2011.01.030] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 12/22/2010] [Accepted: 01/10/2011] [Indexed: 12/31/2022]
Abstract
Gastrointestinal motility disorders often pose a debilitating problem, especially in elderly patients. In addition, they are frequently occurring co-morbidities in dementia. Whereas a failing enteric nervous system has already been shown to be involved in gastrointestinal motility disorders and in Parkinson's disease, a relationship with the neurodegenerative process of Alzheimer's disease was not yet shown. Therefore, we sought to document quantitative changes in the distribution of βIII-tubulin (general neuronal marker), Substance P, neuronal nitric oxide synthase (NOS), glial fibrillary acidic protein (GFAP) and S-100 immunoreactivity in addition to a qualitative assessment of the presence of amyloid in the small and large intestines of 6, 12 and 18-month-old wild type and transgenic Thy-1-APP23 mice. Amyloid deposits were seen in the vasculature, the mucosal and muscle layer of both heterozygous and wild type mice. Amyloidβ₁₋₄₂ could not be detected, pointing to a different amyloid composition than that found in senile plaques in the mice's brains. The finding of an increased density of βIII-tubulin-, Substance P- and NOS-IR-nerve fibres in heterozygous mice could not undoubtedly be related to amyloid deposition or to an activation of glial cells. Therefore, the alterations at the level of the enteric nervous system and the deposition of amyloid seem not primarily involved in the pathogenesis of Alzheimer's disease. At most they are secondary related to the neurodegenerative process. Additionally, our data could not show extensive neuronal or glial cell loss associated with aging, in contrast to other reports. Instead an increase in S100-IR was observed in senescent mice.
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di Giancamillo A, Vitari F, Bosi G, Savoini G, Domeneghini C. The chemical code of porcine enteric neurons and the number of enteric glial cells are altered by dietary probiotics. Neurogastroenterol Motil 2010; 22:e271-8. [PMID: 20524986 DOI: 10.1111/j.1365-2982.2010.01529.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND The enteric nervous system (ENS) contains chemically coded populations of neurons that serve specific functions for the control of the gastrointestinal tract. The ability of neurons to modify their chemical code in response to luminal changes has recently been discovered. It is possible that enteric neuronal plasticity may sustain the adaptability of the gut to changes in intestinal activity or injury, and that gut neurons may respond to an altered intestinal environment by changing their neuropeptide expression. METHODS We used immunohistochemical methods to investigate the presence and localization of several neuronal populations and enteric glia in both the small (ileum) and large (cecum) intestine of piglets. We assessed their abundance in submucosal and myenteric plexus from animals treated with the probiotic Pediococcus acidilactici compared with untreated controls. KEY RESULTS The treated piglets had a larger number of galanin- and calcitonin gene-related peptide (CGRP)-immunoreactive neurons than controls, but this was limited to the submucosal plexus ganglia of the ileum. Moreover, immunohistochemistry revealed that glial fibrillary acidic protein-positive enteric glial cells were significantly higher in the inner and outer submucosal plexuses of treated animals. CONCLUSIONS & INFERENCES The neuronal and glial changes described here illustrate plasticity of the ENS in response to an altered luminal environment in the gastrointestinal tract.
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Affiliation(s)
- A di Giancamillo
- Department of Veterinary Sciences and Technology for Food Safety, Università degli Studi di Milano, Milan, Italy
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King SK, Sutcliffe JR, Ong SY, Lee M, Koh TL, Wong SQ, Farmer PJ, Peck CJ, Stanton MP, Keck J, Cook DJ, Chow CW, Hutson JM, Southwell BR. Substance P and vasoactive intestinal peptide are reduced in right transverse colon in pediatric slow-transit constipation. Neurogastroenterol Motil 2010; 22:883-92, e234. [PMID: 20529207 DOI: 10.1111/j.1365-2982.2010.01524.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Slow-transit constipation (STC) is recognized in children but the etiology is unknown. Abnormalities in substance P (SP), vasoactive intestinal peptide (VIP) and nitric oxide (NO) have been implicated. The density of nerve fibers in circular muscle containing these transmitters was examined in colon from children with STC and compared to other pediatric and adult samples. METHODS Fluorescence immunohistochemistry using antibodies to NO synthase (NOS), VIP and SP was performed on colonic biopsies (transverse and sigmoid colon) from 33 adults with colorectal cancer, 11 children with normal colonic transit and anorectal retention (NAR) and 51 with chronic constipation and slow motility in the proximal colon (STC). The percentage area of nerve fibers in circular muscle containing each transmitter was quantified in confocal images. KEY RESULTS In colon circular muscle, the percentage area of nerve fibers containing NOS > VIP > SP (6 : 2 : 1). Pediatric groups had a higher density of nerve fibers than adults. In pediatric samples, there were no regional differences in NOS and VIP, while SP nerve fiber density was higher in sigmoid than proximal colon. STC children had lower SP and VIP nerve fiber density in the proximal colon than NAR children. Twenty-three percent of STC children had low SP nerve fiber density. CONCLUSIONS & INFERENCES There are age-related reductions in nerve fiber density in human colon circular muscle. NOS and VIP do not show regional variations, while SP nerve fiber density is higher in distal colon. 1/3 of pediatric STC patients have low SP or VIP nerve fiber density in proximal colon.
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Affiliation(s)
- S K King
- Department of General Surgery, Royal Children's Hospital, Melbourne, Australia
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Harrington AM, Lee M, Ong SY, Yong E, Farmer P, Peck CJ, Chow CW, Hutson JM, Southwell BR. Immunoreactivity for high-affinity choline transporter colocalises with VAChT in human enteric nervous system. Cell Tissue Res 2010; 341:33-48. [PMID: 20490865 DOI: 10.1007/s00441-010-0981-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Accepted: 04/08/2010] [Indexed: 01/08/2023]
Abstract
Cholinergic nerves are identified by labelling molecules in the ACh synthesis, release and destruction pathway. Recently, antibodies against another molecule in this pathway have been developed. Choline reuptake at the synapse occurs via the high-affinity choline transporter (CHT1). CHT1 immunoreactivity is present in cholinergic nerve fibres containing vesicular acetylcholine transporter (VAChT) in the human and rat central nervous system and rat enteric nervous system. We have examined whether CHT1 immunoreactivity is present in nerve fibres in human intestine and whether it is colocalised with markers of cholinergic, tachykinergic or nitrergic circuitry. Human ileum and colon were fixed, sectioned and processed for fluorescence immunohistochemistry with antibodies against CHT1, class III beta-tubulin (TUJ1), synaptophysin, common choline acetyl-transferase (cChAT), VAChT, nitric oxide synthase (NOS), substance P (SP) and vasoactive intestinal peptide (VIP). CHT1 immunoreactivity was present in many nerve fibres in the circular and longitudinal muscle, myenteric and submucosal ganglia, submucosa and mucosa in human colon and ileum and colocalised with immunoreactivity for TUJ1 and synaptophysin confirming its presence in nerve fibres. In nerve fibres in myenteric ganglia and muscle, CHT1 immunoreactivity colocalised with immunoreactivity for VAChT and cChAT. Some colocalisation occurred with SP immunoreactivity, but little with immunoreactivity for VIP or NOS. In the mucosa, CHT1 immunoreactivity colocalised with that for VIP and SP in nerve fibres and was also present in vascular nerve fibres in the submucosa and on epithelial cells on the luminal border of crypts. The colocalisation of CHT1 immunoreactivity with VAChT immunoreactivity in cholinergic enteric nerves in the human bowel thus suggests that CHT1 represents another marker of cholinergic nerves.
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Affiliation(s)
- Andrea M Harrington
- F Douglas Stephens Surgical Research Laboratory, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
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Southwell BR, Koh TL, Wong SQ, King SK, Ong SY, Lee M, Farmer PJ, Peck CJ, Sutcliffe JR, Stanton MP, Keck J, Cook DJ, Chow CW, Hutson JM. Decrease in nerve fibre density in human sigmoid colon circular muscle occurs with growth but not aging. Neurogastroenterol Motil 2010; 22:439-45, e106. [PMID: 19840272 DOI: 10.1111/j.1365-2982.2009.01423.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND Studies in animals suggest that enteric neurons decrease in density or number with increasing age. Neurons containing nitric oxide (NO), vasoactive intestinal peptide (VIP) and Substance P (SP) have been implicated. In human large intestine, NO-utilizing neurons decrease during childhood or early adulthood but it is not known if the innervation of the muscle changes. This study examined the density of nerve fibres containing these transmitters in sigmoid colon circular muscle from children and adults. METHODS Fluorescence immunohistochemistry using antibodies to neuronal NO synthase (nNOS), VIP and SP was performed on sigmoid colon from 18 adults with colorectal cancer, two children with familial adenomatous polyposis, and normal colon from nine children with Hirschsprung's disease. The percentage area of immunoreactive (IR) nerve fibres containing each transmitter in circular muscle was quantified in confocal images. KEY RESULTS In the adult sigmoid colon circular muscle, the percentage area of nerve fibres containing nNOS>VIP>SP (6 : 2 : 1). Paediatric groups had significantly higher percentage area of nerve fibres containing nNOS, VIP or SP-IR than adults, with the decrease in nerve fibre density occurring from birth to 30 years. Circular muscle thickness increased between 12 and 30 years. Total nerve fibre area remained constant, while the muscle increased in thickness. CONCLUSIONS & INFERENCES In human sigmoid colon circular muscle, there are reductions in nNOS-, VIP- and SP-IR nerve fibre density with growth from newborn to late adolescence but little further change with aging. The reduction in nerve density is due to an increase in circular muscle thickness rather than a loss of nerve fibres.
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Affiliation(s)
- B R Southwell
- Department of General Surgery, Royal Children's Hospital, Melbourne, Australia.
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