Enteric neuromuscular pathology update

The recent development of consensus guidelines for the preparation and staining of tissues, the publication of the London Classification, and reviews of what is normal in the enteric neuromusculature have been significant steps forward in this field. Increased accessibility to full-thickness biopsies of the bowel wall facilitated by advances in laparoscopic surgery have also played a part in making the decision to ask for a tissue diagnosis easier. Better antibodies for immunohistochemistry and a better understanding of disease processes at work, such as those seen in filamin mutations, all help inform the range of information that can be gleaned from what is usually a very limited sample. Clinical phenotyping remains difficult in many patients, but the availability of specialist pathologic review and the standardization of staining between laboratories are leading to better defined histologic phenotypes, that inform, in turn, possible biological processes at work in these patients. In many instances, a diagnosis may come to light only after some time, and the retention of pathologic samples in paraffin wax, as is standard practice in most laboratories, is of great value in reassessing samples, often after many years, in the light of new advances. The highest quality information, and the best answer for the patient, is, as ever, achieved by close working relationships and excellent communication between clinicians and pathologists.     

Cajal间质细胞与胃肠动力关系的研究进展

Cajal间质细胞(interstitial cells of Cajal,ICC)是胃肠慢波的起搏细胞,具有产生慢波、传导慢波电位、调节神经递质等功能,是调节胃肠动力的重要环节。ICC在维持正常胃肠动力方面发挥着重要作用,同时其形态、数量及分布的改变会导致多种胃肠动力障碍性疾病。一些以ICC为靶向治疗胃肠动力性疾病药物的研究也取得一定进展。本文就近年来ICC与胃肠动力关系的研究进展作一概述。     

针刺对功能性便秘ENS-ICC调节机制的研究进展

功能性便秘(functional constipation,FC)是临床常见病和多发病,其病因和发病机制尚不十分清楚,存在多种学说.实验研究表明,"泻药性结肠"动物模型结肠表现为肠神经系统神经丛超微结构、多种受体与ICC表达的异常.我们通过检索和分析近年来针刺治疗FC的实验研究文献,发现目前针刺对FC的调节机制的研究偏于单一化,多种机制之间的调控关系没有进行深入研究.今后的研究应侧重针刺对各机制之间相互关系的阐释以及对其关键机制的探讨,使针刺作用机制的研究进一步深入,从而更好地服务于临床.     

胃肠道神经-Cajal间质细胞-平滑肌网络研究进展

Cajal间质细胞是胃肠起搏细胞,并具有传导神经递质的作用.近年来的研究表明胃肠神经-ICC-平滑肌网络间存在密切的联系.此文就近期胃肠神经-ICC-平滑肌网络的研究进展作一综述.     

Aging of the mammalian gastrointestinal tract: a complex organ system

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.     

Slow transit colon constipation is not related to the number of interstitial cells of Cajal

Background and aims Recent studies have demonstrated decreased numbers of interstitial cells of Cajal in patients suffering from severe chronic constipation as measured by c-Kit (CD117) and CD34 immunohistology. In this study, we wished to determine whether there were abnormalities in the number of neurons of the Auerbach's plexus, their CD117 and CD34 immunoreactivity, or the thickness of colon wall sections in patients with refractory slow transit colonic constipation as compared with control subjects.Patients and methods Specimens from 13 patients who had undergone subtotal colectomy for severe chronic constipation refractory to medical treatment were compared with normal controls. Enteric neurons of Auerbach's plexus were counted, and thickness of the circular and longitudinal layer of the muscularis externa as well as total muscularis externa was measured. Quantitative assessment of anti-CD117 and anti-CD34 immunoreactivity was performed using an Automated Cellular Imaging System and expressed as fractional scores.Results Except for a decreased circular muscle layer thickness in the constipated patients, no statistically significant differences were observed between the two groups. In particular, there was no relationship between CD117/CD34 fractional staining score and the duration or severity of disease, despite the selection of highly symptomatic individuals requiring colonic resection.Conclusion Using quantitative immunohistochemistry for CD117/CD34, we could not detect a relationship between fractional CD117/CD34 staining score and chronic constipation as compared to controls.     

Differential changes in intrinsic innervation and interstitial cells of Cajal in small bowel atresia in newborns

AIM: To investigate morphological changes of the enteric nervous system (ENS) and the interstitial cells of Cajal (ICCs) in small bowel atresia.METHODS: Resected small bowel specimens from affected patients (n = 7) were divided into three parts (proximal, atretic, distal). Standard histology and enzyme immunohistochemistry anti-S100, anti-protein gene product (PGP) 9.5, anti-neurofilament (NF), antic-kit-receptor (CD117) was carried out on conventional paraffin sections of the proximal and distal part. RESULTS: The neuronal and glial markers (PGP 9.5, NF, S-100) were expressed in hypertrophied ganglia and nerve fibres within the myenteric and submucosal plexuses. Furthermore, the submucous plexus contained typical giant ganglia. The innervation pattern of the proximal bowel resembled intestinal neuronal dysplasia. The density of myenteric ICCs was clearly reduced in the proximal bowel, whereas a moderate number of muscular ICCs were found. The anti-CD117 immunore- action revealed additional numerous mast cells. The distal bowel demonstrated normal morphology and density of the ENS, the ICCs and the mast cells.CONCLUSION: The proximal and distal bowel in small bowel atresia revealed clear changes in morphology and density of the ENS and ICCs.     

Characterization of smooth muscle,enteric nerve,interstitial cells of Cajal,and fibroblast-like cells in the gastric musculature of patients with diabetes mellitus

AIM To investigate histologic abnormalities in the gastric smooth muscle of patients with diabetes mellitus(DM).METHODS Full-thickness gastric specimens were obtained from patients undergoing surgery for gastric cancer. HE stain and Masson's Trichrome stain were performed to assess the degree of fibrosis. Immunohistochemical staining using various antibodies was also performed [antibodies against protein gene product 9.5(PGP9.5), neuronal nitric oxide synthase(n NOS), vasoactive intestinal peptide(VIP), neurokinin-1(NK1) receptor, c-Kit, and platelet-derived growth factor receptor-alpha,(PDGFRα)]. Immunofluorescent staining and evaluation with confocal microscopy were also conducted.RESULTS Twenty-six controls and 35 diabetic patients(21 shortduration patients and 14 long-duration patients) were included. There were no significant differences in basic demographics between the two groups except in mean body mass index(BMI)(higher in the DM group). Proportions of moderate-to-severe intercellular fibrosis in the muscle layer were significantly higher in the DM group than in the control group(P 0.01). On immunohistochemical staining, c-Kit- and PDGFRα-positive immunoreactivity were significantly decreased in the DM group compared with the control group(P 0.05). There were no statistically significant differences in PGP9.5, n NOS, VIP, and neurokinin 1 expression. On immunofluorescent staining, cellularity of interstitial cells of Cajal(ICC) was observed to decrease with increasing duration of DM.CONCLUSION Our study suggests that increased intercellular fibrosis, loss of ICC, and loss of fibroblast-like cells are found in the smooth muscle of DM patients. These abnormalities may contribute to changes in gastric motor activity in patients with DM.     

小鼠空肠cajal间质细胞的分离与培养

目的研究CD1小鼠空肠cajal间质细胞(ICC)的分离和培养方法,为进一步研究其生理学特征提供基础。方法无菌条件下取小鼠空肠组织,分离出平滑肌肌条,采取组织块培养法,在24孔培养板中进行原代培养,光镜下观察其形态,用荧光标记的特异性C_Kit抗体进行鉴定。结果倒置显微镜下观察ICC有多个突起,并有次级分支,相互之间形成网络。免疫荧光法可见ICC呈阳性。结论组织块培养法可以简便、有效地培养ICC。所培养的ICC细胞生物学特性有待进一步研究。     

Chronic intestinal pseudo-obstruction: clinical features, diagnosis, and therapy

CIPO is the very “tip of the iceberg” of functional gastrointestinal disorders, being a rare and frequently misdiagnosed condition characterized by an overall poor outcome. Diagnosis should be based on clinical features, natural history and radiologic findings. There is no cure for CIPO and management strategies include a wide array of nutritional, pharmacologic, and surgical options which are directed to minimize malnutrition, promote gut motility and reduce complications of stasis (ie, bacterial overgrowth). Pain may become so severe to necessitate major analgesic drugs. Underlying causes of secondary CIPO should be thoroughly investigated and, if detected, treated accordingly. Surgery should be indicated only in a highly selected, well characterized subset of patients, while isolated intestinal or multivisceral transplantation is a rescue therapy only in those patients with intestinal failure unsuitable for or unable to continue with TPN/HPN. Future perspectives in CIPO will be directed toward an accurate genomic/proteomic phenotying of these rare, challenging patients. Unveiling causative mechanisms of neuro-ICC-muscular abnormalities will pave the way for targeted therapeutic options for patients with CIPO.     

糖尿病大鼠胃肠功能紊乱时结肠组织中Cajal间质细胞的表达

目的观察糖尿病大鼠胃肠功能紊乱时结肠组织内Cajal间质细胞的分布及表达变化,探讨Cajal间质细胞在糖尿病胃肠功能紊乱发病机制中的作用。方法30只SD大鼠随机分为两组,糖尿病组20只,正常对照组10只。糖尿病组大鼠用链脲佐菌素单剂量腹腔注射建立糖尿病模型,对照组注射等量枸橼酸缓冲液。两组大鼠饲养6周后处死,计算胃肠推进率并且收集结肠组织标本。用免疫组化方法观察Cajal间质细胞在两组大鼠结肠组织内的分布和表达,用W estern b lot方法检测c-k it蛋白在两组大鼠结肠内的表达。结果糖尿病组大鼠胃肠推进率较对照组明显降低（P〈0.05）。免疫组化和W estern b lot检测都显示糖尿病大鼠结肠组织内Cajal间质细胞的表达较正常大鼠明显减少（P均〈0.05）。结论糖尿病大鼠结肠组织内Cajal间质细胞表达减少,推测与糖尿病大鼠胃肠功能紊乱有一定相关性。     

Clinical characteristics of chronic idiopathic intestinal pseudo-obstruction in adults

Background—Chronic idiopathic intestinalpseudo-obstruction, a syndrome of ineffectual motility due to a primarydisorder of enteric nerve or muscle, is rare.
Aims—To determine the clinical spectrum,underlying pathologies, response to treatments, and prognosis in aconsecutive unselected group of patients.
Methods—Cross sectional study of all patientswith clinical and radiological features of intestinal obstruction inthe absence of organic obstruction, associated with dilated smallintestine (with or without dilated large intestine), being activelymanaged in one tertiary referral centre at one time.
Results—Twenty patients (11 men and nine women,median age 43 years, range 22-67) fulfilled the diganostic criteria.Median age at onset of symptoms was 17 years (range two weeks to 59 years). Two patients had an autosomally dominant inherited visceralmyopathy. Major presenting symptoms were pain (80%), vomiting (75%),constipation (40%), and diarrhoea (20%). Eighteen patients requiredabdominal surgery, and a further patient had a full thickness rectalbiopsy. The mean time interval from symptom onset to first operationwas 5.8 years. Histology showed visceral myopathy in 13, visceral neuropathy in three, and was indeterminate in three. In the one otherpatient small bowel motility studies were suggestive of neuropathy. Twopatients died within two years of symptom onset, one from generalisedthrombosis and the other from an inflammatory myopathy. Of theremaining 18 patients, eight were nutritionally independent ofsupplements, two had gastrostomy or jejunostomy feeds, and eight werereceiving home parenteral nutrition. Five patients were opiatedependent, only one patient had benefited from prokinetic drug therapy,and five patients required formal psychological intervention and support.
Conclusions—In a referral setting visceralmyopathy is the most common diagnosis in this heterogeneous syndrome,the course of the illness is usually prolonged, and prokinetic drugtherapies are not usually helpful. Ongoing management problems includepain relief and nutritional support.

Keywords:adult; intestinal; pseudo-obstruction; myopathy; neuropathy

     

肥大细胞缺陷动物在胃肠功能障碍研究中的应用

大量研究表明肥大细胞在胃肠功能障碍等疾病的发生中起重要作用，因此肥大细胞缺陷动物的引入，对其发病机制的研究具有重要意义。但同时由于目前的肥大细胞缺陷动物也存在与调节消化道运动功能有关细胞的缺失一卡哈尔细胞的缺失，这给肥大细胞缺陷动物的应用带来一定的局限性。本文对肥大细胞缺陷的机制、各种肥大细胞缺陷动物的特点、在胃肠功能障碍研究中的应用以及存在的局限性进行综述。     

Cajal间质细胞在胃癌胃肠动力障碍中作用的实验研究

目的 探讨Cajal间质细胞在胃癌胃肠动力障碍发病机制中的作用.方法 将20只裸鼠随机分为正常对照组、胃癌组,每组各10只.将人胃癌SGC-7901细胞悬液皮下接种于胃癌组裸鼠背部,当接种部位肿瘤长至最大径4～5 mm时作为胃癌动物模型.采用文献报道的方法,取幽门环形肌和下食管括约肌肌条,记录正常对照组、胃癌组幽门环形肌和下食管括约肌的机械收缩运动的变化.采用免疫组化的方法,比较正常对照组、胃癌组胃壁Cajal间质细胞含量及形态学改变.结果 与正常对照组相比,胃癌组大鼠幽门环形肌和下食管括约肌肌条肌肉张力和收缩振幅明显降低（P＜0.01）.免疫组化染色显示,胃癌组Cajal间质细胞在胃体及胃窦的分布稀疏,数量减少,且细胞突起变少、变钝.结论 胃肠Cajal间质细胞异常变化可能是胃癌出现胃肠动力障碍性疾病的重要发病机制.     

Anatomically realistic multiscale models of normal and abnormal gastrointestinal electrical activity

One of the major aims of the Tnternational Union of Physiological Sciences (IUPS) Physiome Project is to develop multiscale mathematical and computer models that can be used to help understand human health.We present here a small facet of this broad plan that applies to the gastrointestinal system. Specifically,we present an anatomically and physiologically based modelling framework that is capable of simulating normal and pathological electrical activity within the stomach and small intestine. The continuum models used within this framework have been created using anatomical information derived from common medical imaging modalities and data from the Visible Human Project. These models explicitly incorporate the various smooth muscle layers and networks of interstitial cells of Cajal (ICC) that are known to exist within the walls of the stomach and small bowel. Electrical activity within individual ICCs and smooth muscle cells is simulated using a previously published simplified representation of the cell level electrical activity. This simulated cell level activity is incorporated into a bidomain representation of the tissue, allowing electrical activity of the entire stomach or intestine to be simulated in the anatomically derived models. This electrical modelling framework successfully replicates many of the qualitative features of the slow wave activity within the stomach and intestine and has also been used to investigate activity associated with functional uncoupling of the stomach.     

Loss of interstitial cells and a fibromuscular layer on the luminal side of the colonic circular muscle presenting as megacolon in an adult patient

BACKGROUND: Animal studies have shown that the neuromuscular structures on the luminal side of the colonic circular muscle coordinate circular muscle activity. These structures have been identified by electron microscopy in the normal human colon, but have never been thoroughly studied in patients with acquired intestinal hypoganglionosis. AIMS: To perform histological, immunocytochemical, and electron microscopic examinations of the colon of a patient with acquired intestinal hypoganglionosis presenting as megacolon. PATIENT: A 32 year old man with a one year history of constipation and abdominal distention, a massively dilated ascending and transverse colon, and a normal calibre rectum and descending and sigmoid colon. He had a high titre of circulating serum anti-neuronal nuclear antibodies. METHODS: Histology, immunocytochemistry (for neurofilaments, neurone specific enolase, synaptophysin, glial fibrillar acidic protein, S100 protein, and smooth muscle alpha-actin), and electron microscopic examinations on the resected colon. RESULTS: The number of ganglion cells and nerve trunks was decreased throughout the colon. Disruption of the neural network and a loss of interstitial cells of Cajal were observed on the luminal side of the circular muscle; in their place, the non-dilated colon contained a hypertrophic fibromuscular layer. CONCLUSIONS: Striking architectural alterations occurred at the site regarded as the source of the coordination of colonic circular muscle activity in an adult patient with acquired intestinal hypoganglionosis presenting as megacolon.     

Comparison of different methods of intestinal obstruction in a rat model

AIM:To investigate different methods of creating incomplete intestinal obstruction in a rat model and to compare their electrophysiologic,morphologic and histologic characteristics. METHODS:Rat ileum was partially obstructed by the respective application of:braided silk(penetrated the mesentery and surrounded intestine);half ligation (penetrated directly and ligated 1/2 cross-section of the intestine);wide pipe(6 mm in width,surrounded the intestine);narrow pipe(2 mm in width,surrounded the intestine).A control was also included(no obstruction). Various behavioral and electrophysiologic variables, as well as morphologic and immunohistochemical observations were recorded by blinded investigators at different time points(12,24,48,72 h),including daily general condition,ileal wet weight and circumference, macromorphous and micromorphous intestine,bowel movement capability in vivo and in vitro,slow wave and neural electrical activity,and the number of c-Kit positive interstitial cells of Cajal(ICC). RESULTS:Despite being of a similar general condition, these methods resulted in different levels of obstruction in each group compared with the control at different time points(12,24,48,72 h).However,these fields of the wide pipe rat showed significantly differences when compared with the other three obstructed groups at 12 to 72 h,including macroscopic and histological presentation,intestinal transit ratio and contractility,circumference and wet weight,amplitude and frequency of nerve electrical discharge and slow wave,and ICC numbers(all P<0.01). CONCLUSION:The wide pipe rat method is significantly more reliable and stable than the other methods of obstruction,demonstrating that use of the wide pipe method can be a useful model of incomplete intestinal obstruction.