Impact of interstitial cells of Cajal on slow wave and gallbladder contractility in a guinea pig model of acute cholecystitis

BACKGROUND Impaired interstitial cells of Cajal(ICCs)are central to the pathophysiology of acute cholecystitis(AC).Common bile duct ligation is a common model of AC,producing acute inflammatory changes and decrease in gallbladder contractility.AIM To investigate the origin of slow wave(SW)in the gallbladder and the effect of ICCs on gallbladder contractions during the process of AC.METHODS Methylene blue(MB)with light was used to establish selective impaired ICCs gallbladder tissue.Gallbladder motility was assessed using the frequency of SW and gallbladder muscle contractility in vitro in normal control(NC),AC12h,AC24h,and AC48h groups of guinea pigs.Hematoxylin and eosin and Massonstained gallbladder tissues were scored for inflammatory changes.ICCs pathological changes alterations were estimated using immunohistochemistry and transmission electron microscopy.The alterations of c-Kit,α-SMA,cholecystokinin A receptor(CCKAR),and connexin 43(CX43)were assessed using Western blot.RESULTS Impaired ICCs muscle strips resulted in the decrease in gallbladder SW frequency and contractility.The frequency of SW and gallbladder contractility were significantly lower in the AC12h group.Compared with the NC group,the density and ultrastructure of ICCs were remarkably impaired in the AC groups,especially in the AC12h group.The protein expression levels of c-Kit were significantly decreased in the AC12h group,while CCKAR and CX43 protein expression levels were significantly decreased in the AC48h group.CONCLUSION Loss ICCs could lead to a decrease in gallbladder SW frequency and contractility.The density and ultrastructure of ICCs were clearly impaired in the early stage of AC,while CCKAR and CX43 were significantly reduced at end stage.

Jianpi Qingchang decoction regulates intestinal motility of dextran sulfate sodium-induced colitis through reducing autophagy of interstitial cells of Cajal

AIM To investigate the underlying effect of Jianpi Qingchang decoction(JQD) regulating intestinal motility of dextran sulfate sodium(DSS)-induced colitis in mice. METHODS C57BL/6 mice were randomly divided into four groups: the control group, the DSS group, the JQD group, and the 5-aminosalicylic acid group. Except for the control group, colitis was induced in other groups by giving distilled water containing 5% DSS. Seven days after modeling, the mice were administered corresponding drugs intragastrically. The mice were sacrificed on the 15^(th) day. The disease activity index, macroscopic and histopathologic lesions, and ultrastructure of colon interstitial cells of Cajal(ICC) were observed. The levels of tumor necrosis factor-alpha(TNF-α), interleukin(IL)-1β, IL-10 and interferon gamma(IFN-γ), the expression of nuclear factor-kappa B(NF-κB) p65, c-kit, microtubule-associated protein 1 light chain 3(LC3-Ⅱ) and Beclin-l m RNA, and the colonic smooth muscle tension were assessed. RESULTS Acute inflammation occurred in the mice administered DSS. Compared with the control group, the levels of IL-1β, TNF-α, IL-10 and IFN-γ, the expression of LC3-Ⅱ, Beclin-1 and NF-κB p65 m RNA, and the contractile frequency increased(P < 0.05), the expression of c-kit m RNA and the colonic smooth muscle contractile amplitude decreased in the DSS group(P < 0.05). Compared with the DSS group, the levels of IL-10 and IFN-γ, the expression of c-kit m RNA, and the colonic smooth muscle contractile amplitude increased(P < 0.05), the levels of TNF-α and IL-1β, the expression of LC3-Ⅱ, Beclin-1 and NF-κB p65 m RNA, and the contractile frequency decreased in the JQD group(P < 0.05).CONCLUSION JQD can regulate the intestinal motility of DSS-induced colitis in mice through suppressing intestinal inflammatory cascade reaction, reducing autophagy of ICC, and regulating the network path of ICC/smooth muscle cells.

Interstitial cells of Cajal, the Maestro in health and disease

Interstitial cells of Cajal (ICC) are important players in the symphony of gut motility. They have a very signif icant physiological role orchestrating the normal peristaltic activity of the digestive system. They are the pacemaker cells in gastrointestinal (GI) muscles. Absence, reduction in number or altered integrity of the ICC network may have a dramatic effect on GI system motility. More understanding of ICC physiology will foster advances in physiology of gut motility which will help in a future breakthrough in the pharmacological interventions to restore normal motor function of GI tract. This mini review describes what is known about the physiologic function and role of ICCs in GI system motility and in a variety of GI system motility disorders.

Morphological changes in interstitial cells of Cajal in the deep muscular plexus and enteric motor neurons of the intestine in rats with multiple organ dysfunction syndrome

BACKGROUND：Gastrointestinal motility dysfunction in multiple organ dysfunction syndrome （MODS） has been reported to be related to damage to interstitial cells of Cajal （ICC）. In the entedc nervous system, ICC and smooth muscle cells are connected in a network to form a special functional unit. Many gastrointestinal motility dysfunction diseases are associated with damage to this network.OBJECTIVE：To investigate the morphological changes of intestinal ICC, and to explore the mechanisms underlying gastrointestinal motility dysfunction in rats with MODS.DESIGN, TIME AND SE＇I-FING：The randomized, controlled, experiment was performed at the Central Laboratory of the First Affiliated Hospital of Dalian Medical University of China between June 2007 and March 2009.MATERIALS：Escherichia coli （E. colistrain O127 H6） and bovine serum albumin were purchased from Sigma, USA.METHODS：A total of 40 Wistar rats were equally and randomly divided into MODS group and control group. Suspension of E. coil strain O127 H6 containing BaSO4 and saline were sterilely injected into the abdominal cavity of rats in the MODS and control groups, respectively.MAIN OUTCOME MEASURES：Immunohistochemical double-staining and confocal laser scanning microscopy were used to observe the morphological changes in intestinal cholinergic nerves and ICC in the deep muscular plexus network. Electron microscopy was employed to evaluate the ultrastructural features of ICC in the deep muscular plexus of rats with MODS.RESULTS：Compared with the control group, the distributions and densities of cholinergic/nitrergic newes and ICC in the deep muscular plexus were significantly decreased in the MODS group （P 〈 0.01）. The enteric nerve-ICC network were disrupted.CONCLUSION：There is ultrastructural injury in the ICC in the deep muscular plexus and enteric nerves of the intestine in rats with MODS, which may be associated with the dysmotility of the gastrointestinal tract in MODS.

Hwangryunhaedok-tang induces the depolarization of pacemaker potentials through 5-HT3 and 5-HT4 receptors in cultured murine small intestine interstitial cells of Cajal

AIM To investigate the effects of a water extract of Hwangryunhaedok-tang(HHTE) on the pacemaker potentials of mouse interstitial cells of Cajal(ICCs).METHODS We dissociated ICCs from small intestines and cultured. ICCs were immunologically identified using an antic-kit antibody. We used the whole-cell patch-clamp configuration to record the pacemaker potentials generated by cultured ICCs under the current clamp mode(I = 0). All experiments were performed at 30 ℃-32 ℃RESULTS HHTE dose-dependently depolarized ICC pacemaker potentials. Pretreatment with a 5-HT_3 receptor anta-gonist(Y25130) or a 5-HT_4 receptor antagonist(RS39604) blocked HHTE-induced pacemaker potential depolarizations, whereas pretreatment with a 5-HT7 receptor antagonist(SB269970) did not. Intracellular GDPβS inhibited HHTE-induced pacemaker potential depolarization and pretreatment with a Ca^(2+)-free solution or thapsigargin abolished the pacemaker potentials. In the presence of a Ca^(2+)-free solution or thapsigargin, HHTE did not depolarize ICC pacemaker potentials. In addition, HHTE-induced pacemaker potential depolarization was unaffected by a PKC inhibitor(calphostin C) or a Rho kinase inhibitor(Y27632). Of the four ingredients of HHT, Coptidis Rhizoma and Gardeniae Fructus more effectively inhibited pacemaker potential depolarization.CONCLUSION These results suggest that HHTE dose-dependently depolarizes ICC pacemaker potentials through 5-HT_3 and 5-HT_4 receptors via external and internal Ca^(2+) regulation and via G protein-, PKC-and Rho kinase-independent pathways.

Xiangbinfang granules enhance gastric antrum motility via intramuscular interstitial cells of Cajal in mice

BACKGROUND Interdigestive migrating motor complexes(MMC)produce periodic contractions in the gastrointestinal tract,but the exact mechanism of action still remains unclear.Intramuscular interstitial cells of Cajal(ICC-IM)participate in gastrointestinal hormone and neuromodulation,but the correlation between ICCIM and MMC is also unclear.We found that xiangbinfang granules(XBF)mediated the phase III contraction of MMC.Here,the effects of XBF on gastric antrum motility in W/Wv mice and the effects of ICC-IM on gastric antrum MMC are reported.AIM To observe the effects of ICC-IM on gastric antrum motility and to establish the mechanism of XBF in promoting gastric antrum motility.METHODS The density of c-kit-positive ICC myenteric plexus(ICC-MP)and ICC-IM in the antral muscularis of W/Wv and wild-type(WT)mice was examined by confocal microscopy.The effects of XBF on gastric antrum slow waves in W/Wv and WT mice were recorded by intracellular amplification recording.Micro-strain-gauge force transducers were implanted into the gastric antrum to monitor the MMC and the effect of XBF on gastric antrum motility in conscious W/Wv and WT mice.RESULTS In the gastric antrum of W/Wv mice,c-kit immunoreactivity was significantly reduced,and no ICC-IM network was observed.Spontaneous rhythmic slow waves also appeared in the antrum of W/Wv mice,but the amplitude of the antrum slow wave decreased significantly in W/Wv mice(22.62±2.23 mV vs 2.92±0.52 mV,P<0.0001).MMCs were found in 7 of the 8 WT mice but no complete MMC cycle was found in W/Wv mice.The contractile frequency and amplitude index of the gastric antrum were significantly increased in conscious WT compared to W/Wv mice(frequency,3.53±0.18 cpm vs 1.28±0.12 cpm;amplitude index,23014.26±1798.65 mV·20 min vs 3782.16±407.13 mV·20 min;P<0.0001).XBF depolarized smooth muscle cells of the gastric antrum in WT and W/Wv mice in a dose-dependent manner.Similarly,the gastric antrum motility in WT mice was significantly increased after treatment with XBF 5 mg(P<0.05).Atropine(0.1 mg/kg)blocked the enhancement of XBF in WT and W/Wv mice completely,while tetrodotoxin(0.05 mg/kg)partially inhibited the enhancement by XBF.CONCLUSION ICC-IM participates in the regulation of gastric antrum MMC in mice.XBF induces MMC III-like contractions that enhance gastric antrum motility via ICCIM in mice.

Distribution of nitric oxide synthase, nerve growth factor receptor and interstitial cells of Cajal in hirschsprung's disease and its significance

Objective To investigate the distribution of nitric oxide synthase (NOS), nerve growth factor receptor (NGFR) and interstitial cells of Cajal (ICCs) in Hirschsprung’s disease (HD). Methods The distribution of NOS, NGFR and ICCs was studied by using NADPH diaphorase histochemistry, immunohistochemistry with a monoclonal antibody to human NGFR and the specific polyclonal antibody against c-kit in 8 normal controls and 10 cases of HD. Results NOS and NGFR were abundantly present in the myenteric plexus and in the nerve fibers of musculature. ICCs were intensively distributed in the surface of circular musculature and around the myenteric plexus to form a network in normal control colon. In contrast, NOS and NGFR were scarce or absent in the myenteric plexus and in the nerve fibers of musculature, while the hypertrophic nerve trunks were NGFR positive, ICCs were scarcely distributed and the network was disrupted in the aganglionic colon in HD. Conclusion These findings suggest the involvement of NOS, NGFR and ICCs in the pathophysiology of HD.

Morphological Changes in Network of Enteric Nerve-Interstitial Cells of Cajal-Smooth Muscle Cells in Rats with Multiple Organ Dysfunction Syndrome and Therapeutic Effects of Dachengqi Decoction (大承气汤)

Objective： To observe the effects of Dachengqi Decoction （大承气汤, DCQD） on morphological changes in the network of enteric nerve-interstitial cells of Cajal （ICCs）-smooth muscle cells （SMC） of enteric deep muscular plexuses （DMP） in the rats with multiple organ dysfunction syndrome （MODS）. Methods： One hundred Wistar rats of both sexes weighing 200 to 250 g were randomly divided into the control group, MODS group, and DCQD group. The morphologic changes of enteric nerve-ICC-SMC network in the DMP of intestine was observed using c-Kit and vesicular acetylcholine transporter/neuronal nitric oxide synthase immunohistochemical double-staining with whole-mount preparation technique, confocal laser scanning microscopy, and electron microscopy. Results： Compared with the control group, the distribution and densities of cholinergic/nitrergic nerves and ICC in the DMP （ICC-DMP） of intestine in the MODS group were significantly decreased （P0.01）, and the network of cholinergic nerve-ICC-SMC was disrupted; and the ultrastructural features of ICC-DMP, enteric nerve, and SMC were severely damaged. After treatment with DCQD, the damage in the network of enteric nerve-ICC-SMC was significantly recovered. Compared with the MODS group, the distribution and densities of cholinergic/nitrergic nerves and ICC-DMP in the DCQD group were significantly increased （P0.01）; and the ultrastructural features of ICC-DMP, enteric nerve, smooth muscle cells were significantly recovered. Conclusions： DCQD can improve the gastrointestinal motility in MODS. The mechanism may be related to the effect of repairing the damages in the network of enteric nerve-ICC-SMC.

ICC density predicts bacterial overgrowth in a rat model of post-infectious IBS

AIM:To investigate the interstitial cells of Cajal(ICC) number using a new rat model.METHODS:Sprague-Dawley rats were assigned to two groups.The first group received gavage with Campylobacter jejuni(C.jejuni) 81-176.The second group was gavaged with placebo.Three months after clearance of Campylobacter from the stool,precise segments of duodenum,jejunum,and ileum were ligated in self-contained loops of bowel that were preserved in anaerobic bags.Deep muscular plexus ICC(DMP-ICC) were quantified by two blinded readers assessing the tissue in a random,coded order.The number of ICC per villus was compared among controls,Campylobacter recovered rats without small intestinal bacterial overgrowth(SIBO),and Campylobacter recovered rats with SIBO.RESULTS:Three months after recovery,27% of rats gavaged with C.jejuni had SIBO.The rats with SIBO had a lower number of DMP-ICC than controls in the jejunum and ileum.Additionally there appeared to be a density threshold of 0.12 DMP-ICC/villus that was associated with SIBO.If ileal density of DMP-ICC was < 0.12 ICC/villus,54% of rats had SIBO compared to 9% among ileal sections with > 0.12(P<0.05).If the density of ICC was < 0.12 DMP-ICC/villus in more than one location of the bowel,88% of these had SIBO compared to 6% in those who did not(P<0.001).CONCLUSION:In this post-infectious rat model,the development of SIBO appears to be associated with a reduction in DMP-ICC.Further study of this rat model might help understand the pathophysiology of postinfectious irritable bowel syndrome.

Protective Effect of Tangshen Formula on Interstitial Cells of Cajal in Colon of Diabetic Rats

Objective:To explore the effect of Tangshen Formula(TSF),a Chinese herbal medicine,on interstitial cells of Cajal(ICC)in the colon of diabetic rats.Methods:Fifty-four male Wistar rats were randomly divided into normal control(NC,n=14)and high-fat diet(HFD)groups(n=40).After 6 weeks,the rats in the HFD group were injected intraperitoneally streptozotocin once(30 mg/kg).Thirty rats with fasting blood glucose higher than 11.7 mmol/L were randomly divided into diabetes(DM)and TSF groups,15 rats in each group.Rats in the NC and DM groups were intragastrically administered with saline,and those in the TSF group were given with TSF(2.4 g/kg)once daily for 20 weeks.Expression levels of Bax,Bcl-2,and caspase-3 in colonic smooth muscle layer were measured by Western blotting and immunohistochemical staining.The number of ICC was determined by immunohistochemical staining.Immunofluorescence was used for analyzing the ratio of classically activated macrophages(M1)and alternatively activated macrophages(M2)to total macrophages.Electron microscopy was used to observe the epithelial ultrastructure and junctions.Results:TSF appeared to partially prevented loss of ICC in DM rats(P<0.05).Compared with the NC group,expression levels of Bcl-2,Bax,caspase-3,and TNF-αas well as the ratio of M1 to total macrophages increased in DM rats(all P<0.05),and the ratio of M2 to total macrophages decreased(P<0.05 or P<0.01).Compared with the DM group,TSF decreased the expression levels of abovementioned proteins and restore M2 to total macrophages ratio(P<0.05 or P<0.01).TSF appeared to attenuate the ultrastructural changes of epithelia and improve the tight and desmosome junctions between epithelia reduced in the DM rats.Conclusions:Reduced number of ICC in DM rats may be associated with damage of the intestinal barrier.The protective effects of TSF on ICC may be through repair of the epithelial junctions,which attenuates inflammation and inflammation-initiated apoptosis in colon of DM rats.

Shouhui Tongbian Capsule in treatment of constipation: Treatment and mechanism development

Constipation is common in the diseases of the digestive system in clinics.With the change in diet structure and the increase in life pressure,the prevalence rate increases year by year.In traditional Chinese medicine(TCM),the location of the disease of constipation is in the large intestine,which is related to the dysfunction of lung,spleen,liver,kidney and other viscera.Its pathogenesis is conductive dysfunction of large intestine.Based on the theory,Shouhui Tongbian Capsule(SHTB)is composed of eight traditional Chinese medicines,including Polygoni multiflori Radix(Heshouwu in Chinese),Aloe(Luhui in Chinese),Cassiae Semen(Juemingzi in Chinese),Ginseng Radix et Rhizoma(Renshen in Chinese),Lycii Fructus(Gouqizi in Chinese),Asini Corii Colla(Ejiao in Chinese),Aurantii Fructus Immaturus(Zhishi in Chinese),and Atractylodis Macrocephalae Rhizoma(Baizhu in Chinese),which could help to release excessive turbid,and nourishing yin and supplementing qi in the treatment.This study has been carried out to review the latest advances of SHTB in the treatment of constipation.The results showed that significant effect of SHTB was found in the treatment of constipation,such as functional constipation,and constipation associated with tumor chemotherapy,colitis,type 2 diabetes and chronic cardiac failure.Besides,obvious adverse reactions were not observed.SHTB could effectively treat five types of constipation,provide direction for the future exploration of SHTB in the treatment of other types of constipation。

Therapy-refractory gastrointestinal motility disorder in a child with c-kit mutations

Constipation and fecal impaction are frequent and distressing complaints in pediatric gastroenterology. Especially in neurologically handicapped children, treatment of severe forms of slow-transit constipation (STC) can be difficult. In the majority of cases, STC is of unknown etiology. However, in recent years, there is growing evidence that interstitial cells of Cajal (ICCs), which serve as electrical pacemakers and generate spontaneous electrical slow waves in the gastrointestinal tract, might play an important role in the pathophysiology of STC. It remains unclear whether morphological ICC alterations seen in affected patients are based on congenital developmental anomalies, or whether they are a consequence of long-term constipation with secondary damage of the gastrointestinal nervous system. To the best of our knowledge, we present the first case of a patient with histological alterations in ICC morphology who displayed multiple alterations of c-kit at the level of mRNA. The protein encoded by c-kit is the receptor tyrosine kinase Kit (CD117), which is crucial for development and function of ICCs. Therefore, these findings provide a new explanation for congenital alterations of ICC development that result in gastrointestinal motility disorders.