Morphology of the interstitial cells of Cajal of the human ileum from foetal to neonatal life

Prenatal ultrasound markers for prediction of complex gastroschisis-single-center retrospective cohort study

OBJECTIVE

To evaluate prenatal ultrasound markers for distinguishing simple gastroschisis (sGS) from complex gastroschisis (cGS) and identifying fetuses at risk of complications.

STUDY DESIGN

A retrospective cohort study analyzed 61 fetuses with isolated gastroschisis at a tertiary center from 2011 to 2021, utilizing serial ultrasounds from 14 to 35 weeks' gestation. A general linear model, quantile regression, and logistic regression assessed ultrasound markers, fetal weeks, and gastroschisis risk, yielding predictive models.

RESULTS

IABL dilatation showed the highest PPV but low NPV. Non-free floating bowel loops (NFFBL) indicated the best PPV to NPV ratio. Combinations of markers yielded the highest predictive value for cGS. EABL collapsed and non-free floating bowel loops were significant, consistent risk factors.

CONCLUSIONS

Prenatal ultrasounds can predict cGS risk, particularly using IABL dilatation and NFFBL as markers. Accurate assessment requires considering gestational age, qualitative symptoms, emphasizing experienced perinatologists' role and monitoring, particularly after 30 weeks of gestation.

Neural crest derivatives and neuroendocrine cells in the gut of anencephalic and fetuses without congenital defects

BACKGROUND

The enteric nervous system (ENS), a component of the peripheral nervous system in the intestinal walls, regulates motility, secretion, absorption, and blood flow. Neural crest (NC) migration, fundamental for ENS development, may be altered by central nervous system development alterations, such as neural tube defects (NTD). Intestinal innervation anomalies have been correlated to NTD. We aim to describe the ENS on a fetus with NTD and fetuses without congenital defects (FWCD).

CASES

Two male and four female FWCD, 18-20 weeks-gestation (WG), and a 25 WG female anencephalic fetus. Samples from the pancreatoduodenal groove, jejunum, cecum, rectum, and appendix were analyzed by immunohistochemistry. Nervous plexuses were marked with Neuron-specific enolase and S-100; enteric glial cells with CD56; neuroendocrine cells with chromogranin and synaptophysin, and interstitial cells of Cajal (ICC) with CD117.

RESULTS AND CONCLUSION

The anencephalic fetus presented a rudimentary brainstem with a cerebellum. Partial frontal, temporal, and occipital bones were found. A large atrial septal defect, an enlarged kidney with a duplex collecting system and a single adrenal gland were found. NSE, S100, and CD56, showed the presence of the myenteric and submucous plexuses of the ENS; scarce interplexus reactivity may indicate inadequate development. Pancreatic and gut neuroendocrine cells, identified with chromogranin and CD56, showed that the enteroendocrine system is present. Findings on FWCD using these markers are consistent with literature descriptions. Vagal NC migration appears to be unaffected despite the presence of anencephaly, although maturation of the ENS may be altered.

The Telocytes: Ten Years after Their Introduction in the Scientific Literature. An Update on Their Morphology, Distribution, and Potential Roles in the Gut

Ten years ago, the term 'telocyte' was introduced in the scientific literature to describe a 'new' cell type described in the connective tissue of several organs by Popescu and Faussone-Pellegrini (2010). Since then, 368 papers containing the term 'telocyte' have been published, 261 of them in the last five years. These numbers underscore the growing interest in this cell type in the scientific community and the general acceptance of the name telocyte to indicate this interstitial cell. Most of these studies, while confirming the importance of transmission electron microscopy to identify the telocytes with certainty, highlight the variability of their immune phenotypes. This variability was interpreted as due to (i) the ability of the telocytes to adapt to the different sites in which they reside; (ii) the distinct functions they are likely to perform; and (iii) the existence of telocyte subtypes. In the present paper, an overview of the last 10 years of literature on telocytes located in the gut will be attempted, confining the revision to the morphological findings. A distinct chapter will be dedicated to the recently hypothesized role of the telocytes the intestinal mucosa. Through this review, it will be shown that telocytes, despite their variability, are a unique interstitial cell.

Innervation of internal female genital organs in the pig during prenatal development

This study investigated the innervation of internal genital organs in 5-, 7- and 10-week-old female pig foetuses using single and double-labelling immunofluorescence methods. The structure and topography of the organs was examined using a scanning electron microscope (SEM). The investigations revealed differences in the innervation between the three developmental periods. Immunostaining for protein gene product 9.5 (PGP; general neural marker) disclosed solitary nerve fibres in the external part of the gonadal ridge and just outside of the mesenchyme surrounding mesonephric ducts in 5-week-old foetuses. Double-labelling immunohistochemistry revealed that nerve fibres associated with the ridge expressed dopamine β-hydroxylase (DβH; adrenergic marker) or vesicular acetylcholine transporter (VAChT; cholinergic marker). In 7-week-old foetuses, the PGP-positive nerve terminals were absent from the gonad but some of them ran outside and along, and sometimes penetrated into the mesenchyme surrounding the tubal and uterine segments of the paramesonephric ducts and uterovaginal canal. Few axons penetrated into the mesenchyme. DβH-positive fibres were found in single nerve strands or bundles distributed at the edge of the mesenchyme. VAChT-positive nerve terminals formed delicate bundles located at the edge of the mesenchyme, and the single nerves penetrated into the mesenchyme. DβH was also expressed by neurons which formed cell clusters comprising also DβH- or VAChT-positive nerve fibres. In 10-week-old foetuses, PGP-positive nerve fibres were still absent from the ovary but some were distributed in the mesenchyme associated with the uterovaginal canal and uterine and a tubal segment of the paramesonephric ducts, respectively. DβH- or VAChT-positive nerve fibres were distributed at the periphery of the mesenchyme associated with the uterovaginal canal. Some DβH- and many VAChT-positive nerve fibres were evenly distributed throughout the mesenchyme. The clusters of nerve cells comprised DβH-positive perikarya and DβH- or VAChT-positive nerve fibres. The investigations revealed no DβH/VAChT-positive nerve fibres or neurons as well as no nerve structures stained for calcitonin gene-related peptide and/or substance P (sensory markers) associated with the genital organs in the studied prenatal periods.

Preventing and Treating Colic

Colic is a common and distressing functional gastrointestinal disorder during infancy. It is a behavioral phenomenon in infants aged 1-4 months involving prolonged inconsolable crying and agitated status with multifactorial etiology. Colic can be considered as a benign, self-limited process because the baby normally grows and feeds even with transient irritable mood. Nevertheless, infantile colic is a common difficulty causing anxiety during parenthood and a recurrent reason for them to seek medical help, especially if it is the first child. The causes of colic can be classified as non-gastrointestinal or gastrointestinal. The former includes altered feeding techniques, modified child-parent relationship, immaturity of central nervous system, behavioral etiology, and maternal smoking or nicotine replacement therapy. Instead, the latter involves inadequate production of lactase enzyme, cow's milk protein intolerance, alteration of intestinal microbiota, gastrointestinal immaturity, or inflammation which causes intestinal hyperperistalsis due to increase in serotonin secretion and motilin receptor expression.Probiotics may play a crucial part in the manipulation of the microbiota. Probiotic administration is likely to maintain intestinal homeostasis through the modulation of permeability and peristalsis, influencing the gut-brain axis and inhibiting hypersensitivity. This is a decisive field in the development of preventive and therapeutic strategies for infantile colic. However, further studies are needed for each specific formulation in order to better characterize pharmacodynamic and pharmacokinetic properties and to evaluate their application as a possible preventive strategy if administered early during infancy against the later development of pain-related FGIDs.

Abnormal small bowel motility in patients with hereditary transthyretin amyloidosis

BACKGROUND

Gastrointestinal complications are common in hereditary transthyretin amyloid (ATTRm) amyloidosis. The underlying mechanisms have not been fully elucidated, and the patients' small bowel function remains largely unexplored. The aim of the present study was to compare the small bowel motility in ATTRm amyloidosis patients with that in non-amyloidosis patient controls.

METHODS

ATTRm amyloidosis patients undergoing evaluation for liver transplantation were consecutively investigated with 24-hour duodenojejunal manometry (n = 19). The somatostatin analogue octreotide was used to induce fasting motility. Patients with age at onset of ≥50 years were defined as late-onset cases. For each patient, three age- and sex-matched patient controls (n = 57) were selected from the total pool of investigated patients.

KEY RESULTS

Manometry was judged as abnormal in 58% of the patients and in 26% of the patient controls (P = .01). Patients displayed significantly more daytime phase III migrating motor complexes than patient controls (median 4 vs 2, P < .01), and had a higher frequency of low-amplitude complexes (16% vs 4%; however, this difference did not reach statistical significance, P = .10). Furthermore, late-onset patients showed a delay in octreotide response (5.4 vs 3.8 minutes, P < .01), but this was not observed for early-onset patients or within the control group.

CONCLUSIONS AND INFERENCES

Patients with ATTRm amyloidosis displayed abnormalities in their small bowel motility more frequently than non-amyloidosis patient controls, and the manometric pattern was probably best consistent with a combined neuromyopathic disorder. The delayed octreotide response in late-onset patients warrants further investigation.

Development of interstitial cells of Cajal in the human digestive tract as the result of reciprocal induction of mesenchymal and neural crest cells

Neural crest cells (NCC) can migrate into different parts of the body and express their strong inductive potential. In addition, they are multipotent and are able to differentiate into various cell types with diverse functions. In the primitive gut, NCC induce differentiation of muscular structures and interstitial cells of Cajal (ICC), and they themselves differentiate into the elements of the enteric nervous system (ENS), neurons and glial cells. ICC develop by way of mesenchymal cell differentiation in the outer parts of the primitive gut wall around the myenteric plexus (MP) ganglia, with the exception of colon, where they appear simultaneously also at the submucosal border of the circular muscular layer around the submucosal plexus (SMP) ganglia. However, in a complex process of reciprocal induction of NCC and local mesenchyma, c‐kit positive precursors are the first to differentiate, representing probably the common precursors of ICC and smooth muscle cells (SMC). C‐kit positive precursors could represent a key impact factor regarding the final differentiation of NCC into neurons and glial cells with neurons subsequently excreting stem cell factor (SCF) and other signalling molecules. Under the impact of SCF, a portion of c‐kit positive precursors lying immediately around the ganglia differentiate into ICC, while the rest differentiate into SMC.

Abdominal Manual Therapy Repairs Interstitial Cells of Cajal and Increases Colonic c-Kit Expression When Treating Bowel Dysfunction after Spinal Cord Injury

Background

This study aimed to evaluate the therapeutic effects of abdominal manual therapy (AMT) on bowel dysfunction after spinal cord injury (SCI), investigating interstitial cells of Cajal (ICCs) and related c-kit expression.

Methods

Model rats were divided as SCI and SCI with drug treatment (intragastric mosapride), low-intensity (SCI + LMT; 50 g, 50 times/min), and high-intensity AMT (SCI + HMT; 100 g, 150 times/min). After 14 days of treatment, weight, improved Basso-Beattie-Bresnahan (BBB) locomotor score, and intestinal movement were evaluated. Morphological structure of spinal cord and colon tissues were examined. Immunostaining, RT-PCR, and western blot were used to assess c-kit expression.

Results

In SCI rats, AMT could not restore BBB, but it significantly increased weight, shortened time to defecation, increased feces amounts, and improved fecal pellet traits and colon histology. AMT improved the number, distribution, and ultrastructure of colonic ICCs, increasing colonic c-kit mRNA and protein levels. Compared with the SCI + Drug and SCI + LMT groups, the SCI + HMT group showed better therapeutic effect in improving intestinal transmission function and promoting c-kit expression.

Conclusions

AMT is an effective therapy for recovery of intestinal transmission function. It could repair ICCs and increase c-kit expression in colon tissues after SCI, in a frequency-dependent and pressure-dependent manner.

Interstitial cells of Cajal and telocytes in the gut: twins, related or simply neighbor cells?

In the interstitium of the connective tissue several types of cells occur. The fibroblasts, responsible for matrix formation, the mast cells, involved in local response to inflammatory stimuli, resident macrophages, plasma cells, lymphocytes, granulocytes and monocytes, all engaged in immunity responses. Recently, another type of interstitial cell, found in all organs so far examined, has been added to the previous ones, the telocytes (TC). In the gut, in addition to the cells listed above, there are also the interstitial cells of Cajal (ICC), a peculiar type of cell exclusively detected in the alimentary tract with multiple functions including pace-maker activity. The possibility that TC and ICC could correspond to a unique cell type, where the former would represent an ICC variant outside the gut, was initially considered, however, further studies have clearly shown that ICC and TC are two distinct types of cells. In the gut, while the features and the roles of the ICC are established, part of the scientific community is still disputing these 'new' interstitial cells to which several names such as fibroblast-like cells (FLCs), interstitial Cajal-like cells or, most recently, PDGFRα+ cells have been attributed. This review will detail the main features and roles of the TC and ICC with the aim to establish their relationships and hopefully define the identity of the TC in the gut.

Regenerative capacity of the enteric nervous system: is immaturity defining the point of no return?

BACKGROUND

Intestinal obstruction in newborns is associated with intestinal motility disorders after surgery. Alterations in the enteric nervous system (ENS) might cause abnormal peristalsis, which may then result in intestinal motility disorders. We aimed to quantify alterations in the myenteric plexus after a ligation and to test if these alterations were reversible.

METHODS

Small intestines of chicken embryos were ligated in ovo at embryonic day (ED) 11 for either 4 d (ED 11-15) or 8 d (ED 11-19). Both treated groups and control group were sacrificed and intestinal segments examined by means of both light and electron microscopy.

RESULTS

The number of proximal myenteric ganglia increased (ED 19, 30.7 ± 3.16 versus 23.1 ± 2.03; P < 0.001) in the 8-d ligature group but had values similar to the control group in the 4-d ligature group. The size distribution was skewed toward small ganglia in the 8-d ligature group (ED 19, 83.71 ± 11.60% versus 3.88 ± 4.74% in the control group; P < 0.001) but comparable with the control group in the 4-d ligature group. Subcellular alterations in the 4-d ligature group were reversible.

CONCLUSIONS

The pathologic alterations in the ENS were fully reversible in the 4-d ligature group. This reversibility might be linked to the degree of immaturity of the ENS.

Stimulus-induced pacemaker activity in interstitial cells of Cajal associated with the deep muscular plexus of the small intestine

BACKGROUND

The ICC-DMP have been proposed to generate stimulus-dependent pacemaker activity, rhythmic transient depolarizations, that take part in orchestrating segmentation and clustered propulsive motor patterns in the small intestine. However, little is known about the fundamental properties of ICC-DMP.

METHODS

This study was undertaken to increase our understanding of intrinsic properties of the ICC-DMP through calcium imaging and intracellular electrical recordings.

KEY RESULTS

Without stimulation, most ICC-DMP were quiescent. In some preparations ICC-DMP generated rhythmic low-frequency calcium oscillations (<10 cpm) with or without high frequency activity superimposed (>35 cpm). Immunohistochemistry proved the existence of NK1R on the ICC-DMP and close contacts between ICC-DMP and substance P-positive nerves. Substance P (25 nM) induced low-frequency calcium oscillations that were synchronized across the ICC-DMP network. Substance P also induced low frequency rhythmic transient depolarizations (<10cpm) in circular muscle cells close to the ICC-DMP. An intracellular recording from a positively identified ICC-DMP showed rhythmic transient depolarizations with superimposed high frequency activity. To investigate if quiescent ICC-DMP were chronically inhibited by nitrergic activity, nNOS was inhibited, but without effect.

CONCLUSIONS & INFERENCES

Substance P changes non-synchronized high frequency flickering or quiescence in ICC-DMP into strong rhythmic calcium transients that are synchronized within the network; they are associated with rhythmic transient depolarizations within the same frequency range. We hypothesize that Substance P, released from nerves, can evoke rhythmicity in ICC-DMP, thereby providing it with potential pacemaker activity.

Multidirectional and simultaneous evaluation of gastroschisis-related intestinal damage in chick embryos

PURPOSE

In a chick model of gastroschisis, we aimed to investigate the morphological/cellular, molecular, and ultrastructural changes taking place in gastroschisis-related intestinal damage (GRID).

METHODS

13-Day fertilized eggs were divided into two groups.

CONTROL GROUP

chorio-amnio-allontoic membranes opened and abdominal wall exposed. Gastroschisis group: an anterior abdominal wall defect created after opening membranes. Embryos from both groups were surgically removed on post-fertilization day 19. Intestinal samples were obtained for histopathology, immunohistochemistry, molecular biology, and electron microscopy.

RESULTS

The histopathological grade of intestinal damage which primarily involved mucosal structures was significantly higher in the gastroschisis group when compared to the control group (p<0.001). Immunohistochemically, E-cadherin and synaptophysin immunoreactivity in the gastroschisis group was significantly lower than control group (p<0.05 and p<0.01, respectively), whereas there was no significant difference in laminin and type-4 collagen immunoreactivity between the groups (p>0.05). Molecular analyses indicated a significant decrease in NFκB and IκB expression in the gastroschisis group (p<0.05 and p=0.001, respectively). Electron microscopy showed that the gastroschisis group had considerable ultrastructural damage, manifested by apoptosis in all layers.

CONCLUSIONS

GRID affected all layers but was more prominent in mucosa. The damage may depend on E-cadherin and synaptophysin downregulation. Increased apoptotic activity, associated with decreased NFκB and IκB expression, may be an important component of this multifactorial damaging process.

Interstitial cells: regulators of smooth muscle function

Smooth muscles are complex tissues containing a variety of cells in addition to muscle cells. Interstitial cells of mesenchymal origin interact with and form electrical connectivity with smooth muscle cells in many organs, and these cells provide important regulatory functions. For example, in the gastrointestinal tract, interstitial cells of Cajal (ICC) and PDGFRα(+) cells have been described, in detail, and represent distinct classes of cells with unique ultrastructure, molecular phenotypes, and functions. Smooth muscle cells are electrically coupled to ICC and PDGFRα(+) cells, forming an integrated unit called the SIP syncytium. SIP cells express a variety of receptors and ion channels, and conductance changes in any type of SIP cell affect the excitability and responses of the syncytium. SIP cells are known to provide pacemaker activity, propagation pathways for slow waves, transduction of inputs from motor neurons, and mechanosensitivity. Loss of interstitial cells has been associated with motor disorders of the gut. Interstitial cells are also found in a variety of other smooth muscles; however, in most cases, the physiological and pathophysiological roles for these cells have not been clearly defined. This review describes structural, functional, and molecular features of interstitial cells and discusses their contributions in determining the behaviors of smooth muscle tissues.

Is early delivery beneficial in gastroschisis?

PURPOSE

Gastroschisis neonates have delayed time to full enteral feeds (ENT), possibly due to bowel exposure to amniotic fluid. We investigated whether delivery at <37weeks improves neonatal outcomes of gastroschisis and impact of intra/extra-abdominal bowel dilatation (IABD/EABD).

METHODS

A retrospective review of gastroschisis (1992-2012) linked fetal/neonatal data at 2 tertiary referral centers was performed. Primary outcomes were ENT and length of hospital stay (LOS). Data (median [range]) were analyzed using parametric/non-parametric tests, positive/negative predictive values, and regression analysis.

RESULTS

Two hundred forty-six patients were included. Thirty-two were complex (atresia/necrosis/perforation/stenosis). ENT (p<0.0001) and LOS (p<0.0001) were reduced with increasing gestational age. IABD persisted to last scan in 92 patients, 68 (74%) simple (intact/uncompromised bowel), 24 (26%) complex. IABD or EABD diameter in complex patients was not significantly greater than simple gastroschisis. Combined IABD/EABD was present in 22 patients (14 simple, 8 complex). When present at <30weeks, the positive predictive value for complex gastroschisis was 75%. Two patients with necrosis and one atresia had IABD and collapsed extra-abdominal bowel from <30weeks.

CONCLUSION

Early delivery is associated with prolonged ENT/LOS, suggesting elective delivery at <37weeks is not beneficial. Combined IABD/EABD or IABD/collapsed extra-abdominal bowel is suggestive of complex gastroschisis.

Appearance of interstitial cells of Cajal in the human midgut

Several subtypes of the interstitial cells of Cajal (ICC) form networks that play a role in gastrointestinal motor control. ICC express c-kit and depend on signaling via Kit receptors for development and phenotype maintenance. At 7-8 weeks of development, c-kit-immunoreactive (c-kit-IR) cells are present in the human oesophagus, stomach and proximal duodenum wall. In the remaining small and large bowel, c-kit-IR cells appear later. The object of the present study is to determine the timing of the appearance of c-kit-IR ICC in the parts of the digestive tube originating from the midgut (distal duodenum, jejunum, ileum and proximal colon). Specimens were obtained from eight human embryos and 11 fetuses at 7-12 weeks of gestational age. The specimens were exposed to anti-c-kit antibodies to investigate ICC differentiation. The differentiation of enteric neurons and smooth muscle cells was immunohistochemically examined by using anti-PGP9,5 and anti-desmin antibodies, respectively. In the distal duodenum, jejunum and ileum, c-kit-IR cells emerged at week 9 at the level of the myenteric plexus in the form of a thin row of cells encircling the inception of the ganglia. These cells were multipolar or spindle-shaped with two long processes and corresponded to the ICC of the myenteric plexus. In the proximal colon, c-kit-IR cells emerged at week 9-10 in the form of two parallel belts of cells extending at the submucosal plexus and the myenteric plexus levels. We conclude that ICC develop following two different patterns in the human midgut.

Cells derived from the coelomic epithelium contribute to multiple gastrointestinal tissues in mouse embryos

Gut mesodermal tissues originate from the splanchnopleural mesenchyme. However, the embryonic gastrointestinal coelomic epithelium gives rise to mesenchymal cells, whose significance and fate are little known. Our aim was to investigate the contribution of coelomic epithelium-derived cells to the intestinal development. We have used the transgenic mouse model mWt1/IRES/GFP-Cre (Wt1^cre) crossed with the Rosa26R-EYFP reporter mouse. In the gastrointestinal duct Wt1, the Wilms’ tumor suppressor gene, is specific and dynamically expressed in the coelomic epithelium. In the embryos obtained from the crossbreeding, the Wt1-expressing cell lineage produces the yellow fluorescent protein (YFP) allowing for colocalization with differentiation markers through confocal microscopy and flow cytometry. Wt1^cre-YFP cells were very abundant throughout the intestine during midgestation, declining in neonates. Wt1^cre-YFP cells were also transiently observed within the mucosa, being apparently released into the intestinal lumen. YFP was detected in cells contributing to intestinal vascularization (endothelium, pericytes and smooth muscle), visceral musculature (circular, longitudinal and submucosal) as well as in Cajal and Cajal-like interstitial cells. Wt1^cre-YFP mesenchymal cells expressed FGF9, a critical growth factor for intestinal development, as well as PDGFRα, mainly within developing villi. Thus, a cell population derived from the coelomic epithelium incorporates to the gut mesenchyme and contribute to a variety of intestinal tissues, probably playing also a signaling role. Our results support the origin of interstitial cells of Cajal and visceral circular muscle from a common progenitor expressing anoctamin-1 and SMCα-actin. Coelomic-derived cells contribute to the differentiation of at least a part of the interstitial cells of Cajal.

The distribution of HCN2-positive cells in the gastrointestinal tract of mice

HCN2 channels are involved in the spontaneous rhythmic activities of some CNS neurons and act by generating I(f) current. The gastrointestinal (GI) tract is known to be capable of spontaneous rhythmic activity; however, the possible role of HCN2 channels in this organ has not yet been elucidated. This study investigated the distribution of HCN2-positive cells in the mouse GI tract using immunohistochemistry. To identify the nature of these HCN2 cells, anti-ChAT and anti-Kit antibodies were used to co-label neurons and the interstitial cells of Cajal (ICCs), respectively. Additionally, differences in the distribution of HCN2-positive cells within the GI tract were also analyzed. Our results showed that HCN2 channels were mainly located within the myenteric neurons of the enteric nervous system in the GI tract. Double-staining revealed that HCN2-positive neurons were labeled by ChAT, indicating that these HCN2-positive cells are also cholinergic neurons. Although the HCN2-positive cells were not stained by the anti-Kit antibody, their processes were in close proximity to ICCs around the myenteric plexus region. Moreover, several differences in the distribution of HCN2 in the stomach, small intestine and colon were partly consistent with the regional differences in the spontaneous rhythmic activities of these organs. Basing on the role HCN2, we suggested that HCN2 channels facilitate the release of Ach from cholinergic neurons to affect the GI peristalsis by acting on M receptors on the ICCs. However, the HCN2 channels are not directly involved in spontaneous slow-wave initiation by ICCs.

Two patterns of development of interstitial cells of Cajal in the human duodenum

At the end of the embryonic period of human development, c-kit immunoreactive (c-kit IR) cells identifiable as interstitial cells of Cajal (ICC) are present in the oesophagus and stomach wall. In the small and large bowel, c-kit-IR cells appear later (in the small bowel at 9 weeks, and in the colon at 10-12 weeks), also in the MP region. The object of this study was to determine the timing of appearance and distribution of c-kit IR cells in the human embryonic and foetal duodenum. I used immunohistochemistry to examine the embryonic and foetal duodenum for cells expressing CD117 (Kit), expressed by mature ICC and ICC progenitor cells and CD34 to identify presumed ICC progenitors. Enteric plexuses were examined by way of antineuron-specific enolase and the differentiation of smooth muscle cells was studied using antidesmin antibodies. At the end of the embryonic period of development, c-kit IR cells were solely present in the proximal duodenum in the form of a wide belt of densely packed cells around the inception of the myenteric plexus (MP) ganglia. In the distal duodenum, c-kit IR cells emerged at the beginning of the foetal period in the form of thin rows of pleomorphic cells at the level of the MP. From the beginning of the fourth month, the differences in the distribution of ICC in the different portions of the duodenum were established, and this relationship was still present in later developmental stages. In fact, in the proximal duodenum, ICC of the MP (ICC-MP), ICC of the circular muscle (ICC-CM) and ICC of the septa (ICC-SEP) were present, and in the distal duodenum ICC-MP and ICC-SEP only. In conclusion, in the humans there is a difference in the timing and patterns of development of ICC in the proximal duodenum compared to the distal duodenum.

Differentiation of interstitial cells of Cajal in the human distal colon

At the end of the embryonic period of human development, interstitial cells of Cajal (ICC) are present in the esophagus, stomach, and proximal duodenum, around the inception of the myenteric plexus (MP) ganglia. In the small and large bowel, ICC appear later. The object of the present study was to determine the timing of appearance and pattern of distribution of ICC in the human embryonic and fetal distal colon. Human distal colon specimens were obtained from 8 embryos and 14 fetuses without gastrointestinal disorders. The specimens were 7-16 weeks of gestational age. The specimens were exposed to anti-c-kit antibodies to investigate ICC differentiation. Enteric plexuses were immunohistochemically examined using anti-neuron-specific enolase, and the differentiation of smooth muscle cells was studied with anti-desmin antibodies. In the distal colon, ICC emerged at weeks 10-11 of the fetal period in the form of two parallel belts of densely packed cells extending at the submucous plexus (SMP) and the MP level. These cells correspond to ICC of the SMP (ICC-SMP) and ICC of the MP (ICC-MP). The simultaneous appearance of ICC at the SMP and MP level in the distal colon can be explained by the fact that there are differences in the migration of neural crest cells in particular portions of the digestive tube. In conclusion, in humans, there was a difference in the patterns of development of ICC in the distal colon compared to the rest of the gut.

Telocytes

Here, we review the history, morphology, immunohistochemical phenotype, and presumptive roles of a new type of interstitial tissue cells, formerly called interstitial Cajal-like cells (ICLC) and by 2010 named ‘telocytes’ (TC). Many different techniques have been used to characterize TC and provide their unequivocal identification: (i) in vitro, cultures and isolated cells; (ii) in situ, fixed specimens examined by light and fluorescence microscopy, transmission (TEM) and scanning electron microscopy, and electron tomography. TEM allowed sure identification and characterization of the most peculiar feature of TC: the long, thin, and convoluted prolongations named ‘telopodes’. An enormous variety of antibodies have been tested, but presently none are reliable to specifically label TC. TC have a mesenchymal origin and are resident connective tissue (stromal) cells. Possible identification with ‘already identified’ stromal cell types (fibroblasts, fibrocytes, fibroblast-like cells, and mesenchymal stromal cells) is discussed. We conclude that in adulthood, most of the TC have the morphology of fibrocytes. Apparently, immunocytochemistry suggests that a variety of TC populations showing different, likely organ-specific, immunophenotypes might exist. Several roles have been hypothesized for TC: mechanical roles, intercellular signaling, guiding and nursing of immature cells during organogenesis, and being themselves a pool of precursors for many of the mesenchyme-derived cells in adulthood; however, none of these roles have been proven yet. On the basis of the available data, we propose TC may be key players in organ regeneration and repair.

Lactobacillus reuteri accelerates gastric emptying and improves regurgitation in infants

BACKGROUND

Young infants are frequently affected by uncomplicated regurgitation that may persist despite dietetic and conservative interventions. On this basis, we studied the putative effects of probiotics on the frequency of regurgitation and gastric emptying time in infants with functional gastroesophageal reflux (GER).

PATIENTS AND METHODS

Forty-two infants with regurgitation were randomized to assume Lactobacillus reuteri DSM 17938 at a dose of 1 × 10(8) CFU per day and placebo for 30 days. The episodes of regurgitation were recorded by the parents each day. Gastric emptying time was recorded using real-time ultrasound at baseline and at the end of the study. Twenty-one infants without regurgitation were enroled to compare anthropometric and physiological parameters before the intervention diet.

RESULTS

Thirty-four infants completed the study (19 infants receiving probiotics and 15 placebo).At baseline, the whole group of infants was similar to the control group as regards anthropometric and physiological data. The median fasting antral area was significantly reduced, (P = 0·01) the delta in gastric emptying rate was significantly increased (P = 0·01) and the median episodes per day of regurgitation was reduced (, P < 0·001) in the probiotic group compared to the placebo group. In the whole group, the frequency of regurgitation and the basal antral area showed a positive correlation (r = 0·53, P = 0·004).

CONCLUSIONS

In infants with functional GER, L. reuteri DSM 17938 reduce gastric distension and accelerate gastric emptying. In addition, this probiotic strain seems to diminish the frequency of regurgitation.

Reduction of interstitial cells of Cajal in esophageal atresia

OBJECTIVES

Postrepair esophageal dysmotility and gastroesophageal reflux are well-known consequences in patients with congenital esophageal atresia (EA) with or without distal tracheoesophageal fistula (TEF). The interstitial cells of Cajal (ICC), considered the intestinal pacemaker, are altered in congenital diseases with abnormal peristalsis, but no data are available for EA. Therefore, presence and maturation of ICC was verified in EA-TEF newborns.

PATIENTS AND METHODS

Fifteen full-term neonates underwent repair of EA-TEF. Control specimens were from 10 newborns who died of nonesophageal diseases. Specimens from upper pouch, fistula, proximal, and distal esophagus were processed for hematoxylin and eosin, c-kit immunohistochemistry for ICC identification, and transmission electron microscopy. Frequency of c-kit-positive cells was evaluated in 20 fields per slide using a visual score (absent, very low, low, medium, high, very high). Morphocytometry and statistical analysis were also performed.

RESULTS

In the proximal normal esophagus, ICC frequency was very high (3 cases), high (5), and medium (2); distally, it was high (4) and medium (6). In EA-TEF upper pouch, it was high (2) and medium (13); in the fistula, it was medium (5), low (6), very low (3), and absent (1). Morphocytometry confirmed these results. Comparison between pouch and fistula versus proximal and lower esophagus, respectively, showed statistically significant differences. Transmission electron microscopy demonstrated ICC immaturity in EA-TEF.

CONCLUSIONS

The significant lower ICC density in EA-TEF is in favor for the pathogenesis of esophageal dysmotility frequently observed in such patients.

Development of c-kit immunopositive interstitial cells of Cajal in the human stomach

Interstitial cells of Cajal (ICC) include several types of specialized cells within the musculature of the gastrointestinal tract (GIT). Some types of ICC act as pacemakers in the GIT musculature, whereas others are implicated in the modulation of enteric neurotransmission. Kit immunohistochemistry reliably identifies the location of these cells and provides information on changes in ICC distribution and density. Human stomach specimens were obtained from 7 embryos and 28 foetuses without gastrointestinal disorders. The specimens were 7-27 weeks of gestational age, and both sexes are represented in the sample. The specimens were exposed to anti-c-kit antibodies to investigate ICC differentiation. Enteric plexuses were immunohistochemically examined by using anti-neuron specific enolase and the differentiation of smooth muscle cells (SMC) was studied with anti-alpha smooth muscle actin and anti-desmin antibodies. By week 7, c-kit-immunopositive precursors formed a layer in the outer stomach wall around myenteric plexus elements. Between 9 and 11 weeks some of these precursors differentiated into ICC. ICC at the myenteric plexus level differentiated first, followed by those within the muscle layer: between SMC, at the circular and longitudinal layers, and within connective tissue septa enveloping muscle bundles. In the fourth month, all subtypes of c-kit-immunoreactivity ICC which are necessary for the generation of slow waves and their transfer to SMC have been developed. These results may help elucidate the origin of ICC and the aetiology and pathogenesis of stomach motility disorders in neonates and young children that are associated with absence or decreased number of these cells.

Tonic inhibition of human small intestinal motility by nitric oxide in children but not in adults

BACKGROUND

Gastrointestinal motility is dependent on neural influences that largely involve the enteric nervous system (ENS). The main motor patterns that occur in the fasted and fed state are noticeably different in children compared with adults. Although the development of the ENS continues after birth, there is no data on the contractile activity of segments of small intestine from young children. This study was designed to provide data on the development of muscle control by the human ENS with particular attention to acetylcholine (ACh) and nitric oxide (NO) as the primary neurotransmitters of enteric motor neurons, respectively.

METHODS

Small intestinal specimens were obtained from 11 children and six adults undergoing surgery for various diseases. The mechanical activity of the circular muscle was recorded in vitro. The effects of N(ω)-nitro-L-arginine methyl ester hydrochloride, an inhibitor of NO synthesis, and of atropine, an antagonist of muscarinic receptors, were tested on the spontaneous motility and responses to nerve stimulation.

KEY RESULTS

Spontaneous motility was observed in all preparations. Responses to nerve stimulation were identical in child and adult. No tonic cholinergic excitation of small intestinal motility was observed either in child or in adult. Inhibition of NO synthesis induced a major disinhibition of motility in child but not in adult.

CONCLUSIONS & INFERENCES

Spontaneous intestinal motility and cholinergic and nitrergic neurotransmission are present from birth. NO provides a tonic inhibition of intestinal motility only in child. Our study indicates that NO may be a major player in shaping the ontogenic development of intestinal motility in human.

C-kit-immunopositive interstitial cells of Cajal in human embryonal and fetal oesophagus

Interstitial cells of Cajal (ICC) are morphologically and functionally intercalated between the elements of the enteric nervous system and the smooth muscle cells (SMCs) in the musculature of the digestive tract. Kit immunohistochemistry reliably identifies the location of these cells and provides information on changes in ICC distribution and density. Human oesophagus specimens (7 embryos, 23 fetuses at 7-27 weeks gestational age; both sexes) were exposed to Kit antibodies to determine ICC differentiation. Enteric plexuses were examined immunohistochemically by using anti-neuron-specific enolase, whereas the differentiation of SMCs was studied with antibodies against alpha-smooth-muscle actin and desmin. By week 7, c-kit-immunopositive cells were present along the entire oesophagus in the form of an uninterrupted layer around the myenteric plexus (MP) elements. From the beginning of the 3rd month, the number of ICC progressively decreased around the MP ganglia but increased within the muscle layers. Concomitantly, differences in the number and distribution of ICC were established in the various portions of the oesophagus: specifically, ICC were abundant in the lower portion, less numerous in the middle region and rare in the upper part. By the 5th month of development, the relationship as found in later developmental stages had been established: C-kit IR ICC were present within the circular muscle layer, within the longitudinal layer and in the connective septa surrounding the muscle bundles but were completely missing around the MP ganglia.

Interstitial cells of Cajal, macrophages and mast cells in the gut musculature: morphology, distribution, spatial and possible functional interactions

Interstitial cells of Cajal (ICC) are recognized as pacemaker cells for gastrointestinal movement and are suggested to be mediators of neuromuscular transmission. Intestinal motility disturbances are often associated with a reduced number of ICC and/or ultrastructural damage, sometimes associated with immune cells. Macrophages and mast cells in the intestinal muscularis externa of rodents can be found in close spatial contact with ICC. Macrophages are a constant and regularly distributed cell population in the serosa and at the level of Auerbach's plexus (AP). In human colon, ICC are in close contact with macrophages at the level of AP, suggesting functional interaction. It has therefore been proposed that ICC and macrophages interact. Macrophages and mast cells are considered to play important roles in the innate immune defence by producing pro-inflammatory mediators during classical activation, which may in itself result in damage to the tissue. They also take part in alternative activation which is associated with anti-inflammatory mediators, tissue remodelling and homeostasis, cancer, helminth infections and immunophenotype switch. ICC become damaged under various circumstances - surgical resection, possibly post-operative ileus in rodents - where innate activation takes place, and in helminth infections - where alternative activation takes place. During alternative activation the muscularis macrophage can switch phenotype resulting in up-regulation of F4/80 and the mannose receptor. In more chronic conditions such as Crohn's disease and achalasia, ICC and mast cells develop close spatial contacts and piecemeal degranulation is possibly triggered.

Pilot study for in vivo cellular imaging of the muscularis propria and ex vivo molecular imaging of myenteric neurons (with video)

BACKGROUND

It is challenging to optimally sample the muscularis propria endoscopically for the diagnosis of muscle layer diseases, especially for motility disorders resulting from neuroenteric dysfunction.

OBJECTIVES

Ultramagnification in vivo imaging of the muscularis mucosa and ex vivo identification of myenteric neuronal elements by confocal microscopy.

DESIGN

Ex vivo and in vivo porcine animal studies.

SETTING

Short-term study in an animal laboratory.

INTERVENTIONS

The muscularis propria in the stomach and esophagus was accessed by resecting the mucosal layer with endoscopic submucosal dissection or cap EMR techniques or by creating a submucosal space by the submucosal endoscopy with mucosal flap technique. The muscularis propria was stained with Nissl stains and 2 types of neuronal molecular stains. The muscular layer was imaged with the endocytoscope in vivo. The muscularis stained with molecular-based stains was also evaluated with a confocal microscope.

RESULTS

Cellular microstructures resembling spindle-shaped smooth muscle cells were visualized by endocytoscopy in vivo. Confocal endoscopic microscopy demonstrated that in vivo topical application of neuronal molecular stains successfully stained the muscularis and specifically highlighted neuron-like cells.

LIMITATION

Animal model pilot study.

CONCLUSIONS

In vivo endoscopic histologic evaluation of the muscularis propria is technically feasible and easy. Minimally invasive advanced endoscopic imaging may be useful for the diagnosis and study of neuroenteric disorders at the level of the muscularis propria, avoiding surgical full-thickness tissue sampling.

Histochemical and ultrastructural characteristics of an interstitial cell type different from ICC and resident in the muscle coat of human gut

CD117 (or c-kit) is expressed by the interstitial cells of Cajal (ICC), which are located within the gastrointestinal (GI) muscle coat and directly involved in its motility. CD34 is expressed by several cell types some of which have features and location resembling the ICC; however, a sure identification of these cells is still lacking. In order to establish whether the CD34-positive cells of the human GI tract are to be considered as ICC subpopulation or a novel independent cell type, and to hypothesize their nature and role, we verified CD34 and CD117 receptor expression under light and fluorescence microscope and performed a routine and a CD34-immuno-electron microscopy. CD34-positive cells were seen in the entire human GI tract. In the muscularis propria, shared morphologies similar to the c-kit-positive cells, in the submucosa, resembled fibroblasts. Their ultrastructure resembled that of the fibrocytes/fibroblasts and of the interstitial Cajal-like cells (ICLC). Double labelling and immunoelectro-microscopy demonstrated that they are unequivocally different to the ICC and, due to the similarities with the ICLC, we identified them as ICLC. The novelty of these results is that two types of interstitial cells are present in the GI muscle coat of humans: the ICC and the ICLC. We hypothesize a mechanical role for the septal ICLC, those at the myenteric plexus level and those bordering the muscle layers; a helping role in neurotransmission is proposed for the ICLC intercalated with the intramuscular ICC, possibly in spreading the slow waves generated by the ICC. Furthermore, the possibility that the ICLC represent the adult mesenchymal stromal cells able to guarantee the ICC renewal deserves to be considered.

Delayed development of interstitial cells of Cajal in the ileum of a human case of gastroschisis

The Interstitial Cells of Cajal (ICC) are responsible for rhythmic electrical activity. A paralytic ileus is present in gastroschisis (GS), a malformation due to a defective closure of the abdominal wall through which part of the intestine herniates during pregnancy. In experimental GS, ICC morphological immaturity was shown in the rat foetus at-term but it could not be demonstrated whether differentiation is accomplished post-natally. For this purpose we morphologically investigated ICC, as well as enteric neurons and smooth muscle cells, in a case of human GS at birth and 1 month later when peristaltic activity had initiated. A 36 weeks gestation female was born by c/section with prenatal diagnosis of GS and possible volvulus of the herniated intestine. At birth, the necrotic intestine was resected and both ileostomy and colostomy were performed. The intestine continuity was restored after 4 weeks. Intestinal specimens, taken during both operations at the level of the proximal stoma, were immunostained with c-kit, neuron-specific-enolase and alpha-smooth-muscle-actin antibodies and some processed for electron microscopy. ICC were present at the myenteric plexus only. At birth, these cells were rare and ultrastructurally immature; 1 month later, when partial enteral feeding was tolerated, they formed rows or groups and many of them were ultrastructurally differentiated. Neurons and smooth muscle cells, immature at birth, had developed after 1 month. Therefore, ICC differentiation, as well as that of neurons and smooth muscle cells, is delayed at birth and this might explain the paralytic ileus in GS. One month later, differentiation quickly proceeded at all cellular levels paralleling the increasing tolerance of enteral nutrition.