vasoactive-intestinal-peptide and Megacolon

Megacolon, the irreversible dilation of a colonic segment, is a structural sign associated with various gastrointestinal disorders. In its hereditary, secondary form (e.g. in Hirschsprung's disease), dilation occurs in an originally healthy colonic segment due to an anally located, aganglionic zone. In contrast, in chronic Chagas' disease, the dilated segment itself displays pathohistological changes, and the earliest and most prominent being found was massive loss of myenteric neurons. This neuron loss was partial and selective, i.e. some neurons containing neuronal nitric oxide synthase and/or vasoactive intestinal peptide (VIP) were spared from neuron death. This disproportionate survival of inhibitory neurons, however, did not completely correlate with the calibre change along the surgically removed, megacolonic segments. A better correlation was observed as to potentially contractile muscle tissue elements and the interstitial cells of Cajal. Therefore, the decreased densities of α-smooth muscle actin- and c-kit-immunoreactive profiles were estimated along resected megacolonic segments. Their lowest values were observed in the megacolonic zones itself, whereas less pronounced decreases were found in the non-dilated, transitional zones (oral and anal to dilation). In contrast to the myenteric plexus, the submucosal plexus displayed only a moderate neuron loss. Neurons co-immunoreactive for VIP and calretinin survived disproportionately. As a consequence, these neurons may have contributed to maintain the epithelial barrier and allowed the chagasic patients to survive for decades, despite their severe disturbance of colonic motility. Due to its neuroprotective and neuroeffectory functions, VIP may play a key role in the development and duration of chagasic megacolon.

Topics: Animals; Chagas Disease; Humans; Megacolon; Neurons; Nitric Oxide Synthase Type I; Vasoactive Intestinal Peptide

Chagas' disease is one of the most serious parasitic diseases of Latin America, with a social and economic impact far outweighing the combined effects of other parasitic diseases such as malaria, leishmaniasis and schistosomiasis. In the chronic phase of this disease, the destruction of enteric nervous system (ENS) components leads to megacolon development. Previous data presented that the regeneration tax in the ENS neurons is augmented in chagasic patients. Although, there are several neuronal types with different functions in the intestine a detailed study about the regeneration of every neuronal type was never performed before. Therefore, the aim of this study was to evaluate the regeneration tax of every neuronal cell type in the ENS from chagasic patients with megacolon and non-infected individuals. A neuronal regeneration marker (GAP-43) was used in combination with a pan-neuronal marker (Peripherin) and several neuropeptides markers (cChat, Substance P, NPY, VIP and NOS), and it was considered as positive just with the combination of these markers. Our results demonstrated that the regeneration levels of cChat, Substance P, and NPY were similar in chagasic patients and non-infected individuals. However, levels of VIP and NOS neuropeptides were increased in chagasic patients when compared with non-infected individuals. We believe that the augment in the regeneration occur due to an increased destruction of selective neuronal types. These results corroborates with previous studies that pointed out to selective destruction of VIP and NOS neurons in chagasic patients.

Topics: Adult; Aged; Chagas Disease; Enteric Nervous System; Female; Ganglia, Autonomic; GAP-43 Protein; Humans; Male; Megacolon; Middle Aged; Neurons; Nitric Oxide Synthase; Regeneration; Vasoactive Intestinal Peptide

Chronic Chagas' disease is frequently characterized by massive myenteric neuron loss resulting in megacolon with severely and irreversibly disturbed motility. Here, we focused on two submucosal neuron populations, immunoreactive for calretinin (CALR) or somatostatin (SOM), and their respective mucosal nerve fibres in chagasic megacolon. Surgically removed megacolonic segments of seven chagasic patients were compared with seven age- and region-matched non-chagasic control segments. Evaluation included immunohistochemical triple-staining of cryosections for CALR, SOM and peripherin or for CALR and vasoactive intestinal peptide (VIP) and of submucosal whole-mounts for CALR, SOM and the pan-neuronal marker anti-HuC/D. Submucosal neuron counts in chagasic tissue revealed neuron numbers reduced to 51.2 % of control values. In cryosections, nerve fibre area measurements revealed 8.6 % nerve fibre per mucosal area in control segments, but this value decreased to 1.5 % in megacolonic segments. In both evaluations, a disproportionate decrease of SOM-reactive nerve elements was observed. The proportions of SOM-positive neurons related to the total neuron number declined to 2 % (control 10 %) and the proportion of SOM-reactive mucosal nerve fibres related to the whole mucosal area to 0.014 % (control 1.8 %)in chagasic tissue. The second set of cryosections revealed extensive colocalization of CALR with VIP in both surviving submucosal perikarya and mucosal nerve fibres. We suggest that VIP, a neuroprotective and neuroeffectory peptide typically contained in submucosal neurons, allows both the VIP-containing neurons to endure and the patients to survive by maintaining their mucosal barrier, despite the almost complete loss of colonic motility for decades.

Topics: Aged; Animals; Calbindin 2; Chagas Disease; Female; Humans; Immunohistochemistry; Intermediate Filament Proteins; Intestinal Mucosa; Male; Megacolon; Membrane Glycoproteins; Middle Aged; Nerve Fibers; Nerve Tissue Proteins; Neurons; Peripherins; S100 Calcium Binding Protein G; Somatostatin; Survival Analysis; Vasoactive Intestinal Peptide

Megacolon, chronic dilation of a colonic segment, is a frequent sign of Chagas disease. It is accompanied by an extensive neuron loss which, as shown recently, results in a partial, selective survival of nitrergic myenteric neurons. Here, we focused on the balance of intramuscular excitatory (choline acetyltransferase [ChAT]-immunoreactive) and inhibitory (neuronal nitric oxide synthase [NOS]- as well as vasoactive intestinal peptide [VIP]-immunoreactive) nerve fibres.. From surgically removed megacolonic segments of seven patients, three sets of cryosections (from non-dilated oral, megacolonic and non-dilated anal parts) were immunhistochemically triple-stained for ChAT, NOS and VIP. Separate area measurements of nerve profiles within the circular and longitudinal muscle layers, respectively, were compared with those of seven non-chagasic control patients. Additionally, wholemounts from the same regions were stained for NOS, VIP and neurofilaments (NF).. The intramuscular nerve fibre density was significantly reduced in all three chagasic segments. The proportions of inhibitory (NOS only, VIP only, or NOS/VIP-coimmunoreactive) intramuscular nerves were 68 %/58 % (circular/longitudinal muscle, respectively) in the controls and increased to 75 %/69 % (oral parts), 84 %/76 % (megacolonic) and 87 %/94 % (anal) in chagasic specimens. In the myenteric plexus, NF-positive neurons co-staining for NOS and VIP also increased proportionally. The almost complete lack of dendritic structures in ganglia of chagasic specimens hampered morphological identification.. We suggest that preponderance of inhibitory, intramuscular nerve fibres may be one factor explaining the chronic dilation. Since the nerve fibre imbalance is most pronounced in the anal, non-dilated segment, other components of the motor apparatus (musculature, interstitial cells, submucosal neurons) have to be considered.

Topics: Aged; Chagas Disease; Choline O-Acetyltransferase; Female; Humans; Male; Megacolon; Middle Aged; Muscles; Myenteric Plexus; Nerve Fibers; Neural Inhibition; Neurons; Nitric Oxide Synthase Type I; Vasoactive Intestinal Peptide

We reported decreased vasoactive intestinal peptide levels in acquired megacolon. The origin of altered neuropeptide levels is unknown, but recent work suggested that tissue antioxidants may function as neuroprotectants. Our hypothesis was that altered levels of inhibitory neurotransmitters in human colon are associated with depletion of the tripeptide thiol, glutathione. Normal colon samples (N = 10; from patients 41-80 years old) and acquired megacolon samples (N = 10; from patients 31-98 years old) were obtained at surgery. Vasoactive intestinal peptide levels were decreased in muscularis externa from acquired megacolon (P = 0.01), while there was a modest increase in NADPH diaphorase activity in muscularis externa from megacolon (P = 0.10). Glutathione in acquired megacolon was detectable in muscularis externa from only five specimens (P < 0.05), but was not significantly different (P > 0.05) in the mucosal-submucosal layer. The results supported the presence of vasoactive intestinal peptide and NADPH diaphorase in distinct subpopulations of nerves in human colon. The results also supported the hypothesis that glutathione functions as a neuroprotectant in a subset of patients with acquired megacolon.

Topics: Adult; Aged; Aged, 80 and over; Colon; Glutathione; Humans; Intestinal Mucosa; Megacolon; Middle Aged; Muscle, Smooth; NADPH Dehydrogenase; Radioimmunoassay; Vasoactive Intestinal Peptide

We have studied the resection specimens from 5 patients with idiopathic megarectum and megacolon and 10 control subjects with non-obstructing colonic cancer. Histological staining with haematoxylin and eosin, and immunocytochemical staining for protein gene product 9.5 (PGP9.5), S100 protein, vasoactive intestinal polypeptide (VIP) and calcitonin gene-related peptide (CGRP), and histochemical localization of NADPH diaphorase was performed. The amount of VIP and CGRP present in samples was measured using an enzyme-linked immunosorbent assay. Patients with idiopathic megarectum and megacolon showed hypertrophy of the muscularis mucosae and muscularis externa. The architecture of the innervation as assessed by immunoreactivity for PGP9.5 and S100 protein appeared normal. There was a decrease in the density of innervation of the longitudinal muscle in rectal tissue from patients with idiopathic megarectum, with fewer VIP- and NADPH-diaphorase-containing nerves. In the muscularis mucosae and lamina propria of the rectal samples of patients with idiopathic megarectum, VIP immunoreactivity was higher and more NADPH-diaphorase-containing nerves were seen. CGRP-immunoreactive nerve fibres were only seen in the myenteric plexus. No CGRP-immunoreactive cell bodies were seen. In summary, there is an increase in VIP and nitric oxide containing fibres in the muscularis mucosae and lamina propria and a decrease in the longitudinal muscle in rectal tissue of patients with idiopathic megarectum. Both are NANC (nonadrenergic noncholinergic) inhibitory transmitters in the gut and the possible relationship of the changes in their density with gut function is discussed.

Topics: Adolescent; Adult; Calcitonin Gene-Related Peptide; Colonic Neoplasms; Female; Humans; Immunohistochemistry; Intestine, Large; Male; Megacolon; NADPH Dehydrogenase; Nerve Tissue Proteins; Rectal Diseases; S100 Proteins; Thiolester Hydrolases; Ubiquitin Thiolesterase; Vasoactive Intestinal Peptide

Based upon previous morphologic studies, we hypothesized that the development of acquired megacolon was associated with abnormalities of enteric neurotransmitter concentrations and enzymatic activities. Specimens were obtained at surgery from patients with normal descending-sigmoid colon (n = 13) and patients with sigmoid megacolon (n = 6; defined by radiologic measurement). Radioimmunoassays were used to measure the non-adrenergic, non-cholinergic inhibitory neuropeptide, vasoactive intestinal peptide, and the non-adrenergic, non-cholinergic excitatory neuropeptide, substance P, while spectrophotometric assays were used to quantitate acetylcholinesterase activity and choline acetyltransferase activity. There were significantly decreased concentrations of vasoactive intestinal peptide and decreased acetylcholinesterase activity in muscularis externa from patients with acquired megacolon. In megacolon, vasoactive intestinal peptide-containing nerve fibers appeared to be diminished in circular and longitudinal smooth muscle, and immunostaining of nerve cell bodies in the plexus submucosus externus appeared diminished. These results suggest the hypothesis that production of vasoactive intestinal peptide is altered allowing secondary colonic hypertrophy to develop from prolonged cholinergic nerve-mediated contractions of circular smooth muscle. As a corollary to this hypothesis, colonic dilatation might result from prolonged contraction of longitudinal smooth muscle.

Topics: Acetylcholinesterase; Adult; Aged; Choline O-Acetyltransferase; Colon; Female; Histocytochemistry; Humans; Immunohistochemistry; Male; Megacolon; Middle Aged; Radioimmunoassay; Spectrophotometry; Substance P; Vasoactive Intestinal Peptide

Topics: Colon, Sigmoid; Humans; Megacolon; Peristalsis; Reflex; Substance P; Vasoactive Intestinal Peptide

A 32-yr-old man with myotonic dystrophy had a left hemicolectomy performed because of a megacolon. The colonic mucosa, smooth muscle, and connective tissue appeared normal by hematoxylin and eosin and trichrome stains and transmission electron microscopy. In contrast, the myenteric plexus had markedly fewer neurons than normal on the hematoxylin and eosin stains. Silver staining of the plexus revealed degeneration and decreased numbers of argyrophilic neurons, which were smaller and had fewer processes and a more uneven staining quality than controls. Many axons were fragmented, and increased numbers of glial cell nuclei were present in the plexus. Degenerative changes in the neurons were present in a patchy distribution on transmission electron microscopy. Immunohistochemistry revealed a decrease of the substance P- and enkephalin-immunoreactive fibers in the muscularis externa. This suggests that colonic motor dysfunction associated with myotonic dystrophy may be caused by a visceral neuropathy that involves the substance P- and enkephalin-immunoreactive fibers of the smooth muscle.

Topics: Adult; Colon; Enkephalins; Histocytochemistry; Humans; Male; Megacolon; Myenteric Plexus; Myotonic Dystrophy; Nerve Degeneration; Nerve Fibers; Neuropeptide Y; Radiography; Substance P; Vasoactive Intestinal Peptide

Studies were made of the distribution of gut hormones and neuropeptides in the gastrointestinal tract of mice with hereditary aganglionic colon (s1/s1) and their normal littermates. Antisera to substance P, vasoactive intestinal polypeptide, and enkephalins demonstrated markedly diminished numbers of immunofluorescent nerve fibers in the aganglionic segment of colon; in contrast, in proximal colon and small intestine the distribution of peptidergic nerve fibers was essentially normal. Mucosal endocrine cells were demonstrated in the colon by antisera to substance P, somatostatin, glucagon, and cholecystokinin; in each case there were similar numbers of cells in s1/s1 and normal mice. Radioimmunoassays for vasoactive intestinal polypeptide and bombesin showed diminished concentrations of immunoreactive material in the aganglionic segment of colon of 16-17-day-old animals. However, assays for CCK--which is predominantly located in endocrine cells--showed similar concentrations of immunoreactive material throughout the gut of s1/s1 and normal mice. It was of interest that the concentrations of immunoreactive substance P were lower than normal not only in the aganglionic segment of colon, but also in proximal colon and distal small intestine, and that at all ages the development of substance P in the intestine was delayed in the s1/s1 mice. The results are consistent with the idea that the constriction of the aganglionic segment of colon develops as a consequence of lack of intrinsic inhibitory neurons, possibly those containing vasoactive intestinal polypeptide. The presence of an aganglionic segment is attributable to delayed migration of the neuroblasts from the neural crest. Thus the findings of normal populations of gut endocrine cells in the aganglionic segment is further support for the view that the embryologic origin of gut endocrine cells is different to that of gut neurons.

Topics: Animals; Bombesin; Cholecystokinin; Colon; Endocrine Glands; Genes, Lethal; Genes, Recessive; Megacolon; Mice; Mice, Neurologic Mutants; Nerve Fibers; Neurons; Radioimmunoassay; Substance P; Vasoactive Intestinal Peptide

The colonic tissue content of immunoreactive vasoactive intestinal peptide was measured in four children with histologically proven Hirschsprung's disease. The concentration of vasoactive intestinal peptide was lower in the aganglionic bowel than in nearby normal bowel. Similar results have been described for another gastrointestinal peptide: substance P. Abnormalities of peptidergic control may contribute to the motility disorder of congenital aganglionic colon.

Topics: Child; Colon; Ganglia, Autonomic; Gastrointestinal Hormones; Gastrointestinal Motility; Humans; Megacolon; Substance P; Vasoactive Intestinal Peptide

We describe here a depletion of peptide containing nerves and cells in Hirschsprung's disease, in comparison with specimens of bowel taken from age-matched neonates with no evidence of chronic constipation. VIP content in the diseased specimens was reduced by almost 80%, from 110/+-10.6 (mean +/- SEM) pmol VIP/g wet weight of tissue in controls to 23.8 +/- 3.5 pmol/g in the mid-portion of the diseased specimens. In addition, the numbers of enteroglucagon and somatostatin cells in the mucosa were significantly reduced in the aganglionic portions. Enteroglucagon cells were reduced from 55 +/- 7 in controls to 27 +/- 2 in proximal portions rising to 44 +/- 3 and 49 +/- 4 cells/mm2 in middle and distal areas. Somatostatin cell numbers also fell, from 5.5 +/- 1.9 to 1.8 +/- 0.8, 2.5 +/- 0.7 and 3.8 +/- 0.9 cells/mm2 in similar areas. Further investigation of the abnormalities of the diffuse neuroendocrine system in Hirschsprung's disease may help in understanding the nature of this condition and provide additional information on the role of these peptides in the control of gut function.

Topics: Bombesin; Child, Preschool; Colon; Enkephalin, Methionine; Enkephalins; Fluorescent Antibody Technique; Glucagon-Like Peptides; Humans; Infant; Megacolon; Neurotensin; Peptides; Radioimmunoassay; Somatostatin; Substance P; Vasoactive Intestinal Peptide

Topics: Child, Preschool; Colon; Colonic Neoplasms; Ganglioneuroma; Gastrointestinal Hormones; Gastrointestinal Motility; Humans; Infant; Infant, Newborn; Intestinal Obstruction; Megacolon; Vasoactive Intestinal Peptide

Topics: APUD Cells; Autonomic Nervous System; Bombesin; Brain; Chagas Disease; Cholecystokinin; Crohn Disease; Endocrine Glands; Endorphins; Gastrointestinal Hormones; Humans; Immunochemistry; Megacolon; Neurotensin; Neurotransmitter Agents; Peptides; Somatostatin; Substance P; Vasoactive Intestinal Peptide

Topics: APUD Cells; Autonomic Nervous System; Bombesin; Brain; Chagas Disease; Cholecystokinin; Endorphins; Enkephalins; Fixatives; Gastrointestinal Hormones; Humans; Immunochemistry; Immunoenzyme Techniques; Intestines; Megacolon; Neurotensin; Peptides; Radioimmunoassay; Somatostatin; Substance P; Vasoactive Intestinal Peptide

Topics: Gastrointestinal Hormones; Humans; Megacolon; Tissue Distribution; Vasoactive Intestinal Peptide