vasoactive-intestinal-peptide and Chagas-Disease

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

Vasoactive intestinal peptide (VIP) has gained great prominence because of its therapeutic potential, which is ascribed to its ability to regulate innate immunity, inhibit antigen-specific Th1 cell responses, and generate T regulatory cells. Additionally, VIP may act as a natural antimicrobial peptide, killing bacteria, fungi, and infective forms of Trypanosoma brucei. Despite the possible relevance of VIP during the course of Chagas disease, studies regarding this in human and experimental Trypanosoma cruzi infections remain poorly characterized. In this work, we evaluated the effects of VIP on systemic and cardiac immune responses during experimental acute infection. C57BL/6 mice were infected with 5000 trypomastigotes of the VL-10 strain of T. cruzi and treated with intraperitoneal VIP injection every other day for one month. After 30 days, we observed no reduction in parasitemia levels. However, we observed a reduction in serum levels of IFN-gamma and IL-2 and an increase in that of IL-4. These data suggest that VIP treatment modified immune responses to favor the Th2 response, which had no impact on parasitemia levels although the serum level of IFN-gamma was reduced. However, this change in immune balance reduced heart damage, as noted by the smaller cardiac volume and the moderate inflammatory infiltrate observed in VIP-treated mice. Our results indicate that VIP treatment reduced the inflammatory response at the cardiac site of mice that were experimentally infected with T. cruzi. These data suggest a protective role for VIP in the heart of infected mice.

Topics: Animals; Anti-Inflammatory Agents; Chagas Cardiomyopathy; Chagas Disease; Chemokines; Cytokines; Female; Mice; Mice, Inbred C57BL; Myocardium; Neuroprotective Agents; Parasitemia; Vasoactive Intestinal Peptide

Megaesophagus is one of the major causes of morbidity in chronic Chagas disease, and extensive denervation, associated with an inflammatory process, is recognized as the key factor for alterations in motility and disease development. Here, we analyzed esophagus samples from necropsied, infected individuals--6 cases with megaesophagus and 6 cases without megaesophagus--for the relative areas of expression of 2 neuromediators, substance P and vasoactive intestinal peptide, which are known to activate or inhibit, respectively, local immune cells. Samples from 6 noninfected individuals were used as controls. Esophageal sections were immunohistochemically stained for protein gene product 9.5, vasoactive intestinal peptide, and substance P, and the relative areas of expression of the latter 2 were calculated. Morphometric analyses revealed increased substance P and decreased vasoactive intestinal peptide relative areas in esophageal sections from patients with megaesophagus. Furthermore, in the group of patients without megaesophagus, the loss of vasoactive intestinal peptide positively correlated with the denervation process. We suggest that an imbalance between vasoactive intestinal peptide and substance P production results in the reestablishment and maintenance of the inflammatory process, leading to denervation and, consequently, promoting the development of megaesophagus.

Topics: Adult; Aged; Aged, 80 and over; Chagas Disease; Esophageal Achalasia; Esophagus; Female; Humans; Immunohistochemistry; Male; Middle Aged; Myenteric Plexus; Neurons; Substance P; Trypanosoma cruzi; 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

The distribution of a tachykinin (substance P) and vasoactive intestinal peptide (VIP) and the number and morphology of the large granular vesicles (LGV) in the myenteric plexus of the colons of mice were investigated. Six of the 12 young, male, Swiss mice studied had been inoculated with the Y strain of Trypanosoma cruzi 2 months previously whereas the others were uninfected controls. Substance P (SP) and VIP were localized by light microscopy, using an immunohistochemical method, and LGV were counted in sections studied by electron microscopy. There were far fewer LGV and less intensely staining varicose VIP- and SP-positive nerve fibres in the infected mice than in the controls. Denervation of the myenteric plexus may decrease the content of tachykinins (TK) and VIP in animals infected with T. cruzi. Such reduction in TK and VIP activity could be related to the disturbances in intestinal motility observed in the chronic phase of Chagas disease.

Topics: Animals; Chagas Disease; Chronic Disease; Colon; Immunohistochemistry; Male; Mice; Microscopy, Electron; Myenteric Plexus; Neurons; Substance P; Vacuoles; Vasoactive Intestinal Peptide

The neural and hormonal peptide content of rectal biopsy specimens from 10 patients with chronic autonomic failure, 10 patients with chronic gastrointestinal Chagas' disease, and 13 controls was studied with radioimmunoassay and immunocytochemistry. In the patients with Chagas' disease the mean concentrations of rectal vasoactive intestinal polypeptide, enteroglucagon, substance P, and somatostatin were all less than half of those in controls and in patients with chronic autonomic failure. Immunocytochemistry revealed a considerable reduction in the number and immunostaining of the peptide-containing cells and nerves. Concentrations of regulatory peptides in the rectum are thus reduced in association with intrinsic but not extrinsic autonomic neuropathy.

Topics: Autonomic Nervous System; Biopsy; Chagas Disease; Chronic Disease; Gastrointestinal Hormones; Humans; Intestinal Diseases, Parasitic; Nervous System Diseases; Rectum; Somatostatin; Substance P; 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