Lamina Propria Of Villi Research Articles

Effects of Long-Term Dietary Zinc Oxide Nanoparticle on Liver Function, Deposition, and Absorption of Trace Minerals in Intrauterine Growth Retardation Pigs.

To investigate the long-term effects of dietary zinc oxide nanoparticle (Nano-ZnO, 20-40 nm) on the relative organ weight, liver function, deposition, and absorption of trace minerals in intrauterine growth retardation (IUGR) pigs, piglets were allocated to NBW (6 normal birth weight piglets fed basal diets), IUGR (6 IUGR piglets fed basal diets) and IUGR+NZ (6 IUGR piglets fed basal diets + 600 mg Zn/kg from Nano-ZnO) groups at weaning (21 days of age), which were sampled at 163 days of age. There were no noteworthy changes in the relative weight of organs, hepatic histomorphology, serum alkaline phosphatase, glutamic pyruvic transaminase and glutamic oxalacetic transaminase activities, and Mn, Cu, and Fe concentrations in leg muscle, the liver, the tibia, and feces among the IUGR, NBW, and IUGR+NZ groups (P>0.05), and no intact Nano-ZnO in the jejunum, liver, and muscle was observed, while dietary Nano-ZnO increased the Zn concentrations in the tibia, the liver, serum, and feces (P<0.05) and mRNA expression of metallothionein (MT) 1A, MT2A, solute carrier family 39 member (ZIP) 4, ZIP14, ZIP8, divalent metal transporter 1, solute carrier family 30 member (ZnT) 1, ZnT4 and metal regulatory transcription factor 1, and ZIP8 protein expression in jejunal mucosa (P<0.05). Immunohistochemistry showed that dietary Nano-ZnO increased the relative optical density of ZIP8 (mainly expressed in cells of brush border) and MT2A (mainly expressed in villus lamina propria and gland/crypt) (P<0.05). In conclusion, long-term dietary Nano-ZnO showed no obvious side effects on the development of the major organs, liver function, and metabolism of Cu, Fe, and Mn in IUGR pigs, while it increased the Zn absorption and deposition via enhancing the expression of transporters (MT, ZIP, and ZnT families) in the jejunum, rather than via endocytosis as the form of intact nanoparticles.

Immunogenicity of a live bivalent non-enterotoxigenic Escherichia coli (non-ETEC) vaccine and dietary clinoptilolite efficacy against postweaning diarrheal disease of pigs due to F4+ and F18+ ETEC strains

No safe and effective vaccine exists against porcine enterotoxigenic Escherichia coli (ETEC) strains, which are the etiological agents of post-weaning diarrhoea (PWD), economically one of the most significant diseases of swine, which encountered for major productive losses in swine industry worldwide. The current study was designed to evaluate: (1) efficacy of an oral bivalent F4ac+/F18ac+ non-ETEC live vaccine candidate (VACCINE) in stimulating systemic and intestinal cellular immunity in 4-week-old weaned pigs, (2) the onset and duration of protective immunity of weaned pigs against naturally occurring PWD during the period of 6 weeks following weaning, and (3) the dietary supplement potential of zeolite clinoptilolite (CPL), an antimicrobial mineral and/or immunomodulator/ vaccine adjuvant (VACCINE + CPL). The pigs immunized either with the VACCINE or its combination with dietary CPL had significantly increased body weight gain from Day 7 to Day 42 (P&lt;0.05) of the experiment, as compared to the control pigs (CONTROLS). Conversely, the pigs that were only supplemented with CPL had mostly significantly lower (P&lt;0.05) body weight. The pigs that received VACCINE + CPL were neither diarrheic nor were there any mortalities during the entire period of the experiment. On Day 42 the total bacterial load in the jejunum was much lower in the pigs from all three principal groups than in the CONTROLS (30 x 108 vs. 18 x 107 vs. 14 x 107 vs. 13 x 107 CFU/mL, respectively). Regarding CD4+ and CD8+ T cells, specific immunization with either VACCINE or with VACCINE + CPL stimulated a significantly higher proportion of these cells (P&lt;0.05) from Day 7 to Day 42 of the experiment. Quite similar findings were obtained for CD21+ B cells, as their proportion was significantly elevated in the pigs treated with either VACCINE or VACCINE + CPL (P&lt;0.05 and P&lt;0.05, respectively). The pigs from the VACCINE + CPL group had a significantly higher proportion of CD45+ lymphoid cells than the pigs from the CONTROL group (P&lt;0.05). Quite sparsely distributed CD45RA+ naïve T lymphocytes were observed in the jejunal lamina propria of the intestinal villi, within the Lieberkühn crypts (LC) and in the submucosa of the CONTROLS and CPL supplemented pigs. The treatment with the VACCINE induced moderate recruitment of CD45 RA+ cells within both the IFA and FA of the jejunal PP of the pigs 6 weeks following the vaccination. In the CONTROLS, CD45 RC+ memory T cells were not abundant and were mostly dispersed in the middle of the villous lamina propria, but only rarely adjacent to the basal membrane of the intestinal enterocytes. These cells were more frequent within the lamina propria of the villi in the CPL group of pigs than in the CONTROLS. Even more numerous CD45 RC+ memory T cells were observed in the villous lamina propria of the jejunum of the pigs from the VACCINE group. These cells were predominantly found in the villous lamina propria and in the IFA, but were less frequent in the FA of the jejunal PP of the pigs that received the VACCINE and CPL. Due to the nature of the disease, challenges in PWD vaccine development will continue to exist. Although our research approach was at least partially successful, developing a safe and immunogenically effective live oral vaccine against PWD that will provide solid protection and sustained cellular and humoral immune responses remains a significant challenge.

Low potassium disrupt intestinal barrier and result in bacterial translocation

BackgroundBacterial translocation was observed in critical illness and patients with chronic diseases such as liver cirrhosis and chronic kidney disease (CKD). Hypokalemia is a common complication in these diseases. Whether low potassium diet may increase intestinal permeability and result in bacterial translocation lack of evidence. The present study was aimed to investigate the potential effects of LK on intestinal permeability.MethodsGrade 8-week-old male Bal B/C mice were randomly placed either on a normal potassium (NK) mouse chow or a low potassium (LK) diet for 28 days. Intestinal permeability and expression of tight junction proteins were compared between the two groups.ResultsCompared with the NK group, the mice in LK group had significantly lower serum potassium level, increased levels of plasmas endotoxin and plasma d-lactate. The bacterial translocation was higher and in occurred mainly in mesenteric lymph nodes (MLN), liver and spleen. The pathologic change of small intestine was obvious with thinner villus lamina propria, shorter crypt depth and thinner intestinal wall. Slight increases in the expression of proteins and mRNA levels of both claudin-1 and claudin-2 were observed in LK group.ConclusionsLow potassium diet could increase intestinal permeability and thereby lead to bacterial translocation, which was suspected to result from impaired intestinal epithelial barrier and biological barrier.

Leukocyte numbers and intestinal mucosal morphometrics in horses with no clinical intestinal disease.

Healthy horses and other animals have large numbers of resident leukocytes in the intestinal wall, but there is scant information regarding which and how many leukocytes are normally present in the equine intestinal wall. Our aim was to provide a reference range of leukocytes in the intestinal mucosal and submucosal propria of normal horses. We included in our study intestinal tissues from 22 Thoroughbred racehorses with no clinical intestinal disease, which had been euthanized because of catastrophic musculoskeletal injuries. Neutrophils, lymphocytes, eosinophils, macrophages, and plasma cells were counted in 5 random 17,600-µm2 areas of villus lamina propria of the duodenum, jejunum, and ileum, and deep lamina propria of the duodenum, jejunum, ileum, right ventral colon, left ventral colon, left dorsal colon, right dorsal colon, and small colon. Other features investigated in the same intestinal segments included villus height and width (small intestine), presence of ciliated protozoa, Paneth cells number, subcryptal leukocyte layers (number of leukocyte layers between the bottom of the crypts and the muscularis mucosae), and submucosal leukocytes. Lymphocytes were the most numerous cells in all segments analyzed, followed by plasma cells, eosinophils, macrophages, and neutrophils. Eosinophil numbers were significantly higher in both lamina propria and submucosa of the large intestine than in the small intestine. The duodenum had shorter and thinner villi than either jejunum or ileum. The data provided from our study will be useful for diagnosticians examining inflammatory processes in the intestinal tract of horses.

Upregulation of signal transducer and activator of transcription 3 in dogs with chronic inflammatory enteropathies.

BackgroundIn inflammatory bowel disease (IBD) in humans, phosphorylated signal transducer and activator of transcription 3 (pSTAT3) is upregulated in mucosal epithelial cells and correlates with clinical severity.Hypothesis/ObjectiveTo investigate the expression pattern of pSTAT3 in the mucosa of dogs with chronic inflammatory enteropathy (CIE) and explore correlations between its expression and clinical and histopathological severity scoring.AnimalsTwenty‐eight canine CIE patients grouped into food‐responsive enteropathy (FRE; 9), steroid‐responsive enteropathy (SRE; 10), and protein‐losing enteropathy (PLE; 9). Ten healthy beagle dogs served as controls (CO).MethodsRetrospective case control study. Immunohistochemistry was used to detect pSTAT3 in canine duodenal mucosa samples.ResultsCompared to CO, SRE (P < .001) and PLE (P < .001) dogs had significantly higher pSTAT3 expression in the villus epithelium. The SRE group had a significantly higher expression in the villus lamina propria (VLP) compared to controls (P = .009). In the crypt epithelium (CE), all CIE dogs had significantly higher pSTAT3 expression (FRE, P = .002; SRE, P = .003; PLE, P < .001) compared to CO. In the lamina propria crypt region (CLP), dogs with FRE (P = .04) and SRE (P = .03) had significantly upregulated pSTAT3 compared to controls. A positive correlation was found between canine chronic enteropathy clinical activity index (CCECAI) scoring and pSTAT3 expression for both epithelial (rho = .541; P < .001) and crypt regions (rho = .32; P = .02).Conclusions and Clinical ImportancepSTAT3 is upregulated in CIE in dogs, correlates with clinical severity, and may be helpful as a clinical marker in dogs with CIE.

Rare Finding of Concomitant Pseudomelanosis of Stomach and Duodenum

Introduction: Pseudomelanosis (PM) of the stomach and duodenum is a rare entity and a striking finding diagnosed by upper endoscopy. It is characterized by dark pigmented stripes that, while benign in nature, are histologically composed of pigment-laden macrophages. We describe the case of an 83-year-old woman, with a complicated medical history, who was was found to have both pseudomelanosis gastri and duodeni. Although both are rare, gastric pseudomelanosis appears to be even more unusual than duodenal pseudomelanosis, with few reported cases documented in the literature thus far. Case Presentation: An 83-year-old woman past medical history of atrial fibrillation, chronic obstructive pulmonary disease, pulmonary hypertension, heart failure, non-Hodgkin Lymphoma, monoclonal gammopathy of undetermined significance (MGUS) who was referred to gastroenterology by cardiology for a determination of her bleeding risk in the context of an episode of self resolved gastrointestinal bleeding (melena) while on anticoagulation (Rivaroxaban). Patient underwent a diagnostic upper endoscopy which revealed mucosal changes in the stomach and duodenum consistent with pseudomelanosis (Figure 1&2). Pathology report revealed of pigment-laden macrophages in the lamina propria.Figure: Pseudomelanosis in the gastric antrum.Figure: Pseudomelanosis in the duodenum.Discussion: Although a benign finding, gastric and duodenal pseudomelanosis is such an infrequent and manifest condition that it can lead to an extensive, expensive, and ultimately unnecessary work-up. It is very rare to see both pseudomelanosis of stomach an duodenum in the same patient. It involves the collection of dark pigmented granules inside the macrophages of the duodenal villi's lamina propria, usually within the apical tips. Electron probe microanalysis has shown that these macrophages often contain lipomelanin, ceroid, iron sulfide, and hemosiderin. However, gastric and duodenal pseudomelanosis represents a diagnostic challenge for physicians because the precise etiology and clinical significance of this condition remain to be determined. It is typically seen in older women and has been associated with several clinical conditions, some of which include: hypertension, hemochromatosis, diabetes, chronic renal disease, and gastrointestinal bleeding. Gastric and duodenal pseudomelanosis has also been seen in connection with medications containing iron sulfate as well as certain antihypertensive medications, like furosemide, hydrochlorothiazide, propranolol, and hydralazine.

Assessment of organosomatic indices and histopathological changes in vital organs of &lt;i&gt;Clarias gariepinus&lt;/i&gt; juveniles fed graded levels of boiled sunflower (&lt;i&gt;Helianthus annuus&lt;/i&gt;) seed meal

This study investigated the effects of substituting boiled sunflower seed meal (BSSM) for soybean meal (SBM) on the organosomatic indices and histopathological changes in the liver, kidney and intestine of Clarias gariepinus juveniles for fifteen weeks. BSSM was substituted for SBM at 0, 20, 40, 60, 80 and 100% in formulating six isonitrogenous (40% crude protein) and isocaloric (4651.5 Kcal/kg) diets. Diets were fed twice daily to triplicate groups of 360 C. gariepinus juveniles inside eighteen rectangular tanks (20 fish per tank). The result showed that hepatosomatic index (HSI) was significantly highest (3.11%) in the fish fed 0% BSSM diet and lowest (0.87%) in those fed 100% BSSM inclusion. HSI values progressively decreased with increasing inclusion level of BSSM. Kidney-somatic index (KSI) was highest (0.74%) in fish fed 20% BSSM inclusion and least (0.32%) in those fed 100% inclusion. Intestino-somatic index (ISI) was superior (3.82%) in fish fed 100% BSSM inclusion and least (3.16%) in those fed 40%. The liver, kidney and intestine of fish fed 0 and 20% BSSM inclusions showed no visible signs of damage. However, fish fed higher BSSM inclusions (>20%) revealed extensive hepatic degeneration, periportal congestions and severe diffuse cytoplasmic vacuolations of hepatocytes. Kidney tubules of fish fed higher BSSM inclusions exhibited diffuse interstitial congestions, diffuse swelling, epithelial vacuolations and degeneration as well as necrosis. Intestinal changes in fish fed higher BSSM inclusions included reduced sub-mucosal width, markedly stunted villi, moderate erosion of villi's epithelia, hyperplastic villi, necrosis of enterocytes and inflammatory cells in villi's lamina propria . Inclusion of boiled sunflower seed meal beyond 20% in C. gariepinus ' diet could cause adverse histological alterations. Keywords: Clarias gariepinus , Sunflower seed meal, Histopathology, Hepatosomatic index, Anti-nutrients

Ethanol and age enhances fluoride toxicity through oxidative stress and mitochondrial dysfunctions in rat intestine

Fluoride toxicity and alcohol abuse are the two serious public health problems in many parts of the world. The current study was an attempt to investigate the effect of alcohol administration and age on fluoride toxicity in rat intestine. Six and 18 months old female Sprague Dawley rats were exposed to sodium fluoride (NaF, 25 mg/kg), 30 % ethanol (EtOH, 1 ml/kg), and NaF+EtOH (25 mg/kg+1 ml/kg) for a period of 20, 40, and 90 days. The levels of lipid peroxidation were increased, while the content of reduced glutathione, total, and protein thiol was decreased with NaF treatment. Under these conditions, animals showed an age-related decline in the activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and glutathione-S-transferase which were further aggravated upon NaF or/and EtOH treatment. Mitochondrial respiration rate and the activities of complexes I, II, and IV enzymes of electron transport chain were decreased, while the levels of nitric oxide and citrulline were increased with age and NaF or/and EtOH treatment. Histological examination revealed large reactive lymphoid follicles, excess of lymphocytes in lamina propria of villi, villous edema, focal ileitis, necrosis of villi, and ulceration in NaF- or/and EtOH-treated animals in both the age groups. These findings suggest that fluoride mediate its toxic effects on intestine through oxidative stress and mitochondrial dysfunctions which are further augmented with alcohol consumption and advancing age.

Histology of Intestinal Allografts

Acute rejection of a small-bowel transplant is often difficult to diagnose due to complicated immune responses. The present study aimed to elucidate the specific immune responses involved in intestinal transplant rejection. We correlated immunohistologic findings with an increase in crypt apoptosis, which has been commonly accepted as a criterion for the diagnosis of acute cellular rejection (ACR). Of 8 patients who received an intestinal allograft at Kyoto University Hospital, biopsy specimens from 7 patients were assessed immunohistologically with antibodies against 20 types of lymphocytic antigens including CD3, CD4, CD8, CD79a, CD20, IgG, and T-cell receptor, along with assessment of the patients' clinical courses. It was revealed that, in addition to apoptotic crypts, T-lymphocyte apoptosis and phagocytosis of apoptotic bodies in the lamina propria of villi were findings of ACR; both were observed in all cases. Immunostaining of the Fas ligand, one of the apoptosis-inducing molecules, was useful for the identification of the apoptotic bodies in the lamina propria of villi. Apoptotic body phagocytosis may be a surrogate diagnostic finding of grafts undergoing ACR.

Effect of the IGF-1/PTEN/Akt/FoxO signaling pathway in the duodenal mucosa of rats subjected to water immersion and restraint stress

The insulin growth factor 1/phosphatase and tensin homologue deleted on chromosome 10/Akt/forkhead box (IGF-1/PTEN/Akt/FoxO) signaling pathway reportedly exhibits gastroprotective effects by reducing water immersion and restraint stress (WRS)-induced gastric mucosal cell apoptosis. We examined the expression and localization of IGF-1, PTEN, Akt, and FoxO proteins, caspase-3 activity, and the number of apoptotic cells in the duodenal mucosa of rats subjected to WRS to confirm whether the IGF-1/PTEN/Akt/FoxO signaling pathway has a role in the duodenal mucosa. The results indicated that WRS enhanced cell apoptosis in the duodenal mucosa. In addition, in normal rats, PTEN was found mainly in the cellular cytoplasm of the duodenal glands and lamina propria of villi. IGF-1 and total Akt were observed in the cellular cytoplasm of the duodenal glands. In addition, total Akt was found in the cellular cytoplasm of the myenteric plexus. FoxO3a and FoxO4 were primarily concentrated in the cellular cytoplasm of the lamina propria. Specifically, PTEN, FoxO3a and FoxO4 were also localized in the cellular cytoplasm of lamina propria of restituted villi in the duodenal mucosa of rat subjected to WRS. In addition, messenger RNA transcript levels of IGF-1, PTEN, Akt1, Akt2, FoxO3, and FoxO4 were upregulated in the duodenal mucosa, with a peak between the 4th and 8th day after 7 h of WRS. Furthermore, the results also suggested that Akt3 messenger RNA transcript levels in the duodenal mucosa of rats after WRS showed no significant differences compared with those in the non-WRS group. Collectively, our results implied that the IGF-1/ PTEN/Akt/FoxO signaling pathway was effective in regulating cellular apoptosis in the duodenal mucosa of rats after WRS.

Infection of Calves with Bovine Norovirus GIII.1 Strain Jena Virus: an Experimental Model To Study the Pathogenesis of Norovirus Infection

The experimental infection of newborn calves with bovine norovirus was used as a homologous large animal model to study the pathogenesis of norovirus infection and to determine target cells for viral replication. Six newborn calves were inoculated orally with Jena virus (JV), a bovine norovirus GIII.1 strain, and six calves served as mock-inoculated controls. Following infection, calves were euthanized before the onset of diarrhea (12 h postinoculation [hpi]), shortly after the onset of diarrhea (18 to 21 hpi), and postconvalescence (4 days pi [dpi]). Calves inoculated with JV developed severe watery diarrhea at 14 to 16 hpi, and this symptom lasted for 53.5 to 67.0 h. Intestinal lesions were characterized by severe villus atrophy together with loss and attenuation of villus epithelium. Viral capsid antigen (JV antigen) was detected by immunohistochemistry in the cytoplasm of epithelial cells on villi. In addition, granular material positive for JV antigen was detected in the lamina propria of villi. Lesions first appeared at 12 hpi and were most extensive at 18 to 19 hpi, extending from midjejunum to ileum. The intestinal mucosa had completely recovered at 4 dpi. There was no indication of systemic infection as described for norovirus infection in mice. JV was found in intestinal contents by reverse transcription-PCR (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) as early as 12 hpi. Fecal shedding of the virus started at 13 hpi and stopped at 23 hpi or at necropsy (4 dpi), respectively. Throughout the trial, none of the control calves tested positive for JV by ELISA or RT-PCR.

Modulation of lipid peroxidation and antioxidant defense systems in rat intestine by subchronic fluoride and ethanol administration

Excessive consumption of fluoride and ethanol has been identified as injurious to human health. Fluoride and ethanol co-exposures are commonly seen among the alcoholics residing in endemic fluoride areas worldwide. This study was undertaken to examine the modulation of lipid peroxidation and antioxidant defense systems in rat intestine by subchronic fluoride and ethanol administration. Female Sprague-Dawley rats were divided into four groups: group I (control), group II (fluoride was given orally at a dose of 25 mg/kg body weight), group III (30% ethanol was given orally at a dose of 1 mL/kg body weight), and group IV (a combination of fluoride and ethanol was administered orally at the dose described for groups II and III). Lipid peroxidation was elevated ( P < .05) in intestine of rats by fluoride or ethanol treatments for 20 or 40 days. However, glutathione content was reduced by fluoride (32 and 44%) and ethanol (21 and 40%) treatments after 20 and 40 days, respectively. Fluoride-exposed animals showed reduction ( P < .05) in the activities of superoxide dismutase (22 and 42%), catalase (30 and 37%), glutathione peroxidase (22 and 35%), glutathione reductase (32 and 34%), and glutathione- S-transferase (24 and 30%) after 20 and 40 days. A similar decrease ( P < .05) in the activities of these enzymes was also noticed in animals exposed to ethanol for 20 or 40 days. The observed changes in lipid peroxidation, reduced glutathione levels, and enzyme systems were further augmented in intestine of rats exposed to fluoride and ethanol together. Intestinal histology showed large reactive lymphoid follicles along with mild excess of lymphocytes in lamina propria of villi, villous edema, focal ileitis, and necrosis of villi in animals exposed to fluoride and ethanol for 40 days. These findings suggest that fluoride and ethanol exposure induces considerable changes in lipid peroxidation, antioxidant defense, and morphology of rat intestine, which may affect its functions.

Epidermal growth factor receptor signaling modulates chemokine (CXC) ligand 5 expression and is associated with villus angiogenesis after small bowel resection

Adaptive villus growth after a massive small bowel resection (SBR) is an important response to the loss of intestinal surface area and is regulated via epidermal growth factor receptor (EGFR) signaling. Increased levels of the proangiogenic chemokine ligand 5 (CXCL5) have been found within the adapting bowel in which angiogenesis is increased. We sought to determine whether CXCL5 was expressed specifically in the villus mesenchymal zone (area of increased blood vessel growth) and whether this expression was affected by EGF. C57BL/6J mice were subjected to sham operation (bowel transaction with reanastomosis) or 50% proximal SBR. The remnant intestine was harvested, and the villus lamina propria was isolated by laser capture microdissection. The expression of CXCL5 messenger RNA (mRNA) was analyzed using real-time polymerase chain reaction (RT-PCR). Furthermore, CXCL5 mRNA levels were determined in EGF-stimulated human umbilical vein endothelial cells (HUVECs). A 2.39-fold increase (P < .05) in CXCL5 mRNA occurred in the lamina propria after SBR. In addition, villus height was found to be related directly to the degree of CXCL5 mRNA (R(2) = 0.97) expression. HUVECs treated with EGF demonstrated a 9-fold increase in CXCL5 mRNA expression. The villus growth observed in resection-induced adaptation is associated with increased expression of the chemokine CXCL5 within the lamina propria. Because EGF enhances CXCL5 expression directly in endothelial cells, EGFR-directed proangiogenic gene expression may be a critical mechanism for adaptive ileal villus growth.

Mechanisms of postburn intestinal barrier dysfunction in the rat: roles of epithelial cell renewal, E-cadherin, and neutrophil extravasation.

Our group has previously shown that the intestinal epithelium exhibits increased postburn barrier permeability and bacterial translocation associated with deranged neutrophil activity. The purpose of this investigation is to explore possible underlying intestinal structural mechanisms, leading to those functional changes with emphasis on (1) neutrophil influx and extravasation in the intestinal lamina propria 1-3 days after burn and (2) enterocyte proliferation, migration, apoptosis, and E-cadherin junctional epithelium levels 3 days after burn. Freshly isolated ileum specimens were quick frozen, then cut by a cryostat into 30-micron-thick sections. Sections from day 1 postburn rats were immunostained with (1) anti-granulocyte or anti-elastase antibodies to assess neutrophil influx or (2) combined anti-granulocyte and anti-von Willebrand factor double immunolabeling to compare levels of neutrophil extravasation. Sections from day 3 postburn rats were immunostained with (1) bromodeoxyuridine immunohistochemistry 1, 3, 6, or 18 hrs after bromodeoxyuridine injection to assess enterocyte proliferation and migration, (2) cytokeratin-18 M30-immunohistochemistry to compare levels of enterocyte apoptosis, and (3) E-cadherin immunohistochemistry to compare junctional E-cadherin integrity. Ileal myeloperoxidase activity and bacterial translocation of Enterococcus faecalis were assessed biochemically and by E. faecalis-specific bacterial cultures, respectively, in day 3 postburn rats. : Research laboratories in a medical center and an academic institution. Male Sprague-Dawley rats given sham treatment or treatment as a burn model with full-thickness skin scald over 30% total body surface area. We report (1) increased levels of neutrophil influx and extravasation in villi lamina propriae, including elastase-positive cells (postburn day 1), (2) heightened levels of intestinal myeloperoxidase activity (postburn day 3), (3) decreased levels of epithelial cell proliferation, migration, and E-cadherin (postburn day 3), and (4) increased enterocyte apoptosis and E. faecalis bacterial translocation (postburn day 3). Based on these structural and functional abnormalities, we propose a mechanism for burn injury-related intestinal barrier dysfunction that includes increased trans- and para-cellular leakage caused by impaired enterocyte renewal and decreased junctional E-cadherin levels subsequent to increased neutrophil influx and extravasation within the villus lamina propria microenvironment.

Morphometric evaluation of immunoglobulin A-containing and immunoglobulin G-containing cells and T cells in duodenal mucosa from healthy dogs and from dogs with inflammatory bowel disease or nonspecific gastroenteritis

Abstract Objective To investigate the distribution of IgA- and IgG-containing cells and T cells in the villi of duodenal mucosa from healthy dogs and from dogs with inflammatory bowel disease (IBD) or gastroenteritis. Design Case-control study. Animals 28 dogs, grouped according to clinical and histologic criteria: 11 dogs with IBD, 8 dogs with nonspecific gastroenteritis, and 9 healthy dogs. Procedure Endoscopic biopsy specimens of duodenal mucosa from each dog were stained specifically for IgA and IgG heavy chains and pan T-cell (CD3) antigen, using immunoperoxidase techniques. Morphometric analysis, performed via an image-analysis system, was used to count IgA- and IgG-containing cells and T cells within paired contiguous villi from each dog. Results T cells were the predominant immune cell type in all groups of dogs. Significant differences in the villus distribution of IgA- and IgG-containing cells and T cells were not observed. Healthy dogs had significantly higher T-cell counts than had dogs with IBD or gastroenteritis. Dogs with nonspecific gastroenteritis had a significantly higher concentration of IgA-containing cells than the other groups of dogs had. Significant group differences for IgG-containing cells also were evident, with dogs with IBD having the lowest cell counts. Conclusions and Clinical Relevance High concentrations of IgA- and IgG-containing cells and T cells in the villus lamina propria cannot be reliably used to distinguish IBD from other intestinal disorders in dogs. Evaluation of T cells may be the most discriminatory method for differentiating dogs with IBD from clinically normal dogs via examination of intestinal biopsy specimens. (Am J Vet Res 1996; 57:697–704)

Endogenous expression of type II cGMP-dependent protein kinase mRNA and protein in rat intestine. Implications for cystic fibrosis transmembrane conductance regulator.

Certain pathogenic bacteria produce a family of heat stable enterotoxins (STa) which activate intestinal guanylyl cyclases, increase cGMP, and elicit life-threatening secretory diarrhea. The intracellular effector of cGMP actions has not been clarified. Recently we cloned the cDNA for a rat intestinal type II cGMP dependent protein kinase (cGK II) which is highly enriched in intestinal mucosa. Here we show that cGK II mRNA and protein are restricted to the intestinal segments from the duodenum to the proximal colon, with the highest amounts of cGK II protein in duodenum and jejunum. cGK II mRNA and protein decreased along the villus to crypt axis in the small intestine, whereas substantial amounts of both were found in the crypts of cecum. In intestinal epithelia, cGK II was specifically localized in the apical membrane, a major site of ion transport regulation. In contrast to cGK II, cGK I was localized in smooth muscle cells of the villus lamina propria. Short circuit current (ISC), a measure of Cl- secretion, was increased to a similar extent by STa and by 8-Br-cGMP, a selective activator of cGK, except in distal colon and in monolayers of T84 human colon carcinoma cells in which cGK II was not detected. In human and mouse intestine, the cyclic nucleotide-regulated Cl- conductance can be exclusively accounted for by the cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channel. Viewed collectively, the data suggest that cGK II is the mediator of STa and cGMP effects on Cl- transport in intestinal-epithelia.

Haemorhagic enteritis virus infection in turkeys: A comparison of virulent and avirulent virus infections, and a proposed pathogenesis

Five-week-old specific-pathogen-free turkey poults were inoculated orally with either virulent or avirulent haemorrhagic enteritis virus (HEV) and killed sequentially from 3 h to 10 days post-inoculation. Tissues were examined by light and electron microscopy, and immunoperoxidase staining. Lesions produced were similar for both types of virus. The earliest signs of infection were seen in the spleen with proliferation of the white pulp surrounding the ellipsoids on day 3 post-inoculation. Intranuclear inclusion bodies appeared in lymphoblasts on day 3 and remained until day 5. Necrosis of the white pulp followed the proliferative phase on days 4 and 5, and plasma cells appeared in the red pulp on days 6 and 7. By day 10 the splenic architecture had returned to normal. The liver contained focal random collections of lymphocytes with occasional hepatocellular necrosis beginning on day 3. The bursa had mild lymphoid depletion in the virulent-virus-infected birds on day 6. Bleeding in the duodenum occurred on day 5 in virulent-virus-infected birds and was associated with small numbers of necrotic cells in the villus lamina propria. All other organs remained unchanged throughout the study. A pathogenesis for HEV infection is proposed. Virus replicates in lymphoid cells within the spleen causing first proliferation and then necrosis of the cells followed by production of plasma cells which produce specific antibody. Replication does not occur in any other organ, but virus-infected lymphocytes from the spleen circulate through the other organs of the bird without causing any visible local alterations. Intestinal bleeding occurs as diapedesis without vascular damage and appears to be initiated by mediators of the inflammatory response.

50 CORRELATION BETWEEN THE ONTOGENY OF SMALL INTESTINAL MUCOSAL LYMPHOCYTES AND SUCRASE IN THE PREWEANED RAT

Immunoreactive sucrase in villous enterocytes of rat jejunum appears by 21 days of age. We attempted to correlate the ontogeny and type of intraepithelial and lamina propria lymphocytes during the same period. Suckled Sprague-Dawley rat pups (0 · 24 days) were sacrificed at regular intervals. The distal jejunum was removed and 4· to 5·micron frozen sections were cut, fixed in absolute methanol, and stained with mouse monoclonal antibodies BBC 1/35 (sucrase), MRC OX-4 (B-cell), MRC OX-8 (T-suppressor), W3/25 (T-helper), MRC OX-19 (pan T-cell) and W3/13HLK (pan T-cell). The sections were counterstained with goat anti-mouse IgG-FITC conjugated antiserum. The sections were then stained with Evans blue for morphologic definition and evaluated for type, relative numbers and location of lymphocytes. T-suppressor cells were present in the intraepithelial and lamina propria areas up to age 12 days and were absent between 12 and 17 days. From 17 to 24 days, T-suppressor cell levels increased and approached adult levels. B-cells were present at all ages in the lamina propria of villi and crypts. T-helper cells were found irregularly; pan T-cell levels increased from 21 days onward. Our observations confirm and extend those of Lyscom and Brueton (Clin Exp Immunol 54:158-162, 1983) in which the number of T-suppressor intraepithelial cells increased after 21 days of life. We report that this increase coincides with the expression of sucrase by villous enterocytes.

Development of dome epithelium in gut-associated lymphoid tissues: association of IgA with M cells.

The dome epithelium (DE), which covers gut-associated lymphoid tissues (GALT) and provides both a protective barrier over lymphoid follicles and a route for antigen uptake from the gut, develops in rabbit appendix (caecum) during the first week of neonatal life. To determine if secretory immunoglobulins from maternal milk interact with this developing tissue, their interrelationships in neonatal rabbit appendix were examined by use of immunocytochemical techniques. The glycoprotein, secretory component, was not produced by neonatal rabbits less than 15 days old, since neither the membranous nor the free, secreted forms of maternal secretory component were associated with villi or DE of neonates. Immunoglobulin A (IgA), but neither IgG nor IgM, were noted on DE by light microscopy, even though IgG was abundant in the villus lamina propria and vascular spaces. The epithelial IgA was distributed, in a patchy pattern, across the upper dome surface of some two-day-old, and all five-and ten-day old nursing animals, but IgA was not on DE of rabbits prevented from nursing. Immuno-electron microscopy of appendix from nursed rabbits revealed IgA directly over the apical surface of M cells, where it formed a continuous, thick coating without binding to adjacent immature absorptive cells; it was also within apical vacuoles of M cell cytoplasm. The distribution of IgA on the DE of rabbit appendices indicated that in differentiating GALT, maternal IgA reacted preferentially with M cells or pre-M cells, leading to speculation concerning a role for IgA in the development of GALT and in establishment of mucosal immune responses in neonates.

Pathological changes in the midgut epithelium of grayling, Thymallus thymallus L., larvae reared on different kinds of food, and their relation to mortality and growth

Abstract. The histological differentiation of the digestive tract in grayling, Thymallus thymallus L., larvae was studied during the first 20 days after hatching. The normal development was assessed in larvae fed with nauplii of two Anemia strains. These results were compared with a starved control. Grayling larvae reared on lake zoo‐plankton suffered mortality which was ten times higher than that in the Artemia‐fed groups. The histopathology of the zooplankton‐fed larvae was characterized by excessive fat accumulation in the apices of columnar absorptive cells, complete absence of fat transport into the villus lamina propria, and disintegration of enterocyte cell membranes. This pathology is compared with the clinical findings in human abetalipoproteinaemia. It is concluded that the histopathological manifestations and the resulting elevated mortality in larval grayling were provoked by a disturbance of the fat absorption process in the enterocytes. This disturbance is likely to be due to the inability to synthesize chylomicrons. It is further hypothesized that lake plankton either contains a toxic agent which interferes with the build‐up of chylomicrons or is deficient in some lipoprotein moiety which is essential for chylomicron synthesis.