Elevated postischemic tissue injury and leukocyte-endothelial adhesive interactions in mice with global deficiency in caveolin-2: role of PAI-1

Ischemia/reperfusion (I/R)-induced rapid inflammation involving activation of leukocyte-endothelial adhesive interactions and leukocyte infiltration into tissues is a major contributor to postischemic tissue injury. However, the molecular mediators involved in this pathological process are not fully known. We have previously reported that caveolin-2 (Cav-2), a protein component of plasma membrane caveolae, regulated leukocyte infiltration in mouse lung carcinoma tumors. The goal of the current study was to examine if Cav-2 plays a role in I/R injury and associated acute leukocyte-mediated inflammation. Using a mouse small intestinal I/R model, we demonstrated that I/R downregulates Cav-2 protein levels in the small bowel. Further study using Cav-2-deficient mice revealed aggravated postischemic tissue injury determined by scoring of villi length in H&E-stained tissue sections, which correlated with increased numbers of MPO-positive tissue-infiltrating leukocytes determined by IHC staining. Intravital microscopic analysis of upstream events relative to leukocyte transmigration and tissue infiltration revealed that leukocyte-endothelial cell adhesive interactions in postcapillary venules, namely leukocyte rolling and adhesion were also enhanced in Cav-2-deficient mice. Mechanistically, Cav-2 deficiency increased plasminogen activator inhibitor-1 (PAI-1) protein levels in the intestinal tissue and a pharmacological inhibition of PAI-1 had overall greater inhibitory effect on both aggravated I/R tissue injury and enhanced leukocyte-endothelial interactions in postcapillary venules in Cav-2-deficient mice. In conclusion, our data suggest that Cav-2 protein alleviates tissue injury in response to I/R by dampening PAI-1 protein levels and thereby reducing leukocyte-endothelial adhesive interactions.NEW & NOTEWORTHY The role of caveolin-2 in regulating ischemia/reperfusion (I/R) tissue injury and the mechanisms underlying its effects are unknown. This study uses caveolin-2-deficient mouse and small intestinal I/R injury models to examine the role of caveolin-2 in the leukocyte-dependent reperfusion injury. We demonstrate for the first time that caveolin-2 plays a protective role from the I/R-induced leukocyte-dependent reperfusion injury by reducing PAI-1 protein levels in intestinal tissue and leukocyte-endothelial adhesive interactions in postcapillary venules.

Successful azathioprine treatment in an adolescent with chronic enteropathy associated with SLCO2A1 gene: A case report

INTRODUCTION

Chronic nonspecific multiple ulcers of the small intestine (CNSU), an entity with female preponderance and manifestations including anemia and hypoproteinemia reflecting persistent gastrointestinal bleeding and intestinal protein loss, has been considered idiopathic. Umeno et al recently reported that CNSU is caused by loss-of-function mutations in the solute carrier organic anion transporter family member 2A1 gene (SLCO2A1) encoding a prostaglandin transporter, renaming the disorder "chronic enteropathy associated with SLCO2A1 gene mutation" (CEAS). Treatments for chronic enteropathies such as inflammatory bowel disease, including 5-aminosalicylic acid, corticosteroids, azathioprine, and anti-tumor necrosis factor-α antibody, often are ineffective in CEAS, which frequently requires surgery.

CASE PRESENTATION

A 14-year-old girl had refractory anemia and hypoproteinemia for more than 2 years. Video capsule endoscopy showed nonspecific jejunal and ileal ulcers with varied sizes and shapes. She was diagnosed with CEAS resulting from compound heterozygous mutation of the SLCO2A1 gene. After corticosteroid treatment without improvement, azathioprine treatment improved her anemia and edema as hemoglobin and serum protein increased. Video capsule endoscopy 1 year after initiation of azathioprine showed improvement of small intestinal ulcers.

CONCLUSION

Physicians should consider CEAS in patients with refractory anemia, hypoproteinemia, and multiple small intestinal ulcers. Why our patient responded to azathioprine but not to corticosteroids is unclear, but azathioprine might benefit some other patients with CEAS.

Glutamine ameliorates intestinal ischemia-reperfusion Injury in rats by activating the Nrf2/Are signaling pathway

Ischemia-reperfusion (I/R)-mediated intestinal mucosal injury is usually induced by oxygen-derived toxic free radicals from the xanthine oxidase system after reperfusion, but the detailed molecular mechanisms underlying glutamine protection is still unclear. This study aims to elucidate whether glutamine prevents damage to the intestinal mucosa after I/R in rats and to investigate signaling by the Nrf2/ARE pathway induced by GLN in a rat model. Our results revealed that Glutamine pretreatment reduced jejunum injury and microvascular hyper-permeability induced by I/R. MDA level significantly increased while the SOD and GSH-Px levels decreased in the I/R group compared to the sham group and the GLN-I/R group. Both the mRNA and protein levels of the Nrf2 and HO-1 were significantly elevated by GLN pretreatment when compared to the I/R group. GLN treatment also elevated Bcl-2 levels, and accordingly suppressed apoptotic damage in the jejunum cells shown by decreased cleaved caspase-3 level. Mechanistic investigation revealed that GLN treatment augmented binding of Nrf2 onto Bcl2 gene promoter. These results indicate that glutamine has protective effects on I/R in vivo by activating the Nrf2/ARE signaling pathway to inhibit ROS production and reduce intestinal apoptosis.

Inhibition of Bach1 ameliorates indomethacin-induced intestinal injury in mice

BTB and CNC homolog 1 (Bach1) is a transcriptional repressor of heme oxygenase-1 (HO-1). It plays an important role in the feedback regulation of HO-1 expression, which protects cells from various insults including oxidative stress and inflammatory cytokines. However, the role of Bach1 in intestinal inflammation remains unclear. In this study, the role of Bach1 in intestinal mucosal injury was elucidated using 8-week-old female C57BL/6 (wild-type) and homozygous Bach1-deficient C57BL/6 mice. Intestinal mucosal injuries induced by a single subcutaneous administration of indomethacin were evaluated macroscopically, histologically, and biochemically. Mucosal protein content and chemokine mRNA levels were determined by real-time PCR. Our results showed that the indomethacin-induced intestinal injury was remarkably improved in Bach1-deficient mice. Histological examination showed that the area of injured lesion was decreased in Bach1-deficient mice compared to wild-type mice. Administration of indomethacin induced expression of inflammatory chemokines such as KC, MIP1alpha and MCP1, which was suppressed in Bach1-deficient mice. Myeloperoxidase activity in the intestinal mucosa was also significantly decreased in Bach1-deficient mice. Additionally, Bach1 deficiency enhanced immunopositivity of HO-1 in the intestinal mucosa after indomethacin administration. Disruption of the Bach1 gene thus caused inhibition of mucosal injury, indicating that inhibition of Bach1 may be a novel therapeutic strategy for treating indomethacin-induced intestinal injury.

Extensive jejunal diverticulosis in a family, a matter of inheritance?

Diverticulosis of the jejunum is a rare finding (0.06 to 1.3%). Possible complications are bacterial overgrowth, malabsorption, bleeding, mechanical obstruction, volvulus and perforation. At present only one case report on familial jejunal diverticulosis has been published. We describe three patients with jejunal diverticulosis within one family, which might suggest inheritance.

[Multiple enterolithiasis, coexisting with bladder and gallbladder lithiasis, associated with colon adenocarcinoma]

Enteroliths are calculi primarily formed in the intestine. Enterolithiasis is a rare condition frequently associated with intestinal stasis. Usually it causes no symptoms in most cases, but it can be an important diagnostic clue in patients presenting intestinal occlusive symptoms. We report a case of multiple enterolithiasis, very infrequent pathology, coexisting with bladder and gall bladder lithiasis in a patient with colon adenocarcinoma. Diagnosis was made by X-rays and CT images. Calculi were analysed by several methods: chemical, infrared spectroscopy, stereoscopic microscopy and atomic emission spectroscopy; they showed that caluli are made up of organic material and whilokita (calcium and magnesium ortophosphate). No risk factors for lithogenesis were found in this patient excluding the intestinal stasis caused by intestinal narrowing as a result of adenocarcinoma. Genetic factors are suggested as main contributors to hyperlithogenesis observed in this patient. The physiopathological conditions were studied in depth and literature about this subject reviewed.

Loss of heterozygosity at chromosome 9p21 is a frequent finding in enteropathy-type T-cell lymphoma

Enteropathy-type T-cell lymphoma (ETL) and ulcerative jejunitis (UJ) are rare disorders often occurring in patients with coeliac disease. The genetic events associated with the accumulation of intraepithelial lymphocytes in coeliac disease and tumour development are largely unknown. Deletions at chromosome 9p21, which harbours the tumour suppressor genes p14/ARF, p15/INK4b, and p16/INK4a, and 17p13, where p53 is located, are associated with the development and progression of lymphomas. To examine whether deletions at 9p21 and 17p13 play a role in ETL, 22 cases of ETL and seven cases of UJ were screened for loss of heterozygosity (LOH) by tissue microdissection and polymerase chain reaction (PCR) analysis for microsatellite markers. Furthermore, p53 and p16 protein expression was examined by immunohistochemistry. In addition, polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) analysis for detection of mutations in exons 5-8 of the p53 gene was performed in five cases of ETL and three cases of UJ. LOH was found in at least one microsatellite marker at the 9p21 locus in 8 of 22 (36%) ETLs, but not in UJ. Five of nine (56%) tumours composed of large cells showed LOH at 9p21, as opposed to two of eight (25%) tumours with small- or medium-sized cell morphology. The region spanning the p14/p15/p16 gene locus was most frequently affected (five cases); LOH at these markers coincided with loss of p16 protein expression in all of these cases. p53 overexpression was demonstrated in all ETLs examined and in four of seven cases of UJ. However, no alterations of the p53 gene were detected by LOH or PCR-SSCP analysis. The results of this study show that LOH at chromosome 9p21 is frequent in ETL, especially in tumours with large cell morphology; this finding suggests that gene loss at this locus may play a role in the development of ETL.

IL-18 regulates intestinal mastocytosis and Th2 cytokine production independently of IFN-gamma during Trichinella spiralis infection

Expulsion of the gastrointestinal nematode Trichinella spiralis is associated with pronounced mastocytosis mediated by a Th2-type response involving IL-4, IL-10, and IL-13. Here we demonstrate that IL-18 is a key negative regulator of protective immune responses against T. spiralis in vivo. IL-18 knockout mice are highly resistant to T. spiralis infection, expel the worms rapidly and subsequently develop low levels of encysted muscle larvae. The increased speed of expulsion is correlated with high numbers of mucosal mast cells and an increase in IL-13 and IL-10 secretion. When normal mice were treated with rIL-18 in vivo, worm expulsion was notably delayed, and the development of mastocytosis and Th2 cytokine production was significantly reduced. The treatment had no effect on intestinal eosinophilia or goblet cell hyperplasia but specifically inhibited the development of mastocytosis. Addition of rIL-18 to in vitro cultures of bone marrow-derived mast cells resulted in a significant reduction in cell yields as well as in the number of IL-4-secreting mast cells. In vivo treatment of T. spiralis-infected IFN-gamma knockout mice with rIL-18 demonstrated that the inhibitory effect of IL-18 on mastocytosis and Th2 cytokine secretion is independent of IFN-gamma. Hence, IL-18 plays a significant biological role as a negative regulator of intestinal mast cell responses and may promote the survival of intestinal parasites in vivo.

Neuromuscular dysfunction in the jejunum and colon of human leukocyte antigen B27 transgenic rats

HLA-B27 transgenic rats are a model of spontaneous gastrointestinal inflammation associated with expression of human leukocyte antigen (HLA) B27 and beta(2)-microglobulin. Our goal was to investigate in vitro enteric nerve regulation and contractile activity in isolated longitudinal muscles from the jejunum and colon of HLA-B27 rats. Nontransgenic age-matched Fisher 344 rats were used as controls. Intestinal inflammation and tissue injury, quantified histologically and through tissue myeloperoxidase activity, were evident in both the jejunum and colon of HLA-B27 rats. Although resting tension and spontaneous activity of the jejunal and colonic muscles from HLA-B27 rats did not differ significantly from controls, responses to both enteric nerve stimulation or direct muscle activation were significantly inhibited. In muscles from HLA-B27 rats, electrical field stimulation (0.5 ms, 0.5-20 Hz) induced low-amplitude contractions (maximal reduction 60-65%) compared with respective controls. In the presence of atropine and guanethidine, nonadrenergic and noncholinergic contractile responses to higher frequencies of stimulation (8-20 Hz) were also of lower amplitude. These changes were accompanied by a shift in neurally mediated contractions from predominantly cholinergic in the jejunum and colon of Fisher 344 rats to predominantly nonadrenergic and noncholinergic in HLA-B27 rats. Furthermore, maximal contractions to carbachol or KCl depolarization were reduced (up to 2.7-fold) compared with respective controls. In the jejunum of HLA-B27 rats the EC(50) level for carbachol was decreased. The data indicate that gastrointestinal inflammation induced by expression of HLA-B27 is associated with hypocontractility and inhibition of enteric cholinergic control of the longitudinal muscle in both the small and large intestine.

Loss of function of Trp53, but not Apc, leads to the development of esophageal adenocarcinoma in mice with jejunoesophageal reflux

INTRODUCTION

APC and TP53 are tumor suppressor genes known to be altered frequently in human esophageal adenocarcinoma (EAC), which arises as a complication of reflux disease. To determine the functional role of these genes in the development of EAC, we have created reflux in mice gene-targeted for either Trp53 or Apc.

METHODS

Wild-type (WT), p53-knockout (Trp53-/-), or Apc-mutated (ApcMin/+) mice were generated in our breeding colony. Total gastrectomy with esophagojejunostomy was performed at 6 weeks of age, creating jejunoesophageal reflux. Unoperated control mice were maintained under identical conditions. Mice were sacrificed at 30 weeks of age. Histology of the esophagus and jejunal anastamosis or gastroesophageal junction was reviewed by a single pathologist blinded to the genotype of the animal.

RESULTS

The esophagus was normal in all of the unoperated mice (6 ApcMin/+, 6 WT, and 6 Trp53-/-). All operated mice (6 ApcMin/+, 12 WT, and 4 Trp53-/-) had esophagitis, with squamous hyperplasia and early focal ulceration. Barrett's metaplasia was identified in 33% of the operated ApcMin/+ (2/6) and 25% of the Trp53-/- (1/4) mice, but not in the WT mice. Of 4 operated Trp53-/- mice, all developed severe dysplasia of the squamous epithelium and 2 (50%) had EAC on histology, although no gross tumors were seen. No severe dysplasia or carcinoma was identified in any of the ApcMin/+ or WT mice.

CONCLUSIONS

Loss of either Trp53 or Apc leads to the development of columnar metaplasia, whereas loss of Trp53, but not Apc, leads to development of cancer in mice with jejunoesophageal reflux.

Molecular analysis of T-cell clonality in ulcerative jejunitis and enteropathy-associated T-cell lymphoma

Ulcerative jejunitis (UJ) and enteropathy-associated T-cell lymphoma (EATL) are closely related conditions both associated with celiac disease. Benign-appearing inflammatory ulcers are seen in both, which has led to the suggestion that UJ is a manifestation of EATL. The aim of this study was to investigate this relationship using the polymerase chain reaction (PCR) to detect T-cell gene rearrangement. PCR amplification of the T-cell receptor gamma-chain gene was performed on DNA extracted from lymphoma, associated inflammatory ulcers, and intervening mucosa in six EATL cases and from ulcers and intervening mucosa of seven cases of UJ. In two of these cases, DNA from a subsequent lymphoma was also studied. The PCR products from the tumor and an ulcer from one EATL case, two ulcers from one case of UJ, and one ulcer and subsequent cutaneous lymphoma from one UJ case were sequenced. Twenty-five ulcers from twelve cases of Crohn's disease, twenty sections of normal bowel, and nine celiac biopsies were included as controls. A monoclonal T-cell population defined by a dominant band equal in size to that amplified from the lymphoma was identified in at least one ulcer from four informative EATL cases and from intervening mucosa in three. Monoclonality was demonstrated in at least one, and up to thirteen, ulcers from all seven cases of UJ, in intervening mucosa in five, and in the two subsequent lymphomas. Sequencing showed the same clone was present in the tumor and the ulcer in the EATL case, in two of three ulcers from the UJ case, and in an ulcer and subsequent cutaneous lymphoma in one UJ case. All Crohn's disease ulcers and all sections of normal bowel were polyclonal. One of nine celiac biopsies showed a dominant band. In conclusion, we have shown that T-cell monoclonality is a feature of the ulcers in both UJ and EATL and that the same clone is present in EATL and its associated inflammatory ulcers and in UJ and subsequently developing lymphoma.

Studies on lipoprotein metabolism in a family with jejunal chylomicron retention

We describe two siblings with fat malabsorption and jejunal chylomicron retention. Plasma lipoproteins were studied in the patients and their first-degree relatives. The patients were a 14-year-old girl and her 8-year-old brother. Compared to healthy controls, they both had low fasting plasma concentrations of plasma total, HDL, and LDL cholesterol, as well as of apolipoproteins A-I and B. No increase in plasma lipoprotein levels or detectable apo B-48 was observed following an oral fat load. Histological studies of jejunal biopsy specimens obtained during fasting and 1 h postprandially showed severe steatosis, and an apparent block of chylomicron secretion from the endoplasmic reticulum into the Golgi apparatus was observed by electron microscopy. Liver biopsy specimens showed moderate steatosis and ultrastructural changes similar to those in the enterocytes. One healthy sister had a normal plasma lipoprotein pattern, and showed increased plasma triglyceride levels as well as the presence of apo B-48 following an oral fat load. Both parents had normal plasma total cholesterol levels, but clearly reduced fasting concentrations of HDL cholesterol and apo A-I. At least in this family, determination of plasma apo A-I levels might thus prove useful in the identification of heterozygotes.

Familial enteropathy with villous edema and immunoglobulin G2 subclass deficiency

We describe a familial form of recurrent acute, life-threatening secretory diarrhea associated with distinctive jejunal histologic changes and IgG2 subclass deficiency. Symptoms begin abruptly with anorexia and vomiting, and progress within hours to massive secretory diarrhea and shock with profound neutropenia and hypoproteinemia, including hypoalbuminemia and hypogammaglobulinemia. Affected survivors recover quickly and thereafter grow and develop normally. Biopsy specimens obtained during remission from 3 adults and 11 children show club-shaped jejunal villi broadened by edema and histiocytes with imbibed fluid; the overlying intestinal epithelium and brush border appear normal, but the basement membrane is interrupted in some areas. No characteristic microorganisms have been identified in association with the syndrome. Clinical manifestations cease in the second decade, but the abnormal jejunal histologic pattern persists into adult life. Female and male patients are equally affected, although all fatal cases have been in female subjects. Inheritance appears dominant with variable penetrance: one family member without a history of diarrhea has characteristic biopsy findings and another appears to be an obligate carrier with normal biopsy findings. Affected individuals have a reduced serum concentration of IgG2. We believe that this familial enteropathy is a unique entity, not previously described.

Familial intussusception: report of a case with recurrence in the youngest sibling and review of the literature

The etiology of idiopathic intussusception is unknown. Occurrence of intussusception in more than one patient in a same family is rare. A familial predisposition is suspected. We present a family in which the two children suffered from intussusception with recurrence in the youngest sibling and review the literature.

Chronic intestinal pseudoobstruction with myopathy and ophthalmoplegia. A muscular biochemical study of a mitochondrial disorder

The association of chronic intestinal pseudoobstruction with ophthalmoplegia has been reported previously in visceral myopathies. We report a case of this association in which muscle mitochondria had a crystalline appearance, a dense core, and decreased cytochrome c oxidase and succinate cytochrome c reductase activities. The absence of evident mitochondrial DNA deletion in the skeletal muscle of this patient does not exclude the possibility of localized deletion or mutation of mitochondrial DNA in digestive muscle.

Familial enteric neuropathy with pseudoobstruction

We report a case of autosomal dominant chronic intestinal pseudoobstruction secondary to a familial enteric neuropathy. Esophagogastrointestinal manometry studies in the index case showed decreased postprandial contractile frequency with normal amplitude of pressure activity in the stomach and small bowel. Pupillary function and autonomic reflexes were all normal, excluding an extrinsic autonomic neuropathy of the viscera. Histologic examination of the small intestine by hematoxylin and eosin stains revealed normal smooth muscles but a reduced number of neurons in the myenteric plexus without inflammatory cells or neuroNal intranuclear inclusions. Histologic examination of the myenteric plexus using the sections taken along the longitudinal axis of the intestine, stained with silver by the Smith technique, disclosed decreased numbers of argyrophilic neurons and degeneration of neurons and axons; however, there was no reactive increase in the number of glial cell nuclei. The patient's mother had suffered from chronic intestinal pseudoobstruction, which did not abate following extensive small bowel resection. This is the third family reported with an autosomal dominant enteric neuropathy unassociated with evidence of extrinsic autonomic or peripheral neuropathy. Subtotal resection of the small bowel was followed by recurrence of the pseudoobstruction syndrome in both affected members of the family.

Is adult-onset coeliac disease due to a low-grade lymphoma of intraepithelial T lymphocytes?

Enteropathy-associated T-cell lymphoma commonly presents with malabsorption, and debate continues as to whether adult-onset coeliac disease (CD) is itself a form of low-grade lymphoma. A 59-year-old man with adult-onset CD required resection of a segment of oedematous jejunum. Histological examination of this tissue revealed an intense intraepithelial lymphocytosis. Immunophenotypic (CD3-, CD4-, CD8-, CD34-, and CD45 RO-) and cytogenetic (deletion of the Y chromosome and chromosome 9) abnormalities were found, together with monoclonal T-cell-receptor gene rearrangements. Some patients with adult-onset CD may have low-grade lymphoma from the outset of their illness.

Jejunal diverticulosis in a family

The presence of small intestinal diverticula was examined in a family of eight siblings. Six of the siblings had diverticula of the duodenum and/or the jejunoileal tract. Three of them had multiple jejunoileal diverticula, one had two jejunal diverticula, and two had duodenal diverticula. In addition, diseases of an immunologic nature were present in four of the siblings (rheumatoid arthritis, ulcerative colitis, myxoedema following thyroiditis, and non-viral hepatitis).

Autopsy findings in two adult siblings with Coffin-Lowry syndrome

We describe the major autopsy findings in two adult sibs of the original pedigree of Lowry et al [Am J Dis Child 121:496-500, 1971]. These results support the idea that Coffin-Lowry syndrome is a systemic connective tissue disorder. Visceral neuropathy was also noted as the basis of extensive intestinal diverticular disease.

Peutz-Jeghers syndrome in children: report of two cases and review of the literature

In this article, we report two new cases of Peutz-Jeghers syndrome in children and review the literature over the past twenty years. This series of 70 cases demonstrates that the clinical pictures observed in children are similar to those of adults. Rectal prolapse or extrusion of polyps can be the clue to the diagnosis at an early age, even in the absence of pigmentation, which can appear later. Gastroduodenal polyps were strikingly frequent in the less than or equal to 16-yr-old group (62%) a circumstance that can create operative difficulties. Five out of the 70 patients (7.14%) had tumors during childhood (two gastrointestinal adenocarcinomas, two ovarian and one testicular neoplasms). A higher risk of tumor development in these patients does exist either as a result of degeneration of the polyps or of a genetic predisposition. Whenever operation becomes necessary, a very cautious approach must be advised in order to preserve as much intestinal length as possible in these patients, who have a lifelong disease which may require repeated operations.

Familial pericentric inversion of chromosome 2

A pericentric inversion of chromosome 2 was detected in eight members of a family ascertained via a proband with congenital jejunal atresia born of consanguineous parents. The latter affection was also present in one of his sibs. Microdensitometric analysis of the patterns of G bands of the inverted segment revealed a balanced rearrangement with unusual break points in p12 and q36; the association with the disease is apparently coincidental.