Clinicopathologic features of chronic nonspecific multiple ulcers of the small intestine

Indolent T-cell Lymphoproliferative Disorder of the Gastrointestinal Tract Mimicking Crohn's Disease

Indolent clonal T-cell lymphoproliferative disorder (iCTLD-GI)/indolent T-cell lymphoma of the gastrointestinal tract (iTLP-GI) poses diagnostic challenges, and despite its rarity, accurate diagnosis is crucial for appropriate management. We report the case of 34-year-old female with a 19-year history of gastrointestinal symptoms suggestive of inflammatory bowel disease (IBD). Subsequent evaluation revealed iCTLD-GI/iTLP-GI with extensive Crohn's disease-like morphological alterations, previously unreported. These macroscopic and microscopic aspects underscore the need for a comprehensive evaluation to avoid misdiagnosis with IBD. Additionally, molecular studies have identified potential therapeutic targets, highlighting the evolving management strategies. This case underscores the diagnostic complexity of iCTLD-GI/iTLP-GI, especially when the condition mimicks IBD such as Crohn's disease.

First case report of dichorionic diamniotic twins with chronic enteropathy associated with the SLCO2A1 gene

We report the case of twins diagnosed with chronic enteropathy associated with the SLCO2A1 gene (CEAS) based on characteristic ulcer findings, which required 8 years to diagnose. Both twins had similar symptoms, including anemia and growth failure but the gastrointestinal tract was not evaluated initially because of mild symptoms that were considered consistent with psychological etiology. The endoscopic findings of the firstborn child showed spiral ulcer scars and pseudodiverticulum formation without Helicobacter pylori infection or eosinophilic infiltration in the duodenum. Since the twins presented with ulcers of an unknown cause simultaneously and the first-born child had a spiral ulcer, CEAS was suspected. Genetic analysis and high levels of prostaglandin E major urinary metabolites in the urine led to a definitive diagnosis of CEAS.

A rare case of bleeding jejunal ulcer diagnosed by intraoperative use of enteroscopy

INTRODUCTION

Small bowel bleeding can be overt or occult. Despite advances in imaging and endoscopy, the diagnosis and treatment of small bowel bleeding remain challenging due to its length and location. Diagnostic procedures such as push enteroscopy, capsule endoscopy and intraoperative enteroscopy are recommended to identify the source of bleeding.

CASE PRESENTATION

A 33-year-old female with no prior history of bleeding diathesis presented with massive lower GI bleeding. Although she was in hypovolemic shock from bleeding, physical exam, splanchnic angiography and colonoscopy were unable to localize the source of bleeding. The patient continued to bleed and deteriorate despite transfusions. Exploratory laparotomy was done but localizing the source with manual palpation of small bowel was difficult. Intraoperative enteroscopy was done and showed a 2 by 1 cm ulcerative lesion at mid jejunum. Part of jejunum containing the ulcer was resected and anastomosis done. The patient did well postoperatively and on follow up.

CLINICAL DISCUSSION

A bleeding primary jejunal ulcer is rare clinical scenario difficult to diagnose. Intraoperative enteroscopy is useful in cases where initial diagnostic workups are inconclusive. It can be performed using various types of endoscopes, such as a standard or pediatric colonoscope, push enteroscope, or a sonde enteroscope, during laparotomy.

CONCLUSION

Primary jejunal ulcer is a rare cause of massive lower GI bleeding. Although minimally invasive deep endoscopic techniques to diagnose small bowel ulcers are evolving, intraoperative enteroscopy remains to be technically easy and helpful tool to make a diagnosis and guide intervention especially in a patient undergoing laparotomy for bleeding small bowel ulcer.

A Novel Chronic Enteropathy Associated with SLCO2A1 Gene Mutation: Enterography Findings in a Multicenter Korean Registry

OBJECTIVE

Chronic enteropathy associated with SLCO2A1 gene (CEAS) is a recently recognized disease. We aimed to evaluate the enterographic findings of CEAS.

MATERIALS AND METHODS

Altogether, 14 patients with CEAS were confirmed based on known SLCO2A1 mutations. They were registered in a multicenter Korean registry between July 2018 and July 2021. Nine of the patients (37.2 ± 13 years; all female) who underwent surgery-naïve-state computed tomography enterography (CTE) or magnetic resonance enterography (MRE) were identified. Two experienced radiologists reviewed 25 and 2 sets of CTE and MRE examinations, respectively, regarding the small bowel findings.

RESULTS

In initial evaluation, eight patients showed a total of 37 areas with mural abnormalities in the ileum on CTE, including 1-4 segments in six and > 10 segments in two patients. One patient showed unremarkable CTE. The involved segments were 10-85 mm (median, 20 mm) in length, 3-14 mm (median, 7 mm) in mural thickness, circumferential in 86.5% (32/37), and showed stratified enhancement in the enteric and portal phases in 91.9% (34/37) and 81.8% (9/11), respectively. Perienteric infiltration and prominent vasa recta were noted in 2.7% (1/37) and 13.5% (5/37), respectively. Bowel strictures were identified in six patients (66.7%), with a maximum upstream diameter of 31-48 mm. Two patients underwent surgery for strictures immediately after the initial enterography. Follow-up CTE and MRE in the remaining patients showed minimal-to-mild changes in the extent and thickness of the mural involvement for 17-138 months (median, 47.5 months) after initial enterography. Two patients required surgery for bowel stricture at 19 and 38 months of follow-up, respectively.

CONCLUSION

CEAS of the small bowel typically manifested on enterography in varying numbers and lengths of abnormal ileal segments that showed circumferential mural thickening with layered enhancement without perienteric abnormalities. The lesions caused bowel strictures that required surgery in some patients.

Chronic enteropathy associated with SLCO2A1 gene and hereditary fructose intolerance: A coincidence of two rare diseases

Chronic enteropathy associated with SLCO2A1 gene (CEAS) is a rare disorder characterized by multiple small intestine ulcers. Patients with CEAS typically present with chronic anemia and gastrointestinal bleeding. Besides CEAS, SLCO2A1 mutations cause primary hypertrophic osteoarthropathy (PHO) which is considered as an extraintestinal manifestation in CEAS patients. Since CEAS and Crohn's disease are clinically indistinguishable, patients are often misdiagnosed with Crohn's disease. Herein, we describe a 4-year-old Turkish girl with CEAS due to homozygous pathogenic variant (c.656C > T) in SLCO2A1 with concomitant hereditary fructose intolerance (HFI) caused by homozygous pathogenic variant (c.1005C > G) in ALDOB. Prompt restriction of fructose, sucrose and sorbitol resulted in hepatomegaly regression and mild amelioration of patient's symptoms. Despite budesonide and azathioprine treatments, patient's protein losing enteropathy and chronic anemia did not improve. Although previous CEAS cases were reported from East Asian countries, it is likely to occur in people from other geographic areas. CEAS seems to be underdiagnosed and high index of suspicion is required for the diagnosis of this rare entity. Patients with prior diagnosis of Crohn's disease with no response to immunosuppressive treatment or anti-TNF therapy should be re-evaluated for possible CEAS diagnosis.

Chronic Enteropathy Associated with Solute Carrier Organic Anion Transporter Family, Member 2A1 (SLCO2A1) with Positive Immunohistochemistry for SLCO2A1 Protein

Chronic enteropathy associated with solute carrier organic anion transporter family, member 2A1 (SLCO2A1) (CEAS) is a rare autosomal recessive hereditary disease characterized by chronic persistent anemia and hypoproteinemia. Its diagnosis typically requires a genetic analysis. The efficacy of immunohistochemical staining with SLCO2A1 polyclonal antibody as a pre-diagnostic tool for CEAS has been previously reported. We herein report a patient with CEAS in whom immunohistochemical staining confirmed SLCO2A1 protein expression. The immunopositive results may have been due to nonsense-mediated RNA decay. As immunohistochemical staining of SLCO2A1 protein may show immunopositive results, a genetic analysis should also be performed when CEAS is strongly clinically suspected.

Cryptogenic multifocal ulcerating stenosing enteritis and other under-recognised small bowel inflammatory enteropathies

PURPOSE OF REVIEW

Capsule endoscopy and more sensitive radiological techniques have resulted in more enteropathies being detected. A rare disease of unknown aetiology, 'cryptogenic multifocal ulcerating stenosing enteritis' or 'chronic nonspecific multiple ulcers of the small intestine' (CNSU), has long been recognised. This review aims to describe how disease can be better diagnosed and differentiated from other small bowel inflammatory disorders.

RECENT FINDINGS

Genetic studies have shown that some patients with CNSU (the term used in Japanese studies) express SLCO2A1 gene mutations, a gene which encodes a prostaglandin transporter expressed on vascular endothelium, allowing a more specific diagnosis of 'chronic enteropathy associated with SLCO2A1'. Mutations in the PLA2G4A gene result in cytosolic phospholipase A2α deficiency and reduced arachidonic acid for prostaglandin synthesis leading to a severe ulcerating, stenosing and fistulating small bowel disease.

SUMMARY

A 'prostaglandin-related enteropathy' should be considered in patients with atypical small bowel ulceration and stenosis. Genetic analysis will allow the detection of SLCO2A1 and PLA2G4A gene mutations. However, a careful history of medication use and a urinary metabolite screen may reveal the use of nonsteroidal anti-inflammatory drugs, a common cause of small bowel injury which is well recognised as being mediated by prostaglandin inhibition.

Four Variants of SLCO2A1 Identified in Three Chinese Patients with Chronic Enteropathy Associated with the SLCO2A1 Gene

BACKGROUND

Chronic enteropathy associated with the SLCO2A1 gene (CEAS) is an enteropathy characterized by multiple small intestinal ulcers of nonspecific histology, also known as chronic nonspecific multiple ulcers of the small intestine. The SLCO2A1 gene encodes a prostaglandin transporter (PGT).

AIMS

The aim of this study was to investigate the clinical characteristics of ten Chinese patients with intestinal ulcers of unknown origin, screen them for variants of SLCO2A1, and to investigate the expression of PGT in the small intestinal mucosa of patients with CEAS.

METHODS

Ten Chinese patients with intestinal ulcers of unknown origin were included in this study. Blood samples were collected for whole-exome sequencing and Sanger sequencing of candidate gene variants. Immunohistochemical staining was used to investigate the expression of PGT.

RESULTS

These ten patients were clinically diagnosed with intestinal ulcers of unknown origin based on criteria established according to earlier publications. Three of them were genetically diagnosed as having CEAS and four candidate variants of the SLCO2A1 gene were identified, among which c.941-1G>A, c.178G>A and c.1681C>T were detected in patients with CEAS for the first time. The terminal ileum was involved in all three patients with CEAS in our study, which was different from the results of Japanese patients. The expression of PGT in the vascular endothelial cells of the intestinal mucosa tissues of patients with CEAS was negative or intermediate.

CONCLUSION

We summarized the clinical data of ten Chinese patients with intestinal ulcers of unknown origin and identified three novel SLCO2A1 variants from three patients with CEAS. This study improves our understanding of CEAS and broadens the spectrum of SLCO2A1 variants known to cause CEAS.

Recent advances in studies of SLCO2A1 as a key regulator of the delivery of prostaglandins to their sites of action

Solute carrier organic anion transporter family member 2A1 (SLCO2A1, also known as PGT, OATP2A1, PHOAR2, or SLC21A2) is a plasma membrane transporter consisting of 12 transmembrane domains. It is ubiquitously expressed in tissues, and mediates the membrane transport of prostaglandins (PGs, mainly PGE₂, PGF_2α, PGD₂) and thromboxanes (e.g., TxB₂). SLCO2A1-mediated transport is electrogenic and is facilitated by an outwardly directed gradient of lactate. PGs imported by SLCO2A1 are rapidly oxidized by cytoplasmic 15-hydroxyprostaglandin dehydrogenase (15-PGDH, encoded by HPGD). Accumulated evidence suggests that SLCO2A1 plays critical roles in many physiological processes in mammals, and it is considered a potential pharmacological target for diabetic foot ulcer treatment, antipyresis, and non-hormonal contraception. Furthermore, whole-exome analyses suggest that recessive inheritance of SLCO2A1 mutations is associated with two refractory diseases, primary hypertrophic osteoarthropathy (PHO) and chronic enteropathy associated with SLCO2A1 (CEAS). Intriguingly, SLCO2A1 is also a key component of the Maxi-Cl channel, which regulates fluxes of inorganic and organic anions, including ATP. Further study of the bimodal function of SLCO2A1 as a transporter and ion channel is expected to throw new light on the complex pathology of human diseases. Here, we review and summarize recent information on the molecular functions of SLCO2A1, and we discuss its pathophysiological significance.

Chronic Enteropathy Associated with SLCO2A1 with Pachydermoperiostosis

A 49-year-old man complained of chronic palpitation and shortness of breath, which had recently become exacerbated. A blood examination indicated severe refractory anemia and hypoproteinemia. Physical examinations revealed anemia, a systolic murmur, and spoon nails. Multiple nonspecific ileal ulcers were observed. A pathological examination indicated a small granuloma with CD68-positive histiocytes. He had a deeply wrinkled forehead, chiseled face, and clubbed fingers. Radiography revealed periostosis of the fingers and long bones in the limb. He was diagnosed with pachydermoperiostosis. SLCO2A1 demonstrated a c.1807C>T homo-mutation. He was also diagnosed with SLCO2A1-associated chronic enteropathy and thus was treated with 5-aminosalicylic acid, which temporarily improved the ileal ulcers, anemia, and hypoalbuminemia.

A case report of intestinal obstruction caused by cryptogenic multifocal ulcerous stenosing enteritis

Background

Cryptogenic multifocal ulcer stenosing enteritis (CMUSE) is a rare disease characterized by multiple superficial ulcers, stenosis, and obstruction of the small intestine of unknown origin, and the course can recur.

Case presentation

We encountered a 62-year-old male patient with intestinal obstruction. The patient was admitted to the hospital for surgical treatment due to intestinal obstruction, and was diagnosed with cryptogenic multifocal ulcer stenosis enteritis due to comprehensive surgery and postoperative pathological considerations.

Conclusion

In the future, we will continue to follow up the patient. The present study aims to remind clinicians of this disease, and reduce the incidence of misdiagnosis.

Epstein-Barr virus-associated enteritis with multiple ulcers: The first autopsy case

Epstein-Barr virus (EBV)-associated enteritis is extremely rare and has not been well characterized. Herein, we present the first autopsy case of EBV-associated enteritis with multiple ulcers in a 73-year-old Japanese male. The patient had abdominal pain and was clinically diagnosed with enteritis. An endoscopic examination revealed multiple ulcers at the terminal ileum. His condition worsened due to serosanguinous bowel discharge and the patient was then admitted to the hospital. Ileocecal and subtotal small intestinal resection was performed for repetitive hemorrhage from ulcers. However, the patient died due to uncontrolled hemorrhage. An autopsy was then performed in order to explore the cause of ulcers in the small intestine. Macroscopic findings revealed multiple ulcers with occasional cobblestone-like appearance of the ileum. Histological analysis revealed marked infiltration of lymphocytes and plasma cells around the ulcer. EBV-encoded RNA in situ hybridization (EBER-ISH) revealed positive inflammatory cells. Cytomegalovirus was immunohistochemically negative. Macroscopic and microscopic findings obtained from autopsy specimens showed no foci of inflammation and EBER-ISH-positive stromal cells in the esophagus, stomach, and colorectum. EBV-associated enteritis can cause uncontrolled repetitive hemorrhage from ulcers and result in critical condition of the patient, which can be used for differential diagnosis.

Fatal course of idiopathic chronic ulcerative enteritis with panenteritis and perforation: a case report and review of literature

BACKGROUND

Idiopathic chronic ulcerative enteritis (ICUE) is a very rare disease with high mortality. Because of clinical rarity, several small case reports have been published and there is a lack of large sample study. Preoperative definite diagnosis is difficult. Although definite treatment for ICUE is radical surgical resection, surgical decision in operative field is difficult.

CASE PRESENTATION

A 77-year-old man came to the emergency department with complaints of a 1-day history of abdominal pain and abdominal distension. Abdominal computed tomography revealed ileus and focal free air. Laparotomy revealed multiple small bowel tiny perforations in the ileum. The serosa surface in the whole small bowel had small multiple yellowish tiny discolored lesions. Despite the presence of multiple mucosal ulcers in entire small bowel, the ileum including perforation site was resected segmentally. Microscopically, mucosal ulcers in resected small bowel demonstrated transmural inflammation, no granuloma, and no lymphoid aggregates. These features were consistent with a diagnosis of ICUE with panenteritis and perforation. After surgery, the patient's general condition gradually aggravated. Unfortunately, the patient died of multiple organ failure on post-operative day 14.

CONCLUSION

Surgically, the decision including resection range, anastomosis or enterotomy becomes difficult in ICUE with panenteritis. According to recent 40 year's revised data, the post-operative mortality of ICUE is about 53.4%. Although ICUE is rare, its recognition is important for appropriate diagnosis and treatment. Retrospective multicenter case studies are required to determine proper treatment and improve prognosis.

Chronic enteropathy associated with SLCO2A1 gene: A case report and literature review

A case of chronic enteropathy associated with SLCO2A1 gene (CEAS) is presented. The female patient was readmitted four times during a three-year follow-up period for intractable dropsy and anemia. Multiple ulcers of small bowel wall were revealed by endoscopic examination. Computed tomography enterography (CTE) and magnetic resonance enterography (MRE) showed the segmental wall thickening of the small bowel. Hepatosplenomegaly and increased bone density of spine and pelvis suggested the diagnosis of myelofibrosis. X-ray films showed the cortical thickening of tibiofibula. The mutations of SLCO2A1 gene were revealed by gene test and the diagnosis of CEAS was confirmed. According to our case report, imaging examinations, including CTE, MRE and X-ray films provide additional valuable information during the diagnostic procedure of CEAS.

Cryptogenic Multifocal Ulcerating Stenosing Enteropathy(CMUSE) and/or Chronic Non-specific Multiple Ulcers of the Small Intestine(CNSU) and Non-granulomatous Ulcerating Jejunoileitis (NGUJI)

PURPOSE OF REVIEW

The purpose is to make aware of the existence of the rare and exclusive small intestine (SI) diseases, namely cryptogenic multifocal ulcerating stenosing enteropathy (CMUSE) or chronic non-specific multiple ulcers of the small intestine (CNSU) and non-granulomatous ulcerating jejunoileitis (NGUJI). The article will elucidate their epidemiology, pathogenesis, clinical features, diagnosis, differentiating features and management.

RECENT FINDINGS

Recent papers have published the clinical features and diagnostic criteria of CMUSE/CNSU and NGUJI. CNSU/CMUSE is caused by gene mutations involved in the prostaglandin pathways. Although capsule endoscopy can detect these lesions, it carries a risk of retention. TNF antagonists and azathioprine have shown response in few cases. CMUSE/CNSU and NGUJI are uncommon diseases that cause relapsing SI obstruction and bleed due to short-segment strictures and multiple shallow ulcers. This article focuses on current knowledge and novel insights regarding their pathogenesis, genetics, clinical features, diagnostic criteria and management. Multicentric clinical and genetic studies are the need of the hour.

Distinction between Chronic Enteropathy Associated with the SLCO2A1 Gene and Crohn's Disease

Background/Aims

We recently identified recessive mutations in the solute carrier organic anion transporter family member 2A1 gene (SLCO2A1) as causative variants of chronic nonspecific multiple ulcers of the small intestine (chronic enteropathy associated with SLCO2A1, CEAS). The aim of this study was to investigate the gastroduodenal expression of the SLCO2A1 protein in patients with CEAS and Crohn’s disease (CD).

Methods

Immunohistochemical staining for SLCO2A1 was performed with a polyclonal antibody, HPA013742, on gastroduodenal tissues obtained by endoscopic biopsy from four patients with CEAS and 29 patients with CD.

Results

The expression of SLCO2A1 was observed in one of four patients (25%) with CEAS and in all 29 patients (100%) with CD (p<0.001). The three patients with CEAS without SLCO2A1 expression had a homozygous splice-site mutation in SLCO2A1, c.1461+1G>C (exon 7) or c.940+1G>A (exon 10). The remaining one CEAS patient with positive expression of SLCO2A1 had compound heterozygous c.664G>A and c.1807C>T mutations.

Conclusions

Immunohistochemical staining for SLCO2A1 in gastroduodenal tissues obtained by endoscopic biopsy is considered useful for the distinction of CEAS from CD.

Measurement of prostaglandin metabolites is useful in diagnosis of small bowel ulcerations

BACKGROUND

We recently reported on a hereditary enteropathy associated with a gene encoding a prostaglandin transporter and referred to as chronic enteropathy associated with SLCO2A1 gene (CEAS). Crohn's disease (CD) is a major differential diagnosis of CEAS, because these diseases share some clinical features. Therefore, there is a need to develop a convenient screening test to distinguish CEAS from CD.

AIM

To examine whether prostaglandin E major urinary metabolites (PGE-MUM) can serve as a biomarker to distinguish CEAS from CD.

METHODS

This was a transactional study of 20 patients with CEAS and 98 patients with CD. CEAS was diagnosed by the confirmation of homozygous or compound heterozygous mutation of SLCO2A1. We measured the concentration of PGE-MUM in spot urine by radioimmunoassay, and the concentration was compared between the two groups of patients. We also determined the optimal cut-off value of PGE-MUM to distinguish CEAS from CD by receiver operating characteristic (ROC) curve analysis.

RESULTS

Twenty Japanese patients with CEAS and 98 patients with CD were enrolled. PGE-MUM concentration in patients with CEAS was significantly higher than that in patients with CD (median 102.7 vs 27.9 μg/g × Cre, P < 0.0001). One log unit increase in PGE-MUM contributed to 7.3 increase in the likelihood for the diagnosis of CEAS [95% confidence interval (CI) 3.2-16.7]. A logistic regression analysis revealed that the association was significant even after adjusting confounding factors (adjusted odds ratio 29.6, 95%CI 4.7-185.7). ROC curve analysis revealed the optimal PGE-MUM cut-off value for the distinction of CEAS from CD to be 48.9 μg/g × Cre with 95.0% sensitivity and 79.6% specificity.

CONCLUSION

PGE-MUM measurement is a convenient, non-invasive and useful test for the distinction of CEAS from CD.

Clinical features of chronic enteropathy associated with SLCO2A1 gene: a new entity clinically distinct from Crohn's disease

BACKGROUND

Chronic enteropathy associated with SLCO2A1 gene (CEAS) is a hereditary disease caused by mutations in the SLCO2A1 gene and characterized by multiple small intestinal ulcers of nonspecific histology. SLCO2A1 is also a causal gene of primary hypertrophic osteoarthropathy (PHO). However, little is known about the clinical features of CEAS or PHO.

METHODS

Sixty-five Japanese patients recruited by a nationwide survey of CEAS during 2012-2016 were enrolled in this present study. We reviewed the clinical information of the genetically confirmed CEAS patients.

RESULTS

We identified recessive SLCO2A1 mutations at 11 sites in 46 patients. Among the 46 patients genetically confirmed as CEAS, 13 were men and 33 were women. The median age at disease onset was 16.5 years, and parental consanguinity was present in 13 patients (28%). Anemia was present in 45 patients (98%), while a single patient experienced gross hematochezia. All patients showed relatively low inflammatory markers in blood tests (median CRP 0.20 mg/dl). The most frequently involved gastrointestinal site was the ileum (98%), although no patient had mucosal injuries in the terminal ileum. Mild digital clubbing or periostosis was found in 13 patients (28%), with five male patients fulfilling the major diagnostic criteria of PHO.

CONCLUSIONS

The clinical features of CEAS are distinct from those of Crohn's disease. Genetic analysis of the SLCO2A1 gene is therefore recommended in patients clinically suspected of having CEAS.

Genetic analysis is helpful for the diagnosis of small bowel ulceration

The widespread use of capsule endoscopy and balloon-assisted endoscopy has provided easy access for detailed mucosal assessment of the small intestine. However, the diagnosis of rare small bowel diseases, such as cryptogenic multifocal ulcerous stenosing enteritis (CMUSE), remains difficult because clinical and morphological features of these diseases are obscure even for gastroenterologists. In an issue of this journal in 2017, Hwang et al reviewed and summarized clinical and radiographic features of 20 patients with an established diagnosis of CMUSE. Recently, recessive mutations in the PLA2G4A and SLCO2A1 genes have been shown to cause small intestinal diseases. The small bowel ulcers in each disease mimic those in the other and furthermore those found in nonsteroidal anti-inflammatory drug-induced enteropathy. These recent and novel findings suggest that a clinical diagnosis exclusively based on the characteristics of small bowel lesions is possibly imprecise. Genetic analyses seem to be inevitable for the diagnosis of rare small bowel disorders such as CMUSE.

Immunohistochemical differentiation between chronic enteropathy associated with SLCO2A1 gene and other inflammatory bowel diseases

Background/Aims

We recently identified recessive mutations in the solute carrier organic anion transporter family member 2A1 gene (SLCO2A1) as causative variants of chronic enteropathy associated with SLCO2A1 (CEAS). The aim of this study was to evaluate SLCO2A1 protein expression in the intestinal tissues of patients with CEAS, intestinal Behçet's disease (BD), simple ulcer (SU), and Crohn's disease (CD).

Methods

Immunohistochemical staining using a polyclonal anti-SLCO2A1 antibody was performed on the resected intestinal specimens from 13 cases of CD, 9 cases of intestinal BD/SU, and 3 cases of CEAS. The extent of SLCO2A1 expression was determined by counting positively-staining vascular endothelial cells and scored as 0 (no cells), 1 (1%–30% cells), 2 (31%–60%), or 3 (>60%). The intensity of SLCO2A1 expression was scored either as 0 (negative), 1 (intermediate), or 2 (strong). The extent score and intensity score were summed for the final score of 0, 2, 3, 4, or 5.

Results

SLCO2A1 protein expression was observed in 1 of 3 cases of CEAS (33%), all 13 cases of CD (100%), and all 9 cases of BD/SU (100%). The mean final expression scores of CEAS, CD, and BD/SU were 1.6 (range, 0–5), 4.8 (range, 4–5), and 4.3 (range, 4–5), respectively. The final expression score in CEAS was significantly lower than in CD (P=0.03).

Conclusions

Immunohistochemical staining of the SLCO2A1 protein is considered useful to distinguish CEAS from other inflammatory bowel diseases.

A rare cause of multiple small bowel ulcers and strictures in a 10-year-old child

Enteritis and small bowel ulcers can be caused by inflammatory bowel disease, drug-induced enteritis, cytomegalovirus, tuberculosis, or intestinal lymphoma. Cryptogenic multifocal ulcerous stenosing enteritis (CMUSE) is an uncommon idiopathic cause of ulceration and stricture of the small bowel. CMUSE can occur in adults, but only few pediatric cases have been reported. Inflammatory bowel disease and other causes should be carefully sought first before the diagnosis of CMUSE can be made. Previous reports demonstrated that surgical intervention may be necessary for both diagnostic and therapeutic purposes. With regard to the management, systemic corticosteroids may help, and surgery plays a role in patients present with signs of intestinal obstruction. We report a young girl who presented with a prolonged history of refractory iron deficiency anemia with protein-losing enteropathy without other obvious gastrointestinal symptoms. She underwent several laboratory and endoscopic investigations as well as histopathology of the resected full-thickness small bowel area before a proposed diagnosis of CMUSE was made. A trial of immunosuppression (both prednisolone and azathioprine) was initiated that provided a relatively satisfactory result.

Roles of Organic Anion Transporting Polypeptide 2A1 (OATP2A1/SLCO2A1) in Regulating the Pathophysiological Actions of Prostaglandins

Solute carrier organic anion transporter family member 2A1 (OATP2A1, encoded by the SLCO2A1 gene), which was initially identified as prostaglandin transporter (PGT), is expressed ubiquitously in tissues and mediates the distribution of prostanoids, such as PGE₂, PGF_2α, PGD₂ and TxB₂. It is well known to play a key role in the metabolic clearance of prostaglandins, which are taken up into the cell by OATP2A1 and then oxidatively inactivated by 15-ketoprostaglandin dehydrogenase (encoded by HPGD); indeed, OATP2A1-mediated uptake is the rate-limiting step of PGE₂ catabolism. Consequently, since OATP2A1 activity is required for termination of prostaglandin signaling via prostanoid receptors, its inhibition can enhance such signaling. On the other hand, OATP2A1 can also function as an organic anion exchanger, mediating efflux of prostaglandins in exchange for import of anions such as lactate, and in this context, it plays a role in the release of newly synthesized prostaglandins from cells. These different functions likely operate in different compartments within the cell. OATP2A1 is reported to function at cytoplasmic vesicle/organelle membranes. As a regulator of the levels of physiologically active prostaglandins, OATP2A1 is implicated in diverse physiological and pathophysiological processes in many organs. Recently, whole exome analysis has revealed that recessive mutations in SLCO2A1 cause refractory diseases in humans, including primary hypertrophic osteoarthropathy (PHO) and chronic non-specific ulcers in small intestine (CNSU). Here, we review and summarize recent information on the molecular functions of OATP2A1 and on its physiological and pathological significance.

Chronic Enteropathy Associated With SLCO2A1 Gene [CEAS]-Characterisation of an Enteric Disorder to be Considered in the Differential Diagnosis of Crohn's Disease

Small intestinal ulcers include mucosal damage caused by drugs, particularly nonsteroidal anti-inflammatory drugs [NSAIDs], infectious diseases, and idiopathic inflammatory bowel disease. Previously, a group of Japanese investigators reported an unusual and uncommon type of enteritis and referred to the condition as chronic nonspecific multiple ulcers of the small intestine [CNSU]. CNSU is characterised by chronic blood and protein loss through persistent small intestinal ulcers. Recently, four candidate mutations in the solute carrier organic anion transporter family, member 2A1 [SLCO2A1] gene, encoding a prostaglandin transporter, were identified by whole-exome sequencing in patients with CNSU. However, because the name 'CNSU' was somewhat ambiguous, the more appropriate nomenclature of 'chronic enteropathy associated with the SLCO2A1 gene' [CEAS] has been suggested. CEAS ulcers are characterised by multiple, circular or eccentric oblique, shallow lesions with discrete margins. The most frequently affected site of CEAS is the ileum, in contrast to 'cryptogenic multifocal ulcerous stenosing enteritis [CMUSE]', for which the most frequent site is the jejunum. Impaired prostaglandin utilisation is thought to cause the small intestinal mucosal damage observed in CEAS, CMUSE, and NSAID-induced enteropathy. This review article focuses on endoscopic and clinical features of genetically diagnosed CEAS, accumulated in a nationwide survey, and illustrates the observations in the format of an atlas.

Pediatric-onset Chronic Nonspecific Multiple Ulcers of Small Intestine: A Nationwide Survey and Genetic Study in Japan

We performed a Japanese nationwide survey of pediatric-onset chronic nonspecific multiple ulcers of the small intestine between January 2000 and July 2013 in 176 institutions of pediatric surgery or pediatric gastroenterology and clarified the clinical features associated with genetic abnormalities in the Solute Carrier Organic Anion Transporter Family, Member 2A1 (SLCO2A1) gene. A total of 4 cases (3 girls and 1 boy) were diagnosed in this series, which had to be differentiated from Crohn disease, Behçet disease, tuberculosis, or drug-induced enteropathy. Clinical symptoms appeared in infants and accurate diagnosis required several years. Medical therapies for inflammatory bowel disease were administered in all patients; however, 2 of the 4 patients had mutation in the SLCO2A1 gene which are responsible for primary hypertrophic osteoarthopathy, and underwent strictureplasty or ileal resection after long-term follow-up. Pediatric gastroenterologists should include this new entity in the differential diagnosis of small intestinal ulcers and inflammatory bowel disease.