Immune-mediated enteropathies: From bench to bedside

Paediatric Congenital Enteropathies: Clinical and Histological Review

Paediatric congenital enteropathies (PCEs) are a group of rare inherited diseases with a typical early onset in life. Prompt identification and treatment are crucial to avoid potentially fatal consequences. This review aims to provide a paradigmatic framework for clinical and histological identification of PCEs, with an emphasis on congenital conditions involving epithelial shape, trafficking and polarity, enteroendocrine function, immunomodulatory diseases, and extremely early onset inflammatory bowel illness. A proper classification is founded on histopathological characteristics and clinical parameters (such as consanguinity, anomalies in amniotic fluid, prenatal expression or early neonatal onset, stool appearance, persistence of symptoms despite fasting, and extra-intestinal manifestations, etc.). The increasing accessibility and convenience of genetic tests has also accelerated the identification of genes related to specific phenotypes of PCEs, improving the diagnostic and care pathway. As a "niche" pathology, PCEs are susceptible to misdiagnosis due to a limited awareness of these entities, and their identification requires extensive training and specialized facilities. The aim of our review is to emphasize the importance of an integrated approach, combining clinical, histological, and molecular analysis, to achieve a definitive diagnosis and guide the treatment.

Successful Long-Term Treatment of Collagenous Sprue With Tacrolimus in a 25-Year-Old With Severe Intestinal Failure

A 25-year-old male presented with chronic watery diarrhea and severe intestinal failure due to collagenous sprue. Treatments, including immunosuppressants and a gluten-free diet, were ineffective. Tacrolimus shows promise in treating refractory cases.

Histopathology underlying environmental enteric dysfunction in a cohort study of undernourished children in Bangladesh, Pakistan, and Zambia compared with United States children

BACKGROUND

Environmental enteric dysfunction (EED) is an asymptomatic intestinal disorder associated with growth impairment, delayed neurocognitive development, and impaired oral vaccine responses.

OBJECTIVES

We set out to develop and validate a histopathologic scoring system on duodenal biopsies from a cohort study of children with growth failure in Bangladesh, Pakistan, and Zambia ("EED") with reference to biopsies from United States children with no clinically reported histologic pathology (referred to hereafter as "normal") or celiac disease.

METHODS

Five gastrointestinal pathologists evaluated 745 hematoxylin and eosin slide images from 291 children with EED (mean age: 1.6 y) and 66 United States children (mean age: 6.8 y). Histomorphologic features (i.e., villus/crypt architecture, goblet cells, epithelial and lamina propria acute/chronic inflammation, Brunner's glands, Paneth cells, epithelial detachment, enterocyte injury, and foveolar metaplasia) were used to score each histopathologic slide. Generalized estimating equations were used to determine differences between EED, normal, and celiac disease, and receiver operating characteristic curves were used to assess predictive value.

RESULTS

Biopsies from the duodenal bulb showed higher intramucosal Brunner's gland scores and lower intraepithelial lymphocyte scores than from the second or third parts of the duodenum (D2/3), so only D2/3 were included in the final analysis. Although 7 parameters differed significantly between EED and normal biopsies in regression models, only 5 (blunted villus architecture, increased intraepithelial lymphocytosis, goblet cell depletion, Paneth cell depletion, and reduced intramucosal Brunner's glands) were required to create a total score percentage (TSP-5) that correctly identified EED against normal biopsies (AUC: 0.992; 95% CI: 0.983, 0.998). Geographic comparisons showed more severe goblet cell depletion in Bangladesh and more marked intraepithelial lymphocytosis in Pakistan.

CONCLUSIONS

This scoring system involving 5 histologic parameters demonstrates very high discrimination between EED and normal biopsies, indicating that this scoring system can be applied with confidence to studies of intestinal biopsies in EED.

A Case of Multi-Organ Failure Secondary to Malabsorption Occurring in the Presence of Acute-on-Chronic Pancreatitis

This case report highlights a concerning and complex case of a middle-aged female presenting with severe malabsorption, diarrhea, and subsequent malnutrition. The patient's weight dramatically dropped from 85 lbs to 50 lbs over the course of two to four months. The medical history included ongoing pancreatitis, esophageal ulcers, and previous surgeries for a dermoid cyst in the brain and cervical neoplasia. Upon admission to the hospital, the patient received total parenteral nutrition (TPN) on the first day, but this led to delirium due to refeeding syndrome. Refeeding syndrome is a well-known condition that can occur when malnourished individuals receive too much nutrition too quickly, causing metabolic imbalances and potentially serious complications. Subsequently, during the second hospitalization, the patient did not receive TPN but was instead administered 5% dextrose with 20 mEq of potassium chloride (KCl). Unfortunately, her condition worsened, leading to multiorgan failure. During the third hospitalization, TPN was reintroduced under consultation and hospitalist evaluation, and the patient's symptoms improved. Overall, this case report outlines a complex case with multiple medical issues, including severe malnutrition, which required careful management and consideration of the patient's unique needs. It underscores the importance of cautious nutritional support for severely malnourished individuals to avoid complications such as refeeding syndrome. The case also emphasizes the value of interdisciplinary collaboration and continuous monitoring to achieve successful outcomes in such complex situations.

Olmesartan-induced enteropathy associated with antiphospholipid syndrome

Olmesartan-induced enteropathy (OIE) is an emergent enteropathy related to this angiotensin II receptor blocker. Main clinical manifestation is chronic diarrhea and duodenal biopsy is characterized by villous atrophy. Therefore, it is necessary to exclude other causes of enteropathy such as celiac disease, autoimmune enteropathy, intestinal lymphoma, parasitic infections, immunodeficiencies, or Crohn disease. Although it is supposed to be triggered by an immune mechanism, it is not clear its relation to other autoimmune disorders. We report for the first time a case of OIE associated with antiphospholipid syndrome.

The Nutritional Intervention of Resveratrol Can Effectively Alleviate the Intestinal Inflammation Associated With Celiac Disease Induced by Wheat Gluten

Background and Aims

Wheat gluten is a critical trigger for celiac disease, often causing inflammatory lesions and oxidative stress damage in the intestines of patients. In daily life, it is difficult for celiac disease patients to strictly avoid the dietary intake of gluten, which makes complementary preventive therapy particularly urgent. As such, we investigated the alleviating effects of resveratrol in vivo and in vitro models of celiac disease.

Methods

We established in vivo and in vitro models of gluten protein-induced celiac disease. The intervention effect of resveratrol was defined well based on relevant indicators of inflammation, immunity and oxidative stress, and its possible involvement in signaling pathways and genes were also identified.

Results

Resveratrol was effective in reducing intestinal oxidative stress and inflammatory damage induced by wheat gluten in both cell and mouse models for celiac disease. We identified correlations between the genes (Fgf15, Nr0b2, Aire and Ubd) and signaling pathways (PPAR, AMPK and FoxO) in which resveratrol performed critical roles.

Conclusions

Resveratrol contributed to regulate development of autoimmunity through up-regulation of Aire and Ubd genes and promote nutrient absorption in intestine through down-regulation of Fgf15 and Nr0b2 genes, as well as played a role in regulating complex response system of oxidative stress, inflammatory response and immune response in intestine by activating PPAR, AMPK and FoxO signaling pathways, thus effectively alleviating the intestinal symptoms of celiac disease.

Epithelial Abnormalities in the Small Intestine of Zambian Children With Stunting

Background

Environmental enteropathy (EE) contributes to impaired linear growth (stunting), in millions of children worldwide. We have previously reported that confocal laser endomicroscopy (CLE) shows fluorescein leaking from blood to gut lumen in vivo in adults and children with EE. We set out to identify epithelial lesions which might explain this phenomenon in Zambian children with stunting non-responsive to nutritional support.

Methods

We performed confocal laser endomicroscopy (CLE) in 75 children and collected intestinal biopsies for histology in 91 children. CLE videos were evaluated, employing the Watson score to determine severity of leakiness. Morphometry was carried out on well-orientated mucosa and 3 biopsies were examined by electron microscopy.

Results

Confocal laser endomicroscopy demonstrated substantial leakage from circulation to gut lumen in 73 (97%) children. Histology consistently showed characteristic changes of EE: villus blunting, lamina propria and epithelial inflammation, and depletion of secretory cells (Paneth cells and goblet cells). Epithelial abnormalities included marked variability in epithelial height, disorganised and shortened microvilli, dilated intercellular spaces, pseudostratification, formation of synechiae between epithelium on adjacent villi, crypt destruction, and abundant destructive lesions which may correspond to the microerosions identified on CLE.

Conclusion

Epithelial abnormalities were almost universal in Zambian children with non-responsive stunting, including epithelial microerosions, cell-cell adhesion anomalies, and defects in secretory cells which may all contribute to impairment of mucosal barrier function and microbial translocation.

Enteropathies with villous atrophy but negative coeliac serology in adults: current issues

Objective

The differential diagnosis and management of seronegative enteropathies is challenging due to the rarity of these conditions, the overlap of clinical and histopathological features and the current lack of an international consensus on their nomenclature.

Design

This is a narrative review providing pragmatic guide on the investigation and clinical management of seronegative enteropathies in adults based on the available literature and our clinical experience.

Conclusions

Seronegative coeliac disease is the most frequent cause among the heterogeneous group of seronegative enteropathies and its diagnosis is confirmed by the clinical and histological response to a gluten-free diet after the exclusion of other causes of villous atrophy. Correct identification and targeted management of seronegative enteropathies is mandatory because of the variation in terms of clinical outcomes and prognosis.

Adult-Onset Autoimmune Enteropathy in an European Tertiary Referral Center

INTRODUCTION

Adult-onset autoimmune enteropathy (AIE) is a rare cause of severe chronic diarrhea because of small intestinal villous atrophy. We report on patients with adult-onset AIE in an European referral center.

METHODS

Retrospective study including patients diagnosed with AIE in the Amsterdam UMC, location VUmc, between January 2003 and December 2019. Clinical, serological, and histological features and response to treatment were reported. The specificity of antienterocyte antibodies (AEA) was evaluated by examining the prevalence of AEA in (i) controls (n = 30) and in patients with (ii) AIE (n = 13), (iii) celiac disease (CD, n = 52), (iv) refractory celiac disease type 2 (n = 18), and (v) enteropathy-associated T-cell lymphoma (EATL, n = 10).

RESULTS

Thirteen AIE patients were included, 8 women (62%), median age of 52 years (range 23-73), and 6 (46%) with an autoimmune disease. AEA were observed in 11 cases (85%), but were also found in CD (7.7%), refractory celiac disease type 2 (16.7%), and EATL (20%). Ten patients (77%) were human leukocyte antigen DQ2.5 heterozygous. Total parenteral nutrition was required in 8 cases (62%). Steroids induced clinical remission in 8 cases (62%). Step-up therapy with rituximab, cyclosporine, infliximab, and cladribine in steroid-refractory patients was only moderately effective. Four patients died (31%), but 4 (31%) others are in long-term drug-free remission after receiving immunosuppressive treatment, including 1 patient who underwent autologous stem cell transplantation.

DISCUSSION

Adult-onset AIE is a rare but severe enteropathy that occurs in patients susceptible for autoimmune disease. Four patients (31%) died secondary to therapy-refractory malabsorption, while immunosuppressive therapy leads to a long-lasting drug-free remission in one-third of patients.

Small and Large Intestine (I): Malabsorption of Nutrients

Numerous disorders can alter the physiological mechanisms that guarantee proper digestion and absorption of nutrients (macro- and micronutrients), leading to a wide variety of symptoms and nutritional consequences. Malabsorption can be caused by many diseases of the small intestine, as well as by diseases of the pancreas, liver, biliary tract, and stomach. This article provides an overview of pathophysiologic mechanisms that lead to symptoms or complications of maldigestion (defined as the defective intraluminal hydrolysis of nutrients) or malabsorption (defined as defective mucosal absorption), as well as its clinical consequences, including both gastrointestinal symptoms and extraintestinal manifestations and/or laboratory abnormalities. The normal uptake of nutrients, vitamins, and minerals by the gastrointestinal tract (GI) requires several steps, each of which can be compromised in disease. This article will first describe the mechanisms that lead to poor assimilation of nutrients, and secondly discuss the symptoms and nutritional consequences of each specific disorder. The clinician must be aware that many malabsorptive disorders are manifested by subtle disorders, even without gastrointestinal symptoms (for example, anemia, osteoporosis, or infertility in celiac disease), so the index of suspicion must be high to recognize the underlying diseases in time.