Concise Review: Cellular Therapies: The Potential to Regenerate and Restore Tolerance in Immune-Mediated Intestinal Diseases

Chronic inflammatory enteropathies, including celiac disease, Crohn's disease, and ulcerative colitis, are lifelong disabling conditions whose cure is still an unmet need, despite the great strides made in understanding their complex pathogenesis. The advent of cellular therapies, mainly based on the use of stem cells, represents a great step forward thanks to their multitarget strategy. Both hematopoietic stem cells (HSC) and mesenchymal stem/stromal cells (MSC) have been employed in the treatment of refractory cases with promising results. The lack of immunogenicity makes MSC more suitable for therapeutic purposes as their infusion may be performed across histocompatibility locus antigen barriers without risk of rejection. The best outcome has been obtained when treating fistulizing Crohn's disease with local injections of MSC. In addition, both HSC and MSC proved successful in promoting regeneration of intestinal mucosa, and favoring the expansion of a T-cell regulatory subset. By virtue of the ability to favor mucosal homeostasis, this last cell population has been exploited in clinical trials, with inconsistent results. Finally, the recent identification of the epithelial stem cell marker has opened up the possibility of tissue engineering, with an array of potential applications for intestinal diseases. However, the underlying mechanisms of action of these interconnected therapeutic strategies are still poorly understood. It is conceivable that over the next few years their role will become clearer as the biological interactions with injured tissues and the hierarchy by which they deliver their action are unraveled through a continuous moving from bench to bedside and vice versa. Stem Cells 2016;34:1474-1486.

Reducing the risk of hospital admission: a call to action from the Italian Society of Internal Medicine

The belief that hospital stays may constitute per se a risk for patients is not widespread among patients and health care professionals. In the balance between advantages and disadvantages of admission, we rarely take into account the impact of the hospital stay itself on the well-being of the patient. In a society that is getting older the hospital may become a hostile environment for the complex and frail patient. Reducing the risks associated with hospital admission implies a radical cultural change accepted and shared by all health care professionals. The critical reconsideration of admission is a way of reasoning not only on hospitalisation but also on what the correct health outcome paradigms should be.

The effect of gluten on intestinal fermentation, gastric and gallbladder emptying in healthy volunteers

BACKGROUND

The relationship between gluten ingestion and gastrointestinal tract function is a matter of debate.

AIM

We analysed the effect of gluten on gastric and gallbladder emptying and intestinal fermentation in healthy volunteers.

METHODS

Ultrasound measurement of gastric and gallbladder emptying after both gluten-containing and gluten-free meals was performed in 18 volunteers (8 women, age 25.0±2.5 years; BMI 22±1.9). Breath hydrogen excretion after a gluten-containing meal, a gluten-free meal and a gluten-free meal with added gluten powder was measured in 16 volunteers (10 women, age 25.2±2.7 years; BMI 22±1.8). The severity of symptoms was monitored.

RESULTS

Gluten presence in the meals was not recognised. Gastric emptying time was 81.6±13.8min after gluten-containing and 73.9±21.6min after gluten-free meals (p=0.11). Percentage ejection fraction after gluten-containing meals was 60±9% and 60.6±6% after gluten-free meals (p=0.68). Peak and cumulative hydrogen excretion were significantly higher after gluten-containing than after gluten-free meals (peak: 12.5±7.3 vs 6.5±5.1 parts-per-million, p<0.01; and cumulative: 2319±1720 vs 989±680 parts-per-million/minute, respectively; p<0.01). Adding gluten powder to the gluten-free meal did not modify fermentation. Symptoms were mild and not different after the meals.

CONCLUSIONS

In healthy volunteers, gluten may induce gastrointestinal alterations. Further studies are needed to clarify which patients could benefit from dietary modification.

Long-Term Follow-Up of Crohn Disease Fistulas After Local Injections of Bone Marrow-Derived Mesenchymal Stem Cells

OBJECTIVE

To assess the long-term outcome of patients treated with serial intrafistular injections of autologous bone marrow-derived mesenchymal stem cells (MSCs) for refractory Crohn fistulas in terms of safety and efficacy.

PATIENTS AND METHODS

Starting from January 10, 2007, through June 30, 2014, clinical evaluation, calculation of the Crohn disease activity index (CDAI), therapeutic management, and documentation of adverse events in 8 of the 10 patients (5 men; median age, 37 years) who had been injected locally with MSCs were prospectively recorded for 72 months. Cumulative probabilities of fistula recurrence and medical or surgical treatment were estimated using a Kaplan-Meier method, whereas differences among the pre- and post-MSC CDAI values were calculated with the Mann-Whitney U test.

RESULTS

Following disease remission observed after 12 months from MSC treatment (P<.001), the mean CDAI score increased significantly during the subsequent 2 years (P=.007), and was then followed by a gradual decrease, with the patients achieving remission again (P=.02) at the end of the 5-year follow-up. The probability of fistula relapse-free survival was 88% at 1 year, 50% at 2 years, and 37% during the following 4 years, and the cumulative probabilities of surgery- and medical-free survival were 100% and 88% at 1 year, 75% and 25% at 2, 3, and 4 years, and 63% and 25% at 5 and 6 years, respectively. No adverse events were recorded.

CONCLUSION

Locally injected MSCs constitute a safe therapy that rescues refractory patients and regains responsiveness to drugs previously proved ineffective.

Breath Methane Excretion Is not An Accurate Marker of Colonic Methane Production in Irritable Bowel Syndrome

OBJECTIVES

The role of colonic methane production in functional bowel disorders is still uncertain. In small samples of irritable bowel syndrome (IBS) patients, it was shown that methane breath excretion correlates with clinical presentation and delayed gastrointestinal transit time. The aim of this study was to evaluate the relationship between intestinal production and breath excretion of CH4 and to correlate CH4 production with the presence and the severity of symptoms, in a large cohort of IBS patients and in a group of healthy volunteers.

METHODS

A group of 103 IBS patients and a group of 28 healthy volunteers were enrolled. The presence and severity of symptoms and gastrointestinal transit were evaluated in all subjects, who underwent breath H2/CH4 measurement for 7 h after lactulose to identify breath excretors of these gases; H2 and CH4 were also measured in rectal samples to identify colonic producers. Cumulative H2 and CH4 excretion and production were evaluated by the area under the time-concentration curve calculation (AUC).

RESULTS

In IBS patients, CH4 was detected in rectal samples in 48 patients (47%), but only 27 of them (26% of the 103 enrolled patients) excreted this gas with breath. In CH4 producers, the prevalence and severity of symptoms and gastrointestinal transit time were not significantly different with respect to non-producers. IBS subtypes were homogeneously represented in CH4 producers and in non-producers. Healthy volunteers, compared with IBS patients, showed a significantly lower prevalence of CH4 excretion, whereas no difference was found in the prevalence of colonic CH4 production; moreover, in healthy volunteers compared with IBS, CH4 breath excretion and CH4 production were not different in quantitative terms.

CONCLUSION

Our data show that colonic CH4 production is not associated with clinical presentation in IBS patients and does not correlate with symptom severity or with gastrointestinal transit time. Clinical inferences based on breath CH4 excretion should undergo an in-depth revision, as this method is not a good marker of CH4 colonic production.

Human cytomegalovirus and Epstein-Barr virus infection in inflammatory bowel disease: Need for mucosal viral load measurement

AIM: To evaluate the best diagnostic technique and risk factors of the human Cytomegalovirus (HCMV) and Epstein-Barr virus (EBV) infection in inflammatory bowel disease (IBD).

METHODS: A cohort of 40 IBD patients (17 refractory) and 40 controls underwent peripheral blood and endoscopic colonic mucosal sample harvest. Viral infection was assessed by quantitative real-time polymerase chain reaction and immunohistochemistry, and correlations with clinical and endoscopic indexes of activity, and risk factors were investigated.

RESULTS: All refractory patients carried detectable levels of HCMV and/or EBV mucosal load as compared to 13/23 (56.5%) non-refractory and 13/40 (32.5%) controls. The median DNA value was significantly higher in refractory (HCMV 286 and EBV 5.440 copies/10⁵ cells) than in non-refractory (HCMV 0 and EBV 6 copies/10⁵ cells; P < 0.05 and < 0.001) IBD patients and controls (HCMV and EBV 0 copies/10⁵ cells; P < 0.001 for both). Refractory patients showed DNA peak values ≥ 10³ copies/10⁵ cells in diseased mucosa in comparison to non-diseased mucosa (P < 0.0121 for HCMV and < 0.0004 for EBV), while non-refractory patients and controls invariably displayed levels below this threshold, thus allowing us to differentiate viral colitis from mucosal infection. Moreover, the mucosal load positively correlated with the values found in the peripheral blood, whilst no correlation with the number of positive cells at immunohistochemistry was found. Steroid use was identified as a significant risk factor for both HCMV (P = 0.018) and EBV (P = 0.002) colitis. Finally, a course of specific antiviral therapy with ganciclovir was successful in all refractory patients with HCMV colitis, whilst refractory patients with EBV colitis did not show any improvement despite steroid tapering and discontinuation of the other medications.

CONCLUSION: Viral colitis appeared to contribute to mucosal lesions in refractory IBD, and its correct diagnosis and management require quantitative real-time polymerase chain reaction assay of mucosal specimens.

Relationship between carotid intima-media thickness and non valvular atrial fibrillation type

OBJECTIVE

Carotid intima-media thickness (cIMT) is a surrogate marker of subclinical atherosclerosis and it is able to predict both coronary and cerebral vascular events. No data exist on the association between cIMT and non valvular atrial fibrillation (NVAF) type. We conduct this study with the aim to analyze the association between abnormal cIMT and NVAF type.

METHODS

A cross-sectional study of the "Atrial fibrillation Registry for Ankle-brachial index Prevalence Assessment-Collaborative Italian Study (ARAPACIS)" has been performed. Among 2027 patients enrolled in the ARAPACIS, 673 patients, who underwent carotid ultrasound examination to assess cIMT, were included in the study.

RESULTS

Among the entire population, 478 patients (71%) had cIMT > 0.90 mm. Patients with an abnormal cIMT (>0.90 mm) were significantly older and more likely hypertensive, diabetic and with a previous history of stroke than those with normal cIMT (≤0.90 mm). These patients had more permanent/persistent NVAF and CHA2DS2-VASc score ≥ 2 (p < 0.0001) compared to those with cIMT <0.90 mm. Excluding all patients affected by previous cardiovascular disease, logistic regression analysis showed that independent predictors of abnormal cIMT were: age class 65-74 yrs. (p < 0.001), age class ≥75 yrs. (p < 0.001), arterial hypertension (p < 0.001), calcium-channel blockers use (p < 0.001) and persistent/permanent NVAF (p = 0.001).

CONCLUSION

Our findings show a high prevalence of abnormal cIMT in NVAF patients, reinforcing the concept that NVAF and systemic atherosclerosis are closely associated. Abnormal cIMT was particularly evident in persistent/permanent NVAF suggesting a more elevated atherosclerotic burden in patients with long-standing NVAF.

TRIAL REGISTRATION

http://clinicaltrials.gov/ct2/show/NCT01161251.

Medication prescription and adherence disparities in non valvular atrial fibrillation patients: an Italian portrait from the ARAPACIS study

Non-valvular atrial fibrillation (NVAF) represents a major health-care problem, needing an extensive and strict thrombosis prevention for stroke and cardiovascular (CV) disease risks. NVAF management guidelines recommend adequate antithrombotic and anti-atherosclerotic therapies. Medication adherence has been recognized as a pivotal element in health quality promotion and in the achievement of better clinical outcomes. We conducted a post-hoc analysis of the "Atrial fibrillation Registry for Ankle-brachial index Prevalence Assessment-Collaborative Italian Study (ARAPACIS)" with the aim of discerning differences in pharmacological management and medication adherence among NVAF Italian patients. Furthermore, data were analysed according to Italian geographical macro-regions (North, Center, South) to evaluate whether socioeconomic conditions might also influence medication adherence. Thus, we selected 1,366 NVAF patients that fulfilled the Morisky Medication Adherence Scale-4 items. Regional disparities in drug prescriptions were observed. In particular, in high-risk patients (CHA2DS2-VASc ≥2) oral anticoagulants were more prescribed in Northern and Center patients (61 and 60 %, respectively) compared to 53 % of high-risk Southern patients. Also, medication adherence showed a progressive decrease from North to South (78 vs. 60 %, p < 0.001). This disparity was independent of the number of drugs consumed for any reason, since prevalence of poly-therapy among the three macro-regions was similar. Our results show regional differences in NVAF patients' antithrombotic management and medication adherence, potentially reflecting well-known disparities in socioeconomic status among Italian regions. Future interventions promoting campaigns to global health-care education may be desirable to improve clinical outcomes in NVAF patients.

Hydrogen breath test in patients with severe constipation: the interference of the mixing of intestinal content

BACKGROUND

The diagnostic accuracy of the hydrogen (H2 ) breath test might be reduced by the release of preformed H2 , trapped in hard stools. Test solution ingestion might induce the mixing of colonic content and a false positive result. We studied severely constipated patients, at diagnosis and after the normalization of bowel function, to clarify whether this mechanism affects test results.

METHODS

Twenty functional constipated patients, 10 consecutive patients with functional diarrhea and 10 healthy volunteers underwent (i) a H2 breath test after lactulose, to exclude differences among the groups in fermenting capacity; (ii) breath H2 excretion monitoring after non-absorbable, non-fermentable PEG-electrolyte solution, to exclude the role of the delivery to the colon of preexisting fermentable substrates or of the release of preformed H2 entrapped in the feces; (iii) H2 measurement during a 7-h fasting period, to exclude the role of spontaneous variations of breath gas excretion; and (iv) breath H2 excretion monitoring after PEG, after normalization of bowel function.

KEY RESULTS

All the subjects excreted similar amounts of H2 after lactulose. After PEG, only severely constipated patients showed significant breath H2 excretion, theoretically able to induce a false positivity of the lactose breath test in 70% of patients and a false positivity of glucose breath tests in 50% of patients. Breath H2 excretion after PEG disappeared if fecal consistency improved after therapy.

CONCLUSIONS & INFERENCES

Severely constipated patients may harbor preformed gas in hard stools which can be released when mixing of the intestinal content is induced. This mechanism may interfere with breath test results.

Fasting and postprandial gastric sensorimotor activity in functional dyspepsia: postprandial distress vs. epigastric pain syndrome

OBJECTIVES

Little information is available on the mechanisms responsible for dyspeptic symptoms in postprandial distress syndrome (PDS), characterized by the presence of prevalently meal-related early satiation and fullness, and the epigastric pain syndrome (EPS), characterized by the prominent symptom of epigastric pain, generally not meal related. In a group of PDS patients, the presence of hypersensitivity to gastric distension in both fasting and postprandial phases was described as the main pathophysiological mechanism; on the contrary, we have no information on the pathophysiology of EPS.

METHODS

Sixty Helicobacter pylori (HP)-negative, irritable bowel syndrome (IBS)-negative, and gastroesophageal reflux disease (GERD)-negative patients with functional dyspepsia according to Rome III criteria underwent symptom, anxiety, depression, and somatization evaluation, gastric barostat test, and gastric emptying time evaluation for solids. Fifteen age- and sex-matched healthy volunteers (HVs) were also enrolled as a control group.

RESULTS

In PDS patients, the prevalence of both fasting and postprandial hypersensitivity was higher than in EPS patients, and the extent of postprandial reduction of discomfort threshold was significantly correlated with symptom severity. In EPS patients, gastric volume at fasting discomfort threshold and fasting compliance were significantly lower than in PDS patients. Gastric emptying time and gastric accommodation were similar between the two dyspeptic groups. Dyspeptic patients showed a higher prevalence of psychiatric disorders than HVs, but the prevalence was similar between PDS and EPS patients.

CONCLUSIONS

Fasting and postprandial hypersensitivity characterize PDS patients and a reduction of gastric compliance is present in EPS patients. However, the pathophysiology of EPS appears more complex than PDS and further studies are needed to analyze central processing and integration of afferent pathways in order to clarify the role of the central nervous system in this condition.

Bedside ultrasonography (US), Echoscopy and US point of care as a new kind of stethoscope for Internal Medicine Departments: the training program of the Italian Internal Medicine Society (SIMI)

In recent years, thanks to the development of miniaturized ultrasound devices, comparable to personal computers, tablets and even to smart phones, we have seen an increasing use of bedside ultrasound in internal medicine departments as a novel kind of ultrasound stethoscope. The clinical ultrasound-assisted approach has proved to be particularly useful in assessing patients with nodules of the neck, dyspnoea, abdominal pain, and with limb edema. In several cases, it has allowed a simple, rapid and precise diagnosis. Since 2005, the Italian Society of Internal Medicine and its Ultrasound Study Group has been holding a Summer School and training courses in ultrasound for residents in internal medicine. A national network of schools in bedside ultrasound was then organized for internal medicine specialists who want to learn this technique. Because bedside ultrasound is a user-dependent diagnostic method, it is important to define the limits and advantages of different new ultrasound devices, to classify them (i.e. Echoscopy and Point of Care Ultrasound), to establish appropriate different levels of competence and to ensure their specific training. In this review, we describe the point of view of the Italian Internal Medicine Society on these topics.

Serum regenerating islet-derived 3-alpha is a biomarker of mucosal enteropathies

BACKGROUND

The clinical presentation of organic and functional intestinal disorders can overlap and clinicians often rely on invasive and time-consuming procedures to make a final diagnosis. Regenerating islet-derived 3-alpha (Reg3α) is detectable in the circulation of patients with intestinal graft-versus host disease and patients with inflammatory bowel disease (IBD).

AIM

To determine whether serum Reg3α testing is useful for discriminating mucosal enteropathies from functional intestinal disorders.

METHODS

We prospectively included 47 patients with active coeliac disease (ACD), 13 patients with refractory coeliac disease (RCD), seven patients with common variable immunodeficiency (CVID), 72 patients with active Crohn's disease, 22 patients with active ulcerative colitis (UC) and 28 patients with irritable bowel syndrome (IBS)-related diarrhoea. Sera were also taken from 10 CD patients before and after 6-12 months of a gluten-free diet (GFD) and from 14 patients with IBD before and after induction therapy with Infliximab (IFX). Sera of 119 healthy volunteers were used to determine the cut-off value. Reg3α levels were measured by a commercial ELISA kit.

RESULTS

Levels of Reg3α exceeded the cut-off value of the assay in 43/47(91%) ACD patients, 13/13(100%) RCD patients, 7/7(100%) CVID patients, 65/72(90%) Crohn's disease patients, 17/22(77%) UC patients and one patient with IBS(4%). Reg3α levels distinguished mucosal enteropathies from IBS with a sensitivity of 90% and a specificity of 96%. Reg3α levels significantly decreased in CD patients following a GFD and in IBD patients after treatment with IFX.

CONCLUSION

Reg3α is a serum biomarker of intestinal damage that, combined with clinical data, identifies patients who should undergo invasive tests for diagnosing enteropathies.

A second duodenal biopsy is necessary in the follow-up of adult coeliac patients

INTRODUCTION

Coeliac disease is a chronic enteropathy requiring a close follow-up. However, the best way to follow up coeliac patients has not yet been established. In the last 14 years, we have been offering patients a thorough series of periodical examinations including a histological re-evaluation at 12-18 months.

PATIENTS AND METHODS

The notes of all coeliac patients attending our clinic between September 1999 and March 2013 were examined.

RESULTS

Data from 317 adult patients were collected. Duodenal biopsy showed a lack of satisfactory histological response in 25/317 patients; endomysial antibodies were still positive in 76, and diet adherence and clinical response were unsatisfactory in 58 and 97, respectively. Correlations of serological data, clinical response, and diet adherence with histological findings were evaluated. Although the P values showed statistically significant differences, sensitivity and specificity were disappointing: 64% and 80% for serological response, 48% and 71% for clinical response, 56% and 85% for diet adherence.

CONCLUSIONS

After 12-18 months on a gluten-free diet, 8% of the patients do not present a satisfactory histological response; only some of them could have been identified with a serological and/or clinical re-evaluation. Therefore, a duodenal biopsy seems to be the only tool that could identify patients with unsatisfactory histological response.

A multicentre case control study on complicated coeliac disease: two different patterns of natural history, two different prognoses

Background

Coeliac disease is a common enteropathy characterized by an increased mortality mainly due to its complications. The natural history of complicated coeliac disease is characterised by two different types of course: patients with a new diagnosis of coeliac disease that do not improve despite a strict gluten-free diet (type A cases) and previously diagnosed coeliac patients that initially improved on a gluten-free diet but then relapsed despite a strict diet (type B cases). Our aim was to study the prognosis and survival of A and B cases.

Methods

Clinical and laboratory data from coeliac patients who later developed complications (A and B cases) and sex- and age-matched coeliac patients who normally responded to a gluten-free diet (controls) were collected among 11 Italian centres.

Results

87 cases and 136 controls were enrolled. Complications tended to occur rapidly after the diagnosis of coeliac disease and cumulative survival dropped in the first months after diagnosis of complicated coeliac disease. Thirty-seven cases died (30/59 in group A, 7/28 in group B). Type B cases presented an increased survival rate compared to A cases.

Conclusions

Complicated coeliac disease is an extremely serious condition with a high mortality and a short survival. Survival depends on the type of natural history.

Autologous human cytomegalovirus-specific cytotoxic T cells as rescue therapy for ulcerative enteritis in primary immunodeficiency

PURPOSE

Patients affected by primary immunodeficiency usually undergo a wide range of infections, including reactivation of latent ones. Here we report two cases suffering from late-onset combined immunodeficiency in which ulcerative enteritis due to human Cytomegalovirus caused a life-threatening malabsorption syndrome.

METHODS

The assessment of the viral load was carried out on both blood and mucosal samples by quantitative real-time polymerase chain reaction assay. The generation of autologous virus-specific cytotoxic T cell lines was performed according to Good Manufacturing Practice protocol after peripheral blood mononuclear cells were collected through a single leukapheresis.

RESULTS

In both patients, the viral load resulted negligible in peripheral blood, but very high in mucosal specimens (range 1.064 - 1.031.692 copies/10(5) cells). After two rounds of antiviral therapy proved unsuccessful, the generation of virus-specific cytotoxic T cell lines was carried out despite severe lymphopenia, and their infusion resulted safe and durably effective in healing intestinal ulcerations and resetting the viral load.

CONCLUSIONS

Virus-specific cellular therapy was useful in reconstituting specific immunity and treating severe human Cytomegalovirus-related enteritis in patients with primary immunodeficiency.

Coeliac disease: an old or a new disease? History of a pathology

The celiac disease is an ancient pathology, present since the introduction of the wheat in the diet, of which the first description of the compatible clinical symptoms and signs goes back to 250 A.D. Today it is known that the expression of this pathology is multifaceted, ranging from clinical features indicative of bowel disease and malabsorption, until symptoms once unexpected, because of their extra-digestive clinical features. With our work, we wanted to retrace the history of this disease, correlating it with the intake of gluten present in wheat after cooking , ever since mankind has increased the cultivation of cereals. Re-evaluating the clinical and instrumental methods for the diagnosis of Celiac Disease, and benefitting from the most modern techniques for the morphological, biochemical and genetic study of the patients, we sought to understand whether the incidence of the disease is actually increased or if has been considered less frequent for the lower valuation of the signs once deemed more atypical, but currently considered preliminary indicative of the pathology, for its association with other autoimmune diseases, and for the study of some genetic and familiar characteristics. Each of these factors has led the modern medicine to increase epidemiological studies and expand the research potential carriers of celiac disease with safer diagnostic tests.

Relationship between previous treatments and onset of symptoms in patients with Whipple's disease

The clinical features of Whipple's disease (WD) consist of arthropathy that precedes the involvement of other organs, such as the gastrointestinal tract, nervous system and heart. It has been shown that gastrointestinal manifestations can be precipitated by immunosuppressive therapy used to control the arthropathy. In the present study, we investigated the clinical features of the Italian population of patients affected by WD. The clinical histories of 22 patients with WD were reviewed. Relationship between previous treatments and onset of symptoms was analysed. 20/22 patients suffered from arthropathy that had started before gastrointestinal complaints; gastrointestinal symptoms were present in 18 patients and neurological involvement was found in 5. WD must always be taken into account in male patients with long-standing ill-defined arthropathy, and it should be ruled out before starting immunosuppressive or antibiotic treatment that can make correct diagnosis and management very difficult.

Increase in neuroendocrine cells in the duodenal mucosa of patients with refractory celiac disease

OBJECTIVES

Several immune-mediated gastrointestinal disorders, including celiac disease (CD), are associated with neuroendocrine cell hyperplasia. However, neuroendocrine cells have never been explored in refractory CD (RCD).

METHODS

Serial duodenal sections from 17 patients with RCD (6 type 1 and 11 type 2), 16 uncomplicated CD patients before and after gluten-free diet, 14 patients with potential CD, 27 patients with non-CD villous atrophy, i.e., common variable immunodeficiency (n=12), Whipple's disease (n=10) and giardiasis (n=5), and 16 healthy subjects were processed for the immunohistochemical detection of chromogranin A (CgA), serotonin, and somatostatin. Mucosal tryptophan hydroxylase (TpH)-1 and serotonin-selective reuptake transporter (SERT) transcripts were measured by quantitative reverse transcription-PCR. Serum CgA and 24-h urine 5-hydroxyindoleacetic acid (5-HIAA) were assessed. Biopsies from treated CD patients were cultured with serotonin or peptic tryptic digest of gliadin (PT-gliadin), and interferon (IFN)-γ was detected by ELISA in culture supernatants.

RESULTS

Epithelial cells positive for CgA and serotonin, but not somatostatin, were significantly increased in RCD. Raised mucosal transcripts of TpH-1, but not SERT, were found in RCD. On biopsies from treated CD patients, serotonin upregulated IFN-γ production at levels comparable to those induced by PT-gliadin. Serum CgA, but not urine 5-HIAA, was increased in RCD. No significant difference was found between RCD type 1 and type 2 in terms of neuroendocrine cells, mucosal TpH-1 transcripts, and serum CgA.

CONCLUSIONS

Serotonin-producing neuroendocrine cells are increased in RCD mucosa. IFN-γ upregulation induced by serotonin suggests that this monoamine may have a role in sustaining the local inflammatory response in CD.

Diagnosing small bowel malabsorption: a review

Malabsorption encompasses dysfunctions occurring during the digestion and absorption of nutrients. A small proportion of patients presents with chronic diarrhoea. A clinical history supportive of malabsorption may guide investigations toward either the small bowel or pancreas. Serological testing for coeliac disease will determine most cases without invasive investigations. In the clinical context of persisting weight loss and malnutrition, small bowel enteropathy may be investigated with small intestinal biopsies. Small bowel absorptive capacity and permeability might be measured by oral sugar-mix ingestion. Further, approaches to the investigation of malabsorption might also involve the detection in faeces of a substance that has not been absorbed. A variation of the latter is the use of breath testing which relies on the breakdown of the malabsorbed test substance by colonic flora. Measurement of protein absorption is difficult and unreliable; it is, therefore, rarely advocated in clinical settings. No single biological marker confirming a diagnosis of small bowel malabsorption or small bowel integrity is presently available in clinical practice. Plasma citrulline concentration, an amino acid not incorporated into endogenous or exogenous proteins, has been extensively used in research studies and supportive results are establishing its concentration as a reliable quantitative biomarker of enterocyte absorptive capacity.