Evaluation and comparison of short chain fatty acids composition in gut diseases.

BACKGROUND: An altered (dysbiosis) and unhealthy status of the gut microbiota is usually responsible for a reduction of short chain fatty acids (SCFAs) concentration. SCFAs obtained from the carbohydrate fermentation processes are crucial in maintaining gut homeostasis and their determination in stool samples could provide a faster, reliable and cheaper method to highlight the presence of an intestinal dysbiosis and a biomarker for various gut diseases. We hypothesize that different intestinal diseases, such as celiac disease (CD), adenomatous polyposis (AP) and colorectal cancer (CRC) could display a particular fecal SCFAs' signature. AIM: To compare the fecal SCFAs' profiles of CD, AP, CRC patients and healthy controls, using the same analytical method. METHODS: In this cross-sectional study, we defined and compared the SCFAs' concentration in fecal samples of 9 AP, 16 CD, 19 CRC patients and 16 healthy controls (HC). The SCFAs' analysis were performed using a gas-chromatography coupled with mass spectrometry method. Data analysis was carried out using Wilcoxon rank-sum test to assess pairwise differences of SCFAs' profiles, partial least squares-discriminate analysis (PLS-DA) to determine the status membership based on distinct SCFAs' profiles, and Dirichlet regression to determine factors influencing concentration levels of SCFAs. RESULTS: We have not observed any difference in the SCFAs' amount and composition between CD and healthy control. On the contrary, the total amount of SCFAs was significantly lower in CRC patients compared to HC (P = 0.044) and CD (P = 0.005). Moreover, the SCFAs' percentage composition was different in CRC and AP compared to HC. In detail, HC displayed higher percentage of acetic acid (P value = 1.3 × 10-6) and a lower amount of butyric (P value = 0.02192), isobutyric (P value = 7.4 × 10-5), isovaleric (P value = 0.00012) and valeric (P value = 0.00014) acids compared to CRC patients. AP showed a lower abundance of acetic acid (P value = 0.00062) and higher percentages of propionic (P value = 0.00433) and isovaleric (P value = 0.00433) acids compared to HC. Moreover, AP showed higher levels of propionic acid (P value = 0.03251) and a lower level of isobutyric acid (P value = 0.00427) in comparison to CRC. The PLS-DA model demonstrated a significant separation of CRC and AP groups from HC, although some degree of overlap was observed between CRC and AP. CONCLUSION: Analysis of fecal SCFAs shows the potential to provide a non-invasive means of diagnosis to detect patients with CRC and AP, while CD patients cannot be discriminated from healthy subjects.

Female Patients with Dermatitis Herpetiformis Show a Reduced Diagnostic Delay and Have Higher Sensitivity Rates at Autoantibody Testing for Celiac Disease.

OBJECTIVE: Our objective was to characterize the demographic information, clinical features, and laboratory data of patients with dermatitis herpetiformis (DH). METHODS: In this multicentre cross-sectional study, consecutive patients with a new diagnosis of DH that referred to nine different Italian centers between 2011 and 2016 were characterized assessing demographic, clinical and laboratory findings, and evaluating gender and age differences across selected variables. RESULTS: A total of 151 patients were included. Among them, 81 (53.6%) were males and 70 (46.4%) were females, with a male to female ratio of 1.2 : 1. The median age at the time of diagnosis was 41 years (range 0-85). Males had a significant longer diagnostic delay if compared to females (9 vs. 3 months, respectively; p = 0.01). Direct immunofluorescence was positive in 94.7% of the patients, while duodenal biopsy showed partial to total villous atrophy in 70.1% of patients. All the females resulted positive to at least one of the antibodies tested, while a total of 12 male patients (10.5%) tested negative to celiac-specific antibodies. Female patients had a high rate (14.1%) of autoimmune thyroiditis. CONCLUSIONS: Our study confirmed some of the most relevant data regarding DH that have been previously reported in the literature. In addition, we found a reduced diagnostic delay in females with respect to males, possibly related to the higher sensitivity of serologic testing in females with DH compared to males. Finally, we demonstrated that intestinal involvement could be severe in patients with DH and that females should be tested for thyroiditis.

Regulatory T cells as well as IL-10 are reduced in the skin of patients with dermatitis herpetiformis.

BACKGROUND: Dermatitis herpetiformis (DH) and celiac disease (CD) are considered as autoimmune diseases that share a defined trigger (gluten) and a common genetic background (HLA-DQ2/DQ8). However, the pathogenesis of DH is not fully understood and no data are available about the immune regulation in such a disease. OBJECTIVE: The aim of this study was to assess if alterations in the pattern of the immune response and, in particular, impairments of regulatory T (Tregs) cells may contribute to the phenotypic differences between DH and CD. METHODS: We investigated the presence of Tregs cell markers, in the skin, the duodenum and the blood of patients with DH by immunohistochemistry, confocal microscopy and flow cytometry. As controls, we included patients with bullous pemphigoid, patients with CD without skin lesions, as well as healthy subjects (HS). RESULTS: In the skin of DH patient, we found a significantly lower proportion of FOXP3(+) Tregs and IL-10(+) cells than in HS (p < 0.001 for both cell populations). In duodenal samples, no differences where found in the proportion of Tregs between patients with DH and patients with CD without skin manifestations. Finally, the frequency of CD25(bright)FOXP3(+) cells within the CD4(+) subset was significantly reduced in CD patients either with or without DH with respect to HS (p = 0.029 and p = 0.017, respectively). CONCLUSIONS: Our findings suggested that a reduction of Tregs may play a major role in the skin, leading to a defective suppressive function and thus to the development of the lesions. By contrast, no differences could be detected about Tregs between patients with DH and patients with CD in the duodenum, suggesting that the mechanisms of the intestinal damage are similar in both diseases.