Circulating microRNAs as novel non-invasive biomarkers of paediatric celiac disease and adherence to gluten-free diet

Background

Celiac Disease (CD) is a multifactorial autoimmune enteropathy (with a prevalence of approximately 1% worldwide) that exhibits a wide spectrum of clinical, serological and histological manifestations. For the diagnosis of paediatric CD, the gold standard is the combination of serological tests (with high TGA-IgA values greater than 10 times the upper limit of normal) and duodenal biopsy (with a positive TGA-IgA but low titer). Therefore, a diagnostic test that totally excludes an invasive approach has not been discovered so far and the discovery of novel biological markers would represent an undoubted advantage for the diagnosis of CD and prognostic evaluation. MicroRNAs (miRNAs), small non-coding RNAs (18–22 nucleotides) that regulate gene expression at post-transcriptional level and play important roles in many biological processes, represent a novel class of potential disease biomarkers. Their presence in biological fluids (i.e., serum, plasma, saliva, urine) provides the opportunity to employ circulating miRNAs as novel non-invasive biomarkers.

Methods

In our prospective observational study, we examined the expression of circulating miRNAs in a cohort of CD patients (both at diagnosis and on gluten-free diet, respectively referred as CD and GFD) compared to healthy controls. By small RNA-Seq we discovered a set of circulating miRNAs that were further validated by qPCR with specific assays.

Findings

We found that out of the 13 miRNAs able to discriminate the three groups (i.e., CD, GFD and controls), three of them, namely miR-192-5p, miR-215-5p and miR-125b-5p (alone or in combination), were able to discriminate these three groups with high accuracy and specificity.

Interpretation

Our conclusions emphasize that these circulating miRNAs can be employed not only for the diagnosis of CD patients with a low TGA-IgA titer but also to monitor the adherence to a gluten-free diet by CD patients. In conclusion, we suggest the use of the circulating miRNAs identified in this work as a novel diagnostic and follow-up tool for paediatric CD.

Funding

This work was supported by Fondazione Celiachia Onlus (FC) Grant n° 018/FC/2013 and by Italian Ministry of Health (Ricerca Corrente).

The overweight: a rare presentation of celiac disease

We describe the nutritional status of a cohort of celiac disease (CD) children at presentation and during follow-up on gluten-free diet (GFD). Two Italian centers (Rome and Bari) prospectively enrolled 445 biopsy-confirmed CD children, diagnosed between 2009 and 2013. Body Mass Index was used as a measure of nutritional status according to Italian growth charts of Cacciari. The overweight/obese subject was 7.8% at onset and did not significantly increase during follow-up (9.8% at final assessment). The prevalence of overweight/obesity was significantly higher among males than females. Furthermore, overweight/obesity children as compared with those with normal weight were significantly older and had significantly lower levels of tTG antibodies. This study shows that some CD children are obese/overweight at diagnosis; therefore, overweight/obesity can be considered a rare but a possible mode of CD presentation. Thus, CD diagnosis must be considered even in overweight/obese children where this diagnosis can be easily missed.

Insulin resistance and exercise capacity in male children and adolescents with non-alcholic fatty liver disease

Insulin resistance (IR) and obesity may be associated with impaired response to physical exercise. We aimed at assessing physical capacity in obese children with biopsy proven non-alcoholic fatty liver disease (NAFLD) as compared to normal weight and obese children without fatty liver disease. All male subjects, 20 NAFLD and 31 control individuals (20 obese, without NAFLD and 11 normal weight children) took part in the study. We evaluated changes in cardiovascular parameters during a bicycle-ergometer exercise test (James' test). Duration, power of exercise, heart rate (HR), blood pressure (BP), pulse pressure, cardiac output ((I)CO) and total peripheral vascular resistance indexed for height ((I)TPVR) were recorded at rest ((r)) and peak ((p)) exercise. The homeostatic model assessment was used to determine insulin resistance (HOMA-IR) and beta-cell action (HOMA-beta cell). In NAFLD and obese subjects, fasting leptin, insulin secretion, insulinogenic index (IGI), muscle insulin sensitivity (MISI) and hepatic insulin resistance index (HIRI) were assayed. Children with NAFLD were the most insulin-resistant (P = 0.001), and showed higher HIRI than obese controls (P = 0.05). At rest, they had the lowest values of SBP(r) (P = 0.001 vs. controls and P < or = 0.05 vs. obese controls); during the test, the highest values of (I)CO(p) (P = 0.005), Delta(I)CO (P = 0.003) and DeltaTRVP(p) (P < or = 0.0001). NAFLD and obese controls both had impaired DeltaHR(p) (P < or = 0.0001). However, obese controls were not able to reduce peripheral resistance during the test. HOMA-IR explained 28% of variance in Delta(I)CO of the whole sample, (P < or = 0.0001). In obese children with or without NAFLD, increased IR and body weight may induce cardiovascular compensatory changes in response to physical exercise with fairly different pathogenetic mechanisms, which are likely to be dependent on the different degree of IR.