ESPE Abstracts

Background: due to the well-known association between intestinal permeability and obesity, zonulin has been recently proposed as an indicator of intestinal mucosal barrier integrity. Nevertheless, data about zonulin are extremely scarce in pediatric age.

Objectives: aim of this study was to investigate the relationship between serum and faecal zonulin levels with body mass index (BMI) and biochemical markers of insulin resistance (IR), insulin sensitivity, β-cell function and cardio-metabolic risk in obese non-diabetic children and adolescents.

Methods: children and adolescents aged 5-16 years with BMI ≥ 2.0 SDS were recruited. Criteria of exclusion from the study were pre-term or post-term birth, genetic or endocrine causes of obesity, chronic diseases, or chronic pharmacological therapies. All the patients underwent clinical and biochemical assessment, including oral glucose tolerance test (OGTT), liver ultrasonography (US), and measurement of serum and fecal zonulin levels. Homeostasis model assessment of insulin resistance (HOMA-IR), β-cell function (HOMA-B), Matsuda-index, Insulinogenic-index (IGI), areas under the curves for glucose and insulin were calculated. IR was defined as HOMA-IR >2.5 in prepubertal children and >4 in pubertal youths.

Results: 78 obese patients were enrolled (mean age 11.48 ± 2.54 years). Impaired fasting glucose was documented in 29.5% patients and impaired glucose tolerance in 14.1%. Overall, 69.2% patients had insulin resistance. Liver steatosis was diagnosed in 39.7%. Median serum and faecal zonulin levels were respectively 14.66 ng/ml (range 12.64-19.62) and 76.18 ng/ml (range 46.60-105.44). Serum and faecal zonulin were positively correlated (P = 0.03). Moreover, a positive association between serum and faecal zonulin (OR 0.153;95%CI,0.015-0.291; P = 0.031) was documented by linear regression model. No significant differences in serum and faecal zonulin levels were found for age, sex, pubertal status, glucose, lipid profile and the other obesity-related parameters. An inverse relationship between faecal zonulin and IGI (OR-0.254; 95%CI,-0.106-0.007; P = 0.025) was documented by linear regression analysis and confirmed by the multivariate model (P <0.05), independently from sex, age, BMI, pubertal status, HOMA-B and steatosis. A negative association between faecal zonulin and HOMA-B was also recorded, although this finding did not reach statistical significance (P = 0.07).

Conclusion: the present study described for the first time serum and faecal zonulin levels in a pediatric cohort with obesity. Our results highlighted a close, negative, association between faecal zonulin and IGI. Insulin sensitivity seems to significantly influence faecal zonulin concentrations in children and adolescents with obesity. Even if further studies are needed, these data may support the role of faecal zonulin as a reliable non-invasive biomarker of IR.