Endocrine Abstracts

Objective: Intestinal barrier (IB) is one of the wider human body surface, whose integrity allows the uptake of nutrients also preserving from the entrance of harmful compounds. An increased permeability of IB, known as “leaky gut”, has been demonstrated in patients with intestinal inflammatory and/or autoimmune disorders as well as in patients with autoimmune diseases involving organs far from the intestine, as in patients with Hashimoto’s thyroiditis (HT). The permeability of IB in patients with Hashimoto’s thyroiditis who associate further non-endocrine autoimmune disorders has not been described yet and this is the aim of our study.

Methods: The study group encompassed 93 patients bearing HT (median age=48 years; M=12; F=81); 33 of them associated another non-endocrine autoimmune disorder (HT+POLY) [13 gastric atrophy (HT+GA), 13 non-segmental vitiligo (HT+V) and 7 celiac disease (HT+CD)]. The chronic use of interfering drugs, metabolic, gastrointestinal or chronic disorders, pregnancy, smoking habit, and unbalanced diets have been positively excluded in the enrolled patients. The evaluation of gut permeability was performed by dosing serum zonulin, a regulator of intestinal tight junctions, and LPS, a structural component of the cell membrane of Gram negative bacteria, index of endotoxemia. All subjects underwent venous blood sampling between 8:00 and 9:00 and fasting for at least 12 hours. The serum was stored at -20°until all the samples were simultaneously measured by ELISA kits.

Results: The concentration of zonulin was higher in patients HT+POLY than in patients with isolated HT (P<0.0001); a similar result was observed for LPS concentrations (P=0.0004). The highest concentrations of zonulin as compared to HT may be observed in HT+CD (P<0.0001), followed by HT+GA (P<0.01) and by HT+V (P<0.05). On the contrary, the highest concentration of LPS as compared to HT may be observed in HT+V (P<0.01), followed by HT+GA (P<0.05). In the whole sample and in patients with isolated HT, zonulin and LPS concentrations significantly correlated (P<0.0001;r=0.4431 and r=0.4409, respectively), a correlation lost in patients with HT+POLY. This was due to a greater increase of LPS over zonulin levels (37% vs 31%) in HT+POLY group.

Conclusions: The association of HT with further autoimmune disorders is characterized by a leaky gut, even when the disease does not involve directly the gastrointestinal tract. The higher concentration of LPS in polyautoimmune patients indicates a more severe systemic inflammatory state.