The relationship between zonulin levels and indicators of lipid metabolism in patients with metabolic associated fatty liver disease in combination with type 2 diabetes mellitus
Authors: Didyk O. K. , Chernyavskyi V. V. 
Published: November 2023

Objective — to determine the relationship between zonulin level and indicators of lipid metabolism in patients with metabolic associated fatty liver disease (MAFLD) in combination with type 2 diabetes mellitus (DM).
Materials and methods. The study involved 64 patients with MAFLD in combination with type 2 diabetes, who were examined and divided into 2 groups. The first group included 35 patients with MAFLD in combination with type 2 diabetes without bacterial overgrowth syndrome (SIBO). The second group included 29 patients with MAFLD in combination with type 2 DM and SIBO. The control group consisted of 18 practically healthy individuals. To assess lipid metabolism disorders, the following indicators were studied: total cholesterol (THC), triglycerides (TG), very low density lipoprotein (VLDL) cholesterol, low‑density lipoprotein (LDL) cholesterol, high‑density lipoprotein (HDL) cholesterol, atherogenic index (AI), non‑HDL cholesterol. The content of serum zonulin was determined by ELISA using test systems IDK Zonulin ELISA, KR5601 (Immunodiagnostic AG, Germany).
Results. Significant increase of serum zonulin levels was established in patients with MAFLD in combination with type 2 diabetes without SIBO 65.57±3.14 ng/mL and with MAFLD in combination with type 2 diabetes and SIBO 84. 21±2.42 ng/mL compared with the control group 13.62±2.35 ng/mL (p <0.001), respectively. When comparing zonulin levels in patients of the first and second groups, a significant increase was observed in patients of the second group compared with patients of the first group (p <0.001), respectively. When comparing lipid metabolism indicators in the studied groups, a significant increase in the content of THC was found 5.69 (5.41—5.86) mmol/L and 5.73 (5.17—5.98) mmol/L, TG 1.97 (1.88—2.16) mmol/L and 2.0 (1.9—2.11) mmol/L, LDL cholesterol 3.73±0.06 mmol/L and 3.85±0.12 mmol/L, VLDL cholesterol 1.13 (0.91—1.28) mmol/L and 1.18 (0.89—1.32) mmol/L, non‑HDL cholesterol 4.68±0.07 mmol/L and 4.63±0.09 mmol/L, AI 4.32 (4.15—4.79) and 4.47 (4.14—4.76) and a decrease in HDL cholesterol 0.94±0.02 and 0.96±0.05 in patients with MAFLD in combination with type 2 diabetes without SІBO and SIBO compared with the control group (p <0.001). The levels of indicators in patients of the first and second groups did not differ significantly (p >0.05). As a result of correlation studies between the zonulin serum levels and lipid profile indicators in patients of the first and second groups, a direct moderate correlation was established between the levels of zonulin and triglycerides, a weak correlation with total cholesterol and cholesterol of very low density, non‑HDL cholesterol, atherogenic index and inverse moderate correlation with high‑density lipoprotein cholesterol.
Conclusions. As a result of the study, the increase of intestinal permeability was revealed in patients with MAFLD in combination with type 2 DM, with or without SIBO. The increased serum levels of zonulin correlated with the indicators of lipid metabolism.