Introduction
The part of NAFLD children has a progressive sub-phenotype known as nonalcoholic steatohepatitis (NASH), characterized by the ability to develop advanced fibrosis, cirrhosis, and end-stage liver disease [1]. Given the high prevalence of NAFLD and invasiveness of the liver biopsy, there is an essential need to find safe non-invasive modalities to determine liver fibrosis in children [2].
Aims & Methods
To investigate serum fibrosis markers in obese children with non-alcoholic fatty liver disease (NAFLD) depending on the presence of liver fibrosis.
94 children aged 9 to 17 years (average age 12.15 ± 2.51 years) were included in the study. According to the transient elastography data (FibroScan®502touch, Echosence, France) and body mass index, children were divided into four groups: group 1 - 27 obese NAFLD children with fibrosis ≥F1, group 2 - 35 obese NAFLD children without fibrosis, group 3 - 18 obese children without NAFLD and fibrosis. Group 4 (control) consisted of 14 children with normal weight without NAFLD and liver fibrosis. The serum levels of vascular endothelial growth factor (VEGF) (Wuhan Fine Biotech Co Ltd, China), transforming growth factor-beta 1 (TGF-β1) (IBL International, Germany), cytokeratin-18 (CK-18) (IDL Biotech AB, Sweden) were determined by enzyme-linked immunosorbent assay (ELISA). Serum content of hydroxyproline free (HPf) and hydroxyproline protein-bound (HPp/b) according to Osadchuk and glycosaminoglycans (GAG) according to Rimington were evaluated.
Results
In 1 group children, a significant increase in the median level of CK-18 (in 2.2 times, p<0.05), VEGF (in 2.4 times, p<0.05), and TGF-β1 (in 2.7 times, p<0.05) was found compared to 4 group children. Moreover, CK-18 level was significantly higher in 1 group of patients compared to 2 group (in 1.4 times, p<0.05) and 3 group (in 1.8 times, p<0.05). In all group children, an increase in the serum HPp/b content was found: in 1 group - in 1.2 times (p<0.01), in 2 group - in 1.2 times (p<0.05), in 3 group - in 1.3 times (p<0.05) compared to 4 group. The changes in the content of hydroxyproline led to an increase in the HPp/b/HPf ratio in all groups: 1.4 times (p<0.01) in 1 and 2 groups, in 1.3 times (p<0.01) in 3 group. Also, in 1 group of children median GAG level was increased by 1.3 times (p<0.001).
In children with NAFLD HPf content negatively correlated with CAP (r= - 0.408; p<0.01), CK-18 (r=-0.469; p<0.01), the ratio HPp/b/HPf positively correlated with CAP (r=0.307; p<0.05). CK-18 positively correlated with fibrosis degree (according to METAVIR) (r=0.468; p=0.008) and liver steatosis degree (r=0.357; p=0.048). A positive correlation was also found between VEGF levels and the degree of liver fibrosis (r=0.372, p=0.036).
Conclusion
Serum levels of VEGF, TGF-β1, HPp/b, and GAG were significantly elevated in children with non-alcoholic fatty liver fibrosis. Assessment of these parameters may be useful for early diagnosis of liver fibrosis in children with NAFLD.
References
1. Schwimmer JB, Johnson JS, Angeles JE, et al. Microbiome Signatures Associated With Steatohepatitis and Moderate to Severe Fibrosis in Children With Nonalcoholic Fatty Liver Disease. Gastroenterology. 2019;157(4):1109-1122. doi:10.1053/j.gastro.2019.06.028.
2. Alkhouri N. Putting it all together: Noninvasive diagnosis of fibrosis in nonalcoholic fatty liver disease in adults and children. Clin Liver Dis (Hoboken). 2017;9(6):134-137. Published 2017 Jun 29. doi:10.1002/cld.636