Page 73 - Petelin, Ana, ur. 2024. Zdravje delovno aktivnih in starejših odraslih / Health of Working-Age and Older Adults. Zbornik povzetkov z recenzijo ▪︎ Book of Abstracts. Koper: Založba Univerze na Primorskem/University of Primorska Press

Effect of Helichrysum italicum infusion on intestinal barrier permeability
and translocation of Salmonella Infantis

Katja Kramberger, Katja Kranjc, Darja Barlič-Maganja, Saša Kenig, Zala Jenko Pražnikar
University of Primorska, Faculty of Health Sciences, Izola, Slovenia

Introduction: Chronic systemic inflammation and gut dysbiosis, conditions observed
in obesity and other chronic diseases, affect the function of the intestinal barrier (IB).
Both conditions are characterized by increased IB permeability, which is associated
with the translocation of bacteria. Bacterial translocation, which denotes the passage
of viable bacteria from the gut to extraintestinal sites, can lead to the development of
systemic inflammatory conditions and thus further promotes chronic inflammation.
Dietary components, including probiotics, polyphenols, lipids, and proteins can im-
prove IB function by either suppressing inflammation or by acting directly on IB. Heli-
chrysum italicum is an aromatic Mediterranean herb rich in polyphenolic compounds.
In our previous studies, we have already demonstrated anti-inflammatory effects of H.
italicum infusion (HII), whereas the results from a transcriptome analysis of intestinal
cells have shown potential effects on the integrity of the IB. In the present study, we
aimed to confirm the effect of HII on the IB via altering the expression of tight junc-
tion proteins. Additionally, we evaluated its effects on transepithelial electrical resist-
ance (TEER) and the adhesion, invasion and translocation capacity of Salmonella In-
fantis. Methods: Caco-2 intestinal epithelial cells cultured on the porous membrane of
Transwell inserts were used as a model for the permeability of the IB. The integrity
of the cell monolayer was verified by TEER measurements before and after all treat-
ments. Inflammation in cells incubated with or without HII was induced by heat-killed
(HKB) or live S. Infantis bacteria. Following treatment, isolated RNA was reverse tran-
scribed into complementary DNA, and gene expression of selected tight junction pro-
teins was analysed by real-time polymerase chain reaction (RT-PCR). To determine
the number of translocated S. Infantis bacteria, the media from basolateral compart-
ment was sampled after incubation and serial dilutions were plated on tryptic soy agar.
Results: 24-hour treatment with HKB reduced TEER of Caco-2 cells by 60.0%, while
co-treatment together with HII (0.2 v/v%) resulted in a 51.3% reduction (p=0.0284).
Pre-treatment with HII for 24 h had no effect on TEER per se, but when followed by
24-hour HKB treatment, cells pre-treated with HII had almost 10% lower decrease in
TEER compared to non-pre-treated cells (p=0.0034). Additionally, 24-hour pre-treat-
ment with HII (0.2 v/v%) prevented the translocation of S. Infantis bacteria across the prehrana in zdravje delovno aktivnih in starejših odraslih | nutrition and health of working-age and older adults
cell monolayer by 95%. However, after a 2-hour bacterial infection no significant differ-
ences in TEER were observed between experiments.
Discussion and conclusions: Measurements of the epithelial integrity of Caco-2 cell
showed that the HII can improve the HKB-disrupted IB integrity. The latter was con-
firmed by altering the expression of tight junction genes. Pre-treatment with HII also
prevented translocation of S. Infantis. The results of our study suggest an important
role of HII in maintaining the integrity of the IB, especially in inflammatory conditions.
Keywords: Helichrysum italicum, intestinal barier integrity, tight junctions, inflammation,
translocation, Salmonella Infantis

73