Diet is considered an important trigger in inflammatory bowel diseases (IBD), as feeding habits can affect intestinal permeability and clearance of bacterial antigens, consequently influencing the immune system. Free fatty acid receptors (FFARs), expressed on the intestinal epithelial cells, belong to the family of luminal-facing receptors that are responsive to nutrients. The objective of this study was to characterize the anti-inflammatory activity and the effect on intestinal barrier function of synthetic FFAR agonists in mouse models of colitis. Therapeutic activity of GW9508 (FFAR1 agonist), 4-CMTB (FFAR2 agonist), AR420626 (FFAR3 agonist), and GSK137647 (FFAR4 agonist) was investigated in two models of semi-chronic colitis: induced by trinitrobenzenesulfonic acid (TNBS), mimicking Crohn’s disease, as well as induced by dextran sulfate sodium (DSS), which recapitulates ulcerative colitis in humans. Moreover, we assessed the influence of FFARs agonists on epithelial ion transport and measured the ion flow stimulated by forskolin and veratridine. Administration of FFAR4 agonist GSK137647 attenuated both TNBS-induced and DSS-induced colitis in mice, as indicated by macroscopic parameters and myeloperoxidase activity. The action of FFAR4 agonist GSK137647 was significantly blocked by pretreatment with selective FFAR4 antagonist AH7614. Moreover, FFAR1 and FFAR4 agonists reversed the increase in the colon permeability caused by inflammation. FFAR4 restored the tight junction genes expression in mouse colon. This is the first evaluation of the anti-inflammatory activity of selective FFAR agonists, showing that pharmacological intervention targeting FFAR4, which is a sensor of medium and long chain fatty acids, attenuates intestinal inflammation.

Background: The negative impact of a high-fat diet on the course of gastroesophageal reflux disease (GERD) has been previously reported. Free fatty acid receptors (FFARs) may be mediators of this phenomenon. The aim of this study was to characterize the role of FFARs in the course of nonerosive (NERD) and erosive (ERD) reflux disease. Methods: Collectively, 73 patients (62 with GERD and 11 healthy controls (HCs)) were recruited to the study. Esophageal biopsies were drawn from the lower third of the esophagus and kept for further experiments. Quantitative, real-time polymerase chain reaction was used to assess the expression of FFAR1, FFAR2, FFAR3, and FFAR4 in biopsies. Histological evaluation of dilated intracellular spaces (DISs) was also performed. Results: FFAR3 exhibited the highest expression, and FFAR4 exhibited the lowest expression in all esophageal samples. Higher relative expression of FFAR1 and FFAR2 and significantly higher expression of FFAR3 (p = 0.04) was noted in patients with GERD compared to respective HCs. Patients with nonerosive GERD (NERD) presented higher expression of all FFARs compared to patients with erosive GERD (ERD) and respective HCs. Interestingly, in patients with ERD, the expression of FFAR3 was lower than in HCs. Significant, weak, positive correlation was found for FFAR3 and FFAR4 expression and DIS scores (r = 0.36, p < 0.05 for FFAR 3, and r = 0.39, p < 0.05 for FFAR4). Conclusions: In this study, we show that FFARs may play a role in GERD pathogenesis, particularly in the NERD type. It may be assumed that FFARs, in particular FFAR3 and FFAR4, may have diagnostic and therapeutic potential in GERD.

Colorectal cancer (CRC) is among the three most commonly diagnosed malignancies worldwide and remains a major public health challenge, emphasizing the need for effective preventive strategies. Considering the current chemotherapy limitations of key agents, natural products widely researched as dietary supplements can complement conventional treatments. This review concentrates on Aronia melanocarpa (black chokeberry), including its fruits, leaves and pomace, as a rich source of bioactive compounds with well-documented anticancer properties. Notably, A. melanocarpa contains high levels of polyphenols such as cyanidin-3-galactoside, cyanidin-3-arabinoside, chlorogenic acid, quercetin, and epicatechin, as well as biologically active polysaccharides, including pectins and arabinogalactans. These compounds, through their antioxidant and anti-inflammatory activities, are involved in modulating apoptosis pathways specifically targeting cancer cells. Moreover, their complexes may enhance chemopreventive efficacy through synergistic mechanisms. Recent studies show that supplementation with aronia products can improve inflammatory markers such as interleukin-6 and tumor necrosis factor alpha, highlighting its potential role in modulating the tumor microenvironment. Collectively, these findings position A. melanocarpa as a promising candidate for use in integrative strategies aimed at the prevention and adjunctive treatment of CRC.

The treatment of inflammatory bowel diseases (IBDs), particularly ulcerative colitis and Crohn’s disease, remains a challenge. As the available therapeutic options have limited efficacy and various side effect, there is a need to identify new inflammatory modulators that can influence IBD. Natural polyphenols and polyphenol-rich extracts have been found to have preventive and therapeutic potential, including various anti-inflammatory effects. In this study, the inhibition of the formation of mediators associated with intestinal inflammation, remodelling, and angiogenesis by the spent hop extract (SHE), a polyphenol-rich extract from Humulus lupulus L., and its flaxseed polysaccharide-based encapsulates was examined using tumour necrosis factor alpha (TNF-α)-stimulated human small intestinal epithelial (HIEC-6) and large intestinal epithelial (CCD841CoN) cells. Also, we assessed the activity of the tested agents after in the vitro-simulated gastrointestinal digestion process. SHE strongly inhibited the expression of pro-inflammatory cytokines, mainly IL-1β and TNF-α, as well as the expression and activity of type IV collagenases (MMP-2 and MMP-9); these effects resulted from the suppression of NF-κB, ERK and Akt signalling pathways. We also proved the protective effect of encapsulation process against the reduction in the bioaccessibility of SHE, observed under the influence of digestion process. Our results provide initial evidence on the potential utility of SHE and its encapsulates in IBD.

Background: Recent studies suggest that lipids, including free fatty acids (FFAs), are necessary for proper μ opioid receptor (MOR) binding and that activation of opioid receptors (ORs) improves intestinal inflammation. The objective of the study was to investigate a possible interaction between the ORs and FFA receptors (FFARs) ligands in the colitis. Methods: The potential synergistic effect of ORs and FFARs ligands was evaluated using mouse model of acute colitis induced by dextran sulfate sodium (DSS, 4%). Compounds were injected intraperitoneally (i.p.) once or twice daily at the doses of 0.01 or 0.02 mg/kg body weight (BW) (DAMGO—an MOR agonist), 0.3 mg/kg BW (DPDPE—a δ OR (DOR) agonist) and 1 mg/kg BW (naloxone—a non-selective OR antagonist, GLPG 0974—a FFAR2 antagonist, GSK 137647—a FFAR4 agonist and AH 7614—a FFAR4 antagonist) for 4 days. Results: Myeloperoxidase (MPO) activity was significantly decreased after DAMGO (0.02 mg/kg BW) and GSK 137647 (1 mg/kg BW) administration and co-administration as compared to DSS group. Conclusions: Treatment with ligands of ORs and FFARs may affect the immune cells in the inflammation; however, no significant influence on the severity of colitis and no synergistic effect were observed.