Reduction of Th2 inflammation and fibrosis in eosinophilic esophagitis in a murine model by citri reticulatae pericarpium.

ETHNOPHARMACOLOGICAL RELEVANCE: Inflammation and subepithelial fibrosis play major roles in the early pathology of eosinophilic esophagitis (EoE). However, there are currently no pharmacotherapeutic interventions that directly target eosinophilic esophagitis. Citri Reticulatae Pericarpium (CRP, known as Chen-Pi) is one of most frequently used qi-regulating drugs in Chinese medicine and nutrition. CRP is rich with flavonones and polymethoxy flavones, both of which exhibit superior anti-inflammatory, anti-allergic and anti-fibrosis effects. This study is to investigate intervention effect of CRP on EoE, to identify its active compounds and to explore its underlying mechanisms. METHODS: The CRP extract was obtained by liquid-liquid extraction with 70% ethanol, and its main components were identified by HPLC and TLC chromatography as hesperidin, nobiletin, tangeretin, and narirutin in turn. Furthermore, we evaluated its effect and underlying mechanisms in an PN (Peanut protein extract)-sensitized murine model of food allergy induced EoE. RESULTS: CRP treatment attenuated EoE model mice symptomatology, blocked hypothermia, reduced the production of PN-specific IgE and IgG1 and TH2 cytokines (interleukin (IL)-4 and IL-5), and increased the level of anti-inflammatory cytokines IL-10 and interferon (IFN)-γ. CRP treatment also significantly alleviated the pathological damage and reduced fibrosis in inflamed tissues like esophagus, lung, and intestine. These results were strongly associated with reducing the expression of p-p38 mitogen-activated protein kinase (MAPK), transforming growth factor beta1 (TGF-ß1) and p-Smad 3 proteins. CONCLUSION: CRP extract markedly inhibited TH2 immune response and attenuated subepithelial fibrosis with a dose-dependent manner through down-regulating MAPK/TGF-ß signaling pathway. It is suggested that CRP extract might serve as a potential therapy for food allergy-induced EoE like disease.

Development of an Oral Isoliquiritigenin Self-Nano-Emulsifying Drug Delivery System (ILQ-SNEDDS) for Effective Treatment of Eosinophilic Esophagitis Induced by Food Allergy.

Isoliquiritigenin (ILQ) is a natural flavonoid with various pharmacological activities. In this study, we optimized the preparation method of self-nano-emulsion-loaded ILQ to further improve its bioavailability based on our previous study. In addition, its effect on the treatment of eosinophilic esophagitis was also evaluated. Combined surfactants and co-surfactants were screened, and the optimal formulation of ILQ-SNEDDS was determined according to droplet size, droplet dispersity index (DDI), and drug loading. The formulation was composed of ethyl oleate (oil phase), Tween 80 & Cremophor EL (surfactant, 7:3), and PEG 400 & 1,2-propylene glycol (cosurfactant, 1:1), with a mass ratio of 3:6:1. Its physicochemical properties, including drug loading, droplets' size, Zeta potential, appearance, and Fourier transform infrared (FTIR) spectroscopy, were characterized. In vitro release profile, in situ intestinal absorption, and in vivo pharmacokinetics were applied to confirm the improvement of oral ILQ bioavailability by NEDDS. Finally, the efficacy of ILQ-SNEDDS in the treatment of food allergy-induced eosinophilic esophagitis (EOE) was further evaluated. When the ILQ drug loading was 77.9 mg/g, ILQ-SNEDDS could self-assemble into sub-spherical uniform droplets with an average size of about 33.4 ± 2.46 nm (PDI about 0.10 ± 0.05) and a Zeta potential of approximately -10.05 ± 3.23 mV. In situ intestinal absorption showed that optimized SNEDDS significantly increased the apparent permeability coefficient of ILQ by 1.69 times, and the pharmacokinetic parameters also confirmed that SNEDDS sharply increased the max plasma concentration and bioavailability of ILQ by 3.47 and 2.02 times, respectively. ILQ-SNEDDS also significantly improved the apparent signs, allergic index, hypothermia and body weight of EoE model mice. ILQ-SNEDDS treatment significantly reduced the levels of inflammatory cytokines, such as TNF-α, IL-4, and IL-5, and the level of PPE-s-IgE in serum, and significantly inhibited the expression of TGF-ß1 in esophageal tissue. SNEDDS significantly improved the solubility and bioavailability of ILQ. Additionally, ILQ-SNEDDS treatment attenuated symptomatology of EoE model mice, which was associated with inhibiting the production of TH2 inflammatory cytokines and PPE-s-IgE and the expression of TGF-ß1. The above results shows that ILQ-SNEDDS has great potential as a good candidate for the treatment of eosinophilic esophagitis.