Caffeic Acid Phenethyl Ester Attenuates Dextran Sulfate Sodium-Induced Ulcerative Colitis Through Modulation of NF-κB and Cell Adhesion Molecules

The antioxidant property of CAPE depends on TRPV1 channel activation in microvascular endothelial cells

Caffeic acid phenethyl ester (CAPE) is a hydrophobic phytochemical typically found in propolis that acts as an antioxidant, anti-inflammatory and cardiovascular protector, among several other properties. However, the molecular entity responsible for recognising CAPE is unknown, and whether that molecular interaction is involved in developing an antioxidant response in the target cells remains an unanswered question. Herein, we hypothesized that a subfamily of TRP ion channels works as the molecular entity that recognizes CAPE at the plasma membrane and allows a fast shift in the antioxidant capacity of intact endothelial cells (EC). By monitoring cytoplasmic Ca2+ in a microvascular EC model, we compared the calcium responses evoked by three structurally related compounds: caffeic acid phenethyl ester, neochlorogenic acid and caffeic acid. Only CAPE induced rapid and transient calcium responses at nanomolar concentrations together with a gradual increase in cytoplasmic sodium levels, suggesting the activation of a non-selective cationic permeation at the plasma membrane. Electrophysiological as well as pharmacological, and RNA silencing assays confirmed the involvement of TRPV1 in the recognition of CAPE by ECs. Finally, we demonstrated that Ca2+ influx by TRPV1 was necessary for recording CAPE-induced cytoplasmic redox changes, a phenomenon captured in real-time in ECs expressing the HyPer biosensor. Our data depict a molecular mechanism behind the antioxidant effect of CAPE in endothelial cells, connecting the activation of TRPV1 ion channels, cytoplasmic calcium increase, and a reduction of disulfide bonds on a redox biosensor. This phenomenon occurs within seconds to minutes and contributes to a better understanding of the mechanisms underlying the vasodilatory effect of CAPE and other compounds that interact with TRPV1 in the vascular bed.

Genetically Predicted Higher Levels of Caffeic Acid Are Protective Against Ulcerative Colitis: A Comprehensive Metabolome Analysis

BACKGROUND

It is crucial to pinpoint the metabolites that cause Crohn's disease (CD) and ulcerative colitis (UC) to comprehend their pathogenesis and identify possible targets for therapy. To achieve this goal, we performed the first metabolome-wide Mendelian randomization (MR) study of Japanese patients with CD and UC.

METHODS

As exposure datasets, genetic instruments with blood-circulating metabolites were obtained from the Tohoku Medical Megabank Organization, which includes 204 metabolites from the genome-wide association study data of 7843 Japanese individuals. As outcome datasets, we enrolled Japanese patients with CD (n = 1803), Japanese patients with UC (n = 1992), and healthy controls (n = 2022). The main analysis utilized the inverse variance-weighted method, while stability of the findings was evaluated through sensitivity analyses.

RESULTS

After single nucleotide polymorphism (SNP) filtering, 169 SNPs for 45 metabolites were available for MR. Genetically predicted elevated circulating trans-glutaconic acid and tryptophan were associated with a lower CD risk (odds ratio [OR], 0.68; P = 5.95 × 10-3; and OR, 0.64; P = 1.90 × 10-2, respectively). Genetically predicted elevated caffeic acid was associated with a lower UC risk (OR, 0.67; P = 4.2 × 10-4), which remained significant after multiple testing correction. We identified a causal link between UC and 3-hydroxybutyrate (OR, 2.21; P = 1.41 × 10-2), trans-glutaconic acid (OR, 0.72; P = 1.77 × 10-2), and 2-hydroxyvaleric acid (OR, 1.31; P = 4.23 × 10-2). There was no evidence of pleiotropy or reverse causal effects for these candidate metabolites.

CONCLUSIONS

In our metabolome-wide MR study, we discovered a notable protective effect of caffeic acid against UC.

Nrf2-mediated ferroptosis inhibition: a novel approach for managing inflammatory diseases

Inflammatory diseases, including psoriasis, atherosclerosis, rheumatoid arthritis, and ulcerative colitis, are characterized by persistent inflammation. Moreover, the existing treatments for inflammatory diseases only provide temporary relief by controlling symptoms, and treatments of unstable and expensive. Therefore, new therapeutic solutions are urgently needed to address the underlying causes or symptoms of inflammatory diseases. Inflammation frequently coincides with a high level of (reactive oxygen species) ROS activation, serving as a fundamental element in numerous physiological and pathological phenotypes that can result in serious harm to the organism. Given its pivotal role in inflammation, oxidative stress, and ferroptosis, ROS represents a focal node for investigating the (nuclear factor E2-related factor 2) Nrf2 pathway and ferroptosis, both of which are intricately linked to ROS. Ferroptosis is mainly triggered by oxidative stress and involves iron-dependent lipid peroxidation. The transcription factor Nrf2 targets several genes within the ferroptosis pathway. Recent studies have shown that Nrf2 plays a significant role in three key ferroptosis-related routes, including the synthesis and metabolism of glutathione/glutathione peroxidase 4, iron metabolism, and lipid processes. As a result, ferroptosis-related treatments for inflammatory diseases have attracted much attention. Moreover, drugs targeting Nrf2 can be used to manage inflammatory conditions. This review aimed to assess ferroptosis regulation mechanism and the role of Nrf2 in ferroptosis inhibition. Therefore, this review article may provide the basis for more research regarding the treatment of inflammatory diseases through Nrf2-inhibited ferroptosis.

Repurposing metformin as adjuvant therapy in patients with ulcerative colitis treated with mesalamine: A randomized controlled double-blinded study

BACKGROUND

Ulcerative colitis (UC) is a type of inflammatory bowel disease associated with persistent inflammation. Animal studies proved the efficacy of metformin in UC.

AIM

To investigate the potential role of metformin and its protective pathways in patients with UC.

METHODS

This is a randomized, controlled, and double-blinded clinical trial that included 60 participants with mild to moderate UC and was divided randomly into two groups (n = 30). For 6 months, the mesalamine group received 1 g of mesalamine three times daily (t.i.d.). For six months, the metformin group received mesalamine 1 g t.i.d. and metformin 500 mg twice daily. A gastroenterologist evaluated patients at baseline and 6 months after starting the treatment in order to measure serum levels of zonulin, sphingosine 1 phosphate (S1P), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α). Biopsies from the colon were used to measure gene expression of zonula occuldin-1 (ZO-1), signal transducer and activator of factor-3 (STAT-3), and intracellular adhesion molecule-1 (ICAM-1). The numeric pain rating scale (NRS) and partial Mayo score were also assessed for each patient.

RESULTS

When compared to the mesalamine group, the metformin group demonstrated a statistical decrease in serum IL-6, zonulin, TNF-α, SIP, gene expression of ICAM-1 and STAT-3, and a significant increase in colonic ZO-1 when compared to the mesalamine group. The metformin group also showed a significant decrease in NRS and partial Mayo score index in comparison with the mesalamine group.

CONCLUSION

Metformin may be a promising additional therapy for UC patients. Trial registration identifier: NCT05553704.

Integrative analysis revealed the role of glucagon-like peptide-2 in improving experimental colitis in mice by inhibiting inflammatory pathways, regulating glucose metabolism, and modulating gut microbiota

Introduction

Ulcerative colitis (UC) is an inflammatory bowel disease characterized by recurrent and remitting inflammation of the mucosa of the colon and rectum, the incidence of which is on the rise. Glucagon-like peptide-2 (GLP-2) is a newly discovered neurotrophic factor, but its efficacy and mechanism of action in UC remain unclear. In this study, we investigated the protective effects and potential targets of GLP-2 on dextran sodium sulfate (DSS)-induced UC in mice through integrative analysis.

Methods

The effects of GLP-2 on UC were assessed by calculating the disease activity index, colonic mucosal damage index, and pathological histological scores. Enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry were used to detect the expression of GLP-2, nuclear factor kappa-B (NF-κB), interleukin-6 (IL-6), and signal transducer and activator of transcription-3 (STAT3). The 16SrRNA gene was used to detect changes in gut microbiota in mouse colonic tissues, and oral glucose tolerance test (OGTT) blood glucose levels were used to analyze the differences in flora.

Results

The results showed that GLP-2 could reduce the inflammation of UC mice, which may be achieved by inhibiting the potential targets of NF-κB, and Janus kinase (JAK)/STAT3 inflammatory pathways, regulating sugar metabolism, increasing dominant species, and improving microbial diversity.

Discussion

This study provides new insight into the potential of GLP-2 for achieving more ideal UC treatment goals in future.

Caffeic Acid Phenethyl Ester Loaded PEG-PLGA Nanoparticles Enhance Wound Healing in Diabetic Rats

Delayed wound healing is a serious complication of diabetes and a main reason for foot amputation. Caffeic acid phenethyl ester (CAPE) is a main active constituent of honeybee propolis with reported appealing pharmacological activities. In the current study, CAPE was loaded onto PEG-PLGA nanoparticles and showed a particle size of 198 ± 7.3 nm and polydispersity index of 0.43 ± 0.04. An in vivo study was performed to appraise the wound-healing activity of CAPE-loaded PEG-PLGA nanoparticles (CAPE-NPs) in diabetic rats. Wound closure was significantly accelerated in rats treated with CAPE-NPs. This was confirmed via histological examinations of skin tissues that indicated expedited healing and enhanced collagen deposition. This was accompanied by observed antioxidant activity as evidenced by the prevention of lipid peroxidation and the exhaustion of superoxide dismutase (SOD) and catalase (CAT) activities. In addition, CAPE-NPs showed superior anti-inflammatory activity as compared with the regular formula of CAPE, as they prevented the expression of interleukin-6 (IL-6) as well as tumor necrosis-alpha (TNF-α). The pro-collagen actions of CAPE-NPs were highlighted by the enhanced hyroxyproline content and up-regulation of Col 1A1 mRNA expression. Furthermore, the immunohistochemial assessment of skin tissues indicated that CAPE-NPs enhance proliferation and angiogenesis, as shown by the increased expression of transforming growth factor β1 (TGF-β1) and platelet-derived growth factor subunit B (PDGF-B). In conclusion, CAPE-loaded PEG-PLGA nanoparticles possess potent healing effects in diabetic wounds. This is mediated, at least partially, by its antioxidant, anti-inflammatory, and pro-collagen as well as angiogenic activities.

A Nano-Liposomal Formulation of Caffeic Acid Phenethyl Ester Modulates Nrf2 and NF-κβ Signaling and Alleviates Experimentally Induced Acute Pancreatitis in a Rat Model

The currently available management strategies for acute pancreatitis are inadequately effective which calls for exploration of new approaches to treat this condition. Caffeic acid phenethyl ester (CAPE) is a major bioactive constituent of honeybee propolis with promising therapeutic and preventive applications. However, its pharmaceutical potential and clinical use are hindered by its poor water solubility and limited plasma stability. In this study, we aimed to prepare, characterize and evaluate a CAPE-loaded nanoliposomal formulation to improve the efficacy of CAPE for the management of acute pancreatitis. The CAPE-loaded nanoliposomes (CAPE-loaded-NL) were prepared by a thin layer evaporation technique and were optimized using three edge activators. CAPE-loaded-NL were characterized for their vesicle size (VS), zeta potential (ZP), encapsulation efficiency (EE), polydispersity index (PDI), crystalline state and morphology. The protective effect of the optimal CAPE-loaded-NL was evaluated in a rat model of acute pancreatitis induced by administering a single intraperitoneal injection of L-ornithine. Oral pretreatment with CAPE-loaded-NL significantly counteracted ornithine-induced elevation in serum activities of pancreatic digestive enzymes and pancreatic levels of malondialdehyde, nuclear factor kappa B (NF-κB) p65, tumor necrosis factor-alpha, nitrite/nitrate, cleaved caspase-3 and myeloperoxidase activity. Moreover, pretreatment with CAPE-loaded-NL significantly reinstated the ornithine-lowered glutathione reductase activity, glutathione, nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 levels and ATP/ADP ratio, and potentiated the Bcl-2/Bax ratio in pancreatic tissue. CAPE-loaded-NL displayed superior antioxidant, anti-inflammatory and anti-apoptotic effects compared to free CAPE oral suspension and achieved a more potent correction of the derangements in serum amylase and pancreatic myeloperoxidase activities. The histological observations were in line with the biochemical findings. Our results suggest that CAPE-loaded-NL provide a promising interventional approach for acute pancreatitis mainly through the enhancement of the exerted antioxidant, anti-inflammatory and anti-apoptotic effects which may be mediated, at least in part, through modulation of Nrf2 and NF-κβ signaling.

Pharmacological Effects of Polyphenol Phytochemicals on the Intestinal Inflammation via Targeting TLR4/NF-κB Signaling Pathway

TLR4/NF-κB is a key inflammatory signaling transduction pathway, closely involved in cell differentiation, proliferation, apoptosis, and pro-inflammatory response. Toll like receptor 4 (TLR4), the first mammalian TLR to be characterized, is the innate immune receptor that plays a key role in inflammatory signal transductions. Nuclear factor kappa B (NF-κB), the TLR4 downstream, is the key to accounting for the expression of multiple genes involved in inflammatory responses, such as pro-inflammatory cytokines. Inflammatory bowel disease (IBD) in humans is a chronic inflammatory disease with high incidence and prevalence worldwide. Targeting the TLR4/NF-κB signaling pathway might be an effective strategy to alleviate intestinal inflammation. Polyphenol phytochemicals have shown noticeable alleviative effects by acting on the TLR4/NF-κB signaling pathway in intestinal inflammation. This review summarizes the pharmacological effects of more than 20 kinds of polyphenols on intestinal inflammation via targeting the TLR4/NF-κB signaling pathway. We expected that polyphenol phytochemicals targeting the TLR4/NF-κB signaling pathway might be an effective approach to treat IBD in future clinical research applications.