Polydatin attenuated food allergy via store-operated calcium channels in mast cell

Palmitoylethanolamide and polydatin in pediatric irritable bowel syndrome: A multicentric randomized controlled trial

OBJECTIVE

This study aimed to evaluate the efficacy and safety of co-micronized palmitoylethanolamide (PEA)/polydatin (PD) in the treatment of abdominal pain symptoms in pediatric patients with irritable bowel syndrome (IBS).

METHODS

This was a multicenter trial conducted at three Italian pediatric gastroenterology centers, employing a double-blind, placebo-controlled, parallel-arm design. Participants were ages 10 to 17 y and met Rome IV criteria for pediatric IBS. They were randomly allocated to receive either co-micronized PEA/PD or placebo, administered three times daily in a 1:1 ratio, over a 12-wk period. The study assessed baseline severity using the IBS-Severity Scoring System (IBS-SSS) at enrollment and after 4, 8, and 12 wk of treatment. Abdominal pain frequency was assessed on a scale from 1 to 7 d/wk, while stool consistency was classified using the Bristol Stool Scale (BSS) to categorize various IBS subtypes. The primary outcome was the percentage of patients who achieved complete remission, defined as IBS-SSS score <75 points after 12 wk of therapy.

RESULTS

The study involved 70 children with IBS. Of the participants, 34 received co-micronized PEA/PD, and 36 received a placebo. As compared with the placebo group, the co-micronized therapy group had significantly more patients achieving complete remission after 12 wk (P = 0.015), with particular benefit in the IBS-diarrhea subtype (P = 0.01). The treatment group also experienced a significant reduction in abdominal pain intensity and frequency compared with the placebo group. No adverse events were recorded during the study period.

CONCLUSIONS

Co-micronized PEA/PD is a safe and effective treatment to treat abdominal pain symptoms in pediatric IBS.

Polydatin ameliorates low-density lipoprotein cholesterol and lipid metabolism by downregulating proprotein convertase subtilisin/kexin type 9 (PCSK9) in triple-negative breast cancer with hyperlipidemia

To investigate polydatin's effects on low-density lipoprotein cholesterol (LDL-C) and lipid metabolism in mice with triple-negative breast cancer (TNBC) and hyperlipidemia, as well as the underlying mechanism of proprotein convertase subtilisin/kexin type 9 (PCSK9). In vivo, we designed two animal models, namely breast pad in situ inoculation of TNBC model and TNBC with lung metastatic were inoculated with the caudal vein model. Mice were administered a high-fat diet. Upon the completion of the experiment, plasma triglycerides (TG), total plasma cholesterol (TC), plasma LDL-C, and plasma high-density lipoprotein cholesterol (HDL-C) were measured. ELISA was employed to measure PCSK9 and the low-density lipoprotein receptor (LDLR). The morphological alterations were observed using Oil-red O staining. Immunohistochemical labeling was used to determine the expression of PCSK9 and LDLR in mouse breast cancer (BC) tissues. MTT, wound healing assay, and the transwell migration and invasion test were conducted to examine co-cultured adipocytes' effects on the growth, invasion, and migration of BC cells. In the 4T1-luc cell model injected in situ into the breast pad and 4T1-luc cell model injected into the tail vein, we observed that a high-fat diet promoted the proliferation and lung metastasis of BC cells, whereas polydatin suppressed the proliferation and lung metastasis of BC cells. Co-culture of BC cells with adipocytes enhanced the proliferation, invasion, and metastasis, while polydatin intervention inhibited the growth, invasion, and metastasis. After treatment with polydatin, serum lipid levels decreased, PCSK9 decreased, LDLR increased, and LDL-C decreased in mouse BC, liver, and lung tissues. After polydatin treatment, PCSK9 decreased, LDLR increased, and LDL-C decreased in an in vitro co-culture system of BC cells and adipocytes. After transfection of siRNA PCSK9 in the co-culture system, the LDLR increased more significantly, and the LDL-C decreased more significantly. After transfection of LV-PCSK9, PCSK9 decreased, LDLR increased, and LDL-C decreased. We concluded that polydatin inhibited breast tumor proliferation and distant lung metastasis in mice promoted by a high lipid environment. By suppressing PCSK9, polydatin alters the lipid profile of hyperlipidemic TNBC mice and prevents distant metastases. Our findings provide credence to the established practice of using polydatin in treating TNBC combined with hyperlipidemia.

Polydatin radiosensitizes lung cancer while preventing radiation injuries by modulating tumor-infiltrating B cells

BACKGROUND

Acquired radio-resistance and the undesired normal tissue radiation injuries seriously discount the therapeutic effect of lung cancer radiotherapy. In this study, we aimed to explore the role and potential mechanism of polydatin in simultaneously decreasing radioresistance and radiation injuries.

METHODS

The tumor-bearing model of nude mice was used to investigate the tumor inhibition of polydatin on lung cancer and its effect on radiosensitivity, and the effect of polydatin on B cell infiltration in cancerous tissue was investigated. In addition, we performed systemic radiotherapy on BABL/C mice and evaluated the protective effect of polydatin on radiation injury by the Kaplan-Meier survival curve. Moreover, the regulation of polydatin on proliferation and apoptosis of A549 cells was also investigated in vitro.

RESULTS

In this study, it is first found that polydatin inhibits the growth and promotes the radiosensitivity of lung cancer while reducing the radiation damage of the healthy tissue. Further, it is evidenced that the major mechanism relies on its regulation on body's immune function, and in particular, the inhibition of radiation-induced B cell infiltration in tumor tissue.

CONCLUSION

These findings show that in addition to tumor inhibition, polydatin also promotes the sensitivity and reduces the adverse reactions of radiotherapy, making itself a promising candidate for boosting lung cancer radiotherapy efficacy.

Development of gastro-food allergy model in shrimp allergen extract-induced sensitized mice promotes mast cell degranulation

Background: Food allergies have become more common in the last decade. Shrimp is one of the most dominant food allergy triggers in Asian countries, including Indonesia. After ingesting allergens, B cells will produce allergen-specific Immunoglobin E (IgE). In the sensitization period, repeated allergen exposure promotes Mast Cell (MC) degranulation in intestinal tissue and releases several inflammatory mediators, thereby causing hypersensitivity reactions. Shrimp Allergen Extract (SAE) is an immunotherapy and diagnostic agent currently being developed in Indonesia. In this study, we investigated the effect of SAE administration on eliciting an MC immunological response. Methods: Mice were divided into a non-sensitized and sensitized group. The non-sensitized group only received 1 mg of alum (i.p), whereas the sensitized group received 1 mg of alum and 100 μg of SAE on days 0, 7, and 14. Then, both groups were challenged with 400 μg SAE (p.o) on days 21, 22, and 23 following systemic allergic symptom observation. Results: We showed that SAE was able to increase systemic allergic symptoms significantly in the sensitized mice through repeated challenge (1.33±0.21; 1.83±0.17; and 2.00±0.00), compared to non-sensitized mice (0.17±0.17). Moreover, histopathological analysis showed that the SAE administration causes an increase of MC degranulation in the ileum tissue of the sensitized mice (44.43%±0.01), compared to non-sensitized mice (35.45%±0.01) Conclusions: This study found that SAE could induce allergic reactions in mice by influencing critical effector cells, MCs.

Polydatin: Pharmacological Mechanisms, Therapeutic Targets, Biological Activities, and Health Benefits

Polydatin is a natural potent stilbenoid polyphenol and a resveratrol derivative with improved bioavailability. Polydatin possesses potential biological activities predominantly through the modulation of pivotal signaling pathways involved in inflammation, oxidative stress, and apoptosis. Various imperative biological activities have been suggested for polydatin towards promising therapeutic effects, including anticancer, cardioprotective, anti-diabetic, gastroprotective, hepatoprotective, neuroprotective, anti-microbial, as well as health-promoting roles on the renal system, the respiratory system, rheumatoid diseases, the skeletal system, and women's health. In the present study, the therapeutic targets, biological activities, pharmacological mechanisms, and health benefits of polydatin are reviewed to provide new insights to researchers. The need to develop further clinical trials and novel delivery systems of polydatin is also considered to reveal new insights to researchers.

Peanut allergen induces more serious allergic reactions than other allergens involving MAPK signaling pathways

There is no universally accepted uniform research to classify the severity of allergic reactions triggered by different food allergens. We established a food allergy model based on repeated intragastric administrations of proteins from peanut, egg, milk, or soybean mixed with cholera toxin followed by oral food challenges with a high dose of the sensitizing proteins. Increased specific IgE, specific IgG1, allergic symptom scores, histamine, murine mast cell proteases-1, vascular leakage, Th2 cytokines, and mast cell infiltration in the lungs and intestine were found in the allergic groups via enzyme-linked immunosorbent assay, hematoxylin-eosin, and toluidine blue staining. Each sensitized group showed a decrease in body temperature and Th1 cytokines after oral food challenge. The increased levels of Th2 cytokines, IL-25, IL-33, and TSLP, and related asthma genes ARG1, DCN, LTB4R1 and NFKBIA as well as the activation of MAPK signaling pathways were also revealed by quantitative real-time PCR and western blotting. In terms of the severity of food allergies, peanut allergy was the most serious followed by egg and milk, and soybean allergy was the least severe. Compared to other allergic groups, asthma genes were regulated through the MAPK signaling pathways to produce related Th2 cytokines in peanut allergy; consequently, mice in the peanut group exhibited more severe allergic reactions. Comparison of the severity of food allergies is required for the development of milder prevention for severe food allergies.

Polydatin as a therapeutic alternative for central nervous system disorders: A systematic review of animal studies

Polydatin, or piceid, is a natural stilbene found in grapes, peanuts, and wines. Polydatin presents pharmacological activities, including neuroprotective properties, exerting preventive and/or therapeutic effects in central nervous system (CNS) disorders. In the present study, we summarize and discuss the neuroprotective effects of polydatin in CNS disorders and related pathological conditions in preclinical animal studies. A systematic review was performed by searching online databases, returning a total of 110 records, where 27 articles were selected and discussed here. The included studies showed neuroprotective effects of polydatin in experimental models of neurological disorders, including cerebrovascular disorders, Parkinson's disease, traumatic brain injuries, diabetic neuropathy, glioblastoma, and neurotoxicity induced by chemical agents. Most studies were focused on stroke (22.2%) and conducted in male rodents. The intervention protocol with polydatin was mainly acute (66.7%), with postdamage induction treatment being the most commonly used regimen (55.2%). Overall, polydatin ameliorated behavioral dysfunctions and/or promoted neurological function by virtue of its antioxidant and antiinflammatory properties. In summary, this review offers important scientific evidence for the neuroprotective effects and distinct pharmacological mechanisms of polydatin that not only enhances the present understanding but is also useful for the development of future preclinical and clinical investigations.

Calcium Ions Aggravate Alzheimer's Disease Through the Aberrant Activation of Neuronal Networks, Leading to Synaptic and Cognitive Deficits

Alzheimer’s disease (AD) is a neurodegenerative disease that is characterized by the production and deposition of β-amyloid protein (Aβ) and hyperphosphorylated tau, leading to the formation of β-amyloid plaques (APs) and neurofibrillary tangles (NFTs). Although calcium ions (Ca²⁺) promote the formation of APs and NFTs, no systematic review of the mechanisms by which Ca²⁺ affects the development and progression of AD has been published. Therefore, the current review aimed to fill the gaps between elevated Ca²⁺ levels and the pathogenesis of AD. Specifically, we mainly focus on the molecular mechanisms by which Ca²⁺ affects the neuronal networks of neuroinflammation, neuronal injury, neurogenesis, neurotoxicity, neuroprotection, and autophagy. Furthermore, the roles of Ca²⁺ transporters located in the cell membrane, endoplasmic reticulum (ER), mitochondria and lysosome in mediating the effects of Ca²⁺ on activating neuronal networks that ultimately contribute to the development and progression of AD are discussed. Finally, the drug candidates derived from herbs used as food or seasoning in Chinese daily life are summarized to provide a theoretical basis for improving the clinical treatment of AD.

Polydatin Attenuates OGD/R-Induced Neuronal Injury and Spinal Cord Ischemia/Reperfusion Injury by Protecting Mitochondrial Function via Nrf2/ARE Signaling Pathway

Spinal cord ischemia/reperfusion injury (SCII) is a devastating complication of spinal or thoracic surgical procedures and can lead to paraplegia or quadriplegia. Neuronal cell damage involving mitochondrial dysfunction plays an important role in the pathogenesis of SCII. Despite the availability of various treatment options, there are currently no mitochondria-targeting drugs that have proven effective against SCII. Polydatin (PD), a glucoside of resveratrol, is known to preserve mitochondrial function in central nervous system (CNS) diseases. The aim of the present study was to explore the neuro- and mito-protective functions of PD and its underlying mechanisms. An in vitro model of SCII was established by exposing spinal cord motor neurons (SMNs) to oxygen–glucose-deprivation/reperfusion (OGD/R), and the cells were treated with different dosages of PD for varying durations. PD improved neuronal viability and protected against OGD/R-induced apoptosis and mitochondrial injury in a dose-dependent manner. In addition, PD restored the activity of neuronal mitochondria in terms of mitochondrial membrane potential (MMP), intracellular calcium levels, mitochondrial permeability transition pore (mPTP) opening, generation of reactive oxygen species (ROS), and adenosine triphosphate (ATP) levels. Mechanistically, PD downregulated Keap1 and upregulated Nrf2, NQO-1, and HO-1 in the OGD/R-treated SMNs. Likewise, PD treatment also reversed the neuronal and mitochondrial damage induced by SCII in a mouse model. Furthermore, the protective effects of PD were partially blocked by the Nrf2 inhibitor. Taken together, PD relieves mitochondrial dysfunction-induced neuronal cell damage by activating the Nrf2/ARE pathway and is a suitable therapeutic option for SCII.

Store-Operated Calcium Entry via STIM1 Contributes to MRGPRX2 Induced Mast Cell Functions

Mast cells are inflammatory immune cells that play an essential role in mediating allergic reactions in humans. It is well-known that mast cell activation is critically regulated by intracellular calcium ion (Ca²⁺) concentrations. MAS-related G-protein coupled receptor-X2 (MRGPRX2) is a G-protein coupled receptor (GPCR) expressed on mast cells that is activated by various ligands, including several FDA approved drugs; consequently, this receptor has been implicated in causing pseudo-allergic reactions in humans. MRGPRX2 activation leads to an increase in intracellular Ca²⁺ levels; however, the Ca²⁺ mobilizing mechanisms utilized by this receptor are largely unknown. Previous reports showed that store-operated Ca²⁺ entry (SOCE) via the calcium sensor, stromal interaction molecule 1 (STIM1), regulates mast cell response induced by the high-affinity IgE receptor (FcεRI). In this study, using complementary pharmacologic and genetic ablation approaches we demonstrate that SOCE through STIM1 promotes MRGPRX2-induced human mast cell response in vitro. Importantly, SOCE also critically modulates MrgprB2 (mouse ortholog of human MRGPRX2) dependent inflammation in in vivo mouse models of pseudo-allergy. Collectively, our data suggests that MRGPRX2/MrgprB2 activation of mast cells is dependent on SOCE via STIM1, and further characterization of the MRGPRX2-SOCE-STIM1 pathway will lead to the identification of novel targets for the treatment of pseudo-allergic reactions in humans.

Imperatorin alleviates ROS-mediated airway remodeling by targeting the Nrf2/HO-1 signaling pathway

In this study, we investigated the role and mechanism of imperatorin (IMP) in chronic inflammation and airway remodeling. The levels of TNF-α, IL-1β, IL-6, IL-8, VEGF, α-SMA, and ROS were detected by ELISA, immunohistochemistry (IHC), immunofluorescence, and Western blot. In addition, we evaluated the effect of IMP on MAPK, PI3K/Akt, NF-κB, and Nrf2/HO-1 signaling pathways. IMP treatment obviously attenuated the production of inflammatory cytokines and inflammatory cells in bronchoalveolar lavage fluid of OVA-induced airway remodeling model. Meanwhile, it significantly inhibited inflammatory cell infiltration, goblet cell hyperplasia, collagen deposition, VEGF production, α-SMA, and ROS expression. Our study has shown that IMP could regulate the signaling pathways including MAPK, PI3K/Akt, NF-κB, and Nrf2/HO-1 to release the inflammatory responses. IMP might attenuate airway remodeling by the down-regulation of Nrf2/HO-1/ROS/PI3K/Akt, Nrf2/HO-1/ROS/MAPK, and Nrf2/HO-1/ROS/NF-κB signaling pathways.

Attenuation of allergic responses following treatment with resveratrol in anaphylactic models and IgE-mediated mast cells

Resveratrol exists widely in plant species and has a variety of anti-oxidant, anti-inflammatory, and immunomodulatory properties. However, there have been few reports regarding its anti-food allergic activity. In this study, we demonstrated that resveratrol (isolated from Abies georgei) could decrease the release of β-hexosaminidase and histamine in rat basophilic leukemia-2H3 cells. Resveratrol was not only found to suppress the development of diarrhea, up-regulate the rectal temperature of ovalbumin-allergic mice, and decrease the serum level of specific immunoglobulin E, mouse mast cell protease-1 and histamine, but also found to decrease the population of dendritic cells, B cells and mast cells of ovalbumin -allergic mice in the spleen or mesenteric lymph node. Furthermore, resveratrol inhibited the release of β-hexosaminidase and histamine in bone marrow-derived cells and alleviated mast cell-mediated passive cutaneous anaphylaxis reactions. These findings indicated that resveratrol isolated from Abies georgei might have the potential to alleviate food hypersensitivity or allergic disease.

Prophylactic Dermatologic Treatment of Afatinib-Induced Skin Toxicities in Patients with Metastatic Lung Cancer: A Pilot Study

BACKGROUND

Severe skin rash is listed among important side effects of EGFR tyrosine kinase inhibitors. Polydatin (PD), a glycosylated polyphenol, is endowed with anti-inflammatory activity in human epidermal keratinocytes.

OBJECTIVE

This study evaluated the effect of topical application of a moisturizer containing PD to prevent skin rash in patients with mutated non-small cell lung cancer (NSCLC) treated with afatinib.

MATERIALS AND METHODS

Eligible NSCLC patients with metastatic disease were treated with first-line afatinib 40 mg/die. One day before starting systemic therapy, all patients received topical administration of a 1.5% PD-based cream b.i.d. every day until the end of afatinib treatment.

RESULTS

Out of 34 treated patients, the incidence of skin rash (all grades) was 41.2% and grade 2 rash was 20.6%, and grade 3 rash was not observed in any of the patients. None of the patients discontinued therapy for toxicity. The mean duration of treatment was 6.4 months, calculated from the time treatment was started to the date treatment was stopped.

CONCLUSION

The results showed that a PD-based cream can reduce the incidence of grade ≥2 skin toxicities in patients treated with afatinib. Clinical study registration number: Prot. No. 130/CE Lazio 1 Italy.

Polydatin suppresses the development of lung inflammation and fibrosis by inhibiting activation of the NACHT domain-, leucine-rich repeat-, and pyd-containing protein 3 inflammasome and the nuclear factor-κB pathway after Mycoplasma pneumoniae infection

Mycoplasma pneumoniae (MP) can infect both the upper and lower respiratory tracts. Polydatin (PD), a traditional Chinese medicine, is known to have anti-inflammation and antifibrosis properties. However, the protective effects of PD against MP pneumonia (MPP) remain unclear. So, the aim of this study was to describe the therapeutic effects and underlying mechanisms of PD against MPP. BALB/c mice were assigned to three groups: a normal control group, MP infection group, or PD-treated MP infection group. BEAS-2B cells transfected with or without NACHT domain-, leucine-rich repeat-, and pyd-containing protein 3 (NLRP3) were used to confirm the protective mechanisms of PD. Immunohistochemical analysis, Western blot analysis, enzyme-linked immunosorbent assay, and flow cytometry were used in this study. The results showed that PD treatment suppressed MP-induced lung injury in mice by suppressing the expression of inflammatory factors and inhibiting the development of pulmonary fibrosis. Meanwhile, PD treatment inhibited activation of the NLRP3 inflammasome and nuclear factor κB (NF-κB) pathway. Overexpression of NLRP3 reversed the protective effect of PD against MP-induced injury of BEAS-2B cells. Taken together, these results indicate that PD treatment suppressed the inflammatory response and the development of pulmonary fibrosis by inhibiting the NLRP3 inflammasome and NF-κB pathway after MP infection.

New treatments and therapeutic targets for IBS and other functional bowel disorders

Functional bowel disorders (FBDs) are a spectrum of disorders characterized by combinations of symptoms attributable to the lower gastrointestinal tract. Most current first-line therapies for IBS and other FBDs target the predominant symptom and mainly affect one symptom in the symptom complex. Additional broadly effective treatment alternatives targeting the entire symptom complex are needed. New drugs for FBDs (such as lubiprostone, linaclotide, plecanatide, prucalopride, eluxadoline and rifaximin) target key mechanisms in the pathophysiology of these disorders and improve both the abnormal bowel habit and other key symptoms, such as abdominal pain and bloating. The current development of new treatment alternatives is focusing on different aspects of the complex pathophysiology of IBS and other FBDs: gut microenvironment (via diet and modulation of gut microbiota), enterohepatic circulation of bile acids, gastrointestinal secretion, motility and sensation, gut-brain interactions, gut barrier function and the immune system within the gastrointestinal tract. Studies also suggest that personalized treatment of IBS and other FBDs is possible using various diagnostic markers.

Investigation of the interaction of allergens of Glycine max with IgE-antibody for designing of peptidomimetics based anti-allergen

Allergen induced IgE dependent type I hypersensitivity is the main cause of the allergy, which would be a burden on medical setup in coming years. Allergens of Glycine max have been isolated, and their disease relationships are documented. Therefore, it becomes important to investigate the interaction of different allergens of Glycine max with IgE and also screen suitable therapeutics to prevent this interaction. The amino acid sequences of all allergens of Glycine max and their isoallergens have been taken, and 3D structure of allergens (Gly m 3, Gly m 4, Gly m 5, Gly m 6 and Gly m 8) and their isoallergens were generated using Modeller v9.17. The modeled structures were further validated using PSVS, ProSA, RAMPAGE, and PDBsum. HL domain of Fab region of human IgE (PDBID: 2R56) was generated using UCSFchimera. The HL domain was minimized by Schrodinger software using the OPLS_2005 force field. SiteMap identified epitope binding site of the minimized domain. All the predicted epitopes of different allergens were docked to the binding site of HL domain using the Patchdock server. We have also designed a peptidomimetics based inhibitor targeted at interaction interface of Gly m8 and IgE, using in-silico virtual screening, molecular mechanics, and molecular dynamics simulation studies. These studies identified BDE32166344 ((N-(1-{[1-(1-aminocyclopentanecarbonyl)-3-hydroxypyrrolidin-3-yl]methyl}piperidin-4-yl)acetamide) as a peptidomimetics based lead with binding energy of -72.77 kcal/mol. Therefore, the present study investigates the interaction between different Gly m allergens and IgE antibody and identifies peptidomimetics based lead that might be developed as a suitable therapeutics against allergy caused by allergen of Glycine max.

Patient-Specific iPSC-Based Models of Huntington's Disease as a Tool to Study Store-Operated Calcium Entry Drug Targeting

Neurodegenerative pathologies are among the most serious and socially significant problems of modern medicine, along with cardiovascular and oncological diseases. Several attempts have been made to prevent neuronal death using novel drugs targeted to the cell calcium signaling machinery, but the lack of adequate models for screening markedly impairs the development of relevant drugs. A potential breakthrough in this field is offered by the models of hereditary neurodegenerative pathologies based on endogenous expression of mutant proteins in neurons differentiated from patient-specific induced pluripotent stem cells (iPSCs). Here, we study specific features of store-operated calcium entry (SOCE) using an iPSCs-based model of Huntington's disease (HD) and analyze the pharmacological effects of a specific drug targeted to the calcium channels. We show that SOCE in gamma aminobutyric acid-ergic striatal medium spiny neurons (GABA MSNs) was mediated by currents through at least two different channel groups, ICRAC and ISOC. Both of these groups were upregulated in HD neurons compared with the wild-type neurons. Thapsigargin-induced intracellular calcium store depletion in GABA MSNs resulted in predominant activation of either ICRAC or ISOC. The potential anti-HD drug EVP4593, which was previously shown to have neuroprotective activity in different HD models, affected both ICRAC and ISOC.

Advancements in drug development for diarrhea-predominant irritable bowel syndrome

INTRODUCTION

Diarrhea-predominant irritable bowel syndrome (IBS-D) is a common disorder characterized by a complex pathophysiology hampering optimal targeted drug development. Recent advances in our understanding of key underlying mechanisms prompted novel therapeutics including novel pharmacological approaches.

AREAS COVERED

This review summarizes the latest advancements in the pipeline of IBS-D drugs focusing on new pharmacological targets, efficacy and safety of medicinal products considering the recent harmonization of regulatory requirements by the FDA and the EMA.

EXPERT OPINION

The new 5-HT₃ receptor antagonist ramosetron appears a promising therapeutic approach devoid of significant adverse events, although it is presently unavailable in Western countries, most likely because of the precautionary approach taken by regulatory agencies with this drug class. New pharmacological concepts on full agonists/antagonists, mixed-receptor activity and novel drug targets may streamline the present drug pipeline along with the adherence on new regulatory guidelines on outcome measures. Eluxadoline can be taken as an example of this paradigm shift. It has now been granted marketing authorization for IBS-D on both sides of the Atlantic, but it is still considered as a second-line agent by the NICE. There is still much work to be done to fully cover clinical needs of patients with IBS-D.

Polydatin inhibits mast cell-mediated allergic inflammation by targeting PI3K/Akt, MAPK, NF-κB and Nrf2/HO-1 pathways

Polydatin(PD) shows anti-allergic inflammatory effect, and this study investigated its underlying mechanisms in in vitro and in vivo models. IgE-mediated passive cutaneous anaphylaxis (PCA) and passive systemic anaphylaxis (PSA) models were used to confirm PD effect in vivo. Various signaling pathway proteins in mast cell were examined. RT-PCR, ELISA and western blotting were applied when appropriate. Activity of Lyn and Fyn kinases in vitro was measured using the Kinase Enzyme System. PD dose-dependently reduced the pigmentation of Evans blue in the PCA model and decreased the concentration of serum histamine in PSA model, and attenuated the degranulation of mast cells without generating cytotoxicity. PD decreased pro-inflammatory cytokine expression (TNF-α, IL-4, IL-1β, and IL-8). PD directly inhibited activity of Lyn and Syk kinases and down-regulated downstream signaling pathway including MAPK, PI3K/AKT and NF-kB. In addition, PD also targets Nrf2/HO-1 pathway to inhibit mast cell-derived allergic inflammatory reactions. In conclusion, the study demonstrates that PD is a possible therapeutic candidate for allergic inflammatory diseases. It directly inhibited activity of Lyn and Syk kinases and down-regulates the signaling pathway of MAPK, PI3K/AKT and NF-κB, and up-regulates the signaling pathway of Nrf2/HO-1 to inhibit the degranulation of mast cells.

Randomised clinical trial: the analgesic properties of dietary supplementation with palmitoylethanolamide and polydatin in irritable bowel syndrome

BACKGROUND

Intestinal immune activation is involved in irritable bowel syndrome (IBS) pathophysiology. While most dietary approaches in IBS involve food avoidance, there are fewer indications on food supplementation. Palmithoylethanolamide, structurally related to the endocannabinoid anandamide, and polydatin are dietary compounds which act synergistically to reduce mast cell activation.

AIM

To assess the effect on mast cell count and the efficacy of palmithoylethanolamide/polydatin in patients with IBS.

METHODS

We conducted a pilot, 12-week, randomised, double-blind, placebo-controlled, multicentre study assessing the effect of palmithoylethanolamide/polydatin 200 mg/20 mg or placebo b.d. on low-grade immune activation, endocannabinoid system and symptoms in IBS patients. Biopsy samples, obtained at screening visit and at the end of the study, were analysed by immunohistochemistry, enzyme-linked immunoassay, liquid chromatography and Western blot.

RESULTS

A total of 54 patients with IBS and 12 healthy controls were enrolled from five European centres. Compared with controls, IBS patients showed higher mucosal mast cell counts (3.2 ± 1.3 vs. 5.3 ± 2.7%, P = 0.013), reduced fatty acid amide oleoylethanolamide (12.7 ± 9.8 vs. 45.8 ± 55.6 pmol/mg, P = 0.002) and increased expression of cannabinoid receptor 2 (0.7 ± 0.1 vs. 1.0 ± 0.8, P = 0.012). The treatment did not significantly modify IBS biological profile, including mast cell count. Compared with placebo, palmithoylethanolamide/polydatin markedly improved abdominal pain severity (P < 0.05).

CONCLUSIONS

The marked effect of the dietary supplement palmithoylethanolamide/polydatin on abdominal pain in patients with IBS suggests that this is a promising natural approach for pain management in this condition. Further studies are now required to elucidate the mechanism of action of palmithoylethanolamide/polydatin in IBS. ClinicalTrials.gov number, NCT01370720.

Regulation of PCSK9 by nutraceuticals

PCSK9 (proprotein convertase subtilisin kexin type 9) is a liver secretory enzyme that regulates plasma low-density lipoprotein (LDL) cholesterol (LDL-C) levels through modulation of LDL receptor (LDLR) density on the surface of hepatocytes. Inhibition of PCSK9 using monoclonal antibodies can efficiently lower plasma LDL-C, non-high-density lipoprotein cholesterol and lipoprotein (a). PCSK9 inhibition is also an effective adjunct to statin therapy; however, the cost-effectiveness of currently available PCSK9 inhibitors is under question. Nutraceuticals offer a safe and cost-effective option for PCSK9 inhibition. Several nutraceuticals have been reported to modulate PCSK9 levels and exert LDL-lowering activity. Mechanistically, those nutraceuticals that inhibit PCSK9 through a SREBP (sterol-responsive element binding protein)-independent pathway can be more effective in lowering plasma LDL-C levels compared with those inhibiting PCSK9 through the SREBP pathway. The present review aims to collect available data on the nutraceuticals with PCSK9-inhibitory effect and the underlying mechanisms.

trans-Polydatin protects the mouse heart against ischemia/reperfusion injury via inhibition of the renin–angiotensin system (RAS) and Rho kinase (ROCK) activity

Background: Recent studies highlighted the protective benefits of a Chinese herb extract frompolygonum cuspidatum,trans-polydatin, on cardiac disease.

Polydatin ameliorates lipid and glucose metabolism in type 2 diabetes mellitus by downregulating proprotein convertase subtilisin/kexin type 9 (PCSK9)

BACKGROUND

Abnormalities in lipid and glucose metabolism are constantly observed in type 2 diabetes. However, these abnormalities can be ameliorated by polydatin. Considering the important role of proprotein convertase subtilisin/kexin type 9 (PCSK9) in metabolic diseases, we explore the possible mechanism of polydatin on lipid and glucose metabolism through its effects on PCSK9.

METHODS

An insulin-resistant HepG2 cell model induced by palmitic acid (PA) and a db/db mice model were used to clarify the role of polydatin on lipid and glucose metabolism.

RESULTS

In insulin-resistant HepG2 cells, polydatin upregulated the protein levels of LDLR and GCK but repressed PCSK9 protein expression, besides, polydatin also inhibited the combination between PCSK9 and LDLR. Knockdown and overexpression experiments indicated that polydatin regulated LDLR and GCK expressions through PCSK9. In the db/db mice model, we found that polydatin markedly enhanced GCK and LDLR protein levels, and inhibited PCSK9 expression in the liver. Molecular docking assay was further performed to analyze the possible binding mode between polydatin and the PCSK9 crystal structure (PDB code: 2p4e), which indicated that steady hydrogen bonds formed between polydatin and PCSK9.

CONCLUSIONS

Our study indicates that polydatin ameliorates lipid and glucose metabolism in type 2 diabetes mellitus by downregulating PCSK9.

Lentiviral shRNA against KCa3.1 inhibits allergic response in allergic rhinitis and suppresses mast cell activity via PI3K/AKT signaling pathway

Calcium-activated potassium ion channel-3.1 (KCa3.1) plays a pivotal role in the potassium-calcium exchange involved in atopy. This study aimed to explore the impact of lentiviral-mediated shRNA silencing KCa3.1 on allergic response in a murine allergic rhinitis (AR) model. The BALB/c mice were divided into four groups: untreated AR group, negative control AR group, lentiviral KCa3.1-shRNA treated AR group and normal control group. Concentrations of ovalbumin (OVA)-specific IgE, histamine and leukotrienes C4 (LTC4) in serum, and IL-4, IL-9 and IL-17 in nasal lavage fluid (NLF) were analyzed. Goblet cells and mast cells were counted. KCa3.1 positive cells were counted after immunolabelling by immunofluorescence method. KCa3.1, Mucin 5AC (MUC5AC), and tryptase mRNA levels were determined using real-time polymerase chain reaction. Furthermore, P815 cell line was used to explore the role and mechanism of lentiviral KCa3.1-shRNA on mast cells. The results showed that LV-KCa3.1-shRNA intervention effectively attenuated allergic responses in LV-KCa3.1-shRNA treated mice. LV-KCa3.1-shRNA intervention effectively suppressed KCa3.1 levels and phosphorylation of AKT in P815 cells, leading to the downregulation of tryptase, IL-6 and IL-8 levels. LV-KCa3.1-shRNA intervention effectively attenuated the allergic responses in AR and suppressed mast cell activity by inhibiting PI3K/AKT signaling pathway.