Selexipag Dosing Strategies for Pediatric Patients with Pulmonary Arterial Hypertension.

This retrospective chart review of patients less than 18 years old with pulmonary arterial hypertension (PAH) receiving selexipag was conducted to describe selexipag dosing practices, impact on concomitant PAH therapies, and the safety and efficacy of selexipag. Twenty-seven patients aged 1-17 years started a median dose of oral selexipag 100 µg twice daily. Therapy was increased by a median of 100 µg twice daily every 6 days to a maximally tolerated median dose of 800 µg twice daily. All 24 patients on another prostacyclin derivative were able to discontinue therapy at their maximum tolerated selexipag dose; other concomitant PAH therapies did not change. Changes in echocardiogram data and 6-MWT results were variable. No patients discontinued selexipag; four patients received decreased doses due to flushing (n = 1), drug interactions (n = 2), or increased frequency of nose bleeds (n = 1).

Efficacy and safety of non-prostanoid prostacyclin receptor agonist for pulmonary hypertension: A meta-analysis.

BACKGROUND: Oral non-prostanoid prostacyclin receptor agonists therapies have been recommended for pulmonary arterial hypertension in many countries. OBJECTIVE: We aimed to evaluate the specific impact of non-prostanoid prostacyclin receptor agonists on pulmonary hypertension and to explore the influence of study characteristics on results. METHODS: PubMed, Embase, and ClinicalTrials.gov were systematically searched from inception to July 12, 2022. Randomized controlled trials comparing non-prostanoid prostacyclin receptor agonists administration with placebo for treating pulmonary hypertension were included. Two researchers independently selected eligible studies, assessed the bias risk and extracted related data. RevMan5.1 was used for performing the statistical analysis and the assessment of bias risk of the enrolled studies. PROSPERO registered number CRD42022304172. RESULTS: Seven trials involving 1727 patients were included. Pooled analyses indicated non-prostanoid prostacyclin receptor agonists significantly reduced clinical worsening events (risk ratio [RR], 0.63; 95% confidence interval [CI], 0.54 to 0.74), increased 6-min walk distance (mean difference [MD], 10 m; 95% CI, 3-17 m), decreased pulmonary vascular resistance (MD, -121 dyn s/cm5; 95% CI, -172 to -69 dyn s/cm5) and increased cardiac index (MD, 0.38 L/min/m2; 95% CI, 0.26-0.50 L/min/m2) compared with the control. No significant differences in all-cause mortality (RR, 0.86; 95% CI, 0.26 to 2.78), NYHA/WHO functional class (RR, 1.16; 95% CI, 0.61 to 2.18), mean pulmonary artery pressure (MD, -0.88 mmHg; 95% CI, -2.20 to 0.44 mmHg), right atrial pressure (MD, 0.66 mmHg; 95% CI, -0.59 to 1.90 mmHg) and total adverse events (RR, 1.05; 95% CI, 0.99 to 1.10) were found between non-prostanoid prostacyclin receptor agonists group and control group. CONCLUSION: Non-prostanoid prostacyclin receptor agonists treatment exerted benefits on clinical worsening, pulmonary vascular resistance, and cardiac index in pulmonary hypertension patients, without increasing the incidence of total adverse events.

Association of N-Terminal Pro Brain Natriuretic Peptide and Long-Term Outcome in Patients With Pulmonary Arterial Hypertension.

BACKGROUND: NT-proBNP (N-terminal pro brain natriuretic peptide) levels are included in the multiparametric risk assessment approach for pulmonary arterial hypertension (PAH) outlined in PAH guidelines. However, data supporting the use of NT-proBNP risk thresholds in assessing prognosis in PAH are limited. The GRIPHON trial (Prostacyclin [PGI2] Receptor Agonist In Pulmonary Arterial Hypertension) provides an opportunity to assess the prognostic value of NT-proBNP thresholds in a controlled clinical trial and to evaluate the response to selexipag according to these thresholds. METHODS: The event-driven GRIPHON trial randomly assigned patients to selexipag or placebo. NT-proBNP was measured at regular intervals in GRIPHON. Here, patients were categorized post hoc into low, medium, and high NT-proBNP subgroups according to 2 independent sets of thresholds: (1) baseline tertiles: <271 ng/L; 271 to 1165 ng/L; >1165 ng/L; and (2) 2015 European Society of Cardiology/European Respiratory Society guidelines cutoffs: <300 ng/L; 300 to 1400 ng/L; >1400 ng/L. Hazard ratios (selexipag versus placebo) with 95% CIs were calculated for the primary end point (composite morbidity/mortality events) by NT-proBNP category at baseline using Cox proportional-hazards models, and at any time during the exposure period using a time-dependent Cox model. RESULTS: With both thresholds, baseline and follow-up NT-proBNP categories were highly prognostic for future morbidity/mortality events during the study ( P<0.0001). In the time-dependent analysis, the risk of experiencing a morbidity/mortality event was 92% and 83% lower in selexipag-treated patients with a low and medium NT-proBNP level, and 90% and 56% lower in placebo-treated patients with a low and medium NT-proBNP level, in comparison with patients with a high NT-proBNP level. Selexipag reduced the risk of morbidity/mortality events across all 3 NT-proBNP categories in both the baseline and time-dependent analyses, with a more pronounced treatment benefit of selexipag seen in the medium and low NT-proBNP subgroups (interaction P values 0.20 and 0.007 in the baseline and time-dependent analyses). CONCLUSIONS: These analyses further establish the prognostic relevance of NT-proBNP levels in PAH and provide first evidence for the association of NT-proBNP level and treatment response. Using 2 similar sets of thresholds, these analyses support the relevance of the low, medium, and high NT-proBNP categories as part of the multiparametric risk assessment approach outlined in the European Society of Cardiology/European Respiratory Society guidelines for the management of PAH patients. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov . Unique identifier: NCT01106014.

Selexipag for Chronic Thromboembolic Pulmonary Hypertension in Japanese Patients　- A Double-Blind, Randomized, Placebo-Controlled, Multicenter Phase II Study.

BACKGROUND: Selexipag is an oral prostacyclin receptor (IP receptor) agonist with a non-prostanoid structure. This study examined its efficacy and safety in Japanese patients with non-operated or persistent/recurrent chronic thromboembolic pulmonary hypertension (CTEPH).Methods and Results:This Phase II study was a randomized, double-blind, placebo-controlled parallel-group comparison. The primary endpoint was a change in pulmonary vascular resistance (PVR) from baseline to week 17. The main analysis involved a per-protocol set group of 28 subjects. The change in PVR (mean±SD) after 17 weeks of treatment in the selexipag group was -104±191 dyn·s/cm5, whereas that in the placebo group was 26±180 dyn·s/cm5. Thus, the treatment effect after 17 weeks of selexipag treatment was calculated as -130±189 dyn·s/cm5(P=0.1553). Although the primary endpoint was not met, for the group not concomitantly using a pulmonary vasodilator the PVR in the selexipag group was significantly decreased compared with placebo group (P=0.0364). The selexipag group also showed improvement in total pulmonary resistance and cardiac index. CONCLUSIONS: Selexipag treatment improved pulmonary hemodynamics in Japanese patients with CTEPH, but PVR did not show a significant difference between the selexipag and placebo groups. (Trial registration: JAPIC Clinical Trials Information [JapicCTI-111667]).

Mannitol triggers mast cell-dependent contractions of human small bronchi and prostacyclin bronchoprotection.

BACKGROUND: Clinical research supports that exercise-induced bronchoconstriction (EIB) is caused by hyperosmolar triggering of mast cells. The reaction can be mimicked by inhalation of mannitol, but it has paradoxically previously not been possible to replicate this mode of action of mannitol in isolated airways. OBJECTIVE: We sought to establish an ex vivo model of EIB in human small bronchi. METHODS: Small bronchi (inner diameter, 0.5-2 mm) from macroscopically healthy human lung tissue were obtained from 48 patients and mounted in organ baths. Contractions and mediator release were analyzed after challenge with hyperosmolar mannitol (850 mOsm). RESULTS: Ten minutes of exposure to mannitol caused a small initial contraction (12% ± 1% of maximum) that was followed by a second and much larger contraction (maximum effect [Emax], 47% ± 5%) when mannitol was washed out. The mast cell stabilizer cromolyn reduced the second contraction (Emax, 27% ± 3%). Furthermore, this main contraction was abolished by the combination of antagonists of histamine and cysteinyl leukotrienes in the presence of indomethacin. Mannitol increased the release of the mast cell mediators histamine (9.0-fold), cysteinyl leukotrienes (4.5-fold), and prostaglandin (PG) D2 (5.4-fold), as well as PGE2 (6.3-fold) and the prostacyclin metabolite 6-keto PGF1α (5.7-fold). In contrast, indomethacin alone enhanced the bronchoconstriction (Emax, 68% ± 6%). Likewise, receptor antagonists for PGE2 (EP2 and EP4) and prostacyclin (IP) also enhanced the mannitol-induced bronchoconstriction (Emax, 67% ± 5%, 66% ± 4%, and 68% ± 3%, respectively). In bronchi precontracted by carbachol, the IP receptor agonist cicaprost induced profound relaxation. CONCLUSION: This new protocol established an in vitro model for studies of EIB in isolated human bronchi. The IP receptor might be a new target for asthma treatment.

The Antifibrotic Activity of Prostacyclin Receptor Agonism Is Mediated through Inhibition of YAP/TAZ.

Idiopathic pulmonary fibrosis is a life-threatening progressive disease characterized by loss of alveolar epithelial cells, inflammation, and aberrant fibroblast activation. The two currently approved therapies do not halt or reverse tissue remodeling, and therefore novel disease-modifying mechanisms are needed. Our results describe YAP/TAZ inhibition through prostacyclin (IP) receptor activation as a novel mechanism that suppresses profibrotic (myo)fibroblast activity. We investigated the antifibrotic properties of the selective IP receptor agonist ACT-333679 using primary human lung fibroblasts. ACT-333679 prevented transforming growth factor ß1-induced fibroblast-to-myofibroblast transition, proliferation, extracellular matrix synthesis, and IL-6 and PAI-1 secretion, and exerted relaxant effects in cell contraction assays. ACT-333679 treatment also reverted an established myofibroblast phenotype. Unbiased analysis of ACT-333679-induced whole-genome expression changes in transforming growth factor ß1-treated fibroblasts identified significant attenuation of genes regulated by YAP/TAZ, two transcriptional cofactors that are essential for fibrosis. We then demonstrated that ACT-333679, via elevation of cAMP, caused YAP/TAZ nuclear exclusion and subsequent suppression of YAP/TAZ-dependent profibrotic gene transcription. In summary, we offer a rationale for further exploring the potential of IP receptor agonists for the treatment of idiopathic pulmonary fibrosis.

Cross-species comparison of the metabolism and excretion of selexipag.

1. The metabolism of the prostacyclin receptor agonist selexipag (NS-304; ACT-293987) and its active metabolite MRE-269 (ACT-333679) has been investigated in liver microsomes and hepatocytes of rats, dogs, and monkeys. MRE-269 formation is the main pathway of selexipag metabolism, irrespective of species. Some interspecies differences were evident for both compounds in terms of both metabolic turnover and metabolic profiles. The metabolism of MRE-269 was slower than that of selexipag in all three species. 2. The metabolism of selexipag was also studied in bile-duct-cannulated rats and dogs after a single oral and intravenous dose of [14C]selexipag. MRE-269 acyl glucuronide was found in both rat and dog bile. Internal acyl migration reactions of MRE-269 glucuronide were identified in an experiment with the synthetic standard MRE-6001. 3. MRE-269 was the major component in the faeces of rats and dogs. In ex vivo study using rat and dog faeces, selexipag hydrolysis to MRE-269 by the intestinal microflora is considered to be a contributory factor in rats and dogs. 4. A taurine conjugate of MRE-269 was identified in rat bile sample. Overall, selexipag was eliminated via multiple routes in animals, including hydrolysis, oxidative metabolism, conjugation, intestinal deconjugation, and gut flora metabolism.

Pharmacokinetics of the selective prostacyclin receptor agonist selexipag in rats, dogs and monkeys.

1. This study examined the pharmacokinetics, distribution, metabolism and excretion of the selective prostacyclin receptor agonist selexipag (NS-304; ACT-293987) and its active metabolite MRE-269 (ACT-33679). The compounds were investigated following oral and/or intravenous administration to intact rats, dogs and monkeys, and bile-duct-cannulated rats and dogs. 2. After oral administration of [14C]selexipag, selexipag was well absorbed in rats and dogs with total recoveries of over 90% of the dose, mainly in the faeces. Biliary excretion was the major elimination pathway for [14C]MRE-269 as well as [14C]selexipag, while renal elimination was of little importance. [14C]Selexipag-related radioactivity was secreted into the milk in lactating rats. 3. Plasma was analysed for total radioactivity, selexipag and MRE-269 in rats and monkeys. Selexipag was negligible in rat plasma due to extensive metabolism, and MRE-269 was present in rat and monkey plasma. A species difference was clearly evident when selexipag was incubated in rat, dog and monkey plasma. 4. Total radioactivity was rapidly distributed to tissues. The highest concentrations were found in the bile duct and liver without significant accumulation or persistence, while there was limited melanin-associated binding, penetration of the blood-brain barrier and placental transfer of drug-related materials.

The metabolism and drug-drug interaction potential of the selective prostacyclin receptor agonist selexipag.

1. The metabolism of selexipag has been studied in vivo in man and the main excreted metabolites were identified. Also, metabolites circulating in human plasma have been structurally identified and quantified. 2. The main metabolic pathway of selexipag in man is the formation of the active metabolite ACT-333679. Other metabolic pathways include oxidation and dealkylation reactions. All primary metabolites undergo subsequent hydrolysis of the sulphonamide moiety to their corresponding acids. ACT-333679 undergoes conjugation with glucuronic acid and aromatic hydroxylation to P10, the main metabolite detected in human faeces. 3. The formation of the active metabolite ACT-333679 is catalysed by carboxylesterases, while the oxidation and dealkylation reactions are metabolized by CYP2C8 and CYP3A4. CYP2C8 is the only P450 isoform catalysing the aromatic hydroxylation to P10. CYP2C8 together with CYP3A4 are also involved in the formation of several minor ACT-333679 metabolites. UGT1A3 and UGT2B7 catalyse the glucuronidation of ACT-333679. 4. The potential of selexipag to inhibit or induce cytochrome P450 enzymes or drug transport proteins was studied in vitro. Selexipag is an inhibitor of CYP2C8 and CYP2C9 and induces CYP3A4 and CYP2C9 in vitro. Also, selexipag inhibits the transporters OATP1B1, OATP1B3, OAT1, OAT3, and BCRP. However, due to its low dose and relatively low unbound exposure, selexipag has a low potential for causing drug-drug interactions.

Regulated expression of the prostacyclin receptor (IP) gene by androgens within the vasculature: Combined role for androgens and serum cholesterol.

The prostanoid prostacyclin plays a key cardioprotective role within the vasculature. There is increasing evidence that androgens may also confer cardioprotection but through unknown mechanisms. This study investigated whether the androgen dihydrotestosterone (DHT) may regulate expression of the prostacyclin/I prostanoid receptor or, in short, the IP in platelet-progenitor megakaryoblastic and vascular endothelial cells. DHT significantly increased IP mRNA and protein expression, IP-induced cAMP generation and promoter (PrmIP)-directed gene expression in all cell types examined. The androgen-responsive region was localised to a cis-acting androgen response element (ARE), which lies in close proximity to a functional sterol response element (SRE) within the core promoter. In normal serum conditions, DHT increased IP expression through classic androgen receptor (AR) binding to the functional ARE within the PrmIP. However, under conditions of low-cholesterol, DHT led to further increases in IP expression through an indirect mechanism involving AR-dependent upregulation of SCAP expression and enhanced SREBP1 processing & binding to the SRE within the PrmIP. Chromatin immunoprecipitation assays confirmed DHT-induced AR binding to the ARE in vivo in cells cultured in normal serum while, in conditions of low cholesterol, DHT led to increased AR and SREBP1 binding to the functional ARE and SRE cis-acting elements, respectively, within the core PrmIP resulting in further increases in IP expression. Collectively, these data establish that the human IP gene is under the transcriptional regulation of DHT, where this regulation is further influenced by serum-cholesterol levels. This may explain, in part, some of the protective actions of androgens within the vasculature.

Synthesis of both enantiomers of 1,2,3,4-tetrahydroisoquinoline derivative IPPAM-1 and enantio-dependency of its positive allosteric modulation of prostacyclin receptor.

We present a practical synthesis of both enantiomers of 1,2,3,4-tetrahydroisoquinoline derivative IPPAM-1 (1), which is a positive allosteric modulator (PAM) of prostacyclin receptor (IP) and a candidate for treatment of pulmonary arterial hypertension without the side effects caused by IP agonists. Assay of cAMP production by CHO-K1 cells stably expressing human IP clearly demonstrated that the IPPAM activity resides exclusively on the R-form of 1.

Efficacy and Safety of an Orally Administered Selective Prostacyclin Receptor Agonist, Selexipag, in Japanese Patients With Pulmonary Arterial Hypertension.

BACKGROUND: Selexipag is an orally available prostacyclin receptor (IP receptor) agonist with a non-prostanoid structure. In this open-label Phase II trial, the efficacy and safety of selexipag in Japanese patients with pulmonary arterial hypertension (PAH) is examined.Methods and Results:Selexipag was administered at 200 µg twice daily and titrated up to 1,600 µg by increments of 200 µg in 37 subjects to reach the individual maximum tolerated dose. At 16 weeks, in 33 patients comprising the per-protocol set, the pulmonary vascular resistance (PVR; primary endpoint) decreased from 683.2±237.3 to 560.3±238.7 dyn·s/cm5(P<0.0001). For the secondary endpoint, the 6-min walk distance (6MWD) increased from 445.0±102.2 to 459.1±112.8 m (P=0.0324); World Health Organization functional class improved in 4 patients (12.1%), and was maintained in 29 patients (87.9%). A decrease in PVR was also shown in patients treated with selexipag, on top of a phosphodiesterase inhibitor and endothelin receptor antagonist. Most of the commonly reported adverse events were consistent with those reported for other PGI2formulations. Thirty-four patients attained the individual maximum tolerated dose (maintenance dose). CONCLUSIONS: The efficacy and tolerability of selexipag in Japanese PAH patients was confirmed by improvement in pulmonary hemodynamics, exercise capacity, symptoms. Selexipag is an efficacious treatment option for Japanese PAH patients. (Trial registration: JAPIC Clinical Trials Information [JapicCTI-111532].).

Selexipag, an Oral Prostacyclin-Receptor Agonist for Pulmonary Arterial Hypertension.

OBJECTIVE: To evaluate the data supporting the approval of selexipag and discuss its potential place in therapy for managing pulmonary arterial hypertension (PAH). DATA SOURCES: A systematic review of the literature for all relevant articles was performed through January 16, 2017, using MEDLINE and SCOPUS. A manual search of references from reports of clinical trials, review articles, and recent conference abstracts was performed to identify additional relevant studies. STUDY SELECTION AND DATA EXTRACTION: Eligible citations included in vitro or in vivo evaluations of selexipag, with no restrictions on patient population or indication. Data related to the patient populations and outcomes of interest were extracted from each citation. DATA SYNTHESIS: Single phase II and phase III trials have been published evaluating selexipag in patients with PAH. In 43 patients, the phase II trial showed that selexipag significantly reduced pulmonary vascular resistance by 30% versus placebo ( P = 0.0045) and improved 6-minute walk distance by 24 m ( P < 0.05). The larger phase III trial enrolled 1156 patients with PAH, showing that selexipag lowered the incidence of death or PAH-related complications by 40% versus placebo ( P < 0.001). Selexipag also improved 6-minute walk distance and lowered hospitalization risk. Common adverse events included headache, diarrhea, nausea, and jaw pain. CONCLUSIONS: The specific role of selexipag for managing PAH patients is unclear because of its modest efficacy, lack of mortality reduction, and cost similar to intravenous prostacyclins. Additional clinical trials exploring combination therapy as well as its role in other types of pulmonary hypertension are needed.

Absolute oral bioavailability of selexipag, a novel oral prostacyclin IP receptor agonist.

PURPOSE: The aim of this single-center, open-label study was to assess the absolute bioavailability of an oral (tablet) versus intravenous (i.v.) formulation of selexipag in healthy subjects. METHODS: A pilot phase in three healthy male subjects, which preceded the main study, consisted of a single 20-minute i.v. infusion of 50 µg selexipag. Its objectives were to ensure the safety of the i.v. formulation and to select the i.v. dose for the main study. The main study had a randomized, two-way crossover design in 16 healthy male subjects. Subjects received a single oral dose of 400 µg selexipag and a single 80-minute i.v. infusion of 200 µg selexipag. RESULTS: Three subjects in the pilot and 15 in the main phase completed the study as planned, whereas one subject of the main study withdrew the consent. A geometric mean total body clearance (95% confidence interval (CI)) of 17.9 L/h (15.0-21.5) and a volume of distribution of 11.7 L (10.6-13.0) were determined. The absolute oral bioavailability of selexipag (90% CI) was 49.4% (42.6-57.2). Selexipag was well-tolerated; no adverse event (AE) occurred during the pilot phase, and the main observed AEs were headache, nausea, and vomiting. CONCLUSION: A single i.v. administration of selexipag in healthy subjects was safe and well-tolerated. The bioavailability of selexipag after oral administration is approximately 50%.

[Update pulmonary arterial hypertension : Definitions, diagnosis, therapy]. / Update pulmonalarterielle Hypertonie : Definitionen, Diagnose, Therapie.

The term pulmonary arterial hypertension comprises a group of pulmonary vascular diseases of different etiologies that are characterized by similar precapillary vascular remodeling processes and result in exertional dyspnea and right heart insufficiency. The specific pharmacological treatment approach considers the risk of mortality and phenotypical properties and includes treatment with phosphodiesterase type 5 inhibitors, endothelin receptor antagonists and prostanoids, as well as with more novel substances, such as a soluble guanylyl cyclase stimulator and an oral prostacyclin receptor agonist. The prognosis of the disease is mainly determined by the right heart insufficiency for which there is currently no specific pharmacological treatment. Lung transplantation may be offered as a last option. This review provides an overview of the current European guidelines from 2015 and the recommendations of the Cologne Consensus Conference for pulmonary hypertension from 2016.

Prostacyclin receptor expression on platelets of humans with type 2 diabetes is inversely correlated with hemoglobin A1c levels.

Inappropriate platelet aggregation can result in thrombosis and tissue ischemia. When compared to healthy human platelets, those of humans with type 2 diabetes (DM2) exhibit increased aggregation when stimulated. Activation of the platelet prostacyclin receptor (IPR) results in cAMP accumulation and inhibition of platelet aggregation. We hypothesized that DM2 platelets express decreased IPR when compared to platelets of healthy humans, resulting in decreased IPR agonist-induced cAMP accumulation. We measured IPR expression with radioligand binding of [(3)H]-iloprost, a stable prostacyclin analog, and with Western blotting of the IPR protein. Iloprost-stimulated platelet cAMP levels were used to identify the functional response to IPR activation. IPR binding, expression of the IPR protein and the levels of cAMP in platelets incubated with iloprost were significantly decreased in DM2 platelets when compared to platelets of healthy humans. IPR expression decreased in platelets as glycemic control of the subjects worsened, as indicated by increased hemoglobin A1c levels. Taken together, these findings suggest that reduced IPR expression in DM2 platelets may contribute to platelet hyperactivity in humans with type 2 diabetes.

Prostacyclin receptors: Transcriptional regulation and novel signalling mechanisms.

The prostanoid Prostacyclin plays diverse physiologic roles within the vasculature and other systems, and is widely implicated in several cardiovascular, pulmonary and renal diseases. Despite this, knowledge of the factors regulating expression of the I prostanoid receptor (the IP) remained largely unknown. This review details recent advances in understanding the key transcriptional regulators determining expression of the PTGIR gene in the human vasculature and the identification of novel interacting partners of the IP that impact on its function therein. Included in this are the trans-acting factors that regulate expression of the PTGIR under basal- and regulated-conditions, particularly those determining its up-regulation in response to cellular differentiation, estrogen and low serum-cholesterol. Moreover, the functional implications of the interactions between the IP with PDZK1, a multi PDZ-domain containing protein essential for reverse-cholesterol transport and endothelialization, and the IP with IKEPP, the intestinal and kidney enriched PDZ protein, for the role of the prostacyclin-IP axis within the vasculature are reviewed.

[Expression of prostacyclin receptor in chronic rhinosinusitis and its relationship with type 2 inflammation].

Objective:The purpose of this study is to explore the expression of prostacyclin receptor（IP） in patients with chronic rhinosinusitis（CRS） and its possible association with type 2 inflammation. Methods:HE staining was used to observe the morphological changes of nasal mucosa, qRT-PCR was used to detect the expression of IP in polyps and nasal mucosa, and IHC was used to detect the expression of IP, IL-4, IL-5 and IL-13 in polyps and nasal mucosa. Results:Compared with the control group, the nasal mucosa of patients with various types of CRS was obviously thickened, accompanied by inflammatory cell infiltration and gland hyperplasia. The statistical results of IHC showed that the expression levels of IL-4, IL-5 and IL-13 in CRS group were significantly higher than those in control group（P<0.05）, and the IP expression in control group was significantly higher than that in ECRS group and non-ECRS group（P<0.05）. The IP expression in ECRS group was negatively correlated with IL-4, IL-5 and IL-13. The results of qRT-PCR showed that the expression of IP mRNA in control group was significantly higher than that in ECRS group and non-ECRS group（P<0.05）. Conclusion:IL-4, IL-5 and IL-13 are highly expressed in the nasal mucosa of CRS patients, while IP is poorly expressed in the nasal mucosa of CRS patients, and IP is negatively correlated with IL-4, IL-5 and IL-13, suggesting that IP is related to the occurrence and development of type 2 inflammation and may be a potential therapeutic target for CRS patients.

Inhibition of TRPM8 function by prostacyclin receptor agonists requires coupling to Gq/11 proteins.

BACKGROUND AND PURPOSE: The TRPM8 ion channel is involved in innocuous cold sensing and has a potent anti-inflammatory action. Its activation by lower temperature or chemical agonists such as menthol and icilin induces analgesic effects, reversing hypersensitivity and reducing chronic pain. On the other hand, prostacyclin (PGI2) enhances pain and inflammation by activating the IP receptors. Due to the critical roles of TRPM8 and IP receptors in the regulation of inflammatory pain, and considering their overlapping expression pattern, we analysed the functional interaction between human TRPM8 and IP receptors. EXPERIMENTAL APPROACH: We transiently expressed human TRPM8 channels and IP receptors in HEK293T cells and carried out intracellular calcium and cAMP measurements. Additionally, we cultured neurons from the dorsal root ganglia (DRGs) of mice and determined the increase in intracellular calcium triggered by the TRPM8 agonist, icilin, in the presence of the IP receptor agonist cicaprost, the IP receptor antagonist Cay10441, and the Gq/11 inhibitor YM254890. KEY RESULTS: Activation of IP receptors by selective agonists (cicaprost, beraprost, and iloprost) inhibited TRPM8 channel function, independently of the Gs-cAMP pathway. The potent inhibition of TRPM8 channels by IP receptor agonists involved Gq/11 coupling. These effects were also observed in neurons isolated from murine DRGs. CONCLUSIONS AND IMPLICATIONS: Our results demonstrate an unusual signalling pathway of IP receptors by coupling to Gq/11 proteins to inhibit TRPM8 channel function. This pathway may contribute to a better understanding of the role of TRPM8 channels and IP receptors in regulating pain and inflammation.