u-62840 and beraprost

Prostacyclin is produced in vascular endothelial cells and acts via the IP prostacyclin receptor to cause vasodilation and inhibit smooth muscle cell proliferation and platelet aggregation. Prostacyclin production is reduced in pulmonary arterial hypertension (PAH), and drugs targeting the prostacyclin pathway are one of the pharmacotherapeutic options for PAH. Areas covered: The prostacyclin pathway and drugs that target it are discussed, including synthetic prostacyclin (epoprostenol), prostacyclin analogs (iloprost, treprostinil, beraprost) and selective prostacyclin IP receptor agonists (selexipag). An overview of the development of these therapies, from the earlier agents requiring parenteral administration, through inhaled formulations, to oral products, is provided, together with a summary of data from key clinical trials and registries. Expert commentary: Synthetic prostacyclin and prostacyclin analogs are beneficial for patients with PAH, but they tend to be underused, in part due to the difficulties associated with the administration of parenteral and inhaled formulations. Oral prostacyclin analogs have some limitations with regard to efficacy. The newest agent targeting the prostacyclin pathway, the selective prostacyclin receptor agonist selexipag, is administered orally, and has been shown to reduce a composite morbidity/mortality endpoint. Ongoing studies will help clarify how best to use it in the management of PAH.

Topics: Acetamides; Antihypertensive Agents; Epoprostenol; Humans; Hypertension, Pulmonary; Pyrazines; Receptors, Epoprostenol

Prostacyclin pathway medications have been shown to be highly efficacious in the treatment of pulmonary arterial hypertension (PAH) through multiple prospective clinical trials and more than two decades of clinical experience. The strongest support for prostacyclin use in PAH management is with parenteral administration. Numerous risks and limitations of parenteral delivery systems as well as significant patient burdens restrict widespread parenteral use. Highly effective and tolerable oral prostacyclin preparations to manage PAH have long been sought. We review the development of the oral prostacyclin agents beraprost, treprostinil, and selexipag and including current indications and limitations. Research into new approaches to the management of PAH, expanding indications for existing agents, and development of novel agents are also discussed.. Two oral prostacyclin pathway medications, oral treprostinil and selexipag, were FDA approved in December 2013 and 2015, respectively. Current guidelines recommend use of selexipag in WHO-FC II and III (class 1, level B recommendation) and oral treprostinil in WHO-FC III (class 2b, level B recommendation). The use of these medications is challenging due to complexity in dosing and their side effect profiles which limit patient tolerability and acceptance. There is a promising role for oral prostacyclin pathway medications in patients with PAH. Future investigations are underway of alternative dose regimens and transitioning from parenteral therapies in order to improve efficacy and tolerability.

Topics: Acetamides; Antihypertensive Agents; Epoprostenol; Humans; Hypertension, Pulmonary; Pyrazines

Prostacyclin analogs, such as epoprostenol, treprostinil, iloprost, and beraprost, have long been used for pulmonary arterial hypertension (PAH) treatment, yet their relative efficiency remains disputed. Eligible randomized controlled trials (RCTs) involving the 4 therapies mentioned above were retrieved from PubMed, Embase, and Cochrane (up to August 1, 2015). Odds ratios (ORs) were estimated for dichotomous data (mortality, functional class (FC) amelioration, and discontinuation); standardized mean differences (SMDs) with 95% confidence intervals (CIs) were estimated for continuous data (6-min walk distance [6-MWD]). Patients taking epoprostenol were anticipated to demonstrate more expedient 6-MWD than those taking placebo when network meta-analysis (NMA) was implemented (SMD = 52.19; 95% CI: 24.28-113.39), the trend of which was identical with that of pairwise meta-analysis (SMD = 69.28; 95% CI: 10.43-128.98). Nonetheless, the prominent advantages of treprostinil over placebo (SMD = 30.15; 95% CI: 19.29-40.01) in 6-MWD could not be replicated by NMA. Furthermore, direct and indirect (NMA) comparisons also differed in FC amelioration. For example, the superiority of epoprostenol over placebo as evident with the use of NMA (OR = 42.79; 95% CI: 10.63-301.98) could not be confirmed by pairwise meta-analysis. As suggested by indirect comparisons among 4 prostanoids, epoprostenol appears to result in remarkably favorable FC amelioration comparing to other regimens (all P < 0.05). Participants taking beraprost were more probable to withdraw in comparison with those administrated with iloprost (OR = 10.07; 95% CI: 1.47-160.65). Taking mortality, FC amelioration, discontinuation, and 6-MWD into account, epoprostenol could be recommended as an alternative treatment for patients with moderate/advanced PAH.

Topics: Antihypertensive Agents; Arterial Pressure; Epoprostenol; Humans; Hypertension, Pulmonary; Iloprost; Randomized Controlled Trials as Topic

It is well established that the endothelin, nitric oxide and prostacyclin pathways play an important role in the development of pulmonary arterial hypertension (PAH). Indeed, the therapeutic options currently available for the management of PAH all act on one of these mechanistic pathways. However, this is an exciting time for both clinicians and scientists, as increased understanding of the mechanisms involved in the pathogenesis and progression of PAH has resulted in the development of a number of novel therapeutic options. This article highlights how the introduction of new compounds such as macitentan, riociguat and selexipag, which act on the endothelin, nitric oxide and prostacyclin pathways, respectively, have the potential to further improve the prognosis for patients with PAH.

Topics: Acetamides; Animals; Antihypertensive Agents; Benzamides; Clinical Trials as Topic; Drugs, Investigational; Endothelin A Receptor Antagonists; Endothelin B Receptor Antagonists; Endothelin-1; Epoprostenol; Guanylate Cyclase; Humans; Hypertension, Pulmonary; Imatinib Mesylate; Lisuride; Nitric Oxide; Phosphodiesterase 5 Inhibitors; Piperazines; Protein Kinase Inhibitors; Pyrazines; Pyrazoles; Pyrimidines; Serotonin Antagonists; Sulfonamides

Epoprostenol and the structurally related compounds treprostinil, iloprost, and beraprost are collectively referred to as prostanoids. The discovery of epoprostenol in 1976 and unequivocal demonstration of its efficacy in 1996 dramatically altered the approach to therapy for pulmonary arterial hypertension (PAH). Development of prostanoids available through multiple routes of administration and the discovery and development of other agents acting through alternative pathways continue to expand the array of therapeutic options. The use of prostanoids in combination with other PAH drugs and for treating pulmonary hypertensive disorders outside of the PAH classification are areas of ongoing research.

Topics: Antihypertensive Agents; Chronic Disease; Epoprostenol; Heart Defects, Congenital; Humans; Hypertension, Portal; Hypertension, Pulmonary; Iloprost; Prostaglandins; Randomized Controlled Trials as Topic; Respiratory Distress Syndrome

Pulmonary arterial hypertension (PAH) is a life-threatening disease characterized by vasoconstriction and progressive remodelling of the pulmonary arterial wall leading to right ventricular failure and death. Idiopathic PAH (IPAH) and PAH associated with congenital heart defects account for the majority of paediatric patients with PAH. During the last few decades, several pharmacological approaches have been introduced, including calcium channel-blockers (CCBs), prostacyclin analogues, endothelin receptor antagonists and, most recently, phosphodiesterase inhibitors. This paper reviews the treatment options available to children with a special focus on the initial experience with bosentan. Although CCBs have been shown to increase survival in IPAH, the beneficial effect appears to be limited to a small number of patients, defined as 'responders' to the vasoreactivity testing. With the availability of prostacyclin (intravenous epoprostenol) and then prostacyclin analogues, the treatment options have increased markedly and particularly in patients who have not responded to conventional therapy. Although epoprostenol has been shown to be efficacious in PAH, the drug is not ideal owing to serious complications arising from the invasive mode of application, particularly in children. Phosphodiesterase-5 inhibitors have also shown beneficial effects. Targeting the endothelin (ET) system with the oral, dual ET(A)/ET(B) receptor antagonist, bosentan has been demonstrated to improve the cardiopulmonary haemodynamics, exercise capacity, quality-of-life and survival in adult patients with PAH. Specific ET(A) antagonists may also present the same beneficial profile. Recent experience with bosentan in paediatric patients with PAH indicates that the results obtained in adult patients may be extrapolated to children, thus offering a safe and effective therapy that is easy to administer.

Topics: Administration, Oral; Adult; Antihypertensive Agents; Bosentan; Calcium Channel Blockers; Child; Epoprostenol; Humans; Hypertension, Pulmonary; Iloprost; Nitric Oxide; Phosphodiesterase Inhibitors; Receptors, Endothelin; Sulfonamides; Vasodilator Agents

Pulmonary arterial hypertension (PAH) is characterized by vasoconstriction and smooth muscle cell proliferation of the pulmonary arterioles, as well as in situ thrombosis of the small pulmonary arteries. Prostacyclin is involved in PAH vascular remodeling. It is unclear if decreased prostacyclin in the lungs is a cause or a consequence of PAH, but the relative lack of prostacyclin and its positive effects on the pulmonary vascular bed support the theory that long-term prostacyclin replacement is effective. Current therapies based on evidence-based medicine include epoprostenol, treprostinil, iloprost, and beraprost, each with limitations based on the drugs' inherent properties and administration route. Treatment of PAH by inhibiting multiple pathways concurrently may produce additive benefit. Because prostacyclin therapy is not curative and does not normalize pulmonary hemodynamics in the majority of cases, combining a prostacyclin with other PAH agents may be a promising approach.

Topics: Antihypertensive Agents; Clinical Trials as Topic; Drug Therapy, Combination; Epoprostenol; Humans; Hypertension, Pulmonary; Iloprost; Vasodilator Agents

The improved understanding of the pathophysiology of pulmonary vascular diseases over the last decade has brought with it significant changes in disease management. Newer therapies have targeted the cardinal features of pulmonary hypertension, which include pulmonary vasoconstriction and vascular remodelling. In addition to prostacyclin, which had been the mainstay of therapy until recently, other available drugs include other prostacyclin analogues, endothelin receptor antagonists and phosphodiesterase inhibitors. This review will discuss some of the evidence for their use and will look towards the future in the search of treatments that may ultimately modify and even reverse the disease process.

Topics: Adult; Antihypertensive Agents; Arginine; Bosentan; Child; Drug Therapy, Combination; Epoprostenol; Humans; Hypertension, Pulmonary; Iloprost; Nitric Oxide; Phosphodiesterase Inhibitors; Platelet Aggregation Inhibitors; Sulfonamides

Pulmonary arterial hypertension (PAH) is associated with changes in vascular tone as well as vascular structure, with the relative contribution of each dependent upon the etiology of the increased vascular resistance. Prostacyclin treatment has markedly improved both the therapeutic options and the prognosis of PAH. The beneficial effect of prostacyclin in PAH is linked to the powerful vasodilating capacity and, even more importantly, to the inhibition of platelet aggregation, smooth muscle proliferation and antiinflammatory actions. Since prostacyclin has a very short plasma half-life, continuous intravenous administration via a portable infusion pump must be carried out. Because of the complexity of the delivery and the associated complications, intravenous prostacyclin (epoprostenol) therapy is restricted to patients with late NYHA Class III and Class IV and thus alternative modes of delivery in less advanced PAH are desirable. Recent clinical studies with more stable prostacyclin analogs such as subcutaneously delivered treprostinil, orally active beraprost and aerosolized iloprost have demonstrated beneficial effects of each of these prostanoids, especially in NYHA Class II and III patients and, therefore, these agents should be considered first for prostanoid therapy in the early stages of PAH. Prostaglandins may be more effective in conjunction with endothelin receptor antagonists or phosphodiesterase inhibitors and an increasing number of studies are now addressing the combined efficiency and safety of these combinations. This update will focus on the current development status of PAH therapy with prostacyclin and its analogs. Special attention will be accorded to the selection of patients for prostanoid therapy, therapy monitoring and improvement of therapeutic efficacy by addition of other new therapeutic agents to prostaglandins. Survival benefits and special aspects of bridging-to-transplant therapy are also important aspects of the review.

Topics: Antihypertensive Agents; Clinical Trials as Topic; Epoprostenol; Humans; Hypertension, Pulmonary; Iloprost; Pulmonary Circulation; Treatment Outcome

Past medical therapy for pulmonary arterial hypertension included the use of calcium-channel antagonists in acute vasoreactive subjects and oral anticoagulants and continuous intravenous administration of epoprostenol in the more severe cases. Recently, the thromboxane inhibitor terbogrel, the prostacyclin analogues treprostinil, beraprost and iloprost, and the endothelin receptor antagonist bosentan have been tested in clinical trials in >1,100 patients. Except for terbogrel, all compounds improved the mean exercise capacity by different degrees, as assessed by the 6-min walk test. In the evaluation of the clinical relevance of exercise capacity improvements, additional elements need to be considered, such as baseline functional class and concomitant favourable effects on combined clinical events (including hospitalisations, mortality and rescue therapies), quality of life and haemodynamics. No trials have shown effects on mortality, as the study protocols were not designed for assessing this end-point. Each new compound presents side-effects that are unpredictable in the individual patient and require appropriate attention upon treatment initiation and maintenance. These new therapeutic options will be available in the near future and will allow tailoring of the most appropriate treatment to the single patient, according to an individualised benefit-to-risk ratio.

Topics: Dose-Response Relationship, Drug; Drug Administration Schedule; Epoprostenol; Female; Humans; Hypertension, Pulmonary; Iloprost; Male; Prognosis; Pyridines; Randomized Controlled Trials as Topic; Severity of Illness Index; Survival Rate; Treatment Outcome; Vasodilator Agents

Prostacyclin is a substance produced by endothelial cells that induces vasodilation and inhibition of platelet aggregation and of vascular cell migration and proliferation. A dysregulation of the prostacyclin metabolic pathways has been shown in patients with pulmonary arterial hypertension. The clinical use of prostacyclin has been made possible by the synthesis of stable analogues that possesses different pharmacokinetic properties but share similar pharmacodynamic effects. The greatest experience has been collected with intravenous epoprostenol while other compounds like subcutaneous UT-15, inhaled iloprost and oral beraprost are currently in different stages of clinical development. Although favorable results have been reported for each compound, different benefit-to-side effects profiles characterize the various modalities of the administration.

Topics: Epoprostenol; Humans; Hypertension, Pulmonary; Iloprost; Vasodilation; Vasodilator Agents

Advances in the understanding of the molecular and cellular pathogeneses of PPH have led clinicians beyond simple pulmonary vasodilation as the only treatment for PPH and to a realization that what were previously believed to be irreversible vascular lesions may, in fact, be reversible. The development of agents that target the known endothelial and nonendothelial defects in patients with PPH is well underway. Clinicians are witnessing an exciting new era for physicians and patients dealing with this disease.

Topics: Animals; Antihypertensive Agents; Endothelin Receptor Antagonists; Endothelins; Endothelium, Vascular; Epoprostenol; Humans; Hypertension, Pulmonary; Nitric Oxide; Vasodilator Agents

Pulmonary arterial hypertension (PAH) is a progressive and life-threatening disease characterized by elevated pulmonary vascular resistance, which results in right-heart failure. We present a case of interferon (IFN)-α-induced PAH developed after living donor liver transplantation. Although IFN is categorized as a "possible" risk factor for PAH in the current international classification, it is still under recognized. Moreover, the prognosis of IFN-induced PAH is poor in the limited number of published cases. In our case, we achieved good outcome by the withdrawal of IFN and administration of combination therapy using tadalafil, beraprost, and treprostinil. Since IFN is an important treatment option in current medical therapy, its contribution to the pathogenesis of PAH should be taken into consideration. In conclusion, our case suggests the importance of PAH screening in patients treated with IFN.

Topics: Antihypertensive Agents; Arterial Pressure; Drug Therapy, Combination; Epoprostenol; Humans; Hypertension, Pulmonary; Immunologic Factors; Interferon-alpha; Liver Transplantation; Living Donors; Male; Middle Aged; Pulmonary Artery; Tadalafil; Treatment Outcome

The heterozygous loss of function mutations in the Type II bone morphogenetic protein receptor (BMPR-II), a member of the transforming growth factor (TGF-β) receptor family, underlies the majority of familial cases of pulmonary arterial hypertension (PAH). The TGF-β1 pathway is activated in PAH, and inhibitors of TGF-β1 signaling prevent the development and progression of PAH in experimental models. However, the effects of currently used therapies on the TGF-β pathway remain unknown. Prostacyclin analogs comprise the first line of treatment for clinical PAH. We hypothesized that these agents effectively decrease the activity of the TGF-β1 pathway. Beraprost sodium (BPS), a prostacyclin analog, selectively inhibits proliferation in a dose-dependent manner in murine primary pulmonary arterial smooth muscle cells (PASMCs) harboring a pathogenic BMPR2 nonsense mutation in both the presence and absence of TGF-β1 stimulation. Our study demonstrates that this agent inhibits TGF-β1-induced SMAD-dependent and SMAD-independent signaling via a protein kinase A-dependent pathway by reducing the phosphorylation of SMADs 2 and 3 and p38 mitogen-activated protein kinase proteins. Finally, in a monocrotaline-induced rat model of PAH, which is associated with increased TGF-β signaling, this study confirms that treprostinil, a stable prostacyclin analog, inhibits the TGF-β pathway by reducing SMAD3 phosphorylation. Taken together, these data suggest that prostacyclin analogs inhibit dysregulated TGF-β signaling in vitro and in vivo, and reduce BMPR-II-mediated proliferation defects in mutant mice PASMCs.

Topics: Animals; Bone Morphogenetic Protein Receptors, Type II; Cell Proliferation; Codon, Nonsense; Epoprostenol; Familial Primary Pulmonary Hypertension; HEK293 Cells; Humans; Hypertension, Pulmonary; Lung; Male; MAP Kinase Signaling System; Mice; Monocrotaline; Myocytes, Smooth Muscle; Phosphorylation; Protein Serine-Threonine Kinases; Rats; Rats, Sprague-Dawley; Receptor, Transforming Growth Factor-beta Type II; Receptors, Transforming Growth Factor beta; Smad3 Protein; Transforming Growth Factor beta1

Prostacyclin (PGI2) and its mimetics (iloprost, treprostinil, beraprost and MRE-269) are potent vasodilators (via IP-receptor activation) and a major therapeutic intervention for pulmonary hypertension (PH). These PGI2 mimetics have anti-proliferative and potent vasodilator effects on pulmonary vessels. We compared the relaxant effects induced by these recognized IP-agonists in isolated human pulmonary arteries (HPA) and veins (HPV). In addition, using selective antagonists, the possible activation of other prostanoid relaxant receptors (DP, EP4) was investigated. Iloprost and treprostinil were the more potent relaxant agonists when both vessels were analyzed. HPA were significantly more sensitive to iloprost than to treprostinil, pEC50 values: 7.94±0.06 (n=23) and 6.73±0.08 (n=33), respectively. In contrast, in HPV these agonists were equipotent. The relaxations induced by treprostinil were completely or partially inhibited by IP-antagonists in HPA or HPV, respectively. The effects of the IP-agonists were not significantly modified by the EP4 antagonist. Finally, DP-antagonists inhibited the relaxations induced by treprostinil in HPV, suggesting that the DP-receptor plays a role in treprostinil-induced relaxation in the HPV. These data suggest that iloprost and treprostinil should be the most effective clinically available agonists to decrease pulmonary vascular resistance and to prevent oedema formation (by similar decrease in HPA and HPV resistance) in PH patients.

Topics: Acetates; Aged; Drug Evaluation, Preclinical; Epoprostenol; Female; Humans; Iloprost; In Vitro Techniques; Inhibitory Concentration 50; Male; Middle Aged; Molecular Mimicry; Pulmonary Artery; Pulmonary Veins; Pyrazines; Receptors, Epoprostenol; Receptors, Immunologic; Receptors, Prostaglandin; Receptors, Prostaglandin E, EP4 Subtype; Vasodilation; Vasodilator Agents

Among pleiotropic effects, the capacity of prostaglandin I(2) (PGI(2)) analogues to affect adaptive immunity remains poorly characterised. The purpose of this study was to assess whether PGI(2) analogues could affect T helper (Th) cell responses in patients with systemic sclerosis (SSc) and healthy donors (HD).. Peripheral blood mononuclear cells (PBMC) were obtained from 33 patients with SSc and 29 HD. Cytokine levels in PBMC and monocyte/CD4 T cell cultures were quantified by immunoassays. The frequencies of interleukin (IL)-17A, IL-22, interferon γ (IFNγ) and IL-4-producing CD4 T cells were assessed by multiparametric flow cytometry. Selective receptor antagonists, cytokine blocking antibodies and signalling protein inhibitors were used to identify the receptors and signalling pathways mediating PGI(2) analogue effects.. Th17 and Th22 cells were more abundant in individuals with SSc than in HD. PGI(2) analogues (iloprost, treprostinil and beraprost) significantly increased IL-17A and IL-22 in vitro while decreasing IFNγ production both in SSc and HD PBMC. These effects relied on the specific expansion of Th17 and Th22 and inhibition of Th1 cells. The enhanced Th17 cell responses depended on increased IL-23 production by monocytes, involved the IP prostacyclin receptor and required protein kinase A activation. Importantly, in vivo administration of iloprost in individuals with SSc presenting with digital ulcers resulted in a significant increase in the frequency of Th17 cells.. These findings demonstrate that PGI(2) analogues affect Th cell differentiation/expansion programmes, favouring Th17 and inhibiting Th1 cell responses in SSc. The impact of these changes on the disease course needs to be taken into consideration and further exploited to improve SSc.

Topics: Adaptive Immunity; Adult; Aged; Aged, 80 and over; Antihypertensive Agents; Cell Proliferation; Cells, Cultured; Cyclic AMP-Dependent Protein Kinases; Epoprostenol; Female; Humans; Iloprost; Interferon-gamma; Interleukin-17; Interleukin-22; Interleukin-23 Subunit p19; Interleukins; Male; Middle Aged; Monocytes; Platelet Aggregation Inhibitors; Scleroderma, Systemic; Th1 Cells; Th17 Cells; Young Adult

Although treatment for asthma control has improved a lot recently, refractory asthma is still a challenge for clinicians. Evidence revealed that anti-tumor necrosis factor (TNF)-α therapy may have potential in treating refractory asthma. Recently in an animal model, prostaglandin I(2) (PGI(2)) analogues can suppress the cardinal feature of asthma. However, whether PGI(2) analogues can regulate TNF-α expression in monocytes and the mechanism is not well-known.. The human monocytes were pretreated with beraprost, iloprost and treprostinil, three PGI(2) analogues, before stimulation with lipopolysaccharide (LPS). TNF-α concentration of the cell supernatants was measured by ELISA. Intracellular signaling was investigated by Western blot.. PGI(2) analogues suppressed LPS-induced TNF-α expression in THP-1 cells. CAY10449, an I prostanoid receptor antagonist, could reverse these effects. Beraprost increased intracellular cAMP level in THP1 cells. Forskolin, an adenylyl cyclase activator, could confer similar effect. LPS-induced TNF-α expression in THP-1 cells could be reversed by mitogen-activator protein kinase (MAPK)-p38, extracellular signal-related kinase (ERK) and c-Jun N-terminal kinase (JNK) inhibitors. Western blot revealed that beraprost suppressed MAPK phospho-p38, phosphor-JNK and phosphor-ERK expression.. PGI(2) analogues suppressed LPS-induced TNF-α expression in THP-1 cells via the IP receptor-cAMP and the MAPK pathways. PGI(2) analogues may have potentiality to treat asthma.

Topics: Animals; Antihypertensive Agents; Cell Line; Epoprostenol; Humans; Iloprost; MAP Kinase Signaling System; Mitogen-Activated Protein Kinases; Monocytes; PPAR gamma; Tumor Necrosis Factor-alpha; Vasodilator Agents

Selexipag [2-{4-[(5,6-diphenylpyrazin-2-yl)(isopropyl)amino]butoxy}-N-(methylsulfonyl)acetamide] is an orally available prostacyclin (PGI(2)) receptor (IP receptor) agonist that is chemically distinct from PGI(2) and is in clinical development for the treatment of pulmonary arterial hypertension. Selexipag is highly selective for the human IP receptor in vitro, whereas analogs of PGI(2) can activate prostanoid receptors other than the IP receptor. The goal of this study was to determine the impact of selectivity for the IP receptor on gastric function by measuring 1) contraction of rat gastric fundus ex vivo and 2) the rates of gastric emptying and intestinal transport in response to selexipag in comparison with other PGI(2) analogs. The rat gastric fundus expresses mRNA encoding multiple prostanoid receptors to different levels: prostaglandin E receptor 1 (EP(1)) > prostaglandin E receptor 3 (EP(3)), IP receptor > prostaglandin D(2) receptor 1, thromboxane receptor. Selexipag and metabolite {4-[(5,6-diphenylpyrazin-2-yl)(isopropyl)amino]butoxy}acetic acid (ACT-333679) did not contract gastric fundus at concentrations up to 10(-3) M. In contrast, the PGI(2) analogs iloprost and beraprost evoked concentration-dependent contraction of gastric fundus. Contraction to treprostinil was observed at high concentration (10(-4) M). Contraction to all PGI(2) analogs was mediated via activation of EP(3) receptors, although EP(1) receptors also contributed to the contraction of gastric fundus to iloprost and beraprost. Antagonism of IP receptors did not affect responses. Oral selexipag did not significantly alter gastric function in vivo, as measured by rates of stomach emptying and intestinal transport, whereas beraprost slowed gastrointestinal transport. The high functional selectivity of selexipag and ACT-333679 for the IP receptor precludes a stimulatory action on gastric smooth muscle and may help minimize gastric side effects such as nausea and vomiting.

Topics: Acetamides; Animals; Dinoprostone; Dose-Response Relationship, Drug; Epoprostenol; Gastric Emptying; Gastrointestinal Transit; Humans; Iloprost; Male; Muscle Contraction; Pulmonary Artery; Pyrazines; Rats; Receptors, Epoprostenol; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Stomach

Pulmonary arterial hypertension (PAH) is defined as a group of diseases characterised by a progressive increase of pulmonary vascular resistance leading to right ventricular failure and death. A dysregulation of prostacyclin metabolic pathways has been demonstrated in patients with PAH and in experimental models. Recently, therapy with continuous intravenous prostacyclin (epoprostenol) has been shown to improve symptoms and prognosis in New York Heart Association (NYHA) functional class III and IV patients with different types of PAH. However, epoprostenol administration requires invasive methods with a permanent intravenous catheter and is associated with several side effects and potentially serious complications. Other modes of prostacyclin therapies are being considered using stable prostacyclin analogues administered by inhalation (iloprost), subcutaneously (treprostinil) or orally (beraprost). Over the last years, different multicenter international double-blind trials have demonstrated the efficacy of those novel prostacyclin analogues in PAH compared to conventional therapy promising a better future for these patients.

Topics: Antihypertensive Agents; Epoprostenol; Humans; Hypertension, Pulmonary; Iloprost; Vasodilator Agents

Primary pulmonary hypertension is characterized by increased pulmonary vascular resistance and smooth muscle proliferation. Stable analogs are increasingly being used to treat this disease, although no data exists comparing their effects on proliferation. We therefore investigated the antiproliferative activity of several prostacyclin (PGI(2)) analogs on human pulmonary arterial smooth muscle cells, including UT-15 and iloprost, analogs that have recently completed successful clinical trials. Serum-induced proliferation, as assessed by [(3)H]thymidine incorporation (30 h) or cell number (48 h), was significantly inhibited with a 10-fold difference in potency, ranking in effectiveness UT-15 > iloprost > cicaprost > beraprost. Effects were reversed by the adenylyl cyclase inhibitor, 2,5'dideoxyadenosine (DDA) but not SQ22536. Intracellular cyclic AMP (cAMP) was elevated by all analogs and inhibited by DDA, although SQ22536 was a highly variable inhibitor, suggesting that different pathways might mediate cAMP generation. UT-15 produced a significantly larger and more sustained increase in cAMP compared with other analogs, with iloprost being the weakest elevator. Thus, PGI(2) analogs potently inhibit proliferation of human pulmonary artery, probably via a cAMP-dependent pathway, although cAMP elevation in itself is not a good predictor of antiproliferative potency.

Topics: Adenylyl Cyclase Inhibitors; Adenylyl Cyclases; Cell Division; Cells, Cultured; Cyclic AMP; Enzyme Inhibitors; Epoprostenol; Humans; Iloprost; Molecular Structure; Muscle, Smooth, Vascular; Platelet-Derived Growth Factor; Pulmonary Artery