Prostacyclin Analogue Research Articles

Outcome of patients with severe PH due to lung disease with and without targeted therapy.

Pulmonary hypertension (PH) can occur in patients with lung disease and worsen prognosis. Endothelin receptor antagonists, phosphodiesterase 5-inhibitors, and prostacyclin analogs, referred to as targeted therapy, have not been shown in a limited number of controlled clinical studies to improve exercise capacity in these patients. Possibly targeted therapy could be of benefit in patients with severe PH due to lung disease, but this subgroup is not well studied. To analyze influence of PH severity and use of targeted therapy on exercise capacity and survival in patients with PH due to lung disease. Consecutive patients with PH (mean pulmonary artery pressure ≥25mmHg at rest) due to lung disease diagnosed by right heart catheterization between 1/2005 and 9/2011 were retrospectively included. Severe PH was defined as mean pulmonary artery pressure ≥35mmHg. Patients were followed until 4/2012 for exercise capacity, survival, and targeted therapy use. Patients with severe PH (n=40) received significantly more often targeted therapy compared to the 32 patients with less severe PH (65% vs. 25%, P=0.001). Survival was not significantly different between these groups (P=0.310). Patients on targeted therapy were older, more often female, and had worse hemodynamic impairment, but significantly higher estimated 1-, 3-, and 5-year survival rates compared to untreated patients (97%, 81%, and 75% vs. 83%, 54%, and 19%, respectively; P=0.002). This effect was mainly driven by the patients with severe PH, in whom the survival advantage was statistically significant on subgroup analysis (HR 0.182, P=0.002). Exercise capacity was not significantly altered in any patient group. Patients with severe PH due to lung disease may have a survival benefit from targeted therapy compared to untreated patients with less severe PH. Prospective clinical trials utilizing targeted therapy and long-term endpoints are justified in this patient group.

The heterogeneity of clinical practice patterns among an international cohort of pulmonary arterial hypertension experts.

The extent to which pulmonary arterial hypertension (PAH) experts share common practice patterns that are in alignment with published expert consensus recommendations is unknown. Our objective was to characterize the clinical management strategies used by an international cohort of self-identified PAH experts. A 32-item questionnaire composed mainly of rank order or Likert scale questions was distributed via the Internet (August 5, 2013, through January 20, 2014) to four international pulmonary vascular disease organizations. The survey respondents (N = 105) were field experts reporting 11.6 ± 8.7 years of PAH experience. Likert scale responses (1 = disagree, 7 = agree) were 3.0-5.0, indicating a disparity in opinions, for 78% of questions. Respondent (dis)agreement scores were 4.4 ± 2.2 for use of expert recommendations to determine catheterization timing in PAH. For PAH patients without cardiogenic shock or known vasoreactivity status, the most and least preferred first-line therapies (1 = most preferred, 5 = least preferred) were phosphodiesterase type 5 inhibitors (PDE-Vi) and subcutaneous prostacyclin analogues, respectively (1.4 ± 0.8 vs. 4.0 ± 1.1; P < 0.05). Compared with US-practicing clinicians (N = 46), non-US-practicing clinicians (N = 57) favored collaboration between cardiology and pulmonary medicine for clinical decision making (1 = disagree, 7 = agree; 3.1 ± 2.2 vs. 4.8 ± 2.2; P < 0.0001) and PDE-Vi (6.5% vs. 22.4%) as first-line therapy for PAH patients with cardiogenic shock but were less likely to perform vasoreactivity testing in patients with lung disease-induced pulmonary hypertension (4.3 ± 2.1 vs. 2.2 ± 1.6; P < 0.0001). In conclusion, practice patterns among PAH experts diverge from consensus recommendations and differ by practice location, suggesting that opportunity may exist to improve care quality for this highly morbid cardiopulmonary disease.

Enhancement of mouse embryo development and implantation by a novel prostacyclin-producing co-culture system -- implication to human IVF

Iloprost, a stable analog of prostacyclin has been reported to enhance human IVF success (1). Natural prostacyclin has short half life (3-8 minutes), which renderes experiments with naturally occurring prostacyclin extremely difficult. Our objective was to test a novel de-novo prosatacyclin-producing co-culture system and to determine its impact on embryo development and implantation.

Phosphodiesterase 5 inhibitors augment UT-15C-stimulated ATP release from erythrocytes of humans with pulmonary arterial hypertension.

Both prostacyclin analogs and phosphodiesterase 5 (PDE5) inhibitors are effective treatments for pulmonary arterial hypertension (PAH). In addition to direct effects on vascular smooth muscle, prostacyclin analogs increase cAMP levels and ATP release from healthy human erythrocytes. We hypothesized that UT-15C, an orally available form of the prostacyclin analog, treprostinil, would stimulate ATP release from erythrocytes of humans with PAH and that this release would be augmented by PDE5 inhibitors. Erythrocytes were isolated and the effect of UT-15C on cAMP levels and ATP release were measured in the presence and absence of the PDE5 inhibitors, zaprinast or tadalafil. In addition, the ability of a soluble guanylyl cyclase inhibitor to prevent the effects of tadalafil was determined. Erythrocytes of healthy humans and humans with PAH respond to UT-15C with increases in cAMP levels and ATP release. In both groups, UT-15C-induced ATP release was potentiated by zaprinast and tadalafil. The effect of tadalafil was prevented by pre-treatment with an inhibitor of soluble guanylyl cyclase in healthy human erythrocytes. Importantly, UT-15C-induced ATP release was greater in PAH erythrocytes than in healthy human erythrocytes in both the presence and the absence of PDE5 inhibitors. The finding that prostacyclin analogs and PDE5 inhibitors work synergistically to enhance release of the potent vasodilator ATP from PAH erythrocytes provides a new rationale for the co-administration of these drugs in this disease. Moreover, these results suggest that the erythrocyte is a novel target for future drug development for the treatment of PAH.

Liposomal nanoparticles encapsulating iloprost exhibit enhanced vasodilation in pulmonary arteries.

Prostacyclin analogues are standard therapeutic options for vasoconstrictive diseases, including pulmonary hypertension and Raynaud’s phenomenon. Although effective, these treatment strategies are expensive and have several side effects. To improve drug efficiency, we tested liposomal nanoparticles as carrier systems. In this study, we synthesized liposomal nanoparticles tailored for the prostacyclin analogue iloprost and evaluated their pharmacologic efficacy on mouse intrapulmonary arteries, using a wire myograph. The use of cationic lipids, stearylamine, or 1,2-di-(9Z-octadecenoyl)-3-trimethylammonium-propane (DOTAP) in liposomes promoted iloprost encapsulation to at least 50%. The addition of cholesterol modestly reduced iloprost encapsulation. The liposomal nanoparticle formulations were tested for toxicity and pharmacologic efficacy in vivo and ex vivo, respectively. The liposomes did not affect the viability of human pulmonary artery smooth muscle cells. Compared with an equivalent concentration of free iloprost, four out of the six polymer-coated liposomal formulations exhibited significantly enhanced vasodilation of mouse pulmonary arteries. Iloprost that was encapsulated in liposomes containing the polymer polyethylene glycol exhibited concentration-dependent relaxation of arteries. Strikingly, half the concentration of iloprost in liposomes elicited similar pharmacologic efficacy as nonencapsulated iloprost. Cationic liposomes can encapsulate iloprost with high efficacy and can serve as potential iloprost carriers to improve its therapeutic efficacy.

A prostacyclin analog prevents the regression of renal microvascular network by inhibiting mitochondria-dependent apoptosis in the kidney of rat progressive glomerulonephritis

We have previously demonstrated that renoprotective effects of a prostacyclin analog, beraprost sodium, on the kidney of anti-glomerular basement membrane glomerulonephritis (GN) rats. The aim of this study is to address the renoprotection mechanism of beraprost sodium, especially in the terminal stage of GN. Beraprost sodium was orally administrated from 2 to 7 weeks after induction of GN, and renal function, morphology, protein and mRNA levels were analyzed. We found the beraprost sodium treatment suppressed the structural regression of renal microvascular network and decline of renal blood flow occurred in the kidney of GN rats. To address the mechanism of the structural maintenance, we focused on apoptosis because the increased number of apoptotic renal microvascular endothelial cells and tubular epithelial cells was observed in the kidneys of GN rats as compared with normal and beraprost sodium treated rats. Protein and mRNA analyses demonstrated that mitochondria-dependent apoptotic pathway was activated in the kidneys of GN rats, and beraprost sodium suppressed the activation by modulating the expression patterns of pro- and anti-apoptotic factors. These results suggest that inhibition of mitochondria-dependent apoptosis of renal cells in GN kidney and consequent maintenance of renal functional structures, including microvascular network might contribute to the renoprotective effect of beraprost sodium in GN.

Inhibition of phosphodiesterase 2 augments cGMP and cAMP signaling to ameliorate pulmonary hypertension.

Pulmonary hypertension (PH) is a life-threatening disorder characterized by increased pulmonary artery pressure, remodeling of the pulmonary vasculature, and right ventricular failure. Loss of endothelium-derived nitric oxide (NO) and prostacyclin contributes to PH pathogenesis, and current therapies are targeted to restore these pathways. Phosphodiesterases (PDEs) are a family of enzymes that break down cGMP and cAMP, which underpin the bioactivity of NO and prostacyclin. PDE5 inhibitors (eg, sildenafil) are licensed for PH, but a role for PDE2 in lung physiology and disease has yet to be established. Herein, we investigated whether PDE2 inhibition modulates pulmonary cyclic nucleotide signaling and ameliorates experimental PH. The selective PDE2 inhibitor BAY 60-7550 augmented atrial natriuretic peptide- and treprostinil-evoked pulmonary vascular relaxation in isolated arteries from chronically hypoxic rats. BAY 60-7550 prevented the onset of both hypoxia- and bleomycin-induced PH and produced a significantly greater reduction in disease severity when given in combination with a neutral endopeptidase inhibitor (enhances endogenous natriuretic peptides), trepostinil, inorganic nitrate (NO donor), or a PDE5 inhibitor. Proliferation of pulmonary artery smooth muscle cells from patients with pulmonary arterial hypertension was reduced by BAY 60-7550, an effect further enhanced in the presence of atrial natriuretic peptide, NO, and treprostinil. PDE2 inhibition elicits pulmonary dilation, prevents pulmonary vascular remodeling, and reduces the right ventricular hypertrophy characteristic of PH. This favorable pharmacodynamic profile is dependent on natriuretic peptide bioactivity and is additive with prostacyclin analogues, PDE5 inhibitor, and NO. PDE2 inhibition represents a viable, orally active therapy for PH.

Clinical utility of treprostinil in the treatment of pulmonary arterial hypertension: an evidence-based review.

Pulmonary arterial hypertension (PAH) remains a progressive disease without a cure, despite the development of several treatment options over the past several decades. Its management strategy consists of the endothelin receptor antagonists (ambrisentan, bosentan, macitentan), phosphodiesterase-5 inhibitors (sildenafil, tadalafil, vardenafil), and prostacyclin analogs (epoprostenol, treprostinil, iloprost). Treprostinil, a stable prostacyclin analog, displays vasodilatory effects in the pulmonary vasculature, as well as antiplatelet aggregation properties. Clinical practice guidelines recommend oral endothelin receptor antagonist or phosphodiesterase inhibitor therapy in mild to moderate PAH. Epoprostenol is specifically suggested as first-line therapy in moderate to severe PAH patients (ie, World Health Organization/New York Heart Association functional class III–IV). However, treprostinil may be an alternative option in these severe PAH patients. The longer half-life and stability at room temperature with treprostinil may be associated with lower risk of pulmonary hemodynamic worsening as a result of abrupt infusion discontinuation and less frequent drug preparation. These characteristics make treprostinil an attractive alternative to continuous infusion of epoprostenol, due to convenience and patient safety. The purpose of this review is to evaluate the safety and efficacy of continuous infusion of treprostinil as well as the inhaled and oral routes of administration in PAH.

OP0091 A Retrospective Look at the Recurrence of Digital Ulcers in Patients with Scleroderma after Discontinuation of Oral Treprostinil

BackgroundIschemic digital ulcers (DU) are a frequent complication in systemic sclerosis, estimated to occur in over 40% of patients. Treprostinil diethanolamine, a newer prostacyclin analog that has been developed for...

FRI0491 Possible Role of Iloprost in Vivo on T-Lymphocyte Regulation Pathway in Early Systemic Sclerosis (ESSC)

BackgroundSystemic Sclerosis (SSc) is an autoimmune disease characterized by fibrosis and vasculopathy. In patients with active SSc increasing values of the Th17 subset and of pro-fibrotic interleukins such as IL6,...

Prostacyclin analogue beraprost inhibits cardiac fibroblast proliferation depending on prostacyclin receptor activation through a TGF β-Smad signal pathway.

Previous studies showed that prostacyclin inhibited fibrosis. However, both receptors of prostacyclin, prostacyclin receptor (IP) and peroxisome proliferator-activated receptor (PPAR), are abundant in cardiac fibroblasts. Here we investigated which receptor was vital in the anti-fibrosis effect of prostacyclin. In addition, the possible mechanism involved in protective effects of prostacyclin against cardiac fibrosis was also studied. We found that beraprost, a prostacyclin analogue, inhibited angiotensin II (Ang II)-induced neonatal rat cardiac fibroblast proliferation in a concentration-dependent and time-dependent manner. Beraprost also suppressed Ang II-induced collagen I mRNA expression and protein synthesis in cardiac fibroblasts. After IP expression was knocked down by siRNA, Ang II-induced proliferation and collagen I synthesis could no longer be rescued by beraprost. However, treating cells with different specific inhibitors of PPAR subtypes prior to beraprost and Ang II stimulation, all of the above attenuating effects of beraprost were still available. Moreover, beraprost significantly blocked transforming growth factor β (TGF β) expression as well as Smad2 phosphorylation and reduced Smad-DNA binding activity. Beraprost also increased phosphorylation of cAMP response element binding protein (CREB) at Ser133 in the nucleus. Co-immunoprecipitation analysis revealed that beraprost increased CREB but decreased Smad2 binding to CREB-binding protein (CBP) in nucleus. In conclusion, beraprost inhibits cardiac fibroblast proliferation by activating IP and suppressing TGF β-Smad signal pathway.

Functional Prostacyclin Synthase Promoter Polymorphisms. Impact in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a progressive disease characterized by elevated pulmonary artery pressure, vascular remodeling, and ultimately right ventricular heart failure. PAH can have a genetic component (heritable PAH), most often through mutations of bone morphogenetic protein receptor 2, and idiopathic and associated forms. Heritable PAH is not completely penetrant within families, with approximately 20% concurrence of inactivating bone morphogenetic protein receptor 2 mutations and delayed onset of PAH disease. Because one of the treatment options is using prostacyclin analogs, we hypothesized that prostacyclin synthase promoter sequence variants associated with increased mRNA expression may play a protective role in the bone morphogenetic protein receptor 2 unaffected carriers. To characterize the range of prostacyclin synthase promoter variants and assess their transcriptional activities in PAH-relevant cell types. To determine the distribution of prostacyclin synthase promoter variants in PAH, unaffected carriers in heritable PAH families, and control populations. Polymerase chain reaction approaches were used to genotype prostacyclin synthase promoter variants in more than 300 individuals. Prostacyclin synthase promoter haplotypes' transcriptional activities were determined with luciferase reporter assays. We identified a comprehensive set of prostacyclin synthase promoter variants and tested their transcriptional activities in PAH-relevant cell types. We demonstrated differences of prostacyclin synthase promoter activities dependent on their haplotype. Prostacyclin synthase promoter sequence variants exhibit a range of transcriptional activities. We discovered a significant bias for more active prostacyclin synthase promoter variants in unaffected carriers as compared with affected patients with PAH.

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Background and aims: Patients with Acute liver failure (ALF) are pro-thrombotic and hence prone to circuit clotting leading to treatment downtimes on CRRT. In patients with ALF, heparin may either be contraindicated(thrombocytopenia)or insufficient (pro-coagulant). Epoprostenol, an anti-platelet agent could be an alternative to heparin to prevent circuit clotting. Aims: To investigate efficacy and safety of Epoprostenol(synthetic prostacyclin analogue)as sole anti-haemostatic agent used for circuit patency during CRRT in patients with ALF. Methods: Prospective study of children with ALF admitted to PICU receiving CRRT over a 4 year period. Patients were stratified according to the used anticoagulant-Epoprostenol PGI (2) group (n=45) and non-epoprostenol group (n=26). Efficacy was measured by filter life and mortality. Safety was assessed by number of bleeding episodes during CVVH, platelet consumption and hypotensive episodes (requirement for fluids/vasopressors). Results: Seventy-one ALF patients underwent CRRT for a total of 11659 hours utilising 393 filters (5.5 circuits/patient). Epoprostenol was used in 45 patients at the dose of 4ng/kg/min administered pre-filter for a total of 6761 hours. In the non-epoprostenol group, 36 patients underwent CRRT for 4898 hours using unfractionated heparin. Median filter life was 37.5 hours in epoprostenol group and 24.5 hours in non-epoprostenol group (p<0.001). 3/45 (6.7%) patients on Epoprostenol and 9/26 (34.6 %) in non-epoprostenol group experienced bleeding episodes (0.44 episode per 1000 patient hours of treatment). Platelet consumption was significantly lower in epoprostenol group(938 ml versus1913ml). Therapeutic intervention for hypotension was required in significantly lower CRRT sessions in Epoprostenol group (8.9% versus 34 %). Despite higher PIM2 scores in Epoprostenol group (62.3%versus 45.7%), mortality was lower in this group (31.1%versus 42.3%). Conclusions: Epoprostenol as the sole anti-hemostatic agent for CRRT increases mean filter life,decreases bleeding risk without increasing risk of hypotension,platelet transfusion or mortality.

Prognostic Value of Echocardiographic Changes in Patients with Pulmonary Arterial Hypertension Receiving Parenteral Prostacyclin Therapy

It is unknown whether the echocardiographic changes observed after treatment of patients with pulmonary arterial hypertension have prognostic value. Subjects with pulmonary arterial hypertension, confirmed by right heart catheterization, who underwent Doppler echocardiography before (baseline) and after 1 year of treatment (follow-up) with parenteral prostacyclin analogues were retrospectively identified. Echocardiographic parameters were measured offline by two investigators. A total of 48 patients were included (mean age, 45 ± 14 years; 83% women). Compared with baseline, follow-up echocardiography showed reductions in right atrial area (mean percentage change, 12 ± 25%; P < .001), right ventricular (RV) basal and middle cavity dimensions (mean percentage change, 8.5 ± 14% [P < .001] and 6.8 ± 17% [P = .005], respectively), and peak tricuspid regurgitant velocity (mean percentage change, 10 ± 14%; P < .001). Tricuspid annular plane systolic excursion (mean percentage change, 36 ± 43%; P < .001) and RV outflow tract time-velocity integral (mean percentage change, 48 ± 66%; P < .001) increased. During a median follow-up period of 52.5 months (interquartile range, 20.5-80 months), 18 patients (37.5%) died, mostly (n = 15 [83%]) from progression of pulmonary arterial hypertension. The changes in RV end-diastolic area (hazard ratio [HR per 10% decrease, 0.73; 95% confidence interval [CI], 0.57-0.93), tricuspid valve regurgitation velocity (HR per 10 cm/sec decrease, 0.58; 95% CI, 0.37-0.89), RV outflow tract velocity-time integral (HR per 10% increase, 0.90; 95% CI, 0.83-0.98), and subjective RV function (HR per 1 unit of improvement [e.g., from moderate to mild], 0.55; 95% CI, 0.31-0.96) were associated with overall mortality. Echocardiographic parameters that estimate RV systolic pressure and assess RV morphology and function improve after 1 year of prostacyclin analogue treatment, and the degree of change has prognostic implications.

Enhanced prostacyclin formation and Wnt signaling in sclerostin deficient osteocytes and bone

We show that prostacyclin production is increased in bone and osteocytes from sclerostin (Sost) knockout mice which have greatly increased bone mass. The addition of prostacyclin or a prostacyclin analog to bone forming osteoblasts enhances differentiation and matrix mineralization of osteoblasts. The increase in prostacyclin synthesis is linked to increases in β-catenin concentrations and activity as shown by enhanced binding of lymphoid enhancer factor, Lef1, to promoter elements within the prostacyclin synthase promoter. Blockade of Wnt signaling reduces prostacyclin production in osteocytes. Increased prostacyclin production by osteocytes from sclerostin deficient mice could potentially contribute to the increased bone formation seen in this condition.

Effects of beraprost sodium, an oral prostacyclin analog, on insulin resistance in patients with type 2 diabetes

Beraprost sodium (BPS) is an orally active prostacyclin analog that is widely used in the treatment of atherosclerotic peripheral arterial disease (PAD). The aim of this study was to evaluate the effects of BPS on the insulin resistance in type 2 diabetic patients with PAD. A euglycemic-hyperinsulinemic clamp study was performed to determine the insulin sensitivity (based on the M/I ratio) before and after 12 weeks’ BPS treatment in 14 patients (12 men; mean age, 68.7 ± 5.5 years) with type 2 diabetes and PAD. While there was no significant change of the BMI or waist circumference, a tendency towards improvement of the M/I ratio and decrease of the HbA1c and serum triglyceride level was observed. Subgroup analyses revealed that the improvement of the M/I ratio was more pronounced in the subgroups with a higher serum triglyceride level and lower value of the M/I ratio at the baseline. Our findings suggest that BPS may improve the insulin resistance in diabetic patients, especially in those with greater degrees of insulin resistance.

Prostacyclin Signaling Boosts NADPH Oxidase 4 in the Endothelium Promoting Cytoprotection and Angiogenesis

Prostacyclin (PGI2) that is released from the vascular endothelium plays an important role in vasodilatation and thrombo-resistance, and it has long been suspected to protect cell survival. How it does so has never been clear. Recently, it has been shown that the NADPH oxidase 4 (Nox4) improves endothelial cell functions and promotes angiogenesis in vivo, but it was not known how to boost Nox4 therapeutically to exploit its protective functions in the vasculature. Here, we identified such a stimulus. The selective and stable prostacyclin receptor (IP-R) agonist cicaprost increases the expression of Nox4 in human endothelial cells of several types, including endothelial progenitor cells. The elevation of cellular cyclic-AMP increased Nox4 expression and H2O2 production and prevented endothelial cell apoptosis. We delineate the intracellular signaling that promotes cytoprotection: Cicaprost acts via the IP-R/protein kinase A (PKA)/cyclic adenosine monophosphate (cAMP) response element binding (CREB) protein pathway. Importantly, the up-regulation of Nox4 by cicaprost also enhanced endothelial cell proliferation, migration, and angiogenesis, with all effects being substantially decreased by Nox4 gene silencing. Finally, cicaprost enhanced the growth of blood vessels into subcutaneous sponges implanted in mice, an effect that was also blocked by Nox4 gene silencing. The prostacyclin analogue cicaprost induces Nox4 via IP receptor-cAMP/PKA/CREB pathway. The activation of this pathway protects endothelial cells and enhances pro-angiogenic activity both in vitro and in vivo. Prostacyclin promotes the up-regulation of Nox4 in endothelial cells, which opens up a novel strategy that protects and enhances endothelial cell functions in cardiovascular disease, such as repair after myocardial infarction or other ischemic conditions.

(392) - The PROSPECT Registry of Pulmonary Arterial Hypertension (PAH): Description of Patients Who Transitioned From Inhaled Prostacyclin to Intravenous Epoprostenol

Tailoring PAH therapy to match patient risk level may improve outcomes. Intensive therapy (ie, continuous intravenous prostacyclin) is recommended for high-risk patients. Epoprostenol for injection (Veletri®; Epo-A), a prostacyclin analog approved for World Health Organization Group 1 PAH, has established efficacy in patients in functional class (FC) III/IV. Here, we describe PROSPECT patients who transitioned from inhaled prostacyclin to Epo-A.

A sustained prostacyclin analog, ONO-1301, attenuates pancreatic fibrosis in experimental chronic pancreatitis induced by dibutyltin dichloride in rats

BackgroundONO-1301, a novel sustained-release prostacyclin agonist, has an anti-fibrotic effect on the lungs, heart, and kidneys that is partly associated with the induction of hepatocyte growth factor (HGF). This study examined the anti-fibrotic effect of ONO-1301 on chronic pancreatitis (CP) progression. MethodsCP was induced in rats in vivo by dibutyltin dichloride (DBTC). Seven days after DBTC injection (day 7), a slow-release form of ONO-1301 (10 mg/kg; ONO-1301–treated group) or vehicle (DBTC-treated group) was injected. On days 14 and 28, we evaluated the histopathological CP score and mRNA expressions of HGF, cytokines, and collagen in the pancreas by real-time RT-PCR. In vitro, monocytes and pancreatic stellate cells (PSCs) were isolated from normal rat spleen and pancreas, respectively. The cytokine and collagen expressions of monocytes and PSCs were detected by real-time RT-PCR, and PSCs proliferation was examined by BrdU assay. ResultsHistopathological CP scores in vivo improved in the ONO-1301–treated group compared to the DBTC-treated group, particularly inflammatory cell infiltration on day 14 and interstitial fibrosis on day 28. HGF mRNA increased significantly after ONO-1301 administration, whereas IL-1β, TNF-α, TGF-β, MCP-1, and collagen mRNA decreased significantly. Cytokine expression in monocytes was suppressed in vitro not only by HGF, but also ONO-1301 alone. However, neither ONO-1301 nor HGF affected the proliferation, or cytokine or collagen expression of PSCs. ConclusionsONO-1301 suppresses pancreatic fibrosis in the DBTC-induced CP model by inhibiting monocyte activity not only with induction of HGF but also by ONO-1301 itself.

Pharmacokinetics of 3 Times a Day Dosing of Oral Treprostinil in Healthy Volunteers

Treprostinil diolamine (oral treprostinil) is an orally available prostacyclin analog that was developed for the treatment of pulmonary arterial hypertension. This study aimed to evaluate the pharmacokinetics (PK), safety, and tolerability of 3 times daily (TID) dosing of oral treprostinil. This was a 9-day, open-label, single-center study in which 19 healthy subjects received 0.5 mg oral treprostinil TID for 7 days. On the morning of day 1, subjects received a single 0.5 mg dose and on days 2-7, subjects received 3 doses of 0.5 mg oral treprostinil with a meal (at approximately 8 AM, 2 PM, and 8 PM). On the morning of day 8, subjects received a final 0.5 mg dose. Intensive 24-hour PK sampling occurred after the AM doses on days 1, 7, and 8. Additional trough plasma samples were collected before the morning and evening doses on days 4, 5, and 6. Nineteen subjects (9 men, 10 women) with a mean age of 35.2 years (range, 20-54 years) were enrolled. The majority of subjects were white (n = 17). The mean (% CVb) Cmax was 0.538 (37%), 0.714 (51%), and 0.559 (45%) ng/mL on days 1, 7, and 8, respectively. After a single dose on day 1 (first dose) and day 8 (last dose), mean (CVb%) AUC0-24 was 2.45 (26%) and 2.96 (28%) h·ng·mL, respectively. The mean (% CVb) steady-state AUC0-24 after TID regimen (on day 7) was 6.53 (34%) h·ng·mL, which was not significantly different from mean AUC0-∞ (7.39 h·ng·mL) on day 1 adjusted for 3 doses. Mean apparent t1/2 was similar on days 1, 7, and 8 (1.1-1.4 hours). Trough concentrations of treprostinil were comparable across study days ranging from 0.046 to 0.053 ng/mL before the AM dose and from 0.27 to 0.39 ng/mL before the evening dose. Steady state was achieved within 2 days of TID dosing. Treprostinil PK after TID dosing of oral treprostinil follows linear kinetics and can be predicted based on PK data after a single dose. Sixteen adverse events occurred in 7 subjects and included prostacyclin related adverse events such as headache, diarrhea, and jaw pain. Three times daily dosing of 0.5 mg oral treprostinil for 7 days was well tolerated in healthy subjects and provided sustained plasma exposure throughout the day at steady state without drug accumulation. This study provides data to support further evaluation of TID dosing regimen of oral treprostinil.