Beraprost Research Articles

Prostaglandin I2 suppresses the development of gut-brain axis disorder in irritable bowel syndrome in rats

In this study, we attempted to clarify a role of prostaglandin (PG) I2 and its specific receptor, IP in the pathogenesis of irritable bowel syndrome (IBS) using a maternal separation (MS)-induced IBS model. Administration of beraprost (BPS), a specific IP agonist, improved visceral hypersensitivity and depressive state with decreased serum CRF level in the IBS rats. To clarify the mechanism of the effect of BPS, we performed serum metabolome analysis and 1-methylnicotinamide (1-MNA) was identified as a possible candidate for a clue metabolite of pathogenesis of IBS. The serum 1-MNA levels revealed inverse correlation to the level of visceral sensitivity, and positive correlation to a depression marker, immobilizing time. Administration of 1-MNA induced visceral hypersensitivity and depression with increased levels of serum CRF. Since fecal 1-MNA is known for a marker of dysbiosis, we examined the composition of fecal microbiota by T-RFLP analysis. The proportion of clostridium cluster XI, XIVa and XVIII was significantly changed in MS-induced IBS rats treated with BPS. Fecal microbiota transplant of BPS-treated rats improved visceral hypersensitivity and depression in IBS rats. These results suggest for the first time that PGI2-IP signaling plays an important role in IBS phenotypes such as visceral hypersensitivity and depressive state. BPS modified microbiota, thereby inhibition of 1-MNA-CRF pathway, followed by improvement of MS-induced IBS phenotype. These results suggest that the PGI2-IP signaling could be considered to be a therapeutic option for IBS.

Mechanism of Beraprost Effects on Pulmonary Hypertension: Contribution of Cross-Binding to PGE2 Receptor 4 and Modulation of O2 Sensitive Voltage-Gated K+ Channels.

Background: The purpose of this study is to elucidate mechanism(s) by which the orally active PGI2 analog, Beraprost (BPS), ameliorates pulmonary hypertension (PH). Prostaglandins are an important treatment for PH. Mechanisms of their action are not fully elucidated in relation to receptor subtype and effects on O2 sensitive Kv channels.Methods: Distal (3rd order and beyond) pulmonary arteries from chronically hypoxic rats and from humans with established PH were studied. Measurements included pulmonary haemodynamics and histology, vascular reactivity, prostanoid receptor expression and activity of the O2 sensitive Kv channels.Results: Prostacyclin receptor (IP), prostaglandin receptor E3 (EP3) and prostaglandin receptor E4 (EP4) are the main pulmonary artery receptor subtypes in both rat and human pulmonary arteries. Circulating levels of PGI2 and PGE2 were reduced in PH. PH was also associated with reduced receptor expression of IP but not of EP4. The effects on IP expression were overcome with BPS. Dilatory responses in PH to BPS were reduced in the presence of EP4 blockade. Expression and activity of oxygen sensitive Kv channels were reduced in pulmonary artery smooth muscle cell from rats with PH and humans with PAH and were also overcome by administration of BPS. Effects of BPS on oxygen sensitive Kv channels were reduced in the presence of EP4 blockade implicating the EP4 receptor, as well as the IP receptor, in mediating BPS effects.Conclusion: Reduced expression of pulmonary IP receptors and reduced activity of O2 sensitive Kv channels are found in PH in both humans and rats. The orally active prostacyclin analogue, BPS, is able to reverse these changes, partly through binding to the EP4 receptor.

The effectiveness of Beraprost sodium in elderly patients with diabetic peripheral neuropathy and its influence on serum nitric oxide and endothelin-1 levels

Objective To evaluate the effectiveness of Beraprost sodium and its impact on vascular endothelial dysfunction in elderly patients with diabetic peripheral neuropathy (DPN). Methods A total of 86 elderly patients (age≥60 years) with DPN were recruited and randomly assigned into a control group (n=43) and a treatment group (n=43). Both groups received regular treatments including drug treatment such as glucose-lowering, lip-lowering, anti-platelet and neurotropic medications, and non-drug treatment measures such as smoking cessation and foot massage.In addition, the treatment group was given 40 μg oral Beraprost sodium three times a day for 90 days.Data on vibrating perception threshold (VPT), transcutaneous oxygen (tcpO2), ankle-brachial index (ABI), liver and kidney function, hemoglobin A1c (HbA1c), serum nitric oxide (NO) and endothelin-1 (ET-1) were collected before and after treatment. Results No adverse reaction was observed during the experiment.After 90-day treatment, both the control group and the treatment group showed decreased VPT values (F=23.06, 195.13, both P<0.01), increased tcpO2 values (F=304.65, 594.33, both P<0.01), increased ABI (F=119.24, 336.60, both P<0.01), increased serum NO levels (F=375.48, 741.20, both P<0.01), and decreased serum ET-1 levels (F=49.07, 211.24, both P<0.01). Compared with the control group, the value of VPT (F=25.16, P<0.01) and the level of ET-1(F=61.83, P<0.01) were significantly lower, while the level of NO and the values of tcpO2 and ABI were significantly higher (F=24.06, 62.82, 21.46, all P<0.01) in the treatment group. Conclusions Oral beraprost sodium can be effectively and safely used in DNP patients, and it can also alleviate endothelial dysfunction. Key words: Diabetes mellitus; Peripheral neuropathies; Nitric oxide; Beraprost sodium; Endothelin-1

Prostaglandin I2 suppresses the development of diet-induced nonalcoholic steatohepatitis in mice.

Nonalcoholic steatohepatitis (NASH) is a hepatic manifestation of metabolic syndrome. Although the prostaglandin (PG)I2 receptor IP is expressed broadly in the liver, the role of PGI2-IP signaling in the development of NASH remains to be determined. Here, we investigated the role of the PGI2-IP system in the development of steatohepatitis using mice lacking the PGI2 receptor IP [IP-knockout (IP-KO) mice] and beraprost (BPS), a specific IP agonist. IP-KO and wild-type (WT) mice were fed a methionine- and choline-deficient diet (MCDD) for 2, 5, or 10 wk. BPS was administered orally to mice every day during the experimental periods. The effect of BPS on the expression of chemokine and inflammatory cytokines was examined also in cultured Kupffer cells. WT mice fed MCDD developed steatohepatitis at 10 wk. IP-KO mice developed steatohepatitis at 5 wk with augmented histologic derangements accompanied by increased hepatic monocyte chemoattractant protein-1 (MCP-1) and TNF-α concentrations. After 10 wk of MCDD, IP-KO mice had greater hepatic iron deposition with prominent oxidative stress, resulting in hepatocyte damage. In WT mice, BPS improved histologic and biochemical parameters of steatohepatitis, accompanied by reduced hepatic concentration of MCP-1 and TNF-α. Accordingly, BPS suppressed the LPS-stimulated Mcp-1 and Tnf-α mRNA expression in cultured Kupffer cells prepared from WT mice. PGI2-IP signaling plays a crucial role in the development and progression of steatohepatitis by modulating the inflammatory response, leading to augmented oxidative stress. We suggest that the PGI2-IP system is an attractive therapeutic target for treating patients with NASH.-Kumei, S., Yuhki, K.-I., Kojima, F., Kashiwagi, H., Imamichi, Y., Okumura, T., Narumiya, S., Ushikubi, F. Prostaglandin I2 suppresses the development of diet-induced nonalcoholic steatohepatitis in mice.

Intratracheal Administration of Prostacyclin Analogue-incorporated Nanoparticles Ameliorates the Development of Monocrotaline and Sugen-Hypoxia-induced Pulmonary Arterial Hypertension.

:Nanoparticles (NPs) have been used as novel drug delivery systems. Drug-incorporated NPs for local delivery might optimize the efficacy and minimize the side effects of drugs. Intravenous prostacyclin improves long-term survival in patients with pulmonary arterial hypertension (PAH), but it causes serious side effects such as catheter-related infections. We investigated the efficacy and safety of intratracheal administration of a prostacyclin analogue, beraprost (BPS), incorporated NPs in Sugen-hypoxia-normoxia and monocrotaline rat models of PAH and in human PAH pulmonary arterial smooth muscle cells (PASMCs). After a single administration, BPS NPs significantly decreased right ventricular pressure, right ventricular hypertrophy, and pulmonary artery muscularization in the 2 rat models. BPS NPs significantly improved the survival rate in the monocrotaline rat model. No infiltration of inflammatory cells, hemorrhage, or fibrosis was found in the liver, kidney, spleen, and heart after the administration of BPS NPs. No liver or kidney dysfunction was found in the blood examinations. BPS and BPS NPs significantly inhibited the proliferation of human PAH PASMCs after 24 hours of treatment. BPS NPs significantly continued to inhibit the proliferation of human PAH PASMCs at 24 hours after the removal of BPS NPs. BPS NPs significantly induced apoptosis in PAH PASMCs compared to that in non-PAH PASMCs. Intratracheal administration of BPS NPs ameliorates pulmonary hypertension in PAH rat models by a sustained antiproliferative effect and a proapoptotic effect on PAH PASMCs.

The Prostaglandin Agonist Beraprost Aggravates Doxorubicin-mediated Apoptosis by Increasing iNOS Expression in Cardiomyocytes

Doxorubicin (DOX) is widely used as an anti-cancer agent although it causes irreversible cardiomyopathy by increasing oxidative stress and deregulating nitric oxide production. Beraprost (BPS), a stable prostacyclin (PGI2) analog, is a potent vasodilator that has beneficial effects on myocardial ischemia. The objectives of the present study were to delineate the uncertain effects of prostcyclin therapy on DOX induced cardiomyopathy and to explore the mechanisms underlying PGI2 and DOX interaction. For this reason, we stimulated endogenous PGI2 production using bicistronic COX-1/PGIS gene transfer and BPS supplementation, and investigated the effects on DOX-induced cardiomyopathy. Caspase-dependent protein content, lactate dehydrogenase (LDH), DNA fragmentation, and TUNEL positive cells were elevated in DOX-treated cardiomyocytes. These indicators were further elevated by adenovirus-COX- 1/PGIS transfection or BPS supplementation. In addition, PGI2 overexpression further increased iNOS expression and superoxide accumulation in cardiomyocytes compared with DOX alone, which may be the reason for aggravated cytotoxicity. Moreover, BPS can induce cAMP response elements (CRE) binding to the iNOS promoter and phospho- cAMP response element binding protein (CREB) expression in a cyclic AMP-dependent manner. Our in vivo studies show that MnTBAP and aminoguanidine treatment of DOX and BPS co-administered in mice can attenuate caspase-3 and PARP-1 protein expression, and improve mouse survival, as observed in the iNOS gene-deleted mice. In conclusion, we demonstrated that BPS or adv-COX-1/PGIS increases PGI2 levels through iNOS expression and peroxynitrite production, via CREB protein phosphorylation; thereby aggravating DOX-mediated cardiotoxicity.

Application of superior vena cava Doppler spectra in evaluation of the therapeutic effects of hypobaric hypoxia-induced pulmonary hypertension in rats

Objective To explore the value of superior vena cava (SVC) Doppler spectrum in evaluation of the therapeutic effects of intermittent hypobaric hypoxia (HBHO)-induced pulmonary hypertension (PH) in rats and establish a new method for assessing pulmonary hypertension.Methods Fifty male SD rats were included.Forty of them were developed HBHO-PH and randomly divided into four groups with different manipulations:beraprost treatment group,sildenafil treatment group,placebo group and model group,with 10 rats in each group.The rest of 10 rats served as controls.Cardiac structure,pulmonary peak velocity (PAVmax),tricuspid peak velocity (TVEmax) and SVC Doppler ultrasound were performed in all rats before and after treatment for 2 weeks.Pulmonary arterial pressure was determined by the right heart catheterization.The relationship of the parameters with the pulmonary arterial pressure was analyzed.HE staining was done in lung tissues.Results Right heart catheterization showed that pulmonary artery systolic pressure (PASP) of the treatment groups were lower than that of the model group,the difference was significant(P ＜0.01).Pulmonary artery pressure decreased in varying degrees both after placed in a normal environment and after 2 weeks of treatment.PASP of the beraprost treatment group and the sildenafil treatment group decreased significantly and showed no statistical significant difference with the control group.In contrast,PASP of the placebo group was significant higher than that of control group(P ＜ 0.05).No statistically significant difference was found between the non-placebo treatment groups in PASP.Compared with the control group,the right ventricle/body weight ratio of the model group was statistically significant increased in all other groups(P ＜0.01).Right SVC AR/S ratio was well correlated with PASP (r =0.603,P =0.001).Right SVC AR/S ratio was statistically significant lower in treatment groups compared with the model group (P ＜0.01).All groups except the control group demonstrated various degrees of pulmonary arterial wall thickening.Conclusions The right SVC spectrum of AR/S correlates well with PASP and can be used to evaluate the pharmacological therapeutic effect of rats with HBHO-PH,in particular with moderate to severe PH. Key words: Ultrasonography; Vena cava, superior; Hemodynamics; Hypertension, pulmonary; Hypobaric hypoxia

Effects of beraprost sodium (a PGI2 derivative) on chronic hypoxic pulmonary hypertension in the rat

To determine whether beraprost sodium (beraprost) can cause pulmonary vasodilation in chronic hypoxic pulmonary hypertension, we measured the hemodynamic effects of intravenous beraprost, a stable and orally active agent with a PGI2-like structure, in chronic hypoxic (H) and normoxic (N) rats. During anesthesia baseline pulmonary artery pressure (PAP) was 32.0 +/- 1.0 in H rats and 18.0 +/- 0.4 mmHg in N rats. Intravenous beraprost (20 micrograms/kg) elicited acute pulmonary vasodilation by 17.7 +/- 4.6% (5.6 +/- 1.4 mmHg) in H rats and by 16.8 +/- 2.1% (3.0 +/- 0.6 mmHg) in N rats, which indicates that the relative degree of acute pulmonary vasodilation caused by beraprost was similar in H and N rats. Thirty minutes after the drug was injected, PAP had not returned to baseline levels in either H or N rats, and it was lower in H rats (90 +/- 2%) than in N rats (95 +/- 2%). Lungs were isolated and perfused with saline, and those from H rats and N rats showed similar pulmonary vasodilator responses to 2 and 20 micrograms/kg beraprost. These results indicate that although beraprost caused a similar degree of acute pulmonary vasodilation in H and N rats, in H rats the response lasted longer. Thus PGI2 derivatives may be useful as vasodilators in some patients with primary and secondary pulmonary hypertension.

PPARδ-mediated p21/p27 induction via increased CREB-binding protein nuclear translocation in beraprost-induced antiproliferation of murine aortic smooth muscle cells

We previously showed that an increase in the peroxisome proliferator-activated receptor-delta (PPARdelta), together with subsequent induction of inducible nitric oxide synthase (iNOS) by beraprost (BPS), inhibits aortic smooth muscle cell proliferation. Herein, we delineated the mechanisms of the antiproliferative effects of BPS through the induction of p21/p27. BPS concentration dependently induced the p21/p27 promoter- and consensus cAMP-responsive element (CRE)-driven luciferase activities, which were significantly suppressed by blocking PPARdelta activation. Surprisingly, other than altering the CRE-binding protein (CREB), BPS-mediated PPARdelta activation increased nuclear localization of the CREB-binding protein (CBP), a coactivator, which was further confirmed by chromatin immunoprecipitation. Furthermore, novel functional PPAR-responsive elements (PPREs) next to CREs in the rat p21/p27 promoter regions were identified, where PPARdelta interacted with CREB through CBP recruitment. BPS-mediated suppression of restenosis in mice with angioplasty was associated with p21/p27 induction. Herein, we demonstrate for the first time that BPS-mediated PPARdelta activation enhances transcriptional activation of p21/p27 by increasing CBP nuclear translocation, which contributes to the vasoprotective action of BPS.

Evaluation of Drug-drug Interaction Potential of Beraprost Sodium Mediated by P450 In Vitro

Beraprost sodium (BPS), a chemically stable and orally active prostacyclin analogue used for the treatment of chronic occlusive disease and primary pulmonary hypertension, was investigated in terms of its drug-drug interaction mediated by cytochrome P450. In a metabolic enzyme characterization study using P450-expressing insect cell microsomes, beraprost (BP) was slightly metabolized in the presence of CYP2C8, but not metabolized by the other P450 isoforms (CYP1A2, [corrected] CYP2A6, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4, and CYP4A11) at a concentration of 20 microM. These results suggest that none of the P450 isoforms is a major metabolic enzyme of BP. In a P450 induction study using human hepatocytes, BP did not induce any P450 isoform (CYP1A2, CYP2C9, CYP2C19, and CYP3A4) at concentrations of 1-100 microM. Furthermore, in a P450 inhibition study using human liver microsomes, BP did not inhibit any P450 isoform (CYP1A2, CYP2A6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP3A4) at concentrations of 0.05-1 microM. Therefore it is concluded that BP is not involved in drug-drug interaction mediated by P450 isoforms.

Suppression of pseudointimal hyperplasia by a novel prostacyclin analogue: beraprost.

The aim of this study was to evaluate the effect of a novel prostaglandin I2 analogue, beraprost (BPT), on the pseudointimal hyperplasia (PIH) of polytetrafluoroethylene (PTFE) prostheses. A total of 12 rabbits were equally divided into three groups. The control group was given a placebo daily, group 1 was given BPT orally 2 mg/kg per day, and group 2 was given BPT orally 4 mg/kg b.i.d. Exactly 1 cm of the inferior vena cava was resected and replaced by a 3-cm PTFE tube graft. All the grafts were patent when harvested 4 weeks after implantation, but the lumens were narrowed to various extents by PIH. PIH, determined by the dry weight of the intraluminal tissue deposit, was significantly (P < 0.01) suppressed in groups 1 and 2 compared with the control group. High-magnification light microscopy with various staining methods revealed the PIH to be composed mainly of smooth muscle cells (SMCs) and collagen fibrils in all three groups. Transmission electron microscopy revealed that the majority of SMCs in groups 1 and 2 were contractile in form, in contrast with the synthetic form seen in the control group. In conclusion, BPT attenuated the PIH of PTFE grafts by inhibiting the phenotype change in the SMCs.

Clinical evaluation on combined administration of oral prostacyclin analogue beraprost and phosphodiesterase inhibitor cilostazol

Among various oral antiplatelets, a combination of a novel prostacyclin analogue beraprost (BPT) and a potent phosphodiesterase inhibitor cilostazol (CLZ) may result in untoward clinical effects due to possible synergistic elevation of intracellular cAMP (cyclic adenosine 3′,5′-monophosphate). Thereby, a clinical study of the combined administration of the two agents was attempted. Twelve healthy volunteers were assigned to take BPT/CLZ in the following schedule; BPT: 40 μg at day I and 120 μg t.i.d. from day 7 to 14, CLZ: 200 mg t.i.d. from day 3 to 14. At various time intervals, physical examination and blood collection for ex vivo platelet aggregation and determination of intraplatelet cAMP were performed. Throughout the observation period, no significant alteration in vital signs was observed. Seven out of 12 subjects experienced headache of a short duration accompanying facial flush in one and nausea in one, especially after ingestion of CLZ. All of these symptoms, probably caused by the vasodilating effect of the two agents, were of mild degree and no special treatment was required. Intraplatelet cAMP content was gradually but significantly increased to 9.84± 4.59 pmol per 10 9 platelets at day 14 in comparison with the initial value (6.87±2.25 pmol). The platelet aggregability was significantly suppressed at various time intervals but no additive or synergistic inhibitory effect by the combined administration was noted. In conclusion, the combined administration of BPT/CLZ is safe at doses used in the study, though the beneficial clinical effect of the combined administration has yet to be elucidated.