Effects of sarpogrelate on blood viscosity

The objective of the present study was to evaluate the effects and safety of sarpogrelate hydrochloride (sarpogrelate) in patients with elevated blood viscosity (BV), after 12 and 24 weeks of twice (BID) or thrice (TID) daily administrations of sarpogrelate (100 mg). The participants received oral sarpogrelate administration for 24 weeks and visited the hospital every 12 ± 2 week for blood viscosity measurements at shear rates of 5 and 300 s^-1. The BV measured at shear rate of 5 s^-1 in male patients decreased significantly from 18.91 cP at the baseline to 16.3 cP after 24 weeks of sarpogrelate administration (13.6 % drop, p < 0.001). The BV measured at 5 s^-1 in female decreased more significantly from 17.5 cP at the baseline to 13.4 cP after 24 weeks of sarpogrelate administration (23.0 % drop, p < 0.001). In summary, sarpogrelate may be considered as a possible therapeutic option for improving BV in patients with elevated blood viscosity. In particular, the reduction of the low-shear BV with the help of a viscosity-reducing drug such as sarpogrelate may be considered as a potentially new pharmacological tool for microvascular disease.

Effect of food on the pharmacokinetic properties of the oral sarpogrelate hydrochloride controlled-release tablet in healthy male Korean subjects

BACKGROUND

A new controlled-release formulation of sarpogrelate, a 5-hydroxytryptamine receptor subtype 2 antagonist that blocks serotonin-induced platelet aggregation, has been developed for once-daily administration.

OBJECTIVE

This study evaluated the effect of food on the pharmacokinetic properties of controlled-release sarpogrelate (sarpogrelate CR) in healthy volunteers.

METHODS

A randomized, open-label, two-period, two-treatment crossover study was performed in healthy male Korean subjects. Following an overnight fast, a single dose of sarpogrelate CR 300 mg was administered either in the fasted condition or immediately after a high-fat breakfast. Pharmacokinetic parameters were calculated using a noncompartmental analysis. Tolerability was determined using clinical laboratory testing and physical examination, including vital sign measurements, electrocardiography, and interviews with the volunteers regarding adverse events (AEs).

RESULTS

A total of 24 healthy subjects were enrolled, 23 of whom completed the study (mean [range] age, 26 years [21-45]; weight, 68.1 kg [56.0-79.9]; body mass index, 22.1 kg/m(2) [18.8-25.0]). Sarpogrelate C(max) and AUC(last) were decreased In the fed condition compared with those in the fasted condition, with geometric mean ratios (90% CI) of 0.4868 (0.4041-0.5864) and 0.7394 (0.6809-0.8028), respectively. T(max) was delayed from 0.75 to 4.0 hours after a high-fat meal, but the fed condition exhibited a similar elimination profile to that of the fasted condition. The most commonly reported AE was headache (n = 2), and other AEs were reported in 1 subject each. All of the AEs were considered mild in intensity, and the participants recovered without treatment.

CONCLUSIONS

Compared with the administration of sarpogrelate CR 300 mg in the fasted condition, administration with food was associated with a decreased rate and extent of absorption, as assessed by C(max) and AUC(last), respectively. The drug was well-tolerated by the healthy subjects in this study.

Glucuronidation of a sarpogrelate active metabolite is mediated by UDP-glucuronosyltransferases 1A4, 1A9, and 2B4

Sarpogrelate is a selective serotonin 5-HT2A-receptor antagonist used to treat patients with peripheral arterial disease. This drug is rapidly hydrolyzed to its main metabolite (R,S)-1-[2-[2-(3-methoxyphenyl)ethyl]phenoxy]-3-(dimethylamino)-2-propanol (M-1), which is mainly excreted as a glucuronide conjugate. Sarpogrelate was also directly glucuronidated to an O-acyl glucuronide and a N-glucuronide by UDP-glucuronosyltransferases (UGTs) in human liver microsomes (HLMs). Since M-1 is pharmacologically more active than sarpogrelate, we examined glucuronidation of this metabolite in HLMs and characterized the UGTs responsible for M-1 glucuronidation. Diastereomers of O-glucuronide (SMG1 and SMG3) and a N-glucuronide (SMG2) were identified by incubation of M-1 with HLMs in the presence of uridine 5'-diphosphoglucuronic acid (UDPGA), and their structures were confirmed by nuclear magnetic resonance and mass spectrometry analyses. Two O-glucuronides were identified as chiral isomers: SMG1 as R-isomer and SMG3 as S-isomer. Using recombinant UGT enzymes, we determined that SMG1 and SMG3 were predominantly catalyzed by UGT1A9 and UGT2B4, respectively, whereas SMG2 was generated by UGT1A4. In addition, significant correlations were noted between the SMG1 formation rate and propofol glucuronidation (a marker reaction of UGT1A9; r = 0.6269, P < 0.0031), and between the SMG2 formation rate and trifluoperazine glucuronidation (a marker reaction of UGT1A4; r = 0.6623, P < 0.0015) in a panel of HLMs. Inhibition of SMG1, SMG2, and SMG3 formation by niflumic acid, hecogenin, and fluconazole further substantiated the involvement of UGT1A9, UGT1A4, and UGT2B4, respectively. These findings collectively indicate that UGT1A4, UGT1A9, and UGT2B4 are the major UGT isoforms responsible for glucuronidation of M-1, an active metabolite of sarpogrelate.

Therapeutic Potentials of Sarpogrelate in Cardiovascular Disease*

In view of the pivotal role of serotonin (5-HT) in a wide variety of cardiovascular disorders, extensive effort has been made to develop different types of 5-HT receptor antagonists for therapeutic use. On the basis of experimental studies, this article is focused on the potentials of sarpogrelate, a specific 5-HT2A receptor antagonist as an antiplatelet, antithrombotic, antiatherosclerotic and antianginal agent. The major effects of sarpogrelate are due to the inhibition of 5-HT-induced platelet aggregation and smooth muscle cell proliferation. This agent was found to attenuate the 5-HT-mediated increase in intracellular Ca2+ and ischemia-reperfusion injury in the heart. Sarpogrelate has been found to have beneficial effects in peripheral vascular disease, restenosis after coronary stenting, pulmonary hypertension, acute and chronic myocardial infarction.

The 5-hydroxytryptamine2A receptor antagonist sarpogrelate hydrochloride inhibits acute platelet aggregation in injured endothelium

In this study, the effect of sarpogrelate hydrochloride, a 5-hydroxytryptamine2A receptor antagonist, on platelet aggregation at the site of injured carotid artery endothelium was examined. The rat common carotid artery was clamped for 30 min to induce endothelial injury. Sarpogrelate hydrochloride was administered before and after the injury, and the effects were compared with those in rats receiving sham operation only and those receiving clipping injury but no sarpogrelate hydrochloride. The animals were killed 24 h after the procedure. The common carotid artery was examined by scanning electron microscopy and stained immunochemically for factor VIII. Sarpogrelate hydrochloride treatment was associated with reduced aggregation of platelets on electron microscopy and lower expression of factor VIII at the injured intima. Sarpogrelate hydrochloride has an inhibitory effect on platelet aggregation at the intima in the acute stage after injury, suggesting that this drug may be used to prevent early ischaemic complications after surgical or endovascular arterial intervention.

Effectiveness of a novel serotonin blocker, sarpogrelate, for patients with angina pectoris

BACKGROUND

We have recently demonstrated that a single oral administration of sarpogrelate, a 5-HT(2A) receptor antagonist, may improve exercise capacity in anginal patients with well-developed collaterals. The aim of the current study was to investigate the effectiveness of 2-week treatment with sarpogrelate on anginal symptoms and exercise capacity in anginal patients.

METHODS

A treadmill exercise test was repeated after a 2-week period with or without sarpogrelate (100 mg 3 times a day) in 20 patients with angiographically proven stable angina. Anginal symptoms and daily physical activity by the specific activity scale (SAS) were also evaluated.

RESULTS

Treatment with sarpogrelate significantly increased the SAS score and prolonged exercise time to the onset of 0.1-mV ST depression. When data were analyzed in a subgroup of patients (n = 8) with well-developed collaterals, the treatment with sarpogrelate decreased the number of anginal attacks (control vs sarpogrelate, 3.0 +/- 2.8 vs 0.9 +/- 1.1/2 weeks, P <.05), increased the SAS score (5.2 +/- 1.6 vs 6.2 +/- 1.3 METS, P <.05), and increased the time to the onset of 0.1-mV ST depression (235 +/- 84 vs 295 +/- 127 seconds, P <.05). In addition, the double product at the onset of 0.1-mV ST depression increased by 15% (P <.05) after sarpogrelate. In contrast, all parameters were not significantly changed after sarpogrelate treatment in patients (n = 12) without well-developed collaterals.

CONCLUSIONS

These findings indicate the therapeutic effectiveness of sarpogrelate for anginal patients, especially for patients with well-developed collaterals.

Enhancement by cyclosporine A and tacrolimus of serotonin-induced formation of small platelet aggregation

Cyclosporine A (CsA) may increase the incidence of thrombotic events, but whether tacrolimus (Tc) has such effects is still unclear. The serotonergic system has been linked to the thrombotic effects of CsA, but a direct effect of CsA on serotonin-induced platelet aggregation has not been demonstrated because of methodological difficulties. We measured the effects of CsA and Tc on serotonin-induced platelet aggregate formation by particle counting using light scattering. CsA and Tc both enhanced serotonin-induced formation of small platelet aggregates, however, neither CsA nor Tc affected aggregation induced by high or low concentrations of ADP, with or without addition of a serotonin receptor antagonist. Both CsA and Tc enhance platelet aggregation induced via the serotonin pathway.

Blockade of 5-HT(2A) receptors by sarpogrelate protects the heart against myocardial infarction in rats

BACKGROUND

It has been shown that serotonin (5-hydroxytryptamine, 5-HT) is involved in exacerbating vascular abnormalities; however, its role in mediating changes in cardiac function due to myocardial injury has yet to be established. This study examined the effect of sarpogrelate, a 5-HT(2A) receptor blocker, in preventing cardiac dysfunction due to myocardial infarction (MI).

METHODS AND RESULTS

Rats were treated 3 days before surgery with or without 5 mg x kg(-1) x day(-1) sarpogrelate, and the left coronary artery was ligated for 3 weeks to induce MI. Sarpogrelate reduced the mortality from 40% to 30%, infarct size from 35% to 25%, and left ventricular end diastolic pressure from 15 mm Hg to 10 mm Hg in MI rats. Electrocardiographic (ECG) tracings showed a marked deviation in the ST-segment and prolongation of the QTc interval in MI rats during the 3 weeks; these changes were attenuated by sarpogrelate pretreatment. In another set of experiments, MI rats were treated with 5 mg x kg(-1) x day(-1) sarpogrelate 1 hour after the surgery, and the hemodynamic and electrocardiograph changes were assessed at 3 weeks. This posttreatment was also found to reduce infarct size, improve cardiac function, and attenuate ECG changes.

CONCLUSIONS

Sarpogrelate attenuates cardiac dysfunction, infarct size, and changes in the ECG due to MI. These results also support the view that serotonin and 5-HT(2A) may contribute to the deleterious effects of ischemic injury in the heart.

Sarpogrelate diminishes changes in energy stores and ultrastructure of the ischemic-reperfused rat heart

Although the involvement of serotonin in exacerbating vascular abnormalities in ischemic heart disease has been established, its role in mediating changes in cardiac function due to ischemia reperfusion (IR) is poorly understood. The aim of this study was to investigate the effect of a serotonin blocker, sarpogrelate (5-HT2A antagonist), in preventing cardiac injury due to IR. Isolated rat hearts were subjected to 30 min of global ischemia followed by 1 h of reperfusion. Sarpogrelate (50 nM-0.9 µM) was infused 10 min before ischemia as well as during the reperfusion period. The IR-induced changes in left ventricular developed pressure, left ventricular end diastolic pressure, rate of pressure development, and rate of pressure decay were attenuated (P < 0.05) with sarpogrelate treatment. Sarpogrelate also decreased the ultrastructural damage and improved the high energy phosphate level in the IR hearts (P < 0.05). This study provides evidence for the attenuation of IR-induced cardiac injury by 5-HT2A receptor blockade and supports the view that serotonin may contribute to the deleterious effects of IR in the heart.Key words: ischemia reperfusion, sarpogrelate, serotonin receptor blockade.

Effect of sarpogrelate hydrochloride on platelet-derived microparticles and various soluble adhesion molecules in diabetes mellitus

We measured platelet-derived microparticles, activated platelets, and various adhesion molecules in 48 patients with diabetes mellitus. We also performed a comparative study of these parameters before and after administration of sarpogrelate hydrochloride. The numbers of platelet-derived microparticles and activated platelets were increased significantly in diabetic patients, and CD63-positive platelets were increased in patients with diabetic complications and poorly controlled blood glucose. Soluble adhesion molecules and thrombomodulin were also increased significantly. After administration of sarpogrelate hydrochloride, not only CD62p- and CD63-positive platelets, but also platelet-derived microparticles were decreased significantly. Soluble adhesion molecules and thrombomodulin were also significantly decreased after the treatment. These data suggest that (a) in patients with diabetes, antiplatelet therapy with sarpogrelate hydrochloride is a useful antithrombin therapy because it suppresses the production of intrinsic coagulants by activated platelets; and (b) sarpogrelate hydrochloride decreases endothelial cell damage via adhesion molecules.

Sarpogrelate, a selective 5-HT2A serotonergic receptor antagonist, inhibits serotonin-induced coronary artery spasm in a porcine model

Serotonin is one of the most important vasoactive substances and has been implicated in the pathogenesis of coronary artery spasm and of acute coronary syndrome. We have recently demonstrated that local and long-term treatment with interleukin-1beta(IL-1beta) causes coronary arteriosclerotic changes and hyperconstrictive responses to serotonin in pigs in vivo. However, it remains to be examined which serotonergic (5-HT) receptor subtype mediates coronary spasm and whether alterations in serotonergic receptors are involved in the abnormality. In this study, we examined the inhibitory effect of sarpogrelate, a selective 5-HT2A serotonergic receptor antagonist, on the serotonin-induced coronary spasm as well as the possible alterations of serotonergic receptors in our porcine model. A segment of the porcine coronary artery was carefully dissected and aseptically wrapped with cotton mesh absorbing IL-1beta-bound microbeads from the adventitia. Two weeks after the procedure, angiographic study was performed, followed by binding assay for 5-HT1B and 5-HT2A serotonergic receptors and reverse transcription-polymerase chain reaction (RT-PCR) analysis for mRNA of those receptors. Angiographic study showed coronary vasospastic responses to serotonin at the IL-1beta-treated site. Sarpogrelate dose-dependently inhibited the serotonin-induced coronary spasm, but it did not affect the prostaglandin F2alpha-induced vasoconstriction. Radiolabeled receptor-binding assay showed that receptor affinity or receptor number of the 5-HT1B, or 5-HT2A receptors did not differ significantly between the spastic and the control sites. Furthermore, RT-PCR analysis showed that the expression of neither 5-HT2A nor 5-HT1B receptor mRNA was significantly altered at the spastic site. These results indicate that serotonin-induced coronary spasm is mediated primarily by 5-HT2A receptor in our porcine model, although the 5-HT2A receptor was not up-regulated, suggesting that alteration in the signal-transduction pathway for vascular smooth muscle contraction beyond the 5-HT2A receptor plays a primary role in the pathogenesis of coronary spasm in our porcine model.