A new method for assessment of an anti-5HT(2A) agent, sarpogrelate hydrochloride, on platelet aggregation

5-HT2A Receptor and 5-HT Degradation Play a Crucial Role in Atherosclerosis by Modulating Macrophage Foam Cell Formation, Vascular Endothelial Cell Inflammation, and Hepatic Steatosis

Aim: Previously, we found that diabetes-related liver dysfunction is due to activation of the 5-HT _2A receptor (5-HT _2A R) and increased synthesis and degradation of 5-HT. Here, we investigated the role of 5-HT in the development of atherosclerosis.

Methods: The study was conducted using high-fat diet-fed male ApoE ^−/− mice, THP-1 cell-derived macrophages, and HUVECs. Protein expression and biochemical indexes were determined by Western blotting and quantitative analysis kit, respectively. The following staining methods were used: oil red O staining (showing atherosclerotic plaques and intracellular lipid droplets), immunohistochemistry (showing the expression of 5-HT _2A R, 5-HT synthase, and CD68 in the aortic wall), and fluorescent probe staining (showing intracellular ROS).

Results: In addition to improving hepatic steatosis, insulin resistance, and dyslipidemia, co-treatment with a 5-HT synthesis inhibitor and a 5-HT _2A R antagonist significantly suppressed the formation of atherosclerotic plaques and macrophage infiltration in the aorta of ApoE ^−/− mice in a synergistic manner. Macrophages and HUVECs exposed to oxLDL or palmitic acid in vitro showed that activated 5-HT _2A R regulated TG synthesis and oxLDL uptake by activating PKCε, resulting in formation of lipid droplets and even foam cells; ROS production was due to the increase of both intracellular 5-HT synthesis and mitochondrial MAO-A-catalyzed 5-HT degradation, which leads to the activation of NF-κB and the release of the inflammatory cytokines TNF-α and IL-1β from macrophages and HUVECs as well as MCP-1 release from HUVECs.

Conclusion: Similar to hepatic steatosis, the pathogenesis of lipid-induced atherosclerosis is associated with activation of intracellular 5-HT _2A R, 5-HT synthesis, and 5-HT degradation.

Serotonin 2A (5-HT2A) receptor affects cell-matrix adhesion and the formation and maintenance of stress fibers in HEK293 cells

5-HT_2A, a G-protein coupled receptor, is widely expressed in the human body, including in the gastrointestinal tract, platelets and the nervous system. It mediates various functions, for e.g. learning, memory, mood regulation, platelet aggregation and vasoconstriction, but its involvement in cell-adhesion remains largely unknown. Here we report a novel role for 5-HT_2A in cell–matrix adhesion.

In HEK293 cells, which are loosely adherent, expression and stimulation of human or rat 5-HT_2A receptor by agonists such as serotonin or 2,5-dimethoxy-4-iodoamphetamine (DOI) led to a significant increase in adhesion, while inhibition of 5-HT_2A by antipsychotics, such as risperidone, olanzapine or chlorpromazine prevented it. 5-HT_2A activation gave rise to stress fibers in these cells and was also required for their maintenance. Mechanistically, the 5-HT_2A-mediated adhesion was mediated by downstream PKC and Rho signaling. Since 5-HT_2A is associated with many disorders such as dementia, depression and schizophrenia, its role in cell–matrix adhesion could have implications for neural circuits.

Management of chronic expanding haematoma using triamcinolone after latissimus dorsi flap harvesting

Chronic expanding haematoma (CEH) is a rare type of haematoma that enlarges slowly and continuously without coagulation. It can occur following surgery because of shear stress-induced bleeding in the scar tissue between the subcutaneous fat and fascia. We present three cases of large chronic CEH that were successfully treated with triamcinolone injections. Three female patients developed large chronic CEH at 9 months, 5 years, and 6 years, respectively, after latissimus dorsi flap harvesting for breast reconstruction. Although the condition did not improve after multiple sessions of haematoma aspiration in the first two patients, it resolved following a single 40-mg triamcinolone injection along with appropriate compression dressing for several weeks. In the third patient, triamcinolone was injected immediately after the initial aspiration of the haematoma, and the condition improved considerably. There were no side effects in any of the patients. To the best of our knowledge, this is the first report of successful treatment of large CEH using triamcinolone. Therefore, we suggest that triamcinolone injections be considered for the treatment of CEH.

Anti-platelet activity of water dispersible curcuminoids in rat platelets

Curcuminoids are active principle of turmeric with plethora of health beneficial properties. In this study, we have evaluated for the first time the effect of water dispersible curcuminoids on rat platelet aggregation. Curcuminoids (10-30 µg/mL) significantly inhibited platelet aggregation induced by agonists viz., collagen, ADP and arachidonic acid. Curcuminoids were found to be two-fold more potent than curcumin in inhibiting platelet aggregation. Intracellular curcuminoid concentration was relatively higher than curcumin in rat platelets. Curcuminoids significantly attenuated thromboxane A2 , serotonin levels in rat platelets which play an important role in platelet aggregation. Curcuminoid treatment increased nitric oxide (NO) levels in platelets treated with agonists. Curcuminoids inhibited free radicals such as superoxide anion released from activated platelets, which ultimately inhibits platelet aggregation. Further, curcuminoids inhibited 12-lipoxygenase activity and formation of 12-hydroperoxyeicosatetraenoic acid (12-HPETE) in activated rat platelets which regulates platelet aggregation. The results suggest that curcuminoids have remarkable anti-platelet activity by modulating multiple mechanisms involved in platelet aggregation. Thus curcuminoids may have a therapeutic potential to prevent platelet activation related disorders.

Prospective study of sarpogrelate hydrochloride on patients with arteriosclerosis obliterans

OBJECTIVE

To evaluate the effect of sarpogrelate for patients with atherosclerotic obliterans (ASO).

PATIENTS AND METHODS

Patients with ASO were randomly divided into sarpogrelate group (n = 92) and control group (n = 84). The patients in sarpogrelate group received sarpogrelate (100 mg, tid), whereas in control group aspirin (100 mg, qd) was administered orally. The patients were followed up monthly to observe any side effect of medication. Clinical manifestation, painless walking distance, Rutherford type and ankle brachial Index (ABI) were studied.

RESULTS

In comparison with control group, the severity of pain, Rutherford type 0 and 1 were improved with statistic significance. Incidence of patients with intermittent claudication decreased from 56.6% before treatment to 28.3% after treatment; the painless walking distance was prolonged (116.3 ± 72.3m vs. 243.5 ± 175.3m, P <0.001); ABI values were increased (0.74 ± 0.17 vs. 0.86 ± 0.18; p <0.001). No side effect of medication was observed.

CONCLUSION

Sarpogrelate has a therapeutic effect on patients with atherosclerotic obliterans.

Comparison of sarpogrelate and ticlopidine in bare metal coronary stent implantation

BACKGROUND

The efficacy and safety of sarpogrelate, a selective 5-hydroxytryptamine receptor subtype 2A antagonist, have not yet been established in bare metal coronary stenting. Accordingly, we sought to clarify whether treatment with sarpogrelate is clinically useful in bare metal coronary stenting.

METHODS

A total of 450 patients who underwent successfully planned or unplanned bare metal coronary stenting were randomly divided into the following 2 groups: the sarpogrelate (300 mg/day) plus aspirin (100 mg/day) group (group S, n=225) and the ticlopidine (200 mg/day) plus aspirin (100 mg/day) group (group T, n=225). Either sarpogrelate or ticlopidine was administered for at least 4 weeks after the procedure. Follow-up coronary arteriography was performed at 6 months after the procedure. The primary endpoints were the incidence of adverse drug reactions requiring a withdrawal of treatment and the rate of binary restenosis. The secondary endpoint was the incidence of stent thrombosis.

RESULTS

The incidence of adverse drug reactions requiring a withdrawal of treatment was significantly lower in group S than in group T (0.44% vs 8%, p=0.002). The rate of binary restenosis did not differ significantly between groups S and T (16.9% vs 18.2%). In addition, the incidence of subacute stent thrombosis did not differ between groups S and T (0.44% vs 0.44%).

CONCLUSIONS

The incidence of adverse drug reactions requiring a withdrawal of treatment was significantly lower with sarpogrelate use than with ticlopidine use. The rate of binary restenosis and the incidence of subacute stent thrombosis did not differ between both drug groups.

HSP27 phosphorylation is correlated with ADP-induced platelet granule secretion

Adenosine diphosphate (ADP) plays a crucial role in hemostasis and thrombosis by activating platelets. ADP has been reported to induce heat-shock protein (HSP) 27 phosphorylation in human platelets. However, the exact role of HSP27 phosphorylation in human platelets has not yet been clarified. In the present study, we investigated the mechanisms and the roles of ADP-induced HSP27 phosphorylation in human platelets. We showed for the first time that both of decreased phosphorylation levels of HSP27 by PD98059, a MEK1/2 inhibitor and SB203580, a p38 MAPK inhibitor were correlated with the suppressed levels of platelet granule secretion but not with platelet aggregation. Furthermore, the inhibition of either the p44/p42 MAPK or p38 MAPK pathways had no effect on ADP-induced platelet aggregation. These results strongly suggest that the ADP-induced phosphorylation of HSP27 via p44/p42 MAPK and/or p38 MAPK is therefore sufficient for platelet granule secretion but not for platelet aggregation in humans.

Effect of Sarpogrelate, a 5-HT2A Antagonist, on Platelet Aggregation in Patients with Ischemic Stroke: Clinical-Pharmacological Dose-Response Study

BACKGROUND AND PURPOSE

It is widely accepted that antiplatelet therapy is effective for secondary prevention of atherosclerotic vascular diseases. We performed a double-blind, controlled clinical-pharmacological study to investigate the antiplatelet efficacy of sarpogrelate, a selective 5-hydroxytryptamine (5-HT(2A)) receptor antagonist, in patients with ischemic stroke, using a new assessment system employing combinations of 5-HT and epinephrine as agonists.

METHODS

Forty-seven patients with ischemic stroke were randomly assigned to three groups: 15 patients received 25 mg sarpogrelate (group L), 16 patients received 50 mg (group M), and 15 patients received 100 mg (group H) orally, three times daily for 7 days. The effect was expressed as maximum intensity of platelet aggregation on the last day of medication. Two combinations of agonists, 0.5 micromol/l 5-HT plus 3 micromol/l epinephrine, and 1 micromol/l 5-HT plus 3 micromol/l epinephrine, were used to induce platelet aggregation.

RESULTS

With both combinations of agonists, sarpogrelate treatment inhibited platelet aggregation dose-dependently (p < 0.025, Jonckheere test). In multiple-group comparison, the effect in group H was greater than that in group L or M (p < 0.025, Wilcoxon rank-sum test).

CONCLUSION

Sarpogrelate treatment inhibited platelet aggregation dose-dependently in patients with ischemic stroke, as judged by a new assessment system employing combinations of 5-HT and epinephrine as agonists.