The effect of a 5HT2 receptor antagonist sarpogrelate (MCI-9042) treatment on platelet function in Buerger's disease

Short-term efficacy of endovascular procedures for lower extremity thromboangiitis obliterans (Buerger's disease)

PURPOSE

Although thrombolysis obliterans (TAO) has been recognized for more than a century, there is no optimal treatment for this disease. The aim of this report was to compare the short-term efficacies of catheter-directed thrombolysis (CDT), percutaneous transluminal angioplasty (PTA) and CDT+PTA in treating TAO disease.

METHOD

Consecutive patients with TAO treated at Ganzhou People's Hospital between 2012 and 2022 were included in this retrospective study. According to the information provided in the medical records, endovascular procedures included CDT, PTA or CDT+PTA. One-year follow-up outcomes of the patients with TAO who underwent endovascular procedures were compared. The primary outcome was major adverse limb event (MALE) and the secondary outcomes were the technical success, complications, ABI at 1 week after surgery and minor amputation.

RESULTS

Sixty-nine patients with TAO were assessed for inclusion in our single-center study from 2012 to 2022 and received endovascular procedures. Among them, 22 patients underwent CDT, 21 patients underwent PTA, and 26 patients underwent PTA+CDT. The one-year follow-up revealed significant differences in the MALE-free survival rates among the three groups, particularly between the CDT group and the PTA+CDT group (the hazard ratio (HR) for MALE-free survival was 0.173, 95% CI [0.050-0.599], p = 0.006). The technical success rates of the three groups were 63.6%, 90.5%, and 92.3%, respectively. There were differences in the ABI at one week after surgery among the three groups.

CONCLUSIONS

Endovascular procedures are effective for TAO in the short term. The effectiveness of CDT alone is suboptimal; combining CDT with PTA achieves the most favorable endovascular treatment outcome; while the effectiveness of PTA falls in between these two procedures.

Effects of aspirin combined with cilostazol on thromboangiitis obliterans in diabetic patients

The present study explored the effects of aspirin combined with cilostazolin in the treatment of diabetic patients with thromboangiitis obliterans and the effects on the related inflammatory factors. A total of 90 diabetic patients with thromboangiitis obliterans admitted to Weifang People's Hospital from August 2015 to June 2017 were selected and divided into the control group (n=45) and the combination group (n=45). Patients in the control group were given aspirin, and those in the combination group were given aspirin combined with cilostazol. Before treatment and 6 weeks after treatment, the clinical data including ankle-brachial index (ABI), 6-min walk test (6MWT) and test data including serum inflammatory factors interleukin (IL)-8, IL-6 and matrix metalloprotease (MMP)-2 and MMP-9 of the two groups were collected for quantitative and statistical analysis. Compared with those in the control group, the ABI and 6MWT in the combination group could be effectively reduced, and the differences were statistically significant (P<0.05). At the same time, cilostazol combined with aspirin could effectively reduce the levels of serum inflammatory factors MMP-2 and MMP-9 in patients, except for nitric oxide (NO), and the differences were statistically significant (P<0.05). Compared with that before treatment, the control and the combination group can significantly improve the clinical symptoms of the patients, and aspirin combined with cilostazol can effectively improve the clinical curative effect of diabetic patients with thromboangitis obliterans and delay the progression of the disease.

A review on thromboangiitis obliterans pathophysiology: thrombosis and angiitis, which is to blame?

A century has passed since thromboangiitis obliterans (TAO), or Buerger's disease, was first described, but the etiology remains unclear. It is still uncertain as to whether thrombosis or vascular inflammation is the first event. TAO is an episodic inflammatory and thrombotic-occlusive vascular disease of unknown origin. The involvement of the distal vessels and nerves within the neuro-vascular bundles occurs almost always in legs and occasionally in arms. The cumulative data demonstrate that at the cellular and molecular levels, at least four main components of inflammatory reactions, including endothelial cells, platelets, leukocytes and sensory neurons, might be involved in TAO pathogenesis. The interactions among these cells in an altered microenvironment of small- and medium-sized vessels may also orchestrate the onset of TAO events. In this review, the factors that may promote thrombosis and angiitis are reconsidered at three levels: (1) host characteristics such as male gender and genetic background; (2) probable triggers including cigarette smoking and infectious agents; and (3) environmental factors such as chronic anxiety and mental stress as a consequence of low socioeconomic status. At each level, the interactions among vascular endothelium, platelets, leukocytes and sensory neurons are discussed.

Pharmacokinetics of a new once-daily controlled-release sarpogrelate hydrochloride compared with immediate-release formulation and the effect of food

WHAT IS KNOWN AND OBJECTIVE

Sarpogrelate is a selective 5-hydroxytryptamine receptor subtype 2A antagonist that inhibits platelet aggregation and vasoconstriction. The aim of this study was to compare the pharmacokinetics of a sarpogrelate controlled-release formulation (CR) with those of the immediate-release formulation (IR). The effect of food on the pharmacokinetics of CR sarpogrelate was also evaluated.

METHODS

A randomized, open-label, 3-period, 3-treatment crossover study was conducted in 50 healthy male subjects. Subjects were allocated into one of six sequence groups. In one period, a 100-mg IR formulation was administered three times at 6-h intervals, and in the other two periods, a 300-mg CR formulation was administered once to fasting and once to fed subjects. Each period was separated by a 7-day washout period. Serial blood samples were collected up to 24 h after the first drug administration in each period. The plasma concentrations of sarpogrelate were analysed by liquid chromatography-tandem mass spectrometry. Pharmacokinetic parameters were calculated by non-compartmental methods.

RESULTS AND DISCUSSION

After the administration of the IR formulation, the plasma concentration reached a peak at 0·48 h and the drug was eliminated with a half-life (t1/2 ) of 0·7 h. After administration of the CR formulation, the plasma concentration reached a peak at 0·5 h and the drug was eliminated with a t1/2 of 3·23 h. The geometric mean ratios (CR/IR) for sarpogrelate area under the plasma concentration-time curve (AUC) and the maximum plasma drug concentration (Cmax) were 1·2040 (90% confidence interval (CI): 1·0992-1·3188) and 0·9462 (90% CI: 0·8504-1·0529). When CR was administered to fed subjects, the time to peak concentration was prolonged to 3·97 h and t1/2 was shortened to 1·45 h. The geometric mean ratios (fasting/fed) for sarpogrelate AUC and Cmax were 0·8573 (90% CI: 0·7687-0·9561) and 0·6452 (90% CI: 0·5671-0·7341).

WHAT IS NEW AND CONCLUSION

After the administration of CR and IR formulations of the same daily dose of sarpogrelate hydrochloride, the overall systemic exposure was slightly higher for the CR than for the IR formulation, whereas peak concentration was comparable between the two formulations. Food reduced the bioavailability of sarpogrelate CR.

Chronic treatment of hydroxytryptamine type 2a receptor antagonist sarpogrelate hydrochloride modulates the vasoreactivity of serotonin in experimental rabbit vein grafts

OBJECTIVE

It has been suggested that 5-hydroxytryptamine (5-HT) plays a role in the pathogenesis of vein graft spasms. It is suggested that smooth muscle 5-HT(2A) and 5-HT(1B) receptors contribute to 5-HT-induced contraction, while endothelial 5-HT(1B) receptors contribute to the 5-HT-induced endothelium-mediated relaxation. We recently found that chronic administration of the selective 5-HT(2A) receptor antagonist sarpogrelate hydrochloride (SH) enhances the function of endothelium-derived nitric oxide (NO) in rabbit vein grafts. However, it is unknown if such treatment modulates 5-HT-induced vasospasm in vein grafts, and if so, what the underlying mechanisms are.

METHODS

Male rabbits were divided into two groups: a control group and an SH-treated group. The jugular vein was interposed in the carotid artery in reversed fashion. Isometric tension was examined using vein grafts after 4 weeks. 5-HT (10(-8) -10(-6) M)-induced contraction was obtained in each group in the absence or presence of the NO synthase inhibitor l-N(G)-nitroarginine (L-NNA). The expression of 5-HT(2A) and 5-HT(1B) receptors was examined immunohistochemically.

RESULTS

The 5-HT induced a concentration-dependent contractions in both groups. L-NNA did not significantly modify the 5-HT-induced contraction in the control group but enhanced it in the SH group. The 5-HT(1B) receptor antagonist GR55562 inhibited the 5-HT-induced contraction in the control group, while it increased the sensitivity of contraction to 5-HT in the SH-treated group in the absence (but not in the presence) of L-NNA. Positive immunoreactivities against 5-HT(1B) and 5-HT(2A) receptors were identified in endothelial and medial regions of vein grafts in both groups, and the expression of 5-HT(2A) receptors (but not 5-HT(1B) receptors) was significantly less in the SH-treated group than in the control group.

CONCLUSION

Chronically administered SH to rabbits upregulates the autoinhibitory mechanism by 5-HT through a release of NO from endothelium via an activation of endothelial 5-HT(1B) receptors, thus attenuating its own contraction in vein grafts. Furthermore, such SH treatment downregulates the expression of smooth muscle 5-HT(2A) receptors, thus further attenuating the 5-HT-induced contraction. These novel findings further support the clinical usefulness of SH in vein graft spasm after bypass grafting.

Thromboangiitis obliterans (Buerger's disease): searching for a therapeutic strategy

Treatment of thromboangiitis obliterans (Buerger's disease) includes both surgical and nonsurgical approaches, or a combination of both. A definite therapeutic approach has not yet been set. This article reviews the proposed therapeutic strategies and considers the advantages and disadvantages of each treatment. Cessation of smoking seems to be the only globally accepted therapeutic measure to prevent disease progression. A number of promising novel therapeutic strategies may prove useful for the treatment of this physically and socially mutilating disease.

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.

5-HT2A receptor antagonist increases circulating adiponectin in patients with type 2 diabetes

We compared the levels of plasma adiponectin, platelet activation markers (P-selectin, CD63, PAC-1, annexin V, and platelet-derived microparticles), and endothelial injury markers (soluble E-selectin and soluble vascular cell adhesion molecule-1) in 53 patients with type 2 diabetes mellitus to investigate potential contributions to diabetic vascular complications. In addition, we administered serotonin antagonist (sarpogrelate hydrochloride) to type 2 diabetes patients who had increased soluble E-selectin levels. The concentrations of platelet activation markers and endothelial injury markers in diabetic patients were significantly higher than those in normal subjects. However, levels of adiponectin were lower in type 2 diabetes patients than in control subjects. A total of 32 patients had high-soluble E-selectin levels (soluble E-selectin >or= 62 ng/ml); a subset of patients that also had significant elevation of platelet activation and endothelial injury markers compared with patients without high soluble E-selectin. In addition, both platelet-P-selectin and platelet-derived microparticle levels negatively correlated with the adiponectin level. Patients with high soluble E-selectin exhibited significant improvement of all markers after sarpogrelate hydrochloride treatment. These findings suggest that there is a link between vascular change in type 2 diabetes and activated platelets, endothelial dysfunction, and an adiponectin abnormality.

New treatment of lumbar disc herniation involving 5-hydroxytryptamine2A receptor inhibitor: a randomized controlled trial

OBJECT

Serotonin or 5-hydroxytryptamine (5-HT) is a chemical mediator associated with nucleus pulposus-induced radiculopathy. Inhibition of 5-HT receptors may potentially alleviate symptoms in patients with lumbar disc herniation. This prospective randomized controlled study was performed to evaluate the efficacy of the 5-HT2A receptor inhibitor in the treatment of symptomatic lumbar disc herniation.

METHODS

Forty patients with sciatica due to L4-5 or L5-S1 disc herniation were randomly allocated to treatment with the 5-HT2A inhibitor (sarpogrelate 300 mg/day) or nonsteroidal antiinflammatory drugs (NSAIDs; diclofenac 75 mg/day). Low-back pain, leg pain, and numbness were evaluated using a visual analog scale (VAS) before and after a 2-week course of treatment. The patients received only allocated medicine during the 2-week regimen and were thereafter allowed to choose any treatment options depending on their residual symptoms. One-year clinical outcomes were assessed based on the rates of additional medical interventions. The mean VAS score improvements in the 5-HT2A and NSAID groups were 33 and 46% for low-back pain, 32 and 32% for leg pain, and 35 and 22% for leg numbness, respectively. After the 2-week regimen, no additional medical interventions were required in 50% of 5-HT2A-treated patients and 15% of those receiving NSAIDs. Epidural or nerve root block procedures were performed in 35% of the 5-HT2A group and 45% of the NSAID group. Surgery was required in 20% of the 5-HT2A group and 30% of the NSAID group patients.

CONCLUSIONS

The current study provided evidence that the efficacy of the 5-HT2A inhibitor was comparable with that of NSAID therapy for lumbar disc herniation. The 5-HT2A inhibitor has the potential to alleviate symptoms in patients with lumbar disc herniation.

The ratio of plasma to whole-blood serotonin may be a novel marker of atherosclerotic cardiovascular disease

Because atherosclerotic vascular lesions stimulate platelets, the platelets release serotonin (5-hydroxytryptamine, aka 5-HT). We therefore measured 5-HT concentrations not only in platelet-poor plasma but also in whole blood as a means of assessing vascular lesions. The plasma concentration of 5-HT tended to increase with age, whereas that in whole blood decreases. Therefore the ratio of the plasma to the whole-blood concentration of 5-HT (P/WB) increases with age. This may be a result of the activation of platelets in older subjects with atherosclerotic vascular damage. Patients who underwent coronary angiography (CAG) were classified into 4 groups according to diagnosis: effort-induced angina pectoris (eAP), old myocardial infarction (OMI), vasospastic angina pectoris (VSAP), and unstable angina (uAP). The mean plasma 5-HT concentration was significantly (P <.01) greater in patients with eAP, uAP, OMI, and VSAP than in healthy controls, whereas the concentration in whole blood was lower in patients with eAP than in healthy controls. When the P/WB ratios were calculated, the mean levels in all disease groups were significantly higher than that in the healthy controls. These findings suggested that 5-HT is released into the plasma from the platelets and that the concentration in the platelets decreases in patients with atherosclerosis.

Effects of R-102444, an orally active 5-HT2A receptor antagonist, in rat models of peripheral vascular disease

R-102444 is a prodrug that is metabolized into R-96544, a potent and selective 5-hydroxytryptamine2A (5-HT2A) receptor antagonist. The effects of R-102444 on peripheral vascular disease were examined using two different rat models: one induced by lauric acid and the other by ergotamine plus epinephrine. R-96544 (0.3-30 nM) relaxed the 5-HT (3 microM)-precontracted rat caudal artery in a concentration-dependent manner. The intravenous administration of R-96544 (0.3-3 microg/kg) to anesthetized rats inhibited the pressor response to 5-HT (50 microg/kg i.v.) dose dependently. The oral administration of R-102444 (1 mg/kg) to rats resulted in a marked inhibition of platelet aggregation induced by 5-HT plus ADP, and statistically significant inhibition was still evident 8 h after the dosing. In contrast, sarpogrelate, at a dose of 100 mg/kg p.o., produced only a moderate antiplatelet effect. Oral administration of R-102444 (1 mg/kg/day, o.d.) significantly prevented the progression of peripheral vascular lesion induced by the injection of lauric acid into a rat femoral artery, whereas sarpogrelate (100 mg/kg/day) showed only a minimal effect. Both 5-day treatments with R-102444 (1-30 mg/kg/day p.o., o.d.), one commenced 1 h before the injection of epinephrine plus ergotamine and one just after injection, resulted in the prevention of rat tail gangrene in a dose-dependent manner, whereas sarpogrelate (100 mg/kg) produced a minimal protection in this model. Based on these results, we conclude that 5-HT2A receptor activation is involved in peripheral vascular disease in the rat and that R-102444 is a useful oral agent for the investigation of diseases involving 5-HT2A receptor activation.

Enhanced platelet force development despite drug-induced inhibition of platelet aggregation in patients with thromboangiitis obliterans--two case reports

Thromboangiitis obliterans (TAO) is a nonatherosclerotic, nonnecrotizing, nonspecific, segmental inflammatory obliterative vasculitis, characterized by decreased flow to the distal extremities and increased risk of amputation. While smoking cessation is viewed as critical to successful treatment, various therapeutic options have been employed. While many treatment regimens seek to diminish platelet function, there are relatively few studies of platelet function in this disease entity and even fewer that have offered evidence of increased platelet activity. The authors report here 2 cases of TAO in which evaluations for hypercoagulable states and of platelet function were performed. Platelet contractile force (PCF) was found to be 82% higher than a normal control in 1 TAO patient and 340% higher than normal in the second patient. This was true despite the fact that platelet aggregations confirmed suppression of aggregation by antiplatelet medications. Elevated PCF has been seen in a variety of conditions, such as coronary artery disease and diabetes mellitus, in which endothelial function is abnormal. Whether high PCF values play a role in the pathogenesis of these diseases or simply serve as markers of enhanced platelet function and/or endothelial dysfunction awaits additional evaluations.

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.

Effects of sarpogrelate hydrochloride on adenosine diphosphate- or collagen-induced platelet responses in arteriosclerosis obliterans

To evaluate the effects of the 5-HT2 receptor antagonist sarpogrelate hydrochloride (sarpogrelate) on platelet responses in arteriosclerosis obliterans (ASO), we examined platelet aggregation and its relationships to platelet-derived growth factor (PDGF), soluble P-selectin (sP-selectin), and transforming growth factor-beta 1 (TGF-beta1). Circulating plasma levels of PDGF and sP-selectin in 13 patients with ASO after 1 week of medication with sarpogrelate were significantly lower than those before medication. In contrast, circulating plasma levels of TGF-beta1 after medication were significantly higher than those before medication. When platelet-rich plasma obtained from ASO patients after medication was stimulated with adenosine diphosphate (ADP) or collagen, platelet aggregation was suppressed compared with rates before medication. Significant decreases in levels of PDGF, sP-selectin and TGF-beta1 released from platelets in response to 5 micromol/l ADP and 1 microg/ml collagen after taking of sarpogrelate were found. There were close correlations between platelet aggregation and respective molecules released from platelets. In conclusion, since platelet activation is involved in pathogenesis of thrombotic disease, sarpogrelate may suppress the development of obstructive arteriosclerosis. PDGF and TGF-beta1, as well as sP-selectin, appear to be useful markers for clinical evaluation of anti-platelet drugs.

The swirling phenomenon in stored platelets is influenced by their endogenous serotonin

The presence of the swirling phenomenon is useful to define platelet concentrates that are suitable for transfusion. If it is possible to identify donor-related factors which are related to persisting swirling during storage, it is possible to select platelet donors. Endogenous platelet serotonin content is stable and easily measured and related to agonist-induced serotonin secretion. During a 3-month period, the swirling in 825 single donor platelet concentrates was controlled before issue. Endogenous serotonin, % serotonin release and swirling were tested in 21 concentrates with poor or no swirling during storage. Sixty-three concentrates were randomly selected from the routinely prepared platelet concentrates and were routinely tested with the same analyses on days 1 and 7. To evaluate an obvious effect of endogenous serotonin on the swirling phenomenon, eight platelet concentrates prepared from buffy coat, each from four donors, were divided. One part was stored in the presence of 8.5 micromol serotonin L-1, and analysed as the control concentrates. The endogenous serotonin content in the 'low- swirling' concentrates was significantly lower than in the control group (P < 0.001). PCO2 and pH were significantly lower, and PO2 and MPV significantly higher than in the controls. In the control group, swirling after 7 days was significantly correlated with serotonin release. In the eight buffy-coat concentrates enriched in endogenous serotonin, both swirling and the percentage serotonin release were improved after storage for 10 days, compared with nonenriched concentrates. This study suggests that endogenous serotonin content and serotonin release are factors that may be of significance concerning preservation of the swirling phenomenon in platelet concentrates during storage.