ULTIMATE-SHF trial (UdenafiL Therapy to Improve symptoMAtology, exercise Tolerance and hEmodynamics in patients with chronic systolic heart failure): study protocol for a randomized, placebo-controlled, double-blind trial

Background

Over the last few years, the use of phosphodiesterase type 5 (PDE5) inhibitors has been expanded to management of various cardiovascular disorders beyond pulmonary arterial hypertension. This study is designed to investigate the ability of udenafil, a newly developed long-acting PDE5 inhibitor, to improve functional capacity and hemodynamic status in a cohort of chronic systolic heart failure (SHF) patients.

Methods/design

Stable, chronic SHF patients will be randomly assigned to placebo (26 patients) or udenafil at a dose of 50 mg twice per day (26 patients) for the first 4 weeks followed by 100 mg twice daily for the next 8 weeks. Eligibility criteria will be age ≥18 years, clinical diagnosis of chronic SHF with current New York Heart Association class II to IV symptoms, left ventricular ejection fraction ≤ 40%, and experience of at least one of following during the 12 months prior to study entry: hospitalization for decompensated heart failure, acute treatment with intravenous loop diuretics or hemofiltration, or pulmonary artery systolic pressure ≥40mmHg on transthoracic echocardiography. Pharmacological therapy for SHF will be optimized in all patients at least 30 days before study entry. The primary outcome will be the change of maximal oxygen uptake, assessed by cardiopulmonary exercise testing. Secondary outcomes will include changes in ventilatory efficiency (minute ventilation/carbon dioxide production slope), left ventricular systolic and diastolic parameters, pulmonary artery systolic pressure, plasma concentration of brain natriuretic peptide, occurrence of mortality or hospitalization for heart failure, and the occurrence of any adverse event.

Clinical trial registration

Unique identifier: NCT01646515

Under-utilization of donor hearts in the initial era of the heart transplant program in Korea- review of 13 years’ experience from the Korea national registry

BACKGROUND

Heart transplantation (HTPL) is the effective treatment option to improve quality of life as well as survival of terminal heart failure patients. Shortage of donors, however, limits HTPL to all indicated cases. The temporal trend and clinical characteristics of HTPL donors in Korea were therefore investigated.

METHODS AND RESULTS

Among 2,001 brain-death donors registered in Korean Network for Organ Sharing from February 2000 to May 2012, a total of 28% of hearts (n=552) were utilized for HTPL. The mean age of Korean heart donors was 10 years younger than that of heart recipients (33.2 ± 12 years vs. 43.2 ± 17 years, respectively). The oldest was 56 years old, and donors aged over 50 accounted for only 6.2% (n=34) of total cases. Female donors were utilized less than male donors (23.6% vs. 29.6%, respectively). To determine characteristics of declined donor heart candidates, subgroup analysis of echocardiographic data was done, and 74.6% had normal ventricular function and structure, although only 42.3% were actually transplanted. The utilization rate of donor hearts with minor echocardiography abnormalities was only 15.2%. Clinical outcomes of marginal heart donors were not different from non-marginal donors.

CONCLUSIONS

Although shortage of donor organs is an emerging issue, most donor hearts have been under-utilized in the past in Korea. In particular, aged and female donor hearts with minor echocardiographic abnormalities had a low rate of utilization.

Heart transplantation in the elderly patients: midterm results

Background

Heart transplantation in elderly patients has raised concerns because of co-morbidities and limited life expectancy in the era of donor shortage. We examined the outcomes after heart transplantation in elderly patients.

Materials and Methods

From March 1994 to December 2011, 81 patients (male:female=64:17, 49.1±14.0 years) underwent heart transplantation. The outcomes after heart transplantation in the younger patients (<60 years; group Y, n=60) were compared with those in the elderly patients (≥60 years; group O, n=21). The follow-up duration was 51.8±62.7 months.

Results

Early mortality (≤30 days) occurred in 5.0% (3/60) and 4.8% (1/21) of groups Y and O, respectively (p>0.999). There were no differences in overall survival between the two groups (p=0.201). Freedom from rejection was higher in group O than in group Y (p=0.026). Multivariable analysis revealed that age ≥60 years was not a significant risk factor for long-term survival; postoperative renal failure was the only significant risk factor for long-term survival (p=0.011).

Conclusion

Early and mid-term results of heart transplantation in elderly patients were similar to those in younger patients.

Serum alkaline phosphatase is a predictor of mortality, myocardial infarction, or stent thrombosis after implantation of coronary drug-eluting stent

AIMS

The association between alkaline phosphatase (ALP) and mortality was reported in several subgroups of patients. But, the role of ALP in overall coronary artery disease (CAD) patients after percutaneous coronary intervention (PCI) remains unknown. The aim of this study was to examine the prognostic value of the ALP level in patients with CAD who underwent PCI with drug-eluting stent (DES).

METHODS AND RESULTS

We prospectively included CAD patients who underwent PCI with DES. After exclusion of patients with liver disease and cancer, 1636 patients were selected for the analysis of clinical outcomes (median duration of follow-up; 762 days, inter-quartile range; 494-1068 days), and were classified into tertiles by baseline measurements of ALP (<63, 63-78, and >78 IU/L). After adjustment of potential confounders including angiographic data, the independent and dose-dependent association was observed between tertile of ALP and the adjusted hazard ratio (HR) of all-cause mortality (P for trend < 0.0001). Specifically, compared with the lowest ALP tertile, the adjusted HR of all-cause mortality in the highest tertile was 4.21 (95% confidence interval 2.03-8.71). In subgroup of patients with stable or unstable angina, a similar association was noted (P for trend < 0.0001). In terms of cardiovascular mortality, myocardial infarction, and stent thrombosis, the adjusted HRs in the highest ALP tertile were 3.92 (1.37-11.20), 1.98 (0.91-4.29), and 2.73 (1.33-5.61), respectively, compared with the lowest tertile. Furthermore, evaluation of both ALP and C-reactive protein provided better predictive value than either alone. Interesting result suggesting the mechanism was that ALP was significantly associated with the presence of angiographic coronary calcification (P for trend = 0.046).

CONCLUSION

Our study demonstrated that the higher serum ALP level is an independent predictor of mortality, myocardial infarction, and stent thrombosis in CAD patients after PCI with DES.

Secondary sphere formation enhances the functionality of cardiac progenitor cells

Loss of cardiomyocytes impairs cardiac function after myocardial infarction (MI). Recent studies suggest that cardiac stem/progenitor cells could repair the damaged heart. However, cardiac progenitor cells are difficult to maintain in terms of purity and multipotency when propagated in two-dimensional culture systems. Here, we investigated a new strategy that enhances potency and enriches progenitor cells. We applied the repeated sphere formation strategy (cardiac explant → primary cardiosphere (CS) formation → sphere-derived cells (SDCs) in adherent culture condition → secondary CS formation by three-dimensional culture). Cells in secondary CS showed higher differentiation potentials than SDCs. When transplanted into the infarcted myocardium, secondary CSs engrafted robustly, improved left ventricular (LV) dysfunction, and reduced infarct sizes more than SDCs did. In addition to the cardiovascular differentiation of transplanted secondary CSs, robust vascular endothelial growth factor (VEGF) synthesis and secretion enhanced neovascularization in the infarcted myocardium. Microarray pathway analysis and blocking experiments using E-selectin knock-out hearts, specific chemicals, and small interfering RNAs (siRNAs) for each pathway revealed that E-selectin was indispensable to sphere initiation and ERK/Sp1/VEGF autoparacrine loop was responsible for sphere maturation. These results provide a simple strategy for enhancing cellular potency for cardiac repair. Furthermore, this strategy may be implemented to other types of stem/progenitor cell-based therapy.

Efficacy of vasectomy reversal according to patency for the surgical treatment of postvasectomy pain syndrome

This study was conducted to assess outcomes (according to patency) of vasectomy reversal (VR) in qualified patients with postvasectomy pain syndrome (PVPS). A total of 32 patients with PVPS undergoing VR between January 2000 and May 2010 were examined retrospectively. Of these, 68.8% (22/32) completed a study questionnaire, either onsite at the outpatient clinic or via telephone interview. Preoperative clinical findings, preoperative and postoperative visual analogue scale (VAS) pain scores, patency and pregnancy rate and overall patient satisfaction were analyzed. For the latter, a four-point rating of (1) cure, (2) improvement, (3) no change or (4) recurrence was used. The mean age was 45.09±4.42 years and the mean period of follow-up was 3.22 years (0.74-7.41). Patency rates were 68.2% (15/22) and pregnancy rates were 36.4% (8/22). The mean VAS was 6.64±1.00 preoperatively and 1.14±0.71 postoperatively (P<0.001). The difference in the mean preoperative and postoperative VAS was 6.00±1.25 (4-8) in the patency group and 4.43±0.98 (3-6) in the no patency group (P=0.011). A significant difference in procedural satisfaction with surgical outcome was observed between patency and no patency groups (P=0.014). In conclusion, in PVPS patients requiring VR, a significant difference was observed between the patency and no patency groups in terms of pain reduction and the degree of patient procedural satisfaction.

Effects of a priming dose of fentanyl during anaesthesia on the incidence and severity of fentanyl-induced cough in current, former and non-smokers

Fentanyl is commonly used during anaesthesia and can cause fentanyl-induced cough (FIC). This study investigated whether a priming dose of fentanyl reduced FIC, and determined the factors associated with increased risk of FIC. Subjects undergoing elective surgery under general anaesthesia (n = 800) were randomized into four groups: group 1 received 2 μg/kg fentanyl bolus; groups 2, 3 and 4 received a priming dose of fentanyl 0.5 μg/kg followed by 1.5 μg/kg after 1, 2 or 3 min, respectively. The incidence of FIC was 17.0%, 10.0%, 12.5% and 11.5% for groups 1, 2, 3 and 4, respectively, with no significant between-group differences in FIC incidence or severity. The mean FIC onset time was 22 s. Former smokers were 2.91 times more likely than current smokers to experience cough. A fentanyl priming dose did not reduce the incidence and severity of FIC. Former smokers were hyper-reactive to fentanyl compared with current smokers.

Abstract 437: Simvastatin/Ezetimibe 20/10 mg Versus Atorvastatin 20 mg in Patients with Type 2 Diabetes: Results of Single-Center, Randomized Controlled Trial

Introduction Though the efficacy on traditional lipid parameters of simvastatin/ezetimibe and atorvastatin has been studied extensively, ApoB/ApoA1 ratio which has better predictive value for cardiovascular event has not been compared as a primary endpoint in these two treatment groups before, especially in diabetes.

Methods This study was a single center, open label, randomized phase 4 study to compare the efficacy and safety of simvastatin/ezetimibe 20/10mg versus atorvastatin 20mg once daily in subjects with type 2 diabetes. One hundred thirty-two well controlled diabetic patients (HbA1C <8.5%) with high LDL cholesterol levels (≥ 100mg/dL) were randomized to two groups. The primary endpoint was the difference in percent change of ApoB/ApoA1 ratio at 12 weeks and secondary endpoints were changes in conventional lipid profiles and apolipoproteins.

Results In total, 132 patients (66 for each group; 60 males; mean age, 64.6±7.6 years) were enrolled and 125 patients were included in the full analysis set (62 for simvastatin/ezetimibe; 63 for atorvastatin). Baseline characteristics including lipid profiles were comparable between two groups. After 12 weeks of treatment ApoB/ApoA1 ratio was significantly reduced in both groups, however the differences of % changes between two groups were statistically not significant (-38.1±17.9% vs. -34.2±16.2%, p =0.279) and the changes in conventional lipid profiles including total cholesterol, LDL cholesterol and triglyceride also showed no significant difference. However, HDL cholesterol and ApoA1 levels increased significantly in the simvastatin/ezetimibe group, whereas decreased in the atorvastatin group (HDL cholesterol 4.2±12.7% vs. -0.2±14.8% and ApoA1 2.8±10.0% vs. -1.8±9.8%, p =0.041 and 0.002). In per-protocol analysis, improvement of ApoB/ApoA1 was significantly greater in the simvastatin/ezetimibe group (-42.3±11.9% vs. -36.5±14.1%, p =0.031). The changes of HOMA index and hsCRP were comparable between two groups in full analysis set. But in per-protocol analysis, HOMA index and hsCRP decreased in the simvastatin/ezetimibe group whereas increased in the atorvastatin group although there was no statistic significance. The frequency of adverse reaction was comparable between two groups.

Conclusion Based on the results of this randomized controlled trial, simvastatin/ezetimibe 20/10mg might be preferable to atorvastatin 20mg for management of dyslipidemia in the patients with type 2 diabetes.

Recanalization with Wingspan stent for acute middle cerebral artery occlusion in failure or contraindication to intravenous thrombolysis: a feasibility study

BACKGROUND AND PURPOSE

Recanalization with the Wingspan stent, which can be deployed rapidly and safely, is an option for treating acute ischemic stroke when intravenous thrombolysis has failed or is contraindicated. This study was performed to evaluate feasibility, efficacy, and safety of recanalization for acute middle cerebral artery occlusion using the Wingspan stent.

MATERIALS AND METHODS

We collected 10 patients with acute MCA occlusion in whom recanalization was not achieved with a standard intravenous thrombolysis, or who were ineligible for intravenous thrombolysis, or who presented after 3 hours of symptom onset and in whom the stent placement could be completed within 8 hours from symptom onset. We analyzed angiographic and clinical results.

RESULTS

Successful recanalization with the Wingspan stent was achieved in all patients. The mean NIHSS score on admission was 12.7 points (range 4-21). The occlusion sites were located in the 1st segment (n = 7; 2 left, 5 right) and 2nd segment (n = 3, all right) of the MCA. The mean time interval from stroke symptom onset to stent placement was 344.8 ± 76.3 minutes. No intracranial hemorrhage, vessel perforations, or dissections occurred in any patient. Nine patients improved on the NIHSS at 7 days. One patient did not have a change in the NIHSS score, even though the occluded artery was completely recanalized. At 7 days, the NIHSS score of all patients was 4.4 ± 4.7 (median 4, range 0-13). At discharge, an mRS of ≤ 3 was achieved in all patients and an mRS of ≤ 2 was achieved in 7 patients (70%).

CONCLUSIONS

This small case series demonstrates the feasibility of using the Wingspan stent safely and effectively for MCA occlusions when standard treatments are ineffective or not available.

New method to differentiate human peripheral blood monocytes into insulin producing cells: Human hematosphere culture

Strategy to differentiate stem cells into insulin producing cells (IPCs) in vitro has been a promising one to get cell source of β-cell replacement therapy for diabetes. It has been suggested that islets and neurons share features and nestin-positive cells could differentiate into IPCs. We have recently developed a three-dimensional culture system using human peripheral blood cells named as blood-born hematosphere (BBHS). Here we showed that most of BBHS were composed of nestin-positive cells. Under the four-stage differentiation protocol for IPCs, we plated nestin-positive BBHS onto fibronectin-coated dish. These cells form islet-like clusters and most of them expressed insulin. Pancreatic specific genes were turned on, such as transcription factors (Pdx-1, Ngn3 and Nkx6.1), genes related to endocrine function (Glut-2 and PC2) or β cell function (Kir6.2, SUR1). Furthermore islet differentiation was confirmed by dithizone (DTZ) staining to detect zinc ion which binds insulin protein within the cells. Finally, IPCs derived from BBHS showed capability to secrete insulin in response to glucose stimulation. Taken together, our novel protocol successfully induced islet-like human insulin producing cells out of BBHS. This strategy of ex vivo expansion of IPCs using BBHS provides an autologous therapeutic cell source for the treatment of diabetes.

Posterior Reversible Encephalopathy Syndrome in Early Postpartum Woman

There have been reports about posterior reversible encephalopathy syndrome (PRES) associated with pregnancy, especially peripartum. However, the pathophysiology of PRES is not still clear. Tonic-clonic seizure occurred during early postpartum in a woman with the tendency toward pre-eclampsia developed after vaginal delivery followed by emergency cesarean hysterectomy. Postictal findings included headache, loss of vision, and short-term memory loss and magnetic resonance imaging (MRI) findings suggesting PRES were noted. Neurologic symptoms and cerebral lesions were gradually improved with immediate supportive managements.

Intravitreal bevacizumab and ranibizumab injections for patients with polypoidal choroidal vasculopathy

PURPOSE

To compare the effectiveness of intravitreal injection of bevacizumab and ranibizumab in patients with treatment-naïve polypoidal choroidal vasculopathy (PCV).

METHODS

A total of 66 and 60 eyes of 121 consecutive patients who received intravitreal bevacizumab (1.25 mg) or ranibizumab (0.5 mg) injection for treatment of PCV were retrospectively reviewed. After initial three loading injections by month, injection was performed as needed. Main outcome measures included best corrected visual acuity (BCVA), foveal center thickness (FCT) as assessed by spectral domain optical coherence tomography (SD-OCT), and change in polypoidal lesion on indocyanine green angiography (ICGA).

RESULTS

At 12 months, average number of injections was 4.72±1.84 in the bevacizumab group and 5.52±1.54 in the ranibizumab group. Mean logarithm of the minimum angle of resolution of BCVA from baseline at 12 months after injection improved by 0.11 in the bevacizumab group (P=0.02) and by 0.14 in the ranibizumab group (P=0.01). Average FCT decreased from 368±62.48 to 298±40.77 μm in the bevacizumab group (P=0.01) and from 371±50.79 to 286±36.93 μm in the ranibizumab group (P=0.01). Polyp regression rate was 24.2% (16 eyes out of 66 eyes) in the bevacizumab group and 23.3% (14 eyes out of 60 eyes) in the ranibizumab group. There was no statistically significant difference in BCVA improvement achieved, FCT improvement achieved, and polyp regression rate between groups.

CONCLUSION

Intravitreal injections of bevacizumab and ranibizumab have similar effects in stabilization of visual acuity, macular edema, and regression of polypoidal complex with PCV eyes.

Clinical outcomes of high on-treatment platelet reactivity in Koreans receiving elective percutaneous coronary intervention (from results of the CROSS VERIFY study)

Platelet reactivity after clopidogrel therapy varies among patients. Whether clopidogrel response variability can predict clinical outcomes has not been verified in Asians. A prospective cohort was analyzed to evaluate clinical impact of clopidogrel response variability in patients who underwent elective percutaneous coronary intervention (PCI). A total of 809 consecutive patients receiving clopidogrel after elective PCI were followed for 1 year. On-treatment platelet reactivity (OPR) after clopidogrel therapy was measured with a point-of-care test, the VerifyNow P2Y12 assay. The primary end point was the composite of cardiac death and nonfatal myocardial infarction (MI) at 1 year. In this exclusively Korean cohort, the median OPR was 236 P2Y12 reactivity units. Using the definition of OPR ≥235 P2Y12 reactivity units as high OPR (HOPR), 50.3% of the cohort showed HOPR. The group with HOPR had significantly higher rates of cardiac death and spontaneous MI (2.5% vs 0.5%, p = 0.022) than the group without HOPR. Multivariate-adjusted analysis showed that HOPR was an independent predictor of the composite of cardiac death and nonfatal MI. The difference in major adverse cardiac events between the groups with and without HOPR was more profound in those without major cardiovascular disease, such as hypertension, diabetes mellitus, or dyslipidemia. In conclusion, HOPR to clopidogrel was significantly associated with cardiac death and spontaneous MI after elective PCI, suggesting that clopidogrel response variability may be a significant risk factor of hard end points in Koreans.

N-cadherin determines individual variations in the therapeutic efficacy of human umbilical cord blood-derived mesenchymal stem cells in a rat model of myocardial infarction

In this study, we established and characterized human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) from four different donors. However, the hUCB-MSCs showed remarkable variations in their therapeutic efficacy for repairing rat infarcted myocardium (including the process of angiogenesis) 8 weeks after transplantation. In addition, we observed that the level of vascular endothelial growth factor (VEGF) is correlated with the therapeutic efficacy of the four hUCB-MSCs. Next, to investigate the practical application of hUCB-MSCs, we searched for surface signature molecules that could serve as indicators of therapeutic efficacy. The gene for N-cadherin was the only cell surface gene that was highly expressed in the most effective hUCB-MSCs, both at the transcriptional and translational levels. We observed downregulation and upregulation of VEGF in response to N-cadherin blocking and N-cadherin overexpression, respectively. Activation of extracellular signal-regulated kinase (ERK), but not protein kinase B, was increased when N-cadherin expression was increased, whereas disruption of N-cadherin-mediated cell-cell contact induced suppression of ERK activation and led to VEGF downregulation. Moreover, by investigating hUCB-MSCs overexpressing N-cadherin or N-cadherin knockdown hUCB-MSCs, we confirmed the in vivo function of N-cadherin. In addition, we observed that DiI-labeled hUCB-MSCs express N-cadherin in the peri-infarct area and interact with cardiomyocytes.

Multimodality imaging can help to doubt, diagnose and follow-up cardiac mass

Primary cardiac lymphoma is a very rare form of lymphoma primarily or mainly involving the heart, as in the two cases presented in this report. Various imaging modalities, including coronary computed tomography angiography, cardiac magnetic resonance imaging and positron emission tomography were useful for the characterization and diagnosis of cardiac mass. Pathologic confirmation was successful with endomyocardial biopsy under echocardiographic guidance, intra- and extracardiacally. In primary cardiac lymphoma, diagnosis using multiple modalities may be useful for mass characterization, and for response monitoring after chemotherapy.

Stent coated with antibody against vascular endothelial-cadherin captures endothelial progenitor cells, accelerates re-endothelialization, and reduces neointimal formation

OBJECTIVE

In contrast to CD34, vascular endothelial-cadherin (VE-cadherin) is exclusively expressed on the late endothelial progenitor cells (EPC) whereas not on the early or myeloid EPC. Thus, VE-cadherin could be an ideal target surface molecule to capture circulating late EPC. In the present study, we evaluated whether anti-VE-cadherin antibody-coated stents (VE-cad stents) might accelerate endothelial recovery and reduce neointimal formation through the ability of capturing EPC.

METHODS AND RESULTS

The stainless steel stents were coated with rabbit polyclonal anti-human VE-cadherin antibodies and exposed to EPC for 30 minutes in vitro. The number of EPC that adhered to the surface of VE-cad stents was significantly higher than bare metal stents (BMS) in vitro, which was obliterated by pretreatment of VE-cad stent with soluble VE-cadherin proteins. We deployed VE-cad stents and BMS in the rabbit right and left iliac arteries, respectively. At 48 hours after stent deployment in vivo, CD-31-positive endothelial cells adhered to VE-cad stent significantly more than to BMS. At 3 days, scanning electron microscopy showed that over 90% surface of VE-cad stents was covered with endothelial cells, which was significantly different from BMS. At 42 days, neointimal area that was filled with smooth muscle cells positive for actin or calponin was significantly smaller in VE-cad stents than in BMS by histological analysis (0.95±0.22 versus 1.34±0.43 mm(2), respectively, P=0.02). Immuno-histochemical analysis revealed that infiltration of inflammatory cells was not significantly different between 2 stents.

CONCLUSIONS

VE-cad stents captured EPC successfully in vitro, accelerated endothelial recovery on stent, and eventually reduced neointimal formation in vivo.

Peroxisome proliferator-activated receptor-δ activates endothelial progenitor cells to induce angio-myogenesis through matrix metallo-proteinase-9-mediated insulin-like growth factor-1 paracrine networks

AIMS

The roles of peroxisome proliferator-activated receptor (PPAR)-δ in vascular biology are mainly unknown. We investigated the effects of PPAR-δ activation on the paracrine networks between endothelial progenitor cells (EPCs) and endothelial cells (ECs)/skeletal muscle.

METHODS AND RESULTS

Treatment of EPCs with GW501516, a PPAR-δ agonist, induced specifically matrix metallo-proteinase (MMP)-9 by direct transcriptional activation. Subsequently, this increased-MMP-9 broke down insulin-like growth factor-binding protein (IGFBP)-3, resulting in IGF-1 receptor (IGF-1R) activation in surrounding target cells. Treatment of conditioned medium from GW501516-stimulated EPCs enhanced the number and functions of human umbilical vein ECs and C2C12 myoblasts via MMP-9-mediated IGF-1R activation. Systemic administration of GW501516 in mice increased MMP-9 expression in EPCs, and augmented IGFBP-3 degradation in serum. In a mouse hindlimb ischaemia model, systemic treatment of GW501516 or local transplantation of GW501516-treated EPCs induced IGF-1R phosphorylation in ECs and skeletal muscle in the ischaemic limbs, leading to augmented angiogenesis and skeletal muscle regeneration. It also enhanced wound healing with increased angiogenesis in a mouse skin punch wound model. These pro-angiogenic and muscle-regenerating effects were abolished by MMP-9 knock-out.

CONCLUSION

Our results suggest that PPAR-δ is a crucial modulator of angio-myogenesis via the paracrine effects of EPCs, and its agonist is a good candidate as a therapeutic drug for patients with peripheral vascular diseases.