Paclitaxel exerts antiplatelet and antithrombotic activities: Additional benefit from use of paclitaxel-coated balloons and -eluting stents in coronary revascularization and prevention of in-stent restenosis.

INTRODUCTION: Paclitaxel is a microtubule-stabilizing drug used to treat several types of cancer, including ovarian and breast cancer. Because of its antiproliferative effect on vascular smooth muscle cells, balloons and stents are coated with paclitaxel for use in coronary revascularization and prevention of in-stent restenosis (ISR). However, mechanisms underlying ISR are complicated. Platelet activation is one of the major causes of ISR after percutaneous coronary intervention. Although the antiplatelet activity of paclitaxel was noted in rabbit platelets, the effect of paclitaxel on platelets remains unclear. This study investigated whether paclitaxel exhibits antiplatelet activity in human platelets. METHODS AND RESULTS: Paclitaxel inhibited platelet aggregation induced by collagen but not that induced by thrombin, arachidonic acid, or U46619, suggesting that paclitaxel is more sensitive to the inhibition of collagen-induced platelet activation. Moreover, paclitaxel blocked collagen receptor glycoprotein (GP) VI downstream signaling molecules, including Lyn, Fyn, PLCγ2, PKC, Akt, and MAPKs. However, paclitaxel did not directly bind to GPVI and cause GPVI shedding, as detected by surface plasmon resonance and flow cytometry, respectively, indicating that paclitaxel may interfere with GPVI downstream signaling molecules, such as Lyn and Fyn. Paclitaxel also prevented granule release and GPIIbIIIa activation induced by collagen and low convulxin doses. Moreover, paclitaxel attenuated pulmonary thrombosis and delayed platelet thrombus formation in mesenteric microvessels without significantly affecting hemostasis. CONCLUSION: Paclitaxel exerts antiplatelet and antithrombotic effects. Thus, paclitaxel may provide additional benefits beyond its antiproliferative effect when used in drug-coated balloons and drug-eluting stents for coronary revascularization and prevention of ISR.

Non-prompt surgery for patients with acute type A aortic dissection without pre-operative shock and malperfusion.

Background: Acute type A aortic dissection (ATAAD) requires urgent surgical treatment. However, during daily practice, there were some patients with ATAAD sought for medical attention several days after symptoms occurred and some other patients hesitated to receive aortic surgery after the diagnosis of ATAAD was made. This study aims to investigate the surgical outcomes of non-prompt aortic surgery (delayed diagnosis caused by the patient or delayed surgery despite immediate diagnosis) for ATAAD patients. Methods: From November 2004 to June 2020, of more than 200 patients with ATAAD patients who underwent aortic surgery at our hospital, there were 30 patients without pre-operative shock and malperfusion who sought for medical attention with symptoms for several days or delayed aortic surgery several days later despite ATAAD was diagnosed. Of the 30 patients (median age 60.9, range 33.4~82.5 years) in the study group, there were 18 patients undergoing surgery when they arrived at our hospital (delayed diagnosis by the patient) and 12 patients receiving surgery days later (delayed surgery despite immediate diagnosis). Patients with prompt surgery after symptom onset (control group) were matched from our database by propensity score matching. The surgical mortality rate and post-operative morbidities were compared between the study group and control group. Results: The in-hospital mortality was 3.3% for the study group and 6.7% for the control group (p = non-significant). The incidence of post-operative cerebral permanent neurological defect was 0% for the study group and 13.3% for the control group (p = 0.112). There were three patients receiving aortic re-intervention or re-do aortic surgery during follow-up for the study group and two patients for the control group. Conclusion: Prompt surgery for ATAAD is usually a good choice if everything is well prepared. Besides, urgent but non-prompt aortic surgery could also provide acceptable surgical results for ATAAD patients without pre-operative shock and malperfusion who did not seek medical attention or who could not make their minds to undergo surgery immediately after symptom onset. Hospitalization with intensive care is very important for pre-operative preparation and monitoring for the patients who decline prompt aortic surgery.

Retrograde cerebral perfusion for surgery of type A aortic dissection.

BACKGROUND: For type A aortic dissection (TAAD), antegrade cerebral perfusion (ACP) was proposed as a more physiological method than retrograde cerebral perfusion (RCP) for intra-operative brain protection, but it is still debatable whether antegrade cerebral perfusion (ACP) or retrograde cerebral perfusion (RCP) is related to the better clinical outcome. The present study was undertaken to compare the results in our patients receiving surgery for TAAD with ACP or RCP. The primary aim of this study was focused on the incidence of and the factors associated with surgical mortality, post-operative neurological outcomes and long-term survival. METHODS: From February 2001 to March 2019, there were 223 consecutive patients with TAAD treated surgically at our hospital. The median age at presentation was 56 years (range 29-88 years) and 70 patients (31.4%) over 65 years of age. There were 168 patients treated with RCP and 55 patients treated with ACP. The primary endpoints were surgical mortality and neurological outcome. Propensity score matching was used to compare the treatment results of surgeries with RCP or ACP. The long-term survival was also analyzed. RESULTS: The overall in-hospital mortality rate and the overall 30-day mortality rate were 15.6% and 14.3% respectively. For the patients without pre-operative shock (n = 184), the in-hospital mortality rate was 10.3% and the 30-day mortality rate was 8.7% and higher long-term survival rates (88.3% for 5 years, 86.5% for 10 years, 86.5% for 15 years) were documented for this patient group. There was no significant difference on the surgical mortality between the ACP group and the RCP group. In the entire cohort, there were 23 patients (10.3%) who suffered from post-operative neurological deficits (PND) and there were less PND for the patients with RCP than the patients with ACP (7.7% vs 18.1%, p = 0.027). After propensity score matching, there was still higher incidence of PND in the ACP group than in the RCP group but without statistical significance (18.5% vs 11.1%, p = 0.279). CONCLUSIONS: Aortic surgery carries high risk for the patients with TAAD and PND is not an unusual post-operative morbidity. In our series, pre-operative shock, pre-operative CPR, CRI, past history with CAD are related to higher surgical mortality. The younger patients (<65 years old) without pre-operative shock got better surgical outcome and long-term survival. RCP could provide acceptable cerebral protection during aortic surgery for the TAAD patients. Old age, pre-operative shock, CRI and past history of CAD are independent risk factors for long-term survival.

Heart Transplantation Under Biventricular Mechanical Circulatory Support for Fulminant Myocarditis After a Bee Sting: A Case Report.

BACKGROUND Venom related fulminant myocarditis is uncommon. The clinical course varies, and histopathology is usually unclear, however, refractory cardiogenic shock is rare. CASE REPORT We reported a case of a 36-year-old female who developed fever and cardiogenic shock 3 days after a bee sting. Cardiac angiography showed patent coronary arteries and severely compromised left ventricular function. Her hemodynamics remained unstable under high dose inotropic agents and intra-aortic balloon pump support. In-hospital cardiac arrest occurred 4 hours after admission and she received extracorporeal cardiopulmonary resuscitation. Her peripheral venoarterial extracorporeal membrane oxygenation (VA ECMO) was shifted to bilateral ventricular assisted devices (VAD) due to progressive right heart failure. The endomyocardial biopsy result was compatible with the picture of hypersensitivity myocarditis. Her heart went into persistent standstill under mechanical circulatory support. She underwent heart transplantation on hospital day 49 and remained clinically stable 6 months after discharge. CONCLUSIONS This is the first reported case of fulminant hypersensitivity myocarditis following a bee sting. ECMO and VAD could be used as bridge to a successful heart transplantation.

Staged surgical repair for infants with interrupted aortic arch.

BACKGROUND: Interrupted aortic arch (IAA) is a rare congenital cardiac anomaly, which necessitates surgical treatment. There are several surgical strategies for corrective repair of IAA, such as one-stage repair, rapid two-stage repair and two-stage repair. Here, we reported our surgical result of staged-repair policy for the patients with IAA. METHOD: From November 2003 to July 2015, there were 14 patients (8 boys, 6 girls) with IAA treated by us. Except one teenager patient, we routinely used intravenous infusion of prostaglandin E1 for all the infant patients (n = 13) to keep adequate end organ perfusion before the first surgical intervention. Surgical repair was performed after the perfusion of end organs recovered. RESULT: Two patients (1 teenager and 1 infant with one-stage surgery) were excluded from this study. At the time of the first surgery, we did the first-stage surgery with anastomosis in between aortic arch and descending aorta, division of patent ductus arteriosus and banding of pulmonary trunk through left thoracotomy. The overall surgical survival rate of the first surgery was 100% (12/12). At the time of the second surgery, corrective repair was done under cardiopulmonary bypass through median sternotomy. The surgical survival rate of the corrective surgery was also 100%. There is no late death during follow-up for 9 years (range 4.2-15.0 years). CONCLUSION: Out of several surgical strategies for the infants with IAA, staged repair still could be a treatment option to achieve satisfied surgical result.

[Corrigendum] Nobiletin, a citrus flavonoid, activates vasodilator-stimulated phosphoprotein in human platelets through non­cyclic nucleotide­related mechanisms.

Following the publication of the above paper, the authors noted that the first author affiliation was presented incorrectly. Essentially, 'School of Medicine' had been omitted from the address. Therefore, the author and affiliation details for this paper should have been presented as follows (the changes are highlighted in bold): THANASEKARAN JAYAKUMAR1*, KAO­CHANG LIN1,2*, WAN-JUNG LU1,3, CHIA­YING LIN4, GERALDINE PITCHAIRAJ5, JIUN­YI LI4,6 and JOEN­RONG SHEU1,4. 1Department of Pharmacology, School of Medicine, College of Medicine, Taipei Medical University, Taipei; 2Department of Neurology, Chi Mei Medical Center, Tainan; 3Department of Medical Research, Taipei Medical University Hospital; 4Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan, R.O.C.; 5Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu, India; Department of Cardiovascular Surgery, Mackay Memorial Hospital, and Mackay Medical College, Taipei, Taiwan, R.O.C. The authors regret that the error with the first author affiliation was not noticed prior to the publication of their paper, and apologize for any inconvenience caused. [The original article was published in International Journal of Molecular Medicine 39: 174­182, 2017; DOI: 10.3892/ijmm.2016.2822].

[Corrigendum] Structure­activity relationship of three synthesized benzimidazole­based oligosaccharides in human platelet activation.

Following the publication of the above paper, the authors noted that the third author affiliation was presented incorrectly. The third author affiliation should have been written as 'Department of Pharmacology, School of Medicine, College of Medicine, and Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 110, Taiwan'. Therefore, the author and affiliation details for this paper should have been presented as follows (the changes are highlighted in bold): YI CHANg1­3*, WEN­HsIEN HsU2,4*, WEN­BIN YANg5, THANAsEKARAN JAYAKUMAR3, TZU­YIN LEE3, JOEN­RONg sHEU3, WAN­JUNg LU3,6 and JIUN­YI LI3,7. 1Department of Anesthesiology, Shin Kong Wu Ho­Su Memorial Hospital, Taipei 111; 2School of Medicine, Fu­Jen Catholic University, Xin Zhuang, New Taipei City 242; 3Department of Pharmacology, School of Medicine, College of Medicine, and Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 110; 4Department of Surgery, Wan­Fang Hospital, Taipei Medical University, Taipei 116; 5Genomics Research Center, Academia Sinica, Taipei 115; 6Department of Medical Research and Translational Laboratory, Research Department, Taipei Medical University Hospital, Taipei 110; 7Department of Cardiovascular Surgery, Mackay Memorial Hospital, and Mackay Medical College, Taipei 104, Taiwan, R.O.C.. The authors regret that the error with the third author affiliation was not noticed prior to the publication of their paper, and apologize for any inconvenience caused. [The original article was published in International Journal of Molecular Medicine 40: 1520­1528, 2017; DOI: 10.3892/ijmm.2017.3133].

Suppression of Human Platelet Activation via Integrin αIIbß3 Outside-In Independent Signal and Reduction of the Mortality in Pulmonary Thrombosis by Auraptene.

Auraptene is the most abundant coumarin derivative from plants. The pharmacological value of this compound has been well demonstrated, especially in the prevention of cancer and neurodegenerative diseases. Platelet activation is a major factor contributing to arterial thrombosis. Thus, this study evaluated the influence of auraptene in platelet aggregation and thrombotic formation. Auraptene inhibited platelet aggregation in human platelets stimulated with collagen only. However, auraptene was not effective in inhibiting platelet aggregation stimulated with thrombin, arachidonic acid, and U46619. Auraptene also repressed ATP release, [Ca2+]i mobilization, and P-selectin expression. Moreover, it markedly blocked PAC-1 binding to integrin αIIbß3. However, it had no influence on properties related to integrin αIIbß3-mediated outside-in signaling, such as the adhesion number, spreading area of platelets, and fibrin clot retraction. Auraptene inhibited the phosphorylation of Lyn-Fyn-Syk, phospholipase Cγ2 (PLCγ2), protein kinase C (PKC), Akt, and mitogen-activated protein kinases (MAPKs; extracellular-signal-regulated kinase (ERK1/2), and c-Jun N-terminal kinase (JNK1/2), but not p38 MAPK). Neither SQ22536, an adenylate cyclase inhibitor, nor ODQ, a guanylate cyclase inhibitor, reversed the auraptene-mediated inhibition of platelet aggregation. Auraptene reduced mortality caused by adenosine diphosphate (ADP)-induced pulmonary thromboembolism. In conclusion, this study provides definite evidence that auraptene signifies a potential therapeutic agent for preventing thromboembolic disorders.

Embelin as a Novel Inhibitor of PKC in the Prevention of Platelet Activation and Thrombus Formation.

Embelin is a quinone derivative and found in the fruits of Embelia ribes Burm.f. Embelin has been identified as a small molecular inhibitor of X-chromosome-linked inhibitor of apoptosis proteins, and has multiple biological activities, including antioxidation, anti-inflammation, and antitumor effects. However, the effect of embelin in platelets remains unclear. Thus, this study investigated the antiplatelet mechanism of embelin. Our data revealed that embelin could inhibit platelet aggregation induced by various agonists, including the protein kinase C (PKC) activator phorbol 12,13-dibutyrate (PDBu). Embelin, as well as the PKC inhibitor Ro 31-8220, markedly reduced PDBu-mediated phosphorylation of the PKC substrate, suggesting that embelin may be a PKC inhibitor for platelets. Embelin could block PKC downstream signaling and events, including the inhibition of protein kinase B and mitogen-activated protein kinase activation, granule release, and glycoprotein IIbIIIa activation. Moreover, embelin could delay thrombus formation in the mesenteric microvessels of mice, but did not significantly affect the tail bleeding time. In conclusion, we demonstrated that embelin is a PKC inhibitor and possesses antiplatelet and antithrombotic effects. The further analysis is necessary to more accurately determine clinical therapeutic potential of embelin in all clinical thromboembolic events with disturbance of thrombocyte function.

[Corrigendum] Novel iridium (III)­derived organometallic compound for the inhibition of human platelet activation.

After the publication of the above paper, the authors noted that an incomplete version of the address was presented for the second author affiliation; essentially, 'School of Medicine' had been omitted from the address. Therefore, the author and affiliation details for this paper should have been presented as follows: Kou­Gi Shyu1,2, Marappan Velusamy3, Chih­Wei Hsia2, Chih­Hao Yang2, Chih­Hsuan Hsia2, Duen­Suey Chou2, Thanasekaran Jayakumar2, Joen­Rong Sheu2 And Jiun­Yi Li2,4. 1Division of Cardiology, Shin Kong Wu Ho­Su Memorial Hospital, Taipei 111; 2Graduate Institute of Medical Sciences and Department of Pharmacology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan, R.O.C.; 3Department of Chemistry, North Eastern Hill University, Shillong, Meghalaya 793022, India; 4Department of Cardiovascular Surgery, Mackay Memorial Hospital, and Mackay Medical College, Taipei 104, Taiwan, R.O.C. The authors regret that the error with the second author affiliation was not noticed prior to the publication of their paper, and apologize for any inconvenience caused. [the original article was published in International Journal of Molecular Medicine 41: 2589­2600, 2018; DOI: 10.3892/ijmm.2018.3472].

Novel iridium (III)­derived organometallic compound for the inhibition of human platelet activation.

Since cisplatin achieved clinical success, transition metal platinum (Pt) drugs have been effectively used for the treatment of cancer. Iridium (Ir) compounds are considered to be potential alternatives to Pt compounds, as they possess promising anticancer effects with minor side effects. Platelet activation is associated with the metastasis and progression of cancer, and also with arterial thrombosis. Therefore, it is necessary to develop novel, effective antithrombotic agents. An Ir (III)­derived complex, [Ir (Cp*) 1­(2­pyridyl)­3­(3­methoxyphenyl)imidazo[1,5­a]pyridine Cl]BF4 (Ir­3), was developed as a novel antiplatelet drug. Ir­3 exerted more potent inhibitory activity on platelet aggregation stimulated by collagen compared with other agonists, including thrombin. In collagen­activated platelets, Ir­3 also inhibited adenosine trisphosphate release, intracellular Ca+2 mobilization and surface P­selectin expression, as well as the phosphorylation of phospholipase Cγ2 (PLCγ2), protein kinase C (PKC), protein kinase B (Akt) and c­Jun N­terminal kinase (JNK) 1, but not p38 mitogen­activated protein kinase or extracellular signal­regulated kinases. Ir­3 did not markedly affect phorbol 12, 13­dibutyrate­stimulated platelet aggregation. Neither the adenylate cyclase inhibitor SQ22536 nor the guanylate cyclase inhibitor 1H­[1, 2, 4] oxadiazolo [4,3­a]quinoxalin­1­one significantly reversed the Ir­3­mediated inhibition of platelet aggregation. Furthermore, Ir­3 had no considerable diminishing effects on OH radical signals in collagen­stimulated platelets or Fenton reaction solution. In conclusion, Ir­3 serves a novel function in the inhibition of platelet aggregation through inhibiting the PLCγ2­PKC cascade, and the subsequent suppression of Akt and JNK1 activation. Therefore, Ir­3 may be a potential novel therapeutic agent for the treatment of thromboembolic disorders, or the interplay between platelets and tumor cells which contributes to tumor cell proliferation and progression.

New Therapeutic Agent against Arterial Thrombosis: An Iridium(III)-Derived Organometallic Compound.

Platelet activation plays a major role in cardio and cerebrovascular diseases, and cancer progression. Disruption of platelet activation represents an attractive therapeutic target for reducing the bidirectional cross talk between platelets and tumor cells. Platinum (Pt) compounds have been used for treating cancer. Hence, replacing Pt with iridium (Ir) is considered a potential alternative. We recently developed an Ir(III)-derived complex, [Ir(Cp*)1-(2-pyridyl)-3-(2-hydroxyphenyl)imidazo[1,5-a]pyridine Cl]BF4 (Ir-11), which exhibited strong antiplatelet activity; hence, we assessed the therapeutic potential of Ir-11 against arterial thrombosis. In collagen-activated platelets, Ir-11 inhibited platelet aggregation, adenosine triphosphate (ATP) release, intracellular Ca2+ mobilization, P-selectin expression, and OH· formation, as well as the phosphorylation of phospholipase Cγ2 (PLCγ2), protein kinase C (PKC), mitogen-activated protein kinases (MAPKs), and Akt. Neither the adenylate cyclase inhibitor nor the guanylate cyclase inhibitor reversed the Ir-11-mediated antiplatelet effects. In experimental mice, Ir-11 prolonged the bleeding time and reduced mortality associated with acute pulmonary thromboembolism. Ir-11 plays a crucial role by inhibiting platelet activation through the inhibition of the PLCγ2-PKC cascade, and the subsequent suppression of Akt and MAPK activation, ultimately inhibiting platelet aggregation. Therefore, Ir-11 can be considered a new therapeutic agent against either arterial thrombosis or the bidirectional cross talk between platelets and tumor cells.

Ketamine, a Clinically Used Anesthetic, Inhibits Vascular Smooth Muscle Cell Proliferation via PP2A-Activated PI3K/Akt/ERK Inhibition.

Abnormal proliferation of vascular smooth muscle cells (VSMCs) gives rise to major pathological processes involved in the development of cardiovascular diseases. The use of anti-proliferative agents for VSMCs offers potential for the treatment of vascular disorders. Intravenous anesthetics are firmly established to have direct effects on VSMCs, resulting in modulation of blood pressure. Ketamine has been used for many years in the intensive care unit (ICU) for sedation, and has recently been considered for adjunctive therapy. In the present study, we investigated the effects of ketamine on platelet-derived growth factor BB (PDGF-BB)-induced VSMC proliferation and the associated mechanism. Ketamine concentration-dependently inhibited PDGF-BB-induced VSMC proliferation without cytotoxicity, and phosphatidylinositol 3-kinase (PI3K) and extracellular signal-regulated protein kinase (ERK) inhibitors, LY294002 and PD98059, respectively, have similar inhibitory effects. Ketamine was shown to attenuate PI3K, Akt, and ERK1/2 phosphorylation induced by PDGF-BB. Okadaic acid, a selective protein phosphatase 2A (PP2A) inhibitor, significantly reversed ketamine-mediated PDGF-BB-induced PI3K, Akt, and ERK1/2 phosphorylation; a transfected protein phosphatse 2a (pp2a) siRNA reversed Akt and ERK1/2 phosphorylation; and 3-O-Methyl-sphingomyeline (3-OME), an inhibitor of sphingomyelinase, also significantly reversed ERK1/2 phosphorylation. Moreover, ketamine alone significantly inhibited tyrosine phosphorylation and demethylation of PP2A in a concentration-dependent manner. In addition, the pp2a siRNA potently reversed the ketamine-activated catalytic subunit (PP2A-C) of PP2A. These results provide evidence of an anti-proliferating effect of ketamine in VSMCs, showing activation of PP2A blocks PI3K, Akt, and ERK phosphorylation that subsequently inhibits the proliferation of VSMCs. Thus, ketamine may be considered a potential effective therapeutic agent for reducing atherosclerotic process by blocking the proliferation of VSMCs.

Structure-activity relationship of three synthesized benzimidazole-based oligosaccharides in human platelet activation.

Antiplatelet agents have considerable benefits in the treatment of thromboembolic diseases; however, these agents still have substantial limitations due to their severe side-effects. In this study, the antiplatelet activity of three newly synthesized saccharide based benzimidazole derivatives, M3BIM, Malto-BIM and Melibio-BIM, in collagen and thrombin-stimulated human platelets in vitro was examined. Among the compounds tested, only compound M3BIM exerted concentration (20-60 µM)-dependent inhibitory effects against collagen (1 µg/ml) and thrombin (0.01 U/ml)-induced washed human platelet aggregation. Moreover, at a concentration of 60 µM, M3BIM distinctly abolished collagen-induced adenosine triphosphate (ATP) release and intracellular Ca2+ mobilization. Additionally, this compound attenuated the collagen-induced phosphorylation of p47, a marker of the activation of protein kinase C (PKC) and p38 mitogen-activated protein kinase (MAPK). However, Malto-BIM and Melibio-BIM were not effective in this regard. Moreover, the toxic effects of these compounds were evaluated using zebrafish embryo toxicity (ZET) assay, and the results revealed that all three compounds had no comparative cytotoxicity within the range of 25-200 µM. Overall, the results of this study provide evidence for the inhibitory effects of M3BIM on collagen-induced platelet aggregation in vitro compared to other imidazole derivatives. The presence of 1-imidazolyl moiety at one end with a longer chain length (three sugar moieties) may be mainly responsible for the observed effects of M3BIM. These results suggest that compound M3BIM may be used as a potential candidate for the treatment of aberrant platelet activation-related diseases as it inhibits the activation of p47 and p38 MAPK, and reduces ATP release and Ca2+ mobilization.

Nobiletin, a citrus flavonoid, activates vasodilator-stimulated phosphoprotein in human platelets through non-cyclic nucleotide-related mechanisms.

Nobiletin, a bioactive polymethoxylated flavone, has been described to possess a diversity of biological effects through its antioxidant and anti-inflammatory properties. Vasodilator-stimulated phosphoprotein (VASP) is a common substrate for cyclic AMP and cyclic GMP-regulated protein kinases [i.e., cyclic AMP-dependent protein kinase (PKA; also known as protein kinase A) and cyclic GMP-dependent protein kinase (PKG; also known as protein kinase G)] and it has been shown to be directly phosphorylated by protein kinase C (PKC). In the present study, we demonstrate that VASP is phosphorylated by nobiletin in human platelets via a non-cyclic nucleotide-related mechanism. This was confirmed by the use of inhibitors of adenylate cyclase (SQ22536) and guanylate cyclase [1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ)], since they prevented VASP phosphorylation induced by nobiletin. Furthormore, this event was also not affected by specific inhibitors of PKA (H-89), PKG (KT5823) and PKC (Ro318220), representing cyclic nucleotide-dependent pathways upon nobiletin-induced VASP phosphorylation. Similarly, inhibitors of p38 mitogen-activated protein kinase (MAPK; SB203580), extracellular signal-regulated kinase 2 (ERK2; PD98059), c-Jun N-terminal kinase 1 (JNK1; SP600125), Akt (LY294002) and nuclear factor-κB (NF-κB; Bay11-7082) did not affect nobiletin­induced VASP phosphorylation. Moreover, electron spin resonance, dichlorofluorescein fluorescence and western blotting techniques revealed that nobiletin did not affect hydroxyl radicals (OH•), intracellular reactive oxygen species (ROS) and on protein carbonylation, respectively. Furthermore, the nobiletin­induced VASP phosphorylation was surprisingly reversed by the intracellular antioxidant, N-acetylcysteine (NAC), but not by the inhibitor of NADPH oxidase, diphenyleneiodonium chloride (DPI). It was surprising to observe the differential effects of nobiletin and NAC on VASP phosphorylation in human platelets, since they both have been reported to have antioxidant properties. The likely explanation for this discrepancy is that NAC may bind to allosteric sites on the receptor different from those that nobiletin binds to in human platelets. Taken together, our findings suggest that nobiletin induces VASP phosphorylation in human platelets through non-cyclic nucleotide-related mechanisms. Nevertheless, the exact mechanisms responsible for these effects need to be further confirmed in future studies.

Reduction of connexin43 in human endothelial progenitor cells impairs the angiogenic potential.

Our previous work showed that arsenic trioxide down-regulated Cx43 and attenuated the angiogenic potential of human late endothelial progenitor cells (EPC). However, the relation between Cx43 and angiogenic activity of the EPC remained unclear. In the study, human late EPC were treated with siRNA specific to Cx43 (Cx43siRNA). The expression profiles as well as activity of the treated cells were examined. In parallel, the angiogenic potential of human EPC treated with Cx43siRNA was evaluated using murine hind limb ischemic model. The results showed that, in the EPC treated with Cx43siRNA, the activity of migration, proliferation, and angiogenic potential were attenuated, accompanied by reduction in vascular endothelial growth factor (VEGF) expression. In hind limb ischemia mice, EPC treated with Cx43siRNA lost the therapeutic angiogenic potential. VEGF supplementation partially recovered the activity impaired by Cx43 down-regulation. In conclusion, reduced Cx43 expression per se in the EPC causes decreased expression of VEGF and impaired angiogenic potential of the cells. Prevention of Cx43 reduction is a potential target to maintain the angiogenic potential of the EPC.

[Difference in predictors of self efficacy and compliance between diabetic and non diabetic patients who underwent coronary artery bypass surgery].

BACKGROUND: Compared to their non-diabetic peers, diabetic patients who undergo coronary artery bypass surgery (CABG) face greater complications and poorer outcomes. Identifying related risk factors is essential to improving post-CABG outcomes in this vulnerable population. Improving self-efficacy and compliance can further improve patient outcomes over the long term. PURPOSE: This study compared differences in self-efficacy predictors and compliance between diabetic and non-diabetic patients who received coronary artery bypass surgery. METHOD: We used a cross-sectional design with convenience sampling. A total of 350 patients were recruited from two medical centers and one teaching hospital. Instruments used included a demographics questionnaire, chronic disease self-efficacy questionnaire and compliance scale. SPSS 17.0 for Windows was used to analyze data. RESULTS: Results found self-efficacy positively associated with compliance in both groups. The non-diabetic group had higher self-efficacy and lower compliance than the diabetic group. In the diabetic group, gender, compliance, education, employment status and marital status were all predictors of self-efficacy, with self-efficacy the single predictor of compliance. In the non-diabetic group, compliance, primary care provider, education, time since surgery, gender and exercise were predictors of self-efficacy. Self-efficacy, primary care provider, employee status prior surgery were all predictors of compliance. CONCLUSIONS: Results provide valuable information regarding the impact of diabetes on CABG patient outcomes and differences in predictors of self-efficacy and compliance between diabetic and non-diabetic patients. Healthcare providers can promote healthy behavior and enhance quality of life by providing patient support tailored to their characteristics and considering the factors associated with better self-efficacy vs. compliance.

Therapeutic angiogenesis of human early endothelial progenitor cells is enhanced by thrombomodulin.

OBJECTIVE: We examined the effect of thrombomodulin (TM) domains 2 and 3 (TMD23) on human early endothelial progenitor cells (EPCs). METHODS AND RESULTS: TM was expressed and released by human EPCs cultured from peripheral blood mononuclear cells (PBMCs). Addition of TMD23 (100 ng/mL) to the cultured PBMCs increased the colony-forming units, chemotactic motility, matrix metalloproteinase activity, and interleukin-8 secretion but decreased tumor necrosis factor-α (TNF-α) release. Analysis of the signal pathway showed that TMD23 activated Akt. Inhibition of phosphatidylinositol-3 kinase-Akt blocked the effects of TMD23 on chemotactic motility, matrix metalloproteinase-9, interleukin-8, and TNF-α. In hindlimb ischemia mice, laser Doppler perfusion imaging of the ischemic limb during the 21 days after arterial ligation showed that the perfusion recovered best with intraperitoneal infusion of TMD23 plus local injection of early EPCs, followed by either infusion of TMD23 or injection of the cells. Animals without either treatment had the worst results. Animals treated with TMD23 also had lower circulating and tissue levels of TNF-α. CONCLUSION: TM is expressed and released by human circulating EPCs. Exogenous TMD23 enhances the angiogenic potential of early EPCs in vitro through activation of phosphatidylinositol-3 kinase-Akt pathway. Coadministration of TMD23 plus early EPCs augments therapeutic angiogenesis of the EPCs in ischemic tissues.

Atrial gap junctions, NF-kappaB and fibrosis in patients undergoing coronary artery bypass surgery: the relationship with postoperative atrial fibrillation.

OBJECTIVES: We examined the role of atrial gap junctions, NF-kappaB and fibrosis in the occurrence of postoperative atrial fibrillation (AF) in patients undergoing coronary artery bypass graft (CABG) surgery. METHODS: Forty-five patients with sinus rhythm were randomly assigned to the beating heart (n = 22) or cardioplegic cardiac arrest (n = 23) technique for surgery. Of them, 14 patients experienced post-CABG AF. Atrial samples taken before and after CABG surgery were analyzed. RESULTS: During surgery, Cx43 and Cx40 proteins were significantly reduced (both p < 0.05) in the arrested heart group, but only mildly decreased in the beating heart group. However, the change of either connexin was not associated with AF. In contrast, patients with AF had a higher baseline expression of NF-kappaB and more fibrosis compared to those without AF (both p < 0.05). CONCLUSIONS: CABG surgery with the beating heart technique attenuated the reduction of atrial Cx43 and Cx40 compared to the cardioplegic cardiac arrest technique. Atrial inflammation and fibrosis status before surgery, but not the changes of connexins during surgery, were associated with the occurrence of post-CABG AF.

Late dialysis rate for coronary artery bypass grafting patients with moderate-to-severe renal impairment: comparison between off-pump and conventional method.

BACKGROUND: Whether off-pump coronary artery bypass grafting has a late renal protective advantage over conventional coronary arterial bypass grafting with cardiopulmonary bypass use is controversial. METHODS: From 1997 to 2004, 2102 cases of isolated coronary arterial bypass grafting were collected and analyzed, 1116 (53%) in the cardiopulmonary bypass group and 986 (47%) in the off-pump coronary artery bypass grafting group. Cases were stratified by preoperative estimated glomerular filtration rate into three renal groups: 1012 (48%) in group 1, with glomerular filtration rates > or =60 ml/h, 864 (41%) in group 2, with glomerular filtration rates of 30-60 ml/h, and 226 (10.8%) in group 3, with glomerular filtration rates <30 ml/h, but without dialysis before surgery. RESULTS: The in-hospital mechanical renal replacement therapy rates were 2.0%, 4.6%, and 26.1%, respectively, for the three renal groups that underwent coronary artery bypass grafting with conventional cardiopulmonary bypass, and 1.1%, 3.4%, and 14.0%, respectively for the three renal groups that underwent off-pump coronary artery bypass grafting. After risk adjustment, cardiopulmonary bypass use did not show statistical significance for in-hospital mechanical renal replacement therapy (p=0.314, 0.524, 0.150, respectively, across renal groups 1-3). At the end of the 4-year follow-up period, 99.1%, 97.2%, and 78.6%, respectively, of patients were free of mechanical renal replacement therapy across the three renal groups (p=0.0097 between renal groups 1 and 2; p<0.001 between renal groups 2 and 3). Cox regression analysis for renal groups 2 and 3 revealed that cardiopulmonary bypass use was not a risk factor for mid-term mechanical renal replacement therapy (p=0.452), but preoperative glomerular filtration rate, hypercholesterolemia, insulin-requiring diabetes, young age at surgery, female gender, and in-hospital mechanical renal replacement therapy use were. CONCLUSION: Patient characteristics, rather than operative strategy of using off-pump or conventional coronary artery bypass grafting, influence the mid-term mechanical renal replacement therapy rate for patients with glomerular filtration rates <60 ml/min.