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Shimizu S, Sakamoto S, Horikawa R, Fukuda A, Uchida H, Takeda M, Yanagi Y, Irie R, Yoshioka T, Kasahara M. Longterm Outcomes of Living Donor Liver Transplantation for Glycogen Storage Disease Type 1b. Liver Transpl 2020; 26:57-67. [PMID: 31587472 DOI: 10.1002/lt.25649] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 09/03/2019] [Indexed: 02/07/2023]
Abstract
Glycogen storage disease (GSD) type 1b (Online Mendelian Inheritance in Man [OMIM] 232220) is an autosomal recessive inborn error of carbohydrate metabolism caused by defects in glucose-6-phosphate translocase. GSD1b patients have severe hypoglycemia with several clinical manifestations of hepatomegaly, obesity, a doll-like face, and neutropenia. Liver transplantation (LT) has been indicated for severe glucose intolerance, poor metabolic control (PMC), and poor growth (PG). We retrospectively reviewed 11 children with GSD1b who underwent living donor liver transplantation (LDLT) at the National Center for Child Health and Development in Tokyo, Japan. Between November 2005 and December 2018, 495 children underwent LDLT with an overall 10-year patient and graft survival of 90.6% and 88.9%, respectively. Of these, LT was indicated for 11 patients with GSD1b. All patients are doing well with the stabilization of glucose intolerance and decreased hospitalization for infectious complications. Demand for granulocyte colony-stimulating factor significantly decreased. However, although LT stabilized the blood glucose level, the platelet function was not improved. The posttransplant developmental quotient (DQ) remained similar to the pretransplant DQ without deterioration. LDLT is a feasible procedure for GSD1b patients with regard to the longterm prognosis. LT should be considered for patients with severe glucose intolerance to protect the cognitive function against hypoglycemic encephalopathy and to ameliorate PMC and PG.
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Affiliation(s)
- Seiichi Shimizu
- Organ Transplantation Center, National Center for Child Health and Development, Tokyo, Japan
| | - Seisuke Sakamoto
- Organ Transplantation Center, National Center for Child Health and Development, Tokyo, Japan
| | - Reiko Horikawa
- Department of Endocrinology and Metabolism, National Center for Child Health and Development, Tokyo, Japan
| | - Akinari Fukuda
- Organ Transplantation Center, National Center for Child Health and Development, Tokyo, Japan
| | - Hajime Uchida
- Organ Transplantation Center, National Center for Child Health and Development, Tokyo, Japan
| | - Masahiro Takeda
- Organ Transplantation Center, National Center for Child Health and Development, Tokyo, Japan
| | - Yusuke Yanagi
- Organ Transplantation Center, National Center for Child Health and Development, Tokyo, Japan
| | - Rie Irie
- Department of Pathology, National Center for Child Health and Development, Tokyo, Japan
| | - Takako Yoshioka
- Department of Pathology, National Center for Child Health and Development, Tokyo, Japan
| | - Mureo Kasahara
- Organ Transplantation Center, National Center for Child Health and Development, Tokyo, Japan
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Niijima S, Ohmori T, Kario K. Differential impact of diabetes mellitus on antiplatelet effects of prasugrel and clopidogrel. Thromb J 2018; 16:5. [PMID: 29568240 PMCID: PMC5853094 DOI: 10.1186/s12959-017-0159-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 12/29/2017] [Indexed: 12/11/2022] Open
Abstract
Background Although prasugrel exerts stronger antiplatelet effects compared with clopidogrel, the factors affecting platelet reactivity under prasugrel have not been fully determined. This study aimed to find the novel mechanistic differences between two thienopyridines and identify the factor that influence platelet reactivity to each drug. Methods Forty patients with stable angina who underwent elective percutaneous coronary intervention were randomly assigned to receive either prasugrel (20 mg) or clopidogrel (300 mg) as a loading dose. Platelet function (light transmission, laser light scattering, and vasodilator-stimulated phosphoprotein phosphorylation) and plasma active metabolite levels were measured after the loading dose. Results Prasugrel consistently inhibited adenosine diphosphate receptor P2Y12 signalling to abolish amplification of platelet aggregation. Prasugrel abolished even small platelet aggregates composed of less than 100 platelets. On the other hand, clopidogrel inhibited large aggregates but increased small and medium platelet aggregates. Diabetes was the only independent variable for determining antiplatelet effects and active metabolite concentration of prasugrel, but not clopidogrel. Sleep-disordered breathing was significantly correlated with platelet reactivity in patients who had clopidogrel. Conclusions Prasugrel efficiently abolishes residual P2Y12 signalling that causes small platelet aggregates, but these small aggregates are not inhibited by clopidogrel. Considering the differential effect of diabetes on antiplatelet effects between these two drugs, the pharmacokinetics of prasugrel, other than cytochrome P450 metabolism, might be affected by diabetes. Trial registration UMIN-CTR UMIN000017624, retrospectively registered 21 May 2015.
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Affiliation(s)
- Satoshi Niijima
- 1Division of Cardiovascular Medicine, Department of Medicine, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498 Japan
| | - Tsukasa Ohmori
- 2Department of Biochemistry, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498 Japan
| | - Kazuomi Kario
- 1Division of Cardiovascular Medicine, Department of Medicine, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498 Japan
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Coupling factor 6 enhances the spontaneous microaggregation of platelets by decreasing cytosolic cAMP irrespective of antiplatelet therapy. Hypertens Res 2013; 36:520-7. [PMID: 23388886 DOI: 10.1038/hr.2012.231] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The spontaneous microaggregation of platelets (SMAPs) is a marker for the prognosis of patients with cardiovascular diseases. Coupling factor 6 (CF6) binds to the plasma membrane ATP synthase and functions as a pro-atherogenic molecule in the cardiovascular system. However, the role of CF6 in SMAPs and stroke remains unknown. In 650 consecutive patients, including those with acute-onset stroke, and 20 control subjects, platelet-rich plasma (PRP) was obtained, and SMAP was measured using a laser light-scattering aggregometer. The cytosolic cyclic adenosine monophosphate (cAMP) concentration in platelets was measured using an enzyme-linked immunosorbent assay. CF6 increased SMAPs in patients and control subjects to a similar degree by binding to the α- and β-subunits of ATP synthase and inducing intracellular acidosis. It was abolished by PRP pretreatment with antibodies against CF6, and the α- or β-subunit of the plasma membrane ATP synthase, and the ATP synthase inhibitor efrapeptin. CF6 increased SMAPs in patient groups with and without antiplatelet therapy to a similar degree, and no difference was found among the subgroups taking aspirin, thienopyridine or cilostazol. The cytosolic cAMP concentration in platelets was decreased by CF6 in the presence of the direct adenylate cyclase activator forskolin. Pretreatment of PRP with the Gs activator cholera toxin blocked the decrease, whereas the Gi inactivator pertussis toxin and cilostazol had no influence. The CF6-induced acceleration of SMAPs was suppressed by cholera toxin but not by cilostazol or pertussis toxin. CF6 enhanced SMAPs by decreasing cytosolic cAMP. Because it was observed irrespective of antiplatelet agents, CF6 appears to be a novel target for antiplatelet therapy.
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Kajiwara I, Soejima H, Miyamoto S, Ogawa H. Effects of additional treatment of sarpogrelate to aspirin therapy on platelet aggregation and plasma plasminogen activator inhibitor activity in patients with stable effort angina. Thromb Res 2011; 128:547-51. [DOI: 10.1016/j.thromres.2011.06.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Revised: 06/02/2011] [Accepted: 06/06/2011] [Indexed: 10/17/2022]
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Konya H, Hasegawa Y, Hamaguchi T, Satani K, Umehara A, Katsuno T, Ishikawa T, Miuchi M, Kohri K, Suehiro A, Kakishita E, Miyagawa JI, Namba M. Effects of gliclazide on platelet aggregation and the plasminogen activator inhibitor type 1 level in patients with type 2 diabetes mellitus. Metabolism 2010; 59:1294-9. [PMID: 20070990 DOI: 10.1016/j.metabol.2009.12.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2009] [Revised: 11/27/2009] [Accepted: 12/01/2009] [Indexed: 10/20/2022]
Abstract
Vascular complications are a common factor determining morbidity and mortality of diabetic patients. In vitro studies have revealed that gliclazide has antiplatelet activities. To clinically assess this action, we measured the effects of gliclazide on platelet activities and abnormal fibrinolysis in patients with type 2 diabetes mellitus. We studied 14 patients aged 38 to 72 years (9 men and 5 women) with type 2 diabetes mellitus who have been treated with glibenclamide in our hospital for more than 6 months. We switched from glibenclamide to gliclazide using the average ratio of the respective doses, 2.5 vs 40 mg. We titrated the dose of gliclazide to keep the glycemic control at the same level as the previous (glibenclamide) treatment. We measured 10 micromol/L serotonin-induced or 0.5 micromol/L adenosine diphosphate (ADP)-induced platelet aggregate formation by particle counting using light scattering at baseline and up to 6 months after the switch. After switching to gliclazide, platelet aggregate formation induced by serotonin was significantly reduced (P < .05, compared with the levels observed after glibenclamide treatment). The body mass index, fasting plasma glucose, immunoreactive insulin, homeostasis model assessment of insulin resistance, hemoglobin A(1c) (HbA(1c)), total cholesterol, triglycerides, high-density lipoprotein cholesterol, prothrombin time, activated partial thromboplastin time, fibrinogen, thrombin-antithrombin III complex, plasmin-alpha2-plasmin inhibitor complex, and plasma plasminogen activator inhibitor type 1 (PAI-1) were not changed. In the group with improved HbA(1c) (n = 5), ADP-induced platelet aggregate formation and plasma PAI-1 level were significantly reduced (P < .05, compared with the group with aggravated HbA(1c), n = 9). Multiple regression analysis showed that percentage change of ADP-induced platelet aggregate formation (standardized beta = 0.540, P < .05) was independently associated with percentage change of plasma PAI-1 level in addition to percentage change of HbA(1c) (standardized beta = 0.657, P < .05) (R = 0.939, P < .05) after switching to gliclazide. The other independent variants, like the final dose of gliclazide, homeostasis model assessment of insulin resistance, percentage change of prothrombin time, activated partial thromboplastin time, and total cholesterol, were not significantly associated with the percentage change of plasma PAI-1 level. These results indicate that gliclazide inhibits platelet aggregation via the serotonin pathway, independently of the metabolic control per se. Furthermore, in the patients with improved glycemic control, gliclazide could inhibit ADP-induced platelet aggregation and reduce PAI-I level. Taken together, the results show that gliclazide may be more useful for the prevention of diabetic vascular complications than glibenclamide.
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Affiliation(s)
- Hiroyuki Konya
- Division of Diabetes and Metabolism, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Hyogo 663-8501, Japan.
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The impact of platelet function or C-reactive protein, on cardiovascular events after an acute myocardial infarction. Thromb J 2009; 7:12. [PMID: 19583836 PMCID: PMC2715384 DOI: 10.1186/1477-9560-7-12] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2009] [Accepted: 07/07/2009] [Indexed: 01/09/2023] Open
Abstract
Background Recurrent cardiovascular events following acute myocardial infarction (AMI) are common. The purpose of this study was to evaluate the impact of platelet aggregation, PFA-100 closure times and peak C-reactive protein (CRP), respectively, on the occurrence of death, myocardial infarction and ischemic cerebral events after an AMI. Furthermore, to examine the relationship between the platelet function tests and peak CRP. Methods Three hundred and thirty-four patients with AMI were included in the study. Platelet aggregation was analyzed by an aggregometer using laser light (PA-200). The state of high residual platelet reactivity was defined as normal closure times (PFA-100) during treatment with aspirin. Results The fourth quartile of peak CRP was associated with poorer outcome as compared to the first quartile in a multivariate Cox-regression analysis, with a hazard ratio of 2.0 (95% CI 1.1–3.7) for the occurrence of death, myocardial infarction and ischemic cerebral events. The fourth quartile of peak CRP (>64.6 mg/l) was associated with platelet aggregation (p < 0.001, adjusted R2 = 0.13) and high residual platelet reactivity, in a multivariate model, with an odds ratio of 2.9 (CI 95% 1.3–6.8), as compared to the first quartile. Neither the highest quartile of platelet aggregation nor the state of high residual platelet reactivity predicted new cardiovascular events. Conclusion In patients with myocardial infarction, measured peak CRP is associated with new cardiovascular events. Despite an association with peak CRP neither more pronounced platelet aggregation nor PFA-100 closure times independently predict new cardiovascular events.
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Karlsson F, Modica A, Mooe T. Association of level of kidney function and platelet aggregation in acute myocardial infarction. Am J Kidney Dis 2009; 54:262-9. [PMID: 19560852 DOI: 10.1053/j.ajkd.2009.04.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Accepted: 04/03/2009] [Indexed: 11/11/2022]
Abstract
BACKGROUND Decreased kidney function has been established as an important risk factor in patients presenting with acute coronary syndrome. In acute coronary syndrome, increased platelet aggregation is associated with vascular complications. The aim of this study is to examine whether decreased kidney function is associated with altered platelet function in patients presenting with acute myocardial infarction. STUDY DESIGN Prospective cohort. SETTING & PARTICIPANTS 413 patients presenting with acute myocardial infarction admitted to the cardiac intensive care unit at Ostersund Hospital, Ostersund, Sweden. PREDICTORS Glomerular filtration rate less than 60 mL/min/1.73 m(2) estimated from serum cystatin C level, comorbidity, medications, and markers of inflammation and hemostasis. OUTCOMES & MEASUREMENTS Platelet aggregation was assessed by measuring the formation of small platelet aggregates (SPAs) by using a laser light scattering method. A greater SPA level indicates greater platelet aggregation. Platelet aggregation analysis was performed on days 1, 2, 3, and 5 in-hospital. RESULTS We observed a significant increase in platelet aggregation during the first 3 days in the hospital regardless of kidney function (P < 0.001). Platelet aggregation was more pronounced in patients with estimated glomerular filtration rate less than 60 mL/min/1.73 m(2) on day 2 (SPA count, 65,000 versus 47,000; P = 0.01) and day 3 (SPA count, 77,000 versus 52,000; P = 0.02). In a multiple linear regression analysis, decreased kidney function was no longer significantly associated with increased platelet aggregation. Older age, greater plasma fibrinogen level, and diabetes mellitus were associated with increased platelet aggregation in the multivariable model. LIMITATIONS During the study period, 78 patients presenting with acute myocardial infarction were not eligible for inclusion. Differences in treatment with antiplatelet medication between the 2 groups might have affected our findings. CONCLUSIONS Platelet aggregation increases during the first days after acute myocardial infarction regardless of kidney function. There is no difference in platelet aggregation in patients according to level of kidney function.
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Affiliation(s)
- Fredrik Karlsson
- Department of Internal Medicine, Section of Cardiology, Ostersund Hospital, Ostersund, Sweden.
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Modica A, Karlsson F, Mooe T. Platelet aggregation and aspirin non-responsiveness increase when an acute coronary syndrome is complicated by an infection. J Thromb Haemost 2007; 5:507-11. [PMID: 17319905 DOI: 10.1111/j.1538-7836.2007.02378.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND Epidemiologic studies have shown that there is an association between acute respiratory infection and acute coronary syndrome. The aim of this study was to analyze the thrombotic risk, assessed by platelet aggregation and aspirin non-responsiveness, in patients with an acute coronary syndrome complicated by an infection. METHODS Patients with an acute coronary syndrome who were admitted to the intensive care unit and hospitalized for at least 3 days in 2002 and 2003 were eligible for the study. Three hundred and fifty-eight patients were included, of whom 66 had an infection during their hospital stay. Platelet aggregation was analyzed by an aggregometer using laser light (PA-200, laser light scattering). Aspirin non-responsiveness was defined as a closure time of RESULTS Platelet aggregation was more pronounced during an infectious complication (P < 0.001). The subgroups of patients with persistent fever, urinary tract infection, and pneumonia all had a higher level of aggregates than the group of patients without an infection (P = 0.007, P = 0.04, and P = 0.01, respectively). Aspirin non-responsiveness was more frequent in the group of subjects with pneumonia compared with those without an infection, 90% vs. 46% (P = 0.006). The CRP levels were independently associated with platelet aggregation and aspirin non-responsiveness (P < 0.001, P < 0.001, respectively). CONCLUSION An infectious complication during the course of an acute coronary syndrome leads to more pronounced platelet aggregation. Aspirin non-responsiveness is more frequent in severe infections, such as pneumonia. CRP is an independent predictor of platelet aggregation and aspirin non-responsiveness in the setting of an acute coronary syndrome.
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Affiliation(s)
- A Modica
- Department of Internal Medicine, Section of Cardiology, Ostersund Hospital, Ostersund, Sweden.
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Koda M, Banno Y, Naganawa T. Effect of neutrophil adhesion on the size of aggregates formed by agonist-activated platelets. Platelets 2006; 16:482-91. [PMID: 16287615 DOI: 10.1080/09537100500215455] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
In this study we have investigated the effect of human neutrophil on agonist-induced platelet aggregation by using the laser-light scattering method that can detect a two-phase process, formation of small aggregates followed by large aggregate formation. When nonstimulated neutrophils were added to agonist-stimulated platelet-rich plasma (PRP), the large platelet aggregates were decreased and the small ones were increased by using either collagen, thrombin or ADP as agonist. Scanning-electron microscopic observation showed marked adhesion of neutrophil to aggregated platelets. The supernatant from neutrophils cell lysate (neutrophil supernatant) showed inhibitory effect similar to that with intact neutrophils, suggesting that the inhibitory effect by neutrophils was due to soluble component(s) including proteases released from neutrophils adhered to activated platelets. We have examined the effect of inhibition of a major released protease, elastase. The addition of its potent inhibitor elafin to intact neutrophils or the neutrophil supernatant changed their antiaggregating activity. The treatment of platelets with genistein, an inhibitor of protein tyrosine kinase, decreased agonist-induced large aggregates and increased small ones, suggesting that certain protein tyrosine kinase would be involved in the transition from small to large platelet aggregates. It was also shown that the tyrosine phosphorylation induced by agonist stimulation of several high molecular-weight proteins of platelets was inhibited by coincubation with neutrophils, concurrent with increases in smaller phosphorylated proteins. In washed platelets, coincubation with neutrophils resulted in reduced formation of large aggregates when stimulated with collagen or thrombin and repressed agonist-induced activation of tyrosine protein kinases (Syk, Lyn, Src, and Pyk2), but not thrombin-induced ERK and p38 MAP kinase. These results suggest that the cleavage of platelet membrane glycoproteins at least in part by elastase which was released from neutrophils, is involved in the inhibition of the transition from small to large platelet aggregates.
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Affiliation(s)
- Masahiro Koda
- Department of Cell Signaling, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu, Japan.
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Yamamoto T, Kamei M, Yokoi N, Yasuhara T, Tei M, Kinoshita S. Comparative effect of antiplatelet therapy in retinal vein occlusion evaluated by the particle-counting method using light scattering. Am J Ophthalmol 2004; 138:809-17. [PMID: 15531317 DOI: 10.1016/j.ajo.2004.06.058] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/16/2004] [Indexed: 11/22/2022]
Abstract
PURPOSE To evaluate platelet aggregation in patients with retinal vein occlusion (RVO) by the light-scattering method and compare the effects of three antiplatelet drugs on aggregate formation. DESIGN Prospective, nonrandomized, interventional clinical trial. METHODS (1) Platelet aggregation was measured in 42 patients with untreated branch RVO (BRVO), 26 patients with central RVO (CRVO), and 30 healthy control subjects using a light-scattering platelet aggregometer. Platelet aggregates were classified as small, medium, and large according to light intensity. Total light intensities of each aggregate size were compared between BRVO, CRVO, and control subjects. (2) In 33 patients with RVO, platelet aggregation before and 2 weeks after the administration of ticlopidine, beraprost, or aspirin were compared. RESULTS (1) There was a statistically significant difference (P = 0.0073) between the control subjects (8.3 x 10(6) a.u.) and CRVO patients (22.9 x 10(6) a.u.) with respect to small aggregates. There was no statistically significant difference with respect to medium and large aggregate formation between the control subjects and either patient group. (2) Compared with aggregates formed in the absence of antiplatelet drugs, ticlopidine significantly inhibited only the formation of small aggregates and beraprost that of all sizes; aspirin did not significantly inhibit the formation of any aggregate sizes. CONCLUSIONS Increase in small platelet aggregates may be attributable to RVO pathogenesis. Beraprost and ticlopidine appear to inhibit small aggregate formation in RVO patients and may represent effective antiplatelet treatments. The light-scattering method is useful to investigate the pathogenesis of RVO and the effects of antiplatelet drugs.
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Affiliation(s)
- Takami Yamamoto
- Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
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Shimizu M, Kanazawa K, Matsuda Y, Takai E, Iwai C, Miyamoto Y, Hashimoto M, Akita H, Yokoyama M. Serotonin-2A receptor gene polymorphisms are associated with serotonin-induced platelet aggregation. Thromb Res 2004; 112:137-42. [PMID: 14967409 DOI: 10.1016/j.thromres.2003.12.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2003] [Revised: 11/29/2003] [Accepted: 12/02/2003] [Indexed: 11/19/2022]
Affiliation(s)
- Masakatsu Shimizu
- Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
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Miyaji R, Sakai M, Urano H, Nakata K, Sakamoto H, Shirahata A. Decreased platelet aggregation of platelet concentrate during storage recovers in the body after transfusion. Transfusion 2004; 44:891-9. [PMID: 15157257 DOI: 10.1111/j.1537-2995.2004.03214.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Previous reports have shown that storage decrease the ability of PLTs to aggregate in the form of PLT concentrate (PC). Nevertheless, there are few reports that have studied the PLT function in blood samples obtained from recipients after PLT transfusion. In this study, this issue was addressed by examining the ability of PLTs to aggregate after being transfused into the blood stream. STUDY DESIGN AND METHODS PC was transfused to the patients with extremely low PLT counts resulting from chemotherapy. The maximum extent of PLT aggregation and size of the aggregates were compared between PLT in stored PC before transfusion with the PLT-rich plasma (PRP) from the recipients after transfusion and with PRP from patients with moderate decrease in PLT counts after chemotherapy. RESULTS The maximum extent of PLT aggregation was significantly higher in PRP collected from the patients after transfusion compared to the extent obtained before transfusion. There were no significant differences in the maximum extents of PLT aggregation between the PRP collected from the recipients after PC transfusion and, in the same patients, when PLT counts were moderately low. CONCLUSION These results suggest that the observed decreased in PLT aggregation after storage can improve in the body after transfusion, and transfused PLTs have similar aggregation ability compared to the PLTs derived from the patient.
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Affiliation(s)
- Ryosuke Miyaji
- Department of Pediatrics and Transfusion Medicine, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
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Nakano H, Oka H, Matsuda T, Ooka S, Suzuki N, Hayashi J, Ishida S, Suzuki T, Hirota K, Ozaki S. Spontaneous platelet aggregation in patients with Behçet's disease by using laser-light scattering aggregometer. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 528:437-41. [PMID: 12918740 DOI: 10.1007/0-306-48382-3_89] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Affiliation(s)
- H Nakano
- Department of Internal Medicine, St Marianna University School of Medicine, Kawasaki, Japan
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Taki M, Kobayashi M, Ohi C, Shimizu H, Goto K, Aso K, Murano K. Spontaneous platelet aggregation in Kawasaki disease using the particle counting method. Pediatr Int 2003; 45:649-52. [PMID: 14651534 DOI: 10.1111/j.1442-200x.2003.01810.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Platelet aggregation is generally measured by the optical density method. This method is not very sensitive in detecting platelet activation because of the poor correlation between the formation of platelet aggregates and light transmission, and inability to detect small platelet aggregates. Recently, a new method was developed that detects small platelet aggregates formed in the early phase of platelet aggregation by means of a particle counting technique using light scattering. METHODS The present study used the particle counting method to measure spontaneous platelet aggregation (SPA) produced by agitation with a stirrer bar without agonists in patients with Kawasaki disease (KD) and children's thrombotic disease, and compared the results with the conventional optical density method. RESULTS Using the particle counting method, significantly higher SPA rates were found before treatment than in healthy adults and at the other stages of treatment. A similar tendency was noted with the optical density method; however, the positive rate of SPA was significantly higher with the particle counting method in each stage except the second stage, which was the period from the start of gamma-globulin therapy to 20 days. CONCLUSION These results indicate that enhanced platelet aggregation is noted at a high frequency before treatment of KD and that the particle counting method is superior to the optical density method in detecting enhanced platelet aggregation.
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Affiliation(s)
- Masashi Taki
- Department of Pediatrics, St. Marianna University School of Medicine, Kawasaki, Kanagawa, Japan.
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Miyamoto S, Sakamoto T, Soejima H, Shimomura H, Kajiwara I, Kojima S, Hokamaki J, Sugiyama S, Yoshimura M, Ozaki Y, Nakamura H, Yodoi J, Ogawa H. Plasma thioredoxin levels and platelet aggregability in patients with acute myocardial infarction. Am Heart J 2003; 146:465-71. [PMID: 12947364 DOI: 10.1016/s0002-8703(03)00311-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND Oxidative stress is thought to play an important role in atherosclerotic vascular disease. Recently, it has become possible to quantitatively measure thioredoxin, a marker of oxidative stress in human plasma. A platelet aggregometer that uses laser-light scattering enables minimal changes in platelet aggregability to be monitored; however, the relationship between oxidative stress and platelet aggregability in vivo is not well understood. METHODS We investigated plasma thioredoxin levels and platelet aggregability, in particular small platelet aggregates, in 45 patients with acute myocardial infarction (AMI); we compared the results with 33 patients with stable exertional angina (SEA) and 30 patients with chest pain syndrome (CPS). RESULTS The plasma thioredoxin levels and the degree of small platelet aggregates were higher in the AMI group than in the SEA and the CPS groups: in the AMI group, at 4 weeks after admission, both of those parameters were significantly decreased (P <.01), but they were still higher (P <.05) than in the SEA or the CPS group. There was a significant positive correlation between small platelet aggregates and plasma thioredoxin levels (rho = 0.354, P =.0002). We divided the AMI patients into 2 groups according to the 75 percentile of plasma thioredoxin levels on admission. At the chronic phase, the left ventricular ejection fraction was significantly higher in the lower thioredoxin group than in the higher thioredoxin group. CONCLUSIONS We showed that plasma thioredoxin levels and platelet aggregability increased concomitantly in patients with AMI. In these patients, increased plasma thioredoxin was associated with platelet hyperaggregability and lower left ventricular ejection fraction.
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Affiliation(s)
- Shinzo Miyamoto
- Department of Cardiovascular Medicine, Kumamoto University School of Medicine, Kumamoto, Japan
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Abela GS, Huang R, Ma H, Prieto AR, Lei M, Schmaier AH, Schwartz KA, Davis JM. Laser-light scattering, a new method for continuous monitoring of platelet activation in circulating fluid. THE JOURNAL OF LABORATORY AND CLINICAL MEDICINE 2003; 141:50-7. [PMID: 12518168 DOI: 10.1067/mlc.2003.4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
We evaluated a novel technique of laser-light scattering (LLS) to detect platelet-volume changes continuously, reflecting platelet aggregation in circulating fluid. Carotid arteries from 20 dogs were mounted in a dual perfusion chamber. Balloon angioplasty (BA) was performed and arteries perfused with platelet-rich plasma (PRP). A He-Ne laser beam was passed through cuvettes connected to tubing draining the arteries. From the angle of incidence, the average volume of aggregates was measured by the ratio of scattering light at 1 to 5 degrees' spread on the diode array of a multichannel analyzer. Platelet volume varied linearly with the scattered light ratio at 1 to 5 degrees (y = -24.2 + 27.6 x [y = particle size, microm(3); x = scattered light ratio at 1/5 degrees]). For comparison, we used an electronic particle counter (Coulter counter) to measure platelet volume. P-selectin expression was measured to confirm platelet activation. Comparing 10 uninjured and 10 BA-injured arteries, we found that platelet volume as measured with LLS increased from 21.6 +/- 4.1 to 52.1 +/- 12.5 microm(3) (P < .003); as measured with the Coulter counter, it increased from 29.9 +/- 2.4 to 62.3 +/- 7.0 microm(3) (P < .005). Six BA-injured arteries perfused with PRP and aspirin (0.2 mg/mL) were compared with six arteries treated with BA alone. The aspirin decreased platelet volume as measured with LLS from 56.2 +/- 11.8 to 40.2 +/- 12.7 microm(3) (P < .01); the Coulter counter revealed a decrease from 51.9 +/- 18.5 to 38.8 +/- 14.2 microm(3) (P < .001). Coulter counter and LLS results were correlated: r = 0.74, P < .05. The peak of P-selectin expression coincided with peak platelet volume. These data demonstrate that increases in circulating-platelet size stimulated by endovascular injury can be reliably and continuously monitored with the use of LLS.
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Affiliation(s)
- George S Abela
- Division of Cardiology, Department of Medicine, Michigan State University, East Lansing 48824, USA.
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17
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Hasegawa Y, Suehiro A, Higasa S, Namba M, Kakishita E. Enhancing effect of advanced glycation end products on serotonin-induced platelet aggregation in patients with diabetes mellitus. Thromb Res 2002; 107:319-23. [PMID: 12565718 DOI: 10.1016/s0049-3848(02)00348-1] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Advanced glycation end products (AGEs) are thought to be responsible for some complications of diabetes mellitus (DM), including microangiopathy. Plasma serotonin is increased in diabetes mellitus patients, and this increase is related, at least in part, to platelet hyperfunction. In order to clarify the relationship between advanced glycation end products, serotonin, and thrombotic complications in diabetes mellitus patients, we examined the effect of advanced glycation end products on serotonin-induced platelet aggregation. In diabetic patients, although serotonin-induced platelet aggregation was enhanced with an increase in serum-advanced glycation end products, there was no correlation between platelet aggregation and either hemoglobin A1c or fasting blood sugar. To examine the direct effect of advanced glycation end products on platelet aggregation, we prepared advanced glycation end products by in vitro incubation of human albumin with glucose (250 mM) at 37 degrees C for 8 weeks. Serotonin-induced platelet aggregation was dose-dependently increased by advanced glycation end products. Adenosine diphosphate-induced platelet aggregation also was increased by advanced glycation end products, but this increment was diminished by addition of sarpogrelate, a selective serotonin receptor antagonist. These results suggest that advanced glycation end products enhance platelet aggregation through the serotonin receptor, and perhaps influencing the development of thrombotic complications in diabetic patients.
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Affiliation(s)
- Yoshikazu Hasegawa
- Department of Internal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan
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18
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Satoh K, Yatomi Y, Kubota F, Ozaki Y. Small aggregates of platelets can be detected sensitively by a flow cytometer equipped with an imaging device: mechanisms of epinephrine-induced aggregation and antiplatelet effects of beraprost. CYTOMETRY 2002; 48:194-201. [PMID: 12210143 DOI: 10.1002/cyto.10128] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Although cross-talks between platelets and other blood cells are important in vivo, laboratory platelet aggregation tests have been performed mainly with the use of platelet-rich plasma (PRP) as samples. Methods that enable an efficient and sensitive detection of platelet aggregates in whole blood are being developed. METHODS A flow cytometer equipped with an imaging device, the flow imaging cytometer 2 (FIC2), was used to detect platelet aggregates in whole blood. RESULTS The FIC2 provides a resolution that is high enough to differentiate platelet aggregates from single platelets or other blood cells. Epinephrine elicited platelet aggregate formation in hirudin plus argatroban-treated whole blood, but not in PRP. The reconstitution study revealed that a small amount of adenosine diphosphate (ADP) from erythrocytes may play an important role in epinephrine-induced platelet aggregation (in whole blood), through mediation of P2Y1 receptors. When the inhibitory effect of beraprost, an antiplatelet agent, on platelet aggregation was assessed, analysis of whole blood samples with FIC2 proved to be the most sensitive among the methods available. CONCLUSIONS FIC2 is a promising device for detection of platelet aggregates in whole blood, with wide basic and clinical applications.
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Affiliation(s)
- Kaneo Satoh
- Department of Laboratory Medicine, Yamanashi Medical University, Tamaho, Nakakoma, Yamanashi, Japan
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19
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Suehiro A, Sawada A, Hasegawa Y, Takatsuka H, Higasa S, Kakishita E. Enhancement by cyclosporine A and tacrolimus of serotonin-induced formation of small platelet aggregation. Bone Marrow Transplant 2002; 29:107-11. [PMID: 11850703 DOI: 10.1038/sj.bmt.1703335] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2001] [Accepted: 11/06/2001] [Indexed: 11/09/2022]
Abstract
Cyclosporine A (CsA) may increase the incidence of thrombotic events, but whether tacrolimus (Tc) has such effects is still unclear. The serotonergic system has been linked to the thrombotic effects of CsA, but a direct effect of CsA on serotonin-induced platelet aggregation has not been demonstrated because of methodological difficulties. We measured the effects of CsA and Tc on serotonin-induced platelet aggregate formation by particle counting using light scattering. CsA and Tc both enhanced serotonin-induced formation of small platelet aggregates, however, neither CsA nor Tc affected aggregation induced by high or low concentrations of ADP, with or without addition of a serotonin receptor antagonist. Both CsA and Tc enhance platelet aggregation induced via the serotonin pathway.
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Affiliation(s)
- A Suehiro
- Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
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Miyamoto S, Ogawa H, Sakamoto T, Soejima H, Takazoe K, Shimomura H, Kajiwara I, Yoshimura M, Kugiyama K, Nakamura S, Ozaki Y. Platelet hyperaggregability persists even after the improvement of increased blood coagulation and impaired fibrinolysis with the stabilization of symptoms in patients with unstable angina. Int J Cardiol 2001; 80:235-42. [PMID: 11578720 DOI: 10.1016/s0167-5273(01)00515-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Platelet aggregation, blood coagulation, and fibrinolysis play a pivotal role in the pathogenesis of unstable angina. METHODS Platelet aggregability was examined on admission and after 2 weeks of treatment in 22 patients with unstable angina, in particular with regard to small-sized platelet aggregates, plasma tissue factor (TF) antigen levels as a marker of blood coagulation, and plasma plasminogen activator inhibitor (PAI) activity levels as an indicator of fibrinolysis. We also examined the same parameters in 19 patients with stable exertional angina and 17 patients with chest pain syndrome. RESULTS The number of small-sized platelet aggregates increased more significantly in the unstable angina group than in the stable exertional angina and chest pain syndrome groups. In the unstable angina group, the number of small-sized platelet aggregates decreased significantly after 2 weeks of treatment, but was still higher than that in the stable exertional angina and chest pain syndrome groups. Plasma TF antigen and PAI activity were higher in the unstable angina group than in the stable exertional angina and chest pain syndrome groups. TF and PAI activity decreased to normal ranges after 2 weeks of treatment in the unstable angina group. There were significant positive correlations among the three parameters on admission. CONCLUSIONS It was demonstrated that small-sized platelet aggregates, plasma TF antigen and PAI activity levels increased concomitantly in the unstable angina group. While the blood coagulation and fibrinolytic parameters decreased after stabilization of the clinical symptoms, platelet hyperaggregability still persisted. These results suggest that continuous antiplatelet therapy is essential for the treatment of unstable angina.
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Affiliation(s)
- S Miyamoto
- Department of Cardiovascular Medicine, Kumamoto University School of Medicine, 1-1-1 Honjo, Kumamoto City 860-8556,, Japan
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Miyamoto S, Ogawa H, Soejima H, Takazoe K, Kajiwara I, Sakamoto T, Yoshimura M, Kugiyama K, Yasue H. Increased rate of formation of small-sized platelet aggregates in patients with acute coronary syndromes. JAPANESE CIRCULATION JOURNAL 2000; 64:647-52. [PMID: 10981847 DOI: 10.1253/jcj.64.647] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Coronary thrombosis has been implicated in the pathogenesis of acute coronary syndromes, and platelet activation plays a pivotal role in the pathogenesis of coronary thrombus. A new platelet aggregometer using a laserlight scattering beam was trialled for assessment of platelet aggregation. Platelet aggregability, especially small-sized platelet aggregates, was investigated on admission using the laser-light scattering method and again after treatment in 23 patients with acute coronary syndromes. The platelet aggregability in 14 patients with stable exertional angina and in 14 control subjects was also examined. On admission, the number of small- and medium-sized platelet aggregates in the acute coronary syndromes group was significantly greater than in the stable exertional angina group or control group. However, the number of large-sized platelet aggregates on admission was not increased in the acute coronary syndromes group. Furthermore, the number of small- and medium-sized platelet aggregates decreased significantly after treatment in the acute coronary syndromes group. The increased number of small-sized platelet aggregates may sensitively reflect attacks of thrombosis in patients suffering acute coronary syndromes.
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Affiliation(s)
- S Miyamoto
- Department of Cardiovascular Medicine, Kumamoto University School of Medicine, Japan
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22
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Matsuo T, Kario K. Does clinical significance exist in small platelet aggregates detected by the laser light scattering method? Thromb Res 2000; 99:109-10. [PMID: 11012375 DOI: 10.1016/s0049-3848(00)00211-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Yang L, Yatomi Y, Satoh K, Ozaki Y. Inhibitory effects of beraprost on platelet aggregation: comparative study utilizing two methods of aggregometry. Thromb Res 1999; 94:25-32. [PMID: 10213178 DOI: 10.1016/s0049-3848(98)00187-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We evaluated the inhibitory effects of beraprost, a stable prostacyclin analogue, on platelet aggregation, assessed by two methods of platelet aggregometry. The conventional aggregometry detects changes in light transmission (LT) of a platelet suspension, and a recently developed aggregometry based upon a particle counting principle detects light scattering (LS) generated by platelet aggregates. Since LS is more sensitive than LT in detecting platelet aggregates of small size, the minimal concentrations of agonists (ADP, epinephrine, collagen, and U46619) to induce detectable aggregate formation were consistently lower with LS (1/2 to 1/6) than with LT. The effects of beraprost were evaluated on platelet aggregation induced by the optimal concentrations of agonists thus determined for each sample. The IC50 values of beraprost on platelet aggregation, as assessed by LS, were 1/2 to 1/10 of those assessed by LT. In suppressing platelet aggregation assessed by LS, beraprost was especially potent with IC50 of 0.2-0.5 nM when platelets were activated by U46619, a thromboxane A2 analogue, or low concentrations of collagen which activates platelets through thromboxane A2 production. The IC50 values were 2-5 nM with ADP and epinephrine, which induce the formation of small aggregates independently of thromboxane A2 production. These findings suggest that LS can detect inhibitory effects of lower concentrations of antiplatelet agents, since it detects the formation of small aggregates induced by agonists in the lower concentration range than LT. It is also suggested that beraprost potently inhibits thromboxane A2-elicited initial signal transduction pathway, reflected by the formation of small aggregates.
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Affiliation(s)
- L Yang
- Department of Clinical and Laboratory Medicine, Yamanashi Medical University, Nakakoma, Japan
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24
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Serebruany VL, Gurbel PA. Effect of thrombolytic therapy on platelet expression and plasma concentration of PECAM-1 (CD31) in patients with acute myocardial infarction. Arterioscler Thromb Vasc Biol 1999; 19:153-8. [PMID: 9888878 DOI: 10.1161/01.atv.19.1.153] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Animal studies have shown that the administration of antibodies against platelet/endothelial cell adhesion molecule-1 (PECAM-1) before reperfusion can reduce infarct size. The purpose of the present study was to define the effects of thrombolytic therapy in acute myocardial infarction (AMI) patients on the platelet expression and plasma concentrations of PECAM-1 at prespecified time points after attempted reperfusion. The plasma concentration and platelet expression of PECAM-1 were determined in 23 AMI patients enrolled in the Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO-III) trial before thrombolysis and at 3, 6, 12, and 24 hours thereafter and compared with 22 healthy controls. At baseline, PECAM-1 was expressed significantly more on the platelet surface in the AMI patients than in controls (P=0.027) while soluble PECAM-1 plasma levels were almost identical between groups. There were no significant diurnal variations in both plasma and platelet PECAM-1 levels in controls. A significant decrease in platelet PECAM-1 expression was observed 3 hours after thrombolysis (P=0.03) compared with baseline, followed by a significant increase (P=0.004) in fluorescence intensity later at 24 hours after thrombolysis. Conversely, a significant increase in soluble PECAM-1 was observed 3 hours after thrombolysis (P=0.02), followed by a significant decrease later at 24 hours after attempted reperfusion (P=0.03). The expression of platelet-bound PECAM-1 is increased in AMI patients. Discordantly directed changes in soluble and platelet PECAM-1 after the first 24 hours after thrombolytic therapy may represent redistribution of the whole PECAM-1 pool. Further investigation of the possible role of PECAM-1 and the relationship between its soluble and platelet fractions in AMI are warranted.
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Affiliation(s)
- V L Serebruany
- Center for Thrombosis Research, Sinai Hospital of Baltimore, Baltimore, Md, USA.
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25
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Eto K, Takeshita S, Ochiai M, Ozaki Y, Sato T, Isshiki T. Platelet aggregation in acute coronary syndromes: use of a new aggregometer with laser light scattering to assess platelet aggregability. Cardiovasc Res 1998; 40:223-9. [PMID: 9876335 DOI: 10.1016/s0008-6363(98)00114-x] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE Platelet aggregation has been implicated in the pathogenesis of acute coronary syndromes. Small aggregates consisting of < or = 100 platelets cannot be quantified with a conventional aggregometer employing optical density. Using a recently developed aggregometer based on laser light scattering, we studied platelet aggregability in patients with acute coronary syndromes. METHODS Peripheral blood samples were obtained from 39 patients with acute myocardial infarction or unstable angina who had received no prior antiplatelet or anticoagulant therapy, to be assayed immediately using a PA-100 platelet aggregometer. Blood samples from 14 healthy volunteers were used as controls. RESULTS Spontaneous formation of platelet aggregates was observed only in patients with acute coronary syndromes. The size of these aggregates was small, consisting of < or = 100 platelets (primary aggregation). Agonist-induced aggregation consisted of two phases. In the first few minutes, the number of small aggregates increased markedly (primary aggregation), followed by an increase in larger aggregates (secondary aggregation). The EC50 of epinephrine for primary aggregation was nearly 50 times lower in acute coronary patients than in controls (P < 0.001), while the EC50 for secondary aggregation was only 2 times lower (P < 0.001). CONCLUSIONS Aggregometry using light scattering suggests that platelet hyperaggregability and hypersensitivity in acute coronary syndromes may occur in primary but not secondary aggregation.
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Affiliation(s)
- K Eto
- Department of Medicine (Cardiology), Teikyo University School of Medicine, Tokyo, Japan
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Abstract
AbstractNNKY5-5, an IgG monoclonal antibody directed against the von Willebrand factor-binding domain of glycoprotein (GP) Ibα, induced weak but irreversible aggregation (or association) of platelets in citrate-anticoagulated platelet-rich plasma. This phenomenon was defined as small aggregate formation (SAF ). Platelets in hirudin-anticoagulated plasma or washed platelets showed little response to NNKY5-5 alone, but the antibody potentiated aggregation induced by low concentrations of adenosine diphosphate or platelet-activating factor. NNKY5-5 did not induce granule release or intracellular Ca2+ mobilization. However, NNKY5-5 caused tyrosine phosphorylation of a 64-kD protein and activation of a tyrosine kinase, p72syk. An anti-FcγII receptor antibody had no effect on SAF, suggesting that NNKY5-5 activated platelets by interacting with glycoprotein Ib. Fab′ fragments of NNKY5-5 did not induce SAF, but potentiated aggregation induced by other agonists. The Fab′ fragment of NNKY5-5 induced the activation of p72syk, suggesting that such activation was independent of the FcγII receptor. Cross-linking of the receptor-bound Fab′ fragment of NNKY5-5 with a secondary antibody induced SAF. GRGDS peptide, chelation of extracellular Ca2+, and an anti-GPIIb/IIIa antibody inhibited NNKY5-5-induced SAF, but had no effect on 64-kD protein tyrosine phosphorylation or p72syk activations. Various inhibitors, including aspirin and protein kinase C, had no effect on SAF, protein tyrosine phosphorylation, or p72syk activation. In contrast, tyrphostin 47, a potent tyrosine kinase inhibitor, inhibited NNKY5-5–induced SAF as well as tyrosine phosphorylation and p72syk activation. Our findings suggest that binding of NNKY5-5 to GPIb potentiates platelet aggregation by facilitating the interaction between fibrinogen and GPIIb/IIIa through a mechanism associated with p72syk activation and tyrosine phosphorylation of a 64-kD protein.
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27
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Abstract
NNKY5-5, an IgG monoclonal antibody directed against the von Willebrand factor-binding domain of glycoprotein (GP) Ibα, induced weak but irreversible aggregation (or association) of platelets in citrate-anticoagulated platelet-rich plasma. This phenomenon was defined as small aggregate formation (SAF ). Platelets in hirudin-anticoagulated plasma or washed platelets showed little response to NNKY5-5 alone, but the antibody potentiated aggregation induced by low concentrations of adenosine diphosphate or platelet-activating factor. NNKY5-5 did not induce granule release or intracellular Ca2+ mobilization. However, NNKY5-5 caused tyrosine phosphorylation of a 64-kD protein and activation of a tyrosine kinase, p72syk. An anti-FcγII receptor antibody had no effect on SAF, suggesting that NNKY5-5 activated platelets by interacting with glycoprotein Ib. Fab′ fragments of NNKY5-5 did not induce SAF, but potentiated aggregation induced by other agonists. The Fab′ fragment of NNKY5-5 induced the activation of p72syk, suggesting that such activation was independent of the FcγII receptor. Cross-linking of the receptor-bound Fab′ fragment of NNKY5-5 with a secondary antibody induced SAF. GRGDS peptide, chelation of extracellular Ca2+, and an anti-GPIIb/IIIa antibody inhibited NNKY5-5-induced SAF, but had no effect on 64-kD protein tyrosine phosphorylation or p72syk activations. Various inhibitors, including aspirin and protein kinase C, had no effect on SAF, protein tyrosine phosphorylation, or p72syk activation. In contrast, tyrphostin 47, a potent tyrosine kinase inhibitor, inhibited NNKY5-5–induced SAF as well as tyrosine phosphorylation and p72syk activation. Our findings suggest that binding of NNKY5-5 to GPIb potentiates platelet aggregation by facilitating the interaction between fibrinogen and GPIIb/IIIa through a mechanism associated with p72syk activation and tyrosine phosphorylation of a 64-kD protein.
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28
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Qi R, Ozaki Y, Satoh K, Yang LB, Asazuma N, Yatomi Y, Kume S. Intracellular levels of cyclic AMP and cyclic GMP differentially modify platelet aggregate size in human platelets activated with epinephrine or ADP. J Cardiovasc Pharmacol 1996; 28:215-22. [PMID: 8856476 DOI: 10.1097/00005344-199608000-00006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We investigated the effects on human platelet aggregation of several agents that increase either intracellular cyclic AMP or cyclic GMP, using a platelet aggregometer that allows quantification of the size and number of platelet aggregates. During the initial phase of aggregation induced by epinephrine and ADP, small aggregates consisting of < 100 cells predominated; large aggregates formed later. Prostaglandin I2 (PGI2), which increases intracellular cyclic AMP, suppressed the formation of small as well as large aggregates induced by epinephrine, with ID50 values of 10.7 +/- 2.8 and 3.8 +/- 0.5 nM, respectively. ADP-induced formation of small and large aggregates was also inhibited by PGI2, with similar ID50 values. Dibutyryl cyclic AMP (db cyclic AMP), a cell-permeant form of cyclic AMP, also inhibited small and large aggregate formation induced by epinephrine or ADP, with ID50 values of 420-560 microM for small aggregates and 139-166 microM for large aggregates, respectively. On the other hand, nitroprusside, which increases intracellular cyclic GMP, inhibited only the formation of large aggregates, with an ID50 value of 454 +/- 191 nM for epinephrine-induced activation and of 2.1 +/- 0.6 microM for ADP-induced activation. Nitroprusside at 1 mM did not affect the formation of small aggregates induced by epinephrine, whereas that of large aggregates was completely blocked at 10 microM. 8-Bromo cyclic GMP (8-br cyclic GMP) also inhibited only the formation of large aggregates, with ID50 values of 140-170 microM, but not that of small aggregates induced by epinephrine and ADP. Milrinone, which increases the intracellular level of both cyclic AMP and cyclic GMP, suppressed the formation of small and large aggregates induced by epinephrine and ADP. These findings suggest that cyclic AMP and cyclic GMP differentially modify the size of aggregates formed during epinephrine or ADP activation.
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Affiliation(s)
- R Qi
- Department of Clinical and Laboratory Medicine, Yamanashi Medical University, Japan
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