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1.
Neurocrit Care ; 37(Suppl 1): 112-122, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-34855119

RESUMO

BACKGROUND: In ischemic stroke, cerebral autoregulation and neurovascular coupling may become impaired. The cerebral blood flow (CBF) response to spreading depolarization (SD) is governed by neurovascular coupling. SDs recur in the ischemic penumbra and reduce neuronal viability by the insufficiency of the CBF response. Autoregulatory failure and SD may coexist in acute brain injury. Here, we set out to explore the interplay between the impairment of cerebrovascular autoregulation, SD occurrence, and the evolution of the SD-coupled CBF response. METHODS: Incomplete global forebrain ischemia was created by bilateral common carotid artery occlusion in isoflurane-anesthetized rats, which induced ischemic SD (iSD). A subsequent SD was initiated 20-40 min later by transient anoxia SD (aSD), achieved by the withdrawal of oxygen from the anesthetic gas mixture for 4-5 min. SD occurrence was confirmed by the recording of direct current potential together with extracellular K+ concentration by intracortical microelectrodes. Changes in local CBF were acquired with laser Doppler flowmetry. Mean arterial blood pressure (MABP) was continuously measured via a catheter inserted into the left femoral artery. CBF and MABP were used to calculate an index of cerebrovascular autoregulation (rCBFx). In a representative imaging experiment, variation in transmembrane potential was visualized with a voltage-sensitive dye in the exposed parietal cortex, and CBF maps were generated with laser speckle contrast analysis. RESULTS: Ischemia induction and anoxia onset gave rise to iSD and aSD, respectively, albeit aSD occurred at a longer latency, and was superimposed on a gradual elevation of K+ concentration. iSD and aSD were accompanied by a transient drop of CBF (down to 11.9 ± 2.9 and 7.4 ± 3.6%, iSD and aSD), but distinctive features set the hypoperfusion transients apart. During iSD, rCBFx indicated intact autoregulation (rCBFx < 0.3). In contrast, aSD was superimposed on autoregulatory failure (rCBFx > 0.3) because CBF followed the decreasing MABP. CBF dropped 15-20 s after iSD, but the onset of hypoperfusion preceded aSD by almost 3 min. Taken together, the CBF response to iSD displayed typical features of spreading ischemia, whereas the transient CBF reduction with aSD appeared to be a passive decrease of CBF following the anoxia-related hypotension, leading to aSD. CONCLUSIONS: We propose that the dysfunction of cerebrovascular autoregulation that occurs simultaneously with hypotension transients poses a substantial risk of SD occurrence and is not a consequence of SD. Under such circumstances, the evolving SD is not accompanied by any recognizable CBF response, which indicates a severely damaged neurovascular coupling.


Assuntos
Circulação Cerebrovascular , Hipotensão , Animais , Córtex Cerebral , Circulação Cerebrovascular/fisiologia , Homeostase/fisiologia , Hipóxia , Isquemia , Ratos
2.
Biology (Basel) ; 9(12)2020 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-33322264

RESUMO

Ischemic stroke is a leading cause of death and disability worldwide. Yet, the effective therapy of focal cerebral ischemia has been an unresolved challenge. We propose here that ischemic tissue acidosis, a sensitive metabolic indicator of injury progression in cerebral ischemia, can be harnessed for the targeted delivery of neuroprotective agents. Ischemic tissue acidosis, which represents the accumulation of lactic acid in malperfused brain tissue is significantly exacerbated by the recurrence of spreading depolarizations. Deepening acidosis itself activates specific ion channels to cause neurotoxic cellular Ca2+ accumulation and cytotoxic edema. These processes are thought to contribute to the loss of the ischemic penumbra. The unique metabolic status of the ischemic penumbra has been exploited to identify the penumbra zone with imaging tools. Importantly, acidosis in the ischemic penumbra may also be used to guide therapeutic intervention. Agents with neuroprotective promise are suggested here to be delivered selectively to the ischemic penumbra with pH-responsive smart nanosystems. The administered nanoparticels release their cargo in acidic tissue environment, which reliably delineates sites at risk of injury. Therefore, tissue pH-targeted drug delivery is expected to enrich sites of ongoing injury with the therapeutical agent, without the risk of unfavorable off-target effects.

3.
Neurobiol Dis ; 137: 104780, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31991249

RESUMO

Spontaneous, recurrent spreading depolarizations (SD) are increasingly more appreciated as a pathomechanism behind ischemic brain injuries. Although the prostaglandin F2α - FP receptor signaling pathway has been proposed to contribute to neurodegeneration, it has remained unexplored whether FP receptors are implicated in SD or the coupled cerebral blood flow (CBF) response. We set out here to test the hypothesis that FP receptor blockade may achieve neuroprotection by the inhibition of SD. Global forebrain ischemia/reperfusion was induced in anesthetized rats by the bilateral occlusion and later release of the common carotid arteries. An FP receptor antagonist (AL-8810; 1 mg/bwkg) or its vehicle were administered via the femoral vein 10 min later. Two open craniotomies on the right parietal bone served the elicitation of SD with 1 M KCl, and the acquisition of local field potential. CBF was monitored with laser speckle contrast imaging over the thinned parietal bone. Apoptosis and microglia activation, as well as FP receptor localization were evaluated with immunohistochemistry. The data demonstrate that the antagonism of FP receptors suppressed SD in the ischemic rat cerebral cortex and reduced the duration of recurrent SDs by facilitating repolarization. In parallel, FP receptor antagonism improved perfusion in the ischemic cerebral cortex, and attenuated hypoemic CBF responses associated with SD. Further, FP receptor antagonism appeared to restrain apoptotic cell death related to SD recurrence. In summary, the antagonism of FP receptors (located at the neuro-vascular unit, neurons, astrocytes and microglia) emerges as a promising approach to inhibit the evolution of SDs in cerebral ischemia.


Assuntos
Isquemia Encefálica/tratamento farmacológico , Circulação Cerebrovascular/efeitos dos fármacos , Depressão Alastrante da Atividade Elétrica Cortical/efeitos dos fármacos , Dinoprosta/análogos & derivados , Animais , Isquemia Encefálica/fisiopatologia , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/fisiopatologia , Infarto Cerebral/tratamento farmacológico , Circulação Cerebrovascular/fisiologia , Depressão Alastrante da Atividade Elétrica Cortical/fisiologia , Dinoprosta/farmacologia , Masculino , Prosencéfalo/efeitos dos fármacos , Prosencéfalo/fisiopatologia , Prostaglandinas/farmacologia , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos
4.
Neuropharmacology ; 162: 107850, 2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31715193

RESUMO

Stroke is an important cause of mortality and disability. Treatment options are limited, therefore the progress in this regard is urgently needed. Nimodipine, an L-type voltage-gated calcium channel antagonist dilates cerebral arterioles, but its systemic administration may cause potential side effects. We have previously constructed chitosan nanoparticles as drug carriers, which release nimodipine in response to decreasing pH typical of cerebral ischemia. Here we have set out to evaluate this nanomedical approach to deliver nimodipine selectively to acidic ischemic brain tissue. After washing a nanoparticle suspension with or without nimodipine (100 µM) on the exposed brain surface of anesthetized rats (n = 18), both common carotid arteries were occluded to create forebrain ischemia. Spreading depolarizations (SDs) were elicited by 1M KCl to deepen the ischemic insult. Local field potential, cerebral blood flow (CBF) and tissue pH were recorded from the cerebral cortex. Microglia activation and neuronal survival were evaluated in brain sections by immunocytochemistry. Ischemia-induced tissue acidosis initiated nimodipine release from nanoparticles, confirmed by the significant elevation of baseline CBF (47.8 ±â€¯23.7 vs. 29.3 ±â€¯6.96%). Nimodipine shortened the duration of both SD itself (48.07 ±â€¯23.29 vs. 76.25 ±â€¯17.2 s), and the associated tissue acidosis (65.46 ±â€¯20.2 vs. 138.3 ±â€¯66.07 s), moreover it enhanced the SD-related hyperemia (48.15 ±â€¯42.04 vs. 17.29 ±â€¯11.03%). Chitosan nanoparticles did not activate microglia. The data support the concept that tissue acidosis linked to cerebral ischemia can be employed as a trigger for targeted drug delivery. Nimodipine-mediated vasodilation and SD inhibition can be achieved by pH-responsive chitosan nanoparticles applied directly to the brain surface.


Assuntos
Acidose/metabolismo , Isquemia Encefálica/metabolismo , Bloqueadores dos Canais de Cálcio/administração & dosagem , Quitosana/metabolismo , Microglia/efeitos dos fármacos , Nanopartículas/metabolismo , Nimodipina/administração & dosagem , Prosencéfalo/efeitos dos fármacos , Acidose/etiologia , Animais , Materiais Biocompatíveis , Isquemia Encefálica/complicações , Isquemia Encefálica/patologia , Artéria Carótida Primitiva , Sobrevivência Celular , Circulação Cerebrovascular , Depressão Alastrante da Atividade Elétrica Cortical/efeitos dos fármacos , Portadores de Fármacos , Sistemas de Liberação de Medicamentos , Concentração de Íons de Hidrogênio , Neurônios/efeitos dos fármacos , Neurônios/patologia , Prosencéfalo/irrigação sanguínea , Prosencéfalo/patologia , Ratos
5.
Orv Hetil ; 160(38): 1487-1494, 2019 Sep.
Artigo em Húngaro | MEDLINE | ID: mdl-31537095

RESUMO

Immune status was investigated in 186 patients with chronic lymphoid leukaemia between January 2012 and March 2015. Incidences of infections and mortality were analysed in patients who did not receive prophylactic immunoglobulin therapy. Immunoglobulin G (IgG) levels were normal (7-17.8 g/L) or decreased in 62.37% and 35.48% of patients, respectively. We measured high immunoglobulin levels only in a few cases (2.15%). Immunoglobulin levels became increasingly lower in more advanced disease stages (Rai stages). The number of infections was inversely proportional to that. Hypogammaglobulinaemia proved to be more important than disease progression in terms of the development of infections. The most common infections were upper respiratory tract (33.07%) and sepsis (18.90%). Two months after chemotherapy, initially normal immunoglobulin levels decreased by an average of 21%, and at the same time the incidence of infections increased. The most common cause of death was sepsis: 30% occurred at low immunoglobulin levels, while 20% at normal immunoglobulin levels. According to literature, prophylactic immunoglobulin treatment is indicated in patients with chronic lymphoid leukaemia and immunodeficiency for decreasing both morbidity and mortality. According to recommendations in literature, replacement treatment must be administered in severe or moderately severe recurrent bacterial infections. Immunoglobulin prophylaxis may be provided as low dose (10 g), fix dose (18 g) or individually customized higher dose (300-400 mg/kg body weight) treatment. According to recommendations, higher dose immunoglobulin prophylaxis, administered every three weeks on six occasions, is more efficient when customized. With this dose, infection-free condition may be achieved in 50% of patients. Orv Hetil. 2019; 160(38): 1487-1494.


Assuntos
Agamaglobulinemia/tratamento farmacológico , Agamaglobulinemia/mortalidade , Imunoglobulinas Intravenosas/uso terapêutico , Imunoglobulinas/administração & dosagem , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Sepse/mortalidade , Agamaglobulinemia/complicações , Relação Dose-Resposta a Droga , Feminino , Humanos , Hungria/epidemiologia , Imunoglobulina G/sangue , Imunoglobulinas Intravenosas/administração & dosagem , Controle de Infecções , Leucemia Linfocítica Crônica de Células B/complicações , Leucemia Linfocítica Crônica de Células B/mortalidade , Masculino , Sepse/diagnóstico , Resultado do Tratamento
6.
Br J Pharmacol ; 176(9): 1222-1234, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30737967

RESUMO

BACKGROUND AND PURPOSE: A new class of dihydropyridine derivatives, which act as co-inducers of heat shock protein but are devoid of calcium channel antagonist and vasodilator effects, has recently been developed with the purpose of selectively targeting neurodegeneration. Here, we evaluated the action of one of these novel compounds LA1011 on neurovascular coupling in the ischaemic rat cerebral cortex. As a reference, we applied nimodipine, a vasodilator dihydropyridine and well-known calcium channel antagonist. EXPERIMENTAL APPROACH: Rats were treated with LA1011 or nimodipine, either by chronic, systemic (LA1011), or acute, local administration (LA1011 and nimodipine). In the latter treatment group, global forebrain ischaemia was induced in half of the animals by bilateral common carotid artery occlusion under isoflurane anaesthesia. Functional hyperaemia in the somatosensory cortex was created by mechanical stimulation of the contralateral whisker pad under α-chloralose anaesthesia. Spreading depolarization (SD) events were elicited subsequently by 1 M KCl. Local field potential and cerebral blood flow (CBF) in the parietal somatosensory cortex were monitored by electrophysiology and laser Doppler flowmetry. KEY RESULTS: LA1011 did not alter CBF, but intensified SD, presumably indicating the co-induction of heat shock proteins, and, perhaps an anti-inflammatory effect. Nimodipine attenuated evoked potentials and SD. In addition to the elevation of baseline CBF, nimodipine augmented hyperaemia in response to both somatosensory stimulation and SD, particularly under ischaemia. CONCLUSIONS AND IMPLICATIONS: In contrast to the CBF improvement achieved with nimodipine, LA1011 seems not to have discernible cerebrovascular effects but may up-regulate the stress response.


Assuntos
Bloqueadores dos Canais de Cálcio/farmacologia , Circulação Cerebrovascular/efeitos dos fármacos , Di-Hidropiridinas/farmacologia , Córtex Somatossensorial/efeitos dos fármacos , Animais , Masculino , Ratos , Ratos Sprague-Dawley
7.
Blood Coagul Fibrinolysis ; 29(5): 435-441, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29782332

RESUMO

: The diagnosis of thrombophilia is a cost-consuming and time-consuming process, as each defect should be separately investigated. The Coagulation Inhibitor Potential (CIP) assay is a promising new global test, sensitive for most of the hereditary thrombophilias, developed for manual methodology. We adapt the original method to an optical coagulation analyser. By this automation, the test will be easier, faster and more precise, and it also allows carrying out 18 measurements simultaneously. The CIP assay was performed in 126 healthy subjects and 193 patients with different types of hereditary thrombophilia conditions. Detected with conventional laboratory tests high-risk thrombophilia was present in 70 patients: deficiencies of antithrombin (AT) (n = 12), protein C (PC) (n = 14), protein S (PS) (n = 6), homozygous factor V Leiden (FVL) mutation (n = 9) and combined types (n = 29). Low-risk thrombophilia was present in 123 patients: heterozygous FVL (n = 115) and FII G2010A mutation (n = 8). Significantly lower median CIP values were found for AT-,PC-, PS deficiencies, homozygous and heterozygous FVL mutations and combined thrombophilias (P < 0.01) as compared with healthy controls. There was no significant difference between the heterozygous FIIG20210A (P = 0.669) thrombophilia group and the healthy controls. The best performance of the test was achieved at the cut-off value of 90.0 U (area: 0.981) with 96% sensitivity and 92% specificity in the high-risk thrombophilia group estimated by receiver operating characteristic analysis. The new method seems to be appropriate and reliable for the detection of AT-, PC- and PS deficiencies, homozygous FVL mutation and also for combined deficiencies. The automated CIP test is insensitive to FII G2010A mutation.


Assuntos
Testes de Coagulação Sanguínea/métodos , Trombofilia/diagnóstico , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Trombofilia/sangue , Trombofilia/patologia
8.
Orv Hetil ; 158(41): 1615-1619, 2017 Oct.
Artigo em Húngaro | MEDLINE | ID: mdl-29025289

RESUMO

T-cell lymphoma is a poor prognostic hematological malignancy. The generally used - not sufficiently effective - induction chemotherapy should be improved with consolidative autologous hemopoetic stem cell transplantation. The authors describe the role, place and effectiveness of transplantation in this disorder. One hundred thirty three autologous stem cell transplantations were performed in the last 22 years in Hungary. Detailed results are available from the last 6 years. In this period 43 transplantations were carried out in 4 Hungarian centers. Carmustine-etoposide-cytosine arabinoside-melphalan (BEAM) conditioning regimen was used in 95%. The transplantation was done mainly in complete remission (84%), 1 year after transplantation 65% of patients were still in complete remission. Eleven patients died, 82% of them have progressive disease. Brentuximab vedotin has already proved the effectiveness, several other chemoterapeutics, monoclonal antibodies, kinase inhibitors are under investigation. In certain cases allogeneic stem cell transplantation has real indication among therapeutic options. Orv Hetil. 2017; 158(41): 1615-1619.


Assuntos
Transplante de Células-Tronco Hematopoéticas , Imunoconjugados/administração & dosagem , Linfoma de Células T/terapia , Brentuximab Vedotin , Quimioterapia de Consolidação , Humanos , Hungria , Indução de Remissão , Transplante Autólogo
9.
Neurobiol Aging ; 36(12): 3269-3277, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26346140

RESUMO

Spreading depolarizations (SDs) occur spontaneously in the brain after stroke, exacerbate ischemic injury, and thus emerge as a potential target of intervention. Aging predicts worse outcome from stroke; yet, the impact of age on SD evolution is not clear. Cerebral ischemia was induced by bilateral common carotid artery occlusion in young (8-9 weeks old, n = 8) and old (2 year olds, n = 6) anesthetized rats. Sham-operated animals of both age groups served as control (n = 12). Electrocorticogram, direct current potential, and cerebral blood flow (CBF) variations were acquired via a small craniotomy above the parietal cortex. SDs were elicited by KCl through a second craniotomy distal to the recording site. Ischemia and age delayed the recovery from SD. CBF decreased progressively during ischemia in the old animals selectively, and inverse neurovascular coupling with SD evolved in the old but not in the young ischemic group. We propose that (mal)adaptation of cerebrovascular function with aging impairs the SD-related CBF response, which is implicated in the intensified expansion of ischemic damage in the old brain.


Assuntos
Envelhecimento/patologia , Envelhecimento/fisiologia , Isquemia Encefálica/patologia , Isquemia Encefálica/fisiopatologia , Encéfalo/irrigação sanguínea , Encéfalo/patologia , Circulação Cerebrovascular/fisiologia , Animais , Eletrocorticografia , Masculino , Ratos Sprague-Dawley , Ratos Wistar
10.
Thromb Res ; 131(4): e183-7, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23481480

RESUMO

INTRODUCTION: Normal pregnancy is associated with hypercoagulable state. Elevated markers of coagulation and fibrinolytic system activation indicate increased thrombin activity and increased fibrinolysis following fibrin formation throughout pregnancy. These changes exceed the biological variability in most cases. Haemostatic reference intervals are generally based on samples from non-pregnant women. Thus, they may not be relevant to pregnant women, a problem that may hinder accurate diagnosis and treatment of haemostatic disorders during pregnancy. The aim of the study was to follow the changes of haemostatic parameters and to establish gestational age-specific reference intervals during normal pregnancy. MATERIALS AND METHODS: Blood samples of 83 pregnant women were collected at gestational weeks 16, 26 and 36. Fibrinogen, D-dimer, and C-Reactive Protein (CRP) were examined. Reference intervals were calculated for fibrinogen, D-dimer tests with two different methods (mean±2 SD or median and 2.5th and 97.5th percentiles with 90% confidence intervals). RESULTS: fibrinogen and D-dimer increased progressively throughout pregnancy. Mean fibrinogen levels were higher than the maximum of the conventional reference interval, already in the 16th week of pregnancy. D-dimer levels were at or above the conventional cutoff point (250ng/mL) throughout the pregnancy in 42% of pregnant women, while in the 36th week 98% of them displayed elevated D-dimer levels. CRP did not increase in normal pregnancy. CONCLUSIONS: There seems to be an emerging need to reconsider fibrinogen and D-dimer values from a different aspect in pregnancy compared to non-pregnant reference intervals. New reference ranges are suggested to be established in pregnancy.


Assuntos
Proteína C-Reativa/metabolismo , Produtos de Degradação da Fibrina e do Fibrinogênio/metabolismo , Fibrinogênio/metabolismo , Gravidez/sangue , Adulto , Biomarcadores/sangue , Estudos de Coortes , Feminino , Idade Gestacional , Humanos , Complicações na Gravidez/sangue
11.
Kidney Blood Press Res ; 34(3): 158-66, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21474963

RESUMO

BACKGROUND: Renal function is a major predictor of vascular function and cardiovascular diseases. Little information exists about the effect of specific renal diseases on vascular function in chronic kidney diseases (CKD). METHODS: One hundred and twenty patients (60 with IgA nephropathy, IgAN, and 60 with polycystic kidney disease, PKD) with CKD stages 1-4 were studied and compared. Pulse-wave velocity was measured by the digital volume pulse (DVP) method and stiffness index (SI(DVP)) was derived. RESULTS: All CKD (IgAN and PKD) patients had increased SI(DVP) compared to controls (10.39 vs. 8.87 ± 1.79 m/s, p = 0.008). PKD patients had increased SI(DVP) compared to IgAN and controls (11.14 ± 2.19, 9.66 ± 2.02 and 8.87 ± 1.79 m/s, respectively, p < 0.001). An inverse correlation was found between SI(DVP) and glomerular filtration rate in all CKD (IgAN and PKD) patients (p = 0.001) and in IgAN alone (p < 0.01), but not in PKD. With multivariate regression analysis, only age and 24-hour systolic blood pressure exerted independent effects on SI(DVP). CONCLUSIONS: Compared to controls, arterial stiffness was increased in CKD patients. However, arterial stiffening was more pronounced in PKD than in IgAN, suggesting that vascular function is not similarly altered in etiologically different CKD groups. The fact that blood pressure was an independent risk factor underscores a therapeutic opportunity.


Assuntos
Artérias/patologia , Glomerulonefrite por IGA/patologia , Doenças Renais Policísticas/patologia , Adulto , Pressão Sanguínea/fisiologia , Doença Crônica , Estudos de Coortes , Estudos Transversais , Feminino , Dedos/irrigação sanguínea , Taxa de Filtração Glomerular , Humanos , Nefropatias/patologia , Nefropatias/fisiopatologia , Testes de Função Renal , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Fotopletismografia , Doenças Renais Policísticas/fisiopatologia , Fluxo Sanguíneo Regional , Circulação Renal/fisiologia , Fatores de Risco
12.
Thromb J ; 8: 9, 2010 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-20465804

RESUMO

BACKGROUND: Poor platelet inhibition by aspirin or clopidogrel has been associated with adverse outcomes in patients with cardiovascular diseases. A reliable and facile assay to measure platelet inhibition after treatment with aspirin and a P2Y12 antagonist is lacking. Multiple electrode aggregometry (MEA), which is being increasingly used in clinical studies, is sensitive to platelet inhibition by aspirin and clopidogrel, but a critical evaluation of MEA monitoring of dual anti-platelet therapy with aspirin and P2Y12 antagonists is missing. DESIGN AND METHODS: By performing in vitro and ex vivo experiments, we evaluated in healthy subjects the feasibility of using MEA to monitor platelet inhibition of P2Y12 antagonists (clopidogrel in vivo, cangrelor in vitro) and aspirin (100 mg per day in vivo, and 1 mM or 5.4 mM in vitro) alone, and in combination. Statistical analyses were performed by the Mann-Whitney rank sum test, student' t-test, analysis of variance followed by the Holm-Sidak test, where appropriate. RESULTS: ADP-induced platelet aggregation in hirudin-anticoagulated blood was inhibited by 99.3 +/- 1.4% by in vitro addition of cangrelor (100 nM; p < 0.001) and by 64 +/- 35% by oral clopidogrel (600 mg) intake (p < 0.05; values are means +/- SD). Pre-incubation of blood with aspirin (1 mM) or oral aspirin intake (100 mg/day for 1 week) inhibited arachidonic acid (AA)-stimulated aggregation >95% and 100 +/- 3.2%, respectively (p < 0.01). Aspirin did not influence ADP-induced platelet aggregation, either in vitro or ex vivo. Oral intake of clopidogrel did not significantly reduce AA-induced aggregation, but P2Y12 blockade by cangrelor (100 nM) in vitro diminished AA-stimulated aggregation by 53 +/- 26% (p < 0.01). A feasibility study in healthy volunteers showed that dual anti-platelet drug intake (aspirin and clopidogrel) could be selectively monitored by MEA. CONCLUSIONS: Selective platelet inhibition by aspirin and P2Y12 antagonists alone and in combination can be rapidly measured by MEA. We suggest that dual anti-platelet therapy with these two types of anti-platelet drugs can be optimized individually by measuring platelet responsiveness to ADP and AA with MEA before and after drug intake.

13.
Thromb Haemost ; 97(3): 435-43, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17334511

RESUMO

Anti-platelet drugs are used to prevent intra-arterial thrombus formation after rupture of atherosclerotic plaques. Until now, the inhibitory effect of present and future anti-platelet drugs such as aspirin, ADP receptor P2Y(1)/P2Y(12) antagonists and glycoprotein (GP) Ibalpha inhibitors on the interaction of platelets with human plaques is not known. To study those effects we obtained human atherosclerotic plaques by surgical endarterectomy. Plaques induced maximal platelet aggregation in hirudinized platelet-rich plasma (PRP) and blood that was effectively inhibited by aspirin, the P2Y(1) antagonist MRS2179 and the P2Y(12) antagonist AR-C69931MX, but not by GPIbalpha blockade with the mAB 6B4. Inhibition of platelet aggregation by MRS2179 was 74 +/- 37% and 68 +/- 20%, by AR-C69931MX 94 +/- 7% and 80 +/- 6%, and by aspirin 88 +/- 19% and 64 +/- 28%, in PRP and blood, respectively (mean +/- SD; n = 6-12 with plaques from 6 patients). The combination of both ADP receptor antagonists completely inhibited plaque-induced platelet aggregation in hirudinized PRP and blood. Under arterial flow conditions (1,500s(-1)), blockade of platelet GPIbalpha resulted in a strong decrease of plaque-stimulated platelet adhesion/aggregate formation of 77 +/- 5% (mean +/- SD; n = 4). Furthermore, MRS2179, AR-C69931MX and their combination reduced plaque-dependent platelet aggregate formation by 35 +/- 14%, 32 +/- 13% and 58 +/- 12% (mean +/- SD; n = 5), respectively. Aspirin was without significant effect. In conclusion, a GPIbalpha-blocking antibody, as well as P2Y(1) and P2Y(12) receptor antagonists, alone or in combination, reduce in contrast to aspirin human plaque-induced platelet thrombus formation under arterial flow. Although these new anti-platelet agents inhibit platelet thrombus formation after plaque rupture, more efficient platelet blockers are required.


Assuntos
Aspirina/farmacologia , Aterosclerose/complicações , Plaquetas/efeitos dos fármacos , Inibidores da Agregação Plaquetária/farmacologia , Complexo Glicoproteico GPIb-IX de Plaquetas/antagonistas & inibidores , Antagonistas do Receptor Purinérgico P2 , Trombose/prevenção & controle , Difosfato de Adenosina/análogos & derivados , Difosfato de Adenosina/farmacologia , Monofosfato de Adenosina/análogos & derivados , Monofosfato de Adenosina/farmacologia , Anticorpos Monoclonais/farmacologia , Aspirina/uso terapêutico , Aterosclerose/sangue , Testes de Coagulação Sanguínea/métodos , Plaquetas/metabolismo , Estenose das Carótidas/complicações , Relação Dose-Resposta a Droga , Hemorreologia , Humanos , Agregação Plaquetária/efeitos dos fármacos , Inibidores da Agregação Plaquetária/uso terapêutico , Complexo Glicoproteico GPIb-IX de Plaquetas/imunologia , Complexo Glicoproteico GPIb-IX de Plaquetas/metabolismo , Receptores Purinérgicos P2/metabolismo , Receptores Purinérgicos P2Y1 , Receptores Purinérgicos P2Y12 , Trombose/sangue , Trombose/etiologia , Trombose/metabolismo , Fatores de Tempo , Fator de von Willebrand/metabolismo
14.
Thromb Haemost ; 96(6): 781-8, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17139373

RESUMO

Several methods are used to analyse platelet function in whole blood. A new device to measure whole blood platelet aggregation has been developed, called multiple electrode platelet aggregometry (MEA). Our aim was to evaluate MEA in comparison with the single platelet counting (SPC) method for the measurement of platelet aggregation and platelet inhibition by aspirin or apyrase in diluted whole blood. Platelet aggregation induced by different concentrations of ADP, collagen and TRAP-6 and platelet inhibition by apyrase or aspirin were determined in citrateor hirudin-anticoagulated blood by MEA and SPC. MEA indicated that spontaneous platelet aggregation was lower, and stimulated platelet aggregation was higher in hirudin- than citrate-anticoagulated blood. In hirudin-anticoagulated, but not citrate-anticoagulated blood, spontaneous platelet aggregation measured by MEA was inhibited by apyrase. For MEA compared with SPC the dose response-curves of agonist-induced platelet aggregation in citrate- and hirudin-blood showed similar EC50 values for TRAP, and higher EC50 values for ADP (non-significant) and collagen (p < 0.05). MEA and the SPC method gave similar results concerning platelet-inhibition by apyrase and aspirin. MEA was more sensitive than SPC to the inhibitory effect of aspirin in collagen-induced aggregation. In conclusion, MEA is an easy, reproducible and sensitive method for measuring spontaneous and stimulated platelet aggregation, and evaluating antiplatelet drugs in diluted whole blood. The use of hirudin as an anticoagulant is preferable to the use of citrate. MEA is a promising technique for experimental and clinical applications.


Assuntos
Eletrodos , Agregação Plaquetária , Testes de Função Plaquetária/instrumentação , Difosfato de Adenosina/farmacologia , Anticoagulantes/farmacologia , Apirase/farmacologia , Aspirina/farmacologia , Preservação de Sangue/métodos , Citratos/farmacologia , Colágeno/farmacologia , Relação Dose-Resposta a Droga , Impedância Elétrica , Hirudinas/farmacologia , Humanos , Técnicas In Vitro , Fragmentos de Peptídeos/farmacologia , Agregação Plaquetária/efeitos dos fármacos , Inibidores da Agregação Plaquetária/farmacologia , Contagem de Plaquetas , Valores de Referência , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Citrato de Sódio , Fatores de Tempo
15.
Life Sci ; 79(4): 317-23, 2006 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-16480745

RESUMO

It has been shown that PARP inhibition is protective in several models of ischemia-reperfusion injury including cardiac, cerebral and renal ones. Due to their ability to reduce myocardial necrosis and to improve myocardial function PARP inhibitors emerged as candidates for treating various cardiovascular diseases including acute myocardial ischemia. Since the pathophysiology of acute ischemic cardiac diseases involves haemostatic impairment and the therapeutic regimen includes antithrombotic drugs, we investigated the effect of the potent poly(ADP-ribose) polymerase (PARP) inhibitor INO-1001 alone and in combination with platelet aggregation inhibitors (aspirin, eptifibatide and tirofiban), unfractionated heparin, low molecular weight heparin (enoxaparin) or the recombinant fibrinolytic drug (alteplase), on various haemostatic parameters in vitro. ADP- and epinephrine-induced platelet aggregation was evaluated by optical aggregometry in the presence or absence of different concentrations of INO-1001, in combination with aspirin, tirofiban, eptifibatide or saline on ten healthy volunteers' platelet rich plasma (PRP). Activated partial thromboplastin time, Anti-Xa activity and euglobulin lysis time were determined in the presence or absence of different concentrations of INO-1001, in combination with sodium heparin, enoxaparin or alteplase, respectively. INO-1001, on its own does not affect the measured platelet, and haemostatic functions, i.e. does not reduce the respective anti-platelet, anti-coagulant and thrombolytic activity of therapeutically relevant concentrations of aspirin, tirofiban, eptifibatide, enoxaparin and alteplase in vitro. INO-1001 enhanced the effects of heparins above therapeutic ranges; the magnitude of this effect was negligible. Consequently, the PARP inhibitor INO-1001 can be safely applied together with the drugs tested.


Assuntos
Coagulação Sanguínea/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Indóis/farmacologia , Inibidores da Agregação Plaquetária/farmacologia , Inibidores de Poli(ADP-Ribose) Polimerases , Aspirina/farmacologia , Plaquetas/efeitos dos fármacos , Plaquetas/metabolismo , Relação Dose-Resposta a Droga , Combinação de Medicamentos , Eptifibatida , Inibidores do Fator Xa , Feminino , Heparina/farmacologia , Humanos , Masculino , Tempo de Tromboplastina Parcial , Peptídeos/farmacologia , Tirofibana , Ativador de Plasminogênio Tecidual/farmacologia , Tirosina/análogos & derivados , Tirosina/farmacologia
16.
Orv Hetil ; 146(41): 2121-5, 2005 Oct 09.
Artigo em Húngaro | MEDLINE | ID: mdl-16304806

RESUMO

INTRODUCTION: In rare cases of thromboembolic diseases developing in young age, venous and arterial thromboembolism can occur simultaneously. AIMS: To detect the venous and the arterial risk factors in a severe thrombophilic family. A 47-years-old female with severe atherosclerosis and recurrent deep vein thrombosis, and 6 members of her family were analysed. METHODS: The following haemostatic and molecular genetic investigations were performed: besides the rutin haemostatic parameters, risk factors for venous thrombembolic disease, risk factors for venous and arterial thrombosis (plasma homocysteine level, MTHFR C677T polymorphism) were determined. This panel was completed with the measurement of lipoprotein (a), von Willebrand factor, plasminogen activator inhibitor-1 antigen, serum total cholesterin, HDL cholesterin, C reactive protein and PIA2 variant. The propositus was proven to have type I antithrombin deficiency, elevated homocysteine level, homozygous MTHFR C677T polymorphism, elevated Lp(a), vWF:Ag, and PAI-1:Ag levels. RESULTS: All family members had a combination of cardiovascular risk factors (in 4 cases elevated homocysteine level, in 3 cases elevated Lp(a), in 2 cases elevated vWF:Ag, in 4 cases increased PAI-1 level). These risk factors were combined in three cases with type I antithrombin deficiency. Despite of the presence of atherosclerotic risk factors in the family, arterial thrombotic disease could be detected only in two patients with antithrombin deficiency. CONCLUSIONS: The results of the investigated family indicate that in case of combination of venous and arterial thromboembolic risk factors, antithrombin deficiency may contribute to the manifestation of arterial thromboembolic diseases.


Assuntos
Fibrina/deficiência , Trombofilia/metabolismo , Trombose/etiologia , Adulto , Proteína C-Reativa/metabolismo , Colesterol/sangue , Cisteína , Feminino , Predisposição Genética para Doença , Homocisteína/sangue , Humanos , Masculino , Linhagem , Inibidor 1 de Ativador de Plasminogênio/imunologia , Polimorfismo Genético , Fatores de Risco , Treonina , Trombofilia/genética , Trombose/sangue , Trombose/genética , Trombose/metabolismo , Trombose Venosa/etiologia , Fator de von Willebrand/metabolismo
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