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1.
Nat Commun ; 12(1): 4663, 2021 08 02.
Article in English | MEDLINE | ID: mdl-34341358

ABSTRACT

Vaccine-induced thrombotic thrombocytopenia with cerebral venous thrombosis is a syndrome recently described in young adults within two weeks from the first dose of the ChAdOx1 nCoV-19 vaccine. Here we report two cases of malignant middle cerebral artery (MCA) infarct and thrombocytopenia 9-10 days following ChAdOx1 nCoV-19 vaccination. The two cases arrived in our facility around the same time but from different geographical areas, potentially excluding epidemiological links; meanwhile, no abnormality was found in the respective vaccine batches. Patient 1 was a 57-year-old woman who underwent decompressive craniectomy despite two prior, successful mechanical thrombectomies. Patient 2 was a 55-year-old woman who developed a fatal bilateral malignant MCA infarct. Both patients manifested pulmonary and portal vein thrombosis and high level of antibodies to platelet factor 4-polyanion complexes. None of the patients had ever received heparin in the past before stroke onset. Our observations of rare arterial thrombosis may contribute to assessment of possible adverse effects associated with COVID-19 vaccination.


Subject(s)
COVID-19 Vaccines/adverse effects , COVID-19/immunology , Cerebral Infarction/chemically induced , Purpura, Thrombocytopenic, Idiopathic/chemically induced , SARS-CoV-2/immunology , Thrombosis/chemically induced , Autoantibodies/blood , Autoantibodies/immunology , COVID-19/virology , COVID-19 Vaccines/administration & dosage , COVID-19 Vaccines/immunology , Cerebral Infarction/diagnostic imaging , ChAdOx1 nCoV-19 , Computed Tomography Angiography/methods , Female , Humans , Magnetic Resonance Imaging/methods , Middle Aged , Platelet Factor 4/immunology , Purpura, Thrombocytopenic, Idiopathic/diagnostic imaging , SARS-CoV-2/physiology , Thrombosis/diagnostic imaging , Tomography, X-Ray Computed/methods , Vaccination/adverse effects , Venous Thrombosis/chemically induced , Venous Thrombosis/diagnostic imaging
2.
Transplant Proc ; 51(9): 2986-2990, 2019 Nov.
Article in English | MEDLINE | ID: mdl-31711580

ABSTRACT

Left ventricular assist device (LVAD) management is very challenging since many adverse events can occur in ongoing patients. Inadequate anticoagulation treatment can lead to life-threatening situations like ischemic stroke or pump thrombosis. The main intention of our study was to investigate if early identification of aspirin nonresponders by using aggregometry can improve anticoagulation management, reducing the risk of pump thrombosis. METHODS: From December 2010 to May 2018, 24 patients were implanted with a HeartMate II (HMII), 6 received a HeartWare HVAD system--full support VAD (HVAD), and 22 received a HeartMate III (HMIII). All patients were maintained with a target INR of 2.0 to 3.0. When the aggregometry test revealed a normal platelet function, 100 mg of aspirin were initiated. Only aspirin nonresponders were early identified by repeating the aggregometry after 7 days of aspirin administration. In acetylsalicylic acid nonresponder patients, 75 mg of clopidogrel was used, and the patients were tested again. Ticlopidine (250 mg) was used when clopidogrel was unsuccessful. RESULTS: Four patients required modification in antiplatelet therapy. Three patients (5%), 2 HVAD and 1 HMII, suffered from pump thrombosis. One patient died as a consequence of a large intracranial hemorrhagic event following thrombolytic treatment. One patient required a pump exchange; in 1 patient, thrombolytic infusion was conducted successfully. CONCLUSION: Reported rates of pump thrombosis at 12 months for patients implanted with commonly used LVADs were 6% to 12% for axial-flow pumps and 8% with centrifugal-flow devices. In our series, the reported 5% overall incidence of pump thrombosis encourages the routine use of an aggregometry test for early identification of aspirin nonresponders.


Subject(s)
Aspirin/therapeutic use , Blood Coagulation Tests/methods , Heart-Assist Devices/adverse effects , Platelet Aggregation Inhibitors/therapeutic use , Thrombosis/etiology , Thrombosis/prevention & control , Blood Coagulation/drug effects , Drug Resistance , Female , Humans , Incidence , Male , Middle Aged , Risk Assessment , Thrombosis/epidemiology
3.
Eur Rev Med Pharmacol Sci ; 22(23): 8487-8496, 2018 12.
Article in English | MEDLINE | ID: mdl-30556891

ABSTRACT

OBJECTIVE: Endometriosis is a debilitating disease characterized by chronic inflammation. The transporter multidrug resistance-associated protein 4 (MRP4/ABCC4) is expressed in human endometrial tissue; it is overexpressed in ectopic endometrial tissue, and is modulated by the anti-inflammatory lipid Lipoxin A4 (LXA4). Recently, it was demonstrated that aspirin induces platelet MRP4 over-expression, through genomic modulation in megakaryocytes. Since patients with endometriosis frequently use aspirin or other non-aspirin Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), the aim of this study was to verify whether aspirin and other NSAIDs enhance MRP4 expression in 12Z human endometriotic epithelial cells and whether this was peroxisome proliferator-activated receptor alpha (PPARa) dependent. MATERIALS AND METHODS: MRP4 and PPARa expression was analyzed by Q-RT-PCR using TaqMan® Master Mix and TaqMan® Assay Reagents (Life Technologies, Monza, Italy) and Western blot. RESULTS: In 12Z cells, aspirin and other NSAIDs enhanced MRP4 mRNA and protein expression; these treatments also induced PPARa expression. Aspirin and diclofenac-induced increases in MRP4 expression were not observed in cells where PPARa was knocked down using siRNA. NSAIDs-induced MRP4 expression was correlated with augmented PGE2 secretion, indicating functional relevance. CONCLUSIONS: MRP4 expression was increased in cells treated with NSAIDs and the nuclear receptor PPARa is involved. Elevated PGE2 levels in cell supernatants correlate with its increased transport by MRP4 after NSAID treatment. More importantly, we provide evidence that in endometriotic epithelial cells aspirin and non-aspirin NSAIDs treatments alter gene expression.


Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Endometriosis/drug therapy , Multidrug Resistance-Associated Proteins/genetics , PPAR alpha/metabolism , Aspirin/pharmacology , Cell Line , Diclofenac/pharmacology , Endometriosis/metabolism , Endometrium/metabolism , Epithelial Cells/metabolism , Female , Humans , Italy , Lipoxins/metabolism , RNA, Messenger/metabolism , RNA, Small Interfering/metabolism
4.
Platelets ; 28(7): 728-730, 2017 Nov.
Article in English | MEDLINE | ID: mdl-28287032

ABSTRACT

Heparin-induced thrombocytopenia (HIT) is a thrombotic complication of heparin therapy. The most used functional method for HIT diagnosis is serotonin release assay (SRA). A different functional method based on ATP release with luciferin/luciferase long-life and stable luminescent signal is used here, which is shown to be comparable for accuracy with SRA in both negative (patients 4Ts ≤3, and negative for both anti-PF4/heparin immunoassay and SRA) and positive (4Ts >3, and positive for both PF4/heparin antibodies and SRA) patients. Our results show that ATP release is higher in washed platelets activated by sera from positive patients than in platelets activated by sera from negative patients. In conclusion, we demonstrate that ATP release assay is a valid alternative method to SRA for the identification of pathogenic anti-PF4/heparin antibodies.


Subject(s)
Adenosine Triphosphate/blood , Antibodies/blood , Anticoagulants/adverse effects , Heparin/adverse effects , Luminescent Measurements/methods , Serotonin/blood , Thrombocytopenia/diagnosis , Adult , Aged , Anticoagulants/immunology , Blood Platelets/immunology , Blood Platelets/pathology , Female , Firefly Luciferin/chemistry , Follow-Up Studies , Gene Expression , Heparin/immunology , Humans , Immunoassay/methods , Luciferases, Firefly/chemistry , Male , Middle Aged , Platelet Factor 4/genetics , Platelet Factor 4/immunology , Thrombocytopenia/blood , Thrombocytopenia/chemically induced , Thrombocytopenia/immunology
5.
Clin Exp Obstet Gynecol ; 43(3): 354-7, 2016.
Article in English | MEDLINE | ID: mdl-27328490

ABSTRACT

PURPOSE OF INVESTIGATION: The aim of this study was to evaluate the correlation between endometriosis and pathologies on an immune basis for the possible involvement of the immune system in the pathogenesis of endometriosis. MATERIALS AND METHODS: In this retrospective study, data of 304 patients with endometriosis and 318 without endometriosis were collected in a uniform manner for both groups and inserted into two databases, respectively, for patients with and without endometriosis. The authors calculated the percentages of patients with allergies, autoimmune diseases, asthma in both groups, and later statistical analysis were performed with two different chi-square tests. RESULTS: The results obtained have shown that patients with endometriosis have a higher prevalence of allergies (p = 0.0003) and coexistence of both allergies and autoimmune diseases (p = 0.0274), compared to those without. CONCLUSIONS: The present study seems to support the possible association between endometriosis and allergic diseases.


Subject(s)
Asthma/epidemiology , Autoimmune Diseases/epidemiology , Endometriosis/epidemiology , Hypersensitivity/epidemiology , Adult , Antigen-Presenting Cells/immunology , Asthma/immunology , Autoimmune Diseases/immunology , Case-Control Studies , Chi-Square Distribution , Comorbidity , Endometriosis/immunology , Female , Humans , Hypersensitivity/immunology , Immunity, Cellular/immunology , Immunity, Humoral/immunology , Interleukin-10/immunology , Interleukin-12/immunology , Italy/epidemiology , Middle Aged , Prevalence , Retrospective Studies , Th1 Cells/immunology , Th2 Cells/immunology , Tumor Necrosis Factor-alpha/immunology , Young Adult
6.
Eur J Gynaecol Oncol ; 37(1): 122-5, 2016.
Article in English | MEDLINE | ID: mdl-27048123

ABSTRACT

INTRODUCTION: Uterine sarcomas are rare and aggressive tumors. In some cases they can cause rupture of the uterus with or without clinical and radiological symptoms. Therefore, it is important to observe patients with clinical and/or radiological suspicion of sarcoma, even when there are no clinical manifestations. CASE REPORT: A 71-year old woman, who was under the authors' observation for pain in the right iliac fossa. The US and the CT scan showed an abdominal-pelvic mass.Laboratory tests showed a slight but progressive reduction of haemoglobin, which could not be explained by the clinical symptoms and by the results of the imaging tests. During the surgical intervention, a small amount of peritoneal fluid, an increased uterine volume, and a subverted anatomy were observed A haematoma was found in the uterus and this could explain the progressive reduction of haemoglobin and the very low presence of peritoneal effusion. CONCLUSION: The rupture of the uterus could not have been suspected as the patient did not have any type of symptoms, except for the slow and progressive reduction in the haemoglobin value. Therefore, it is important to observe patients with clinical and/or radiological suspicion of sarcoma, even when there are no clinical manifestations.


Subject(s)
Hematoma/etiology , Hemoglobins/analysis , Leiomyosarcoma/complications , Uterine Neoplasms/complications , Aged , Female , Humans , Leiomyosarcoma/pathology , Uterine Neoplasms/pathology
7.
World J Surg Oncol ; 14: 105, 2016 Apr 07.
Article in English | MEDLINE | ID: mdl-27056684

ABSTRACT

BACKGROUND: The purpose of this study is to compare laparoscopy (LPS) and laparotomy (LPT), in terms of surgical outcomes, in elderly patients (>65 years) with adnexal masses. METHODS: We retrospectively reviewed a series of women older than 65 who had a diagnosis of adnexal masses. Then, all patients were divided into two different groups according to the type of surgery: 27 who underwent LPS (LPS group) and 24 who underwent LPT (LPT group). We took into consideration: age, comorbidity, histological diagnosis, surgery approach, and surgical outcome. Then, we calculated the percentages of all of these data and then χ (2) test and t-Student test were used to calculate the p value, to compare the two surgical techniques. A p value lower than 0.05 was considered to be statistically significant. RESULTS: At first, we evaluated the relation between the diagnosis and the surgery approach, and we obtained statistically significant results for serous cyst, adenocarcinoma serous/mucinous, and others, and the table highlights that some of the benign masses were mostly treated with LPS, while borderline and malignant masses were treated with LPT. Then, we evaluated the comorbidities of the patients, and we found that those cases had a significantly higher prevalence of cardiovascular disease and metabolic diseases. Finally, we compared the surgery outcome of LPS versus LPT surgeries for adnexal masses in elderly women, and there were statistically significant results for postoperative complications, number of patients who needed drainage, and number of days of hospitalization after surgery. CONCLUSIONS: Our results demonstrated that the patients who underwent LPS, compared to the patients who underwent LPT, have better outcomes in terms of postoperative complications (7.4 % with LPS and 37 % with LPT), number of patients who needed drainage (11.1 % with LPS and 62.5 % with LPT), and number of days of hospitalization after surgery, in term of mean (5 for LPS and 10.9 in term of LPT).


Subject(s)
Adnexal Diseases/surgery , Laparoscopy/methods , Laparotomy/methods , Ovarian Neoplasms/surgery , Postoperative Complications , Adnexal Diseases/pathology , Aged , Aged, 80 and over , Female , Follow-Up Studies , Humans , Neoplasm Staging , Ovarian Neoplasms/pathology , Prognosis , Retrospective Studies
8.
Biomed Res Int ; 2015: 512027, 2015.
Article in English | MEDLINE | ID: mdl-26106610

ABSTRACT

High mobility group box 1 (HMGB1) is an ubiquitous protein that plays different roles in the nucleus, cytoplasm, and extracellular space. It is an important DAMP molecule that allows communication between damaged or tumor cells and the immune system. Tumor cells exploit HMGB1's ability to activate intracellular pathways that lead to cell growth and migration. Papillary thyroid cancer is a well-differentiated tumor and is often used to study relationships between cells and the inflammatory microenvironment as the latter is characterized by high levels of inflammatory cells and cytokines. Anaplastic thyroid cancer is one of the most lethal human cancers in which many microRNAs and tumor suppressor genes are deregulated. Upregulation of microRNAs 221 and 222 has been shown to induce the malignant phenotype in many human cancers via inhibition of PTEN expression. In this study we suggest that extracellular HMGB1 interaction with RAGE enhances expression of oncogenic cluster miR221/222 that in turn inhibits tumor suppressor gene PTEN in two cell lines derived from human thyroid anaplastic and papillary cancers. The newly identified pathway HMGB1/RAGE/miR221/222 may represent an effective way of tumor escape from immune surveillance that could be used to develop new therapeutic strategies against anaplastic tumors.


Subject(s)
HMGB1 Protein/genetics , MicroRNAs/genetics , PTEN Phosphohydrolase/genetics , Thyroid Neoplasms/genetics , Apoptosis/genetics , Cell Proliferation/genetics , HMGB1 Protein/metabolism , Humans , MicroRNAs/metabolism , PTEN Phosphohydrolase/metabolism , Signal Transduction , Thyroid Neoplasms/pathology
9.
Gynecol Endocrinol ; 31(4): 253-7, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25482873

ABSTRACT

INTRODUCTION: Assisted reproduction techniques are the frequent treatment of infertility. Despite the advances in science and technology, the management of poor responder patients is still considered as one of the most urgent problems. The lack of unified definition makes the management of the poor responder patients very difficult. The aim of this review is to examine and compare the different studies done about the problem of poor responder patients. METHODS: On an online research of MEDLINE/PUBMED, we found several studies on pharmacological treatment for poor responders' patients. RESULTS: Our review shows that in the years numerous therapies for the management of these patients who do not respond to ovarian stimulation have been evaluated and studied, but the main problem is the large and still not well-defined meaning of poor responder women. CONCLUSION: The management of the poor responder patients is very difficult. Currently, there is no any standard treatment for poor responder patients. Considering the importance of the problem, it is important to identify a diagnostic and therapeutic target. Our review shows that there are many studies with different therapeutic approaches which deserve further in-depth study to standardize diagnostic and therapeutic target.


Subject(s)
Drug Resistance , Fertility Agents, Female/pharmacology , Fertilization in Vitro , Infertility, Female/therapy , Ovulation Induction/methods , Ovulation/drug effects , Precision Medicine , Drug Resistance, Multiple , Drug Therapy, Combination , Female , Fertility Agents, Female/administration & dosage , Fertilization in Vitro/trends , Humans , Infertility, Female/diagnosis , Ovarian Reserve , Ovulation Induction/trends , Pregnancy , Pregnancy Rate , Terminology as Topic
10.
J Thromb Haemost ; 12(4): 550-9, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24460629

ABSTRACT

BACKGROUND: The activation of platelet CLEC-2 by podoplanin on lymphatic endothelial cells (LECs) has a critical role in prevention of mixing of lymphatic and blood vasculatures during embryonic development. Paradoxically, LECs release cAMP and cGMP-elevating agents, prostacyclin (PGI2 ) and nitric oxide (NO), respectively, which are powerful inhibitors of platelet activation. This raises the question of how podoplanin is able to activate CLEC-2 in the presence of the inhibitory cyclic nucleotides. OBJECTIVES: We investigated the influence of cyclic nucleotides on CLEC-2 signaling in platelets. METHODS: We used rhodocytin, CLEC-2 monoclonal antibody, LECs and recombinant podoplanin as CLEC-2 agonists on mouse platelets. The effects of the cyclic nucleotide-elevating agents PGI2 , forskolin and the NO-donor GSNO were assessed with light transmission aggregometry, flow cytometry, protein phosphorylation and fluorescent imaging of platelets on LECs. RESULTS: We show that platelet aggregation induced by CLEC-2 agonists is resistant to GSNO but inhibited by PGI2 . The effect of PGI2 is mediated through decreased phosphorylation of CLEC-2, Syk and PLCγ2. In contrast, adhesion and spreading of platelets on recombinant podoplanin, CLEC-2 antibody and LECs is not affected by PGI2 and GSNO. Consistent with this, CLEC-2 activation of Rac, which is required for platelet spreading, is not altered in the presence of PGI2 . CONCLUSIONS: The present results demonstrate that platelet adhesion and activation on CLEC-2 ligands or LECs is maintained in the presence of PGI2 and NO.


Subject(s)
Blood Platelets/cytology , Cyclic AMP/metabolism , Cyclic GMP/metabolism , Lectins, C-Type/metabolism , Membrane Glycoproteins/metabolism , Platelet Activation , Animals , Blood Platelets/drug effects , Calcium/metabolism , Cell Adhesion , Epoprostenol/metabolism , Mice , Mice, Inbred C57BL , Nitric Oxide/metabolism , Platelet Adhesiveness , Platelet Aggregation , Viper Venoms/metabolism
11.
Cell Death Dis ; 3: e429, 2012 Nov 22.
Article in English | MEDLINE | ID: mdl-23171849

ABSTRACT

Adaptation to endoplasmic reticulum (ER) stress relies on activation of the unfolded protein response (UPR) and induction of autophagy. Indeed, cells die if ER stress is not countered by the UPR. Here we show in U937 cells that the ER stressors tunicamycin and thapsigargin cause increased expression of c-Jun N-terminal kinase 2 (JNK2), which allows regulation of the UPR, whose silencing or pharmacological inhibition delays BiP (immunoglobulin heavy-chain binding protein) upregulation, and causes earlier and greater expression of CCAAT/enhancer-binding protein-homologous protein (CHOP). Furthermore, we show that pharmacological inhibition or silencing of JNK2 causes accumulation of both p62 and the acidic compartment, caspase 3 activation and apoptosis. Our results reveal that JNK2 prevents accumulation of the acidic compartment in U937 cells undergoing autophagic flux and, by this mechanism, it keeps stressed cells alive. Our findings highlight a potential role for JNK2 in tumor cell survival, senescence and neurodegenerative diseases, in which ER stress, autophagy and lysosome activity are known to interplay.


Subject(s)
Endoplasmic Reticulum Stress , Mitogen-Activated Protein Kinase 9/metabolism , Neoplasms/enzymology , Neoplasms/physiopathology , Apoptosis , Caspase 3/genetics , Caspase 3/metabolism , Cell Survival , Humans , Mitogen-Activated Protein Kinase 9/genetics , Neoplasms/genetics , Neoplasms/metabolism , Proto-Oncogene Proteins c-myc/genetics , Proto-Oncogene Proteins c-myc/metabolism , Transcription Factor CHOP/genetics , Transcription Factor CHOP/metabolism , U937 Cells
12.
Haemophilia ; 16(5): 805-12, 2010 Sep 01.
Article in English | MEDLINE | ID: mdl-20345392

ABSTRACT

SUMMARY: Platelet transfusions, main therapy of Glanzmann Thromboasthenia (GT), can induce an allo-immunization against human leucocyte antigen and integrin alphaIIbbeta3. We have investigated in our GT patients the rate of allo-immunization and of refractoriness to platelet transfusions. From 1975 until December 2005, we have followed 17 GT patients: 14 type 1, 3 variant type; nine females, eight males; median age at diagnosis 9.8 years (range 1-44.5); median age at the time of the study 35.5 years (range 23.6-68.5). In our patients, 121 bleeding episodes occurred (24 severe, 37 moderate, and 60 mild). Ten major and 22 minor surgical procedures have been performed. Two spontaneous deliveries and three caesarian sections with five live births were performed; moreover, one late foetal loss occurred, and one voluntary abortion was performed. Sixteen of 17 patients have been transfused at least once in life with platelets and/or red blood cells (RBC). All transfused patients have been investigated for the presence of anti-HLA and anti-integrin alphaIIbbeta3 allo-antibodies. The positiveness of allo-antibodies has been demonstrated in 4/16 transfused patients (25%): isolated for anti-HLA in two; isolated for anti-integrin alphaIIbbeta3 in one; and combined in one. In spite of the presence of allo-antibodies, platelet transfusions have always been effective and the haemostasis was not compromised.


Subject(s)
HLA Antigens/immunology , Isoantibodies/analysis , Platelet Glycoprotein GPIIb-IIIa Complex/immunology , Platelet Transfusion , Thrombasthenia/immunology , Thrombasthenia/therapy , Adult , Aged , Delivery, Obstetric , Enzyme-Linked Immunosorbent Assay , Female , Genotype , Humans , Integrin alpha2/genetics , Integrin beta3/genetics , Male , Middle Aged , Mutation/genetics , Phenotype , Pregnancy , Thrombasthenia/genetics , Young Adult
13.
Curr Cancer Drug Targets ; 8(5): 414-20, 2008 Aug.
Article in English | MEDLINE | ID: mdl-18690847

ABSTRACT

Recent phase II randomised trials in colorectal cancer failed to demonstrate any advantage of celecoxib combined with standard chemotherapy; some authors even reported that the addition of celecoxib to irinotecan and oxaliplatin in colon cancer results in an inferior response rate. This observation leads to the hypothesis that there are pharmacokinetic interactions between celecoxib and chemotherapeutic drugs. The aim of the study was to investigate the induction by celecoxib of some multidrug resistance proteins, MRP1, MRP2, MRP4 and MRP5, involved in the transport of irinotecan and 5-FU. WiDr and COLO-205 cells were treated with celecoxib at a clinically relevant concentration. A viability assay was performed by treating cells with chemotherapy alone and chemotherapy plus celecoxib. The expression of MRP1, MRP2, MRP4 and MRP5 was analysed by RT-PCR and Western blot analysis. The sub cellular localization of MRP4 and MRP5 was investigated by cryoimmunoelectron microscopy. In both cell lines celecoxib induced MRP4 and MRP5 over-expression at RNA and protein levels. No induction of MRP1 and MRP2 was observed in treated cells compared to controls. Cryoimmunoelectron microscopy showed increased MRP4 and MRP5 immunolabeling in celecoxib treated cells both at cytoplasmic level and along the plasma membrane. Our findings suggest that the low response rate observed in clinical trials using celecoxib added to 5-fluorouracil and irinotecan may reflect celecoxib-mediated extrusion of chemotherapeutic drugs from cancer cells through the up regulation of ATP-binding cassette proteins. Our findings, together with the results of clinical trials, may suggest that the combined use of celecoxib and drugs that are substrate for MRP4/MRP5 should be avoided.


Subject(s)
ATP Binding Cassette Transporter, Subfamily B/metabolism , Colonic Neoplasms/drug therapy , Colonic Neoplasms/metabolism , Cyclooxygenase Inhibitors/therapeutic use , Pyrazoles/therapeutic use , Sulfonamides/therapeutic use , Blotting, Western , Celecoxib , Cell Membrane/metabolism , Cell Survival/drug effects , Colonic Neoplasms/pathology , Cytoplasm/metabolism , Drug Resistance, Neoplasm , Humans , Immunoenzyme Techniques , Multidrug Resistance-Associated Protein 2 , Multidrug Resistance-Associated Proteins/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Subcellular Fractions , Tumor Cells, Cultured , Up-Regulation
16.
J Thromb Haemost ; 3(12): 2784-9, 2005 Dec.
Article in English | MEDLINE | ID: mdl-16359516

ABSTRACT

BACKGROUND: Patients treated with aspirin may have a reduced sensitivity to its antiplatelet effect. The mechanism accounting for such a reduced sensitivity might involve an impaired interaction of aspirin with cyclooxygenase-1 (COX)-1. OBJECTIVE: We sought to investigate whether platelets from patients under chronic treatment with aspirin still produce TxA2 and whether there is any relationship between the eventual persistent TxA2 formation and platelet aggregation. Finally, whether platelet-derived TxA2 can be inhibited by in vitro addition of aspirin. METHODS: Collagen-induced platelet aggregation and thromboxane-A2 (TxA2) were measured in 196 patients treated with aspirin (100-330 mg day(-1)) because of previous vascular events or presence of risk factors of atherosclerosis. RESULTS: Collagen-induced TxA2 production of the entire cohort was 128.7 +/- 21.6 pg 10(-8) cells, and was significantly correlated with platelet aggregation (Spearman's correlation coefficient = 0.44; P < 0.0001). Patients in the highest quartile of TxA2 showed higher platelet response to collagen (P < 0.0001) when compared with those in the lowest quartile. In a subgroup of 96 patients, platelets were treated in vitro with a TxA2 receptor antagonist (13-azaprostanoic acid) or aspirin before stimulation with collagen. 13-APA acid significantly inhibited platelet aggregation. Aspirin reduced (-72.9%) TxA2 production in patients with TxA2 values above the median but it was ineffective in those with TxA2 values below the median. CONCLUSION: In some patients chronically treated with aspirin platelet production of TxA2 may persist and account for enhanced platelet aggregation. Incomplete inhibition of COX-1 seems to be implicated in persistent TxA2 production.


Subject(s)
Aspirin/pharmacology , Blood Platelets/metabolism , Drug Resistance , Thromboxane A2/biosynthesis , Aged , Aspirin/administration & dosage , Cardiovascular Diseases/blood , Cardiovascular Diseases/drug therapy , Collagen , Cyclooxygenase 1/drug effects , Dose-Response Relationship, Drug , Female , Humans , Male , Middle Aged , Platelet Aggregation/drug effects , Thromboxane A2/antagonists & inhibitors , Thromboxane A2/physiology
19.
Am J Physiol Heart Circ Physiol ; 284(1): H41-8, 2003 Jan.
Article in English | MEDLINE | ID: mdl-12388290

ABSTRACT

Carnitine is a physiological cellular constituent that favors intracellular fatty acid transport, whose role on platelet function and O(2) free radicals has not been fully investigated. The aim of this study was to seek whether carnitine interferes with arachidonic acid metabolism and platelet function. Carnitine (10-50 microM) was able to dose dependently inhibit arachidonic acid incorporation into platelet phospholipids and agonist-induced arachidonic acid release. Incubation of platelets with carnitine dose dependently inhibited collagen-induced platelet aggregation, thromboxane A(2) formation, and Ca(2+) mobilization, without affecting phospholipase A(2) activation. Furthermore, carnitine inhibited platelet superoxide anion (O(2)(-)) formation elicited by arachidonic acid and collagen. To explore the underlying mechanism, arachidonic acid-stimulated platelets were incubated with NADPH. This study showed an enhanced platelet O(2)(-) formation, suggesting a role for NADPH oxidase in arachidonic acid-mediated platelet O(2)(-) production. Incubation of platelets with carnitine significantly reduced arachidonic acid-mediated NADPH oxidase activation. Moreover, the activation of protein kinase C was inhibited by 50 microM carnitine. This study shows that carnitine inhibits arachidonic acid accumulation into platelet phospholipids and in turn platelet function and arachidonic acid release elicited by platelet agonists.


Subject(s)
Arachidonic Acid/metabolism , Blood Platelets/physiology , Carnitine/pharmacology , Oxidative Stress/physiology , Blood Platelets/metabolism , Blood Proteins/metabolism , Calcium/metabolism , Humans , Intracellular Membranes/metabolism , Osmolar Concentration , Phospholipids/metabolism , Phosphorylation , Platelet Aggregation/physiology , Reactive Oxygen Species/metabolism , Thromboxane A2/biosynthesis
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