1
|
Cunha LC, Barreto LP, Valadares VS, Oliveira CFB, Vuitika L, Vilela MP, Cino EA, Silva AHDM, Nagem RAP, Chávez-Olórtegui C, Dias-Lopes C, Molina F, Felicori L. The C-terminal mutation beyond the catalytic site of brown spider phospholipase D significantly impacts its biological activities. Biochimie 2023; 211:122-130. [PMID: 36963559 DOI: 10.1016/j.biochi.2023.03.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 02/16/2023] [Accepted: 03/17/2023] [Indexed: 03/26/2023]
Abstract
Loxosceles spider envenomation results in dermonecrosis, principally due to phospholipases D (PLDs) present in the venom. These enzymes have a strongly conserved sequence, 273ATXXDNPW280, in the C-terminal region (SMD-tail) that make contact with β-sheets of the TIM barrel, in which the amino acids Asp277 and Trp280 establish the energetically strongest contacts. The SMD-tail is conserved in PLDs from different species but absent in the non-toxic PLD ancestral glycerophosphodiester phosphodiesterases (GDPDs). This work aims to understand the role of the C-terminal region in the structural stability and/or function of phospholipases D. Through site-directed mutagenesis of the rLiD1 protein (recombinant Loxosceles intermedia dermonecrotic protein 1), we produced two mutants: rLiD1D277A and rLiD1W280A (both with sphingomyelinase activity), in which Asp277 and Trp280 were replaced by alanine. rLiD1D277A showed similar sphingomyelinase activity but at least 2 times more dermonecrotic activity than rLiD1 (wild-type protein). Conversely, while the rLiD1W280A displayed a slight increase in sphingomyelinase activity, its biological activity was similar or lower compared to rLiD1, potentially due to its decreased thermostability and formation of amyloid aggregates. In conclusion, these new findings provide evidence that SMD-tail mutants impact the structure and function of these proteins and point out that residues outside the active site can even increase the function of these enzymes.
Collapse
Affiliation(s)
- Laís Cardoso Cunha
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas - ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Lucas Passos Barreto
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas - ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Veronica Silva Valadares
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas - ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Camila Franco Batista Oliveira
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas - ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Larissa Vuitika
- Department of Immunology, Institute of Biomedical Sciences IV, University of São Paulo (ICB-IV/USP), São Paulo, Brazil
| | - Maura Páscoa Vilela
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas - ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Elio A Cino
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas - ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | | | - Ronaldo A P Nagem
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas - ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Carlos Chávez-Olórtegui
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas - ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Camila Dias-Lopes
- Colégio Técnico, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Franck Molina
- CNRS, SYS2DIAG-ALCEDIAG, Cap Delta, 1682 Rue de La Valsière, 34184, Montpellier, France
| | - Liza Felicori
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas - ICB, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
| |
Collapse
|
2
|
Luo L, Xue Q, Qi Y, Zeng L, Liang S. Therapeutic effects of different polar fractions of hawthorn extract on blood stasis model rats revealed by liquid chromatography-mass spectrometry metabolomics. J Sep Sci 2021; 44:4005-4016. [PMID: 34490993 DOI: 10.1002/jssc.202100569] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 08/25/2021] [Accepted: 09/01/2021] [Indexed: 12/12/2022]
Abstract
Hawthorn, a commonly used traditional Chinese medicine, has been suggested to have therapeutic effects on cardiovascular disease. However, effective fractions of hawthorn extract in the treatment of cardiovascular disease, together with possible therapeutic mechanisms, remain unclear. This study aimed to investigate the effects of four different polar fractions of hawthorn extract on blood stasis model rats, and explore the possible metabolic mechanisms by using a liquid chromatography-mass spectrometry metabolomics approach. Evaluation of hemorheology and fibrinogen showed that n-butanol and ethyl acetate fractions of hawthorn extract had significant therapeutic effects on blood stasis model rats. Furthermore, metabolomics analysis showed that n-butanol and ethyl acetate fractions of hawthorn extract could reverse imbalanced biomarkers in plasma and urine of blood stasis model rats. Additionally, metabolic pathway analysis revealed that plasma biomarkers were responsible for several important pathways, including d-glutamine and d-glutamate metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, alanine, aspartate, and glutamate metabolism, sphingolipid metabolism, and arginine biosynthesis. Meanwhile, urine biomarkers were responsible for some important pathways, including phenylalanine metabolism, tyrosine metabolism, and lysine degradation. This study demonstrated that n-butanol and ethyl acetate fractions of hawthorn extract had significant therapeutic effects on blood stasis model rats, and the underlying mechanisms involved multiple metabolic pathways.
Collapse
Affiliation(s)
- Lan Luo
- College of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou, P. R. China.,Key Laboratory of Digital Quality Evaluation of Chinese Materia Medica of State Administrationof TCM, Guangdong Pharmaceutical University, Guangzhou, P. R. China.,Engineering & Technology Research Center for Chinese Materia Medica Quality of the Universities of Guangdong Province, Guangdong Pharmaceutical University, Guangzhou, P. R. China
| | - Qi Xue
- College of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou, P. R. China.,Key Laboratory of Digital Quality Evaluation of Chinese Materia Medica of State Administrationof TCM, Guangdong Pharmaceutical University, Guangzhou, P. R. China.,Engineering & Technology Research Center for Chinese Materia Medica Quality of the Universities of Guangdong Province, Guangdong Pharmaceutical University, Guangzhou, P. R. China
| | - Yue Qi
- College of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou, P. R. China.,Key Laboratory of Digital Quality Evaluation of Chinese Materia Medica of State Administrationof TCM, Guangdong Pharmaceutical University, Guangzhou, P. R. China.,Engineering & Technology Research Center for Chinese Materia Medica Quality of the Universities of Guangdong Province, Guangdong Pharmaceutical University, Guangzhou, P. R. China
| | - Lu Zeng
- College of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou, P. R. China.,Key Laboratory of Digital Quality Evaluation of Chinese Materia Medica of State Administrationof TCM, Guangdong Pharmaceutical University, Guangzhou, P. R. China.,Engineering & Technology Research Center for Chinese Materia Medica Quality of the Universities of Guangdong Province, Guangdong Pharmaceutical University, Guangzhou, P. R. China
| | - Shengwang Liang
- College of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou, P. R. China.,Key Laboratory of Digital Quality Evaluation of Chinese Materia Medica of State Administrationof TCM, Guangdong Pharmaceutical University, Guangzhou, P. R. China.,Engineering & Technology Research Center for Chinese Materia Medica Quality of the Universities of Guangdong Province, Guangdong Pharmaceutical University, Guangzhou, P. R. China
| |
Collapse
|
3
|
Staiculescu MC, Ramirez-Perez FI, Castorena-Gonzalez JA, Hong Z, Sun Z, Meininger GA, Martinez-Lemus LA. Lysophosphatidic acid induces integrin activation in vascular smooth muscle and alters arteriolar myogenic vasoconstriction. Front Physiol 2014; 5:413. [PMID: 25400583 PMCID: PMC4215695 DOI: 10.3389/fphys.2014.00413] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 10/06/2014] [Indexed: 01/16/2023] Open
Abstract
In vascular smooth muscle cells (VSMC) increased integrin adhesion to extracellular matrix (ECM) proteins, as well as the production of reactive oxygen species (ROS) are strongly stimulated by lysophosphatidic acid (LPA). We hypothesized that LPA-induced generation of ROS increases integrin adhesion to the ECM. Using atomic force microscopy (AFM) we determined the effects of LPA on integrin adhesion to fibronectin (FN) in VSMC isolated from rat (Sprague-Dawley) skeletal muscle arterioles. In VSMC, exposure to LPA (2 μM) doubled integrin-FN adhesion compared to control cells (P < 0.05). LPA-induced integrin-FN adhesion was reduced by pre-incubation with antibodies against β1 and β3 integrins (50 μg/ml) by 66% (P < 0.05). Inhibition of LPA signaling via blockade of the LPA G-protein coupled receptors LPAR1 and LPAR3 with 10 μM Ki16425 reduced the LPA-enhanced adhesion of VSCM to FN by 40% (P < 0.05). Suppression of ROS with tempol (250 μM) or apocynin (300 μM) also reduced the LPA-induced FN adhesion by 47% (P < 0.05) and 59% (P < 0.05), respectively. Using confocal microscopy, we observed that blockade of LPA signaling, with Ki16425, reduced ROS by 45% (P < 0.05), to levels similar to control VSMC unexposed to LPA. In intact isolated arterioles, LPA (2 μM) exposure augmented the myogenic constriction response to step increases in intraluminal pressure (between 40 and 100 mm Hg) by 71% (P < 0.05). The blockade of LPA signaling, with Ki16425, decreased the LPA-enhanced myogenic constriction by 58% (P < 0.05). Similarly, blockade of LPA-induced ROS release with tempol or gp91 ds-tat decreased the LPA-enhanced myogenic constriction by 56% (P < 0.05) and 55% (P < 0.05), respectively. These results indicate that, in VSMC, LPA-induced integrin activation involves the G-protein coupled receptors LPAR1 and LPAR3, and the production of ROS, and that LPA may play an important role in the control of myogenic behavior in resistance vessels through ROS modulation of integrin activity.
Collapse
Affiliation(s)
| | - Francisco I Ramirez-Perez
- Dalton Cardiovascular Research Center, University of Missouri Columbia, MO, USA ; Department of Bioengineering, University of Missouri Columbia, MO, USA
| | - Jorge A Castorena-Gonzalez
- Dalton Cardiovascular Research Center, University of Missouri Columbia, MO, USA ; Department of Bioengineering, University of Missouri Columbia, MO, USA
| | - Zhongkui Hong
- Dalton Cardiovascular Research Center, University of Missouri Columbia, MO, USA
| | - Zhe Sun
- Dalton Cardiovascular Research Center, University of Missouri Columbia, MO, USA
| | - Gerald A Meininger
- Dalton Cardiovascular Research Center, University of Missouri Columbia, MO, USA ; Department of Bioengineering, University of Missouri Columbia, MO, USA ; Department of Medical Pharmacology and Physiology, University of Missouri Columbia, MO, USA
| | - Luis A Martinez-Lemus
- Dalton Cardiovascular Research Center, University of Missouri Columbia, MO, USA ; Department of Bioengineering, University of Missouri Columbia, MO, USA ; Department of Medical Pharmacology and Physiology, University of Missouri Columbia, MO, USA
| |
Collapse
|
4
|
Lysophosphatidic acid (LPA) signaling in human and ruminant reproductive tract. Mediators Inflamm 2014; 2014:649702. [PMID: 24744506 PMCID: PMC3973013 DOI: 10.1155/2014/649702] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 01/24/2014] [Indexed: 01/28/2023] Open
Abstract
Lysophosphatidic acid (LPA) through activating its G protein-coupled receptors (LPAR 1–6) exerts diverse cellular effects that in turn influence several physiological processes including reproductive function of the female. Studies in various species of animals and also in humans have identified important roles for the receptor-mediated LPA signaling in multiple aspects of human and animal reproductive tract function. These aspects range from ovarian and uterine function, estrous cycle regulation, early embryo development, embryo implantation, decidualization to pregnancy maintenance and parturition. LPA signaling can also have pathological consequences, influencing aspects of endometriosis and reproductive tissue associated tumors. The review describes recent progress in LPA signaling research relevant to human and ruminant reproduction, pointing at the cow as a relevant model to study LPA influence on the human reproductive performance.
Collapse
|
5
|
Eriksson AC, Whiss PA. Nanomolar concentrations of adrenaline induce platelet adhesion in vitro. Platelets 2012; 24:129-35. [PMID: 22471400 DOI: 10.3109/09537104.2012.672780] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Adrenaline is a platelet activator having a resting plasma concentration of <1 nmol/l that increases to a few nmol/l during stress. However, most in vitro assays only detect effects of adrenaline in micromolar concentrations. This makes it difficult to estimate the relevance of in vitro data for the in vivo situation. The aim of this study was to investigate experimental conditions in vitro that could detect platelet effects of adrenaline in nanomolar concentrations. Platelet adhesion to albumin and collagen was evaluated with a static platelet adhesion assay. Our results show that 10 nmol/l adrenaline induced platelet adhesion to albumin in platelet-rich plasma (PRP) prepared at 140 × g, while 100 nmol/l was necessary in order to increase adhesion of platelets prepared at 220 × g. The mean platelet volume was increased after preparation at 140 × g, suggesting that large reactive platelets contributed to the increased adrenaline sensitivity. At optimal Mg(2+)-concentration, adhesion to collagen was increased by 10 nmol/l adrenaline irrespective of centrifugal force applied during PRP preparation. More specifically, we defined two populations where adhesion to collagen was increased by 10 nmol/l adrenaline either upon centrifugation at 140 × g but not 220 × g or vice versa. In some experiments, platelet adhesion to collagen was induced by 3 nmol/l adrenaline, which corresponds to concentrations achieved during stress in vivo. In summary, the static adhesion assay is able to detect platelet activating effects of adrenaline very close to physiological concentrations. This is rare for in vitro assays and motivates further research about adrenergic signalling in platelets.
Collapse
Affiliation(s)
- Andreas C Eriksson
- Division of Drug Research/Pharmacology, Department of Medical and Health Sciences, Linköping University , SE-581 85 Linköping , Sweden.
| | | |
Collapse
|
6
|
Horstman LL, Jy W, Ahn YS, Zivadinov R, Maghzi AH, Etemadifar M, Steven Alexander J, Minagar A. Role of platelets in neuroinflammation: a wide-angle perspective. J Neuroinflammation 2010; 7:10. [PMID: 20128908 PMCID: PMC2829540 DOI: 10.1186/1742-2094-7-10] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Accepted: 02/03/2010] [Indexed: 01/03/2023] Open
Abstract
OBJECTIVES This review summarizes recent developments in platelet biology relevant to neuroinflammatory disorders. Multiple sclerosis (MS) is taken as the "Poster Child" of these disorders but the implications are wide. The role of platelets in inflammation is well appreciated in the cardiovascular and cancer research communities but appears to be relatively neglected in neurological research. ORGANIZATION After a brief introduction to platelets, topics covered include the matrix metalloproteinases, platelet chemokines, cytokines and growth factors, the recent finding of platelet PPAR receptors and Toll-like receptors, complement, bioactive lipids, and other agents/functions likely to be relevant in neuroinflammatory diseases. Each section cites literature linking the topic to areas of active research in MS or other disorders, including especially Alzheimer's disease. CONCLUSION The final section summarizes evidence of platelet involvement in MS. The general conclusion is that platelets may be key players in MS and related disorders, and warrant more attention in neurological research.
Collapse
Affiliation(s)
- Lawrence L Horstman
- Wallace Coulter Platelet Laboratory, Division of Hematology and Oncology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Wenche Jy
- Wallace Coulter Platelet Laboratory, Division of Hematology and Oncology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Yeon S Ahn
- Wallace Coulter Platelet Laboratory, Division of Hematology and Oncology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Robert Zivadinov
- Buffalo Neuroimaging Analysis Center, The Jacobs Neurological Institute, Department of Neurology, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo NY, USA
| | - Amir H Maghzi
- Department of Neurology, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Masoud Etemadifar
- Department of Neurology, Isfahan University of Medical Sciences, Isfahan, Iran
| | - J Steven Alexander
- Department of Cellular and Molecular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
| | - Alireza Minagar
- Department of Neurology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
| |
Collapse
|
7
|
Static platelet adhesion, flow cytometry and serum TXB2 levels for monitoring platelet inhibiting treatment with ASA and clopidogrel in coronary artery disease: a randomised cross-over study. J Transl Med 2009; 7:42. [PMID: 19508722 PMCID: PMC2699331 DOI: 10.1186/1479-5876-7-42] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Accepted: 06/09/2009] [Indexed: 11/24/2022] Open
Abstract
Background Despite the use of anti-platelet agents such as acetylsalicylic acid (ASA) and clopidogrel in coronary heart disease, some patients continue to suffer from atherothrombosis. This has stimulated development of platelet function assays to monitor treatment effects. However, it is still not recommended to change treatment based on results from platelet function assays. This study aimed to evaluate the capacity of a static platelet adhesion assay to detect platelet inhibiting effects of ASA and clopidogrel. The adhesion assay measures several aspects of platelet adhesion simultaneously, which increases the probability of finding conditions sensitive for anti-platelet treatment. Methods With a randomised cross-over design we evaluated the anti-platelet effects of ASA combined with clopidogrel as well as monotherapy with either drug alone in 29 patients with a recent acute coronary syndrome. Also, 29 matched healthy controls were included to evaluate intra-individual variability over time. Platelet function was measured by flow cytometry, serum thromboxane B2 (TXB2)-levels and by static platelet adhesion to different protein surfaces. The results were subjected to Principal Component Analysis followed by ANOVA, t-tests and linear regression analysis. Results The majority of platelet adhesion measures were reproducible in controls over time denoting that the assay can monitor platelet activity. Adenosine 5'-diphosphate (ADP)-induced platelet adhesion decreased significantly upon treatment with clopidogrel compared to ASA. Flow cytometric measurements showed the same pattern (r2 = 0.49). In opposite, TXB2-levels decreased with ASA compared to clopidogrel. Serum TXB2 and ADP-induced platelet activation could both be regarded as direct measures of the pharmacodynamic effects of ASA and clopidogrel respectively. Indirect pharmacodynamic measures such as adhesion to albumin induced by various soluble activators as well as SFLLRN-induced activation measured by flow cytometry were lower for clopidogrel compared to ASA. Furthermore, adhesion to collagen was lower for ASA and clopidogrel combined compared with either drug alone. Conclusion The indirect pharmacodynamic measures of the effects of ASA and clopidogrel might be used together with ADP-induced activation and serum TXB2 for evaluation of anti-platelet treatment. This should be further evaluated in future clinical studies where screening opportunities with the adhesion assay will be optimised towards increased sensitivity to anti-platelet treatment.
Collapse
|
8
|
Characterization of static adhesion of human platelets in plasma to protein surfaces in microplates. Blood Coagul Fibrinolysis 2009; 20:197-206. [DOI: 10.1097/mbc.0b013e328327353d] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
|
9
|
Smyth SS, Cheng HY, Miriyala S, Panchatcharam M, Morris AJ. Roles of lysophosphatidic acid in cardiovascular physiology and disease. Biochim Biophys Acta Mol Cell Biol Lipids 2008; 1781:563-70. [PMID: 18586114 DOI: 10.1016/j.bbalip.2008.05.008] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Revised: 05/27/2008] [Accepted: 05/30/2008] [Indexed: 02/07/2023]
Abstract
The bioactive lipid mediator lysophosphatidic acid (LPA) exerts a range of effects on the cardiovasculature that suggest a role in a variety of critical cardiovascular functions and clinically important cardiovascular diseases. LPA is an activator of platelets from a majority of human donors identifying a possible role as a regulator of acute thrombosis and platelet function in atherogenesis and vascular injury responses. Of particular interest in this context, LPA is an effective phenotypic modulator of vascular smooth muscle cells promoting the de-differentiation, proliferation and migration of these cells that are required for the development of intimal hyperplasia. Exogenous administration of LPA results in acute and systemic changes in blood pressure in different animal species, suggesting a role for LPA in both normal blood pressure regulation and hypertension. Advances in our understanding of the molecular machinery responsible for the synthesis, actions and inactivation of LPA now promise to provide the tools required to define the role of LPA in cardiovascular physiology and disease. In this review we discuss aspects of LPA signaling in the cardiovasculature focusing on recent advances and attempting to highlight presently unresolved issues and promising avenues for further investigation.
Collapse
Affiliation(s)
- Susan S Smyth
- Department of Veterans Affairs Medical Center, Lexington, Kentucky 40511, USA.
| | | | | | | | | |
Collapse
|
10
|
Axelsson S, Hägg S, Eriksson AC, Lindahl TL, Whiss PA. In vitro effects of antipsychotics on human platelet adhesion and aggregation and plasma coagulation. Clin Exp Pharmacol Physiol 2007; 34:775-80. [PMID: 17600556 DOI: 10.1111/j.1440-1681.2007.04650.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
1. Several studies suggest an association between venous thromboembolism and the use of antipsychotic drugs, especially clozapine, but the biological mechanisms are unknown. It has been suggested that antipsychotic drugs enhance aggregation of platelets and thereby increase the risk of venous thrombosis. The purpose of the present study was to examine the effects of clozapine and its main metabolite, N-desmethyl clozapine, as well as olanzapine, risperidone and haloperidol, on platelet adhesion and aggregation and on plasma coagulation in vitro. 2. Blood was collected from healthy subjects free of medication. Platelet adhesion to different protein surfaces and aggregation were measured in microplates. The coagulation methods of activated partial thromboplastin time (APTT) and prothrombin time were performed in platelet-poor plasma. 3. Clozapine was the only compound that increased platelet adhesion and aggregation and shortened APTT. The effect appeared at therapeutic concentrations and was significant but weak. 4. This weak effect of clozapine on haemostasis may explain, in part, the association of this compound and venous thromboembolism.
Collapse
Affiliation(s)
- Stina Axelsson
- Division of Pharmacology, Department of Medicine and Care, Faculty of Health Sciences, Linköping University, Linköping, Sweden
| | | | | | | | | |
Collapse
|