Summary of Doctoral thesis: A study on the effects of allele CYP2C19*2, CYP2C19*3 and some factors related to clopidogrel responsiveness in patients with cerebral

To identify some non- gene CYP2C19 factors related to clopidogrel responsiveness in patients with cerebral infarction. To assess the effect of alleles CYP2C19*2, CYP2C19*3 on the response of clopidogrel in patients with cerebral infarction.

MINISTRY OF EDUCATION  MINISTRY OF NATIONAL  AND TRAINING DEFENSE VIETNAM MILITARY MEDICAL UNIVERSITY DO DUC THUAN  A STUDY ON THE EFFECTS OF ALLELE CYP2C19*2,   CYP2C19*3 AND SOME FACTORS RELATED TO CLOPIDOGREL  RESPONSIVENESS IN PATIENTS WITH CEREBRAL  INFARCTION Major: Neuroscience Code: 9720159 SUMMARY OF DOCTORAL THESIS  WORKS ARE COMPLETED AT VIETNAM MILITARY  MEDICAL UNIVERSITY SUPERVISORS: 1. Assoc. Prof. PHAM DINH TAI 2. Assoc. Prof. TRAN VAN KHOA Reviewer 1: Prof. NGUYEN VAN THONG Reviewer 2: Assoc. Prof. TRAN VAN KHANH Reviewer 3: Assoc. Prof. NGUYEN TRONG HUNG The thesis will be upheld at the thesis evaluation council  at Vietnam Military Medical University at:  …… The thesis can be found at:                   1. National Library                   2. Library of Vietnam Military Medical University INTRODUCTION The necessity for the topic A cerebral infarction is caused by a narrowed artery for a variety  of   causes   but   the   most   common   is   arterial   thrombosis   in   which  platelets   play   a   central   role   in   the   formation   of   blood   clots.  Clopidogrel   is   an   antiplatelet   drug  approved  by  the   World   Stroke  Organization   to   use   thromboprophylaxis   in   patients   with   cerebral  infarction   However,   some   patients   still   have   recurrent   cerebral  infarction while being treated with clopidogrel. Research in the world  show that there are a number of factors affecting the responsiveness,  causing clopidogrel resistance with the rate from 4% to 30%. The  reason   is   that   patients   carry   alleles  CYP2C19*2,   CYP2C19*3  containing   genetic   coding   information   of   CYP2C19   enzyme   (the  enzyme   that   metabolize   clopidogrel   from   precursor   to   active  substance). Some non­gene  CYP2C19  factors related to clopidogrel  responsiveness, such as: age, gender, accompanying drugs, diabetes,  obesity,   increased   HbA1C   or   increased   plasma   protein   C   also  decreased the response of clopidogrel. In Vietnam, research on the  effects   of   these   alleles   and   factors   related   to   clopidogrel  responsiveness   in   patients   with   cerebral   infarction   has   not   been  published. Therefore, we conducted research on the topic "  A study  on the effect of alleles  CYP2C19*2, CYP2C19*3  and some factors  related   to   clopidogrel   responsiveness   in   patients   with   cerebral  infarction" The objectives of the topic ­   To   identify   some   non­   gene   CYP2C19   factors   related   to   clopidogrel responsiveness in patients with cerebral infarction ­ To assess the effect of alleles CYP2C19*2, CYP2C19*3 on   the response of clopidogrel in patients with cerebral infarction 3. Practical significance and contribution of the topic The   topic   gives   information   about   the   rate   of   clopidogrel  resistance   in   cerebral   infarction,   the   rate   of   alleles  CYP2C19*2,  CYP2C19*3 and their effects on the responsiveness of clopidogrel The   topic   provides   information   on   the   relation   between   age,  gender,   BMI,   co­morbidities   (such   as   hypertension,   diabetes,  atherosclerosis, blood biochemical indices (increased CRP; albumin  reduction,   drugs   used   together   with   insulin   or   metformin))   and  clopidogrel   responsiveness   and   since   then   improves   the   use   of  clopidogrel in the prevention on cerebral infarction 4.The structure of the thesis The thesis is presented in 127 pages (excluding references and  appendix) The thesis is divided: Introduction 2 pages, chapter 1: Literature  Review   31   pages,   chapter   2:   Objects   and   Methodology   23   pages,  chapter   3:   Results   36   pages,   chapter   4:   Discussion   32   pages,  Conclusions 2­page and Recommendations 1­page  The thesis includes 48 tables, 19 figures, 1 diagram. Among 176  references   there   are   23   Vietnamese   documents,   153   English  documents, 31 documents in the last 5 years. The appendix includes a  studying medical record, an application for voluntary participation in  the study, ACR / EULAR 2015 diagnostic gout criteria CHAPTER 1: LITERATURE REVEIW 1.1 Cerebral infarction 1.1.1 Definition  1.1.2. Pathogenesis of cerebral infarction and the role of platelets   in cerebral infarction Cerebral   infarction   is   caused   by   a   blocked   brain   artery   that  reduces blood flow to the brain area supplied by that artery. The most  common   cause   is   due   to   arterial   thrombosis   The   process   of  thrombosis occurs gradually over many years and goes through two  stages: Vascular phase, hematology and the chemical change phase  of   the   cell   Platelets   are   mainly   involved   in   blood   vessel   and  hematologic   stages,   play   an   important   role   in   the   formation   and  development   of   thrombosis­atherosclerosis   of   brain   arteries   and  increased   the   activation   of   platelet   after   cerebral   blood   vessel   is  blocked, platelets are aggregated at the micro vessels in the anemia  region, releasing substances acting on blood vessels 1.1.3 Classification of cerebral infarction Classify cerebral infarction according to TOAST 1.1.4. Epidemiology of cerebral infarction The   rate   of   cerebral   infarction   accounts   for   85%   of   the   total  number of strokes, including 17% from infarction caused by heart,  4% from carotid atherosclerosis, 64% from other reasons. Recurrent  cerebral   strokes   account   for   about   25%   of   all   types   of   the   brain  strokes. Using anti­platelet aggregation medication is an important  therapy to prevent recurrent cerebral infarction 1.1.5   Clopidogrel   in   the   treatment   and   prevention   on   cerebral   infarction Clopidogrel is an anti­platelet aggregation drug, approved by the  World   Stroke   Organization   for   the   use   of   prophylaxis   to   prevent  relapse of cerebral infarction 1.2 Factors affecting clopidogrel responsiveness 1.2.1. Pharmacology of clopidogrel Clopidogrel belongs to the thienopyridine group, as a precursor,  after   uptake   metabolism   in   the   liver   it   makes   up   80­85%   of   the  inactive derivatives and 15% of the active ingredient which has anti­ platelet aggregation activity. Clopidogrel is metabolized in the liver  by   enzymes   such   as  CYP2C19,   CYP3A5,   CYP2C9,   CYP2B6,   CYP1A2,  in which the enzyme  CYP2C19  plays the most important  role 1.2.2   The   responsiveness   of   clopidogrel   in   the   prophylactic   treatment of cerebral infarction There   have   been   patients   with   cerebral   infarction   who   used  clopidogrel   but   still   relapse   cerebral   infarction   Because   the  responsiveness of clopidogrel is different in individuals. Therefore,  the authors proposed the notion of poor responsiveness or clopidogrel  resistance 1.2.3. The concept and method of assessing the responsiveness of   clopidogrel ­ Clopidogrel resistance: a situation in which a metabolite from  clopidogrel   uncompleted   blocks   P2Y12   receptors   on   platelet  membranes   The   results   are   measured   by   platelet   aggregation  measurement   test,   based   on   platelet   inhibition   mechanism   of  clopidogrel in patients adhering to clopidogrel ­   The   concept   of   anti­clopidogrel   is   also   understood   as   non­ responsiveness,   high   platelet   activation   after   treatment   or   residual  platelet activation is calculated by the maximum platelet aggregation  after treatment Clopidogrel resistance criteria: platelet aggregation is tested by  LTA­ADP   method     µg/l   >   50%   after   taking   clopidogrel   enough  dose, enough time 1.2.4   Some   non­gene   CYP2C19   factors   related   to   clopidogrel   responsiveness ­ Normally, the elderly has a decline in CYP enzyme system  activity   and   a   high   rate   of   use   of   drugs   metabolized   by   CYP,  suffering   from   comorbid   diseases   which   affect   clopidogrel  metabolism via CYP enzyme system ­ In female ­ to limit bleeding by menstrual by increasing the  likelihood   of   platelet   response,   which   is   affected   by   the   female  hormone and the alternative therapeutic hormones therefore it relates  to clopidogrel response ­   Obesity   increases   leptin,   which   promotes   lipid   oxidation,  stimulates inflammatory factors that increase platelet activation ­  Diabetes  reduces  clopidogrel  response  due  to (1)  increasing  clopidogrel hydrolysis into inactive substance, (2) decreasing activity  of  CYP2C19  enzyme,   (3)   decreasing   absorption   of   clopidogrel   in  gastrointestinal tract, (4) increasing hydrolyzate the active products  of clopidogrel ­ Increased CRP causes platelet adhesion to vascular endothelial  cells   under   normal   flow   conditions   through   P­selectin,   thereby  reducing clopidogrel response Low   plasma  albumin   decreases   clopidogrel   response,   because  low albumin increases the coverage of platelet on surface.  1.2.5   Effect   of   alleles   CYP2C19*2,   CYP2C19*3   on   clopidogrel   responsiveness ­ Clopidogrel exists in precursors form, to affect on anti­platelet  aggregation, they need to be metabolized into active substances, in  which   the   enzyme  CYP2C19  plays   a   major   role  CYP2C19  is   a  polymorphic gene, so the responsiveness of drugs metabolized by the  CYP2C19  enzyme is also diverse. The gene  CYP2C19  is composed  of 2 alleles CYP2C19. The allele CYP2C19 has been identified with  more than 35 variants, each denoted by the numbers *1, *2, *3, *4.  Allele  CYP2C19*1  has   phenotypic   of   enzyme   with   normal  activation Alleles  CYP2C19*2 CYP2C19*3, CYP2C19*4   have enzyme  phenotype that are lost function and inactivation. Meanwhile, allele  CYP2C19*17 gives the enzyme phenotype which increases activation  in drug metabolism.  Research in several Asian countries found that the rate of people  carrying the allele CYP2C19*1 still accounts for the most, followed  by   the   carriers   of   the   allele  CYP2C19*2,  with   a   low   rate   of  CYP2C19*3.  Allele  CYP2C19*17  is   uncommon,   other   alleles   are  rare in Asians ­ There have been many clinical studies proving that the carriers  of   alleles  CYP2C19*2  and  CYP2C19*3  show   poor   response   or  resistance to clopidogrel On March 12, 2010 US FDA issued a warning about reducing  the effect of clopidogrel due to reduced ability to metabolize drugs  into the active form in patients who carry reduced functional alleles  CYP2C19 1.3 Domestic and foreign research 1.3.1. Research in the world Research   of   clopidogrel   responsiveness   have   been   conducted  since   2003,   mainly   in   cardiovascular   patients   using   clopidogrel.  Since   2009,   there   are   studies   of   clopidogrel   responsiveness   in  patients with cerebral infarction such as those by Kim H. et al., Fifi  J.T.et al and Yang J. et al. 2013. These studies found that patients  carrying   reduced   function   alleles   CYP2C19   reduce   clopidogrel  responsiveness. There are also a number of factors such as high age,  female   sex,   obesity,   diabetes,   and   increased   CRP   related   to  clopidogrel responsiveness 1.3.2. Domestic research In Vietnam, there are studies by Do Quang Huan. et al. in 2013  or   Vu   Thi   Thom   et   al   2018   on   clopidogrel   responsiveness   The  studies   had   small   sample,   studying   objects   were   patients   with  coronary   artery   disease   or   healthy   people,   patients   were   given  clopidogrel combined with aspirin. So far, in Vietnam, research on  the factors affecting clopidogrel responsiveness in cerebral infarction  patients has not been published CHAPTER 2: OBJECTS AND METHODOLOGY 2.1 Objects 248 patients with cerebral infarction (genetic testing in 144 first  patients) were treated at Stroke Department, 103 Military Hospital  from May 2017 to August 2018 2.1.1 Inclusion criteria  The patients have enough 4 following criteria: (1) Diagnosed   according   to   the   definition   of   brain   stroke   by  World Health Organization in 1980. (2) There are images of cerebral  infarction   on   computerized   tomography   (3)   Use   clopidogrel   75  mg/day  for   at   least   7 consecutive  days  (4)  Neuroprotective   drugs  with a common regimen: Cerebrolysin 20 ml IV, Piracetam 8 g IV,  Choline alfoscerate 2 g IM 2.1.2 Exclusion criteria (1)   Allergy   to   clopidogrel,   (2)   using   anticoagulants   or   other  antiplatelet drugs which is different from clopidogrel before the study  time   within     weeks   and   during   the   study   period,   (3)   use  thrombolytic drugs to treat cerebral infarction in the acute phase, (4)  being   angioplasty,   stenting   or   endothelial   carotid   dissection   (5)  severe water and electrolyte disturbances, (6) consciousness disorders  or cerebral infarction area greater than 1/3 of the dominant area of the  middle cerebral artery on CT, (7) images of cerebral bleeding on CT,  (8) Hemoglobin  160g/l, (9) Platelets  450  G/l,   (10)   being   hemostatic   coagulopathy   disease,   (11)   have  underlying  diseases:   Myocardial   infarction,   atrial   fibrillation,   heart  failure grade 3 and 4 (12) Hepatitis, cirrhosis, liver cancer. (13) have  glomerular filtration rate  50%, after using clopidogrel 75  11 Table 3.14. Relationship between BMI and clopidogrel resistance BMI (kg/m2) Resistance n = 86  0.05  0.05 > 0.05 Diabetes increases the risk of clopidogrel resistance with OR =  2.03 (95% CI: 1.17­3.51, p  0.05 > 0.05 385.65 ± 109.58 11.56 ± 13.27 357.69 ± 92.17 10.10 ± 4.63 > 0.05 > 0.05 3.36 (0.21;100) 1.8 (0.17;100)  0.05  0.05 > 0.05 The rate of patients using insulin in resistant group  was higher  than in non­ resistance group with p  0.05 Calcium channel blocker 1.22 0.70­2.12 > 0.05 ACE inhibitor 0.99 0.57­1.67 > 0.05 Insulin 3.59 1.36­9.50  0.05 Metformin 1.00 0.42­2.34 > 0.05 Using insulin increases the risk of clopidogrel resistance to OR  = 3.59 (95% CI: 1.36­9.49; p