Analysis of the association between polymorphisms within genes which regulate fibrinolysis and extracellular matrix integrity with the effects of ischemic stroke therapy with recombinant tissue plasminogen activator

Ishemijski moždani udar (IMU) nastaje usled okluzije krvnog suda embolusom, ili trombozom in situ u određenim regionima mozga. Centralna zona ishemije, sa terapijskog aspekta, od početka je izgubljena, ali oko nje se nalazi zona penumbre u kojoj su neuroni poremećene funkcije, ali strukturalno intaktni i gde je još uvek moguć oporavak njihove funkcije. Terapija izbora u akutnoj fazi IMU je intravenska primena rekombinovanog tkivnog aktivatora plazminogena (rtPA). Uprkos činjenici da samo mali broj pacijenata sa akutnim IMU primi rtPA, pacijenati u terapijskom prozoru za primenu iste, imaju veće dugoročno preživljavanje i niže stope mortaliteta, kao i bolji funkcionalni oporavak nakon IMU. Sa druge strane, kod određenog broja pacijenata koji su primili rtPA, dolazi do hemoragijske transformcije (HT) ili simptomatske intrakranijalne hemoragije (sICH), najozbiljnijih komplikacija ove terapije povezanih sa visokom stopom morbiditeta i mortaliteta. Razlozi zašto neki pacijenti bolje, a drugi lošije odgovore na rtPA terapiju su brojni, ali i dalje nisu do kraja razjašnjeni. Genski polimorfizmi mogu biti u osnovi različitog nivoa ekspresije gena, ili aktivnosti genskog produkta, pa posredno mogu uticati na fiziologiju i funkcionalnost ćelija, ali i na odgovor na primenjenu terapiju. Cilj ove disertacije bio je da se kod osoba sa IMU lečenim rtPA terapijom utvrdi učestalost genotipova i alela izabranih polimorfizama u genima koji regulišu fibrinolizu (PAI-1 i ACE) i intergritet vanćelijskog matriksa (MMP-2, MMP-9 i TIMP-2), kao i da se analizira povezanost ispitivanih polimorfnih genskih varijanti sa efikasnošću i pojavom hemoragijskih komplikacija nakon rtPA terapije. Metod: Istraživanje je sprovedeno po tipu hibridne panel studije. Studija je sprovedena od avgusta 2016. godine do avgusta 2018. godine u Specijalnoj bolnici za cerebrovaskularne bolesti ,,Sveti Sava’’ u Beogradu, dok su molekularno-genetička istraživanja obavljena na Institutu za humanu genetiku Medicinskog fakulteta Univerziteta u Beogradu. Inicijalna studija preseka je uključila sve pacijente koje su imali IMU lečen rtPA terapijom prvih šesnaest meseci studije i obuhvatila je 94 pacijenta. Finalno, u studiju je uključeno 166 konsekutivna pacijenta sa IMU lečenih rtPA terapijom. Funkcionalni oporavak kod svih bolesnika praćen je preko modifikovanog Rankin skora (mRS). MRS je određivan svakom pacijentu po otpustu iz bolnice i tri meseca nakon IMU. Efikasnost rtPA terapije je procenjivana na osnovu povoljnog funkcionalnog oporavka, definisanog mRS skorom 0 ili 1, tri meseca nakon IMU. Svim pacijentima 24h nakon rtPA terapije urađen je kontrolni CT snimak. Prisustvo hemoragijske transformacije na kontrolnom CT snimku definisano je u skladu sa ECASS II kriterijumima...Ischemic stroke (IS) occurs due to an embolus or thrombosis causing vascular occlusion in situ in certain brain parts. From the therapeutic point of view, the central zone of ischemia is irrelevant, since nerve cells cannot be saved. However, it is surrounded by a penumbra, an area where the neurons are functionally disturbed, but structurally intact, with the possibility for the recovery of their function. The therapy of choice in the acute phase of IS is an intravenous administration of recombined tissue plasminogen activator (rtPA). Even though only a small number of patients with acute IS receive rtPA, patients within the therapeutic window for its application have higher long-term survival and lower mortality rates, as well as better functional recovery. On the other hand, a certain number of patients who have received rtPA develop symptomatic intracranial hemorrhage (sICH) or hemorrhagic transformation (HT), as the most severe complications of this therapy - associated with high morbidity and mortality rates. The reasons why some patients respond to rtPA therapy better, and others worse are numerous, but still not fully elucidated. Gene polymorphisms could have different effects on gene expression, or the activity of a gene product, and can indirectly affect the physiology and functionality of cells, and also the response to applied therapy. This study aimed to determine the frequency of genotypes and alleles of selected polymorphisms in genes that regulate fibrinolysis (PAI-1 and ACE) and extracellular matrix integrity (MMP-2, MMP-9, and TIMP-2) in individuals with IS treated with rtPA therapy, as well as to analyze the association of the studied polymorphic gene variants with the rtPA efficacy and occurrence of hemorrhagic complications after rtPA therapy. Method: This is a hybrid panel study. It was conducted from August 2016 to August 2018 at the Special Hospital for Cerebrovascular Diseases "St. Sava" in Belgrade, while molecular genetic researches were performed at the Institute of Human Genetics of the Medical Faculty of the University of Belgrade. The initial cross-sectional study included all patients who had IS treated with rtPA therapy during the first sixteen months of the study and involved 94 patients. Finally, 166 consecutive patients with IS treated with rtPA therapy were enrolled in the study. Functional recovery in all patients was estimated by a modified Rankin score (mRS). MRS for each patient was determined at hospital discharge and 3 months after IS. The efficacy of rtPA therapy evaluation was based on the favorable functional recovery, defined by mRS score 0 or 1, three months after IS. All patients underwent a control CT scan 24 hours after rtPA therapy. The presence of HT on the control CT scan was defined in accordance with the ECASS II criteria. In case of a sudden worsening of the neurological condition, a control CT scan was done urgently..