Hypercholesterolemia is a determining factor for the development of atherosclerosis, which is considered the main cause of cardiovascular diseases. In Brazil, as in most developed countries, cardiovascular diseases are the leading cause of death. Several mechanisms are involved in the development of atheromatous plaque thus the purpose of this study was to evaluate the association between hypercholesterolemia and inflammatory, vascular, and oxidative biomarkers as well as to develop and validate an analytical method for the automated measurement of nitrite, a metabolite of the oxide oxide (NO) in plasma samples. In the first phase of this study an analytical method for automated measurement of plasma nitrite was developed and validated. This method was precise (r2=0,9998, P<0,001), linear, simple, inexpensive, and applicable to routine monitoring. In phase 2, inflammatory, vascular and oxidative markers were assessed. The groups were: group with hypercholesterolemia (LDL-C ≥ 160 mg / dl) and normocholesterolemic group (LDL-C ≤ 130 mg / dL). Results showed that levels of total cholesterol, LDL-C, HDL-C, triglycerides, apolipoprotein A, apolipoprotein B, advanced oxidation protein products (AOPP), interleukin-6 (IL-6) and D-dimer were significantly higher in hypercholesterolemic patients, while levels of thiol grouping (-SH) and nitrate / nitrite (NOx) were lower in this group. There were also significant correlations for LDL-C and IL-6 (r = 0.693, P <0.0001), LDL-C and NOx (r = -0.314, P <0.05) and LDL-C and - SH (r = -0.327, P <0.05). Thus, hypercholesterolemia promotes increased oxidative stress, inflammation, and fibrinolysis in atherosclerosis. / A hipercolesterolemia é um fator determinante para o desenvolvimento da aterosclerose, que é considerada a principal causa de doenças cardiovasculares. No Brasil, assim como na maior parte dos países desenvolvidos, as doenças cardiovasculares representam a principal causa de morbimortalidade. Vários mecanismos estão envolvidos no desenvolvimento da placa de ateroma, assim o objetivo deste estudo foi avaliar a associação entre a hipercolesterolemia e biomarcadores inflamatórios, oxidativos e vasculares, bem como desenvolver e validar um método analítico automatizado para a mensuração de nitrito, um metabólito do óxido nítrico (NO), em amostras de plasma. Na fase 1 deste estudo, foi desenvolvido e validado um método analítico automatizado para dosagem de nitrito plasmático. Este método foi preciso, linear (r2=0,9998, P<0,001), simples, de baixo custo e aplicável a rotina laboratorial. Na fase 2, foram avaliados marcadores inflamatórios, oxidativos e vasculares. Os grupos estudados foram: grupo hipercolesterolêmicos (LDL-C ≥ 160 mg/dL) e normocolesterolêmicos (LDL-C ≤ 130 mg/dL). Os resultados demonstraram que níveis de colesterol total, LDL-C, HDL-C, triglicérides, apoliproteína A, apoliproteína B, produtos protéicos da oxidação avançada (AOPP), interleucina-6 (IL-6) e D-dímero foram significativamente maiores nos pacientes hipercolesterolêmicos, enquanto os níveis de grupamento tiol (-SH) e nitrato/nitrito (NOx) foram inferiores neste grupo. Foram ainda observadas correlações significativas para o LDLC e IL-6 (r = 0,693, P <0,001), LDL-C e de NOx (r = -0,314, P <0,05) e LDL-C e SH (r = - 0,327, P <0,05). Dessa forma, a hipercolesterolemia promove o aumento do estresse oxidativo, inflamação e fibrinólise durante a aterosclerose.

Background: The Framingham Study from 1988 showed a heavy impact of diabetes mellitus (DM) on the risk and prognosis of cardiovascular disease (CVD). Several other studies have confirmed that DM is an independent risk factor for coronary heart disease (CHD) and that patients with DM have a poor prognosis. However, the strength of DM as a risk factor is debated. Some studies indicate that DM, as a risk factor for a coronary event, is comparable to already known or established CHD. Also, mechanisms of how diabetes increases the CVD risk are under intensive research. A novel risk factor such as altered fibrinolysis is one of the potential mechanisms explaining the heavy cardiovascular burden in diabetes. Hypofibrinolytic changes can be seen in individuals with metabolic syndrome, insulin resistance, and obesity as well as in patients with manifest diabetes or manifest CHD. Methods: This dissertation is divided in three parts; epidemiological, etiological and interventional. Papers I and II are epidemiological, population based retrospective studies which compare time trends in myocardial infarction and stroke morbidity and mortality between patients with or without diabetes. Papers III and IV have an etiological approach to the fibrinolytic system and CVD risk both in patients with or without diabetes. Paper V is the interventional part of this thesis studying if intensive insulin treatment can improve fibrinolysis in patients with high CVD risk. Results: The incidence and mortality from myocardial infarction and stroke have declined in the counties of Västerbotten and Norrbotten in Northern Sweden. Unfortunately, the subgroup with patients with diabetes and myocardial infarction (MI) in Paper I did not benefit from these favorable trends over the study period. For stroke, this is for the first time declining incidence has been reported in this population. Incidence of first-ever stroke decreased for non-diabetic men with a yearly change of -0.8 percent (p-value  &lt;0.001), and for diabetic women with a yearly change of -1.5 percent (p-value=0.012). Recurrent stroke incidence declined highly significant, p-value  &lt;0.001, for non-diabetic men and women and for diabetic women with a yearly change of -1.5, -2.7, and -5.4 percent, respectively. For diabetic men a non-significant decline of -1.0 percent (p-value=0.28) in stroke incidence was seen. Paper II showed that women with diabetes had decreased incidence for stroke but not men with diabetes. Also, reduced mortality from stroke was found in all patients except for diabetic women with first ever stroke. Patients with diabetes have altered fibrinolysis compared to individuals with normal glucose metabolism. Also, patients with prior MI manifest a hypofibrinolytic stage with low tissue-type plasminogen activator (tPA) activity and high levels of plasminogen activator inhibitor-1 (PAI-1) and fibrinogen. Paper III showed a significant association between decreased tPA activity and increased fibrinogen levels in patients with a first MI when examined 3 months after the event. The results persisted even after adjustment for traditional risk factors and variables mirroring the insulin resistance syndrome and were significant in the whole study group of subjects with MI as well as for men alone. Paper IV, a 10 year follow-up study, showed that in patients with diabetes, tPA-activity significantly predicted the presence of sign(s) of lower extremity arterial disease (LEAD) at the baseline and at the 10-year follow-up. In addition, tPA-mass at the 10-year follow-up was associated with signs of LEAD. Baseline age, hypertension, and HbA1c were independently associated with sign(s) of LEAD at 10 years. This long-term study supports previous findings of a significant association between asymptomatic LEAD and tPA-activity. Thus, tPA-activity may be an early marker of LEAD, although the mechanism of this relationship remains unclear. Several studies report conflicting results regarding benefits and disadvantages of intensive insulin treatment. ORIGIN trial was an international multicenter trial studying effects of intensive insulin treatment on CVD. This thesis reports a Swedish sub-study of ORIGIN trial examining effects of insulin treatment on fibrinolysis. The allocation to insulin treatment did not significantly affect the studied fibrinolytic markers or von Willebrand factor (VWF) compared to the standard treatment. Log mean delta values between baseline and end of study increased significantly for tissue plasminogen activator activity (tPAact) and tPA/PAI-1 complex. For plasminogen activator inhibitor-1 (PAI-1), tPA antigen (tPAag) and VWF no significant differences were found. Within-group analysis during the whole study period revealed significant changes for tPA/PAI-1 complex, tPA antigen, and VWF in the insulin treatment group but no significant changes in the standard treatment group. The hypothesis that allocation to insulin treatment would improve the levels of markers of fibrinolysis or VWF compared to standard glucose lowering treatment could not be verified.   Conclusion: This dissertation shows that patients with diabetes still have a heavy cardiovascular disease burden with increased risk for MI and stroke compared to individuals with normal glucose metabolism. This cardiovascular burden also includes increased morbidity, mortality, and poorer long-term prognosis. The fibrinolytic system has an impact on cardiovascular disease and this thesis has shown that patients with diabetes have unfavorable changes in their fibrinolysis and that alterations in fibrinolysis can predict future peripheral artery disease. However, intensive insulin therapy did not appear to affect this system to the extent of resulting in reduced cardiovascular morbidity. / Diabetes bakgrund: Diabetes Mellitus är en av de vanligaste kroniska sjukdomarna i världen. Diabetesförekomsten har ökat påtagligt de senaste årtiondena. Ökningen beror på ökat insjuknande på grund av livsstilsförändringar med minskat fysisk aktivitet och ökad övervikt och även på grund av förbättrad diagnostik. Även förbättrad sjukvård med ökad överlevnad hos patienter med diabetes samt fler andel äldre ökar andelen diabetes patienter i befolkningen. Enligt WHO har antalet patienter med diabetes stigit från 30 miljoner år 1985 till 171 miljoner år 2000 då uppskattningsvis 4,6 % av vuxenbefolkning har diabetessjukdomen. Majoriteten, ca 80 % har diabetes typ 2. WHO:s prognos visar fortsatt kraftig ökning av diabetes med ca 550 miljoner drabbade år 2030. Majoriteten av denna förändring förklaras av diabetes typ 2 som i framtiden beräknas utgöra 90-95% av all diabetes. Diabetes är fortsatt den viktigaste bakomliggande orsaken till terminal njursvikt i industriländer och en av de vanligaste orsakerna till blindhet i världen. Diabetes innebär en kraftigt ökad risk för hjärt- och kärlsjukdomar. Patienter med diabetes som drabbats av hjärt- och kärlsjukdom såsom hjärtinfarkt eller stroke har ofta sämre prognos, både akut och på långsiktigt, jämfört med patienter utan diabetes. På grund av att diabetes är en kronisk sjukdom med många, ofta svåra och kostsamma, komplikationer står diabetesrelaterade sjukvårdskostnader för en betydande del av totala de sjukvårdskostnaderna i världen varierande mellan 2,5 – 25 % av olika länders sjukvårdsbudget. Diabetes och risk för hjärt- och kärlsjukdomar: De klassiska risk-faktorerna för hjärt- och kärlsjukdomar är ålder, rökning, högt blodtryck, högt kolesterol, låg fysisk aktivitet/övervikt och ärftlighet. Lägger man till diabetes till dessa riskfaktorer får man påtagligt ökad risk för kärlsjukdomar som hjärtinfarkt, stroke och perifer kärlsjukdom. Mekanismerna bakom denna överrisk av diabetes är fortfarande åtminstone till viss del oklara och aktuella för intensiv forskning och debatt. Sannolikt har tiden före diabetesdiagnosen, prediabetes, betydelse då vi vet att vid tidpunkt för diagnos har patienterna med typ 2 diabetes haft störd sockeromsättning varierande länge, oftast sannolikt flera år. Andra tänkbara diabetesrelaterade orsaker för ökad hjärt- och kärlsjuklighet kan vara kronisk inflammation, blodets störda levringsfunktion (hypofibrinolys), nedsatt funktion i blodkärlen (endoteldysfunktion), ogynnsam blodfetts-profil, kroniskt höga insulinnivåer och även sannolikt direkt skadlig effekt av det höga sockret på flertal celler och organ i kroppen. Framtidens behandlingsmöjligheter: Aktuella behandlingsriktlinjer betonar vikten av att betrakta individer med diabetes som högriskpersoner avseende hjärt- och kärlsjukdomar oavsett förekomst av känd kärlsjukdom. Sjukvården ska primärpreventivt intensivbehandla de traditionella riskfaktorerna hos individer med diabetes. Det är dock uppenbart att personer även med helt optimalt behandlade riskfaktorer som blodtryck och kolesterol och även optimal sockerkontroll har fortsatt högre risk för hjärt- och kärlsjukdomar, så kallad residual risk, jämfört med personer utan diabetes. Det är viktigt att i framtiden försöka klargöra vilka faktorer som utgör denna residual risk och utveckla behandlingsmöjligheter mot dessa faktorer. Det är sannolikt av största vikt att tidigt identifiera individer med störd sockeromsättning och risk för utveckling av diabetes. Sjukvården bör sträva efter att minimera de negativa effekterna av prediabetes och förebygga progress till manifest diabetes. Avhandlingens syfte: Att kartlägga hur effektiv den traditionella riskfaktorbehandlingen har varit i att förebygga hjärt- och kärlsjukdomar, särskilt hjärtinfarkt och stroke, hos patienter med diabetes. I avhandlingen  studeras närmare en av de icke traditionella riskfaktorerna nämligen i det blodproppsupplösande systemet, fibrinolysen. Det är numera välkänt att diabetes i sig påverkar fibrinolyssystemet ogynnsamt och att vissa diabetesläkemedel kan påverka fibrinolysen gynnsamt. Vi har studerat om förändringar i fibrinolysen kan prediktera perifer kärlsjukdom hos patienter med diabetes och om intensiv insulinbehandling kan påverka detta fibrinolyssystem. Resultat: Avhandlingen visar att insjuknandet och dödlighet i hjärtinfarkt och stroke har minskat i Västerbotten och i Norrbotten. För stroke var det första gången ett minskat insjuknande kunde rapporteras för denna population. Tyvärr har inte patienter med diabetes och hjärtinfarkt fått ta del av dessa gynnsamma trender under studerad tid. För stroke har kvinnor med diabetes fått minskat insjuknande men inte män med diabetes. Strokestudien kunde också redovisa minskat dödlighet i stroke för alla patienter utom kvinnor med diabetes med en förstagångs insjuknande i stroke. Patienter med diabetes har påverkad fibrinolys jämfört med personer med normal glukosmetabolism. Även patienter med tidigare hjärtinfarkt uppvisar ett hypofibrinolytisk tillstånd med låg tPA-aktivitet och höga nivåer av PAI-1 och fibrinogen. Arbete III visade en association mellan låg tPA-aktivitet och höga nivåer av fibrinogen hos patienter med förstagångs hjärtinfarkt. Detta samband kvarstod även efter justering med traditionella riskfaktorer. Arbete IV, en 10 års uppföljning visade hos patienter med diabetes att tPA-aktivitet kan prediktera förekomsten perifer kärlsjukdom vid baslinjen och även vid 10-års uppföljning. Dessutom var tPA-mass vid 10-års uppföljning associerad med perifer kärlsjukdom. Av de traditionella riskfaktorerna var ålder, hypertension och HbA1c vid studiestart oberoende associerade med förekomst av perifer kärlsjukdom vid 10 års uppföljning. Denna långtidsstudie stöder tidigare fynd av ett signifikant samband mellan asymtomatisk perifer kärlsjukdom och tPA-aktivitet. Sålunda kan tPA-aktivitet vara en tidig markör av perifer kärlsjukdom, även om, den bakom liggande mekanismen för detta är fortfarande oklart. Flera större studier rapporterar motstridiga resultat beträffande för- och nackdelarna med intensiv insulinbehandling. ORIGIN studien var en internationell multicenterstudie som undersökte effekterna av intensiv insulinbehandling på hjärt- och kärlsjukdomar. I arbete V med ORIGIN-studiens svenska kohort undersöktes effekterna av insulinbehandling på fibrinolys. Randomisering till insulinbehandling hade ingen signifikant effekt på de studerade fibrinolytiska markörerna eller von Willebrand faktorn VWF jämfört med standardbehandling. Logaritmerade medeldeltavärden mellan baslinjen och studie slutet ökade signifikant för tPA-aktivitet och tPA/PAI-1-komplexet. För PAI-1, tPA-antigen och för VWF kunde inga signifikanta skillnader visas. Inom-gruppsanalys över hela studieperioden visade signifikanta förändringar för tPA/PAI-1-komplexet, tPA-antigen och VWF i insulingrupp men inga signifikanta förändringar för patienter med standardbehandling. Hypotesen att randomisering till insulinbehandling skulle förbättra nivåerna av fibrinolysfaktorer eller VWF jämfört med standardbehandling kunde inte verifieras Konklusion: Denna avhandling visar att patienter med diabetes har fortsatt ökad risk för hjärtinfarkt och stroke jämfört med individer med normal sockeromsättning. Denna överrisk betyder för patienter med diabetes en ökad risk för insjuknande, svårare sjukdomstillstånd och sämre prognos med ökad risk för återinsjuknande samt även högre dödlighet både på kort och lång sikt. Även andra aktuella studier rapporterar en fortsatt hjärt- och kärlrelaterad överrisk hos patienter med diabetes. Fibrinolyssystemet har betydelse för hjärt- och kärlsjukdomar och denna avhandling visar att patienter med diabetes har ogynnsamma förändringar i sin fibrinolys, så kallad hypofibrinolys. Intensiv insulinbehandling förefaller inte påverka fibrinolysen till den grad att minskad hjärt- och kärlsjuklighet kan ses.

Le facteur 4 plaquettaire (PF4/CXCL4) est un tétramère constitué de quatre sous-unités identiques de 7,8 kDa qui est libéré en grande quantité par les plaquettes lors de l’hémostase primaire (ensemble des phénomènes permettant un colmatage initial d’une lésion vasculaire). L’étude de la formation d’un caillot de fibrine en présence de PF4 montre une augmentation de la turbidité finale du caillot : le PF4 modifie le réseau formé. Etant donné que la plupart des acteurs de la fibrinolyse se lie au caillot de fibrine et que le PF4 modifie sa structure, nous avons pensé qu’il serait intéressant de rechercher si le PF4 influençait aussi la fibrinolyse. La lyse d'un caillot est effectuée par la plasmine issue de l'activation du plasminogène par son activateur d’origine tissulaire (t-PA) en présence d’un cofacteur qui n'est autre que la fibrine. Nous avons étudié la lyse de caillots de plasma, obtenus par activation de la cascade de la coagulation, en condition statique et à l'aide d'un modèle de thrombose artérielle (système Chandler loop). Dans les deux cas, une diminution du temps de demi-lyse a été observée en présence de PF4. Cependant, la lyse de caillots préparés par simple ajout de thrombine sur du fibrinogène ne permet pas de retrouver cet effet du PF4. Ceci suggère que l’influence du PF4 sur la structure du caillot n’est pas à l’origine de l’effet sur sa lyse et que le PF4 n’influence pas (ou très peu) l'activation du plasminogène, ainsi que l'activité de la plasmine résultante. Cette hypothèse a été confirmée par l’étude de l’activité amydolytique du t-PA et de la plasmine (quelle soit ajoutée ou générée). En système purifié, les inhibiteurs plasmatiques de la fibrinolyse sont absents. Les deux principaux sont l'inhibiteur de l'activateur du plasminogène de type 1 (PAI-1) et l’α2-antiplasmine (α2-AP). La lyse de caillots préparés à partir de plasma déficient en α2-AP montre une diminution du temps de demi-lyse en présence de PF4 (comme pour le plasma normal), alors qu’avec le plasma dépourvu de PAI-1 le temps de demi-lyse n'est plus influencé. De plus, l’ajout de PAI-1 dans le système purifié entraine une diminution du temps de demi-lyse en présence de PF4. Ceci suggère que le PF4 prévient directement ou indirectement l'inhibition du t-PA par PAI-1. L’étude de la cinétique d'inhibition de l’activité amidolytique du t-PA par le PAI-1, la détermination de la stœchiométrie de cette inhibition, et l’analyse de ces cinétiques par immuno-empreinte montrent que le PF4 est un modulateur de la fibrinolyse qui agit en retardant la formation d'un complexe initial entre le t-PA et le PAI-1. Cette nouvelle fonction du PF4 est cohérente, et vient en complément de celle décrite récemment d’inhibiteur de l'activation du TAFI. / Platelet factor 4 (PF4/CXCL4) is a tetramer constituted of four identical 7,8 kDa subunits released in large quantities by platelets during primary heamostasis (allowing initial clogging of a vascular injury). Study of fibrin clot formation in the presence of PF4 shows an increase of the final clot turbidity: PF4 modifies the formed network. Given that most fibrinolysis actors are bound to the fibrin clot and that PF4 modifies its structure we thought it would be interesting to investigate if PF4 also influences fibrinolysis. Clot lysis is performed by plasmin originating from activation of its precursor by tissue plasminogen activator (t-PA) with fibrin itself as cofactor of the reaction. We have studied lysis of plasma clots formed by activation of the coagulation cascade in static condition and in a Chandler loop model mimicking arterial thrombosis. Half-times of lysis decreased in the presence of PF4 in both systems. However, PF4 had no longer detectable influence on the half-time of lysis with clots formed by direct addition of thrombin on purified fibrinogen. Observation suggested that the observed decrease of the half-time of lysis induced by PF4 did not originate from its influence on fibrin clot formation and that PF4 had little effect if any on plasminogen activation or plasmin activity. We confirmed this hypothesis by comparing amydolytic activities of t-PA and plasmin (added or generated through plasminogen activation). In purified system, fibrinolysis inhibitors are absent. The two main inhibitors are plasminogen activator inhibitor-1 (PAI-1) and α2-antiplasmin (α2-AP). Lysis of clots obtained from α2-AP deficient plasma showed a decrease of the half-time of lysis in the presence of PF4 (as in normal plasma), whereas in PAI-1 deficient plasma half-time of lysis was unchanged. Moreover if PAI-1 was added to the purified system, half-time of lysis decreased in the presence of PF4. Observations therefore suggested that PF4 prevented directly or indirectly t-PA inhibition by PAI-1. Kinetics of the amidolytic activity of t-PA inhibition by PAI-1 in the presence or not of PF4, determination of its stoichiometry and Western blot analysis of these inhibition kinetics revealed that PF4 is a fibrinolysis modulator which delays formation of the initial (Michaelis) complex between t-PA and PAI-1. This new feature of PF4 is consistent and complementary with its recently described role as a modulator of TAFI activation.

The aim of this thesis was to study the biomarker homocysteine and other novel potential vascular risk factors for dementia. In an out-patient based study of a cohort of 926 consecutive subjects referred to our Memory Unit during 1996―2000, serum-folate was lower and total plasma homocysteine (tHcy) and serum methyl malonate were higher in subjects being prescribed with B12. In the subgroup diagnosed with dementia and with a positive family history of dementia, tHcy was higher than in the subgroup diagnosed as non-demented. It is necessary to supplement subjects with vitamin B12 deficiency with B12, but our results indicate that it is not sufficient with B12 alone because this gives rise to intracellular folate deficiency. We also found indications of a genetic component in dementia because tHcy was higher in the group with a positive family history of dementia. These findings prompted further studies of homocysteine metabolism. The frequency of mutations in the gene for folate receptor-α (FOLR-1), and the fibrinolytic pattern in dementia and non-dementia were studied in the two cohorts DGM (n=300) and AS (n=389). The DGM cohort is a consecutive series of subjects attending our Memory Care Unit for investigation of suspected cognitive problems or dementia between 2003 - 2007. The AS (= active seniors) cohort comprises retired, apparently healthy subjects from central Sweden, actively participating in study circles. A rare haplotype in the FOLR-1, with mutations in two nearby loci, was discovered, possibly associated with lower serum-folate and higher tHcy concentrations and was more frequent in the DGM group. The transport of folate to the CSF was studied in the DGM-cohort. Dementia with a vascular component was associated with a lower CSF to serum folate ratio indicative of reduced transport of folate to the CSF and further to the brain. The vascular endothelial derived fibrinolytic markers tPA, tPA/PAI-1-complex, and vWF were not only higher in vascular dementia (VaD) but also in Alzheimer’s Disease (AD) when compared to the AS group. The impaired fibrinolytic activity in both vascular dementia and in AD is a novel finding, signifying a vascular component in the development of dementia. In conclusion we found that both hereditary and nutritional background factors were linked to dementia and furthermore that a dysregulated fibrinolysis was linked to both VaD and AD.

<p>Tromboza danas, u većini razvijenih zemalja, predstavlja vodeći uzrok obolevanja i umiranja. Poslednjih godina veoma aktuelna su istraživanja venskog tromboembolizma, obzirom da je incidenca ovog oboljenja 2/1000 osoba godi&scaron;nje, a njegov razvoj posledica udruženog delovanja vi&scaron;e genetskih i stečenih faktora rizika. &Scaron;to preciznije prepoznavanje i sagledavanje &scaron;to većeg broja ovih faktora osnovni je cilj u borbi, kako protiv prve epizode venske tromboze, tako i protiv recidiva ove bolesti. Brojni faktori rizika već su prepoznati kao sastavne karike patofiziolo&scaron;kog lanca venskog trombotskog procesa, ali je evidentno da otkrića mnogih od njih tek predstoje. Među najaktulenijim istraživanjima na ovom polju nalazi se i ispitivanje uloge poremećaja fibrinoliznog mehanizma u venskoj tromboembolijskoj bolesti. Iako su već pruženi dokazi da suprimirana fibrinolizna aktivnost povećava rizik od nastanka ovog oboljenja, jo&scaron; uvek postoje brojna otvorena pitanja, koja se pre svega odnose na ulogu pojedinačnih činilaca fibrinoliznog mehanizma u venskoj trombozi, kao i na globalnu ulogu fibrinoliznog mehanizma u različitim tipovima i lokalizacijama venske trombotske bolesti. Pored toga, ispitivanje uticaja pojedinih genskih mutacija na pojadinačne činioce fibrinoliznog mehanizma, njegovu globalnu funkcionalnost i posredno na rizik za nastanak venske tromboze, takođe zaokuplja pažnju stručne javnosti, obzirom na nekonzistentnost rezultata dobijenih studijama koje se bave ovom problematikom. Cilj ovoga istraživanja je ispitivanje kako globalne funkcionalnosti fibrinoliznog mehanizma, tako i njegovih pojedinačnih činilaca, kod bolesnika sa različitim tipovima i lokalizacijama venske tromboze i poređenje ovih parametara sa njihovim vrednostima u zdravoj populaciji. Pored toga, cilj istraživanja je i ispitivanje zastupljenosti 4G/5G PAI-1 polimorfizma kod bolesnika sa venskom trombozom u poređenju sa zdravim osobama. Ispitivanu grupu je sačinjavalo 100 bolesnika koji su doživeli trombozu dubokih vena a kontrolnu grupu je činilo 100 zdravih ispitanika, koji nikada nisu imali trombozni incident. Iz ispitivanja su isključene: osobe sa prethodno dokazanim poremećajem hemostaznog mehanizma, osobe koje uzimaju lekove za koje se zna da mogu imati uticaja na hemostazni mehanizam, osobe koje su imale akutnu bolest u momentu uzorkovanja krvi ili 6 nedelja pre toga, osobe sa malignitetom, trudnice, osobe sa težim du&scaron;evnim bolestima, bolestima jetre i bubrega, autoimunim bolestima, ispitanici koji su odbili da potpi&scaron;u pristanak informisanog ispitanika. Kao test za procenu globalne funkcionalnosti fibrinoliznog mehanizma kori&scaron;teno je euglobulinsko vreme lize koaguluma, dok su od pojedinačnih činilaca određivani: tkivni aktivator plazminogena (t-PA) i trombinom aktivi&scaron;ući fibrinolizni inhibitor (TAFI) - ELISA metodom, kao i inhibitor aktivatora plazminogena-1 (PAI-1) - metodom hromogenog substrata. Genetskim ispitivanjem je utvrđivano prisustvo PAI-1 4G/5G genskog polimorfizma. Prema rezultatima istraživanja kod 56% bolesnika bila je prisutna spontana venska tromboza, dok je 44% njih imalo trombozu provociranu jednim od priznatih faktora rizika. U odnosu na lokalizaciju venskog tromboznog procesa proksimalna venska tromboza bila je prisutna kod 63% bolesnika, izolovana distalna venska tromboza kod 29% bolesnika, a atipično lokalizovana venska tromboza kod 8% bolesnika. Posmatrajući zastupljenost pojedinih faktora rizika uočili smo da je značajno vi&scaron;i procenat osoba sa hipertenzijom bio prisutan u grupi bolesnika sa primarnom trombozom dubokih vena u odnosu na grupu bolesnika sa provociranom trombozom dubokih vena (61% vs.16%; p=0.000). &Scaron;to se funkcionalnosti fibrinoliznog mehanizma tiče, prema na&scaron;im rezultatima bolesnici koji su doživeli trombozu dubokih vena imaju značajno duže vreme lize koaguluma, odnosno suprimiranu funkcionalnost fibrinolize u poređenju sa zdravim kontrolama (204.34&plusmn;51.24 vs. 185.62&plusmn;42.30; p=0.011), a kada posmatramo podgrupe bolesnika u odnosu na lokalizaciju i vrstu venske tromboze uočavamo da podgrupa bolesnika sa izolovanom distalnom venskom trombozom ima značajno duže euglobulinsko vreme lize koaguluma u odnosu na kontrolnu grupu (218.32&plusmn;41.12 vs.185.62&plusmn;42.30: p=0.001), kao i bolesnici koji su imali provociranu vensku trombozu u poređenju sa kontrolama (208.18&plusmn;48.53 vs. 185.62&plusmn;42.30; p=0.018). Ispitivanjem pojedinačnih komponenti fibrinoliznog mehanizma do&scaron;li smo do rezultata da bolesnici koji su doživeli venski trombozni incident imaju značajno vi&scaron;e koncentracije TAFI u poređenju sa osobama koje nikada nisu imale vensku trombozu (19.70 ng/ml &plusmn; 5.17 vs.17.13 ng/ml &plusmn; 4.25; p=0.001). Poređenjem bolesnika sa provociranom trombozom dubokih vena i kontrolnih ispitanika uočili smo da bolesnici iz ove podgrupe imaju značajno vi&scaron;e vrednosti plazminogena u poređenju sa zdravim osobama (127.14 % &plusmn; 27.73 vs.117.09 % &plusmn; 24.49; p= 0.044), kao i značajno vi&scaron;e koncentracije t-PA (20.02 ng/ml &plusmn; 11.07 vs. 16.78 ng/ml &plusmn; 8.08; p=0.042). &Scaron;to se tiče TAFI, bolesnici sa distalnom trombozom dubokih vena u poređenju sa kontrolama (20.72 ng/ml &plusmn; 4.96 vs.17.13 ng/ml &plusmn; 4.25; p=0.001), kao i bolesnici sa proksimalnom trombozom dubokih vena u poređenju sa kontrolama (19.37 ng/ml &plusmn; 5.33 vs.17.13 ng/ml &plusmn; 4.25; p=0.013) imaju značajno vi&scaron;e koncentracije TAFI. Koncentracija ovog inhibitora fibrinoliznog procesa značajno je veća i kod bolesnika sa provociranom trombozom dubokih vena u poređenju s zdravim osobama (19.93 ng/ml &plusmn; 3.97 vs.17.13 ng/ml &plusmn; 4.25; p=0.000), kao i kod bolesnika sa primarnom trombozom dubokih vena u poređenju sa zdravim ispitanicima (19.53 ng/ml &plusmn; 5.97 vs.17.13 ng/ml &plusmn; 4.25; p=0.023). &Scaron;to se genetskih analiza tiče, u okviru grupe bolesnika imali smo 25% homozigotnih i 58% heterozigotnih nosilaca mutacije gena za PAI-1, dok 17% bolesnika nije imalo pomenutu gensku mutaciju. U okviru kontrolne grupe pak, bilo je 30% homozigotnih i 56% heterozigotnih nosilaca mutacije a 14% ispitanika nije imalo mutaciju. Nije uočena značajna razlika u zastupljenosti 4G/4G genotipa između bolesnika sa različitim lokalizacijama venskog trombotskog procesa (distalna DVT 29% vs. proksimalna DVT 21% vs. DVT retke lokalizacije 12%; p=0.501), kao ni u zastupljenosti ovoga genotipa kod provocirane i spontane tromboze dubokih vena (27% vs. 23%; p=0.642), niti kod izolovane tromboze dubokih vena u poređenju sa plućnom tromboembolijom (25% vs. 33%; p=0.735). Procena rizika za nastanak venske tromboze u odnosu na postojanje poremećaja globalne funkcionalnosti fibrinoliznog mehanizma, u odnosu na patolo&scaron;ke koncentracije pojedinih komponenti fibrinoliznog mehanizma, kao i u odnosu na postojanje 4G/4G mutacije u genu za PAI-1, pokazala je da suprimirana funkcionalnost fibrinoliznog mehanizma trostruko povećava rizik za nastanak tromboze dubokih vena (OR 3.02; CI 1.26-7.22), povi&scaron;en nivo PAI-1 nema uticaja na rizik od nastanka tromboze dubokih vena, na &scaron;ta ukazuje OR od 0.86 sa CI 0.59-1.25, povi&scaron;en nivo t-PA antigena ne utiče na rizik od nastanka tromboze dubokih vena (OR 1.53; CI 0.79-2.94), ali povi&scaron;ena koncentracija TAFI vi&scaron;e od dvostruko povećava ovaj rizik (OR 2.25; CI 1.16-4.35). Prema na&scaron;im rezultatima PAI-1 4G/4G genotip nema uticaja na rizik od nastanaka venske tromboze, &scaron;to potvrđuje OR koji iznosi 0.57 (0.27-1.20). Na osnovu dobijenih rezultata zaključujemo da bolesnici sa trombozom dubokih vena imaju suprimiranu funkcionalnost fibrinoliznog mehanizma u poređenju sa zdravim osobama, da je nivo t-PA antigena, kao i plazminogena značajno vi&scaron;i kod bolesnika sa provociranom venskom trombozom nego kod zdravih osoba, da nema razlike u koncentraciji PAI-1 između bolesnika sa venskom trombozom i zdravih osoba, ali da bolesnici sa trombozom dubokih vena, bez obzira na njenu lokalizaciju ili vrstu imaju značajno vi&scaron;e nivoe TAFI u poređenju sa zdravim ispitanicima. Pored toga možemo zaključiti da ne postoji razlika u zastupljenosti 4G/5G polimorfizma između bolesnika sa venskom trombozom i zdravih ispitanika. Konačno, možemo reći da na osnovu na&scaron;ih rezultata možemo zaključiti da suprimirana funkcionalnost fibrinoliznog mehanizma trostruko povećava rizik od nastanka tromboze dubokih vena, a povi&scaron;en nivo TAFI-a dvostruko povećava ovaj rizik, dok 4G/5G PAI-1 polimorfizam nema uticaja na rizik za nastanak venskog tromboembolizma.</p> / <p>Thrombosis is nowadays leading cause of morbidity and mortality worldwide. Lately, studies dealing with venous thromboembolism are very actual, since incidence of this disease is 2/1000 persons per year and its development is consequence of joint action of many different inherited and acquired risk factors. Precise recognition and understanding as many of those factors as possible represents imperative in fight against the first episode of venous thrombosis, and also against the recurrence of the disease. Numerous risk factors have been already recognized as constituent links of pathophysiological chain of venous thrombotic process, but it is also clear that the discovery of many of them are yet to come. Investigations of the role of fibrinolytic mechanism disorders in venous thrombosis are topical in the field. Although, we have some evidences that suppressed fibrinolytic activity increases the risk of this disease, still there are many open issues, especially those dealing with the role of individual factors of fibrinolytic mechanism in venous thrombosis, and with the role of global fibrinolytic function in different types and localizations of venous thrombotic disease. Further, investigation of the effects of gene mutations on individual fibrinolytic mechanism components, its global functionality and indirectly to the risk of venous thrombosis, also attracts the attention of experts, given the inconsistency of results obtained from studies dealing with this issue. The aim of this study was to evaluate fibrinolytic mechanism global functionality, as well as functionality of its integral individual components in patients with different venous thrombosis types and localizations, and to compare them with those of the healthy persons. In addition, the aim was to evaluate presence of 4G/5G PAI-1 polymorphism in patients with venous thrombosis compared with healthy subjects. The case group consisted of 100 patients with deep vein thrombosis and the control group consisted of 100 healthy subjects who had never had thrombotic incident. Exclusion criteria were: documented haemostatic disease, taking drugs proven to affect fibrinolytic function, acute illness within 6 weeks before blood sampling, malignancy, pregnancy, severe mental illness, kidney or liver diseases, autoimmune diseases, examinee refusal to sign the informed consent. We used euglobulin cloth lysis time test as test for global fibrinolytic mechanism function estimation, and also determined: t-PA and TAFI concentrations using ELISA method and PAI-1 concentrations using chromogenic substrate method. The presence of PAI-1 4G/5G gene polymorphism was determined by genetic testing. According to results 56% of patients had unprovoked and 44% had provoked venous thrombosis. Proximal venous thrombosis was present in 63% of cases, distal venous thrombosis in 29% of cases and atypical venous thrombosis in 8% of them. Significantly higher frequency of hypertension was present in patients with primary deep vein thrombosis than in the group of patients with provoked deep vein thrombosis (61% vs. 16%, p = 0.000). Patients who have experienced deep vein thrombosis had a significantly longer clot lysis time, and suppressed fibrinolysis function compared with healthy controls (204.34 &plusmn; 51.24 vs. 185.62 &plusmn; 42.30, p = 0.011). Also, this parameter was significantly longer in patients with isolated distal deep vein thrombosis compared with healthy controls (218.32&plusmn;41.12 vs. 185.62&plusmn;42.30: p=0.001), such as in patients with provoked venous thrombosis compared with controls (208.18&plusmn;48.53 vs. 185.62&plusmn;42.30; p=0.018). Patients with venous thrombosis had significantly higher TAFI concentrations in comparison with healthy volunteers (19.70 ng/ml &plusmn; 5.17 vs. 17.13 ng/ml &plusmn; 4.25; p=0.001). Patients with provoked venous thrombosis had significantly higher concentrations of plasminogen (127.14 % &plusmn; 27.73 vs. 117.09 % &plusmn; 24.49; p= 0.044) and t-PA (20.02 ng/ml &plusmn; 11.07 vs. 16.78 ng/ml &plusmn; 8.08; p=0.042), in comparison with controls. Regarding TAFI, we noticed that patients with isolated distal deep vein thrombosis have higher values of this parameter compered with healthy people (20.72 ng/ml &plusmn; 4.96 vs. 17.13 ng/ml &plusmn; 4.25; p=0.001), such as patients with proximal deep vein thrombosis (19.37 ng/ml &plusmn; 5.33 vs. 17.13 ng/ml &plusmn; 4.25; p=0.013). The same was obtained when compared patients with provoked venous thrombosis and controls (19.93 ng/ml &plusmn; 3.97 vs. 17.13 ng/ml &plusmn; 4.25; p=0.000), and patients with unprovoked venous thrombosis and controls (19.53 ng/ml &plusmn; 5.97 vs. 17.13 ng/ml &plusmn; 4.25; p=0.023). As far as genetic analysis, in the group of patients we had 25% homozygous and 58% heterozygous carriers of PAI-1 gene mutation, whereas 17% of patients did&#39;t have this mutation. In controls, we had 30% homozygous and 56% heterozygous carriers of mutation and 14% of those without mutation. There was no significant difference in the frequency of 4G/4G genotype between patients with different localization of venous thrombotic process (distal DVT 29% vs. proximal DVT 21% vs. rare localization DVT 12%, p = 0.501), as well as the representation of this genotype in provoked and unprovoked deep vein thrombosis (27% vs. 23%, p = 0.642), or in isolated deep vein thrombosis compared to pulmonary thromboembolism (25% vs. 33%, p = 0.735). Finaly, our results show that suppressed fibrinolytic functionality threefold increases risk of venous thrombosis (OR 3.02, CI 1.26-7.22), elevated levels of PAI-1 have no effect on the risk of deep vein thrombosis, as evidenced by OR of 0.86 with CI 0.59-1.25, elevated levels of t-PA antigen do not affect the risk of deep venous thrombosis (OR 1.53; CI 0.79-2.94), but increased concentration of TAFI increases more than twice this risk (OR 2.25; CI 1.16-4.35). PAI-1 4G/4G genotype does not affect venous thrombotic risk (OR 0.57; CI 0.27-1.20). Based on these results, we conclude that patients with deep vein thrombosis have suppressed fibrinolytic mechanism functionality compared to healthy subjects, the levels of t-PA antigen and plasminogen are significantly higher in patients with provoked venous thrombosis than in healthy subjects, there is no difference in PAI-1 concentration in patients with venous thrombosis and healthy persons, but the patients with deep vein thrombosis, regardless of its localisation or the type have a significantly higher level of TAFI as compared with healthy subjects. In addition, we can conclude that there is no difference in the prevalence of 4G/5G polymorphism in patients with venous thrombosis and healthy persons. Finally, we can say that suppressed fibrinolytic mechanism functionality threefold increases risk of deep vein thrombosis, elevated level of TAFI-a double increases this risk, while PAI-1 4G/5G polymorphism has no influence on the risk of venous thromboembolism.</p>

Hemocoagulation, blood coagulation, is an important indicator of hemostatic balance in the human body. There are many ways how to investigate blood clotting. In practice, next to the tests investigating time of coagulation cascade from view of internal way (APTT – activated partial tromboplastin time) and external way (PT – prothrombin time) is often used determining of fibrinogen concentration by Clauss method. Derived fibrinogen method determined fibrinogen concentration, too, by subtracting form the clotting curve in PT test. The reaction for Clauss method is not necessary here. Derived fibrinogen is not used much in practice. This is the reason, why the thesis related to this project will try to find relationship between concentration of fibrinogen and standard tests APTT and PT. Clinical data will be used for this.

L’activité plaquettaire joue un rôle clé dans la physiopathologie de l’infarctus du myocarde avec sus-décalage du segment ST (IDM ST+). La réactivité plaquettaire est augmentée lors d’un IDM ST+, traité par angioplastie primaire ou par fibrinolyse avec succès. La relation entre la réactivité plaquettaire résiduelle après un pré-traitement, la charge athérothrombotique et la qualité de la reperfusion myocardique reste peu décrite dans le cadre des IDM ST+. La tomographie par cohérence optique et celle plus récente par domaine de fréquence offrent une imagerie de haute résolution permettant l’identification et la quantification précise de la charge athérothrombotique intracoronaire (CAT). La CAT résiduelle intra-stent peut aider à mieux comprendre la relation entre la réactivité plaquettaire et la reperfusion. Dans un premier temps, nous avons évalué la précision des tests VerifyNow et PFA en comparaison à l’agrégométrie optique pour la détection de l’hyperréactivité plaquettaire dans le contexte particulier des IDM ST+ traités par fibrinolyse avec succès. Nous avons aussi décrit les caractéristiques de la CAT avant et après angioplastie selon la présence d’une rupture de plaque ou d’une érosion coronaire chez des patients traités par fibrinolyse avec succès. Ensuite, nous avons étudié la relation entre la réactivité plaquettaire résiduelle (en réponse au ticagrelor et à l’aspirine) mesurée par VerifyNow et la reperfusion myocardique chez des patients traités par angioplastie primaire. En parallèle, nous avons décrit la relation entre la reperfusion myocardique et la CAT résiduelle intra-stent dans la même cohorte. / Platelet activity plays a key role in the pathophysiology of ST-segment elevation myocardial infarction (STEMI). Platelet reactivity is enhanced after STEMI treated with primary percutaneous coronary intervention (PCI) or successful thrombolysis. The relationship between residual platelet reactivity after pre-treatment, the atherothrombotic burden and the quality of reperfusion remains poorly described in STEMI. Optical coherence tomography (OCT) and optical frequency domain imaging (OFDI) provide high resolution imaging allowing identification and accurate quantification of intracoronary atherothrombotic burden (ATB). Residual in-stent ATB may help to better understand the relation between platelet reactivity and reperfusion. First, we assessed the accuracy of the point-of-care tests VerifyNow and PFA in comparison to light transmittance aggregometry to detect high on-treatment platelet reactivity (HPR) in the particular setting of STEMI successfully treated with fibrinolysis. We also described the characteristics of ATB before and after PCI according to the underlying presence of rupture or erosion in patients successfully treated with fibrinolysis. Then, we assessed the relationship between residual platelet reactivity (in response to ticagrelor and aspirin) using VerifyNow and myocardial reperfusion in primary PCI patients. In parallel, we studied the relationship between myocardial reperfusion and residual in-stent ATB in the same cohort.

<p> Inherited bleeding disorders can be caused by mutations affecting platelet, coagulation, or fibrinolytic proteins. Quebec platelet disorder (QPD) is a rare, autosomal dominant disorder associated with increased expression of the fibrinolytic enzyme urokinase plasminogen activator (uPA) in platelets. Individuals with QPD experience delayed-onset bleeding after hemostatic challenges that is attenuated with fibrinolytic inhibitor therapy. The aims of this thesis were to: 1) determine if increased platelet uPA contributes to QPD clot lysis in vitro; 2) investigate whether QPD individuals have increased urinary uPA, as some individuals experience hematuria; and 3) map the genetic locus of QPD, and look for the putative mutation. Studies of clot lysis indicated that QPD platelets induce a gain-of-function defect in fibrinolysis when platelets are incorporated into clots. This suggests that accelerated fibrinolysis may contribute to QPD bleeding. Studies of urinary uPA in QPD showed that uPA is not increased, indicating that hematuria in QPD is likely a consequence of increased platelet uPA. This finding also suggests that uPA overexpression in QPD may be megakaryocyte-specific. Linkage studies showed that QPD is strongly linked to a 2 megabase region on chromosome 10 that harbors the uPA gene, PLA U. No mutations in PLA U or its regulatory regions were identified; however, a common haplotype for a 32.5 kilobase region around PLA U, including inheritance of a rare, linked polymorphism, suggests this is the most likely locus for QPD. mRNA studies in QPD platelets showed that QPD selectively increases expression of the linked PLAU allele, without similar increases in megakaryocyte progenitors or in saliva. These findings implicate a cis-mutation near PLA U as the cause of QPD. This thesis provides novel insights on the fibrinolytic abnormality in QPD blood, and on the QPD genetic locus. which will be important for identifying the precise mutation that converts normally prohemostatic platelets to profibrinolytic cells. </p> / Thesis / Doctor of Philosophy (PhD)

Background: SARS-CoV-2 infections are suspected to trigger the coagulation system through various pathways leading to a high incidence of thromboembolic complications, hypercoagulation and impaired fibrinolytic capacity were previously identified as potentially mechanisms. A reliable diagnostic tool for detecting both is still under discussion. This retrospective study is aimed to examine the prognostic relevance of early viscoelastic testing compared to conventional laboratory tests in COVID-19 patients with acute respiratory distress syndrome (ARDS). - Methods: All mechanically ventilated patients with COVID-19 related ARDS treated in our intensive care unit (ICU) between January and March 2021 were included in this study. Viscoelastic testing (VET) was performed using the ClotPro® system after admission to our ICU. Prevalence of thromboembolic events was observed by standardized screening for venous and pulmonary thromboembolism using complete compression ultrasound and thoracic computed tomography pulmonary angiography at ICU admission, respectively. We examined associations between the severity of ARDS at admission to our ICU, in-hospital mortality and the incidence of thromboembolic events comparing conventional laboratory analysis and VET. ECMO related coagulopathy was investigated in a subgroup analysis. The data were analyzed using the Mann–Whitney U test. - Results: Of 55 patients enrolled in this study, 22 patients required treatment with ECMO. Thromboembolic complications occurred in 51% of all patients. Overall hospital mortality was 55%. In patients with thromboembolic complications, signs of reduced fibrinolytic capacity could be detected in the TPA assay with prolonged lysis time, median 460 s (IQR 350–560) vs 359 s (IQR 287–521, p = 0.073). Patients with moderate to severe ARDS at admission to our ICU showed increased maximum clot firmness as a sign of hypercoagulation in the EX-test (70 vs 67 mm, p < 0.05), FIB-test (35 vs 24 mm, p < 0.05) and TPA-test (52 vs 36 mm, p < 0.05) as well as higher values of inflammatory markers (CRP, PCT and IL6). ECMO patients suffered more frequently from bleeding complications (32% vs 15%). - Conclusion: Although, the predictive value for thromboembolic complications or mortality seems limited, point-ofcare viscoelastic coagulation testing might be useful in detecting hypercoagulable states and impaired fibrinolysis in critically ill COVID-19 ARDS patients and could be helpful in identifying patients with a potentially very severe course of the disease.

Diss. (sammanfattning) Umeå : Umeå universitet, 2009. / Härtill 4 uppsatser. Även tryckt utgåva.