RESUMEN
The restoration of blood flow to the ischemic myocardium inflicts ischemia/reperfusion (I/R) heart injury (IRI). The main contributors to IRI are increased oxidative stress and subsequent excessive production of ROS, increased expression of NOS and peroxinitate, activation of MMPs, and enhanced posttranslational modifications of contractile proteins, which make them more susceptible to proteolytic degradation. Since the pathophysiology of IRI is a complex issue, and thus, various therapeutic strategies are required to prevent or reduce IRI and microvascular dysfunction, in the current study we proposed an innovative multi-drug therapy using low concentrations of drugs applied intracoronary to reach microvessels in order to stabilize the pro- and antioxidant balance during a MI in an in vivo pig model. The ability of a mixture of doxycycline (1 µM), ML-7 (0.5 µM), and L-NAME (2 µM) to modulate the pro- and antioxidative balance was tested in the left ventricle tissue and blood samples. Data showed that infusion of a MIX reduced the total oxidative status (TOS), oxidative stress index (OSI), and malondialdehyde (MDA). It also increased the total antioxidant capacity, confirming its antioxidative properties. MIX administration also reduced the activity of MMP-2 and MMP-9, and then decreased the release of MLC1 and BNP-26 into plasma. This study demonstrated that intracoronary administration of low concentrations of doxycycline in combination with ML-7 and L-NAME is incredibly efficient in regulating pro- and antioxidant balance during MI.
RESUMEN
The reasons for unfavorable changes in platelet concentrate (PC) quality during storage are not fully understood yet. We aimed to evaluate whether leukocytes and matrix metalloproteinases (MMPs) lead to a decrease in the quality of PCs and examine whether MMP inhibition will slow down the platelets' aging. Nine PCs were divided into three parts: (1) leukocyte-depleted (F) PCs, (2) PCs with no additional procedures (NF), and (3) PCs with the addition of an MMP inhibitor-doxycycline (D). Each PC was stored for 144 h, and a sample for testing was separated from each part on the day of preparation and after 24, 48, 72 and 144 h of storage. Blood morphological analysis, platelet aggregation, and the expression of activation markers were evaluated. MMP-2 and MMP-9 concentration, activity, and gene expression were assessed. Platelet aggregation decreased, and platelet activation marker expression increased during the storage. D concentrates showed the lowest level of platelet activation. In turn, leukocyte-depleted PCs showed the highest level of platelet activation in general. MMP-9 platelet activity was higher in leukocyte-containing concentrates at the end of the storage period. We concluded that the filtration process leads to a higher platelet activation level. The presence of doxycycline in PCs reduces the expression of the activation markers as compared to leukocyte-depleted concentrates.
Asunto(s)
Doxiciclina , Metaloproteinasa 9 de la Matriz , Metaloproteinasa 9 de la Matriz/metabolismo , Plaquetas/metabolismo , Activación Plaquetaria , LeucocitosRESUMEN
BACKGROUND: Platelets play a fundamental role in myocardial infarction and the pathogenesis of ischemia/reoxygenation (I/R) injuries. They contain matrix metalloproteinases (MMPs) that are involved in arterial thrombosis. The MMP inhibitor doxycycline has been shown to exert protective effects in I/R injuries involving various organs and mechanisms. OBJECTIVES: To explore the influence of doxycycline on platelet activation and MMP-2 activity during I/R. MATERIAL AND METHODS: Platelets isolated from the blood of healthy human volunteers were subjected to chemical I/R conditions. The study included aerobic controls (AERO), I/R platelets and I/R platelets pretreated with doxycycline (I/R+D). The concentration of doxycycline used was standardized to 10 µM. The analysis of platelet activation markers and platelet microvesicles (PMVs) was performed using flow cytometry. Adenosine diphosphate (ADP)-induced and collagen-induced aggregation, as well as MMP-2 activity and its concentration in platelets were evaluated. RESULTS: Doxycycline decreased the expression of activated glycoprotein IIb/IIIa on platelets (p = 0.043). Additionally, an increased expression of CD63 was observed in buffers containing PMVs after doxycycline administration (p = 0.043). The ADP-dependent aggregation of I/R platelets was significantly lower in comparison to AERO (p = 0.022). Furthermore, there was a stronger tendency of enhanced ADP-dependent aggregation in I/R platelets pretreated with doxycycline compared to platelets that underwent I/R without doxycycline. Higher MMP-2 activity was observed in I/R+D platelets compared to I/R platelets (p < 0.01). CONCLUSIONS: The inhibition of platelet MMP-2 by doxycycline attenuated platelet activation and protected platelets by preserving their aggregation ability.
Asunto(s)
Metaloproteinasa 2 de la Matriz , Activación Plaquetaria , Humanos , Adenosina Difosfato/metabolismo , Adenosina Difosfato/farmacología , Plaquetas , Doxiciclina/metabolismo , Doxiciclina/farmacología , Isquemia/tratamiento farmacológico , Isquemia/metabolismo , Metaloproteinasa 2 de la Matriz/efectos de los fármacos , Metaloproteinasa 2 de la Matriz/metabolismo , Activación Plaquetaria/efectos de los fármacos , Agregación Plaquetaria , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/metabolismo , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/farmacología , Inhibidores de la Metaloproteinasa de la Matriz/farmacologíaRESUMEN
Thrombotic occlusion of the coronary artery is a key component in the pathogenesis of myocardial ischemia and myocardial infarction (MI). The standard therapy for ischemia is revascularization and restoration of blood flow to previously ischemic myocardium. Paradoxically, reperfusion may result in further tissue damage called ischemia/reperfusion injury (IRI). Platelets play a major role in the pathogenesis of MI and IRI, since they contribute to the thrombus and microthrombi formation, inflammation, release of immunomodulatory mediators, and vasoconstrictive molecules. Antiplatelet therapies have proven efficacy in the prevention of thrombosis and play a protective role in cardiac IRI. Beyond the deterioration effect of platelets in MI and IRI, in the 90s the first reports on a protective effect of molecules released from platelets during MI appeared. However, the role of platelets in cardioprotection is still poorly understood. This review describes the involvement of platelets in MI, IRI, and inflammation. It mainly focuses on the protective role of platelets in MI and IRI. Platelets are involved in cardioprotection based on platelet-releasing molecules and antiplatelet therapy, apart from antiaggregatory effects. Additionally, the use of platelet-derived microparticles as possible markers of MI, with and without comorbidities, and their role in cardioprotection are discussed. This review is aimed at illustrating the present knowledge on the role of platelets in MI and IRI, especially in a context of cardioprotection.
RESUMEN
Atrial light chains (ALC1) are naturally present in adult heart atria, while ventricular light chains (VLC1) are predominant in ventricles. Degradation of VLC1 and reexpression of ALC1 in heart ventricles are associated with heart disorders in response to pressure overload. The aim of the current study was to investigate changes in myosin light chain expression after simulated ischemia and simulated reperfusion (sI/sR). Human cardiomyocytes (HCM) isolated from adult heart ventricles were subjected to chemical ischemia. The control group was maintained under aerobic conditions. Myocyte injury was determined by testing lactate dehydrogenase (LDH) activity. The gene expression of ALC1, VLC1 and MMP2 were assessed by reverse transcriptionquatitive PCR. Additionally, protein synthesis was measured using ELISA kits and MMP2 activity was measured by zymography. The results revealed that LDH activity was increased in sI/sR cellconditioned medium (P=0.02), confirming the ischemic damage of HCM. ALC1 gene expression and content in HCM were also increased in the sI/sR group (P=0.03 and P<0.001, respectively), while VLC1 gene expression after sI/sR was decreased (P=0.008). Furthermore, MMP2 gene expression and synthesis were lower in the sI/sR group when compared with the aerobic control group (P<0.001 and P=0.03, respectively). MMP2 activity was also increased in sI/sR cellconditioned medium (P=0.006). In conclusion, sI/sR treatment led to increased ALC1 and decreased VLC1 expression in ventricular cardiomyocytes, which may constitute an adaptive mechanism to altered conditions and contribute to the improvement of heart function.