Percorrer por autor "Teixeira-Lemos, E."
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- Caracterização hemorreológica, bioquímica e cardiovascular num modelo de doença renal crónica moderada em ratoPublication . Garrido, P.; Costa, E.; Teixeira-Lemos, E.; Parada, B.; Teixeira, M.; Santos, P.; Piloto, N.; Sereno, J.; Alves, R.; Pinto, R.; Rocha-Pereira, P.; Figueiredo, A.; Nunes, S.; Romão, A. M.; Carvalho, L.; Couceiro, P.; Belo, L.; Santos-Silva, A.; Teixeira, F.; Reis, F.Chronic kidney disease (CKD) is a major public health problem throughout the world. The major outcomes include a rapid progression, with development of anaemia and serious complications, namely thromboembol ic and cardiovascular events. The pathophysiological alterations depend on the CKD degree, which will also determine the moment to initiate hemodialysis and recombinant erythropoietin (rhEPO) therapies Thus, the cardio-renal complication might be better prevented or delayed if CKD patients are earlier identified and treated for the associated anaemia, which will depend on a better characterization of moderate stages of CKD. This study aimed to characterization an animal of model of moderate CKD induced by partial (%) nephrectomy, by evaluating hemorheological, biochemical and cardiovascular profiles. Blood samples from control and CKD rats were collected at 0, 3, 9 and 15 weeks in order to evaluate: renal function, hemorheological parameters, iron metabolism, blood lipids, peripheral sympathetic and serotonergic systems, redox state and inflammatory markers. BP, tissues uophism indexes and kidney histomorphology were also assessed. Our data is consistent with a sustained moderate degree of CKD with a quickly compensated modest anaemia, though presenting iron metabolism disturbances. Despite the reasonable degree of functionality of the remnant kidney, as suggested by the anaemia correction and by the kidney hypertrophy, several important cardiovascular modifications were developed. Our model presented hypertension, dyslipidaemia, erythropoietic disturbances, sympathetic activation and oxidative stress. This model might be a good tool to study the cellular/molecularmechanisms underlying moderate stages of CKD and to evaluate the therapeutics efficacy for prevention, treatment/correction of cardiorenal anaemia syndromes and complications in early stages.
- Effect of recombinant human erythropoietin in a rat model of moderate chronic renal failure – focus on inflammation, oxidative Stress and function/renoprotectionPublication . Garrido, P.; Reis, F.; Costa, E.; Almeida, A.; Parada, B.; Teixeira-Lemos, E.; Santos, P.; Alves, R.; Sereno, J.; Pinto, R.; Tavares, C.A.; Figueiredo, A.; Rocha-Pereira, P.; Belo, L.; Santos-Silva, A.; Teixeira, F.Background/Aims: Chronic renal failure (CRF) patients develop anaemia, thus promoting cardiovascular complications, which seems to be favoured by the low kidney erythropoietin (EPO) production. The renal insufficiency degree might determine the moment to start recombinant human EPO (rhEPO) therapy. It has been attributed important non-hematopoietic effects to rhEPO, which might underlie cardio and renoprotection. This work aimed to evaluate the effect of rhEPO in a rat model of moderate CRF, focusing on inflammation, oxidative stress and function/renoprotection. Methods: Four groups (n=7) of male Wistar rats were evaluated during a 15 week follow-up period: control (without treatment); rhEPO (50 IU/Kg/wk Recormon®); CRF and CRF+rhEPO. Blood samples were collected at the beginning and 3, 9 and 12 weeks after 3/4 nephrectomy, in order to evaluate: renal function, haematological parameters, iron metabolism and serum proliferative (TGF-B1), inflammatory (TNF-a, CRP, IL-2 and IL-1B) and redox status (MDA, TAS and 3-NT) markers. Kidney gene expression of Il2, Vegf, Nos2 and Nos3 were assessed by real-time PCR. Blood pressure, heart rate and tissues trophy indexes were also estimated. Results: Our data are consistent with a sustained moderate degree of CRF with development of moderate and corrected anaemia and hypertension. The remnant kidney showed a proliferative profile, with increased mass (hypertrophism), upregulated tissue Vegf gene expression, accompanied by increased levels of serum TGF-B1. Serum 3-NT was augmented, suggesting oxidative stress, which was accompanied by a trend to higher kidney Nos gene expression of both isoforms. rhEPO treatment was able to partially attenuate renal function markers, totally correct anaemia, also demonstrating a proliferative and antioxidant action, suggesting renoprotection. Conclusion: This study suggests that rhEPO therapy might be recommended in moderate CRF stages in order to efficiently correct not only the anaemia but also the underlying deleterious mechanisms, due to a proliferative and antioxidant action on the remnant kidney.
- Erythropoietin doping as cause of sudden death in athletes: an experimental studyPublication . Piloto, N.; Teixeira, H.M.; Teixeira-Lemos, E.; Parada, B.; Garrido, P.; Sereno, J.; F. Pinto, A.F.; Costa, Elísio; Belo, L.; Santos-Silva, A.; Pinto, R.; Couceiro, P.; Neto, P.; Xavier, F.; Carvalho, L.; Teixeira, F.; Reis, F.Aims: To evaluate the cardiovascular (CV) effects of rhEPO treatment in rats under chronic aerobic exercise and to assess the probable cause of sudden death in one rat. Protocol: Male Wistar rats: control - sedentary; rhEPO - 50 IU/Kg/3xwk; swimming (EX) -1 hr, 3x/wk; EX+EPO. Hematology, catecholamines and serotonin, redox status and inflammation, were assessed. One rat of EX+EPO group suffered a sudden death episode. Results: rhEPO treatment in trained rats promoted several markers of increased CV risk. The sudden death rat tissues presented: lungs without signs of drowning; brain with vascular congestion; LV hypertrpphy and deregulations of cardiac fibers, together with a "cardiac liver", suggesting the hypothesis of heart failure as cause of death. Conclusion: The sudden death of a EX+EPO rat, due to a cardiac episode, together with the increased CV risk profile, strongly suggest a high life risk associated to the continuous rhEPO doping. The anatomo-pathological studies were determinant to establish the cause of death.
- Hemorheological and cardiovascular effects of erythropoietin in a rat model of sports dopingPublication . Piloto, N.; Teixeira, HM; Garrido, P.; Teixeira-Lemos, E.; Teixeira, M.; Parada, B.; Sereno, J.; Pinto, R .; Alves, R.; Santos, P.; Romão, AM; Nunes, S.; Neto, P.; Carvalho, L.; Couceiro, P.; Xavier, F.; Rocha-Pereira, P.; Costa, Elísio; Belo, L.; Santos-Silva, A.; Teixeira, F.; Reis, F.Recombinant human erythropoietin (rhEPO) has been therapeutically used for correction of anaemia. However, due to the increase in circulating red blood cells (RBCs) it promotes, thus increasing oxygen delivery to muscles and improving performance in sport, it has been also illegally used as sports doping. Besides the well known increase of hematocrit and blood viscosity; which might cause serious complications for the athletes, other disturbances could occur, whose mechanisms remain to be fully elucidated. This study aimed to evaluate the hemorheological and cardiovascular effects of administration of rhEPO to rats under chronic aerobic exercise. A ten week-protocol was performed in four male Wistar rat groups: control — sedentary; rhEPO — 50 IV/kg, 3 times/wk; exercised (EX) — swimming for 1 hr, 3 times/ wk; EX+rhEPO. rhEPO in trained rats promoted erythrocyte count increase, hypertension, heart hypertro-phy, sympathetic and serotonergic overactivation, as well as a trend to increased oxidative stress. In conclusion, rhEPO doping in rats under chronic exercise promotes not only the expected increased hematocrit, but also other serious deleterious cardiovascular and thromboembolic modifications, including live risk, which might be known and assumed by all sports authorities, including athletes and their physicians.