Hemodialysis improves endothelial venous function in end-stage renal disease

The objective of the present study was to determine the acute effect of hemodialysis on endothelial venous function and oxidative stress. We studied 9 patients with end-stage renal disease (ESRD), 36.8 ± 3.0 years old, arterial pressure 133.8 ± 6.8/80.0 ± 5.0 mmHg, time on dialysis 55.0 ± 16.6 months, immediately before and after a hemodialysis session, and 10 healthy controls matched for age and gender. Endothelial function was assessed by the dorsal hand vein technique using graded local infusion of acetylcholine (endothelium-dependent venodilation, EDV) and sodium nitroprusside (endothelium-independent venodilation). Oxidative stress was evaluated by measuring protein oxidative damage (carbonyls) and antioxidant defense (total radical trapping antioxidant potential - TRAP) in blood samples. All patients were receiving recombinant human erythropoietin for at least 3 months and were not taking nitrates or a-receptor antagonists. EDV was significantly lower in ESRD patients before hemodialysis (65.6 ± 10.5) vs controls (109.6 ± 10.8; P = 0.010) and after hemodialysis (106.6 ± 15.7; P = 0.045). Endothelium-independent venodilation was similar in all comparisons performed. The hemodialysis session significantly decreased TRAP (402.0 ± 53.5 vs 157.1 ± 28.3 U Trolox/µL plasma; P = 0.001). There was no difference in protein damage comparing ESRD patients before and after hemodialysis. The magnitude of change in the EDV was correlated negatively with the magnitude of change in TRAP (r = -0.70; P = 0.037). These results suggest that a hemodialysis session improves endothelial venous function, in association with an antioxidant effect

Effects of different frequencies of transcutaneous electrical nerve stimulation on venous vascular reactivity

Transcutaneous electrical nerve stimulation (TENS) is a type of therapy used primarily for analgesia, but also presents changes in the cardiovascular system responses; its effects are dependent upon application parameters. Alterations to the cardiovascular system suggest that TENS may modify venous vascular response. The objective of this study was to evaluate the effects of TENS at different frequencies (10 and 100 Hz) on venous vascular reactivity in healthy subjects. Twenty-nine healthy male volunteers were randomized into three groups: placebo (n=10), low-frequency TENS (10 Hz, n=9) and high-frequency TENS (100 Hz, n=10). TENS was applied for 30 min in the nervous plexus trajectory from the superior member (from cervical to dorsal region of the fist) at low (10 Hz/200 &#956;s) and high frequency (100 Hz/200 &#956;s) with its intensity adjusted below the motor threshold and intensified every 5 min, intending to avoid accommodation. Venous vascular reactivity in response to phenylephrine, acetylcholine (endothelium-dependent) and sodium nitroprusside (endothelium-independent) was assessed by the dorsal hand vein technique. The phenylephrine effective dose to achieve 70% vasoconstriction was reduced 53% (P<0.01) using low-frequency TENS (10 Hz), while in high-frequency stimulation (100 Hz), a 47% increased dose was needed (P<0.01). The endothelium-dependent (acetylcholine) and independent (sodium nitroprusside) responses were not modified by TENS, which modifies venous responsiveness, and increases the low-frequency sensitivity of &#945;1-adrenergic receptors and shows high-frequency opposite effects. These changes represent an important vascular effect caused by TENS with implications for hemodynamics, inflammation and analgesia

Venous Endothelial Dysfunction In Chagas' Disease Patients Without Heart Failure [disfunção Endotelial Venosa Em Pacientes Com Doença De Chagas Sem Insuficiência Cardíaca]

OBJECTIVE: To analyze the venous endothelial function in Chagas' disease patients without heart failure. METHODS: The Chagas' disease Group (G1) was composed by 14 women and 2 men aged 46 ± 2,7 and the Control Group (G0) by 7 women and 1 man matched by age, weight and height. Dorsal Hand Vein Compliance Technique was used to evaluate the venous endothelial function. Crescent doses of phenylephrine were infused to get a 70% preconstriction of the vein; after that, acetylcholine and sodium nitroprusside were respectively administrated to analyze the endothelium-dependent and -independent venodilation. RESULTS: No significant systemic hemodynamic changes were observed in both groups during the experiment. The necessary phenylephrine dose to reach 70% preconstriction of the vein was significantly higher in the G1 (1116 ± 668,2 ng/ml) compared to G0 (103 ± 28 ng/ml) p = 0,05. The endothelium-dependent venous dilation was significantly lower in G1 (65,5 ± 8%) compared to G0 (137 ± 20 %) p = 0,009. No difference was observed in the endothelium-independent venous dilatation between groups. CONCLUSION: Patients with Chagas' disease without heart failure presented venous endothelial dysfunction.866466471Schmunis, G.A., American Trypanosomiasis as a public health problem (1994) Chagas' Disease and the Nervous System, pp. 3-29. , Pan American Health Organization (ed.). Washington, DC: Pan American OrganizationMarin-Neto, J.A., Simões, M.V., Sarabanda, A.V., Chagas'heart disease (1999) Arq Bras Cardiol, 72, pp. 247-280Mady, C., Barreto, A.C., Stolf, N., Lopes, E.A., Dauar, D., Wajngarten, M., Biopsia miocárdica na forma indeterminada da doença de Chagas (1981) Arq Bras Cardiol, 36, pp. 387-390Consolim-Colombo, F.M., Lopes, H.F., Rosetto, E.A., Endothelial function is preserved in Chagas' heart disease patients without heart failure (2004) Endothelium, 11 (5-6), pp. 241-246Guzman, Juan, C., Leon, Hernando, Casa, S., Juan, P., Disfunción autonómica y vascular en la fase asintomática de la enfermedad de Chagas (2004) Rev Colomb Cardiol, 11 (2), pp. 105-113Leiby, D.A., Rentas, F.J., Nelson, K.E., Evidence of Trypanosoma cruzi infection (Chagas' disease) among patients undergoing cardiac surgery (2000) Circulation, 102 (24), pp. 2978-2982Moncayo, A., Chagas disease: Current epidemiological trends after the interruption of vectorial and transfusional transmission in the Southern Cone countries (2003) Mem Inst Oswaldo Cruz, 5, pp. 577-591Ramos, S.G., Rossi, M.A., Microcirculation and Chagas' disease: Hypothesis and recent results (1999) Inst Med Trop São Paulo, 41 (2), pp. 123-129Soares Barreto-Filho, J.A., Consolim-Colombo, F.M., Ferreira Lopes, H., Martins Sobrinho, C.R., Guerra-Riccio, G.M., Krieger, E.M., Dysregulation of peripheral and central chemorefl ex responses in Chagas' heart disease patients without heart failure (2000) Circulation, 104 (15), pp. 1792-1798Rossi, M.A., Ramos, S.G., Coronary microvascular abnormalities in Chagas' disease (1996) Am Heart J, 132 (1), pp. 207-210Ianni, B.M., Arteaga, E., Frim, C.C., Pereira, C., Barreto, A.C., Mady, C., Chagas' heart disease: Evolutive evaluation of electrocardiographic and echocardiographic parameters in patients with the indeterminate form (2001) Arq Bras Cardiol, 77, pp. 59-62Consolim-Colombo, F.M., Filho, J.A., Lopes, H.F., Sobrinho, C.R., Otto, M.E., Riccio, G.M., Mady, 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Trypanosoma cruzi infection in rats (2002) Clin Sci, 103 (48 SUPPL.), pp. 64S-67S. , LondMorris, S.A., Tanowitz, H., Makman, M., Hatcher, V.B., Bilezikian, J.P., Trypanosoma cruzi: Alteration of cAMP metabolism following infection of human endothelial cell (1992) Exp Parasit, 74 (1), pp. 69-76Sunnemark, D., Frostegard, J., Orn, A., Harris, R.A., Cellular and cytokine characterization of vascular infl ammation in CBA/J mice chronically infected with Trypanosoma cruzi (1998) Scand J Immunol, 48 (5), pp. 480-484Tanowitz, H.B., Wittner, M., Morris, S.A., The putative mechanistic basis for the modulatory role of endothelin-1 in the altered vascular tone induced by Trypanosoma cruzi (1999) Endothelium, 6 (3), pp. 217-220Cardoni, R.L., Garcia, M.M., De Rissio, A.M., Proinfl ammatory and antiinflammatory cytokines in pregnant women chronically infected with Trypanosoma cruzi (2004) Acta Trop, 90 (1), pp. 65-72Ferreira, R.C., Ianni, B.M., Abel, L.C., Buck, P., Mady, C., Kalil, J., Cunha-Neto, 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Hemodialysis improves endothelial venous function in end-stage renal disease

The objective of the present study was to determine the acute effect of hemodialysis on endothelial venous function and oxidative stress. We studied 9 patients with end-stage renal disease (ESRD), 36.8 ± 3.0 years old, arterial pressure 133.8 ± 6.8/80.0 ± 5.0 mmHg, time on dialysis 55.0 ± 16.6 months, immediately before and after a hemodialysis session, and 10 healthy controls matched for age and gender. Endothelial function was assessed by the dorsal hand vein technique using graded local infusion of acetylcholine (endothelium-dependent venodilation, EDV) and sodium nitroprusside (endothelium-independent venodilation). Oxidative stress was evaluated by measuring protein oxidative damage (carbonyls) and antioxidant defense (total radical trapping antioxidant potential - TRAP) in blood samples. All patients were receiving recombinant human erythropoietin for at least 3 months and were not taking nitrates or α-receptor antagonists. EDV was significantly lower in ESRD patients before hemodialysis (65.6 ± 10.5) vs controls (109.6 ± 10.8; P = 0.010) and after hemodialysis (106.6 ± 15.7; P = 0.045). Endotheliumindependent venodilation was similar in all comparisons performed. The hemodialysis session significantly decreased TRAP(402.0 ± 53.5 vs 157.1 ± 28.3 U Trolox/μL plasma; P = 0.001). There was no difference in protein damage comparing ESRD patients before and after hemodialysis. The magnitude of change in the EDV was correlated negatively with the magnitude of change in TRAP (r = -0.70; P = 0.037). These results suggest that a hemodialysis session improves endothelial venous function, in association with an antioxidant effect