local (7, 8). Uma explicacao razoavel para a reduzida incidencia da aterosclerose e a regulacao autonoma alterada nos individuos com SD, com efeitos de pequenas mudancas na sensibilidade baroreflexa e na resposta de excitacao simpatica (9, 10, 11). A reduzida resposta do simpatico ao estresse e suportada pelos baixos niveis circulantes de catecolaminas em resposta ao exercicio incrementado na bicicleta ergometrica em individuos com SD (12).Na teoria da acidez na aterosclerose a predominancia do simpatico e o primeiro passo e a tensao tangencial hemodinamica o ultimo passo na cascata de eventos levando ao processo aterogenico (13, 14)*Nota:A resistencia a insulina pode contribuir para uma aumentada atividade do sistema nervoso simpatico (15) e a atividade do SNS pode similarmente aumentar a resistencia a insulina (16)1.Yla-Herttuala S, Luoma J, Nikkari T, Kivimaki T. Down's syndrome and atherosclerosis. Atherosclerosis. 1989 Apr;76(2-3):269-72.2.Murdoch JC, Rodger JC, Rao SS, Fletcher CD, Dunnigan MG. Down's syndrome: an atheroma-free model? Br Med J. 1977 Jul 23;2(6081):226-8.3.Moss TJ, Austin GE. Pre-atherosclerotic lesions in Down syndrome. J Ment Defic Res. 1980 Jun;24(2):137-41.4.Chaney RH. Neurogenic atherosclerosis in mentally retarded persons. J Ment Defic Res. 1987 Sep;31 ( Pt 3):235-405.Draheim CC, McCubbin JA, Williams DP. Differences in cardiovascular disease risk between nondiabetic adults with mental retardation with and without Down syndrome. Am J Ment Retard. 2002 May;107(3):201-116.Draheim CC, Geijer JR, Dengel DR. Comparison of intima-media thickness of the carotid artery and cardiovascular disease risk factors in adults with versus without the Down syndrome. Am J Cardiol. 2010 Nov 15;106(10):1512-67.Gnasso A, et al. Association Between Intima-Media Thickness and Wall Shear Stress in Common Carotid Arteries in Healthy Male Subjects. Circulation. 1996;94:3257-32628.Bots M. L, et al. Increased Common Carotid Intima-Media Thickness. Adaptive Response or a Reflection of Atherosclerosis? Findings From the Rotterdam Study. Stroke. 1997;282442 .9.Agiovlasitis S, Collier SR, et al. Autonomic response to upright tilt in people with and without Down syndrome. Res Dev Disabil. 2010 May-Jun;31(3):857-63.10.Iellamo F, Galante A, et al. Altered autonomic cardiac regulation in individuals with Down syndrome. Am J Physiol Heart Circ Physiol. 2005 Dec;289(6):H2387-91.11.Bo Fernhall and Mari Otterstetter. Attenuated responses to sympathoexcitation in individuals with Down syndrome. J Appl Physiol 94: 21582165, 2003.12.Eberhard Y, Etarradossi J and Terminarias A. Biochemical changes and catecholamine response in Downs syndrome adolescents in relation to incremental maximal exercise. J Ment Defic Res 35: 140-146, 199113. Predominancia do sistema nervoso simpatico: o fator primario na cascata de eventos levando a espiral aterogenica. , Carlos Monteiro, 22 de Fevereiro de 2010 em http://teoriadaacidez.blogspot.com/2010/02/predominancia-do-sistema-nervoso.html 14.Carlos ETB Monteiro, Ambiente acido evocado por estresse cronico: Um novo mecanismo para explicar aterogenese., disponivel no Infarct Combat Project, Janeiro 28, 2008 em http://www.infarctcombat.org/AcidityTheory-p.pdf (versao em portugues) 15.Pikkujamsa SM, Huikuri HV, Airaksinen KE, Rantala AO, Kauma H, Lilja M, Savolainen MJ, Kesaniemi YA. Heart rate variability and baroreflex sensitivity in hypertensive subjects with and without metabolic features of insulin resistance syndrome. Am J Hypertens 1998;11:5233116.Moan A, Nordby G, Rostrup M, Eide I, Kjeldsen SE. Insulin sensitivity, sympathetic activity, and cardiovascular reactivity in young men. Am J Hypertens 1995;8:26875