The prevalence of the metabolic syndrome has increased worldwide over the past few years. (CKD) [1]. The National Cholesterol Education Program’s Adult Treatment Panel III statement (ATP III) recognized six components of the MetS that relate to CVD: abdominal obesity, atherogenic dyslipidemia, raised blood pressure (BP), insulin resistance (I.R.)/glucose intolerance, and proinflammatory and prothrombotic state [2]. A major problem concerning the WHO and NCEP ATPIII definitions was their applicability to different ethnic groups, especially when obesity cutoffs were to be defined. This is particularly obvious for the risk of type II DM, which may be associated with much lower levels of obesity in Asians compared to Caucasians. The International Diabetes Federation has then proposed a new set of criteria with ethnic/racial specific cutoffs [3]. The MetS central feature is usually obesity, and the MetS is usually a growing epidemic in the United States and throughout the world [4, 5]. Approximately 1 adult in 4 or 5 5, depending on LY335979 the country, has the MetS. Incidence increases with age; it has been estimated that in people over 50 years of age, the MetS affects more than 40% of the population in the United States and nearly 30% in Europe [6, 7]. Whether the effects of the LY335979 MetS are due to a sum of comorbidities or to individual features is still a matter of argument; however, there is sufficient data to support an increased risk of CVD in people affected by the LY335979 MetS in the absence of other baseline risk factors [8C10]. Central obesity is an impartial risk factor for CVD and is associated with MetS [11]. Central obesity predisposes to diabetic nephropathy, hypertensive nephrosclerosis, and focal segmental glomerulosclerosis and represents an independent risk factor for the development and progression of CKD [12]. Obesity and the development of I.R. are thought to be a central feature, contributing to the significant morbidity and mortality associated with the MetS and development of a particular resistant form of HT [13C15]. LY335979 The development of resistant HT in individuals with MetS can be attributed to a number of factors including proinflammatory cytokines, improper LY335979 activation of the renin-angiotensin system (RAAS), vasoconstriction from increased sympathetic nervous system (SNS) activation, and dysregulation in adipokines production and secretion [16]. Several components of the MetS are associated with indirect or direct markers of adrenergic overdrive [17]. This review will focus on current understanding of the mechanisms through which sympathetic overactivity may be interlaced to the metabolic syndrome, with particular regard to the role of insulin resistance and of some adipokines. 2. Pathophysiology of the Mets In 1988, Reaven first postulated the syndrome X, which is now named Metabolic Syndrome (MetS) [14]. Reaven noticed the frequent association of factors leading to the development of CVD: glucose intolerance, hyperinsulinemia, high serum triglycerides, low serum high-density lipoprotein cholesterol, and HT. I.R. was proposed as the driving force of the syndrome [14, 18]. Subsequently, other abnormalities, in particular prothrombotic and chronic proinflammatory says, were added to the definition of the MetS. Later on, abdominal obesity became the core of the syndrome [19C21]. Since metabolic abnormalities linked to I.R. are usually found in patients with abdominal obesity [22, 23] I.R. is considered to be the core of the MetS and central obesity its most important clinical clue [24]. 3. Metabolic Syndrome and Sympathetic Overactivity As BP and thermogenesis are both under adrenergic control, an alteration Rabbit polyclonal to SP3. in the SNS could be part of the pathophysiology of the MetS. Also, alterations in the sympathetic control of heart rate (HR), cardiac output, peripheral vascular resistance, and renal sodium handling may promote, alone or in combination, the development and progression of HT [25, 26]. Actually, sympathetic overdrive occurs in MetS. Many components of the MetS are characterized by an increased adrenergic activity. Interestingly, sympathetic overdrive is usually detectable in obese patients prone to MetS before HT occurs. Also, when obesity and HT are both present in the same patient the degree of sympathetic activation is much greater than in people that have either condition individually [27]. People with central weight problems show improved sympathetic anxious activity (SNA) in comparison with people with subcutaneous type of weight problems [28]. Improved sympathetic outflow continues to be reported in obese nonhypertensive people with the dedication of circulating catecholamines, urinary norepinephrine (NE), muscle tissue sympathetic nerve activity (MSNA) recordings of postganglionic sympathetic nerve materials, and renal NE spillover.