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The adipokine leptin is expressed at higher concentrations in obese subjects, who also incidentally have a higher prevalence of hypertension. The pathogenesis of this obesity-related hypertension is controversial and is believed to be related to many factors including increased sympathetic activity, abnormalities of the renin-angiotensin system, sodium retention, and an endotheliopathy acting independently or in concert with increased circulating leptin. This review discusses the potential mechanisms through which changes in leptin signal transduction pathways in tissues with the leptin receptor, especially the hypothalamus, mediate the pathogenetic relationships between obesity and hypertension. The hypothesis is explored that leptin effects on blood pressure (BP) are meditated by the downstream effects of hypothalamic leptin signaling and ultimately result in activation of specific melanocortin receptors located on sympathetic neurons in the spinal cord. The physiological consequences of this sympathetic activation of the heart and kidney are activation of the renin-angiotensin system, sodium retention and circulatory expansion and finally, elevated BP. This sequence of events has been elegantly demonstrated with leptin infusion and gene knockout studies in animal models but has not been convincingly reproducibly confirmed in humans. Further studies in human subjects on the specific roles of hypothalamic leptin in essential hypertension are indicated as elucidation of the signaling pathways should provide better understanding of the role of weight loss in BP control and afford an additional mechanism for pharmacologic control of BP in adults and children at risk of cardiovascular disease.

The metabolic syndrome is a combination of metabolic and clinical features that aggregate in individuals and increase cardiovascular disease (CVD) risk considerably. It is believed, although sometimes controversially, that the underlying basis for this syndrome is insulin resistance (IR) and accompanying compensatory hyperinsulinemia. Insulin and insulin-like growth factors (IGFs) have significant homology and interact with differing affinity with the same receptors. Therefore, their actions can be complementary, and this becomes particularly significant clinico-pathologically when their circulating levels are altered. This review of currently available information attempts to answer the following questions: (1) Is there any evidence for changes in the components of the IGF system in individuals with established CVD or with increased CVD risk as with the metabolic syndrome? (2) What are the underlying mechanisms for interactions, if any, between insulin and the IGF system, in the genesis of CVD? (3) Can knowledge of the pathophysiological changes in the IGF system observed in macrosomic newborn infants and growth hormone (GH)-treated children and adults explain some of the observations in relation to the IGF system and the metabolic syndrome? (4) Can the experimental and clinical evidence adduced from the foregoing be useful in designing novel therapies for the prevention, treatment, and assignment of prognosis in metabolic syndrome-associated disease, particularly ischemic heart disease? To answer these questions, we have performed a literature review using bibliographies from PubMed, Medline, and Google Scholar published within the last 10 years. We suggest that IGF-1 levels are reduced consistently in individuals with the metabolic syndrome and its components and in those with ischemic CVD. Such changes are also seen with GH deficiency in which these changes are partially reversible with GH treatment. Furthermore, changes are seen in levels and interactions of IGF-binding proteins in these disorders, and some of these changes appear to be independent of IGF-binding capability and could potentially impact on risk for the metabolic syndrome and CVD. The promising therapeutic implications of these observations are also discussed.

The concept of metabolic syndrome in psychiatry provides a united front for confronting a series of metabolic changes that are predictive of cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM), which are highly prevalent in severe mental disorders (SMDs), such as schizophrenia, bipolar disorders, and severe depression. This review attempts to answer the following questions: (1) Is there evidence of significantly increased risk of metabolic syndrome in SMDs? (2) How is this evidence explained by stress theory and functional polymorphism? (3) What role can psychopharmacology and psychosocial therapies play in minimizing the problem? We have done a historical review using related literature from Medline. Compared with the general population, metabolic syndrome is two to three times more common in SMDs. The evidence for this predates the era of antipsychotic drugs. Altered glucose metabolism and dyslipidemia seem to be integral to SMDs. However, major psychotropic drugs are associated with metabolic syndrome, because of their activity at the appetite-stimulating receptors. SMDs seem to trigger a pathogenic cycle that fuels metabolic syndrome. To explain these findings, a neural diathesis-stress model has been proposed. Furthermore, candidate genes associated with receptors for weight gain are implicated. Using metformin (≥750 mg/day) may significantly reduce metabolic risks, and the data support consideration of this intervention for psychiatric patients taking antipsychotics. The obstacles to the implementation of the available guidelines for monitoring metabolic effects and changing unhelpful lifestyles need to be overcome by making monitoring mandatory and integration of physical exercise into routine care. Drug development and genotyping for the risk factors are future solutions.

Introduction: The plasma B-type natriuretic peptide (BNP) level is elevated in cardiac ischemia and may be useful in assessing prognosis in acute coronary syndromes (ACS). This study aimed to: (1) establish BNP levels and its determinants in a healthy Gulf Arab population and in a group of patients with acute myocardial infarction and (2) investigate associations between BNP levels and markers of myocardial damage (ejection fractions, cardiac troponin I [cTnI] levels) and inflammation (serum C-reactive protein [CRP])., Subjects and Methods: We studied 2 groups of Arab subjects: (1) Healthy control (HC), 142 healthy control subjects; (2) Coronary heart disease (CHD), 257 patients with proven acute myocardial infarction within 1 day of admission. Each subject was assessed clinically, and ejection fractions (left ventricular ejection fraction [LVEF]) were determined by echocardiography in those with CHD. Fasting blood samples were processed for full blood counts and serum glucose, urea, creatinine, uric acid, and lipids (total cholesterol [TC], triglycerides [TG], high-density lipoprotein cholesterol [HDL-C], low-density lipoprotein [LDL], and apolipoprotein B [apoB]), cTnI, BNP, and high-sensitivity (hs) CRP levels. The results were compared between groups, and the associations of BNP with other parameters were explored., Results: In comparison to HC, the CHD group had a greater waist-hip ratio (WHR) (P < 0.01), worse atherogenic profile, worse renal function, and higher values for CRP and BNP (all P < 0.001). There were no significant differences in values for BNP related to age, diabetes, hypertension, WHR, and hematocrit, although there was a consistent trend in both HC and CHD groups toward a negative relationship of BNP with body mass, TG, and apoB levels, and a positive relationship with HDL, independent only for HDL and apoB on multiple logistic regression. No correlations could be established with cTnI, CRP, and LVEF. The patterns of cross-correlations did not differ significantly with diabetic status., Conclusion: In an Arab population with CHD, blood levels of BNP are higher than in a healthy control population and appear correlated to body mass and atherogenic lipids but not CRP, troponin, or ejection fraction. BNP levels did not appear to be influenced by the classical CHD risk factors of diabetes, hypertension, cigarette smoking, hematocrit, or WHR. The independent link with atherogenic dyslipidemia suggests that BNP is important in atherogenesis and may not be just an index of cardiac contractile dysfunction.