Adverse endothelial function and the insulin resistance syndrome

Urotensin II Receptor Modulation with 1,3,4-Benzotriazepin-2-one Tetrapeptide Mimics

Urotensin II receptor (UT) modulators that differentiate the effects of the endogenous cyclic peptide ligands urotensin II (UII) and urotensin II-related peptide (URP) offer potential for dissecting their respective biological roles in disease etiology. Selective modulators of hUII and URP activities were obtained using 1,3,4-benzotriazepin-2-one mimics of a purported bioactive γ-turn conformation about the Bip-Lys-Tyr tripeptide sequence of urocontrin ([Bip4]URP). Considering an active β-turn conformer about the shared Phe-Trp-Lys-Tyr sequence of UII and URP, 8-substituted 1,3,4-benzotriazepin-2-ones were designed to mimic the Phe-Bip-Lys-Tyr tetrapeptide sequence of urocontrin, synthesized, and examined for biological activity. Subtle 5- and 8-position modifications resulted in biased signaling and selective modulation of hUII- or URP-induced vasoconstriction. For example, p-hydroxyphenethyl analogs 17b-d were strong Gα13 and βarr1 activators devoid of Gαq-mediated signaling. Tertiary amides 15d and 17d negatively modulated hUII-induced vasoconstriction without affecting URP-mediated responses. Benzotriazepinone carboxamides proved to be exceptional tools for elucidating the pharmacological complexity of UT.

The Therapeutic Potential of Plant Polysaccharides in Metabolic Diseases

Plant polysaccharides (PPS) composed of more than 10 monosaccharides show high safety and various pharmacological activities, including immunoregulatory, antitumor, antioxidative, antiaging, and other effects. In recent years, emerging evidence has indicated that many PPS are beneficial for metabolic diseases, such as cardiovascular disease (CVD), diabetes, obesity, and neurological diseases, which are usually caused by the metabolic disorder of fat, sugar, and protein. In this review, we introduce the common characteristics and functional activity of many representative PPS, emphasize the common risks and molecular mechanism of metabolic diseases, and discuss the pharmacological activity and mechanism of action of representative PPS obtained from plants including Aloe vera, Angelica sinensis, pumpkin, Lycium barbarum, Ginseng, Schisandra chinensis, Dioscorea pposite, Poria cocos, and tea in metabolic diseases. Finally, this review will provide directions and a reference for future research and for the development of PPS into potential drugs for the treatment of metabolic diseases.

Oral L-Arginine (5 g/day) for 14 Days Improves Microcirculatory Function in Healthy Young Women and Healthy and Type 2 Diabetes Mellitus Elderly Women

OBJECTIVE

The aim of this study was to investigate the effect of oral supplementation with L-arginine on serum biochemical profile, blood pressure, microcirculation, and vasoreactivity/endothelial function in young controls, and elderly women with and without type 2 diabetes mellitus (T2DM).

METHODS

Healthy young (n = 25), healthy elderly (n = 25), and elderly women with type 2 diabetes mellitus (T2DME, n = 23, glycated Hb ≥6.4% and mean of 7.7 years for duration of the disease), aged 18-30 and older than 65 years, respectively, were included in the study. All patients underwent biochemical analysis (fasting glycemia and lipidogram), arterial blood pressure, nailfold videocapillaroscopy (capillary diameters, functional capillary density [FCD], peak red blood cell velocity [RBCVmax] after 1 min ischemia, time to reach peak RBCV [TRBCVmax]), and venous occlusion plethysmography (vasoreactivity), before and after 14 days of oral supplementation with L-arginine (5 g/day).

RESULTS

L-Arginine did not change fasting glycemia and lipidogram, but it decreased systolic, diastolic, and mean arterial pressure in elderly women, increased RBCVmax in all groups, and did not decrease TRBCVmax in T2DME. Capillary diameters and FCD remained unchanged in all groups. L-Arginine improved vasoreactivity during reactive hyperemia and after sublingual nitroglycerin (0.4 mg) in all groups.

CONCLUSION

L-Arginine supplementation (5g/day during 14 days) was able to improve vascular/microvascular health in the elderly women with or without T2DM.

Role of Vitamin B12 and Folate in Metabolic Syndrome

Metabolic syndrome (MS) is a collection of pathological metabolic conditions that includes insulin resistance, central or abdominal obesity, dyslipidemia, and hypertension. It affects large populations worldwide, and its prevalence is rising exponentially. There is no specific mechanism that leads to the development of MS. Proposed hypotheses range from visceral adiposity being a key factor to an increase in very-low-density lipoprotein and fatty acid synthesis as the primary cause of MS. Numerous pharmaceutical therapies are widely available in the market for the treatment of the individual components of MS. The relationship between MS and vitamin B complex supplementation, specifically folic acid and vitamin B12, has been a subject of investigation worldwide, with several trials reporting a positive impact with vitamin supplementation on MS.

In this study, an all-language literature search was conducted on Medline, Cochrane, Embase, and Google Scholar till September 2021. The following search strings and Medical Subject Headings (MeSH) terms were used: “Vitamin B12,” “Folate,” “Metabolic Syndrome,” and “Insulin Resistance.” We explored the literature on MS for its epidemiology, pathophysiology, newer treatment options, with a special focus on the effectiveness of supplementation with vitamins B9 and B12.

According to the literature, vitamin B12 and folate supplementation, along with a host of novel therapies, has a considerable positive impact on MS. These findings must be kept in mind while designing newer treatment protocols in the future.

Influence of Physical Activity on the Regulation of Disease of Elderly Persons with Metabolic Syndrome

Metabolic syndrome is a group of metabolic risk factors whose combination significantly contributes to the development of the risk of cardiovascular disease, diabetes, stroke, some cancers and is a clear indicator of morbidity rate. The aim of this study was to identify physical activity programs that can successfully influence the reduction of risk factors in metabolic syndrome of the elderly. Subjects were aged between 60 and 80 years, had three of five signs of metabolic syndrome, and were randomly divided into three groups of 20 subjects. The first group conducted a continuous cycling ergometer (55% VO₂max), the second group a physical activity strength program and the third was a control group. Before and after the experimental treatment body composition, biochemical parameters, functional parameters, cardiovascular functions, metabolic and hematological system were determined. Significant differences between control and experimental groups were determined using MANOVA. The training effects of the experimental and control groups were determined using the ANOVA for repeated measurements with Bonfferoni correction. The results showed that a physical activity program of strength has a better effect on disease regulation in the elderly with metabolic syndrome than a moderate-intensity physical activity program which also has a significant change but in less variables.

3-Iodothyronamine and Derivatives: New Allies Against Metabolic Syndrome?

In the two decades since its discovery, a large body of evidence has amassed to highlight the potential of 3-iodothyronamine (T1AM) as an antiobesity drug, whose pleiotropic signaling actions profoundly impact energy metabolism. In the present review, we recapitulate the most relevant properties of T1AM, including its structural and functional relationship to thyroid hormone, its endogenous levels, molecular targets, as well as its genomic and non-genomic effects on metabolism elicited in experimental models after exogenous administration. The physiological and pathophysiological relevance of T1AM in the regulation of energy homeostasis and metabolism is also discussed, along with its potential therapeutic applications in metabolic disturbances. Finally, we examine a number of T1AM analogs that have been recently developed with the aim of designing novel pharmacological agents for the treatment of interlinked diseases, such as metabolic and neurodegenerative disorders, as well as additional synthetic tools that can be exploited to further explore T1AM-dependent mechanisms and the physiological roles of trace amine-associated receptor 1 (TAAR1)-mediated effects.

Nanoformulations of natural products for management of metabolic syndrome

Metabolic syndrome is a common metabolic disorder which has become a public health challenge worldwide. There has been growing interest in medications including natural products as complementary or alternative choices for common chemical therapeutics regarding their limited side effects and ease of access. Nanosizing these compounds may help to increase their solubility, bioavailability, and promisingly enhance their efficacy. This study, for the first time, provides a comprehensive overview of the application of natural-products-based nanoformulations in the management of metabolic syndrome. Different phytochemicals including curcumin, berberine, Capsicum oleoresin, naringenin, emodin, gymnemic acid, resveratrol, quercetin, scutellarin, stevioside, silybin, baicalin, and others have been nanosized hitherto, and their nanosizing method and effect in treatment and alleviating metabolic syndrome have been reviewed and discussed in this study. It has been discovered that there are several pathways or molecular targets relevant to metabolic disorders which are affected by these compounds. Various natural-based nanoformulations have shown promising effect in treatment of metabolic syndrome, and therefore can be considered as future candidates instead of or in conjunction with pharmaceutical drugs if they pass clinical trials successfully.

Cannabinoids in health and disease: pharmacological potential in metabolic syndrome and neuroinflammation

The use of different natural and/or synthetic preparations of Cannabis sativa is associated with therapeutic strategies for many diseases. Indeed, thanks to the widespread diffusion of the cannabinoidergic system in the brain and in the peripheral districts, its stimulation, or inhibition, regulates many pathophysiological phenomena. In particular, central activation of the cannabinoidergic system modulates the limbic and mesolimbic response which leads to food craving. Moreover, cannabinoid agonists are able to reduce inflammatory response. In this review a brief history of cannabinoids and the protagonists of the endocannabinoidergic system, i.e. synthesis and degradation enzymes and main receptors, will be described. Furthermore, the pharmacological effects of cannabinoids will be outlined. An overview of the involvement of the endocannabinoidergic system in neuroinflammatory and metabolic pathologies will be made. Finally, particular attention will also be given to the new pharmacological entities acting on the two main receptors, cannabinoid receptor type 1 (CB1) and cannabinoid receptor type 2 (CB2), with particular focus on the neuroinflammatory and metabolic mechanisms involved.

Relation of insulin resistance to neurocognitive function and electroencephalography in obese children

BACKGROUND

Childhood obesity may lead to neuronal impairment in both the peripheral and the central nervous system. This study aimed to investigate the impact of obesity and insulin resistance (IR) on the central nervous system and neurocognitive functions in children.

METHODS

Seventy-three obese children (38 male and 35 female) and 42 healthy children (21 male and 21 female) were recruited. Standard biochemical indices and IR were evaluated. The Wechsler Intelligence Scale for Children-Revised (WISC-R) and electroencephalography (EEG) were administered to all participants. The obese participants were divided into two groups based on the presence or absence of IR, and the data were compared between the subgroups.

RESULTS

Only verbal scores on the WISC-R in the IR+ group were significantly lower than those of the control and IR- groups. There were no differences between the groups with respect to other parameters of the WISC-R or the EEG. Verbal scores of the WISC-R were negatively correlated with obesity duration and homeostatic model assessment-insulin resistance (HOMA-IR) values. EEGs showed significantly more frequent 'slowing during hyperventilation' (SDHs) in obese children than non-obese children.

CONCLUSIONS

Neurocognitive functions, particularly verbal abilities, were impaired in obese children with IR. An early examination of cognitive functions may help identify and correct such abnormalities in obese children.

Effects of prolonged exercise versus multiple short exercise sessions on risk for metabolic syndrome and the atherogenic index in middle-aged obese women: a randomised controlled trial

BACKGROUND

Many people, although they may recognise the positive effects of exercise, do not exercise regularly owing to lack of time. This study aimed to investigate the effects of prolonged single-session exercise and multiple short sessions of exercise on the risk of metabolic syndrome and the atherogenic index in middle-aged obese women.

METHODS

Thirty-six participants were divided into the single-session group, multiple-session group, and control group. The single-session group engaged in one session of treadmill exercise for 30 min a day; the multiple-session group had three sessions of 10 min a day. Both groups exercised 3 days/week for 12 weeks. The control group did not perform any exercise.

RESULTS

The single-session group showed decreases in weight (0.97 kg [95% C.I. = 0.09-1.83], p < .05), body mass index (0.43 kg/m2 [95% C.I. = 0.03-0.81], p < .05), and fat mass (1.65 kg, [95% C.I. = 0.78-2.51], p < .01). Systolic blood pressure dropped in the single-session group (6.66 mmHg, [95% C.I. = 1.44-11.88], p < .05), and diastolic blood pressure dropped in the multiple-session group (3.38 mmHg, [95% C.I. = 1.44-5.88], p < .01). High-density lipoprotein cholesterol rose in the single-session group (4.08 mg/dL, [95% C.I. = -8.08-(-)0.07], p < .05) and dropped in the control group (10.75 mg/dL [95% C.I. = 1.95-19.54], p < .01). According to post hoc analysis, high-density lipoprotein cholesterol increased more in the single-session group than the control group (95% C.I. = 0.61-21.88, p < .05). Glucose levels decreased in both the single-session group (16 mg/dL [95% C.I. = 5.64-26.35], p < .01) and the multiple-session group (12.16 mg/dL, [95% C.I. = 2.18-22.14], p < .05). Waist circumference decreased in the single-session group (2.65 cm [95% C.I. = 1.46-3.83], p < .001) and multiple-session group (2.04 cm, [95% C.I. = 1.51-2.73], p < .001). Low-density lipoprotein cholesterol levels rose in both the multiple-session group (-15.79 mg/dL [95% C.I. = -34.24-(-)3.78], p < .05) and the control group (-22.94 mg/dL [95% C.I. = -44.63-(-)1.24], p < .05). The atherogenic index increased in the control group (-1.06 [95% C.I. = -1.69-(-)0.41], p < .01).

CONCLUSIONS

The findings indicate that prolonged exercise is superior to multiple short sessions for improving the risk of metabolic syndrome and the atherogenic index in middle-aged obese women. However, multiple short sessions can be recommended as an alternative to prolonged exercise when the goal is to decrease blood glucose or waist circumference.

Metabolic syndrome: pathophysiology, management, and modulation by natural compounds

Metabolic syndrome (MetS) represents a cluster of metabolic abnormalities that include hypertension, central obesity, insulin resistance, and atherogenic dyslipidemia, and is strongly associated with an increased risk for developing diabetes and atherosclerotic and nonatherosclerotic cardiovascular disease (CVD). The pathogenesis of MetS involves both genetic and acquired factors that contribute to the final pathway of inflammation that leads to CVD. MetS has gained significant importance recently due to the exponential increase in obesity worldwide. Early diagnosis is important in order to employ lifestyle and risk factor modification. Here, we review the epidemiology and pathogenesis of MetS, the role of inflammation in MetS, and summarize existing natural therapies for MetS.

Insulin resistance among obese middle-aged is associated with decreased cerebrovascular reactivity

OBJECTIVE

To evaluate differences in cerebrovascular reactivity (CVR) to mild hypercapnia in obese/overweight individuals with and without insulin resistance (IR) compared to comparable lean controls.

METHODS

A total of 60 cognitively normal participants (20 lean controls and 24 obese/overweight individuals with and 16 without IR) were evaluated using a high spatial resolution arterial spin labeling MRI technique at rest and during mild hypercapnia. We analyzed group differences in CVR in cerebral cortex and ascertained the relationships between CVR, IR, and body mass index (BMI).

RESULTS

Obese/overweight participants with and without IR had significantly lower CVR to hypercapnia than lean controls after controlling for age, sex, and the presence of hypertension (F_2,53 = 5.578, p = 0.006 [Formula: see text] = 0.174). In the obese/overweight participants with IR, there was a significant correlation between higher CVR and a measure of insulin sensitivity, even after accounting for BMI (r_p = 0.575, p = 0.004). In contrast, there was no relationship between CVR and BMI when controlling for IR. No such relationships existed for the other 2 groups.

CONCLUSIONS

IR is associated with impaired CVR; the relationship appears to be driven by the degree of IR and not by obesity. These rarely reported results suggest that early forms of cerebrovascular dysfunction exist among obese middle-aged individuals with significant IR but without type 2 diabetes mellitus. These functional vascular abnormalities may help explain the associations among IR, diabetes, and dementia, and suggest that interventions aiming to improve IR or CVR may help prevent cognitive decline later in life.

Association between obstructive sleep apnea severity and endothelial dysfunction in patients with type 2 diabetes

Background

Obstructive sleep apnea (OSA) and type 2 diabetes (T2D) are associated with endothelial dysfunction a main predictor of late cardiovascular (CV) events. Despite the high prevalence of OSA in patients with T2D, the impact of OSA severity on endothelial function has not been clearly elucidated. The aim of this cross-sectional study was to determine whether increasing OSA severity is associated with poorer endothelial function in patients with T2D.

Methods

140 patients with T2D and no overt CV disease underwent polysomnography, peripheral arterial tonometry, clinic blood pressure (BP) measurement, biological assessment for CV risk factors, daytime sleepiness and health related quality of life (HRQL) questionnaires. The following commonly used cut-offs for apnea-hypopnea index (AHI) were used to define 3 categories of disease severity: AHI < 15 (no OSA or mild OSA), 15 ≤ AHI < 30 (moderate OSA), and AHI ≥ 30 (severe OSA). The primary outcome was the reactive hyperemia index (RHI), a validated assessment of endothelial function.

Results

21.4% of patients had moderate OSA and 47.6% had severe OSA. Increasing OSA severity and nocturnal hypoxemia were not associated with a significant decrease in RHI. Endothelial dysfunction (RHI < 1.67) was found in 47.1, 44.4 and 39.2% of patients with no OSA or mild OSA, moderate OSA and severe OSA, respectively (p = 0.76). After adjustment for confounders including body mass index, increasing OSA severity was associated with higher systolic BP (p = 0.03), lower circulating levels of adiponectin (p = 0.0009), higher levels of sP-selectin (p = 0.03), lower scores in 3 domains of HRQL including energy/vitality (p = 0.02), role functioning (p = 0.01), and social functioning (p = 0.04).

Conclusions

Moderate to severe OSA is very common but has no impact on digital micro-vascular endothelial function in patients with T2D.

Prevalence of diabetes and obesity in association with prematurity and growth restriction

Intrauterine growth restriction (IUGR) is when fetuses and newborn infants have not reached their true growth potential as genetically defined. Fetuses with IUGR develop in a less than ideal environment that leads to epigenetic changes and marks infants' metabolism for the rest of their lives. Epigenetic changes affect insulin-like growth factor-1 (IGF-1) levels and lead to insulin resistance and ultimately to a metabolic syndrome. The metabolic syndrome is a constellation of illnesses that raise one's risk for type 2 diabetes mellitus, coronary artery disease, and ischemic heart disease, including hypertension, dyslipidemia, central obesity, insulin resistance, and inflammation. The association between IUGR or prematurity and long-term insulin resistance, obesity, hypertension, and metabolic syndrome remains unclear. While studies have shown an association, others have not supported such association. If alteration of intrauterine growth can ultimately lead to the development of metabolic derangements in childhood and adulthood, and if such association is true, then early interventions targeting the health of pregnant women will ensure the health of the population to follow.

Metabolic syndrome in children (Review)

Metabolic syndrome (MetS) is a cluster of cardiometabolic risk factors, including central obesity, insulin resistance, glucose intolerance, dyslipidemia and increased blood pressure. The prevalence of MetS is on the increase worldwide owing to the epidemic of overweight and obesity. The risk of prevalence of MetS greatly increases during adulthood for those children exposed to cardiometabolic risk factors in their early lives. MetS has also been associated with liver fat accumulation in children. Elevated levels of plasma alanine aminotransferase and γ-glutamyl transferase have been associated with liver fat accumulation. The present review aimed to expand knowledge on the clustering of cardiometabolic risk factors responsible for the widespread occurrence of metabolic disease in children.

Review: The metabolic syndrome as an endocrine disease: is there an effective pharmacotherapeutic strategy optimally targeting the pathogenesis?

The metabolic syndrome (MetS) represents a combination of cardiovascular risk determinants such as obesity, insulin resistance and lipid abnormalities such as hypertriglyceridemia, increased free fatty acids, low high-density-cholesterol and hypertension. As a multiple component condition it imparts a doubling of relative risk for atherosclerotic cardiovascular disease (ASCVD). It is currently controversial which component of the syndrome carries what weight. There is even a considerable debate whether the risk for ASCVD is greater in patients diagnosed with MetS than that by the individual risk factors. At present, no unifying pathogenetic mechanism can explain the metabolic syndrome and there is no unique treatment for it. This review summarizes and critically reviews the currently available clinical and scientific evidence for the concept that the MetS is causally an endocrine disease and discusses pharmacotherapeutic strategies targeting the pathogenesis rather than single symptoms of the cluster.

The Metabolic Syndrome and Its Influence on Nonalcoholic Steatohepatitis

Nonalcoholic steatohepatitis (NASH) and the metabolic syndrome (MetS) are highly prevalent in the Western population. Their pathogenesis is closely linked to insulin resistance, which serves as a therapeutic target for the management of these conditions. This review article reviews the research supporting the influence of MetS on NASH and includes studies supporting their similar epidemiology, pathogenesis, and treatment.

Relationship between high normal TSH levels and metabolic syndrome components in type 2 diabetic subjects with euthyroidism

Objective

Thyroid hormones as modulators of adaptive thermogenesis can potentially contribute to development of obesity. The purpose of our study is to observe a relationship between TSH and BMI, blood lipids, BP and HbA1c in type 2 diabetic subjects with euthyroidism.

Methods

A total of 120 subjects with type 2 diabetes were recruited for this study from November 2012 to June 2014. Subjects were included in the study with TSH values between 0.4 and 4.5 mU/l, who did not take any thyroid medication and had a similar iodine diet. Subjects were weighed and anthropometric indices, lipid parameters, fasting plasma glucose, HbA1c, eGFR, blood pressure (BP) were documented. TSH was measured by an electrochemiluminescence immunoassay. Statistical analysis was performed by using SPSS 18(P value <0.05 was considered significant).

Results

The mean age of the participants was 60.6 ± 11.6 years with a BMI of 25.3 ± 3.1 kg/m². Serum TSH levels were significantly and positively associated with BMI, systolic and diastolic BP, serum triglyceride and HbA1c levels, whereas negatively with eGFR. Subjects with a TSH in a higher normal range (2.5–4.5 mU/I, n = 58) had a significantly higher BMI (26.7 ± 3 vs. 24.1 ± 2.7) and this relation remained significant adjusted for age and sex (P < 0.001). When TSH was in low normal range, the number of patients with glycemic goal (HbA1c > 7%) decreased from 27.5% to 12.5% (P = 0.02, adjusted for age and sex).

Conclusion

In type 2 diabetic subjects with biochemical euthyroidism we found significant association between high normal TSH levels and components of metabolic syndrome. High normal TSH levels were associated with more number of subjects with glycemic goal (HbA1c >7%).

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We report TSH levels association with MetS components in type 2 diabetic subjects.

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Diabetes control was somehow complicated in subjects with high-normal TSH levels.

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We suggest low normal TSH concentrations in insulin-resistant subjects.

Lifestyle modification and endothelial function in obese subjects

The metabolic syndrome is a cluster of metabolic and vascular abnormalities that include central obesity, insulin resistance, hyperinsulinemia, glucose intolerance, hypertension, dyslipidemia, hypercoagulability and an increased risk of coronary and cerebral vascular disease. These metabolic and vascular abnormalities are the main cause of cardiovascular mortality in western societies. Endothelial dysfunction, an early step in the development of atherosclerosis, has been reported in obese nondiabetic individuals and in patients with Type 2 diabetes. It has also been observed in individuals at high risk for Type 2 diabetes, including those with impaired glucose tolerance and the normoglycemic first-degree relatives of Type 2 diabetic patients. Recent evidence points to adipocytes as a complex and active endocrine tissue whose secretory products, including free fatty acids and several cytokines (i.e., leptin, adiponectin, tissue necrosis factor-alpha, interleukin-6, and resistin) play a major role in the regulation of human metabolic and vascular biology. These adipocytokines have been claimed to be the missing link between insulin resistance and cardiovascular disease. Interventions designed to improve endothelial and/or adipose-tissue functions may reduce cardiovascular events in obese individuals with either the metabolic syndrome or Type 2 diabetes. Lifestyle modification in the form of caloric restriction and increased physical activity are the most common modalities used for treating those individuals at risk and is unanimously agreed to be the initial step in managing Type 2 diabetes. Several recent studies have demonstrated favorable impacts of lifestyle modifications in improving endothelial function and insulin sensitivity, in addition to altering serum levels of adipocytokines and possibly reducing cardiovascular events. This review discusses current knowledge of the role of lifestyle modifications in ameliorating cardiovascular risk in obese subjects with either the metabolic syndrome or Type 2 diabetes.

Retinal vessel abnormalities as a possible biomarker of brain volume loss in obese adolescents

OBJECTIVE

Endothelial dysfunction in childhood obesity may precede cerebrovascular damage and cognitive impairment in adulthood. A noninvasive proxy of microvascular health is required to identify the risk for microvascular damage in obese children.

DESIGN AND METHODS

The associations of hippocampal volumes and global cerebral atrophy were assessed with retinal vessel caliber in 40 normal BMI controls and 62 obese age-matched nondiabetic adolescents and the contribution of inflammation, obesity, and insulin resistance to retinal vessel caliber was evaluated.

RESULTS

Compared to controls, obese adolescents had smaller retinal arterioles (8.3% decrease, P < 0.05) and wider venules (5.4% increase, P < 0.01). Larger retinal arteriole diameters were associated with less global cerebral atrophy (B = -0.24 [95% confidence interval, CI: -0.48, -0.002]) and larger hippocampal volumes (B = 0.01 [95% CI: 0, 0.02]). Venule diameters (B = 84.2 [95% CI: 30.3, 138.1]) were predicted by inflammation (fibrinogen). Arteriolar diameters were predicted by insulin resistance, indicated by logHOMA (homeostatic model assessment, HOMA) values (B = -17.03 [95% CI: -28.25, -5.81)] and body mass index (BMI) (B = -.67 [95% CI: -1.09, -0.24)]. All analyses were adjusted for mean arterial pressure, sleep apnea, and vessel diameter.

CONCLUSIONS

Measures of brain health, BMI, and insulin resistance are associated with retinal vessel caliber. If confirmed in larger studies, retinal arteriolar caliber may serve as a possible noninvasive proxy for brain atrophy in obese adolescents, and the identification of elevated risk for cerebral microvascular disease in adulthood.

Diabetes alters the expression of partial vasoactivators in cerebral vascular disease susceptible regions of the diabetic rat

BACKGROUND

The pathogenesis between cerebral vascular disease (CVD) and the endothelial dysfunction (ETD) remains elusive in diabetes. Therefore, we investigated the expression of partial vasoactivators which be closely relative to ETD in CVD susceptible brain regions in the diabetic rat. The aim was to search some possible pathogenesis.

METHODS

Diabetes was induced by a single intraperitoneal injection of streptozotocin and a high lipid/sugar diet. The expression of vasoactivators ET-1, CGRP, VCAM-1, ICAM-1 and P-selectin were assessed by immunohistochemical staining and measurement of optic density of positive cells in the frontal and temporal lobe, basal ganglia and thalamus at 4 weeks after establishment of the diabetic model.

RESULTS

The expression of ET-1, VCAM-1, ICAM-1 and P-selectin significantly increased and CGRP significantly decreased in the diabetic group, and the expression of these vasoactivators was significantly different among the frontal, temporal lobe, basal ganglia and thalamus, and among the emotion, splanchno-motor and neuroendocrine center in the diabetic group.

CONCLUSIONS

Diabetes alters the expression of partial vasoactivators in cerebral vascular disease susceptible regions of the diabetic rat. Therefore, we suggested that CVD complications in diabetes are partly caused by ETD via an imbalance expression of endothelial vasoactivators, which might be associated with dysfunction of emotion, autonomic nerve and endocrine center. However, further studies are warranted.

Insulin resistance is not necessarily an essential element of metabolic syndrome

Type 2 diabetes is frequently associated with metabolic syndrome (MetS). Insulin resistance (IR) is thought to be the underlying pathophysiology of MetS. The purpose of this study is to examine the association of MetS with IR and beta cell function. This is a cross-sectional study in NHANES 1999-2000 participants who were at least 18 years old, including 911 non-Hispanic whites (NHW), 398 non-Hispanic blacks (NHB), and 595 Mexican-Americans (MA). MetS was defined based on the revised ATP III. IR and beta cell function were calculated using homeostasis model assessment (HOMA-IR and HOMA-B). The high-risk tertile was defined as the highest HOMA-IR and lowest HOMA-B. The odds ratio (OR) was calculated against the other two tertiles. The relationship of HOAM-IR and HOMA-B with the components of MetS was also examined. IR was a risk factor of MetS in all three ethnic groups (OR 4.17-12.01, P < 0.0001). Fasting glucose, triglycerides, and HDL cholesterol were associated with IR (P < 0.001) and correlated with HOMA-IR (P < 0.001), while inconsistent results were noted in blood pressure and waist circumference among three racial/ethnic groups. However, in the MetS subjects, 32 % of NHW, 28 % of NHB, and 44 % of MA were not in the IR tertile and in the IR subjects, 25 % of NHW, 36 % NHB, and 30 % of MA did not have MetS. No relationship was found between beta cell function and MetS. Although IR is a risk factor for MetS, IR is neither necessary nor required for MetS.

Endothelial dysfunction and insulin resistance

In this article, we review several mechanisms by which insulin resistance is related to endothelial dysfunction. The mechanisms we discuss may explain the high prevalence of cardiovascular disease found in people with the metabolic syndrome and diabetes mellitus.

Impact of metabolic syndrome on cognition and brain: a selected review of the literature

Metabolic syndrome (MetS), a clustering of risk factors for type 2 diabetes mellitus and cardiovascular disease, has been associated with cognitive dysfunction and brain abnormalities. This review describes the literature on the impact of MetS on brain and cognition and suggests directions for future research. A literature search for reports of MetS and cognition and brain imaging was conducted for both nonelderly adults and adolescents. No studies were found describing MetS and brain or cognition among adolescents; therefore, we also included studies investigating individual components of MetS in this age group. Most studies found associations between MetS and cognitive dysfunction. Multiple cognitive domains were affected by MetS in adults. In adolescents, the majority of findings were in executive functioning. Brain imaging literature in adults implicated MetS in ischemic stroke, white matter alterations, and altered brain metabolism. For adolescents, individual MetS factors were linked to volume losses in the hippocampus and frontal lobes. MetS negatively impacts cognitive performance and brain structure. Potential explanatory models include impaired vascular reactivity, neuroinflammation, oxidative stress, and abnormal brain lipid metabolism. We posit that insulin resistance-associated impairment in cerebrovascular reactivity is an important mechanism underlying brain deficits seen in MetS.

Epigenetic manifestation of metabolic syndrome and dietary management

SIGNIFICANCE

Metabolic syndrome constitutes a group of disorders such as insulin resistance, hypertension, and hypertriglyceridemia, predisposing an individual to risk factors such as cardiovascular disease, diabetes, obesity, and dyslipidemia. A majority of these diseases are influenced by the environmental factors, nutrient uptake, and genetic profile of an individual that together dysregulate gene function. These genetic and nongenetic factors are reported to introduce epigenetic cues that modulate the gene function which is inherited by the offspring.

RECENT ADVANCES

Considering the epigenetic modulation of the metabolic disorders, nutrigenomics has been distinctly categorized as a branch that deals with modulatory effect of nutrients on metabolic disorders and disease progression by supplementing the individuals with key nutrient-enriched diets which are derived from plant and animal sources.

CRITICAL ISSUES

Nutritional components of the diet regulate the metabolic health of an individual either by controlling the expression of some key genes related to metabolic pathways or by modulating the epigenetic events on such genes. The present article discusses various metabolic disorders in detail and the effect of nutrients on the specific genes causing those disorders. We also highlight the molecular mechanisms of some metabolic disorders through epigenetic modifications and possible therapeutic interventions.

FUTURE DIRECTIONS

With the advent of high-throughput technologies and epigenetic modulation of the metabolic disorders, an altered epigenetic code that is programmed due to improper nutrients can be reverted back by supplementing the diet with various plant-derived compounds. The implication of small molecular drugs is also of utmost significance for challenging the metabolic disorders.

The endothelin receptor antagonist bosentan improves peripheral endothelial function in patients with type 2 diabetes mellitus and microalbuminuria: a randomised trial

AIMS/HYPOTHESIS

Endothelial dysfunction is important in the development of vascular complications in diabetes. Patients with type 2 diabetes have increased production of the vasoconstrictor and pro-inflammatory peptide, endothelin-1. Short-term intra-arterial administration of endothelin antagonists improves endothelium-dependent vasodilatation in patients with type 2 diabetes. We tested the hypothesis that oral administration of the dual endothelin receptor antagonist, bosentan, improves peripheral endothelial function in patients with type 2 diabetes and microalbuminuria.

METHODS

This placebo-controlled and double-blind study was performed on 46 patients with type 2 diabetes and microalbuminuria (urine albumin/creatinine ratio >3 mg/mmol) at a medical university department. Patients were randomised to bosentan, 125 mg two times per day (n = 28), or placebo (n = 28) for 4 weeks. The computer-generated randomisation code was kept in sealed envelopes. Patients and people doing examinations or assessing outcomes were blinded. The primary endpoint was change in microvascular endothelium-dependent vasodilatation, based on change in digital reactive hyperaemia index. The secondary endpoint was change in brachial artery flow-mediated vasodilatation.

RESULTS

Reactive hyperaemia index increased from 1.73 ± 0.43 (mean ± SD) at baseline to 2.08 ± 0.59 at follow-up (p < 0.05) in the bosentan group (n = 22), but did not change in the placebo group (1.84 ± 0.49 to 1.87 ± 0.47; n = 24). The change in reactive hyperaemia index from baseline was greater in the bosentan group than in the placebo group (p < 0.05). Nitroglycerine-induced digital hyperaemia was not affected. Brachial artery flow-mediated vasodilatation and blood pressure did not change during treatment.

CONCLUSIONS/INTERPRETATION

Oral treatment of 4 weeks duration with the dual endothelin receptor antagonist, bosentan, improves peripheral endothelial function in patients with type 2 diabetes and microalbuminuria.

The metabolic syndrome and risk of chronic kidney disease: pathophysiology and intervention strategies

Metabolic syndrome is characterized by a clustering of cardiovascular risk factors, including abdominal obesity, elevated blood pressure and glucose concentrations, and dyslipidemia. The presence of this clinical entity is becoming more pervasive throughout the globe as the prevalence of obesity increases worldwide. Moreover, there is increased recognition of the complications and mortality related to this syndrome. This paper looks to examine the link between metabolic syndrome and the development of chronic kidney disease.

Prevalence of calcified carotid artery atheromas on the panoramic images of patients with syndrome Z, coexisting obstructive sleep apnea, and metabolic syndrome

OBJECTIVES

The objective of this study was to compare the prevalence of calcified carotid artery atheromas (CCAAs) on panoramic images of individuals (n = 31) with obstructive sleep apnea (OSA) with individuals (n = 117) with syndrome Z (SZ: OSA with concomitant metabolic syndrome [MetS]).

STUDY DESIGN

Images of patients with OSA or SZ referred from the Sleep Service to Dentistry were evaluated. Descriptive statistics and t tests (Bonferroni correction) were conducted to determine significant differences between atheroma prevalence and proatherogenic factors (age, apnea-hypopnea index, body mass index, lipid profile, blood pressure, glucose) between OSA and SZ groups.

RESULTS

Individuals with OSA had an atheroma prevalence of 35% and those with SZ 42% (P = .52). Individuals with SZ also had significantly more severe atherogenic profiles (obesity, dyslipidemia, hyperglycemia) than OSA patients (P ≤ .05). Greatest CCAA prevalence (63%) was evidenced by SZ patients with severe OSA and moderate MetS.

CONCLUSION

Individuals with SZ have significantly greater atherogenic burden and slightly higher prevalence of CCAAs when compared with individuals with OSA.

Type 2 diabetes affects hippocampus volume differentially in men and women

BACKGROUND

Type 2 diabetes mellitus (T2DM) has been shown to result in medical complications on several organ systems including the kidneys, eyes, cardiovascular system, and most recently described the brain, including the hippocampus. There is also evidence that females are disproportionately affected by these medical complications. Brain volume reductions have also been associated with chronic low-grade inflammation and dyslipidaemia. This study investigated the relationships among T2DM, gender, inflammation, dyslipidaemia, and hippocampal volumes.

METHOD

Participant groups consisted of 40 obese adults with T2DM and 47 lean adults, group-matched on age, gender, race, and education. Each participant underwent medical examination including a standard panel of blood tests, a magnetic resonance imaging, and cognitive evaluation.

RESULTS

We show that there is a gender difference in the association of T2DM and hippocampal volumes: diabetic women are most affected despite having better glucose control than their male counterparts. Although females with T2DM had disproportionately lower high density lipoprotein as well as better haemoglobin A1c, neither of these results explained why females with T2DM had the smallest hippocampal volumes.

CONCLUSIONS

These important findings indicate that in addition to the higher rate of traditional medical complication, females with T2DM are likely to suffer more brain complications than males. These observations, if supported by larger studies, suggest that in the future gender could be considered when customizing diabetes treatment.

Endotelium in Turner syndrome with capillaroscopy

OBJECTIVE: The aim of this study was to assess the endothelium function in patients with Turner syndrome using videocapillaroscopy and to compare the results with healthy control. METHODS: Subjects and controls were studied in a temperature-controlled room, 20 days after no nailfold manipulations. The capillaries were visualized by a microscope connected to a television and a computer. The test of post-occlusive reactive hyperemia was performed using a sphygmomanometer attached to the fourth left finger, 20mmHg above maximum arterial pressure during 1 minute, and the following patterns were studied: area of transverse segment, maximal post-ischemia area and time to reach maximal post-ischemia area. RESULTS: The value of measure of transverse segment projected area , the maximal postischemia area of hand nailfold capillary loops using computerized videophotometry and the time to reach maximal post ischemia area were studied in 40 patients with Turner syndrome and 26 healthy women controls of comparable age (20±7.5 versus 18±8.1 years old; p=0.57). There were differences between transverse segment area (706.8±139.1 versus 548.8±117.2; p=0.001). Maximal post-ischemia area (891.3±226.1 versus 643.5±134.3; p=0.001) and the time to reach it (10.8±4.3 versus 5.5±2.5; p=0.001) were different between patients and controls. CONCLUSIONS: Changes of capillary response to ischemia could be observed in patients with Turner syndrome using videocapillaroscopy when they were compared to a healthy control group.

Prevalence of comorbid obstructive sleep apnea and metabolic syndrome: syndrome Z and maxillofacial surgery implications

PURPOSE

To determine the prevalence of the recently identified syndrome Z (SZ), which is the co-occurrence of obstructive sleep apnea (OSA; hypoxia, systemic and pulmonary hypertension, nocturnal arrhythmias) and metabolic syndrome (MetS; increased abdominal girth, hypertriglyceridemia, decreased high-density lipoprotein, hypertension, increased fasting glucose), which places the surgical patient at heightened risk of perioperative complications (myocardial infarction, stroke, pneumonia, wound infection).

MATERIALS AND METHODS

Electronic medical records of 296 male veterans were assessed for the presence of SZ using the American Academy of Sleep Medicine definition of OSA and a modified Adult Treatment Panel III definition of MetS, where obesity was defined by a body mass index of at least 30 kg/m(2) rather than by waist circumference.

RESULTS

SZ was diagnosed in 59% of patients. These individuals commonly exhibited severe OSA and least commonly mild OSA. The more severe the OSA, the more likely (60%) that patients manifested moderate (4 risk markers) or severe (5 risk markers) MetS. Furthermore, with increasing apnea-hypopnea index values, the more severe were the MetS elements.

CONCLUSIONS

The results of this study demonstrate the high prevalence rate of MetS in patients with OSA seeking treatment. Given the risk of perioperative complications, it is suggested that all patients scheduled for maxillofacial surgical procedures to treat OSA be evaluated for SZ.

Association analysis of urotensin II gene (UTS2) and flanking regions with biochemical parameters related to insulin resistance

Background

Urotensin II (UII) is a potent vasoconstrictor peptide, which signals through a G-protein coupled receptor (GPCR) known as GPR14 or urotensin receptor (UTR). UII exerts a broad spectrum of actions in several systems such as vascular cell, heart muscle or pancreas, where it inhibits insulin release.

Objective

Given the reported role of UII in insulin secretion, we have performed a genetic association analysis of the UTS2 gene and flanking regions with biochemical parameters related to insulin resistance (fasting glucose, glucose 2 hours after a glucose overload, fasting insulin and insulin resistance estimated as HOMA).

Results and Conclusions

We have identified several polymorphisms associated with the analysed clinical traits, not only at the UTS2 gene, but also in thePER3 gene, located upstream from UTS2. Our results are compatible with a role for UII in glucose homeostasis and diabetes although we cannot rule out the possibility that PER3 gene may underlie the reported associations.

Obese Adolescents with Type 2 Diabetes Mellitus Have Hippocampal and Frontal Lobe Volume Reductions

The rates of type 2 diabetes (T2DM) continue to parallel the rising rates of obesity in the United States, increasingly affecting adolescents as well as adults. Hippocampal and frontal lobe reductions have been found in older adults with type 2 diabetes, and we sought to ascertain if these brain alterations were also present in obese adolescents with T2DM. In a cross-sectional study we compared MRI-based regional brain volumes of 18 obese adolescents with T2DM and 18 obese controls without evidence of marked insulin resistance. Groups were matched on age, sex, school grade, ethnicity, socioeconomic status, body mass index, and waist circumference. Relative to obese controls, adolescents with T2DM had significantly reduced hippocampal and prefrontal volumes, and higher rates of global cerebral atrophy. Hemoglobin A1c, an index of long-term glycemic control, was inversely associated with prefrontal volume and positively associated with global cerebral atrophy (both p < 0.05). Brain integrity is negatively impacted by T2DM already during adolescence, long before the onset of overt macrovascular disease. Paralleling the findings of greater vascular and renal complications among obese adolescents with severe insulin resistance and T2DM relative to their age-matched peers with type 1 diabetes, we find clear evidence of possible brain complications. Our findings call for aggressive and early intervention to limit the negative impact of obesity-associated insulin resistance leading to T2DM on the developing brains of adolescents.

Preliminary evidence for brain complications in obese adolescents with type 2 diabetes mellitus

AIMS/HYPOTHESIS

Central nervous system abnormalities, including cognitive and brain impairments, have been documented in adults with type 2 diabetes who also have multiple co-morbid disorders that could contribute to these observations. Assessing adolescents with type 2 diabetes will allow the evaluation of whether diabetes per se may adversely affect brain function and structure years before clinically significant vascular disease develops.

METHODS

Eighteen obese adolescents with type 2 diabetes and 18 obese controls without evidence of marked insulin resistance, matched on age, sex, school grade, ethnicity, socioeconomic status, body mass index and waist circumference, completed MRI and neuropsychological evaluations.

RESULTS

Adolescents with type 2 diabetes performed consistently worse in all cognitive domains assessed, with the difference reaching statistical significance for estimated intellectual functioning, verbal memory and psychomotor efficiency. There were statistical trends for executive function, reading and spelling. MRI-based automated brain structural analyses revealed both reduced white matter volume and enlarged cerebrospinal fluid space in the whole brain and the frontal lobe in particular, but there was no obvious grey matter volume reduction. In addition, assessments using diffusion tensor imaging revealed reduced white and grey matter microstructural integrity.

CONCLUSIONS/INTERPRETATION

This is the first report documenting possible brain abnormalities among obese adolescents with type 2 diabetes relative to obese adolescent controls. These abnormalities are not likely to result from education or socioeconomic bias and may result from a combination of subtle vascular changes, glucose and lipid metabolism abnormalities and subtle differences in adiposity in the absence of clinically significant vascular disease. Future efforts are needed to elucidate the underlying pathophysiological mechanisms.

Metabolic syndrome and endometrial cancer risk

BACKGROUND

Various studies reported direct associations between endometrial cancer risk and individual components of the metabolic syndrome (MetS), i.e. obesity, diabetes, hypertension, and dyslipidemia, but only a few epidemiological studies considered the association with MetS overall.

METHODS

We analyzed data from a case-control study including 454 women with incident endometrial cancer and 798 controls admitted to the same hospitals as cases for acute conditions. Different definitions of MetS were considered, including a combination of self-reported history of diabetes, drug-treated hypertension, drug-treated hyperlipidemia, and various measures of (central) obesity. Odds ratios (ORs) were computed from unconditional logistic regression models, adjusted for major confounding factors.

RESULTS

The multivariate ORs of endometrial cancer were 2.18 for type 2 diabetes, 1.77 for hypertension, 1.20 for hyperlipidemia, between 1.62 and 2.23 for various definitions of central obesity, and 3.83 for women with a body mass index (BMI) >30 kg/m(2). The risk of endometrial cancer was significantly increased for subjects with MetS, the ORs ranging between 1.67 and 2.77 when waist circumference was included in MetS definition, and 8.40 when BMI was considered instead.

CONCLUSIONS

This study indicates a direct association between various MetS components, besides overweight, with the risk of endometrial cancer.

Dealcoholized red wine reverse vascular remodeling in an experimental model of metabolic syndrome: role of NAD(P)H oxidase and eNOS activity

The present study examines the effect of chronic administration of dealcoholized red wine Malbec (DRW) on vascular remodeling and NAD(P)H oxidase and endothelial nitric oxide synthase activity (eNOS) in an experimental model of metabolic syndrome induced by fructose administration. Thirty-day old male Wistar rats were fed a normal rat diet (control) or the same diet plus 10% fructose in drinking water (FFR). During the last 4 weeks of a 10-week period of the corresponding diet, a subgroup of control and FFR (n=8 each) received DRW in their drinking water. Systolic blood pressure (SBP), a homeostasis model assessment of insulin resistance (HOMA-IR), aortic NAD(P)H oxidase and eNOS activity in the heart and vascular tissue were evaluated. Vascular remodeling was evaluated in the left carotid artery (CA) and interlobar, arcuate and interlobular renal arteries (RA) through lumen to media (L/M) ratio determination. At the end of the study FFR increased the SBP (p < 0.001), HOMA-IR (p < 0.001), and aortic NAD(P)H oxidase activity (p < 0,05) but reduced cardiac and vascular eNOS activity (p < 0.01), L/M ratio in CA (p < 0.001) and RA (p < 0.01) compared with the C group. DRW reduced SBP (p < 0.05), aortic NAD(P)H oxidase (p < 0.05), and recovered eNOS activity (p < 0.001) and L/M in CA (p < 0.001) and RA (p < 0.001) compared with FFR. This study provides new data about the beneficial effect of DRW on oxidative stress and vascular remodeling in the experimental model of metabolic syndrome. Data suggest the participation of mechanisms involving oxidative stress in FFR alterations and the usefulness of natural antioxidant substances present in red wine in the reversion of these changes.

Management of the metabolic syndrome in cardiovascular disease

The main components of the metabolic syndrome (MS) are abdominal obesity, atherogenic dyslipidemia, raised blood pressure, insulin resistance with or without glucose intolerance, and proinflammatory and prothrombotic states. The clustering of these metabolic risk factors significantly increases the risk of type 2 diabetes and promotes vascular endothelial dysfunction, inflammation, and increased oxidative stress. The net result is an increase in the risk of atherosclerotic cardiovascular disease. Therefore, management of MS is of utmost importance, especially considering its rapidly increasing prevalence in a population with rising obesity rates and its significant cardiovascular implications. The primary management of this syndrome involves the correction of the underlying risk factors--obesity, physical inactivity, and an atherogenic diet--with lifestyle modifications including increased physical activity and dietary modification. Smoking cessation also should be encouraged. However, pharmacologic therapies are often required to address cardiovascular risk factors. These agents can be categorized broadly into 1) anorectic agents, 2) insulin-sensitizing agents, 3) statins, and 4) renin-angiotensin system antagonists. Emerging therapies include adipokines, endocannabinoid inhibitors, and metabolic modulators, such as perhexiline and trimetazidine. To date, these therapies have not been shown to normalize the metabolic and cardiovascular burden of MS, and there still is no single therapeutic agent for its management.

Metabolic syndrome is associated with learning and recall impairment in middle age

AIMS

To determine whether middle-aged individuals with metabolic syndrome, both with and without type 2 diabetes, exhibit cognitive impairments, and to determine the role of each metabolic syndrome component in those associations.

METHODS

143 participants were drawn from ongoing studies of normal aging. Metabolic syndrome was diagnosed in 73 participants (age: 60.4 +/- 8.4 years), who were contrasted with 70 age- and education-matched controls.

RESULTS

Metabolic syndrome was associated with reductions in recall (p = 0.006), lower overall intellectual functioning (p = 0.013), and nearly significant reductions in learning (p = 0.066) and executive functioning (p = 0.050). These effects were only marginally attenuated when controlling for type 2 diabetes diagnosis. Of the 5 components of the metabolic syndrome, insulin resistance was the only significant predictor of variance in learning and recall. In addition, the number of metabolic syndrome criteria met was inversely associated with cognitive performance.

CONCLUSIONS

These results indicate that impairments in cognitive functioning associated with metabolic syndrome and type 2 diabetes may begin as early as middle age and are primarily due to insulin resistance. These results demonstrate the importance of screening at-risk adults for insulin resistance in order to initiate lifestyle modifications to reverse or prevent these cognitive changes.

Role of urotensin II in health and disease

Urotensin II (UII) is an 11 amino acid cyclic peptide originally isolated from the goby fish. The amino acid sequence of UII is exceptionally conserved across most vertebrate taxa, sharing structural similarity to somatostatin. UII binds to a class of G protein-coupled receptor known as GPR14 or the urotensin receptor (UT). UII and its receptor, UT, are widely expressed throughout the cardiovascular, pulmonary, central nervous, renal, and metabolic systems. UII is generally agreed to be the most potent endogenous vasoconstrictor discovered to date. Its physiological mechanisms are similar in some ways to other potent mediators, such as endothelin-1. For example, both compounds elicit a strong vascular smooth muscle-dependent vasoconstriction via Ca2+ release. UII also exerts a wide range of actions in other systems, such as proliferation of vascular smooth muscle cells, fibroblasts, and cancer cells. It also 1) enhances foam cell formation, chemotaxis of inflammatory cells, and inotropic and hypertrophic effects on heart muscle; 2) inhibits insulin release, modulates glomerular filtration, and release of catecholamines; and 3) may help regulate food intake and the sleep cycle. Elevated plasma levels of UII and increased levels of UII and UT expression have been demonstrated in numerous diseased conditions, including hypertension, atherosclerosis, heart failure, pulmonary hypertension, diabetes, renal failure, and the metabolic syndrome. Indeed, some of these reports suggest that UII is a marker of disease activity. As such, the UT receptor is emerging as a promising target for therapeutic intervention. Here, a concise review is given on the vast physiologic and pathologic roles of UII.

Pathogenesis and pathophysiology of the cardiometabolic syndrome

The cardiometabolic syndrome represents a cluster of metabolic abnormalities that are risk factors for cardiovascular disease. The mechanism(s) responsible for developing the cardiometabolic syndrome is not known, but it is likely that multi-organ insulin resistance, which is a common feature of the cardiometabolic syndrome, is involved. Insulin resistance is an important risk factor for type 2 diabetes and can cause vasoconstriction and renal sodium reabsorption, leading to increased blood pressure. Alterations in adipose tissue fatty acid and adipokine metabolism are involved in the pathogenesis of insulin resistance. Excessive rates of fatty acid release into the bloodstream can impair the ability of insulin to stimulate muscle glucose uptake and suppress hepatic glucose production. Noninfectious systemic inflammation associated with adipocyte and adipose tissue macrophage cytokine production can also cause insulin resistance. In addition, increased free fatty acid delivery to the liver can stimulate hepatic very low-density lipoprotein triglyceride production, leading to dyslipidemia.

A blunted cortisol awakening response and hippocampal atrophy in type 2 diabetes mellitus

There is emerging evidence from healthy individuals, as well as direct and indirect evidence from psychiatric and neurological patients with disease-related hippocampal atrophy, linking the cortisol awakening response (CAR) to hippocampal volume. Type 2 diabetes mellitus (T2DM) is a metabolic disease that is also accompanied by hippocampal atrophy, and therefore can serve as a model for ascertaining the relationship between CAR and hippocampal volume. We contrasted a group of 18 individuals with T2DM with 12 matched controls on MRI-based hippocampal volume and salivary diurnal cortisol profile including CAR. Individuals with T2DM had smaller hippocampal volumes and exhibited a blunting of the CAR relative to controls, while diurnal cortisol was not affected. Across all subjects, fasting insulin and hippocampal volume were associated with the CAR, independent of diagnosis. Our findings support the hypothesis that hippocampal integrity is an important predictor of the CAR.

The importance of endothelin-1 for microvascular dysfunction in diabetes

Most of the late diabetic complications such as retinopathy, nephropathy, and neuropathy, have their basis in disturbed microvascular function. Structural and functional changes in the micro-circulation are present in diabetes mellitus irrespective of the organ studied, and the pathogenesis is complex. Endothelial dysfunction, characterized by an imbalance between endothelium-derived vasodilator and vasoconstrictor substances, plays an important role in the pathogenesis of diabetic microangiopathy. Increased circulating levels of endothelin-1 (ET-1), a potent vasoconstrictor peptide, has been found in patients with diabetes, and a positive correlation between plasma ET-1 levels and microangiopathy in patients with type 2 diabetes has been demonstrated. In addition to its direct vasoconstrictor effects, enhanced levels of ET-1 may contribute to endothelial dysfunction through inhibitory effects on nitric oxide (NO) production. Vascular endothelial dysfunction may precede insulin resistance, although the feature of insulin resistance syndrome includes factors that have negative effects on endothelial function. Furthermore, ET-1 induces a reduction in insulin sensitivity and may take part in the development of the metabolic syndrome. In the following, the mechanisms by which ET-1 contributes to the development of diabetic microangiopathy and the potentially beneficial effect of selective ET_A receptor antagonists are discussed.

The metabolic syndrome

The "metabolic syndrome" (MetS) is a clustering of components that reflect overnutrition, sedentary lifestyles, and resultant excess adiposity. The MetS includes the clustering of abdominal obesity, insulin resistance, dyslipidemia, and elevated blood pressure and is associated with other comorbidities including the prothrombotic state, proinflammatory state, nonalcoholic fatty liver disease, and reproductive disorders. Because the MetS is a cluster of different conditions, and not a single disease, the development of multiple concurrent definitions has resulted. The prevalence of the MetS is increasing to epidemic proportions not only in the United States and the remainder of the urbanized world but also in developing nations. Most studies show that the MetS is associated with an approximate doubling of cardiovascular disease risk and a 5-fold increased risk for incident type 2 diabetes mellitus. Although it is unclear whether there is a unifying pathophysiological mechanism resulting in the MetS, abdominal adiposity and insulin resistance appear to be central to the MetS and its individual components. Lifestyle modification and weight loss should, therefore, be at the core of treating or preventing the MetS and its components. In addition, there is a general consensus that other cardiac risk factors should be aggressively managed in individuals with the MetS. Finally, in 2008 the MetS is an evolving concept that continues to be data driven and evidence based with revisions forthcoming.

A relationship between insulin sensitivity and vasodilation in women with a history of preeclamptic pregnancy

Women with a history of preeclampsia are characterized by vascular dysfunction and an increased risk of cardiovascular disease. In the present study we investigated whether insulin sensitivity is decreased in women with previous preeclampsia and whether it is associated with endothelium-dependent and/or -independent vasodilation and/or features of metabolic syndrome. Twenty-eight nonobese women with previous severe preeclampsia and 20 women with a previous normotensive pregnancy were studied 5 to 6 years after the index pregnancy. Vasodilation was measured by venous occlusion plethysmography after intra-arterial infusions of sodium nitroprusside and acetylcholine and insulin sensitivity by the intravenous glucose tolerance test using the minimal model technique. The women were tested for lipid profile, inflammatory status and endothelial activation. Insulin sensitivity did not differ between the groups (P=0.24). Insulin sensitivity correlated positively to endothelium-dependent vasodilation only in the patient group in both low (beta=0.59; P=0.04) and high (beta=0.53; P=0.04) concentrations of acetylcholine and in a high concentration of sodium nitroprusside (beta=0.0007; P=0.006). In multivariate analysis, the waist/hip ratio (P=0.04) and serum triglycerides (P=0.04) had the most effect on insulin sensitivity in the patient group. Gestational weeks at the onset of preeclamptic hypertension (P=0.02) and proteinuria (P=0.02) associated positively with insulin sensitivity together with first-trimester body mass index (P=0.008) and maximum diastolic blood pressure during preeclampsia (P=0.005). The present study indicates a relation between insulin sensitivity with vascular dilatory function in women with previous preeclampsia. Furthermore, early onset preeclampsia correlates with impaired insulin sensitivity later in life.