Differential effect of losartan in female and male spontaneously hypertensive rats

We demonstrated that the decreased response to acetylcholine observed in aorta of male and female spontaneously hypertensive rats is corrected after sustained (15 days) reduction of blood pressure levels by losartan. In order to verify if the same occurs in resistance vessels, vascular diameter changes induced by topical application of acetylcholine and bradykinin (endothelium-dependent vasodilators) and sodium nitroprusside (endothelium-independent vasodilator) to mesenteric arterioles studied in vivo, in situ were determined in rats treated with losartan for 24 h (acute) or 15 days (chronic). Rats that presented similar reduction (in %) of the blood pressure levels after losartan treatment were chosen. Sodium nitroprusside induced similar responses in losartan-treated and untreated male or female SHR. Whereas in female SHR, losartan corrected the diminished arteriolar response to endothelium-dependent vasodilators after acute and chronic treatment, in male SHR this correction only occurred after chronic treatment. Thus, losartan corrected the endothelial dysfunction more easily in female than in male SHR and independently of the normalization or the magnitude of the reduction of the blood pressure levels. In an attempt to explain the difference, we evaluated the losartan effect on nitric-oxide synthase (NOS) activity and angiotensin II AT1 and AT2 receptor gene expression in these animals. In male and female SHR, NOS activity and AT1 receptor expression were not altered by acute or chronic treatment. On the other hand, AT2 receptor expression was augmented only in female SHR by these treatments. Therefore, augmented AT2 receptor expression, but not alteration of NOS activity or AT1 receptor expression, might explain the difference observed.     

Oxidative damages in erythrocytes of patients with metabolic syndrome

The aim of the study was to estimate the changes caused by oxidative stress in structure and function of membrane of erythrocytes from patients with metabolic syndrome (MS). The study involved 85 patients with MS before pharmacological treatment and 75 healthy volunteers as a control group. Cholesterol level, lipid peroxidation, glutathione level (GSH), and antioxidant enzyme activities in erythrocytes were investigated. The damage to erythrocyte proteins was also indicated by means of activity of ATPase (total and Na⁺,K⁺ ATPase) and thiol group level. The membrane fluidity of erythrocytes was estimated by the fluorescent method. The cholesterol concentration and the level of lipid peroxidation were significantly higher, whereas the concentration of proteins thiol groups decreased in the patient group. ATPase and GSH peroxidase activities diminished compared to those in the control group. There were no differences in either catalase or superoxide dismutase activities. The membrane fluidity was lower in erythrocytes from patients with MS than in the ones from control group. These results show changes in red blood cells of patients with MS as a consequence of a higher concentration of cholesterol in the membrane and an increased oxidative stress.     

Reduction of asymmetric dimethylarginine involved in the cardioprotective effect of losartan in spontaneously hypertensive rats

Previous studies have indicated that nitric oxide synthase (NOS) inhibitors can induce an increase of blood pressure and exacerbate myocardial injury induced by ischemia and reperfusion, whereas angiotensin II receptor antagonists protect the myocardium against injury induced by ischemia and reperfusion. Isolated hearts from male spontaneously hypertensive rats (SHR) or male Wistar-Kyoto rats (WKY) were subjected to 20 min global ischemia and 30 min reperfusion. Heart rate, coronary flow, left ventricular pressure, and its first derivatives (+/-dP/dt(max)) were recorded, and serum concentrations of asymmetric dimethylarginine (ADMA) and NO and the release of creatine kinase in coronary effluent were measured. The level of ADMA was significantly increased and the concentration of NO was decreased in SHR. Ischemia and reperfusion significantly inhibited the recovery of cardiac function and increased the release of creatine kinase, and ischemia and reperfusion-induced myocardial injury in SHR was aggravated compared with WKY. Vasodilation responses to acetylcholine of aortic rings were decreased in SHR. Treatment with losartan (30 mg/kg) for 14 days significantly lowered blood pressure, elevated the plasma level of NO, and decreased the plasma concentration of ADMA in SHR. Treatment with losartan significantly improved endothelium-dependent relaxation and cardiac function during ischemia and reperfusion in SHR. Exogenous ADMA also aggravated myocardial injury induced by ischemia and reperfusion in isolated perfused heart of WKY, as shown by increasing creatine kinase release and decreasing cardiac function. The present results suggest that the protective effect of losartan on myocardial injury induced by ischemia and reperfusion is related to the reduction of ADMA levels.     

Metabolic programming: fetal origins of obesity and metabolic syndrome in the adult

Exposure of the fetus to the intrauterine milieu can have profound effects on the health of the offspring in adulthood. Results of a series of studies demonstrate the powerful influence of the mother's metabolic state on whether the emerging adult develops obesity and hyperinsulinemia. Importantly, these attributes can be passed on to the next generation nongenetically and can be reversed and prevented.     

Increased prevalence of metabolic syndrome in patients with acne inversa

Background

Acne inversa (AI; also designated as Hidradenitis suppurativa) is a common chronic inflammatory skin disease, localized in the axillary, inguinal and perianal skin areas that causes painful, fistulating sinuses with malodorous purulence and scars. Several chronic inflammatory diseases are associated with the metabolic syndrome and its consequences including arteriosclerosis, coronary heart disease, myocardial infraction, and stroke. So far, the association of AI with systemic metabolic alterations is largely unexplored.

Methods and Findings

A hospital-based case-control study in 80 AI patients and 100 age- and sex-matched control participants was carried out. The prevalence of central obesity (odds ratio 5.88), hypertriglyceridemia (odds ratio 2.24), hypo-HDL-cholesterolemia (odds ratio 4.56), and hyperglycemia (odds ratio 4.09) in AI patients was significantly higher than in controls. Furthermore, the metabolic syndrome, previously defined as the presence of at least three of the five alterations listed above, was more common in those patients compared to controls (40.0% versus 13.0%; odds ratio 4.46, 95% confidence interval 2.02 to 9.96; P<0.001). AI patients with metabolic syndrome also had more pronounced metabolic alterations than controls with metabolic syndrome. Interestingly, there was no correlation between the severity or duration of the disease and the levels of respective parameters or the number of criteria defining the metabolic syndrome. Rather, the metabolic syndrome was observed in a disproportionately high percentage of young AI patients.

Conclusions

This study shows for the first time that AI patients have a high prevalence of the metabolic syndrome and all of its criteria. It further suggests that the inflammation present in AI patients does not have a major impact on the development of metabolic alterations. Instead, evidence is given for a role of metabolic alterations in the development of AI. We recommend monitoring of AI patients in order to correct their modifiable cardiovascular risk factors.     

Effects of losartan/hydrochlorothiazide on serum uric acid levels and blood pressure in hypertensive patients

The effect of a mixed formulation of 50 mg losartan (LOS) and 12.5 mg hydrochlorothiazide (HCTZ) on blood pressure and the uric acid metabolism was analyzed in 73 patients who switched to this formulation from other antihypertensive drugs. Eight patients who switched to the formulation from the regular dose of renin-angiotensin (RA) inhibitor (angiotensin receptor blocker [ARB] or angiotensin-converting enzyme [ACE] inhibitor) only showed a significant decrease in blood pressure, from 156.9 ± 14.1/88.6 ± 9.7 mmHg to 128.3 ± 16.0/76.1 ±10.7 mmHg (p = 0.007), and a significant increase in serum uric acid levels, from 5.2 ± 1.1 mg/dL to 6.8 ± 0.7 mg/dL (p = 0.02). In the other 50 patients who switched from a combination of the regular dose of RA inhibitor and calcium channel blocker (CCB), their blood pressure significantly increased, from 126.0 ± 13.8/72.0 ± 10.0 mmHg to 132.5 ± 16.4/76.5 ± 11.3 mmHg (p = 0.02), and their serum uric acid levels also significantly increased, from 5.6 ± 1.1 mg/dL to 6.1 ± 1.3 mg/dL (p = 0.0002). Considering that guidelines recommend using antihypertensive therapies that do not lead to an increase in serum uric acid levels, we conclude that using the ARB/HCTZ combination is less suitable than the regular dose of the ARB/CCB combination due to its effect on hypertension and serum uric acid levels.     

Myocardial lipid accumulation in patients with pressure-overloaded heart and metabolic syndrome

We evaluated the role of sterol-regulatory element binding protein (SREBP)-1c/peroxisome proliferator activated receptor-γ (PPARγ) pathway on heart lipotoxicity in patients with metabolic syndrome (MS) and aortic stenosis (AS). Echocardiographic parameters of heart function and structural alterations of LV specimens were studied in patients with (n = 56) and without (n = 61) MS undergoing aortic valve replacement. Tissues were stained with hematoxylin-eosin (H and E) and oil red O for evidence of intramyocyte lipid accumulation. The specimens were also analyzed with PCR, Western blot, and immunohistochemical analysis for SREBP-1c and PPARγ. Ejection fraction (EF) was lower in MS compared with patients without MS (P < 0.001); no difference was found in aortic orifice surface among the groups. H and E and oil red O staining of specimens from MS patients revealed several myocytes with intracellular accumulation of lipid, whereas these alterations were not detected in biopsies from patients without MS. Patients without MS have low levels and weak immunostaining of SREBP-1c and PPARγ in heart specimens. In contrast, strong immunostaining and higher levels of SREBP-1c and PPARγ were seen in biopsies from the MS patients. Moreover, we evidenced a significative correlation between both SREBP-1c and PPARγ and EF and intramyocyte lipid accumulation (P < 0.001). SREBP-1c may contribute to heart dysfunction by promoting lipid accumulation within myocytes in MS patients with AS; SREBP-1c may do it by increasing the levels of PPARγ protein.     

The association of left ventricular hypertrophy with metabolic syndrome is dependent on body mass index in hypertensive overweight or obese patients

Background

Overweight (Ow) and obesity (Ob) influence blood pressure (BP) and left ventricular hypertrophy (LVH). It is unclear whether the presence of metabolic syndrome (MetS) independently affects echocardiographic parameters in hypertension.

Methods

380 Ow/Ob essential hypertensive patients (age ≤65 years) presenting for referred BP control-related problems. MetS was defined according to NCEP III/ATP with AHA modifications and LVH as LVM/h^2.7 ≥49.2 g/m^2.7 in males and ≥46.7 g/m^2.7 in females. Treatment intensity score (TIS) was used to control for BP treatment as previously reported.

Results

Hypertensive patients with MetS had significantly higher BMI, systolic and mean BP, interventricular septum and relative wall thickness and lower ejection fraction than those without MetS. LVM/h^2.7 was significantly higher in MetS patients (59.14±14.97 vs. 55.33±14.69 g/m^2.7; p = 0.022). Hypertensive patients with MetS had a 2.3-fold higher risk to have LVH/h^2.7 after adjustment for age, SBP and TIS (OR 2.34; 95%CI 1.40–3.92; p = 0.001), but MetS lost its independent relationship with LVH when BMI was included in the model.

Conclusions

In Ow/Ob hypertensive patients MetS maintains its role of risk factor for LVH independently of age, SBP, and TIS, resulting in a useful predictor of target organ damage in clinical practice. However, MetS loses its independent relationship when BMI is taken into account, suggesting that the effects on MetS on LV parameters are mainly driven by the degree of adiposity.     

Activated hypothalamic pituitary adrenal axis in patients with metabolic syndrome

Metabolic syndrome (MetS) is correlated with the activity of hypothalamic-pituitary-adrenal axis (HPA), but the underlying mechanism still remains elusive. The aim of this study was to investigate the HPA axis function in patients with MetS. This case-control study included 159 people. They were divided into 2 groups. The first group included 73 healthy volunteers (control group: 19 males, 54 females, mean±SD: 49.9±7.5 years old, with BMI: 27.9±4.42?kg/m2) and the second group included 86 patients with MetS (case group: 48 males, 38 females, mean±SD: 52.2±7.6 years old, with BMI: 30.5±5.35?kg/m2). An oral glucose tolerance test (OGTT) was performed for all subjects after a 12-h overnight fast, and blood samples were obtained for determination of ACTH, cortisol, insulin, C-peptide, and glucose levels. Serum cortisol after an overnight dexamethasone suppression test was determined in both groups. Patients with MetS had serum cortisol levels after an overnight dexamethasone suppression test significantly higher than controls. During OGTT plasma ACTH levels were higher at all time points in patients with MetS compared to controls, whereas serum cortisol levels were comparable between the 2 groups. Plasma ACTH during OGTT was also correlated with most of the components of MetS. The HPA axis in patients with MetS seems to be more active as evidenced by the higher cortisol levels after the overnight dexamethasone suppression test and by the higher ACTH levels during OGTT. This functional hypercortisolism might be involved in the pathogenesis of the metabolic syndrome.     

Particular characteristics of the metabolic syndrome in patients with morbid obesity

BackgroundCriteria for the diagnosis of the metabolic syndrome are currently being reconsidered, as their usefulness is not the same for all phenotypes in relation to the risk of cardiovascular disease.AimWe analyzed the changes in metabolic parameters after a fat overload in different groups of patients.Materials and methodsThe study included 20 healthy persons, 30 metabolic syndrome patients without morbid obesity, 80 metabolic syndrome patients with morbid obesity and 16 patients with morbid obesity without the metabolic syndrome. All the participants received a fat overload of 60 g. Measurements were made before the overload and 3 h afterwards of triglycerides, free fatty acids, insulin and uric acid.ResultsMetabolic syndrome patients with morbid obesity had a lower waist-to-hip ratio, and lower plasma free fatty acid and triglycerides levels at baseline and after the overload than patients without morbid obesity. Plasma uric acid levels rose after the fat overload in the metabolic syndrome patients who had morbid obesity but not in the patients without morbid obesity. A positive relation was found between plasma triglycerides and free fatty acid levels in all the patients but not in the controls after the fat overload. A positive relation was also found between uric acid and insulin levels in the metabolic syndrome patients with morbid obesity.ConclusionsMetabolic syndrome patients with and without morbid obesity presented different metabolic characteristics. This suggests that there are 2 different clinical phenotypes, both grouped under the metabolic syndrome umbrella.     

Characterization of gut microbiota composition in HIV-infected patients with metabolic syndrome

Journal of Physiology and Biochemistry - The presence of metabolic syndrome (MS) per se or its separated components in HIV-infected patients contributes to an accelerated aging and increased...     

The ACE polymorphism is associated with BMI in patients with metabolic syndrome

The angiotensin-converting enzyme (ACE) polymorphism is well known to be associated with cardiovascular diseases. Until now, however, evidence for the role of ACE polymorphism in susceptibility to metabolic syndrome (MS) has not been well studied. Thus, we investigated an association between ACE polymorphisms and Korean patients with MS. DNA samples from 214 MS patients and 193 age-matched non-MS subjects were amplified using the polymerase chain reaction for detection of the ACE insertion/deletion (I/D) and BstUI polymorphisms. Anthropometric and physiological parameters including body mass index (BMI), waist circumference, blood pressure, glucose, triglycerides, total cholesterol and HDL cholesterol were measured. The genotype frequencies of the ACE I/D and BstUI polymorphisms were not significantly different between the non-MS and the MS group. The BB genotype distribution of the BstUI polymorphism in the female subgroup, however, was associated with an increased risk of MS (P = 0.008). When the data were stratified by BMI values, the high BMI groups showed significant differences between the non-MS and the MS groups, compared to the low BMI group, in all genotype frequencies of the ACE I/D and BstUI polymorphisms. The trend remained even when the genotypes of the two polymorphisms were combined. Although no consistent results were obtained on the association between the ACE polymorphism and MS in the populations studied, the ACE polymorphism, at least in Koreans, may be a genetic determinant of BMI in MS patients. Therefore, further studies are required on the association between the ACE polymorphism and MS patients in other racial or ethnic groups.     

Metabolic fluxes and metabolic engineering

Metabolic engineering is the directed improvement of cellular properties through the modification of specific biochemical reactions or the introduction of new ones, with the use of recombinant DNA technology. As such, metabolic engineering emphasizes metabolic pathway integration and relies on metabolic fluxes as determinants of cell physiology and measures of metabolic control. The combination of analytical methods to quantify fluxes and their control with molecular biological techniques to implement genetic modifications is the essence of metabolic engineering. Strategies for metabolic flux determination are reviewed in this paper and it is shown how metabolic fluxes can be used in the systematic elucidation of metabolic control in the framework of reaction grouping and top-down metabolic control analysis.     

Beneficial effect of CLOCK gene polymorphism rs1801260 in combination with low-fat diet on insulin metabolism in the patients with metabolic syndrome

Genetic variation at the Circadian Locomotor Output Cycles Kaput (CLOCK) locus has been associated with lifestyle-related conditions such as obesity, metabolic syndrome (MetS) and cardiovascular diseases. In fact, it has been suggested that the disruption of the circadian system may play a causal role in manifestations of MetS. The aim of this research was to find out whether habitual consumption of a low-fat diet, compared with a Mediterranean diet enriched with olive oil, modulates the associations between common CLOCK single nucleotide polymorphisms (SNPs) (rs1801260, rs3749474 and rs4580704) and lipid and glucose-related traits among MetS patients. Plasma lipid and insulin concentrations, indexes related with insulin resistance (homeostasis model assessment of insulin resistance (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI)) and CLOCK SNPs were determined in 475 MetS subjects participating in the CORDIOPREV clinical trial (NCT00924937). Gene–diet interactions were analyzed after a year of dietary intervention (Mediterranean diet (35% fat, 22% monounsaturated fatty acids (MUFA)) versus low-fat diet (28% fat, 12% MUFA)). We found significant gene–diet interactions between rs1801260 SNP and the dietary pattern for insulin concentrations (p?=?0.009), HOMA-IR (p?=?0.014) and QUICKI (p?=?0.028). Specifically, after 12 months of low-fat intervention, subjects who were homozygous for the major allele (TT) displayed lower plasma insulin concentrations (p?=?0.032), lower insulin resistance (HOMA-IR; p?=?0.027) and higher insulin sensitivity (QUICKI; p?=?0.024) compared with carriers of the minor allele C (TC?+?CC). In contrast, in the Mediterranean intervention group a different trend was observed although no significant differences were found between CLOCK genotypes after 12 months of treatment. Our data support the notion that a chronic consumption of a healthy diet may play a contributing role in triggering glucose metabolism by interacting with the rs1801260 SNP at CLOCK gene locus in MetS patients. Due to the complex nature of gene–environment interactions, dietary adjustment in subjects with the MetS may require a personalized approach.     

Estimation of cell membrane properties and erythrocyte red-ox balance in patients with metabolic syndrome

Metabolic syndrome (MS) is associated with occurrence of the many cardiovascular risk factors such as atherogenic dyslipidemia, visceral fat distribution, arterial hypertension and pro-thrombotic and pro-inflammatory status. In our study the effect of disorders that appear in MS on red-ox balance and erythrocyte cell membrane properties were estimated. The study comprised 50 patients with diagnosed MS and in 25 healthy subjects. Content of thiobarbituric acid reactive substances (TBARS) and catalase, superoxide dismutase and glutathione peroxidase activity were estimated in red blood cells. Moreover, conformation status of membrane proteins, membrane fluidity and osmotic fragility were evaluated. MS was found to manifest: (1) the increase of the concentration of TBARS in erythrocytes with no statistically significant differences in antioxidant enzymes activity, (2) disorders in the structure of erythrocyte cytoskeleton proteins, (3) the increase in membrane lipids fluidity at the depth of 5th and 12th carbon atom of fatty acid hydrocarbon chain and significantly decreased fluidity at the depth of 16th carbon atom, (4) increased erythrocyte osmotic fragility.     

Effect of telmisartan on preexistent cardiac and renal lesions in spontaneously hypertensive mature rats

Fifteen adult male spontaneously hypertensive rats (one year old) (SHR) were separated into three groups (n=5 each) during 15 weeks as follows: initial control group (IC); final control group (FC); and telmisartan group (T) (1.2 mg/kg/day of telmisartan). Serum and urinary creatinine and proteinuria were not different comparing untreated and telmisartan-treated SHRs. FC rats showed a continuous BP increase during the study while T rats reached the 15th week with a significantly low BP. The LV mass index was significantly smaller in the T group than in the FC group, as was the glomerular hypertrophy. The cardiomyocyte nuclei density per area and the cardiomyocyte mean cross-sectional area were smaller in the T group than in both the IC and FC groups. Intramyocardial artery densities (per area and per volume) were greater in the T group than in untreated SHRs, but myocardial fibrosis was reduced. In conclusion, telmisartan monotherapy effects on BP and also on the hypertension target organs, heart and kidney, are favorable. Telmisartan is able to attenuate SHR cardiomyocyte and glomerular hypertrophies, and myocardial reactive fibrosis as well. It also is favorable to the intramyocardial microcirculation.     

Potential utility of combination therapy with nateglinide and telmisartan for metabolic derangements in Zucker Fatty rats.

The metabolic syndrome is strongly associated with insulin resistance and has been recognized as a cluster of risk factors for cardiovascular disease. Insulin resistance and/or impaired early-phase insulin secretion are major determinants of postprandial hyperglycemia. In this study, we investigated the potential utility of combination therapy with telmisartan, an angiotensin II receptor blocker and nateglinide, a rapid-onset/short-duration insulinotropic agent, for the treatment of postprandial hyperglycemia and metabolic derangements in Zucker Fatty (ZF) rats. ZF rats fed twice daily were given vehicle, 50 mg/kg of nateglinide, 5 mg/kg of telmisartan, or both for 6 weeks. Combination therapy with nateglinide and telmisartan for 2 weeks ameliorated postprandial hyperglycemia in ZF rats fed twice daily. Furthermore, 6-week treatment with nateglinide and telmisartan not only decreased fasting plasma insulin, triglycerides, and free fatty acid levels, but also improved the responses of blood glucose to insulin and subsequently reduced the decremental glucose areas under the curve in the ZF rats. Combination therapy also restored the decrease of plasma adiponectin levels in the ZF rats. Monotherapy with nateglinide or telmisartan alone didnot significantly improve these metabolic parameters. These observations demonstrate that combination therapy with nateglinide and telmisartan may improve the metabolic derangements by ameliorating early phase of insulin secretion as well as insulin resistance in ZF rats fed twice daily. Our present findings suggest that the combination therapy with nateglinide and telmisartan could be a promising therapeutic strategy for the treatment of the metabolic syndrome.