In Vivo Stimulation of α- and ß-Adrenoceptors in Mice Differentially Alters Small RNA Content of Circulating Extracellular Vesicles.

When myocardial function is compromised as in heart failure (HF), there is activation of the sympathetic nervous system with elevated circulating catecholamine levels. These catecholamines activate cardiac and extra-cardiac adrenergic receptors (ARs). Interest in secreted extracellular vesicles (EVs) from the heart is growing and in HF, it is not known whether excessive activation of α- or ß-adrenergic receptors (ARs) could induce specific changes in EV content. In this study, we have evaluated, by next generation sequencing, the small RNA content, including micro-RNAs (miRs), of circulating EVs of mice exposed to chronic selective α- or ß- AR stimulation. EVs from mouse blood were purified by differential ultracentrifugation resulting in EVs with an average size of 116.6 ± 4.8 nm that by immunoblotting included protein markers of EVs. We identified the presence of miRs in blood EVs using miR-21-5p and -16-5p real-time PCR as known constituents of blood exosomes that make up a portion of EVs. We next performed next generation sequencing (NGS) of small non-coding RNAs found in blood EVs from mice following 7 days of chronic treatment with isoproterenol (ISO) or phenylephrine (PE) to stimulate α- or ß-ARs, respectively. PE increased the percent of genomic repeat region reads and decreased the percent of miR reads. In miR expression analysis, PE and ISO displayed specific patterns of miR expression that suggests differential pathway regulation. The top 20 KEGG pathways predicted by differential expressed miRs show that PE and ISO share 11 of 20 pathways analyzed and reveal also key differences including three synapse relative pathways induced by ISO relative to PE treatment. Both α-and ß-AR agonists can alter small RNA content of circulating blood EVs/exosomes including differential expression and loading of miRs that indicate regulation of distinct pathways. This study provides novel insight into chronic sympathetic nervous system activation in HF where excessive catecholamines may not only participate in pathological remodeling of the heart but alter other organs due to secretion of EVs with altered miR content.

A Cardiovascular Disease-Linked Gut Microbial Metabolite Acts via Adrenergic Receptors.

Using untargeted metabolomics (n = 1,162 subjects), the plasma metabolite (m/z = 265.1188) phenylacetylglutamine (PAGln) was discovered and then shown in an independent cohort (n = 4,000 subjects) to be associated with cardiovascular disease (CVD) and incident major adverse cardiovascular events (myocardial infarction, stroke, or death). A gut microbiota-derived metabolite, PAGln, was shown to enhance platelet activation-related phenotypes and thrombosis potential in whole blood, isolated platelets, and animal models of arterial injury. Functional and genetic engineering studies with human commensals, coupled with microbial colonization of germ-free mice, showed the microbial porA gene facilitates dietary phenylalanine conversion into phenylacetic acid, with subsequent host generation of PAGln and phenylacetylglycine (PAGly) fostering platelet responsiveness and thrombosis potential. Both gain- and loss-of-function studies employing genetic and pharmacological tools reveal PAGln mediates cellular events through G-protein coupled receptors, including α2A, α2B, and ß2-adrenergic receptors. PAGln thus represents a new CVD-promoting gut microbiota-dependent metabolite that signals via adrenergic receptors.

Oral contraceptives modulate the muscle metaboreflex in healthy young women.

There are known sex differences in blood pressure regulation. The differences are related to ovarian hormones that influence ß-adrenergic receptors and the transduction of muscle sympathetic nerve activity. Oral contraceptives (OC) modulate the ovarian hormonal profile in women and therefore may alter the cardiovascular response. We questioned if OC would alter the absolute pressor response to static exercise and influence the day-to-day variability of the response. Healthy men (n = 11) and women (n = 19) completed a familiarization day and 2 experimental testing days. Women were divided into those taking (W-OC, n = 10) and not taking (W-NC, n = 9) OC. Each experimental testing day involved isometric handgripping exercise, at 30% of maximal force, followed by circulatory occlusion to isolate the metaboreflex. Experimental days in men were 7-14 days apart. The first experimental testing in W-OC occurred 2-7 days after the start of the active phase of their OC. Women not taking OC were tested during the early and late follicular phase of the menstrual cycle as determined by commercial ovulation monitor. The increase in mean arterial pressure (MAP) during exercise was significantly lower in W-NC (95 ± 4 mm Hg) compared with men (114 ± 4 mm Hg) and W-OC (111 ± 3 mm Hg) (P < 0.05), with the differences preserved during circulatory occlusion. The rise in MAP was significantly correlated between the 2 testing days in men (r = 0.72, P < 0.01) and W-OC (r = 0.77, P < 0.05), but not in W-NC (r = 0.17, P = 0.67), indicating greater day-to-day variation in W-NC. In conclusion, OC modulate the exercise pressor response in women and minimize day-to-day variability in the exercise metaboreflex.

ß2 Adrenoceptors are underexpressed in peripheral blood mononuclear cells and associated with a better metabolic profile in central obesity.

Background: Central obesity (CO) is an inflammatory disease. Because immune cells and adipocytes are catecholamines(CA)-producing cells, we studied the expression of adrenoceptors (AR) in peripheral blood mononuclear cells (PBMCs) hypothesizing a distinct adrenergic pattern in inflammatory obesity. Methods: AR expression was assessed in blood donors categorized by waist circumference (WC) (CO: WC≥0.80 m in women and ≥0.94 m in men). Following a pilot study for all AR subtypes, we measured ß2AR expression in fifty-seven individuals and correlated this result with anthropometric, metabolic and inflammatory parameters. A ratio (R) between AR mRNA of CO and non-CO<0.5 was considered under and >2.0 over expression. Results: The pilot study revealed no differences between groups, except for ß2AR mRNA. CO individuals showed underexpression of ß2AR relatively to those without CO (R=0.08; p=0.009). ß2AR expression inversely correlated with triacylglycerol (r=-0.271; p=0.041), very low-density lipoprotein-cholesterol (r=-0.313; p=0.018) and leptin (r=-0.392; p=0.012) and positively with high-density lipoprotein-cholesterol (r=0.310: p=0.045) plasma levels. Multiple logistic regression analysis showed a protective effect of ß2AR expression (≥2x10-6) [odds ratio (OR) 0.177 with respective confidence interval of 95% (95% CI) (0.040- 0.796)] for the occurrence of CO. A higher association was found for women as compared to men (Ξ9:1) [OR 8.972 (95% CI) (1.679-47.949)]. Conclusion: PBMCs ß2AR, underexpressed in centrally obese, are associated with a better metabolic profile and showed a protective role for the development of CO. The discovery of ß2AR as a new molecular marker of obesity subphenotypes in PBMCs might contribute to clarify the adrenergic immunomodulation of inflammatory obesity.

Flow Cytometric Quantification of Peripheral Blood Cell ß-Adrenergic Receptor Density and Urinary Endothelial Cell-Derived Microparticles in Pulmonary Arterial Hypertension.

Pulmonary arterial hypertension (PAH) is a heterogeneous disease characterized by severe angiogenic remodeling of the pulmonary artery wall and right ventricular hypertrophy. Thus, there is an increasing need for novel biomarkers to dissect disease heterogeneity, and predict treatment response. Although ß-adrenergic receptor (ßAR) dysfunction is well documented in left heart disease while endothelial cell-derived microparticles (Ec-MPs) are established biomarkers of angiogenic remodeling, methods for easy large clinical cohort analysis of these biomarkers are currently absent. Here we describe flow cytometric methods for quantification of ßAR density on circulating white blood cells (WBC) and Ec-MPs in urine samples that can be used as potential biomarkers of right heart failure in PAH. Biotinylated ß-blocker alprenolol was synthesized and validated as a ßAR specific probe that was combined with immunophenotyping to quantify ßAR density in circulating WBC subsets. Ec-MPs obtained from urine samples were stained for annexin-V and CD144, and analyzed by a micro flow cytometer. Flow cytometric detection of alprenolol showed that ßAR density was decreased in most WBC subsets in PAH samples compared to healthy controls. Ec-MPs in urine was increased in PAH compared to controls. Furthermore, there was a direct correlation between Ec-MPs and Tricuspid annular plane systolic excursion (TAPSE) in PAH patients. Therefore, flow cytometric quantification of peripheral blood cell ßAR density and urinary Ec-MPs may be useful as potential biomarkers of right ventricular function in PAH.

Altered ß-adrenergic response in mice lacking myotonic dystrophy protein kinase.

The protein kinase product of the gene mutated in myotonic dystrophy 1 (DMPK) is reported to play a role in cardiac pathophysiology. To gain insight into the molecular mechanisms modulated by DMPK, we characterize the impact of DMPK ablation in the context of cardiac ß-adrenergic function. Our data demonstrate that DMPK knockout mice present altered ß-agonist-induced responses and suggest that this is due, at least in part, to a reduced density of ß(1)-adrenergic receptors in cardiac plasma membranes.

Effects of housing and short-term transportation on hormone and lymphocyte receptor concentrations in beef cattle.

The experiment was designed to evaluate the effects of housing system and short-term transportation on the pituitary and adrenal response and on blood progesterone concentrations of beef cattle. Since the use of steroid hormones in farm animals has been banned in the EU (Council Directive 96/22/EC), it seems important to study the possible modifications in serum progesterone concentrations induced by stress in cattle. Thirty-two, 6 months old male Piedmontese beef cattle (16 reared in a littered loose house, Group A, and 16 housed in a littered tying stall barn, Group B) were blood sampled at T1 (6 months old), T2 (12 months old), T3 (18 months old, before transportation to the slaughterhouse) and T4 (after transportation to the slaughterhouse) in order to measure hormonal concentrations and lymphocyte glucocorticoid (GR) and ß-adrenergic (ß-AR) receptor concentrations. Circulating hormone concentrations were measured using commercial radioimmunoassay kits, whereas lymphocyte receptor density was determined through binding assays. In beef cattle housed in tie stall barn a significant increase in serum cortisol concentration was observed at T3, whereas there was no effect of the housing system on blood progesterone concentrations. Short-term transportation caused a significant increase in blood cortisol and catecholamine concentrations in both groups, whereas lymphocyte GR and ß-AR significantly decreased in Group A. Our data confirm the activation of the hypothalamic-pituitary-adrenal axis and the catecholaminergic system in short-term transportation and suggest that the stress-induced increase in circulating progesterone concentrations does not exceed the limit established by pending legislation.

[Clinical efficacy of antihypertensive therapy of pregnant women with arterial hypertension with long acting nifedipine and bisoprolol].

Study aim was assessment of clinical efficacy of mono therapy with nifedipine SR/GITS and combination of nifedipine SR/GITS and bisoprolol as well as investigation of functional state of sympathoadrenal system (SAS) in pregnant women with arterial hypertension. Examination and treatment with nifedipine SR/GITS 30 mg/day and bisoprolol 2,5 - 5 mg/day was carried out in 21 patients with stage II hypertensive disease (HD) during trimester II of pregnancy. Initially all women including 20 practically healthy pregnant women (control group) had elevation of functional activity of SAS what was determined by high values of b-adrenoception of membranes of erythrocytes. In patients with stage II HD this parameter significantly exceeded that of control group. Administration of antihypertensive drugs for 3 weeks promoted significant lowering of all parameters of 24 hour blood pressure monitoring down to optimal level, lessening of pathological types of 24 hour blood pressure profile and lowering of functional activity of SAS.

Cardiac risk stratification in patients with congestive heart failure: a catecholamines-beta-adrenoceptor-cAMP pathway.

OBJECTIVE: To investigate the stratification risk of catecholamines-beta-adrenoceptor (beta-AR)-cAMP pathway for cardiogenic death events in patients with congestive heart failure (CHF). METHODS: A total of 83 identified CHF patients with a baseline and follow-up plasma levels of norepinephrine (NE) and epinephrine (E), lymphocytes beta-AR density (Bmax), and intralymphocyte cAMP content in peripheral blood were followed up. Major cardiogenic death events were registered. RESULTS: The period between the initial entry and the last follow-up measurement were 51 +/- 16 months, the total duration of clinical follow-up after the last measurement were 14 +/- 8 months. During follow-up, 39 patients died of cardiogenic (sudden death 17 patients, worsening heart failure 22 patients). Persistence of high NE, E, and cAMP from baseline to follow-up were confirmed as risk predicting factors of cardiovascular events. Persistence NE above 4.0 nmol/L, E above 3.5 nmol/L, and the intralymphocyte cAMP content above 3.5 pmd x mg(-1) x pro(-1) from baseline to follow-up were significant adverse prognostic predictors. The major cardiogenic death events rates per 100 patients-years were 1.33 and 4.82 in patients with NE below and above 4.0 nmol/L (HR: 2.91; 95% CI: 1.08-7.33; P = 0.015); were 1.42 and 4.36 in the patients with E levels below and above 3.5 nmol/L (HR: 2.64; 95% CI: 1.02-6.41; P = 0.019); were 1.81 and 4.67 in the patients with the intralymphocyte cAMP content below and above 3.5 pmd x mg(-1) x pro(-1) (HR: 2.79; 95% CI: 1.04-6.83; P = 0.017), but difference was not significant between the beta-AR density below and above median. CONCLUSIONS: Persistent increase in circulating catecholamines and intralymphocyte cAMP content may increase the long-term mortality in CHF patients.

Regulation of the catecholamine beta-adrenergic system in ventricular remodeling of hypertension.

Differences in structural remodeling are believed to be influenced by hormonal systems in hypertension. The objective of the present study was to investigate the change in the circulating catecholamine beta-adrenergic system in the left ventricle remodeling process in hypertensives. One hundred and thirty-four men (mean age, 53 years) had essential hypertension and underwent echocardiography before treatment. Normal morphology (n = 26) and concentric remodeling (n = 41) were defined by a relative wall thickness at diastole (RWT) of < 0.44 and > or = 0.44, respectively, and concentric hypertrophy (n = 28) and eccentric hypertrophy (n = 39) by a left ventricular mass index (LVMI) of < 150 g/m(2) and > or = 150 g/m(2), respectively. Forty healthy males were studied as normal controls. Plasma levels of norepinephrine (NE) and epinephrine (E) were measured by high performance liquid chromatography. The density of lymphocyte beta-adrenoceptors (beta-AR) and the content of intralymphocyte cyclic AMP (cAMP) in peripheral blood were measured using (3)H-dihydroalpneol as a ligand and protein binding assay, respectively. The plasma levels of NE and E in the 4 groups of patients with essential hypertension were significantly increased compared with the control group. The density of lymphocyte beta-AR and the content of intralymphocyte cAMP of peripheral blood in the normal morphology, concentric remodeling, and concentric hypertrophy groups were significantly higher than those in the control group, while the values in the eccentric hypertrophy group were significantly lower than those in the control group. Among the 4 groups, the plasma levels of NE and E had increased the most in the normal morphology group, followed in decreasing order by the concentric remodeling, concentric hypertrophy, and eccentric hypertrophy groups; the density of lymphocyte beta-AR and the content of intralymphocyte cAMP of peripheral blood in the normal morphology, concentric remodeling, and concentric hypertrophy groups increased while they decreased in the eccentric hypertrophy group in patients with essential hypertension. The catecholamine beta-adrenergic system appears to be related to left ventricular remodeling of hypertension. In this process, catecholamines increased continually. The density of beta-AR and the content of cAMP in peripheral lymphocytes increased at first and then decreased.

Nitric oxide generation mediated by beta-adrenoceptors is impaired in platelets from patients with Type 2 diabetes mellitus.

AIMS/HYPOTHESIS: Type 2 diabetic patients have been shown to have reduced basal platelet nitric oxide synthase activity, which is a possible contributor to the vascular complications seen in the disease. We investigated platelet nitric oxide generation stimulated by beta-adrenoceptors and adenylyl cyclase in Type 2 diabetic patients and control subjects. METHODS: Platelets isolated from blood taken from nine Type 2 diabetic patients and nine healthy control subjects of similar age were treated with isoproterenol 1 micro mol/l, forskolin 1 micro mol/l or vehicle. Platelet nitric oxide synthase activity was measured by L-[(3)H]-arginine to L-[(3)H]-citrulline conversion, cyclic GMP content by radioimmunoassay, and nitric oxide synthase type 3 expression by western blotting. RESULTS: Basal platelet nitric oxide synthase activity was lower in diabetic patients than in control subjects (0.01+/-0.02 pmol L-citrulline/10(8) platelets, compared with 0.12+/-0.05; p<0.05), although no corresponding difference was seen in basal platelet cyclic GMP (0.61+/-0.39 and 0.13+/-0.22 pmol cyclic GMP/10(8) platelets respectively; p=0.37). In control subjects isoproterenol 1 micro mol/l and forskolin 1 micro mol/l increased platelet nitric oxide synthase activity (to 0.27+/-0.08 and 0.27+/-0.07 pmol L-citrulline/10(8) platelets respectively; p<0.05 for each in comparison with basal) and cyclic GMP (to 1.84+/-0.41 and 1.86+/-0.48; p<0.05 for each in comparison with basal). This effect was not achieved in diabetic patients. Isoproterenol- and forskolin-stimulated cyclic GMP correlated inversely with plasma glucose and HbA(1c). Platelet nitric oxide synthase type 3 expression was not different in control and diabetic subjects and was not changed by acute exposure of platelets to isoproterenol. CONCLUSIONS/INTERPRETATION: Nitric oxide generation stimulated by beta-adrenoceptors and adenylyl cyclase is impaired in platelets of people with Type 2 diabetes mellitus, with no corresponding change in nitric oxide synthase type 3 expression. It is possible that this impairment contributes to the thrombotic and atherosclerotic complications of Type 2 diabetes.

Effects of catecholamine-beta-adrenoceptor-cAMP system on severe patients with heart failure.

OBJECTIVE: To investigate the association between catecholamine-beta-adrenoceptor (beta-AR)-adenosine 3', 5'-monophosphate (cAMP) system and long-term prognosis in patients with chronic heart failure (CHF). METHODS: The study population comprised 73 patients with CHF (EF: 23% +/- 10%) with a mean follow-up of 3.8 +/- 1.9 years. Plasma levels of norepinephrine (NE) were measured using high performance lipid chromatography, beta-adrenergic receptor density (Bmax) and the content of cAMP in peripheral lymphocytes were calculated using 3H-dihydroalpneolo as ligand and competitive immunoassay, respectively. Deaths due to cardiovascular events within the follow-up period were registered. RESULTS: The total mortality was 64.7%, 57.4% of which was for cardiogenic (worsening heart failure: 32.4%; sudden death: 25.0%). In the cardiogenic death group, plasma levels of NE and epinephrine (E) (3.74 nmol/L +/- 0.09 nmol/L and 3.17 nmol/L +/- 1.0 nmol/L) and the contents of peripheral lymphocyte cAMP (3.64 pmol/mg protein +/- 1.4 pmol/mg protein) were significantly increased as compared with the survival group (2.68 nmol/L +/- 0.07 nmol/L, 2.41 nmol/L +/- 0.24 nmol/L and 2.73 pmol/mg protein +/- 0.9 pmol/mg protein, respectively, all P < 0.01). In the sudden death group, plasma levels of NE and E (5.01 nmol/L +/- 0.06 nmol/L and 4.13 nmol/L +/- 0.08 nmol/L) were significantly increased as compared with the worsening heart failure group (2.49 nmol/L +/- 0.07 nmol/L and 2.33 nmol/L +/- 0.8 nmol/L, all P < 0.001) and to the survival group (2.68 nmol/L +/- 0.07 nmol/L and 2.41 nmol/L +/- 0.14 nmol/L, all P < 0.01). The incidences of sudden death were 0%, 75%, and 100% (chi(2) = 16.018, P < 0.01) in patients with plasma NE < 2.5 nmol/L, NE 2.5 nmol/L - 4.5 nmol/L, and NE > 4.5 nmol/L, respectively. In the worsening heart failure group, the content of peripheral lymphocyte cAMP (4.46 pmol/mg protein +/- 0.18 pmol/mg protein) was significantly increased compared with the sudden death group (2.39 pmol/mg protein +/- 0.9 pmol/mg protein, P < 0.001) and to the survival group (2.73 pmol/mg protein +/- 1.1 pmol/mg protein, P < 0.001). The worsening heart failure death occurences were 5.0%, 72.2%, and 100% (chi(2) = 14.26, P < 0.01) in patients with a content of peripheral lymphocyte cAMP < 2.5 nmol/L, cAMP 2.5 nmol/L - 4.5 nmol/L, and cAMP > 4.5 nmol/L, respectively. Bmax in peripheral lymphocyte was not significantly different (P > 0.05) among the sudden death, worsening heart failure, and survival groups in CHF patients. CONCLUSIONS: Plasma levels of catecholamine increase significantly, and Bmax and the contents of cAMP in peripheral lymphocytes decrease significantly in patients with CHF. High plasma catecholamine levels may be associated with sudden death, and high intralymphocyte cAMP content may be associated with worsening heart failure in CHF patients.

High plasma buffering and the absence of a red blood cell beta-NHE response in brown bullhead (Ameiurus nebulosus).

The high non-bicarbonate buffer capacity of brown bullhead (Ameiurus nebulosus) plasma was postulated to function as an alternative mechanism for the protection of red blood cell (RBC) intracellular pH (pHi) in the absence or attenuation of a RBC adrenergic response. The requirement for protecting RBC pHi arises from the presence of a Root effect haemoglobin in bullhead. In support of this hypothesis, bullhead RBCs incubated in vitro with isoproterenol (10(-8)-10(-5) mol l(-1)) or forskolin (10(-4) mol l(-1)) exhibited significant cyclic AMP accumulation, but failed to exhibit cell swelling or significant Na(+) or Cl(-) accumulation; plasma pH (pHe) was also unaffected. Similarly, no significant effect on RBC water content, Na(+) or Cl(-) concentration, or pHe was detected in bullhead blood incubated with 8-bromo cyclic AMP (10(-4)-10(-2) mol l(-1)) in vitro. These results suggest that while bullhead RBCs possess a beta-adrenoreceptor linked to cyclic AMP formation, stimulation of this adrenergic receptor does not result in measurable activation of a Na(+)/H(+) exchanger.

Association of Trp64Arg polymorphism of the beta3-adrenergic receptor gene and no association of Gln223Arg polymorphism of the leptin receptor gene in Japanese schoolchildren with obesity.

OBJECTIVE: To investigate whether Trp64Arg polymorphism of the beta3-adrenergic receptor (beta3-AR) gene and Gln223Arg polymorphism of the leptin receptor (Ob-R) gene are associated with obesity in Japanese schoolchildren. DESIGN: Population study of participants from a rural town located within 50 km northeast of Tokyo based on school medical examinations. SUBJECTS: 553 Japanese schoolchildren (291 boys and 262 girls) who were 9-15 y old with a mean age of 11.9 +/- 1.8 y. MEASUREMENTS: DNA was extracted from whole blood and genotyped by PCR-RFLP. Height, weight and blood pressure were measured in school medical examinations. Total cholesterol, triglyceride and HDL-cholesterol concentrations were measured by an autoanalyzer. Obesity index, body mass index (BMI) and LDL-cholesterol concentration were calculated by the respective formulae. RESULTS: In Trp64Arg polymorphism of the beta3-AR gene, the number of obese subjects with Trp/Arg or Arg/Arg genotypes was significantly higher than that of the non-obese subjects (chi2=5.79, P=0.02). The obesity index of subjects with the Arg/Arg or Arg/Trp genotype was significantly higher than that of those with the Trp/Trp genotype (8.2 +/- 18.7% vs 4.5 +/- 15.8%, P=0.04). Moreover, after adjustments for age and gender, BMI of subjects with the Trp/Arg or Arg/Arg genotype was significantly higher than that of those with the Trp/Trp genotype (19.4 +/- 3.6 kg/m2 vs 18.9 +/- 3.2 kg/m2, P= 0.02). However, no significant differences were observed in the clinical characteristics among the genotype groups of the Ob-R gene. CONCLUSIONS: Trp64Arg polymorphism of the beta3-AR gene appears to be a genetic risk factor for obesity in Japanese children, but Gln223Arg polymorphism of the Ob-R gene does not appear to be associated with obesity.

Association of sets of alleles of genes encoding beta3-adrenoreceptor, uncoupling protein 1 and lipoprotein lipase with increased risk of metabolic complications in obesity.

OBJECTIVE: To investigate the relationship between the polymorphisms of the beta3-AR (Trp64Arg), UCP1 (A-->G) and LPL (HindIII and PvuII) loci and the metabolic complications associated with obesity in a Turkish population. SUBJECTS: 271 unrelated individuals of Turkish origin including obese (body mass index, BMI>30 kg¿m2) and lean (BMI< or =25 kg¿m2) subjects. MEASUREMENTS: Anthropometric (weight, height and blood pressure) and metabolic measurements (plasma levels of glucose, cholesterol and triglycerides), and determination of beta3-AR, UCP1 and LPL genotypes by polymerase chain reaction followed by enzymatic digestion. RESULTS: The distributions of genotypes for each candidate gene (beta3-AR, UCP1 and LPL) were similar between the obese and the lean subjects. The Arg64 allele of the beta3-AR gene was absent from massively obese men. GG carriers of the A-->G variant of the UCP1 gene showed BMI-associated increases of cholesterol levels which were more marked than both AA (P=0.027) and AG (P=0.039) carriers. Obese P+ carriers of the LPL PvuII variant had significantly higher levels of glucose than non-carriers (P=0.011), whereas obese P+P+ carriers did not have significantly different levels of triglycerides than non-carriers (P=0.087). Moreover, carriers of both alleles (G&P+) had higher levels of glucose than non-carriers (P=0.048), but did not have significantly different levels of triglycerides than non-carriers (P=0.125). However, the BMI-associated increase of triglycerides of P+&G carriers was significantly more marked than that of P+ carriers (P=0.0085). CONCLUSION: Our data support the idea that alleles of specific genes (UCP1, LPL and beta3-AR) might play a role in the development of certain metabolic complications of obesity and might have additive effects when combined with each other (as in the case of UCP1 and LPL). International Journal of Obesity (2000)24, 93-100

[The relationships of mononuclear leukocyte beta-adrenergic receptors to aerobic capacity and exercise-induced asthma in asthmatic children].

beta-adrenaline receptors exist on peripheral mononuclear leukocytes as well as in lung tissue. We assessed the relationships of plasma catecholamine release by exercise to aerobic capacity and to exercise-induced asthma (EIA) in asthmatic children (Study 1). We then measured mononuclear leukocyte beta-adrenergic receptor densities at rest and assessed the relationships of the number of receptors to aerobic capacity, EIA, and bronchial responsiveness to acetylcholine (Study 2). Study 1: Eleven children (9 males, 2 females; 11-16 years old) with bronchial asthma participated in this study. The subjects underwent an incremental aerobic exercise test on a cycle ergometer to determine their aerobic capacity at the lactic threshold (LT) and VO2max. Each subject underwent an EIA test of which the intensity was 175% of LT, and plasma catecholamine concentrations were measured before and after exercise. A significant negative relationship was found between the degree of EIA and % change of plasma adrenaline concentrations to rest level (p < 0.05), and a significant positive relationship was found between VO2 max/wt and % change of plasma adrenaline concentrations (p < 0.05). Study 2: Twelve asthmatic children (10 males, 2 females; 11-16 years old) participated in this study. Aerobic capacity, and degree of EIA were also measured in each subject by the same method as that used in Study. 1. The number of mononuclear leukocyte beta-adrenergic receptors at rest was determined by (-) [125I]-iodocyanopindolol binding in each subject. A significant negative relationship was found between the number of adrenergic receptors and Max. % fall in FEV1.0 (p < 0.01), and a significant positive relationship was found between the number of adrenergic receptors and VO2max/kg (p < 0.001). These results suggested that a reduced adrenaline production and a reduced number of beta-receptors contributed to the pathogenesis of EIA.

[Expression of beta 2-adrenoceptor on peripheral lymphocyte and the level of plasma cAMP in patients with pregnancy induced hypertension].

OBJECTIVE: To evaluate the alteration of beta 2-adrenoceptor-cAMP system in patients with pregnancy-induced hypertension (PIH). METHODS: The Bmax of beta 2-adrenoceptor on the lymphocyte was examined by radioligand binding technique. The level of plasma cAMP was observed by radio competitive protein binding assay. RESULTS: The Bmax of beta 2-adrenoceptor (259 fmol/10(6) cell +/- 22 fmol/10(6) cell) on the lymphocytes was significantly higher in PIH group than in control group (247 fmol/10(6) cell +/- 23 fmol/10(6) cell). There was no significant difference between the PIH group and the controls. The content of plasma cAMP (2.94 nmol/40 microliters +/- 0.91 nmol/40 microliters) was significantly higher in PIH group than in control group (0.19 nmol/40 microliters +/- 0.05 nmol/40 microliters). CONCLUSION: The mechanism of PIH may be related with the activity of beta 2-adrenoceptor-cAMP system.

Effects of diltiazem on down-regulation of lymphocyte beta-adrenoceptors in patients with chronic congestive heart failure.

AIM: To determine whether diltiazem could reverse down-regulation of lymphocyte beta-adrenoceptor (beta-AR) in patients with chronic congestive heart failure (CHF). METHODS: Before and after the treatment with diltiazem in CHF patients, lymphocyte beta-AR density was measured with [3H]dihydroalprenolol radioligand binding assay, levels of free cytosolic calcium ([Ca2+]i) in platelets were estimated with fluorescent indicator Fura 2-AM, plasma norepinephrine (NE) levels were measured with 125I-radioimmunoassay. RESULTS: Lymphocyte beta-AR density was lower and [Ca2+]i in platelets was significantly higher in CHF patients than those in control. Plasma NE levels were higher in CHF patients than those in control. Diltiazem therapy reduced [Ca2+]i in platelets and increased lymphocyte beta-AR density in CHF patients without significant change of plasma NE concentration. CONCLUSIONS: Diltiazem partly reversed down-regulation of lymphocyte beta-AR density in CHF patients, and this effect was not related to the level of plasma NE, and might be attributed to intracellular [Ca2+]i decrease.