α-Hydroxybutyric Acid Is a Selective Metabolite Biomarker of Impaired Glucose Tolerance.

Objective: Plasma metabolites that distinguish isolated impaired glucose tolerance (iIGT) from isolated impaired fasting glucose (iIFG) may be useful biomarkers to predict IGT, a high-risk state for the development of type 2 diabetes.

Research Design And Methods: Targeted metabolomics with 23 metabolites previously associated with dysglycemia was performed with fasting plasma samples from subjects without diabetes at time 0 of an oral glucose tolerance test (OGTT) in two observational cohorts: RISC (Relationship Between Insulin Sensitivity and Cardiovascular Disease) and DMVhi (Diabetes Mellitus and Vascular Health Initiative). Odds ratios (ORs) for a one-SD change in the metabolite level were calculated using multiple logistic regression models controlling for age, sex, and BMI to test for associations with iIGT or iIFG versus normal.

Persistent increases in Ca(2+) influx through Cav1.2 shortens action potential and causes Ca(2+) overload-induced afterdepolarizations and arrhythmias.

Persistent elevation of Ca(2+) influx due to prolongation of the action potential (AP), chronic activation of the β-adrenergic system and molecular remodeling occurs in stressed and diseased hearts. Increases in Ca(2+) influx are usually linked to prolonged myocyte action potentials and arrhythmias. However, the contribution of chronic enhancement of Cav1.

Untargeted metabolomic analysis for the clinical screening of inborn errors of metabolism.

Global metabolic profiling currently achievable by untargeted mass spectrometry-based metabolomic platforms has great potential to advance our understanding of human disease states, including potential utility in the detection of novel and known inborn errors of metabolism (IEMs). There are few studies of the technical reproducibility, data analysis methods, and overall diagnostic capabilities when this technology is applied to clinical specimens for the diagnosis of IEMs. We explored the clinical utility of a metabolomic workflow capable of routinely generating semi-quantitative z-score values for ~900 unique compounds, including ~500 named human analytes, in a single analysis of human plasma.

A novel test for IGT utilizing metabolite markers of glucose tolerance.

The oral glucose tolerance test (OGTT) is the only method to diagnose patients having impaired glucose tolerance (IGT), but its use has diminished considerably in recent years. Metabolomic profiling studies have identified a number of metabolites whose fasting levels are associated with dysglycemia and type 2 diabetes. These metabolites may serve as the basis of an alternative test for IGT.

Understanding the apothecaries within: the necessity of a systematic approach for defining the chemical output of the human microbiome.

The human microbiome harbors a massive diversity of microbes that effectively form an "organ" that strongly influences metabolism and immune function and hence, human health. Although the growing interest in the microbiome has chiefly arisen due to its impact on human physiology, the probable rules of operation are embedded in the roots of microbiology where chemical communication (i.e.

Exploiting functional domains of GRK2/3 to alter the competitive balance of pro- and anticontractile signaling in airway smooth muscle.

To clarify the potential utility of targeting GRK2/3-mediated desensitization as a means of manipulating airway smooth muscle (ASM) contractile state, we assessed the specificity of GRK2/3 regulation of procontractile and relaxant G-protein-coupled receptors in ASM. Functional domains of GRK2/3 were stably expressed, or siRNA-mediated GRK2/3 knockdown was performed, in human ASM cultures, and agonist-induced signaling was assessed. Regulation of contraction of murine tracheal rings expressing GRK2 C terminus was also assessed.

Metabolomics as a key integrator for "omic" advancement of personalized medicine and future therapies.

Investigation into biological complexity, whether for a better understanding of disease or drug process, is a monumental task plaguing investigators. The lure of "omic" technologies for circumventing much of these challenges has led to widespread efforts and adoption. It is becoming clearer that a single "omic" approach (e.

Stabilization of the resistive wall mode by a rotating solid conductor.

Stabilization of the resistive wall mode (RWM) by high-speed differentially rotating conducting walls is demonstrated in the laboratory. To observe stabilization intrinsic azimuthal plasma rotation must be braked with error fields. Above a critical error field the RWM frequency discontinuously slows (locks) and fast growth subsequently occurs.

S100A1 genetically targeted therapy reverses dysfunction of human failing cardiomyocytes.

Objectives: This study investigated the hypothesis whether S100A1 gene therapy can improve pathological key features in human failing ventricular cardiomyocytes (HFCMs).

Background: Depletion of the Ca²⁺-sensor protein S100A1 drives deterioration of cardiac performance toward heart failure (HF) in experimental animal models. Targeted repair of this molecular defect by cardiac-specific S100A1 gene therapy rescued cardiac performance, raising the immanent question of its effects in human failing myocardium.

Ex vivo thermoacoustic imaging over large fields of view with 108 MHz irradiation.

Thermoacoustic signals are generated over a large field of view by 900 ns TE10 pulses with 108 MHz carrier frequency. Test specimens selectively absorb the TE10 pulse energy producing rapid thermal expansions that generate ultrasonic pulses. 108 MHz irradiation provides excellent depth penetration in soft tissue, allowing blood and physiologic saline to generate strong signals.

Calcium influx through Cav1.2 is a proximal signal for pathological cardiomyocyte hypertrophy.

Pathological cardiac hypertrophy (PCH) is associated with the development of arrhythmia and congestive heart failure. While calcium (Ca(2+)) is implicated in hypertrophic signaling pathways, the specific role of Ca(2+) influx through the L-type Ca(2+) channel (I(Ca-L)) has been controversial and is the topic of this study. To determine if and how sustained increases in I(Ca-L) induce PCH, transgenic mouse models with low (LE) and high (HE) expression levels of the β2a subunit of Ca(2+) channels (β2a) and in cultured adult feline (AF) and neonatal rat (NR) ventricular myocytes (VMs) infected with an adenovirus containing a β2a-GFP were used.

The inotropic peptide βARKct improves βAR responsiveness in normal and failing cardiomyocytes through G(βγ)-mediated L-type calcium current disinhibition.

Rationale: The G(βγ)-sequestering peptide β-adrenergic receptor kinase (βARK)ct derived from the G-protein-coupled receptor kinase (GRK)2 carboxyl terminus has emerged as a promising target for gene-based heart failure therapy. Enhanced downstream cAMP signaling has been proposed as the underlying mechanism for increased β-adrenergic receptor (βAR) responsiveness. However, molecular targets mediating improved cardiac contractile performance by βARKct and its impact on G(βγ)-mediated signaling have yet to be fully elucidated.

Impaired neoangiogenesis in β₂-adrenoceptor gene-deficient mice: restoration by intravascular human β₂-adrenoceptor gene transfer and role of NFκB and CREB transcription factors.

Background And Purpose: There is much evidence supporting the role of β₂-adrenoceptors (β₂AR) in angiogenesis but the mechanisms underlying their effects have not been elucidated. Hence, we studied post-ischaemic angiogenesis in the hindlimb (HL) of β₂AR knock-out mice (β₂AR-/-) in vivo and explored possible molecular mechanisms in vitro.

Experimental Approach: Femoral artery resection (FAR) was performed in wild-type and β₂AR-/- mice and adaptive responses to chronic HL ischaemia were explored; blood flow was measured by ultrasound and perfusion of dyed beads, bone rarefaction, muscle fibrosis and skin thickness were evaluated by immunoflourescence and morphometric analysis.

Level of G protein-coupled receptor kinase-2 determines myocardial ischemia/reperfusion injury via pro- and anti-apoptotic mechanisms.

Rationale: Activation of prosurvival kinases and subsequent nitric oxide (NO) production by certain G protein-coupled receptors (GPCRs) protects myocardium in ischemia/reperfusion injury (I/R) models. GPCR signaling pathways are regulated by GPCR kinases (GRKs), and GRK2 has been shown to be a critical molecule in normal and pathological cardiac function.

Objective: A loss of cardiac GRK2 activity is known to arrest progression of heart failure (HF), at least in part by normalization of cardiac β-adrenergic receptor (βAR) signaling.

Regulation of GPCR signaling in hypertension.

Hypertension represents a complex, multifactorial disease and contributes to the major causes of morbidity and mortality in industrialized countries: ischemic and hypertensive heart disease, stroke, peripheral atherosclerosis and renal failure. Current pharmacological therapy of essential hypertension focuses on the regulation of vascular resistance by inhibition of hormones such as catecholamines and angiotensin II, blocking them from receptor activation. Interaction of G-protein coupled receptor kinases (GRKs) and regulator of G-protein signaling (RGS) proteins with activated G-protein coupled receptors (GPCRs) effect the phosphorylation state of the receptor leading to desensitization and can profoundly impair signaling.

[Activation of sterol regulatory element binding protein and its involvement in endothelial cell migration].

Objective: To study the activation of sterol regulatory element binding protein (SREBP) and its critical role in endothelial cell migration.

Methods: Bovine aortic endothelial cells (ECs) were cultured. The expression of SREBP and Cdc42 were determined by Western blot and quantitative real-time PCR.

G protein-coupled receptor kinase 2 expression and activity are associated with blood pressure in black Americans.

Hypertension occurs with higher prevalence and morbidity in black Americans compared with other groups. Alterations in the signal transduction pathways of 7-transmembrane spanning receptors are found in hypertensive patients. G protein-coupled receptor kinases (GRKs) play an important role in regulating this receptor signaling.

Negative regulation of VEGF signaling in human coronary artery endothelial cells by G protein-coupled receptor kinase 5.

G protein-coupled receptor kinase 5 (GRK5) is present in endothelial cells (ECs) and has the potential to regulate EC function through seven transmembrane-spanning receptor (7TMR) signaling. Recently, it has been appreciated that GRKs can affect receptor tyrosine kinases (RTKs). VEGF, an RTK, is one of the most potent mediators for EC function and angiogenesis; therefore, we determined the role GRK5 plays in VEGF signaling in human coronary artery ECs (HCAECs).

Inhibition of angiotensin II Gq signaling augments beta-adrenergic receptor mediated effects in a renal artery stenosis model of high blood pressure.

Chronic ventricular pressure overload states, such as hypertension, and elevated levels of neurohormones (norepinephrine, angiotensin II, endothelin-1) initiate cardiac hypertrophy and dysfunction and share the property of being able to bind to Gq-coupled 7-transmembrane receptors. The goal of the current study was to determine the role of endogenous cardiac myocyte Gq signaling and its role in cardiac hypertrophy and dysfunction during high blood pressure (BP). We induced renal artery stenosis for 8 weeks in control mice and mice expressing a peptide inhibitor of Gq signaling (GqI) using a 2 kidney, 1 clip renal artery stenosis model.

Inhibition of vascular smooth muscle G protein-coupled receptor kinase 2 enhances alpha1D-adrenergic receptor constriction.

G protein-coupled receptor kinase 2 (GRK2) is a serine/theorinine kinase that phosphorylates and desensitizes agonist-bound G protein-coupled receptors. GRK2 is increased in expression and activity in lymphocytes and vascular smooth muscle (VSM) in human hypertension and animal models of the disease. Inhibition of GRK2 using the carboxyl-terminal portion of the protein (GRK2ct) has been an effective tool to restore compromised beta-adrenergic receptor (AR) function in heart failure and improve outcome.

Uncovering G protein-coupled receptor kinase-5 as a histone deacetylase kinase in the nucleus of cardiomyocytes.

G protein-coupled receptor (GPCR) kinases (GRKs) are critical regulators of cellular signaling and function. In cardiomyocytes, GRK2 and GRK5 are two GRKs important for myocardial regulation, and both have been shown to be up-regulated in the dysfunctional heart. We report that increased levels and activity of GRK5 in failing myocardium may have unique significance due to its nuclear localization, a property not shared by GRK2.

G protein-coupled receptor kinase 2 ablation in cardiac myocytes before or after myocardial infarction prevents heart failure.

Myocardial G protein-coupled receptor kinase (GRK)2 is a critical regulator of cardiac beta-adrenergic receptor (betaAR) signaling and cardiac function. Its upregulation in heart failure may further depress cardiac function and contribute to mortality in this syndrome. Preventing GRK2 translocation to activated betaAR with a GRK2-derived peptide that binds G(beta)gamma (betaARKct) has benefited some models of heart failure, but the precise mechanism is uncertain, because GRK2 is still present and betaARKct has other potential effects.

GPCR signalling in hypertension: role of GRKs.

Hypertension is a prevalent condition in the developed world and disease severity is directly correlated with additional cardiovascular complications. It is estimated that 30% of the adult population in the United States has hypertension, which is classified as a systolic blood pressure > or =140 mmHg and/or a diastolic blood pressure > or =90 mmHg. A prolonged increase in afterload ultimately leads to congestive heart failure in the majority of cases.