Hypertensive left ventricular hypertrophy: relation to beta-adrenergic receptor kinase-1 (betaARK1) in peripheral lymphocytes

Different effects of prolonged β-adrenergic stimulation on heart and cerebral artery

The aim of this review was to understand the effects of β-adrenergic stimulation on oxidative stress, structural remodeling, and functional alterations in the heart and cerebral artery. Diverse stimuli activate the sympathetic nervous system, leading to increased levels of catecholamines. Long-term overstimulation of the β-adrenergic receptor (βAR) in response to catecholamines causes cardiovascular diseases, including cardiac hypertrophy, stroke, coronary artery disease, and heart failure. Although catecholamines have identical sites of action in the heart and cerebral artery, the structural and functional modifications differentially activate intracellular signaling cascades. βAR-stimulation can increase oxidative stress in the heart and cerebral artery, but has also been shown to induce different cytoskeletal and functional modifications by modulating various components of the βAR signal transduction pathways. Stimulation of βAR leads to cardiac dysfunction due to an overload of intracellular Ca²⁺ in cardiomyocytes. However, this stimulation induces vascular dysfunction through disruption of actin cytoskeleton in vascular smooth muscle cells. Many studies have shown that excessive concentrations of catecholamines during stressful conditions can produce coronary spasms or arrhythmias by inducing Ca²⁺-handling abnormalities and impairing energy production in mitochondria, In this article, we highlight the different fates caused by excessive oxidative stress and disruptions in the cytoskeletal proteome network in the heart and the cerebral artery in responsed to prolonged βAR-stimulation.

Leukocyte ß-adrenergic receptor sensitivity and depression severity in patients with heart failure

OBJECTIVES

Clinical outcomes are worse for patients with heart failure (HF) and elevated depression symptoms. Depression-related sympathoimmune dysregulation may be one mechanism leading to poorer HF prognosis. Sympathetically mediated adrenergic activity is known to regulate immune activity via β-adrenergic receptors (β-ARs). However, studies show conflicting relationships between leukocyte β-AR sensitivity and depression symptoms. The aim of this study was to determine in patients with HF the relationship of leukocyte β-AR sensitivity with two diverse measures of depression, self-report questionnaire versus clinical diagnostic interview.

METHODS

Patients with HF (N = 73, mean [standard deviation] age = 56.3 [13.0]) completed the Beck Depression Inventory-1A and a modified Structured Clinical Interview for the DSM-IV. Leukocyte β-AR sensitivity was determined from isoproterenol-stimulated cyclic adenosine monophosphate levels; plasma norepinephrine and epinephrine were also assessed.

RESULTS

Patients with major depression determined by Structured Clinical Interview for the DSM-IV had significantly higher β-AR sensitivity than did nondepressed patients (F(6,72) = 9.27, p = .003, η = 0.12). The Beck Depression Inventory-1A revealed a more complex relationship. Minimal, mild, and moderate-to-severe depression symptom groups had significant differences in β-AR sensitivity (F(7,72) = 7.03, p = .002, η = 0.18); mild symptoms were associated with reduced β-AR sensitivity and moderate-to-severe symptoms with higher β-AR sensitivity compared with patients with minimal depressive symptoms.

CONCLUSIONS

Clinical depression was associated with elevated β-AR sensitivity in patients with HF. By deconstructing depression measurements, a greater depth of information may be garnered to potentially reveal subtypes of depression symptoms and their relation to β-AR sensitivity.

Depression as a potential modulator of Beta-adrenergic-associated leukocyte mobilization in heart failure patients

OBJECTIVES

the aim of this study was to determine whether depressive symptoms are related to alterations in the sensitivity of peripheral blood mononuclear cells to β-adrenergic agonists in patients with heart failure (HF) by measuring in vitro chemotaxis (CTX) to isoproterenol at rest and after acute exercise in patients with HF and controls.

BACKGROUND

clinical outcomes are worse for patients with HF presenting with symptoms of depression. Sympathetically modulated immune dysregulation associated with depression may be one mechanism leading to worse prognosis.

METHODS

seventy-seven patients with HF and 44 controls (mean age 56.4 ± 1.3 years) completed the Beck Depression Inventory and a 15-min mild-graded exercise task on a stationary bicycle. Exercise intensity was kept relative to fitness levels for all participants by gradually increasing resistance to reach a Borg scale subjective rating of 12 to 13, "somewhat hard." Plasma norepinephrine and epinephrine levels were measured before and after exercise. Chemotaxis to isoproterenol was determined by measuring in vitro peripheral blood mononuclear cell migration through a modified Boyden chamber.

RESULTS

In patients with HF, depressive symptom severity was associated with greater CTX after exercise (p = 0.001). Higher resting norepinephrine in patients with HF was also associated with increased CTX to exercise (p = 0.03).

CONCLUSIONS

patients with HF with higher depressive symptoms and norepinephrine exhibited increased peripheral blood mononuclear cell CTX to isoproterenol to mild exercise, suggesting greater β-adrenergic sensitivity. Increased immune migration in patients with HF who have elevated depressive symptoms could be associated with cardiac remodeling and HF disease progression.

Mice lacking the Cβ subunit of PKA are resistant to angiotensin II-induced cardiac hypertrophy and dysfunction

BACKGROUND

PKA is a ubiquitous, multi-subunit cellular kinase that regulates a number of different physiological responses in response to cAMP, including metabolism, cell division, and cardiac function. Numerous studies have implicated altered PKA signaling in cardiac dysfunction. Recently, it has been shown that mice lacking the catalytic β subunit of PKA (PKA Cβ) are protected from age-related problems such as weight gain and enlarged livers, and we hypothesized that these mice might also be resistant to cardiomyopathy.

FINDINGS

Angiotensin II (ang II) induced hypertension in both PKA Cβ null mice and their WT littermates. However, PKA Cβ null mice were resistant to a number of ang II-induced, cardiopathological effects observed in the WT mice, including hypertrophy, decreased diastolic performance, and enlarged left atria.

CONCLUSION

The Cβ subunit of PKA plays an important role in angiotensin-induced cardiac dysfunction. The Cβ null mouse highlights the potential of the PKA Cβ subunit as a pharmaceutical target for hypertrophic cardiac disease.

G-protein-coupled receptor kinases in cardiovascular conditions: focus on G-protein-coupled receptor kinase 2, a gain in translational medicine

With increasing knowledge of the regulatory mechanisms of G-protein-coupled receptor signaling in heart physiology, many studies have focused on the role of this system in cardiovascular disease. In recent years, scientists have moved their attention from the receptors to their regulatory proteins: the G-protein-coupled receptor kinases. This class of protein is indispensable for terminating signaling of G-protein-coupled receptors through receptor desensitization and downregulation. This article attempts to assemble the currently available information regarding G-protein-coupled receptor kinases and their role in cardiovascular disease and, in particular, the potential employment of G-protein-coupled receptor kinase 2 as biomarker of cardiac dysfunction.

Blood pressure and heart rate QTL in mice of the B6/D2 lineage: sex differences and environmental influences

A quantitative trait locus (QTL) approach was used to define the genetic architecture underlying variation in systolic blood pressure (SBP) and heart rate (HR), measured indirectly on seven occasions by the tail cuff procedure. The tests were conducted in 395 F(2) adult mice (197 males, 198 females) derived from a cross of the C57BL/6J (B6) and DBA/2J (D2) strains and in 22 BXD recombinant-inbred (RI) strains. Interval mapping of F(2) data for the first 5 days of measurement nominated one statistically significant and one suggestive QTL for SBP on chromosomes (Chr) 4 and 14, respectively, and two statistically significant QTL for HR on Chr 1 (which was specific to female mice) and Chr 5. New suggestive QTL emerged for SBP on Chr 3 (female-specific) and 8 and for HR on Chr 11 for measurements recorded several weeks after mice had undergone stressful blood sampling procedures. The two statistically significant HR QTL were confirmed by analyses of BXD RI strain means. Male and female F(2) mice did not differ in SBP or HR but RI strain analyses showed pronounced strain-by-sex interactions and a negative genetic correlation between the two measures in both sexes. Evidence for a role for mitochondrial DNA was found for both HR and SBP. QTL for HR and SBP may differ in males and females and may be sensitive to different environmental contexts.