Baseline characteristics of participants in the African American Study of Kidney Disease and Hypertension (AASK) Clinical Trial and Cohort Study.

Background: African Americans are at increased risk of kidney failure caused by hypertension. The primary objective of the African American Study of Kidney Disease and Hypertension (AASK) Cohort Study is to identify risk factors for progressive kidney disease in African Americans with hypertensive chronic kidney disease in the setting of recommended antihypertensive therapy.

Study Design, Setting, & Participants: On completion of the AASK Trial, a randomized, double-blind, 3 x 2 factorial trial, participants who had not yet begun dialysis treatment or undergone kidney transplantation were invited to enroll in a prospective Cohort Study.

Oxidative signaling in renal epithelium: Critical role of cytosolic phospholipase A2 and p38(SAPK).

Previous studies from this laboratory have demonstrated a critical role of cytosolic phospholipase A2 (cPLA2) and arachidonic acid in angiotensin II (Ang II) AT2 receptor-mediated signal transduction in renal epithelium. In primary proximal tubular epithelial cells exposed to hydrogen peroxide (H2O2), both the selective cPLA2 inhibitors and the cPLA2 antisense oligonucleotides significantly attenuated H2O2-induced arachidonic acid liberation and activation of p38(SAPK), ERK1/2, and Akt1. This H2O2-induced kinase activation was significantly attenuated by a Src kinase inhibitor PP2, or by transient transfection of carboxyl-terminal Src kinase (CSK) that maintained Src in the dormant form.

Functional diversity of AT2 receptor orthologues in closely related species.

Background: The most striking feature of life is biodiversity. However, mechanisms of biodiversity remain poorly understood, as most protein orthologues of different species are highly homologous in sequence and identical in function. Interestingly, recent evidence has demonstrated heterogeneity for a G protein-coupled angiotensin II (Ang II) type 2 (AT(2)) receptor in both ligand binding and induction of arachidonic acid (AA) release.

Improving cardiovascular health outcomes through the use of evidence-based medicine.

The risk of cardiovascular (CV) and renal complications begins at a relatively low blood pressure (BP), and this risk is associated with such disorders as metabolic syndrome. When comparing older antihypertensive agents with newer agents, for the most part no significant differences have been seen in rates of CV events. However, rapidly controlling BP is critical to reduce event rates, particularly rates of stroke.

Clinical guidelines for the treatment of hypertension in African Americans.

African Americans represent a population with the highest prevalence of hypertension in the world, associated with earlier onset, more severity, poorer control rates, and more cardiovascular and renal complications than White Americans. The high prevalence of type 2 diabetes mellitus in African Americans, compared with Whites, compounds the excessive burden of cardiovascular and kidney disease. The Hypertension in African American Working Group of the International Society of Hypertension in Blacks recently developed a consensus document that presented a practical, evidence-based approach aimed at achieving better blood pressure control.

A comparison of iothalamate-GFR and serum creatinine-based outcomes: acceleration in the rate of GFR decline in the African American Study of Kidney Disease and Hypertension.

In renal clinical trials, both slope-based and time-to-event renal outcomes have been used. These outcomes are typically based on estimates of GFR obtained using creatinine or iothalamate GFR (iGFR). The African American Study of Kidney Disease and Hypertension (AASK) was a trial in 1094 African Americans with hypertensive nephrosclerosis, which examined the effects of two levels of BP control and three antihypertensive regimens.

Cardiovascular risk reduction in hypertensive black patients with left ventricular hypertrophy: the LIFE study.

Objectives: We report on a subanalysis of the effects of losartan and atenolol on cardiovascular events in black patients in the Losartan Intervention For Endpoint reduction in hypertension (LIFE) study.

Background: The LIFE study compared losartan-based to atenolol-based therapy in 9,193 hypertensive patients with left ventricular hypertrophy (LVH). Overall, the risk of the primary composite end point (cardiovascular death, stroke, myocardial infarction) was reduced by 13% (p = 0.

Growth, immortalization, and differentiation potential of normal adult human proximal tubule cells.

Human proximal tubule epithelial cell lines are potentially useful models to elucidate the complex cellular and molecular details of water and electrolyte homeostasis in the kidney. Samples of normal adult human kidney tissue were obtained from surgical specimens, and S1 segments of proximal convoluted tubules were microdissected, placed on collagen-coated culture plate inserts, and cocultured with lethally irradiated 3T3 fibroblasts. Primary cultures of proximal tubule epithelial cells were infected with a replication-defective retroviral construct encoding either wild-type or temperature-sensitive simian virus 40 large T-antigen.

Cyclic stretch-induced cPLA2 mediates ERK 1/2 signaling in rabbit proximal tubule cells.

Background: Recent evidence from this laboratory have demonstrated a critical role of phospholipase A2 (PLA2) and arachidonic acid in angiotensin II type 2 (AT2) receptor-mediated kinase activation in renal epithelium independent of phosphoinositide- specific phospholipase C (PLC) and without the necessity of eicosanoid biosynthesis. In the present study, we investigated whether cyclic stress phosphorylates and activates the mitogen-activated protein kinase (MAPK) pathway and whether PLA2 activation mediates mechanotransduction in renal epithelial cells. The rational for studying kidney epithelial cells relates to their similarity to podocytes, which undergo mechanical stretch related to changes in intraglomerular pressure.

Determinants of salt sensitivity in black and white normotensive and hypertensive women.

Salt sensitivity (SS) has been linked to human hypertension. We examined ethnic differences in the relation between SS; erythrocyte sodium (Na+i), calcium (Ca2+i), potassium (K+i), and magnesium (Mg2+i); and sodium pump activity in African-American (AA) and white women. In a crossover protocol, similar numbers of normotensive, hypertensive, AA, and white women were randomized to 7 days of a 20 meq/d and a >200 meq/d salt diet (n=199).

ACE inhibition is effective and renoprotective in hypertensive nephrosclerosis: the African American Study of Kidney Disease and Hypertension (AASK) trial.

An interim analysis of the AASK trial at three years demonstrates a renoprotective effect [slower decline in glomerular filtration rate (GFR), delayed onset of significant decrease in GFR, end-stage renal disease (ESRD) or death, and a decrease in urinary protein excretion] of the angiotensin converting enzyme (ACE) inhibitor, ramipril, as compared to the dihydropyridine calcium channel blocker (DHP-CCB), amlodipine, in patients with mild-to-moderate renal insufficiency. The beneficial effect occurred in the presence of similar levels of blood pressure control and was apparent in patients with proteinuric (beyond the threshold of "dipstick positive" proteinuria, 300 mg/day) and non-proteinuric hypertensive nephrosclerosis. At the time of the interim analysis, the effectiveness of the beta-blocker metoprolol was not significantly different from that of the ACE inhibitor.

Effects of blood pressure level on progression of diabetic nephropathy: results from the RENAAL study.

Background: Clinical trials of nephropathy in people with type 2 diabetes mellitus have not examined the effects of systolic blood pressure (SBP) or pulse pressure (PP) on the time to end-stage renal disease (ESRD) or death.

Objectives: To evaluate the impact of baseline and treated SBP, diastolic blood pressure (DBP), and PP on composite and individual outcomes including doubling of serum creatinine, ESRD, or death in participants of the Reduction of Endpoints in NIDDM (non-insulin-dependent diabetes mellitus) With the Angiotensin II Antagonist Losartan (RENAAL) Study; to assess the specific effect of the angiotensin receptor blocker losartan potassium on composite and renal outcomes; and to explore the implications of dihydropyridine calcium channel blockers as concurrent therapy on composite and renal outcomes.

Design: A Cox proportional hazards regression model was used to assess the hazard risk profile of baseline SBP (categories: <130, 130-139, 140-159, 160-179, and > or =180 mm Hg), DBP (categories: <70, 70-79, 80-89, 90-99, and > or =100 mm Hg), and PP (categories: <60, 60-69, 70-79, 80-89, and > or =90 mm Hg) on renal outcomes.

The rationale and design of the AASK cohort study.

Hypertensive kidney disease commonly progresses. The primary objective of the AASK (African American Study of Kidney Disease and Hypertension) Cohort Study is to determine prospectively the course of kidney function and risk factors for kidney disease progression in African Americans with hypertensive kidney disease who receive recommended anti-hypertensive therapy. The AASK Cohort Study is a prospective, observational study that is an extension of the AASK trial.

Design and statistical aspects of the African American Study of Kidney Disease and Hypertension (AASK).

The African American Study of Kidney Disease and Hypertension (AASK) is a multicenter randomized clinical trial designed to test the effectiveness of three anti-hypertensive drug regimens and two levels of BP control on the progression of hypertensive kidney disease. Participants include African-American men and women aged 18 to 70 yr who have hypertensive kidney disease and GFR between 20 and 65 ml/min per 1.73 m(2).

Optimal treatment of hypertension and cardiovascular risk reduction in African Americans: treatment approaches for outpatients.

African Americans have a higher prevalence and greater severity of hypertension compared with whites and therefore have a higher prevalence of many disease-related complications, such as coronary heart disease, stroke, and end-stage renal disease. Minorities have been, until recently, underrepresented in large clinical trials, leading to a lack of outcome data for these patient groups. However, accumulating data confirm the benefit of aggressive blood pressure-lowering therapy in this population.

Hypertension-related disease in African Americans. Factors underlying disparities in illness and its outcome.

African Americans have a higher prevalence of hypertension, diabetes, cardiovascular disease (CVD), stroke, and renal disease than white Americans. The high rates of diabetes and hypertension in children and of type 2 diabetes, stroke, and CVD in women are particularly striking. In this article, Drs Sowers, Ferdinand, Bakris, and Douglas examine the biologic, social, and genetic factors that contribute to these health disparities, the risk for which appears in early childhood.

Optimal treatment of hypertension in African Americans. Reaching and maintaining target blood pressure goals.

Treatment of hypertension in African Americans has special challenges, including a lack of objective trial data on which to base decisions and differing benefits and responses than with other patients. However, adequate control is possible and should be the goal of treating physicians. This article describes current "best practice" guidance on appropriate treatment of high blood pressure in African Americans.

Barriers to blood pressure control in African Americans. Overcoming obstacles is challenging, but target goals can be attained.

Outdated and biased attitudes and care standards impede optimal care of hypertension in African Americans. The negative expectations that blood pressure targets cannot be reached must be overcome by systematic and appropriate education and treatment. However, physicians should expect that (1) African American patients with elevated blood pressure benefit from early and intensive management, (2) blood pressure can be maintained at goal with appropriate therapeutic lifestyle changes and medications, and (3) complications related to high blood pressure can be avoided.

Gbeta gamma -independent constitutive association of Galpha s with SHP-1 and angiotensin II receptor AT2 is essential in AT2-mediated ITIM-independent activation of SHP-1.

Conventional mode of activation of SH2 domain-containing phosphatase 1 (SHP-1) by a single transmembrane (TM) inhibitory receptor such as killer cell inhibitory receptor, Fcgamma receptor type IIb1, and paired Ig-like receptors of inhibitory types requires tyrosine phosphorylation of immunoreceptor tyrosine-based inhibitory (ITIM) motifs in the cytoplasmic domains of the inhibitory receptors. Contrary to this paradigm, AT(2), a G protein-coupled 7TM receptor that does not undergo tyrosine phosphorylation in response to angiotensin II (Ang II) stimulation, also activates SHP-1. Here we show that SHP-1 constitutively and physically associates with AT(2) receptor in transfected COS-7 cells.

Successful blood pressure control in the African American Study of Kidney Disease and Hypertension.

Background: The African American Study of Kidney Disease and Hypertension (AASK) is an ongoing trial to evaluate the effect of blood pressure and choice of antihypertensive drug on the rate of decline of renal function.

Objective: To present the success of the AASK in achieving the trial's rigorous blood pressure goals in an extremely challenging patient population.

Methods: The AASK participants included African American patients with hypertension (n = 1094), aged 18 to 70 years, with glomerular filtration rates between 20 and 65 mL/min per 1.