CKD and cardiovascular disease in the Atherosclerosis Risk in Communities (ARIC) study: interactions with age, sex, and race

Cardiac and vascular changes with kidney transplantation

Cardiovascular event rates are high in patients with chronic kidney disease (CKD), increasing with deteriorating kidney function, highest in CKD patients on dialysis, and improve with kidney transplantation (KTx). The cardiovascular events in CKD patients such as myocardial infarction and heart failure are related to abnormalities of vascular and cardiac structure and function. Many studies have investigated the structural and functional abnormalities of the heart and blood vessels in CKD, and the changes that occur with KTx, but the evidence is often sparse and occasionally contradictory. We have reviewed the available evidence and identified areas where more research is required to improve the understanding and mechanisms of these changes. There is enough evidence demonstrating improvement of left ventricular hypertrophy, except in children, and sufficient evidence of improvement of left ventricular function, with KTx. There is reasonable evidence of improvement in vascular function and stiffness. However, the evidence for improvement of vascular structure and atherosclerosis is insufficient. Further studies are necessary to establish the changes in vascular structure, and to understand the mechanisms of vascular and cardiac changes, following KTx.

Apolipoprotein L1: from obscurity to consistency to controversy

Apolipoprotein L1 (APOL1) is associated with increased incidence of chronic kidney disease (CKD) and end-stage renal disease, and with faster progression of CKD, in African Americans. APOL1 is expressed in intra- and extrarenal vascular tissue, making it a candidate to explain the increased incidence of cardiovascular disease in CKD. This Commentary discusses the disparate results from three studies showing that APOL1 renal risk genotypes are either harmful, neutral, or protective in the context of cardiovascular disease.

Kidney Function and Cardiovascular Events in Postmenopausal Women: The Impact of Race and Ethnicity in the Women's Health Initiative

BACKGROUND

Kidney disease disproportionately affects minority populations, including African Americans and Hispanics; therefore, understanding the relationship of kidney function to cardiovascular (CV) outcomes within different racial/ethnic groups is of considerable interest. We investigated the relationship between kidney function and CV events and assessed effect modification by race/ethnicity in the Women's Health Initiative.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

Baseline serum creatinine concentrations (assay traceable to isotope-dilution mass spectrometry standard) of 19,411 postmenopausal women aged 50 to 79 years who self-identified as either non-Hispanic white (n=8,921), African American (n=7,436), or Hispanic (n=3,054) were used to calculate estimated glomerular filtration rates (eGFRs).

PREDICTORS

Categories of eGFR (exposure); race/ethnicity (effect modifier).

OUTCOMES

The primary outcome was the composite of 3 physician-adjudicated CV events: myocardial infarction, stroke, or CV-related death.

MEASUREMENTS

We evaluated the multivariable-adjusted associations between categories of eGFR and CV events using proportional hazards regression and formally tested for effect modification by race/ethnicity.

RESULTS

During a mean follow-up of 7.6 years, 1,424 CV events (653 myocardial infarctions, 627 strokes, and 297 CV-related deaths) were observed. The association between eGFR and CV events was curvilinear; however, the association of eGFR with CV outcomes differed by race (P=0.006). In stratified analyses, we observed that the U-shaped association was present in non-Hispanic whites, whereas African American participants had a rather curvilinear relationship, with lower eGFR being associated with higher CV risk, and higher eGFR, with reduced CV risk. Analyses among Hispanic women were inconclusive owing to few Hispanic women having very low or high eGFRs and very few events occurring in these categories.

LIMITATIONS

Lack of urinary albumin measurements; residual confounding by unmeasured or imprecisely measured characteristics.

CONCLUSIONS

In postmenopausal women, the patterns of association between eGFR and CV risk differed between non-Hispanic whites and African American women.

Elevated sodium and dehydration stimulate inflammatory signaling in endothelial cells and promote atherosclerosis

Cardiovascular diseases (CVDs) are a leading health problem worldwide. Epidemiologic studies link high salt intake and conditions predisposing to dehydration such as low water intake, diabetes and old age to increased risk of CVD. Previously, we demonstrated that elevation of extracellular sodium, which is a common consequence of these conditions, stimulates production by endothelial cells of clotting initiator, von Willebrand Factor, increases its level in blood and promotes thrombogenesis. In present study, by PCR array, using human umbilical vein endothelial cells (HUVECs), we analyzed the effect of high NaCl on 84 genes related to endothelial cell biology. The analysis showed that the affected genes regulate many aspects of endothelial cell biology including cell adhesion, proliferation, leukocyte and lymphocyte activation, coagulation, angiogenesis and inflammatory response. The genes whose expression increased the most were adhesion molecules VCAM1 and E-selectin and the chemoattractant MCP-1. These are key participants in the leukocyte adhesion and transmigration that play a major role in the inflammation and pathophysiology of CVD, including atherosclerosis. Indeed, high NaCl increased adhesion of mononuclear cells and their transmigration through HUVECs monolayers. In mice, mild water restriction that elevates serum sodium by 5 mmol/l, increased VCAM1, E-selectin and MCP-1 expression in mouse tissues, accelerated atherosclerotic plaque formation in aortic root and caused thickening or walls of coronary arteries. Multivariable linear regression analysis of clinical data from the Atherosclerosis Risk in Communities Study (n=12779) demonstrated that serum sodium is a significant predictor of 10 Years Risk of coronary heart disease. These findings indicate that elevation of extracellular sodium within the physiological range is accompanied by vascular changes that facilitate development of CVD. The findings bring attention to serum sodium as a risk factor for CVDs and give additional support to recommendations for dietary salt restriction and adequate water intake as preventives of CVD.

Contrasting Cholesterol Management Guidelines for Adults with CKD

The Kidney Disease Improving Global Outcomes Lipid Work Group recommends statins for adults ≥50 years old with CKD. The American College of Cardiology/American Heart Association endorses statins for adults with atherosclerotic cardiovascular disease, adults with LDL cholesterol≥190 mg/dl, and adults 40-79 years old with LDL cholesterol=70-189 mg/dl and diabetes or a 10-year predicted risk for atherosclerotic cardiovascular disease ≥7.5% estimated using the Pooled Cohort risk equations. Using data from the Reasons for Geographic and Racial Differences in Stroke Study, we calculated the agreement for statin treatment between these two guidelines for adults 50-79 years old with CKD (eGFR<60 ml/min per 1.73 m(2) or albuminuria≥30 mg/g) not on dialysis. We assessed the validity of the Pooled Cohort risk equations in individuals with CKD. Study participants were enrolled between 2003 and 2007, and we report incident cardiovascular disease events (stroke and coronary heart disease) through December of 2010. Among 4726 participants with CKD, 2366 (50%) were taking statins, and 1984 (42%) were recommended statins by the American College of Cardiology/American Heart Association guideline but not taking them. Overall, 376 (8%) participants did not meet the American College of Cardiology/American Heart Association criteria for initiating statin treatment. Cardiovascular disease incidence was low (3.0/1000 person-years; 95% confidence interval, 0.1 to 5.9) among these participants. The Pooled Cohort risk equations were well calibrated (Hosmer-Lemeshow chi-squared=2.7, P=0.45) with moderately good discrimination (C index, 0.71; 95% confidence interval, 0.65 to 0.77). In conclusion, these guidelines show high concordance for statin treatment for adults with CKD.

Patients with biopsy-proven nephrosclerosis and moderately impaired renal function have a higher risk for cardiovascular disease: 15 years' experience in a single, kidney disease center

BACKGROUND

Nephrosclerosis progresses slowly to end-stage renal disease (ESRD) in only a small percentage of patients. However, because hypertension and nephrosclerosis are normally found simultaneously, nephrosclerosis is a risk factor for cardiovascular disease (CVD). In turn, the onset of CVD may progress to further renal impairment.

AIM

To evaluate clinical outcomes and the association between nephrosclerosis and CVD in the long term.

DESIGN

Prospective study

METHODS

We prospectively assessed 35 patients (male/female: 19/16) with nephrosclerosis aged >30 years at disease onset, attending the Kidney Disease Center, Saitama Medical University, in a single teaching hospital center between 1995 and 2014. Nephrosclerosis was diagnosed in accordance with the criteria outlined in the World Health Organization (WHO) monograph of renal diseases. All patients were followed by means of registries for 10 years to record subsequent events, if any.

OUTCOMES

The primary study outcome was correlating the occurrence of CVD, defined as a composite of cardiovascular deaths, nonfatal and fatal myocardial infarction, and stroke, with the development of ESRD or death.

RESULTS

The mean age of patients at the time of biopsy was 54.8 ± 12.7 years (range 33-72 years). Of these patients, seven were affected by nonfatal CVD and two died due to CVD. Only one patient developed ESRD during the follow-up period. Using Kaplan-Meier analysis, risk factors for the primary study outcome were estimated to include an estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m(2), systolic blood pressure > 130 mmHg and proteinuria > 1 g/g creatinine. Univariate analysis was used for the assessment of the relative risk for the primary study endpoint of several covariates: age, systolic blood pressure, eGFR and proteinuria at time of renal biopsy. eGFR was found to be the strongest factor determining an event-free period [relative risk (RR) =1.931, p = 0.014].

CONCLUSIONS

Patients with nephrosclerosis are at high risk of CVD when they have moderately advanced renal impairment.

Aging, the metabolic syndrome, and ischemic stroke: redefining the approach for studying the blood-brain barrier in a complex neurological disease

The blood-brain barrier (BBB) has many important functions in maintaining the brain's immune-privileged status. Endothelial cells, astrocytes, and pericytes have important roles in preserving vasculature integrity. As we age, cell senescence can contribute to BBB compromise. The compromised BBB allows an influx of inflammatory cytokines to enter the brain. These cytokines lead to neuronal and glial damage. Ultimately, the functional changes within the brain can cause age-related disease. One of the most prominent age-related diseases is ischemic stroke. Stroke is the largest cause of disability and is third largest cause of mortality in the United States. The biggest risk factors for stroke, besides age, are results of the metabolic syndrome. The metabolic syndrome, if unchecked, quickly advances to outcomes that include diabetes, hypertension, cardiovascular disease, and obesity. The contribution from these comorbidities to BBB compromise is great. Some of the common molecular pathways activated include: endoplasmic reticulum stress, reactive oxygen species formation, and glutamate excitotoxicity. In this chapter, we examine how age-related changes to cells within the central nervous system interact with comorbidities. We then look at how comorbidities lead to increased risk for stroke through BBB disruption. Finally, we discuss key molecular pathways of interest with a focus on therapeutic targets that warrant further investigation.

Overview of cardiac markers in heart disease

Cardiac troponins I and T have been the cornerstone of diagnostics of acute coronary syndrome for almost 20 years. Natriuretic peptides have established themselves in heart failure during the last decade. These and additional promising biomarkers, such as ST-2, galectin-3, GDF-15, copeptin, midregional proadrenomedullin, and the markers of glomerular filtration rate and kidney injury, are reviewed in groups corresponding to the pathophysiological processes they probe--cardiomyocyte injury, myocyte stress, inflammation, oxidative stress, plaque instability, extracellular-matrix remodeling, or those markers grouped in the neurohormone category. Biomarkers linking the renal and cardiac functions and microRNAs and metabolomic markers are addressed as well.

Orthostatic hypertension-a new haemodynamic cardiovascular risk factor

Orthostatic hypertension-a condition characterized by a hyperactive pressor response to orthostatic stress-is an emerging risk factor for cardiovascular disease and is associated with hypertensive target-organ damage (resulting in silent cerebrovascular disease, left ventricular hypertrophy, carotid atherosclerosis and/or chronic kidney disease) and cardiovascular events (such as coronary artery disease and lacunar stroke). The condition is also considered to be a form of prehypertension as it precedes hypertension in young, normotensive adults. Orthostatic blood pressure changes can be assessed using orthostatic stress tests, including clinic active standing tests, home blood pressure monitoring and the head-up tilting test. Devices for home and for ambulatory blood pressure monitoring that are equipped with position sensors and do not induce a white-coat effect have increased the sensitivity and specificity of diagnosis of out-of-clinic orthostatic hypertension. Potential major mechanisms of orthostatic hypertension are sympathetic hyperactivity (as a result of hypersensitivity of the cardiopulmonary and arterial baroreceptor reflex) and α-adrenergic hyperactivation. Orthostatic hypertension is also associated with morning blood pressure surge and extreme nocturnal blood pressure dipping, both of which increase the pulsatile haemodynamic stress of central arterial pressure and blood flow in patients with systemic haemodynamic atherothrombotic syndrome.