Chymase in Plasma and Urine Extracellular Vesicles: Novel Biomarkers for Primary Hypertension.

BACKGROUND: Extracellular vesicles (EVs) have emerged as a promising liquid biopsy for various diseases. For the first time, using plasma and urinary EVs, we assessed the activity of renin-angiotensin system (RAS), a central regulator of renal, cardiac, and vascular physiology, in patients with control (Group I) or uncontrolled (Group II) primary hypertension. METHODS: EVs were isolated from 34 patients with history of hypertension, and characterized for size and concentration by nanoparticle tracking analyses, exosomal biomarkers by immunogold labeling coupled with transmission electron microscopy, flow cytometry and immunoblotting. EVs were analyzed for the hydrolytic activity of chymase, angiotensin converting enzyme (ACE), ACE2, and neprilysin (NEP) by HPLC. RESULTS: Plasma and urinary EVs were enriched for small EVs and expressed exosomal markers (CD63, CD9, and CD81). The size of urinary EVs (but not plasma EVs) was significantly larger in Group II compared to Group I. Differential activity of RAS enzymes was observed, with significantly higher chymase activity compared to ACE, ACE2, and NEP in plasma EVs. Similarly, urinary EVs exhibited higher chymase and NEP activity compared to ACE and ACE2 activity. Importantly, compared to Group I, significantly higher chymase activity was observed in urinary EVs (p = 0.03) from Group II, while no significant difference in activity was observed for other RAS enzymes. CONCLUSIONS: Bioactive RAS enzymes are present in plasma and urinary EVs. Detecting chymase in plasma and urinary EVs uncovers a novel mechanism of angiotensin II-forming enzyme and could also mediate cell-cell communication and modulate signaling pathways in recipient cells.

A Liquid Biopsy-Based Approach to Isolate and Characterize Adipose Tissue-Derived Extracellular Vesicles from Blood.

Obesity is a major risk factor for multiple chronic diseases. Anthropometric and imaging approaches are primarily used to assess adiposity, and there is a dearth of techniques to determine the changes in adipose tissue (AT) at the molecular level. Extracellular vesicles (EVs) have emerged as a novel and less invasive source of biomarkers for various pathologies. Furthermore, the possibility of enriching cell or tissue-specific EVs from the biofluids based on their unique surface markers has led to classifying these vesicles as "liquid biopsies", offering valuable molecular information on hard-to-access tissues. Here, we isolated small EVs from AT (sEVAT) of lean and diet-induced obese (DIO) mice, identified unique surface proteins on sEVAT by surface shaving followed by mass spectrometry, and developed a signature of five unique proteins. Using this signature, we pulled out sEVAT from the blood of mice and validated the specificity of isolated sEVAT by measuring the expression of adiponectin, 38 adipokines on an array, and several adipose tissue-related miRNAs. Furthermore, we provided evidence of sEV applicability in disease prediction by characterizing sEVAT from the blood of lean and DIO mice. Interestingly, sEVAT-DIO cargo showed a stronger pro-inflammatory effect on THP1 monocytes compared to sEVAT-Lean and a significant increase in obesity-associated miRNA expression. Equally important, sEVAT cargo revealed an obesity-associated aberrant amino acid metabolism that was subsequently validated in the corresponding AT. Lastly, we show a significant increase in inflammation-related molecules in sEVAT isolated from the blood of nondiabetic obese (>30 kg/m2) individuals. Overall, the present study offers a less-invasive approach to characterize AT.

Intensive Versus Standard Blood Pressure Lowering and Days Free of Cardiovascular Events and Serious Adverse Events: a Post Hoc Analysis of Systolic Blood Pressure Intervention Trial.

BACKGROUND: Communication of the benefits and harms of blood pressure lowering strategy is crucial for shared decision-making. OBJECTIVES: To quantify the effect of intensive versus standard systolic blood pressure lowering in terms of the number of event-free days DESIGN: Post hoc analysis of the Systolic Blood Pressure Intervention Trial PARTICIPANTS: A total of 9361 adults 50 years or older without diabetes or stroke who had a systolic blood pressure of 130-180 mmHg and elevated cardiovascular risk INTERVENTIONS: Intensive (systolic blood pressure goal <120 mmHg) versus standard blood pressure lowering (<140 mmHg) MAIN MEASURES: Days free of major adverse cardiovascular events (MACE), serious adverse events (SAE), and monitored adverse events (hypotension, syncope, bradycardia, electrolyte abnormalities, injurious falls, or acute kidney injury) over a median follow-up of 3.33 years KEY RESULTS: The intensive treatment group gained 14.7 more MACE-free days over 4 years (difference, 14.7 [95% confidence interval: 5.1, 24.4] days) than the standard treatment group. The benefit of the intensive treatment varied by cognitive function (normal: difference, 40.7 [13.0, 68.4] days; moderate-to-severe impairment: difference, -15.0 [-56.5, 26.4] days; p-for-interaction=0.009) and self-rated health (excellent: difference, -22.7 [-51.5, 6.1] days; poor: difference, 156.1 [31.1, 281.2] days; p-for-interaction=0.001). The mean overall SAE-free days were not significantly different between the treatments (difference, -14.8 [-35.3, 5.7] days). However, the intensive treatment group had 28.5 fewer monitored adverse event-free days than the standard treatment group (difference, -28.5 [-40.3, -16.7] days), with significant variations by frailty status (non-frail: difference, 38.8 [8.4, 69.2] days; frail: difference, -15.5 [-46.6, 15.7] days) and self-rated health (excellent: difference, -12.9 [-45.5, 19.7] days; poor: difference, 180.6 [72.9, 288.4] days; p-for-interaction <0.001). CONCLUSIONS: Over 4 years, intensive systolic blood pressure lowering provides, on average, 14.7 more MACE-free days than standard treatment, without any difference in SAE-free days. Whether this time-based effect summary improves shared decision-making remains to be elucidated. TRIAL REGISTRATION: ClinicalTrials.gov Registration: NCT01206062.

Association of Intensive vs Standard Blood Pressure Control With Cerebral Blood Flow: Secondary Analysis of the SPRINT MIND Randomized Clinical Trial.

IMPORTANCE: Antihypertensive treatments benefit cerebrovascular health and cognitive function in patients with hypertension, but it is uncertain whether an intensive blood pressure target leads to potentially harmful cerebral hypoperfusion. OBJECTIVE: To investigate the association of intensive systolic blood pressure (SBP) control vs standard control with whole-brain cerebral blood flow (CBF). DESIGN, SETTING, AND PARTICIPANTS: This substudy of the Systolic Blood Pressure Intervention Trial (SPRINT) randomized clinical trial compared the efficacy of 2 different blood pressure-lowering strategies with longitudinal brain magnetic resonance imaging (MRI) including arterial spin labeled perfusion imaging to quantify CBF. A total of 1267 adults 50 years or older with hypertension and increased cardiovascular risk but free of diabetes or dementia were screened for the SPRINT substudy from 6 sites in the US. Randomization began in November 2010 with final follow-up MRI in July 2016. Analyses were performed from September 2020 through December 2021. INTERVENTIONS: Study participants with baseline CBF measures were randomized to an intensive SBP target less than 120 mm Hg or standard SBP target less than 140 mm Hg. MAIN OUTCOMES AND MEASURES: The primary outcome was change in whole-brain CBF from baseline. Secondary outcomes were change in gray matter, white matter, and periventricular white matter CBF. RESULTS: Among 547 participants with CBF measured at baseline, the mean (SD) age was 67.5 (8.1) years and 219 (40.0%) were women; 315 completed follow-up MRI at a median (IQR) of 4.0 (3.7-4.1) years after randomization. Mean whole-brain CBF increased from 38.90 to 40.36 (difference, 1.46 [95% CI, 0.08-2.83]) mL/100 g/min in the intensive treatment group, with no mean increase in the standard treatment group (37.96 to 37.12; difference, -0.84 [95% CI, -2.30 to 0.61] mL/100 g/min; between-group difference, 2.30 [95% CI, 0.30-4.30; P = .02]). Gray, white, and periventricular white matter CBF showed similar changes. The association of intensive vs standard treatment with CBF was generally similar across subgroups defined by age, sex, race, chronic kidney disease, SBP, orthostatic hypotension, and frailty, with the exception of an indication of larger mean increases in CBF associated with intensive treatment among participants with a history of cardiovascular disease (interaction P = .05). CONCLUSIONS AND RELEVANCE: Intensive vs standard antihypertensive treatment was associated with increased, rather than decreased, cerebral perfusion, most notably in participants with a history of cardiovascular disease. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01206062.

Newly developed radioimmunoassay for Human Angiotensin-(1-12) measurements in plasma and urine.

The dodecapeptide angiotensin-(1-12) [Ang-(1-12)] functions as an intracrine/paracrine substrate for local production of angiotensin II. We developed a reliable and specific radioimmunoassay (RIA) method for the measurement of Ang-(1-12) in human plasma and urine using an affinity purified antibody fraction directed towards the C-terminus of the human Ang-(1-12) sequence. The RIA method was applied to quantify the Ang-(1-12) in plasma and urine collected from thirty-four human subjects (29 treated with antihypertensive medicines and 5 untreated patients). Plasma Ang-(1-12) level was significantly higher (P < 0.05) in patients with systolic blood pressure ≥140 mm Hg (n = 10) compared to the group with systolic blood pressure <140 mm Hg (n = 24). No significant difference (P = 0.22) was found in spot urine between the groups. Our study also shows that the polyclonal antibody neutralizes the cleavage sites of the human Ang-(1-12) from recombinant human chymase (rhChymase) and serum angiotensin converting enzyme (ACE) mediated Ang II generating hydrolysis. Overall, this newly developed RIA method is reliable and applicable to accurately quantify the Ang-(1-12) level in clinical samples (plasma and urine). Further, our in vitro neutralization study suggests that the anti-Ang-(1-12)-antibody might be used as an in vivo therapeutic agent for preventing Ang-(1-12)/Ang II-mediated hypertension and organ damage.

Effect of Intensive Blood Pressure Control on Aortic Stiffness in the SPRINT-HEART.

[Figure: see text].

Chronic kidney disease, atherosclerotic plaque characteristics on carotid magnetic resonance imaging, and cardiovascular outcomes.

BACKGROUND: It is unclear whether faster progression of atherosclerosis explains the higher risk of cardiovascular events in CKD. The objectives of this study were to 1. Characterize the associations of CKD with presence and morphology of atherosclerotic plaques on carotid magnetic resonance imaging (MRI) and 2. Examine the associations of baseline CKD and carotid atherosclerotic plaques with subsequent cardiovascular events. METHODS: In a subgroup (N = 465) of Systolic Blood Pressure Intervention Trial. (SPRINT) participants, we measured carotid plaque presence and morphology at baseline and after 30-months with MRI. We examined the associations of CKD (baseline eGFR < 60 ml/min/1.73m2) with progression of carotid plaques and the SPRINT cardiovascular endpoint. RESULTS: One hundred and ninety six (42%) participants had CKD. Baseline eGFR in the non-CKD and CKD subgroups were 77 ± 14 and 49 ± 8 ml/min/1.73 m2, respectively. Lipid rich necrotic-core plaque was present in 137 (29.5%) participants. In 323 participants with both baseline and follow-up MRI measurements of maximum wall thickness, CKD was not associated with progression of maximum wall thickness (OR 0.62, 95% CI 0.36 to 1.07, p = 0.082). In 96 participants with necrotic core plaque at baseline and with a valid follow-up MRI, CKD was associated with lower odds of progression of necrotic core plaque (OR 0.41, 95% CI 0.17 to 0.95, p = 0.039). There were 28 cardiovascular events over 1764 person-years of follow-up. In separate Cox models, necrotic core plaque (HR 2.59, 95% CI 1.15 to 5.85) but not plaque defined by maximum wall thickness or presence of a plaque component (HR 1.79, 95% CI 0.73 to 4.43) was associated with cardiovascular events. Independent of necrotic core plaque, CKD (HR 3.35, 95% CI 1.40 to 7.99) was associated with cardiovascular events. CONCLUSIONS: Presence of necrotic core in carotid plaque rather than the presence of plaque per se was associated with increased risk of cardiovascular events. We did not find CKD to be associated with faster progression of necrotic core plaques, although both were independently associated with cardiovascular events. Thus, CKD may contribute to cardiovascular disease principally via mechanisms other than atherosclerosis such as arterial media calcification or stiffening. TRIAL REGISTRATION: NCT01475747 , registered on November 21, 2011.

FGF23, Frailty, and Falls in SPRINT.

BACKGROUND/OBJECTIVES: Chronic kidney disease (CKD) is associated with frailty. Fibroblast growth factor 23 (FGF23) is elevated in CKD and associated with frailty among non-CKD older adults and individuals with human immunodeficiency virus. Whether FGF23 is associated with frailty and falls in CKD is unknown. DESIGN: Cross-sectional and longitudinal observational study. SETTING: Systolic Blood Pressure Intervention Trial (SPRINT), a randomized trial evaluating standard (systolic blood pressure [SBP] <140 mm Hg) versus intensive (SBP <120 mm Hg) blood pressure lowering on cardiovascular and cognitive outcomes among older adults without diabetes mellitus. PARTICIPANTS: A total of 2,376 participants with CKD (estimated glomerular filtration rate [eGFR] <60 mL/min/1.73 m2 ). MEASUREMENTS: The exposure variable was intact FGF23. We used multinomial logistic regression to determine the cross-sectional association of intact FGF23 with frailty and Cox proportional hazards analysis to determine the longitudinal association with incident falls. Models were adjusted for demographics, comorbidities, randomization group, antihypertensives, eGFR, mineral metabolism markers, and frailty. RESULTS: After adjustment, the odds ratio for prevalent frailty versus non-frailty per twofold higher FGF23 was 1.34 (95% confidence interval [CI] = 1.01-1.77). FGF23 levels in the highest quartile versus the lowest quartile demonstrated more than a twofold increased fall risk (hazard ratio [HR] = 2.32; 95% CI = 1.26-4.26), and the HR per twofold higher FGF23 was 1.99 (95% CI = 1.48-2.68). CONCLUSION: Among SPRINT participants with CKD, FGF23 was associated with prevalent frailty and falls.

Tubular Biomarkers and Chronic Kidney Disease Progression in SPRINT Participants.

BACKGROUND: Kidney tubular atrophy on biopsy is a strong predictor of chronic kidney disease (CKD) progression, but tubular health is poorly quantified by traditional measures including estimated glomerular filtration rate (eGFR) and albuminuria. We hypothesized that urinary biomarkers of impaired tubule function would be associated with faster eGFR declines in persons with CKD. METHODS: We measured baseline urine concentrations of uromodulin, ß2-microglobulin (ß2m), and α1-microglobulin (α1m) among 2,428 participants of the Systolic Blood Pressure Intervention Trial with an eGFR <60 mL/min/1.73 m2. We used linear mixed models to evaluate biomarker associations with annualized relative change in eGFR, stratified by randomization arm. RESULTS: At baseline, the mean age was 73 ± 9 years and eGFR was 46 ± 11 mL/min/1.73 m2. In the standard blood pressure treatment arm, each 2-fold higher urinary uromodulin was associated with slower % annual eGFR decline (0.34 [95% CI: 0.08, 0.60]), whereas higher urinary ß2m was associated with faster % annual eGFR decline (-0.10 [95% CI: -0.18, -0.02]) in multivariable-adjusted models including baseline eGFR and albuminuria. Associations were weaker and did not reach statistical significance in the intensive blood pressure treatment arm for either uromodulin (0.11 [-0.13, 0.35], p value for interaction by treatment arm = 0.045) or ß2m (-0.01 [-0.08, 0.08], p value for interaction = 0.001). Urinary α1m was not independently associated with eGFR decline in the standard (0.01 [-0.22, 0.23]) or intensive (0.03 [-0.20, 0.25]) arm. CONCLUSIONS: Among trial participants with hypertension and CKD, baseline measures of tubular function were associated with subsequent declines in kidney function, although these associations were diminished by intensive blood pressure control.

Effects of Intensive Blood Pressure Control in Patients with and without Albuminuria: Post Hoc Analyses from SPRINT.

BACKGROUND AND OBJECTIVES: It is unclear whether the presence of albuminuria modifies the effects of intensive systolic BP control on risk of eGFR decline, cardiovascular events, or mortality. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: The Systolic Blood Pressure Intervention Trial randomized nondiabetic adults ≥50 years of age at high cardiovascular risk to a systolic BP target of <120 or <140 mm Hg, measured by automated office BP. We compared the absolute risk differences and hazard ratios of ≥40% eGFR decline, the Systolic Blood Pressure Intervention Trial primary cardiovascular composite outcome, and all-cause death in those with or without baseline albuminuria (urine albumin-creatinine ratio ≥30 mg/g). RESULTS: Over a median follow-up of 3.1 years, 69 of 1723 (4%) participants with baseline albuminuria developed ≥40% eGFR decline compared with 61 of 7162 (1%) participants without albuminuria. Incidence rates of ≥40% eGFR decline were higher in participants with albuminuria (intensive, 1.74 per 100 person-years; standard, 1.17 per 100 person-years) than in participants without albuminuria (intensive, 0.48 per 100 person-years; standard, 0.11 per 100 person-years). Although effects of intensive BP lowering on ≥40% eGFR decline varied by albuminuria on the relative scale (hazard ratio, 1.48; 95% confidence interval, 0.91 to 2.39 for albumin-creatinine ratio ≥30 mg/g; hazard ratio, 4.55; 95% confidence interval, 2.37 to 8.75 for albumin-creatinine ratio <30 mg/g; P value for interaction <0.001), the absolute increase in ≥40% eGFR decline did not differ by baseline albuminuria (incidence difference, 0.38 events per 100 person-years for albumin-creatinine ratio ≥30 mg/g; incidence difference, 0.58 events per 100 person-years for albumin-creatinine ratio <30 mg/g; P value for interaction =0.60). Albuminuria did not significantly modify the beneficial effects of intensive systolic BP lowering on cardiovascular events or mortality evaluated on relative or absolute scales. CONCLUSIONS: Albuminuria did not modify the absolute benefits and risks of intensive systolic BP lowering.

Urine Markers of Kidney Tubule Cell Injury and Kidney Function Decline in SPRINT Trial Participants with CKD.

BACKGROUND AND OBJECTIVES: eGFR and albuminuria primarily reflect glomerular function and injury, whereas tubule cell atrophy and interstitial fibrosis on kidney biopsy are important risk markers for CKD progression. Kidney tubule injury markers have primarily been studied in hospitalized AKI. Here, we examined the association between urinary kidney tubule injury markers at baseline with subsequent loss of kidney function in persons with nondiabetic CKD who participated in the Systolic Blood Pressure Intervention Trial (SPRINT). DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Among 2428 SPRINT participants with CKD (eGFR<60 ml/min per 1.73 m2) at baseline, we measured urine markers of tubule injury (IL-18, kidney injury molecule-1 [KIM-1], neutrophil gelatinase-associated lipocalin [NGAL]), inflammation (monocyte chemoattractant protein-1 [MCP-1]), and repair (human cartilage glycoprotein-40 [YKL-40]). Cox proportional hazards models evaluated associations of these markers with the kidney composite outcome of 50% eGFR decline or ESKD requiring dialysis or kidney transplantation, and linear mixed models evaluated annualized change in eGFR. RESULTS: Mean participant age was 73±9 (SD) years, 60% were men, 66% were white, and mean baseline eGFR was 46±11 ml/min per 1.73 m2. There were 87 kidney composite outcome events during a median follow-up of 3.8 years. Relative to the respective lowest quartiles, the highest quartiles of urinary KIM-1 (hazard ratio, 2.84; 95% confidence interval [95% CI], 1.31 to 6.17), MCP-1 (hazard ratio, 2.43; 95% CI, 1.13 to 5.23), and YKL-40 (hazard ratio, 1.95; 95% CI, 1.08 to 3.51) were associated with higher risk of the kidney composite outcome in fully adjusted models including baseline eGFR and urine albumin. In linear analysis, urinary IL-18 was the only marker associated with eGFR decline (-0.91 ml/min per 1.73 m2 per year for highest versus lowest quartile; 95% CI, -1.44 to -0.38), a finding that was stronger in the standard arm of SPRINT. CONCLUSIONS: Urine markers of tubule cell injury provide information about risk of subsequent loss of kidney function, beyond the eGFR and urine albumin.

Distinct Dimensions of Kidney Health and Risk of Cardiovascular Disease, Heart Failure, and Mortality.

Chronic kidney disease is a strong risk factor for cardiovascular disease (CVD), but clinical kidney measures (estimated glomerular filtration rate and albuminuria) do not fully reflect the multiple aspects of kidney tubules influencing cardiovascular health. Applied methods are needed to integrate numerous tubule biomarkers into useful prognostic scores. In SPRINT (Systolic Blood Pressure Intervention Trial) participants with chronic kidney disease at baseline (estimated glomerular filtration ratecr&cys <60 mL/minute per 1.73 m2), we measured 8 biomarkers from urine (α1M [α1M microglobulin], ß2M [ß2M microglobulin], umod [uromodulin], KIM-1 [kidney injury molecule-1], MCP-1 [monocyte chemoattractant protein-1], YKL-40 [chitinase-3-like protein-1], NGAL [neutrophil gelatinase-associated lipocalin], and IL-18 [interleukin 18]) and 2 biomarkers from serum (intact parathyroid hormone, iFGF-23 [intact fibroblast growth factor-23]). We used an unsupervised method, exploratory factor analysis, to create summary scores of tubule health dimensions. Adjusted Cox models evaluated each tubule score with CVD events, heart failure, and all-cause mortality. We examined CVD discrimination using Harrell C-statistic. Factor analysis of 10 biomarkers from 2376 SPRINT-chronic kidney disease participants identified 4 unique dimensions of tubular health: tubule injury/repair (NGAL, IL-18, YKL-40), tubule injury/fibrosis (KIM-1, MCP-1), tubule reabsorption (α1M, ß2M), and tubular reserve/mineral metabolism (umod, intact parathyroid hormone, iFGF-23). After adjustment for CVD risk factors, estimated glomerular filtration rate, and albumin-to-creatinine ratio, 2 of the 4 tubule scores were associated with CVD (hazard ratio per SD; reabsorption, 1.21 [1.06-1.38]; reserve, 1.24 (1.08-1.38]), 1 with heart failure (reserve, 1.41 [1.13-1.74]), and none with mortality. Compared with a base model (C-statistic=0.674), adding estimated glomerular filtration rate and albumin-to-creatinine ratio improved the C-statistic (C=0.704; P=0.001); further adding tubule scores additionally improved the C-statistic (C=0.719; P=0.009). In the setting of chronic kidney disease, dimensions of tubule health quantified using factor analysis improved CVD discrimination beyond contemporary kidney measures. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT01206062.

The SPRINT trial suggests that markers of tubule cell function in the urine associate with risk of subsequent acute kidney injury while injury markers elevate after the injury.

Urine markers can quantify tubular function including reabsorption (α-1 microglobulin [α1m]) and ß-2-microglobulin [ß2m]) and protein synthesis (uromodulin). Individuals with tubular dysfunction may be less able to compensate to insults than those without, despite similar estimated glomerular filtration rate (eGFR) and albuminuria. Among Systolic Blood Pressure Intervention Trial (SPRINT) participants with an eGFR under 60 ml/min/1.73m2, we measured urine markers of tubular function and injury (neutrophil gelatinase-associated lipocalin [NGAL], kidney injury molecule-1 [KIM-1], interleukin-18 [IL-18], monocyte chemoattractant protein-1, and chitinase-3-like protein [YKL-40]) at baseline. Cox models evaluated associations with subsequent acute kidney injury (AKI) risk, adjusting for clinical risk factors, baseline eGFR and albuminuria, and the tubular function and injury markers. In a random subset, we remeasured biomarkers after four years, and compared changes in biomarkers in those with and without intervening AKI. Among 2351 participants, 184 experienced AKI during 3.8 years mean follow-up. Lower uromodulin (hazard ratio per two-fold higher (0.68, 95% confidence interval [0.56, 0.83]) and higher α1m (1.20; [1.01, 1.44]) were associated with subsequent AKI, independent of eGFR and albuminuria. None of the five injury markers were associated with eventual AKI. In the random subset of 947 patients with repeated measurements, the 59 patients with intervening AKI versus without had longitudinal increases in urine NGAL, IL-19, and YKL-40 and only 1 marker of tubule function (α1m). Thus, joint evaluation of tubule function and injury provided novel insights to factors predisposing to AKI, and responses to kidney injury.

Markers of kidney tubule function and risk of cardiovascular disease events and mortality in the SPRINT trial.

AIMS: Biomarkers of kidney tubule injury, inflammation and fibrosis have been studied extensively and established as risk markers of adverse kidney and cardiovascular disease (CVD) outcomes. However, associations of markers of kidney tubular function with adverse clinical events have not been well studied, especially in persons with chronic kidney disease (CKD). METHODS AND RESULTS: Using a sample of 2377 persons with CKD at the baseline Systolic Blood Pressure Intervention Trial (SPRINT) visit, we evaluated the association of three urine tubular function markers, alpha-1 microglobulin (α1m), beta-2 microglobulin (ß2m), and uromodulin, with a composite CVD endpoint (myocardial infarction, acute coronary syndrome, stroke, acute decompensated heart failure, or death from cardiovascular causes) and mortality using Cox proportional hazards regression, adjusted for baseline estimated glomerular filtration rate (eGFR), albuminuria, and CVD risk factors. In unadjusted analysis, over a median follow-up of 3.8 years, α1m and ß2m had positive associations with composite CVD events and mortality, whereas uromodulin had an inverse association with risk for both outcomes. In multivariable analysis including eGFR and albuminuria, a two-fold higher baseline concentration of α1m was associated with higher risk of CVD [hazard ratio (HR) 1.25; 95% confidence interval (CI): 1.10-1.45] and mortality (HR 1.25; 95% CI: 1.10-1.46), whereas ß2m had no association with either outcome. A two-fold higher uromodulin concentration was associated with lower CVD risk (HR 0.79; 95% CI: 0.68-0.90) but not mortality (HR 0.86; 95% CI: 0.73-1.01) after adjusting for similar confounders. CONCLUSION: Among non-diabetic persons with CKD, biomarkers of tubular function are associated with CVD events and mortality independent of glomerular function and albuminuria.

Urinary Biomarkers of Tubular Damage Are Associated with Mortality but Not Cardiovascular Risk among Systolic Blood Pressure Intervention Trial Participants with Chronic Kidney Disease.

BACKGROUND: Kidney tubulointerstitial fibrosis on biopsy is a strong predictor of chronic kidney disease (CKD) progression, and CKD is associated with elevated risk of cardiovascular disease (CVD). Tubular health is poorly quantified by traditional kidney function measures, including estimated glomerular filtration rate (eGFR) and albuminuria. We hypothesized that urinary biomarkers of tubular injury, inflammation, and repair would be associated with higher risk of CVD and mortality in persons with CKD. METHODS: We measured urinary concentrations of interleukin-18 (IL-18), kidney injury molecule-1, neutrophil gelatinase-associated lipocalin, monocyte chemoattractant protein-1, and chitinase-3-like protein-1 (YKL-40) at baseline among 2,377 participants of the Systolic Blood Pressure Intervention Trial who had an eGFR < 60 mL/min/1.73 m2. We used Cox proportional hazards models to evaluate biomarker associations with CVD events and all-cause mortality. RESULTS: At baseline, the mean age of participants was 72 ± 9 years, and eGFR was 48 ± 11 mL/min/1.73 m2. Over a median follow-up of 3.8 years, 305 CVD events (3.6% per year) and 233 all-cause deaths (2.6% per year) occurred. After multivariable adjustment including eGFR, albuminuria, and urinary creatinine, none of the biomarkers showed statistically significant associations with CVD risk. Urinary IL-18 (hazard ratio [HR] per 2-fold higher value, 1.14; 95% CI 1.01-1.29) and YKL-40 (HR per 2-fold higher value, 1.08; 95% CI 1.02-1.14) concentrations were each incrementally associated with higher mortality risk. Associations were similar when stratified by randomized blood pressure arm. CONCLUSIONS: Among hypertensive trial participants with CKD, higher urinary IL-18 and YKL-40 were associated with higher risk of mortality, but not CVD.

Risk of Hospitalization for Cardiovascular Events with ß-Blockers in Hypertensive Patients: A Retrospective Cohort Study.

INTRODUCTION: ß-Blockers are a heterogenous class of drugs that are no longer recommended for initial antihypertension monotherapy due to unfavorable long-term cardiovascular events observed with non-vasodilatory ß-blockers. However, the comparative cardiovascular event risk between the vasodilatory ß1-selective antagonist/ß3 agonist nebivolol and non-vasodilatory ß1-blockers, atenolol and metoprolol, is unknown. METHODS: Incident nebivolol, atenolol, or metoprolol monotherapy users with hypertension were identified using US claims data (2007-2014). The first ß-blocker claim on/after 1/1/2008 defined the index drug/date. Hypertensive patients without pre-index cardiovascular history were followed until index drug discontinuation (> 90 day supply gap), use of other ß-blockers, or end of continuous plan enrollment. Patients were pair-wise propensity score-matched using logistic regression, adjusted for baseline demographics, Charlson Comorbidity Index score, comorbid chronic pulmonary disease, rheumatic disease, renal disease, and diabetes, and use of other antihypertensive drugs during baseline. Time to first hospital claim for a cardiovascular event was assessed via Cox proportional hazards regression, adjusted for the variables above. RESULTS: Inclusion criteria were met by 81,402 patients (n = 27,134 in each matched treatment cohort), with no between-cohort differences in baseline characteristics, comorbid conditions, or average follow-up duration. Atenolol and metoprolol cohorts had greater risk of hospitalization for a composite event (myocardial infarction, angina, congestive heart failure, stroke) than nebivolol users (adjusted hazard ratios [95% confidence interval] atenolol: 1.68 [1.29, 2.17]; metoprolol: 2.05 [1.59, 2.63]; P < 0.001, both). Risks of most individual cardiovascular events were also lower with nebivolol, including myocardial infarction and angina versus atenolol, and myocardial infarction, congestive heart failure, and angina versus metoprolol (P < 0.05, all). CONCLUSIONS: Nebivolol was associated with significantly lower risk of hospitalization due to composite cardiovascular events than atenolol or metoprolol in this large retrospective cohort study of monotherapy with three different ß1-selective blockers in hypertensive patients. FUNDING: Allergan plc, Madison, NJ, USA.

Additivity of nebivolol/valsartan single-pill combinations versus other single-pill combinations for hypertension.

The single-pill combination (SPC) comprising nebivolol (5 mg), a vasodilatory ß1 -selective antagonist/ß3 -agonist, and valsartan (80 mg), a renin-angiotensin-aldosterone system inhibitor, is the only Food and Drug Administration-approved ß-blocker/renin-angiotensin-aldosterone system inhibitor SPC for hypertension. Additive effects of four nebivolol/valsartan SPC doses (5 mg/80 mg, 5/160 mg, 10/160 mg, 10/320 mg nebivolol/valsartan) were compared with five Food and Drug Administration-approved non-ß-blocker/renin-angiotensin-aldosterone system inhibitor SPCs (aliskiren/hydrochlorothiazide, aliskiren/amlodipine, valsartan/amlodipine, aliskiren/valsartan, and telmisartan/amlodipine). Additivity is the ratio of placebo-adjusted SPC blood pressure (BP) reduction to the placebo-adjusted monotherapy component BP reduction sums. A weighted average of comparator scores was calculated and compared vs nebivolol/valsartan. Additivity ratio scores for nebivolol/valsartan SPCs (diastolic BP range: 0.735-0.866; systolic BP range: 0.717-0.822) were similar to the comparator weighted average (diastolic BP: 0.837; systolic BP: 0.825). Among the nebivolol/valsartan SPCs, 5/80 mg had the greatest additivity (diastolic BP: 0.866; systolic BP: 0.822). BP reduction contributions with monotherapy were similar for nebivolol/valsartan 5/80 mg SPC. Additivity scores for nebivolol/valsartan and select non-ß-blocker/renin-angiotensin-aldosterone system inhibitor SPCs were comparable.

Effect of Febuxostat on Ambulatory Blood Pressure in Subjects With Hyperuricemia and Hypertension: A Phase 2 Randomized Placebo-Controlled Study.

BACKGROUND: Hyperuricemia is associated with hypertension, with elevated serum uric acid levels postulated to have a causal role in the development of hypertension. Consequently, serum uric acid reduction may help lower blood pressure (BP). A Phase 2, double-blind, placebo-controlled trial was conducted to assess the potential BP-lowering effects of the xanthine oxidase inhibitor febuxostat in subjects with hypertension and hyperuricemia (serum uric acid ≥0.42 mmol/L [≥7.0 mg/dL]). METHODS AND RESULTS: Subjects (n=121) were randomized 1:1 to febuxostat 80 mg once daily or to placebo. The primary end point was change from baseline to Week 6 in 24-hour mean ambulatory systolic BP (SBP). Additional end points included the following: change from baseline to Week 3 in 24-hour mean SBP and changes from baseline to Weeks 3 and 6 in 24-hour mean ambulatory diastolic BP, serum uric acid, mean daytime and nighttime ambulatory SBP/diastolic BP, and clinic SBP/diastolic BP. For the overall study population, there were no significant differences between febuxostat and placebo for changes from baseline to Weeks 3 or 6 in ambulatory, daytime or nighttime, or clinic SBP or diastolic BP. However, in a preplanned subgroup analysis, there was a significant decrease in SBP from baseline to Week 6 in subjects with normal renal function (estimated glomerular filtration rate ≥90 mL/min) treated with febuxostat versus placebo; least squares mean difference, -6.7; 95% confidence interval -13.3 to -0.0; P=0.049. CONCLUSIONS: This study suggests that febuxostat may lower BP in hyperuricemic patients with hypertension and normal renal function; further studies should be conducted to confirm this finding. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01496469.

Baseline blood pressure control in Hispanics: characteristics of Hispanics in the Systolic Blood Pressure Intervention Trial.

The Systolic Blood Pressure Intervention Trial (SPRINT) tested whether a systolic blood pressure (SBP) value <120 mm Hg reduces adverse clinical outcomes compared with the goal of <140 mm Hg. Here the authors describe the baseline characteristics of Hispanic participants in SPRINT. Nondiabetic hypertensive patients 50 years and older with SBP 130-180 mm Hg taking zero to four blood pressure (BP) medications were enrolled from the mainland United States and Puerto Rico. Cross-sectional, bivariate analysis was employed comparing sociodemographic and clinical factors in Hispanics vs non-Hispanics. Multivariable logistic regression models restricted to Hispanics were used to identify factors associated with achieved BP control (SBP <140 mm Hg and diastolic BP <90 mm Hg) at baseline. Eleven percent (n=984) of SPRINT participants were Hispanic; 56% (n=549) of Hispanics were living in Puerto Rico and the remainder were living on the US mainland. Hispanics overall were younger, more often female, less likely to live alone, and more likely to have lower education and be uninsured, although just as likely to be employed compared with non-Hispanics. BP control was not different between Hispanics vs non-Hispanics at baseline. However, a significantly higher percentage of Hispanics on the US mainland (compared with Hispanics in Puerto Rico) had controlled BP. BP control was independently associated with cardiovascular disease history and functional status among Hispanics, specifically those living in Puerto Rico, whereas functional status was the only independent predictor of BP control identified among mainland Hispanics. These findings highlight the diversity of the SPRINT population. It remains to be seen whether factors identified among Hispanics impact intervention goals and subsequent clinical outcomes.