Extracellular Vesicles in Essential Hypertension: Hidden Messengers

PURPOSE OF REVIEW

Hypertension affects about half of all Americans, yet in the vast majority of cases, the factors causing the hypertension cannot be clearly delineated. Developing a more precise understanding of the molecular pathogenesis of HTN and its various phenotypes is therefore a pressing priority. Circulating and urinary extracellular vesicles (EVs) are potential novel candidates as biomarkers and bioactivators in HTN. EVs are a heterogeneous population of small membrane fragments shed from various cell types into various body fluids. As EVs carry protein, RNA, and lipids, they also play a role as effectors and novel cell-to-cell communicators. In this review, we discuss the diagnostic, functional, and regenerative role of EVs in essential HTN and focus on EV protein and RNA cargo as the most extensively studied EV cargo.

RECENT FINDINGS

The field of EVs in HTN is still a young one and earlier studies have not used the novel EV detection tools currently available. More rigor and transparency in EV research are needed. Current data suggest that EVs represent potential novel biomarkers in HTN. EVs correlate with HTN severity and possibly end-organ damage. However, it has yet to be discerned which specific subtype(s) of EV reflects best HTN pathophysiology. Evolving studies are also showing that EVs might be novel regulators in vascular and renal tubular function and also be therapeutic. RNA in EVs has been studied in the context of hypertension, largely in the form of studies of miRNA, which are reviewed herein. Beyond miRNAs, mRNA in urinary EVs changed in response to sodium loading in humans. EVs represent promising novel biomarkers and bioactivators in essential HTN. Novel tools are being developed to apply more rigor in EV research including more in vivo models and translation to humans.

Blood pressure, heart rate, and mortality in chronic obstructive pulmonary disease: the SUMMIT trial

Aims

To characterize the relationship between blood pressure (BP) or heart rate and mortality and morbidity in chronic obstructive pulmonary disease (COPD).

Methods and results

We performed post hoc analysis of baseline BP or heart rate and all-cause mortality and cardiovascular events in the SUMMIT trial. SUMMIT was a randomized double-blind outcome trial of 16 485 participants (65 ± 8 years, 75% male, and 47% active smokers) enrolled at 1368 sites in 43 countries. Participants with moderate COPD with or at risk for cardiovascular disease (CVD) were randomized to placebo, long-acting beta agonist, inhaled corticosteroid, or their combination. All-cause mortality increased in relation to high systolic [≥140 mmHg; hazard ratio (HR) 1.27, 95% confidence interval (CI) 1.12-1.45] or diastolic (≥90 mmHg; HR 1.35, 95% CI 1.14-1.59) BP and low systolic (<120 mmHg; HR 1.36, 95% CI 1.13-1.63) or diastolic (<80 mmHg; HR 1.15, 95% CI 1.00-1.32) BP. Higher heart rates (≥80 per minute; HR 1.39, 95% CI 1.21-1.60) and pulse pressures (≥80 mmHg; HR 1.39, 95% CI 1.07-1.80) were more linearly related to increases in all-cause mortality. The risks of cardiovascular events followed similar patterns to all-cause mortality. Similar findings were observed in subgroups of patients without established CVD.

Conclusion

A 'U-shaped' relationship between BP and all-cause mortality and cardiovascular events exists in patients with COPD and heightened cardiovascular risk. A linear relationship exists between heart rate and all-cause mortality and cardiovascular events in this population. These findings extend the prognostic importance of BP to this growing group of patients and raise concerns that both high and low BP may pose health risks.

Medicare reimbursement policy for ambulatory blood pressure monitoring: A qualitative analysis of public comments to the Centers for Medicare and Medicaid Services

Ambulatory blood pressure monitoring (ABPM) is considered the best means of diagnosing hypertension. However, it is rarely used and is reimbursed only under narrow conditions. We sought to gain insight into the perceived value of ABPM among stakeholders who responded to the Centers for Medicare and Medicaid Services' (CMS) request for comments to inform the first revision of ABPM reimbursement policy in over 15 years. We found that most comments were classifiable in two main themes, current coverage and future coverage. Individuals and institutions representing multiple disciplines and specialties were highly supportive of expanding the current CMS coverage of ABPM, including for a wide range of clinical indications and populations. It is clear from the comments reviewed that there is wide support for expanding CMS coverage for ABPM. Broad support for a change in ABPM reimbursement policy may lead to changes in the way this technology is used in the United States.

Current Status of Angiotensin Receptor Blocker Recalls

Losartan was the ninth most prescribed drug in the United States in 2016, and several other angiotensin-II receptor blockers (ARBs) are widely prescribed. Since July 2018, >2 dozen specific ARB products have been recalled owing to the presence of potentially carcinogenic nitrosamine impurities in selected lots. As is the case with all U.S. drug recalls, the ARB recalls have been voluntary on the part of the companies involved. In April 2019, the Food and Drug Administration categorized marketed ARB products with respect to nitrosamine impurities: (1) not present, (2) to be determined with no prior lots removed from the market (TBD), or (3) to be determined in the context of prior lots having been removed from the market (TBD*). The data were structured as hundreds of rows of products. Owing to the complexity of these data, more than a year into the recalls, it remains difficult for clinicians to understand which ARB products are free of impurities.

Primary Aldosteronism: Practical Approach to Diagnosis and Management

Primary aldosteronism (PA) is the most common form of secondary hypertension. In many cases, somatic mutations in ion channels and pumps within adrenal cells initiate the pathogenesis of PA, and this mechanism might explain why PA is so common and suggests that milder and evolving forms of PA must exist. Compared with primary hypertension, PA causes more end-organ damage and is associated with excess cardiovascular morbidity, including heart failure, stroke, nonfatal myocardial infarction, and atrial fibrillation. Screening is simple and readily available, and targeted therapy improves blood pressure control and mitigates cardiovascular morbidity. Despite these imperatives, screening rates for PA are low, and mineralocorticoid-receptor antagonists are underused for hypertension treatment. After the evidence for the prevalence of PA and its associated cardiovascular morbidity is summarized, a practical approach to PA screening, referral, and management is described. All physicians who treat hypertension should routinely screen appropriate patients for PA.

Human Urinary mRNA as a Biomarker of Cardiovascular Disease

Supplemental Digital Content is available in the text.

Background

mRNA in urine supernatant (US-mRNA) might encode information about renal and cardiorenal pathophysiology, including hypertension. H, whether the US-mRNA transcriptome reflects that of renal tissues and whether changes in renal physiology are detectable using US-mRNA is unknown.

Methods

We compared transcriptomes of human urinary extracellular vesicles and human renal cortex. To avoid similarities attributable to ubiquitously expressed genes, we separately analyzed ubiquitously expressed and highly kidney-enriched genes. To determine whether US-mRNA reflects changes in renal gene expression, we assayed cell-depleted urine for transcription factor activity of mineralocorticoid receptors (MR) using probe-based quantitative polymerase chain reaction. The urine was collected from prehypertensive individuals (n=18) after 4 days on low-sodium diet to stimulate MR activity and again after suppression of MR activity via sodium infusion.

Results

In comparing this US-mRNA and human kidney cortex, expression of 55 highly kidney-enriched genes correlated strongly (r_s=0.82) while 8457 ubiquitously expressed genes correlated moderately (r_s=0.63). Standard renin-angiotensin-aldosterone system phenotyping confirmed the expected response to sodium loading. Cycle threshold values for MR-regulated targets (SCNN1A, SCNN1G, TSC22D3) changed after sodium loading, and MR-regulated targets (SCNN1A, SCNN1G, SGK1, and TSC22D3) correlated significantly with serum aldosterone and inversely with urinary sodium excretion.

Conclusions

RNA-sequencing of urinary extracellular vesicles shows concordance with human kidney. Perturbation in human endocrine signaling (MR activation) was accompanied by changes in mRNA in urine supernatant. Our findings could be useful for individualizing pharmacological therapy in patients with disorders of mineralocorticoid signaling, such as resistant hypertension. More generally, these insights could be used to noninvasively identify putative biomarkers of disordered renal and cardiorenal physiology.

Privacy-Preserving Generative Deep Neural Networks Support Clinical Data Sharing

Supplemental Digital Content is available in the text.

Background:

Data sharing accelerates scientific progress but sharing individual-level data while preserving patient privacy presents a barrier.

Methods and Results:

Using pairs of deep neural networks, we generated simulated, synthetic participants that closely resemble participants of the SPRINT trial (Systolic Blood Pressure Trial). We showed that such paired networks can be trained with differential privacy, a formal privacy framework that limits the likelihood that queries of the synthetic participants’ data could identify a real a participant in the trial. Machine learning predictors built on the synthetic population generalize to the original data set. This finding suggests that the synthetic data can be shared with others, enabling them to perform hypothesis-generating analyses as though they had the original trial data.

Conclusions:

Deep neural networks that generate synthetic participants facilitate secondary analyses and reproducible investigation of clinical data sets by enhancing data sharing while preserving participant privacy.

Hypertension

Recent guidelines on diagnosis and management of high blood pressure (BP) include substantial changes and several new concepts compared with previous guidelines. These are reviewed and their clinical implications are discussed in this article. The goal is to provide a practical reference to assist clinicians with up-to-date management of patients with high BP. Important issues include new diagnostic thresholds, out-of-office BP monitoring, intensified treatment goals, and a different approach to resistant hypertension. Finally, differences among guidelines, the persistent controversies that have led to them, and their implications for clinical practice are discussed.

Personalized Medicine and the Treatment of Hypertension

PURPOSE OF REVIEW

The purpose of this review is to discuss the implications of personalized medicine for the treatment of hypertension, including resistant hypertension.

RECENT FINDINGS

We suggest a framework for the personalized treatment of hypertension based on the concept of a trade-off between simplicity and personalization. This framework is based on treatment strategies classified as low, medium, or high information burden personalization approaches. The extent to which a higher information burden is justified depends on the clinical scenario, particularly the ease with which the blood pressure can be controlled. A one-size-fits-many treatment strategy for hypertension is efficacious for most people; however, a more personalized approach could be useful in patients with subtypes of hypertension that do not respond as expected to treatment. Clinicians seeing patients with unusual hypertension phenotypes should be familiar with emerging trends in personalized treatment of hypertension.

Clinical research using extracellular vesicles: insights from the International Society for Extracellular Vesicles 2018 Annual Meeting

The abstracts presented at the 2018 International Society for Extracellular Vesicles Annual Meeting offer unique insight into the newest discoveries related to the biology and applied use of extracellular vesicles (EVs). As an extension of a recent "Clinical-Wrap Up" discussion at the International Society for Extracellular Vesicles 2018 Annual Meeting, a systematic review of each abstract was performed to determine which abstracts could be considered clinical research. Once the clinical research abstracts were identified, systematic data extraction included: the major focus of each clinical research abstract; the countries in which the work was done; and the sample size, if provided in the abstract. Each abstract was reviewed by two independent authors, with a third author resolving discrepancies in cases of disagreement. 174 out of 656 (27%) unique abstracts were determined to be clinical research. Oncology was a principal research focus (51 of the 174 clinical research abstracts, 29%). Many other clinical research abstracts presented at the International Society for Extracellular Vesicles 2018 Annual Meeting focused on the use of human samples for development of methods for potential application in the clinic. Beyond oncology and methods development, a wide range of topics was represented, including cardiovascular disease, neurodegenerative disease, genetics, and many others. Current research involving EVs highlights the common, but false dichotomy of science into curiosity-driven basic science or application-driven clinical research, when in fact both quest for understanding and intent to apply the findings appeared to drive much of the work at the International Society for Extracellular Vesicles 2018 Annual Meeting. Using Pasteur's Quadrant as a framework, we discuss where the field of EV research is heading and how we may gain insight into the biological function of EVs in tandem with how they may benefit individual health.

Use of physician-recommended non-pharmacological strategies for hypertension control among hypertensive patients

This study aims to evaluate the 4 non-pharmacological strategies adopted by patients for hypertension control and patient characteristics that affect the choice of strategies. Four thousand hypertensive patients aged ≥18 years were selected from the National Health and Nutrition Examination Survey. Odds ratios of the choice of strategies were analyzed using weighted logistic models. Clinical recommendations of non-pharmacological strategies for hypertension control were relatively low. More exercise was the least frequent strategy used for hypertension control. More patients reported using ≥3 strategies than using ≤2 strategies (79.1% vs 20.9%, P < .0001). Non-Hispanic blacks were more likely to use each individual strategy and to use ≥3 strategies simultaneously. Patients with obesity and diabetes were less likely to attempt weight control or more exercise, but more likely to use ≥3 strategies than peers. Educational programs should be developed to enhance physician's advice for lifestyle modifications and to increase patient's acceptance of physical activity.

Reach Out Churches: A Community-Based Participatory Research Pilot Trial to Assess the Feasibility of a Mobile Health Technology Intervention to Reduce Blood Pressure Among African Americans

Innovative strategies are needed to reduce the hypertension epidemic among African Americans. Reach Out was a faith-collaborative, mobile health, randomized, pilot intervention trial of four mobile health components to reduce high blood pressure (BP) compared to usual care. It was designed and tested within a community-based participatory research framework among African Americans recruited and randomized from churches in Flint, Michigan. The purpose of this pilot study was to assess the feasibility of the Reach Out processes. Feasibility was assessed by willingness to consent (acceptance of randomization), proportion of weeks participants texted their BP readings (intervention use), number lost to follow-up (retention), and responses to postintervention surveys and focus groups (acceptance of intervention). Of the 425 church members who underwent BP screening, 94 enrolled in the study and 73 (78%) completed the 6-month outcome assessment. Median age was 58 years, and 79% were women. Participants responded with their BPs on an average of 13.7 (SD = 10.7) weeks out of 26 weeks that the BP prompts were sent. All participants reported satisfaction with the intervention. Reach Out, a faith-collaborative, mobile health intervention was feasible. Further study of the efficacy of the intervention and additional mobile health strategies should be considered.

Cigarette Smoking and Subtypes of Uncontrolled Blood Pressure Among Diagnosed Hypertensive Patients: Paradoxical Associations and Implications

BACKGROUND

Isolated uncontrolled systolic blood pressure (SBP), uncontrolled systolic-diastolic blood pressure (BP), and isolated uncontrolled diastolic blood pressure (DBP) are subtypes of uncontrolled BP. The associations of smoking with uncontrolled BP subtypes among diagnosed hypertensive patients are unknown.

METHODS

Seven thousand eight hundred twenty-nine subjects aged 18 years or over with diagnosed hypertension were selected from the National Health and Nutrition Examination Survey with stratified multistage clustered sampling design. Weighted logistic regressions were conducted to estimate odds ratios (ORs) with 95% confidence intervals (CIs) of uncontrolled BP subtypes related to smoking status. Weighted multiple regression models were used to examine the association of smoking with levels of SBP, DBP, and pulse pressure.

RESULTS

The average age of the study sample was 60.3 ± 0.3 years. 54.2% ± 0.7% were females. Compared to nonsmokers, current smokers were 22% less likely to have uncontrolled BP (OR: 0.78, 95% CI: 0.64-0.94, P = 0.01), and 21% less likely to have isolated uncontrolled SBP (OR: 0.79, 95% CI: 0.64-0.97, P = 0.02). Average DBP was 1.5 mm Hg lower (95% CI: -2.8 to -0.2 mm Hg, P = 0.02) in current smokers than in nonsmokers. Average DBP was 0.9 mm Hg lower (95% CI: -1.7 to -0.03 mm Hg, P = 0.04) in former smokers than in nonsmokers. Current smoking and former smoking were not associated with risk of uncontrolled systolic-diastolic BP and isolated uncontrolled DBP.

CONCLUSIONS

Paradoxical associations between current smoking and SBP, uncontrolled BP and isolated uncontrolled SBP were shown among hypertensive patients. The explanation for these associations is currently unknown. No cause-effect relationships should be assumed.

Personalized medicine and treatment approaches in hypertension: current perspectives

In the US, hypertension affects one in three adults. Current guideline-based treatment of hypertension involves little diagnostic testing. A more personalized approach to the treatment of hypertension might be of use. Several methods of personalized treatment have been proposed and vetted to varying degrees. The purpose of this narrative review is to discuss the rationale for personalized therapy in hypertension, barriers to its development and implementation, some influential examples of proposed personalization measures, and a view of future efforts.

Anxiety in the "age of hypertension"

In the USA, hypertension affects one in three adults, and anxiety disorders are the most commonly diagnosed mental health disorders. Both hypertension and anxiety have been studied extensively. Yet, a full understanding of anxiety's relationship to hypertension has been elusive. In this review, we discuss the spectrum of anxiety disorders. In addition, we consider the evidence for acute and long-term effects of anxiety on blood pressure. We review the effect on blood pressure of several "real-world" stressors, such as natural disasters. In addition, we review the effect of anxiety treatments on blood pressure. We explain the American Heart Association's recent recommendations regarding meditation and other relaxation methods in the management of hypertension. We conclude that novel research methods are needed in order to better elucidate many aspects of how anxiety relates to hypertension.