Metabolomics Signature of Plasma Renin Activity and Linkage with Blood Pressure Response to Beta Blockers and Thiazide Diuretics in Hypertensive European American Patients

Plasma renin activity (PRA) is a predictive biomarker of blood pressure (BP) response to antihypertensives in European–American hypertensive patients. We aimed to identify the metabolic signatures of baseline PRA and the linkages with BP response to β-blockers and thiazides. Using data from the Pharmacogenomic Evaluation of Antihypertensive Responses-2 (PEAR-2) trial, multivariable linear regression adjusting for age, sex and baseline systolic-BP (SBP) was performed on European–American individuals treated with metoprolol (n = 198) and chlorthalidone (n = 181), to test associations between 856 metabolites and baseline PRA. Metabolites with a false discovery rate (FDR) < 0.05 or p < 0.01 were tested for replication in 463 European–American individuals treated with atenolol or hydrochlorothiazide. Replicated metabolites were then tested for validation based on the directionality of association with BP response. Sixty-three metabolites were associated with baseline PRA, of which nine, including six lipids, were replicated. Of those replicated, two metabolites associated with higher baseline PRA were validated: caprate was associated with greater metoprolol SBP response (β = −1.7 ± 0.6, p = 0.006) and sphingosine-1-phosphate was associated with reduced hydrochlorothiazide SBP response (β = 7.6 ± 2.8, p = 0.007). These metabolites are clustered with metabolites involved in sphingolipid, phospholipid, and purine metabolic pathways. The identified metabolic signatures provide insights into the mechanisms underlying BP response.

Global REACH 2018: Volume regulation in high-altitude Andeans with and without chronic mountain sickness

The high-altitude maladaptation syndrome known as chronic mountain sickness (CMS) is characterized by polycythemia and is associated with proteinuria despite unaltered glomerular filtration rate. However, it remains unclear if indigenous highlanders with CMS have altered volume regulatory hormones. We assessed N-terminal pro-B-type natriuretic peptide (NT pro-BNP), plasma aldosterone concentration, plasma renin activity, kidney function (urinary microalbumin, glomerular filtration rate), blood volume, and estimated pulmonary artery systolic pressure (ePASP), in Andean males without (n=14; age=39±11) and with (n=10; age=40±12) CMS at 4330 meters (Cerro de Pasco, Peru). Plasma renin activity (non-CMS: 15.8±7.9 vs. CMS: 8.7±5.4 ng/ml; p=0.025) and plasma aldosterone concentration (non-CMS: 77.5±35.5 vs. CMS: 54.2±28.9 pg/ml; p=0.018) were lower in highlanders with CMS compared to non-CMS, while NT pro-BNP was not different between groups (non-CMS: 1394.9±214.3 vs. CMS: 1451.1±327.8 pg/ml; p=0.15). Highlanders had similar total blood volume (non-CMS: 90±15 vs. CMS: 103±18 ml • kg-1; p=0.071), but Andeans with CMS had greater total red blood cell volume (non-CMS: 46±10 vs. CMS 66±14 ml • kg-1; p<0.01) and smaller plasma volume (non-CMS 43±7 vs. CMS 35±5 ml • kg-1; p=0.03) compared to non-CMS. There were no differences in ePASP between groups (non-CMS 32±9 vs. CMS 31±8 mmHg; p=0.6). A negative correlation was found between plasma renin activity and glomerular filtration rate in both groups (group: r=-0.66; p<0.01; non-CMS: r=-0.60; p=0.022; CMS: r=-0.63; p=0.049). A smaller plasma volume in Andeans with CMS may indicate an additional CMS maladaptation to high-altitude, causing potentially greater polycythemia and clinical symptoms.

Descending thoracic aorta–abdominal aortic bypass and bilateral renal arterial blood circulation reconstruction are effective in atypical coarctation of the aorta with heart failure: a case report

Background There are a lot of reports of the renal failure and heart failure due to coarctation of the aorta. However, there are no case reports in which revascularization dramatically improved left ventricular function in patients with progressive decline in left ventricular function. Herein, we present a rare case in which the left ventricular function was dramatically improved by surgical treatment for progressive left ventricular dysfunction due to atypical coarctation of the aorta. Case presentation A 58-year-old man underwent left axillary artery-bilateral femoral artery bypass at another hospital for atypical coarctation of the aorta due to Takayasu’s arteritis. Approximately 10 years later, he was re-hospitalized for heart failure, and the left ventricular ejection fraction gradually decreased to 28%. Computed tomography showed severe calcification and stenosis at the same site from the peripheral thoracic descending aorta to the lower abdominal aorta of the renal artery, and aortography showed delayed bilateral renal artery blood flow. An increase in plasma renin activity was also observed. Despite the administration of multiple antihypertensive drugs, blood pressure control was insufficient. We decided to perform surgical treatment to improve progressive cardiac dysfunction due to increased afterload and activated plasma renin activity. Descending thoracic aorta-abdominal aorta bypass and revascularization of the bilateral renal arteries via the great saphenous vein grafts were performed. Postoperative blood pressure control was improved, and the dose of antihypertensive drugs could be reduced. Plasma renin activity decreased, and transthoracic echocardiography 1.5 years later showed an improvement in contractility with a left ventricular ejection fraction of 58%. Conclusion In atypical coarctation of the aorta in patients with decreased bilateral renal blood flow, heart failure due to renal hypertension, and progressive decrease in left ventricular contractility, descending thoracic aorta-abdominal aortic bypass and bilateral renal artery recirculation can be extremely effective.

Descending Thoracic Aorta–abdominal Aortic Bypass and Bilateral Renal Arterial Blood Circulation Reconstruction Are Effective in Atypical Coarctation of the Aorta With Heart Failure: a Case Report

Background: There are many reports on renal failure and heart failure due to coarctation of the aorta. However, there are no case reports in which revascularization dramatically improved left ventricular function in patients with progressive decline in left ventricular function. Herein, we present a rare case in which the left ventricular function dramatically improved after surgical treatment in a patient with progressive left ventricular dysfunction due to atypical coarctation of the aorta.Case presentation: A 58-year-old man underwent axilobifemoral bypass at another hospital for atypical coarctation of the aorta due to Takayasu’s arteritis. Approximately 10 years later, he was re-hospitalized for heart failure, and his left ventricular ejection fraction gradually decreased to 28%. Computed tomography showed severe calcification and stenosis at the same site from the peripheral thoracic descending aorta to the lower abdominal aorta up to the renal arteries, and aortography showed delayed bilateral renal artery blood flow. An increase in plasma renin activity was also observed. Despite the administration of multiple antihypertensive drugs, blood pressure control was insufficient. We decided to perform surgical treatment to improve progressive cardiac dysfunction due to increased afterload and activated plasma renin activity. Descending thoracic aorta–abdominal aorta bypass and revascularization of both renal arteries via a great saphenous vein grafts were performed. Postoperative blood pressure control improved, and the dose of antihypertensive drugs could be reduced. Plasma renin activity decreased, and transthoracic echocardiography performed 1.5 years later showed improvement in contractility with a left ventricular ejection fraction of 58%. Conclusion: In patients with atypical coarctation of the aorta and decreased bilateral renal blood flow, heart failure due to renal hypertension, and progressive decrease in left ventricular contractility, descending thoracic aorta–abdominal aortic bypass and bilateral renal artery recirculation can be extremely effective.

High plasma renin activity associates with obesity-related diabetes and arterial hypertension, and predicts persistent hypertension after bariatric surgery

Background Information about the renin–angiotensin–aldosterone system (RAAS) in obese individuals before and after bariatric surgery is scarce. Aim of this study was to analyze the RAAS in severely obese subjects, in relation to anthropometric and metabolic variables, with special reference to glucose tolerance. Methods 239 subjects were evaluated at baseline, and 181 one year after bariatric surgery [laparoscopic gastric banding (LAGB)]. Results At baseline, renin (plasma renin activity, PRA) was increased from normal to glucose tolerance and more in diabetes, also correlating with ferritin. After LAGB, the decrease of PRA and aldosterone was significant in hypertensive, but not in normotensive subjects, and correlatied with decrease of ferritin. PRA and glucose levels were predictive of persistent hypertension 1 year after LAGB. Conclusions These data support the role of RAAS in the pathophysiology of glucose homeostasis, and in the regulation of blood pressure in obesity. Ferritin, as a proxy of subclinical inflammation, could be another factor contributing to the cross-talk between RAAS and glucose metabolism.

Plasma Renin Activity after Diuretic Treatment in Patients with Stable Heart Failure: With Special Reference to its Association with Electrolyte Chloride

A recent study reported an intimate association between urinary chloride (Cl) and plasma renin activity (PRA) in acute heart failure (HF) status, reflecting normal functioning of the ‘tubulo-glomerular feedback’ mechanism. Whether the ‘tubuloglomerular feedback’ mechanism functions normally in stable HF status, however, is unclear. This study examined whether the ‘tubulo-glomerular feedback’ mechanism functions normally under resolution of worsening HF after decongestive therapy. Data from 26 patients with acute HF and its recovery after decongestive therapy were analyzed. Clinical tests included measurement of peripheral blood tests, serum and spot urinary electrolytes, plasma neurohormones, and fractional urinary excretions of electrolytes. In a total of 26 patients, PRA increased after acute HF treatment (from 1.64±2.0 to 5.48±6.1 ng/ mL/h, p=0.002). Changes in the serum logPRA and urinary Cl concentration from worsening to its recovery tended to be inversely correlated (R2 =0.12, p=0.085) and logPRA and the serum Cl concentration at recovery were inversely correlated (R2 =0.23, p=0.01). When divided into 2 groups (n=13 in each) according to the median PRA, the group with greater PRA changes showed a larger decrease in the urinary Cl concentration (from 110±44 to 72.8±38, p=0.03). The group with higher PRA at recovery showed a lower serum Cl concentration than the group with lower PRA at recovery (102±6.5 vs 107±4.2 mEq/L, p=0.04). In conclusion, the association between PRA and the serum/urinary Cl concentration is blunted in stable HF under-decongestive therapy, possibly due to the physiologic status under full cardiovascular medication compared with that in acute HF status.

125 Increased plasma renin activity during wake in a repetitive sleep restriction protocol

Introduction Insufficient sleep is associated with an increased risk of hypertension. It is well established that long-term BP regulation is modulated by the renin-angiotensin-aldosterone system (RAAS) and chronic kidney disease is a strong independent risk factor for development of cardiovascular disease. This study investigated the biomarkers of RAAS and renal function during repetitive exposures to controlled, experimental sleep restriction (SR). We hypothesized an upregulation of RAAS and increased markers of impaired renal function. Methods Twenty-one healthy participants (11 women, average age 31±2 years) completed the 22-day in-hospital SR protocol: permitted 4h of sleep/night from 0300-0700 for 3 nights followed by a recovery sleep, repeated 4 times. Blood samples were collected and plasma renin activity (PRA) was assessed in the morning (7:05am) and in the evening before bedtime (22:45pm) at baseline, experimental days (3rd day of each of the 4 blocks), and recovery. Urinary albumin to creatinine ratio (ACR) was measured from 24-h urinary collection at baseline, first and fourth SR blocks. Estimated glomerulus filtration rate (eGFR) was calculated based on the serum cystatin C levels at baseline and last block of SR. Results Percent change of evening PRA significantly increased during 4 blocks of SR and recovery (SR effect p=0.039), but not morning PRA (SR effect p=0.34). Specifically, evening PRA increased up to 98.4% in the first (p&lt;0.01), 61.3% in the second (p=0.04) SR blocks, and 57.5% (p=0.05) in recovery. Urinary ACR showed no significant changes during first or fourth SR blocks (SR effect p=0.28). In addition, eGFR did not change in the fourth SR block compared to BL (paired t-test, p=0.27). Conclusion We did not see increased markers of impaired renal function (ACR or eGFR). Rather, short-term repetitive exposures to SR significantly increased percent change of PRA measured before bedtime, and evening PRA did not return to BL level during recovery. Our results suggested that sleep deficiency may contribute to hypertension through upregulation of RAAS during wake time. Support (if any) SRSF (CDA to Huan Yang), NIH (R01HL106782 to Dr. Janet Mullington), Harvard Catalyst, Harvard Clinical and Translational Science Center (UL1TR001102).

Aldosterone/Direct Renin Concentration Ratio Versus Aldosterone/Plasma Renin Activity for Diagnosis of Primary Hyperaldosteronism: Case Presentation

Aldosterone/Direct Renin concentration ratio versus Aldosterone/Plasma renin activity for diagnosis of Primary Hyperaldosteronism: Case presentation. Introduction: Primary hyperaldosteronism (PA) is the most common cause of secondary hypertension. Endocrine Society guidelines recommend using aldosterone-to-renin ratio (ARR) for screening of PA1. This ratio can be obtained using two different methods. The first is plasma aldosterone concentration (PAC) divided by plasma renin activity. ARR greater than 20 is suggestive of PA. Further testing is required for confirmation. Due to limitations and challenges in obtaining PRA, another method of measurement was developed in which the direct renin concentration (DRC) is measured. There have been inconsistent recommendations regarding what ratio is appropriate using this assay to diagnose hyperaldosteronism. The aim of this case presentation is to review a patient with PA in whom both measurement methods were used and compared for screening. Case Presentation: A 45-year woman with past medical history of Graves’ disease and hypertension presented with hypokalemia. Blood pressure was well-controlled on amlodopine for 3 years. PAC and DRC were measured. PAC was 21.2 ng/dL and DRC 2.8 pg/ml with ARR 7.6. This was repeated and confirmed (PAC 19.6 ng/dL and DRC 3.9 pg/ml with ARR 5). Plasma Renin Activity (PRA) was measured. PAC was 36.3 ng/dL and PRA was 0.19 ng/ml/hr (ARR 191), suggestive of hyperaldosteronism. Further workup including a CT scan of the abdomen with IV and oral contrast demonstrated an enhancing 1.8 cm nodule in the left adrenal gland. Adrenal vein sampling was performed. Left adrenal vein aldosterone level was 1400 ng/dl and on the right, 33.1 ng/dl. The patient was treated with left laparoscopic adrenalectomy. The pathological evaluation of the specimen demonstrated a 2.5 cm adenoma of benign etiology. Later follow-up showed the patient was normokalemic with PAC of 3.1. Conclusion: Patients with PA despite controlled hypertension, experience higher rates of cardiovascular events, hence early and accurate diagnosis is essential. PRA measurement has multiple limitations including inter-laboratory variations, higher cost, availability in only advanced laboratories and values influenced by blood pressure medications. Therefore, some institutions have replaced it with direct renin concentration (DRC) which is cheaper and more widely available. DRC has limitations with fewer positive ARR results. When the clinical suspicion is high, PRA is the more precise study to calculate ARR. The Management of Primary Aldosteronism: Case Detection, Diagnosis, and Treatment: An Endocrine Society Clinical Practice Guideline. John W. Funder, Robert M. Carey, Franco Mantero, et al. The Journal of Clinical Endocrinology & Metabolism, Volume 101, Issue 5, 1 May 2016, Pages 1889–1916, https://doi.org/10.1210/jc.2015–4061.