Renin Levels In Patients Research Articles

Plasma renin as a novel prognostic biomarker of sepsis-associated acute respiratory distress syndrome

Sepsis-associated acute respiratory distress syndrome (ARDS) is a life-threatening condition in critical care medicine for which there is a substantial need for early prognostic biomarkers of outcome. The present study seeks to link plasma renin levels and 30-day mortality in sepsis-associated ARDS patients treated at our institution. The Registry of Critical Illness (RoCI) prospectively enrolled patients from the intensive care units (ICU) within a single academic medical center, and a convenience sample of patients with sepsis-associated ARDS was analyzed from this cohort. This study was approved by the Mass General Brigham Institutional Review Boards (IRB) as part of the RoCI, and all procedures performed were in accordance with the ethical standards of the institutional board. From April 2012 to February 2019, a cohort of 32 adult sepsis-associated ARDS patients with 500 µL of plasma samples available on Day 0 and Day 3 of their ICU stay were enrolled. Renin levels were measured twice, on Day 0 and Day 3 via the direct renin enzyme-linked immunosorbent assay (ELISA EIA-525) by DRG diagnostics. Day 0 and Day 3 renin were statistically evaluated via logistic regression to predict 30-day mortality. Direct renin levels of 64 samples were assayed from 32 sepsis-associated ARDS patients (50% male; mean ± SD, 55 ± 13.8 years old). The 30-day hospital mortality rate was 59.4%. Patients who died within 30 days of admission were more likely to have an elevated Day 3 Renin (Odds ratio [OR] = 6, 95% CI 1.25–28.84) and have received vasopressors (OR = 13.33, 95% CI 1.43–123.95). Adjusting for vasopressor use as a proxy for septic shock status, patients with an Elevated Day 3 Renin had a 6.85 (95% CI 1.07–43.75) greater odds of death than those with Low-Normal Day 3 Renin. Patients with sustained Elevated Renin levels from Day 0 to Day 3 had the highest risk of death in a 30-day window. In this study, we found that renin may be a novel biomarker that has prognostic value for patients with sepsis-associated ARDS. Future studies evaluating renin levels in patients with sepsis-associated ARDS are needed to validate these findings.

RAS-challenge as a first-look test for detection of primary aldosteronism in patients with treatment-resistant hypertension

Purpose Primary aldosteronism (PA), characterised by low-renin hypertension, confers a high cardiovascular risk and is the most common cause of secondary hypertension, with an increased prevalence in patients with treatment-resistant hypertension. However, it is estimated that only a small percentage of affected patients are identified in routine clinical practice. Inhibitors of the renin-angiotensin system cause an increase in renin levels in patients with intact aldosterone regulation, and inadequate low renin with concurrent RAS inhibition (RASi) may therefore indicate PA, which could serve as a first look screening test for selection for formal work-up. Methods We analysed patients between 2016–2018 with treatment-resistant hypertension who had inadequate low renin in the presence of RASi (i. e. at risk for PA) and who were offered systematic work-up with adrenal vein sampling (AVS). Results A total of 26 pts were included in the study (age 54.8 ± 11, male 65%). Mean office blood pressure (BP) was 154/95 mmHg on 4.5 antihypertensive drug classes. AVS had a high technical success rate (96%) and demonstrated unilateral disease in the majority of patients (57%), most of which (77%) were undetected by cross-sectional imaging. Conclusion In patients with resistant hypertension, low renin in the presence of RASi is a strong indicator for autonomous aldosterone secretion. It may serve as an on-medication screening test for PA to select for formal PA work up.

Hypokalemia and the renin-angiotensinaldosterone system activity in COVID-19 patients

Background. Hypokalemia is a common electrolyte complication among hospitalized patients with pneumonia caused by a new coronavirus SARS-CoV-2. Hyperactivation of the renin-angiotensin-aldosterone system (RAAS) is suggested as a possible cause of hypokalemia in patients with COVID-19.Objective. To investigate the RAAS activity in COVID-19 patients with and without hypokalemia and its possible association with treatment outcomes.Design and methods. The cross-sectional cohort study included 172 patients with COVID-19 pneumonia. Potassium, aldosterone and venous renin were measured in 77 patients. The differences in the levels of acute phase proteins, the degree of lung damage and the severity of COVID-19 were compared between patients with and without hypokalemia.Results. Hypokalemia was found in 19 of 77 patients (25%): the median potassium level in hypokalemia and eukalemia group was 3,1 [2,8–3,3] and 4,1 [3,9–4,5] mmol/L, respectively (p = 0,001). Plasma aldosterone and renin levels in patients with and without hypokalemia did not differ significantly: aldosterone 76,0 [57,7–121,5] and 70,9 [26,3–113,8] pg/ml (p = 0,23), renin 17,0 [8,5–47,2] and 11,0 [6,5–38,1] pg/ml (p = 0,35), respectively. Differences in the degree of lung tissue damage, acute phase proteins, severity of COVID-19, length of hospitalization and mortality in patients with and without identified electrolyte disturbances were also not significant.Conclusions. Our results showed that there were no laboratory signs of RAAS hyperactivation in COVID-19 patients with registered hypokalemia. Identification of the cause and clinical significance of hypokalemia among patients with COVID-19 needs to be specified.

SAT-564 Effectiveness of Treatment with Mineralocorticoid Receptor Antagonistsin Primary Aldosteronism

Background: Medical treatment with mineralocorticoid receptor antagonists (MRAs) is preferred for patients with primary aldosteronism (PA) who are not surgical candidates. Adequate mineralocorticoid receptor blockade, as suggested by renin elevation above suppression levels, has been associated with lower rates of cardiovascular and renal complications as compared with PA with sustained renin suppression. Objectives: To assess the timeline and rates of achieving target renin levels in patients with PA and low renin hypertension treated with MRAs. Patients and Methods: We conducted a retrospective cohort study of adult patients with hypertension who were treated with MRAs in an academic center between 2003-2019. Of these, we included patients who had suppressed renin at baseline, and repeated renin measurement(s) during MRAs therapy. Renin suppression was defined as plasma renin activity (PRA) 1.0 ng/mL/h or direct renin concentration (DRC) 8.0 pg/mL. We excluded patients with adrenal cancer, end-stage renal disease, exogenous glucocorticoids, and critically ill. Mann-Whitney test, Wilcoxon signed rank test, Chi-Square test and multiple logistic regression analysis were employed, as appropriate. Results: So far, 89 patients (45 men), median age 56 (range, 19-84), have been included. Of these, 46% had confirmed PA; 25% had positive PA screening, but no confirmatory tests; and 29% had other forms of low-renin hypertension. On average, patients were on 2.9 1.6 antihypertensive agents; 62% of patients were prescribed beta blockers, and 38% were on K+ supplements. Overall, renin (PRA in 69 cases, and DRC in 20 cases) increased after MRA treatment (from 0.40 [0.10, 0.60] ng/mL/h to 1.10 [0.60, 2.23] ng/mL/h; and from 2.1 [2.1, 3.7] pg/mL to 5.7 [2.9, 16.7] pg/mL, respectively, p<0.0001 for both). The cumulative proportions of patients in whom renin reached target levels during MRA treatment were: 25% at 2 weeks; 38.9% at 1 month; 34.2% at 3 months; 39.5% at 6 months; and 47.2% at 1 year. Age, sex, race, blood pressure, use of beta blockers, renal function, serum K+ and aldosterone concentrations were similar between patients with target vs. suppressed renin. Multiple logistic regression analysis suggested that after adjusting for age and sex, higher MRA dose and higher BMI were associated with higher likelihood of achieving target renin during MRA therapy (odds ratio (95%CI): 1.021 (1.001-1.041) and 1.097 (1.008-1.193), respectively, p<0.05 for both); conversely, beta blockers use tended to be less often associated with target renin (odds ratio, 0.37 (0.13-1.008), p=0.052). Conclusion: Although raising renin above suppression levels is important for reducing the cardiovascular risk associated with PA, this goal is achieved in less than half of patients, even after one year of treatment with MRAs, in an academic setting. Strategies for optimizing PA treatment are critically needed.

Effect of Vitamin D therapy on urinary albumin excretion, renal functions, and plasma renin among patients with diabetic nephropathy

Background:Despite different management strategies, progression of proteinuria occurs in a sizable category of patients with diabetic nephropathy (DN). Increase in serum renin levels induced by the renin–angiotensin system (RAS) may contribute to this. Vitamin D therapy is found to have an inhibitory effect on the RAS. We aimed to study the effects of Vitamin D therapy on renal functions of patients with DN.Methods:This was a double-blind, randomized, placebo-controlled study. Patients with DN (urinary albumin [UA] >30 mg/g of creatinine) whose estimated glomerular filtration rate (eGFR) was more than 30 mL/min were selected and their plasma renin, parathyroid hormone, serum Vitamin D, serum calcium, serum creatinine, fasting blood sugar were done as baseline measurements. Subjects were randomized into two groups and treatment group was given Vitamin D, 50000 IU (0.25 ml) intramuscularly (IM) monthly for 6 months; control group received distilled water IM. Investigations were repeated after 6 months of therapy.Results:Of 155 patients invited, 85 were randomly assigned to two groups. After 6 months, mean reduction of UA to creatinine ratio in the treatment and control group was 51.8 mg/g (95% confidence interval [CI]; 66.1–−37.5, P ≤ 0.001); 22.4 mg/g (95% CI; −45.7–0.8, P = 0.06), respectively (between group difference P = 0.001). Significant increase in the eGFR observed in the treatment group while eGFR remained unchanged in the control group (P = 0.03 for the between-group difference). Mean reduction in plasma renin in treatment group and control group was 5.85 pg/mL (95% CI; −6.7–−4.6) (P < 0.001) and 0.95 pg/mL (95% CI; −1.4–−0.14, P = 0.02), respectively.Conclusions:Vitamin D 50000 IU given IM monthly for 6 months reduces urine albumin, serum creatinine, and renin levels in patients with DN.

Prorenin cryoactivation as a possible cause of normal renin levels in patients with primary aldosteronism

Prorenin cryoactivation as a possible cause of normal renin levels in patients with primary aldosteronism

Prorenin cryoactivation as a possible cause of normal renin levels in patients with primary aldosteronism

Prorenin cryoactivation as a possible cause of normal renin levels in patients with primary aldosteronism

The Effects of Hormones of the Hypothalamo-Hypophyseal-Adrenal, Renin-Angiotensin, and Thyroid Hormone Systems on the Formation of Dyscirculatory Encephalopathy

Measurements were made of plasma levels of free (f) thyroxine (fT4), triiodothyronine (fT3), thyrotropic hormone (TSH), adrenocorticotrophic hormone (ACTH), aldosterone, and renin in patients with dyscirculatory encephalopathy (DE). Their influences on the development of chronic circulatory insufficiency were assessed. A total of 39 patients were studied (aged 45-73 years) with DE stages I and II, without acute or chronic (in the exacerbation phase) somatic illness. These observations showed that diffuse lesions of brain tissues of different severities were accompanied by the following changes in thyroid homeostasis: 1) significant combined increases in TSH without alteration to the "fT3-TSH" negative feedback regulatory mechanism in patients with stage I DE; 2) significant combined decreases in TSH levels with marked suppression of the conversion of thyroxine into triiodothyronine and an interaction with impairments in the "fT3-hypophysis" system in patients with stage II DE. In addition, there were changes (increases) in cortisol levels with simultaneous decreases in renin levels in patients with stage II DE as compared with patients with stage I DE. Correlation analysis demonstrated the absence of any relationship between the age of the patients, the state of hormonal homeostasis, and the extent of vascular stenosis. These results suggest a role for hormones of the hypothalamo-hypophyseal-adrenal, thyroid, and renin-angiotensin systems in the mechanism by which DE develops as well as the possibility of using tests for these hormones as additional criteria for assessing the severity of diffuse brain lesions.

Circulating vascular endothelial growth factor and active renin concentrations and prostaglandin E2 urinary excretion in patients with adrenal tumours.

The aim of the present study was to determine vascular endothelial growth factor (VEGF), prostaglandin E(2) (PGE(2)) and active renin levels in patients with hormonally active adrenal tumours. The study was comprised of 16 patients with primary aldosteronism, 13 patients with active Cushing's syndrome due to adrenal adenomas, 8 patients with adrenal carcinomas, 19 patients with phaeochromocytoma and 19 healthy volunteers. Active renin in plasma was determined by a two-site immunoradiometric assay. VEGF in sera samples and PGE(2) in 24-h urine were measured by ELISA. VEGF was significantly elevated in all the four groups of patients as compared with the controls. VEGF levels in patients with Cushing's syndrome were higher than those in patients with primary aldosteronism. Patients with adrenal carcinomas had the highest VEGF levels and the differences reached significance as compared with patients with primary aldosteronism and phaeochromocytoma. PGE(2) levels were not significantly different among groups. Active renin was significantly the lowest in patients with primary aldosteronism and significantly the highest in patients with phaeochromocytoma compared with the controls. Active renin in patients with primary aldosteronism was significantly lower than in those with Cushing's syndrome, phaeochromocytoma and adrenal carcinoma. Our data indicated that the mean level of VEGF in patients with all investigated adrenal tumours was significantly higher than in healthy controls. The cortisol-producing tumours appear to have increased angiogenic potential. Angiogenesis is probably associated not only with malignancy but also with functional activity of the adrenal tumors.

The significance of plasma renin levels in patients with dilated cardiomyopathy on therapeutic doses of ACE inhibitor

The significance of plasma renin levels in patients with dilated cardiomyopathy on therapeutic doses of ACE inhibitor

The Significance of Plasma Renin Levels in Patients With Dilated Cardiomyopathy on Therapeutic Doses of ACE Inhibitor

The Significance of Plasma Renin Levels in Patients With Dilated Cardiomyopathy on Therapeutic Doses of ACE Inhibitor

Role of the Circulating and Tissue-Based Renin-Angiotensin System in the Development of Heart Failure: Implications for Therapy

The renin-angiotensin system (RAS) is believed to play a central role in the pathophysiology of heart failure. However, there is a wide variability in plasma renin levels in patients with heart failure, and normal plasma renin activity has been documented in patients with mild or compensated disease. Recent evidence has demonstrated the existence of endogenous RAS in a number of tissues associated with cardiovascular homeostasis. It is possible that these tissue RAS are activated in the early stages of heart failure when plasma renin activity is normal, and therefore contribute to the progression of this condition. Angiotensin-converting enzyme (ACE) inhibitors reduce both circulating and tissue RAS activity. They are of symptomatic benefit and reduce the mortality associated with heart failure. A number of large studies initiated to investigate the effects of the ACE inhibitor enalapril in patients with all degrees of heart failure have been published recently. These studies show that addition of this drug to therapy significantly decreases patient morbidity and mortality, an effect which is most likely due to the suppression of circulating and tissue RAS activity this agent affords. The relationship of the profile of hormonal suppression seen with enalapril and drug dosage to observed beneficial effects on morbidity or mortality is unclear. Given the large range of alternative ACE inhibitors available, their variable structure, potency and duration of action, the potential for differences between agents needs further consideration. Although direct comparative studies are rare, there is a body of work suggesting that such differentiation may be present and may be of clinical significance.

Characterization of a Radioimmunoassay to Determine Plasma Total Renin

The determination of plasma total renin is useful not only as a tool to investigate the physiology of hypertension but also as a marker for Wilms' tumor. A radioimmunoassay (RIA) system to determine plasma total renin was newly developed using monoclonal antibodies specific for both inactive and active renin (inactive + active = total); in this study, an effort was made to confirm that this RIA system truly determines plasma total renin concentrations. First, it was found that this monoclonal antibody stains only the juxtaglomerular apparatus of the kidney. Second, the data determined by the RIA were compared with those obtained by the conventional enzymatic method: samples were activated, and renin activity was assayed by measuring angiotensin I. The coefficient of the data obtained by this RIA system and by the conventional method was 0.921 (p less than 0.01) based on all 89 samples, and 0.809 (p less than 0.01) based on 86 of the 89 samples whose values were less than 600 pg/ml by RIA. As a result of these studies, it was concluded that the newly developed RIA system does determine total renin levels in patients' plasma.

Determination of plasma total renin level by RIA with a monoclonal antibody: Value as a marker for nephroblastoma

Plasma total renin is a new, useful marker for nephroblastoma, but the conventional method for determining its level is sophisticated and requires large blood samples. To develop a simpler technique, a monoclonal antibody specific for both inactive and active renin (inactive + active = total) was raised, and a radioimmunoassay (RIA) system was established. This monoclonal antibody stains only the juxtaglomerular apparatus; values determined by this RIA did not change before and after activation. So far, the RIA system has been applied to 136 samples from 92 patients. Plasma total renin levels were also determined with the conventional method: samples were activated, then renin activity was assayed by measuring angiotensin I. The coefficient of the data obtained by these two different techniques was 0.921 ( P < .01). Plasma total renin levels in patients with nephroblastoma were significantly increased (546.5 ± 297.8 pg/mL) over those in patients with neuroblastoma (218.6 ± 46.5 pg/mL) and in controls (165.8 ± 67.5 pg/mL, P < .01). After removal of Wilms' tumors, the levels decreased to normal when sampled every 2 weeks. It was concluded that a newly developed RIA system is more useful in determining plasma total renin levels in patients with nephroblastoma.

Plasma renin levels in patients with thoracic neuroblastoma

Plasma renin levels are elevated in neuroblastoma as in nephroblastoma patients. Unlike nephroblastoma, the active component appears to predominate. Patients with thoracic neuroblastoma produce high levels of renin by the tumour, which thus excludes an ischaemic aetiology as the source.

The Effects of Aprotinin, a Kallikrein Inhibitor, on Renin Release and Urinary Sodium Excretion in Mild Essential Hypertensives

The effects of aprotinin on renin release and renal function were evaluated in 24 male essential hypertensive patients, on unrestricted (n = 17) and on chronic low as well as on high sodium intake. Aprotinin (1 X 10(6) kallikrein inhibitor units) or saline (200 ml) were infused in all patients for 6 h. Blood samples were taken for plasma renin activity (PRA) and 6-h urine collections were obtained for active and inactive kallikrein, sodium and potassium excretion measurement. In patients on unrestricted sodium diet, aprotinin had no effect on blood pressure (BP), glomerular filtration rate, renal plasma flow, urinary sodium and potassium excretion. However, an inverse relationship was found between pretreatment urinary sodium excretion and the per cent reduction of the latter after aprotinin. A significant reduction in urinary sodium excretion was induced by aprotinin in patients on high sodium intake, whereas no change was observed in the same patients when on a low sodium diet. Aprotinin reduced the urinary excretion of active kallikrein by 81% and the active to total kallikrein ratio from 24 to 6%. Infusion of aprotinin induced a significant decline in active renin but did not modify inactive renin levels in patients on unrestricted sodium diet as well as in patients on low or high sodium intake. Our data suggest that the inhibition of kallikrein and/or other serine proteases by aprotinin can interfere with renal release of active renin and also support the hypothesis that the renal kallikrein system exerts a regulatory control on sodium excretion in salt replete hypertensives.

INNAPPROPRIATE RENIN SECRETION UNMASKED BY CAPTOPRIL (SQ 14 225) IN HYPERTENSION OF CHRONIC RENAL FAILURE

Captopril (SQ 14 225), an orally active inhibitor of angiotensin-converting enzyme, was given to 7 hypertensive patients with chronic renal failure whose plasma-creatinine ranged from 1·5-7·4 mg/dl; whose plasma-renin activity was normal; whose hypertension was not controlled by previous therapy consisting in 5 patients of three or more antihypertensive drugs; and whose blood-pressures averaged 176/111±11/3 mm Hg. Inhibition of converting enzyme by oral captopril, 200 mg twice daily, reduced blood-pressure to 156/100±9/5 mm Hg. 5 patients needed additional treatment by frusemide 40-250 mg/ day orally. With this combined regimen the blood-pressure of all patients averaged 126/85±4/3 mm Hg after 8±2 weeks of captopril. The drug was well tolerated. These results suggest that inhibition of angiotensin-converting enzyme with or without sodium depletion is an efficient treatment for hypertension associated with chronic renal failure. It appears that although renin levels in patients with this condition may be "normal", they are inappropriate in relation to the subtle degree of sodium retention that occurs with this disorder.

Renin Subgroups in Essential Hypertension: an Analysis and Critique

It has been claimed that measurement of renin levels in patients with essential hypertension enables identifiable subgroups of patients to be demarcated and that these subgroups exhibit important differences in prognosis and response to therapy. Accordingly, plasma renin activity (PRA) was measured in 181 patients referred to hospital outpatients for treatment of hypertension. Fifteen of these were excluded from study because of abnormality of renal function, an abnormal pyelogram or incidental disease. PRA of the remainder showed a smooth unimodal distribution with a 'tail' of high values (17%) which lay above the range of values observed in normotensive subjects. Following seven days treatment with bendrofluazide the percentage rise in PRA was much less than that of age-matched controls. A group of 55 patients (33%) fell below the range encountered in normotensive matched subjects treated similarly, although the distribution of PRA was still smooth and unimodal. Patients were divided into 'high', 'normal' and 'low' renin subgroups. Whilst there were significant differences in age between the high, normal and low renin groups, there were no significant differences in basal blood pressure, response to diuretics or beta blockers. It is concluded that renin levels in hypertension are influenced by several factors and that any attempt to subdivide patients into renin subgroups is therefore arbitrary. Measurement of renin does not significantly assist predicting the blood pressure response to either diuretics or beta-blockers combined with diuretics.