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Genetic associations between genes in the renin-angiotensin-aldosterone system and renal disease: a systematic review and meta-analysis.
Smyth, LJ, Cañadas-Garre, M, Cappa, RC, Maxwell, AP, McKnight, AJ
BMJ open. 2019;(4):e026777
Abstract
BACKGROUND Chronic kidney disease (CKD) is defined by abnormalities in kidney structure and/or function present for more than 3 months. Worldwide, both the incidence and prevalence rates of CKD are increasing. The renin-angiotensin-aldosterone system (RAAS) regulates fluid and electrolyte balance through the kidney. RAAS activation is associated with hypertension, which is directly implicated in causation and progression of CKD. RAAS blockade, using drugs targeting individual RAAS mediators and receptors, has proven to be renoprotective. OBJECTIVES To assess genomic variants present within RAAS genes, ACE, ACE2, AGT, AGTR1, AGTR2 and REN, for association with CKD. DESIGN AND DATA SOURCES A systematic review and meta-analysis of observational research was performed to evaluate the RAAS gene polymorphisms in CKD using both PubMed and Web of Science databases with publication date between the inception of each database and 31 December 2018. Eligible articles included case-control studies of a defined kidney disease and included genotype counts. ELIGIBILITY CRITERIA Any paper was removed from the analysis if it was not written in English or Spanish, was a non-human study, was a paediatric study, was not a case-control study, did not have a renal disease phenotype, did not include data for the genes, was a gene expression-based study or had a pharmaceutical drug focus. RESULTS A total of 3531 studies were identified, 114 of which met the inclusion criteria. Genetic variants reported in at least three independent publications for populations with the same ethnicity were determined and quantitative analyses performed. Three variants returned significant results in populations with different ethnicities at p<0.05: ACE insertion, AGT rs699-T allele and AGTR1 rs5186-A allele; each variant was associated with a reduced risk of CKD development. CONCLUSIONS Further biological pathway and functional analyses of the RAAS gene polymorphisms will help define how variation in components of the RAAS pathway contributes to CKD.
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Implications of renin-angiotensin-system blocker discontinuation in acute decompensated heart failure with systolic dysfunction.
Darden, D, Drazner, MH, Mullens, W, Dupont, M, Tang, WHW, Grodin, JL
Clinical cardiology. 2019;(10):1010-1018
Abstract
BACKGROUND Renin-angiotensin-system blockers (RASB) improve clinical outcomes in patients with chronic heart failure with reduced fraction; however, there remains ambiguity whether RASB therapy should be continued during the treatment of acute decompensated heart failure (ADHF). HYPOTHESIS In comparison to patients with RASB use, RASB discontinuation in ADHF will be associated with worsening renal function, hypotension, and adverse long-term clinical outcomes. METHODS Patients in the Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization (ESCAPE) trial were separated into four groups based on RASB use at baseline and discharge: continuation (n = 316), discontinuation (n = 21), initiation (n = 42), and nonuse (n = 23). Post-discharge outcomes were validated in an independent ADHF cohort admitted to the Cleveland Clinic (n = 253). RESULTS RASB discontinuation and nonuse were associated with higher serial creatinine and blood urea nitrogen levels than RASB continuation or initiation (P < .001 for both), but not with serial potassium and systolic blood pressure measurements. No other clinical parameter changes were significant. In comparison to RASB continuation, RASB discontinuation and nonuse was associated with ~75% increased risk of a 180-day composite of death, transplant, or rehospitalization (HR 1.87, 95% CI 1.09-3.20, P = 0.02 and HR 1.72, CI 1.04-2.82, P = .03, respectively). Post-discharge outcomes were similar in the validation cohort. CONCLUSION Compared to RASB continuation, RASB discontinuation and nonuse were associated with higher baseline and serial creatinine levels during treatment for ADHF, but not with changes in SBP and potassium levels. Furthermore, RASB discontinuation and nonuse in ADHF were associated with an increased risk of adverse clinical outcomes.
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Diuretic Effects of Sodium Glucose Cotransporter 2 Inhibitors and Their Influence on the Renin-Angiotensin System.
Ansary, TM, Nakano, D, Nishiyama, A
International journal of molecular sciences. 2019;(3)
Abstract
The renin-angiotensin system (RAS) plays an important role in regulating body fluids and blood pressure. However, inappropriate activation of the RAS contributes to the pathogenesis of cardiovascular and renal diseases. Recently, sodium glucose cotransporter 2 (SGLT2) inhibitors have been used as anti-diabetic agents. SGLT2 inhibitors induce glycosuria and improve hyperglycemia by inhibiting urinary reabsorption of glucose. However, in the early stages of treatment, these inhibitors frequently cause polyuria and natriuresis, which potentially activate the RAS. Nevertheless, the effects of SGLT2 inhibitors on RAS activity are not straightforward. Available data indicate that treatment with SGLT2 inhibitors transiently activates the systemic RAS in type 2 diabetic patients, but not the intrarenal RAS. In this review article, we summarize current evidence of the diuretic effects of SGLT2 inhibitors and their influence on RAS activity.
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Renin Angiotensin Aldosterone System Blockades Does Not Protect Residual Renal Function in Patients with Hemodialysis at 1 Year After Dialysis Initiation: A Prospective Observational Cohort Study.
Yoo, KD, Kim, CT, Kwon, S, Lee, J, Oh, YK, Kang, SW, Yang, CW, Kim, YL, Kim, YS, Lim, CS, et al
Scientific reports. 2019;(1):18103
Abstract
The beneficial effects of renin angiotensin aldosterone system (RAAS) blockade on residual renal function (RRF) in patients who have just initiated hemodialysis (HD) have been inconclusive. In this study, 935 patients with incident HD from a nationwide prospective observational cohort in Korea were included for analysis. The primary outcome showed that RRF as demonstrated by urine volume changes over 0, 3, and 12 months differed between the RAAS blockade and control groups. Mixed-effects linear regression was used to compare RRF between the groups. Patients in the RAAS group had a greater proportion of higher urine volume at study enrollment compared to the control group, but there was no difference in baseline characteristics, heart function, and dialysis-related indices. After adjusting for confounding factors, the RAAS group did not provide a significant benefit to RRF in a mixed-effects linear regression (p = 0.51). Male gender, high Charlson comorbidity index, diuretic use, and high weekly ultrafiltration volume were associated with faster decline in RRF. The RAAS group failed to provide a protective effect for the development of anuria 1 year after initiating dialysis based on the multivariate logistic regression (OR 0.73 95% CI 0.25-2.13, p = 0.57). In Korean patients with incident HD, RAAS blockade did not provide a protective effect for RRF after 1 year. Further research is needed to clarify the optimal treatment for preserving RRF in HD patients.
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Pivotal clinical trials, meta-analyses and current guidelines in the treatment of hyperkalemia.
Bianchi, S, Regolisti, G
Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association. 2019;(Suppl 3):iii51-iii61
Abstract
Hyperkalemia (HK) is the most common electrolyte disturbance observed in patients with advanced stages of chronic kidney disease (CKD), is a potentially life-threatening clinical condition due to an increased risk of fatal arrhythmias, and strongly impacts the quality of life and prognosis of CKD patients. Moreover, while renin-angiotensin-aldosterone system inhibitors (RAASIs) represent the most cardio-nephro-protective drugs used in clinical practice, the treatment with these drugs per se increases serum potassium (sK) values, particularly when heart failure and diabetes mellitus coexist. In fact, the onset or recurrence of HK is frequently associated with not starting, down-titrating or withdrawing RAASIs, and is an indication to begin renal replacement treatment in end-stage renal disease. Current strategies aimed at preventing and treating chronic HK are still unsatisfactory, as evidenced by the relatively high prevalence of HK also in patients under stable nephrology care, and even in the ideal setting of randomized clinical trials. Indeed, dietary potassium restriction, the use of sodium bicarbonate or diuretics, the withdrawal or down-titration of RAASIs, or the administration of old potassium binders, namely sodium polystyrene sulphonate and calcium polystyrene sulphonate, have limited efficacy and are poorly tolerated; therefore, these strategies are not suitable for long-term control of sK. As such, there is an important unmet need for novel therapeutic options for the chronic management of patients at risk for HK. The development of new potassium binders may change the treatment landscape in the near future. This review summarizes the current evidence on the treatment of chronic HK in cardio-renal patients.
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6.
Cardiorenal Syndrome and Heart Failure-Challenges and Opportunities.
Yogasundaram, H, Chappell, MC, Braam, B, Oudit, GY
The Canadian journal of cardiology. 2019;(9):1208-1219
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Abstract
Cardiorenal syndromes (CRS) describe concomitant bidirectional dysfunction of the heart and kidneys in which 1 organ initiates, perpetuates, and/or accelerates decline of the other. CRS are common in heart failure and universally portend worsened prognosis. Despite this heavy disease burden, the appropriate diagnosis and classification of CRS remains problematic. In addition to the hemodynamic drivers of decreased renal perfusion and increased renal vein pressure, induction of the renin-angiotensin-aldosterone system, stimulation of the sympathetic nervous system, disruption of balance between nitric oxide and reactive oxygen species, and inflammation are implicated in the pathogenesis of CRS. Medical therapy of heart failure including renin-angiotensin-aldosterone system inhibition and β-adrenergic blockade can blunt these deleterious processes. Renovascular disease can accelerate the progression of CRS. Volume overload and diuretic resistance are common and complicate the management of CRS. In heart failure and CRS being treated with diuretics, worsening creatinine is not associated with worsened outcome if clinical decongestion is achieved. Adjunctive therapy is often required in the management of volume overload in CRS, but evidence for these therapies is limited. Anemia and iron deficiency are importantly associated with CRS and might amplify decline of cardiac and renal function. End-stage cardiac and/or renal disease represents an especially poor prognosis with limited therapeutic options. Overall, worsening renal function is associated with significantly increased mortality. Despite progress in the area of CRS, there are still multiple pathophysiological and clinical aspects of CRS that need further research to eventually develop effective therapeutic options.
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A pilot double-blind randomized placebo-controlled crossover pharmacodynamic study of the centrally active aminopeptidase A inhibitor, firibastat, in hypertension.
Azizi, M, Courand, PY, Denolle, T, Delsart, P, Zhygalina, V, Amar, L, Lantelme, P, Mounier-Vehier, C, De Mota, N, Balavoine, F, et al
Journal of hypertension. 2019;(8):1722-1728
Abstract
OBJECTIVES We conducted a pilot multicenter double-blind randomized placebo-controlled crossover pharmacodynamic study to evaluate the blood pressure (BP) and the hormonal effects of firibastat, a first-in-class aminopeptidase A inhibitor prodrug, in patients with hypertension. METHODS Thirty-four patients with daytime ambulatory BP of at least 135/85 mmHg and less than 170/105 mmHg, after a 2-week run-in period were randomly assigned to receive either firibastat (250 mg b.i.d. for 1 week uptitrated to 500 mg b.i.d. for 3 weeks) and then placebo for 4 weeks each or vice versa, with a 2-week washout period on placebo. RESULTS At 4 weeks, daytime ambulatory systolic BP (SBP) decreased by 2.7 mmHg (95% confidence interval -6.5 to +1.1 mmHg) with firibastat versus placebo (P = 0.157). Office SBP decreased by 4.7 mmHg (95% confidence interval -11.1 to +1.8 mmHg) with firibastat versus placebo (P = 0.151). However, more the basal daytime ambulatory SBP was elevated, more the firibastat-induced BP decrease was marked. Firibastat did not influence 24h-ambulatory heart rate. Firibastat had no effect on plasma renin, aldosterone, apelin and copeptin concentrations. No major adverse events occurred. There was one episode of reversible skin allergy with facial edema. CONCLUSION In patients with hypertension, a 4-week treatment with firibastat, tended to decrease daytime SBP relative to placebo. Firibastat did not modify the activity of the systemic renin-angiotensin system These results have justified designing a larger, powered trial of longer duration to fully assess its safety and effectiveness. CLINICAL TRIAL REGISTRATION http://www.clinicaltrials.gov. NCT02322450.
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Optimally managing hyperkalemia in patients with cardiorenal syndrome.
Wang, AY
Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association. 2019;(Suppl 3):iii36-iii44
Abstract
Renin-angiotensin-aldosterone system inhibitors (RAASi) are now a standard treatment in most patients with cardiovascular disease, especially in those with heart failure (HF). The European Society of Cardiology and the American College of Cardiology/American Heart Association gave a Class IA recommendation for the use of RAASi in the treatment of Classes II-IV symptomatic HF with reduced ejection fraction (HFREF), based on their strong clinical benefits of lowering all-cause mortality and HF hospitalizations in these subjects. However, RAASi therapy or adding mineralocorticoid receptor antagonists in subjects receiving background angiotensin-converting enzyme inhibitors or angiotensin receptor blockers may be associated with an increased risk of hyperkalemia (HK), especially in those with reduced kidney function. As a result, a significant proportion of these subjects either have RAASi dose reduced or more often discontinued when they develop HK. Discontinuation of RAASi in patients hospitalized with HFREF was associated with higher postdischarge mortality and rehospitalization rates, while optimal dosing of RAASi significantly reduced median hospital stays, outpatient visits and related costs. Thus, effective treatment is required to lower potassium level and maintain normokalemia in subjects with HF and reduced kidney disease who develop or are at risk of HK, thus enabling them to continue their RAASi therapy and maximize benefits from RAASi. In this review, we provide an up-to-date review of the prevalence and significance of HK in patients with cardiorenal syndrome, as well as their optimal management of HK with recent novel therapies.
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Mechanisms linking the renin-angiotensin system, obesity, and breast cancer.
Rasha, F, Ramalingam, L, Gollahon, L, Rahman, RL, Rahman, SM, Menikdiwela, K, Moustaid-Moussa, N
Endocrine-related cancer. 2019;(12):R653-R672
Abstract
Obesity is a complex disease and a global epidemic. It is a risk factor for other chronic diseases including breast cancer, especially in women after menopause. Diverse etiologies underlie the relationship between obesity and breast cancer. Adipose tissue is in part responsible for these interactions. In obesity, adipose tissue undergoes several metabolic dysregulations resulting in the secretion of many pro-inflammatory cytokines, growth factors, and hormones which in turn, can promote tumor microenvironment (TME) formation and cancer progression within the breast tissue. Angiotensin II (Ang II) is a well-known hypertensive hormone produced systemically and locally by the renin-angiotensin system (RAS). Activation of this system in obesity is a potential contributor to local and systemic inflammation in breast adipose tissue. Ang II actions are primarily mediated through binding to its two receptors, type 1 (AT1R) and type 2 (AT2R). RAS inhibitors include angiotensin-converting enzyme inhibitors (ACE-I) and angiotensin receptor blockers (ARBs) which are currently prescribed as safe antihypertensive therapies. Recent studies have explored the potential use of ACE-I and ARBs in breast cancer patients as anti-tumor agents. Therefore, it is vital to understand the role of RAS in breast cancer and identify mechanisms of Ang II and RAS inhibitors in the TME and in obesity and breast cancer crosstalk. In this review, we performed a detailed analysis and discussed mechanisms of Ang II-AT1R interactions in breast cancer with emphasis on obesity-associated breast cancer. We further summarized recent in vitro, in vivo and human studies that used ACE-I/ARB interventions to improve breast cancer outcomes.
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Antifibrotic Roles of RAAS Blockers: Update.
Zhang, YY, Yu, Y, Yu, C
Advances in experimental medicine and biology. 2019;:671-691
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Abstract
The rennin-angiotensin-aldosterone system (RAAS) has been well documented in regulating blood pressure, fluid volume, and sodium balance. Overactivity of RAAS promotes both systemic and regional glomerular capillary hypertension, which could induce hemodynamic injury to the glomerulus, leading to kidney damage and renal fibrosis via profibrotic and proinflammatory pathway. Therefore, the use of RAAS inhibitors (i.e., ACEIs, ARBs, and MRAs) as the optional therapy has been demonstrated to prevent proteinuria, and kidney fibrosis and slow the decline of renal function effectively in the process of kidney disease during the last few decades. Recently, several new components of the RAAS have been discovered, including ACE2 and the corresponding ACE2/Ang (1-7)/Mas axis, which are also present in the kidney. Besides the classic RAAS inhibitors target the angiotensin-AT1-aldosterone axis, with the expanding knowledge about RAAS, a number of potential therapeutic targets in this system is emerging. Newer agents that are more specific are being developed. The present chapter outlines the insights of the RAAS agents (classic RAAS antagonists/the new RAAS drugs), and discusses its clinical application in the combat of renal fibrosis.