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The interacting physiology of COVID-19 and the renin-angiotensin-aldosterone system: Key agents for treatment.
Lumbers, ER, Head, R, Smith, GR, Delforce, SJ, Jarrott, B, H Martin, J, Pringle, KG
Pharmacology research & perspectives. 2022;(1):e00917
Abstract
SARS-CoV-2 interacting with its receptor, angiotensin-converting enzyme 2 (ACE2), turns the host response to viral infection into a dysregulated uncontrolled inflammatory response. This is because ACE2 limits the production of the peptide angiotensin II (Ang II) and SARS-CoV-2, through the destruction of ACE2, allows the uncontrolled production of Ang II. Recovery from trauma requires activation of both a tissue response to injury and activation of a whole-body response to maintain tissue perfusion. Tissue and circulating renin-angiotensin systems (RASs) play an essential role in the host response to infection and injury because of the actions of Ang II, mediated via its AT1 receptor. Both tissue and circulating arms of the renin angiotensin aldosterone system's (RAAS) response to injury need to be regulated. The effects of Ang II and the steroid hormone, aldosterone, on fluid and electrolyte homeostasis and on the circulation are controlled by elaborate feedback networks that respond to alterations in the composition and volume of fluids within the circulatory system. The role of Ang II in the tissue response to injury is however, controlled mainly by its metabolism and conversion to Ang-(1-7) by the enzyme ACE2. Ang-(1-7) has effects that are contrary to Ang II-AT1 R mediated effects. Thus, destruction of ACE2 by SARS-CoV-2 results in loss of control of the pro-inflammatory actions of Ang II and tissue destruction. Therefore, it is the response of the host to SARS-CoV-2 that is responsible for the pathogenesis of COVID-19.
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Management of hypertension and renin-angiotensin-aldosterone system blockade in adults with diabetic kidney disease: Association of British Clinical Diabetologists and the Renal Association UK guideline update 2021.
Banerjee, D, Winocour, P, Chowdhury, TA, De, P, Wahba, M, Montero, R, Fogarty, D, Frankel, AH, Karalliedde, J, Mark, PB, et al
BMC nephrology. 2022;(1):9
Abstract
People with type 1 and type 2 diabetes are at risk of developing progressive chronic kidney disease (CKD) and end-stage kidney failure. Hypertension is a major, reversible risk factor in people with diabetes for development of albuminuria, impaired kidney function, end-stage kidney disease and cardiovascular disease. Blood pressure control has been shown to be beneficial in people with diabetes in slowing progression of kidney disease and reducing cardiovascular events. However, randomised controlled trial evidence differs in type 1 and type 2 diabetes and different stages of CKD in terms of target blood pressure. Activation of the renin-angiotensin-aldosterone system (RAAS) is an important mechanism for the development and progression of CKD and cardiovascular disease. Randomised trials demonstrate that RAAS blockade is effective in preventing/ slowing progression of CKD and reducing cardiovascular events in people with type 1 and type 2 diabetes, albeit differently according to the stage of CKD. Emerging therapy with sodium glucose cotransporter-2 (SGLT-2) inhibitors, non-steroidal selective mineralocorticoid antagonists and endothelin-A receptor antagonists have been shown in randomised trials to lower blood pressure and further reduce the risk of progression of CKD and cardiovascular disease in people with type 2 diabetes. This guideline reviews the current evidence and makes recommendations about blood pressure control and the use of RAAS-blocking agents in different stages of CKD in people with both type 1 and type 2 diabetes.
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Evaluating the effects of sodium glucose co-transporter -2 inhibitors from a renin-angiotensin-aldosterone system perspective in patients infected with COVID-19: contextualizing findings from the dapagliflozin in respiratory failure in patients with COVID-19 study.
Moustafa, DA, Imran, Z, Ismail, R, Rayan, M, Gadeau, AP, Eldassouki, H, Abdulrahman, N, Mraiche, F
Molecular biology reports. 2022;(3):2321-2324
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Abstract
Numerous studies demonstrate parallels between CVD, type 2 diabetes mellitus (T2DM) and COVID-19 pathology, which accentuate pre-existing complications in patients infected with COVID-19 and potentially exacerbate the infection course. Antidiabetic drugs such as sodium-glucose transporter-2 (SGLT-2) inhibitors have garnered substantial attention recently due to their efficacy in reducing the severity of cardiorenal disease. The effect of SGLT-2 inhibitors in patients with COVID-19 remains unclear particularly since SGLT-2 inhibitors contribute to altering the RAAS cascade activity, which includes ACE-2, the major cell entry receptor for SARS-CoV2. A study, DARE-19, was carried out to unveil the effects of SGLT-2 inhibitor treatment on comorbid disease complications and concomitant COVID-19 outcomes and demonstrated no statistical significance. However, the need for further studies is essential to provide conclusive clinical findings.
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Effects of SGLT2 Inhibitors and GLP-1 Receptor Agonists on Renin-Angiotensin-Aldosterone System.
Puglisi, S, Rossini, A, Poli, R, Dughera, F, Pia, A, Terzolo, M, Reimondo, G
Frontiers in endocrinology. 2021;:738848
Abstract
Sodium-glucose cotransporters inhibitors (SGLT2-i) and GLP-1 receptor agonists (GLP1-RA) are glucose-lowering drugs that are proved to reduce the cardiovascular (CV) risk in type 2 diabetes mellitus (T2DM). In this process, the renin-angiotensin-aldosterone system (RAAS) is assumed to play a role. The inhibition of SGLT2 improves hyperglycemia hampering urinary reabsorption of glucose and inducing glycosuria. This "hybrid" diuretic effect, which couples natriuresis with osmotic diuresis, potentially leads to systemic RAAS activation. However, the association between SGLT2-i and systemic RAAS activation is not straightforward. Available data indicate that SGLT2-i cause plasma renin activity (PRA) increase in the early phase of treatment, while PRA and aldosterone levels remain unchanged in chronic treated patients. Furthermore, emerging studies provide evidence that SGLT2-i might have an interfering effect on aldosterone/renin ratio (ARR) in patients with T2DM, due to their diuretic and sympathoinhibition effects. The cardio- and reno-protective effects of GLP-1-RA are at least in part related to the interaction with RAAS. In particular, GLP1-RA counteract the action of angiotensin II (ANG II) inhibiting its synthesis, increasing the inactivation of its circulating form and contrasting its action on target tissue like glomerular endothelial cells and cardiomyocytes. Furthermore, GLP1-RA stimulate natriuresis inhibiting Na+/H+ exchanger NHE-3, which is conversely activated by ANG II. Moreover, GLP1 infusion acutely reduces circulating aldosterone, but this effect does not seem to be chronically maintained in patients treated with GLP1-RA. In conclusion, both SGLT2-i and GLP1-RA seem to have several effects on RAAS, though additional studies are needed to clarify this relationship.
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Transforming the Care of Patients with Diabetic Kidney Disease.
Brosius, FC, Cherney, D, Gee, PO, Harris, RC, Kliger, AS, Tuttle, KR, Quaggin, SE, ,
Clinical journal of the American Society of Nephrology : CJASN. 2021;(10):1590-1600
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Abstract
Diabetes and its associated complications pose an immediate threat to humankind. Diabetic kidney disease is one of the most devastating complications, increasing the risk of death more than ten-fold over the general population. Until very recently, the only drugs proven and recommended to slow the progression of diabetic kidney disease were angiotensin-converting enzyme inhibitors and angiotensin II type 1 receptor blockers, which act by inhibiting the renin-angiotensin system. Despite their efficacy as kidney and cardiovascular protective therapies and as antihypertensive agents, renin-angiotensin system inhibitors have been grossly underutilized. Moreover, even when renin-angiotensin system inhibitors are used, patients still have a high residual risk of diabetic kidney disease progression. Finally, the kidney-protective effect of renin-angiotensin system inhibitors has been categorically demonstrated only in patients with macroalbuminuria included in the Irbesartan Diabetic Nephropathy Trial (IDNT) and Reduction of Endpoints in NIDDM with the Angiotensin II Antagonist Losartan (RENAAL) trials, not in other individuals. The lack of new therapies to treat diabetic kidney disease over the past 2 decades has therefore represented a tremendous challenge for patients and health care providers alike. In recent years, a number of powerful new therapies have emerged that promise to transform care of patients with diabetes and kidney disease. The challenge to the community is to ensure rapid implementation of these treatments. This white paper highlights advances in treatment, opportunities for patients, challenges, and possible solutions to advance kidney health, and introduces the launch of the Diabetic Kidney Disease Collaborative at the American Society of Nephrology, to aid in accomplishing these goals.
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The LIFT trial: study protocol for a double-blind, randomised, placebo-controlled trial of K+-binder Lokelma for maximisation of RAAS inhibition in CKD patients with heart failure.
Murphy, D, Ster, IC, Kaski, JC, Anderson, L, Banerjee, D
BMC nephrology. 2021;(1):254
Abstract
BACKGROUND CKD is common in heart failure (HF) and associated with morbidity and mortality, yet life-prolonging medications such as renin-angiotensin-aldosterone inhibitors (RAASi) are underused due to risk of hyperkalaemia. Sodium zirconium cyclosilicate (SZC) is a potassium-binding medication that has been shown to reduce incidence of hyperkalaemia in CKD, non-CKD, and HF populations, which we propose will support maximisation of RAASi therapy. METHODS We propose a 1:1 randomised, double-blind, placebo-controlled trial in which participants will receive either SZC or placebo. We will up-titrate participants' RAASi therapy while monitoring their serum potassium levels and adjusting their SZC dose if necessary. Participants with CKD and HF will be recruited from CKD and HF clinics at St George's Hospital. The total study period will be 18 months; 130 participants will be enrolled for approximately two months each following screening. Our primary outcome will be the proportion of participants who achieve maximum RAASi dose while maintaining normokalaemia. Secondary outcomes include participants reaching maximum RAASi dose without severe hyperkalaemia; time from randomisation to hyperkalaemia; time from randomisation to severe hyperkalaemia; number of RAASi dose escalations per participant; final doses of RAASi therapy; changes in quality of life score, eGFR, ACR, serum sodium, troponin T; number and duration of hospital admissions; and within-participant change in serum potassium compared to baseline. DISCUSSION This trial will be the first to examine the use of SZC for the maximisation of RAASi dosing in patients with advanced CKD and HF. We will assess the impact of achieving target RAASi dosing on hospital admission rates and duration of stay, with the hope that optimum RAASi treatment will translate into reduced morbidity and improved QoL. If clinical benefit is demonstrated, we hope that the joint multidisciplinary CKD-HF approach will be expanded. TRIAL REGISTRATION EudraCT number 2020-002946-18. Registered on 08 June 2020. Online record pending.
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Evaluating sources of bias in observational studies of angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker use during COVID-19: beyond confounding.
Cohen, JB, D'Agostino McGowan, L, Jensen, ET, Rigdon, J, South, AM
Journal of hypertension. 2021;(4):795-805
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Abstract
Concerns over ACE inhibitor or ARB use to treat hypertension during COVID-19 remain unresolved. Although studies using more robust methodologies provided some clarity, sources of bias persist and it remains critical to quickly address this question. In this review, we discuss pernicious sources of bias using a causal model framework, including time-varying confounder, collider, information, and time-dependent bias, in the context of recently published studies. We discuss causal inference methodologies that can address these issues, including causal diagrams, time-to-event analyses, sensitivity analyses, and marginal structural modeling. We discuss effect modification and we propose a role for causal mediation analysis to estimate indirect effects via mediating factors, especially components of the renin--angiotensin system. Thorough knowledge of these sources of bias and the appropriate methodologies to address them is crucial when evaluating observational studies to inform patient management decisions regarding whether ACE inhibitors or ARBs are associated with greater risk from COVID-19.
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Upregulation of the Renin-Angiotensin System Pathways and SARS-CoV-2 Infection: The Rationale for the Administration of Zinc-Chelating Agents in COVID-19 Patients.
Zamai, L
Cells. 2021;(3)
Abstract
The article describes the rationale for the administration of zinc-chelating agents in COVID-19 patients. In a previous work I have highlighted that the binding of the SARS-CoV spike proteins to the zinc-metalloprotease ACE2 has been shown to induce ACE2 shedding by activating the zinc-metalloprotease ADAM17, which ultimately leads to systemic upregulation of ACE2 activity. Moreover, based on experimental models, it was also shown the detrimental effect of the excessive systemic activity of ACE2 through its downstream pathways, which leads to "clinical" manifestations resembling COVID-19. In this regard, strong upregulation of circulating ACE2 activity was recently reported in COVID-19 patients, thus supporting the previous hypothesis that COVID-19 may derive from upregulation of ACE2 activity. Based on this, a reasonable hypothesis of using inhibitors that curb the upregulation of both ACE2 and ADAM17 zinc-metalloprotease activities and consequent positive feedback-loops (initially triggered by SARS-CoV-2 and subsequently sustained independently on viral trigger) is proposed as therapy for COVID-19. In particular, zinc-chelating agents such as citrate and ethylenediaminetetraacetic acid (EDTA) alone or in combination are expected to act in protecting from COVID-19 at different levels thanks to their both anticoagulant properties and inhibitory activity on zinc-metalloproteases. Several arguments are presented in support of this hypothesis and based on the current knowledge of both beneficial/harmful effects and cost/effectiveness, the use of chelating agents in the prevention and therapy of COVID-19 is proposed. In this regard, clinical trials (currently absent) employing citrate/EDTA in COVID-19 are urgently needed in order to shed more light on the efficacy of zinc chelators against SARS-CoV-2 infection in vivo.
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Fibrinogen and a Triad of Thrombosis, Inflammation, and the Renin-Angiotensin System in Premature Coronary Artery Disease in Women: A New Insight into Sex-Related Differences in the Pathogenesis of the Disease.
Kryczka, KE, Kruk, M, Demkow, M, Lubiszewska, B
Biomolecules. 2021;(7)
Abstract
Coronary artery disease (CAD) is the leading cause of morbidity and mortality in women worldwide. Its social impact in the case of premature CAD is particularly devastating. Many differences in the presentation of the disease in women as compared to men, including atypical symptoms, microvascular involvement, and differences in pathology of plaque formation or progression, make CAD diagnosis in women a challenge. The contribution of different risk factors, such as smoking, diabetes, hyperlipidemia, or obesity, may vary between women and men. Certain pathological pathways may have different sex-related magnitudes on CAD formation and progression. In spite of the already known differences, we lack sufficiently powered studies, both clinical and experimental, that assess the multipathogenic differences in CAD formation and progression related to sex in different age periods. A growing quantity of data that are presented in this article suggest that thrombosis with fibrinogen is of more concern in the case of premature CAD in women than are other coagulation factors, such as factors VII and VIII, tissue-type plasminogen activator, and plasminogen inhibitor-1. The rise in fibrinogen levels in inflammation is mainly affected by interleukin-6 (IL-6). The renin-angiotensin (RA) system affects the inflammatory process by increasing the IL-6 level. Unlike in men, in young women, the hypertensive arm of the RA system is naturally downregulated by estrogens. At the same time, estrogens promote the fibrinolytic path of the RA system. In young women, the promoted fibrinolytic process upregulates IL-6 release from leukocytes via fibrin degradation products. Moreover, fibrinogen, whose higher levels are observed in women, increases IL-6 synthesis and exacerbates inflammation, contributing to CAD. Therefore, the synergistic interplay between thrombosis, inflammation, and the RA system appears to have a more significant influence on the underlying CAD atherosclerotic plaque formation in young women than in men. This issue is further discussed in this review. Fibrinogen is the biomolecule that is central to these three pathways. In this review, fibrinogen is shown as the biomolecule that possesses a different impact on CAD formation, progression, and destabilization in women to that observed in men, being more pathogenic in women at the early stages of the disease than in men. Fibrinogen is a three-chain glycoprotein involved in thrombosis. Although the role of thrombosis is of great magnitude in acute coronary events, fibrinogen also induces atherosclerosis formation by accumulating in the arterial wall and enabling low-density lipoprotein cholesterol aggregation. Its level rises during inflammation and is associated with most cardiovascular risk factors, particularly smoking and diabetes. It was noted that fibrinogen levels were higher in women than in men as well as in the case of premature CAD in women. The causes of this phenomenon are not well understood. The higher fibrinogen levels were found to be associated with a greater extent of coronary atherosclerosis in women with CAD but not in men. Moreover, the lysability of a fibrin clot, which is dependent on fibrinogen properties, was reduced in women with subclinical CAD compared to men at the same stage of the disease, as well as in comparison to women without coronary artery atherosclerosis. These findings suggest that the magnitude of the pathological pathways contributing to premature CAD differs in women and men, and they are discussed in this review. While many gaps in both experimental and clinical studies on sex-related differences in premature CAD exist, further studies on pathological pathways are needed.
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Renin-angiotensin-aldosterone system inhibitors and SARS-CoV-2 infection: an analysis from the veteran's affairs healthcare system.
Sandhu, AT, Kohsaka, S, Lin, S, Woo, CY, Goldstein, MK, Heidenreich, PA
American heart journal. 2021;:46-57
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Abstract
BACKGROUND Angiotensin-converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB) are known to impact the functional receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The association between chronic therapy with these medications and infection risk remains unclear. OBJECTIVES The objective was to determine the association between prior ACEI or ARB therapy and SARS-CoV-2 infection among patients with hypertension in the U.S. Veteran's Affairs health system. METHODS We compared the odds of SARS-CoV-2 infection among three groups: patients treated with ACEI, treated with ARB, or treated with alternate first-line anti-hypertensives without ACEI/ARB. We excluded patients with alternate indications for ACEI or ARB therapy. We performed an augmented inverse propensity weighted analysis with adjustment for demographics, region, comorbidities, vitals, and laboratory values. RESULTS Among 1,724,723 patients with treated hypertension, 659,180 were treated with ACEI, 310,651 with ARB, and 754,892 with neither. Before weighting, patients treated with ACEI or ARB were more likely to be diabetic and use more anti-hypertensives. There were 13,278 SARS-CoV-2 infections (0.8%) between February 12, 2020 and August 19, 2020. Patients treated with ACEI had lower odds of SARS-CoV-2 infection (odds ratio [OR] 0.93; 95% CI: 0.89-0.97) while those treated with ARB had similar odds (OR 1.02; 95% CI: 0.96-1.07) compared with patients treated with alternate first-line anti-hypertensives without ACEI/ARB. In falsification analyses, patients on ACEI did not have a difference in their odds of unrelated outcomes. CONCLUSIONS Our results suggest the safety of continuing ACEI and ARB therapy. The association between ACEI therapy and lower odds of SARS-CoV-2 infection requires further investigation.