Blocking of Type 1 Angiotensin II Receptor Inhibits T-lymphocyte Activation and IL-2 Production

The immunomodulatory effects of antihypertensive therapy: A review

Hypertension remains the leading preventable risk factor for stroke and coronary artery disease, significantly contributing to all-cause global mortality and predisposing patients to renal and heart failure, as well as peripheral vascular disease. Due to the widespread usage of antihypertensive drugs, global mean blood pressure has remained unchanged or even slightly decreased over the past four decades. However, considering the broad spectrum of mechanisms involved in the action of antihypertensive drugs and the prevalence of their target receptors on immune cells, possible immunomodulatory effects which may exert beneficial effects of lowering blood pressure but also potentially alter immune function should be considered. In this review, we attempt to assess the consequences to immune system function of administering the five most commonly prescribed groups of antihypertensive drugs and to explain the mechanisms behind those interactions. Finally, we show potential gaps in our understanding of the effects of antihypertensive drugs on patient health. With regard to the widespread use of these drugs in the adult population worldwide, the discussed results may be of vital importance to evidence-based decision-making in daily clinical practice.

Angiotensin II Type I Receptor (AT1R): The Gate towards COVID-19-Associated Diseases

The binding of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike glycoprotein to its cellular receptor, the angiotensin-converting enzyme 2 (ACE2), causes its downregulation, which subsequently leads to the dysregulation of the renin-angiotensin system (RAS) in favor of the ACE-angiotensin II (Ang II)-angiotensin II type I receptor (AT1R) axis. AT1R has a major role in RAS by being involved in several physiological events including blood pressure control and electrolyte balance. Following SARS-CoV-2 infection, pathogenic episodes generated by the vasoconstriction, proinflammatory, profibrotic, and prooxidative consequences of the Ang II-AT1R axis activation are accompanied by a hyperinflammatory state (cytokine storm) and an acute respiratory distress syndrome (ARDS). AT1R, a member of the G protein-coupled receptor (GPCR) family, modulates Ang II deleterious effects through the activation of multiple downstream signaling pathways, among which are MAP kinases (ERK 1/2, JNK, p38MAPK), receptor tyrosine kinases (PDGF, EGFR, insulin receptor), and nonreceptor tyrosine kinases (Src, JAK/STAT, focal adhesion kinase (FAK)), and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. COVID-19 is well known for generating respiratory symptoms, but because ACE2 is expressed in various body tissues, several extrapulmonary pathologies are also manifested, including neurologic disorders, vasculature and myocardial complications, kidney injury, gastrointestinal symptoms, hepatic injury, hyperglycemia, and dermatologic complications. Therefore, the development of drugs based on RAS blockers, such as angiotensin II receptor blockers (ARBs), that inhibit the damaging axis of the RAS cascade may become one of the most promising approaches for the treatment of COVID-19 in the near future. We herein review the general features of AT1R, with a special focus on the receptor-mediated activation of the different downstream signaling pathways leading to specific cellular responses. In addition, we provide the latest insights into the roles of AT1R in COVID-19 outcomes in different systems of the human body, as well as the role of ARBs as tentative pharmacological agents to treat COVID-19.

Immunomodulatory Activity of the Most Commonly Used Antihypertensive Drugs-Angiotensin Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers

This review article is focused on antihypertensive drugs, namely angiotensin converting enzyme inhibitors (ACEI) and angiotensin II receptor blockers (ARB), and their immunomodulatory properties reported in hypertensive patients as well as in experimental settings involving studies on animal models and cell lines. The immune regulatory action of ACEI and ARB is mainly connected with the inhibition of proinflammatory cytokine secretion, diminished expression of adhesion molecules, and normalization of CRP concentration in the blood plasma. The topic has significant importance in future medical practice in the therapy of patients with comorbidities with underlying chronic inflammatory responses. Thus, this additional effect of immune regulatory action of ACEI and ARB may also benefit the treatment of patients with metabolic syndrome, allergies, or autoimmune disorders.

Induced dysregulation of ACE2 by SARS-CoV-2 plays a key role in COVID-19 severity

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the cause of COVID-19, is reported to increase the rate of mortality worldwide. COVID-19 is associated with acute respiratory symptoms as well as blood coagulation in the vessels (thrombosis), heart attack and stroke. Given the requirement of angiotensin converting enzyme 2 (ACE2) receptor for SARS-CoV-2 entry into host cells, here we discuss how the downregulation of ACE2 in the COVID-19 patients and virus-induced shift in ACE2 catalytic equilibrium, change the concentrations of substrates such as angiotensin II, apelin-13, dynorphin-13, and products such as angiotensin (1–7), angiotensin (1–9), apelin-12, dynorphin-12 in the human body. Substrates accumulation ultimately induces inflammation, angiogenesis, thrombosis, neuronal and tissue damage while diminished products lead to the loss of the anti-inflammatory, anti-thrombotic and anti-angiogenic responses. In this review, we focus on the viral-induced imbalance between ACE2 substrates and products which exacerbates the severity of COVID-19. Considering the roadmap, we propose multiple therapeutic strategies aiming to rebalance the products of ACE2 and to ameliorate the symptoms of the disease.

Role of interleukin-23/interleukin-17 axis in T-cell-mediated actions in hypertension

Current knowledge suggests that hypertension is in part mediated by immune mechanisms. Both interleukin (IL)-23 and IL-17 are up-regulated in several experimental hypertensive rodent models, as well as in hypertensive humans in observational studies. Recent preclinical studies have shown that either IL-23 or IL-17A treatment induce blood pressure elevation. However, the IL-23/IL-17 axis has not been a major therapeutic target in hypertension, unlike in other autoimmune diseases. In this review, we summarize current knowledge on the role of these cytokines in immune mechanisms contributing to hypertension, and discuss the potential of IL-23/IL-17-targeted therapy for treatment of hypertension.

Immunological aging and clinical consequences

Immunosenescence is defined as the changes in the immune system associated with age. It is a progressive and irreversible process involving a decrease in the number of naïve T and B cells, NK cells cytotoxic and activity, and disruption of pro and anti-inflammatory balance by altering the production of IL-2, -4, -6, -10, -10, TNF-α, interferon γ and others. With age there is an increase in autoimmunity and generalized inflammation with simultaneous immunodeficiency, which results in greater susceptibility to infectious diseases, a decrease in reactivity to prophylactic vaccinations, the incidence of autoimmune diseases, and increased risk of infectious injury complications, exacerbation of symptoms of chronic diseases and an insufficient response to the presence of cells cancer. For years, based on the analysis of the frequency of viral and bacterial infections, immunological indicators and inflammation, attempts have been made to develop the immune risk profile (IRP) and effective methods of preventing disorders of the immune system and prolonging the functional capacity of the elderly.