scholarly journals Why Children Are Less Affected by COVID-19 Than Adults: Potential Immunological Factors and the Renin-Angiotensin System Associated Mechanisms

2020 ◽  
Author(s):  
Olga Krogh-Jensen ◽  
Irina Nikitina ◽  
Andrew Donnikov ◽  
Anna Lenyushkina ◽  
Nataliya Degtyareva ◽  
...  
Keyword(s):  
Immune Response ◽  
Transmembrane Protein ◽  
Age Groups ◽  
Renin Angiotensin System ◽  
Scientific Data ◽  
Th2 Response ◽  
Angiotensin System ◽  
Inflammatory Reactions ◽  
Renin Angiotensin ◽  
Anti Inflammatory

The spread of the infection caused by the new coronavirus SARS-CoV-2 (COVID-19) became pandemic on March 11, 2020. From the time of the first cases (in November 2019, Wuhan, China), to date, a large number of COVID-19 observations have been accumulated in different age groups of patients both in China and abroad. Published scientific data allows us to conclude that children suffer from COVID-19 much less often than adults and tolerate the disease in a milder form, often appear to be asymptomatic. There is currently no final answer why children are less susceptible to this virus; however, scientists are increasingly inclined to consider a complex effect of the immune response and components of the renin-angiotensin system (RAS), which according to recent studies affects not only the cardiovascular system, but is also responsible for the activation of inflammatory reactions. A hypothesis of genetic predisposition to the development of severe forms of COVID-19 has recently been made. We conducted a search for publications in the databases and showed current scientific ideas about COVID-19 pathogenesis and factors influencing the disease development in childhood. Childhood immunity may have several protective features against SARS-CoV-2: immaturity of particular elements of the innate immune response, constitutional lymphocytosis with a shift towards anti-inflammatory Th2-response, as well as "trained" immunity. The influence of renin-angiotensin system reactions in this review is shown from two perspectives: expression of ACE2 receptors and polymorphisms of certain genes of this system. It was established that ACE2 transmembrane protein is not only the entry point for the virus but also plays a regulatory role, turning the pro-inflammatory vasoconstrictor angiotensin II into anti-inflammatory angiotensin (1-7), which has vasodilating properties. Higher ACE2 content in children compared with adults helps maintain balance in the renin-angiotensin system and prevents the development of complications. It was also shown that the presence of certain genetic polymorphisms (AGTR1, AGTR2, ACE2, ACE) could determine the imbalance inside the RAS, leading to more pronounced reactions of alveolocytes, vascular endothelium and smooth muscle fibers in response to SARS-CoV-2 infection due to a shift towards vasoconstrictor, proliferative and profibrotic mechanisms.

Responses to converting-enzyme inhibition and hemorrhage in newborn lambs and adult sheep

1987 ◽  
Vol 252 (2) ◽  
pp. R306-R313
Author(s):  
J. C. Rose ◽  
S. M. Block ◽  
K. Flowe ◽  
M. Morris ◽  
S. South ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Enzyme Inhibition ◽  
Age Groups ◽  
Renin Angiotensin System ◽  
Angiotensin Converting Enzyme Inhibition ◽  
Converting Enzyme ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Adult Sheep ◽  
Converting Enzyme Inhibition

We compared the cardiovascular and hormonal responses to angiotensin converting enzyme inhibition and hemorrhage of 20% of blood volume in chronically instrumented unanesthetized newborn lambs and adult sheep. Administration of the nonsulfhydryl-containing converting-enzyme inhibitor enalapril reduced mean arterial pressure in the newborn but not in the adult animals. Blood pressure fell in both age groups after hemorrhage, and the hemorrhage-induced fall in blood pressure, integrated over the period of hypovolemia, was more pronounced when converting-enzyme inhibition was present in the lambs. This was not observed in the adults. Cardiac output fell following hemorrhage in both age groups, and the fall was greater when enalapril was present in the lambs, but this was not the case in the adults. Hemorrhage increased plasma renin activity in both groups, and enalapril augmented this increase. Plasma concentrations of vasopressin and catecholamines increased following hemorrhage within and between groups. Taken together these data suggest that the renin-angiotensin system plays a more important role in the maintenance of cardiovascular homeostasis in newborn lambs than it does in adult sheep, and catecholamine and vasopressin responses to volume loss can occur in the presence of blockade of the renin-angiotensin system.

scholarly journals Cessation of Renin-Angiotensin System Antagonists During the SARS-CoV-2 Pandemic – Do We Have the Evidence?

2020 ◽  
Vol 5 (3) ◽  
pp. 105-109
Author(s):  
Emanuel Blîndu ◽  
Renata Gerculy ◽  
Diana Opincariu ◽  
Daniel Cernica ◽  
Imre Benedek
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Angiotensin Receptor Blockers ◽  
Healthcare Providers ◽  
Age Groups ◽  
Renin Angiotensin System ◽  
Host Cells ◽  
Converting Enzyme ◽  
Converting Enzyme Inhibitors ◽  
Angiotensin System ◽  
Renin Angiotensin

AbstractThe aim of this review is to provide a short update on whether treatment with angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) has beneficial or harmful effects in patients infected with SARS-CoV-2. Epidemiological studies have shown that SARS-CoV-2 infects all age groups, presenting a higher incidence in elderly patients with various comorbidities such as hypertension, diabetes mellitus, and cardiovascular diseases. A large proportion of these patients are treated with ACEIs and ARBs. Since it has been demonstrated that SARS-CoV-2 uses angiotensin converting enzyme type 2 (ACE2) as an entry point into host cells, it is important to know whether ACEIs and ARBs could modify the expression of this enzyme, and thus promote the viral infection. Animal studies and a few studies in humans have shown that renin angiotensin system (RAS) inhibitors increase tissue expression of ACE2, but with potentially beneficial effects. In this context, it is imperative to provide appropriate guidance for clinicians and patients. The major cardiology associations across the world have released statements in which they recommend healthcare providers and patients to continue their treatments for hyper-tension and heart failure as prescribed.

scholarly journals Angiotensin-(1-7) Central Mechanisms After ICV Infusion in Hypertensive Transgenic (mRen2)27 Rats

2021 ◽  
Vol 15 ◽  
Author(s):  
Lucas M. Kangussu ◽  
Marcella Nunes Melo-Braga ◽  
Bruna Soares de Souza Lima ◽  
Robson A. S. Santos ◽  
Hélida Monteiro de Andrade ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Renin Angiotensin System ◽  
Angiotensin System ◽  
Peroxiredoxin 1 ◽  
Renin Angiotensin ◽  
Ace Activity ◽  
Carboxyl Terminal ◽  
Anti Inflammatory ◽  
Inflammatory Profile

Graphical AbstractHypothalamic mechanisms induced by ICV infusion of angiotensin-(1-7) in the transgenic (mRen2)27 hypertensive animals. Ang-(1-7) treatment modulated components of the renin-angiotensin system (RAS), attenuating increased levels of AT1 and ACE activity, and negatively modulated inflammatory profile, by increasing anti-inflammatory IL-10 and decreasing TNFα and iNOS in the hypothalamus. Further, altered oxidative stress/inflammation by ROS mediator, decreasing Uchl1 (ubiquitin carboxyl-terminal hydrolase isozyme L1) while increasing antioxidant peroxiredoxin 1 (figure was created with pictures from biorender.com).

Anti-inflammatory properties of drugs acting on the renin-angiotensin system

2005 ◽  
Vol 41 (9) ◽  
pp. 609 ◽  
Author(s):  
L. Sironi ◽  
E. Nobili ◽  
A. Gianella ◽  
P. Gelosa ◽  
E. Tremoli
Keyword(s):  
Renin Angiotensin System ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Anti Inflammatory
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