How does acei work
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Mechanisms of Action of ACE Inhibitors (ACEi)
Introduction to ACE and ACE Inhibitors
Angiotensin-converting enzyme (ACE) plays a crucial role in the renin-angiotensin system (RAS), which regulates blood pressure and fluid balance. ACE converts angiotensin I (Ang I) into angiotensin II (Ang II), a potent vasoconstrictor that increases blood pressure. ACE inhibitors (ACEi) are medications that inhibit this conversion, thereby reducing blood pressure and alleviating conditions such as hypertension and heart failure Wu2017Tan2018.
Classic Mechanism: Inhibition of Angiotensin II Formation
The primary mechanism by which ACE inhibitors work is by blocking the conversion of Ang I to Ang II. This reduction in Ang II levels leads to vasodilation, decreased blood volume, and ultimately lower blood pressure. This classic pathway is well-documented and forms the basis for the use of ACE inhibitors in managing hypertension and related cardiovascular conditions Wu2017Sitanggang2021.
Emerging Mechanisms: Beyond Angiotensin II Inhibition
Upregulation of ACE2
Recent studies have highlighted additional mechanisms through which ACE inhibitors exert their antihypertensive effects. One such mechanism involves the upregulation of ACE2, an enzyme that counterbalances the effects of ACE by converting Ang II into Ang (1-7), a peptide with vasodilatory and anti-inflammatory properties. This upregulation helps mitigate the harmful effects of elevated Ang II levels .
Improvement of Endothelial Function
ACE inhibitors also contribute to the improvement of endothelial function. Endothelial dysfunction is a key factor in the development of hypertension and other cardiovascular diseases. By enhancing endothelial function, ACE inhibitors help maintain vascular health and reduce blood pressure .
Reduction of Vascular Oxidative Stress and Inflammation
Another significant mechanism is the reduction of vascular oxidative stress and inflammation. ACE inhibitors have been shown to decrease oxidative stress and inflammatory responses in the vascular system, which are critical factors in the pathophysiology of hypertension and other cardiovascular disorders .
Molecular Mechanisms: Interaction with TGF-β1 Pathways
In addition to their effects on blood pressure, ACE inhibitors have been found to influence fibrotic processes in various organs, including the heart, lungs, liver, and kidneys. This is primarily achieved through the down-regulation of Smad and TGF-β1-activated kinase 1 (TAK1) pathways, which are involved in tissue fibrosis and scarring. By inhibiting these pathways, ACE inhibitors promote physiological tissue repair and reduce fibrosis .
Bioactive Peptides and ACE Inhibition
Bioactive peptides derived from food proteins have been identified as natural ACE inhibitors. These peptides exhibit ACE inhibitory activity and have potential therapeutic applications in managing hypertension. The effectiveness of these peptides depends on their molecular size, amino acid composition, and specific interactions with ACE. For instance, peptides with hydrophobic amino acids and specific terminal residues have shown higher ACE inhibitory activity Sitanggang2021Yan2020.
Conclusion
ACE inhibitors are a cornerstone in the treatment of hypertension and cardiovascular diseases. While their primary mechanism involves the inhibition of Ang II formation, emerging research has uncovered additional pathways, including the upregulation of ACE2, improvement of endothelial function, and reduction of oxidative stress and inflammation. Furthermore, natural ACE inhibitory peptides from food sources offer promising therapeutic potential. Understanding these diverse mechanisms enhances our ability to effectively utilize ACE inhibitors in clinical practice.
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