Liver fibrosis: a balance of ACEs?

2007 ◽  
Vol 113 (3) ◽  
pp. 109-118 ◽  
Author(s):  
Fiona J. Warner ◽  
John S. Lubel ◽  
Geoffrey W. McCaughan ◽  
Peter W. Angus
Keyword(s):  
Angiotensin Ii ◽  
Growth Factor ◽  
Liver Fibrosis ◽  
Liver Injury ◽  
Angiotensin Converting Enzyme ◽  
Transforming Growth Factor ◽  
Tissue Growth ◽  
Chronic Liver ◽  
Converting Enzyme ◽  
Chronic Liver Injury

There is an increasing body of evidence to suggest that the RAS (renin–angiotensin system) contributes to tissue injury and fibrosis in chronic liver disease. A number of studies have shown that components of a local hepatic RAS are up-regulated in fibrotic livers of humans and in experimental animal models. Angiotensin II, the main physiological effector molecule of this system, mediates liver fibrosis by stimulating fibroblast proliferation (myofibroblast and hepatic stellate cells), infiltration of inflammatory cells, and the release of inflammatory cytokines and growth factors such as TGF (transforming growth factor)-β1, IL (interleukin)-1β, MCP (monocyte chemoattractant protein)-1 and connective tissue growth factor. Furthermore, blockade of the RAS by ACE (angiotensin-converting enzyme) inhibitors and angiotensin type 1 receptor antagonists significantly attenuate liver fibrosis in experimental models of chronic liver injury. In 2000 ACE2 (angiotensin-converting enzyme 2), a human homologue of ACE, was identified. ACE2 efficiently degrades angiotensin II to angiotensin-(1–7), a peptide which has recently been shown to have both vasodilatory and tissue protective effects. This suggests that ACE2 and its products may be part of an alternate enzymatic pathway in the RAS, which counterbalances the generation and actions of angiotensin II, the ACE2–angiotensin-(1–7)–Mas axis. This review focuses on the potential roles of the RAS, angiotensin II and ACE2 in chronic liver injury and fibrogenesis.

Suppression of transforming growth factor-β results in upregulation of transcription of regeneration factors after chronic liver injury

2004 ◽  
Vol 41 (6) ◽  
pp. 974-982 ◽  
Author(s):  
Toru Nakamura ◽  
Takato Ueno ◽  
Masaharu Sakamoto ◽  
Ryuichiro Sakata ◽  
Takuji Torimura ◽  
...  
Keyword(s):  
Growth Factor ◽  
Liver Injury ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Chronic Liver ◽  
Chronic Liver Injury

Cellular Mechanisms of Tissue Fibrosis. 5. Novel insights into liver fibrosis

2013 ◽  
Vol 305 (8) ◽  
pp. C789-C799 ◽  
Author(s):  
Ariane Mallat ◽  
Sophie Lotersztajn
Keyword(s):  
Liver Fibrosis ◽  
Liver Injury ◽  
Cell Injury ◽  
Parenchymal Cell ◽  
Chronic Liver ◽  
Special Focus ◽  
Chronic Liver Injury ◽  
Cellular Mechanisms ◽  
Extracellular Matrix Components ◽  
Liver Fibrogenesis

Liver fibrosis is the common scarring reaction associated with chronic liver injury that results from prolonged parenchymal cell injury and/or inflammation. The fibrogenic response is characterized by progressive accumulation of extracellular matrix components enriched in fibrillar collagens and a failure of matrix turnover. This process is driven by a heterogeneous population of hepatic myofibroblasts, which mainly derive from hepatic stellate cells and portal fibroblasts. Regression of fibrosis can be achieved by the successful control of chronic liver injury, owing to termination of the fibrogenic reaction following clearance of hepatic myofibroblasts and restoration of fibrolytic pathways. Understanding of the complex network underlying liver fibrogenesis has allowed the identification of a large number of antifibrotic targets, but no antifibrotic drug has as yet been approved. This review will highlight recent advances regarding the mechanisms that regulate liver fibrogenesis and fibrosis regression, with special focus on novel signaling pathways and the role of inflammatory cells. Translation of these findings to therapies will require continued efforts to develop multitarget therapeutic approaches that will improve the grim prognosis of liver cirrhosis.

scholarly journals Loss of Apelin Augments Angiotensin II-Induced Cardiac Dysfunction and Pathological Remodeling

2019 ◽  
Vol 20 (2) ◽  
pp. 239 ◽  
Author(s):  
Teruki Sato ◽  
Ayumi Kadowaki ◽  
Takashi Suzuki ◽  
Hiroshi Ito ◽  
Hiroyuki Watanabe ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Angiotensin Converting Enzyme ◽  
Knockout Mice ◽  
Cardiac Dysfunction ◽  
Transforming Growth Factor ◽  
Heart Function ◽  
Dependent Manner ◽  
Ang Ii ◽  
Converting Enzyme ◽  
Pathological Remodeling

Apelin is an inotropic and cardioprotective peptide that exhibits beneficial effects through activation of the APJ receptor in the pathology of cardiovascular diseases. Apelin induces the expression of angiotensin-converting enzyme 2 (ACE2) in failing hearts, thereby improving heart function in an angiotensin 1–7-dependent manner. Whether apelin antagonizes the over-activation of the renin–angiotensin system in the heart remains elusive. In this study we show that the detrimental effects of angiotensin II (Ang II) were exacerbated in the hearts of aged apelin-gene-deficient mice. Ang II-mediated cardiac dysfunction and hypertrophy were augmented in apelin knockout mice. The loss of apelin increased the ratio of angiotensin-converting enzyme (ACE) to ACE2 expression in the Ang II-stressed hearts, and Ang II-induced cardiac fibrosis was markedly enhanced in apelin knockout mice. mRNA expression of pro-fibrotic genes, such as transforming growth-factor beta (TGF-β) signaling, were significantly upregulated in apelin knockout hearts. Consistently, treatment with the ACE-inhibitor Captopril decreased cardiac contractility in apelin knockout mice. In vitro, apelin ameliorated Ang II-induced TGF-β expression in primary cardiomyocytes, accompanied with reduced hypertrophy. These results provide direct evidence that endogenous apelin plays a crucial role in suppressing Ang II-induced cardiac dysfunction and pathological remodeling.

scholarly journals Liver fibrosis is driven by protease‐activated receptor‐1 expressed by hepatic stellate cells in experimental chronic liver injury

2020 ◽  
Vol 4 (5) ◽  
pp. 906-917
Author(s):  
Lauren G. Poole ◽  
Asmita Pant ◽  
Holly M. Cline‐Fedewa ◽  
Kurt J. Williams ◽  
Bryan L. Copple ◽  
...  
Keyword(s):  
Liver Fibrosis ◽  
Liver Injury ◽  
Hepatic Stellate Cells ◽  
Stellate Cells ◽  
Chronic Liver ◽  
Chronic Liver Injury ◽  
Protease Activated Receptor 1

scholarly journals α2-Adrenergic Receptor in Liver Fibrosis: Implications for the Adrenoblocker Mesedin

Cells ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 456 ◽  
Author(s):  
Ute A. Schwinghammer ◽  
Magda M. Melkonyan ◽  
Lilit Hunanyan ◽  
Roman Tremmel ◽  
Ralf Weiskirchen ◽  
...  
Keyword(s):  
Growth Factor ◽  
Liver Fibrosis ◽  
Liver Injury ◽  
Transforming Growth Factor ◽  
Smooth Muscle Actin ◽  
Transforming Growth Factor Β ◽  
Liver Sinusoidal Endothelial Cells ◽  
Mediated Effects ◽  
Liver Sinusoids ◽  
Endothelial Nitric Oxide

The noradrenergic system is proposed to play a prominent role in the pathogenesis of liver fibrosis. While α1- and β-adrenergic receptors (ARs) are suggested to be involved in a multitude of profibrogenic actions, little is known about α2-AR-mediated effects and their expression pattern during liver fibrosis and cirrhosis. We explored the expression of α2-AR in two models of experimental liver fibrosis. We further evaluated the capacity of the α2-AR blocker mesedin to deactivate hepatic stellate cells (HSCs) and to increase the permeability of human liver sinusoidal endothelial cells (hLSECs). The mRNA of α2a-, α2b-, and α2c-AR subtypes was uniformly upregulated in carbon tetrachloride-treated mice vs the controls, while in bile duct-ligated mice, only α2b-AR increased in response to liver injury. In murine HSCs, mesedin led to a decrease in α-smooth muscle actin, transforming growth factor-β and α2a-AR expression, which was indicated by RT-qPCR, immunocytochemistry, and Western blot analyses. In a hLSEC line, an increased expression of endothelial nitric oxide synthase was detected along with downregulated transforming growth factor-β. In conclusion, we suggest that the α2-AR blockade alleviates the activation of HSCs and may increase the permeability of liver sinusoids during liver injury.

scholarly journals Angiotensin-Converting Enzyme 2 as a Possible Correlation between COVID-19 and Periodontal Disease

2020 ◽  
Vol 10 (18) ◽  
pp. 6224 ◽  
Author(s):  
Leonardo Mancini ◽  
Vincenzo Quinzi ◽  
Stefano Mummolo ◽  
Giuseppe Marzo ◽  
Enrico Marchetti
Keyword(s):  
Angiotensin Ii ◽  
Inflammatory Response ◽  
Angiotensin Converting Enzyme ◽  
Transforming Growth Factor ◽  
Tissue Injury ◽  
Interleukin 2 ◽  
Converting Enzyme ◽  
Angiotensin Converting Enzyme 2 ◽  
Cell Functions

SARS-CoV-2 propagation in the world has led to rapid growth and an acceleration in the discoveries and publications of various interests. The main focus of a consistent number of studies has been the role of angiotensin-converting enzyme 2 (ACE2) in binding the virus and its role in expression of the inflammatory response after transmission. ACE2 is an enzyme involved in the renin–angiotensin system (RAS), whose key role is to regulate and counter angiotensin-converting enzyme (ACE), reducing the amount of angiotensin II and increasing angiotensin 1–7 (Ang1–7), making it a promising drug target for treating cardiovascular diseases. The classical RAS axis, formed by ACE, angiotensin II (Ang II), and angiotensin receptor type 1 (AT1), activates several cell functions and molecular signalling pathways related to tissue injury and inflammation. In contrast, the RAS axis composed of ACE2, Ang1–7, and Mas receptor (MasR) exerts the opposite effect concerning the inflammatory response and tissue fibrosis. Recent studies have shown the presence of the RAS system in periodontal sites where osteoblasts, fibroblasts, and osteoclasts are involved in bone remodelling, suggesting that the role of ACE2 might have a fundamental function in the under- or overexpression of cytokines such as interleukin-6 (IL-6), interleukin-7 (IL-7), tumour necrosis factor alpha (TNF-α), interleukin-2 (IL-2), interleukin-1 beta (IL-1β), monocyte chemoattractant protein-1 (MCP-1), and transforming growth factor-beta (TGF-β), associated with a periodontal disorder, mainly during coinfection with SARS-CoV-2, where ACE2 is underexpressed and cannot form the ACE2–Ang1–7–MasR axis. This renders the patient unresponsive to an inflammatory process, facilitating periodontal loss.

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