This website uses cookies to ensure you have the best experience. Learn more

Degradation Of The Liver By Matrix Metalloproteinases

1111 words - 5 pages

Matrix metalloproteinases (MMPs) are the enzymes responsible for matrix degradation in the liver [38]. These are calcium-dependent enzymes that specifically degrade collagens and noncollagenous substrates. MMPs are divided into 5 categories according to their substrate [39]:

1) interstitial collagenases (MMP-1, -8, -13),
2) gelatinases (MMP-2,-9, and fibroblast activation protein),
3) stromelysins (MMP-3, -7, -10, -11),
4) membrane type (MMP-14, -15, -16, -17, -24, -25), and
5) metalloelastase (MMP-12).

The degradation of normal extracellular matrix (ECM) is a key event in the process of liver fibrosis as it allows its replacement with scar matrix. Activated HSCs secrete large amounts of MMP-2 and MMP-9, which degrade the collagen type IV of normal ECM [40]. They also express large amounts of MMP-1 mRNA, the principal MMP which degrades scar matrix (predominantly collagen type I), however little active enzyme is detectable in fibrotic liver [40]. Tissue inhibitors of matrix metalloproteinases (TIMPs) are the main regulators (inhibitors) of MMP activity. HSCs produce large amounts of TIMP-1 and TIMP-2 and these prevent the degradation of the interstitial collagens of scar matrix by MMP-1[41]. TIMP-1 also promotes HSC survival [42, 43].

Loss of Retinoids
A characteristic feature of stellate cell activation is the loss of retinoid (Vitamin A) droplets from the perinuclear region. The exact role that this plays in the transition from the quiescent to activated phenotype remains unclear.

1.2.2 Alternative Sources of Myofibroblasts
Recently it has been recognized that myofibroblasts are derived from a number of sources other than the quiescent HSC population. These sources include portal fibroblasts, circulating fibrocytes and the bone marrow. Epithelial-mesenchymal transformation (EMT) of both hepatocytes and cholangiocytes was also thought to contribute to the myofibroblast population however lineage tracing studies in experimental models of liver fibrosis have shown that this does not occur [44, 45]. EMT may, however, still play a role in malignant transformation and invasion in advanced injury.

a) Portal Fibroblasts
Myofibroblasts may also derive from portal fibroblasts found in the connective tissue surrounding blood vessels and the biliary tree [46] and these are thought to play a particularly important role in biliary fibrosis [47-49]. Beaussier et al [47] have shown that HSCs do not undergo myofibroblastic differentiation in biliary fibrosis and that portal myofibroblasts are the major contributors to the myofibroblast population in this form of injury. The portal myofibroblast population was initially identified as distinct from HSCs by their different growth characteristics in culture. Portal myofibroblasts can be subcultured several times whereas activated HSCs quickly undergo apoptosis [48, 50]. These observations aided in the identification of distinct gene-expression profiles which differentiate the two cell types. Both HSCs...

Find Another Essay On Degradation of the Liver by Matrix Metalloproteinases

The Matrix and the Allegory of the Cave by Plato

775 words - 3 pages The Matrix and the cave There are numerous similarities between The Matrix and “The Allegory of the Cave” by Plato. “The Allegory of the Cave” has prisoners of the cave that are unable to move and only able to see what passes over their cave and there is one prisoner that is freed (Plato, circa 380 BC). The Matrix has humans trapped inside of the matrix. (Silver Pictures & Wachowski Brothers, 1999). The main character is Neo. Neo represents the

The Degradation of Human Relationships in Fahrenheit 451, by Ray Bradbury

997 words - 4 pages communication is important and can be even considered necessary, even though our technology continues to advance. There are multiple examples of the degradation of human relationships found in Fahrenheit 451. These examples range from simple seashell radios, which are comparable to in-ear headphones, to a television set that spans over an entire wall, and also interacts with you as if it were human. If you take a look around you as you’re

The Degradation of Communication on the Internet

5448 words - 22 pages The Degradation of Communication on the Internet Talking on the Internet, people regress. It's that simple. It can be one-to-one talk on e-mail or many-to-many talk on one of the LISTs or newsgroups. People regress, expressing sex and aggression as they never would face to face. Think about it. Current estimates say 23 million people communicate on the Internet from most of the nations on the globe, and that number is increasing at 12

The Degradation of Music for Mass Consumption

3003 words - 12 pages The Degradation of Music for Mass Consumption From the very first time that someone decided to experiment with a musical tradition, the cry has gone out that "true," "pure," and "good" music is dead to society, and that music itself is on a perpetual slide to oblivion. All apostrophe aside, this is a serious matter to consider. Music inhabits a significant place in all cultures. Musical style is very much a function of the Zeitgeist

Philosophy Of The Matrix

1289 words - 5 pages did.The Wachowskis introduced us to Thomas A. / Neo Anderson, played by Keanu Reeves, in the beginning of the film. They made it a point to have their viewers know that Keanu had both an everyday life name of Thomas, and a hacker name of Neo. This duel personality that is given to Keanu is foreshadowing his move out of the matrix and into the apocalyptical world known as reality. Since an artificially intelligent computer runs the matrix, it realized

Philosophy of the Matrix

1399 words - 6 pages perceived. For example, when something is too good to be true, it usually is, as there are unforeseen obstacles that one must deal with in order to reach the goal or to get what they want. The reality, in effect, is something much harder to understand. The movie proves this by relating Zion to a form of what is real with profound skepticism mixed with logic. What is perceived while in “The Matrix” is in reality, a deception to entangle and confuse

Sophie's Matrix - a philosophical overview of Sophie's World by Jostein Gaarder in cojuction with the film The Matrix

1174 words - 5 pages breaking free presents not only positive but also negative elements. When Sophie decided to continue the philosophy course, she left the "red glasses" behind and ventured into a different world. This is one of the multiple parallels between Sophie's World and the film The Matrix. There is an obvious correlation between Sophie and Neo as characters in a world governed by another, more powerful force. In the Matrix, Alberto's role is taken on by

The Role of Vitamin D in Liver Disease

898 words - 4 pages Over the years, the role of vitamin D in chronic liver disease has been studied by many scientists. Some research shows that chronic liver disease leads to vitamin D deficiency but many studies also show that low vitamin D levels may lead to liver disease. What is Vitamin D? Vitamin D is a fat-soluble substance that is synthesized in the skin during exposure to sunlight. This is why it is often called the sunshine vitamin. Although it is

Primary atypical carcinoid tumor of the liver: A case report

816 words - 4 pages form of increased mitotic activity and nuclear hyperchromasia (Fig. 5). The neuroendocrine feature was identified by immunohistochemical markers such as synaptophysin (Fig. 6) and chromogranin. DISCUSSION Atypical carcinoid tumor of liver is not a common clinical practice. Female cases are four times more than male. Usually patient present with upper abdominal distention and pain. At the time of admission to the hospital hepatomegaly has been

The Philosophy of the Matrix

1125 words - 5 pages , by the end of The Matrix believes in his duty as the One, and vows to save the human race from ignorance and artificial intelligence rather than let them live in deception, essentially "free [the] mind" (NEO, The Wachowski Brothers, 125). The Matrix ends with a protagonist and hope of a enlightenment for the human race, whereas Plato's Allegory of the Cave depicts a bleaker future. Neo embracing the role of being the One defines The Matrix and

Analysis of Film The Matrix

2410 words - 10 pages footage to show speed and action, fashioning the extremes that the Matrix will hold. In places this was filmed using slow motion but some parts of the film needed to be done in 'bullet time photography.' This involved using computers and many cameras in different positions all set at different times. The complexity of using bullet time is shown by the fact that it uses almost 12 000 frames a second! The Matrix uses

Similar Essays

The Degradation Of Hiphop Essay

2554 words - 10 pages form of MCing, which is only one-fourth of Hiphop - definitely not enough to define what Hiphop is. Still, the corporate media glamorizes gangster rap and uses it as a marketing tool to sell products, then labels them “Hiphop.” In today’s society, Hiphop has become extremely marketable and is used to sell everything from sneakers to liquor to dolls. I’m waiting for the day that a song written about Bacardi liquor – paid for by Bacardi – makes it

Degradation Of The Coral Reefs Essay

1098 words - 4 pages from waves, careless tourists, and destructive fishers. Coral reefs are threatened by rising levels of carbon dioxide in the atmosphere; this lowers the rate of coral by up to 10 to 20 percent as carbon dioxide levels double up in the next century. This will make it harder for the coral to build up their skeletons and add to the reef.Scientists have identified pollution as one of the leading causes of coral reef degradation. This threat comes from a

The Media's Degradation Of Women Essay

2928 words - 12 pages to blame for that. For decades, the media has dominated society’s views and perspectives of others. Due to recent media, it has been difficult to regulate how women are being influenced and treated by other people in society. The media influences society tremendously and subconsciously steers the way we treat and think of others. Advertisements, television shows, movies, the internet, magazines and other forms of the media have all targeted women

The Cause And Effects Of Liver Failure

756 words - 3 pages in the digestion of fats.Disease is also controlled by the liver. Infections which arise in the intestine are kept at bay by the liver.With the liver playing such an important role in fighting so many diseases, and functioning on a complex level, it is no wonder that liver failure is so serious.Liver failure can result from any type of liver disorder, injury, or disease. The liver can suffer complete failure from alcohol, Ecstasy, or one of many