Pathogenesis of Intestinal Amebiasis: From Molecules to Disease

2000 ◽  
Vol 13 (2) ◽  
pp. 318-331 ◽  
Author(s):  
Martha Espinosa-Cantellano ◽  
Adolfo Martínez-Palomo
Keyword(s):  
Immune Response ◽  
Polymorphonuclear Leukocytes ◽  
Molecular Mechanisms ◽  
Acute Infection ◽  
Human Colon ◽  
Histological Findings ◽  
Lytic Lesions ◽  
Extracellular Matrix Components ◽  
Matrix Components ◽  
Intestinal Amebiasis

SUMMARY In spite of a wealth of knowledge on the biochemistry and cellular and molecular biology of Entamoeba histolytica, little has been done to apply these advances to our understanding of the lesions observed in patients with intestinal amebiasis. In this review, the pathological and histological findings in acute amebic colitis are related to the molecular mechanisms of E. histolytica pathogenicity described to date. Infection of the human colon by E. histolytica produces focal ulceration of the intestinal mucosa, resulting in dysentery (diarrhea with blood and mucus). Although a complete picture has not yet been achieved, the basic mechanisms involved in the production of focal lytic lesions include complex multifactorial processes in which lectins facilitate adhesion, proteases degrade extracellular matrix components, porins help nourish the parasite and may also kill incoming polymorphonuclear leukocytes and macrophages, and motility is used by the parasite to invade deeper layers of the colon. In addition, E. histolytica has developed mechanisms to modulate the immune response during acute infection. Nevertheless, much still needs to be unraveled to understand how this microscopic parasite has earned its well-deserved histolytic name.

scholarly journals What are the markers of aggressiveness in prolactinomas? Changes in cell biology, extracellular matrix components, angiogenesis and genetics

2007 ◽  
Vol 156 (2) ◽  
pp. 143-153 ◽  
Author(s):  
Alper Gürlek ◽  
Niki Karavitaki ◽  
Olaf Ansorge ◽  
John A H Wass
Keyword(s):  
Extracellular Matrix ◽  
Cell Adhesion ◽  
Growth Factor ◽  
Molecular Mechanisms ◽  
Cellular Migration ◽  
Tumour Suppressor Genes ◽  
Suprasellar Region ◽  
Extracellular Matrix Components ◽  
Matrix Components ◽  
E Cadherin

Prolactinoma is the most common pituitary tumour in adults. Macroprolactinomas, particularly in men, may occasionally exhibit a very aggressive clinical course as evidenced by progressive growth, invasion through bone into the sphenoid sinus, cavernous sinus, suprasellar region or the nasopharynx. Some may even progress to pituitary carcinoma with craniospinal or systemic metastases. Aggressive tumours have low cure rates despite appropriate medical and surgical treatment. The mechanisms underlying this aggressive biological behaviour have not yet been fully clarified. Recent immunohistochemical, molecular and genetic studies have provided some insight in this respect. Invasive prolactinomas may be associated with a high Ki-67/MIB-1 labelling index indicating increased cell proliferation, although this is not a universal finding. The AA polymorphism in the cyclin adenine (A)/guanine (G) gene is more frequently detected in invasive prolactinomas. Increased expression of the polysialylated neural cell adhesion molecule (NCAM) and reduced expression of the E-cadherin/catenin complex implies a contribution of altered cell-to-cell adhesion and cellular migration. Extracellular matrix components (ECM), matrix metalloproteinases (MMPs) and their inhibitors play important roles in the context of angiogenesis and invasion. The induction of fibroblast growth factor and vascular endothelial growth factor via oestrogen-induced overexpression of novel genes (PTTG, hst and Edpm5) enhance cell growth, proliferation and angiogenesis contributing to invasiveness in prolactinomas. Although mutations in proto-oncogenes like Ras are uncommon, loss of tumour suppressor genes at loci 11q13, 13q12–14, 10q and 1p seem to be associated with invasiveness. Of the described mechanisms, only reduced E-cadherin/catenin expression and overexpression of hst gene seem to be relatively specific markers for prolactinoma invasiveness compared with other pituitary adenomas. Further research is needed to clarify the molecular mechanisms behind the aggressive course of some prolactinomas to predict those with a potentially poor clinical outcome, and to devise treatments that will eventually enable the cure of these challenging tumours.

scholarly journals Fighting against Skin Aging

2018 ◽  
Vol 27 (5) ◽  
pp. 729-738 ◽  
Author(s):  
Shoubing Zhang ◽  
Enkui Duan
Keyword(s):  
Molecular Mechanisms ◽  
Treatment Strategies ◽  
Skin Aging ◽  
The Body ◽  
Aging Research ◽  
Functional Changes ◽  
Extracellular Matrix Components ◽  
Matrix Components ◽  
Aging Factors ◽  
Outer Environment

As the most voluminous organ of the body that is exposed to the outer environment, the skin suffers from both intrinsic and extrinsic aging factors. Skin aging is characterized by features such as wrinkling, loss of elasticity, laxity, and rough-textured appearance. This aging process is accompanied with phenotypic changes in cutaneous cells as well as structural and functional changes in extracellular matrix components such as collagens and elastin. In this review, we summarize these changes in skin aging, research advances of the molecular mechanisms leading to these changes, and the treatment strategies aimed at preventing or reversing skin aging.

scholarly journals LOXL2—A New Target in Antifibrogenic Therapy?

2019 ◽  
Vol 20 (7) ◽  
pp. 1634 ◽  
Author(s):  
Angela Puente ◽  
Jose Fortea ◽  
Joaquin Cabezas ◽  
Maria Arias Loste ◽  
Paula Iruzubieta ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Liver Fibrosis ◽  
Animal Studies ◽  
Molecular Mechanisms ◽  
Lysyl Oxidase ◽  
Portal Pressure ◽  
Induce Cell Cycle Arrest ◽  
Cell Functions ◽  
Extracellular Matrix Components ◽  
Matrix Components

The concept of liver fibrosis and cirrhosis being static and therefore irreversible is outdated. Indeed, both human and animal studies have shown that fibrogenesis is a dynamic and potentially reversible process that can be modulated either by stopping its progression and/or by promoting its resolution. Therefore, the study of the molecular mechanisms involved in the pathogenesis of liver fibrosis is critical for the development of future antifibrotic therapies. The fibrogenesis process, common to all forms of liver injury, is characterized by the increased deposition of extracellular matrix components (EMCs), including collagen, proteoglycans, and glycoproteins (laminin and fibronectin 2). These changes in the composition of the extracellular matrix components alter their interaction with cell adhesion molecules, influencing the modulation of cell functions (growth, migration, and gene expression). Hepatic stellate cells and Kupffer cells (liver macrophages) are the key fibrogenic effectors. The antifibrogenic mechanism starts with the activation of Ly6Chigh macrophages, which can differentiate into macrophages with antifibrogenic action. The research of biochemical changes affecting fibrosis irreversibility has identified lysyl oxidase-like 2 (LOXL2), an enzyme that promotes the network of collagen fibers of the extracellular matrix. LOXL2 inhibition can decrease cell numbers, proliferation, colony formations, and cell growth, and it can induce cell cycle arrest and increase apoptosis. The development of a new humanized IgG4 monoclonal antibody against LOXL2 could open the window of a new antifibrogenic treatment. The current therapeutic target in patients with liver cirrhosis should focus (after the eradication of the causal agent) on the development of new antifibrogenic drugs. The development of these drugs must meet three premises: Patient safety, in non-cirrhotic phases, down-staging or at least stabilization and slowing the progression to cirrhosis must be achieved; whereas in the cirrhotic stage, the objective should be to reduce fibrosis and portal pressure.

Molecular Mechanisms of Mural Thrombosis Under Dynamic Flow Conditions

Physiology ◽  
1995 ◽  
Vol 10 (3) ◽  
pp. 117-122
Author(s):  
JM Ross ◽  
LV McIntire
Keyword(s):  
Myocardial Infarction ◽  
Molecular Mechanisms ◽  
Fluid Dynamic ◽  
Blood Platelets ◽  
Flow Conditions ◽  
Dynamic Flow ◽  
Platelet Surface ◽  
Surface Receptors ◽  
Extracellular Matrix Components ◽  
Matrix Components

Mural adhesion and aggregation of blood platelets are crucial for hemostasis but in pathological situations can lead to myocardial infarction and stroke. The specific platelet surface receptors employed are determined by the local fluid dynamic conditions and extracellular matrix components exposed at the site of a vascular wound.

Biomineralization of Enamel and Dentin Mediated by Matrix Proteins

2021 ◽  
pp. 002203452110184
Author(s):  
J. Moradian-Oldak ◽  
A. George
Keyword(s):  
Extracellular Matrix ◽  
Protein Interactions ◽  
Molecular Mechanisms ◽  
Tooth Enamel ◽  
Organic Matrix ◽  
Biomechanical Properties ◽  
Protein Matrix ◽  
Noncollagenous Proteins ◽  
Extracellular Matrix Components ◽  
Matrix Components

Biomineralization of enamel, dentin, and bone involves the deposition of apatite mineral crystals within an organic matrix. Bone and teeth are classic examples of biomaterials with unique biomechanical properties that are crucial to their function. The collagen-based apatite mineralization and the important function of noncollagenous proteins are similar in dentin and bone; however, enamel is formed in a unique amelogenin-containing protein matrix. While the structure and organic composition of enamel are different from those of dentin and bone, the principal molecular mechanisms of protein–protein interactions, protein self-assembly, and control of crystallization events by the organic matrix are common among these apatite-containing tissues. This review briefly summarizes enamel and dentin matrix components and their interactions with other extracellular matrix components and calcium ions in mediating the mineralization process. We highlight the crystallization events that are controlled by the protein matrix and their interactions in the extracellular matrix during enamel and dentin biomineralization. Strategies for peptide-inspired biomimetic growth of tooth enamel and bioinspired mineralization of collagen to stimulate repair of demineralized dentin and bone tissue engineering are also addressed.

Dynamics of T Cells Repertoire During Trypanosoma cruzi Infection and its Post-Treatment Modulation

2019 ◽  
Vol 26 (36) ◽  
pp. 6519-6543 ◽  
Author(s):  
Adriana Egui ◽  
Paola Lasso ◽  
Elena Pérez-Antón ◽  
M. Carmen Thomas ◽  
Manuel Carlos López
Keyword(s):  
Immune Response ◽  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Cardiac Tissue ◽  
Acute Infection ◽  
Clinical Status ◽  
Chronic Phase ◽  
Parasite Load ◽  
Chronic Patients ◽  
Cruzi Infection

Chagas disease courses with different clinical phases and has a variable clinical presentation and progression. The acute infection phase mostly exhibits a non-specific symptomatology. In the absence of treatment, the acute phase is followed by a chronic phase, which is initially asymptomatic. This chronic asymptomatic phase of the disease is characterized by a fragile balance between the host’s immune response and the parasite replication. The loss of this balance is crucial for the progression of the sickness. The virulence and tropism of the T. cruzi infecting strain together to the inflammation processes in the cardiac tissue are the main factors for the establishment and severity of the cardiomyopathy. The efficacy of treatment in chronic Chagas disease patients is controversial. However, several studies carried out in chronic patients demonstrated that antiparasitic treatment reduces parasite load in the bloodstream and leads to an improvement in the immune response against the Trypanosoma cruzi parasite. The present review is mainly focused on the cellular patterns associated to the clinical status and the evolution of the disease in chronic patients, as well as the effectiveness of the treatment related to T. cruzi infection control. Therefore, an emphasis is placed on the dynamics of specific-antigens T cell subpopulations, their memory and activation phenotypes, their functionality and their contribution to pathogenesis or disease control, as well as their association with risk of congenital transmission of the parasite.

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