scholarly journals Lymphatics and Lymphangiogenesis in the Eye

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Shintaro Nakao ◽  
Ali Hafezi-Moghadam ◽  
Tatsuro Ishibashi

Lymphatic is a prerequisite for the maintenance of tissue fluid balance and immunity in the body. A body of evidence also shows that lymphangiogenesis plays important roles in the pathogenesis of diseases such as tumor metastasis and inflammation. The eye was thought to lack lymphatic vessels except for the conjunctiva; however, advances in the field, including the identification of lymphatic endothelial markers (e.g., LYVE-1 or podoplanin) and lymphangiogenic factors (e.g., VEGF-C), have revealed the exsitence and possible roles of lymphatics and lymphangiogenesis in the eye. Recent studies have shown that corneal limbus, ciliary body, lacrimal gland, orbital meninges, and extraocular muscles contain lymphatic vessels and that the choroid might have a lymphatic-like system. There is no known lymphatic outflow from the eye. However, several lymphatic channels including uveolymphatic pathway might serve the ocular fluid homeostasis. Furthermore, lymphangiogenesis plays important roles in pathological conditions in the eye including corneal transplant rejection and ocular tumor progression. Yet, the role of lymphangiogenesis in most eye diseases, especially inflammatory disease or edema, remains unknown. A better understanding of lymphatic and lymphangiogenesis in the eye will open new therapeutic opportunities to prevent vision loss in ocular diseases.

2020 ◽  
Vol 6 (50) ◽  
pp. eabc2697
Author(s):  
Kim Pin Yeo ◽  
Hwee Ying Lim ◽  
Chung Hwee Thiam ◽  
Syaza Hazwany Azhar ◽  
Caris Tan ◽  
...  

A functional lymphatic vasculature is essential for tissue fluid homeostasis, immunity, and lipid clearance. Although atherosclerosis has been linked to adventitial lymphangiogenesis, the functionality of aortic lymphatic vessels draining the diseased aorta has never been assessed and the role of lymphatic drainage in atherogenesis is not well understood. We develop a method to measure aortic lymphatic transport of macromolecules and show that it is impaired during atherosclerosis progression, whereas it is ameliorated during lesion regression induced by ezetimibe. Disruption of aortic lymph flow by lymphatic ligation promotes adventitial inflammation and development of atherosclerotic plaque in hypercholesterolemic mice and inhibits ezetimibe-induced atherosclerosis regression. Thus, progression of atherosclerotic plaques may result not only from increased entry of atherogenic factors into the arterial wall but also from reduced lymphatic clearance of these factors as a result of aortic lymph stasis. Our findings suggest that promoting lymphatic drainage might be effective for treating atherosclerosis.


PARADIGMI ◽  
2009 ◽  
pp. 71-83
Author(s):  
Jean-Jacques Wunenburger

- Linguistic Sedimentation, and Bodily Inscription At present, we are exposed to an excessive offer of images, which raises a problem of assimilation. Subjects are increasingly passive, in ways that can border on pathological conditions. Yet, it is not so much a question of condemning this situation as of finding a way of re-symbolizing images, saving them from mere contemplation and inserting them in a process of contextualisation. Such a process requires an understanding of the role of the body and of the incorporation of images along the lines of Bachelard's intuition of the "resisting" nature of images. This raises the possibility of an education to images suited to the present age.Key words: Alienation, Education, Embodiment, Image, Informatics, Symbolisation.Parole chiave: Alienazione, Educazione, Immagine, Incorporazione, Informatica, Simbolizzazione.


1978 ◽  
Vol 234 (1) ◽  
pp. H52-H58
Author(s):  
E. P. Salathe ◽  
R. Venkataraman

A mathematical model of capillary-tissue fluid exchange is presented. The effect of variation in plasma and interstitial osmotic pressure that occurs as a result of convection and diffusion of protein is examined. Analytic solutions to the resulting equations are obtained by using the methods of perturbation theory. It is found that fluid exchange can significantly alter the pericapillary interstitial osmotic pressure, reducing both filtration and reabsorption. Variation in plasma osmotic pressure is important only for certain pathological conditions in which excessive filtration occurs. Specific numerical examples are presented which show quantitatively the extent of these effects for various normal and pathological conditions of physiological interest.


2012 ◽  
Vol 302 (11) ◽  
pp. R1235-R1249 ◽  
Author(s):  
Sara Stridh ◽  
Fredrik Palm ◽  
Peter Hansell

The glycosaminoglycan (GAG) hyaluronan (HA) is recognized as an important structural component of the extracellular matrix, but it also interacts with cells during embryonic development, wound healing, inflammation, and cancer; i.e., important features in normal and pathological conditions. The specific physicochemical properties of HA enable a unique hydration capacity, and in the last decade it was revealed that in the interstitium of the renal medulla, where the HA content is very high, it changes rapidly depending on the body hydration status while the HA content of the cortex remains unchanged at very low amounts. The kidney, which regulates fluid balance, uses HA dynamically for the regulation of whole body fluid homeostasis. Renomedullary HA elevation occurs in response to hydration and during dehydration the opposite occurs. The HA-induced alterations in the physicochemical characteristics of the interstitial space affects fluid flux; i.e., reabsorption. Antidiuretic hormone, nitric oxide, angiotensin II, and prostaglandins are classical hormones/compounds involved in renal fluid handling and are important regulators of HA turnover during variations in hydration status. One major producer of HA in the kidney is the renomedullary interstitial cell, which displays receptors and/or synthesis enzymes for the hormones mentioned above. During several kidney disease states, such as ischemia-reperfusion injury, tubulointerstitial inflammation, renal transplant rejection, diabetes, and kidney stone formation, HA is upregulated, which contributes to an abnormal phenotype. In these situations, cytokines and other growth factors are important stimulators. The immunosuppressant agent cyclosporine A is nephrotoxic and induces HA accumulation, which could be involved in graft rejection and edema formation. The use of hyaluronidase to reduce pathologically overexpressed levels of tissue HA is a potential therapeutic tool since diuretics are less efficient in removing water bound to HA in the interstitium. Although the majority of data describing the role of HA originate from animal and cell studies, the available data from humans demonstrate that an upregulation of HA also occurs in diabetic kidneys, in transplant-rejected kidneys, and during acute tubular necrosis. This review summarizes the current knowledge regarding interstitial HA in the role of regulating kidney function during normal and pathological conditions. It encompasses mechanistic insights into the background of the heterogeneous intrarenal distribution of HA; i.e., late nephrogenesis, its regulation during variations in hydration status, and its involvement during several pathological conditions. Changes in hyaluronan synthases, hyaluronidases, and binding receptor expression are discussed in parallel.


F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 1197
Author(s):  
Morgan K. Groover ◽  
Jillian M. Richmond

Chemokines play important roles in homeostasis and inflammatory processes. While their roles in leukocyte recruitment are well-appreciated, chemokines play additional roles in the body, including mediating or regulating angiogenesis, tumor metastasis and wound healing. In this opinion article, we focus on the role of CXCR3 and its ligands in fibrotic processes. We emphasize differences of the effects of each ligand, CXCL9, CXCL10 and CXCL11, on fibroblasts in different tissues of the body. We include discussions of differences in signaling pathways that may account for protective or pro-fibrotic effects of each ligand in different experimental models and ex vivo analysis of human tissues. Our goal is to highlight potential reasons why there are disparate findings in different models, and to suggest ways in which this chemokine axis could be manipulated for the treatment of fibrosis.


Author(s):  
Paulina Niedźwiedzka-Rystwej ◽  
Dominika Bębnowska ◽  
Roman Kołacz ◽  
Wiesław Deptuła

Research on the health of mammals invariably shows how dynamic immunology is and how the role of many elements and immune processes of the macroorganism, developed in the process of evolution in protecting against threats, including infections, is changing. Among these elements conditioning the homeostasis of the macroorganism are mitochondria, PRR receptors (pattern recognition receptors) and the phenomenon of autophagy. In the context of physiological and pathological states in the body, mitochondria perform various functions. The primary function of these organelles is to produce energy in the cell, but on the other hand, they are heavily involved in various cellular processes, including ROS production and calcium homeostasis. They are largely involved in the activation of immune mechanisms during infectious and non-infectious conditions through mtDNA and the mitochondrial MAVS protein. Mitochondrial involvement has been also determined in PRR-related mechanisms as mtDNA has the ability to directly stimulate TLRs. On the other hand, mitochondria are also associated with apoptotic cell death and autophagy.


2021 ◽  
Vol 10 ◽  
Author(s):  
Aukie Hooglugt ◽  
Miesje M. van der Stoel ◽  
Reinier A. Boon ◽  
Stephan Huveneers

Solid tumors are dependent on vascularization for their growth. The hypoxic, stiff, and pro-angiogenic tumor microenvironment induces angiogenesis, giving rise to an immature, proliferative, and permeable vasculature. The tumor vessels promote tumor metastasis and complicate delivery of anti-cancer therapies. In many types of tumors, YAP/TAZ activation is correlated with increased levels of angiogenesis. In addition, endothelial YAP/TAZ activation is important for the formation of new blood and lymphatic vessels during development. Oncogenic activation of YAP/TAZ in tumor cell growth and invasion has been studied in great detail, however the role of YAP/TAZ within the tumor endothelium remains insufficiently understood, which complicates therapeutic strategies aimed at targeting YAP/TAZ in cancer. Here, we overview the upstream signals from the tumor microenvironment that control endothelial YAP/TAZ activation and explore the role of their downstream targets in driving tumor angiogenesis. We further discuss the potential for anti-cancer treatments and vascular normalization strategies to improve tumor therapies.


2021 ◽  
Vol 18 (3) ◽  
pp. 336-344
Author(s):  
V. V. Klimontov ◽  
D. M. Bulumbaeva

The lymphatic system (LS) is one of the main integrative systems of the body, providing protective and transport functions. In recent years, interactions between LS and adipose tissue (AT) have been of particular interest. Lymphatic vessels play an important role in metabolic and regulatory functions of AT, acting as a collector of lipolysis products and adipokines. In its turn, hormones and adipocytokines that produced in adipocytes (including leptin, adiponectin, IL-6, TNF-α, etc.) affect the function of lymphatic endothelial cells and control the growth of lymphatic vessels. Cooperation between LS and AT becomes pathogenetically and clinically important in lymphedema and obesity. It is known that both primary and secondary lymphedema are characterized by increased fat accumulation which is associated with the severity of lymphostasis and inflammation. Similarly, in obesity, the drainage function of LS is impaired, which is accompanied by perilymphatic mononuclear infiltration in the AT. The development of these changes is facilitated by endocrine dysfunction of adipocytes and impaired production of adipocytokines. The increase in the production of inflammatory mediators and the disruption of the traffic of inflammatory cells causes a further deterioration in the outflow of interstitial fluid and exacerbates the inflammation of the AT, thereby forming a vicious circle. The role of lymphangiogenesis in AT remodeling in obesity needs further research. Another promising area of research is the study of the role of intestinal LS in the development of obesity and related disorders. It has been shown that the transport of chylomicrons from the intestine depends on the expression of a number of molecular mediators (VEGF-C, DLL-4, neuropilin-1, VEGFR-1, CD36/FAT, etc.)in the endotheliocytes of the intestinal lymphatic vessels, as well as the functioning of «push-button» and “zippering” junctions between endothelial cells. New approach to the treatment of obesity based on blockade of lymphatic chylomicrontransport has been experimentally substantiated. Further identification of the molecular mechanisms and signaling pathways that determine the remodeling of AT in lymphedema and obesity are likely to provide new approaches to the treatment of these diseases.


2019 ◽  
pp. 328-349
Author(s):  
Pavel Pavlovich Zagoskin

The principal possibility of nonspecific energy expenditure at all stages of the transformation of nutrients in the body is demonstrated. These stages include the processing of food in the mouth, digestion, absorption, interaction with the intestinal micro biome, and interstitial metabolic processes. Particular attention is paid to the role of nonspecific energy expenditure of the body in the regulation of body mass. The data on the pivotal role of reducing nonspecific energy expenditure in the development of obesity and associated pathological conditions are presented. The prospects for using uncouples of oxidative phosphorylation, fatty acids, carnitine, bile acids, sarcolipin and a number of other substances as regulators of the nonspecific energy expenditure and potential means of preventing and treating obesity are analyzed.


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