| Articles from Dr. Chikly Hyaluronan The term hyaluronan (HA) has lately substituted the terms hyaluronic acid and hyaluronate Only one kind of hyaluronan exists, in the classical form of glycosaminoglycan. The highest concentration of HA is found in the soft connective tissue, about half of it in the dermis and epidermis, and also in the vitreous body of the eye, in hyaline cartilage, in synovial joint fluid, blood vessels and in the umbilical cord. Until recently however, HA was considered to be an inert space filler that bind water molecules and fulfilled mainly a mechanical roles in the human tissues. - Under gradual shear stress, hyaluronan acts as a lubricant - Under sudden loading, hyaluronan acts as a shock absorber - Hyaluronan acts as a filter, hindering the movement of potentially damaging cells and molecules Recently, HA has been also demonstrated to 1- Facilitate cell adhesion (hyaluronan interact specifically with cell receptors such as CD 44, RHAMM, ICAM-1). Cell anchored hyaluronan meshworks can prevent cells, particles and large molecules from approaching closely to the cell membrane. 2- Modulate acute and chronic tissue inflammation processes both in animals and human beings. HA has a half-life of about a day. It is principally degraded in the lymph nodes. As much as 80-90% of HA is transported in afferent lymphatics vessels to the lymph nodes for final degradation. Only about 15 % is transported to the blood circulation to be catatabolized in the liver endothelium. In both cases, macrophage-like cells intertwined with the endothelial cells degrade hyaluronan. In lymphedematous tissue, especially when lymph nodes has been removed, the concentration of HA increase in the regional tissues. HA is usually "trapped" in lymphedematous tissues. One of the earliest known properties of HA is to bind water and increase edematous state in tissue. Local breakdown of HA (rather than in the nodes) produce also components that induce inflammation (release cytokines from macrophages), influence collagen and fibrin production and help induce fibrotic processes in lymphedema. In the future, we will hear probably more and more about the role of HA in edema |
| general chapter on management of lymphedema While Lymph Drainage Therapy is appropriate therapy for many diseases, in a book like this lymphedema inevitably stands out. It is the condition in connection with which the most scientific research has been done on the therapeutic use of lymphatic drainage; it is particularly difficult to comprehend and challenging to treat; and while it is unfortunately very widespread, understanding of it and education and training about it are gravely deficient on the part of the general public, practitioners and physicians alike. My own training in medical school unfortunately taught me very little about the condition, its diagnosis and treatment. Furthermore, the condition is characterized by its disabling and far-reaching effects. Not only can lymphedema disable the patient, but it tends to get worse over time if untreated and can lead to serious and recurring complications. It seems appropriate to devote a large section of this book to lymphedema and its treatment, especially its multifaceted, conservative treatment called complex decongestive physiotherapy (CDP). This term refers to a combination of modalities, including manual and compressive therapies, which is usually the first treatment to consider in lymphedema. Lymphedema it tends to respond to this kind of appropriate conservative treatment. CDP is safe, non invasive, effective and cost effective, but must be applied by trained and skilled practitioners. In some syndromes where high output lymphatic transport failure is longstanding, a gradual functional deterioration of the draining lymphatics may supervene and thereby reduce overall transport capacity. A reduced lymphatic circulatory capacity then develops in the face of increased blood capillary filtration. Examples include recurring infection, thermal burns, and repeated allergic reactions. These latter conditions are associated with "safety valve insufficiency" of the lymphatic system and can be considered a mixed form of edema/lymphedema and as such are particularly troublesome to treat................ From "Consensus Document of the International Society of Lymphology, The Diagnosis and Treatment of Peripheral Lymphedema, Lymphology, 2003 June, 36, (2): 84-91. Reproduced here by kind permission |
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