The Unique biology of lymphatic edema

The Unique biology of lymphatic edema

Lymphat Res Biol. 2009

Rockson SG.

Stanford Center for Lymphatic and Venous Disorders, Stanford University School of Medicine, Stanford, California 94305, USA. srockson@cvmed.stanford.edu

Sadly, the subject of lymphatic vascular insufficiency continues to engender relative neglect by health care professionals, which represents a source of frustration and fear among patients. A re-consideration of the unique, complex biology of lymphatic vascular disorders has the capacity both to reinvigorate interest and facilitate the implementation of the correct, existing treatment interventions for individuals affected by these disease states. While most of this complex lymphatic biology remains somewhat elusive, growing insights into the molecular mechanisms of lymphatic development and repair have been instructive. Present and future considerations in lymphedema diagnosis and management must acknowledge the unique tissue biology of this disorder. Many changes are unique to the lymphatic mechanisms of chronic edema. The profound stimulus to collagen deposition in the integument seems to be unique to chronic lymphatic edema, although this biology remains largely unexplicated. Several lines of evidence also suggest that lymphatic function has a unique and important influence upon adipose biology. Molecular investigation of murine models of human acquired lymphedema are beginning to shed light on these processes. Such focused mechanistic, approaches to the study of lymphedema and other lymphatic diseases are vital, as we attempt to expand our insights into the complex biology of lymphedema and its potential responsiveness to pharmacologic control and molecular intervention, prevention, and reversal.

MaryAnnLiebert

Contractile Physiology of Lymphatics

Contractile Physiology of Lymphatics

Lymphat Res Biol. 2009

Zawieja DC.

Department of Systems Biology and Translational Medicine, Cardiovascular Research Institute Division of Lymphatic Biology, Texas A&M Health Science Center College of Medicine, Temple, Texas 77843-1114, USA.

The lymphatic system has important roles in body fluid regulation, macromolecular homeostasis, lipid absorption, and immune function. To accomplish these roles, lymphatics must move fluid and its other contents (macromolecules, lipids/chylomicra, immune cells) from the interstitium through the lymphatics, across the nodes, and into the great veins. Thus, the principal task of the lymphatic vascular system is transport.

The body must impart energy to the lymph via pumping mechanisms to propel it along the lymphatic network and use pumps and valves to generate lymph flow and prevent its backflow. The lymphatic system utilizes both extrinsic pumps, which rely on the cyclical compression and expansion of lymphatics by surrounding tissue forces, and intrinsic pumps, which rely on the intrinsic rapid/phasic contractions of lymphatic muscle.

The intrinsic lymph pump function can be modulated by neural, humoral, and physical factors. Generally, increased lymph pressure/stretch of the muscular lymphatics activates the intrinsic lymph pump, while increased lymph flow/shear in the muscular lymphatics can either activate or inhibit the intrinsic lymph pump depending on the pattern and magnitude of the flow. To regulate lymph transport, lymphatic pumping and resistance must be controlled.

A better understanding of these mechanisms could provide the basis for the development of better diagnostic and treatment modalities for lymphatic dysfunction.

MaryAnnLiebert

Vascular Malformations: an update

Vascular Malformations: an update

Perspect Vasc Surg Endovasc Ther. 2009 Jun

Gloviczki P, Duncan A, Kalra M, Oderich G, Ricotta J, Bower T, McKusick M, Bjarnason H,Driscoll D.

Division of Vascular and Endovascular Surgery and Vascular Malformation Clinic, Gonda Vascular Center, Mayo Clinic, Rochester, MN, USA. gloviczki.peter@mayo.edu , Division of Vascular and Interventional Radiology, Mayo Clinic, Rochester, MN, USA, Vascular Malformation Clinic, Gonda Vascular Center, mayo Clinic, Rochester, MN, USA, Division of Vascular and Endovascular Surgery, Gonda Vascular Center, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.

Vascular malformations occur as a result of an arrest in the development of the vascular system. The modified Hamburg classification distinguishes arterial, venous, arteriovenous, capillary, lymphatic, and mixed vascular malformations. Each malformation is further subdivided based on anatomy and on the time when arrest in development of the embryogenesis occurred; malformations can be truncular or extratruncular. Progress in the last decade in management has been significant because of improvements in open surgical procedures and perfection of percutaneous and hybrid endovascular interventions and devices, such as balloons, stents, and stent-grafts. There has been increasing use of embolization for the treatment of malformations with coils, other particles, glue, or with endovascular placement of occlusive plugs. Absolute alcohol, detergent liquids, or foam have been used for sclerotherapy with improved efficacy. The agents are delivered percutaneously or through a catheter placed either into the feeding arteries or the draining veins. This review aims to aid vascular and endovascular specialists in staying familiar with vascular malformations. These specialists need to be able to evaluate the patients, perform treatment if appropriate, or refer complex cases to multidisciplinary vascular malformation clinics and vascular centers.

Sage Publications

SoxF genes: Key players in the development of the cardio-vascular system.

SoxF genes: Key players in the development of the cardio-vascular system

Francois M, Koopman P, Beltrame M.

Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld 4072, Australia.

SoxF genes (Sox7, Sox17 and Sox18) encode a group of transcription factors that have a pivotal role in cardio-vascular development. SOXF factors orchestrate endothelial cell fate or direct cell differentiation in developing heart, blood vessels and lymphatic vessels. Their roles are highly conserved throughout animal evolution. SOXF activity is finely tuned with a variety of cell type-specific co-factors and partner proteins to effect transcription of genes critical for endothelial cell phenotype and function. Because SOXF factors play a central role in cardiogenesis, vasculogenesis and lymphangiogenesis, SOXF gene mutations figure prominently in the aetiology of human vascular disease.

Wiley InterScience

Lymphatic Development

Lymphatic Development

Birth Defects Res C Embryo Today. 2009 Sep 11

Butler MG, Isogai S, Weinstein BM.

Laboratory of Molecular Genetics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892.

email: Brant M. Weinstein (bw96w@nih.gov)

The lymphatic system is essential for fluid homeostasis, immune responses, and fat absorption, and is involved in many pathological processes, including tumor metastasis and lymphedema. Despite its importance, progress in understanding the origins and early development of this system has been hampered by lack of defining molecular markers and difficulties in observing lymphatic cells in vivo and performing genetic and experimental manipulation of the lymphatic system. Recent identification of new molecular markers, new genes with important functional roles in lymphatic development, and new experimental models for studying lymphangiogenesis has begun to yield important insights into the emergence and assembly of this important tissue. This review focuses on the mechanisms regulating development of the lymphatic vasculature during embryogenesis. Birth Defects Research (Part C)

Wiley InterScience

Intrauterine Treatment of Large Fetal Neck Lymphangioma with OK-432.

Intrauterine Treatment of Large Fetal Neck Lymphangioma with OK-432.

Fetal Diagn Ther. 2009 Sep 11

Mikovic Z, Simic R, Egic A, Stosic Opincal T, Koprivsek K, Stanojevic D, Bogavac M, Popovac M, Mandic V.
Department of High-Risk Pregnancies, University Clinic of Gynaecology and Obstetrics 'Narodni Front', Belgrade, Serbia.

Lymphangiomas are benign vascular malformations of the lymphatic system and most commonly present in the neck area. Large lymphangiomas may compress and/or displace the larynx, trachea and esophagus and cause serious respiratory and feeding problems in neonates. Prenatal therapy could eliminate the risks of the mentioned complications. Prenatal therapy may include the EXIT (ex utero intrapartum treatment) procedure. As this procedure has certain risks for both the neonate and mother, the introduction of a safer method is justified. The use of OK-432, as a sclerosing agent, has shown positive results in several published cases of cystic hygroma, but there is no study about the prenatal use of this agent in the treatment of lymphangioma. The aim of this study was to present our experience with intrauterine intralesional injection of OK-432 in the treatment of neck lymphangiomas. Two cases of large multicystic neck lymphangiomas that were closely situated to the fetal airway were treated by single intralesional injection of OK-432. We noticed a progressive decrease in tumor volume throughout gestation. We did not experience any complications and there were no respiratory or feeding problems in the neonates. The esthetical appearance was satisfactory and both children were normal at the age of 2 years and 6 months, respectively. This report suggests that prenatal intralesional injection of OK-432 might be a safe and effective treatment in selected cases with large fetal neck lymphangiomas.

Fetal Diagnosis and Therapy

Case report of fetal axillo-thoraco-abdominal cystic hygroma.

Case report of fetal axillo-thoraco-abdominal cystic hygroma.

Arch Gynecol Obstet. 2009 Apr 10

Masood SN, Masood MF.
Dow University of Health Sciences, Karachi, Pakistan, sh_naz@yahoo.com.

Cystic hygroma (moist tumor) was first described in 1828 by Redenbacher. The cyst usually results owing to an absence or an inefficient connection between the lymphatic and venous systems. Of this type of malformation 75% cases are localized in the nuchal region; however, only 20% are found in the axilla while 5% of these hygromas are in other locations. Prognosis depends on associated fetal co-morbidities. There are many case reports on cystic hygroma but only a few on the axillo-thoraco-abdominal variant. This is a case report of a huge late-onset fetal axillo-thoraco-abdominal cystic hygroma, which was diagnosed at term followed by a difficult vaginal delivery in a 38-year-old woman. The baby did not have any congenital anomaly other than cystic hygroma with no evidence of intrathoracic or intra-abdominal extension of mass and a pelvic kidney reported on neonatal ultrasound and CT scan. The surgical excision of the cyst was done on the fourth day following birth and the histopathology report confirmed the diagnosis. Management of fetal cystic hygroma with the use of a sclerosing agent is a new modality being explored. Risk of recurrence in subsequent pregnancies for aneuploidy is not increased. The baby has been followed up to 5 months of birth and is thriving well. Karyotype shows an XX pattern.

SpringerLink