Diagnosis and management of lymphatic vascular disease

Development of the lymphoedema genito-urinary cancer questionnaire

The aim of this study was to develop a patient self-report tool to detect symptoms of genital and lower limb lymphoedema in male survivors of genitourinary cancer. The study incorporated the views of patients and subject specialists (lymphoedema and urology) in the design of a patient questionnaire based on the literature. Views on comprehensiveness, relevance of content, ease of understanding and perceived acceptability to patients were collated. The findings informed the development of the next iteration of the questionnaire. The overall view of participants was that the development and application of such a tool was of great clinical value and the Lymphoedema Genito-Urinary Cancer Questionnaire (LGUCQ) has significant potential for further development as a research tool to inform prevalence of this under-reported condition.

Selected case from the Arkadi M. Rywlin international pathology slide series: lymphangiomatosis of the spleen associated with ipsilateral abdominopelvic and lower extremity venolymphatic malformations: a case report and review of the literature

Herein, we report a 26-year-old patient with lymphangiomatosis of the spleen associated with multiple lymphatic and venous malformations. This patient underwent excision of a large lymphatic malformation of the left abdominal wall during childhood. A venous malformation of her left lower limb was excised during adolescence. Additional lymphatic malformations were found in the soft tissue of her left thigh at the age of 20. During hospitalization for a huge vulvar hemangioma at the age of 26, she was incidentally found to have asymptomatic splenomegaly, for which she underwent splenectomy. Examination of the spleen revealed diffuse involvement by a lymphatic anomaly predominantly forming small cystic spaces. Lymphangiomatosis of the spleen is rare and is classically separated into an isolated or pure form and a generalized form when it is associated with involvement of other viscera and/or multiple soft-tissue planes. This patient was affected by a borderline form of splenic lymphangiomatosis with limited somatic involvement of the superficial soft tissues and blood vessels. Notably, all the additional vascular malformations in this patient were left sided, and at this time there was no additional involvement of internal organ. No hereditary or known syndrome was identified.

Human podoplanin-positive monocytes and platelets enhance lymphangiogenesis through the activation of the podoplanin/CLEC-2 axis

Emerging studies suggested that murine podoplanin-positive monocytes (PPMs) are involved in lymphangiogenesis. The goal of this study was to demonstrate the therapeutic lymphangiogenesis of human PPMs by the interaction with platelets. Aggregation culture of human peripheral blood mononuclear cells (PBMCs) resulted in cellular aggregates termed hematospheres. During 5-day culture, PPMs expanded exponentially and expressed several lymphatic endothelial cell-specific markers including vascular endothelial growth factor receptor (VEGFR)-3 and well-established lymphangiogenic transcription factors. Next, we investigated the potential interaction of PPMs with platelets that had C-type lectin-like receptor-2 (CLEC-2), a receptor of podoplanin. In vitro coculture of PPMs and platelets stimulated PPMs to strongly express lymphatic endothelial markers and upregulate lymphangiogenic cytokines. Recombinant human CLEC-2 also stimulated PPMs through Akt and Erk signaling. Likewise, platelets in coculture with PPMs augmented secretion of a lymphangiogenic cytokine, interleukin (IL)-1-β, via podoplanin/CLEC-2 axis. The supernatant obtained from coculture was able to enhance the migration, viability, and proliferation of lymphatic endothelial cell. Local injection of hematospheres with platelets significantly increased lymphatic neovascularization and facilitated wound healing in the full-thickness skin wounds of nude mice. Cotreatment with PPMs and platelets augments lymphangiogenesis through podoplanin/CLEC-2 axis, which thus would be a promising novel strategy of cell therapy to treat human lymphatic vessel disease.

Kampo Extract of Shinbuto Improved Refractory Diarrhea in Milroy's Disease

Milroy's disease is a hereditary congenital lymphedema caused by lymphatic obstruction. The legs are most commonly affected, but impaired intestinal lymphatic flow can cause loose bowel movements. Here, we report the use of the Kampo extract of shinbuto for successful treatment of and abdominal pain in a patient with Milroy's disease. Milroy's disease was diagnosed because of left leg lymph-edema with onset at birth. Conservative therapy with a compression bandage was applied. However, when the patient moved to Manila at 35 years of age, she was exposed to drastic temperature changes between the air-conditioned cold environment in her room and the hot and humid environment outside. She developed a constitutional state of coldness as in hiesho (冷え症). Then sudden lower abdominal pain and diarrhea began to occur 3 times per week and lasted at least 1 hour, sometimes accompanied by vomiting. It happened particularly when she was exposed to the cold environment and was not related to meals. Conventional anti-cholinergic or antidiarrhetic drugs had no therapeutic effect. These attacks continued in the same frequency for 3 years, so the patient visited a Kampo (traditional Japanese medicine) clinic, where her diagnosis of Milroy's disease–associated diarrhea and abdominal pain was augmented by the Kampo diagnosis of hiesho, suitai (body fluid retention). She was prescribed 7.5 g of shinbuto extract per day (TJ-30; Tsumura Co, Tokyo, Japan). The shinbuto extract significantly reduced abdominal pain and refractory diarrhea to about 2 days per month, and it tapered off completely in 3 months. Shinbuto is usually used against cold-induced diarrhea. Rewarming and water movement by shinbuto resulted in significant improvement in symptoms induced by hiesho and suitai triggered by the cold environment, though the patient's leg swelling did not change.

Breast and gynecologic cancer-related extremity lymphedema: a review of diagnostic modalities and management options

Lymphedema remains a poorly understood entity that can occur after lymphadenectomy. Herein, we will review the pathogenesis of lymphedema, diagnostic modalities and the natural history of extremity involvement. We will review the incidence of upper extremity lymphedema in patients treated for breast malignancies and lower extremity lymphedema in those treated for gynecologic malignancy. Finally, we will review traditional treatment modalities for lymphedema, as well as introduce new surgical treatment modalities that are under active investigation.

Differential transport function of lymphatic vessels in the rat tail model and the long-term effects of Indocyanine Green as assessed with near-infrared imaging

Introduction: Near-infrared (NIR) imaging has emerged as a novel imaging modality for assessing lymphatic function in vivo. While the technique has provided quantitative data previously unavailable, questions remain in regards to the spatiotemporal capabilities of the approach. We address three of the more important issues here using the rodent tail, one of the most widely utilized in vivo model systems in the lymphatic literature. Specifically we demonstrate (1) the transient vs. steady state response of lymphatics to tracer injection, (2) the functional characteristics of multiple collecting vessels draining the same tissue space in parallel, and (3) the long-term consequences of fluorescent tracers on lymphatic function to repeated functional measurements.

Methods: Rat tails were imaged with NIR and metrics of function were calculated for both collecting vessels that drain the tail. A nitric oxide donor cream (GTNO) was applied to the tail. Additionally, two different NIR dyes, indocyanine green (ICG) and LI-COR IRDye 800CW PEG, were utilized for function imaging at the time of initial injection and at 1, 2, and 4 week follow-up time points after which both draining lymph nodes were harvested.

Results and Discussion: Significant differences were found between the two collecting vessels such that the vessel first showing fluorescence (dominant) produced enhanced functional metrics compared to the second vessel (non-dominant). GTNO significantly reduced lymphatic function in the non-dominant vessel compared to the dominant. ICG remained visible in the tail for 2 weeks after injection and was accompanied by significant losses in lymphatic function and enlarged draining lymph nodes. The Licor tracer also remained visible for 2 weeks. However, the dye produced significantly lower effects on lymphatic function than ICG, and lymph nodes were not enlarged at any time point, suggesting that this may be a more appropriate contrast agent for longitudinal lymphatic imaging.

Adrenomedullin haploinsufficiency predisposes to secondary lymphedema

Secondary lymphedema is a debilitating condition, and genetic factors predisposing to its development remain largely unknown. Adrenomedullin (AM) is peptide encoded, together with proadrenomedullin N-terminal peptide (PAMP), by the Adm gene (adrenomedullin gene). AM and its putative receptor calcitonin receptor-like receptor (CLR) are implicated in angiogenesis and lymphangiogenesis during embryogenesis and wound healing, suggesting their possible involvement in secondary lymphedema. To investigate whether AM deficiency predisposes to secondary lymphedema, we used heterozygous adult mice with Adm gene-knockin stop mutation, which selectively abrogated AM, but preserved PAMP, expression (Adm(AM+/Δ) animals). After hind limb skin incision, Adm messenger RNA expression was upregulated in wounded tissue of both Adm(AM+/+) and Adm(AM+/Δ) mice. However, only Adm(AM+/Δ) animals developed limb swelling and histopathological lymphedematous changes, including epidermal thickening, elevated collagen fiber density, and increased microvessel diameter. Secondary lymphedema was prevented when circulating AM levels in Adm(AM+/Δ) mice were restored by systemic peptide delivery. In human skin, CLR was expressed in tissue components affected by lymphedema, including epidermis, lymphatics, and blood vessels. Our study identified a previously unrecognized role for endogenous AM as a key factor in secondary lymphedema pathogenesis and provided experimental in vivo evidence of an underlying germ-line genetic predisposition to developing this disorder.

Bone morphogenetic protein 9 (BMP9) controls lymphatic vessel maturation and valve formation

Lymphatic vessels are critical for the maintenance of tissue fluid homeostasis and their dysfunction contributes to several human diseases. The activin receptor-like kinase 1 (ALK1) is a transforming growth factor-β family type 1 receptor that is expressed on both blood and lymphatic endothelial cells (LECs). Its high-affinity ligand, bone morphogenetic protein 9 (BMP9), has been shown to be critical for retinal angiogenesis. The aim of this work was to investigate whether BMP9 could play a role in lymphatic development. We found that Bmp9 deficiency in mice causes abnormal lymphatic development. Bmp9-knockout (KO) pups presented hyperplastic mesenteric collecting vessels that maintained LYVE-1 expression. In accordance with this result, we found that BMP9 inhibited LYVE-1 expression in LECs in an ALK1-dependent manner. Bmp9-KO pups also presented a significant reduction in the number and in the maturation of mesenteric lymphatic valves at embryonic day 18.5 and at postnatal days 0 and 4. Interestingly, the expression of several genes known to be involved in valve formation (Foxc2, Connexin37, EphrinB2, and Neuropilin1) was upregulated by BMP9 in LECS. Finally, we demonstrated that Bmp9-KO neonates and adult mice had decreased lymphatic draining efficiency. These data identify BMP9 as an important extracellular regulator in the maturation of the lymphatic vascular network affecting valve development and lymphatic vessel function.

Molecular mechanisms and imaging of lymphatic metastasis

In many types of cancer, tumors metastasize through the lymphatic system to draining lymph nodes. These sentinel lymph nodes have gained increased attention as a prognostic indicator for the severity of the disease, leading to the sentinel lymph node mapping and biopsy procedure to be accepted as standard-of-care for breast cancer and melanoma. However, many limitations exist with this procedure resulting in high false negative rates. In this review we highlight the new advances in the understanding of the molecular mechanisms of lymphangiogenesis and tumor metastasis that may lead to improved strategies in the detection of the sentinel lymph nodes and therapeutic interventions to prevent further tumor spread. In addition, advances in imaging technology are allowing new approaches for anatomical mapping of lymphatic drainage patterns and molecular imaging strategies that may improve detection of metastatic tumor cells within sentinel lymph nodes.

Blood vessel hyperpermeability and pathophysiology in human tumour xenograft models of breast cancer: a comparison of ectopic and orthotopic tumours

BACKGROUND

Human tumour xenografts in immune compromised mice are widely used as cancer models because they are easy to reproduce and simple to use in a variety of pre-clinical assessments. Developments in nanomedicine have led to the use of tumour xenografts in testing nanoscale delivery devices, such as nanoparticles and polymer-drug conjugates, for targeting and efficacy via the enhanced permeability and retention (EPR) effect. For these results to be meaningful, the hyperpermeable vasculature and reduced lymphatic drainage associated with tumour pathophysiology must be replicated in the model. In pre-clinical breast cancer xenograft models, cells are commonly introduced via injection either orthotopically (mammary fat pad, MFP) or ectopically (subcutaneous, SC), and the organ environment experienced by the tumour cells has been shown to influence their behaviour.

METHODS

To evaluate xenograft models of breast cancer in the context of EPR, both orthotopic MFP and ectopic SC injections of MDA-MB-231-H2N cells were given to NOD scid gamma (NSG) mice. Animals with matched tumours in two size categories were tested by injection of a high molecular weight dextran as a model nanocarrier. Tumours were collected and sectioned to assess dextran accumulation compared to liver tissue as a positive control. To understand the cellular basis of these observations, tumour sections were also immunostained for endothelial cells, basement membranes, pericytes, and lymphatic vessels.

RESULTS

SC tumours required longer development times to become size matched to MFP tumours, and also presented wide size variability and ulcerated skin lesions 6 weeks after cell injection. The 3 week MFP tumour model demonstrated greater dextran accumulation than the size matched 5 week SC tumour model (for P < 0.10). Immunostaining revealed greater vascular density and thinner basement membranes in the MFP tumour model 3 weeks after cell injection. Both the MFP and SC tumours showed evidence of insufficient lymphatic drainage, as many fluid-filled and collagen IV-lined spaces were observed, which likely contain excess interstitial fluid.

CONCLUSIONS

Dextran accumulation and immunostaining results suggest that small MFP tumours best replicate the vascular permeability required to observe the EPR effect in vivo. A more predictable growth profile and the absence of ulcerated skin lesions further point to the MFP model as a strong choice for long term treatment studies that initiate after a target tumour size has been reached.

Update on the biology and treatment of lymphedema

OPINION STATEMENT

The past decade has produced an explosion of insights into lymphatic vascular development and structural biology and, in parallel, into the function of the lymphatics in health and in disease. In lymphedema, there is a spectrum that extends from primary (heritable) to acquired causes of disease. The diagnosis of lymphatic edema implicates a very specific treatment approach that is predicated upon the favorable impact of physiotherapy upon lymph flow and protein clearance from the edematous zones of the body. The recognition of the unique biology that accompanies lymphatic causes of edema has stimulated new research directions that are likely to translate into exciting new pharmacologic and molecular approaches to diagnosis and treatment.

Characteristics of multi-organ lymphangiectasia resulting from temporal deletion of calcitonin receptor-like receptor in adult mice

Adrenomedullin (AM) and its receptor complexes, calcitonin receptor-like receptor (Calcrl) and receptor activity modifying protein 2/3, are highly expressed in lymphatic endothelial cells and are required for embryonic lymphatic development. To determine the role of Calcrl in adulthood, we used an inducible Cre-loxP system to temporally and ubiquitously delete Calcrl in adult mice. Following tamoxifen injection, Calcrl^fl/fl/CAGGCre-ER™ mice rapidly developed corneal edema and inflammation that was preceded by and persistently associated with dilated corneoscleral lymphatics. Lacteals and submucosal lymphatic capillaries of the intestine were also dilated, while mesenteric collecting lymphatics failed to properly transport chyle after an acute Western Diet, culminating in chronic failure of Calcrl^fl/fl/CAGGCre-ER™ mice to gain weight. Dermal lymphatic capillaries were also dilated and chronic edema challenge confirmed significant and prolonged dermal lymphatic insufficiency. In vivo and in vitro imaging of lymphatics with either genetic or pharmacologic inhibition of AM signaling revealed markedly disorganized lymphatic junctional proteins ZO-1 and VE-cadherin. The maintenance of AM signaling during adulthood is required for preserving normal lymphatic permeability and function. Collectively, these studies reveal a spectrum of lymphatic defects in adult Calcrl^fl/fl/CAGGCre-ER™ mice that closely recapitulate the clinical symptoms of patients with corneal, intestinal and peripheral lymphangiectasia.

Vascular anomalies: from genetics toward models for therapeutic trials

Vascular anomalies are localized abnormalities that occur during vascular development. Several causative genes have been identified not only for inherited but also for some sporadic forms, and the molecular pathways involved are becoming understood. This gives us the opportunity to generate animals carrying the causative genetic defects, which we hope model the phenotype seen in human patients. These models would enable us not only to test known antiangiogenic drugs, but also to develop novel approaches for treatment, directly targeting the mutated protein or molecules implicated in the pathophysiological signaling pathways.

Current views on diagnostic approach and treatment of lymphedema

Lymphedema is a chronic, progressive, and often debilitating condition. Primary lymphedema is a lymphatic malformation developing during the later stage of lymphangiogenesis. Secondary lymphedema is the result of obstruction or disruption of the lymphatic system, which can occur as a consequence of tumors, surgery, trauma, infection, inflammation, and radiation therapy. In this review, we report an update upon the diagnostic approach and the medical and surgical therapy for both primary and secondary lymphedema.

Endothelial progenitor cell transplantation decreases lymphangiogenesis and adverse myocardial remodeling in a mouse model of acute myocardial infarction

Cardiac lymphatic system in the remodeling after acute myocardial infarction (AMI) has been overlooked. We wanted to investigate the role of bone marrow-derived endothelial progenitor cells (EPCs) and their contribution to lymphatic distribution in myocardial remodeling after AMI. Mouse (C57bl/6J) MI models were created by ligation of the left anterior descending coronary artery and were treated with phosphate buffered saline (PBS) or EPCs. Real-time RT-PCR with 2- to 4-week myocardial tissue samples revealed that lymphangiogenetic factors such as vascular endothelial growth factor (VEGF)-C (8.5 fold, P < 0.05), VEGF-D (6.1 fold, P < 0.05), Lyve-1 (15 fold, P < 0.05), and Prox-1 (11 fold, P < 0.05) were expressed at significantly higher levels in the PBS group than the EPC group. The PBS group also showed a significantly higher density of lymphatic vessels in the peri-infarction area. Echocardiography showed that from 2 weeks after the treatment, left ventricle (LV) dimensions at both systole and diastole were significantly smaller in the EPC group than in the PBS group (P < 0.01) and LV fractional shortening was higher in the EPC group accordingly (P < 0.01). Lymphangiogenic markers increased in a mouse MI model. EPC transplantation decreased lymphangiogenesis and adverse ventricular remodeling after AMI. These novel findings suggest that new lymphatic vessels may be formed in severely damaged myocardium, and may be involved in adverse myocardial remodeling after AMI.

Lymphedema: a therapeutic approach in the treatment and rehabilitation of cancer patients

Lymphedema therapy has gone by many names in the recent past, being referred to as complex decongestive therapy, complex physical therapy, or decongestive lymphatic therapy, among others. There are two phases of lymphedema treatment: the acute "intensive" phase and the maintenance phase. In the acute phase of treatment, the individual is typically wrapped with medical short-stretch compression bandages; receives a therapeutic exercise routine, skin care, and education; and undergoes manual lymphatic drainage by a specially trained physical therapist or healthcare professional. In the maintenance phase, the goals are for the individual to be able to wear a well-fitted appropriate gradient pressure garment during the day and compression bandaging (or a device that serves as an alternative to bandaging) at night, to maintain good skin care, to continue with therapeutic exercise, and to self-perform manual lymphatic drainage (or use a mechanical device that can perform manual lymphatic drainage) for the area of the body with impaired lymphatics. The effectiveness of the various components in each phase, as well as the motivation and compliance of the patient, differs. Further randomized trials are required to determine which component or combination of components in complex decongestive therapy works most effectively. It is recommended for patients not only to maintain physical activity for its many health benefits but also to facilitate muscle pumping to move lymphatic fluid throughout the body. Knowledge of some of the pathophysiologic mechanisms involved in the development of lymphedema is increasing, and it is possible that current modes of treatment of lymphedema will be augmented by molecular therapies in the future.

The Transcriptional Control of Lymphatic Vascular Development

More than 100 years ago, Florence Sabin suggested that lymphatic vessels develop by sprouting from preexisting blood vessels, but it is only over the past decade that the molecular mechanisms underpinning lymphatic vascular development have begun to be elucidated. Genetic manipulations in mice have identified a transcriptional hub comprised of Prox1, CoupTFII, and Sox18 that is essential for lymphatic endothelial cell fate specification. Recent work has identified a number of additional transcription factors that regulate later stages of lymphatic vessel differentiation and maturation. This review highlights recent advances in our understanding of the transcriptional control of lymphatic vascular development and reflects on efforts to better understand the activities of transcriptional networks during this discrete developmental process. Finally, we highlight the transcription factors associated with human lymphatic vascular disorders, demonstrating the importance of understanding how the activity of these key molecules is regulated, with a view toward the development of innovative therapeutic avenues.

Late effects of breast cancer treatment and potentials for rehabilitation

BACKGROUND

Breast cancer is the most frequent malignant disease among women world wide. Survival has been improving leading to an increasing number of breast cancer survivors, in the US estimated to about 2.6 million.

MATERIAL AND METHODS

The literature was reviewed with focus on data from the Nordic countries.

RESULTS

Local therapies such as breast cancer surgery and radiotherapy may cause persistent pain in the breast area, arm, and shoulder reported by 30-50% of patients after three to five years, lymphedema in 15-25% of patients, and restrictions of arm and shoulder movement in 35%. Physiotherapy is the standard treatment for the latter while no pain intervention trials have been published. Chemotherapy may cause infertility and premature menopause, resulting in vasomotor symptoms, sexual dysfunction, and osteoporosis, which are similar to the side effects of endocrine treatment in postmenopausal women. Awareness of cardiotoxicity is needed since anthracyclines, trastuzumab, and radiotherapy can damage the heart. Breast cancer survivors have an increased risk of a major depression and far from all receive adequate anti-depressive treatment. Other psychological symptoms include fear of recurrence, sleep disturbances, cognitive problems, fatigue, and sexual problems.

DISCUSSION

To improve rehabilitation, specific goals have to be formulated into national guidelines and high priority directed towards research into developing and testing new interventions for alleviating symptoms and side effects experienced by breast cancer survivors.

Assessment of volume measurement of breast cancer-related lymphedema by three methods: circumference measurement, water displacement, and dual energy X-ray absorptiometry

BACKGROUND

Following treatment for breast cancer 12%-60% develop breast cancer-related lymphedema (BCRL). There are several ways of assessing BCRL. Circumference measurement (CM) and water displacement (WD) for volume measurements (VM) are frequently used methods in practice and research, respectively. The aim of this study was to evaluate CM and WD for VM of the BCRL arm and the contralateral arm, comparing the results with regional dual energy X-ray absorptiometry (DXA).

METHODS AND RESULTS

Twenty-four women with unilateral BCRL were included in the study. Blinded duplicate VM were obtained from both arms using the three methods mentioned above. CM and DXA were performed by two observers. WD was performed by a group of observers. Mean differences (d) in duplicated volumes, limits of agreement (LOA), and 95% confidence intervals (CI) were calculated for each method. The repeatability expressed as d (95% CI) between the duplicated VM of the BCRL arm and the contralateral arm was for DXA 3 ml (-6-11) and 3 ml (1-7), respectively. For CM and WD, the d (95% CI) of the BCRL arm were 107 ml (86-127) and 26 ml (-26-79), respectively and in the contralateral arm 100 ml (78-122) and -6 ml (-29-17), respectively.

CONCLUSIONS

DXA is superior in repeatability when compared to CM and WD for VM, especially for the BCRL arm but also the contralateral arm.

Zebrafish provides a novel model for lymphatic vascular research

The mammalian lymphatic vasculature has an important function in the maintenance of tissue fluid homeostasis, absorption of dietary lipids, and immune surveillance. The lymphatic vessels are also recruited by many tumors as primary routes for metastasis and mediate immune responses in inflammatory diseases, whereas dysfunction of the lymphatic drainage leads to lymphedema. The characterization of a lymphatic vasculature in zebrafish has made the advantages of this small model organism, the suitability for intravital time-lapse imaging of developmental processes and the amenability for chemical and forward genetic screens, available to lymphatic vascular research. Here we review our current understanding of embryonic lymphangiogenesis in zebrafish, its molecular and anatomical similarities to mammalian lymphatic vascular development, and the possibilities zebrafish offers to complement mouse models and cell culture assays in the lymphangiogenesis field.

Causes and consequences of lymphatic disease

The visceral manifestations of lymphatic disorders (lymphangiomatosis and lymphangiectasia) are particularly severe. Any pathology of the lymphatic vasculature, whether superficial or internal, regional, or systemic, is predominated by the appearance of lymphedema, the characteristic form of tissue edema that occurs when lymphatic dysfunction supervenes. Disease manifestations may include dysregulation of body fluid homeostasis, immune traffic impairment, and disturbances of lipid and protein reabsorption from the gut lumen. The appearance of lymphatic edema invokes complex biological alterations. Many of these changes seem to relate uniquely to chronic lymphatic edema, including a profound stimulus to collagen and adipose deposition. Despite the recent advances in our understanding of these disorders, substantial knowledge gaps remain; these gaps inhibit our ability to accurately identify, categorize, treat, and prevent these diseases. Future diagnostic, therapeutic, and reproductive decisions for affected individuals require an accurate knowledge of the clinical and laboratory presentation, mode of inheritance, treatment response, outcomes, and prognosis.

Current concepts and future directions in the diagnosis and management of lymphatic vascular disease

Despite the central, complex role for the lymphatic system in the maintenance of human health, the biology of this important and complex vasculature has been relatively under-investigated. However, the last decade has witnessed a substantial growth in the elucidation of lymphatic structural biology and the function of this system in health and in disease. These newly gained insights can be used to formulate our evolving concepts about the diagnostic and therapeutic approaches to patients with lymphatic vascular disorders. In lymphedema, there is a spectrum of disease that extends from primary (heritable) to secondary (acquired) causes. Once detected, the presence of lymphatic edema mandates very specific modalities of intervention, predominated by physiotherapeutic techniques. In addition, a physiological basis for adjunctive, intermittent pneumatic compression has been established, and these modalities may be indicated in selected patient populations. The acknowledgement of a unique biology in lymphatic edemas is, increasingly, guiding research efforts within this field. Increasing investigative attention is being directed toward animal models of lymphatic vascular disease. As insight into the complex biology of the lymphatic vasculature continues to expand through focused biomedical investigation, the translation of these mechanistic insights into targeted, rationally conceived therapeutics will become increasingly feasible.

Balancing lymphedema risk: exercise versus deconditioning for breast cancer survivors

Lymphedema, a common and feared negative effect of breast cancer treatment, is generally described by arm swelling and dysfunction. Risk averse clinical recommendations guided survivors to avoid the use of the affected arm. This may lead to deconditioning and, ironically, the very outcome women seek to avoid. Recently published studies run counter to these guidelines.

Primary lymphoedema and lymphatic malformation: are they the two sides of the same coin?

OBJECTIVES

To clear the confusion regarding the relationship between the 'primary lymphoedema' and (truncular) lymphatic malformation (LM); the latter is one of congenital vascular malformations.

MATERIALS & METHODS

A literature review was carried out on the primary lymphoedema either existing as an independent LM lesion or as a component of the Klippel-Trenaunay syndrome.

RESULTS

The review was able to provide a contemporary guide/conclusion on the definition and classification, clinical evaluation and clinical management regarding conservative (physical) therapy, reconstructive surgical therapy and ablative/excisional surgical therapy, for the primary lymphoedema as an LM.

CONCLUSIONS

Primary lymphoedema can be considered as 'congenital' since its majority represents a clinical manifestation of the truncular type of LM arising during the later stages of lymphangiogenesis. Such embryological staging information of the LM is critical for proper management of the primary lymphoedema when it exists with other congenital vascular malformations (Klippel-Trenaunay syndrome). 2. Basic non-invasive to minimally invasive tests will provide an adequate diagnosis and lead to the correct multidisciplinary, specifically targeted and sequenced treatment strategy. 3. The mainstay of current management of the primary lymphoedema/truncular LM is complex decongestive therapy; and the reconstructive as well as ablative surgical therapy remain adjunctive therapies at best.

Dermal collagen and lipid deposition correlate with tissue swelling and hydraulic conductivity in murine primary lymphedema

Primary lymphedema is a congenital pathology of dysfunctional lymphatic drainage characterized by swelling of the limbs, thickening of the dermis, and fluid and lipid accumulation in the underlying tissue. Two mouse models of primary lymphedema, the Chy mouse and the K14-VEGFR-3-Ig mouse, both lack dermal lymphatic capillaries and exhibit a lymphedematous phenotype attributable to disrupted VEGFR-3 signaling. Here we show that the differences in edematous tissue composition between these two models correlated with drastic differences in hydraulic conductivity. The skin of Chy mice possessed significantly higher levels of collagen and fat, whereas K14-VEGFR-3-Ig mouse skin composition was relatively normal, as compared with their respective wild-type controls. Functionally, this resulted in a greatly increased dermal hydraulic conductivity in K14-VEGFR3-Ig, but not Chy, mice. Our data suggest that lymphedema associated with increased collagen and lipid accumulation counteracts an increased hydraulic conductivity associated with dermal swelling, which in turn further limits interstitial transport and swelling. Without lipid and collagen accumulation, hydraulic conductivity is increased and overall swelling is minimized. These opposing tissue responses to primary lymphedema imply that tissue remodeling--predominantly collagen and fat deposition--may dictate tissue swelling and govern interstitial transport in lymphedema.

Anti-inflammatory pharmacotherapy with ketoprofen ameliorates experimental lymphatic vascular insufficiency in mice

Background

Disruption of the lymphatic vasculature causes edema, inflammation, and end-tissue destruction. To assess the therapeutic efficacy of systemic anti-inflammatory therapy in this disease, we examined the impact of a nonsteroidal anti-inflammatory drug (NSAID), ketoprofen, and of a soluble TNF-α receptor (sTNF-R1) upon tumor necrosis factor (TNF)-α activity in a mouse model of acquired lymphedema.

Methods and Findings

Lymphedema was induced by microsurgical ablation of major lymphatic conduits in the murine tail. Untreated control mice with lymphedema developed significant edema and extensive histopathological inflammation compared to sham surgical controls. Short-term ketoprofen treatment reduced tail edema and normalized the histopathology while paradoxically increasing TNF-α gene expression and cytokine levels. Conversely, sTNF-R1 treatment increased tail volume, exacerbated the histopathology, and decreased TNF-α gene expression. Expression of vascular endothelial growth factor-C (VEGF-C), which stimulates lymphangiogenesis, closely correlated with TNF-α expression.

Conclusions

Ketoprofen therapy reduces experimental post-surgical lymphedema, yet direct TNF-α inhibition does not. Reducing inflammation while preserving TNF-α activity appears to optimize the repair response. It is possible that the observed favorable responses, at least in part, are mediated through enhanced VEGF-C signaling.

Physical activity for the affected limb and arm lymphedema after breast cancer surgery. A prospective, randomized controlled trial with two years follow-up

BACKGROUND. The influence of physical activity on the development of arm lymphedema (ALE) after breast cancer surgery with axillary node dissection has been debated. We evaluated the development of ALE in two different rehabilitation programs: a no activity restrictions (NAR) in daily living combined with a moderate resistance exercise program and an activity restrictions (AR) program combined with a usual care program. The risk factors associated with the development of ALE 2 years after surgery were also evaluated. MATERIAL AND METHODS. Women (n = 204) with a mean age of 55+/-10 years who had axillary node dissection were randomized into two different rehabilitation programs that lasted for 6 months: NAR (n = 104) or AR (n = 100). The primary outcomes were the difference in arm volume between the affected and control arms (Voldiff, in ml) and the development of ALE. Baseline (before surgery) and follow-up tests were performed 3 months, 6 months, and 2 years after surgery. Data were analyzed using ANCOVA and regression analysis. RESULTS. Voldiff did not differ significantly between the two treatment groups. Arm volume increased significantly over time in both the affected and the control arms. The development of ALE from baseline to 2 years increased significantly in both groups (p < 0.001). The only risk factor for ALE was BMI > 25 kg/m(2). CONCLUSION. Patients that undergo breast cancer surgery with axillary lymph node dissection should be encouraged to maintain physical activity in their daily lives without restrictions and without fear of developing ALE.

The unique biology of lymphatic edema

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.

G protein-coupled receptors as potential drug targets for lymphangiogenesis and lymphatic vascular diseases

G protein-coupled receptors (GPCRs) are widely expressed cell surface receptors that have been successfully exploited for the treatment of a variety of human diseases. Recent studies in genetically engineered mouse models have led to the identification of several GPCRs important for lymphatic vascular development and function. The adrenomedullin receptor, which consists of an oligomer between calcitonin receptor-like receptor and receptor activity modifying protein 2, is required for normal lymphatic vascular development and regulates lymphatic capillary permeability in mice. Numerous studies also suggest that lysophospholipid receptors are involved in the development of lymphatic vessels and lymphatic endothelial cell permeability. Given our current lack of pharmacological targets for the treatment of lymphatic vascular diseases like lymphedema, the continued identification and study of GPCRs in lymphatic endothelial cells may eventually lead to major breakthroughs and new pharmacological strategies for the treatment of lymphedema.