Diagnosis and management of lymphatic vascular disease

TRPV4-Expressing Tissue-Resident Macrophages Regulate the Function of Collecting Lymphatic Vessels via Thromboxane A2 Receptors in Lymphatic Muscle Cells

Rationale

TRPV4 channels are critical regulators of blood vascular function and have been shown to be dysregulated in many disease conditions in association with inflammation and tissue fibrosis. These are key features in the pathophysiology of lymphatic system diseases, including lymphedema and lipedema; however, the role of TRPV4 channels in the lymphatic system remains largely unexplored. TRPV4 channels are calcium permeable, non-selective cation channels that are activated by diverse stimuli, including shear stress, stretch, temperature, and cell metabolites, which may regulate lymphatic contractile function.

Objective

To characterize the expression of TRPV4 channels in collecting lymphatic vessels and to determine the extent to which these channels regulate the contractile function of lymphatics.

Methods and Results

Pressure myography on intact, isolated, and cannulated lymphatic vessels showed that pharmacological activation of TRPV4 channels with GSK1016790A (GSK101) led to contractile dysregulation. The response to GSK101 was multiphasic and included, 1) initial robust constriction that was sustained for ≥1 minute and in some instances remained for ≥4 minutes; and 2) subsequent vasodilation and partial or complete inhibition of lymphatic contractions associated with release of nitric oxide. The functional response to activation of TRPV4 channels displayed differences across lymphatics from four anatomical regions, but these differences were consistent across different species (mouse, rat, and non-human primate). Importantly, similar responses were observed following activation of TRPV4 channels in arterioles. The initial and sustained constriction was prevented with the COX inhibitor, indomethacin. We generated a controlled and spatially defined single-cell RNA sequencing (scRNAseq) dataset from intact and microdissected collecting lymphatic vessels. Our data uncovered a subset of macrophages displaying the highest expression of Trpv4 compared to other cell types within and surrounding the lymphatic vessel wall. These macrophages displayed a transcriptomic profile consistent with that of tissue-resident macrophages (TRMs), including differential expression of Lyve1 , Cd163 , Folr2 , Mrc1 , Ccl8 , Apoe , Cd209f , Cd209d , and Cd209g ; and at least half of these macrophages also expressed Timd4. This subset of macrophages also highly expressed Txa2s , which encodes the thromboxane A2 (TXA2) synthase. Inhibition of TXA2 receptors (TXA2Rs) prevented TRPV4-mediated contractile dysregulation. TXA2R activation on LMCs caused an increase in mobilization of calcium from intracellular stores through Ip3 receptors which promoted store operated calcium entry and vasoconstriction.

Conclusions

Clinical studies have linked cancer-related lymphedema with an increased infiltration of macrophages. While these macrophages have known anti-inflammatory and pro-lymphangiogenic roles, as well as promote tissue repair, our results point to detrimental effects to the pumping capacity of collecting lymphatic vessels mediated by activation of TRPV4 channels in macrophages. Pharmacological targeting of TRPV4 channels in LYVE1-expressing macrophages or pharmacological targeting of TXA2Rs may offer novel therapeutic strategies to improve lymphatic pumping function and lymph transport in lymphedema.

A Multiresolution Approach with Method-Informed Statistical Analysis for Quantifying Lymphatic Pumping Dynamics

Despite significant strides in lymphatic system imaging, the timely diagnosis of lymphatic disorders remains elusive. One main cause for this is the absence of standardized, quantitative methods for real-time analysis of lymphatic contractility. Here, we address this unmet need by combining near-infrared lymphangiography imaging with an innovative analytical workflow. We combined data acquisition, signal processing, and statistical analysis to integrate traditional peak and-valley with advanced wavelet time-frequency analyses. Decision theory was used to evaluate the primary drivers of attributable variance in lymphangiography measurements to generate a strategy for optimizing the number of repeat measurements needed per subject to increase measurement reliability. This approach not only offers detailed insights into lymphatic pumping behaviors across species, sex and age, but also significantly boosts the reliability of these measurements by incorporating multiple regions of interest and evaluating the lymphatic system under various gravitational loads. By addressing the critical need for improved imaging and quantification methods, our study offers a new standard approach for the imaging and analysis of lymphatic function that can improve our understanding, diagnosis, and treatment of lymphatic diseases. The results highlight the importance of comprehensive data acquisition strategies to fully capture the dynamic behavior of the lymphatic system.

Lymphangiogenesis and Lymphatic Zippering in Skin Associated with the Progression of Lymphedema

Secondary lymphedema often develops after lymph node dissection or radiation therapy for cancer treatment, resulting in marked skin fibrosis and increased stiffness owing to insufficiency of the lymphatic system caused by abnormal structure and compromised function. However, little is known about the associated changes of the dermal lymphatic vessels. In this study, using the lower limb skin samples of patients with secondary lymphedema, classified as types 1-4 by lymphoscintigraphy, we first confirmed the presence of epidermal thickening and collagen accumulation in the dermis, closely associated with the progression of lymphedema. Three-dimensional characterization of lymphatic capillaries in skin revealed prominent lymphangiogenesis in types 1 and 2 lymphedema. In contrast, increased recruitment of smooth muscle cells accompanied by development of the basement membrane in lymphatic capillaries was observed in types 3 and 4 lymphedema. Remarkably, the junctions of dermal lymphatic capillaries were dramatically remodeled from a discontinuous button-like structure to a continuous zipper-like structure. This finding is consistent with previous findings in an infection-induced mouse model. Such junction tightening (zippering) could reduce fluid transport and cutaneous viral sequestration during the progression of lymphedema and might explain the aggravation of secondary lymphedema. These findings may be helpful in developing stage-dependent treatment of patients with lymphedema.

Response of lymphatic endothelial cells to combined spatial and temporal variations in fluid flow

One-way valves within lymphatic vessels are required for the efficient drainage of lymphatic fluids. Fluid flow is proposed to be a key cue in regulating both the formation and maintenance of lymphatic valves. However, to our knowledge, no previous study has systematically examined the response of LECs to the complex combination of spatially and temporally varying fluid flows that occur at lymphatic valves in vivo. We built an in vitro microfluidic device that reproduces key aspects of the flow environment found at lymphatic valves. Using this device, we found that a combination of spatially and temporally varying wall shear stresses (WSSs) led to upregulated transcription of PROX1 and FOXC2. In addition, we observed that combined spatial and temporal variations in WSS-modulated Ca2+ signaling and led to increased cellular levels of NFATc1. These observations suggest that the physical cues generated by the flow environment present within lymphatic valves may act to activate key regulatory pathways that contribute to valve maintenance.

Abnormal Lymphatic Sphingosine-1-Phosphate Signaling Aggravates Lymphatic Dysfunction and Tissue Inflammation

BACKGROUND

Lymphedema is a global health problem with no effective drug treatment. Enhanced T-cell immunity and abnormal lymphatic endothelial cell (LEC) signaling are promising therapeutic targets for this condition. Sphingosine-1-phosphate (S1P) mediates a key signaling pathway required for normal LEC function, and altered S1P signaling in LECs could lead to lymphatic disease and pathogenic T-cell activation. Characterizing this biology is relevant for developing much needed therapies.

METHODS

Human and mouse lymphedema was studied. Lymphedema was induced in mice by surgically ligating the tail lymphatics. Lymphedematous dermal tissue was assessed for S1P signaling. To verify the role of altered S1P signaling effects in lymphatic cells, LEC-specific S1pr1-deficient (S1pr1LECKO) mice were generated. Disease progression was quantified by tail-volumetric and -histopathologic measurements over time. LECs from mice and humans, with S1P signaling inhibition, were then cocultured with CD4 T cells, followed by an analysis of CD4 T-cell activation and pathway signaling. Last, animals were treated with a monoclonal antibody specific to P-selectin to assess its efficacy in reducing lymphedema and T-cell activation.

RESULTS

Human and experimental lymphedema tissues exhibited decreased LEC S1P signaling through S1P receptor 1 (S1PR1). LEC S1pr1 loss-of-function exacerbated lymphatic vascular insufficiency, tail swelling, and increased CD4 T-cell infiltration in mouse lymphedema. LECs, isolated from S1pr1LECKO mice and cocultured with CD4 T cells, resulted in augmented lymphocyte differentiation. Inhibiting S1PR1 signaling in human dermal LECs promoted T-helper type 1 and 2 (Th1 and Th2) cell differentiation through direct cell contact with lymphocytes. Human dermal LECs with dampened S1P signaling exhibited enhanced P-selectin, an important cell adhesion molecule expressed on activated vascular cells. In vitro, P-selectin blockade reduced the activation and differentiation of Th cells cocultured with shS1PR1-treated human dermal LECs. P-selectin-directed antibody treatment improved tail swelling and reduced Th1/Th2 immune responses in mouse lymphedema.

CONCLUSIONS

This study suggests that reduction of the LEC S1P signaling aggravates lymphedema by enhancing LEC adhesion and amplifying pathogenic CD4 T-cell responses. P-selectin inhibitors are suggested as a possible treatment for this pervasive condition.

Back to the Future II-A Comprehensive Update on the Rapidly Evolving Field of Lymphatic Imaging and Interventions

ABSTRACT

Lymphatic imaging and interventional therapies of disorders affecting the lymphatic vascular system have evolved rapidly in recent years. Although x-ray lymphangiography had been all but replaced by the advent of cross-sectional imaging and the scientific focus shifted to lymph node imaging (eg, for detection of metastatic disease), interest in lymph vessel imaging was rekindled by the introduction of lymphatic interventional treatments in the late 1990s. Although x-ray lymphangiography is still the mainstay imaging technique to guide interventional procedures, several other, often less invasive, techniques have been developed more recently to evaluate the lymphatic vascular system and associated pathologies. Especially the introduction of magnetic resonance, and even more recently computed tomography, lymphangiography with water-soluble iodinated contrast agent has furthered our understanding of complex pathophysiological backgrounds of lymphatic diseases. This has led to an improvement of treatment approaches, especially of nontraumatic disorders caused by lymphatic flow abnormalities including plastic bronchitis, protein-losing enteropathy, and nontraumatic chylolymphatic leakages. The therapeutic armamentarium has also constantly grown and diversified in recent years with the introduction of more complex catheter-based and interstitial embolization techniques, lymph vessel stenting, lymphovenous anastomoses, as well as (targeted) medical treatment options. The aim of this article is to review the relevant spectrum of lymphatic disorders with currently available radiological imaging and interventional techniques, as well as the application of these methods in specific, individual clinical situations.

Abnormal lymphatic S1P signaling aggravates lymphatic dysfunction and tissue inflammation

BACKGROUND

Lymphedema is a global health problem with no effective drug treatment. Enhanced T cell immunity and abnormal lymphatic endothelial cell (LEC) signaling are promising therapeutic targets for this condition. Sphingosine-1-phosphate (S1P) mediates a key signaling pathway required for normal LEC function, and altered S1P signaling in LECs could lead to lymphatic disease and pathogenic T cell activation. Characterizing this biology is relevant for developing much-needed therapies.

METHODS

Human and mouse lymphedema was studied. Lymphedema was induced in mice by surgically ligating the tail lymphatics. Lymphedematous dermal tissue was assessed for S1P signaling. To verify the role of altered S1P signaling effects in lymphatic cells, LEC-specific S1pr1 -deficient ( S1pr1 LECKO ) mice were generated. Disease progression was quantified by tail-volumetric and -histopathological measurements over time. LECs from mice and humans, with S1P signaling inhibition, were then co-cultured with CD4 T cells, followed by an analysis of CD4 T cell activation and pathway signaling. Finally, animals were treated with a monoclonal antibody specific to P-selectin to assess its efficacy in reducing lymphedema and T cell activation.

RESULTS

Human and experimental lymphedema tissues exhibited decreased LEC S1P signaling through S1PR1. LEC S1pr1 loss-of-function exacerbated lymphatic vascular insufficiency, tail swelling, and increased CD4 T cell infiltration in mouse lymphedema. LECs, isolated from S1pr1 LECKO mice and co-cultured with CD4 T cells, resulted in augmented lymphocyte differentiation. Inhibiting S1PR1 signaling in human dermal LECs (HDLECs) promoted T helper type 1 and 2 (Th1 and Th2) cell differentiation through direct cell contact with lymphocytes. HDLECs with dampened S1P signaling exhibited enhanced P-selectin, an important cell adhesion molecule expressed on activated vascular cells. In vitro , P-selectin blockade reduced the activation and differentiation of Th cells co-cultured with sh S1PR1 -treated HDLECs. P-selectin-directed antibody treatment improved tail swelling and reduced Th1/Th2 immune responses in mouse lymphedema.

CONCLUSION

This study suggests that reduction of the LEC S1P signaling aggravates lymphedema by enhancing LEC adhesion and amplifying pathogenic CD4 T cell responses. P-selectin inhibitors are suggested as a possible treatment for this pervasive condition.

Clinical Perspective

What is New?: Lymphatic-specific S1pr1 deletion exacerbates lymphatic vessel malfunction and Th1/Th2 immune responses during lymphedema pathogenesis. S1pr1 -deficient LECs directly induce Th1/Th2 cell differentiation and decrease anti-inflammatory Treg populations. Peripheral dermal LECs affect CD4 T cell immune responses through direct cell contact.LEC P-selectin, regulated by S1PR1 signaling, affects CD4 T cell activation and differentiation.P-selectin blockade improves lymphedema tail swelling and decreases Th1/Th2 population in the diseased skin.What Are the Clinical Implications?: S1P/S1PR1 signaling in LECs regulates inflammation in lymphedema tissue.S1PR1 expression levels on LECs may be a useful biomarker for assessing predisposition to lymphatic disease, such as at-risk women undergoing mastectomyP-selectin Inhibitors may be effective for certain forms of lymphedema.

Lentiviral overexpression of VEGFC in transplanted MSCs leads to resolution of swelling in a mouse tail lymphedema model

BACKGROUND

Dysfunction of the lymphatic system following injury, disease, or cancer treatment can lead to lymphedema, a debilitating condition with no cure. Despite the various physical therapy and surgical options available, most treatments are palliative and fail to address the underlying lymphatic vascular insufficiency driving lymphedema progression. Stem cell therapy provides a promising alternative in the treatment of various chronic diseases with a wide range of therapeutic effects that reduce inflammation, fibrosis, and oxidative stress, while promoting lymphatic vessel (LV) regeneration. Specifically, stem cell transplantation is suggested to promote LV restoration, rebuild lymphatic circulation, and thus potentially be utilized towards an effective lymphedema treatment. In addition to stem cells, studies have proposed the administration of vascular endothelial growth factor C (VEGFC) to promote lymphangiogenesis and decrease swelling in lymphedema.

AIMS

Here, we seek to combine the benefits of stem cell therapy, which provides a cellular therapeutic approach that can respond to the tissue environment, and VEGFC administration to restore lymphatic drainage.

MATERIALS & METHODS

Specifically, we engineered mesenchymal stem cells (MSCs) to overexpress VEGFC using a lentiviral vector (hVEGFC MSC) and investigated their therapeutic efficacy in improving LV function and tissue swelling using near infrared (NIR) imaging, and lymphatic regeneration in a single LV ligation mouse tail lymphedema model.

RESULTS

First, we showed that overexpression of VEGFC using lentiviral transduction led to an increase in VEGFC protein synthesis in vitro. Then, we demonstrated hVEGFC MSC administration post-injury significantly increased the lymphatic contraction frequency 14-, 21-, and 28-days post-surgery compared to the control animals (MSC administration) in vivo, while also reducing tail swelling 28-days post-surgery compared to controls.

CONCLUSION

Our results suggest a therapeutic potential of hVEGFC MSC in alleviating the lymphatic dysfunction observed during lymphedema progression after secondary injury and could provide a promising approach to enhancing autologous cell therapy for treating lymphedema.

Prevalence of lymphedema among Anderson-Fabry disease patients: A report from the Fabry registry

BACKGROUND

Anderson-Fabry disease (AFD) is a rare X-linked lysosomal storage disease due to a genetic variation in the α-galactosidase A (GLA) gene. As a result, the activity of the α-galactosidase A (AGAL-A) enzyme is reduced or absent, which causes sphingolipid deposition within different body parts. AFD typically manifests with cardiovascular, renal, cerebrovascular, and dermatologic involvement. Lymphedema is caused by sphingolipid deposition within lymphatics. Lymphedema can cause intolerable pain and limit daily activities. Very limited data exist on lymphedema in AFD patients.

METHODS

Using data from the Fabry Registry (NCT00196742) with 7671 patients included (44% males and 56% females), we analyzed the prevalence of lymphedema among AFD patients who were ever assessed for lymphedema and studied the age of first reported lymphedema. Additionally, we assessed whether patients received AFD-specific treatment at some point during their clinical course. The data was stratified by gender and phenotype.

RESULTS

Our study showed that lymphedema occurred in 16.5% of the Fabry Registry patients who were ever assessed for lymphedema (n = 5487). Male patients when compared to female patient have higher prevalence (21.7% vs 12.7%) and experienced lymphedema at a younger age (median age at first reported lymphedema of 43.7 vs 51.7 years). When compared to other phenotypes, classic phenotype has the highest prevalence of lymphedema with the earliest reported lymphedema. Among those who reported lymphedema, 84.5% received AFD-specific treatment during their clinical course.

CONCLUSIONS

Lymphedema is a common manifestation of AFD in both genders, with a tendency to present later in female patients. Recognition of lymphedema can offer an important opportunity for intervention and potential impact on associated morbidity. Additional future studies are needed to characterize the clinical implications of lymphedema in AFD patients and identify additional treatment options for this growing population.

Lymphatic endothelial cell RXRα is critical for 9-cis-retinoic acid-mediated lymphangiogenesis and prevention of secondary lymphedema

Secondary lymphedema is a debilitating disease characterized by abnormal soft tissue swelling and caused by lymphatic system dysfunction. Despite a high prevalence of secondary lymphedema after cancer treatments, current management is supportive and there are no approved therapeutic agents that can thwart disease progression. We have previously demonstrated that 9-cis-retinoic acid (9-cisRA) has the potential to be repurposed for lymphedema as it mitigates disease by promoting lymphangiogenesis at the site of lymphatic injury. Although the efficacy of 9-cisRA has been demonstrated in previous studies, the mechanism of action is not completely understood. In this study, we demonstrate that when RXRα is specifically deleted in lymphatic endothelial cells, 9-cisRA fails to induce lymphangiogenesis in vitro and prevent pathologic progression of postsurgical lymphedema in vivo. These findings demonstrate that downstream nuclear receptor RXRα plays a critical role in the therapeutic efficacy of 9-cisRA in postsurgical lymphedema.

Adherence to Compression Garment Wear and Associated Factors Among Patients with Breast Cancer-Related Lymphedema: A Pilot Study from a Turkish Tertiary Center

Background: Compression garments are the basis of the maintenance phase of the breast cancer-related lymphedema (BCRL) treatment. The aim of this study is to investigate the adherence to compression garment wear and the associated factors among patients with BCRL. Methods and Results: Patients who received standard therapy and training on compression garment wear from a single center were asked to fill out a 28-item questionnaire on compression garment wear. Adherence to compression garment wear and the associated factors were examined. These factors were compared between patients who were wearing and who were not wearing compression garments as recommended. The study was completed with 60 patients. Twenty-five percent of the patients used custom-made compression garment. The rate of patients wearing compression garments as per recommendation was 51.7% (n = 31). The most common reasons for not wearing/discontinuation included functional difficulties in daily life (33%) and discomfort (28.8%). Compared according to the factors with potential impact on wearing, the rate of garment wear as per recommendation was statistically significantly higher in patients who had modified radical mastectomy than in those who had breast-conserving surgery (p = 0.038). Conclusion: Although standard information was provided to the patients, the adherence to compression garments was nonoptimal. The economic status of the patients is one of the main factors affecting the choice of compression garments and thus their adherence. To improve the adherence to this method, which is the basis of maintenance treatment of lymphedema, training programs to reduce patient beliefs and anxiety that are tailored to individual needs can be useful. Clinical trial registration number: NCT04832386.

Prolymphangiogenic Effects of 9-cis Retinoic Acid Are Enhanced at Sites of Lymphatic Injury and Dependent on Treatment Duration in Experimental Postsurgical Lymphedema

Background: Patients undergoing surgical treatment for solid tumors are at risk for development of secondary lymphedema due to intraoperative lymphatic vessel injury. The damaged lymphatic vessels fail to adequately regenerate and lymphatic obstruction leads to fluid and protein accumulation in the interstitial space and chronic lymphedema develops as a result. There are currently no effective pharmacological agents that reduce the risk of developing lymphedema or treat pre-existing lymphedema, and management is largely palliative. The present study investigated the efficacy of various 9-cis retinoic acid (9-cis RA) dosing strategies in reducing postsurgical lymphedema by utilizing a well-established mouse tail lymphedema model. Methods and Results: Short-duration treatment with 9-cis RA did not demonstrate a significant reduction in postoperative tail volume, nor an improvement in lymphatic clearance. However, long-term treatment with 9-cis RA resulted in decreased overall tail volume, dermal thickness, and epidermal thickness, with an associated increase in functional lymphatic clearance and lymphatic vessel density, assessed by LYVE-1 immunostaining, compared with control. These effects were seen at the site of lymphatic injury, with no significant changes observed in uninjured sites such as ear skin and the diaphragm. Conclusions: Given the reported results indicating that 9-cis RA is a potent promoter of lymphangiogenesis and improved lymphatic clearance at sites of lymphatic injury, investigation of postoperative 9-cis RA administration to patients at high risk of developing lymphedema may demonstrate positive efficacy and reduced rates of postsurgical lymphedema.

Interventional Management of Acquired Lymphatic Disorders

The lymphatic system is a complex network of tissues, vessels, and channels found throughout the body that assists in fluid balance and immunologic function. When the lymphatic system is disrupted related to idiopathic, iatrogenic, or traumatic disorders, lymphatic leaks can result in substantial morbidity and/or mortality. The diagnosis and management of these leaks is challenging. Modern advances in lymphatic imaging and interventional techniques have made radiology critical in the multidisciplinary management of these disorders. The authors provide a review of conventional and clinically relevant variant lymphatic anatomy and recent advances in diagnostic techniques such as MR lymphangiography. A detailed summary of technical factors related to percutaneous lymphangiography and lymphatic intervention is presented, including transpedal and transnodal lymphangiography. Traditional transabdominal access and retrograde access to the central lymph nodes and thoracic duct embolization techniques are outlined. Newer techniques including transhepatic lymphangiography and thoracic duct stent placement are also detailed. For both diagnostic and interventional radiologists, an understanding of lymphatic anatomy and modern diagnostic and interventional techniques is vital to the appropriate treatment of patients with acquired lymphatic disorders. ^©RSNA, 2022.

Recurrent Cellulitis: Who is at Risk and How Effective is Antibiotic Prophylaxis?

Recurrent cellulitis following successful treatment is common and prevention should be a major component in the management of cellulitis. Conditions that increase the risk of recurrence include chronic edema, venous disease, dermatomycosis and obesity. These risk factors should be actively managed as further episodes of cellulitis increases the risk of recurrence. The role of non-antibiotic measures is important and should be first-line in prevention. Antibiotic prophylaxis is effective, but its role is limited to non-purulent cellulitis where risk factors are appropriately managed.

Piper retrofractum extract and its component piperine promote lymphangiogenesis via an AKT- and ERK-dependent mechanism

Administration of Piper retrofractum extract (PRE) has been reported to alleviate edema, but the mechanism underlying this effect is unknown. Promotion of lymphangiogenesis is known to improve lymphedema, but the effect of PRE on lymphangiogenesis remains unclear. In the present study, we investigated whether PRE and specifically, piperine, the main component of PRE, can induce lymphangiogenesis. Treatments with PRE and piperine significantly promoted the proliferation, migration, and tube formation in human dermal lymphatic microvascular endothelial cells (HDLECs) but had no effect on the expression of lymphangiogenic factors. Furthermore, PRE and piperine significantly promoted the phosphorylation of the AKT and ERK proteins in HDLECs, and pretreatment with AKT and ERK inhibitors significantly attenuated the PRE- and piperine-induced lymphangiogenesis. These results indicate that PRE and piperine promote lymphangiogenesis via an AKT- and ERK-dependent mechanism. PRACTICAL APPLICATIONS: The lymphatic system plays various roles such as maintaining tissue fluid homeostasis, immune defense, and metabolism. Disruption of the lymphatic system results in insufficient fluid drainage, which causes edema. Currently, there are no effective treatments for lymphedema; therefore, the development of novel treatment strategies is desirable. In this study, we showed that PRE and its main component piperine promote lymphangiogenesis in lymphatic endothelial cells. Therefore, PRE has the potential to be used as a novel functional food for relieving lymphedema.

Hypoxia and Hypoxia-Inducible Factors in Lymphedema

Lymphedema is a chronic inflammatory disorder characterized by edema, fat deposition, and fibrotic tissue remodeling. Despite significant advances in lymphatic biology research, our knowledge of lymphedema pathology is incomplete. Currently, there is no approved pharmacological therapy for this debilitating disease. Hypoxia is a recognized feature of inflammation, obesity, and fibrosis. Understanding hypoxia-regulated pathways in lymphedema may provide new insights into the pathobiology of this chronic disorder and help develop new medicinal treatments.

Can YouTube be used as an educational tool in lymphedema rehabilitation?

Background

Lymphedema is defined as the abnormal accumulation of interstitial fluid and fibro-adipose tissues resulting from injury, infection, or congenital abnormalities of the lymphatic system. The gold standard approach in the treatment of lymphedema is Complete Decongestive Therapy and it has many components that require practical knowledge and skills. YouTube can be a useful tool to provide these skills to healthcare professionals and patients. The aim of this study was to examine the videos about lymphedema rehabilitation on YouTube and analyze their technical features, sources, contents, educational value and reliability.

Methods

The YouTube database was searched using the “lymphedema rehabilitation”, “lymphedema treatment”, “complete decongestive therapy”, “lymphedema massage”, and “lymphedema exercises” keywords. Two reviewers (Physical medicine and rehabilitation specialist) assessed videos for educational quality using a Global Quality Scale (GQS). To evaluate the reliability the 5-point Discern scale was used.

Results

A total of 90 videos, which met the inclusion criteria were included in the analysis. The mean duration of the videos was 8.9 ± 10.5 min. The mean number of daily views was 22.7 ± 47.1 for a day. The majority of the videos were created to inform patients (57.8%).The uploaders were mostly private healthcare institutions or healthcare professionals (65.6%). Information providers were lymphedema therapists mostly (63.3%). Manual lymphatic drainage was observed to stand out as the most mentioned lymphedema rehabilitation component on YouTube. The mean of reliability and GQS scores of the videos were 2.2 ± 1.0 and 2.7 ± 1.0, respectively.

Conclusions

The biggest obstacle for YouTube to be an excellent source of information is that it hosts large volumes of uncontrolled and low-quality data. When Youtube content related to lymphedema rehabilitation was examined, it was observed that many videos were quite insufficient and incomplete even though there were useful videos. If careful controlling measures are implemented and if medical videos aim to meet reliability and GQS criteria, YouTube can become an effective and useful source of information for lymphedema rehabilitation.

Animal Models Used in the Research of Vascularized Lymph Node Transfer: A Systematic Review

BACKGROUND

Lymphedema is a common adverse consequence of breast cancer therapy, while still relatively little is known about its pathophysiology. Several treatment options emerged over the past decades, and among them, vascularized lymph node transfer (VLNT) seems to be particularly promising. Animal models are indispensable to improve our understanding of the underlying processes surrounding the transplantation of a vascularized lymph node. This review aimed to systematically evaluate animal models of VLNT and compare their advantages and disadvantages.

MATERIALS AND METHODS

A systematic review of literature in the Scopus, Web of Science, and Ovid MEDLINE databases was conducted according to the PRISMA guidelines to identify all studies on animal models used for the research of VLNT. The algorithm used in search of articles was "Vascularized Lymph Node Transfer" AND "Model". Articles were manually verified for relevance to the topic. The resulting models were assessed for their suitability for VLNT research.

RESULTS

The literature search yielded a total of 233 studies after duplicates removal. Of those, 217 were excluded based on title and abstract review. Another study was excluded after reviewing the full-text article leaving 15 eligible studies to be included in this review article.

CONCLUSIONS

Rats were found to be the most dominantly used animal model in the VLNT research, although other models had their benefits. The main areas of study were the functionality of VLNT within or without a preinduced lymphedema, its response to ischemia, and clarification of lymphatic pathways reestablishment following VLNT.

A case report of RASA1-associated inherited lymphoedema with recurrent life-threatening lymphangitis

Background

Most cases of lymphoedema are secondary to other causes, while cases of primary lymphoedema, in particular that of congenital origin, are uncommon. Limited genetic disorders are so far known to be associated with lymphatic malformation including mutations in RASA1. This clinical case highlights the possible complications of RASA1-associated lymphatic malformation in a female suffering from recurrent life-threatening septic lymphangitis.

Case summary

A 23-year-old female patient presented with congenital lymphoedema of the lower right extremity. At the age of eight, she first suffered from an episode of lymphangitis. Thereafter, she developed recurrent episodes of lymphangitis predominately occurring during menstruation and culminating into severe and life-threatening septicaemias. Due to the menstrual association, endometriosis was suspected but could not be confirmed. Furthermore, angiography could not detect any sign of arteriovenous fistula. Single-Photon-Emission-Computed-Tomography confirmed absent major lymphatics of the right leg with severely impaired and prolonged dermal lymphatic backflow. Genetic testing identified a disease-causing variant in the RASA1 gene.

Discussion

To our knowledge, this is the first case of recurrent septic lymphangitis with close relation to menstruation in a female with RASA1-associated lymphatic malformation. Due to the possible de novo or somatic origin of a pathogenic variant, a genetic disease should be considered in spite of an unremarkable family history or a localized lymphoedema. Although there is no curative therapy available yet, the knowledge of the underlying genetic defect is important for interdisciplinary patient care and might be crucial for individual molecular therapies in the future.

Biology of Lymphedema

Simple Summary

Lymphedema is a chronic, debilitating disease of the lymphatic vasculature. Although several reviews focus on the anatomy and physiology of the lymphatic system, this review provides an overview of the lymphatic vasculature and, moreover, of lymphatic system dysfunction and lymphedema. Further, we aim at advancing the knowledge in the area of lymphatic system function and how dysfunction of the lymphatic system—as seen in lymphedema—affects physiological systems, such as the cardiovascular system, and how those might be modulated by lymphedema therapy.

Abstract

This narrative review portrays the lymphatic system, a poorly understood but important physiological system. While several reviews have been published that are related to the biology of the lymphatic system and lymphedema, the physiological alternations, which arise due to disturbances of this system, and during lymphedema therapy, are poorly understood and, consequently, not widely reported. We present an inclusive collection of evidence from the scientific literature reflecting important developments in lymphedema research over the last few decades. This review aims at advancing the knowledge on the area of lymphatic system function as well as how system dysfunction, as seen in lymphedema, affects physiological systems and how lymphedema therapy modulates these mechanisms. We propose that future studies should aim at investigating, in-detail, aspects that are related to fluid regulation, hemodynamic responses, and endothelial and/or vascular changes due to lymphedema and lymphedema therapy.

Effects of physical therapy on hyaluronan clearance and volume regulating hormones in lower limb lymphedema patients: A pilot study

Lymphedema is manifested as a chronic swelling arising due to stasis in the lymphatic flow. No cure is currently available. A non-invasive treatment is a 3 week complete decongestive therapy (CDT), including manual lymphatic drainage and compression bandaging to control swelling. As CDT leads to mobilization of several liters of fluid, effects of CDT on hyaluronan clearance (maker for lymphatic outflow), volume regulating hormones, total plasma protein as well as plasma density, osmolality and selected electrolytes were investigated. In this pilot study, we assessed hyaluronan and volume regulating hormone responses from plasma samples of nine patients (three males, six females, aged 55 ± 13 years) with lower limb lymphedema stage II-III, before - and after - CDT. A paired non-parametric test (Wilcoxon) was used to assess hormonal and plasma volume changes. Correlation was tested using Spearman's correlation. The main findings of this novel study are that lymphedema patients lost volume and weight after therapy. Hyaluronic acid did not significantly change pre- compared to post-CDT. Aldosterone increased significantly after therapy, while plasma renin activity increased, but not significantly. Plasma total protein, density, osmolality and sodium and chloride did not show differences after CDT. To our knowledge, no study has previously investigated the effects of CDT on volume regulating hormones or electrolytes. To identify the time-course of volume regulating hormones and lymphatic flow changes induced by CDT, future studies should assess these parameters serially over 3 weeks of therapy.

Correlation of disease comorbidity with prescribed treatment among insured U.S. lymphedema patients

OBJECTIVE

The objective of this study was to define the current forms of treatment in a contemporary population of lymphedema (LED) patients for LED related to breast cancer, the most prevalently diagnosed LED comorbidity in Western countries, and phlebolymphedema with venous leg ulcer (PLEDU), a sequela of chronic venous disease. The goals of LED therapy are to reduce edema, thereby improving function and related symptoms, and to improve skin integrity to prevent development of infection. Treatment is generally nonsurgical: conservative care, including complex physical therapy, manual lymphatic drainage, and compression bandaging; or pneumatic compression device (PCD) therapy by a simple nonprogrammable device or an advanced programmable device.

METHODS

To determine the frequency of individual types of treatment for LED and their relationship to breast cancer-related lymphedema (BCRL) and PLEDU, we queried claims from a deidentified Health Insurance Portability and Accountability Act-compliant commercial administrative insurance database with >165 million members. A total of 26,902 patients identified with LED who had been enrolled with continuous medical benefits for 12 months before and after the index date for the complete years 2012 through 2016 were separated into four treatment categories: no treatment, conservative care, simple PCD (SPCD), and advanced PCD. LED treatment was related to the BCRL and PLEDU comorbidities.

RESULTS

BCRL patients, who represented 32.1% of all study patients, made up 41% of all patients receiving conservative care and 24% of patients receiving PCD therapy. By contrast, PLEDU patients (9.6% of study patients) were proportionally under-represented in the conservative care group (7.8%) but composed a disproportionately high share of the PCD therapy group (17.7%). PLEDU patients represented 23.5% of all LED patients prescribed SPCD therapy, whereas BCRL patients composed 10.3% of total LED patient SPCD prescriptions (P < .001).

CONCLUSIONS

Our analysis of a large health care administrative database showed clear differences between the way BCRL and PLEDU patients are treated. Compared with BCRL patients, PLEDU patients were less likely to receive conservative care and more likely to be prescribed SPCDs for pneumatic compression therapy. These differences suggest that lymphatic therapy may be undervalued for treatment of chronic venous swelling and prevention and treatment of PLEDU.

Perpendicular alignment of lymphatic endothelial cells in response to spatial gradients in wall shear stress

One-way valves in the lymphatic system form from lymphatic endothelial cells (LECs) during embryonic development and are required for efficient tissue drainage. Although fluid flow is thought to guide both valve formation and maintenance, how this occurs at a mechanistic level remains incompletely understood. We built microfluidic devices that reproduce critical aspects of the fluid flow patterns found at sites of valvulogenesis. Using these devices, we observed that LECs replicated aspects of the early steps in valvulogenesis: cells oriented perpendicular to flow in the region of maximum wall shear stress (WSS) and exhibited enhanced nuclear localization of FOXC2, a transcription factor required for valvulogenesis. Further experiments revealed that the cell surface protein E-selectin was required for both of these responses. Our observations suggest that spatial gradients in WSS help to demarcate the locations of valve formation, and implicate E-selectin as a component of a mechanosensory process for detecting WSS gradients.

Using microfluidic systems, Michalaki et al show that lymphatic endothelial cells exposed to wall shear stress orient in the direction perpendicular to flow and show increased nuclear FOXC2 levels in a manner dependent on E-selectin, a transmembrane adhesion protein. These data provide insights into how lymphatic vessels respond to local flow-mediated mechanical cues.

Effects of mobilized peripheral blood stem cells on treatment of primary lower extremity lymphedema

OBJECTIVE

Lymphedema is a chronic debilitating disease characterized by the accumulation of fluid in the extremities as a result of lymphatic system impairment. Current treatments fail to restore the functionality and structural integrity of the lymphatic vessels lost in this condition. In this study, autologous mobilized peripheral blood stem cell transplantation was used and its potential efficacy and safety were evaluated in treating this condition.

METHODS

Ten patients with primary lymphedema in the lower extremity received granulocyte-colony stimulating factor subcutaneously for 4 days, to stimulate stem cell mobilization, after which 200 to 250 mL of blood was drawn from each patient and used to collect stem cells. Mobilized stem cells were counted by flow cytometry with International Society of Hematotherapy and Graft Engineering method. In two sessions, 3 weeks apart, these stem cells were injected subcutaneously in the affected limb at approximately 80 points, along the lymphatic vessels. Each patient was followed for 6 months, during which changes in the limb volume and circumference were measured. Lymphangiogenesis was evaluated by biopsy, the lymphoscintigraphic transport index was calculated using Lymphoscintigraphy, and quality of life was surveyed.

RESULTS

In this study, patients received on average 9.5 ± 6.8 × 10⁸ mononuclear cells (which divided into 2 × 10⁶ CD34⁺ cells for each session) in two sessions. The volume of the lower limbs decreased in 60% of patients. One patient showed a slight increase in the volume of lower limbs and three showed no change. The average limb volume was 4469.41 ± 1760.71 cm³, which on average differed from the average initial limb volume by 232.88 ± 392.53 cm³. Quality of life was reported as slightly increased in 60% of patients. The lymphoscintigraphic transport index suggested improvement in 60% of the patients. Likewise, tissue samples showed a 60% increase in lymphatic vessels.

CONCLUSIONS

Subcutaneous injection of autologous hematopoietic stem cells harvested from peripheral blood into patients with primary lower limb lymphedema is feasible, potentially effective, and without serious adverse effects. However, a larger scale study with more patients is needed to validate our results. Last, to increase the effectiveness of this treatment, the optimal dose of cells injected and the requirement for additional growth factors need further study.

A Pre-clinical Animal Model of Secondary Head and Neck Lymphedema

Head and neck lymphedema (HNL) is a disfiguring disease affecting over 90% of patients treated for head and neck cancer. Animal models of lymphedema are used to test pharmacologic and microsurgical therapies; however, no animal model for HNL is described in the literature to date. In this study we describe the first reproducible rat model for HNL. Animals were subjected to two surgical protocols: (1) lymphadenectomy plus irradiation; and (2) sham surgery and no irradiation. Head and neck expansion was measured on post-operative days 15, 30 and 60. Magnetic resonance imaging (MRI) was acquired at the same time points. Lymphatic drainage was measured at day 60 via indocyanine green (ICG) lymphography, after which animals were sacrificed for histological analysis. Postsurgical lymphedema was observed 100% of the time. Compared to sham-operated animals, lymphadenectomy animals experienced significantly more head and neck swelling at all timepoints (P < 0.01). Lymphadenectomy animals had significantly slower lymphatic drainage for 6 days post-ICG injection (P < 0.05). Histological analysis of lymphadenectomy animals revealed 83% greater subcutis thickness (P = 0.008), 22% greater collagen deposition (P = 0.001), 110% greater TGFβ1+ cell density (P = 0.04), 1.7-fold increase in TGFβ1 mRNA expression (P = 0.03), and 114% greater T-cell infiltration (P = 0.005) compared to sham-operated animals. In conclusion, animals subjected to complete lymph node dissection and irradiation developed changes consistent with human clinical postsurgical HNL. This was evidenced by significant increase in all head and neck measurements, slower lymphatic drainage, subcutaneous tissue expansion, increased fibrosis, and increased inflammation compared to sham-operated animals.

Does tumescent liposuction damage the lymph vessels in lipoedema patients?

Background

Lymphatic insufficiency might play a significant role in the pathophysiology of lipoedema. Liposuction is up to now the best treatment. As liposuction is invasive, the technique could destruct parts of the lymphatic system and by this aggravate the lymphatic component and/or induce lymphoedema. We investigated the function of the lymphatic system in lipoedema patients before and after tumescent liposuction and thus whether tumescent liposuction can be regarded as a safe treatment.

Methods

Lymphoscintigraphy was performed to quantify the lymph outflow of 117 lipoedema patients. Mean clearance percentages of radioactive protein loaded after 1 min with respect to the total injected dose and corrected for decay of the radiopharmaceutical in the subcutaneous lymphatics were used as functional quantitative parameters as well as the clearance percentages and inguinal uptake 2 h post injection. The results of lymphatic function in lipoedema patients were compared with values obtained from normal healthy volunteers. We also compared 50 lymphoscintigraphies out of the previous 117 lipoedema patients before and six months after tumescent liposuction.

Results

In 117 lipoedema patients clearance 2 h post injection in the right and left foot was disturbed in 79.5 and 87.2% respectively. The inguinal uptake 2 h post injection in the right and left groin was disturbed in 60.3 and 64.7% respectively. In 50 lipoedema patients mean clearance and inguinal uptake after tumescent liposuction were slightly improved, 0.01 (p = 0.37) versus 0.02 (p = 0.02), respectively. This is statistically not relevant in clearance.

Conclusion

Lipoedema legs have a delayed lymph transport. Tumescent liposuction does not diminish the lymphatic function in lipoedema patients, thus tumescent liposuction can be regarded as a safe treatment.

Cancer-associated secondary lymphoedema

Lymphoedema is an oedematous condition with a specific and complex tissue biology. In the clinical context of cancer, the pathogenesis of lymphoedema ensues most typically from the modalities employed to stage and treat the cancer (in particular, surgery and radiotherapy). Despite advances in cancer treatment, lifelong lymphoedema (limb swelling and the accompanying chronic inflammatory processes) affects approximately one in seven individuals treated for cancer, although estimates of lymphoedema prevalence following cancer treatment vary widely depending upon the diagnostic criteria used and the duration of follow-up. The natural history of cancer-associated lymphoedema is defined by increasing limb girth, fibrosis, inflammation, abnormal fat deposition and eventual marked cutaneous pathology, which also increases the risk of recurrent skin infections. Lymphoedema can substantially affect the daily quality of life of patients, as, in addition to aesthetic concerns, it can cause discomfort and affect the ability to carry out daily tasks. Clinical diagnosis is dependent on comparison of the affected region with the equivalent region on the unaffected side and, if available, with pre-surgical measurements. Surveillance is indicated in this high-risk population to facilitate disease detection at the early stages, when therapeutic interventions are most effective. Treatment modalities include conservative physical strategies that feature complex decongestive therapy (including compression garments) and intermittent pneumatic compression, as well as an emerging spectrum of surgical interventions, including liposuction for late-stage disease. The future application of pharmacological and microsurgical therapeutics for cancer-associated lymphoedema holds great promise.

Assessment of Mechanical Properties of Tissue in Breast Cancer-Related Lymphedema Using Ultrasound Elastography

Breast cancer-related lymphedema is a consequence of a malfunctioning lymphatic drainage system resulting from surgery or some other form of treatment. In the initial stages, minor and reversible increases in the fluid volume of the arm are evident. As the stages progress over time, the underlying pathophysiology dramatically changes with an irreversible increase in arm volume most likely due to a chronic local inflammation leading to adipose tissue hypertrophy and fibrosis. Clinicians have subjective ways to stage the degree and severity such as the pitting test which entails manually comparing the elasticity of the affected and unaffected arms. Several imaging modalities can be used but ultrasound appears to be the most preferred because it is affordable, safe, and portable. Unfortunately, ultrasonography is not typically used for staging lymphedema, because the appearance of the affected and unaffected arms is similar in B-mode ultrasound images. However, novel ultrasound techniques have emerged, such as elastography, which may be able to identify changes in mechanical properties of the tissue related to detection and staging of lymphedema. This paper presents a novel technique to compare the mechanical properties of the affected and unaffected arms using quasi-static ultrasound elastography to provide an objective alternative to the current subjective assessment. Elastography is based on time delay estimation (TDE) from ultrasound images to infer displacement and mechanical properties of the tissue. We further introduce a novel method for TDE by incorporating higher order derivatives of the ultrasound data into a cost function and propose a novel optimization approach to efficiently minimize the cost function. This method works reliably with our challenging patient data. We collected radio frequency ultrasound data from both arms of seven patients with stage 2 lymphedema, at six different locations in each arm. The ratio of strain in skin, subcutaneous fat, and skeletal muscle divided by strain in the standoff gel pad was calculated in the unaffected and affected arms. The p -values using a Wilcoxon sign-rank test for the skin, subcutaneous fat, and skeletal muscle were 1.24×10^-5 , 1.77×10^-8 , and 8.11×10^-7 respectively, showing differences between the unaffected and affected arms with a very high level of significance.

Surgical interventions for the prevention or treatment of lymphoedema after breast cancer treatment

BACKGROUND

Breast cancer is the most common type of cancer amongst women worldwide, and one distressing complication of breast cancer treatment is breast and upper-limb lymphoedema. There is uncertainty regarding the effectiveness of surgical interventions in both the prevention and management of lymphoedema affecting the arm after breast cancer treatment.

OBJECTIVES

1. To assess and compare the efficacy of surgical interventions for the prevention of the development of lymphoedema (LE) in the arm after breast cancer treatment.2. To assess and compare the efficacy of surgical interventions for the treatment of established LE in the arm after breast cancer treatment.

SEARCH METHODS

We searched the Cochrane Breast Cancer Group's Specialised Register, the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), the WHO International Clinical Trials Registry Platform (ICTRP) and ClinicalTrials.gov for all prospectively registered and ongoing trials on 2 November 2017. Reference lists of included studies were also handsearched by three review authors for additional eligible trials.

SELECTION CRITERIA

All randomised controlled trials (RCTs) comparing a surgical intervention for the prevention or treatment of lymphoedema of the arm after breast cancer treatment to either standard intervention, placebo intervention, or another surgical intervention were included. Patients of both sexes and all ages who have had treatment for their breast cancer were considered. No limits were applied to language or study location. Three authors independently determined the eligibility of each study.

DATA COLLECTION AND ANALYSIS

Three authors independently extracted data for each included study using a pre-designed data extraction pro forma and used Cochrane's 'risk of bias' tool for assessing risk of bias. Dichotomous variables were analysed using the Mantel-Haenszel method to estimate risk ratios (RRs). Differences in continuous variables were expressed as mean differences (MDs). GRADE was used to assess the certainty of the evidence provided by the included studies.

MAIN RESULTS

Two studies involving 95 participants examined surgical interventions for preventing breast cancer-related lymphoedema. Both studies evaluated the efficacy of the lymphaticovenular anastomosis technique as part of a preventative management protocol. Both studies were deemed to be at unclear risk of bias overall. Statistical variation between the studies was low, which increases the reliability of the evidence. However, the two studies were conducted in the same centre. Lymphaticovenular anastomosis appears to result in a reduction in the incidence of lymphoedema compared to nonoperative management with a risk ratio of 0.20 (95% CI 0.06 to 0.63, P = 0.006; 95 participants; low-certainty evidence). The RCTs did not evaluate any of the secondary outcomes.One study involving 36 participants evaluated the effectiveness of vascularised lymph node transfer for treating breast cancer-related lymphoedema. The trial was deemed to be at unclear risk of bias. For participants suffering from stage 2 lymphoedema, the evidence suggested reductions in limb volume (MD -39.00%, 95% CI -47.37% to -30.63%, very low-certainty evidence), pain scores (MD -4.16, 95% CI -5.17 to -3.15, very low-certainty evidence), heaviness sensation (MD -4.27, 95% CI -5.74 to -2.80, very low-certainty evidence), mean number of infections/year (MD -1.22, 95% CI -2.00 to -0.44, very low-certainty evidence), and an improvement in overall function scores (MD -3.77, 95% CI -4.89 to -2.65, very low-certainty evidence) for those who had undergone vascularised lymph node transfer compared to those who had undergone no treatment.

AUTHORS' CONCLUSIONS

There is low-certainty evidence that lymphaticovenular anastomosis is effective in preventing the development of lymphoedema after breast cancer treatment based on the findings from two studies. One study providing very low-certainty evidence found that vascularised lymph node transfer is an efficacious option in the treatment of established stage 2 lymphoedema related to breast cancer. Important secondary outcomes in this review were rarely reported in the included studies. More high-quality RCTs are required to further elucidate the effectiveness of surgical interventions in the prevention and treatment of lymphoedema after breast cancer treatment. At the time of this review, no ongoing trials on this topic were identified.

Quality of life in adults with lymphedema cholestasis syndrome 1

BACKGROUND

LCS1 (Lymphedema Cholestasis Syndrome 1/Aagenaes syndrome) is a rare, hereditary disorder, where the highest known prevalence is in Norway. The disorder is characterized by lymphedema and periodic cholestasis from birth or the neonatal period. This study aimed to examine internal reliability of the SF-36, in addition to the group's overall- and health related quality of life (OQoL and HRQoL) and psychosocial well-being.

METHODS

Twenty adults (aged 18-65) in Norway have been diagnosed with LSC1. Eighteen of these patients were included in the study and completed four questionnaires on overall and health related quality of life and psychosocial well-being: Cantril's Ladder (CL), The Kaasa Test, the SF-36, and a lymphedema anamnesis questionnaire. Demographic data were registered, and 15 of the patients underwent a physical examination of the lymphedema. SF-36 scores were compared with those of 360 age and gender matched controls drawn from an earlier survey of the Norwegian general population. The Mann-Whitney U test and Chi-square (χ²) test were used to test internal differences in the patient group.

RESULTS

Health-related quality of life (HRQOL) was significantly reduced in patients with LSC1 compared to controls, in three out of eight areas, role physical, general health and mental health. Females scored significantly better than males in the patient group in two areas of SF-36, in CL, and in one of three scales of The Kaasa Test. Severe lymphedema was found to be significantly correlated to bodily pain and reduced mental health. The level of education was positively correlated to mental health.

CONCLUSION

Overall quality of life (OQoL), health related quality of life (HRQoL) and psycho-social well-being were good in the patient group, but some dimensions of HRQoL were reduced. More severe extent of lymphedema was associated with poorer HRQoL.

Mir-126 is a conserved modulator of lymphatic development

Organ homeostasis relies upon cellular and molecular processes that restore tissue structure and function in a timely fashion. Lymphatic vessels help maintain fluid equilibrium by returning interstitial fluid that evades venous uptake back to the circulation. Despite its important role in tissue homeostasis, cancer metastasis, and close developmental origins with the blood vasculature, the number of molecular players known to control lymphatic system development is relatively low. Here we show, using genetic approaches in zebrafish and mice, that the endothelial specific microRNA mir-126, previously implicated in vascular integrity, regulates lymphatic development. In zebrafish, in contrast to mir-126 morphants, double mutants (mir-126a^-/-; mir-126b^-/-, hereafter mir-126^-/-) do not exhibit defects in vascular integrity but develop lymphatic hypoplasia; mir-126^-/- animals fail to develop complete trunk and facial lymphatics, display severe edema and die as larvae. Notably, following MIR-126 inhibition, human Lymphatic Endothelial Cells (hLECs) respond poorly to VEGFA and VEGFC. In this context, we identify a concomitant reduction in Vascular Endothelial Growth Factor Receptor-2 (VEGFR2) and Vascular Endothelial Growth Factor Receptor-3 (VEGFR3, also known as FLT4) expression upon MIR-126 inhibition. In vivo, we further show that flt4^+/- zebrafish embryos exhibit lymphatic defects after mild miR-126 knockdown. Similarly, loss of Mir-126 in Flt4^+/- mice results in embryonic edema and lethality. Thus, our results indicate that miR-126 modulation of Vegfr signaling is essential for lymphatic system development in fish and mammals.

Leukotriene B4 antagonism ameliorates experimental lymphedema

Acquired lymphedema is a cancer sequela and a global health problem currently lacking pharmacologic therapy. We have previously demonstrated that ketoprofen, an anti-inflammatory agent with dual 5-lipoxygenase and cyclooxygenase inhibitory properties, effectively reverses histopathology in experimental lymphedema. We show that the therapeutic benefit of ketoprofen is specifically attributable to its inhibition of the 5-lipoxygenase metabolite leukotriene B₄ (LTB₄). LTB₄ antagonism reversed edema, improved lymphatic function, and restored lymphatic architecture in the murine tail model of lymphedema. In vitro, LTB₄ was functionally bimodal: Lower LTB₄ concentrations promoted human lymphatic endothelial cell sprouting and growth, but higher concentrations inhibited lymphangiogenesis and induced apoptosis. During lymphedema progression, lymphatic fluid LTB₄ concentrations rose from initial prolymphangiogenic concentrations into an antilymphangiogenic range. LTB₄ biosynthesis was similarly elevated in lymphedema patients. Low concentrations of LTB₄ stimulated, whereas high concentrations of LTB₄ inhibited, vascular endothelial growth factor receptor 3 and Notch pathways in cultured human lymphatic endothelial cells. Lymphatic-specific Notch1^-/- mice were refractory to the beneficial effects of LTB₄ antagonism, suggesting that LTB₄ suppression of Notch signaling is an important mechanism in disease maintenance. In summary, we found that LTB₄ was harmful to lymphatic repair at the concentrations observed in established disease. Our findings suggest that LTB₄ is a promising drug target for the treatment of acquired lymphedema.

Complex Decongestive Therapy Enhances Upper Limb Functions in Patients with Breast Cancer-Related Lymphedema

BACKGROUND

We aimed to evaluate the effects of complex decongestive therapy (CDT) on upper extremity functions, the severity of pain, and quality of life. We also searched the impact of the sociodemographic and clinical characteristics on the improvement in upper extremity functions.

METHODS

A total of 37 women with breast cancer-related lymphedema (BCRL) [age, 53.6 ± 11.2 (28-72)] were included in this study. All patients underwent CDT-phase 1 program, including meticulous skin care, manual lymphatic drainage, remedial exercises, and compression bandages. Arm volume was calculated by a formula for truncated cone using circumferential measurements. A baseline questionnaire, including sociodemographic and clinical properties, was used for each patient. Short Form-36 (SF-36), Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire, and Visual Analog Scale (VAS) for pain and heaviness were used as clinical assessment scales.

RESULTS

The mean of the posttreatment volume of the affected limb was lower compared to pretreatment volume (2741.81 ± 696.85 and 2990.67 ± 745.49, respectively), and the mean percentage change in edema volume was 38.1% ± 26.5%. We observed a statistically significant reduction in pain and heaviness VAS scores and improvement of shoulder mobility among upper extremities with lymphedema (p < 0.001) after CDT. The mean of posttreatment DASH score was lower compared to pretreatment score (37.19 ± 16.01, 49.81 ± 18.84, respectively, p < 0.001). All subgroups of the SF-36 parameters were increased after the CDT application (p < 0.01). Besides being under 65 years old, having a body mass index above 30 and short duration of lymphedema were found to be related to greater improvement in upper extremity functions.

CONCLUSIONS

CDT provides enhancement of upper extremity functions and quality of life in patients with BCRL. The reduction in lymphedema volume, pain, and heaviness and the improvement in shoulder mobility may be the contributed factors.

Efficacy of Complementary Therapies in the Quality of Life of Breast Cancer Survivors

Breast cancer (BC) is the most common cancer diagnosed in women and the second most common cancer overall, ranking as the fifth cause of death from cancer. The chronicity of the disease produces long-term physiological and psychological manifestations, which adversely affect the quality of life of the individual. The primary treatment while managing cancer presents with various debilitating side effects. With the recent advances in treatment techniques that have improved the survival rate, patients suffer from continuing posttreatment complications. Patients seem to cope well with the stress of treatment of BC and sustain a normal life; however, the deterioration in physical well-being makes the patient functionally inefficient. Exercise has been proven to be an effective, safe, and feasible tool in combating the adverse effects of treatment, prevents complications and decreases the risk of BC-specific mortality. This review briefly presents an overview of the burden of the disease and its management strategies. Owing to the heterogeneity of the population and the multitude of therapies they receive, the response of each patient to treatment is different and so is the magnitude of adverse effects. The review discusses the late sequelae following treatment and evidence supporting the role of physical activity in their management. In conclusion, there is a need for personalized physical activity plans to be developed to suit the individual and their circumstances.

Treatment of lipoedema using liposuction

Hintergrund: Beim Lipödem handelt es sich um eine schmerzhafte, anlagebedingt übermäßige Fettgewebsvermehrung der Extremitäten bei Frauen. Die Ursache ist unbekannt. Ebenso unbekannt ist die Zahl der betroffenen Frauen in Deutschland. Eine eigene Untersuchung zur Epidemiologie wird vorgestellt. Als Therapiemöglichkeit stehen die Komplexe Physikalische Entstauungstherapie und die Liposuktion zur Verfügung. Nur durch die Liposuktion ist eine dauerhafte Entfernung des Fettgewebes möglich. Ihre Wirksamkeit wird in einer weiteren Untersuchung aufgezeigt und die Bedeutung als Teil eines umfassenden Behandlungskonzeptes dargelegt.

Patienten und Methodik: Für die epidemiologische Untersuchung wurden in einer ländli-chen Hausarztpraxis sämtliche Patientinnen bezüglich Beinleiden untersucht. Die Studie zur Liposuktion umfasste die prä- und postoperative Untersuchung von 85 Patientinnen mittels Beschwerdefragebogen.

Ergebnisse: Bei 5 % aller Patientinnen einer Hausarztpraxis wurde ein Lipödem festgestellt. Mittels Liposuktion konnten bei 85 Patientinnen Schmerzen, Druckschmerz, Hämatomneigung und Schwellungsneigung signifi-kant vermindert und die Lebensqualität verbessert werden.

Schlussfolgerung: Das Lipödem ist eine relativ häufige Erkrankung der weiblichen Bevölkerung. Die Liposuktion stellt zusammen mit der prä- und postoperativen komplexen physikalischen Entstauungstherapie, einem Sportprogramm und der Behandlung einer begleitenden Adipositas sowie bedarfsweise einer psychologischen Unterstützung ein wirksames Behandlungskonzept dar.

Sie kann nur im Zusammenwirken mit diesen anderen Therapien erfolgreich sein und daher ist ein umfassender Therapieplan anzustreben.

Lymphedema: Diagnostic workup and management

Lymphedema is a localized form of tissue swelling resulting from excessive retention of lymphatic fluid in the interstitial compartment. It is caused by impaired lymphatic drainage. Lymphedema is a chronic progressive disease with serious physical and psychosocial implications. It can be challenging to diagnose, especially in obese patients and in those with coexisting venous disease. We performed PubMed and Google Scholar searches of the English-language literature (1966-2017) using the terms lymphedema, lymphedema management, and lymphatic complications. Relevant publications were manually reviewed for additional resources. There are currently no standard guidelines for the diagnosis of lymphedema. There is no cure yet for lymphedema, and the objective for management is to limit disease progression and prevent complications.

Sphingosine 1-phosphate receptor 1 regulates the directional migration of lymphatic endothelial cells in response to fluid shear stress

The endothelial cells that line blood and lymphatic vessels undergo complex, collective migration and rearrangement processes during embryonic development, and are known to be exquisitely responsive to fluid flow. At present, the molecular mechanisms by which endothelial cells sense fluid flow remain incompletely understood. Here, we report that both the G-protein-coupled receptor sphingosine 1-phosphate receptor 1 (S1PR1) and its ligand sphingosine 1-phosphate (S1P) are required for collective upstream migration of human lymphatic microvascular endothelial cells in an in vitro setting. These findings are consistent with a model in which signalling via S1P and S1PR1 are integral components in the response of lymphatic endothelial cells to the stimulus provided by fluid flow.

Lymph Vessel Thrombus Detection in Cervical Lymphedema: A Case Series

Although thrombosis in the terminal part of thoracic duct has been described in patients with head and neck cancer and upper vein thrombosis, normally medical imaging is not successful in depicting such lymphatic thrombosis. This case series is about three patients with acute onset of cervical lymphedema following minor trauma or exceptional physical strain. Using high-resolution ultrasound, it was possible to detect a thrombus formation in the terminal parts of the thoracic duct or the lymph duct. Within a few weeks all patients recovered without relapse for several years.

Persistent impairments 3 years after (neo)adjuvant chemotherapy for breast cancer: results from the MaTox project

Purpose

Although treatment for early breast cancer improved prognosis greatly, it can have significant long-term consequences, which must be considered during treatment decision.

Methods

453 patients with neoadjuvant or adjuvant treatment intention were recruited into the MaTox project within the prospective, multicentre, population-based German TMK cohort study (Tumour Registry Breast Cancer) between 2008 and 2009. Patient-reported outcomes (PROs) on 26 treatment-related symptoms were assessed via a specifically designed questionnaire at 4 weeks, 6 months, 18 months and 3 years after start of systemic treatment.

Results

The results show that alterations in smell, taste and appetite were clearly improved 3 years after treatment. In contrast, post-surgical symptoms, restrictions in memory/attention, musculoskeletal system and polyneuropathy worsened substantially over time and were persistent after 3 years: 78% of the patients recorded impairment in memory, 73% muscle pain, 67% pain at the operated site and 57% paraesthesia in fingers or toes. A logistic regression model showed that risk factors for developing persistent paraesthesia symptoms were age, early paraesthesia symptoms and taxane-based therapy.

Conclusions

Our data show that most patients with breast cancer have persistent impairments negatively influencing their daily life even 3 years after treatment. Furthermore, we highlight areas requiring special attention in follow-up care.

Electronic supplementary material

The online version of this article (doi:10.1007/s10549-017-4365-7) contains supplementary material, which is available to authorized users.

Evaluation of the Upper Limb Lymphatic System: A Prospective Lymphoscintigraphic Study in Melanoma Patients and Healthy Controls

BACKGROUND

Current research on the upper limb lymphatic system mainly studies breast cancer patients with unilateral lymphedema. Without preoperative lymphoscintigraphy, the contralateral limb is used as a control, assuming that it is functionally intact. Few lymphoscintigraphic studies investigate patients before any axillary surgery. The purpose of this study was to evaluate, through lymphoscintigraphy, the preoperative condition of the upper limb lymphatic system in melanoma patients and healthy controls.

METHODS

Two groups were studied: the study group (16 patients with trunk/upper limb melanoma candidates for axillary sentinel lymph node biopsy) and the control group (10 healthy volunteers). All subjects underwent upper limb lymphoscintigraphy. Lymphoscintigraphic images were classified into three patterns based on the tracer appearance time in the axillary nodes. Type I, 20 minutes; type II, 60 minutes; and type III, 120 minutes. Statistical analysis was used to assess the relationship between lymphoscintigraphic patterns and clinical variables and to compare patterns of distribution.

RESULTS

Lymphoscintigraphic patterns were asymmetric in 37.5 percent (study group) and 50 percent (control group). Type III was the most common pattern. There was no significant association between lymphoscintigraphic patterns and considered clinical variables. There was no significant difference in the lymphoscintigraphic pattern distribution of the two groups (p = 0.870).

CONCLUSION

The authors' findings show wide differences and an often "slow" tracer appearance time in patients with intact lymphatic system, questioning the use of contralateral limb as control and transportation time greater than 30 minutes as criteria for identification of lymphatic alterations.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Diagnostic, IV.

Therapeutic effects of hyaluronidase on acquired lymphedema using a newly developed mouse limb model

Acquired lymphedema is one of the most dreaded side effects of cancer treatment, such as surgical treatment or irradiation. However, due to the lack of appropriate animal models, there is no effective therapeutic method to cure acquired lymphedema. To develop a reproducible acquired lymphedema animal model, we devised a mouse hind limb model by removing a superficial inguinal lymph node, a popliteal lymph node, a deep inguinal lymph node, and the femoral lymphatic vessel. We measured the volume of lymphedematous leg and observed the change in level of hyaluronic acid (HA) and lymphangiogenic factors after injecting hyaluronidase. Our model showed the distinguishable swelling and the reliable symptoms compared to previously reported models. In the lymphedematous regions of our model, we confirmed that HA, a major component of extracellular matrix, accumulated to higher levels than in a normal mouse. This lymphedema volume was rapidly reduced by treating hyaluronidase. Following hyaluronidase injection, the lymphedematous region of our model resembled a normal hind limb. Our findings indicated that hyaluronidase promoted lymphangiogenesis on the lymphedematous limb. Based on hyaluronidase treatment in the lymphedematous region, this could potentially be a new therapeutic approach for acquired lymphedema mediated through the modification of the size of HA fragments. Impact statement In this manuscript, the essence of the work described in this manuscript involves the development of (1) a mouse limb model showing acquired lymphedema and (2) a potent therapeutic treatment using hyaluronidase to remedy acquired lymphedema in our model. In order to develop a reproducible acquired lymphedema animal model that reflects the most common symptoms experienced by lymphedema patients, we devised a mouse hind limb model by removing lymph nodes and lymphatics. Our model showed the distinguishable swelling and the reliable symptoms compared to previously reported models. In the lymphedematous regions of our model, we confirmed that hyaluronic acid (HA) accumulated to higher levels than in a normal mouse. This lymphedema volume was rapidly reduced by treating the lymphedematous leg with hyaluronidase, which also degraded high molecular weight HA to low molecular weight HA. Immunohistochemical analysis, quantitative real-time PCR analysis and lymphangioscintigraphy showed that hyaluronidase enhanced lymphangiogenesis in the lymphedematous limb.

Interaction between vascularized lymph node transfer and recipient lymphatics after lymph node dissection-a pilot study in a canine model

BACKGROUND

Vascularized lymph node transfer (VLNT) has become more widespread for surgical treatment of lymphedema. However, interaction between a transferred lymph node and the recipient lymphatic system in relieving lymphedema has not been identified. The aims of this study were to investigate anatomic changes in the lymphatic system in the forelimb of a canine after lymph node dissection and irradiation and to clarify the interaction between the transferred lymph node and recipient lymphatics.

MATERIALS AND METHODS

Two adult female mongrel canines were used for this exploratory study. The unilateral axillary and lower neck node dissections were performed, and 15-Gy irradiation was applied on postoperative day 3. After 1 y, a VLNT flap was harvested from the lower abdominal region and inset in the axilla with vascular anastomoses. The girth of each forelimb was determined with a tape measure at different time points. Indocyanine green fluorescence lymphography and lymphangiography were performed before and after each surgery to evaluate morphologic changes in the lymphatics.

RESULTS

Both canines revealed identical changes in the lymphatic system, but only one canine developed lymphedema. After lymph node dissection, a collateral lymphatic pathway formed a connection to the contralateral cervical node. After VLNT, an additional collateral pathway formed a connection to the internal mammary node via the transferred node in the axilla.

CONCLUSIONS

The findings suggest that the lymphatic system has a homing mechanism, which allows the severed lymphatic vessels to detect and connect to adjacent lymph nodes. VLNT may create new collateral pathways to relieve lymphedema.

Complex Decongestive Lymphatic Therapy With or Without Vodder II Manual Lymph Drainage in More Severe Chronic Postmastectomy Upper Limb Lymphedema: A Randomized Noninferiority Prospective Study

CONTEXT

Complex decongestive lymphatic therapy (CDT) has been the method of choice in conservative management of lymphedema. Although effective, it is time consuming and manual lymph drainage (MLD) usually requires skilled therapists.

OBJECTIVES

The purpose of this study was to compare the reduction in edema volume in more advanced (≥20% limb volume difference) postmastectomy arm lymphedema achieved by compression bandaging (CB) and physical exercises vs. the same management augmented by an additional 30 minutes of MLD (Vodder II method).

METHODS

Sixty postmastectomy women were randomly assigned to either the CB group or the CDT group. Of those, 51 women (26 within the CB group) completed 26 weeks of therapy (two weeks of the intensive phase and six months of the maintenance phase).

RESULTS

A decrease of limb volume (15.6% in the CB group and 13.8% in the CDT group), edema volume (47.2% and 47.4%, respectively), and limb-related volume change (14.7% and 12.5%) during the intensive phase were observed. This improvement remained constant in both groups after six months of maintenance therapy. The health-related quality of life (measured by the Lymphedema Questionnaire) similarly showed improvement in both groups, with a high level of treatment satisfaction.

CONCLUSION

These results indicate that parallel (immediate and delayed) results may be obtained by CDT without the use of Vodder MLD and CB may be an essential part of lymphedema management.

Vascular Anomalies in Pediatrics

A standardized classification system allows improvements in diagnostic accuracy. Multidisciplinary vascular anomaly centers combine medical, surgical, radiologic, and pathologic expertise. This collaborative approach tailors treatment and management of vascular anomalies for affected individuals.

Lymphedema prevalence and treatment benefits in cancer: impact of a therapeutic intervention on health outcomes and costs

Background

Lymphedema is a common complication of cancer therapeutics; its prevalence, treatment outcomes, and costs have been poorly defined. The objective of this study was to examine lymphedema prevalence among cancer survivors and to characterize changes in clinical outcomes and costs associated with a defined therapeutic intervention (use of a pneumatic compression devices [PCD]) in a representative, privately insured population.

Methods and Findings

Retrospective analysis of de-identified health claims data from a large national insurer for calendar years 2007 through 2013. Patients were required to have 12 months of continuous insurance coverage prior to PCD receipt (baseline), as well as a 12-month follow-up period. Analyses were performed for individuals with cancer-related lymphedema (n = 1,065). Lymphedema prevalence was calculated: number of patients with a lymphedema claim in a calendar year divided by total number of enrollees. The impact of PCD use was evaluated by comparing rates of a pre-specified set of health outcomes and costs for the 12 months before and after, respectively, PCD receipt. Lymphedema prevalence among cancer survivors increased from 0.95% in 2007 to 1.24% in 2013. PCD use was associated with decreases in rates of hospitalizations (45% to 32%, p<0.0001), outpatient hospital visits (95% to 90%, p<0.0001), cellulitis diagnoses (28% to 22%, p = 0.003), and physical therapy use (50% to 41%, p<0.0001). The average baseline health care costs were high ($53,422) but decreased in the year after PCD acquisition (−$11,833, p<0.0001).

Conclusions

Lymphedema is a prevalent medical condition that is often a defining attribute of cancer survivorship. The problem is associated with high health care costs; Treatment (in this instance, use of PCD) is associated with significant decreases in adverse clinical outcomes and costs.