Adipogenesis, fibrosis, and inflammation

Localised Objective Characterisation Assessment of Lymphoedema (LOCAL): Using High-Frequency Ultrasound, Bioelectrical Impedance Spectroscopy and Volume to Evaluate Superficial Tissue Composition

Lymphoedema tissue is characterised by excess free fluid and structural changes to the extracellular matrix (ECM) in the form of fibrotic and fatty deposition. These tissue characteristics are integral to the assessment of lymphoedema progression; however, clinicians and researchers often focus on changes in the free fluid, volume and function of lymphatic vasculature to inform practice. Subsequently, little is known about the effect of clinical interventions on lymphoedema tissue composition. This article presents a novel approach to classify lymphoedema tissue. The Localised Objective Characterisation Assessment of Lymphoedema (LOCAL) classification combines diagnostic and clinically meaningful objective assessment thresholds to infer lymphoedema pathophysiological changes in tissue layers. The LOCAL classification method was verified using data from fifteen women with unilateral breast cancer-related lymphoedema who were evaluated at three sites on each arm using high-frequency ultrasound (HFUS), bio-electrical impedance spectroscopy (BIS) and volume measurements. Participants exhibited an uneven distribution of volume between the proximal and distal segments of the arm (p = 0.023), with multiple tissue compositional categories observed across sites on the same limb (p < 0.001). The LOCAL method demonstrated utility in categorising a diverse range of lymphoedema tissue layer changes beyond what can be ascertained from whole-limb measures.

Molecular pathophysiology of secondary lymphedema

Lymphedema occurs as a result of lymphatic vessel damage or obstruction, leading to the lymphatic fluid stasis, which triggers inflammation, tissue fibrosis, and adipose tissue deposition with adipocyte hypertrophy. The treatment of lymphedema is divided into conservative and surgical approaches. Among surgical treatments, methods like lymphaticovenular anastomosis and vascularized lymph node transfer are gaining attention as they focus on restoring lymphatic flow, constituting a physiologic treatment approach. Lymphatic endothelial cells form the structure of lymphatic vessels. These cells possess button-like junctions that facilitate the influx of fluid and leukocytes. Approximately 10% of interstitial fluid is connected to venous return through lymphatic capillaries. Damage to lymphatic vessels leads to lymphatic fluid stasis, resulting in the clinical condition of lymphedema through three mechanisms: Inflammation involving CD4+ T cells as the principal contributing factor, along with the effects of immune cells on the VEGF-C/VEGFR axis, consequently resulting in abnormal lymphangiogenesis; adipocyte hypertrophy and adipose tissue deposition regulated by the interaction of CCAAT/enhancer-binding protein α and peroxisome proliferator-activated receptor-γ; and tissue fibrosis initiated by the overactivity of Th2 cells, leading to the secretion of profibrotic cytokines such as IL-4, IL-13, and the growth factor TGF-β1. Surgical treatments aimed at reconstructing the lymphatic system help facilitate lymphatic fluid drainage, but their effectiveness in treating already damaged lymphatic vessels is limited. Therefore, reviewing the pathophysiology and molecular mechanisms of lymphedema is crucial to complement surgical treatments and explore novel therapeutic approaches.

Time trend of breast cancer-related lymphedema according to body mass index

PURPOSE

To clarify how body mass index (BMI) affects the development and temporal trend of breast cancer-related lymphedema (BCRL).

METHODS

This is a prospective study in which patients with operable breast cancer were registered in a single institute between November 2009 and July 2010. The incidence of lymphedema at 1, 3, and 5 years after surgery was assessed according to BMI, and the trend of newly developed BCRL was examined. Obesity was defined as BMI ≥25 in accordance with the Japan Society for the Study of Obesity.

RESULTS

A total of 368 patients were included in this study. The multivariate analysis of the whole population showed that high BMI, axillary dissection, and radiotherapy remained as risk factors for BCRL. Patients with high BMI showed a significantly higher incidence of new lymphedema than those with low BMI at 1 year (p < 00.001) regardless of axillary procedures (39.1 % vs 16.3 % for axillary dissection; 15.6 % vs 1.5 % for sentinel lymph node biopsy) but not at 3 and 5 years. Once BCRL developed, patients with high BMI showed slow recovery and 50.0 % of the patients retained edema at 5 years while patients with low BMI showed rapid recovery and 26.7 % retained after 3 years (p = 0.04).

CONCLUSION

The preoperative BMI affected the incidence and temporal trend of BCRL regardless of axillary procedures or radiotherapy. Patients with high BMI should be given appropriate information about BCRL before surgery with careful follow-up for BCRL after treatment.

Characterization of Immune Cell Infiltration and Collagen Type III Disorganization in Human Secondary Lymphedema: A Case-control Study

Background

Secondary lymphedema (SL) affects 120 million people globally, posing a lifelong burden for up to 37% of cancer survivors. Chronic inflammation and progressive fibrosis are key drivers of SL, yet detailed characterization of immune cell subpopulations across lymphedema stages is lacking. This study aimed to investigate the immunologic profile of lymphedematous skin and its association with extracellular matrix changes, which could serve as clinical biomarkers or therapeutic targets.

Methods

This case-control study analyzed the skin from 36 patients with and without SL, using immunofluorescence to quantify T cells, B cells, macrophages, and their subpopulations. Collagen quantity and composition were examined using picrosirius red staining, and mast cell infiltration was assessed with toluidine blue staining. Early and late SL stages were compared to identify histomorphological and immunologic correlates of stage progression.

Results

We found a predominance of CD4+ T cells and mast cells in SL skin (1.4/mm² versus 1.0/mm², P < 0.01; 1.2/mm² versus 0.2/mm², P < 0.0001) and a higher ratio of collagen III to collagen I fibers (51.6% versus 75.0%, P < 0.001). M2 macrophages were more abundant in late-stage than in early-stage lymphedema (1.7/mm² versus 1.0/mm², P = 0.02).

Conclusions

This study demonstrated a shift toward CD4+ T cell and mast cell infiltration in SL skin, correlating with extracellular matrix disorganization and an altered collagen III/I ratio. These findings enhance our understanding of the cellular and morphological changes in SL, potentially guiding future diagnostic and therapeutic strategies.

Immunogenicity and tolerance induction in vascularized composite allotransplantation

Vascularized composite allotransplantation (VCA) is the transplantation of multiple tissues such as skin, muscle, bone, nerve, and vessels, as a functional unit (i.e., hand or face) to patients suffering from major tissue trauma and functional deficits. Though the surgical feasibility has been optimized, issues regarding graft rejection remains. VCA rejection involves a diverse population of cells but is primarily driven by both donor and recipient lymphocytes, antigen-presenting cells, macrophages, and other immune as well as donor-derived cells. In addition, it is commonly understood that different tissues within VCA, such as the skin, elicits a stronger rejection response. Currently, VCA recipients are required to follow potent and lifelong immunosuppressing regimens to maximize graft survival. This puts patients at risk for malignancies, opportunistic infections, and cancers, thereby posing a need for less perilous methods of inducing graft tolerance. This review will provide an overview of cell populations and mechanisms, specific tissue involved in VCA rejection, as well as an updated scope of current methods of tolerance induction.

Chiral Supramolecular Hydrogel Enhanced Transdermal Delivery of Sodium Aescinate to Modulate M1 Macrophage Polarization Against Lymphedema

Sodium aescinate (SA) shows great potential for treating lymphedema since it can regulate the expression of cytokines in M1 macrophages, however, it is commonly administered intravenously in clinical practice and often accompanied by severe toxic side effects and short metabolic cycles. Herein, SA-loaded chiral supramolecular hydrogels are prepared to prove the curative effects of SA on lymphedema and enhance its safety and transdermal transmission efficiency. In vitro studies demonstrate that SA- loaded chiral supramolecular hydrogels can modulate local immune responses by inhibiting M1 macrophage polarization. Typically, these chiral hydrogels can significantly increase the permeability of SA with good biocompatibility due to the high enantioselectivity between chiral gelators and stratum corneum and L-type hydrogels are found to have preferable drug penetration over D-type hydrogels. In vivo studies show that topical delivery of SA via chiral hydrogels results in dramatic therapeutic effects on lymphedema. Specifically, it can downregulate the level of inflammatory cytokines, reduce the development of fibrosis, and promote the regeneration of lymphatic vessels. This study initiates the use of SA for lymphedema treatment and for the creation of an effective chiral biological platform for improved topical administration.

Advances in lymphedema: An under-recognized disease with a hopeful future for patients

Lymphedema has traditionally been underappreciated by the healthcare community. Understanding of the underlying pathophysiology and treatments beyond compression have been limited until recently. Increased investigation has demonstrated the key role of inflammation and resultant fibrosis and adipose deposition leading to the clinical sequelae and associated reduction in quality of life with lymphedema. New imaging techniques including magnetic resonance imaging (MRI), indocyanine green lymphography, and high-frequency ultrasound offer improved resolution and understanding of lymphatic anatomy and flow. Nonsurgical therapy with compression, exercise, and weight loss remains the mainstay of therapy, but growing surgical options show promise. Physiologic procedures (lymphovenous anastomosis and vascularized lymph node transfers) improve lymphatic flow in the diseased limb and may reduce edema and the burden of compression. Debulking, primarily with liposuction to remove the adipose deposition that has accumulated, results in a dramatic decrease in limb girth in appropriately selected patients. Though early, there are also exciting developments of potential therapeutic targets tackling the underlying drivers of the disease. Multidisciplinary teams have developed to offer the full breadth of evaluation and current management, but the development of a greater understanding and availability of therapies is needed to ensure patients with lymphedema have greater opportunity for optimal care.

Liposuction for Advanced Lymphedema in a Multidisciplinary Team Setting in Australia: 5-Year Follow-Up

BACKGROUND

Liposuction for International Society of Lymphology late stage 2 or 3 limb lymphedema is an established surgical option to remove excessive adipose tissue deposition and has been performed in Australia since 2012 at the Australian Lymphoedema Education, Research, and Treatment (ALERT) Program of Macquarie University.

METHODS

Between May of 2012 and May of 2017, 72 patients with unilateral primary or secondary lymphedema of the arm or leg underwent suction-assisted lipectomy using the Brorson protocol. This prospective study presents 59 of these patients who had consented to research with a 5-year follow-up.

RESULTS

Of the 59 patients, 54 (92%) were women, 30 (51%) had leg lymphedema, and 29 (49%) had arm lymphedema. For patients with arm lymphedema, the median preoperative volume difference between the lymphedematous and the contralateral arm was 1061 mL, which was reduced to 79 mL 1 year after surgery and to 22 mL 5 years after surgery. For patients with leg lymphedema, the median preoperative volume difference was 3447 mL, which was reduced to 263 mL 1 year after surgery but increased to 669 mL 5 years after surgery.

CONCLUSION

Suction-assisted lipectomy is a long-term option for the management of selected patients with International Society of Lymphology late stage 2 or 3 limb lymphedema when conservative management can offer no further improvement.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Demystifying vascularized lymph node transfers and lymphatico-venous anastomoses

Lymphedema continues to be a widely prevalent condition with no definitive cure. It affects a wide range of patients across different ages and backgrounds. The significant burden of this chronic and debilitating condition necessitates more research and comprehensive healthcare coverage for affected patients. In developed countries, cancer survivors are disproportionality affected by this condition. Risk factors including lymph node dissections and radiation render many cancer patients more susceptible to the development of lymphedema. Part of the challenge with lymphedema care, is that it exits on a broad spectrum with significant variability of symptoms. Advances and broader availability of various imaging modalities continue to foster progress in lymphedema surgery. The conservative management of lymphedema remains the primary initial management option. However, lymphedema surgeries can provide significant hope and may pave the way for significant improvements in the quality-of-life for many patients afflicted by this progressive and enfeebling condition. Reductive and physiologic procedures are becoming an important part of the armamentarium of the modern plastic and reconstructive surgeon. Recent advances in physiologic lymphedema surgeries are accelerating their transition from experimental surgeries to broadly adopted and widely accepted procedures that can lead to major successes in the fight against this condition. Prophylactic lymphedema surgery also presents a promising choice for many patients and can help prevent lymphedema development in high-risk patients.

Extracellular matrix molecules associated with lymphatic vessels in health and disease

Lymphatic vessels (LyVs), responsible for fluid, solute, and immune cell homeostasis in the body, are closely associated with the adjacent extracellular matrix (ECM) molecules whose structural and functional impact on LyVs is currently more appreciated, albeit not entirely elucidated. These molecules, serving as a platform for various connective tissue cell activities and affecting LyV biology should be considered also as an integral part of the lymphatic system. Any alterations and changes in ECM molecules over the course of disease impair the function and structure of the LyV network. Remodeling of LyV cells, which are components of lymphatic vessel walls, also triggers alterations in ECM molecules and interstitial tissue composition. Therefore, in this review we aimed to present the current knowledge on ECM in tissues and particularly on molecules surrounding lymphatics in normal conditions and in disease.

The Function of T Cell Immunity in Lymphedema: A Comprehensive Review

Lymphedema is a debilitating disease characterized by extremity edema, fibroadipose deposition, impaired lymphangiogenesis, and dysfunctional lymphatics, often with lymphatic injury secondary to the treatment of malignancies. Emerging evidence has shown that immune dysfunction regulated by T cells plays a pivotal role in development of lymphedema. Specifically, Th1, Th2, Treg, and Th17 cells have been identified as critical regulators of pathological changes in lymphedema. In this review, our aim is to provide an overview of the current understanding of the roles of CD4+ T cells, including Th1, Th2, Treg, and Th17 subsets, in the progression of lymphedema and to discuss associated therapies targeting T cell inflammation for management of lymphedema.

Lymphedema and Kaposi sarcoma: A narrative review

BACKGROUND

Kaposi sarcoma (KS), due to HHV-8 infection is classified in 4 subtypes: epidemic, endemic, HIV-related and iatrogenic essentially after organ transplant. Lymphedema is a complication of KS. We reviewed the interactions between HHV-8 infection and lymphedema according an analysis of the literature.

MAIN BODY

HHV-8 can infect different types of cells, among them a privileged tropism for lymphatic endothelial cells. It induces multi-centric endothelial proliferation leading to the occlusion of lymphatic vascular lumen. Lymphatic obstruction progressively lead to the blockage of lymphatic drainage, lymph stasis and lymphedema. Lymphedema mostly involved the lower limb affected by KS. It can then develop simultaneously or after the appearance of KS lesions but also be the first sign of KS, a long time before KS skin lesion onset. Lymphedema diagnosis is clinical and lymphoscintigraphy can confirm it if necessary. Lymphedema may be associated with active lesions of KS or non-evolutive, with only cicatricial lesions. KS should be treated according to the KS subtype, aggressive form, with local or systemic treatments associating with causal treatment, such as HIV infection or reducing immuno-suppressive drugs in transplant patients. In most of the cases, KS treatment may slightly reduce (or not) lymphedema volume which remains a chronic disease. Lymphedema management should be associated in order to reduce the volume and then stabilizing it. Low-stretch bandage, elastic garments and skin care are the cornerstone of treatment.

CONCLUSION

Lymphedema is a frequent complication of KS, and may reveal KS or occurs throughout its course. Association of KS and lymphedema must be known because lymphedema is a chronic disease affecting the quality of life. Beyond the treatment of KS, its management must be specific including a long follow-up to optimize the patient's observance required to maintain the best lymphedema control.

Tissue Dielectric Constant and Skin Stiffness Relationships in Lower Extremity Lymphedema

Background: Lower extremity lymphedema or edema (LELE) may progressively transition from a state of excess tissue fluid to increased fat accumulation and collagen deposition, with tissue fibrosis and hardening. Such changes may lead to altered tissue water holding and thereby impact tissue dielectric constant (TDC). This study seeks to evaluate the relationship between TDC and tissue indentation force (TIF) in patients with LELE and assess the utility of the leg/arm TDC ratio (LAR) as an indicator of LELE. Methods and Results: Thirty females (49-91 years) with previously diagnosed LELE were evaluated during a scheduled session. TDC and TIF were measured 8 cm proximal to the medial malleolus on the medial and lateral aspects of both legs and on one forearm 8 cm distal to the antecubital fossa. The TDC-TIC relationship and the LAR were subsequently determined. Main results showed an absence of a significant correlation between TDC and TIF on medial or lateral leg sites but a positive correlation on the normal forearm site. Further, LAR values exceeded the published proposed threshold of 1.35 for 29/30 patients when using medial-side TDC values and 28/30 patients when using lateral-side TDC values. Conclusions: Findings suggest that for patients with LELE, TDC values are significantly elevated on medial and lateral standardized sites. The LAR determined using either medial or lateral sites that are similar to each other and have values consistent with a lymphedema threshold of 1.35. In edematous legs of the type evaluated herein, there is no apparent relationship between TDC values and indentation force.

Analysis of CD4+ T-helper-associated hub gene signature and immune dysregulation via RNA-sequencing data in a mouse tail model of lymphedema

Background

T-helper cells play an essential role in the progression of lymphedema. This study aimed to explore the biological significance of T-helper cell-associated genes (THAGs) in a mouse tail model of lymphedema by RNA-sequencing (RNA-seq) data.

Methods

The expression profiles of a murine model of secondary lymphedema were obtained from European Nucleotide Archive (ENA) database. Differentially expressed genes (DEGs) were screened and the enrichment analysis of DEGs was conducted. THAGs were constructed by crossing the T-helper-related gene sets obtained from Molecular Signatures Database with DEGs. Protein-protein interaction (PPI) network analysis was utilized to establish T-helper-associated hub genes (THAHGs). Single-sample gene set enrichment analysis (ssGSEA) was employed to decipher differences in immune cell infiltration. The correlation between THAHGs and immune infiltration was calculated by Pearson correlation analysis. Receiver operating characteristic (ROC) curves of THAHGs were drawn to evaluate their diagnostic properties. Additionally, potential drugs and upstream transcription factors (TFs) were predicted based on THAHGs.

Results

Enrichment analysis showed that lymphedematous tissue presented higher activation of biological process (BP) of T-helper 1 (Th1), T-helper 2 (Th2), T-helper 17 (Th17). The immune infiltration analysis further calculated that the relative immune abundance of follicular B cells, memory B cells, M1 macrophage, and CD4+ Tm cells was significantly elevated while the relative immune abundance of neutrophils and plasma cells were down-regulated in lymphedema. We established a list of THAHGs consisting of eight hub genes, compassing Cd4, Foxp3, Irf4, Ccr6, Il12rb1, Batf, Il1b, Cd74. THAHGs were shown to be significantly interrelated and related to immune infiltration by Pearson correlation analysis. ROC curves showcased that the area under curve (AUC) values of THAHGs were larger than 0.70. Gata3 was the most potential TF and thalidomide might be the immunoregulatory drug for lymphedema based on THAHGs.

Conclusions

Biological pathways associated with T-helpers were significantly enriched in mouse lymphedema tissue. The relative immune infiltration abundance of M1 macrophage, CD4+ Tm cells, and T-helper cells was higher in the lymphedema group. Besides, we identified the THAHGs containing eight genes, namely, Cd4, Foxp3, Irf4, Ccr6, Il12rb1, Batf, Il1b, and Cd74. The THAHGs were closely correlated with immune infiltration results and with good diagnostic properties.

Utilization of Noncontrast Magnetic Resonance Lymphangiography for Selection of Effective Surgical Method in Breast Cancer-Related Lymphedema

Background and Objectives: When considering surgery for patients with breast cancer-related lymphedema (BCRL), it is crucial to determine which surgery will be most effective for the patient and establish the indications for each surgery. Our study retrospectively compared the results of preoperative noncontrast MR lymphangiography (NMRL) performed on the lymphedematous limb of patients before surgery, with the aim of analyzing whether preoperative NMRL can be used as a criterion for determining the type of surgery. Materials and Methods: From January 2020 to June 2022, a total of 138 patients with lymphedema underwent surgery at Seoul National University Bundang Hospital. All patients underwent preoperative NMRL imaging and were classified into stages 1-3 based on the MRI severity index using the authors' previous reference. Three types of surgery, LVA, LVA + liposuction, and LVA + VLNT, were conducted on all patients. The effectiveness of the surgery was evaluated one year postoperatively using the interlimb volume difference before and after surgery, the fluid volume of the edematous limb measured by bioimpedance spectroscopy, and the subjective satisfaction of the patients through the Lymph Q questionnaire. Results: In this study, out of a total of 138 patients, 26 (19%) were MRI stage 1, 62 (45%) were stage 2, and 50 (36%) were stage 3. Of the 83 patients who underwent LVA surgery, the greatest decrease in interlimb volume difference was observed in stage 2 patients, and subjective satisfaction was also the most effective in stage 2. In the case of LVA + liposuction patients, a significant volume decrease and a high satisfaction were observed in stage 3 patients. In the case of LVA + VLNT patients, there was no difference in volume decrease according to the stage, but a greater decrease in body fluid volume was observed as the MRI severity index score increased through BIA. Conclusions: In conclusion, this study demonstrates that NMRL imaging is a useful modality for determining the most effective surgical method and predicting the surgical outcome in patients with lymphedema. This highlights the importance of using NMRL in the treatment planning of lymphedema patients.

Lipedema: What we don't know

BACKGROUND

Lipedema is a loose connective tissue disease characterized by a disproportionate accumulation of adipose tissue in the limbs of women. Despite its incidence of 10-20%, lipedema is often underdiagnosed and misdiagnosed.

OBJECTIVES

This review aims to outline current, available evidence regarding this enigmatic syndrome and gives a synopsis of the subjects that are still unknown.

MATERIALS AND METHODS

PubMed and Embase searches were conducted to identify relevant articles on lipedema pathophysiology, clinical presentation, diagnosis, and treatment.

RESULTS

Lipedema can be considered a disease of the adipocytes or a circulatory disorder of the lymphatics. The relationship between lymphatics and adipose tissue remains controversial. The clinical distinction between lipedema, lymphedema, phlebolymphedema, and lipolymphedema can be difficult. Diagnoses often coexist, further complicating the diagnosis of lipedema, which is currently made on clinical grounds alone. The value of diagnostic imaging studies is unclear. Liposuction appears to be an effective treatment and significantly improves symptoms.

CONCLUSION

Diagnosing lipedema remains a challenge due to its heterogeneous presentation, co-existing diseases, and lack of objective diagnostic imaging. Further directions for research include the effect of excess skin resection surgery on lymphatic drainage.

The emerging importance of lymphatics in health and disease: an NIH workshop report

The lymphatic system (LS) is composed of lymphoid organs and a network of vessels that transport interstitial fluid, antigens, lipids, cholesterol, immune cells, and other materials in the body. Abnormal development or malfunction of the LS has been shown to play a key role in the pathophysiology of many disease states. Thus, improved understanding of the anatomical and molecular characteristics of the LS may provide approaches for disease prevention or treatment. Recent advances harnessing single-cell technologies, clinical imaging, discovery of biomarkers, and computational tools have led to the development of strategies to study the LS. This Review summarizes the outcomes of the NIH workshop entitled "Yet to be Charted: Lymphatic System in Health and Disease," held in September 2022, with emphasis on major areas for advancement. International experts showcased the current state of knowledge regarding the LS and highlighted remaining challenges and opportunities to advance the field.

Therapeutic Lymphangiogenesis Is a Promising Strategy for Secondary Lymphedema

Secondary lymphedema is caused by lymphatic insufficiency (lymphatic drainage failure) following lymph node dissection during the surgical treatment or radiation therapy of breast or pelvic cancer. The clinical problems associated with lymphedema are reduced quality of life in terms of appearance and function, as well as the development of skin ulcers, recurrent pain, and infection. Currently, countermeasures against lymphedema are mainly physical therapy such as lymphatic massage, elastic stockings, and skin care, and there is no effective and fundamental treatment with a highly recommended grade. Therefore, there is a need for the development of a fundamental novel treatment for intractable lymphedema. Therapeutic lymphangiogenesis, which has been attracting attention in recent years, is a treatment concept that reconstructs the fragmented lymphatic network to recover lymphatic vessel function and is revolutionary to be a fundamental cure. This review focuses on the translational research of therapeutic lymphangiogenesis for lymphedema and outlines the current status and prospects in the development of therapeutic applications.

Comparison of the Effectiveness of Liposuction for Lower Limb versus Upper Limb Lymphedema

OBJECTIVE

Liposuction is the most frequently performed debulking procedure in patients with lymphedema. However, it remains uncertain whether liposuction is equally effective for upper extremity lymphedema (UEL) and lower extremity lymphedema (LEL). In this study, we retrospectively compared the effectiveness of liposuction according to whether it was performed for LEL or UEL, and identified factors associated with outcomes.

MATERIALS AND METHODS

All patients had been treated at least once by lymphovenous anastomosis or vascularized lymphatic transplant before liposuction but without sufficient volume reduction. The patients were divided into an LEL group and a UEL group, and then subdivided further according to whether they completed their planned compression therapy into an LEL compliance group, an LEL non-compliance group, a UEL compliance group, and a UEL non-compliance group. The reduction rates in LEL (REL) and in UEL (REU) were compared between the groups.

RESULTS

In total, 28 patients with unilateral lymphedema were enrolled (LEL compliance group, n = 12; LEL non-compliance group, n = 6; UEL compliance group, n = 10; UEL non-compliance group, n = 0). The non-compliance rate was significantly higher in the LEL group than in the UEL group (p = 0.04). REU was significantly higher than REL (100.1 ± 37.3% vs. 59.3 ± 49.4%; p = 0.03); however, there was no significant difference between REL in the LEL compliance group (86 ± 31%) and REU in the UEL group (101 ± 37%) (p = 0.32).

CONCLUSION

Liposuction seems to be more effective in UEL than in LEL, probably because the compression therapy required for management after liposuction is easier to implement for UEL. The lower pressure and smaller coverage area required for postoperative management after liposuction in the upper limb may explain why liposuction is more effective in UEL than in LEL.

Adipose Tissue in Lymphedema: A Central Feature of Pathology and Target for Pharmacologic Therapy

Lymphedema is a chronic condition of impaired lymphatic flow that results in limb swelling and debilitation. The pathophysiology of lymphedema is characterized by lymphatic stasis that triggers inflammation, fibrosis, and adipose tissue deposition in the extremities. Most often, this condition occurs in cancer survivors in the years after treatment with combinations of surgery, radiation, or chemotherapy, with the major risk factor being lymph node dissection. Interestingly, obesity and body mass index are independent risk factors for development of lymphedema, suggesting interactions between adipose and lymphatic tissue biology. Currently, treatment of lymphedema involves palliative approaches, including compression garments and physical therapy, and surgical approaches, including liposuction, lymphovenous bypass, and vascularized lymph node transfer. Emerging lymphedema therapies that focus on weight loss or reducing inflammation have been tested in recent clinical trials, yielding mixed results with no effect on limb volumes or changes in bioimpedance measurements. These studies highlight the need for novel therapeutic strategies that target the driving forces of lymphedema. In this light, animal models of lymphedema demonstrate a role of adipose tissue in the progression of lymphedema and suggest these processes may be targeted in the treatment of lymphedema. Herein, we review both conventional and experimental therapies for lymphedema as well as the defining characteristics of its pathophysiology. We place emphasis on the aberrant fibroadipose tissue accumulation in lymphedema and propose a new approach to experimental treatment at the level of adipocyte metabolism.

The Vicious Circle of Stasis, Inflammation, and Fibrosis in Lymphedema

SUMMARY

Lymphedema is a progressive disease of the lymphatic system arising from impaired lymphatic drainage, accumulation of interstitial fluid, and fibroadipose deposition. Secondary lymphedema resulting from cancer treatment is the most common form of the disease in developed countries, affecting 15% to 40% of patients with breast cancer after lymph node dissection. Despite recent advances in microsurgery, outcomes remain variable and, in some cases, inadequate. Thus, development of novel treatment strategies is an important goal. Research over the past decade suggests that lymphatic injury initiates a chronic inflammatory response that regulates the pathophysiology of lymphedema. T-cell inflammation plays a key role in this response. In this review, the authors highlight the cellular and molecular mechanisms of lymphedema and discuss promising preclinical therapies.

Gluteal lymphoedema associated with lower extremity lymphoedema: A preliminary study with indocyanine green lymphography and magnetic resonance imaging

INTRODUCTION

Indocyanine green (ICG) lymphography studies have identified that one in three to five patients with cancer-related lower extremity lymphoedema (LEL) demonstrated dermal backflow extending to the gluteal region. This study aimed to further characterize gluteal lymphoedema using contemporaneous magnetic resonance imaging (MRI).

PATIENTS AND METHODS

Twenty-eight patients with unilateral advanced LEL who underwent both ICG lymphography and MRI prior to any surgical procedure were included in this study. The patients were divided into two groups with/without gluteal lymphoedema by the presence of dermal backflow on ICG lymphography. MRI was used to evaluate tissue changes.

RESULTS

Ten patients demonstrated gluteal lymphoedema on ICG lymphography and had a higher incidence of skin hypertrophy in the gluteal region. However, no difference in excess leg volume was found between the two groups. A trend of increasing gluteal subcutaneous tissue in the affected side was identified in patients with gluteal lymphoedema with a median increase of 20% compared with an 11% increase in the non-gluteal lymphoedema group. The excess gluteal subcutaneous tissue was positively correlated to ipsilateral excess leg volume.

CONCLUSION

The gluteal lymphoedema group on ICG lymphography had skin thickening in the gluteal region and was likely identified in the secondary cancer-related group. Surgical and conservative management options for gluteal lymphoedema need to be considered in advanced LEL.

Axillary reverse mapping in breast cancer: An overview

Standard operative management for breast carcinoma has significantly shifted from extensive procedures to minor interventions.Although axillary dissection was a fundamental component of operative management, sentinel biopsy is an actual process for axillary staging. Axillary dissection may be postponed for cases that have negative SLNs or 1 or 2 infiltrated lymph nodes undergoing breast or axillary radiation. Contrarily, axillary dissection is still the conventional management for patients with clinically positive nodes.Arm lymphedema is a frequent and overwhelming complication of axillary dissection, with a worse impact on the patient's life.Axillary reverse mapping was recently introduced to map and conserve the lymph drain of the upper limb throughout axillary dissection or sentinel biopsy. A technique based on the theory that the breast's lymphatic drainage differs from those that drain the arm, so preserving lymphatic drainage of the upper limb can prevent lymphedema, thereby not raising the risk of axillary recurrence.Therefore, this technique is the reverse of sentinel biopsy, which remove the lymph nodes that drain the breast.

Thyroid Hormone Ameliorates Lymphedema by Suppressing Adipogenesis in a Murine Lymphedema Model

Background: Exogenous supplementation of thyroid hormone could inhibit excessive fat deposition in lymphedema tissue by suppressing adipogenesis. Methods and Results: Cell viability, adipogenic differentiation, and mRNA expression were measured in 3T3-L1 preadipocytes treated with L-thyroxine. Twelve mice were divided into control and L-thyroxine groups. Two weeks after lymphedema was surgically induced, the experimental mice were fed L-thyroxine for 4 weeks. Tail volume and body weight were measured, and 6 weeks after the surgery, tail skin and subcutaneous tissue were harvested for histopathologic examination and protein isolation. In 3T3-L1 cells, treatment with 10-500 μM L-thyroxine did not affect cell viability. Eight days after induction of adipogenic differentiation, lipid accumulation decreased significantly in the 50 and 100 μM L-thyroxine groups (p < 0.001). mRNA levels of peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer binding protein α (C/EBPα), and fatty acid-binding protein 4 (FABP4) decreased significantly in the 100 μM L-thyroxine group compared with the control group (p = 0.017). Lymphedema tails treated with L-thyroxine exhibited decreased volume (p = 0.028) and thickness of dermal and subcutaneous tissue (p = 0.01) and increased vascular endothelial growth factor-C protein expression (p = 0.017) compared with the control. Conclusion: Thyroid hormone therapy inhibits the adipogenesis of 3T3-L1 cells in vitro and decreases the volume of murine lymphedema tail in vivo. These findings suggest that thyroid hormone therapy could be used to treat lymphedema.

Genital Lymphedema after Cancer Treatment: A Narrative Review

Genital lymphedema may affect males and females after cancer treatment (gynecological, such as cervical, uterine or ovarian, melanoma, prostate, anus…). It is frequently associated with lower limb lymphedema, and is responsible for discomfort, cosmetic disfigurement and functional disturbances. Impacts on body image, sexual function and quality of life are major, and difficult to explore because cancer treatment itself and lymphedema are so closely interwoven. Local complications, e.g., papillomatosis, warty growth, lymph vesicles with embarrassing lymph oozing and cellulitis, may occur. Usual lymphedema therapies, like bandaging and elastic compression, are poorly adapted to these sites. Surgery, essentially based on cutaneous resection techniques, is the primary symptomatic treatment; it achieves good efficacy, in adults and children, with possible recurrence requiring reintervention.

Is Lymphedema a Systemic Disease? A Paired Molecular and Histological Analysis of the Affected and Unaffected Tissue in Lymphedema Patients

Secondary lymphedema is a chronic, debilitating disease and one of the most common side effects of oncologic surgery, substantially decreasing quality of life. Despite the progress conducted in lymphedema research, the underlying pathomechanisms remain elusive. Lymphedema is considered to be a disease affecting an isolated extremity, yet imaging studies suggest systemic changes of the lymphatic system in the affected patients. To evaluate potential systemic manifestations in lymphedema, we collected matched fat and skin tissue from the edematous and non-edematous side of the same 10 lymphedema patients as well as anatomically matched probes from control patients to evaluate whether known lymphedema manifestations are present systemically and in comparison to health controls. The lymphedematous tissue displayed various known hallmarks of lymphedema compared to the healthy controls, such as increased epidermis thickness, collagen deposition in the periadipocyte space and the distinct infiltration of CD4+ cells. Furthermore, morphological changes in the lymphatic vasculature between the affected and unaffected limb in the same lymphedema patient were visible. Surprisingly, an increased collagen deposition as well as CD4 expression were also detectable in the non-lymphedematous tissue of lymphedema patients, suggesting that lymphedema may trigger systemic changes beyond the affected extremity.

Acquired lymphedema: Molecular contributors and future directions for developing intervention strategies

Lymphedema is a debilitating chronic disease that mostly develops as an adverse reaction to cancer treatment modalities such as chemotherapy, surgery, and radiotherapy. Lymphedema also appears to be a deteriorating consequence of roundworm infections, as best represented by filariasis. According to its origin, lymphedema is classified as primary lymphedema and acquired lymphedema. The latter is an acquired condition that, hitherto, received a considerably low attention owing to the less number of fatal cases been reported. Notably, despite the low mortality rate in lymphedema, it has been widely reported to reduce the disease-free survival and thus the quality of life of affected patients. Hence, in this review, we focused on acquired lymphedema and orchestration of molecular interplays associated with either stimulation or inhibition of lymphedema development that were, in vast majority, clearly depicted in animal models with their specific and distinct technical approaches. We also discussed some recent progress made in phytochemical-based anti-lymphedema intervention strategies and the specific mechanisms underlying their anti-lymphedema properties. This review is crucial to understand not only the comprehensive aspects of the disease but also the future directions of the intervention strategies that can address the quality of life of affected patients rather than alleviating apparent symptoms only.

Lymphatics in Cardiovascular Physiology

The lymphatic vessels play an essential role in maintaining immune and fluid homeostasis and in the transport of dietary lipids. The discovery of lymphatic endothelial cell-specific markers facilitated the visualization and mechanistic analysis of lymphatic vessels over the past two decades. As a result, lymphatic vessels have emerged as a crucial player in the pathogenesis of several cardiovascular diseases, as demonstrated by worsened disease progression caused by perturbations to lymphatic function. In this review, we discuss the major findings on the role of lymphatic vessels in cardiovascular diseases such as hypertension, obesity, atherosclerosis, myocardial infarction, and heart failure.

Enhancing lymphangiogenesis and lymphatic drainage to vascularized lymph nodes with nanofibrillar collagen scaffolds

BACKGROUND

This study investigated the effect of nanofibrillar collagen scaffold (BioBridge) implantation from the affected limb to the unaffected contralateral femoral vein or lymph node in a rat model.

METHODS

Hind limb lymphedema in Lewis rats was created with lymphadenectomy and inguinal circumcision without radiation. The volumetric difference (greater than 5%) using computed tomography and indocyanine green fluorescence evaluated the progress of lymphedema at 4 weeks. The lymphedema rats have separated into Group I: Controls; Group II: implanted BioBridge to the contralateral femoral vein; and Group III: implanted BioBridge to the contralateral inguinal lymph node.

RESULTS

A total of 14 of 30 (46.7%) rats developed hind limb lymphedema with a mean volume difference of 5.83 ± 0.99% and showed diffuse dermal backflow at 4 weeks postlymphadenectomy. Four weeks postimplantation of BioBridge, the mean volumetric difference was 5.62 ± 2.11%, 4.97 ± 0.59%, and -2.47 ± 2.37% in Group I, II, and III, respectively (p < 0.05). The dermal backflow on the affected limb increased in Groups I and II but decreased in Group III.

CONCLUSIONS

Implantation of BioBridge from the affected limb to the contralateral inguinal lymph node significantly reduced the hind limb lymphedema at 4 weeks.

Use of Dual-Energy X-Ray Absorptiometry to Assess Soft Tissue Composition in Breast Cancer Survivors With and Without Lymphedema

Background: In patients with lymphedema (LE), in addition to hand dominance, between-group comparisons of interlimb soft tissue differences need to account for differences in whole-body adiposity, measured directly by dual energy X-ray absorptiometry (DXA) or indirectly by body mass index. No study has evaluated the effects of hand dominance and whole-body adiposity on limb composition in patients with LE. This study's purpose was to compare soft tissue composition of affected and unaffected limbs of women with breast cancer, who did and did not have LE, controlling for dominance and percent body fat. Methods and Results: Whole-body DXA scans were acquired and included measures of percent body fat, upper limb total mass, upper limb fat mass, and upper limb fat-free mass. Participants were classified into one of three groups: women without LE; women with only subjective LE; and women with objective signs of LE at the time of assessment. Differences among the LE groups were evaluated using analysis of variance (ANOVA) and Chi-square analyses. Analysis of covariance (ANCOVA) was used to control for percent body fat and for the affected limb dominance. Compared to women without LE, women with objective signs of LE have greater total limb mass, fat mass, and fat-free mass in their affected limbs, independent of affected side dominance and percent body fat. In addition, the interlimb differences in total mass, fat mass, and fat-free mass were greater for the women with objective signs of LE, compared to the other two groups. Conclusions: DXA is useful in identifying soft tissue changes in patients with LE. Given that limb circumferences measure only changes in limb volume and that bioimpedance provides estimates of extracellular fluid, DXA has the advantage of being able to estimate the volumes of specific tissues in the limb.

Current Advancements in Animal Models of Postsurgical Lymphedema: A Systematic Review

Significance: Secondary lymphedema is a debilitating disease caused by lymphatic dysfunction characterized by chronic swelling, dysregulated inflammation, disfigurement, and compromised wound healing. Since there is no effective cure, animal model systems that support basic science research into the mechanisms of secondary lymphedema are critical to advancing the field. Recent Advances: Over the last decade, lymphatic research has led to the improvement of existing animal lymphedema models and the establishment of new models. Although an ideal model does not exist, it is important to consider the strengths and limitations of currently available options. In a systematic review adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we present recent developments in the field of animal lymphedema models and provide a concise comparison of ease, cost, reliability, and clinical translatability. Critical Issues: The incidence of secondary lymphedema is increasing, and there is no gold standard of treatment or cure for secondary lymphedema. Future Directions: As we iterate and create animal models that more closely characterize human lymphedema, we can achieve a deeper understanding of the pathophysiology and potentially develop effective therapeutics for patients.

Current Understanding of Pathological Mechanisms of Lymphedema

Significance: Lymphedema is a common disease that affects hundreds of millions of people worldwide with significant financial and social burdens. Despite increasing prevalence and associated morbidities, the mainstay treatment of lymphedema is largely palliative without an effective cure due to incomplete understanding of the disease. Recent Advances: Recent studies have described key histological and pathological processes that contribute to the progression of lymphedema, including lymphatic stasis, inflammation, adipose tissue deposition, and fibrosis. This review aims to highlight cellular and molecular mechanisms involved in each of these pathological processes. Critical Issues: Despite recent advances in the understanding of the pathophysiology of lymphedema, cellular and molecular mechanisms underlying the disease remains elusive due to its complex nature. Future Directions: Additional research is needed to gain a better insight into the cellular and molecular mechanisms underlying the pathophysiology of lymphedema, which will guide the development of therapeutic strategies that target specific pathology of the disease.

Single-cell RNA sequencing of subcutaneous adipose tissues identifies therapeutic targets for cancer-associated lymphedema

Cancer-associated lymphedema frequently occurs following lymph node resection for cancer treatment. However, we still lack effective targeted medical therapies for the treatment or prevention of this complication. An in-depth elucidation of the cellular alterations in subcutaneous adipose tissues of lymphedema is essential for medical development. We performed single-cell RNA sequencing of 70,209 cells of the stromal vascular fraction of adipose tissues from lymphedema patients and healthy donors. Four subpopulations of adipose-derived stromal cells (ASCs) were identified. Among them, the PRG4⁺/CLEC3B⁺ ASC subpopulation c3 was significantly expanded in lymphedema and related to adipose tissue fibrosis. Knockdown of CLEC3B in vitro could significantly attenuate the fibrogenesis of ASCs from patients. Adipose tissues of lymphedema displayed a striking depletion of LYVE⁺ anti-inflammatory macrophages and exhibited a pro-inflammatory microenvironment. Pharmacological blockage of Trem1, an immune receptor predominantly expressed by the pro-inflammatory macrophages, using murine LR12, a dodecapeptide, could significantly alleviate lymphedema in a mouse tail model. Cell–cell communication analysis uncovered a perivascular ligand-receptor interaction module among ASCs, macrophages, and vascular endothelial cells. We provided a comprehensive analysis of the lineage–specific changes in the adipose tissues from lymphedema patients at a single-cell resolution. CLEC3B was found to be a potential target for alleviating adipose tissue fibrosis. Pharmacological blockage of TREM1 using LR12 could serve as a promising medical therapy for treating lymphedema.

Current Mechanistic Understandings of Lymphedema and Lipedema: Tales of Fluid, Fat, and Fibrosis

Lymphedema and lipedema are complex diseases. While the external presentation of swollen legs in lower-extremity lymphedema and lipedema appear similar, current mechanistic understandings of these diseases indicate unique aspects of their underlying pathophysiology. They share certain clinical features, such as fluid (edema), fat (adipose expansion), and fibrosis (extracellular matrix remodeling). Yet, these diverge on their time course and known molecular regulators of pathophysiology and genetics. This divergence likely indicates a unique route leading to interstitial fluid accumulation and subsequent inflammation in lymphedema versus lipedema. Identifying disease mechanisms that are causal and which are merely indicative of the condition is far more explored in lymphedema than in lipedema. In primary lymphedema, discoveries of genetic mutations link molecular markers to mechanisms of lymphatic disease. Much work remains in this area towards better risk assessment of secondary lymphedema and the hopeful discovery of validated genetic diagnostics for lipedema. The purpose of this review is to expose the distinct and shared (i) clinical criteria and symptomatology, (ii) molecular regulators and pathophysiology, and (iii) genetic markers of lymphedema and lipedema to help inform future research in this field.

Lymphedema and Obesity

Lymphedema results from inadequate lymphatic function. Extreme obesity can cause lower extremity lymphedema, termed "obesity-induced lymphedema (OIL)." OIL is a form of secondary lymphedema that may occur once an individual's body mass index (BMI) exceeds 40. The risk of lymphatic dysfunction increases with elevated BMI and is almost universal once BMI exceeds 60. Obesity has a negative impact on lymphatic density in subcutaneous tissue, lymphatic endothelial cell proliferation, lymphatic leakiness, collecting-vessel pumping capacity, and clearance of macromolecules. Lymphatic fluid unable to be taken up by lymphatic vessels results in increased subcutaneous adipose deposition, fibrosis, and worsening obesity. Individuals with OIL are in an unfavorable cycle of weight gain and lymphatic injury. The fundamental treatment for OIL is weight loss.

Effects of diet-induced obesity in the development of lymphedema in the animal model: A literature review

BACKGROUND

Obesity poses deleterious consequences on every organ system, especially the lymphatic network. However, the underlying cellular mechanisms through which obesity causes lymphatic dysfunction remains unclear. We aimed to summarize experimental studies that evaluated the effect of obesity on the lymphatic system on animal models.

METHODS

We used the following terms to search the Ovid EMBASE, Ovid MEDLINE(R), Cochrane, and Scopus databases: "lymphedema", "lymphatic diseases", "lymphatic system/complications* ", "lymphatic system/injuries* ", "lymphatic system/abnormalities* ", AND "obesity/complications* ", "diet/high-fat", "adipogenesis" and "lipid metabolism disorder". From a total of 166 articles identified in the initial search, 13 met our eligibility criteria.

RESULTS

Long-term exposure to high-fat diet in mice demonstrated significant amount of adipose tissue deposition which sets off an inflammatory cascade resulting in disruption of the chemokine gradient, inhibition of lymphangiogenesis, and changes in gene expression of lymphatic endothelial cells, that alter vessel permeability and induce cell death. Reduced contractile properties of lymphatic collectors, dilated capillaries, increased tissue pressure, and reduced hydraulic conductivity collectively contribute to reduced impaired lymphatic drainage. Aerobic exercise has shown reversal of lymphatic dysfunction in the obese and pharmacological interventions targeting T-cells, iNOS and VEGFR-3 signaling have the potential to combat acquired lymphedema.

CONCLUSION

Scientists should focus their future experiments on developing therapies that regulate expression of T-cell derived cytokines and VEGFR-3 expression whereas clinicians are urged to counsel their patients to reduce weight through aerobic exercise.

Liposuction and Controlled Compression Therapy Reduce the Erysipelas Incidence in Primary and Secondary Lymphedema

BACKGROUND

Skin infections are a recurring problem for people with lymphedema, and lymphedema has been proven to be the single most important risk factor for developing erysipelas in the leg. This study aimed to determine whether liposuction for late-stage lymphedema reduces the rate of erysipelas in lower extremity lymphedema.

METHODS

One-hundred twenty-four patients with a median age of 49 years who had liposuction and controlled compression therapy for lower extremity lymphedema were included. Excess volumes were calculated before and after surgery. Median preoperative and postoperative patient years at risk were 11 and 5 years, respectively.

RESULTS

With a total of 1680 preoperative person years at risk and 335 bouts of erysipelas experienced in 64 patients, the preoperative incidence rate was 0.20 bouts per person per year, and the period prevalence was 52%. Postoperatively, the patients were followed over a total of 763 person years at risk, and 28 patients experienced a total of 53 bouts of erysipelas, resulting in a postoperative incidence rate of 0.07 bouts per person per year, and a period prevalence of 23%. This represents a 65% decrease in the erysipelas incidence rate (P < 0.001). The preoperative median excess volume of 3158 ml was reduced with a median of 100% (P < 0.0001).

CONCLUSIONS

Liposuction and controlled compression therapy significantly reduce the risk for erysipelas in lower extremity lymphedema and completely reduces the excess volume. This finding is similar to our previous research including patients with upper extremity lymphedema.

The Combination of Lymph Node Transfer and Excisional Procedures in Bilateral Lower Extremity Lymphedema: Clinical Outcomes and Quality of Life Assessment with Long-Term Follow-Up

Background: Bilateral lower extremity lymphedema is a rare and invalidating condition that poses a great challenge to the scientific community, and deeply affects the quality of life (QoL) of affected patients. A combined protocol consisting of lymph node transfer and a reductive method have never been reported for the treatment of this condition, except for small case series with brief follow-up periods. Methods: This retrospective study analyzed data of 29 patients, mean age 51 ± 17.1 years, who had been diagnosed with bilateral lower extremity lymphedema. Gastroepiploic vascularized lymph node transfer was performed in all the patients, and an excisional procedure was associated according to the clinical stage. Clinical history, circumferential limb measurements, complications, episodes of cellulitis, and responses to the Lymphedema Quality of Life Questionnaire were analyzed. Results: The mean follow-up was 38.4 ± 11.8 months. A significant reduction in the episodes of cellulitis per year was observed (p < 0.001). In our series, BMI and duration of symptoms were significantly related to the development of cellulitis during the postoperative period, p = 0.006 and p = 0.020, respectively. The LYMQoL questionnaire showed a significant quality of life improvement from 3.4 ± 0.9 to 6.2 ± 0.8 (p < 0.05). Conclusions: An integrated approach is essential for the treatment of bilateral lower extremity lymphedema: reductive and reconstructive methods are complementary to achieve a successful outcome. Timely treatment and BMI reduction are relevant in order to decrease the number of episodes of cellulitis. An attentive follow-up is necessary to identify recurrence and treat affected patients in time.

The Boston lymphatic center's early experience with lymph node transplantation to the upper extremity

Aim

Although vascularized lymph node transplantation (VLNT) has gained recognition as an effective treatment option for lymphedema, no consensus on the timing of transplant with other lymphatic procedures has been established. The aim of this study is to describe our institutional experience with VLNT, including our staged approach and report postoperative outcomes.

Methods

A retrospective review of patients who underwent VLNT for upper extremity lymphedema from May 2017 to April 2022 was conducted. Patients were divided into fat- or fluid-dominant phenotypes based on preoperative workup. Patients with a minimum of 12-month follow-up were included. Records were reviewed for demographic, intraoperative, and surveillance data.

Results

Twenty-three patients underwent VLNT of the upper extremity during the study period, of which eighteen met the study criteria. Nine patients had fluid-dominant disease and nine patients had fat-dominant disease and had undergone prior debulking at our institution. Fluid-dominant patients demonstrated slight reductions in limb volume and hours in compression, and improvement in quality-of-life scores at twelve months. Fat-dominant patients who underwent prior debulking had a slight increase in limb volume without a change in hours of compression, and demonstrated improvements in quality-of-life scores in nearly all subdomains. Overall, 17% of patients discontinued compression therapy entirely. Improvement in extremity edema was present in 83% of postoperative MRIs.

Conclusion

VLNT had varying effects on limb measurements while reliably improving quality-of-life and allowing for the potential of discontinuing compression. Utilizing a staged approach wherein debulking is performed upfront may be particularly beneficial for patients with fat-dominant disease.

Crosstalk Between Adipose and Lymphatics in Health and Disease

Adipose tissue, once thought to be an inert receptacle for energy storage, is now recognized as a complex tissue with multiple resident cell populations that actively collaborate in response to diverse local and systemic metabolic, thermal, and inflammatory signals. A key participant in adipose tissue homeostasis that has only recently captured broad scientific attention is the lymphatic vasculature. The lymphatic system's role in lipid trafficking and mediating inflammation makes it a natural partner in regulating adipose tissue, and evidence supporting a bidirectional relationship between lymphatics and adipose tissue has accumulated in recent years. Obesity is now understood to impair lymphatic function, whereas altered lymphatic function results in aberrant adipose tissue deposition, though the molecular mechanisms governing these phenomena have yet to be fully elucidated. We will review our current understanding of the relationship between adipose tissue and the lymphatic system here, focusing on known mechanisms of lymphatic-adipose crosstalk.

Stewart-Treves Syndrome in Obesity-Associated Chronic Lymphedema: A Case Report

Stewart-Treves syndrome (STS) is defined as the development of cutaneous angiosarcoma in the presence of long-standing lymphedema and is a rare disease with only about 400 cases reported in world literature. We report a case of a 63-year-old morbidly obese woman with a long-standing history of lymphedema who developed angiosarcoma of the right lower extremity with metastasis and presented with acute respiratory distress. The patient underwent a thorough laboratory workup with a chest X-ray showing bilateral effusions. The hematology-oncology service was consulted and found the patient to have significant progression of angiosarcoma causing respiratory failure and cardiac instability. A decision to transition to hospice care was made and the patient eventually passed away in the intensive care unit. We present this case to raise awareness of STS in medical literature to understand its clinical manifestations better. Early detection is imperative as angiosarcoma is commonly an aggressive disease.

Effect of Postoperative Compression Therapy on the Success of Liposuction in Patients with Advanced Lower Limb Lymphedema

Objective: There is limited information on postoperative care after liposuction for lymphedema limb. The aim of this retrospective study was to identify the threshold compression pressure and other factors that lead liposuction for lower limb lymphedema to success. Materials and Methods: Patients were divided according to whether they underwent compression therapy with both stockings and bandaging (SB group), stockings alone (S group), or bandaging alone (B group) for 6 months after liposuction. The postoperative compression pressure and rate of improvement were compared according to the postoperative compression method. We also investigated whether it was possible to decrease the compression pressure after 6 months. Liposuction was considered successful if improvement rate was >15. Results: Mean compression pressure was significantly lower in the S group than in the SB group or B group. The liposuction success rate was significantly higher in the SB group than in the B group or S group. There was not a significant difference between the values at 6 months after liposuction and at 6 months after a decrease in compression pressure in the successful group. Conclusion: Our results suggest that stable high-pressure postoperative compression therapy is key to the success of liposuction for lower limb lymphedema and is best achieved by using both stockings and bandages. The postoperative compression pressure required for liposuction to be successful was >40 mmHg on the lower leg and >20 mmHg on the thigh. These pressures could be decreased after 6 months.

Development and physiological functions of the lymphatic system: insights from human genetic studies of primary lymphedema

Primary lymphedema is a long-term (chronic) condition characterized by tissue lymph retention and swelling that can affect any part of the body, although it usually develops in the arms or legs. Due to the relevant contribution of the lymphatic system to human physiology, while this review mainly focuses on the clinical and physiological aspects related to the regulation of fluid homeostasis and edema, clinicians need to know that the impact of lymphatic dysfunction with a genetic origin can be wide ranging. Lymphatic dysfunction can affect immune function so leading to infection; it can influence cancer development and spread, and it can determine fat transport so impacting on nutrition and obesity. Genetic studies and the development of imaging techniques for the assessment of lymphatic function have enabled the recognition of primary lymphedema as a heterogenic condition in terms of genetic causes and disease mechanisms. In this review, the known biological functions of several genes crucial to the development and function of the lymphatic system are used as a basis for understanding normal lymphatic biology. The disease conditions originating from mutations in these genes are discussed together with a detailed clinical description of the phenotype and the up-to-date knowledge in terms of disease mechanisms acquired from in vitro and in vivo research models.

Non-contrast magnetic resonance lymphography (NCMRL) in cancer-related secondary lymphedema: acquisition technique and imaging findings

Cancer-related secondary lymphedema (LE) is a widespread issue, which markedly affects patients' quality of life. Its diagnosis is mainly clinical since there is no consensus on the best imaging technique that should be used to assess this pathology. Even if lymphedema treatment has been traditionally conservative and mainly based on compressive bandages and decongestive therapy, new surgical techniques are proving their effectiveness in the management of the disease and made proper assessment and characterization of lymphedema necessary. In this scenario, non-contrast magnetic resonance lymphography (NCMRL) is acquiring an increasing role, as a non-invasive imaging technique, useful for the analysis of LE. NCMRL is an effective tool in diagnosis confirmation, in providing information about the structural changes of the affected limbs, in grading this disorder, and provides a guide for LE management and treatment planning. This article aims to provide an overview of the literature regarding this examination, analyzing the acquisition technique, the interpretation of the imaging findings and their usefulness, the advantages and limits of this technique, to help the radiologist approach this relatively new investigation in cases of cancer-related LE.

Adipocytes are larger in lymphedematous extremities than in controls

Lymphedema is caused by dysfunctional lymph vessels or as a complication of cancer treatment leading to edema and adipose tissue deposition. One hypothesis is that adipocyte hypertrophy contributes to the volume increase in lymphedema. The aim of the study was to compare adipocyte size in arm and leg lymphedema and controls. The adipocyte size difference was also compared between the arms and legs. Furthermore, any link between adipocyte size difference and gender, lymphedema onset, duration, previous radio- and chemotherapy was studied, as well as any relationship to total excess volume increase in the extremities, body mass index (BMI) and body weight. Adipose tissue biopsies from the lymphedematous and non-affected extremities were taken from 47 patients. The adipocytes sizes were measured using an Olympus PROVIS microscope, Olympus DP50 camera (Olympus, Tokyo, Japan) and ImageJ program (NIH, Bethesda, MD). Additional information was obtained from the Lymphedema Center database. The data were assembled in Excel and statistics was calculated in SPSS^® Statistics 23 (IBM^®, Armonk, NY). The adipocyte size (mean ± SEM) in the lymphedematous extremities was significantly larger, 8880 ± 291 μm², compared to the adipocyte size in the non-affected extremities, where it was 7143 ± 280 μm², i.e. 24% larger (p < .001). The adipocyte size increase was larger in arm than in leg lymphedema. No correlation was found between adipocyte size and gender or onset. However, a negative correlation was found between adipocyte size difference and duration. No correlation was found between adipocyte size and previous chemo- or radiotherapy. There was a positive correlation between adipocyte size and BMI. Hypertrophy of adipocytes was seen in the lymphedematous extremities versus control and contributes to the excess volume.

Foxo1 deletion promotes the growth of new lymphatic valves

Patients with congenital lymphedema suffer from tissue swelling in part due to mutations in genes regulating lymphatic valve development. Lymphatic valve leaflets grow and are maintained throughout life in response to oscillatory shear stress (OSS), which regulates gene transcription in lymphatic endothelial cells (LECs). Here, we identified the first transcription factor, Foxo1, that repressed lymphatic valve formation by inhibiting the expression of valve-forming genes. We showed that both embryonic and postnatal ablation of Foxo1 in LECs induced additional valve formation in postnatal and adult mice in multiple tissues. Our quantitative analyses revealed that after deletion, the total number of valves in the mesentery was significantly (P < 0.01) increased in the Foxo1LEC-KO mice compared with Foxo1fl/fl controls. In addition, our quantitative real-time PCR (RT-PCR) data from cultured LECs showed that many valve-forming genes were significantly (P < 0.01) upregulated upon knockdown of FOXO1. To confirm our findings in vivo, rescue experiments showed that Foxc2+/- mice, a model of lymphedema-distichiasis, had 50% fewer lymphatic valves and that the remaining valves exhibited backleak. Both valve number and function were completely restored to control levels upon Foxo1 deletion. These findings established FOXO1 as a clinically relevant target to stimulate de novo lymphatic valve formation and rescue defective valves in congenital lymphedema.

A Rare Cause of Exudative Pleural Effusion in a Female

Yellow nail syndrome is an extremely rare syndrome that presents with a clinical triad of thickened yellow nails, lymphedema, and recurring pulmonary manifestations (pleural effusion, chronic cough, or bronchiectasis), usually in the population above the age of 50 years. We describe a case of yellow nail syndrome in a 48-year-old lady who presented with the typical classical triad of this syndrome.

Advances in Lymphedema

Lymphedema is a common, complex, and inexplicably underappreciated human disease. Despite a history of relative neglect by health care providers and by governmental health care agencies, the last decade has seen an explosive growth of insights into, and approaches to, the problem of human lymphedema. The current review highlights the significant advances that have occurred in the investigative and clinical approaches to lymphedema, particularly over the last decade. This review summarizes the progress that has been attained in the realms of genetics, lymphatic imaging, and lymphatic surgery. Newer molecular insights are explored, along with their relationship to future molecular therapeutics. Growing insights into the relationships among lymphedema, obesity, and other comorbidities are important to consider in current and future responses to patients with lymphedema.