Platelet factor 4 is a biomarker for lymphatic-promoted disorders

Lipedema: A Disease Triggered by M2 Polarized Macrophages?

Background/Objectives: Lipedema is a progressive disease that results in the bilateral and symmetrical accumulation of subcutaneous fat in the legs and/or arms, affecting almost exclusively women. Methods: A comprehensive review of the peer-reviewed literature was conducted between November 2024 and February 2025. Results: The pathophysiology of lipedema is complex and, especially in the early stages, shows similarities to obesity, involving adipocytes, adipose tissue-resident macrophages, and endothelial cells. In lipedema, systemic levels and the adipocyte expression of the classical adipokines adiponectin and leptin appear normal, while it remains unclear if markers of inflammation and oxidative stress are increased. Macrophages in the adipose tissue of patients have an anti-inflammatory M2 phenotype and express high levels of the scavenger receptor CD163. These cells affect adipogenesis and seem to have a central role in adipose tissue accumulation. Increased lymphatic and blood vessel permeability are comorbidities of lipedema that occur in early disease states and may contribute to disease progression. Conclusions: This review summarizes our current understanding of the pathophysiology of lipedema with a focus on the role of stromal vascular localized M2 macrophages.

Brazilian Consensus Statement on Lipedema using the Delphi methodology

Lipedema, historically underrecognized, has recently gained attention due to advancements in research and growing public awareness. The Brazilian Consensus Statement on Lipedema, developed by the Brazilian Society of Angiology and Vascular Surgery, aims to establish clear recommendations for the diagnosis, treatment, and management of lipedema. Using the Delphi methodology, experts elaborated 90 statements about lipedema, which were then evaluated by a panel of 113 professionals. The statements were analyzed using SurveyMonkey, with a 75% agreement threshold required for their inclusion in the consensus statement. Most statements achieved significant consensus, with only 9 topics requiring further investigation. This consensus statement highlights the complexity of lipedema, the effectiveness of conservative treatment over surgery, the need for multidisciplinary approaches, and the importance of awareness to reduce underdiagnosis and stigma. It also underscores the ongoing need for research to develop more effective management strategies.

Building evidence for diagnosis of lipedema: using a classification and regression tree (CART) algorithm to differentiate lipedema from lymphedema patients

BACKGROUND

Discriminating lipedema from lymphedema becomes challenging in the absence of a pathognomonic test. The objective was to find the best manifestations that discriminate between lipedema and lymphedema and to build a diagnosis algorithm.

METHODS

Prospective cohort study of two cohorts of patients, one with lipedema and another with lymphedema. Inclusion criteria for lipedema cohort involved bilateral lower limbs (LL) enlargement and at least three symptoms: pain/tenderness, bruising, familial history, no Stemmer's sign, symmetrical involvement, and non-swollen feet. The lymphedema cohort included female patients with LL lymphedema. A univariate analysis was performed to determine which clinical features were different between both samples. We used a TREE procedure to create a tree-based classification model using the CART (Classification And Regression Tree) algorithm, in order to discriminate lipedema from lymphedema patients.

RESULTS

Currently, 138 lipedema and 111 lymphedema patients were included. After univariate analysis, symmetrical involvement, disproportion between upper and lower parts of the body, spare feet, bruising, spider veins, family history, and pain were significantly more present in lipedema than in lymphedema (P<0.0001). Stemmer's sign, lymphangitis bouts, pitting and fibrosis were more representative of lymphedema (P<0.0001). The most important variables for discrimination were: disproportion (100%), spare feet (92.6%), bruising (92.3%) and symmetrical involvement (90.3%). After CART analysis, only three variables were retained in the final model: bruising, disproportion and spare feet. The model's accuracy was 100% with a probability error of 0.0% (SE: 0.00).

CONCLUSIONS

A simple clinical tree can be used to classify patients between lymphedema and lipedema.

Identification of Specific microRNAs in Adipose Tissue Affected by Lipedema

Lipedema is a chronic disorder affecting women with a 10% incidence worldwide. It is often confused with obesity. This study was undertaken to study microRNAs in lipedema tissue assessed by direct hybridization using the robust n-counter flex DX CE-IVD platform. The mean age of the subjects participating in the study was 40.29 (±12.17). The mean body weight and BMI were 67.37 (±10.02) and 25.75 (±4.10), respectively. The lipedema stages included were I and II. The differential expressed human (hsa)-miRNAs were determined according to a log2 fold-change (LFC) of 0.5 and p value < 0.05. To these, increased expression of hsa-let-7g-5p was evident, as well as reduced levels of hsa-miR-371a-5p, -4454+7975, -365a+b-3p, -205-5p, -196a-5p, -4488, -2116-5p, -141-3p, -208a-3p, -302b-3p, 374a-5p, and -1297. Then, several bioinformatics tools were used to analyze microarray data focusing on validated target genes in silico. KEGG and Gene Ontology (GO) pathway enrichment analysis was conducted. Furthermore, the protein-protein interaction and co-expression network were analyzed using STRING and Cytoscape, respectively. The most upregulated miRNA mainly affected genes related to cell cycle, oocyte meiosis, and inflammatory bowel disease. The downregulated microRNAs were related to endocrine resistance, insulin resistance, hypersensitivity to AGE-RAGEs, and focal adhesion. Finally, we validated by RT-PCR the upregulated hsa-let-7g-5p and two down-regulated ones, hsa-miR-205-5p and hsa-miR-302b-3p, confirming microarray results. In addition, three mRNA target miRNAs were monitored, SMAD2, the target of the hsa-let-7g-5p, and ESR1 and VEGFA, the target of hsa-miR-205-5p and hsa-miR-302b-3p, respectively. Our results open a new direction for comprehending biochemical mechanisms related with the pathogenesis of lipedema, shedding light on this intricate pathophysiological condition that could bring to light possible biomarkers in the future.

A Divergent Platelet Transcriptome in Patients with Lipedema and Lymphedema

Lipedema and lymphedema are physically similar yet distinct diseases that are commonly misdiagnosed. We previously reported that lipedema and lymphedema are associated with increased risk for venous thromboembolism (VTE). The underlying etiology of the prothrombotic profile observed in lipedema and lymphedema is unclear, but may be related to alterations in platelets. Our objective was to analyze the platelet transcriptome to identify biological pathways that may provide insight into platelet activation and thrombosis. The platelet transcriptome was evaluated in patients with lymphedema and lipedema, then compared to control subjects with obesity. Patients with lipedema were found to have a divergent transcriptome from patients with lymphedema. The platelet transcriptome and impacted biological pathways in lipedema were surprisingly similar to weight-matched comparators, yet different when compared to overweight individuals with a lower body mass index (BMI). Differences in the platelet transcriptome for patients with lipedema and lymphedema were found in biological pathways required for protein synthesis and degradation, as well as metabolism. Key differences in the platelet transcriptome for patients with lipedema compared to BMI-matched subjects involved metabolism and glycosaminoglycan processing. These inherent differences in the platelet transcriptome warrant further investigation, and may contribute to the increased risk of thrombosis in patients with lipedema and lymphedema.

Proposed Framework for Research Case Definitions of Lipedema

Background: Our aim is to propose a framework for the development of a research case definition of lipedema, based on current available literature and those observations that can be applied to future lipedema research with the intent to standardize and strengthen the scientific evidence base. Methods and Results: We conducted a narrative review of the literature, and identified consensus characteristics and disputed characteristics that could be included in a research case definition of lipedema. After considering the strength of the evidence and how each characteristic might be measured in a research study, we recommended an approach for the development of a research case definition of lipedema that would be based on consideration of five agreed-upon characteristics, and five disputed, or less substantiated, characteristics as additional evidence to enhance specificity. Conclusions: We present a case definition framework for lipedema drawn from the scientific literature that can be applied to future studies on lipedema. Utilizing this framework should help to increase the sensitivity and specificity of case definition and provide an opportunity for meta-analysis of clinical studies and facilitate future research intercomparisons.

Ketogenic Diet: A Nutritional Therapeutic Tool for Lipedema?

PURPOSE OF REVIEW

This review aims to provide an overview of the current evidence on the efficacy, also considering the anti-inflammatory properties and safety of very low-calorie ketogenic diet (VLCKD) as a potential treatment for lipedema, particularly in the context of obesity.

RECENT FINDINGS

Lipedema is a chronic disease characterized by abnormal and painful fat buildup on the legs and/or arms. It is often misdiagnosed as obesity or lymphedema. However, although lipedema and obesity can coexist, unlike obesity, lipedema usually affects the legs and thighs without affecting the feet or hands, and the abnormal deposition of adipose tissue in lipedema is painful. The current lifestyle interventions are often unsuccessful in the management of lipedema. There is no consensus on the most effective nutritional approach for managing lipedema. Recent studies have suggested that VLCKD may be an effective treatment for lipedema, demonstrating that it is also superior to other nutritional approaches such as Mediterranean diet or intermittent fasting. Lipedema is a chronic and debilitating disease characterized by abnormal and painful accumulation of adipose tissue in the legs. VLCKD has been shown to be an effective treatment for lipedema, especially in the context of obesity, due to its anti-inflammatory properties. However, further research is needed to determine the long-term safety and efficacy of VLCKD as a treatment for lipedema.

[Searching for Evidence: A Systematic Review of the Pathology of Lipoedema]

BACKGROUND

Lipoedema is a symmetrically localised, painful hypertrophy of subcutaneous adipose tissue in the extremities with marked disproportion to the trunk, and almost exclusively affects females. Despite being first described over 80 years ago, the aetiology and pathogenesis of the disease are largely unknown and are currently the subject of intensive research efforts.

METHODS

To summarise the current evidence-based literature on the cellular pathologies and aetiology of lipoedema, a PRISMA-based systematic review was conducted within the National Library of Medicine and Cochrane databases.

RESULTS

A total of 53 studies were identified and included in this review. The results were classified and summarised into categories.

CONCLUSION

Although there has been a significant increase in research activity and recent publication of extensive studies with a histological and molecular genetic focus, the fundamental aetiology and pathology of lipoedema remains largely unclear. The current data shows discrepancies across studies, particularly with regard to the "oedematous" component of lipoedema. The frequently present comorbidities "lymphoedema" and "obesity", primarily in advanced stages of lipoedema, complicate the diagnostic differentiation and clear definition of study cohorts in scientific research.

Lipedema: The Use of Cultured Adipocytes for Identification of Diagnostic Markers

BACKGROUND

Lipedema, diagnosed most often in women, is a progressive disease characterized by the disproportionate and symmetrical distribution of adipose tissue, primarily in the extremities. Although numerous results from in vitro and in vivo studies have been published, many questions regarding the pathology and genetic background of lipedema remain unanswered.

METHODS

In this study, adipose tissue-derived stromal/stem cells were isolated from lipoaspirates derived from nonobese and obese donors with or without lipedema. Growth and morphology, metabolic activity, differentiation potential, and gene expression were evaluated using quantification of lipid accumulation, metabolic activity assay, live-cell imaging, reverse transcription polymerase chain reaction, quantitative polymerase chain reaction, and immunocytochemical staining.

RESULTS

The adipogenic potential of lipedema and nonlipedema adipose tissue-derived stromal/stem cells did not rise in parallel with the donors' body mass index and did not differ significantly between groups. However, in vitro differentiated adipocytes from nonobese lipedema donors showed significant upregulation of adipogenic gene expression compared with nonobese controls. All other genes tested were expressed equally in lipedema and nonlipedema adipocytes. The adiponectin/leptin ratio was significantly reduced in adipocytes from obese lipedema donors compared with their nonobese lipedema counterparts. Increased stress fiber-integrated smooth muscle actin was visible in lipedema adipocytes compared with nonlipedema controls and appeared enhanced in adipocytes from obese lipedema donors.

CONCLUSIONS

Not only lipedema per se but also body mass index of donors affect adipogenic gene expression substantially in vitro. The significantly reduced adiponectin/leptin ratio and the increased occurrence of myofibroblast-like cells in obese lipedema adipocyte cultures underscores the importance of attention to the co-occurrence of lipedema and obesity. These are important findings toward accurate diagnosis of lipedema.

CLINICAL RELEVANCE STATEMENT

Our study highlights not only the difficulty in lipedema diagnostics but also the tremendous need for further studies on lipedema tissue. Although lipedema might seem to be an underestimated field in plastic and reconstructive surgery, the power it holds to provide better treatment to future patients can not be promoted enough.

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.

A narrative review: CXC chemokines influence immune surveillance in obesity and obesity-related diseases: Type 2 diabetes and nonalcoholic fatty liver disease

Adipose tissue develops lipids, aberrant adipokines, chemokines, and pro-inflammatory cytokines as a consequence of the low-grade systemic inflammation that characterizes obesity. This low-grade systemic inflammation can lead to insulin resistance (IR) and metabolic complications, such as type 2 diabetes (T2D) and nonalcoholic fatty liver disease (NAFLD). Although the CXC chemokines consists of numerous regulators of inflammation, cellular function, and cellular migration, it is still unknown that how CXC chemokines and chemokine receptors contribute to the development of metabolic diseases (such as T2D and NAFLD) during obesity. In light of recent research, the objective of this review is to provide an update on the linkage between the CXC chemokine, obesity, and obesity-related metabolic diseases (T2D and NAFLD). We explore the differential migratory and immunomodulatory potential of CXC chemokines and their mechanisms of action to better understand their role in clinical and laboratory contexts. Besides that, because CXC chemokine profiling is strongly linked to leukocyte recruitment, macrophage recruitment, and immunomodulatory potential, we hypothesize that it could be used to predict the therapeutic potential for obesity and obesity-related diseases (T2D and NAFLD).

Subcutaneous Adipose Tissue Edema in Lipedema Revealed by Noninvasive 3T MR Lymphangiography

BACKGROUND

Lipedema exhibits excessive lower-extremity subcutaneous adipose tissue (SAT) deposition, which is frequently misidentified as obesity until lymphedema presents. MR lymphangiography may have relevance to distinguish lipedema from obesity or lymphedema.

HYPOTHESIS

Hyperintensity profiles on 3T MR lymphangiography can identify distinct features consistent with SAT edema in participants with lipedema.

STUDY TYPE

Prospective cross-sectional study.

SUBJECTS

Participants (48 females, matched for age [mean = 44.8 years]) with lipedema (n = 14), lipedema with lymphedema (LWL, n = 12), cancer treatment-related lymphedema (lymphedema, n = 8), and controls without these conditions (n = 14).

FIELD STRENGTH/SEQUENCE

3T MR lymphangiography (nontracer 3D turbo-spin-echo).

ASSESSMENT

Review of lymphangiograms in lower extremities by three radiologists was performed independently. Spatial patterns of hyperintense signal within the SAT were scored for extravascular (focal, diffuse, or not apparent) and vascular (linear, dilated, or not apparent) image features.

STATISTICAL TESTS

Interreader reliability was computed using Fleiss Kappa. Fisher's exact test was used to evaluate the proportion of image features between study groups. Multinomial logistic regression was used to assess the relationship between image features and study groups. The odds ratio (OR) and 95% confidence interval (CI) of SAT extravascular and vascular features was reported in groups compared to lipedema. The threshold of statistical significance was P < 0.05.

RESULTS

Reliable agreement was demonstrated between three independent, blinded reviewers (P < 0.001). The frequency of SAT hyperintensities in participants with lipedema (36% focal, 36% diffuse), LWL (42% focal, 33% diffuse), lymphedema (62% focal, 38% diffuse), and controls (43% focal, 0% diffuse) was significantly distinct. Compared with lipedema, SAT hyperintensities were less frequent in controls (focal: OR = 0.63, CI = 0.11-3.41; diffuse: OR = 0.05, CI = 0.00-1.27), similar in LWL (focal: OR = 1.29, CI = 0.19-8.89; diffuse: OR = 1.05, CI = 0.15-7.61), and more frequent in lymphedema (focal: OR = 9.00, CI = 0.30-274.12; diffuse: OR = 5.73, CI = 0.18-186.84).

DATA CONCLUSION

Noninvasive MR lymphangiography identifies distinct signal patterns indicating SAT edema and lymphatic load in participants with lipedema.

EVIDENCE LEVEL

1 TECHNICAL EFFICACY: Stage 1.

Comparison of Actual and Predicted Resting Metabolic Rate in Women with Lipedema

Background: An adequate dietary energy supply is particularly important in patients with lipedema as it promotes weight and fat loss. Accurate estimation of resting metabolic rate (RMR) allows implementing a proper calorie restriction diet in patients with lipedema. Our study aimed to compare actual resting metabolic rate (aRMR) with predicted resting metabolic rate (pRMR) in women with lipedema and to determine the association between individual body composition parameters, body mass index, and aRMR. Methods and Results: A total of 108 women diagnosed with lipedema were enrolled in the study. aRMR was obtained by indirect calorimetry (IC) using FitMate WM metabolic system (Cosmed, Rome, Italy). pRMR was estimated with predictive equations and bioelectric impedance analysis (BIA). All body composition parameters were based on BIA. The mean aRMR in the study group was 1705.2 ± 320.7 kcal/day. This study found the agreement of predictive equations compared to IC is low (<60%). Most methods of predicted RMR measurement used in our study significantly underpredicted aRMR in patients with lipedema. Therefore, the most applied equations remain useless in clinical practice in this specific population due to large individual differences among the studied women. Conclusions: IC is the best tool to evaluate RMR in evaluated patients with lipedema. It is necessary to propose a new equation to RMR determination in clinical practice.

Lipedema Research-Quo Vadis?

When studying the current literature, one might get the impression that lipedema is a "modern" disease, with increasing incidence and augmenting prevalence throughout Western countries during the last decade. However, a quick look into older textbooks shows that disproportionate accumulation of fat in female bodies has long been known without being recognized as an independent disease. Nevertheless, it was not until 1940 that Allen and Hines described a "syndrome characterized by fat legs and orthostatic edema" in a seminal publication. The mere awareness that people who have lipedema are not just overweight but suffer from a yet poorly defined pathological condition, may be considered a decisive leap forward in the understanding of lipedema. A number of comprehensive publications have since dealt with the clinical presentation of lipedema and have provided the first clues towards the potential pathological mechanisms underlying its initiation and progression. Nevertheless, despite all effort that has been undertaken to unravel lipedema pathology, many questions have remained unanswered. What can be deduced with certainty from all experimental and medical evidence available so far is that lipedema is neither a cosmetic problem nor is it a problem of lifestyle but should be accepted as a serious disease with yet undetermined genetic background, which makes women's lives unbearable from both a physical and psychological point of view. To date, results from clinical inspections have led to the categorization of various types and stages of lipedema, describing how the extremities are affected and evaluating its progression, as demonstrated by skin alterations, adipose tissue volume increase and physical and everyday-behavioral impediments. There is accumulating evidence showing that advanced stages of lipedema are usually accompanied by excessive weight or obesity. Thus, it is not unreasonable to assume that the progression of lipedema is largely driven by weight gain and the pathological alterations associated with it. Similarly, secondary lymphedema is frequently found in lipedema patients at advanced stages. Needless to say, both conditions considerably blur the clinical presentation of lipedema, making diagnosis difficult and scientific research challenging. The present literature review will focus on lipedema research, based on evidence fromex vivo and in vitro data, which has accumulated throughout the last few decades. We will also open the discussion as to whether the currently used categorization of lipedema stages is still sufficient and up-to-date for the accurate description of this enigmatic disease, whose name, strangely enough, does not match its pathologic correlate.

Lipedema: Insights into Morphology, Pathophysiology, and Challenges

Lipedema is an adipofascial disorder that almost exclusively affects women. Lipedema leads to chronic pain, swelling, and other discomforts due to the bilateral and asymmetrical expansion of subcutaneous adipose tissue. Although various distinctive morphological characteristics, such as the hyperproliferation of fat cells, fibrosis, and inflammation, have been characterized in the progression of lipedema, the mechanisms underlying these changes have not yet been fully investigated. In addition, it is challenging to reduce the excessive fat in lipedema patients using conventional weight-loss techniques, such as lifestyle (diet and exercise) changes, bariatric surgery, and pharmacological interventions. Therefore, lipedema patients also go through additional psychosocial distress in the absence of permanent treatment. Research to understand the pathology of lipedema is still in its infancy, but promising markers derived from exosome, cytokine, lipidomic, and metabolomic profiling studies suggest a condition distinct from obesity and lymphedema. Although genetics seems to be a substantial cause of lipedema, due to the small number of patients involved in such studies, the extrapolation of data at a broader scale is challenging. With the current lack of etiology-guided treatments for lipedema, the discovery of new promising biomarkers could provide potential solutions to combat this complex disease. This review aims to address the morphological phenotype of lipedema fat, as well as its unclear pathophysiology, with a primary emphasis on excessive interstitial fluid, extracellular matrix remodeling, and lymphatic and vasculature dysfunction. The potential mechanisms, genetic implications, and proposed biomarkers for lipedema are further discussed in detail. Finally, we mention the challenges related to lipedema and emphasize the prospects of technological interventions to benefit the lipedema community in the future.

The Peripheral Lymphatic System Is Impaired by the Loss of Neuronal Control Associated with Chronic Spinal Cord Injury

Spinal cord injury (SCI) is associated with venous vascular dysfunction below the level of injury, resulting in dysregulation of tissue fluid homeostasis in afflicted skin. The purpose of this study was to determine whether loss of neuronal control in chronic SCI also affects the skin lymphatic system. Morphology of lymphatics was characterized by immunohistochemistry and lymphatic gene expression profiles determined by DNA microarray analysis. In SCI, skin lymphatic function appeared to be impaired, because the ratio of functionally dilated versus collapsed lymphatic vessels was decreased 10-fold compared with control. Consequently, the average lumen area of lymphatic vessels was almost halved, possibly due to the known impaired connective tissue integrity of SCI skin. In fact, collagenases were found to be overexpressed in SCI skin, and dermal collagen structure was impaired. Molecular profiling also suggested an SCI-specific phenotype of increased connective tissue turnover and decreased lymphatic contractility. The total number of lymphatic vessels in SCI skin, however, was doubled, pointing to enhanced lymphangiogenesis. In conclusion, these data show, for the first time, that lymphatic function and development in human skin are under neuronal control. Because peripheral venous and lymphatic vascular defects are associated with disturbed fluid homeostasis, inappropriate wound healing reactions, and impaired skin immunity, they might contribute to the predisposition of afflicted individuals to pressure ulcer formation and wound healing disorders.

Lymphatic function and anatomy in early stages of lipedema

OBJECTIVE

Lipedema is an inflammatory subcutaneous adipose tissue disease that develops in women and may progress to lipolymphedema, a condition similar to lymphedema, in which lymphatic dysfunction results in irresolvable edema. Because it has been shown that dilated lymphatic vessels, impaired pumping, and dermal backflow are associated with presymptomatic, cancer-acquired lymphedema, this study sought to understand whether these abnormal lymphatic characteristics also characterize early stages of lipedema prior to lipolymphedema development.

METHODS

In a pilot study of 20 individuals with Stage I or II lipedema who had not progressed to lipolymphedema, lymphatic vessel anatomy and function in upper and lower extremities were assessed by near-infrared fluorescence lymphatic imaging and compared with that of a control population of similar age and BMI.

RESULTS

These studies showed that, although lower extremity lymphatic vessels were dilated and showed intravascular pooling, the propulsion rates significantly exceeded those of control individuals. Upper extremity lymphatics of individuals with lipedema were unremarkable. In contrast to individuals with lymphedema, individuals with Stage I and II lipedema did not exhibit dermal backflow.

CONCLUSIONS

These results suggest that, despite the confusion in the diagnoses between lymphedema and lipedema, their etiologies differ, with lipedema associated with lymphatic vessel dilation but not lymphatic dysfunction.

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.

Exploring disease interrelationships in patients with lymphatic disorders: A single center retrospective experience

BACKGROUND

The lymphatic contribution to the circulation is of paramount importance in regulating fluid homeostasis, immune cell trafficking/activation and lipid metabolism. In comparison to the blood vasculature, the impact of the lymphatics has been underappreciated, both in health and disease, likely due to a less well-delineated anatomy and function. Emerging data suggest that lymphatic dysfunction can be pivotal in the initiation and development of a variety of diseases across broad organ systems. Understanding the clinical associations between lymphatic dysfunction and non-lymphatic morbidity provides valuable evidence for future investigations and may foster the discovery of novel biomarkers and therapies.

METHODS

We retrospectively analysed the electronic medical records of 724 patients referred to the Stanford Center for Lymphatic and Venous Disorders. Patients with an established lymphatic diagnosis were assigned to groups of secondary lymphoedema, lipoedema or primary lymphovascular disease. Individuals found to have no lymphatic disorder were served as the non-lymphatic controls. The prevalence of comorbid conditions was enumerated. Pairwise co-occurrence pattern analyses, validated by Jaccard similarity tests, was utilised to investigate disease-disease interrelationships.

RESULTS

Comorbidity analyses underscored the expected relationship between the presence of secondary lymphoedema and those diseases that damage the lymphatics. Cardiovascular conditions were common in all lymphatic subgroups. Additionally, statistically significant alteration of disease-disease interrelationships was noted in all three lymphatic categories when compared to the control population.

CONCLUSIONS

The presence or absence of a lymphatic disease significantly influences disease interrelationships in the study cohorts. As a physiologic substrate, the lymphatic circulation may be an underappreciated participant in disease pathogenesis. These relationships warrant further, prospective scrutiny and study.

Body Composition Assessment by Dual-Energy X-Ray Absorptiometry: A Useful Tool for the Diagnosis of Lipedema

INTRODUCTION

Lipedema is a poorly known condition. Diagnosis is based almost exclusively on clinical criteria, which may be subjective and not always reliable. This study aimed to investigate regional body composition (BC) by dual-energy X-ray absorptiometry (DXA) in patients with lipedema and healthy controls and to determine cut-off values of fat mass (FM) indices to provide an additional tool for the diagnosis and staging of this condition.

METHODS

This study is a single-center case-control study performed at Lausanne University Hospital, Switzerland. Women with clinically diagnosed lipedema underwent regional BC assessment by DXA. The control group without clinical lipedema was matched for age and body mass index (BMI) at a ratio of 1:2 and underwent similar examination. Regional FM (legs, arms, legs and arms, trunk, android and gynoid FM) was measured in (kg) and divided by FM index (FMI) (kg/m2) and total FM (kg). The trunk/legs and android/gynoid ratios were calculated. For all indices of FM distribution showing a significant difference between cases and controls, we defined the receiver operating characteristic (ROC) curves, calculating the area under the curve (AUC), sensitivity, specificity, and Youden's index. Types and stages of lipedema were compared in terms of FM indices. Correlation analyses between all FM distribution indices and lipedema stages were performed.

RESULTS

We included 222 women (74 with lipedema and 148 controls). Overall, the mean age was 41 years (standard deviation [SD] 11), and mean BMI was 30.9 kg/m2 (SD 7.6). A statistically significant difference was observed for all DXA-derived indices of FM distribution between groups, except for arm FM indices. The ROC curve analysis of leg FM/total FM, as a potential indicator of lipedema, resulted in an AUC of 0.90 (95% confidence interval 0.86-0.94). According to Youden's index, optimal cut-off value identifying lipedema was 0.384. Sensitivity and specificity were 0.95 and 0.73, respectively. We found no significant differences between lipedema types and stages in terms of FM indices, nor significant correlations between the latter and lipedema stages.

DISCUSSION/CONCLUSION

BC assessment by DXA, and particularly calculation of the leg FM/total FM index, is a simple tool that may help clinicians rule out lipedema in doubtful cases.

Lipedema Can Be Treated Non-Surgically: A Report of 5 Cases

BACKGROUND Lipedema is a chronic progressive disease characterized by the abnormal accumulation of fat in the subcutaneous region. Both medical and surgical treatments have been described in international guidelines; however, the current literature is biased toward promoting liposuction as the primary treatment of lipedema, and this can lead to the misapprehension that liposuction is the only form of definitive treatment. CASE REPORT In the present study, we report 5 cases at various stages of the evolution of lipedema, all with different therapeutic objectives. Case 1 reported having persistent bruising and pain, case 2 reported pain and fat deposition, case 3 reported night cramps and discomfort, case 4 reported leg thickening, and case 5 reported redness in the legs. All of were diagnosed with lipedema in different evolution stages. Our purpose was to demonstrate the possibility of non-surgical therapy, as well as to improve signs and symptoms of lipedema, using the QuASiL questionnaire and measuring changes in volumes and proportions. Good aesthetic outcomes improve both social and psychological status. CONCLUSIONS Currently, there are many described therapies available for lipedema. Liposuction surgery for lipedema should be considered one possible tool. Treatment objectives can be different for each patient. It is imperative to understand each patient's needs in order to offer the best therapy attainable that meets patient requirements and induces a better quality of life. Non-surgical treatment of lipedema is feasible in selected cases, and it can meet the criteria for achieving selected clinical objectives.

Comorbidity and Lymphatic Disease: The Lymphatic Continuum Re-Examined

It has now been ∼20 years since the original Lymphatic Continuum conference was convened, and this continuum has transitioned from a compelling concept to a reality. The explosive growth in our comprehension of lymphatic genetics, development, and function has expanded and modified our traditional views regarding what is, and is not, lymphatic disease. Groundbreaking investigations over the past decade have now defined a large and growing list of pathological conditions in which morphological or function lymphatic alterations can be identified. This list includes atherosclerosis and dyslipidemia, hypertension and other cardiovascular diseases, inflammation and inflammatory bowel disease, obesity, narrow angle glaucoma, and, most recently and compellingly, neurodegenerative disease. The sometimes overlapping but largely disparate nature of these various aforementioned disease categories suggests that the presence, or absence, of structural or functional lymphatic derangements may represent a previously unrecognized unifying influence in the maintenance of health and the promotion of disease. Future investigation of lymphatic mechanisms in disease will likely continue to elucidate the influences of lymphatic dysfunction, perhaps subtle, that can invest other, seemingly unrelated, diseases. In future, such discoveries will provide mechanistic insights and may potentiate the development of a new lymphatic-based approach to human disease diagnosis and therapeutics.

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.

Standard of care for lipedema in the United States

Background

Lipedema is a loose connective tissue disease predominantly in women identified by increased nodular and fibrotic adipose tissue on the buttocks, hips and limbs that develops at times of hormone, weight and shape change including puberty, pregnancy, and menopause. Lipedema tissue may be very painful and can severely impair mobility. Non-lipedema obesity, lymphedema, venous disease, and hypermobile joints are comorbidities. Lipedema tissue is difficult to reduce by diet, exercise, or bariatric surgery.

Methods

This paper is a consensus guideline on lipedema written by a US committee following the Delphi Method. Consensus statements are rated for strength using the GRADE system.

Results

Eighty-five consensus statements outline lipedema pathophysiology, and medical, surgical, vascular, and other therapeutic recommendations. Future research topics are suggested.

Conclusion

These guidelines improve the understanding of the loose connective tissue disease, lipedema, to advance our understanding towards early diagnosis, treatments, and ultimately a cure for affected individuals.

Update in the management of lipedema

Lipedema is a chronic feminine disease that causes abnormal fat deposition in lower limbs and occasionally upper limbs. Easy bruising and pain are common. Lipedema patients suffer from both physical and psychological disability. Despite the relatively high prevalence and the impact on the quality of life, little is known about the disease. The majority of patients are misdiagnosed as lymphedema or obesity. The objective was to perform a non-systematic review on lipedema literature, related to diagnosis and therapy. Regarding pathophysiology, alterations are not exclusively confined to adipose tissue. Lymphatic dysfunction, cardiovascular variations, blood capillary fragility and increased permeability are common. Patients often present with neurological alterations and hormonal malfunction. Elevated cutaneous sodium has been documented. Due to the absence of a defined etiology, evidence-based research is difficult in the management of lipedema. The setting of realistic expectations is important for both patient and medical care provider. The major aims of the management are multimodal for improvements in the quality of life; reduction in heaviness and pain, reshaping the affected limbs, weight control, improvements in mobility. Compression garments, physical therapy, exercise regimens, diet and psychological counseling are necessities. For selected patients, surgical treatment is an added option.

Ultrasound criteria for lipedema diagnosis

BACKGROUND

Lipedema is characterized by the deposition of abnormal fat in the lower and upper limbs bilaterally. It is a disease with high prevalence and genetic characteristics. Non-specific and non-quantified increases in the thickness of the subcutaneous tissue have previously been demonstrated using magnetic resonance imaging and computed tomography.

OBJECTIVES

To evaluate the thickness of the dermis and subcutaneous tissue in predetermined areas as a distinguishing feature between individuals with and without lipedema using ultrasound.

METHODS

Ultrasound images of 89 female patients were analyzed, including patients undergoing clinical investigation for venous insufficiency or lipedema who underwent ultrasound evaluations at our institution. Patients were divided in two groups: with lipedema clinically diagnosed and those without lipedema. They underwent a common Doppler protocol for venous mapping to assess venous insufficiency associated with the evaluation of dermis and subcutaneous thickness at pre-defined points of the lower limbs.

RESULTS

There were 63 patients with lipedema. Anterior thigh, pre-tibial and lateral aspect of the leg and supra-just medial malleolar region were significantly different. Supra-just medial malleolar region was significantly different with BMI above 25. An optimal cutoff value was calculated for the ultrasound diagnosis of lipedema using thickness of the dermis and subcutaneous tissues.

CONCLUSIONS

Studied criteria allow use of simple and reproducible ultrasound cutoff values to diagnose lipedema in the lower limbs. Pre-tibial region thickness measurement, followed by thigh and lateral leg thickness are recommended for the ultrasound diagnosis of lipedema.

Development of a questionnaire and screening model for lipedema

Background

Lipedema is greatly underdiagnosed and there is a lack of low-cost tools to facilitate diagnostic. We created a lipedema screening questionnaire based on a questionnaire for assessing symptoms.

Objectives

The study objectives were to identify relevant clinical questions, develop a screening questionnaire, and construct a model for predicting lipedema.

Method

A simplified questionnaire was constructed and administered to a sample of patients with and without lipedema and then the probability of correct diagnosis was analyzed.

Results

All 109 patients who answered the questionnaire were female and all of them understood the questions. A predictive model using individual question scores achieved an excellent probability of correct diagnosis, at 91.2%, and a predictive model based on total score also achieved a good probability of correct diagnosis, at 86.15%.

Conclusions

The lipedema screening questionnaire is a practical instrument that is quick and easy to administer and can be used with our population for identification of possible lipedema patients, raising the level of suspicion when taking a patient’s history and conducting a physical examination.

Ketogenic diet as a potential intervention for lipedema

Lipedema (LI) is a common yet misdiagnosed condition, often misconstrued with obesity. LI affects women almost exclusively, and its painful and life-changing symptoms have long been thought to be resistant to the lifestyle interventions such as diet and exercise. In this paper, we discuss possible mechanisms by which patients adopting a ketogenic diet (KD) can alleviate many of the unwanted clinical features of LI. This paper is also an effort to provide evidence for the hypothesis of the potency of this dietary intervention for addressing the symptoms of LI. Specifically, we examine the scientific evidence of effectiveness of adopting a KD by patients to alleviate clinical features associated with LI, including excessive and disproportionate lower body adipose tissue (AT) deposition, pain, and reduction in quality of life (QoL). We also explore several clinical features of LI currently under debate, including the potential existence and nature of edema, metabolic and hormonal dysfunction, inflammation, and fibrosis. The effectiveness of a KD on addressing clinical features of LI has been demonstrated in human studies, and shows promise as an intervention for LI. We hope this paper leads to an improved understanding of optimal nutritional management for patients with LI and stimulates future research in this area of study.