The unique biology of lymphatic edema

Multi-omics characterization of lymphedema-induced adipose tissue resulting from breast cancer-related surgery

Secondary lymphedema (LE) following breast cancer-related surgery is a life-long complication, which currently has no cure. LE induces significant regional adipose tissue deposition, requiring liposuction as a treatment. Here, we aimed to elucidate the transcriptional, metabolomic, and lipidomic signature of the adipose tissue developed due to the surgery-induced LE in short- and long-term LE patients and compared the transcriptomic landscape of LE adipose tissue to the obesity-induced adipose tissue. Adipose tissue biopsies were obtained from breast cancer-operated females with LE from the affected and non-affected arms (n = 20 patients). To decipher the molecular properties of the LE adipose tissue, we performed RNA sequencing, metabolomics, and lipidomics combined with bioinformatics analyses. Differential gene expression data from a cohort of lean and obese patients without LE was used for comparisons. Integrative analysis of functional genomics revealed that inflammatory response, cell chemotaxis, and angiogenesis were upregulated biological processes in the LE arm, indicating a sustained inflammation in the edematous adipose tissue; whereas, epidermal differentiation, cell-cell junction organization, water homeostasis, and neurogenesis were downregulated in the LE arm. Surprisingly, only a few genes were found to be the same in the LE-induced and the obesity-induced adipose tissue expansion, indicating a different type of adipose tissue development in these two conditions. In metabolomics analysis, we found reduced levels of a branched-chain amino acid valine in the LE arm and downregulation of the mRNA levels of its transporter SLC6A15. Lipidomics analyses did not show any significant differences between the LE and non-LE arms, suggesting that other factors affect the lipid composition of the adipose tissue more than the LE in these patients. Our results provide a detailed molecular characterization of adipose tissue in secondary LE after breast cancer-related surgery. We also show distinct differences in transcriptomic signatures between LE-induced adipose tissue and obesity-induced adipose tissue, but only minor differences in metabolome and lipidome between the LE and the non-LE arm.

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.

Deep learning-based quantitative estimation of lymphedema-induced fibrosis using three-dimensional computed tomography images

In lymphedema, proinflammatory cytokine-mediated progressive cascades always occur, leading to macroscopic fibrosis. However, no methods are practically available for measuring lymphedema-induced fibrosis before its deterioration. Technically, CT can visualize fibrosis in superficial and deep locations. For standardized measurement, verification of deep learning (DL)-based recognition was performed. A cross-sectional, observational cohort trial was conducted. After narrowing window width of the absorptive values in CT images, SegNet-based semantic segmentation model of every pixel into 5 classes (air, skin, muscle/water, fat, and fibrosis) was trained (65%), validated (15%), and tested (20%). Then, 4 indices were formulated and compared with the standardized circumference difference ratio (SCDR) and bioelectrical impedance (BEI) results. In total, 2138 CT images of 27 chronic unilateral lymphedema patients were analyzed. Regarding fibrosis segmentation, the mean boundary F1 score and accuracy were 0.868 and 0.776, respectively. Among 19 subindices of the 4 indices, 73.7% were correlated with the BEI (partial correlation coefficient: 0.420–0.875), and 13.2% were correlated with the SCDR (0.406–0.460). The mean subindex of Index 2 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\left( {\frac{{P_{Fibrosis\, in\, Affected} - P_{Fibrosis\, in\, Unaffected} }}{{P_{Limb\, in\, Unaffected} }}} \right)$$\end{document}PFibrosisinAffected-PFibrosisinUnaffectedPLimbinUnaffected presented the highest correlation. DL has potential applications in CT image-based lymphedema-induced fibrosis recognition. The subtraction-type formula might be the most promising estimation method.

Surgical Treatment and Rehabilitation Strategies for Upper and Lower Extremity Lymphedema: A Comprehensive Review

Lymphedema is a chronic disabling condition affecting a growing number of patients worldwide. Although lymphedema is not life-threatening, several reports underlined detrimental consequences in terms of distress, pain, functional impairment, and infections with a relevant decrease in quality of life. Currently, there is no cure, and the therapeutic management of this condition aims at slowing down the disease progression and preventing secondary complications. Early diagnosis is paramount to enhance the effects of rehabilitation or surgical treatments. On the other hand, a multidisciplinary treatment should be truly integrated, the combination of microsurgical and reductive procedures should be considered a valid strategy to manage extremity lymphedema, and rehabilitation should be considered the cornerstone of the multidisciplinary treatment not only for patients not suitable for surgical interventions but also before and after surgical procedures. Therefore, a specialized management of Plastic Reconstructive Surgeons and Physical and Rehabilitative Medicine physicians should be mandatory to address patients’ needs and optimize the treatment of this disabling and detrimental condition. Therefore, the aim of this review was to characterize the comprehensive management of lymphedema, providing a broad overview of the potential therapy available in the current literature to optimize the comprehensive management of lymphedema and minimize complications.

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.

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.

Edema assessment and management practice patterns among hand therapists: Survey research

STUDY DESIGN

Survey research.

INTRODUCTION

Recently, the lymphatic system's role in edema management has been reported; however, it is unclear how this evidence has translated into hand therapy practice.

PURPOSE OF THE STUDY

Survey research was performed to explore edema education and management.

METHODS

A 22-question survey containing questions related to edema education and practice was administered to members of the American Society of Hand Therapists. Demographic data were obtained. Frequencies were examined using Chi-square and Fisher exact tests.

RESULTS

A total of 436 members responded to the survey (92% occupational therapists [OTs]; 6% physical therapists [PTs]). Most hand therapists received edema education through on-the-job training and, or continuing education. PTs were more likely to learn the difference between acute, subacute, chronic edema (P < .01; 36% PTs, 17% OTs) and the role of the lymphatic system in edema management (P < .002; 36% PTs, 14% OTs) in entry-level education compared to OTs. OTs with an MS or OTD were more likely to learn the difference between acute, subacute, chronic edema (P < .001; 23% OTD, 24% MS, 10% BS) and the role of the lymphatic system in edema management (P < .004; 19% OTD, 19% MS, 7% BS) in entry-level education than BS-trained OTs. Duration and feel were common ways therapists assessed and identified differences in edema. Many therapists acknowledged the role of the lymphatic system in edema reduction, but responses lacked specificity.

CONCLUSION

The survey results suggest most hand therapists learn edema management outside of academic programs, although this may be changing in OT with advancement of the entry-level degree.

Effectiveness and Safety of Complete Decongestive Therapy of Phase I: A Lymphedema Treatment Study in the Greek Population

Background

Lymphedema is a chronic condition caused by a failure in the lymphatic system that most commonly occurs in the limbs. Complete decongestive therapy (CDT) is the gold standard for lymphedema management.

Objective

To evaluate the effectiveness and safety of complete decongestive therapy (CDT) of phase I in the Greek population with lymphedema.

Methods

The patients’ demographic and clinical characteristics were recorded. CDT was implemented in all patients for 20 sessions in a four-week treatment period. The edema’s (excess volume (EV) and percent of excess volume (PEV)) measurements were carried out four times in the treatment period, whereas the percent reduction of excess volume (PREV) was calculated at the end of phase I. Moreover, we recorded every infection, trauma of skin, and pain of limb during the treatment.

Results

One-hundred five patients with lymphedema were enrolled in the present study, of whom 31.4% had upper limb lymphedema and 68.6% had lower limb lymphedema. All patients with upper limb lymphedema had a secondary type while the corresponding proportion of patients with lower limb lymphedema was 58.3%. A significant reduction (p<0.001) between the pre-treatment and post-treatment values of EV and PEV was found for both upper and lower limb lymphedema. For patients with upper limb lymphedema, the average PREV was 66.5% (interquartile range, 57.3%-80.6%), whereas for patients with lower limb lymphedema, a 71.5% (interquartile range, 64.5%-80.7%) median value was measured. No side effects from the treatment were recorded during CDT.

Conclusion

The proper treatment of the CDT phase I ensures safety and a great reduction in edema in patients with lymphedema that predispose the success of phase II of CDT.

Comparison of a novel algorithm quantitatively estimating epifascial fibrosis in three-dimensional computed tomography images to other clinical lymphedema grading methods

No method has yet been approved for detecting lymphedema fibrosis before its progression. This study assessed the feasibility of computed tomography-based estimation of fibrosis. This observational, cross-sectional study included patients with lymphedema affecting one limb. Three types (maximum, mean, minimum) of computed tomography reticulation indexes were digitally calculated from trans-axial images using absorptive values, and the computed tomography reticulation indexes compared with clinical scales and measurements. Of 326 patients evaluated by at least one of lymphoscintigraphy, bio-electrical impedance, and computed tomography, 24 were evaluated by all three. The mean number of computed tomography scans in these patients was 109. Sixteen patients had breast cancer, seven had gynecologic cancers, and one had primary lymphedema. Mean computed tomography reticulation index (r = 0.52, p < 0.01) and maximal computed tomography reticulation index (r = 0.45, p < 0.05) were significantly associated with time from initial limb swelling to computed tomography. Mean computed tomography reticulation index (r = 0.86, p < 0.01), minimal computed tomography reticulation index (r = 0.79, p < 0.01), and maximal computed tomography reticulation index (r = 0.68, p < 0.01) were significantly associated with International Society of Lymphedema substage. Minimal computed tomography reticulation index correlated with 1-kHz-based bio-electrical impedance ratio (r = -0.46, p < 0.05) and with standardized proximal limb circumference difference ratio (r = 0.45, p < 0.05) of both limbs. Maximal computed tomography reticulation index had a sensitivity of 0.78, specificity of 0.60, and areas under the curve of 0.66 in detecting lymphoscintigraphic stage IV. The algorithm utilizing three-dimensional computed tomography images of epifascial fibrosis may be used as a marker for lymphedema duration, limb swelling, International Society of Lymphedema substage, and interstitial lymphatic fluids of lymphedema. The current approach shows promise in providing an additional method to assist in characterizing and monitoring lymphedema patients.

A Feasibility Study to Examine the Role of Acupuncture to Reduce Symptoms of Lymphoedema after Breast Cancer: A Randomised Controlled Trial

Objective

To determine the feasibility, acceptability and safety of using acupuncture to treat arm lymphoedema in women following treatment for breast cancer.

Methods

We conducted a randomised controlled trial of acupuncture compared with treatment as usual. Twenty women with stable unilateral intransient lymphoedema present for at least 6 months were recruited from Sydney, Australia. The women received 12 acupuncture treatments administered to body and arm points on the non-lymphoedematous limb over 8 weeks, twice weekly for 4 weeks then once weekly for 4 weeks. Outcome measures included an assessment of interest to participate in the trial, identification of successful recruitment strategies, the appropriateness of eligibility criteria and compliance with treatment attendance. Clinical outcomes were assessed at baseline and 8 weeks and included extracellular fluid, lymphoedema symptoms, well-being and safety.

Results

Acupuncture was an acceptable intervention in women with upper limb lymphoedema. Compliance with the treatment protocol was high, with nine women completing all 12 treatments. Outcome forms were completed by 17 women at 8 weeks. No major adverse occurrences, as defined by the study protocol, were reported from the acupuncture group although one woman found the needling uncomfortable, and no study participant experienced an increase in swelling of >10%. There was no change in extracellular fluid or any patient-reported outcome measurement.

Conclusions

Lymphoedema is a persistent symptom experienced by women recovering from breast cancer. Our study suggests that acupuncture may stabilise symptoms and no major safety concerns were identified, so further research is needed.

Trial Registration Number

Australian New Zealand Clinical Trials Registry, http://www.anzctr.org.au ACTRN12612000607875.

[Research progress of vascularized lymph node transfer for extremity lymphedema]

Objective

To review the current progress of clinical and experimental research of vascularized lymph node transfer for lymphedema.

Methods

The domestic and abroad literature about vascularized lymph node transfer in treatment of lymphedema was reviewed and analyzed.

Results

Experimental studies in animal model indicate that vascularized lymph node transfer can improve lymph node survival and show a promising effectiveness in reducing lymphedema. "Lymphatic wick" and "lymph pump" were the two main hypotheses proposed to explain the potential functional mechanism of vascularized lymph node transfer in treatment of lymphedema. Improvement in lymphedema symptoms are reported in most of the clinical trials, but the level of evidence to advocate this procedure in the treatment of lymphedema remains low because of the small number of the cases and problems in their methodologies.

Conclusion

Based on current evidence, vascularized lymph node transfer seems to be a promising treatment for lymphedema, but long-term well-designed studies are required to further explore the effectiveness of this procedure.

Strategies for Avoiding Benzopyrone Hepatotoxicity in Lymphedema Management-The Role of Pharmacogenetics, Metabolic Enzyme Gene Identification, and Patient Selection

INTRODUCTION

Benzopyrones are plant-derived chemicals which have an evidenced degree of clinical efficacy in lymphedema management indicated in past trials. Unfortunately, in some of these cases idiosyncratic hepatotoxicity have been documented in a minority of patients. This review aims to tackle the problem of benzopyrone (particularly coumarin) toxicity by considering their metabolic pathways and identifying relevant alleles needed to take a targeted pharmacogenetic approach in its future use.

METHODS AND RESULTS

The nontoxic 7-hydroxylation and the toxic heterocyclic "ring-splitting" epoxidation pathways are the two main detoxification pathways in the hepatometabolism of coumarin, the former catalyzed by CYP2A6 and the latter by possibly CYP1A and CYP2E. Acetaldehyde dehydrogenase (ALDH) clears toxic aldehyde intermediates. CYP2A6 polymorphism screening methods, including genotyping, by real-time polymerase chain reaction and chromatography-mass spectroscopy functional metabolite assays; efficiency of these techniques are continually improving. ALDH polymorphisms have also been implicated, with clinically viable screening tests, rapid genotyping, and sensitive questionnaires already available for ALDH2*1/ALDH2*2. Dysfunctional polymorphisms of the above genes and others are significantly more prevalent in Eastern Asian populations, uncommon in Caucasian populations. The role of other enzymes/genes in the pathway is yet to be clarified.

CONCLUSION

Although screening techniques are becoming increasingly clinically feasible, uncertainty remains on the link between the genotype, metabolic phenotype, and the exact gene products involved. These must be elucidated further before a targeted pharmacogenomic approach is fully viable. In the meantime, treatment should be avoided in those with vulnerable familial and ethnic descents if used.

Effects of Aqua-Lymphatic Therapy on Lower Extremity Lymphedema: A Randomized Controlled Study

BACKGROUND

The purpose of this study is to investigate the effects of the aqua-lymphatic therapy (ALT) on unilateral lower extremity lymphedema in the maintenance phase.

MATERIALS AND METHODS

This is a randomized controlled trial with a blinded assessor. The study was completed with 30 ALT and 27 control group participants. Foot volume was assessed by a water displacement device, limb volume by circumference measurements, functional capacity by a 6-minute walk test, quality of life by Short Form-36, and social appearance by Social Appearance Anxiety Scale and hopeless by Beck Hopeless Scale. The ALT and the control group had group sessions twice in a week for 6 weeks directed by a physiotherapist.

RESULTS

The mean age of ALT patients was 44.50 ± 13.69 years, whereas that of the control patients was 47.66 ± 16.82 years. After the intervention, both groups' measurement of edema, functional level, quality of life, as well as social and future concerns improved significantly but this improvement was higher in the ALT group (p < 0.05, p ≤ 0.001).

CONCLUSIONS

ALT was found to be a safe effective method for unilateral lower extremity lymphedema patients during the maintenance phase of Complex Decongestive Physiotherapy.

Efficacy of AdipoDren® in Reducing Interleukin-1-Induced Lymphatic Endothelial Hyperpermeability

Lymphatic leakage can be seen as a detrimental phenomenon associated with fluid retention and deposition as well as gain of weight. Moreover, lymphatic dysfunction is associated with an inflammatory environment and can be a substrate for other health conditions. A number of treatments can ameliorate lymphatic vasculature: natural substances have been used as treatment options particularly suitable for their consolidated effectiveness and safety profile. Here we report the protective effect of AdipoDren®, an association of a series of plant-derived natural complexes, on lymphatic endothelium permeability promoted by interleukin-1 beta (IL-1β) and the associated molecular mechanisms. AdipoDren® demonstrated a protective effect on dermal lymphatic endothelial cell permeability increased by IL-1β. Reduced permeability was due to the maintenance of tight junctions and cell-cell localisation of occludin and zonula occludens-1 (ZO-1). Moreover, AdipoDren® reduced the expression of the inflammatory key element cyclooxygenase-2 (COX-2), while not altering the levels of endothelial and inducible nitric oxide synthases (eNOS and iNOS). The upregulation of antioxidant enzymatic systems (catalase and superoxide dismutase-1, SOD-1) and the downregulation of pro-oxidant markers (p22 phox subunit of NADPH oxidase) were also evident. In conclusion, AdipoDren® would be useful to ameliorate conditions of altered lymphatic vasculature and to support the physiological functionality of the lymphatic endothelium.

Vascularized Lymph Node Transfer: A Review of the Current Evidence

Over the past decade, lymph node transfer has rapidly gained popularity among plastic surgeons for the treatment of chronic lymphedema because of the initial promising results and its unique technical advantages compared with the other reconstructive options. However, its functional mechanism is still a matter of great debate, and some concerning reports have emerged regarding the safety of this procedure in patients with chronic lymphedema. The authors review the literature on the experimental and clinical evidence for lymph node transfer, discuss its proposed functional mechanisms, review the potential risk of iatrogenic lymphedema following this procedure, and discuss the suggested strategies to avoid this complication.

Validation of the Lymphoedema Quality-of-Life Questionnaire (LYMQOL) in Dutch Patients Diagnosed with Lymphoedema of the Lower Limbs

BACKGROUND

The Lymphoedema Quality-of-Life Questionnaire is a validated disease-specific instrument to measure the impact of lymphoedema on patients' lives. In this study, we tested its psychometric properties and validated the use of the questionnaire in its Dutch translation.

METHODS

We obtained the answers to a standardised questionnaire, including Lymphoedema Quality-of-Life Questionnaire and Short-Form (36) Health Survey, twice at an interval of 2 weeks in 60 patients with lower limb lymphoedema. Feasibility was tested on the basis of missing responses and response distribution. Structure was studied using factor analysis. The reliability of the Lymphoedema Quality-of-Life Questionnaire was assessed using Crohnbach's α and test-retest reliability. Construct validity was tested by correlating Lymphoedema Quality-of-Life Questionnaire scores with the Short-Form (36) Health Survey scores.

RESULTS

The response rate was 88.2%. One of the 22 items missed >10% of responses; another showed a borderline ceiling effect. Internal consistency was good and test-retest reliability was excellent. The Lymphoedema Quality-of-Life Questionnaire correlated well with the physical component of the Short-Form (36) Health Survey and moderately with the mental component, suggesting that its construct validity was good.

CONCLUSION

The Dutch Lymphoedema Quality-of-Life Questionnaire can be used for health-related quality-of-life research in lower limb lymphoedema patients.

Lymph transport in rat mesenteric lymphatics experiencing edemagenic stress

OBJECTIVE

To assess lymphatic flow adaptations to edema, we evaluated lymph transport function in rat mesenteric lymphatics under normal and increased fluid volume (edemagenic) conditions in situ.

METHODS

Twelve rats were infused with saline (intravenous infusion, 0.2 mL/min/100 g body weight) to induce edema. We intravitally measured mesenteric lymphatic diameter and contraction frequency, as well as lymphocyte velocity and density before, during, and after infusion.

RESULTS

A 10-fold increase in lymphocyte velocity (0.1-1 mm/s) and a sixfold increase in flow rate (0.1-0.6 μL/min), were observed post infusion, respectively. There were also increases in contraction frequency and fractional pump flow one minute post infusion. Time-averaged wall shear stress increased 10 fold post infusion to nearly 1.5 dynes/cm(2) . Similarly, maximum shear stress rose from 5 to 40 dynes/cm(2) .

CONCLUSIONS

Lymphatic vessels adapted to edemagenic stress by increasing lymph transport. Specifically, the increases in lymphatic contraction frequency, lymphocyte velocity, and shear stress were significant. Lymph pumping increased post infusion, though changes in lymphatic diameter were not statistically significant. These results indicate that edemagenic conditions stimulate lymph transport via increases in lymphatic contraction frequency, lymphocyte velocity, and flow. These changes, consequently, resulted in large increases in wall shear stress, which could then activate NO pathways and modulate lymphatic transport function.

Validity of soft-tissue thickness of calf measured using MRI for assessing unilateral lower extremity lymphoedema secondary to cervical and endometrial cancer treatments

AIM

To determine whether soft-tissue thickness of the calf measured using MRI could be valid for assessing unilateral lower extremity lymphoedema (LEL) secondary to cervical and endometrial cancer treatments.

MATERIALS AND METHODS

Seventy women with unilateral LEL and 25 without LEL after cervical or endometrial cancer treatments underwent MRI examinations of their calves. Total thickness of soft-tissue (TT), muscle thickness (MT), and subcutaneous tissue thickness (STT) of the calf, and the difference between the affected and contralateral unaffected calf regarding TT (DTT), MT (DMT), and STT (DSTT) were obtained using fat-suppressed T2-weighted imaging in the middle of the calves. The volume of the calf and difference in volume (DV) between calves were obtained by the method of water displacement. Statistical analysis was performed to determine the validity of MRI measurements by volume measurements in staging LEL.

RESULTS

There was a close correlation between volume and TT for the affected (r = 0.927) or unaffected calves (r = 0.896). STT of the affected calf, and DTT or DSTT of the calves were closely correlated with volume of the affected calf or DV of the calves (all p < 0.05). Multivariate analysis showed significant differences in TT, STT, volume of the affected calf, DTT, DSTT, and DV between stages except in volume of the affected calf or in DV between stage 0 and 1. For staging LEL, DSTT showed the best discrimination ability among all the parameters.

CONCLUSIONS

Soft-tissue thickness of the calf measured at MRI could be valid for quantitatively staging unilateral LEL, and DSTT of the calves could be the best classifying factor.

Development of the lymphoedema genito-urinary cancer questionnaire

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

The lymphatics and the inflammatory response: lessons learned from human lymphedema

In lymphedema, there is a profound predisposition to infection with bacterial pathogens. It therefore seems appropriate to reconsider our unique functional definition of the lymphatic structures within a circulatory construct. While the lymphatics unquestionably fulfill a vital circulatory function, it seems more appropriate to view this complex network, comprised both of endothelial-lined vessels and of lymphoid tissue, as the nexus between the circulatory and immune systems. Viewed in this fashion, it becomes evident that the complex biology of regional lymphatic disruption is a manifestation of the interplay between these two vital bodily functions. Experimental lymph stasis in murine model has been utilized to effectively demonstrate the pathological attributes of human lymphedema, namely, inflammation, fat deposition, and fibrosis. Large-scale transcriptional corroborates the role of inflammatory mechanisms. The murine studies have set the stage for subsequent translational investigation of human lymphedema. Many of the gene expression pathways invoked by lymphedema are relevant to the inflammatory response and have provided a pragmatic approach to the successful identification of potentially relevant circulating biomarkers for human lymphedema.

Adrenomedullin haploinsufficiency predisposes to secondary lymphedema

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

Lymphatic and angiogenic candidate genes predict the development of secondary lymphedema following breast cancer surgery

The purposes of this study were to evaluate for differences in phenotypic and genotypic characteristics in women who did and did not develop lymphedema (LE) following breast cancer treatment. Breast cancer patients completed a number of self-report questionnaires. LE was evaluated using bioimpedance spectroscopy. Genotyping was done using a custom genotyping array. No differences were found between patients with (n = 155) and without LE (n = 387) for the majority of the demographic and clinical characteristics. Patients with LE had a significantly higher body mass index, more advanced disease and a higher number of lymph nodes removed. Genetic associations were identified for four genes (i.e., lymphocyte cytosolic protein 2 (rs315721), neuropilin-2 (rs849530), protein tyrosine kinase (rs158689), vascular cell adhesion molecule 1 (rs3176861)) and three haplotypes (i.e., Forkhead box protein C2 (haplotype A03), neuropilin-2 (haplotype F03), vascular endothelial growth factor-C (haplotype B03)) involved in lymphangiogensis and angiogenesis. These genetic associations suggest a role for a number of lymphatic and angiogenic genes in the development of LE following breast cancer treatment.

Reduced incidence of breast cancer-related lymphedema following mastectomy and breast reconstruction versus mastectomy alone

BACKGROUND

As breast cancer survivorship has increased, so has an awareness of the morbidities associated with its treatment. The incidence of breast cancer-related lymphedema has been reported to be 8 to 30 percent in all breast cancer survivors. To determine whether breast cancer reconstruction has an impact on the incidence of breast cancer-related lymphedema, the authors compared its incidence in patients who underwent mastectomy with reconstruction versus mastectomy alone.

METHODS

All patients who underwent mastectomy, with or without immediate breast reconstruction, between 2001 and 2006, were identified through a search of prospective institutional databases. To reduce variation caused by known predictive factors, the individuals were cross-matched for age, axillary intervention, and postoperative axillary irradiation. The incidence of lymphedema was based on the presence of arm edema that lasted more than 6 months and was documented clinically.

RESULTS

Of the 574 cross-matched patients included in the study, 78 (6.8 percent) developed lymphedema (21 with reconstructed breasts and 57 with unreconstructed breasts). Patients who did not undergo reconstruction were significantly more likely to develop breast cancer-related lymphedema (9.9 percent versus 3.7 percent; p < 0.001). Postoperative axillary radiation therapy (p < 0.001), one or more positive lymph nodes (p = 0.010), and body mass index of 25 or greater (p = 0.021) were also associated with an increased incidence of lymphedema. Reconstruction patients developed lymphedema significantly later than nonreconstruction patients (p < 0.001).

CONCLUSION

Patients who undergo breast reconstruction have a lower incidence and a delay in onset of breast cancer-related lymphedema compared with patients who undergo mastectomy alone.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Update on the biology and treatment of lymphedema

OPINION STATEMENT

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

Normal interstitial flow is critical for developmental lymphangiogenesis in the zebrafish

BACKGROUND

The lymphatic system plays a critical role in the body's fluid and protein homeostasis, immune regulation, and dietary fat absorption. One of the major pathologies of the lymphatic system is primary lymphedema, which occurs in approximately 0.6% of live births and is caused by missing or impaired lymphatic vessels. Although there is a great need for medical intervention into diseases of the lymphatic system, very little is known about its development or how it maintains integrity over time. Recent studies have suggested that biophysical components, such as local extracellular fluid flow, may be important factors during initiation of lymphangiogenesis. We hypothesize that interstitial fluid flow functions as an important morphoregulator during developmental lymphangiogenesis.

METHODS AND RESULTS

In the present study we use pharmacological agents and a mutant fish line to modulate interstitial flow. Our data confirm that a sufficient increase or decrease in interstitial flow can profoundly affect lymphatic patterning and may result in a lymphedema-like phenotype. Proper interstitial flow appears to be necessary during LEC migration for proper lymphatic development.

CONCLUSIONS

These results support the contention that interstitial flow is an important morphoregulator of developmental lymphangiogenesis.

Unilateral psoriasis in a woman with ipsilateral post-mastectomy lymphedema

Psoriasis is a multi-factorial disease with various clinical manifestations. We present a case of unilateral psoriasis associated with ipsilateral lymphedema that developed after mastectomy for breast cancer. A 42-year-old Korean woman was referred to our clinic with a 1-month history of multiple erythematous scaly patches on the right arm, back, and breast and was diagnosed with psoriasis by a skin biopsy. Three years previously, she had been diagnosed with breast cancer (T1N2), underwent a right quadrantectomy and axillary lymph node dissection, and completed adjuvant chemotherapy followed by high-dose adjuvant radiotherapy. She had started rehabilitation therapy on the right arm for secondary lymphedema 30 months previously. Because of the long interval between radiation and psoriasis, we speculated that changes in the local milieu caused by the lymphedema might be a causative factor. We hereby report a rare case of unilateral psoriasis following post-mastectomy lymphedema.

Rare adipose disorders (RADs) masquerading as obesity

Rare adipose disorders (RADs) including multiple symmetric lipomatosis (MSL), lipedema and Dercum's disease (DD) may be misdiagnosed as obesity. Lifestyle changes, such as reduced caloric intake and increased physical activity are standard care for obesity. Although lifestyle changes and bariatric surgery work effectively for the obesity component of RADs, these treatments do not routinely reduce the abnormal subcutaneous adipose tissue (SAT) of RADs. RAD SAT likely results from the growth of a brown stem cell population with secondary lymphatic dysfunction in MSL, or by primary vascular and lymphatic dysfunction in lipedema and DD. People with RADs do not lose SAT from caloric limitation and increased energy expenditure alone. In order to improve recognition of RADs apart from obesity, the diagnostic criteria, histology and pathophysiology of RADs are presented and contrasted to familial partial lipodystrophies, acquired partial lipodystrophies and obesity with which they may be confused. Treatment recommendations focus on evidence-based data and include lymphatic decongestive therapy, medications and supplements that support loss of RAD SAT. Associated RAD conditions including depression, anxiety and pain will improve as healthcare providers learn to identify and adopt alternative treatment regimens for the abnormal SAT component of RADs. Effective dietary and exercise regimens are needed in RAD populations to improve quality of life and construct advanced treatment regimens for future generations.

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

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

ROCK and cAMP promote lymphatic endothelial cell barrier integrity and modulate histamine and thrombin-induced barrier dysfunction

BACKGROUND

There is recent evidence that inflammatory signals can modulate lymphatic vessel permeability, but current understanding of the mechanisms regulating lymphatic endothelial barrier function is limited. The objectives of this study were to 1) investigate whether inflammatory mediators that increase microvascular permeability also cause barrier dysfunction of lymphatic endothelial cell monolayers, and 2) determine the roles of signaling pathways that affect intercellular junctions and cell contraction in lymphatic endothelial barrier function.

METHODS AND RESULTS

Transendothelial electrical resistance (TER) of confluent adult human microlymphatic endothelial cells of dermal origin (HMLEC-d) served as an indicator of lymphatic endothelial barrier function. Human umbilical vein endothelial cells (HUVEC) were used to model blood-tissue barrier function. The inflammatory mediators histamine and thrombin each caused a decrease in TER of HMLEC-d and HUVEC monolayers, with notable differences between the two cell types. Treatment with 8-Br-cAMP enhanced HMLEC-d barrier function, which limited histamine and thrombin-induced decreases in TER. Blockade of myosin light chain kinase (MLCK) with ML-7 did not affect histamine or thrombin-induced decreases in TER. Treatment with the Rho kinase (ROCK) inhibitor Y-27632 caused a decrease in HMLEC-d barrier function.

CONCLUSIONS

These data show that inflammatory mediators can cause lymphatic endothelial barrier dysfunction, although the responses are not identical to those seen with blood endothelial cells. ROCK and cAMP both promote lymphatic endothelial barrier function, however ROCK appears to also serve as a mediator of histamine and thrombin-induced barrier dysfunction.

Causes and consequences of lymphatic disease

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

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

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

Development of the endothelium: an emphasis on heterogeneity

The endothelium is composed of specialized epithelial cells that line the vasculature, the lymph vessels, and the heart. These endothelial cells are characterized by their stratification and are connected via intercellular junctions that confer specific permeability. Although all endothelium acts as a barrier, considerable heterogeneity exists among different organs and even within vessels. During development, the endothelial cells are specified before they migrate to their final destination, and then they commit to an arterial or venous fate. From the venous endothelial cell population, a subset of cells is further specified as lymphatic endothelium. The endothelium can be highly permeable, as in the lymph vessels, or impenetrable, as in the blood-brain barrier. These differences arise during development and are orchestrated through a series of signaling pathways. This review details how endothelial cells arise and are directed to their specific fate, specifically targeting what differentiates endothelial populations.