Fibrosis and secondary lymphedema: chicken or egg?

Identification Of A Higher Risk Lymphedema Phenotype And Associations With Cytokine Gene Polymorphisms

CONTEXT

Breast cancer-related lymphedema (BCRL) is chronic condition that occurs in 5% to 75% of women following treatment for breast cancer. However, little is known about the risk factors and mechanisms associated with a worse BCRL profile.

OBJECTIVES

Identify distinct BCRL profiles in women with the condition (i.e., lower vs. higher risk phenotype) and evaluate for associations with pro- and anti-inflammatory genes.

METHODS

Latent class profile analysis (LCPA) was used to identify the BCRL profiles using phenotypic characteristics evaluated prior to surgery. Candidate gene analyses were done to identify cytokine genes associated with the two BCRL profiles.

RESULTS

Of the 155 patients evaluated, 35.5% (n = 55) were in the Lower and 64.5% (n = 100) were in the Higher Risk classes. Risk factors for membership in the Higher class included: lower functional status, having sentinel lymph node biopsy, axillary lymph node dissection, mastectomy, higher number of positive lymph nodes, and receipt of chemotherapy. Polymorphisms for interleukin (IL)1-beta and IL6 were associated with membership in the Higher Risk class.

CONCLUSION

The readily available and clinically relevant phenotypic characteristics associated with a worse BCRL profile can be used by clinicians to identify higher risk patients. If confirmed, these characteristics can be tested in predictive risk models. In addition, the candidate gene findings may guide the development of mechanistically-based interventions to decrease the risk of BCRL.

Efficacy and Feasibility of Short-Stretch Compression Therapy for Filarial Lymphedema in Sri Lanka

The WHO-recommended essential package of care (EPC) for filarial limb lymphedema consists of daily limb washing, entry lesion management, limb protection, exercises, and elevation. Decongestive therapy (DT) with compression bandaging by trained lymphedema therapists adds additional benefit but is unavailable for most in low- and middle-income countries (LMICs). To determine whether DT using self-adjustable, short-stretch compression garments (SSCG), prefitted using portable, three-dimensional infrared imaging (3DII), would be effective and feasible in LMIC settings, we conducted a pilot 6-week, interventional, single-group, open-label pilot study in Galle, Sri Lanka. Ten participants with Dreyer stage 3 lymphedema used SSCG for 2 weeks after a 4-week lead-in EPC period. Effect of EPC and compression on quality of life was assessed using the 12-item WHO Disability Assessment Schedule 2.0 (WHODAS 2.0). Median participant age was 73 years (range: 32-85 years). Median percent limb volume reduction due to compression was 11.3% (range: 1.1-27.2%). WHODAS 2.0 scores did not change significantly between enrollment and study end. Garment acceptability was high throughout the study. These results provide proof of concept for 3DII-enabled SSCG in LMICs where trained therapists for filarial lymphedema may not be available.

High Pressure 3 × 30 Minute Compression Methods for Advanced Lower Limb Lymphedema Patients

Introduction: In advanced lymphedema of lower limbs, stage III bandaging under the routinely applied pressure of 40-60 mmHg remains largely ineffective. This is caused by skin and subcutaneous tissue stiffness due to fibrosis. Edema fluid accumulates deep in the subcutaneous tissue. Evacuating this fluid requires a high external compression force to overcome the resistance of fibrous tissue. We aimed to investigate the effectiveness of the compression method, with high pressure lasting for 3 days. Methods and Results: Twenty-one patients with lower limb lymphedema, stage III, of the postinflammatory type were included. Patients with acute inflammatory symptoms, venous thrombosis, profuse varicose veins, diabetes, and cardiac insufficiency with edema were excluded. A 10-cm-wide rubber bandage was applied to the foot and calf. The interface pressure measured using PicoPress ranged from 58 to 120 mmHg. Skin and deep tissue tonometry, skin water concentration, leg circumference, and drop of interface pressure were measured. Ultrasound examination was done before and after each compression session. The calf circumference decreased by 15.9 ± 5.4%, deep tissue stiffness by 58.9 ± 18.9%, skin stiffness by 69.6 ± 13.5%, and skin water concentration by 43.8 ± 11.5%. Interface pressure dropped to 66.3 mmHg (28-110 mmHg); ultrasonography images showed less fluid in the tissue. Conclusions: High-pressure 30-minute leg compression can remove excess edema fluid within 3 days and enable adjustment of nonstretch compression stockings. This method is more effective in advanced lymphedema at the beginning of therapy than the standard 30-50-mmHg bandaging as it provides an immediate effect.

Para- and Transcellular Transport Kinetics of Nanoparticles across Lymphatic Endothelial Cells

Lymphatic vessels have received significant attention as drug delivery targets, as they shuttle materials from peripheral tissues to the lymph nodes, where adaptive immunity is formed. Delivery of immune modulatory materials to the lymph nodes via lymphatic vessels has been shown to enhance their efficacy and also improve the bioavailability of drugs when delivered to intestinal lymphatic vessels. In this study, we generated a three-compartment model of a lymphatic vessel with a set of kinematic differential equations to describe the transport of nanoparticles from the surrounding tissues into lymphatic vessels. We used previously published data and collected additional experimental parameters, including the transport efficiency of nanoparticles over time, and also examined how nanoparticle formulation affected the cellular transport mechanisms using small molecule inhibitors. These experimental data were incorporated into a system of kinematic differential equations, and nonlinear, least-squares curve fitting algorithms were employed to extrapolate transport coefficients within our model. The subsequent computational framework produced some of the first parameters to describe transport kinetics across lymphatic endothelial cells and allowed for the quantitative analysis of the driving mechanisms of transport into lymphatic vessels. Our model indicates that transcellular mechanisms, such as micro- and macropinocytosis, drive transport into lymphatics. This information is crucial to further design strategies that will modulate lymphatic transport for drug delivery, particularly in diseases like lymphedema, where normal lymphatic functions are impaired.

Apelin-VEGF-C mRNA delivery as therapeutic for the treatment of secondary lymphedema

Secondary lymphedema (LD) corresponds to a severe lymphatic dysfunction leading to the accumulation of fluid and fibrotic adipose tissue in a limb. Here, we identified apelin (APLN) as a powerful molecule for regenerating lymphatic function in LD. We identified the loss of APLN expression in the lymphedematous arm compared to the normal arm in patients. The role of APLN in LD was confirmed in APLN knockout mice, in which LD is increased and associated with fibrosis and dermal backflow. This was reversed by intradermal injection of APLN-lentivectors. Mechanistically, APLN stimulates lymphatic endothelial cell gene expression and induces the binding of E2F8 transcription factor to the promoter of CCBE1 that controls VEGF-C processing. In addition, APLN induces Akt and eNOS pathways to stimulate lymphatic collector pumping. Our results show that APLN represents a novel partner for VEGF-C to restore lymphatic function in both initial and collecting vessels. As LD appears after cancer treatment, we validated the APLN-VEGF-C combination using a novel class of nonintegrative RNA delivery LentiFlash® vector that will be evaluated for phase I/IIa clinical trial.

Lymphatic Vascular Insufficiency and Focal Edema in Early Stages of Noncancer-Related Lymphedema

Introduction: Lymph flows along the lymphatics due to spontaneous contraction. However, injury and inflammation may deteriorate lymphatic' s endothelial and muscle cells and valves. In consequence, lymphatic vessels (LVs) become insufficient. Their contraction strength and rate slow down, and then lymph flow stops. Our study aimed to investigate the changes in lymph flow in early lymphedema cases. Methods and Results: In 36 patients with unilateral lymphedema stages 0 and I, we performed indocyanine green (ICG) lymphography, lymphoscintigraphy, skin water concentration, and stiffness measurement. We compared lymph flow velocity, LVs' appearance, contraction pattern, and rate between swollen and healthy limbs. ICG lymphography revealed (1) slower lymph flow after 3 minutes of foot movement; in lower calf level, lymphatics are seen in 22 (61.1%) swollen limbs compared with 36 (100%) healthy limbs (p < 0.0001); (2) dye spots in the foot (47.1%) and calves (13.9%) in swollen limbs; (3) dilated foot (41.7%) and calves' lymphatics (52.8%); (4) different patterns of lymphatics contractility with slower contractions rate and (5) higher fluorescent intensity in edema limbs. There was higher skin water concentration at foot and ankle level and higher skin stiffness in the foot. Conclusions: Our studies have shown the distortion in lymphatic function as dilatation, slower lymph flow, slower contraction rate, presence of areas with occluded lymphatics (dermal backflow in foot and calves-focal edema), and higher skin water concentration in these regions in limbs with early lymphedema. ICG lymphography can be used for the early detection of LV insufficiency, which allows early prophylactic implementation.

Etiology and treatment of cancer-related secondary lymphedema

Lymphedema and specifically cancer-related lymphedema is not the main focus for both patients and physicians dealing with cancer. Its etiology is an unfortunate complication of cancer treatment. Although lymphedema treatments have gained an appreciable consensus, many practitioners have developed and prefer their own specific protocols and this is especially true for conventional (manual) versus surgical treatments. This collection of presentations explores the incidence and genetics of cancer-related lymphedema, early detection and monitoring techniques, both conventional and operative treatment options, and the importance and role of exercise for patients with cancer-related lymphedema. These assembled presentations provide valuable insights into the challenges and opportunities presented by cancer-related lymphedema including the latest research, treatments, and exercises available to improve patient outcomes and quality of life.

Topical captopril: a promising treatment for secondary lymphedema

Transforming growth factor-beta 1 (TGF-β1)-mediated tissue fibrosis is an important regulator of lymphatic dysfunction in secondary lymphedema. However, TGF-β1 targeting can cause toxicity and autoimmune complications, limiting clinical utility. Angiotensin II (Ang II) modulates intracellular TGF-β1 signaling, and inhibition of Ang II production using angiotensin-converting enzyme (ACE) inhibitors, such as captopril, has antifibrotic efficacy in some pathological settings. Therefore, we analyzed the expression of ACE and Ang II in clinical lymphedema biopsy specimens from patients with unilateral breast cancer-related lymphedema (BCRL) and mouse models, and found that cutaneous ACE expression is increased in lymphedematous tissues. Furthermore, topical captopril decreases fibrosis, activation of intracellular TGF-β1 signaling pathways, inflammation, and swelling in mouse models of lymphedema. Captopril treatment also improves lymphatic function and immune cell trafficking by increasing collecting lymphatic pumping. Our results show that the renin-angiotensin system in the skin plays an important role in the regulation of fibrosis in lymphedema, and inhibition of this signaling pathway may hold merit for treating lymphedema.

The Future of Lymphedema: Potential Therapeutic Targets for Treatment

Purpose of Review

This review aims to summarize the current knowledge regarding the pharmacological interventions studied in both experimental and clinical trials for secondary lymphedema.

Recent Findings

Lymphedema is a progressive disease that results in tissue swelling, pain, and functional disability. The most common cause of secondary lymphedema in developed countries is an iatrogenic injury to the lymphatic system during cancer treatment. Despite its high incidence and severe sequelae, lymphedema is usually treated with palliative options such as compression and physical therapy. However, recent studies on the pathophysiology of lymphedema have explored pharmacological treatments in preclinical and early phase clinical trials.

Summary

Many potential treatment options for lymphedema have been explored throughout the past two decades including systemic agents and topical approaches to decrease the potential toxicity of systemic treatment. Treatment strategies including lymphangiogenic factors, anti-inflammatory agents, and anti-fibrotic therapies may be used independently or in conjunction with surgical approaches.

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

BACKGROUND

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

AIMS

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

MATERIALS & METHODS

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

RESULTS

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

CONCLUSION

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

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

SUMMARY

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

Fibroblast-Generated Extracellular Matrix Guides Anastomosis during Wound Healing in an Engineered Lymphatic Skin Flap

A healthy lymphatic system is required to return excess interstitial fluid back to the venous circulation. However, up to 49% of breast cancer survivors eventually develop breast cancer-related lymphedema due to lymphatic injuries from lymph node dissections or biopsies performed to treat cancer. While early-stage lymphedema can be ameliorated by manual lymph drainage, no cure exists for late-stage lymphedema when lymph vessels become completely dysfunctional. A viable late-stage treatment is the autotransplantation of functional lymphatic vessels. Here we report on a novel engineered lymphatic flap that may eventually replace the skin flaps used in vascularized lymph vessel transfers. The engineered flap mimics the lymphatic and dermal compartments of the skin by guiding multi-layered tissue organization of mesenchymal stem cells and lymphatic endothelial cells with an aligned decellularized fibroblast matrix. The construct was tested in a novel bilayered wound healing model and implanted into athymic nude rats. The in vitro model demonstrated capillary invasion into the wound gaps and deposition of extracellular matrix fibers, which may guide anastomosis and vascular integration of the graft during wound healing. The construct successfully anastomosed in vivo, forming chimeric vessels of human and rat cells. Overall, our flap replacement has high potential for treating lymphedema.

Lymphangiogenesis, a potential treatment target for myocardial injury

The lymphatic vascular system is crucial for the regulation of tissue fluid homeostasis, lipid metabolism, and immune function. Cardiac injury quickly leads to myocardial edema, cardiac lymphatic dysfunction, which ultimately results in myocardial fluid imbalance and cardiac dysfunction. Therefore, lymphangiogenesis-targeted therapy may improve the recovery of myocardial function post cardiac ischemia as observed in myocardial infarction (MI). Indeed, a promising strategy for the clinical treatment of MI relies on vascular endothelial growth factor-C (VEGF-C)-targeted therapy, which promotes lymphangiogenesis. However, much effort is needed to identify the mechanisms of lymphatic transport in response to heart disease. This article reviews regulatory factors of lymphangiogenesis, and discusses the effects of lymphangiogenesis on cardiac function after cardiac injury and its regulatory mechanisms. The involvement of stem cells on lymphangiogenesis was also discussed as stem cells could differentiate into lymphatic endothelial cells (LECs) and stimulate phenotype of LECs.

Prediction of breast cancer-related lymphedema risk after postoperative radiotherapy via multivariable logistic regression analysis

PURPOSE

We identified novel clinical and dosimetric prognostic factors affecting breast cancer-related lymphedema after postoperative radiotherapy (RT) and developed a multivariable logistic regression model to predict lymphedema in these patients.

METHODS AND MATERIALS

In total, 580 patients with unilateral breast cancer were retrospectively reviewed. All patients underwent breast surgery and postoperative RT with or without systemic treatment in 2015. Among the 580 patients, 532 with available RT plan data were randomly divided into training (n=372) and test (n=160) cohorts at a 7:3 ratio to generate and validate the lymphedema prediction models, respectively. An area under the curve (AUC) value was estimated to compare models.

RESULTS

The median follow-up duration was 5.4 years. In total, 104 (17.9%) patients experienced lymphedema with a cumulative incidence as follows: 1 year, 10.5%; 3 years, 16.4%; and 5 years, 17.6%. Multivariate analysis showed that body mass index ≥25 kg/m2 (hazard ratio [HR] 1.845), dissected lymph nodes ≥7 (HR 1.789), and taxane-base chemotherapy (HR 4.200) were significantly associated with increased lymphedema risk. Conversely, receipt of RT at least 1 month after surgery reduced the risk of lymphedema (HR 0.638). A multivariable logistic regression model using the above factors, as well as the minimum dose of axillary level I and supraclavicular lymph node, was created with an AUC of 0.761 and 0.794 in the training and test cohorts, respectively.

CONCLUSIONS

Our study demonstrated that a shorter interval from surgery to RT and other established clinical factors were associated with increased lymphedema risk. By combining these factors with two dosimetric parameters, we propose a multivariable logistic regression model for breast cancer-related lymphedema prediction after RT.

Single and combined impacts of irradiation and surgery on lymphatic vasculature and fibrosis associated to secondary lymphedema

Lymphedema (LD) refers to a condition of lymphatic dysfunction associated with excessive fluid accumulation, fibroadipose tissue deposition and swelling. In industrialized countries, LD development mainly results from a local disruption of the lymphatic network by an infection or cancer-related surgery (secondary LD). In the absence of efficient therapy, animal models are needed to decipher the cellular and molecular mechanisms underlying LD and test putative drugs. In this study, we optimized and characterized a murine model of LD that combines an irradiation of the mice hind limb and a radical surgery (lymph node resection associated to lymphatic vessel ligation). We investigated the respective roles of irradiation and surgery in LD formation by comparing their impacts, alone or in combination (with different intervention sequences), on eight different features of the pathology: swelling (paw thickness), indocyanine green (ICG) clearance, lymphatic vasculature remodeling, epidermal and dermal thickening, adipocyte accumulation, inflammatory cell infiltration and collagen deposition. This study supports the importance of radiation prior to surgery to experimentally induce a rapid, severe and sustained tissue remodeling harboring the different hallmarks of LD. We provide the first experimental evidence for an excessive deposition of periostin (POSTN) and tenascin-C (TNC) in LD. Through a computerized method of digital image quantification, we established the spatial map of lymphatic expansion, as well as collagen, POSTN and TNC deposition in papillary and reticular dermis of lymphedematous skins. This mouse model is available to study the patho-physiology of LD and test potential therapeutic targets.

A Prospective Study on the Safety and Efficacy of Vascularized Lymph Node Transplant

PURPOSE

While vascularized lymph node transplant (VLNT) has gained popularity, there are a lack of prospective long-term studies and standardized outcomes. The purpose of this study was to evaluate the safety and efficacy of VLNT using all available outcome measures.

METHODS

This was a prospective study on all consecutive patients who underwent VLNT. Outcomes were assessed with 2 patient-reported outcome metrics, limb volume, bioimpedance, need for compression, and incidence of cellulitis.

RESULTS

There were 89 patients with the following donor sites: omentum (73%), axilla (13%), supraclavicular (7%), groin (3.5%). The mean follow-up was 23.7±12 months. There was a significant improvement at 2 years postoperatively across all outcome measures: 28.4% improvement in the Lymphedema Life Impact Scale, 20% average reduction in limb volume, 27.5% improvement in bioimpedance score, 93% reduction in cellulitis, and 34% of patients no longer required compression. Complications were transient and low without any donor site lymphedema.

CONCLUSIONS

VLNT is a safe and effective treatment for lymphedema with significant benefits fully manifesting at 2 years postoperatively. Omentum does not have any donor site lymphedema risk making it an attractive first choice.

Evaluation of Circulating MicroRNAs and Adipokines in Breast Cancer Survivors with Arm Lymphedema

Breast cancer-related lymphedema (BCRL) is a form of secondary lymphedema that is characterized by abnormal swelling of one or both arms due to the accumulation of lymph fluid in the interstitial tissue spaces, resulting from obstruction of the lymphatic vessels due to surgery insults, radiotherapy, or chemotherapy. Due to the multifactorial nature of this condition, the pathogenesis of secondary lymphedema remains unclear and the search for molecular factors associated with the condition is ongoing. This study aimed to identify serum microRNAs and adipokines associated with BCRL. Blood was collected from 113 breast cancer survivors and processed to obtain serum for small RNA-sequencing (BCRL vs. non-BCRL, n = 7 per group). MicroRNAs that were differentially expressed (fold change >1.5, p < 0.05) between lymphedema cases and those without lymphedema were further quantified in a validation cohort through quantitative reverse transcription PCR (BCRL n = 16, non-BCRL, n = 83). Leptin and adiponectin levels were measured in a combined cohort (BCRL n = 23, non-BCRL n = 90) using enzyme-linked immunosorbent assays. Two of the most significantly upregulated microRNAs, miR-199a-3p and miR-151a-3p, were strongly correlated with the onset of lymphedema and diabetes mellitus in the BCRL group. Leptin levels were higher in the BCRL cohort compared to the non-BCRL cohort (p < 0.05). A metabolic syndrome biomarker, the adiponectin/leptin ratio, was found to be lower in the BCRL group than in the non-BCRL group (median: 0.28 vs. 0.41, p < 0.05). Extensive studies on the mechanisms of the identified microRNAs and association of leptin with arm lymphedema may provide new insights on the potential biomarkers for lymphedema that should be followed up in a prospective cohort study.

Breast Cancer Treatment Decreases Serum Levels of TGF-β1, VEGFR2, and TIMP-2 Compared to Healthy Volunteers: Significance for Therapeutic Outcomes?

Various complications from a breast cancer treatment, in the pathogenesis of which excessive tissue fibrosis plays a leading role, are a common pathology. In this study, the levels of TGF-β1, VEGFR-2, and TIMP-2 were determined by the immuno-enzyme serum analysis for patients during the long-term period after breast cancer treatment as potential markers of fibrosis. The single-center study enrolled 92 participants, which were divided into two age-matched groups: (1) 67 patients following breast cancer treatment, and (2) 25 healthy female volunteers. The intergroup analysis demonstrated that the patients after breast cancer treatment showed a decrease in the serum levels of TGF-β1 (U = 666, p < 0.001) and TIMP-2 (U = 637, p < 0.001) as compared to the group of healthy volunteers. The levels of VEGFR-2 in these groups were comparable (U = 1345, p = 0.082). It was also found that the type of treatment, the presence of lymphedema, shoulder joint contracture, and changes in lymphoscintigraphy did not affect the levels of TGF-β1, VEGFR-2, and TIMP-2 within the group of patients after breast cancer treatment. These results may indicate that these biomarkers do not play a leading role in the maintenance and progression of fibrosis in the long-term period after breast cancer treatment. The reduced levels of TGF-β1 and TIMP-2 may reflect endothelial dysfunction caused by the antitumor therapy.

Evaluation of Abdominal Fat Ratio in Patients with Breast Cancer-Related Lymphedema: A Controlled Study

Background: This study aimed to investigate the possible relationship between breast cancer-related lymphedema and central obesity, which is known to be effective in metabolic syndrome and chronic inflammation. Methods and Results: Thirty-six patients (18 lymphedemas, 18 control) enrolled in the study. There was no statistically significant difference in demographic data between the two groups except body mass index (BMI) distribution (p = 0.008). Although 50% of the patients in the study group were obese, this rate was 5.6% in the control group. Although there was a significant difference between the study and control groups in terms of abdominal circumference measurement, there was no significant difference between total and abdominal fat amount and ratios. When BMI and abdominal circumference measurements were evaluated together to predict lymphedema, the area under the curve in abdominal circumference measurement was higher than BMI (0.715 vs. 0.659). In receiver operating characteristic curve analysis, 107 cm of abdominal circumference measurement was determined as cutoff value for lymphedema, with 55% sensitivity and 89% specificity (Youden index: 0.44). Conclusion: Abdominal circumference measurement can be evaluated together with BMI in determining the risk of lymphedema.

Lymphatic Vascular Permeability

Blood vessels have a regulated permeability to fluid and solutes, which allows for the delivery of nutrients and signaling molecules to all cells in the body, a process essential to life. The lymphatic vasculature is the second network of vessels in the body, making up part of the immune system, yet is not typically thought of as having a permeability to fluid and solute. However, the major function of the lymphatic vasculature is to regulate tissue fluid balance to prevent edema, so lymphatic vessels must be permeable to absorb and transport fluid efficiently. Only recently were lymphatic vessels discovered to be permeable, which has had many functional implications. In this review, we will provide an overview of what is known about lymphatic vascular permeability, discuss the biophysical and signaling mechanisms regulating lymphatic permeability, and examine the disease relevance of this new property of lymphatic vessels.

Temporal Changes in Subcutaneous Fibrosis in Patients with Lower Extremity Lymphedema Following Surgery for Gynecologic Cancer: A Computed Tomography-Based Quantitative Analysis

Lymphedema causes inflammation, which provokes fibrosis within the epifascial tissue. Temporal change in fibrosis according to severity of the lymphedema has not been widely investigated. We aimed to study the quantitative changes in epifascial fibrosis during lymphedema treatment using computed tomography (CT). Forty-five patients (mean age: 57.75 ± 11.12 years) who developed lymphedema following gynecologic surgery were included in this retrospective study. Two weeks of complete decongestive therapy and continued self-bandaging or compression garments were prescribed under regular follow-up monitoring. Lower-extremity epifascial fibrosis was quantitatively analyzed on the initial and follow-up CT scans. Circumference, skin fibrosis, subcutaneous tissue, and fibrosis ratio were calculated in the axial scan. Based on the change in lymphedema severity, we divided subjects into ‘improved’ and ‘aggravated’ groups. The affected lower extremities showed higher circumference, more skin fibrosis and subcutaneous tissue, and higher fibrosis ratio than the unaffected sides on initial CT scan. At follow-up, compared to the aggravated group, the improved group showed significant decreases in fibrosis of skin and subcutaneous tissue and fibrosis ratio. Subcutaneous fibrosis was reversible with volume resolution of lymphedema. Therapeutic approaches should be established on the basis of the reversible nature of fibrotic changes in patients with lower extremity lymphedema.

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.

Hypoxia and Hypoxia-Inducible Factors in Lymphedema

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

Vascularized lymph node transplantation successfully reverses lymphedema and maintains immunity in a rat lymphedema model

Vascularized lymph node transplantation (VLNT) has shown inspiring results for the treatment of lymphedema. Nevertheless, it remains unclear how VLNT restores lymphatic drainage and whether or not immunity recovers after surgery. Hindlimb lymphedema model was created using rats with extensive groin and popliteal lymph node removable following with radiotherapy, and the lymphedema was confirmed using indocyanine green (ICG) lymphangiography and micro‐computer tomography for volume measurement. VLNT was performed 1 month later. Volume measurement, ICG lymphangiography, histology, and immune reaction were done 1 month after surgery. VLNT successfully reduced the volume of the lymphedema hindlimb, restored lymphatic drainage function with proven lymphatic channel, and reduced lymphedema‐related inflammation and fibrosis. It promotes lymphangiogenesis shown from ICG lymphangiography, histology, and enhanced lymphangiogenesis gene expression. Dendritic cell trafficking via the regenerated lymphatic channels was successfully restored, and maintained systemic immune response was proved using dinitrofluorobenzene sensitization and challenge. VLNT effectively reduces lymphedema and promotes lymphatic regeneration in the capillary lymphatic but not the collecting lymphatic vessels. Along with the re‐established lymphatic system was the restoration of immune function locally and systemically. This correlated to clinical experience regarding the reduction of swelling and infection episodes after VLNT in lymphedema patients.

Pharmacological Treatment of Secondary Lymphedema

Lymphedema is a chronic disease that results in swelling and decreased function due to abnormal lymphatic fluid clearance and chronic inflammation. In Western countries, lymphedema most commonly develops following an iatrogenic injury to the lymphatic system during cancer treatment. It is estimated that as many as 10 million patients suffer from lymphedema in the United States alone. Current treatments for lymphedema are palliative in nature, relying on compression garments and physical therapy to decrease interstitial fluid accumulation in the affected extremity. However, recent discoveries have increased the hopes of therapeutic interventions that may promote lymphatic regeneration and function. The purpose of this review is to summarize current experimental pharmacological strategies in the treatment of lymphedema.

Computed Tomography-Based Quantitative Analysis of Fibrotic Changes in Skin and Subcutaneous Tissue in Lower Extremity Lymphedema Following Gynecologic Cancer Surgery

Background: Lymphedema produces protein-rich fluids that aggravate inflammation in the skin and subcutaneous tissue. Inflammation then induces fibroadipose tissue deposition and fibrosis. However, few methods have been developed to evaluate the severity of fibrosis. Therefore, we aimed to evaluate the subcutaneous fibrotic changes in lower extremity lymphedema following gynecologic cancer surgery using an image analysis tool, the FIJI software. Methods and Results: Seventy-four patients with lymphedema following gynecologic surgery were enrolled in this study. We quantitatively analyzed the cross-sectional area (CSA) of soft tissue compartments, including subcutaneous tissue with the skin, muscle volume, fibrotic changes in subcutaneous tissue, and the perimeter of skin boundaries. The limb circumference and the CSA of the subcutaneous tissue and skin on the affected side were significantly larger than those on the unaffected side. Fibrotic changes showed the same trend. However, muscle volume patterns were different from those of the other compartments. Some patients showed lower muscle volume on the unaffected side than on the affected side. Circumference and cellulitis significantly affected the extent of fibrotic changes in the skin and subcutaneous tissues. Age and duration of lymphedema did not affect fibrosis. Conclusion: Fibrosis of subcutaneous regions with the skin can be quantitatively calculated using an image analysis tool in lower extremity lymphedema following gynecologic cancer surgery. Edema and cellulitis increase fibrotic changes in the subcutaneous tissue with the skin.

Coagulation in Lymphatic System

The lymphatic system maintains homeostasis of the internal environment between the cells in tissues and the blood circulation. The coagulation state of lymph is determined by conditions of coagulation factors and lymphatic vessels. Internal obliteration, external compression or abnormally increased lymphatic pressure may predispose to localized lymphatic coagulation. In physiological conditions, an imbalance of antithrombin and thrombokinase reduces lymphatic thrombosis. However, the release of factor X by lymphatic endothelium injury may trigger coagulation casacade, causing blockage of lymphatic vessels and lymphedema. Heterogeneity of lymphatic vessels in various tissues may lead to distinct levels and patterns of coagulation in specific lymphatic vessels. The quantitative and qualitative measurement of clotting characteristic reveals longer time for clotting to occur in the lymph than in the blood. Cancer, infections, amyloidosis and lymph node dissection may trigger thrombosis in the lymphatic vessels. In contrast to venous or arterial thrombosis, lymphatic thrombosis has rarely been reported, and its actual prevalence is likely underestimated. In this review, we summarize the mechanisms of coagulation in lymphatic system, and discuss the lymphatic thrombosis-related diseases.

Outcomes analysis of microsurgical physiologic lymphatic procedures for the upper extremity from the United States National Surgical Quality Improvement Program

INTRODUCTION

Physiologic microsurgical procedures to treat lymphedema include vascularized lymph node transfer (VLNT) and lymphovenous bypass (LVB). The purpose of this study was to assess 30-day outcomes of VLNT and LVB using the National Surgical Quality Improvement Program (NSQIP) database.

METHODS

NSQIP was queried (2012-2018) for lymphatic procedures for upper extremity lymphedema after mastectomy. Prophylactic lymphatic procedures and those for lower extremity lymphedema were excluded. Outcomes were assessed for three groups: LVB, VLNT, and patients who had procedures simultaneously (VLNA+LVB). Primary outcomes measured were operative time, 30-day morbidities, and hospital length of stay.

RESULTS

The study included 199 patients who had LVB (n = 43), VLNT (n = 145), or VLNT+LVB (n = 11). There was no difference in co-morbidities between the groups (p = 0.26). 30-day complication rates including unplanned reoperation (6.9% VLNT vs. 2.3% LVB) and readmission (0.69% VLNT vs. none in LVB) were not statistically significant (p = 0.54). Surgical site infection, wound complications, deep vein thromboembolism, and cardiac arrest was also similar among the three groups. Postoperative length of stay for VLNT (2.5 days± 2.3), LVB (1.9 days± 1.9), and VLNT+LVB (2.8 days± 0.3) did not differ significantly (p = 0.20). Operative time for LVB (305.4 min ± 186.7), VLNT (254 min ± 164.4), and VLNT+LVB (295.3 min ± 43.2) was not significantly different (p = 0.21).

CONCLUSIONS

Our analysis of the NSQIP data revealed that VLNT and LVB are procedures with no significant difference in perioperative morbidity. Our results support that choice of VLNT versus LVB can be justifiably made per the surgeon's preference and experience as the operations have similar complication rates.

Hardness Sensed by Skin Palpation in Legs with Lymphedema Is Predominantly Correlated with Dermal Thickening

Background: We aimed to clarify whether pathological changes in skin and subcutaneous tissue with lymphedema affected the skin hardness sensed by palpation. Methods and Results: In 50 patients with unilateral legs with lymphedema (LE), the skin hardness of the lower inner thigh and lower inner calf was determined using a scale ranging from 1 (softest) to 7 (hardest) based on palpation. Then, the skin hardness was correlated with the measurements of skin/subcutaneous tissue ultrasonography images obtained from the palpated parts. Multivariate logistic regression analysis demonstrated that dermal thickness was a significant factor that affected the difference in skin hardness between the LE and the contralateral asymptomatic leg for both thigh (p < 0.05) and calf (p < 0.01). When the thigh and calf in the LE were individually studied, subcutaneous echogenicity (p < 0.05), indicating subcutaneous inflammation/fibrosis, and subcutaneous thickness (p < 0.01) also seemed to affect skin hardness, respectively. Conclusions: The skin hardness sensed in the LE seemed to be affected predominantly by dermal thickening. In addition, the pathological changes in the subcutaneous tissue caused by LE seemed to have an impact on skin hardness. Clinical Trial Registration number 2020-150.

Crosstalk Between microRNAs and the Pathological Features of Secondary Lymphedema

Secondary lymphedema is characterized by lymphatic fluid retention and subsequent tissue swelling in one or both limbs that can lead to decreased quality of life. It often arises after loss, obstruction, or blockage of lymphatic vessels due to multifactorial modalities, such as lymphatic insults after surgery, immune system dysfunction, deposition of fat that compresses the lymphatic capillaries, fibrosis, and inflammation. Although secondary lymphedema is often associated with breast cancer, the condition can occur in patients with any type of cancer that requires lymphadenectomy such as gynecological, genitourinary, or head and neck cancers. MicroRNAs demonstrate pivotal roles in regulating gene expression in biological processes such as lymphangiogenesis, angiogenesis, modulation of the immune system, and oxidative stress. MicroRNA profiling has led to the discovery of the molecular mechanisms involved in the pathophysiology of auto-immune, inflammation-related, and metabolic diseases. Although the role of microRNAs in regulating secondary lymphedema is yet to be elucidated, the crosstalk between microRNAs and molecular factors involved in the pathological features of lymphedema, such as skin fibrosis, inflammation, immune dysregulation, and aberrant lipid metabolism have been demonstrated in several studies. MicroRNAs have the potential to serve as biomarkers for diseases and elucidation of their roles in lymphedema can provide a better understanding or new insights of the mechanisms underlying this debilitating condition.

Quantifying Neck Fibrosis and Its Functional Implications: Development of the Neck Fibrosis Scale

OBJECTIVE

Despite increasing recognition of the importance of functional outcomes for patients with head and neck cancer, post-treatment neck fibrosis remains poorly understood. We sought to develop and validate a patient reported outcome measure for head and neck cancer patients with neck fibrosis.

STUDY DESIGN

Prospective multiphase cross-sectional study.

METHODS

To guide instrument development, we employed the World Health Organization International Classification of Functioning, Disability and Health as our conceptual framework. Items were generated using a composite strategy consisting of patient focus groups, literature review, and expert opinion from a multidisciplinary group. Candidate items were reduced through the item impact method. Preliminary psychometric properties of the finalized instrument were evaluated through measures of internal consistency, test-retest reliability, and construct validity.

RESULTS

Four in person focus groups were held with 13 head and neck cancer patients. The process of item generation led to 221 relevant citations and 68 unique items. An additional 17 items were identified from review of existing neck disability questionnaires and expert opinion. A draft instrument with 25 candidate items was generated and reduced to its final 15-item scale using item impact method. Early psychometric testing revealed excellent internal consistency (Cronbach's alpha = 0.95) and test-retest reliability [ICC = 0.95]. Internal consistency at the item level was good (>0.7) for 11/15 individual items. Four separate constructs were evaluated. Three of the four constructs matched our a priori hypotheses.

CONCLUSION

The Neck Fibrosis Scale demonstrates preliminary reliability and validity for discriminate use. Further research is needed to confirm dimensionality and assess responsiveness.

LEVEL OF EVIDENCE

NA Laryngoscope, 2021.

Creation of a rat lymphedema model using extensive lymph node dissection and circumferential soft tissue resection: Is this a reliable model?

INTRODUCTION

The medical demand for lymphedema treatment is huge since the disease mechanism remains unclear, and management are difficult. Our purpose was to develop a reliable lymphedema model mimicking the clinical scenario and allows a microsurgical approach.

MATERIALS AND METHODS

Male Lewis rats weighing 400 to 450 g were used to create lymphedema with groin and popliteal lymph node dissection and creation of 5 mm circumferential skin defect (n = 6). A skin incision was made and closed primarily for control group (n = 5). Evaluation included indocyanine green (ICG) lymphangiography 1 and 2 months postoperatively, volume difference between bilateral hindlimbs measured using micro-CT, and the skin was harvested for histological evaluation 2 months postoperatively.

RESULTS

Larger volume differences present in the lymphedema group (17.50 ± 7.76 vs. 3.73 ± 2.66%, p < .05). ICG lymphangiography indicated dermal backflow only in the lymphedema group. Increased thickness of the epidermis was noted in lymphedema group (28.50 ± 12.61 μm vs. 15.10 ± 5.41 μm, p < .0001). More CD45+ (35.6 ± 26.68 vs. 2.8 ± 4.23 cells/high power field [HPF], p < .0001), CD3+ (38.39 ± 20.17 vs. 9.73 ± 8.62 cells/HPF, p < .0001), and CD4+ cell infiltration (11.7 ± 7.71 vs. 2.0 ± 2.67 cells/HPF, p < .0001) were observed in the lymphedema group. Collagen type I deposition was more in the lymphedema group (0.15 ± 0.06 vs. 0.07 ± 0.03, p < .0005).

CONCLUSIONS

A rat lymphedema model was successfully established. The model can be applied in lymphedema related research.

Nighttime compression supports improved self-management of breast cancer-related lymphedema: A multicenter randomized controlled trial

BACKGROUND

Lymphedema is a prevalent long-term effect of breast cancer treatment associated with reduced quality of life. This study examined the efficacy of nighttime compression as a self-management strategy for women with chronic breast cancer-related lymphedema.

METHODS

Th authors conducted a parallel 3-arm, multicenter, randomized trial. Women were recruited from 3 centers in Canada and randomized to group 1 (daytime compression garment alone [standard care]), group 2 (daytime compression garment plus nighttime compression bandaging), or group 3 (daytime compression garment plus the use of a nighttime compression system garment). The primary outcome was the change in excess arm volume from the baseline to 12 weeks. Participants from all groups used a nighttime compression system garment from weeks 13 to 24.

RESULTS

One hundred twenty women were enrolled, 118 completed the randomized trial, and 114 completed the 24-week follow-up. The rates of adherence to nighttime compression were 95% ± 15% and 96% ± 11% in the compression bandaging and nighttime compression system groups, respectively. After the intervention, the addition of nighttime compression was found to be superior to standard care for both absolute milliliter reductions (P = .006) and percentage reductions (P = .002) in excess arm lymphedema volume. Significant within-group changes were seen for quality of life across all groups; however, no between-group differences were found (P > .05).

CONCLUSIONS

The trial demonstrated a significant improvement in arm lymphedema volume from the addition of nighttime compression whether through the application of compression bandaging or through the use of a nighttime compression system garment.

LAY SUMMARY

Lymphedema is swelling that occurs in the arm on the side of the surgery for breast cancer. Lymphedema occurs in approximately 21% of women. Lymphedema tends to worsen over time and can result in recurrent infections in the arm, functional impairment, and pain. Currently, treatment consists of intensive treatments to reduce the swelling followed by regular use of a compression sleeve during the day. This study examined and found a benefit from the addition of nighttime compression (whether through self-applied compression bandaging or through the use of a nighttime compression system garment) to the use of a daytime compression sleeve.

Biochemical and mechanical signals in the lymphatic vasculature

Lymphatic vasculature is an integral part of the cardiovascular system where it maintains interstitial fluid balance. Additionally, lymphatic vasculature regulates lipid assimilation and inflammatory response. Lymphatic vasculature is composed of lymphatic capillaries, collecting lymphatic vessels and valves that function in synergy to absorb and transport fluid against gravitational and pressure gradients. Defects in lymphatic vessels or valves leads to fluid accumulation in tissues (lymphedema), chylous ascites, chylothorax, metabolic disorders and inflammation. The past three decades of research has identified numerous molecules that are necessary for the stepwise development of lymphatic vasculature. However, approaches to treat lymphatic disorders are still limited to massages and compression bandages. Hence, better understanding of the mechanisms that regulate lymphatic vascular development and function is urgently needed to develop efficient therapies. Recent research has linked mechanical signals such as shear stress and matrix stiffness with biochemical pathways that regulate lymphatic vessel growth, patterning and maturation and valve formation. The goal of this review article is to highlight these innovative developments and speculate on unanswered questions.

Homeostatic maintenance of the lymphatic vasculature

The lymphatic vasculature is emerging as a multifaceted regulator of tissue homeostasis and regeneration. Lymphatic vessels drain fluid, macromolecules, and immune cells from peripheral tissues to lymph nodes (LNs) and the systemic circulation. Their recently uncovered functions extend beyond drainage and include direct modulation of adaptive immunity and paracrine regulation of organ growth. The developmental mechanisms controlling lymphatic vessel growth have been described with increasing precision. It is less clear how the essential functional features of lymphatic vessels are established and maintained. We discuss the mechanisms that maintain lymphatic vessel integrity in adult tissues and control vessel repair and regeneration. This knowledge is crucial for understanding the pathological vessel changes that contribute to disease, and provides an opportunity for therapy development.

Patient-specific surgical options for breast cancer-related lymphedema: technical tips

In order to provide a physiological solution for patients with breast cancer-related lymphedema (BCRL), the surgeon must understand where and how the pathology of lymphedema occurred. Based on each patient's pathology, the treatment plan should be carefully decided and individualized. At the authors' institution, the treatment plan is made individually based on each patient's symptoms and relative factors. Most early-stage patients first undergo decongestive therapy and then, depending on the efficacy of the treatment, a surgical approach is suggested. If the patient is indicated for surgery, all the points of lymphatic flow obstruction are carefully examined. Thus a BCRL patient can be considered for lymphaticovenous anastomosis (LVA), a lymph node flap, scar resection, or a combination thereof. LVA targets ectatic superficial collecting lymphatics, which are located within the deep fat layer, and preoperative mapping using ultrasonography is critical. If there is contracture on the axilla, axillary scar removal is indicated to relieve the vein pressure and allow better drainage. Furthermore, removing the scars and reconstructing the fat layer will allow a better chance for the lymphatics to regenerate. After complete removal of scar tissue, a regional fat flap or a superficial circumflex iliac artery perforator flap with lymph node transfer is performed. By deciding the surgical planning for BCRL based on each patient's pathophysiology, optimal outcomes can be achieved. Depending on each patient's pathophysiology, LVA, scar removal, vascularized lymph node transfer with a sufficient adipocutaneous flap, and simultaneous breast reconstruction should be planned.

Improvement of Limb Volumes after Bariatric Surgery in Nine End-Stage Primary, Secondary, and Obesity-Induced Lymphedema Patients: A Multiple Case Report

Background: Lymphedema (LE) is a chronic condition of swelling due to lymphatic impairment and is characterized by edema and fibro-adipose tissue deposition. LE may be caused by an anomalous development of the lymphatic system, known as primary LE, or may develop secondary to traumatic, infectious, or other external events. Knowledge is increasing about the plural and bidirectional relationship between LE and obesity. The rate of obesity is increasing worldwide, and bariatric surgery offers the most effective and durable treatment, as this surgery exhibits positive effects on many obesity-related diseases. We explored whether bariatric surgery could improve leg volumes in morbidly obese LE patients. Patients: Between 2013 and 2019, 829 patients were hospitalized in our Center of Expertise for Lymphovascular Medicine for intensive treatment of their LE. Nine patients with end-stage primary, secondary, or obesity-induced LE underwent a bariatric procedure related to their morbid obesity. Methods and Results: Data concerning age, gender, medical diagnosis, LE stage, type of bariatric treatment, body weight, body mass index (BMI), and limb volumes were retrospectively collected from the patient files. At the individual patient level, body weight, BMI, leg volumes, and their percent reduction between presurgery and postsurgery were calculated. At the group level, paired sample t-tests were conducted to compare the mean body weight, BMI, and volumes of both legs between postsurgery and presurgery. The data demonstrate a significant decrease in body weight, BMI, and leg volumes in morbidly obese end-stage primary, secondary, and obesity-induced LE patients following bariatric surgery. Conclusions: Our multiple case study indicates that bariatric surgery provides a good indication for concomitant treatment of morbid obesity and LE.

Lymphödem, Inflammation und neue Therapieansätze

Der fehlende Abtransport eiweißreicher interstitieller Flüssigkeit führt zu den bekannten klinischen Zeichen der Lymphödems an der Haut, die im Wesentlichen durch eine Fibrosierung ausgelöst werden. Bisher basiert die Therapie auf der mechanischen Anregung des Lymphtransports durch die komplexe physikalische Entstauung (KPE) oder operativen Maßnahmen, um das Ödem zu reduzieren. Der komplexe Ablauf der Entzündungsvorgänge im Gewebe wurde in den vergangenen Jahren untersucht und zeigt die zentrale Bedeutung von T-Lymphozyten, Makrophagen, LTB4 und diversen Zytokinen. Ausgehend von diesen Erkenntnissen gibt es Erfolg versprechende Therapieansätze mit Ketoprofen, Hydroxytyrosol und weiteren Immunmodulatoren.

A Murine Tail Lymphedema Model

Lymphedema is extremity swelling caused by lymphatic dysfunction. The affected limb enlarges because of accumulation of fluid, adipose, and fibrosis. There is no cure for this disease. A mouse tail model that uses a focal full thickness skin excision near the base of the tail, resulting in tail swelling, has been used to study lymphedema. However, this model may result in vascular comprise and consequent tail necrosis and early tail swelling resolution, limiting its clinical translatability. The chronic murine tail lymphedema model induces sustained lymphedema over 15 weeks and a reliable perfusion to the tail. Enhancements of the traditional murine tail lymphedema model include 1) precise full thickness excision and lymphatic clipping using a surgical microscope, 2) confirmation of post-operative arterial and venous perfusion using high resolution laser speckle, and 3) functional assessment using indocyanine green near infrared laser lymphangiography. We also use tissue nanotransfection technology (TNT) for novel non-viral, transcutaneous, focal delivery of genetic cargo to the mouse tail vasculature.

Prevelance of upper extremity lymphedema and risk factors in patients with mastectomy: Single-center, observational, cross-sectional study

Objective:

Upper extremity complaints are frequently encountered in breast cancer. It was aimed to investigate the pain, extremity pain, and limitation of motion, lymphedema prevalence, severity, risk factors and quality of life in patients with breast cancer followed by mastectomy in our center.

Materials and Methods:

The study included 67 patients with mastectomy. The presence of lymphedema, lymphedema duration, and grade of lymphedema were recorded. Grip strength was measured on both hands using a dynamometer; arm, shoulder and hand problems were evaluated using the disabilities of the arm, shoulder, and hand. Quality of life was assessed using the World Health Organization Quality of Life scale-short form.

Results:

The presence of lymphedema was 23.9%; the most common was international society of lymphology grade 1 (76.1%); the median lymphedema duration was 12 (range, 3-72) months. Radical/modified radical mastectomy (58.2%) was the most common type of surgery. Median pain score in the affected extremity according to the visual analogue scale was 2 (minimum: 0/maximum: 7); the presence of shoulder pain was 40.3%; shoulder movement limitation was 7.5%.

Conclusion:

It was found that lymphedema had a negative effect on quality of life by affecting shoulder, arm, and hand functions even in the early stages. The recognition of risk factors and signs of upper extremity complications in breast cancer survivors will contribute to rehabilitation success.

Refinement and Validation of the Head and Neck Lymphedema and Fibrosis Symptom Inventory

PURPOSE

Lymphedema and fibrosis (LEF) are common yet overlooked late effects of head and neck cancer and its therapy. Lack of reliable and valid measures of head and neck LEF is a critical barrier to the timely identification and management of head and neck LEF. To fill this gap, we developed and pilot tested a 64-item patient-reported outcome measure ( Lymphedema Symptom Intensity and Distress Survey-Head and Neck, LSIDS-H&N). This article aims to report the process of further validation and refinement of the tool.

METHODS AND MATERIALS

A prospective, longitudinal study was conducted, and 120 patients with oral cavity and oropharyngeal cancer were recruited. Participants completed the LSIDS-H&N at pretreatment, end of treatment, and every 3 months up to 12 months after treatment. SAS PROC VARCLUS was used to generate preliminary clusters of item responses. Internal consistency of the item responses within each cluster was assessed using Cronbach's alpha.

RESULTS

A total of 117 patients completed the study. The participants reported that the LSIDS-H&N was easy to understand and captured their symptoms and medical conditions. However, >50% of participants indicated that the survey was burdensome due to length. Thus, we proceeded with item reduction, and the shortened tool (33-item) was named Head and Neck Lymphedema and Fibrosis Symptom Inventory (HN-LEF Symptom Inventory). The subsequent exploration of symptom clusters identified 7 symptom domain clusters (eg, soft tissue and neurologic toxicity), all of which demonstrated good internal consistency.

CONCLUSIONS

The HN-LEF Symptom Inventory has been carefully developed and refined to allow clinicians and researchers to capture LEF-associated symptom burden and function impairments. Additional rigorous psychometric testing of the tool is ongoing to further validate the strength and internal validity of this tool.

S1PR1 regulates the quiescence of lymphatic vessels by inhibiting laminar shear stress-dependent VEGF-C signaling

During the growth of lymphatic vessels (lymphangiogenesis), lymphatic endothelial cells (LECs) at the growing front sprout by forming filopodia. Those tip cells are not exposed to circulating lymph, as they are not lumenized. In contrast, LECs that trail the growing front are exposed to shear stress, become quiescent, and remodel into stable vessels. The mechanisms that coordinate the opposed activities of lymphatic sprouting and maturation remain poorly understood. Here, we show that the canonical tip cell marker Delta-like 4 (DLL4) promotes sprouting lymphangiogenesis by enhancing VEGF-C/VEGF receptor 3 (VEGFR3) signaling. However, in lumenized lymphatic vessels, laminar shear stress (LSS) inhibits the expression of DLL4, as well as additional tip cell markers. Paradoxically, LSS also upregulates VEGF-C/VEGFR3 signaling in LECs, but sphingosine 1-phosphate receptor 1 (S1PR1) activity antagonizes LSS-mediated VEGF-C signaling to promote lymphatic vascular quiescence. Correspondingly, S1pr1 loss in LECs induced lymphatic vascular hypersprouting and hyperbranching, which could be rescued by reducing Vegfr3 gene dosage in vivo. In addition, S1PR1 regulates lymphatic vessel maturation by inhibiting RhoA activity to promote membrane localization of the tight junction molecule claudin-5. Our findings suggest a potentially new paradigm in which LSS induces quiescence and promotes the survival of LECs by downregulating DLL4 and enhancing VEGF-C signaling, respectively. S1PR1 dampens LSS/VEGF-C signaling, thereby preventing sprouting from quiescent lymphatic vessels. These results also highlight the distinct roles that S1PR1 and DLL4 play in LECs when compared with their known roles in the blood vasculature.