Nanofibrillar Collagen Scaffold Enhances Edema Reduction and Formation of New Lymphatic Collectors after Lymphedema Surgery

Molecular pathophysiology of secondary lymphedema

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

Biomaterial-based scaffolds for direct in situ programming of tumor-infiltrating T lymphocytes

Adoptive cell therapy with tumor-infiltrating T cells (TILs) has generated exciting clinical trial results for the treatment of unresectable solid tumors. However, solid tumors remain difficult targets for adoptively transferred T cells, due in part to poor migration of TILs to the tumor, physical barriers to infiltration, and active suppression of TILs by the tumor. Furthermore, a highly skilled team is required to obtain tumor tissue, isolate and expand the TILs ex vivo, and reinfuse them into the patient, which drives up costs and limits patient access. Here, we describe a cell-free polymer implant designed to recruit, genetically reprogram and expand host T cells at tumor lesions in situ. Importantly, the scaffold can be fabricated on a large scale and is stable to lyophilization. Using a mouse breast cancer model, we show that the implants quickly and efficiently amass cancer-specific host lymphocytes at the tumor site in quantities sufficient to bring about long-term tumor regression. Given that surgical care is the mainstay of cancer treatment for many patients, this technology could be easily implemented in a clinical setting as an add-on to surgery for solid tumors. Furthermore, the approach could be broadened to recruit and genetically reprogram other therapeutically desirable host cells, such as macrophages, natural killer cells or dendritic cells, potentially boosting the antitumor effectiveness of the implant even more.

Surgical Treatment of Breast Lymphedema: A Distinct Pathology With Unique Challenges

BACKGROUND

Supermicrosurgical advances such as lymphovenous bypass (LVB) have enabled effective physiologic treatment of lymphedema affecting the extremities. Reports of surgical treatment for breast lymphedema (BL) are sparse, consisting of case reports and almost exclusively LVB. We report our experience with BL, including a case of mastectomy and breast reconstruction with abdominal free flap and inguinal vascularized lymph node transfer (VLNT) for BL. We compare our series with the surgical literature to discern unique characteristics and treatment limitations inherent to this disease.

METHODS

A database was prospectively maintained from September 2020 to May 2023 including all patients diagnosed with BL who were referred to our institution. Breast lymphedema was diagnosed using clinical criteria, and relevant patient data were recorded. Patients interested in surgical management underwent indocyanine green lymphography to determine candidacy for LVB or other interventions. All patients, including those surgically managed, were treated with complex decongestive therapy.

RESULTS

Nine patients with BL were included. Eight had undergone breast-conserving therapy for breast cancer with whole breast irradiation. One patient was treated for Hodgkin lymphoma with axillary lymphadenectomy and axillary radiation. Indocyanine green lymphography was performed in 6 patients, of which 4 patients had diffuse dermal backflow. Two patients had lymphatic targets suitable for LVB, including the patient without breast irradiation. Three patients were managed surgically. One patient without bypass targets underwent breast reduction with partial symptomatic relief, later followed by a mastectomy with abdominal free flap reconstruction and VLNT. Two patients with suitable bypass targets underwent LVB, with resolution of breast swelling and subjective symptoms.

CONCLUSIONS

The diffuse lymphatic obliteration due to radiation field effect in BL results in a distinct pathophysiology compared with extremity lymphedema. Although published reports of surgical BL treatment almost exclusively describe LVB, other surgical options may be more frequently required. Ablative strategies such as mastectomy and regenerative techniques such as VLNT should be considered potential first-line treatment options for these patients.

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

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

Biomaterials in the clinical treatment of lymphedema-a systematic review

OBJECTIVE

Lymphedema is a chronic condition caused by impaired lymphatic fluid drainage, resulting in progressive edema. The current mainstay of lymphedema therapy consists of conservative therapy and surgical therapy. In this systematic review, we investigated the novel role of biomaterials in clinical lymphedema therapy and assessed their objective outcomes and the complication rate associated with their use.

METHODS

Studies were identified through systematic review using the Embase and PubMed/MEDLINE databases. Only original articles reporting the use of biomaterials for clinical lymphedema therapy were included. The primary outcome measure was the objective reduction in limb volume after biomaterial use. The secondary outcome measure was the assessment of biomaterial safety.

RESULTS

A total of 354 articles were identified in the first search, of which 10 met our inclusion criteria. These articles described the use of two biomaterials, nanofibrillar collagen scaffolds (NCSs) and silicone tubes (STs), for the treatment of lymphedema. NCS implantation showed an average excess limb volume reduction of 1% to 10.7% and clear evidence of lymphangiogenesis on imaging. No complications were 7documented after NCS implantation. ST implantation showed an average limb volume reduction of 700 to 887 mL and limb circumference reduction of 3.1 to 8 cm in patients with advanced stage lymphedema. Of 177 patients treated with ST implantation, only 11 (6.2%) developed local inflammation.

CONCLUSIONS

Both NCS and ST implantation showed promising limb volume reduction; however, with the scarce literature available, additional research is needed to determine their effectiveness. Both demonstrated good safety profiles, with no complications after NCS implantation and a complication rate equivalent to other similar implants for ST implantation.

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.

Development of a rat model of lymphedema and the implantation of a collagen-based medical device for therapeutic intervention

Secondary lymphedema is a common condition among cancer survivors, and treatment strategies to prevent or treat lymphedema are in high demand. The development of novel strategies to diagnose or treat lymphedema would benefit from a robust experimental animal model of secondary lymphedema. The purpose of this methods paper is to describe and summarize our experience in developing and characterizing a rat hindlimb model of lymphedema. Here we describe a protocol to induce secondary lymphedema that takes advantage of micro computed tomography imaging for limb volume measurements and visualization of lymph drainage with near infrared imaging. To demonstrate the utility of this preclinical model for studying the therapeutic benefit of novel devices, we apply this animal model to test the efficacy of a biomaterials-based implantable medical device.

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.

Diagnosis and Treatment of Post-Prostatectomy Lymphedema: What's New?

Lymphedema is a chronic progressive disorder that significantly compromises patients' quality of life. In Western countries, it often results from cancer treatment, as in the case of post-radical prostatectomy lymphedema, where it can affect up to 20% of patients, with a significant disease burden. Traditionally, diagnosis, assessment of severity, and management of disease have relied on clinical assessment. In this landscape, physical and conservative treatments, including bandages and lymphatic drainage have shown limited results. Recent advances in imaging technology are revolutionizing the approach to this disorder: magnetic resonance imaging has shown satisfactory results in differential diagnosis, quantitative classification of severity, and most appropriate treatment planning. Further innovations in microsurgical techniques, based on the use of indocyanine green to map lymphatic vessels during surgery, have improved the efficacy of secondary LE treatment and led to the development of new surgical approaches. Physiologic surgical interventions, including lymphovenous anastomosis (LVA) and vascularized lymph node transplant (VLNT), are going to face widespread diffusion. A combined approach to microsurgical treatment provides the best results: LVA is effective in promoting lymphatic drainage, bridging VLNT delayed lymphangiogenic and immunological effects in the lymphatic impairment site. Simultaneous VLNT and LVA are safe and effective for patients with both early and advanced stages of post-prostatectomy LE. A new perspective is now represented by the combination of microsurgical treatments with the positioning of nano fibrillar collagen scaffolds (BioBridgeTM) to favor restoring the lymphatic function, allowing for improved and sustained volume reduction. In this narrative review, we proposed an overview of new strategies for diagnosing and treating post-prostatectomy lymphedema to get the most appropriate and successful patient treatment with an overview of the main artificial intelligence applications in the prevention, diagnosis, and management of lymphedema.

Biomedical Applications of Collagen

Extracellular matrix proteins (ECMs) provide structural support and dynamic signaling cues that regulate cell behavior and tissue morphogenesis [...].

Doxycycline for the treatment of breast cancer-related lymphedema

Purpose: Secondary lymphedema is a common complication of cancer treatment for which no effective drug treatments yet exist. Level I clinical data suggests that doxycycline is effective for treating filariasis-induced lymphedema, in which it decreases tissue edema and skin abnormalities; however, this treatment has not been tested for cancer-related lymphedema. Over the past year, we used doxycycline in an off-label manner in patients with breast cancer-related secondary lymphedema. The purpose of this report was to retrospectively analyze the efficacy of this treatment. Methods: Patients who presented to our lymphedema clinic between January 2021 and January 2022 were evaluated, and barring allergies or contraindications to doxycycline treatment, were counseled on the off-label use of this treatment. Patients who wished to proceed were treated with doxycycline (200 mg given orally once daily) for 6 weeks. After IRB approval of this study, lymphedema outcomes were retrospectively reviewed. Results: Seventeen patients with a mean follow-up of 17.0 ± 13.2 weeks were identified in our retrospective review. Although doxycycline treatment had no significant effect on relative limb volume change or L-Dex scores, we found a significant improvement in patient-reported quality of life. Analysis of patient responses to the Lymphedema Life Impact Scale showed a significant improvement in the total impairment score due to improvements in the physical and psychological well-being subscales (p = 0.03, p = 0.03, p = 0.04, respectively). Conclusion: This small, retrospective study did not show significant improvements in limb volume or L-Dex scores in patients with breast cancer-related lymphedema treated with doxycycline. However, our patients reported improvements in quality-of-life measures using a validated lymphedema patient-reported outcome instrument. Our results suggest that doxycycline may be of use in patients with breast cancer-related lymphedema; however, larger and more rigorous studies are needed.

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.

Multimodality Approach to Lymphedema Surgery Achieves and Maintains Normal Limb Volumes: A Treatment Algorithm to Optimize Outcomes

Surgical treatment of advanced lymphedema is challenging and outcomes are suboptimal. Physiologic procedures including lymphaticovenous anastomosis (LVA) and vascularized lymph node transfer (VLNT) improve lymphatic flow but cannot reverse fibrofatty tissue deposition, whereas liposuction removes fibrofatty tissue but cannot prevent disease progression. The adjunctive use of nanofibrillar collagen scaffolds (BioBridge^TM) can promote lymphangiogenesis. We report a treatment algorithm utilizing a multimodality approach to achieve sustained normal limb volumes in patients with stage II-III lymphedema. A retrospective review of late stage II-III lymphedema patients treated with liposuction, physiologic procedures, and BioBridge^TM from 2016 through 2019 was conducted. Treatment outcome in the form of excess volume reduction is reported. Total of 14 patients underwent surgical treatment of late stage II and III lymphedema according to our triple therapy algorithm. Patients had a baseline median volume excess of 29% (19.8, 43.3%). The median volume excess was improved to 0.5% (−4.3, 3.8%) at 14.4 months from the first stage surgery (p < 0.05) and further improved to −1.0% (−3.3, 1.3%) after triple therapy with BB placement at 24.6 months. A triple therapy surgical treatment algorithm can optimize outcomes and achieve sustained normalization of limb volume in late stage II-III lymphedema. The incorporation of nanofibrillar collagen scaffold technology allows for improved and sustained volume reduction.

Adipose tissue-derived microvascular fragments promote lymphangiogenesis in a murine lymphedema model

Chronic lymphedema after cancer treatment is common and there is still no cure for this disease. We herein investigated the lymphangiogenic capacity of adipose tissue-derived microvascular fragments (MVF), which contain stem cells and lymphatic vessel fragments. Secondary lymphedema was induced in the hindlimbs of C57BL/6J mice. Green fluorescence protein (GFP)+ MVF were isolated from transgenic C57BL/6Tg (CAG-EGFP)1Osb/J mice, suspended in collagen hydrogel, and injected in the lymphadenectomy defect of wild-type animals. This crossover model allowed the detection of MVF-derived blood and lymphatic vessels after transplantation. The MVF group was compared with animals receiving collagen hydrogel only or a sham intervention. Lymphangiogenic effects were analyzed using volumetry, magnetic resonance (MR) lymphography, histology, and immunohistochemistry. MVF injection resulted in reduced hindlimb volumes when compared to non-treated controls. MR lymphography revealed lymphatic regeneration with reduced dermal backflow after MVF treatment. Finally, MVF transplantation promoted popliteal angiogenesis and lymphangiogenesis associated with a significantly increased microvessel and lymphatic vessel density. These findings indicate that MVF transplantation represents a promising approach to induce therapeutic lymphangiogenesis.