Lymphatic Research Articles

Abstract P4-11-18: Arm lymphatic pulsing changes after mastectomy or breast-conserving surgery with axillary lymph node dissection, detected with near-infrared fluorescence lymphatic imaging

Abstract Introduction: Axillary lymph node dissection (ALND) that accompanies mastectomy or breast-conserving surgery is assumed to disrupt arm lymphatic fluid pumping that normally flows in a one-way, distal-to-proximal path to transit cellular waste, immune cells, and large molecules to the thorax. Any resulting stagnation of lymph is surmised to drive the development of lymphedema (LE), with potential lifelong, detrimental effects on quality of life for breast cancer survivors, yet the majority of breast cancer survivors receiving ALND never encounter LE. To date, no objective before-and-after-ALND lymphatic pumping data has been published. Methods: In a prospective, ongoing, longitudinal clinical study (NCT02949726) of breast cancer patients undergoing neoadjuvant chemotherapy, axillary lymph node dissection (ALND) with mastectomy or breast-conserving surgery, and radiation treatment (RT), we used near-infrared fluorescence lymphatic imaging (NIRF-LI) to observe changes in arm lymphatics anatomy and pulsing. NIRF-LI, using a custom-built imaging system, with indocyanine green (ICG) contrast, allows “see through the skin” visualization of arm lymph pumping through lymphatic vessels, and captured videos of 58 locally advanced breast cancer patients before and approximately four weeks after mastectomy or breast-conserving surgery with ALND. Lymphatic pumping frequencies (pulses per minute) were determined from fluorescence intensity fluctuations through regions of interest (ROIs) along lymphatic vessels, quantitated with ImageJ (NIH) free software. Ipsilateral and contralateral arm dorsal, ventral, and axillary-feeding (ventral upper arm) vessel pulsing was classified as 1) static or improved to normal range (improved), or 2) transitioning to abnormal ranges (worsened) after surgery. The number of vessels in each category were tallied and reported herein. Results: After ALND, arm lymphatic pulsing frequencies improved or worsened as shown in Table 1. Conclusions: NIRF-LI allowed objective quantitation of arm lymphatic pumping frequencies captured before and after ALND accompanying mastectomy or breast-conserving surgery for breast cancer. Pulsing frequencies in detectable vessels improved in more axilla-feeding vessels, surprisingly, but worsened or did not change in more ipsilateral and ventral vessels, on both ipsilateral and contralateral sides. While cancer surgery with ALND may be associated with increased risk of BCRL, other factors, such as neoadjuvant chemotherapy, cancer severity, and radiation treatment may contribute to LE etiology. Table 1.Anatomical position (arm)# of Vessels Improved# of Vessels WorsenedIpsilateral dorsal6499Ipsilateral ventral73107Ipsilateral axilla-feeding5626Contralateral dorsal97112Contralateral ventral8988Contralateral axilla-feeding10323 Citation Format: Melissa B Aldrich, Meghan E McWain, Wenyaw Chan, John C Rasmussen, Sarah DeSnyder, Eva M Sevick-Muraca, Simona F Shaitelman. Arm lymphatic pulsing changes after mastectomy or breast-conserving surgery with axillary lymph node dissection, detected with near-infrared fluorescence lymphatic imaging [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-11-18.

Use of ascites CEA as a predictive value for distant metastasis in high-risk stage II and III colorectal cancer.

164 Background: Adjuvant chemotherapy in patients with high-risk stage II and III colorectal cancer prevents recurrence by eliminating minimal residual disease. However, patients who are at high risk of recurrence after completing standard adjuvant therapy are currently unknown. Although ascites CEA level has been associated with long-term oncologic outcomes, the clinical significance of ascites CEA in high-risk stage II and stage III colorectal cancer (CRC) has not yet been described. The present study aimed to determine the long-term oncologic impacts of ascites CEA level after curative colorectal cancer. Methods: A total of 191 patients with stage II/III CRC were included in this study, between January 2015 and December 2018. CEA of peritoneal fluid sampled at the beginning of each operation was analyzed. long-term oncologic outcomes were analyzed with the known risk factors for recurrence in CRC. Results: Multivariate analysis of recurrence revealed that lymphatic invasion (HR 6.0, 95% CI 1.1–32.0, p = 0.04), vascular invasion (HR 2.9, 95%CI 1.0–8.0, p = 0.04), mucinous cancer (HR 5.5, 95% CI 1.6–18.4, p = 0.006), and peritoneal fluid CEA above 5 ng/dl (OR 4.2, 95% CI 1.2–15.0, p = 0.008) were significant risk factors (Table). Peritoneal fluid cytology, microsatellite instability, cancer obstruction did not significantly impact DFS in stage II/III CRC. There were 14 patients with liver metastasis, among them, 11 patients without peritoneal metastasis; they had high ascites CEA level. While 8 patients had lung metastasis, 7 of them confirmed high ascites CEA levels. Conclusions: Our results indicate that the ascites CEA may predict as an important biomarker to identify those at risk of distant metastasis in high-risk stage II and stage III CRC patients. We suggest ascites CEA analysis might be included in patient risk assessments and oncologic prediction tools.

Multilayer microfluidic platform for the study of luminal, transmural, and interstitial flow

Efficient delivery of oxygen and nutrients to tissues requires an intricate balance of blood, lymphatic, and interstitial fluid pressures (IFPs), and gradients in fluid pressure drive the flow of blood, lymph, and interstitial fluid through tissues. While specific fluid mechanical stimuli, such as wall shear stress, have been shown to modulate cellular signaling pathways along with gene and protein expression patterns, an understanding of the key signals imparted by flowing fluid and how these signals are integrated across multiple cells and cell types in native tissues is incomplete due to limitations with current assays. Here, we introduce a multi-layer microfluidic platform (MμLTI-Flow) that enables the culture of engineered blood and lymphatic microvessels and independent control of blood, lymphatic, and IFPs. Using optical microscopy methods to measure fluid velocity for applied input pressures, we demonstrate varying rates of interstitial fluid flow as a function of blood, lymphatic, and interstitial pressure, consistent with computational fluid dynamics (CFD) models. The resulting microfluidic and computational platforms will provide for analysis of key fluid mechanical parameters and cellular mechanisms that contribute to diseases in which fluid imbalances play a role in progression, including lymphedema and solid cancer.

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.

Lymphedema and Obesity.

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

Lymphatic Collecting Vessels in Health and Disease: A Review of Histopathological Modifications in Lymphedema.

Secondary lymphedema of the extremities affects millions of people in the world as a common side effect of oncological treatments with heavy impact on every day life of patients and on the health care system. One of the surgical techniques for lymphedema treatment is the creation of a local connection between lymphatic vessels and veins, facilitating drainage of lymphatic fluid into the circulatory system. Successful results, however, rely on using a functional vessel for the anastomosis, and vessel function, in turn, depends on its structure. The structure of lymphatic collecting vessels changes with the progression of lymphedema. They appear initially dilated by excess interstitial fluid entered at capillary level. The number of lymphatic smooth muscle cells in their media then increases in the attempt to overcome the impaired drainage. When lymphatic muscle cells hyperplasia occurs at the expenses of the lumen, vessel patency decreases hampering lymph flow. Finally, collagen fiber accumulation leads to complete occlusion of the lumen rendering the vessel unfit to conduct lymph. Different types of vessels may coexist in the same patient but usually the distal part of the limb contains less affected vessels that are more likely to perform efficient lymphatic–venular anastomosis. Here we review the structure of the lymphatic collecting vessels in health and in lymphedema, focusing on the histopathological changes of the lymphatic vessel wall based on the observations on segments of the vessels used for lymphatic–venular anastomoses.

Non-invasive MR imaging of human brain lymphatic networks with connections to cervical lymph nodes

Meningeal lymphatic vessels have been described in animal studies, but limited comparable data is available in human studies. Here we show dural lymphatic structures along the dural venous sinuses in dorsal regions and along cranial nerves in the ventral regions in the human brain. 3D T2-Fluid Attenuated Inversion Recovery magnetic resonance imaging relies on internal signals of protein rich lymphatic fluid rather than contrast media and is used in the present study to visualize the major human dural lymphatic structures. Moreover we detect direct connections between lymphatic fluid channels along the cranial nerves and vascular structures and the cervical lymph nodes. We also identify age-related cervical lymph node atrophy and thickening of lymphatics channels in both dorsal and ventral regions, findings which reflect the reduced lymphatic output of the aged brain.

All Edema Is Lymphedema: Progressing Lymphedema and Wound Management to an Integrated Model of Care

BACKGROUND: Chronic edema affects millions of people in the United States and worldwide. Edema can result from a variety of diseases, trauma, medications, and other contributing factors; however, all edema is related to lymphatic fluid dysregulation. Additionally, lymphatic impairment and integumentary dysfunction are interrelated, leading to complex clinical presentations that require an integrated medical model of care to maximize outcomes. PURPOSE: This narrative review article will highlight the current evidence that details lymphatic physiology, fluid regulation by the endothelial glycocalyx layer, and the interconnectedness of the vascular and integumentary systems leading to a paradigm shift in our understanding of edema, lymphedema, and chronic wounds. Traditional pedagogy remains siloed with respect to the body systems, whereas current evidence indicates a certain interdependence, particularly between and among the venous, lymphatic, and integumentary systems. METHODS: Comprehensive narrative review of the current and past literature (2010–2021 through PubMed, Google Scholar, MEDLINE Complete, UpToDate) focusing on lymphatic physiology, fluid regulation, the endothelial glycocalyx layer, lymphedema, and venous insufficiency. Review focuses on new evidence supporting the interconnectedness of the systems to support a unified medical management approach. RESULTS: All edema is related to lymphatic dysfunction, whether transient or permanent, thereby creating a lymphedema continuum. Further, lymphatic impairment creates cutaneous regions of skin barrier failure, rendering the skin more susceptible to breakdown and chronic wounds. CONCLUSION: A synthesis of the current evidence suggests an interconnected relationship of the lymphatic, venous, and integumentary systems, highlighting the need for a more integrated medical model of care to provide efficient and comprehensive care and improve patient outcomes.

Improving Venous Ulcer Outcomes

Venous leg ulcers (VLUs) are caused by compromised flow of venous and lymphatic fluids from the lower leg toward the central circulatory system. They are one of the most common types of chronic wounds, affecting 3% to 5% of those 65 years of age and older.¹ Most VLUs heal within 12 weeks with sustained lower leg compression sufficient to reduce the edema associated with venous insufficiency.² Diagnosing and improving a patient's venous insufficiency and addressing concomitant arterial disease are key elements of VLU management.³ Surgical correction has been effective for superficial venous insufficiency.⁴ Various topical,⁵ physical,⁶ or systemic⁷ interventions have been studied as adjuncts to compression in efforts to further improve VLU outcomes, with mixed results. This month's Evidence Corner summarizes recent randomized clinical trials (RCTs) documenting healing effects of topical gauze dressings impregnated with hyaluronic acid (HA) or placebo cream⁸ as an adjunct to patient-appropriate compression or low-level laser radiation as an adjunct to clinically prescribed elastic compression, diet, leg elevation, exercise, and moisture-retentive, absorbent, or microbicidal dressings.⁸.

Dynamic study of tip-link tension and stereocilia motion in cochlea

Explanation of cochlear active acoustic amplification mechanism has been an unsolved medical problem. This mechanism is closely related to the motion of the stereocilia at the top of the outer hair cells in the cochlea. The motion of stereocilia is regulated by the tip-link tension and the fluid force of the lymph fluid. Therefore, studying the tip-link tension during the motion of stereocilia is an important part of the explanation of the cochlea's active sensory sound amplification mechanism. Most of previous studies regarded the stereocilia as rigid bodies, and ignored the influence of shaft bending when studying the mechanical properties of hair bundle. Most of the researches on elastic stereocilia used the finite element simulation, or simplified the model by ignoring the fluid-solid coupling with lymph fluid, or considered only static loading. Based on the Poiseuille flow combined with the distributed parameter model, the analytical solution of the elastic motion of stereocilia is derived in this work. The dynamic response of the stereocilia under the shear force of the tectorial membrane and the change law of tip-link tension are studied. The shaft bending produces a nonlinear accumulation of displacement at the height of the stereocilia. The higher the stereocilia, the more obvious the accumulation effect is. Under the action of dynamic load, the shaft bending contributes most to the displacement response in the tall stereocilium, and this contribution is easily affected by frequency change. Under low frequency load, the displacement response of tall stereocilium comes mainly from the root deflection. At high frequency, the shaft bending increases significantly, and the displacement response is produced by the combination of shaft bending and root deflection. The change of F-actin content in the cochlea exposed to noise would affect the stereocilia stiffness. In this paper, it is found that the decrease of stereociliary Young's modulus will increase the peak value of normalized tension and reduce its peak frequency, and the amplitude of normalized tension will increase under the low frequency shear load. Since the tip-link is connected to an ion channel, the change of normalized tension will affect the probability of ion channels opening, change the ability of cochlea to perceive the sound of corresponding frequency, and then affect the frequency selectivity of hair bundle. Therefore, previous studies of stereocilia regarded as rigid bodies underestimated the response of the cochlea to low-frequency acoustic signals. This model accurately describes the law of tip-link tension and provides a corresponding theoretical explanation for hearing impairment caused by noise environment. Previous experiments have shown that the lymphatic viscous resistance has little effect on the deflection of stereocilia. In this paper, when the viscous resistance is ignored, the tip-link tension changes very little, and when the pressure between the stereocilia is ignored, the tip-link tension changes significantly and the resonance peak of <inline-formula><tex-math id="M4">\begin{document}$ {f_2} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="4-20211105_M4.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="4-20211105_M4.png"/></alternatives></inline-formula> disappears. Therefore, lymphatic fluid regulates the resonance properties of the tip-link tension by creating the pressure between the stereocilia. The presence of lymphatics is essential for generating the frequency characteristics of the hair bundle. In the low frequency domain, the motion of stereocilia is regulated mainly by tip-link, and in the high frequency domain, it is regulated mainly by lymphatic pressure.

Postoperative chylothorax and left internal jugular vein thrombus after complex cyanotic heart disease surgery

Chylothorax is the accumulation of lymphatic fluid in pleural space following traumatic injury to lymphatic vessels, systemic venous obstruction, dysfunction of the right ventricle, thrombosis of the duct, superior vena cava or subclavian vein, or postoperatively. A 2 ½-year-old male child operated for transposition of great arteries (TGA), tricuspid atresia (TA), and hypoplastic right ventricle 15 days ago developed chylothorax and left internal jugular vein thrombus. The child was initially managed conservatively with nutritional management, anticoagulation, and octreotide followed by interventional radiological management with lipoidol injection. Early suspicion and diagnosis are crucial. The management was difficult owing to a lack of proper guidelines. Further research is warranted.

Simulated Lymphatic Fluid for In-Vitro Assessment in Pharmaceutical Development

Simulated Lymphatic Fluid for In-Vitro Assessment in Pharmaceutical Development

Transport and lymphatic uptake of monoclonal antibodies after subcutaneous injection.

The subcutaneous injection has emerged to become a feasible self-administration practice for biotherapeutics due to the patient comfort and cost-effectiveness. However, the available knowledge about transport and absorption of these agents after subcutaneous injection is limited. Here, a mathematical framework to study the subcutaneous drug delivery of mAbs from injection to lymphatic uptake is presented. A three-dimensional poroelastic model is exploited to find the biomechanical response of the tissue by taking into account tissue deformation during the injection. The results show that including tissue deformability noticeably changes tissue poromechanical response due to the significant dependence of interstitial pressure on the tissue deformation. Moreover, the importance of the amount of lymph fluid at the injection site and the injection rate on the drug uptake to lymphatic capillaries is highlighted. Finally, variability of lymphatic uptake due to uncertainty in parameters including tissue poromechanical and lymphatic absorption parameters is evaluated. It is found that interstitial pressure due to injection is the major contributing factor in short-term lymphatic absorption, while the amount of lymph fluid at the site of injection determines the long-term absorption of the drug. Finally, it is shown that the lymphatic uptake results are consistent with experimental data available in the literature.

Application of Photoacoustic Imaging for Lymphedema Treatment

Background Lymphatic vessels are difficult to identify using existing modalities as because of their small diameter and the transparency of the lymph fluid flowing through them. Methods Here, we introduce photoacoustic lymphangiography (PAL), a new modality widely used for lymphedema treatment, to observe limb lymphatic vessels. The photoacoustic imaging system used in this study can simultaneously visualize lymphatic vessels and veins with a high resolution (0.2 mm) and can also observe their three-dimensional relationship with each other. Results High-resolution images of the lymphatic vessels, detailed structure of the dermal back flow, and the three-dimensional positional relationship between the lymphatic vessels and veins were observed by PAL. Conclusion The clear image provided by PAL could have a major application in pre- and postoperative use during lymphaticovenular anastomosis for lymphedema treatment.

Multichromatic near-infrared imaging to assess interstitial lymphatic and venous uptake in vivo.

.Significance: Changes in interstitial fluid clearance are implicated in many diseases. Using near-infrared (NIR) imaging with properly sized tracers could enhance our understanding of how venous and lymphatic drainage are involved in disease progression or enhance drug delivery strategies.Aim: We investigated multichromatic NIR imaging with multiple tracers to assess in vivo microvascular clearance kinetics and pathways in different tissue spaces.Approach: We used a chemically inert IR Dye 800CW (D800) to target venous capillaries and a purified conjugate of IR dye 680RD with 40 kDa PEG (P40D680) to target lymphatic capillaries in vivo. Optical imaging settings were validated and tuned in vitro using tissue phantoms. We investigated multichromatic NIR imaging’s utility in two in vivo tissue beds: the mouse tail and rat knee joint. We then tested the ability of the approach to detect interstitial fluid perturbations due to exercise.Results: In an in vitro simulated tissue environment, free dye and PEG mixture allowed for simultaneous detection without interference. In the mouse tail, co-injected NIR tracers cleared from the interstitial space via distinct routes, suggestive of lymphatic and venous uptake mechanisms. In the rat knee, we determined that exercise after injection transiently increased lymphatic drainage as measured by lower normalized intensity immediately after exercise, whereas exercise pre-injection exhibited a transient delay in clearance from the joint.Conclusions: NIR imaging enables simultaneous imaging of lymphatic and venous-mediated fluid clearance with great sensitivity and can be used to measure temporal changes in clearance rates and pathways.

Collective dynamics of gastric cancer cells in fluid.

Gastric cancer (GC) is the most common digestive system malignant cancer, and gastric cancer cells (GCC) can migrate in normal solid tissue and lymphatic fluid. Previously, much research has focused on the migration process when the cells are in the solid condition, such as migration through tissue, adhesion, and invasion processes, while little is known about the migration process of GCC in lymphatic fluid. In the current study, we investigate the migration of GCC in a fluid condition in an in vitro environment. We find that the cells diffuse mainly because of their cell viability. Therefore, despite the fact that lymph fluid is almost quiescent, GCCs can migrate around easily. The dynamics of cells also demonstrate a collective glassy dynamic similar to ordinary inactive glassy materials. As density of the cells increases, the movement of the cells becomes slower, and the collective dynamic becomes heterogeneous, which is similar to the dynamically heterogeneous behavior in glassy materials. The results will help us gain a better knowledge of the characteristics of GCC dynamics in the liquid phase which is crucial for the understanding of the mechanism for lymphatic metastasis. This can also potentially help early diagnosis of lymph node metastasis in GC and provide new insights for future clinical treatment.

Chylous leak following pylorus-preserving gastrectomy with D1 lymphadenectomy for carcinoma stomach: A case report.

Introduction and importanceChyle leak is the leakage of milk-like triglyceride-rich lymphatic fluid from the lymphatic system to the peritoneal cavity. The incidence of chyle leak after radical gastrectomy is very low.Case presentationA 77-year-old female presented with complaints of decreased appetite and weight loss for six months. Upper gastrointestinal endoscopy showed a polypoidal growth along the greater curvature and the histopathological report of the biopsy taken showed high-grade tubular adenoma with high-grade dysplasia. The patient underwent pylorus-preserving gastrectomy with D1 lymphadenectomy. Postoperatively, after initiation of the oral diet, the abdominal drain started draining milky white fluid, which was rich in triglyceride. The patient was managed conservatively with nil per oral, total parenteral nutrition, and somatostatin analogue.Clinical discussionThe appearance of milky, nonpurulent fluid in abdominal drain concurrent with the initiation of oral feeding is characteristic of postoperative chyle leak. In our case, we managed the case successfully over a few days with total parenteral nutrition, nil per oral status, and somatostatin analogue.ConclusionThe incidence of chyle leak after gastrectomy is low, if it occurs it prolongs the hospital stay. Higher age, female gender, and early enteral feeding have been seen as the risk factors for chyle leak. Conservative treatment is effective and is the treatment of choice.

Extracellular vesicles are players of the immune continuum

Regulation of immune responses was among the first functions of extracellular vesicles to be identified, more than twenty years ago. What exactly defines the outcome of an immune response remains a challenging issue. Owing to their reduced size, extracellular vesicles easily diffuse in interstitial and lymphatic fluids, where they can interact with the multiple effectors of the immune system. By accelerating and amplifying immune interactions, these ultra-mobile units may contribute to local and systemic coordination for efficient adaption to external and internal changes. Here we introduce the related ground-breaking studies of extracellular vesicle-mediated immune effects and present ongoing considerations on their potential roles in health and the development of immune disorders.

Reactivate Your Second Heart

Sitting or standing without moving the leg muscles puts additional stress on your heart, as blood and lymph pool in the legs. Tightening and relaxing the calf muscles can prevent the pooling of the blood. The inactivity of the calf muscles does not allow the blood to flow upward and may result in “sitting disease,” contributing to the development of diabetes and cardiovascular disease. Activating the calf muscles as well as other leg muscles are strategies to support cardiovascular health. Thus, the calf muscles are sometimes called “our second heart.” The important function of our “second heart” is to act as a pump to return venous blood and lymph fluids upward, which can occur only when we interrupt sitting with many brief exercises by frequently standing up during the day. Suggestions regarding how to implement short breaks are included. Note that, medically, the term second heart refers to the cisterna chyli, which brings the lymphatic fluids up from the abdomen; however, in this article, second heart is used in a common popular sense of the term as the description of the calf muscle to pump the venous blood toward the heart.

Lymphedema: Common Side Effect.

For lymphedema, standards of care are based on established evidence-based practice. Lymphedema is the accumulation of lymph fluid that obstructs the flow of the lymphatic system, causing persistent swelling of the affected body part. Lymphedema is most commonly seen after lymph node dissection or radiation therapy. It occurs in 10%-40% of patients with breast cancer and 80% of patients with lymph node dissection in the groin.