New Insights into the Pathophysiology of Primary and Secondary Lymphedema: Histopathological Studies on Human Lymphatic Collecting Vessels

Combination of Supramicrosurgical Lymphatico-Venular Anastomosis (sLVA) and Lymph-Sparing Liposuction in Treating Cancer-Related Lymphedema: Rationale for a Regional One-Stage Approach

Objective: Cancer-related lymphedema represents a potential complication of cancer treatment. The aim of this study is to evaluate the effectiveness of the combination of lymphatico-venular anastomosis and liposuction in the treatment of secondary lymphedema. Methods: We present a retrospective analysis of patients affected by cancer-related unilateral limb lymphedema. Inclusion criteria included previous neoplastic pathology with the consequent development of unilateral limb lymphedema, while the exclusion criteria included the presence of comorbidities and the persistence of cancer, as well as previous lymphatic surgery. The outcomes to be included were a reduction in the limb volume and lymphangitis rate, and an improvement in the quality of life. Patients' data were assessed before surgery and 1 year after surgery. Perioperative management included clinical and ultrasonographical evaluations. Under local anesthesia, lymphatico-venular anastomosis with the supramicrosurgical technique and the liposuction of the affected limb was performed in the same surgical session. Results: A total of 24 patients were enrolled in the study. One year after the surgery, an average volume reduction of 37.9% was registered (p = 0.0000000596). The lymphangitis rate decreased after surgery from 4.67 to 0.95 per year (p = 0.000007899). The quality-of-life score improved from 68.7 to 16 according to the LLIS scale. Conclusions: The combination of LVA and liposuction represents a valid strategy for treating cancer-related lymphedema, ensuring stable results over time. In addition, it can be performed under local anesthesia, resulting in being minimally invasive and well-tolerated by patients. This paper reports on the short-term efficacy of this combined technique.

Concordance between preoperative imaging methods in patients with limb lymphedema undergoing supermicrosurgical lymphaticovenular anastomosis

OBJECTIVE

Supermicrosurgical lymphaticovenular anastomosis (LVA) is increasingly being recognized as a first-line treatment of limb lymphedema because it is minimally invasive and highly effective. Lymphoscintigraphy and indocyanine green (ICG) lymphography are the two most commonly performed diagnostic imaging examinations to establish the indication and plan the procedure for patients affected by limb lymphedema. In a small group of patients, the information between these two imaging tools can be discordant, showing different anatomical drainage pathways or the absence of drainage and dermal backflow in one examination and valid drainage pathways in the other. The purpose of this study is to examine the types of possible discrepancies between lymphoscintigraphy of the superficial system and ICG lymphography and to describe the surgical outcomes after LVA for patients presenting with such discrepancies.

METHODS

We retrospectively reviewed the data of all patients who underwent LVA for upper or lower limb lymphedema between July 2015 and July 2023. From this series, we identified a group of patients with nonconcordant imaging results from lymphoscintigraphy and ICG lymphography before lymphatic surgery. Nonconcordant findings were described in terms of "pattern discordance" and "pathway discordance." The surgical outcome was measured by the change in the mean circumference of the limb after surgery. The changes between the preoperative and postoperative limb measures were analyzed using the Student t test. P values < .05 were considered significant.

RESULTS

A total of 28 patients with limb lymphedema exhibited inconsistencies between preoperative lymphoscintigraphy of the superficial system and ICG lymphography. Among these patients, 14 experienced pattern discordance, 13 had pathway discordance, and 1 patient had both. After LVA, we observed a significant reduction in the average circumference of the affected limb in the analyzed group.

CONCLUSIONS

The discrepancy in the information between lymphoscintigraphy and ICG lymphography in the preoperative study of patients affected by limb lymphedema is rare but possible. This phenomenon is still not fully explained; however, our results suggest that it does not correlate with the outcome of supermicrosurgical LVAs.

Surgical Treatment for Primary Lymphedema: A Systematic Review of the Literature

This is a retrospective review of surgical management for primary lymphedema. Data were extracted from 55 articles from PubMed MEDLINE, Web of Science, SCOPUS, and Cochrane Central Register of Controlled Trials between the database inception and December 2022 to evaluate the outcomes of lymphaticovenous anastomosis (LVA) and vascularized lymph node transfer (VLNT), and outcomes of soft tissue extirpative procedures such as suction-assisted lipectomy (SAL) and extensive soft tissue excision. Data from 485 patients were compiled; these were treated with LVA ( n  = 177), VLNT ( n  = 82), SAL ( n  = 102), and excisional procedures ( n  = 124). Improvement of the lower extremity lymphedema index, the quality of life (QoL), and lymphedema symptoms were reported in most studies. LVA and VLNT led to symptomatic relief and improved QoL, reaching up to 90 and 61% average circumference reduction, respectively. Cellulitis reduction was reported in 25 and 40% of LVA and VLNT papers, respectively. The extirpative procedures, used mainly in patients with advanced disease, also led to clinical improvement from the volume reduction, as well as reduced incidence of cellulitis, although with poor cosmetic results; 87.5% of these reports recommended postoperative compression garments. The overall complication rates were 1% for LVA, 13% for VLNT, 11% for SAL, and 46% for extirpative procedures. Altogether, only one paper lacked some kind of improvement. Primary lymphedema is amenable to surgical treatment; the currently performed procedures have effectively improved symptoms and QoL in this population. Complication rates are related to the invasiveness of the chosen procedure.

90Y-/166Ho- 'Radiation lobectomy' for liver tumors induces abnormal morphology and impaired drainage of peritumor lymphatics

Background & Aims

High-dose unilobar radioembolization, or 'radiation lobectomy' (RL), is an induction therapy that achieves contralateral future liver remnant hypertrophy while simultaneously irradiating the tumor. As such, it may prevent further growth, but it is unknown whether RL affects intrahepatic lymphatics, a major route via which liver tumors disseminate.

Methods

This was a case-control study conducted at University Medical Center Utrecht. The study compared lymph vessels in livers that had undergone RL (cases) with those in livers that had not undergone RL (controls). Histological samples were acquired from patients diagnosed with hepatocellular carcinoma (HCC) or colorectal liver metastases (CRLM) between 2017 and 2022. Lymph vessel morphology was analyzed by two researchers using podoplanin, a protein that is expressed in lymphatic endothelium. In vivo liver lymph drainage of radioembolized livers was assessed using intraoperative liver lymphangiography (ILL): during liver surgery, patent blue dye was injected into the liver parenchyma, followed by inspection for staining of perihepatic lymph structures. ILL results were compared to a previously published cohort.

Results

Immunohistochemical analysis on post-RL tumor tissues from ten patients with CRLM and nine patients with HCC revealed aberrant morphology of irradiated liver lymphatics when compared to controls (n = 3 per group). Irradiated lymphatics were tortuous (p <0.05), thickened (p <0.05) and discontinuous (p <0.05). Moreover, post-RL lymphatics had larger lumens (1.5-1.7x, p <0.0001), indicating lymph stasis. ILL revealed diminished lymphatic drainage to perihepatic lymph nodes and vessels in irradiated livers when compared to non-radioembolized controls (p = 1.0x10-4).

Conclusions

Radioembolization impairs peritumoral lymph vessel function. Further research is needed to evaluate if radioembolization impairs tumor dissemination via this route.

Impact and implications

Unilobar radioembolization can serve as an alternative to portal venous embolization for patients who are considered unresectable due to an insufficient future liver remnant. This research suggests that radioembolization impairs the function of peritumoral liver lymph vessels, potentially hindering dissemination via this route. These findings provide support for considering unilobar radioembolization over standard portal venous embolization.

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.

Efficacy of vaginal natural orifice transluminal endoscopic sentinel lymph node biopsy for endometrial cancer: a prospective multicenter cohort study

INTRODUCTION

Natural orifice transluminal endoscopic surgery (NOTES) is performed increasingly often despite the lack of high-quality evidence confirming its safety, especially for malignant diseases. The aim of this prospective study is to verify that vaginal NOTES (vNOTES) can be performed safely and effectively in early endometrial cancer staging surgery.

MATERIALS AND METHODS

This prospective study was conducted in two tertiary hospitals in southern China from January 2021 to May 2022. A total of 120 patients with stage I endometrial cancer were included. vNOTES or multiport laparoscopic staging surgery was selected according to each patient's wishes. The primary outcome was the sentinel lymph node detection rate, analyzed by a noninferiority test. The secondary outcomes were perioperative outcomes.

RESULTS

Among the 120 patients enrolled, 57 underwent vNOTES, and 63 underwent multiport laparoscopy. The patient-specific detection rates of sentinel lymph nodes were 94.73 and 96.82% in the vNOTES and laparoscopy groups, respectively. Additionally, the bilateral detection rates were 82.46 and 84.13%, and the side-specific detection rates were 88.60 and 90.48% in these two groups, respectively. All three detection rates in the vNOTES group were noninferior to those of laparoscopy group at a noninferiority cutoff of -15%. The median operation times of the vNOTES and laparoscopy groups were 132.35 and 138.73 min ( P =0.362), and the median estimated blood loss were 75 and 50 ml ( P =0.096), respectively. No intraoperative complications occurred in either group. The pain scores on the Numerical Rating Scale at both 12 h and 24 h after operation were significantly lower in the vNOTES group ( P <0.001) and the median postoperative hospital stay was significantly shorter in the vNOTES group ( P =0.001).

CONCLUSION

This study illustrates the potential applicability of vNOTES in gynecological malignancy surgery by demonstrating its safety and effectiveness in endometrial cancer staging. However, its long-term survival outcomes require further exploration.

Lymphatic flow velocity is a predictor of functional lymphatic vessels for lymphaticovenous anastomosis

BACKGROUND

Indocyanine green (ICG) lymphography is widely used to localize functional lymphatic vessels for lymphaticovenous anastomosis (LVA); however, flow velocity is rarely assessed. We aimed to evaluate the correlation between lymphatic flow velocity and the presence of functional lymphatic vessels.

METHODS

Data of a total of 924 lymphatic vessels from 273 lymphedema patients who underwent LVA between July 2018 and December 2020 were retrospectively reviewed. Lymph flow velocity was defined by considering the most proximal anatomic location enhanced by ICG at 30 min after injection and categorized into four groups; grade 1 (foot or hand), grade 2 (below knee or elbow), grade 3 (at/above knee or eblow), or grade 4 (axilla or groin). The presence of functional lymphatic vessels, which showed lymphatic fluid flow when the vessels were cut for anastomosis, was compared between the four groups.

RESULTS

A higher rate of functional lymphatic vessels was observed among lymphatic vessels with grade 3 or 4 flow velocity compared with those with grade 1 or 2 flow velocity (67.5% vs. 44.5%; p < 0.001). These findings were consistent with the observations for lymphatic vessels with a non-linear pattern in ICG lymphography (59.4% vs. 26.5%; p < 0.001). The rate of completion of LVA at surgical sites in extremities with grade 3 or 4 flow velocity was 88.1% compared with 65.8% in extremities with grade 1 or 2 velocity (p < 0.001).

CONCLUSIONS

Lymph flow velocity grading can be a simple and easy adjunctive method to determine indication for LVA in extremities with lymphedema.

A Case Report of Presumptive Primary Lymphedema Localized to the Face of a Dog

Primary lymphedema (PLE) is an uncommon diagnosis in veterinary medicine, with most of the previously described cases showing lower limb edema associated with a guarded long-term prognosis. To the authors' knowledge, this case report describes the first case of lymphedema localized unilaterally to the facial region of one-year-old German Shorthair Pointer, in which indirect CT-lymphography, combined with histopathologic examination of the skin, resulted in a tentative diagnosis of PLE.

Co-Expression of Podoplanin and CD44 in Proliferative Vitreoretinopathy Epiretinal Membranes

Epiretinal membranes (ERMs) are sheets of tissue that pathologically develop in the vitreoretinal interface leading to progressive vision loss. They are formed by different cell types and by an exuberant deposition of extracellular matrix proteins. Recently, we reviewed ERMs' extracellular matrix components to better understand molecular dysfunctions that trigger and fuel the onset and development of this disease. The bioinformatics approach we applied delineated a comprehensive overview on this fibrocellular tissue and on critical proteins that could really impact ERM physiopathology. Our interactomic analysis proposed the hyaluronic-acid-receptor cluster of differentiation 44 (CD44) as a central regulator of ERM aberrant dynamics and progression. Interestingly, the interaction between CD44 and podoplanin (PDPN) was shown to promote directional migration in epithelial cells. PDPN is a glycoprotein overexpressed in various cancers and a growing body of evidence indicates its relevant function in several fibrotic and inflammatory pathologies. The binding of PDPN to partner proteins and/or its ligand results in the modulation of signaling pathways regulating proliferation, contractility, migration, epithelial-mesenchymal transition, and extracellular matrix remodeling, all processes that are vital in ERM formation. In this context, the understanding of the PDPN role can help to modulate signaling during fibrosis, hence opening a new line of therapy.

The effects of postoperative treadmill exercise on rats with secondary lymphedema

Cancer-related lymphedema (LE) is often caused by radiotherapy and surgery such as lymph node dissection (LND). Previous studies have reported that exercise is beneficial to relieve LE, but the changes in the lymphatic system following exercise are still unclear. This study aimed to examine the changes in lymphatic drainage pathways over the exercise period and beneficial effects of exercise in rats with LE. Twelve rats were randomly allocated into exercise and control groups (EG and CG; n = 6 each). To obtain LE, inguinal and popliteal LND followed by 20 Gy irradiation was performed. Treadmill exercise was 30 minutes/day, 5 days/week over the four-week period. Consecutive indocyanine green (ICG) lymphography images were collected and classified into five patterns: i) linear; ii) splash; iii) stardust; iv) diffuse, and v) none. Ankle thickness was measured weekly. Histopathological evaluation was performed to examine the skin thickness, collagen area fraction (%) and lymphatic vessel density in harvested tissue. ICG lymphography exhibited more linear and splash patterns in the EG at week 3. The difference of swelling between both groups was significantly different at week 4 (p = 0.016). Histopathologic data revealed a thinner epidermis (p = 0.041) and dermis (p = 0.002), lower collagen area fraction (%, p = 0.002), and higher lymph vessel density (p = 0.002) in the EG than the CG. In conclusion, we found that postoperative exercise can facilitate improvement in lymphatic fluid retention in the lymphedema rat model, resulting in improvement of pathological conditions in the lymphatic system.

Loco-regional treatment with temozolomide-loaded thermogels prevents glioblastoma recurrences in orthotopic human xenograft models

Glioblastoma multiforme (GBM) is the most aggressive primary tumor of the central nervous system and the diagnosis is often dismal. GBM pharmacological treatment is strongly limited by its intracranial location beyond the blood-brain barrier (BBB). While Temozolomide (TMZ) exhibits the best clinical performance, still less than 20% crosses the BBB, therefore requiring administration of very high doses with resulting unnecessary systemic side effects. Here, we aimed at designing new negative temperature-responsive gel formulations able to locally release TMZ beyond the BBB. The biocompatibility of a chitosan-β-glycerophosphate-based thermogel (THG)-containing mesoporous SiO₂ nanoparticles (THG@SiO₂) or polycaprolactone microparticles (THG@PCL) was ascertained in vitro and in vivo by cell counting and histological examination. Next, we loaded TMZ into such matrices (THG@SiO₂-TMZ and THG@PCL-TMZ) and tested their therapeutic potential both in vitro and in vivo, in a glioblastoma resection and recurrence mouse model based on orthotopic growth of human cancer cells. The two newly designed anticancer formulations, consisting in TMZ-silica (SiO₂@TMZ) dispersed in the thermogel matrix (THG@SiO₂-TMZ) and TMZ, spray-dried on PLC and incorporated into the thermogel (THG@PCL-TMZ), induced cell death in vitro. When applied intracranially to a resected U87-MG-Red-FLuc human GBM model, THG@SiO₂-TMZ and THG@PCL-TMZ caused a significant reduction in the growth of tumor recurrences, when compared to untreated controls. THG@SiO₂-TMZ and THG@PCL-TMZ are therefore new promising gel-based local therapy candidates for the treatment of GBM.

Lymphoedema conditions disrupt endothelial barrier function in vitro

Lymphatic vessel contractions generate net antegrade pulsatile lymph flow. By contrast, impaired lymphatic vessels are often associated with lymphoedema and altered lymph flow. The effect of lymphoedema on the lymph flow field and endothelium is not completely known. Here, we characterized the lymphatic flow field of a platelet-specific receptor C-type lectin-like receptor 2 (CLEC2) deficient lymphoedema mouse model. In regions of lymphoedema, collecting vessels were significantly distended, vessel contractility was greatly diminished and pulsatile lymph flow was replaced by quasi-steady flow. In vitro exposure of human dermal lymphatic endothelial cells (LECs) to lymphoedema-like quasi-steady flow conditions increased intercellular gap formation and permeability in comparison to normal pulsatile lymph flow. In the absence of flow, LECs exposed to steady pressure (SP) increased intercellular gap formation in contrast with pulsatile pressure (PP). The absence of pulsatility in steady fluid flow and SP conditions without flow-induced upregulation of myosin light chain (MLCs) regulatory subunits 9 and 12B mRNA expression and phosphorylation of MLCs, in contrast with pulsatile flow and PP without flow. These studies reveal that the loss of pulsatility, which can occur with lymphoedema, causes LEC contraction and an increase in intercellular gap formation mediated by MLC phosphorylation.

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.

Impaired Lymphatic Drainage and Interstitial Inflammatory Stasis in Chronic Musculoskeletal and Idiopathic Pain Syndromes: Exploring a Novel Mechanism

A normal functioning lymphatic pump mechanism and unimpaired venous drainage are required for the body to remove inflammatory mediators from the extracellular compartment. Impaired vascular perfusion and/or lymphatic drainage may result in the accumulation of inflammatory substances in the interstitium, creating continuous nociceptor activation and related pathophysiological states including central sensitization and neuroinflammation. We hypothesize that following trauma and/or immune responses, inflammatory mediators may become entrapped in the recently discovered interstitial, pre-lymphatic pathways and/or initial lymphatic vessels. The ensuing interstitial inflammatory stasis is a pathophysiological state, created by specific pro-inflammatory cytokine secretion including tumor necrosis factor alpha, interleukin 6, and interleukin 1b. These cytokines can disable the local lymphatic pump mechanism, impair vascular perfusion via sympathetic activation and, following transforming growth factor beta 1 expression, may lead to additional stasis through direct fascial compression of pre-lymphatic pathways. These mechanisms, when combined with other known pathophysiological processes, enable us to describe a persistent feed-forward loop capable of creating and maintaining chronic pain syndromes. The potential for concomitant visceral and/or vascular dysfunction, initiated and maintained by the same feed-forward inflammatory mechanism, is also described.

Photoacoustic lymphangiography before and after lymphaticovenular anastomosis

Background

Lymphaticovenular anastomosis (LVA) is a minimally invasive surgical procedure used to treat lymphedema. Volumetric measurements and quality-of-life assessments are often performed to assess the effectiveness of LVA, but there is no method that provides information regarding postoperative morphological changes in lymphatic vessels and veins after LVA. Photoacoustic lymphangiography (PAL) is an optical imaging technique that visualizes the distribution of light-absorbing molecules, such as hemoglobin or indocyanine green (ICG), and provides three-dimensional images of superficial lymphatic vessels and the venous system simultaneously. In this study, we performed PAL in lymphedema patients before and after LVA and compared the images to evaluate the effect of LVA.

Methods

PAL was performed using the PAI-05 system in three patients (one man, two women) with lymphedema, including one primary case and two secondary cases, before LVA. ICG fluorescence lymphography was performed in all cases before PAL. Follow-up PAL was performed between 5 days and 5 months after LVA.

Results

PAL enabled the simultaneous visualization of clear lymphatic vessels that could not be accurately seen with ICG fluorescence lymphography and veins. We were also able to observe and analyze morphological changes such as the width and the number of lymphatic vessels and veins during the follow-up PAL after LVA.

Conclusions

By comparing preoperative and postoperative PAL images, it was possible to analyze the morphological changes in lymphatic vessels and veins that occurred after LVA. Our study suggests that PAL would be useful when assessing the effect of LVA surgery.