Characterization of Atherosclerotic Mice Reveals a Sex-Dependent Susceptibility to Plaque Calcification but No Major Changes in the Lymphatics in the Arterial Wall.

Lymphatics participate in reverse cholesterol transport, and their presence in the arterial wall of the great vessels and prior experimental results suggest their possible role in the development of atherosclerosis. The aim of this study was to characterize the lymphatic vasculature of the arterial wall in atherosclerosis. Tissue sections and tissue-cleared aortas of wild-type mice unveiled significant differences in the density of the arterial lymphatic network throughout the arterial tree. Male and female Ldlr-/- and ApoE-/- mice on a Western diet showed sex-dependent differences in plaque formation and calcification. Female mice on a Western diet developed more calcification of atherosclerotic plaques than males. The lymphatic vessels within the aortic wall of these mice showed no major changes regarding the number of lymphatic junctions and end points or the lymphatic area. However, female mice on a Western diet showed moderate dilation of lymphatic vessels in the abdominal aorta and exhibited indications of increased peripheral lymphatic function, findings that require further studies to understand the role of lymphatics in the arterial wall during the development of atherosclerosis.

The Lymphatic Vascular System: Does Nonuniform Lymphangion Length Limit Flow-Rate?

A previously developed model of a lymphatic vessel as a chain of lymphangions was investigated to determine whether lymphangions of unequal length reduce pumping relative to a similar chain of equal-length ones. The model incorporates passive elastic and active contractile properties taken from ex vivo measurements, and intravascular lymphatic valves as transvalvular pressure-dependent resistances to flow with hysteresis and transmural pressure-dependent bias to the open state as observed experimentally. Coordination of lymphangion contractions is managed by marrying an autonomous transmural pressure-dependent pacemaker for each lymphangion with bidirectional transmission of activation signals between lymphangions, qualitatively matching empirical observations. With eight lymphangions as used here and many nonlinear constraints, the model is capable of complex outcomes. The expected flow-rate advantage conferred by longer lymphangions everywhere was confirmed. However, the anticipated advantage of uniform lymphangions over those of unequal length, compared in chains of equal overall length, was not found. A wide variety of dynamical outcomes was observed, with the most powerful determinant being the adverse pressure difference, rather than the arrangement of long and short lymphangions. This work suggests that the wide variation in lymphangion length which is commonly observed in collecting lymphatic vessels does not confer disadvantage in pumping lymph.

Alternative Lymphatic Drainage Pathways in the Trunk Following Oncologic Therapy.

BACKGROUND: Anatomic and functional descriptions of trunk and breast lymphedema following breast cancer treatment are emerging as indicators of lymphatic dysfunction. Indocyanine green-lymphangiography has been instrumental in characterizing this dysfunction in the extremity and can be applied to other regions. Previous work has established a validated Pittsburgh Trunk Lymphedema Staging System to characterize such affected areas. This study aims to identify risk and protective factors for the development of truncal and upper extremity lymphedema using alternative lymphatic drainage, providing implications for medical and surgical treatment. METHODS: Patients undergoing revisional breast surgery with suspicion of upper extremity lymphedema between 12/2014 and 3/2020 were offered lymphangiography. The breast and lateral/anterior trunks were visualized and blindly evaluated for axillary and inguinal lymphatic flow. A linear-weighted Cohen's kappa statistic was calculated comparing alternative drainage evaluation. Binomial regression was used to compute relative risks (RRs). Significance was assessed at alpha = 0.05. RESULTS: Eighty-six sides (46 patients) were included. Twelve sides underwent no treatment and were considered controls. Eighty-eight percent of the noncontrols had alternative lymphatic flow to the ipsilateral axillae (64%), ipsilateral groins (57%), contralateral axillae (20.3%), and contralateral groins (9.3%). Cohen's kappa for alternative drainage was 0.631 ± 0.043. Ipsilateral axillary and contralateral inguinal drainage were associated with reduced risk of developing truncal lymphedema [RR 0.78, confidence interval (CI) 0.63-0.97, P = 0.04; RR 0.32, CI 0.13-0.79, P = 0.01, respectively]. Radiation therapy increased risk of truncal and upper extremity lymphedema (RR 3.69, CI 0.96-14.15, P = 0.02; RR 1.92, CI 1.09-3.39, P = 0.03, respectively). Contralateral axillary drainage and axillary lymph node dissection were associated with increased risk of upper extremity lymphedema (RR 4.25, CI 1.09-16.61, P = 0.01; RR 2.83, CI 1.23-6.52, P = 0.01, respectively). CONCLUSIONS: Building upon previous work, this study shows risk and protective factors for the development of truncal and upper extremity lymphedema. Most prevalent alternative channels drain to the ipsilateral axilla and groin. Ipsilateral axillary and contralateral inguinal drainage were associated with reduced risk of truncal lymphedema. Patients with radiation, axillary dissection, and contralateral axillary drainage were associated with increased risk of upper extremity lymphedema. These findings have important clinical implications for postoperative manual lymphatic drainage and for determining eligibility for lymphovenous bypass surgery.

Real-Time Evaluation of Absolute, Cytosolic, Free Ca2+ and Corresponding Contractility in Isolated, Pressurized Lymph Vessels.

The lymphatic vasculature, now often referred to as "the third circulation," is located in many vital organ systems. A principal mechanical function of the lymphatic vasculature is to return fluid from extracellular spaces back to the central venous ducts. Lymph transport is mediated by spontaneous rhythmic contractions of lymph vessels (LVs). LV contractions are largely regulated by the cyclic rise and fall of cytosolic, free calcium ([Ca2+]i). This paper presents a method to concurrently calculate changes in absolute concentrations of [Ca2+]i and vessel contractility/rhythmicity in real time in isolated, pressurized LVs. Using isolated rat mesenteric LVs, we studied changes in [Ca2+]i and contractility/rhythmicity in response to drug addition. Isolated LVs were loaded with the ratiometric Ca2+-sensing indicator Fura-2AM, and video microscopy coupled with edge-detection software was used to capture [Ca2+]i and diameter measurements continuously in real time. The Fura-2AM signal from each LV was calibrated to the minimum and maximum signal for each vessel and used to calculate absolute [Ca2+]i. Diameter measurements were used to calculate contractile parameters (amplitude, end diastolic diameter, end systolic diameter, calculated flow) and rhythmicity (frequency, contraction time, relaxation time) and correlated with absolute [Ca2+]i measurements.

Advances in lymphatic metastasis of non-small cell lung cancer.

Lung cancer is a deeply malignant tumor with high incidence and mortality. Despite the rapid development of diagnosis and treatment technology, abundant patients with lung cancer are still inevitably faced with recurrence and metastasis, contributing to death. Lymphatic metastasis is the first step of distant metastasis and an important prognostic indicator of non-small cell lung cancer. Tumor-induced lymphangiogenesis is involved in the construction of the tumor microenvironment, except promoting malignant proliferation and metastasis of tumor cells, it also plays a crucial role in individual response to treatment, especially immunotherapy. Thus, this article reviews the current research status of lymphatic metastasis in non-small cell lung cancer, in order to provide some insights for the basic research and clinical and translational application in this field.

Impaired meningeal lymphatic drainage in Listeria monocytogenes infection.

Previous studies have demonstrated an association between lymphatic vessels and diseases caused by bacterial infections. Listeria monocytogenes (LM) bacterial infection can affect multiple organs, including the intestine, brain, liver and spleen, which can be fatal. However, the impacts of LM infection on morphological and functional changes of lymphatic vessels remain unexplored. In this study, we found that LM infection not only induces meningeal and mesenteric lymphangiogenesis in mice, but also impairs meningeal lymphatic vessels (MLVs)-mediated macromolecules drainage. Interestingly, we found that the genes associated with lymphatic vessel development and function, such as Gata2 and Foxc2, were downregulated, suggesting that LM infection may affect cellular polarization and valve development. On the other hand, photodynamic ablation of MLVs exacerbated inflammation and bacterial load in the brain of mice with LM infection. Overall, our findings indicate that LM infection induces lymphangiogenesis and may affect cell polarization, cavity formation, and valve development during lymphangiogenesis, ultimately impairing MLVs drainage.

Central conducting lymphatic anomaly: from bench to bedside.

Central conducting lymphatic anomaly (CCLA) is a complex lymphatic anomaly characterized by abnormalities of the central lymphatics and may present with nonimmune fetal hydrops, chylothorax, chylous ascites, or lymphedema. CCLA has historically been difficult to diagnose and treat; however, recent advances in imaging, such as dynamic contrast magnetic resonance lymphangiography, and in genomics, such as deep sequencing and utilization of cell-free DNA, have improved diagnosis and refined both genotype and phenotype. Furthermore, in vitro and in vivo models have confirmed genetic causes of CCLA, defined the underlying pathogenesis, and facilitated personalized medicine to improve outcomes. Basic, translational, and clinical science are essential for a bedside-to-bench and back approach for CCLA.

Sensitivity of Each Index of Doppler, Cross, Uncollapsible, Parallel, and Superficial Fascia in Lymphatic Ultrasound.

Background: Recently, the usefulness of lymphatic ultrasound has been reported. It is beneficial not only to identify lymphatic vessels but also to evaluate lymphatic degeneration and diagnose lymphedema. We previously proposed D-CUPS (Doppler, Cross, Uncollapsible, Parallel, and Superficial fascia) to identify the lymphatic vessels on ultrasound. The purpose of this study was to clarify the sensitivity of each index of D-CUPS. Methods: We performed a retrospective study of 27 patients (44 limbs, 98 sites) with lower extremity lymphedema, who underwent lymphaticovenous anastomosis (LVA). We performed a lymphatic ultrasound the day before surgery. We used a linear probe commonly used for venous ultrasound (Noblus EUP-L65; Hitachi Medical Corp., Tokyo, Japan). We applied the D-CUPS index to identify the lymphatic vessels on ultrasound. We checked whether lymphatic vessels consistent with preoperative lymphatic ultrasound findings were observed during the LVA. We also calculated the sensitivity of each D-CUPS index. Results: All the 27 patients were women, with a mean age of 59.7 years. Totally, 98 incisions were made (59 incisions on the thigh and 39 incisions on the lower leg). During LVA, lymphatic vessels consistent with the preoperative lymphatic ultrasound findings were observed at all the sites. The sensitivities of each indicator of D-CUPS were 100.0%, 100.0%, 68.4%, 19.4%, and 100.0%, respectively. Conclusion: The sensitivity was 100.0% in D, C, and S. Although each index separately was not perfect, by combining them appropriately, we were able to identify lymphatic vessels with certainty.

The N-LVA Study: effectiveness and cost-effectiveness of lymphaticovenous anastomosis (LVA) for patients with cancer who suffer from chronic peripheral lymphoedema - study protocol of a multicentre, randomised sham-controlled trial.

INTRODUCTION: Cancer-related lymphoedema is one of the most debilitating side-effects of cancer treatment with an overall incidence of 15.5%. Patients may suffer from a variety of symptoms, possibly resulting in a diminished health-related quality of life (HRQoL). A microsurgical technique known as lymphaticovenous anastomosis (LVA) might be a promising treatment option. The objective of this study is to evaluate whether LVA is effective and cost-effective compared with sham surgery in improving the HRQoL. METHODS AND ANALYSIS: A multicentre, double-blind, randomised sham-controlled trial conducted in three university hospitals in the Netherlands. The study population comprises 110 patients over the age of 18 years with unilateral, peripheral cancer-related lymphoedema, including 70 patients with upper limb lymphoedema and 40 patients with lower limb lymphoedema. A total of 55 patients will undergo the LVA operation, while the remaining 55 will undergo sham surgery. The follow-up will be at least 24 months. Patients are encouraged to complete the follow-up by explaining the importance of the study. Furthermore, patients may benefit from regular monitoring moments for their lymphoedema. The primary outcome is the HRQoL. The secondary outcomes are the limb circumference, excess limb volume, changes in conservative therapy, postoperative complications, patency of the LVA and incremental cost-effectiveness. ETHICS AND DISSEMINATION: The study was approved by the Medical Ethical Committee of Maastricht University Medical Center on 20 September 2023 (NL84169.068.23). The results will be presented at scientific conferences and published in peer-reviewed medical journals. TRIAL REGISTRATION NUMBER: NCT06082349.

100 anastomoses: a two-year single-center experience with robotic-assisted micro- and supermicrosurgery for lymphatic reconstruction.

Robotic-assisted microsurgery has gained significant attention in recent years following the introduction of two dedicated microsurgical robotic systems specifically designed for this purpose. These feature higher degrees of movement and motion scaling which are useful tools, especially when performing surgery in areas of the body which are difficult to access. Robotic-assisted microsurgery has been implemented in lymphatic surgery as well as soft tissue reconstructive surgery at our institution over the past 2.5 years. Our study gives an insight into the details and outcomes of the first 100 consecutive (super-) microsurgical anastomoses in peripheral and central lymphatic reconstruction performed with the Symani® Surgical System between 2021 and 2024. In total, 67 patients were treated, receiving robotic-assisted lymphatic reconstruction with lymphatic tissue transfer (LTT) and/or lymphovenous anastomoses (LVA)/lympholymphatic anastomoses (LLA). No anastomosis-associated complications were recorded postoperatively. The majority of patients reported a postoperative improvement of their lymphedema or central lymphatic disorder. In conclusion, we show the successful implementation of the Symani® Surgical System into our clinical practice of lymphatic reconstruction. Although the necessary intraoperative setup and the use of intrinsic motion scaling lead to a slight increase in operating time, the presented study demonstrates the advantages of robotic assistance which becomes particularly evident in lymphatic surgery due to the involved deep surgical sites and the need for supermicrosurgical techniques.

A Long-Acting Lyotropic Liquid Crystalline Implant Promotes the Drainage of Macromolecules by Brain-Related Lymphatic System in Treating Aged Alzheimer's Disease.

Numerous evidence has demonstrated that the brain is not an immune-privileged organ but possesses a whole set of lymphatic transport system, which facilitates the drainage of harmful waste from brains to maintain cerebral homeostasis. However, as individuals age, the shrinkage and dysfunction of meningeal and deep cervical lymphatic networks lead to reduced waste outflow and elevated neurotoxic molecules deposition, further inducing aging-associated cognitive decline, which act as one of the pathological mechanisms of Alzheimer's disease. Consequently, recovering the function of meningeal and deep cervical lymph node (dCLNs) networks (as an important part of the brain waste removal system (BWRS)) of aged brains might be a feasible strategy. Herein we showed that the drug brain-entering efficiency was highly related to administration routes (oral, subcutaneous, or dCLN delivery). Besides, by injecting a long-acting lyotropic liquid crystalline implant encapsulating cilostazol (an FDA-approved selective PDE-3 inhibitor) and donepezil hydrochloride (a commonly used symptomatic relief agent to inhibit acetylcholinesterase for Alzheimer's disease) near the deep cervical lymph nodes of aged mice (about 20 months), an increase of lymphatic vessel coverage in the nodes and meninges was observed, along with accelerated drainage of macromolecules from brains. Compared with daily oral delivery of cilostazol and donepezil hydrochloride, a single administered dual drugs-loaded long-acting implants releasing for more than one month not only elevated drug concentrations in brains, improved the clearing efficiency of brain macromolecules, reduced Aß accumulation, enhanced cognitive functions of the aged mice, but improved patient compliance as well, which provided a clinically accessible therapeutic strategy toward aged Alzheimer's diseases.

Banxia Xiexin decoction promotes gastric lymphatic pumping by regulating lymphatic smooth muscle cell contraction and energy metabolism in a stress-induced gastric ulceration rat model.

ETHNOPHARMACOLOGICAL RELEVANCE: The traditional Chinese medicine (TCM) formula Banxia Xiexin decoction (BXD) has definite therapeutic effect in treating stress-induced gastric ulceration (SIGU) and many other gastrointestinal diseases, but its effect on gastric lymphatic pumping (GLP) remains unclear. AIM OF THE STUDY: Elucidating the role of GLP in SIGU and BXD treatment, and exploring the molecular mechanisms of GLP regulation. MATERIALS AND METHODS: In vivo GLP imaging were performed on SIGU rat model, and the lymphatic dynamic parameters were evaluated. Gastric antrum tissues and serum were collected for macroscopic, histopathological and ulcerative parameters analysis. Gastric lymphatic vessel (GLV) tissues were collected for RNA-Seq assays. Differentially expressed genes (DEGs) were screened from RNA-Seq result and submitted for transcriptomic analysis. Key DEGs and their derivative proteins were measured by qRT-PCR and WB. RESULTS: GLP was significantly suppressed in SIGU rats. BXD could recover GLP, ameliorate stomach lymphostasis, and alleviate the ulcerative damage. Transcriptome analysis of GLV showed the top up-DEGs were concentrated in smooth muscle contraction signaling pathway, while the top the down-DEGs were concentrated in energy metabolism pathways especially fatty acid degradation pathway, which indicated BXD can promote lymphatic smooth muscle contraction, regulate energy metabolism, and reduce fatty acid degradation. The most possible target of these mechanisms was the lymphatic smooth muscle cells (LSMCs) which drove the GLP. This speculation was further validated by the qRT-PCR and WB assessments for the level of key genes and proteins. CONCLUSIONS: By activating the smooth muscle contraction signaling pathway, restoring energy supply, modulating energy metabolism program and reducing fatty acid degradation, BXD effectively recovered GLP, mitigated the accumulation of inflammatory cytokines and metabolic wastes in the stomach, which importantly contributes to its efficacy in treating SIGU.

Unraveling a hidden player in lymphovascular invasion in bladder cancer.

Tumor invasion into the lymphatic vasculature represents a critical step during malignant progression of epithelial cancers. In this issue of Cancer Cell, Zheng et al. unravel how cancer-associated fibroblasts interact with lymphatic endothelial cells and the extracellular matrix to promote lymphatic tumor invasion and suggest that these processes could be treatment targets.

CD4+ CD11b+ T cells infiltrate and aggravate the traumatic brain injury depending on brain-to-cervical lymph node signaling.

AIM: We aim to identify the specific CD4+ T-cell subtype influenced by brain-to-CLN signaling and explore their role during the acute phase of traumatic brain injury (TBI). METHOD: Cervical lymphadenectomy or cervical afferent lymphatic ligation was performed before TBI. Cytokine array and western blot were used to detect cytokines, while the motor function was assessed using mNss and rotarod test. CD4+ T-cell subtypes in blood, brain, and CLNs were analyzed with Cytometry by time-of-flight analysis (CyTOF) or fluorescence-activated cell sorting (FACS). Brain edema and volume changes were measured by 9.4T MRI. Neuronal apoptosis was evaluated by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining. RESULTS: Cervical lymphadenectomy and ligation of cervical lymphatic vessels resulted in a decreased infiltration of CD4+ T cells, specifically CD11b-positive CD4+ T cells, within the affected region. The population of CD4+ CD11b+ T cells increased in ligated CLNs, accompanied by a decrease in the average fluorescence intensity of sphingosine-1-phosphate receptor-1 (S1PR1) on these cells. Administration of CD4+ CD11b+ T cells sorted from CLNs into the lateral ventricle reversed the attenuated neurologic deficits, brain edema, and lesion volume following cervical lymphadenectomy. CONCLUSION: The infiltration of CD4+ CD11b+ T cells exacerbates secondary brain damage in TBI, and this process is modulated by brain-to-CLN signaling.

Glymphatic-lymphatic coupling: assessment of the evidence from magnetic resonance imaging of humans.

The discoveries that cerebrospinal fluid participates in metabolic perivascular exchange with the brain and further drains solutes to meningeal lymphatic vessels have sparked a tremendous interest in translating these seminal findings from animals to humans. A potential two-way coupling between the brain extra-vascular compartment and the peripheral immune system has implications that exceed those concerning neurodegenerative diseases, but also imply that the central nervous system has pushed its immunological borders toward the periphery, where cross-talk mediated by cerebrospinal fluid may play a role in a range of neoplastic and immunological diseases. Due to its non-invasive approach, magnetic resonance imaging has typically been the preferred methodology in attempts to image the glymphatic system and meningeal lymphatics in humans. Even if flourishing, the research field is still in its cradle, and interpretations of imaging findings that topographically associate with reports from animals have yet seemed to downplay the presence of previously described anatomical constituents, particularly in the dura. In this brief review, we illuminate these challenges and assess the evidence for a glymphatic-lymphatic coupling. Finally, we provide a new perspective on how human brain and meningeal clearance function may possibly be measured in future.

CD112 Supports Lymphatic Migration of Human Dermal Dendritic Cells.

Dendritic cell (DC) migration from peripheral tissues via afferent lymphatic vessels to draining lymph nodes (dLNs) is important for the organism's immune regulation and immune protection. Several lymphatic endothelial cell (LEC)-expressed adhesion molecules have thus far been found to support transmigration and movement within the lymphatic vasculature. In this study, we investigated the contribution of CD112, an adhesion molecule that we recently found to be highly expressed in murine LECs, to this process. Performing in vitro assays in the murine system, we found that transmigration of bone marrow-derived dendritic cells (BM-DCs) across or adhesion to murine LEC monolayers was reduced when CD112 was absent on LECs, DCs, or both cell types, suggesting the involvement of homophilic CD112-CD112 interactions. While CD112 was highly expressed in murine dermal LECs, CD112 levels were low in endogenous murine dermal DCs and BM-DCs. This might explain why we observed no defect in the in vivo lymphatic migration of adoptively transferred BM-DCs or endogenous DCs from the skin to dLNs. Compared to murine DCs, human monocyte-derived DCs expressed higher CD112 levels, and their migration across human CD112-expressing LECs was significantly reduced upon CD112 blockade. CD112 expression was also readily detected in endogenous human dermal DCs and LECs by flow cytometry and immunofluorescence. Upon incubating human skin punch biopsies in the presence of CD112-blocking antibodies, DC emigration from the tissue into the culture medium was significantly reduced, indicating impaired lymphatic migration. Overall, our data reveal a contribution of CD112 to human DC migration.

Fibroblasts facilitate lymphatic vessel formation in transplanted heart.

Rationale: Lymphangiogenesis plays a critical role in the transplanted heart. The remodeling of lymphatics in the transplanted heart and the source of newly formed lymphatic vessels are still controversial, especially the mechanism of lymphangiogenesis remains limited. Methods: Heart transplantation was performed among BALB/c, C57BL/6J, Cag-Cre, Lyve1-CreERT2;Rosa26-tdTomato and Postn(2A-CreERT2-wpre-pA)1;Rosa26-DTA mice. scRNA-seq, Elisa assay, Western blotting, Q-PCR and immunohistochemical staining were used to identify the cells and cell-cell communications of allograft heart. Cell depletion was applied to in vivo and in vitro experiments. Whole-mount staining and three-dimensional reconstruction depicted the cell distribution within transparent transplanted heart. Results: Genetic lineage tracing mice and scRNA-seq analysis have revealed that these newly formed lymphatic vessels mainly originate from recipient LYVE1+ cells. It was found that LECs primarily interact with activated fibroblasts. Inhibition of lymphatic vessel formation using a VEGFR3 inhibitor resulted in a decreased survival time of transplanted hearts. Furthermore, when activated fibroblasts were ablated in transplanted hearts, there was a significant suppression of lymphatic vessel generation, leading to earlier graft failure. Additional investigations have shown that activated fibroblasts promote tube formation of LECs primarily through the activation of various signaling pathways, including VEGFD/VEGFR3, MDK/NCL, and SEMA3C/NRP2. Interestingly, knockdown of VEGFD and MDK in activated fibroblasts impaired cardiac lymphangiogenesis after heart transplantation. Conclusions: Our study indicates that cardiac lymphangiogenesis primarily originates from recipient cells, and activated fibroblasts play a crucial role in facilitating the generation of lymphatic vessels after heart transplantation. These findings provide valuable insights into potential therapeutic targets for enhancing graft survival.

Deep learning-based label-free imaging of lymphatics and aqueous veins in the eye using optical coherence tomography.

We demonstrate an adaptation of deep learning for label-free imaging of the micro-scale lymphatic vessels and aqueous veins in the eye using optical coherence tomography (OCT). The proposed deep learning-based OCT lymphangiography (DL-OCTL) method was trained, validated and tested, using OCT scans (23 volumetric scans comprising 19,736 B-scans) from 11 fresh ex vivo porcine eyes with the corresponding vessel labels generated by a conventional OCT lymphangiography (OCTL) method based on thresholding with attenuation compensation. Compared to conventional OCTL, the DL-OCTL method demonstrates comparable results for imaging lymphatics and aqueous veins in the eye, with an Intersection over Union value of 0.79 ± 0.071 (mean ± standard deviation). In addition, DL-OCTL mitigates the imaging artifacts in conventional OCTL where the OCT signal modelling was corrupted by the tissue heterogeneity, provides ~ 10 times faster processing based on a rough comparison and does not require OCT-related knowledge for correct implementation as in conventional OCTL. With these favorable features, DL-OCTL promises to improve the practicality of OCTL for label-free imaging of lymphatics and aqueous veins for preclinical and clinical imaging applications.