Primo Vessel as a Novel Cancer Cell Migration Path from Testis with Nanoparticle-Labeled and GFP Expressing Cancer Cells

Background/aimRecently, a novel circulatory system, the primo vascular system (PVS), was found to be a potent metastatic route of cancer cells. The aim of the current work is to demonstrate that cancer cells injected into the testis migrate through the primo vessel (PV).Materials and methodsNCI-H460 cells labeled with fluorescent nanoparticles (FNP) or green fluorescent protein (GFP) gene transfection were injected into testicular parenchyma in 24 rats. After 24 hours of injection, the abdominal cavity was investigated via a stereomicroscope, to detect the PVS, and the samples were analyzed histologically with 4′,6-diamidino-2-phenylindole (DAPI) and hematoxylin and eosin.ResultsInjected cancer cells were detected inside the PVS distributed on the abdominal organs. Some were detected inside intestinal parenchyma into which the attached primo vessels (PVs) entered.ConclusionThe results supported the fact that the PVS may be a novel migration path of cancer cells, in addition to the lymphatic and hematogenous routes.     

Study of the primo vascular system utilizing a melanoma tumor model in a green fluorescence protein expressing mouse

A melanoma tumor is a representative malignant tumor. Melanoma tumor growth involves vigorous angiogenesis around the tumor and a vasculogenic-like network inside an aggressive tumor. Primo vessels (PVs) are also found on the surface of the tumor and coexist alongside blood vessels (BVs), and sometimes within the BVs. We hypothesized that the primo vessels system plays a significant role in regulating the development of a melanoma tumor, and therefore has a tight coupling with BVs and angiogenesis. To prove this hypothesis, we developed a murine melanoma model by inoculating melanoma cell lines into the abdominal region. We used a green fluorescent protein (GFP) expressing mouse as a host to distinguish the endogenous source of the tumor PVs. We found strong formation of PVs on the tumor that coexisted with BVs and expression of GFP. PVs also had a tight coupling with adipose tissues, especially with white adipose tissue. These data suggest that the PVs of an induced melanoma tumor evolve endogenously from the host body and may be highly related to BVs and adipose tissue. This model of PVs in an overexpressing GFP mouse is a useful system for observing PVs, primo nodes, and primo vessel networks, and has potential to be developed as a model for examining novel treatments for cancer metastasis.     

Differential Gene Expression by RNA-Seq Analysis of the Primo Vessel in the Rabbit Lymph

For the connectome of primo vascular system, some long-type primo vessels dyed with Alcian blue injected into inguinal nodes, abdominal node, and axially nodes were visualized, which passed over around the vena cava of the rabbit. The Alcian blue dye revealed primo vessels and colored blue in the rabbit lymph vessels. The length of long-type primo vessels was 18 cm on average, of which diameters were about 20–30 μm, and the lymph vessels had diameters of 100–150 μm. Three different tissues of pure primo vessel, mixed primo + lymph vessel, and only lymph vessel were made to undergo RNA-Seq analysis by next-generation sequencing. We also analyzed differentially expressed genes (DEGs) from the RNA-Seq data, in which 30 genes of the primo vessels, primo + lymph vessels, and lymph vessels were selected for primo marker candidates. From the plot of DEG analysis, 10 genes had remarkably different expression pattern on the Group 1 (primo vessel) vs Group 3 (lymph vessel). With Fragments Per Kilobase of exon per Million the cutoff p-value for each gene was < 0.05. Fragments Per Kilobase of exon per Million of the 10 genes such as IGHM, HLA-DRA, HIST1H41, LPL, CD36, SRGN, DGAT2, SNCG, CD48, and GPD1 for primo vessels compared with those of lymph vessels increased twice or thrice. These results suggest that the selected genes could be used for the specific marker to construct primo connectome of circuit system in the rabbit.     

Visualization of the Primo Vascular System Afloat in a Lymph Duct

Because of the potential roles of the primo vascular system (PVS) in cancer metastasis, immune function, and regeneration, understanding the molecular biology of the PVS is desirable. The current state of PVS research is comparable to that of lymph research prior to the advent of Lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1). There is very little knowledge of the molecular biology of the PVS due to difficulties in identifying and isolating primo endothelial cells. Present investigations rely on the morphology and the use of differential staining procedures to identify the PVS within tissues, making detailed molecular studies all but impossible. To overcome such difficulties, one may emulate the explosive development of lymph molecular biology. For this purpose, there is a need for a reliable method to obtain PVS specimens to initiate the molecular investigation. One of the most reliable methods is to detect the primo vessels and primo nodes afloat in the lymph flow. The protocols for observation of the PVS in the large lymph ducts in the abdominal cavity and the thoracic cavity were reported earlier. These methods require a laparectomy and skillful techniques. In this work, we present a protocol to identify and harvest PVS specimens from the lymph ducts connecting the inguinal and the axillary nodes, which are located entirely in the skin. Thus, the PVS specimen is more easily obtainable. This method is a stepping-stone toward development of a system to monitor migration of cancer cells in metastasis from a breast tumor to the axillary nodes, where cancer cells use the PVS as a survival rope in hostile lymph flow.     

Fluorescent Nanoparticles for Observing Primo Vascular System Along Sciatic Nerve

The primo vascular system was found in the epineurium along the rat sciatic nerve following subcutaneous injection of fluorescent nanoparticles at the Zusanli acupoint (ST-36). Nanoparticles were injected into the primo-vessel near ST-36 and flowed along the sciatic nerve. Fluorescence revealed a structure in the epineurium that was hardly detectable. Images of the isolated sample stained with 4′,6-diamidino-2-phenylindole were captured using confocal microscopy. These images showed the distinctive nuclei distribution and multi-lumen structure of primo-vessels that differentiate them from lymphatic vessels, blood capillaries and nerves. This study demonstrates a new use for nanoparticles in fluorescence reflectance imaging techniques during in vivo imaging of primo-vessels.     

Putative Primo-Vascular System in Rabbit Placenta

The primo vascular system (PVS) is a very important topic of study nowadays because of their role in transport and regeneration of tissue and in cell migration and cancer metastasis. The PVS was detected in different organs of the rabbit but not in the placenta. In this work, we observe the PVS inside the blood vessels of the placenta for the first time. The main characteristic features of the primo vessels (PVs) from the rabbit placenta were in agreement with the PVS in different organs of animals, including the rod-shaped nuclei and their arrangement.     

Isolation and Morphological Features of Primo Vessels in Rabbit Lymph Vessels

Until now, even though intensive research has been dedicated to the primo vascular system (PVS) during these years, no statistical data on primo vessels and primo vessels in lymph flow have been available. Recently, the general morphological features of primo vessels in lymph vessels around the abdominal aorta were identified from microdissections of tissues from New Zealand White rabbits, and with Alcian blue staining, primo vessels in lymphatic vessels could be definitely identified under a digital microscope. The micro-dissected specimens in situ reveal rod-shaped nuclei stained by Acridine orange. The blue-stained nuclei, which were distributed in a broken-lined stripe, formed a tube structure of about 20 μm in diameter. The distance between the nuclei of two cells on neighboring aligned stripes, which is also the diameter of the micro tube, was measured to be about 5～10μm. The average length of the primo vessels was 2.4 mm, with the longest being 5.6 mm. The average size of the primo vessel was 50 μm, and the average diameters of the primo and the lymph vessels were 26.0 μm and 258.5 μm, respectively. Occasionally, without the use of Alcian blue staining, milk-white transparent primo vessels were observed floating in lymph vessels. Thus, we suggest that the PVS might also have an important function connected with the lymph system. We also expect the traditional Korean meridian system to leave its invisible world during the last thousands of years and soon enter the visible scientific world.     

Primo Vascular System in the Subarachnoid Space of the Spinal Cord of a Pig

The primo vascular system was recently observed in the central nervous systems of rabbits and rats, but no investigations in large animals have been reported. In the present work we found a putative primo vascular system in the spinal cord of a pig. We obtained spines from four healthy pigs and fixed them with paraformaldehyde. The primo vessels were expected to lie in the subarachnoid space between the pia mater and the arachnoid mater. The composite of three membranes (the pia, the arachnoid, and the dura maters) wrapping the spinal cord was peeled off, isolated from the spine, and put on a slide glass. This composite was stained with 4′,6′-Diamidino-2-phenylindole (DAPI) and phalloidin to show the nuclei and the f-actin, respectively, in the cells of the primo vessels. We observed eleven pieces of the putative primo vessels in the subarachnoid space of the spines at the thoracic spinal nerve area. They had the typical rod-shaped nuclei distributed in a broken line, and f-actin signals around nuclei. The lengths of the nuclei were 12–15 μm, and the thicknesses of the primo vessels were 8～20 μm, which were consistent with other primo vessels that had been observed in the various organs of rabbits, rats, and mice. In addition, we observed branching of the primo vessels, which is again an expected result from previous works. In conclusion, a primo vessel was observed in the subarachnoid space of the spinal cord of a pig. This was the first observation of a primo vessel in a large animal, and the staining method used to observe the primo vessel in a fixed sample was newly developed in this work.     

Protocol for the Observation of the Primo Vascular System in the Lymph Vessels of Rabbits

Molecular-level understanding of the structure and the functions of the lymphatic system has greatly enhanced the importance of this second circulation system, especially in connection with cancer metastasis and inflammation. Recently, a third circulatory system, the primo vascular system (PVS) was found in various parts of an animal's body, especially as threadlike structures floating in the lymphatic flow in lymph vessels. Although the medical significance of this emerging system will require much work in the future, at present, several important suggestions in connection with immune cells, stem cells, and cancer metastasis have already appeared. Experiments to observe the PVS in the lymph vessels near the caudal vena cava of rabbits and rats have been performed by several independent teams, but reproduction requires considerable skill and technical know-how. In this article, we provide a detailed protocol to detect the PVS inside the lymph vessels of a rabbit. Detection and isolation are the first steps in unraveling the physiological functions of the PVS, which awaits intensive research.     

Primo Vascular System in Human Umbilical Cord and Placenta

The primo vascular system (PVS) has been observed in various animals such as mice, rats, rabbits, dogs, swine, and cow, but not in humans. In this work, we report on the observation of a human PVS on both the epithelial fascia and inside the blood vessels of the umbilical cord (UC). The main morphological characteristics of the primo vessels (PVs) and primo nodes (PNs) from the human UC were in agreement with those of the PVS in various animal organs, including the thicknesses and the transparency of the PVs, the sizes of the PNs, the broken-line arrangement of the rod-shaped nuclei, the sparse distribution of nuclei, and the presence of hollow lumens in the central inner parts of the PNs. It was rather surprising that the human PV was not thicker than the PVs from small animals. The difference between the PVS and blood/lymph vessels was confirmed using immunofluorescence staining of von Willebrand factor, CD31, LYVE-1, and D2-40. The positive expression of the PVS to proliferating cell nuclear antigen, a cell-proliferation marker, was consistent with the recent finding of very small embryonic-like stem cells in the PVS of mice.     

Effective Isolation of Primo Vessels in Lymph Using Sound- and Ultrasonic-wave Stimulation

The effects of stimulation with sound and ultrasonic waves of a specific bandwidth on the microdissection of primo vessels in lymphatic vessels of rabbit were investigated. The primo vessels stained with alcian-blue dye injected in the lymph nodes were definitely visualized and more easily isolated by sound-wave vibration and ultrasonic stimulation applied to rabbits at various frequencies and intensities. With sound wave at 7 Hz and ultrasonic waves at 2 MHz, the probability of detecting the primo vessels was improved to 90%; however, without wave stimulation the probability of discovering primo vessels was about 50% only. Sound and ultrasonic waves at specific frequency bands should be effective for microdissection of the primo vessels in the abdominal lymph of rabbit. We suggest that oscillation of the primo vessels by sound and ultrasonic waves may be useful to visualize specific primo structure, and wave vibration can be a very supportive process for observation and isolation of the primo vessels of rabbits.     

Bonghan Ducts as Possible Pathways for Cancer Metastasis

ObjectiveThe present study has been designed to find a possible new route for the metastasis of cancer cells on the fascia surrounding tumor tissue using a novel technique of trypan blue staining.Materials and MethodsTumor tissues were grown in the skin of nude mice after sub-cutaneous inoculation with human lung cancer cells. Trypan blue was recently identified as a dye with specificity for Bonghan ducts (BHDs) and not other tissues, such as blood or lymph vessels or nerves.ResultsWe demonstrate that the trypan blue staining technique allows the first visualization of BHDs which are connected to tumor tissues.ConclusionSince BHDs are known to make up a circulatory system corresponding to acu puncture meridians or collaterals, we propose that, in addition to the currently known blood or lymph vessels, BHDs on tumor tissue fascia may be a novel pathway for metastasis.     

A New Definition of an Acupuncture Meridian

This article provides a new definition of an acupuncture meridian. It suggests that a meridian consists of a distal tract of tissue that is affected by organ function. In the 1960s, Kim discovered the primo vascular system and regarded the superficial primo vessels as equating to the meridians. Instead, this article suggests that the superficial primo vessels merely underlie the meridians, in that they enable their creation, which is why some meridians are said to occur along the paths of superficial primo vessels. But the meridians themselves do not have a dedicated anatomical structure; instead they are merely tracts of tissue whose normal function is impeded when the related abdominal organ is stressed. It is hypothesized that the organ information is communicated in electrical waves that may travel through the connective tissue sheaths of the superficial primo vessels. Hence, the primo vessels serve as an inadvertent transport for this information, but the organ information is independent of the physiological purpose of the primo vascular system, as are the resultant meridians.     

Homing of the Stem Cells from the Acupoint ST-36 to the Site of a Spinal Cord Injury: A Preliminary Study

Homing of stem cells (SCs) to desired targets such as injured tissues remains a lingering problem in cell-based therapeutics. Studies on the biodistribution of intravenously administered SCs have shown the inefficacy of blood vessels as the homing path because most of the injected SCs are captured in the capillary beds of the lungs. We considered an alternative administration method using the acupuncture meridians or the primo vascular system. We injected SCs at the acupoint Zusanli (ST-36) below the knee of a nude mouse with a spinal cord injured at the thoracic T9-10 vertebrae. The SCs migrated from the ST-36, along the sciatic nerve, the lumbar 4-5, and then the spinal cord to the injury point T9-10. The SCs were not randomly scattered but were rather well aligned like marathon race runners, along the primo vascular system route toward the injury point. We observed the SCs at 1, 3, 6, 9, 12, and 15 hours after injection. The fast runners among the injected SCs took about 6 hours to reach the sciatic nerve, about 9 hours to reach the lumbar 4-5, and about 15 hours to reach the injury point T9-10.     

莪术醇对斑马鱼的血管生成活性及作用机制研究

目的:初步研究莪术醇促进血管生成的活性及作用机制,为临床用药提供依据.方法:采用斑马鱼生物模式,观察莪术醇对斑马鱼胚胎体节间血管生长、成鱼剪尾后血管再生和仔鱼切尾后组织再生情况.采用相对荧光定量PCR法检测仔鱼切尾后体内血管内皮生长因子(VEGFA)及受体(VEGFR2)基因的表达.结果:莪术醇能使斑马鱼胚胎体节间血管侧生出新的血管,使成鱼剪尾后血管再生加快,使仔鱼切尾后尾部再生加快.且莪术醇能提高仔鱼体内VEGFA及VEGFR2基因的表达量,促进仔鱼切尾后的尾部再生.结论:莪术醇能促进斑马鱼的血管生成,提高仔鱼切尾后体内VEGFA及VEGFR2基因的表达量,促进尾部再生.     

The Primo Vascular System as a Possible Exosomal Route Across the Body: Implications for Tumor Proliferation and Metastasis

This literature study article will present the possibility of a correlation between the energy meridians of Traditional Chinese Medicine, which can be traced back to the recently described primo vessels (formerly known as Bong-Han ducts), their composition, and the ability of tumors to proliferate and metastasize. It is proposed that microvesicular bodies such as exosomes, known to be involved in cell-to-cell communication, immune response, and tumor proliferation, could be moving across the body via the primo vascular system. The ubiquity of the primo vascular system and its penetration through the blood–brain barrier could also explain the ability of some peripheral tumors (e.g., breast tumor) to metastasize in the brain.     

人参皂苷Rh2对小鼠移植瘤生长及对细胞间连接黏附分子表达的影响

目的：观察人参皂苷Rh₂对小鼠移植瘤生长及其对细胞间连接黏附分子(JAM)在癌组织表达的影响，探讨其抗肿瘤作用。方法：昆明种小鼠40只，前肢皮下接种S180小鼠癌性腹水0.2 mL，成瘤后随机分为2组，实验组给予人参皂苷Rh₂(20 mg·kg^-1)灌服，2 mL/只；对照组给予等量生理盐水，6周后取材。用免疫组化法观察JAM-1，JAM-2在癌细胞、淋巴管及血管的表达。结果：对照组JAM-1阳性表达的肿瘤细胞吸光度(A)549.90，实验组340.55，P<0.05；JAM-2阳性表达弱。对照组JAM-1和JAM-2阳性表达的血管数密度分别为2.33和1.34，实验组分别为1.09和0.9。对照组JAM-1和JAM-2阳性表达的淋巴管数密度分别为2.23和1.88，实验组分别为0.99和0.79；两组间的差异均为P<0.05。结论：人参皂苷Rh₂通过下调JAM在肿瘤细胞的表达，抑制肿瘤组织血管及淋巴管的生成，进而抑制肿瘤生长。     

后海穴区的血管及淋巴管分布研究

目的 探讨穴区内血管、淋巴管与经络腧穴的关系。方法 36羽鸡采用ABS血管铸型、微血管灌注组织切片及淋巴灌注方法。结果 后海穴的血液供应主要来源于髂内动脉、荐中动脉和肠系膜后动脉的分支,呈规律性的辐凑型;后海穴中轴结缔组织内的微血管致密,相互吻合形成血管网,并与腔上囊和泄殖腔的微血管形成网络连结,此区的淋巴管亦很丰富。结论 腧穴的实质应为驱体的结缔组织（包括相关的血管、淋巴管、神经）及内脏器官等多种结构的主体复合构筑。     

胰岛素固体脂质纳米粒的制备及其理化性质研究

 目的 制备胰岛素固体脂质纳米粒并考察其理化性质。方法 采用溶剂扩散法制备胰岛素固体脂质纳米粒,考察制备过程中加入多聚阴离子对纳米粒粒径、表面电位和药物包封率的影响;研究载药纳米粒的体外释放特性;荧光标记固体脂质纳米粒经大鼠口服给药,由荧光倒置显微镜观察血液和淋巴液中的荧光强度。结果胰岛素固体脂质纳米粒的平均粒径为(388.6±143.5)nm,水相中加入三聚磷酸钠对纳米粒粒径无明显影响,而表面电位下降,药物包封率明显增加;胰岛素固体脂质纳米粒最初1 h快速释放了药物包封总量的35.63％,随后以接近每小时1.5％的速度释放,呈明显的缓释特征,24 h体外累积释放量为药物包封量的67.30％;固体脂质纳米粒经大鼠口服研究发现,0.5 h时淋巴液中的荧光强度明显高于相同时间血液中的荧光强度。结论 采用溶剂扩散法制备得到的胰岛素固体脂质纳米粒,具有明显的药物缓释作用;通过调节纳米粒表面电位,可明显提高药物的包封率;固体脂质纳米粒口服给药,具有明显的纳米粒整体淋巴吸收特性。     

补肾活血浸膏的舒张血管作用及其机理研究

目的:通过观察补肾活血浸膏对豚鼠肠系膜微血管、大鼠胸主动脉环、门静脉环及其血浆的NO、血管的NO和NOS、cNOS、iNOS的影响,研究本方的舒张血管作用及其效应机制.方法:去甲肾上腺素致豚鼠肠系膜微血管收缩研究其整体的舒张血管作用;观察药物对苯肾上腺素收缩离体大鼠胸腔主动脉环或静脉环的作用,以及在预加优降糖或普萘洛尔或去血管内皮后其作用的影响;硝酸还原酶法测定给予药物后大鼠血浆和血管的NO及血管NOS、cNOS、iNSO的含量变化.结果:补肾活血浸膏有扩张去甲肾上腺素致豚鼠肠系膜微血管收缩的作用;松弛苯肾上腺素引起的离体大鼠胸腔主动脉环或静脉环的收缩作用,预加优降糖仍然有松弛作用.然而对预加普萘洛尔后补肾活血浸膏剂量低时保持舒张血管作用,剂量增加时反而引起收缩血管作用,大鼠胸腔主动脉环去内皮后药物无松弛作用,反而引起收缩作用;补肾活血浸膏高、低剂量组均能升高血浆NO水平,但只有高剂量组有显著性差异(P＜0.01);高、低剂量组均能显著性升高大鼠主动脉NO(P＜0.001,P＜0.05);高剂量组显著性升高NOS(P＜0.05)和cNOS(P＜0.001),低剂量组有升高NOS作用,但无显著性差异,对cNOS有显著性升高作用.结论:补肾活血浸膏的舒张血管作用机制与血管内皮释放NO和促进NOS、cNOS合成有关.