Bleomycin restricts the glycolysis of lymphatic endothelial cells by inhibiting dimeric PKM2 formation: A novel mechanism for lymphatic malformation treatment.

Glycolysis is activated in lymphatic endothelial cells and contributes to the development of lymphatic malformations (LMs). Bleomycin (BLM) is the most wildly used sclerosant for LMs, but its mechanisms are unclear. Here, our data showed that BLM suppressed the glycolysis of human dermal lymphatic endothelial cells (HDLECs) via inhibiting the expression and nucleus translocation of pyruvate kinase M2 isoform (PKM2) and inhibited dimeric PKM2 formation. Furthermore, the proliferation of LM lesions was inhibited by BLM through the down-regulation of nuclear PKM2 in the rat model. Additionally, PKM2, especially the nuclear PKM2 along with Ki-67, was inhibited in the lymphatic vessels of BLM-treated LMs. Our findings provide a new molecular mechanism of BLM in LM sclerotherapy treatment.

Drug Eluting Embolization Particles for Permanent Contraception.

Medical technology that blocks the fallopian tubes nonsurgically could increase access to permanent contraception and address current unmet needs in family planning. To achieve total occlusion of the fallopian tube via scar tissue formation, acute trauma to the tubal epithelium must first occur followed by a sustained and ultimately fibrotic inflammatory response. Here, we developed drug-eluting fiber-based microparticles that provide tunable dose and release of potent sclerosing agents. This fabrication strategy demonstrates high encapsulation of physicochemically diverse agents and the potential for scalable manufacturing by utilizing free-surface electrospinning to generate material for fiber micronization. Manipulation of nanofiber formulation such as drug loading, drug hydrophobicity, polymer hydrophobicity, and crystallinity allowed for modulation of the sustained release properties of our fiber microparticles. We assessed various fibrous microparticle formulations in vivo using a newly developed and validated guinea pig model for contraception. We found that fiber microparticles with bolus release doxycycline effectively elicited acute trauma and those formulated with highly loaded phenyl benzoate caused sustained inflammation in the target organs. The demonstrated potency of these electrospun microparticles, as well as their embolic size and shape, suggests potential for proximal agglomeration and inflammatory activity in the fallopian tubes following transcervical delivery.

Impact of Factors Secreted by Tumor Cells on Response of Pleural Mesothelial Cells to Different Sclerosing Agents in an In Vitro Model.

BACKGROUND Chemical pleurodesis is one of the major therapeutic options for patients with recurrent malignant pleural effusion. Mesothelial cells are considered to play a pivotal role in the response to different chemical compounds (sclerosants) used for pleurodesis. Malignant cells might have an impact on the mesothelial response to applied sclerosing agents and, in consequence, on the efficacy of pleurodesis. We aimed to evaluate the impact of cancer cell paracrine on mesothelial cell response to different sclerosing agents. MATERIAL AND METHODS The study used mesothelial cell (MeT-5A) cultures stimulated with sclerosing agents (talc, doxycycline, iodopovidone, and TGF-ß for 24 h) in the presence or absence of supernatants from adenocarcinoma cultures (HCC827). The mesothelial mRNA expression and protein levels of IL-6, IL-8, and TGF-ß was assessed. Further, lung fibroblasts were cultured with and without cell supernatants from previously established cell cultures for 24 h. Then, concentration of soluble collagen was evaluated in culture supernatants. RESULTS The exposure of mesothelial cells to sclerosants decreased the concentration of IL-6 and IL-8 protein. The addition of mediators secreted by adenocarcinoma altered the inflammatory response of the mesothelial cells to sclerosing agents. IL-8 concentration in cultures stimulated with talc and adenocarcinoma supernatant was higher compared to cultures stimulated with talc only. The exposure of lung fibroblasts to supernatant from mesothelial cell (with or without adenocarcinoma) did not affect collagen secretion. CONCLUSIONS An addition of soluble factors produced by adenocarcinoma altered the inflammatory response of the pleural mesothelial cells after stimulation with sclerosing agents. Our observations suggest that the tumor paracrine effect affects biological pathways of pleurodesis.

LIPIODOL reduces the lytic activity of detergent sclerosants in vitro.

OBJECTIVES: Contrast agents are used widely in the interventional setting and in particularly in the management of vascular anomalies and have also been used in combination with sclero-embolic agents. There is limited information on the interaction of contrast agents with sclerosant agents when used as mixtures. The aim of this study was to determine the effect of mixing radiological contrast agents with detergent sclerosants and measuring the effect on change in lytic activity of detergent sclerosants in vitro and by proxy the change in potency. METHODS: Red blood cell lysis was assessed following the incubation of two commonly used contrast agents, LIPIODOL® and ULTRAVIST®, mixed with detergent sclerosants, FIBROVEIN®, sodium tetradecyl sulfate (STS), and AETHOXYSKLEROL®, polidocanol (POL). RESULTS: The density of both contrast agents was higher than STS and POL and neither of the detergent sclerosants were miscible in LIPIODOL. LIPIODOL on its own caused cell lysis (1.01%, p < 0.05) whereas ULTRAVIST did not. Fifty per cent cell lysis for sclerosant and LIPIODOL mix occurred at concentrations of: 0.041% (2.4 times greater than the control, p < 0.05) and 0.08% (3.6 times greater than the control, p = 0.06) for STS and POL, respectively. CONCLUSIONS: LIPIODOL, when mixed with sclerosant detergents (ratio 1:1) causes a reduction in the lytic activity of sclerosants and this effect was statistically significant and most prominent in lower sclerosant concentration mixtures.

Primary human mesothelial cell culture in the evaluation of the inflammatory response to different sclerosing agents used for pleurodesis.

The mechanisms of chemical pleurodesis are still not fully explained. We aimed to evaluate the feasibility of using primary biopsy-derived human mesothelial cells to establish an in vitro culture and to assess the response of pleural mesothelial cells to different sclerosing agents. Talc, povidone-iodine, doxycycline, and TGF-ß were used at different doses to stimulate pleural mesothelial cells. After 6 and 24 h, mRNA expression of interleukin (IL)-1ß, IL-6, IL-8, TGF-ß, MCP-1, IL-17A, and MMP9 was measured in cultured cells, and the protein level of IL-1ß, IL-6, and IL-8 was measured in the culture supernatant. The most pronounced response was observed after talc exposure. It was expressed as an increase in IL-1ß concentration in culture supernatant after 24 h of higher talc dose stimulation compared to 6 h of stimulation (17.14 pg/ml [11.96-33.32 pg/ml] vs. 1.84 pg/ml [1.81-1.90 pg/ml], p = 0.02). We showed that culture pleural mesothelial cells isolated from pleura biopsy specimens is feasible. Inflammatory responses of mesothelial cells to different sclerosants were highly variable with no consistent pattern of mesothelium reaction neither in terms of different sclerosing agents nor in the time of the most significant reaction. We demonstrated that pro-inflammatory mesothelial response includes an increase in IL-1ß mRNA expression and protein production. This may suggest the role of IL-1ß in the formation and maintenance of the inflammatory response during pleurodesis.

Evaluation of the efficacy of foam sclerosant after addition of glycerine on human great saphenous vein: histological and immunohistochemical study.

INTRODUCTION: Several treatment modalities have been postulated to improve the efficacy of varicose vein treatment. Addition of glycerine to the sclerosing material has been documented to increase its viscosity and subsequently prolong the duration of stability, in addition to the direct sclerosing effect of glycerine. This histological and immunohistochemical study investigated the efficacy of addition of glycerine 72% to sclerotherapy on the human varicose vein. METHODS: After surgical stripping of great saphenous veins, three equal segments were resected between two clamps. Specimen 1 was injected with saline only, specimen 2 was exposed to foam sclerosant 2%, and specimen 3 was exposed to a mixture of foam sclerosant 2% and glycerine 72%. All segments were left for 5min. Vein segments were then processed for histological and immunohistochemical study. RESULTS: Microscopically, haematoxylin and eosin-stained specimen 1 showed endothelial swelling, cytoplasmic eosinophilia and pyknotic nuclei. The media showed sarcoplasm vacuolisation and necrosis. Specimen 3 showed hypereosinophilic sarcoplasm of the smooth muscle fibres. Oedema was less evident, with a relative decrease in the thickness of the wall compared with specimen 2. Immunohistochemically, the expression of smooth muscle actin was weak in specimen 3 compared with specimens 1 and 2. Expression of CD31 antibody was much reduced in specimen 2 which showed conserved islands of endothelial cells. By contrast, there was a complete loss of endothelial cells in specimen 3. CONCLUSION: Addition of glycerine 72% to foam sclerosant has a more damaging effect on human vein wall.

Foam-in-vein: A review of rheological properties and characterization methods for optimization of sclerosing foams.

Varicose veins are chronic venous defects that affect >20% of the population in developed countries. Among potential treatments, sclerotherapy is one of the most commonly used. It involves endovenous injection of a surfactant solution (or foam) in varicose veins, inducing damage to the endothelial layer and subsequent vessel sclerosis. Treatments have proven to be effective in the short-term, however recurrence is reported at rates of up to 64% 5-year post-treatment. Thus, once diagnosed with varicosities there is a high probability of a permanently reduced quality of life. Recently, foam sclerotherapy has become increasingly popular over its liquid counterpart, since foams can treat larger and longer varicosities more effectively, they can be imaged using ultrasound, and require lower amounts of sclerosing agent. In order to minimize recurrence rates however, an investigation of current treatment methods should lead to more effective and long-lasting effects. The literature is populated with studies aimed at characterizing the fundamental physics of aqueous foams; nevertheless, there is a significant need for appropriate product development platforms. Despite successfully capturing the microstructural evolution of aqueous foams, the complexity of current models renders them inadequate for pharmaceutical development. This review article will focus on the physics of foams and the attempts at optimizing them for sclerotherapy. This takes the form of a discussion of the most recent numerical and experimental models, as well as an overview of clinically relevant parameters. This holistic approach could contribute to better foam characterization methods that patients may eventually derive long term benefit from.

Sirolimus and propranolol inhibit endothelial proliferation while detergent sclerosants induce endothelial activation, microparticle release and apoptosis in vitro.

OBJECTIVES: To investigate the effects of detergent sclerosants, sodium tetradecyl sulphate and polidocanol, on endothelial cell activation and microparticle release and the effects of detergent sclerosants, sirolimus and propranolol, on apoptosis in vitro. METHODS: Cultured human umbilical vein endothelial cells and murine haemangioendothelioma (EOMA) cell lines were incubated with different concentrations of sodium tetradecyl sulphate and polidocanol, as well as sirolimus and propranolol. Endothelial activation was assessed using flow cytometry for CD62e (E-Selectin), CD54 (ICAM-1), CD105 (endoglin), CD144 (VE-Cadherin), CD146 (MCAM) and the release of endothelial microparticles. Cell proliferation was assessed using [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] and carboxyfluorescein succinimidyl ester assays. Apoptosis was assessed using flow cytometry for lactadherin/propidium iodide staining and for Caspase-3 expression. RESULTS: Sublytic concentrations of sodium tetradecyl sulphate and polidocanol (0.075%-0.3%) increased the expression of the activation markers CD62e and CD54. The expression of CD105 decreased in sclerosant treated cultured human umbilical vein endothelial cells. Both sodium tetradecyl sulphate and polidocanol induced the release of endothelial microparticles. All agents inhibited cell proliferation. Sodium tetradecyl sulphate and polidocanol-induced apoptosis as evidenced by increased phosphatidylserine exposure and caspase-3 expression, whereas sirolimus and propranolol increased caspase-3 expression only. CONCLUSION: Sublytic concentrations of detergent sclerosants induce endothelial activation and the release of endothelial microparticles. All agents were anti-proliferative in EOMA cell lines, with sodium tetradecyl sulphate and polidocanol inducing cellular apoptosis.

PI3K Catalytic Subunits α and ß Modulate Cell Death and IL-6 Secretion Induced by Talc Particles in Human Lung Carcinoma Cells.

Hydrated magnesium silicate (or "talc" particles) is a sclerosis agent commonly used in the management of malignant pleural effusions, a common symptom of metastatic diseases, including lung cancers. However, the direct effects of talc particles to lung carcinoma cells, which can be found in the malignant pleural effusion fluids from patients with lung cancer, are not fully understood. Here, we report a study of the signaling pathways that can modulate the cell death and IL-6 secretion induced by talc particles in human lung carcinoma cells. We found that talc-sensitive cells have higher mRNA and protein expression of PI3K catalytic subunits α and ß. Further experiments confirmed that modulation (inhibition or activation) of the PI3K pathway reduces or enhances cellular sensitivity to talc particles, respectively, independent of the inflammasome. By knocking down specific PI3K isoforms, we also confirmed that both PI3Kα and -ß mediate the observed talc effects. Our results suggest a novel role of the PI3K pathway in talc-induced cell death and IL-6 secretion in lung carcinoma cells. These cellular events are known to drive fibrosis, and thus further studies of the PI3K pathway may provide a better understanding of the mechanisms of talc sclerosis in the malignant pleural space.

In vitro and ex vivo evaluation of the biological performance of sclerosing foams.

Since the first reports on foam sclerotherapy, multiple studies have been conducted to determine the physical properties and behavior of foams, but relatively little is known about their biological effects on the endothelial cells lining the vessel wall. Moreover, a systematic comparison of the biological performance of foams produced with different methods has not been carried out yet. Herein, a 2D in vitro method was developed to compare efficacy of commercially available polidocanol injectable foam (PEM, Varithena) and physician-compounded foams (PCFs). Endothelial cell attachment upon treatment with foam was quantified as an indicator of therapeutic efficacy, and was correlated with foam physical characteristics and administration conditions. An ex vivo method was also developed to establish the disruption and permeabilisation of the endothelium caused by sclerosing agents. It relied on the quantitation of extravasated bovine serum albumin conjugated to Evans Blue, as an indicator of endothelial permeability. In our series of comparisons, PEM presented a greater overall efficacy compared to PCFs, across the different biological models, which was attributed to its drainage dynamics and gas formulation. This is consistent with earlier studies that indicated superior physical cohesiveness of PEM compared to PCFs.

Particle size, distribution, and behavior of talc preparations: within the United States and beyond.

PURPOSE OF REVIEW: Talc remains a common sclerosant utilized for pleurodesis. However, the use of talc has documented complications and debate has persisted regarding the safety of talc as well as the differences in talc preparations available throughout the world. We sought to describe an up-to-date review of talc preparations available and the impact these preparations may have on the safety profile of talc. RECENT FINDINGS: Within laboratory-based examinations, talc particle size available within the United States appears to be more consistent with prior reported 'safe' particle sizes. The presence of talc within protein-based solutions appears to modify the overall milieu of the solution and likely results in particle aggregation. SUMMARY: The use of talc remains well accepted for pleurodesis as evidenced by inclusion by multiple guidelines. The medical fields' current understanding of talc and its basic interactions within the pleural space remain limited. Multiple questions related to the pleural space and pleurodesis remain unanswered.

Fibrosing/Sclerosing Lesions of the Mediastinum: A Review.

Fibrosing lesions of the mediastinum represent a small but challenging group of lesions that range in etiology from infectious to idiopathic to neoplastic. The diagnosis of such lesions becomes more challenging in the setting of mediastinoscopic biopsies. In addition, over the years, there has been further accumulation of knowledge of the clinical aspects of these lesions that needs to be incorporated into their evaluation. Therefore, it is essential that in the general evaluation of these fibrosing processes, one not only carefully examines the histopathologic features of the lesion, that of a fibroinflammatory process with the appropriate histochemical and immunohistochemical studies, but also carefully evaluates the clinical presentation and imaging findings. Needless to say, as will be illustrated in this review, determining a definitive unequivocal diagnosis on a small mediastinoscopic biopsy may be difficult, and often one needs to provide guidance on the perspective of the histologic features present. In some cases, mainly tumoral conditions with extensive fibrosis, a conclusive diagnosis can be made; however, it is those cases in which the extensive fibrosis is the only histopathologic feature where more appropriate guidance is required. While this review will focus more on the non-neoplastic fibroinflammatory lesions of the mediastinum, within the discussion of differential diagnoses, we will discuss some neoplastic conditions that commonly show extensive fibrosing features.

Intravascular and intraparenchymatous hepatic segmentary sclerosis.

PURPOSE: To evaluate the morphological effects of injected sclerosing agents into the liver. METHODS: This study was performed on twenty dogs, distributed into five groups: Group 1 (n = 5) - control, Group 2 (n = 5) - injection of 50% glucose solution inside hepatic parenchyma and animals followed during seven days, Group 3 (n = 10) - injection of ethanol inside hepatic parenchyma and animals distribution into two subgroups Subgroup 3A (n = 5) - followed during 24 hours and subgroup 3B (n = 5) - followed during seven days (group 3B), Group 4 (n = 5) - ethanol injection inside left portal vein branch and followed during 24 hours. Livers were macroscopically evaluated, submitted to hepatic arteriography and portography, then histology. RESULTS: All animals in Group 4 died within 23 hours due to diffuse hepatic necrosis. The animals of groups 2 and 3 had a satisfactory evolution. Fibrosis formed in the segment reached by the sclerosant solution and interruption of the contrast flow injected into the portal system. CONCLUSION: Intrahepatic parenchymal ethanol injection is well tolerated and causes sclerosis restricted to a specific segment; however, intraportal ethanol injection causes massive hepatic necrosis and can lead to death.

Intravascular and intraparenchymatous hepatic segmentary sclerosis

Abstract Purpose: To evaluate the morphological effects of injected sclerosing agents into the liver. Methods: This study was performed on twenty dogs, distributed into five groups: Group 1 (n = 5) - control, Group 2 (n = 5) - injection of 50% glucose solution inside hepatic parenchyma and animals followed during seven days, Group 3 (n = 10) - injection of ethanol inside hepatic parenchyma and animals distribution into two subgroups Subgroup 3A (n = 5) - followed during 24 hours and subgroup 3B (n = 5) - followed during seven days (group 3B), Group 4 (n = 5) - ethanol injection inside left portal vein branch and followed during 24 hours. Livers were macroscopically evaluated, submitted to hepatic arteriography and portography, then histology. Results: All animals in Group 4 died within 23 hours due to diffuse hepatic necrosis. The animals of groups 2 and 3 had a satisfactory evolution. Fibrosis formed in the segment reached by the sclerosant solution and interruption of the contrast flow injected into the portal system. Conclusion: Intrahepatic parenchymal ethanol injection is well tolerated and causes sclerosis restricted to a specific segment; however, intraportal ethanol injection causes massive hepatic necrosis and can lead to death.

Comparing Electrical Stimulation With and Without Ultrasound Guidance for Phenol Neurolysis to the Musculocutaneous Nerve.

BACKGROUND: Ultrasound guidance is increasingly being used for neurolytic procedures that have traditionally been done with electrical stimulation (e-stim) guidance alone. Ultrasound visualization with e-stim-guided neurolysis can potentially allow adjustments in injection protocols that will reduce the volume of neurolytic agent needed to achieve clinical improvement. OBJECTIVE: This study compared e-stim only to e-stim with ultrasound guidance in phenol neurolysis of the musculocutaneous nerve (MCN) for elbow flexor spasticity. We also evaluated the ultrasound appearance of the MCN in this population. DESIGN: Retrospective review. SETTING: University hospital outpatient clinic. PARTICIPANTS: Adults (N = 167) receiving phenol neurolysis to the MCN for treatment of elbow flexor spasticity between 1997 and 2014 and adult control subjects. METHODS: For each phenol injection of the MCN, the method of guidance, volume of phenol injected, technical success, improved range of motion at the elbow postinjection, adverse effects, reason for termination of injections, and details of concomitant botulinum toxin injection were recorded. The ultrasound appearance of the MCN, including nerve cross-sectional area and shape, were recorded and compared between groups. MAIN OUTCOME MEASURES: The volume of phenol injected and MCN cross-sectional area and shape as demonstrated by ultrasound. RESULTS: The addition of ultrasound to e-stim-guided phenol neurolysis was associated with lower doses of phenol when compared to e-stim guidance alone (2.31 mL versus 3.69 mL, P < .001). With subsequent injections, the dose of phenol increased with e-stim guidance (P < .001), but not with e-stim and ultrasound guidance (P = .95). Both methods of guidance had high technical success, improved ROM at elbow postinjection, and low rates of adverse events. In comparing the ultrasound appearance of the MCN in patients with spasticity to that of normal controls, there was no difference in the cross-sectional area of the nerve, but there was more variability in shape. CONCLUSIONS: Combined e-stim and ultrasound guidance during phenol neurolysis to the MCN allows a smaller volume of phenol to be used for equal effect, both at initial and repeat injection. The MCN shape was more variable in individuals with spasticity; this should be recognized so as to successfully locate the nerve to perform neurolysis. LEVEL OF EVIDENCE: IV.

Vascular sclerosing effects of bleomycin on cutaneous veins: a pharmacopathologic study on experimental animals.

BACKGROUND:: Varicose veins and the complications of venous disease are common disorders in humans. OBJECTIVE:: To study the effects of bleomycin as a potential new sclerosing agent and its adverse events in treating varicose veins. METHODS:: Bleomycin-loaded liposomes 0.1ml was injected in the dorsal ear veins of white New Zealand rabbits. Sodium tetradecyl sulfate was used as a positive control. Normal saline was used as negative control. The blood vessels of the treated ears were photographed before and at one hour and two, eight and 45 days after treatment. Biopsies from the treated areas were obtained for histological examination. Blood samples were collected to determine any possible toxicity. RESULTS:: Bleomycin by itself was ineffective; therefore, liposomes were used as a vector to deliver bleomycin to the vein lumen. Subsequently, bleomycin started showing its sclerosing effects. Toxicity monitoring showed no apparent hematologic, pulmonary, hepatic or renal toxicities. This study revealed that bleomycin induced vasculitis, which led to vascular occlusion, which was observed on day 1 and day 8. No bleomycin-related injury was noted by histopathological examination of lung sections. The calculation of the lung/body weight coefficient indicated that edema was present in the experimental groups compared with the negative and positive controls. STUDY LIMITATIONS:: Relatively small number of experimental animals used. CONCLUSIONS:: This study showed that bleomycin-loaded liposomes were able to induce vasculitis and vascular occlusion without any toxicity or complications. It might be useful, hence, to treat patients suffering from Varicose veins and other ectatic vascular diseases with this agent.

Chitosan-doxycycline hydrogel: An MMP inhibitor/sclerosing embolizing agent as a new approach to endoleak prevention and treatment after endovascular aneurysm repair.

The success of endovascular repair of abdominal aortic aneurysms remains limited due to the development of endoleaks. Sac embolization has been proposed to manage endoleaks, but current embolizing materials are associated with frequent recurrence. An injectable agent that combines vascular occlusion and sclerosing properties has demonstrated promise for the treatment of endoleaks. Moreover, the inhibition of aneurysmal wall degradation via matrix metalloproteinases (MMPs) may further prevent aneurysm progression. Thus, an embolization agent that promotes occlusion, MMP inhibition and endothelial ablation was hypothesized to provide a multi-faceted approach for endoleak treatment. In this study, an injectable, occlusive chitosan (CH) hydrogel containing doxycycline (DOX)-a sclerosant and MMP inhibitor-was developed. Several CH-DOX hydrogel formulations were characterized for their mechanical and sclerosing properties, injectability, DOX release rate, and MMP inhibition. An optimized formulation was assessed for its short-term ability to occlude blood vessels in vivo. All formulations were injectable and gelled rapidly at body temperature. Only hydrogels prepared with 0.075M sodium bicarbonate and 0.08M phosphate buffer as the gelling agent presented sufficient mechanical properties to immediately impede physiological flow. DOX release from this gel was in a two-stage pattern: a burst release followed by a slow continuous release. Released DOX was bioactive and able to inhibit MMP-2 activity in human glioblastoma cells. Preliminary in vivo testing in pig renal arteries showed immediate and delayed embolization success of 96% and 86%, respectively. Altogether, CH-DOX hydrogels appear to be promising new multifunctional embolic agents for the treatment of endoleaks. STATEMENT OF SIGNIFICANCE: An injectable embolizing chitosan hydrogel releasing doxycycline (DOX) was developed as the first multi-faceted approach for the occlusion of blood vessels. It combines occlusive properties with DOX sclerosing and MMP inhibition properties, respectively known to prevent recanalization process and to counteract the underlying pathophysiology of vessel wall degradation and aneurysm progression. After drug release, the biocompatible scaffold can be invaded by cells and slowly degrade. Local DOX delivery requires lower drug amount and decreases risks of side effects compared to systemic administration. This new gel could be used for the prevention or treatment of endoleaks after endovascular aneurysm repair, but also for the embolization of other blood vessels such as venous or vascular malformations.

Vascular sclerosing effects of bleomycin on cutaneous veins: a pharmacopathologic study on experimental animals

Abstract: Background: Varicose veins and the complications of venous disease are common disorders in humans. Objective: To study the effects of bleomycin as a potential new sclerosing agent and its adverse events in treating varicose veins. Methods: Bleomycin-loaded liposomes 0.1ml was injected in the dorsal ear veins of white New Zealand rabbits. Sodium tetradecyl sulfate was used as a positive control. Normal saline was used as negative control. The blood vessels of the treated ears were photographed before and at one hour and two, eight and 45 days after treatment. Biopsies from the treated areas were obtained for histological examination. Blood samples were collected to determine any possible toxicity. Results: Bleomycin by itself was ineffective; therefore, liposomes were used as a vector to deliver bleomycin to the vein lumen. Subsequently, bleomycin started showing its sclerosing effects. Toxicity monitoring showed no apparent hematologic, pulmonary, hepatic or renal toxicities. This study revealed that bleomycin induced vasculitis, which led to vascular occlusion, which was observed on day 1 and day 8. No bleomycin-related injury was noted by histopathological examination of lung sections. The calculation of the lung/body weight coefficient indicated that edema was present in the experimental groups compared with the negative and positive controls. Study limitations: Relatively small number of experimental animals used. Conclusions: This study showed that bleomycin-loaded liposomes were able to induce vasculitis and vascular occlusion without any toxicity or complications. It might be useful, hence, to treat patients suffering from Varicose veins and other ectatic vascular diseases with this agent.

Mechanochemical ablation causes endothelial and medial damage to the vein wall resulting in deeper penetration of sclerosant compared with sclerotherapy alone in extrafascial great saphenous vein using an ex vivo model.

BACKGROUND: Nonthermal, tumescentless devices are the next generation of minimally invasive devices to treat varicose veins. We aimed to investigate the effects of mechanochemical ablation (MOCA) using ClariVein (Vascular Insights, Quincy, Mass) on ex vivo great saphenous vein with histology and immunofluorescent staining. METHODS: Extrafascial great saphenous veins were harvested during surgery for varicose veins and were treated ex vivo for 10 to 11 minutes with either liquid sclerotherapy or the use of ClariVein, with and without 3% sodium tetradecyl sulfate. Veins were sectioned and subjected to hematoxylin and eosin staining and immunofluorescent staining for endothelial and smooth muscle cell markers (CD31 and α-actin) to assess overall damage and cell death in the vein wall compared with control sections. RESULTS: Histologic observations confirmed intimal damage from ClariVein, as has been previously shown; however, medial damage was also evident, which was not observed in control or liquid sclerotherapy sections. Immunofluorescent staining in the three sections studied showed a 42% decrease in CD31 staining and 27% mean reduction in α-actin staining up to a depth of 300 µm with liquid sclerotherapy. This cytotoxic effect was significantly enhanced by MOCA with a reduction in CD31 staining just above 60% and a 46% mean decrease in α-actin staining noted up to a depth of 300 µm. Far greater reductions in staining compared with sclerotherapy were observed up to a depth of 600 µm. CONCLUSIONS: MOCA using 3% sodium tetradecyl sulfate increases the penetration of the sclerosant and its effect into the vein wall and shows superior rates of tissue destruction compared with liquid sclerotherapy alone. In this model, it appears not solely to damage the endothelium but also to shear the medial layer, creating small lesions into which sclerosant can flow and exert its cytotoxic effect.