Varicose veins: role of mechanotransduction of venous hypertension

Clinical evidence and rationale of mesoglycan to treat chronic venous disease and hemorrhoidal disease: a narrative review

Chronic venous disease (CVD) and hemorrhoidal disease (HD) are among the most common vascular diseases in the world, with CVD affecting 22-41% of the population in Europe and HD having a point prevalence of 11-39%. The burden is substantial in terms of the effect of symptoms on patients' health-related quality of life (HRQoL) and direct/indirect medical costs. Treatment begins with lifestyle changes, compression in CVD and topical therapies in HD, and escalates as needed through oral therapies first and eventually to surgery for severe disease. CVD and HD share etiological features and pathological changes affecting the structure and function of the tissue extracellular matrix. Mesoglycan, a natural glycosaminoglycan (GAG) preparation composed primarily of heparan sulfate and dermatan sulfate, has been demonstrated to positively impact the underlying causes of CVD and HD, regenerating the glycocalyx and restoring endothelial function, in addition to having antithrombotic, profibrinolytic, anti-inflammatory, antiedema and wound-healing effects. In clinical trials, oral mesoglycan reduced the severity of CVD signs and symptoms, improved HRQoL, and accelerated ulcer healing. In patients with HD, mesoglycan significantly reduced the severity of signs and symptoms and the risk of rectal bleeding. In patients undergoing excisional hemorrhoidectomy, adding mesoglycan to standard postoperative care reduced pain, improved HRQoL, reduced incidence of thrombosis, and facilitated an earlier return to normal activities/work, compared with standard postoperative care alone. The clinical effects of mesoglycan in patients with CVD or HD are consistent with the agent's known mechanisms of action.

A novel view to varicose veins pathogenesis: Proteomic profiling suggests a pivotal role of extracellular matrix degradation

INTRODUCTION

Although morphological and anatomical studies indicate that venous wall weakening and subendothelial fibrosis characterize varicose veins (VV), the pathogenesis of VV remains poorly understood. The aim of this study is to obtain protein expression profiles in patients with VV and thereby get a step closer to understanding the pathogenesis of VV.

METHODS

Specimens were obtained from total of 10 patients, that is, from 5 patients undergoing VV surgical stripping and from 5 non-VV patients undergoing bypass surgery. Specimens were collected from the same layers of venous wall. Proteins were extracted from each specimen and analyzed by ion mobility spectrometry (IMS-MS). In total, 1387 were identified and 486 proteins were identified in all samples. From these, 15 proteins were differentially expressed between VV and non-VV samples (p < .05) and 12 of these showed a fold change >1.5.

RESULTS

Interestingly, among the differentially expressed proteins, only two proteins were significantly increased in the VV tissue, that is, GAPDH (p = .028, fold change 2.74), where several proteins involved in maintaining the homeostasis in the extracellular matrix, that is, the CXXC zinc finger protein 5 (CXXC5) and nucleoporin (SEH1) were prominently downregulated (p = .049, fold change 37.8, and p = .040, fold change 3.46). The downregulation in protein expression of CXXC5 and SEH1 as well as upregulation of GAPDH were validated by Western blotting.

CONCLUSION

The identified differentially expressed proteins suggest an altered profile of the connective tissue proteins as well as an increased proteolytic enzyme activity which both may be central in the pathophysiology of varicose veins.

What is the relationship of varicose vein pathogenesis with collagen fibers?

Aims and Background

In this study, the densities of collagen 1 and collagen 4, which are an effective vascular component in the remodelling of varicose veins, were investigated.

Materials and Methods

The study included primary varicose vein samples of 20 patients and vein samples of 20 healthy controls. Immunohistochemical staining was performed using collagen 1 and collagen 4 antibodies. Histochemical staining was performed using Masson Trichrome.

Results

In the immunohistochemical analysis of varicose samples, collagen 1 immunostaining was negative in 17 cases (85%) and positive in 3 cases (15%). In healthy venous tissue samples, collagen 1 immunostaining was negative in 12 cases (60%) and positive in 8 cases (40%). There was no statistically significant difference between both groups concerning collagen 1 immunostaining (p > 0.05). In varicose samples, collagen 4 immunostaining was negative in 4 cases (20%) and positive in 16 cases (80%). In healthy venous tissue samples, collagen 4 immunostaining was negative in 13 cases (65%) and positive in 7 cases (35%). Statistical comparison of healthy veins and varicose veins concerning collagen 4 immunostaining showed a significant difference (p = 0.03). In the histochemical analysis of varicose samples, Masson Trichrome staining was negative in 4 cases (20%) and positive in 16 cases (80%). In healthy venous tissue samples, Masson Trichrome staining was negative in 18 cases (90%) and positive in 2 cases (10%). Statistical comparison of healthy veins and varicose veins concerning collagen 4 immunostaining showed a significant difference (p = 0.01).

Conclusion

The change in the density of collagen types plays an important role in vein wall remodeling.

Understanding Chronic Venous Disease: A Critical Overview of Its Pathophysiology and Medical Management

Chronic venous disease (CVD) is a multifactorial condition affecting an important percentage of the global population. It ranges from mild clinical signs, such as telangiectasias or reticular veins, to severe manifestations, such as venous ulcerations. However, varicose veins (VVs) are the most common manifestation of CVD. The explicit mechanisms of the disease are not well-understood. It seems that genetics and a plethora of environmental agents play an important role in the development and progression of CVD. The exposure to these factors leads to altered hemodynamics of the venous system, described as ambulatory venous hypertension, therefore promoting microcirculatory changes, inflammatory responses, hypoxia, venous wall remodeling, and epigenetic variations, even with important systemic implications. Thus, a proper clinical management of patients with CVD is essential to prevent potential harms of the disease, which also entails a significant loss of the quality of life in these individuals. Hence, the aim of the present review is to collect the current knowledge of CVD, including its epidemiology, etiology, and risk factors, but emphasizing the pathophysiology and medical care of these patients, including clinical manifestations, diagnosis, and treatments. Furthermore, future directions will also be covered in this work in order to provide potential fields to explore in the context of CVD.

A Comprehensive Review on Varicose Veins: Preventive Measures and Different Treatments

The purpose of this article was to review the different preventive measures and treatments for varicose veins disease. Varicose veins are tortuous, enlarged veins that are usually found in the lower extremities damages blood vessels leading to its painful swelling cause's blood clots, affecting people over increasing prevalence with age and affects the proficiency, productivity, and life quality of a person. Prolonged standing and obesity are the major reason for varicose vein disease. The mechanisms, prevention, risk factors, complications, and treatment of varicose veins are explained in this review. Various types of treatments such as endovascular, surgical, and herbal treatments improve quality of life and reduce the secondary complications of varicose veins. Besides these methods of treatments, varicose vein disease can be prevented by doing regular yoga/exercise and consumption of several fruits and vegetables such as Grapes, blackberries, avocados, ginger, and rosemary. Typically, varicose veins can be a benign process with several problems that can influence the life quality of an individual that can lead to potentially life-threatening complications. However, there are numerous surgical, endovascular, and chemical treatments that improve quality of life and decrease secondary complications of varicose veins. Patients with varicose veins should take an antioxidant medicament from the flavonoid groups to reduce the arterial blood pressure value, risk of atherosclerosis development, prevent thrombotic incidents.Key teaching pointsChronic venous disease is a pathological state of vein circulatory systems of the lower limbsProlonged standing and obesity are the major reason for varicose vein diseaseEndovascular, surgical, and herbal treatments improve quality of life and reduce the secondary complications of varicose veinsVenoactive drugs such as flavonoids, saponins, and others have a therapeutic effect on chronic venous disordersPhlebotropic drugs are semi-synthetic substances widely used in different states of chronic venous insufficiencyFood rich in phytoconstituents are more effective in varicose veins.

Role of mechanosignaling on pathology of varicose vein

Varicose veins are the most common vascular disease in humans. Veins have valves that help the blood return gradually to the heart without leaking blood. When these valves become weak, blood and fluid collect and pool by pressing against the walls of the veins, causing varicose veins. In the cardiovascular system, mechanical forces are important determinants of vascular homeostasis and pathological processes. Blood vessels are constantly exposed to a variety of hemodynamic forces, including shear stress and environmental strains caused by the blood flow. In varicose veins within the leg, venous blood pressure rises in the vein of the lower extremities due to prolonged standing, creating a peripheral tension in the vessel wall thereby causing mechanical stimulation of endothelial cells and vascular smooth muscle. Studies have shown that long-term increased exposure to vascular wall tension is associated with the overexpression of HIF-1α and HIF-2α and increased levels of MMP-2 and MMP-9, thereby reducing venous contraction and progressive venous dilatation, which is involved in the development of varicose veins. Following the expression of metalloproteinase, the expression of type 1 collagen increases, and the amount of type 3 collagen decreases. Therefore, collagen imbalance will cause the varicose veins to not stretch. Loss of structural proteins (type 3 collagen and elastin) in the vessel wall causes the loss of the biophysical properties of the varicose vein wall. This review article tries to elaborate on the effect of mechanical forces and sensors of these forces on the vascular wall in creating the mechanism of mechanosignaling, as well as the role of the onset of molecular signaling cascades in the pathology of varicose veins.

Hemodynamics mediated epigenetic regulators in the pathogenesis of vascular diseases

Endothelium of blood vessels is continuously exposed to various hemodynamic forces. Flow-mediated epigenetic plasticity regulates vascular endothelial function. Recent studies have highlighted the significant role of mechanosensing-related epigenetics in localized endothelial dysfunction and the regional susceptibility for lesions in vascular diseases. In this article, we review the epigenetic mechanisms such as DNA de/methylation, histone modifications, as well as non-coding RNAs in promoting endothelial dysfunction in major arterial and venous diseases, consequent to hemodynamic alterations. We also discuss the current challenges and future prospects for the use of mechanoepigenetic mediators as biomarkers of early stages of vascular diseases and dysregulated mechanosensing-related epigenetic regulators as therapeutic targets in various vascular diseases.

Symptoms in Dilating Venous Disease

Lower extremity venous diseases or insufficiency include clinically deteriorating conditions with morphological and functional alterations of the venous system, including venous hypertension, vascular wall structural abnormality, and venous valvar incompetency in association with an inflammatory process. In fact, the same pathophysiological processes are the main underlying mechanisms of other venous insufficiencies in different vascular territories such as Peripheral Varicose Vein (PVV), varicocele, Pelvic Varicosities or Congestion Syndrome (PCS) and Hemorrhoidal Disease (HD). Regarding the anatomical continuity of lower extremity venous system, urogenital system (pampiniform plexus in male and broad ligament and ovarian veins in female) and anorectal venous system, it is reasonable to expect common symptoms such as pain, burning sensation, pruritis, swelling, which arise directly from the involved tissue itself. High coexistence rate of PVV, varicocele/PCS and HD between each other underlines not only the same vascular wall abnormality as an underlying etiology but also the existence of common symptoms originating from the involved tissue in dilating venous disease. Accordingly, it might be reasonable to query the common symptoms of venous dilating disease in other venous vascular regions in patients with complaints of any particular venous territory.

Effect of a Peptide Construct on Differentiated Macrophage MMP-2 and MMP-9 Levels of Varicose Patients

BACKGROUND

The Matrix Metalloproteinase (MMPs) secreted from macrophages can affect the extracellular matrix remodeling process and improve varicose veins.

AIM

The aim of this study was to investigate the MMP-2 and MMP-9 gene expression and activity levels in the differentiated macrophages M2 of subjects with varicose veins, and to evaluate a peptide construct on their catalytic functions.

METHODS

The macrophages were differentiated from the monocytes using M-CSF. The MMP-2 and MMP-9 gene expression and activity levels were measured by RT-qPCR and Zymography techniques, respectively. A peptide construct (ESLCG) was predicted with bioinformatics tools, and was prepared for the study of enzyme functions as compared to Batimastat. Furthermore, the docking studies were obtained for the evaluation of interactions between peptide construct, Batimastat and enzyme 3D structures.

RESULTS

The results showed significant increases in MMP2 and MMP9 gene expression levels (P<0.001 and P<0.004, respectively) and gelatinolytic activities (P<0.001 and P<0.0001, respectively) in the macrophages. In agreement with the inhibitory effects of Batimastat, the peptide construct inhibited the MMP-2 and MMP-9 gelatinolytic activities up to 6.8 and 6.5 folds in the concentration of 150 µM. The docking analyses showed that the Lys187, Arg98, Leu49, Gly189, Leu190, Met97, Tyr53 and Phe57 residues of MMP-2 and the Leu187, His190, Glu402, His401, His405 and His411 residues of MMP-9 are interacted with the atoms of Batimastat and ESLCG peptide.

CONCLUSION

The ESLCG peptide may be applied as an inhibitor of MMP-2 and MMP-9 enzymes in the subjects with varicose veins.

Flow cytometric characterization of the saphenous veins endothelial cells in patients with chronic venous disease and in patients undergoing bypass surgery: an exploratory study

Recent findings have suggested that the primary factors for development of chronic venous disease (CVD), which commonly manifests as varicose veins (VV), are due to structural and biochemical modifications of the vessel wall. The aim of this exploratory study was to characterize by flow cytometry the endothelial cells (EC) mechanically extracted from the varicose saphenous veins (VSV) segments of patients submitted to VV surgery, and to compare the expression of cell surface molecules in these EC with that observed in the EC from the graft SV (GSV) of patients undergoing bypass surgery. EC were isolated from distal- (varicose trunk) and from proximal- (nearly normal) VSV segments of 30 patients submitted to VV surgery, and from proximal GSV segments of 20 patients submitted to bypass surgery (control group), using a mechanical method, and their immunophenotype was characterized by flow cytometry. EC were identified as being CD45^negCD146^brightCD31^bright, and analyzed for expression of activation-related (CD54, CD62E, CD106), procoagulant (CD142), and cell junction (CD31, CD146) molecules, and for the scavenger receptor, CD36. The EC harvested from the SV segments of CVD patients had lower expression of all the molecules evaluated, in comparison to controls; these differences were more evident for the EC isolated from the distal-VSV. The EC extracted from the proximal- and distal-VSV segments of the CVD patients also differ from each other, the first having lower levels of CD62E, CD106, CD142 and CD36. Groups did not match for gender and controls were heterogeneous concerning the underlying pathologies, which may have a confounding effect. Our study revealed that the EC isolated from varicose (distal) and nearly normal (proximal) VSV segments of the CVD patients differ phenotypically from each other, and from the EC of the control group. The VSV segments more affected by the CVD have the lowest expression of the studied markers. We hypothesize that CVD is associated with a decrease on the EC surface molecules, causing EC dysfunctionality. Further studies with a large number of gender-matched participants are needed, to confirm the results obtained in this exploratory study.

Associations between miR-661, miR-1202, lncRNA-HOTAIR, lncRNA-GAS5 and MMP9 in differentiated M2-macrophages of patients with varicose veins

BACKGROUND

The venous hypertension is suggested as the main cause of varicose disease. Some mediators and growth factors are known as the responsible of cellular events for the progression of venous perturbations. The aim of this study was to investigate non-coding (nc) RNA and MMP9 expression levels in macrophages differentiated from monocytes of patients with varicose veins.

METHODS

The monocytes were isolated from the whole blood samples by RosetteSep kit and were differentiated to macrophages M2 using M-CSF factor. The based on ncRNA-gene network, lncRNA-GAS5, lncRNA-HOTAIR, miRNA-661, miRNA-1202, and MMP9 were selected. The gene expression levels were measured by RT-qPCR technique.

RESULTS

Data showed that the MMP9 gene expression increased (P=0.003) while the GAS5, miRNA-661, and miRNA-1202 expression levels reduced significantly in the differentiated macrophages of patients (P=0.035, P=0.009, and P=0.015, respectively). Furthermore, the MMP9 gene expression levels were conversely related to the GAS5, HOTAIR, miRNA-661 and miRNA-1202 expression levels.

CONCLUSIONS

The results suggested that the lncRNA-GAS5, miRNA-661, miRNA-1202 and MMP9 are involved in varicose disease.

Iris varix: 10-year experience with 28 eyes

Purpose:

The purpose of this study is to describe the clinical characteristics, multimodality imaging findings, and clinical course of iris varices.

Methods:

Retrospective, noncomparative, observational case series of 28 eyes of 26 patients with iris varices, diagnosed between 2007 and 2017, has been used.

Results:

The mean (±SD) age was 58.3 ± 12.5 years (median 57.5, range 37–81). Patients were 57.7% male and 27% hypertensive. Varices were bilateral in two patients. The mean and median visual acuities were both 20/20 (range 20/16–20/40). Intraocular pressures were 16 mmHg (10–23 mmHg). Secondary glaucoma did not occur. The inferotemporal iris quadrant was affected in 75%. A single varix was seen in 64% and 36% appeared multiple. Varix orientation was radial in 57% and circumferential in 21%. Combined radial and circumferential varix orientation was noted in 18%. One had independent radial and circumferential varices in separate quadrants. A single episcleral sentinel blood vessel directed to the varix was present in 36%. Ultrasound biomicroscopy (UBM) showed a slightly increased mean iris thickness of 0.8 mm and multiple echolucent iris stromal vascular channels. Iris angiography showed no leakage of dye. Managed by observation over a mean follow-up of 37.7 months (range, 3–129), 96.4% eyes were stable and one (3.6%) regressed. No corectopia, ectropion uveae, hyphema, or metachronous anterior segment benign or malignant tumors occurred.

Conclusion:

Iris varix is primarily located in the inferotemporal quadrant and not associated with dysmorphic pupillary findings, progression, secondary glaucoma, or malignancy. Iris varices were benign vasculopathies with no associated ocular or vision-related morbidity.

[Drug-Based Therapy of Varicose Veins from the Perspective of Experimental Models]

Drug-Based Therapy of Varicose Veins from the Perspective of Experimental Models Abstract. Varicose remodeling of the venous wall primarily occurs in the lower extremities and is often associated with venous insufficiency. Although a large part of the western population shows various degrees of varicosis, little is known about the mechanisms driving their formation. In recent years, experimental animal models have spurred the identificatoin of target molecules and cellular mechanisms that control varicose remodeling processes. Thus, the chronic increase in venous wall tension appears to be a crucial determinant to stimulate signal cascades, culminating in increased proteolytic and proliferative activity of venous wall cells. The pharmacological inhibition of key molecules in these processes may provide a way to influence the course and severity of varicosis. This review article gives a brief insight into this topic.

Chronic Venous Disorders: The Dangerous, the Good, and the Diverse

Chronic venous disorders are common vascular pathology of great medical and socioeconomic impact, characterized by a wide spectrum of clinical manifestations occurring with symptoms and/or signs that vary in type and severity. The predominant pathophysiological mechanisms of chronic venous disease start from the development of venous hypertension from shear stress and reflux, leading to endothelial dysfunction and venous wall dilatation. The altered hemodynamic transduces physical signals into harmful bio-molecular pathways, creating a vicious cycle among shear stress, proteolytic remodeling, and inflammatory processes. This intricate network is further exacerbated by the degradation of protective endothelial glycocalyx. In this special issue, at least three main aspects of these interactions are highlighted: the dangerous, the good, and the diverse, which may help to focus attention on the biomolecular mechanisms and the possible targeted therapy of chronic venous disorders (CVeD).

Glycyrrhetinic Acid Antagonizes Pressure-Induced Venous Remodeling in Mice

Development of spider veins is caused by the remodeling of veins located in the upper dermis and promoted by risk factors such as obesity or pregnancy that chronically increase venous pressure. We have repeatedly shown that the pressure-induced increase in biomechanical wall stress is sufficient to evoke the formation of enlarged corkscrew-like superficial veins in mice. Subsequent experimental approaches revealed that interference with endothelial- and/or smooth muscle cell (SMC) activation counteracts this remodeling process. Here, we investigate whether the herbal agent glycyrrhetinic acid (GA) is a suitable candidate for that purpose given its anti-proliferative as well as anti-oxidative properties. While basic abilities of cultured venous SMCs such as migration and proliferation were not influenced by GA, it inhibited proliferation but not angiogenic sprouting of human venous endothelial cells (ECs). Further analyses of biomechanically stimulated ECs revealed that GA inhibits the DNA binding capacity of the mechanosensitive transcription factor activator protein-1 (AP-1) which, however, had only a minor impact on the endothelial transcriptome. Nevertheless, by decreasing gelatinase activity in ECs or mouse veins exposed to biomechanical stress, GA diminished a crucial cellular response in the context of venous remodeling. In line with the observed inhibitory effects, local transdermal application of GA attenuated pressure-mediated enlargement of veins in the mouse auricle. In summary, our data identifies GA as an inhibitor of EC proliferation, gelatinase activity and venous remodeling. It may thus have the capacity to attenuate spider vein formation and remodeling in humans.

Magnolol inhibits venous remodeling in mice

Due to gravity the venous vasculature in the lower extremities is exposed to elevated pressure levels which may be amplified by obesity or pregnancy. As a consequence, venules dilate and may be slowly transformed into varicose or spider veins. In fact, chronically elevated venous pressure was sufficient to cause the corkscrew-like enlargement of superficial veins in mice. We hypothesized that biomechanical activation of endothelial cells contributes to this process and investigated the inhibitory capacity of Magnolol in this context - a natural compound that features multiple properties counteracting cellular stress. While Magnolol did not influence endothelial capillary sprout formation, it interfered with proliferation, ERK1/2 activity, gelatinase activity as well as baseline production of reactive oxygen species in these cells or murine veins. The anti-oxidative and anti-proliferative capacity of Magnolol was mediated through stimulation of heme oxygenase-1 expression. Finally, local transdermal application of Magnolol attenuated pressure-mediated development of varicose/spider veins in mice and was accompanied by the absence of proliferating and MMP-2 positive endothelial cells. Collectively, our data identified Magnolol as a potent inhibitor of biomechanically evoked endothelial cell activity during pressure-mediated venous remodeling processes which contribute to the development of varicose and spider veins.

Mechanotransduction in Blood and Lymphatic Vascular Development and Disease

The blood and lymphatic vasculatures are hierarchical networks of vessels, which constantly transport fluids and, therefore, are exposed to a variety of mechanical forces. Considering the role of mechanotransduction is key for fully understanding how these vascular systems develop, function, and how vascular pathologies evolve. During embryonic development, for example, initiation of blood flow is essential for early vascular remodeling, and increased interstitial fluid pressure as well as initiation of lymph flow is needed for proper development and maturation of the lymphatic vasculature. In this review, we introduce specific mechanical forces that affect both the blood and lymphatic vasculatures, including longitudinal and circumferential stretch, as well as shear stress. In addition, we provide an overview of the role of mechanotransduction during atherosclerosis and secondary lymphedema, which both trigger tissue fibrosis.

Genome-wide association analysis for chronic venous disease identifies EFEMP1 and KCNH8 as susceptibility loci

Chronic venous disease (CVD) is a multifactorial condition representing one of the most common disorders among populations of Western countries. The heritability of about 17% suggests genetic risk factors in CVD etiology. However, so far the genetic causes are unknown. We undertook the hitherto first genome-wide association study (GWAS) for CVD, analyzing more than 1.93 M SNPs in 4,942 German individuals, followed by replication in two independent German data sets. The combined analysis of discovery and replication stages (2,269 cases and 7,765 controls) yielded robust associations within the two genes EFEMP1 and KCNH8 (rs17278665, rs727139 with P < 5 × 10⁻⁸), and suggestive association within gene SKAP2 (rs2030136 with P < 5 × 10⁻⁷). Association signals of rs17278665 and rs727139 reside in regions of low linkage disequilibrium containing no other genes. Data from the ENCODE and Roadmap Epigenomics projects show that tissue specific marks overlap with the variants. SNPs rs17278665 and rs2030136 are known eQTLs. Our study demonstrates that GWAS are a valuable tool to study the genetic component of CVD. With our approach, we identified two novel genome-wide significant susceptibility loci for this common disease. Particularly, the extracellular matrix glycoprotein EFEMP1 is promising for future functional studies due to its antagonistic role in vessel development and angiogenesis.

Clinical features of venous insufficiency and the risk of venous thrombosis in older people

Venous thrombosis is common in older age, with an incidence of 0·5-1% per year in those aged >70 years. Stasis of blood flow is an important contributor to the development of thrombosis and may be due to venous insufficiency in the legs. The risk of thrombosis associated with clinical features of venous insufficiency, i.e., varicose veins, leg ulcers and leg oedema, obtained with a standardized interview was assessed in the Age and Thrombosis Acquired and Genetic risk factors in the Elderly (AT-AGE) study. The AT-AGE study is a case-control study in individuals aged 70 years and older (401 cases with a first-time venous thrombosis and 431 control subjects). We calculated odds ratios (ORs) and corresponding 95% confidence intervals (CI) adjusted for age, sex and study centre. Varicose veins and leg ulcer were associated with a 1·6-fold (95% CI 1·2-2·3) and 3·3-fold increased risk of thrombosis (95% CI 1·6-6·7), respectively, while the risk was increased 3·0-fold (95% CI 2·1-4·5) in the presence of leg oedema. The risk of thrombosis was highest when all three risk factors occurred simultaneously (OR: 10·5; 95% CI 1·3-86·1). In conclusion, clinical features of venous insufficiency, i.e., varicose veins, leg ulcers and leg oedema, are risk factors for venous thrombosis in older people.

Characterization of regional deformation and material properties of the intact explanted vein by microCT and computational analysis

PURPOSE

Detailed mechanical information of the vein is important to better understand remodeling of the vessel in disease states, but has been difficult to obtain due to its thinness, unique geometry, and limitations of mechanical testing. This study presents a novel method for characterizing deformation of the intact explanted vein under physiological loads and determining its material properties by combining high-resolution imaging and computational analysis.

METHODS

High-resolution CT (microCT) was used to image an iodine-stained, excised porcine internal jugular vein sample under extension to 100% and 120% of in situ length, and inflation and 2, 10, 20 mmHg of pressure, inside a microCT-compatible hydrostatic loading chamber. Regional strains were measured with the finite element (FE) image registration method known as Hyperelastic Warping. Material properties were approximated with inverse FE characterization by optimizing stiffness-related coefficients so to match simulated strains to the experimental measurements.

RESULTS

The observed morphology and regional strain of the vein were found to be relatively heterogeneous. The regional variability in the measured strain was primarily driven by geometry. Although iodine treatment may result in tissue stiffening, which requires additional investigation, it is effective in allowing detailed detection of vein geometry.

CONCLUSIONS

The feasibility and utility of using microCT and computational analysis to characterize mechanical responses and material properties of the vein were demonstrated. The presented method is a promising alternative or addition to mechanical testing for characterizing veins or other similarly delicate vessels in their native anatomical configuration under a wide range of realistic or simulated environmental and loading conditions.

Bortezomib protects from varicose-like venous remodeling

Despite the high prevalence of venous diseases that are associated with and based on the structural reorganization of the venous vessel wall, not much is known about their mechanistic causes. In this context, we demonstrated that the quantity of myocardin, a transcriptional regulator of the contractile and quiescent smooth muscle cell phenotype, was diminished in proliferating synthetic venous smooth muscle cells (VSMCs) of human and mouse varicose veins by 51 and 60%, respectively. On the basis of the relevance of proteasomal activity for such phenotypic changes, we hypothesized that the observed VSMC activation is attenuated by the proteasome inhibitor bortezomib. This drug fully abolished VSMC proliferation and loss of myocardin in perfused mouse veins and blocked VSMC invasion in collagen gels by almost 80%. In line with this, topical transdermal treatment with bortezomib diminished VSMC proliferation by 80%, rescued 90% of VSMC myocardin abundance, and inhibited varicose-like venous remodeling by 67 to 72% in a mouse model. Collectively, our data indicate that the proteasome plays a pivotal role in VSMC phenotype changes during venous remodeling processes. Its inhibition protects from varicose-like vein remodeling in mice and may thus serve as a putative therapeutic strategy to treat human varicose veins.