The Morphofunctional Changes in the Wall of Varicose Veins

Vicious Circle With Venous Hypertension, Irregular Flow, Pathological Venous Wall Remodeling, and Valve Destruction in Chronic Venous Disease: A Review

Substantial advances occurred in phlebological practice in the last two decades. With the use of modern diagnostic equipment, the patients' venous hemodynamics can be examined in detail in everyday practice. Application of venous segments for arterial bypasses motivated studies on the effect of hemodynamic load on the venous wall. New animal models have been developed to study hemodynamic effects on the venous system. In vivo and in vitro studies revealed cellular phase transitions of venous endothelial, smooth muscle, and fibroblastic cells and changes in connective tissue composition, under hemodynamic load and at different locations of the chronically diseased venous system. This review is an attempt to integrate our knowledge from epidemiology, paleoanthropology and anthropology, clinical and experimental hemodynamic studies, histology, cell physiology, cell pathology, and molecular biology on the complex pathomechanism of this frequent disease. Our conclusion is that the disease is initiated by limited genetic adaptation of mankind not to bipedalism but to bipedalism in the unmoving standing or sitting position. In the course of the disease several pathologic vicious circles emerge, sustained venous hypertension inducing cellular phase transitions, chronic wall inflammation, apoptosis of cells, pathologic dilation, and valvular damage which, in turn, further aggravate the venous hypertension.

Morphological study of incompetent saphenous veins: apoptosis and ultrastructural changes of smooth muscle cells

BACKGROUND

Varicose veins affect approximately 25% of people in industrialized countries.

METHODS

The study aimed at detecting apoptotic cells and histopathological changes in varicose vein walls. Patients (N.=41) with varicose veins and 30 control group patients were divided into two groups according to their age (younger and older than 50 years). Apoptosis was determined by the TUNEL assay, elastin and collagen IV expression by immunohistochemistry and ultrastructural changes by transmission electron microscopy.

RESULTS

The results show that the number of apoptotic cells in the layers of varicose veins increased, in particular in a group of patients aged over 50 years. In the varicose veins as compared to control veins the elastic fibers were found to be thinner, more fragmented and disorderly arranged. Elastin and collagen IV expression was found to decline in the intima and the media of varicose veins in both age groups. Electron microscopy demonstrated hypertrophy and degeneration of smooth muscle cells. Furthermore, cells with ultrastructural feature of apoptosis were noted. In the disorganized and expanded extracellular matrix membrane-bound vesicles, ghost bodies with different size and electron density were observed. Ghost bodies seem to bud off from smooth muscle cells and are likely to be involved in extracellular matrix remodeling as they are seen in close contact with collagen fibers.

CONCLUSIONS

The study demonstrates increase of apoptotic cells in the wall of varicose veins along with vein wall structural abnormalities including alterations of smooth muscle cells and decline of elastin and collagen IV expression.

Pathophysiology and Genetic Associations of Varicose Veins: A Narrative Review

Varicose veins (VVs) have a high prevalence worldwide and have become a major medical burden. Their pathophysiology involves a complex interplay of inflammation and tissue remodeling, and current treatment is limited by its impact on the pathophysiological mechanisms. In addition, despite clear environmental factors, family history is an important risk factor, suggesting a genetic component to the risk of developing VVs. Our understanding of the pathogenesis of these diseases has benefited greatly from the expansion of population genetic studies, from pioneering family studies to large genome-wide association studies; we now find multiple risk loci for each venous disease. This review considers the pathophysiology of VVs, highlighting the current state of genetic knowledge. We also propose future directions for research.

Molecular Determinants of Chronic Venous Disease: A Comprehensive Review

Chronic Venous Disease (CVD) refers to several pathological and hemodynamic alterations of the veins of lower limbs causing a wide range of symptoms and signs with a high prevalence in the general population and with disabling consequences in the most severe forms. The etiology and pathophysiology of CVD is complex and multifactorial, involving genetic, proteomic, and cellular mechanisms that result in changes to the venous structure and functions. Expressions of several genes associated with angiogenesis, vascular development, and the regulation of veins are responsible for the susceptibility to CVD. Current evidence shows that several extracellular matrix alterations (ECM) could be identified and in some cases pharmacologically targeted. This review shows the most up to date information on molecular determinants of CVD in order to provide a complete overview of the current knowledge on this topic. In particular, the article explores the genetic influence, the hormonal influence, ECM imbalance, and histopathology of CVD and the role of endothelial dysfunction in CVD.

Clinical and Pathological Correlations in Chronic Venous Disease

BACKGROUND

Chronic Venous Disease (CVD) has a high prevalence in the western world. Varicose veins (VVs) are the main signs of this disease that is characterized by important pathological vessel wall changes. The aim of this study is to correlate the main histopathological abnormalities with related clinical issues of CVD.

METHODS

A cohort of patients with VVs scheduled for open surgical treatment namely stab avulsion of VVs was recruited. Subsequently, venous tissue from stab avulsion was collected in order to evaluate the following biomarkers: Vascular-Endothelial Growth Factor (VEGF), Protein Gene Product 9.5 (PGP 9.5), Fibronectin (FN), and Matrix Metalloproteinase-9 (MMP-9). The Clinical-Etiology-Anatomy-Pathophysiology (CEAP) criteria were used to classify CVD.

RESULTS

Fourteen tissue fragments were processed for histological and immunohistochemical studies. Of these, 43% were from CEAP C2 patients, 36% from CEAP C3 patients, and 21% from CEAP C4 patients. CEAP Class C2 had few to moderate structures positive to VEGF; occasional structures positive to Fibronectin, numerous structures positive to MMP9, few to moderate structures positive to PGP 9.5. CEAP Class C3 had moderate structures positive to VEGF; few to moderate structures positive to Fibronectin; many structures positive to MMP9; few to moderate structures positive to PGP 9.5. CEAP Class C4 had numerous structures positive to VEGF; numerous structures positive to Fibronectin; abundant structures positive to MMP-9; few structures positive to PGP 9.5.

CONCLUSIONS

In this study, positive VEGF, FN, and MMP-9 structures were found with increasing trends in relation to the disease staging. VEGF and FN are associated with a progressive increase from C2 to C4. The MMP-9 marker has an important positivity even at early stage of the disease, being higher in CEAP C4 patients. PGP 9.5 decreases in CEAP C4 patients and this is concordant to decreased vein wall innervation.

Cellular senescence at the saphenofemoral junction in patients with healthy, primary varicose and recurrent varicose veins - A pilot study

OBJECTIVES

Cellular senescence could play a role in the development of venous disease. Superficial venous reflux at the saphenofemoral junction is a common finding in patients with primary varicose veins. Furthermore, reflux in this essential area is associated with higher clinical stages of the disease and recurrent varicose veins. Therefore, this pilot study aimed to investigate cellular senescence in the immediate area of the saphenofemoral junction in patients with healthy veins, primary varicose veins and additionally in patients with recurrent varicose veins due to a left venous stump.

METHODS

We analyzed vein specimens of the great saphenous vein immediately at the saphenofemoral junction. Healthy veins were collected from patients who underwent arterial bypass reconstructions. Samples with superficial venous reflux derived from patients who received high ligation and stripping or redo-surgery at the groin, respectively. Sections were stained for p53, p21, and p16 as markers for cellular senescence and Ki67 as a proliferation marker.

RESULTS

A total of 30 samples were examined (10 healthy, 10 primary varicose, and 10 recurrent varicose veins). We detected 2.10% p53⁺ nuclei in the healthy vein group, 3.12% in the primary varicose vein group and 1.53% in the recurrent varicose vein group, respectively. These differences were statistically significant (p = 0.021). In the healthy vein group, we found 0.43% p16⁺ nuclei. In the primary varicose vein group, we found 0.34% p16⁺ nuclei, and in the recurrent varicose vein group, we found 0.74% p16⁺ nuclei. At the p < 0.05 level, the three groups tended to be significant without reaching statistical significance (p = 0.085). There was no difference in respect of p21 and Ki67.

CONCLUSION

We found significantly higher expression rates of p53 in primary varicose veins at the saphenofemoral junction than in healthy veins. p16 expression tended to be increased in the recurrent varicose vein group. These preliminary findings indicate that cellular senescence may have an impact in the development of varicose veins or recurrence. Further studies addressing this issue are necessary.

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.

Elevated c-fos expression is correlated with phenotypic switching of human vascular smooth muscle cells derived from lower limb venous varicosities

BACKGROUND

Lower limb venous varicosities (VVs) are clinically common; however, their molecular underpinnings are far from well elucidated. Previous studies have demonstrated that the phenotypic transition of vascular smooth muscle cells (VSMCs) plays a critical role in VV pathogenesis and that c-fos is upregulated in VSMCs from VVs. The present study investigated the histologic and cytologic changes in VVs and the correlation between c-fos upregulation and VSMC phenotypic switching.

METHODS

Thirty-four patients with VVs (VV group) and 13 patients undergoing coronary artery bypass using autologous great saphenous vein segments (normal vein [NV] group) were enrolled in the present study. The great saphenous veins of both groups were harvested for subsequent experiments. Hematoxylin and eosin staining was performed for vein morphologic analysis. Real-time quantitative polymerase chain reaction, immunohistochemistry, and Western blot assays were used to assess mRNA and protein expression of c-fos, α-smooth muscle actin (α-SMA), and osteopontin (OPN). Simple linear regression was used to evaluate the correlation between c-fos and OPN/α-SMA. Primary VSMCs were isolated from both groups and cultured in vitro. A cell counting kit-8 assay and scratch-wound assay were used to analyze the proliferation and migration abilities of the cells, respectively.

RESULTS

The mean age of the patients in the NV and VV groups was 61.4 ± 3.8 years and 59.5 ± 10.4 years, respectively. The vein cavities of the VV group were dilated, and the arrangement of the cells was disordered. The tunica media of the VV group was thicker than that of the NV group owing to the accumulation and proliferation of VSMCs. Significantly elevated mRNA levels of c-fos and OPN were observed in the VV group compared with the NV group, and a positive correlation was further demonstrated between the mRNA levels of c-fos and OPN/α-SMA (R², 0.5524; P < .001). The VSMCs derived from the VV group were more numerous (as shown by the cell counting kit-8 assay) and had a significantly greater migration speed (as shown by the scratch-wound assay) than those derived from the NV group. Moreover, the protein expression of c-fos was significantly upregulated in VSMCs derived from the VV group, and this change was accompanied by a decrease in α-SMA and an increase in OPN expression.

CONCLUSIONS

Both mRNA and protein expression of c-fos were upregulated in VV specimens, and the phenotypic biomarkers (OPN/α-SMA) were altered concurrently. VSMCs derived from VVs showed increased proliferation and migration abilities. Upregulation of c-fos might play a role in the phenotypic switching of VSMCs and subsequently participate in the pathogenesis of VVs.

CLINICAL RELEVANCE

C-fos is an immediate early gene owing to the transient and rapid change in its expression in response to stimuli. It is involved in the regulation of cell proliferation, cell growth, and cell movement. In the present study, varicose vein specimens showed increased mRNA and protein expression of c-fos, accompanied by altered phenotypic biomarkers. The upregulation of the c-fos gene in smooth muscle cells cultured from varicose vein specimens might be associated with phenotypic switching and functional disturbance. These results could contribute to the exploration of the molecular mechanisms underlying the pathogenesis of varicose veins and the development of new therapeutic strategies.

Phlebosclerosis in lower extremities veins - a systematic review

Phlebosclerosis is a venous wall degenerative disease which has gained little popularity in the literature due to its uncertain clinical significance. The objective of this review is to evaluate the epidemiology, etiology and clinical significance of phlebosclerosis in lower extremities veins, particularly the effect of preexisting phlebosclerosis of the great saphenous vein on vein graft patency. Medline was searched from inception until November 1, 2019. Reference lists of included studies were scanned. Only articles published after 1949 were included. Two reviewers independently screened titles/abstracts and full-text papers for any study design in relation to phlebosclerosis in lower extremities veins and abstracted data. A total of 16 Cohort studies and one case-control study (3708 participants, mean age 61.8 years, 59.3 % men, and 40.7 % women) were included after screening 317 titles and abstracts, and 80 full-text articles. The incidence of phlebosclerosis ranged from 1.5-9.7 % depending on the radiological features. On the contrary, the incidence of the phlebosclerotic great saphenous vein prior to its use as a vein graft was 26.9-91 % on histological examination. The small saphenous vein was the most common location of phlebosclerosis followed by the great saphenous vein. There is a link between phlebosclerosis and age, venous insufficiency and haemodialysis. As for the vein graft patency seven studies demonstrated a correlation between preexisting phlebosclerosis and vein graft stenosis, whereas three studies failed to prove any association. In conclusion, the radiological incidence of phlebosclerosis depended on the ultrasound findings. Its presence in the great saphenous vein prior to its use as a vein graft is established on histological examination. The small saphenous vein is mainly affected. Risk factors included age, haemodialysis, and venous insufficiency. Preexisting wall thickness of the great saphenous vein graft seemed to affect negatively its patency in bypass surgery.

[Venous wall weackness pathogenesis in varicose vein disease]

Varicose veins of lower extremities, varicocele and varicose dilation of pelvic veins including ovaricovaricocele are the most common non-inflammatory diseases of venous system. The same mechanisms determined varicose dilatation regardless localization of the vein. First of all, these are wall weakness and valvular insufficiency combined with hereditary collagen fiber defectiveness in case of undifferentiated connective tissue syndrome. Imbalance between different types of collagen in vascular wall (especially types I and III) also results wall weakness. Other important mechanisms are smooth muscle cells dysfunction followed by excessive intracellular synthesis and intramuscular fibrosis and imbalance of protease system due to overproduction of metalloproteinases. We consider that different forms of varicose veins (varicose veins of lower extremities, varicocele, ovaricovaricocele) may be unified within one pathology (varicose vein disease).

Peptide growth factors and their receptors in the vein wall

The varicose vein wall remodeling is a very complex process, which is controlled by numerous factors, including peptide growth factors. The aim of the study was to assess a/b FGF, IGF-1, TGF-β1, VEGF-A and their receptors in the vein wall. Varicose vein samples were taken from 24 patients undergoing varicose vein surgery. The control material consisted of vein specimens collected from 12 patients with chronic limb ischemia. Contents of aFGF, bFGF, IGF-I, TGF-β1, VEGF, IGF-1R, VEGF R1 and VEGF R2 were assessed with ELISA method. Protein expression of FGF R1 and TGF-β RII were evaluated with western blot. Increased contents of aFGF, IGF-1 and VEGF-A were found in varicose veins in comparison with normal ones (p<0.05). In contrast, a significant decrease in TGF-β content was demonstrated in varicose veins (p<0.05). Furthermore, there was no difference in bFGF content in both groups (p>0.05). IGF-1 R content was significantly increased in varicose veins (p<0.05). There was no difference in VEGF R1 content between varicose and normal veins (p>0.05), whereas VEGF R2 content was significantly increased in varicose veins (p<0.05). Western blot demonstrated increased expression of TGF-β RII in varicose veins (p<0.05) and similar expression of FGF R1 in both groups (p>0.05). Demonstrated changes in peptide growth factors and their receptors may disturb metabolism of extracellular matrix in the varicose vein wall and contribute to the development of the disease to its more advanced stages.

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.

Combined effect of chronic partial occlusion and orthostatic load on the saphenous vein network: A varicosity model in the rat

Objectives

We tested the combined effects of chronic flow obstacle and gravitation on the saphenous vein network of rats.

Methods

A narrowing clip (500 µm, partial occlusion) was administered on the saphenous vein main branch for 4, 8 and 12 weeks, either separately or in combination with chronic orthostatic load (tilted tube-cages for four weeks). Resulting network changes were studied on plastic casts, by video-microscopy, histochemistry–immunohistochemistry and image analysis.

Results

A rich collateral venous network developed containing newly formed masses of retrograde conducting small veins. Their walls had less dense elastica, less contractile protein, increased cell division activity and macrophage invasion, and were more sensitive to chronic gravitational load.

Conclusions

Hemodynamic disturbance induces remodeling of the saphenous vein network. Walls of veins being in the process of flow-induced morphological remodeling are weak and more sensitive to gravitational load. Reticular vein conglomerates, veins with local dilations, and convoluted courses were observed.

The venous perforators of the lower limb - A new terminology

Latin anatomical terminology of venous perforators (communications between superficial and deep venous systems of the lower limb) was adopted as late as 2001 as an appendix to the official nomenclature following the clinicians’ request. Terminologia Anatomica, last version of the Latin anatomical nomenclature, published in 1998, unfortunately contains no terms concerning these veins. During the 14th World Congress of the International Union of Phlebology, a consensus document was laid to expand the nomenclature of the lower limb veins, above all 36 new terms for perforators of the lower limb, both in Latin and English languages. This consensus document will be incorporated in the next version of the Terminologia Anatomica. But there are more constant and well-described ones, especially in the foot, and this article reviews in particular the current knowledge on the anatomy of the venous perforators of the whole lower limb.

Chemokines and Growth Factors Produced by Lymphocytes in the Incompetent Great Saphenous Vein

The role of cytokines in the pathogenesis of chronic venous disease (CVD) remains obscure. It has been postulated that oscillatory flow present in incompetent veins causes proinflammatory changes. Our earlier study confirmed this hypothesis. This study is aimed at assessing chemokines and growth factors (GFs) released by lymphocytes in patients with great saphenous vein (GSV) incompetence. In 34 patients exhibiting reflux in GSV, blood was derived from the cubital vein and from the incompetent saphenofemoral junction. In 12 healthy controls, blood was derived from the cubital vein. Lymphocyte culture with and without stimulation by phytohemagglutinin (PHA) was performed. Eotaxin, interleukin 8 (IL-8), macrophage inflammatory protein 1 A and 1B (MIP-1A and MIP-1B), interferon gamma-induced protein (IP-10), monocyte chemoattractant protein-1 (MCP-1), interleukin 5 (IL-5), fibroblast growth factor (FGF), granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), platelet-derived growth factor-BB (PDGF-BB), and vascular endothelial growth factor (VEGF) were assessed in culture supernatants by a Bio-Plex assay. Higher concentrations of eotaxin and G-CSF were revealed in the incompetent GSV, compared with the concentrations in the patients' upper limbs. The concentrations of MIP-1A and MIP-1B were higher in the CVD group while the concentration of VEGF was lower. In the stimulated cultures, the concentration of G-CSF proved higher in the incompetent GSV, as compared with the patients' upper limbs. Between the groups, the concentration of eotaxin was higher in the CVD group, while the IL-5 and MCP-1 concentrations were lower. IL-8, IP-10, FGF, GM-CSF, and PDGF-BB did not reveal any significant differences in concentrations between the samples. These observations suggest that the concentrations of chemokines and GFs are different in the blood of CVD patients. The oscillatory flow present in incompetent veins may play a role in these changes. However, the role of cytokines in CVD requires further study.