Increased Vein Wall Apoptosis in Varicose Vein Disease is Related to Venous Hypertension

Glycocalyx disruption, endothelial dysfunction and vascular remodeling as underlying mechanisms and treatment targets of chronic venous disease

The glycocalyx is an essential structural and functional component of endothelial cells. Extensive hemodynamic changes cause endothelial glycocalyx disruption and vascular dysfunction, leading to multiple arterial and venous disorders. Chronic venous disease (CVD) is a common disorder of the lower extremities with major health and socio-economic implications, but complex pathophysiology. Genetic aberrations accentuated by environmental factors, behavioral tendencies, and hormonal disturbances promote venous reflux, valve incompetence, and venous blood stasis. Increased venous hydrostatic pressure and changes in shear-stress cause glycocalyx injury, endothelial dysfunction, secretion of adhesion molecules, leukocyte recruitment/activation, and release of cytokines, chemokines, and hypoxia-inducible factor, causing smooth muscle cell switch from contractile to synthetic proliferative phenotype, imbalance in matrix metalloproteinases (MMPs), degradation of collagen and elastin, and venous tissue remodeling, leading to venous dilation and varicose veins. In the advanced stages of CVD, leukocyte infiltration of the vein wall causes progressive inflammation, fibrosis, disruption of junctional proteins, accumulation of tissue metabolites and reactive oxygen and nitrogen species, and iron deposition, leading to skin changes and venous leg ulcer (VLU). CVD management includes compression stockings, venotonics, and surgical intervention. In addition to its antithrombotic and fibrinolytic properties, literature suggests sulodexide benefits in reducing inflammation, promoting VLU healing, improving endothelial function, exhibiting venotonic properties, and inhibiting MMP-9. Understanding the role of glycocalyx, endothelial dysfunction, and vascular remodeling should help delineate the underlying mechanisms and develop improved biomarkers and targeted therapy for CVD and VLU.

Discovering Potential Compounds for Venous Disease Treatment through Virtual Screening and Network Pharmacology Approach

Peripheral venous hypertension has emerged as a prominent characteristic of venous disease (VD). This disease causes lower limb edema due to impaired blood transport in the veins. The phlebotonic drugs in use showed moderate evidence for reducing edema slightly in the lower legs and little or no difference in the quality of life. To enhance the probability of favorable experimental results, a virtual screening procedure was employed to identify molecules with potential therapeutic activity in VD. Compounds obtained from multiple databases, namely AC Discovery, NuBBE, BIOFACQUIM, and InflamNat, were compared with reference compounds. The examination of structural similarity, targets, and signaling pathways in venous diseases allows for the identification of compounds with potential usefulness in VD. The computational tools employed were rcdk and chemminer from R-Studio and Cytoscape. An extended fingerprint analysis allowed us to obtain 1846 from 41,655 compounds compiled. Only 229 compounds showed pharmacological targets in the PubChem server, of which 84 molecules interacted with the VD network. Because of their descriptors and multi-target capacity, only 18 molecules of 84 were identified as potential candidates for experimental evaluation. We opted to evaluate the berberine compound because of its affordability, and extensive literature support. The experiment showed the proposed activity in an acute venous hypertension model.

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.

Augmentation of miR-202 in varicose veins modulates phenotypic transition of vascular smooth muscle cells by targeting proliferator-activated receptor-γ coactivator-1α

In varicose veins, vascular smooth muscle cells (VSMCs) often show abnormal proliferative and migratory rates and phenotypic transition. This study aimed to investigate whether microRNA (miR)-202 and its potential target, peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), were involved in VSMC phenotypic transition. miR-202 expression was analyzed in varicose veins and in VSMCs conditioned with platelet-derived growth factor. The effect of miR-202 on cell proliferation and migration was assessed. Furthermore, contractile marker SM-22α, synthetic markers vimentin and collagen I, and PGC-1α were analyzed by Western blot analysis. The modulation of PGC-1α expression by miR-202 was also evaluated. In varicose veins and proliferative VSMCs, miR-202 expression was upregulated, with decreased SM-22α expression and increased vimentin and collagen I expression. Transfection with a miR-202 mimic induced VSMC proliferation and migration, whereas a miR-202 inhibitor reduced cell proliferation and migration. miR-202 mimic constrained luciferase activity in HEK293 cells that were cotransfected with the PGC-1α 3'-untranslated region (3'-UTR) but not those with mutated 3'-UTR. miR-202 suppressed PGC-1α protein expression, with no influence on its messenger RNA expression. PGC-1α mediated VSMC phenotypic transition and was correlated with reactive oxygen species production. In conclusion, miR-202 affects VSMC phenotypic transition by targeting PGC-1α expression, providing a novel target for varicose vein therapy.

Assessment of apoptosis in the native vein used for hemodialysis access

Aim

To determine whether apoptosis is more common in previously punctured native veins than in non-punctured native veins among patients who undergo surgical creation of arteriovenous fistula (AVF) for dialysis access.

Methods

Cephalic vein specimens were obtained from January 1, 2013 to December 31, 2014 from 60 patients, 30 with previously punctured native veins and 30 with non-punctured native veins. Before AVF placement, a 1-cm vein segment was excised from distal part of the vein for histological, histochemical, and immunohistochemical analysis. Vein specimens were divided into two portions along the longitudinal axis and stained with hematoxylin and eosin for routine histological evaluation. Immunohistochemical analysis was used to localize Bax, p53, caspase 3, and Bcl-2 expression.

Results

The group with previously punctured veins showed significantly increased caspase 3 (P < 0.001, two-sided Fisher`s Exact Test) and Bax expression (P = 0.002, two-sided Fisher`s Exact Test) and significantly decreased Bcl-2 expression (P < 0.001, two-sided Fisher`s Exact Test) compared with the control group. There were no significant differences between the groups in p53 expression (χ² = 0.071, df = 1, P = 0.791). Fistula failure was significantly more common in the study group (26.7% vs 6.7%, χ² = 4.32, df = 1, P = 0.038).

Conclusion

Our study indicates a possible role of venipuncture in apoptosis development and a possible role of apoptosis in fistula failure, but we do not have sufficient evidence to conclude that it represents its main cause.

Dysregulated apoptosis of the venous wall in chronic venous disease and portal hypertension

Introduction

The etiology of varicose veins remains elusive. We hypothesized that abnormal cell cycle events in the vein wall may contribute to changes in the structural integrity, thus predisposing to the development of varicosities. The present study was designed to determine whether or not the same molecular apoptotic pathway exists between great saphenous and splenic veins.

Methods

Thirty-six samples of diseased splenic veins and varicose great saphenous veins were collected. Twenty-five samples of control splenic and great saphenous veins were also collected. The apoptotic cell proteins expression was immunohistochemically stained with antibodies (anti-Bax and anti-Bcl-xl). Apoptosis was evaluated by the terminal deoxynucleotidyl transferase-mediated nick-end labeling (TUNEL) assay and immunofluorescence staining. The morphology of apoptotic cells was observed with an electron microscope.

Results

The apoptotic ratio in walls (intima and media) of diseased splenic vein and varicose great saphenous vein groups were significantly lower than the corresponding regions in the splenic vein and great saphenous vein groups ( p < 0.01), respectively. A significant difference was not noted in the ratio change of apoptotic cells between the diseased splenic vein and varicose great saphenous vein groups ( p > 0.05). The high positive expression of Bcl-xl proteins was detected in the diseased splenic vein and varicose great saphenous vein groups, respectively. While the high positive expression of Bax proteins was also observed in the splenic vein and great saphenous vein groups, respectively. Electron microscopic observations confirmed that endothelial and smooth muscle cells in diseased splenic vein, varicose great saphenous vein, splenic vein, and great saphenous vein walls exhibited apoptotic morphologic features, such as fuzzy mitochondrial cristae, medullary changes, and margination of the nuclear chromatin.

Conclusions

Our results showed the same dysregulation of apoptosis via the intrinsic pathway in diseased splenic veins and varicose great saphenous veins. This observational study suggests that apoptotic down-regulation in the veins wall is a cause of diseased splenic veins and varicose great saphenous veins, but does not exclude the possibility that other mechanisms are involved.

Changes in levels of apoptosis in the walls of different segments of great saphenous varicose veins

Objective

Disordered programmed cell death may play a role in the development of superficial venous incompetence. We have determined the number of cells undergoing apoptosis and the alterations in the apoptotic level in the wall of different segments of the great saphenous varicose vein.

Methods

Twenty-one varicose great saphenous veins (VGSVs) (varicose group) and 12 normal great saphenous veins (GSVs) (control group) were collected, and the apoptosis level in the upper, middle, and lower segments were immunohistochemically stained with antibodies (anti-Bax and anti-Bcl-xl). Apoptosis was evaluated by the TUNEL assay and immunofluorescence staining. The morphology of apoptotic cells was observed with an electron microscope.

Results

Quantitative analysis showed that the apoptotic ratios in venous walls (intima and media) of the varicose group were significantly lower than the corresponding regions in the control group (all P < 0.05). A significantly higher apoptotic rates of the venous walls was observed in control group within the upper compared with the lower segment ( P < 0.05). Significantly higher positive proteins expression rates of Bcl-xl/Bax were also detected in the VGSVs compared with the GSVs within the three segments, respectively ( P < 0.01). Electron microscopic observations confirmed that endothelial and smooth muscle cells in varicose and normal vein walls exhibited apoptotic morphologic features, such as fuzzy mitochondrial cristae, medullary changes, and margination of the nuclear chromatin.

Conclusion

VGSV walls were found to have a significant decrease in apoptotic rate compared with that of GSVs. The rate of apoptosis in the intima and media within the upper segment was increased more than the middle and lower segments in the GSVs. Our findings confirm that programmed cell death is down-regulated in primary varicose veins.

Assessment of apoptotic cells in the wall of thrombophlebitic saphenous vein

Introduction

Programmed cell death plays a critical role in various physiological processes. In the present study, we investigated its possible pathogenic role in primary varicose veins. We studied histological changes in surgical specimens from thrombophlebitic saphenous veins. In thrombophlebitic saphenous, varicose, and healthy veins, we also determined the number of apoptotic cells, and investigated apoptosis in the role of the pathogenesis of varicose veins.

Methods

Forty-four specimens of thrombophlebitic saphenous veins and simple varicose veins were collected. Thirteen samples of normal great saphenous veins were also collected (control group). Apoptosis of venous walls was determined by terminal deoxynucleotidyl transferase-mediated nick-end labeling (TUNEL) and immunofluorescence methods. The corpuscular number per high-power field was counted under light microscopy.

Results

A significantly higher apoptotic ratio of the intima and media were observed in control veins as compared with thrombophlebitic saphenous veins and simple varicose veins ( p < 0.01). A significant difference was not observed between thrombophlebitic saphenous veins and simple varicose veins ( p > 0.05). A significant difference was not seen between the intima and media of the three groups ( p > 0.05).

Conclusion

In the walls of thrombophlebitic saphenous veins and varicose veins, the apoptotic indices were clearly decreased. The results suggest that the process of programmed cell death was inhibited in walls of thrombophlebitic saphenous veins and varicose veins.

Biomolecular mechanisms in varicose veins development

Varicose veins (VVs) can be described as tortuous and dilated palpable veins, which are more than 3 mm in diameter. They are one of the clinical presentations of chronic venous disorders, which are a significant cause of morbidity. The prevalence of VVs has been estimated at 25-33% in women and 10-20% in men and is still increasing at an alarming rate. Family history, older age, female, pregnancy, obesity, standing occupations, and a history of deep venous thrombosis are the predominant risk factors. A great amount of factors are implicated in the pathogenesis of VVs, including changes in hydrostatic pressure, valvular incompetence, deep venous obstruction, ineffective function of calf muscle pump, biochemical and structural alterations of the vessel wall, extracellular matrix abnormalities, impaired balance between growth factors or cytokines, genetic alterations, and several other mechanisms. Nevertheless, the issue of pathogenesis in VVs is still not completely known, even if a great progress has been made in understanding their molecular basis. This kind of studies appears promising and should be encouraged, and perhaps the new insight in this matter may result in targeted therapy or possibly prevention.