Varicose Remodeling of Veins Is Suppressed by 3-Hydroxy-3-Methylglutaryl Coenzyme A Reductase Inhibitors

Simvastatin inhibits hepatic stellate cells activation by regulating the ferroptosis signaling pathway

BACKGROUND & AIMS

Ferroptosis is a form of regulated cell death and its promotion in hepatic stellate cells (HSCs) attenuates liver fibrosis. Statins, which are 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, may induce ferroptosis via the downregulation of glutathione peroxidase 4 (GPX4) by inhibiting the mevalonate pathway. However, little evidence is available regarding the association between statins and ferroptosis. Therefore, we investigated the association between statins and ferroptosis in HSCs.

METHODS

Two human HSC cell lines, LX-2 and TWNT-1, were treated with simvastatin, an HMG-CoA reductase inhibitor. Mevalonic acid (MVA), farnesyl pyrophosphate (FPP), and geranylgeranyl pyrophosphate (GGPP) were used to determine the involvement of the mevalonate pathway. We performed a detailed analysis of the ferroptosis signaling pathway. We also investigated human liver tissue samples from patients with nonalcoholic steatohepatitis to clarify the effect of statins on GPX4 expression.

RESULTS

Simvastatin reduced cell mortality and inhibited HSCs activation, accompanied by iron accumulation, oxidative stress, lipid peroxidation, and reduced GPX4 protein expression. These results indicate that simvastatin inhibits HSCs activation by promoting ferroptosis. Furthermore, treatment with MVA, FPP, or GGPP attenuated simvastatin-induced ferroptosis. These results suggest that simvastatin promotes ferroptosis in HSCs by inhibiting the mevalonate pathway. In human liver tissue samples, statins downregulated the expression of GPX4 in HSCs without affecting hepatocytes.

CONCLUSIONS

Simvastatin inhibits the activation of HSCs by regulating the ferroptosis signaling pathway.

Design of an Herbal Preparation Composed by a Combination of Ruscus aculeatus L. and Vitis vinifera L. Extracts, Magnolol and Diosmetin to Address Chronic Venous Diseases through an Anti-Inflammatory Effect and AP-1 Modulation

Chronic venous disease (CVD) is an often underestimated inflammatory pathological condition that can have a serious impact on quality of life. Many therapies have been proposed to deal with CVD, but unfortunately the symptoms recur with increasing frequency and intensity as soon as treatments are stopped. Previous studies have shown that the common inflammatory transcription factor AP-1 (activator protein-1) and nuclear factor kappa-activated B-cell light chain enhancer (NF-kB) play key roles in the initiation and progression of this vascular dysfunction. The aim of this research was to develop a herbal product that acts simultaneously on different aspects of CVD-related inflammation. Based on the evidence that several natural components of plant origin are used to treat venous insufficiency and that magnolol has been suggested as a putative modulator of AP-1, two herbal preparations based on Ruscus aculeatus root extracts, and Vitis vinifera seed extracts, as well as diosmetin and magnolol, were established. A preliminary MTT-based evaluation of the possible cytotoxic effects of these preparations led to the selection of one of them, named DMRV-2, for further investigation. First, the anti-inflammatory efficacy of DMRV-2 was demonstrated by monitoring its ability to reduce cytokine secretion from endothelial cells subjected to LPS-induced inflammation. Furthermore, using a real-time PCR-based protocol, the effect of DMRV-2 on AP-1 expression and activity was also evaluated; the results obtained demonstrated that the incubation of the endothelial cells with this preparation almost completely nullified the effects exerted by the treatment with LPS on AP-1. Similar results were also obtained for NF-kB, whose activation was evaluated by monitoring its distribution between the cytosol and the nucleus of endothelial cells after the different treatments.

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.

Monocyte chemoattractant protein 1 plasma concentration in blood from varicose veins decreases under venoactive drug treatment

BACKGROUND

Vein-specific inflammation leads to vascular smooth muscle cells proliferation and extracellular matrix degradation of vein wall. This process is known as remodeling and is promoted by "trapped" leukocytes. Monocyte chemoattractant protein 1 (MCP-1) is a chemokine responsible for trafficking of leukocytes from blood to vein wall. The aim of this study was to measure the MCP-1 concentration in varicose veins blood before and after venoactive drug therapy and to compare it with a concentration of blood from varicose veins of subjects who did not receive drug treatment.

METHODS

Non-randomized comparative study was conducted on 30 patients with primary varicose veins. 20 patients of the study group received diosmin 900 mg/hesperidin 100 mg once daily. 10 controls received no treatment. MCP-1 level was measured (pg/mL) in the blood from varicose veins twice, at the day of inclusion and after 60 days. Legs discomfort related to chronic venous disease (CVD) symptoms was measured with 10-cm Visual Analogue Scale (VAS) at inclusion and at completion of the study.

RESULTS

Median (interquartile range, IQR) MCP-1 concentrations in treatment and control groups at inclusion were 171.9 (124.4-216.0) and 157.0 (120.1-163.1), resp., P=0.285. After 60 days of treatment MCP-1 level decreased, but non-significantly to 152.3 (124.1-178.3). In patients who did not receive treatment chemokine level slightly increased to 163.0 (134.0-172.9). Median changes over time were -6.6 (-30.9-7.4) and 10.6 (-3.7-19.2) in the study and control groups, resp. (P=0.048). After 60 days in 12 of 19 and 2 of 9 patients of treatments and control groups MCP-1 decreased (P=0.103). Odds ratio for MCP-1 decreasing was 9.5 (95% CI 1.1-81.5, P=0.043) for those who received venoactive drug. Mean (± standard deviation [SD]) legs discomfort significantly dropped in the study group from 5.7 (±2.5) to 1.9 (±2.2) (P=0.0003), while in controls no changes were registered: 3.4 (±1.3) and 3.5 (± 1.4), resp., P=0.28). Mean difference of VAS at baseline and at follow-up was -3.5 (±2.6) and 0.9 (±2.1), resp. (P<0.0001).

CONCLUSIONS

Plasma concentration of MCP-1 in varicose veins blood demonstrates a tendency to decrease under two months treatment with a venoactive drug. Future studies are needed to reveal a possible role of MCP-1 as a target considering its role in varicose veins pathogenesis.

Biomechanical stretch-induced CLOCK upregulation in venous smooth muscle cells promotes phenotypic and functional transformation

BACKGROUND

A chronic change in hemodynamic forces might activate the pathophysiological process of maladaptive venous remodeling. Biomechanical stretching stimulates venous smooth muscle cells (SMCs) in the media, and biomechanical loads exceeding physiological levels affect the intrinsic circadian rhythm and cellular phenotype. This study aimed to investigate the changes in the expression patterns of circadian clock genes under biomechanical stretching and their role in the regulation of the SMC phenotype.

METHODS

Circadian genes were detected in venous specimens and venous SMCs from patients with varicose veins (VVs) and patients with autologous vein grafts (normal veins). Molecular mechanism studies of SMC phenotypic switching under biomechanical stretching were performed in human umbilical venous SMCs (HUVSMCs).

RESULTS

CLOCK upregulation was observed in VVs. The circadian rhythm was disrupted in venous SMCs derived from VVs. In addition, CLOCK expression and cell proliferation and migration were increased in HUVSMCs exposed to biomechanical stretch. CLOCK overexpression activated NF-κB signaling and phenotypic transformation in HUVSMCs, whereas CLOCK depletion had inhibitory effects on these pathways. Further experiments revealed that the CLOCK protein regulates phenotypic and functional transformation via the RHOA/ROCK1 pathway.

CONCLUSIONS

Our results demonstrate that CLOCK is a crucial regulator of the SMC phenotype under mechanical stretch. The CLOCK/RHOA/ROCK1 pathway is important in phenotypic adaptation, and targeting RHOA/ROCK1 could potentially reverse stretch-induced phenotypic switching.

Verständnis, Prävention und Behandlung von venösen und lymphatischen Erkrankungen basieren auf der Arbeit von Grundlagenforschern

Zweck Die Rolle der Grundlagenforschung in allen Bereichen der Medizin war, ist und wird auch immer kritisch sein. Die Grundlagenforschung leistet einen Beitrag zu Wissen und Fortschritt. In der Phlebologie ist es nicht anders. Das Manuskript beschreibt die neuesten Errungenschaften der Grundlagenforschung zum Thema Phlebologie.

Methode Der vorliegende Beitrag beleuchtet Publikationen mit dem Thema Grundlagenforschung in der Phlebologie aufgrund einer PubMed-Suche. Die gefundenen Artikel sowie die verschiedenen Schritte, die für Grundlagenforschung angewendet werden, werden diskutiert. Die Relevanz dieser Arbeiten in Bezug auf die tägliche Arbeit in der Phlebologie wird beleuchtet, insbesondere in Bezug auf die Veränderungen der Venenklappen, der Venenwand und den darauffolgenden Störungen des Blutstroms.

Ergebnisse Veränderte Venenwände bei Varizen sind das Ergebnis eines Umbauprozesses aufgrund von Veränderungen der Venenwand auf Zellebene sowie im Interstitium. An diesem Prozess sind glatte Muskelzellen beteiligt. Ferner wurde eine Transformation vom kontraktilen zum sekretorischen Phänotyp beschrieben. In diesem Umbaustadium sind Matrix-Metalloproteinasen (MMP) aktiv beteiligt. Sie tragen zur beobachteten endgültigen Veränderung der Venenwand bei Varizen bei. Die Eigenschaften des Blutstroms und die Funktion der Venenklappen haben sich als zusammenhängendes System erwiesen.

Schlussfolgerungen Die wissenschaftliche Methode ist der Grundpfeiler der Grundlagenforschung. Varizen entstehen durch einen veränderten Blutstrom und einen Umbau der Venenwand.

The Inhibition of Prolyl Oligopeptidase as New Target to Counteract Chronic Venous Insufficiency: Findings in a Mouse Model

(1) Background: Chronic venous insufficiency (CVI) is a common disorder related to functional and morphological abnormalities of the venous system. Inflammatory processes and angiogenesis alterations greatly concur to the onset of varicose vein. KYP-2047 is a selective inhibitor of prolyl oligopeptidase (POP), a serine protease involved in the release of pro-angiogenic molecules. The aim of the present study is to evaluate the capacity of KYP-2047 to influence the angiogenic and inflammatory mechanisms involved in the pathophysiology of CVI. (2) Methods: An in vivo model of CVI-induced by saphene vein ligation (SVL) and a tissue block culture study were performed. Mice were subjected to SVL followed by KYP-2047 treatment (intraperitoneal, 10 mg/kg) for 7 days. Histological analysis, Masson's trichrome, Van Gieson staining, and mast cells evaluation were performed. Release of cytokines, nitric oxide synthase production, TGF-beta, VEGF, α-smooth muscle actin, PREP, Endoglin, and IL-8 quantification were investigated. (3) Results: KYP-2047 treatment ameliorated the histological abnormalities of the venous wall, reduced the collagen increase and modulated elastin content, lowered cytokines levels and prevented mast degranulation. Moreover, a decreased expression of TGF-beta, eNOS, VEGF, α-smooth muscle actin, IL-8, and PREP was observed in in vivo study; also a reduction in VEGF and Endoglin expression was confirmed in tissue block culture study. (4) Conclusions: For the first time, this research, highlighting the importance of POP as new target for vascular disorders, revealed the therapeutic potential of KYP-2047 as a helpful treatment for the management of CVI.

Therapeutic potential of flavonoids in the treatment of chronic venous insufficiency

Chronic venous insufficiency (CVI) is a common disorder associated with a variety of symptoms in later disease stages; despite the high prevalence of this pathology, suitable pharmaceutical therapies have not been explored to date. In this context, it was recently reported that a chronic increase in venous wall stress or biomechanical stretch is sufficient to cause development of varicose veins. Recent evidence demonstrate that flavonoids are natural substances that convey the circulatory system functionality, playing a key role in blood flow. Particularly, troxerutin, diosmin and horse chestnut extract, appear protective for the management of vascular diseases. The aim of the present study was to evaluate the effect of a flavonoid compound, containing troxerutin, diosmin and horse chestnut extract on in vitro model on HUVECs cells, due to its production of vasculoregulatory and vasculotropic molecules, on an ex-vivo model on mesenteric vessel contraction, to regularize mesenteric microcirculation and on in vivo model of CVI-induced by saphene vein ligation. Furthermore, the flavonoid compound capacity of extensibility and compatibility with peripheral veins was investigated through a tissue block culture study. The degree of absorption, the contractile venous activity, the histological analysis, the immunoistochemical and immunofluorescence evaluation for VEGF and CD34 were performed, together with inflammatory mediators dosage. For the first time, this research revealed the therapeutic potential of a compound, enriched with flavonoids, to be a supportive treatment, suitable to reduce varicose vein pathophysiology and to regularize venous tone.

Appropriate Surgical Treatment of Symptomatic Primary Varicose Veins Decreases Systemic Inflammatory Biomarkers

Objective: To evaluate the relationship between systemic inflammatory biomarkers and efficacy of surgical treatment of primary varicose veins of the lower extremities.

Methods: Total 12 patients who underwent endovenous laser ablation or stripping of varicose veins and six healthy subjects were enrolled. Structural and molecular changes of varices were assessed by immunohistochemical staining with anti-monocyte chemotactic protein-1 (MCP-1). MCP-1 and interleukin-6 (IL-6) levels in systemic antecubital blood were measured before and at 12 weeks after treatment.

Results: Immunohistochemical staining revealed prominent manifestation of MCP-1-positive endothelial cells in the walls of varices. Preoperative serum MCP-1 and IL-6 levels in the patients were significantly higher than those in the control (166±12 pg/mL vs 99±10 pg/mL, p=0.003; 5.1±0.95 pg/mL vs 0.0±0.0 pg/mL, p=0.001, respectively). The values were significantly correlated with the severity of chronic venous insufficiency (CVI). Postoperative serum MCP-1 level significantly decreased compared with the preoperative level (152±10 pg/mL vs 166±12 pg/mL, p=0.048). The values after endovenous laser ablation did not significantly decrease compared with those after stripping.

Conclusion: Varicose veins with CVI increase inflammatory biomarker levels in the local tissue and systemic blood. Appropriate treatment of symptomatic varicose veins decreases inflammatory biomarker levels.

[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.

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.

Brain Oxidative Stress During Experimental Sepsis Is Attenuated by Simvastatin Administration

During sepsis, brain damage is associated with oxidative stress due to overproduction of reactive oxygen species (ROS). Although there are recent reports about the benefits of statins in experimental sepsis and endotoxemia in peripheral organs, little is known about their effects in the CNS. Here, we investigated the antioxidant properties of simvastatin and its possible neuroprotective role during experimental sepsis. Male Wistar rats (250-300 g) were submitted to cecal ligation and puncture (CLP, n = 34) or remained as non-manipulated (naive, n = 34). Both groups were treated by gavage with simvastatin (20 mg/kg) or an equivalent volume of saline. The animals submitted to CLP were treated 4 days before and 48 h after surgery. One animal group was decapitated and the blood and brain were collected to quantify plasma levels of cytokines and assess astrogliosis and apoptosis in the prefrontal cortex and hippocampus. Another group was perfused with PBS (0.01 M), and the same brain structures were dissected to analyze oxidative damage. The CLP rats treated with simvastatin showed a reduction in nitric oxide (P < 0.05), IL1-β (P < 0.001), IL-6 (P < 0.01), and TBARS levels (P < 0.001) and an increase in catalase activity (P < 0.01), citrate synthase enzyme (P < 0.05), and normalized GSH/GSSG ratio. In addition, the histopathological analysis showed a reduction (P < 0.001) in reactive astrocytes and caspase 3-positive apoptotic cells. The results suggest a possible neuroprotective effect of simvastatin in structures responsible for spatial learning and memory and indicate the need for behavioral studies evaluating the impact on cognitive damage, as frequently seen in patients surviving sepsis.