Evaluation of aFGF/bFGF and FGF signaling pathway in the wall of varicose veins

Regulatory role of endogenous and exogenous fibroblast growth factor 1 in the cardiovascular system and related diseases

Fibroblast growth factor 1 (FGF1) has a critical regulatory role in the development of the cardiovascular system (CVS) and is strongly associated with the progression or treatment of cardiovascular diseases (CVDs). However, the regulatory mechanisms of FGF1 in CVS and CVDs have not yet been fully elucidated. Therefore, this review article summarized the existing literature reports on the role of FGF1 in CVS under physiological and pathological conditions. First, the expression and physiological functions of endogenous FGF1 is fully demonstrated. Then, we analyzed the role of exogenous FGF1 in normal CVS and related pathological processes. Specifically, the potential signaling pathways might be mediated by FGF1 in CVDs treatment is discussed in detail. In addition, the barriers and feasible solutions for the application of FGF1 are further analyzed. Finally, we highlight therapeutic considerations of FGF1 for CVDs in the future. Thus, this article may be as a reference to provide some ideas for the follow-up research.

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.

Molecular characteristics of varicocele: integration of whole-exome and transcriptome sequencing

OBJECTIVE

To explore the exome and transcriptome characteristics potentially underlying the pathogenesis of varicocele (VE).

DESIGN

Experimental study and cohort study.

SETTING

Academic research laboratory and university-affiliated hospital.

PATIENT(S)

Eleven VE patients whose fathers also had VE, plus 151 additional patients and 324 healthy men for variants genotyping; for the rat model, eight Sprague-Dawley male rats.

INTERVENTION(S)

Partial ligation of renal vein was conducted to establish VE rat models for whole-transcriptome RNA sequencing (RNA-seq).

MAIN OUTCOME MEASURE(S)

Genes with differential expression and/or harboring potential pathogenic variants detected via RNA-seq and whole-exome sequencing (WES) then subjected to population-based survey to define candidate genes of VE and analyzed via Gene Ontology and Kyoto Encyclopedia of Genes and Genomes to identify VE-involved pathways.

RESULT(S)

Whole-transcriptome RNA sequencing (RNA-seq) was performed using left spermatic veins of five rat VE models and three controls. We identified 9,688 genes and 18 pathways via RNA-seq, and via WES 160 genes harboring 279 potential deleterious variants and 16 pathways. Nine genes (AAMP, KMT2D, IRS2, SPINT1, IFT122, MKI67, DCHS1, LAMA2, and CBL) had variants in more than one patient who underwent WES, and six of these genes (AAMP, SPINT1, MKI67, IFT122, LAMA2, and DCHS1) showed differential expression. The population-based survey showed that AAMP, SPINT1, and MKI67 were strongly associated with VE risk. Together, two omic 67 data sets revealed four pathways potentially related to VE.

CONCLUSION(S)

For the first time, we have described the exome and transcriptome characteristics of VE. The bi-omics identified novel candidate genes and pathways involving the occurrence and development of VE.

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.

Divergent changes in the content and activity of MMP-26 and TIMP-4 in human umbilical cord tissues associated with preeclampsia

OBJECTIVES

Preeclampsia is the most common disorder associated with pregnancy. Our earlier findings revealed a substantial increase in the amount of matrix metalloproteinase-26 (matrilysin 2; MMP-26) in preeclamptic umbilical cord blood. The role of MMP-26 in preeclamptic umbilical cord tissue has not been fully elucidated. Some reports have indicated that the expression of matrilysin 2 and tissue inhibitor of matrix metalloproteinase 4 (TIMP-4) is coordinately regulated during progression of various diseases.

STUDY DESIGN

Therefore, we decided to assess the expression and activity of MMP-26 and TIMP-4 in normal and preeclamptic umbilical cord tissues - umbilical cord arteries (UCA), vein (UCV) and Wharton's jelly (WJ). Tissues obtained from 10 normal (control material) and 10 preeclamptic umbilical cords were assessed using immunoenzymatic assay, Western immunoblotting, reverse transcriptase - polymerase chain reaction and fluorometric determination of the enzyme activity.

RESULTS

All umbilical cord tissues, both control and preeclamptic, expressed MMP-26 and TIMP-4 in macromolecular complexes. Preeclampsia induced a significant increase in the content and actual activity of MMP-26 in UCV and WJ, as compared to control. The content of TIMP-4 in preeclamptic UCV and WJ was reduced. The content of MMP-26 mRNA was lower in UCA and UCV, whereas higher in WJ in preeclampsia.

CONCLUSIONS

Divergent changes in MMP-26 mRNA and protein expression suggest a difference in the factors controlling the matrilysin synthesis in healthy and preeclamptic subjects. The decrease in TIMP-4 content in preeclamptic UCV might be the main reason for significantly higher actual activity of MMP-26 in that tissue. Only in preeclamptic Wharton's jelly the changes were compatible in terms of the content and activity of MMP-26 and TIMP-4. It cannot be excluded that similar alterations can be observed for the whole vascular system of newborns delivered by mothers with preeclampsia.

Pathophysiological Mechanisms of Chronic Venous Disease and Implications for Venoactive Drug Therapy

Chronic venous disease (CVD) is a common pathology, with significant physical and psychological impacts for patients and high economic costs for national healthcare systems. Throughout the last decades, several risk factors for this condition have been identified, but only recently, have the roles of inflammation and endothelial dysfunction been properly assessed. Although still incompletely understood, current knowledge of the pathophysiological mechanisms of CVD reveals several potential targets and strategies for therapeutic intervention, some of which are addressable by currently available venoactive drugs. The roles of these drugs in the clinical improvement of venous tone and contractility, reduction of edema and inflammation, as well as in improved microcirculation and venous ulcer healing have been studied extensively, with favorable results reported in the literature. Here, we aim to review these pathophysiological mechanisms and their implications regarding currently available venoactive drug therapies.

High pressure–low flow remodeling of the rat saphenous vein wall

Objective

To better understand factors that may play a role in the development of varicosities.

Methods

We induced combined flow-pressure disturbance in the saphenous system of the rat by performing chronic partial clipping of the main branch. Biomechanical and quantitative histological testing was undertaken.

Results

A rich microvenous network developed. Bloodflow decreased to 0.65 ± 0.18 µl/s (control side, 3.5 ± 1.4 µl/s) and pressure elevated to 6.8 ± 0.7 mmHg (control side, 2.3 ± 0.2 mmHg, p < 0.05). Involution of the wall and lumen was observed (16.5%, 28.7% and 35.5% reduction in outer diameter, wall thickness and wall mass respectively, p < 0.05). Elevated macrophage (CD68) and cell division (Ki67) activity was observed. Elastic tissue and smooth muscle actin became less concentrated in the inner medial layers.

Conclusions

Low-flow induced morphological shrinking of the lumen in veins may override pressure-induced morphological distension. Loosening of the force-bearing elements during flow-induced wall remodeling may be an important pathological component in varicosity.

Evaluation of Vascular Endothelial Growth Factor and Its Receptors in Human Neointima

OBJECTIVE

The potential contribution of vascular endothelial growth factor (VEGF) in neointima development has been evaluated in numerous animal studies. However, its role remains controversial. Moreover, little is known about neointima formation in humans. In this study we assessed the expression of VEGF-A and its receptors in the human neointima formed within vascular anastomosis.

METHODS

The studied material comprised neointima samples harvested during secondary vascular operations from patients with chronic limb ischemia after aorto-/iliofemoral bypass grafting who developed vascular graft occlusion at 6-18 months after the initial surgical treatment. The control material consisted of segments of femoral arteries without visible macroscopic lesions collected from organ donors. The expression and content of VEGF-A, VEGFR-1 and VEGFR-2 were analyzed with PCR and ELISA methods, respectively.

RESULTS

We observed a significantly increased expression of VEGF-A and VEGFR-2 mRNA in neointima compared to the normal aorta. A significantly higher protein content of VEGF-A and VEGFR-2 in neointima samples compared to the controls was also observed. No significant difference of VEGFR-1 content and VEGFR-1 mRNA expression was found in the studied material.

CONCLUSION

These results indicate a possible involvement of the VEGF-A and VEGFR-2 system in the pathologic process of human neointima formation after vascular interventions.

Genetic polymorphisms of vein wall remodeling in chronic venous disease: a narrative and systematic review

Chronic venous disease encompasses a spectrum of disorders caused by an abnormal venous system. They include chronic venous insufficiency, varicose veins, lipodermatosclerosis, postthrombotic syndrome, and venous ulceration. Some evidence suggests a genetic predisposition to chronic venous disease from gene polymorphisms associated mainly with vein wall remodeling. The literature exploring these polymorphisms has not been reviewed and compiled thus far. In this narrative and systematic review, we present the current evidence available on the role of polymorphisms in genes involved in vein wall remodeling and other pathways as contributors to chronic venous disease. We searched the EMBASE, Medline, and PubMed databases from inception to 2013 for basic science or clinical studies relating to genetic associations in chronic venous disease and obtained 38 relevant studies for this review. Important candidate genes/proteins include the matrix metalloproteinases (extracellular matrix degradation), vascular endothelial growth factors (angiogenesis and vessel wall integrity), FOXC2 (vascular development), hemochromatosis (involved in venous ulceration and iron absorption), and various types of collagen (contributors to vein wall strength). The data on associations between these genes/proteins and the postthrombotic syndrome are limited and additional studies are required. These associations might have future prognostic and therapeutic implications.

Genomics of varicose veins and chronic venous insufficiency

Recent sequencing of the human genome has opened up new areas of investigation for genetic aberrations responsible for the pathogenesis of many human diseases. To date, there have been no studies that have investigated the entire human genome for the genetic underpinnings of chronic venous insufficiency (CVI). Utilizing Gene Chip Arrays we analyzed the relative expression levels of more than 47,000 transcripts and variants and approximately 38,500 well-characterized genes from each of 20 patients (N (CVI)=10; N (Control Group)=10). Relative gene expression profiles significantly differed between patients with CVI and patients unaffected by CVI. Regulatory genes of mediators of the inflammatory reaction and collagen production were up-regulated and down-regulated, respectively in CVI patients. DNA microarray analysis also showed that relative gene expression of multiple genes which function remains to be elucidated was significantly different in CVI patients. Fundamental advancements in our knowledge of the human genome and understanding of the genetic basis of CVI represents an opportunity to develop new diagnostic, prognostic, preventive and therapeutic modalities in the management of CVI.

Diosmin – Isolation Techniques, Determination in Plant Material and Pharmaceutical Formulations, and Clinical Use

Diosmin is a naturally occurring flavone glycoside used in the treatment of venous diseases. In this review, we present the clinical aspects of the use of diosmin preparations in venous stasis, hemorrheologic disorders and vein wall remodeling. Because of its multiple applications in biology and its many therapeutic activities, research on isolation and identification of diosmin is of high relevance. The aim of this review is to present an overview of techniques of isolation and separation of diosmin in plant material, pharmaceutical formulations such as Daflon®, Diosed® and Dioven® tablets, and biological fluids.

Barriers to success: how baculoviruses establish efficient systemic infections

The mechanisms used by baculoviruses to exit the midgut and cause systemic infection of their insect hosts have been debated for decades. After being ingested, baculoviruses reach the midgut, where several host barriers need to be overcome in order to establish successful infection. One of these barriers is the basal lamina, a presumably virus-impermeable extracellular layer secreted by the epithelial cells lining the midgut and trachea. This review discusses new evidence that demonstrates how these viruses breach the basal lamina and establish efficient systemic infections. The biochemical mechanisms involved in dismantling basal lamina during baculovirus infection may also provide new insights into the process of basal lamina remodeling in invertebrate and vertebrate animals.

Viral fibroblast growth factor, matrix metalloproteases, and caspases are associated with enhancing systemic infection by baculoviruses

Most arthropod-borne and invertebrate viruses are orally ingested and commence infection in cells of the invertebrate intestine. Infection of secondary sites and eventual transmission to other hosts is hindered by basal lamina, a tightly interwoven and virus-impenetrable noncellular layer, lining the intestine and other organ cell layers. The mechanisms for viral escape across basal laminae are unknown. We describe an elegant mechanism mediated by a baculovirus-encoded fibroblast growth factor (vFGF) that signals a previously undescribed stepwise cascade of protease activation wherein matrix metalloproteases activate effector caspases, leading to remodeling of basal lamina lining tracheal cells associated with the intestine and culminating in the establishment of efficient systemic infections. Because FGFs coordinate diverse functions during development, metabolic processes, and tissue repair, it is plausible that the vFGF-mediated pathway described here is widely used during developmental and pathogenic processes that involve basal lamina remodeling.