Increased mast cell infiltration in varicose veins of the lower limbs: a possible role in the development of varices

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.

Ligustrazine mitigates chronic venous disease-induced pain hyperalgesia through desensitization of inflammation-associated TRPA1 activity in DRG

ETHNOPHARMACOLOGICAL RELEVANCE

Ligustrazine, an important active ingredient extracted from Ligusticum chuanxiong hort, has been widely used to cure cardiovascular diseases and exerts an analgesic effect.

AIMS OF THIS STUDY

The aim of this study is to investigate whether ligustrazine mitigates chronic venous disease (CVeD)-induced pain and to explore its underlying mechanisms.

MATERIALS AND METHODS

A mouse model of CVeD was established by vein ligature. Ligustrazine was administered intraperitoneally to CVeD mice for a single injection (20 mg/kg, 100 mg/kg, and 200 mg/kg) or once a day for three weeks (100 mg/kg and 200 mg/kg), and TRPA1 overexpressed HEK 293 cells were treated with ligustrazine (600 μM) in the presence of mustard oil (100 μM) for 2 min. Patch clamp and calcium imaging were used to measure the inhibitory response of ligustrazine on DRG neurons and TRPA1 transfected HEK293 cells.

RESULTS

The present results showed that mice receiving vein ligature surgery exhibited obvious pain hypersensitivity to mechanical, cold and thermal stimuli, whereas ligustrazine significantly reversed the pain hyperalgesia in CVeD mice. Furthermore, ligustrazine desensitized transient receptor potential ankyrin 1 (TRPA1) activity in the dorsal root ganglion (DRG) neurons, resulting in suppressing the DRG neuronal excitability in the CVeD mice. However, ligustrazine could not directly inhibit the response of TRPA1 transfected HEK293 cells to mustard oil. Strikingly, ligustrazine restricted the macrophage infiltration and decreased the mRNA levels of Interleukin-1β (IL-1β) and NOD-like receptor protein 3 (NLRP3) in the DRG neurons of the CVeD mice.

CONCLUSIONS

The present study provided evidence that ligustrazine alleviated pain hypersensitivity to mechanical, cold and thermal stimuli in CVeD mice. Ligustrazine could weaken the activity of TRPA1 in the DRG to mitigate CVeD-induced pain hyperalgesia mainly through inhibition of inflammation. Our findings identify that ligustrazine may be a new therapeutic agent for the treatment of CVeD-induced pain.

Characterization of Mast Cells from Healthy and Varicose Human Saphenous Vein

Mast cells (MCs) are distributed in tissues throughout the body and are highly involved in many physiological and pathophysiological processes. The potential and involvement of different MC phenotypes are still not well understood. MCs are present in blood vessel walls, but their specific phenotypic features are unknown. We aimed at characterizing MCs from human saphenous veins for localization, mediator content, and receptor expression. This was done in MCs from both healthy and varicose human saphenous veins (hSV and vSV, respectively). For both vSV and hSV, we found that vein MCs are mainly present in the tunica adventitia (99% MCs in adventitia) and that the population consists of both MCT and MCTC phenotypes (vSV: 55% MCT, hSV: 64% MCT). The vein MCs contained high levels of histamine (vSV: 27 pg/MC, hSV: 55 pg/MC) and tryptase (vSV: 98 pg/MC, hSV: 111 pg/MC), indicating a strong potential for regulatory effects on blood vessels. The receptor expression of FcɛRI, MRGPRX2, PTAFR, C3aR, and C5aR was found, even though the percentage of positive cells differed between vSV and hSV MCs. We conclude that vein MCs from the blood vessel wall have a high potential to affect the tissue around them.

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.

Chronic Venous Disease and the Leukocyte-Endothelium Interaction: From Symptoms to Ulceration

The mechanisms regulating varicose vein development and the subsequent skin sequelae seen in chronic venous disease (CVD) have been investigated recently. Despite the diversity of signs and symptoms associated with the disease, it seems likely that they are related to venous hypertension. Valvular incompetence is the most important cause of venous hypertension. Recent findings suggest that inflammatory processes are involved in the structural remodeling in venous valves and in the vein wall, leading to valvular incompetence and the development of varicose veins. This has been shown by Ono and colleagues, who found infiltration of valve leaflets and the venous wall by leukocytes (monocytes and tissue macrophages) in all valve specimens from patients with CVD and in none from controls. Further work by Takase and colleagues confirmed this hypothesis. Vein wall remodeling is likely to involve the complex interplay of a range of factors, including an altered ratio between metalloproteinases (MMPs) and their tissue inhibitors (TIMPs), and elevated levels of cytokines and growth factors favor an alteration of the extracellular matrix. Neutrophils and mast cells and their interaction with the venous endothelium are believed to play an important role in the initiation of the inflammatory response in CVD. The transmission of high venous pressures to the dermal microcirculation results in the stimulation of an inflammatory process in which cytokine and growth factor release leads to leukocyte migration into the interstitium and the initiation of further inflammatory events. This process is associated with the intense dermal fibrosis and tissue remodeling seen in chronic venous insufficiency. The many manifestations of the disease are frequently associated with symptoms usually ascribed to CVD. The proportion of patients with symptoms increases with increasing CEAP clinical classes, but the mechanisms underlying symptom appearance have not been elucidated. It has been postulated that it is related to the inflammatory cascade of events seen at all stages of CVD and in which the leukocyte and its interaction with the endothelium play a key role. It is increasingly believed that the emerging twin themes of disturbed venous flow patterns and chronic inflammation underlie and link all the manifestations of the disease. Among the many pathophysiologic mechanisms at work, the leukocyte-endothelium interactions seem to be important in many aspects of the disease and have been identified as a possible target for pharmacologic intervention. Pharmacologic agents that could attenuate various elements of the inflammatory cascade and inhibit the inflammatory process might offer a greater opportunity to prevent future morbidity. It seems reasonable to speculate that such treatment could reduce the risk of CVD progression if applied as soon as the first symptoms appear.

Patterns of Venous Reflux and Obstruction in Patients With Skin Damage Due to Chronic Venous Disease

Identified were characteristics of individuals with skin damage related to chronic venous disease. Patients with chronic venous disease (n = 164) were evaluated with duplex ultrasound imaging and were placed in classes 4, 5, and 6 according to the CEAP classification. Their findings were compared with 100 class 2 controls. The prevalence of deep venous thrombosis was higher in the study group (23.7%) versus controls (5.1%; P < .0001), as was the prevalence of deep, perforator, and combined patterns of disease ( P < .0001, P < .0007, and P < .0001). The mean duration of disease in controls 2 was shorter compared with the study group ( P = .0019). The prevalence of reflux and obstruction within the study group was higher than in controls ( P = .0021). Skin changes accurately reflect severity of chronic venous disease. Superficial and perforator vein reflux is the major cause of disease.

An in Vitro Model for the Molecular Investigation of Varicose Veins: Use of Cultured Explants of Human Long Saphenous Vein

Objective:

To develop an in vitro model from explants of human varicose veins (VVs).

Procedures:

Segments of VVs were cultured for up to 14 days with 30% fetal calf serum. At 7 and 14 days, segments were analysed for changes in intima:media thickness and by immunohistochemistry. Comparisons were made with VVs at isolation and cultured explants of normal vein.

Results:

At isolation, VVs had a significantly thicker intima than normal veins ( p<0.001). By day 7 in culture, normal veins developed a significant (smooth muscle cell-derived) ‘neo-intima’ ( p<0.006). In contrast, in VVs there was little change in the intima but a significant increase in the thickness of the media ( p<0.001). Following 14 days in culture, both the neo-intima in normal veins and thickened media in VVs had regressed. Overall, there was a reduction in the intima:media ratio in VVs by day 14 ( p<0.03).

Conclusions:

Segments of VVs can be maintained in culture for up to 14 days without developing a neo-intima and may provide a suitable model to investigate mechanisms underlying the chronic venous insufficiency of varicosity.

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.

Evidence for unmyelinated C fibres and inflammatory cells in human varicose saphenous vein

The physiopathology of venous symptoms, such as pain, leg heaviness or swelling sensations, in chronic venous disease (CVD) remains unclear. Localized release of proinflammatory mediators appears to play a key role but the presence of nociceptors sensitive to inflammatory mediators, such as unmyelinated C fibres, needs to be demonstrated. The present study included 10 patients with documented CVD who underwent surgery for saphenectomy. For each patient, five segments of the great saphenous vein were immunostained with anti-S100 protein and anti-CD45 to identify nerve fibres and inflammatory cells, respectively. Light microscopy was completed by electron microscopy. In all patients, S100 immunopositive nerve fibres and CD45 immunopositive cells were observed. Under an electron microscope, advanced signs of wall remodelling were systematically observed. The density of nerve fibres was low and variable from one sample to another. Unmyelinated C fibres were mainly located in the external part of the media and to a lesser extent in the internal part of the adventitia. Inflammatory cells, mainly histiocytes, were scattered in the media. Mast cells were observed in three patients. In conclusion, unmyelinated C fibres and inflammatory cells are present in the varicose saphenous vein wall. Their linked roles in symptoms of CVD should be further explored.

Assessment of the infiltration of inflammatory cells in the walls of thrombotic varicose veins

The purpose of this study is to describe the infiltration of mast cells as well as T and B cells in the walls of thrombotic varicose great saphenous veins. Sections were obtained from venous segments of patients with varicose veins and stained with toluidine blue for mast cells, while immunohistochemistry for T cells (using CD45RO antibody) and B cells (CD20) was analyzed using light microscopy after staining. The number of mast cells, T, and B cells observed in thrombotic varicose veins was 1.925 ± 1.203, 72.038 ± 34.707, and 19.519 ± 9.899, respectively. In varicose veins, the corresponding values were 0.265 ± 0.099, 0.600 ± 0.432, and 0.488 ± 0.400. Significantly higher number of mast cells, T cells, and B cells were observed in thrombotic varicose veins compared with control veins. A significant difference was not observed between the varicose group and control group. Thrombi in varicose veins can induce infiltration of mast cells, T cells, and B cells, which may be involved in the remodeling of venous walls.

Effects of disturbed flow on vascular endothelium: pathophysiological basis and clinical perspectives

Vascular endothelial cells (ECs) are exposed to hemodynamic forces, which modulate EC functions and vascular biology/pathobiology in health and disease. The flow patterns and hemodynamic forces are not uniform in the vascular system. In straight parts of the arterial tree, blood flow is generally laminar and wall shear stress is high and directed; in branches and curvatures, blood flow is disturbed with nonuniform and irregular distribution of low wall shear stress. Sustained laminar flow with high shear stress upregulates expressions of EC genes and proteins that are protective against atherosclerosis, whereas disturbed flow with associated reciprocating, low shear stress generally upregulates the EC genes and proteins that promote atherogenesis. These findings have led to the concept that the disturbed flow pattern in branch points and curvatures causes the preferential localization of atherosclerotic lesions. Disturbed flow also results in postsurgical neointimal hyperplasia and contributes to pathophysiology of clinical conditions such as in-stent restenosis, vein bypass graft failure, and transplant vasculopathy, as well as aortic valve calcification. In the venous system, disturbed flow resulting from reflux, outflow obstruction, and/or stasis leads to venous inflammation and thrombosis, and hence the development of chronic venous diseases. Understanding of the effects of disturbed flow on ECs can provide mechanistic insights into the role of complex flow patterns in pathogenesis of vascular diseases and can help to elucidate the phenotypic and functional differences between quiescent (nonatherogenic/nonthrombogenic) and activated (atherogenic/thrombogenic) ECs. This review summarizes the current knowledge on the role of disturbed flow in EC physiology and pathophysiology, as well as its clinical implications. Such information can contribute to our understanding of the etiology of lesion development in vascular niches with disturbed flow and help to generate new approaches for therapeutic interventions.

The inflammatory reaction during chronic venous disease of lower limbs

Chronic venous disease (CVD) is an insufficiency of distal veins caused by their partial or total obstruction, endothelial distension and functional disorders. Chronic venous disease of lower limbs is common problem and affects millions of people. In this article we suggest that inflammatory process is involved in the structural remodeling in venous valves and in the venous wall, leading to valvular incompetence and the development of varicose veins.

Pathogenesis of primary varicose veins

BACKGROUND

Valvular incompetence and reflux are common features of primary varicose veins, and have long been thought to be their cause. Recent evidence, however, suggests that changes in the vein wall may precede valvular dysfunction.

METHODS

A literature search was performed using PubMed and Ovid using the keywords 'varicose vein wall changes', 'pathogenesis', 'aetiology' and 'valvular dysfunction'. Articles discussing the pathophysiology of complications of varicose veins, such as ulceration, recurrence, thrombophlebitis and lipodermatosclerosis, were excluded.

RESULTS AND CONCLUSION

Positive family history, age, sex and pregnancy are important risk factors for varicose vein formation. Areas of intimal hyperplasia and smooth muscle cell proliferation are often noted in varicose veins, although regions of atrophy are also present. The total elastin content in varicose as opposed to non-varicose veins is reduced; changes in overall collagen content are uncertain. Matrix metalloproteinases (MMPs), including MMP-1, MMP-2, MMP-3, MMP-7 and MMP-9, and tissue inhibitor of metalloproteinase (TIMP) 1 and TIMP-3 are upregulated in varicose veins. Activation of the endothelium stimulates the recruitment of leucocytes and the release of growth factors, leading to smooth muscle cell proliferation and migration. Dysregulated apoptosis has also been demonstrated in varicose veins. An understanding of the pathophysiology of varicose veins is important in the identification of potential therapeutic targets and treatment strategies.

Varicose veins show enhanced chemokine expression

OBJECTIVES

Leucocyte infiltration in the wall of varicose veins has been reported previously. This study was designed to investigate the expression of pro-inflammatory cytokines and chemokines in control and in patients with varicose veins and to test the effect of treating varicose vein patients with acetylsalicylic acid (ASA) on cytokine expression prior to removal of varices.

MATERIAL AND METHODS

Sections of vein were removed during operation from both patient groups, and ribonuclease protection assays (RPAs) were performed to assess the expression of chemokines. Group I included non-varicose saphenous veins from healthy patients undergoing amputation for trauma. Varicose veins were obtained from patients with primary varicose undergoing surgical treatment who received no drug (group II) or treatment with 300 mg day(-1) of ASA for 15 days before surgery (group III).

RESULTS

Non-varicose veins constitutively expressed low levels of monocyte-chemoattractant protein (MCP-1) and interleukin (IL)-8 mRNA. Varicose veins had a distinct chemokine expression pattern, since significant up-regulation of MCP-1 and IL-8 and a marked expression of IP-10, RANTES, MIP-1alpha and MIP-1beta mRNA were detected. Removal of the endothelium did not alter this pattern. Varicose veins obtained from patients treated with ASA showed a consistent decrease in chemokine expression, although it did not reach statistical significance.

CONCLUSIONS

Varicose veins showed increased expression of several chemokines compared to control veins. A non-significant reduction of activation was observed following treatment with ASA for 15 days.

TGF-beta1 upregulation in the aging varicose vein

BACKGROUND

Although the etiology of venous insufficiency is not well understood, immune response and aging are beginning to emerge as contributing factors. Factors involved in tissue remodeling such as TGF-beta(1) also seem to play an important role in extracellular matrix production. The aim of this study was to explore the relationship between chronic venous insufficiency and TGF-beta(1) examining the latent/mature form of TGF-beta(1) and the presence of mast cells. Effects of age were also evaluated.

METHODS

Saphenous veins were obtained from patients subjected to aortocoronary bypass (controls) and undergoing varicose vein surgery. These were immunolabeled using anti-LAP TGF-beta(1)/anti-TGF-beta(1) antibodies and subjected to Western blot. Mast cell population was identified by metachromatic staining.

RESULTS

Latent TGF-beta(1) was significantly reduced in varicose veins from older subjects. In contrast, smooth muscle cells obtained from the varicosities showed intense levels. Mature TGF-beta(1) significantly differed between healthy and varicose veins. No mature TGF-beta(1) was detected in the cell cultures. Mast cell number and degranulation were increased with aging and varicose disease, colocalizing with the mature form of TGF-beta(1).

CONCLUSION

Aging and varicose pathology induce dysregulation of TGF-beta(1) that could play an important role in the fibrous process, representing the final stages of venous insufficiency.

Immunocytochemical characterisation of the inflammatory cell infiltrate of varicose veins

OBJECTIVES

To characterise the inflammatory cell infiltrate in varicose vein wall, and its relationship to the valve complex.

DESIGN

A comparative study of the distribution of inflammatory cells in normal and varicose vein.

MATERIALS

Specimens of proximal human long saphenous vein were obtained from patients with duplex Doppler confirmed long saphenous vein reflux (n=14). Control vein was obtained from patients undergoing coronary artery bypass without clinical evidence of venous insufficiency (n=6). Longitudinal 7 microm frozen sections of vein, displaying valve, were prepared.

METHODS

Using immunohistochemistry, T-lymphocytes (CD3), macrophage/monocytes (CD68), neutrophils (CD15s) and mast cells (anti-mast cell tryptase) were identified. The number of cells per unit length vein were counted using light microscopy.

RESULTS

There were significantly more mast cells and macrophage/monocytes in varicose vein as compared to control. There was a non-significant trend towards more T-lymphocytes in varicose vein. Few neutrophils were present in varicose or normal vein. The distribution of inflammatory cells with respect to the valve was not found to be significant.

CONCLUSIONS

Varicose veins display a greater inflammatory cell infiltrate than normal vein. The key role of macrophage/monocytes and mast cells in tissue damage and remodelling should stimulate further research into whether they play a significant role in the development of chronic venous insufficiency.

Primary Varicose Veins: Altered Transcription of VEGF and its Receptors (KDR, flt-1, Soluble flt-1) with Sapheno-femoral Junction Incompetence

OBJECTIVE

Loss of regulation of vascular endothelial growth factor (VEGF) production and action disturbs vascular homeostasis leading to pathology. Primary varicose veins (VVs) demonstrate aberrant production/release of VEGF. Our aim was to examine transcription of genes for VEGF (VEGF(121)/VEGF(165)) and its receptors (KDR, flt-1, s.flt-1) in VVs, in relation to underlying venous incompetence.

MATERIALS AND METHODS

Samples of varicose (n=83, 18 patients) or normal (n=14, five subjects) great saphenous vein were divided into segments, determined by anatomical position from the sapheno-femoral junction (SFJ). SFJ and segmental incompetence were determined from duplex scans. Gene transcripts were amplified by RT-PCR, analysed by scanning densitometry, and the levels of transcription determined by ratio to control gene GADPH-3 (GAP-3).

RESULTS

VEGF(121)/(165), KDR and flt-1 transcription was elevated in VVs overall (p<0.001), and in VVs with an incompetent SFJ (p<0.001), but not when the SFJ was functional; s.flt-1 was unaltered. Notably, gene transcription was unaffected by segmental position, or incompetence. Position below the SFJ correlated with increased transcription of s.flt-1 when the SFJ was incompetent (p<0.04), and s.flt-1 and VEGF(121) when the segment was incompetent (p<0.03).

CONCLUSIONS

SFJ incompetence is associated with altered transcription of VEGF and its receptors reflecting an aetiological mechanism or later stage of disease development. Altered VEGF(121) and s.flt-1 transcription may be an early event in varicogenesis.

Mast cell infiltration in the wall of varicose veins

Varicose veins of the lower extremities are abnormally dilated, tortuous and elongated. The exact cause of vein dilatation has still not been established. Mast cells produce, store and release various types of vasoactive compounds (histamine, tryptase, prostaglandins, leukotrienes, and cytokines). Histamine enhances local vasopermeability and smooth muscle cell proliferation, leading to thickening of the intima. Tryptase can contribute to local vascular injury and subsequent weakness of the vascular wall causing varix formation. The aim of the present study was the comparison of mast cell infiltration in the wall of varicose and non-varicose veins. The mean mast cell density in the wall of varicose veins was 0.86 mast cell per mm2 and in healthy non-dilated vein walls, density was 1.23 mast cell per mm2. This difference was not statistically significant, therefore we could not confirm our hypothesis. Nevertheless, we suggest that mast cells could play an important role in the development of varices and the factor released by the mast cells should be further examined.

Varicose veins possess greater quantities of MMP-1 than normal veins and demonstrate regional variation in MMP-1 and MMP-13

BACKGROUND

Studies have reported that structural proteins such as elastin and collagen are decreased in varicose veins compared to normal controls. We hypothesized that the changes observed in varicose vein wall composition may be related to alterations in extracellular matrix remodeling proteins, such as the matrix metalloproteases and serine proteases. In addition we hypothesized that there may be regional variation in the expression of these enzymes within the leg.

PATIENTS AND MATERIALS

One-centimeter segments of the proximal and distal greater saphenous vein (GSV) were obtained from patients undergoing ligation and stripping for venous insufficiency (vv) (n = 15) or GSV harvest in conjunction with coronary artery bypass grafting (CABG) (n = 7). All vv patients had incompetence of the GSV by color flow duplex. Vein specimens were examined for MMP-1, 3, and 13, tryptase, and GAPDH mRNA using semiquantitative RT-PCR analysis. Quantification of MMP-1 and 13 (active/latent forms) and tryptase was performed using Western blot analysis. Western blots were analyzed using scanning densitometry and standardized to normal controls and values expressed as the median densitometric index (D.I.). Nonparametric statistical methods (Wilcoxan signed rank test and Mann-Whitney U test) were used for analysis.

RESULTS

We were able to amplify MMP-1, MMP-13, and tryptase mRNA from both proximal and distal segments of all greater saphenous veins studied. MMP-3 mRNA, however, was not found in either segment of any of the veins examined. A semiquantitative analysis of RT-PCR products comparing the ratio of MMP-1, MMP-13, or tryptase mRNA to GAPDH mRNA showed no difference between cases and controls nor proximal vs distal vein segments. Western blot analysis revealed larger quantities of MMP-1 in varicose veins than in nondiseased veins from CABG patients (48.0 +/- 36.7 D.I. vs 12.5 +/- 6.8 D.I., P = 0.036). Investigation into the regional variation of proteases revealed lower amounts of MMP-1 in distal than in proximal vein segments (37.9 +/- 35.0 D.I. vs 44.1 +/- 41.6 D.I., P = 0.01). Similarly, we found significantly less MMP-13 in distal segments of varicose veins than in proximal segments (152.8 +/- 130.0 D.I. vs 206.7 +/- 173.3 D.I., P = 0.006).

CONCLUSIONS

This study found that MMP-1 protein is increased in varicose veins when compared to controls despite no differences in mRNA expression. In addition we found that there is regional variation of MMP-1 and MMP-13 in diseased varicose veins. Lower leg veins have significantly reduced amounts of these proteolytic enzymes when compared to veins of the upper thigh. These data suggest that posttranscriptional regulatory controls could be responsible for the observed differences.

Generation of reactive oxygen metabolites by the varicose vein wall

OBJECTIVES

to evaluate the content of lipid peroxidation products (expressed by the concentration of thiobarbituric acid-reactive substances; TBARS), the content of myeloperoxidase (MPO), and the localisation of xanthine oxidase (XO) in varicose veins (vv), varicose veins with superficial thrombophlebitis and unchanged saphenous veins.

METHODS

varicose saphenous veins, varicose veins with superficial thrombophlebitis and normal saphenous veins obtained during varicose vein surgery on 36 patients as well as healthy saphenous veins from cadaver organ donors (control). Homogenates were prepared in which TBARS concentration and MPO content were determined. Immunohistochemical staining to detect XO was also performed.

RESULTS

the highest concentration of TBARS occurred in vv with superficial thrombophlebitis, the lowest in donor vein. The highest content of MPO was observed in vv and slightly lower - in varicose veins with thrombophlebitis. A positive reaction for XO was seen in vv wall endothelium. Specimens of vv with thrombophlebitis revealed strong, intense staining in endothelium as well as in vasa vasorum.

CONCLUSIONS

varicose veins, especially those complicated with superficial thrombophlebitis revealed increased free radical generation. Its sources might be neutrophils, and in vv complicated with superficial thrombophlebitis-xanthine oxidase.

Smooth muscle cell modulation and cytokine overproduction in varicose veins. An in situ study

The exact aetiology and physiopathology of varicose disorders remain unclear. The aim of the present work was to study, in situ, the morphology and composition of cellular and matrix components in varicose veins compared with control veins and to identify factors that could contribute to varicose remodelling. A combined histological, immunohistochemical, and biochemical approach was used. Longitudinal sections of varicose (n=12) and control veins (n=9) were studied to assess the organization, structure, and phenotype of smooth muscle cells; the localization of microvascular endothelial cells; the distribution of connective tissue proteins; and the localization of cytokines. These cytokines were further quantified by ELISA. Considerable heterogeneity of the varicose vein wall was observed, with a succession of hypertrophic and atrophic segments, presenting severe disorganization of the medial layer and numerous areas of intimal thickening. In hypertrophic portions, medial smooth muscle cells showed marked alterations suggesting modulation from a contractile to a proliferative and synthetic phenotype; furthermore, the number of vasa vasorum was increased. In contrast, in atrophic portions, both cellular and matrix components were decreased. TGFbeta1 (p< or =0.005) and bFGF (p< or =0.001) were increased and VEGF was not significantly modified in varicose veins when the results were expressed per mg of DNA. These results show that phenotypic modulation of smooth muscle cells, altered extracellular matrix metabolism, and angiogenesis are the main mechanisms contributing to the morphological and functional modifications of varicose remodelling. The increased expression of bFGF and TGFbeta1 by varicose vein cells may play a pivotal role in the hypertrophy of the venous wall, but the exact mechanism leading to aneurysmal dilatations remains to be elucidated.

Expression of adhesion molecules and cytokines on saphenous veins in chronic venous insufficiency

The objective of this study was to assess the relationship of signaling molecules to monocyte/ macrophages as a precursor to venous valve and venous wall dysfunction in patients with varicose veins. One of the hallmarks of venous dysfunction is destruction of venous valves with subsequent reflux and elevation of distal venous pressure. We recently observed that monocytes/macrophages migrate into the venous walls and valves of patients with venous insufficiency. There, they may play a role in the pathogenesis of primary venous insufficiency. If so, an important element in their performance would be the interaction between the monocytes and the endothelium as a precursor of damage to venous valves and the venous wall. To explore this interaction, immunohistochemistry was carried out to detect adhesion molecules and cytokines in surgical specimens removed during surgical therapy. Twenty-four surgical specimens consisting of proximal saphenous vein and subterminal valve were obtained using minimally traumatic technique in 6 males and 18 females who ranged in age from 31 to 79 years. Reflux was confirmed preoperatively by duplex technique, and severity was classified by the CEAP classification of the American Venous Forum. Ten patient limbs were class 2, eight were class 3, four were class 4, and two were class 6. The venous specimens were labeled using monoclonal antibody against ICAM-1, E-selectin, IL-1alpha, and TNF-alpha. CD68 was used for detection of monocytes/macrophages. Our results indicate that not only luminal venous endothelium but also endothelium in the vasa vasora of refluxing saphenous veins is activated, as indicated by the up-regulation of ICAM-1. However, IL-1alpha and TNF-alpha were increased in only selected specimens and are mainly detected in the vein wall. The factors that serve as trigger mechanisms to activate cells in the pathogenesis of primary venous dysfunction remain to be explored.

Glucosamine for migraine prophylaxis?

Following a fortuitous observation that migraine headaches ceased in a patient receiving glucosamine therapy for osteoarthritis, a further ten patients with migraine or migraine-like vascular headaches, refractory to established preventive or abortive therapies, have been treated with daily oral glucosamine. After a lag of 4-6 weeks, a substantial reduction in headache frequency and/or intensity has been noted; in some cases, the benefit appears to be dose-dependent. Since glucosamine can be a rate-limiting precursor for mucopolysaccharide synthesis, it is germane to note previous reports that heparin and pentosan polysulfate may have migraine-preventive activity. There is reason to suspect that mast cells are central mediators of the neurogenic inflammation associated with migraine and cluster headaches. The heparin produced by mast cells may function to provide feedback down-regulation of mast cell activation, and exerts a range of other anti-inflammatory effects. We postulate that supplemental glucosamine can boost mast cell heparin synthesis - perhaps correcting a functional heparin deficiency - thereby preventing or ameliorating the neurogenic inflammation that mediates pain in vascular headache. Whether or not this idea has validity, a controlled study of glucosamine for migraine prophylaxis appears to be warranted.

Increased TIMP/MMP ratio in varicose veins: a possible explanation for extracellular matrix accumulation

Primary varicose veins are functionally characterized by venous back-flow and blood stagnation in the upright position. Dilatation and tortuosity provide evidence for progressive venous wall remodelling, with disturbance of smooth muscle cell/extracellular matrix organization. Affected areas are not uniformly distributed, some areas being hypertrophic, whereas others are atrophic or unaffected. In 12 varicose veins and ten control veins, the proteolytic enzyme/inhibitor balance which may participate in the remodelling of the venous wall was investigated. For this purpose, the presence and enzymatic activity of matrix metalloproteinases (MMP-2, MMP-9), tissue inhibitors of MMPs (TIMP-1, TIMP-2), urokinase-type (uPA) and tissue-type (tPA) plasminogen activators (PAs), and plasminogen activator inhibitor-1 (PAI-1) were quantified by western blot and gelatin or plasminogen-casein zymography. In addition, MMP-2, TIMP-1, TIMP-2, and PAI-1 levels were measured by ELISA. A high TIMP-1 level and a low MMP-2 level/activity were found in varicose veins (p<0.005), resulting in a three-fold increase in the TIMP-1/MMP-2 ratio in varicose versus control veins. Levels of PAs (uPA and tPA) as well as PAI-1 were both lower in varicose veins (p<0.005), with minimal change in the PAI/PA ratio. These results demonstrate that varicose veins are characterized by a higher than normal TIMP/MMP ratio, which may facilitate extracellular matrix accumulation in the diseased venous wall.

Programmed cell death (Apoptosis) and its role in the pathogenesis of lower extremity varicose veins

The etiology of varicose veins remains elusive. We hypothesized that abnormal cell cycle events in the vein wall may contribute to changes in its structural integrity predisposing to varicosity development. Since cell cycle checkpoint controls are linked to the signaling and execution of apoptotic cascades, possibly apoptosis is a contributing factor in the pathophysiology of varicosities. The present study was designed to investigate whether programmed cell death varies in varicosities as compared to normal veins. Twenty-seven normal greater saphenous vein specimens were obtained from patients undergoing infrainguinal arterial bypass surgery, and 20 varicose vein specimens were retrieved from patients undergoing varicose vein excision. Apoptosis was detected by TUNEL assay. Expression of bcl-2 and cyclin D1 was noted by standard immunohistochemical techniques. Apoptotic cells were identified in 32 of the 47 specimens. Forty-eight percent of normal vein specimens displayed >3 apoptotic cells per 100 cells in the adventitia; 15% of the specimens of the varicose vein group showed such magnitude of apoptosis (p < 0.03). This increased apoptotic activity was not observed in media or intima of either vein group (p < 0.001). No significant difference in immunoreactivity to bcl-2 protein was observed in varicose vein specimens as compared to controls. Varicose vein specimens demonstrated increased nuclear expression of cyclin D1 whereas its cytoplasmic expression was significantly diminished (p </=0.02). These data show that programmed cell death is inhibited in varicose veins. Differential expression of cyclin D1 suggests that it may deregulate cell cycle events, thereby leading to varicosity formation.

Dendritic cells in venous pathologies

Dendritic cells are potent antigen-presenting cells responsible for the activation of T-lymphocytes in various immune responses. Their role in the initiation of immune reactions in allergies, autoimmune diseases, tumors, transplantation, and, more recently, in atherosclerosis has been well established, but their involvement in venous pathologies has not been previously investigated. The aim of this study was to determine whether dendritic cells are present in veins affected by varicosity and thrombophlebitis. Three groups of veins obtained at operation were studied: (1) varicose veins of the great saphenous vein from patients who were undergoing vein stripping for primary varicosity; (2) segments of the great saphenous vein from patients with varicosity complicated by thrombophlebitis; and (3) great saphenous veins without varicosity or thrombophlebitis from patients who were undergoing femoropopliteal bypass grafting. The specimens were fixed in 10% neutral buffered formalin and embedded in paraffin, and the sections were stained with antibodies to S-100 (to identify dendritic cells), CD3 (T-lymphocytes), CD68 (macrophages), von Willebrand factor (endothelial cells), alpha-smooth muscle actin (smooth muscle cells), and CD15 (mast cells) by use of avidin-biotin complex (ABC) immunoperoxidase technique. Immunohistochemical examination showed that no S-100-positive dendritic cells were present in normal saphenous veins. In contrast, S-100-positive cells with dendritic cell morphology were detected in the intima and media of veins with varicosity and thrombophlebitis, where they represented a minor cell population. S-100-positive dendritic cells were located between smooth muscle cells as well as around areas of neovascularization where they colocalized with T-lymphocytes. The present work suggests that dendritic cells might be involved in pathological processes in veins affected by varicosity and thrombophlebitis. The authors speculate that dendritic cells may be involved in the inflammatory mechanisms in these veins through their interaction with T-lymphocytes.

Tissue inhibitor of metalloproteinase-1 is increased in the saphenofemoral junction of patients with varices in the leg

PURPOSE

The goal of the present study was to examine the role of matrix metalloproteinase (MMP) activity in the development of varicose changes in the superficial veins of the lower extremity.

METHODS

Normal-caliber vein segments from the saphenofemoral junction were harvested from patients undergoing saphenous vein ligation for varices and from patients undergoing infrainguinal bypass graft procedures. The activity and quantity of MMPs and their inhibitors (tissue inhibitors of metalloproteinases [TIMPs]) in the vein segments were compared. Vein segments were obtained from 13 patients. Seven patients had varicose disease in the leg, including 6 women and 1 man (average age, 48 years). Six patients had no evidence of varicose disease, including 2 women and 4 men (average age, 59 years). Proteolytic activity was determined with substrate gel zymography, and enzyme content was determined with Western immunoblotting using monoclonal antibodies directed against MMP-2, MMP-3, MMP-9, TIMP-1, TIMP-2, and alpha2-macroglobulin. Signals were quantified by scanning densitometry and normalized to a positive control (densitometric index [DI]). Immunohistochemistry was performed for enzyme localization.

RESULTS

Zymography did not detect a difference between groups at loci consistent with the major MMPs; however, a small but significant decrease in proteolytic activity was noted in veins from patients with varices. TIMP-1 is increased in vein segments from patients with varices (DI 0.8 +/- 0.1 vs 0.2 +/- 0.05, P < .05) while MMP-2 levels were decreased (DI 1.5 +/- 0.3 vs 0.5 +/- 0.1, P < .05). Immunohistochemistry localized MMPs to the adventitia of the vein wall.

CONCLUSION

A decrease in proteolytic activity may be responsible for the histological and structural alterations leading to varicose degeneration of superficial lower extremity veins.