Implication of the PI3K/Akt/mTOR Pathway in the Process of Incompetent Valves in Patients with Chronic Venous Insufficiency and the Relationship with Aging

Chronic venous insufficiency (CVI) is a multifactorial disease, commonly caused by valvular incompetence (clinically diagnosed by venous reflux) and venous hypertension. The incidence of these factors clearly increases with patient age, and aging is one of the risk factors involved. The activity of the PI3K/Akt/mTOR pathway is considered fundamental in vascular pathologies, and understanding its involvement would help in the development of possible therapeutic targets. This is an observational, analytical, and prospective cohort study that reviewed 110 patients with CVI scheduled to undergo stratified saphenectomy. They were distributed according to the presence (R = 81) or absence (NR = 29) of valvular incompetence (venous reflux) diagnosed clinically. Each of the groups was further divided according to age, with a cutoff point of 50 years (NR < 50 = 13, NR ≥ 50 = 16, R < 50 = 32, and R ≥ 50 = 49). The involvement of the PI3K/Akt/mTOR pathway, as well as that of HIF-1α and HIF-2α and of CD4+, CD8+, and CD19+ cells and mastocytes, was assessed. Saphenous vein tissue samples obtained during surgery were processed for RT-qPCR and immunohistochemistry. Patients with venous reflux showed a significant increase in mRNA and protein expression levels for PI3K/mTOR and HIF-1α/HIF-2α. The number of mast cells was significantly elevated in the R group. In distribution by age, PI3K/Akt/mTOR and HIF-1α were significantly higher in R < 50 patients. Furthermore, these patients had a significant increase in the number of CD4+, CD8+, and CD19+ cells and mastocytes in the saphenous vein wall. These findings provide a basis for the possible existence of changes in PI3K/Akt/mTOR pathway expression in young patients, with potential accelerated asynchronous aging that is enhanced by CVI.

Venous insufficiency: Differences in the content of trace elements. A preliminary report

BACKGROUND

Venous insufficiency is still a serious clinical problem. The exact cause and molecular mechanisms of this disease are still unknown. In this study, we try to identify whether there is a difference in the level of trace elements between healthy and pathological veins. Our results show that insufficient veins have different levels of some trace elements: magnesium, calcium, manganese, and silicon compared to control samples. This study could lead to a better understanding of the molecular causes of venous insufficiency and may help to develop better methods of treatment.

OBJECTIVES

Nowadays, venous diseases are a very common clinical phenomenon. Venous insufficiency is thought to be one of the most common vein diseases. The exact mechanisms of its etiology are still unknown, although from a clinical point of view some risk factors include gender, age, changing hormone levels, heredity, and standing or sitting for long periods. An imbalance in trace elements could also play a crucial role in the development and/or progression of venous insufficiency.

MATERIAL AND METHODS

The trace element content in varicose vein walls and in normal vein walls was measured using an inductively coupled plasma-optical emission spectrometer (ICP-OES) after sample mineralization. Statistical analysis (the Mann-Whitney U test and the Friedman ANOVA) was performed to compare insufficient veins to controls (healthy veins).

RESULTS

This study found statistically significant higher magnesium (Mg) ion levels in varicose veins compared to controls (p = 0.0067) and differences close to statistical significance in calcium (Ca), manganese (Mn), and silicon (Si) ion levels.

CONCLUSIONS

The results obtained could indicate oxidative stress occurring in chronic venous insufficiency as well as free radical neutralization pathways due to superoxide dismutase (SOD) activity with Mg, Mn and copper (Cu) ion involvement. Our results are consistent with literature data and are preliminary in nature.

Skin Damage in Chronic Venous Insufficiency: Does an Oxygen Diffusion Barrier Really Exist?

Eleven patients with lipodermatosclerosis (LDS) and 14 patients without venous or arterial disease underwent measurement of xenon-133 (133Xe) half-clearance times from the gaiter region of the leg. Xenon has similar diffusion characteristics to oxygen, and the investigation reflects the ability of the isotope to diffuse from the skin surface into capillary blood. Median skin half-clearance time for skin in the LDS group was 2.2 min and in the control group 2.1 min. From the subcutaneous tissues, the respective times were 14.1 and 17.4 minutes. These differences are not statistically significant. The study fails to yield evidence suggesting that an oxygen diffusion barrier exists in lipodermatosclerosis.

TGF-β1 in Vascular Wall Pathology: Unraveling Chronic Venous Insufficiency Pathophysiology

Chronic venous insufficiency and varicose veins occur commonly in affluent countries and are a socioeconomic burden. However, there remains a relative lack of knowledge about venous pathophysiology. Various theories have been suggested, yet the molecular sequence of events is poorly understood. Transforming growth factor-beta one (TGF-β1) is a highly complex polypeptide with multifunctional properties that has an active role during embryonic development, in adult organ physiology and in the pathophysiology of major diseases, including cancer and various autoimmune, fibrotic and cardiovascular diseases. Therefore, an emphasis on understanding its signaling pathways (and possible disruptions) will be an essential requirement for a better comprehension and management of specific diseases. This review aims at shedding more light on venous pathophysiology by describing the TGF-β1 structure, function, activation and signaling, and providing an overview of how this growth factor and disturbances in its signaling pathway may contribute to specific pathological processes concerning the vessel wall which, in turn, may have a role in chronic venous insufficiency.

[Chronic venous diseases: valvular function and leukocyte-endothelial interaction, possibilities of pharmacotherapy]

This article provides a review of the literature focusing on the data elucidating the pathogenesis of chronic venous diseases from the positions of macrohaemodynamic (venous valvular function) and microcirculatory impairments. Presented herein are confirmations of the interaction between two important mechanisms, as well as the literature data concerning the role of the venous microvalvular structures and possible haemodynamic impairments in functional venous insufficiency. Also presented are substantiations in confirmation of the theory of leukocyte-endothelial interaction, forming the basis for contemporary understanding of the pathogenesis of chronic venous diseases. This is followed by elucidating the role of venoactive drugs in conservative treatment of patients with chronic venous diseases, and, finally, touching upon current problems and promising approaches to solve them.

[Possibilities of pharmacotherapy for chronic venous insufficiency with diosmin preparations from the position of the endothelial functional state]

Despite a high level of the development of modern angiology and vascular surgery, the problem of chronic venous insufficiency (CVI) complicating the course of various venous diseases seems to have no tendency towards being solved, thus calling forth permanent search for optimization of methods of treatment and rehabilitation of patients presenting with the above-mentioned syndrome. The article presents a review of contemporary studies dedicated to the problem of correcting CVI. Special attention is paid to the endothelial state in CVI and possibilities of correcting endothelial dysfunction with the use of bioflavonoids, in particular, diosmin. Also presented herein are the results of an original experimental study dedicated to peculiarities of the endothelial functional state, endothelial dysfunction, and correction thereof on the background of the existing CVI.

Glycosaminoglycan sulodexide modulates inflammatory pathways in chronic venous disease

Inflammation represents an important epiphenomenon in the etiopathogenesis of chronic venous disease, a worldwide debilitating condition affecting millions of subjects. The pathophysiology of chronic venous disease (CVD) is based on the hemodynamic abnormalities in conjunction to alterations in cellular and extracellular matrix biocompounds. The endothelial dysfunction results from early perturbation in the endothelium linked to glycocalyx injury and promoted by inflammatory cells and mediators (such as matrix metalloproteinases and interleukins), which lead to progressive dilation of the vein resulting in chronic venous insufficiency. Activated leukocytes during the inflammatory process release enzymes, free radicals, chemokines and inflammatory cytokines in the vessel microenvironment, which are responsible for the changes of the venous wall and venous valve, reflux and venous hypertension, and the development/progression of tissue destruction and skin changes. Sulodexide, a highly purified mixture of glycosaminoglycans composed by 80% fast moving heparin and 20% of dermatan sulphate, exhibits anti-thrombotic and profibrinolytic properties, restoring also the essential endothelial glycocalyx. Glycosaminoglycan sulodexide has been also characterized to reduce the release of inflammatory cytokines/chemokines and to inhibit the matrix metalloproteinases-related proteolytic cascades, counteracting endothelial dysfunctions. The pleiotropic effects of sulodexide set the basis for a very promising agent in treating the spectrum of CVD.

Pathophysiology of chronic venous disease

Chronic venous disease (CVD) is a debilitating condition with a prevalence between 60-70%. The disease pathophysiology is complex and involves genetic susceptibility and environmental factors, with individuals developing visible telengiectasias, reticular veins, and varicose veins. Patient with significant lower extremity symptoms have pain, dermal irritation, swelling, skin changes, and are at risk of developing debilitating venous ulceration. The signature of CVD is an increase in venous pressure referred to as venous hypertension. The various symptoms presenting in CVD and the clinical signs that are observed indicate that there is inflammation, secondary to venous hypertension, and it leads to a number of inflammatory pathways that become activated. The endothelium and glycocalyx via specialized receptors are critical at sensing changes in shear stress, and expression of adhesion molecules allows the activation of leukocytes leading to endothelial attachment, diapedisis, and transmigration into the venous wall/valves resulting in venous wall injury and inflammatory cells in the interstitial tissues. There is a complex of cytokines, chemokines, growth factors, proteases and proteinases, produced by activated leukocytes, that are expressed and unbalanced resulting in an environment of persistent inflammation with the clinical changes that are commonly seen, consisting of varicose veins to more advanced presentations of skin changes and venous ulceration. The structural integrity of protein and the extracellular matrix is altered, enhancing the progressive events of CVD. Work focusing on metabolic changes, miRNA regulation, inflammatory modulation and the glycocalyx will further our knowledge in the pathophysiology of CVD, and provide answers critical to treatment and prevention.

Generation of reactive oxygen species by a sufficient, insufficient and varicose vein wall

Despite numerous theories, the etiology and pathogenesis of primary varicose veins remain unclear. The etiology of chronic venous diseases (CVDs) known as chronic venous insufficiency (CVI) is related to leukocyte trapping. Leukocyte trapping involves trapping of white cells in vessel walls followed by their activation and translocation outside the vessel. Release of reactive oxygen species (ROS) from trapped white cells has been documented. Superoxide dismutase (SOD) directly inhibits the generation of free radicals and compounds that are produced during oxidation by ROS, such as malonyldialdehyde (MDA). The aim of this study was to determine the involvement of free radicals in the etiology of venous changes. The following material was used for the study: fragments of sufficient or insufficient venous system and varices from 31 patients diagnosed with chronic venous disease in the 2nd or 3rd degree, according to clinical state, etiology, anatomy and pathophysiology (CEAP), which were qualified for surgical procedure. The levels of oxidative stress markers strongly correlated with lesions observed by USG in insufficient and varicose veins. In both a higher concentration of MDA was observed, which is a sign of lipid peroxidation. Antioxidative mechanisms, SOD activity and total antioxidative power expressed as FRAP were inversely proportional to MDA concentration. In insufficient and varicose veins both FRAP and SOD activities were significantly lower than in normal veins. The severity of clinical changes was inversely dependent on the efficiency of scavenging of ROS, which additionally proves the participation of free radicals in pathogenesis of CVDs.

Chronic cerebrospinal venous insufficiency and iron deposition on susceptibility-weighted imaging in patients with multiple sclerosis: a pilot case-control study

AIM

Chronic cerebrospinal venous insufficiency (CCSVI) is a vascular phenomenon recently described in multiple sclerosis (MS) that is characterized by stenoses affecting the main extracranial venous outflow pathways and by a high rate of cerebral venous reflux that may lead to increased iron deposition in the brain. Aim of this study was to investigate the relationship between CCSVI and iron deposition in the brain of MS patients by correlating venous hemodynamic (VH) parameters and iron concentration in deep-gray matter structures and lesions, as measured by susceptibility-weighted imaging (SWI), and to preliminarily define the relationship between iron measures and clinical and other magnetic resonance imaging (MRI) outcomes.

METHODS

Sixteen (16) consecutive relapsing-remitting MS patients and 8 age- and sex-matched healthy controls (HC) were scanned on a GE 3T scanner, using SWI.

RESULTS

All 16 MS patients fulfilled the diagnosis of CCSVI (median VH=4), compared to none of the HC. In MS patients, the higher iron concentration in the pulvinar nucleus of the thalamus, thalamus, globus pallidus, and hippocampus was related to a higher number of VH criteria (P<0.05). There was also a significant association between a higher number of VH criteria and higher iron concentration of overlapping T2 (r=-0.64, P=0.007) and T1 (r=-0.56, P=0.023) phase lesions. Iron concentration measures were related to longer disease duration and increased disability as measured by EDSS and MSFC, and to increased MRI lesion burden and decreased brain volume.

CONCLUSION

The findings from this pilot study suggest that CCSVI may be an important mechanism related to iron deposition in the brain parenchyma of MS patients. In turn, iron deposition, as measured by SWI, is a modest-to-strong predictor of disability progression, lesion volume accumulation and atrophy development in patients with MS.

Iron stores and cerebral veins in MS studied by susceptibility weighted imaging

AIM

In this paper, we seek to determine whether the iron deposition as seen by susceptibility weighted imaging (SWI) in the basal ganglia and thalamus of patients with multiple sclerosis is greater than the iron content measured in normal subjects (individuals unaffected by multiple sclerosis). As increased iron content may result from increased venous pressure, such information would add credence to the concept of Zamboni et al (1) that MS is caused by chronic cerebrospinal venous insufficiency.

METHODS

Fourteen MS patients were recruited for this study with a mean age of 38 years ranging from 19 to 66 year-old. A velocity compensated 3D gradient echo sequence was used to generate SW images with a high sensitivity to iron content. We evaluated iron in the following structures: substantia nigra, red nucleus, globus pallidus, putamen, caudate nucleus, thalamus and pulvinar thalamus. Each structure was broken into two parts, a high iron content region and a low iron content region. The measured values were compared to previously established baseline iron content in these structures as a function of age.

RESULTS

Twelve of fourteen patients had an increase in iron above normal levels and with a particular pattern of iron deposition in the medial venous drainage system that was associated with the confluence of the veins draining that structure.

CONCLUSION

Iron may serve as a biomarker of venous vascular damage in multiple sclerosis. The backward iron accumulation pattern seen in the basal ganglia and thalamus of most MS patients is consistent with the hypothesis of venous hypertension.

[Role of Zn, Cu--trace elements and superoxide dismutase (SOD) in oxidative stress progression in chronic venous insufficiency (CVI)]

INTRODUCTION

Ions of trace elements, zinc and copper, play a key role in a number of vital signs and metabolic processes occurring in human organism. In venous vessels, Cu and Zn ions contribute to formation of free oxygen radicals (catalysts for Habera-Weisa reaction) and may result in development of changes leading to chronic venous disease (CVD), also known as chronic venous insufficiency (CVI). These elements lead to changes occurring in cells by contributing to lipid peroxidation process. As enzyme activators, Zn and Cu ions maintain proper cell membranes functioning. In addition, these ions create the catalytic center of one of the most important enzymes of the antioxidant defence system, superoxide dismutase (SOD). THE AIM OF THE PRESENT STUDY: The aim of the present study was determination of copper and zinc ions in sufficient and insufficient vessels lyophilized and varicose veins lyophilized from patients with CVD. Further, a comparison of SOD activity in homogenates of above-mentioned tissues was done.

MATERIALS AND METHODS

Study material consisted of tissues lyophilized and homogenates. This material contained: - Insufficient vessels originating from area of saphenous vein ostium (VSM, vena saphe magna), where venous insufficiency with massive venous reflux was observed during ultrasonography (USG); - Sufficient vessels which fulfilled criteria of sufficient vessels during USG examination; - Varicose veins. The study group consisted of 31 patients (23 females and 8 males) and the average age was 49.9 +/- 12.5. These patients were diagnosed with the 2nd and 3rd degree of CVD according to CEAP and they underwent surgery at II Department of General Surgery UJ CM, Poland (November, 2007-March 2008). Concentration of trace elements was determined by Proton Induced X-ray Emission (PIXE) method. Activity of superoxide dismutase was determined according to method reported by Spitz and Oberley.

RESULTS

Concentration of Zn and Cu ions was significantly higher in varicose veins in the area of insufficient valves compared to sufficient vessels. Activity of superoxide dismutase both in homogenates of varicose veins and insufficient veins was significantly higher than in homogenates of sufficient veins.

CONCLUSIONS

Clinical changes occurring during CVD were linearly dependant on SOD activity and concentration of Zn and Cu ions, which suggested the participation of free radicals in CVD

[The value of regulated upon activation normal T cell expressed and secreted in the pathogenesis of varicose ulcer of lower limbs]

OBJECTIVE

To study the effectiveness of RANTES in the pathogenesis of venous ulceration.

METHODS

40 Chronic venous insufficiency (CVI) individuals were enrolled in the study and separated into the ulceration group (n=20) and non-ulceration group (n=20), according to CVI with or without ulceration, 10 healthy individuals were enrolled as control group. The expression of RANTES mRNA was analyzed by reverse transcription-polymerase chain reaction (RT-PCR) in blood. Immunohistochemical staining of RANTES were carried in normal skin, in the tissue at the brim of ulceration and in the tissue of cured or curing ulceration.

RESULTS

In ulceration group, the expression of RANTES mRNA in blood increased obviously. Compared with the other two groups, they were significant different (P < 0.05). The difference was also significance in the other two groups (P < 0.05). The average number of RANTES positive expression in normal skin is 28 +/- 13, in the tissue at the brim of ulceration is 107 +/- 44, and in the tissue of cured or curing ulceration is 35 +/- 20. There are significant difference between normal skin and the tissue at the brim of ulceration (P < 0.05). The average number of RANTES positive expression in the tissue of cured or curing ulceration is lower than that's in the tissue at the brim of ulceration.

CONCLUSION

The high expression of RANTES may be one of the important mechanisms of varicose ulcer.

Downregulation of desmuslin in primary vein incompetence

OBJECTIVE

Primary vein incompetence is one of the most common diseases of the peripheral veins, but its pathogenesis is unknown. These veins present obvious congenital defects, and examination of gene expression profiles of the incompetent vein specimens may provide important clues. The aim of this study was to screen for genes affecting the primary vein incompetence phenotype and test the differential expression of certain genes.

METHODS

We compared gene expression profiles of valvular areas from incompetent and normal great saphenous veins at the saphenofemoral junctions by fluorescent differential display reverse-transcription polymerase chain reaction (FDD RT-PCR). Differentially expressed complimentary DNAs (cDNAs) were confirmed by Northern blotting and semi-quantitative RT-PCR. Similarity of the cDNAs sequences to GenBank sequences was determined. Gene expression status was then determined by Western blot analysis and immunohistochemical techniques.

RESULTS

There were >30 differentially expressed cDNA bands. Sequence analysis revealed that a cDNA fragment obviously downregulated in incompetent great saphenous vein was a portion of the messenger RNA (mRNA) encoding desmuslin, a newly discovered intermittent filament protein. Northern blotting and semi-quantitative RT-PCR analysis revealed a similar mRNA expression profile of the desmuslin gene in other samples. Western blotting and immunohistochemical techniques localized the desmuslin protein mainly in the cytoplasm of venous smooth muscle cells. The amount of desmuslin was greatly decreased in the smooth muscle cells of incompetent veins.

CONCLUSIONS

The expression of many genes is altered in primary vein incompetence. Up- or downregulation of these genes may be involved in the pathogenesis of this disease. Desmuslin expression is downregulated in the abnormal veins. Its effect on the integrity of smooth muscle cells might be related to malformation of the vein wall. Further studies are needed to investigate other differentially expressed cDNAs and the exact role of desmuslin in this disease.

CLINICAL RELEVANCE

Primary vein incompetence is a frequent and refractory disease of the peripheral veins. Exploring its pathogenesis may enhance our comprehension and management of this disease. We used reliable techniques to detect disease-related genes and confirmed downregulation of desmuslin in abnormal veins. Alteration of these genes might be used as disease markers or gene therapy targets.

Tissue and Urinary Haemosiderin in Chronic Leg Ulcers

OBJECTIVE

The aim of this study was to assess the relationship between urinary and tissue haemosiderin in chronic leg ulcers, and its value as a diagnostic test for venous ulceration.

METHODS

45 patients with chronic leg ulcers were recruited to the study (24 venous, 6 ischaemic, 6 lymphoedematous, 5 rheumatoid and 4 sickle cell). Punch biopsy of the ulcer edge was taken and early morning urine samples were collected. Positive Prussian-blue urinary haemosiderin granules were measured with a haemocytometer following Perls' staining. The percentage area of histological section staining positively with Perls' was measured using image analysis.

RESULTS

84 urine samples and 46 ulcer biopsies were collected. Urinary haemosiderin was present in 92% of venous ulcer patients, but was absent in the ischaemic ulcer patients (p<0.0001). Significantly more urinary haemosiderin granules were detected in venous ulcer patients compared with patients who had lymphoedema (p<0.05). Tissue haemosiderin was detected in all ulcer types investigated. No correlation was found between the amounts of haemosiderin deposited in the tissue and the amount found in urine (r(2)=0.06).

CONCLUSIONS

Haemosiderin is present in the urine of most patients with venous ulcers but not in ischaemia ulcers.

A descriptive study of skin temperature, tissue perfusion, and tissue oxygen in patients with chronic venous disease

Chronic inflammation and microcirculatory disturbances of the skin have been implicated as causative factors of complications associated with chronic venous disease (CVD). The purpose of this study is to describe the mean differences between and correlations among three measures of microcirculation: skin temperature (Tsk), tissue perfusion/blood flow (BF), and tissue oxygen (tcPO(2)) of CVD-inflamed skin compared to normal controls. In a convenience sample of 55 patients with CVD (n = 31) and without CVD (n = 24), Tsk was measured with an infrared thermometer, BF with a laser Doppler flowmeter, and tcPO( 2) with a transcutaneous oximeter across three measurements periods 1 week apart (Times 1, 2, and 3) at the medial aspect of both lower legs. Tsk was higher (1.2 degrees C) across all measurement periods (p < .05), BF was higher at Times 1 and 3 (p = .002 and .012, respectively), and tcPO(2) was lower at Times 1 and 3 (p = .013 and .050, respectively) in the CVD group as compared to the non-CVD group. BF and Tsk were positively correlated at Times 1 and 2 (r = .516, p < .005; r = 0.278, p = .04) but not at Time 3 (r = 0.235, p > .05). No consistently significant correlations were found between tcPO(2) and BF or tcPO(2) and Tsk (p > .05). Tsk and BF were higher in the skin of lower legs affected by CVD than in those not affected. Pathological processes in the skin produce heat detectable by an infrared thermometer. Measurement and monitoring of Tsk can augment clinical findings and guide treatment when localized inflammation is suspected. Future studies of Tsk should be directed toward the usefulness of infrared technology to develop a CVD leg ulcer prediction model.

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.

Tight junctions and compression therapy in chronic venous insufficiency

Tight junctions (TJs) provide a barrier function, inhibiting solute and water flow through the paracellular space. There had been no analysis until now as to how tight junction molecules could be involved in the pathology of patients with chronic venous insufficiency. The aim of the study was to analyse the expression pattern of TJ-molecules occludin (OCLN), claudin-1 (CLDN-1), claudin-3 (CLDN-3) and claudin-5 (CLDN-5) on mRNA and protein level in patients with edema, venous leg ulcers and healthy controls. Biopsy specimens were taken in healthy individuals and in patients before, and four weeks after compression therapy. mRNA-expression was determined by using reverse-transcriptase and polymerase chain reaction (RT-PCR) and the protein-expression was determined by Western blotting from tissue specimens. Quantification performed determining the expression for TJ-molecules displayed diminished expression for CLDN-1 (p<0.01) and CLDN-5 (p<0.01) in patients with chronic venous insufficiency in comparison with healthy controls on mRNA as well as protein level. No statistical differences were detected for OCLN and CLDN-3 between the edema group and healthy controls. There was a significantly elevated expression (p<0.01) on mRNA and protein level between the leg ulcer group and healthy controls for OCLN and CLDN-3. Densitometric evaluation revealed a more significantly elevated expression (p<0.01) for CLDN-1 and CLDN-5 on mRNA and protein level after four weeks of compression therapy in comparison with prior to treatment for the edema as well as the leg ulcer group. Compression therapy tightens the paracellular barrier via elevated expression of specific TJs and prevents thereby the progression of chronic venous insufficiency due to inhibited permeability of fluid into the perivascular tissue.

[Hemosiderin and siderophages in inguinal lymph nodes in chronic venous insufficiency of the legs]

Inguinal lymph nodes of patients with venous insufficiency of the lower extremities were studied by light microscopy. Presence of erythrocytes was found in all structural parts of these organs. In cortical region and paracortical zone siderophages with hemosiderin were observed. The origin of hemosiderin is discussed.

Evaluation of microcirculation in elderly patients with venous trophic ulcers

Altogether 112 patients over 50 years of age suffering from varicosity and chronic trophic ulcers of the distal limb segments were examined. The work was based on an analysis of the microcirculatory flow in lower limb tissues (laser Doppler flowmetry, BLF 21 system, Transonic Systems Inc., USA) and on the evaluation of tissue metabolism by measuring partial oxygen and carbon dioxide tension (percutaneous polarography; TCM-3 system, Radiometry Company, Denmark). The postischemic and orthostatic tests were used to assess the functional microcirculatory reserve. The data obtained indicate local tissue hypoxia in elderly patients with venous trophic ulcers associated with an increase of the basal flow only in the lower third of the leg. Venous trophic ulcers are marked by a significant reduction of partial oxygen tension in the tissues adjacent to the area of trophic ulcers to 4.3+/-0.5 mm Hg on the average in the presence of the low functional microcirculatory reserve. Local tissue hypoxia in the area of trophic ulcers, which develops despite an increase of blood inflow to the microcirculatory bed evidences inhibition of tissue flow and activation of the arterio-venular bypasses. The results obtained in the course of the study allow to optimize the treatment policy in elderly patients suffering from venous trophic ulcers. In addition to the measures lowering venous hypertension, the treatment should include correction of microcirculatory disorders, which is to be carried out in the pre- and postoperative periods.

Hypertension-induced venous valve remodeling

INTRODUCTION

In human beings, chronic venous insufficiency is linked to venous hypertension. This in turn is associated with venous valve incompetence. This study was designed to test the hypothesis that venous hypertension serves to initiate a process that results in the venous valve and venous wall damage observed in venous insufficiency. Material and methods Acute venous hypertension was produced by creation of an arteriovenous (AV) fistula between the femoral artery and vein in Wistar rats. At specified intervals pressure in the veins was recorded. The proximal valve containing saphenous vein was exposed, and reflux was measured from reverse blood flow through the first proximal valve. The vein was excised, valve parameters were measured, a portion was taken for morphologic investigation, and the remaining specimen was frozen in liquid nitrogen for investigation of leukocyte infiltration, expression of adhesion molecules, matrix metalloproteinase (MMP) levels, and apoptotic markers. Contralateral nonpressurized saphenous veins were used as control specimens.

RESULTS

The saphenous and femoral veins were immediately distended by pulsatile blood flow from the arterial system. Pressure was significantly increased from 11 +/- 2 mm Hg to 94 +/- 9 mm Hg. At 2 days no reflux was detected in the saphenous veins. At 1 week, one of four rats exhibited reflux; at 2 weeks, two of four rats had reflux; and at 3 weeks, three of four rats showed reflux. Contralateral saphenous veins were uniformly competent. Compared with control specimens, the veins were dilated; leaflet length and leaflet width were significantly reduced. Granulocytes, monocytes, and macrophages were identified in all regions of the vein wall, and the number was increased by the presence of the AV fistula. The number of T-lymphocytes was increased, and B-lymphocytes were present. P-selectin was upregulated in the saphenous vein walls, as was intercellular adhesion molecules. MMP-2 and MMP-9 expression in the veins was not enhanced. In the nuclear factor kappabeta family, Ikappabeta was not increased in any hypertensive veins. The number of apoptotic cells in the vein wall was increased in the presence of the AV fistula.

CONCLUSION

This study indicates that acute venous hypertension is accompanied by significant venous distention and some valve damage as early as 3 weeks after fistula creation. There is development of inflammatory markers, with leukocyte infiltration and increased adhesion molecule expression. We could not detect significant enhancement of MMP levels or nuclear transcription factors. It is uncertain whether this lack of evidence may be partially due to enhanced apoptosis in venous valves and vein walls. A detailed definition of the inflammatory reaction produced by venous hypertension should be the subject of further study. Clinical relevance Saphenous vein valves when observed at the time of vein stripping show deformities of shortening, scarring, and tearing. The current model of induced venous hypertension demonstrates early venous valve changes similar to those observed in human beings and links them to a venous hypertension-induced inflammatory reaction. Thus the model could be useful in pharmacologic testing to prevent or treat venous insufficiency and for defining the fundamental mechanisms that cause varicose veins.

Long saphenous vein stripping reduces local level of reactive oxygen metabolites in patients with varicose disease of the lower limbs

Long saphenous vein (LSV) stripping is the most common surgical procedure in patients affected by varicose disease of the lower limbs. Reactive oxygen metabolites (ROM) generation plays a crucial role in chronic venous insufficiency (CVI). The aim of this study was to investigate whether ROM generation is increased in patients affected by varicose disease versus healthy controls and whether LSV stripping has a positive effect on the local production of ROM. The local production of ROM was assessed measuring hydroperoxides in the blood collected from the leg of 30 patients consecutively undergoing LSV stripping and 30 controls. In both the patient group and the control group, the test was repeated 30 days later. We found that ROM levels before surgery are higher in varicose vein patients than in controls ( p <.0001) and that ROM are significantly reduced 30 days after LSV stripping ( p <.0001). At that time point, no significant differences between patients and controls was found. We also found that sex and age do not affect ROM concentration in patients and controls, either before or after surgery. In conclusion, our data indicate that CVI is characterized by significant oxidative stress and that LSV stripping is able to normalize local production of ROM in patients with varicose disease of the lower limbs. We suggest that measurement of ROM might be useful to test the positive effects of LSV stripping in these patients.

Single copy of variant CYP2A6 alleles does not confer susceptibility to liver dysfunction in patients treated with coumarin

OBJECTIVE

Coumarin, used in the treatment of chronic venous diseases, is mainly metabolized to non-toxic 7-hydroxy-coumarin by CYP2A6. At least, 3 variant alleles, CYP2A6*2, CYP2A6*3 and CYP2A6*4A, have been shown to encode catalytically defective proteins. Sporadic elevation of liver enzymes has been reported on the chronic administration ofcoumarin. We sought to determine if susceptibility to coumarin-associated liver dysfunction is genetically determined by polymorphism in CYP2A6 and impairment of the 7-hydroxylation ofcoumarin. Additionally, we were interested in the effect of polymorphism on smoking because of the predominant role of CYP2A6 in the metabolism of nicotine.

METHODS

The investigation was performed prospectively within a randomized double-blind clinical trial of the coumarin-containing drug SB-LOT (90 mg coumarin + 540 mg troxerutin/d) vs. placebo in 231 German patients with chronic venous insufficiency. Monitoring of the hepatic status involved regular measurements of liver function during the 16-week treatment. Genotyping of CYP2A6 was carried out by means of PCR and confirmed by DNA sequencing analysis.

RESULTS

The allelic frequencies of the variant CYP2A6*2 and CYP2A6*3 alleles were 0.023 and 0.014, respectively. There was no significant difference in the incidence of liver dysfunction between heterozygotes with CYP2A6*2, CYP2A6*3 and wild-type homozygotes. CYP2A6 polymorphism had no significant effect on smoking behavior.

CONCLUSION

No evidence was obtained that the studied polymorphism in CYP2A6 is a determinant of the coumarin-associated liver dysfunction.

Inflammatory mechanisms involving neutrophils in chronic venous insufficiency of lower limbs

BACKGROUND

It is supposed that an inflammatory reaction is one of the major factors responsible for the chronic venous insufficiency (CVI) of lower limbs which cause leg ulcers.

OBJECTIVES

The main objective of the present study was to determine the differences in the levels of typical inflammatory mediators and markers produced by neutrophils of patients with CVI and normal control subjects.

SUBJECTS AND METHODS

26 patients with CVI and 39 clinically healthy subjects were included in the study. In peripheral neutrophils of both groups the production of superoxide, total reactive oxygen intermediates and activities of lysosomal enzymes were measured together with the expression of 8 adhesion molecules.

RESULTS

Increased formation of superoxide by patient neutrophils and activities of elastase in both neutrophils and serum of patients were demonstrated. On the contrary, activities of myeloperoxidase and beta-D-glucuronidase were decreased in patient neutrophils. Comparing to control group adhesion molecules CD11b, CD18, CD31, CD49d, CD54 and CD62L were increased on the surface of patient neutrophils whereas no differences were observed in the expression of CD11a abd CD15.

CONCLUSION

The neutrophils of patients with CVI are primed and/or activated because they are able to release higher amount of superoxide, lysosomal enzymes and express elevated number of adhesion molecules. It may serve as one of the important evidences of an inflammatory mechanism involved in the pathogenesis of chronic venous insufficiency. (Tab. 3, Ref. 27.)

Role of matrix metalloproteinases 1, 2, and 9 and tissue inhibitor of matrix metalloproteinase-1 in chronic venous insufficiency

PURPOSE

Increased transforming growth factor-beta(1) (TGF-beta(1)) activity is associated with chronic venous insufficiency (CVI) disease progression and dermal skin pathology. Because TGF-beta(1) stimulates collagen synthesis and alters the levels of matrix metalloproteinases (MMPs) and their inhibitors (TIMPs), we investigated the hypothesis that increased TGF-beta(1) activity is associated with differences in messenger RNA and protein levels of MMPs and TIMP-1 in patients with CVI.

METHODS

One hundred ten biopsies of the lower calf and lower thigh in 73 patients were snap frozen in liquid nitrogen and stratified into six groups according to the clinical etiologic anatomic distribution pathophysiology disease classification. One set of lower-calf and lower-thigh biopsies were analyzed for MMP-1 and TIMP-1 gene expression with quantitative reverse transcription and competitive polymerase chain reaction. A second set of biopsies was analyzed for the active and latent forms of MMP-1, MMP-2, and MMP-9 as well as for TIMP-1 by western blotting, gelatin zymography, and tissue localization by immunohistochemistry (IHC).

RESULTS

Compared with the control, MMP-1 messenger RNA was increased in class-4 and class-6 patients (P < or =.01), whereas TIMP-1 was increased in class-6 patients only (P < or =.05). However, there were no differences in total protein between MMP-1 and TIMP-1. Active MMP-2 protein increased in class-4 and class-5 patients compared with active MMP-1 and TIMP-1 (P < or =.01). Western blotting did not identify the active component of MMP-9. Similarly, only the latent form of MMP-9 was observed by gelatin zymography, whereas both the latent and active forms of MMP-2 were observed. IHC demonstrated MMP-1 and MMP-2 in dermal fibroblasts and in perivascular leukocytes. TIMP-1 was observed in basal-layer keratinocytes of the epidermis only. MMP-9 was not detected by IHC.

CONCLUSION

MMP synthesis is regulated at both the transcriptional and post-transcriptional levels in CVI. Our data suggest that post-translational modifications are key to functional regulation. Dermal fibroblasts and migrating leukocytes are probable cellular sources of MMPs. Increased active MMP-2 levels in class-4 and class-5 patients indicate tissue remodeling caused by pre-ulcer and postulcer environmental stimuli. These data suggest that alterations in MMP-2 activity, in conjunction with TGF-beta(1)-mediated events, cause an imbalance in tissue remodeling leading to a pro-ulcer-forming environment.

Regulation of adhesion molecules: a new target for the treatment of chronic venous insufficiency

As more insight into the mechanisms leading to chronic venous insufficiency (CVI) is gained, novel targets for drug treatment of the disease, or of its complications, become available. Studies using chemical entities capable of inhibiting leukocyte adhesion in postcapillary venules have led to the discovery of selective inhibitors of cell adhesion mechanisms. The aim of the current review is to describe the pharmacology, biochemistry, and molecular biology studies performed with some new inhibitors of adhesion molecule expression. Compounds such as hydroxy triallyl farnisine (S 17834) may offer new and efficient treatment of the microcirculatory complications that accompany chronic venous disease.

Could gut-liver function derangements cause chronic venous insufficiency?

Upregulation of adhesion molecules and neutrophil infiltration of venous valve cusps may be risk factors for chronic venous insufficiency. But studies that focus on the target organ (vein) fail to consider the influence of systemic inflammation on WBC behavior in the microcirculation. This study probes the gut-liver axis as a potential source of gut-derived oxidative stress and free radical production leading to white blood cell activation in chronic venous insufficiency. Venous hemodynamics (ambulatory venous pressure, air plethysmography, duplex) and gut-derived oxidative stress markers were studied in nine patients with chronic venous insufficiency (group I) and nine age- and sex-matched control subjects with no venous disease (group II). Group I had healed venous ulcers (class 5, CEAP) but near-normal ambulatory venous pressure, to eliminate high ambulatory venous pressure as a chronic venous insufficiency risk factor. Markers of gut-derived oxidative stress included: stool analysis; intestinal permeability; hepatic detoxification challenges with caffeine, salicylate, and acetaminophen; and urine lipid peroxides. Ambulatory venous pressure did not significantly differ (group I, 42.5 +/- 5.3 mm Hg; group II, 35.5 +/- 5.5 mm Hg; p = NS). Candida overgrowth in stool distinguished group I from group II (7/9 pts vs 1/9 pts, respectively; p = 0.015). Increased intestinal permeability (lactulose/mannitol ratio) was prevalent in both groups (group I 0.07 +/- 0.02, group II 0.17 +/- 0.08, p = NS; normal range, 0.01-0.03). Both groups showed similar incidence of elevated urine lipid peroxides (5/9 pts vs 6/9 pts, respectively; p = NS), yet group I exhibited underfunction of both sulfation (group I 16.8 +/- 2.9%, group II 43.3 +/- 11%, p<0.03; normal acetaminophen recovery 16-36%) and glucuronidation (group I 30.4 +/- 4.1%, group II 64.1 +/- 14.4%, p<0.04; normal acetaminophen recovery 27%-56%) relative to oxidative stress, perhaps an indicator of diminished antioxidant capacity in patients with chronic venous insufficiency. Gut dysbiosis (as indicated by stool yeast) and hepatic detoxification challenge pathway exhaustion may lead to subclinical, systemic inflammation and peripheral white blood cell adhesion in chronic venous insufficiency. Further exploration of the relationship between oxidative stress and venous disease is needed.

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.

Effect of oral micronized purified flavonoid fraction treatment on leukocyte adhesion molecule expression in patients with chronic venous disease: a pilot study

PURPOSE

The purpose of this study was to determine the effects of a micronized purified flavonoid fraction treatment on surface expression of leukocyte adhesion molecules in chronic venous disease (CVD).

METHODS

Twenty patients with chronic venous disease were assessed with the use of clinical and Duplex scanning criteria. Consenting patients were treated for 60 days with a micronized purified flavonoid fraction treatment (500 mg twice daily). Blood was collected from a foot vein immediately before the start of treatment and within 1 week after the treatment was stopped. Neutrophil and monocyte surface adhesion molecule expression was determined by flow cytometry using the monoclonal antibodies to CD11b and CD62L.

RESULTS

Neutrophil CD11b (248:212), monocyte CD11B (204:190), neutrophil CD62L (130:97 [P =.002]), and monocyte CD62L (170:121 [P =.03]) were determined, respectively, before and after treatment. All values are arbitrary units and represent median values.

CONCLUSION

Micronized purified flavonoid fraction treatment for 60 days seems to decrease the surface expression of CD62L by neutrophils and by monocytes. The clinical significance of this finding needs to be explored further. It is feasible to use changes in the levels of these molecules as a marker for response to therapy in chronic venous disease.

Local oxygen content in the skin is increased in chronic venous incompetence

In skin lesions of chronic venous incompetence (CVI) transcutaneous oxygen pressure (tcpO(2)) at the ankle is often reduced. However, in some CVI patients the tcpO(2) during suprasystolic occlusion remains significantly higher than in healthy subjects. The aim of the present study was to investigate which kind of CVI patients develop this phenomenon and whether the higher tcpO(2) during occlusion is caused by a smaller oxygen consumption of the skin or by an increased local oxygen content. The oxygen consumption of the skin was measured by the pO(2) decrease (DeltatcpO(2)/Deltat) after stopping the arterial oxygen supply when the hemoglobin was saturated by oxygen inhalation, i.e., at tcpO(2) values above 120-130 mmHg. By multiplying the tcpO(2) with the mean oxygen solubility coefficient of the skin the content of physically dissolved oxygen is obtained. The decrease of tcpO(2) in the 55- to 45-mmHg range indicates the consumption of oxygen physically dissolved and chemically bound to hemoglobin. It gave a parameter for estimating the local hemoglobin content of the skin. These values and the minimal tcpO(2) after a 5-min arterial occlusion were measured in 14 healthy subjects, in 13 patients with varicose veins, but no skin lesions, in 10 patients with CVI lesions like white atrophy and lipodermatosclerosis and in 16 CVI patients with open venous ulcers. During suprasystolic occlusion tcpO(2) at the ankle remained significantly higher in CVI patients with skin lesions than in the healthy control subjects (25.6 +/- 18.9 versus 8.0 +/- 7.0 mmHg). The steepness of the tcpO(2) decrease caused by cutaneous oxygen consumption in healthy subjects was not significantly different from the CVI patients. In contrast, the decrease of tcpO(2) at the ankle between 55 and 45 mmHg was 1.9 +/- 2.0 mmHg/s in the control group and 0.7 +/- 0.5 mmHg/s in the group with open venous ulcers. These results indicate a higher hemoglobin content in the skin of the CVI patients than in healthy subjects. Obviously, the hemoglobin bound oxygen content in the skin of CVI patients is increased. Thus, a lack of oxygen is unlikely to be the primary reason for the development of skin lesions in CVI.

The effect of passage number on fibroblast cellular senescence in patients with chronic venous insufficiency with and without ulcer

BACKGROUND

Fibroblasts (fb) cultured from venous ulcer patients and patients with venous reflux disease without ulcer demonstrate characteristics of cellular senescence, such as increased fibronectin level and senescence-associated beta-galactosidase (SA beta-gal) positive cells. Cellular senescence is an in vitro event characterized by the progressive loss of proliferative capacity with increased passage number, and has been associated with impaired healing in vivo. This report examines progressive stages of cellular senescence in fb from the distal area (du-fb) and proximal fb (pu-fb) of patients with venous ulcer, as well as in distal fb (dr-fb) and proximal fb (pr-fb) from patients with venous reflux without ulcer, by comparing the population doubling time (T) and percent SA beta-gal expression.

RESULTS

The mean value of T over 6 passages for fb in the ulcer group was 132.5 +/- 29.0 hours for pu-fb and 492.9 +/- 146.2 hours for du-fb (P = 0.0009). For fb in the reflux group the mean value of T over 5 passages was 79.3 +/- 12.8 hours for pr-fb and 94.2 +/- 16.8 hours for dr-fb (P = 0.8). Comparing ulcer and reflux fb, no difference in T was observed between pu-fb and pr-fb (P = 0.6), but a difference was noted between du-fb and dr-fb (P = 0.0004). The mean percent SA beta-gal activity for fb in the ulcer group was 11.2% +/- 3.1% for pu-fb and 63.8% +/- 8.9% for du-fb (P = 0.0001). Individual passages demonstrated significant difference (P <0.05) in SA beta-gal activity between pu-fb and du-fb at early and late passages. No difference was noted in SA beta-gal activity for fb in the reflux group or between pu-fb and pr-fb, but comparison between du-fb and dr-fb was significant (63.8% +/- 8.9% versus 7.8% +/- 2.9%; P = 0.0001).

CONCLUSIONS

The in vitro passage of du-fb and pu-fb in chronic venous ulcer patients has an effect on T and cellular senescence as measured by SA beta-gal activity. Our data further suggest that du-fb are at a more progressive stage of cellular senescence when compared with pu-fb, and more importantly with fb cultured from patients with venous reflux without ulcer. These findings are consistent with impaired wound healing of venous stasis ulcer. The accumulation of senescent fb and a more advanced stage of cellular senescence of du-fb may explain why repeated episodes of venous ulceration are resistant to conservative treatment and require more aggressive measures of therapy.

Expression of the adhesion molecules ICAM-1, VCAM-1, LFA-1 and VLA-4 in the skin is modulated in progressing stages of chronic venous insufficiency

In inflammation and wound healing, dynamic changes in cell adhesion and migration are fundamental properties of the cells involved. Disturbed interaction of leukocytes with microvascular endothelial cells has been proposed to be a central pathogenic factor in chronic venous insufficiency. This disease may therefore serve to elucidate dysregulated modulation of adhesion molecule expression in conditions of chronic inflammation and impaired wound healing. In this study, we determined how the expression of ICAM-1/VCAM-1 on endothelial cells and their ligands LFA-1/VLA-4 on leukocytes is modulated in skin of progressing stages of chronic venous insufficiency. Immunohistochemical staining of skin biopsies revealed an increase in the expression of ICAM-1 and VCAM-1 on endothelial cells in an early stage of venous disease such as stasis dermatitis. Such protein expression correlated with an increase of corresponding mRNA in skin biopsies. Expression of these CAMs on endothelial cells was accompanied by the occurrence of a marked perivascular infiltration of leukocytes, which expressed increased levels of LFA-1 and VLA-4. In progressing stages of chronic venous insufficiency, characterized by hyperpigmentation and lipodermatosclerosis, which precede skin ulceration, all these CAMs remained upregulated on endothelial cells and infiltrating leukocytes. Our findings indicate that following an initial peak expression during stasis dermatitis, vascular ICAM-1 and VCAM-1 expression is not downmodulated to baseline levels, but remains upregulated. This possibly promotes tissue damage by a perpetuated, upregulated influx of activated leukocytes, finally leading to skin ulceration.

Comparison of IL-10 levels in chronic venous insufficiency ulcers and autologous donor tissue

In previous immunohistochemical studies, chronic venous insufficiency (CVI) ulcers have been shown to display positive staining for interleukin-10 (IL-10), while other wounds (including autologous donor wound tissue) show a reduced staining level. IL-10 inhibits the synthesis of many proinflammatory cytokines, while also inhibiting antigen presentation by antigen-presenting cells. It is possible that abnormally high amounts of IL-10 in chronic wounds may be related to the failure of these wounds to progress to final wound healing. The purpose of this study was to quantify the levels of IL-10 in CVI ulcers and autologous donor tissue using Western blotting. Extracts were prepared from frozen wound tissue samples and equal amounts of protein were concentrated by immune-precipitation for Western blot analysis. Densitometric analysis was performed on nonsaturated chemilumigraphs and normalized to an IL-10 standard run on each gel. The quantity of IL-10 in CVI ulcers was found to be 490% of the quantity in autologous donor tissue. This study provides confirmatory quantitative data which supports previous immunohistochemical findings showing elevated levels of IL-10 in CVI ulcers.

Patterns of epidermal growth factor receptor, basic fibroblast growth factor and transforming growth factor-beta3 expression in skin with chronic venous insufficiency

Growth factors which act as signalling peptides through specific cell surface receptors are involved in functions such as cell proliferation, migration, and differentiation. Here, we report on alterations of the epidermal growth factor receptor (EGFR), basic fibroblast growth factor (bFGF) and transforming growth factor beta3 (TGF-beta3) expression patterns in the skin at various stages of chronic venous insufficiency (CVI). Thirty punch biopsies were taken from patients with CVI and growth factors or the growth factor receptor were detected by indirect immunofluorescence and immunoperoxidase techniques. EGFR, bFGF, and TGF-beta3 expression is strongly increased in the stroma of venous eczema and in leg ulcer skin, and to a lesser extent in the dermis of patients with lipodermatosclerosis. Venous eczema and lipodermatosclerosis epidermis show an elevated EGFR and bFGF synthesis throughout all strata. In the different CVI stages, telangiectases and reticular veins and pigmentation EGFR and bFGF staining are limited to the basal layer. We conclude that the alterations in the expression of EGFR, bFGF and TGF-beta3 precede changes in the affected skin within progressing stages of CVI. The exact mechanisms of growth factor involvement in the pathogenesis of venous ulceration remain to be resolved.

Increased expression of platelet-derived growth factor receptor alpha and beta and vascular endothelial growth factor in the skin of patients with chronic venous insufficiency

Growth factors produced by a variety of cells act as signalling peptides through specific cell surface receptor pathways. Functions such as cell proliferation, migration and differentiation have been assigned to each of them. Here, we report alterations of platelet-derived growth factor receptor alpha (PDGFR-alpha) and beta (PDGFR-beta) and vascular endothelial growth factor (VEGF) expression patterns in the progressive clinical stages of chronic venous insufficiency (CVI). A total of 30 punch biopsies were taken from patients with CVI, and VEGF and PDGFR were detected by indirect immunofluorescence and immunoperoxidase techniques. PDGFR-alpha and PDGFR-beta expression was strongly increased in endothelial cells of capillaries, pericapillary cells and connective tissue cells in the stroma of the skin of venous eczema and venous leg ulcer patients, and to a smaller extend in the dermis of those with lipodermatosclerosis. VEGF staining showed a similar expression pattern in the progressive CVI stages. However, staining of vessels in particular might simply reflect binding of VEGF, secreted by keratinocytes or fibroblasts, to its receptors. Growth factor and receptor expression in specimens from telangiectases and reticular veins, and from pigmented areas, resembled that of normal skin. We conclude that PDGFR-alpha, PDGFR-beta and VEGF play an important role in mediating inflammation and epithelial hyperproliferation in venous eczema, inducing connective tissue sclerosis in lipodermatosclerosis, and causing the reduced reepithelialization tendency in venous ulcers. We speculate that endothelial proliferation with chronic venous hypertension might be mediated by these growth factors.

Levels of the inhibitor of PMN-elastase in venous blood reflowing from chronically affected veins: the role of venous stasis

BACKGROUND

Attention has recently been paid to the cell and biochemical disorders involved in chronic venous insufficiency (CVI) and to their possible relationship to the endothelium.

METHODS

In the present study, carried out in 14 patients with CVI, we evaluated the levels of the inhibitor of elastase (I-EL) generated by polymorphonucleate cells in the blood reflowing from affected superficial veins of legs both at rest and after prolonged venous stasis (1 hour in standing position).

RESULTS

We evaluated the I-EL both as percentage of activity (baseline 82.3+/-24.5%; after stasis 100.7+/-37.8%) and as absolute values (0.67+/-0.26 U/ml; after stasis 0.79+/-0.39 U/ml). In blood samples taken after venous stasis we found a tendency toward a trapping of white blood cells and an increase of the haematocrit over baseline. The difference in the percentages of activity of I-EL was statistically significant, but only a trend was observed for the absolute values.

CONCLUSIONS

We believe that the typical haemodynamic disorders of patient with CVI increased by prolonged venous stasis can modify the function of white blood cells, which are closely linked with venous hypertension, thus playing an important role in the pathogenesis of skin ulcers.

Use of lightguide spectrophotometry to investigate the effect of postural changes on skin oxygenation in deep venous insufficiency

BACKGROUND

Postural changes play an important role in the development of venous disease. The aim of this study was to investigate skin oxygenation in patients with deep venous insufficiency.

METHODS

Haemoglobin oxygen saturation (SO2) was measured with macro- and micro-lightguide spectrophotometry in clinically normal skin at the gaiter area with the leg in the supine position, raised to 45 degrees and on standing. Similarly, transcutaneous oxygen tension (PtcO2) and laser Dopper flux (LDF) values were obtained. SO2 was also measured after heating the skin to 44 degrees C in the supine and standing positions.

RESULTS

SO2 and PtcO2 decreased on leg raising (P < 0.05 and P < 0.01 respectively). SO2 fell on standing (P < 0.05) while PtcO2 rose (P < 0.05). On heating the skin, SO2 increased (P < 0.05) on standing. LDF fell on standing (P < 0.005) but increased on leg raising (P < 0.05).

CONCLUSION

Lightguide spectrophotometry showed a profound decrease in skin oxygenation on standing and leg raising; PtcO2 measurements may miss the role of vasoconstriction with postural changes.

Clinical histochemical and immunohistochemical investigation of the capillary basal membrane in chronic venous insufficiency

Present investigations regarding the pathogenesis of chronic venous insufficiency (CVI) are focusing on microvascular changes. The aim of our investigation was to examine the correlation between the thickness of pericapillary type IV collagen depositions, basal membrane alterations and transcutaneous oxygen tension (TcPO2) in CVI-patients. Histochemical and immunohistochemical investigation of the capillary basal membrane was performed on 15 biopsies from normal controls, as well as 30 patients with CVI stage I and III (classification by Widmer & Stähelin). In all subjects TcPO2 was measured just prior to biopsy procedures in exactly the same area where the specimen was subsequently excised. The microscopically measured thickness of the collagen IV layer and the basal membrane was increased significantly in patients with CVI. Specimens from normal controls showed a collagen IV layer thinner than 0.1 micron. Patients with CVI stage III revealed strong collagen IV depositions between 0.2 and 0.3 microns. Comparison between TcPO2 and histological findings in the measured ares showed oxygen pressure varying from 62 mmHg (SEM 4.94 mmHg) in normal controls, down to 13 mmHg (SEM 3.39 mmHg) in patients with thick collagen IV layers. Besides an increased collagen IV layer, microvascular thrombosis and a thickened basal membrane have to be considered for impaired capillary perfusion.

Differential release of endothelin in myocutaneous island flaps in response to gradually insetting venous stasis or arterial ischemia

Endothelin (ET) provokes strong and sustained contraction in preparations of isolated vascular smooth muscle, and the production of ET is thought to increase secondary to increased wall shear stress and hypoxia. The release of ET and blood flow distribution between arteriovenous shunts and capillaries were studied in autoperfused myocutaneous pig island flaps during graded arterial or venous blood flow reduction (N = 12). A group comprising four flaps was not exposed to blood flow reduction and served as controls. Total flap blood flow (venous outflow [VO]) was reduced in 1-hour periods to 50%, 25%, and 0%. Downregulation of VO caused a lower capillary blood flow (CBF) at 25% (P < .05) and at 50% (P < .05) in flaps exposed to venous stasis as compared with flaps with arterial ischemia. The reduction in blood flow was paralleled by decreasing oxygen consumption, although flaps with venous stasis had lower oxygen consumption than flaps exposed to arterial ischemia (P < .05). ET was found to be released from these island flaps before blood flow was reduced. Gradual arterial clamping caused a statistically significant (P < .05) decrease in the release of ET from 8.7 +/- 1.3 fmol/min before ischemia to 4.1 +/- 1.7 at 50% blood flow and 4.1 +/- 1.0 at 25% blood flow. In contrast, the release of ET with venous stasis remained unchanged at a level of 7.5 +/- 1.6 fmol/min before blood flow reduction, 7.3 +/- 0.7 at 50% blood flow, and 8.5 +/- 1.6 at 25% blood flow. These data suggest a relationship between CBF, intravascular pressure, and ET production.(ABSTRACT TRUNCATED AT 250 WORDS)

[Microcirculation and rheology]

Microvessels, especially in the skin and muscles are organized in functional units. These units are controlled by the adrenergic system and hormones but also have autonomous metabolic and myogenic regulatory systems independent of vasomotion. Microcirculatory blood flow is affected by special rheologic properties: a low arteriolar haematocrit rises to the systemic level in the venules. The flow rate in the venules is low, and together with the raised haematocrit, explains the microvenular sensitivity to hyperviscosity. Capillarovenular microangiopathy, recently described by standard and fluorescent capillaroscopy, develops during chronic venous insufficiency. The capillary loops appear dilated and knotted together with fibrous deposits and pericapillary oedema. Venous hyperpressure is the cause of this microangiopathy. Together these phenomena disrupt normal haemodynamics and physiology of the microcirculatory unit: baseline hyperhaemia, lowered vasomotor and vasomotion reactivity, development of rheologic disorders (haemoconcentration, hyperfibrinogenaemia, erythrocyte agregation) and decreased fibrinolysis. Modifications in the transcapillary exchange is related to hypoxia and is aggravated by depressed lymphatic drainage. The main consequence is oedema. Inflammation, a characteristic of these microangiopathies could occur when the endothelium is activated by the hypoxia. The classical mediators of inflammation would activate interactions between the different cells: endothelium, granulocytes, monocytes and platelets. Several pharmacological models have been developed for the analysis of these data including exploration of the permeability and capillary resistance and rheological analysis. Objective observation of the microangiopathy with capillaroscopy, together with modern haemodynamical, biological and pharmacological methods are essential for a better understanding of microvascular disorders in chronic venous insufficiency.

[The relation between venous stasis and the occurrence of pain]

Venous stasis is a situation encountered commonly in varicose disorders. The potential implications of this decrease in oxygen levels in terms of the status of the cells of the vein were assessed. When endothelial cells are subjected to hypoxia, there is stimulation of the cells which shows itself as increased synthesis of prostaglandins and of PAF (Platelet Activating Factor). The synthesis of these typical mediators of inflammation results from activation by the calcium of phospholipase A2 which releases the arachidonic acid of phospholipids and this increase in intracellular calcium results itself from a fall in efficacy of calcium pumps due to the fall in ATP caused by hypoxia. Thus the fall in oxygen leads to the production of mediators of inflammation which activate leucocytes and result in local micro-inflammation which can be very rapidly eliminated if the circulation is restored but which can also cause irreversible damage to the vein by changes in venous tissue due to activated leucocytes which release proteases and free radicals after having penetrated the intima of the vein. These processes offer an explanation for the histological changes seen in varicose veins and the onset of localised pain during the development of such disease.

[Inflammation and subcutaneous calcification of venous origins]

There have been few descriptions up to now of calcifications in chronic venous insufficiency, other than in cases where venous insufficiency is complicated be severe trophic disorders and in particular ulcers. It was therefore felt to be of interest to assess the presence of calcifications in venous insufficiency without trophic disorders. This study was based upon 40 cases recruited in the phlebology out-patient clinic of the Notre Dame de Bon Secours Hospital. Calcifications of the lower limbs were found in 7 patients, either by palpation, routine X-rays or ultrasonography. The etiopathogenic mechanisms of this occurrence not having been elucidated, a number of hypotheses are put forward on the basis of acquired data concerning: the process of formation of ectopic calcifications, changes in subcutaneous tissue, the ultimate consequences of venous stasis and of raised venous pressure, due essentially to anoxia and inflammation. One hypothesis can thus be put forward: that of inflammation. The release of cells and mediators of inflammation, the production of free radicals, causing damage to the cells of connective tissue and to the organic framework (collagen fibres) and changes in the chemical environment could combine to result in the formation of calcifications in subcutaneous tissue. However, inflammation has not been proven to be the primary etiological factor.

Edema-preventing mechanisms in rat gingiva

The long-term effect of increased local venous pressure (Pv) on interstitial fluid pressure (Pi), colloid osmotic pressure (COPi), and fractional removal rate of 125I-labeled human serum albumin (kAlb) was studied in rat gingiva. Measurements were performed on experimental animals and sham-operated controls up to 4 days after ligation of jugular veins. On the day of ligation Pv in the facial veins rose from 2.5 +/- 0.3 (SD) to 15.8 +/- 2.8 mm Hg and stayed at about this level for 2 days before a decrease to 7.4 +/- 0.9 mm Hg on day 4. In free gingiva Pi rose from an average of 3.5 +/- 0.4 to a maximum of 6.3 +/- 0.7 mm Hg, whereas in attached gingiva the corresponding increase in Pi was from 6.0 +/- 0.7 to 11.1 +/- 2.1 mm Hg. One day after the ligation COPi in wick fluid from gingiva was reduced from the control level of 10.6 +/- 1.4 to 4.5 +/- 0.9 mm Hg. COP in plasma and COPi in subcutaneous tissue on the back were unaffected. The removal rate of 125I-labeled albumin (kAlb) from the gingiva showed a nearly threefold increase after venous ligation, from 0.073 +/- 0.01 to 0.211 +/- 0.06 h-1. It is concluded that in free and attached gingiva, both a rise in Pi and a decrease in COPi will counteract the increased filtration pressure and thus prevent edema formation during venous stasis. The fall in COPi is most likely due to increased lymph flow and not dilution, as venous stasis significantly increased kAlb without any visible increase in gingival volume.

Tissue concentrations of ofloxacin in necrotic lesions in patients with peripheral vascular disease and in diabetics

In a pilot study six patients (three diabetics with gangrenous lesions of the lower limbs, mean age 74 years, three patients with peripheral vascular disease stage IV according to Fontaine, mean age 70 years) were treated with 200 mg ofloxacin orally b.i.d. The tissue concentrations of ofloxacin in the necrotic material (1.6 to 6.4 mg/kg) were in the same range as the plasma levels (2.3 to 5.9 mg/l) or even higher. In conclusion, besides local therapy, ofloxacin seems to be effective in the systemic treatment of infected necrotic and gangrenous lesions.

[Oxygen pressure fields in ulcers of the lower leg]

Using a multi-wire surface electrode, oxygen pressure fields were determined in leg ulcers of 11 patients with chronic venous insufficiency (cvi). In three of them, cvi was combined with arterial occlusive disease. The histograms of all patients with very low PO2 values revealed microcirculatory disturbances of the ulcer tissue. The influence of leg position is reflected in the histograms. Patients with cvi showed higher PO2 values when the leg was raised in comparison with when it was in the hanging position. The patients with mixed ulcerations showed a significant increase in tissue PO2 when the leg was in the hanging position, which shows the importance of arterial perfusion pressure. After a compression bandage had been applied to the legs with cvi, the tissue oxygen pressure of the ulcers increased markedly, probably as a result of diminished blood stasis. These results can be explained either by a rarefaction of capillaries in the ulcer tissue or by fibrin diffusion barriers around the capillaries. The changes in the histograms after bandaging are thought to be caused by an improvement in venous circulation.