Structural changes in the tunica intima of varicose veins: a histopathological and ultrastructural study

Morphological restructuring of smooth muscles elements of the wallgreat saphenous vein of a person on the lower leg during the development of varicose transformation

Introduction. Further study of the structural restructuring of the wall of the great saphenous vein throughout a person’s life with the development of chronic venous diseases is an urgent task of phlebology.

The purpose of the study. Research of the morphological restructuring of smooth muscleselements of the human great saphenous vein wall on the calf in norm, ectasia and development of varicose transformation.

Materials and methods. The study of morphological restructuring of the great saphenous vein wall on the calf was carried out in 3 comparison groups by light microscopy. In 1th group, the structure of the GSV wall was studied on autopsy material of people who died from various causes at the age of 5 to 80 years. In the 2nd and 3rd groups, fragments of GSV in the calf were taken by biopsy during the execution of the operations for varicose veins. All patients underwent ultrasound mapping before surgery to determine the presence and degree of ectasia, varicose transformation and retrograde blood flow. For histological analysis in the groups, 140 GSV fragments were removed in 1-group, 165 BPV fragments in 2-group, and 250 GSV fragments in 3-group.

Results. The general morphological analysis of histological preparations made it possible to visually identify various variants of changes in smooth muscleselements inherent in the inner, middle and outer shells of the GSV wall. The selected variants of reconstruction of the smooth muscleselements were combined into 10 morphological types.

Conclusion. Age-related morphological changes in the smooth muscleselements in the GSV wall on the calf, over the course of a person’s life, do not have the same character as changes occurring in its wall during the development of its ectasia and varicose transformation.

Quantification and Statistical Analysis Methods for Vessel Wall Components from Stained Images with Masson's Trichrome

PURPOSE

To develop a digital image processing method to quantify structural components (smooth muscle fibers and extracellular matrix) in the vessel wall stained with Masson's trichrome, and a statistical method suitable for small sample sizes to analyze the results previously obtained.

METHODS

The quantification method comprises two stages. The pre-processing stage improves tissue image appearance and the vessel wall area is delimited. In the feature extraction stage, the vessel wall components are segmented by grouping pixels with a similar color. The area of each component is calculated by normalizing the number of pixels of each group by the vessel wall area. Statistical analyses are implemented by permutation tests, based on resampling without replacement from the set of the observed data to obtain a sampling distribution of an estimator. The implementation can be parallelized on a multicore machine to reduce execution time.

RESULTS

The methods have been tested on 48 vessel wall samples of the internal saphenous vein stained with Masson's trichrome. The results show that the segmented areas are consistent with the perception of a team of doctors and demonstrate good correlation between the expert judgments and the measured parameters for evaluating vessel wall changes.

CONCLUSION

The proposed methodology offers a powerful tool to quantify some components of the vessel wall. It is more objective, sensitive and accurate than the biochemical and qualitative methods traditionally used. The permutation tests are suitable statistical techniques to analyze the numerical measurements obtained when the underlying assumptions of the other statistical techniques are not met.

Association between the hypomethylation of osteopontin and integrin β3 promoters and vascular smooth muscle cell phenotype switching in great saphenous varicose veins

Lower extremity varicose veins are a common condition in vascular surgery and proliferation of vascular smooth muscle cells (VSMCs) in the intima is a significant pathological feature of varicosity. However, the pathogenesis of varicose veins is not fully understood. Osteopontin (OPN) could promote the migration and adhesion of VSMCs through the cell surface receptor integrin β3 and the cooperation of OPN and integrin β3 is involved in many vascular diseases. However, the role of OPN and integrin β3 in varicosity remains unclear. In the current study, we found that the methylation levels in the promoter regions of OPN and integrin β3 genes in the VSMCs of varicose veins are reduced and the protein expression of OPN and integrin β3 are increased, compared with normal veins. Furthermore, it was observed that VSMCs in the neointima of varicose veins were transformed into the synthetic phenotype. Collectively, hypomethylation of the promoter regions for OPN and integrin β3 genes may increase the expression of these genes in varicosity, which is closely related to VSMC phenotype switching. Hypomethylation of the promoter regions for OPN and integrin β3 genes may be a key factor in the pathogenesis of varicosity.

Systemic connective tissue abnormalities in patients with saccular intracranial aneurysms

OBJECTIVES

Our purpose was to identify the incidence and significance of markers of systemic connective tissue abnormalities (CTA) in patients with saccular intracranial aneurysms (SIA).

MATERIALS AND METHODS

This prospective case-control study included 199 consecutive patients with SIA (103 women and 96 men, mean age - 43.2 years) and 194 control patients - blood donors (108 - men, 86 - women, mean age - 38.4 years). Aneurysms were verified by conventional cerebral angiography. All patients were examined by the first author using a specially designed questionnaire and a standardized physical examination with special emphasis on systemic CTA.

RESULTS

Twelve markers of systemic CTA were significantly higher in patients with SIA than in controls: visible vessels on face and chest (59.8%), scoliosis (44.7%), varicose veins in legs (39.7%), flatfoot (34.6%), hyperextensibility of the skin (33.6%), spontaneous epistaxis (25.6%), easy bruising (20.6%), abdominal hernia (13.6%), periodontal disease (10.5%), chest deformations (7.5%), abdominal striae (3.5%), joint hypermobility (2.5%). A blinded validation study in a subset of 43 patients showed similar results. Among patients with SIA, 125 of 199 patients (62.8%) had at least three markers of systemic CTA compared with 23 (11.8%) of the controls (P < 0.0001, OR = 12.5, 95% CI 7.45-21.1). The mean number of markers of systemic CTA in patients with SIA was 3.07 and 1.17 in controls.

CONCLUSION

Patients with SIA have multiple markers of systemic connective tissue abnormalities. Systemic weakness of connective tissue represents a risk factor for development of SIA. Identification of these markers may help in detection of high-risk patients.

Morphological characteristics of the walls of thrombophlebitic saphenous vein

Introduction: To investigate the morphological changes in the walls of thrombophlebitic saphenous veins.

Methods: Fifty-four specimens were made into slices for haematoxylin and eosin and Masson trichrome staining; ultrathin slices were also created. Slices were observed under light microscopy and electron microscopy.

Results: Under light microscopy, the tunica intima of venous wall in the thrombophlebitic saphenous veins group was obviously thickened and incomplete; intravascular papillary endothelial hyperplasia was observed. Hyperplasia of collagenous fibres in the tunica media was observed. Elastic fibres in the tunica externa became fewer, whereas nourishing vessels were significantly increased in number. Infiltration of many inflammatory cells was observed. Under electron microscopy, Auer bodies with high electron density and round granules could be seen in endothelial cells in the thrombophlebitic saphenous veins group. Smooth muscle cells had an irregular karyotype, with blurred cristae in some mitochondria. Myofilaments basically disappeared.

Conclusion: Thrombus formation might aggravate re-modelling of the walls of varicose veins.

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.

Alterations in Purinoceptor Expression in Human Long Saphenous Vein during Varicose Disease

OBJECTIVES

Varicose veins are dilated tortuous veins of varying tone. Purinergic signalling is important in the control of tone and in mediating trophic changes in blood vessels. The expression of P2 receptors in control and varicose veins will be examined.

METHODS

Purinergic signalling in circular and longitudinal smooth muscle of the human long saphenous vein was studied in control and varicose tissues using immunohistochemistry, organ bath pharmacology and electron microscopy.

RESULTS

P2X1, P2Y1, P2Y2, P2Y4 and P2Y6 receptors were present on circular and longitudinal smooth muscle. Purine-mediated circular and longitudinal muscle contractions were weaker in varicose veins. Electron microscopy and immunohistochemistry findings support the view that smooth muscle cells change from the contractile to synthetic phenotype in varicose veins, associated with an upregulation of P2Y1 and P2Y2 receptors and a down regulation of P2X1 receptors.

CONCLUSIONS

Down regulation of P2X1 receptors on the smooth muscle of varicose veins is associated with loss of contractile activity. Upregulation of P2Y1 and P2Y2 receptors is associated with a shift from contractile to synthetic and/or proliferative roles. The phenotype change in smooth muscle is associated with weakening of vein walls and may be a causal factor in the development of varicose veins.

Comparison of extracellular matrix in skin and saphenous veins from patients with varicose veins: does the skin reflect venous matrix changes?

Varicose vein disease is a frequently occurring pathology with multifactorial causes and a genetic component. An intense remodelling of the varicose vein wall has been described and could be at the origin of its weakness and altered elasticity. We have described previously a dysregulation of collagen synthesis in cultured smooth muscle cells from saphenous veins and in dermal fibroblasts from the skin of patients with varicose veins, suggesting a systemic defect in their connective tissue. The present study describes comparative morphological and immunohistochemical data in both the skin and saphenous veins of eight control subjects (undergoing coronary bypass surgery) and eight patients with varicose veins. Histological staining of glycoproteins, the elastic fibre network and collagen bundles showed that the remodelling and fragmentation of elastic fibres observed in varicose veins were also present in the skin of the patients. When compared with control subjects, we observed in both the veins and skin of patients with varicose veins (i) an increase in the elastic network, as quantified by image analysis; (ii) an accumulation of collagen type I, fibrillin-1 and laminin; and (iii) an overproduction of MMP (matrix metalloproteinase)-1, MMP-2 and MMP-3, analysed by immunohistochemistry, but normal levels of other MMPs (MMP-7 and MMP-9) and their inhibitors (TIMP-1, TIMP-2 and TIMP-3). An imbalance of extracellular matrix production/degradation was thus observed in veins as well as in the skin of the patients with varicose veins and, taken together, these findings show that remodelling is present in different organs, confirming systemic alterations of connective tissues.

Overexpression of transforming growth factor-beta1 correlates with increased synthesis of nitric oxide synthase in varicose veins

INTRODUCTION

Transforming growth factor-beta 1 (TGF-beta 1 ) is known to maintain a balance between apoptosis and cellular dysfunction and therefore may have a pivotal role in vessel remodeling during pathogenesis of vascular disorders. We previously demonstrated that inducible nitric oxide synthase (iNOS) mediates signal transduction in vascular wall during the development of varicose veins. Currently, we investigated the expression and correlation of TGF-beta 1 , iNOS, monocyte/macrophage infiltration, and loss of vascular smooth muscle cells (VSMCs), in a series of normal and varicose vein specimens.

METHODS

Twenty varicose vein specimens were retrieved from 20 patients undergoing lower-extremity varicose vein excision, and 27 normal greater saphenous vein segments (controls) were obtained from 27 patients undergoing infrainguinal arterial bypass surgery. Principal risk factors (diabetes mellitus, hypertension, tobacco abuse) were also compared. Varicose vein segments were separated into tortuous and nontortuous regions based on their macroscopic and microscopic morphology. VSMC actin, CD68 + monocytes/macrophages, iNOS, and TGF-beta 1 , were examined by immunohistochemistry, immunoblotting, and real-time reverse transcriptase polymerase chain reaction.

RESULTS

According to the CEAP classification for chronic lower extremity venous disease, most of the patients were in class 2 for clinical signs of the disease (n = 11). Mean ages were 53.6 +/- 4.7 years for the varicose vein group and 56.5 +/- 4.4 years for the controls. The gender distribution was same in both groups. Immunoreactivity to TGF-beta 1 and iNOS was significantly different in the tortuous regions of the varicose veins compared with nontortuous regions (P < .01). Not only was a significantly higher expression of iNOS noted in the varicose vein group (P < .001), but a differential expression of iNOS was also observed in the tortuous and nontortuous portions of the varicose veins. Significant overexpression of TGF-beta 1 (P < .01) that correlated with overproduction of iNOS and with increased presence of CD68 + monocytes/macrophages was observed in the varicose vein walls compared with normal veins.

CONCLUSIONS

This is the first evidence of TGF-beta 1 , as well as iNOS, being differentially upregulated in nontortuous and tortuous segments of varicose veins. The increased expression of TGF-beta 1 and presence of macrophages, correlating with overproduction of iNOS, may be associated with varicosity development and deserves further study.

CLINICAL RELEVANCE

The pathogenesis of varicose veins, the most common manifestation of chronic venous disease, is debatable. Elucidation of mechanisms involved in the disease process is the first step to improved therapeutic modulations. Towards this goal, the relationship between NO production and TGF-beta 1 in the molecular pathophysiology of chronic venous disease was investigated. The data identify for the first time, an important role for TGF-b1-iNOS-monocyte/macrophage signaling in the etiology of varicosities. Furthermore, we determine if there are any significant differences within the varicose vein group itself based on regional differences, by classifying the varicose tissues into tortuous and non-tortuous segments.

Intimal changes in varicose veins: an ultrastructural study

In order to study the structural changes in the intimal layer of varicose veins, we prospectively collected a total of 23 vein specimens from both the normal proximal thigh long saphenous (LSV) in 3 young trauma patients and from the unstripped proximal LSV near the sapheno-femoral junction and the distal calf blowouts in 10 primary varicose veins patients. Paraffin sections stained with hematoxylin and eosin were examined under the light microscope while ultra-thin sections were examined under the transmission electron microscope (TEM). Compared with the normal control LSV, varicose vein sections showed increase in the diameter of the lumen, hypertrophy of the wall and elongation and invagination of the intima. Along these invaginations, endothelial cells were compressed, elongated and thinned out. The cells also showed progressive degeneration and were finally lost into the lumen, leaving only the basal lamina to form the luminal surface. This invited blood components like platelets and red blood cells to stick to the bare intima and to penetrate through the wall. This may form the basis of the clinical condition of superficial thrombophlebitis, which sometimes complicates cases of varicose veins. In conclusion, varicose veins showed increased diameter of the lumen and hypertrophy, elongation and invagination of the intima. There was marked degeneration of the endothelial cells and desquamation of the endothelial layer.

Smooth muscle changes in varicose veins: an ultrastructural study

In order to understand the pathology of varicose veins, we prospectively collected a total of 23 vein specimens both from the normal proximal thigh long saphenous vein (LSV) in 3 young trauma patients and from the unstripped proximal LSV near the sapheno-femoral junction and the distal calf blowouts in 10 primary varicose veins patients. Ultra-thin sections were examined under the transmission electron microscope (TEM). Compared with the normal control LSV, varicose vein sections showed increase in the diameter of the lumen, hypertrophy of the wall and elongation and invagination of the intima. Smooth muscle cells (SMCS) lost their normal fusiform shape and were widely separated by increased amounts of extra-cellular collagen fibers. The cells underwent marked degeneration, vacuolization and disintegration into fiber-like material and small separated fragments. SMCs were seen in the subintimal tissue and some of them were lost into tile lumen. SMCs also showed marked phagocytic activity, engulfing not only collagen and elastic fibers, but also other smooth muscle cells. Although these changes were more marked and advanced in the distal calf blowouts, they were also present in the proximal, clinically non-dilated LSV. In conclusion, SMCs of varicose veins show severe degeneration in both the distal calf blowouts and the proximal, clinically non-varicose LSV. It appears that they both form and phagocytose collagen and elastic fibers and play a major role in the pathogenesis of varicose veins.