Mechanisms of varicose vein formation: valve dysfunction and wall dilation

Glycyrrhetinic Acid Antagonizes Pressure-Induced Venous Remodeling in Mice

Development of spider veins is caused by the remodeling of veins located in the upper dermis and promoted by risk factors such as obesity or pregnancy that chronically increase venous pressure. We have repeatedly shown that the pressure-induced increase in biomechanical wall stress is sufficient to evoke the formation of enlarged corkscrew-like superficial veins in mice. Subsequent experimental approaches revealed that interference with endothelial- and/or smooth muscle cell (SMC) activation counteracts this remodeling process. Here, we investigate whether the herbal agent glycyrrhetinic acid (GA) is a suitable candidate for that purpose given its anti-proliferative as well as anti-oxidative properties. While basic abilities of cultured venous SMCs such as migration and proliferation were not influenced by GA, it inhibited proliferation but not angiogenic sprouting of human venous endothelial cells (ECs). Further analyses of biomechanically stimulated ECs revealed that GA inhibits the DNA binding capacity of the mechanosensitive transcription factor activator protein-1 (AP-1) which, however, had only a minor impact on the endothelial transcriptome. Nevertheless, by decreasing gelatinase activity in ECs or mouse veins exposed to biomechanical stress, GA diminished a crucial cellular response in the context of venous remodeling. In line with the observed inhibitory effects, local transdermal application of GA attenuated pressure-mediated enlargement of veins in the mouse auricle. In summary, our data identifies GA as an inhibitor of EC proliferation, gelatinase activity and venous remodeling. It may thus have the capacity to attenuate spider vein formation and remodeling in humans.

Plasma concentration of selected biochemical markers of endothelial dysfunction in women with various severity of chronic venous insufficiency (CVI)-A pilot study

BACKGROUND

Although the endothelial dysfunction is considered to be implicated in the pathogenesis of chronic venous insufficiency (CVI) the endothelial status in patients with venous disorders is still not fully evaluated. Therefore the aim of the study was to measure the concentration of selected markers of endothelial dysfunction: von Willebrand factor (vWf), soluble P-selectin (sP-selectin), soluble thrombomodulin (sTM) and soluble VE-cadherin (sVE-cadherin) in CVI women who constitute the most numerous group of patients suffering from venous disease.

MATERIALS AND METHODS

Forty four women with CVI were involved in the study and divided into subgroups based on CEAP classification. Concentration of vWf, sP-selectin, sTM and sVE-cadherin were measured and compared with those obtained in 25 healthy age and sex-matched women.

RESULTS

It was found that the concentration of sTM increased and sVEcadherin decreased along with disease severity in CVI women. A significant rise of sTM was observed especially in CVI women, with the highest inflammation status reflected by hsCRP or elastase concentration, and in CVI women with a high oxidative stress manifested by an increased plasma MDA. A significant fall of circulating sVE-cadherin was reported in CVI women with moderate to highest intensity of inflammation and oxidative stress. There was no change in vWF and sP-selectin concentration at any stage of CVI severity.

CONCLUSIONS

The results of the present study demonstrate the presence of endothelial dysfunction in women suffering from CVI which seems to progress with the disease severity and may be associated with inflammation and enhanced oxidative stress.

Expression of the proinflammatory marker CD34 in varicose leg veins

Objective: To study the CD34 expression in the leg veins with primary varicose veins.

Material and Methods: The study included 18 patients with lower limbs varicose veins and deep vein valves insufficiency of C3 and C4 clinical classes (CEAP). To correct blood flow phlebectomy was accompanied by posterior tibial veins resection. Using immunohistochemistry, we compared the expression of CD34 in resected posterior tibial veins specimens and vena saphena magna distal fragment.

Results: Posterior tibial veins wall in patients with lower limb varicosity and deep veins valves insufficiency vary the CD34 degree expression comparing with the control group. Total area of expression was significantly greater than in control sample. CD34 expression area was also significantly greater in vena saphena magna than in control group. CD34 expression comparison in the specimens from patients with varicose veins showed its significantly higher degree in the vena saphena magna than in tibial veins.

Conclusion: With primary varicose veins superficial and deep leg veins develop unidirectional increase of CD34 expression, that can be assumed as a pathogenetic factors of further disease progression and involvement of deep vein valves.

Variability of MMP/TIMP and TGF-β1 Receptors throughout the Clinical Progression of Chronic Venous Disease

Chronic venous disease (CVeD) is a prevalent condition with a significant socioeconomic burden, yet the pathophysiology is only just beginning to be understood. Previous studies concerning the dysregulation of matrix metalloproteinases (MMPs) and their inhibitors (tissue inhibitors of metalloproteinases (TIMPs)) within the varicose vein wall are inconsistent and disregard clinical progression. Moreover, it is highly plausible that MMP and TIMP expression/activity is affected by transforming growth factor (TGF)-β1 and its signaling receptors (TGFβRs) expression/activity in the vein wall. A case–control study was undertaken to analyze genetic and immunohistochemical differences between healthy (n = 13) and CVeD (early stages: n = 19; advanced stages: n = 12) great saphenous vein samples. Samples were grouped based on anatomic harvest site and subjected to quantitative polymerase chain reaction for MMP1, MMP2, MMP8, MMP9, MMP12, MMP13, TIMP1, TIMP2, TIMP3, TIMP4, TGFβR1, TGFβR2, and TGFβR3 gene expression analysis, and then to immunohistochemistry for immunolocalization of MMP2, TIMP2, and TGFβR2. Decreased gene expression of MMP12, TIMP2, TIMP3, TIMP4, and TGFβR2 was found in varicose veins when compared to controls. Regarding CVeD clinical progression, two facts arose: results across anatomical regions were uneven; decreased gene expression of MMP9 and TGFβR3 and increased gene expression of MMP2 and TIMP3 were found in advanced clinical stages. Most immunohistochemistry results for tunica intima were coherent with qPCR results. In conclusion, decreased expression of TGFβRs might suggest a reduction in TGF-β1 participation in the MMP/TIMP imbalance throughout CVeD progression. Further studies about molecular events in the varicose vein wall are required and should take into consideration the venous anatomical region and CVeD clinical progression.

Incidental Anatomic Finding of Celiacomesenteric Trunk Associated with 'Nutcracker Phenomenon,' or Compression of the Left Renal Vein

Patient: Female, 91

Final Diagnosis: Nutcracker syndrome • celiacomesenteric trunk

Symptoms: Dyspepsia • dysphagia

Medication: —

Clinical Procedure: —

Specialty: Surgery

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.

Endoluminal application of glass-capped diffuser for ex vivo endovenous photocoagulation

Endovenous laser ablation (EVLA) has frequently been used to treat varicose veins for 20 years. In spite of 90˜95% occlusion rates, clinical complications such as burn and ecchymosis still occur due to excessive thermal injury to perivenous tissue. In the current study, a glass-capped diffusing applicator is designed to validate the feasibility of EVLA as an effective therapeutic device by applying circumferential light distribution. The proposed device is evaluated with a flat fiber as a reference in terms of temperature elevation, fiber degradation, and degree of coagulative necrosis after 532 nm-assisted EVLA at 100 J/cm. The diffusing fiber generates a 40% lower maximum temperature with a 90% lower transient temperature change in blood, compared to the flat fiber. Due to low irradiance (13.5 kW/cm² ) and wide light distribution, the diffuser tip experiences no significant thermal degradation while severe carbonization occurs at the flat fiber tip. Ex vivo tissue tests verify that the diffusing fiber induces circumferential and consistent tissue denaturation to the vein wall (107.8 ± 7.8 µm) along with 19% vessel shrinkage. The proposed glass-capped diffusing applicator can be a feasible therapeutic device for EVLA with minimal complications by entailing low maximum temperatures and uniform tissue denaturation in the venous tissue.

Oral Thrombus: Report of 122 cases with clinically descriptive data

BACKGROUND

The aim of the present study was to assess the frequency and characterize clinic-pathologic aspects of thrombus occurring as a single lesion or in association with other oral pathologies.

MATERIAL AND METHODS

122 cases of thrombus from the oral cavity were retrieved. Information regarding site of the lesion, age, sex and clinical diagnosis or hypothesis and associated lesions were collected from the patients' records.

RESULTS

The lesions occurred in a wide age range but the 5th decade was the most prevalent and female patients were more affected. The most frequent site for the lesion was the lip, followed by tongue, buccal mucosa, alveolar ridge, gingiva, floor of the mouth and vestibule. Thirty-five cases were associated with other vascular anomalies or actinic cheilitis. Microscopically, typical thrombus morphology was present. Organized thrombus presented neovascularization and fibroblasts, associated with hemorrhagic areas.

CONCLUSIONS

Only 4 cases of oral thrombus have been described in the oral cavity. Given the limited number of cases reported, the importance of a thrombus in the oral cavity is not well established. This study contributes to establishing the profile of patients presenting oral thrombus, a lesion not rare but not well documented.

Matrix Metalloproteinases in Remodeling of Lower Extremity Veins and Chronic Venous Disease

The veins of the lower extremity are equipped with efficient wall, contractile vascular smooth muscle (VSM), and competent valves in order to withstand the high venous hydrostatic pressure in the lower limb and allow unidirectional movement of deoxygenated blood toward the heart. The vein wall structure and function are in part regulated by matrix metalloproteinases (MMPs). MMPs are zinc-dependent endopeptidases that are secreted as inactive pro-MMPs by different cells in the venous wall including fibroblasts, VSM, and leukocytes. Pro-MMPs are activated by other MMPs, proteinases, and other endogenous and exogenous activators. MMPs degrade various extracellular matrix (ECM) proteins including collagen and elastin, and could affect other cellular processes including endothelium-mediated dilation, VSM cell migration, and proliferation as well as modulation of Ca²⁺ signaling and contraction in VSM. It is thought that increased lower limb venous hydrostatic pressure increases hypoxia-inducible factors and other MMP inducers such as extracellular matrix metalloproteinase inducer, leading to increased MMP expression/activity, ECM protein degradation, vein wall relaxation, and venous dilation. Vein wall inflammation and leukocyte infiltration cause additional increases in MMPs, and further vein wall dilation and valve degradation, that could lead to chronic venous disease and varicose veins (VVs). VVs are often presented as vein wall dilation and tortuosity, incompetent venous valves, and venous reflux. Different regions of VVs show different MMP levels and ECM proteins with atrophic regions showing high MMP levels/activity and little ECM compared to hypertrophic regions with little or inactive MMPs and abundant ECM. Treatment of VVs includes compression stockings, venotonics, sclerotherapy, or surgical removal. However, these approaches do not treat the cause of VVs, and other lines of treatment may be needed. Modulation of endogenous tissue inhibitors of metalloproteinases (TIMPs), and exogenous synthetic MMP inhibitors may provide new approaches in the management of VVs.

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

Objective

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

Methods

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

Results

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

Conclusions

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

Hair removal-related injuries in the United States, 1991-2014

BACKGROUND

Hair removal practices have changed in frequency and location on the body. Previous research on hair removal injuries has focused on a specific body region, age, or gender.

OBJECTIVE

This study sought to take a broader perspective of hair removal-associated injuries in the United States which sought treatment at emergency departments.

METHODS

Data from the National Electronic Injury Surveillance System (NEISS) from 1991 to 2014 were used to identify hair removal-related injuries. Incidence rates were determined for the overall population and stratified by gender and age category using US Census Bureau population estimates.

RESULTS

From 1991 to 2014, there were an estimated 292 053 hair removal-associated injuries in the United States. The overall incidence rate was highest in 2013 (9/100 000). Those aged 65+ had the highest incidence from 1991 to 2010 with those aged 19-34 having the highest rate starting in 2011. When stratified by body region injured, males had highest injury rates to the face and females had highest rates to the lower limbs. Starting in 2010, those aged 19-34 had higher incidence particularly for pubic and trunk regions.

CONCLUSION

The incidence of hair removal-associated injuries seen by emergency departments increased nearly ninefold between 1991 and 2013. Due to the increased incidence among 19- to 34-year-olds, caution should be taken particularly for this age group when undergoing depilatory practices. Overall, individuals should practice safe and acceptable usage of hair removal products to reduce the risk of injury.

Prolonged Mechanical Circumferential Stretch Induces Metabolic Changes in Rat Inferior Vena Cava

OBJECTIVE/BACKGROUND

Circumferential stretch on the vein wall has been suggested as a potential etiological factor in the development of varicose veins. However, the influence of vein wall stretch on vein metabolism has not yet been explored. The aim of this study was to investigate the effect of short and prolonged mechanical stretch on vein wall metabolism.

METHODS

Circular segments of inferior vena cava from male Sprague-Dawley rats were exposed to normal 0.5-g (nonstretched) or high 2-g (stretched) tension for short (4 h) or prolonged (18 h) duration (five vein segments per group). Contraction response to phenylephrine (10^-5 M) and KCl (96 mM) was elicited to observe the effect of circumferential stretch on vein function. The polar and organic metabolites in vein tissue were extracted using a bilayer extraction method. Aqueous and organic extracts were analyzed using nuclear magnetic resonance spectroscopy and ultra performance liquid chromatography coupled to mass spectrometry, respectively. Data acquired from both analytical platforms were analyzed using mathematical modeling.

RESULTS

Increased concentrations of valine (p = .02) and choline (p = .03) metabolites and triglyceride moieties (p = .03) were observed in veins stretched for 18 h compared with the nonstretched/18 h group.

DISCUSSION

Increased concentrations of branched chain amino acid valine and cell membrane constituent choline indicate increased muscle breakdown and increased metabolism of membrane phospholipids under stretch in an ex-vivo model. Increased intensities of triglyceride moieties in stretched vein segments for 18 h suggest that high pressure may induce an inflammatory response.

CONCLUSION

This study has shown that prolonged mechanical circumferential stretch (18 h) alters the metabolic profile of rat inferior vena cava.

Pregnancy-associated adaptations in [Ca2+]i-dependent and Ca2+ sensitization mechanisms of venous contraction: implications in pregnancy-related venous disorders

Pregnancy is associated with significant adaptations in the maternal hemodynamics and arterial circulation, but the changes in the venous mechanisms during pregnancy are less clear. We hypothesized that pregnancy is associated with alterations in venous function, intracellular free Ca(2+) concentration ([Ca(2+)]i), and Ca(2+)-dependent mechanisms of venous contraction. Circular segments of inferior vena cava (IVC) from virgin and late pregnant (Preg, day 19) Sprague-Dawley rats were suspended between two hooks, labeled with fura-2, and placed in a cuvet inside a spectrofluorometer for simultaneous measurement of contraction and [Ca(2+)]i (fura-2 340/380 ratio). KCl (96 mM), which stimulates Ca(2+) influx, caused less contraction (35.6 ± 6.3 vs. 92.6 ± 19.9 mg/mg tissue) and smaller increases in [Ca(2+)]i (1.67 ± 0.12 vs. 2.19 ± 0.11) in Preg vs. virgin rat IVC. The α-adrenergic receptor agonist phenylephrine (Phe; 10(-5) M) caused less contraction (23.8 ± 3.4 vs. 70.9 ± 12.9 mg/mg tissue) and comparable increases in [Ca(2+)]i (1.76 ± 0.10 vs. 1.89 ± 0.08) in Preg vs. virgin rat IVC. At increasing extracellular Ca(2+) concentrations ([Ca(2+)]e) (0.1, 0.3, 0.6, 1, and 2.5 mM), KCl and Phe induced [Ca(2+)]e-contraction and [Ca(2+)]e-[Ca(2+)]i curves that were reduced in Preg vs. virgin IVC, supporting reduced Ca(2+) entry mechanisms. The [Ca(2+)]e-contraction and [Ca(2+)]e-[Ca(2+)]i curves were used to construct the [Ca(2+)]i-contraction relationship. Despite reduced contraction and [Ca(2+)]i in Preg IVC, the Phe-induced [Ca(2+)]i-contraction relationship was greater than that of KCl and was enhanced in Preg vs. virgin IVC, suggesting parallel activation of Ca(2+)-sensitization pathways. The Ca(2+) channel blocker diltiazem, protein kinase C (PKC) inhibitor GF-109203X, and Rho-kinase (ROCK) inhibitor Y27632 inhibited KCl- and Phe-induced contraction and abolished the shift in the Phe [Ca(2+)]i-contraction relationship in Preg IVC, suggesting an interplay between the decrease in Ca(2+) influx and possible compensatory activation of PKC- and ROCK-mediated Ca(2+)-sensitization pathways. The reduced [Ca(2+)]i and [Ca(2+)]i-dependent contraction in Preg rat IVC, despite the parallel rescue activation of Ca(2+)-sensitization pathways, suggests that the observed reduction in [Ca(2+)]i-dependent contraction mechanisms is likely underestimated, and that the veins without the rescue Ca(2+)-sensitization pathways could be even more prone to dilation during pregnancy. These pregnancy-associated reductions in Ca(2+) entry-dependent mechanisms of venous contraction, if occurring in human lower extremity veins and if not adequately compensated by Ca(2+)-sensitization pathways, may play a role in pregnancy-related venous disorders.

Polymorphisms in the MTHFR and MTR genes and the risk of varicose veins in ethnical Russians

OBJECTIVES

The objective of this study was to study the association of polymorphisms MTHFR C677T (rs1801133) and MTR A2756G (rs1805087) with the risk of varicose veins in ethnical Russians.

METHODS

We genotyped 475 patients with varicose veins, 168 individual without chronic venous disease, and the population-based group of 896 subjects. Association was studied using logistic regression analysis adopting co-dominant, additive, recessive, and dominant models of inheritance.

RESULTS

None of the polymorphisms showed a statistically significant association with the risk of varicose veins.

CONCLUSIONS

Our results provide evidence that the studied polymorphisms do not contribute to genetic susceptibility to varicose veins in ethnical Russians.

Matrix Metalloproteinases as Regulators of Vein Structure and Function: Implications in Chronic Venous Disease

Lower-extremity veins have efficient wall structure and function and competent valves that permit upward movement of deoxygenated blood toward the heart against hydrostatic venous pressure. Matrix metalloproteinases (MMPs) play an important role in maintaining vein wall structure and function. MMPs are zinc-binding endopeptidases secreted as inactive pro-MMPs by fibroblasts, vascular smooth muscle (VSM), and leukocytes. Pro-MMPs are activated by various activators including other MMPs and proteinases. MMPs cause degradation of extracellular matrix (ECM) proteins such as collagen and elastin, and could have additional effects on the endothelium, as well as VSM cell migration, proliferation, Ca(2+) signaling, and contraction. Increased lower-extremity hydrostatic venous pressure is thought to induce hypoxia-inducible factors and other MMP inducers/activators such as extracellular matrix metalloproteinase inducer, prostanoids, chymase, and hormones, leading to increased MMP expression/activity, ECM degradation, VSM relaxation, and venous dilation. Leukocyte infiltration and inflammation of the vein wall cause further increases in MMPs, vein wall dilation, valve degradation, and different clinical stages of chronic venous disease (CVD), including varicose veins (VVs). VVs are characterized by ECM imbalance, incompetent valves, venous reflux, wall dilation, and tortuosity. VVs often show increased MMP levels, but may show no change or decreased levels, depending on the VV region (atrophic regions with little ECM versus hypertrophic regions with abundant ECM) and MMP form (inactive pro-MMP versus active MMP). Management of VVs includes compression stockings, venotonics, and surgical obliteration or removal. Because these approaches do not treat the causes of VVs, alternative methods are being developed. In addition to endogenous tissue inhibitors of MMPs, synthetic MMP inhibitors have been developed, and their effects in the treatment of VVs need to be examined.

Pathogenesis of venous ulcer

The underlying pathophysiology of venous ulceration is venous hypertension, which initiates a complex cascade of cellular humeral events that are then magnified by genetic factors. Hemodynamic abnormalities are features of primary and secondary chronic venous diseases that lead to disease progression. Through a sequence of events, some patients develop venous leg ulcers, if the process is not interrupted. The exact science of the pathophysiology of the progression of chronic venous disease to venous leg ulcers is still in its infancy, but the framework for future study has been established.

Serum homocysteine is associated with the severity of primary chronic venous disease

Objective

This study was conducted to assess whether serum homocysteine concentration was associated with the severity of primary chronic venous disease.

Design

Cross-sectional study.

Methods

A total of 282 primary chronic venous disease patients were enrolled from outpatient vascular services. The severity of venous disease was graded using the Clinical Etiology Anatomy Pathophysiology classification system. The association of serum homocysteine concentration with advanced primary chronic venous disease (C4-6) was assessed using the Mann Whitney U test and logistic regression analysis.

Results

Median (interquartile range) serum homocysteine concentrations were 9.10 µM (7.55–10.75) and 10.40 µM (8.85–13.10) in patients with primary chronic venous disease classified by C1-3 (n = 209) and C4-6 (n = 73) grades, respectively, p < 0.001. Serum homocysteine concentration was positively associated with clinical grade 4–6 after adjusting for other risk factors including age, diabetes, male sex, hypertension, recurrent varicose veins and stroke. Patients with serum homocysteine in the third (odds ratio, 2.76, 95% confidence interval, 1.01–7.54) and fourth (odds ratio 3.29, 95% confidence interval 1.15–9.43) quartiles were more likely to have grade C4-6 chronic venous disease than subjects with serum homocysteine in the first quartile.

Conclusions

Serum homocysteine is positively associated with the severity of primary chronic venous disease and therefore could play a role in promoting chronic venous disease complications.

Assessment of arterial stiffness in patients with chronic lower extremity venous disease: An observational study

OBJECTIVES

Arterial stiffness is associated with major adverse cardiovascular events. Chronic venous insufficiency (CVI) is severe form of chronic venous disease (CVD). The aim of this study is to investigate arterial stiffness by cardio-ankle vascular index (CAVI) in patients with CVI.

METHODS

This observational and cross-sectional study involved 87 subjects with CVI and 86 healthy subjects. All subjects underwent ultrasonography examination. CAVI was measured by VaSera-1000 CAVI instrument.

RESULTS

High density lipoprotein cholesterol (HDL) was significantly lower in patients with CVI than controls (46.83 ± 9.25 mg/dl vs 51.33 ± 11.13 mg/dl, p = 0.004). Body mass index (BMI) was significantly higher in CVI patients than controls (28.53 ± 4.10 kg/m(2) vs 26.37 ± 5.16 kg/m(2), p = 0.003). Ankle brachial index (ABI) was significantly lower in patients with CVI compared to controls (1.08 ± 0.08 vs 1.14 ± 0.11, p < 0.001). CAVI was significantly higher in patients with CVI than controls (7.94 ± 1.37 vs 6.73 ± 1.16, p < 0.001). Mean arterial pressure (MAP) was significantly higher in patients with CVI than control group (105.41 ± 10.77 mmHg vs 99.70 ± 11.17 mmHg, p = 0.001). CAVI (p < 0.001, Odds ratio (OR) = 2.033, 95% Confidence interval (CI) = 1.493-2.768), ABI (p = 0.003, OR = 0.003, 95% CI = 0.001-0.137), female sex (p < 0.001, OR = 3.949, 95% CI = 1.613-9.663), and HDL (p < 0.001, OR = 0.923, 95% CI = 0.883-0.964) were the independent predictors of CVI. A CAVI value > 7.9 had a sensitivity 64.4% and a specificity of 94.7% for predicting the presence of CVI in ROC analysis (area under curve = 0.791, 95% CI = 0.723-0.849, p < 0.001).

CONCLUSION

CAVI is independently increased in CVI patients. Therefore CVI may be accepted a form of vascular sclerosis and vascular system should be evaluated in continuum not isolated.

Venous leg ulceration pathophysiology and evidence based treatment

Venous leg ulceration (VLU) is one of the most predominate medical disorders worldwide and in the western hemisphere it affects around 1.5% of the general population and up to 5% of the elderly population. Unfortunately, this trend will only increase given the growth of an aging population worldwide. Understanding its pathophysiology that begins with venous hemodynamic abnormalities and leads to inflammatory alterations with microcirculatory changes is critical to delivering effective curative therapy. As such, the main component to treatment is reversing the underlying venous hypertension and pro-inflammatory milieu using compression treatment along with various adjuvant therapies. Given its impact, a comprehensive multi-pronged approach to care, treatment and prevention is required to reverse the increasing trend that is observed worldwide.

Efficacy of varicose vein surgery with preservation of the great safenous vein

OBJECTIVE: To evaluate the efficacy of surgical treatment of varicose veins with preservation of the great saphenous vein. METHODS: We conducted a prospective study of 15 female patients between 25 and 55 years of age with clinical, etiologic, anatomic and pathophysiologic (CEAP) classification 2, 3 and 4. The patients underwent surgical treatment of primary varicose veins with great saphenous vein (GSV) preservation. Doppler ultrasonography exams were carried out in the first and third months postoperatively. The form of clinical severity of venous disease, Venous Clinical Severity Score (VCSS) was completed before and after surgery. We excluded patients with history of deep vein thrombosis, smoking or postoperatively use of elastic stockings or phlebotonics. RESULTS: All patients had improved VCSS (p <0.001) and reduction in the diameter of the great saphenous vein (p <0.001). There was a relationship between VCSS and the GSV caliber, as well as with preoperative CEAP. There was improvement in CEAP class in nine patients when compared with the preoperative period (p <0.001). CONCLUSION: The varicose vein surgery with preservation of the great saphenous vein had beneficial effects to the GSV itself, with decreasing caliber, and to the symptoms when the vein had maximum caliber of 7.5 mm, correlating directly with the CEAP. The decrease in GSV caliber, even without complete abolition of reflux, leads to clinical improvement by decreasing the reflux volume.

Low expression of lncRNA-GAS5 is implicated in human primary varicose great saphenous veins

The cellular mechanisms of primary varicose great saphenous veins (GSVs) involve inflammation, apoptosis, and proliferation of local cells and extracellular matrix degradation. Long non-coding RNAs (lncRNAs) play important roles in these cellular processes; however, which and how lncRNAs related to these mechanisms take effect on GSVs remain unclear. By screening lncRNAs that might experience changes in GSV varicosities, we selected the lower expressed lncRNA-GAS5 (growth arrest specific transcript 5) for functional assessments. Silencing of lncRNA-GAS5 promoted cell proliferation and migration, and cell cycle of the human saphenous vein smooth muscle cells (HSVSMCs), whereas overexpressing it inhibited these cellular behaviors and reduced apoptosis of HSVSMCs. RNA pull-down experiment revealed a direct bind of lncRNA-GAS5 to a Ca²⁺-dependent RNA-binding protein, Annexin A2. Further experiments showed that silencing of Annexin A2 reduced the HSVSMCs proliferation and vice versa. In the context of lncRNA-GAS5 knockdown, silencing of Annexin A2 reduced the proliferation of HSVSMCs while overexpression of Annexin A2 increased the proliferation. Thus, the low expression of lncRNA-GAS5 may facilitate HSVSMCs proliferation and migration through Annexin A2 and thereby the pathogenesis of GSV varicosities.

IQGAP1 modulates the proliferation and migration of vascular smooth muscle cells in response to estrogen

Vascular smooth muscle cell (VSMC) proliferation and migration has been proven to be a critical event in the development of varicosity. Variations in estrogen levels, a pathological event related to age and pregnancy, play a role in the pathogenesis of varicosity. Previous studies have reported a different response of VSMCs following estrogen stimulation. However, the exact mechanisms involved have not yet been elucidated. In the present study, we examined the responses of lesion and normal VSMCs treated with 10(-8) M 17β-estradiol (E2) for 24 h. A differential effect of exposure to E2 was observed in these cells. IQ-domain GTPase-activating protein 1 (IQGAP1), a scaffold protein, was overexpressed in the lesion VSMCs and was shown to modulate VSMC proliferation and migration in response to E2. Furthermore, the increased expression of IQGAP1 was found to be intimately associated with a high activity of estrogen receptor α (ERα), which has been implicated in the regulation of VSMC physiological function. Additionally, we found that two critical kinases, Akt and extracellular signal-regulated kinase (ERK), mediated the activation of ERα and VSMC proliferation. According to our results, we thus concluded that high levels of IQGAP1 in VSMCs regulate the physiological reaction of the cells in response to estrogen exposure, and that kinases are involved in the process by mediating ERα activation. In view of the essential role of IQGAP1 in the physiological function of VSMCs, targeting this molecule may prove to be a promising strategy for the treatment of varicosity.

Progression in venous pathology

Aim

To review epidemiologic data on progression of venous pathology in varicose veins and from varicose veins towards chronic venous insufficiency.

Methods

We searched Medline and PubMed for epidemiologic studies concerning progression of venous pathology.

Results

The data suggest that reflux progression may develop from segmental to multisegmental superficial reflux. In younger age, reflux in tributaries and non-saphenous veins is more frequent. In older age, more saphenous reflux develops and more proximal sites seem to be affected. A high proportion of uncomplicated varicose vein (C2) develops skin changes and chronic venous insufficiency (C3–C6). Significant risk factors for the progression of varicose vein towards venous leg ulcers are skin changes, corona phlebectatica, higher body mass index and popliteal vein reflux. During a 13.4-year follow-up period, 57.8% (4.3%/year) of all chronic venous disease patients showed progression of the disease.

Summary

Studies on the progression of venous pathology show a high progression rate of chronic venous disease. More follow-up studies are still needed to get better information about the risk of varicose vein patients for progression to venous leg ulcers and to answer the question which patients may benefit from early varicose vein interventions.

Expression and significance of NELIN and SM22α in varicose vein tissue

The aim of the present study was to investigate the expression of NELIN and SM22α in lower extremity varicose vein tissue, and their association with varicose veins. Tissue samples were collected from 18 patients with lower extremity varicose veins for the experimental group, while normal great saphenous vein tissue was reserved during coronary artery bypass surgery from 14 patients for the controls. Reverse transcription polymerase chain reaction (RT-PCR) analysis was applied to detect the mRNA expression levels of NELIN and SM22α, while immunohistochemical techniques were used to detect the protein expression levels in the normal and abnormal veins. RT-PCR results revealed that the mRNA expression levels of NELIN and SM22α in the experimental group decreased significantly when compared with the control group (P<0.01). In the two groups, immunohistochemical staining demonstrated that NELIN and SM22α were primarily expressed in the cytoplasm of smooth muscle cells, and the expression quantity decreased significantly in the experimental group when compared with the control group (P<0.05). The low expression of SM22α in the primary lower limb varicose vein tissue indicated that the vascular smooth muscle cell layer had transformed from a contractile to a secretory phenotype, which may have resulted in the remodeling of the vein walls and the occurrence of varicose veins. Therefore, NELIN and SM22α were demonstrated to play a key role in the development of varicosity.

Pelvic congestion syndrome: etiology of pain, diagnosis, and clinical management

Pelvic congestion syndrome is associated with pelvic varicosities that result in chronic pelvic pain, especially in the setting of prolonged standing, coitus, menstruation, and pregnancy. Although the underlying pathophysiology of pelvic congestion syndrome is unclear, it probably results from a combination of dysfunctional venous valves, retrograde blood flow, venous hypertension, and dilatation. Asymptomatic women may also have pelvic varicosities, making pelvic congestion syndrome difficult to diagnose. This article explores the etiologies of pain, use of imaging techniques, and clinical management of pelvic congestion syndrome. Possible explanations for the spectrum of pain among women with pelvic varicosities are also discussed.

Immunological aspects of chronic venous disease pathogenesis

Chronic venous disease (CVD) is a very common health problem concerning up to 1/3 of the society. Although venous hypertension and valvular incompetence have been long known to be crucial for development of the illness, its exact aetiology remains unclear. Recent findings indicate that inflammatory processes may be crucial for development of incompetent valves and vein wall remodelling. One of the most interesting theories describes “leucocyte trapping” as the mechanism responsible for elevated vein wall permeability and oxidative stress in the veins. At the same time, the cytokine profile of the blood in incompetent veins has not been thoroughly examined. Popular anti-inflammatory drugs relieve some symptoms but do not have much proved effects in prevention and treatment.

We intend to summarize the existing knowledge of the immunological aspects of CVD in order to emphasize its importance for understanding the aetiology of this illness. We also wish to indicate some aspects that remain to be studied in more detail.

A different way to look at varicose veins

OBJECTIVE

The development of varicose veins is commonly attributed to vessel wall degeneration. The idea that varicose veins occur because of pathological processes, however, is challenged by certain observations. For example, their high prevalence (50% or greater) in many populations makes it statistically "normal" to have varicose veins; their well-established genetic predisposition raises the possibility that this high prevalence reflects a survival benefit. One way to explain this apparent contradiction is to theorize that varicose veins are produced by the same mechanism(s) that lead to the growth and remodeling of other types of blood vessels. If so, being "good" at forming varicose veins may also predispose to being "good" at forming various types of collateral blood vessels when necessary.

METHODS

A selected literature review was conducted. Works chosen for review included those suggesting that: the process of varicose vein formation may share the same basic mechanisms as the formation of collateral veins, arteries, and lymphatic vessels; and clinical outcomes may be different between subjects with and without varicose veins.

RESULTS

Evidence suggests that subjects who are "good" at forming varicose veins may also be "good" at forming various types of collateral vessels, and they may have better overall survival (with less cardiovascular morbidity) than those without varicose veins.

CONCLUSIONS

Varicose veins may be "the price we pay" for an enhanced ability to form collateral vessels when necessary.

Decreased PGE₂ content reduces MMP-1 activity and consequently increases collagen density in human varicose vein

Varicose veins are elongated and dilated saphenous veins. Despite the high prevalence of this disease, its pathogenesis remains unclear.

AIMS

In this study, we investigated the control of matrix metalloproteinases (MMPs) expression by prostaglandin (PG)E₂ during the vascular wall remodeling of human varicose veins.

METHODS AND RESULTS

Varicose (small (SDv) and large diameter (LDv)) and healthy saphenous veins (SV) were obtained after surgery. Microsomal and cytosolic PGE-synthases (mPGES and cPGES) protein and mRNA responsible for PGE₂ metabolism were analyzed in all veins. cPGES protein was absent while its mRNA was weakly expressed. mPGES-2 expression was similar in the different saphenous veins. mPGES-1 mRNA and protein were detected in healthy veins and a significant decrease was found in LDv. Additionally, 15-hydroxyprostaglandin dehydrogenase (15-PGDH), responsible for PGE₂ degradation, was over-expressed in varicose veins. These variations in mPGES-1 and 15-PGDH density account for the decreased PGE₂ level observed in varicose veins. Furthermore, a significant decrease in PGE₂ receptor (EP4) levels was also found in SDv and LDv. Active MMP-1 and total MMP-2 concentrations were significantly decreased in varicose veins while the tissue inhibitors of metalloproteinases (TIMP -1 and -2), were significantly increased, probably explaining the increased collagen content found in LDv. Finally, the MMP/TIMP ratio is restored by exogenous PGE₂ in varicose veins and reduced in presence of an EP4 receptor antagonist in healthy veins.

CONCLUSIONS

In conclusion, PGE₂ could be responsible for the vascular wall thickening in human varicose veins. This mechanism could be protective, strengthening the vascular wall in order to counteract venous stasis.

Aberrantly expressed lncRNAs in primary varicose great saphenous veins

Long non-coding RNAs (lncRNAs) are key regulatory molecules involved in a variety of biological processes and human diseases. However, the pathological effects of lncRNAs on primary varicose great saphenous veins (GSVs) remain unclear. The purpose of the present study was to identify aberrantly expressed lncRNAs involved in the prevalence of GSV varicosities and predict their potential functions. Using microarray with 33,045 lncRNA and 30,215 mRNA probes, 557 lncRNAs and 980 mRNAs that differed significantly in expression between the varicose great saphenous veins and control veins were identified in six pairs of samples. These lncRNAs were sub-grouped and mRNAs expressed at different levels were clustered into several pathways with six focused on metabolic pathways. Quantitative real-time PCR replication of nine lncRNAs was performed in 32 subjects, validating six lncRNAs (AF119885, AK021444, NR_027830, G36810, NR_027927, uc.345-). A coding-non-coding gene co-expression network revealed that four of these six lncRNAs may be correlated with 11 mRNAs and pathway analysis revealed that they may be correlated with another 8 mRNAs associated with metabolic pathways. In conclusion, aberrantly expressed lncRNAs for GSV varicosities were here systematically screened and validated and their functions were predicted. These findings provide novel insight into the physiology of lncRNAs and the pathogenesis of varicose veins for further investigation. These aberrantly expressed lncRNAs may serve as new therapeutic targets for varicose veins. The Human Ethnics Committee of Shanghai East Hospital, Tongji University School of Medicine approved the study (NO.: 2011-DF-53).

Impact of weight loss due to sleeve gastrectomy on shear stress of the femoral vein in morbid obesity

Background

Studies have shown that obesity is associated with venous flow disturbances that lead to changes of the biomechanical forces on the venous wall known as shear stress. We hypothesized that weight loss due to bariatric surgery affects the venous hemodynamics and biomechanical forces on the venous wall. The aim of this study was to evaluate the effects of laparoscopic sleeve gastrectomy (LSG) on the wall shear stress (WSS) and the venous hemodynamics of the femoral vein.

Methods

We studied ten morbidly obese patients who underwent LSG. We investigated venous hemodynamics before, 6 and 12 months after LSG. The femoral vein diameter, cross-sectional area, peak (PeakV) and maximum (TA_max) velocities, WSS, and shear rate (SR) were assessed.

Results

PeakV and TA_max were significantly lower in the obese patients compared with the control group. WSS and SR were significantly lower in the obese patients compared with the control subjects. Venous hemodynamic parameters increased in the postoperative period at baseline compared with 12 months after surgery: PeakV increased from 17.53 (14.25–20.01) cm/s to 25.1 (20.9–30.1) cm/s (P = 0.04) and the TA_max from 12.97 (11.51–14.6) cm/s to 18.46 (13.24–24.13) cm/s (P = 0.057). WSS significantly increased from 0.21 (0.19–0.23) Pa at baseline to 0.31 (0.23–0.52) Pa 12 months after surgery (P = 0.031). SR also significantly increased from 47.92 (43.93–58.55) s⁻¹ at baseline to 76.81 (54.04–109.5) s⁻¹ 12 months after surgery (P = 0.02).

Conclusions

This study showed that weight loss due to LSG significantly changes the biomechanical forces on the femoral vein generated by blood flow.

Does extracellular matrix of the varicose vein wall change according to clinical stage?

OBJECTIVE

The etiology and pathophysiology of chronic venous disease is not fully understood. This study aimed to determine the variation of the extracellular matrix proteins in varicose vein wall according to clinical stage.

MATERIAL AND METHODS

Forty varicose and 10 control veins were sampled from the saphenofemoral junction. The Clinical Etiologic Anatomic Pathophysiologic (CEAP) classification was used in patients with varicose veins. Samples were stained with hematoxylin-eosin, Masson's trichrome, EVG (Elastica-van Gieson) stain and with laminin, fibronectin, tenascin antibodies. Stained samples were examined immuno-histochemically. Changes in extracellular matrix were determined semi-quantitatively using light microscopy.

RESULTS

It was observed that in the early stages (C2-C3) of chronic venous disease, fibrosis is increased in the intima and media layers, with fragmentation in lamina elastica interna, and increased tenascin expression in the intima layer. In advanced stages (C4-C6), the accumulation of tenascin in the intima continued along with fibrosis in the media layer, the thickness of the media layer increased and fibronectin deposition was observed.

CONCLUSION

This study showed that changes first occur in the intima during the early stages of the disease with addition of alterations in the media layer at later stages.

Increased levels of lysosomal cysteinyl cathepsins in human varicose veins: a histology study

Varicose veins are a major chronic venous disease characterised by extensive remodelling of the extracellular matrix architecture in the vascular wall. Although matrix metalloproteinases have been implicated in these pathologic events, little is known about the functional relevance of other protease family members. Here, we studied the distribution of lysosomal cysteine proteases, cathepsins B, L, K, and S, and their endogenous inhibitor, cystatin C, in long saphenous vein specimens from nine normal donors and 18 patients with varicose veins (VVs). Immunohistochemical analysis demonstrated increased levels of cathepsins L, K, B, and S and reduced levels of cystatin C in VVs. This imbalance between cysteinyl cathepsins and cystatin C may favour VV remodelling. To investigate the inflammatory mechanism of their expression, we examined a detailed inflammatory cell profile in VVs, including macrophages, T lymphocytes, and mast cells. Increased numbers of CD3-positive T cells and tryptase-positive mast cells were found in VVs, and enhanced levels of cysteinyl cathepsins were detected from lesion CD3-positive T cells, chymase-positive mast cells, endothelial cells, and smooth-muscle cells. Elevated cathepsins, and their co-localisation to infiltrated inflammatory cells and to vascular cells, suggest that these proteases participate in extracellular matrix degradation in response to inflammation during VV pathogenesis.

Milk flow obstruction caused by varicose vein of the teat in dairy cattle

OBJECTIVE

To describe varicose vein as a cause of obstruction of the teat cistern in dairy cattle and to report therapeutic options and outcome.

STUDY DESIGN

Retrospective case series.

ANIMALS

Dairy cows (n = 22).

METHODS

Medical records (1998-2011) of dairy cows admitted for milking difficulties caused by a teat varicose vein were reviewed. Three treatment approaches were used: sclerotherapy, ligation of the vein associated with sclerotherapy, and phlebectomy. Long-term outcome was obtained ≥ 6 months after treatment and defined as a milking improvement. Descriptive statistics were used to determine the population at risk and a chi square test was used to evaluate the relationship between treatments and outcomes.

RESULTS

Twenty-four teats (22 cows) had a varicose vein. Forequarters were more frequently affected than rear quarters (P < .01). Three sclerotherapies, 12 ligations associated with sclerotherapy and 6 phlebectomies were performed. Five veins were not treated. Overall prognosis with treatment was good (84%) at ≥ 6 months and was not significantly different between treatment types (P = .38). Recurrence of the obstruction by the varicose vein occurred in 3 of 19 teats.

CONCLUSIONS AND CLINICAL RELEVANCE

Several surgical options are available for treatment of teat varicose veins. The overall prognosis of return to normal milking is good.

Quantitative proteomics analysis of varicose veins: identification of a set of differentially expressed proteins related to ATP generation and utilization

Although morphological and anatomical studies indicate that varicose veins are characterized by venous wall weakening and subendothelial fibrosis, the exact underlying biochemical mechanism of their development remains unknown. Additionally, no quantitative proteomic study of venous proteins leading to decreased contractility of varicose veins has been reported to date. Therefore, to elucidate the molecular mechanism of altered vascular contractility, this study performed shotgun proteomic analysis to obtain protein expression profiles in patients with varicose veins. Stable isotope dimethyl labeling coupled with nanoLC-MS/MS revealed downregulation in 12 polypeptides, including myosin light chain kinase, creatine kinase B-type, ATP synthase, phosphoglycerate kinase, and pyruvate kinase. However, analyses of protein species associated with cytoskeletal assembly or with cellular morphology showed no clear up- or down-regulation. These results indicate that defects in ATP generation and utilization may account for the dysfunction of vascular smooth muscle following formation of varicose veins. Collectively, the severity of varicose veins depends on the regulatory roles of various protein factors in the metabolic coordination of physiological functions. This pilot study improves understanding of the pathogenesis of varicose veins and lays the foundation for further validation and clinical translation of biomarkers for targeted therapies in treating this disease.

A systematic review of circulating markers in primary chronic venous insufficiency

OBJECTIVES

The etiology of primary chronic venous insufficiency is poorly understood. This systematic review aimed to summarize published evidence assessing the association of circulating markers with primary chronic venous insufficiency.

METHODS

A search was undertaken through the PubMed database using the terms "venous insufficiency" and "biological marker" or "plasma" or "serum". Search limits included English language, human subjects and studies with publication dates from 1994. Studies which classified patients using the Clinical-Etiology-Anatomy-Pathophysiology system of venous disease were analyzed.

RESULTS

Seventeen studies were included, which have examined > 60 different biomarkers. A total of 13 markers were assessed in >1 study with the number of primary chronic venous insufficiency cases ranging from 41 to 244 and the number of controls ranging from 30 to 144 in these studies. Circulating estradiol, homocysteine and vascular endothelial growth factor were the most consistently associated with primary chronic venous insufficiency.

CONCLUSIONS

Whilst a number of studies have examined biomarkers associated with primary chronic venous insufficiency, further studies are required using improved and standardized approaches on larger populations. Biomarker research may increase pathogenic knowledge and result in opportunities to decrease chronic venous insufficiency burden.

Analysis of the association between an insertion/deletion polymorphism within the 3' untranslated region of COL1A2 and chronic venous insufficiency

BACKGROUND

Chronic venous insufficiency (CVI) is a common cause of leg pain and swelling and is commonly associated with varicose veins. It has significant socioeconomic consequences and is among the most common problems encountered in surgical practice. Although our current understanding of the pathogenesis of CVI is far from clear, there is a growing body of evidence suggesting a genetic contribution to the etiology of CVI.

METHODS

By analyzing 254 CVI cases and 508 healthy controls in a Chinese population, we used a candidate gene approach to evaluate the association between a 7-base pair insertion/deletion (indel) polymorphism (rs3917) in the 3' untranslated region (3'UTR) of the alpha-2 type I collagen gene (COL1A2) and CVI susceptibility. Logistic regression was used to analyze the association between rs3917 and CVI risk, adjusted for sex and age. Computational modeling was used to predict potential molecular mechanisms underlying the association.

RESULTS

Logistic regression analysis revealed that subjects carrying indel or deletion/deletion genotypes had a significantly increased risk for CVI than individuals carrying insertion/insertion genotypes (adjusted odds ratio, 1.64; 95% confidence interval [CI], 1.10-2.45; P = 0.010). Carrying the 7-base pair deletion allele was associated with a 1.60-fold risk for CVI (95% CI, 1.11-2.31; P = 0.008). Computational modeling suggests that the rs3917 insertion allele lies within a predicted binding site (seed region) for microRNA-382 and that the deletion allele alters the affinity of microRNA-mRNA binding by disrupting the local structure of COL1A2 mRNA, presumably allowing for upregulated COL1A2 expression.

CONCLUSIONS

Taken together, our data suggest that common genetic variations in COL1A2 may influence CVI risk, possibly through microRNA-382-mediated regulation. Replication of our studies in other populations will strengthen our understanding of this association.

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.

Relationships between lower limb and trunk discomfort and vascular, muscular and kinetic outcomes during stationary standing work

Standing work is associated with discomfort and symptoms in the trunk and lower limb. However, mechanisms underlying these observations are poorly understood. Moreover, most research on standing-related symptoms has focused on only one region (lower limb or trunk), and has not considered the impact and interactions between vascular, muscular and balance outcomes. We measured foot and soleus blood flow, ankle mean arterial pressure, muscle activity of the plantar and dorsi flexors, gluteus medius and trunk flexors and extensors, center of pressure changes and leg and back discomfort in 18 healthy volunteers performing a repetitive box-folding task for 34 min. Results show significant decreases with time in lower limb muscle activity (p<0.00053), and increases in foot blood flow and center-of-pressure mediolateral sway amplitude (p=0.00066). There were significant time effects on back (p=0.017) and lower limb (p<0.000001) discomfort, the latter significantly correlated (r=0.35) to time-related increases in foot blood volume. No changes were correlated to the increase in back discomfort. Results suggest that the origin of standing-related lower limb discomfort is likely vascular in origin, whereas back discomfort is likely multifactorial, involving muscular, vascular and postural control variables.