Causes of severe chronic venous insufficiency

Effects of Ruscus extract on muscarinic receptors: Is there a role for endothelium derived relaxing factors on macromolecular permeability protection and microvascular diameter changes?

BACKGROUND

Protective effects of Ruscus extract on macromolecular permeability depend on its capacity to stimulate muscarinic receptors on endothelial cells and induce the release of endothelium derived relaxing factors (EDRFs).

OBJECTIVE

To investigate if these effects depend only on activation of muscarinic receptors or if EDRFs release are also necessary. We have also investigated the participation of Ruscus extract on muscarinic-induced release of EDRFs on microvascular diameters.

METHODS

Hamsters were treated daily during two weeks with Ruscus extract (50, 150 and 450 mg/kg/day) and then macromolecular permeability induced by histamine and arteriolar and venular diameters after cyclooxygenase (COX) and nitric oxide synthase (NOS) inhibitors: indomethacin and Nω-Nitro-L-arginine (LNA), respectively applied topically at 10-8M, 10-6M and 10-4M were observed on the cheek pouch preparation.

RESULTS

Ruscus extract decreased macromolecular permeability in a dose-dependent fashion and did not affect microvascular diameters. NOS and COX inhibitors enhanced its effect on microvascular permeability. NOS inhibition reduced arteriolar diameter and COX blocking decreased arteriolar and venular diameters at the lowest dose and increased them at higher doses of Ruscus extract.

CONCLUSION

The protective effect of Ruscus extract on macromolecular permeability seems to be mediated only via muscarinic receptors. Muscarinic activation attenuated vasoconstrictive tone through cyclooxygenase-independent endothelium derived relaxing factors.

Protective Effects of Micronized Purified Flavonoid Fraction (MPFF) on a Novel Experimental Model of Chronic Venous Hypertension

OBJECTIVES

To assess protective effects of micronized purified flavonoid fraction (MPFF) on microcirculation in an original chronic model of hind limb venous hypertension with low blood flow in small animals.

METHODS

Vein ligatures were performed on male hamsters, as follows: A-right femoral vein; A + B-right femoral vein and its right branch; A + C-right femoral vein and its left branch; A + B + C-right femoral and its right and left branches; D-external right iliac vein. In sham operated groups, similar vascular dissections were performed without ligatures. Superficial (epigastric) and central (jugular) venous pressure evaluations were made during a 10 week period. Hamsters subjected to A + B + C and D ligatures were selected for leukocyte rolling and sticking, functional capillary density (FCD), and venular and arteriolar diameter observations. D ligature was selected to evaluate pharmacological treatment efficacy. MPFF (100 mg/kg), concomitant active flavonoids of MPFF (diosmetin, hesperidin, linarin, and isorhoifolin) (10 mg/kg), diosmin (100 mg/kg) or drug vehicle were administered orally during 2 weeks before vein ligature and 6 weeks thereafter.

RESULTS

A, A + B and A + C models maintained venous return through collaterals. From the 2^nd to the 10^th weeks after vein ligatures, A + B + C and D models elicited a progressive increase of superficial venous pressure (3.83 ± 0.65 vs. 8.56 ± 0.72 mmHg, p < .001 and 4.13 ± 0.65 vs. 9.35 ± 0.65 mmHg, p < .001, respectively) with significant changes to the microcirculation. As D model significantly increased superficial venous pressure without affecting central venous pressure, it was used to evaluate the long-term effects of treatment. Compared with vehicle, MPFF, concomitant active flavonoids of MPFF, and diosmin, significantly decreased leukocyte-endothelium interaction and prevented FCD reduction. Only MPFF significantly prevented venular enlargement as observed in the vehicle treated group.

CONCLUSION

MPFF was more effective than diosmin in improving all microvascular variables. The superiority of MPFF over diosmin alone can be explained by the synergistic beneficial effects of the association between diosmin and active flavonoids of MPFF.

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.

Is vein damage the only cause of clinical signs of lower limb chronic venous insufficiency?

Background:Venous insufficiency is a very prevalent disease. Some decades ago a group of patients was identified that had symptoms of venous insufficiency, but no visible anatomic abnormalities. Studies showed that this subset had reduced venous tone, and their condition became known as hypotonic phlebopathy.Objective:To investigate prevalence, age group and variations in body mass index (BMI) among patients with hypotonic phlebopathy.Methodology:A total of 1,960 limbs were examined in 1,017 patients who had been referred for complaints compatible with venous insufficiency. Patients with BMI ≥ 30 were defined as obese. The patients were examined using color Doppler ultrasonography to detect presence or absence of reflux in veins of the lower limbs and were then distributed into two groups as follows: patients with CEAP ≤ 1 and no reflux, diagnosed with hypotonic phlebopathy; or patients with CEAP ≥ 2 and reflux.Results:The study sample comprised 89.7% women and 10.3% men with a mean age of 44.9 years. Hypotonic phlebopathy was more common among the women (p = 0.0001). Obese women were more likely than women who were not obese to have venous symptom etiology involving trunk lesions (p = 0.0017). Among the men, obesity was unrelated to etiology of symptoms (p = 0.5991). Symptomology was more likely to be related to trunk vein damage among older age groups than among younger age groups (p-valor <0.0001).Conclusions:Hypotonic phlebopathy was very prevalent, particularly among young women who were not obese.

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.

Bromelain down-regulates myofibroblast differentiation in an in vitro wound healing assay

Bromelain, a pineapple-derived enzyme mixture, is a widely used drug to improve tissue regeneration. Clinical and experimental data indicate a better outcome of soft tissue healing under the influence of bromelain. Proteolytic, anti-bacterial, anti-inflammatory, and anti-oedematogenic effects account for this improvement on the systemic level. It remains unknown, whether involved tissue cells are directly influenced by bromelain. In order to gain more insight into those mechanisms by which bromelain modulates tissue regeneration at the cellular level, we applied a well-established in vitro wound healing assay. Two main players of soft tissue healing--fibroblasts and microvascular endothelial cells--were used as mono- and co-cultures. Cell migration, proliferation, apoptosis, and the differentiation of fibroblasts to myofibroblasts as well as interleukin-6 were quantified in response to bromelain (36 × 10(-3) IU/ml) under normoxia and hypoxia. Bromelain attenuated endothelial cell and fibroblast proliferation in a moderate way. This proliferation decrease was not caused by apoptosis, rather, by driving cells into the resting state G0 of the cell cycle. Endothelial cell migration was not influenced by bromelain, whereas fibroblast migration was clearly slowed down, especially under hypoxia. Bromelain led to a significant decrease of myofibroblasts under both normoxic (from 19 to 12 %) and hypoxic conditions (from 22 to 15 %), coincident with higher levels of interleukin-6. Myofibroblast differentiation, a clear sign of fibrotic development, can be attenuated by the application of bromelain in vitro. Usage of bromelain as a therapeutic drug for chronic human wounds thus remains a very promising concept for the future.

Prevalência de insuficiência venosa superficial dos membros inferiores em pacientes obesos e não obesos

CONTEXTO: A insuficiência venosa crônica dos membros inferiores é a mais prevalente das doenças venosas. Muito se discute sobre sua etiologia e fisiopatologia. Vários fatores de risco têm sido associados ao seu desenvolvimento, como idade, sexo, dieta, entre outros. A obesidade é um problema de saúde pública e sua incidência tem aumentado. O ecocolor Doppler é um método útil para avaliar a presença de refluxo e/ou obstrução no sistema venoso. OBJETIVO: Comparar a prevalência de insuficiência venosa superficial e sintomas associados em pacientes obesos e não obesos. MÉTODOS: Após pesagem, medição da estatura e exame físico, os pacientes com índice de massa corpórea (IMC) <30 kg/m² e >35 kg/m² e queixas compatíveis com insuficiência venosa foram distribuídos nos grupos I e II, respectivamente. Foram submetidos à realização do ecocolor Doppler dos membros inferiores para avaliação da presença ou não de refluxo. RESULTADOS: Foram examinados 311 membros de 168 pacientes com 25-72 anos. Para análise estatística, foram consideradas queixas de varizes, dor, edema, dermatite, eczema e úlcera, associados ou não. Foi obtido um total de 109 e 104 membros com varizes nos grupos I e II, respectivamente. Queixas de varizes visíveis (p<0,001) e varizes visíveis com dor (p = 0,0118) foram mais prevalentes no grupo I. Queixas de varizes com edema (p<0,001), somente edema (p<0,001) e edema associado a dor (p<0,001) foram mais prevalentes no grupo II. Os dados não mostraram diferença estatisticamente significante na prevalência de varizes entre os grupos I e II. CONCLUSÃO: A prevalência de varizes é semelhante entre os obesos e não obesos; as queixas clínicas diferem entre os grupos e são compatíveis e dependentes da presença de insuficiência venosa.

Recent insights into the causes of chronic leg ulceration in venous diseases and implications on other types of chronic wounds

Venous ulceration represents the most prevalent form of difficult-to-heal wounds and these problematic wounds require a significant amount of healthcare resources for their treatment. In order to develop effective treatment regimens a clearer understanding of the underlying pathological processes that lead to skin breakdown is required. However, to date, most of these studies have tended to focus on describing the pathology of already-established ulcers. By bringing together relevant aspects of diverse disciplines such as inflammation, cardiovascular, and connective tissue biology, we aim to provide an insight into how circulatory abnormalities that are caused by the underlying disease etiology can induce local tissue inflammation resulting in tissue breakdown. Initially this results in internal tissue damage but if the underlying disease is not treated, the internal tissue damage can worsen and lead to open ulceration. This article discusses the cause-and-effect relationships between chronic venous insufficiency and venous ulceration, focusing particularly on the biological processes that lead from the underlying disease condition to overt ulceration. Available evidence also suggests that formation of pressure, diabetic foot and arterial ulcers, and ulcers as results of blood disorders, is also likely to share some of the same biological processes as venous ulcers.