Postischemic leukocyte/endothelial cell interactions and microvascular barrier dysfunction in skeletal muscle: cellular mechanisms and effect of Daflon 500 mg

Protective effects of hesperidin in gastric damage caused by experimental ischemia-reperfusion injury model in rats

PURPOSE

This study evaluated the protective effect of hesperidin on injury induced by gastric ischemia-reperfusion.

METHODS

Fifty male Sprague Dawley rats (250-300 g) were divided into five groups: control (C), sham (S), ischemia (I), ischemia-reperfusion (I/R) and hesperidin + ischemia-reperfusion (Hes + I/R). Hesperidin was injected intraperitoneally at the dose of 100 mg/kg one hour before the experimental stomach ischemia-reperfusion. Celiac artery was ligated. After 45 minutes ischemia and 60 minutes reperfusion period, blood samples were obtained under anesthesia. Then, animals were sacrificed, stomach tissues were excised for biochemical, and histopathological analyses were performed. Malondialdehyde levels and superoxide dismutase, glutathione peroxidase activities and total antioxidant status (TAS), total oxidant status (TOS), protein, total thiol parameters were measured in plasma, and tissue homogenate samples. H + E, periodic acid-Schiff, hypoxia inducible factor, terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end-labeling (TUNEL), and proliferating cell nuclear antigen (PCNA) for cell proliferation as immunohistochemical parameters were determined.

RESULTS

Upon biochemical and histopathological assessment, hesperidin decreased stomach tissue changes in comparison with IR group. Ischemia-reperfusion injury led to a considerably increase in malondialdehyde, protein, and TOS levels (p < 0.001) in stomach tissue. Hesperidin treatment significantly decreased malondialdehyde, protein, and TOS levels (p < 0.001). Hesperidin increased superoxide dismutase, TAS, total thiol and glutathione peroxidase activities in comparison with IR group. Hesperidin reduced damage and also increased TUNEL and PCNA immunoreactivity in stomach tissue.

CONCLUSIONS

Hesperidin was able to decrease I/R injury of the stomach tissue due to inhibition of lipid peroxidation and protein oxidation, duration of antioxidant, and free radical scavenger properties. Consequently, hesperidin can provide a beneficial therapeutic choice for preventing stomach tissue ischemia-reperfusion injury in clinical application.

Micronized purified flavonoid fraction in the treatment of hemorrhoidal disease

Hemorrhoidal disease (HD) is common in adults. Treatment is largely conservative, although more invasive procedures may be required. Venoactive drugs such as micronized purified flavonoid fraction (MPFF) are widely used, but a recent and comprehensive review of supporting evidence is lacking. In acute HD, MPFF can reduce HD symptoms such as bleeding, pain, anal discomfort, anal discharge and pruritus. In patients undergoing surgery, postoperative adjunct MPFF consistently reduces pain, bleeding duration and use of analgesia. MPFF treatment is appropriate and effective both as a first-line conservative treatment and as a postoperative adjunct treatment. MPFF reduces the duration of hospital stay following surgery, facilitating a return to normal activity and improving quality of life. MPFF may also prevent HD recurrence.

Micronized Purified Flavonoid Fraction in Hemorrhoid Disease: A Systematic Review and Meta-Analysis

Introduction

Hemorrhoidal disease (HD) is a common and recurrent problem for many adults worldwide. Venoactive drugs, such as micronized purified flavonoid fraction (MPFF; Daflon^®), have been used to treat HD and their clinical benefits have been demonstrated in previous meta-analyses of clinical trials. The aim of this study was to evaluate the efficacy of MPFF across the broader spectrum of signs and symptoms following treatment of patients with HD.

Methods

We performed a systematic review of the literature to identify randomized clinical trials in which MPFF treatment was compared to placebo or no treatment for acute HD or for relief of symptoms after patients had undergone medical management or a surgical procedure to remove hemorrhoids. The main endpoints investigated were bleeding, pain, pruritus, discharge or leakage, and overall improvement. There was no limit on treatment duration.

Results

From 351 unique records retrieved, 11 studies reported in 13 articles were included. On the basis of findings from qualitative analysis, MPFF was reported in most studies to be beneficial in treating bleeding, pain, pruritus, anal discharge/leakage, and tenesmus, and in overall improvement. Quantitative meta-analysis of four studies indicated that MPFF treatment provided significant benefits for bleeding (odds ratio [OR] 0.082, 95% confidence interval [CI] 0.027–0.250; P < 0.001), discharge/leakage (OR 0.12, 95% CI 0.04–0.42; P < 0.001), and overall improvement according to patients (OR 5.25, 95% CI 2.58–10.68; P < 0.001) and investigators (OR 5.51, 95% CI 2.76–11.0; P < 0.001). MPFF also tended to decrease pain (OR 0.11, 95% CI 0.01–1.11; P = 0.06).

Conclusion

Taken together, these results suggest that MPFF treatment can improve the most important signs and symptoms of HD.

Pathophysiological Mechanisms of Chronic Venous Disease and Implications for Venoactive Drug Therapy

Chronic venous disease (CVD) is a common pathology, with significant physical and psychological impacts for patients and high economic costs for national healthcare systems. Throughout the last decades, several risk factors for this condition have been identified, but only recently, have the roles of inflammation and endothelial dysfunction been properly assessed. Although still incompletely understood, current knowledge of the pathophysiological mechanisms of CVD reveals several potential targets and strategies for therapeutic intervention, some of which are addressable by currently available venoactive drugs. The roles of these drugs in the clinical improvement of venous tone and contractility, reduction of edema and inflammation, as well as in improved microcirculation and venous ulcer healing have been studied extensively, with favorable results reported in the literature. Here, we aim to review these pathophysiological mechanisms and their implications regarding currently available venoactive drug therapies.

The Significance of Pain in Chronic Venous Disease and its Medical Treatment

Chronic venous disease (CVeD) is a highly prevalent condition in the general population, and it has a significant impact on quality of life. While it is usually manifested by obvious signs, such as varicose veins and venous ulcers, other symptoms of the disease are less specific. Among the other symptoms, which include heaviness, swelling, muscle cramps and restless legs, pain is the symptom that most frequently compels CVeD patients to seek medical aid. However, there is a substantial discrepancy between pain severity and clinically detectable signs of CVeD, questioned by several opposing studies. Further evaluation is needed to clarify this subject, and to analyse whether pain development predicts objective CVeD progression. General management of CVeD starts with advising lifestyle changes, such as lowering body mass index and treating comorbidities. However, the mainstay of treatment is compression therapy, with the additional use of pharmacological substances. Venoactive drugs proved to be the drugs of choice for symptom alleviation and slowing the progression of CVeD, with micronized purified flavonoid fraction being the most effective one. Interventional therapy is reserved for advanced stages of the disease.

Recommendations for the medical management of chronic venous disease: The role of Micronized Purified Flavanoid Fraction (MPFF)

Scope A systematic review of the clinical literature concerning medical management of chronic venous disease with the venoactive therapy Micronized Purified Flavonoid Fraction was conducted in addition to an investigation of the hemodynamics and mechanism of chronic venous disease. Methods The systematic review of the literature focused on the use of Micronized Purified Flavonoid Fraction (diosmin) which has recently become available in the US, in the management of chronic venous disease. The primary goal was to assess the level of evidence of the role of Micronized Purified Flavonoid Fraction in the healing of ulcers, and secondarily on the improvement of the symptoms of chronic venous disease such as edema. An initial search of Medline, Cochrane Database for Systematic Reviews and Google Scholar databases was conducted. The references of articles obtained in the primary search, including a Cochrane review of phlebotonics for venous insufficiency, were reviewed for additional studies. Studies were included if patients had a diagnosis of chronic venous disease documented with Doppler and Impedance Plethysmography. Studies excluded were those that had patients with arterial insufficiency (Ankle Brachial Index < .6), comorbidity of diabetes, obesity, rheumatological diseases, or if other causes of edema were present (congestive heart failure, renal, hepatic or lymphatic cause), or if the patient population had recent surgery or deep vein thrombosis, or had been using diuretics (in studies of edema). Other elements of the study design were to note specifically the type of compression therapy used in conjunction with Micronized Purified Flavonoid Fraction. Results The literature review yielded 250 abstracts, 65 of which met criteria for further review and 10 papers were selected for consideration in the systematic review. Conclusion In summary, the general level of evidence supports the recommendation that the use of medical therapy with Micronized Purified Flavonoid Fraction has beneficial outcomes without serious adverse events. In the United States, diosmiplex is the only available prescription formulation of Micronized Purified Flavonoid Fraction. It is derived from the rinds of oranges and is categorized as a medical food and not as a drug; and may be a particularly attractive therapy for many chronic venous disease patients because of its favorable safety profile. The Working Group for chronic venous disease concurs with previous guidance by the International European Society for Vascular Surgery in 2015 which recommended the use of Micronized Purified Flavonoid Fraction for the healing of venous ulcers, alone and adjunctive to compression therapy, and for the reduction in symptoms of chronic venous disease such as edema.

Chronic Venous Insufficiency and the Therapeutic Effects of Daflon 500 mg

Chronic venous insufficiency is linked to venous hypertension and forces of shear stress on the endothelium. Venous hypertension depends upon two forces: the weight of a column of blood from the right atrium transmitted through the valveless vena cava and iliac veins to the femoral vein, and pressure generated by contracting skeletal muscles of the leg transmitted through failed perforating veins. When valve failure occurs in superficial axial veins and perforating veins, the venous pressure in the veins and venules of the skin and subcutaneous tissue is raised. The skin changes in chronic venous insufficiency are directly related to the severity of the venous hypertension. Also, pathologic changes in the valves are linked to venous hypertension and leukocyte infiltration and activation. It is hypothesized that acute venous pressure elevations cause a shift in the venous hemodynamics with changes in wall shear stress. This initiates the inflammatory cascade. Daflon 500 mg ameliorates the effects of chronic inflammation. In randomized trials, 60 days of therapy with Daflon at a dosage of 500 mg 2 tablets daily was effective, in addition to elastic compression, in accelerating venous ulcer healing. Because venous insufficiency is linked to venous hypertension and an inflammatory reaction, it appears that Daflon 500 mg 2 tablets daily shows a great potential for accomplishing blockade of the inflammatory cascade.

Clinical acceptability study of micronized purified flavonoid fraction 1000 mg tablets versus 500 mg tablets in patients suffering acute hemorrhoidal disease

OBJECTIVE

To compare the clinical acceptability of micronized purified flavonoid fraction (MPFF) 1000 mg with MPFF 500 mg tablets, administered at the same daily dose in patients suffering non-complicated acute hemorrhoids.

BACKGROUND

MPFF is an established treatment for hemorrhoidal disease.

METHODS

This was a double-blind, multi-center, randomized study. Patients took either MPFF 1000 mg or 500 mg tablets for 7 days (daily dose; 3 g over 4 days followed by 2 g over 3 days). Adverse events were recorded in a patient diary. On day 7, anal pain and bleeding were assessed (visual analog scale [VAS] and Dimitroulopoulos scale, respectively).

RESULTS

Patients (162) were randomized to MPFF 1000 mg (79) and MPFF 500 mg (83). No serious adverse events (AEs) occurred; 10 emergent AEs were considered treatment-related (6 for MPFF 1000 mg and 4 for 500 mg). Both regimens were associated with significant reduction in anal pain (VAS); -2.37 cm MPFF 1000 mg (P < 0.001) and -2.17 cm 500 mg (P < 0.001), with a slight trend in favor of MPFF 1000 mg (mean global reduction -2.27 cm, P < 0.001). Bleeding improved significantly in both groups of patients, 56% of patients on MPFF 1000 mg versus 61% on MPFF 500 mg. Bleeding ceased after treatment in 47% patients on MPFF 1000 mg versus 54% on 500 mg.

CONCLUSION

After 7 days of treatment with MPFF at the same daily dose, both regimens reduced anal pain and bleeding. MPFF 1000 mg had a comparable safety profile to MPFF 500 mg, with the advantage of fewer tablets. Key limitations: Safety study.

Chronology of mitochondrial and cellular events during skeletal muscle ischemia-reperfusion

Peripheral artery disease (PAD) is a common circulatory disorder of the lower limb arteries that reduces functional capacity and quality of life of patients. Despite relatively effective available treatments, PAD is a serious public health issue associated with significant morbidity and mortality. Ischemia-reperfusion (I/R) cycles during PAD are responsible for insufficient oxygen supply, mitochondriopathy, free radical production, and inflammation and lead to events that contribute to myocyte death and remote organ failure. However, the chronology of mitochondrial and cellular events during the ischemic period and at the moment of reperfusion in skeletal muscle fibers has been poorly reviewed. Thus, after a review of the basal myocyte state and normal mitochondrial biology, we discuss the physiopathology of ischemia and reperfusion at the mitochondrial and cellular levels. First we describe the chronology of the deleterious biochemical and mitochondrial mechanisms activated by I/R. Then we discuss skeletal muscle I/R injury in the muscle environment, mitochondrial dynamics, and inflammation. A better understanding of the chronology of the events underlying I/R will allow us to identify key factors in the development of this pathology and point to suitable new therapies. Emerging data on mitochondrial dynamics should help identify new molecular and therapeutic targets and develop protective strategies against PAD.

Targeted inflammation during oncolytic virus therapy severely compromises tumor blood flow

Oncolytic viruses (OVs) are selected or designed to eliminate malignancies by direct infection and lysis of cancer cells. In contrast to this concept of direct tumor lysis by viral infection, we observed that a significant portion of the in vivo tumor killing activity of two OVs, vesicular stomatitis virus (VSV) and vaccinia virus is caused by indirect killing of uninfected tumor cells. Shortly after administering the oncolytic virus we observed limited virus infection, coincident with a loss of blood flow to the interior of the tumor that correlated with induction of apoptosis in tumor cells. Transcript profiling of tumors showed that virus infection resulted in a dramatic transcriptional activation of pro-inflammatory genes including the neutrophil chemoattractants CXCL1 and CXCL5. Immunohistochemical examination of infected tumors revealed infiltration by neutrophils correlating with chemokine induction. Depletion of neutrophils in animals prior to VSV administration eliminated uninfected tumor cell apoptosis and permitted more extensive replication and spreading of the virus throughout the tumor. Taken all together, these results indicate that targeted recruitment of neutrophils to infected tumor beds enhances the killing of malignant cells. We propose that activation of inflammatory cells can be used for enhancing the effectiveness of oncolytic virus therapeutics, and that this approach should influence the planning of therapeutic doses.

Statins inhibit neutrophil infiltration in skeletal muscle reperfusion injury

BACKGROUND

Neutrophil infiltration is a major determinant of ischemia-reperfusion injury (IRI). Statins improve endothelial function by elevating nitric oxide synthase activity and inhibiting adhesion molecule expression and may, therefore, inhibit IRI-induced neutrophil extravasation. Although statins are protective against myocardial IRI and stroke, a role for statins in ameliorating skeletal muscle IRI has not yet been confirmed. This study, therefore, addressed the hypothesis that simvastatin would attenuate the severity of tissue damage during skeletal muscle IRI.

METHODS

Rats were administered simvastatin for 6 d before 4 h hind limb ischemia and 24 h reperfusion. Neutrophil infiltration was assessed using myeloperoxidase (MPO) assays and tissue damage by quantitative immunohistochemical analysis of collagen IV. The effect of reducing nitric oxide levels on the severity of IRI was assessed by administering the NOS inhibitor, N-Imino-L-ornithine (L-NIO), before ischemia.

RESULTS

Simvastatin significantly inhibited IRI-induced MPO activity but not collagen degradation in postischemic skeletal muscle. Inhibition of nitric oxide synthase by L-NIO markedly inhibited neutrophil infiltration and protected against IRI-induced collagen degradation. When both simvastatin and L-NIO were administered before IRI, the IRI-induced elevation in MPO activity was completely inhibited. However, paradoxically, simvastatin counteracted the protective effect of L-NIO against IRI-induced collagen IV degradation.

CONCLUSIONS

The inhibition by simvastatin of IRI-induced neutrophil infiltration in skeletal muscle suggests that statins may be a useful therapy to attenuate the severity of IRI but their precise mechanisms of action remains to be determined. Nitric oxide also plays a cytotoxic, rather than protective, role in mediating IRI in this model.

The effect of purified micronized flavonoid fraction on the healing of anastomoses in the colon in rats

PURPOSE

Anastomotic leakage of colonic and rectal anastomoses is a major complication after large intestine surgery. Many factors influence the healing of colon anastomoses. Flavonoids have been recognized for centuries as physiologically active constituents that are used to treat human diseases. We studied the effects of a clinically used, micronized, purified flavonoid fraction on the healing of colonic anastomosis in rats.

METHODS

Male Sprague-Dawley rats were used. The flavonoid group of rats received 100 mg/kg per day of Daflon for 14 days until surgery. Thereafter, a resection and anastomosis were performed. The bursting pressure of the anastomoses and the hydroxyproline levels of the perianastomotic tissue were determined to evaluate the healing on the third and seventh days of surgery for both flavonoid and control groups.

RESULTS

The bursting pressure of the flavonoid group was higher on the seventh day. The hydroxyproline levels of the flavonoid group were significantly higher than in the control group on both the third and seventh days after surgery.

CONCLUSIONS

Although the micronized purified flavonoid fraction has some inhibitory properties on the healing of the anastomosis, its net effect was to obtain a better anastomotic healing of the colon in rats.

The impact of micronized purified flavonoid fraction on the treatment of acute haemorrhoidal episodes

OBJECTIVE

To evaluate the efficacy and the tolerability of micronized purified flavonoid fraction (MPFF) on symptoms and signs of acute haemorrhoidal disease (HD).

RESEARCH DESIGN AND METHODS

Patients experiencing an acute HD episode for less than 48 h were enrolled in this randomized, double-blind, placebo-controlled study (n = 90 in two hospital-based study centres in Beijing). One group received MPFF, six tablets per day for 4 days followed by four tablets per day for 3 days and the other a placebo. Symptoms and signs of HD were assessed by blinded observers at day 0 (D0), day 4 (D4), and day 7 (D7) on a 4-point severity grading scale (from 1 = absent to 4 = severe). A two-way variance analysis was performed for comparison between groups.

RESULTS

Forty-nine patients (49) in the MPFF group and 41 in the placebo group (mean age 43.2 years [range 18-76 years]), percentage of male gender 54.4%, mean time from onset of acute episode 45.3 h (range 16-48 h) were included in this analysis. No significant differences between groups were seen at baseline in terms of age, gender, and frequency and intensity of symptoms, except for oedema, whose frequency and severity was significantly greater in the MPFF group (p = 0.024). During the 7-day treatment, there was a significant difference in favour of MPFF in the evolution of pain and oedema (p < or = 0.001 at D7) and in bleeding (p = 0.021 at D4, and p = 0.047 at D7). The appreciation of global efficacy by patients (p = 0.007) or investigators (p = 0.006) also favoured MPFF. Blood pressure, heart rate and laboratory parameters remained within normal ranges and were not modified during the study in either group. No patient had to stop the treatment owing to adverse events and only one patient reported gastrointestinal discomfort.

CONCLUSION

MPFF significantly reduced the extent of pain and bleeding in the selected subjects of this study with acute haemorrhoids. The tolerability was similar in patients receiving MPFF to that in patients receiving a placebo during the 7-day duration of the treatment.MPFF can be considered an effective and well-tolerated agent in the treatment of acute episodes of haemorrhoids.

Micronized purified flavonoid fraction may prevent formation of intraperitoneal adhesions in rats

OBJECTIVE

To evaluate the efficacy of an anti-inflammatory and capillary regulator drug, micronized purified flavonoid fraction (MPFF), in the prevention of postoperative formation of adhesions.

DESIGN

A double-blind, controlled study evaluated the efficacy of MPFF in reducing postoperative adhesion formation in a rat model.

SETTING

Animal care facility of an academic research setting.

ANIMAL(S)

Thirty Sprague-Dawley female rats randomly divided into three groups.

INTERVENTION(S)

Starting on day of surgery, group 2 rats received oral MPFF (100 mg/kg per day for 7 days). Group 3 rats were intraperitoneally injected with 5 mL of saline (containing 200 mg/kg per day of MPFF for 3 days). Control rats received no medication. A standardized surgical trauma was applied in all animals. Three weeks after surgery, the rats were killed, and the adhesions were scored according to macroscopic and microscopic scales.

MAIN OUTCOME MEASURE(S)

Postoperative adhesions.

RESULT(S)

Both oral and intraperitoneal administration of MPFF reduced the scores of adhesions according to macroscopic and microscopic scales. There was no difference between the routes of administration.

CONCLUSION(S)

A statistically significant reduction in postoperative formation of adhesions was observed after oral and intraperitoneal administration of MPFF in our experimental animal model. However, further studies are required to reveal its mechanism of action.

Venous Hypertension, Inflammation and Valve Remodeling

OBJECTIVES

To identify possible mechanisms for destruction of valves in chronic venous hypertension and the results of treatment with an anti-inflammatory micronized purified flavonoid fraction.

MATERIAL AND METHODS

The saphenous vein valves in a rat model of venous hypertension caused by a femoral arterial-venous fistula were studied. Studies included femoral venous pressure, valve morphology, femoral venous reflux and selected molecular inflammatory markers as examined by immunohistochemistry. The effects of treatment with the anti-inflammatory micronized purified flavonoid fraction (S 5628, Servier, 50 and 100 mg/kg/day) were investigated.

RESULTS

The femoral venous pressure was elevated close to arterial values for a period of 3 weeks. We then examined the morphology of the veins and selected molecular inflammatory markers were assessed. The results show that in this model venous reflux develops in response to venous hypertension. This can be inhibited by the administration of the anti-inflammatory micronized purified flavonoid fraction (S 5628, Servier, 50 and 100 mg/kg/day). The valve becomes incompetent by a combination of venous dilation and shortening of the valve leaflets. This is not inhibited by treatment with S 5628. The valve leaflets are infiltrated with granulocytes, monocytes and T-lymphocytes, and the endothelial cells express enhanced levels of P-selectin and ICAM-1. Cells in the valves are subject to extensive apoptosis although no enhancement of MMP 2,9 expression could be detected at the three-week time point examined in this study.

CONCLUSIONS

These results indicate that in this model chronic elevation of venous pressure is associated with an inflammatory reaction in venous valves, a process that may lead to their dysfunction, reflux, and upstream elevation of venous pressure. These effects are mitigated by the anti-inflammatory micronized purified flavonoid fraction in a dose dependent manner.

MICRONIZATION ENHANCES THE PROTECTIVE EFFECT OF PURIFIED FLAVONOID FRACTION AGAINST POSTISCHAEMIC MICROVASCULAR INJURY IN THE HAMSTER CHEEK POUCH

1. The present study was designed to evaluate the effect of micronization on the protective effect of the purified flavonoid fraction (MPFF) on increases in macromolecular permeability induced by ischaemia-reperfusion in the hamster cheek pouch microcirculation. 2. Male hamsters (Mesocricetus auratus) were treated orally, twice a day, with vehicle (lactose), MPFF and non-micronized purified flavonoid fraction (PFF) at 5, 20, 80 and 320 mg/kg per day for 10 consecutive days. On the 11th day, cheek pouches of anaesthetized animals were prepared for intravital microscopy. 3. Local ischaemia was obtained by clamping the neck of the everted pouch and the increase in microvascular permeability was quantified as leakage (leaks) of intravenously injected fluorescein isothiocyanate-labelled dextran (FITC-dextran 150; MW = 150 000). 4. Reperfusion, after 30 min ischaemia, resulted in an immediate but reversible increase in post-capillary leakage. The MPFF induced a significant dose-related reduction in the increased permeability, with 83.4% inhibition compared with control at 320 mg/kg per day (19.2 +/- 1.9 vs 115.7 +/- 4.1 leaks/cm2; P < 0.0001). Non-micronized PFF was significantly less effective: only 47.9% inhibition compared with control was observed at 320 mg/kg per day (60.3 +/- 1.0 vs 115.7 +/- 4.1 leaks/cm2; P < 0.0001) and there was no dose-effect relationship. 5. In conclusion, micronization significantly enhances the protective effects of the purified flavonoid fraction on reperfusion injury in the hamster cheek pouch. This improvement is likely to be related to the better absorption of the micronized formulation, which could explain the superior clinical efficacy shown in previous studies.

Myosin light chain phosphorylation in neutrophil-stimulated coronary microvascular leakage

Neutrophil-induced coronary microvascular leakage represents an important pathophysiological consequence of ischemic and inflammatory heart diseases. The precise mechanism by which neutrophils regulate endothelial barrier function remains to be established. The aim of this study was to examine the microvascular endothelial response to neutrophil activation with a focus on myosin light chain kinase (MLCK)-mediated myosin light chain (MLC) phosphorylation, a regulatory process that controls cell contraction. The apparent permeability coefficient of albumin (Pa) was measured in intact isolated porcine coronary venules. Incubation of the vessels with C5a-activated neutrophils induced a time- and concentration-dependent increase in Pa. The hyperpermeability response was significantly attenuated during inhibition of endothelial MLC phosphorylation with the selective MLCK inhibitor ML-7 and transfection of a specific MLCK-inhibiting peptide. In contrast, transfection of constitutively active MLCK elevated Pa, which was abolished by ML-7. In addition to the vessel study, albumin transendothelial flux was measured in cultured bovine coronary venular endothelial monolayers, which displayed a hyperpermeability response to neutrophils and MLCK in a pattern similar to that in venules. Importantly, neutrophil stimulation caused MLC phosphorylation in endothelial cells in a time course closely correlated with that of the hyperpermeability response. Consistently, the MLCK inhibitors abolished neutrophil-induced MLC phosphorylation. Furthermore, immunohistochemical observation of neutrophil-stimulated endothelial cells revealed an increased staining for phosphorylated MLC in association with contractile stress fiber formation and intercellular gap development. Taken together, the results suggest that endothelial MLCK activation and MLC phosphorylation play an important role in mediating endothelial barrier dysfunction during neutrophil activation.

Update on chronic-venous-insufficiency-induced inflammatory processes

The causes of venous ulceration remain unclear. Twentieth-century hypotheses concentrated on the possibility that this problem was caused by failure of oxygen delivery to the skin. However, it has been difficult to substantiate these predictions in practice. Although the presence of tissue hypoxia has been suggested by studies in which transcutaneous oxygen tension has been assessed with transducers heated to unphysiological temperatures, when oxygen measurements are made at room temperature there is little evidence of tissue hypoxia. This has led to the assessment of alternative mechanisms of ulcer development. There has been considerable interest in recent years in the inflammatory processes that surround venous ulceration. A complex sequence of events appears to surround the development of leg ulceration. Increased leukocyte activation has been shown in patients with venous disease as well as increased expression of soluble endothelial adhesion molecules. Histologic studies of the skin in patients with chronic venous disease show a perivascular infiltration of the capillaries of the papillary plexus (the most superficial part of the dermis) with monocytes, macrophages, and connective tissue proteins including fibrin. Fibrosis of the skin and subcutaneous tissues may be initiated by increased gene expression and production of transforming growth factor-beta1. Vascular endothelial growth factor may be involved in the capillary proliferation that has been reported in the skin by a number of authors. Increased expression of several tissue metalloproteinases has been reported both in liposclerotic skin and periulcer skin. The tissue inhibitors of metalloproteinases are also increased and the net result is unclear. Treatment of venous disease using micronized purified flavonoid fraction moderates some of the inflammatory markers, including leukocyte ligand expression and endothelial adhesion molecule shedding. These compounds have also been shown to reduce leukocyte-endothelial adhesion in animal models of ischemia-reperfusion injury. Many inflammatory processes have now been shown to be involved in the development of the skin changes in patients with chronic venous disease. However, the precise sequence of events that leads to leg ulceration is still unclear. Pharmacologic treatments aimed at moderating some of these inflammatory processes are now under investigation as potential ways of treating patients with the more advanced stages of venous disease.

Therapeutic approach to chronic venous insufficiency and its complications: place of Daflon 500 mg

Early manifestations of chronic venous insufficiency (CVI) are edema, hyperpigmentation, and lipodermatosclerosis. Late complications are cutaneous ulceration and delayed healing. The specific hallmarks of this inflammation include CD68-positive infiltration into the dermal tissue, monocytes, and lymphocytes and enhanced endothelial permeability. This may lead to "fibrin cuff" formation. In addition, membrane adhesion molecules are present and cytokine expression is seen. In one experimental model of mesenteric venous hypertension, the inflammatory process was detected in its earliest stages. This was evident in the form of neutrophilic leukocyte adhesion to venular endothelium as well as migration of cells across the endothelium and basement membrane into the interstitial space. Simultaneously, parenchymal cell death was detected. This suggests that the mechanism that triggers the inflammatory reaction is venous hypertension. This may cause venous distension and a shift in fluid shear stress. Our observations suggest that patients with venous insufficiency demonstrate circulatory humoral stimulators for leukocyte activation. Otherwise, there is evidence that the inflammatory reaction is limited to the region of the venous ulceration or at least to the skin areas with severe microangiopathy. It may be that activated leukocytes traverse perivascular cuffs and release active transforming growth factor-beta1 (TGF-beta1) which has been found to be elevated exclusively in areas of clinically active CVI. Surgical intervention markedly decreases the number of dysfunctional vein segments and allows pharmacologic agents to protect normal structures from continuing damage. Daflon 500 mg, the purified micronized flavonoid fraction containing 90% diosmin and 10% hesperidin, acts favorably in venous ulcer treatment by inhibiting the synthesis of prostaglandins and free radicals. It decreases bradykinin-induced microvascular leakage and may act favorably to inhibit leukocyte activation, trapping, and migration. Clinically, edema is reduced, ulcer healing is accelerated, and leukocyte trapping diminished. The action of micronized purified flavonoid fraction is beginning to be better understood, and as further knowledge is gained, better pharmacologic control of CVI is a tantalizing promise.

Clinical benefits of Daflon 500 mg in the most severe stages of chronic venous insufficiency

Chronic venous insufficiency (CVI) affects a large number of people in Western countries, and is responsible for considerable inconvenience, discomfort, suffering, and costs. Micronized purified flavonoid fraction (MPFF, 450 mg diosmin plus 50 mg hesperidin-Daflon 500 mg) is a potent venotropic drug used in the treatment of venous insufficiency. Pharmacological and clinical studies demonstrated the comprehensive mode of action of Daflon 500 mg: it increases venous tone, it improves lymph drainage, and it protects the microcirculation. Clinical international, prospective, multicenter, randomized, controlled studies versus placebo studies documenting the effects of Daflon 500 mg in CVI at advanced stages with edema, skin changes, and venous leg ulcer are reviewed. In edema, one of the most frequent complaints of patients, Daflon 500 mg brings about a significant reduction in leg circumference, thanks to its capacity to inhibit inflammatory reactions and to decrease capillary hyperpermeability. The rationale for the use of Daflon 500 mg for treatment of skin disorders and venous leg ulcer is its action on the microcirculation-damaging processes. Regarding skin changes, Daflon 500 mg has been shown to improve venous trophic disorders, like gravitational (stasis) dermatitis, and dermatofibrosclerosis. In venous leg ulcer, Daflon 500 mg's clinical efficacy has been demonstrated in addition to standard treatment or versus standard treatment alone. Daflon 500 mg, thanks to its comprehensive mode of action on the veins, lymphatics, and microcirculation, is the method of choice not only in the early stages of CVI treatment, but also in the severe stages of this condition, in combination with compression treatment, sclerotherapy, and surgery if appropriate.

Analysis of nitric oxide activity in prevention of reperfusion injury

This project was designed to determine the role of nitric oxide (NO) in the prevention of ischemia-reperfusion injury. Inferiorly based rectus abdominis muscle flaps were elevated in pigs and subjected to 6 hours of ischemia followed by 4 hours of reperfusion. Group I animals received a bolus of L-arginine before reperfusion, and a continuous infusion once flow was restored. Group II animals served as controls and received an equal volume of saline as a bolus and subsequent continuous infusion. Microdialysis was used to measure tissue NO levels, and these were correlated with muscle survival determined by vital staining with nitroblue tetrazolium. The results demonstrated a significant increase in tissue NO levels in L-arginine-supplemented animals (p < 0.05), which in turn correlated with a significant increase in muscle survival (p = 0.0051). These results suggest that administration of supplemental L-arginine to ischemic skeletal muscle during reperfusion results in increased NO production and decreased tissue damage.

Efficacy of Micronized Flavonoid Fraction in Healing of Clean and Infected Wounds

Purified micronized flavonoid fraction, comprising 90% diosmin and 10% hesperidin, is basically used as a phelebotonic and vasculoprotector agent. It also has anti-inflammatory and anti-edematous actions. This study was designed to evaluate the efficacy of micronized flavonoid fraction in clean and infectious wounds. Sixty Guinea pigs were separated into 2 main groups and 6 subgroups. The first three groups had clean wounds and the other three groups had infected wounds contaminated with S. aureus. Then these main groups were separated into 3 subgroups. The first subgroups was treated with 60 mg/kg/day micronized flavonoid fraction per oral, the second ones was treated with topical 60 mg/kg/day micronized flavonoid fraction, and the third ones had no treatment. Infected wounds were obtained by contamining the wounds with S. aureus. There were no significant differences in wound healing between the groups that have clean wounds (p > 0.05). In the groups with infected wounds, orally and topically treated guina pigs had accelerated wound healing compared to the untreated control group (p < 0.05), confirmed with surface area measurements and histopathological evaluation. Healing showed no difference between the groups treated orally and topically. This study showed that oral or topical administration of micronized flavonoid fraction in the infected wounds is beneficial, while it has no significant effect in clean wounds. </hea

Leg Ulcers: Biochemical Factors

Objective:

To review the biochemical mechanisms underlying the development of skin changes leading to ulceration in patients with chronic venous disease.

Methods:

Searches of Medline and Embase medical literature databases were undertaken. Cochrane Reviews were studied for relevant articles. Hand-searching of non-indexed journals was undertaken.

Synthesis:

Increased leucocyte activation has been shown in patients with venous disease as well as increased expression of soluble endothelial adhesion molecules. Histological studies of the skin in patients with chronic venous disease show a pervascular infiltration of the capillaries of the papillary plexus (the most superficial part of the dermis) with monocytes, macrophages and connective tissue proteins including fibrin. Fibrosis of the skin and subcutaneous tissues may be initiated by increased gene expression and production of transforming growth factor-beta1. Vascular endothelial growth factor may be involved in the capillary proliferation that has been reported in the skin by a number of authors. Increased expression of several tissue metalloproteinases (MMPs) has been reported both in lipsclerotic skin and peri-ulcer skin. The tissue inhibitors of metalloproteinases (TIMPs) are also increased and the net result is unclear. Treatment of venous disease using micronised purified flavonoid fraction moderates some of the inflammatory markers, including leucocyte ligand expression and endothelial adhesion molecule shedding. These compounds have also been shown to reduce leucocyte-endothelial adhesion in animal models of ischaemia-reperfusion injury.

Conclusions:

Many inflammatory processes have now been shown to be involved in the development of the skin changes in patients with chronic venous disease. However, the precise sequence of events which leads to leg ulceration is still unclear. Pharmacological treatments aimed at moderating some of these inflammatory processes are now under investigation as potential ways of treating patients with the more advanced stages of venous disease.

Micronized purified flavonidic fraction compared favorably with rubber band ligation and fiber alone in the management of bleeding hemorrhoids: randomized controlled trial

PURPOSE

The aim of this study was to assess the role of micronized purified flavonidic fraction in the management of bleeding nonprolapsed hemorrhoids.

METHODS

Patients were randomly assigned to receive ispaghula husk alone, rubber band ligation plus ispaghula husk, or micronized purified flavonidic fraction plus ispaghula husk. Other colorectal diseases were excluded by colonoscopy. Blinded observers noted the time for bleeding to stop completely, recurrences, and treatment complications.

RESULTS

A total of 162 patients were randomly assigned with no significant differences in the age and gender distributions among the groups. Hemorrhoidal bleeding was relieved most expediently in the micronized purified flavonidic fraction plus ispaghula husk group (ispaghula husk alone n = 66, mean (standard error of the mean) 10.6 (2.3) days; rubber band ligation plus ispaghula husk n = 57, 5.6 (1.1) days; micronized purified flavonidic fraction plus ispaghula husk n = 39, 3.9 (1.2) days; P = 0.03). However, there were no significant differences in the recurrences at six months of follow-up (ispaghula husk alone n = 8 (12 percent); rubber band ligation plus ispaghula husk n = 12 (21 percent); micronized purified flavonidic fraction plus ispaghula husk n = 2 (5.1 percent); P = 0.075). No complications or side-effects were noted.

CONCLUSIONS

micronized purified flavonidic fraction used with fiber supplements rapidly and safely relieved bleeding from nonprolapsed hemorrhoids.

Pharmacologic aspects of a phlebotropic drug in CVI-associated edema

Several phlebotropic drugs, or edema-protecting drugs, are available, the most important of which are found in the gamma-benzopyrone family (flavonoids). gamma-Benzopyrones can be plant extracts, semisynthetic preparations, or synthetic preparations. This family is divided into two different groups: flavones and flavonols, and flavanes (flavanones). The flavone group contains various types of molecule and includes diosmin. Here we discuss the pharmacologic aspects in edema associated with chronic venous insufficiency (CVI) of one of the reference phlebotropic drugs, micronized purified flavonoid fraction (MPFF), a semisynthetic preparation from the diosmin group, which represents the latest improvement in flavonoid formulation. Before we detail the pharmacologic aspects, a brief summary of the pathophysiology of edema in CVI is necessary. Several factors are implicated: the veins, which create the conditions favorable to edema; the microcirculation, which is the site of fluid transfer into the interstitial tissue; and the lymphatics, which have a limited possibility to reduce edema. Major discoveries are currently being made in CVI and the microcirculation. Results of studies show that MPFF decreases capillary permeability and increases capillary resistance, which could partly be explained by inhibition of leukocyte activation, migration, and adhesion. This inhibition is linked to a significant decrease in plasma levels of endothelial adhesion molecules (VCAM-1 and ICAM-1) after MPFF treatment. Thus, the CVI-induced damage to the microcirculation is counteracted by MPFF. The lymphatic system is also improved by MPFF treatment. The lymphagogue activity of MPFF has been demonstrated in experimental animal models and confirmed by microlymphographic measurement in patients suffering from severe CVI. The pharmacologic activity of MPFF in lymphedema was observed in a study using an animal model of acute lymphedema and in a study in patients with upper limb lymphedema secondary to breast cancer treatment. All these findings point to the importance of acting on each factor involved in the formation and maintenance of edema. This pharmacologic activity is indeed reflected by the clinical efficacy on edema observed during treatment with MPFF.

Effects of the phlebotropic drug Daflon 500 mg on postischemic reperfusion injury in striated skin muscle: a histomorphologic study in the hamster

The objective of this study was to investigate the effects of the purified, micronized, flavonoid fraction Daflon 500 mg (S 5682, 90% diosmin and 10% hesperidin) on tissue damage and leukocyte emigration in striated skin muscle after ischemia-reperfusion, as assessed by histomorphometric analysis. The experimental model used was the transparent dorsal skin fold chamber in the awake Syrian golden hamster. Sixty-four animals were randomly allotted to two treatment groups and time points of investigation. Animals were fed with 30 mg kg(-1) body weight Daflon 500 mg (n = 32) or its vehicle, 5% Arabic gum solution (n = 32), as control 8 hours before ischemia. Before induction of a tourniquet ischemia of 4 hours' duration and at 0.5, 2, and 24 hours of reperfusion, tissue sections were preserved for light and electron microscopic analysis (n = seven or eight animals per time point). The number of intravascular and extravascular leukocytes was determined by light microscopic analysis of esterase-positive leukocytes. For quantitative analysis of ischemia-induced endothelial cell damage, the endothelial thickness of capillaries was calculated by a computer-assisted imaging system, whereas the ischemic tissue damage was assessed by means of a score system (grade 0-3) by an independent investigator. The number of emigrated leukocytes was significantly reduced in Daflon 500 mg-treated animals compared with numbers found in control animals. The histomorphologic muscle fiber damage increased after reperfusion in both groups but was significantly reduced in the Daflon 500 mg-treated animals 2 and 24 hours after reperfusion. These results suggest that the emigration of leukocytes plays an important role in the development of postischemic reperfusion injury of striated skin muscle.

Effect of a micronized purified flavonoid fraction on in vivo platelet functions in the rat

The aim of this study was to investigate the effects of a micronized purified flavonoid fraction (MPFF) on in vivo rat platelet functions. Platelet aggregation and disaggregation were evaluated by a noninvasive, automated isotope monitoring system (AimsPlus). Indium-labeled platelets were injected into anesthetized rats and stimulated by adenosine diphosphate (ADP) (10 microg/kg, i.v.) or collagen (50 microg/kg, i.v.). Fibrinogen binding to ex vivo ADP-activated platelets was determined by flow cytometry. MPFF (100 mg/kg, p.o.) significantly reduced ADP-induced platelet aggregation (p<0.05) and increased platelet disaggregation (p<0.05) compared with controls. Moreover, MPFF inhibited collagen-induced platelet aggregation (p<0.001) and increased platelet disaggregation (p<0.01). In addition, fibrinogen binding to 2.5 or 5 microM ADP-stimulated platelets also was reduced significantly (p<0.05 and 0.01, respectively). These results show that MPFF inhibits in vivo rat platelet functions.