Adhesion molecule expression in postischemic microvascular dysfunction: activity of a micronized purified flavonoid fraction

Efficacy of Diosmin in Reducing Lower-Extremity Swelling and Pain After Total Knee Arthroplasty: A Randomized, Controlled Multicenter Trial

BACKGROUND

Many patients experience lower-extremity swelling following total knee arthroplasty (TKA), which impedes recovery. Diosmin is a semisynthetic flavonoid that is often utilized to treat swelling and pain caused by chronic venous insufficiency. We aimed to evaluate the efficacy and safety of diosmin in reducing lower-extremity swelling and pain as well as in improving functional outcomes following TKA.

METHODS

This study was designed as a randomized, controlled multicenter trial and conducted in 13 university-affiliated tertiary hospitals. A total of 330 patients undergoing TKA were randomized to either receive or not receive diosmin postoperatively. The diosmin group received 0.9 g of diosmin twice per day for 14 consecutive days starting on the day after surgery, whereas the control group received neither diosmin nor a placebo postoperatively. The primary outcome was lower-extremity swelling 1, 2, 3, and 14 days postoperatively. The secondary outcomes were postoperative pain assessed with use of a visual analogue scale, Hospital for Special Surgery score, range of knee motion, levels of the inflammatory biomarkers C-reactive protein and interleukin-6, and complications.

RESULTS

At all postoperative time points, diosmin was associated with significantly less swelling of the calf, thigh, and upper pole of the patella as well as with significantly lower pain scores during motion. However, no significant differences in postoperative pain scores at rest, Hospital for Special Surgery scores, range of motion, levels of inflammatory biomarkers, or complication rates were found between the diosmin and control groups.

CONCLUSIONS

The use of diosmin after TKA reduced lower-extremity swelling and pain during motion and was not associated with an increased incidence of short-term complications involving the outcomes studied. However, further studies are needed to continue exploring the efficacy and safety of diosmin use in TKA.

LEVEL OF EVIDENCE

Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.

Use of Micronized Purified Flavonoid Fraction Together with Rivaroxaban Improves Clinical and Ultrasound Outcomes in Femoropopliteal Venous Thrombosis: Results of a Pilot Clinical Trial

Introduction

The aim of this study was to assess the impact of adding long-term micronized purified flavonoid fraction (MPFF) to standard treatment of femoropopliteal deep vein thrombosis (DVT).

Methods

This pilot, comparative, open-label study with blinded outcome assessor enrolled patients with a first episode of femoropopliteal DVT confirmed by duplex ultrasound scanning (DUS). All participants were randomly allocated to one of two treatment groups: (1) control that received a standard treatment with oral rivaroxaban, and (2) experimental that involved additional treatment with MPFF 1000 mg/day. Both drugs were used for 6 months. Patients were followed for the whole treatment period and underwent DUS every 2 months to determine the degree of recanalization by popliteal (PV), femoral vein (FV), and common femoral vein (CFV) compressibility. Thrombi extension were assessed by the modified Marder score. At the end of the follow-up period, patients were assessed with Villalta and venous clinical severity scales (VCSS). Patients with a Villalta score ≥ 5 were diagnosed with post-thrombotic syndrome (PTS).

Results

Sixty patients were randomized to the control or MPFF groups (n = 30 in each group). There were 40 men and 20 women with a mean age ± SD of 56.3 ± 13.4 years. Clinically unprovoked DVT was recognized in 65% of cases and left side localization in 45%. The mean baseline Marder score was 15.0 ± 4.8 and 11.1 ± 4.3 in the experimental and control groups, respectively (p = 0.002). At 6 months, the mean Villalta score in the MPFF group was significantly lower compared with control (2.9 ± 2.7 versus 5.8 ± 3.0; p < 0.0001). PTS was diagnosed in six patients (20%) and 17 patients (57%) in the experimental and control groups respectively (p = 0.007). A significant difference between the groups was also observed for the VCSS value (2.3 ± 1.9 versus 4.9 ± 1.9; p < 0001). After 6 months of treatment the Marder score decreased to 0.8 ± 1.6 and 2.8 ± 3.5 in the experimental and control groups, respectively (p = 0.006). In the MPFF group, there was a greater reduction in the Marder score (p < 0.0001) and more rapid rate of recanalization for the FV (p < 0.0001), with a non-significant trend for the CFV (p = 0.130) and PV (p = 0.204) compared with the control group. Full recanalization of the PV at 6 months was observed in 24 patients (80%) who had received MPFF, and only 17 patients (57%) in the control group (p = 0.095).

Conclusion

The addition of MPFF to standard therapy for DVT in the form of oral rivaroxaban can reduce the incidence of PTS at 6 months in patients with proximal DVT and increase the speed of deep vein recanalization.

Funding

Les Laboratoires Servier funded the article processing fees, editorial assistance, and open access fee for this manuscript.

Daflon 500 mg: Symptoms and Edema

Patients suffering from any class of the Clinical, Etiological, Anatomical, Pathophysiological (CEAP) classification of chronic venous disease (CVD) may be symptomatic (C0s-C6s). Leg heaviness, discomfort, itching, cramps, pain, paresthesia, and edema (C3) are the most frequent manifestations of CVD and a major reason for medical consultation. Daflon 500 mg (micronized purified flavonoid fraction [MPFF]) is an effective treatment for symptoms and edema in CVD as demonstrated in several randomized controlled studies. A 2-month, double-blind study in 40 patients established the superiority of Daflon 500 mg over placebo with regard to symptoms and objective signs. This was confirmed in another double-blind, placebo-controlled trial (2 months’ treatment, 160 patients), and in the Reflux assEssment and quaLity of lIfe improvEment with micronized Flavonoids (RELIEF) study. The latter included 5,052 patients in 23 countries, using a visual analog scale for evaluating pain, leg heaviness, cramps, and a sensation of swelling. All symptoms showed significant and progressive improvement. The quality-of-life results (scores on the ChronIc Venous Insufficiency quality of life Questionnaire [CIVIQ]) paralleled those of symptoms. The decrease in the ankle and calf circumferences was significantly greater (p<0.001) in the group of patients treated with Daflon 500 mg in two studies, and correlated well with the improvement in the sensation of swelling (p<0.001). This was confirmed with more sophisticated measurement techniques as in the RELIEF study or in a trial assessing edema with an optoelectronic volumeter in 20 patients. A further double-blind, randomized, controlled study established a statistically significant difference in favor of Daflon 500 mg in comparison with diosmin, both on symptoms and edema. The therapeutic efficacy of Daflon 500 mg on CVD symptoms and edema has been demonstrated in double-blind, randomized, controlled studies. Further studies using a new approach may define the most precise and validated methodology for application in future research in phlebology.

PECAM-1 and caveolae form the mechanosensing complex necessary for NOX2 activation and angiogenic signaling with stopped flow in pulmonary endothelium

We showed that stop of flow triggers a mechanosignaling cascade that leads to the generation of reactive oxygen species (ROS); however, a mechanosensor coupled to the cytoskeleton that could potentially transduce flow stimulus has not been identified. We showed a role for KATP channel, caveolae (caveolin-1), and NADPH oxidase 2 (NOX2) in ROS production with stop of flow. Based on reports of a mechanosensory complex that includes platelet endothelial cell adhesion molecule-1 (PECAM-1) and initiates signaling with mechanical force, we hypothesized that PECAM-1 could serve as a mechanosensor in sensing disruption of flow. Using lungs in situ, we observed that ROS production with stop of flow was significantly reduced in PECAM-1(-/-) lungs compared with lungs from wild-type (WT) mice. Lack of PECAM-1 did not affect NOX2 activation machinery or the caveolin-1 expression or caveolae number in the pulmonary endothelium. Stop of flow in vitro triggered an increase in angiogenic potential of WT pulmonary microvascular endothelial cells (PMVEC) but not of PECAM-1(-/-) PMVEC. Obstruction of flow in lungs in vivo showed that the neutrophil infiltration as observed in WT mice was significantly lowered in PECAM-1(-/-) mice. With stop of flow, WT lungs showed higher expression of the angiogenic marker VEGF compared with untreated (sham) and PECAM-1(-/-) lungs. Thus PECAM-1 (and caveolae) are parts of the mechanosensing machinery that generates superoxide with loss of shear; the resultant ROS potentially drives neutrophil influx and acts as an angiogenic signal.

Phytochemicals in ocular health: Therapeutic potential and delivery challenges

Diabetic retinopathy (DR) and age-related macular degeneration (AMD) are the leading causes of blindness in adults. The impact of these conditions on the quality of life is increasing in significance with a rise in life expectancy. The role of hyperglycemia, oxidative stress and inflammatory responses in the development and/or progression of DR and AMD, and several other sight threatening ocular diseases, is well established. In proliferative retinopathy, signals sent by the retina for nourishment, triggers the growth of fragile and abnormal blood vessels. Changes in ocular pressure may lead to rupture of these blood vessels causing severe vision problems. Recent in vitro and preclinical studies demonstrate that certain phytochemicals possessing potent antioxidant and anti-inflammatory activity and ocular blood flow enhancing properties may be very useful in the treatment of, or as a prophylactic measure for, DR and AMD. Apart from these properties they have also been investigated for their anti-bacterial, hormonal, enzyme stimulation, and anti-angiogenic activities. The attractive aspect of these potential therapeutic candidates is that they can act on multiple pathways identified in the etiology of DR, AMD, cataract and other ocular diseases. However, results from clinical trials have been somewhat ambiguous, raising questions about the concentrations of these bioflavonoids achieved in the neural retina following oral administration. Unfortunately, as of date, an efficient noninvasive means to deliver therapeutic agents/candidates to the back-of-the eye is still not available. This review examines some of these promising natural agents and discusses the challenges encountered in delivering them to the posterior segment ocular tissues through the oral route.

Prevention of cisplatin ototoxicity: Efficacy of micronized flavonoid fraction in a guinea pig model

OBJECTIVE

To evaluate the effectiveness of micronized flavonoid fraction in preventing cisplatin ototoxicity in a guinea pig model.

METHODS

This study was conducted on 23 guinea pigs in the Animal Laboratory of Izmir Atatürk Training and Research Hospital. Animals were divided into three groups: Group 1 consisted of eight animals receiving cisplatin only; Group 2 contained eight animals receiving cisplatin+micronized flavonoid fraction; and Group 3 contained seven animals that received micronized flavonoid fraction only. Their cochlear reserve was evaluated by measuring the distortion product otoacoustic emission on days 0 and 7.

RESULTS

In Groups 1 and 2, the intragroup signal-noise ratios were statistically different at all frequencies tested (based on negative ranks, p<0.05). In Group 3, the intragroup signal-noise ratios did not differ significantly at the frequencies tested (p>0.05). Comparison of the three groups showed statistically significant differences among the groups (p<0.05). The post hoc Bonferroni correction showed statistically significant differences among all three groups (p<0.016). The median signal-noise ratio of the three groups tended to increase (z-value was positive for all the frequencies tested; p<0.01).

CONCLUSION

Micronized flavonoid fraction (Daflon) is effective against cisplatin-induced ototoxicity in guinea pigs.

Evaluation of the intravenous and topical routes for ocular delivery of hesperidin and hesperetin

PURPOSE

The objective of this study was to determine the ocular bioavailability of hesperidin and hesperetin, especially with respect to their distribution into the posterior segment of the eye, following systemic and topical administration in rabbits.

METHODS

Hesperidin and hesperetin were administered either intravenously or topically to male New Zealand white (NZW) rabbits. Vitreous humor and plasma samples were collected after intravenous administration and analyzed to estimate the concentrations of the parent compounds and their metabolites. Ocular tissue concentrations, obtained on topical administration of hesperidin and hesperetin, were also determined.

RESULTS

In the systemic circulation, hesperidin and hesperetin were rapidly metabolized into their glucuronides, which are extremely hydrophilic in nature. Vitreal samples did not demonstrate any detectable levels of hesperidin/hesperetin following intravenous administration. Topical administration produced significant concentrations of hesperidin/hesperetin in all the ocular tissues tested at the 1 and 3 hours time points postdosing, with hesperetin showing higher levels compared to hesperidin. However, only low levels were generated in the vitreous humor. Inclusion of a penetration enhancer, benzalkonium chloride (BAK), improved the back-of-the-eye hesperetin levels.

CONCLUSIONS

Ocular delivery of hesperidin/hesperetin via the systemic route does not seem to be feasible considering the rapid generation of the hydrophilic metabolites. Topical application appears to be more promising and needs to be further developed/refined.

Synthesis of PECAM-1-specific 64Cu PET imaging agent: evaluation of myocardial infarction caused by ischemia-reperfusion injury in mouse

A PECAM-1 specific PET imaging agent, PECAM-1-Ab-DOTA-(64)Cu, was synthesized by conjugating the anti-mouse PECAM-1 antibody with 2,2',2",2"'-(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid (DOTA) and subsequent labeling with (64)Cu. Positron Emission Tomography (PET) was successfully performed in a mouse model of myocardial infarction (MI) induced by an ischemia/reperfusion (I/R) injury, indicating the elevated expression of PECAM-1.

Diosmin protects rat retina from ischemia/reperfusion injury

OBJECTIVE

Diosmin, a natural flavone glycoside, possesses antioxidant activity and has been used to alleviate ischemia/reperfusion (I/R) injury. The aim of this study was to clarify whether the administration of diosmin has a protective effect against I/R injury induced using the high intraocular pressure (IOP) model in rat retina, and to determine the possible antioxidant mechanisms involved.

METHODS

Retinal I/R injury was induced in the rats by elevating the IOP to 110 mmHg for 60 min. Diosmin (100 mg/kg) or vehicle solution was administered intragastrically 30 min before the onset of ischemia and then daily after I/R injury until the animals were sacrificed. The levels of malondialdehyde (MDA) and the activities of total-superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) in the retinal tissues were determined 24 h after I/R injury. At 7 days post-I/R injury, electroretinograms (ERGs) were recorded, and the density of surviving retinal ganglion cells (RGCs) was estimated by counting retrograde tracer-labeled cells in whole-mounted retinas. Retinal histological changes were also examined and quantified using light microscopy.

RESULTS

Diosmin significantly decreased the MDA levels and increased the activities of T-SOD, GSH-Px, and CAT in the retina of rats compared with the ischemia group (P<0.05), and suppressed the I/R-induced reduction in the a- and b-wave amplitudes of the ERG (P<0.05). The thickness of the entire retina, inner nuclear layer, inner plexiform layer, and outer retinal layer and the number of cells in the ganglion cell layer were significantly less after I/R injury (P<0.05), and diosmin remarkably ameliorated these changes on retinal morphology. Diosmin also attenuated the I/R-induced loss of RGCs of the rat retina (P<0.05).

CONCLUSION

Diosmin protected the retina from I/R injury, possibly via a mechanism involving the regulation of oxidative parameters.

How we can improve patients’ comfort after Milligan-Morgan open haemorrhoidectomy

AIM: To demonstrate the value of Diosmin (flavonidic fraction) in the management of post-haemorhoidectomic symptoms.

METHODS: Eighty-six consecutive patients with grades III and IV acute mixed hemorrhoids admitted to the Anorectal Surgical Department of First Affiliated Hospital, Xinjiang Medical University from April 2009 to April 2010, were enrolled in this study. An observer-blinded, randomized trial was conducted to compare post-haemorhoidectomic symptoms with use of Diosmin flavonidic fraction vs placebo. Eighty-six patients were randomly allocated to receive Diosmin flavonidic fraction 500 mg for 1 wk (n = 43) or placebo (n = 43). The Milligan-Morgan open haemorrhoidectomy was performed by a standardized diathermy excision method. Pain, bleeding, heaviness, pruritus, wound edema and mucosal discharge were observed after surgery. The postoperative symptoms and hospitalization time were recorded.

RESULTS: The mean age of the Diosmin group and controls was 53.2 and 51.3 years, respectively. In Diosmin group, haemorrhoid piles were of the third degree in 33 patients and the fourth degree in 10; and in the control group, 29 were of the third degree and 14 were of the fourth degree. There was no statistically significance in age, gender distribution, degree and number of excised haemorrhoid piles, and the mean duration of haemorrhoidal disease between the two groups. There was a statistically significant improvement in pain, heaviness, bleeding, pruritus from baseline to the 8th week after operation (P < 0.05). Patients taking Diosmin had a shorter hospitalization stay after surgery (P < 0.05). There was also a significant improvement on the proctoscopic appearance (P < 0.001). However, there was no statistical difference between the two groups in terms of wound mucosal discharge. Two patients experienced minor bleeding at the 8th week in Diosmin group, and underwent surgery.

CONCLUSION: Diosmin is effective in alleviating postoperational symptoms of haemorrhoids. Therefore, it should be considered for the initial treatment after haemorrhoid surgery. However, further prospective randomized trials are needed to confirm the findings of this study.

Antioxidant capacity of hesperidin from citrus peel using electron spin resonance and cytotoxic activity against human carcinoma cell lines

CONTEXT

Hesperidin is a flavonoid that has various pharmacological activities including anti-inflammatory, antimicrobial and antiviral activities.

OBJECTIVE

The aim of the study is the isolation of hesperidin from the peel of Citrus sinensis L. (Rutaceae), and the evaluation of its antioxidant capacity and cytotoxicity against different human carcinoma cell lines.

MATERIALS AND METHODS

In the present work, hesperidin is identified and confirmed using chromatographic and spectral analysis. To correlate between hesperidin concentration and antioxidant capacity of peel extracts, extraction was carried out using 1% HCl-MeOH, MeOH, alkaline solution, the concentration of hesperidin determined qualitatively and quantitatively using high performance thin layer chromatography (HPTLC), high performance liquid chromatography (HPLC) analysis, in vitro antioxidant capacity of hesperidin and the extracts against free radical diphenylpicrylhydrazyl (DPPH•) performed using an electron spin resonance spectrophotometer (ESR). Cytotoxic assay against larynx, cervix, breast and liver carcinoma cell lines was performed.

RESULTS

Hesperidin was found to be moderately active as an antioxidant agent; its capacity reached 36%. In addition, the results revealed that hesperidin exhibited pronounced anticancer activity against the selected cell lines. IC₅₀ were 1.67, 3.33, 4.17, 4.58 µg/mL, respectively.

DISCUSSION AND CONCLUSION

Orange peels are considered to be a cheap source for hesperidin which may be used in the pharmaceutical industry as a natural chemopreventive agent. Hesperidin and orange peel extract could possess antioxidant properties with a wide range of therapeutic applications.

Mechanisms of flavonoid protection against myocardial ischemia-reperfusion injury

Flavonoids have long been acknowledged for their unique antioxidant properties, and possess other activities that may be relevant to heart ischemia-reperfusion. They may prevent production of oxidants (e.g. by inhibition of xanthine oxidase and chelation of transition metals), inhibit oxidants from attacking cellular targets (e.g. by electron donation and scavenging activities), block propagation of oxidative reactions (by chain-breaking antioxidant activity), and reinforce cellular antioxidant capacity (through sparing effects on other antioxidants and inducing expression of endogenous antioxidants). Flavonoids also possess anti-inflammatory and anti-platelet aggregation effects through inhibiting relevant enzymes and signaling pathways, resulting ultimately in lower oxidant production and better re-establishment of blood in the ischemic zone. Finally, flavonoids are vasodilatory through a variety of mechanisms, one of which is likely interaction with ion channels. These multifaceted activities of flavonoids raise their utility as possible therapeutic interventions to ameliorate ischemia-reperfusion injury.

Exploration of Emodin to treat alpha-naphthylisothiocyanate-induced cholestatic hepatitis via anti-inflammatory pathway

Emodin, 1,3,8-trihydroxy-6-methyl-anthraquinone, is an anthraquinone derivative from the roots of Rheum officinale Baill that has been used to treat many diseases in digestive system for thousands of years. This study is to disclose the mechanism of Emodin to treat cholestatic hepatitis via anti-inflammatory pathway. Rats were divided into Emodin, ursodeoxycholic acid, Dexamethasone, model and blank control groups with treatment of respective agent after administration of alpha-naphthylisothiocyanate. At 24 h, 48 h and 72 h time points after administration, liver function, pathological changes of hepatic tissue, tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, myeloperoxidase (MPO), malondialdehyde (MDA), superoxide dismutase (SOD), cytokine-induced neutrophil chemoattractant (CINC)-1, macrophage inflammatory protein (MIP)-2, intercellular adhesion molecule (ICAM)-1, nuclear factor (NF)-kappaB and early growth response (Egr)-1, nitric oxide (NO) and inducible nitric oxide synthase (iNOS) were detected. As a result, compared to the controls, Emodin had a notable effect on rat's living condition, pathological manifestation of hepatic tissue, total bilirubin, direct bilirubin, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) (P<0.05), but had little effect on alkaline phosphatase (ALP), gamma-glutamyltransferase (GGT) and total bile acid. With Emodin intervention, levels of TNF-alpha, IL-6, MPO, MDA, CINC-1, MIP-2, ICAM-1 and translocation of NF-kappaB were remarkably decreased, and levels of NO and iNOS were markedly increased (P<0.05). Emodin had no effect on Egr-1. In conclusion, Emodin has a protective effect on hepatocytes and a restoring activity on cholestatic hepatitis by anti-inflammation. The effects are mainly due to antagonizing pro-inflammatory cytokines and mediators, inhibiting oxidative damage, improving hepatic microcirculation, reducing impairment signals, and controlling neutrophil infiltration.

Enhanced bioavailability of verapamil after oral administration with hesperidin in rats

The aim of this study was to investigate the effects of hesperidin on the pharmacokinetics of verapamil and its major metabolite, norverapamil, in rats. The pharmacokinetic parameters of verapamil and norverapamil in rats were measured after the oral administration of verapamil (9 mg/kg) in the presence or absence of hesperidin (3 or 10 mg/kg). Compared to the control group, the presence of hesperidin significantly (p<0.01) increased the area under the plasma concentration-time curve (AUC) of verapamil by 71.1-96.8% and the peak concentration (C(max)) of verapamil by 98.3-105.2%. Hesperidin significantly (p<0.01) decreased the total plasma clearance (CL/F) of verapamil by 41.6-49.2% in rats. However there was no significant change in the time to reach the peak plasma concentration (T(max)), the elimination rate constant (K(el)) and the terminal half-life (T(1/2)) of verapamil in the presence of hesperidin. The AUC and C(max) of norverapamil were significantly (p<0.05) higher in rats co-administrated with hesperidin than those of the control. Consequently hesperidin significantly enhanced bioavailability of verapamil in rats. These results might be due to the decreased efflux and metabolism of verapamil in the intestine. Drug interactions should be concerned in the clinical setting when verapamil is used concomitantly with hesperidin or hesperidin-containing dietary.

Mechanisms in Experimental Venous Valve Failure and their Modification by Daflon© 500 mg

OBJECTIVES

To characterize the acute response of the vein wall to venous hypertension and associated altered fluid shear stress and to test the effect of micronized purified flavonoid fraction (MPFF, Daflon 500), on this response.

MATERIAL AND METHODS

A femoral arteriovenous fistula was created in Wistar rats (n=48). A cohort of 24 rats received oral treatment with MPFF (100 mg/kg/day body weight), 24 rats underwent the arteriovenous fistula procedure and received no treatment. At days 1, 7 and 21 the animals (n=8 at each time point) were killed. Experimental parameters measured included limb circumference, blood flow at the sapheno-femoral junction, leukocyte infiltration and gelatinase activity (matrix metalloproteinase, MMP).

RESULTS

The acute rise in venous hypertension was accompanied by limb edema and venous reflux together with an eventual loss of valve leaflets in the saphenous vein. There was an increase in granulocyte and macrophage infiltration into the venous wall and the surrounding tissue, and a lesser increase in T- and B-lymphocyte infiltration. These changes were accompanied by a local increase in the proteolytic enzymes, MMP-2 and MMP-9. Administration of MPFF reduced the edema and lessened the venous reflux produced by the acute arteriovenous fistula. Decreased levels of granulocyte and macrophage infiltration into the valves were also observed compared with untreated animals.

CONCLUSIONS

Venous hypertension caused by an arteriovenous fistula resulted in the development of venous reflux and an inflammatory reaction in venous valves culminating in their destruction. MPFF was able to delay the development of reflux and suppress damage to the valve structures in this rat model of venous hypertension.

Ethanol preconditioning protects against ischemia/reperfusion-induced brain damage: role of NADPH oxidase-derived ROS

Ethanol preconditioning (EtOH-PC) refers to a phenomenon in which tissues are protected from the deleterious effects of ischemia/reperfusion (I/R) by prior ingestion of ethanol at low to moderate levels. In this study, we tested whether prior (24 h) administration of ethanol as a single bolus that produced a peak plasma concentration of 42-46 mg/dl in gerbils would offer protective effects against neuronal damage due to cerebral I/R. In addition, we also tested whether reactive oxygen species (ROS) derived from NADPH oxidase played a role as initiators of these putative protective effects. Groups of gerbils were administered either ethanol or the same volume of water by gavage 24 h before transient global cerebral ischemia induced by occlusion of both common carotid arteries for 5 min. In some experiments, apocynin, a specific inhibitor of NADPH oxidase, was administered (5 mg/kg body wt, i.p.) 10 min before ethanol administration. EtOH-PC ameliorated behavioral deficit induced by cerebral I/R and protected the brain against I/R-induced delayed neuronal death, neuronal and dendritic degeneration, oxidative DNA damage, and glial cell activation. These beneficial effects were attenuated by apocynin treatment coincident with ethanol administration. Ethanol ingestion was associated with translocation of the NADPH oxidase subunit p67(phox) from hippocampal cytosol fraction to membrane, increased NADPH oxidase activity in hippocampus within the first hour after gavage, and increased lipid peroxidation (4-hydroxy-2-nonenal) in plasma and hippocampus within the first 2 h after gavage. These effects were also inhibited by concomitant apocynin treatment. Our data are consistent with the hypothesis that antecedent ethanol ingestion at socially relevant levels induces neuroprotective effects in I/R by a mechanism that is triggered by ROS produced through NADPH oxidase. Our results further suggest the possibility that preconditioning with other pharmacological agents that induce a mild oxidative stress may have similar therapeutic value for suppressing stroke-mediated damage in brain.

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.

Bioavailability of glucosyl hesperidin in rats

Glucosyl hesperidin (G-hesperidin) is a water-soluble derivative of hesperidin. We compared the absorption and metabolism of G-hesperidin with those of hesperidin in rats. After oral administration of G-hesperidin or hesperidin to rats, hesperetin was detected in sera hydrolyzed with beta-glucuronidase, but it was not detectable in unhydrolyzed sera. Serum hesperetin was found more rapidly in rats administered G-hesperidin than in those administered hesperidin. The area under the concentration-time curve for hesperetin in the sera of rats administered G-hesperidin was approximately 3.7-fold greater than that of rats administered hesperidin. In the urine of both administration groups, hesperetin and its glucuronide were found. Urinary excretion of metabolites was higher in rats administered G-hesperidin than in those administered hesperidin. These results indicate that G-hesperidin presents the same metabolic profile as hesperidin. Moreover, it was concluded that G-hesperidin is absorbed more rapidly and efficiently than hesperidin, because of its high water solubility.

Effect of hypothermia and HTK on the microcirculation in the rat cremaster muscle after ischaemia

Hypothermia is an important preservation method for tissues and solid organs. The aim of the present study was to assess in rat cremaster muscle the effect of hypothermia, without or with pre-ischaemic HTK (histidine-tryptophan-ketoglutarate–Bretschneider solution) perfusion, on microvascular consequences of 4 or 6 h ischaemia and 2 h of reperfusion. Intravital microscopy was applied to examine capillary perfusion and leucocyte–endothelium interactions. The cremaster muscle was subjected to 4 or 6 h of cold (4 °C) or warm (33–34 °C) ischaemia and 2 h of reperfusion. Measurements were performed at baseline, prior to HTK perfusion and ischaemia, and at 0, 1 and 2 h after blood flow restoration. Hypothermia completely prevented the 50% reduction in capillary perfusion that was observed previously at start of reperfusion after 4 h warm ischaemia. After 6 h of warm ischaemia, perfusion resumed in only 45% of capillaries and remained at this low level during reperfusion. In contrast, only a slight decrease (<10%) in capillary perfusion was observed after 6 h of cold ischaemia. Pre-ischaemic HTK perfusion had no beneficial effect on tissue perfusion. Both hypothermia and HTK attenuated the significant increase in venular leucocyte–vessel wall interactions, which was observed after 4 h of warm ischaemia in a previous study. Combined application of both interventions had no additional effects. After 6 h of warm ischaemia, no increase in leucocyte–vessel wall interactions was observed, possibly due to venular flow reduction. In conclusion, hypothermia preserves capillary perfusion and prevents an increase in leucocyte–vessel wall interactions during reperfusion after muscle tissue ischaemia. Preischaemic perfusion of the vasculature with HTK does not improve the effects of cold storage on tissue perfusion, but attenuates the inflammatory response independently of temperature effect.

Vascular and anti-oxidant actions of flavonols and flavones

1. Flavonols and flavones are plant-derived polyphenolic compounds that are commonly consumed in the diet. Epidemiological studies indicating that high dietary intake of flavonols reduces the risk of mortality due to coronary heart disease have provoked interest in the mechanism of this cardioprotective effect. 2. We have investigated the structure-activity relationships of a range of flavonols and flavones with regard to their vascular relaxant and anti-oxidant activity. In rat isolated thoracic aorta, the synthetic flavonol 3',4'-dihydroxyflavonol (DiOHF) was found to be a significantly more potent vasorelaxant than the naturally occurring compounds chrysin, apigenin, luteolin, quercetin and fisetin. Similarly, DiOHF was significantly more potent than those compounds in the inhibition of calcium-induced contraction of the rat aorta. 3. 3',4'-Dihydroxyflavonol was also found to significantly inhibit superoxide radical generation in a cell-free system in the presence of xanthine/xanthine oxidase or by rat isolated aorta in the presence of NADPH. In the presence of oxidant stress generated by pyrogallol or xanthine/xanthine oxidase, endothelium-dependent relaxation of rat aortic rings was impaired. 3',4'-Dihydroxyflavonol was able to significantly improve endothelium-dependent relaxation in the presence of those oxygen radical generators. 4. In addition, DiOHF was found to significantly improve dilatation in the rat hindquarters vasculature after exposure to ischaemia and reperfusion. 3',4'-Dihydroxyflavonol was found to be equally effective whether applied before ischaemia or during ischaemia just before reperfusion. 5. In conclusion, DiOHF is an effective vasodilator and anti-oxidant that is able to prevent vascular reperfusion injury. We suggest that DiOHF may be useful as an adjunct to thrombolytic therapy in the management of reperfusion injury.

3′, 4′-Dihydroxyflavonol Enhances Nitric Oxide Bioavailability and Improves Vascular Function after Ischemia and Reperfusion Injury in the Rat

We hypothesized that 3',4'-dihydroxyflavonol (DiOHF) by scavenging superoxide anions (O2-*) would increase the bioavailability of NO and potentiate NO-mediated relaxation in the rat aorta. Furthermore we hypothesized that DiOHF, by its antioxidant activity, would preserve responses to acetylcholine (ACh) in the presence of O2-* generators in the aorta in vitro and after ischemia and reperfusion of the rat hindquarters vasculature in situ. Using lucigenin-enhanced chemiluminescence we demonstrated that DiOHF caused a concentration-dependent reduction in O2-* accumulation whether generated by xanthine/xanthine oxidase in a cell-free system or by rat isolated aorta in the presence of NADPH. DiOHF also prevented the inhibitory effects of xanthine/xanthine oxidase and pyrogallol on vasorelaxation to ACh and sodium nitroprusside (SNP) in the rat aorta in vitro, and attenuated the vascular dysfunction caused by 2 h ischemia and 2 h reperfusion (I/R) in the rat hindquarters. I/R significantly reduced the dilator responses to both ACh and SNP; however, this effect was attenuated when DiOHF was given before the onset of ischemia or reperfusion. In conclusion, DiOHF, by scavenging O2-*, increases the relaxant activity of ACh and SNP and reduces the degree of inhibition of xanthine/xanthine oxidase or pyrogallol on the response to ACh. DiOHF reduces the adverse effects of I/R on vascular function by increasing NO bioavailability suggesting that it may be useful in preventing reperfusion injury.

Micronised purified flavonoid fraction: a review of its use in chronic venous insufficiency, venous ulcers and haemorrhoids

Micronised purified flavonoid fraction (MPFF) [Daflon 500 mg], an oral phlebotropic drug consisting of 90% micronised diosmin and 10% flavonoids expressed as hesperidin, improves venous tone and lymphatic drainage, and reduces capillary hyperpermeability by protecting the microcirculation from inflammatory processes. The absorption of diosmin is improved by its micronisation to particles with a diameter <2 microm. Compared with placebo, MPFF 500 mg twice daily significantly decreased ankle or calf circumference, and improved many symptoms of chronic venous insufficiency (CVI) and plethysmographic parameters in two randomised, double-blind, 2-month studies. Improvement in symptoms was parallelled by an improvement in health-related quality of life in a nonblind, 6-month trial. Significantly more venous leg ulcers </=10 cm in diameter completely healed with MPFF 500 mg twice daily plus standard management (compression and local treatment) for 2-6 months than with standard management alone or with placebo in a nonblind and a double-blind trial. The addition of MPFF to standard management was cost effective in a retrospective pharmacoeconomic analysis of the 6-month trial. Compared with placebo, the duration and/or intensity of individual symptoms of grade 1 or 2 acute internal haemorrhoids improved significantly with 3 tablets of MPFF 500 mg twice daily for 4 days then 2 tablets of MPFF 500 mg twice daily for 3 days. Two tablets of MPFF 500 mg daily for 60 or 83 days reduced the frequency, duration and/or severity of acute haemorrhoidal symptoms and improved the overall signs and symptoms of chronic (recurrent) haemorrhoids compared with placebo. Compared with a control group, MPFF significantly reduced the risk of secondary bleeding after elective haemorrhoidectomy. In clinical trials, MPFF had a tolerability profile similar to that of placebo; the most frequently reported adverse events were gastrointestinal and autonomic in nature. In conclusion, MPFF is a well established and well tolerated treatment option in patients with CVI, venous ulcers, or acute or chronic internal haemorrhoids. MPFF is indicated as a first-line treatment of oedema and the symptoms of CVI in patients in any stage of the disease. In more advanced disease stages, MPFF may be used in conjunction with sclerotherapy, surgery and/or compression therapy, or as an alternative treatment when surgery is not indicated or is unfeasible. The healing of venous ulcers </=10 cm in diameter is accelerated by the addition of MPFF to standard venous ulcer management. MPFF may reduce the frequency, duration and/or intensity of symptoms of grade 1 or 2 acute internal haemorrhoids, and also the severity of the signs and symptoms of chronic haemorrhoids.

Effectiveness of a unique dihydropyridine (BAYTG 1000) for prevention of laminitis in horses

OBJECTIVE

To determine whether a unique dihydropyridine (BAYTG 1000) would be beneficial in preventing laminitis in horses.

ANIMALS

16 clinically normal adult horses.

PROCEDURE

8 pairs of horses were used in a controlled double-blind study, using sex- and age-matched horses randomly assigned to treatment or control groups. Horses were subjected to carbohydrate overload to induce laminitis. Treated horses were administered BAY TG 1000 (30 mg/kg, PO, q 24 h) for 3 days. Hoof wall surface temperature (HWST) and lameness were recorded at 4-hour intervals. The HWST was adjusted on the basis of time of onset of lameness and evaluated, using a repeated-measures ANOVA. Lameness 8 hours after onset and clinical status 72 hours after onset of lameness were evaluated, using Mann-Whitney procedures.

RESULTS

Analysis revealed that BAYTG 1000 did not decrease the incidence of lameness but significantly ameliorated prodromal hypothermia, lessened the severity of lameness 8 hours after onset of lameness, and improved the clinical status of horses 72 hours after onset of lameness.

CONCLUSION AND CLINICAL RELEVANCE

Results support the conclusion that BAYTG 1000 was protective when used in prevention of laminitis. The drug decreased severity and improved clinical status (recovery) of induced lameness, which was interpreted to mean that the drug's actions were on mechanisms important but secondary to primary causal mechanisms of laminitis. Therefore, drugs that enhance digital perfusion via alteration of rheologic activity may have potential use in the prevention and management of laminitis in horses.

Chemistry and pharmacology of the Citrus bioflavonoid hesperidin

Hesperidin, a bioflavonoid, is an abundant and inexpensive by-product of Citrus cultivation. A deficiency of this substance in the diet has been linked with abnormal capillary leakiness as well as pain in the extremities causing aches, weakness and night leg cramps. No signs of toxicity have been observed with the normal intake of hesperidin or related compounds. Both hesperidin and its aglycone hesperetin have been reported to possess a wide range of pharmacological properties. This paper reviews various aspects of hesperidin and its related compounds, including their occurrence, physical and chemical properties, analysis, pharmacokinetics, safety and toxicity and the marketed products available. A special emphasis has been laid on the pharmacological properties and medicinal uses of these compounds.

Effects of flavonols on the generation of superoxide anion radicals by xanthine oxidase and stimulated neutrophils

The effects of three aglycon flavonols (myricetin, quercetin, and kaempferol) and the natural glycoside rutin on superoxide anion radical generating systems were investigated. Quercetin, myricetin, and kaempferol inhibited the formation of uric acid from xanthine by xanthine oxidase, while rutin was ineffective. The generation of superoxide anion radicals by this system was determined by either reduction of cytochrome c or Pholasin luminescence. A scavenging of superoxide was only observed for myricetin and to a small extent for rutin. All flavonols tested inhibited the Pholasin luminescence of fMet-Leu-Phe-stimulated neutrophils. Rutin influenced the oxidative burst of neutrophils in the same way as wortmannin and LY294002, two inhibitors of the phosphoinositide 3-kinase gamma. Indeed, rutin inhibited the activity of this enzyme, whereas the three other flavonols showed no effect. Thus, an inhibition of enzymes involved in signaling rather than a scavenging of superoxide anion radicals dominates in fMet-Leu-Phe-stimulated neutrophils exposed to flavonols.

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

Renal ischemia--reperfusion injury: an inescapable event affecting kidney transplantation outcome

Ischemia--reperfusion (I-R) injury has been shown to be a common cause of late and irreversible complications during a variety of standard medical and surgical procedures. The pathogenesis of events which follow the I-R involves both injured endothelium and activated leukocytes and their interaction. In kidney transplantation, an I-R injury occurs in situations such as graft harvesting, cold storage and surgery. Clinical consequences of I-R injury have been considered to be delayed graft function and acute rejection in the short term and chronic rejection late after transplantation. Here we focused on current knowledge of pathophysiology of renal I-R injury in kidney transplantation and on possibilities of experimental therapy.