Therapeutic potential of flavonoids in the treatment of chronic venous insufficiency.

Chronic venous insufficiency (CVI) is a common disorder associated with a variety of symptoms in later disease stages; despite the high prevalence of this pathology, suitable pharmaceutical therapies have not been explored to date. In this context, it was recently reported that a chronic increase in venous wall stress or biomechanical stretch is sufficient to cause development of varicose veins. Recent evidence demonstrate that flavonoids are natural substances that convey the circulatory system functionality, playing a key role in blood flow. Particularly, troxerutin, diosmin and horse chestnut extract, appear protective for the management of vascular diseases. The aim of the present study was to evaluate the effect of a flavonoid compound, containing troxerutin, diosmin and horse chestnut extract on in vitro model on HUVECs cells, due to its production of vasculoregulatory and vasculotropic molecules, on an ex-vivo model on mesenteric vessel contraction, to regularize mesenteric microcirculation and on in vivo model of CVI-induced by saphene vein ligation. Furthermore, the flavonoid compound capacity of extensibility and compatibility with peripheral veins was investigated through a tissue block culture study. The degree of absorption, the contractile venous activity, the histological analysis, the immunoistochemical and immunofluorescence evaluation for VEGF and CD34 were performed, together with inflammatory mediators dosage. For the first time, this research revealed the therapeutic potential of a compound, enriched with flavonoids, to be a supportive treatment, suitable to reduce varicose vein pathophysiology and to regularize venous tone.

Successful intravenous administration of argatroban in the management of heparin-resistant and surgery-resistant mesenteric vein thrombosis.

A 78-year-old woman visited the emergency department with complaints of progressively worsening abdominal pain for a week. Nausea and vomiting started at the time of the visit. An abdominal contrast-enhanced CT (CECT) revealed a filling defect of portal vein, splenic vein and superior mesenteric vein (SMV) which was diagnosed as portal vein and mesenteric venous thrombosis (MVT). Intravenous administration of unfractionated heparin was initiated. However, her symptoms did not improve, and she underwent surgical thrombectomy on the second day of hospitalisation. On the sixth day, CECT revealed the recurrence of thrombi in the portal vein, SMV and along the central venous catheters. We switched heparin to argatroban on the eighth day. After administering argatroban, CECT revealed that the thrombi had almost disappeared by the 40th day. In this case, argatroban was considered effective for heparin-resistant and surgery-resistant portal vein and MVT.

The anthelmintic praziquantel is a human serotoninergic G-protein-coupled receptor ligand.

Schistosomiasis is a debilitating tropical disease caused by infection with parasitic blood flukes. Approximately 260 million people are infected worldwide, underscoring the clinical and socioeconomic impact of this chronic infection. Schistosomiasis is treated with the drug praziquantel (PZQ), which has proved the therapeutic mainstay for over three decades of clinical use. However, the molecular target(s) of PZQ remain undefined. Here we identify a molecular target for the antischistosomal eutomer - (R)-PZQ - which functions as a partial agonist of the human serotoninergic 5HT2B receptor. (R)-PZQ modulation of serotoninergic signaling occurs over a concentration range sufficient to regulate vascular tone of the mesenteric blood vessels where the adult parasites reside within their host. These data establish (R)-PZQ as a G-protein-coupled receptor ligand and suggest that the efficacy of this clinically important anthelmintic is supported by a broad, cross species polypharmacology with PZQ modulating signaling events in both host and parasite.

Neovestitol, an isoflavonoid isolated from Brazilian red propolis, reduces acute and chronic inflammation: involvement of nitric oxide and IL-6.

Isoflavonoids have been largely studied due to their distinct biological activities identified thus far. Herein, we evaluated the activity of neovestitol, an isoflavonoid isolated from Brazilian red propolis, in acute and chronic inflammation. As for acute inflammation, we found that neovestitol reduced neutrophil migration, leukocyte rolling and adhesion, as well as expression of ICAM-1 in the mesenteric microcirculation during lipopolysaccharide-induced acute peritonitis. No changes were observed in the levels of TNF-α, CXCL1/KC and CXCL2/MIP-2 upon pretreatment with neovestitol. The administration of an inducible nitric oxide synthase (iNOS) inhibitor abolished the inhibitory effects of neovestitol in neutrophil migration and ICAM-1 expression. Nitrite levels increased upon treatment with neovestitol. No effects of neovestitol were observed on the chemotaxis of neutrophils in vitro. As for chronic inflammation, neovestitol also reduced the clinical score and joint damage in a collagen-induced arthritis model. There was no change in the frequency of IL-17-producing TCD4+ cells. In addition, pretreatment with neovestitol reduced the levels of IL-6. These results demonstrate a potential anti-inflammatory activity of neovestitol, which may be useful for therapeutic purposes and/or as a nutraceutical.

Total dosage of gardenia fruit used by patients with mesenteric phlebosclerosis.

BACKGROUND: Mesenteric phlebosclerosis (MP) is a disease characterized by fibrotic change or calcification of the mesenteric vein. Recently, there has been an increase in case reports of MP related to herbal medicine usage. Long-term intake of gardenia fruit (GF) is suspected as a possible cause. However, many GF users do not develop this disease and the association between GF and MP remains unclear. In this study, we investigated for the first time the dosage of GF used by patients with and without MP. METHODS: We used a medical chart review study design to assess the association between GF and MP. We reviewed patients with a history of intake of herbal medicines containing GF. Among these patients, we selected patients who were examined by colonoscopy and abdominal plain computed tomography (CT). We investigated the findings of colonoscopy, CT scan and histological examination. We assessed the total dosages of GF alongside the duration of ambulatory visit, the administration period of herbal medicine containing GF and pre-existing disease in order to compare MP cases and non-MP patients. RESULTS: Ten MP cases and 42 non-MP patients were analyzed. We summarized clinical findings of MP cases. All MP cases used more GF than non-MP patients and were administered more than approximately 5,000 grams of GF in cumulative dosage. CONCLUSIONS: This study indicated that excessive intake of GF contributes to and/or accelerates the development of MP suggesting that long-term usage of GF in excessive amounts increases the risk of MP.

Clinical Search for Undiagnosed Mesenteric Phlebosclerosis at Outpatient Departments Specializing in Herbal (Kampo) Medicine.

OBJECTIVE: Mesenteric phlebosclerosis (MP) is a disease characterized by calcification of the mesenteric vein, which causes chronic mesenteric ischemia. Recently, the long-term intake of gardenia fruit ('Sanshishi' in Japanese) has been attracting attention as a possible cause. Usually, only advanced, severe MP cases get reported. However, we suspected that some latent cases of this disease may exist. We performed this study in order to determine the prediagnostic cases at our outpatient departments of herbal (Kampo) medicine, with particular attention paid to the initial changes, such as any slight color change of the colon, as shown in colonoscopy. METHODS: We recommend colonoscopy and computed tomography (CT) scans for patients with a long-term history of taking herbal medicines containing gardenia fruit. Clinical examinations were performed upon receiving patients' consent from December 2013 to November 2014. RESULTS: Of the 103 patients who took gardenia fruit long-term, 29 agreed to be checked for MP. 14 patients underwent colonoscopy. Four patients were confirmed to have MP due to the presence of fibrotic deposition of the colonic membrane on histological inspection. Twenty-one patients underwent abdominal CT screening. Characteristic calcification of the mesenteric vein was observed on CT scans in 2 patients. All 4 MP patients took Kampo formulas containing gardenia fruit for more than 6.8 years. The other patients did not develop MP, despite long-term gardenia fruit intake. CONCLUSION: We detected the latent and undiagnosed MP cases. All diagnoses were made while paying careful attention to any slight changes in colonoscopy and CT scans.

Mesenteric vasculitis after G-CSF administration in a severe neutropenic patient with systemic lupus erythematosus.

Granulocyte colony-stimulating factor (G-CSF) is commonly used with neutropenic patients to accelerate recovery. G-CSF is a hematopoietic cytokine that regulates the proliferation and differentiation of neutrophil precursors, and is known as a safe and effective treatment for chemotherapy-induced neutropenia. However, we encountered a case in which a patient with systemic lupus erythematosus (SLE) developed mesenteric vasculitis after G-CSF administration. The patient was a 36-year-old female admitted with fever, arthralgia, and generalized erythematous rash. Despite symptomatic improvement with a high-dose steroid, severe neutropenia persisted for three weeks, precipitating a decision to use G-CSF to enhance recovery. Mesenteric vasculitis developed 15 hours after administration of G-CSF injection. Because the response of immune cells such as neutrophils and T cells is uncontrolled and dysfunctional in patients with lupus, G-CSF therapy should be used with caution.

Effects of ethyl pyruvate on leukocyte-endothelial interactions in the mesenteric microcirculation during early sepsis treatment

OBJECTIVES: Experimental studies on sepsis have demonstrated that ethyl pyruvate is endowed with antioxidant and anti-inflammatory properties. This study aimed to investigate the effects of ethyl pyruvate on leukocyte-endothelial interactions in the mesenteric microcirculation in a live Escherichia coli-induced sepsis model in rats. METHODS: Male Wistar rats were administered an intravenous suspension of E. coli bacteria or were subjected to a sham procedure. Three hours after bacterial infusion, the rats were randomized into the following groups: a control group without treatment, a group treated with lactated Ringer’s solution (4 mL/kg, i.v.), and a group treated with lactated Ringer’s solution (4 mL/kg, i.v.) plus ethyl pyruvate (50 mg/kg). At 24 h after bacterial infusion, leukocyte-endothelial interactions were investigated using intravital microscopy, and the expression of P-selectin and intercellular adhesion molecule-1 was evaluated via immunohistochemistry. White blood cell and platelet counts were also determined at baseline and 3 h and 24 h after E. coli inoculation. RESULTS: The non-treated and lactated Ringer’s solution-treated groups exhibited increases in the numbers of rolling leukocytes (∼2.5-fold increase), adherent cells (∼3.0-fold), and migrated cells (∼3.5-fold) compared with the sham group. In contrast, treatment with Ringer’s ethyl pyruvate solution reduced the numbers of rolling, adherent and migrated leukocytes to the levels observed in the sham group. Additionally, the expression of P-selectin and intercellular adhesion molecule-1 was significantly increased on mesenteric microvessels in the non-treated group compared with the sham group (p<0.001). The expression of both adhesion molecules was reduced in the other groups, with ethyl pyruvate being more effective than lactated Ringer’s solution. Infusion of bacteria caused significant leukopenia (3 h), followed ...

Initial transcatheter thrombolysis for acute superior mesenteric venous thrombosis.

AIM: To determine the optimal initial treatment modality for acute superior mesenteric vein thrombosis (ASMVT) in patients with circumscribed peritonitis. METHODS: A retrospective review was made of the Vascular Surgery Department's medical records to identify adult patients (≥ 18 years old) presenting with circumscribed peritonitis and diagnosed with ASMVT by imaging or endoscopic examination. Patients were selected from the time period between October 2009 and October 2012 to assess the overall performance of a new first-line treatment policy implemented in May 2011 for patients with circumscribed peritonitis, which recommends transcatheter thrombolysis with local anticoagulation and endovascular mechanical thrombectomy. Of the 25 patients selected for study inclusion, 12 had undergone emergency surgical exploration (group 1) and 13 had undergone the initial catheter-directed thrombolysis (group 2). Data extracted from each patient's records for statistical analyses included method of diagnosis, symptoms, etiology and risk factors, thrombus location, initial management, morbidity, mortality, duration and total cost of hospitalization (in Renminbi, RMB), secondary operation, total length of bowel resection, duration of and findings in follow-up, and death/survival. RESULTS: The two treatment groups showed similar rates of morbidity, 30-d mortality, and 1-year survival, as well as similar demographic characteristics, etiology or risk factors, computed tomography characteristics, symptoms, findings of blood testing at admission, complications, secondary operations, and follow-up outcomes. In contrast, the patients who received the initial non-operative treatment of transcatheter thrombolysis had significantly shorter durations of admission to symptom elimination (group 1: 18.25 ± 7.69 d vs group 2: 7.23 ± 2.42 d) and hospital stay (43.00 ± 13.77 d vs 20.46 ± 6.59 d), and early enteral or oral nutrition restoration (20.50 ± 5.13 d vs 8.92 ± 1.89 d), as well as significantly less total length of bowel resection (170.83 ± 61.27 cm vs 29.23 ± 50.24 cm) and lower total cost (200020.4 ± 91505.62 RMB vs 72785.6 ± 21828.16 RMB) (P < 0.05 for all). Statistical analyses suggested that initial transcatheter thrombolysis is correlated with quicker resolution of the thrombus, earlier improvement of symptoms, stimulation of collateral vessel development, reversal of intestinal ischemia, receipt of localizing bowel resection to prevent short bowel syndrome, shorter hospitalization, and lower overall cost of treatment. CONCLUSION: For ASMVT patients with circumscribed peritonitis, early diagnosis is key to survival, and non-operative transcatheter thrombolysis is feasible and effective as an initial treatment.

Protective mechanisms of adenosine 5'-monophosphate in platelet activation and thrombus formation.

Platelet activation is relevant to a variety of acute thrombotic events. We sought to examine adenosine 5'-monophosphate (AMP) mechanisms of action in preventing platelet activation, thrombus formation and platelet-related inflammatory response. We assessed the effect of AMP on 1) P-selectin expression and GPIIb/IIIa activation by flow cytometry; 2) Platelet aggregation and ATP secretion induced by ADP, collagen, TRAP-6, convulxin and thrombin; 3) Platelet rolling and firm adhesion, and platelet-leukocyte interactions under flow-controlled conditions; and, 4) Platelet cAMP levels, sP-selectin, sCD40L, IL-1ß, TGF-ß1 and CCL5 release, PDE3A activity and PKA phosphorylation. The effect of AMP on in vivo thrombus formation was also evaluated in a murine model. The AMP docking with respect to A2 adenosine receptor was determined by homology. AMP concentration-dependently (0.1 to 3 mmol/l) inhibited P-selectin expression and GPIIb/IIIa activation, platelet secretion and aggregation induced by ADP, collagen, TRAP-6 and convulxin, and diminished platelet rolling and firm adhesion. Furthermore, AMP induced a marked increase in the rolling speed of leukocytes retained on the platelet surface. At these concentrations AMP significantly decreased inflammatory mediator from platelet, increased intraplatelet cAMP levels and inhibited PDE3A activity. Interestingly, SQ22536, ZM241385 and SCH58261 attenuated the antiplatelet effect of AMP. Docking experiments revealed that AMP had the same orientation that adenosine inside the A2 adenosine receptor binding pocket. These in vitro antithrombotic properties were further supported in an in vivo model of thrombosis. Considering the successful use of combined antiplatelet therapy, AMP may be further developed as a novel antiplatelet agent.

Impaired function of prejunctional adenosine A1 receptors expressed by perivascular sympathetic nerves in DOCA-salt hypertensive rats.

Increased sympathetic nervous system activity contributes to deoxycorticosterone acetate (DOCA)-salt hypertension in rats. ATP and norepinephrine (NE) are coreleased from perivascular sympathetic nerves. NE acts at prejunctional α2-adrenergic receptors (α2ARs) to inhibit NE release, and α2AR function is impaired in DOCA-salt rats. Adenosine, an enzymatic ATP degradation product, acts at prejunctional A1 adenosine receptors (A1Rs) to inhibit NE release. We tested the hypothesis that prejunctional A1R function is impaired in sympathetic nerves supplying mesenteric arteries (MAs) and veins (MVs) of DOCA-salt rats. Electrically evoked NE release and constrictions of blood vessels were studied in vitro with use of amperometry to measure NE oxidation currents and video microscopy, respectively. Immunohistochemical methods were used to localize tyrosine hydroxylase (TH) and A1Rs in perivascular sympathetic nerves. TH and A1Rs colocalized to perivascular sympathetic nerves. Adenosine and N(6)-cyclopentyl-adenosine (CPA, A1R agonist) constricted MVs but not MAs. Adenosine and CPA (0.001-10 µM) inhibited neurogenic constrictions and NE release in MAs and MVs. DOCA-salt arteries were resistant to adenosine and CPA-mediated inhibition of NE release and constriction. The A2A adenosine receptor agonist CGS21680 (C23H29N7O6.HCl.xH2O) (0.001-0.1 µM) did not alter NE oxidation currents. We conclude that there are prejunctional A1Rs in arteries and both pre- and postjunctional A1Rs in veins; thus, adenosine selectively constricts the veins. Prejunctional A1R function is impaired in arteries, but not veins, from DOCA-salt rats. Sympathetic autoreceptor dysfunction is not specific to α2ARs, but there is a more general disruption of prejunctional mechanisms controlling sympathetic neurotransmitter release in DOCA-salt hypertension.

The role of endothelium in the vasorelaxant effects of the essential oil of Ocimum gratissimum in aorta and mesenteric vascular bed of rats.

This study investigated the endothelium-dependent vasorelaxant effects of the essential oil of Ocimum gratissimum (EOOG) in aortas and mesenteric vascular beds isolated from rats. EOOG (3-300 µg/mL) relaxed the tonic contractions induced by phenylephrine (0.1 µmol/L) in isolated aortas in a concentration-dependent manner in both endothelium-containing and endothelium-denuded preparations. This effect was partially reversed by L-NAME (100 µmol/L) but not by indomethacin (10 µmol/L) or TEA (5 mmol/L). In mesenteric vascular beds, bolus injections of EOOG (30, 50, 100, and 300 ng) decreased the perfusion pressure induced by noradrenaline (6 µmol/L) in endothelium-intact preparations but not in those treated with deoxycholate. L-NAME (300 µmol/L) but not TEA (1 mmol/L) or indomethacin (3 µmol/L) significantly reduced the vasodilatory response to EOOG at all of the doses tested. Our data showed that EOOG exerts a dose-dependent vasodilatory response in the resistance blood vessels of rat mesenteric vascular beds and in the capacitance blood vessel, the rat aorta. This action is completely dependent on endothelial nitric oxide (NO) release in the mesenteric vascular beds but only partially dependent on NO in the aorta. These novel effects of EOOG highlight interesting differences between resistance and capacitance blood vessels.

Functional crosstalk of prejunctional receptors on the modulation of noradrenaline release in mesenteric vessels: A differential study of artery and vein.

The role of angiotensin II receptors, bradykinin receptors and ß-adrenoceptors in the modulation of noradrenaline release and the influence of α(2)-autoinhibition in these effects was investigated in the mesenteric artery and vein. Rings of mesenteric vessels of male Wistar rats were labelled with [(3)H]-noradrenaline and the effects of modulators on tritium overflow evoked by 100 pulses at 2Hz (marked α(2)-autoinhibition) and by 20 pulses at 50Hz or 100 pulses at 2Hz plus yohimbine (1µM; reduced α(2)-autoinhibition) were evaluated. Angiotensin II and bradykinin enhanced noradrenaline release evoked by 100 pulses at 2Hz, in a concentration-dependent manner, in both vessels. These effects were attenuated under conditions of reduced α(2)-autoinhibition. The attenuation was partially reversed by activation of adenosine A(1) receptors in both vessels and by activation of P2Y receptors in the vein. Isoprenaline and the selective ß(2)-adrenoceptor agonist formoterol enhanced tritium overflow independently of α(2)-autoinhibition in the vein. In the artery, the enhancement by formoterol was only observed under reduced α(2)-autoinhibition. Pharmacological characterization of the ß-adrenoceptors indicated that in the artery the effect of isoprenaline was mediated by the ß(1)-subtype under marked α(2)-autoinhibition and by the ß(2)-subtype under reduced α(2)-autoinhibition whereas in the vein the effect was independent of α(2)-autoinhibition. The results indicate that α(2)-autoinhibition is a key determinant of the magnitude of facilitation caused by angiotensin II and bradykinin in both types of mesenteric vessels and regulates the effects mediated by ß(1)-and ß(2)-adrenoceptors which co-exist in the artery.

Inhibition of canonical Wnt signaling increases microvascular hemorrhaging and venular remodeling in adult rats.

OBJECTIVE: The canonical Wnt signaling pathway, heavily studied in development and cancer, has recently been implicated in microvascular growth with the use of developmental and in vitro models. To date, however, no study exists showing the effects of perturbing the canonical Wnt pathway in a complete microvascular network undergoing physiological remodeling in vivo. Our objective was to investigate the effects of canonical Wnt inhibition on the microvascular remodeling of adult rats. METHODS: Canonical Wnt inhibitor DKK-1, Wnt inhibitor sFRP-1, BSA or saline was superfused onto the exteriorized mesenteric windows of 300 g adult female Sprague-Dawley rats for 20 minutes. Three days following surgery, mesenteric windows were imaged intravitally and harvested for immunofluorescence staining with smooth muscle alpha-actin and BRDU. RESULTS: We observed prominent differences in the response of the mesenteric microvasculature amongst the various treatment groups. Significant increases in hemorrhage area, vascular density, and draining vessel diameter were observed in windows treated with Wnt inhibitors as compared to control-treated windows. Additionally, confocal imaging analysis showed significant increases in proliferating cells as well as evidence of proliferating smooth muscle cells along venules. CONCLUSIONS: Together, our results suggest that canonical Wnt inhibition plays an important role in microvascular remodeling, specifically venular remodeling.

Horse chestnut extract contracts bovine vessels and affects human platelet aggregation through 5-HT(2A) receptors: an in vitro study.

Extract from seeds and bark of horse chestnut (Aesculus hippocastanum L) is used as an herbal medicine against chronic venous insufficiency. The effect and mechanism of action on veins, arteries, and platelets are not fully understood. The aim of this study was to investigate the effects and mechanisms of action of horse chestnut on the contraction of bovine mesenteric veins and arteries, and human platelet aggregation. Contraction studies showed that horse chestnut extract dose-dependently contracted both veins and arteries, with the veins being the most sensitive. Contraction of both veins and arteries were significantly inhibited by the 5-HT(2A) receptor antagonist ketanserin. No effect on contraction was seen with the cyclooxygenase inhibitor indomethacin, the alpha(1) receptor antagonist prazosin or the angiotensin AT(1) receptor antagonist saralasin neither in veins nor arteries. ADP-induced human platelet aggregation was significantly reduced by horse chestnut. A further reduction was seen with the extract in the presence of ketanserin. In conclusion, horse chestnut contraction of both veins and arteries is, at least partly, mediated through 5-HT(2A) receptors. Human platelet aggregation is reduced by horse chestnut. The clinical importance of these findings concerning clinical use, possible adverse effects, and drug interactions remains to be investigated.

Glutamine and alanyl-glutamine dipeptide reduce mesenteric plasma extravasation, leukocyte adhesion and tumor necrosis factor-α (TNF-α) release during experimental endotoxemia.

Glutamine (GLN) appears to be an essential nutrient during organism development and critical illness. The aim of our study was to evaluate the effects of GLN and its generic preparation alanyl-glutamine-dipeptide (DIP) on the microcirculation in endotoxemia in rats and its effects on tonus or aortal rings in vitro. Male Lewis rats (n=40) were separated in 4 groups. Group 1 (CON) served as healthy control group while the other groups received an endotoxin bolus i.v. (5 mg/kg lipopolysaccharide, LPS i.v.). In group 3 (LPS+GLN) 0.75 g/kg-1 GLN i.v. before LPS challenge was administered. In group 4 (LPS+DIP) DIP containing 0.75 g/kg GLN was given. Leukocyte-endothelial interactions and mesenteric plasma extravasation were determined at 0, 1 and 2 hours during the experiment by intravital fluorescence microscopy (IVM). Cytokine release (TNF-alpha, IL-1 beta, IL-6, IL-10) was measured by ELISA. GLN treatment reduced leukocyte adherence (-49.7% vs. LPS group, p<0.05) and plasma extravasation (-12.3% vs. LPS group, p<0.05) significantly during endotoxemia compared to untreated LPS animals. In group 4 (DIP+LPS), a decrease of leukocyte adherence (-56.0%) and mesenteric plasma extravasation (-18.8% vs. LPS group, p<0.05) was also found. TNF-alpha levels were reduced in both GLN and DIP (p<0.05). In vitro experiments demonstrated that glutamine agents could attenuate the response to contracting agents in presence of the vascular endothelium, implying nitric oxide pathway. In vivo, GLN as well as DIP pre-treatment diminish the detrimental impact of endotoxemia on the mesenteric microcirculation and the TNF-alpha release, the effects whose clinical importance should be further examined.

Mast cell inhibition by ketotifen reduces splanchnic inflammatory response in a portal hypertension model in rats.

Experimental early prehepatic portal hypertension induces an inflammatory exudative response, including an increased infiltration of the intestinal mucosa and the mesenteric lymph nodes by mast cells and a dilation and tortuosity of the branches of the superior mesenteric vein. The aim of this study is to verify that the prophylactic administration of Ketotifen, a stabilizing drug for mast cells, reduces the consequence of splanchnic inflammatory response in prehepatic portal hypertension. Male Wistar rats were used: Sham-operated and with Triple Partial Portal Vein Ligation, which were subcutaneously administered poly(lactide-co-glycolide) acid microspheres with vehicle 24h before the intervention and SO and rats with Triple Partial Portal Vein Ligation, which were administered Ketotifen-loaded microspheres. Around 48h after surgery, the portal pressure was measured; the levels of chymase (Rat Mast Cell Protease-II) were assayed in the superior mesenteric lymph complex and granulated and degranulated mast cells in the ileum and cecum were quantified. Prophylactic administration of Ketotifen reduced portal pressure, the incidence of dilation and tortuosity of the superior mesenteric vein branches, the amount of Rat Mast Cell Protease-II in the superior mesenteric lymph complex and the number of activated mast cells in the cecum of rats with portal hypertension. In summary, the administration of Ketotifen reduces early splanchnic inflammatory reaction in the rat with prehepatic portal hypertension.

Roflumilast inhibits leukocyte-endothelial cell interactions, expression of adhesion molecules and microvascular permeability.

BACKGROUND AND PURPOSE: The present study addressed the effects of the investigational PDE4 inhibitor roflumilast on leukocyte-endothelial cell interactions and endothelial permeability in vivo and in vitro. EXPERIMENTAL APPROACH: In vivo, intravital video-microscopy was used to determine effects of roflumilast p.o. on leukocyte-endothelial cell interactions and microvascular permeability in rat mesenteric venules. In vitro, the effects of roflumilast N-oxide, the active metabolite of roflumilast in humans, and other PDE4 inhibitors on neutrophil adhesion to tumour necrosis factor alpha (TNFalpha)-activated human umbilical vein endothelial cells (HUVEC), E-selectin expression and thrombin-induced endothelial permeability was evaluated. Flow cytometry was used to determine the effect of roflumilast on N-formyl-methionyl-leucyl-phenylalanine (fMLP)-induced CD11b upregulation on human neutrophils. KEY RESULTS: In vivo, roflumilast, given 1 h before lipopolysaccharide (LPS), dose-dependently reduced leukocyte-endothelial cell interactions in rat mesenteric postcapillary venules. It also diminished histamine-induced microvascular permeability. Immunohistochemical analyses revealed that roflumilast prevented LPS-induced endothelial P- and E-selectin expression. In vitro, roflumilast N-oxide concentration-dependently suppressed neutrophil adhesion to TNFalpha-activated HUVEC and CD11b expression on fMLP-stimulated neutrophils. It also reduced TNFalpha-induced E-selectin expression on HUVEC, when PDE3 activity was blocked. HUVEC permeability elicited by thrombin was concentration-dependently suppressed by roflumilast N-oxide. While roflumilast N-oxide was as potent as roflumilast at inhibiting stimulated endothelial cell and neutrophil functions, both compounds were significantly more potent than the structurally unrelated PDE4 inhibitors, rolipram or cilomilast. CONCLUSIONS AND IMPLICATIONS: These findings further support earlier observations on the inhibition of inflammatory cell influx and protein extravasation by roflumilast in vivo.

EGCG, a green tea polyphenol, improves endothelial function and insulin sensitivity, reduces blood pressure, and protects against myocardial I/R injury in SHR.

Epigallocatechin gallate (EGCG), a bioactive polyphenol in green tea, may augment metabolic and vascular actions of insulin. Therefore, we investigated effects of EGCG treatment to simultaneously improve cardiovascular and metabolic function in spontaneously hypertensive rats (SHR; model of metabolic syndrome with hypertension, insulin resistance, and overweight). In acute studies, EGCG (1-100 microM) elicited dose-dependent vasodilation in mesenteric vascular beds (MVB) isolated from SHR ex vivo that was inhibitable by N(omega)-nitro-L-arginine methyl ester (L-NAME; nitric oxide synthase antagonist) or wortmannin [phosphatidylinositol (PI) 3-kinase inhibitor]. In chronic studies, 9-wk-old SHR were treated by gavage for 3 wk with EGCG (200 mg.kg(-1).day(-1)), enalapril (30 mg.kg(-1).day(-1)), or vehicle. A separate group of SHR receiving L-NAME (80 mg/l in drinking water) was treated for 3 wk with either EGCG or vehicle. Vasodilator actions of insulin were significantly improved in MVB from EGCG- or enalapril-treated SHR (when compared with vehicle-treated SHR). Both EGCG and enalapril therapy significantly lowered systolic blood pressure (SBP) in SHR. EGCG therapy of SHR significantly reduced infarct size and improved cardiac function in Langendorff-perfused hearts exposed to ischemia-reperfusion (I/R) injury. In SHR given L-NAME, beneficial effects of EGCG on SBP and I/R were not observed. Both enalapril and EGCG treatment of SHR improved insulin sensitivity and raised plasma adiponectin levels. We conclude that acute actions of EGCG to stimulate production of nitric oxide from endothelium using PI 3-kinase-dependent pathways may explain, in part, beneficial effects of EGCG therapy to simultaneously improve metabolic and cardiovascular pathophysiology in SHR. These findings may be relevant to understanding potential benefits of green tea consumption in patients with the metabolic syndrome.

Epidermal growth factor receptor tyrosine kinase-mediated signalling contributes to diabetes-induced vascular dysfunction in the mesenteric bed.

In order to characterize the roles of tyrosine kinases (TKs) and epidermal growth factor receptor (EGFR) in diabetes-induced vascular dysfunction, we investigated the ability of a chronic administration of genistein, a broad-spectrum inhibitor of TKs and AG1478, a specific inhibitor of EGFR TK activity to modulate the altered vasoreactivity of the perfused mesenteric bed to common vasoconstrictors and vasodilators in streptozotocin (STZ)-induced diabetes in rats. The vasoconstrictor responses induced by norepinephrine (NE), endothelin-1 (ET-1) and angiotensin II (Ang II), were significantly increased, whereas vasodilator responses to carbachol and histamine were significantly reduced in the perfused mesenteric bed of STZ-induced diabetic rats in comparison with healthy rats. Treatment of diabetic animals with genistein or AG1478 produced a significant normalization of the altered agonist-induced vasoconstrictor and vasodilator responses without affecting blood glucose levels. In contrast, neither inhibitor had any effect on the vascular responsiveness of control (nondiabetic) animals. Treatment of diabetic animals with diadzein, an inactive analogue of genistein, did not affect the vasoconstrictor and vasodilator responses in control or diabetic animals. Phosphorylated EGFR levels were markedly raised in the mesenteric bed from diabetic animals and were normalized upon treatment with AG1478 or genistein. These data suggest that activation of TK-mediated pathways, including EGFR TK signalling are involved in the development of diabetic vascular dysfunction.