Sesamol regulates plasminogen activator gene expression in cultured endothelial cells: a potential effect on the fibrinolytic system

Role of Substance P-Dependent Chemotactic Signaling in Postoperative Adhesion Formation

BACKGROUND

Postoperative adhesions are a potentially life-threatening complication of abdominal surgery. We previously showed that substance P (SP), acting through the neurokinin-1 receptor (NK-1R), is an important early mediator of adhesiogenesis through its regulation of the tissue plasminogen activator/plasminogen activator inhibitor-1 (PAI-1) fibrinolytic system. SP also mediates neurogenic inflammation by recruiting inflammatory leukocytes, such as neutrophils and macrophages. Our objective was to determine the role of SP-dependent chemotactic recruitment of these inflammatory cells through the CXCR2 in postsurgical adhesion formation.

MATERIALS AND METHODS

A mouse cecal cauterization model was used to generate intra-abdominal adhesions. Protein and mRNA levels of the chemokines CXCL1 and CXCL2 and their receptor CXCR2 were measured at 3 h and 6 h after surgery in peritoneal tissue and in peritoneal lavages in response to antagonists for the SP receptor and CXCR2, and in IFN-γ knockout mice.

RESULTS

Postsurgical adhesion formation was inhibited by both an antagonist to NK-1R and an antagonist to CXCR2. Expression levels of neutrophil chemokines and CXCR2 in peritoneal tissue peaked 3-6 h after surgery and partially depended on SP and IFN-γ, one of its downstream mediators. An NK-1R antagonist inhibited SP-mediated increases in the expression of the PAI-1 inhibitory component of the fibrinolytic system, but the CXCR2 antagonist had no effect.

CONCLUSIONS

Postsurgical adhesiogenesis involves upregulation of chemokine signaling that is partially SP- and IFN-γ-dependent. However, the adhesiogenic properties of chemokine signaling are not mediated through the inhibition of fibrinolysis with PAI-1, as was previously shown for SP.

Computationally Designed Sesamol Derivatives Proposed as Potent Antioxidants

Oxidative stress has been recognized to play an important role in several diseases, such as Parkinson's and Alzheimer's disease, which justifies the beneficial effects of antioxidants in ameliorating the deleterious effects of these health disorders. Sesamol, in particular, has been investigated for the treatment of several conditions because of its antioxidant properties. This article reports a rational computational design of new sesamol derivatives. They were constructed by adding four functional groups (-OH, -NH2, -COOH, and -SH) in three different positions of the sesamol molecular framework. A total of 50 derivatives between mono-, di-, and trisubstituted compounds were obtained. All the derivatives were evaluated and compared with a reference set of commercial neuroprotective drugs. The estimated properties are absorption, distribution, metabolism, excretion, toxicity, and synthetic accessibility. Selection and elimination scores were used to choose a first set of promising candidates. Acid-based properties and reactivity indexes were then estimated using the density functional theory. Four sesamol derivatives were finally selected, which are hypothesized to be potent antioxidants, even better than sesamol and Trolox for that purpose.

Medicinal plants with antithrombotic property in Persian medicine: a mechanistic review

Thrombosis is one of the major causes of morbidity and mortality in a wide range of vessels diseases. Due to the high prevalence of thromboembolic disorders investigations are being carried out on new antithrombotic agents with limited adverse side effects in which herbal medicines are considered as alternative remedies. Persian medicine (PM) as a traditional medicine has a good potential for pharmacotherapy based on its own principles and development of drugs via investigating PM literature. In PM manuscripts there are some concepts that express the management of blood clots and antithrombotic properties. This study reviewed the pharmacological effects of medicinal plants mentioned in PM literature for blood clot management in light of current knowledge. Plants mentioned in PM for management of blood clot belong to 12 families in which Apiaceae, Lamiaceae and Compositae were the most repeated ones. Among the proposed plants Allium sativum, Rosmarinus officinalis, Boswellia serrata, Sesamum indicum, Matricaria chamomilla and Carthamus tinctorius have been the most researched plants in modern antithrombotic studies while for some plants such as Helichrysum stoechas, Dracocephalum kotschi, Carum carvi, Bunium persicum and Lagoecia cuminoides no evidence could be found. One of the interesting notes in clot management in PM texts was introducing the target organ for some of the recommended herbs like Carum carvi and Bunium persicum for dissolving blood clot in stomach and Commiphora mukul for thrombosed hemorrhoid. It seems review of PM recommendations can help to design future researches for antithrombotic drugs discovering with more effectiveness and safety.

Is Sesamol Effective in Corneal Neovascularization?

OBJECTIVES

To evaluate the effects of topically and subconjunctivally administered sesamol on experimentally induced corneal neovascularization in rats.

METHODS

Fifty-six right eyes of 56 Wistar Albino rats were chemically cauterized to induce corneal neovascularization in this experimental and comparative study. The subjects were divided into eight groups: topical sesamol (group 1), subconjunctival sesamol (group 2), topical bevacizumab (group 3), subconjunctival bevacizumab (group 4), topical bevacizumab+ sesamol (group 5), subconjunctival bevacizumab+ sesamol (group 6), topical Tween 80 (group 7), and control (group 8). The amount of subconjunctivally injected sesamol and bevacizumab was 1.25 mg each. Topical groups were administered 10 mg/mL drops twice daily. The control group was left untreated. To evaluate the degree of corneal neovascularization, digital photographs and corneal sections stained with hematoxylin-eosin and CD31 were used.

RESULTS

When photographs of neovascularization areas were examined, all treatment groups showed statistically significant differences when compared with the control group (P<0.001). Topical sesamol was found to be more effective when compared with subconjunctival sesamol (P=0.003). Topical sesamol+ bevacizumab was found to be more effective when compared with topical bevacizumab (P=0.018). The numbers of new corneal vessels were as follows: 12.28±6.29 in group 1, 36.85±12.8 in group 2, 18.85±7.71 in group 3, 16.85±8.70 in group 4, 19.57±8.56 in group 5, 22.57±7.43 in group 6, 45.00±11.29 in group 7, and 51.16±5.91 in group 8 (P<0.001).

CONCLUSIONS

The outcomes of this study suggest antiangiogenic effects of sesamol. The use of topical sesamol monotherapy or sesamol combined with bevacizumab may be options for the prevention of corneal neovascularization.

The Protective Effect of Sesamol in the Selenite-induced Experimental Cataract Model

Objectives:

To investigate the potential protective effects of sesamol in an experimental cataract model.

Materials and Methods:

Twenty-one Spraque Dawley rat pups were randomly assigned into three groups, seven rats in each. All the rats except for those in the control group were injected subcutaneously with a single dose of sodium selenite on postpartum day 9. On days 10-14, rats in the sham group were intraperitoneally administered 50 mg/kg/day saline solution, while rats in the sesamol group were given 50 mg/kg/day sesamol by the same route. Following cataract grading, the lenses and capsules were extracted and the mean levels of reduced glutathione (GSH), malondialdehyde (MDA), total antioxidant status (TAS) and total oxidant status (TOS) in lens supernatants were biochemically analyzed.

Results:

The control group did not show any development of cataract. It was found that the mean cataract grade in the sesamol group was significantly lower than that of the sham group (p<0.05). The mean GSH level and TAS in the sesamol group were significantly higher than those of the sham group while the mean TOS and MDA level in the sesamol group were significantly lower than those of the sham group (p<0.05).

Conclusion:

Our study shows that sesamol reduces TOS and MDA level and increases TAS and GSH level in the lens and inhibits cataract formation.

A novel role of sesamol in inhibiting NF-κB-mediated signaling in platelet activation

Background

Platelet activation is relevant to a variety of coronary heart diseases. Our previous studies revealed that sesamol possesses potent antiplatelet activity through increasing cyclic AMP formation. Although platelets are anucleated cells, they also express the transcription factor, NF-κB, that may exert non-genomic functions in platelet activation. Therefore, we further investigated the inhibitory roles of sesamol in NF-κB-mediated platelet function.

Methods

Platelet aggregation, Fura 2-AM fluorescence, and immunoblotting analysis were used in this study.

Results

NF-κB signaling events, including IKKβ phosphorylation, IκBα degradation, and p65 phosphorylation, were markedly activated by collagen (1 μg/ml) in washed human platelets, and these signaling events were attenuated by sesamol (2.5~25 μM). Furthermore, SQ22536 and ODQ, inhibitors of adenylate cyclase and guanylate cyclase, respectively, strongly reversed the sesamol (25 μM)-mediated inhibitory effects of IKKβ phosphorylation, IκBα degradation, and p65 phosphorylation stimulated by collagen. The protein kinase A (PKA) inhibitor, H89, also reversed sesamol-mediated inhibition of IκBα degradation. Moreover, BAY11-7082, an NF-κB inhibitor, abolished IκBα degradation, phospholipase C (PLC)γ2 phosphorylation, protein kinase C (PKC) activation, [Ca²⁺]i mobilization, and platelet aggregation stimulated by collagen. Preincubation of platelets with the inhibitors, SQ22536 and H89, both strongly reversed sesamol-mediated inhibition of platelet aggregation and [Ca²⁺]i mobilization.

Conclusions

Sesamol activates cAMP-PKA signaling, followed by inhibition of the NF-κB-PLC-PKC cascade, thereby leading to inhibition of [Ca²⁺]i mobilization and platelet aggregation. Because platelet activation is not only linked to hemostasis, but also has a relevant role in inflammation and metastasis, our data demonstrating that inhibition of NF-κB interferes with platelet function may have a great impact when these types of drugs are considered for the treatment of cancer and various inflammatory diseases.

Potent antiplatelet activity of sesamol in an in vitro and in vivo model: pivotal roles of cyclic AMP and p38 mitogen-activated protein kinase

Sesamol is a potent phenolic antioxidant which possesses antimutagenic, antihepatotoxic and antiaging properties. Platelet activation is relevant to a variety of acute thrombotic events and coronary heart diseases. There have been few studies on the effect of sesamol on platelets. Therefore, the aim of this study was to systematically examine the detailed mechanisms of sesamol in preventing platelet activation in vitro and in vivo. Sesamol (2.5-5 μM) exhibited more potent activity of inhibiting platelet aggregation stimulated by collagen than other agonists. Sesamol inhibited collagen-stimulated platelet activation accompanied by [Ca(2+)](i) mobilization, thromboxane A(2) (TxA(2)) formation, and phospholipase C (PLC)γ2, protein kinase C (PKC) and mitogen-activated protein kinase (MAPK) phosphorylation in washed platelets. Sesamol markedly increased cAMP and cGMP levels, endothelial nitric oxide synthase (eNOS) expression and NO release, as well as vasodilator-stimulated phosphoprotein (VASP) phosphorylation. SQ22536, an inhibitor of adenylate cyclase, markedly reversed the sesamol-mediated inhibitory effects on platelet aggregation and p38 MAPK phosphorylation, and sesamol-mediated stimulatory effects on VASP and eNOS phosphorylation, and NO release. Sesamol also reduced hydroxyl radical (OH(●)) formation in platelets. In an in vivo study, sesamol (5 mg/kg) significantly prolonged platelet plug formation in mice. The most important findings of this study demonstrate for the first time that sesamol possesses potent antiplatelet activity, which may involve activation of the cAMP-eNOS/NO-cGMP pathway, resulting in inhibition of the PLCγ2-PKC-p38 MAPK-TxA(2) cascade, and, finally, inhibition of platelet aggregation. Sesamol treatment may represent a novel approach to lowering the risk of or improving function in thromboembolism-related disorders.

Antioxidant potential of sesamol and its role on radiation-induced DNA damage in whole-body irradiated Swiss albino mice

Sesamol (SM) is a dietary phytochemical present in the processed sesame oil. In this present study we have evaluated the antioxidant potential of SM and its role in the protection of radiation-induced DNA damage in γ-irradiated mice. The antioxidant properties of SM were evaluated by using different in vitro antioxidant assays. SM shows scavenging effect against hydroxyl (OH), superoxide anion (O(2)(-)), nitric oxide, 2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid radical cation (ABTS(+)) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. Our results demonstrate that SM exhibits strong antioxidant property in all the in vitro assays. When mice were exposed to 7 Gy γ-radiations there was an increase in % tail DNA, tail length, tail moment and Olive tail moment in blood lymphocytes. SM (100mg/kg b.wt) pretreatment significantly decreased the % tail DNA, tail length, tail moment and Olive tail moment in irradiated mice lymphocytes. These results suggest that SM protects γ-radiation-induced DNA damage in mice lymphocytes, which may be attributed to its antioxidant property.

Glycosylation of sesamol by cultured plant cells

The glycosylation of sesamol was investigated using cultured cells of Nicotiana tabacum and Eucalyptus perriniana. The cultured suspension cells of N. tabacum converted sesamol into its beta-glucoside (7%) as well as the disaccharide, sesamyl 6-O-(beta-D-glucopyranosyl)-beta-D-glucopyranoside (beta-gentiobioside, 30%). On the other hand, sesamyl 6-O-(alpha-L-rhamnopyranosyl)-beta-D-glucopyranoside (beta-rutinoside, 56%), together with the beta-glucoside (3%), was produced when sesamol was incubated with suspension cells of E. perriniana.

Bioavailability and tissue distribution of sesamol in rat

Sesamol, generally regarded as the main antioxidative component in sesame oil, can be generated from sesamolin by roasting sesame seed or bleaching sesame oil. This paper reports the bioavailability of sesamol in Sprague-Dawley (SD) rats. Biological fluid was sampled following a dose of sesamol of 50 mg/kg by gastric gavage (p.o.) or by intravenous injection. The pharmacokinetic data of sesamol were calculated by noncompartmental model. The tissue distribution of sesamol (p.o., 100 mg/kg) in SD rats was also investigated. The concentration changes of sesamol were determined in various tissues and plasma within a 24 h period after oral administration of sesamol. The results showed that the oral bioavailability of sesamol was 35.5 +/- 8.5%. Sesamol was found to be able to penetrate the blood-brain barrier and go through hepatobiliary excretion. Sesamol conjugated metabolites were widely distributed in SD rat tissues, with the highest concentrations in the liver and kidneys and the lowest in the brain. It is postulated that sesamol is incorporated into the liver first and then transported to the other tissues (lung, kidneys, and brain). The major metabolites of sesamol distributed in the lung and kidney were glucuronide and sulfate.

A neurokinin-1 receptor antagonist that reduces intra-abdominal adhesion formation decreases oxidative stress in the peritoneum

Oxidative stress has been implicated in intra-abdominal adhesion formation. Substance P, a neurokinin-1 receptor (NK-1R) ligand, facilitates leukocyte recruitment and reactive oxygen species (ROS) generation. We have shown in a rat model of adhesion formation that intraperitoneal administration of a NK-1R antagonist at the time of abdominal operation reduces postoperative adhesion formation. Thus we determined the effects of NK-1R antagonist administration on peritoneal leukocyte recruitment and oxidative stress within 24 h of surgery. Adhesions were induced in Wistar rats randomly assigned to receive the antagonist or vehicle intraperitoneally. Peritoneal tissue was isolated at 2, 4, 6, and 24 h after surgery for analysis of the oxidative stress biomarkers 8-isoprostane (8-IP), protein carbonyl, NADPH oxidase, myeloperoxidase (MPO), and ICAM-1 and VCAM-1 mRNAs. Total antioxidant capacity of peritoneal fluid was also determined. MPO, NADPH oxidase, 8-IP, and protein carbonyl were elevated (P < 0.05) by 6 h. ICAM-1 mRNA was elevated (P < 0.05) by 2 h, whereas VCAM-1 levels decreased (P < 0.05) at 24 h. The NK-1R antagonist delayed the MPO rise and reduced (P < 0.05) 8-IP levels by 6 h and ICAM-1 mRNA, VCAM-1 mRNA, and protein carbonyl at 2 h. The antagonist also increased (P < 0.05) the antioxidant capacity of peritoneal fluid at all time points. These data further support a role for oxidative stress in adhesion formation and suggest that the NK-1R antagonist may limit adhesions, in part, by reducing postoperative oxidative stress through an inhibition of neutrophil recruitment and an increase in peritoneal fluid antioxidant capacity.

Effect of sesamol on radiation-induced cytotoxicity in Swiss albino mice

The radio-protective ability of sesamol (SM) at various doses viz., 0, 10, 25, 40, 50, 70 and 100mg/kg bw, administered intraperitoneally 30min prior to 9.5Gy whole-body gamma-irradiation was studied in Swiss albino mice. Radiation toxicity and mortality were observed during a period of 30 days and the percentage mortality was calculated. SM pretreatment with 50mg/kg bw was found to be the most effective dose in maintaining body weight and in reducing the percentage mortality, while 100mg/kg bw was found to be more effective in maintaining the spleen index and in stimulation of endogenous spleen colony-forming units. Pretreatment with SM (50mg/kg bw) in mice irradiated with 15Gy significantly reduced dead, inflammatory, mitotic and goblet cells in irradiated jejunum. SM at 50mg/kg bw also increased crypt cells, maintained villus height, and prevented mucosal erosion. Nuclear enlargement in epithelial cells was found less in SM-treated mice compared with the irradiated control. The radiation-induced decrease in endogenous antioxidant enzymes (GSH, GST, catalase) and the increase in lipid peroxidation were also reduced by pretreatment with SM [50 and 100mg/kg bw] at all monitored post-irradiation intervals. There was no protection at a dose less than 25mg/kg bw.

C-phycocyanin transcriptionally regulates uPA mRNA through cAMP mediated PKA pathway in human fibroblast WI-38 cells

We have previously demonstrated the efficacy of c-phycocyanin in up-regulation of urokinase-type plasminogen activator (uPA) in bovine endothelial cell line. However, the mechanism of action and pathway elucidation in uPA regulation is unclear. In experiments reported here, we have investigated the mechanism of action of c-phycocyanin (c-pc) induced uPA gene modulation in human fibroblast (WI-38) cell line. ELISA test confirmed that c-pc increased the uPA antigen whereas PAI-1 antigen level was unaffected. Treatment of cells with c-pc significantly (P<0.05) enhanced the uPA mRNA level in a dose (50 microg/ml) and time dependent (up to 4 h) manner. This effect of c-pc was abolished by treatment with dichloro-1-beta-D-ribofuranosyl benzamidazole (DRB) (10 microg/ml). Co-treatment of c-pc with 200 microg/ml cycloheximide (CHX), translation inhibitor, resulted in over accumulation of uPA mRNA. These results suggest that uPA induction by c-pc is transcriptionally regulated and does not require de novo protein synthesis. We also provide evidence that c-pc stimulates uPA gene through cAMP dependent pathway as adenylyl cyclase (AC) inhibitor, dideoxyadenosine (DDA) significantly inhibited the uPA mRNA expression and co-treatment with adenylyl cyclase analogue, dBcAMP recovered the effect of c-pc on gene activity. Furthermore, the present investigation provides evidence on the regulatory pathway involved in the c-pc stimulus. C-pc induced uPA expression was completely inhibited by PKA inhibitor (KT 5200), indicating the regulation is dependent on PKA pathway. Elimination of PKC pathway components by prolonged incubation with excess amount of phorbol 12-myristate 13-acetate (PMA) failed to abolish the c-pc effect on uPA expression indicating the regulation is independent of PKC pathway. Taken together, our data indicate that uPA gene regulation by c-pc is transcriptionally controlled through cAMP mediated PKA pathway.

Enhanced spontaneous thrombolysis: A new therapeutic challenge

Spontaneous thrombolysis is an endogenous protective mechanism against lasting arterial thrombotic occlusion, which is implicated in the pathogenesis of myocardial infarction and acute coronary events. Novel therapies for coronary heart disease (CHD) targeting atherosclerosis and thrombosis, together with cardiovascular prevention programs targeting risk-factors and lifestyle provide evidence that CHD is preventable. Although reduced fibrinolytic activity is a recognized risk-factor for ischemic cardiovascular events, it has so far been neglected. Our knowledge of the fibrinolytic effect of drugs commonly used for CHD such as antiplatelet agents (aspirin, ticlopidine, clopidogrel), anti-diabetic biguanides (phenformin, metformin) or anti-hypertensive drugs is scanty and conflicting. This is mainly due to the lack of a global test of spontaneous thrombolysis, as opposed to fibrinolysis of plasma or whole blood, i.e. the assessment of various activators and inhibitors of the fibrinolytic system. A recently described technique allows the measurement of spontaneous thrombolysis, that is, lysis of an autologous platelet-rich thrombus in the absence of added plasminogen activators. Early results suggest that this test may have significant clinical potential both in identifying those at risk of fatal cardiac events and in finding new therapeutic avenues or lifestyles to improve spontaneous thrombolytic activity.

Sesamol induces nitric oxide release from human umbilical vein endothelial cells

Sesamol, which is derived from sesame seed lignans, is reportedly an antioxidant. Nitric oxide (NO), the most important vascular relaxing factor, is regulated in the endothelium. In addition, NO is involved in protecting endothelium and has antiatherosclerotic and antithrombotic activities. The endothelium produces NO through the regulation of both endothelial NO synthase (eNOS) expression and activity in endothelial cells. This study sought to investigate the effect of sesamol on NO released from human umbilical vein endothelial cells (HUVEC) and to examine the expression and activity of eNOS. Sesamol induced NO release from endothelial cells in a dose-dependent manner (from 1 to 10 microM), as measured 24 h after treatment; the expression of the eNOS gene at both transcription and translation levels; and NOS activity in endothelial cells. The content of cGMP was also increased by sesamol through NO signaling. The transcription of eNOS induced by sesamol was confirmed through the activation of PI-3 kinase-Akt (protein kinase B) signaling. The results demonstrate that sesamol induces NOS signaling pathways in HUVEC and suggest a role for sesamol in cardiovascular reactivity in vivo.