Combination therapy with cilostazol, aripiprazole, and donepezil protects neuronal cells from β-amyloid neurotoxicity through synergistically enhanced SIRT1 expression

Alzheimer’s disease (AD) is a multi-faceted neurodegenerative disease. Thus, current therapeutic strategies require multitarget-drug combinations to treat or prevent the disease. At the present time, single drugs have proven to be inadequate in terms of addressing the multifactorial pathology of AD, and multitarget-directed drug design has not been successful. Based on these points of views, it is judged that combinatorial drug therapies that target several pathogenic factors may offer more attractive therapeutic options. Thus, we explored that the combination therapy with lower doses of cilostazol and aripiprazole with add-on donepezil (CAD) might have potential in the pathogenesis of AD. In the present study, we found the superior efficacies of donepezil add-on with combinatorial mixture of cilostazol plus aripiprazole in modulation of expression of AD-relevant genes: Aβ accumulation, GSK-3β, P300, acetylated tau, phosphorylated-tau levels, and activation of α-secretase/ADAM 10 through SIRT1 activation in the N2a Swe cells expressing human APP Swedish mutation (N2a Swe cells). We also assessed that CAD synergistically raised acetylcholine release and choline acetyltransferase (CHAT) expression that were declined by increased β-amyloid level in the activated N2a Swe cells. Consequently, CAD treatment synergistically increased neurite elongation and improved cell viability through activations of PI3K, BDNF, β-catenin and a7-nicotinic cholinergic receptors in neuronal cells in the presence of Aβ1-42. This work endorses the possibility for efficient treatment of AD by supporting the synergistic therapeutic potential of donepezil add-on therapy in combination with lower doses of cilostazol and aripiprazole.

Combination therapy with cilostazol, aripiprazole, and donepezil protects neuronal cells from β-amyloid neurotoxicity through synergistically enhanced SIRT1 expression

Alzheimer’s disease (AD) is a multi-faceted neurodegenerative disease. Thus, current therapeutic strategies require multitarget-drug combinations to treat or prevent the disease. At the present time, single drugs have proven to be inadequate in terms of addressing the multifactorial pathology of AD, and multitarget-directed drug design has not been successful. Based on these points of views, it is judged that combinatorial drug therapies that target several pathogenic factors may offer more attractive therapeutic options. Thus, we explored that the combination therapy with lower doses of cilostazol and aripiprazole with add-on donepezil (CAD) might have potential in the pathogenesis of AD. In the present study, we found the superior efficacies of donepezil add-on with combinatorial mixture of cilostazol plus aripiprazole in modulation of expression of AD-relevant genes: Aβ accumulation, GSK-3β, P300, acetylated tau, phosphorylated-tau levels, and activation of α-secretase/ADAM 10 through SIRT1 activation in the N2a Swe cells expressing human APP Swedish mutation (N2a Swe cells). We also assessed that CAD synergistically raised acetylcholine release and choline acetyltransferase (CHAT) expression that were declined by increased β-amyloid level in the activated N2a Swe cells. Consequently, CAD treatment synergistically increased neurite elongation and improved cell viability through activations of PI3K, BDNF, β-catenin and a7-nicotinic cholinergic receptors in neuronal cells in the presence of Aβ1-42. This work endorses the possibility for efficient treatment of AD by supporting the synergistic therapeutic potential of donepezil add-on therapy in combination with lower doses of cilostazol and aripiprazole.

HO-1 Induced by Cilostazol Protects Against TNF-alpha-associated Cytotoxicity via a PPAR-gamma-dependent Pathway in Human Endothelial Cells

A large body of evidence has indicated that induction of endogenous antioxidative proteins seems to be a reasonable strategy for delaying the progression of cell injury. In our previous study, cilostazol was found to increase the expression of the antioxidant enzyme heme oxygenase-1 (HO-1) in synovial cells. Thus, the present study was undertaken to examine whether cilostazol is able to counteract tumor necrosis factor-alpha (TNF-alpha)-induced cell death in endothelial cells via the induction of HO-1 expression. We exposed human umbilical vein endothelial cells (HUVECs) to TNF-alpha (50 ng/ml), with or without cilostazol (10 microM). Pretreatment with cilostazol markedly reduced TNF-alpha-induced viability loss in the HUVECs, which was reversed by zinc protoporphyrine IX (ZnPP), an inhibitor of HO-1. Moreover, cilostazol increased HO-1 protein and mRNA expression. Cilostazol-induced HO-1 induction was markedly attenuated not only by ZnPP but also by copper-protoporphyrin IX (CuPP). In an assay measuring peroxisome proliferator-activated receptor-gamma (PPAR-gamma) transcription activity, cilostazol directly increased PPAR-gamma transcriptional activity which was completely abolished by HO-1 inhibitor. Furthermore, increased PPAR-gamma activity by cilostazol and rosiglitazone was completely abolished in cells transfected with HO-1 siRNA. Taken together, these results indicate that cilostazol up-regulates HO-1 and protects cells against TNF-alpha-induced endothelial cytotoxicity via a PPAR-gamma-dependent pathway.

Rebamipide-induced downregulation of phospholipase D inhibits inflammation and proliferation in gastric cancer cells

Rebamipide a gastroprotective drug, is clinically used for the treatment of gastric ulcers and gastritis, but its actions on gastric cancer are not clearly understood. Phospholipase D (PLD) is overexpressed in various types of cancer tissues and has been implicated as a critical factor in inflammation and carcinogenesis. However, whether rebamipide is involved in the regulation of PLD in gastric cancer cells is not known. In this study, we showed that rebamipide significantly suppressed the expression of both PLD1 and PLD2 at a transcriptional level in AGS and MKN-1 gastric cancer cells. Downregulation of PLD expression by rebamipide inhibited its enzymatic activity. In addition, rebamipide inhibited the transactivation of nuclear factor kappa B (NFkappaB), which increased PLD1 expression. Rebamipide or PLD knockdown significantly suppressed the expression of genes involved in inflammation and proliferation and inhibited the proliferation of gastric cancer cells. In conclusion, rebamipide-induced downregulation of PLD may contribute to the inhibition of inflammation and proliferation in gastric cancer.

Synergistic Efficacy of Concurrent Treatment with Cilostazol and Probucol on the Suppression of Reactive Oxygen Species and Inflammatory Markers in Cultured Human Coronary Artery Endothelial Cells

In the present study, we aimed to identify the synergistic effects of concurrent treatment of low concentrations of cilostazol and probucol to inhibit the oxidative stress with suppression of inflammatory markers in the cultured human coronary artery endothelial cells (HCAECs). Combination of cilostazol (0.3~3micrometer) with probucol (0.03~0.3micrometer) significantly suppressed TNF-alpha-stimulated NAD(P)H-dependent superoxide, lipopolysaccharide (LPS)-induced intracellular reactive oxygen species (ROS) production and TNF-alpha release in comparison with probucol or cilostazol alone. The combination of cilostazol (0.3~3micrometer) with probucol (0.1~0.3micrometer) inhibited the expression of vascular cell adhesion molecule-1 (VCAM-1) and monocyte chemoattractant protein-1 (MCP-1) more significantly than did the monotherapy with either probucol or cilostazol. In line with these results, combination therapy significantly suppressed monocyte adhesion to endothelial cells. Taken together, it is suggested that the synergistic effectiveness of the combination therapy with cilostazol and probucol may provide a beneficial therapeutic window in preventing atherosclerosis and protecting from cerebral ischemic injury.

KR 31378, a potent antioxidant, inhibits apoptotic death of A7r5 cells

This work describes the pharmacological inhibition by KR 31378 and its acetyl metabolite, KR 31612, of the apoptotic cell death induced by H2O2 in the A7r5 cells. Exposure of A7r5 cells to H2O2 (0.5 mM) induced a concentration-dependent cytotoxicity in association with oligonucleosomal DNA fragmentation. H2O2-induced cell death was potently suppressed by KR 31378, KR 31612, alpha-tocopherol or trolox. Additionally, the apoptotic death of A7r5 cells (DNA ladders on electrophoresis) was also strongly suppressed by KR 31378 and KR 31612, but to a less degree by alpha-tocopherol and trolox. As a mechanistic study, incubation with H2O2 markedly showed a decreased Bcl-2 level and, in contrast, increased Bax protein and cytochrome C release, which were significantly and concentration-dependently reversed by KR 31378 and KR 31612 as well as by alpha-tocopherol and trolox. KR 31378 and alpha-tocopherol significantly reduced lipid peroxidation in accordance with reduced intracellular ROS and peroxyl radical. These results suggest that KR 31378 has a therapeutic potential against the apoptotic injury via mediation of antioxidative stress.

Effects of Polyamines on TNFalpha- or Tamoxifen-induced Apoptosis in Human Breast Cancer Cells / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: To investigate the effects of polyamines on tumor necrosis factor alpha (TNFalpha)-or tamoxifen (TAM)-induced apoptosis in estrogen receptor (ER)-positive MCF- 7 and ER-negative MDA-MB-231 human breast cancer cells. MATERIALS AND METHODS: Cell viability was assessed by using MTT assay. Reactive oxygen species (ROS) generation was measured using 2', 7'-dichlorofluorescin diacetste (DCFDA) by fluorescence plate reader. DNA fragmentation was assessed by 1.5% agarose gel electrophoresis. RESULTS: TNFalpah and TAM showed significant dose- and time- dependent inhibitory effects on the growth of MCF-7 human cells. However, the growth of MDA-MB-231 cells were not inhibited by TNFalpha or TAM treatment. The generation of ROS was increased in dose-and time-dependent manner by TNFalpha treatment in MCF-7 cells. Polyamines, especially spermine suppressed TNFalpha-induced ROS generation in MCF-7 cells. Antioxidant effects of polyamines were also demonstrated by DNA fragmentation, cell morphology as well as ROS generation assay. Polyamines also blocked TAM-induced cell death in MCF-7 cell. However, MDA-MB-231 cells showed resistance to the cytotoxic effects of TNFalpha or TAM. CONCLUSION: These results suggest that polyamines may prevent TNFalpha or TAM-induced apoptosis in MCF-7 human breast cancer cells.

Altered cerebral vasomotion with decreased CGRP level in pial arteries of spontaneously hypertensive rats

The study aims to identify the mechanism (s) underlying the altered vasodilatory responses of the pial artery of spontaneously hypertensive rats (SHR) under a hypothesis that calcitonin gene-related peptide (CGRP) exerts a modulator role in the autoregulation of cerebral blood flow (CBF). The animals were divided into four groups: 1) Sprague-Dawley rats (SDR), 2) Wistar rats (WR), 3) SHR with high blood pressure (BP gtoreq 150 mmHg), and 4) SHR with normotensive BP (ltoreq 150 mmHg). The lower limit of CBF autoregulation in SHR shifted to a higher BP (82.8 +/- 9.3 mmHg, P < 0.05) than that in SDR (58.9 +/- 5.7 mmHg). In SHR, whether the BP levels were high or normotensive, the vasodilator responses to a stepwise hypotension were significantly attenuated unlike with SDR and WR. When artificial cerebrospinal fluid (CSF) containing capsaicin (3 X 10-7 M) was suffused over the cortical surface, a transient increase in pial arterial diameter was observed in the SHR with high or normotensive BP. In contrast, SDR and WR showed a large increase in diameter, and the increase was sustained for over 10 minutes. In line with these results, the basal releases of CGRP-like immunoreactivity (CGRP-LI) in the isolated pial arteries from SHR with high and normotensive BP were 12.5 +/- 1.4 and 9.8 +/- 2.8 fmole/mm2/60 min (P < 0.05), while those from SDR and WR were 25.5 +/- 3.1 and 24.6 +/- 3.1 fmole/mm2/60 min, respectively. The isolated basilar arteries showed similar results to those of the pial arteries in SHR. Thus, it is summarized that, in the SHR, the reduced autoregulatory vasodilator responses to stepwise hypotension and capsaicin may be, in part, ascribed to the decreased release of CGRP from the perivascular sensory nerve fibers of the pial arteries, and that altered vasomotor activity in SHR may not be related with the hypertensive tone.

Study on Therapeutic Effect of Pentoxifylline on Developmet of Multiple Organ Dysfuction Caused by Endotoxin in Rat / 대한내과학회지

OBJECTIVES: Septic shock is characterized by the circulatory failure including vasodilation, hyporeactivity to vasoconstrictor agents and organ ischemia in association with multiple organ failure and increased platelet aggregation and blood coagulation. In the present study, we investigated the preventive effects of N-nitro-L-arginine methyl ester (L-NAME, 30mg/kg, i.p.), a non-selective nitric oxide synthase (NOS) inhibitor, S-methylisothiourea sulfate (SMT, 5mg/kg, i.p.) and pentoxifylline (PTX,10mg/kg, i.p.) on the multiple organ dysfunction in a rat model of circulatory shock induced by bacterial endotoxin (E. coli lipopolysaccharide: LPS) and discussed the mechanism underlying the development of multiple organ failure. METHODS: The effect of each other N-nitro-L-arginine methyl ester(L-NAME, 30 mg/kg, i.p.), a non-selective nitric oxide synthase(NOS) inhibitor, S-methyli-sothiourea sulfate(SMT, 5mg/kg, i.p.) and pentoxifylline (PTX, 10mg/kg, i.p.) were comparatively evaluated following inducing circulatory shock by means of infusion of bacterial endotoxin to the rat model. RESULTS: 1) The systemic mean arterial blood pressure decreased by 48.7mmHg and vascular hyporeactivity to noradrenaline injection(1 g/kg, i.v.) upon intravenous administration of LPS. 2) Endotoxemia for 6hours resulted in little change in the numbers of white blood cells and neutrophils but a significant reduction in the numbers of platelets. The variables were not affected by the inhibitors. 3) Endotoxemia for 6hours caused a significant increase in serum nitric oxide level (P<0.01) which was inhibited by SMT, but not by L-NAME and PTX. 4) Upon injection of LPS, serum creatinine(0.65+/-0.08mg/dl) and urea(28.7+/-5.9mg/dl) were significantly elevated to 0.92+/-0.12 (P<0.05) and 54.3+/-2.1mg/dl (P< 0.01). These elevated levels were significantly attenuated by PTX but not by L-NAME and SMT. 5) Endotoxemia for 6 hours resulted in a significant increases in serum ALT(988.8+/-28.2 IU/L, P<0.01) and AST levels(1470.5+/-396.5 IU/L, P<0.01) from basal levels of ALT(67.8+/- 11.7IU/L) and AST(170.3+/-14.8IU/L). These increased activities were significantly attenuated by PTX, but not by L-NAME and SMT. The level of LDH(1279.8+/-156.2IU/L) was significantly increased by LPS treatment to 2932.0+/-519.9IU/L (P<0.05), which was inhibited by PTX. 6) Upon LPS treatment, the myeloperoxidase activity in the lung homogenate was significantly increased by LPS treatment (P<0.05), whereas that in the liver showed less change. The increased activity was reduced by PTX (P<0.05), but not by L-NAME and SMT. 7) The level of serum malondialdehyde, an index of lipid peroxidation by oxygen free radicals, was little influenced by LPS. CONCLUSION: Based on these results, it is summarized that PTX characteristically inhibited the development of multiple ogran dysfunction in a murine model of endotoxemia. Thus, it is concluded that the formation of TNF and increased activity of neutrophils may importantly contribute to the development of LPS-induced endotoxemia.

In vitro pharmacological characteristics of SKP-450, a novel K+ channel opener, in non-vascular smooth muscles in comparison with levcromakalim

In the present study, we characterized the non-vascular smooth muscle relaxant effects of a novel benzoyran derivative, SKP-450 (2-(2"(1",3"-dioxolone)-2-methyl-4-(2'-oxo-1'-pyrrolidinyl)-6-nitro- 2H-1-benzopyran) and its metabolite, SKP-310, in comparison with levcromakalim (LCRK). In the rat stomach fundus, the spontaneous motility stimulated by 10-6.5 M bethanechol was completely eliminated not only by 10(-7) M SKP-450 but also by 10(-6) M LCRK, which were blocked by 10(-6) M glibenclamide. The inhibitory effect of SKP-450 (pD2, 3.94 +/- 0.66) was much less than LCRK (pD2, 5.73 +/- 0.38, P < 0.05). In the bethanechol (10(-6.5) M)-stimulated urinary bladder, the tonus was decreased in association with elimination of spontaneous motility by 10(-7) M SKP-450 and 10-6 M LCRK (pD2, 6.77 +/- 0.06) (P < 0.05), which were inhibitable by 10-6 M glibenclamide. The inhibitory effect of SKP-450 (pD2, 7.66 +/- 0.05) was significantly more potent than that of LCRK (pD2, 6.77 +/- 0.06, P < 0.05). In the rat uterus stimulated by PGF2alpha (10(-7) M), both increased tonus and spontaneous motility were eliminated by 10(-6) M LCRK with slight depression of the tonus, but not by SKP-450 (10(-5) M). The stimulated trachea of guinea-pig by 10-6.5 M bethanechol was moderately suppressed by SKP-450 (10(-6)~10(-5) M) but little by SKP-310. In association with the relaxant effects, SKP-450 (10(-6) M) and LCRK (10(-5) M) caused a significant stimulation of the 86Rb efflux from rat urinary bladder and stomach fundus, which were antagonized by 10(-5) M glibenclamide, whereas the K+ channel openers could not exert a stimulation of the 86Rb efflux from rat uterus. In conclusion, it is suggested that SKP-450 exerts potent relaxant effects on the urinary bladder detrusor muscle and duodenum, whereas it shows much less effect on stomach fundus and uterus as contrasted to LCRK.

Pharmacological evidence that cromakalim inhibits Ca2+ release from intracellular stores in porcine coronary artery

In the present study, it was aimed to further identify the intracellular action mechanism of cromakalim and levcromakaliin in the porcine coronary artery. In intact porcine coronary arterial strips loaded with fura-2/AM, acetylcholine caused an increase in intracellular free Ca2+ ((Ca2+)-i) in association with a contraction in a concentration-dependent manner. Cromakalim (1 micrometer) caused a reduction in acetylcholine-induced increased (Ca2+)-i not only in the normal physiological salt solution (PSS) but also in Ca2+ -free PSS (containing 1mM EGTA). In the skinned strips prepared by exposure of tissue to 20 micrometer beta-escin, inositol 1,4,5-trisphosphate (IP-3) evoked an increase in (Ca2+)-i but it was without effect on the intact strips. The IP-3-induced increase in (Ca2+)-i was inhibited by cromakalim by 78% and levcromakalim by 59% (1 micrometer, each). Pretreatment with glibenclamide (a blocker of ATP-sensitive K+ channels, 10 micrometer and apamin (a blocker of small conductance Ca2+/-activated K+ channels, 1 micrometer strongly blocked the effect of cromakalim and levcromakalim. However, charybdotoxin (a blocker of large conductance Ca2+ -activated K+ channels, 1-micrometer) was without effect. In addition, cromakalim inhibited the GTP-gamma-S (100 micrometer, nonhydrolysable analogue of GTP)-induced increase in (Ca2+)-i. Based on these results, it is suggested that cromakalim and levcromakalim exert a potent vasorelaxation, in part, by acting on the K+ channels of the intracellular sites (e.g., sarcoplasmic reticulum membrane), thereby, resulting in decrease in release of Ca2+ from the intracellular storage site.

Mechanisms underlying relaxations caused by angiotensin II and its analogs in isolated rabbit mesenteric artery

In the present study, we characterized the angiotensin II (AII)-induced relaxations in the phenylephrineprecontracted rabbit mesenteric arteries with endothelium. 1) AII-induced relaxation was consistently observed in the rabbit mesenteric arteries with and without endothelium, but not in the aortic segment with endothelium. 2) AII-induced endothelium-dependent relaxation was markedly inhibited by Nw-nitro-L-arginine (L-NNA, 100 micrometer), methylene blue (10 micrometer) and LY83583 (10 micrometer), respectively. 3) Inhibition of cyclooxygenase with indomethacin (10 micrometer) strongly decreased the vasorelaxant response to AII irrespective of the presence of endothelium. 4) 7-Ethoxyresorufin (1 micrometer) and clotrimazole (1 micrometer), inhibitors of cytochrome P-450-dependent arachidonic acid metabolism, greatly attenuated the vasodilator response to All. 5) Carbacyclin, arachidonic acid and prostaglandin F2alpha, (PGF2alpha) caused concentration-dependent relaxations in the mesenteric artery with endothelium, which were inhibited by L-NNA and methylene blue. 6) AII and PGF2alpha, significantly stimulated cyclic GMP formation in the mesenteric arteries with endothelium, which was inhibited by L-NNA and methylene blue, respectively. 7) AII enhanced synthesis of PGF2a and 6-keto PGF1a from the arterial segments with endothelium, which was inhibitable by indomethacin, but not by L-NNA. In conclusion, the vasorelaxant responses to AII of the rabbit mesenteric artery with endothelium are subserved by arachidonic acid and its metabolites produced via activation of cyclooxygenase and cytochrome P-450 enzyme as well as by nitric oxide.

Studies on Mechanism of Vascular Hyporeactivity of Meaenteric Artery from Septic Rats

No abstract available.

Expandable Metallic Stent in the Treatment of Subglottic Tracheal Stenosis: Report of Long-term Failure in 4 Cases

Subglottic stenosis is more likely to develop secondary to endotracheal intubation if one or more traumarelated risk factors are involved. Subglottic stenosis have been dealt with many medicosurgical procedures such as dilatation, stent, laryngofissure with or without skin of mucosal graff, and segmental resection. We report longterm failure of expandable metallic stent in the treatment of subglottic tracheal steno$is in 4 cases which had been presented with respiration difficulty due to framework problem of subglottic trachea after surgical operation.

Expandable metallic stent: experimental and clinical experience in tracheobronchial tree

No abstract available.

Characterization of lnhibition by Nifedipine and Nitroprusside of the Pressor Respones to alpha1-Adrenoceptor Agonists Cirazoline and Sgd 101/75 in Pithed Rats

In this study the effects of two unrelated vasodilators, nifedipine and nitroprusside, on the pressor responsiveness to the 1-adrenoceptor full agonist cirazoline and partial agonist Sgd 101/75 in pithed rats were examined. The experiments were performed on the vasoconstriction which was mediated by newly synthetized 1-adrenoceptors after removal of existing 1-adrenoceptors by phenoxybenzamine treatment(5mg/kg, i. p.). The t1/2 for recovery of the maximum response and ED50 of cirazoline were 23.1 +/- 5.5 and 26.9 +/- 7.4 hours, respectively, while that for recovery of the maximum response of Sgd 101/75 was 59.2 +/- 18.9 hours. The relationship between the pressor response and the fractional receptor occupancy for cirazoline showed a rectangular hyperbola. This occupancy-response curve markedly shifted to the right one day after phenoxybenzamine and subsequently returned to the control, indicative of a large receptor reserve. However, for Sgd 101/75 the occupancy-response curve exerted less of a hyperbola and shifited little after phenoxybenzamine. While the maximum response to cirazoline in the control rats was resistant to inhibition by the calcium entry blocker nifedipine, this resistance was significantly reduced one and 3 days after phenoxybenzamine, just as the maximum response to Sgd 101/75 was sensitive to nifedipine in the control rats. Likewise, when nitroprusside was used instead, the results were similar for the cirazoline and Sgd 101/75 effects. In summary, it seems unlikely that the resistance to the calcium entry blocker of the full agonist effect can be wholly ascribed either to the receptor reserves or to the differential calcium utilization itself. Alternatively, it is suggested that the differential resistance to calcium antagonists can result from the magnitude of the variables involved in the activation of 1-adrenoceptor coupling processes depending on the full or partial agonist.