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The Impact of Uremic Toxins on Vascular Smooth Muscle Cell Function. Toxins (Basel) 2018; 10:toxins10060218. [PMID: 29844272 PMCID: PMC6024314 DOI: 10.3390/toxins10060218] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 05/26/2018] [Accepted: 05/27/2018] [Indexed: 12/18/2022] Open
Abstract
Chronic kidney disease (CKD) is associated with profound vascular remodeling, which accelerates the progression of cardiovascular disease. This remodeling is characterized by intimal hyperplasia, accelerated atherosclerosis, excessive vascular calcification, and vascular stiffness. Vascular smooth muscle cell (VSMC) dysfunction has a key role in the remodeling process. Under uremic conditions, VSMCs can switch from a contractile phenotype to a synthetic phenotype, and undergo abnormal proliferation, migration, senescence, apoptosis, and calcification. A growing body of data from experiments in vitro and animal models suggests that uremic toxins (such as inorganic phosphate, indoxyl sulfate and advanced-glycation end products) may directly impact the VSMCs’ physiological functions. Chronic, low-grade inflammation and oxidative stress—hallmarks of CKD—are also strong inducers of VSMC dysfunction. Here, we review current knowledge about the impact of uremic toxins on VSMC function in CKD, and the consequences for pathological vascular remodeling.
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Pazio A, Santos VB, Salles Junior GS. Effect of cilostazol in experimental model of degloving injuries in rat limbs. Acta Cir Bras 2018; 33:296-305. [PMID: 29768532 DOI: 10.1590/s0102-865020180040000001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Accepted: 03/20/2018] [Indexed: 05/29/2023] Open
Abstract
PURPOSE To evaluate the effect of the cilostazol on the evolution of partially avulsed flaps, using experimental model of cutaneous degloving in rat limbs. METHODS A controlled and randomized experimental study was carried out in which the blood flow and the percentage of flap necrosis were evaluated. We compared the study group, which received cilostazol, and the control group, which received enteral saline solution in the postoperative period. The blood flow in the flap was evaluated through Laser Doppler flowmetry, and a planimetry using the IMAGE J® software was employed for the calculation of the area of necrosis. RESULTS Enteral administration of cilostazol was associated with a higher mean blood flow in all regions of the flap, with a statistically significant difference in the proximal and middle regions (p<0.001) and a lower percentage of necrotic area in the flap (p<0.001). CONCLUSION Postoperative enteral administration of cilostazol increased blood flow and decreased the total area of necrosis of avulsed cutaneous flaps of rat limbs.
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Affiliation(s)
- André Pazio
- MD, Resident, Division of Plastic Surgery, Department of Surgery, Clinics Hospital, Universidade Ferederal do Paraná (UFPR), Curitiba-PR, Brazil. Scientific and intellectual content of the study, analysis and interpretation of data, technical procedures, statistical analysis, manuscript preparation and writing
| | - Vital Burko Santos
- Graduate student, Pontifícia Universidade Católica do Paraná (PUC-PR), Curitiba-PR, Brazil. Acquisition, analysis and interpretation of data; technical procedures; manuscript preparation
| | - Guataçara Schenfelder Salles Junior
- PhD, Associate Professor, Experimental Surgery Division, School of Medicine, PUC-PR, Curitiba-PR, Brazil. Scientific, intellectual, conception and design of the study; critical revision; final approval
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Molinari C, Morsanuto V, Polli S, Uberti F. Cooperative Effects of Q10, Vitamin D3, and L-Arginine on Cardiac and Endothelial Cells. J Vasc Res 2018; 55:47-60. [PMID: 29301117 DOI: 10.1159/000484928] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 11/01/2017] [Indexed: 12/13/2022] Open
Abstract
This work demonstrates the cooperative effect of Q10, vitamin D3, and L-arginine on both cardiac and endothelial cells. The effects of Q10, L-arginine, and vitamin D3 alone or combined on cell viability, nitric oxide, and reactive oxygen species productions in endothelial and cardiac cells were studied. Moreover, the involvement of PI3K/Akt and ERK/MAPK pathways leading to eNOS activation as well as the involvement of vitamin D receptor were also investigated. The same agents were tested in an animal model to verify vasodilation, nitric oxide, and reactive oxygen species production. The data obtained in this work demonstrate for the first time the beneficial and cooperative effect of stimulation with Q10, L-arginine, and vitamin D3. Indeed, in cardiac and endothelial cells, Q10, L-arginine, and vitamin D3 combined were able to induce a nitric oxide production higher than the that induced by the 3 substances alone. The effects on vasodilation induced by cooperative stimulation have been confirmed in an in vivo model as well. The use of a combination of Q10, L-arginine, and vitamin D to counteract increased free radical production could be a potential method to reduce myocardial injury or the effects of aging on the heart.
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Affiliation(s)
- Claudio Molinari
- Laboratory of Physiology, Department of Translational Medicine, University of Eastern Piedmont, Novara, Italy
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Burusapat C, Paengnoi J, Satayasoontorn K. An experimental study of the effect of pre-operative administration of cilostazol on random skin flap survival in rats: double blinded randomized controlled trial. ANNALS OF SURGICAL INNOVATION AND RESEARCH 2015; 9:2. [PMID: 25937828 PMCID: PMC4416283 DOI: 10.1186/s13022-015-0011-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Accepted: 04/20/2015] [Indexed: 11/10/2022]
Abstract
BACKGROUND Insufficient arterial blood flow is the one cause of flap necrosis. Cilostazol is an inhibitor of phosphodiesterase III and increases cyclic AMP level in vascular smooth muscle cell causing vasodilation. Therefore, effect of cilostazol is expected to improve the viability of the flap. METHODS Double blinded randomized controlled trial was conducted. The study was to compare the survival of dorsal rat flaps between preoperative cilostazol supplemented diet and regular diet. The flap survival area was measured using PixArea Image software on post operative day 1,3,5 and 7. Fluorescein injection was performed to evaluate the exactly area of flap survival on postoperative day 7 and morphology of arterioles and venules were examined by histopathologic examination. RESULTS A statistical significance was found in the percentage of area of flap survival between cilostazol supplemented diet and control group on postoperative day 3, 5 and 7 (p < 0.05). Fluorescein injection showed the higher area of flap survival in cilostazol group than the control group (p < 0.05). Histopathologic examination showed dilation of vessels in the cilostazol group. CONCLUSION Preoperative cilostazol in rats can enhance skin flap survival.
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Affiliation(s)
- Chairat Burusapat
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Phramongkutklao Hospital and Phramongkutklao College of Medicine, 315 Ratchawithi Road, Thung Phayathai, Ratchathewi, Bangkok, 10400 Thailand
| | - Janjira Paengnoi
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Phramongkutklao Hospital and Phramongkutklao College of Medicine, 315 Ratchawithi Road, Thung Phayathai, Ratchathewi, Bangkok, 10400 Thailand
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Yang M, Xiao Z, Lv Q, Liu X, Zhou L, Chen X, Chen M, Fang L, Xie X, Hu J. The functional expression of TLR3 in EPCs impairs cell proliferation by induction of cell apoptosis and cell cycle progress inhibition. Int Immunopharmacol 2011; 11:2118-24. [PMID: 21964048 DOI: 10.1016/j.intimp.2011.09.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 09/14/2011] [Accepted: 09/14/2011] [Indexed: 01/22/2023]
Abstract
Toll-like receptor 3 (TLR3), a member of the TLR family that recognizes double-stranded RNA (dsRNA), plays an important role in antiviral immunity. TLR3 is widely expressed in various cells and the activation of TLR3 induces cell apoptosis in some cells. However, the effect of TLR3 on cell proliferation in endothelial progenitor cells (EPCs) is unclear. In this study, we found that EPCs expressed high levels of TLR1, 3, 4, and 6 and low levels of TLR2, 5, 7, 8, and 10. The treatment of EPCs with TLR3 agonist Poly I:C up-regulated the expression of cytokines IL-1β, IL-6, IL-8, TNF-α, IFN-α, and IFN-β, indicating that EPCs expressed functional TLR3. Moreover, Poly I:C treatment induced cell cycle progress inhibition and cell apoptosis, leading to the inhibition of cell proliferation. Further studies indicated that IL-1β was involved in TLR3-induced cell proliferation inhibition, as IL-1β inhibited cell proliferation in a dose-dependent manner, and the IL-1β receptor type I (IL-1R1)-neutralizing antibody ameliorated Poly I:C-induced cell proliferation inhibition. Taken together, these results suggest that Poly I:C impairs cell proliferation by inducing cell cycle progress inhibition and cell apoptosis via TLR3 in EPCs.
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Affiliation(s)
- Mei Yang
- Department of Geriatric Cardiology, Xiangya Hospital,Central South University, Changsha, 410008, China
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Yoo AR, Koh SH, Cho GW, Kim SH. Inhibitory effects of cilostazol on proliferation of vascular smooth muscle cells (VSMCs) through suppression of the ERK1/2 pathway. J Atheroscler Thromb 2010; 17:1009-18. [PMID: 20720374 DOI: 10.5551/jat.4309] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
AIM The abnormal proliferation of vascular smooth muscle cells (VSMCs) in arterial walls is an important pathogenic factor of vascular disorders such as atherosclerosis and restenosis after angioplasty. During atherogenesis or in response to vessel injury, VSMC proliferation is induced by a number of peptide growth factors released from platelets and VSMCs. Cilostazol is a phosphodiesterase (PDE) 3 inhibitor that increases intracellular cAMP levels and decreases intracellular Ca(2+) levels, inhibiting platelet aggregation and inducing vasodilatation. Cilostazol is also known to have an inhibitory effect on the proliferation of VSMCs, but the anti-proliferative mechanism of cilostazol in VSMCs has not yet been established. In the present study, we investigated whether the anti-proliferative mechanism of cilostazol is associated with the suppression of extracellular signal-regulated kinases (ERK) and phosphatidylinositol 3 kinase (PI3K) signaling pathways. METHODS To confirm the anti-proliferative effects of cilostazol on VSMCs, VSMCs were induced to proliferate by serum-induced mitogenesis and then were treated with cilostazol for 24 h. And, to investigate whether the anti-proliferative mechanism of cilostazol in VSMCs involves the suppression of the ERK and PI3K pathways, expression of the phosphorylated forms of ERK1/2, Raf, Akt, and glycogen synthase kinase (GSK)-3 were evaluated by western blot. RESULTS Cilostazol inhibited VSMC proliferation in a dose-dependent manner. Phosphorylated ERK1/2 and Raf were significantly reduced in a dose-dependent manner, whereas phosphorylated Akt and GSK-3 were not changed. CONCLUSION These results suggest that suppression of the ERK pathway but not the PI3K pathway is an important mechanism in the anti-proliferative effect of cilostazol on VSMCs.
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Affiliation(s)
- A Rum Yoo
- Department of Neurology, Hanyang University College of Medicine, 17 Haengdang-dong-dong, Seoul, Korea
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YOSHIMOTO T, FUJIMOTO S, MURAKI M, KOBAYASHI R, YOSHIDUMI T, YAMAUCHI T, TOKUDA K, KANEKO S. Cilostazol May Suppress Restenosis and New Contralateral Carotid Artery Stenosis After Carotid Endarterectomy. Neurol Med Chir (Tokyo) 2010; 50:525-9. [DOI: 10.2176/nmc.50.525] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
| | - Shin FUJIMOTO
- Department of Neurosurgery, Kashiwaba Neurosurgical Hospital
| | - Mutsuko MURAKI
- Department of Neurophysiology, Kashiwaba Neurosurgical Hospital
| | - Rina KOBAYASHI
- Department of Neurosurgery, Kashiwaba Neurosurgical Hospital
| | | | - Tohru YAMAUCHI
- Department of Neurosurgery, Kashiwaba Neurosurgical Hospital
| | - Kouichi TOKUDA
- Department of Neurosurgery, Kashiwaba Neurosurgical Hospital
| | - Sadao KANEKO
- Department of Neurosurgery, Kashiwaba Neurosurgical Hospital
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Wang X, Yan L, Chen W, Xu L, Zhang X. The renal protective effects of cilostazol on suppressing pathogenic thrombospondin-1 and transforming growth factor-beta expression in streptozotocin-induced diabetic rats. J Int Med Res 2009; 37:145-53. [PMID: 19215684 DOI: 10.1177/147323000903700117] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Diabetic nephropathy is a major complication facing patients with diabetes mellitus. The renal protective effects of the phosphodiesterase III inhibitor, cilostazol, were investigated in rats with streptozotocin-induced diabetes. Expression of thrombospondin-1 (TSP-1) and transforming growth factor-beta (TGF-beta) in the kidney was measured by immunohistochemistry and real-time reverse transcription-quantitative polymerase chain reaction analysis in diabetic rats, cilostazol-treated diabetic rats and control rats. Ultrastructural changes in the kidney were also analysed using microscopy. Four weeks after the induction of diabetes, TSP-1 and TGF-beta expression was significantly increased in the kidneys of diabetic rats compared with the control and was significantly lower in cilostazol-treated diabetic rats than in the untreated diabetic rats. Microscopy revealed characteristic renal pathology in the diabetic group, which was rarely seen in the cilostazol-treated diabetic rats. In conclusion, this study indicates that cilostazol treatment of diabetic rats effectively prevents pathological kidney changes, possibly via the down-regulation of TSP-1 and TGF-beta expression compared with untreated rats.
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Affiliation(s)
- X Wang
- The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
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Grossini E, Molinari C, Caimmi PP, Uberti F, Vacca G. Levosimendan induces NO production through p38 MAPK, ERK and Akt in porcine coronary endothelial cells: role for mitochondrial K(ATP) channel. Br J Pharmacol 2009; 156:250-61. [PMID: 19154424 DOI: 10.1111/j.1476-5381.2008.00024.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Levosimendan acts as a vasodilator through the opening of ATP-sensitive K(+) channels (K(ATP)) channels. Moreover, the coronary vasodilatation caused by levosimendan in anaesthetized pigs has recently been found to be abolished by the nitric oxide synthase (NOS) inhibitor N(omega)-nitro-L-arginine methyl ester, indicating that nitric oxide (NO) has a role in the vascular effects of levosimendan. However, the intracellular pathway leading to NO production caused by levosimendan has not yet been investigated. Thus, the purpose of the present study was to examine the effects of levosimendan on NO production and to evaluate the intracellular signalling pathway involved. EXPERIMENTAL APPROACH In porcine coronary endothelial cells (CEC), the release of NO in response to levosimendan was examined in the presence and absence of N(omega)-nitro-L-arginine methyl ester, an adenylyl cyclase inhibitor, K(ATP) channel agonists and antagonists, and inhibitors of intracellular protein kinases. In addition, the role of Akt, ERK, p38 and eNOS was investigated through Western blot analysis. KEY RESULTS Levosimendan caused a concentration-dependent and K(+)-related increase of NO production. This effect was amplified by the mitochondrial K(ATP) channel agonist, but not by the selective plasma membrane K(ATP) channel agonist. The response of CEC to levosimendan was prevented by the K(ATP) channel blockers, the adenylyl cyclase inhibitor and the Akt, ERK, p38 inhibitors. Western blot analysis showed that phosphorylation of the above kinases lead to eNOS activation. CONCLUSIONS AND IMPLICATIONS In CEC levosimendan induced eNOS-dependent NO production through Akt, ERK and p38. This intracellular pathway is associated with the opening of mitochondrial K(ATP) channels and involves cAMP.
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Affiliation(s)
- E Grossini
- Laboratorio di Fisiologia, Dipartimento di Medicina Clinica e Sperimentale, Facoltà di Medicina e Chirurgia, Università del Piemonte Orientale A. Avogadro, via Solaroli 17, Novara, Italy.
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YOSHIMOTO T, SHIRASAKA T, FUJIMOTO S, YOSHIDUMI T, YAMAUCHI T, TOKUDA K, KANEKO S, KASHIWABA T. Cilostazol May Prevent Cerebral Vasospasm Following Subarachnoid Hemorrhage. Neurol Med Chir (Tokyo) 2009; 49:235-40; discussion 240-1. [DOI: 10.2176/nmc.49.235] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Ma J, Zheng M, Shen Y, Wang L, Wang L, Zhu Y, Zhang X. Effects of cilostazol on thrombospondin-1 (TSP-1) expression changes in the myocardium of diabetic rats. J Int Med Res 2008; 36:800-9. [PMID: 18652777 DOI: 10.1177/147323000803600423] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Myocardial protective effects of the phosphodiesterase 3 inhibitor, cilostazol, in streptozotocin-induced diabetic rats were investigated. Four weeks after induction of diabetes, we measured thrombospondin-1 (TSP-1) expression in the left ventricular myocardium. Microstructural and ultrastructural changes were also analysed. Four weeks after the induction of diabetes there were significant differences in body weight and blood glucose between the control, diabetic and cilostazol-treated diabetic animals. TSP-1 expression was significantly increased in the myocardium of diabetic rats compared with the control group. Although significantly higher than the control group, TSP-1 expression was significantly lower in the cilostazol group compared with the diabetes group. There were obvious ultrastructural changes in the myocardium of diabetic rats, which were rarely seen in cilostazol-treated diabetic rats. In conclusion, this study provides experimental evidence that cilostazol treatment of diabetic rats effectively prevents pathological myocardial alterations, possibly via the down-regulation of TSP-1 expression.
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Affiliation(s)
- J Ma
- Department of Cardiovasology, The Second Affiliated Hospital School of Medicine, Zhejiang University, Hangzhou, China
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Hashimoto A, Miyakoda G, Hirose Y, Mori T. Activation of endothelial nitric oxide synthase by cilostazol via a cAMP/protein kinase A- and phosphatidylinositol 3-kinase/Akt-dependent mechanism. Atherosclerosis 2006; 189:350-7. [PMID: 16545819 DOI: 10.1016/j.atherosclerosis.2006.01.022] [Citation(s) in RCA: 163] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2005] [Revised: 01/05/2006] [Accepted: 01/25/2006] [Indexed: 11/29/2022]
Abstract
We investigated the effect of cilostazol on nitric oxide (NO) production in human aortic endothelial cells (HAEC). Cilostazol increased NO production in a concentration-dependent manner, and NO production was also increased by other cyclic-AMP (cAMP)-elevating agents (forskolin, cilostamide, and rolipram). Cilostazol increased intracellular cAMP level, and that effect was enhanced in the presence of forskolin. In Western blot analysis, cilostazol increased phosphorylation of endothelial nitric oxide synthase (eNOS) at Ser(1177) and of Akt at Ser(473) and dephosphorylation of eNOS at Thr(495). Cilostazol's regulation of eNOS phosphorylation was reversed by protein kinase A inhibitor peptide (PKAI) and by LY294002, a phosphatidylinositol 3-kinase (PI3K) inhibitor. Moreover, the cilostazol-induced increase in NO production was inhibited by PKAI, LY294002, and N(G)-nitro-l-arginine methyl ester hydrochloride (l-NAME), a NOS inhibitor. In an in vitro model of angiogenesis, cilostazol-enhanced endothelial tube formation, an effect that was completely attenuated by inhibitors of PKA, PI3K, and NOS. These results suggest that cilostazol induces NO production by eNOS activation via a cAMP/PKA- and PI3K/Akt-dependent mechanism and that this effect is involved in capillary-like tube formation in HAEC.
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Affiliation(s)
- Ayako Hashimoto
- Research Institute of Pharmacological & Therapeutical Development, Otsuka Pharmaceutical Co. Ltd., 463-10 Kagasuno, Kawauchi-cho, Tokushima 771-0192, Japan
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Omi H, Okayama N, Shimizu M, Fukutomi T, Nakamura A, Imaeda K, Okouchi M, Itoh M. Cilostazol inhibits high glucose-mediated endothelial-neutrophil adhesion by decreasing adhesion molecule expression via NO production. Microvasc Res 2004; 68:119-25. [PMID: 15313121 DOI: 10.1016/j.mvr.2004.05.002] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2003] [Indexed: 10/26/2022]
Abstract
OBJECTIVE Endothelial-neutrophil adhesion is crucial for vascular injury, the major cause of diabetic vascular complications. On the other hand, platelet aggregation inhibitors, frequently used for diabetic patients with intermittent claudication, have been shown to decrease the incidence of atherosclerosis-mediated diseases (acute myocardial infarction and stroke). However, whether these agents act directly on the endothelial reactions to hyperglycemia remains unclear. Therefore, we examined their direct effects on endothelial-neutrophil adhesion and expression of endothelial adhesion molecules induced by high glucose. METHODS AND RESULTS After human endothelial cells were cultured in high glucose medium, neutrophils from healthy volunteers were added and allowed to adhere for 30 min. Adhered neutrophils were quantified by measuring their myeloperoxidase (MPO) activities, and surface expression of endothelial adhesion molecules was determined with an enzyme immunoassay. Of the platelet aggregation inhibitors tested, only cilostazol significantly attenuated the adhesion through decreasing expression of intercellular adhesion molecule-1 (ICAM-1) and P-selectin. In addition, nitric oxide (NO) synthase inhibitors reduced the inhibitory effects of cilostazol, but a protein kinase C (PKC) activator did not. CONCLUSIONS Cilostazol may act directly on endothelial cells to inhibit expression of adhesion molecules and neutrophil adhesion induced by high glucose through increasing NO production.
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Affiliation(s)
- Hitoshi Omi
- Department of Internal Medicine and Bioregulation, Nagoya City University Graduate School of Medical Sciences, Nagoya 467-8601, Japan
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Ito C, Kusano E, Furukawa Y, Yamamoto H, Takeda SI, Akimoto T, Iimura O, Ando Y, Asano Y. Modulation of the erythropoietin-induced proliferative pathway by cAMP in vascular smooth muscle cells. Am J Physiol Cell Physiol 2002; 283:C1715-21. [PMID: 12419709 DOI: 10.1152/ajpcell.00143.2002] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We previously reported that erythropoietin (Epo) has a mitogenic effect on rat vascular smooth muscle cells (VSMC) and that activation of the mitogen-activated protein kinase (MAPK) cascade is an important mediator for Epo-induced mitogenesis. An increase in intracellular cAMP has an antiproliferative effect on VSMC. We therefore hypothesized that cAMP effectors inhibit Epo-induced MAPK activation in rat VSMC. When we exposed VSMC to recombinant human Epo (rHuEpo), DNA synthesis was increased. Forskolin (Fsk) or cilostazol (Cil) decreased the DNA synthesis stimulated by rHuEpo. Coincubation with Rp-cAMPS triethylamine canceled the suppression of DNA synthesis and MAPK activity by Fsk. Both rHuEpo and phorbol 12-myristate 13-acetate upregulated phosphorylations of MEK and MAPK. Pretreatment with Fsk inhibited these phosphorylations. Protein kinase C inhibitors also suppressed MEK and MAPK phosphorylations. Moreover, Fsk induced phosphorylation of Raf-1 at serine-259. These results indicated that cAMP inhibited Epo-induced MAPK activation and that this suppression might be regulated upstream or at Raf-1. The results also suggested that these agents, which could accumulate cAMP, might be protective for Epo-stimulated direct action.
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Affiliation(s)
- Chiharu Ito
- Division of Nephrology, Department of Internal Medicine, Jichi Medical School, Tochigi 329-0498, Japan
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