An oral administration of cilostazol before focal ischemia reduces the infarct volume with delayed cerebral blood flow increase in rats

Novel arylidene malonate derivative, KM-34, showed neuroprotective effects on in vitro and in vivo models of ischemia/reperfusion

Cerebral ischemia constitutes the most frequent type of cerebrovascular disease. The reduction of blood supply to the brain initiates the ischemic cascade starting from ionic imbalance to subsequent glutamate excitotoxicity, neuroinflammation and oxidative stress, eventually causing neuronal death. Previously, the authors have demonstrated the in vitro cytoprotective and antioxidant effects of a new arylidene malonate derivative, KM-34, against oxidizing agents like hydrogen peroxide, glutamate or Fe3+/ascorbate. Here, we examined for the first time the neuroprotective effect of KM-34 on ischemia/reperfusion models. In vitro, treatment with 10 and 50 μM KM-34 reduced the cellular death (propidium iodide incorporation) induced by oxygen glucose deprivation (OGD) in rat organotypic hippocampal slices cultures. In vivo, stroke was induced in male Wistar rats through middle cerebral artery occlusion (MCAO), followed by 23 h of reperfusion. KM-34 was orally administered 105 min after MCAO onset. We noticed that 1 mg/kg KM-34 reduced infarct volume and neurological score, and increased the latency to fall in the Hanging Wire test compared to vehicle-treated ischemic animals. While ischemic and sham-operated groups showed similar horizontal locomotor activity, vertical counts decreased after MCAO, suggesting that vertical movements are more sensitive to the ischemic injury. Treatment with KM-34 also alleviated the mitochondrial impairment (ROS generation, swelling and membrane potential dissipation) induced by transient MCAO but not significant alterations were found in oxidative stress parameters. Overall, the study provides preclinical evidences confirming the neuroprotective effects of a novel synthetic molecule and paved the way for future investigations regarding its therapeutic potential against brain ischemia/reperfusion injury.

Influence of Cilostazol on Changes in Cyclin D1 Expression in Cerebral Cortex of Rats with Chronic Cerebral Ischemia

The influence of cilostazol on learning and memory, and cyclin D1 expression in the cerebral cortex of rats with chronic cerebral ischemia were investigated. A chronic cerebral ischemia model was established using the permanent bilateral common carotid artery occlusion method (2VO), learning and memory capacity was detected using the Morris water maze, and expression changes in apoptosis regulating gene cyclin D1 were tested by RT-PCR. Results of the Morris water maze indicated that significant extensions were found in the escape latent period and swimming path of rats in the ischemia group (2VO group), learning and memory results in the cilostazol group was obviously superior compared to the 2VO group (P<0.05), and the expression of cyclin D1 was observed to increase in both the ischemia and cilostazol intervention groups at the 9th week of ischemia. A significant difference was observed, compared with the sham operation group (P<0.05), the expression level decreased in the ischemia group compared with the cilostazol group, and a significant difference was identified compared with the ischemia group (P<0.05). Cilostazol can reduce nerve function impairment and improve learning and memory functions by affecting changes in apoptosis regulating genes.

Neuroprotective Effects of Simvastatin and Cilostazol in L-Methionine-Induced Vascular Dementia in Rats

Vascular dementia (VaD) is a degenerative cerebrovascular disorder that leads to progressive decline in cognitive abilities and memory. Several reports demonstrated that oxidative stress and endothelial dysfunction are principal pathogenic factors in VaD. The present study was constructed to determine the possible neuroprotective effects of simvastatin in comparison with cilostazol in VaD induced by L-methionine in rats. Male Wistar rats were divided into four groups. Group I (control group), group II received L-methionine (1.7 g/kg, p.o.) for 32 days. The remaining two groups received simvastatin (50 mg/kg, p.o.) and cilostazol (100 mg/kg, p.o.), respectively, for 32 days after induction of VaD by L-methionine. Subsequently, rats were tested for cognitive performance using Morris water maze test then sacrificed for biochemical and histopathological assays. L-methionine induced VaD reflected by alterations in rats' behavior as well as the estimated neurotransmitters, acetylcholinesterase activity as well as increased brain oxidative stress and inflammation parallel to histopathological changes in brain tissue. Treatment of rats with simvastatin ameliorated L-methionine-induced behavioral, neurochemical, and histological changes in a manner comparable to cilostazol. Simvastatin may be regarded as a potential therapeutic strategy for the treatment of VaD. To the best of our knowledge, this is the first study to reveal the neuroprotective effects of simvastatin or cilostazol in L-methionine-induced VaD. Graphical Abstract ᅟ.

An experimental study of the effect of pre-operative administration of cilostazol on random skin flap survival in rats: double blinded randomized controlled trial

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.

Cilostazol for primary prevention of stroke in peripheral artery disease: a population-based longitudinal study in Taiwan

BACKGROUND

Clopidogrel, cilostazol, and aspirin were compared in terms of efficacy and safety for primary prevention of stroke in peripheral artery disease (PAD) patients.

METHODS

This retrospective cohort study analyzed data contained in the Taiwan National Health Insurance Bureau database for patients treated for PAD but not for stroke during 2002-2008. Patients were stratified according to treatment with aspirin, clopidogrel, cilostazol, or combined therapy. The primary efficacy and safety endpoints were stroke and hemorrhage.

RESULTS

Of the 931 patients enrolled in this study, 479 had received aspirin, 39 had received clopidogrel, 294 had received cilostazol alone, and 33 had received a cilostazol-based combined therapy. Compared to patients treated with aspirin, the patients treated with cilostazol had significantly lower all-stroke risk not only in the overall group (HR=0.66, 95% CI=0.48-0.90, p=0.0086), but also in the subgroup of patients with diabetes (HR=0.64, 95% CI=0.42-0.98, p=0.0394) and in the subgroup of patients with high cardiovascular risk (HR=0.66, 95% CI=0.46-0.95, p=0.0254). Additionally, compared to patients treated with aspirin, those treated with cilostazol did not have significantly more hemorrhagic events in the overall group, in the diabetes subgroup, or in the high cardiovascular risk subgroup. Clopidogrel, cilostazol-based combined therapy and aspirin did not significantly differ in terms of efficacy and hemorrhagic events.

CONCLUSION

Although this database study indicated that cilostazol therapy is an effective alternative treatment for primary prevention of stroke in PAD, further confirmation is needed in large, prospective, and randomized trials.

Intracerebroventricular injection of HAMI 3379, a selective cysteinyl leukotriene receptor 2 antagonist, protects against acute brain injury after focal cerebral ischemia in rats

Cysteinyl leukotrienes (CysLTs) induce inflammatory responses by activating their receptors, CysLT(1)R and CysLT(2)R. We recently reported that CysLT(2)R is involved in neuronal injury, astrocytosis and microgliosis after focal cerebral ischemia in rats. Here, we determined whether HAMI 3379, a selective CysLT(2)R antagonist, protects against acute brain injury after focal cerebral ischemia in rats. We induced transient focal cerebral ischemia by 30 min of middle cerebral artery occlusion (MCAO), followed by 24h of reperfusion. HAMI 3379 (1, 10 or 100 ng) was injected intracerebroventricularly (i.c.v.) 30 min before MCAO, and the CysLT(1)R antagonist pranlukast (0.1mg/kg, i.p.) was used as a positive control. HAMI 3379 at 10 and 100 ng (but not at 1 ng) attenuated the neurological deficits, and reduced infarct volume, brain edema, IgG exudation, neuronal degeneration and neuronal loss. This protective effect was similar to that of pranlukast. Thus, HAMI 3339 at 10-100 ng i.c.v. is neuroprotective against acute brain injury after focal cerebral ischemia in rats. These findings suggest therapeutic potential for CysLT(2)R antagonists in the treatment of ischemic stroke.

Cilostazol in Acute Ischemic Stroke Treatment (CAIST Trial): a randomized double-blind non-inferiority trial

BACKGROUND

Aspirin is a proven antiplatelet agent in acute ischemic stroke, and there are no current guidelines for other antiplatelet treatments. We aimed to compare the efficacy and safety of cilostazol with aspirin in acute stroke.

METHODS

Patients with measurable neurological deficits (NIHSS score ≤15) within 48 h of onset were randomly assigned to cilostazol (200 mg/day) or aspirin (300 mg/day) for 90 days. The primary endpoint was a modified Rankin Scale (mRS) score of 0-2 at 90 days. Cardiovascular events, bleeding complications, and other functional outcomes were also assessed. Statistical analysis was carried out by intention-to-treat and per-protocol bases. This trial is registered with ClinicalTrials.gov (NCT00272454).

RESULTS

In total, 458 patients were enrolled (mean age of 63 years, median NIHSS of 3), and mRS at 90 days was obtained in 447 patients. The primary endpoint was achieved in 76% (173/228) of those randomized to cilostazol and in 75% (165/219) assigned to aspirin, which supported the pre-specified non-inferiority of cilostazol to aspirin (95% CI of proportion difference: -6.15 to 7.22%, p = 0.0004). These results were also supported by per-protocol analysis (p = 0.045). Cardiovascular events occurred in 6 patients (3%) treated with cilostazol, and in 9 patients (4%) treated with aspirin (p = 0.41). Adverse events were more common in cilostazol-treated patients during the trial (91 vs. 85%, p = 0.055), while the frequencies of bleeding complications (cilostazol 11%, aspirin 13%, p = 0.43) or drug discontinuation (cilostazol 10%, aspirin 7%, p = 0.32) were not different.

CONCLUSION

Cilostazol is feasible in acute ischemic stroke, and comparable to aspirin in its efficacy and safety.

Phosphodiesterases as targets for intermittent claudication

Intermittent claudication (IC) is one of the most frequent forms of lower extremity peripheral arterial disease (PAD) and is most commonly caused by arterial atherosclerosis. Its clinical manifestation includes fatigue, discomfort, or pain occurring in limb muscles due to exercise-induced ischemia, thus limiting the ability of IC patients to walk and exercise. In addition to lifestyle changes (diet, exercise, and smoking cessation), pharmacological treatments are needed. Pathologically, atherosclerotic lesions cause a mismatch in oxygen supply and metabolic demand in the leg muscles during walking/exercise. This subjects the muscles to repeated ischemia and reperfusion injury that can alter structure and oxidative metabolism, resulting in insufficient utilization of oxygen supply. Despite extensive research efforts, cilostazol and pentoxifylline are the only drugs indicated for relieving the symptoms of IC, with cilostazol demonstrating significant improvement in walking distance and quality of life in these patients. Originally developed as a PDE3 inhibitor, cilostazol was later found to have several other pharmacological actions, and its success has been attributed to its multifactorial actions on platelets, endothelium, smooth muscle, and lipid profiles. Using cilostazol as an example, we discuss the rationales and pitfalls of targeting PDEs in IC, and potential strategies for the development of new and more effective pharmacological treatments.

Alterations in nitric oxide and endothelin-1 bioactivity underlie cerebrovascular dysfunction in ApoE-deficient mice

Hypercholesterolemia is associated with decreased nitric oxide (NO) bioavailability and endothelial dysfunction, a phenomenon thought to have a major role in the altered cerebral blood flow evident in stroke. Therefore, strategies that increase endothelial NO production have potential utility. Vascular reactivity of the middle cerebral artery (MCA) from C57BL/6J wild-type (WT) mice, apolipoprotein-E knockout (ApoE(-/-)) mice, and mice treated with the phosphodiesterase inhibitor cilostazol (100 mg/kg) was analyzed using the tension myograph. Contractile responses to endothelin-1 were significantly enhanced in MCA from ApoE(-/-) mice compared with WT mice (P<0.01), an effect absent in cilostazol-treated ApoE(-/-) mice. Acetylcholine-induced relaxation (which is entirely NO-dependent) was significantly impaired in MCA of ApoE(-/-) mice compared with WT mice (P<0.05), again an effect prevented by cilostazol treatment. Endothelial NOS phosphorylation at Ser(1179) was decreased in the aorta of ApoE(-/-) mice compared with WT mice (P<0.05), an effect normalized by cilostazol. Taken together, our data suggest that the endothelial dysfunction observed in MCA associated with hypercholesterolemia is prevented by cilostazol, an effect likely due to the increase in eNOS phosphorylation and, therefore, activity.