Miyuki Fukuda's research while affiliated with National Hospital Organization Minami Kyoto Hospital and other places

There are no drugs that prevent the growth of cerebral aneurysms or recanalization of aneurysm coil embolization. We have focused on the role of hemodynamics in cerebral aneurysm development and have shown that inhibition of P2X4 purinoceptor, required by vascular endothelial cells to sense blood flow, reduces the induction and growth of aneurysms in animals. A P2X4 purinoceptor inhibitor, paroxetine, is used clinically as an antidepressant. In this study, we therefore investigated the effects of paroxetine on aneurysm growth and postoperative recanalization of coiling. Among cases in the J-ASPECT Study registry, the comprehensive reimbursement database for inpatient care in Japan, we searched for patients taking paroxetine who were registered with a disease name of unruptured aneurysm or had undergone aneurysm coil embolization. Seventy-eight stroke facilities agreed to participate and 275 cases were identified as potentially eligible. Seventy-five enrolled cases met the eligibility criteria: 37 with unruptured aneurysms and 38 after coil embolization. These were compared with 396 controls with unruptured aneurysms and 308 post-coiling controls. Multivariate analysis showed that paroxetine significantly reduced the incidence of aneurysm growth (number of cases with growth/person/year; risk ratio 0.16, 95%CI 0.07–0.37) and the growth length rate (total growth length/person/year; risk ratio 0.46, 95%CI 0.25–0.79). Paroxetine significantly reduced recanalization in the year after coiling (odds ratio 0.22, 95%CI 0.05–0.98). This cohort study suggests that P2X4 inhibitors, including paroxetine, may be clinically applicable as prophylactic agents against rupture by inhibiting cerebral aneurysm growth, and as preventive drugs against postoperative recanalization.

Background It is difficult to predict the development of carotid stenosis by means of the known risk factors. Using a computational fluid dynamics analysis, we examined the hemodynamic risks for carotid stenosis, focusing on wall shear stress (WSS) disturbances. Methods In 59 cases of unilateral carotid stenosis, the plaque was removed from the original three-dimensional computed tomography angiographic images, and the vessel shape before stenosis was artificially reproduced. A multivariate regression analysis was performed to determine the associations between the degree of area stenosis and hemodynamic and morphological factors after adjustment for six known risk factors. Results Metrics for WSS disturbances were higher at and distal to a bifurcation in the carotid arteries after plaque removal compared with the normal carotid arteries, and metrics for WSS magnitudes were lower. In the plaque-removed arteries, the degree of stenosis was significantly negatively correlated with the ratio of stenotic to distal values of metrics for WSS disturbances and the diameter ratio of the external to common carotid artery, and positively correlated with the ratio of proximal to stenotic values of metrics for WSS magnitudes. Conclusions Rapid increases in WSS from the common carotid artery toward the bifurcation, rapid decreases in WSS disturbance from the bifurcation toward the internal carotid artery, and lower diameter ratio of the external to common carotid artery are more likely than other risk factors to cause future severe stenosis. In patients with these hemodynamic risks, underlying diseases should be controlled more strictly with imaging examinations at shorter intervals.

Background Rupture of a cerebral aneurysm is a major cause of life‐threatening subarachnoid hemorrhage. However, there are no effective therapeutic drugs for the treatment of aneurysms, partly because the pathogenesis of the aneurysm remains unresolved. Although chronic inflammation of the cerebral arterial wall plays an important role in aneurysm formation, it is not clear what triggers the inflammation. We previously reported that inhibition of the endothelial shear stress sensor, P2X4 purinoceptor, significantly reduces mRNA expressions of known inflammatory contributors to aneurysm formation, leading to suppression of aneurysm induction. We examined here whether inhibition of P2X4 has any influence on cerebral aneurysm ‘growth’ or not. Methods Sprague‐Dawley rats were subjected to cerebral aneurysm‐generating surgery with ligation of unilateral common carotid artery and renal hypertension. P2X4 purinoceptor inhibitor, paroxetine (8 mg/kg/day) was administered to rats. Three weeks after the surgery, the aneurysm size was examined with light microscopy, and protein expressions of contributors to aneurysm formation using Western blotting. Results The cerebral aneurysm‐inducing surgery induced an aneurysm in 100% of rats 2 weeks after the surgery. Application of paroxetine from 2 weeks after surgery led to a significant reduction in aneurysm size in the rats sacrificed 3 weeks after aneurysm‐inducing surgery (p=0.0145), indicating that paroxetine suppressed enlargement of formed aneurysms. The protein expression levels of known inflammatory contributors to aneurysm formation (MCP‐1, IL1ß, TNFα, iNOS, and COX‐2) were all significantly elevated in the rats that underwent the aneurysm‐inducing surgery compared to the non‐surgical group, and the values in the surgical group were all significantly decreased by paroxetine administration. Conclusion The data suggest that P2X4 is required for the cerebral aneurysm growth. Enhanced shear stress‐associated hemodynamic stress on the vascular endothelium may trigger the cerebral aneurysm enlargement. Since paroxetine has been used for human as an antidepressant, clinical use of this P2X4 purinoceptor inhibitor is expected as a novel therapy for cerebral aneurysms. Support or Funding Information This work was supported by the Japan Agency for Medical Research and Development (AMED) under grant no. JP15gm0810006h0301, a JSPS KAKENHI grant (no. 15K10323), and The Shimizu Foundation for Immunology and Neuroscience.

Objective: There are no effective therapeutic drugs for cerebral aneurysms, partly because the pathogenesis remains unresolved. Chronic inflammation of the cerebral arterial wall plays an important role in aneurysm formation, but it is not clear what triggers the inflammation. The authors have observed that vascular endothelial P2X4 purinoceptor is involved in flow-sensitive mechanisms that regulate vascular remodeling. They have thus hypothesized that shear stress-associated hemodynamic stress on the endothelium causes the inflammatory process in the cerebral aneurysm development. Methods: To test their hypothesis, the authors examined the role of P2X4 in cerebral aneurysm development by using P2X4-/- mice and rats that were treated with a P2X4 inhibitor, paroxetine, and subjected to aneurysm-inducing surgery. Cerebral aneurysms were induced by unilateral carotid artery ligation and renovascular hypertension. Results: The frequency of aneurysm induction evaluated by light microscopy was significantly lower in the P2X4-/- mice (p = 0.0488) and in the paroxetine-treated male (p = 0.0253) and female (p = 0.0204) rats compared to control mice and rats, respectively. In addition, application of paroxetine from 2 weeks after surgery led to a significant reduction in aneurysm size in the rats euthanized 3 weeks after aneurysm-inducing surgery (p = 0.0145), indicating that paroxetine suppressed enlargement of formed aneurysms. The mRNA and protein expression levels of known inflammatory contributors to aneurysm formation (monocyte chemoattractant protein-1 [MCP-1], interleukin-1β [IL-1β], tumor necrosis factor-α [TNFα], inducible nitric oxide synthase [iNOS], and cyclooxygenase-2 [COX-2]) were all significantly elevated in the rats that underwent the aneurysm-inducing surgery compared to the nonsurgical group, and the values in the surgical group were all significantly decreased by paroxetine administration according to quantitative polymerase chain reaction techniques and Western blotting. Although immunolabeling densities for COX-2, iNOS, and MCP-1 were not readily observed in the nonsurgical mouse groups, such densities were clearly seen in the arterial wall of P2X4+/+ mice after aneurysm-inducing surgery. In contrast, in the P2X4-/- mice after the surgery, immunolabeling of COX-2 and iNOS was not observed in the arterial wall, whereas that of MCP-1 was readily observed in the adventitia, but not the intima. Conclusions: These data suggest that P2X4 is required for the inflammation that contributes to both cerebral aneurysm formation and growth. Enhanced shear stress-associated hemodynamic stress on the vascular endothelium may trigger cerebral aneurysm development. Paroxetine may have potential for the clinical treatment of cerebral aneurysms, given that this agent exhibits efficacy as a clinical antidepressant.

Although rupture of cerebral aneurysms is a major cause of life‐threatening subarachnoid hemorrhage, there are no effective therapeutic drugs for the treatment of aneurysms, partly because the pathogenesis of the aneurysm remains unresolved. We hypothesize that shear stress‐related hemodynamics initiates cerebral aneurysm formation. To test this hypothesis, we examined here whether disruption or inhibition of the endothelial shear stress sensor, P2X4 purinoceptor, has any influence on expressions of known contributors to aneurysm formation or not. P2X4 purinoceptor deficient (P2X4 KO) mice and Sprague‐Dawley rats were subjected to cerebral aneurysm‐generating surgery with ligation of unilateral common carotid artery and renal hypertension. P2X4 purinoceptor inhibitor, paroxetine (8 mg/kg/day) was administered to rats after the surgery. The incidence of aneurysm formation was examined with light microscopy, and expressions of contributors to aneurysm formation using a quantitative real‐time PCR analysis and immunohistochemical examinations. The frequency of aneurysm induction in P2X4 KO mice was significantly lower than wild‐type mice ( p =0.018). In addition, paroxetine significantly attenuated the incidence of induced aneurysms in rats after aneurysm‐generating surgery (p=0.031). Expression levels of inflammatory contributors to aneurysm formation, COX‐2, TNFα, MCP‐1, IL1β, and iNOS, were significantly increased in rats after aneurysm‐inducing surgery than control non‐operated animals by a quantitative real‐time PCR analysis. Paroxetine significantly reduced the expression levels of all the contributors. These data suggest that shear sensing on the arterial endothelium initiates chronic inflammation in the arterial wall during cerebral aneurysm formation. Because paroxetine has been used for human as an antidepressant, clinical use of this P2X4 purinoceptor inhibitor is expected as a novel therapy for cerebral aneurysms. Support or Funding Information This work is supported by Japan Agency for Medical Research and development, AMED and JSPS KAKENHI Grant Number JP15K10323. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .

Background and purpose: It is thought that the cerebral aneurysm is caused by chronic inflammation of the arterial wall. However, it is still not clear what triggers the inflammation. We hypothesize that shear stress-related hemodynamics initiates cerebral aneurysm formation, and have reported that disruption of the endothelial shear stress sensor, P2X4 purinoceptor, significantly reduces cerebral aneurysm formation using knockout mice of the sensor. We examined here whether inhibition of P2X4 purinoceptor has any influence on expressions of inflammatory contributors to aneurysm formation or not. Methods: Sprague-Dawley rats (n = 61) were subjected to cerebral aneurysm-generating surgery with ligation of unilateral common carotid artery and renal hypertension, and the P2X4 purinoceptor inhibitor, paroxetine (8 mg/kg/day) was administered after the surgery for 3 weeks. The incidence of aneurysm formation was examined with light microscopy and expressions of inflammatory contributors to aneurysm formation using a quantitative real-time PCR analysis. Results: Paroxetine significantly attenuated the incidence of induced aneurysms in rats after aneurysm-generating surgery (p = 0.031, Wilcoxon/Kruskal-Wallis test). Expression levels of known inflammatory contributors to aneurysm formation, COX-2, TNFα, MCP-1, IL1β, and iNOS, were significantly increased in rats after aneurysm-inducing surgery than control non-operated animals by a quantitative real-time PCR analysis. Paroxetine significantly reduced the expression levels of COX-2, TNFα, MCP-1, IL1β, and iNOS (p = 0.0019, 0.0101, 0.0019, 0.0239, 0.0101, respectively). Conclusions: These data suggest that shear sensing on the arterial endothelium initiates chronic inflammation in the arterial wall during cerebral aneurysm formation. Because paroxetine has been used for human as an antidepressant, clinical use of this P2X4 purinoceptor inhibitor is expected as a novel therapy for cerebral aneurysms.

Figure S3 Effect of TASP0277308 on systemic blood pressure and peripheral monocyte or lymphocyte count. (A) Effect of TASP0277308 on peripheral lymphocyte count at 4 weeks after IA induction. Data represents mean ± SEM. Number of animals used is shown in parentheses. *, P < 0.05. (B) Systemic blood pressure of rats treated with each dose of TASP0277308 for 4 weeks after IA induction. SBP, MBP and DBP: systolic, mean and diastolic blood pressures, respectively. Data represents mean ± SEM. Number of animals used is shown in parentheses. (C) Effect of TASP0277308 on peripheral monocyte count at 4 weeks after IA induction. Data represents mean ± SEM. Number of animals used is shown in parentheses.

Figure S5 Effect of fingolimod on systemic blood pressure. Systemic blood pressure of rats treated with each dose of fingolimod for 4 weeks after IA induction. SBP, MBP and DBP: systolic, mean and diastolic blood pressures, respectively. Data represents mean ± SEM. Number of animals used is shown in parentheses.

Figure S4 Effect of KRP‐203 or BAF312 on systemic blood pressure. Systemic blood pressure of rats treated with KRP‐203 (0.01 mg·kg−1) or BAF312 (0.3 mg·kg−1) for 4 weeks after IA induction. SBP, MBP and DBP: systolic, mean and diastolic blood pressures, respectively. Data represents mean ± SEM. Number of animals used is shown in parentheses.