Fumihiko Nishimura

Potential Use of Embryonic Stem Cells for the Treatment of Mouse Parkinsonian Models: Improved Behavior by Transplantation of In Vitro Differentiated Dopaminergic Neurons from Embryonic Stem Cells

Background and Aims. The purpose of the present study was to examine the efficacy of transplantation of mouse embryonic‐stem‐(ES)‐cell‐derived tyrosine hydroxylase‐positive (TH+) cells into Parkinsonian mice using behavioral tests and immunohistochemical evaluation.

Cotransplantation of mouse embryonic stem cells and bone marrow stromal cells following spinal cord injury suppresses tumor development.

Embryonic stem (ES) cells are a potential source for treatment of spinal cord injury (SCI). Although one of the main problems of ES cell-based cell therapy is tumor formation, there is no ideal method to suppress tumor development. In this study, we examined whether transplantation with bone marrow stromal cells (BMSCs) prevented tumor formation in SCI model mice that received ES cell-derived grafts containing both undifferentiated ES cells and neural stem cells. Embryoid bodies (EBs) formed in 4-day hanging drop cultures were treated with retinoic acid (RA) at a low concentration of 5 × 10–9 M for 4 days, in order to allow some of the ES cells to remain in an undifferentiated state. RA-treated EBs were enzymatically digested into single cells and used as ES cell-derived graft cells. Mice transplanted with ES cell-derived graft cells alone developed tumors at the grafted site and behavioral improvement ceased after day 21. In contrast, no tumor development was observed in mice cotransplanted with BMSCs, which also showed sustained behavioral improvement. In vitro results demonstrated the disappearance of SSEA-1 expression in cytochemical examinations, as well as attenuated mRNA expressions of the undifferentiated markers Oct3/4, Utf1, Nanog, Sox2, and ERas by RT-PCR in RA-treated EBs cocultured with BMSCs. In addition, MAP2-immunopositive cells appeared in the EBs cocultured with BMSCs. Furthermore, the synthesis of NGF, GDNF, and BDNF was confirmed in cultured BMSCs, while immunohistochemical examinations demonstrated the survival of BMSCs and their maintained ability of neurotrophic factor production at the grafted site for up to 5 weeks after transplantation. These results suggest that BMSCs induce undifferentiated ES cells to differentiate into a neuronal lineage by neurotrophic factor production, resulting in suppression of tumor formation. Cotransplantation of BMSCs with ES cell-derived graft cells may be useful for preventing the development of ES cell-derived tumors.

Transplantation of embryonic stem cell-derived neural stem cells for spinal cord injury in adult mice

Abstract Aims: To investigate the efficacy of embryonic stem cell-derived neural stem cells (NSCs) for spinal cord injury (SCI) in mice and whether a combination treatment with thyroid hormone provides a more effective ES cell-based therapy. Methods: Nestin-positive NSCs were induced from undifferentiated mouse ES cells by a step-by-step culture and used as grafts. Thirty-six mice were subjected to an SCI at Th10 and divided into three groups of 12. Graft cells were transplanted into the injury site 10 days after injury. Group 1 mice were left under observation without receiving graft cells, while mice in Group 2 received 2 × 104 graft cells, and those in Group 3 received 2 × 104 graft cells and were treated with a continuous intraperitoneal injection of thyroxin using osmotic mini-pumps. Behavioral improvement was assessed by a scoring system throughout the experimental period until post-transplantation day (PD) 28. Results: Mice in Groups 2 and 3 demonstrated an improved behavioral function, as compared to those in Group 1 after PD 14. There was no significant difference in behavioral recovery between Groups 2 and 3. Conclusions: Transplantation of ES-NSCs into the injury site was effective for SCI, while thyroxine did not deliver additional effectiveness.

Intraventricular transplantation of embryonic stem cell-derived neural stem cells in intracerebral hemorrhage rats

Abstract In the present study, we attempted to explore cell transplantation therapy for intracerebral hemorrhage (ICH) using embryonic stem (ES) cells. Collagenase-induced ICH rats were used as model animals. Mouse ES cells were differentiated into nestin-positive neural stem cells in vitro by alltrans retinoic acid (ATRA). ATRA-treated ES cells (105) were transplanted into the lateral ventricle in the hemisphere contralateral to the hemorrhage 7 days after collagenase infusion. Twenty-eight days after transplantation, ES-derived neurons and astrocytes were observed around the hematoma cavities of the brain in all of the ten rats receiving grafts. Graft-derived neurons were found in the subependymal area of the lateral ventricle as cellular nodules. Although one of the ten rats receiving grafts showed uncontrolled growth of astroglia derived from the ES cells, intraventricular transplantation of ATRA-treated ES cells is an effective delivery system of neuronal lineage-committed progenitor cells toward the site of ICH.

Significance of the Hemorrhagic Site for Recurrent Bleeding: Prespecified Analysis in the Japan Adult Moyamoya Trial

Background and Purpose— The primary results of the Japan Adult Moyamoya Trial revealed the statistically marginal superiority of bypass surgery over medical treatment alone in preventing rebleeding in moyamoya disease. The purpose of this analysis is to test the prespecified subgroup hypothesis that the natural course and surgical effects vary depending on the hemorrhagic site at onset. Methods— The hemorrhagic site, classified as either anterior or posterior, was the only stratifying variable for randomization. Statistical analyses were focused on the assessment of effect modification according to the hemorrhagic site and were based on tests of interaction. Results— Of 42 surgically treated patients, 24 were classified as anterior hemorrhage and 18 as posterior hemorrhage; of 38 medically treated patients, 21 were classified as anterior and 17 as posterior. The hazard ratio of the primary end points (all adverse events) for the surgical group relative to the nonsurgical group was 0.07 (95% confidence interval, 0.01–0.55) for the posterior group, as compared with 1.62 (95% confidence interval, 0.39–6.79) for the anterior group (P=0.013 for interaction). Analysis within the nonsurgical group revealed that the incidence of the primary end point was significantly higher in the posterior group than in the anterior group (17.1% per year versus 3.0% per year; hazard ratio, 5.83; 95% confidence interval, 1.60–21.27). Conclusions— Careful interpretation of the results suggests that patients with posterior hemorrhage are at higher risk of rebleeding and accrue greater benefit from surgery, subject to verification in further studies. Clinical Trial Registration— URL: http://www.umin.ac.jp/ctr/index.htm. Unique identifier: C000000166.

Early Inhibition of Natriuresis Suppresses Symptomatic Cerebral Vasospasm in Patients with Aneurysmal Subarachnoid Hemorrhage

Background: Hyponatremia is a common complication occurring in one third of patients after subarachnoid hemorrhage (SAH). One mechanism that likely mediates the development of hyponatremia in SAH is cerebral salt wasting syndrome (CSWS), which induces natriuresis and reduces total blood volume, resulting in a risk of symptomatic vasospasm (SVS). The mineral corticoid fludrocortisone acetate enhances sodium reabsorption in the renal distal tubules and may help prevent post-SAH hyponatremia. However, management with fludrocortisone acetate is ineffective if hyponatremia is advanced, because CSWS and subsequent SVS develop rapidly. Therefore, an additional earlier marker is required to predict the development of hyponatremia for the initiation of immediate treatment in select patients. However, no conclusive evidence exists showing that hyponatremia influences the risk of SVS, and no standard treatment protocol exists for treating hyponatremia in patients with SAH. This study was undertaken to evaluate whether selective early treatment of hyponatremia prevents SVS in patients with increased urinary sodium excretion in the early phase following SAH. Methods: A total of 103 patients with aneurysmal SAH were managed for a postoperative electrolyte disorder after aneurysmal clipping or coil embolization. Between 2004 and 2007 (period 1), 54 patients started treatment to correct the electrolyte disorder after hyponatremia had occurred. Between 2007 and 2011 (period 2), 49 patients were prospectively subjected to sodium replacement treatment according to their daily sodium balance, and inhibition of natriuresis with fludrocortisone acetate was initiated just after an increase in urinary sodium excretion >300 mEq/day. The occurrence of hyponatremia, SVS, and outcomes were compared between the two periods. Results: Hyponatremia was observed in 14 patients (26%) in period 1 and 7 patients (14%) in period 2. The incidence of fludrocortisone acetate administration was significantly higher, and initiation of electrolyte correction was significantly earlier, in period 2 patients. We observed a significant difference in the frequency of SVS, which occurred in 10 patients (18.5%) in period 1 and 3 patients (6.1%) in period 2. Both urinary sodium excretion and urine volume at day 7 were significantly different between the two periods. However, no significant difference was observed in overall outcome between the two periods. Conclusions: Early inhibition of natriuresis with fludrocortisone acetate before the occurrence of hyponatremia prevented SVS after aneurysmal SAH. Increased urinary sodium excretion in the early phase of SAH is a good indicator for the initiation of electrolyte correction with fludrocortisone acetate.

Treatment of Parkinson's disease model mice with allogeneic embryonic stem cells: necessity of immunosuppressive treatment for sustained improvement.

Abstract Objective: The purpose of the present study was to examine the efficacy of transplantation of mouse embryonic stem (ES) into Parkinsons disease (PD) model mice as well as the necessity of immunosuppression in allogeneic donor-host combinations. Materials and methods: ES cells, derived from SvJ129 strain mice, were differentiated into tyrosine hydroxylase (TH)-positive neurons in vitro by an embryoid body (EB)-based multistep differentiation method and used as graft cells for PD mice, which were prepared by injection of 6-hydroxydopamine (OHDA) into C57BL/6, BALB/c and C3H/HeN strains. Mice from each strain were divided into Groups 1–3. Four weeks after the 6-OHDA injection, Group 1 received phosphate-buffered saline in the striatum wounds, while Group 2 received 2 × 104 graft cells, and Group 3 mice received 2 × 104 graft cells and were also treated with cyclosporine A. Results: Apomorphine-induced rotational behavior was improved in Groups 2 and 3, but not in Group 1. However, the behavioral improvement ceased later in Group 2, whereas sustained improvement was observed in Group 3 throughout the 8 week observation period after transplantation. ES-derived TH+ cells were found at the grafted sites at the end of the experiment in Groups 2 and 3, and tended to be more abundant in Group 3. Conclusion: Intra-striatum transplantation of ES-derived dopaminergic neurons was effective in treating PD mice, even in allogeneic donor-host combinations. Immunosuppressive treatment did not have an effect on initial behavioral restoration after transplantation; however, it was necessary for sustained improvement over a prolonged period.

Discriminant analysis prediction of the need for ventriculoperitoneal shunt after subarachnoid hemorrhage.

Shunt operations have conventionally been performed to deal with normal-pressure hydrocephalus after subarachnoid hemorrhage. The indication and timing of shunt operations are often based on clinical symptoms and head computed tomography findings, and the early identification of the need for such surgery would be advantageous. The present study examined whether this need could be predicted solely on the basis of data collected on patient admission. A total of 120 consecutive patients with subarachnoid hemorrhage who underwent radical surgery for aneurysm were analyzed for potential risk factors for the onset of hydrocephalus that could be investigated on admission. Statistically significant differences between those patients who required a shunt operation and those who did not were found in terms of age, Hunt and Kosnik grade on first visit, Glasgow Coma Scale score on first visit, Fisher group, presence/absence of hydrocephalus, presence/absence of intraventricular hemorrhage, and transverse dimension of the third ventricle and distance between lateral ventricles measured by head computed tomography scan on first visit. Discriminant analysis performed on these 8 variables yielded a single discriminant function with a high sensitivity of 85.3% and a high specificity of 87.2%. Our findings indicate that the discriminant function is capable of predicting the need for the shunt operation soon after patient admission and can shorten the waiting time for the operation, and hence can be expected to contribute to decreasing the length of hospital stay in these patients.

Expression of ciliary neurotrophic factor (CNTF), CNTF receptor alpha (CNTFR-α) following experimental intracerebral hemorrhage in rats

Ciliary neurotrophic factor (CNTF) is known as a neuro-survival factor in the developing and developed CNS, as well as in the CNS following injury. However, little is known about the expression of CNTF or that of its receptor (CNTFR-alpha) in cases of intracerebral hemorrhage (ICH). We investigated the temporal and spatial profiles of CNTF and CNTFR-alpha expression using a collagenase-induced ICH rat model. CNTF expression was up-regulated from the day following ICH induction and reached a peak level at 5 to 14 days, with increased expression observed in brain tissue surrounding the hematoma lesion and white matter structures in association with astroglial proliferation. Further, CNTFR-alpha was transiently expressed in the cerebral cortex surrounding the hematoma, with a peak at 5 days. Administration of exogenous CNTF into the lesion following initiation of ICH resulted in a prolonged expression of CNTFR-alpha on cortical neurons neighboring the hematoma. Our findings suggest differential regulation of CNTF and CNTFR-alpha, and the possibility of a therapeutic strategy using CNTF administration for ICH.

Platelet inhibition by adjunctive cilostazol suppresses the frequency of cerebral ischemic lesions after carotid artery stenting in patients with carotid artery stenosis

OBJECTIVE Optimal platelet inhibition is an important therapeutic adjunct in patients with carotid artery stenosis undergoing carotid artery stenting (CAS). Clopidogrel resistance is associated with increased periprocedural thromboembolic complications from neurovascular stent placement procedures. The addition of cilostazol to dual antiplatelet therapy (DAT) has been reported to reduce platelet reactivity and to improve clinical outcomes after percutaneous coronary intervention. This study was undertaken to evaluate the impact of adjunctive cilostazol in patients with CAS. METHODS Platelet function was assessed by light transmittance aggregometry using the VerifyNow assay. Sixty-four consecutive patients who underwent CAS received standard DAT, clopidogrel (75 mg daily), and aspirin (100 mg daily) more than 4 weeks before the procedure. From 2010 to 2011 (period I), 28 patients underwent CAS under standard DAT. From 2011 to 2013 (period II), 36 patients prospectively had preoperative assessment of platelet function, and 13 patients with clopidogrel resistance received adjunctive cilostazol (200 mg daily) in addition to standard DAT. The incidence of new ipsilateral ischemic lesions on diffusion-weighted imaging a day after CAS and ischemic or hemorrhagic events within 30 days was assessed. RESULTS Clopidogrel resistance was indentified in 12 patients (43%) in period I and 13 patients (36%) in period II (P = .615). In period II, the addition of cilostazol significantly decreased P2Y12 reaction units and % inhibition (P = .006 and P = .005, respectively), and there was a significant difference in P2Y12 reaction units between the two periods. New ipsilateral ischemic lesions were significantly decreased in period II (2/36 patients) compared with period I (7/28 patients; P = .034); however, there was no significant difference in hemorrhagic and thromboembolic events between the two periods. CONCLUSIONS Adjunctive cilostazol (triple antiplatelet therapy) in clopidogrel-resistant patients reduces the rate of clopidogrel resistance and suppresses new ischemic lesions without hemorrhagic complications, as compared with standard DAT. Antiplatelet management based on the evaluation of antiplatelet resistance would be required for prevention of perioperative thromboembolic complications in CAS.