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Kazuki Kobayashi,
Takao Yasuhara,
Takashi Agari,
Kenichiro Muraoka,
Masahiro Kameda,
Wen Ji Yuan,
Hitoshi Hayase,
Toshihiro Matsui,
Yasuyuki Miyoshi,
Tetsuro Shingo,
Isao Date
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ABSTRACT: We established a PC12 cell line (PC12TH Tet-Off) in which human tyrosine hydroxylase (TH) expression can be negatively controlled by Doxycycline (Dox). First, dopamine (DA)-secretion from PC12TH Tet-Off cells was controlled by Dox-administration in a dose-responsive manner ranging from 0 to 100 ng/ml for 70 days in vitro. Furthermore, Parkinson's disease model of rats receiving encapsulated PC12TH Tet-Off cells displayed a significant decrease of dopamine concentration in the cerebrospinal fluid (CSF) and increase of the number of apomorphine-induced rotations by Dox-administration, as compared to transplanted rats without Dox-administration, although the significant decrease of the reduction ratio of DA concentration in the CSF with Dox-administration was recognized over time. At 2 months post-implantation, concentration of dopamine in the implanted striatum and from the retrieved capsules demonstrated that the control of DA-secretion could be partially achieved for 2 months in vivo. Our results support both the value of cell therapy using Tet-Off system and the technique of encapsulation might be a feasible option for Parkinson's disease especially in resolving the problem of dopamine oversupply in the future, although a more efficient way to control DA-secretion with quicker regulation and much titration of dose should be explored before clinical application.
Brain Research 09/2006; 1102(1):1-11. · 2.73 Impact Factor
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Akimasa Yano,
Tetsuro Shingo,
Akira Takeuchi,
Takao Yasuhara, Kazuki Kobayashi,
Kazuya Takahashi,
Kenichiro Muraoka,
Toshihiro Matsui,
Yasuyuki Miyoshi,
Hirofumi Hamada,
Isao Date
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ABSTRACT: The authors evaluated the neuroprotective and angiogenic effects of a continuous and low-dose infusion of vascular endothelial growth factor (VEGF)-165 on cerebral ischemia in rats.
The authors introduced VEGF complementary (c)DNA into baby hamster kidney (BHK) cells and established a cell line that produces human VEGF165 (BHK-VEGF). The BHK-VEGF cells and BHK cells that had been transfected with an expression vector that did not contain human VEGF165 cDNA (BHK-control) were encapsulated. Both capsules were implanted into rat striata. Six days after capsule implantation, the right middle cerebral artery (MCA) was occluded. Some animals were killed 24 hours after occlusion to measure the volume of the resulting infarct and to perform immunohistochemical studies. Other animals were used for subsequent behavioral studies 1, 7, and 14 days after MCA occlusion. The encapsulated BHK-VEGF cell grafts significantly reduced the volume of the infarct and the number of apoptotic cells in the penumbral area when compared with the effect of the BHK-control cell capsule. In addition, angiogenesis and gliogenesis significantly increased in the region around the capsule in animals that received BHK-VEGF cell capsules without an increase in focal cerebral blood flow; this did not occur in animals that received the BHK-control cell capsule. In behavioral studies rats that received the BHK-VEGF cell capsule displayed significant recovery while participating in the accelerating rotarod test after stroke.
Continuous intracerebral administration of low-dose VEGF165 through encapsulated grafts of VEGF-producing cells produces neuroprotective and angiogenic effects. These effects improve subsequent motor function.
Journal of Neurosurgery 08/2005; 103(1):104-14. · 2.96 Impact Factor
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Takao Yasuhara,
Tetsuro Shingo,
Kenichiro Muraoka, Kazuki Kobayashi,
Akira Takeuchi,
Akimasa Yano,
Yuan Wenji,
Masahiro Kameda,
Toshihiro Matsui,
Yasuyuki Miyoshi,
Isao Date
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ABSTRACT: Glial cell line-derived neurotrophic factor (GDNF) has been shown to confer neuroprotective effects on dopaminergic neurons. The authors investigated the effects of GDNF on 6-hydroxydopamine (6-OHDA)-treated dopaminergic neurons in vitro and in vivo.
First, the authors examined how 1, 10, or 100 ng/ml of GDNF, administered to cells 24 hours before, simultaneously with, or 2 or 4 hours after 6-OHDA was added, affected dopaminergic neurons. In a primary culture of E14 murine ventral mesencephalic neurons, earlier treatment with the higher dosage of GDNF suppressed 6-OHDA-induced loss of dopaminergic neurons better than later treatment. Next, the authors examined whether continuous infusion of GDNF at earlier time points would demonstrate a greater neuroprotective effect in a rat model of Parkinson disease (PD). They established a human GDNF-secreting cell line, called BHK-GDNF, and encapsulated the cells into hollow fibers. The encapsulated cells were unilaterally implanted into the striatum of adult rats 1 week before; simultaneously with; or 1, 2, or 4 weeks after 6-OHDA was given to induce lesions of the same striatum. With the earlier transplantation of a BHK-GDNF capsule, there was a significant reduction in the number of amphetamine-induced rotations displayed by the animals. Rats that had received earlier implantation of BHK-GDNF capsules displayed more tyrosine hydroxylase-positive neurons in the substantia nigra pars compacta and a tendency for glial proliferation in the striatum.
These neuroprotective effects may be related to glial proliferation and signaling via the GDNF receptor alpha1. The results of this study support a role for this grafting technique in the treatment of PD.
Journal of Neurosurgery 02/2005; 102(1):80-9. · 2.96 Impact Factor
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ABSTRACT: Vascular endothelial growth factor (VEGF) has previously been shown to display neuroprotective effects following ischemia, suggesting that VEGF may potentially be applied as a neuroprotective agent for the treatment of other neurological diseases. In this study, we investigated the neuroprotective capacity of VEGF in a model of Parkinson's disease. VEGF was found to be neuroprotective against cell death of primary E14 murine ventral mesencephalic neurons induced by 6-hydroxydopamine (6-OHDA) treatment in vitro. Further, rats receiving a continuous infusion of VEGF into the striatum via encapsulated hVEGF-secreting cells (baby hamster kidney-VEGF) displayed a significant decrease in amphetamine-induced rotational behavior and a significant preservation of tyrosine hydroxylase-positive neurons and fibers compared with control animals. VEGF likely functions via direct mechanisms by signaling through the neuropilin receptor expressed upon dopaminergic neurons in response to 6-OHDA treatment. Further, VEGF is likely to promote neuroprotection indirectly by activating the proliferation of glia and by promoting angiogenesis. Our results support a potential neuroprotective role for VEGF in the treatment of Parkinson's disease.
European Journal of Neuroscience 04/2004; 19(6):1494-504. · 3.63 Impact Factor
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ABSTRACT: This study was conducted to evaluate the effects of grafting encapsulated basic fibroblast growth factor (bFGF)-secreting cells in rat brains subjected to ischemic injury.
Two cell lines were used for encapsulated grafting in this experiment, namely, a bFGF-secreting cell line established by genetic manipulation of baby hamster kidney (BHK) cells, and a naive BHK cell line. Forty-seven Sprague-Dawley rats were used in this experiment. The animals were divided into the following three groups: those receiving grafts of encapsulated bFGF-secreting cells (BHK-bFGF group); those with grafts of encapsulated naive BHK cells (naive BHK group); and those with no grafts (control group). The authors implanted encapsulated cells into the right striatum of host rats in the BHK-bFGF and naive BHK groups. Six days after grafting, the host and control animals underwent permanent right middle cerebral artery occlusion (MCAO) with an intraluminal suture procedure. The infarct volume was evaluated using 2,3,5-triphenyltetrazolium chloride staining and computerized image analysis 24 hours after MCAO. Fragmentations of DNA in the host brains were analyzed using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling 12 hours after MCAO. The authors found that the infarct volume in the BHK-bFGF group was reduced by approximately 30% compared with that in the naive BHK and control groups. In the ischemic penumbral area, the number of apoptotic cells in the BHK-bFGF group was significantly decreased compared with that in the other groups.
The grafting of encapsulated BHK bFGF-secreting cells protected the brain from ischemic injury. Encapsulation and grafting of genetically engineered cells such as bFGF-secreting cells is thus thought to be a useful method for protection against cerebral ischemia.
Journal of Neurosurgery 01/2004; 99(6):1053-62. · 2.96 Impact Factor
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ABSTRACT: The PC12 cells are well known for their ability to secrete dopamine and levodopa. In multiple animal mode encapsulated PC12 cells have been shown to ameliorate parkinsonian symptoms when transplanted into the striatum; technique is expected to be effective clinically as well. The present study was performed using nonhuman primates to ensure that the transplantation of encapsulated PC12 cells is likely to be both safe and effective in human clinical trials.
Unencapsulated or encapsulated PC12 cells were implanted into the brains of Japanese monkeys (Macaca fuscata). Histological and immunocytochemical analyses were performed 1, 2, 4, and 8 weeks posttransplantation on the unencapsulated cells and 2, 4, and 8 weeks after transplantation on the encapsulated cells. The survival of the PC12 cells inside the capsule was determined by measuring the amounts of dopamine and levodopa released from the capsules a removal from the striatum. Magnetic resonance imaging was performed in both unencapsulated and encapsulated PC12 cell-grafted groups. Due to the immunological reaction of the host brain no unencapsulated PC12 cells remained in the grafted area 8 weeks after transplantation. On the contrary, encapsulated PC12 cells retrieved from the host brain continued to release dopamine and levodopa even 8 weeks after implantation. The host's reaction to the PC12-loaded capsule was much weaker than that to the unencapsulated PC12 cells.
These results suggest that the transplantation of encapsulated PC12 cells could be a safe and effective treatment modality for Parkinson disease in human patients.
Journal of Neurosurgery 05/2003; 98(4):874-81. · 2.96 Impact Factor
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ABSTRACT: To evaluate a potential neuroprotective role for vascular endothelial growth factor (VEGF) during ischemia, we grafted encapsulated VEGF-secreting cells into the brain parenchyma of a rat model of stroke. A genetically modified VEGF-secreting cell line (50–100 ng/106 cells/day) was established, and when encapsulated, these cells produced VEGF in a continuous and stable fashion for at least 2 months (30–50 ng/capsule/day). Recombinant human VEGF was delivered into the rat striatum at approximately the same delivery rate as that observed by the encapsulated cells (35 or 70 ng/day) for 6 days using a mini-osmotic pump. Six days after infusion, host animals received transient middle cerebral artery occlusion by the intraluminal suture technique. We found that the infarct volume in the VEGF infusion group was reduced by approximately 40% compared with vehicle infusion group. Furthermore, VEGF infusion caused significantly increased cerebral angiogenesis in the ischemic brain. In the penumbra area, the number of apoptotic cells in the VEGF infusion group was decreased significantly compared with that in vehicle group. These data show that the administration of a low-dose of VEGF into the parenchyma has both angiogenic and neuroprotective effects in the ischemic brain. Encapsulation and the grafting of genetically modified VEGF-secreting cells may be considered as a potentially effective therapy for the treatment of stroke in the future.
International Congress Series 1252:483-487.
