1. ¹Department of Neurosurgery, Osaka Medical College, Takatsuki, Osaka, Japan
2. ²Department of Neurosurgery, Pu Nan Hospital, Shanghai, People's Republic of China
3. ³First Department of Internal Medicine, Osaka Medical College, Takatsuki, Osaka, Japan
4. ⁴Division of Molecular Regenerative Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
5. ⁵Department of Anatomy and Neurobiology, Kyoto University Graduate School of Medicine, Kyoto, Japan
6. ⁶Department of Anatomy and Biology, Osaka Medical College, Takatsuki, Osaka, Japan
7. ⁷Department of Molecular Pathology in Windeyer Institute of Medical Sciences of University College, London, UK

Correspondence: Dr S-I Miyatake and Dr T Kuroiwa, Department of Neurosurgery, Graduate School of Medicine, Osaka Medical College, 2-7 Daigakumachi, Takatsuki City, Osaka 569-8686, Japan. E-mail: neu070@poh.osaka-med.ac.jp

Received 22 August 2005; Revised 29 November 2005; Accepted 5 December 2005; Published online 18 January 2006.

Abstract

Occlusive cerebrovascular disease leads to brain ischemia that causes neurological deficits. Here we introduce a new strategy combining mesenchymal stromal cells (MSCs) and ex vivo hepatocyte growth factor (HGF) gene transferring with a multimutated herpes simplex virus type-1 vector in a rat transient middle cerebral artery occlusion (MCAO) model. Gene-transferred MSCs were intracerebrally transplanted into the rats' ischemic brains at 2 h (superacute) or 24 h (acute) after MCAO. Behavioral tests showed significant improvement of neurological deficits in the HGF-transferred MSCs (MSC-HGF)-treated group compared with the phosphate-buffered saline (PBS)-treated and MSCs-only-treated group. The significant difference of infarction areas on day 3 was detected only between the MSC-HGF group and the PBS group with the superacute treatment, but was detected among each group on day 14 with both transplantations. After the superacute transplantation, we detected abundant expression of HGF protein in the ischemic brain of the MSC-HGF group compared with others on day 1 after treatment, and it was maintained for at least 2 weeks. Furthermore, we determined that the increased expression of HGF was derived from the transferred HGF gene in gene-modified MSCs. The percentage of apoptosis-positive cells in the ischemic boundary zone (IBZ) was significantly decreased, while that of remaining neurons in the cortex of the IBZ was significantly increased in the MSC-HGF group compared with others. The present study shows that combined therapy is more therapeutically efficient than MSC cell therapy alone, and it may extend the therapeutic time window from superacute to acute phase.