Biomedical subjects

Hee-Kwon Park

Publications and source records attributed to Hee-Kwon Park.

3 recordsLinked to original sources

PubMed2005

Granulocyte colony-stimulating factor induces sensorimotor recovery in intracerebral hemorrhage.

Granulocyte colony-stimulating factor (G-CSF) has been used in the treatment of neutropenia in hematologic disorders. The neuroprotective and anti-inflammatory effects of G-CSF were reported in various neurological disease models. In this study, we examined whether G-CSF induces functional recovery after intracerebral hemorrhage (ICH). ICH was induced using collagenase injection in adult rats. Either G-CSF (50 microg/kg, i.p.) or saline was given from 2 h after ICH and every 24 h for 3 days. 72 h after ICH induction, the rats were sacrificed for histological analysis and measurement of brain edema. Behavioral tests were performed before and 1, 7, 14, 21, 28, and 35 days after ICH. We also measured the blood-brain barrier (BBB) permeability using Evans blue dye injection method. G-CSF-treated rats recovered better on rotarod and limb placing tests, starting from 14 days throughout 5 weeks after ICH. The brain water content and BBB permeability of G-CSF-treated group decreased in the lesioned hemispheres compared with those of ICH-only group. In G-CSF-treated group, the number of TUNEL+, myeloperoxidase+, and OX42+ cells was smaller than that of ICH-only group in the periphery of hematoma. These findings suggest that G-CSF induces long-term sensorimotor recovery after ICH with reduction of brain edema, inflammation, and perihematomal cell death.

Animals↗

PubMed2004

Human neural stem cells improve sensorimotor deficits in the adult rat brain with experimental focal ischemia.

Ischemic stroke is caused by the interruption of cerebral blood flow that leads to brain damage with long-term sensorimotor deficits. Stem cell transplantation may recover functional deficit by replacing damaged brain. In this study, we attempted to test whether the human neural stem cells (NSCs) can improve the outcome in the rat brain with intravenous injection and also determine the migration, differentiation and the long-term viabilities of human NSCs in the rat brain. Focal cerebral ischemia was induced by intraluminal thread occlusion of middle cerebral artery (MCA). One day after surgery, the rats were randomly divided into two groups: NSCs-ischemia vs. Ischemia-only. Human NSCs infected with retroviral vector encoding beta galactosidase were intravenously injected in NSCs-ischemia group (5 x 10(6) cells) and the same amount of saline was injected in Ischemia-only group for control. The animals were evaluated for 4 weeks using turning in an alley (TIA) test, modified limb placing test (MLPT) and rotarod test. Transplanted cells were detected by X gal cytohistochemistry or beta gal immunohistochemistry with double labeling of other cell markers. The NSCs-ischemia group showed better performance on TIA test at 2 weeks, and MLPT and rotarod test from 3 weeks after ischemia compared with the Ischemia-only group. Human NSCs were detected in the lesion side and labeled with marker for neurons or astrocytes. Postischemic hemispheric atrophy was noted but reduced in NSCs-ischemia group. X gal+ cells were detected in the rat brain as long as 540 days after transplantation. Our data suggest intravenously transplanted human NSCs can migrate and differentiate in the rat brain with focal ischemia and improve functional recovery.

Animals↗

PubMed2003

Cerebral cavernous malformations with dynamic and progressive course: correlation study with vascular endothelial growth factor.

BACKGROUND: Cerebral cavernous malformations (CCMs) are reported to exhibit a wide range of dynamic patterns including growth, regression, and de novo formation, which generally show slow and steady courses. Although the pathogenesis of CCMs is not well known, vascular endothelial growth factor (VEGF) has been suggested as a possible mediating factor. OBJECTIVES: To report CCMs showing rapid progression over a short period and to investigate these biological characteristics. DESIGN: Experimental study. SETTING: Tertiary referral center, neurology department. Patient A 40-year-old man was admitted because of a left-sided numbness, vertigo, and ataxia, which were attributed to a pontine hemorrhage. He had experienced a left-sided weakness 6 months before admission, and thereafter had complained of intermittent headache. Serial brain magnetic resonance images showed multiple intracerebral microhemorrhages throughout the cerebral hemispheres. A biopsy of the lesion confirmed the diagnosis of CCM. MAIN OUTCOME MEASURES: We investigated the expression of VEGF by immunohistochemistry of the biopsy specimen. Dynamic patterns of CCMs, obtained with spin-echo magnetic resonance images with gradient-echo sequences, were compared with serial serum VEGF concentrations, determined by enzyme-linked immunosorbent assay. RESULTS: Immunohistochemistry of the specimen displayed increased VEGF expression. Serial magnetic resonance images during 7 months showed dynamic signal changes of the preexisting lesions and 15 de novo formations in many cortices. The VEGF level in serum increased during this dynamic period and became normal during the steady and resolving stages. CONCLUSIONS: Cerebral cavernous malformations can be progressively deteriorating. The endothelial proliferation induced by VEGF is likely to be an important aspect of the pathogenetic mechanisms of CCMs.

Adult↗