Dai-Jung Chung

Intraarterially delivered human umbilical cord blood‐derived mesenchymal stem cells in canine cerebral ischemia

The present study examined the effects of human umbilical cord blood‐derived mesenchymal stem cells (HUCB‐derived MSCs) delivered through the basilar artery in a canine thromboembolic brain ischemia model. Cerebral ischemia was induced through occlusion of the middle cerebral artery by injecting thrombus emboli into 10 beagles. In the HUCBC group (n = 5), 1 × 106 HUCB‐derived MSCs were transplanted through the basilar artery 1 day after ischemic induction using an endovascular interventional approach. In the control group (n = 5), phosphate‐buffered saline (PBS) was injected in the same manner in as the HUCBC group. Upon neurobehavioral examination, earlier recovery was observed in the HUCBC group. The HUCBC group showed a decrease in the infarction volume at 1 week after cerebral ischemic induction, whereas the control group showed an increase in the infarction volume at 1 week, by magnetic resonance image analysis. Transplanted cells had differentiated into neurons and astrocytes and were observed in and around endothelial cells that were positive for von Willebrand factor (vWF). HUCB‐derived MSCs expressed neuroprotective factors, such as brain‐derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF), at 4 weeks after the transplantation. The transplanted cells demonstrated their efficacy by reducing the infarction lesion volume and through earlier recovery from the neurological deficit. These results suggest that intraarterial transplantation of HUCB‐derived MSCs could be useful in clinical treatment of cerebral ischemia.

Schwann cell-like remyelination following transplantation of human umbilical cord blood (hUCB)-derived mesenchymal stem cells in dogs with acute spinal cord injury

Human umbilical cord blood derived mesenchymal stem cells (hUCB-MSCs) have significant therapeutic potential in cell-based therapies following spinal cord injury (SCI). To evaluate this potential, we conducted our preliminary investigations on the remyelination of injured spinal cords with hUCB-MSC transplantations and we observed its long term effects on dogs with SCI. Of the ten injured dogs, seven were transplanted with hUCB-MSCs 1 week after SCI, whereas the remaining three dogs were not transplanted. Two transplanted dogs died over the first month after transplantation because of urinary tract infection, bedsores and sepsis. The SCI dogs showed no improvement in motor and sensory functions and their urinary dysfunction persisted until they were euthanized (from 3 months to 1 year) while hind-limb recovery in 4 dogs among the five transplanted dogs was significantly improved. In the recovered dogs, functional recovery was sustained for three years following transplantation. Histological results from five transplanted dogs showed that many axons were remyelinated by P0-positive myelin sheaths after transplantation. Our results suggest that transplantation of hUCB-derived MSCs may have beneficial therapeutic effects. Furthermore, histological results provided the first in vivo evidence that hUCB-MSCs are able to enhance the remyelination of peripheral-type myelin sheaths following SCI.

Percutaneous transplantation of human umbilical cord blood–derived multipotent stem cells in a canine model of spinal cord injury

OBJECT The authors describe a method for percutaneous transplantation of human umbilical cord blood (hUCB)-derived multipotent stem cells (MSCs) under fluoroscopic guidance. The investigators then tested whether percutaneous transplantation of hUCB-derived MSCs improved neurological functional recovery after acute spinal cord injury (SCI). METHODS The authors induced SCI in 10 dogs by percutaneous balloon compression. The 10 injured dogs were assigned randomly to the following groups (2 dogs each): Group 1, evaluated 2 weeks after sham transplantation; Group 2, evaluated 2 weeks after transplantation; Group 3, evaluated 4 weeks after sham transplantation; Group 4, evaluated 4 weeks after transplantation; and Group 5, evaluated 4 weeks after multispot transplantations. The dogs with sham transplantation (Groups 1 and 3) received the same volume of saline, as a control. A spinal needle was advanced into the spinal canal, and the investigators confirmed that the end of the spinal needle was located in the ventral part of spinal cord parenchyma by using contrast medium under fluoroscopic guidance. The hUCB-derived MSCs were transplanted into the cranial end of the injured segment in 6 injured dogs at 7 days after SCI. RESULTS Two dogs in Group 2 showed no improvement until 2 weeks after transplantation. Three of 4 dogs (Groups 4 and 5) that received cellular transplants exhibited gradual improvement in hindlimb locomotion from 3 weeks after cell transplantation. The CM-DiI-labeled hUCB-derived MSCs were observed in the spinal cord lesions at 4 weeks posttransplantation and exerted a significant beneficial effect by reducing cyst and injury size. The transplanted cells were positive for NeuN, glial fibrillary acidic protein, and von Willebrand factor. CONCLUSIONS The percutaneous transplantation technique described here can be easily performed, and it differs from previous techniques by avoiding surgical exposure and allowing cells to be more precisely transplanted into the spinal cord. This technique has many potential applications in the treatment of human SCI by cell transplantation. The results also suggest that transplantation of hUCB-derived MSCs may have therapeutic effects that decrease cavitation for acute SCI.

Development of an improved canine model of percutaneous spinal cord compression injury by balloon catheter

We developed a minimally invasive canine model of spinal cord injury (SCI). A balloon catheter was inserted into the epidural space via the lumbosacral space, and inflated between L2 and L3 for 30 or 60 min under fluoroscopic guidance. Motor function after SCI was assessed using modified Tarlov scale. All seven dogs showed complete paraplegia after the procedure, neurological problems were evident and the modified Tarlov scores remained at zero after the SCI procedure; no improvement in clinical signs was observed. The dogs underwent 3T MR imaging at 3 days and 1 year after SCI. Histopathologic examinations were conducted at 2 weeks, 12 weeks and 1 year after SCI. In the present study, we described an animal model of minimally invasive spinal cord injury using a balloon catheter without laminectomy under fluoroscopic guidance. And, this percutaneous spinal cord compression injury model has many potential applications. The described percutaneous spinal cord compression injury model offers a new means of administering SCI and has many potential applications.

Percutaneous transplantation of human umbilical cord-derived mesenchymal stem cells in a dog suspected to have fibrocartilaginous embolic myelopathy

The use of human umbilical cord blood-derived mesenchymal stem cells for cell transplantation therapy holds great promise for repairing spinal cord injury. Here we report the first clinical trial transplantation of human umbilical cord (hUCB)-derived mesenchymal stem cells (MSCs) into the spinal cord of a dog suspected to have fibrocartilaginous embolic myelopathy (FCEM) and that experienced a loss of deep pain sensation. Locomotor functions improved following transplantation in a dog. Based on our findings, we suggest that transplantation of hUCB-derived MSCs will have beneficial therapeutic effects on FCEM patients lacking deep pain sensation.

Expression of Neurotrophic Factors in Injured Spinal Cord after Transplantation of human-Umbilical Cord Blood Stem Cells in Rats

We induced percutaneous spinal cord injuries (SCI) using a balloon catheter in 45 rats and transplanted human umbilical cord blood derived mesenchymal stem cells (hUCB-MSCs) at the injury site. Locomotor function was significantly improved in hUCB-MSCs transplanted groups. Quantitative ELISA of extract from entire injured spinal cord showed increased expression of brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF) and neurotrophin-3 (NT-3). Our results show that treatment of SCI with hUCB-MSCs can improve locomotor functions, and suggest that increased levels of BDNF, NGF and NT-3 in the injured spinal cord were the main therapeutic effect.

An Etiologic Study of Rabbit Dermatitis at Large Rabbit Farms in South Korea

This study was carried out between August and September 2007 to determine the causative agents and epidemiologic features of rabbit dermatitis in Korea. Rabbits were shipped to the laboratory in the College of Veterinary Medicine from 10 rabbit farms. A total of 520 hair, blood, and skin specimens collected from skin lesions of 40 rabbits with suspected dermatopathy were examined mycologically, bacteriologically, and parasitologically. The positive rates of dermatophytosis, bacterial skin dermatitis, and ectoparasite dermatitis were 95, 92.5, and 7.5%, respectively. The etiologic agents of dermatophytosis were identified as Trichophyton mentagrophyte (95%), non-dermatophytic filamentous fungi such as Aspergillus spp. (5%), and Cryptococcus humilocus (2.5%). With respect to bacteria-related skin dermatitis, Staphylococcus coagulase negative was the most common etiological agent. Staphylococcus aureus was the second most frequent causative agent. Most of the pathogenic isolates were resistant to tetracycline, and aminoglycosides such as amikacin and gentamicin were the most effective drugs against the pathologic bacteria isolated. Ectoparasites were rarely detected in this study. Only Psoroptes cuniculis was detected in 3 (7.5%) out of the 40 tested rabbits. The role of ectoparasites as a causative agent of dermatitis in rabbits in this study was minimal. Our results provide important information related to rabbit dermatitis treatments and researches.

Effects of Single Total Body Irradiation (TBI) on the Peripheral Blood of Piglets

We examined total body irradiation (TBI)-induced effects by complete blood count (CBC) and fluorescence-activated cell sorter analysis (FACS) in the piglet following radiation irritation. A CBC included red blood cell count, white blood cell count, and platelet cell count. Four piglets were examined in this study and each piglet was divided by irradiation dose, two piglets with 4 Gy, two with 6 Gy, one with 8 Gy. All piglets showed leukopenia, thrombocytopenia after irradiation. In 6 and 8 Gy group, three piglets showed severe hemostatic disorder and gastrointestinal disorder suchas diarrhea and anorexia, and they died between 10 and 15 days after radiation irritation. In 4 Gy, two piglets showed no clinical sign after radiation injury, but persistent leukopenia was shown in blood examination. We suggest that a single TBI dose less than 6 Gy is adequate for conditioning piglet for bone marrow transplantation.