Jung Youn Jo

Safety of Intravenous Infusion of Human Adipose Tissue-Derived Mesenchymal Stem Cells in Animals and Humans

Adipose tissue-derived mesenchymal stem cells (AdMSCs) represent an attractive and ethical cell source for stem cell therapy. With the recent demonstration of MSC homing properties, intravenous applications of MSCs to cell-damaged diseases have increased. In the present study, the toxicity and tumorigenicity of human AdMSCs (hAdMSCs) were investigated for clinical application. Culture-expanded hAdMSCs showed the typical appearance, immunophenotype, and differentiation capacity of MSCs, and were genetically stable at least 12 passages in culture. Cells suspended in physiological saline maintained their MSC properties in a cold storage condition for at least 3 days. To test the toxicity of hAdMSCs, different doses of hAdMSCs were injected intravenously into immunodeficient mice, and the mice were observed for 13 weeks. Even at the highest cell dose (2.5×10(8) cells/kg body weight), the SCID mice were viable and had no side effects. A tumorigenicity test was performed in Balb/c-nu nude mice for 26 weeks. Even at the highest cell dose (2×10(8) MSCs/kg), no evidence of tumor development was found. In a human clinical trial, 8 male patients who had suffered a spinal cord injury >12 months previous were intravenously administered autologous hAdMSCs (4×10(8) cells) one time. None of the patients developed any serious adverse events related to hAdMSC transplantation during the 3-month follow-up. In conclusion, the systemic transplantation of hAdMSCs appears to be safe and does not induce tumor development.

Journey of Mesenchymal Stem Cells for Homing: Strategies to Enhance Efficacy and Safety of Stem Cell Therapy

Human mesenchymal stem cells (MSCs) communicate with other cells in the human body and appear to “home” to areas of injury in response to signals of cellular damage, known as homing signals. This review of the state of current research on homing of MSCs suggests that favorable cellular conditions and the in vivo environment facilitate and are required for the migration of MSCs to the site of insult or injury in vivo. We review the current understanding of MSC migration and discuss strategies for enhancing both the environmental and cellular conditions that give rise to effective homing of MSCs. This may allow MSCs to quickly find and migrate to injured tissues, where they may best exert clinical benefits resulting from improved homing and the presence of increased numbers of MSCs.

Recloned dogs derived from adipose stem cells of a transgenic cloned beagle

A number of studies have postulated that efficiency in mammalian cloning is inversely correlated with donor cell differentiation status and may be increased by using undifferentiated cells as nuclear donors. Here, we attempted the recloning of dogs by nuclear transfer of canine adipose tissue-derived mesenchymal stem cells (cAd-MSCs) from a transgenic cloned beagle to determine if cAd-MSCs can be a suitable donor cell type. In order to isolate cAd-MSCs, adipose tissues were collected from a transgenic cloned beagle produced by somatic cell nuclear transfer (SCNT) of canine fetal fibroblasts modified genetically with a red fluorescent protein (RFP) gene. The cAd-MSCs expressed the RFP gene and cell-surface marker characteristics of MSCs including CD29, CD44 and thy1.1. Furthermore, cAd-MSCs underwent osteogenic, adipogenic, myogenic, neurogenic and chondrogenic differentiation when exposed to specific differentiation-inducing conditions. In order to investigate the developmental potential of cAd-MSCs, we carried out SCNT. Fused-couplets (82/109, 75.2%) were chemically activated and transferred into the uterine tube of five naturally estrus-synchronized surrogates. One of them (20%) maintained pregnancy and subsequently gave birth to two healthy cloned pups. The present study demonstrated for the first time the successful production of cloned beagles by nuclear transfer of cAd-MSCs. Another important outcome of the present study is the successful recloning of RFP-expressing transgenic cloned beagle pups by nuclear transfer of cells derived from a transgenic cloned beagle. In conclusion, the present study demonstrates that adipose stem cells can be a good nuclear donor source for dog cloning.