Specific enhancement of vascular endothelial growth factor (VEGF) production in ischemic region by alprostadil--potential therapeutic application in pharmaceutical regenerative medicine.

Alprostadil (lipo-PGE1) is a drug delivery system preparation. This preparation is applied to treat refractory skin ulcers and arteriosclerosis obliterans. We investigated the effects of alprostadil by using the earflap ischemic model. The following results were obtained: 1) Treatment with alprostadil significantly increased the VEGF contents in an ischemic ear; 2) Treatment with alprostadil resulted in strongly expressed VEGF levels only in the ischemic region; 3) Image analysis revealed a significant increase in the number of vessel bypasses and paths after flap creation with alprostadil administration compared to the vehicle-treated ears. The results suggest that it may be possible to apply alprostadil as one device for regenerative medical technology.

Improvement of hind-limb paralysis following traumatic spinal cord injury in rats by grafting normal human keratinocytes: new cell-therapy strategy for nerve regeneration.

Somatic (adult) stem cells are thought to have pluripotency, just as do embryotic stem (ES) cells. We investigated the possibility that grafted epithelial keratinocytes could induce spinal cord regeneration in an animal model of spinal cord injury (SCI). Normal human keratinocytes were cultured by the routine technique, and normal human dermal fibroblasts were cultured by a similar method as a control group. SCI model was prepared by dropping a 10-g weight onto the exposed spinal cord of rats from a height of 25 mm, and 8 days later, the cultured cells were grafted into the injury site. Motor function was significantly improved in the cultured-keratinocyte-grafted group compared with that in the fibroblast-grafted group. After functional observation, human nestin- and nuclei-positive cells were found at the grafted spinal cord. Grafted cultured keratinocytes induced in vitro morphological changes in the neural induction medium. These results indicated one possibility that some of the grafted cultured keratinocytes survived and could have contributed to neural regeneration. On the other hand, it should be noted that the grafted cultured keratinocytes secreted a large amount of enzymes and/or growth factors. Therefore, another possibility is that the grafted-keratinocyte-derived factors could induce survived cell growth and endogenous neural differentiation of spinal-nerve-derived stem cells surrounding the injured spinal cord, leading to functional recovery. Epithelial stem cell therapy may be applied clinically in the near future to treat SCI.