Peripheral-Nerve and Spinal-Cord Regeneration in Mice Using Hair-Follicle-Associated Pluripotent (HAP) Stem Cells

The Potential of Hair-Follicle-Associated Pluripotent (HAP) Stem Cells for Regenerative Medicine

Nestin-expressing hair-follicle-associated pluripotent (HAP) stem cells from mouse and human have been shown to differentiate into neurons, glia, keratinocytes, smooth muscle cells, cardiac muscle cells, and melanocytes in vitro. HAP stem cells have promoted the recovery of peripheral nerve and spinal cord injuries in mouse models by differentiating into glial fibrillary acidic protein (GFAP)-positive Schwann cells. HAP stem cells enclosed on polyvinylidene fluoride membranes (PFM) were transplanted into the severed thoracic spinal cord of nude mice. After implantation, HAP stem cells differentiated into neurons and glial cells, which effected complete reattachment of the thoracic spinal cord.HAP stem cells were implanted into the injured brain of C57BL/6J or nude mice with induced intracerebral hemorrhage (ICH). After implantation, HAP stem cells differentiated into neurons, astrocytes, oligodendrocytes, and microglia in the ICH site, and demonstrated a significant functional improvement in mice. HAP-cell-sheets implanted on wounds in diabetic db/db mice effected wound healing. The levels of inflammation in the wound was suppressed by HAP-cell-sheet implantation. These results suggest autologous HAP stem cells can be used to heal refractory diabetic ulcers. HAP stem cells can differentiate into mature beating atrial and ventricular cardiomyocytes when cultured with specific supplements and have the potential for heart regeneration. HAP stem cells are readily obtained from scalp hair follicles, they do not develop teratomas and do not lose differentiation ability when cryopreserved. These results suggest that HAP stem cells have the potential as be a better source for regenerative medicine compared to induced pluripotent stem cells (iPS) or embryonic stem (ES) cells.

Peripheral Nerve Regeneration Using Different Germ Layer-Derived Adult Stem Cells in the Past Decade

Peripheral nerve injuries (PNIs) are some of the most common types of traumatic lesions affecting the nervous system. Although the peripheral nervous system has a higher regenerative ability than the central nervous system, delayed treatment is associated with disturbances in both distal sensory and functional abilities. Over the past decades, adult stem cell-based therapies for peripheral nerve injuries have drawn attention from researchers. This is because various stem cells can promote regeneration after peripheral nerve injuries by differentiating into neural-line cells, secreting various neurotrophic factors, and regulating the activity of in situ Schwann cells (SCs). This article reviewed research from the past 10 years on the role of stem cells in the repair of PNIs. We concluded that adult stem cell-based therapies promote the regeneration of PNI in various ways.

Hair-Follicle-Associated Pluripotent (HAP) Stem Cells Can Extensively Differentiate to Tyrosine-Hydroxylase-Expressing Dopamine-Secreting Neurons

Hair-follicle-associated pluripotent (HAP) stem cells are located in the bulge area of hair follicles from mice and humans and have been shown to differentiate to neurons, glia, keratinocytes, smooth muscle cells, melanocytes and beating cardiac muscle cells in vitro. Subsequently, we demonstrated that HAP stem cells could effect nerve and spinal-cord regeneration in mouse models, differentiating to Schwann cells and neurons in this process. HAP stem cells can be banked by cryopreservation and preserve their ability to differentiate. In the present study, we demonstrated that mouse HAP stem cells cultured in neural-induction medium can extensively differentiate to dopaminergic neurons, which express tyrosine hydroxylase and secrete dopamine. These results indicate that the dopaminergic neurons differentiated from HAP stem cells may be useful in the future to improve the symptoms of Parkinson's disease in the clinic.

Stem-cell-based therapies to enhance peripheral nerve regeneration

Peripheral nerve injury remains a major cause of morbidity in trauma patients. Despite advances in microsurgical techniques and improved understanding of nerve regeneration, obtaining satisfactory outcomes after peripheral nerve injury remains a difficult clinical problem. There is a growing body of evidence in preclinical animal studies demonstrating the supportive role of stem cells in peripheral nerve regeneration after injury. The characteristics of both mesoderm-derived and ectoderm-derived stem cell types and their role in peripheral nerve regeneration are discussed, specifically focusing on the presentation of both foundational laboratory studies and translational applications. The current state of clinical translation is presented, with an emphasis on both ethical considerations of using stems cells in humans and current governmental regulatory policies. Current advancements in cell-based therapies represent a promising future with regard to supporting nerve regeneration and achieving significant functional recovery after debilitating nerve injuries.

Aldefluor protocol to sort keratinocytes stem cells from skin

PURPOSE

To investigate the use Aldefluor® and N, N - Dimethylaminobenzaldehyde (DEAB) to design a protocol to sort keratinocyte stem cells from cultured keratinocytes from burned patients.

METHODS

Activated Aldefluor® aliquots were prepared and maintained at temperature between 2 to 8°C, or stored at -20°C. Next, the cells were collected following the standard protocol of sample preparation.

RESULTS

Best results were obtained with Aldefluor® 1.5µl and DEAB 15 µl for 1 x 106 cells, incubated at 37°C for 15 minutes. Flow cytometer range for keratinocyte stem cells separation was evaluated. There were 14.8% of stem cells separated in one sample of keratinocyte culture used to pattern the protocol. After being defined the ideal concentration, the same test pattern was performed in other keratinocyte samples. We observed a final mean of 10.8%.

CONCLUSION

Aldefluor® has been shown as a favorable marking of epidermal keratinocyte stem cells for subsequent separation on a flow cytometer, with detection of 10.8% of epidermal keratinocyte stem cells, in this protocol.