The Experimental Study Of Treatment To Sensorineural Deafness With Human Adipose-derived Mesenchymal Stem Cells

The inner ear hair cells are essential for hearing and balance.When hair cells are lost through trauma,toxicity,infection,genetic disorders,or aging,that can lead to impaired hearing or disruption of vestibular reflexes.Cochlear hair cells are a terminally differentiated cell population that is crucial for hearing and have no possibility of spontaneous regeneration in mammals.Hearing impairment in humans is,in most cases, a direct consequence of hair-cell loss.Cochlear implants to restore some hearing after neurosensory hearing loss(NSHL) are,at present,the only therapy for these people.In contrast to this therapy,replacement of hair cells via stem cell therapies holds the promise for a cure.Stem cells are characterized as undifferentiated,toti-,pluri-or multipotent,and self-renewing cells that have the capacity to differentiate into any cell type of the body given appropriate intracellular gene regulation,intercellular communication,and environmental cues.Adipose-derived mesenchymal stem cells (ADMSCs) can be induced to exhibit several phenotypic,morphologic,and excitory characteristics consistent with developing neuronal and glial tissue.We therefore asked whether ADMSCs could generate cochlear sensory hair cells.The aim of our study is to induce human adipose-derived mesenchymal stem cells(hAD-MSCs) to differentiate to generate cochlear sensory hair cells,and to find a possible source of stem cells for cell therapy for NSHL.We further delivered hAD-MSCs into the cochlea of deafened mice and examined the survival,migration and location of transplanted cells within the cochlear.Objective 1.To explore the feasibility of directionally inducing human adipose-derived mesenchymal stem cells(hAD-MSCs) in vitro towards cochlear sensory hair cells.2.To examine the survival,migration,and differentiation of transplanted hADMSCs within the cochlear of drug deafened mice.Methods1.Mesenchymal stem cells from human adipose tissue were isolated,purified and cultured in vitro.2.HADMSCs were induced to neural progenitor-like cell by using special cultivate system with some cell factors,which were tested by immunofluorescence.3.The processed hADMSCs co-cultured with embryonic chick otic vesicle cells,were converted it into cochlear sensory hair cells.The characteristic marks of cochlear sensory hair cells were detected by immnofluoresence method.4.The combination of kanamycin sulfate and frusemide was used to build drug deafened mice model.5.HADMSCs were transplanted into cochlear of deafened mice through lateral semicircular canal,and were examined by immnofluoresence and reverse transcription polymerase chain reaction(RT-PCR).Results1.Morphologically,hAD-MSCs were induced to differentiate into neural progenitor cells and expressed specific neural marker.2.After being co-cultured with embryonic chick otic vesicle cells,hAD-MSCs expressed specific surface markers of cochlear inner ear hair cells,such as the transcription factors Math1(murine atonal homologue 1) and myosin VIIa.3.Small numbers of hADMSCs were capable of survival in the deafened mammalian cochlea for up to 2 weeks,without causing an inflammatory tissue response.A proportion of these cells was detected in the Rosenthal's canal and cochlear sensory epithelium,evidenced by immunofluorescence detection of expression of MyosinVIIa. RT-PCR found that beta-actin and Math1 express of the experimental group was higher than that of the control group.Conclusion 1.HADMSCs can be directionally induced to differentiate towards hair cell-like cells in vitro given appropriate regulation and environmental cues.2.HADMSCs can survive for at least 2 weeks after transplanted into mice cochlear, and migrate into the Rosenthal's canal and cochlear sensory epithelium with expression of characteristic marks of cochlear sensory hair cells.3.Through the lateral semicircular canal,hAD-MSCs can be transplanted into cochlear safely and effectively.