The Function Of Endothelial Progenitor Cells Of Patients With Presbycusis

Background and Purpose:Hearing loss has a huge impact on the affected individual as well as on society. It is estimated that 278 million persons worldwide (two-thirds of whom reside in developing countries) suffer from disabling hearing loss.Not only is one baby out of 1000 born with hearing loss, but more than 50%of over-65s suffer from hearing loss. Hearing loss of adult onset is one of the ten leading causes of disability-adjusted life years globally. The impact of hearing loss on health care costs will very probably increase in the future. Our country is developing country, and with the society developing, the population of aging is creasing. Presbycusis is defined as a common type of hearing loss caused by cochlear degeneration which affects mainly the base of the cochlea, impairing hearing in the higher frequencies. One of the causes of presbycusis is related with the aging of arteries in cochlear. The aging of arteries in cochlear of presbycusis might be related with the insufficient capacity of repairing and regeneration. Endothelial progenitor cells(EPCs), showed endothelial cell feature, and play an important role in the process of reparation of blood vessels and re-endothelialization during the neovascularization of ischemic organs. Researches had indicated that many factors could affect the number and capacity of EPCs in peripheral blood. Aging, smoking, absent exercise, hypertension, ischemic celebral disease,1 and 2 type diabetes and so on, these diseases would decrease the number and function. What will happen for EPCs in patients with presbycusis? So we aimed to investigate the function of EPCs of patients with presbycusis and explore the underlying mechanism.Methods1.Study Subjects:Sixteen patients with presbycusis was included in our research. 7 females,9 men, and their ages were from 60 years to 69 years, mean 64.7 years. They had median hearing loss and with presbycusis history from 9 months to 2 years and 3 months, exclude the history of diseases and drugs treatment that may be affect EPCs. Seven females and 9 men health aging from 60 to 68 years (mean 65.5years) were enrolled.2. Isolation, cultivation and Characterization of EPCs:Peripheral blood(10 ml) was drawn by venipuncture, Mononuclear cells were isolated by density gradient method using Ficoll-Paque Plus. Cells were cultured with M199 medium, which contains 20% fetal-calf. At day 7, EPCs were incubated with Dil-acLDL and FITC-UEA-I, Samples were examined with laser scanning confocal microscope. Only cells exhibiting double fluorescence were identified as EPCs.3. Numbers, Adhesion, Proliferation, Migration of EPCs colonies and EPCs: The numbers of EPCs and EPCs colonies were determined by counting 5 random high-power (X 200) microscope fields per subject at day 7. After the numbers of EPC and EPC colony were counted, cells were assayed or harvested for further study.1×105cells/ml EPCs of every group were replanted onto fibronectin-coated culture dishes and incubated at 37℃for 30 minutes. Adherent cells were counted 5 random high-power (×200) microscope fields per subject.2×103 cell/ml EPCs of every group were replanted 96-well culture dishes, MTT Cell Proliferation and Cytotoxicity Assay Kit were applied to assay proliferation of EPCs. The OD value was measured at 570nm.2×104 cells/ml EPCs of every group resuspended in 50ul M199 medium were placed in the upper chamber of a modified Boyden chamber. 25ul M199 and human recombinant VEGF (50ng/ml) were placed in the lower compartment of the chamber. After 24h incubation at 37℃, cells migrating into the lower chamber were counted. Results1.Number assay of EPCs colonies and EPCs, adhesion, migration and proliferation of EPCs:Compared with control group, the number of EPCs(54.32±9.24 versus 67.64±8.39) and EPCs colonies(1.40±0.37 versus 2.88±0.48), adhesive(17.32±5.18 versus 22.58±5.46), proliferative (0.154±0.042 versus 0.226±0.574), migrating faculty(11.18±2.73 versus 15.72±3.43)and migrating of EPCs in presbycusis group significantly decreased (P<0.05).Conclusions The number of EPCs and EPCs colonies, adhesive, migrating and proliferative faculty of EPCs in patients with presbycusis significantly increased. This may be one of mechanisms of presbycusis.