Exploration Of Human Nail Precursor Cells(Stem Cells)and Studies On Its Activity

Part? Identification and Localization of Human Nail Precursor Cells(Stem Cells)Objective:Fingertip defects and amputations are common injuries of the upper extremities,which causing great pain to the patients.After treatment of these patients,a considerable number of the population will still suffer from finger or nail deformities,which may be accompanied by a series of disability and cosmetology related problems.At present,treatment schemes for fingertip defects have their limitations.Most reconstructed fingertip cannot form its unique original features,and it is accompanied by the destruction of normal tissues.We hope to be able to induce fingertip regeneration by tissue autoregeneration.The regulation of adult stem cells is the basis of organ maintenance and tissue regeneration.Of the four accessory organs of the skin,three other accessory organs besides nails,hair follicles,sweat glands and sebaceous glands,the existence of stem cells has been demonstrated.So we hypothesized that there would also be stem cells of nails,markers that express part of the epidermal stem cells,that have stem cell properties and contribute to the regeneration of the nail and its surrounding structures.Methods: We used vitro specimens of children with congenital polydactyly and adults who had their fingers amputated by trauma from our hospital.The guardian or patient should donate the severed finger with written informed consent.Immunofluorescence staining and immunohistochemical staining were used to detect the expression of related markers Keratin 15(K15),Keratin 14(K14),Keratin 19(K19),CD29,CD34 and Lgr6 in human specimens.Results: We detected the expression of the stem cell marker(K15)in cells from the tissues surrounding the nail,which are located near the NPF(Nail Proximal Fold)and nail matrix above the deck.The expression of the markers of K14,K15,K19,CD29,CD34 and Lgr6 in proximal fold cells and proximal nail stromal cells of all specimens was detected by immunohistochemical staining.Moreover,through co-immunofluorescence staining of K14 and K15,we found that the expression of K14,K15,K19,CD29,CD34 and Lgr6 in human fingernails was the same cell population.Conclusions: Nail progenitor cells(stem cells)exist in the tissues surrounding the human nail and are highly expressed in K14,K15,K19,CD29,CD34 and Lgr6.Part? Relationship between the Number and Activity of Human Nail Precursor Cells(Stem Cells)and AgeObjective:Function of stem cells is known to decline with age,a process that may be linked to loss of maintenance of tissue homeostasis leading to organ failure and age-related diseases.Age-related changes in the external environment,their own systemic or local tissue environment,coupled with internal changes in the cell itself,and repeated use,are the underlying causes of potential stem cell dysfunction leading to organ or body failure.Aging is associated with reduced tissue regeneration,leading to an increase in degenerative diseases and cancers.The full cloning of hair follicle stem cells in the elderly can be passed,but the signs of self-renewal abate in later generations.These previous studies have provided us with ideas.In this section,we investigate how human nail precursor cells change with age and what age-related characteristics they exhibit.Methods: We used vitro specimens of children with congenital polydactyly and adults who had their fingers amputated by trauma from our hospital.The guardian or patient shall donate the severed finger with written informed consent.By immunofluorescence staining,immunohistochemical staining,CCK-8,fluid cytology and other experimental methods,select the cells of the young group(0 to 3 years old)and elderly group(60-70 years)to compare,and through the isolation and culture of people nails precursor cells and clone formation test,etc.,which in many ways,multi-angle,preliminary discussion on the quantity of nails precursor cells,and active relationship with the age.Results: We detected that:(1)a variety of stem cell markers(K14,K15,K19,CD29,CD34 and Lgr6)were expressed in nail precursor cells of different ages,and the relative amount was independent of the increase in age.(2)the absolute number of these cells increased with age: through H&E staining and immunofluorescence staining,we found that the absolute number of cells,including nail precursor cells and other cells in the epidermis,increased with age;(3)the fluorescence intensity of precursor cells in aging nails is weaker than that of young nails.These results suggest functional differences between young and old nail precursor cells;(4)in all aged nail samples,the proliferation of nail roots decreased;(5)cloning ability of nail precursor cells is weaker than that of young people.Conclusions: The absolute number of human nail progenitor cells(stem cells)increased with age,and the proliferation and cloning ability of nail progenitor cells were weaker in the elderly than those in the young.Part? Study on the Relationship between the Human Nails Growth Rate and AgeObjective:Nails and hair growth have much in common,scientists explore why hair growth will decline with age,especially less hair and eventually falls off.Hair follicle stem cells gradually enter a dormant state during the aging process,and the resting time of hair follicles will be prolonged with the aging of animals,while the hair density of humans will decline with the aging.We speculate whether the growth rate of nails is also related to the status of nail stem cells.In this part of our study,we measured the growth rate of fingernails in different age groups(children and the elderly)to estimate the average growth rate of fingernails in healthy people of different ages,and thus proved once again that the nail precursor cells we found in human fingernails may be nail stem cells.Methods: We openly recruited 72 healthy natural persons to participate in this part of the study,including children aged 0-3 years and elderly people aged 60-70 years.The guardian or patient should sign informed consent.A nail file was used to mark the distal base of the crescent of each finger nail of the participant's hands in a moderate depth to ensure that the mark was still visible 4 weeks later.Participants returned to the hospital at weekends 4,8 and 12.During the follow-up visit,three uniformly trained staff members measured the distance of the nail mark from the baseline of the distal crescent of the nail.Results: We found that the growth rate of the thumbnail was significantly higher than that of the other fingers,while the growth rate of the little finger was the slowest.The average growth rate of children's thumbnails was 4.70mm/month,while that of the elderly was 3.51mm/month.The average growth rate of children's little finger nails was 2.96mm/month,while that of the elderly was 2.67mm/month.There was no difference in nail growth between the left and right hands.Nail growth of per finger was significantly slower in older people than in younger people(n = 64,p = 0.03).Conclusion: The nail growth rate of the elderly is significantly lower than that of the young.