Mesenchymal stem cell treatment for peripheral nerve injury:a narrative review

Peripheral nerve injuries occur as the result of sudden trauma and lead to reduced quality of life.The peripheral nervous system has an inherent capability to regenerate axons.However,peripheral nerve regeneration following injury is generally slow and incomplete that results in poor functional outcomes such as muscle atrophy.Although conventional surgical procedures for peripheral nerve injuries present many benefits,there are still several limitations including scarring,difficult accessibility to donor nerve,neuroma formation and a need to sacrifice the autologous nerve.For many years,other therapeutic approaches for peripheral nerve injuries have been explored,the most notable being the replacement of Schwann cells,the glial cells responsible for clearing out debris from the site of injury.Introducing cultured Schwann cells to the injured sites showed great benefits in promoting axonal regeneration and functional recovery.However,there are limited sources of Schwann cells for extraction and difficulties in culturing Schwann cells in vitro.Therefore,novel therapeutic avenues that offer maximum benefits for the treatment of peripheral nerve injuries should be investigated.This review focused on strategies using mesenchymal stem cells to promote peripheral nerve regeneration including exosomes of mesenchymal stem cells,nerve engineering using the nerve guidance conduits containing mesenchymal stem cells,and genetically engineered mesenchymal stem cells.We present the current progress of mesenchymal stem cell treatment of peripheral nerve injuries.

Gastric mucosal precancerous lesions in Helicobacter pyloriinfected pediatric patients in central China:A single-center,retrospective investigation

BACKGROUND Helicobacter pylori(H.pylori)infects about 50%of the world population and is the major cause of chronic gastritis,peptic ulcers,and gastric cancer.Chronic H.pylori infection induces gastric mucosal precancerous lesions mostly in adulthood,and it is debatable whether these pathological conditions can occur in childhood and adolescents as well.Since this is a critical issue to determine if intervention should be offered for this population group,we investigated the gastric mucosal precancerous lesions in pediatric patients in an area in central China with a high prevalence of H.pylori and gastric cancer.AIM To investigate the relationship of H.pylori infection and gastric mucosal precancerous lesions in children and adolescents in central China.METHODS We screened 4258 ward-admitted children and adolescent patients with upper gastrointestinal symptoms,and finally enrolled 1015 pediatric patients with H.pylori infection and endoscopic and histological data.H.pylori infection status was determined by rapid urease test and histopathological examination.Both clinical and pathological data were collected and analyzed retrospectively.Occurrence of gastric mucosal precancerous lesions,inflammatory activity and degree of inflammatory cell infiltration between H.pylori-positive and-negative groups were compared.RESULTS Among the 1015 eligible children and adolescents,the overall H.pylori infection rate was 84.14%(854/1015).The infection rate increased with age.The incidence of gastric mucosal precancerous lesions in H.pylori-infected children was 4.33%(37/854),which included atrophic gastritis(17 cases),intestinal metaplasia(11 cases)and dysplasia(9 cases).In H.pylori-negative patients,only 1 atrophic gastritis case[0.62%,(1/161)]was found(P<0.05).Active inflammation in H.pyloriinfected patients was significantly higher than that in non-infected patients,and the H.pyloriinfected group showed more severe lymphocyte and neutrophil granulocyte infiltration(P<0.001).In addition,endoscopy revealed that the most common findings in H.pylori-positive patients were antral nodularity,but in H.pylori-negative patients only superficial gastritis was observed.CONCLUSION In children and adolescents,gastric mucosal precancerous lesions occurred in 4.33%of H.pyloriinfected patients in central China.These cases included atrophic gastritis,intestinal metaplasia,and dysplasia.The data revealed an obvious critical issue requiring future investigation and intervention for this population group.

Necrostatin-1 protection of dopaminergic neurons

Necroptosis is characterized by programmed necrotic cell death and autophagic activation and might be involved in the death process of dopaminergic neurons in Parkinson＇s disease. We hypothesized that necrostatin-1 could block necroptosis and give protection to dopaminergic neurons. There is likely to be crosstalk between necroptosis and other cell death pathways, such as apoptosis and autophagy. PC12 cells were pretreated with necroststin-1 1 hour before exposure to 6-hydroxydopamine. We examined cell viability, mitochondrial membrane potential and expression patterns of apoptotic and necroptotic death signaling proteins. The results showed that the autophagy/lysosomal pathway is involved in the 6-hydroxydopamine-induced death process of PC12 cells. Mitochondrial disability induced overactive autophagy, increased cathepsin B expression, and diminished Bcl-2 expression. Necrostatin-1 within a certain concentration range（5–30 μM） elevated the viability of PC12 cells, stabilized mitochondrial membrane potential, inhibited excessive autophagy, reduced the expression of LC3-II and cathepsin B, and increased Bcl-2 expression. These findings suggest that necrostatin-1 exerted a protective effect against injury on dopaminergic neurons. Necrostatin-1 interacts with the apoptosis signaling pathway during this process. This pathway could be a new neuroprotective and therapeutic target in Parkinson＇s disease.