Neurotrophin Mediated Acid-sensing Ion Channels Gene Expression And Its Peripheral Sensitization Function In Gastroeshophageal Reflux Diseases

ObjectiveTestify the elevation of ASICs and NT family expression in the inflamed human esophagus.And investigate the correlation of acid-sensing ion channels and neurotrophins in GERDpatients.MethodsBetween January and July2013,43patients with erosive esophagitis entered the study.16healthy controls were also included in this study. GERDQ questionnaires were filled by all theparticipants and were analyzed. Biopsies were taken from the distal esophagus of43patientswith erosive GERD, and of16healthy controls. According to the LA classification, all43patients were seperated into two groups, group SR (SSC) with15LA grade B, C or D patients,group MR with28LA grade A patients. We assessed the biopsies with real-time quantitativepolymerase chain reaction for ASIC1，ASIC3，NGF，BDNF，GDNF，NT3，NT4，and P75.Immunohisto-chemical analysis was used to determine the expressions of ASIC1and P75protein. We investigated the correlation of acid-sensing ion channels and neurotrophins inGERD patients.ResultsGERDQ:With group SR(SSC) GERDQ9.0±1.48，group MR GERDQ6.5±1.39，group C GERDQ1.5±1.31，the differences among patient-groups were not statistically significant, but the GERDQmedian of group C was the lowest(P<0.05). Using GERDQ6.5as the cut-off line for GERDdiagnosis, the sensitivity was58.1%，and the specificity93.7%.Real Time-PCR:The mRNA expression was showed as follows. ASIC1mRNA expressions of group SR aswell as group MR were higher than group SSC and group C(P＜0.05, SR36.527±34.912SSC5.413±4.215, MR21.242±14.325, C4.404±2.938). ASIC3mRNA expression of groupSR was the greatest, followed with group MR while ASIC1mRNA expressions of groupMR and SSC were relatively low(P＜0.05, SR5.200±4.343, SSC0.419±0.349, MR1.137±0.660, C0.352±0.164＝.Expressions of NGF gene were higher in group SR(0.979±0.300) and SSC (0.405±0.261). Expressions of NGF gene were lower in group MR(1.742±0.986) and group C (0.462±0.400)(P<0.05). P75, with group SR43.425±25.603，SSC12.907±6.756，MR36.550±19.894，C10.086±5.681，was much more expressed ingroup SR and MR than the other two groups(P<0.01).BDNF (SR0.651±0.646，SSC0.212 ±0.209，MR0.150±0.107，C0.167±0.108) expression of group SR was higher than allother groups(P<0.05), there were no significant differences among group SSC, MR and C.GDNF, with group SR8.967±8.783，SSC2.915±2.828，MR3.784±1.307，C7.494±6.326，was much more expressed in group SR than the other groups(P<0.05), there werealso no significant differences among group SSC, MR and C.Both of NT3(SR10.500±7.673，SSC6.254±6.044，MR6.467±4.167，C8.744±6.973) and NT4(SR13.796±7.575，SSC6.995±2.336，MR6.252±3.082，C9.816±7.270) mRNA levels showed nodifferences among groups(P>0.05).Pearson correlation coefficients of ASIC1and ASIC3，P75，NGF，BDNF mRNA were0.772，0.693，0.587，0.578. Pearson correlation coefficientsof ASIC3and ASIC1，P75，NGF，BDNF mRNA were0.772，0.658，0.654，0.604.Immunofluorescence:The optical density of the ASIC1-immunostained sections and P75-immunostained sectionsof esophageal biopsies taken from4groups are showed below. ASIC1protein was higher ingroup SR（0.100±0.018） and MR（0.107±0.012）, and lower in group SSC （0.053±0.007）and C（0.048±0.006）(P<0.01). The optical densities of the P75protein levels wassignificantly greater in group SR（0.075±0.006） and MR（0.075±0.004）, and lighter ingroup SSC （0.055±0.007）and C（0.055±0.007）(P<0.01). Pearson correlation coefficientof ASIC1and P75protein was0.705.ConclusionWhen using GERDQ to diagnose GERD for Chinese, the cut-off line should be lower than8.Further studies are necessary in order to better apply it in China. The expressions of ASICs,NGF, BDNF, GDNF, and P75were significantly increased in GERD patients. All theresults support the association of P75and NT family in the up-regulation of ASIC1inpatients with erosive esophagitis.