Clinical Study Of Pituitary Hormones And MRI Features In Patients With Hypoxic-ischemic Encephalopathy

Background and ObjectiveA newborn with neonatal asphxia cannot establish normal breathing due to various causes at perinatal neonatal birth, including hypoxia and acidosis; furthermore, severe cases can lead to multiple organ damage in a pathophysiological situation due to the hypoxia. When the brain is supplied insufficient blood, it can show convulsions, changes in consciousness, abnormal muscle tone and other symptoms, known as hypoxic-ischemic encephalopathy. There are 1800-2000 million live newborns per year in China and the incidence of asphyxia is 13.6%, with varying degrees of disability at 15.6%. What results is not only neurological symptoms such as cerebral palsy, learning and memory disorders, but also permanent endocrine changes such as long term pituitary dysfunction.Some researchers even believe that 5 0-60% pituitary dysfunction has perinatal asphyxia or breech birth and other abnormal childbirth history.Hypopituitarism is one or more of the pituitary hormone deficiency, accompanied by pituitary height decreased, small pituitary, posterior pituitary ectopic or absent (EPP),Pituitary stalk agenesis (PSA),. pituitary stalk thinning·and interrupted or even disappear and other pituitary morphological changes..We investigated pituitary hormone levels after hypoxic-ischemic encephalopathy and combined it with pituitary MRI imaging studies in an effort detect and intervene on pituitary dysfunction in children early in order to prevent an impact on quality of life.Hypoxic-ischemic encephalopathy is more secondary to the damage caused by asphyxia. We did not fully grasp these changes in mechanism of hormones and their role.We will process a correlational analysis whether or not the pituitary hormone level changes cause pituitary morphological changes, such as pituitary volume, pituitary signal,pituitary height. There are few reports for the normal data on the pituitary meridians in the neonatal field.In addition to the well-known endocrine function, pituitary hormones in the body are involved in immune regulation, neuroprotection, and water balance. We will further explore the role of neuroprotection. In the past 20 years, prolactin, one of pituitary hormone, was paid more attention because of wide ranges of roles and effect on the growth hormone, such as promoting growth and development. Prolactin is a protein hormone secreted by the pituitary gland cells. It is in the same family with growth hormone (GH), placental prolactin, and proliferating protein (Proliferin). These hormones have similar structure and similar biological effects, which can affect the growth and development, reproductive endocrine, immune regulation. Prolactin binds to its receptors,activates signal transduction pathways, and interacts with other signal transduction pathways of various hormones and receptors, resulting in complex biological effects.We cultured hippocampal neurons and observed the effect of prolactin on MAPK and PI3K / AKT cell signaling pathways in neuronal cells. It will inspire us to find molecular targets for the treatment of hypoxic-ischemic encephalopathy through more understanding of prolactin.Part One The dynamic changes of anterior pituitary hormones of hypoxic-ischemic encephalopathyObjectiveTo investigate the change of hormone in anterior pituitary of neonatal hypoxic-ischemic encephalopathy (HIE) and its significance.MethodsEighty children with neonatal asphyxia who were hospitalized from May 2013 to May 2015 in our hospital were enrolled for observation. They were classified into three groups based on the HIE diagnosis standard developed by the Chinese Medical Association in 2005: mild group (N = 35),moderate group (n = 25) and severe group (n=20). 30 cases of patients with neonatal pneumonia were kept for the same period of hospitalization as a control. Growth hormone (GH) and insulin-like growth factor (IGF-1)in the hypothalamus-pituitary-growth hormone axis were measured in the blood samples taken at 6 hours, 48 hours, and 7 days after admission. The levels of Thyroid-stimulating hormone (TSH), free triiodothyronine (FT3) and Free thyroxine (FT4) in the hypothalamus-pituitary-thyroid axis and the content of Follicle-stimulating hormone(FSH), Luteinizing hormone (LH), Prolacin (PRL), Estradiol (E2), and Testosterone(T) in the hypothalamus-pituitary-gonadal axis were measured using an ELISA test.The levels of hormones were analyzed statistically, and the levels of hormones at different time points were analyzed dynamically.Of the 80 patients, 2 died in the moderate and severe groups, 78 cases were followed up and evaluated by Gesell scale at 3 months, and according to the results, the patients were divided into two groups: the poor prognosis group and the eusemia group, and the pituitary hormone levels, GH, TSH, LH, FSH, ACTH and PRL. Then comparison between the two groups was performed.Results80 cases of HIE and 30 cases of control group were included in the results analysis.1. The change of growth hormone axis: In the acute stage (6h), the GH of the severe group was significantly lower than that of the mild and moderate group and the control group. GH and IGF-1 in HIE children in moderate and severe group were significantly lower than those in mild and control groups at 48h and 7d (P <0.05). Furthermore,there was significant difference between the severe group and the moderate group (P<0.05). There was no significant difference between the mild and the control group(P>0.05).2. The changes of thyroid axis, TSH, FT3, and FT4 in the acute severe group were significantly lower than those in mild to moderate groups as well as the control group.There was no significant difference between mild and moderate group and control group.After 7 days, the severe group was still significantly lower than the control group;meanwhile, the mild to moderate group and the control group had no difference.3. Changes in gonadal axis: FSH and LH decreased at 6 hours after birth, and the difference was significant (P<0.05) between the mild group and the moderate group.There was no significant difference between the mild, severe groups and the control group (P> 0.05). The PRL in the acute stage (6 h) in the severe group was significantly higher than that in the mild-moderate group and the control group (P <0.05). After 7 days,the severe group was still significantly higher (P <0.01) than the moderate and the control group. The moderate group in the 6h, 48 days was higher than the control group, however,there were no significant differences at 7 days. E2, P, T in the three groups at all times with the control group showed no significant difference.4.In follow-up, after 3 months in the two groups, the changes of GH, TSH and LH were significantly lower than those in the control group, while PRL increased. These hormones have got predictive value for prognosis.Conclusions1. Asphyxia in children has various degrees of anterior pituitary hormone secretion disorder. At early stages, severe asphyxia causes significant hormone changes, and the recovery is slow, it is valuable in detect the hormone changes. Monitoring of changes in hormone levels may help to assess the prognosis.2. To the growth hormone axis, the GH increased at first, than decreased, GH is a stress hormone. IGF-1 decreased a lot and has a relationship with the severity of the disease.3. To the gonadal axis, PRL increased and has a relationship with the severity of the disease.4. To the thyroid axis, TSH and FT4 are mainly inhibited.5. In follow-up, after 3 months in the two groups, the changes of GH, TSH and LH were significantly lower than those in the control group, while PRL increased. These hormones have got predictive value for prognosis.Part Two The pituitary MR features of hypoxic-ischemic encephalopathyObjectiveTo study the pituitary morphology, volume, signal intensity of anterior pituitary of newborn infants with hypoxic-ischemic encephalopathy (HIE), and to analyze the relationship with pituitary hormone.MethodsEighty children with neonatal asphyxia who were hospitalized from May 2013 to May 2015 in our Hospital were enrolled for observation. They were classified into three groups based on the criteria of HIE developed by the Chinese Medical Association in 2005: mild group (N = 35), moderate group (n = 25) and severe group (n = 20). 30 cases of patients without endocrine disease and history of intrauterine distress were kept for the same period of hospitalization as a control.Pituitary MRI was performed 7-10 days after birth. Brain examination was performed using a Siemens Avanto 1.5T magnetic resonance scanner. The pituitary height,the anterior pituitary diameter, the anterior pituitary signal intensity and Nucleus olivaceus signal intensity ratio at the same layer were measured in the T1WI sequence pituitary median sagittal level. The pituitary coronal width and height were measured at the coronal plane, and the pituitary volume was calculated by the formula ?/ 6× (anterior pituitary diameter × coronal height × coronal width).ResultsTwo patients were rulled out in severe group.1.There was no significant effect on neonatal pituitary shape. The shape is convex in 88.5% in mild and 88% in moderate, 88.8% in severe HIE patients.2. There are no significant differences for Pituitary volume in HIE groups compared with the control group.3. There are no no significant differences for the ratio of pituitary anterior lobe signal intensity and pons compared with the control group in mild and moderate group.In severe group the signal decreased, There is a significant difference between the severe and other three groups.Conclusions:1.There was no significant effect on neonatal pituitary shape.2. There was no significant effect on neonatal pituitary volume and anterior pituitary signal intensity for mild to moderate hypoxic-ischemic encephalopathy.3. Severe hypoxic-ischemic encephalopathy may be associated with pituitary anterior pituitary signal decline.Part Three Protective Mechanism of PRL on neuron through regulation of MAPKs and AKT pathwaysObjective:It is reported that prolactin can promote the nerve regeneration and repair, and has the potential for treatment of brain ischemia injury in rats/mice by regulating the MAPKs and AKT signaling pathways,which is emerging as novel neuroprotective agent.However, the mechanism remains unclearly. The aim of the present study is to culture therat neuron and explore the regulating mechanism of prolactin on MAPKs and AKT signaling pathways.Methods:1. To culture the rat hippocampal neurons and primary neuron of rat hippocampus in vitro.2. MTT method was used to determine the HT22 cells viability, and evaluate the protective mechanism of PRL against oxygen glucose deprivation (OGD)-induced neurotoxicity.3. Western blotting method was employed to examine the expression of MAPKs and AKT signal pathways.Results:1. MTT results showed that prolactin (12.5-800 ng/ml) showed no significant cell cytotoxicity towards HT22 cells. There is no obvious change in cell morphology, cell number and the connection between the cells. Moreover, PRL showed no significant neurotoxicity on primary neurons. And, pretreatment with PRL effectively inhibited OGD-induced cell killing in the primary neurons, improved the neuron morphology.2. Western blotting results showed that prolactin dose- and time-dependent activated MAPKs pathway, as convinced by the constant activation of p-ERK in 90 min. The phosphorylation of JNK and p38 was not detected in prolactin-treated cells. Prolactin also time- and dose-dependent triggered the p-AKT activation and attenuates OGD-induced inhibition against p-AKT and p-ERK expression. However, addition of MEK/ERK inhibitor and PI3K/AKT inhibitor further confirmed the role of prolactin in MAPKs and AKT signaling pathways.Conclusion:Prolactin exhibited notable neuroprotective effect on neurons through a sustained activation of MAPKs and AKT signaling pathways, indicating that prolactin as a novel neuroprotective agent maybe inhibit the neuron apoptosis and promote the neuron repair through regulating the phosphorylation of MAPKs and AKT signaling.