RESUMO
Hypoxia-inducible factor-1α (HIF-1α)is a transcription factor that acts as a master regulator of gene expression induced by low oxygen conditions.HIF-1α is the most sensitive indicator of hypoxia and can be activated by systemic hypoxia,cerebral hemisphere ischemia and cerebral focal ischemia.HIF-1 expression can be induced by hypoxic-ischemic damage after cerebral infarction and exert its effects on hypoxia-inducible downstream genes,thus protecting hypoxic tissues and cells under hypoxic conditions via regulating the expression of its downstream target genes.This article reviews the expression of HIF-1α and its downstream target genes in acute cerebral ischemia,in order to provide a theoretical basis for gene therapy.
RESUMO
Objective To explore the relationship between condition of hypoxia and prognosis in patient with renal clear cell carcinoma (RCCC).Methods The expression of hypoxia-inducible factor-lo( HIF-1 α) protein in cancer tissue of 89 RCCC cases was examined by streptavidin-biotin complex immunohistochemistry.Clinical and pathological data and prognosis of 89 cases were analyzed retrospectively.There were 66 males and 23 females,with an average age of 57 years.The patients were divided into two groups,the chronic pulmonary disease (CPD) group ( 19 cases) and non CPD (NCPD) group (70 cases),with 46cases in clinical stage I,15 cases in stage Ⅱ,26 cases in stage Ⅲ,and 2 cases in stage Ⅳ.The relationship between survival time and clinicopathological variables including the presence of CPD,the positive rate of HIF-1α protein,smoking history and hemoglobin level were evaluated by the Kaplan-Meier method.And the Cox proportional hazards regression model was build to analyze the correlation between each variable and survival time.Results The 89 cases were followed up for a median time of 19 months (6 to 84 months).Twenty cases died,and 69 cases survived.Between the CPD group and NCPD group,clinical stage,hemoglobin level and the degree of expression of HIF-1 α were significantly different (P ＜ 0.05 ).The median survival time was 44 and 71 months in CPD group and NCPD group,respectively,and the difference was significant ( P ＜ 0.05 ).The median survival time was 43 and 70 months in Hb≤ 110 g/L group and Hb ＞ 110 g/L group,respectively,and the difference was significant ( P ＜ 0.05).The stronger the degree of expression of HIF-lα was,the shorter the overall survival was.And the difference was significant ( P ＜0.05 ).Associated with CPD,hemoglobin level,the expression of H1F-1α were independent factors affecting overall survival of the patients (P ＜0.05 ).CPD and HIF-1 α expression were positively related to disease-free survival time,and hemoglobin level was negatively related to disease-free survival time.Conclusions Systemic hypoxia caused by CPD may aggravate the hypoxie state in the organization of the patients with RCCC.The condition of hypoxia and prognosis in patient with RCCC is negatively correlated.
RESUMO
Hypoxia-induciole factor-1 (HIF-1) is an important transcription factor.It participates in the body's response to the hypoxic environment mainly through its active subunit HIF-1α.During cerebral ischemia and hypoxia,the expression of HIF-1α is upregulated and may activate the expressions of multiple downstream target genes involving glycolysis,vascular growth,cell survival and apoptosis.It has an important significance for the improvement of energy metabolism and the establishment of microcirculation after cerebral ischemia.HIF-1α can not only promote the neuronal survival,but also mediate delayed neuronal death.A variety of preconditioning and postconditioning methods may regulate the survival and death of neuronal cells by activating HIF-1α.