The Screening And Study Of The Differentially Expressed Genes In Adrenal Hyperplasia And Cortical Adenoma

Background and Objective:Primary aldosteronism is one of the most reason of symptomatichypertension, recently using the ratio of plasma aldosteroneconcentration (PAC) to PRA as the screening test for primary aldosteronismin hypertensive populations suggested that the prevalence may be as highas 5-13% in Asia, and in Europe the the prevalence may be as high as5-25%. The most common clinical subtypes of primary atdosteronism arealdosterone-producing adrenocortical adenoma (APA) and adrenal corticalhyperplasia (or idiopathic hyperaldosteronism, IHA). The patients of APAcan be cured by operation. But the patients of IHA should be treated byboth drug treatment and operation,. and the recurrence rate of IAH is alsovery high. So the discrimination of these two disease has very importantsignificance in clinic. The clinical manifestation of these two diseasesboth are high blood pressure, hyperaldosteronemia, and hypokalemic, so itmade the clinic diagnos difficultly. At present, we only depend onbiochemical indicator in laboratory, imageology and the pathobiology ofspecimen after operation to discriminate these two diseases. Because theyhave highly discrimination in pathematology, we think that theetiological factors of these two diseases must be induced by diferencegenes. Following the qickly development of the empirical method,especially human genome project overall done, one of the most topic inmolecular biology are using GeneChip technology to find the differentexpressed genes. This technology have features of high sensitivity. highspecificity, reliable results, and high repeatability, so it must bequickly drived off and cloned the different expressed genes inaldosterone-producing adrenocortical adenoma and adrenal corticalhyperplasia. These genes would help us finding the molecular biology ofthe effluence and the development in these two diseases, and they also have very important significance in the diagnosis, the differentialdiagnosis and the treatment in clinic, especially we could find newhealing methods of adrenal cortical hyperplasia that could not completelytreat by the f drug and operation, finally we can effectually reduce therecidivation of this disease.Methods:Oligonucleotide microarray, which contained probe sets for 22kknown human genes, were made to investigate the gene expression profileof aldosterone-producing adrenocortical adenoma and adrenal corticalhyperplasia. Firstly total RNA was isolated from the tissues ofaldosterone-producing adrenocortical adenoma and adrenal corticalhyperplasia, then synthesis and labeling of cDNA were achieved by directincoporation of Cy3-dUTP in a reverse transcription reaction using totalRNA, the Cy3-1abeledcDNA of aldosterone-producing adrenocortical adenomaand adrenal cortical hyperplasia was respectively hybridizated to amicroarray. Finally the hybridized slides were scanned with ScanArrayExpress scanner and scanned image files were analyzed with GenePix Pro4.0 software. We removed the genes that were undetectable in all samples.Statistical analysis was normalization by using Lowess. Only up anddown-regulated genes with a significant difference in fluorescencebetween aldosterone-producing adrenocortical adenoma (or adrenalcortical hyperplasia were selected) and normal adrenal gland wereselected. Then we selected the genes exhibiting a≥2-fold expressionchange in aldosterone-producing adrenocortical adenoma (or adrenalcortical hyperplasia samples) and normal adrenal gland, and then rankedthem in terms of their over and down-expression. At last, these twodiseases were compared with the same normal adrenal gland, so we couldcompare the aldosterone-producing adrenocortical adenoma to adrenalcortical hyperplasia by using these data.Results:In our experiment, we find 333 differently expressed genes between aldosterone-producing adrenocortical adenoma and normal adrenal gland,in these genes, there are 118 up-regulated genes and 215 down-regulatedgenes; at the same time, we also find 113 differently expressed genesbetween adrenal cortical hyperplasia and normal adrenal gland, in thesegenes, there are 49 up-regulated genes and 84 down-regulated genes. Bythe computer analysis and literature retrieval, we also screen thedifferently expressed genes between aldosterone-producingadrenocortical adenoma and adrenal cortical hyperplasia, these genes canbe divided into some functional categories, which include the genes ofgrowth factor, cytokine, acceptor family and tumor suppressor gene, andthe mechanism of action of these genes in the happening and developmentof these two diseases need more investigation.Conclusions:1. There are many different genes between aldosterone-producingadrenocortical adenoma and adrenal cortical hyperplasia tissue in primaryaldosteronism. Microarray can be used effiectively to find outdifferently expressed genes in aldosterone-producing adrenocorticaladenoma and adrenal cortical hyperplasia.2. Thedifferent genesthat screened are decide by analysis, it is veryuseful for us of understanding the function of these genes. For example,(1)There are many genes such as STAR, CYP11B,MCR2 that control thealdosterone; (2) By using immunohistochemistry, we would use KDR todiscriminate the different between aldosterone-producing adrenocorticaladenoma and adrenal cortical hyperplasia in histological anatomy. So theyhave very important significance of investigating the happening anddevelopment of aldosterone-producing adrenocortical adenoma and adrenalcortical hyperplasia in primary aldosteronism, and they also use indiagnosis, differential diagnosis and prognosis of these diseases.3. We firstly found the cDNA Lib by the different genes that screenedin this investigation in primary aldosteronism, it has importantsignificance to investigate primary aldosteronism and the subtypes of aldosterone-producing adrenocortical adenoma and adrenal corticalhyperplasia in primary aldosteronism. It gives us great scientificresearch information to investigate the diseases.