Proteomics in obstetrics and gynecology.

The Human Genome Project had made the scientific community and public believe that all biology and medicine would become understandable after the sequencing of the DNA. As biology is much more complicated than the structure and function of nucleic acids, the practical applications are quite limited. The study of living systems has now expanded past genomics based on the rationale that it is the protein products of the gene and not simply gene expression that have effects and cause disturbances at the cellular level. Its advent has provided the hope of discovering novel biological markers for use in the screening, early diagnosis and prediction of response to therapy.[ 1 ] Mass spectrometers (MSs) like matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) MS, surface-enhanced laser desorption/ionization time of flight (SELDI-TOF) MS, electro spray ionization MS and Fourier transform ion cyclotron resonance MS have enabled the study of molecular mechanisms of cancer with complex fluids and tissue samples with a good sensitivity and resolution. Proteomic technologies like two-dimensional (2D) polyacrylamide gel electrophoresis (PAGE), isotope-coded affinity tags, SELDI-TOF, multidimensional protein identification technology, protein arrays and protein chips promise application at the bedside for discovering protein patterns that distinguish disease from disease-free states with a high sensitivity and specificity.[ 2 ]

Looking back, it seems that the major outcome of human genome sequencing has finally been to open the way to exploration of the proteome. Perhaps the most promising outcome of the work reported by scientists is the interface between proteomic technology and bioinformatics. The rapid explosion in the amount of data being generated by current genomic and proteomic technology already exceeds the analytical capacity of the human mind. The need for increasing sophistication in data management and statistical interpretation and attention to this aspect of research is critical to its successful translation into clinical practice.[ 27 ]

Pre-eclampsia is a pregnancy-specific syndrome and a major cause of maternal mortality. The pathophysiology of pre-eclampsia is unknown and no proteome analysis is reported. Watanabe et al . sought to identify proteins associated with pre-eclampsia using 2D electrophoresis on sera of six patients with pre-eclampsia and six normal pregnant women, followed by comparison of the profiles. Clusterin was identified by MALDI-TOF-MS followed by peptide mass fingerprinting, a protein database search and Western blot analysis.[ 16 ] Mine and colleagues found dynactin, a protein related to cell turnover in placental proteome maps, by novel 2D-immunoblotting analysis.[ 17 ] Myers et al . carried out a pilot study to use protein chip technology to determine differences in protein profiles in plasma taken at 26 weeks from women at risk of developing pre-eclampsia. They found five proteins upregulated significantly in samples from women who subsequently developed pre-eclampsia compared with women who remained normotensive.[ 18 ] Recent evidence suggests that a major cause of prematurity-associated neonatal pathology is the fetal and neonatal response to inflammation or infection rather than respiratory distress syndrome, intraventricular hemorrhage, necrotizing enterocolitis and bronchopulmonary dysplasia as the primary causes of pre-term delivery. Proteomic profiling of amniotic fluid provides a precise means for detection of inflammation by revealing the presence of four biomarkers (defensins-2 and 1, Calgranulin C and A) that are highly predictive of intrauterine inflammation (MR score). MR score presents a gradient of disease activity progressing from “absent,” “mild” to “severe” inflammation. Thus, it provides the ability to identify patients who might benefit from interventions in utero in a modern diagnostic–therapeutic framework.[ 19 ] Proteomic tools are being applied in varied fields related with reproductive function, such as the study of oocyte maturation, spermatogenesis and fertilization in mammals.[ 20 – 23 ] The identification of specific genes in oocytes and embryos is now possible with the use of powerful tools such as library analysis or subtractions, DNA array, comparative analysis of databanks from other mammals and 2D-gel electrophoresis analysis. Finally, RNA interference is a useful tool for studying gene function by knocking out the activity of specific genes, and will be used in oocytes and embryos.[ 24 ] Amniotic fluid is a potential source of biomarkers for many disorders that may occur during pregnancy or for embryonic abnormalities. Proteomics have already been applied in the analysis of tissues from fetuses with Down's syndrome.[ 25 ] The proteomic analysis of follicular fluid by Angelucci et al . revealed identification of a large number of acute phase proteins, including transferrin, ceruloplasmin, afamin, hemopexin, haptoglobin and plasma amyloid protein, suggesting the hypothesis that mammalian ovulation can be compared with an inflammatory event. Several important antioxidant enzymes, i.e. catalase, superoxide dismutase, glutathione transferase, peroxisonase, heat shock protein 27 and protein disulfide isomerase, were also identified. This indicates that, during maturation, the human follicle is well protected against toxic injury due to oxidative stress.[ 26 ]