Immuno-based detection of extracellular vesicles in urine as diagnostic marker for prostate cancer.

Extracellular vesicles (including the subclass exosomes) secreted by cells contain specific proteins and RNA that could be of interest in determining new markers. Isolation/characterization of PCa-derived exosomes from bodily fluids enables us to discover new markers for this disease. Unfortunately, isolation with current techniques (ultracentrifugation) is labor intensive and other techniques are still under development. The goal of our study was to develop a highly sensitive time-resolved fluorescence immunoassay (TR-FIA) for capture/detection of PCa-derived exosomes. In our assay, biotinylated capture antibodies against human CD9 or CD63 were incubated on streptavidin-coated wells. After application of exosomes, Europium-labeled detection antibodies (CD9 or CD63) were added. Cell medium from 37 cell lines was taken to validate this TR-FIA. Urine was collected (after digital rectal exam) from patients with PCa (n = 67), men without PCa (n = 76). As a control, urine was collected from men after radical prostatectomy (n = 13), women (n = 16) and patients with prostate cancer without digital rectal exam (n = 16). Signal intensities were corrected for urinary PSA and creatinine. This TR-FIA can measure purified exosomes with high sensitivity and minimal background signals. Exosomes can be measured in medium from 37 cell lines and in urine. DRE resulted in a pronounced increase in CD63 signals. After DRE and correction for urinary PSA, CD9 and CD63 were significantly higher in men with PCa. This TR-FIA enabled us to measure exosomes with high sensitivity directly from urine and cell medium. This TR-FIA forms the basis for testing different antibodies directed against exosome membrane markers to generate disease-specific detection assays.

Cardiac troponin I in congenital heart defects with pressure or volume overload.

OBJECTIVE: To evaluate the prevalence of cardiac troponin I (cTnI) and autoantibodies to cTn in children with congenital heart defects with volume or pressure overload fulfilling the criteria for treatment, and in healthy children. DESIGN: The study groups comprised 78 children with volume overload caused by an atrial septal defect or a patent ductus arteriosus, and 60 children with pressure overload caused by coarctation of the aorta or stenosis of the aortic or the pulmonary valve, and 74 healthy controls. Serum levels of natriuretic peptides, cTnI, and autoantibodies to cTn were analyzed at baseline, prior to treatment and in 64 patients 6 months after treatment. RESULTS: At baseline, one child with volume overload, 12 children with pressure overload, and one healthy control had positive cTnI. Further analysis of the pressure overload subgroup revealed that the children with positive cTnI were younger than those with negative cTnI, and had higher levels of natriuretic peptides. The pressure gradient at the coarctation site or stenotic valve was higher in those with positive TnI. Six months after treatment, 63 of 64 children examined were cTnI negative. CONCLUSIONS: The cTnI release is more frequently associated with pressure than volume overload which resolves after treatment in most children.