Quantification of HPV16 E7 Oncoproteins in Urine Specimens from Women with Cervical Intraepithelial Neoplasia.

We present the validity of using an ultrasensitive enzyme-linked immunosorbent assay (ELISA) for quantifying high-risk human papillomavirus (HPV) 16 E7 oncoproteins in urine specimens as a noninvasive method of analyzing the oncogenic activity of HPV. Some reports claim that the oncogenic activity of HPV is a more relevant clinical indicator than the presence of HPV DNA for estimating malignant potential. In the present study, urine containing HPV16 and related types were selected by uniplex E6/E7 polymerase chain reaction and classified according to the pathologic diagnosis of cervical intraepithelial neoplasia (CIN) in cervical biopsy specimens. Our ultrasensitive ELISA was able to detect attomole levels of HPV16 E7 oncoproteins, and it detected HPV16-positive SiHa cells at >500 cells/mL without detecting HPV18-positive cells. Our ELISA results showed E7 oncoproteins in 80% (4/5) of urine specimens from women with HPV16-positive CIN1, 71% (5/7) of urine specimens from CIN2 patients, and 38% (3/8) of urine specimens from CIN3 patients. Some urine specimens with undetectable E7 oncoproteins were thought to be negative for live HPV 16-positive cells or in an inactivated state of infection. These results provide the basis for assessing oncogenic activity by quantifying E7 oncoproteins in patient urine.

Ultrasensitive ELISA Developed for Diagnosis.

For the diagnosis of disease, the ability to quantitatively detect trace amounts of the causal proteins from bacteria/viruses as biomarkers in patient specimens is highly desirable. Here we introduce a simple, rapid, and colorimetric assay as a de novo, ultrasensitive detection method. This ultrasensitive assay consists of a sandwich enzyme-linked immunosorbent assay (ELISA) and thionicotinamide-adenine dinucleotide (thio-NAD) cycling, forming an ultrasensitive ELISA, in which the signal substrate (i.e., thio-NADH) accumulates in a triangular manner, and the accumulated thio-NADH is measured at its maximum absorption wavelength of 405 nm. We have successfully achieved a limit of detection of ca. 10-18 moles/assay for a target protein. As an example of infectious disease detection, HIV-1 p24 could be measured at 0.0065 IU/assay (i.e., 10-18 moles/assay), and as a marker for a lifestyle-related disease, adiponectin could be detected at 2.3 × 10-19 moles/assay. In particular, despite the long-held belief that the trace amounts of adiponectin in urine can only be detected using a radioisotope, our ultrasensitive ELISA was able to detect urinary adiponectin. This method is highly versatile because simply changing the antibody enables the detection of various proteins. This assay system requires only the measurement of absorbance, thus it requires equipment that is easily obtained by medical facilities, which facilitates diagnosis in hospitals and clinics. Moreover, we describe an expansion of our ultrasensitive ELISA to a non-amplification nucleic acid detection method for nucleic acids using hybridization. These de novo methods will enable simple, rapid, and accurate diagnosis.

Urinary adiponectin as a new diagnostic index for chronic kidney disease due to diabetic nephropathy.

Objective: The chronic kidney disease (CKD) is widely diagnosed on the basis of albuminuria and the glomerular filtration rate. A more precise diagnosis of CKD, however, requires the assessment of other factors. Urinary adiponectin recently attracted attention for CKD assessment, but evaluation is difficult due to the very low concentration of urinary adiponectin in normal subjects. Research design and methods: We developed an ultrasensitive ELISA coupled with thionicotinamide-adenine dinucleotide cycling to detect trace amounts of proteins, which allows us to measure urinary adiponectin at the subattomole level. We measured urinary adiponectin levels in 59 patients with diabetes mellitus (DM) and 24 subjects without DM (normal) to test our hypothesis that urinary adiponectin levels increase with progression of CKD due to DM. Results: The urinary adiponectin levels were 14.88±3.16 (ng/mg creatinine, mean±SEM) for patients with DM, and 3.06±0.33 (ng/mg creatinine) for normal subjects. The threshold between them was 4.0 ng/mg creatinine. The urinary adiponectin levels increased with an increase in the CKD risk. Furthermore, urinary adiponectin mainly formed a medium-molecular weight multimer (a hexamer) in patients with DM, whereas it formed only a low-molecular weight multimer (a trimer) in normal subjects. That is, the increase in urinary adiponectin in patients with DM led to the emergence of a medium-molecular weight form in urine. Conclusions: Our new assay showed that urinary adiponectin could be a new diagnostic index for CKD. This assay is a non-invasive test using only urine, thus reducing the patient burden.