BACKGROUND: As RNA is labile, we investigated whether circulating RNA in human plasma may be present in a particle-associated form. METHODS: Blood was collected from 27 healthy individuals and 16 hepatocellular carcinoma (HCC) patients. The plasma from each individual was processed by two means: filtration through filters with different pore sizes (from 5 microm to 0.22 microm) and ultracentrifugation. We assessed plasma RNA content by a real-time quantitative reverse transcription-PCR assay for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) transcripts and plasma DNA by a real-time quantitative PCR assay for the beta-globin gene. RESULTS: The plasma GAPDH mRNA concentrations in the healthy individuals were significantly different in every pair of these filter sizes (P <0.05 for each pair). Overall, the plasma GAPDH mRNA concentration was higher by a median of 15-fold (interquartile range, 10- to 24-fold) in the paired unfiltered sample than in the sample filtered through a 0.22 microm filter. In contrast, no significant difference was seen in beta-globin DNA concentrations among different pore-size-filtered plasma samples (P = 0.455). Similarly, a significant difference was observed for RNA, but not DNA, between unfiltered plasma and ultracentrifuged plasma (P <0.05). No significant difference in GAPDH mRNA concentrations was seen between the 0.22-microm-filtered plasma samples and the ultracentrifuged plasma samples (P >0.05). In HCC patients, filtration with a 0.22 microm filter produced a median 9.3-fold (interquartile range, 6.9- to 311-fold) reduction in GAPDH mRNA concentration in plasma. Plasma GAPDH mRNA concentrations in HCC patients were significantly higher than those in healthy individuals, both with or without filtration (P <0.0 5 for filtered plasma samples; P <0.005 for unfiltered plasma samples). CONCLUSIONS: A substantial proportion of plasma mRNA species is particle-associated. In HCC patients, both circulating particle- and non-particle-associated plasma RNA are increased.
BACKGROUND: As RNA is labile, we investigated whether circulating RNA in human plasma may be present in a particle-associated form. METHODS: Blood was collected from 27 healthy individuals and 16 hepatocellular carcinoma (HCC) patients. The plasma from each individual was processed by two means: filtration through filters with different pore sizes (from 5 microm to 0.22 microm) and ultracentrifugation. We assessed plasma RNA content by a real-time quantitative reverse transcription-PCR assay for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) transcripts and plasma DNA by a real-time quantitative PCR assay for the beta-globin gene. RESULTS: The plasma GAPDH mRNA concentrations in the healthy individuals were significantly different in every pair of these filter sizes (P <0.05 for each pair). Overall, the plasma GAPDH mRNA concentration was higher by a median of 15-fold (interquartile range, 10- to 24-fold) in the paired unfiltered sample than in the sample filtered through a 0.22 microm filter. In contrast, no significant difference was seen in beta-globin DNA concentrations among different pore-size-filtered plasma samples (P = 0.455). Similarly, a significant difference was observed for RNA, but not DNA, between unfiltered plasma and ultracentrifuged plasma (P <0.05). No significant difference in GAPDH mRNA concentrations was seen between the 0.22-microm-filtered plasma samples and the ultracentrifuged plasma samples (P >0.05). In HCC patients, filtration with a 0.22 microm filter produced a median 9.3-fold (interquartile range, 6.9- to 311-fold) reduction in GAPDH mRNA concentration in plasma. Plasma GAPDH mRNA concentrations in HCC patients were significantly higher than those in healthy individuals, both with or without filtration (P <0.0 5 for filtered plasma samples; P <0.005 for unfiltered plasma samples). CONCLUSIONS: A substantial proportion of plasma mRNA species is particle-associated. In HCC patients, both circulating particle- and non-particle-associated plasma RNA are increased.
Authors: Stephen S C Chim; Yu K Tong; Rossa W K Chiu; Tze K Lau; Tse N Leung; Lisa Y S Chan; Cees B M Oudejans; Chunming Ding; Y M Dennis Lo Journal: Proc Natl Acad Sci U S A Date: 2005-10-03 Impact factor: 11.205
Authors: Enders K O Ng; Nancy B Y Tsui; Tze K Lau; Tse N Leung; Rossa W K Chiu; Nirmal S Panesar; Lydia C W Lit; Kam-Wing Chan; Y M Dennis Lo Journal: Proc Natl Acad Sci U S A Date: 2003-03-18 Impact factor: 11.205
Authors: Aaron F Orozco; Carolina J Jorgez; Cassandra Horne; Deborah A Marquez-Do; Matthew R Chapman; John R Rodgers; Farideh Z Bischoff; Dorothy E Lewis Journal: Am J Pathol Date: 2008-10-30 Impact factor: 4.307
Authors: José Miguel García; Vanesa García; Cristina Peña; Gemma Domínguez; Javier Silva; Raquel Diaz; Pablo Espinosa; Maria Jesús Citores; Manuel Collado; Félix Bonilla Journal: RNA Date: 2008-05-02 Impact factor: 4.942