Meeting report: discussions and preliminary findings on extracellular RNA measurement methods from laboratories in the NIH Extracellular RNA Communication Consortium
Extracellular RNAs (exRNAs) have been identified in all tested biofluids and have been associated with a variety of extracellular vesicles, ribonucleoprotein complexes and lipoprotein complexes. Much of the interest in exRNAs lies in the fact that they may serve as signalling molecules between cells, their potential to serve as biomarkers for prediction and diagnosis of disease and the possibility that exRNAs or the extracellular particles that carry them might be used for therapeutic purposes. Among the most significant bottlenecks to progress in this field is the lack of robust and standardized methods for collection and processing of biofluids, separation of different types of exRNA‐containing particles and isolation and analysis of exRNAs. The Sample and Assay Standards Working Group of the Extracellular RNA Communication Consortium is a group of laboratories funded by the U.S. National Institutes of Health to develop such methods. In our first joint endeavour, we held a series of conference calls and in‐person meetings to survey the methods used among our members, placed them in the context of the current literature and used our findings to identify areas in which the identification of robust methodologies would promote rapid advancements in the exRNA field.
Integration of extracellular RNA profiling data using metadata, biomedical ontologies and Linked Data technologies
The large diversity and volume of extracellular RNA (exRNA) data that will form the basis of the exRNA Atlas generated by the Extracellular RNA Communication Consortium pose a substantial data integration challenge. We here present the strategy that is being implemented by the exRNA Data Management and Resource Repository, which employs metadata, biomedical ontologies and Linked Data technologies, such as Resource Description Framework to integrate a diverse set of exRNA profiles into an exRNA Atlas and enable integrative exRNA analysis. We focus on the following three specific data integration tasks: (a) selection of samples from a virtual biorepository for exRNA profiling and for inclusion in the exRNA Atlas; (b) retrieval of a data slice from the exRNA Atlas for integrative analysis and (c) interpretation of exRNA analysis results in the context of pathways and networks. As exRNA profiling gains wide adoption in the research community, we anticipate that the strategies discussed here will increasingly be required to enable data reuse and to facilitate integrative analysis of exRNA data.
Extracellular RNAs: development as biomarkers of human disease
Ten ongoing studies designed to test the possibility that extracellular RNAs may serve as biomarkers in human disease are described. These studies, funded by the NIH Common Fund Extracellular RNA Communication Program, examine diverse extracellular body fluids, including plasma, serum, urine and cerebrospinal fluid. The disorders studied include hepatic and gastric cancer, cardiovascular disease, chronic kidney disease, neurodegenerative disease, brain tumours, intracranial haemorrhage, multiple sclerosis and placental disorders. Progress to date and the plans for future studies are outlined.
ERβ Expression and Breast Cancer Risk Prediction for Women with Atypias
Abstract 2364: CD68+ immune cells show different infiltration patterns in tissue samples from women with no clinical breast disease and those who have benign breast disease
Abstract Introduction: The role of macrophages in the tumor microenvironment is of increasing interest for tumor progression and invasion. Here we investigated the difference in CD68+ cell density in tissue samples from women with Benign Breast Disease (BBD) and women with no clinical breast disease from the Komen Tissue Bank (KTB) at Indiana University. Method: Archived breast tissue samples from women with BBD and no clinical breast disease were obtained for this age-matched case-control study. BBD samples included cases [later got Breast Cancer (BC)] and controls (did not get BC). Samples were characterized via H&E stain for epithelial proliferation [normal (N), fibrocystic non-proliferative (NP), proliferative (P), or atypia (A)]. CD68+ cell density was obtained by digital image quantitation on a per lobule basis (Total CD68+ cells/mm2). Statistical analysis was performed with mixed effects regression. Results: Among 276 women (median age 53, range 35-79) comprising 92 age-matched triplets, 2508 lobules were evaluated [789 KTB, 839 BBD case, 880 BBD control]. 1407 (56%) lobules were normal and 1101 (44%) were fibrocystic {NP [613 (56%)], P [448 (41%)] and A [40 (4%)]}. Out of 2508 lobules analyzed, 2362 (94%) had CD68+ cells, while 146 (6%) showed zero CD68+ cells [19 (2%) BBD cases, 20 (2%) BBD controls, 107 (14%) KTB, p<0.0001]. KTB samples showed significantly lower (p<0.0001) CD68+ density (median 136 cells/mm2) as compared to BBD cases (median 313 cells/mm2) and BBD controls (median 299 cells/mm2). (See Table) For each lobule type, KTB samples had lower CD68+ density compared with the same lobule type in BBD samples (p<0.0001). Conclusion: CD68+ cells are more frequent in breast lobules from women with BBD compared to normal donors. This finding in premalignant breast tissues is consistent with inflammation as a driver of tumorigenesis. BBD case (n = 92 patients)BBD control (n = 92 patients)KTB(n = 92 patients)n lobulesMedian (IQR)n lobulesMedian (IQR)n lobulesMedian (IQR)Overall839313 (165 - 538)880299 (164 - 527)789136 (55 - 272)By Lobule TypeNormal344310 (177 - 557)434331 (177 - 567)629128 (55 - 255)All non-normal/fibrocystic lobules combined495314 (157 - 527)446274 (152 - 478)160159 (58 - 393)Fibrocystic non-proliferative231319 (153 - 543)263274 (140 - 496)119163 (71 - 359)Fibrocystic proliferative246295 (153 - 496)169277 (153 - 478)33128 (30 - 385)Atypia18484 (313 - 739)14260 (223 - 375)8216 (0 - 493)IQR - Interquartile range (25th percentile - 75th percentile) Citation Format: Muhammad A. Arshad, Daniel W. Visscher, Tanya L. Hoskin, Rushin D. Brahmbhatt, Alvaro Pena Jimenez, Melody L. Stallings Mann, Erin E. Miller, Linda M. Murphy, Jodi M. Carter, Stacey J. Winham, Keith L. Knutson, Derek C. Radisky, Amy C. Degnim. CD68+ immune cells show different infiltration patterns in tissue samples from women with no clinical breast disease and those who have benign breast disease. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2364. doi:10.1158/1538-7445.AM2015-2364
Nocturnal Glucose Metabolism in Type 1 Diabetes: A Study Comparing Single Versus Dual Tracer Approaches
Background: Understanding the effect size, variability, and underlying physiology of the dawn phenomenon is important for next-generation closed-loop control algorithms for type 1 diabetes (T1D). Subjects and Methods: We used an iterative protocol design to study 16 subjects with T1D on individualized insulin pump therapy for two successive nights. Endogenous glucose production (EGP) rates at 3 a.m. and 7 a.m. were measured with [6,6- 2 H 2 ]glucose as a single tracer, infused from midnight to 7 a.m. in all subjects. To explore possibility of tracer recycling due to prolonged [6,6- 2 H 2 ]glucose infusion, which was highly probable after preplanned interim data analyses, we infused a second tracer, [6- 3 H]glucose, from 4 a.m. to 7 a.m. in the last seven subjects to measure EGP at 7 a.m. Results: Cortisol concentrations increased during both nights, but changes in glucagon and insulin concentration were inconsistent. Although the plasma glucose concentrations rose from midnight to 7 a.m. during both nights, EGP measured with [6,6- 2 H 2 ]glucose between 3 a.m. and 7 a.m. did not differ during Night 1 but fell in Night 2. However, EGP measured with [6- 3 H]glucose at 7 a.m. was higher than that measured with [6,6- 2 H 2 ]glucose during both nights, thereby suggesting tracer recycling probably underestimating EGP calculated at 7 a.m. with [6,6- 2 H 2 ]glucose. Likewise, EGP was higher at 7 a.m. with [6- 3 H]glucose than at 3 a.m. with [6,6- 2 H 2 ]glucose during both nights. Conclusions: The data demonstrate a consistent overnight rise in glucose concentrations through increased EGP, mediated likely by rising cortisol concentrations. The observations with the dual tracer approach imply significant tracer recycling leading to underestimation of EGP measured by longer-duration tracer infusion.
Oral Contraceptive Use, Muscle Sympathetic Nerve Activity, and Systemic Hemodynamics in Young Women
Endogenous female sex hormones influence muscle sympathetic nerve activity (MSNA), a regulator of arterial blood pressure and important factor in hypertension development. Although ≈80% of American women report using hormonal contraceptives sometime during their life, the influence of combined oral contraceptives (OCs) on MSNA and systemic hemodynamics remains equivocal. The goal of this study was to determine whether women taking OCs have altered MSNA and hemodynamics (cardiac output and total peripheral resistance) at rest during the placebo phase of OC use compared with women with natural menstrual cycles during the early follicular phase. We retrospectively analyzed data from studies in which healthy, premenopausal women (aged 18–35 years) participated. We collected MSNA values at rest and hemodynamic measurements in women taking OCs (n=53; 25±4 years) and women with natural menstrual cycles (n=74; 25±4 years). Blood pressure was higher in women taking OCs versus those with natural menstrual cycles (mean arterial pressure, 89±1 versus 85±1 mm Hg, respectively; P =0.01), although MSNA was similar in both groups (MSNA burst incidence, 16±1 versus 18±1 bursts/100 heartbeats, respectively; P =0.19). In a subset of women in which detailed hemodynamic data were available, those taking OCs (n=33) had similar cardiac output (4.9±0.2 versus 4.7±0.2 L/min, respectively; P =0.47) and total peripheral resistance (19.2±0.8 versus 20.0±0.9 U, respectively; P =0.51) as women with natural menstrual cycles (n=22). In conclusion, women taking OCs have higher resting blood pressure and similar MSNA and hemodynamics during the placebo phase of OC use when compared with naturally menstruating women in the early follicular phase.