Nuclear export of circular RNA

Circular RNAs (circRNAs), which are increasingly being implicated in a variety of functions in normal and cancerous cells1-5, are formed by back-splicing of precursor mRNAs in the nucleus6-10. circRNAs are predominantly localized in the cytoplasm, indicating that they must be exported from the nucleus. Here we identify a pathway that is specific for the nuclear export of circular RNA. This pathway requires Ran-GTP, exportin-2 and IGF2BP1. Enhancing the nuclear Ran-GTP gradient by depletion or chemical inhibition of the major protein exporter CRM1 selectively increases the nuclear export of circRNAs, while reducing the nuclear Ran-GTP gradient selectively blocks circRNA export. Depletion or knockout of exportin-2 specifically inhibits nuclear export of circRNA. Analysis of nuclear circRNA-binding proteins reveals that interaction between IGF2BP1 and circRNA is enhanced by Ran-GTP. The formation of circRNA export complexes in the nucleus is promoted by Ran-GTP through its interactions with exportin-2, circRNA and IGF2BP1. Our findings demonstrate that adaptors such as IGF2BP1 that bind directly to circular RNAs recruit Ran-GTP and exportin-2 to export circRNAs in a mechanism that is analogous to protein export, rather than mRNA export.

Multivariable model of postoperative delirium in cardiac surgery patients: proteomic and demographic contributions

Background

Delirium following cardiac surgery is common, morbid, and costly, but may be prevented with risk stratification and targeted intervention. Preoperative protein signatures may identify patients at increased risk for worse postoperative outcomes, including delirium. In this study, we aimed to identify plasma protein biomarkers and develop a predictive model for postoperative delirium in older patients undergoing cardiac surgery, while also uncovering possible pathophysiological mechanisms.

Methods

SOMAscan analysis of 1,305 proteins in the plasma from 57 older adults undergoing cardiac surgery requiring cardiopulmonary bypass was conducted to define delirium-specific protein signatures at baseline (PREOP) and postoperative day 2 (POD2). Selected proteins were validated in 115 patients using the ELLA multiplex immunoassay platform. Proteins were combined with clinical and demographic variables to build multivariable models that estimate the risk of postoperative delirium and bring light to the underlying pathophysiology.

Results

A total of 115 and 85 proteins from SOMAscan analyses were found altered in delirious patients at PREOP and POD2, respectively (p<0.05). Using four criteria including associations with surgery, delirium, and biological plausibility, 12 biomarker candidates (Tukey's fold change (|tFC|)>1.4, Benjamini-Hochberg (BH)-p<0.01) were selected for ELLA multiplex validation. Eight proteins were significantly altered at PREOP, and seven proteins at POD2 (p<0.05), in patients who developed postoperative delirium compared to non-delirious patients. Statistical analyses of model fit resulted in the selection of a combination of age, sex, and three proteins (angiopoietin-2 (ANGPT2); C-C motif chemokine 5 (CCL5); and metalloproteinase inhibitor 1 (TIMP1); AUC=0.829) as the best performing predictive model for delirium at PREOP. The delirium-associated proteins identified as biomarker candidates are involved with inflammation, glial dysfunction, vascularization, and hemostasis, highlighting the multifactorial pathophysiology of delirium.

Conclusion

Our study proposes a model of postoperative delirium that includes a combination of older age, female sex, and altered levels of three proteins. Our results support the identification of patients at higher risk of developing postoperative delirium after cardiac surgery and provide insights on the underlying pathophysiology. ClinicalTrials.gov ( NCT02546765 ).

Safety of Intranasal Insulin in Type 2 Diabetes on Systemic Insulin: A Double-Blinded Placebo-Controlled Sub-Study of Memaid Trial

AIMS

To determine safety of intranasal insulin (INI) in MemAID trial participants with diabetes treated with systemic insulins.

MATERIALS AND METHODS

This randomized, double-blinded trial consisted of 24-week INI or placebo treatment once daily and 24-week follow-up. Safety outcomes were: 1) Short-term effects on glycemic variability, hypoglycemic episodes on continuous glucose monitoring (CGM) at baseline and on-treatment. 2) Long-term effects on glucose metabolism and weight on INI/placebo treatment and post-treatment follow-up. Of 86 screened subjects, 14 were randomized, 9 (5 INI, 4 Placebo) completed CGM at baseline and on-treatment, and 5 (2 INI, 3 Placebo) completed treatment and follow-up.

RESULTS

INI was safe and was not associated with serious adverse events, hypoglycemic episodes or weight gain. INI administration did not acutely affect capillary glucose. Glycemic variability on CGM decreased with INI, compared to baseline. On INI treatment, there was a long-term trend toward lower HbA1c, plasma glucose and insulin. No interactions with subcutaneous insulins were observed.

CONCLUSIONS

INI is safe in older people with diabetes treated with systemic insulins, and it is not associated with adverse events, hypoglycemia or weight gain. Future studies are needed to determine whether INI administration can reduce glycemic variability, improve insulin sensitivity and thus potentially lessen diabetes burden in this population.

Gingival crevicular fluid proteomes in health, gingivitis and chronic periodontitis

OBJECTIVE

The aim of this study was to compare the proteome composition of gingival crevicular fluid obtained from healthy periodontium, gingivitis and chronic periodontitis affected sites.

BACKGROUND

Owing to its site-specific nature, gingival crevicular fluid is ideal for studying biological processes that occur during periodontal health and disease progression. However, few studies have been conducted into the gingival crevicular fluid proteome due to the small volumes obtained.

METHODS

Fifteen males were chosen for each of three different groups, healthy periodontium, gingivitis and chronic periodontitis. They were categorized based on clinical measurements including probing depth, bleeding on probing, plaque index, radiographic bone level, modified gingival index and smoking status. Gingival crevicular fluid was collected from each patient, pooled into healthy, gingivitis and chronic periodontitis groups and their proteome analyzed by gel electrophoresis and liquid chromatography electrospray ionization ion trap tandem mass spectrometry.

RESULTS

One hundred and twenty-one proteins in total were identified, and two-thirds of these were identified in all three conditions. Forty-two proteins were considered to have changed in abundance. Of note, cystatin B and cystatin S decreased in abundance from health to gingivitis and further in chronic periodontitis. Complement proteins demonstrated an increase from health to gingivitis followed by a decrease in chronic periodontitis. Immunoglobulins, keratin proteins, fibronectin, lactotransferrin precursor, 14-3-3 protein zeta/delta, neutrophil defensin 3 and alpha-actinin exhibited fluctuations in levels.

CONCLUSION

The gingival crevicular fluid proteome in each clinical condition was different and its analysis may assist us in understanding periodontal pathogenesis.

Mass spectrometric analysis of gingival crevicular fluid biomarkers can predict periodontal disease progression

BACKGROUND AND OBJECTIVE

Gingival crevicular fluid has been suggested as a possible source of biomarkers for periodontal disease progression. This paper describes a technique for the analysis of gingival crevicular fluid from individual sites using mass spectrometry. It explores the novel use of mass spectrometry to examine the relationship between the relative amounts of proteins and peptides in gingival crevicular fluid and their relationship with clinical indices and periodontal attachment loss in periodontal maintenance patients. The aim of this paper was to assess whether the mass spectrometric analysis of gingival crevicular fluid may allow for the site-specific prediction of periodontal disease progression.

MATERIAL AND METHODS

Forty-one periodontal maintenance subjects were followed over 12 mo, with clinical measurements taken at baseline and every 3 mo thereafter. Gingival crevicular fluid was collected from subjects at each visit and was analysed using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. Samples were classified based upon pocket depth, modified gingival index (MGI), plaque index and attachment loss, and were analysed within these groups. A genetic algorithm was used to create a model based on pattern analysis to predict sites undergoing attachment loss.

RESULTS

Three hundred and eighty-five gingival crevicular fluid samples were analysed. Twenty-five sites under observation in 14 patients exhibited attachment loss of > 2 mm over the 12-mo period. The clinical indices pocket depth, MGI, plaque levels and bleeding on probing served as poor discriminators of gingival crevicular fluid mass spectra. Models generated from the gingival crevicular fluid mass spectra could predict attachment loss at a site with a high specificity (97% recognition capability and 67% cross-validation).

CONCLUSIONS

Gingival crevicular fluid mass spectra could be used to predict sites with attachment loss. The use of algorithm-generated models based on gingival crevicular fluid mass spectra may provide utility in the diagnosis of periodontal disease.

Treadmill exercise testing in an epidemiologic study of elderly subjects

We sought to characterize the physical performance of older subjects in a community-based study of aging and fitness and to establish norms of oxygen consumption during exercise in this group. A community-based census identified 3057 age-eligible individuals of whom 2092 individuals (68.4%) agreed to participate in the overall study. Of these, 1101 subjects between 55 and 94 years of age who were free of known heart disease and able to perform treadmill exercise were tested using the Cornell protocol. Of these 1101 subjects, 73.8% of women and 89.5% of men (p < .001) exceeded what was considered a minimal threshold workload [i.e., > or =2 min of exercise and a respiratory exchange ratio (RER) > or = 1.00]. Moreover, 32.9% of women and 52.7% of men achieved a RER > or = 1.10 and were considered to have achieved maximal exercise. For all subjects who exceeded the minimal exercise workload, the mean exercise duration was 10.0 +/- 4.0 min for women and 13.2 +/- 4.6 min for men. Peak VO2/kg x min(-1) decreased linearly with age for both women (y = 38.33 - 0.27 x age + 1.12 H) and men (y = 41.78 - 0.26 x age + 12.65 H - 0.15 H x age), (p < .001 for sex difference), where H is defined as presence (=1) or absence (=0) of a disease condition. However, this sex-related difference disappeared when VO2/kg x min(-1) was adjusted for lean body mass. Thus, from a community-based sample of older persons, we have provided data (by 5-year age groups) for rates of participation in treadmill exercise testing and the success rate for achieving maximal exercise. Oxygen consumption and other exercise data are presented for older, healthy subjects as well as for those with various chronic diseases associated with aging (excluding those with cardiac or cerebrovascular disease). Exercise duration, peak VO2/kg x min(-1) (normalized for total and lean body mass), and peak exercise heart rate declined with age. Most of the sex difference in peak VO2/kg x min(-1) could be explained by the greater percent of body fat in women.

Working-age persons with multiple sclerosis and access to disease-modifying medications

US residents can face serious financial barriers to obtaining prescription medications, including disease-modifying medications for multiple sclerosis (MS). We conducted 30-min telephone surveys with 983 persons with MS nationwide, 21—64 years old, to explore how financial and health insurance concerns affect access to services including MS drugs. Almost everyone (96.3%) had some health insurance. Multivariable logistic regression analyses accounted for demographic, disease and insurance characteristics. Only 10.8% of those <40 years old had never received disease-modifying medications, compared with 41.1% of persons aged 60—64. Among the uninsured, 36.8% reported having never taken these medications, compared with 21.2% of persons with health insurance. Adjusted odds ratio (95% CI) of using these drugs in prior 12 months among the uninsured (compared with insured persons) was 0.28 (0.08, 0.95). Just over 16% of persons with public health plans reported that their insurer initially denied coverage for MS medication. When asked about MS medications in general, 22.3% reported having not filled prescriptions, skipping doses or splitting pills because of cost concerns; 22.4% worried `a lot' about getting MS medications when they needed them. Substantial fractions of persons with MS confront financial and health plan-related barriers to obtaining MS drugs. Multiple Sclerosis 2008; 14: 112—122. http://msj.sagepub.com

Amnestic disturbance and posttraumatic stress disorder in the aftermath of a chemical release

Neuropsychological assessments were performed on 70 patients referred after a Catacarb chemical release in a Northern California town. After appropriate exclusions, the 59 patients used in the final analysis were mostly White (66%), with 56% having some college level education. They were administered the: Wechsler Adult Intelligence Scale-Revised (WAIS-R), Memory Assessment Scale (MAS), Trails A and B, Stroop, Controlled Oral Word Association Test (COWAT), Fingertapping Test, Purdue Pegboard, Dynamometer, Rey 15-Item Test, Minnesota Multiphasic Personality Inventory-2 (MMPI-2), Brief Symptom Inventory (BSI), Beck Depression Index (BDI), Profile of Mood States (POMS), and Impact of Events Scale (IES) scales in addition to a health questionnaire and symptom checklist. Results indicate impaired scores on mnestic function and information processing when compared to Heaton's (1992) normative data, and the MAS norms (Williams, 1991). MMPI-2, BSI, BDI, POMS, and IES results indicate significant elevations on scales of depression, anxiety, anger, and posttraumatic stress disorder (PTSD) symptoms. The more brief tests of affect and mood appear sufficiently sensitive in measuring the dysphoric mood in group research studies. Clinical diagnoses using criteria from the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV; American Psychiatric Association, 1994) criteria indicate a prevalence of 54% PTSD and 64% Amnestic or Cognitive disturbance. New onset of dermatological, respiratory, visual, and gastrointestinal symptoms and illnesses are consistent with the chemical exposure, the PTSD may be in reaction to it, and Amnestic/Cognitive disturbance, from both an organic and functional etiology.