Abstract WP401: Burden of Intracranial Hemorrhage in Patients With Reversible Cerebral Vasoconstriction Syndrome

Introduction: Reversible Cerebral Vasoconstriction Syndrome (RCVS) is described as reversible constriction of cerebral arteries, presenting with severe headaches and associated with hemorrhagic or ischemic strokes. There is a dearth of the literature on demographics and risk factors associated with intracranial hemorrhage (ICH) in patients with RCVS in the US.

Methods: All patients with a primary or secondary diagnosis of RCVS in 2016 Nationwide Readmission Database (NRD) using ICD-10 code I67.841 after excluding cerebral angiitis (N=57). Unique patients were included using a unique patient identifier. Weighted discharges were used to generate national estimates. ICH was defined as both intraparenchymal and subarachnoid hemorrhage. A multivariable logistic model was used to identify ICH predictors.

Results: Among total 1,152 RCVS patients, 25.7% (296) patients developed ICH. Patients with ICH mean age was (years) (Mean±SE) 47.8 ±1.2 vs. 47.0±1.1 (P=0.62), female 85.4% vs. 78.0% (P=0.06), longer inpatient LOS 12.1±0.9 vs. 6.4±0.5 days (P<0.0001) and higher inpatient cost 42,638±4,451 vs. 18,199±1,117 (P=0.018). After multivariable analysis, two independent predictors of ICH were identified: increasing age (OR 1.02, 95% CI: 1.01-1.04, P=0.042) and female gender (OR 2.37, 95%CI: 1.25-4.50, P=0.009). Patients with ICH were at a greater risk of cerebral edema (OR 13.25, 95% CI: 5.10-34.43, P<0.0001) (Figure). Among disposition, 63.2% of patients with ICH were discharged home requiring no assistance and no mortality was observed.

Conclusion: This nationally representative sample suggests that increasing age and female gender were independent predictors of ICH. There is no difference in comorbidities including migraine contrary to prior literature, modifiable lifestyle risk factors and pregnancy in this cohort. Excellent outcome was observed as the majority of patients were discharged home. Higher LOS and cost were reported in ICH cohort.

Abstract TP139: Utilization and Outcomes of Extracranial-Intracranial Bypass Surgery in Adult Moyamoya Population

Introduction: The Extracranial-Intracranial bypass (EC-IC) surgery is performed to restore blood flow to the brain and prevent both hemorrhagic and ischemic strokes in Moyamoya disease (MMD) patients. There is a lack of contemporary data regarding EC-IC utilization, racial disparities, related mortality, and disability in the US.

Method: Using ICD 9-CM codes 437.5 and 39.28, MMD and EC-IC procedures were extracted from National Inpatient Sample 2005-2015. The weighted discharge was used to generate national estimates. Predictors of revascularization utilization were evaluated using multivariable logistic regression analysis to avoid confounding effect. Disability was defined as non-home discharges, after excluding mortality.

Results: Of total 24,484 admissions for MMD, 3,965 (16.2%) underwent revascularization. The mean age of revascularization patients was (SE) ~42 (0.52) years and F: M ratio of 3:1. After multivariable logistic model analysis, higher utilization rates were found in 40-59 year age group (48.3%, OR:1.29; P=0.02), who had ischemic strokes (9.2%, OR:1.38; P=0.03), and conventional cerebral angiography (30.2%, OR:1.80; P=0.001). Lower utilization rates were found in African Americans (14.9%, OR: 0.66; P=0.004), Hispanics (5.7%, OR: 0.60; P=0.03), Medicare recipients (13.6%, OR: 0.55; P=0.009), Northeast (11.5%, OR: 0.47; P= 0.003), Midwest (22.7%, OR: 0.55; P= 0.02), and South (24.8%, OR: 0.46; P=0.0002) compared to the West region. There is no utilization difference in gender female (72.4%, OR: 0.89; P=0.36). After EC-IC surgery, 79% were discharged home, 21% discharged to assistive facilities, and 0.6% died. After adjusting for hospital characteristics and associated comorbidities, lower disability (OR: 0.75; P=0.04) and the mortality rate was reported (OR: 0.80; P=0.71) among revascularization.

Conclusions: This nationally representative date within the US suggests that though there is no gender disparity in utilization of EC-IC bypass surgery, there is a significant racial and regional disparity in the utilization of the procedure. Patients undergoing revascularization had better functional outcomes. Further research is needed to identify potential predictors for underutilization in these cohorts.

Abstract WP207: Current Incidence, Epidemiological and Clinical Characteristics of Reversible Cerebral Vasoconstriction in the United States

Background: There is a paucity of contemporary data on incidence, epidemiological and clinical characteristics of reversible cerebral vasoconstriction syndrome (RCVS) in the United States. This study aimed to address these gaps in knowledge.

Method: All patients with a primary and secondary diagnosis of RCVS were identified from the 2016 National Readmissions Database (n=1,152) using International Classification of Disease-10 code I67.841. Unique patients were defined using the NRD’s unique patient identifier. Overall and sex-specific incidences of RCVS were computed by combining RCVS counts with the 2016 US census population data. RCVS comorbidities, complications and outcome were presented using descriptive statistics.

Result: The overall incidence of RCVS per million population (SE) was 4.62 (0.14) but the incidence in women 7.20 (0.24) was nearly four times that of men 1.91(0.13). Mean age (SE) was 47.2(0.9) but up to 87% of patients were < 65 years. Most common comorbidities seen in these patients were hypertension 51.7%, diabetes 19.3%, hyperlipidemia 25.4%, inflammatory disorders 20.7%, pregnancy 7.6%, postpartum 8.6%, and preeclampsia-eclampsia conditions 4.4%. Illicit drug abuse was nicotine 24.2%, cannabis 7.7%, alcohol 3.1% and cocaine 1.1%. A cerebral angiogram was documented in 25.1% of cases, and spinal tap in 16.3%. Most common associated complications included subarachnoid hemorrhage 21.3%, migraine 18.6%, ischemic stroke 14%, intracerebral hemorrhage 8.6%, epilepsy 9.3%, brain edema 7%, PRES 6.7%, and thunderclap headache 5.9%. Majority of patients were admitted to urban 88% and larger bedside hospital 60%. Majority of patients have private insurance 46% followed by Medicaid 24% and Medicare 23%. Average inpatient cost ($) was 25,135 ± 1,690.9 and length of Stay (Days) was 8.0 ± 0.4. Excellent outcomes were reported including 71% discharge to home, 14% of patients were discharged to a facility and in-hospital mortality was rare (0.4%).

Conclusion: RCVS is still rare in the US but the current incidence in women is almost four times that of men. Subarachnoid hemorrhage appears to be the most common documented comorbidity but in-hospital mortality is rare.

Abstract WP374: 30 Days Unplanned Readmission (30-DR) in Cerebral Vein Thrombosis: US National Retrospective Analysis

Introduction: Thrombosis of the cerebral veins and/or dural sinuses (CVST) results in 0.5% to 1% of all strokes. CVST has a lower mortality rate compared to arterial stroke; however it predisposes to certain complications, which lead to frequent hospital readmissions.

Objective: To study the readmission rate, reasons for readmissions and predictors of intracranial hemorrhage (ICH).

Method: Using the Nationwide Readmission Database (NRD) from 2013 -2014 patients with a primary discharge diagnosis of CVST (ICD 9 CM code: 437.6, 325, and 671.5) were identified. Their post-hospitalization course was tracked using the variable “NRD_visitlink,” and the time between re-admissions was calculated by subtracting the variable “NRD_DaysToEvent”. SAS 9.4 was used for data analysis with categorical and continuous variables tested using the Rao Scott Chi-square test and Student’s t-test, respectively. Multivariate logistic regression models were used for categorical dependent variable.

Result: A total of 3,611 (weighted) Index discharges of CVST were identified. After excluding elective readmissions, 11.32%, 17.04% and 21.81% were the observed readmission rates at 30, 90 and 180 day-follow-up periods respectively. The common causes of 30-day readmission (30-DR) were complications of the puerperium (8.76%), ICH (6.13%), migraine (4.23%), ischemic stroke (2.86%), sepsis (2.30%) and hypertensive complications (1.83%). Epilepsy related readmissions were observed only in the 90-day (1.95%) and 180-day (2.51%) follow up periods. The mean 30-DR cost was lower vs. Index admission (Mean ± SE $ 12,439±1139 vs. $ 16314±652; P value <0.0001) while the length of stay (LOS) during readmission was also lower compared to Index LOS (Mean ± SE 5.0±0.4 vs. 6.4±0.2 ;< 0.0001). After adjusting age and gender, multivariate predictors of increase risk of ICH readmission were hypertension (OR 4.79 CL 1.38-16.59; P=0.0068), primary hypercoagulable state (OR 3.34, CL 1.12-9.99; P=0.0306), meningitis (OR 17.77 CL 2.51-125.96, P=0.0041) and chronic kidney disease (OR 3.80CL 1.04-13.85, P=0.0434).

Conclusion: Puerperal complications, ICH, epilepsy and sepsis are the most common complications prompting re-hospitalization in patients diagnosed with CVST.

Comparison of angioplasty and bypass surgery for critical limb ischaemia in patients with infrapopliteal peripheral artery disease

BACKGROUND

Both infrapopliteal (IP) bypass surgery and percutaneous transluminal angioplasty have been shown to be effective in patients with critical limb ischaemia (CLI). The most appropriate method of revascularization has yet to be established, as no randomized trials have been reported. The aim of this study was to compare the outcomes of patients with similar characteristics treated using either revascularization method.

METHODS

Consecutive patients undergoing IP bypass and IP angioplasty for CLI (Rutherford 4-6) at a single institution were compared following propensity score matching. The study endpoints were primary, assisted primary and secondary patency, and amputation-free survival at 12 months, calculated by Kaplan-Meier analysis.

RESULTS

Some 279 limbs in 243 patients were included in the study. The two groups differed significantly with respect to the incidence of diabetes (P = 0·024), estimated glomerular filtration rate (P = 0·006), total lesion length (P < 0·001) and Rutherford classification (P = 0·008). These factors were used to construct the propensity score model, which yielded a matched cohort of 125 legs in each group. Primary patency (54·4 versus 51·4 per cent; P = 0·014), assisted primary patency (77·5 versus 62·7 per cent; P = 0·003), secondary patency (84·4 versus 65·8 per cent; P < 0·001) and amputation-free survival (78·7 versus 74·1 per cent; P = 0·043) were significantly better after bypass than angioplasty. However, limb salvage was similar (90·4 versus 94·2 per cent; P = 0·161), and overall complications (36·0 versus 21·6 per cent; P = 0·041) as well as length of hospital stay (18(4-134) versus 5(0-110); P = 0·001) were worse in the surgical bypass group.

CONCLUSION

There was no difference in limb salvage rates, but patency and amputation-free survival rates were better 1 year after bypass surgery.

Atherosclerotic Plaque Analysis: A Pilot Study to Assess a Novel Tool to Predict Outcome Following Lower Limb Endovascular Intervention

INTRODUCTION

Atherosclerotic plaque analysis using computed tomography angiography (CTA) has been found to be accurate and reproducible in the coronary and carotid arteries. The aim of our study was to assess the utility of this technique in predicting outcome following lower limb endovascular interventions.

METHODS

Pre-procedural CTA was retrospectively analysed in 50 patients who had undergone femoropopliteal (F-P) angioplasty (and/or stenting). Plaque analysis was performed using TeraRecon workstation by two observers blinded to the long-term outcome. Using the Hounsfield units (HU) scale atherosclerotic plaque composition was subdivided into volumes of soft (-100-100 HU) fibrocalcific (101-300 HU) or calcified (300-1000 HU) components. The relationship between plaque composition, clinical and procedural variables, and the study end points (vessel patency, binary restenosis rate, and Amputation-Free Survival [AFS]) were assessed using multivariate analysis.

RESULTS

The technical success rate of the endovascular procedure was 98%, with 48% of patients receiving F-P stents. The AFS was 90%, primary patency 84%, assisted primary patency 88%, and binary restenosis 44% all at 1 year. A significantly greater total volume of calcified plaque (1.1 [.01-3.2] cm(3) vs. .11 [0-1.86] cm(3), p < .001) was found in patients developing restenosis (>50%) compared with those who did not. Patients with a calcified plaque volume greater than 1.1 cm(3) had a significantly worse AFS than those with a volume less than 1.1 cm(3) (p = .0038). Multivariate analysis showed that the percentage calcified plaque (p = .003, HR 11.4, 95% CI 1.45-37.29) was an independent predictor of binary restenosis at 12 months, and that absolute volume of calcified plaque (p = .001, HR 3.56, 95% CI 1.64-7.7) was independently associated with AFS.

CONCLUSIONS

The burden of calcified plaque, but not soft or fibrocalcific plaque is related to restenosis, reintervention, and AFS. Computed tomography plaque analysis may form an important non-invasive tool for risk stratification in patients undergoing F-P endovascular procedures.

Hybrid revascularization of complex multilevel disease: a paradigm shift in critical limb ischemia treatment

Critical limb ischemia frequently occurs on a background of extensive co-morbidities and carries a poor prognosis which requires urgent management. Disease severity and patient comorbidity influence the initial choice of management which according to traditional paradigms, is a choice between open or endovascular repair. Over the last decade hybrid intervention, which is the planned combined use of both open and endovascular techniques, has increasingly been used to tackle multilevel disease. In this review we look at the techniques and results of hybrid surgery. This technique is ideal for multilevel lesions, as it is minimally invasive, allows prompt limb revascularization as opposed to the delays inherent in staged procedures and it appears to be more convenient to patients. It also leads to reduced length of hospital stay and reduces overall cost. Most importantly it offers an alternative to open revascularization in medically high risk patients. The success and popularity of hybrid interventions has been underpinned by advances in stent and balloon technology and the advent of the hybrid operating theatre which has allowed multiple techniques to be used simultaneously. Iliac angioplasty and stenting is now the first line of treatment for TASC C/D iliac lesions with good technical success and long-term patency. In patients who also have common femoral disease, endarterectomy can be combined with iliac stenting and this has now almost replaced open bypass. Most series for a variety of hybrid procedures report good limb salvage rates, with morbidity and mortality data considered equal to or better than open bypass procedures. Careful patient selection and detailed preoperative planning are essential to achieve these excellent results. Studies have reported on prospective series or retrospective analysis for various hybrid techniques, including non randomized trials comparing hybrid and open surgical treatment. Ideally, a randomized controlled trial comparing open and hybrid treatment is needed to minimize confounding variables.

Thyroid surgery as a 23-hour stay procedure

INTRODUCTION

The main barriers to short stay thyroidectomy are haemorrhage, bilateral recurrent laryngeal nerve palsy causing respiratory compromise and hypocalcaemia. This study assessed the safety and effectiveness of thyroidectomy as a 23-hour stay procedure.

METHODS

All patients undergoing total or completion thyroidectomy were prescribed calcium and vitamin D3 supplements following surgery. Retrospective analysis identified patients admitted for longer than 23 hours and any readmissions.

RESULTS

A total of 164 patients were admitted for 23-hour stay thyroid surgery over a 25-month period between 2008 and 2010. Four patients (2%) required admission for longer than 23 hours. No patients required emergency intervention for postoperative haemorrhage or airway compromise. Biochemical hypocalcaemia (despite calcium supplements) was detected in one patient when measured at the outpatient clinic two weeks following surgery. Twelve patients (7.3%) attended the accident and emergency department following discharge; four required admission for intravenous antibiotics for wound infection and one for biochemical hypocalcaemia.

CONCLUSIONS

This single centre UK experience demonstrates that thyroidectomy can be carried out both safely and effectively as a 23-hour stay procedure. Prophylactic prescription of calcium and vitamin D3 reduces hypocalcaemia, and thereby also prolonged admission and readmission due to hypocalcaemia. Supplements are an acceptable, cost effective method of reducing hypocalcaemia and shortening postoperative length of stay.

Convergent functional genomics of schizophrenia: from comprehensive understanding to genetic risk prediction

We have used a translational convergent functional genomics (CFG) approach to identify and prioritize genes involved in schizophrenia, by gene-level integration of genome-wide association study data with other genetic and gene expression studies in humans and animal models. Using this polyevidence scoring and pathway analyses, we identify top genes (DISC1, TCF4, MBP, MOBP, NCAM1, NRCAM, NDUFV2, RAB18, as well as ADCYAP1, BDNF, CNR1, COMT, DRD2, DTNBP1, GAD1, GRIA1, GRIN2B, HTR2A, NRG1, RELN, SNAP-25, TNIK), brain development, myelination, cell adhesion, glutamate receptor signaling, G-protein-coupled receptor signaling and cAMP-mediated signaling as key to pathophysiology and as targets for therapeutic intervention. Overall, the data are consistent with a model of disrupted connectivity in schizophrenia, resulting from the effects of neurodevelopmental environmental stress on a background of genetic vulnerability. In addition, we show how the top candidate genes identified by CFG can be used to generate a genetic risk prediction score (GRPS) to aid schizophrenia diagnostics, with predictive ability in independent cohorts. The GRPS also differentiates classic age of onset schizophrenia from early onset and late-onset disease. We also show, in three independent cohorts, two European American and one African American, increasing overlap, reproducibility and consistency of findings from single-nucleotide polymorphisms to genes, then genes prioritized by CFG, and ultimately at the level of biological pathways and mechanisms. Finally, we compared our top candidate genes for schizophrenia from this analysis with top candidate genes for bipolar disorder and anxiety disorders from previous CFG analyses conducted by us, as well as findings from the fields of autism and Alzheimer. Overall, our work maps the genomic and biological landscape for schizophrenia, providing leads towards a better understanding of illness, diagnostics and therapeutics. It also reveals the significant genetic overlap with other major psychiatric disorder domains, suggesting the need for improved nosology.

Pharmacokinetics of gatifloxacin in broiler chickens following intravenous and oral administration

1. The pharmacokinetics of gatifloxacin were investigated following intravenous and oral administration of a single dose at a rate of 10 mg/kg body weight in broiler chicks. 2. Drug concentration in plasma was determined using High Performance Liquid Chromatography with ultraviolet detection on samples collected at frequent intervals after drug administration. 3. Following intravenous administration, the drug was rapidly distributed (t(1/2α): 0·33 ± 0·008 h) and eliminated (t(1/2β): 3·62 ± 0·03 h; Cl(B): 0·48 ± 0·002 l/h/kg) from the body. 4. After oral administration, the drug was rapidly absorbed (C (max): 1·74 ± 0·024 µg/mL; T (max): 2 h) and slowly eliminated (t(1/2β): 3·81 ± 0·07 h) from the body. The apparent volume of distribution (V(d(area))), total body clearance (Cl(B)) and mean residence time (MRT) were 3·61 ± 0·04 l/kg, 0·66 ± 0·01 l/h/kg and 7·16 ± 0·08 h, respectively. The oral bioavailability of gatifloxacin was 72·96 ± 1·10 %. 5. Oral administration of gatifloxacin at 10 mg/kg is likely to be highly efficacious against susceptible bacteria in broiler chickens.

Case report. A novel approach to the management of a ruptured Type II endoleak following endovascular repair of an internal iliac artery aneurysm

Endovascular repair of isolated iliac artery aneurysms is an established safe and effective management option. Type II endoleak is a potential complication, but rarely results in significant morbidity or mortality. We report a case of a patient who presented with a ruptured internal iliac artery aneurysm secondary to a Type II endoleak. To our knowledge this and the following method of managing this have not been previously reported. Established methods of managing endoleaks, such as intravascular transfemoral embolisation and open or laparoscopic ligation, were not possible. Therefore, we resorted to a novel approach to this type of aneurysm and successfully performed a transcutaneous direct puncture and embolisation of the superior gluteal artery.

Convergent functional genomics of anxiety disorders: translational identification of genes, biomarkers, pathways and mechanisms

Anxiety disorders are prevalent and disabling yet understudied from a genetic standpoint, compared with other major psychiatric disorders such as bipolar disorder and schizophrenia. The fact that they are more common, diverse and perceived as embedded in normal life may explain this relative oversight. In addition, as for other psychiatric disorders, there are technical challenges related to the identification and validation of candidate genes and peripheral biomarkers. Human studies, particularly genetic ones, are susceptible to the issue of being underpowered, because of genetic heterogeneity, the effect of variable environmental exposure on gene expression, and difficulty of accrual of large, well phenotyped cohorts. Animal model gene expression studies, in a genetically homogeneous and experimentally tractable setting, can avoid artifacts and provide sensitivity of detection. Subsequent translational integration of the animal model datasets with human genetic and gene expression datasets can ensure cross-validatory power and specificity for illness. We have used a pharmacogenomic mouse model (involving treatments with an anxiogenic drug--yohimbine, and an anti-anxiety drug--diazepam) as a discovery engine for identification of anxiety candidate genes as well as potential blood biomarkers. Gene expression changes in key brain regions for anxiety (prefrontal cortex, amygdala and hippocampus) and blood were analyzed using a convergent functional genomics (CFG) approach, which integrates our new data with published human and animal model data, as a translational strategy of cross-matching and prioritizing findings. Our work identifies top candidate genes (such as FOS, GABBR1, NR4A2, DRD1, ADORA2A, QKI, RGS2, PTGDS, HSPA1B, DYNLL2, CCKBR and DBP), brain-blood biomarkers (such as FOS, QKI and HSPA1B), pathways (such as cAMP signaling) and mechanisms for anxiety disorders--notably signal transduction and reactivity to environment, with a prominent role for the hippocampus. Overall, this work complements our previous similar work (on bipolar mood disorders and schizophrenia) conducted over the last decade. It concludes our programmatic first pass mapping of the genomic landscape of the triad of major psychiatric disorder domains using CFG, and permitted us to uncover the significant genetic overlap between anxiety and these other major psychiatric disorders, notably the under-appreciated overlap with schizophrenia. PDE10A, TAC1 and other genes uncovered by our work provide a molecular basis for the frequently observed clinical co-morbidity and interdependence between anxiety and other major psychiatric disorders, and suggest schizo-anxiety as a possible new nosological domain.

Convergent functional genomic studies of ω-3 fatty acids in stress reactivity, bipolar disorder and alcoholism

Omega-3 fatty acids have been proposed as an adjuvant treatment option in psychiatric disorders. Given their other health benefits and their relative lack of toxicity, teratogenicity and side effects, they may be particularly useful in children and in females of child-bearing age, especially during pregnancy and postpartum. A comprehensive mechanistic understanding of their effects is needed. Here we report translational studies demonstrating the phenotypic normalization and gene expression effects of dietary omega-3 fatty acids, specifically docosahexaenoic acid (DHA), in a stress-reactive knockout mouse model of bipolar disorder and co-morbid alcoholism, using a bioinformatic convergent functional genomics approach integrating animal model and human data to prioritize disease-relevant genes. Additionally, to validate at a behavioral level the novel observed effects on decreasing alcohol consumption, we also tested the effects of DHA in an independent animal model, alcohol-preferring (P) rats, a well-established animal model of alcoholism. Our studies uncover sex differences, brain region-specific effects and blood biomarkers that may underpin the effects of DHA. Of note, DHA modulates some of the same genes targeted by current psychotropic medications, as well as increases myelin-related gene expression. Myelin-related gene expression decrease is a common, if nonspecific, denominator of neuropsychiatric disorders. In conclusion, our work supports the potential utility of omega-3 fatty acids, specifically DHA, for a spectrum of psychiatric disorders such as stress disorders, bipolar disorder, alcoholism and beyond.

Identification of blood biomarkers for psychosis using convergent functional genomics

There are to date no objective clinical laboratory blood tests for psychotic disease states. We provide proof of principle for a convergent functional genomics (CFG) approach to help identify and prioritize blood biomarkers for two key psychotic symptoms, one sensory (hallucinations) and one cognitive (delusions). We used gene expression profiling in whole blood samples from patients with schizophrenia and related disorders, with phenotypic information collected at the time of blood draw, then cross-matched the data with other human and animal model lines of evidence. Topping our list of candidate blood biomarkers for hallucinations, we have four genes decreased in expression in high hallucinations states (Fn1, Rhobtb3, Aldh1l1, Mpp3), and three genes increased in high hallucinations states (Arhgef9, Phlda1, S100a6). All of these genes have prior evidence of differential expression in schizophrenia patients. At the top of our list of candidate blood biomarkers for delusions, we have 15 genes decreased in expression in high delusions states (such as Drd2, Apoe, Scamp1, Fn1, Idh1, Aldh1l1), and 16 genes increased in high delusions states (such as Nrg1, Egr1, Pvalb, Dctn1, Nmt1, Tob2). Twenty-five of these genes have prior evidence of differential expression in schizophrenia patients. Predictive scores, based on panels of top candidate biomarkers, show good sensitivity and negative predictive value for detecting high psychosis states in the original cohort as well as in three additional cohorts. These results have implications for the development of objective laboratory tests to measure illness severity and response to treatment in devastating disorders such as schizophrenia.

Coming to grips with complex disorders: genetic risk prediction in bipolar disorder using panels of genes identified through convergent functional genomics

We previously proposed and provided proof of principle for the use of a complementary approach, convergent functional genomics (CFG), combining gene expression and genetic data, from human and animal model studies, as a way of mining the existing GWAS datasets for signals that are there already, but did not reach significance using a genetics-only approach [Le-Niculescu et al., 2009b]. CFG provides a fit-to-disease prioritization of genes that leads to generalizability in independent cohorts, and counterbalances the fit-to-cohort prioritization inherent in classic genetic-only approaches, which have been plagued by poor reproducibility across cohorts. We have now extended our previous work to include more datasets of GWAS, and more recent evidence from other lines of work. In essence our analysis is the most comprehensive integration of genetics and functional genomics to date in the field of bipolar disorder. Biological pathway analyses identified top canonical pathways, and epistatic interaction testing inside these pathways has identified genes that merit future follow-up as direct interactors (intra-pathway epistasis, INPEP). Moreover, we have put together a panel of best P-value single nucleotide polymorphisms (SNPs), based on the top candidate genes we identified. We have developed a genetic risk prediction score (GRPS) based on our panel, and demonstrate how in two independent test cohorts the GRPS differentiates between subjects with bipolar disorder and normal controls, in both European-American and African-American populations. Lastly, we describe a prototype of how such testing could be used to categorize disease risk in individuals and aid personalized medicine approaches, in psychiatry and beyond.

Convergent functional genomics of genome-wide association data for bipolar disorder: comprehensive identification of candidate genes, pathways and mechanisms

Given the mounting convergent evidence implicating many more genes in complex disorders such as bipolar disorder than the small number identified unambiguously by the first-generation Genome-Wide Association studies (GWAS) to date, there is a strong need for improvements in methodology. One strategy is to include in the next generation GWAS larger numbers of subjects, and/or to pool independent studies into meta-analyses. We propose and provide proof of principle for the use of a complementary approach, convergent functional genomics (CFG), as a way of mining the existing GWAS datasets for signals that are there already, but did not reach significance using a genetics-only approach. With the CFG approach, the integration of genetics with genomics, of human and animal model data, and of multiple independent lines of evidence converging on the same genes offers a way of extracting signal from noise and prioritizing candidates. In essence our analysis is the most comprehensive integration of genetics and functional genomics to date in the field of bipolar disorder, yielding a series of novel (such as Klf12, Aldh1a1, A2bp1, Ak3l1, Rorb, Rora) and previously known (such as Bdnf, Arntl, Gsk3b, Disc1, Nrg1, Htr2a) candidate genes, blood biomarkers, as well as a comprehensive identification of pathways and mechanisms. These become prime targets for hypothesis driven follow-up studies, new drug development and personalized medicine approaches.

Identifying blood biomarkers for mood disorders using convergent functional genomics

There are to date no objective clinical laboratory blood tests for mood disorders. The current reliance on patient self-report of symptom severity and on the clinicians' impression is a rate-limiting step in effective treatment and new drug development. We propose, and provide proof of principle for, an approach to help identify blood biomarkers for mood state. We measured whole-genome gene expression differences in blood samples from subjects with bipolar disorder that had low mood vs those that had high mood at the time of the blood draw, and separately, changes in gene expression in brain and blood of a mouse pharmacogenomic model. We then integrated our human blood gene expression data with animal model gene expression data, human genetic linkage/association data and human postmortem brain data, an approach called convergent functional genomics, as a Bayesian strategy for cross-validating and prioritizing findings. Topping our list of candidate blood biomarker genes we have five genes involved in myelination (Mbp, Edg2, Mag, Pmp22 and Ugt8), and six genes involved in growth factor signaling (Fgfr1, Fzd3, Erbb3, Igfbp4, Igfbp6 and Ptprm). All of these genes have prior evidence of differential expression in human postmortem brains from mood disorder subjects. A predictive score developed based on a panel of 10 top candidate biomarkers (five for high mood and five for low mood) shows sensitivity and specificity for high mood and low mood states, in two independent cohorts. Our studies suggest that blood biomarkers may offer an unexpectedly informative window into brain functioning and disease state.

Glutamine deprivation facilitates tumour necrosis factor induced bacterial translocation in Caco-2 cells by depletion of enterocyte fuel substrate

BACKGROUND AND AIMS

Factors that induce luminal bacteria to cross the intestinal epithelium following injury remain poorly defined. The aim of this study was to investigate the interaction between glutamine metabolism, energy supply, and inflammatory mediators in determining the translocation of non-pathogenic bacteria across cultured enterocytes.

METHODS

The effect of tumour necrosis factor alpha (TNF-alpha) on translocation of Escherichia coli C25 across Caco-2 epithelial monolayers was studied in the presence of products and inhibitors of glutamine metabolism. Simultaneous measurements of transepithelial electrical resistance (TEER) and flux of lucifer yellow were used to assess effects on the paracellular pathway. Lactate dehydrogenase release was used to monitor enterocyte integrity. Imaging of monolayers in these experimental conditions was undertaken with transmission electron microscopy.

RESULTS

Exposure to basolateral TNF-alpha (20 ng/ml) for six hours induced translocation of E coli across Caco-2 but only if accompanied by simultaneous glutamine depletion (p<0.01). Translocation was inhibited by addition of glutamine for two hours (p<0.01) but not by an isonitrogenous mixture of non-glutamine containing amino acids. Inhibition of glutamine conversion to alpha-ketoglutarate, but not blockade of glutathione or polyamine synthesis, also induced translocation in the presence of TNF-alpha. Manipulations that induced bacterial translocation were associated with a marked reduction in enterocyte ATP levels. No effect of these treatments on paracellular permeability or lactate dehydrogenase release was observed. Conditions in which translocation occurred were associated with the presence of bacteria within enterocyte vacuoles but not the paracellular space.

CONCLUSIONS

In inflammatory conditions, the availability of glutamine as an enterocyte fuel substrate is essential for the preservation of a functional barrier to microorganisms. In conditions of acute glutamine depletion, cytokine mediated bacterial translocation appears to be primarily a transcellular process.

Cell density-dependent proliferation in frequently-fed peripheral blood mononuclear cell cultures

BACKGROUND

Our goal was to produce granulocyte progenitor (CFU-G) and post-progenitor (CD15(+)CD11b(+/-)) cells for subsequent transplantation. We hypothesized that increasing the feeding frequency and maintaining constant densities may overcome inhibitory growth conditions (i.e. low pH) in high-density cultures.

METHODS

To study the effect of cell density on total cell expansion, differentiation and lactate production, 50% daily medium exchanges were used in cultures of peripheral blood mononuclear cells (PB MNC) maintained at constant densities (ranging from 5 x 10(4)cells/mL to 2.5 x 10(6)cells/mL).

RESULTS

We observed a significant increase in total cell expansion when the density was increased from 5 x 10(4) cells/mL to 1 x 10(6) cells/mL, but a further increase to 2.5 x 10(6)cells/mL resulted in a decline in cell expansion. Increasing feeding to 90% daily exchange in cultures with 2.5 x 10(6) cells/mL did not enhance cell expansion; nor did reducing the extent of feeding in cultures with 5 x 10(4) cells/mL to 10% daily exchange. We did not observe a relationship between cell density and the percentage of granulocyte progenitor and post-progenitor (CD15(+)CD11b(-/+)) cells. While specific lactate production (q(lac)) in cultures with 2.5 x 10(6) cells/mL was approximately 60% of those observed in lower density cultures by Day 13, this difference was largely eliminated by increasing the extent of feeding in cultures with 2.5 x 10(6) cells/mL.

DISCUSSION

Our results suggest that feeding rates must be adjusted according to cell density to maximize culture performance. They also suggest that cellular crowding on the culture surface can limit expansion in suspension (nonadherent) cultures.

Clinical-scale production of granulocyte progenitor and post-progenitor cells using daniplestim, leridistim, Progenipoietin, Promegapoietin and autologous plasma

BACKGROUND

Supplementation of PBPC autografts with ex vivo expanded PBMC may significantly reduce or eliminate the period of neutropenia associated with high-dose chemotherapy.

METHODS

Unmanipulated growth-factor mobilized PBMC were expanded in media containing daniplestim, leridistim, Promegapoietin, and Progenipoietin (DLPP) and 2% autologous plasma at 4 x 10(5) PBMC/mL, first in 25 cm(2) T-flasks, with sampling on Days 7, 10, 13 and 15, and then in 1264 cm(2) Nunclon Cell Factories, with sampling on Days 7 and 13.

RESULTS

In T25-flasks, maximal CFU-GM expansion ([38.2 +/- 9.5]-fold) occurred on Day 10, whereas maximal total cell expansion ([6.7 +/- 1.1]-fold) occurred on Day 15. Production of CD15(+)CD11b(-) and CD15(+)CD11b(+) granulocytic post-progenitors (3.0 +/- 0.4 x 10(6) and 3.7 +/- 0.9 x 10(6), respectively) was also maximal at Day 15. Compared with the previously studied combination of Flt3L, PIXY321, G-CSF, GM-CSF and Epo, the DLPP cocktail performed similarly, with the exception of yielding larger GM colonies at Day 10 and fewer granulocyte post-progenitors on Day 15. In Cell Factories, CFU-GM were expanded (31.6 +/- 14.5)-fold, while total nonadherent cells were expanded (2.6 +/- 0.5)-fold. The two stack Cell Factory cultures seeded with 1.0 x 10(8) unselected PBMC produced approximately 3.3 x 10(6) CFU-GM and 1.3 x 10(8) myeloid post-progenitors.

DISCUSSION

Whereas expansion of cell numbers, CFU-GM and granulocytic post-progenitors in Cell Factories mirrored that achieved in T25-flasks, future preclinical studies with the DLPP cytokine combination may be performed in small volumes, with subsequent translation to the larger volume Cell Factories. Sufficient expansion can be achieved using the DLPP cytokine combination in the Cell Factories to provide the numbers of progenitors required for clinical trials.

Selection of zinc fingers that bind single-stranded telomeric DNA in the G-quadruplex conformation

There is considerable interest in molecules that bind to telomeric DNA sequences and G-quadruplexes with specificity. Such molecules would be useful to test hypotheses for telomere length regulation, and may have therapeutic potential. The versatility and modular nature of the zinc finger motif makes it an ideal candidate for engineering G-quadruplex-binding proteins. Phage display technology has previously been widely used to screen libraries of zinc fingers for binding to novel duplex DNA sequences. In this study, a three-finger library has been screened for clones that bind to an oligonucleotide containing the human telomeric repeat sequence folded in the G-quadruplex conformation. The selected clones show a strong amino acid consensus, suggesting analogous modes of binding. Binding was found to be both sequence dependent and structure specific. This is the first example of an engineered protein that binds to G-quadruplex DNA, and represents a new type of binding interaction for a zinc finger protein.

Anti-Tumor CC49-zeta CD4 T cells possess both cytolytic and helper functions

The authors report that the nature of the T-cell-receptor--derived signal in normal CD4+ T cells can induce interleukin-2 (IL-2) secretion or perforin-mediated cytolytic activity. Normal human T cells were genetically modified to express the tumor antigen specific chimeric immune receptor, CC49-zeta. The CC49-zeta chimeric immune receptor is comprised of the intracellular signaling domains of the TCR CD3zeta protein fused to the single chain scFv of the humanized CC49 antibody, which binds the pan-adenocarcinoma tumor antigen TAG-72. Patient-specific T cells genetically modified to express the CC49-zeta receptor have been used in patients with colon cancer. The authors report that both CD4 and CD8 T cells expressing the CC49-zeta receptor mediated the major histocompatibility complex-unrestricted lysis of TAG-72--expressing tumor cells with comparable efficiency. However, although the CC49-zeta receptor mediated target cell lysis, it did not support the production of IL-2, even in the presence of CD28 stimulation. Robust IL-2 secretion and T-cell proliferation were observed when the same CD4 CC49-zeta T cells were stimulated through the CD28 receptor and endogenous T-cell receptor. These results indicate that CD4 T lymphocytes possess the capacity to act as both cytolytic and helper T cells and that this difference in effector function is controlled by the nature of the T-Cell receptor--derived signals.