Sex Differences Among Older Adults With Bipolar Disorder: Results From the Global Aging & Geriatric Experiments in Bipolar Disorder (GAGE-BD) Project.

OBJECTIVE: Sex-specific research in adult bipolar disorder (BD) is sparse and even more so among those with older age bipolar disorder (OABD). Knowledge about sex differences across the bipolar lifespan is urgently needed to target and improve treatment. To address this gap, the current study examined sex differences in the domains of clinical presentation, general functioning, and mood symptoms among individuals with OABD. METHODS: This Global Aging & Geriatric Experiments in Bipolar Disorder (GAGE-BD) study used data from 19 international studies including BD patients aged ≥50 years (N = 1,185: 645 women, 540 men).A comparison of mood symptoms between women and men was conducted initially using two-tailed t tests and then accounting for systematic differences between the contributing cohorts by performing generalized linear mixed models (GLMMs). Associations between sex and other clinical characteristics were examined using GLMM including: age, BD subtype, rapid cycling, psychiatric hospitalization, lifetime psychiatric comorbidity, and physical health comorbidity, with study cohort as a random intercept. RESULTS: Regarding depressive mood symptoms, women had higher scores on anxiety and hypochondriasis items. Female sex was associated with more psychiatric hospitalizations and male sex with lifetime substance abuse disorders. CONCLUSION: Our findings show important clinical sex differences and provide support that older age women experience a more severe course of BD, with higher rates of psychiatric hospitalization. The reasons for this may be biological, psychological, or social. These differences as well as underlying mechanisms should be a focus for healthcare professionals and need to be studied further.

Sociodemographic and clinical characteristics of people with oldest older age bipolar disorder in a global sample: Results from the global aging and geriatric experiments in bipolar disorder project.

OBJECTS: Studies of older age bipolar disorder (OABD) have mostly focused on "younger old" individuals. Little is known about the oldest OABD (OOABD) individuals aged ≥70 years old. The Global Aging and Geriatric Experiments in Bipolar Disorder (GAGE-BD) project provides an opportunity to evaluate the OOABD group to understand their characteristics compared to younger groups. METHODS: We conducted cross-sectional analyses of the GAGE-BD database, an integrated, harmonized dataset from 19 international studies. We compared the sociodemographic and clinical characteristics of those aged <50 (YABD, n = 184), 50-69 (OABD, n = 881), and ≥70 (OOABD, n = 304). To standardize the comparisons between age categories and all characteristics, we used multinomial logistic regression models with age category as the dependent variable, with each characteristic as the independent variable, and clustering of standard errors to account for the correlation between observations from each of the studies. RESULTS: OOABD and OABD had lower severity of manic symptoms (Mean YMRS = 3.3, 3.8 respectively) than YABD (YMRS = 7.6), and lower depressive symptoms (% of absent = 65.4%, and 59.5% respectively) than YABD (18.3%). OOABD and OABD had higher physical burden than YABD, especially in the cardiovascular domain (prevalence = 65% in OOABD, 41% in OABD and 17% in YABD); OOABD had the highest prevalence (56%) in the musculoskeletal domain (significantly differed from 39% in OABD and 31% in YABD which didn't differ from each other). Overall, OOABD had significant cumulative physical burden in numbers of domains (mean = 4) compared to both OABD (mean = 2) and YABD (mean = 1). OOABD had the lowest rates of suicidal thoughts (10%), which significantly differed from YABD (26%) though didn't differ from OABD (21%). Functional status was higher in both OOABD (GAF = 63) and OABD (GAF = 64), though only OABD had significantly higher function than YABD (GAF = 59). CONCLUSIONS: OOABD have unique features, suggesting that (1) OOABD individuals may be easier to manage psychiatrically, but require more attention to comorbid physical conditions; (2) OOABD is a survivor cohort associated with resilience despite high medical burden, warranting both qualitative and quantitative methods to better understand how to advance clinical care and ways to age successfully with BD.

Bipolar symptoms, somatic burden and functioning in older-age bipolar disorder: A replication study from the global aging & geriatric experiments in bipolar disorder database (GAGE-BD) project.

OBJECTIVES: The Global Aging & Geriatric Experiments in Bipolar Disorder Database (GAGE-BD) project pools archival datasets on older age bipolar disorder (OABD). An initial Wave 1 (W1; n = 1369) analysis found both manic and depressive symptoms reduced among older patients. To replicate this finding, we gathered an independent Wave 2 (W2; n = 1232, mean ± standard deviation age 47.2 ± 13.5, 65% women, 49% aged over 50) dataset. DESIGN/METHODS: Using mixed models with random effects for cohort, we examined associations between BD symptoms, somatic burden and age and the contribution of these to functioning in W2 and the combined W1 + W2 sample (n = 2601). RESULTS: Compared to W1, the W2 sample was younger (p < 0.001), less educated (p < 0.001), more symptomatic (p < 0.001), lower functioning (p < 0.001) and had fewer somatic conditions (p < 0.001). In the full W2, older individuals had reduced manic symptom severity, but age was not associated with depression severity. Age was not associated with functioning in W2. More severe BD symptoms (mania p ≤ 0.001, depression p ≤ 0.001) were associated with worse functioning. Older age was significantly associated with higher somatic burden in the W2 and the W1 + W2 samples, but this burden was not associated with poorer functioning. CONCLUSIONS: In a large, independent sample, older age was associated with less severe mania and more somatic burden (consistent with previous findings), but there was no association of depression with age (different from previous findings). Similar to previous findings, worse BD symptom severity was associated with worse functioning, emphasizing the need for symptom relief in OABD to promote better functioning.

Antibody-targeted T cells and natural killer cells for cancer immunotherapy.

BACKGROUND: Adoptive cell cancer therapies aim to re-engineer a patient's immune cells to mount an anti-cancer response. Chimeric antigen receptor T and natural killer cells have been engineered and proved successful in treating some cancers; however, the genetic methods for engineering are laborious, expensive, and inefficient and can cause severe toxicities when they over-proliferate. RESULTS: We examined whether the cell-killing capacity of activated T and NK cells could be targeted to cancer cells by anchoring antibodies to their cell surface. Using metabolic glycoengineering to introduce azide moieties to the cellular surface, we covalently attached a dibenzocyclooctyne-modified antibody using the strain-promoted alkyne azide cycloaddition reaction, creating antibody-conjugated T and NK cells. We targeted the immune cells to tumors possessing the xenoantigen, N-glycolyl neuraminic acid GM3 ganglioside, using the 14F7hT antibody. These activated T and NK cells are "armed" with tumour-homing capabilities that specifically lyses antigen-positive cancer cells without off-target toxicities. Moreover, when exposed to target cells, 14F7hT-conjugated T cells that are not preactivated exhibit increased perforin, granzyme, CD69, and CD25 expression and specific cell killing. CONCLUSIONS: This research shows the potential for a non-genetic method for redirecting cytotoxic immune cells as a feasible and effective approach for tumor-targeted cell immunotherapy.

Demographic and clinical associations to employment status in older-age bipolar disorder: Analysis from the GAGE-BD database project.

OBJECTIVE: The current literature on employment in older adults with bipolar disorder (OABD) is limited. Using the Global Aging and Geriatric Experiments in Bipolar Disorder Database (GAGE-BD), we examined the relationship of occupational status in OABD to other demographic and clinical characteristics. METHODS: Seven hundred and thirty-eight participants from 11 international samples with data on educational level and occupational status were included. Employment status was dichotomized as employed versus unemployed. Generalized linear mixed models with random intercepts for the study cohort were used to examine the relationship between baseline characteristics and employment. Predictors in the models included baseline demographics, education, psychiatric symptom severity, psychiatric comorbidity, somatic comorbidity, and prior psychiatric hospitalizations. RESULTS: In the sample, 23.6% (n = 174) were employed, while 76.4% were unemployed (n = 564). In multivariable logistic regression models, less education, older age, a history of both anxiety and substance/alcohol use disorders, more prior psychiatric hospitalizations, and higher levels of BD depression severity were associated with greater odds of unemployment. In the subsample of individuals less than 65 years of age, findings were similar. No significant association between manic symptoms, gender, age of onset, or employment status was observed. CONCLUSION: Results suggest an association between educational level, age, psychiatric severity and comorbidity in relation to employment in OABD. Implications include the need for management of psychiatric symptoms and comorbidity across the lifespan, as well as improving educational access for people with BD and skills training or other support for those with work-life breaks to re-enter employment and optimize the overall outcome.

Bipolar I and bipolar II subtypes in older age: Results from the Global Aging and Geriatric Experiments in Bipolar Disorder (GAGE-BD) project.

OBJECTIVES: The distinction between bipolar I disorder (BD-I) and bipolar II disorder (BD-II) has been a topic of long-lasting debate. This study examined differences between BD-I and BD-II in a large, global sample of OABD, focusing on general functioning, cognition and somatic burden as these domains are often affected in OABD. METHODS: Cross-sectional analyses were conducted with data from the Global Aging and Geriatric Experiments in Bipolar Disorder (GAGE-BD) database. The sample included 963 participants aged ≥50 years (714 BD-I, 249 BD-II). Sociodemographic and clinical factors were compared between BD subtypes including adjustment for study cohort. Multivariable analyses were conducted with generalized linear mixed models (GLMMs) and estimated associations between BD subtype and (1) general functioning (GAF), (2) cognitive performance (g-score) and (3) somatic burden, with study cohort as random intercept. RESULTS: After adjustment for study cohort, BD-II patients more often had a late onset ≥50 years (p = 0.008) and more current severe depression (p = 0.041). BD-I patients were more likely to have a history of psychiatric hospitalization (p < 0.001) and current use of anti-psychotics (p = 0.003). Multivariable analyses showed that BD subtype was not related to GAF, cognitive g-score or somatic burden. CONCLUSION: BD-I and BD-II patients did not differ in terms of general functioning, cognitive impairment or somatic burden. Some clinical differences were observed between the groups, which could be the consequence of diagnostic definitions. The distinction between BD-I and BD-II is not the best way to subtype OABD patients. Future research should investigate other disease specifiers in this population.

Bipolar symptoms, somatic burden, and functioning in older-age bipolar disorder: Analyses from the Global Aging & Geriatric Experiments in Bipolar Disorder Database project.

OBJECTIVE: Literature on older-age bipolar disorder (OABD) is limited. This first-ever analysis of the Global Aging & Geriatric Experiments in Bipolar Disorder Database (GAGE-BD) investigated associations among age, BD symptoms, comorbidity, and functioning. METHODS: This analysis used harmonized, baseline, cross-sectional data from 19 international studies (N = 1377). Standardized measures included the Young Mania Rating Scale (YMRS), Hamilton Depression Rating Scale (HAM-D), Montgomery-Asberg Depression Rating Scale (MADRS), and Global Assessment of Functioning (GAF). RESULTS: Mean sample age was 60.8 years (standard deviation [SD] 12.2 years), 55% female, 72% BD I. Mood symptom severity was low: mean total YMRS score of 4.3 (SD 5.4) and moderate-to-severe depression in only 22%. Controlled for sample effects, both manic and depressive symptom severity appeared lower among older individuals (p's < 0.0001). The negative relationship between older age and symptom severity was similar across sexes, but was stronger among those with lower education levels. GAF was mildly impaired (mean =62.0, SD = 13.3) and somatic burden was high (mean =2.42, SD = 1.97). Comorbidity burden was not associated with GAF. However, higher depressive (p < 0.0001) and manic (p < 0.0001) symptoms were associated with lower GAF, most strongly among older individuals. CONCLUSIONS: Findings suggest an attenuation of BD symptoms in OABD, despite extensive somatic burden. Depressive symptom severity was strongly associated with worse functioning in older individuals, underscoring the need for effective treatments of BD depression in older people. This international collaboration lays a path for the development of a better understanding of aging in BD.

Physical Health Burden Among Older Men and Women With Bipolar Disorder: Results From the Gage-Bd Collaboration.

OBJECTIVES: To compare the prevalence of physical morbidities among men and women with older adult bipolar disorder (OABD), and men with and without OABD. METHODS: Cross-sectional analysis of the collaborative Global Aging & Geriatric Experiments in Bipolar Disorder (GAGE-BD) database and non-OABD data from the Health in Men Study. OABD defined as bipolar disorder among adults aged greater than or equal to 50 years. Outcomes of interest were diseases affecting the cardiovascular, respiratory, gastrointestinal, renal, musculoskeletal and endocrinological systems. RESULTS: We examined 1407 participants with OABD aged 50-95 years, of whom 787 were women. More women than men showed evidence of morbidities affecting the respiratory, gastrointestinal, musculoskeletal and endocrinological systems. More men with than without OABD showed evidence of cardiovascular, renal and endocrinological diseases. CONCLUSION: GAGE-BD data showed that physical morbidities affect more women than men with OABD, and more men with than without OABD. The underlying reasons for these differences require clarification.

Symptom Severity Mixity in Older-Age Bipolar Disorder: Analyses From the Global Aging and Geriatric Experiments in Bipolar Disorder Database (GAGE-BD).

OBJECTIVE: Some individuals with bipolar disorder (BD) experience manic and depressive symptoms concurrently, but data are limited on symptom mixity in older age bipolar disorder (OABD). Using the Global Aging & Geriatric Experiments in Bipolar Disorder Database, we characterized mixity in OABD and associations with everyday function. METHODS: The sample (n = 805), from 12 international studies, included cases with both mania and depression severity ratings at a single timepoint. Four mixity groups were created: asymptomatic (A), mixed (Mix), depressed only (Dep), and manic only (Man). Generalized linear mixed models used mixity group as the predictor variable; cohort was included as a random intercept. Everyday function was assessed with the Global Assessment of Functioning score. RESULTS: Group proportions were Mix (69.6%; n = 560), followed by Dep (18.4%; n = 148), then A (7.8%; n = 63), then Man (4.2%; n= 34); levels of depression and mania were similar in Mix compared to Dep and Man, respectively. Everyday function was lowest in Mix, highest in A, and intermediate in Man and Dep. Within Mix, severity of depression was the main driver of worse functioning. Groups differed in years of education, with A higher than all others, but did not differ by age, gender, employment status, BD subtype, or age of onset. CONCLUSIONS: Mixed features predominate in a cross-sectional, global OABD sample and are associated with worse everyday function. Among those with mixed symptoms, functional status relates strongly to current depression severity. Future studies should include cognitive and other biological variables as well as longitudinal designs to allow for evaluation of causal effects.

Demographic and clinical characteristics of lithium-treated older adults with bipolar disorder.

OBJECTIVES: There is limited information on the characteristics of older adults with bipolar disorder (OABD) treated with lithium, along with safety concerns about its use by older adults. The aim of the present study is to describe the demographic and clinical characteristics of OABD receiving lithium therapy, using data from the Global Ageing & Geriatric Experiments in Bipolar Disorder (GAGE-BD). EXPERIMENTAL PROCEDURES: Cross-sectional analysis of the GAGE-BD dataset to determine differences and similarities between lithium users and non-users. We analysed data from 986 participants aged 50 years or older (mean age 63.5 years; 57.5% females) from 12 study sites. Two subgroups ('Lithium'; 'Non-lithium') were defined according to the current prescription of lithium. We compared several outcomes between these groups, controlling for age, gender, and study site. RESULTS: OABD treated with lithium had lower scores on depression rating scales and were less likely to be categorised as with moderate or severe depression. There was a lower proportion of lithium users than non-users among those with evidence of rapid cycling and non-bipolar psychiatric diagnoses. Assessment of global cognitive state and functionality indicated better performance among lithium users. The current use of antipsychotics was less frequent among lithium users, who also reported fewer cardiovascular comorbidities than non-users. CONCLUSION: We found several potentially relevant differences in the clinical profile of OABD treated with lithium compared with those treated with other mood stabilisers. However, the interpretation of the present results must take into account the methodological limitations inherent to the cross-sectional approach and data harmonisation.

Clinical correlates of late-onset versus early-onset bipolar disorder in a global sample of older adults.

OBJECTIVES: Late-onset bipolar disorder (LOBD) represents a significant subgroup of bipolar disorder (BD). However, knowledge for this group is mostly extrapolated from small studies in subjects with early/mixed age of illness onset. In this global sample of older adults with BD (OABD: ≥50 years old) we aim to characterize the sociodemographic and clinical presentation of LOBD (≥40 years at BD onset) compared to early-onset BD (EOBD: <40 years at BD onset). METHODS: The Global Aging and Geriatric Experiments in Bipolar Disorder consortium provided international data on 437 older age bipolar disorder participants. We compared LOBD versus EOBD on depression, mania, functionality, and physical comorbidities. Exploratory analyses were performed on participants with BD onset ≥50 years old. RESULTS: LOBD (n = 105) did not differ from EOBD (n = 332) on depression, mania, global functioning, nor employment status (p > 0.05). Late-onset bipolar disorder was associated with higher endocrine comorbidities (odds ratio = 1.48, [95%CI = 1.0,12.1], p = 0.03). This difference did not remain significant when subjects with BD onset ≥50 years old were analyzed. LIMITATIONS: This study is limited by the retrospective nature of the variable age of onset and the differences in evaluation methods across studies (partially overcame by harmonization processes). CONCLUSION: The present analysis is in favor of the hypothesis that LOBD might represent a similar clinical phenotype as classic EOBD with respect to core BD symptomatology, functionality, and comorbid physical conditions. Large-scale global collaboration to improve our understanding of BD across the lifespan is needed.

Next-generation sequencing-guided identification and reconstruction of antibody CDR combinations from phage selection outputs.

Next-generation sequencing (NGS) technologies have been employed in several phage display platforms for analyzing natural and synthetic antibody sequences and for identifying and reconstructing single-chain variable fragments (scFv) and antigen-binding fragments (Fab) not found by conventional ELISA screens. In this work, we developed an NGS-assisted antibody discovery platform by integrating phage-displayed, single-framework, synthetic Fab libraries. Due to limitations in attainable read and amplicon lengths, NGS analysis of Fab libraries and selection outputs is usually restricted to either VH or VL. Since this information alone is not sufficient for high-throughput reconstruction of Fabs, we developed a rapid and simple method for linking and sequencing all diversified CDRs in phage Fab pools. Our method resulted in a reliable and straightforward platform for converting NGS information into Fab clones. We used our NGS-assisted Fab reconstruction method to recover low-frequency rare clones from phage selection outputs. While previous studies chose rare clones for rescue based on their relative frequencies in sequencing outputs, we chose rare clones for reconstruction from less-frequent CDRH3 lengths. In some cases, reconstructed rare clones (frequency ∼0.1%) showed higher affinity and better specificity than high-frequency top clones identified by Sanger sequencing, highlighting the significance of NGS-based approaches in synthetic antibody discovery.

Modular Chimeric Antigen Receptor Systems for Universal CAR T Cell Retargeting.

The engineering of T cells through expression of chimeric antigen receptors (CARs) against tumor-associated antigens (TAAs) has shown significant potential for use as an anti-cancer therapeutic. The development of strategies for flexible and modular CAR T systems is accelerating, allowing for multiple antigen targeting, precise programming, and adaptable solutions in the field of cellular immunotherapy. Moving beyond the fixed antigen specificity of traditional CAR T systems, the modular CAR T technology splits the T cell signaling domains and the targeting elements through use of a switch molecule. The activity of CAR T cells depends on the presence of the switch, offering dose-titratable response and precise control over CAR T cells. In this review, we summarize developments in universal or modular CAR T strategies that expand on current CAR T systems and open the door for more customizable T cell activity.

Post-translational Assembly of Protein Parts into Complex Devices by Using SpyTag/SpyCatcher Protein Ligase.

Exploiting the innate modularity of proteins has allowed advances across the fields of synthetic biology and biotechnology. By using standardized protein components as building blocks, complex, multiprotein assemblies with sophisticated functions can be generated; feats previously not possible with strictly genetic-engineering approaches. The development of strategies for protein assembly is accelerating, pushing the boundaries of protein architecture. SpyTag and SpyCatcher protein ligase is a recent advance in this field that allows plug-and-play modularity by harnessing post-translational protein assembly. Herein, we review the latest applications of this powerful tool including novel enzyme assemblies, modularizing protein display, and the generation of antibody and antibody-like "devices" by using SpyTag/SpyCatcher technology.

A Single-Framework Synthetic Antibody Library Containing a Combination of Canonical and Variable Complementarity-Determining Regions.

Synthetic antibody libraries have been used to generate antibodies with favorable biophysical and pharmacological properties. Here, we describe the design, construction, and validation of a phage-displayed antigen-binding fragment (Fab) library built on a modified trastuzumab framework with four fixed and two diversified complementarity-determining regions (CDRs). CDRs L1, L2, H1, and H2 were fixed to preserve the most commonly observed "canonical" CDR conformation preferred by the modified trastuzumab Fab framework. The library diversity was engineered within CDRs L3 and H3 by use of custom-designed trinucleotide phosphoramidite mixes and biased towards human antibody CDR sequences. The library contained ≈7.6 billion unique Fabs, and >95 % of the library correctly encoded both diversified CDR sequences. We used this library to conduct selections against the human epidermal growth factor receptor-3 extracellular domain (HER3-ECD) and compared the CDR diversity of the naïve library and the anti-HER3 selection pool by use of next-generation sequencing. The most commonly observed CDR combination isolated, named Her3-3, was overexpressed and purified in Fab and immunoglobulin G (IgG) formats. Fab HER3-3 bound to HER3-ECD with a KD value of 2.14 nm and recognized cell-surface HER3. Although HER3-3 IgG bound to cell-surface HER3, it did not inhibit the proliferation of HER3-positive cells. Near-infrared imaging showed that Fab HER3-3 selectively accumulated in a murine HER3-postive xenograft, thus providing a lead for the development of HER3 imaging probes.

Steeper Slope of Age-Related Changes in White Matter Microstructure and Processing Speed in Bipolar Disorder.

OBJECTIVES: Bipolar disorder (BD) is associated with compromised white matter (WM) integrity and deficits in processing speed (PS). Few studies, however, have investigated age relationships with WM structure and cognition to understand possible changes in brain health over the lifespan. This investigation explored whether BD and healthy counterpart (HC) participants exhibited differential age-related associations with WM and cognition, which may be suggestive of accelerated brain and cognitive aging. DESIGN: Cross-sectional study. SETTING: University of California San Diego and the Veterans Administration San Diego Healthcare System. PARTICIPANTS: 33 euthymic BD and 38 HC participants. MEASUREMENTS: Diffusion tensor imaging was acquired as a measure of WM integrity, and tract-specific fractional anisotropy (FA) was extracted utilizing the Johns Hopkins University probability atlas. PS was assessed with the Number and Letter Sequencing conditions of the Delis-Kaplan Executive Function System Trail Making Test. RESULTS: BD participants demonstrated slower PS compared with the HC group, but no group differences were found in FA across tracts. Multiple linear regressions revealed a significant group-by-age interaction for the right uncinate fasciculus, the left hippocampal portion of the cingulum, and for PS, such that older age was associated with lower FA values and slower PS in the BD group only. The relationship between age and PS did not significantly change after accounting for uncinate FA, suggesting that the observed age associations occur independently. CONCLUSIONS: Results provide support for future study of the accelerated aging hypothesis by identifying markers of brain health that demonstrate a differential age association in BD.

Fusing Functional MRI and Diffusion Tensor Imaging Measures of Brain Function and Structure to Predict Working Memory and Processing Speed Performance among Inter-episode Bipolar Patients.

Evidence for abnormal brain function as measured with diffusion tensor imaging (DTI) and functional magnetic resonance imaging (fMRI) and cognitive dysfunction have been observed in inter-episode bipolar disorder (BD) patients. We aimed to create a joint statistical model of white matter integrity and functional response measures in explaining differences in working memory and processing speed among BD patients. Medicated inter-episode BD (n=26; age=45.2±10.1 years) and healthy comparison (HC; n=36; age=46.3±11.5 years) participants completed 51-direction DTI and fMRI while performing a working memory task. Participants also completed a processing speed test. Tract-based spatial statistics identified common white matter tracts where fractional anisotropy was calculated from atlas-defined regions of interest. Brain responses within regions of interest activation clusters were also calculated. Least angle regression was used to fuse fMRI and DTI data to select the best joint neuroimaging predictors of cognitive performance for each group. While there was overlap between groups in which regions were most related to cognitive performance, some relationships differed between groups. For working memory accuracy, BD-specific predictors included bilateral dorsolateral prefrontal cortex from fMRI, splenium of the corpus callosum, left uncinate fasciculus, and bilateral superior longitudinal fasciculi from DTI. For processing speed, the genu and splenium of the corpus callosum and right superior longitudinal fasciculus from DTI were significant predictors of cognitive performance selectively for BD patients. BD patients demonstrated unique brain-cognition relationships compared to HC. These findings are a first step in discovering how interactions of structural and functional brain abnormalities contribute to cognitive impairments in BD.

Increased cerebral blood flow associated with better response inhibition in bipolar disorder.

Impairment on inhibitory tasks has been well documented in bipolar disorder (BD). Differences in cerebral blood flow (CBF) between BD patients and healthy comparison (HC) participants have also been reported. Few studies have examined the relationship between cognitive performance and regional CBF in this patient population. We hypothesized that group differences on an inhibitory task (the Delis-Kaplan Executive Function Scale's Color-Word Inhibition task) would be associated with differential CBF in bilateral anterior cingulate cortex (ACC), inferior parietal lobule (IPL) and dorsolateral prefrontal cortex (DLPFC) regions. Whole brain resting CBF was measured using Multiphase Pseudocontinuous Arterial Spin Labeling MR imaging for 28 euthymic BD and 36 HC participants. Total gray matter (GM) CBF was measured, and regional CBF values were extracted for each region of interest (ROI) using Freesurfer-based individual parcellations. Group, CBF, and group-by-CBF interaction were examined as predictors of inhibition performance. Groups did not differ in age, gender or education. BD patients performed significantly worse on Color-Word inhibition. There were no significant group differences in CBF in either total GM or in any ROI. There was a group by CBF interaction in the bilateral ACC, right IPL and right DLPFC such that better inhibitory performance was generally associated with higher resting state CBF in BD subjects, but not HC participants. Although CBF was not abnormal in this euthymic BD sample, results confirm previous reports of inter-episode inhibitory deficits and indicate that the perfusion-cognition relationship is different in BD compared to HC individuals.

Abnormalities of brain response during encoding into verbal working memory among euthymic patients with bipolar disorder.

OBJECTIVES: Individuals with bipolar disorder (BD) have trait-like deficits in attention and working memory (WM). A fundamental dissociation for most verbal WM theories involves the separation of sensory-perceptual encoding, reliant upon attention, from the maintenance of this information in WM proper. The present study examined if patients with BD demonstrate differential neural changes in encoding and maintenance WM processes that underlie cognitive impairment. METHODS: Event-related functional magnetic resonance imaging during a delayed match-to-sample WM paradigm was employed in 23 inter-episode medicated patients with BD and 23 demographically similar healthy comparison participants. We examined brain regions during encoding and maintenance task intervals to identify regions that demonstrated differential effects between groups. Medication effects and functional connectivity between prefrontal cortex and basal ganglia/thalamus were examined during the encoding interval due to the importance of these regions and the connection among them for encoding into WM. RESULTS: Patients with BD exhibited deficits in task accuracy and attenuated brain response during the encoding interval in areas of the prefrontal cortex, caudate, thalamus, and posterior visual regions. In contrast, patients with BD exhibited hyperactivation in posterior sensory regions during the maintenance interval. Among the BD group, those with greater medication load exhibited the greatest brain response within the prefrontal cortex. CONCLUSIONS: Reduction in activation during the encoding interval suggests that attentional deficits underlie WM deficits in patients with BD. These deficits appear to be trait-like in so far as they were observed during periods of euthymia in patients with BD. Medication effects remain to be further explored as there was evidence of prefrontal changes dependent on medication load.