High-Resolution Histological Landscape of AAV DNA Distribution in Cellular Compartments and Tissues following Local and Systemic Injection

Adeno-associated virus (AAV) is one of the most important gene delivery vehicles for in vivo gene therapy. Intramuscular (i.m.) and intravascular (i.v.) injection are commonly used for AAV gene transfer. Unfortunately, the fate of AAV vectors following administration remains unclear at the histological level. Taking advantage of RNAscope, a recently developed in situ hybridization technique that can reveal high-resolution viral DNA localization information, in this study, we evaluated body-wide distribution of an AAV9 vector in the context of the cell and tissue microenvironments. We observed distinctive kinetics of cell and nuclear entry of the AAV DNA in striated muscle and liver following i.m. and i.v. injection. We also found characteristic distribution patterns of the AAV DNA in various histological structures in internal organs, including gonads and lymph nodes, following i.v. injection. Finally, we showed significantly body-wide spreading of the AAV DNA following i.m. injection. These results add a new dimension to our understanding of AAV transduction biology and provide a basis for assessing the full impact of AAV gene therapy.

Depressive symptoms and cerebral microvascular disease in adults with Type 1 diabetes mellitus

AIM

To assess the prevalence of, and risk factors for, depressive symptoms, comparing a sample of middle-aged adults with and without juvenile-onset Type 1 diabetes mellitus, and to determine if depressive symptoms were associated with white matter hyperintensity volume among those with Type 1 diabetes.

METHODS

Depressive symptoms and white matter hyperintensities were compared between adults (age range 30-65 years) with juvenile-onset Type 1 diabetes (n=130) and adults without Type 1 diabetes (n=133). The association of Type 1 diabetes with depression was computed before and after adjustment for white matter hyperintensities. Among the Type 1 diabetes group, the primary associations of interest were between depressive symptoms (Beck Depression Inventory score ≥10) and white matter hyperintensities (n=71), hyperglycaemia and physical activity. Associations between depressive symptoms and diabetes-related complications, cognitive impairment, smoking and self-reported disability were examined. Analyses were controlled for education, sex, age and antidepressant use.

RESULTS

Depressive symptoms were more prevalent among those with vs those without Type 1 diabetes (28% vs 3%; P<0.001). White matter hyperintensities explained 40% of the association of Type 1 diabetes with depressive symptoms, while Type 1 diabetes had a direct effect of 68% on depressive symptoms. Among those with Type 1 diabetes, depressive symptoms were related to white matter hyperintensity volume, a 16-year average HbA1c ≥58 mmol/mol (7.5%), and lower physical activity levels. Associations with other characteristics were not significant.

CONCLUSION

These findings suggest a cerebrovascular origin for depressive symptoms in adults with Type 1 diabetes, perhaps triggered by hyperglycaemia. Future longitudinal studies should investigate whether targeting hyperglycaemia and physical inactivity alleviates depressive symptoms, possibly by slowing the development of cerebral microvascular disease, in people with Type 1 diabetes.

Association between change in brain gray matter volume, cognition, and depression severity: Pre- and post- antidepressant pharmacotherapy for late-life depression

Late-life depression (LLD) is associated with cognitive impairments and reduced gray matter volume (GMV); however the mechanisms underlying this association are not well understood. The goal of this study was to characterize changes in depression severity, cognitive function, and brain structure associated with pharmacologic antidepressant treatment for LLD. We administered a detailed neurocognitive battery and conducted structural magnetic resonance imaging (MRI) on 26 individuals with LLD, pre-/post-a 12-week treatment trial with venlafaxine. After calculating changes in cognitive performance, GMV, and depression severity, we calculated Pearson's correlations, performed permutation testing, and false discovery rate correction. We found that loss of GMV over 12 weeks in the superior orbital frontal gyrus was associated with less improvement in depression severity and that increased GMV in the same was associated with greater improvement in depression severity. We detected no associations between changes in cognitive performance and improvements in either depressive symptoms or changes in GMV.

Intrinsic functional connectivity in late-life depression: trajectories over the course of pharmacotherapy in remitters and non-remitters

Previous studies in late-life depression (LLD) have found that patients have altered intrinsic functional connectivity in the dorsal default mode network (DMN) and executive control network (ECN). We aimed to detect connectivity differences across a treatment trial among LLD patients as a function of remission status. LLD patients (N=37) were enrolled into a 12-week trial of venlafaxine and underwent five functional magnetic resonance imaging resting state scans during treatment. Patients had no history of drug abuse, psychosis, dementia/neurodegenerative diseases or medical conditions with known effects on mood. We investigated whether there were differences in three networks: DMN, ECN and anterior salience network connectivity, as well as a whole brain centrality measure (eigenvector centrality). We found that remitters showed increases in ECN connectivity in the right precentral gyrus and decreases in DMN connectivity in the right inferior frontal gyrus and supramarginal gyrus. The ECN and DMN had regions (middle temporal gyrus and bilateral middle/inferior temporal/fusiform gyrus, respectively) that showed reversed effects (decreased ECN and increased DMN, respectively). Early changes in functional connectivity can occur after initial medication exposure. This study offers new data, indicating that functional connectivity changes differ depending on treatment response and can occur shortly after exposure to antidepressant medication.

A Systematic Review of Opioid and Benzodiazepine Misuse in Older Adults

OBJECTIVE

The authors assessed the prevalence of opioid and benzodiazepine prescription drug misuse in older adults, the risk factors associated with misuse, and age-appropriate interventions.

METHODS

Following PRISMA guidelines, a literature search of PubMed, PsycINFO, and EMBASE for peer-reviewed journal articles in English through April 2014 with updates through November 2015 was conducted for reports on misuse of prescription benzodiazepines and opioids in older adults. Relevant publications were reviewed that included participants age ≥65 years. Reference lists were manually searched for key identified articles and geriatric journals through April 2016. Information on the study design, sample, intervention, comparators, outcome, time frame, and risk of bias were abstracted for each article.

RESULTS

Of 4,932 reviewed reports, 15 were included in this systematic review. Thirteen studies assessed the prevalence of prescription drug misuse and included studies related to opioid shopping behavior, assessment of morbidity and mortality associated with opioid and/or benzodiazepine use, frequency and characteristics of opioid prescribing, frequency of substance use disorders and nonprescription use of pain relievers, and health conditions and experiences of long-term benzodiazepine users. One study identified risk factors for misuse, and one study described the effects of provider education and an electronic support tool as an intervention.

CONCLUSION

There is a dearth of high quality research on prescription drug misuse in older adults. Existing studies are heterogeneous, making it difficult to draw broad conclusions. The need for further research specific to prescription drug misuse among older adults is discussed.

Subsyndromal depression and anxiety in older adults: health related, functional, cognitive and diagnostic implications

Subsyndromal depression in later life is common in primary care. Comorbid anxiety disorders could exacerbate the negative effect of subsyndromal depression on functioning, health-related quality of life, comorbidity and/or cognition. We examined anxiety disorders co-existing with subsyndromal depression in participants ≥ age 50 in an NIH trial of Problem Solving Therapy for Primary Care for indicated prevention of major depression. There were 247 participants, with Centers for Epidemiologic Studies - Depression scores ≥ 11. Participants could have multiple psychiatric diagnoses: 22% of the sample had no DSM IV diagnosis; 39% of the sample had only 1 DSM IV diagnosis; 28% had 2 diagnoses; 6% had 3 DSM IV diagnoses; 4% had 4 DSM IV diagnoses; and 1% had 5 diagnoses. Furthermore, 34% of participants had a current comorbid DSM IV diagnosis of a syndromal anxiety disorder. We hypothesized that those with subsyndromal depression, alone relative to those with co-existing anxiety disorders, would report better health-related quality of life, less disability, less medical comorbidity and less cognitive impairment. However, there were no differences in quality of life based on the SF 12 nor in disability based on Late Life Function and Disability Instrument scores. There were no differences in medical comorbidity based on the Cumulative Illness Scale-Geriatrics scale scores nor in cognitive function based on the Executive Interview (EXIT), Hopkins Verbal Learning Test-Revised and Mini-Mental Status Exam. Our findings suggest that about one third of participants 50 years and older with subsyndromal depression have comorbid anxiety disorders; however, this does not appear to be associated with worse quality of life, functioning, disability, cognitive function or medical comorbidity.

Effects of positive and negative life events on time to depression onset: an analysis of additivity and timing

While the relationship of life events to depression onset has occupied researchers for almost a quarter of a century, few studies have attempted to account for either the temporal patterning of events relative to episode onset, or, the effect of multiple events in a study period. In this report, we attempt to address the issues of timing of events, multiple events (both positive and negative) and multiple aspects (both positivity and negativity) of single events on latency time to depression onset, while simultaneously accounting for possible decay in the effects of events over time. We use the proportional hazards approach to model the effects of life events and consider modelling the change in impact of events with the passage of time. After interviewing 142 recurrent unipolar patients using the Life Events and Difficulties Schedule, we rated severity and positivity of life events reported during the 6-month period prior to onset. As we hypothesized, additional life events occurring after an initial provoking agent level event significantly alter the risk of illness onset. Additional severely threatening events decrease the time to onset, but positive events do not appear to delay onset. Interestingly, seemingly neutral events had a highly significant effect in shortening the time to onset. We note the many limitations imposed on the interpretation of these findings related to the selected group of subjects studied and encourage those who have more generalizable data to apply these methods of analysis.

Imipramine and sexual dysfunction during the long-term treatment of recurrent depression

Ninety patients in the maintenance therapy phase of the Pittsburgh Study of Maintenance Therapies in Recurrent Depression (Frank et al., 1990) were studied to determine possible relationships between the type of therapy (imipramine versus no drug) and the level of sexual functioning. The level of sexual functioning was determined by a composite subscale score of the Social Adjustment Scale which assessed (1) current level of enjoyment and interest in sex; (2) change in interest; (3) current frequency of sexual intercourse; (4) change in frequency; and (5) pain and/or difficulty reaching orgasm. Loss of libido was assessed by both the Hamilton Rating Scale for Depression and the SCL-90. Logistic regression analysis revealed no relationship between treatment with active imipramine and sexual functioning for the total group, or for females alone. Analysis of males alone revealed a decreased interest in sex among those treated with imipramine, but no significant differences in frequency or problems. The implications for maintenance pharmacotherapy and the cost/benefit ratio of unacceptable side effects versus drug efficacy are discussed.