Apolipoprotein E2 Expression Alters Endosomal Pathways in a Mouse Model With Increased Brain Exosome Levels During Aging.

The polymorphic APOE gene is the greatest genetic determinant of sporadic Alzheimer's disease risk: the APOE4 allele increases risk, while the APOE2 allele is neuroprotective compared with the risk-neutral APOE3 allele. The neuronal endosomal system is inherently vulnerable during aging, and APOE4 exacerbates this vulnerability by driving an enlargement of early endosomes and reducing exosome release in the brain of humans and mice. We hypothesized that the protective effects of APOE2 are, in part, mediated through the endosomal pathway. Messenger RNA analyses showed that APOE2 leads to an enrichment of endosomal pathways in the brain when compared with both APOE3 and APOE4. Moreover, we show age-dependent alterations in the recruitment of key endosomal regulatory proteins to vesicle compartments when comparing APOE2 to APOE3. In contrast to the early endosome enlargement previously shown in Alzheimer's disease and APOE4 models, we detected similar morphology and abundance of early endosomes and retromer-associated vesicles within cortical neurons of aged APOE2 targeted-replacement mice compared with APOE3. Additionally, we observed increased brain extracellular levels of endosome-derived exosomes in APOE2 compared with APOE3 mice during aging, consistent with enhanced endosomal cargo clearance by exosomes to the extracellular space. Our findings thus demonstrate that APOE2 enhances an endosomal clearance pathway, which has been shown to be impaired by APOE4 and which may be protective due to APOE2 expression during brain aging.

Brain apolipoprotein E levels in mice challenged by a Western diet increase in an allele-dependent manner.

Human apolipoprotein E (APOE) is the greatest determinant of genetic risk for memory deficits and Alzheimer's disease (AD). While APOE4 drives memory loss and high AD risk, APOE2 leads to healthy brain aging and reduced AD risk compared to the common APOE3 variant. We examined brain APOE protein levels in humanized mice homozygous for these alleles and found baseline levels to be age- and isoform-dependent: APOE2 levels were greater than APOE3, which were greater than APOE4. Despite the understanding that APOE lipoparticles do not traverse the blood-brain barrier, we show that brain APOE levels are responsive to dietary fat intake. Challenging mice for 6 months on a Western diet high in fat and cholesterol increased APOE protein levels in an allele-dependent fashion with a much greater increase within blood plasma than within the brain. In the brain, APOE2 levels responded most to the Western diet challenge, increasing by 20 % to 30 %. While increased lipoparticles are generally deleterious in the periphery, we propose that higher brain APOE2 levels may represent a readily available pool of beneficial lipid particles for neurons.

Social regulation of immediate early gene induction in gonadotropin releasing-hormone 1 neurons and singing behavior in canaries (Serinus canaria).

Social cues modulate the neuroendocrine control of reproduction. However, the neural systems involved in the integration of social cues are not well described. Gonadotropin-releasing hormone 1 (GnRH1) cells in the preoptic area (POA) are the final common node that links the brain with peripheral reproductive physiology. These experiments investigated whether induction of the immediate early gene, EGR1, in anatomically localized GnRH1 cell populations in Border canaries is regulated by the social environment. First, we characterized behavioral modifications in singing behavior and found males paired with a female for 2 weeks significantly reduced many aspects of singing behavior. However, paired males had a significantly higher percentage of GnRH1 cells co-labeled with EGR1. The second experiment manipulated the social environment by pairing males and females in mixed sex dyads, same sex dyads or housed birds in isolation. Only when birds are paired in mixed sex dyads was there a significantly greater percentage of GnRH1 cells expressing EGR1 cells. Increased GnRH1-EGR1 co-expression was localized to the rostral POA. These data reveal that discrete GnRH1 cells are involved in the neural integration of specific social cues and support the hypothesis that the POA exhibits functional topography related to courtship and sexual behaviors.

Recurrence Rates in Patients With Cervical Cancer Treated With Abdominal Versus Minimally Invasive Radical Hysterectomy: A Multi-Institutional Retrospective Review Study.

PURPOSE: To compare the disease-free survival (DFS) between open and minimally invasive radical hysterectomies (RH) performed in academic medical institutions. METHODS: Retrospective multi-institutional review of patients undergoing RH for stage IA1 (with lymphovascular invasion), IA2, and IB1 squamous, adenocarcinoma, or adenosquamous carcinoma between January 1, 2010 and December 31, 2017. RESULTS: Of 815 patients, open RH was performed in 255 cases (29.1%) and minimally invasive RH in 560 cases (70.9%). There were 19 (7.5%) recurrences in the open RH and 51 (9.1%) recurrences in the minimally invasive group (P = .43). Risk-adjusted analysis revealed that minimally invasive RH was independently associated with an increased hazard of recurrence (aHR, 1.88; 95% CI, 1.04 to 3.25). Other factors independently associated with an increased hazard of recurrence included tumor size, grade, and adjuvant radiation. Conization before surgery was associated with lower recurrence risk (aHR, 0.4; 95% CI, 0.23 to 0.71). There was no difference in OS in the unadjusted analysis (HR, 1.14; 95% CI, 0.61 to 2.11) or after risk adjustment (aHR, 1.01; 95% CI, 0.5 to 2.2). Of 264 patients with tumors ≤ 2 cm on final pathology (excluding those with no residual tumor on final pathology), 2/82 (2.4%) recurred in the open RH group and 16/182 (8.8%) in the minimally invasive RH group (P = .058). In propensity score matching analysis, 7/159 (4.4%) recurrences were noted in the open RH group and 18/156 (11.5%) in the minimally invasive RH group (P = .019). Survival analysis revealed an increased risk of recurrence in the minimally invasive group in propensity-matched cohort (HR, 2.83; 95% CI, 1.1 to 7.18). CONCLUSION: In this retrospective series, patients undergoing minimally invasive radical hysterectomy, including those with tumor size ≤ 2 cm on final pathology, had inferior DFS but not overall survival in the entire cohort.

Trends in surgical complexity and treatment modalities utilized in the management of ovarian cancer in an era of neoadjuvant chemotherapy.

OBJECTIVES: To investigate the impact of the increased use of neoadjuvant chemotherapy on the complexity of cytoreductive surgeries for ovarian cancer. METHODS: Using the National Cancer Database, we performed a retrospective cohort study of women diagnosed between 2004 and 2015 with stage III or IV epithelial ovarian cancer who underwent either primary cytoreductive surgery (PDS) followed by adjuvant chemotherapy, neoadjuvant chemotherapy (NACT) followed by interval debulking surgery. Cases were assigned a surgical complexity category as 1) Inadequate, 2) Low, 3) Moderate and, 4) High complexity. The primary outcome was the trend in surgical complexity over time. Secondary outcomes included temporal trends in treatment modality, perioperative mortality, and survival. RESULTS: At total of 52,582 (76.3%) underwent PDS and 16,307 (23.7%) underwent NACT. The utilization of NACT increased from 7.7% in 2004 to 27.8% in 2015 (p-trend < 0.001). Patients undergoing moderate complexity surgeries increased from 28.9% to 33.5% and high complexity surgeries from 26.3% to 30% (p-trend < 0.001, for both). Trends in increasing surgical complexity were seen in both NACT and PDS cohorts. This increase in surgical complexity was seen most profoundly at the high-volume centers. Overall 30-day mortality decreased from 3.4% in 2004 to 1.4% in 2015; and 90-day mortality decreased from 7.6% to 4%. During the same time, 5-year survival increased from 39.7% to 49%. CONCLUSIONS: Increase in the utilization of NACT is associated with decreased 30- and 90-day mortality and increase in five-year survival. Moreover, the overall complexity of ovarian cancer surgery has increased in both PDS and NACT cohorts.

Apolipoprotein E4 genotype compromises brain exosome production.

In addition to being the greatest genetic risk factor for Alzheimer's disease, expression of the ɛ4 allele of apolipoprotein E can lead to cognitive decline during ageing that is independent of Alzheimer's amyloid-ß and tau pathology. In human post-mortem tissue and mouse models humanized for apolipoprotein E, we examined the impact of apolipoprotein E4 expression on brain exosomes, vesicles that are produced within and secreted from late-endocytic multivesicular bodies. Compared to humans or mice homozygous for the risk-neutral ɛ3 allele we show that the ɛ4 allele, whether homozygous or heterozygous with an ɛ3 allele, drives lower exosome levels in the brain extracellular space. In mice, we show that the apolipoprotein E4-driven change in brain exosome levels is age-dependent: while not present at age 6 months, it is detectable at 12 months of age. Expression levels of the exosome pathway regulators tumor susceptibility gene 101 (TSG101) and Ras-related protein Rab35 (RAB35) were found to be reduced in the brain at the protein and mRNA levels, arguing that apolipoprotein E4 genotype leads to a downregulation of exosome biosynthesis and release. Compromised exosome production is likely to have adverse effects, including diminishing a cell's ability to eliminate materials from the endosomal-lysosomal system. This reduction in brain exosome levels in 12-month-old apolipoprotein E4 mice occurs earlier than our previously reported brain endosomal pathway changes, arguing that an apolipoprotein E4-driven failure in exosome production plays a primary role in endosomal and lysosomal deficits that occur in apolipoprotein E4 mouse and human brains. Disruption of these interdependent endosomal-exosomal-lysosomal systems in apolipoprotein E4-expressing individuals may contribute to amyloidogenic amyloid-ß precursor protein processing, compromise trophic signalling and synaptic function, and interfere with a neuron's ability to degrade material, all of which are events that lead to neuronal vulnerability and higher risk of Alzheimer's disease development. Together, these data suggest that exosome pathway dysfunction is a previously unappreciated component of the brain pathologies that occur as a result of apolipoprotein E4 expression.

The Endosomal-Lysosomal Pathway Is Dysregulated by APOE4 Expression in Vivo.

Possession of the ε4 allele of apolipoprotein E (APOE) is the major genetic risk factor for late-onset Alzheimer's disease (AD). Although numerous hypotheses have been proposed, the precise cause of this increased AD risk is not yet known. In order to gain a more comprehensive understanding of APOE4's role in AD, we performed RNA-sequencing on an AD-vulnerable vs. an AD-resistant brain region from aged APOE targeted replacement mice. This transcriptomics analysis revealed a significant enrichment of genes involved in endosomal-lysosomal processing, suggesting an APOE4-specific endosomal-lysosomal pathway dysregulation in the brains of APOE4 mice. Further analysis revealed clear differences in the morphology of endosomal-lysosomal compartments, including an age-dependent increase in the number and size of early endosomes in APOE4 mice. These findings directly link the APOE4 genotype to endosomal-lysosomal dysregulation in an in vivo, AD pathology-free setting, which may play a causative role in the increased incidence of AD among APOE4 carriers.

Apolipoprotein E4 causes early olfactory network abnormalities and short-term olfactory memory impairments.

While apolipoprotein (Apo) E4 is linked to increased incidence of Alzheimer's disease (AD), there is growing evidence that it plays a role in functional brain irregularities that are independent of AD pathology. However, ApoE4-driven functional differences within olfactory processing regions have yet to be examined. Utilizing knock-in mice humanized to ApoE4 versus the more common ApoE3, we examined a simple olfactory perceptual memory that relies on the transfer of information from the olfactory bulb (OB) to the piriform cortex (PCX), the primary cortical region involved in higher order olfaction. In addition, we have recorded in vivo resting and odor-evoked local field potentials (LPF) from both brain regions and measured corresponding odor response magnitudes in anesthetized young (6-month-old) and middle-aged (12-month-old) ApoE mice. Young ApoE4 compared to ApoE3 mice exhibited a behavioral olfactory deficit coinciding with hyperactive odor-evoked response magnitudes within the OB that were not observed in older ApoE4 mice. Meanwhile, middle-aged ApoE4 compared to ApoE3 mice exhibited heightened response magnitudes in the PCX without a corresponding olfactory deficit, suggesting a shift with aging in ApoE4-driven effects from OB to PCX. Interestingly, the increased ApoE4-specific response in the PCX at middle-age was primarily due to a dampening of baseline spontaneous activity rather than an increase in evoked response power. Our findings indicate that early ApoE4-driven olfactory memory impairments and OB network abnormalities may be a precursor to later network dysfunction in the PCX, a region that not only is targeted early in AD, but may be selectively vulnerable to ApoE4 genotype.

Speculum Lubrication and Patient Comfort: A Meta-Analysis of Randomized Controlled Trials.

OBJECTIVE: The aim of the study was to examine the effect of water-based gel lubrication in decreasing discomfort during speculum examination. MATERIALS AND METHODS: Searches of standard databases were performed. Randomized controlled trials comparing speculums lubricated with water-based gel to no lubrication or water alone in women undergoing gynecologic examinations were included. Selected studies were required to report on the outcome of discomfort experienced during the examination. Six studies met the criteria. Two reviewers independently performed the search and excluded articles that did not meet the inclusion criteria. The primary outcome was change in the visual analog scale (VAS) measure of discomfort. Pooled mean differences and 95% confidence interval (CI) were calculated and heterogeneity was assessed. RESULTS: Five studies, totaling 2,383 subjects, each noted a significant decrease in the VAS score with use of lubrication. Pooling all studies, the VAS score with lubrication changed -0.87 (95% CI = -1.22 to -0.53, 6 studies, 2,453 subjects). Studies measured discomfort at different points in the examination and noted significant decreases with insertion (mean difference, -0.98; 95% CI = -1.13 to -0.83, 5 studies, 2,383 subjects), opening (mean difference, -1.52; 95% CI = -2.43 to -0.61, 3 studies, 1,864 subjects), and extraction (mean difference, -0.97; 95% CI = -1.29 to -0.65, 2 studies, 284 subjects). These significant decreases were consistent in subgroups of premenopausal, postmenopausal, gynecologic oncology, and radiation therapy patients. CONCLUSIONS: Water-based gel lubrication decreased discomfort for women undergoing a plastic speculum examination in all populations studied.

Dissociable effects of social context on song and doublecortin immunoreactivity in male canaries.

Variation in environmental factors such as day length and social context greatly affects reproductive behavior and the brain areas that regulate these behaviors. One such behavior is song in songbirds, which males use to attract a mate during the breeding season. In these species the absence of a potential mate leads to an increase in the number of songs produced, while the presence of a mate greatly diminishes singing. Interestingly, although long days promote song behavior, producing song itself can promote the incorporation of new neurons in brain regions controlling song output. Social context can also affect such neuroplasticity in these song control nuclei. The goal of the present study was to investigate in canaries (Serinus canaria), a songbird species, how photoperiod and social context affect song and the incorporation of new neurons, as measured by the microtubule-associated protein doublecortin (DCX) in HVC, a key vocal production brain region of the song control system. We show that long days increased HVC size and singing activity. In addition, male canaries paired with a female for 2 weeks showed enhanced DCX-immunoreactivity in HVC relative to birds housed alone. Strikingly, however, paired males sang fewer songs that exhibited a reduction in acoustic features such as song complexity and energy, compared with birds housed alone, which sang prolifically. These results show that social presence plays a significant role in the regulation of neural and behavioral plasticity in songbirds and can exert these effects in opposition to what might be expected based on activity-induced neurogenesis.