Hippocampus-dependent cognitive enhancement induced by systemic gintonin administration

Background

A number of neurological and neurodegenerative diseases share impaired cognition as a common symptom. Therefore, the development of clinically applicable therapies to enhance cognition has yielded significant interest. Previously, we have shown that activation of lysophosphatidic acid receptors (LPARs) via gintonin application potentiates synaptic transmission by the blockade of K⁺ channels in the mature hippocampus. However, whether gintonin may exert any beneficial impact directly on cognition at the neural circuitry level and the behavioral level has not been investigated.

Methods

In the current study, we took advantage of gintonin, a novel LPAR agonist, to investigate the effect of gintonin-mediated LPAR activation on cognitive performances. Hippocampus-dependent fear memory test, synaptic plasticity in the hippocampal brain slices, and quantitative analysis on synaptic plasticity-related proteins were used.

Results

Daily oral administration of gintonin for 1 wk significantly improved fear memory retention in the contextual fear-conditioning test in mice. We also found that oral administration of gintonin for 1 wk increased the expression of learning and memory-related proteins such as phosphorylated cyclic adenosine monophosphate-response element binding (CREB) protein and brain-derived neurotrophic factor (BDNF). In addition, prolonged gintonin administration enhanced long-term potentiation in the hippocampus.

Conclusion

Our observations suggest that the systemic gintonin administration could successfully improve contextual memory formation at the molecular and synaptic levels as well as the behavioral level. Therefore, oral administration of gintonin may serve as an effective noninvasive, nonsurgical method of enhancing cognitive functions.

Synaptic enhancement induced by gintonin via lysophosphatidic acid receptor activation in central synapses

Lysophosphatidic acid (LPA) is one of the well-characterized, ubiquitous phospholipid molecules. LPA exerts its effect by activating G protein-coupled receptors known as LPA receptors (LPARs). So far, LPAR signaling has been critically implicated during early development stages, including the regulation of synapse formation and the morphology of cortical and hippocampal neurons. In adult brains, LPARs seem to participate in cognitive as well as emotional learning and memory. Recent studies using LPAR1-deficient mice reported impaired performances in a number of behavioral tasks, including the hippocampus-dependent spatial memory and fear conditioning tests. Nevertheless, the effect of LPAR activation in the synaptic transmission of central synapses after the completion of embryonic development has not been investigated. In this study, we took advantage of a novel extracellular agonist for LPARs called gintonin to activate LPARs in adult brain systems. Gintonin, a recently identified active ingredient in ginseng, has been shown to activate LPARs and mobilize Ca2+ in an artificial cell system. We found that the activation of LPARs by application of gintonin acutely enhanced both excitatory and inhibitory transmission in central synapses, albeit through tentatively distinct mechanisms. Gintonin-mediated LPAR activation primarily resulted in synaptic enhancement and an increase in neuronal excitability in a phospholipase C-dependent manner. Our findings suggest that LPARs are able to directly potentiate synaptic transmission in central synapses when stimulated exogenously. Therefore, LPARs could serve as a useful target to modulate synaptic activity under pathological conditions, including neurodegenerative diseases.

Chronic brain inflammation causes a reduction in GluN2A and GluN2B subunits of NMDA receptors and an increase in the phosphorylation of mitogen-activated protein kinases in the hippocampus

Neuroinflammation plays a key role in the initiation and progression of neurodegeneration in Alzheimer’s disease (AD). Chronic neuroinflammation results in diminished synaptic plasticity and loss of GluN1 N-methyl-D-aspartate (NMDA) receptors in the hippocampus, leading to the cognitive deficits that are the most common symptoms of AD. Therefore, it is suggested that chronic inflammation may alter expression levels of GluN2A and GluN2B subunits of NMDA receptors and associated intracellular signalling. Chronic neuroinflammation was induced by chronic infusion of lipopolysaccharide (LPS) into the fourth ventricle in Fischer-344 rats. The status of hippocampus-dependent memory was evaluated in control rats and rats chronically infused with LPS. Microglial activation in the hippocampus was examined using immunohistochemical staining. Western blot analysis was used to measure membrane levels of GluN2A and GluN2B subunits of NMDA receptors and mitogen-activated protein kinase (MAPK) in the hippocampi of these rats, and immunofluorescent double labeling was used to assess the cellular location of MAPK. Microglial activation was observed in the hippocampi of rats that showed memory impairments with chronic LPS infusion. Chronic LPS infusion reduced the levels of GluN2A and GluN2B and increased the levels of phosphorylated MAPKs in the hippocampus. MAPK-positive immunoreactivity was observed mostly in the neurons and also in non-neuronal cells. Reductions in GluN2A and GluN2B subunits of NMDA receptors coupled with altered MAPK signaling, in response to inflammatory stimuli may be related to the cognitive deficits observed in AD.

Rituximab versus an alternative TNF inhibitor in patients with rheumatoid arthritis who failed to respond to a single previous TNF inhibitor: SWITCH-RA, a global, observational, comparative effectiveness study

Objectives

To compare the effectiveness of rituximab versus an alternative tumour necrosis factor (TNF) inhibitor (TNFi) in patients with rheumatoid arthritis (RA) with an inadequate response to one previous TNFi.

Methods

SWITCH-RA was a prospective, global, observational, real-life study. Patients non-responsive or intolerant to a single TNFi were enrolled ≤4 weeks after starting rituximab or a second TNFi. Primary end point: change in Disease Activity Score in 28 joints excluding patient's global health component (DAS28-3)–erythrocyte sedimentation rate (ESR) over 6 months.

Results

604 patients received rituximab, and 507 an alternative TNFi as second biological therapy. Reasons for discontinuing the first TNFi were inefficacy (n=827), intolerance (n=263) and other (n=21). A total of 728 patients were available for primary end point analysis (rituximab n=405; TNFi n=323). Baseline mean (SD) DAS28-3–ESR was higher in the rituximab than the TNFi group: 5.2 (1.2) vs 4.8 (1.3); p<0.0001. Least squares mean (SE) change in DAS28-3–ESR at 6 months was significantly greater in rituximab than TNFi patients: −1.5 (0.2) vs −1.1 (0.2); p=0.007. The difference remained significant among patients discontinuing the initial TNFi because of inefficacy (−1.7 vs −1.3; p=0.017) but not intolerance (−0.7 vs −0.7; p=0.894). Seropositive patients showed significantly greater improvements in DAS28-3–ESR with rituximab than with TNFi (−1.6 (0.3) vs −1.2 (0.3); p=0.011), particularly those switching because of inefficacy (−1.9 (0.3) vs −1.5 (0.4); p=0.021). The overall incidence of adverse events was similar between the rituximab and TNFi groups.

Conclusions

These real-life data indicate that, after discontinuation of an initial TNFi, switching to rituximab is associated with significantly improved clinical effectiveness compared with switching to a second TNFi. This difference was particularly evident in seropositive patients and in those switched because of inefficacy.

Abstract P5-14-15: Discovery and validation of simple heart measurements to screen patients who will benefit from deep inspiration breath hold for left breast irradiation

Purpose:

Deep inspiration breath hold (DIBH) using active breath control in left-sided breast irradiation (RT) can significantly reduce radiation dose to heart and coronary arteries in selected patients. At our institution, a cutoff of V50% &gt;10cc is currently used to identify patients who require DIBH. This dose-volume cutoff requires generation of a radiation plan in order to select patients. The purpose of this study was to identify simple 2-D measurements of the heart at the time of CT simulation that can help screen patients for DIBH in order to streamline the process for left-sided breast RT.

Methods:

This study evaluated CT simulation scans from 50 left-sided breast cancer patients treated with tangent RT alone, where 50% of patients were treated with DIBH. On each CT dataset, a tangential line was drawn between the medial and lateral tattoos. The following heart measurements were recorded by a blinded observer at 2, 3, 4, and 5 cm below the tattoos: (1) maximal heart distance (MHD) perpendicular to this line and (2) heart length (HL) along this line. Predictive models were created using two strategies; (1) step wise approach utilizing the most significant factor and (2) principle component analysis. Using C-statistics, 3 cutoffs with the highest correlations with heart dose were determined from the model. These cutoffs were validated in a cohort of 100 consecutive patients treated from Jan-May 2012.

Results:

Data from 49 patients in the derivation cohort were analyzable. The HL at 2 cm had the strongest correlation with V50 (R2 = 0.45; p &lt;0.0001). Other values that were associated with V50 were HL at 3 cm (R2 = 0.37; p = &lt;0.0001), MHD at 2cm (R2 = 0.25; p = 0.0003), MHD at 3 cm (R2 = 0.23; p = 0.0006) and HL at 4 cm (R2 = 0.17, p = 0.0035). The predictive model using HL at 2 cm gave an adjusted R2 = 0.4385 (P&lt;0.0001). Adding other variables into the predictive model did not improve the adjusted R2. The following 3 cutoffs for HL at 2 cm with respective (sensitivity; specificity) were identified: 3.92 cm (0.955; 0.48), 7.65 cm (0.32; 0.48), and 6.5 cm (0.5; 0.8). In the validation cohort, 22/100 had V50% &gt; 10 cc. Validation of the 3 derived cutoffs for HL at 2 cm yielded the following sensitivities and specificities: 1.0 and 0.28 for 3.92 cm; 0.53 and 0.93 for 7.65 cm; 0.58 and 0.69 for 6.5 cm. Positive predictive value (PPV) and negative predictive value (NPV) were as follows: 3.92 cm (PPV = 0.25; NPV = 1.00). 7.65 cm (PPV = 0.63; NPV = 0.89), and 6.5cm (PPV = 0.30; NPV = 0.87).

Conclusions:

A simple 2-D heart measurement, heart length at 2 cm below the tattoos, had moderate correlation with the irradiated heart volume. Although HL at 2 cm did not have both high specificity and sensitivity to predict who would benefit from DIBH, cut-offs could be selected to maximize sensitivity (3.92 cm for sensitivity 1.0) or specificity (7.65 cm for specificity 0.93). For example, in departments that routinely acquire both free-breathing and DIBH CT simulation scans for all left-sided patients, a cutoff of 3.92cm would minimize the number of unnecessary DIBH scans.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-14-15.

Abstract P1-13-14: Discordance of ER and PR status between primary and recurrent breast cancer in association with endocrine therapy

Background: Discordance in tumor receptor status between primary and recurrent tumors has been previously reported. Discordant ER/PR status has been used to differentiate recurrences from new primaries. We evaluated discordance rates of ER and PR expression between the primary and locoregional/contralateral recurrences and examined the relationship with adjuvant endocrine therapy (ET).

Methods: We conducted a retrospective chart review of breast cancer patients (pts) treated with lumpectomy and adjuvant locoregional radiation (RT) from 1999-2005 at the Princess Margaret Cancer Centre. Tumor recurrence was classified as locoregional recurrence (LRR) for ipsilateral breast or lymph node recurrence, contralateral disease (CD) or distant recurrence. ER and PR were assessed by immunohistochemistry; positive if &gt;10% tumor cells staining, borderline if 10% staining, and negative if &lt;10% staining. Univariate analyses were applied to determine the association of receptor discordance with age, menopausal status, tumor grade, endocrine therapy or adjuvant chemotherapy.

Results: All 441 pts had a lumpectomy with negative margins and RT, and had a median follow-up of 8.3 years. The median age at primary surgery was 57, and 67% of pts were postmenopausal. ET (tamoxifen and/or aromatase inhibitors) was initiated in 294 (84%) eligible patients. There were 24 (5.4%) pts with LRR, 20 (4.5%) pts with CD, and 28 (6.3%) with distant metastases. Nine pts with LRR also had distant disease, and 3 pts with CD also had distant disease. Among pts with LRR, 17 had ER/PR status available for comparison. Discordance rates for ER and PR were (1/17) 5.9% and (3/17) 17.6%, respectively, and the most common change was ER becoming positive, and PR becoming negative (75%). For pts with CD, 18 had ER/PR status available for comparison. Discordance rates for ER and PR were (7/18) 38.9% and (9/18) 50%, respectively. The most common change was ER becoming positive (86%), and PR becoming positive (75%). Distant disease receptor status was only available for two patients, therefore not included. The patient with LRR and discordant ER did not receive ET, while pts with LRR and discordant PR all received ET. Among patients with CD, 15% of patients with discordant ER status received ET, and 33% with discordant PR received ET. There was no statistically significant association between discordance rates in either LRR or CD groups and use of ET. Similarly, discordance rates were not associated with the other patient or tumor variables studied, or the development of distant metastases or death.

Conclusions: Discordance of ER and PR expression was low in LRR and higher in CD, where the majority of changes were from negative to positive receptor status. Receptor discordance was not associated with endocrine therapy. This study suggests that the biology of LRR and CD may be different, and re-evaluation of receptor status could lead to additional treatment options becoming available from an endocrine standpoint.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-13-14.

Abstract P2-02-10: Evaluation of apparent diffusion coefficient to predict grade, micro-invasion and invasion in DCIS

PURPOSE: To evaluate the role of apparent diffusion coefficient (ADC) values in distinguishing DCIS grades and identifying the presence of micro-invasive/invasive disease.

METHODS AND MATERIALS:

REB approved study with informed consent obtained from 70 women (age 36-84) scheduled for core-biopsy with results of 71 non-invasive/high-risk breast lesions. All patients underwent surgery and were assessed pre-operatively using diffusion weighted (DWI)-MRI. Lesion size, morphology and ADC values were recorded. The Kruskal Wallis or one-way ANOVA test and Pearson correlation coefficient were used to study the association between ADC values and the analyzed MRI lesion characteristics. Logistic regression analysis was used to evaluate the ability of ADC values to predict the presence of invasion.

RESULTS:

Of 71 cases, 45.1% were imaged on a 3T magnet and 54.9% on 1.5 T. Final pathology demonstrated invasive cancer in 26.8%, micro-invasion in 18.3% and pure DCIS in 59.2%. On 3T, mean ADC value was 1.20 ×10-3 mm2/s ± 0.48 (SD) (range, 0.47 - 1.78 ×10-3 mm2/s) for non-high grade DCIS, 1.23 × 10-3 mm2/s ± 0.40 (SD) (range, 0.26 - 1.77 ×10-3 mm2/s) for high-grade DCIS, and 1.15 × 10-3 mm2/s ± 0.45 (SD) (range, 0.26 - 1.75 ×10-3 mm2/s) for invasive/microinvasive disease. On 1.5T, mean ADC value was 1.04 × 10-3 mm2/s ± 0.41 (SD) (range, 0.15 - 1.85 ×10-3 mm2/s) for non-high grade DCIS, 1.01 × 10-3 mm2/s ± 0.37 (SD) (range, 0.06 - 1.76 ×10-3 mm2/s) for high-grade DCIS, and 1.11 × 10-3 mm2/s ± 0.30 (SD) (range, 0.64 - 1.76 ×10-3 mm2/s) for invasive/microinvasive disease. Based on logistic regression analysis, mean ADC value was not a significant predictor for invasiveness using 1.5 T [OR = 2.6 (95% CI (0.409, 17.12)), p = 0.3] or 3T [OR = 0.4 (95% CI (0.076, 2.399)), p = 0.3]

CONCLUSION: Mean ADC acquired using a 1.5T or 3T MRI was unable to predict high-grade or invasive disease in biopsy-proven DCIS lesions. Further work is exploring voxel-based approaches that may better appreciate tumor heterogeneity and identify sub-regions of tumor with these higher risk features.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-02-10.