Interneuron precursor transplants in adult hippocampus reverse psychosis-relevant features in a mouse model of hippocampal disinhibition

GABAergic interneuron hypofunction is hypothesized to underlie hippocampal dysfunction in schizophrenia. Here, we use the cyclin D2 knockout (Ccnd2^−/−) mouse model to test potential links between hippocampal interneuron deficits and psychosis-relevant neurobehavioral phenotypes. Ccnd2^−/− mice show cortical PV⁺ interneuron reductions, prominently in hippocampus, associated with deficits in synaptic inhibition, increased in vivo spike activity of projection neurons, and increased in vivo basal metabolic activity (assessed with fMRI) in hippocampus. Ccnd2^−/− mice show several neurophysiological and behavioral phenotypes that would be predicted to be produced by hippocampal disinhibition, including increased ventral tegmental area dopamine neuron population activity, behavioral hyperresponsiveness to amphetamine, and impairments in hippocampus-dependent cognition. Remarkably, transplantation of cells from the embryonic medial ganglionic eminence (the major origin of cerebral cortical interneurons) into the adult Ccnd2^−/− caudoventral hippocampus reverses these psychosis-relevant phenotypes. Surviving neurons from these transplants are 97% GABAergic and widely distributed within the hippocampus. Up to 6 mo after the transplants, in vivo hippocampal metabolic activity is lowered, context-dependent learning and memory is improved, and dopamine neuron activity and the behavioral response to amphetamine are normalized. These findings establish functional links between hippocampal GABA interneuron deficits and psychosis-relevant dopaminergic and cognitive phenotypes, and support a rationale for targeting limbic cortical interneuron function in the prevention and treatment of schizophrenia.Precursors of most γ-aminobutyric acid (GABA)-releasing interneurons of the cerebral cortex and the hippocampus originate in the embryonic medial ganglionic eminence (MGE) (1–3). A subpopulation of MGE-derived cells differentiates into fast-spiking, parvalbumin-expressing (PV⁺) interneurons that tightly regulate the activity and synchronization of cortical projection neurons (2, 4). Structural and functional deficits in PV⁺ interneurons are hypothesized as a pathophysiological mechanism in schizophrenia and psychotic disorders (4–6).Although psychotic disorders are clearly heterogeneous in etiology, disinhibition within temporolimbic cortical circuits is postulated as a core pathophysiology underlying positive symptoms (e.g., delusions and hallucinations) and a subset of cognitive disturbances that manifest with psychosis (4, 5, 7). Postmortem studies of brains from individuals with psychotic disorders show reduced molecular markers of the number and/or function of PV⁺ interneurons in the hippocampus (6, 8). Consistent with these observations, basal metabolic activity in the hippocampus, as measured with functional magnetic resonance imaging (fMRI), is increased in schizophrenia, a phenotype that predicts psychosis and positive symptom severity (5, 7). This abnormal resting activity is postulated to underlie abnormal recruitment of hippocampal circuits during cognitive performance (5, 9). Striatal dopamine (DA) release capacity is also increased and correlated with positive symptoms in schizophrenia and its risk states (10, 11). Importantly, hippocampal hyperactivity may contribute to DA dysregulation (12), because rodent studies show that caudoventral hippocampal (in the primate, anterior hippocampal) efferents regulate the activity of DA neurons and medial striatal DA release (13, 14).Thus, converging evidence implicates hippocampal disinhibition in the abnormal striatal DA transmission and cognitive impairment in schizophrenia. However, the role of hippocampal inhibitory interneurons in psychosis-relevant circuitry remains to be established. To this end, we used the cyclin D2 (Ccnd2) knockout mouse model (15), which displays a relatively selective deficit in cortical PV⁺ interneurons, and transplantation of interneuron precursors from the MGE to elucidate relationships between reduced hippocampal GABA interneuron function and multiple psychosis-relevant phenotypes, and to explore a novel treatment strategy for psychosis.     

A systematic review and meta-analysis of 130,000 individuals shows smoking does not modify the association of APOE genotype on risk of coronary heart disease

Background

Conflicting evidence exists on whether smoking acts as an effect modifier of the association between APOE genotype and risk of coronary heart disease (CHD).

Methods and results

We searched PubMed and EMBASE to June 11, 2013 for published studies reporting APOE genotype, smoking status and CHD events and added unpublished data from population cohorts. We tested for presence of effect modification by smoking status in the relationship between APOE genotype and risk of CHD using likelihood ratio test.In total 13 studies (including unpublished data from eight cohorts) with 10,134 CHD events in 130,004 individuals of European descent were identified. The odds ratio (OR) for CHD risk from APOE genotype (ε4 carriers versus non-carriers) was 1.06 (95% confidence interval (CI): 1.01, 1.12) and for smoking (present vs. past/never smokers) was OR 2.05 (95%CI: 1.95, 2.14). When the association between APOE genotype and CHD was stratified by smoking status, compared to non-ε4 carriers, ε4 carriers had an OR of 1.11 (95%CI: 1.02, 1.21) in 28,789 present smokers and an OR of 1.04 (95%CI 0.98, 1.10) in 101,215 previous/never smokers, with no evidence of effect modification (P-value for heterogeneity = 0.19). Analysis of pack years in individual participant data of >60,000 with adjustment for cardiovascular traits also failed to identify evidence of effect modification.

Conclusions

In the largest analysis to date, we identified no evidence for effect modification by smoking status in the association between APOE genotype and risk of CHD.     

Choroidal plasmacytoma in a patient with multiple myeloma. Diagnosis by fine-needle aspiration biopsy

BACKGROUND: To report a case of a secondary plasmacytoma of the choroid. METHODS: Interventional case report with cytopathologic correlation. RESULTS: A 61-year-old male with a breast nodule and a 2-year history of multiple myeloma developed blurred vision and was found to have three confluent, ill-defined areas of choroidal thickening in the left eye. Cytopathology and immunohistochemistry of a transocular fine-needle aspiration biopsy of the largest lesion revealed atypical plasma cells diagnostic of plasmacytoma. Following external beam radiotherapy the choroidal tumors resolved completely. CONCLUSION: Secondary plasmacytoma, despite its rarity, should be included in the differential diagnosis of amelanotic choroidal tumors, particularly in patients with multiple myeloma. Radiotherapy is an effective treatment.     

Effects of low-dose oral contraceptives on sugar metabolism

The effects on carbohydrate metabolism by four low-dose oral contraceptives were evaluated in four low-dose oral contraceptives were evaluated-66 young women randomly divided in four groups. In the various preparations there were a different dosage of estrogen (ethinylestradiol) together different doses and types of progestogen (desogestrel, gestodene, cyproterone acetate). After six months of treatment, in all groups a slight increase of glycemic and insulinemic responses during OGTT was observed; the significance was achieved with the preparation containing cyproterone acetate alone. Glycated hemoglobin did not change. Our results suggest that these new low-dose oral contraceptives induced negligible metabolic side effects.     

Ultrasound monitoring of testis and prostate maturation in hypogonadotropic hypogonadic males during gonadotropin-releasing hormone treatment

The effects of the administration of gonadotropin-releasing hormone (GnRH) on the increase of testis and prostate volume was monitored by ultrasound in six patients affected by idiopathic hypogonadotropic hypogonadism. A significant increase of testis volume was observed after 90 and 180 days (6.65 versus 3.32 mL, 99.1% net increase and 8.47 mL, 176.8% increase, respectively) of pulsatile GnRH treatment. A similar increase of prostate volume was observed at day 90 (12.67 versus 7.78 mL, 70.3% net increase) and day 180 (14.70 mL, 97.7% increase). The ultrasound monitoring of the modifications of testis and prostate volume may represent a biological assay of the effects of GnRH treatment and offer additional data on the response of target organs to the hormonal treatment.     

Evidence of specific benzodiazepine binding to myometrial membrane preparations from human pregnant uterus

The muscle relaxant effect of benzodiazepines (BDZ) is widely held to be mediated at central as well as at peripheral level. In this study we report that crude membrane preparations from the myometrium of pregnant women possess binding sites for [3H]-RO 5-4864, specific ligand for the peripheral type of BDZ receptor. Scatchard analysis shows a high affinity binding site (KD = 3.1 +/- 1.2 nM) and a class of low affinity binding sites (KD greater than 30 nM). Displacement experiments show that various BDZ are differently effective in inhibiting [3H]-RO 5-4864 binding: RO 5-4864 greater than diazepam greater than flunitrazepam greater than lorazepam greater than chlordiazepoxide. In conclusion, these data seem to demonstrate that human myometrium possesses specific binding sites of 'peripheral type' for BDZ. It may be suggested that these binding sites are involved in mediating the myometrial relaxant effect exerted by BDZ. Thus, peripherally active BDZ could be used as tocolytic agents, avoiding BDZ central effects.     

Effects of the dopamine antagonist veralipride on hot flushes and luteinizing hormone secretion in postmenopausal women

The effects on hot flushes of the dopamine antagonist Veralipride versus placebo were investigated in a randomized double-blind study of postmenopausal healthy women (N = 20 in each group). Cutaneous temperature recording and plasma LH pulsatility were studied in eight patients from each group. Veralipride administration (100 mg/day for 30 days) induced a significant (P less than .01) reduction in vasomotor symptoms and was more effective (P less than .05) than placebo. Treatment was followed by the expected increase (P less than .001) in plasma prolactin levels and by a significant decrease (P less than .05) in mean plasma LH. A significant reduction (P less than .01) was observed in objectively recorded hot flushes after Veralipride treatment, whereas there was no significant change in the characteristics of LH pulsatility. Infusion of the opioid antagonist naloxone (N = 5) induced a significant (P less than .01) increase in LH secretion after Veralipride administration. These results suggest that the endogenous opioid system may mediate the endocrine and clinical effects of long-term Veralipride treatment.     

Prevalence of bruxism awareness in a Sardinian population

1014 subjects on the island of Sardinia (Italy) were interviewed regarding the habit of clenching and grinding their teeth. They had to specify if this activity occurred during the day, during the night, or both. Other information recorded was their age, gender, marital status, and occupation. Overall prevalence of bruxism was 27.2% (276 subjects). No association was found between bruxism and age, gender and job. Even differentiating diurnal, nocturnal, diurnal and nocturnal bruxism, associations were non-significant. Marital status seems to make some difference: divorced people reported higher parafunctional activity compared to widows and widowers who reported the least. Although awareness of bruxism is not a precise measure of parafunction, based on the results we cannot support the role of stress on bruxism etiology.