Interrelationship of Primary Virus Replication, Level of Latency, and Time to Reactivation in the Trigeminal Ganglia of Latently Infected Mice.

UNLABELLED: We sought to determine the possibility of an interrelationship between primary virus replication in the eye, the level of viral DNA in the trigeminal ganglia (TG) during latency, and the amount of virus reactivation following ocular herpes simplex virus type 1 (HSV-1) infection. Mice were infected with virulent (McKrae) or avirulent (KOS and RE) strains of HSV-1, and virus titers in the eyes and TG during primary infection, level of viral gB DNA in TG on day 28 postinfection (p.i.), and virus reactivation on day 28 p.i. as measured by explant reactivation were calculated. Our results suggest that the avirulent strains of HSV-1, even after corneal scarification, had lower virus titers in the eye, had less latency in the TG, and took a longer time to reactivate than virulent strains of HSV-1. The time to explant reactivation of avirulent strains of HSV-1 was similar to that of the virulent LAT((-)) McKrae-derived mutant. The viral dose with the McKrae strain of HSV-1 affected the level of viral DNA and time to explant reactivation. Overall, our results suggest that there is no absolute correlation between primary virus titer in the eye and TG and the level of viral DNA in latent TG and time to reactivation. IMPORTANCE: Very little is known regarding the interrelationship between primary virus replication in the eye, the level of latency in TG, and the time to reactivate in the mouse model. This study was designed to answer these questions. Our results point to the absence of any correlation between the level of primary virus replication and the level of viral DNA during latency, and neither was an indicator of how rapidly the virus reactivated following explant TG-induced reactivation.

Decreased neonatal jaundice readmission rate after implementing hyperbilirubinemia guidelines and universal screening for bilirubin.

Readmission rate for neonatal jaundice approximate 10 per 1000 live births. After applying hyperbilirubinemia guidelines and universal screening for bilirubin in term and near-term newborns, the readmission rate declined significantly from 24 to 3.7 per 1000 live births. Decreased readmission rate for neonatal jaundice may reduce kernicterus rate and health care costs. Further studies are necessary to explore these potential benefits.

Level of herpes simplex virus type 1 latency correlates with severity of corneal scarring and exhaustion of CD8+ T cells in trigeminal ganglia of latently infected mice.

A hallmark of infection with herpes simplex virus type 1 (HSV-1) is the establishment of latency in ganglia of the infected individual. During the life of the latently infected individual, the virus can occasionally reactivate, travel back to the eye, and cause recurrent disease. Indeed, a major cause of corneal scarring (CS) is the scarring induced by HSV-1 following reactivation from latency. In this study, we evaluated the relationship between the amount of CS and the level of the HSV-1 latency-associated transcript (LAT) in trigeminal ganglia (TG) of latently infected mice. Our results suggested that the amount of CS was not related to the amount of virus replication following primary ocular HSV-1 infection, since replication in the eyes was similar in mice that did not develop CS, mice that developed CS in just one eye, and mice that developed CS in both eyes. In contrast, mice with no CS had significantly less LAT, and thus presumably less latency, in their TG than mice that had CS in both eyes. Higher CS also correlated with higher levels of mRNAs for PD-1, CD4, CD8, F4/80, interleukin-4, gamma interferon, granzyme A, and granzyme B in both cornea and TG. These results suggest that (i) the immunopathology induced by HSV-1 infection does not correlate with primary virus replication in the eye; (ii) increased CS appears to correlate with increased latency in the TG, although the possible cause-and-effect relationship is not known; and (iii) increased latency in mouse TG correlates with higher levels of PD-1 mRNA, suggesting exhaustion of CD8+ T cells.

Flt3L in combination with HSV1-TK-mediated gene therapy reverses brain tumor-induced behavioral deficits.

Glioblastoma multiforme (GBM) is an invasive and aggressive primary brain tumor which is associated with a dismal prognosis. We have earlier developed a macroscopic, intracranial, syngeneic GBM model, in which treatment with adenoviral vectors (Ads) expressing herpes simplex virus type 1 thymidine kinase (HSV1-TK) plus ganciclovir (GCV) resulted in survival of approximately 20% of the animals. In this model, treatment with Ads expressing Fms-like tyrosine kinase 3 ligand (Flt3L), in combination with Ad-HSV1-TK improves the survival rate to approximately 70% and induces systemic antitumor immunity. We hypothesized that the growth of a large intracranial tumor mass would cause behavioral abnormalities that can be reversed by the combined gene therapy. We assessed the behavior and neuropathology of tumor-bearing animals treated with the combined gene therapy, 3 days after treatment, in long-term survivors, and in a recurrent model of glioma. We demonstrate that the intracranial GBM induces behavioral deficits that are resolved after treatment with Ad-Flt3L/Ad-TK (+GCV). Neuropathological analysis of long-term survivors revealed an overall recovery of normal brain architecture. The lack of long-term behavioral deficits and limited neuropathological abnormalities demonstrate the efficacy and safety of the combined Ad-Flt3L/Ad-TK gene therapy for GBM. These findings can serve to underpin further developments of this therapeutic modality, leading toward implementation of a Phase I clinical trial.

Comparison of the effects of desmethylimipramine on behavior in the forced swim test in peripubertal and adult rats.

Although there are similarities in the clinical presentation of adolescent and adult depression, there are differences in the biological correlates and the responses to pharmacologic treatment. Selective serotonin reuptake inhibitor-type antidepressants are efficacious, but tricyclic antidepressants have no or limited efficacy in treating adolescent patients. The forced swim test (FST) is a widely accepted animal model used to screen drugs for antidepressant activity. It is not known whether tricyclic antidepressants produce differential effects in peripubertal and adult rats, as is found in adolescent and adult humans. The objective of the study was to test the hypothesis that the tricyclic antidepressant desmethylimipramine (DMI) would show efficacy in the FST in adult, but not in peripubertal, rats. Thirty-day-old (peripubertal) and 112-day-old (young adult) rats were pretreated with saline or DMI and subjected to the FST. DMI reduced the amount of floating behavior and increased the amount of climbing behavior in both peripubertal and adult rats. Thus, the tricyclic antidepressant DMI has antidepressant-like activity in peripubertal rats in the FST. Owing to the discrepancy between the preclinical and clinical data, the predictive validity of the FST might need to be reevaluated across different age groups.

Flt3L in Combination With HSV1-TK-mediated Gene Therapy Reverses Brain Tumor-induced Behavioral Deficits.

Glioblastoma multiforme (GBM) is an invasive and aggressive primary brain tumor which is associated with a dismal prognosis. We have earlier developed a macroscopic, intracranial, syngeneic GBM model, in which treatment with adenoviral vectors (Ads) expressing herpes simplex virus type 1 thymidine kinase (HSV1-TK) plus ganciclovir (GCV) resulted in survival of ∼20% of the animals. In this model, treatment with Ads expressing Fms-like tyrosine kinase 3 ligand (Flt3L), in combination with Ad-HSV1-TK improves the survival rate to ∼70% and induces systemic antitumor immunity. We hypothesized that the growth of a large intracranial tumor mass would cause behavioral abnormalities that can be reversed by the combined gene therapy. We assessed the behavior and neuropathology of tumor-bearing animals treated with the combined gene therapy, 3 days after treatment, in long-term survivors, and in a recurrent model of glioma. We demonstrate that the intracranial GBM induces behavioral deficits that are resolved after treatment with Ad-Flt3L/Ad-TK (+GCV). Neuropathological analysis of long-term survivors revealed an overall recovery of normal brain architecture. The lack of long-term behavioral deficits and limited neuropathological abnormalities demonstrate the efficacy and safety of the combined Ad-Flt3L/Ad-TK gene therapy for GBM. These findings can serve to underpin further developments of this therapeutic modality, leading toward implementation of a Phase I clinical trial.

Developmental exposure to corticosterone: behavioral changes and differential effects on leukemia inhibitory factor (LIF) and corticotropin-releasing hormone (CRH) gene expression in the mouse.

RATIONALE: Cytokines are found in both the peripheral and central nervous system. There has been increasing interest in their potential role in some of the behavioral features of depressive disorders. Leukemia inhibitory factor (LIF), a proinflammatory cytokine, produces stimulation of adrenocorticotropic hormone (ACTH) secretion in response to emotional and inflammatory stress and recently has been linked to depressive-type behavior. Both the hypothalamic-pituitary-adrenal axis and the immune system, including cytokine-mediated responses, appear to be susceptible to long-term programming during fetal and neonatal development. OBJECTIVE: The present study was designed to characterize the effects of perinatal exposure to corticostereone on behavior, hypothalamic LIF and corticotropin-releasing hormone (CRH) mRNA expression, and basal plasma corticosterone levels in adult female mice. METHODS: Corticosterone was added to the drinking water beginning the last week of gestation and continued until weaning. Behavior in the open field and forced swim tests, baseline plasma corticosterone levels, and hypothalamic LIF and CRH gene expression were evaluated in the adult offspring. RESULTS: Mice exposed to perinatal corticosterone showed increased immobility in the forced swim test and increased locomotor activity in the open field test. Although there were no differences between treatment groups in terms of basal plasma levels of corticosterone or hypothalamic CRH mRNA, LIF mRNA expression was increased in the hypothalamus. CONCLUSIONS: These results show that perinatal exposure to glucocorticoids can produce long-term behavioral changes and upregulation of central LIF mRNA expression.

The effects of celecoxib augmentation on cytokine levels in schizophrenia.

Celecoxib augmentation therapy has been reported to enhance the rate of clinical response for patients with schizophrenia. This may be due in part to an effect of celecoxib in the immune dysfunction associated with schizophrenia. Given concerns about the safety of COX-2 inhibitors, studies investigating cytokine levels in medicated patients with schizophrenia are of public health importance. Twenty-eight schizophrenia subjects stabilized on olanzapine or risperidone were randomized to receive 8 wk of celecoxib (400 mg/d) or placebo. Serum soluble IL-2 receptor (sIL-2r) and in-vitro PHA-stimulated whole-blood cytokine production levels were measured at baseline, 1 wk, and 8 wk. Celecoxib augmentation did not alter any of the cytokine parameters measured for the overall study group. However, 1 wk of celecoxib augmentation increased TNF-alpha and IL-2 production levels in olanzapine-treated subjects. These elevations did not persist by week 8. Overall, celecoxib does not significantly modify cytokine levels in medicated schizophrenia subjects.

The role of antagonism of NMDA receptor-mediated neurotransmission and inhibition of the dopamine reuptake in the neuroendocrine effects of phencyclidine.

Phencyclidine (PCP) activates the hypothalamo-pituitary-adrenal (HPA) axis and decreases plasma prolactin levels in the rat. PCP is a noncompetitive N-methyl-d-aspartate (NMDA) receptor antagonist, but it also inhibits the reuptake of dopamine, serotonin and norepinephrine. The purpose of the present study was to utilize the PCP analogue N-[1-(2-thienyl)cyclohexyl]piperidine; (TCP), the potent dopamine reuptake inhibitor N-[1-(2-benzo(b)thiophenyl) cyclohexyl]piperidine; (BTCP) and the nonselective monoamine reuptake inhibitor cocaine as pharmacologic probes in order to determine the roles of noncompetitive NMDA receptor blockade and inhibition of dopamine reuptake in the neuroendocrine effects of PCP. PCP, TCP and cocaine increased plasma levels of adrenocorticotropin and corticosterone, but BTCP had no effect. In contrast, PCP, BTCP and cocaine decreased plasma prolactin, but TCP produced no such effect. The data suggest that mechanisms besides inhibition of dopamine reuptake are involved in the effects of PCP on the HPA axis, and the PCP-induced decrease in plasma prolactin is not a consequence of inhibition of NMDA receptor-mediated neurotransmission.

Celecoxib augmentation of continuously ill patients with schizophrenia.

BACKGROUND: Previous reports have demonstrated a beneficial effect of celecoxib adjunctive therapy for patients with an acute exacerbation of schizophrenia. We investigated the effects of celecoxib augmentation of atypical antipsychotic medications for continuously symptomatic outpatient subjects with schizophrenia to further extend these findings. We hypothesized that celecoxib augmentation therapy would improve psychopathology ratings compared with placebo. METHODS: Thirty-eight symptomatic outpatient subjects meeting DSM-IV criteria for schizophrenia and on a stable dose of an atypical antipsychotic medication for at least three months were randomized to receive 8 weeks of double blind placebo or celecoxib (400 mg/day) augmentation. Measures of psychopathology, functional disability, and extrapyramidal side effects were performed throughout the study. RESULTS: The treatment cohorts did not differ on any of the clinical outcome measures. CONCLUSIONS: Celecoxib augmentation of continuously ill outpatient subjects with schizophrenia did not improve clinical symptoms or measures of disability.

Endotoxin exposure in utero increases ethanol consumption in adult male offspring.

Epidemiological studies have suggested that adverse experiences in utero predispose individuals to neurobehavioral disorders including drug abuse in adulthood. The present study was designed to examine the hypothesis that maternal endotoxin exposure during pregnancy increases ethanol consumption in adult offspring. Pregnant Sprague-Dawley rats were subjected to lippopolysaccharide (LPS, 1.0 mg/kg, s.c.) treatment on alternate days throughout pregnancy. Adult male offspring were tested for ethanol consumption by using a free-access and two bottle choice paradigm. The animals exposed to LPS showed increased ethanol intake and preference as well as decreased rearing activity in the open field test. These data suggest that maternal infection during pregnancy might precipitate alcohol drinking behavior in adult offspring and this effect might be due, at least in part, to elevated levels of anxiety.

Reduced immobility in the forced swim test in mice with a targeted deletion of the leukemia inhibitory factor (LIF) gene.

Cytokines are a large and diverse group of polypeptides that are rapidly released in response to tissue injury, infection, and inflammation. Besides their effects in the periphery, cytokines also affect the central nervous system (CNS). There has been increasing interest in the potential role of cytokines in the behavioral features of depressive disorders. One cytokine that might be a candidate for a role in the etiology of depression is leukemia inhibitory factor (LIF). LIF mRNA has been detected in the hypothalamus, hippocampus, amygdala, cerebellum, cerebral cortex, and basal forebrain nuclei. The role of LIF in the CNS has not been fully elucidated. Based upon the hypothesis that cytokines might have a role in depression, the present study characterized the behavior of mice with a targeted disruption of the LIF gene (LIF knockouts) in the forced swim test, an animal model used to measure depressive-like behavior and the response to antidepressants. It was found that LIF knockout mice show reduced immobility in the forced swim test, suggesting that LIF might have a potential role in the etiology of some forms of depression.