Brad D. Pearce

Cortisol Levels and Risk for Psychosis: Initial Findings from the North American Prodrome Longitudinal Study

BACKGROUND Studies of biomarkers of hypothalamic-pituitary-adrenal activity indicate that psychotic disorders are associated with elevated cortisol. This study examined cortisol levels in healthy control subjects and individuals who met clinical high-risk (CHR) criteria for psychosis. It was hypothesized that cortisol levels would be 1) elevated in the CHR group relative to control subjects, 2) positively correlated with symptom severity, and 3) most elevated in CHR patients who transition to psychotic level severity. METHODS Baseline assessments were conducted at eight centers in the North American Prodrome Longitudinal Study. The present CHR sample included 256 individuals meeting the Scale for Prodromal Symptoms criteria and 141 control subjects, all of whom underwent baseline assessment and measurement of salivary cortisol. RESULTS Consistent with previous reports, there was an effect of age on cortisol, with increases through the adolescent/early adult years. Analysis of covariance showed a main effect of diagnostic group, with the CHR group showing higher cortisol. There were modest, positive correlations of cortisol with baseline symptom severity, and analysis of covariance revealed higher baseline cortisol in those who transitioned to psychotic level symptoms when compared with healthy control subjects and CHR subjects who remitted. CONCLUSIONS The present findings add to accumulating evidence of heightened cortisol secretion in CHR individuals. The findings also indicate nonspecific associations between cortisol levels and symptom severity, as well as symptom progression. The role of hypothalamic-pituitary-adrenal activity in prediction of conversion to psychosis and its relation with other biomarkers of risk should receive attention in future research.

Dynamic Regulation of T Cell Immunity by CD43

During a viral response, Ag-specific effector T cells show dramatically increased binding by the mAb 1B11 and the lectin peanut agglutinin (PNA). We investigated the contribution of CD43 expression to 1B11 and PNA binding as well as its role in generation and maintenance of a CD8 T cell response. Analysis of CD43−/− mice revealed no increased 1B11 binding and reduced PNA binding on virus-specific CD8 T cells from −/− mice compared with +/+ mice. Furthermore, we examined the role of CD43 in the kinetics of an immune response. We show that CD43 expression modestly effects generation of a primary virus-specific CD8 T cell response in vivo but plays a more significant role in trafficking of CD8 T cells to tissues such as the brain. More interestingly, CD43 plays a role in the contraction of the immune response, with CD43−/− mice showing increased numbers of Ag-specific CD8 T cells following initial expansion. Following the peak of expansion, Ag-specific CD8 T cells from −/− mice show similar proliferation but demonstrate increased Bcl-2 levels and decreased apoptosis of Ag-specific effector CD8 T cells in vitro. Consistent with a delay in the down-modulation of the immune response, following chronic viral infection CD43−/− mice show increased morbidity. These data suggest a dynamic role of CD43 during an immune response: a positive regulatory role in costimulation and trafficking of T cells to the CNS and a negative regulatory role in the down-modulation of an immune response.

Longitudinal changes in cortisol secretion and conversion to psychosis in at-risk youth.

Elevations in hypothalamic-pituitary-adrenal (HPA) axis activity have been implicated in the origins and exacerbation of mental disorders. Several lines of investigation suggest HPA activity, indexed by increased cortisol, is elevated in patients with schizophrenia and other psychotic disorders. This study examined the relation of cortisol levels and longitudinal changes with psychotic outcomes in at-risk adolescents. Participants were 56 adolescents who met risk criteria for psychosis, namely, schizotypal personality disorder (n = 5), prodromal symptom criteria based on the Structured Interview for Prodromal Symptoms (n = 17), or both (n = 34). Of these, 14 subsequently met DSM-IV criteria for an Axis I psychotic disorder (schizophrenia, schizoaffective disorder, or mood disorder with psychotic features). Participants were assessed at baseline and then followed longitudinally. Salivary cortisol was sampled multiple times at initial assessment, interim follow-up, and 1-year follow-up. Area under the curve (AUC) was computed from the repeated cortisol measures. The findings indicate that at-risk subjects who subsequently developed psychosis showed significantly higher cortisol at the first follow-up, a trend at the 1-year follow-up, and a significantly larger AUC when compared to those who did not convert. A similar pattern of group differences emerged from analyses excluding those who may have converted prior to the 1-year follow-up. These findings converge with previous reports on HPA activity in psychosis, as well as theoretical assumptions concerning the effects of cortisol elevations on brain systems involved in psychotic symptoms. Future research with larger samples is needed to confirm and extend these results.

Archival ReportThe Relationship Between Toxoplasma Gondii Infection and Mood Disorders in the Third National Health and Nutrition Survey

BACKGROUND Toxoplasma gondii (T. gondii) is a neurotropic protozoan parasite that causes persistent infection in humans. A substantial literature suggests that schizophrenia is associated with increased seroprevalence of T. gondii, but a possible link of the parasite with mood disorders has not been as thoroughly investigated. METHODS We examined the association of Toxoplasma-specific immunoglobulin G results with mood disorder outcomes in 7440 respondents from the third National Health and Nutrition Survey, which is a nationally representative sample of the United States noninstitutionalized civilian population. Regression models were adjusted for numerous potential confounders, including tobacco smoking and C-reactive protein levels. RESULTS No statistically significant associations were found between T. gondii seroprevalence and a history of major depression (n = 574; adjusted odds ratio [OR]: .8; 95% confidence interval [CI]: .5-1.2), severe major depression (n = 515; adjusted OR: .8; 95% CI: .6-1.2), dysthymia (n = 548; adjusted OR: 1.1; 95% CI: .7-1.8), or dysthymia with comorbid major depression (n = 242, adjusted OR: 1.2; 95% CI: .6-2.4), all p values were > .05, including analysis stratified by gender. However, there was a significant relationship between T. gondii seroprevalence and bipolar disorder type I for respondents in which both manic and major depression symptoms were reported (n = 41; adjusted OR: 2.4; 95% CI: 1.2-4.8; p < .05). CONCLUSIONS In a population-based sample, T. gondii seroprevalence is not elevated in unipolar mood disorders but is higher in a subset of respondents with a history of bipolar disorder type 1.

Identification of fetal and maternal single nucleotide polymorphisms in candidate genes that predispose to spontaneous preterm labor with intact membranes

OBJECTIVE The purpose of this study was to determine whether maternal/fetal single nucleotide polymorphisms (SNPs) in candidate genes are associated with spontaneous preterm labor/delivery. STUDY DESIGN A genetic association study was conducted in 223 mothers and 179 fetuses (preterm labor with intact membranes who delivered <37 weeks of gestation [preterm birth (PTB)]), and 599 mothers and 628 fetuses (normal pregnancy); 190 candidate genes and 775 SNPs were studied. Single locus/haplotype association analyses were performed; the false discovery rate was used to correct for multiple testing. RESULTS The strongest single locus associations with PTB were interleukin-6 receptor 1 (fetus; P=.000148) and tissue inhibitor of metalloproteinase 2 (mother; P=.000197), which remained significant after correction for multiple comparisons. Global haplotype analysis indicated an association between a fetal DNA variant in insulin-like growth factor F2 and maternal alpha 3 type IV collagen isoform 1 (global, P=.004 and .007, respectively). CONCLUSION An SNP involved in controlling fetal inflammation (interleukin-6 receptor 1) and DNA variants in maternal genes encoding for proteins involved in extracellular matrix metabolism approximately doubled the risk of PTB.

A genetic association study of maternal and fetal candidate genes that predispose to preterm prelabor rupture of membranes (PROM).

OBJECTIVE We sought to determine whether maternal/fetal single-nucleotide polymorphisms (SNPs) in candidate genes are associated with preterm prelabor rupture of membranes (pPROM). STUDY DESIGN A case-control study was conducted in patients with pPROM (225 mothers and 155 fetuses) and 599 mothers and 628 fetuses with a normal pregnancy; 190 candidate genes and 775 SNPs were studied. Single locus/haplotype association analyses were performed; false discovery rate was used to correct for multiple testing (q* = 0.15). RESULTS First, a SNP in tissue inhibitor of metalloproteinase 2 in mothers was significantly associated with pPROM (odds ratio, 2.12; 95% confidence interval, 1.47-3.07; P = .000068), and this association remained significant after correction for multiple comparisons. Second, haplotypes for Alpha 3 type IV collagen isoform precursor in the mother were associated with pPROM (global P = .003). Third, multilocus analysis identified a 3-locus model, which included maternal SNPs in collagen type I alpha 2, defensin alpha 5 gene, and endothelin 1. CONCLUSION DNA variants in a maternal gene involved in extracellular matrix metabolism doubled the risk of pPROM.

Racial disparity in pathophysiologic pathways of preterm birth based on genetic variants

ObjectiveTo study pathophysiologic pathways in spontaneous preterm birth and possibly the racial disparity associating with maternal and fetal genetic variations, using bioinformatics tools.MethodsA large scale candidate gene association study was performed on 1442 SNPs in 130 genes in a case (preterm birth < 36 weeks) control study (term birth > 37 weeks). Both maternal and fetal DNA from Caucasians (172 cases and 198 controls) and 279 African-Americans (82 cases and 197 controls) were used. A single locus association (genotypic) analysis followed by hierarchical clustering was performed, where clustering was based on p values for significant associations within each race. Using Ingenuity Pathway Analysis (IPA) software, known pathophysiologic pathways in both races were determined.ResultsFrom all SNPs entered into the analysis, the IPA mapped genes to specific disease functions. Gene variants in Caucasians were implicated in disease functions shared with other known disorders; specifically, dermatopathy, inflammation, and hematological disorders. This may reflect abnormal cervical ripening and decidual hemorrhage. In African-Americans inflammatory pathways were the most prevalent. In Caucasians, maternal gene variants showed the most prominent role in disease functions, whereas in African Americans it was fetal variants. The IPA software was used to generate molecular interaction maps that differed between races and also between maternal and fetal genetic variants.ConclusionDifferences at the genetic level revealed distinct disease functions and operational pathways in African Americans and Caucasians in spontaneous preterm birth. Differences in maternal and fetal contributions in pregnancy outcome are also different between African Americans and Caucasians. These results present a set of explicit testable hypotheses regarding genetic associations with preterm birth in African Americans and Caucasians

Dysregulated biomarkers induce distinct pathways in preterm birth

Please cite this paper as: Brou L, Almli L, Pearce B, Bhat G, Drobek C, Fortunato S, Menon R. Dysregulated biomarkers induce distinct pathways in preterm birth. BJOG 2012;119:458–473.

Infection and Inflammation in Schizophrenia and Bipolar Disorder: A Genome Wide Study for Interactions with Genetic Variation

Inflammation and maternal or fetal infections have been suggested as risk factors for schizophrenia (SZ) and bipolar disorder (BP). It is likely that such environmental effects are contingent on genetic background. Here, in a genome-wide approach, we test the hypothesis that such exposures increase the risk for SZ and BP and that the increase is dependent on genetic variants. We use genome-wide genotype data, plasma IgG antibody measurements against Toxoplasma gondii, Herpes simplex virus type 1, Cytomegalovirus, Human Herpes Virus 6 and the food antigen gliadin as well as measurements of C-reactive protein (CRP), a peripheral marker of inflammation. The subjects are SZ cases, BP cases, parents of cases and screened controls. We look for higher levels of our immunity/infection variables and interactions between them and common genetic variation genome-wide. We find many of the antibody measurements higher in both disorders. While individual tests do not withstand correction for multiple comparisons, the number of nominally significant tests and the comparisons showing the expected direction are in significant excess (permutation p=0.019 and 0.004 respectively). We also find CRP levels highly elevated in SZ, BP and the mothers of BP cases, in agreement with existing literature, but possibly confounded by our inability to correct for smoking or body mass index. In our genome-wide interaction analysis no signal reached genome-wide significance, yet many plausible candidate genes emerged. In a hypothesis driven test, we found multiple interactions among SZ-associated SNPs in the HLA region on chromosome 6 and replicated an interaction between CMV infection and genotypes near the CTNNA3 gene reported by a recent GWAS. Our results support that inflammatory processes and infection may modify the risk for psychosis and suggest that the genotype at SZ-associated HLA loci modifies the effect of these variables on the risk to develop SZ.

Amniotic fluid MMP-9 and neurotrophins in autism spectrum disorders: an exploratory study.

Evidence suggests that some developmental disorders, such as autism spectrum disorders (ASDs), are caused by errors in brain plasticity. Given the important role of matrix metalloproteinases (MMPs) and neurotrophins (NTs) in neuroplasticity, amniotic fluid samples for 331 ASD cases and 698 frequency‐matched controls were analyzed for levels of MMP‐9, brain‐derived neurotrophic factor, NT‐4 and transforming growth factor‐β utilizing a Danish historic birth cohort and Danish nationwide health registers. Laboratory measurements were performed using an in‐house multiplex sandwich immunoassay Luminex xMAP method, and measurements were analyzed using tobit and logistic regression. Results showed elevated levels of MMP‐9 in ASD cases compared with controls (crude and adjusted tobit regression P‐values: 0.01 and 0.06). Our results highlight the importance of exploring the biologic impact of MMP‐9 and potential therapeutic roles of its inhibitors in ASD and may indicate that neuroplastic impairments in ASD may present during pregnancy. Autism Res 2012, 5: 428–433.