The inheritance of neuropsychological dysfunction in twins discordant for schizophrenia

While genetic influences in schizophrenia are substantial, the disorder's molecular genetic basis remains elusive. Progress has been hindered by lack of means to detect nonpenetrant carriers of the predisposing genes and by uncertainties concerning the extent of locus heterogeneity. One approach to solving this complexity is to examine the inheritance of pathophysiological processes mediating between genotype and disease phenotype. Here we evaluate whether deficits in neurocognitive functioning covary with degree of genetic relationship with a proband in the unaffected MZ and DZ co-twins of patients with schizophrenia. Twin pairs discordant for schizophrenia were recruited from a total population cohort and were compared with a demographically balanced sample of control twin pairs, on a comprehensive neuropsychological test battery. The following four neuropsychological functions contributed uniquely to the discrimination of degree of genetic loading for schizophrenia and, when combined, were more highly correlated within MZ pairs than within DZ pairs, in both discordant and control twins: spatial working memory (i.e., remembering a sequence of spatial locations over a brief delay), divided attention (i.e., simultaneous performance of a counting and visual-search task), intrusions during recall of a word list (i.e., "remembering" nonlist items), and choice reaction time to visual targets. Together with evidence from human and animal studies of mediation of these functions by partially distinct brain systems, our findings suggest that there are multiple independently inherited dimensions of neural deficit in schizophrenia and encourage a search for genes contributing to quantitative variation in discrete aspects of disease liability. On tests of verbal and visual episodic memory, but not on the liability-related measures, patients were more impaired than their own MZ co-twins, suggesting a preferential impact of nongenetic influences on long-term memory systems.     

The correlation between cellular size and protein expression levels--normalization for global protein profiling

An automated image analysis system was used for protein quantification of 1862 human proteins in 47 cancer cell lines and 12 clinical cell samples using cell microarrays and immunohistochemistry. The analysis suggests that most proteins are expressed in a cell size dependent manner, and that normalization is required for comparative protein quantification in order to correct for the inherent bias of cell size and systematic ambiguities associated with immunohistochemistry. Two reference standards were evaluated, and normalized protein expression values were found to allow for protein profiling across a panel of morphologically diverse cells, revealing putative patterns of over- and underexpression. Using this approach, proteins with stable expression as well as cell-line specific expression were identified. The results demonstrate the value of large-scale, automated proteome analysis using immunohistochemistry, in revealing functional correlations and establishing methods to interpret and mine proteomic data.     

HLA-DR typing in identical twins with insulin-dependent diabetes: difference between concordant and discordant pairs.

A total of 106 pairs of identical twins, of whom 56 were concordant and 50 discordant for insulin-dependent diabetes, were typed for HLA-DR. In both the concordant and discordant groups there was a high prevalence of the antigens DR3 and DR4, a low prevalence of DR5 and DR7, and a virtual absence of DR2. The heterozygous phenotype DR3,DR4 was more prevalent in concordant than discordant pairs. This was therefore the first demonstration of a genetic difference between concordant and discordant identical twin pairs. These findings suggest that possession of both DR3 and DR4 antigens confers a greater genetic predisposition to insulin-dependent diabetes than does the possession of either antigen alone.     

Age-related changes in xanthine oxidase activity and lipid peroxidation,as well as in the correlation between both parameters,in plasma and several organs from female mice

Xanthine oxidase, a purine catabolism enzyme, has been implicated as an important source of oxidant production and plays an essential role in several inflammatory and oxidative stress-related diseases. It is known that the increasing levels of oxidants cause the chronic oxidative stress characteristic of the ageing process. The aim of the present work was to determine the changes in xanthine oxidase activity and oxidative damage to lipids in several organs (liver, kidney, spleen, lung and two different brain areas, namely cerebral cortex and brainstem) and plasma from two different age groups of BALB/c female mice: adult (7-month-old) and old (18-month-old) mice, as well as to analyse the possible correlation between both parameters. Xanthine oxidase activity was significantly increased in liver, cerebral cortex and plasma from old mice in comparison with adults. Similar results were obtained in the lipid peroxidation levels, in which old mice showed a high increment in liver and cerebral cortex. Moreover, the results show a significant and positive correlation between xanthine oxidase activity and lipid peroxidation levels in cerebral cortex. The age-related increase in the xanthine oxidase activity and lipid peroxidation in liver and cerebral cortex of mice seems to suggest that the xanthine oxidase plays a role in the acceleration of the oxidative damage in these organs with age and its possible contribution to the pathophysiological changes associated to the process of ageing.     

Metabolic profiling in validation of plasma biomarkers for green tea polyphenols

Green tea polyphenols (GTP) effectively protect against chronic diseases in various animal models but human studies have been inconclusive. GTP components and metabolites in body fluids have been suggested as potential biomarkers, but validation of these biomarkers has rarely been done in human populations. A randomized, double-blinded, and placebo-controlled phase IIa chemoprevention study with GTP was conducted in 120 human subjects for 3 months. To validate GTP biomarker profiles, plasma samples were collected at baseline, 1-month, and 3-month and were analyzed by HPLC-Coularray electrochemical detection (ECD) for specific GTP components as well as for non-targeted metabolites. The levels of 2 GTP components, epigallocatechin-3-gallate (EGCG) and epicatechin-3-gallate (ECG), were homogenous at baseline (p > 0.45) but were significantly elevated (p < 0.01) by GTP treatment. Metabolic profiling identified 106 metabolites, and 56 of them were chosen to construct discriminant functions (DFs) based on the data at 3 months. The DFs clearly separated the placebo, 500 mg GTP, and 1000 mg GTP groups with an accuracy rate of 97.3%. When the DFs were applied to the combined baseline and 1-month data, the accuracy rate was 62.9% in classifying subjects into the 3 intervention groups. DFs derived from 1-month data showed similar results. Overall, this study validated plasma EGCG and ECG as reliable biomarkers for GTP consumption, and found metabolic profiles effective in discriminating different GTP dosages.     

Methylations in hemoglobin from monozygotic twins discordant for cigarette smoking: hereditary and tobacco-related factors.

Dose monitoring of exogenous methylators by measurement of N-methylvaline in hemoglobin (Hb) is rendered difficult due to a relatively high, variable background in unexposed persons. A kinetic study indicates intracellular S-adenosylmethionine to be a main source of these background methylations. A comparison of twin pairs indicates that the variation in methylvaline levels is partly hereditary (P less than 0.001). Therefore, in a study of monozygotic twin pairs discordant for tobacco smoking the resolving power of the monitoring was increased and in vivo doses of methylators from the smoke could be more easily monitored through their adducts to Hb. Probably, twin studies offer a useful tool for the identification and quantification of electrophiles of endogenous and exogenous origin.     

Metabolomic profiling of regulatory lipid mediators in sputum from adult cystic fibrosis patients

Retained respiratory tract (RT) secretions, infection, and exuberant inflammatory responses are core abnormalities in cystic fibrosis (CF) lung disease. Factors contributing to the destructive CF airway inflammatory processes remain incompletely characterized. The pro-oxidative inflammatory CF RT milieu is known to contain enzymatically and nonenzymatically produced regulatory lipid mediators, a panel of structurally defined oxidized metabolites of polyunsaturated fatty acids known to play a role in pathology related to inflammation. Using an extraction protocol that maximizes recoveries of sputum-spiked deuterated standards, coupled with an LC/MS/MS detection system, this study presents a metabolomic method to assess a broad spectrum of regulatory lipid mediators in freshly obtained sputum from CF patients. A broad range of both proinflammatory and anti-inflammatory lipid mediators was detected, including PGE2, PGD2, TXB2, LTB4, 6-trans-LTB4, 20-OH-LTB4, 20-COOH-LTB4, 20-HETE, 15-HETE, 11-HETE, 12-HETE, 8-HETE, 9-HETE, 5-HETE, EpETrEs, diols, resolvin E1, 15-deoxy-PGJ2, and LXA4. The vast majority of these oxylipins have not been reported previously in CF RT secretions. Whereas direct associations of individual proinflammatory lipid mediators with compromised lung function (FEV-1) were observed, the relationships were not robust. However, multiple statistical analyses revealed that the regulatory lipid mediators profile taken in aggregate proved to have a stronger association with lung function in relatively stable outpatient adult CF patients. Our data reveal a relative paucity of the anti-inflammatory lipid mediator lipoxin A4 in CF sputum. Patients displaying detectable levels of the anti-inflammatory lipid mediator resolvin E1 demonstrated a better lung function compared to those patients with undetectable levels. Our data suggest that comprehensive metabolomic profiling of regulatory lipid mediators in CF sputum should contribute to a better understanding of the molecular mechanisms underlying CF RT inflammatory pathobiology. Further studies are required to determine the extent to which nutritional or pharmacological interventions alter the regulatory lipid mediators profile of the CF RT and the impact of potential modulations of RT regulatory lipid mediators on the clinical progression of CF lung disease.     

Metabolic fingerprinting of blood plasma from patients with prostate cancer

Application of blood plasma metabolites fingerprinting for the diagnostic of the 2nd stage of prostate cancer has been investigated. The diagnostic sensitivity (95%), specificity (96.7%) and accuracy (95.7%) of the metabolic fingerprinting were much higher then those for the ELISA PSA test (35%, 83.3% and 51.7%, respectively) performed for the same patients. Area under the ROC curve (0.994) suggests that the proposed approach based on the metabolic fingerprinting is effective and applicable in clinical practice.     

Influence of personality traits on sexual functioning of patients suffering from schizophrenia or depression

Aim of this research was to establish effects and influence of personality traits on sexual functioning of schizophrenic and depressive patients, compared to healthy individuals. 300 participants were included in this research. For patients suffering from schizophrenia it was established that the more they are open to experience and the less they are neurotic their sexual drive is stronger. For patients suffering from depression it was established that the more they are open to experience and conscientious and the less they are agreeable their sexual drive is stronger. Furthermore, higher openness is a significant predictor for easier sexual arousal and the more those patients are conscientious and the less they are agreeable easier is for them to achieve orgasms. Personality traits proved to be significant predictors of sexual functioning in schizophrenic and depressive patients, but not in healthy individuals.     

Placenta of discordant twins: lack of change in histochemically detectable enzyme activities.

We localised three important enzymes histochemically in placental trophoblasts from women who gave birth to dichorionic discordant twins, in which the co-twin was affected by foetal growth restriction (FGR). The enzymes studied were adenosine diphosphate-degrading enzyme (ADP-degrading enzyme, plasma membrane enzyme), cytochrome c oxidase (mitochondrial enzyme), and glucose-6-phosphatase (endoplasmic reticular enzyme). We compared these enzyme activities and their distribution patterns among placentas of the smaller (FGR) co-twin, larger co-twin, pre-eclamptic singleton with FGR, and normal singletons with birth weight of appropriate for their gestational ages. In FGR co-twin placentas, the intensity and localisation pattern of these three enzymes did not differ from those seen in the larger co-twin and normal singleton placentas. Decreased ADP-degrading activity and cytochrome c oxidase negative mitochondria, which were characteristic features of pre-eclamptic trophoblasts, were not observed in FGR co-twin placentas. These observations indicated that, in the FGR co-twin, enzyme-histochemically detectable trophoblastic cell dysfunction may be absent, or if present, less prominent, compared with pre-eclamptic FGR. We previously reported that placental trophoblasts from singleton idiopathic FGR also showed no reduction in these enzyme activities. In mechanism and pathophysiology, FGR in dichorionic discordant twins may be quite different from pre-eclamptic FGR, but somewhat resembles idiopathic FGR, though all three disorders lead to placental insufficiency, resulting in limited foetal growth.     

Therapeutic modulation of cannabinoid lipid signaling: Metabolic profiling of a novel antinociceptive cannabinoid-2 receptor agonist

AimsAM-1241, a novel, racemic cannabinoid-2 receptor (CB2) ligand, is the primary experimental agonist used to characterize the role of CB2-mediated lipid signaling in health and disease, including substance abuse disorders. In vivo pharmacological effects have been used as indirect proxies for AM-1241 biotransformation processes that could modulate CB2 activity. We report the initial pre-clinical characterization of AM-1241 biotransformation and in vivo distribution.Main methodsAM-1241 metabolism was characterized in a variety of predictive in vitro systems (Caco-2 cells; mouse, rat and human microsomes) and in the mouse in vivo. Liquid chromatography and mass spectrometry techniques were used to quantify AM-1241 tissue distribution and metabolic conversion.Key findingsAM-1241 bound extensively to plasma protein/albumin. A pharmacological AM-1241 dose (25 mg/kg, i.v.) was administered to mice for direct determination of its plasma half-life (37 min), following which AM-1241 was quantified in brain, spleen, liver, and kidney. After p.o. administration, AM-1241 was detected in plasma, spleen, and kidney; its oral bioavailability was ~ 21%. From Caco-2 permeability studies and microsomal-based hepatic clearance estimates, in vivo AM-1241 absorption was moderate. Hepatic microsomal metabolism of AM-1241 in vitro generated hydroxylation and demethylation metabolites. Species-dependent differences were discovered in AM-1241's predicted hepatic clearance. Our data demonstrate that AM-1241 has the following characteristics: a) short plasma half-life; b) limited oral bioavailability; c) extensive plasma/albumin binding; d) metabolic substrate for hepatic hydroxylation and demethylation; e) moderate hepatic clearance.SignificanceThese results should help inform the design, optimization, and pre-clinical profiling of CB2 ligands as pharmacological tools and medicines.