Most studies provide evidence that the skin flush response to nicotinic acid (niacin) stimulation is impaired in schizophrenia. However, only little is known about niacin sensitivity in the ...ultra-high risk (UHR) phase of psychotic disorders.
We compared visual ratings of niacin sensitivity between adolescents at UHR for psychosis according to the one year transition outcome (UHR-T n = 11; UHR-NT n = 55) with healthy controls (HC n = 25) and first episode schizophrenia patients (FEP n = 25) treated with atypical antipsychotics.
Contrary to our hypothesis niacin sensitivity of the entire UHR group was not attenuated, but significantly increased compared to the HC group, whereas no difference could be found between the UHR-T and UHR-NT groups. As expected, niacin sensitivity of FEP was attenuated compared to HC group. In UHR individuals niacin sensitivity was inversely correlated with omega-6 and -9 fatty acids (FA), but positively correlated with phospholipase A2 (inPLA2) activity, a marker of membrane lipid repair/remodelling.
Increased niacin sensitivity in UHR states likely indicates an impaired balance of eicosanoids and omega-6/-9 FA at a membrane level. Our findings suggest that the emergence of psychosis is associated with an increased mobilisation of eicosanoids prior to the transition to psychosis possibly reflecting a "pro-inflammatory state", whereas thereafter eicosanoid mobilisation seems to be attenuated. Potential treatment implications for the UHR state should be further investigated.
Abstract Background Glutamatergic dysfunction and altered membrane lipid and energy metabolism have been repeatedly demonstrated in the frontal/prefrontal and anterior cingulate cortex (ACC) in ...schizophrenia. Though having been already studied in animals, the presumed link between glutamatergic function and structural plasticity has not been investigated directly in the human brain yet. We measured glutamate (Glu), focal energy metabolism, and membrane phospholipid turnover to investigate main pathologies in those key brain regions of schizophrenia. Methods1 H- and31 P-Chemical Shift Imaging (CSI) was combined in a single session to assess Glu and markers of energy (PCr, ATP) and membrane lipid (PME, PDE) metabolism in 31 neuroleptic-naïve first acute onset psychosis patients and 31 matched healthy controls. Multivariate analyses of covariance were used to assess disease effects on Glu and to investigate the impact of Glu alterations on phospholipid and energy metabolites. Results Glu levels of patients were increased in the frontal and prefrontal cortex bilaterally and in the ACC. Higher Glu was associated with increased left frontal/prefrontal PME and right frontal/prefrontal PDE in patients, which was not observed in healthy controls. In contrast, higher Glu levels were associated with lower PCr or ATP values in the frontal/prefrontal cortex bilaterally and in the right ACC of controls. This was not observed in the right ACC and left frontal/prefrontal cortex of patients. Conclusion Frontal glutamatergic hyperactivity is disconnected from physiologically regulated energy metabolism and is associated with increased membrane breakdown in right and increased membrane restoration in left frontal and prefrontal cortical regions. As indicated by previous findings, this pathology is likely dynamic during the course of first acute illness and possibly associated with negative symptoms and cognitive impairment. Our findings underline the importance of further research on neuroprotective treatment options during the early acute or even better for the ultra-high risk state of psychotic illness.
There is considerable evidence for specific pathology of lipid metabolism in schizophrenia, affecting polyunsaturated fatty acids and in particular sphingolipids. These deficits are assumed to ...interfere with neuronal membrane functioning and the development and maintenance of myelin sheaths. Recent studies suggest that some of these lipid pathologies might also be detected in peripheral skin tests. In this study, we examined different skin lipids and their relation to schizophrenia. We assessed epidermal lipid profiles in 22 first-episode antipsychotic-naïve schizophrenia patients and 22 healthy controls matched for age and gender using a hexan/ethanol extraction technique and combined high-performance thin-layer chromatography/gas-chromatography. We found highly significant increase of ceramide AH and NH/AS classes in patients and decrease of EOS and NP ceramide classes. This is the first demonstration of specific peripheral sphingolipid alterations in schizophrenia. The results support recent models of systemic lipid pathology and in particular of specific sphingolipids, which are crucial in neuronal membrane integrity. Given recent findings showing amelioration of psychopathology using fatty acid supplementation, our findings also bear relevance for sphingolipids as potential biomarkers of the disease.
•BDNF heterozygous mice display deficits in the T-maze test.•There is a quadratic association of PLA2 with performance in the open field test.•BDNF deficiency and female sex are associated with ...elevated plasma PLA2 levels.•PLA2 is significantly correlated with adrenal and body weight.
Decreased levels of Brain-Derived Neurotrophic Factor (BDNF) are a common finding in schizophrenia. Another well-documented protein linked to schizophrenia is intracellular Ca2+-independent Phospholipase (PLA2). However, the potential association between PLA2 and BDNF with regard to schizophrenia has yet to be examined.
In the present study, male and female BDNF knockout mice, a possible genetic model of schizophrenia, were exposed to prenatal stress and tested in the nest test, open field test and T-maze. Following behavioral tests, whole brain and plasma samples were harvested to measure the activity of PLA2. BDNF knockout mice showed cognitive deficits in the T-maze. Furthermore, there was a quadratic association of PLA2 with performance in the open field test. Moreover, BDNF deficiency and female sex were associated with elevated plasma PLA2 levels. The cognitive impairment of BDNF heterozygous mice as well as their increased PLA2 activity in plasma is consistent with findings in schizophrenia patients. The particular elevation of PLA2 activity in females may partly explain sex differences of clinical symptoms in schizophrenia (e.g. age of onset, severity of symptoms). Additionally, PLA2 was significantly correlated with body and adrenal weight after weaning, whereby the latter emphasizes the possible connection of PLA2 with steroidogenesis.
Abstract Alterations of immune function have been reported in ultra-high risk (UHR) for psychosis patients causing expectations in terms of predictive meaningfulness and benefits of anti-inflammatory ...agents. According to a RCT in UHR-patients supplementation of omega-3 polyunsaturated fatty acids (PUFA) was effective in reducing transition to psychosis risk and to improve symptomatology. Based on preclinical findings, we now investigated state marker properties of and the influence of PUFA on immune markers in a RCT (clinical trials.gov Identifier: NCT00396643 ). In a longitudinal design we measured plasma levels of the pro-inflammatory interleukin 6 (IL-6), the soluble alpha (Tac) subunit of the interleukin 2 receptor (sIL-2r), and the circulating soluble form of the intercellular adhesion molecule one (sICAM-1), in 79 help-seeking UHR individuals (13–25 years of age). Using linear mixed model (LMM) analysis, we investigated the effects of 12 weeks supplementation of either 1.2 g/d PUFA (n = 38) or Placebo (n = 41). At baseline, inflammatory markers were not altered in patients who later suffered transition to psychosis within one year (n = 12; 11 PUFA-group, 1 PL-group). IL-6 was weakly inverse associated with omega-6 PUFA, and highly increased in nicotine users. In univariate tests of the LMM omega-3 PUFA caused a significant increase of sICAM-1 (p = 0.022). PUFA did not significantly influence IL-6 or sIL-2r. The enhancement of sICAM-1 in the PUFA condition is suggestive for supportive effects on vascular immune response and immediate Th1 helper cell mediated immune answer, which was found disturbed in manifest schizophrenia, e.g. by facilitating the leukocyte adhesion and migration across the endothelium.
Abstract Background Oxidative stress and impaired antioxidant defenses are reported in schizophrenia and are associated with disturbed neurodevelopment, brain structural alterations, glutamatergic ...imbalance, increased negative symptoms, and cognitive impairment. There is evidence that oxidative stress predates the onset of acute psychotic illness. Here, we investigate the effects of omega-3 PUFA on the vitamin E and glutathione antioxidant defense system (AODS). Method In 64 help-seeking UHR-individuals (13–25 years of age), vitamin E levels and glutathione were investigated before and after 12 weeks of treatment with either 1.2 g/d omega-3 (PUFA-E) or saturated fatty acids (SFA-E), with each condition also containing 30.4 mg/d alpha-tocopherol to ensure absorption without additional oxidative risk. Results In multivariate tests, the effects on the AODS (alpha-tocopherol, total glutathione) were not significantly different ( p =0.13, p =0.11, respectively) between treatment conditions. According to univariate findings, only PUFA-E caused a significant alpha-tocopherol increase, while PUFA-E and SFA-E caused a significant gamma- and delta-tocopherol decrease. Total glutathione (GSHt) was decreased by PUFA-E supplementation. Conclusion Effects of the PUFA-E condition on the vitamin E and glutathione AODS could be mechanisms underlying its clinical effectiveness. In terms of the vitamin E protection system, PUFA-E seems to directly support the antioxidative defense at membrane level. The effect of PUFA-E on GSHt is not yet fully understood, but could reflect antioxidative effects, resulting in decreased demand for glutathione. It is still necessary to further clarify which type of PUFA/antioxidant combination, and in which dose, is effective at each stage of psychotic illness.
•Physiological phospholipase A2 activity levels are associated with brain white matter microstructure across adolescence.•Membrane docosahexaenoic acid concentration is associated with white matter ...microstructure across adolescence.•White matter development may involve cleavage of docosahexaenoic acid from membrane phospholipids by phospholipase A2.•Docosahexaenoic acid and phospholipase A2 may be implicated in myelin-related neurodevelopmental disorders.
Adolescence is a period of major brain white matter (WM) changes, and membrane lipid metabolism likely plays a critical role in brain WM myelination. Long-chain polyunsaturated fatty acids (LC-PUFAs) are essential components of cell membranes including oligodendrocytes, and LC-PUFA release and turnover in membranes is regulated by phospholipase A2 enzymes. To investigate the role of membrane lipid metabolism in healthy WM myelination across adolescence, the present study examined the relationship between membrane LC-PUFA biostatus, phospholipase A2 activity, and brain WM microstructure in healthy subjects aged 9–20years (n=30). Diffusion tensor imaging (DTI) was performed to measure average fractional anisotropy (FA) and diffusivity (indices sensitive to WM myelination) of nine major cerebral WM tracts. Blood samples were collected to measure erythrocyte membrane fatty acid concentrations and plasma intracellular phospholipase A2 activity (inPLA2). Plasma inPLA2 activity showed a significant U-curved association with WM radial diffusivity, and an inverted U-curved association with WM FA, independent of age. A significant positive linear correlation was observed between docosahexaenoic acid concentration and axial diffusivity in the corpus callosum. These findings suggest that there may be optimal physiological inPLA2 activity levels associated with healthy WM myelination in late childhood and adolescence. Myelination may be mediated by cleavage of docosahexaenoic acid from membrane phospholipids by inPLA2. These findings have implications for our understanding of the role of LC-PUFA homeostasis in myelin-related neurodevelopmental disorders.
Schizophrenia can be conceptualized as a form of dysconnectivity between brain regions.To investigate the neurobiological foundation of dysconnectivity, one approach is to analyze white matter ...structures, such as the pathology of fiber tracks. S100B is considered a marker protein for glial cells, in particular oligodendrocytes and astroglia, that passes the blood brain barrier and is detectable in peripheral blood. Earlier Studies have consistently reported increased S100B levels in schizophrenia. In this study, we aim to investigate associations between S100B and structural white matter abnormalities.
We analyzed data of 17 unmedicated schizophrenic patients (first and recurrent episode) and 22 controls. We used voxel based morphometry (VBM) to detect group differences of white matter structures as obtained from T1-weighted MR-images and considered S100B serum levels as a regressor in an age-corrected interaction analysis.
S100B was increased in both patient subgroups. Using VBM, we found clusters indicating significant differences of the association between S100B concentration and white matter. Involved anatomical structures are the posterior cingulate bundle and temporal white matter structures assigned to the superior longitudinal fasciculus.
S100B-associated alterations of white matter are shown to be existent already at time of first manifestation of psychosis and are distinct from findings in recurrent episode patients. This suggests involvement of S100B in an ongoing and dynamic process associated with structural brain changes in schizophrenia. However, it remains elusive whether increased S100B serum concentrations in psychotic patients represent a protective response to a continuous pathogenic process or if elevated S100B levels are actively involved in promoting structural brain damage.
Regional structural brain changes are among the most robust biological findings in schizophrenia, yet the underlying pathophysiological changes remain poorly understood. Recent evidence suggests that ...abnormal neuronal/dendritic plasticity is related to alterations in membrane lipids. We examined whether serum activity of membrane lipid remodelling/repairing cytosolic phospholipase A2 (PLA2) were related to regional brain structure in magnetic resonance images (MRI). The study involved 24 schizophrenia patients, who were either drug-naïve or off antipsychotic medication, and 25 healthy controls. Using voxel-based morphometry (VBM) analysis of T1-high-resolution MRI-images, we correlated both gray matter and white matter changes with serum PLA2-activity. PLA2 activity was increased in patients, consistent with previous findings. VBM group comparison of patients vs. controls showed abnormalities of frontal and medial temporal cortices/hippocampus, and left middle/superior temporal gyrus in first-episode patients. Group comparison of VBM/PLA2-correlations revealed a distinct pattern of disease-related interactions between gray/white matter changes in patients and PLA2-activity: in first-episode patients (n=13), PLA2-activity was associated with structural alterations in the left prefrontal cortex and the bilateral thalamus. Recurrent-episode patients (n=11) showed a wide-spread pattern of associations between PLA2-activity and structural changes in the left (less right) prefrontal and inferior parietal cortex, the left (less right) thalamus and caudate nucleus, the left medial temporal and orbitofrontal cortex and anterior cingulum, and the cerebellum. Our findings demonstrate a potential association between membrane lipid biochemistry and focal brain structural abnormalities in schizophrenia. Differential patterns in first-episode vs. chronic patients might be related to PLA2-increase at disease-onset reflecting localized regenerative activity, whereas correlations in recurrent-episode patients might point to less specific neurodegenerative aspects of disease progression.
•In acutely ill antipsychotic-free schizophrenia patients: increase of TH2 system cytokine IL-13 (p = 0.039).•Decrease of TH1 system markers sICAM-1 (p = 0.011) and sIL-2R (p = 0.063).•Effect of ...sIL-2R decrease greater in the FEP subgroup (p = 0.01).•Increase of pro-inflammatory IL-6 not significant (p = 0.052). No group differences in: IL-4, IL-8, TNF-alpha, and IFN-gamma.•Findings support the notion of a TH1/TH2 imbalance particularly in the acute manifestation phase of schizophrenia.
There is major evidence for the involvement of immunological processes in the pathophysiology of schizophrenia. Especially alterations of T-cell function and activation of the inflammatory response system appear to be linked to schizophrenia. A mild chronic inflammation process has been proposed and repeated findings of altered serum cytokine levels led to the hypothesis of a TH2 shift or cytokine imbalance in schizophrenia. We investigated serum levels of TH1 and TH2 related cytokines and immune markers in 25 patients suffering an acute schizophrenic episode (all unmedicated, 22 neuroleptica-naïve) at different stages of disorder (18 first episode, FEP; 7 recurrent episode, REP) compared to 25 age and sex matched healthy controls.
In patients, we found an increase of the TH2 system cytokine IL-13 (p = 0.039) and a decrease of the TH1 system markers sICAM-1 (p = 0.011) and sIL-2R (p = 0.063, n. s.). Elevation of the pro-inflammatory cytokine IL-6 was not significant (p = 0.052). The effect of sIL-2R decrease was greater in the FEP subgroup (p = 0.01) of patients. We found no group differences in the other investigated immune markers: IL-4, IL-8, TNF-alpha, and Interferon-gamma, in which most readings were below the lower detection limit of the respective assay.
Our findings support the notion of a TH1/TH2 imbalance particularly in the acute manifestation phase of schizophrenia. In the long run, this may lead to the identification of cytokine patterns that are applicable as trait or state markers, may be helpful in making or ensuring diagnosis or in monitoring therapy.
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