Physico-chemical properties of functionally adhesive spider silk nanofibres.

Currently, synthetic fibre production focuses primarily on high performance materials. For high performance fibrous materials, such as silks, this involves interpreting the structure-function relationship and downsizing to a smaller scale to then harness those properties within synthetic products. Spiders create an array of fibres that range in size from the micrometre to nanometre scale. At about 20 nm diameter spider cribellate silk, the smallest of these silks, is too small to contain any of the typical secondary protein structures of other spider silks, let alone a hierarchical skin-core-type structure. Here, we performed a multitude of investigations to elucidate the structure of cribellate spider silk. These confirmed our hypothesis that, unlike all other types of spider silk, it has a disordered molecular structure. Alanine and glycine, the two amino acids predominantly found in other spider silks, were much less abundant and did not form the usual α-helices and ß-sheet secondary structural arrangements. Correspondingly, we characterized the cribellate silk nanofibre to be very compliant. This characterization matches its function as a dry adhesive within the capture threads of cribellate spiders. Our results imply that at extremely small scales there may be a limit reached below which a silk will lose its structural, but not functional, integrity. Nano-sized fibres, such as cribellate silk, thus offer a new opportunity for inspiring the creation of novel scaled-down functional adhesives and nano meta-materials.

Analysis of sex steroids in human tears using LC-MS and GC-MS: Considerations and developments to improve method sensitivity and accuracy.

Sex steroids play a role in regulation of tear film function and may exert their action locally at the ocular surface. However, measurement of sex steroids in tears is difficult due to small-volume tear samples and very low concentrations of the hormones. This short communication highlights what has been achieved to date in the analysis of tear sex steroids using ultra-performance LC-MS (UPLC-MS) as previously published, and reports further and more recent investigations toward optimising mass spectrometry method sensitivity and accuracy. The published UPLC-MS method successfully measured progesterone, androsterone glucuronide and 5α-androstane-3α,17ß-diol in pooled basal tears of postmenopausal women, and fourteen sex steroid standards in methanol. Limitations included sub-optimal limits of detection (LOD) and lower limits of quantification (LLOQ) for some analytes (particularly oestrogens), exclusion of sample matrix effects and no use of internal standards. This update reports on further experiments carried out to improve sensitivity and accuracy. Sample matrix effects, internal standard spiking, and derivatisation with dansyl chloride and oximes were investigated. Dansylation significantly improved the LOD and LLOQ of oestrogens and their metabolites, by a factor of 10 for oestradiol and a factor of 5 for oestrone, but sensitivity of this updated method is not sufficient however for analysis of these oestrogens in human tears. Using gas chromatography-mass spectrometry (GC-MS) as an alternative technique to LC-MS, improved sensitivity for derivatised oestradiol is reported. This work demonstrates the need to develop higher sensitivity methods and points researchers towards specific MS ionisation techniques for future analysis of sex steroids in tears, in order to progress current understanding of the role of sex steroids in tear function and dry eye.

Phospholipid Profiles Are Selectively Altered in the Putamen and White Frontal Cortex of Huntington's Disease.

Huntington's disease (HD) is a genetic, neurodegenerative illness that onsets in late adulthood as a series of progressive and terminal cognitive, motor, and psychiatric deficits. The disease is caused by a polyQ mutation in the Huntingtin gene (HTT), producing a polyglutamine expansion in the Huntingtin protein (HTT). HTT interacts with phospholipids in vitro; however, its interactions are changed when the protein is mutated in HD. Emerging evidence suggests that the susceptibility of brain regions to pathological stimuli is influenced by lipid composition. This study aimed to identify where and how phospholipids are changed in human HD brain tissue. Phospholipids were extracted using a modified MTBE method from the post-mortem brain of 13 advanced-stage HD patients and 13 age- and sex-matched controls. Targeted precursor ion scanning mass spectrometry was used to detect phospholipid species. In the white cortex of HD patients, there was a significantly lower abundance of phosphatidylcholine (PC) and phosphatidylserine (PS), but no difference in phosphatidylethanolamine (PE). In HD putamen, ester-linked 22:6 was lower in all phospholipid classes promoting a decrease in the relative abundance of ester polyunsaturated fatty acids in PE. No differences in phospholipid composition were identified in the caudate, grey cortex or cerebellum. Ether-linked PE fatty acids appear protected in the HD brain, as no changes were identified. The nature of phospholipid alterations in the HD brain is dependent on the lipid (subclass, species, and bond type) and the location.

Quality control concerns in relation to lamotrigine and their impact.

OBJECTIVE: To pursue explanations for compromised efficacy and induction of side-effects in some generic brands of lamotrigine distributed in Australia. METHOD: Bioassays of the non-generic and five generic lamotrigine tablets were undertaken (also after exposure to heat and cold), as well as assays of two generic drugs generating concerning side-effects in two patients, while enquiries were made of manufacturing companies. RESULTS: Mass spectrometry of the six tested products showed comparable properties and no compromising when those tablets were heated and cooled, while analyses of the products taken by the two patients reporting significant side-effects showed an increase in the peak area lamotrigine concentration. CONCLUSIONS: We failed to identify any intrinsically compromised product in our comparison analyses of the six preparations. We consider alternate explanations for an issue leading to widespread international reporting of distinct side-effects and deaths following brand switching, with analyses of the two problematic preparations supporting a 'faulty' batch explanation.

The long and the short of Huntington's disease: how the sphingolipid profile is shifted in the caudate of advanced clinical cases.

Huntington's disease is a devastating neurodegenerative disorder that onsets in late adulthood as progressive and terminal cognitive, psychiatric and motor deficits. The disease is genetic, triggered by a CAG repeat (polyQ) expansion mutation in the Huntingtin gene and resultant huntingtin protein. Although the mutant huntingtin protein is ubiquitously expressed, the striatum degenerates early and consistently in the disease. The polyQ mutation at the N-terminus of the huntingtin protein alters its natural interactions with neural phospholipids in vitro, suggesting that the specific lipid composition of brain regions could influence their vulnerability to interference by mutant huntingtin; however, this has not yet been demonstrated in vivo. Sphingolipids are critical cell signalling molecules, second messengers and membrane components. Despite evidence of sphingolipid disturbance in Huntington's mouse and cell models, there is limited knowledge of how these lipids are affected in human brain tissue. Using post-mortem brain tissue from five brain regions implicated in Huntington's disease (control n = 13, Huntington's n = 13), this study aimed to identify where and how sphingolipid species are affected in the brain of clinically advanced Huntington's cases. Sphingolipids were extracted from the tissue and analysed using targeted mass spectrometry analysis; proteins were analysed by western blot. The caudate, putamen and cerebellum had distinct sphingolipid changes in Huntington's brain whilst the white and grey frontal cortex were spared. The caudate of Huntington's patients had a shifted sphingolipid profile, favouring long (C13-C21) over very-long-chain (C22-C26) ceramides, sphingomyelins and lactosylceramides. Ceramide synthase 1, which synthesizes the long-chain sphingolipids, had a reduced expression in Huntington's caudate, correlating positively with a younger age at death and a longer CAG repeat length of the Huntington's patients. The expression of ceramide synthase 2, which synthesizes very-long-chain sphingolipids, was not different in Huntington's brain. However, there was evidence of possible post-translational modifications in the Huntington's patients only. Post-translational modifications to ceramide synthase 2 may be driving the distinctive sphingolipid profile shifts of the caudate in advanced Huntington's disease. This shift in the sphingolipid profile is also found in the most severely affected brain regions of several other neurodegenerative conditions and may be an important feature of region-specific cell dysfunction in neurodegenerative disease.

Cholesteryl ester levels are elevated in the caudate and putamen of Huntington's disease patients.

Huntington's disease (HD) is an autosomal dominant neurodegenerative illness caused by a mutation in the huntingtin gene (HTT) and subsequent protein (mhtt), to which the brain shows a region-specific vulnerability. Disturbances in neural cholesterol metabolism are established in HD human, murine and cell studies; however, cholesteryl esters (CE), which store and transport cholesterol in the brain, have not been investigated in human studies. This study aimed to identify region-specific alterations in the concentrations of CE in HD. The Victorian Brain Bank provided post-mortem tissue from 13 HD subjects and 13 age and sex-matched controls. Lipids were extracted from the caudate, putamen and cerebellum, and CE were quantified using targeted mass spectrometry. ACAT 1 protein expression was measured by western blot. CE concentrations were elevated in HD caudate and putamen compared to controls, with the elevation more pronounced in the caudate. No differences in the expression of ACAT1 were identified in the striatum. No remarkable differences in CE were detected in HD cerebellum. The striatal region-specific differences in CE profiles indicate functional subareas of lipid disturbance in HD. The increased CE concentration may have been induced as a compensatory mechanism to reduce cholesterol accumulation.

Sterol Analysis by Quantitative Mass Spectrometry.

Analysis of sterols by mass spectrometry is a fundamental technique allowing for both qualitative and quantitative characterization of sterol molecular lipid species. Lipids are isolated from matrix or matrices by homogenization and solvent extraction, and converted into species amenable for ionization either by derivatization or adduct formation. Chromatogaphy (either gas or liquid phase) can assist with the resolution of sterols. Tandem mass spectrometry allows the precise identification of sterol lipid species, while comparison to internal standards added during extraction enables accurate quantification.

Therapeutic Effects of Anthocyanins and Environmental Enrichment in R6/1 Huntington's Disease Mice.

BACKGROUND: Huntington's disease (HD) is a progressive neurodegenerative disease with no effective treatment or cure. Environmental enrichment has been used to slow processes leading to ageing and neurodegenerative diseases including HD. Phenolic phytochemicals including anthocyanins have also been shown to improve brain function in ageing and neurodegenerative diseases. OBJECTIVE: This study examined the effects of anthocyanin dietary supplementation and environmental enrichment on behavioural phenotypes and brain cholesterol metabolic alterations in the R6/1 mouse model of HD. METHODS: R6/1 HD mice and their wild-type littermate controls were randomised into the different experimental conditions, involving either environmentally enriched versus standard housing conditions, or anthocyanin versus control diet. Motor dysfunction was assessed from 6 to 26 weeks using the RotaRod and the hind-paw clasping tests. Gas chromatography - tandem mass spectrometry was used to quantify a broad range of sterols in the striatum and cortex of R6/1 HD mice. RESULTS: Anthocyanin dietary supplementation delayed the onset of motor dysfunction in female HD mice. Environmental enrichment improved motor function and the hind paw clasping phenotype in male HD mice only. These mice also had lower levels of cholesterol oxidation products in the cortex compared to standard-housed mice. CONCLUSION: Both anthocyanin supplementation and environmental enrichment are able to improve the motor dysfunction phenotype of R6/1 mice, however the effectiveness of these interventions was different between the two sexes. The interventions examined did not alter brain cholesterol metabolic deficits that have been reported previously in this mouse model of HD.

Evidence for altered cholesterol metabolism in Huntington's disease post mortem brain tissue.

AIMS: Cholesterol plays an essential role in membrane structure and function, being especially important in the brain. Alteration of brain cholesterol synthesis and metabolism has been demonstrated in several Huntington's disease (HD) mouse and cell models; however, less is known about these alterations in human tissue. This study aimed to identify alterations to cholesterol synthetic and metabolic pathways in human HD brain tissue. METHODS: A broad range of cholesterol synthetic precursors, metabolites and oxidation products were measured by gas chromatography-tandem mass spectrometry in five regions of human post mortem HD brain and compared with age- and sex-matched control tissues. The level of enzymes that regulate cholesterol homeostasis, cholesterol 24-hydroxylase and delta(24)-sterol reductase were investigated by Western blotting and qPCR in putamen. RESULTS: The most significant changes were localized to the putamen, where a 60% decrease in 24(S)-hydroxycholesterol, 30% increase in cholesterol and 100-200% increase in synthetic precursors (lathosterol, zymosterol and desmosterol) was detected. The enzymes cholesterol 24-hydroxylase and delta(24)-sterol reductase were also significantly decreased in HD putamen as compared with control tissues. Free radical-generated cholesterol oxidation products 7-keto cholesterol and 7ß-hydroxycholesterol were also increased by 50-70% in HD putamen. CONCLUSION: Human HD brain has significantly decreased cholesterol metabolism and disrupted cholesterol homeostasis. Our data also indicate that lipid oxidative stress accompanies HD pathology.

Acute reduction in blood pressure following consumption of anthocyanin-rich cherry juice may be dose-interval dependant: a pilot cross-over study.

A pilot cross-over study assessed the acute effects on blood pressure and plasma biomarkers associated with consumption of a 300 ml anthocyanin-rich fruit juice, provided in differing dose-intervals. Young adults (n = 6) and older adults (n = 7) received in random order, either a single 300 ml dose or 3 × 100 ml doses of high-flavonoid cherry juice provided at 0, 1 and 2 h. Blood pressure and plasma levels of phenolic metabolites were measured at 0, 2 and 6 h.The single 300 ml dose of cherry juice resulted in a significant reduction in systolic (p = 0.002), and diastolic blood pressure (p = 0.008) and heart-rate (p = 0.033) 2 h after consumption, before returning to baseline levels at 6 h post-consumption. The 3 × 100 ml dose provided over 2 h did not result in significant blood pressure reductions. Plasma phenolic metabolites increased at 2 and 6 h; however, fluctuations were higher after the single 300 ml dose in older adults. These findings have implications for design of intervention studies that investigate vascular effects associated with flavonoid-rich foods.

Brain Cholesterol Synthesis and Metabolism is Progressively Disturbed in the R6/1 Mouse Model of Huntington's Disease: A Targeted GC-MS/MS Sterol Analysis.

BACKGROUND: Cholesterol has essential functions in neurological processes that require tight regulation of synthesis and metabolism. Perturbed cholesterol homeostasis has been demonstrated in Huntington's disease, however the exact role of these changes in disease pathogenesis is not fully understood. OBJECTIVE: This study aimed to comprehensively examine changes in cholesterol biosynthetic precursors, metabolites and oxidation products in the striatum and cortex of the R6/1 transgenic mouse model of Huntington's disease. We also aimed to characterise the progression of the physical phenotype in these mice. METHODS: GC-MS/MS was used to quantify a broad range of sterols in the striatum and cortex of R6/1 and wild type mice at 6, 12, 20, 24 and 28 weeks of age. Motor dysfunction was assessed over 28 weeks using the RotaRod and the hind-paw clasping tests. RESULTS: 24(S)-Hydroxycholesterol and 27-hydroxycholesterol were the major cholesterol metabolites that significantly changed in R6/1 mice. These changes were specifically localised to the striatum and were detected at the end stages of the disease. Cholesterol synthetic precursors (lathosterol and lanosterol) were significantly reduced in the cortex and striatum by 6 weeks of age, prior to the onset of motor dysfunction, as well as the cognitive and affective abnormalities previously reported. Elevated levels of desmosterol, a substrate of delta(24)-sterol reductase (DHCR24), were also detected in R6/1 mice at the end time-point. Female R6/1 mice exhibited a milder weight loss and hind paw clasping phenotype compared to male R6/1 mice, however, no difference in the brain sterol profile was detected between sexes. CONCLUSION: Several steps in cholesterol biosynthetic and metabolic pathways are differentially altered in the R6/1 mouse brain as the disease progresses and this is most severe in the striatum. This provides further insights into early molecular mediators of HD onset and disease progression and identifies candidate molecular targets for novel therapeutic approaches.

Neuregulin 1 Prevents Phencyclidine-Induced Behavioral Impairments and Disruptions to GABAergic Signaling in Mice.

BACKGROUND: Substantial evidence from human post-mortem and genetic studies has linked the neurotrophic factor neuregulin 1 (NRG1) to the pathophysiology of schizophrenia. Genetic animal models and in vitro experiments have suggested that altered NRG1 signaling, rather than protein changes, contributes to the symptomatology of schizophrenia. However, little is known about the effect of NRG1 on schizophrenia-relevant behavior and neurotransmission (particularly GABAergic and glutamatergic) in adult animals. METHOD: To address this question, we treated adult mice with the extracellular signaling domain of NRG1 and assessed spontaneous locomotor activity and acoustic startle response, as well as extracellular GABA, glutamate, and glycine levels in the prefrontal cortex and hippocampus via microdialysis. Furthermore, we asked whether the effect of NRG1 would differ under schizophrenia-relevant impairments in mice and therefore co-treated mice with NRG1 and phencyclidine (PCP) (3 mg/kg). RESULTS: Acute intraventricularly- or systemically-injected NRG1 did not affect spontaneous behavior, but prevented PCP induced hyperlocomotion and deficits of prepulse inhibition. NRG1 retrodialysis (10 nM) reduced extracellular glutamate and glycine levels in the prefrontal cortex and hippocampus, and prevented PCP-induced increase in extracellular GABA levels in the hippocampus. CONCLUSION: With these results, we provide the first compelling in vivo evidence for the involvement of NRG1 signaling in schizophrenia-relevant behavior and neurotransmission in the adult nervous system, which highlight its treatment potential. Furthermore, the ability of NRG1 treatment to alter GABA, glutamate, and glycine levels in the presence of PCP also suggests that NRG1 signaling has the potential to alter disrupted neurotransmission in patients with schizophrenia.

Apolipoprotein D modulates amyloid pathology in APP/PS1 Alzheimer's disease mice.

Apolipoprotein D (apoD) is expressed in the brain and levels are increased in affected brain regions in Alzheimer's disease (AD). The role that apoD may play in regulating AD pathology has not been addressed. Here, we crossed both apoD-null mice and Thy-1 human apoD transgenic mice with APP-PS1 amyloidogenic AD mice. Loss of apoD resulted in a nearly 2-fold increase in hippocampal amyloid plaque load, as assessed by immunohistochemical staining. Conversely, transgenic expression of neuronal apoD reduced hippocampal plaque load by approximately 35%. This latter finding was associated with a 60% decrease in amyloid ß 1-40 peptide levels, and a 34% decrease in insoluble amyloid ß 1-42 peptide. Assessment of ß-site amyloid precursor protein cleaving enzyme-1 (BACE1) levels and proteolytic products of amyloid precursor protein and neuregulin-1 point toward a possible association of altered BACE1 activity in association with altered apoD levels. In conclusion, the current studies provide clear evidence that apoD regulates amyloid plaque pathology in a mouse model of AD.

Fatty acid composition of the anterior cingulate cortex indicates a high susceptibility to lipid peroxidation in Parkinson's disease.

BACKGROUND: Oxidative stress contributes to Parkinson's disease (PD) etiology. Although previous studies have focused on sources of free radical formation in brain regions affected by PD, less is known regarding changes in lipid composition and the implications for susceptibility to peroxidation. OBJECTIVE: To assess fatty acid profiles from control and PD tissues that are susceptible to PD pathology but devoid of severe destruction. METHODS: We used gas chromatography methods to assess fatty acid profiles from control (n = 10) and PD (n = 9) postmortem tissues. We focused on the anterior cingulate cortex (ACC), a region that accumulates alpha-synuclein, but does not undergo severe destruction, and compared this to the occipital cortex, a region that is pathologically spared. RESULTS: Our data indicate a significant 33% increase in the proportion of polyunsaturated fatty acids (mol%) present in the PD ACC as compared to control ACC. Increases in highly unsaturated 22:5n-6 and 22:6n-3 fatty acids were particularly pronounced (109% and 73%, respectively). Calculation of a peroxidation index (accounting for total fatty acyl double bounds) indicated a 44% increase in susceptibility of the PD ACC to lipid peroxidation compared to control ACC. Such differences were not detected in the occipital cortex from the same donors. Assessment of F2-isprostane levels confirmed that PD tissue lipids were more oxidized than controls. CONCLUSIONS: The global composition of fatty acids in the PD ACC is altered in a way that increases susceptibility to peroxidation in a region-specific manner. This has important implications for PD, supporting the oxidative stress hypothesis of PD pathogenesis.

Long-term cannabidiol treatment prevents the development of social recognition memory deficits in Alzheimer's disease transgenic mice.

Impairments in cognitive ability and widespread pathophysiological changes caused by neurotoxicity, neuroinflammation, oxidative damage, and altered cholesterol homeostasis are associated with Alzheimer's disease (AD). Cannabidiol (CBD) has been shown to reverse cognitive deficits of AD transgenic mice and to exert neuroprotective, anti-oxidative, and anti-inflammatory properties in vitro and in vivo. Here we evaluate the preventative properties of long-term CBD treatment in male AßPPSwe/PS1ΔE9 (AßPP × PS1) mice, a transgenic model of AD. Control and AD transgenic mice were treated orally from 2.5 months of age with CBD (20 mg/kg) daily for 8 months. Mice were then assessed in the social preference test, elevated plus maze, and fear conditioning paradigms, before cortical and hippocampal tissues were analyzed for amyloid load, oxidative damage, cholesterol, phytosterols, and inflammation. We found that AßPP × PS1 mice developed a social recognition deficit, which was prevented by CBD treatment. CBD had no impact on anxiety or associative learning. The prevention of the social recognition deficit was not associated with any changes in amyloid load or oxidative damage. However, the study revealed a subtle impact of CBD on neuroinflammation, cholesterol, and dietary phytosterol retention, which deserves further investigation. This study is the first to demonstrate CBD's ability to prevent the development of a social recognition deficit in AD transgenic mice. Our findings provide the first evidence that CBD may have potential as a preventative treatment for AD with a particular relevance for symptoms of social withdrawal and facial recognition.

Increased apolipoprotein D dimer formation in Alzheimer's disease hippocampus is associated with lipid conjugated diene levels.

Previous studies indicate that apolipoprotein D (apoD) may have a lipid antioxidant function in the brain. We have shown that apoD can reduce free radical-generating lipid hydroperoxides to inert lipid hydroxides in a reaction that involves conversion of surface exposed apoD methione-93 (Met93) residue to Met93-sulfoxide (Met93-SO). One consequence of this reaction is the formation of a stable dimerized form of apoD. As cerebral lipid peroxidation is associated with Alzheimer's disease (AD), in the present study we aimed to assess the possible presence of apoD dimers in postmortem hippocampal and cerebellar tissues derived from a cohort of pathologically defined cases ranging from control to late stage AD. Both soluble and insoluble (requiring guanidine HCl extraction) fractions of tissue homogenates were analyzed for apoD and its dimerized form. We also assessed amyloid-ß levels by ELISA and levels of lipid peroxidation by lipid conjugated diene and F2-isoprostane analysis. Our studies reveal a significant association between soluble apoD levels and AD Braak stage whereas apoD dimer formation appears to increase predominantly in the advanced stages of disease. The formation of apoD dimers is closely correlated to lipid conjugated diene levels and occurs in the hippocampus but not in the cerebellum. These results are consistent with the hypothesis that apoD acts as a lipid antioxidant in the brain.

Lipid anti-lipid antibody responses correlate with disease activity in systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder characterized by broad clinical manifestations including cardiovascular and renal complications with periodic disease flares and significant morbidity and mortality. One of the main contributing factors to the pathology of SLE is the accumulation and impaired clearance of immune complexes of which the principle components are host auto-antigens and antibodies. The contribution of host lipids to the formation of these autoimmune complexes remains poorly defined. The aim of the present study was to identify and analyze candidate lipid autoantigens and their corresponding anti-lipid antibody responses in a well-defined SLE patient cohort using a combination of immunological and biophysical techniques. Disease monitoring in the SLE cohort was undertaken with serial British Isles Lupus Assessment Group (BILAG) scoring. Correlations between specific lipid/anti-lipid responses were investigated as disease activity developed from active flares to quiescent during a follow up period. We report a significant negative correlation between anti-lipid antibodies for 24S-hydroxycholesterol, cardiolipin and phosphatidylserine with SLE disease activity. Taken together, these data suggest that lipid autoantigens represent a new family of biomarkers that can be employed to monitor disease activity plus the efficacy of therapeutic intervention in SLE.

An improved high-throughput lipid extraction method for the analysis of human brain lipids.

We have developed a protocol suitable for high-throughput lipidomic analysis of human brain samples. The traditional Folch extraction (using chloroform and glass-glass homogenization) was compared to a high-throughput method combining methyl-tert-butyl ether (MTBE) extraction with mechanical homogenization utilizing ceramic beads. This high-throughput method significantly reduced sample handling time and increased efficiency compared to glass-glass homogenizing. Furthermore, replacing chloroform with MTBE is safer (less carcinogenic/toxic), with lipids dissolving in the upper phase, allowing for easier pipetting and the potential for automation (i.e., robotics). Both methods were applied to the analysis of human occipital cortex. Lipid species (including ceramides, sphingomyelins, choline glycerophospholipids, ethanolamine glycerophospholipids and phosphatidylserines) were analyzed via electrospray ionization mass spectrometry and sterol species were analyzed using gas chromatography mass spectrometry. No differences in lipid species composition were evident when the lipid extraction protocols were compared, indicating that MTBE extraction with mechanical bead homogenization provides an improved method for the lipidomic profiling of human brain tissue.

Lipid pathway alterations in Parkinson's disease primary visual cortex.

BACKGROUND: We present a lipidomics analysis of human Parkinson's disease tissues. We have focused on the primary visual cortex, a region that is devoid of pathological changes and Lewy bodies; and two additional regions, the amygdala and anterior cingulate cortex which contain Lewy bodies at different disease stages but do not have as severe degeneration as the substantia nigra. METHODOLOGY/PRINCIPAL FINDINGS: Using liquid chromatography mass spectrometry lipidomics techniques for an initial screen of 200 lipid species, significant changes in 79 sphingolipid, glycerophospholipid and cholesterol species were detected in the visual cortex of Parkinson's disease patients (n = 10) compared to controls (n = 10) as assessed by two-sided unpaired t-test (p-value <0.05). False discovery rate analysis confirmed that 73 of these 79 lipid species were significantly changed in the visual cortex (q-value <0.05). By contrast, changes in 17 and 12 lipid species were identified in the Parkinson's disease amygdala and anterior cingulate cortex, respectively, compared to controls; none of which remained significant after false discovery rate analysis. Using gas chromatography mass spectrometry techniques, 6 out of 7 oxysterols analysed from both non-enzymatic and enzymatic pathways were also selectively increased in the Parkinson's disease visual cortex. Many of these changes in visual cortex lipids were correlated with relevant changes in the expression of genes involved in lipid metabolism and an oxidative stress response as determined by quantitative polymerase chain reaction techniques. CONCLUSIONS/SIGNIFICANCE: The data indicate that changes in lipid metabolism occur in the Parkinson's disease visual cortex in the absence of obvious pathology. This suggests that normalization of lipid metabolism and/or oxidative stress status in the visual cortex may represent a novel route for treatment of non-motor symptoms, such as visual hallucinations, that are experienced by a majority of Parkinson's disease patients.