Effects of sex, age, and fasting conditions on plasma lipidomic profiles of fasted Sprague-Dawley rats.

Circulating lipid molecules reflect biological processes in the body and, thus, are useful tools for preclinical estimation of the efficacy and safety of newly developed drugs. However, background information on profiles of circulating lipid molecules in preclinical animal models is limited. Therefore, we examined the effects of multiple factors such as sex (fasted male vs. female), age (fasted 10 vs. 30 weeks old), and feeding conditions (feeding vs. fasting, 16 vs. 22 hr fasting, 10 AM vs. 4 PM blood collection), on the global profiles of lipid molecules in plasma from Sprague-Dawley rats by using a lipidomic approach. Our assay platform determined 262 lipid molecules (68 phospholipids, 20 sphingolipids, 138 neutral lipids, and 36 polyunsaturated fatty acids and their metabolites) in rat plasma. Multivariate discriminant analysis (orthogonal partial least squares discriminant analysis) and heat maps of statistically significant lipid molecules revealed that the plasma lipid profiles in rats are predominantly influenced by feeding conditions, followed by sex and age. In addition, the fasting duration (16 vs. 22 hr fasting) or the time of blood collection (10 AM vs. 4 PM blood collection) has limited or no contribution on the profiles of lipid molecules in rat plasma. Our results provide useful, fundamental information for exploring and validating biomarkers in future preclinical studies and may help to establish regulatory standards for such studies.

Glucosylceramide and lysophosphatidylcholines as potential blood biomarkers for drug-induced hepatic phospholipidosis.

Drug-induced phospholipidosis is one of the major concerns in drug development and clinical treatment. The present study involved the use of a nontargeting lipidomic analysis with liquid chromatography-mass spectrometry to explore noninvasive blood biomarkers for hepatic phospholipidosis from rat plasma. We used three tricyclic antidepressants (clomipramine [CPM], imipramine [IMI], and amitriptyline [AMT]) for the model of phospholipidosis in hepatocytes and ketoconazole (KC) for the model of phospholipidosis in cholangiocytes and administered treatment for 3 and 28 days each. Total plasma lipids were extracted and measured. Lipid molecules contributing to the separation of control and drug-treated rat plasma in a multivariate orthogonal partial least squares discriminant analysis were identified. Four lysophosphatidylcholines (LPCs) (16:1, 18:1, 18:2, and 20:4) and 42:1 hexosylceramide (HexCer) were identified as molecules separating control and drug-treated rats in all models of phospholipidosis in hepatocytes. In addition, 16:1, 18:2, and 20:4 LPCs and 42:1 HexCer were identified in a model of hepatic phospholipidosis in cholangiocytes, although LPCs were identified only in the case of 3-day treatment with KC. The levels of LPCs were decreased by drug-induced phospholipidosis, whereas those of 42:1 HexCer were increased. The increase in 42:1 HexCer was much higher in the case of IMI and AMT than in the case of CPM; moreover, the increase induced by IMI was dose-dependent. Structural characterization determining long-chain base and hexose delineated that 42:1 HexCer was d18:1/24:0 glucosylceramide (GluCer). In summary, our study demonstrated that d18:1/24:0 GluCer and LPCs are potential novel biomarkers for drug-induced hepatic phospholipidosis.

Plasma and serum lipidomics of healthy white adults shows characteristic profiles by subjects' gender and age.

Blood is a commonly used biofluid for biomarker discovery. Although blood lipid metabolites are considered to be potential biomarker candidates, their fundamental properties are not well characterized. We aimed to (1) investigate the matrix type (serum vs. plasma) that may be preferable for lipid biomarker exploration, (2) elucidate age- and gender-associated differences in lipid metabolite levels, and (3) examine the stability of lipid metabolites in matrix samples subjected to repeated freeze-thaw cycles. Using liquid chromatography-mass spectrometry, we performed lipidomic analyses for fasting plasma and serum samples for four groups (15 subjects/group) of young and elderly (25-34 and 55-64 years old, respectively) males and females and for an additional aliquot of samples from young males, which were subjected to repeated freeze-thaw cycles. Lysophosphatidylcholine and diacylglycerol levels were higher in serum than in plasma samples, suggesting that the clotting process influences serum lipid metabolite levels. Gender-associated differences highlighted that the levels of many sphingomyelin species were significantly higher in females than in males, irrespective of age and matrix (plasma and serum). Age-associated differences were more prominent in females than in males, and in both matrices, levels of many triacylglycerols were significantly higher in elderly females than in young females. Plasma and serum levels of most lipid metabolites were reduced by freeze-thawing. Our results indicate that plasma is an optimal matrix for exploring lipid biomarkers because it represents the original properties of an individual's blood sample. In addition, the levels of some blood lipid species of healthy adults showed gender- and age-associated differences; thus, this should be considered during biomarker exploration and its application in diagnostics. Our fundamental findings on sample selection and handling procedures for measuring blood lipid metabolites is important for ensuring the quality of biomarkers identified and its qualification process.

Lipidomic analysis of brain tissues and plasma in a mouse model expressing mutated human amyloid precursor protein/tau for Alzheimer's disease.

BACKGROUND: Alzheimer's disease (AD), the most common cause of dementia among neurodegenerative diseases, afflicts millions of elderly people worldwide. In addition to amyloid-beta (Aß) peptide and phosphorylated tau, lipid dysregulation is suggested to participate in AD pathogenesis. However, alterations in individual lipid species and their role in AD disease progression remain unclear. METHODS: We performed a lipidomic analysis using brain tissues and plasma obtained from mice expressing mutated human amyloid precursor protein (APP) and tau protein (Tg2576×JNPL3) (APP/tau mice) at 4 (pre-symptomatic phase), 10 (early symptomatic) and 15 months (late symptomatic). RESULTS: Levels of docosahexaenoyl (22:6) cholesterol ester (ChE) were markedly increased in APP/tau mice compared to controls at all stages examined. Several species of ethanolamine plasmalogens (pPEs) and sphingomyelins (SMs) showed different levels between brains from APP/tau and control mice at various stages of AD. Increased levels of 12-hydroxyeicosatetraenoic acid (12-HETE) during the early symptomatic phase were consistent with previous reports using human AD brain tissue. In addition, 19,20-dihydroxy-docosapentaenoic acid (19,20-diHDoPE) and 17,18-dihydroxy-eicosatetraenoic acid (17,18-diHETE), which are produced from docosahexaenoic acid and eicosapentaenoic acid via 19,20-epoxy-docosapentaenoic acid (19,20-EpDPE) and 17,18-epoxy-eicosatetraenoic acid (17,18-EpETE), respectively, were significantly increased in APP/tau brains during the pre-symptomatic phase, and concomitant increases occurred in plasma. Several arachidonic acid metabolites such as prostaglandin D2 (PGD2) and 15-hydroxyeicosatetraenoic acid (15-HETE), which have potential deteriorating and protective actions, respectively, were decreased in the early symptomatic phase of APP/tau mice. Significant decreases in phosphatidylcholines and PEs with polyunsaturated fatty acids were also detected in the late symptomatic phase, indicating a perturbation of membrane properties. CONCLUSION: Our results provide fundamental information on lipid dysregulation during various stages of human AD.

Plasma and serum from nonfasting men and women differ in their lipidomic profiles.

Biomarkers will play important roles in disease diagnosis, drug development, and the proper use of drugs. Blood is considered the best biofluid for biomarker research because it is easy to access and a wealth of data are available. However, previous studies revealed that several ionic metabolites showed different levels (including presence or absence) in plasma and serum. Thus, attention should be paid to selecting the best biofluid for biomarker exploration. Many lipid molecules have biological significance and thus would be candidate biomarkers. However, no comprehensive study revealing differences in lipid metabolite levels between plasma and serum has been undertaken. Furthermore, gender differences have not been reported. To clarify the difference in the levels of lipid metabolites between human plasma and serum from both genders, we performed lipid metabolomic analysis using liquid chromatography-mass spectrometry-based systems for phospholipids (PLs), lysoPLs, sphingomyelins, ceramides and oxidative fatty acids. Our results revealed that most of the lipid metabolites were present at similar levels in plasma and serum and in males and females. However, several oxidative fatty acid metabolites showed differences. Of the metabolites related to clotting processes, three showed higher levels in serum than in plasma, and three were detected only in serum. Furthermore, four metabolites were present at different levels between males and females, and two were detected only in males. Thus, attention should be paid to the selection of plasma or serum when utilizing these lipid metabolites as biomarkers.

Global metabolomic analysis of heart tissue in a hamster model for dilated cardiomyopathy.

Dilated cardiomyopathy (DCM), a common cause of heart failure, is characterized by cardiac dilation and reduced left ventricular ejection fraction, but the underlying mechanisms remain unclear. To investigate the mechanistic basis, we performed global metabolomic analysis of myocardial tissues from the left ventricles of J2N-k cardiomyopathic hamsters. This model exhibits symptoms similar to those of human DCM, owing to the deletion of the δ-sarcoglycan gene. Charged and lipid metabolites were measured by capillary electrophoresis mass spectrometry (MS) and liquid chromatography MS(/MS), respectively, and J2N-k hamsters were compared with J2N-n healthy controls at 4 (presymptomatic phase) and 16weeks (symptomatic) of age. Disturbances in membrane phospholipid homeostasis were initiated during the presymptomatic phase. Significantly different levels of charged metabolites, occurring mainly in the symptomatic phase, were mapped to primary metabolic pathways. Reduced levels of metabolites in glycolysis, the pentose phosphate pathway, and the tricarboxylic acid cycle, together with large decreases in major triacylglycerol levels, suggested that decreased energy production leads to cardiac contractile dysfunction in the symptomatic phase. A mild reduction in glutathione and a compensatory increase in ophthalmate levels suggest increased oxidative stress in diseased tissues, which was confirmed by histochemical staining. Increased levels of 4 eicosanoids, including prostaglandin (PG) E2 and 6-keto-PGF1α, in the symptomatic phase suggested activation of the protective response pathways. These results provide mechanistic insights into DCM pathogenesis and may help identify new targets for therapeutic intervention and diagnosis.

Phylogenetic analysis of urease-positive thermophilic Campylobacter (UPTC) strains based on the molecular characterization of the flaA gene.

Molecular cloning, nucleotide sequencing, and characterization of the flaA gene from additional isolates of urease-positive thermophilic Campylobacter (UPTC) were performed. These isolates were obtained from the natural environment in Northern Ireland (n = 9 from mussels) and in England (n = 1 from sea water). All isolates carried the shorter flaA gene, [open reading frames (ORFs), 1,461 to 1,503 base pairs], without any internal termination codons, and did not carry any flaA pseudogenes. The UPTC isolates were well discriminated by the neighbor joining (NJ) phylogenetic tree constructed based on the putative flaA genes ORFs nucleotide sequence information. In addition, the NJ tree constructed based on the flaA-short variable region sequence information discriminated the Campylobacter lari isolates with a similar degree of discrimination power.

Molecular characterization and phylogenetic analysis of quinolone resistance-determining regions (QRDRs) of gyrA, gyrB, parC and parE gene loci in viridans group streptococci isolated from adult patients with cystic fibrosis.

OBJECTIVES: Ciprofloxacin is the most frequently used member of the fluoroquinolones during initial eradication therapy of Pseudomonas aeruginosa, as well as during acute pulmonary exacerbations. However, its long-term effect on the susceptibility of the commensal flora within the cystic fibrosis (CF) airways has not yet been examined. The aim of this study was therefore to examine the consequence of oral ciprofloxacin usage on the resistance of the commensal viridans group streptococci (VGS), in terms of MICs and mutational analysis of the quinolone resistance-determining regions (QRDRs). METHODS: The MICs of ciprofloxacin, efflux activities and amino acid substitutions in the QRDRs for 190 isolates of VGS, originating from the sputa of adult CF patients who had been exposed constantly to ciprofloxacin, were examined. VGS organisms included Streptococcus salivarius, Streptococcus mitis, Streptococcus sanguinis, Streptococcus oralis, Streptococcus parasanguinis, Streptococcus infantis, Streptococcus gordonii, Streptococcus anginosus, Streptococcus cristatus, Streptococcus australis and Streptococcus mutans. Ciprofloxacin susceptibility was determined by broth microdilution and QRDRs within the gyrA, gyrB, parC and parE gene loci were explored using sequence analysis. RESULTS: Twenty-seven (14.2%) streptococcal isolates were resistant to ciprofloxacin (MICs ≥8 mg/L) and 21 (11.1%) had reduced susceptibility (MICs 4 mg/L). As a comparator, clinically non-significant and non-invasive VGS organisms were examined in 12 consecutive non-CF patients in the community, where no resistance to ciprofloxacin was observed. Five novel QRDR PCR assays were developed to elucidate mutations within the CF VGS population, where there were six positions, which corresponded to previously reported quinolone resistance responsible mutations, and eight novel potential QRDR resistance mutations. Double mutations in gyrA and parC/parE led to MICs of 16 to >64 mg/L, while single mutations in parC or parE resulted in MICs of 8-32 mg/L and 8 mg/L, respectively. The mean homologies of each species to Streptococcus pneumoniae R6 were: gyrA, 70.3%-95%; gyrB, 69.6%-96.2%; parC, 76.1%-94.8%; and parE, 70.7%-94.7%. The close relatives of S. pneumoniae, S. mitis and S. oralis, showed high similarity for all four genes (more than 86%). CONCLUSIONS: Treatment of P. aeruginosa with oral ciprofloxacin in patients with CF may concurrently reduce antibiotic susceptibility in the commensal VGS flora, where these organisms may potentially act as a reservoir of fluoroquinolone resistance gene determinants for newly acquired and antibiotic-susceptible pathogens, particularly the Streptococcus milleri group.

Molecular identification of airborne bacteria associated with aerial spraying of bovine slurry waste employing 16S rRNA gene PCR and gene sequencing techniques.

Polymerase chain reaction amplification of the universal 16S ribosomal RNA (rRNA) gene was performed on a collection of 38 bacterial isolates, originating from air sampled immediately adjacent to the agricultural spreading of bovine slurry. A total of 16 bacterial genera were identified including both Gram-positive and Gram-negative genera. Gram-positive organisms accounted for 34/38 (89.5%) of total bacterial numbers consisting of 12 genera and included Staphylococcus (most common genus isolated), Arthrobacter (2nd most common genus isolated), Brachybacterium, Exiguobacterium, Lactococcus, Microbacterium and Sporosarcina (next most common genera isolated) and finally, Bacillus, Brevibacterium, Frigoribacterium, Mycoplana and Pseudoclavibacter. Gram-negative organisms accounted for only 4/38 (10.5%) bacterial isolates and included the following genera, Brevundimonas, Lysobacter, Psychrobacter and Rhizobium. No gastrointestinal pathogens were detected. Although this study demonstrated a high diversity of the microorganisms present, only a few have been shown to be opportunistically pathogenic to humans and none of these organisms described have been described previously as having an inhalational route of infection and therefore we do not believe that the species of organisms identified pose a significant health and safety threat for immunocompetant individuals.