Occurrence and Partitioning of Bisphenol Analogues in Adults’ Blood from China

Widespread human exposure and associated adverse health effects led to regulations on the usage of bisphenol A (BPA). Several bisphenol analogues (BPs) have been introduced as BPA alternatives in various applications. However, these BPs have been shown to exhibit similar or even stronger endocrine-disrupting activities compared with that of BPA. Currently, information on the human exposure to BPA alternatives remains limited. In this study, nine BPs were quantified in 81 pairs of plasma and red blood cell (RBC) samples from Chinese participants. In human plasma, the predominant BPs was BPA, bisphenol S (BPS), and bisphenol AF (BPAF), with the mean concentrations of 0.40, 0.15, and 0.073 ng/mL, respectively. BPA (accounting for 63% of total BPs) and BPS (18%) were the major BPs in the RBC fraction. Mass fractions in plasma (<i>F</i>_p) were found to be highest for BPS (mean, 0.78), followed by BPAF (0.71) and BPA (0.67), indicating strong partitioning to the plasma fraction. However, bisphenol AP was more frequently detected in the RBC fraction. Estimated total daily intake (EDI) of BPA was in the range of 0.0048–0.75 μg/kg bw/day for the participants, and adults aged >50 years had comparatively lower EDI. To our knowledge, this is the first study to assess the occurrence and partitioning of BPA alternatives in paired human plasma and RBCs from the Chinese general population

PLS-DA score plot and validation plot for lysate samples.

<p>(A) PLS-DA score plot of vehicle-treated CHO-wt and CHO-AβPP₆₉₅ lysate samples (R²X = 0.474; R²Y = 0.985; Q² (cum) = 0.808; LV = 2); (B) Validation plot of the PLS-DA model obtained from 100 permutation tests for vehicle-treated lysate samples; (C) PLS-DA score plot of DHA-treated CHO-wt and CHO-AβPP₆₉₅ lysate samples (R²X = 0.645; R²Y = 0.993; Q² (cum) = 0.971; LV = 2); (D) Validation plot of the PLS-DA model obtained from 100 permutation tests for DHA-treated lysate samples.</p

DHA treatment increases pyruvate dehydrogenase enzyme concentration in CHO-wt and CHO-AβPP₆₉₅ cells.

<p>Pyruvate dehydrogenase activity in CHO-wt and CHO-AβPP₆₉₅ cells treated with vehicle or 25 µM DHA. Values are means ± SEM from three independent experiments. **<i>p</i><0.01 and ***<i>p</i><0.001 as compared to CHO-AβPP₆₉₅ vehicle treated. Analysis was done via ANOVA with Bonferroni’s post-hoc analysis.</p

Model validation for CHO-wt and CHO-AβPP₆₉₅ cells and effect of DHA on Aβ₄₀ release.

<p>(A) Conditioned medium was collected from CHO-wt and CHO-AβPP₆₉₅ cells with and without DHA treatment and subjected to ELISA immunoassays for Aβ_40. There was negligible release of Aβ₄₀ from CHO-wt cells as compared to CHO-AβPP₆₉₅ cells at 24 and 48 h. A significant decrease was observed in the release of Aβ₄₀ in CHO-AβPP₆₉₅ cells after treatment with 25 µM DHA for 24 h and 48 h. ^#<i>p</i><0.001 as compared to CHO-wt vehicle treated cells, ^φ<i>p</i><0.05 compared to CHO-AβPP₆₉₅ 24 h vehicle treatment and ^§<i>p</i><0.001 as compared to CHO-AβPP₆₉₅ 48 h vehicle treatment. Analysis was done via ANOVA with Bonferroni’s post-hoc analysis. (B) Western blot analysis of the cell lysates confirm AβPP₆₉₅ plasmid overexpression in CHO-AβPP₆₉₅ cells compared to CHO-wt.</p

Discriminatory marker metabolites identified from medium and lysate samples of DHA-treated and vehicle-treated CHO-wt and CHO-AβPP₆₉₅ cells.

a<p>Metabolite identification using standard compound.</p>b<p>Metabolite identification using NIST library search.</p>c<p>Normalized peak area values expressed as mean ± S.E.M.</p>d<p>Fold change (Δ): CHO-AβPP_{695 (treatment)/}CHO-wt _(treatment).</p><p>*<i>p</i><0.05 and ^ns not significant when calculated using the independent <i>t</i>-test with Welch’s correction for normalized peak area of CHO-AβPP₆₉₅ cells compared to CHO-wt cells for respective treatment groups.</p><p>Abbreviations: DHA – docosahexaenoic acid, TCA – tricarboxylic acid.</p

Metabolites, their associated metabolic pathways and biological relevance in AD.

a<p>Metabolites are grouped together on the basis of their biological relevance. (↑) elevated in AD and (↓) reduced in AD.</p>b<p>Related to metabolites using KEGG database.</p><p>Abbreviations: DHA – docosahexaenoic acid, TCA – tricarboxylic acid.</p

Overlay of GC/TOFMS chromatograms.

<p>(A) Representative GC/TOFMS chromatogram of DHA-treated and vehicle-treated CHO-AβPP₆₉₅ cells – lysate (L) and medium (M) samples (B) Representative chromatogram demonstrating discriminatory metabolites between vehicle-treated and DHA-treated CHO-wt cells and CHO-AβPP₆₉₅ cells.</p

PLS-DA score plot and validation plot for medium samples.

<p>(A) PLS-DA score plot of vehicle-treated CHO-wt and CHO-AβPP₆₉₅ medium samples (R²X = 0.679; R²Y = 0.994; Q² (cum) = 0.929; LV = 3); (B) Validation plot of the PLS-DA model obtained from 100 permutation tests for vehicle-treated medium samples; (C) PLS-DA score plot of DHA-treated CHO-wt and CHO-AβPP₆₉₅ medium samples (R²X = 0.745; R²Y = 0.992; Q² (cum) = 0.885; LV = 3); (D) Validation plot of the PLS-DA model obtained from 100 permutation tests for DHA-treated medium samples.</p

Metabonomic Profiling of Bladder Cancer

Early diagnosis and life-long surveillance are clinically important to improve the long-term survival of bladder cancer patients. Currently, a noninvasive biomarker that is as sensitive and specific as cystoscopy in detecting bladder tumors is lacking. Metabonomics is a complementary approach for identifying perturbed metabolic pathways in bladder cancer. Significant progress has been made using modern metabonomic techniques to characterize and distinguish bladder cancer patients from control subjects, identify marker metabolites, and shed insights on the disease biology and potential therapeutic targets. With its rapid development, metabonomics has the potential to impact the clinical management of bladder cancer patients in the future by revolutionizing the diagnosis and life-long surveillance strategies and stratifying patients for diagnostic, surgical, and therapeutic clinical trials. An introduction to metabonomics, typical metabonomic workflow, and critical evaluation of metabonomic investigations in identifying biomarkers for the diagnosis of bladder cancer are presented

Urinary Metabotyping of Bladder Cancer Using Two-Dimensional Gas Chromatography Time-of-Flight Mass Spectrometry

Cystoscopy is the gold standard clinical diagnosis of human bladder cancer (BC). As cystoscopy is expensive and invasive, it compromises patients’ compliance toward surveillance screening and challenges the detection of recurrent BC. Therefore, the development of a noninvasive method for the diagnosis and surveillance of BC and the elucidation of BC progression become pertinent. In this study, urine samples from 38 BC patients and 61 non-BC controls were subjected to urinary metabotyping using two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC–TOFMS). Subsequent to data preprocessing and chemometric analysis, the orthogonal partial least-squares discriminant analysis (OPLS-DA, R²X = 0.278, R²Y = 0.904 and Q²Y (cumulative) = 0.398) model was validated using permutation tests and receiver operating characteristic (ROC) analysis. Marker metabolites were further screened from the OPLS-DA model using statistical tests. GC×GC–TOFMS urinary metabotyping demonstrated 100% specificity and 71% sensitivity in detecting BC, while 100% specificity and 46% sensitivity were observed via cytology. In addition, the model revealed 46 metabolites that characterize human BC. Among the perturbed metabolic pathways, our clinical finding on the alteration of the tryptophan-quinolinic metabolic axis in BC suggested the potential roles of kynurenine in the malignancy and therapy of BC. In conclusion, global urinary metabotyping holds potential for the noninvasive diagnosis and surveillance of BC in clinics. In addition, perturbed metabolic pathways gleaned from urinary metabotyping shed new and established insights on the biology of human BC