Polycyclic aromatic hydrocarbons (PAHs): Updated aspects of their determination, kinetics in the human body, and toxicity

Polycyclic aromatic hydrocarbons (PAHs) are legacy pollutants of considerable public health concern. Polycyclic aromatic hydrocarbons arise from natural and anthropogenic sources and are ubiquitously present in the environment. Several PAHs are highly toxic to humans with associated carcinogenic and mutagenic properties. Further, more severe harmful effects on human- and environmental health have been attributed to the presence of high molecular weight (HMW) PAHs, that is PAHs with molecular mass greater than 300 Da. However, more research has been conducted using low molecular weight (LMW) PAHs). In addition, no HMW PAHs are on the priority pollutants list of the United States Environmental Protection Agency (US EPA), which is limited to only 16 PAHs. However, limited analytical methodologies for separating and determining HMW PAHs and their potential isomers and lack of readily available commercial standards make research with these compounds challenging. Since most of the PAH kinetic data originate from animal studies, our understanding of the effects of PAHs on humans is still minimal. In addition, current knowledge of toxic effects after exposure to PAHs may be underrepresented since most investigations focused on exposure to a single PAH. Currently, information on PAH mixtures is limited. Thus, this review aims to critically assess the current knowledge of PAH chemical properties, their kinetic disposition, and toxicity to humans. Further, future research needs to improve and provide the missing information and minimize PAH exposure to humans.

Abstract P165: Urinary Amino Acid Profile And Cardiovascular Parameters In Overweight And Obese Brazilian Children

Despite being thoroughly studied, there isn’t complete elucidation of mechanisms underlying obesity, and especially regarding overweight in children. Small molecule metabolites are promising candidates for understanding obesity′s phenotypes. Recent metabolic studies have advanced in discovery of biomarkers for better knowledge of mechanisms related to obesity and its comorbidities. In this cross-sectional study it was evaluated the profile of urinary amino acids of 110 children that were classified in into groups of nutritional status according to their BMI/A (Body Mass Index/age), as normal weight (NW) (n=45), overweight (OW) (n=21) and obese (OB) (n=44). The 24h urine samples were submitted to LC-MS/MS for evaluation of 47 amino acids using Amino Acids Analysis Kit (Zivak®, Turkey), corrected by creatinine concentration. Biochemical profile, cardiovascular parameters and anthropometric measurements were assessed following standard protocols. Girls showed a higher heart rate (G: 82bpm vs B:79bpm, p=0,01 ) than boys. Increased weight presented higher values of systolic blood pressure ( NW: 102.0, OW: 109.0, OB: 110.0; NW vs OW, p = 0.0001; NW vs OB, p = 0.0001 ) and diastolic blood pressure ( NW: 60.0, OW: 67.0, OB: 66.75, NW vs OW, p < 0.0001; NW vs OB, p < 0.0001 ). The following amino acids (expressed in nmol/mg of creatinine) were found in higher concentrations in children’s urine with overweight or obesity, when compared with NW group, glutamine ( NW: 1024.3 vs OW: 1309.2, p=0.05), tryptophan (NW: 85.65, OW:113.55, OB:109.36; NW vs OW p=0.01; OW vs OB p=0.004), phenylalanine (NW: 43.04, OW:49.66, OB:72.08; NW vs OB p=0.01; OW vs OB p=0.04), and Tyrosine (NW: 85.07, OW: 109.74, OB: 140.54; NW vs OB p<0.01; OW vs OB p=0.04). In contrast, sarcosine had reduced concentrations for groups with weight excess (OW: 78.7 vs OB: 62.3, p=0.04). Urine levels of glutamine and aromatic amino acids were higher in OW and OB groups. Tyrosine also showed a positive association with systolic blood pressure values. Thus, there was a positive correlation between levels of glutamine and aromatics amino acids and excess weight, suggesting that they may be candidates to biomarkers for obesity in children. Furthermore, obesity was directly related to increase in blood pressure values.