Nicotinamide riboside kinase-2 regulates metabolic adaptation in the ischemic heart.

Ischemia-induced metabolic remodeling plays a critical role in the pathogenesis of adverse cardiac remodeling and heart failure however, the underlying molecular mechanism is largely unknown. Here, we assess the potential roles of nicotinamide riboside kinase-2 (NRK-2), a muscle-specific protein, in ischemia-induced metabolic switch and heart failure through employing transcriptomic and metabolomic approaches in ischemic NRK-2 knockout mice. The investigations revealed NRK-2 as a novel regulator of several metabolic processes in the ischemic heart. Cardiac metabolism and mitochondrial function and fibrosis were identified as top dysregulated cellular processes in the KO hearts post-MI. Several genes linked to mitochondrial function, metabolism, and cardiomyocyte structural proteins were severely downregulated in the ischemic NRK-2 KO hearts. Analysis revealed significantly upregulated ECM-related pathways which was accompanied by the upregulation of several key cell signaling pathways including SMAD, MAPK, cGMP, integrin, and Akt in the KO heart post-MI. Metabolomic studies identified profound upregulation of metabolites mevalonic acid, 3,4-dihydroxyphenylglycol, 2-penylbutyric acid, and uridine. However, other metabolites stearic acid, 8,11,14-eicosatrienoic acid, and 2-pyrrolidinone were significantly downregulated in the ischemic KO hearts. Taken together, these findings suggest that NRK-2 promotes metabolic adaptation in the ischemic heart. The aberrant metabolism in the ischemic NRK-2 KO heart is largely driven by dysregulated cGMP and Akt and mitochondrial pathways. KEY MESSAGES: Post-myocardial infarction metabolic switch critically regulates the pathogenesis of adverse cardiac remodeling and heart failure. Here, we report NRK-2 as a novel regulator of several cellular processes including metabolism and mitochondrial function post-MI. NRK-2 deficiency leads to downregulation of genes important for mitochondrial pathway, metabolism, and cardiomyocyte structural proteins in the ischemic heart. It was accompanied by upregulation of several key cell signaling pathways including SMAD, MAPK, cGMP, integrin, and Akt and dysregulation of numerous metabolites essential for cardiac bioenergetics. Taken together, these findings suggest that NRK-2 is critical for metabolic adaptation of the ischemic heart.

Nicotinamide riboside kinase-2 inhibits JNK pathway and limits dilated cardiomyopathy in mice with chronic pressure overload.

Nicotinamide riboside kinase-2 (NRK-2) has recently emerged as a critical regulator of cardiac remodeling however, underlying molecular mechanisms is largely unknown. To explore the same, NRK2 knockout (KO) and littermate control mice were subjected to trans-aortic constriction (TAC) or sham surgeries and cardiac function was assessed by serial M-mode echocardiography. A mild cardiac contractile dysfunction was observed in the KOs at the early adaptive phase of remodeling followed by a significant deterioration during the maladaptive cardiac remodeling phase. Consistently, NRK2 KO hearts displayed increased cardiac hypertrophy and heart failure (HF) reflected by morphometric parameters as well as increased fetal genes, atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) expressions. Histological assessment revealed an extensive left ventricular (LV) chamber dilatation accompanied by elevated cardiomyopathy (CM) and fibrosis in the KO hearts post-TAC. In a gain-of-function model, NRK-2 overexpressing in AC16 cardiomyocytes displayed significantly attenuated fetal genes ANP and BNP expression. Consistently, NRK-2 overexpression attenuated angiotensin II (Ang II)-induced cardiomyocyte death. Mechanistically, we identified NRK-2 as a regulator of c-jun N-terminal kinase (JNK) MAP kinase and mitochondrial function where NRK-2 overexpression in human cardiomyocytes markedly suppressed the Ang II-induced JNK activation and mitochondrial depolarization. Thus, our results demonstrate that NRK-2 plays protective roles in pressure overload (PO)-induced dilatative cardiac remodeling and, genetic ablation exacerbates dilated cardiomyopathy (DCM), interstitial collagen deposition, and cardiac dysfunction post-TAC due, in part, to increased JNK activation and mitochondrial dysfunction.

Phthalate metabolites concentrations in amniotic fluid and maternal urine: Cumulative exposure and risk assessment.

Phthalates are used in industry as plasticizers or additives in everyday products and they have been considered as endocrine disrupting chemicals. Maternal exposure during pregnancy has been associated with neonatal exposure, preterm birth and impacts in the reproductive and respiratory systems. The aim of this study is to determine six phthalate metabolites (mono isobutyl phthalate, miBP, mono n-butyl phthalate, mnBP, mono benzyl phthalate, mBzP, mono ethylhexyl phthalate, mEHP, mono 2-ethyl-5-hydroxyhexyl phthalate, mEHHP, mono 2-ethyl-5-oxohexyl-phthalate, mEOHP) in amniotic fluid and urine from 100 pregnant women. Participants answered questionnaires for the use of plastics and cosmetics, dietary habits, health effects, pregnancy problems, health and infant development. Positive amniotic fluid samples ranged from 1% to 21% and urine from 27% to 54%. The median levels for amniotic fluid were 2.3 µg/L - 10.7 µg/L and for urine 4.9 µg/L - 46.7 µg/L. The major results include significant correlations between urinary phthalates indicating their common sources of exposure, the frequent use of deodorant was significantly associated with higher urinary miBP (p = 0.050) and mnBP (p = 0.028) and a weak inverse association was found for the use of make-up products with mBzP (p = 0.053). The frequent use of plastic food containers was significantly associated with urinary mEHP (p = 0.026), and a positive trend was noticed for mEHP in amniotic fluid (p = 0.093). An association although weak was found between urinary mEHP and lower birth length (rs = 0.396, p = 0.062). No other associations were found for infant health problems or development. The daily intake of the total phthalates was calculated 5.4 µg/kg body weight/day which corresponds to hazard index 0.10 and exposure follows the declining trend that has been observed the last decades.

Nicotinamide riboside kinase-2 alleviates ischemia-induced heart failure through P38 signaling.

Nicotinamide riboside kinase-2 (NRK-2), a muscle-specific ß1 integrin binding protein, predominantly expresses in skeletal muscle with a trace amount expressed in healthy cardiac tissue. NRK-2 expression dramatically increases in mouse and human ischemic heart however, the specific role of NRK-2 in the pathophysiology of ischemic cardiac diseases is unknown. We employed NRK2 knockout (KO) mice to identify the role of NRK-2 in ischemia-induced cardiac remodeling and dysfunction. Following myocardial infarction (MI), or sham surgeries, serial echocardiography was performed in the KO and littermate control mice. Cardiac contractile function rapidly declined and left ventricular interior dimension (LVID) was significantly increased in the ischemic KO vs. control mice at 2 weeks post-MI. An increase in mortality was observed in the KO vs. control group. The KO hearts displayed increased cardiac hypertrophy and heart failure reflected by morphometric analysis. Consistently, histological assessment revealed an extensive and thin scar and dilated LV chamber accompanied with elevated fibrosis in the KOs post-MI. Mechanistically, we observed that loss of NRK-2 enhanced p38α activation following ischemic injury. Consistently, ex vivo studies demonstrated that the gain of NRK-2 function suppresses the p38α as well as fibroblast activation (α-SMA expression) upon TGF-ß stimulation, and limits cardiomyocytes death upon hypoxia/re­oxygenation. Collectively our findings show, for the first time, that NRK-2 plays a critical role in heart failure progression following ischemic injury. NRK-2 deficiency promotes post-MI scar expansion, rapid LV chamber dilatation, cardiac dysfunction and fibrosis possibly due to increased p38α activation.

Prehospital Invasive Arterial Pressure: Use of a Minimized Flush System.

IntroductionInvasive blood pressure (IBP) monitoring could be of benefit for certain prehospital patient groups such as trauma and cardiac arrest patients. However, there are disadvantages with using conventional IBP devices. These include time to prepare the transducer kit and flush system as well as the addition of long tubing connected to the patient. It has been suggested to simplify the IBP equipment by replacing the continuous flush system with a syringe and a short stopcock.HypothesisIn this study, blood pressures measured by a standard IBP (sIBP) transducer kit with continuous flush was compared to a transducer kit connected to a simplified and minimized flush system IBP (mIBP) using only a syringe. METHODS: A mechanical, experimental model was used to create arterial pressure pulsations. Measurements were made simultaneously using a sIBP and mIBP device, respectively. This was repeated four times using different mean arterial pressure (MAP): 40, 70, 110, and 140mm Hg. For each series, 16 measurements were taken during 20 minutes. Data were analyzed using Bland-Altman plots. Measurement error greater than five percent was regarded as clinically significant. RESULTS: Mean bias and standard deviation (SD) for systolic blood pressure (SBP), diastolic blood pressure (DBP), and MAP was -3.05 (SD = 2.07), 0.2 (SD = 0.48), and -0.3 (SD = 0.55) mmHg, respectively. Bland-Altman plots revealed that the bias and SD for systolic pressures was mainly due to an increased under-estimation of pressures in lower ranges. All MAP and 98.4% of diastolic pressure measurements had an error of less than five percent. Systolic pressures in the MAP 40 series all had an error of greater than five percent. All other systolic pressures had an error of less than five percent. CONCLUSION: Thus, IBP with the mIBP flush system provides accurate measurement of MAP and DBP in a wide range of physiological pressures. For SBP, there was a tendency to under-estimate pressures, with larger error in lower pressures. Implementation of a simplified flush system could allow further development and potentially simplify the use of IBP for prehospital critical care teams. KarlssonJ, LindeJ, SvensenC, GellerforsM. Prehospital invasive arterial pressure: use of a minimized flush system. Prehosp Disaster Med. 2018;33(5):490-494.

[Moderation-integrated-balance presupposition of Chinese medicine compound and pharmacological problems in traditional Chinese drug research].

The moderation-integrated-balance presupposition (MIBP) of Chinese medicine compound was first proposed in this paper based on the review of function characteristics and action principles of Chinese medicine compound. Furthermore, the pharmacological problems of traditional Chinese drug research were discussed in details. The results were of important value in accelerating the transformation of traditional Chinese medicine compound, and constructing the new drug innovation and review system for traditional Chinese medicine.

Moderation-integrated-balance presupposition of Chinese medicine compound and pharmacological problems in traditional Chinese drug research / 中国中药杂志

The moderation-integrated-balance presupposition (MIBP) of Chinese medicine compound was first proposed in this paper based on the review of function characteristics and action principles of Chinese medicine compound. Furthermore, the pharmacological problems of traditional Chinese drug research were discussed in details. The results were of important value in accelerating the transformation of traditional Chinese medicine compound, and constructing the new drug innovation and review system for traditional Chinese medicine.

Predictors of urinary bisphenol A and phthalate metabolite concentrations in Mexican children.

Exposure to endocrine disrupting chemicals such as bisphenol A (BPA) and phthalates is prevalent among children and adolescents, but little is known regarding important sources of exposure at these sensitive life stages. In this study, we measured urinary concentrations of BPA and nine phthalate metabolites in 108 Mexican children aged 8-13 years. Associations of age, time of day, and questionnaire items on external environment, water use, and food container use with specific gravity-corrected urinary concentrations were assessed, as were questionnaire items concerning the use of 17 personal care products in the past 48-h. As a secondary aim, third trimester urinary concentrations were measured in 99 mothers of these children, and the relationship between specific gravity-corrected urinary concentrations at these two time points was explored. After adjusting for potential confounding by other personal care product use in the past 48-h, there were statistically significant (p<0.05) positive associations in boys for cologne/perfume use and monoethyl phthalate (MEP), mono(3-carboxypropyl) phthalate (MCPP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), and mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), and in girls for colored cosmetics use and mono-n-butyl phthalate (MBP), mono(2-ethylhexyl) phthalate (MEHP), MEHHP, MEOHP, and mono(2-ethyl-5-carboxypentyl) phthalate (MECPP), conditioner use and MEP, deodorant use and MEP, and other hair products use and MBP. There was a statistically significant positive trend for the number of personal care products used in the past 48-h and log-MEP in girls. However, there were no statistically significant associations between the analytes and the other questionnaire items and there were no strong correlations between the analytes measured during the third trimester and at 8-13 years of age. We demonstrated that personal care product use is associated with exposure to multiple phthalates in children. Due to rapid development, children may be susceptible to impacts from exposure to endocrine disrupting chemicals; thus, reduced or delayed use of certain personal care products among children may be warranted.

Phthalates and the diets of U.S. children and adolescents.

BACKGROUND: Di-2-ethylhexylphthalate (DEHP) is an ester of phthalic acid commonly found in processed foods. DEHP may contribute to obesity and insulin resistance in children and adolescents, yet dietary exposures have been not been studied in this vulnerable subpopulation. OBJECTIVE: To assess diet and its relation to urinary phthalates in a nationally representative sample of US children and adolescents. DESIGN: Cross-sectional analysis of 24-h dietary recall and urinary phthalate metabolites from 2743 6-19 year olds participating in the 2003-8 National Health and Nutrition Examination Surveys. Regression analyses examined relationships of food consumption with log-transformed metabolite concentrations, examined as low-molecular weight, high molecular weight and di-2-ethylhexylphthalate categories, controlling for urinary creatinine, age group, body mass index category, race/ethnicity, caloric intake and gender. RESULTS: We identified a -0.04% (95% CI: -0.08, -0.01) increment in di-2-ethylhexylphthalate metabolite concentration/additional gram fruit consumption, a +0.01% increment/additional calorie dietary intake (95% CI: +0.003, +0.02), and a +0.09% (95% CI: +0.02, +0.17) increment/additional gram meat/poultry/fish consumption. Soy consumption (-0.40% increment/additional gram consumed, 95% CI: -0.66, -0.14) was inversely associated with di-2-ethylhexylphthalate, while poultry (+0.23% increment/additional gram consumed, 95% CI: +0.12, +0.35) was positively associated. Findings were robust to examination of metabolite concentrations per unit body mass index and weight, and inclusion of fasting time. CONCLUSIONS: Diet contributes to urinary phthalate concentrations in children and adolescents. Further study is needed to examine the implications of di-2-ethylhexylphthalate exposure, especially earlier in life, when more permanent metabolic changes may occur.

Development and application of simple pharmacokinetic models to study human exposure to di-n-butyl phthalate (DnBP) and diisobutyl phthalate (DiBP).

In a published controlled dosing experiment, a single individual consumed 5mg each of labeled di-n-butyl phthalate (DnBP) and diisobutyl phthalate (DiBP) on separate occasions and tracked metabolites in his blood and urine over 48h. Data from this study were used to structure and calibrate simple pharmacokinetic (PK) models for these two phthalates, which predict urine and blood metabolite concentrations with a given phthalate intake scenario (times and quantities). The calibrated models were applied to a second published experiment in which 5 individuals fasted over the course of a 48-h weekend (bottled water only), and their full urine voids were captured and measured for DnBP and DiBP metabolites. One goal of this model application was to confirm the validity of the calibrated models - their validity would be demonstrated if a profile of intakes could be found which adequately duplicated the metabolite concentrations measured in the urine. A second goal was to study patterns of exposure for this group. It was found that all metabolites could be duplicated very well with individual-specific "best-fit" intake scenarios, with one exception. It appears that the model predicted much lower concentrations of the metabolite, 3carboxy-mono-propylphthalate (MCPP), than were observed in all individuals. Modeled as a metabolite of DnBP, this suggests that DnBP was not the major source of MCPP in the urine. For all 5 individuals, the reconstructed dose profiles of the two phthalates were similar: about 6 small bolus doses per day and an intake of about 0.5µg/kg-day. The intakes did not appear to be associated with diary-reported activities (personal hygiene and medication) of the participants. The modeled frequent intakes suggested one (or both) of two possibilities: ongoing exposures such as an inhalation exposure, or no exposure but rather an ongoing release of body stores of the phthalate metabolites from past exposures.

Phthalates and risk of endometriosis.

BACKGROUND: Phthalates are ubiquitous environmental chemicals with endocrine disruptive properties. The impact of these chemicals on endocrine-related disease in reproductive-age women is not well understood. OBJECTIVE: To investigate the relationship between urinary phthalate metabolite concentrations and the risk of a hormonally-driven disease, endometriosis, in reproductive-age women. METHODS: We used data from a population-based case-control study of endometriosis, conducted among female enrollees of a large healthcare system in the U.S. Pacific Northwest. We measured urinary phthalate metabolite concentrations on incident, surgically-confirmed cases (n=92) diagnosed between 1996 and 2001 and population-based controls (n=195). Odds ratios (OR), and 95% confidence intervals (CI) were estimated using unconditional logistic regression, adjusting for urinary creatinine concentrations, age, and reference year. RESULTS: The majority of women in our study had detectable concentrations of phthalate metabolites. We observed a strong inverse association between urinary mono-(2-ethyl-5-hexyl) phthalate (MEHP) concentration and endometriosis risk, particularly when comparing the fourth and first MEHP quartiles (aOR 0.3, 95% CI: 0.1-0.7). Our data suggested an inverse association between endometriosis and urinary concentrations of other di-2-ethylhexyl phthalate (DEHP) metabolites (mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP)) and ∑DEHP, however, the confidence intervals include the null. Our data also suggested increased endometriosis risk with greater urinary concentrations of mono-benzyl phthalate (MBzP) and mono-ethyl phthalate (MEP), although the associations were not statistically significant. CONCLUSIONS: Exposure to select phthalates is ubiquitous among female enrollees of a large healthcare system in the U.S. Pacific Northwest. The findings from our study suggest that phthalates may alter the risk of a hormonally-mediated disease among reproductive-age women.

Phthalate metabolites in obese individuals undergoing weight loss: Urinary levels and estimation of the phthalates daily intake.

Human exposure to chemicals commonly encountered in our environment, like phthalates, is routinely assessed through urinary measurement of their metabolites. A particular attention is given to the specific population groups, such as obese, for which the dietary intake of environmental chemicals is higher. To evaluate the exposure to phthalates, nine phthalate metabolites (PMs) were analyzed in urine collected from obese individuals and a control population. Obese individuals lost weight through either bariatric surgery or a conservative weight loss program with dietary and lifestyle counseling. Urine samples were also collected from the obese individuals after 3, 6 and 12months of weight loss. Individual daily intakes of the corresponding phthalate diesters were estimated based on the urinary PM concentrations. A high variability was recorded for the levels of each PM in both obese and control urine samples showing the exposure to high levels of PMs in specific subgroups. The most important PM metabolite as percentage contribution to the total PM levels was mono-ethyl phthalate followed by the metabolites of di-butyl phthalate and di 2-ethyl-hexyl phthalate (DEHP). No differences in the PM levels and profiles between obese entering the program and controls were observed. Although paralleled by a significant decrease of their weight, an increase in the urinary PM levels after 3 to 6months loss was seen. Constant figures for the estimated phthalates daily intake were observed over the studied period, suggesting that besides food consumption, other human exposure sources to phthalates (e.g. air, dust) might be also important. The weight loss treatment method followed by obese individuals influenced the correlations between PM levels, suggesting a change of the intake sources with time. Except for few gender differences recorded between the urinary DEHP metabolites correlations, no other differences were observed for the urinary PM levels as a function of age, body mass index or waist circumference. Linear regression analysis showed almost no significance of the relationship between measured urinary PMs and serum free thyroxine, thyroid-stimulating hormone (TSH) for all obese individuals participating to the study, while for the control samples, several PMs were significantly associated with the serum TSH levels.

Prenatal urinary phthalate metabolites levels and neurodevelopment in children at two and three years of age.

BACKGROUND: Previous studies suggest that prenatal phthalate exposure affects neurodevelopment and behavior during the first years of life. OBJECTIVES: To evaluate the effect of maternal urinary concentrations of phthalate metabolites during pregnancy on mental and psychomotor development in children 24-36 months of age. METHODS: This analysis was conducted on the first three years of life among a subsample of 136 mother-child pairs from the ELEMENT cohort studies conducted in Mexico City. Maternal urine samples collected during the third trimester of pregnancy were analyzed for 9 phthalate metabolites: Mono-ethyl phthalate (MEP), Mono-n-butyl phthalate (MnBP), mono-isobutyl phthalate (MiBP), mono-benzyl phthalate (MBzP), Mono-3-carboxypropyl phthalate (MCPP), and four di-2-ethylhexyl phthalate (DEHP) metabolites [mono-2-ethylhexyl-phthalate (MEHP), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), and mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP)]. Among the 136 children, 135 (99.3%) completed the study period. Child neurodevelopment was assessed using mental and psychomotor development indexes (MDI and PDI) from a Bayley (BSID II) test at 24, 30, and 36 months of age. The effect of prenatal phthalate exposure on neurodevelopment was estimated using linear regression models for longitudinal data clustered at the individual level. RESULTS: No significant associations were observed among all children combined, but differential effects by gender were found. Among girls, there was a negative association between MDI and DEHP metabolites MEHP (ß=-2.11 [95% CI: -3.73, -0.49]), MEHHP (ß=-1.89 [95% CI: -3.64, -0.15]), MEOHP (ß=-1.80 [95% CI: -3.58, -0.03]) MECPP (ß=-2.52 [95% CI: -4.44, -0.61]), and ΣDEHP (ß=-3.41 [95% CI: -5.26, -1.55]); there was no significant effect among boys. Male PDI was positively related to MBzP (ß=1.79 [95% CI: 0.14, 3.45]) and MCPP (ß=1.64 [95% CI: 0.15, 3.12]); there was no significant effect on PDI among girls. CONCLUSION: This study demonstrates that sex plays a role of an effect modifier in the association between prenatal phthalate exposure and neurodevelopment.

Urinary excretion of phthalate metabolites, phenols and parabens in rural and urban Danish mother-child pairs.

Some phthalates, parabens and phenols have shown adverse endocrine disrupting effects in animal studies and are also suspected to be involved in human reproductive problems. However, knowledge about exposure sources and biomonitoring data in different subsets of populations are still scarce. Thus, in this study first morning urine samples were collected from 6 to 11 years Danish children and their mothers. The content of seven parabens, nine phenols and metabolites of eight different phthalates were analysed by LC-MS/MS. Two parabens, six phenols and metabolites from six phthalate diesters were measurable in more than 50%, 75% and 90% of the participants, respectively. Thus the children and their mothers were generally exposed simultaneously to a range of phthalates, phenols and parabens. In general, the levels were low but for several of the compounds extreme creatinine adjusted concentrations 100-500-fold higher than the median level were seen in some participants. Children were significantly higher exposed to bisphenol A (BPA) and some of the phthalates (DiBP, DnBP, BBzP, DEHP and DiNP) than their mothers, whereas mothers were higher exposed to compounds related to cosmetics and personal care products such as parabens (MeP, EtP and n-PrP), benzophenone-3, triclosan and diethyl phthalate. However, a very high correlation between mothers and their children was observed for all chemicals. A high individual exposure to one chemical was often associated with a high exposure to other of the chemicals and the possibility of combination effects of multiple simultaneous exposures cannot be excluded.

Biomonitoring of phthalate metabolites in the Canadian population through the Canadian Health Measures Survey (2007-2009).

Human exposure to phthalates occurs through multiple sources and pathways. In the Canadian Health Measures Survey 2007-2009, 11 phthalate metabolites, namely, MMP, MEP, MnBP, MBzP, MCHP, MCPP, MEHP, MEOHP, MEHHP, MnOP, and MiNP were measured in urine samples of 6-49 year old survey respondents (n=3236). The phthalate metabolites biomonitoring data from this nationally-representative Canadian survey are presented here. The metabolites MEP, MnBP, MBzP, MCPP, MEHP, MEOHP and MEHHP were detected in >90% of Canadians while MMP, MCHP, MnOP and MiNP were detected in <20% of the Canadian population. Step-wise regression analyses were carried out to identify important predictors of volumetric concentrations (µg/L) of the metabolites in the general population. Individual multiple regression models with covariates age, sex, creatinine, fasting status, and the interaction terms age×creatinine, age×sex and fasting status×creatinine were constructed for MEP, MnBP, MBzP, MCPP, MEHP, MEOHP and MEHHP. The least square geometric mean (LSGM) estimates for volumetric concentration (µg/L) of the metabolites derived from respective regression models were used to assess the patterns in the metabolite concentrations among population sub-groups. The results indicate that children had significantly higher urinary concentrations of MnBP, MBzP, MEHP, MEHHP, MEOHP and MCPP than adolescents and adults. Moreover, MEP, MBzP, MnBP and MEOHP concentrations in females were significantly higher than in males. We observed that fasting status significantly affects the concentrations of MEHP, MEHHP, MEOHP, and MCPP metabolites analyzed in this study. Moreover, our results indicate that the sampling time could affect the DEHP metabolite concentrations in the general Canadian population.