1
|
Marchand A, Ménard J, Brochu P, Haddad S. Modeling the impact of heat stress on the toxicokinetics of toluene and acetone. Arch Toxicol 2024; 98:471-479. [PMID: 38127129 DOI: 10.1007/s00204-023-03646-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 11/16/2023] [Indexed: 12/23/2023]
Abstract
Many workers can be exposed simultaneously to heat and volatile chemicals. In a controlled human exposure study, it was observed that an increase in ambient temperature was associated with increased blood concentrations for acetone and toluene. Based on the expected changes in physiological parameters that occur with an increase in ambient temperature, we aimed to develop a PBPK model for acetone and toluene that could account for the impact of temperature on the kinetics of these solvents. Changes in temperature-dependent physiological parameters (i.e. blood flows, cardiac output, alveolar ventilation) based on recent measurements in volunteers were introduced in the PBPK models to simulate observed blood concentrations for different temperature exposure conditions. Because initial simulations did not adequately predict solvent kinetics at any temperature, the most sensitive parameter (alveolar ventilation; Qp) was, therefore, optimized on experimental acetone blood concentrations to obtain a relationship with temperature. The new temperature-dependent Qp relationship gave Qp values consistent with the literature and estimated a mean increase of 19% at 30 °C (wet bulb globe temperature) compared to 21 °C. The integration of a new temperature-dependent Qp relationship in the PBPK toluene model yielded adequate simulations of the experimental data for toluene in blood, exhaled air and urine. With further validation with other solvents, the temperature-dependant PBPK model could be a useful tool to better assess the risks of simultaneous exposure to volatile chemicals and heat stress and interpret biomonitoring data in workers as well as in the general population. TRN: NCT02659410, Registration date: January 15, 2016.
Collapse
Affiliation(s)
- Axelle Marchand
- Centre de recherche en santé publique, Université de Montréal, C.P. 6128 Succ. Centre-ville, Montreal, (Qc.), H3C 3J7, Canada
- Department of Environmental and Occupational Health, ESPUM, Université de Montréal, C.P. 6128 Succ. Centre-ville, Montreal, (Qc.), H3C 3J7, Canada
- Chair in Toxicological Risk Assessment and Management, Université de Montréal, Montreal, (Qc.), Canada
| | - Jessie Ménard
- Centre de recherche en santé publique, Université de Montréal, C.P. 6128 Succ. Centre-ville, Montreal, (Qc.), H3C 3J7, Canada
- Chair in Toxicological Risk Assessment and Management, Université de Montréal, Montreal, (Qc.), Canada
| | | | - Sami Haddad
- Centre de recherche en santé publique, Université de Montréal, C.P. 6128 Succ. Centre-ville, Montreal, (Qc.), H3C 3J7, Canada.
- Chair in Toxicological Risk Assessment and Management, Université de Montréal, Montreal, (Qc.), Canada.
| |
Collapse
|
2
|
Brochu P, Ménard J, Haddad S. Cardiopulmonary parameters and organ blood flows for workers expressed in terms of VO2 for use in physiologically based toxicokinetic modeling. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2022; 85:307-335. [PMID: 34991435 DOI: 10.1080/15287394.2021.2006845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Minute ventilation rates (VE), alveolar ventilation rates (VA), cardiac outputs (Q), liver blood flow (LBF) and kidneys blood flows (KBF) for physiologically based toxicokinetic modeling and occupational health risk assessment in active workers have apparently not been determined. Minute energy expenditure rates (E) and oxygen consumption rates (VO2) in workers during exertions and their aggregate daytime activities are obtained by using open-circuit wearable devices for indirect calorimetry measurements and the doubly labeled water method respectively. Hundreds of E (in kcal/min) and VO2 (in L of O2/min) were previously reported for workers. The oxygen uptake factors of 0.2059 ± 0.0019 and 0.2057 ± 0.0018 L of O2/kcal during postprandial and fasting phases respectively enabled conversion of E into VO2. Equations determined in this study based upon more than 25 000 published measurements enable the calculation of 15 parameters in the same worker only by using the VO2 reflecting workload. These parameters, notably VE, VA, VE/VO2 VA/Q, Q, LBF and KBF were found to be interrelated. Altering one of these changes the order of magnitude of the others. Q, LBF and KBF decrease when supine adults at rest switch to an upright position. This effect of gravity diminished when VO2 increased. The fall in LBF and KBF during exertion might enhance muscle blood flow as reported previously. Taken together these equations and data may improve the accuracy of physiologically based toxicokinetic modeling as well as occupational health assessment studies in active workers exposed to xenobiotics.List of main abbreviations: AVOD: arterioveinous oxygen content difference.BMI: body mass index (in kg/m2).BSA: body surface area (in m2).BTPS: body temperature and saturated with water vapor.Bw: body weight (in kg).E: minute energy expenditure rate (in kcal/min).FGE: organ blood flow factor for the gravitational effect on blood circulation.H: oxygen uptake factor, volume of oxygen (at STPD) consumed to produce 1 kcal of energy expended.KBF: kidneys blood flow (in ml/min).LBF: liver blood flow (in ml/min).PBF: liver or kidneys blood flows expressed in terms of percentages (in %) of Qsup C values: namely PBF = (LBF or KBF/Qsup C) x 100.Q: cardiac output (in L/min or ml/min).Qsup C: cardiac output for the cohort of males or females in supination (in ml/min).STPD: standard temperature and pressure, dry air.sup: values measured when adults are in the supine position.up: values measured when adults are in the upright position.VDphys: physiological dead space at BTPS (in L).VT: tidal volume at BTPS (in L).VA: alveolar ventilation rate at BTPS (in L/min).VA/Q: ventilation-perfusion ratio (unitless).VE: minute ventilation rate at BTPS (in L/min).VO2: oxygen consumption rate (i.e. the oxygen uptake) at STPD (in L/min).VQ: ventilatory equivalent for VO2 (VE at BTPS /VO2 at STPD).
Collapse
Affiliation(s)
- Pierre Brochu
- Department of Environmental and Occupational Health, ESPUM, Université de Montréal, Montreal, QC, Canada
| | - Jessie Ménard
- Department of Environmental and Occupational Health, ESPUM, Université de Montréal, Montreal, QC, Canada
- Centre for Public Health Research (CReSP), Université de Montréal, Montréal, QC, Canada
| | - Sami Haddad
- Department of Environmental and Occupational Health, ESPUM, Université de Montréal, Montreal, QC, Canada
- Centre for Public Health Research (CReSP), Université de Montréal, Montréal, QC, Canada
| |
Collapse
|
3
|
Marchand A, Ménard J, Brochu P, Haddad S. Impact of heat on biological concentrations of toluene and acetone resulting from exposure by inhalation: A pilot study. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2021; 88:103737. [PMID: 34481063 DOI: 10.1016/j.etap.2021.103737] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 08/27/2021] [Accepted: 08/30/2021] [Indexed: 06/13/2023]
Abstract
Climatic conditions raise new concerns about the potential impact of heat on the absorption and kinetics of certain chemicals. The impact of 3 temperatures (21, 25 and 30 °C WBGT) on the toxicokinetics of toluene and acetone was therefore evaluated in five human subjects during controlled exposures in an inhalation chamber. Biological samples were collected and analyzed by GC-MS/MS. Increases between 4 and 85 % were observed for solvents concentrations in blood (30 vs 21 °C) while decreases in urine samples for acetone and o-cresol were measured at the end of the exposure period (4 h). Mean blood concentrations at 4 h are well correlated with temperature. Results suggest an increased absorption and/or a decreased elimination of volatile chemicals in the presence of heat. Higher increases of blood chemical concentrations were observed in heavier individuals. Further studies should include physiologically based toxicokinetic models to help in better understanding the mechanisms involved and their respective contribution.
Collapse
Affiliation(s)
- Axelle Marchand
- Centre for Public Health Research (CReSP), 7101 Parc Avenue, Montreal, Quebec, H3N 1X9, Canada; Department of Environmental and Occupational Health, ESPUM, Université de Montréal, P.O. Box 6128, Downtown Branch, Montreal, Quebec, H3C 3J7, Canada
| | - Jessie Ménard
- Centre for Public Health Research (CReSP), 7101 Parc Avenue, Montreal, Quebec, H3N 1X9, Canada; Department of Environmental and Occupational Health, ESPUM, Université de Montréal, P.O. Box 6128, Downtown Branch, Montreal, Quebec, H3C 3J7, Canada
| | - Pierre Brochu
- Department of Environmental and Occupational Health, ESPUM, Université de Montréal, P.O. Box 6128, Downtown Branch, Montreal, Quebec, H3C 3J7, Canada
| | - Sami Haddad
- Centre for Public Health Research (CReSP), 7101 Parc Avenue, Montreal, Quebec, H3N 1X9, Canada; Department of Environmental and Occupational Health, ESPUM, Université de Montréal, P.O. Box 6128, Downtown Branch, Montreal, Quebec, H3C 3J7, Canada.
| |
Collapse
|