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Is exogenous hydrogen sulfide a relevant tool to address physiological questions on hydrogen sulfide?
Respir Physiol Neurobiol 2016; 229:5-10RP

Abstract

This review challenges the use of solutions of dissolved exogenous H2S in the literature as a tool to determine the potential physiological functions of endogenous H2S as well as its putative therapeutic applications. Our major point of contention is that solutions of dissolved H2S are used in vitro at concentrations, within the high microM range, which are above the concentrations of dissolved H2S found in blood and tissues during lethal H2S exposure in vivo. In addition, since the levels of toxicity are extremely variable among cell types, a property that is seldom acknowledged, the physiological relevance of data obtained after local or in-vitro administrations of H2S at concentrations of few microM is far from certain. Conversely, the rate of disappearance of the dissolved pool of H2S in the body (being trapped or oxidized), which we found to be at least of several micromoles/kg/min, is so rapid in vivo that if relatively low quantities of H2S, i.e. few micromoles for instance, are administered, no change in H2S concentrations in the body is to be expected, unless toxic levels are used. Protocols looking at the effects of compounds slowly releasing H2S must also resolve a similar conundrum, as their effects must be reconciled with the unique ability of the blood and tissues to get rid of H2S and the steepness of the dose-toxic effects relationship. Only by developing a comprehensive framework in which H2S metabolism and toxicity will be used as a rationale to justify any experimental approach will we be able to bring definitive evidence supporting a protective role for exogenous H2S, if any, and its putative function as an endogenous mediator.

Authors+Show Affiliations

Pennsylvania State University, College of Medicine, Division of Pulmonary and Critical Care Medicine, Department of Medicine, 500 University Drive, H041, Hershey, PA 17033 USA. Electronic address: phaouzi@hmc.psu.edu.

Pub Type(s)

Journal Article
Review
Research Support, N.I.H., Extramural

Language

eng

PubMed ID

27045466

Citation

Haouzi, Philippe. "Is Exogenous Hydrogen Sulfide a Relevant Tool to Address Physiological Questions On Hydrogen Sulfide?" Respiratory Physiology & Neurobiology, vol. 229, 2016, pp. 5-10.
Haouzi P. Is exogenous hydrogen sulfide a relevant tool to address physiological questions on hydrogen sulfide? Respir Physiol Neurobiol. 2016;229:5-10.
Haouzi, P. (2016). Is exogenous hydrogen sulfide a relevant tool to address physiological questions on hydrogen sulfide? Respiratory Physiology & Neurobiology, 229, pp. 5-10. doi:10.1016/j.resp.2016.03.015.
Haouzi P. Is Exogenous Hydrogen Sulfide a Relevant Tool to Address Physiological Questions On Hydrogen Sulfide. Respir Physiol Neurobiol. 2016 07 15;229:5-10. PubMed PMID: 27045466.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Is exogenous hydrogen sulfide a relevant tool to address physiological questions on hydrogen sulfide? A1 - Haouzi,Philippe, Y1 - 2016/03/30/ PY - 2016/02/16/received PY - 2016/03/25/revised PY - 2016/03/27/accepted PY - 2016/4/6/entrez PY - 2016/4/6/pubmed PY - 2017/8/2/medline KW - Gaseous transmitter KW - Hydrogen sulfide KW - Toxicology SP - 5 EP - 10 JF - Respiratory physiology & neurobiology JO - Respir Physiol Neurobiol VL - 229 N2 - This review challenges the use of solutions of dissolved exogenous H2S in the literature as a tool to determine the potential physiological functions of endogenous H2S as well as its putative therapeutic applications. Our major point of contention is that solutions of dissolved H2S are used in vitro at concentrations, within the high microM range, which are above the concentrations of dissolved H2S found in blood and tissues during lethal H2S exposure in vivo. In addition, since the levels of toxicity are extremely variable among cell types, a property that is seldom acknowledged, the physiological relevance of data obtained after local or in-vitro administrations of H2S at concentrations of few microM is far from certain. Conversely, the rate of disappearance of the dissolved pool of H2S in the body (being trapped or oxidized), which we found to be at least of several micromoles/kg/min, is so rapid in vivo that if relatively low quantities of H2S, i.e. few micromoles for instance, are administered, no change in H2S concentrations in the body is to be expected, unless toxic levels are used. Protocols looking at the effects of compounds slowly releasing H2S must also resolve a similar conundrum, as their effects must be reconciled with the unique ability of the blood and tissues to get rid of H2S and the steepness of the dose-toxic effects relationship. Only by developing a comprehensive framework in which H2S metabolism and toxicity will be used as a rationale to justify any experimental approach will we be able to bring definitive evidence supporting a protective role for exogenous H2S, if any, and its putative function as an endogenous mediator. SN - 1878-1519 UR - https://www.unboundmedicine.com/medline/citation/27045466/Is_exogenous_hydrogen_sulfide_a_relevant_tool_to_address_physiological_questions_on_hydrogen_sulfide L2 - https://linkinghub.elsevier.com/retrieve/pii/S1569-9048(16)30032-5 DB - PRIME DP - Unbound Medicine ER -