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AOP: 31

Title

A descriptive phrase which references both the Molecular Initiating Event and Adverse Outcome.It should take the form “MIE leading to AO”. For example, “Aromatase inhibition leading to reproductive dysfunction” where Aromatase inhibition is the MIE and reproductive dysfunction the AO. In cases where the MIE is unknown or undefined, the earliest known KE in the chain (i.e., furthest upstream) should be used in lieu of the MIE and it should be made clear that the stated event is a KE and not the MIE. More help

Oxidation of iron in hemoglobin leading to hematotoxicity

Short name

A name that succinctly summarises the information from the title. This name should not exceed 90 characters. More help

Hemoglobin oxidation leading to hematotoxicity

The current version of the Developer's Handbook will be automatically populated into the Handbook Version field when a new AOP page is created.Authors have the option to switch to a newer (but not older) Handbook version any time thereafter. More help

Handbook Version v1.0

Graphical Representation

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Click to download graphical representation template Explore AOP in a Third Party Tool

Authors

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Mitchell Wilbanks, Kurt Gust, Youping Deng, Sharon Meyer, and Edward Perkins

Point of Contact: Mitchell Wilbanks, Mitchell.S.Wilbanks@usace.army.mil

Point of Contact

The user responsible for managing the AOP entry in the AOP-KB and controlling write access to the page by defining the contributors as described in the next section. More help

Cataia Ives (email point of contact)

Contributors

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Cataia Ives

Coaches

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OECD Information Table

Provides users with information concerning how actively the AOP page is being developed and whether it is part of the OECD Workplan and has been reviewed and/or endorsed. OECD Project: Assigned upon acceptance onto OECD workplan. This project ID is managed and updated (if needed) by the OECD. OECD Status: For AOPs included on the OECD workplan, ‘OECD status’ tracks the level of review/endorsement of the AOP . This designation is managed and updated by the OECD. Journal-format Article: The OECD is developing co-operation with Scientific Journals for the review and publication of AOPs, via the signature of a Memorandum of Understanding. When the scientific review of an AOP is conducted by these Journals, the journal review panel will review the content of the Wiki. In addition, the Journal may ask the AOP authors to develop a separate manuscript (i.e. Journal Format Article) using a format determined by the Journal for Journal publication. In that case, the journal review panel will be required to review both the Wiki content and the Journal Format Article. The Journal will publish the AOP reviewed through the Journal Format Article. OECD iLibrary published version: OECD iLibrary is the online library of the OECD. The version of the AOP that is published there has been endorsed by the OECD. The purpose of publication on iLibrary is to provide a stable version over time, i.e. the version which has been reviewed and revised based on the outcome of the review. AOPs are viewed as living documents and may continue to evolve on the AOP-Wiki after their OECD endorsement and publication. More help

OECD Project #	OECD Status	Reviewer's Reports	Journal-format Article	OECD iLibrary Published Version
1.16	Under Development

This AOP was last modified on May 26, 2024 20:39

Revision dates for related pages

Page	Revision Date/Time
N/A, Parent compound is converted to the reactive metabolite and forms free radicals leading to oxidation of heme iron(II) in hemoglobin to iron(III)	December 03, 2016 16:37
Altered regulation, Alpha hemoglobin	September 16, 2017 10:14
Propagation, Oxidative stress	September 16, 2017 10:14
Damaging, Red blood cells; hemolysis	September 16, 2017 10:14
Formation, Formation of hemoglobin adducts	September 16, 2017 10:14
Down Regulation, Gulcose-6-phosphate dehydrogenase	September 16, 2017 10:14
Increase, RBC congestion in liver	September 16, 2017 10:14
Increase, Liver and splenic hemosiderosis	September 16, 2017 10:14
N/A, Methemoglobinemia, decreased hemoglobin, hematocrit, red blood cell number	September 16, 2017 10:14
N/A, Cyanosis occurs	December 03, 2016 16:33
N/A, Parent compound is converted to the reactive metabolite and forms free radicals leadin leads to Propagation, Oxidative stress	December 03, 2016 16:37
N/A, Parent compound is converted to the reactive metabolite and forms free radicals leadin leads to Damaging, Red blood cells; hemolysis	December 03, 2016 16:37
N/A, Parent compound is converted to the reactive metabolite and forms free radicals leadin leads to Formation, Formation of hemoglobin adducts	December 03, 2016 16:37
Damaging, Red blood cells; hemolysis leads to Increase, RBC congestion in liver	December 03, 2016 16:37
Damaging, Red blood cells; hemolysis leads to N/A, Methemoglobinemia, decreased hemoglobin, hematocrit, red blood cell number	December 03, 2016 16:37
Damaging, Red blood cells; hemolysis leads to Increase, Liver and splenic hemosiderosis	December 03, 2016 16:37
Propagation, Oxidative stress leads to Down Regulation, Gulcose-6-phosphate dehydrogenase	December 03, 2016 16:37
N/A, Parent compound is converted to the reactive metabolite and forms free radicals leadin leads to Altered regulation, Alpha hemoglobin	December 03, 2016 16:37
N/A, Methemoglobinemia, decreased hemoglobin, hematocrit, red blood cell number leads to N/A, Cyanosis occurs	December 03, 2016 16:37
Increase, RBC congestion in liver leads to N/A, Methemoglobinemia, decreased hemoglobin, hematocrit, red blood cell number	December 03, 2016 16:37
Propagation, Oxidative stress leads to Damaging, Red blood cells; hemolysis	December 03, 2016 16:37
Increase, Liver and splenic hemosiderosis leads to N/A, Methemoglobinemia, decreased hemoglobin, hematocrit, red blood cell number	December 03, 2016 16:37

Abstract

A concise and informative summation of the AOP under development that can stand-alone from the AOP page. The aim is to capture the highlights of the AOP and its potential scientific and regulatory relevance. More help

Studies have shown that aniline, 2,4,6-trinitrotoluene (TNT) and 2,4-dinitrotoluene (2,4-DNT) are converted to the reactive metabolite and form free radicals leading to oxidization of heme Iron(II) in hemoglobin to Iron(III), a molecular initiating event. Damage then occurs to red blood cells (RBCs) and methemoglobinemia ensues which is characterized by reduced RBCs, hemoglobin concentration, and Heinz body formation (Ellis et al. 1985, Lee et al. 1976, 1978, Hazleton Laboratories 1977, 1982, Kozuka et al. 1978, 1979, Bolt et al. 2006). The adverse outcome due to such hematological effects is cyanosis with possible death if methemoglobin levels become severe. Hemoglobin adducts are also formed by these chemicals (Sabbioni et al. 2006). Sinusoidal congestion was noted in animals who were exposed to 2,4-DNT or 2,6-DNT (Deng et al. 2011) while hemosiderosis was reported in another study involving DNT (Lee et al. 1978) and in aniline studies. A compensatory response to possible anemic effects has been observed in animals including increased peripheral reticulocytes (Deng et al. 2011) and induction of genes associated with heme biosynthesis (CPOX and UROS) (Rawat et al. 2010). Oxidative stress is also induced upon this interaction with the RBC which may lead to DNA damage and cell death to not only the RBC but other cells such as hepatocytes (Deng et al. 2011). Glucose-6-phosphate dehydrogenase (G6pd) was found to be significantly down-regulated in animals treated with 2,4-DNT for 14 d which leads to decreased levels of NADPH, a coenzyme used to properly maintain glutathione levels and therefore protect cells, especially RBC, from oxidative damage (Wilbanks, et al., unpublished observations). In response to increased oxidative stress, protective mechanisms such as the Nrf2 mediated oxidative stress response may be induced (Deng et al. 2011). While this AOP specifically shows effects of 2,4-DNT and 2,6-DNT, the principal adverse pathways of oxidation of Fe(II) to Fe(III) leading to methemoglobinemia and its downsteam effects and oxidative stress formation leading to its downstream effects are shared with the more well characterized structurally similar compound group of N-hydroxyl anilines.

AOP Development Strategy

Context

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Strategy

Provides a description of the approaches to the identification, screening and quality assessment of the data relevant to identification of the key events and key event relationships included in the AOP or AOP network.This information is important as a basis to support the objective/envisaged application of the AOP by the regulatory community and to facilitate the reuse of its components. Suggested content includes a rationale for and description of the scope and focus of the data search and identification strategy/ies including the nature of preliminary scoping and/or expert input, the overall literature screening strategy and more focused literature surveys to identify additional information (including e.g., key search terms, databases and time period searched, any tools used). More help

Summary of the AOP

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Events:

Molecular Initiating Events (MIE)

An MIE is a specialised KE that represents the beginning (point of interaction between a prototypical stressor and the biological system) of an AOP. More help

Key Events (KE)

A measurable event within a specific biological level of organisation. More help

Adverse Outcomes (AO)

An AO is a specialized KE that represents the end (an adverse outcome of regulatory significance) of an AOP. More help

Type	Event ID	Title	Short name

MIE

213

N/A, Parent compound is converted to the reactive metabolite and forms free radicals leading to oxidation of heme iron(II) in hemoglobin to iron(III)

N/A, Parent compound is converted to the reactive metabolite and forms free radicals leadin

KE	21	Altered regulation, Alpha hemoglobin	Altered regulation, Alpha hemoglobin
KE	211	Propagation, Oxidative stress	Propagation, Oxidative stress
KE	250	Damaging, Red blood cells; hemolysis	Damaging, Red blood cells; hemolysis
KE	118	Formation, Formation of hemoglobin adducts	Formation, Formation of hemoglobin adducts
KE	131	Down Regulation, Gulcose-6-phosphate dehydrogenase	Down Regulation, Gulcose-6-phosphate dehydrogenase
KE	246	Increase, RBC congestion in liver	Increase, RBC congestion in liver
KE	161	Increase, Liver and splenic hemosiderosis	Increase, Liver and splenic hemosiderosis
KE	173	N/A, Methemoglobinemia, decreased hemoglobin, hematocrit, red blood cell number	N/A, Methemoglobinemia, decreased hemoglobin, hematocrit, red blood cell number

321

N/A, Cyanosis occurs

Relationships Between Two Key Events (Including MIEs and AOs)

This table summarizes all of the KERs of the AOP and is populated in the AOP-Wiki as KERs are added to the AOP.Each table entry acts as a link to the individual KER description page. More help

Title	Adjacency	Evidence	Quantitative Understanding

N/A, Parent compound is converted to the reactive metabolite and forms free radicals leadin leads to Propagation, Oxidative stress	adjacent	Moderate
N/A, Parent compound is converted to the reactive metabolite and forms free radicals leadin leads to Damaging, Red blood cells; hemolysis	adjacent	High
N/A, Parent compound is converted to the reactive metabolite and forms free radicals leadin leads to Formation, Formation of hemoglobin adducts	adjacent	High
Damaging, Red blood cells; hemolysis leads to Increase, RBC congestion in liver	adjacent	Moderate
Damaging, Red blood cells; hemolysis leads to N/A, Methemoglobinemia, decreased hemoglobin, hematocrit, red blood cell number	adjacent	High
Damaging, Red blood cells; hemolysis leads to Increase, Liver and splenic hemosiderosis	adjacent	High
Propagation, Oxidative stress leads to Down Regulation, Gulcose-6-phosphate dehydrogenase	adjacent	Low
N/A, Methemoglobinemia, decreased hemoglobin, hematocrit, red blood cell number leads to N/A, Cyanosis occurs	adjacent	High
Increase, RBC congestion in liver leads to N/A, Methemoglobinemia, decreased hemoglobin, hematocrit, red blood cell number	adjacent	Moderate
Propagation, Oxidative stress leads to Damaging, Red blood cells; hemolysis	adjacent	High
Increase, Liver and splenic hemosiderosis leads to N/A, Methemoglobinemia, decreased hemoglobin, hematocrit, red blood cell number	adjacent	Moderate

N/A, Parent compound is converted to the reactive metabolite and forms free radicals leadin leads to Altered regulation, Alpha hemoglobin

non-adjacent

Low

Network View

This network graphic is automatically generated based on the information provided in the MIE(s), KEs, AO(s), KERs and Weight of Evidence (WoE) summary tables. The width of the edges representing the KERs is determined by its WoE confidence level, with thicker lines representing higher degrees of confidence. This network view also shows which KEs are shared with other AOPs. More help

Prototypical Stressors

A structured data field that can be used to identify one or more “prototypical” stressors that act through this AOP. Prototypical stressors are stressors for which responses at multiple key events have been well documented. More help

Life Stage Applicability

The life stage for which the AOP is known to be applicable. More help

Taxonomic Applicability

Latin or common names of a species or broader taxonomic grouping (e.g., class, order, family) can be selected.In many cases, individual species identified in these structured fields will be those for which the strongest evidence used in constructing the AOP was available. More help

Term	Scientific Term	Evidence	Link
Mus musculus	Mus musculus	High	NCBI
Rattus norvegicus	Rattus norvegicus	High	NCBI

Sex Applicability

The sex for which the AOP is known to be applicable. More help

Overall Assessment of the AOP

Addressess the relevant biological domain of applicability (i.e., in terms of taxa, sex, life stage, etc.) and Weight of Evidence (WoE) for the overall AOP as a basis to consider appropriate regulatory application (e.g., priority setting, testing strategies or risk assessment). More help

This AOP is constructed using data from human, rat, mouse, avian, and fish based studies.

Domain of Applicability

Addressess the relevant biological domain(s) of applicability in terms of sex, life-stage, taxa, and other aspects of biological context. More help

Essentiality of the Key Events

The essentiality of KEs can only be assessed relative to the impact of manipulation of a given KE (e.g., experimentally blocking or exacerbating the event) on the downstream sequence of KEs defined for the AOP. Consequently, evidence supporting essentiality is assembled on the AOP page, rather than on the independent KE pages that are meant to stand-alone as modular units without reference to other KEs in the sequence. The nature of experimental evidence that is relevant to assessing essentiality relates to the impact on downstream KEs and the AO if upstream KEs are prevented or modified. This includes: Direct evidence: directly measured experimental support that blocking or preventing a KE prevents or impacts downstream KEs in the pathway in the expected fashion. Indirect evidence: evidence that modulation or attenuation in the magnitude of impact on a specific KE (increased effect or decreased effect) is associated with corresponding changes (increases or decreases) in the magnitude or frequency of one or more downstream KEs. More help

Evidence Assessment

Addressess the biological plausibility, empirical support, and quantitative understanding from each KER in an AOP. More help

Known Modulating Factors

Modulating factors (MFs) may alter the shape of the response-response function that describes the quantitative relationship between two KES, thus having an impact on the progression of the pathway or the severity of the AO.The evidence supporting the influence of various modulating factors is assembled within the individual KERs. More help

Quantitative Understanding

Optional field to provide quantitative weight of evidence descriptors. More help

Considerations for Potential Applications of the AOP (optional)

Addressess potential applications of an AOP to support regulatory decision-making.This may include, for example, possible utility for test guideline development or refinement, development of integrated testing and assessment approaches, development of (Q)SARs / or chemical profilers to facilitate the grouping of chemicals for subsequent read-across, screening level hazard assessments or even risk assessment. More help

References

List of the literature that was cited for this AOP. More help

Bolt HM, Degen GH, Dorn SB, Plöttner S, Harth V (2006) Genotoxicity and potential carcinogenicity of 2,4,6-TNT trinitrotoluene: structural and toxicological considerations. Reviews on environmental health. Oct-Dec; 21(4):217-28.

Deng Y, Meyer SA, Guan X, Escalon BL, Ai J, et al. (2011) Analysis of Common and Specific Mechanisms of Liver Function Affected by Nitrotoluene Compounds. PLoS ONE. 6(2): e14662.

Ellis HV, Hong CB, Lee CC, et al. 1985. Subchronic and chronic toxicity studies of 2,4-dinitrotoluene. Part I. Beagle dog. J Am Co11 Toxicol. 4:233-242.

Jones, C.R., Liu, Y., Sepai, O., Yan, H., and Sabbioni, G. (2005). Hemoglobin adducts in workers exposed to nitrotoluenes. Carcinogenesis. 26(1):133-143.

Kozuka H, Mori M., Katayama K, Matsuhashi T, Miyahara T, Mori Y, and Nagahara S. 1978. Studies on the metabolism and toxicity of dinitrotoluenes-Metabolism of dinitrotoluenes by Rhodotorula glutinis and rat liver homogenate. Eisei Kagaku, 24: 252-259.

Kozuka H, Mori M, and Yoshifumi, N. 1979. Studies on the metabolism and toxicity of dinitrotoluenes: Toxicological study of 2,4-dinitrotoluene (2,4-DNT) in rats in long term feeding. The Journal of Toxicological Sciences. 4:221-228.

La, D.K. and Froines, J.R. (1992). Comparison of DNA adduct formation between 2,4 and 2,6-dintirotoluene by 32P-postlabelling analysis. Archives of Toxicology. 66(9):633-640.

Lee CC, Ellis HV, Kowalski JJ, et al. 1976. Mammalian toxicity of munitions compounds. Phase II: Effects of multiple doses. Part IIh 2,6-Dinitrotoluene. Progress report no. 4. Midwest Research Institute Project no. 3900-B. Contract no. DAMD-17-74-C-4073. From ASTDR.

Lee CC, Ellis HV, Kowalski JJ, et al. 1978. Mammalian toxicity of munitions compounds. Phase II: Effects of multiple doses. Part Il: 2,4-Dinitrotoluene. Progress report No. 3. Midwest Research Institute, Kansas City, MO. Contract no. DAMD 17-74-C-4073. From ASTDR.

Hazleton Laboratories. 1977. A thirty-day toxicology study in Fischer-344 rats given dinitrotoluene, technical grade. Full report. Submitted to Chemical Industry Institute of Toxicology, Research Triangle Park, NC.

Hazleton Laboratories. 1982. 104-week chronic study in rats. Dinitrotoluene. Final report Volume I of II. Submitted to Chemical Industry Institute of Toxicology, Research Triangle Park, NC.

Rawat A, Gust KA, Deng Y, Garcia-Reyero N, Quinn MJ Jr, Johnson MS, Indest KJ, Elasri MO, Perkins EJ. From raw materials to validated system: the construction of a genomic library and microarray to interpret systemic perturbations in Northern bobwhite. Physiol Genomics. 42: 219–235, 2010.

Sabbioni G, Jones CR, Sepai O, et al. 2006. Biomarkers of exposure, effect, and susceptibility in workers exposed to nitrotoluenes. Cancer Epidemiol Biomarkers. Prev 15(3):559-66.

Wintz H, Yoo LJ, Loguinov A, Wu Y, Steevens JA, Holland RD, Beger RD, Perkins EJ, Hughes O, Vulpe CD. Gene expression profiles in fathead minnow exposed to 2,4-DNT: correlation with toxicity in mammals. Toxicol Sci. 94: 71–82, 2006.