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Relationship: 2355

Title

A descriptive phrase which clearly defines the two KEs being considered and the sequential relationship between them (i.e., which is upstream, and which is downstream). More help

Bradykinin, activated leads to Hypofibrinolysis

Upstream event

The causing Key Event (KE) in a Key Event Relationship (KER). More help

Bradykinin, activated

Downstream event

The responding Key Event (KE) in a Key Event Relationship (KER). More help

Hypofibrinolysis

Key Event Relationship Overview

The utility of AOPs for regulatory application is defined, to a large extent, by the confidence and precision with which they facilitate extrapolation of data measured at low levels of biological organisation to predicted outcomes at higher levels of organisation and the extent to which they can link biological effect measurements to their specific causes.Within the AOP framework, the predictive relationships that facilitate extrapolation are represented by the KERs. Consequently, the overall WoE for an AOP is a reflection in part, of the level of confidence in the underlying series of KERs it encompasses. Therefore, describing the KERs in an AOP involves assembling and organising the types of information and evidence that defines the scientific basis for inferring the probable change in, or state of, a downstream KE from the known or measured state of an upstream KE. More help

AOPs Referencing Relationship

AOP Name	Adjacency	Weight of Evidence	Quantitative Understanding	Point of Contact	Author Status	OECD Status
Decreased fibrinolysis and activated bradykinin system leading to hyperinflammation	adjacent			Penny Nymark (send email)	Under development: Not open for comment. Do not cite	Under Development

Taxonomic Applicability

Latin or common names of a species or broader taxonomic grouping (e.g., class, order, family) that help to define the biological applicability domain of the KER.In general, this will be dictated by the more restrictive of the two KEs being linked together by the KER. More help

Term	Scientific Term	Evidence	Link
human	Homo sapiens	High	NCBI

Sex Applicability

An indication of the the relevant sex for this KER. More help

Sex	Evidence
Male	High
Female	High

Life Stage Applicability

An indication of the the relevant life stage(s) for this KER. More help

Key Event Relationship Description

Provides a concise overview of the information given below as well as addressing details that aren’t inherent in the description of the KEs themselves. More help

Bradykinin (BK) plays an important role in the kinin-kallikrein system (KKS) as a regulator of blood pressure and can induce vasodilation, increase blood flow, as well as hypotension. BK is also an important part of the inflammatory process after injury, inducing pain stimulation. Activation of the BK system is associated with vasodilation and vascular leakage, allowing for infiltration of proinflammatory cells such as IL6 ((Hofman et al, 2016).

During SARS-CoV-2 infection, increased activity of kallikrein activates the bradykinin system. Bradykinin is known to stimulate tissue plasminogen activator (tPA), a protein that increases fibrinolysis. However, ACE2 downregulation from SARS-COV-2 infection increases Angiotensin 1 and II (ANG 1 and ANGII), which increases Plasminogen activator inhibitor (PAI-1) levels and decreases tPA levels (Mogielnicki et al, 2014). PAI-1 inhibits the protective effects of tPA/uPA in fibrinolysis, decreasing fibrinolysis. Data shows that both Bradykinin, and subsequently tPA levels and PAI-1 levels increase in COVID-19 patients, but PAI-1 increases at a higher rate than tPA, leading to hypofibrinolysis(Zuo et al, 2021).

Bradykinin, as a result of its role as a vasodilator, increases vascular permeability, which increases levels of proinflammatory mediators such as IL6 (Sprague et al, 2009). These proinflammatory mediators have been found to increase PAI-1 levels, which ultimately leads to hypofibrinolysis(Kang et al, 2020. Rega et al, 2020).

Evidence Collection Strategy

Include a description of the approach for identification and assembly of the evidence base for the KER. For evidence identification, include, for example, a description of the sources and dates of information consulted including expert knowledge, databases searched and associated search terms/strings. Include also a description of study screening criteria and methodology, study quality assessment considerations, the data extraction strategy and links to any repositories/databases of relevant references.Tabular summaries and links to relevant supporting documentation are encouraged, wherever possible. More help

Evidence Supporting this KER

Addresses the scientific evidence supporting KERs in an AOP setting the stage for overall assessment of the AOP. More help

Biological Plausibility

Addresses the biological rationale for a connection between KEupstream and KEdownstream. This field can also incorporate additional mechanistic details that help inform the relationship between KEs, this is useful when it is not practical/pragmatic to represent these details as separate KEs due to the difficulty or relative infrequency with which it is likely to be measured. More help

The biological plausability of this KER is high, as there is a clear relationship between bradykinin activation and fibrinolysis decrease.

Bradykinin system activation increases bradykinin levels. Normally, increased bradykinin levels will cause increased stimulation of bradykinin receptor 2 (BDKRB2), leading to an increase of tissue plasminogen activator (tPA) and urokinase plasminogen activator (uPA) (Garvin et al, 2020). However, in COVID-19 patients, SARS-COV-2 causes ACE2 downregulation and angiotensin 2(ANG II) increase. ANG II is notable because it increase Plasminogen activator inhibitor-1 (PAI-1) and decreases tPA, discovered in a dose study of rats (Mogielnicki et al, 2014) Interestingly, in COVID-19 patients, there is still an increase in tPA and uPA observed, meaning that while ANG II does decrease tPA levels, because bradykinin activation still occurs at a higher rate than ANGII decreases tPA, that means the net effect is higher tPA levels. In COVID-19 patients, we see higher PAI-1 inhibitor levels compared to tPA/uPA levels, and that increased ratio ultimately leads to hypofibrinolysis in COVID-19 patients (Zuo et al, 2021).

Bradykinin also increase vascular permeability, causing increased levels of proinflammatory cytokines such as TNF-∝, C-reactive protein (CRP), and IL6. These cytokines have been found to increase PAI-1 levels, thus leading to hypofibrinolysis (Kang et al, 2020. Rega et al, 2005.).

Empirical Evidence

Provides specific (citable) evidence that supports the idea of a change in the upstream KE (KEupstream) leading to, or being associated with, a subsequent change in the downstream KE (KEdownstream), assuming the perturbation of KEupstream is sufficient. More help

The empirical evidence of this KER is moderate, as there is evidence, i.e COVID-19 patients, that bradykinin activation and fibrinolysis decrease occurs. Evidence however more shows these events happening conccurently rather than happening at a later time, where one event leads to the other event.

stressor	species	study type	dose	KE upstream (bradykininactivation)	KE down stream (fibrinolysis decrease)	description	reference
SARS-COV-2	human	in vivo	Plasma from 118 severe COVID-19 patients and 30 control		Elevations in both PAI-1 and tPA levels were found with strong correlation (r= 0.52, p<0.0001). PAI-1 levels experience higher elevation compared to tPA, leading to hypofibrinolysis.	Observed plasma from 118 COVID-19 patients and measured PAI-1 and tPA levels. Elevations in both PAI-1 and tPA levels were found with strong correlation (r= 0.52, p<0.0001). PAI-1 levels experience higher elevation compared to tPA, leading to hypofibrinolysis. Molecule -> Molecule: SARS-COV-2 -> PAI-1/tPA	Zuo, Y., Warnock, M., Harbaugh, A. et al. Plasma tissue plasminogen activator and plasminogen activator inhibitor-1 in hospitalized COVID-19 patients. Sci Rep 11, 1580 (2021). https://doi.org/10.1038/s41598-020-80010-z
SARS-COV-2	human	in vivo	9 BAL samples of critically ill COVID-19 patients and 40 control	Bradykinin(BK) receptors BDKRB1 and BDKRB2 are highly upregulated in COVID-19 patients vs non-existent in control. BK precursor kininogen and all kallikreins are undetected in controls but expressed in COVID-19 BAL. High downregulation of SERPING1 gene, causing an increase in BK.		The observation of 9 BAL samples of COVID-19 patients finds upregulation of bradykinin receptors 1 and 2, leading to an increase in bradykinin levels and an increase in tPA/uPA levels Molecule -> Molecule: SARS-COV-2 -> BDKRB1/BDKRB2 -> BK ->tPA/uPA	Garvin, M.R.; Alvarez, C.; Miller, J.I.; Prates, E.T.; Walker, A.M.; Amos, B.K.; Mast, A.E.; Justice, A.; Aronow, B.; Jacobson, D. A mechanistic model and therapeutic interventions for COVID-19 involving a RAS-mediated bradykinin storm. eLife 2020, 9.
Angiotensin (1-9)	Male Wistar rats (180–200 g)	In vivo	Ang-(1–9) in doses of 200 (n = 10),400 (n = 13),800 (n = 12) and 1600 pmol/kg/min (n = 13)		Increased PAI-1 levels while decreasing tPA levels	Dose of ANG1-9 in rats find increased PAI-1 levels and decreased tPA levels, leading to hypofibrinolysis	Mogielnicki A, Kramkowski K, Hermanowicz JM, Leszczynska A, Przyborowski K, Buczko W. Angiotensin-(1-9) enhances stasis-induced venous thrombosis in the rat because of the impairment of fibrinolysis. J Renin Angiotensin Aldosterone Syst. 2014 Mar;15(1):13-21. doi: 10.1177/1470320313498631. Epub 2013 Jul 24. PMID: 23884911.
SARS-COV-2	human		Review article	ACE2 downregulation leads to bradykinin receptor binding, causing activation of bradykinin system	ACE2 downregulation by SARS-COV-2 causes increased ANG1-9 which upregulates PAI-1 inhibitor, leading to hypofibrinolysis	Discusses ACE2 downregulation as a result of SARS-COV-2, leading to increased Ang II and ANG1-9. Angiotensin II upregulates PAI-1 and breaks down tPA.	Bernard I, Limonta D, Mahal LK, Hobman TC. Endothelium Infection and Dysregulation by SARS-CoV-2: Evidence and Caveats in COVID-19. Viruses. 2021; 13(1):29. https://doi.org/10.3390/v13010029
SiL6R	Human endothelial cells	In vivo	20 ng/mL of IL6 and 50/100 ng/mL of SIL6R	Bradykinin activation induces proinflammatory mediator level increase thru vasodilation	SIL6R and ILl6 treatment together (IL6 trans signaling) causes increase of PAI-1 In COVID-19 patients, blockade of IL6 with tocilizumab caused PAI-1 levels to decrease.	Bradykinin is pre-established as a vasodilator that increases proinflammatory cytokine levels. Patients of all stressors had significantly higher proinflammatory cytokine levels than the controls. Study into endothelial cells finds that proinflammatory cytokine levels increase significantly when treated with IL6 and soluble IL6R (IL6 trans signaling), also increased include PAI-1 levels	Kang S, Tanaka T, Inoue H, Ono C, Hashimoto S, Kioi Y, Matsumoto H, Matsuura H, Matsubara T, Shimizu K, Ogura H, Matsuura Y, Kishimoto T. IL-6 trans-signaling induces plasminogen activator inhibitor-1 from vascular endothelial cells in cytokine release syndrome. Proc Natl Acad Sci U S A. 2020 Sep 8;117(36):22351-22356. doi: 10.1073/pnas.2010229117. Epub 2020 Aug 21. PMID: 32826331; PMCID: PMC7486751.
Adipose tissue	IL6	In vivo	100 ng/mL		IL6 levels, increased when bradykinin activation occurs. n subcutaneous and visceral adipose tissue, IL6 increased PAI-1 levels up to 3.5 fold. Dose dependent response found with lower dose (0.1, 1) that visceral adipose tissue had higher PAI-1 levels than subcutaneous. Higher dose (10,100) had relatively equal PAI-1 levels.		Rega, G et al. (2005, April 19). Inflammatory cytokines interleukin-6 and oncostatin m induce plasminogen activator inhibitor-1 in human adipose tissue. Circulation. Retrieved January 19, 2022, from https://www.ahajournals.org/doi/full/10.1161/01.CIR.0000161823.55935.BE

Uncertainties and Inconsistencies

Addresses inconsistencies or uncertainties in the relationship including the identification of experimental details that may explain apparent deviations from the expected patterns of concordance. More help

While the evidence connecting bradykinin activation and fibrinolysis decrease is evident, a direct relationship where bradykinin activation leads to fibrinolysis decrease is harder to establish. One of the outcomes of bradykinin runs opposite to fibrinolysis decrease, as bradykinin increases tPA levels where hypofibrinolysis decreases tPA levels as a result of PAI-1 increase. Without a stressor that affects PAI-1 levels more drastically than bradykinin affects tPA levels, such as SARS-COV-2, this relationship would not be possible.

Known modulating factors

This table captures specific information on the MF, its properties, how it affects the KER and respective references.1.) What is the modulating factor? Name the factor for which solid evidence exists that it influences this KER. Examples: age, sex, genotype, diet 2.) Details of this modulating factor. Specify which features of this MF are relevant for this KER. Examples: a specific age range or a specific biological age (defined by...); a specific gene mutation or variant, a specific nutrient (deficit or surplus); a sex-specific homone; a certain threshold value (e.g. serum levels of a chemical above...) 3.) Description of how this modulating factor affects this KER. Describe the provable modification of the KER (also quantitatively, if known). Examples: increase or decrease of the magnitude of effect (by a factor of...); change of the time-course of the effect (onset delay by...); alteration of the probability of the effect; increase or decrease of the sensitivity of the downstream effect (by a factor of...) 4.) Provision of supporting scientific evidence for an effect of this MF on this KER. Give a list of references. More help

SARS-COV-2 is shown to be a modulating factor as Bradykinin activation normally causes increased tPA/uPA, which would cause fibrinolysis, not hypofibrinolysis.

Quantitative Understanding of the Linkage

Captures information that helps to define how much change in the upstream KE, and/or for how long, is needed to elicit a detectable and defined change in the downstream KE. More help

Understanding quantitative linkage is difficult as the global pandemic caused by SARS-COV-2 is still a major factor in the world, however it is clear that individuals more severely affected by SARS-COV-2 (hospitalizations) result in higher change of fibrinolysis decrease as a result of bradykinin activation. Perturbation of the RAAS system where ANGII levels are greater than ANGI levels cause this relationship. What specifically causes more severe SARS-COV-2 reactions is yet to be understood.

Response-response Relationship

Provides sources of data that define the response-response relationships between the KEs. More help

Time-scale

Information regarding the approximate time-scale of the changes in KEdownstream relative to changes in KEupstream (i.e., do effects on KEdownstream lag those on KEupstream by seconds, minutes, hours, or days?). More help

Known Feedforward/Feedback loops influencing this KER

Define whether there are known positive or negative feedback mechanisms involved and what is understood about their time-course and homeostatic limits. More help

Domain of Applicability

A free-text section of the KER description that the developers can use to explain their rationale for the taxonomic, life stage, or sex applicability structured terms. More help

References

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

Bernard, I.; Limonta, D.; Mahal, L.K.; Hobman, T.C. Endothelium Infection and Dysregulation by SARS-CoV-2: Evidence and Caveats in COVID-19. Viruses 2021, 13, 29. https://doi.org/10.3390/v13010029
Kang S, Tanaka T, Inoue H, Ono C, Hashimoto S, Kioi Y, Matsumoto H, Matsuura H, Matsubara T, Shimizu K, Ogura H, Matsuura Y, Kishimoto T. IL-6 trans-signaling induces plasminogen activator inhibitor-1 from vascular endothelial cells in cytokine release syndrome. Proc Natl Acad Sci U S A. 2020 Sep 8;117(36):22351-22356. doi: 10.1073/pnas.2010229117. Epub 2020 Aug 21. PMID: 32826331; PMCID: PMC7486751
Garvin, M.R.; Alvarez, C.; Miller, J.I.; Prates, E.T.; Walker, A.M.; Amos, B.K.; Mast, A.E.; Justice, A.; Aronow, B.; Jacobson, D. A mechanistic model and therapeutic interventions for COVID-19 involving a RAS-mediated bradykinin storm. eLife 2020, 9.
Hofman, Z., de Maat, S., Hack, C.E. et al. Bradykinin: Inflammatory Product of the Coagulation System. Clinic Rev Allerg Immunol 51, 152–161 (2016). https://doi.org/10.1007/s12016-016-8540-0
Mogielnicki A, Kramkowski K, Hermanowicz JM, Leszczynska A, Przyborowski K, Buczko W. Angiotensin-(1-9) enhances stasis-induced venous thrombosis in the rat because of the impairment of fibrinolysis. J Renin Angiotensin Aldosterone Syst. 2014 Mar;15(1):13-21. doi: 10.1177/1470320313498631. Epub 2013 Jul 24. PMID: 23884911
Rega, G.C. Kaun, T.W. Weiss, S. Demyanets, G. Zorn, S.P. Kastl, S. Steiner, D. Seidinger, C.W. Kopp, M. Frey, R. Roehle, G. Maurer, K. Huber, and J. Wojta (2005, April 19). Inflammatory cytokines interleukin-6 and oncostatin m induce plasminogen activator inhibitor-1 in human adipose tissue. Circulation. Retrieved January 19, 2022, from https://www.ahajournals.org/doi/full/10.1161/01.CIR.0000161823.55935.BE
Silhol, F.; Sarlon, G.; Deharo, J.-C.; Vaïsse, B. Downregulation of ACE2 induces overstimulation of the renin–angiotensin system in COVID-19: Should we block the renin–angiotensin system? Hypertens. Res. 2020, 43, 854–856
Sprague AH, Khalil RA. Inflammatory cytokines in vascular dysfunction and vascular disease. Biochem Pharmacol. 2009;78(6):539-552. doi:10.1016/j.bcp.2009.04.029

9. Zuo, Y., Warnock, M., Harbaugh, A. et al. Plasma tissue plasminogen activator and plasminogen activator inhibitor-1 in hospitalized COVID-19 patients. Sci Rep 11, 1580 (2021). https://doi.org/10.1038/s41598-020-80010-z