1
|
Buhler CK, Terry RS, Link KG, Adler FR. Do mechanisms matter? Comparing cancer treatment strategies across mathematical models and outcome objectives. Math Biosci Eng 2021; 18:6305-6327. [PMID: 34517535 PMCID: PMC10625481 DOI: 10.3934/mbe.2021315] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
When eradication is impossible, cancer treatment aims to delay the emergence of resistance while minimizing cancer burden and treatment. Adaptive therapies may achieve these aims, with success based on three assumptions: resistance is costly, sensitive cells compete with resistant cells, and therapy reduces the population of sensitive cells. We use a range of mathematical models and treatment strategies to investigate the tradeoff between controlling cell populations and delaying the emergence of resistance. These models extend game theoretic and competition models with four additional components: 1) an Allee effect where cell populations grow more slowly at low population sizes, 2) healthy cells that compete with cancer cells, 3) immune cells that suppress cancer cells, and 4) resource competition for a growth factor like androgen. In comparing maximum tolerable dose, intermittent treatment, and adaptive therapy strategies, no therapeutic choice robustly breaks the three-way tradeoff among the three therapeutic aims. Almost all models show a tight tradeoff between time to emergence of resistant cells and cancer cell burden, with intermittent and adaptive therapies following identical curves. For most models, some adaptive therapies delay overall tumor growth more than intermittent therapies, but at the cost of higher cell populations. The Allee effect breaks these relationships, with some adaptive therapies performing poorly due to their failure to treat sufficiently to drive populations below the threshold. When eradication is impossible, no treatment can simultaneously delay emergence of resistance, limit total cancer cell numbers, and minimize treatment. Simple mathematical models can play a role in designing the next generation of therapies that balance these competing objectives.
Collapse
Affiliation(s)
- Cassidy K. Buhler
- Department of Decision Sciences and MIS, Drexel University, 3220 Market St, Philadelphia, PA 19104, USA
- Department of Mathematics, University of Utah, 155 S 1400 E, Salt Lake City, UT 84112, USA
| | - Rebecca S. Terry
- Department of Mathematics, University of Utah, 155 S 1400 E, Salt Lake City, UT 84112, USA
- Department of Mathematics, Computer Science and Statistics, St. Lawrence University, 23 Romoda Drive, Canton, NY 13617, USA
| | - Kathryn G. Link
- Department of Mathematics, University of California, Davis, One Shields Avenue, CA 95616, USA
| | - Frederick R. Adler
- Department of Mathematics, University of Utah, 155 S 1400 E, Salt Lake City, UT 84112, USA
- School of Biological Sciences, University of Utah, 257 S 1400 E, Salt Lake City, UT 84112, USA
| |
Collapse
|
2
|
Link KG, Sorrells MG, Danes NA, Neeves KB, Leiderman K, Fogelson AL. A MATHEMATICAL MODEL OF PLATELET AGGREGATION IN AN EXTRAVASCULAR INJURY UNDER FLOW. Multiscale Model Simul 2020; 18:1489-1524. [PMID: 33867873 PMCID: PMC8051825 DOI: 10.1137/20m1317785] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We present the first mathematical model of flow-mediated primary hemostasis in an extravascular injury which can track the process from initial deposition to occlusion. The model consists of a system of ordinary differential equations (ODEs) that describe platelet aggregation (adhesion and cohesion), soluble-agonist-dependent platelet activation, and the flow of blood through the injury. The formation of platelet aggregates increases resistance to flow through the injury, which is modeled using the Stokes-Brinkman equations. Data from analogous experimental (microfluidic flow) and partial differential equation models informed parameter values used in the ODE model description of platelet adhesion, cohesion, and activation. This model predicts injury occlusion under a range of flow and platelet activation conditions. Simulations testing the effects of shear and activation rates resulted in delayed occlusion and aggregate heterogeneity. These results validate our hypothesis that flow-mediated dilution of activating chemical adenosine diphosphate hinders aggregate development. This novel modeling framework can be extended to include more mechanisms of platelet activation as well as the addition of the biochemical reactions of coagulation, resulting in a computationally efficient high throughput screening tool of primary and secondary hemostasis.
Collapse
Affiliation(s)
- Kathryn G Link
- Department of Mathematics, University of California, Davis, Davis, CA 95616 USA
| | - Matthew G Sorrells
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO 80401 USA
| | - Nicholas A Danes
- Department of Applied Mathematics and Statistics, Colorado School of Mines, Golden, CO 80401 USA
| | - Keith B Neeves
- Departments of Bioengineering and Pediatrics, Hemophilia and Thrombosis Center, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO 80401 USA
| | - Karin Leiderman
- Department of Applied Mathematics and Statistics, Colorado School of Mines, Golden, CO 80401 USA
| | - Aaron L Fogelson
- Department of Mathematics, University of California, Davis, Davis, CA 95616 USA
- Department of Biomedical Engineering University of Utah, Salt Lake City, UT 84112 USA
| |
Collapse
|
3
|
Abstract
Bleeding frequency and severity within clinical categories of hemophilia A are highly variable and the origin of this variation is unknown. Solving this mystery in coagulation requires the generation and analysis of large data sets comprised of experimental outputs or patient samples, both of which are subject to limited availability. In this review, we describe how a computationally driven approach bypasses such limitations by generating large synthetic patient data sets. These data sets were created with a mechanistic mathematical model, by varying the model inputs, clotting factor, and inhibitor concentrations, within normal physiological ranges. Specific mathematical metrics were chosen from the model output, used as a surrogate measure for bleeding severity, and statistically analyzed for further exploration and hypothesis generation. We highlight results from our recent study that employed this computationally driven approach to identify FV (factor V) as a key modifier of thrombin generation in mild to moderate hemophilia A, which was confirmed with complementary experimental assays. The mathematical model was used further to propose a potential mechanism for these observations whereby thrombin generation is rescued in FVIII-deficient plasma due to reduced substrate competition between FV and FVIII for FXa (activated factor X).
Collapse
Affiliation(s)
- Kathryn G Link
- Department of Mathematics, University of California Davis (K.G.L.)
| | - Michael T Stobb
- Department of Mathematics and Computer Science, Coe College, Cedar Rapids, IA (M.T.S.)
| | - Dougald M Monroe
- Department of Medicine, UNC Blood Research Center, University of North Carolina at Chapel Hill (D.M.M.)
| | - Aaron L Fogelson
- Departments of Mathematics and Biomedical Engineering, University of Utah, Salt Lake City (A.L.F.)
| | - Keith B Neeves
- Departments of Bioengineering and Pediatrics, Section of Hematology, Oncology, and Bone Marrow Transplant, Hemophilia and Thrombosis Center, University of Colorado, Denver (K.B.N.)
| | - Suzanne S Sindi
- Department of Applied Mathematics, University of California, Merced (S.S.S.)
| | - Karin Leiderman
- Department of Applied Mathematics and Statistics, Colorado School of Mines, Golden (K.L.)
| |
Collapse
|
4
|
Link KG, Stobb MT, Sorrells MG, Bortot M, Ruegg K, Manco-Johnson MJ, Di Paola JA, Sindi SS, Fogelson AL, Leiderman K, Neeves KB. A mathematical model of coagulation under flow identifies factor V as a modifier of thrombin generation in hemophilia A. J Thromb Haemost 2020; 18:306-317. [PMID: 31562694 PMCID: PMC6994344 DOI: 10.1111/jth.14653] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 09/24/2019] [Indexed: 11/29/2022]
Abstract
BACKGROUND The variability in bleeding patterns among individuals with hemophilia A, who have similar factor VIII (FVIII) levels, is significant and the origins are unknown. OBJECTIVE To use a previously validated mathematical model of flow-mediated coagulation as a screening tool to identify parameters that are most likely to enhance thrombin generation in the context of FVIII deficiency. METHODS We performed a global sensitivity analysis (GSA) on our mathematical model to identify potential modifiers of thrombin generation. Candidates from the GSA were confirmed by calibrated automated thrombography (CAT) and flow assays on collagen-tissue factor (TF) surfaces at a shear rate of 100 per second. RESULTS Simulations identified low-normal factor V (FV) (50%) as the strongest modifier, with additional thrombin enhancement when combined with high-normal prothrombin (150%). Low-normal FV levels or partial FV inhibition (60% activity) augmented thrombin generation in FVIII-inhibited or FVIII-deficient plasma in CAT. Partial FV inhibition (60%) boosted fibrin deposition in flow assays performed with whole blood from individuals with mild and moderate FVIII deficiencies. These effects were amplified by high-normal prothrombin levels in both experimental models. CONCLUSIONS These results show that low-normal FV levels can enhance thrombin generation in hemophilia A. Further explorations with the mathematical model suggest a potential mechanism: lowering FV reduces competition between FV and FVIII for factor Xa (FXa) on activated platelet surfaces (APS), which enhances FVIII activation and rescues thrombin generation in FVIII-deficient blood.
Collapse
Affiliation(s)
- Kathryn G. Link
- Department of Applied Mathematics, University of California, Merced, Merced, CA, USA
| | - Michael T. Stobb
- Department of Mathematics, University of Utah, Salt Lake City, UT, USA
| | - Matthew G. Sorrells
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO, USA
| | - Maria Bortot
- Department of Bioengineering, University of Colorado, Denver | Anschutz Medical Campus, Aurora, CO, USA
| | - Katherine Ruegg
- Hemophilia and Thrombosis Center, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
| | - Marilyn J. Manco-Johnson
- Hemophilia and Thrombosis Center, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
- Department of Pediatrics, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
| | - Jorge A. Di Paola
- Hemophilia and Thrombosis Center, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
- Department of Pediatrics, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
| | - Suzanne S. Sindi
- Department of Mathematics, University of Utah, Salt Lake City, UT, USA
| | - Aaron L. Fogelson
- Department of Applied Mathematics, University of California, Merced, Merced, CA, USA
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA
| | - Karin Leiderman
- Department of Applied Mathematics and Statistics, Colorado School of Mines, Golden, CO, USA
| | - Keith B. Neeves
- Department of Bioengineering, University of Colorado, Denver | Anschutz Medical Campus, Aurora, CO, USA
- Hemophilia and Thrombosis Center, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
- Department of Pediatrics, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA
| |
Collapse
|
5
|
Link KG, Stobb MT, Di Paola J, Neeves KB, Fogelson AL, Sindi SS, Leiderman K. A local and global sensitivity analysis of a mathematical model of coagulation and platelet deposition under flow. PLoS One 2018; 13:e0200917. [PMID: 30048479 PMCID: PMC6062055 DOI: 10.1371/journal.pone.0200917] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 07/04/2018] [Indexed: 11/23/2022] Open
Abstract
The hemostatic response involves blood coagulation and platelet aggregation to stop blood loss from an injured blood vessel. The complexity of these processes make it difficult to intuit the overall hemostatic response without quantitative methods. Mathematical models aim to address this challenge but are often accompanied by numerous parameters choices and thus need to be analyzed for sensitivity to such choices. Here we use local and global sensitivity analyses to study a model of coagulation and platelet deposition under flow. To relate with clinical assays, we measured the sensitivity of three specific thrombin metrics: lag time, maximum relative rate of generation, and final concentration after 20 minutes. In addition, we varied parameters of three different classes: plasma protein levels, kinetic rate constants, and platelet characteristics. In terms of an overall ranking of the model’s sensitivities, we found that the local and global methods provided similar information. Our local analysis, in agreement with previous findings, shows that varying parameters within 50-150% of baseline values, in a one-at-a-time (OAT) fashion, always leads to significant thrombin generation in 20 minutes. Our global analysis gave a different and novel result highlighting groups of parameters, still varying within the normal 50-150%, that produced little or no thrombin in 20 minutes. Variations in either plasma levels or platelet characteristics, using either OAT or simultaneous variations, always led to strong thrombin production and overall, relatively low output variance. Simultaneous variation in kinetics rate constants or in a subset of all three parameter classes led to the highest overall output variance, incorporating instances with little to no thrombin production. The global analysis revealed multiple parameter interactions in the lag time and final concentration leading to relatively high variance; high variance was also observed in the thrombin generation rate, but parameters attributed to that variance acted independently and additively.
Collapse
Affiliation(s)
- Kathryn G. Link
- Department of Bioengineering, University of Utah, Salt Lake City, UT, United States of America
| | - Michael T. Stobb
- Department of Applied Mathematics, University of California Merced, Merced, CA, United States of America
| | - Jorge Di Paola
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States of America
| | - Keith B. Neeves
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States of America
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO, United States of America
| | - Aaron L. Fogelson
- Department of Mathematics, University of Utah, Salt Lake City, UT, United States of America
- Department of Bioengineering, University of Utah, Salt Lake City, UT, United States of America
| | - Suzanne S. Sindi
- Department of Applied Mathematics, University of California Merced, Merced, CA, United States of America
| | - Karin Leiderman
- Department of Applied Mathematics and Statistics, Colorado School of Mines, Golden, CO, United States of America
- * E-mail:
| |
Collapse
|