Active, three-dimensional stomach deformation - experiment and simulation (DFG SI841/12-1)
In this project we cooperate with: Prof. Markus Böl (TU-Braunschweig).
The stomach is a central organ of vertebrates and imposes, based on its extreme deformation, special requirements on the entire stomach tissue and especially on the active smooth muscle tissue. Although there are many dysfunctions combined with tissue changes, mechanical analyses are rare. Consequently, the main aim of this project is the development and validation of an electro-chemo-mechanical model based on experimental investigations on the porcine stomach.
For the development and validation of the model, four steps are scheduled, featuring a tight linkage between experiment and modelling. Thereby, experiments on domestic pigs will be performed, as structure and contraction behaviour are similar to those of humans. Basic requirement for the model generation is the development of the used techniques (I). These are the detection of the three-dimensional deformation as well as of the activation potential propagation at the stomach’s surface. Based on an optical measurement technique, developed by the applicants for the recording of skeletal muscle deformation, in this project a procedure will be established to measure the stomach geometry in physiological saline solution. Further, surface electrodes for the measurement of the propagation of the action potential at the stomach’s surface will be developed. The first experimental step includes analyses of tissue strips (II). In order to capture local differences of the stomach’s structure, preparations will be dissected at defined positions of the stomach wall. Thus, the layer specific architecture as well as its active and passive characteristics can be determined. These data are used for an interim validation and the parameter identification of the electro-chemo-mechanical model. Based on active and passive analyses on the whole stomach (III) its capacity, the pressure-volume dependence, the three-dimensional deformation and the propagation of the action potential at the stomach’s surface will be determined. In a final step these additional data of the whole stomach are used to validate the whole model (IV).
The model developed in this project can be seen to be a compensational method for animal models and, based on the similarity between human and porcine stomachs, for human studies. Thus, it can contribute in future to a reduction of animal experiments and can help to have a more comprehensive understanding of stomach functions. Prospective developments of the model could deal with the prediction of different functional impacts of tissue changes (i.e. chronic symptoms). Therefore, morphological and mechanical changes of the sickened tissue will be determined experimentally and implemented and converted into the model.
publications:
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- Papenkort, S., Borsdorf, M., Kiem, S., Böl, M., & Siebert, T. (2024). Regional differences in stomach stretch during organ filling and their implications on the mechanical stress response. 10.1016/j.jbiomech.2024.112107Journal of Biomechanics, 168 [Link]
- Papenkort, S., Borsdorf, M., Böl, M., Siebert, T., 2023. A geometry model of the porcine stomach featuring mucosa and muscle layer thicknesses. J Mech Behav Biomed Mater 142, 105801.[link]
- Klemm, L., Seydewitz, R., Siebert, T., Böl, M., 2023. Three-dimensional multi-field modelling of gastric arrhythmias and their effects on antral contractions. doi: 10.1016 Comput Biol Med 153, 106488.[link]
- Borsdorf, M., Böl, M., Siebert, T., 2021. Influence of layer separation on the determination of stomach smooth muscle properties. Pflugers Arch. Eur J Physiol 473, 911–920(2021).doi:10.1007/s00424-021-02568-5 [link]
- Bauer, M., Morales Orcajo, E., Klemm, L., Seydewitz, R., Fiebach, V., Siebert, T., Böl, M., 2020. Biomechanical and microstructural characterisation of the porcine stomach wall: Location- and layer-dependent investigations. Acta Biomater. [link]
- Klemm L., Seydewitz R., Borsdorf M., Siebert T., Böl M. (2020). On a coupled electro-chemomechanical model of gastric smooth muscle contraction, Acta Biomater,doi:10.1016/j.actbio.2020.04.007109, 163-181.[Link]
- Tomalka, A., Borsdorf, M., Bol, M., & Siebert, T. (2017). Porcine Stomach Smooth Muscle Force Depends on History-Effects. Front Physiol, 8, 802. doi:10.3389/fphys.2017.00802 [link]