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Representative Sinusoids for Hepatic Four-Scale Pharmacokinetics Simulations.

Schwen LO, Schenk A, Kreutz C, Timmer J, Bartolomé Rodríguez MM, Kuepfer L, Preusser T - PLoS ONE (2015)

Bottom Line: This approach results in an integrated four-scale model, from single cells via sinusoids and the organ to the whole organism, capable of mechanistically representing metabolization inhomogeneity in livers at different spatial scales.Moreover, the model shows circulatory mixing effects due to a delayed recirculation through the surrounding organism.In particular, our results show that simultaneously considering variations at all relevant spatial scales may be necessary to understand their impact on observations at the organism scale.

View Article: PubMed Central - PubMed

Affiliation: Fraunhofer MEVIS, Bremen, Germany.

ABSTRACT
The mammalian liver plays a key role for metabolism and detoxification of xenobiotics in the body. The corresponding biochemical processes are typically subject to spatial variations at different length scales. Zonal enzyme expression along sinusoids leads to zonated metabolization already in the healthy state. Pathological states of the liver may involve liver cells affected in a zonated manner or heterogeneously across the whole organ. This spatial heterogeneity, however, cannot be described by most computational models which usually consider the liver as a homogeneous, well-stirred organ. The goal of this article is to present a methodology to extend whole-body pharmacokinetics models by a detailed liver model, combining different modeling approaches from the literature. This approach results in an integrated four-scale model, from single cells via sinusoids and the organ to the whole organism, capable of mechanistically representing metabolization inhomogeneity in livers at different spatial scales. Moreover, the model shows circulatory mixing effects due to a delayed recirculation through the surrounding organism. To show that this approach is generally applicable for different physiological processes, we show three applications as proofs of concept, covering a range of species, compounds, and diseased states: clearance of midazolam in steatotic human livers, clearance of caffeine in mouse livers regenerating from necrosis, and a parameter study on the impact of different cell entities on insulin uptake in mouse livers. The examples illustrate how variations only discernible at the local scale influence substance distribution in the plasma at the whole-body level. In particular, our results show that simultaneously considering variations at all relevant spatial scales may be necessary to understand their impact on observations at the organism scale.

No MeSH data available.


Related in: MedlinePlus

Model Overview.The figure shows the four spatial scales present in our multiscale pharmacokinetics simulation framework. The connection between the scales is given by the blood flow, indicated by arrows. The ‘representative sinusoids’ are the central building blocks in our framework. For each of these, we solve an advection-reaction problem. (HA: hepatic artery; HV: hepatic vein; PV: portal vein.)
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pone.0133653.g002: Model Overview.The figure shows the four spatial scales present in our multiscale pharmacokinetics simulation framework. The connection between the scales is given by the blood flow, indicated by arrows. The ‘representative sinusoids’ are the central building blocks in our framework. For each of these, we solve an advection-reaction problem. (HA: hepatic artery; HV: hepatic vein; PV: portal vein.)

Mentions: Our model consists of four separate building blocks, each representing a distinct physiological spatial scale as described above, see Fig 2. The connection from body via organ and sinusoids to the cells, and back, is provided via the blood flow. Bile flow and lymph flow, such as considered in [36], are not part of our model as the flowing volumes are negligible compared to the blood flow.


Representative Sinusoids for Hepatic Four-Scale Pharmacokinetics Simulations.

Schwen LO, Schenk A, Kreutz C, Timmer J, Bartolomé Rodríguez MM, Kuepfer L, Preusser T - PLoS ONE (2015)

Model Overview.The figure shows the four spatial scales present in our multiscale pharmacokinetics simulation framework. The connection between the scales is given by the blood flow, indicated by arrows. The ‘representative sinusoids’ are the central building blocks in our framework. For each of these, we solve an advection-reaction problem. (HA: hepatic artery; HV: hepatic vein; PV: portal vein.)
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4519332&req=5

pone.0133653.g002: Model Overview.The figure shows the four spatial scales present in our multiscale pharmacokinetics simulation framework. The connection between the scales is given by the blood flow, indicated by arrows. The ‘representative sinusoids’ are the central building blocks in our framework. For each of these, we solve an advection-reaction problem. (HA: hepatic artery; HV: hepatic vein; PV: portal vein.)
Mentions: Our model consists of four separate building blocks, each representing a distinct physiological spatial scale as described above, see Fig 2. The connection from body via organ and sinusoids to the cells, and back, is provided via the blood flow. Bile flow and lymph flow, such as considered in [36], are not part of our model as the flowing volumes are negligible compared to the blood flow.

Bottom Line: This approach results in an integrated four-scale model, from single cells via sinusoids and the organ to the whole organism, capable of mechanistically representing metabolization inhomogeneity in livers at different spatial scales.Moreover, the model shows circulatory mixing effects due to a delayed recirculation through the surrounding organism.In particular, our results show that simultaneously considering variations at all relevant spatial scales may be necessary to understand their impact on observations at the organism scale.

View Article: PubMed Central - PubMed

Affiliation: Fraunhofer MEVIS, Bremen, Germany.

ABSTRACT
The mammalian liver plays a key role for metabolism and detoxification of xenobiotics in the body. The corresponding biochemical processes are typically subject to spatial variations at different length scales. Zonal enzyme expression along sinusoids leads to zonated metabolization already in the healthy state. Pathological states of the liver may involve liver cells affected in a zonated manner or heterogeneously across the whole organ. This spatial heterogeneity, however, cannot be described by most computational models which usually consider the liver as a homogeneous, well-stirred organ. The goal of this article is to present a methodology to extend whole-body pharmacokinetics models by a detailed liver model, combining different modeling approaches from the literature. This approach results in an integrated four-scale model, from single cells via sinusoids and the organ to the whole organism, capable of mechanistically representing metabolization inhomogeneity in livers at different spatial scales. Moreover, the model shows circulatory mixing effects due to a delayed recirculation through the surrounding organism. To show that this approach is generally applicable for different physiological processes, we show three applications as proofs of concept, covering a range of species, compounds, and diseased states: clearance of midazolam in steatotic human livers, clearance of caffeine in mouse livers regenerating from necrosis, and a parameter study on the impact of different cell entities on insulin uptake in mouse livers. The examples illustrate how variations only discernible at the local scale influence substance distribution in the plasma at the whole-body level. In particular, our results show that simultaneously considering variations at all relevant spatial scales may be necessary to understand their impact on observations at the organism scale.

No MeSH data available.


Related in: MedlinePlus