Analyzing and modeling rheological behavior of liver fibrosis in rats using shear viscoelastic moduli

Abstract

Abstract:The process of liver fibrosis changes the rheological properties of liver tissue. This study characterizes and compares liver fibrosis stages from F0 to F4 in rats in terms of shear viscoelastic moduli. Here two viscoelastic models, the Zener model and Voigt model, were applied to experimental data of rheometer tests and then values of elasticity and viscosity were estimated for each fibrosis stage. The results demonstrate that moderate fibrosis (≤F2) has a good correlation with liver viscoelasticity. The mean Zener elasticity E 1 increases from (0.452±0.094) kPa (F0) to (1.311±0.717) kPa (F2), while the mean Voigt elasticity E increases from (0.618±0.089) kPa (F0) to (1.701±0.844) kPa (F2). The mean Zener viscosity increases from (3.499±0.186) Pa·s (F0) to (4.947±1.811) Pa·s (F2) and the mean Voigt viscosity increases from (3.379±0.316) Pa·s (F0) to (4.625±1.296) Pa·s (F2). Compared with viscosity, the elasticity shows smaller variations at stages F1 and F2 no matter what viscoelastic model is used. Therefore, the estimated elasticity is more effective than viscosity for differentiating the fibrosis stages from F0 to F2.

Association between serum vitamin D and severity of liver fibrosis in chronic hepatitis C patients: a systematic meta-analysis

“…Chronic hepatitis C is considered to be a major cause of liver disease, including progressive liver fibrosis, cirrhosis, and hepatocellular carcinoma (Hoofnagle, 2002;Shepard et al, 2005;Thomas and Seeff, 2005;Micallef et al, 2006;Zhu et al, 2014). The risk factors like older age, consumption of alcohol, metabolic alterations, liver necroinflammation, duration of infection and viral co-infections (Poynard et al, 2003), and insulin resistance (Romero-Gómez et al, 2005) can influence the degree of liver fibrosis.…”

Measurement of Liver Stiffness Using Shear Wave Elastography in a Rat Model: Factors Impacting Stiffness Measurement with Multiple- and Single-Tracking-Location Techniques

“…However, this was not applied in this work because the model is intended for shear waves and not Scholte waves. Other models such as linear fit in Nightingale et al (2015) and Zener in Zhu et al (2014b) also make assumptions about planar shear wave geometries. Even if the beam spacing dependence can be eliminated using such a model, it may be simply fitting geometric unknowns with parameters assumed to be material.…”

Mathematical modeling of bioactive arterial wall

“…The model is a modified viscoelastic Zener model with one active element. Passive Zener model is widely used for interpretation of the experimental data obtained on single cells by atomic force microscopy or optical tweezers [14,15]. The rheological equation for the model is [13] :…”

“…The corresponding relaxation curves for the five element model can be also written in the forms (9) and (12) accordingly. Despite the tree element model, the five element one exhibits the two time relaxation processes for both stress and strain relaxations that is more common for the biological tissues especially in the pathological state [14,15,16].…”