# Altered Mechano-Electrochemical Behavior of Articular Cartilage in Populations with Obesity
## 4 Conclusions  
In this work, a previously presented three-dimensional mechano-electrochemical model [19; 20] has been extended and employed to analyze and quantify the effect of obesity on cartilage behavior. This model can be considered the first 3D computational model for use in the study of the effects of obesity on articular cartilage. This study shows, for the first time, the relation between obesity and cartilage degeneration. It presents the first step when performing a more accurate and sophisticated model to provide patterns that indicate clinician when obesity is starting to affect tissues of the joints. This will let them prevent and treat, at a very early stage, tissue degradation.  
The model incorporates important biological and physical aspects of articular cartilage such as proteoglycan repulsion due to attached negative charges, diffusive-convective phenomena and the combined mechano-electrochemical events that occur in healthy as well as pathological tissue. Despite the promising use of the model, it does have some several limitations. First, anisotropic properties should be included in the model in order to analyze the influence of heterogeneity in tissue behavior under loading. Second, in the case of obesity, there is a lack of experimental parameters in the literature. Thus, for future advances, accurate experiments to measure specific cartilage properties are required.  
Several interesting insights into cartilage behavior in people with obesity have been evidenced. The results demonstrate that water and ion fluxes within the considered samples present significant alterations, showing a general increase in their values. The simulations also show how the cation concentration is reduced within the sample. Interestingly, these results closely resemble those previously obtained for the early stages of osteoarthritis.  
In light of these simulations, it is suggested that people with obesity, i.e., with a BMI greater than 30 kg/m\({}^{2}\), should undergo preventive osteoarthritis treatments to avoid homeostatic cartilage alteration and subsequent tissue deterioration. Besides, as expected, the deformation of the cartilage sample from obese patients is higher than that obtained from people of normal weight. These findings support the hypothesis of [PERSON] et al. [11] that there is a strong correlation between obesity and an increase in the risk of suffering osteoarthritis.  
The present model can be considered as a pioneer 3D computational model for simulating cartilage behavior in people with obesity. It could be a valuable tool for analyzing the effects of several cartilage pathologies taking into consideration mechano-electrochemical tissue behavior. Due to the complexity of in vivo experimental measurements of cartilage behavior in specific loading conditions, such as obesity, this model is presented as a predictive instrument to study the subsequent physiological and pathological processes. This, together with the capacity of the model to display the results in clinically interpretable three-dimensional images, make it an interesting novel tool for the diagnosis, monitoring and efficacy evaluation of potential cartilage therapies.  
The authors gratefully acknowledge financial support from the Spanish Ministry of Economy and Competitiveness (MINECO MAT2013-46467-C4-3-R and FPU graduate research program AP2010/2557), the Government of Aragon (DGA) and the Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN). CIBER-BBN is financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund.  
The conception and design of the study, or acquisition of data, or analysis and interpretation of data: [PERSON] and [PERSON]. Drafting the article or revising it critically for important intellectual content: [PERSON], [PERSON] and [PERSON]. Final approval of the version to be submitted: [PERSON], [PERSON] and [PERSON].  
The authors declare no conflict of interest.