Bone Remodeling Process and Covid-19: A Modelling Approach

Apart from the effects on the lungs, COVID-19 caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) also has effects on bone metabolism including the bone remodelling process. The bone remodelling process involves bone formation by bone-forming cells (osteoblasts) and bone resorption by bone-resorbing cells (osteoclasts). The infection with SARS-Cov-2 decreases the inhibiting effects of Angiotensin-converting enzyme 2 (ACE2) on osteoclastic reproduction and inhibits the osteogenic ability of osteoblasts which might lead to the imbalance in the bone remodeling process. In this study, we modify the system of differential equations to investigate the effects of Covid-19 on bone formation and bone resorption. The geometric singular perturbation method is utilized to analyze the modified model theoretically. To illustrate the theoretical results, numerical investigations are also demonstrated. The results indicate that the oscillations in the numbers of osteoclastic cells and osteoblastic cells observed in the clinical evidence could still be expected when the effects of SARS-Cov-2 are incorporated, however, the oscillations occur at the higher level of the number of osteoclasts and hence more bone loss might occur when infected with Covid-19.