Fig. 8
Numerical simulations of epithelial cells, densities of immune cells and concentrations of cytokines with age. The predicted volume fractions of (a) healthy and (b) damaged epithelial cells, densities of (c) macrophages, (d) regulatory T-cells, (e) T-cells and (f) plasma B-cells and concentrations of (g) anti- and (h) pro-inflammatory cytokines with age, from solving Eqs. (3)–(23) with baseline parameters given in Tables 1, 2 and 3 and age functions given in Figs. 2, 3, 4 and 5. The production rates \(D^{0}\) and \(D^{1}\) to attain a concentration of 50 nmol/L (red line) and 75 nmol/L (blue line) 25(OH)D at age 20 years are \(D^{0}=3.2\), 4.8 and \(D^{1}=0.35\), 0.5 nmol/L day−1, respectively.
