Figure 9.

In vivo sickling scenarios.(Henry et al., 2020a) Schematic of microcirculation shows an arteriole, a capillary and venule. (A) The delay time is so long that cells do not sickle in the microcirculation and may even return to the lungs without sickling. (B) Sickling only occurs after the cell escapes the microcirculation and is unsickled upon oxygenation in the lungs. (C) The delay time is so short that polymerization occurs in the capillary to block further passage of cells, called a “log jam.” The surrounding tissues are adversely affected by decreased oxygen delivery. (D) Cells escape both the capillary and blockage by adherent sickled cells in the post-capillary venule. (E) Cells sickle and adhere to the endothelium of the post-capillary venule to cause a log jam. (F) Cell sickles in capillary but nevertheless escapes the microcirculation to the larger vessels. (G) Because the concentration of intracellular hemoglobin is so high that fibers are not completely melted in the lungs, the delay time is eliminated.(Mozzarelli et al., 1987) In this case, cells sickle before entering the microcirculation and may initiate a log jam in the arteriole.