Fenestration pattern in cultured LSEC analysed by scanning electron microscopy (SEM). The evolution of fenestrae in isolated LSECs seeded on fibronectin-coated coverslips was monitored at different time points by SEM. LSECs cultures were maintained at high (a-c) or low (d-f) oxygen levels. Highly fenestrated cells can be observed during early time points of culture. Fenestration is gradually lost over time in both normoxic or hypoxic conditions.