TNF and ischemia: While some cardioprotective secreted proteins, such as follistatin-like 1 (Fstl1) and tumor necrosis factor (TNF)-α, can still be secreted during ischemic stress, secretion of other cardiokines, for example, encephalin and calcitonin gene-related peptide, is even enhanced by mild ischemia, which contributes to preserving cardiac function [3].