H2AX and hydrops fetalis: Furthermore, expression of the senescence markers, including p53, p16, PAI‐1, γ‐H2AX, and IL‐6 in the HF bulge region of the IGF‐1/SIRT1 DTg mice was comparable to that in age‐matched WT or SIRT1 Tg mice, but significantly lower than that observed in IGF‐1 Tg mice (Figure 3c).