CDKN1A and Hyperglycemia: However, we did not observe any Cdkn1a or Mmp2 expression in Gcg+ islet cells in non-infiltrated/intact islets of 8-week mice, insulitic islets in 13-19-week old euglycemic NOD mice, or in residual islets of recently diabetic (<1 week after hyperglycemia) 19-20 week NOD mice (n = 3 mice per group) (Figure 2D).