Figure 1.

Diabetes mellitus is associated with increased mitochondrial fission in endothelial cells. Venous endothelial cells were collected from healthy volunteers (n=9) and patients with diabetes mellitus (n=10) as described in Methods. A: Mitochondria were labeled in live endothelial cells with Mitotracker Green FM (Invitrogen) and images were captured at 100X. A representative endothelial cell from a healthy control (left) shows a complex network of threadlike mitochondria, while a representative cell from a diabetic patient (right) shows smaller, punctate mitochondria. Fixed cells were stained for cytochrome c and mitochondrial network extent was rated in a blinded manner using a semi-quantitative scale. Network extent was lower in the diabetics (*P=0.002). B: Freshly isolated human venous endothelial cells were fixed and stained for Fis1 protein expression. A representative cell from a diabetic patient (right) shows markedly higher Fis1 expression compared to a cell from a healthy control (left). Pooled data show that Fis1 levels were significantly higher in the diabetics (n=6 per group, *P<0.0001).