Reduced number of lipofuscin particles in T2D. (A) Visualization of autofluorescent lipofuscin particles in adipocytes from a nondiabetic subject (left), after treatment with 5 mmol/L CuSO4, 50 min (middle), and from a diabetic subject (right), using confocal fluorescence microscopy. Cell nuclei were stained with TO-PRO3 (blue). (B) Quantification of lipofuscin particles in adipocytes from 10 nondiabetic subjects (age 34–80, average 60.7 years; BMI 21–35, average 24.9 kg/m2). Cells were incubated without additions (control, open bar), with 50 nmol/L rapamycin (filled bar) or with 50 nmol/L rapamycin and 5 µmol/L chloroquine (hatched bar) for 18 h and then the number of lipofuscin particles was determined by fluorescence microscopy. Microscopic image of one cell after the respective treatment is shown above the corresponding graph bar. In each condition 20 cells were analyzed per subject. Results are given as number of lipofuscin particles per cell as a percentage of that in controls, for each subject, mean ± SE. (C) Quantification of lipofuscin particles in adipocytes from 17 nondiabetic subjects (open bar; age 34–80, average 56.7 years; BMI 21–38.3, average 26.9 kg/m2) and 10 diabetic patients (filled bar; age 46–76, average 60.9 years; BMI 27–66.7, average 39.7 kg/m2); 20 cells were analyzed per patient. Results are given as number of lipofuscin particles per cell, mean ± SE.