R7500

To increase AGE content, 3 bone samples from each donor (5 males, age range: 46 to 60 years, 54.8 ± 5.5 years, and 5 females, age range: 53 to 58 years, 55.4 ± 2.1 years; Supplemental Table S1) were incubated in 100 mM sodium phosphate buffer for 4 weeks without sugar or with 0.1 M or 0.5 M D‐ribose (R7500, Sigma‐Aldrich) at 37°C. An additional 3 bone samples from the same donors were incubated as described above but also had 50 mM pyridoxamine added. For glucose incubations, 3 bone samples from each donor (5 males, age range: 46 to 60 years, 54.8 ± 5.5 years, and 5 females, age range: 47 to 60 years, 54.2 ± 4.9 years; Supplemental Table S1) were incubated either without sugar or with 0.1 M or 0.5 M D‐glucose (G8270, Sigma‐Aldrich) as described above for a total period of 16 weeks with analysis at 4 weeks, 8 weeks, and 16 weeks. Sodium azide (final concentration of 0.02%) was added to all the buffered solutions to prevent bacterial growth. The pH range for all groups was maintained between 7.0 and 7.5 during incubation by addition of small amounts of 10 N NaOH. After incubation, all bone specimens were rinsed with PBS, placed in this buffer, and stored at −20°C until analyzed.

Cells of 3x10⁵/well 6 well plate or 2x10⁴/well 96 well plate were seeded in triplicate in the growth medium unless specified otherwise. The following day, the medium was supplemented with ribitol (A5502 Sigma, St. Louis) or D-ribose (R7500 Sigma) or xylitol (X3375 Sigma) at a concentration of 10 mM, unless otherwise noted, and the cells were grown in the supplement for 3 days. Plates were washed with PBS and cells were processed for analysis by FACS, metabolomics, immunocytochemistry, and western blot.