Fig. 8: CR promotes beta-cell longevity by slowing down beta-cell turnover rates.

A Study design. After 2 months of age, ¹⁵N-labeled mice were kept on AL, 20% CR or HFD for 12 months. B Multi-isotope imaging mass spectroscopy (MIMS) representation technique. C Validation of ¹⁵N incorporation by MIMS imaging and quantification of ¹⁵N/¹⁴N ratio in cortical neurons from a ¹⁵N-labeled mouse after chase with ¹⁴N diet for 12 months. Each dot represents a single neuronal nucleus (n = 21 nucleus from 2 cortical layers of 1 mouse) D MIMS of pancreatic islets from AL, CR, or HFD mice (n = 3 islets per animal, n = 1 mouse per diet group). E Single cell analysis of ¹⁵N/¹⁴N ratios in beta cells at day 0 (no chase) and after 12 months (mo) on AL, HFD, or CR diet. Each dot represents a single beta cell nucleus, pooled from 3 different islets of 1 mouse per diet group. Total of n = 54 AL 0mo, n = 217 AL 12mo, n = 114 HFD 12m0, and n = 194 CR 12mo beta cells were analyzed. The dotted horizontal pink and black lines represent the mean and the lowest ¹⁵N/¹⁴N levels found in cortical neurons shown in (C). F Estimation of beta cells that are estimated to be LLC or young after 12 months on AL, CR, or HFD. B, D scale bar = 10 microns. The p values for all significantly different comparison are shown. Statistical analysis was conducted using one-way ANOVA with Benjamini, Krieger, and Yekutieli’s post-hoc test (B). All data presented as mean ± 95% confidence intervals (C.l.). A was created with BioRender.com. and released under a Creative Commons Attribution-Non-Commercial NoDerivs 4.0 International license.