Fig. 5: Ca²⁺ dynamics of Ins1Cre:GCaMPffl/fl islets in Sham and VSG-treated animals following Exendin9 treatment.

a Body weight monitoring following VSG (red, n = 10 until week 4, then 6 animals) or sham surgery (black, n = 5 animals). P = 0.027 at week 10. b Time course of changes in Ca²⁺ activity from week 0 to week 8 (p = 0.001) and then following Exendin9 treatment on week 12 in sham (n = 3 animals, n = 11 islets) and VSG (n = 7 animals, n = 14 islets in weeks 4, 8 and 11 islets in weeks 0 and 12). Categories: 0. No activity, 1. Oscillations, 2. Partial Wave, 3. Wave, 4. Super Wave. c Baseline (week 0) categorisation of Ins1Cre:GCaMPf^fl/fl islets in sham and VSG mice on weeks 4 and 8 and following Exendin9 treatment on week 12 (sham: n = 3 animals, n = 11 islets; VSG n = 7 animals, n = 12 islets at weeks 4 and 8 and n = 10 at week 12). d Cartesian functional connectivity maps displaying the correlation coefficients of β-cells within the x–y position of analysed cells (dots). (i, ii) Example of islet implanted in sham animal at week 8 and week 12 post-Exendin9, (iii, iv) example of islet implanted in VSG-treated animal at week 8 and week 12 post-Exendin9. Cells are connected with a line where the strength of each cell pair connection (R) is colour coded: red for R of 0.76–1.0, yellow for R of 0.51–0.75, green for R of 0.26–0.5 and blue for R of 0.1–0.25. Red dots represent β-cells with the highest number of connected cell pairs. Ca²⁺ activity detected during the 30 s (100 frames) imaging period analysed is displayed at the top right of each connectivity map. e Baseline (week 0) corrected percentage of significantly connected cell pairs in sham (n = 3 mice, 8 islets) and VSG (n = 7 mice, 12 islets at week 4, then 9 islets at weeks 8 and 12), respectively. f Representative heatmaps depicting connectivity strength of all β-cell pairs (x–y axis). (i, ii) Example of islet implanted in sham animal at week 8 and week 12 post-Exendin9. (iii, iv) Example of an islet implanted in VSG-treated animal at week (8) and week 12 post-Exendin9. R values are colour coded from 0 to 1, blue to red, respectively. Red represents β-cell pairs with high connectivity strength. g Baseline (week 0)-corrected correlation coefficient (R) in sham (n = 3 animals, n = 8 islets) and VSG (n = 7 animals, n = 12 islets at week 4, n = 10 islets at week 8 and n = 7 islets at week 12), respectively. Data are means ± SEM and *p < 0.05, ***p < 0.001 by two-sided Student’s t-test. Data are expressed as means ± SEM. VSG vertical sleeve gastrectomy. Source data are provided as a Source Data file.