Fig. 8: Age-associated changes in bone remodelling and regeneration.

a, UMAP visualization of bone ECs from 75-week-old bone with colour-coded subclusters. b, Bar plot showing the proportion of cells from each EC subcluster in adult and aged bone. Percentage (%) differences are indicated for rECs and aECs. Data are representative of an individual sample (Methods) (a) and integrated scRNA-seq data from all age groups (b). c,d, High-magnification confocal images of TB (c) and compact bone (CB) (d) immunostained for EMCN (red), VEGFR3 (blue) RUNX2 (yellow arrowheads, marking osteoprogenitors) and ATP6V1B1B2 (green arrowheads, marking osteoclasts). e, High-magnification two-photon microscopy images of CB immunostained for EMCN (red) and VEGFR3 (blue) together with second-harmonic generation (white) showing the changes during ageing. f, Confocal tile-scan images showing EMCN⁺VEGFR3⁻ rECs in untreated 12-week-old and 75-week-old mice femur and in response to treatment with alendronate (ALN) or PTH, as indicated. Note expansion of EMCN⁺ VEGFR3⁻ vessels in CB in response to ageing or treatments (arrowheads). g, Representative confocal images showing EMCN⁺VEGFR3⁻ rECs and OSTERIX (green) immunostaining in 75-week-old control, ALN-treated or PTH-treated CB (white arrowheads, marking type R capillaries during ageing). White dashed lines in d–g indicate compact bone (CB) area. h,i, Quantitation of EMCN⁺CAV1⁺ vessel density across age groups (h), EMCN⁺VEGFR3⁻ vessel density in 75-week-old control, ALN-treated or PTH-treated groups, and number of OSTERIX⁺ cells in CB after ALN and PTH treatment compared with respective controls (i). n = 3 mice per group. Mean ± s.e.m. P values were obtained using ordinary ANOVA.

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