Female XX sex chromosomes increase survival and extend lifespan in aging mice - PubMed (original) (raw)

Figure 2

XX sex chromosomes extended lifespan in combination with ovaries and independently increased survival during aging. (a–f) Kaplan–Meier curves of FCG aging cohort (n = 261 mice): XX(O) n = 64, XY(T) n = 48, XX(T) n = 94, and XY(O) n = 55. (a) In mice with ovaries, XX decreased mortality compared to XY (XX, HR = 0.46, CI = 0.23–0.94, *p = 0.03). (b) In mice with testes, mortality tended to be higher overall and did not differ between XX and XY genotypes (XX, HR = 0.81, CI = 0.43–1.50, p = 0.53). (c) In XX mice, ovaries decreased mortality compared to testes (ovaries, HR = 0.51, CI = 0.26–0.99, *p = 0.05). (d) In XY mice, mortality was lower overall and did not differ between those with testes or ovaries (ovaries, HR = 0.96, CI = 0.48–1.90, p = 0.90). (e, f) XX increased survival during aging in mice with ovaries and testes, as determined by a grid search method that statistically identifies the point in time that curves change in relation to each other (indicated by dotted vertical line); differences in lifespan before and after that time point are shaded (significant differences = green grid pattern; no difference = shaded red). (e) In mice with ovaries, the relationship between XX and XY lifespan curves changed at 21 months with no difference before then (XX, HR = 0.52, SE = 0.64, p = 0.31) and significant difference afterward (XX, HR = 0.37, SE = 0.45, *p = 0.01). (f) In mice with testes, the relationship between XX and XY lifespan curves changed at 23 months with a significant difference before then (XX, HR = 0.36, SE = 0.60, *p < 0.05) and no difference afterward (HR = −0.78, SE = 0.33, p = 0.23). HR = hazard ratio, CI = confidence interval, and SE = standard error; HR < 1 is decreased mortality risk (statistical details in Supporting Information Tables S3–S6)