Panel A shows a line graph for males, with the x-axis labeled Sarcomere Length [micrometers] ranging from 1.8 to 2.2 and the y-axis labeled XB stress [millinewtons per square millimeter] ranging from 0.0 to 2.5. Two lines are plotted: one for male control (open circles, dashed line) and one for male HFpEF (filled circles, solid line). The male HFpEF line shows a significant increase in XB stress with increasing sarcomere length, indicated by asterisks for statistical significance. Panel B shows a similar line graph for females, with the x-axis labeled Sarcomere Length (micrometers) ranging from 1.8 to 2.2 and the y-axis labeled XB stress [millinewtons per square millimeter] ranging from 0.0 to 2.5. Two lines are plotted: one for female control (open diamonds, dashed line) and one for female HFpEF (filled diamonds, solid line). The female HFpEF line does not show a significant increase in XB stress with increasing sarcomere length. Panel C shows a line graph for males, with the x-axis labeled Sarcomere Length [micrometers] ranging from 1.9 to 2.2 and the y-axis labeled XB stress/Total Stress ranging from 0.0 to 1.0. Two lines are plotted: one for male control (open circles, dashed line) and one for male HFpEF (filled circles, solid line). The male HFpEF line shows a decrease in the ratio of XB stress to total stress with increasing sarcomere length. Panel D shows a similar line graph for females, with the x-axis labeled Sarcomere Length (micrometers) ranging from 1.9 to 2.2 and the y-axis labeled XB stress/Total Stress ranging from 0.0 to 1.0. Two lines are plotted: one for female control (open diamonds, dashed line) and one for female HFpEF (filled diamonds, solid line). The female HFpEF line shows a significant decrease in the ratio of XB stress to total stress with increasing sarcomere length, indicated by asterisks for statistical significance.
The extent of diastolic XBs is increased in male HFpEF-like but not in female HFpEF-like cardiomyocytes. (A and B) XB stress across diastolic SLs in cardiomyocytes from control vs. HFpEF-like males (A) and females (B). (C and D) The ratio of diastolic XBs to total diastolic stress across diastolic SLs of control vs. HFpEF-like cardiomyocytes of male (C) and female (D) mice. The data are presented as means ± SE. The sample sizes are 11, 13, 10, and 12 mice for male-ctrl, male HFpEF-like, female-ctrl, and female HFpEF-like, with 2–4 cells analyzed per mouse. Analysis was performed using a linear mixed model at individual SLs. Simple linear regression was used to compare the slopes of the XB–SL relations (A and B). *P ≤ 0.05, **P ≤ 0.01, and ***P ≤ 0.001.