Panel A and B are line graphs showing passive stress in male and female mice, respectively. Panel C consists of four scatter plots showing the correlation between diastolic XB stress and passive sarcomere stress. Panel A shows passive stress measured in male mice. The x-axis represents sarcomere length in micrometers ranging from 1.8 to 2.2, and the y-axis represents passive stress in megapascals per square millimeter ranging from 0 to 8. Two data series are plotted: male-ctrl (black dashed line with open circles) and male HFpEF-like (red dashed line with filled circles). The male HFpEF-like group shows higher passive stress across all sarcomere lengths compared to the male-ctrl group, with significant differences indicated by asterisks. Panel B shows passive stress measured in female mice. The x-axis represents sarcomere length in micrometers ranging from 1.8 to 2.2, and the y-axis represents passive stress in megapascals per square millimeter ranging from 0 to 8. Two data series are plotted: female-ctrl (black dashed line with open diamonds) and female HFpEF-like (red dashed line with filled diamonds). The female HFpEF-like group shows higher passive stress across all sarcomere lengths compared to the female-ctrl group, with significant differences indicated by asterisks. Panel C consists of four scatter plots showing the correlation between diastolic XB stress and passive sarcomere stress at a sarcomere length of 2.1 micrometers for four experimental groups: male-ctrl, male HFpEF-like, female-ctrl, and female HFpEF-like. The x-axis represents passive sarcomere stress in megapascals per square millimeter ranging from 0 to 4, and the y-axis represents XB stress in megapascals per square millimeter ranging from 0 to 4. Each scatter plot includes a trend line indicating the correlation. The data points represent individual cells, and there is no clear correlation between sarcomere passive stress and the extent of diastolic XB stress.
Passive sarcomere stress is increased in cardiomyocytes from both male HFpEF-like and female HFpEF-like mice. (A and B) Diastolic stress measured in cardiomyocytes following combined treatment with BDM and colchicine, which inhibit XB activity and depolymerize microtubules, reflects passive sarcomere stress. (A and B) Passive sarcomere stress is elevated in cardiomyocytes from male HFpEF-like (A) and female HFpEF-like mice (B) compared with their respective controls. (C) The correlation between diastolic XB stress and passive sarcomere stress at a SL of 2.1 µm is plotted for four experimental groups: male-ctrl, male HFpEF-like, female-ctrl, and female HFpEF-like (C). There is no correlation between sarcomere passive stress and the extent of diastolic XB stress. For A and B, the data are presented as means ± SE. The sample sizes are 9, 10, 8, and 11 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, *P ≤ 0.05. For C, the sample sizes include n = 19, 32, 23, and 29 cells from 9, 10, 8, and 11 mice for male-ctrl, male HFpEF-like, female-ctrl, and female HFpEF-like, respectively. Analysis was performed using Pearson correlation. Each data point represents an individual cell.