In vitro sex specific cardiac structure-contractility of neonatal rat cardiac sheets
Data files
Jun 16, 2026 version files 93.75 KB
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README.md
6.91 KB
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SingleCell_Structure.xlsx
12.73 KB
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Stress_Output.xlsx
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Tissue_Structure.xlsx
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Abstract
Even though in vivo rodent studies have been instrumental in investigating sex-specific differences in cardiac health, function, and pathology, they fall short in providing a fast and flexible platform for investigating sex differences of cardiac tissue in isolation. In vitro platforms offer an accessible and more controlled alternative to dissect and study the mechanisms by which male and female cardiac tissues differ from one another. Here, we have shown on an in vitro heart-on-a-chip platform, primary neonatal rat ventricular myocytes can serve as a viable model showing sex-driven characteristics even in the absence of supplemented hormones. With controlled experimental conditions, the self-assembly of isolated cardiomyocytes resulted in morphological differences in the structure of the contractile apparatus. More importantly, the assembly of cardiac cells into tissues had a sex-driven divergence in both tissue structure and the corresponding function. This work is the first characterization of the difference between sex-specific NRVMs in in vitro culture. Thus, this offers an avenue to investigate sex-based variations in cardiac function that are otherwise difficult to study.
Dataset DOI: 10.5061/dryad.rjdfn2zp2
Description of the data and file structure
This dataset contains raw values of sarcomeric structure quantification and stress production of sex-specific, aligned cardiac sheets generated from neonatal rat ventricular myocytes on an in vitro heart-on-a-chip platform. The work is currently published on the Proceedings of the National Academy of Sciences (PNAS) (doi: 10.1073/pnas.2519130123).
Files and variables
File: Stress_Output.xlsx
Description: Reports measured values of stress generated from muscular thin film samples (systolic, diastolic, and active stress) in kPa, and their calculated stresses at the sarcomere level, labeled for each sex and their corresponding seeding density.
- Cell_Type: Neonatal rat ventricular myocytes (NRVM) labeled for Female (_F) or Male (_M).
- NRVM_Count: Seeding density.
- Low: 3.7 x 105 cells per cm2.
- Mid: 4.3 x 105 cells per cm2.
- High: 5.2 x 105 cells per cm2.
- Sys_Stress_kPa: Systolic stress generated in kPa.
- Dias_Stress_kPa: Diastolic stress generated in kPa.
- Active_Stress_kPa: Active stress generated in kPa.
- Seed_Date: the date in which the cells were seeded on the heart-on-a-chip substrate (YYYYMMDD).
- ActinCM per pixel image (%): the cell area calculated as percentage of the total image area. Calculated from the accompanying Tissue_Structure data and used in the following metrics:
- Sys Stress per ActinCM% (Pa/%): Avarege systolic stress per cell area
- Dias Stress per ActinCM% (Pa/%): Average diastolic stress per cell area
- Active Stress per ActinCM% (Pa/%): Avarage active stress per cell area
- Cross sectional area of a myofibril/sarcomere/think filaments (nm^2): the cross-sectional area of a sarcomere. Used in the following metrics:
- Sys Force (pN): Average systolic force generated by a single sarcomere in pN.
- Dias Force (pN): Average diastolic force generated by a single sarcomere in pN.
- Active force (pN): Average active force generated by a single sarcomere in pN.
- Average nuclei count: the average number of nuclei counted from fluorescent images. Calculated from the accompanying Tissue_Structure data. Used in the following metrics:
- Sys Stress per Nuclei (kPa): Average systolic stress generated per nuclei in kPa.
- Dias Stress per Nuclei (kPa): Average diastolicstress generated per nuclei in kPa.
- Active Stress per Nuclei (kPa): Average active stress generated per nuclei in kPa.
File: SingleCell_Structure.xlsx
Description: Reports structural metrics for single cardiomyocytes, labeled for each sex. Each row is one cardiomyocyte.
- OOPzline: the orientational order paramter of the cell's z-lines. Ranges from 0 (disorganized) to 1 (high organized and aligned).
- OOPactin: the orientational order paramter of the cell's actin/cytoskeleton. Ranges from 0 (disorganized) to 1 (high organized and aligned).
- ZlineFraction: the fraction of α-actinin signals that were classified as z-lines over the total α-actinin signals. Measures the tissue's maturity. Ranges from 0 (no z-lines formed) to 1 (all α-actinin formed z-liens).
- MedianCZL (µm): median length of continuous z-lines calculated in µm.
- MeanCZL (µm): mean length of continuous z-lines calculated in µm.
- TotalCZL (µm): total lengths of continuous z-lines calculated as the sum of all continuous z-line lengths in µm.
- Longer continuous z-lines represents better maturity in isolated cells.
File: Tissue_Structure.xlsx
Description: Reports structural metrics for aligned, cardiac sheets, labeled for each sex. Each row is one sample, which constitutes one chip.
- SeedDate: the date in which the cells were seeded on the heart-on-a-chip substrate (YYYYMMDD).
- NRVM_Count: Seeding density.
- Low: 3.7 x 105 cells per cm2.
- Mid: 4.3 x 105 cells per cm2.
- High: 5.2 x 105 cells per cm2.
- NumberofImages: total number of fluorescent images taken for a single chip.
- CardiomyocyteOOP: the orientational order parameter for cardiomyocyte-specific actin. Ranges from 0 (disorganized) to 1 (high organized and aligned).
- FibroblastOOP: the orientational order parameter for fibroblast-specific actin. Ranges from 0 (disorganized) to 1 (high organized and aligned).
- NumCardiomyocyteOrientVectors: the number actin pixels that were classified as cardiomyocytes. Written as the sum of the classified pixels of NumberofImages.
- NumFibroblastOrientVectors: the number of actin pixels that were classified as fibroblasts. Written as the sum of the classified pixels of NumberofImages.
- ActinCM per pixel image: cardiomyocyte cell area calculated as the percentage (%) of NumCardiomyocyteOrientVectors over total pixel area of NumberofImages.
- ActinFB per pixel image: fibroblast cell area calculated as the percentage (%) of NumFibroblastOrientVectors over total pixel area of NumberofImages.
- Cell_Type: Neonatal rat ventricular myocytes (NRVM) labeled for Female (_F) or Male (_M).
- Zline_Fraction: the fraction of α-actinin signals that were classified as z-lines over the total α-actinin signals. Measures the tissue's maturity. Ranges from 0 (no z-lines formed) to 1 (all α-actinin formed z-liens).
- Zline_OOP: the orientational order parameter of the cardiomyocyte z-lines. Ranges from 0 (disorganized) to 1 (high organized and aligned).
- Zline_Angle_Count: the number of z-line pixels written as the sum of z-line pixels of NumberofImages.
- Actin_Angle_Count: the number of total actine pixels written as the sum of z-line pixels of NumberofImages.
- ContL_Mean: mean length of continuous z-lines calculated in µm. Longer continuous z-lines represents better maturity and more confluous tissue.
- Zline_per_CMActin: z-line density within the cardiomyocyte-specific area. Calculated as the number of z-lines over ActinCM per pixel image.
- Zline_density_image: z-line density of the overal image area. Calculated as the number of z-lines over total image area of NumberofImages.
- Mean_Nuclei_Num: the counted average of nuclei per image.
- Zline_Angle_Count/Sum_Nuclei_Num: Z-line density calculated as the number of z-lines over the total nuclei number in percentage (%).
- NumCardiomyocyteOrientVectors/Sum_Nuclei_Num: average cardiomyocyte area of a nuclei in pixels.
- CellArea_per_nuclei: avereage cardiomyocyte area of a nuclei in µm2.
- Average_SarcLength (µm): average sarcomeric length in µm. The average distance between one z-line to the next.
- Tissue Thickness (µm): measured thickness of the cardiomyocyte tissue in µm. N/A: data was not recorded.