Skip to main content
2023 BMES Annual Meeting Main banner
Icon Legend
This session is not in your schedule.
This session is in your schedule. Click again to remove it.
Back

    Women's Health

    (M-493) Characterizing the association between the gene expression of major collagens and estradiol throughout the menstrual cycle.

    Thursday, October 12, 2023
    9:30 AM – 10:30 AM PDT
    Location: Exhibit Hall - Row M - Poster # 493
    Introduction::
    The extracellular matrix (ECM) of skeletal muscle is crucial for maintaining the mechanical properties and regenerative capacity of the tissue. Collagens, major components of the ECM, form the intramuscular connective tissue (IMCT), consisting of the epimysium, perimysium, and endomysium layers. Collagens 1 and 3 make up 75% of the total muscle collagen and bring rigidity and elasticity to the ECM, respectively. Collagens 4 and 6 are found in the basement membrane (endomysium) where they play critical roles in promoting muscle regeneration. Research has shown that collagen synthesis in skeletal muscle is influenced by estradiol, but previous studies have mainly focused on total collagen levels resulting in limited information on the effects of estrogen on collagens 1,3, 4, and 6. Investigating this relationship is important for understanding how estrogen fluctuations may impact muscle injury healing and recovery in women with altered estradiol levels (e.g. amenorrhea, menopause), as well as exploring potential therapeutic strategies for enhancing muscle repair.


    Materials and Methods:: This study was conducted per the UT Southwestern (SW) Human Research Protection Program. Pre-menopausal women (n=19) between the ages of 18-39 undergoing hip surgery at UTSW Medical Center were recruited. Whole blood and a biopsy from the gluteus medius were collected from each subject and analyzed for endogenous hormone levels and protein/gene expression, respectively. The blood was sent to a clinical laboratory service for hormone analysis. Muscle biopsies were partitioned and frozen in liquid nitrogen for future histological/protein analyses. To determine gene expression via quantitative polymerase chain reaction (qPCR), a partition of frozen muscle tissue was pulverized. Total RNA was extracted using Trizol and was reverse transcribed using standard procedures (High-capacity cDNA reverse transcription kit, applied biosystems). The collagen genes of interest Collagen (col) 1a, col-3a, col-4a, and col-6a were amplified from cDNA using Taqman Universal PCR Master Mix and detected using Taqman primers. Data were normalized to 18s (housekeeping gene). Gene expression was reported as a relative quantity (RQ) calculated by the following equation RQ= 2^(-∆C_T ), where CTGene Interest – CT Housekeeping Gene. Estradiol concentrations are reported in pg/ml. For this study we only included female subjects that were in menses or follicular phase (n=12), to ensure progesterone concentrations were negligible in order to characterize estradiol effects only.  A simple linear regression was performed to assess the relationship between collagen expression and estradiol concentration where α = 0.05.

    Results, Conclusions, and Discussions::

    Results
    The range of estradiol concentrations for the subjects was 26-356 pg/mL. The range of progesterone concentrations for subjects was 0.5-1 ng/mL. Following linear regression analysis, collagen 1,3, and 6 relative gene expression and estradiol concentration had no significant relationship (p = 0.5339, 0.6613, and 0.3167 respectively). However, collagen 4 RQ showed a statistically significant, positive relationship with estradiol concentration (p = 0.0358).

    Conclusions

    The purpose of this study was to determine if collagen gene expression in skeletal muscle biopsies is associated with circulating estradiol levels in eumenorrheic women. The results from our study suggest a significant relationship between collagen 4 gene expression and circulating estradiol concentration. While the mechanism in which collagen 4 promotes muscle regeneration is still not fully known it has been hypothesized that collagen 4 promotes the IGF1-mediated migration, differentiation, and fusion of myoblasts, thus promoting the regeneration of skeletal muscle (Ito et al. 2015). This may provide an estradiol-driven mechanism explaining why women with low estradiol levels (e.g., amenorrheic, post-menopausal) have poor muscle regeneration after injury, and potentially suggesting a therapeutic target (Col 4 production) to improve muscle regeneration. Future directions for this study include increasing the sample size and determining if these transcriptional changes manifest in an increase in col 4 protein.



    Acknowledgements (Optional): :

    References (Optional): :

    • Ito, Akira, et al. “Effects of Type IV Collagen on Myogenic Characteristics of IGF-I Gene-Engineered Myoblasts.” Journal of Bioscience and Bioengineering, vol. 119, no. 5, 15 Oct. 2014, pp. 596–603, https://doi.org/10.1016/j.jbiosc.2014.10.008.

    • Chidi-Ogbolu, N., & Baar, K. (2019). Effect of Estrogen on Musculoskeletal Performance and Injury Risk. Frontiers in physiology, 9, 1834. https://doi.org/10.3389/fphys.2018.01834

    • Csapo, Robert, et al. “Skeletal Muscle Extracellular Matrix – What Do We Know about Its Composition, Regulation, and Physiological Roles? A Narrative Review.” Frontiers in Physiology, vol. 11, 2020, https://doi.org/10.3389/fphys.2020.00253.