bioRxiv Science⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/2024.11.25.625290

Sex Differences in Middle Cerebral Artery Reactivity and Hemodynamics Independent from Changes in Systemic Arterial Stiffness in Adult Sprague-Dawley Rats

Yamaleyeva, L.·Pulgar, V. M.·Ray, J.·Sun, X.·Cruz-Diaz, N.
View original source ↗Export metadata ↓

Abstract

Young women are protected against cerebrovascular disease compared with men. However, the underlying mechanisms of sex differences in cerebrovascular function are not well understood. In this study, we determined whether sex differences in middle cerebral artery (MCA) reactivity are accompanied with changes in cerebral or systemic arterial resistance and stiffness in adult 25-week-old Sprague-Dawley (SD) rats. No differences in systolic or diastolic blood pressures were observed between sexes. Heart rate was higher in the female versus male SD. Left MCA pulsatility index (PI) was lower in female versus male SD, while no differences in left intracranial internal carotid artery (ICA) PI was observed between sexes. There were no differences in thoracic aorta or left common carotid artery pulse wave velocity (PWV) between sexes. In isolated MCA segments, female left MCA had lower contraction to potassium, but similar maximal contraction and sensitivity to thromboxane A2 receptor agonist U46619. Pre-incubation with indomethacin lowered maximal response and sensitivity to U46619 in male MCA but not female MCA suggesting that vasoconstrictor prostaglandins may have a greater role in male MCA vs. female MCA. Endothelial nitric oxide synthase (eNOS) and vascular smooth muscle layer thromboxane A2 receptor immunoreactivity were greater in female versus male SD. We conclude that sex differences in the MCA reactivity are associated with a differential functional profile of MCA in adult SD rats independent from changes in systemic PWV. NEW & NOTEWORTHYDespite the debilitating effects of cerebrovascular disease in women, the basis for sex differences in cerebrovascular dysfunction remains incompletely understood. Our study demonstrated that middle cerebral artery reactivity and hemodynamics are not accompanied by changes in central pulse wave velocity in mature adult Sprague-Dawley rats suggesting different mechanisms underlying baseline vascular reactivity of cerebral versus systemic arterial beds.

Source connections

Explore related subjects

physiologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Yamaleyeva, L., Pulgar, V. M., Ray, J., Sun, X., Cruz-Diaz, N.. 2024-11-28. Sex Differences in Middle Cerebral Artery Reactivity and Hemodynamics Independent from Changes in Systemic Arterial Stiffness in Adult Sprague-Dawley Rats. https://doi.org/10.1101/2024.11.25.625290

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

IBD-Derived Colonic Fibroblasts Exhibit an Osteopontin-Enriched Secretome, and Osteopontin Restrains Human Colonic Organoid Maturation

Background: Intestinal fibroblasts are extensively remodeled in inflammatory bowel disease (IBD), yet the soluble stromal signals that directly influence epithelial maturation remain incompletely understood. We examined whether fibroblasts derived from inflamed IBD colon display an osteopontin (OPN; SPP1)-enriched secretory phenotype and whether extracellular OPN directly modifies non-neoplastic human colonic epithelium. Methods: Conditioned media from 5 noninflamed-associated fibroblast (NAF) and 4 inflammatory-associated fibroblast (IAF) cultures were analyzed in the validated multi-donor cytokine-array matrix, with orthogonal SPP1 RT-qPCR validation in a complementary fibroblast cohort. Recombinant OPN was then tested in human colonic organoids from 3 donors using donor-resolved molecular and functional analyses under standard, fibroblast-conditioned, and WNT-modified culture conditions. Donor identity defined biological replication. Results: OPN showed the strongest positive rank-based separation between IAF and NAF cultures: all 4 IAF values were higher than all 5 NAF values (Cliff's delta=1.00; exact Mann-Whitney P=0.0159; median ratio=3.64; Benjamini-Hochberg q=.19). Fibroblast RT-qPCR showed approximately 10-fold higher mean SPP1 expression in IAF than NAF cultures (P<.05). In organoids, OPN consistently reduced KRT20, FABP1, CA2, and MUC2 from Day 5 to Day 9. SOX9, HES1, and NOTCH1 increased at Day 9, whereas LGR5 and ALDH provided no evidence of canonical stem-cell expansion. Organoid-area and EdU responses were modest and donor dependent. Conclusions: IBD-derived colonic fibroblasts can display an OPN-enriched secretory phenotype. In human colonic organoids, OPN is sufficient to impair epithelial maturation, whereas its effects on growth and proliferation are variable and depend on the surrounding niche.

physiology↗
bioRxiv2026

A multiscale analysis of liver lobule fibrosis and its impact on drug propagation and metabolism - a DLA approach

Employing DLA methods, this paper explores the self-assembly of collagen fibers and resulting fibrosis at three scales up to the scale of regular lobule models. This allows a mechanistic exploration of the effects of collagen on drug transport (flow and diffusion) and metabolism. In addition, this method permits an analysis of fiber growth characteristics. First, variations of the DLA method of Parkinson et al (1994) will be used to generate multiple explicit collagen microfibril self-assembly using DLA particles in one dimension using cubic grid blocks of (4 mm)3 in a 240 x 20 x 20 grid model. The second stage will be to assess the consequences of various densities of these fibers in three dimensions on flow reductions at a higher scale. Here we utilize DLA methods in cubic grid blocks of (80 nm)3 to mimic 3D collagen self-assembly of fibrils. We then apply a pressure gradient or specified flow rates across a spatially gridded version of these models to quantify flow effects. This region represents a local zone of liver tissue affected by fibrosis. Analytic models of fibrotic effects on flow are employed for comparison. A third stage explores the implications of fibrosis in a liver lobule model using multiple grid blocks of size 3200 mm to represent the lobule tissue. Here, a continuum model of fiber density is employed, based on the previous two scales. The model also includes the effects of additional grid blocks representing sinusoidal flow paths found in the lobule. We contrast and quantify drug propagation and metabolism of molecular dissolved versus nanoparticle delivery vehicles in fibrotic media, achieved by upscaling explicit collagen distributions to appropriate average values.

physiology↗
bioRxiv2026

Pulmonary pressure load shapes right ventricular molecular remodelling in dilated cardiomyopathy

Right ventricular (RV) adaptation to pulmonary hypertension determines outcome in dilated cardiomyopathy (DCM), but the molecular mechanisms of the transition to decompensation remain unclear. We analysed RV tissue from explanted hearts of patients with end-stage DCM using single-nucleus RNA sequencing (n=21), mass spectrometry and Olink Reveal proteomics (both n=44), and integrated these molecular profiles with echocardiographic and right-heart catheterisation measures to identify molecular correlates of RV dysfunction. Mean pulmonary arterial pressure was the dominant correlate of RV transcriptional remodelling, particularly in cardiomyocytes, where higher pressure was associated with contractile remodelling, autophagy, vesicle trafficking and glucose metabolism. In contrast, RV decompensation was characterised by immune activation and reduced oxidative phosphorylation exclusively at the proteomic level. Integrative multi-omics factor analysis (MOFA) further identified fibrosis as the dominant molecular program shared across transcriptomic and proteomic layers. Together, these findings indicate molecular adaptation to pressure load and tissue fibrosis during progression towards RV failure.

physiology↗