Diz, D. I. | bioRxiv Science

bioRxiv2024

Sex-Specific Cardiovascular Adaptations to Simulated Microgravity in Sprague-Dawley Rats

Men and women have different cardiovascular responses to spaceflight; however few studies have focused on direct comparisons between sexes. Therefore, we investigated cardiovascular system differences, including arterial stiffness between socially and sexually mature 20-week-old male and female Sprague Dawley (SD) rats exposed to hindlimb unloading (HLU) - an analogue for spaceflight-induced microgravity. Two weeks of HLU had no effect on body weight in either male or female rats. The index of arterial stiffness determined by ultrasound, pulse wave velocity (PWV), was greater in the aortic arch and carotid artery of females after HLU versus control females. HLU had no effect on arterial PWV in males. smooth muscle actin, myosin, collagen, elastin, and collagen-to-elastin ratio were not different in rats of either sex in response to HLU. HLU exposure did not alter individual collagen fiber characteristics in studied groups. The levels of G protein-coupled estrogen receptor (GPER) were lower in the aorta of SD females exposed to HLU compared with female controls but not in males. These changes were associated with lower PPAR {gamma} and increased oxidative stress markers (8-hydroxy-2-deoxyguanosine and p47phox) in the females. Diastolic cardiac function was altered in females after HLU versus control females. GPER agonist, G1 prevented the increase in pulse wave velocity and 8-hydroxy-2-deoxyguanosine, without altering PPAR {gamma} or p47phox. Our data revealed that lower GPER in the HLU females contributes to the development of arterial stiffness, and that the SD rat is a suitable model to study the cardiovascular response of females to HLU.

physiology↗

bioRxiv2021

Sulfonylureas target the neurovascular response to decrease Alzheimer's pathology

Hyperexcitability is a defining feature of Alzheimers disease (AD), where aberrant neuronal activity is both a cause and consequence of AD. Therefore, identifying novel targets that modulate cellular excitability is an important strategy for treating AD. ATP-sensitive potassium (KATP) channels are metabolic sensors that modulate cellular excitability. Sulfonylureas are KATP channel antagonists traditionally used to combat hyperglycemia in diabetic patients by inhibiting pancreatic KATP channels, thereby stimulating insulin release. However, KATP channels are not limited to the pancreas and systemic modulation of KATP channels has pleotropic physiological effects, including profound effects on vascular function. Here, we demonstrate that human AD patients have higher cortical expression of vascular KATP channels, important modulators of vasoreactivity. We demonstrate that peripheral treatment with the sulfonylurea and KATP channel inhibitor, glyburide, reduced the aggregation and activity-dependent production of amyloid-beta (A{beta}), a hallmark of AD, in mice. Since glyburide does not readily cross the blood brain barrier, our data suggests that glyburide targets vascular KATP channel activity to reduce arterial stiffness, improve vasoreactivity, and normalize pericyte-endothelial cell morphology, offering a novel therapeutic target for AD. Graphical abstractTargeting vascular KATP channel activity for the treatment of Alzheimers disease pathology. O_FIG_DISPLAY_L [Figure 1] M_FIG_DISPLAY C_FIG_DISPLAY

neuroscience↗