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Understanding the cellular properties controlling neural stem and progenitor cell (NSPC) fate choice will improve their therapeutic potential. The electrophysiological measure whole-cell membrane capacitance reflects fate bias in the neural lineage but the cellular properties underlying membrane capacitance are poorly understood. We tested the hypothesis that cell surface carbohydrates contribute to NSPC membrane capacitance and fate. We found NSPCs differing in fate potential express distinct patterns of glycosylation enzymes. Screening several glycosylation pathways revealed that the one forming highly branched N-glycans differs between neurogenic and astrogenic populations of cells in vitro and in vivo. Enhancing highly branched N-glycans on NSPCs significantly increases membrane capacitance and leads to the generation of more astrocytes at the expense of neurons with no effect on cell size, viability, or proliferation. These data identify the N-glycan branching pathway as a significant regulator of membrane capacitance and fate choice in the neural lineage.

Competing Interests: Competing interests The BMJ has judged that there are no disqualifying financial ties to commercial companies. The authors declare the following other interests: none. Further details of The BMJ policy on financial interests are here: https://www.bmj.com/about-bmj/resources-authors/forms-policies-and-checklists/declaration-competing-interests

One of the commonly used parameters for evaluating aortic regurgitation is the rate of pressure decay data obtained from echocardiographic evaluation or cardiac catheterization. The measurement of the rate of equalization of pressure between the aorta and the left ventricle and its utility in the setting of aortic insufficiency has been validated. Intuitively, the Doppler equivalent, pressure half-time, is inversely related to the severity of regurgitation. However, this is a phenomenon dependent on multiple variables including blood pressure, heart rate, compliance of the receiving chamber, effects of vasopressors and the volume status of the patient. We report a case of unique hemodynamics obtained during cardiac catheterization due to low filling pressures that was further confounded by elevated systemic vascular resistance in a critically ill patient with angiographically severe aortic regurgitation.