The assessment of cortical hemodynamic responses induced by tubuloglomerular feedback using in vivo imaging

The tubuloglomerular feedback (TGF) mechanism is crucial in modulating renal hemodynamics and glomerular filtration rate in individual nephrons. Our study aimed to evaluate the TGF-induced vascular responses by comparing the effects of two transport inhibitors with different sites and mechanisms of action. We assessed cortical hemodynamics with high-resolution laser speckle contrast imaging, which enabled the evaluation of blood flow individual micro-vessels and analysis of their dynamical patterns in the time-frequency domain. We demonstrated that a systemic administration of a loop diuretic abolishes TGF-mediated hemodynamic responses. Furthermore, we showed that the local microcirculatory blood flow decreased, and the TGF reset in response to reduced proximal reabsorption elicited by systemic administration of a sodium-glucose co-transporter 2 inhibitor, phlorizin.