Key Points
- To determine whether pressure-dependent inhibition of proximal tubule fluid reabsorption enhances tubuloglomerular feedback efficacy sufficiently to mediate renal autoregulation.
- Derived mathematical models of glomerular and tubular fluid dynamics representing superficial and juxtamedullary nephrons.
- Coupled tubular flow rate at the late proximal tubule or macula densa to afferent arteriolar resistance through a tubuloglomerular feedback function across varying arterial pressures.
- Tubuloglomerular feedback operating alone accounted for approximately one-half of renal blood flow and glomerular filtration rate autoregulation.
- Pressure-dependent inhibition of proximal reabsorption increased tubuloglomerular feedback efficacy, matching published whole-kidney autoregulation values at pressures up to 130 mmHg.
- Autoregulatory compensation from this proximal tubule-tubuloglomerular feedback interaction was exhausted above 130 mmHg, indicating that additional mechanisms are required at higher arterial pressures.
Structured PICO
PPopulationComputational models describing pressure and flow in a glomerulus and a nephron
IInterventionModeling pressure-dependent inhibition of proximal tubule fluid reabsorption coupled with tubuloglomerular feedback (TGF)
CComparatorModels assuming constant reabsorption in the proximal tubule (TGF alone)
OOutcomeGlomerular filtration rate (GFR) and renal blood flow autoregulationsurrogate
Computational modeling suggests that proximal tubule-TGF interactions can adequately explain renal autoregulation up to arterial pressures of 130 mmHg.
Limitations
- The effect of the interaction is spent at arterial pressures greater than 130 mmHg, indicating additional mechanisms are required to extend this range.