Inner medullary lactate production and accumulation: a vasa recta model

Model Status

This CellML version of the model has been checked in COR and PCEnv and it runs in PCEnv. The model will not run in COR because it does not contain any time derivatives - COR expects the units of the differential equations to be a function of time (not length as it is in this case). However, COR did allow for the units to be checked and they are consistent. The model runs in PCEnv but as yet it does not recreate the published results. This may be due to differences in the defined set of initial conditions. The model author has been contacted and we are currently receiving their help and advice.

Model Structure

S. Randall Thomas here investigates the possibility that recycling of lactate produced by anaerobic glycolysis in the inner medulla of the kidney can provide sufficient of a lactate gradient to contributes significantly to the urine concentrating mechanism.

Assuming (from other sources) that 20% of the glucose delivered to the inner medulla, Thomas uses a mathematical model of the inner medullary vasa recta, based on observed mass distribution and distribution of loops, to investigate a range of plausible values of lactose and glucose permeabilities, to see which values would allow a sufficient accumulation of a lactate gradient to be a significant contributor to urine concentrating ability, in different circumstances of blood flow and diuresis.

The complete original paper reference is cited below:

Inner medullary lactate production and accumulation: a vasa recta model, S. Randall Thomas, 2000, American Journal of Physiology, 279, F468-F481. PubMed ID: 10966926

Schematic representation of the steady-state model.