Assessment of changes in glomerular permeability to albumin in rat models of glomerular disease

Hypertension (HTN) and diabetes mellitus (DM) are the primary causes of proteinuria and chronic kidney disease. However, it is difficult to determine the relative importance of changes in the filtration of protein versus reuptake due to the lack of an efficient method to measure changes in glomerular permeability. The present study examined the ability of a new dilutional fluorescent technique to detect changes in the glomerular permeability to albumin in models of HTN (Fawn hooded‐hypertensive (FHH) and Dahl S rats) and DM (STZ and T2DN rats) induced glomerular injury. The rats were treated with a high molecular weight marker in vivo and the glomeruli were isolated. Changes of the fluorescent signal in the glomerular capillaries in response to an imposed oncotic pressure gradient was used to determine dσAlb. The results presented below indicate that dσalb is reduced in various models of renal injury and that the changes correlate with the severity of proteinuria and renal injury. NIH HL36279, 29587 and DK.Treatment Age (weeks) Number of animals Number of glomeruli Proteinuria (mg/day) (mean±SE) Dσalb (mean±SE) Change of dσalb compared to SDSD 12 12 206 6.4±3.6 0.8±0.06 0 FHH 9 8 82 93±9 0.49±0.08 39%↓ Dahl S (low salt) 9 5 43 44±8 0.73±0.04 9%↓ Dahl S (high salt) 9 5 64 330±40 0.39±0.04 51%↓ STZ 10 8 135 160±23 0.53±0.06 34%↓ T2DN 24 4 69 40±5 0.67±0.06 16%↓