The Benefits of Time-Restricted Feeding on the Kidneys are Blunted in Aged Mice

Age-induced structural changes in the kidney lead to functional decline, which causes the elderly to be more vulnerable to various acute or chronic kidney disorders. Time-restricted feeding (TRF) has been linked to improved cardiovascular and renal health. We hypothesized that aged male mice have improved renal health and function following time-restricted feeding using a high salt diet. These studies included eighteen-month-old male C57BL/6 mice. Standard (0.4% NaCl) or high salt (4.0% NaCl) diets were provided for 4 weeks ad libitum (AL) or access to food was restricted to 8 hours during the midpoint of their active periods. Glomerular filtration rate (GFR) was measured using transdermal sensors. Kidneys were harvested at the beginning of the inactive period for flow cytometry analysis. There was no difference in 24-hour food intake between ad libitum and TRF aged mice on a standard diet (AL: 15.0 ± 1.2; TRF: 14.6 ± 1.9 pellets; P=NS; N=7-8). There were fewer renal immune cells following TRF compared to ad libitum (P=0.0029; N=5). When placed on a high salt diet, there was no difference in 24-hour food intake between ad libitum and TRF mice (AL: 288 ± 44; TRF: 289 ± 52 µl/min; P=NS; N=5). There was no difference in GFR between each group (AL: 13.3 ± 0.7; TRF: 12.6 ± 1.2 pellets; P=NS; N=5). Additionally, there was no difference in renal immune cells following TRF with a high salt diet compared to ad libitum (P=NS; N=5). In conclusion, time-restricted feeding using a standard diet leads to decreased renal inflammation in aged mice. However, the anti-inflammatory effect of time-restricted feeding is lost when a high-salt diet is consumed in aged mice. These findings suggest that the anti-inflammatory effect of time-restricted feeding is more preventative than curative. NIH: K01 DK135929-01A1; AHA: 23SCEFIA1157124 This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.