Dietary vitamin D supplementation partially rescues heart rate in Ts65Dn mice, a model of Down syndrome

Down syndrome is the most common developmental and intellectual disability that leads to co-morbidities including lower heart rate and blood pressure. We previously showed that Ts65Dn mice also display reduced heart rate and blood pressure compared to wild-type (WT) colony controls. Lower serum Vitamin D (VitD) levels have been reported among individuals with Ds. In other populations, VitD is a regulator of nitric oxide synthase and a known modulator of cardiovascular outcomes. VitD effects on cardiovascular physiology in Ds is unknown. In this preliminary study, we hypothesized that Ts65Dn mice supplemented with VitD would display improved heart rate compared to Ts65Dn mice on a control diet. Two-month old male Ts65Dn mice were placed onto a control diet (1IU VitD/g; n=4) or VitD supplemented diet (50IU/g; n=5) for two weeks and subsequently tested for resting heart rate. Mice were fitted with a MouseOx neck collar to monitor heart rate while freely moving within the cage. After habituation to the collar, heart rate was recorded for 30 minutes in the light cycle. Heart rate in Ts65Dn on the control diet was 510±67 bpm vs. 636±78 on the VitD diet (p=.038; t-test). As expected, WT (n=5; control diet) displayed a higher heart rate of 729±62 bpm. These preliminary data reveal a partial rescue of resting heart rate in Ts65Dn following VitD supplementation. Future studies can evaluate serum VitD levels, nitric oxide synthase, and cardiovascular metrics including blood pressure, heart rate, and pulse wave velocity in Ts65Dn and WT mice supplemented with dietary VitD. This work was supported by NIH R21HD099573 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.