Subtle changes in cardiac function correlates with changes in mitochondrial function following chronic exposure a biological relevant dose of polystyrene nanoplastics

Nanoplastics are emerging as a substantial risk factor for cardiovascular disease. Previous data from our laboratory has also shown that mitochondrial dysfunction is closely linked to the pathophysiology of cardiovascular disease. Current estimates are that approximately 13.2 billion tons of plastic waste will be present in the environment by 2050, thus emphasizing the dire need to develop preclinical studies for the investigation of nanoplastic-induced cardiovascular dysfunction. However, while conventional assessment has been shown, no study till date has established how chronic exposure to a biologically relevant dose of polystyrene nanoplastics (PSNPs) affects the different regions of the left ventricle. Hence, the objectives of this study were to determine whether the use of speckle-tracking based imaging could detect subtle changes in cardiac contractile function, and to determine whether mitochondrial integrity was compromised in the PSNPs-exposed group compared to control. To evaluate this, we tested the hypothesis that using speckle-tracking based imaging and mitochondrial structural indices captures transient and progressive cardiac contractile dysfunction following chronic PSNPs exposure. 5mg/L of PSNPs (100nm) supplemented in drinking water was administered to FVB/NJ male mice (15-week-old), daily for 30 weeks. Initial studies assessed cardiac function utilizing speckle-tracking based strain imaging at 6 weeks and 30 weeks following PSNPs exposure. Further, using flow-cytometry and spectrophotometry, mitochondrial structure and electron transport chain complex activities were evaluated post-exposure, respectively. Segmental analyses on the left ventricle revealed decrease in anterior and septal free wall region in the short axis when assessing circumferential strain parameters (p< 0.05 for both). Preliminary data on mitochondrial structural indices using flow cytometry revealed an increasing trend in mitochondria size (p=0.068) in PSNPs group compared to the control group. Also, there was a decreasing trend in Complex III and IV activity (p=0.069 and 0.057) respectively following chronic exposure in PSNPs when compared with control. Taken together, these findings suggest that chronic exposure to a biologically relevant dose of PSNPs might alter mitochondrial structure and function. Overall, the use of speckle-tracking based imaging might serve as a better approach for evaluating cardiac contractile function and assist in identifying specific left ventricular regions affected following chronic PSNPs exposure. Support or Funding information This work was supported by: National Institutes of Health Grants R01-ES-034628, R01-HL-168290, and Community Foundation for the Ohio Valley Whipkey Trust. This abstract was presented at the American Physiology Summit 2026 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.