Abstract 465: Medical Device Materials and Blood Pressure Alterations in Mice

Abstract

Di-2-ethylhexyl phthalate (DEHP) is a plasticizer that is used to impart flexibility to polyvinyl chloride products. Patients have an increased exposure to phthalates through contact with DEHP-containing medical devices, including: storage bags containing blood, plasma, intravenous fluids, total parenteral nutrition, tubing associated with their administration, nasogastric tubes, enteral feeding tubes, catheters, extracorporeal membrane oxygenation (ECMO) circuits, hemodialysis tubing, respiratory masks and endotracheal tubes. Human health concerns pertaining to DEHP exposure are linked to its endocrine-disrupting properties. Accordingly, increased exposure has been associated with cancer, metabolic disturbances, reproductive and neurological disorders, and cardiovascular disease. As an example, epidemiological studies have shown a link between DEHP exposure and elevated systolic blood pressure in adolescents. Despite bans and restrictions on the use of DEHP-containing medical devices in other countries, there is currently no mandate from the Food & Drug Administration for the use of DEHP-free devices and storage containers. The objective of this study was to quantify the impact of in vivo DEHP exposure on cardiovascular function; thereby, providing additional information for regulatory decisions by the scientific, medical and regulatory community. Healthy C57BL/6 male mice were implanted with radiotelemetry transmitters; briefly, the transmitter catheter was placed in the carotid artery and biopotential leads were routed subcutaneously to collect electrocardiogram (ECG) signals. After surgical recovery, pre-exposure data was collected, and thereafter, animals were exposed to 0.2 mg/g DEHP or control diet. We observed a significant increase in systolic pressure in DEHP-treated (145 + 3 mmHg) vs control animals (136 + 1 mmHg). We also detected an increase in diastolic and mean arterial pressure in DEHP-treated (119 + 5 and 132 + 3 mmHg, respectively) vs control animals (107 + 2 and 121 + 2 mmHg). Our previous reports have shown that DEHP diminishes cardiac contractility, which suggests that these effects on blood pressure are likely attributed to alterations in sympathetic tone and/or an increase in vascular resistance.