Cardiovascular Disease Following Pregnancy in Mice Treated with an Insulin Receptor Antagonist

Background: Women with gestational diabetes mellitus (GDM), a condition of pregnancy-induced hyperglycemia, are more likely to develop cardiovascular disease (CVD) within 3 to 10 years following pregnancy. One reason for the lack of progress into the cardiovascular complications of GDM is the need for appropriate preclinical models that mimic human GDM. We have previously used the insulin receptor antagonist (S961) to develop a novel hormonal mouse model of reversible GDM. Hypothesis: We hypothesized that S961-induced GDM mice will exhibit CVDs later in life. Aim: To determine the mechanisms underlying CVD in hormonal model of GDM. Methods: Sixteen (16) week-old C57BL/6J female mice were treated with S961 or saline (n=4) from the second trimester of pregnancy until delivery to develop hormonal mouse model of GDM. Animals were followed up to 10 weeks after gestation. Blood glucose levels were measured with a glucometer. Fasting insulin, circulating endothelin-1 (ET-1) and nitrite were measured by colorimetry. Cardiac structure and function were measured by high resolution ultrasound echocardiography (VEVO 3100) and pulse wave velocity was measured by Pulse Wave Doppler (Indus instrument). Exercise tolerance test was performed on treadmill (Columbus Instrument). Aortic sirtuin-1 (SIRT-1) and ETA receptor were determined by western blot. Vascular reactivity was determined by wire myograph (DMT). Aortic fibrosis and calcification were determined by picrosirius red and Von Kossa staining. Data were analyzed by unpaired t- tests and results are expressed as mean ± standard error of mean. Results: S961-induced GDM mice exhibit hyperglycemia (169.5 ± 3.6 vs. 105.5 ± 10.8mg/dL, p<0.004 ) and hyperinsulinemia (1.9 ± 0.2 vs. 0.8 ± 0.1ng/ml , p<0.01 ) which mimics the condition observed in human GDM. Interestingly, S961-induced GDM mice went on to develop systolic and diastolic dysfunction, vascular stiffness (3.7 ± 0.1 vs. 3.1 ± 0.08 m/s, p <0.005 ), exercise intolerance and increased thickness of the cardiac wall at 10 weeks post-delivery. Plasma ET-1 was elevated in our model during pregnancy (28.1 ± 1.7 vs. 5.2 ± 0.2pg/ml, p <0.002 ) and at 10 weeks post-delivery (19.9 ± 2.9 vs. 6.7 ± 0.7pg/ml, p <0.05 ). Circulating NO and aortic expression of SIRT-1, that is involved in endothelial longevity by regulating endothelial NO synthase, is reduced in GDM mice. Vascular relaxation to acetylcholine was impaired in S961-induced GDM compared to control. Additionally, GDM mice exhibited increased arterial wall thickness, collagen accumulation, and calcium deposits in the wall of aorta. Conclusion: Insulin receptor antagonist (S961)-treated mice develop GDM similar to that observed in pregnant women. Moreover, S961 treated mice develop cardiac dysfunction and vascular stiffness at 10 weeks post-delivery. Alterations in ET-1, SIRT-1, NO levels, aortic fibrosis and calcification may be responsible for the development of CVD in this model. Funding: NIH-NIDDK (1R01DK121748-01A1), AHA Postdoctoral Award (23POST1020493), NIH-COBRE Pilot Grant (SP15081) and NIGMS (P20GM104357 & P30GM149404 ). 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.