Multiparity has beneficial effects on vascular function in an experimental model of type 2 diabetes

Background: Correlational studies have showed that parity is associated with risk for cardiovascular disease (CVD). According to these correlations, multiparous women have reduced risk of developing CVD compared to nulliparous women. Experimental studies examining the effects of parity on vascular function are lacking and most importantly, how parity affects women with established cardiovascular risk factors is unknown. Women with type 2 diabetes have a greater risk of developing vascular complications compared to their non-diabetic counterparts. This study focuses on the influence of parity on contractile arterial responses of multiparous and nulliparous rats with type 2 diabetes. Hypothesis: Old multiparous rats with type 2 diabetes (Goto-Kakizaki rats, GK) were hypothesized to have a decreased contractile response to phenylephrine (PE) and endothelin-1 (ET-1) compared to nulliparous GK young and age-matched rats. Materials and Methods: Three experimental groups were used: GK young nulliparous rats, 20 weeks old (GK Young NP); GK old nulliparous rats, 60 weeks old (GK Old NP); and GK old multiparous rats, 60 weeks old (GK Old MP). Mesenteric resistance arteries (MA) were mounted in a wire myograph to measure the contractile responses to PE (10-9 – 3x10-5 M) and ET-1 (10-11 – 10-7 M). Results: GK Old MP rats were heavier compared to GK Old and GK Young NP rats (297 ± 7 g vs. 255 ± 11 g vs. 232 ± 4 g, p0.05). Mesenteric arteries from GK Old MP rats had reduced sensitivity (-logEC50) to ET-1 compared to arteries from GK Old NP and GK Young NP groups (7.82 ± 0.11 vs. 8.45 ± 0.08 vs. 8.24 ± 0.07, p Conclusions: Nulliparity may have adverse effects on vascular function in women with type 2 diabetes. Taking a parity history may be beneficial when evaluating women with type 2 diabetes for risk of developing CVD.