Zhang, Junmeng

Cardiovascular (CV) dysfunction is common in severe acute pancreatitis (AP) and contributes substantially to mortality. Although sex differences in CV diseases are well recognized, with males generally exhibiting higher risk and poorer outcomes, their influence on AP-associated CV responses remains poorly defined. Here, we examined sex-dependent alterations in vascular integrity and cardiac function using cerulein-induced mouse models of AP. Because obesity is associated with more severe forms of AP, cerulein was used to induce mild AP in lean wild-type C57BL/6J mice and a more severe phenotype in obese C57BL/6J mice. Across both models, pancreatic injury was comparable between sexes. A modest sex difference in vascular permeability was observed in the mild but not severe AP model. In mild AP, both males and females showed similar compensatory increases in cardiac systolic function; however, in severe AP, only female mice maintained this adaptive systolic augmentation. Circulating levels of free fatty acids, reflecting systemic tissue lipolysis, were lower in females. Impaired cardiac adaptation in males was accompanied by higher levels of seven different myocardial inflammatory cytokines, as well as elevated circulating levels of angiopoietin-2 (Angpt2). While Angpt2 levels correlated with the severity of cardiac dysfunction, Angpt2 neutralization did not improve, and indeed worsened cardiac function in males. Together, these findings delineate both sex-dependent and sex-independent CV responses in mild and severe AP and identify Angpt2 as a potential compensatory cardioprotective factor under obesity-associated severe AP.

Background: Alterations in cardiovascular function are key features of severe acute pancreatitis (AP) and contribute substantially to mortality. Although sex differences in cardiovascular diseases are well recognized, with males generally exhibiting higher risk and poorer outcomes, their influence on AP-associated cardiovascular responses remains poorly defined. Therefore, we hypothesized that cerulein-induced AP causes severity-dependent and sex-specific changes in vascular integrity and cardiac function. Methods: Obesity has been associated with more severe forms of AP. Thus, mild and severe AP were induced by cerulein injections (100µg/kg/h×12) in lean (n=10 males, n=13 females) and obese (n=9 males, n=12 females) C57BL/6J mice, respectively. Vascular permeability was assessed by FITC-dextran extravasation. Cardiac function was assessed by echocardiography before and after cerulein injection. Cytokines were measured with multi-plex cytokine array and the role of angiopoietin-2 (Angpt2), an endothelial-derived regulator of vascular and cardiac responses, was evaluated using a neutralizing antibody. Results: Vascular permeability did not differ significantly between sexes in either AP model. In mild AP, males and females showed comparable increases in systolic function; however, in severe AP, only female mice maintained this adaptive systolic augmentation, assessed by fractional shortening (FS; 25.78±0.27% at baseline vs. 43.44±0.57% at endpoint, n=12, p<0.0001). This impaired cardiac adaptation in males was accompanied by increased myocardial inflammatory cytokines and elevated circulating free fatty acids. Among ten circulating cytokines measured, Angpt2 levels were significantly higher in males than females (male: 63.50±1.52ng/mL, n=9 vs. female: 41.37±2.68ng/mL, n=6, p=0.013) and were negatively correlated with systolic performance (FS; R 2 =0.75, p<0.0001), while positively associated with preload (end-diastolic volume; R 2 =0.55, p=0.0015). Unexpectedly, Angpt2 neutralization did not improve the cardiac adaptations in males and instead worsened cardiac performance as reflected by reduced FS (control IgG: 32.83±1.47%, n=4 vs. Anti-Angpt2: 22.88±0.64%, n=5, p=0.013) in severe AP. Conclusions: AP elicits both sex-dependent and sex-independent cardiovascular responses, with female mice exhibiting preserved cardiac adaptation, and Angpt2 is a potential compensatory mediator of cardiac protection in severe AP.