A new model of experimental diabetic cardiomyopathy using combination of multiple doses of anomer-equilibrated streptozotocin and high fat diet: sex matters.

Diabetes mellitus (DM) leads to a more rapid development of DM cardiomyopathy (dbCM) and progression to heart failure in women than men. Combination of high-fat diet (HFD) and freshly-injected streptozotocin (STZ) has been widely used for DM induction, however emerging data shows that anomer-equilibrated STZ produces an early onset and robust DM model. We designed a novel protocol utilising a combination of multiple doses of anomer-equilibrated STZ injections and HFD to develop a stable murine DM model featuring dbCM analogous to humans. Furthermore, we examined the impact of biological sex on the evolution of cardiometabolic dysfunction in DM. Our study included six experimental protocols (8 weeks) in male and female C57BL/6J mice (n=109): Fresh STZ+HFD, Anomer-equilibrated STZ+HFD, HFD, Fresh STZ, Anomer-equilibrated STZ, Control diet+vehicle. Animals were characterised by extensive phenotyping in vivo and ex vivo. Anomer-equilibrated STZ+HFD led to induction of stable experimental murine DM characterised by impaired glucose homeostasis, cardiometabolic dysfunction and altered metabolome of liver, skeletal muscle, kidney and plasma. dbCM was more severe in female mice including systolic dysfunction and reduced cardiac energy reserve. This study established a novel, robust model of inducible murine DM and emphasised the impact of biological sex on DM progression and severity.