Sex-Specific Differences in LPS-Induced Rapid Myocardial Dysfunction

Area of Science:

• Cardiovascular Biology
• Immunology
• Mitochondrial Medicine

Background:

• Sepsis-induced cardiac dysfunction significantly increases mortality.
• Females generally exhibit better cardiac function than males post-sepsis.
• Tumor necrosis factor-alpha (TNFα) elevation post-sepsis may mediate sex differences in cardiac dysfunction.

Purpose of the Study:

• To investigate sex differences in direct effects of lipopolysaccharide (LPS) on cardiac function.
• To determine if LPS directly impacts myocardial function differently between sexes.
• To explore the role of oxidative phosphorylation (OXPHOS) and estrogen receptors (ERs) in sex-based LPS responses.

Main Methods:

• Isolated male and female mouse hearts were perfused using the Langendorff method.
• Lipopolysaccharide (LPS) was infused, and left ventricular developed pressure (LVDP) was monitored.
• Western blot analysis was used to assess OXPHOS proteins and ERs in heart tissue.

Main Results:

• Male hearts showed significantly worse LV function than female hearts after LPS infusion.
• No significant differences in cardiac function or ER expression were found across female estrous cycle stages.
• OXPHOS protein levels differed between male and female hearts post-LPS, suggesting sex-specific mitochondrial responses.

Conclusions:

• Male hearts are more susceptible to rapid LPS-induced cardiac dysfunction than female hearts.
• Estrogen appears to have a limited role in modulating the rapid functional depression caused by LPS.
• Sex differences in myocardial mitochondrial responses, particularly via the OXPHOS pathway, warrant further investigation in direct LPS insult.