Immune Response Mediates Cardiac Dysfunction after Traumatic Brain Injury.

Area of Science:

• Immunology
• Cardiology
• Neurology

Background:

• Cardiovascular complications frequently follow traumatic brain injury (TBI), significantly increasing morbidity and mortality.
• The role of the immune system in mediating cardiac dysfunction after TBI remains an area of active investigation.

Purpose of the Study:

• To investigate the impact of the immune system, specifically the spleen, on cardiac dysfunction following TBI in a mouse model.
• To evaluate the therapeutic potential of splenectomy in mitigating TBI-induced cardiac complications.

Main Methods:

• Adult male C57BL/6J mice underwent controlled cortical impact (CCI) TBI, with or without immediate splenectomy.
• Cardiac function was assessed via echocardiography; neurological and cognitive functions were tested.
• Cardiac tissue analysis included flow cytometry, immunostaining for apoptosis, inflammation, oxidative stress, hypertrophy, and fibrosis.

Main Results:

• TBI induced significant cardiac dysfunction, characterized by reduced ejection fraction and fractional shortening, alongside increased cardiomyocyte apoptosis, inflammation, and oxidative stress.
• Splenectomy in TBI mice markedly improved cardiac function and decreased cardiac fibrosis, oxidative stress, apoptosis, immune cell infiltration, and inflammatory markers.
• Neurological and cognitive deficits post-TBI were severe, and splenectomy did not ameliorate these neurological outcomes.

Conclusions:

• TBI triggers cardiac dysfunction through immune cell infiltration and inflammatory factor expression in the heart.
• Splenectomy mitigates cardiac inflammation and improves cardiac function post-TBI, highlighting the immune response's contribution to cardiac dysfunction.