New research from Northwestern Medicine reveals a significant difference in how the immune system repairs heart damage in newborns compared to adults. The study, conducted on experimental animals, indicates that newborns can regenerate cardiac tissues due to their immune systems' unique functions, while adults tend to develop scar tissue after heart attacks.
Connor Lantz, the lead scientist at the Comprehensive Transplant Center at Northwestern University Feinberg School of Medicine, stated, "Understanding why newborns can regenerate their hearts while adults cannot will open the door to developing treatments that could ‘reprogram’ adult macrophages." This research suggests potential future therapies aimed at enhancing adult heart repair by mimicking newborn immune responses.
The study focused on macrophages and their role in repairing heart tissue. In newborns, these immune cells engage in efferocytosis, which involves consuming dying cells and producing thromboxane. This bioactive lipid encourages heart muscle cells to divide and repair damage. In contrast, adult macrophages generate less thromboxane, resulting in limited healing capabilities.
Lantz noted the potential of improving tissue repair by simulating thromboxane effects: “By mimicking the effects of thromboxane, we might one day improve tissue repair after a heart attack in adults.”
The researchers studied mice at different ages to observe variations in immune response. Newborn mice showed enhanced ability to engulf dying cells due to higher expression of MerTK receptors. Blocking this receptor impaired their regenerative abilities. The findings indicate that newborn macrophages produce thromboxane A2 more effectively than adult ones, leading to better recovery outcomes.
The study titled "Early Age Efferocytosis Directs Macrophage Arachidonic Acid Metabolism for Tissue Regeneration" is set for publication on February 11 in Immunity. Edward B. Thorp from Feinberg is also a co-corresponding author of the study.
This research received funding from multiple sources including the American Heart Association and National Institutes of Health.