Healthy hearts are adaptable, and heartbeats exhibit complex variation as they adjust to tiny changes in the body and environment. Mass General Brigham researchers have applied a new way to measure the complexity of pulse rates, using data collected through wearable pulse oximetry devices. The new method, published in Journal of the American Heart Association, provides a more detailed peek into heart health than traditional measures, uncovering a link between reduced complexity and future cognitive decline.

In a new study, researchers from Mass General Brigham identified a natural “brake” within the innate immune system: the inhibitory receptor Siglec-E (SigE) and its human counterparts, Siglec-7 and Siglec-9. This receptor helps prevent overactivation of immune cells that drive rejection. When this brake is missing, inflammation worsens, leading to faster rejection in preclinical models. Importantly, transplant patients with higher levels of Siglec-7 and Siglec-9 showed better graft survival, highlighting this pathway as a promising target for new therapies. Results are published in Science Translational Medicine.