Borrowing photosynthesis
A spinach leaf turns light into chemical energy. A failing heart cannot. Researchers at Union Hospital of Huazhong University of Science and Technology in Wuhan set out to test whether part of the leaf's energy-making machinery could be moved into heart muscle cells.
The team, led by Haohui Fan, extracted thylakoid membranes from spinach leaves, the structures where photosynthesis takes place, and engineered them into nanoparticles. The particles were coated with membranes taken from heart muscle cells before being injected into the hearts of rats with experimentally induced heart failure.
The paper is titled "Cardiomyocyte Membrane-Camouflaged Spinach Nano-Thylakoids Enhance Myocardial Energy Metabolism and Ameliorate Heart Failure" and appears in the journal Small, with the DOI 10.1002/smll.76087.
Results in rats
When the treated animals were also exposed to red light, their hearts pumped better and showed less tissue damage, according to the paper. The authors say the plant membranes supply extra energy to heart cells that are starved of it, while the cell-derived coating helps the particles survive in the tissue long enough to work.
The study was small and in animals, and the animals received injections straight into the heart muscle, which is not a practical route for routine care. The researchers had to illuminate the tissue, and it is still not clear whether enough light can reach a human heart sitting deep inside the chest.
A long path to patients
Plant membranes have been engineered into particles before for eye and skin conditions, but delivering light to an internal organ is the central obstacle. Independent scientists described the work as an unusual proof of concept rather than a coming therapy.
Heart failure affects millions of people worldwide and remains a leading cause of hospital admissions. Even a partial route to boosting the energy available to heart muscle would draw interest from cardiologists, but trials in larger animals and safety work on immune response would come first.