Fantastic voyage into the heart
According to the Journal of Clinical Investigation (JCI), researchers from the Harvard Medical School have written a sequel to "Fantastic voyage," the 1966 sci-fi movie. By injecting self-assembling peptide nanofibers loaded with pro-survival factors into rats, they've showed that the animals could be protected from heart failures. So far, the researchers have not extended their experiments to humans.
Here is an excerpt from the JCI news release.
Narrowed or blocked blood vessels are unable to deliver sufficient levels of oxygen to cardiomyocytes, which results in cardiomyocyte death, loss of the middle layer of the heart wall (the myocardium), and ultimately, heart failure. Therefore, therapies that protect cardiomyocytes from death may help prevent heart failure.
In normal heart tissue, cardiomyocytes are surrounded by an intricate network of capillaries, and interaction of cardiomyocytes with endothelial cells that line the vessel wall and secrete PDGF-BB is integral to cardiomyocyte development and function.
[Note: PDGF stands for "Platelet-derived growth factor" and is is one of the numerous proteins that regulate cell growth and division according to Wikipedia.]
Below are several images showing how the injection of nanofibers (NF) with PDGF-BB decreases cardiomyocyte death after infarction (Credit: Harvard Medical School). Here is the scientific explanation: The "immunofluorescence staining of cleaved caspase-3 in cardiomyocytes (yellow areas) was shown in sections from 1 day after injection of NFs with or without P100. Blue, DAPI; red, α-sarcomeric actinin; green, cleaved caspase-3."
The research work has been published online by the 'Journal of Clinical Investigation' as an advanced publication on December 15, 2005 under the title "Controlled delivery of PDGF-BB for myocardial protection using injectable self-assembling peptide nanofibers." Here is a link to the abstract. Here is an excerpt from this abstract.
A blinded and randomized study in 96 rats showed that injecting nanofibers with PDGF-BB, but not nanofibers or PDGF-BB alone, decreased cardiomyocyte death and preserved systolic function after myocardial infarction. A separate blinded and randomized study in 52 rats showed that PDGF-BB delivered with nanofibers decreased infarct size after ischemia/reperfusion.
These data demonstrate that endothelial cells protect cardiomyocytes via PDGF-BB signaling and that this in vitro finding can be translated into an effective in vivo method of protecting myocardium after infarction. Furthermore, this study shows that injectable nanofibers allow precise and sustained delivery of proteins to the myocardium with potential therapeutic benefits.
And if you have a solid medical background, here is a link to the full paper (PDF format, 12 pages, 3.19 MB). The above illustration was extracted from this paper.
Finally, and even it's unrelated, you should pay a visit to the Nanomedicine Art Gallery assembled by the Foresight Nanotech Institute about Isaac Asimov's Fantastic Voyage -- even if Asimov wrote only a novelization of the movie and didn't participate to the original screenplay.
Sources: Journal of Clinical Investigation news release, December 15, 2005; and various web sites
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