Growing Blood Vessels

The advances taking place ontissues today are jaw dropping.  We areapproaching the capability to trade out failed parts of the body as a matter ofroutine surgery.  They will be replacedwith new components reconstructed using ones own cells.

I recently saw the demonstrationof a swine kidney on NOVA been cleansed of all swine cells that could then beused to house human cells and be then transplanted into a human in need.  They have already achieved something like allthis with the heart.  They got the resultbeating!  Importantly, the time from recognizingpossibility to demonstration was quick. This should have had an unending series of glitches.  This means that perfecting all this is goingto be rapid and decades have already become years and probably we are actuallydealing in months.

What is have actually seen thispast couple of years tells me that the available tool kit is already sufficientto systematically restore the majority of the human body.  It will soon be into the tweaking stage.

This item tells us that aremaining road block is on the way to been removed.  We have now successfully grown blood cells.

blood vessels for lab-grown tissues

Rice, BCM discovery addresses key roadblock to growing replacement tissues,organs

Researchers from Rice University and Baylor Collegeof Medicine (BCM) have broken one of the major roadblocks on the path togrowing transplantable tissue in the lab: They've found a way to grow the bloodvessels and capillaries needed to keep tissues alive.

The new research is available online and due to appear in the Januaryissue of the journal Acta Biomaterialia.

"The inability to grow blood-vessel networks -- or vasculature --in lab-grown tissues is the leading problem in regenerative medicinetoday," said lead co-author Jennifer West, department chair and the IsabelC. Cameron Professor of Bioengineering at Rice. "If you don't have bloodsupply, you cannot make a tissue structure that is thicker than a couple hundredmicrons."

As its base material, a team of researchers led by West and BCMmolecular physiologist Mary Dickinson chose polyethylene glycol (PEG), anontoxic plastic that's widely used in medical devices and food. Building on 10years of research in West's lab, the scientists modified the PEG to mimic thebody's extracellular matrix -- the network of proteins and polysaccharides thatmake up a substantial portion of most tissues.

West, Dickinson, Rice graduate student Jennifer Saik, Riceundergraduate Emily Watkins and Rice-BCM graduate student Daniel Gould combinedthe modified PEG with two kinds of cells -- both of which are needed forblood-vessel formation. Using light that locks the PEG polymer strands into asolid gel, they created soft hydrogels that contained living cells and growthfactors. After that, they filmed the hydrogels for 72 hours. By tagging eachtype of cell with a different colored fluorescent marker, the team was able towatch as the cells gradually formed capillaries throughout the soft, plasticgel.

To test these new vascular networks, the team implanted the hydrogelsinto the corneas of mice, where no natural vasculature exists. After injectinga dye into the mice's bloodstream, the researchers confirmed normal blood flowin the newly grown capillaries.

Another key advance, published by West and graduate student JosephHoffmann in November, involved the creation of a new technique called"two-photon lithography," an ultrasensitive way of using light tocreate intricate three-dimensional patterns within the soft PEG hydrogels. Westsaid the patterning technique allows the engineers to exert a fine level ofcontrol over where cells move and grow. In follow-up experiments, also incollaboration with the Dickinsonlab at BCM, West and her team plan to use the technique to grow blood vesselsin predetermined patterns.

The research was supported by the National Science Foundation and theNational Institutes of Health. West's work was conducted in her lab at Rice'sBioScience Research Collaborative (BRC). The BRC is an innovative space wherescientists and educators from Rice University and other Texas Medical Center institutions worktogether to perform leading research that benefits human medicine and health.

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