Lab-Grown Blood Vessel Replacements Move Closer to Clinical Trials

Lab-Grown Blood Vessel Replacements Move Closer to Clinical Trials

A major development has been announced by researchers at the University of Minnesota, who have successfully used lab-grown blood vessel replacements for kidney dialysis in non-human primates. There is hope that the lab-grown blood vessel replacements could be a viable alternative to autologous and prosthetic arteriovenous grafts for kidney dialysis patients.

Treating patients suffering from renal failure requires the use of hemodialysis. Each year more than 100,000 people in the U.S. start hemodialysis following a diagnosis of kidney disease, and across the United States, 400,000 people receive hemodialysis each year.

Patients often receive an arteriovenous fistula which connects a vein to an artery, although the surgical procedure is not always successful. 30-50% of patients experience complications and require vein grafts. For patients with compromised vasculature, an arteriovenous fistula is not an option.

Autologous vein grafts are preferred as the use of prosthetic arteriovenous grafts (AVGs) carries an increased risk of infection and prosthetic AVGs are associated with inferior primary patency rates.

The researchers sought an alternative to autologous vein grafts, and used tissue engineering to develop an entirely biological alternative, using sacrificial fibrin scaffolds and human fibroblasts. They are the first blood vessel replacements that consist entirely of biological materials. However, remarkably, these blood vessel replacements do not contain any living cells, at least, not at the point that they are implanted.

The researchers point out that their lab-grown blood vessel replacements are both entirely biological and nonliving, and offer surgeons an “off-the-shelf” alternative to prosthetic AVGs, and results more comparable to autologous AVGs.

The researchers have already conducted a successful trial in sheep, but required a more human-like model and conducted a trial in baboons, using the 15cm-long decellularized grafts as hemodialysis access points.

The researchers report that after 6 months, the grafts were recellularized with host cells, had the appearance of normal blood vessels, and were capable of withstanding more than 30 times the normal human blood pressure without bursting. The researchers said there was no observed calcifications, and no overt immune response or outflow stenosis. These are common failure modes in other graft materials.

The research team, headed by University of Minnesota Department of Biomedical Engineering Professor Robert Tranquillo, is now seeking FDA approval for a clinical trial using the lab-grown blood vessel replacements in humans.

The research – A completely biological “off-the-shelf” arteriovenous graft that recellularizes in baboons – was recently published in the journal Science Translational Medicine.

Leave a Reply