Humacyte HAV

Stick it to me?

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Can you imagine what your life would be if your kidneys failed?  You would probably be forced to give up your job (see below for more) and spend 3 days a week going back and forth to a dialysis clinic, where you would be hooked up to a machine for about 4 hours each time.  And, you still would only have some of your kidney functions fixed, not all of them.

Given the fact that you would probably have to drive (or be driven) to and from each dialysis session, that you can’t just walk into a clinic and start treatment, we are talking about spending some 18 hours a week dealing with this process.  Now, you can see why you’d have to give up your job.   Unless, of course, you can convince your physician (and your insurance company that pays for the first 18 months of treatment) that you can dialyze at home.  Overnight.  For a better life.  For a chance at keeping your job.

But, that’s only part of the issue.  Because there is an issue with “dialysis access”.  After all, we are going to hook some tubes up to your body and suck blood out between 500 ml and 1 liter every single minute for that four hour treatment.  Those needles- large bore needles, I might add- have to puncture this access site repeatedly.

And, those sites get clogged, they get clotted, they get infected.  Which means we need a way to clean them.  We need to find a way to replace them.  Or, we need to find an alternate site to play Dracula with your blood.

This is exactly why a bunch of researchers have been trying to develop an improved method of dialysis access. One such international group published their findings in the Lancet (the esteemed British medical journal) recently.

Humacyte’s Jeffrey Lawson MD PhD, Marc Glickman MD, Alison Pilgrim MD PhD, and Heather Pritchard PhD; Medical University of Lublow’s Marek Ilzecki MD PhD, Andrzej Jarosynski MD PhD, Stanislaw Przywara MD PhD, and Tomasz Zubilewicz MD PhD; Medical University of Warsaw’s  Jacek Szmidt MD PhD and Tomasz Jakimowicz; General Hospital of Wroclaw’s Jakub Turek MD, Wojciech Witkiewicz MD PhD, Norbert Zapotoczny MD, Malgorzata Guziewicz MD PhD, Cardiovascular Associates of Houston’s Erik Peden MD, and Yale’s Laura Niklason MD PhD formed this experimental team.  (Please note that Dr. Niklason is a founder of Humacyte.)  I am sure you notice how high powered this group is (more than ½ were MD PhD’s).  The results of the tests, “Bioengineered human acellular vessels for dialysis access in patients with end-stage renal disease: two phase 2 single-arm trials”  were published on 16 May 2016.

The basis for the access was a human acellular vessel (HAV).  As opposed to many dialysis access sites, this was not derived from pig or bovine sources- or even sheep.  Those kinds of devices have to undergo cross-linking via glutaraldehyde to render the human immune response negligible. And, that means we humans can really repopulate or maintain the site via normal cellular means.   (Other folks have tried growing the patients’ own cells in vitro and then inserting them into the patient.  However, that is a very long, very expensive process.)

This development does come from human cells, but after they are grown into the device basis, they are “decellularized”.  This structure is then inserted into the patient and the non-living human derived tissue can be remodeled by the patient’s own cells.

As I have reported for various stem cell developments, these cells are grown on a degradable scaffold, shaped like a blood vessel..  But, they are not stem cells, but vascular cells obtained from human donors.  The cells are bathed in nturients and grown for eight (8) weeks, when the scaffold degrades and the engineered tissue remains- which is then decellularized.  When the cells are removed, all that is left is the protein structure- mostly collagen and some other non-living cellular components- that retains the vessel structure.  Since there are no human cells, the HAV  doesn’t cause any immune responses in the patient.

Humacyte HAV

This report described the early phase clinical trials.   That means safety was the main issue.  Checking for mechanical failure, rupture, bleeding, immune responses.  And, from that point of view, the tests in 60 patients (6 centers in the US and Poland) yielded stellar results.

The tests also examined the graft functionality.  They checked the blood flow rates achievable, how the graft responded to multiple needle punctures, etc.  With blood flow rates over 1 L/min, histological evidence of cell migration to repair the graft after needle puncture, the results were outstanding. Only one graft became infected over the course of the 16 month regimen.

This means phase 3 trials can proceed.  This phase is a randomized comparison against standard grafts made of PTFE (polytetrafluorethylene).

Looks like Humacyte is going to be offering a product within a few years.  One that will clearly improve the ability of dialysis patients to undergo dialysis.

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