Like therapeutic plasma exchange, other forms of extracorporeal therapies — including other forms of apheresis and hemodialysis — are now being used to help not only people, but also our beloved pets. And, just as in human medicine, these modalities have evolved over time and continue to gain traction for use in veterinary medicine. We’re excited to share here an interview with one of the pioneers in the field — Dr. Larry Cowgill, Professor Emeritus, Medicine & Epidemiology, at the University of California, Davis School of Veterinary Medicine.

Access Point: Thank you for taking the time to share some of your experiences around the use of hemodialysis and apheresis in veterinary care. I believe you first got involved with these therapies while doing your residency at the University of Pennsylvania. Can you tell us more of the story?

Cowgill: It was around 1971 or ’72, and hemodialysis was in its infancy. One of my mentors reached out to me and said, “Larry, I'm going to send you down to the medical school to learn how to do this dialysis stuff in veterinary medicine.” So that's what I did during my residency, and I brought that with me when I came back to UC Davis in 1976. I set up a unit, [and] we started doing dialysis on dogs. We established the first clinical hemodialysis program in the world about 1990.

Access Point: How were you able to justify or fund the purchase of two machines for veterinary dialysis?

Cowgill: We had a very important benefactor that ran a no-kill dog shelter. One of his favorite dogs had kidney failure, and he wanted to do a transplant for the dog. I said, “We're not going to be able to transplant your dog, but I've been thinking about establishing chronic dialysis for dogs.”

Before that, we were mostly doing acute kidney failure. He said, “That sounds interesting. Send me a proposal overnight for what you need. Our board is meeting tomorrow, and I'm chairman of the board.” 

We just had an old, donated [dialysis] machine, so I went home that night, and I made a proposal for about $50,000. Two days later I got a check for $50,000. So, then we bought some real state-of-the-art equipment. And that's what really put extracorporeal therapies on the map. [Later] we got our first apheresis system.

Access Point: From those early days until now, how are you helping hemodialysis and apheresis become standard treatments in veterinary medicine?

Cowgill: We started a training program in 1993, but I could not market hemodialysis for about 30 years. There were four or five [veterinary hemodialysis] centers in the world at that time, but there just seemed to be no interest. In the early part of the 21st century it started to catch hold a little bit, and in 2014 we established a hemodialysis academy. This is a very extensive, one-year online training program available to people all over the world to learn the principles of extracorporeal therapies — hemodialysis, hemoperfusion, therapeutic plasma exchange, cytapheresis, and peritoneal dialysis. And we started doing apheresis in 2008.

We're in our fifth iteration. It's over 180 contact hours of training, and our current program has over 200 trainees [from] 32 countries. That's what really has started to establish extracorporeal therapies in veterinary medicine: People now have the training.

What you also need to create the market is to validate the indications, and that requires that you show that modality. We have a committee that's being formulated to make the equivalent of the ASFA [American Society for Apheresis] guidelines for veterinary medicine to create a best practices guideline for apheresis and veterinary medicine.

Access Point: What are the primary uses for apheresis in animals right now?


Cowgill: We were first using [plasma exchange] primarily for intoxications. We deal with a lot of intoxications in veterinary medicine and a lot of highly protein-bound toxins. You can't treat those with dialysis, and plasma exchange became the only option that we had to manage those. That was one of the big attractions for critical care.

The one that probably gets more traction is an immune-mediated red cell destruction we call autoimmune hemolytic anemia. In veterinary medicine it's a very common, very devastating disease with a 50% or 60% mortality rate. Over the last few years, we've been doing a case-controlled study with plasma exchange, and we get an over 93% survival rate versus 50% survival rate with medical therapy.

We also have a lot of immune-mediated polyarthritis. It also works really well for immune-mediated thrombocytopenia. But that's often an easier disease to treat with either steroids or immunoglobulins. And it can work for some of the really severe immune-mediated diseases that we deal with.

Access Point: What is the most common type of animal you treat with therapeutic apheresis — and what are some of the most unusual?

Cowgill: Mostly dogs. I think in our program we haven't done a cat yet. The indications aren't as big for cats as they are for dogs. But other programs have done cats.

We did a 600-kilogram (1,322-pound) horse once — very unusual. We went into it knowing that it was a chronic neurologic disease, an equivalent of Guillain Barré. We didn't have any expectation that we would make a big dent in that disease, but the client wanted to go and the clinician that was managing the horse wanted to go. It took 8 hours to do, but it was technically very, very effective.

Access Point: What are the biggest challenges with these procedures in veterinary medicine? 


Cowgill: With the horse, the blood flow rate was a bit limiting. We exchanged 56 liters of blood and gave 26 liters of plasma to that horse.

The smallest patient I've done is 1.2 kilos (2.6 pounds), so that's a challenge when you’ve got 140 milliliters extracorporeal volume. The other thing when we're doing a really small patient, we may have blood flow rates that are only 3 to 4 milliliters a minute. It's just slow — not necessarily slow in terms of the procedure, but it's slow waiting for that blood prime to get back to the patient.

Access Point: Are there other challenges beyond patient size?

Cowgill: Economics is a big piece. We use plasma as a replacement solution. We do have canine albumin, but it's not as readily available and so it's as expensive as the plasma. So the majority of our replacement solution for plasma exchanges is fresh frozen plasma. That's our major cost.

Access Point: Given the benefits versus the potential difficulties, what growth do you anticipate in the veterinary market for therapeutic apheresis?

Cowgill: I think you can absolutely expect exponential growth in plasma exchange. That's a given, and we keep expanding the indications. We're not doing CAR-T per se, but a group at Penn is doing a lot of CAR-T.

Another company has developed a method using adaptive T cells. We harvest the tumor, make a vaccine out of the tumor — mostly it's been for osteosarcoma, but other tumors are now being looked at. We vaccinate the dog, collect the vaccinal adaptive T cells, and they make antigen-specific adaptive killer T cells out of them. We infuse those back. That's been pretty successful, and that's one of the major uses for cytapheresis. In the United States, there are 15 or 16 groups that are participating in that program.

And there are two major centers that are pretty active in doing bone marrow transplantation. That's a slowly emerging indication in veterinary medicine, as well.

Access Point: That wraps up our interview today. Dr. Cowgill, thank you so much for sharing this experience and your insights with our readers.

About Larry Cowgill

Dr. Larry Cowgill recently retired after 48 years in veterinary medicine. He was a professor in the Department of Medicine and Epidemiology at the University of California Veterinary Medical Center, San Diego, and oversaw the companion animal hemodialysis units there and at the UC Davis Veterinary Medical Teaching Hospital. He is a pioneer in the application of hemodialysis in companion animals and remains a leading authority in the development of blood purification therapies for renal diseases in animals and people. Cowgill received his DVM degree from UC Davis and his PhD at the University of Pennsylvania School of Veterinary Medicine, where he completed an internship and a residency. 


The Spectra Optia^TM Apheresis System is not approved for use in animals. For detailed information on its indications for use and intended patient population, please refer to the Spectra Optia Operator's Manual.  

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