Mixed Results From Feline EPO Clinical Trial
The first clinical trial of recombinant feline erythropoietin (rfEPO) therapy in cats with nonregenerative anemia has produced generally good results – but some puzzling findings, too.
Of the 26 cats in the study, which was reported in the American Journal of Veterinary Research (Vol. 65, No. 10), 19 were anemic as a result of chronic kidney disease. The remaining seven had red-cell aplasia as a result of earlier treatment with recombinant human EPO. (In such cases, red-cell aplasia is known to develop as a result of the feline immune response to human EPO, which the immune system recognizes as foreign.)
Most of the cats in the study initially regained the ability to make enough red blood cells in their bone marrow after treatment with rfEPO. But the Cornell researchers were surprised to discover, part-way through the trial, that eight of the cats had again developed anemia. This anemia apparently also resulted from red-cell aplasia, but this time the cause appeared to be an unexpected immune reaction against feline, not human, EPO.
Manufactured EPO is called recombinant because it is produced by means of genetic engineering. Recombinant canine EPO, which was also developed by the Cornell researchers, had proven more successful in a clinical trial of anemic dogs with chronic kidney disease, and the researchers hoped the feline version would be similarly helpful to cats with anemia due to kidney disease, cancer or other diseases.
The researchers remain hopeful that a safe, therapeutic option will someday be available for the management of EPO-dependent nonregenerative anemia in cats. While safety issues make it clear that more research is needed, they believe that their findings from this first clinical trial will enable scientists to make more informed decisions on how best to proceed in the future.
Feeling Cats Pain
When to give analgesic medication to ease cats pain has always been a puzzle. Theyre a stoic bunch, those cats – not whiners like dogs tend to be.
As a result, says an article in the Journal of Feline Medicine and Surgery (Vol. 6, No. 5), cats tend to be under treated for pain and remain the poor relatives of the dog. While dogs are frequently treated for the pain of arthritis, cats rarely are. Yet X-ray studies show evidence of arthritis in up to 90 percent of geriatric cats.
Not that vets havent tried to feel cats pain. Repeated attempts to find physiological signs – changes in heart rate, body temperature, respiratory rates, plasma cortisol and beta-endorphins – have failed to tell when cats are hurting.
Better to look for behavioral signs of pain, according to the journal authors. If cats suddenly become tense and distanced from their environment, if they are depressed, immobile and silent – or instead become manic, aggressive and growling – those are signs of pain, they suggest.
Cats human companions should watch for signs of pain at home, too, they say. Lameness may be hard to spot, but if a cat is having trouble jumping up, or if it grooms less or soils outside the litter box, that could be a synonym for ouch.
Next time Toonces, the Cat Who Could Drive a Car, is asked to take a breath test, it wont be for alcohol. As reported in the same journal, English and Belgian researchers have figured out how to collect exhaled breath condensate from cats and test it for respiratory disease.
Cats hate to breathe into masks, so the researchers built a clear, plastic box with one tube bringing in fresh air and another collecting exhaled air. Their spectrographic analysis of exhaled air successfully detected hydrogen peroxide – an early sign of asthma or respiratory distress syndrome in humans. Although its still too early to tell, the researchers believe this technique may eventually prove useful in diagnosing lower airway disease in cats.