Chemical in blood may explain susceptibility to bl...( COLUMBUS Ohio A marker in the blood...)

COLUMBUS, Ohio A marker in the blood of both cats and humans that was identified in a recent study might signal both species' susceptibility for a painful bladder disorder called interstitial cystitis, a condition that is often difficult to diagnose.

Follow-up studies of the chemicals that appeared in blood samples suggest that the way tryptophan, an essential amino acid, is processed in cats and humans with interstitial cystitis ultimately could affect the way signals are transmitted in the brain. The results, while preliminary, suggest that the disease is not just a malfunction of the bladder, but might instead have origins in the central nervous system, researchers say.

Symptoms of interstitial cystitis, known as IC, include recurring discomfort or pain in the bladder and pelvis, and often both an urgent and frequent need to urinate. A diagnosis typically follows tests to rule out other diseases, such as infections or cancer. No diagnostic test currently exists for IC, and the cause is unknown. Treatments range from oral medications to exercise for humans, and maintaining a safe environment for cats.

"What we know now is that this testing method is very sensitive and specific for the disorder in both humans and domestic cats. So far it hasn't missed one diagnosis," said Tony Buffington, senior author of the study and professor of veterinary clinical sciences at Ohio State University.

The research is published in the current issue of the journal Analyst.

Buffington and colleagues collected samples from cats with feline interstitial cystitis, healthy cats and cats with other diseases, as well as samples from humans with the painful bladder syndrome, healthy humans and humans with other urological illnesses.

He and colleagues used infrared microspectroscopy to tell the difference between blood samples indicating the presence or lack of disease based on the samples' molecular profiles. Infrared spectr
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