Urinary 3-hydroxypropyl mercapturic acid (3-HPMA) concentrations in dogs with acute spinal cord injury due to intervertebral disc herniation.

The aim of this study was to investigate urinary 3-hydroxypropyl mercapturic acid (3-HPMA), a metabolite of acrolein, as a novel biomarker in acute spinal cord injury (ASCI) due to intervertebral disc herniation in dogs. Urine from 10 client-owned dogs with ASCI collected at presentation and 10 control dogs was analyzed for 3-HPMA. The median urinary 3-HPMA concentration in ASCI dogs was significantly higher than in control dogs, but was not correlated with the severity of ASCI. The median urinary 3-HPMA concentration in intact dogs was higher than in neutered dogs. Higher urinary 3-HPMA concentrations in dogs after ASCI support a role for acrolein, a cytotoxic by-product of lipid peroxidation, in canine ASCI. Urinary 3-HPMA could be used as a biomarker in future clinical trials to measure the effect of therapeutic intervention of reducing acrolein after ASCI.

Concentrations of 15F2t isoprostane in urine of dogs with intervertebral disk disease.

OBJECTIVE: To measure 15F(2t) isoprostane concentrations in the urine of dogs undergoing ovariohysterectomy (OHE) and dogs undergoing surgery because of intervertebral disk disease (IVDD) and to assess relationships between urinary concentrations of 15F(2t) isoprostanes and neurologic score in dogs with IVDD. ANIMALS: 11 dogs undergoing OHE and 32 dogs with IVDD undergoing hemilaminectomy. PROCEDURES: Paired urine samples were obtained at induction of anesthesia and approximately 1 hour after OHE (controls) and were collected from dogs with IVDD at induction of anesthesia (28 samples) and approximately 1 hour after hemilaminectomy (31 samples); 26 paired urine samples were obtained from dogs with IVDD. Urinary isoprostane concentrations were measured by use of a commercial ELISA, and results were adjusted on the basis of urinary creatinine concentrations. Differences in the mean isoprostane-to-creatinine ratio were analyzed. Neurologic score was determined in dogs with IVDD by use of the modified Frankel scoring system. RESULTS: Urinary isoprostane-to-creatinine ratios were significantly higher in dogs with IVDD than in control dogs before and after surgery. There was no significant difference between values before and after surgery for either group. There was a significant correlation of neurologic score and urinary isoprostane-to-creatinine ratio because dogs that had higher neurologic scores (ie, less severely affected) generally had higher isoprostane-to-creatinine ratios. CONCLUSIONS AND CLINICAL RELEVANCE: Urinary isoprostane-to-creatinine ratios were higher in dogs with IVDD before and after surgery. Analysis of these data suggests that dogs with IVDD are in a state of oxidative stress and that preemptive treatment with antioxidants warrants further investigation.

Mechanism of action of intradiscal chymopapain in the treatment of sciatica: a clinical, biochemical, and radiological study.

Seventeen patients with intractable sciatica due to prolapse of a lumbar disc, treated by intradiscal injection of chymopapain (chemonucleolysis) were studied. Analysis of serial 24 hour urine collections showed a significant increase in urinary glycosaminoglycan after chemonucleolysis. This was not detected in four patients undergoing routine discography. Enzymic analysis of urinary glycosaminoglycan after chemonucleolysis suggested that the increase in levels was largely due to an increase in the amounts of chondroitin sulphate present, probably resulting from proteoglycan breakdown in the intervertebral disc. Eight of the patients treated by chemonucleolysis underwent serial computed tomography (CT). One month after the injection the only change seen was a loss of definition of the disc prolapse, which could be interpreted as a loss of turgidity in the disc as a result of proteoglycan breakdown by chymopapain. By six months the CT of those patients whose symptoms had improved showed that the degree of disc prolapse was usually less marked and the disc margin more clearly defined, suggesting that by this stage anatomical remodelling had occurred.