The isolation and characterization of glycosaminoglycans in normal human serum

Imaging of homeostatic, neoplastic, and injured tissues by HA-based probes

An increase in hyaluronan (HA) synthesis, cellular uptake, and metabolism occurs during the remodeling of tissue microenvironments following injury and during disease processes such as cancer. We hypothesized that multimodality HA-based probes selectively target and detectably accumulate at sites of high HA metabolism, thus providing a flexible imaging strategy for monitoring disease and repair processes. Kinetic analyses confirmed favorable available serum levels of the probe following intravenous (i.v.) or subcutaneous (s.c.) injection. Nuclear (technetium-HA, (99m)Tc-HA, and iodine-HA, (125)I-HA), optical (fluorescent Texas Red-HA, TR-HA), and magnetic resonance (gadolinium-HA, Gd-HA) probes imaged liver ((99m)Tc-HA), breast cancer cells/xenografts (TR-HA, Gd-HA), and vascular injury ((125)I-HA, TR-HA). Targeting of HA probes to these sites appeared to result from selective HA receptor-dependent localization. Our results suggest that HA-based probes, which do not require polysaccharide backbone modification to achieve favorable half-life and distribution, can detect elevated HA metabolism in homeostatic, injured, and diseased tissues.

Analysis of glycosaminoglycans in human serum after oral administration of chondroitin sulfate

Chondroitin sulfate was administered orally to six healthy volunteers, six patients with rheumatoid arthritis and six patients with osteoarthritis. Blood was collected at intervals before and after treatment and the glycosaminoglycan concentration was analyzed in serum using a sensitive assay based on the metachromatic reaction with 1,9-dimethylmethylene blue. The glycosaminoglycan concentration in serum before and after ingestion of chondroitin sulfate was statistically unchanged in all of the subjects studied. We suggest that chondroprotection by orally administered chondroitin sulfate is a biologically and pharmacologically unfounded theory. Any possible benefit to osteoarthritic patients after ingestion of chondroitin sulfate should be sought at the gastrointestinal rather than at the plasmatic or articular cartilage level.

Human serum and urine glycosaminoglycans in health and in patients with chronic renal failure

Quantitation of uronic acid precipitable by cetylpyridinium chloride (CPC) and electrophoretic separation of glycosaminoglycans were performed on sera from patients with chronic renal failure and compared to normal controls. Serum CPC-precipitable uronic acid (CpUA) levels in patients with renal failure were significantly higher (mean 13.7 mg/L, range 7.1-23.6 mg/L) than normal controls (mean 9.6 mg/L, range 5.1-13.9 mg/L) due to increased concentrations of low sulphated chondroitin sulphate. A positive correlation between serum CpUA and creatinine was found in renal failure patients. Urine CpUA excretion was raised in renal failure patients compared to normal controls with an increased excretion of chondroitin sulphate (Ch-S) of reduced electrophoretic mobility. Heparan sulphate (HS), a major glycosaminoglycan in normal urine, was absent from the urine of these patients. The possible origin of urine glycosaminoglycans and the role of the kidney in glycosaminoglycan metabolism are discussed.