Assays for detection of glycosaminoglycans

Abstract

Disclosed herein are novel methods, assays and kits useful for the diagnosis and monitoring of subjects with mucopolysaccharidoses (MPS), The methods, assays and kits are particularly useful for detecting the presence of one or more glycosaminoglycans which correlate to MPS and its severity in a variety of biological samples.

1 - 22 . (canceled) 
     
     
         23 . A method of determining the efficacy of one or more therapeutic agents or regimens for treatment of mucopolysaccharidosis (MPS) comprising determining the concentration of one or more glycosaminoglycans in a first biological sample obtained from an individual prior to administration of one or more therapeutic agents or regimens to said individual, determining the concentration of said glycosaminoglycans in a second biological sample obtained from said individual after administration of one or more therapeutic agents or regimens to said individual, wherein if the concentration of said glycosaminoglycans in said second biological sample is lower than the concentration in said first biological sample the one or more therapeutic agents or regimens are efficacious for treatment of MPS, and wherein determining the concentration of one or more glycosaminoglycans in the first and second biological samples is performed by a method comprising (a) combining a serine protease, a labeled substrate for said serine protease, an inhibitor of said serine protease, and the first or second biological sample under conditions and for a time suitable for cleavage of the labeled substrate by the serine protease to produce a detectable signal, (b) detecting the detectable signal, and (c) comparing the amount of detectable signal with a standard to determine the concentration of said one or more glycosaminoglycans in said sample, wherein the serine protease is a serine protease of the clotting cascade, wherein said inhibitor of said serine protease is selected from the group consisting of heparin cofactor II and antithrombin III, and wherein said one or more glycosaminoglycans are selected from the group consisting of dermatan sulfate (DS) and heparan sulfate (HS). 
     
     
         24 . The method of  claim 23 , wherein said one or more therapeutic agents or regimens are selected from the group consisting of enzyme replacement therapies, bone marrow transplantation, and combinations thereof. 
     
     
         25 . The method of  claim 23 , wherein said one or more therapeutic agents are selected from the group consisting of iduronate sulfatase, idursulfase, alpha-L-iduronidase, heparin sulfamidase, N-acetylglucosaminidase, N-acetylglucosamine 6-sulfatase, N-acetylgalactosamine-4-sulfatase and beta-glucoronidase. 
     
     
         26 . A method according to  claim 23  wherein the serine protease is selected from the group consisting of the serine proteases shown in  FIG. 7  and  FIG. 8 . 
     
     
         27 . A method according to  claim 23  wherein the labeled substrate is a chromogenic or fluorogenic substrate. 
     
     
         28 . A method according to  claim 23  wherein the serine protease is thrombin and the labeled substrate is a chromogenic thrombin substrate. 
     
     
         29 . A method according to  claim 23  wherein detecting the detectable signal is performed by spectrophotometric detection. 
     
     
         30 . A method according to  claim 29  wherein the spectrophotometric detection is performed at 405 nm. 
     
     
         31 . A method according to  claim 23  wherein the first and second biological samples are selected from the group consisting of urine, serum, cerebrospinal fluid, and saliva. 
     
     
         32 . A method according to  claim 23  wherein the standard is a curve which calibrates spectrophotometric absorbance with glycosaminoglycan concentration. 
     
     
         33 . A method according to  claim 23 , wherein the MPS is selected from the group consisting of MPS I, MPS II, MPS IIIA, MPS IIIB, MPS IIIC, MPS HID, MPS IVA, MPS IVB, MPS VI, MPS VII and MPS IX. 
     
     
         34 - 35 . (canceled)