Dihydroouabain-like factor and diagnostic & therapeutic compositions and methods

Abstract

A novel mammalian dihydroouabain-like factor is disclosed which substantially fails to cross-react with mammalian ouabain-like factor (OLF) for binding to anti-OLF antibody, but cross-reacts with plant-related dihydroouabain (dho) for binding to anti-dho antibody, has maximal u.v. absorbance at 196 nm, has a non-peptidic, non-lipidic chemical structure and a fully hydrogenated lactone ring, has a concentration-dependent Na + ,K + -ATPase (sodium pump) catalytic inhibitory activity which is 10-fold lower than OLF and 3-fold higher than plant-related dihydroouabain, and a high pressure liquid chromatography elution time about the same as dho. This factor is useful for therapy for congestive heart failure. An antibody and antibody fragments having affinity for mammalian Dh-OLF but not for OLF, and diagnostic and therapeutic methods comprise the antibody and means for quantifying the antibody and are useful for treating a condition caused by high level of OLF or Dh-OLF. Two isomers of plant-related dihydroouabain have been isolated. These compositions and methods are suitable for characterizing a variety of diseases and conditions associated with reduced sodium pump activity.

1 - 9 . (canceled)  
     
     
         10 . A method of prophylactically or therapeutically treating a condition associated with higher than normal sodium pump activity, comprising administering to a subject in need of the treatment an effective amount of a pharmaceutical composition comprising a purified mammalian dihydroouabain-like factor (Dh-OLF) having binding reactivity with antibody raised against dihydroouabain (dho), and a pharmaceutically or veterinarily acceptable carrier.  
     
     
         11 . The method of  claim 10  wherein the composition is administered parenterally.  
     
     
         12 . The method of  claim 10  wherein the composition is administered orally.  
     
     
         13 . The method of  claim 10  wherein the composition is administered in an amount of about 1 μg/kg to about 1.5 mg/kg body weight.  
     
     
         14 . The method of  claim 11  wherein the subject is human.  
     
     
         15 . The method of  claim 11  wherein the disease or condition is heart disease, and the composition is administered in an effective amount.  
     
     
         16 . The method of  claim 15  wherein the heart disease is congestive heart failure.  
     
     
         17 . The method of  claim 11  where in the disease or condition is hypertension, and the composition is administered in an effective amount.  
     
     
         18 . The method of  claim 17  wherein the hypertension is selected from the group consisting of essential hypertension, thyroidism-induced hypertension, and pregnancy-induced or pregnancy-associated hypertension.  
     
     
         19 . The method of  claim 10  wherein the disease or condition is cataracts, and the composition is administered in an effective amount.  
     
     
         20 . The method of  claim 10  wherein the disease or condition is Alzheimer's disease, and the composition is administered in an effective amount.  
     
     
         21 . A binding agent having affinity for a purified mammalian dihydroouabain-like factor (Dh-OLF) having binding reactivity with antibody raised against dihydroouabain (dho).  
     
     
         22 . The binding agent of  claim 21  selected from the group consisting of polyclonal antibodies, monoclonal antibodies, F v  fragments and aptomers.  
     
     
         23 . A pharmaceutic composition comprising the binding agent of  claim 22  and a pharmaceutically or veterinarily acceptable carrier.  
     
     
         24 . A method of prophylactically or therapeutically treating a condition associated with higher than normal OLF or DhOLF levels comprising administering to a subject in need of the treatment an effective amount of the composition of  claim 23 .  
     
     
         25 . The method of  claim 24 , wherein the antibody is administered in an amount of about 0.1 to about 1000 μmol/kg body weight.  
     
     
         26 . The method of  claim 24  wherein the subject is human.  
     
     
         27 . A quantitative method of detecting Dh-OLF in an animal sample, comprising 
 obtaining a test sample suspected of comprising Dh-OLF analyte;    contacting the test sample with a solid substrate-bound first binding agent having specificity for Dh-OLF or for dho isomer mixture but not for OLF, under conditions effective for said first binding agent to bind any analyte present in the sample and form binding agent-analyte complex(es);    contacting the substrate-bound first binding agent-analyte complex(es) with a labeled second binding agent specific to the first binding agent, under conditions effective to bind to any substrate-bound analyte-first agent to form a solid substrate-bound analyte-anti-Dh-OLF binding agent-second-binding agent or analyte-anti-dho binding agent-second binding agent labeled complex(es);    detecting the amount of solid substrate-bound label; and    comparing that amount of complex(es) to the amount of complex(es) obtained for a known amount of a standard Dh-OLF or dho under the same or similar conditions.    
     
     
         28 . The method of  claim 26  wherein the binding agent comprises anti-Dh-OLF, anti-dho antibody, fragments or aptomers.  
     
     
         29 . The method of  claim 26  wherein the subject is human.  
     
     
         30 . A quantitative method of detecting Dh-OLF in an animal sample comprising isolating Dh-OLF by HPLC and comparing the height of the peak characteristic of Dh-OLF to that of a known amount of dho-B separated in the same or similar manner.  
     
     
         31 . The method of  claim 30  wherein the sample is taken from a human.  
     
     
         32 . A purified plant-related dho isomer.  
     
     
         33 . The isomer of  claim 32  that is dho-A.  
     
     
         34 . The isomer of  claim 32  that is dho-B.