Abstract: The present invention is directed to use of an agent which is able to prevent pathological overexpression of TGF-&bgr; gene in vivo for the preparation of a medicament for the treatment of disorders connected with AP-1 mediated TGF-&bgr; gene expression, except use of sulodexide, low molecular weight heparin derivatives obtained by chemical or enzymatic depolymerization, chemically modified heparin derivatives and low molecular weight dermatan sulfates obtained by chemical or enzymatic depolymerization for the treatment of diabetic nephropathy. Further, the invention provides convenient, fast in vitro methods to assess the value of agents useful for the said disorders.