The invention is in the field of molecular medicine. It provides antagonistic compounds for frizzled 1 and/or frizzled-2 receptors, which may be useful in molecular imaging of the wound healing process after myocardial infarction and in therapeutic intervention into wound healing after remodeling of the heart, thereby ameliorating the consequences of myocardial infarction. The invention provides a method for antagonizing frizzled-1 or frizzled-2 receptors, wherein the receptor is contacted with a composition comprising a linear fragment of Wnt3(a) or Wnt5a or a functional analogue thereof, which comprises at least one cysteine residue, one threonine residue, one aspartic acid residue and one glycine residue.