lactoferrin and nimesulide

Three COX-2-specific non-steroidal anti-inflammatory drugs (NSAIDs), etoricoxib, parecoxib, and nimesulide are widely prescribed against inflammatory conditions. However, their long term administration leads to severe conditions of cardiovascular complications and gastric ulceration. In order to minimize these side effects, C-terminal half (C-lobe) of colostrum protein lactoferrin has been indicated to be useful if co-administered with NSAIDs. Lactoferrin is an 80kDa glycoprotein with two similar halves designated as N- and C-lobes. Since NSAID-binding site is located in the C-terminal half of lactoferrin, C-lobe was prepared from lactoferrin by limited proteolysis using proteinase K. The incubation of lactoferrin with serine proteases for extended periods showed that N-lobe was completely digested but C-lobe was resistant for more than 72h indicating its long half life in the animal gut. The solution studies have shown that COX-2-specific NSAIDs bind to C-lobe with binding constants ranging from 10(-4) to 10(-5)M showing significant affinities for sequestering these compounds. In order to understand the mode of binding and sequestering properties, the complexes of C-lobe with all these three compounds, etoricoxib, parecoxib, and nimesulide were prepared and the structures of their complexes with C-lobe were determined at 2.2, 2.9, and 2.7A resolutions, respectively. The analysis of the structures of complexes of C-lobe with NSAIDs clearly show that all the three compounds bind firmly at the same ligand-binding site in the C-lobe revealing the details of the interactions between C-lobe and NSAIDs. The mode of binding of COX-2-specific NSAIDs to C-lobe is similar to that of the binding of COX-2 non-specific NSAIDs to C-lobe.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Binding Sites; Cattle; Crystallography, X-Ray; Cyclooxygenase 2 Inhibitors; Etoricoxib; In Vitro Techniques; Isoxazoles; Lactoferrin; Models, Molecular; Peptide Fragments; Protein Binding; Protein Conformation; Pyridines; Sulfonamides; Sulfones

The superoxide (O2) production by phagocytes (neutrophils plus monocytes) and the lactoferrin release by neutrophils were measured in normal volunteers before and after the oral administration of the anti-inflammatory drug nimesulide. The chemotactic factor N-formylmethionyl-leucyl-phenylalanine (FMLP) and opsonized zymosan particles (OPZ) were used as activating stimuli. The oral administration of nimesulide lowered the phagocyte ability to generate O2- in response to both FMLP (percent inhibition = 67.62) and OPZ (percent inhibition = 36.75). The lactoferrin release by neutrophils was unaffected, proving that the drug does not affect the exocytosis of specific granules. The results provide direct evidence that the oral administration of nimesulide efficiently reduces the oxidative potential of phagocytes, particularly neutrophils, without interfering with mechanisms related to exocytosis of specific granules and involved in the amplification of the cell responses to inflammatory mediators.

Topics: Administration, Oral; Adult; Anti-Inflammatory Agents, Non-Steroidal; Humans; Lactoferrin; Monocytes; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Opsonin Proteins; Phagocytes; Sulfonamides; Superoxides; Zymosan