Inhibition by soya isoflavones of human polymorphonuclear leukocyte function: Possible relevance for the beneficial effects of soya intake

Serenella Rotondo, Katarzyna Krauze-brzósko, Stefano Manarini, Nicola Martelli, Romina Pecce, Virgilio Evangelista, Maria Benedetta Donati, Chiara Cerletti

Research output: Contribution to journalArticlepeer-review

Abstract

Lower CVD incidence is reported in Asian populations consuming soya-containing food. As polymorphonuclear leukocytes (PMN) are involved in the risk of CVD, we investigated the modulatory effect of soya isoflavones on several PMN functions and their molecular mechanisms in vitro. PMN, isolated from blood from healthy subjects, were tested upon activation with 1 μm- n-formyl-methyl-leucyl-phenylalanine (fMLP) for superoxide anion production (ferric cytochrome c reduction) and released elastase (chromogenic test). PMN homotypic aggregates stimulated by fMLP or P-selectin in dynamic conditions were detected by optical microscopy. PMN, mixed with thrombin-activated, washed platelets, formed cell aggregates, measured by flow cytometry. Phosphorylation of Pyk2, a focal adhesion kinase, was studied by immunoprecipitation and immunoblotting with specific antibodies. Genistein, daidzein and equol inhibited superoxide anion production (IC50 0.25 (sem 0.1), 21.0 (sem 4.2) and 13.0 (sem2.8) μm, respectively); the release of elastase was prevented by genistein (IC50 63 (sem 17) μm). PMN homotypic aggregates, stimulated by fMLP, were significantly reduced (24 (sem 12) and 51 (sem 14)% of control) by 100μm genistein and equol. P-selectin-induced aggregates were reduced to 19 (sem 6), 44 (sem 10) and 28 (sem 9)% of control by 100μm genistein, daidzein and equol, respectively. Genistein, daidzein and equol also significantly reduced mixed platelet-PMN aggregates (IC50 4.0 (sem 0.9), 57 (sem 6) and 66 (sem 23) μm, respectively). In PMN challenged by fMLP or P-selectin, activation of Pyk2 was prevented by isoflavones. The cardioprotective effect of soya-containing food might be linked to reduction of PMN activation and PMN-platelet interaction, novel targets for the biological effects of soya isoflavones.

Original languageEnglish
Pages (from-to)240-247
Number of pages8
JournalBritish Journal of Nutrition
Volume99
Issue number2
DOIs
Publication statusPublished - Feb 2008

Keywords

  • Polymorphonuclear leukocytes
  • Soya isoflavones

ASJC Scopus subject areas

  • Medicine (miscellaneous)

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