Lack of enantiomeric influence on the brain cytoprotective effect of ibuprofen and flurbiprofen

Abstract

R(-) enantiomers of the 2-arylpropionic acid derivatives ibuprofen and flurbiprofen weakly inhibit cyclooxygenase (COX) activity. However, a possible cytoprotective effect has been proposed. The aim of the study is to investigate the possible mechanism of this effect. An in vitro hypoxia-reoxygenation model in rat brain slices was used (n=6 rats per group). After reoxygenation, we measured LDH efflux (neuronal death), brain prostaglandin E(2) (PGE(2)) concentration, interleukins (IL)-1β and 10, oxidative and nitrosative stress (lipid peroxides, glutathione, 3-nitrotyrosine, and nitrites/nitrates). Anti-COX activity was measured in human whole blood. Racemic, R(-), and S(+) enantiomers of ibuprofen and flurbiprofen were tested. All compounds had a cytoprotective effect with IC(50) values in the range of 10(-5) M. R(-) enantiomers did not significantly inhibit brain PGE(2). The concentration of IL-1β was reduced by 53.1% by the racemic form, 30.6% by the S(+) and 43.2% by the R(-) enantiomer of ibuprofen. The IL-10 concentration increased significantly only with S(+)-flurbiprofen (33.1%) and R(-)-flurbiprofen (26.1%). Lipid peroxidation was significantly reduced by all three forms of flurbiprofen. Nitrite + nitrate concentrations were reduced by racemic, S(+), and R(-)-flurbiprofen. Peroxynitrite formation (3-nitrotyrosine) was significantly reduced by racemic and S(+)-ibuprofen. COX inhibition is not the main mechanism of cytoprotection for these compounds. Their influence on inflammatory mediators and oxidative and nitrosative stress could account for the potential cytoprotective effect of R(-) enantiomers.

R‐flurbiprofen attenuates experimental autoimmune encephalomyelitis in mice

“…Efflux inhibition results in an attenuation of prostaglandin release (Geisslinger et al , ) but facilitation of intracellular steroid‐receptor‐mediated effects with an induction of CTLA 4 and IL 10 and repression of NF ‐κB and AP ‐1 (Tegeder et al , ), important mechanisms which contribute to the estrogen‐receptor‐mediated protection in EAE models (Crawford et al , ; Khalaj et al , ; Kumar et al , ; Luna et al , ; Saijo et al , ; Wu et al , ). Blocking the efflux of glutathione will increase the intracellular glutathione pool and increase the antioxidative capacity, which may explain previously observed reductions of lipid peroxidation (Lopez‐Villodres et al , ), and prevention of mitochondrial calcium overload in stressed cells (Sanz‐Blasco et al , ) likely contributed by increasing chaperone activity and reduction of ER stress (Hosoi et al , ). Collectively, these effects favor the differentiation of regulatory and inflammation‐resolving T cells.…”

“…Efficacy was shown for clinical scores, microglial activation, macrophage and T-cell invasion and gene regulation by in vivo imaging, histology, quantitative FACS analyses and microarray gene expression analysis. The mechanisms likely involve a combination of the previously described molecular effects of R-flurbiprofen (illustrated in Fig 13 ), including modulation of endocannabinoids (Bishay et al , 2010 ; Duggan et al , 2011 ; Holt & Fowler, 2003 ), activation of PPARs (Bernardo et al , 2005 ; Bishay et al , 2010 ) and retinoid X receptor (RXR) (You et al , 2009 ), inhibition of NF-κB and AP1 (Tegeder et al , 2001 ) and of acid sensitive ion channels (ASIC1) (Mishra et al , 2010 ; Voilley et al , 2001 ) and propagation of antioxidative capacity (Lopez-Villodres et al , 2011 ; Sanz-Blasco et al , 2008 ). PPAR activators and inhibitors of NF-κB are currently being evaluated as potential therapeutics for MS (Dasgupta et al , 2007 ; Dunn et al , 2010 ; Klotz et al , 2005 ) mainly because they reduce the inflammatory component of the disease.…”

“…Consequently, long‐term treatment with R‐flurbiprofen of amyloid peptide‐overexpressing mice, before appearance of cognitive dysfunction, resulted in a reduction of brain plaque formation, Aβ42 deposition and improvement of spatial learning behavior (Kukar et al , ), and prevention of mitochondrial calcium overload evoked by Aβ‐oligomers (Sanz‐Blasco et al , ). Under oxidative stress conditions, it reduced nitrite/nitrate levels and lipid peroxidation in the brain and enhanced the release of the anti‐inflammatory interleukin‐10 (Lopez‐Villodres et al , , ). The beneficial effects of the drug may be partly lost in the aging brain (Bishay et al , ), and ultimately, its development was discontinued for Alzheimer's disease because efficacy in clinical phase III trials was insufficient (Green et al , ).…”

R-flurbiprofen attenuates experimental autoimmune encephalomyelitis in mice

“…Efflux inhibition results in an attenuation of prostaglandin release but facilitation of intracellular steroid-receptor-mediated effects with an induction of CTLA4 and IL10 and repression of NF-jB and AP-1 (Tegeder et al, 2001), important mechanisms which contribute to the estrogen-receptor-mediated protection in EAE models (Crawford et al, 2010;Khalaj et al, 2013;Kumar et al, 2013;Luna et al, 2010;Saijo et al, 2011;Wu et al, 2013). Blocking the efflux of glutathione will increase the intracellular glutathione pool and increase the antioxidative capacity, which may explain previously observed reductions of lipid peroxidation (Lopez-Villodres et al, 2011), and prevention of mitochondrial calcium overload in stressed cells (Sanz-Blasco et al, 2008) likely contributed by increasing chaperone activity and reduction of ER stress (Hosoi et al, 2014). Collectively, these effects favor the differentiation of regulatory and inflammation-resolving T cells.…”

“…Consequently, long-term treatment with R-flurbiprofen of amyloid peptide-overexpressing mice, before appearance of cognitive dysfunction, resulted in a reduction of brain plaque formation, Ab42 deposition and improvement of spatial learning behavior (Kukar et al, 2007), and prevention of mitochondrial calcium overload evoked by Ab-oligomers (Sanz-Blasco et al, 2008). Under oxidative stress conditions, it reduced nitrite/nitrate levels and lipid peroxidation in the brain and enhanced the release of the anti-inflammatory interleukin-10 (Lopez- Villodres et al, 2011Villodres et al, , 2012. The beneficial effects of the drug may be partly lost in the aging brain (Bishay et al, 2013), and ultimately, its development was discontinued for Alzheimer's disease because efficacy in clinical phase III trials was insufficient (Green et al, 2009).…”