Response of antimicrobial peptides from porcine neutrophils to pentoxifylline and antigens from Gram negative and Gram positive bacteria

Neutrophils, the main component of the defense against invading organisms have also been implicated in tissue damage in numerous inflammatory conditions. Neutrophil products can degrade the extracellular matrix and when excessively released are thought to cause some disorders. As it is known, pentoxifylline (PTX) can suppress a range of neutrophil responses. Cathelicidins are components of the early host defenses against infection, however, in most cases cleavage with elastase is necessary to obtain active forms. Thus, the aim of our study was to assess the usage of PTX as a factor which could inhibit some neutrophil functions, and to assess if PTX can lead to the impairment of the release from these cells active cathelicidins. For these purposes we determined neutrophil activity as well as expression of cathelicidins from porcine neutrophils in cultures under the influence of PTX. PTX exerted an inhibitory effect on elastase and MPO release from neutrophils. At lower concentrations of PTX, ALP release was inhibited both in cultures stimulated with PTX+fMLP and with PTX+LPS. Inhibition of superoxide generation was insignificant, whereas a decrease of NO production was noted. The MALDI TOF analysis revealed that in all cultures stimulated with PTX+fLMP and PTX+LPS there was no inhibition of the release of cathelicidins in comparison with cultures stimulated only with fMLP and only with LPS. Our study proved that although PTX in porcine neutrophils is able to suppress many neutrophil functions, the expression of cathelicidins is maintained.

Proliferative and oxidative response of hepatocytes (Hep) and hepatic stellate cells (HSC) isolated from rats exposed to ketogenic diet

Ketogenic diet (KD) is considered in the context of its anti-epileptic effects, but its influence on liver dysfunction has not been elucidated yet. The study was aimed to investigate the activity of hepatocytes (Hep) and hepatic stellate cells (HSC) isolated from rats fed with KD, in respect of NO and superoxide generation by these cells as well as their proliferative activity in vitro. We also sought to characterize the plasma FFA profiles in control and ketogenic rats. Hep and HSC were isolated by the collagenase perfusion method and separated by the Percoll gradient centrifugation. After the 4th, 8th and 12th day of incubation, the media were collected for further analysis. NO generation increased within the time of incubation both in Hep and HSC isolated from KD-rats. In HSC group NO production raised significantly from 2.65 ± 0.07 μM/10(6) cells on 4th day of incubation to 5.49 ± 1.2 μM/10(6) cells on 12th day of incubation. In respect to O2⁻· generation experimental Hep and HSC provide considerably higher quantities of this free radical until 12th day of incubation (2.5 ± 0.07 and 3.2 ± 0.3 nM/10(6) cells, respectively). Although KD exerts anti-proliferative effect on hepatocytes, in respect to HSC it intensifies their proliferative activity. Furthermore, as we estimated on the basis of NO and O2⁻. generation both Hep and HSC exposed to KD are the source of free radicals.