N-acetylcysteine prevents spatial memory impairment induced by chronic early postnatal glutaric acid and lipopolysaccharide in rat pups.

BACKGROUND AND AIMS:Glutaric aciduria type I (GA-I) is characterized by accumulation of glutaric acid (GA) and neurological symptoms, such as cognitive impairment. Although this disease is related to oxidative stress and inflammation, it is not known whether these processes facilitate the memory impairment. Our objective was to investigate the performance of rat pups chronically injected with GA and lipopolysaccharide (LPS) in spatial memory test, antioxidant defenses, cytokines levels, Na+, K+-ATPase activity, and hippocampal volume. We also evaluated the effect of N-acetylcysteine (NAC) on theses markers. METHODS:Rat pups were injected with GA (5 umol g of body weight-1, subcutaneously; twice per day; from 5th to 28th day of life), and were supplemented with NAC (150 mg/kg/day; intragastric gavage; for the same period). LPS (2 mg/kg; E.coli 055 B5) or vehicle (saline 0.9%) was injected intraperitoneally, once per day, from 25th to 28th day of life. Oxidative stress and inflammatory biomarkers as well as hippocampal volume were assessed. RESULTS:GA caused spatial learning deficit in the Barnes maze and LPS potentiated this effect. GA and LPS increased TNF-α and IL-1β levels. The co-administration of these compounds potentiated the increase of IL-1β levels but not TNF-α levels in the hippocampus. GA and LPS increased TBARS (thiobarbituric acid-reactive substance) content, reduced antioxidant defenses and inhibited Na+, K+-ATPase activity. GA and LPS co-administration did not have additive effect on oxidative stress markers and Na+, K+ pump. The hippocampal volume did not change after GA or LPS administration. NAC protected against impairment of spatial learning and increase of cytokines levels. NAC Also protected against inhibition of Na+,K+-ATPase activity and oxidative markers. CONCLUSIONS:These results suggest that inflammatory and oxidative markers may underlie at least in part of the neuropathology of GA-I in this model. Thus, NAC could represent a possible adjuvant therapy in treatment of children with GA-I

Effect of early postnatal chronic GA, NAC and LPS administration on hippocampal volume.

<p>Data represent means ± S.E.M. for n = 5-6 in each group. No significant differences between groups were detected.</p

Effect of early postnatal chronic GA, NAC and LPS administration on NPSH content, GSH level, CAT and SOD activities.

<p>NAC prevented the decrease of antioxidant defenses induced by GA and LPS.*P < 0.001 compared with saline treated group and ^#P< 0.001 compared with respective control group (Duncan’s multiple comparisons test). Data are presented as means ± S.E.M. for n = 7 in each group.</p

NAC prevents the memory deficit induced by GA and LPS measured as escape latency of rat pups in the Barnes maze.

<p>*P < 0.05 compared with saline treated group, ^#P< 0.05 compared with respective control group and ^δP < 0.001 compared with GA-treated group (Duncan’s multiple comparisons test). Data are presented as means ± S.E.M. for n = 7-9 in each group. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078332#pone-0078332-g003" target="_blank">Figures 3B and 3C</a> show an amplification of the second day of test.</p

Effect of early postnatal chronic GA, NAC and LPS administration on TBARS content.

<p>NAC prevented the increase of TBARS content induced by GA and LPS. *P < 0.01 compared with saline treated group and ^#P< 0.05 compared with respective control group (Duncan’s multiple comparisons test). Data are presented as means ± S.E.M. for n = 7 in each group.</p

Effect of early postnatal chronic GA, NAC and LPS administration on cytokine levels on the second day of Barnes maze.

<p>NAC prevented the increase in TNF-α (A) and IL-1β (B) levels. *P < 0.001 compared with saline treated group, ^#P< 0.001 compared with the respective control group and ^δP < 0.05 compared with GA-treated group (Duncan’s multiple comparisons test). Data are presented as means ± S.E.M. for n = 6-7 in each group.</p

NAC prevented the decrease of α1 subunit activity of Na⁺,K⁺-ATPase enzyme.

<p>Effect of early postnatal chronic GA, NAC and LPS administration on Na⁺,K⁺-ATPase total activity (A); on α1 subunit activity of Na⁺,K⁺-ATPase enzyme (B); and on α2/3 subunit activity of Na⁺,K⁺-ATPase enzyme (C), on the second day of Barnes maze.*P < 0.001 compared with saline traded group and ^#P< 0.001 compared with respective control group (Student–Newman–Keuls test). Data are presented as means ± S.E.M. for n = 7-9 in each group.</p

Digitized images of dorsal hippocampus showing similarities in the volume of this region between the different experimental groups.

<p>Schematic drawing obtained from Paxinos and Watson's Atlas. </p

Effect of early postnatal chronic GA, NAC and LPS administration on physical development of animals.

<p>Data are presented as means ± S.E.M. for n = 8–9 in each group. No significant differences between groups were detected.</p

Improvement of ALT decay kinetics by all-oral HCV treatment: Role of NS5A inhibitors and differences with IFN-based regimens

BACKGROUND: Intracellular HCV-RNA reduction is a proposed mechanism of action of direct-acting antivirals (DAAs), alternative to hepatocytes elimination by pegylated-interferon plus ribavirin (PR). We modeled ALT and HCV-RNA kinetics in cirrhotic patients treated with currently-used all-DAA combinations to evaluate their mode of action and cytotoxicity compared with telaprevir (TVR)+PR. STUDY DESIGN: Mathematical modeling of ALT and HCV-RNA kinetics was performed in 111 HCV-1 cirrhotic patients, 81 treated with all-DAA regimens and 30 with TVR+PR. Kinetic-models and Cox-analysis were used to assess determinants of ALT-decay and normalization. RESULTS: HCV-RNA kinetics was biphasic, reflecting a mean effectiveness in blocking viral production >99.8%. The first-phase of viral-decline was faster in patients receiving NS5A-inhibitors compared to TVR+PR or sofosbuvir+simeprevir (p<0.001), reflecting higher efficacy in blocking assembly/secretion. The second-phase, noted δ and attributed to infected-cell loss, was faster in patients receiving TVR+PR or sofosbuvir+simeprevir compared to NS5A-inhibitors (0.27 vs 0.21 d-1, respectively, p = 0.0012). In contrast the rate of ALT-normalization, noted λ, was slower in patients receiving TVR+PR or sofosbuvir+simeprevir compared to NS5A-inhibitors (0.17 vs 0.27 d-1, respectively, p<0.001). There was no significant association between the second-phase of viral-decline and ALT normalization rate and, for a given level of viral reduction, ALT-normalization was more profound in patients receiving DAA, and NS5A in particular, than TVR+PR. CONCLUSIONS: Our data support a process of HCV-clearance by all-DAA regimens potentiated by NS5A-inhibitor, and less relying upon hepatocyte death than IFN-containing regimens. This may underline a process of "cell-cure" by DAAs, leading to a fast improvement of liver homeostasis