The new iminothiadiazole derivative VP1.14 ameliorates hippocampal damage after an excitotoxic injury.

Increased levels of glutamate causing excitotoxic damage accompany many neurological disorders. A well-characterized model of excitotoxic damage involves administration of kainic acid (KA), which causes limbic seizure activity and subsequent neuronal death, particularly in the CA1 and CA3 areas of the hippocampus. Inhibition of the enzyme glycogen synthase kinase-3 (GSK-3) and cAMP levels might play an important role in neuroprotection. As intracellular cAMP levels depend, in part, on the activity of the phosphodiesterase enzymes (PDEs), these enzymes have recently emerged as potential therapeutic targets for the treatment of several diseases. In previous works, we have shown a potent anti-inflammatory and neuroprotective effect of GSK-3 inhibition in a model of excitotoxicity, as well as a reduction of nigrostriatal dopaminergic neuronal cell death after phosphodiesterase 7 inhibition, which leads to an increase in cAMP levels. This study was undertaken to determine whether simultaneous inhibition of GSK-3 and PDE-7 by a novel 5-imino-1,2,4-thiadiazole compound, named VP1.14, could prevent the massive neuronal loss in the hippocampus evoked by intrahippocampal injection of KA. Here, we show that rats treated with VP1.14 showed a reduced inflammatory response after KA injection, and exhibited a significant reduction in pyramidal cell loss in the CA1 and CA3 areas of the hippocampus. Studies with hippocampal HT22 cells in vitro also showed a clear neuroprotective effect of VP1.14 and an anti-inflammatory effect shown by a decrease in the nitrite liberation and in the expression of pro-inflammatory cytokines by primary cultures of astrocytes treated with lipopolysaccharide.

Liver growth factor treatment reverses vascular and plasmatic oxidative stress in spontaneously hypertensive rats.

BACKGROUND: Liver growth factor (LGF) is an albumin-bilirubin complex with antioxidant actions in vitro. In spontaneously hypertensive rats (SHRs), short LGF treatment exerts antihypertensive and antifibrotic effects. METHOD: We aimed to determine if LGF treatment (4 i.p. injections, 4.5 µg/rat over 12 days) reduces oxidative stress in SHRs using Wistar-Kyoto (WKY) as control strain. We assessed the following: plasma oxidative stress biomarkers [protein-bound malondialdehyde (MDA); protein carbonyls and advanced glycation end products (AGEs)]; superoxide anion basal production in carotid artery-derived vascular smooth muscle cells (VSMCs) detected by dihydroethidium and confocal microscopy; and expression (western blot) and activities (spectroscopic methods) of NADPH and xanthine oxidases, CuZn, Mn and extracellular superoxide dismutases (SODs) and catalase in carotid arteries. RESULTS: LGF treatment had the following effects: reversed the increase in plasma MDA and protein carbonyls and VSMC superoxide anion levels observed in SHRs, without any effect on WKY strain; reversed the alterations in SHR vascular p22phox expression as well as NADPH oxidase, xanthine oxidase and catalase activities; had no effect on vascular CuZn-SOD and Mn-SOD expression or total SOD activity; and reversed the elevation in SHR vascular glycated/free extracellular-SOD expression ratio and plasma glucose without changes in plasma AGEs. CONCLUSION: LGF treatment of SHRs normalizes the level of plasma oxidative stress biomarkers through a reduction of vascular superoxide anion produced by NADPH and xanthine oxidases. These effects might be linked to the cardiovascular regenerative actions of LGF.

Liver growth factor treatment restores cell-extracellular matrix balance in resistance arteries and improves left ventricular hypertrophy in SHR.

Liver growth factor (LGF) is an endogenous albumin-bilirubin complex with antihypertensive effects in spontaneously hypertensive rats (SHR). We assessed the actions of LGF treatment on SHR mesenteric resistance and intramyocardial arteries (MRA and IMA, respectively), heart, and vascular smooth muscle cells (VSMC). SHR and Wistar-Kyoto (WKY) rats treated with vehicle or LGF (4.5 µg LGF/rat, 4 ip injections over 12 days) were used. Intra-arterial blood pressure was measured in anesthetized rats. The heart was weighted and paraffin-embedded. Proliferation, ploidy, and fibronectin deposition were studied in carotid artery-derived VSMC by immunocytochemistry. In MRA, we assessed: 1) geometry and mechanics by pressure myography; 2) function by wire myography; 3) collagen by sirius red staining and polarized light microscopy, and 4) elastin, cell density, nitric oxide (NO), and superoxide anion by confocal microscopy. Heart sections were used to assess cell density and collagen content in IMA. Left ventricular hypertrophy (LVH) regression was assessed by echocardiography. LGF reduced blood pressure only in SHR. LGF in vitro or as treatment normalized the alterations in proliferation and fibronectin in SHR-derived VSMC with no effect on WKY cells. In MRA, LGF treatment normalized collagen, elastin, and VSMC content and passive mechanical properties. In addition, it improved NO availability through reduction of superoxide anion. In IMA, LGF treatment normalized perivascular collagen and VSMC density, improving the wall-to-lumen ratio. Paired experiments demonstrated a partial regression of SHR LVH by LGF treatment. The effective cardiovascular antifibrotic and regenerative actions of LGF support its potential in the treatment of hypertension and its complications.

The antioxidant activity and thermal stability of lemon verbena (Aloysia triphylla) infusion.

Because of its good sensorial attributes, lemon verbena is used as a primary ingredient in infusions and nonalcoholic drinks. The present study was designed to assess the antioxidant activity (AA) of lemon verbena infusion (LVI) as well as the thermal stability of its AA and the content of polyphenolic compounds. The values reflecting the AA of LVI, including AA index, fast scavenging rate against 2,2-diphenyl-1-picrylhydrazyl, Trolox equivalent antioxidant capacity, and hydroxyl radical scavenging, are higher than those of many herbal infusions and antioxidant drinks estimated from reported data. In addition, the slope lag time and specific oxyradical antioxidant capacity values of LVI are comparable to those of a commercial antioxidant drink based on green tea. Hence, LVI is a source of bifunctional antioxidants, and thus in vivo studies of the antioxidant capacity of LVI would be useful to evaluate its potential as an ingredient in antioxidant drinks.

Antioxidant activity of liver growth factor, a bilirubin covalently bound to albumin.

We previously reported that treatment of spontaneously hypertensive rats (SHR) with liver growth factor (LGF), an albumin-bilirubin complex with a covalent bond, reduces blood pressure, improves nitric oxide (NO)-dependent vasodilatation, and exerts vascular antifibrotic actions. Because bilirubin, albumin, and albumin-bound bilirubins have antioxidant properties, we hypothesize that LGF might exert its cardiovascular actions through an antioxidant mechanism. We have tested in vitro the capacity of LGF to scavenge ABTS cation and peroxyl and hydroxyl radicals and to protect vascular NO from degradation by superoxide anion. We have also compared the antioxidant capacity of LGF with that of its molecular components albumin and bilirubin and the reference antioxidant trolox. LGF exhibited antioxidant capacity against all free radicals tested at lower concentrations than albumin, bilirubin, and trolox. LGF, bilirubin, and albumin were also able to protect endothelial NO from superoxide anion degradation in a fashion similar to that of superoxide dismutase or tiron, but at much lower concentrations. These data, together with our previous results in SHR, suggest that LGF might exert its cardiovascular regenerative actions, at least in part, through an antioxidant mechanism and that LGF could be a relevant circulating antioxidant in situations of oxidative stress.

Differences of peripheral inflammatory markers between mild cognitive impairment and Alzheimer's disease.

Multiple pathogenic factors may contribute to the pathophysiology of Alzheimer's disease (AD). Peripheral markers have been used to assess biochemical alterations associated with AD and mild cognitive impairment (MCI) involved in its pathophysiology. The present study was conducted to evaluate inflammatory peripheral markers in elderly patients with MCI, patients with AD and normal elderly subjects. We measured plasma levels of different cytokines (IL-6, TNF-alpha and IFN-alpha) and platelet levels of cyclooxigenase-2 (COX-2) from 34 patients with MCI, 45 patients with AD and 28 age-matched control subjects. MCI and AD patients showed similarities in TNF-alpha and COX-2 levels, and differences in IL-6 and INF-alpha. Whereas augmented IL-6 levels have been found in AD patients, a significant increase in INF-alpha has been detected only in patients with MCI possibly associated with the depression stage frequently found in cognitive impairment. In conclusion, inflammatory response may be an early factor in AD development and these changes in circulating markers are possibly related to the progression of MCI to AD.

Peripheral levels of glutathione and protein oxidation as markers in the development of Alzheimer's disease from Mild Cognitive Impairment.

There is a great interest in the relationship between Mild Cognitive Impairment (MCI) and the progression to Alzheimer's disease (AD). Several studies show the importance of oxidative stress in the pathogenesis of AD. The purpose of this study was the link between oxidative damage, MCI and AD. It analysed protein carbonyls and erythrocyte glutathione system plasma levels of 34 subjects with MCI, 45 subjects with AD and 28 age-matched control subjects. The results showed an increase in protein modification, a decrease in GSH levels and GSH/GSSG ratio in AD and MCI patients compared to age-matched control subjects (p<0.05). The present study shows that some peripheral markers of oxidative stress appear in MCI with a similar pattern to that observed in AD, which suggests that oxidative stress might represent a signal of the AD pathology. AD and MCI are biochemically equivalent. MCI does not necessarily need to progress to AD on a biochemical level.