Neurovascular hypoxia after mild traumatic brain injury in juvenile mice correlates with heart-brain dysfunctions in adulthood.

AIM: Retrospective studies suggest that mild traumatic brain injury (mTBI) in pediatric patients may lead to an increased risk of cardiac events. However, the exact functional and temporal dynamics and the associations between heart and brain pathophysiological trajectories are not understood. METHODS: A single impact to the left somatosensory cortical area of the intact skull was performed on juvenile mice (17 days postnatal). Cerebral 3D photoacoustic imaging was used to measure the oxygen saturation (sO2 ) in the impacted area 4 h after mTBI followed by 2D and 4D echocardiography at days 7, 30, 90, and 190 post-impact. At 8 months, we performed a dobutamine stress test to evaluate cardiac function. Lastly, behavioral analyses were conducted 1 year after initial injury. RESULTS: We report a rapid and transient decrease in cerebrovascular sO2 and increased hemoglobin in the impacted left brain cortex. Cardiac analyses showed long-term diastolic dysfunction and a diminished systolic strain response under stress in the mTBI group. At the molecular level, cardiac T-p38MAPK and troponin I expression was pathologic modified post-mTBI. We found linear correlations between brain sO2 measured immediately post-mTBI and long-term cardiac strain after 8 months. We report that initial cerebrovascular hypoxia and chronic cardiac dysfunction correlated with long-term behavioral changes hinting at anxiety-like and memory maladaptation. CONCLUSION: Experimental juvenile mTBI induces time-dependent cardiac dysfunction that corresponds to the initial neurovascular sO2 dip and is associated with long-term behavioral modifications. These imaging biomarkers of the heart-brain axis could be applied to improve clinical pediatric mTBI management.

4-Hydroxynonenal Contributes to Angiogenesis through a Redox-Dependent Sphingolipid Pathway: Prevention by Hydralazine Derivatives.

The neovascularization of atherosclerotic lesions is involved in plaque development and may contribute to intraplaque hemorrhage and plaque fragilization and rupture. Among the various proangiogenic agents involved in the neovascularization process, proatherogenic oxidized LDLs (oxLDLs) contribute to the formation of tubes via the generation of sphingosine 1-phosphate (S1P), a major mitogenic and proangiogenic sphingolipid mediator. In this study, we investigated whether 4-hydroxynonenal (4-HNE), an aldehydic lipid oxidation product abundantly present in oxLDLs, contributes to their proangiogenic properties. Immunofluorescence analysis of human atherosclerotic lesions from carotid endarterectomy showed the colocalization of HNE-adducts with CD31, a marker of endothelial cells, suggesting a close relationship between 4-HNE and neovessel formation. In vitro, low 4-HNE concentration (0.5-1 µM) elicited the formation of tubes by human microvascular endothelial cells (HMEC-1), whereas higher concentrations were not angiogenic. The formation of tubes by 4-HNE involved the generation of reactive oxygen species and the activation of the sphingolipid pathway, namely, the neutral type 2 sphingomyelinase and sphingosine kinase-1 (nSMase2/SK-1) pathway, indicating a role for S1P in the angiogenic signaling of 4-HNE. Carbonyl scavengers hydralazine and bisvanillyl-hydralazone inhibited the nSMase2/SK1 pathway activation and the formation of tubes on Matrigel® evoked by 4-HNE. Altogether, these results emphasize the role of 4-HNE in the angiogenic effect of oxLDLs and point out the potential interest of pharmacological carbonyl scavengers to prevent the neovascularization process.

Synthesis and evaluation of antioxidant phenolic diaryl hydrazones as potent antiangiogenic agents in atherosclerosis.

A series of bis-hydrazones derived from diaryl and diaryl ether hydroxybenzaldehyde frames 1 and 2 have been synthesized as potential antioxidant and antiangiogenic agents, two properties required to limit atherogenesis and cardiovascular events. These compounds were evaluated for their ability to neutralize free radical formation, to block endothelial cell-induced low-density lipoprotein oxidation (monitored by the formation of TBARS), an essential step in atherogenesis, and subsequent toxicity, to prevent angiogenesis evoked by low oxidized LDL concentration (monitored by the formation of capillary tubes on Matrigel) and to inhibit intracellular ROS increase involved in the angiogenic signaling. A structure/activity study has been carried out and finally allowed to select the phenolic diaryl ether hydralazine derivative 2a, sharing all these protective properties, as a promising hit for further development.

Antiatherogenic and antitumoral properties of Opuntia cladodes: inhibition of low density lipoprotein oxidation by vascular cells, and protection against the cytotoxicity of lipid oxidation product 4-hydroxynonenal in a colorectal cancer cellular model

Opuntia species have been used for thousands of years as a folk medicine in the treatment of diseases. However, the components and protective mechanisms are still unclear. We make the hypothesis that Opuntia species may protect the development of oxidative stress-associated diseases, such as atherosclerosis or colon cancer, via their antioxidant properties. We investigated the protective effect of Opuntia cladode powder against the oxidation of low-density lipoprotein (LDL) evoked by vascular endothelial cells, an important risk factor for atherosclerosis development, and the toxicity of 4-hydroxynonenal (a major lipid peroxidation product) on normal (Apc +/+) and preneoplastic (Apc min/+) immortalized epithelial colon cells. Various Opuntia species classified according to their degree of domestication, from the wildest (Opuntia streptacantha, Opuntia hyptiacantha, Opuntia megacantha), medium (Opuntia albicarpa), to the most domesticated (Opuntia ficus-indica) were tested. Cladode powders prepared from these Opuntia species significantly inhibited LDL oxidation induced by incubation with murine endothelial cells and the subsequent foam cell formation of RAW 264.7 murine macrophages and cytotoxicity on murine endothelial cells. Moreover, Opuntia cladode powder blocked the promotion of colon cancer development on an in vitro model of colonocytes. It may be noted that the phenolic acid and flavonoids content, the antioxidant capacity, and the protective effect were relatively similar in all the cladode powders from wild (O. streptacantha) and domesticated Opuntia. Altogether, these data confirm the therapeutic potential of Opuntia cladodes in diseases associated with oxidative stress

Escherichia coli morphological changes and lipid A removal induced by reduced pressure nitrogen afterglow exposure.

Lipid A is a major hydrophobic component of lipopolysaccharides (endotoxin) present in the membrane of most Gram-negative bacteria, and the major responsible for the bioactivity and toxicity of the endotoxin. Previous studies have demonstrated that the late afterglow region of flowing post-discharges at reduced pressure (1-20 Torr) can be used for the sterilization of surfaces and of the reusable medical instrumentation. In the present paper, we show that the antibacterial activity of a pure nitrogen afterglow can essentially be attributed to the large concentrations of nitrogen atoms present in the treatment area and not to the UV radiation of the afterglow. In parallel, the time variation of the inactivation efficiency quantified by the log reduction of the initial Escherichia coli (E. coli) population is correlated with morphologic changes observed on the bacteria by scanning electron microscopy (SEM) for increasing afterglow exposure times. The effect of the afterglow exposure is also studied on pure lipid A and on lipid A extracted from exposed E. coli bacteria. We report that more than 60% of lipid A (pure or bacteria-extracted) are lost with the used operating conditions (nitrogen flow QN2 = 1 standard liter per minute (slpm), pressure p = 5 Torr, microwave injected power PMW = 200 W, exposure time: 40 minutes). The afterglow exposure also results in a reduction of the lipid A proinflammatory activity, assessed by the net decrease of the redox-sensitive NFκB transcription factor nuclear translocation in murine aortic endothelial cells stimulated with control vs afterglow-treated (pure and extracted) lipid A. Altogether these results point out the ability of reduced pressure nitrogen afterglows to neutralize the cytotoxic components in Gram-negative bacteria.

Antiatherogenic and antitumoral properties of Opuntia cladodes: inhibition of low density lipoprotein oxidation by vascular cells, and protection against the cytotoxicity of lipid oxidation product 4-hydroxynonenal in a colorectal cancer cellular model.

Opuntia species have been used for thousands of years as a folk medicine in the treatment of diseases. However, the components and protective mechanisms are still unclear. We make the hypothesis that Opuntia species may protect the development of oxidative stress-associated diseases, such as atherosclerosis or colon cancer, via their antioxidant properties. We investigated the protective effect of Opuntia cladode powder against the oxidation of low-density lipoprotein (LDL) evoked by vascular endothelial cells, an important risk factor for atherosclerosis development, and the toxicity of 4-hydroxynonenal (a major lipid peroxidation product) on normal (Apc +/+) and preneoplastic (Apc min/+) immortalized epithelial colon cells. Various Opuntia species classified according to their degree of domestication, from the wildest (Opuntia streptacantha, Opuntia hyptiacantha, Opuntia megacantha), medium (Opuntia albicarpa), to the most domesticated (Opuntia ficus-indica) were tested. Cladode powders prepared from these Opuntia species significantly inhibited LDL oxidation induced by incubation with murine endothelial cells and the subsequent foam cell formation of RAW 264.7 murine macrophages and cytotoxicity on murine endothelial cells. Moreover, Opuntia cladode powder blocked the promotion of colon cancer development on an in vitro model of colonocytes. It may be noted that the phenolic acid and flavonoids content, the antioxidant capacity, and the protective effect were relatively similar in all the cladode powders from wild (O. streptacantha) and domesticated Opuntia. Altogether, these data confirm the therapeutic potential of Opuntia cladodes in diseases associated with oxidative stress.

Annexin II-dependent actin remodelling evoked by hydrogen peroxide requires the metalloproteinase/sphingolipid pathway.

Actin remodeling is a dynamic process associated with cell shape modification occurring during cell cycle and proliferation. Oxidative stress plays a role in actin reorganization via various systems including p38MAPK. Beside, the mitogenic response evoked by hydrogen peroxide (H2O2) in fibroblasts and smooth muscle cells (SMC) involves the metalloproteinase (MMPs)/sphingomyelinase 2 (nSMase2) signaling pathway. The aim of this work was to investigate whether this system plays a role in actin remodeling induced by H2O2. Low H2O2 dose (5µM) rapidly triggered a signaling cascade leading to nSMase2 activation, src and annexin 2 (AnxA2) phosphorylation, and actin remodeling, in fibroblasts and SMC. These events were blocked by pharmacological inhibitors of MMPs (Ro28-2653) and p38MAPK (SB203580), and were lacking in MMP2(-/-) and in nSMase2-mutant (fro) fibroblasts. Likewise, H2O2 was unable to induce actin remodeling in fro and MMP2(-/-) fibroblasts or in cells pretreated with p38MAPK, or MMP inhibitors. Finally we show that nSMase2 activation by H2O2, depends on MMP2 and p38MAPK, and is required for the src-dependent phosphorylation of AnxA2, and actin remodeling. Taken together, these findings indicate for the first time that AnxA2 phosphorylation and actin remodeling evoked by oxidative stress depend on the sphingolipid pathway, via MMP2 and p38MAPK.

Synthesis, antioxidant and cytoprotective evaluation of potential antiatherogenic phenolic hydrazones. A structure-activity relationship insight.

A novel series of hydrazones derived from substituted benzaldehydes have been synthesized as potential antiatherogenic agents. Several methods were used for exploring their antioxidant and cytoprotective properties, such as their scavenging effect on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, the inhibition of superoxide anion (O2(·-)) generation and the measurement of cell-induced low-density lipoprotein oxidation (monitored by the formation of TBARS). The cytoprotective efficacy was also evaluated by measuring the cell viability (monitored by the MTT assay) in the presence of cytotoxic oxidized LDL. In this report, we discuss the relationship between the chemical structure of phenolic hydrazones and their antioxidant and cytoprotective activities, for subsequent application as antiatherogenic agents. This SAR study confirms that the phenolic frame is not the only prerequisite for antioxidant activity and N-methylbenzothiazole hydrazone moiety magnifies the dual required properties in two most interesting derivatives.

Protein disulfide isomerase modification and inhibition contribute to ER stress and apoptosis induced by oxidized low density lipoproteins.

AIMS: Protein disulfide isomerase (PDI) is an abundant endoplasmic reticulum (ER)-resident chaperone and oxidoreductase that catalyzes formation and rearrangement (isomerization) of disulfide bonds, thereby participating in protein folding. PDI modification by nitrosative stress is known to increase protein misfolding, ER stress, and neuronal apoptosis. As LDL oxidation and ER stress may play a role in atherogenesis, this work was designed to investigate whether PDI was inactivated by oxLDLs, thereby participating in oxLDL-induced ER stress and apoptosis. RESULTS: Preincubation of human endothelial HMEC-1 and of macrophagic U937 cells with toxic concentration of oxLDLs induced PDI inhibition and modification, as assessed by 4-HNE-PDI adducts formation. PDI inhibition by bacitracin potentiated ER stress (increased mRNA expression of CHOP and sXBP1) and apoptosis induced by oxLDLs. In contrast, increased PDI activity by overexpression of an active wild-type PDI was associated with reduced oxLDL-induced ER stress and toxicity, whereas the overexpression of a mutant inactive form was not protective. These effects on PDI were mimicked by exogenous 4-HNE and prevented by the carbonyl-scavengers N-acetylcysteine and pyridoxamine, which reduced CHOP expression and toxicity by oxLDLs. Interestingly, 4-HNE-modified PDI was detected in the lipid-rich areas of human advanced atherosclerotic lesions. Innovation and CONCLUSIONS: PDI modification by oxLDLs or by reactive carbonyls inhibits its enzymatic activity and potentiates both ER stress and apoptosis by oxLDLs. PDI modification by lipid peroxidation products in atherosclerotic lesions suggests that a loss of function of PDI may occur in vivo, and may contribute to local ER stress, apoptosis, and plaque progression.

Synthesis and antioxidant activity evaluation of a syringic hydrazones family.

A novel series of hydrazones derived from syringaldehyde and their antioxidant properties have been explored. Several employed methods such as scavenging effect on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS(+)) radical cation expressed as Trolox equivalent antioxidant capacity (TEAC), inhibition of superoxide anion (O(2)(-)) generation and of human cell-mediated low-density lipoprotein oxidation (monitored by the formation of TBARS) exhibited their potent antioxidant properties. The carbonyl scavenger efficacy was also evaluated by measuring the ability to decrease the protein carbonyl content in cells challenged with oxidized LDL. In this report, we discuss about the synthesis of hydrazones and their dual biological role, antioxidant and carbonyl scavenger for further application in atherosclerosis.