Foetal lipoprotein oxidation and preeclampsia.

Preeclampsia (PE) is a multisystemic syndrome specific to pregnancy. Although PE is the leading cause of death from complications associated with pregnancy, its aetiology is still unknown. In PE, lipid metabolism is altered. When lipids are damaged, both the mother and the foetus may be at risk. Lipoproteins contain apolipoproteins, triacylglycerols, free and esterified cholesterol, and phospholipids, all of which are susceptible to oxidative stress when high levels of oxygen and nitrogen free radicals are present. Lipoperoxidation can occur in three stages: mild, moderate, and severe. In severe lipid damage, highly toxic products such as malondialdehyde (MDA) can be generated; under these conditions, low-density lipoprotein (LDL) proteins can be oxidized (oxLDL). oxLDL is a biomolecule that can affect the production of nitric oxide (NO), the main vasodilator derived from the endothelium. oxLDL can interfere with the transduction of the signals responsible for triggering the activation of endothelial nitric oxide synthase (eNOS), causing reduced vasodilation and endothelial dysfunction, which are the main characteristics of preeclampsia. The objective of the review was to analyse the information the current information about exists about the impact generated by the oxidation of LDL and HDL lipoproteins in neonates of women with preeclampsia and how these alterations can predispose the neonate to develop diseases in adulthood.PE can cause foetal loss, intrauterine growth restriction, or developmental complications. Neonates of mothers with PE have a high risk of cardiovascular diseases, stroke, mental retardation, sensory deficiencies and an increased risk of developing metabolic diseases. PE not only affects the foetus, generating complications during pregnancy but also predisposes them to chronic diseases in adulthood.

Oxidative Stress in Spinocerebellar Ataxia Type 7 Is Associated with Disease Severity.

Spinocerebellar ataxia type 7 is a neurodegenerative inherited disease caused by a CAG expansion in the coding region of the ATXN7 gene, which results in the synthesis of polyglutamine-containing ataxin-7. Expression of mutant ataxin-7 disturbs different cell processes, including transcriptional regulation, protein conformation and clearance, autophagy, and glutamate transport; however, mechanisms underlying neurodegeneration in SCA7 are still unknown. Implication of oxidative stress in the pathogenesis of various neurodegenerative diseases, including polyglutamine disorders, has recently emerged. We perform a cross-sectional study to determine for the first time pheripheral levels of different oxidative stress markers in 29 SCA7 patients and 28 age- and sex-matched healthy subjects. Patients with SCA7 exhibit oxidative damage to lipids (high levels of lipid hydroperoxides and malondialdehyde) and proteins (elevated levels of advanced oxidation protein products and protein carbonyls). Furthermore, SCA7 patients showed enhanced activity of various anti-oxidant enzymes (glutathione reductase, glutathione peroxidase, and paraoxonase) as well as increased total anti-oxidant capacity, which suggest that activation of the antioxidant defense system might occur to counteract oxidant damage. Strikingly, we found positive correlation between some altered oxidative stress markers and disease severity, as determined by different clinical scales, with early-onset patients showing a more severe disturbance of the redox system than adult-onset patients. In summay, our results suggest that oxidative stress might contribute to SCA7 pathogenesis. Furthermore, oxidative stress biomarkers that were found relevant to SCA7 in this study could be useful to follow disease progression and monitor therapeutic intervention.

Oxidative modifications of foetal LDL-c and HDL-c lipoproteins in preeclampsia.

BACKGROUND: Oxidative modifications have been observed in lipids and proteins in lipoproteins isolated from women with preeclampsia. Thus, newborns could also be susceptible to this damage directly through their mothers. In this study, we evaluated the oxidative profile of LDL-c and HDL-c lipoproteins isolated from the umbilical cord from newborns born to women with preeclampsia. METHODS: Thirty newborns born to women with preeclampsia and thirty newborns born to women with healthy pregnancies were included. Lipid-damage biomarkers, including conjugated dienes, lipohydroperoxides and malondialdehyde, were measured. The reduction of nitroblue tetrazolium, formation of dityrosines, and carbonylation of proteins were assessed as indicators of protein damage. The protective activity of paraoxonase-I on HDL-c particles was evaluated. The total antioxidant capacity and lipid profiles were quantified in plasma. Data were analysed using Student's t-tests and Pearson correlation coefficients. RESULTS: Compared with the control group, the preeclampsia group had an increase in the percentage of lipid damage in both lipoproteins. There was an increase of 23.3 and 19.9% for conjugated dienes, 82.4 and 21.1% for lipohydroperoxides, and 103.8 and 51.5% for malondialdehyde in LDL-c and HDL-c, respectively. However, these infants did not show evident damage in protein oxidation. The activity of the enzyme paraoxonase-I was decreased by 36.2%; by contrast, the total antioxidant capacity was increased by 40% (protein) and 28.8% (non-protein). CONCLUSIONS: The oxidative modifications that occur in HDL-c and LDL-c isolated from newborns from women with preeclampsia are mainly caused by lipoperoxidation processes related to evident paraoxonase-I inactivation. The absence of protein damage is likely linked to an increase in total antioxidant capacity. Therefore, antioxidant support could be helpful in reducing oxidative stress in mother/newborn dyads.

Oxidative profiles of LDL and HDL isolated from women with preeclampsia.

BACKGROUND: Oxidative stress causes biochemical changes in lipids and proteins; these changes can induce damage to the vascular endothelium and create maternal complications that are characteristic of preeclampsia. In this study, we evaluated the oxidative profile of lipoproteins isolated from women with preeclampsia. METHODS: Thirty women diagnosed with preeclampsia and thirty women without preeclampsia were included in the study. Lipid-damage biomarkers, including conjugated dienes, lipohydroperoxides and malondialdehyde, were measured. The reduction of nitroblue tetrazolium, the formation of dityrosines, and the carbonylation of proteins were assessed as indicators of protein damage. The protective activity of HDL-c was evaluated by the paraoxonase-I activity present on the HDL-c particles. Serum lipid profiles were also quantified in both groups. Data were analysed using Student's t test and the Pearson correlation coefficient. RESULTS: Our results demonstrated in PE women evident oxidative changes in the lipids and proteins in HDL-c and LDL-c particles and the activity of the antioxidant enzyme PON-I decreased 59.9%. HDL-c exhibited self-defence, as demonstrated by the negative correlation between paraoxonase-I activity and the formation of lipohydroperoxides in HDL-c (r = -0.3755, p < 0.005). CONCLUSIONS: LDL-c and HDL-c isolated from women with preeclampsia show oxidative damage to lipids and proteins. We propose an oxidative profile based on the oxidation levels indicated by each of the markers used. We also found that paraoxonase-I is inactivated in the presence of lipohydroperoxides. Antioxidant support might be helpful to reduce oxidative stress in patients with preeclampsia. Further investigations are necessary to define the association between antioxidant activities and preeclampsia.