Tick-borne encephalitis – lipid peroxidation and its consequences

Background: The purpose of this study was to assess the processes of lipid peroxidation with prostaglandin derivatives and reactive aldehydes being its major indicators in cerebrospinal fluid (CSF), plasma and urine of patients with tick-borne encephalitis (TBE). Materials and methods: This study included 60 patients with TBE and 56 healthy subjects. Lipid peroxidation was estimated by the measurement of 4-hydroxynonenal (4-HNE), 4-hydroxyhexenal (4-HHE), malondialdehyde (MDA), acrolein, crotonaldehyde, and 4-oxononenal (4-ONE), determined by GC-MS, F₂-isoprostanes and neuroprostanes (NPs) level determined by LC-MS. The level of 4-HNE-protein adducts was determined by ELISA. Phospholipase A₂ (PLA₂), platelet-activating factor acetylhydrolase (PAF-AH) and glutathione peroxidase (GSH-Px) activities and vitamin E level were determined spectrophotometrically and by HPLC, respectively. In parallel, the plasma levels of phospholipid acids such as arachidonic acid (AA), linoleic acid (LA) and docosahexaenoic acid (DHA) were monitored. Results: A significant decrease in AA, LA, DHA level and GSH-Px activity (by about 20, 69, 11 and 18%, respectively) was observed. The consequence of enhanced phospholipid peroxidation was almost 7 times higher plasma level of F₂-isoprostanes and 3-fold increase in NPs level in CSF of TBE patients. Additionally a 3.5-fold increase in the CSF level of MDA, 5-fold increase in the plasma level of 4-HNE and urine level of 4-HHE in TBE patients was observed. Decreased plasma activity of PLA₂ with an increase in the PAF-AH activity was observed. Conclusion: Lipid peroxidation occurring during TBE development indicates its relevance in pathophysiology of this disease. Moreover lipid peroxidation products might be useful for the diagnosis of TBE.     

Early onset of lipid peroxidation after human traumatic brain injury: a fatal limitation for the free radical scavenger pharmacological therapy?

BACKGROUND: On the basis of the contradiction between data on experimental head trauma showing oxidative stress-mediated cerebral tissue damage and failure of the majority of clinical trials using free radical scavenger drugs, we monitored the time-course changes of malondialdehyde (MDA, an index of cell lipid peroxidation), ascorbate, and dephosphorylated ATP catabolites in cerebrospinal fluid (CSF) of traumatic brain-injured patients. METHODS: CSF samples were obtained from 20 consecutive patients suffering from severe brain injury. All patients were comatose, with a Glasgow Coma Scale on admission of 6 +/- 1. The first CSF sample for each patient was collected within a mean value of 2.95 hours from trauma (SD=1.98), after the insertion of a ventriculostomy catheter for the continuous monitoring of intracranial pressure. During the next 48 hours, CSF was withdrawn from each patient once every 6 hours. All samples were analyzed by an ion-pairing high-performance liquid chromatographic method for the simultaneous determination of MDA, ascorbic acid, hypoxanthine, xanthine, uric acid, inosine, and adenosine. RESULTS: In comparison with values recorded in 10 herniated-lumbar-disk, noncerebral control patients, data showed that all CSF samples of brain-injured patients had high values (0.226 micromol/L; SD=0.196) of MDA (undetectable in samples of control patients) and decreased ascorbate levels (96.25 micromol/L; SD=31.74), already at the time of first withdrawal at the time of hospital admission. MDA was almost constant in the next two withdrawals and tended to decrease thereafter, although 48 hours after hospital admission, a mean level of 0.072 micromol/L CSF (SD=0.026) was still recorded. The ascorbate level was normalized 42 hours after hospital admission. Changes in the CSF values of ATP degradation products (oxypurines and nucleosides) suggested a dramatic alteration of neuronal energy metabolism after traumatic brain injury. CONCLUSIONS: On the whole, these data demonstrate the early onset of oxygen radical-mediated oxidative stress, proposing a valid explanation for the failure of clinical trials based on the administration of oxygen free radical scavenger drugs and suggesting a possible rationale for testing the efficacy of lipid peroxidation "chain breakers" in future clinical trials.     

Value of MRI in the evaluation of lipid storage myopathy

AIM:To investigate the magnetic resonance imaging(MRI)findings of lipid storage myopahty(LSM)，evaluate the clinical value of MRI for LSM.and thigh,spin echo sequence,fast spin echo sequence and short tau inversion recovery(STIR)were utilized .RESULTS:The signal intensity of diseased muscle of 8 cases with LSM was hyperintense on T2-weighted images (T2WI) and T1-weighed images (T1WI),and hyperintense signal intensity on T2WI and iso-intense on T1WI was seen on 2 patients as well.CONCLUSION:MRI can provide objective data for clinical diagnosis,therapeutic evaluation and folow-up.It can also help th decide the accurate localiztions for biopsies.     

Do platelet apoptosis, activation, aggregation, lipid peroxidation and platelet-leukocyte aggregate formation occur simultaneously in hyperlipidemia?

OBJECTIVES: The circulating lipoproteins may cause some abnormalities in platelet composition and function in hypercholesterolemia. The aim of this study was to investigate whether platelet apoptosis, platelet activation, platelet aggregation, platelet-leukocyte aggregate (PLA) formation and lipid peroxidation occur simultaneously in hyperlipidemia. DESIGN AND METHODS: Expression of GpIIb/IIIa (CD41a), P-selectin (CD62-P), platelet-bound fibrinogen (antifibrinogen), platelet membrane phosphatidylserine (PS), platelet-monocyte aggregates (mono-PLA) and platelet-neutrophil aggregates (neut-PLA) was measured in eight hyperlipidemic and eight normal subjects using flow cytometry. ADP (10 microM) was used to activate platelets. Furthermore, ADP induced platelet aggregation responses, platelet malondialdehyde (MDA) and glutathione (GSH) levels were determined. RESULTS: Before platelet activation, platelet CD62-P, antifibrinogen, annexin-V, mono-PLA, neut-PLA and platelet MDA levels as well as platelet aggregation responses in the hyperlipidemics were significantly higher than those in the controls (P<0.01, P<0.01, P<0.01, P<0.001, P<0.001, P<0.01, P<0.001, respectively), whereas GpIIb/IIIa expression and GSH levels were not different significantly (P > 0.05). In the control group, CD62-P, antifibrinogen and annexin-V levels increased significantly after ADP activation (P<0.05, P<0.05, P<0.01, respectively). In hyperlipidemic subjects, annexin-V expression increased significantly after activation (P<0.01), whereas expression of GpIIb/IIIa, CD62-P and antifibrinogen remained unchanged (P>0.05). The levels of total cholesterol (T-CHO), low density lipoprotein cholesterol (LDL-C), serum fibrinogen (S-FGN) and high density lipoprotein cholesterol (HDL-C) in patients were found to be correlated with platelet CD62-P, antifibrinogen, annexin-V, mono-PLA and MDA. CONCLUSIONS: In conclusion, it seems that in hyperlipidemia, some platelets are in an activated state in circulation, and that increased lipid peroxidation, early apoptosis, platelet-leukocytes aggregate formation and platelet aggregation altogether accompany this process.     

How do conventional markers of lipid disorders compare with apolipoproteins?

Assessment of risk for coronary heart disease (CHD) indicates that apolipoprotein B and apolipoprotein A-I and their ratio are efficient predictors, possibly superior to hitherto used indicators, i.e. S-Cholesterol, S-Triglycerides, S-HDL cholesterol and S-LDL cholesterol. We used the ratio S-Apolipoprotein B/S-Apolipoprotein A-I as the gold standard to compare the diagnostic performance of the other properties based on consecutive routine measurements in patients attending primary health-care or a university hospital. The different cut-offs of the S-Apolipoprotein B/S-Apolipoprotein A-I ratio that were investigated created a prevalence of risk factors that might require intervention in the study group between 10 and 77%. The gender difference prompts for a partitioning related to the gender, whereas the changes related to age were small and were disregarded. The diagnostic sensitivity and specificity were demonstrated in ROC diagrams for the studied properties.     

Can measurement of serum apolipoprotein B replace the lipid profile monitoring of patients with lipoprotein disorders?

BACKGROUND: Current clinical guidelines require that five indices (total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, and the total/HDL cholesterol ratio) be measured or calculated to assess the lipid-related risk of vascular disease. All five are also targets of therapy and therefore all must be measured initially and at follow-up. Considerable evidence indicates that apolipoprotein B (apo B) is a better index of reaching or not reaching treatment targets than total or LDL cholesterol. METHODS: The objective of this study was to examine whether measurement of a single marker (apo B) led to the same categorization of risk as the traditional five indices (lipid profile). If both apo B and lipid profile indicated that the patient was either within or outside their respective treatment targets, the indices were considered concordant. If not, the indices were considered discordant. Concordance/discordance was examined in 215 patients at their first and last clinic visit. RESULTS: Concordance was high in both higher (88% at the first and 92% at the last clinic visit) and lower (76% at the first and 78% at the last clinic visit) risk groups at both the initial and final visits. Discordance was virtually restricted to the group with hypertriglyceridemia with normal concentrations of apo B, a group in which little independent evidence points to any substantially increased risk of vascular disease. CONCLUSIONS: These data raise the possibility that at least for high risk patients treated with statins, follow-up could be simplified and expenses reduced if only apo B were measured. They also raise the possibility that outcome might be improved if the therapeutic algorithm were simplified.     

Neuroprotective effects of 17β-estradiol after hypovolemic cardiac arrest in immature piglets: the role of nitric oxide and peroxidation

We recently reported that cerebral and cardiac injuries are mitigated in immature female piglets after severe hemorrhage with subsequent cardiac arrest. Female sex was also associated with a smaller increase in the cerebral expression of inducible nitric oxide synthase (iNOS) and neuronal nitric oxide synthase (nNOS). In the current study, we tested the hypothesis that exogenously administered 17β-estradiol (E?) can improve neurological outcome by NOS modulation. Thirty-nine sexually immature piglets were bled to a mean arterial pressure of 35 mmHg over 15 min. Fifty micrograms per kilogram of E? was then administered to 10 male and 10 female animals (estradiol group), whereas control animals (n = 10 males and 9 females) received equal volume of normal saline. The animals were then subjected to ventricular fibrillation (4 min) followed by up to 15 min of open-chest cardiopulmonary resuscitation. Vasopressin 0.4 U · kg?1 and amiodarone 0.5 mg · kg?1 were given, and 3 mL · kg?1 of 7.5% saline with 6% dextran was administered over 20 min. All surviving animals were killed after 3 h, and their brains examined for histological injury and NOS expression. No significant differences were observed in survival or hemodynamics between the groups. Compared with the control group, animals in the E? group exhibited a significantly smaller increase in nNOS and iNOS expression, a smaller blood-brain-barrier disruption, and a mitigated neuronal injury. There was a significant correlation between nNOS and iNOS levels and neuronal injury. Interestingly, estradiol attenuated cerebral damage (including lower activation of nNOS and iNOS) both in male and female piglets. In conclusion, in our immature piglet model of hypovolemic cardiac arrest, E? downregulates iNOS and nNOS expression and results in decreased blood-brain-barrier permeability disruption and smaller neuronal injury.     

Effect of dietary alpha‐ketoglutarate on blood lipid profile during hypercholesterolaemia in rats

Objective. The aim of the study was to determine the effect of α‐ketoglutarate on the blood lipid profile using a rat animal model with experimentally induced hypercholesterolaemia. Material and methods. The female and male (30/30) Wistar rats had ad libitum access to a diet containing cholesterol (1?%) and lard (10?%) throughout the entire experimental period (120 days). On day 60 of the study, both the females and the males were divided into three groups, the first receiving a mixture of drinking water adjusted to pH?4.6 using HCl (control), the other two (experimental groups) receiving a solution containing 0.01?M and 0.1?M α‐ketoglutarate (AKG) (pH adjusted to 4.6). Blood samples were taken on days 0, 30, 60 and 120. Results. The concentrations of total cholesterol, triglycerides, HDL and LDL, respectively, in the blood serum were estimated spectrophotometrically. During the entire experimental period the total cholesterol, triglycerides and LDL levels of the control rats increased, whereas that of HDL decreased. The serum concentrations of total cholesterol, LDL and triglycerides in both the experimental groups receiving AKG decreased (days 60 to 120) (p<0.05), while the HDL concentration tended to increase. The body gain in all groups receiving AKG was significantly lower than in the control group. Conclusions. These observations clearly prove that oral treatment with AKG can decrease the risk of hypercholesterolaemia developing and can lower the body weight. The relative concentrations of the plasma LDL and HDL changed to a more favourable ratio promoting good health.     

Are the lipid-modifying effects of fibrates mediated by alterations in plasma lipid transfer activity?

Fenofibrate, a PPAR-alpha (peroxisome-proliferator-activated receptor-alpha) agonist, has been shown to modify plasma lipid and lipoprotein composition and metabolism by a variety of mechanisms. In addition, fenofibrate has been shown to increase the activity of PLTP (phospholipid transfer protein) and to reduce the activity of CETP (cholesteryl ester transfer protein). It is not known, however, whether the changes in PLTP and CETP plasma activity play an active role in the lipid changes observed with fenofibrate therapy, and this is investigated by Watts and co-workers in the present issue of Clinical Science.     

Role of intravenous lipid emulsions in the management of calcium channel blocker and β-blocker overdose: 3 years experience of a university hospital

Objectives: The objective of this study was to assess the efficacy of lipid emulsion as antidotal therapy in severe calcium channel blocker (CCB) and β-blocker (BB) intoxications. Patients and methods: This is a retrospective study in which we have summarized data of patients who were admitted to a university-based emergency department in a period of 3 years and were given intravenous lipid emulsion (ILE) to manage cardiogenic shock due to CCB and BB overdose. Results: We identified 15 patients who received ILE therapy for CCB and BB toxicity. Hospitalization durations variated between 3 and 33 days (mean 7.46 ± 7.41 days). Drug exposures included CCBs (n = 8, 53.3%), CCBs and paracetamol (n = 1, 6.6%), and BBs (n = 6, 40%). ILE therapy was effective in 12 patients (80%). Three patients (20%) had resistant hypotension, one of whom progressed to pulmonary edema. Adverse effects of ILE therapy were seen in three patients (20%). Two patients underwent mechanical ventilation. Two patients developed hypoxic ischemic encephalopathy, one patient died, and 14 patients (93.3%) were discharged from hospital. Conclusion: There was 93.3% survival in patients receiving ILE for drug-induced cardiovascular collapse. Clinically significant adverse effects were uncommon. We suggest ILE administration for the treatment of cardiogenic shock due to CCB and BB overdose.     

Formation and aggregation of lipid rafts in γδ T cells following stimulation with Mycobacterium tuberculosis antigens

Lipid rafts are plasma membrane microdomains that are implicated in diverse signaling pathways in immune cells. Based on the distinct types of T-cell receptors, two T-cell subpopulations have been identified: αβ and γδ T cells. In humans, γδ T cells represent a relatively rare T lymphocyte population but play a critical role in the immune response to infection by Mycobacterium tuberculosis. It has been demonstrated that Mycobacterium tuberculosis antigens (Mtb-Ag) preferentially activate γδ T cells. Thus, we investigated whether lipid rafts are involved in the Mtb-Ag-mediated activation of γδ T cells. Human peripheral blood mononuclear cells (PBMCs) were stimulated with Mtb-Ag, and expression of a lipid raft marker ganglioside GM1 (GM1) was determined by flow cytometry. The aggregation of lipid rafts was evaluated by laser confocal microscopy. Non-stimulated fresh PBMCs minimally expressed GM1 (6.55 ± 2.01%) and had no aggregated rafts in γδ T cells. Mtb-Ag stimulation gradually increased the expression of GM1 in a time-dependent manner. At 72 h, the majority of γδ T cells expressed GM1 (88.69 ± 7.55%). Furthermore, accompanied with the increased expression of GM1, aggregation of lipid rafts became gradually visible in γδ T cells. The aggregated rafts, however, were not evenly distributed and only occurred over a small portion of GM1-positive cells. Pretreatment with methyl-β-cyclodextrin, a cholesterol-depleting reagent, completely inhibited the Mtb-Ag-mediated aggregation of lipid rafts. These results demonstrate that lipid raft aggregation occurs in Mtb-Ag-activated γδ T cells, suggesting that lipid rafts are involved in activation of γδ T cells.     

Improvement of myocardial blood flow by lipid‐lowering therapy with pravastatin is modulated by apolipoprotein E genotype

Objective. Apolipoprotein E (apoE) polymorphism affects the risk of advanced coronary artery disease, but its role in early atherosclerosis remains unknown. We used positron emission tomography (PET) to study whether coronary reactivity or its response to pravastatin is related to the apoE genotype. Material and methods. Samples from 44 mildly hypercholesterolaemic men (aged 35±4 years) of an earlier trial were re‐analysed according to apoE genotype. Subjects were randomized to receive either 40?mg/day pravastatin or placebo for 6 months. To assess coronary reactivity, myocardial blood flow was measured by PET at rest and during adenosine infusion. PET studies and lipid analyses were done at baseline and after 6 months of therapy. Results. There were no differences between apoE ?3/3 and ?4/3 genotypes in basal or adenosine‐stimulated flow or in coronary flow reserve (CFR) at baseline. There was a significant apoE genotype‐by‐treatment group interaction regarding the change in adenosine‐stimulated flow (ANCOVA; p = 0.018) and CFR (p = 0.020) at the end of the study. In the pravastatin group, the adenosine‐stimulated flow increased by 32.5?% in subjects with ?3/3 (n = 9), but decreased non‐significantly (?14.4?%) in subjects with ?4/3 (n = 9) (p = 0.0009). The corresponding changes in CFR were +17.8?% for ?3/3 and (?11.9?% for ?4/3 (p = 0.05). There were no significant changes from the baseline values in placebo recipients. After pravastatin treatment, both genotype groups showed a similar decrease in serum total and low‐density lipoprotein cholesterol (p<0.0001 for both). Conclusions. Coronary function improves by 6 months of pravastatin in subjects with the apoE ?3/3 genotype, but not in those with the ?4/3.