Cholesterol and neurodegeneration: longitudinal changes in serum cholesterol biomarkers are associated with new lesions and gray matter atrophy in multiple sclerosis over 5 years of follow-up.

BACKGROUND AND PURPOSE: Cholesterol is an important structural component of myelin and essential for brain homeostasis. Our objective was to investigate whether longitudinal changes in cholesterol biomarkers are associated with neurodegeneration in multiple sclerosis (MS). METHODS: This prospective, longitudinal study (n = 154) included 41 healthy controls, 76 relapsing-remitting MS subjects and 37 progressive MS subjects. Neurological examination, brain magnetic resonance imaging and blood samples were obtained at baseline and at 5-year follow-up visits. Cholesterol biomarkers measured included plasma total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol and the apolipoproteins ApoA-I, Apo-II, ApoB, ApoC-II and ApoE. Key cholesterol pathway single nucleotide polymorphisms were genotyped. RESULTS: Greater percentage increases in HDL-C and ApoA-I levels were associated with a lower rate of gray matter and cortical volume loss. Greater percentage increases in low-density lipoprotein cholesterol were associated with increases in new T2 lesions. The percentage increases in HDL-C (P = 0.032) and ApoA-I (P = 0.007) were smaller in patients with relapsing-remitting MS at baseline who converted to secondary progressive MS during the 5-year follow-up period. Changes in HDL-C and ApoA-I were associated with lipoprotein lipase rs328 genotype status. CONCLUSIONS: Increases in HDL-C and ApoA-I have protective associations with magnetic resonance imaging measures of neurodegeneration in MS.

Tannerella forsythia-produced methylglyoxal causes accumulation of advanced glycation endproducts to trigger cytokine secretion in human monocytes.

The periodontal pathogen Tannerella forsythia has the unique ability to produce methylglyoxal (MGO), an electrophilic compound which can covalently modify amino acid side chains and generate inflammatory adducts known as advanced glycation endproducts (AGEs). In periodontitis, concentrations of MGO in gingival-crevicular fluid are increased and are correlated with the T. forsythia load. However, the source of MGO and the extent to which MGO may contribute to periodontal inflammation has not been fully explored. In this study we identified a functional homolog of the enzyme methylglyoxal synthase (MgsA) involved in the production of MGO in T. forsythia. While wild-type T.forsythia produced a significant amount of MGO in the medium, a mutant lacking this homolog produced little to no MGO. Furthermore, compared with the spent medium of the T. forsythia parental strain, the spent medium of the T. forsythia mgsA-deletion strain induced significantly lower nuclear factor-kappa B activity as well as proinflammogenic and pro-osteoclastogenic cytokines from THP-1 monocytes. The ability of T. forsythia to induce protein glycation endproducts via MGO was confirmed by an electrophoresis-based collagen chain mobility shift assay. Together these data demonstrated that T. forsythia produces MGO, which may contribute to inflammation via the generation of AGEs and thus act as a potential virulence factor of the bacterium.

Associations between follicular fluid high density lipoprotein particle components and embryo quality among in vitro fertilization patients.

PURPOSE: Follicular redox balance is likely to be important for embryo quality during in vitro fertilization (IVF), and the anti-oxidative high desity lipoprotein (HDL) particle is the sole lipoprotein measured in follicular fluid (FF). Therefore, we investigated FF HDL particle components as predictors of embryo quality during IVF. METHODS: Two research follicles collected from each participant were individually tracked, and 103 women having at least one developed embryo were included in the analysis. Concentrations of 15 non-cholesterol HDL particle components and 26 HDL-cholesterol (HDL-C) particle size subfractions were determined. Embryo quality was assessed for embryo cell number, embryo fragmentation, and embryo symmetry. Multivariable Poisson regression with a sandwich variance estimator was used to evaluate associations between HDL particle components and embryo quality, adjusted for covariates. RESULTS: Higher γ-tocopherol concentration was associated with less embryo fragmentation (relative risk [RR] = 4.43; 95 % confidence interval [CI] 1.78, 11.06), and higher apolipoprotein A-1 concentration was associated with full embryo symmetry (RR = 3.92; 95 % CI 1.56, 9.90). Higher concentrations of HDL-C subfractions in the large and medium particle size ranges were associated with poorer embryo quality. CONCLUSIONS: FF HDL lipophilic micronutrients and protein components, as well as HDL-C particle size, may be important predictors of embryo quality during IVF.

Lipid concentrations and semen quality: the LIFE study.

The decline in sperm count rates over the last 50 years appears to parallel the rising prevalence of obesity. As lipid levels are strongly associated with obesity, high lipids levels or hyperlipidaemia may thus play an important role in the decline in fertility in addition to other environmental or lifestyle factors. The objective of this population based cohort study was to evaluate the association between men's serum lipid concentrations and semen quality parameters among 501 male partners of couples desiring pregnancy and discontinuing contraception. Each participant provided prospectively up to two semen samples (94% of men provided one or more semen samples, and 77% of men provided a second sample approximately 1 month later). Linear mixed effects models were used to estimate the associations between baseline lipid concentrations and semen quality parameters, adjusted for age, body mass index and race. We found that higher levels of serum total cholesterol, free cholesterol and phospholipids were associated with a significantly lower percentage of spermatozoa with intact acrosome and smaller sperm head area and perimeter. Our results suggest that lipid concentrations may affect semen parameters, specifically sperm head morphology, highlighting the importance of cholesterol and lipid homeostasis for male fecundity.

Multicenter study to assess potential hazards from exposure to lipid peroxidation products in soya bean oil from Trilucent breast implants.

In response to a Hazard Notice by the Medical Devices Agency of the UK in 2000 regarding the Trilucent breast implant (TBI), an expert panel was convened to implement a research program to determine whether genotoxic compounds were formed in the soybean oil filler (SOF) of TBIs and whether these could be released to produce local or systemic genotoxicity. The panel established a research program involving six laboratories. The program recruited 47 patients who had received TBIs (9 patients had received silicone implants previously). A reference group (REBI) of 34 patients who had exchanged either silicone (17 patients) implants (REBI-E) or patients (17) who were to receive primary implantation augmentation with silicone (REBI-PIA), and who were included as needed to increase either the pre- or post-explantation sample number. Of the 17 REBI-E patients, 5 had silicone implants and 12 had saline implants previously (prior to the last exchange). Investigation was undertaken before and after replacement surgery in the TBI patients and before and after replacement or augmentation surgery in the REBI patients. The pre- to post-operative sample interval was 8-12 weeks. Pre-operative samples were collected within 7 days prior to the operation. Information on a variety of demographic and behavioral features was collected. Biochemical and biological endpoints relating to genotoxic lipid peroxidation (LPO) products potentially formed in the SOF, and released locally or distributed systemically, were measured. The SOF of explanted TBIs was found to have substantial levels of LPO products, particularly malondialdehyde (MDA), and low levels of trans-4-hydroxy-2-nonenal (HNE) not found in unused implants. Mutagenicity of the SOF was related to the levels of MDA. Capsules that formed around TBIs were microscopically similar to those of reference implants, but MDA-DNA adducts were observed in capsular macrophages and fibroblasts of only TBI capsules. These cell types are not progenitors of breast carcinoma (BCa) and the location of the implants precludes LPO products reaching the mammary epithelial cells which are progenitors of BCa. Blood levels of LPO products were not increased in TBI patients compared to REBI patients and did not change with explantation. In TBI patients, white blood cells did not show evidence of increased levels of LPO-related aldehyde DNA adducts. In conclusion, based on a number of measured parameters, there was no evident effect that would contribute to breast or systemic cancer risk in the TBI patients, and the recommended treatment of TBI patients involving explantation was judged appropriate.

Distributions of high-density lipoprotein particle components in human follicular fluid and sera and their associations with embryo morphology parameters during IVF.

BACKGROUND: High-density lipoprotein (HDL) is the sole lipoprotein present in follicular fluid (FF). The objectives of this study were to examine HDL lipid composition and associated enzyme activities in FF and serum and to relate these levels to embryo morphology parameters in women undergoing in vitro fertilization (IVF). METHODS: Serum and FF were prospectively obtained from 60 women undergoing IVF. HDL lipids, apolipoprotein AI (ApoAI), paraoxonase 1 (PON1) and paraoxonase 3 (PON3) activities were determined. Bivariate analysis and ordinal logistic regression models were employed to examine the associations between biochemical measures and embryo morphology parameters [embryo cell number (ECN) and embryo fragmentation score (EFS)] as surrogate markers of oocyte health. RESULTS: All biochemical parameters were significantly (P < 0.05) lower in FF than serum except PON3 levels which were significantly higher. FF-HDL cholesterol (OR 0.66, 95%CI 0.46-0.96) and ApoAI (OR 0.13, 95%CI 0.03-0.97) levels were negative predictors for EFS; however, their effects were not independent and the level of one moderated the effect of the other. Limited to Day 3 embryo transfers, FF-PON1-arylesterase activity was a significant positive predictor for ECN (OR 1.09, 95%CI 1.01-1.17). CONCLUSIONS: In this pilot study, our data suggests that HDL and its component proteins within FF may play protective roles in the health of the human oocyte and subsequent early embryo development. We describe for the first time the activities of PON1 and PON3 in FF. We suspect that PON3 activity may be locally generated due to higher activities in FF compared with serum.

Antioxidants, oxidative stress, and pulmonary function in individuals diagnosed with asthma or COPD.

OBJECTIVE: The objective of this study was to investigate the association between antioxidant nutrients and markers of oxidative stress with pulmonary function in persons with chronic airflow limitation. DESIGN: Cross-sectional study exploring the association of antioxidant nutrients and markers of oxidative stress with forced expiratory volume in the first second (FEV1%) and forced vital capacity (FVC%). SETTING/SUBJECTS: The study data included 218 persons with chronic airflow limitation recruited randomly from the general population of Erie and Niagara counties, New York State, USA. RESULTS: After adjustment for covariates, multiple linear regression analysis showed that serum beta-cryptoxanthin, lutein/zeaxanthin, and retinol, and dietary beta-carotene, beta-cryptoxanthin, lutein/zeaxanthin, vitamin C, and lycopene were positively associated with FEV1% (P < 0.05, all associations). Serum vitamins beta-cryptoxanthin, lutein/zeaxanthin, and lycopene, and dietary beta-cryptoxanthin, beta-carotene, vitamin C, and lutein/zeaxanthin were positively associated with FVC% (P < 0.05, all associations). Erythrocytic glutathione was negatively associated with FEV1%, while plasma thiobarbituric acid-reactive substances (TBARS) were negatively associated with FVC% (P < 0.05). CONCLUSION: These results support the hypothesis that an imbalance in antioxidant/oxidant status is associated with chronic airflow limitation, and that dietary habits and/or oxidative stress play contributing roles.

The relation of serum levels of antioxidant vitamins C and E, retinol and carotenoids with pulmonary function in the general population.

Reduced pulmonary function is an important predictor of mortality in the general population, and antioxidant vitamins are thought to positively influence pulmonary function. Vitamin C, vitamin E, retinol, and carotenoids are powerful antioxidants but information about the joint relation of serum levels of these antioxidants to pulmonary function is limited. We analyzed the association of FEV(1) and FVC with serum vitamins C and E, retinol, and carotenoids (beta-cryptoxanthin, lutein/zeaxanthin, beta-carotene, and lycopene) in a cross-sectional study. The analysis was carried out in a sample of 1,616 randomly selected residents of Western New York, USA, age 35 to 79 yr and free of respiratory disease. Lung function was adjusted for height, age, sex, and race and expressed as percentage of predicted normal FEV(1) (FEV(1)%) and FVC (FVC%). Participants in the lowest quartile of each of the serum antioxidants had consistently lower FEV(1)% and FVC% than those in higher quartiles. Multiple linear regression analysis revealed significant associations of vitamin C, vitamin E, beta-cryptoxanthin, lutein/zeaxanthin, beta-carotene, and retinol with FEV(1)% when these variables were investigated individually after adjustment for other covariates (smoking status, pack-years of smoking, weight, eosinophil count, and education). When all of these antioxidant vitamins were analyzed simultaneously in a multivariate regression model, the strongest association was seen with vitamin E and beta-cryptoxanthin. Only retinol showed an independent effect on FEV(1)% after controlling for vitamin E and beta-cryptoxanthin. As for FEV(1)%, vitamin E and beta-cryptoxanthin were most strongly related to FVC% when all variables were considered in the multivariate regression model. The differences in FEV(1) associated with a reduction of one standard deviation of serum vitamin E or beta-cryptoxanthin were equivalent to the negative influence of approximately 1 to 2 yr of aging. Our findings support the hypothesis that antioxidant vitamins may play a role in respiratory health and that vitamin E and beta-cryptoxanthin appear to be stronger correlates of lung function than other antioxidant vitamins.

Manganese-induced rat pheochromocytoma (PC12) cell death is independent of caspase activation.

Manganese (Mn) is an essential mineral that at high concentrations can produce an irreversible syndrome resembling Parkinson's disease. To examine the mechanism by which Mn elicits its toxic response, we have selected the rat pheochromocytoma cells (PC12) as our model system because it possesses much of the biochemical machinery associated with dopaminergic neurons. Mn-induced PC12 cell death is both time and concentration dependent with approximately 50% cell survival at 48 hr in the presence of 0.3 mM Mn. To determine whether oxidative stress contributed to cytotoxicity induced by Mn, lipid peroxidation was assessed in Mn-treated in PC12 cells. The highly sensitive HPLC assay that measures the lipid peroxide product, 9-HODE, was used and results of these experiments demonstrate there was no increase in the lipid peroxidation in cells exposed to 0.3 mM Mn for 24 hr. Mn was found to stimulate the activation of the apoptotic marker proteins, p38 and caspase-3 within the first 24 hr of treatment. The selective inhibitor of caspase-3, DEVD-CHO, and the nonselective caspase inhibitor, Z-VAD-FMK, however, fail to prevent Mn-induced PC12 cell death. Studies were performed to determine the role of mitochondria in initiating or supporting Mn cytotoxicity, because Mn has been reported to cause changes in membrane permeability. Mn caused a decrease in ATP levels in PC12 cells in both a time and concentration dependent manner. We hypothesize that both apoptosis and necrosis contribute to PC12 cell death although the necrotic events prevail even when the apoptotic signaling is inhibited.

HPLC analysis of lipid-derived polyunsaturated fatty acid peroxidation products in oxidatively modified human plasma.

BACKGROUND: Lipid peroxidation is a prominent manifestation of free radical activity and oxidative stress in biological systems. Diverse methodologies have been developed that measure a variety of lipid peroxidation products used as markers of lipid peroxidation processes. METHODS: Hydroxy and hydroperoxy polyunsaturated fatty acid (PUFA) peroxidation products were analyzed in human blood plasma by reversed-phase HPLC after liquid-liquid extraction of total lipids and alkaline hydrolysis of lipid esters to liberate free PUFAs. An isocratic mobile phase containing 1 g/L acetic acid-acetonitrile-tetrahydrofuran (52:30:18, by volume) over 60 min duration, with ultraviolet absorbance detection at 236 nm by photodiode array, enabled the resolution and quantification of 13 regioisomeric hydroxy and hydroperoxy PUFAs. RESULTS: As little as 250 microL of human plasma was utilized with an analytical range of 0.033-1.6 micromol/L for each compound. Intra- and interassay CVs for all compounds detected in normal or oxidatively modified human plasma were 3.2-11% and 4.7-12%, respectively. Analytical recoveries were 87-103%. Analysis of human plasma exposed to artificial oxidation with Cu(2+) ion and hydrogen peroxide, a free radical-generating reaction, showed marked increases in hydroxy and hydroperoxy PUFA concentrations. CONCLUSION: Lipid-derived hydroxy and hydroperoxy PUFAs may be useful as clinical markers of lipid peroxidation and oxidative stress in the peripheral circulation.

Serum markers of oxidative stress and severity of diabetic retinopathy.

OBJECTIVE: To compare serum markers of oxidative stress with diabetic retinopathy severity RESEARCH DESIGN AND METHODS: This cross-sectional study compared patients with types 1 and 2 diabetes with control subjects in western New York and Pennsylvania. Retinopathy severity was graded from funduscopic fields based on the Early Treatment of Diabetic Retinopathy Study. Serum samples were analyzed for thiobarbituric acid-reacting substances (TBARS), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities, creatinine, HbA1, and triglycerides. Appropriate analysis of covariance models were performed. RESULTS: TBARS (P = 0.019), triglyceride (P = 0.004), and glucose and HbA1 (both P<0.001) levels were elevated in diabetic patients compared with those in control subjects. SOD (P = 0.003) and GSH-Px (P = 0.046) levels were lower in diabetic patients than in control subjects. No correlation existed between SOD levels and either glucose or HbA1 levels. No significant associations existed between levels of TBARS, SOD, or GSH-Px and severity of diabetic retinopathy There was a significant association between poorer visual acuity and worse retinopathy (P = 0.009), which was only partly explained by macular edema. CONCLUSIONS: Increased levels of TBARS and decreased levels of SOD and GSH-Px were found in diabetic patients compared with those in control subjects, but no significant associations were found between the levels of these substances and severity of retinopathy When duration and type of diabetes and serum HbA1 levels were taken into account, only visual acuity remained associated with more severe retinopathy.

Effects of transportation and delay in processing on the stability of nutritional and metabolic biomarkers.

The effects of transportation and delay in processing of blood samples on the concentration of biomarkers are significant in epidemiological studies for which specimens are collected from participants at locations other than a designated center or laboratory. These sources of variability in measurement were studied by collecting two sets of blood samples from 51 men between 26 and 50 years of age. The first set was sent immediately to the laboratory for processing. The second set was transported by car for one hour and then returned to the laboratory for processing. Both sets were stored together at -80 degrees C until the end of the study. Several blood constituents were evaluated. Vitamins, liver enzymes, and electrolytes showed no changes in concentration after transport by car for one hour. There were decreases in the concentrations of red and white blood cells, high-density-lipoprotein cholesterol, glucose, and creatinine after transportation. The transported total cholesterol, total testosterone, free testosterone, alkaline phosphatase, total bilirubin, and thiobarbituric acid-reactive substances increased in concentration. Although transportation and delay in processing of blood samples do not appear to greatly impact relative risk estimates, epidemiologists should be aware of these potential sources of variability in measurement and consider the consequences in their particular study.

Characterization of peroxidized lipids in Bruch's membrane.

PURPOSE: To determine if peroxidized lipids occur in Bruch's membrane isolates and to characterize the type present in human necropsy specimens. METHODS: Bruch's membrane isolates from eye bank eyes obtained from 13 white donors were homogenized. Measurement of peroxidized lipids was done with the fluorometric thiobarbituric acid assay and high pressure liquid chromatography. RESULTS: Bruch's membrane isolate homogenates contained native unsaturated fatty acids and peroxidized lipids in a ratio of about 200:1. The amount of thiobarbituric acid reacting substances increased exponentially with age. The peroxidized lipids identified in Bruch's membrane isolates were derived from long chain polyunsaturated fatty acids, particularly docosahexaenoic acid and linolenic acid, which are normally found in the photoreceptor outer segments. CONCLUSIONS: Lipids are known to accumulate in Bruch's membrane, an acellular layer with no known intrinsic mechanisms to combat lipid peroxidation. In related studies, lipid peroxides have been shown to induce neovascularization by inducing expression of a cascade of angiogenic cytokines. This is the first study to show that lipid peroxides, biological molecules that have the potential to incite new vessel growth, occur in Bruch's membrane. The increase in amount of peroxidized lipids with age, combined with their vasogenic potential, suggests that peroxidized lipids may play a role in the etiology of age-related macular degeneration, particularly choroidal neovascularization.