Lipid profiles for antiretroviral-naive patients starting PI- and NNRTI-based therapy in the Swiss HIV cohort study

BACKGROUND: Blood lipid abnormalities in patients on highly active antiretroviral therapy (HAART) have been associated with exposure to protease inhibitors (PIs), particularly ritonavir. First therapy with a non-nucleoside reverse transcriptase inhibitor (NNRTI) leads to relatively favourable lipid profiles. We report on medium-term lipid profiles (up to 5 years) for antiretroviral-naive patients starting NNRTI- and PI-based HAART in the Swiss HIV Cohort Study. METHODS: Since April 2000, blood samples taken at visits scheduled every 6 months have been analysed for cholesterol and triglyceride concentrations. For 1065 antiretroviral-naive patients starting HAART after April 2000, we estimated changes in concentration over time using multivariate linear regression with adjustment for baseline covariates, use of lipid-lowering drugs and whether the sample was taken in a fasting state. RESULTS: Non-high density lipoprotein (HDL) cholesterol levels increase with increasing exposure to either PI- or NNRTI-based therapy, HDL cholesterol levels increase and triglyceride levels decrease with increasing exposure to NNRTI-based therapy, whereas triglyceride levels increase with increasing exposure to PI-based therapy. Between NNRTI-based therapies, there is a slight difference in triglyceride levels, which tend to increase with increasing exposure to efavirenz and to decrease with increasing exposure to nevirapine. Of the three common PI-based therapies, nelfinavir appears to have a relatively favourable lipid profile, with little change with increasing exposure. Of the other two PI therapies, lopinavir with ritonavir has a more favourable profile than indinavir with ritonavir, with smaller increases in both non-HDL cholesterol and triglycerides and an increase in HDL cholesterol. Increasing exposure to abacavir is associated with a decrease in the level of triglycerides. CONCLUSION: In general, NNRTI-based therapy is associated with a more favourable lipid profile than PI-based therapy, but different PI-based therapies are associated with very different lipid profiles. Nelfinavir appears to have a relatively favourable lipid profile. Of the two boosted PI therapies, lopinavir appears to have a more favourable lipid profile than indinavir.

Association of biomarkers of lipid modification with functional and morphological indices of coronary stenosis severity in stable coronary artery disease

Biomarkers of blood lipid modification and oxidative stress have been associated with increased cardiovascular morbidity. We sought to determine whether these biomarkers were related to functional indices of stenosis severity among patients with stable coronary artery disease. We studied 197 consecutive patients with stable coronary artery disease due to single vessel disease. Fractional flow reserve (FFR) ≤ 0.80 was assessed as index of a functionally significant lesion. Serum levels of secretory phospholipase A2 (sPLA2) activity, secretory phospholipase A2 type IIA (sPLA2-IIA), myeloperoxydase (MPO), lipoprotein-associated phospholipase A2 (Lp-PLA2), and oxidized low-density lipoprotein (OxLDL) were assessed using commercially available assays. Patients with FFR > 0.8 had higher sPLA2 activity, sPLA2 IIA, and OxLDL levels than patients with FFR ≤ 0.8 (21.25 [16.03-27.28] vs 25.85 [20.58-34.63] U/mL, p < 0.001, 2.0 [1.5-3.4] vs 2.6 [2.0-3.4] ng/mL, p < 0.01; and 53.0 [36.0-71.0] vs 64.5 [50-89.25], p < 0.001 respectively). Patients with FFR > 0.80 had similar Lp-PLA2 and MPO levels versus those with FFR ≤ 0.8. sPLA2 activity, sPLA2 IIA significantly increased area under the curve over baseline characteristics to predict FFR ≤ 0.8 (0.67 to 0.77 (95 % confidence interval [CI]: 0.69-0.85) p < 0.01 and 0.67 to 0.77 (95 % CI: 0.69-0.84) p < 0.01, respectively). Serum sPLA2 activity as well as sPLA2-IIA level is related to functional characteristics of coronary stenoses in patients with stable coronary artery disease.

A randomized cross-over study to compare raltegravir and efavirenz (SWITCH-ER study)

Efavirenz (EFV) causes neuropsychiatric side-effects and an unfavorable blood lipid profile. We investigated the effect of replacing EFV with raltegravir (RAL) on patient preference, daytime sleepiness, sleep quality, anxiety, and lipid levels.

A randomized crossover study to compare efavirenz and etravirine treatment

Efavirenz (EFV) causes neuropsychiatric side-effects and an unfavourable blood lipid profile. We investigated the effect of replacing EFV with etravirine (ETR) on patient preference, sleep, anxiety and lipid levels.

Protein and lipid binding parameters in rainbow trout (Oncorhynchus mykiss) blood and liver fractions to extrapolate from an in vitro metabolic degradation assay to in vivo bioaccumulation potential of hydrophobic organic chemicals

Binding of hydrophobic chemicals to colloids such as proteins or lipids is difficult to measure using classical microdialysis methods due to low aqueous concentrations, adsorption to dialysis membranes and test vessels, and slow kinetics of equilibration. Here, we employed a three-phase partitioning system where silicone (polydimethylsiloxane, PDMS) serves as a third phase to determine partitioning between water and colloids and acts at the same time as a dosing device for hydrophobic chemicals. The applicability of this method was demonstrated with bovine serum albumin (BSA). Measured binding constants (K(BSAw)) for chlorpyrifos, methoxychlor, nonylphenol, and pyrene were in good agreement with an established quantitative structure-activity relationship (QSAR). A fifth compound, fluoxypyr-methyl-heptyl ester, was excluded from the analysis because of apparent abiotic degradation. The PDMS depletion method was then used to determine partition coefficients for test chemicals in rainbow trout (Oncorhynchus mykiss) liver S9 fractions (K(S9w)) and blood plasma (K(bloodw)). Measured K(S9w) and K(bloodw) values were consistent with predictions obtained using a mass-balance model that employs the octanol-water partition coefficient (K(ow)) as a surrogate for lipid partitioning and K(BSAw) to represent protein binding. For each compound, K(bloodw) was substantially greater than K(S9w), primarily because blood contains more lipid than liver S9 fractions (1.84% of wet weight vs 0.051%). Measured liver S9 and blood plasma binding parameters were subsequently implemented in an in vitro to in vivo extrapolation model to link the in vitro liver S9 metabolic degradation assay to in vivo metabolism in fish. Apparent volumes of distribution (V(d)) calculated from the experimental data were similar to literature estimates. However, the calculated binding ratios (f(u)) used to relate in vitro metabolic clearance to clearance by the intact liver were 10 to 100 times lower than values used in previous modeling efforts. Bioconcentration factors (BCF) predicted using the experimental binding data were substantially higher than the predicted values obtained in earlier studies and correlated poorly with measured BCF values in fish. One possible explanation for this finding is that chemicals bound to proteins can desorb rapidly and thus contribute to metabolic turnover of the chemicals. This hypothesis remains to be investigated in future studies, ideally with chemicals of higher hydrophobicity.

Functions of lipid raft membrane microdomains at the blood-brain barrier

The blood-brain barrier (BBB) is a highly specialized structural and functional component of the central nervous system that separates the circulating blood from the brain and spinal cord parenchyma. Brain endothelial cells (BECs) that primarily constitute the BBB are tightly interconnected by multiprotein complexes, the adherens junctions and the tight junctions, thereby creating a highly restrictive cellular barrier. Lipid-enriched membrane microdomain compartmentalization is an inherent property of BECs and allows for the apicobasal polarity of brain endothelium, temporal and spatial coordination of cell signaling events, and actin remodeling. In this manuscript, we review the role of membrane microdomains, in particular lipid rafts, in the BBB under physiological conditions and during leukocyte transmigration/diapedesis. Furthermore, we propose a classification of endothelial membrane microdomains based on their function, or at least on the function ascribed to the molecules included in such heterogeneous rafts: (1) rafts associated with interendothelial junctions and adhesion of BECs to basal lamina (scaffolding rafts); (2) rafts involved in immune cell adhesion and migration across brain endothelium (adhesion rafts); (3) rafts associated with transendothelial transport of nutrients and ions (transporter rafts).

Current cardiovascular risk management patterns with special focus on lipid lowering in daily practice in Switzerland

There may be a considerable gap between LDL cholesterol (LDL-C) and blood pressure (BP) goal values recommended by the guidelines and results achieved in daily practice.

Lipid and lipoprotein profile in HIV-infected patients treated with lopinavir/ritonavir as a component of the first combination antiretroviral therapy

We characterized lipid and lipoprotein changes associated with a lopinavir/ritonavir-containing regimen. We enrolled previously antiretroviral-naive patients participating in the Swiss HIV Cohort Study. Fasting blood samples (baseline) were retrieved retrospectively from stored frozen plasma and posttreatment (follow-up) samples were collected prospectively at two separate visits. Lipids and lipoproteins were analyzed at a single reference laboratory. Sixty-five patients had two posttreatment lipid profile measurements and nine had only one. Most of the measured lipids and lipoprotein plasma concentrations increased on lopinavir/ritonavir-based treatment. The percentage of patients with hypertriglyceridemia (TG >150?mg/dl) increased from 28/74 (38%) at baseline to 37/65 (57%) at the second follow-up. We did not find any correlation between lopinavir plasma levels and the concentration of triglycerides. There was weak evidence of an increase in small dense LDL-apoB during the first year of treatment but not beyond 1 year (odds ratio 4.5, 90% CI 0.7 to 29 and 0.9, 90% CI 0.5 to 1.5, respectively). However, 69% of our patients still had undetectable small dense LDL-apoB levels while on treatment. LDL-cholesterol increased by a mean of 17?mg/dl (90% CI -3 to 37) during the first year of treatment, but mean values remained below the cut-off for therapeutic intervention. Despite an increase in the majority of measured lipids and lipoproteins particularly in the first year after initiation, we could not detect an obvious increase of cardiovascular risk resulting from the observed lipid changes.

Maternal and fetal cord blood lipids in intrauterine growth restriction

Small for gestational age neonates (SGA) could be subdivided into two groups according to the underlying causes leading to low birth weight. Intrauterine growth restriction (IUGR) is a pathologic condition with diminished growth velocity and fetal compromised well-being, while non-growth restricted SGA neonates are constitutionally (genetically determined) small. Antenatal sonographic measurements are used to differentiate these two subgroups. Maternal metabolic changes contribute to the pathogenesis of IUGR. A disturbed lipid metabolism and cholesterol supply might affect the fetus, with consequences for fetal programming of cardiovascular diseases. We evaluated fetal serum lipids and hypothesized a more atherogenic lipoprotein profile in IUGR fetuses.

Posttranscriptional regulation of Fas (CD95) ligand killing activity by lipid rafts

Fas (CD95/Apo-1) ligand-mediated apoptosis induction of target cells is one of the major effector mechanisms by which cytotoxic lymphocytes (T cells and natural killer cells) kill their target cells. In T cells, Fas ligand expression is tightly regulated at a transcriptional level through the activation of a distinct set of transcription factors. Increasing evidence, however, supports an important role for posttranscriptional regulation of Fas ligand expression and activity. Lipid rafts are cholesterol- and sphingolipid-rich membrane microdomains, critically involved in the regulation of membrane receptor signaling complexes through the clustering and concentration of signaling molecules. Here, we now provide evidence that Fas ligand is constitutively localized in lipid rafts of FasL transfectants and primary T cells. Importantly, disruption of lipid rafts strongly reduces the apoptosis-inducing activity of Fas ligand. Localization to lipid rafts appears to be predominantly mediated by the characteristic cytoplasmic proline-rich domain of Fas ligand because mutations of this domain result in reduced recruitment to lipid rafts and attenuated Fas ligand killing activity. We conclude that Fas ligand clustering in lipid rafts represents an important control mechanism in the regulation of T cell-mediated cytotoxicity.

Equine peripheral blood-derived progenitors in comparison to bone marrow-derived mesenchymal stem cells

Fibroblast-like cells isolated from peripheral blood of human, canine, guinea pig, and rat have been demonstrated to possess the capacity to differentiate into several mesenchymal lineages. The aim of this work was to investigate the possibility of isolating pluripotent precursor cells from equine peripheral blood and compare them with equine bone marrow-derived mesenchymal stem cells. Human mesenchymal stem cells (MSCs) were used as a control for cell multipotency assessment. Venous blood (n = 33) and bone marrow (n = 5) were obtained from adult horses. Mononuclear cells were obtained by Ficoll gradient centrifugation and cultured in monolayer, and adherent fibroblast-like cells were tested for their differentiation potential. Chondrogenic differentiation was performed in serum-free medium in pellet cultures as a three-dimensional model, whereas osteogenic and adipogenic differentiation were induced in monolayer culture. Evidence for differentiation was made via biochemical, histological, and reverse transcription-polymerase chain reaction evaluations. Fibroblast-like cells were observed on day 10 in 12 out of 33 samples and were allowed to proliferate until confluence. Equine peripheral blood-derived cells had osteogenic and adipogenic differentiation capacities comparable to cells derived from bone marrow. Both cell types showed a limited capacity to produce lipid droplets compared to human MSCs. This result may be due to the assay conditions, which are established for human MSCs from bone marrow and may not be optimal for equine progenitor cells. Bone marrow-derived equine and human MSCs could be induced to develop cartilage, whereas equine peripheral blood progenitors did not show any capacity to produce cartilage at the histological level. In conclusion, equine peripheral blood-derived fibroblast-like cells can differentiate into distinct mesenchymal lineages but have less multipotency than bone marrow-derived MSCs under the conditions used in this study.

Multilineage differentiation potential of equine blood-derived fibroblast-like cells

Tissue engineering (TE) has emerged as a promising new therapy for the treatment of damaged tissues and organs. Adult stem cells are considered as an attractive candidate cell type for cell-based TE. Mesenchymal stem cells (MSC) have been isolated from a variety of tissues and tested for differentiation into different cell lineages. While clinical trials still await the use of human MSC, horse tendon injuries are already being treated with autologous bone marrow-derived MSC. Given that the bone marrow is not an optimal source for MSC due to the painful and risk-containing sampling procedure, isolation of stem cells from peripheral blood would bring an attractive alternative. Adherent fibroblast-like cells have been previously isolated from equine peripheral blood. However, their responses to the differentiation conditions, established for human bone marrow MSC, were insufficient to fully confirm their multilineage potential. In this study, differentiation conditions were optimized to better evaluate the multilineage capacities of equine peripheral blood-derived fibroblast-like cells (ePB-FLC) into adipogenic, osteogenic, and chondrogenic pathways. Adipogenic differentiation using rabbit serum resulted in a high number of large-size lipid droplets three days upon induction. Cells' expression of alkaline phosphatase and calcium deposition upon osteogenic induction confirmed their osteogenic differentiation capacities. Moreover, an increase of dexamethasone concentration resulted in faster osteogenic differentiation and matrix mineralization. Finally, induction of chondrogenesis in pellet cultures resulted in an increase in cartilage-specific gene expression, namely collagen II and aggrecan, followed by protein deposition after a longer induction period. This study therefore demonstrates that ePB-FLC have the potential to differentiate into adipogenic, osteogenic, and chondrogenic mesenchymal lineages. The presence of cells with confirmed multilineage capacities in peripheral blood has important clinical implications for cell-based TE therapies in horses.

Oxidative stress and damage in liver, but not in brain, of Fischer 344 rats subjected to dietary iron supplementation with lipid-soluble [(3,5,5-trimethylhexanoyl)ferrocene]

Accumulation of iron probably predisposes the aging brain to progressive neuronal loss. We examined various markers of oxidative stress and damage in the brain and liver of 3- and 24-month-old rats following supplementation with the lipophilic iron derivative [(3,5,5-trimethylhexanoyl)ferrocene] (TMHF), which is capable of crossing the blood-brain barrier. At both ages, iron concentration increased markedly in the liver but failed to increase in the brain. In the liver of TMHF-treated young rats, levels of alpha- and gamma-tocopherols and glutathione (GSH) were also higher. In contrast, the brain displayed unaltered levels of the tocopherols and GSH. Malondialdehyde (MDA) level was also higher in the cerebrospinal fluid (CSF) and the liver but not in the brain. In old rats, the absence of an increase in iron concentration in the brain was reflected by unaltered concentrations of GSH, tocopherols, and MDA as compared to that in untreated rats. In the aging liver, concentrations of GSH and MDA increased with TMHF treatment. Morphological studies revealed unaltered levels of iron, ferritin, heme oxygenase-1 (HO-1), nitrotyrosine (NT), or MDA in the brains of both young and old rats treated with TMHF. In contrast, TMHF treatment increased the level of HO-1 in Kupffer cells, NT in hepatic endothelial cells, and MDA and ferritin in hepatocytes. Although these results demonstrated an increase in the biochemical markers of oxidative stress and damage in response to increasing concentrations of iron in the liver, they also demonstrated that the brain is well protected against dietary iron overload by using iron in a lipid-soluble formulation.

Differential expression and localization of lipid transporters in the bovine mammary gland during the pregnancy-lactation cycle

The transport of lipids across mammary gland epithelial cells (MEC) determines milk lipid content and composition. We investigated the expression of lipid transporters and their regulators in comparison to blood metabolites during lactation and dry period (DP) in dairy cows. Repeated mammary gland biopsies and blood samples were taken from 10 animals at 7 stages of the pregnancy-lactation cycle. Expression levels of the specific mRNAs were determined by quantitative reverse transcription-PCR, whereas ABCA1 was localized by immunohistochemistry. Blood serum metabolites were determined by common enzymatic chemistries. Elevated mRNA profiles of ABCA1 and ABCA7 were found during DP as compared with lactation and were inversely associated with blood cholesterol levels. Elevated levels of ABCG2, NPC1, SREBP1, SREBP2, LXR alpha, and PPAR gamma were found postpartum, whereas ABCG1 did not differ between the functional stages of the mammary gland. The ABCA1 protein was localized in MEC and showed differential activity between DP and lactation suggesting a role of ABCA1 in the removal of excess cellular cholesterol from MEC during the DP. The expression profiles of ABCA7 and NPC1 may reflect a role of these transporters in the clearance of apoptotic cells and the intracellular redistribution of cholesterol, respectively. Regulation of lipid transporters in the mammary gland is partially associated with transcription factors that control lipid homeostasis.