Chronic hyperplastic anemia as an independent risk factor for atherosclerotic lesions: a lesson from thalassemia intermedia

Introduction. Cardiovascular involvement represents a well-known complication and the primary cause of mortality, both in transfusion-dependent beta thalassemia major (β-TM) and in transfusion-independent beta thalassemia intermedia (β-TI). In β-TM, heart iron overload is considered the main cause of this complication. This is likely due to poor adherence to iron-chelating therapy, resulting in the inability of the body to efficiently remove iron excess derived from transfused red blood cell breakdown. Different clinical pictures may instead be evoked in cardiovascular involvement occurring in β-TI; however, until now, no factor has emerged as the major one responsible for these complications. 
Design and Methods. In the present study, iron status, and lipid profiles in serum, as well as lipid content in peripheral blood mononuclear cells (PBMCs) were evaluated in 70 adult β-TM and in 22 adult β-TI patients. Ninety-two age-matched blood donors, free from any form of thalassemia, were utilized as controls. The mRNA levels of genes involved in the regulation of iron metabolism, such as interleukine 1 alfa (IL1α), tumor necrosis factor alfa (TNFα), as well as those involved in cholesterol homeostasis, such as acetyl-coenzymeA: cholesterol acyltransferase (ACAT-1), neutral cholesterol ester hydrolase (nCEH), and ATP binding cassette-A (ABCA1), were also evaluated in PBMCs from the above subjects.
Results. In β-TI patients, serum iron, transferrin saturation and erythropoietin levels were higher, while transferrin and hepcidin were lower, compared to both β-TM and controls. Hepcidin and ILα mRNA levels were found to be reduced in β-TI-PBMCs, while those of TNFα were increased. A reduction in total and high density lipoprotein cholesterol (TC and HDL-C) in serum, and an accumulation of neutral lipids (NL), coupled with increased mRNA levels of ACAT-1 and decreased nCEH in PBMCs were also observed in β-TI. 
Conclusions. Since most of the parameters found to be altered in β-TI patients have a key role in the initiation and progression of atherosclerosis, we suggest that cardiovascular complications in these patients may be, at least partially, dependent on the occurrence of premature atherosclerotic lesions. 
&#xa

Altered cholesterol ester cycle in ex vivo skin fibroblasts from Alzheimer patients

Recent studies in both animal and cell models of Alzheimer's disease (AD) indicated that sub-cellular cholesterol distribution seems to regulate amyloid-beta (A[beta]) generation in the brain. In particular, cholesterol-esters (CE), rather than total cholesterol levels, appear directly correlated with A[beta] production. Here we observed that, similarly to brain cells, skin fibroblasts obtained from AD patients produce and accumulate more CE than skin fibroblasts from age-matched healthy controls do. AD fibroblasts also exhibited a 2 fold increase in the expression of ACAT1, in addition to lower levels of SREBP2, nCEH, Caveolin-1 and ABCA1 mRNA levels, all of which are involved in the CE cycle. HMGCoA-reductase and LDL-receptor mRNAs levels did not show statistically significant changes in AD, compared to non-AD, cells. Furthermore, although APP mRNA did not significantly vary, neprilysin (NEP), the most important enzyme in the proteolysis of A[beta], was expressed at very low levels in skin fibroblasts of sporadic AD patients. Our results contribute to the concept that AD may be the consequence of a basic and systemic defect in the CE cycle. Moreover, our results identify new possible targets for the diagnosis, prevention, and cure or, at least, amelioration of the symptoms of AD

accumulation of cholesterol esters in ex vivo lymphocytes from scrapie susceptible sheep and in scrapie infected mouse neuroblastoma cell lines

Our studies on the role of cholesterol homeostasis in the pathogenesis of scrapie in sheep, revealed abnormal accumulation of cholesterol esters in brains and in ex vivo skin fibroblasts from genetically scrapie-susceptible, as compared to sheep with resistant genotype. We now report that PBMCs isolated from scrapie-susceptible sheep, as well as mouse neuroblastoma cell lines persistently infected with two different mouse-adapted strains of scrapie, showed similar alterations with up to 3-fold higher cholesterol ester levels than their resistant or uninfected counterparts. Treatments with drugs that interfere with intracellular cholesterol metabolism strongly reduced accumulation of cholesterol esters in scrapie-infected cell lines, whereas had significantly lower, or no effect, in uninfected cell line. These data add support to our hypothesis that accumulation of cholesterol esters may represent a biological marker of susceptibility to prion infection and a potential molecular target for prion inhibitors

Accumulation of neutral lipids in peripheral blood mononuclear cells as a distinctive trait of Alzheimer patients and asymptomatic subjects at risk of disease

<p>Abstract</p> <p>Background</p> <p>Alzheimer's disease is the most common progressive neurodegenerative disease. In recent years, numerous progresses in the discovery of novel Alzheimer's disease molecular biomarkers in brain as well as in biological fluids have been made. Among them, those involving lipid metabolism are emerging as potential candidates. In particular, an accumulation of neutral lipids was recently found by us in skin fibroblasts from Alzheimer's disease patients. Therefore, with the aim to assess whether peripheral alterations in cholesterol homeostasis might be relevant in Alzheimer's disease development and progression, in the present study we analyzed lipid metabolism in plasma and peripheral blood mononuclear cells from Alzheimer's disease patients and from their first-degree relatives.</p> <p>Methods</p> <p>Blood samples were obtained from 93 patients with probable Alzheimer's disease and from 91 of their first-degree relatives. As controls we utilized 57, cognitively normal, over-65 year-old volunteers and 113 blood donors aged 21-66 years, respectively. Data are reported as mean ± standard error. Statistical calculations were performed using the statistical analysis software Origin 8.0 version. Data analysis was done using the Student t-test and the Pearson test.</p> <p>Results</p> <p>Data reported here show high neutral lipid levels and increased ACAT-1 protein in about 85% of peripheral blood mononuclear cells freshly isolated (<it>ex vivo</it>) from patients with probable sporadic Alzheimer's disease compared to about 7% of cognitively normal age-matched controls. A significant reduction in high density lipoprotein-cholesterol levels in plasma from Alzheimer's disease blood samples was also observed. Additionally, correlation analyses reveal a negative correlation between high density lipoprotein-cholesterol and cognitive capacity, as determined by Mini Mental State Examination, as well as between high density lipoprotein-cholesterol and neutral lipid accumulation. We observed great variability in the neutral lipid-peripheral blood mononuclear cells data and in plasma lipid analysis of the subjects enrolled as Alzheimer's disease-first-degree relatives. However, about 30% of them tend to display a peripheral metabolic cholesterol pattern similar to that exhibited by Alzheimer's disease patients.</p> <p>Conclusion</p> <p>We suggest that neutral lipid-peripheral blood mononuclear cells and plasma high density lipoprotein-cholesterol determinations might be of interest to outline a distinctive metabolic profile applying to both Alzheimer's disease patients and asymptomatic subjects at higher risk of disease.</p

Cholesterol Esterification During Differentiation by Hexamethylene Bisacetamide of Friend Virus-Induced Erythrokeukemia

AbstractCholesterol is an essential constituent of all mammalian cell membranes, and its availability is therefore a prerequisite for cellular growth and other functions. Several lines of evidence are now indicating an association between alterations of cholesterol homeostasis and cell cycle progression in cancer cells. However, the role of cholesterol in cell differentiation is still largely unknown. To begin to address this issue, in this study we examined changes in cholesterol metabolism and in the mRNA levels of proteins involved in cholesterol import and esterification (multi-drug resistance, MDR-3) and acylCoA:cholesterol acyltransferase (ACAT) and cholesterol export (caveolin-1) in Friend virus-induced erythroleukemia cells (MELC), in the absence or in the presence of the chemical inducer of differentiation, hexamethylene bisacetamide (HMBA). In uninduced MELC, cholesterol synthesis, esterification and MDR-3 and ACAT mRNAs increased as cells progressed from resting to proliferating phase, while caveolin-1 decreased. These results provide evidence that cholesterol esterification "per se" may have a role in cell division. When MELC are treated with HMBA, the reduction of DNA synthesis caused by the inducer is accompanied by an extensive decrease of cholesterol esterification and of ACAT and MDR-3 mRNA levels and by a significant increase in caveolin-1 mRNA. On the other hand, detection of cytoplasmic neutral lipids by staining MELC with oil-ORO, a dye able to evidence CE but not FC, revealed that HMBA-treatment inhibits cholesterol ester accumulation in MELC to approximately the same extent as the ACAT inhibitor, SaH. These results, other than, to add new insights on the possible role of cholesterol metabolism during tumor growth, for the first time indicate a possible involvement of cholesterol esterification pathways in the regulating of differentiation of erythroleukemic cells

Pharmacologic Cholesterol Homeostasis Affects Prion Generation in a Synergistic Manner

n/

Cell cholesterol esters and high-density lipoprotein plasma levels during liver hyperplasia in choline-fed male and female rats

Sexual dimorphism exists in the response of rats to lead nitrate, liver hyperplasia occuring earlier and being more pronounced in males. Excess dietary choline in females shifted the growth pattern towards that of males. To determine whether phosphatidylcholine-induced growth modulations could be related to a derangement of cholesterol metabolism, liver accumulation of cholesterol esters and plasma lipoprotein patterns were investigated. In males, lead-induced liver hyperplasia was associated with increased total cholesterol hepatic content, accumulated cholesterol esters and reduced concentration of plasma High Density Lipoprotein (HDL) cholesterol. Females were less responsive to the liver mitogenic signal of lead nitrate; there was no elevation of cholesterol content nor any marked accumulation of cholesterol esters. This is consistent with the lack of change in the plasma levels of HDL cholesterol. Continuous choline feeding displaced the liver cholesterol ester pattern and plasma HDL cholesterol levels in females, and in parallel that of DNA synthesis, towards those of males. Choline was not observed to have any effect in males. These results suggest that the derangement of phosphatidylcholine metabolism induces growth-related changes in cholesterol turnover; they are consistent with the proposal that the intracellular content of cholesterol esters may have a role in regulating liver growth rates