Background: Neurons need a high amount of cholesterol to maintain the stability of their membrane-rich structures. Astrocytes synthesize and distribute cholesterol to neurons, and ABCA1 is a key mediator of cholesterol efflux to generate HDL for cholesterol transport in the brain. Several studies imply the effect of aspirin on ABCA1 expression in peripheral cells such as macrophages. Here, we compared the effect of aspirin with apoA-I on ABCA1 protein expression and cholesterol efflux in human astrocytes. Materials and Methods: Human astrocytes were cultured, and the effects of aspirin on the expression and protein levels of ABCA1 were investigated through RT-PCR and Western blot analysis. Additionally, the effect of co-treatment with apoA-I and aspirin on ABCA1 protein level and cholesterol efflux was evaluated. Results: Dose and time-course experiments showed that the maximum effect of aspirin on ABCA1 expression occurred at a concentration of 0. 5 mM after 12 h of incubation. RT-PCR and western blot data showed that aspirin upregulates ABCA1 expression by up to 4. 7-fold and its protein level by 67%. Additionally, co-treatment with aspirin and apoA-I increased cholesterol release from astrocytes, indicating an additive effect of aspirin on apoAI-mediated cholesterol efflux. Conclusions: The results suggest a potential role of aspirin in increasing ABCA1 expression and cholesterol efflux in astrocytes, similar to the effect of apoA-I. This indicates that aspirin could potentially regulate brain cholesterol balance and can be considered in certain neurological diseases, in particular in some neurological disorders related to cholesterol accumulation such as Alzheimer’s disease.

Objective: Dysregulation of cholesterol metabolism in the brain is responsible for many lipid storage disorders, including Niemann-Pick disease type C (NPC). Here, we have investigated whether cyclodextrin (CD) and apolipoprotein A-I (apoA-I) induce the same signal to inhibit cell cholesterol accumulation by focusing on the main proteins involved in cholesterol homeostasis in response to CD and apoA-I treatment. Materials and Methods: In this experimental study, astrocytes were treated with apoA-I or CD and then lysed in RIPA buffer. We used Western blot to detect protein levels of 3-hydroxy-3-methyl-glutaryl coenzyme A reductase (HMGCR) and ATP-binding cassette transporter A1 (ABCA1). Cell cholesterol content and cholesterol release in the medium were also measured. Results: ApoA-I induced a significant increase in ABCA1 and a mild increase in HMGCR protein level, whereas CD caused a significant increase in HMGCR with a significant decrease in ABCA1. Both apoA-I and CD increased cholesterol release in the medium. A mild, but not significant increase, in cell cholesterol content was seen by apoA-I; however, a significant increase in cell cholesterol was detected when the astrocytes were treated with CD. Conclusion: CD, like apoA-I, depletes cellular cholesterol. This depletion occurs in a different way from apoA-I that is through cholesterol efflux. Depletion of cell cholesterol with CDs led to reduced protein levels of ABCA1 along with increased HMGCR and accumulation of cell cholesterol. This suggested that CDs, unlike apoA-I, could impair the balance between cholesterol synthesis and release, and interfere with cellular function that depends on ABCA1.

BACKGROUND: This study was conducted to determine the effect of fish oil (FO) supplements on high density lipoprotein cholesterol (HDL-C), apolipoprotein-AI (Apo-AI), malondialdehyde (MDA), arylesterase (Aryl), and paraoxonase-1 (PON1) activity in female patients with rheumatoid arthritis (RA).METHODS: A total of 90 RA patients were randomly allocated into two groups that were treated with one FO pearl (1 gr) daily or placebo for three months in addition to conventional treatment. HDL-C, Apo-AI, and MDA levels as well as PON1 and Aryl activities were measured before and after treatment. Independent t-test was used to match basal parameters of case and control groups. Paired t-test was used to assess significance of the differences. Correlation was evaluated by Pearson’s test and the statistical significance was set at P<0.05.RESULTS: No significant differences were noted between FO and placebo patients with regards to age, disease duration, post-menopausal status, conventional therapy, body mass index (BMI), and numbers of swollen and tender joints at the beginning of the study. There were 83 patients who completed the three-month follow up. Serum levels of HDL-C (P=0.018), Apo-AI (P=0.165), Aryl (P=0.026), and PON1 (P=0.049) activity increased, whereas MDA levels decreased significantly with FO supplementation (P=0.077). Significant correlations between increased PON1 activity and both HDL-C (P=0.007, r=0.419) and Apo-AI (P<0.001, r=0.742) concentrations as well as between HDL-C and Apo AI levels (P=0.01, r=0.403) were found.CONCLUSION: According to the results of this study, FO could increase serum HDL-C and PON1 levels and Aryl activity in female patients with RA.