👤 Raul Cavalcante Maranhão

Lipid Nanoparticles (LDE) have been used as a drug delivery vehicle to treat various diseases. LDEs resemble the structure of human low-density lipoprotein (LDL), but lack apoliprotein B (apo-B). The aim of this study was to determine whether changes in the proportion of unesterified cholesterol (UC) or triacylglycerols (TG) affect the physical stability of LDE in aqueous solutions over a six-month observation period, as analysed by Ultra Small-angle X-ray Scattering (USAXS), Dynamic Light Scattering (DLS) and zeta potential measurements. It was shown that variations in UC or TG content in the initial lipid mixture did not alter the size of the resulting LDE nanoparticles, which remained within the 30-35 nm range. This particle size was maintained for up to three months in formulations with varying TG content and up to four months in those with varying UC content. Thereafter, a progressive increase in nanoparticle size was observed, which suggests enhanced aggregate formation and reduced of LDE stability between 3 and 6 months of storage. This loss of stability did not appear to be directly related to changes in UC or TG composition. Notably, USAXS and DLS measurements yielded comparable results, which reinforces the reliability of the data. In addition, the zeta potential remained close to zero for all seven nanoparticle compositions throughout the six months, indicating that all LDE formulations had electrostatic neutral potential and remain so when they progressively aggregate with time. Complementary analyses also showed that LDE particles are, on average, spherical in shape. Overall, these findings provide relevant insights for the rational design of lipid mixtures in the preparation of nanoemulsions for drug delivery applications. Show less

Familial hypercholesterolemia (FH) is characterized by elevated low-density lipoprotein cholesterol (LDL-C) and increased risk of premature coronary atherosclerosis. Functional aspects of high-density lipoprotein (HDL), including cholesterol transfer capacity, may contribute to cardiovascular risk heterogeneity in FH. To investigate whether cholesterol transfer to HDL and other HDL-related parameters are associated with coronary artery disease (CAD) in patients with heterozygous FH (HeFH). Fifty-three genetically confirmed FH patients (mean age: 49.2 years; 73.6% female) were included. Twenty-seven had plaques, while 26 had no vessel abnormalities as determined by coronary computed tomography angiography. The transfer of both unesterified and esterified cholesterol (UC and EC) to HDL, as well as HDL antioxidant capacity, particle size, and subfractions, plasma concentrations of cholesteryl ester transfer protein (CETP) and lecithin-cholesterol acyltransferase (LCAT), and paraoxonase-1 (PON-1) activity were assessed. Family history of premature CAD (P < .028) and tendinous xanthomas (P = .014) were more frequent in those with plaques. No differences were found in apolipoprotein (apo) B, LDL-C, LDL-C year score, lipoprotein(a), non-HDL-C, apo A-I, HDL-C, HDL subfractions, or triglycerides. Transfer of lipids to HDL and antioxidant capacity did not differ between the groups. LCAT concentrations and PON-1 activity were also similar. In contrast, CETP concentration was higher in those with plaques (P < .008). However, only family history of early CAD (odds ratio [OR]: 4.12, 95% CI, 1.23-13.80, P = .022) and xanthomas (OR: 3.65, 95% CI, 1.06-12.60, P = .040) were independently associated with plaques. Among patients with HeFH, no HDL-related parameter was independently associated with subclinical CAD. Show less

Low high-density lipoprotein (HDL)-cholesterol is frequent in patients with peripheral artery disease (PAD) and also in type 2 diabetes mellitus (T2DM), the major risk factor for PAD. The transfer of cholesterol from the other lipoproteins to HDL is an important aspect of HDL metabolism and function, and may contribute to atherogenic mechanisms that lead to PAD development. The aim of this study was to investigate the status of cholesterol transfers in patients with PAD without or with T2DM. Patients with PAD ( Low-density lipoprotein (LDL)-cholesterol and triglycerides were similar in the three groups. Compared to controls, HDL-C was lower in PAD + DM ( Deficient cholesterol transfer to HDL may play a role in PAD pathogenesis. Since UC transfer to HDL was lower in PAD + DM compared to PAD alone, it is possible that defective HDL metabolism may contribute to the higher PAD incidence in patients with T2DM.Keywords. Show less

Androgen deprivation therapy (ADT) is widely used in the treatment of testosterone-dependent prostate carcinomas. ADT often increases plasma LDL and HDL cholesterol and triglycerides. The aim was to test whether ADT changes the transfer of lipids to HDL, an important aspect of this metabolism and HDL protective functions, and related parameters. Sixteen volunteers with advanced prostate carcinoma submitted to pharmacological ADT or orchiectomy had plasma collected shortly before and after 6 months of ADT. In vitro transfer of lipids to HDL was performed by incubating plasma with donor emulsion containing radioactive lipids by 1 h at 37 °C. After chemical precipitation of apolipoprotein B-containing lipoprotein, the radioactivity of HDL fraction was counted. ADT reduced testosterone to nearly undetectable levels and markedly diminished PSA. ADT increased the body weight but glycemia, triglycerides, LDL and HDL cholesterol, HDL lipid composition and CETP concentration were unchanged. However, ADT increased the plasma unesterified cholesterol concentration (48 ± 12 vs 56 ± 12 mg/dL, p = 0.019) and LCAT concentration (7.15 ± 1.81 vs 8.01 ± 1.55μg/mL, p = 0.020). Transfer of unesterified (7.32 ± 1.09 vs 8.18 ± 1.52%, p < 0.05) and esterified cholesterol (6.15 ± 0.69 vs 6.94 ± 1.29%, p < 0.01) and of triglycerides (6.37 ± 0.43 vs 7.18 ± 0.91%, p < 0.001) to HDL were increased after ADT. Phospholipid transfer was unchanged. Increase in transfer of unesterified and esterified cholesterol protects against cardiovascular disease, as shown previously, and increased LCAT favors cholesterol esterification and facilitates the reverse cholesterol transport. Thus, our results suggest that ADT may offer anti-atherosclerosis protection by improving HDL functional properties. This could counteract, at least partially, the eventual worse effects on plasma lipids. Show less

Patients with coronary artery disease (CAD) and previous ischemic cerebrovascular events (ICVE, ischemic stroke, or transitory ischemic attack) constitute a high-risk subgroup for cardiovascular outcomes. High-density lipoprotein cholesterol (HDL-C) levels are correlated with cardiovascular events. Lipid transfer to HDL affects structure size and HDL subclass profile. Impairment of this transfer could influence ischemic risk seen in patients with CAD + ICVE. The objective was to evaluate the HDL ability to receive the lipids in patients with CAD with or without ICVE. Patients with CAD + ICVE (n = 60) and patients with CAD only (n = 60) were matched by age, sex, acute coronary syndromes (ACS) event type, and time elapsed between the ACS event and inclusion in the study. Lipid transfer to HDL was evaluated by incubating donor lipid nanoparticles labeled with radioactive unesterified cholesterol (UC) and esterified cholesterol (EC), phospholipid (PL), and triglyceride (TG) with whole plasma. After the chemical precipitation of non-HDL fractions and nanoparticles, the supernatant was counted for HDL radioactivity. CAD + ICVE group presented with impaired lipid transfer to HDL for PL (CAD + ICVE: 21.14 ± 2.7% vs CAD: 21.67 ± 3.1%, P = .03), TG (CAD + ICVE: 4.88 ± 0.97% vs CAD: 5.63 ± 0.92%, P = .002), and UC (CAD + ICVE: 5.55 ± 1.19% vs CAD: 6.16 ± 1.14%, P = .009). Lipid transfer to HDL was similar in both groups for EC. Adjusted models showed similar results. Patients with CAD and ICVE have reduced lipid transfer to HDL compared to those with CAD only. Dysfunctional HDL may account for the higher incidence of ischemic outcomes observed in this population. Show less

Elevation of low-density lipoprotein (LDL) cholesterol is the hallmark of the dyslipidemia observed in hypothyroidism, but alterations on high-density lipoprotein (HDL) plasma levels and metabolism are less understood. The aim of this study was to explore aspects of HDL metabolism and enzymes that act on HDL after a short period of overt hypothyroidism. Eighteen women (age 44 ± 11 years; body mass index 27.9 ± 5.2 kg/m Thyrotropin and free thyroxine confirmed hypothyroidism; low thyroglobulin and radioiodine uptake indicated near absence of thyroid tissue. LDL cholesterol (125 ± 35 vs. 167 ± 40 mg/dL; p = 0.0002), HDL cholesterol (HDL-C; 39 ± 8 vs. 46 ± 10 mg/dL; p = 0.0025), non-HDL-C (149 ± 38 vs. 201 ± 46 mg/dL; p < 0.0001), unesterified cholesterol (53 ± 10 vs. 70 ± 16 mg/dL; p = 0.0003), apolipoprotein (apo) A-I (1.32 ± 0.19 vs. 1.44 ± 0.22 g/L; p < 0.04), and apo B (0.97 ± 0.25 vs. 1.31 ± 0.28 g/L; p < 0.0001) plasma concentrations were all higher in hypothyroidism compared to values in the euthyroid state, but triglycerides and Lp(a) were unchanged. There were no changes in HDL particle size and lipid composition, cholesteryl ester transfer protein and lecithin cholesterol acyltransferase concentrations and in paraoxonase-1 activity. Regarding the in vitro assay to estimate lipid transfer to HDL, there were no changes when comparing the euthyroid to the hypothyroid state, but when adjusted for HDL-C, the unesterified cholesterol (0.14 ± 0.03 vs. 0.11 ± 0.02; p < 0.0001), triglycerides (0.11 ± 0.02 vs. 0.09 ± 0.02; p < 0.0001), phospholipids (0.44 ± 0.09 vs. 0.40 ± 0.07; p = 0.0205), and esterified cholesterol (0.14 ± 0.03 vs. 0.13 ± 0.03; p = 0.0043) transfer to HDL were all diminished in hypothyroidism. In short-term hypothyroidism, HDL-C increased, but this did not increase the capacity of the HDL fraction to receive lipids or the activity of paraoxonase-1, the anti-oxidation enzyme associated to HDL. Show less

Heart failure (HF) courses with chronic inflammatory process and alterations in lipid metabolism may aggravate the disease. The aim was to test whether the severity of HF, using brain natriuretic peptide (BNP) as a marker, is associated with alterations in functional aspects of HDL, such as lipid transfer, cholesterol ester transfer protein (CETP) and lecithin-cholesterol acyltransferase (LCAT) concentration. Twenty-five HF patients in NYHA class I/II and 23 in class III/IV were enrolled. Plasma lipids, apolipoproteins, CETP, LCAT, oxidized-LDL (oxLDL) and paraoxonase-1 (PON-1) activity were determined. Lipid transfer from a donor artificial nanoparticle to HDL was measured by in vitro assay. Total cholesterol (p = 0.049), LDL-C (p = 0.023), non-HDL-C (p = 0.029) and CETP, that promotes lipid transfer among lipoproteins (p = 0.013), were lower in III/IV than in I/II group. Triglycerides, HDL-C, apo A-I, apo B, oxLDL, LCAT, enzyme that catalyzes serum cholesterol esterification, PON-1 activity, and in vitro transfers of cholesterol, triglycerides and phospholipids to HDL, important steps in HDL metabolism, were equal. IL-8 was higher in III/IV (p = 0.025), but TNFα, IL-1β, IL-6 and MCP-1 were equal. BNP was negatively correlated with CETP (r = - 0.294; p = 0.042) and positively correlated with IL-8 (r = 0.299; p = 0.039). Our results disclosed the relationship between CETP levels and HF severity, by comparing two HF groups and by correlation analysis. Lower CETP levels may be a marker of HF aggravation and possibly of worse prognosis. Practical applications of this initial finding, as the issue whether CETP could be protective against HF aggravation, should be explored in larger experimental and clinical studies. Show less

The transport of lipids from the artery wall is one of the most essential anti-atherogenic functions of high-density lipoprotein (HDL). Recent reports of changes in the HDL composition, during myocardial infarction (MI), suggest that this function may be altered. Forty-one consecutive patients with ST-segment elevation MI enrolled at the Brasilia Heart Study were selected. The following HDL-related measures were determined upon admission (D1) and on the fifth day (D5) after MI: C-reactive protein, CETP and PLTP activity, HDL composition, efflux of cholesterol from J774 macrophages to HDL, and transfer of unesterified and esterified cholesterol, triglycerides and phospholipids from a donor nanoemulsion to HDL. From D1 to D5, the activity of CETP decreased by 25%, but PLTP activity remained unchanged. Esterified cholesterol (-23%) and phospholipid (-9.5%) contents of HDL decreased. Transfer of triglycerides (-36.5%) and esterified cholesterol (-14.7%) to HDL from nanoemulsions was reduced, but other lipids transfers were unchanged. Cholesterol efflux to HDL was also diminished by 8.5% (p=0.04) on D5 compared to D1. It was more pronounced in patients above the 75th percentile of C-reactive protein. After an MI, a simultaneous decrease in lipid transfer to HDL and in the capacity of HDL to efflux cholesterol from cells occurs. Thus, HDL with inferior atheroprotective properties may be generated in the acute post-MI period. Show less

Plasma lipids have been extensively studied in sedentary and in subjects practicing exercise training, but not in extreme inactivity as occurs in bedridden patients. This is important for the care of bedridden patients and understanding the overall plasma lipid regulation. Here, we investigated plasma lipids, lipid transfers to HDL and inflammatory markers in bedridden patients. Fasting blood samples were collected from 23 clinically stable bedridden patients under long-term care (>90 days) and 26 normolipidemic sedentary subjects, paired for age and gender. In vitro transfer of four lipids to HDL was performed by incubating plasma with donor nanoparticles containing radioactive lipids. Total (193 ± 36 vs 160 ± 43, p = 0.005), LDL (124 ± 3 vs 96 ± 33 p = 0.003) and HDL-cholesterol (45 ± 10 vs 36 ± 13, p = 0.008), apolipoprotein A-I (134 ± 20 vs 111 ± 24, p = 0.001) and oxidized LDL (53 ± 13 vs 43 ± 12, p = 0.011) were lower in bedridden patients, whereas triglycerides, apolipoprotein B, CETP and LCAT were equal in both groups. Transfers of all lipids, namely unesterified cholesterol, cholesterol esters, triglycerides and phospholipids, to HDL were lower in bedridden patients, probably due to their lower HDL-cholesterol levels. Concentrations of IL-1β, IL-6, IL-8, HGF and NGF were higher in bedridden patients compared to sedentary subjects. In conclusion, inactivity had great impact on HDL, by lowering HDL-cholesterol, apolipoprotein A-I and thereby cholesterol transfers to the lipoprotein, which suggests that inactivity may deteriorate HDL protection beyond the ordinary sedentary condition. Show less