Regular Practice of Physical Activity Improves Cholesterol Transfers to High-Density Lipoprotein (HDL) and Other HDL Metabolic Parameters in Older Adults.

The effects of regular physical activity on two important anti-atherosclerosis functions of high-density lipoprotein (HDL), namely its capacity to receive both forms of cholesterol and its anti-oxidant function, were investigated in this study comparing older adults with young individuals. One-hundred and eight healthy adult individuals were enrolled and separated into the following groups: active older (60-80 yrs, n = 24); inactive older (60-79 yrs, n = 21); active young (20-34 yrs, n = 39); and inactive young (20-35 yrs, n = 24). All performed cardiopulmonary tests. Blood samples were collected in order to assess the following measures: lipid profile, HDL anti-oxidant capacity, paraoxonase-1 activity, HDL subfractions, and lipid transfer to HDL. Comparing active older and active young groups with inactive older and inactive young groups, respectively, the active groups presented higher HDL-C levels (p < 0.01 for both comparisons), unesterified cholesterol transfer (p < 0.01, p < 0.05), and intermediate and larger HDL subfractions (p < 0.001, p < 0.01) than the respective inactive groups. In addition, the active young group showed higher esterified cholesterol transfer than the inactive young group (p < 0.05). As expected, the two active groups had higher VO2peak than the inactive groups; VO2peak was higher in the two younger than in the two older groups (p < 0.05). No differences in unesterified and esterified cholesterol transfers and HDL subfractions were found between active young and active older groups. HDL anti-oxidant capacity and paraoxonase-1 activity were equal in all four study groups. Our data highlight and strengthen the benefits of regular practice of physical activity on an important HDL function, the capacity of HDL to receive cholesterol, despite the age-dependent decrease in VO2peak.

Use of paclitaxel carried in lipid core nanoparticles in patients with late-stage solid cancers with bone metastases: Lack of toxicity and therapeutic benefits.

Patients with heavily pretreated, late-stage cancer and bone metastasis are usually poor candidates for further chemotherapy. Previously, we showed that association to lipid nanoparticles (LDE) drastically decreases the toxicity of anti-cancer drugs. Here, we tested the hypothesis that paclitaxel (PTX) carried in LDE could benefit end-of-life patients with painful bone metastases that had been previously treated with conventional PTX. Methods: Eighteen consecutive patients with late-stage cancer, 8 with breast, 5 with prostate and 5 with lung carcinoma, aged 59±9 years, were included in this study. All were receiving opioid medication. LDE-PTX was administered at 175 mg/m 2 every 3 weeks until disease progression. Clinical imaging examinations and serum biochemistry determinations were performed to monitor disease progression. Intensity of bone pain, use of opioid medications and occurrence of pathological bone fractures were also evaluated. Results: In total, 104 chemotherapy cycles were performed and none of the patients showed clinical and laboratorial toxicities or pathological bone fractures. In all patients, pain was reduced so as to allow substitution of non-opioid for opioid medication. Median progression-free survival (PFS) was four months (95% CI 2.4-5.5), but in five patients PFS was longer than 6 months. Conclusions: Absence of observable clinical and laboratorial toxicities from LDE-PTX treatment, improvement of bone pain and the possible effect on PFS in some patients, despite previous use of conventional PTX, suggest that LDEPTX merits further clinical investigation .

Hydroxychloroquine increased cholesterol transfer to high-density lipoprotein in systemic lupus erythematosus: A possible mechanism for the reversal of atherosclerosis in the disease.

INTRODUCTION: The beneficial effect of hydroxychloroquine (HCQ) in decreasing LDL levels on Systemic Lupus Erythematosus (SLE) is well defined. The influence of this drug on HDL levels is still under debate and information about its effect on cholesterol reverse transport is lacking. OBJECTIVE: To evaluate the effects of HCQ on HDL levels and the transfer of lipids to this lipoprotein in SLE. METHODS: Nineteen SLE patients using only HCQ (SLE WITH HCQ), 19 SLE patients without any therapy (SLE WITHOUT THERAPY), and 19 healthy controls (CONTROL) were included. All three groups were premenopausal women age- and gender-matched. Serum lipids and apolipoproteins were determined by commercial kits. An in vitro transfer of four lipids (14C-Phospolipid, 3H-Cholesteryl ester, 3H-Triglyceride, and 14C-Unesterified cholesterol) from a radioactively labeled nanoemulsion donor to HDL was performed in all participants. RESULTS: Groups had comparable mean age, weight, height, BMI(body mass index), and waist circumference (p > .05). Mean HDL levels were higher in SLE WITH HCQ group compared to SLE WITHOUT THERAPY(58.37 ± 14.04 vs 49.79 ± 8.0 mg/dL; p < .05) but lower than CONTROL (58.37 ± 14.04 vs 68.58 ± 9.99 mg/dL; p < .05). Total cholesterol (TC) and LDL levels were also significantly lower in SLE WITH HCQ compared SLE WITHOUT THERAPY(148.16 ± 16.43 vs 167.11 ± 30.18 mg/dL; p < .05, 75.05 ± 22.52 vs 96.05 ± 25.63 mg/dL; p < .05) and CONTROL (148.16 ± 16.43 vs 174.11 ± 23.70 mg/dL; p < .05, 75.05 ± 22.52 vs 88.53 ± 20.24 mg/dL; p < .05). The in vitro lipid transfer to HDL study revealed a significant difference among the three groups (p = .002) with a higher transfer of unesterified cholesterol(UC) in SLE WITH HCQ compared to SLE WITHOUT THERAPY(5.40 ± 1.05% vs. 4.44 ± 1.05%; p < .05). The latter was significantly decreased compared to CONTROL (5.40 ± 1.05% vs. 5.99 ± 1.71%; p < .05).The percentages of transfer of triacylglycerol (4.93 ± 0.69% vs. 4.50 ± 0.69% vs. 5.14 ± 1.01%; p = .054), esterified cholesterol (5.24 ± 0.70% vs. 4.96 ± 0.89% vs. 5.69 ± 1.27%; p = .079), and phospholipid (15.67 ± 1.03% vs. 15.34 ± 1.44% vs. 16.47 ± 1.89%; p = .066) were similar among groups. CONCLUSION: The present study is the first to demonstrate that HCQ promoted a higher transfer of unesterified cholesterol which may account for the increased HDL levels in lupus patients under HCQ. This desirable effect may underlie the reported reduced atherosclerosis in SLE.

Androgen deprivation therapy improves the in vitro capacity of high-density lipoprotein (HDL) to receive cholesterol and other lipids in patients with prostate carcinoma.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Lipoprotein removal mechanisms and aging: implications for the cardiovascular health of the elderly.

PURPOSE OF REVIEW: The speed of removal from the plasma of apolipoprotein B-containing lipoproteins, for example, chylomicrons, VLDL and LDL is determinant of the plasma concentration of these lipoproteins, is influenced by genetic features and ambient factors, and has implications in atherogenesis. As aging increases the clinical complications of atherosclerosis, it is important to appraise the status of the removal mechanisms in elderly individuals. RECENT FINDINGS: Removal of triglyceride-rich lipoproteins remnants is delayed but the triglyceride breakdown is unchanged in elderly individuals. The discovery of PCSK9, enzyme that degrades LDL receptors, and the recent observation that PCSK9 is elevated in the elderly raises another hypothesis to account for the increased LDL-cholesterol levels in the elderly. The removal of cholesterol from cells by HDL, the first step of cholesterol reverse transport is also less efficient in the elderly, which may compromise the body cholesterol homeostasis. SUMMARY: Aging determines reduction of the efficiency of lipoprotein plasma removal mechanisms, which is implicated in increased incidence of cardia complications. Moreover, aging is frequently accompanied by physical activity reduction, weight gain, and metabolic disturbances that can further decrease the efficacy of the removal mechanisms. This knowledge is important for promoting cardiovascular health in the elderly and prolonging survival.

Lipid transfer to high-density lipoproteins in coronary artery disease patients with and without previous cerebrovascular ischemic events.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Abnormal Thyroid Hormone Status Differentially Affects Bone Mass Accrual and Bone Strength in C3H/HeJ Mice: A Mouse Model of Type I Deiodinase Deficiency.

C3H/HeJ (C3H) mice are deficient of type I deiodinase (D1), an enzyme that activates thyroid hormone (TH), converting thyroxine (T4) to triiodothyronine (T3). Nevertheless, C3H mice present normal serum T3 and a gross euthyroid phenotype. To investigate if a global D1 deficiency interferes in the TH effects on bone, we compared bone growth, bone mass accrual and bone strength of C3H and C57BL/6J (B6) mice under abnormal TH status. Four-week-old female mice of both strains were grouped as Euthyroid, Hypothyroid (pharmacologically-induced), 1xT4 and 10xT4 (hypothyroid animals receiving 1- or 10-fold the physiological dose of T4 /day/16 weeks). Hypothyroidism and TH excess similarly impaired body weight (BW) gain and body growth in both mice strains. In contrast, whereas hypothyroidism only slightly impaired bone mineral density (BMD) accrual in B6 mice, it severely impaired BMD accrual in C3H mice. No differences were observed in serum and bone concentrations of T3 between hypothyroid animals of both strains. Interestingly, treatment with 10xT4 was less deleterious to BMD accrual in C3H than in B6 mice and resulted in less elevated T3 serum levels in B6 than in C3H mice, which is probably explained by the lower D1 activity in C3H mice. In addition, hypothyroidism decreased bone strength only in C3H but not in B6 mice, while TH excess decreased this parameter in both strains. These findings indicate that D1 deficiency contributes to the TH excess-induced differences in bone mass accrual in C3H vs. B6 mice and suggest that deiodinase-unrelated genetic factors might account for the different skeleton responses to hypothyroidism between strains.

Aerobic Training in Young Men Increases the Transfer of Cholesterol to High Density Lipoprotein In Vitro: Impact of High Density Lipoprotein Size.

Exercise training not only improves the plasma lipid profile but also reduces risk of developing coronary heart disease. We investigate whether plasma lipids and high density lipoprotein (HDL) metabolism are affected by aerobic training and whether the high-density lipoprotein cholesterol (HDL-C) levels at baseline influence exercise-induced changes in HDL. Seventy-one male sedentary volunteers were evaluated and allocated in two subgroups, according to the HLD-C levels (< or >40 mg/dL). Participants underwent an 18-week aerobic training period. Blood was sampled before and after training for biochemical analysis. Plasma lipids, apolipoproteins, HDL diameter, and VO2 peak were determined. Lipid transfers to HDL were determined in vitro by incubating plasma samples with a donor lipid artificial nanoemulsion. After the 18-week period of aerobic training, the VO2 peak increased, while the mean body mass index (BMI) decreased. HDL-C concentration was higher after the training period, but low-density lipoprotein cholesterol (LDL-C) and non-HDL-C did not change. The transfer of esterified cholesterol and phospholipids was greater after exercise training, but the triacylglycerol and unesterified cholesterol transfers were unchanged. The HDL particle diameter increased after aerobic training in all participants. When the participants were separated in low-HDL and normal-HDL groups, the postaerobic exercise increment in HDL-C was higher in the low-HDL group, while the transfer of esterified cholesterol was lower. In conclusion, aerobic exercise training increases the lipid transfers to HDL, as measured by an in vitro method, which possibly contributes to the classical elevation of the HDL-C associated with training.

Cholesteryl ester transfer protein (CETP), HDL capacity of receiving cholesterol and status of inflammatory cytokines in patients with severe heart failure.

BACKGROUND: 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. METHODS: 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. RESULTS: 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-1ß, 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). CONCLUSIONS: 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.

Removal of Chylomicron Remnants from the Bloodstream is Delayed in Aged Subjects.

Dietary fats absorbed in the intestine are transported in the circulation as chylomicrons and remnants that have atherogenic potential. Although postprandial lipidemia is increased in older subjects, the specific chylomicron metabolism has not been explored in older subjects nor compared to young subjects, which is the focus of this study. After a 12 h fast, artificially-made emulsions similar to lymph chylomicrons and doubly labeled with radioactive cholesteryl esters and triglycerides were intravenously injected in 23 older (66±4 years) and 20 young (24±3 years) subjects. Sequential blood samples were collected to determine fractional clearance rates (FCR, in min-1) by compartmental analysis. Older subjects had higher LDL-cholesterol (p<0.001) and triglycerides (p<0.0001) than young subjects; HDL-cholesterol presented no difference. The emulsion cholesteryl-ester FCR was lower in older subjects compared to the young (p=0.0001). The emulsion triglyceride FCR did not differ in the two groups. Tested in vitro, however, the lipolysis of the emulsion triglycerides was less intense in the older than in the young subjects. As delayed removal of remnants, indicated by the pronouncedly smaller cholesteryl ester FCR, is related to the presence of cardiovascular diseases, this can be a risk factor which could accelerate atherogenic complications occurring in aged subjects.

Reduction of Atherosclerotic Lesions by the Chemotherapeutic Agent Carmustine Associated to Lipid Nanoparticles.

PURPOSE: After injection in the bloodstream, a lipid nanoparticle (LDE) resembling low-density lipoprotein (LDL) concentrates in atherosclerotic lesions of cholesterol-fed rabbits. Here, rabbits with atherosclerosis were treated with carmustine, an antiproliferative agent used in cancer chemotherapy, associated to LDE to investigate the effects on the lesions. METHODS: Twenty-seven male New Zealand rabbits were fed a 1 % cholesterol diet for 8 weeks. After 4 weeks nine animals were treated with intravenous saline solution, nine with intravenous LDE alone, and nine with intravenous LDE-carmustine (4 mg/kg, weekly for 4 weeks). RESULTS: LDE-carmustine reduced lesion size by 90 % compared to the controls. LDE-carmustine reduced the presence of macrophages, vascular smooth muscle cells, and regulatory T cells in the arterial intima, as well as the presence of matrix metallopeptidase-9, interleukin-1ß and TNF-α and lipoprotein receptors, namely LDL-receptor, LDL-related protein-1, scavenger receptor class B member 1. When injected alone, without association to carmustine, LDE was not different from injected saline solution. CONCLUSIONS: LDE-carmustine treatment resulted in marked reduction of lesion area, of the invasion of the arterial intima by macrophages and vascular smooth muscle cells and pro-inflammatory factors. Therefore, this new formulation shows great potential for therapy of atherosclerotic cardiovascular disease.

Paclitaxel Associated With Lipid Nanoparticles as a New Antiscarring Agent in Experimental Glaucoma Surgery.

PURPOSE: To investigate the effects of paclitaxel associated with lipid nanoemulsions (LDE-PTX) on postoperative scarring in rabbits undergoing trabeculectomy. METHODS: Thirty-four rabbits that underwent trabeculectomy were allocated to four groups: LDE-PTX/SC (n = 9), treated with LDE-PTX (1.5 mg, intraoperative subconjunctival injection); LDE-PTX/IV (n = 9), treated with LDE-PTX (4 mg/kg per day intravenously) at the end of the surgery and once per week for 3 weeks; MMC (n = 9), treated with intraoperative 0.4 mg/mL mitomycin-C for 3 minutes; and control group (CTL, n = 7), without treatment. Bleb characteristics and IOP were evaluated over 4 weeks. Animals were killed on day 28. Histologic analyses were performed to assess the amount of scarring and toxicity to the conjunctiva and ciliary body. RESULTS: Groups were similar with respect to IOP and anterior chamber depth during the 28-day observation period. The LDE-PTX/SC, LDE-PTX/IV, and MMC groups showed greater bleb height than CTL on days 14 and 21 (P < 0.001). The LDE-PTX/SC, LDE-PTX/IV, and MMC groups showed longer bleb survival time than CTL (P < 0.001). The LDE-PTX/SC, LDE-PTX/IV, and MMC groups were equally effective in reducing fibrosis (P < 0.001), number of blood vessels (P < 0.001), and chronic inflammatory cells (P < 0.01) at the surgical site. However, LDE-PTX/SC and LDE-PTX/IV treatments had lower conjunctival (P < 0.001) and ciliary body toxicity (P < 0.01), compared with MMC. CONCLUSIONS: The LDE-PTX/SC was effective in reducing the scarring process following trabeculectomy to the same extent as MMC, but with considerably less toxicity to the conjunctiva and ciliary body. The LDE-PTX/IV was somewhat less effective than LDE-PTX/SC or MMC, but could have potential as a postoperative adjuvant treatment. Therefore, the LDE-PTX preparation in both administration routes may offer promising options for wound-healing modulation in the surgical treatment of glaucoma.

HDL metabolism and atheroprotection: predictive value of lipid transfers.

High-density lipoprotein (HDL) intravascular metabolism is complex, and the major HDL functions are esterification of cholesterol and reverse cholesterol transport, in which cholesterol from cells is excreted in bile. HDL has also several other antiatherogenic functions: antioxidative, vasodilatatory, anti-inflammatory, antiapoptotic, anti thrombotic, and anti infectious. Low HDL cholesterol is a major risk factor for cardiovas cular disease (CVD) and high HDL cholesterol may favor the many protective abilities of HDL. However, aspects of HDL function can be independent of HDL cholesterol levels, including the efflux of cholesterol from cells to HDL. Some populations show low incidence of CVD despite their low HDL cholesterol. Lipid exchange between HDL and other lipoproteins and cells is fundamental in HDL metabolism and reverse cholesterol transport. By determining HDL composition, lipid transfers can also affect HDL functions that depend on proteins that anchor on HDL particle surface. Cholesteryl ester protein (CETP) and phospholipid transfer protein facilitate lipid transfers among lipoprotein classes, but the role of the lipid transfers and transfer proteins in atherosclerosis and other diseases is not well established. CETP has become a therapeutic target because CETP inhibitors increase HDL cholesterol, but to date the clinical trials failed to show benefits for the patients. Recently, we introduced a practical in vitro assay to evaluate the simultaneous transfer from a donor nanoemulsion to HDL of unesterified and esterified cho lesterol, phospholipids, and triglycerides. Groups of subjects at different clinical, nutritional, and training conditions were tested, and among other findings, lower transfer ratios of unesterified cholesterol to HDL were predictors of the presence of CVD.

Lipoprotein metabolism in patients with type 1 diabetes under intensive insulin treatment.

BACKGROUND: Type 1 diabetes (T1DM) is frequently accompanied by dyslipidemia related with insulin-dependent steps of the intravascular lipoprotein metabolism. T1DM dyslipidemia may predispose to precocious cardiovascular disease and the lipid status in T1DM under intensive insulin treatment has not been sufficiently explored. The aim was to investigate the plasma lipids and the metabolism of LDL and HDL in insulin-treated T1DM patients with high glycemic levels. METHODS: Sixteen male patients with T1DM (26 ± 7 yrs) with glycated hemoglobin >7%, and 15 control subjects (28 ± 6 yrs) were injected with a lipid nanoemulsion (LDE) resembling LDL and labeled with (14)C-cholesteryl ester and (3)H-free-cholesterol for determination of fractional clearance rates (FCR, in h-1) and cholesterol esterification kinetics. Transfer of labeled lipids from LDE to HDL was assayed in vitro. RESULTS: LDL-cholesterol (83 ± 15 vs 100 ± 29 mg/dl, p=0.08) tended to be lower in T1DM than in controls; HDL-cholesterol and triglycerides were equal. LDE marker 14C-cholesteryl ester was removed faster from plasma in T1DM patients than in controls (FCR=0.059 ± 0.022 vs 0.039 ± 0.022h-1, p=0.019), which may account for their lower LDL-cholesterol levels. Cholesterol esterification kinetics and transfer of non-esterified and esterified cholesterol, phospholipids and triglycerides from LDE to HDL were also equal. CONCLUSION: T1DM patients under intensive insulin treatment but with poor glycemic control had lower LDL-cholesterol with higher LDE plasma clearance, indicating that LDL plasma removal was even more efficient than in controls. Furthermore, HDL-cholesterol and triglycerides, cholesterol esterification and transfer of lipids to HDL, an important step in reverse cholesterol transport, were all normal. Coexistence of high glycemia levels with normal intravascular lipid metabolism may be related to differences in exogenous insulin bioavailabity and different insulin mechanisms of action on glucose and lipids. Those findings may have important implications for prevention of macrovascular disease by intensive insulin treatment.

Breakdown of the blood-ocular barrier as a strategy for the systemic use of nanosystems.

Several drug delivery systems have been proposed to overcome physiological barriers, improving ocular bioavailability. Systemic routes are seldom used due to the blood-ocular barrier. Novel drug delivery systems based on nanotechnology techniques have been developed to overcome ocular physiological barriers. This non-systematic review suggests the utilization of a transitory blood-ocular breakdown to allow the access of drugs by nanotechnology drug delivery systems via the systemic route. We discuss the possible ways to cause the breakdown of the blood-ocular barrier: acute inflammation caused by intraocular surgery, induced ocular hypotony, and the use of inflammatory mediators. The suitability of use of the systemic route and its toxic effects are also discussed in this article.

Lipid transfers to HDL are predictors of precocious clinical coronary heart disease.

BACKGROUND: High-density-lipoprotein (HDL) has several antiatherogenic properties and, although the concentration of HDL-cholesterol negatively correlates with incidence of coronary artery disease (CAD), this is not sufficient to evaluate the overall HDL protective role. The aim was to investigate whether precocious CAD patients show abnormalities in lipid transfers to HDL, a fundamental step in HDL metabolism and function. METHODS: Thirty normocholesterolemic CAD patients aged <50 y and 30 controls paired for sex, age and B.M.I. were studied. Fasting blood samples were collected for the in vitro lipid transfer assay and plasma lipid determination. A donor nanoemulsion labeled with radioactive free-cholesterol, cholesteryl esters, phospholipids and triglycerides was incubated with whole plasma and after chemical precipitation of non-HDL fractions, supernatant was counted for radioactivity in HDL. RESULTS: LDL and HDL-cholesterol and triglycerides were equal in both groups. Transfers of free-cholesterol (3.8±1.2%vs 7.0±3.3%,p<0.0001) and triglycerides (3.7±1.7%vs 4.9±1.9%, p=0.0125) were diminished in CAD patients whereas cholesteryl ester transfer increased (6.5±1.9%vs 4.8±1.8%, p=0.0008); phospholipid transfer was equal (17.8±3.5% vs 19.5±3.9%). CONCLUSION: Alterations in the transfer of lipids to HDL may constitute a new marker for precocious CAD and relation of this metabolic alteration with HDL antiatherogenic function should be investigated in future studies.

Reduction of atherosclerotic lesions in rabbits treated with etoposide associated with cholesterol-rich nanoemulsions.

OBJECTIVES: Cholesterol-rich nanoemulsions (LDE) bind to low-density lipoprotein (LDL) receptors and after injection into the bloodstream concentrate in aortas of atherosclerotic rabbits. Association of paclitaxel with LDE markedly reduces the lesions. In previous studies, treatment of refractory cancer patients with etoposide associated with LDE had been shown devoid of toxicity. In this study, the ability of etoposide to reduce lesions and inflammatory factors in atherosclerotic rabbits was investigated. METHODS: Eighteen New Zealand rabbits were fed a 1% cholesterol diet for 60 days. Starting from day 30, nine animals were treated with four weekly intravenous injections of etoposide oleate (6 mg/kg) associated with LDE, and nine control animals were treated with saline solution injections. RESULTS: LDE-etoposide reduced the lesion areas of cholesterol-fed animals by 85% and intima width by 50% and impaired macrophage and smooth muscle cell invasion of the intima. Treatment also markedly reduced the protein expression of lipoprotein receptors (LDL receptor, LDL-related protein-1, cluster of differentiation 36, and scavenger receptor class B member 1), inflammatory cytokines (interleukin-1ß and tumor necrosis factor-α), matrix metallopeptidase-9, and cell proliferation markers (topoisomerase IIα and tubulin). CONCLUSION: The ability of LDE-etoposide to strongly reduce the lesion area and the inflammatory process warrants the great therapeutic potential of this novel preparation to target the inflammatory-proliferative basic mechanisms of the disease.

An artificial nanoemulsion carrying paclitaxel decreases the transplant heart vascular disease: a study in a rabbit graft model.

OBJECTIVE: In previous studies cholesterol-rich nanoemulsions (LDE) resembling low-density lipoprotein were shown to concentrate in atherosclerotic lesions of rabbits. Lesions were pronouncedly reduced by treatment with paclitaxel associated with LDE. This study aimed to test the hypothesis of whether LDE-paclitaxel is able to concentrate in grafted hearts of rabbits and to ameliorate coronary allograft vasculopathy after the transplantation procedure. METHODS: Twenty-one New Zealand rabbits fed 0.5% cholesterol were submitted to heterotopic heart transplantation at the cervical position. All rabbits undergoing transplantation were treated with cyclosporin A (10 mg · kg(-1) · d(-1) by mouth). Eleven rabbits were treated with LDE-paclitaxel (4 mg/kg body weight paclitaxel per week administered intravenously for 6 weeks), and 10 control rabbits were treated with 3 mL/wk intravenous saline. Four control animals were injected with LDE labeled with [(14)C]-cholesteryl oleate ether to determine tissue uptake. RESULTS: Radioactive LDE uptake by grafts was 4-fold that of native hearts. In both groups the coronary arteries of native hearts showed no stenosis, but treatment with LDE-paclitaxel reduced the degree of stenosis in grafted hearts by 50%. The arterial luminal area in grafts of the treated group was 3-fold larger than in control animals. LDE-paclitaxel treatment resulted in a 7-fold reduction of macrophage infiltration. In grafted hearts LDE-paclitaxel treatment reduced the width of the intimal layer and inhibited the destruction of the medial layer. No toxicity was observed in rabbits receiving LDE-paclitaxel treatment. CONCLUSIONS: LDE-paclitaxel improved posttransplantation injury to the grafted heart. The novel therapeutic approach for heart transplantation management validated here is thus a promising strategy to be explored in future clinical studies.

Double disruption of α2A- and α2C-adrenoceptors results in sympathetic hyperactivity and high-bone-mass phenotype.

Evidence demonstrates that sympathetic nervous system (SNS) activation causes osteopenia via ß(2)-adrenoceptor (ß2-AR) signaling. Here we show that female mice with chronic sympathetic hyperactivity owing to double knockout of adrenoceptors that negatively regulate norepinephrine release, α(2A)-AR and α(2C)-AR (α(2A) /α(2C)-ARKO), present an unexpected and generalized phenotype of high bone mass with decreased bone resorption and increased formation. In α(2A) /α(2C)-ARKO versus wild-type (WT) mice, micro-computed tomographic (µCT) analysis showed increased, better connected, and more plate-shaped trabeculae in the femur and vertebra and increased cortical thickness in the vertebra, whereas biomechanical analysis showed increased tibial and femoral strength. Tibial mRNA expression of tartrate-resistant acid phosphatase (TRACP) and receptor activator of NF-κB (RANK), which are osteoclast-related factors, was lower in knockout (KO) mice. Plasma leptin and brain mRNA levels of cocaine amphetamine-regulated transcript (CART), which are factors that centrally affect bone turnover, and serum levels of estradiol were similar between mice strains. Tibial ß(2)-AR mRNA expression also was similar in KO and WT littermates, whereas α(2A)-, α(2B)- and α(2C)-AR mRNAs were detected in the tibia of WT mice and in osteoblast-like MC3T3-E1 cells. By immunohistochemistry, we detected α(2A)-, α(2B)-, α(2C)- and ß(2)-ARs in osteoblasts, osteoclasts, and chondrocytes of 18.5-day-old mouse fetuses and 35-day-old mice. Finally, we showed that isolated osteoclasts in culture are responsive to the selective α(2)-AR agonist clonidine and to the nonspecific α-AR antagonist phentolamine. These findings suggest that ß(2)-AR is not the single adrenoceptor involved in bone turnover regulation and show that α(2)-AR signaling also may mediate the SNS actions in the skeleton.