Association between plasminogen activator inhibitor-1 and severity of liver injury and cardiovascular risk in children with non-alcoholic fatty liver disease.

BACKGROUND: Plasminogen activator inhibitor-1 (PAI-1) is the primary inhibitor of the endogenous fibrinolytic system and is known to be increased in obesity, insulin resistance and non-alcoholic fatty liver disease (NAFLD). We previously demonstrated that PAI-1 levels were closely related to the amount of hepatic steatosis in children. OBJECTIVES: The aim of this study was to characterize plasma PAI-1 in relationship to severity of inflammation and fibrosis, as well as to plasma lipids in children with NAFLD. METHODS: In 44 children with NAFLD, plasma PAI-1 levels and lipids were measured at the time of a liver biopsy. Hepatic histological features were systematically scored. Trend analysis was applied to determine the correlation of plasma PAI-1 levels with lipid markers for cardiovascular disease and with the staging of histological features in the liver. RESULTS: We found that plasma PAI-1 levels were significantly increased in children with increased severity of steatosis, lobular inflammation, ballooning and fibrosis. Furthermore, PAI-1 was strongly correlated with plasma lipids and insulin resistance indices. CONCLUSIONS: PAI-1 appears to be tightly related to both histologic severity of NAFLD as well as systemic features of the disease including insulin resistance and dyslipidemia. PAI-1 may be a mediator of disease progression and future cardiovascular complications in children with NAFLD.

Circulating progenitor cells in patients with familial hypercholesterolemia.

OBJECTIVE: Familial hypercholesterolemia (FH) is a genetic disease with very high levels of circulating low density lipoprotein cholesterol (LDL-C) levels that leads to accelerated atherosclerosis. Lipoprotein apheresis is an effective treatment option for patients with FH and results in reduced cardiovascular morbidity and mortality. Circulating progenitor cells (CPCs) are markers of overall vascular health and diminished levels have been associated with decreased reparative potential and worse outcomes. We assessed the short-term change in CPC levels following a single lipoprotein apheresis session in FH patients who are already on stable lipoprotein apheresis therapy. We hypothesized that in addition to a reduction in atherogenic lipids, the cardiovascular benefit from lipoprotein apheresis therapy is mediated by enhanced vascular reparative capacity through mobilization of CPCs. METHODS: Eight FH patients (1 homozygous and 7 heterozygous) on stable lipoprotein apheresis therapy for at least three months had CPCs measured at baseline (prior to apheresis) and two hours after apheresis. Results were compared with data from age-matched hyperlipidemic (HLP) patients on statin therapy and healthy volunteers. RESULTS: FH patients had higher baseline circulating levels of CD34+/CD133+ and CD34+/CD133+/CXCR4+ cells compared to HLP and healthy subjects. There was no significant change in CPCs after apheresis in FH patients. CONCLUSIONS: FH patients had higher CPC counts at baseline compared to age-matched HLP and healthy controls, suggesting activation of reparative mechanism in this high risk population. Larger studies are needed to better characterize differences in CPC counts between FH subjects and HLP patients over time.

Cardiometabolic risks vary by weight status in pediatric kidney and liver transplant recipients: A cross-sectional, single-center study in the USA.

There is an increasing need to understand long-term metabolic changes and resultant comorbidities because life expectancy is increasing after pediatric kidney and liver transplants. We evaluated differences in classic and novel cardiometabolic biomarkers among obese and normal weight adolescent transplant recipients. We enrolled a total of 80 adolescent (mean±SD, 14.8 years ±3.0) transplant recipients (63 kidney, 17 liver) with mean duration from transplantation of 6.0 (±4.1) years. Among kidney transplant recipients, overweight and obese individuals had higher leptin (16.7 vs 7.5 µg/mL, P<.001), lower HDL (1.1 vs 1.3 mmol/L, P=.02), higher free fatty acid (0.6 vs 0.5 mmol/L, P=.03), higher apoB-to-apoA1 ratio (0.8 vs 0.6, P=.03), and higher glucose (5.8 vs 4.3 mmol/L, P=.03) concentrations compared to normal weight individuals. Regardless of obesity status, over half of all participants (57.5%) were considered at high cardiometabolic risk using consensus guidelines, and this was more pronounced for kidney transplant recipients (61.9%). Post-transplantation adolescents have increased cardiometabolic risk characterized by traditional risk factors of obesity and diabetes. The presence of obesity significantly worsens biomarkers of cardiometabolic risk. Future studies should explore whether treatment of obesity can improve the health and long-term outcomes for children undergoing solid organ transplant.

Meal-induced increases in C-reactive protein, interleukin-6 and tumour necrosis factor α are attenuated by prandial + basal insulin in patients with Type 2 diabetes.

AIM: To determine if a regimen with prandial + basal insulin compared with basal insulin attenuates post-meal inflammatory and glycative biomarkers in patients with Type 2 diabetes. METHODS: This test-meal sub-study in the USA is from a previously reported clinical trial comparing the effect on glycaemic control of 24 weeks of thrice-daily pre-meal insulin lispro mix 50 (50% insulin lispro, 50% insulin lispro protamine suspension) or bedtime insulin glargine, both plus metformin. In the sub-study, glucose, insulin, triglycerides, high-sensitivity C-reactive protein, tumour necrosis factor α, interleukin-6, methylglyoxal and 3-deoxyglucosone were measured during the post-meal period of a mixed-meal breakfast at the final visit. Prandial + basal (n = 25) and basal (n = 21) insulin were administered at the same times as during the previous 24 weeks. RESULTS: Post-meal, the prandial + basal insulin group had significantly higher insulin, lower glucose and triglycerides, as well as lower high-sensitivity C-reactive protein, tumour necrosis factor α and interleukin-6, than the basal insulin group. Glucose incremental area under the concentration curve significantly correlated with high-sensitivity C-reactive protein, tumour necrosis factor α, interleukin-6, methylglyoxal and 3-deoxyglucosone incremental area under the concentration curve. Insulin incremental area under the concentration curve correlated inversely with high-sensitivity C-reactive protein and tumour necrosis factor α incremental area under the concentration curve. However, after adjusting for glucose incremental area under the concentration curve, these inverse correlations were no longer significant. Triglyceride incremental area under the concentration curve was not correlated with any biomarker incremental area under the concentration curve. CONCLUSIONS: Controlling post-meal hyperglycaemia with prandial + basal insulin in patients with Type 2 diabetes attenuates meal-induced increases in high-sensitivity C-reactive protein, interleukin-6 and tumour necrosis factor α compared with basal insulin. The rise in post-meal glucose, but not triglycerides, significantly correlated with the rise in post-meal inflammatory and glycative biomarkers.

Dyslipidemia in obese cats.

Obesity is an important endocrine disorder in cats and is a risk factor for diabetes similar to humans. The goal of this study was to examine the effect of long-term obesity and different diets (high protein, and high carbohydrate supplemented with saturated fatty acids or n-3 polyunsaturated fatty acids) on plasma lipids in the fasted and fed states in 12 lean (LEAN) and 12 obese (OBESE) cats with ultracentrifugation, and nuclear magnetic resonance spectroscopy. OBESE had higher plasma non-esterified fatty acids and triglycerides, as well as very-low-density-lipoproteins (VLDL) consisting primarily of medium-sized particles. The concentration of low-density-lipoproteins (LDL) was comparable between the groups, although OBESE had mostly very small, whereas LEAN had mostly large particles. The concentration of high-density-lipoproteins (HDL) was lower in OBESE and consisted primarily of small particles. Plasma triglycerides, and triglycerides and cholesterol in all lipoproteins increased postprandially. Different diets had little effect on lipids. Our results show that long-term obese cats develop similar lipoprotein changes to humans, yet, hypertension and atherosclerosis have not been described in obese cats. This suggests that dyslipidemia alone is not sufficient to induce hypertension and atherosclerosis. Other anti-atherogenic factors may be present in the obese, dyslipidemic cat.

Antiretroviral therapy in HIV-positive men is associated with increased apolipoprotein CIII in triglyceride-rich lipoproteins.

OBJECTIVES: Dyslipidaemia has become a common problem in HIV disease, especially in patients on current antiretroviral therapy. However, the pathogenic mechanisms involved are not well understood or documented using conventional lipid measurements. METHODS: Using a cross-sectional design, the prevalence of abnormal standard lipid measurements and novel biomarkers for abnormal lipid metabolism was determined in 271 HIV-positive men from two HIV clinics in Atlanta, GA, USA. RESULTS: A total of 147 men were treated with protease inhibitors (PIs) for >3 months (54%), 84 were treated with nonnucleoside reverse transcriptase inhibitors (NNRTIs) for >3 months (31%) and 40 had not received antiretroviral therapy in the past 3 months (15%). Patients being treated with a PI had higher total cholesterol and triglyceride (TG) levels than patients on no therapy (P<0.05 for each). Patients in the NNRTI group had higher TG, lower high-density lipoprotein (HDL) levels, and higher low-density lipoprotein (LDL) levels than patients on no therapy (P<0.05 for each). Patients treated with either PIs or NNRTIs were more likely to have higher apolipoprotein CIII (apoCIII) levels (P<0.05 for each) than patients on no therapy. Elevated TG was associated with disproportionably elevated apoCIII levels in both treatment groups. CONCLUSIONS: In this cross-sectional study of HIV-infected men, either PI or NNRTI therapy elevated levels of TG and apoCIII. Higher concentrations of apoCIII in apoB-containing lipoproteins [very low-density lipoproteins (VLDLs), intermediate density lipoprotein (IDL) and LDLs] have been predictive of an increased incidence of coronary events in clinical trials and more rapid progression of coronary lesions measured by angiography. These findings, on a background of an older population with additional risk factors of smoking and diabetes, portend future atherosclerotic events in these patients.

Low-density lipoprotein particle size, central obesity, cardiovascular fitness, and insulin resistance syndrome markers in obese youths.

OBJECTIVE: (1) To determine the prevalence of small dense low-density lipoprotein (SDLDL) particles in obese youths and (2) to compare youths with SDLDL and large buoyant LDL (LBLDL) subclass phenotypes in total body and abdominal fatness, cardiovascular (CV) fitness, and markers of the insulin resistance syndrome (IRS). DESIGN: For group comparisons, subjects were dichotomized into either SDLDL phenotype group or LBDL phenotype group based on LDL particle size. SUBJECTS: Obese 13 to 16-y-olds (n=80) who had a triceps skinfold greater than the 85th percentile for gender, ethnicity, and age. MEASUREMENTS: LDL particle size, plasma lipids and lipoprotein concentrations, plasma glucose and insulin concentrations, and blood pressures; percentage body fat, visceral adipose tissue (VAT); VO(2) at a heart rate of 170 bpm as an index of CV fitness. RESULTS: The prevalence of the SDLDL phenotype was 54% among the 80 obese youths. Although overall body fatness (ie BMI and percentage body fat) and CV fitness were similar between the two LDL phenotype groups, the SDLDL phenotype group had significantly higher weight, waist circumference and VAT than the LBLDL phenotype group. With respect to the IRS markers, youths with the SDLDL phenotype had significantly higher triacylglycerol (TAG), very low-density lipoprotein cholesterol (VLDLC), apolipoprotein B (apo B), and total cholesterol-to-high-density lipoprotein ratio (TC/HDLC) than youths with the LBLDL phenotype. LDL particle size as a continuous variable was significantly correlated with TAG, VLDLC, apo B, HDLC, and TC/HDLC. Plasma TAG and HDLC concentrations were independent predictors of LDL particle size. CONCLUSION: (1) The SDLDL phenotype was common in obese youths and (2) the relationships of LDL particle size with several of the IRS markers suggested that already in adolescence the expression of the SDLDL phenotype might be an important risk factor for future coronary heart disease mortality and morbidity.

Murine high-fat diet and laser photochemical model of basal deposits in Bruch membrane.

OBJECTIVE: To examine the histologic, histochemical, and ultrastructural changes in Bruch membrane in mice on a high-fat diet with and without laser photochemical injury. METHODS: Five groups of C57BL/6 mice were studied. Group 1 included 2-month-old mice on a normal diet; group 2 included 8-month-old mice on a normal diet; group 3 included 8-month-old mice on a high-fat diet; groups 4 and 5 included 8-month-old mice on a normal diet or high-fat diet, respectively, that underwent laser application of one eye with argon blue laser (488 nm). The mice were killed and plasma lipid levels were measured. The eyes were examined by standard electron microscopy, filipin histochemistry for unesterified cholesterol (UC) and esterified cholesterol (EC), and the osmium-tannic acid-phenylenediamine method for preserving extracellular lipid particles. RESULTS: The plasma cholesterol level was significantly higher in the mice on the high-fat diet than the controls (P<.001). Bruch membrane was thicker in group 2 than group 1 (P =.04) and group 3 had a thicker Bruch membrane than group 2 (P =.003). All eyes in group 3 exhibited accumulation of electron-lucent debris. There was no histochemical and ultrastructural evidence that this material represented accumulated UC or EC. Seven of 9 laser-injured eyes in group 5 accumulated basal laminar deposit (BlamD)-like material in Bruch membrane (P =.02). CONCLUSIONS: Electron-lucent debris accumulates in murine Bruch membrane, and the amount correlates with age and high-fat diet. This debris has some similarities with basal linear deposits, although the debris does not form a discrete layer external to the basement membrane of the retinal pigment epithelium as occurs in basal linear deposits. These deposits do not appear to be UC or EC. Laser photochemical injury of the retinal pigment epithelium may result in the appearance of BlamD-like deposits in eyes with electron-lucent debris. The BlamD-like deposits in this model are similar to the basal laminar deposits that occur in age-related macular degeneration. CLINICAL RELEVANCE: This is an animal model of ultrastructural BlamD-like material in Bruch membrane that is very similar to the deposits that occur in age-related macular degeneration.

Evidence for the in vivo generation of oxidatively modified epitopes in patients with atherosclerotic endothelium.

There is increasing evidence that autoantibodies (AAbs) against oxidatively modified low-density lipoprotein (LDL) are present in humans and may be detected in fasting plasma. Using a standardized immunoassay for the detection of circulating levels of AAbs against malondialdehyde (MDA)-modified LDL, we examined the acute changes in AAb levels during postprandial lipemia in a group of men and women without (n = 28) and with (n = 17) normal endothelium. The presence of atherosclerotic vessel is documented by clinical evidence of coronary artery disease (CAD). In response to the oxidative stress associated with postprandial lipemia, statistically significant reductions in AAb levels were demonstrated at 2 and 4 hours postprandially by paired t test. In patients with atherosclerotic arterial wall, the mean AAb level was reduced to 90.8% of fasting levels (P < .001) after 2 hours and to 90% after 4 hours (P < .01). This acute reduction in AAbs against MDA-LDL appears to be unique to atherosclerotic patients and could not be demonstrated in young controls with healthy blood vessels. In nonatherosclerotic controls, the mean normalized levels during postprandial lipemia were not statistically different from baseline (104.5% at 2 hours and 104.6% at 4 hours). The transient reduction in AAb levels with postprandial lipemia in atherosclerotic patients could be reproduced in a subset of the CAD patients after significant improvement in the lipid profile with weight loss. In patients with atherosclerotic disease, the transient reduction in the level of circulating AAbs reflects either an increased propensity to generate oxidatively modified epitopes or a reduced capacity to remove excess modified epitopes. These data are the first in vivo demonstration of an acute change in the oxidative process during postprandial lipemia.

Visceral adipose tissue and markers of the insulin resistance syndrome in obese black and white teenagers.

OBJECTIVE: To determine the relationships between visceral and general adiposity, cardiovascular fitness, and markers of the insulin resistance syndrome in obese black and white teenagers. RESEARCH METHODS AND PROCEDURES: Cross-sectional survey of 81 obese 13- to 16-year-old youths. Visceral adipose tissue was measured with magnetic resonance imaging, and percentage body fat was measured with dual-energy X-ray absorptiometry. Cardiovascular fitness was assessed with a submaximal treadmill test. Fasting blood samples were analyzed for lipids/lipoproteins and insulin. Resting blood pressure was obtained using an automated cuff. RESULTS: Visceral adipose tissue was significantly correlated with unfavorable levels of: triacylglycerol (r = 0.27, p < 0.05), total cholesterol (r = 0.27, p < 0.05), high-density lipoprotein cholesterol (r = -0.26, p < 0.05), the ratio of total cholesterol/high-density lipoprotein cholesterol (r = 0.42, p < 0.01), low-density lipoprotein cholesterol (r = 0.27, p < 0.05), apolipoprotein B (r = 0.38, p < 0.01), and systolic blood pressure (r = 0.30, p < 0.01). Multiple regression analyses revealed that visceral adipose tissue was more powerful than percentage body fat for explaining variance in lipoproteins (e.g., for the ratio of total cholesterol/high-density lipoprotein cholesterol, r2 = 0.13, p < 0.01, and for systolic blood pressure, r2 = 0.07, p < 0.05). Ethnicity was the most powerful of the demographic predictors for blood lipids (r2 = 0.15 for triacylglycerol with lower levels in blacks; r2 = 0.10 for high-density lipoprotein cholesterol with higher levels in blacks; r2 = 0.06 for the ratio of total cholesterol/high-density lipoprotein cholesterol with lower levels in blacks). Cardiovascular fitness was not retained as a significant predictor of markers of the insulin resistance syndrome. DISCUSSION: Some of the deleterious relationships between visceral adiposity and markers for the insulin resistance syndrome seen in adults were already present in these obese young people.

Ultrastructural changes in Bruch's membrane of apolipoprotein E-deficient mice.

PURPOSE: To examine the histologic and ultrastructural changes in Bruch's membrane (BM) in apolipoprotein E deficient [ApoE(-)] mice in comparison with age-matched control animals. METHODS: Two-month-old (group 1) and 8-month-old (group 2) normal control C57BL/6 mice and 2-month-old (group 3) and 8-month-old (group 4) ApoE(-) mice were studied. All groups of mice were fed a standard rodent diet. The mice were killed, serum lipid levels were determined, and the eyes were ultrastructurally examined using standard techniques to measure the thickness of BM. The area fraction of electron-lucent (EL) particles in BM was quantified using point-counting stereology. RESULTS: The serum cholesterol levels of the ApoE(-) mice were significantly higher than those of the control mice (P = 0.0001). There was a significant thickening and EL particle accumulation in BM associated with age in the control animals. Group 2 had a thicker BM and more EL particle accumulation than group 1 (P = 0.0410 for thickness; P = 0.0042 for particle accumulation). Age-related changes were not seen in ApoE(-) mice; thickness and accumulation were similar in groups 3 and 4 (P = 0.50, thickness; P approximately/= 1.0, accumulation). Significant thickening and accumulation were seen in young ApoE(-) mice (group 3) versus young control animals (group 1; P = 0.008, thickening; P < 0.0001, EL particle accumulation). Group 4 ApoE(-) mice did not have a thicker BM or more EL particles than group 2 control animals (P = 0.2910, thickness; P = 0.35, EL particle accumulation). "Membrane-bounded" material (material between two membranes) was present significantly more frequently in ApoE(-) mice. CONCLUSIONS: ApoE(-) mice exhibit accumulation of EL particles at an earlier age and have more membrane-bounded material in BM than control mice. This material has ultrastructural similarities to basal linear deposit, which accumulates in age-related maculopathy.

Lipid and apolipoprotein levels and distribution in patients with hypertriglyceridemia: effect of triglyceride reductions with atorvastatin.

Atorvastatin is a new hepatic hydroxymethyl glutaryl coenzyme A (HMG-CoA) reductase inhibitor that has been demonstrated to be efficacious in reducing both triglyceride (TG) and cholesterol (CHOL) levels in humans. Twenty-seven (N = 27) patients with primary hypertriglyceridemia (TG > 350 mg/dL) were studied before and after 4 weeks on atorvastatin treatment at a dosage of either 20 (n = 16) or 80 (n = 11) mg/d. The present report examines changes in the plasma levels of several apolipoproteins, including apolipoprotein C-II (apoC-II), apoC-III, and apoE, after atorvastatin. Dose-dependent reductions in both CHOL (20.3% v 43.1%) and TG (26.5% v 45.8%) for the low and high dose, respectively, have been reported in these individuals. In addition to the reductions in apoB commonly associated with the use of HMG-CoA reductase inhibitors, significant reductions in apoE (37% and 49%), apoC-II (28% and 42%), and apoC-III (18% and 30%) were observed with this agent at the 20- and 80-mg/d dosage, respectively. Using fast protein liquid chromatography (FPLC) to fractionate whole plasma according to particle size, the effect of atorvastatin on lipid and apolipoprotein distribution in 20 lipoprotein fractions was also determined. Our results indicate that after 4 weeks on atorvastatin, (1) there was a 2-fold increase in the CHOL content as assessed by the CHOL/apoB ratio for 13 subfractions from very-low-density lipoprotein (VLDL) to small low-density lipoprotein (LDL); (2) there was a statistically significant reduction in the percentage of plasma apoB associated with VLDL-sized particles (30.5% v 26.8%); (3) there was a preferential reduction in plasma apoE from non-apoB-containing lipoproteins with treatment; (4) the losses of apoC-II and apoC-III, on the other hand, were comparable for all lipoprotein fractions; and (5) the fraction of plasma TG associated with HDL was increased after treatment. These changes in lipids and apolipoproteins did not depend on the dose of atorvastatin. There was, on the other hand, a dose-dependent reduction in cholesteryl ester transfer protein (CETP) activity, defined as the percentage of 3H-cholesteryl oleate transferred from high-density lipoprotein (HDL) to LDL. CETP activity was reduced by 10.3% and 26.4% with the low and high dose of atorvastatin. Together, these composition data would be consistent with a net reduction in the number of TG-rich lipoproteins that may be explained by (1) a reduction in VLDL synthesis, (2) a preferential removal of VLDL without conversion to LDL, and (3) a preferential accelerated removal of a subpopulation of LDL.

Apolipoprotein C-III displacement of apolipoprotein E from VLDL: effect of particle size.

ApoC-III and apoE are important determinants of intravascular lipolysis and clearance of triglyceride-rich chylomicrons and VLDL from the blood plasma. Interactions of these two apolipoproteins were studied by adding purified human apoC-III to human plasma at levels observed in hypertriglyceridemic subjects and incubating under specific conditions (2 h, 37 degrees C). As plasma concentrations of apoC-III protein were increased, the contents in both VLDL and HDL were also increased. Addition of apoC-III at concentrations up to four times the intrinsic concentration resulted in the decreasing incremental binding of apoC-III to VLDL while HDL bound increasing amounts without evidence of saturation. No changes were found in lipid content or in particle size of any lipoprotein in these experiments. However, distribution of the intrinsic apoE in different lipoprotein particles changed markedly with displacement of apoE from VLDL to HDL. The fraction of VLDL apoE that was displaced from VLDL to HDL at these high apoC-III concentrations varied among individuals from 20% to 100% its intrinsic level. The proportion of VLDL apoE that was tightly bound (0% to 80%) was found to be reproducible and to correlate with several indices of VLDL particle size. In the group of subjects studied, strongly adherent apoE was essentially absent from VLDL particles having an average content of less than 50,000 molecules of triglyceride. Addition of apoC-III to plasma almost completely displaces apoE from small VLDL particles. Larger VLDL contain tightly bound apoE which are not displaced by increasing concentration of apoC-III.

Effects of exercise training and its cessation on components of the insulin resistance syndrome in obese children.

OBJECTIVE: To determine the effect of exercise training (ET) on components of the insulin resistance syndrome (IRS) in obese children. DESIGN: Randomized, modified cross-over study, with subjects assigned to one of two conditions: (1) 4 months of ET followed by 4 months of no-ET; or (2) 4 months of no-ET followed by 4 months of ET. Measurements were made at three time points: 0, 4 and 8 months. SUBJECTS: 79 obese, but otherwise healthy children (age: 7-11 y, percent fat (%fat) 27-61%). MEASUREMENTS: Plasma lipid and lipoprotein concentrations, plasma insulin and glucose concentrations; %fat; submaximal heart rate (HR) as an index of fitness. EXERCISE TRAINING: ET was offered 5 d/week 40 min/d. For the 73 children who completed 4 months of ET, the mean attendance was 80% (that is, 4 d/week) and the average HR during ET was 157 bpm. RESULTS: Significant (P < 0.05) group x time interactions were found for plasma triglyceride (TG) and insulin concentrations and %fat. The average change for both groups, from just before ET to just after the 4 month ET was -0.24 mmol.l-1 for TG, -25.4 pmol.l-1 for insulin and -1.6 units for %fat. When Group 1 ceased ET, over the following 4 month period the average change for insulin was +26.6 pmol.l-1 and for %fat +1.3 units. CONCLUSION: Some components (plasma TG, insulin, %fat) of the IRS are improved as a result of 4 months of ET in obese children. However, the benefits of ET are lost when obese children become less active.

Los bloqueadores de canales ionicos inhiben la invasion de macrofagos por leishmania SP / Blockers of channels ionics inhibit the invasion of macrophage by leishmania SP

En este trabajo hemos evaluado la interacción de Leishmania con su célula hospedera e macrofagos peritoneales de ratones BALB/c preincubados con inhibidores de canales ionicos. Demostramos que solo la glibenclamida disminuye significativamente la incorporación de los parásitos a su célula hospedera. adicionalmente, la tasa de infección y la carga parasitaria de macrófagos infectados con Leishmania e incubados durante 72 h en presencia de 4-aminopiridina, glibenclamida o amilorida disminuyó significativamente. Al explorar el mecanismo molecular del efecto de la glibenclamida, encontramos que la ausencia de Ca2+ extracelualr revierte la disminución d ela fagocitosis encontrada en los viales experimentales. Este hecho sugiere que parte de los efectos de esta droga s edeben a una acción directa sobre la célula hispedera. Por su parte, la reducción de la tasa de infección y de la carga parasitaria evidenciada a las 72 horas no es revertida por la ausencia del Ca extracelular ni por aumentos intracelulares de Ca2+ de las organelas intracelulares. Este hecho sugiere que los efectos a largo plazo de la glibenciamida pudieran ser debidos a acciones directas de la droga sobre el parásito intracelular. Estos resultados sugieren que el funcionamiento de las estructuras sensibles a estos inhibidores de canales iónios son fundamentales para el mantenimiento de la homeostasis y la supervivencia del parásito en los diferentes ambientes en los cuales se lleva a cabo su ciclo de vida. es importante el hecho de que los amastigotes son particularmente sensibles a algunas de las drogas como la glibenclamida, que en otros tejidos y organismos modula el funcionamiento de canales de potasio cuya función esta intrínsecamente relacionada con el estado metabólico de la célula

Visceral adipose tissue and cardiovascular risk factors in obese children.

OBJECTIVE: In adults visceral adipose tissue (VAT) has been shown to be more highly correlated with cardiovascular (CV) risk factors than are other measures of adiposity such as subcutaneous abdominal adipose tissue (SAAT), percent body fat (%BF), or total body fat mass (TFM). We examined the relations between these measures of fatness and CV risk factors in obese children. STUDY DESIGN: Subjects were 64 obese (27% to 61% BF) children (24 black girls, 19 white girls, 11 black boys, 10 white boys) aged 7 to 11 years. VAT and SAAT were measured with magnetic resonance imaging. TFM and %BF were determined with dual x-ray absorptiometry. Hierarchical stepwise multiple regression analyses were used to determine the proportions of variance in CV risk factors explained by the demographic and adiposity measures. RESULTS: VAT but not SAAT, %BF, or TFM explained a significant proportion of the variance (r2 range = 0.10 to 0.21) in several lipid/lipoprotein risk factors including triacylglycerols, high-density lipoprotein cholesterol, the ratio of total cholesterol to high-density lipoprotein cholesterol, and low-density lipoprotein particle size. CONCLUSION: Many of the deleterious relations between VAT and lipid/lipoprotein risk factors seen in adults were already present in this sample of obese children.

An efficient chromatographic system for lipoprotein fractionation using whole plasma.

We have validated a semi-automatic procedure for the efficient isolation of plasma lipoproteins from 300 microl of whole plasma (actual injection volume 200 microl) by Fast Phase Liquid Chromatography (FPLC). Modified enzymatic assays were established to allow the determination of low concentrations (1-20 mg/dl) of triglycerides and cholesterol using the Beckman CX-5 Autoanalyzer. The sum of the cholesterol contents in the fractions corresponding to low density (LDL) and high density lipoprotein (HDL) can be demonstrated to be highly correlated to values obtained with dextran sulfate/MgCl2 precipitation for HDLc (slope = 0.98, r2 = 0.997) and ultracentrifugation (beta-quant) for LDLc (slope = 1.03, r2 = 0.988). Using pure lipoprotein fractions isolated by ultracentrifugation, linear ranges of detection for HDLc and HDL apoA-I were performed at 18-95 mg/dl and 59-262 mg/dl, respectively. The ranges for LDLc were 41-435 mg/dl and 21-280 mg/dl for LDL apoB. The mean (range) fractional standard deviations for quadruplicate runs for 15 individual plasma samples ranging widely in lipoprotein concentrations were 0.97 (0.29-2.86%) for LDLc (range: 101.5-258.5 mg/dl), 3.67 (0.62-14.11%) for HDLc (range: 27.1-85.1 mg/dl) and 2.19 (0.16-6.56%) for VLDL-TG (range: 6.1-515.0 mg/dl).

Kinetics of retinyl esters during postprandial lipemia in man: a compartmental model.

Orally ingested vitamin A (retinol) is incorporated into intestinal chylomicrons (CHYLO) in the form of retinyl esters (RE) along with newly absorbed dietary triglycerides (TG). As the intestinal lipoproteins undergo hydrolysis in the circulation, the majority of the RE remain with the secreted intestinal particles and have been used as a marker for intestinally derived lipoproteins during the early phase of the postprandial state. A multicompartmental model was developed for the kinetics of RE during postprandial lipemia in individuals with normal lipid levels (n = 16) and in patients with hyperlipidemia (n = 44). The assumptions used in the development of the model are presented in this report. Some of the key findings include (1) as much as 50% of the newly synthesized RE may be secreted by the intestine as very-low-density lipoprotein (VLDL)-sized particles of S(f) 20 to 400 following consumption of a test meal containing a moderate amount of fat (20 to 30 g); (2) in most individuals, approximately 50% of the RE secreted in S(f) greater than 400 are converted to smaller, less buoyant fractions, and 50% are irreversibly removed directly from the plasma; (3) as much as 5% to 20% of the ingested retinol may be secreted as small intestinal lipoproteins with the buoyance of low-density lipoprotein (LDL) in some individuals; and (4) less than 5% of RE flux through S(f) 20 to 400 is converted to S(f) less than 20, and the primary catabolic pathway for RE in this fraction is direct uptake. Comparable estimates can be obtained for the kinetic parameters when repeat studies are made in the same subjects under comparable conditions.