Antoni Castro

Circulating Omentin as a Novel Biomarker of Endothelial Dysfunction

Omentin is a novel soluble lectin expressed mainly in the stromal‐vascular cells from visceral adipose tissue with vasodilator effect in isolated blood vessels. To gain insight in the relationship between obesity and cardiovascular risk factors, we aimed to explore the interaction among circulating omentin, metabolic parameters, and endothelial function. Circulating omentin (enzyme‐linked immunosorbent assay) was studied in 248 white men (148 with normal glucose tolerance (NGT) and 100 with impaired glucose tolerance (IGT)). Insulin sensitivity was measured using the frequently sampled intravenous glucose tolerance test. Vascular reactivity was measured by high‐resolution ultrasound of the brachial artery. Circulating omentin concentration was significantly increased in lean compared with overweight and obese subjects (53.7 ± 16.9 vs. 45.2 ± 16.8 and vs. 40.1 ± 15.5 ng/ml, P < 0.0001). Circulating omentin concentration correlated with age, BMI, waist‐to‐hip ratio (WHR), percentage of fat mass, systolic and diastolic blood pressure, endothelium‐dependent and independent vasodilation (EDV and EIV), C‐reactive protein, and interleukin‐6 (IL‐6). In IGT subjects, circulating omentin concentration also correlated with insulin sensitivity, although this association did not remain significant after controlling for BMI. In a multiple linear regression analysis, circulating omentin concentration (P = 0.01), systolic blood pressure (P = 0.04), and BMI (P = 0.04) contributed independently to EDV after controlling for age and C‐reactive protein in IGT subjects. In NGT subjects, only circulating omentin concentration (P = 0.01) was significantly associated with EDV. In conclusion, circulating omentin concentration could be a useful marker of endothelial function.

G Protein β3 Gene Variant, Vascular Function, and Insulin Sensitivity in Type 2 Diabetes

A common polymorphism (825 C/T) in exon 10 of the GNB3 gene, that encodes for the β-3 subunit, has been associated with different degrees of activation of heterotrimeric guanine nucleotide binding proteins (G proteins). Many hormones and neurotransmitters use specific receptors that interact noncovalently with G proteins in the transmembrane signaling process. Among them, insulin uses an inhibitory G protein–sensitive mechanism that is involved in metabolic and vascular events, leading to enhanced glucose transport and vasodilation. We hypothesized differences in peripheral and vascular insulin sensitivity according to GNB3 gene polymorphism in type 2 diabetic patients. To address this issue, we used an intervention-optimization protocol to examine whether diabetic patients with the variant show a different response in terms of insulin-sensitivity. Interindividual differences in baseline insulin sensitivity and vascular dysfunction (vasodilatory response to glyceryl trinitrate) were not attributable to this polymorphism of the GNB3 gene. However, in contrast to normal homozygotes, insulin sensitivity (SI) significantly improved ( P =0.01) in carriers of the 825T variant. Parallel to these findings, stimulated C-peptide tended to decrease, and the response to glyceryl trinitrate significantly improved ( P =0.004) among 825T carriers. Body mass index, systolic and diastolic blood pressure, heart rate, or serum lipid levels did not significantly change in either group. Our findings suggest an effect of GNB3 gene polymorphism on important phenotypic variations in type 2 diabetes mellitus. The GNB3 gene polymorphism might be an example of pharmacogenetics, with the underlying etiological genetic defect altering the response to treatment.

Alpha Defensins 1, 2, and 3 Potential Roles in Dyslipidemia and Vascular Dysfunction in Humans

Objectives—&agr;-Defensins are natural antibiotics made by neutrophils that have been reported to modulate cholesterol metabolism and vascular function; however, their role in vivo remains largely unknown. We hypothesized that &agr;-defensins 1 to 3 (DEFA1–3) are associated with serum lipids and vascular reactivity in humans. Methods and Results—One hundred thirteen apparently-healthy White men, participants in a prospective study of cardiovascular risk factors, were assessed for a lipid profile, insulin sensitivity (SI, frequently-sampled intravenous glucose tolerance test), and non-stressed circulating DEFA1–3 (ELISA). In a subset of 52 subjects, vascular reactivity (high-resolution ultrasound of the brachial artery) was also assessed. Subjects in the highest quartile for plasma DEFA1–3 were found to be leaner and more insulin sensitive, and to have significantly reduced total and LDL-cholesterol, compared with subjects in the lowest quartile for circulating DEFA1–3 (P<0.0001 to P=0.002 for linear trend ANOVA). The associations with serum lipids persisted after adjustment for age, body mass index, insulin sensitivity, and smoking (which was associated with reduced plasma DEFA1–3 concentrations). Finally, endothelium-independent vasodilation increased with increasing circulating DEFA1–3 (P=0.003) and this association was not explained by age, body mass index, serum cholesterol, insulin sensitivity, or smoking. Conclusions—Circulating DEFA1–3 are associated with serum cholesterol and vascular reactivity in humans. &agr;-Defensins may have clinical implications in patients with either hypercholesterolemia or vascular dysfunction.

Leptin and adiponectin, but not IL18, are related with insulin resistance in treated HIV-1-infected patients with lipodystrophy.

Leptin, adiponectin and IL18 are adipokines related with obesity, insulin resistance and dyslipidemia in the general population. Treated HIV-1-infected patients with lipodystrophy may develop insulin resistance and proatherogenic dyslipidemia. We assessed the relationship between plasma adipokine levels, adipokine genetics, lipodystrophy and metabolic disturbances. Plasma leptin, adiponectin and IL18 levels were assessed in 446 individuals: 282 HIV-1-infected patients treated with antiretroviral drugs (132 with lipodystrophy and 150 without) and 164 uninfected controls (UC). The LEP2410A>G, LEPRQ223R, ADIPQ276G>T, ADIPOR2-Intron5A>G and IL18-607C>A polymorphisms were validated by sequencing. Leptin levels were higher in UC than in HIV-1-infected, either with or without lipodystrophy (p<0.001 for both comparisons) and were lower in patients with lipodystrophy compared with those without lipodystrophy (p=0.006). In patients with lipodystrophy, leptin had a positive correlation with insulin and with HOMA-IR. Adiponectin levels were non-significantly different in UC and HIV-1-infected patients. Patients with lipodystrophy had lower adiponectin levels than non-lipodystrophy subjects (p<0.001). In patients with lipodystrophy, adiponectin was negatively correlated with insulin, HOMA-IR and triglycerides. Plasma IL18 levels were higher in HIV-1-infected patients compared with UC (p<0.001), and no differences were found according to the presence of lipodystrophy. In patients with lipodystrophy there was a negative correlation between IL18 levels and LDLc. Genetic analyses indicated no significant associations with lipodystrophy nor with insulin resistance or with lipid abnormalities. In conclusion, HIV-1-infected patients have reduced plasma leptin levels. This reduction is magnified in patients with lipodystrophy whose adiponectin levels were lower than that of non-lipodystrophy subjects. Plasma IL18 levels are increased in infected patients irrespective of the presence of lipodystrophy. The polymorphisms assessed are not associated with lipodystrophy or metabolic disturbances in treated HIV-1-infected patients.

Cocoa, Hazelnuts, Sterols and Soluble Fiber Cream Reduces Lipids and Inflammation Biomarkers in Hypertensive Patients: A Randomized Controlled Trial

Background Cocoa, mixed with other food ingredients, intake can have beneficial effects on cardiovascular disease (CVD) biomarkers. We compared the effects of 4 cocoa cream products on some of these biomarkers. Methods and Findings In this multi-centered, randomized, controlled, double-blind, parallel trial, volunteers (n = 113; age range: 43–65 years) who were pre-hypertensive, stage-1 hypertensive and hypercholesterolemic received one of 4 cocoa cream products (13 g/unit; 1 g cocoa/unit, 6 units/d; 465 Kcal/d) added to a low saturated fat diet for 4 weeks. The groups were: A) (n = 28), cocoa cream considered as control; B) (n = 28), cocoa+hazelnut cream (30 g/d hazelnuts); C) (n = 30), cocoa+hazelnuts+phytosterols (2 g/d); and D) (n = 27), cocoa+hazelnuts+phytosterols+soluble fiber (20 g/d) the patented “LMN product”. Primary outcome measures were BP, LDL-c, apolipoprotein B-100 (Apo B), ApoB/ApoA ratio, oxidized LDL (oxLDL) and high-sensitive C-reactive protein (hsCRP) determined at baseline and post-cocoa cream product intake. Statistical analysis used was ANCOVA or mixed models (in case of repeated measurements), with baseline observation included as a covariate. After 4 weeks, compared to product A, product C reduced LDL-c by 11.2%, Apo B by 8.1% and ApoB/ApoA ratio by 7.8% (P = 0.01). LMN decreased LDL-c by 9.2%, Apo B-100 by 8.5%, ApoB/ApoA ratio by 10.5%, hsCRP by 33.4% and oxLDL by 5.9% (P = 0.01). Surprisingly, even “control” product A reduced systolic BP (−7.89 mmHg; 95%CI: −11.45 to −4.3) and diastolic BP (−5.54 mmHg; 95%CI: −7.79 to −3.29). The BP reductions were similar with the other 3 products. Limitations of the study are that the trial period was relatively short and that a better “BP control” product would have been preferable. Conclusion The creams (particularly the LMN) have anti-inflammatory and antioxidant effects in addition to lowering LDL-c, Apo B and ApoB/ApoA ratio. Thus, the soluble fiber effects amplified with sterols (as contained in the cocoa creams) provide new dietary therapeutic perspectives. Trial Registration Clinicaltrials.gov NCT00511420

Lipodystrophy and Insulin Resistance in Combination Antiretroviral Treated HIV-1―Infected Patients: Implication of Resistin

Background:Little information is available with respect to the involvement of resistin in lipodystrophy and metabolic disturbances in HIV-1-infected patients treated with combination antiretroviral therapy (cART). We determined whether the resistin (rest) −420C>G single-nucleotide polymorphism and plasma resistin are associated with the development of lipodystrophy and metabolic disturbances in HIV-1-infected patients treated with cART. Methods:The study group comprised 299 HIV-1-infected patients treated with a stable cART for at least 1 year (143 with lipodystrophy and 156 without) and 175 uninfected controls. Anthropometric, clinical, and metabolic variables were determined. Homeostasis model assessment for insulin resistance was used to evaluate insulin resistance. Plasma resistin levels were determined by enzyme-linked immunosorbent assay. The rest −420C>G was assessed using restriction fragment length polymorphism. Student t test, 1-way and 2-way analysis of variance, χ2 test, and Pearson and Spearman correlations were performed for statistical analysis. Results:Genotypes containing the rest −420G variant allele were significantly more common in HIV-1-infected patients without lipodystrophy compared with those with lipodystrophy (P = 0.037). Infected patients had significantly greater plasma resistin levels than uninfected controls (P < 0.001). Among infected patients, plasma resistin levels were significantly lower in patients with lipodystrophy with respect to those without (P = 0.034). In infected patients, plasma resistin levels had a significant positive correlation with insulin and homeostasis model assessment for insulin resistance: P < 0.001 and P = 0.002 in the lipodystrophy subset and P = 0.002 and P = 0.03 in the nonlipodystrophy subset, respectively. Conclusions:In our cohort of white Spaniards, the rest −420C>G single-nucleotide polymorphism may be associated with cART-related lipodystrophy. Plasma resistin correlates with insulin resistance in infected patients with and without lipodystrophy.

APOH is increased in the plasma and liver of type 2 diabetic patients with metabolic syndrome

OBJECTIVE To assess the association of APOH with metabolic and cardiovascular risk markers in type 2 diabetic patients. METHODS In a cohort of 169 type 2 diabetic subjects, plasma levels of APOH, antibodies anti-APOH, lipoprotein subfractions, oxidation, inflammatory and insulin resistance markers and the Trp316Ser and Val247Leu variations in the APOH gene were analyzed. Apo H mRNA levels and protein content were measured in hepatic and adipose tissue (subcutaneous and visceral) samples obtained during bariatric surgery from three diabetics who fulfilled metabolic syndrome (MS) criteria and three non-diabetic, non-MS. RESULTS APOH plasma levels were significantly associated with triglycerides (p<0.001), all the components of triglyceride-rich lipoproteins (p<0.001) and RBP4 (p<0.001) levels. APOH was higher in type 2 diabetic patients with MS (p=0.003) and with clinical evidence of macrovascular disease (p=0.012). The Trp316Ser and Val247Leu APOH gene variants did not modulate APOH plasma values. Neither Apo H mRNA nor protein was detected in the adipose tissue. Liver from patients with diabetes and MS showed a significant increase of both Apo H mRNA and protein respect to the non-diabetic, non-MS patients. CONCLUSION APOH plasma concentrations are strongly associated to MS alterations and vascular disease in type 2 diabetic patients and could be considered as a clinical marker of cardiovascular risk. The enhanced APOH levels in these patients are due to an increased liver synthesis. If APOH plays a major causal role in macrovascular lesions associated to diabetes and MS need further studies.

Opposite relationship between circulating soluble CD14 concentration and endothelial function in diabetic and nondiabetic subjects

Recent prospective studies indicate endothelial dysfunction and increased risk for cardiovascular events in patients with serological evidence of multiple infections. Soluble CD14 (sCD 14) plays a key role in the neutralization of lipopolysaccharide (LPS), a well-established bacterial product inducing endothelial dysfunction. Insulin resistance was recently identified as a significant factor influencing circulating sCD 14 concentration. Thus, we investigated the association of circulating sCD14 and endothelial dysfunction in subjects with well-established insulin resistance (patients with type 2 diabetes, n = 40) compared to control non-diabetic subjects (n = 100). To further explore the underlying mechanisms, we also analysed C-reactive protein and circulating NO2-/NO3- and cyclic GMP in the diabetic group. Serum sCD 14 concentration (ELISA) was found to be differently associated with endothelium-dependent vasodilatation (EDVD, high-resolution ultrasound) in diabetic and non-diabetic subjects. In nondiabetic subjects, serum sCD14 and C-reactive protein correlated negatively with EDVD (r = -0.21, p = 0.03, and r = -0.21, p = 0.03, respectively). In a partial correlation analysis, these associations remained significant after controlling for age and weight (sCD 14 and EDVD, r = -0.23, p = 0.023; C-reactive protein and EDVD, r = -0.21, p = 0.03; sCD14 and C-reactive protein, r = 0.30, p = 0.002). In contrast, sCD 14 was positively associated with EDVD in type 2 diabetic patients (r = 0.37, p = 0.019,). Interestingly, sCD14 was also associated with NO2-/NO3- in this group (r = 0.62, p = 0.001, n = 22). EDVD also correlated with cyclic GMP (r = 0.47, p = 0.03, n = 22). In summary, circulating sCD 14 is associated with endothelial function. While in non-diabetic subjects sCD14 behaves as an acute phase reactant, its role in type 2 diabetic patients should be further clarified. These findings need to be confirmed in further studies with larger number of patients.

Nuclear Magnetic Resonance Lipoprotein Subclasses and the APOE Genotype Influence Carotid Atherosclerosis in Patients with Systemic Lupus Erythematosus

Objective. Patients with systemic lupus erythematosus (SLE) have accelerated atherosclerosis. Since the conventional lipid profile (total plasma cholesterol, triglycerides, low and high density lipoprotein cholesterol) is not consistently altered in SLE, we hypothesized that investigation of lipoprotein subclasses would improve prediction of risk of atherosclerosis in these patients. Methods. As a quantitative index of atherosclerosis, we measured the carotid intima-media thickness (IMT) in 68 patients with SLE and related the atherosclerosis to a detailed lipoprotein profile generated using nuclear magnetic resonance (NMR). We measured the cholesterol transported by the pool of remnant lipoproteins (RLPc) and evaluated the modulatory effect of the APOE genotype on the lipoprotein subclass profile and atherosclerosis associated with SLE. Results. Circulating lipoprotein remnant particles [RLPc and intermediate density lipoprotein (IDL)] were positively correlated with IMT, and among them, the indicator that explained 20.2% of the variability in carotid atherosclerosis measured in these patients was IDL, as assessed by NMR. Carriers of the APOE2 allele were at increased risk due to a significant accumulation of IDL particles. Conclusion. Lipoprotein subclasses are more associated with subclinical atherosclerosis in patients with SLE than the lipid variables that are routinely measured. The IDL fraction, which is significantly modulated by the APOE genotype, is the most strongly, significantly, and positively correlated with IMT.

The alarm secretory leukocyte protease inhibitor increases with progressive metabolic dysfunction

BACKGROUND Secretory leukocyte protease inhibitor (SLPI) is an alarm antiprotease secreted by neutrophils and mucous membranes that potently inhibits the inflammatory cascade; however, the role of SLPI in human disease remains largely unknown. We hypothesized that SLPI is related to chronic low-grade inflammatory diseases, such as metabolic syndrome (MS) or type-2 diabetes (T2DM). METHODS We examined associations between circulating SLPI (ELISA) and quantitative traits of MS (ATPIII criteria) in 261 Caucasian men with various degrees of metabolic dysfunction. Subjects had neither MS nor T2DM (n=140), either diagnosis (n=44) or both diagnoses (n=77). RESULTS Circulating SLPI increased with progressive metabolic dysfunction, with a mean increase of 4.4 ng/ml (95% IC 2.4 to 6.3 ng/ml; p<0.001) for each unit increase in the criteria used to define MS. Circulating SLPI showed independent associations with uric acid [β=5.1 (95% CI 3.4 to 6.7), p<0.00001], serum lipids, pulse pressure and inflammatory markers. CONCLUSIONS Circulating SLPI increases with progressive metabolic dysfunction and is related to metabolic and inflammatory parameters in men.