Emerging therapies for raising high-density lipoprotein cholesterol (HDL-C) and augmenting HDL particle functionality

High-density lipoprotein (HDL) particles are highly complex polymolecular aggregates capable of performing a remarkable range of atheroprotective functions. Considerable research is being performed throughout the world to develop novel pharmacologic approaches to: (1) promote apoprotein A-I and HDL particle biosynthesis; (2) augment capacity for reverse cholesterol transport so as to reduce risk for the development and progression of atherosclerotic disease; and (3) modulate the functionality of HDL particles in order to increase their capacity to antagonize oxidation, inflammation, thrombosis, endothelial dysfunction, insulin resistance, and other processes that participate in arterial wall injury. HDL metabolism and the molecular constitution of HDL particles are highly complex and can change in response to both acute and chronic alterations in the metabolic milieu. To date, some of these interventions have been shown to positively impact rates of coronary artery disease progression. However, none of them have as yet been shown to significantly reduce risk for cardiovascular events. In the next 3-5 years a variety of pharmacologic interventions for modulating HDL metabolism and functionality will be tested in large, randomized, prospective outcomes trials. It is hoped that one or more of these therapeutic approaches will result in the ability to further reduce risk for cardiovascular events once low-density lipoprotein cholesterol and non-HDL-cholesterol targets have been attained.

Occult hepatitis B infection in the immigrant population of Sicily, Italy

In Italy, about 7 % of the resident population is represented by immigrants originating from geographic regions at high endemicity for hepatitis B virus infection. This study aims to assess the prevalence of occult HBV infection (OBI) including the identification of HBV-genotypes in a population of immigrants serologically negative for hepatitis B surface antigen (HBsAg). Between May 2006 and May 2010, 339 immigrants were tested for markers of HBV, hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infections. HBV-DNA was tested by using nested-PCR assays on three different genetic region. HBV-DNA was detected in plasma samples of 11/339 (3.2 %) patients. Most of them had no serological markers of HBV infection, 3/58 (5.2 %) were anti-HBc-alone, and 4/13 (30.8 %) were anti-HIV positive. HIV positivity was the only factor independently associated with the higher probability of observing OBI (OR = 16.5, p < 0.001). No HCV co-infected patients were found. Genotype D was detected in 9/11 (81.8 %) OBI cases, while the remaining two (18.2 %) were classified as genotype E. Although OBI was found at lower rate than expected among immigrants from highly endemic countries, anti-HBc alone positivity was confirmed as a sentinel marker of occult HBV infection. Nevertheless, a marked heterogeneity of HBV markers was found among HBV-DNA positive subjects. Our finding evidenced the predominance of HBV-genotype D viral strains among OBI cases, also in those from geographical areas where overt HBV infections are mainly sustained by viral genotypes other than D.

Elevated blood Hsp60, its structural similarities and cross-reactivity with thyroid molecules, and its presence on the plasma membrane of oncocytes point to the chaperonin as an immunopathogenic factor in Hashimoto's thyroiditis

The role Hsp60 might play in various inflammatory and autoimmune diseases is under investigation, but little information exists pertaining to Hashimoto's thyroiditis (HT). With the aim to fill this gap, in the present work, we directed our attention to Hsp60 participation in HT pathogenesis. We found Hsp60 levels increased in the blood of HT patients compared to controls. The chaperonin was immunolocalized in thyroid tissue specimens from patients with HT, both in thyrocytes and oncocytes (Hurthle cells) with higher levels compared to controls (goiter). In oncocytes, we found Hsp60 not only in the cytoplasm but also on the plasma membrane, as shown by double immunofluorescence performed on fine needle aspiration cytology. By bioinformatics, we found regions in the Hsp60 molecule with remarkable structural similarity with the thyroglobulin (TG) and thyroid peroxidase (TPO) molecules, which supports the notion that autoantibodies against TG and TPO are likely to recognize Hsp60 on the plasma membrane of oncocytes. This was also supported by data obtained by ELISA, showing that anti-TG and anti-TPO antibodies cross-react with human recombinant Hsp60. Antibody-antigen (Hsp60) reaction on the cell surface could very well mediate thyroid cell damage and destruction, perpetuating inflammation. Experiments with recombinant Hsp60 did not show stimulation of cytokine production by peripheral blood mononuclear cells from HT patients. All together, these results led us to hypothesize that Hsp60 may be an active player in HT pathogenesis via an antibody-mediated immune mechanism.

HLA and killer cell immunoglobulin-like receptors influence the natural course of CMV infection

BACKGROUND

Natural killer (NK) cells provide a major defense against cytomegalovirus (CMV) infection through the interaction of their surface receptors, including the activating and inhibitory killer immunoglobulin-like receptors (KIRs), and human leukocyte antigens (HLA) class I molecules. This study assessed whether the KIR and HLA repertoire may influence the risk of developing symptomatic or asymptomatic disease after primary CMV infection in the immunocompetent host.

METHODS

Sixty immunocompetent patients with primary symptomatic CMV infection were genotyped for KIR and their HLA ligands, along with 60 subjects with a previous asymptomatic infection as controls.

RESULTS

The frequency of the homozygous A haplotype (only KIR2DS4 as activating KIR) was higher in symptomatic patients than controls (30% vs 12%, respectively; odds ratio [OR] = 3.24; P = .01). By logistic regression, the risk of developing symptomatic disease was associated with the homozygous A haplotype and the HLABw4(T) allele. Combining the 2 independent variables, we found that 37 out of 60 (62%) symptomatic patients but only 18 out of 60 (30%) of controls possessed the homozygous A haplotype or the HLABw4(T) allele with a highly significant OR (OR = 3.75, P < .0005).

CONCLUSIONS

Immunocompetent subjects carrying the homozygous A haplotype or the HLABw4(T) allele are at higher risk of developing symptomatic disease after primary CMV infection.

Effects of lipid-lowering drugs on high-density lipoprotein subclasses in healthy men-a randomized trial

CONTEXT AND OBJECTIVE

Investigating the effects of lipid-lowering drugs on HDL subclasses has shown ambiguous results. This study assessed the effects of ezetimibe, simvastatin, and their combination on HDL subclass distribution.

DESIGN AND PARTICIPANTS

A single-center randomized parallel 3-group open-label study was performed in 72 healthy men free of cardiovascular disease with a baseline LDL-cholesterol of 111±30 mg/dl (2.9±0.8 mmol/l) and a baseline HDL-cholesterol of 64±15 mg/dl (1.7±0.4 mmol/l). They were treated with ezetimibe (10 mg/day, n = 24), simvastatin (40 mg/day, n = 24) or their combination (n = 24) for 14 days. Blood was drawn before and after the treatment period. HDL subclasses were determined using polyacrylamide gel-tube electrophoresis. Multivariate regression models were used to determine the influence of treatment and covariates on changes in HDL subclass composition.

RESULTS

Baseline HDL subclasses consisted of 33±10% large, 48±6% intermediate and 19±8% small HDL. After adjusting for baseline HDL subclass distribution, body mass index, LDL-C and the ratio triglycerides/HDL-C, there was a significant increase in large HDL by about 3.9 percentage points (P<0.05) and a decrease in intermediate HDL by about 3.5 percentage points (P<0.01) in both simvastatin-containing treatment arms in comparison to ezetimibe. The parameters obtained after additional adjustment for the decrease in LDL-C indicated that about one third to one half of these effects could be explained by the extent of LDL-C-lowering.

CONCLUSIONS

In healthy men, treatment with simvastatin leads to favorable effects on HDL subclass composition, which was not be observed with ezetimibe. Part of these differential effects may be due to the stronger LDL-C-lowering effects of simvastatin.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00317993.

Liraglutide decreases carotid intima-media thickness in patients with type 2 diabetes: 8-month prospective pilot study

BACKGROUND

Liraglutide, a long-acting glucagon-like peptide-1 (GLP-1) analog, has several non- glycemic properties, but its effect on carotid intima-media thickness (IMT), a recognized marker of subclinical atherosclerosis, is still unknown.

METHODS

A prospective study of 8 months duration in 64 patients with type-2 diabetes and no prior history of coronary artery disease evaluated whether adding liraglutide to metformin affects carotid IMT, measured by color doppler ultrasound.

RESULTS

After 8 months, fasting glucose decreased by 2.1 mmol/l and HbA1c by 1.9% (p < 0.01 for all). Liraglutide reduced total-cholesterol and triglycerides by 10%, and LDL-cholesterol by 19%, whereas HDL-cholesterol increased by 18% (p < 0.01 for all lipid changes). Carotid IMT decreased from 1.19 ± 0.47 to 0.94 ± 0.21 mm (p < 0.01). Yet, changes in carotid IMT did not correlate with changes in any other variable studied.

CONCLUSIONS

Liraglutide decreases carotid IMT after 8 months treatment independently of its effect on plasma glucose and lipids concentrations.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01715428.

A review of the cardiovascular and anti-atherogenic effects of ghrelin

Ghrelin is a peptide hormone produced mainly in the stomach that has widespread tissue distribution and diverse hormonal, metabolic and cardiovascular activities. The circulating ghrelin concentration increases during fasting and decreases after food intake. Ghrelin secretion may thus be initiated by food intake and is possibly controlled by nutritional factors. Lean subjects have increased levels of circulating ghrelin compared with obese subjects. Recent reports show that low plasma ghrelin is associated with elevated fasting insulin levels, insulin resistance and type 2 diabetes mellitus. Factors involved in the regulation of ghrelin secretion have not yet been defined; however, it is assumed that blood glucose levels represent a significant regulator. Recent evidence indicates that ghrelin can increase myocardial contractility, enhance vasodilatation, and has protective effect from myocardial damage. It has been shown that ghrelin may improve cardiac function through growth hormone (GH)-dependent mechanisms but there is also evidence to suggest that ghrelin's cardioprotective activity is independent of GH. Recent data demonstrate that ghrelin can influence key events in atherogenesis. Thus, ghrelin may be a new target for the treatment of some cardiovascular diseases. In this review, we consider the current literature focusing on ghrelin as a potential antiatherogenic agent in the treatment of various pathophysiological conditions.

PAP/HIP protein is an obesogenic factor

In this article we report the obesogenic role of the acute phase protein PAP/HIP. We found that the transgenic TgPAP/HIP mice develop spontaneous obesity under standard nutritional conditions, with high levels of glucose, leptin, and LDL and low levels of triglycerides and HDL in blood. Accordingly, PAP/HIP-deficient mice are skinny under standard nutritional conditions. We also found that expression of PAP/HIP is induced in intestinal epithelial cells in response to gavage with olive oil and this induction is AG490 sensitive. We demonstrated that incubation of 3T3-L1 preadipocytes with a low concentration as 1 ng/ml of recombinant PAP/HIP results in accelerated BrdU incorporation in vitro. PAP/HIP-dependent adipocytes growth is sensitive to the MEK inhibitor U0126. Finally, patients with severe obesity present higher blood levels of PAP/HIP than non-obese control individuals. Altogether our data suggest that PAP/HIP could be a mediator of fat tissue development, released by the intestine and induced by the presence of food into the gut.

The health of irregular and illegal immigrants: analysis of day-hospital admissions in a department of migration medicine

It is difficult to trace full details of the path which irregular or illegal immigrants follow when seeking assistance in the network of the various hospital departments and health structures. The aim of this work was to analyze the health needs of immigrant people by reviewing the types of treatment given to them in the day-hospital of our Department of Migration Medicine. Our study analyzed day-hospital admissions between 2003 and 2009. The patient charts used for managing day-hospital activity were adopted in 2002 in conformity with the "OSI project". From these it is possible to draw up a scale picture of the distribution of each pathology in the immigrant population. The sample population consisted of 1,758 subjects, representing 7.4% of potential users. More than half came from Africa, followed by Asia, and then Europe. Gastroenterological diseases ranked first, with dyspeptic syndromes most frequently diagnosed. Infections and parasitic diseases ranked second, and the most frequent diagnoses were sexually transmitted diseases. Third were diseases of the genitourinary system. Metabolic disorders ranked fourth, among them, more than half of the cases were of diabetes mellitus, in patients from south-east Asia. Diseases of the circulatory system were sixth, with hypertension the most frequent pathology. Our data confirm a marked persistence of the phenomenon known as the "healthy immigrant effect" in these types of patients, as well as the prominent role played by "social determinants" in conditioning the health of immigrants, particularly in the case of some infectious diseases.

Serum low density lipoprotein subclasses in asthma

BACKGROUND

The levels of serum low-density lipoproteins (LDL) have been implicated in the inflammatory cascade in a murine model of asthma. Recent findings suggest that LDL may modulate the inflammatory state of the asthmatic airways in humans.

OBJECTIVE

We explored whether LDL subclasses are associated with the occurrence and severity of asthma.

METHODS

24 asthmatics (M/F: 11/13) and 24 healthy individuals, with normal BMI and absence of metabolic syndrome, matched for age and gender. Serum concentrations of LDL subclasses were distributed as seven bands (LDL-1 and -2 defined as large, least pro-inflammatory LDL, and LDL-3 to -7 defined as small, most pro-inflammatory LDL), using the LipoPrint(©) System (Quantimetrix Corporation, Redondo Beach, CA, USA).

RESULTS

LDL-1 was similar in the two groups (56 ± 16% vs. 53 ± 11, p = NS), while LDL-2 was significantly lower in asthmatics as compared to controls (35 ± 8% vs. 43 ± 10%, p = 0.0074). LDL-3 levels were two-fold higher in the asthmatics, but the difference did not reach the statistical significance (8 ± 7.3% vs. 4 ± 3%, p = NS). Smaller subclasses LDL-4 to LDL-7 were undetectable in controls. In asthmatics, LDL-1 was positively associated with VC% predicted (r = +0.572, p = 0.0035) and FEV1% predicted (r = +0.492, p = 0.0146). LDL-3 was inversely correlated with both VC% predicted (r = -0.535, p = 0.0071) and FEV1% predicted (r = -0.465, p = 0.0222).

CONCLUSIONS

The findings of this pilot study suggest a role of LDL in asthma, and advocate for larger studies to confirm the association between asthma and dyslipidemia.

Emerging approaches for the treatment of hypertriglyceridemia

Hypertriglyceridemia is frequent in diabetic and obese subjects, who are at increased risk for cardiovascular diseases (CVD). Increased triglycerides (TG) are a hallmark of atherogenic dyslipidemia, representing a marker of atherogenic small dense low-density lipoproteins (sdlDL). Importantly, non-fasting/postprandial TG measurements tend to be emphasized in clinical practice for the prediction of CVD, and TG-lowering agents (primarily fibrates) have a beneficial effect on atherogenic dyslipidemia, reducing TG-rich particles and ultimately lowering the production of sdlDL. The combination of omega-3 fatty acids and statins is also recommended, and widely used in clinical practice for subjects with hypertriglyceridemia. However, a consensus on the optimal clinical use of these pharmacological agents is not fully established yet, and additional large clinical studies are needed. It seems that there is a favorable association between fish consumption and mortality from CVD, but it remains to be confirmed by future trials. Finally, there are a number of novel therapies, such as those targeting microsomal transport protein and its inhibitors, which represent new promising option for treating subjects with hypertriglyceridemia.

Non-glycemic effects of pioglitazone and incretin-based therapies

Atherosclerosis and cardiovascular events are highly prevalent and represent the major cause of mortality in patients with type 2 diabetes. Therefore, there is significant interest in the non-glycemic properties of anti-diabetic agents, particularly on those that are effective on cardiovascular risk factors. Thiazolidinediones and incretin-based therapies (IBTs) represent some of the most recent treatment options approved for the management of type 2 diabetes; these agents have shown important glycemic effects, as well as a number of non-glycemic effects. The latter include those on body weight, inflammation, hypertension and dyslipidemia, thus impacting the different components of the metabolic syndrome. Pioglitazone has been shown to significantly reduce cardiovascular adverse outcomes, while preliminary data on IBTs are very encouraging as well. Although highlighting the non-glycemic effects of pioglitazone and incretin-based therapies is of potential significance, clinical practice and patient care must be based largely on evidence-based medicine. Therefore, definitive opinions will await additional data from ongoing studies evaluating the effects of both GLP-1 agonists and DPP-4 inhibitors on cardiovascular morbidity and mortality.