Reduced Serum Vitamin D Levels Are Associated with Insulin Resistance in Patients with Obstructive Sleep Apnea Syndrome.

Background and objectives: Obstructive sleep apnea syndrome (OSAS) is associated with cardiovascular and metabolic risk factors, such as insulin resistance. Furthermore, OSAS has been associated with decreased levels of vitamin D (Vit D). The aim of the study was to assess the association between Vit D levels (expressed as 25(OH)D serum levels) and insulin resistance in patients with OSAS. Materials and Methods: Serum 25(OH)D levels were measured in consecutive subjects who had undergone polysomnography and pulmonary function testing. OSAS patients were divided into those with (homeostatic model assessment [HOMA-IR] ≥ 2) and without insulin resistance (HOMA-IR < 2). Results: Overall, 92 patients (81 males) were included in the study. OSAS patients with insulin resistance significantly differed from those without insulin resistance in terms of the body-mass index (BMI) (36.3 ± 5.8 compared to 32 ± 5.6 kg/m2, respectively, p = 0.001), apnoea-hypopnoea index (AHI) (57.4 ± 28.9 compared to 40.9 ± 27.9 events/h, respectively, p = 0.009) and indices of hypoxia during sleep. Patients with OSAS and insulin resistance had lower levels of serum 25 (OH) D compared with OSAS but without insulin resistance (19.3 ± 11.5 vs 26.7 ± 12.2 ng/mL, respectively, p = 0.005). Regression analysis demonstrated a negative association of 25(OH)D levels (ß = -0.048, odds ratio [OR]: 0.953, 95% confidence interval [CI]: 0.913-0.995, p = 0.030) and a positive association of BMI (ß = 0.110, OR: 1.116, 95% CI: 1.007-1.237, p = 0.036) with insulin resistance. Conclusions: Vit D insufficiency was significantly more frequent among OSAS patients with insulin resistance. Both low 25(OH)D levels and high BMI were associated with the risk of insulin resistance in this population.

Pleiotropic effects of proprotein convertase subtilisin/kexin type 9 inhibitors?

PURPOSE OF REVIEW: Current data suggest that proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors may affect many metabolic pathways beyond lowering LDL cholesterol. The aim of the present manuscript is to present these so-called pleiotropic effects of PCSK9 inhibitors. RECENT FINDINGS: PCSK9 may affect the activity of other receptors beyond LDL receptors (LDLR), such as cluster of differentiation 36 (CD36), very-low-density-lipoprotein (VLDL) receptors, apolipoprotein (Apo) E receptors, LDLR-related protein 1 (LRP-1) and ATP-Binding Cassette Transporter (ABCA1). Thus, a role of PCSK9 in the development of atherosclerosis, in vascular wall inflammation and in platelet function has been suggested. Additionally, PCSK9 inhibitors may affect lipid variables beyond LDL cholesterol, carbohydrate variables, as well as they may affect brain and kidney function. Additionally, a controversial role of PCSK9 in sepsis, hepatitis C infection and Alzheimer's disease has been suggested. SUMMARY: These possible pleiotropic effects of PCSK9 inhibitors need further research, as they may affect cardiovascular risk and provide further insights in the development of atherosclerosis and other diseases such as Alzheimer's disease or chronic viral infection and sepsis.

Treatment of Hypertension in Chronic Kidney Disease.

PURPOSE OF REVIEW: Chronic kidney disease (CKD) is recognized as a worldwide epidemic. Hypertension commonly coexists with CKD and its prevalence is progressively increasing as kidney function declines. RECENT FINDINGS: For patients with established CKD and/or diabetes with albuminuria, the updated hypertension guidelines have recommended a blood pressure (BP) goal < 130/80 mmHg. Blood pressure level above 130/80 mmHg in CKD patients requires lifestyle modifications and multiple antihypertensive medications. According to recent guidelines, angiotensin-converting enzyme (ACE) inhibitors should be the drugs of first choice. Angiotensin II receptor blockers (ARBs) should be used if the ACE inhibitor is not tolerated. Non-dihydropyridine CCBs consistently reduce albuminuria and slow the decline in kidney function. Dihydropyridine CCBs should not be used as monotherapy in proteinuric CKD patients but always in combination with a RAAS blocker. Diuretics are commonly used and represent the cornerstone in the management of CKD patients. All the other agents are used when treatment with the other primary agents have failed. In patients with CKD, an intensive BP goal < 130/80 mmHg has been recommended. We review current treatment options.

NMR-Based Lipid Profiling of High Density Lipoprotein Particles in Healthy Subjects with Low, Normal, and Elevated HDL-Cholesterol.

Recent studies suggest that the cholesterol content of HDL (high density lipoproteins) may provide limited information on their antiatherogenic properties and that the composition and particles' structure provide more information on their functionality. We used NMR-based (nuclear magnetic resonance-based) lipidomics to study the relationships of serum HDL-C (HDL-cholesterol) levels with the lipid composition of HDL particles in three groups of subjects selected on the basis of their HDL-C levels. Subjects with low and high HDL-C levels exhibited differences in HDL lipidome compared to those with normal HDL-C levels. In pattern recognition analysis, the discrimination power among all groups was of high significance. The low HDL-C group presented enrichment of the core in triglycerides and depletion in cholesterol esters, whereas the high HDL-C group showed a decrease in triglycerides content. Additionally, as HDL-C increases, all lipid classes are esterified with higher percentage of unsaturated than saturated fatty acids. In addition to the aforementioned differences, the surface layer is enriched in sphingomyelin and free cholesterol in the high HDL-C level group. NMR-based lipidomic analysis of HDL can be particularly useful since it provides insights into molecular features and helps in the characterization of the atheroprotective function of HDL lipoproteins and in the identification of novel biomarkers of cardiovascular risk.

Statins and mortality: the untold story.

Statins are first-line evidence-based drugs for the management of dyslipidaemias and to reduce the risk of cardiovascular events. However, statin clinical trials have shown marginally significant benefits on mortality, especially in the primary prevention setting. A major limitation of those trials is their relatively short follow-up. A reduced number of fatal events within a 5-year follow-up make mortality benefits unlikely to arise. This is particularly relevant for the primary prevention trials, where the risk of cardiovascular death is low. The short follow-up is a limitation for safety assessments too. However, extended major statin trials failed to detect any major safety concerns. Safety and efficacy assessments are even more complicated considering the differences of cardiovascular risk status in primary prevention individuals, and also given some potential ethnic and inter-individual genetic variations in response to statin treatment. Considerable evidence suggests a favourable risk-benefit balance for statin treatment. It can be assumed that statins reduce mortality in the long term by preventing cardiovascular events with complications that reduce lifespan. Unfortunately, this hypothesis cannot be proven as there is no current ethical basis on designing long-term placebo-controlled statin trials. Nevertheless, by effectively reducing disabilities related to cardiovascular events, statins have major benefits for public health. Therefore, clinicians should not withhold statin treatment awaiting proof of mortality benefits, as this may remain an 'untold story'.

Does Supplementation with Omega-3 PUFAs Add to the Prevention of Cardiovascular Disease?

PURPOSE OF REVIEW: Omega-3 fatty acids are increasingly used for the protection of cardiovascular disease. The main but not the sole mechanism of action is the reduction of triglyceride levels. In this review, we summarize the effect of omega-3 supplements on all-cause and cardiovascular mortality, myocardial infarction, and stroke from the relevant randomized controlled trials. RECENT FINDINGS: Twenty-one randomized controlled trials assessed omega-3 supplementation on mortality and cardiovascular-related outcomes. From these studies, as well as from the relevant meta-analyses, we found that omega-3 supplements do not exert a consistent benefit for cardiovascular protection. There is uncertainty of a clear profit from omega-3 supplementation in cardiovascular disease.

The current role of thiazolidinediones in diabetes management.

Among the epidemics of modern time, type 2 diabetes mellitus (T2DM) is one of the main contributors to overall morbidity as well as mortality. A number of different treatment options are available for the management of diabetes. Among them thiazolidinediones (TZDs) is an interesting drug class since it does not target the result of T2DM, i.e., hyperglycemia but rather some of the core mechanisms of the disease. Indeed, glitazones increase insulin sensitivity by activating the peroxisome proliferator-activated receptor γ, which plays an important role in regulating various metabolic parameters. Although TZDs have an established efficacy in T2DM treatment, their usage during the past years was questioned following the emergence of some alarming data regarding their safety and especially the cardiovascular safety of rosiglitazone. As a result, there is often some skepticism about the current role of TZDs in T2DM management. This mainly affects rosiglitazone even leading to its withdrawal from several markets in contrast to pioglitazone, which has shown a beneficial cardiovascular profile. A comprehensive assessment of the benefit-to-risk ratio of TZDs is required in order to better understand the place of these drugs in T2DM management.

NMR-based lipidomic analysis of blood lipoproteins differentiates the progression of coronary heart disease.

Abnormal lipid composition and metabolism of plasma lipoproteins play a crucial role in the pathogenesis of coronary heart disease (CHD). A (1)H NMR-based lipidomic approach was used to investigate the correlation of coronary artery stenosis with the atherogenic (non-HDL) and atheroprotective (HDL) lipid profiles in 99 patients with CHD of various stages of disease and compared with 60 patients with normal coronary arteries (NCA), all documented in coronary angiography. The pattern recognition models created from lipid profiles predicted the presence of CHD with a sensitivity of 87% and a specificity of 88% in the HDL model and with 90% and 89% in the non-HDL model, respectively. Patients with mild, moderate, and severe coronary artery stenosis were progressively differentiated from those with NCA in the non-HDL model with a statistically significant separation of severe stage from both mild and moderate. In the HDL model, the progressive differentiation of the disease stages was statistically significant only between patients with mild and severe coronary artery stenosis. The lipid constituents of lipoproteins that mainly characterized the initial stages and then the progression of the disease were the high levels of saturated fatty acids in lipids in both HDL and non-HDL particles, the low levels of HDL-phosphatidylcholine, HDL-sphingomyelin, and omega-3 fatty acids and linoleic acid in lipids in non-HDL particles. The conventional lipid marker, total cholesterol, found in low levels in HDL and in high levels in non-HDL, also contributed to the onset of the disease but with a much lower coefficient of significance. (1)H NMR-based lipidomic analysis of atherogenic and atheroprotective lipoproteins could contribute to the early evaluation of the onset of coronary artery disease and possibly to the establishment of an appropriate therapeutic option.

Emerging drugs for hyperlipidaemia: an update.

INTRODUCTION: Hypercholesterolaemia is a significant risk factor for cardiovascular disease (CVD), a major cause of morbidity and mortality. Up to now, the appropriate management has been aggressive hypolipidaemic therapy, particularly with statins, aiming at certain low-density lipoprotein cholesterol (LDL-C) levels for each patient population. This strategy has reduced CVD-related morbidity and mortality. However, many cardiovascular events still occur, probably as a consequence of lipid disorders other than high LDL-C concentration or other risk factors. Because statins do not eliminate the residual CVD risk, there seems to be place for novel lipid modifying drugs with different mechanisms of action. AREAS COVERED: This review is an update since 2010 regarding lipid-modifying drugs in development and their potent role in clinical practice. It focuses on cholesterol ester transfer protein inhibitors, mainly anacetrapib and evacetrapib, microsomal triglyceride transfer protein inhibitors, antisense oligonucleotides, pre-protein convertase subtilisin kexin-9 inhibitors and high-density lipoprotein mimetics. EXPERT OPINION: Several novel lipid-modifying drugs may be beneficial for certain patient populations. However, ongoing and future studies with clinical outcomes will clarify their actual role in clinical practice.

Fenofibrate and the kidney: an overview.

BACKGROUND: Fenofibrate has been used for the management of atherogenic dyslipidaemia for many years. Reports of fenofibrate-associated increases in serum creatinine (SCr) levels raised concerns regarding deleterious effects on renal function. DESIGN: In this narrative review, we discuss available literature on the effect of fenofibrate on the kidney. RESULTS: Most clinical studies showed a rapid (within weeks) raising effect of fenofibrate on SCr levels. This was often accompanied by declined estimated glomerular filtration rate. Risk predictors of this adverse effect might include increased age, impaired renal function and high-dose treatment. Also, the concomitant use of medications affecting renal hemodynamics (e.g. angiotensin-converting enzyme-inhibitors (ACEi) and angiotensin receptor blockers) may predispose to fenofibrate-associated increased SCr levels. Interestingly, SCr increases by fenofibrate were transient and reversible even without treatment discontinuation. Furthermore, fenofibrate was associated with a slower progression of renal function impairment and albuminuria in a long-term basis. Also, fenofibrate might be protective against pathological changes in diabetic nephropathy and hypertensive glomerulosclerosis. In this context, it is uncertain whether fenofibrate-associated increase in SCr levels mirrors true renal function deterioration. Several theories have been expressed. The most dominant one involved the inhibition of renal vasodilatory prostaglandins reducing renal plasma flow and glomerular pressure. Increased creatinine secretion or reduced creatinine clearance by fenofibrate was also suggested. These hypotheses should be settled by further studies. CONCLUSIONS: Fenofibrate may not be a nephrotoxic drug. However, a close monitoring of SCr levels is relevant especially in high-risk patients. Increases in SCr levels ≥30% can impose treatment discontinuation.