Effect of Ramipril and of Rosiglitazone on Carotid Intima-Media Thickness in People With Impaired Glucose Tolerance or Impaired Fasting Glucose

Angiotensin-converting enzyme inhibitor induced cough compared with placebo, and other antihypertensives: A systematic review, and network meta-analysis

Studies have shown that angiotensin converting enzyme inhibitors (ACEIs) are superior in primary and secondary prevention for cardiac mortality and morbidity to angiotensin receptor blocker (ARBs). One of the common side effects from ACEI is dry cough. The aims of this systematic review, and network meta-analysis are to rank the risk of cough induced by different ACEIs and between ACEI and placebo, ARB or calcium channel blockers (CCB). We performed a systematic review, and network meta-analysis of randomized controlled trials to rank the risk of cough induced by each ACEI and between ACEI and placebo, ARB or CCB. A total of 135 RCTs with 45,420 patients treated with eleven ACEIs were included in the analyses. The pooled estimated relative risk (RR) between ACEI and placebo was 2.21 (95% CI: 2.05-2.39). ACEI had more incidences of cough than ARB (RR 3.2; 95% CI: 2.91, 3.51), and pooled estimated of RR between ACEI and CCB was 5.30 (95% CI: 4.32-6.50) Moexipril ranked as number one for inducing cough (SUCRA 80.4%) and spirapril ranked the least (SUCRA 12.3%). The order for the rest of the ACEIs are as follows: ramipril (SUCRA 76.4%), fosinopril (SUCRA 72.5%), lisinopril (SUCRA 64.7%), benazepril (SUCRA 58.6%), quinapril (SUCRA 56.5%), perindopril (SUCRA 54.1%), enalapril (SUCRA 49.7%), trandolapril (SUCRA 44.6%) and, captopril (SUCRA 13.7%). All ACEI has the similar risk of developing a cough. ACEI should be avoided in patients who have risk of developing cough, and an ARB or CCB is an alternative based on the patient's comorbidity.

Traditional Risk Factors are Causally Related to Carotid Intima-Media Thickness Progression: Inferences from Observational Cohort Studies and Interventional Trials

In the present review, associations between traditional vascular risk factors (VRFs) and carotid intimamedial thickness progression (C-IMTp) as well as the effects of therapies for VRFs control on C-IMTp were appraised to infer causality between each VRF and C-IMTp. Cohort studies indicate that smoking, binge drinking, fatness, diabetes, hypertension and hypercholesterolemia are associated with accelerated C-IMTp. An exception is physical activity, with mixed data. Interventions for the control of obesity, diabetes, hypertension and hypercholesterolemia decelerate C-IMTp. Conversely, scarce information is available regarding the effect of smoking cessation, stop of excessive alcohol intake and management of the metabolic syndrome. Altogether, these data support a causative role of several traditional VRFs on C-IMTp. Shortcomings in study design and/or ultrasonographic protocols may account for most negative studies, which underlines the importance of careful consideration of methodological aspects in investigations using C-IMTp as the outcome.

Usefulness of Carotid Ultrasonography for Risk Stratification of Cerebral and Cardiovascular Disease

Carotid ultrasonography is useful for the assessments of the risk stratification for stroke or coronary artery disease, because it is a simple, repeatable, and noninvasive procedure. The carotid intima-media thickness (IMT), which is assessed using carotid ultrasonography, is a widely used surrogate marker for the severity of atherosclerosis. Several large clinical studies showed that increased carotid IMT is associated with the future stroke or cardiovascular events. In addition, in many clinical trials, it has been adopted for surrogate markers of clinical endpoints of medical intervention. Moreover, carotid ultrasonography allows the measurement of the presence and characteristics of plaques and the severity of carotid artery stenosis. The unstable morphology of plaque, such as hypoechoic, ulcer, and mobility, is associated with future ischemic stroke events. The screening tool of asymptomatic carotid artery stenosis is also important, although whether routine carotid ultrasonography assessment is recommended in the general population remains controversial. The screening of carotid artery stenosis using ultrasonography is essential for not only daily clinical settings but also management of patients with acute ischemic stroke. The patients with atherothrombotic stroke with severe internal carotid artery stenosis should be considered to surgical intervention, and duplex ultrasound approach is important to estimate for the severity of carotid stenosis. Physicians should keep in mind the usefulness of carotid ultrasonography for risk stratification of cerebral and cardiovascular disease based on various aspects. In addition, visual assessment or dynamic changes using carotid ultrasonography could provide the various and valuable insights in clinical settings.

PPARγ and RhoBTB1 in hypertension

PURPOSE OF REVIEW

This review provides an up-to-date understanding of how peroxisome proliferator activated receptor γ (PPARγ) exerts its cardioprotective effect in the vasculature through its activation of novel PPARγ target genes in endothelium and vascular smooth muscle.

RECENT FINDINGS

In vascular endothelial cells, PPARγ plays a protective role by increasing nitric oxide bioavailability and preventing oxidative stress. RBP7 is a PPARγ target gene enriched in vascular endothelial cells, which is likely to form a positive feedback loop with PPARγ. In vascular smooth muscle cells, PPARγ antagonizes the renin-angiotensin system, maintains vascular integrity, suppresses vasoconstriction, and promotes vasodilation through distinct pathways. Rho-related BTB domain containing protein 1 (RhoBTB1) is a novel PPARγ gene target in vascular smooth muscle cells that mediates the protective effect of PPARγ by serving as a substrate adaptor between the Cullin-3 RING ubiquitin ligase and phosphodiesterase 5, thus restraining its activity through ubiquitination and proteasomal degradation.

SUMMARY

In the vasculature, PPARγ exerts its cardioprotective effect through its transcriptional activity in endothelium and vascular smooth muscle. From the understanding of PPARγ's transcription targets in those pathways, novel hypertension therapy target(s) will emerge.

Carotid Intima-Media Thickness Progression as Surrogate Marker for Cardiovascular Risk: Meta-Analysis of 119 Clinical Trials Involving 100 667 Patients

BACKGROUND

To quantify the association between effects of interventions on carotid intima-media thickness (cIMT) progression and their effects on cardiovascular disease (CVD) risk.

METHODS

We systematically collated data from randomized, controlled trials. cIMT was assessed as the mean value at the common-carotid-artery; if unavailable, the maximum value at the common-carotid-artery or other cIMT measures were used. The primary outcome was a combined CVD end point defined as myocardial infarction, stroke, revascularization procedures, or fatal CVD. We estimated intervention effects on cIMT progression and incident CVD for each trial, before relating the 2 using a Bayesian meta-regression approach.

RESULTS

We analyzed data of 119 randomized, controlled trials involving 100 667 patients (mean age 62 years, 42% female). Over an average follow-up of 3.7 years, 12 038 patients developed the combined CVD end point. Across all interventions, each 10 μm/y reduction of cIMT progression resulted in a relative risk for CVD of 0.91 (95% Credible Interval, 0.87-0.94), with an additional relative risk for CVD of 0.92 (0.87-0.97) being achieved independent of cIMT progression. Taken together, we estimated that interventions reducing cIMT progression by 10, 20, 30, or 40 μm/y would yield relative risks of 0.84 (0.75-0.93), 0.76 (0.67-0.85), 0.69 (0.59-0.79), or 0.63 (0.52-0.74), respectively. Results were similar when grouping trials by type of intervention, time of conduct, time to ultrasound follow-up, availability of individual-participant data, primary versus secondary prevention trials, type of cIMT measurement, and proportion of female patients.

CONCLUSIONS

The extent of intervention effects on cIMT progression predicted the degree of CVD risk reduction. This provides a missing link supporting the usefulness of cIMT progression as a surrogate marker for CVD risk in clinical trials.

Sitagliptin on Carotid Intima-Media Thickness in Type 2 Diabetes Mellitus Patients and Anemia: A Subgroup Analysis of the PROLOGUE Study

Introduction

Randomized clinical trials have not shown an additional clinical benefit of sitagliptin treatment over conventional treatment alone. However, studies of sitagliptin treatment have not examined the relationship between anemia and treatment group outcomes.

Methods

The PROLOGUE study is a prospective clinical trial of 442 participants with type 2 diabetes mellitus (T2DM) randomized to sitagliptin treatment or conventional treatment which showed no treatment differences [Estimated mean (± standard error) common carotid intima-media thickness (CIMT) was 0.827 ± 0.007 mm and 0.837 ± 0.007 mm, respectively, with a mean difference of -0.009 mm (97.2% CI −0.028 to 0.011, p = 0.309) at 24 mo of follow-up]. This is a post hoc subanalysis using data obtained from the PROLOGUE study; the study population was divided into anemic groups (n = 94) and nonanemic group (n = 343) based on hemoglobin level. And we analyzed for the changes in each CIMT parameter from baseline to 24 months in subgroups.

Results

The treatment group difference in baseline-adjusted mean common carotid artery- (CCA-) IMT at 24 months was −0.003 mm (95% CI −0.022 to 0.015, p = 0.718) in the nonanemic subgroup and −0.007 mm (95% CI −0.043 to 0.030, p = 0.724) in the anemic subgroup. Although there were no significant differences in the other CIMT parameters between the treatment groups in the anemic subgroup, the changes in mean and max ICA-IMT at 24 months in the nonanemic subgroup were significantly lower in the sitagliptin group than the conventional group [−0.104 mm (95% CI −0.182 to −0.026), p = 0.009 and −0.142 mm (−0.252 to −0.033), p = 0.011, respectively].

Conclusion

These data suggest that nonanemia may indicate a potentially large subgroup of those with T2DM patients that sitagliptin therapy has a better antiatherosclerotic effect than conventional therapy. Further research is needed to confirm these preliminary observations.

Exploration and Development of PPAR Modulators in Health and Disease: An Update of Clinical Evidence

Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors that govern the expression of genes responsible for energy metabolism, cellular development, and differentiation. Their crucial biological roles dictate the significance of PPAR-targeting synthetic ligands in medical research and drug discovery. Clinical implications of PPAR agonists span across a wide range of health conditions, including metabolic diseases, chronic inflammatory diseases, infections, autoimmune diseases, neurological and psychiatric disorders, and malignancies. In this review we aim to consolidate existing clinical evidence of PPAR modulators, highlighting their clinical prospects and challenges. Findings from clinical trials revealed that different agonists of the same PPAR subtype could present different safety profiles and clinical outcomes in a disease-dependent manner. Pemafibrate, due to its high selectivity, is likely to replace other PPARα agonists for dyslipidemia and cardiovascular diseases. PPARγ agonist pioglitazone showed tremendous promises in many non-metabolic disorders like chronic kidney disease, depression, inflammation, and autoimmune diseases. The clinical niche of PPARβ/δ agonists is less well-explored. Interestingly, dual- or pan-PPAR agonists, namely chiglitazar, saroglitazar, elafibranor, and lanifibranor, are gaining momentum with their optimistic outcomes in many diseases including type 2 diabetes, dyslipidemia, non-alcoholic fatty liver disease, and primary biliary cholangitis. Notably, the preclinical and clinical development for PPAR antagonists remains unacceptably deficient. We anticipate the future design of better PPAR modulators with minimal off-target effects, high selectivity, superior bioavailability, and pharmacokinetics. This will open new possibilities for PPAR ligands in medicine.

Does diabetes prevention translate into reduced long-term vascular complications of diabetes?

The global epidemic of type 2 diabetes has prompted numerous studies and public health efforts to reduce its development. A variety of interventions, including lifestyle modifications and pharmacological agents directed at ameliorating the major risk factors for type 2 diabetes, are of proven efficacy in reducing the development of type 2 diabetes in people with impaired glucose tolerance. While prevention of the hyperglycaemia characteristic of diabetes is arguably an important, clinically relevant outcome, a more compelling outcome with greater clinical significance is the prevention or reduction of the relatively diabetes-specific microvascular and less-specific cardiovascular disease (CVD) complications associated with diabetes. These complications cause the majority of morbidity and excess mortality associated with diabetes. Any reduction in diabetes should, logically, also reduce the occurrence of its long-term complications; however, most diabetes prevention trials have not been of sufficient duration to allow such an evaluation. The limited long-term data, largely from the Da Qing Diabetes Prevention Study (DQDPS) and the Diabetes Prevention Program (DPP) and their respective follow-up studies (DQDPOS and DPPOS), suggest a reduction in microvascular complications and amelioration of CVD risk factors. Only the DQDPOS and Study to Prevent Non-Insulin-Dependent Diabetes Mellitus (STOP-NIDDM) studies have shown a reduction in CVD events and only DQDPOS has demonstrated a decrease in CVD and overall mortality. While these limited data are promising, whether diabetes prevention directly reduces complication-related morbidity and mortality remains unclear. Longer follow-up of prevention studies is needed to supplement the limited current clinical trial data, to help differentiate the effects of diabetes prevention itself from the means used to reduce diabetes development and to understand the balance among benefits, risks and costs of prevention.

Comparative effects of lipid lowering, hypoglycemic, antihypertensive and antiplatelet medications on carotid artery intima-media thickness progression: a network meta-analysis

Background

Carotid artery intima-media thickness (cIMT) progression is a surrogate marker of atherosclerosis with a high predictive value for future CVD risk. This study evaluates the comparative efficacies of lipid lowering, hypoglycemic, antihypertensive and antiplatelet medications on cIMT progression.

Methods

We conducted a network meta-analysis (NMA) to evaluate the relative efficacies of several drug classes in modifying cIMT progression. After a literature search in several electronic databases, studies were selected by following predetermined eligibility criteria. An inverse variance-heterogeneity model was used for NMA. Sensitivity analyses were performed to check the reliability of the overall NMA, and transitivity analyses were performed to examine the effects of modifiers on the NMA outcomes.

Results

Data were taken from 47 studies (15,721 patients; age: 60.2 years [95% confidence interval (CI) 58.8, 61.6]; BMI: 27.2 kg/m² [95% CI 26.4, 28.0]; and gender: 58.3% males [95% CI 48.3, 68.3]). Treatment duration was 25.8 months [95% CI 22.9, 28.7]. Of the 13 drug classes in the network, treatment with phosphodiesterase III inhibitors was the most effective in retarding annual mean cIMT against network placebo (weighted mean difference (WMD) − 0.059 mm [95% CI − 0.099, − 0.020) followed by the calcium channel blockers (WMD − 0.055 mm [95% CI − 0.099, 0.001]) and platelet adenosine diphosphate inhibitors (WMD − 0.033 mm [95% CI − 0.058, 0.008]). These 3 drug classes also attained the same positions when the NMA was conducted by using first-year changes in mean cIMT. In transitivity analyses, longer treatment duration, higher body mass index (BMI), and a higher baseline cIMT were found to be independently associated with a lesser reduction in annual mean cIMT. However, in a multivariate analysis with these 3 modifiers, none of these factors was significantly associated with annual change in mean cIMT. In the placebo group, age was inversely associated with annual change in mean cIMT independently.

Conclusion

Phosphodiesterase III inhibitors and calcium channel blockers are found more effective than other drug classes in retarding cIMT progression. Age, BMI, and baseline cIMT may have some impact on these outcomes.

Electronic supplementary material

The online version of this article (10.1186/s12933-019-0817-1) contains supplementary material, which is available to authorized users.

PPARγ and Its Role in Cardiovascular Diseases

Peroxisome proliferator-activated receptor Gamma (PPARγ), a ligand-activated transcription factor, has a role in various cellular functions as well as glucose homeostasis, lipid metabolism, and prevention of oxidative stress. The activators of PPARγ are already widely used in the treatment of diabetes mellitus. The cardioprotective effect of PPARγ activation has been studied extensively over the years making them potential therapeutic targets in diseases associated with cardiovascular disorders. However, they are also associated with adverse cardiovascular events such as congestive heart failure and myocardial infarction. This review aims to discuss the role of PPARγ in the various cardiovascular diseases and summarize the current knowledge on PPARγ agonists from multiple clinical trials. Finally, we also review the new PPARγ agonists under development as potential therapeutics with reduced or no adverse effects.

Carotid Intima-media Thickness Measurements: Relations with Atherosclerosis, Risk of Cardiovascular Disease and Application in Randomized Controlled Trials

Advances in the field of carotid ultrasound have been incremental, resulting in a steady decrease in measurement variability. Improvements in edge detection algorithms point toward increasing automation of CIMT measurements. The major advantage of CIMT is that it is completely noninvasive and can be repeated as often as required. It provides a continuous measure since all subjects have a measurable carotid wall. It is also relatively inexpensive to perform, and the technology is widely available. A graded relation between raising LDL cholesterol and increased CIMT is apparent. Increased CIMT has been shown consistently to relate the atherosclerotic abnormalities elsewhere in the arterial system. Moreover, increased CIMT predicts future vascular events in both populations from Caucasian ancestry and those from Asian ancestry. Furthermore, lipid‑lowering therapy has been shown to affect CIMT progression within 12–18 months in properly designed trials with results congruent with clinical events trials. In conclusion, when one wants to evaluate the effect of a pharmaceutical intervention that is to be expected to beneficially affect atherosclerosis progression and to reduce CV event risk, the use of CIMT measurements over time is a valid, suitable, and evidence‑based choice.

Circulating adiponectin and carotid intima-media thickness: A systematic review and meta-analysis

BACKGROUND

Adiponectin (APN) is an adipokine with insulin-sensitizing, anti-inflammatory, and vasculoprotective properties. Hypoadiponectinemia has been linked with disease states, such as obesity, type 2 diabetes, and cardiovascular disease. Carotid intima-media thickness (cIMT) is a strong and independent predictor of both coronary and cerebrovascular events, and has been used as a surrogate marker of subclinical atherosclerosis. The aim of this report is to systematically review the evidence on the relationship between APN and cIMT in a wide range of individuals.

MATERIALS AND METHODS

Medline, Embase, Biosis, Scopus, Web of Science, and Pubmed were searched for published studies and conference abstracts. The "sign test" and "vote count" methods were used to estimate the direction and significance of the relationship between APN and cIMT. The quality of the eligible studies was evaluated using an adapted version of the New Castle Ottawa quality assessment scale.

RESULTS

Fifty-five articles fulfilled the inclusion criteria, comprised of only cross-sectional studies, including healthy subjects, general population, and individuals with metabolic, inflammatory, or other chronic diseases. Most associations between APN and cIMT followed a negative direction in the healthier and general populations, and also in cohorts with metabolic disorders and other chronic diseases, but not in those with inflammatory diseases (sign test). These associations were generally found to be weak or non-significant among all cohort groups studied (vote count).

CONCLUSION

Our results are suggestive but not conclusive for an inverse association between APN levels and cIMT in diseased and non-diseased populations.

Carotid Intima-Media Thickness for Atherosclerosis

The carotid intima-media thickness (IMT) is a widely used surrogate marker for atherosclerosis worldwide. The carotid IMT can be simply, noninvasively, and reproducibly measured through B-mode carotid ultrasound. The carotid IMT is also a strong predictor of future cerebral and cardiovascular events. In addition, regressions of increased carotid IMT by lipid-lowering and antihypertensive drugs have been reported. Despite the strong association between increased carotid IMT and cardiovascular disease, it remains unclear whether routine carotid IMT measurement is useful for the detection of subclinical atherosclerosis in clinical practice. Researches should consider other methodological aspects, such as the definition of carotid plaques, the choice of measurement sites on the common or internal carotid artery, and the assessment of maximum or minimum IMT. The detailed guidelines for measuring carotid IMT vary by county. Thus, the usefulness of the carotid IMT may be assessed in different countries taking racial differences into account. Other important parameters revealed by carotid ultrasound, such as artery stenosis and the characteristics and size of plaques, should also be considered. Physicians should comprehensively interpret the results of carotid ultrasonography. Therefore, carotid ultrasonography is an essential tool for assessing cardiovascular risk in clinical settings.

Carotid intima-media thickness progression and risk of vascular events in people with diabetes: results from the PROG-IMT collaboration

OBJECTIVE

Carotid intima-media thickness (CIMT) is a marker of subclinical organ damage and predicts cardiovascular disease (CVD) events in the general population. It has also been associated with vascular risk in people with diabetes. However, the association of CIMT change in repeated examinations with subsequent CVD events is uncertain, and its use as a surrogate end point in clinical trials is controversial. We aimed at determining the relation of CIMT change to CVD events in people with diabetes.

RESEARCH DESIGN AND METHODS

In a comprehensive meta-analysis of individual participant data, we collated data from 3,902 adults (age 33-92 years) with type 2 diabetes from 21 population-based cohorts. We calculated the hazard ratio (HR) per standard deviation (SD) difference in mean common carotid artery intima-media thickness (CCA-IMT) or in CCA-IMT progression, both calculated from two examinations on average 3.6 years apart, for each cohort, and combined the estimates with random-effects meta-analysis.

RESULTS

Average mean CCA-IMT ranged from 0.72 to 0.97 mm across cohorts in people with diabetes. The HR of CVD events was 1.22 (95% CI 1.12-1.33) per SD difference in mean CCA-IMT, after adjustment for age, sex, and cardiometabolic risk factors. Average mean CCA-IMT progression in people with diabetes ranged between -0.09 and 0.04 mm/year. The HR per SD difference in mean CCA-IMT progression was 0.99 (0.91-1.08).

CONCLUSIONS

Despite reproducing the association between CIMT level and vascular risk in subjects with diabetes, we did not find an association between CIMT change and vascular risk. These results do not support the use of CIMT progression as a surrogate end point in clinical trials in people with diabetes.

Pharmacological interventions for preventing or delaying onset of type 2 diabetes mellitus

Prevention or delay of onset of type 2 diabetes in individuals at varying risk across the dysglycaemia continuum before overt diabetes becomes clinically manifest constitutes a leading objective of global disease prevention schemes. Pharmacological intervention has been suggested as a means to help prevent diabetes and reduce the global burden of this chronic condition. However, there is no credible evidence that early pharmacological intervention leads to long-term benefit in reducing diabetes-related complications or preventing early mortality, compared to treating people with diagnosed diabetes who have crossed the glycaemic threshold. In this review, we examine published evidence from trials using pharmacological agents to delay or prevent progression to diabetes. We also explore the benefit/risk impact of such therapies, safety issues and relevant off-target effects. Current evidence suggests none of the drugs currently available sustainably lower cumulative diabetes incidence, none provides a durable delay in diabetes diagnosis and none provides a convincing concomitant excess benefit for microvascular or macrovascular risk.

Prediabetes and associated disorders

Prediabetes represents an elevation of plasma glucose above the normal range but below that of clinical diabetes. Prediabetes includes individuals with IFG, IGT, IFG with IGT and elevated HbA1c levels. Insulin resistance and β-cell dysfunction are characteristic of this disorder. The diagnosis of prediabetesis is vital as both IFG and IGT are indeed well-known risk factors for type 2 diabetes with a greater risk in the presence of combined IFG and IGT. Furthermore, as will be illustrated in this review, prediabetes is associated with associated disorders typically only considered in with established diabetes. These include cardiovascular disease, periodontal disease, cognitive dysfunction, microvascular disease, blood pressure abnormalities, obstructive sleep apnea, low testosterone, metabolic syndrome, various biomarkers, fatty liver disease, and cancer. As the vast majority of individuals with prediabetes are unaware of their diagnosis, it is therefore vital that the associated conditions are identified, particularly in the presence of mild hyperglycemia, so they may benefit from early intervention.

Carotid intima-media thickness testing as an asymptomatic cardiovascular disease identifier and method for making therapeutic decisions

Cardiovascular disease (CVD) is the leading cause of death and disability in the United States. Although current therapies can reduce the risk for CVD, they are only given to patients who are considered to be at risk, and are therefore only beneficial if a patient's risk is accurately predicted before he or she sustains a cardiovascular (CV) event. Unfortunately, even relatively accurate risk factor analyses, such as the Reynolds Risk Score algorithm, fail to identify some patients who will sustain a CV event within 10 years. In contrast, the presence of an atheroma is an absolute predictor for the potential of an atherothrombotic event to occur, and it is therefore reasonable to anchor clinical decisions based on this knowledge. Carotid intima-media thickness (CIMT) testing via B-mode ultrasound is a safe, simple, and inexpensive method for evaluating CV risk by measuring the combined thickness of the intimal and medial layers of the arterial wall. Use of CIMT testing can also detect marked thickening of the arterial wall, possibly indicating plaques or atheromas that are associated with accelerated atherosclerotic disease and increased risk for coronary artery disease, myocardial infarction, and stroke. These characteristics make CIMT a practical supplemental method that physicians can use when making decisions. Moreover, the ability of CIMT testing to identify and quantify atherosclerotic disease has led to the adoption of CIMT as a surrogate endpoint in clinical trials, allowing the efficacy of new drugs to be assessed much more rapidly than would be possible by focusing solely on CV event or mortality rates. To date, several trials have provided evidence to indicate that some CVD therapies slow, stop, or reverse the progression of CIMT. Although many of these studies show that changes in CIMT predict future CV events, the value of CIMT testing in CVD risk assessment is still vigorously debated. In this article, we clarify the utility of CIMT testing for risk classification and reexamine its usefulness as a method for assessing therapeutic efficacy.

Effect of insulin glargine and n-3FA on carotid intima-media thickness in people with dysglycemia at high risk for cardiovascular events: the glucose reduction and atherosclerosis continuing evaluation study (ORIGIN-GRACE)

OBJECTIVE

To evaluate the effects of insulin glargine and n-3 polyunsaturated fatty acid (n-3FA) supplements on carotid intima-media thickness (CIMT).

RESEARCH DESIGN AND METHODS

We enrolled 1,184 people with cardiovascular (CV) disease and/or CV risk factors plus impaired fasting glucose, impaired glucose tolerance, or early type 2 diabetes in a randomized multicenter 2 × 2 factorial design trial. Participants received open-label insulin glargine (targeting fasting glucose levels ≤ 5.3 mmol/L [95 mg/dL]) or standard glycemic care and double-blind therapy with a 1-g capsule of n-3FA or placebo. The primary trial outcome was the annualized rate of change in maximum CIMT for the common carotid, bifurcation, and internal carotid artery segments. Secondary outcomes were the annualized rates of change in maximum CIMT for the common carotid and the common carotid plus bifurcation, respectively. Baseline followed by annual ultrasounds were obtained during a median follow-up of 4.9 years.

RESULTS

Compared with standard care, insulin glargine reduced the primary CIMT outcome, but the difference was not statistically significant (difference = 0.0030 ± 0.0021 mm/year; P = 0.145) and significantly reduced the secondary CIMT outcomes (differences of 0.0033 ± 0.0017 mm/year [P = 0.049] and 0.0045 ± 0.0021 mm/year [P = 0.032], respectively). There were no differences in the primary and secondary outcomes between the n-3FA supplement and placebo groups.

CONCLUSIONS

In people with CV disease and/or CV risk factors and dysglycemia, insulin glargine used to target normoglycemia modestly reduced CIMT progression, whereas daily supplementation with n-3FA had no effect on CIMT progression.

Loss of neuronatin promotes "browning" of primary mouse adipocytes while reducing Glut1-mediated glucose disposal

Failure of white adipose tissue to appropriately store excess metabolic substrate seems to underpin obesity-associated type 2 diabetes. Encouraging "browning" of white adipose has been suggested as a therapeutic strategy to help dispose of excess stored lipid and ameliorate the resulting insulin resistance. Genetic variation at the DNA locus encoding the novel proteolipid neuronatin has been associated with obesity, and we recently observed that neuronatin expression is reduced in subcutaneous adipose tissue from obese humans. Thus, to explore the function of neuronatin further, we used RNAi to silence its expression in murine primary adipocyte cultures and examined the effects on adipocyte phenotype. We found that primary adipocytes express only the longer isoform of neuronatin. Loss of neuronatin led to increased mitochondrial biogenesis, indicated by greater intensity of MitoTracker Green staining. This was accompanied by increased expression of UCP1 and the key genes in mitochondrial oxidative phosphorylation, PGC-1α, Cox8b, and Cox4 in primary subcutaneous white adipocytes, indicative of a "browning" effect. In addition, phosphorylation of AMPK and ACC was increased, suggestive of increased fatty acid utilization. Similar, but less pronounced, effects of neuronatin silencing were also noted in primary brown adipocytes. In contrast, loss of neuronatin caused a reduction in both basal and insulin-stimulated glucose uptake and glycogen synthesis, likely mediated by a reduction in Glut1 protein upon silencing of neuronatin. In contrast, loss of neuronatin had no effect on insulin signaling. In conclusion, neuronatin appears to be a novel regulator of browning and metabolic substrate disposal in white adipocytes.

Pioglitazone slows progression of atherosclerosis in prediabetes independent of changes in cardiovascular risk factors

OBJECTIVE

To determine whether changes in standard and novel risk factors during the Actos Now for Prevention of Diabetes trial explained the slower rate of carotid intima media thickness (CIMT) progression with pioglitazone treatment in persons with prediabetes.

METHODS AND RESULTS

CIMT was measured in 382 participants at the beginning and up to 3 additional times during follow-up of the Actos Now for Prevention of Diabetes trial. During an average follow-up of 2.3 years, the mean unadjusted annual rate of CIMT progression was significantly (P=0.01) lower with pioglitazone treatment (4.76×10(-3) mm/year; 95% CI: 2.39×10(-3)-7.14×10(-3) mm/year) compared with placebo (9.69×10(-3) mm/year; 95% CI: 7.24×10(-3)-12.15×10(-3) mm/year). High-density lipoprotein cholesterol, fasting and 2-hour glucose, HbA(1c), fasting insulin, Matsuda insulin sensitivity index, adiponectin, and plasminogen activator inhibitor-1 levels improved significantly with pioglitazone treatment compared with placebo (P<0.001). However, the effect of pioglitazone on CIMT progression was not attenuated by multiple methods of adjustment for traditional, metabolic, and inflammatory risk factors and concomitant medications, and was independent of changes in risk factors during pioglitazone treatment.

CONCLUSIONS

Pioglitazone slowed progression of CIMT, independent of improvement in hyperglycemia, insulin resistance, dyslipidemia, and systemic inflammation in prediabetes. These results suggest a possible direct vascular benefit of pioglitazone.

PPAR-γ as a therapeutic target in cardiovascular disease: evidence and uncertainty

Peroxisome proliferator-activated receptor γ (PPAR-γ) is a key regulator of fatty acid metabolism, promoting its storage in adipose tissue and reducing circulating concentrations of free fatty acids. Activation of PPAR-γ has favorable effects on measures of adipocyte function, insulin sensitivity, lipoprotein metabolism, and vascular structure and function. Despite these effects, clinical trials of thiazolidinedione PPAR-γ activators have not provided conclusive evidence that they reduce cardiovascular morbidity and mortality. The apparent disparity between effects on laboratory measurements and clinical outcomes may be related to limitations of clinical trials, adverse effects of PPAR-γ activation, or off-target effects of thiazolidinedione agents. This review addresses these issues from a clinician's perspective and highlights several ongoing clinical trials that may help to clarify the therapeutic role of PPAR-γ activators in cardiovascular disease.

Peroxisome proliferator-activated receptor (PPAR α/γ) agonists as a potential target to reduce cardiovascular risk in diabetes

The disappointing results of glucose lowering studies have highlighted the ongoing need to develop new therapeutic strategies to reduce cardiovascular risk in patients with type 2 diabetes. The presence of a range of metabolic abnormalities in diabetic patients presents a number of potential targets for therapeutic intervention. While modulation of peroxisome proliferator activated receptors (PPARs) represents an attractive approach, the results of studies of pharmacological agonists have been variable. The findings of these studies and rationale for development of dual PPAR-α/γ agonists will be reviewed.

Pre-diabetes, metabolic syndrome, and cardiovascular risk

Pre-diabetes represents an elevation of plasma glucose above the normal range but below that of clinical diabetes. Pre-diabetes can be identified as either impaired fasting glucose (IFG) or impaired glucose tolerance (IGT). The latter is detected by oral glucose tolerance testing. Both IFG and IGT are risk factors for type 2 diabetes, and risk is even greater when IFG and IGT occur together. Pre-diabetes commonly associates with the metabolic syndrome. Both in turn are closely associated with obesity. The mechanisms whereby obesity predisposes to pre-diabetes and metabolic syndrome are incompletely understood but likely have a common metabolic soil. Insulin resistance is a common factor; systemic inflammation engendered by obesity may be another. Pre-diabetes has only a minor impact on microvascular disease; glucose-lowering drugs can delay conversion to diabetes, but whether in the long run the drug approach will delay development of microvascular disease is in dispute. To date, the drug approach to prevention of microvascular disease starting with pre-diabetes has not been evaluated. Pre-diabetes carries some predictive power for macrovascular disease, but most of this association appears to be mediated through the metabolic syndrome. The preferred clinical approach to cardiovascular prevention is to treat all the metabolic risk factors. For both pre-diabetes and metabolic syndrome, the desirable approach is lifestyle intervention, especially weight reduction and physical activity. When drug therapy is contemplated and when the metabolic syndrome is present, the primary consideration is prevention of cardiovascular disease. The major targets are elevations of cholesterol and blood pressure.

Peroxisome proliferator-activated receptor-γ and the endothelium: implications in cardiovascular disease

Peroxisome proliferator-activated receptors-γ (PPARγs) are ligand-activated transcription factors that play a crucial regulatory role in the transcription of a large number of genes involved in lipid metabolism and inflammation. In addition to physiological ligands, synthetic ligands (the thiazoledinediones) have been developed. In spite of the much publicized adverse cardiovascular effects of one such thiazoledinedione (rosiglitazone), PPARγ activation may have beneficial cardiovascular effects. In this article we review the effects of PPARγ activation on the endothelium with special emphasis on the possible implications in cardiovascular disease. We discuss its possible role in inflammation, vasomotor function, thrombosis, angiogenesis, vascular aging and vascular rhythm. We also briefly review the clinical implications of these lines of research.

The cardiovascular effects of peroxisome proliferator-activated receptor agonists

Although peroxisome proliferator-activated receptor agonists are prescribed to improve cardiovascular risk factors, their cardiovascular safety is controversial. We therefore reviewed the literature to identify landmark randomized controlled trials evaluating the effect of peroxisome proliferator-activated receptor gamma agonists (pioglitazone and rosiglitazone), alpha agonists (fenofibrate and gemfibrozil), and pan agonists (bezafibrate, muraglitazar, ragaglitazar, tesaglitazar, and aleglitazar) on cardiovascular outcomes. Pioglitazone may modestly reduce cardiovascular events but also may increase the risk of bladder cancer. Rosiglitazone increases the risk of myocardial infarction and has been withdrawn in European and restricted in the United States. Fibrates improve cardiovascular outcomes only in select subgroups: fenofibrate in diabetic patients with metabolic syndrome, gemfibrozil in patients with dyslipidemia, and bezafibrate in patients with diabetes or metabolic syndrome. The cardiovascular safety of the new pan agonist aleglitazar, currently in phase II trials, remains to be determined. The heterogenous effects of peroxisome proliferator-activated receptor agonists to date highlight the importance of postmarketing surveillance. The critical question of why peroxisome proliferator-activated receptor agonists seem to improve cardiovascular risk factors without significantly improving cardiovascular outcomes requires further investigation.

Design, history and results of the Thiazolidinedione Intervention with vitamin D Evaluation (TIDE) randomised controlled trial

AIMS/OBJECTIVE

Conflicting data regarding cardiovascular effects of thiazolidinediones (TZDs) and extra-skeletal effects of vitamin D supported the need for a definitive trial. The Thiazolidinedione Intervention with vitamin D Evaluation (TIDE) trial aimed to assess the effects of TZDs (rosiglitazone and pioglitazone) on cardiovascular outcomes and the effects of vitamin D (cholecalciferol) on cancers and mortality.

METHODS

A large multicentre 3 × 2 factorial double-blind placebo-controlled randomised trial recruited from outpatient primary care and specialty clinics in 33 countries. From June 2009 to July 2010, 1,332 people with type 2 diabetes and other cardiovascular risk factors aged ≥ 50 years whose HbA(1c) was 6.5-9.5% (48-80 mmol/mol) when using two or fewer glucose-lowering drugs were randomised by a central computer system to placebo (n = 541), rosiglitazone 4-8 mg/day (n = 399) or pioglitazone 30-45 mg/day (n = 392); 1,221 participants were randomised to placebo (n = 614) or vitamin D 1,000 IU/day (n = 607). Participants and all study personnel were blind to treatment allocation. The primary outcome for the TZD arm was the composite of myocardial infarction, stroke or cardiovascular death, and for the vitamin D arm it was cancer or all-cause death. All randomised participants were included in the primary analysis.

RESULTS

From the study design, 16,000 people were to be followed for approximately 5.5 years. However, the trial was stopped prematurely because of regulatory concerns after a mean of 162 days without consideration of the accrued data. In the TZD arm, the cardiovascular outcome occurred in five participants (0.9%) in the placebo groups and three participants (0.4%) in the TZD groups (two allocated to pioglitazone, one to rosiglitazone). In the vitamin D arm, the primary outcome occurred in three participants (0.5%) in the placebo group and in two participants (0.3%) receiving vitamin D. Adverse events were comparable in all groups.

CONCLUSIONS/INTERPRETATION

Uncertainty persists regarding the clinically relevant risks and benefits of TZDs and vitamin D because of the early cancellation of this comprehensive trial.

Prediabetes: to treat or not to treat?

The incidence of diabetes is continuously increasing worldwide. Pre-diabetes (defined as impaired glucose tolerance, impaired fasting glucose or both) represents an intermediate state, which often progresses to overt diabetes within a few years. In addition, pre-diabetes may be associated with increased risk of microvascular and macrovascular complications. Thus, reverting a pre-diabetic state as well as preventing the development of diabetes represents enormous challenge for the clinician. Lifestyle modification in pre-diabetic individuals was found particularly effective in the prevention of diabetes. However, compliance to lifestyle modification measures can be a crucial problem in the everyday clinical practice, especially in developing countries. During the last decade many studies support the use of anti-diabetic treatment schemes in pre-diabetic subjects to be advantageous. The American Diabetes Prevention Program (DPP) as well as other minor studies and meta-analyses has convincingly demonstrated the efficacy of metformin in this patient group. In addition, results of the 10 year DPP follow up have recently been published, demonstrating the long term safety and sustainability of metformin treatment benefits in this population. In contrast to metformin, the evidence from the use of other anti-diabetic agents (thiazolidinediones, a-glucosidase inhibitors, incretin mimetics) in pre-diabetic individuals is rather inadequate and prospective data is further needed. Furthermore, large scale studies with hard clinical endpoints are needed to delineate the effect of pre-diabetes treatment on macro- and microvascular complications. In conclusion, several strategies of patient management, mainly lifestyle modification and pharmacological interventions can prevent diabetes development in subjects diagnosed with pre-diabetes or even revert pre-diabetic state. However, whether this biochemical improvement can be translated into actual clinical benefit remains to be established.

Measuring and targeting aldosterone and renin in atherosclerosis-a review of clinical data

Our understanding of the development and progression of atherosclerosis has increased substantially over the past decades. A significant role for the renin-angiotensin-aldosterone system (RAAS) in this process has gained appreciation in recent years. Preclinical and clinical studies have associated components of the RAAS with various cardiovascular disease conditions. Classically known for its contribution to hypertension, dysregulation of the system is now also believed to promote vascular inflammation, fibrosis, remodeling, and endothelial dysfunction, all intimately related to atherosclerosis. The reduction in cardiovascular mortality and morbidity, as seen with the use of angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers, supports the concept that RAAS is involved in the pathogenesis of atherosclerotic disease. However, the underlying molecular mechanisms of the pathophysiology remain to be completely understood. Evidence points toward additional benefit from therapeutic approaches aiming at more complete inhibition of the system and the possible utility of renin or aldosterone in the prediction of cardiovascular outcome. This review will summarize the current knowledge from clinical studies regarding the presumptive role of renin and aldosterone in the prediction and management of patients with atherosclerosis. For this purpose, a literature search was performed, focusing on available clinical data regarding renin or aldosterone and cardiovascular outcome.

Carotid intima-media thickness and cardiovascular risk

Cardiovascular disease is the primary cause of death in most developed nations. Identifying an individual's cardiovascular risk remains a challenge. Traditional coronary-risk stratification is based on cardiovascular risk factors using risk score systems, which may not reliably identify atherosclerosis in asymptomatic individuals. Carotid intima-media thickness measured by ultrasonography is a noninvasive, well-validated tool that has been used as a surrogate for clinical coronary events. Carotid intima-media thickness has demonstrable utility as an independent predictor of future cardiovascular events. Recent data have improved our understanding of its applications as a screening tool for cardiovascular disease.

Subclinical atherosclerosis: evolving role of carotid intima-media thickness

Cardiovascular risk factors have utility in risk prediction but have limitations in predicting individual risk. Identifying an individual's risk remains a challenge. Emerging technologies such as carotid artery ultrasonography and measures of carotid intima-media thickness (CIMT) may be useful in identifying the susceptible patient who may benefit from more aggressive preventive therapy. This screening test is noninvasive, reproducible, inexpensive, and radiation-free. Recent data have improved our understanding of the application of CIMT as a screening tool for cardiovascular disease. CIMT measurement may place an individual into a higher- or lower-risk category, allowing for appropriate institution of preventive strategies.

Addressing the burden of type 2 diabetes and cardiovascular disease through the management of postprandial hyperglycaemia: an Asian-Pacific perspective and expert recommendations

The world is facing an epidemic of cardiovascular disease (CVD) and type 2 diabetes, with populations in low- to middle-income countries, including many in the Asia Pacific (AP) region, being disproportionately affected. Emerging data identify postprandial hyperglycaemia (PPHG) as an important predictor of CVD, and several professional bodies, including the International Diabetes Federation, have issued guidelines on the management of PPHG in type 2 diabetes. Guidance on how international recommendations could be implemented in Asian populations is currently lacking. Therefore, a panel of experts from the AP region convened to consider the current status of PPHG and CVD in the region, and to develop recommendations for clinical practice. The group concluded that improved awareness of the impact of PPHG on CVD risk, among clinicians and the general public, and more widespread use of routine screening for PPHG, using oral glucose tolerance testing in those without recognised diabetes, are required. Additionally, frequent meal-based testing and effective PPHG management are essential to the management of IGT and type 2 diabetes.

Strategies for optimizing glycemic control and cardiovascular prognosis in patients with type 2 diabetes mellitus

Type 2 diabetes mellitus (DM) is a major cardiovascular (CV) risk factor and, as such, is considered a coronary artery disease risk equivalent. Although glycemic control is associated with decreased CV events epidemiologically, many prospective clinical trials have failed to conclusively demonstrate that aggressive glycemic control improves the CV prognosis of patients with type 2 DM, especially those with long-standing DM. Many therapies for type 2 DM with widely divergent mechanisms of action are available. Some of these drugs, in addition to their glucose-lowering actions, have properties that may reduce or increase CV events. Agents that lower both insulin resistance and postprandial hyperglycemia while at the same time avoiding hypoglycemia may be beneficial for CV health. This article reviews the evidence regarding the use of these agents and appropriate glycemic control targets for improving the adverse CV prognosis associated with type 2 DM. We conducted a systematic review of English articles using MEDLINE and the Cochrane Controlled Trials Register (1970-2010) using the following search terms: cardiovascular disease, randomized trials, hypoglycemia, and insulin resistance.

Carotid intima-media thickness as a surrogate marker of cardiovascular disease in diabetes

BACKGROUND

Diabetes mellitus is associated with a high risk of cardiovascular disease. Carotid intima-media thickness (CIMT) is increasingly used as a surrogate marker for atherosclerosis. Its use relies on its ability to predict future clinical cardiovascular end points.

METHODS

This review examines the evidence linking CIMT as a surrogate marker of vascular complications in people with type 1 and type 2 diabetes. We have also reviewed the various treatment strategies which have been shown to influence CIMT.

CONCLUSIONS

CIMT measurement is an effective, noninvasive tool which can assist in identifying people with diabetes who are at higher risk of developing microvascular and macrovascular complications. It may also help to evaluate the effectiveness of various treatment strategies used to treat people with diabetes.

Thiazolidinediones up-regulate insulin-like growth factor-1 receptor via a peroxisome proliferator-activated receptor gamma-independent pathway

There is increasing evidence that thiazolidinediones (TZDs), antidiabetic compounds that are synthetic ligands for the peroxisome proliferator-activated receptor γ (PPARγ), have cardiovascular effects through as yet poorly defined mechanisms. We tested the effect of two TZD class drugs, rosiglitazone and pioglitazone, on human aortic smooth muscle cell (SMC) expression of insulin-like growth factor-1 receptor (IGF-1R). Both TZDs dose dependently up-regulated IGF-1R protein levels (rosiglitazone, 10 μmol/liter, 67% increase, n = 4, p < 0.01; pioglitazone, 10 μmol/liter, 41% increase, n = 4, p < 0.01) and increased IGF-1R signaling activity (36% increase in Akt phosphorylation). However, the endogenous PPARγ ligand, 15-deoxy-Δ(12,14)-prostaglandin J(2), dose dependently reduced IGF-1R (10 μmol/liter, 80% decrease, n = 4, p < 0.01), and overexpression of PPARγ using an adenovirus likewise reduced IGF-1R (50% decrease versus SMC infected with control adenovirus), suggesting a PPARγ-independent action of TZDs. All three PPARγ ligands (rosiglitazone, pioglitazone, and 15-deoxy-Δ(12,14)-prostaglandin J(2)), however, did not change IGF-1R mRNA levels, indicating that their effects were posttranscriptional. Use of bicistronic constructs revealed that TZD induction of IGF-1R translation occurred via internal ribosomal entry. To examine the potential physiological relevance of TZD up-regulation of IGF-1R, we determined the effect of rosiglitazone on oxidized LDL (oxLDL)-induced apoptosis. 20 μmol/liter of rosiglitazone reduced oxidized LDL-induced apoptosis by 40% and neutralizing antibody to IGF-1R (αIR3) counteracted this rescue, suggesting the rosiglitazone survival effect was, at least in part, mediated by IGF-1R. In conclusion, TZDs markedly up-regulate SMC IGF-1R expression and signaling, likely via a PPARγ-independent mechanism. This novel action of TZDs may play an important role in their cardiovascular effects.

Are changes in carotid intima-media thickness related to risk of nonfatal myocardial infarction? A critical review and meta-regression analysis

BACKGROUND

Carotid intima-media thickness (CIMT) is increasingly being used as a surrogate end point in randomized control trials (RCTs) of novel cardiovascular therapies. However, it remains unclear whether changes in CIMT that result from these therapies correlate with nonfatal myocardial infarction (MI).

METHODS

We performed a literature search of RCTs from 1990-2009 that used CIMT. Eligible RCTs (1) included quantitative and sequential assessments in CIMT at least 1 year apart and (2) reported nonfatal MI. Across RCTs, random-effects metaregression was employed to correlate differences in mean change in CIMT between treatment and control groups over time with the log odds ratios of developing nonfatal MI during follow-up.

RESULTS

Overall, we identified 28 RCTs with 15,598 patients. Differences in mean change in CIMT over time between treatment and control groups correlated with developing nonfatal MI during follow-up: for each 0.01 mm per year smaller rate of change in CIMT, the odds ratio for MI was 0.82 (95% CI, 0.69 to 0.96; P = .018). Results were similar in subgroups of RCTs with >1 year follow-up (P = .018) and those with at least 50 subjects in the treatment group (P = .019). However, there was no significant relationship between mean change in CIMT and nonfatal MI in RCTs evaluating statin therapy or those with high CIMTs at baseline (P > .20 in both instances).

CONCLUSIONS

Less progression in CIMT over time is associated with a lower likelihood of nonfatal MI in selected RCTs; however, these findings were inconsistent at times, suggesting caution in using CIMT as a surrogate end point.

Strategies for the development of new PPAR agonists in diabetes

Diabetes is associated with a range of metabolic abnormalities including insulin resistance, atherogenic dyslipidemia, hypertension, and inflammation. These factors are likely to underlie the adverse cardiovascular outcome typically observed in diabetic cohorts. The family of peroxisome proliferator-activated receptors (PPARs) have been implicated in the regulation of a number of physiologic and metabolic pathways. Pharmacologic agonists directed against various PPARs have been shown to have a beneficial impact on these metabolic risk factors. The potential impact on cardiovascular risk with the use of PPAR agonists will be reviewed.

Carotid intima-media thickness: knowledge and application to everyday practice

Heart disease is the primary cause of death in the United States. Fortunately, intervention measures can reduce the risk of cardiovascular disease (CVD) after a patient has been accurately assessed. Atherosclerotic disease, one of the driving forces behind CVD, is not always detected by traditional risk assessment. Carotid intima-media thickness (CIMT), as measured by B-mode ultrasound, is a surrogate marker for atherosclerosis and can be used to detect an accelerated disease process and subclinical disease. Advantages of CIMT are that it is noninvasive, relatively inexpensive, and can be repeatedly performed with no adverse effects on the patient. Carotid intima-media thickness is associated with CVD and is an independent predictor of stroke and myocardial infarction. Therefore, CIMT is valuable for clarifying CVD risk, particularly for patients with intermediate risk by conventional risk assessment. Screening for subclinical disease even in low-risk patients may have benefit, especially for those with a family history of premature CVD or those with any of the National Cholesterol Education Program risk factors. The detection of subclinical atherosclerosis allows the physician to implement prevention efforts prior to a devastating CVD event and to investigate possible reasons for increased arterial thickening, such as an occult underlying insulin-resistant condition or residual lipid risk markers. Treatment with several types of drugs has been demonstrated to halt the progression or even reduce CIMT. Carotid intima-media thickness is currently limited by the lack of standardized protocols that may affect reproducibility from measure to measure. Efforts to draft a standardized protocol are underway by the Society of Atherosclerosis Imaging and Prevention that will address this issue. Carotid intima-media thickness provides a valuable tool for physicians to clarify the CVD risk of their patients. Practical implications of CIMT for everyday clinical practice are addressed.

Countervailing vascular effects of rosiglitazone in high cardiovascular risk mice: role of oxidative stress and PRMT-1

In the present study, we tested the hypothesis that the PPARγ (peroxisome-proliferator-activated receptor γ) activator rosiglitazone improves vascular structure and function in aged hyperhomocysteinaemic MTHFR (methylene tetrahydrofolate reductase) gene heterozygous knockout (mthfr+/−) mice fed a HCD (high-cholesterol diet), a model of high cardiovascular risk. One-year-old mthfr+/− mice were fed or not HCD (6 mg·kg−1 of body weight·day−1) and treated or not with rosiglitazone (20 mg·kg−1 of body weight·day−1) for 90 days and compared with wild-type mice. Endothelium-dependent relaxation of carotid arteries was significantly impaired (−40%) only in rosiglitazone-treated HCD-fed mthfr+/− mice. Carotid M/L (media-to-lumen ratio) and CSA (cross-sectional area) were increased (2-fold) in mthfr+/− mice fed or not HCD compared with wild-type mice (P<0.05). Rosiglitazone reduced M/L and CSA only in mthfr+/− mice fed a normal diet. Superoxide production was increased in mthfr+/− mice fed HCD treated or not with rosiglitazone, whereas plasma nitrite was decreased by rosiglitazone in mice fed or not HCD. PRMT-1 (protein arginine methyltransferase-1), involved in synthesis of the NO (nitric oxide) synthase inhibitor ADMA (asymmetric ω-NG,NG-dimethylarginine), and ADMA were increased only in rosiglitazone-treated HCD-fed mthfr+/− mice. Rosiglitazone had both beneficial and deleterious vascular effects in this animal model of high cardiovascular risk: it prevented carotid remodelling, but impaired endothelial function in part through enhanced oxidative stress and increased ADMA production in mice at high cardiovascular risk.

Does peroxisome proliferator-activated receptor-gamma (PPAR gamma) protect from hypertension directly through effects in the vasculature?

Peroxisome proliferator-activated receptor-gamma (PPAR gamma) is a ligand-activated transcription factor of the nuclear hormone receptor superfamily. Increasing evidence suggests that PPAR gamma is involved in the regulation of vascular function and blood pressure in addition to its well recognized role in metabolism. Thiazolidinediones, PPAR gamma agonists, lower blood pressure and have protective vascular effects through largely unknown mechanisms. In contrast, loss-of-function dominant-negative mutations in human PPAR gamma cause insulin resistance and severe early onset hypertension. Recent studies using genetically manipulated mouse models have begun to specifically address the importance of PPAR gamma in the vasculature. In this minireview, evidence for a protective role of PPAR gamma in the endothelium and vascular smooth muscle, derived largely from studies of genetically manipulated mice, will be discussed.