Lack of effects of pioglitazone on cardiac function in patients with type 2 diabetes and evidence of left ventricular diastolic dysfunction: a tissue doppler imaging study

Hypoglycemic Drugs in Patients with Diabetes Mellitus and Heart Failure: A Narrative Review

Over the last few years, given the increase in the incidence and prevalence of both type 2 diabetes mellitus (T2DM) and heart failure (HF), it became crucial to develop guidelines for the optimal preventive and treatment strategies for individuals facing these coexisting conditions. In patients aged over 65, HF hospitalization stands out as the predominant reason for hospital admissions, with their prognosis being associated with the presence or absence of T2DM. Historically, certain classes of glucose-lowering drugs, such as thiazolidinediones (rosiglitazone), raised concerns due to an observed increased risk of myocardial infarction (MI) and cardiovascular (CV)-related mortality. In response to these concerns, regulatory agencies started requiring CV outcome trials for all novel antidiabetic agents [i.e., dipeptidyl peptidase-4 inhibitors (DPP-4 inhibitors), glucagon-like peptide-1 receptor agonists (GLP-1 RAs), and sodium-glucose cotransporter-2 inhibitors (SGLT2is)] with the aim to assess the CV safety of these drugs beyond glycemic control. This narrative review aims to address the current knowledge about the impact of glucose-lowering agents used in T2DM on HF prevention, prognosis, and outcome.

Reducing Cardiac Steatosis: Interventions to Improve Diastolic Function - A Narrative Review

Heart failure is one of the main causes of morbidity and mortality around the globe. Heart failure with preserved ejection fraction is primarily caused by diastolic dysfunction. Adipose tissue deposition in the heart has been previously explained in the pathogenesis of diastolic dysfunction. In this article, we aim to discuss the potential interventions that can reduce the risk of diastolic dysfunction by reducing cardiac adipose tissue. A healthy diet with reduced dietary fat content can reduce visceral adiposity and improve diastolic function. Aerobic and resistance exercises also reduce visceral and epicardial fat and ameliorate diastolic dysfunction. Some medications, include metformin, glucagon-like peptide-1 analogues, dipeptidyl peptidase-4 inhibitors, thiazolidinediones, sodium-glucose co-transporter-2, inhibitors, statins, ACE-Is, and ARBs, have shown different degrees of effectiveness in improving cardiac steatosis and diastolic function. Bariatric surgery has also shown promising results in this field.

A high-sucrose diet exacerbates the left ventricular phenotype in a high fat-fed streptozotocin rat model of diabetic cardiomyopathy

Left ventricular (LV) dysfunction is an early, clinically detectable sign of cardiomyopathy in type 2 diabetes mellitus (T2DM) that precedes the development of symptomatic heart failure. Preclinical models of diabetic cardiomyopathy are essential to develop therapies that may prevent or delay the progression of heart failure. This study examined the molecular, structural, and functional cardiac phenotype of two rat models of T2DM induced by a high-fat diet (HFD) with a moderate- or high-sucrose content (containing 88.9 or 346 g/kg sucrose, respectively), plus administration of low-dose streptozotocin (STZ). At 8 wk of age, male Sprague-Dawley rats commenced a moderate- or high-sucrose HFD. Two weeks later, rats received low-dose STZ (35 mg/kg ip for 2 days) and remained on their respective diets. LV function was assessed by echocardiography 1 wk before end point. At 22 wk of age, blood and tissues were collected postmortem. Relative to chow-fed sham rats, diabetic rats on a moderate- or high-sucrose HFD displayed cardiac reactive oxygen species dysregulation, perivascular fibrosis, and impaired LV diastolic function. The diabetes-induced impact on LV adverse remodeling and diastolic dysfunction was more apparent when a high-sucrose HFD was superimposed on STZ. In conclusion, a high-sucrose HFD in combination with low-dose STZ produced a cardiac phenotype that more closely resembled T2DM-induced cardiomyopathy than STZ diabetic rats subjected to a moderate-sucrose HFD.NEW & NOTEWORTHY Left ventricular dysfunction and adverse remodeling were more pronounced in diabetic rats that received low-dose streptozotocin (STZ) and a high-sucrose high-fat diet (HFD) compared with those on a moderate-sucrose HFD in combination with STZ. Our findings highlight the importance of sucrose content in diet composition, particularly in preclinical studies of diabetic cardiomyopathy, and demonstrate that low-dose STZ combined with a high-sucrose HFD is an appropriate rodent model of cardiomyopathy in type 2 diabetes.

Change in left ventricular diastolic function after pioglitazone treatment in patients with type 2 diabetes mellitus: A protocol for systematic review and meta-analysis

BACKGROUND

Pioglitazone is currently used as an anti-diabetic agent and can reduce cardiovascular events in in patients with type 2 diabetes mellitus (T2DM). Left ventricular diastolic dysfunction has been recognized as an early manifestation of myocardial dysfunction in T2DM patients. This systematic review and meta-analysis aimed to investigate changes in the left ventricular diastolic function after the treatment of pioglitazone.

METHODS

A systematic literature search of PubMed, Embase, and the Cochrane Library until May 2021 with keywords pioglitazone and left ventricular diastolic function was performed in accordance with the meta-analysis of observational studies in epidemiology guidelines and preferred reporting items for systematic reviews and meta-analyses statement. Three reviewers independently selected the studies and extracted data. Quality assessment of the included studies was undergone. A fixed effects model was used to calculate overall effect sizes. Subgroup analyses were subsequently performed. A fixed effects model was used to calculate the overall effect size. Subgroup analyses were then performed.

RESULTS

Seven studies with 233 patients were investigated. We found pioglitazone significantly improved hemoglobin A1c (%) in patients with T2DM and left ventricular diastolic function had an improvement tendency (weighted mean difference [WMD], 0.03; 95% confidence interval [CI], 0.01-0.05, P < .01) despite moderate heterogeneity (I2 = 66%). Subsequent subgroup analysis indicated that left ventricular diastolic function were significantly improved (WMD, 0.20; 95% CI, 0.12-0.29, P < .001) in T2DM patients whose average age < 55 after receiving pioglitazone treatment. However, in T2DM patients with mean age ≥ 55 years, there was no significant improvement of left ventricular diastolic function (WMD, 0.02; 95% CI, 0-0.04, P = .04).

CONCLUSION

Pioglitazone treatment significantly improved left ventricular diastolic function in type 2 diabetic patients with a mean age of < 55 years, but did not improve left ventricular diastolic function in patients with a mean age of ≥ 55 years.

Prospective Longitudinal Characterization of the Relationship between Diabetes and Cardiac Structural and Functional Changes

OBJECTIVES

In a cohort of type 2 diabetic (T2D) patients who underwent baseline cardiac magnetic resonance (CMR) and biomarker testing, during a median follow-up of 6 years, we aimed to determine longitudinal changes in the phenotypic expression of heart disease in diabetes, report clinical outcomes, and compare baseline clinical characteristics and CMR findings of patients who experienced major adverse cardiovascular events (MACE) to those remaining MACE free.

BACKGROUND

T2D increases the risk of heart failure (HF) and cardiovascular mortality. The long-term impact of T2D on cardiac phenotype in the absence of cardiovascular disease and other clinical events is unknown.

METHODS

Patients with T2D (n = 100) with no history of cardiovascular disease or hypertension were recruited at baseline. Biventricular volumes, function, and myocardial extracellular volume fraction (ECV) were assessed by CMR, and blood biomarkers were taken. Follow-up CMR was repeated in those without interim clinical events after 6 years.

RESULTS

Follow-up was successful in 83 participants. Of those, 29 experienced cardiovascular/clinical events (36%). Of the remaining 59, 32 patients who experienced no events received follow-up CMR. In this cohort, despite no significant changes in blood pressure, weight, or glycated hemoglobin, significant reductions in biventricular end-diastolic volumes and ejection fractions occurred over time. The mean ECV was unchanged. Baseline plasma high-sensitivity cardiac troponin T (hs-cTnT) was significantly associated with a change in left ventricular (LV) ejection fraction. Patients who experienced MACE had higher LV mass and greater LV concentricity than those who remained event free.

CONCLUSIONS

T2D results in reductions in biventricular size and systolic function over time even in the absence of cardiovascular/clinical events.

Mechanisms and Therapeutic Prospects of Diabetic Cardiomyopathy Through the Inflammatory Response

The incidence of heart failure (HF) continues to increase rapidly in patients with diabetes. It is marked by myocardial remodeling, including fibrosis, hypertrophy, and cell death, leading to diastolic dysfunction with or without systolic dysfunction. Diabetic cardiomyopathy (DCM) is a distinct myocardial disease in the absence of coronary artery disease. DCM is partially induced by chronic systemic inflammation, underpinned by a hostile environment due to hyperglycemia, hyperlipidemia, hyperinsulinemia, and insulin resistance. The detrimental role of leukocytes, cytokines, and chemokines is evident in the diabetic heart, yet the precise role of inflammation as a cause or consequence of DCM remains incompletely understood. Here, we provide a concise review of the inflammatory signaling mechanisms contributing to the clinical complications of diabetes-associated HF. Overall, the impact of inflammation on the onset and development of DCM suggests the potential benefits of targeting inflammatory cascades to prevent DCM. This review is tailored to outline the known effects of the current anti-diabetic drugs, anti-inflammatory therapies, and natural compounds on inflammation, which mitigate HF progression in diabetic populations.

Rethinking pioglitazone as a cardioprotective agent: a new perspective on an overlooked drug

Since 1985, the thiazolidinedione pioglitazone has been widely used as an insulin sensitizer drug for type 2 diabetes mellitus (T2DM). Although fluid retention was early recognized as a safety concern, data from clinical trials have not provided conclusive evidence for a benefit or a harm on cardiac function, leaving the question unanswered. We reviewed the available evidence encompassing both in vitro and in vivo studies in tissues, isolated organs, animals and humans, including the evidence generated by major clinical trials. Despite the increased risk of hospitalization for heart failure due to fluid retention, pioglitazone is consistently associated with reduced risk of myocardial infarction and ischemic stroke both in primary and secondary prevention, without any proven direct harm on the myocardium. Moreover, it reduces atherosclerosis progression, in-stent restenosis after coronary stent implantation, progression rate from persistent to permanent atrial fibrillation, and reablation rate in diabetic patients with paroxysmal atrial fibrillation after catheter ablation. In fact, human and animal studies consistently report direct beneficial effects on cardiomyocytes electrophysiology, energetic metabolism, ischemia–reperfusion injury, cardiac remodeling, neurohormonal activation, pulmonary circulation and biventricular systo-diastolic functions. The mechanisms involved may rely either on anti-remodeling properties (endothelium protective, inflammation-modulating, anti-proliferative and anti-fibrotic properties) and/or on metabolic (adipose tissue metabolism, increased HDL cholesterol) and neurohormonal (renin–angiotensin–aldosterone system, sympathetic nervous system, and adiponectin) modulation of the cardiovascular system. With appropriate prescription and titration, pioglitazone remains a useful tool in the arsenal of the clinical diabetologist.

Effects of oral antidiabetic drugs and glucagon-like peptide-1 receptor agonists on left ventricular diastolic function in patients with type 2 diabetes mellitus: a systematic review and network meta-analysis

The present study aimed to compare the effects of oral antidiabetic drugs (OADs) and glucagon-like peptide-1 receptor agonists (GLP-1RAs) on left ventricular diastolic function in patients with type 2 diabetes mellitus using a network meta-analysis of randomized controlled trials (RCTs). Literature searches were conducted on Medline, the Cochrane Controlled Trials Registry, and ClinicalTrials.gov . RCTs that assessed the effects on left ventricular diastolic function of OADs and GLP-1RAs in patients with type 2 diabetes were included. The outcome was the value (E/e') obtained by dividing peak early diastolic transmitral flow velocity (E) by the mitral annular early diastolic velocity (e'). Standardized mean differences (SMD) and 95% confidence intervals (CIs) were calculated from a random-effects network meta-analysis. Eight RCTs (592 patients) identified in a literature search met the eligibility criteria for this study and were included in the network meta-analysis. Compared with placebo, liraglutide was the only drug that caused a significant improvement in left ventricular diastolic function (SMD, - 0.65; 95% CI, - 1.23 to - 0.08). In addition, when the effects on left ventricular diastolic function were evaluated across drugs, liraglutide alone caused a significant improvement in left ventricular diastolic function compared with OADs (sitagliptin, linagliptin, pioglitazone, rosiglitazone, voglibose, and glimepiride). From the perspective of preventing the onset of heart failure, the administration of liraglutide for type 2 diabetes is promising.

Effects of antidiabetic drugs on left ventricular function/dysfunction: a systematic review and network meta-analysis

BACKGROUND

Although a variety of antidiabetic drugs have significant protective action on the cardiovascular system, it is still unclear which antidiabetic drugs can improve ventricular remodeling and fundamentally delay the process of heart failure. The purpose of this network meta-analysis is to compare the efficacy of sodium glucose cotransporter type 2 (SGLT-2) inhibitors, dipeptidyl peptidase-4 (DPP-4) inhibitors, glucagon-like peptide-1 (GLP-1) agonists, metformin (MET), sulfonylurea (SU) and thiazolidinediones (TZDs) in improving left ventricular (LV) remodeling in patients with type 2 diabetes (T2DM) and/or cardiovascular disease (CVD).

METHODS

We searched articles published before October 18, 2019, regardless of language or data, in 4 electronic databases: PubMed, EMBASE, Cochrane Library and Web of Science. We included randomized controlled trials in this network meta-analysis, as well as a small number of cohort studies. The differences in the mean changes in left ventricular echocardiographic parameters between the treatment group and control group were evaluated.

RESULTS

The difference in the mean change in LV ejection fraction (LVEF) between GLP-1 agonists and placebo in treatment effect was greater than zero (MD = 2.04% [0.64%, 3.43%]); similar results were observed for the difference in the mean change in LV end-diastolic diameter (LVEDD) between SGLT-2 inhibitors and placebo (MD = - 3.3 mm [5.31, - 5.29]), the difference in the mean change in LV end-systolic volume (LVESV) between GLP-1 agonists and placebo (MD = - 4.39 ml [- 8.09, - 0.7]); the difference in the mean change in E/e' between GLP-1 agonists and placebo (MD = - 1.05[- 1.78, - 0.32]); and the difference in the mean change in E/e' between SGLT-2 inhibitors and placebo (MD = - 1.91[- 3.39, - 0.43]).

CONCLUSIONS

GLP-1 agonists are more significantly associated with improved LVEF, LVESV and E/e', SGLT-2 inhibitors are more significantly associated with improved LVEDD and E/e', and DPP-4 inhibitors are more strongly associated with a negative impact on LV end-diastolic volume (LVEDV) than are placebos. SGLT-2 inhibitors are superior to other drugs in pairwise comparisons.

Interrelationship between diabetes mellitus and heart failure: the role of peroxisome proliferator-activated receptors in left ventricle performance

Heart failure (HF) is a common cardiac syndrome, whose pathophysiology involves complex mechanisms, some of which remain unknown. Diabetes mellitus (DM) constitutes not only a glucose metabolic disorder accompanied by insulin resistance but also a risk factor for cardiovascular disease and HF. During the last years though emerging data set up, a bidirectional interrelationship between these two entities. In the case of DM impaired calcium homeostasis, free fatty acid metabolism, redox state, and advance glycation end products may accelerate cardiac dysfunction. On the other hand, when HF exists, hypoperfusion of the liver and pancreas, b-blocker and diuretic treatment, and autonomic nervous system dysfunction may cause impairment of glucose metabolism. These molecular pathways may be used as therapeutic targets for novel antidiabetic agents. Peroxisome proliferator-activated receptors (PPARs) not only improve insulin resistance and glucose and lipid metabolism but also manifest a diversity of actions directly or indirectly associated with systolic or diastolic performance of left ventricle and symptoms of HF. Interestingly, they may beneficially affect remodeling of the left ventricle, fibrosis, and diastolic performance but they may cause impaired water handing, sodium retention, and decompensation of HF which should be taken into consideration in the management of patients with DM. In this review article, we present the pathophysiological data linking HF with DM and we focus on the molecular mechanisms of PPARs agonists in left ventricle systolic and diastolic performance providing useful insights in the molecular mechanism of this class of metabolically active regiments.

Effects of oral antidiabetic drugs on left ventricular mass in patients with type 2 diabetes mellitus: a network meta-analysis

Background

We used a network meta-analysis of randomized controlled trials (RCTs) to comparatively examine the effects of oral antidiabetic drugs (OADs) on left ventricular mass (LVM) in patients with type 2 diabetes.

Methods

Document searches were implemented using Medline, Cochrane Controlled Trials Registry, and ClinicalTrials.gov. We decided to include RCTs that evaluated the impact of LVM using the administration of OADs to patients with type 2 diabetes. The outcome evaluations used standardized mean difference (SMD) and 95% confidence intervals (CIs). We then performed a comparative examination of LVM related to the administration of OADs using random effects network meta-analysis.

Results

The document search found 11 RCTs (1410 people) that satisfied the eligibility criteria for this study, and these RCTs were incorporated into the network meta-analysis. The only medication that significantly reduced LVM compared to a placebo was gliclazide (SMD, −1.09; 95% CI, −1.62 to  − 0.57). Further, when comparing the impact on LVM between OADs, only gliclazide significantly reduced LVM compared to other OADs (glyburide, voglibose, metformin, pioglitazone, rosiglitazone, and sitagliptin).

Conclusions

In the present study, gliclazide was the only medication that significantly reduced LVM in patients with type 2 diabetes. When considered from the perspective of causing heart failure and preventing recurrence, it is possible that the use of gliclazide in patients with type 2 diabetes will provide multiple benefits.

The Effect of Metformin on Diastolic Function in Patients Presenting with ST-Elevation Myocardial Infarction

Introduction

Diastolic dysfunction is an important predictor of poor outcome after myocardial infarction. Metformin treatment improved diastolic function in animal models and patients with diabetes. Whether metformin improves diastolic function in patients presenting with ST-segment elevation myocardial infarction (STEMI) is unknown.

Methods

The GIPS-III trial randomized STEMI patients, without known diabetes, to metformin or placebo initiated directly after PCI. The previously reported primary endpoint was left ventricular ejection fraction at 4 months, which was unaffected by metformin treatment. This is a predefined substudy to determine an effect of metformin on diastolic function. For this substudy trans-thoracic echocardiography was performed during hospitalization and after 4 months. Diastolic dysfunction was defined as having the combination of a functional alteration (i.e. decreased tissue velocity: mean of septal e’ and lateral e’) and a structural alteration (i.e. increased left atrial volume index (LAVI)). In addition, left ventricular mass index and transmitral flow velocity (E) to mean e' ratio (E/e’) were measured to determine an effect of metformin on individual echocardiographic markers of diastolic function.

Results

In 237 (63%) patients included in the GIPS-III trial diastolic function was measured during hospitalization as well as at 4 months. Diastolic dysfunction was present in 11 (9%) of patients on metformin and 11 (9%) patients on placebo treatment (P = 0.98) during hospitalization. After 4 months 22 (19%) of patients with metformin and 18 (15%) patients with placebo (P = 0.47) had diastolic dysfunction. In addition, metformin did not improve any of the individual echocardiographic markers of diastolic function.

Conclusions

In contrast to experimental and observational data, our randomized placebo controlled trial did not suggest a beneficial effect of short-term metformin treatment on diastolic function in STEMI patients.

Does Thiazolidinedione therapy exacerbate fluid retention in congestive heart failure?

The ever-growing global burden of congestive heart failure (CHF) and type 2 diabetes mellitus (T2DM) as well as their co-existence necessitate that anti-diabetic pharmacotherapy will modulate the cardiovascular risk inherent to T2DM while complying with the accompanying restrictions imposed by CHF. The thiazolidinedione (TZD) family of peroxisome proliferator-activated receptor γ (PPARγ) agonists initially provided a promising therapeutic option in T2DM owing to anti-diabetic efficacy combined with pleiotropic beneficial cardiovascular effects. However, the utility of TZDs in T2DM has declined in the past decade, largely due to concomitant adverse effects of fluid retention and edema formation attributed to salt-retaining effects of PPARγ activation on the nephron. Presumably, the latter effects are potentially deleterious in the context of pre-existing fluid retention in CHF. However, despite a considerable body of evidence on mechanisms responsible for TZD-induced fluid retention suggesting that this class of drugs is rightfully prohibited from use in CHF patients, there is a paucity of experimental and clinical studies that investigate the effects of TZDs on salt and water homeostasis in the CHF setting. In an attempt to elucidate whether TZDs actually exacerbate the pre-existing fluid retention in CHF, our review summarizes the pathophysiology of fluid retention in CHF. Moreover, we thoroughly review the available data on TZD-induced fluid retention and proposed mechanisms in animals and patients. Finally, we will present recent studies challenging the common notion that TZDs worsen renal salt and water retention in CHF.

Dipeptidyl peptidase inhibition prevents diastolic dysfunction and reduces myocardial fibrosis in a mouse model of Western diet induced obesity

OBJECTIVE

Consumption of a high-fat/high-fructose Western diet (WD) is linked to rising obesity and heart disease, particularly diastolic dysfunction which characterizes early obesity/metabolic cardiomyopathy. Mounting evidence supports a role for inflammation, oxidative stress and fibrosis in the pathophysiology of metabolic cardiomyopathy. Dipeptidyl peptidase-4 (DPP-4) is a circulating exopeptidase recently reported to be elevated in the plasma of patients with insulin resistance (IR), obesity and heart failure. We hypothesized that a model of WD induced obesity/metabolic cardiomyopathy would exhibit increased DPP-4 activity and cardiac fibrosis with DPP-4 inhibition preventing cardiac fibrosis and the associated diastolic dysfunction.

MATERIALS/METHODS

Four-week-old C57BL6/J mice were fed a high-fat/high-fructose WD with the DPP-4 inhibitor MK0626 for 16 weeks. Cardiac function was examined by high-resolution cine-cardiac magnetic resonance imaging (MRI). Phenotypic analysis included measurements of body and heart weight, systemic IR and DPP-4 activity. Immunohistochemistry and transmission electron microscopy (TEM) were utilized to identify underlying pathologic mechanisms.

RESULTS

We found that chronic WD consumption caused obesity, IR, elevated plasma DPP-4 activity, heart enlargement and diastolic dysfunction. DPP-4 inhibition with MK0626 in WD fed mice resulted in >75% reduction in plasma DPP-4 activity, improved IR and normalized diastolic relaxation. WD consumption induced myocardial oxidant stress and fibrosis with amelioration by MK0626. TEM of hearts from WD fed mice revealed abnormal mitochondrial and perivascular ultrastructure partially corrected by MK0626.

CONCLUSIONS

This study provides evidence of a role for increased DPP-4 activity in metabolic cardiomyopathy and a potential role for DPP-4 inhibition in prevention and/or correction of oxidant stress/fibrosis and associated diastolic dysfunction.

Plasma glucose levels and left ventricular diastolic function in nondiabetic hypertensive patients

BACKGROUND

Changes in left ventricular (LV) diastolic filling anticipate diastolic heart failure and are frequently detected in patients with hypertension or diabetes. We tested the hypothesis that increased fasting and postload glucose levels are associated with diastolic dysfunction as assessed by tissue Doppler imaging (TDI) in hypertensive patients.

METHODS

In 104 untreated, nondiabetic, hypertensive patients free of cardiovascular complications, we measured glucose and insulin at fast and after an oral glucose load, calculated the Homeostatic Model Assessment (HOMA) index, and performed electrocardiogram (ECG), conventional echocardiography, and TDI.

RESULTS

Thirty-one patients who had impaired fasting glucose/impaired glucose tolerance had more frequent LV strain at ECG and worse TDI markers of diastolic function than patients with normal plasma glucose but no differences in variables LV mass, LV geometry, systolic function, and early-/late-wave transmitral diastolic velocity. TDI detected diastolic dysfunction in 46 patients who were older and had greater body mass index, blood pressure, fasting and postload glucose, insulin, HOMA index, LV mass, and left atrial diameter than patients with preserved diastolic function. Variables of diastolic function measured at TDI were significantly related with age, body mass index, LV mass, and fasting and postload plasma glucose. Stepwise regression analysis showed that the relationship of markers of diastolic dysfunction with both fasting and postload glucose levels was independent of possible confounders.

CONCLUSIONS

Initially abnormal fasting and postload glucose levels are associated with more prominent diastolic impairment in uncomplicated hypertensive patients, suggesting that hyperglycemia might increase the risk of diastolic heart failure even in the absence of diabetes.

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.

Update on diabetic cardiomyopathy: inches forward, miles to go

Diabetes causes cardiomyopathy, both directly and by potentiating the effect of its common comorbidities, coronary artery disease and hypertension, on its development. With the common and growing prevalence of diabetes worldwide, diabetic cardiomyopathy is a significant public health problem. Recent research identifies both mitochondrial dysfunction and epigenetic effects as newly recognized factors in the complex pathogenesis of diabetic cardiomyopathy. Diagnostically, specialized echocardiography techniques, cardiac magnetic resonance imaging, and serologic biomarkers all appear to have promise in detecting the early stages of diabetic cardiomyopathy. Research into treatments includes both traditional diabetes and heart failure therapies, but also explores the potential of newer metabolic and anti-inflammatory agents. These recent insights provide important additions to our knowledge about diabetic cardiomyopathy, but much remains unknown.

Exercise attenuates the premature cardiovascular aging effects of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2D) is an example of a disease process that results in decrements in function additional to those imposed by the inexorable 'primary aging' process. These decrements due to disease, rather than primary aging, can be termed 'secondary aging', and include the premature development (as early as adolescence) of asymptomatic preclinical cardiovascular abnormalities (e.g. endothelial dysfunction, arterial stiffness, diastolic dysfunction), as well as impaired exercise performance. These abnormalities are important, as they are associated with greater cardiovascular morbidity and mortality in people with and without T2D. A better understanding of the pathophysiology of secondary cardiovascular aging in people with T2D is warranted, and an evaluation of the benefits of existing treatments for these abnormalities is useful (e.g. exercise training). The focus of this review is to discuss the data relevant to the following key postulates: (a) T2D causes premature cardiovascular aging; (b) in contrast to primary cardiovascular aging, the premature cardiovascular aging of T2D may be modifiable with exercise. The exercise-focused perspective for this review is appropriate because impairments in exercise performance are markers of premature cardiovascular aging in T2D, and also because exercise training shows promise to attenuate some aspects of cardiovascular aging during the preclinical stage.

Double-blind, randomized, multicentre, and active comparator controlled investigation of the effect of pioglitazone, metformin, and the combination of both on cardiovascular risk in patients with type 2 diabetes receiving stable basal insulin therapy: the PIOCOMB study

BACKGROUND

We analyzed specific effects of an add-on therapy with pioglitazone compared to metformin and their combination in patients with basal insulin treatment on biomarkers of CV risk.

METHODS

In this double-blind, randomized, multicentre, active comparator controlled trial, 121 patients with type 2 diabetes were enrolled. Inclusions: treatment with basal insulin, HbA(1C) 6.5%-8.5%, age 30-75 years. After glargine therapy over 2 weeks for titration towards FBG ≤ 7.8 mmol/L, patients received either (A) bid 850 mg metformin (n = 42), (B) bid 15 mg pioglitazone (n = 40), or (C) 30 mg pioglitazone plus 1.7 g metformin (n = 39) over 6 months. Matrix Metal Proteinase 9 (MMP-9) was primary objective, together with biomarkers of CV risk.

RESULTS

Pioglitazone (B) reduced MMP-9 versus baseline by 54.1 ± 187.1 ng/mL, with metformin (A) it was increased by 49.6 ± 336.2 ng/mL (p = 0.0345; B vs. A), and with the combination of both (C) it was decreased by 67.8 ± 231.4 ng/mL (A vs. C: p = 0.0416; B vs. C: p = 0.8695). After logarithmic transformation due to high variances the exploratory results showed significance for A vs. B (p = 0.0043) and for A vs. C (p = 0.0289).Insulin dosage was reduced by 7.3 units in group B (p < 0.0001), by 6.0 units in C (p = 0.0004), but was increased by 2.5 units (p = 0.1539) in A at follow up. Reduction in hs-CRP was significant within treatment groups for B (p = 0.0098) and C (p < 0.0001), and between the groups for A vs. C (p = 0.0124). All three single regimens reduced PAI-1. Adiponectin was significantly elevated in B and C (p < 0.0001) and between-groups. HbA(1C) was only significantly decreased in the combination group. No significant effects were observed for NFkB and PGFα. peripheral edema were seen in 11.9% vs. 40.0% vs. 20.5%, and weight change was -0.7 kg vs. +4.3 kg vs. +2.7 kg (A vs. B vs. C).

CONCLUSIONS

Addition of pioglitazone but not of metformin reduces MMP-9, hs-CRP and increased insulin sensitivity and adiponectin in this study. The combination of both had no additional effect on inflammation. Pioglitazone is suggested to be a rational add-on therapy to basal insulin in patients with high CV risk.

Management of cardiovascular risk factors with pioglitazone combination therapies in type 2 diabetes: an observational cohort study

Background

Type 2 diabetes (T2D) is strongly associated with cardiovascular risk and requires medications that improve glycemic control and other cardiovascular risk factors. The authors aimed to assess the relative effectiveness of pioglitazone (Pio), metformin (Met) and any sulfonylurea (SU) combinations in non-insulin-treated T2D patients who were failing previous hypoglycemic therapy.

Methods

Over a 1-year period, two multicenter, open-labeled, controlled, 1-year, prospective, observational studies evaluated patients with T2D (n = 4585) from routine clinical practice in Spain and Greece with the same protocol. Patients were eligible if they had been prescribed Pio + SU, Pio + Met or SU + Met serving as a control cohort, once they had failed with previous therapy. Anthropometric measurements, lipid and glycemic profiles, blood pressure, and the proportions of patients at microvascular and macrovascular risk were assessed.

Results

All study treatment combinations rendered progressive 6-month and 12-month lipid, glycemic, and blood pressure improvements. Pio combinations, especially Pio + Met, were associated with increases in HDL-cholesterol and decreases in triglycerides and in the atherogenic index of plasma. The proportion of patients at high risk decreased after 12 months in all study cohorts. Minor weight changes (gain or loss) and no treatment-related fractures occurred during the study. The safety profile was good and proved similar among treatments, except for more hypoglycemic episodes in patients receiving SU and for the occurrence of edema in patients using Pio combinations. Serious cardiovascular events were rarely reported.

Conclusions

In patients with T2D failing prior hypoglycemic therapies, Pio combinations with SU or Met (especially Pio + Met) improved blood lipid and glycemic profiles, decreasing the proportion of patients with a high microvascular or macrovascular risk. The combination of Pio with SU or Met may therefore be recommended for T2D second-line therapy in the routine clinical practice, particularly in patients with dyslipidemia.