The Glitazars Paradox: Cardiotoxicity of the Metabolically Beneficial Dual PPARα and PPARγ Activation

Cardioprotection strategies for anthracycline cardiotoxicity

Thanks to the fantastic progress in cancer therapy options, there is a growing population of cancer survivors. This success has resulted in a need to focus much effort into improving the quality of life of this population. Cancer and cardiovascular disease share many common risk factors and have an interplay between them, with one condition mechanistically affecting the other and vice versa. Furthermore, widely prescribed cancer therapies have known toxic effects in the cardiovascular system. Anthracyclines are the paradigm of efficacious cancer therapy widely prescribed with a strong cardiotoxic potential. While some cancer therapies cardiovascular toxicities are transient, others are irreversible. There is a growing need to develop cardioprotective therapies that, when used in conjunction with cancer therapies, can prevent cardiovascular toxicity and thus improve long-term quality of life in survivors. The field has three main challenges: (i) identification of the ultimate mechanisms leading to cardiotoxicity to (ii) identify specific therapeutic targets, and (iii) more sensible diagnostic tools to early identify these conditions. In this review we will focus on the cardioprotective strategies tested and under investigation. We will focus this article into anthracycline cardiotoxicity since it is still the agent most widely prescribed, the one with higher toxic effects on the heart, and the most widely studied.

Podophyllotoxin via SIRT1/PPAR /NF-κB axis induced cardiac injury in rats based on the toxicological evidence chain (TEC) concept

BACKGROUND

The study of cardiotoxicity of drugs has become an important part of clinical safety evaluation of drugs. It is commonly known that podophyllotoxin (PPT) and its many derivatives and congeners are broad-spectrum pharmacologically active substances. Clinical cardiotoxicity of PPT and its derivatives has been raised, basic research on the mechanism of cardiotoxicity remains insufficient.

PURPOSE

In present study, our group's innovative concept of toxicological evidence chain (TEC) was applied to reveal the cardiac toxicity mechanism of PPT by targeted metabolomics, TMT-based quantitative proteomics and western blot.

METHODS

The injury phenotype evidence (IPE) acquired from the toxicity manifestations, such as weight and behavior observation of Sprague-Dawley rat. The damage to rat hearts were assessed through histopathological examination and myocardial enzymes levels, which were defined as Adverse Outcomes Evidence (AOE). The damage to rat hearts was assessed through histopathological examination and myocardial enzyme levels, which were defined as evidence of adverse outcomes.Overall measurements of targeted metabolomics based on energy metabolism and TMT-based quantitative proteomics were obtained after exposure to PPT to acquire the Toxic Event Evidence (TEE). The mechanism of cardiac toxicity was speculated based on the integrated analysis of targeted metabolomics and TMT-based quantitative proteomics, which was verified by western blot.

RESULTS

The results indicated that exposure to PPT could result in significant elevation of myocardial enzymes and pathological alterations in rat hearts. In addition, we found that PPT caused disorders in cardiac energy metabolism, characterized by a decrease in energy metabolism fuels. TMT-based quantitative proteomics revealed that the PPAR (Peroxisome proliferators-activated receptor) signaling pathway needs further study. It is worth noting that PPT may suppress the expression of SIRT1, subsequently inhibiting AMPK, decreasing the expression of PGC-1α, PPARα and PPARγ. This results in disorders of glucose oxidation, glycolysis and ketone body metabolism. Additionally, the increase in the expression of p-IKK and p-IκBα, leads to the nuclear translocation of NF-κB p65 from the cytosol, thus triggering inflammation.

CONCLUSION

This study comprehensively evaluated cardiac toxicity of PPT and initially revealed the mechanism of cardiotoxicity,suggesting that PPT induced disorders of energy metabolism and inflammation via SIRT1/PPAR/NF-κB axis, potentially contributing to cardiac injury.

Novel Therapeutics for Type 2 Diabetes Mellitus-A Look at the Past Decade and a Glimpse into the Future

Cardiovascular disease (CVD) and kidney disease are the main causes of morbidity and mortality in type 2 diabetes mellitus (T2DM). Globally, the incidence of T2DM continues to rise. A substantial increase in the burden of CVD and renal disease, alongside the socioeconomic implications, would be anticipated. Adopting a purely glucose-centric approach focusing only on glycemic targets is no longer adequate to mitigate the cardiovascular risks in T2DM. In the past decade, significant advancement has been achieved in expanding the pharmaceutical options for T2DM, with novel agents such as the sodium-glucose cotransporter type 2 (SGLT2) inhibitors and glucagon-like peptide receptor agonists (GLP-1 RAs) demonstrating robust evidence in cardiorenal protection. Combinatorial approaches comprising multiple pharmacotherapies combined in a single agent are an emerging and promising way to not only enhance patient adherence and improve glycemic control but also to achieve the potential synergistic effects for greater cardiorenal protection. In this review, we provide an update on the novel antidiabetic agents in the past decade, with an appraisal of the mechanisms contributing to cardiorenal protection. Additionally, we offer a glimpse into the landscape of T2DM management in the near future by providing a comprehensive summary of upcoming agents in early-phase trials.

Futile lipid cycling: from biochemistry to physiology

In the healthy state, the fat stored in our body isn't just inert. Rather, it is dynamically mobilized to maintain an adequate concentration of fatty acids (FAs) in our bloodstream. Our body tends to produce excess FAs to ensure that the FA availability is not limiting. The surplus FAs are actively re-esterified into glycerides, initiating a cycle of breakdown and resynthesis of glycerides. This cycle consumes energy without generating a new product and is commonly referred to as the 'futile lipid cycle' or the glyceride/FA cycle. Contrary to the notion that it's a wasteful process, it turns out this cycle is crucial for systemic metabolic homeostasis. It acts as a control point in intra-adipocyte and inter-organ cross-talk, a metabolic rheostat, an energy sensor and a lipid diversifying mechanism. In this Review, we discuss the metabolic regulation and physiological implications of the glyceride/FA cycle and its mechanistic underpinnings.

PPAR agonists as add-on treatment with metformin in management of type 2 diabetes: a systematic review and meta-analysis

The combination of metformin and the peroxisome proliferator-activated receptors (PPAR) agonists offers a promising avenue for managing type 2 diabetes (T2D) through their potential complementary mechanisms of action. The results from randomized controlled trials (RCT) assessing the efficacy of PPAR agonists plus metformin versus metformin alone in T2D are inconsistent, which prompted the conduct of the systematic review and meta-analysis. We searched MEDLINE and EMBASE from inception (1966) to March 2023 to identify all RCTs comparing any PPAR agonists plus metformin versus metformin alone in T2D. Categorical variables were summarized as relative risk along with 95% confidence interval (CI). Twenty RCTs enrolling a total of 6058 patients met the inclusion criteria. The certainty of evidence ranged from moderate to very low. Pooled results show that using PPAR agonist plus metformin, as compared to metformin alone, results in lower concentrations of fasting glucose [MD = - 22.07 mg/dl (95% CI - 27.17, - 16.97), HbA1c [MD = - 0.53% (95% CI - 0.67, - 0.38)], HOMA-IR [MD = - 1.26 (95% CI - 2.16, - 0.37)], and fasting insulin [MD = - 19.83 pmol/L (95% CI - 29.54, - 10.13)] without significant increase in any adverse events. Thus, synthesized evidence from RCTs demonstrates the beneficial effects of PPAR agonist add-on treatment versus metformin alone in T2D patients. In particular, novel dual PPARα/γ agonist (tesaglitazar) demonstrate efficacy in improving glycaemic and lipid concentrations, so further RCTs should be performed to elucidate the long-term outcomes and safety profile of these novel combined and personalized therapeutic strategies in the management of T2D.PROSPERO registration no. CRD42023412603.

Qiliqiangxin: A multifaceted holistic treatment for heart failure or a pharmacological probe for the identification of cardioprotective mechanisms?

The active ingredients in many traditional Chinese medicines are isoprene oligomers with a diterpenoid or triterpenoid structure, which exert cardiovascular effects by signalling through nutrient surplus and nutrient deprivation pathways. Qiliqiangxin (QLQX) is a commercial formulation of 11 different plant ingredients, whose active compounds include astragaloside IV, tanshione IIA, ginsenosides (Rb1, Rg1 and Re) and periplocymarin. In the QUEST trial, QLQX reduced the combined risk of cardiovascular death or heart failure hospitalization (hazard ratio 0.78, 95% confidence interval 0.68-0.90), based on 859 events in 3119 patients over a median of 18.2 months; the benefits were seen in patients taking foundational drugs except for sodium-glucose cotransporter 2 (SGLT2) inhibitors. Numerous experimental studies of QLQX in diverse cardiac injuries have yielded highly consistent findings. In marked abrupt cardiac injury, QLQX mitigated cardiac injury by upregulating nutrient surplus signalling through the PI3K/Akt/mTOR/HIF-1α/NRF2 pathway; the benefits of QLQX were abrogated by suppression of PI3K, Akt, mTOR, HIF-1α or NRF2. In contrast, in prolonged measured cardiac stress (as in chronic heart failure), QLQX ameliorated oxidative stress, maladaptive hypertrophy, cardiomyocyte apoptosis, and proinflammatory and profibrotic pathways, while enhancing mitochondrial health and promoting glucose and fatty acid oxidation and ATP production. These effects are achieved by an action of QLQX to upregulate nutrient deprivation signalling through SIRT1/AMPK/PGC-1α and enhanced autophagic flux. In particular, QLQX appears to enhance the interaction of PGC-1α with PPARα, possibly by direct binding to RXRα; silencing of SIRT1, PGC-1α and RXRα abrogated the favourable effects of QLQX in the heart. Since PGC-1α/RXRα is also a downstream effector of Akt/mTOR signalling, the actions of QLQX on PGC-1α/RXRα may explain its favourable effects in both acute and chronic stress. Intriguingly, the individual ingredients in QLQX - astragaloside IV, ginsenosides, and tanshione IIA - share QLQX's effects on PGC-1α/RXRα/PPARα signalling. QXQL also contains periplocymarin, a cardiac glycoside that inhibits Na+ -K+ -ATPase. Taken collectively, these observations support a conceptual framework for understanding the mechanism of action for QLQX in heart failure. The high likelihood of overlap in the mechanism of action of QLQX and SGLT2 inhibitors requires additional experimental studies and clinical trials.

Pharmaceutical Strategies to Improve Druggability of Potential Drug Candidates in Nonalcoholic Fatty Liver Disease Therapy

Nonalcoholic fatty liver disease (NAFLD) has become globally prevalent and is the leading cause of chronic liver disease. Although NAFLD is reversible without medical intervention in the early stage, the condition could be sequentially worsened to nonalcoholic steatohepatitis (NASH) and, eventually, cirrhosis and hepatic cancer. The progression of NAFLD is related to various factors such as genetics, pre-disposed metabolic disorders, and immunologic factors. Thankfully, to date, there have been accumulating research efforts and, as a result, different classes of potent drug candidates have been discovered. In addition, there have also been various attempts to explore pharmaceutical strategies to improve the druggability of drug candidates. In this review, we provided a brief overview of the drug candidates that have undergone clinical trials. In the latter part, strategies for developing better drugs are discussed.

Terpene-Containing Analogues of Glitazars as Potential Therapeutic Agents for Metabolic Syndrome

Metabolic syndrome is a complex of abnormalities involving impaired glucose and lipid metabolism, which needs effective pharmacotherapy. One way to reduce lipid and glucose levels associated with this pathology is the simultaneous activation of nuclear PPAR-alpha and gamma. For this purpose, we synthesized a number of potential agonists based on the pharmacophore fragment of glitazars with the inclusion of mono- or diterpenic moiety in the molecular structure. The study of their pharmacological activity in mice with obesity and type 2 diabetes mellitus (C57Bl/6^Ay) revealed one substance that was capable of reducing the triglyceride levels in the liver and adipose tissue of mice by enhancing their catabolism and expressing a hypoglycemic effect connected with the sensitization of mice tissue to insulin. It has also been shown to have no toxic effects on the liver.

Design of Improved Antidiabetic Drugs: A Journey from Single to Multitarget Agents

Multifactorial diseases exhibit a complex pathophysiology with several factors contributing to their pathogenesis and development. Examples of such disorders are neurodegenerative (e. g. Alzheimer's, Parkinson's) and cardiovascular diseases (e. g. atherosclerosis, metabolic syndrome, diabetes II). Traditional therapeutic approaches with single-target drugs have been proven, in many cases, unsatisfactory for the treatment of multifactorial diseases such as diabetes II. The well-established by now strategy of multitarget drugs is constantly gaining interest and momentum, as a more effective approach. The development of pharmacomolecules able to simultaneously modulate multiple relevant-to-the-disease targets has already several successful examples in various fields and has, as such, inspired the design of multitarget antidiabetic agents; this review highlights the design aspect and efficacy of this approach for improved antidiabetics by presenting several examples of successful pharmacophore combinations in (multitarget) agents that modulate two or more molecular targets involved in diabetes II, resulting in a superior antihyperglycemic profile.

Prediction of drug-induced liver injury and cardiotoxicity using chemical structure and in vitro assay data

Drug-induced liver injury (DILI) and cardiotoxicity (DICT) are major adverse effects triggered by many clinically important drugs. To provide an alternative to in vivo toxicity testing, the U.S. Tox21 consortium has screened a collection of ∼10K compounds, including drugs in clinical use, against >70 cell-based assays in a quantitative high-throughput screening (qHTS) format. In this study, we compiled reference compound lists for DILI and DICT and compared the potential of Tox21 assay data with chemical structure information in building prediction models for human in vivo hepatotoxicity and cardiotoxicity. Models were built with four different machine learning algorithms (e.g., Random Forest, Naïve Bayes, eXtreme Gradient Boosting, and Support Vector Machine) and model performance was evaluated by calculating the area under the receiver operating characteristic curve (AUC-ROC). Chemical structure-based models showed reasonable predictive power for DILI (best AUC-ROC = 0.75 ± 0.03) and DICT (best AUC-ROC = 0.83 ± 0.03), while Tox21 assay data alone only showed better than random performance. DILI and DICT prediction models built using a combination of assay data and chemical structure information did not have a positive impact on model performance. The suboptimal predictive performance of the assay data is likely due to insufficient coverage of an adequately predictive number of toxicity mechanisms. The Tox21 consortium is currently expanding coverage of biological response space with additional assays that probe toxicologically important targets and under-represented pathways that may improve the prediction of in vivo toxicity such as DILI and DICT.

In vitro activity of a panel of per- and polyfluoroalkyl substances (PFAS), fatty acids, and pharmaceuticals in peroxisome proliferator-activated receptor (PPAR) alpha, PPAR gamma, and estrogen receptor assays

Data demonstrate numerous per- and polyfluoroalkyl substances (PFAS) activate peroxisome proliferator-activated receptor alpha (PPARα), however, additional work is needed to characterize PFAS activity on PPAR gamma (PPARγ) and other nuclear receptors. We utilized in vitro assays with either human or rat PPARα or PPARγ ligand binding domains to evaluate 16 PFAS (HFPO-DA, HFPO-DA-AS, NBP2, PFMOAA, PFHxA, PFOA, PFNA, PFDA, PFOS, PFBS, PFHxS, PFOSA, EtPFOSA, and 4:2, 6:2 and 8:2 FTOH), 3 endogenous fatty acids (oleic, linoleic, and octanoic), and 3 pharmaceuticals (WY14643, clofibrate, and the metabolite clofibric acid). We also tested chemicals for human estrogen receptor (hER) transcriptional activation. Nearly all compounds activated both PPARα and PPARγ in both human and rat ligand binding domain assays, except for the FTOH compounds and PFOSA. Receptor activation and relative potencies were evaluated based on effect concentration 20% (EC20), top percent of max fold induction (pmaxtop), and area under the curve (AUC). HFPO-DA and HFPO-DA-AS were the most potent (lowest EC20, highest pmaxtop and AUC) of all PFAS in rat and human PPARα assays, being slightly less potent than oleic and linoleic acid, while NBP2 was the most potent in rat and human PPARγ assays. Only PFHxS, 8:2 and 6:2 FTOH exhibited hER agonism >20% pmax. In vitro measures of human and rat PPARα and PPARγ activity did not correlate with oral doses or serum concentrations of PFAS that induced increases in male rat liver weight from the National Toxicology Program 28-d toxicity studies. Data indicate that both PPARα and PPARγ activation may be molecular initiating events that contribute to the in vivo effects observed for many PFAS.

Functional and Structural Insights into Human PPARα/δ/γ Subtype Selectivity of Bezafibrate, Fenofibric Acid, and Pemafibrate

Among the agonists against three peroxisome proliferator-activated receptor (PPAR) subtypes, those against PPARα (fibrates) and PPARγ (glitazones) are currently used to treat dyslipidemia and type 2 diabetes, respectively, whereas PPARδ agonists are expected to be the next-generation metabolic disease drug. In addition, some dual/pan PPAR agonists are currently being investigated via clinical trials as one of the first curative drugs against nonalcoholic fatty liver disease (NAFLD). Because PPARα/δ/γ share considerable amino acid identity and three-dimensional structures, especially in ligand-binding domains (LBDs), clinically approved fibrates, such as bezafibrate, fenofibric acid, and pemafibrate, could also act on PPARδ/γ when used as anti-NAFLD drugs. Therefore, this study examined their PPARα/δ/γ selectivity using three independent assays—a dual luciferase-based GAL4 transactivation assay for COS-7 cells, time-resolved fluorescence resonance energy transfer-based coactivator recruitment assay, and circular dichroism spectroscopy-based thermostability assay. Although the efficacy and efficiency highly varied between agonists, assay types, and PPAR subtypes, the three fibrates, except fenofibric acid that did not affect PPARδ-mediated transactivation and coactivator recruitment, activated all PPAR subtypes in those assays. Furthermore, we aimed to obtain cocrystal structures of PPARδ/γ-LBD and the three fibrates via X-ray diffraction and versatile crystallization methods, which we recently used to obtain 34 structures of PPARα-LBD cocrystallized with 17 ligands, including the fibrates. We herein reveal five novel high-resolution structures of PPARδ/γ–bezafibrate, PPARγ–fenofibric acid, and PPARδ/γ–pemafibrate, thereby providing the molecular basis for their application beyond dyslipidemia treatment.

Network-driven targeted analysis reveals that Astragali Radix alleviates doxorubicin-induced cardiotoxicity by maintaining fatty acid homeostasis

ETHNOPHARMACOLOGICAL RELEVANCE

Astragali Radix (AR) is a popular traditional Chinese medicine that has been used for more than 2000 years. It is a well-known tonic for weak people with chronic diseases, such as heart failure and cerebral ischemia. Previous studies have reported that AR could support the "weak heart" of cancer patients who suffered from doxorubicin (DOX)-induced cardiotoxicity (DIC). However, the underlying mechanism remains unclear.

AIM OF THE STUDY

This study aimed to uncover the critical pathways and molecular determinants for AR against DIC by fully characterizing the network-based relationship.

MATERIALS AND METHODS

We integrated ultra-high-performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS) profiling, database and literature searching, and the human protein-protein interactome to discover the specific network module associated with AR against DIC. To validate the network-based findings, a low-dose, long-term DIC mouse model and rat cardiomyoblast H9c2 cells were employed. The levels of potential key metabolites and proteins in hearts and cells were quantified by the LC-MS/MS targeted analysis and western blotting, respectively.

RESULTS

We constructed one of the most comprehensive AR component-target network described to date, which included 730 interactions connecting 64 unique components and 359 unique targets. Relying on the network-based evaluation, we identified fatty acid metabolism as a putative critical pathway and peroxisome proliferator-activated receptors (PPARα and PPARγ) as potential molecular determinants. We then confirmed that DOX caused the accumulation of fatty acids in the mouse failing heart, while AR promoted fatty acid metabolism and preserved heart function. By inhibiting PPARγ in H9c2 cells, we further found that AR could alleviate DIC by activating PPARγ to maintain fatty acid homeostasis.

CONCLUSIONS

Our findings imply that AR is a promising drug candidate that treats DIC by maintaining fatty acid homeostasis. More importantly, the network-based method developed here could facilitate the mechanism discovery of AR therapy and help catalyze innovation in its clinical application.

Structural Basis for PPARs Activation by The Dual PPARα/γ Agonist Sanguinarine: A Unique Mode of Ligand Recognition

Peroxisome proliferator-activated receptors (PPARs) play crucial roles in glucose and lipid metabolism and inflammation. Sanguinarine is a natural product that is isolated from Sanguinaria Canadensis, a potential therapeutic agent for intervention in chronic diseases. In this study, biochemical and cell-based promoter-reporter gene assays revealed that sanguinarine activated both PPARα and PPARγ, and enhanced their transcriptional activity; thus, sanguinarine was identified as a dual agonist of PPARα/γ. Similar to fenofibrate, sanguinarine upregulates the expression of PPARα-target genes in hepatocytes. Sanguinarine also modulates the expression of key PPARγ-target genes and promotes adipocyte differentiation, but with a lower adipogenic activity compared with rosiglitazone. We report the crystal structure of sanguinarine bound to PPARα, which reveals a unique ligand-binding mode of sanguinarine, dissimilar to the classic Y-shaped binding pocket, which may represent a new pharmacophore that can be optimized for selectively targeting PPARα. Further structural and functional studies uncover the molecular basis for the selectivity of sanguinarine toward PPARα/γ among all three PPARs. In summary, our study identifies a PPARα/γ dual agonist with a unique ligand-binding mode, and provides a promising and viable novel template for the design of dual-targeting PPARs ligands.

Untangling the Cooperative Role of Nuclear Receptors in Cardiovascular Physiology and Disease

The heart is the first organ to acquire its physiological function during development, enabling it to supply the organism with oxygen and nutrients. Given this early commitment, cardiomyocytes were traditionally considered transcriptionally stable cells fully committed to contractile function. However, growing evidence suggests that the maintenance of cardiac function in health and disease depends on transcriptional and epigenetic regulation. Several studies have revealed that the complex transcriptional alterations underlying cardiovascular disease (CVD) manifestations such as myocardial infarction and hypertrophy is mediated by cardiac retinoid X receptors (RXR) and their partners. RXRs are members of the nuclear receptor (NR) superfamily of ligand-activated transcription factors and drive essential biological processes such as ion handling, mitochondrial biogenesis, and glucose and lipid metabolism. RXRs are thus attractive molecular targets for the development of effective pharmacological strategies for CVD treatment and prevention. In this review, we summarize current knowledge of RXR partnership biology in cardiac homeostasis and disease, providing an up-to-date view of the molecular mechanisms and cellular pathways that sustain cardiomyocyte physiology.

Oxidative stress in cardiac hypertrophy: From molecular mechanisms to novel therapeutic targets

When faced with increased workload the heart undergoes remodelling, where it increases its muscle mass in an attempt to preserve normal function. This is referred to as cardiac hypertrophy and if sustained, can lead to impaired contractile function. Experimental evidence supports oxidative stress as a critical inducer of both genetic and acquired forms of cardiac hypertrophy, a finding which is reinforced by elevated levels of circulating oxidative stress markers in patients with cardiac hypertrophy. These observations formed the basis for using antioxidants as a therapeutic means to attenuate cardiac hypertrophy and improve clinical outcomes. However, the use of antioxidant therapies in the clinical setting has been associated with inconsistent results, despite antioxidants having been shown to exert protection in several animal models of cardiac hypertrophy. This has forced us to revaluate the mechanisms, both upstream and downstream of oxidative stress, where recent studies demonstrate that apart from conventional mediators of oxidative stress, metabolic disturbances, mitochondrial dysfunction and inflammation as well as dysregulated autophagy and protein homeostasis contribute to disease pathophysiology through mechanisms involving oxidative stress. Importantly, novel therapeutic targets have been identified to counteract oxidative stress and attenuate cardiac hypertrophy but more interestingly, the repurposing of drugs commonly used to treat metabolic disorders, hypertension, peripheral vascular disease, sleep disorders and arthritis have also been shown to improve cardiac function through suppression of oxidative stress. Here, we review the latest literature on these novel mechanisms and intervention strategies with the aim of better understanding the complexities of oxidative stress for more precise targeted therapeutic approaches to prevent cardiac hypertrophy.

Concurrent diabetes and heart failure: interplay and novel therapeutic approaches

Diabetes mellitus increases the risk of developing heart failure, and the co-existence of both diseases worsens cardiovascular outcomes, hospitalization and the progression of heart failure. Despite current advancements on therapeutic strategies to manage hyperglycemia, the likelihood of developing diabetes-induced heart failure is still significant, especially with the accelerating global prevalence of diabetes and an ageing population. This raises the likelihood of other contributing mechanisms beyond hyperglycemia in predisposing diabetic patients to cardiovascular disease risk. There has been considerable interest in understanding the alterations in cardiac structure and function in the diabetic patients, collectively termed as "diabetic cardiomyopathy". However, the factors that contribute to the development of diabetic cardiomyopathies is not fully understood. This review summarizes the main characteristics of diabetic cardiomyopathies, and the basic mechanisms that contribute to its occurrence. This includes perturbations in insulin resistance, fuel preference, reactive oxygen species generation, inflammation, cell death pathways, neurohormonal mechanisms, advanced glycated end-products accumulation, lipotoxicity, glucotoxicity, and posttranslational modifications in the heart of the diabetic. This review also discusses the impact of antihyperglycemic therapies on the development of heart failure, as well as how current heart failure therapies influence glycemic control in diabetic patients. We also highlight the current knowledge gaps in understanding how diabetes induces heart failure.