Insulin Causes [Ca 2+ ] i -Dependent and [Ca 2+ ] i -Independent Positive Inotropic Effects in Failing Human Myocardium

Direct and indirect effects of adiposity on markers of autonomic nervous system activity in older adults

Several cardiovascular disease (CVD) risk factors (e.g., hypertension, poor glycemic control) can affect and be affected by autonomic nervous system (ANS) activity. Since excess adiposity can influence CVD development through its effect on hypertension and diabetes mellitus, it is important to determine how adiposity and altered ANS activity are related. The present study employed structural equation modeling to investigate the relation between adiposity and ANS activity both directly and indirectly through biological variables typically associated with glycemic impairment and cardiac stress in older adults. Utilizing the Atherosclerosis Risk in Communities (ARIC) dataset, 1,145 non-smoking adults (74±4.8 yrs, 62.8% female) free from known CVD, hypertension, and diabetes and not currently taking beta-blockers were evaluated for fasting blood glucose (FBG), insulin, and HbA1c concentrations, waist circumference (WC), blood pressure (BP), and markers of ANS activity. WC was recorded just above the iliac crest and was used to reflect central adiposity. Resting 2-minute electrocardiograph recordings, pulse wave velocity, and ankle-brachial index data were used to assess the root mean square of successive differences in RR intervals (RMSSD) and the pre-ejection period (PEP), markers of parasympathetic and sympathetic activity, respectively. FBG, insulin, and HbA1c inferred a latent variable termed glycemic impairment (GI), whereas heart rate and diastolic BP inferred a latent variable termed cardiac stress (CS). The structural equation model fit was acceptable [root mean square error of approximation = 0.050 (90% CI = .036, .066), comparative fit index = .970, Tucker Lewis Index = 0.929], with adiposity having both significant direct (β = 0.208, p = 0.018) and indirect (β = -.217, p = .041) effects on PEP through GI. Adiposity displayed no significant direct effect on RMSSD. CS displayed a significant pathway (β = -0.524, p = 0.035) on RMSSD, but the indirect effect of WC on RMSSD through CS did not reach statistical significance (β = -0.094, p = 0.137). These results suggest that adiposity's relation to ANS activity is multifaceted, as increased central adiposity had opposing direct and indirect effects on markers of sympathetic activity in this population of older adults.

PI3K/Akt pathway mediates the positive inotropic effects of insulin in Langendorff-perfused rat hearts

Insulin exerts positive inotropic effects on cardiac muscle; however, the relationship between cardiac contractility and phosphoinositol-3-kinase/Akt (PI3K/Akt) activation remains unclear. We hypothesized that the positive inotropic effects of insulin are dose-dependent and mediated via the PI3K/Akt pathway in isolated normal rat hearts. The Institutional Animal Investigation Committee approved the use of hearts excised from rats under pentobarbital anesthesia. The hearts were perfused at a constant pressure using the Langendorff technique. After stabilization (baseline), the hearts were randomly divided into the following four insulin (Ins) groups: 1) Ins0 (0 IU/L), 2) Ins0.5 (0.5 IU/L), 3) Ins5 (5 IU/L), and 4) Ins50 (50 IU/L) (n = 8 in each group). To clarify the role of the PI3K/Akt pathway in insulin-dependent inotropic effects, we also treated the insulin groups with the PI3K inhibitor wortmannin (InsW): 5) InsW0 (0 IU/L), 6) InsW0.5 (0.5 IU/L), 7) InsW5 (5 IU/L), and 8) InsW50 (50 IU/L). Hearts were perfused with Krebs–Henseleit buffer solution with or without wortmannin for 10 min, followed by 20 min perfusion with the solution containing each concentration of insulin. The data were recorded as the maximum left ventricular derivative of pressure development (LV dP/dt max). Myocardial p-Akt levels were measured at 3 min, 5 min, and at the end of the perfusion. In the Ins groups, LV dP/dt max in Ins5 and Ins50 increased by 14% and 48%, respectively, 3 min after insulin perfusion compared with the baseline. Tachyphylaxis was observed after 10 min in the Ins5 and Ins50 treatment groups. Wortmannin partially inhibited the positive inotropic effect of insulin; although insulin enhanced p-Akt levels at all time points compared with the control group, this increase was suppressed in the presence of wortmannin. The positive inotropic effect of insulin is dose-dependent and consistent with Akt activation. This effect mediated by high doses of insulin on cardiac tissue was temporary and caused tachyphylaxis, potentially triggered by Akt overactivation, which leads beta 1 deactivation.

Cardioprotective Actions of Nitroxyl Donor Angeli's Salt are Preserved in the Diabetic Heart and Vasculature in the Face of Nitric Oxide Resistance

Background and Purpose

The risk of fatal cardiovascular events is increased in patients with type 2 diabetes mellitus (T2DM). A major contributor to poor prognosis is impaired nitric oxide (NO•) signalling at the level of tissue responsiveness, termed NO• resistance. This study aimed to determine if T2DM promotes NO• resistance in the heart and vasculature and whether tissue responsiveness to nitroxyl (HNO) is affected.

Experimental Approach

At 8 weeks of age, male Sprague–Dawley rats commenced a high‐fat diet. After 2 weeks, the rats received low‐dose streptozotocin (two intraperitoneal injections, 35 mg·kg⁻¹, over two consecutive days) and continued on the same diet. Twelve weeks later, isolated hearts were Langendorff‐perfused to assess responses to the NO• donor diethylamine NONOate (DEA/NO) and the HNO donor Angeli's salt. Isolated mesenteric arteries were utilised to measure vascular responsiveness to the NO• donors sodium nitroprusside (SNP) and DEA/NO, and the HNO donor Angeli's salt.

Key Results

Inotropic, lusitropic and coronary vasodilator responses to DEA/NO were impaired in T2DM hearts, whereas responses to Angeli's salt were preserved or enhanced. Vasorelaxation to Angeli's salt was augmented in T2DM mesenteric arteries, which were hyporesponsive to the relaxant effects of SNP and DEA/NO.

Conclusion and Implications

This is the first evidence that inotropic and lusitropic responses are preserved, and NO• resistance in the coronary and mesenteric vasculature is circumvented, by the HNO donor Angeli's salt in T2DM. These findings highlight the cardiovascular therapeutic potential of HNO donors, especially in emergencies such as acute ischaemia or heart failure.

Evaluation of high-dose insulin/euglycemia therapy for suspected β-blocker or calcium channel blocker overdose following guideline implementation

PURPOSE

High-dose insulin/euglycemia (HDIE) is targeted therapy for β-blocker and calcium channel blocker overdose. A guideline using concentrated insulin infusions (20 units/mL), aggressive monitoring, and supportive recommendations was implemented. We sought to evaluate safety before and after HDIE guideline implementation and describe the patient population, insulin doses, supplemental dextrose, vasopressor use, hospital and intensive care unit (ICU) lengths of stay, and mortality.

METHODS

Retrospective review was performed of patients receiving HDIE before and after guideline implementation at an academic medical center and community hospital from March 2011 through December 2019. Information on patient and overdose demographics, ingestion data, vital signs, interventions, adverse events, and disposition was collected. Data are presented descriptively with comparisons using Mann-Whitney U analysis and Fisher's exact tests.

RESULTS

During the study period, 27 patients were treated with HDIE, 10 before guideline implementation (37%; mean [SD] initial insulin dose, 0.49 [0.35] units/kg/h; mean [SD] maximum insulin dose, 2.25 [3.29] units/kg/h; median [interquartile range] duration, 10 [5.5-18.75] hours) and 17 after guideline implementation (63%; mean [SD] initial insulin dose, 1.01 [0.34] units/kg/h; mean [SD] maximum insulin dose, 2.99 [5.05] unit/kg/h; median [interquartile range] duration, 16 [11.5-37] hours). Hypoglycemia, hypokalemia, and volume overload occurred in 80% vs 29% (P = 0.018), 40% vs 53% (P = 0.69), and 50% vs 65% (P = 0.69) of patients in the preguideline vs postguideline group, respectively. Most patients received an initial insulin bolus (85%; mean [SD], 70.3 [21.8] units, 0.9 [0.26] units/kg) and vasopressor infusion (85%). More postguideline patients received a dextrose infusion with a concentration of 20% or higher (93% vs 50%, P = 0.015). There were no differences in cardiac arrest, in-hospital mortality, or hospital or ICU length of stay between the groups.

CONCLUSION

Hypoglycemia was reduced using an HDIE guideline and concentrated insulin.

Stress hyperglycemia, cardiac glucotoxicity, and critically ill patient outcomes current clinical and pathophysiological evidence

Stress hyperglycemia is a transient increase in blood glucose during acute physiological stress in the absence of glucose homeostasis dysfunction. Its's presence has been described in critically ill patients who are subject to many physiological insults. In this regard, hyperglycemia and impaired glucose tolerance are also frequent in patients who are admitted to the intensive care unit for heart failure and cardiogenic shock. The hyperglycemia observed at the beginning of these cardiac disorders appears to be related to a variety of stress mechanisms. The release of major stress and steroid hormones, catecholamine overload, and glucagon all participate in generating a state of insulin resistance with increased hepatic glucose output and glycogen breakdown. In fact, the observed pathophysiological response, which appears to regulate a stress situation, is harmful because it induces mitochondrial impairment, oxidative stress-related injury to cells, endothelial damage, and dysfunction of several cellular channels. Paradigms are now being challenged by growing evidence of a phenomenon called glucotoxicity, providing an explanation for the benefits of lowering glucose levels with insulin therapy in these patients. In the present review, the authors present the data published on cardiac glucotoxicity and discuss the benefits of lowering plasma glucose to improve heart function and to positively affect the course of critical illness.

Titin and CK2α are New Intracellular Targets in Acute Insulin Application-Associated Benefits on Electrophysiological Parameters of Left Ventricular Cardiomyocytes From Insulin-Resistant Metabolic Syndrome Rats

BACKGROUND

Previous studies have demonstrated that a high-carbohydrate intake could induce metabolic syndrome (MetS) in male rats with marked cardiac functional abnormalities. In addition, studies mentioned some benefits of insulin application on these complications, but there are considerable disagreements among their findings. Therefore, we aimed to extend our knowledge on the in-vitro influence of insulin on left ventricular dysfunction and also in the isolated cardiomyocytes from MetS rats.

RESULTS

At the organ function level, an acute insulin application (100-nM) provided an important beneficial effect on the left ventricular developed pressure in MetS rats. Furthermore, to treat the freshly isolated cardiomyocytes from MetS rats with insulin provided marked recoveries in elevated resting intracellular Ca²⁺-level, as well as significant prevention of prolonged action potential through an augmentation in depressed K⁺-channel currents. Insulin also normalized the cellular levels of increased ROS and phosphorylation of PKCα, together with normalizations of apoptotic markers in MetS cardiomyocytes through the insulin-mediated regulation of phospho-Akt. Since not only elevated PKCα-activity but also reductions in phospho-Akt are key modulators of titin-based cardiomyocyte stiffening in hyperglycemia, insulin treatment of the cardiomyocytes prevented the activation of titin via the above pathways. Furthermore, CK2α-activation and NOS-phosphorylation could be prevented with insulin treatment. Mechanistically, we found that impaired insulin signaling and elevated PKCα and CK2α activities, as well as depressed Akt phosphorylation, are key modulators of titin-based cardiomyocyte stiffening in MetS rats.

CONCLUSION

We propose that restoring normal kinase activities and also increases in phospho-Akt by insulin can contribute marked recoveries in MetS heart function, indicating a promising approach to modulate titin-associated factors in heart dysfunction associated with type-2 diabetes mellitus. Graphical Abstract.

The Crashing Toxicology Patient

This article examines, using an organ-systems based approach, rapid diagnosis, resuscitation, and critical care management of the crashing poisoned patient in the emergency department. The topics discussed in this article include seizures and status epilepticus, respiratory failure, cardiovascular collapse and mechanical circulatory support, antidotes and drug-specific therapies, acute liver failure, and extracorporeal toxin removal.

Caloric restriction in heart failure: A systematic review

BACKGROUND AND AIMS

Nutrition exerts a determinant role in maintaining cardiac function, regulating insulin and mitochondrial efficiency, that are essential to support energy production for contractility. In patients with heart failure (HF), myocardial tissue efficiency is reduced because of decreased mitochondrial oxidative capacity. In HF conditions, cardiomyocytes shift toward glucose and a reduction in fatty acid utilization. Calorie restriction induces weight loss in obese patients and can be beneficial in some HF patients, although this has generated some controversy. This study aims to evaluate the impact of the CR diet on myocardial efficiency in HF patients.

METHODS

On Pubmed and Embase, articles related to the keywords: "chronic heart failure" with "diet," "nutrition," "insulin resistance," and "caloric restriction" have been searched, Studies, including exercise or food supplementation, were excluded.

RESULTS

The retrieved articles showed that weight loss, through the activation of insulin and various kinase pathways, regulates the efficiency of myocardial tissue. In contrast, insulin resistance represents a strong cardiovascular risk factor that reduces myocardial function.

CONCLUSION

CR diet represents the first therapy in overweight HF patients, both with preserved ejection fraction (HFpEF) and with reduced ejection fraction (HFrHF) because reducing body fat, the myocardial function increased. Insulin activity is the critical hormone that regulates mitochondrial function and cardiac efficiency. However, a severely restricted diet may represent a severe risk factor correlated with all-cause mortality, particularly in underweight HF patients. Long-term studies conducted on large populations are necessary to evaluate the effects of CR on myocardial function in HF patients.

Hesperidin ameliorates signs of the metabolic syndrome and cardiac dysfunction via IRS/Akt/GLUT4 signaling pathway in a rat model of diet-induced metabolic syndrome

BACKGROUND

Hesperidin has been reported to have biological activities such as antihypertensive, hypoglycemic, and antioxidant effects. This study investigated whether hesperidin could improve signs of the metabolic syndrome and cardiac function in a high-fat diet (HFD) induced metabolic syndrome (MS) in rats.

METHODS

Male Sprague-Dawley rats were fed HFD and 15% fructose for 16 weeks and treated with hesperidin (15 or 30 mg/kg, based on signs of MS from a preliminary study) or metformin, a positive control agent, (100 mg/kg) for the final four weeks. Cardiac function, blood pressure, fasting blood glucose, oral glucose tolerance, serum insulin, and lipid profiles were measured. Histomorphometrics of left ventricles, epidydimal fat pads and liver were evaluated. Expressions of phosphorylate insulin receptor substrate1(p-IRS1), p-Akt and GLUT4 in cardiac tissue were determined.

RESULTS

Hesperidin and metformin attenuated MS in HFD rats (p < 0.05). The accumulation of visceral fat pads and fatty liver associated with increases in liver lipid contents and liver enzymes were found in MS rats that were alleviated in hesperidin or metformin-treated groups (p < 0.05). Hesperidin and metformin improved cardiac dysfunction and hypertrophy observed in MS rats (p < 0.05). Restoration of the insulin signaling pathway, IRS/Akt/GLUT4 protein expression, was demonstrated in hesperidin and metformin-treated groups (p < 0.05). Hesperidin (30 mg/kg) was more effective than the lower dose.

CONCLUSION

Hesperidin was effective in reducing signs of MS and alterations of LV hypertrophy and function. These beneficial effects on the heart were associated with the restoration of the cardiac insulin signaling pathway in MS rats.

High-Dose Insulin for Toxin Induced Cardiogenic Shock: Experience at a New High and Overview of the Evidence

BACKGROUND

High-dose insulin therapy is an effective treatment for cardiogenic shock caused by the overdose of particular medications. Other treatment options are usually of limited benefit. Consensus suggests that early initiation improves efficacy. No ceiling effect has been established at doses in the general range of 0.5-10 units/kg/hour.

CASE REPORT

A 79-year-old man presented in cardiogenic shock after an intentional overdose of numerous cardioactive medications 10 days after experiencing myocardial infarction. A high-dose insulin infusion was commenced. This was titrated up to a maximum of 20 units/kg/hour (1600 units/hour) and sustained for 32 h (61,334 units total). Minimal adverse events were seen despite this exceptional infusion rate (3 episodes of hypoglycemia and 2 episodes of hypokalemia). Concurrent catecholamine support was used, and cardiovascular function was maintained until all support was withdrawn 5 days after admission. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Emergency physicians are pivotal to the successful initiation/up-titration of high-dose insulin therapy. They must balance the potential for treatment failure with other treatment options, mitigate against adverse events in the initial phase of therapy, and coordinate care between other hospital specialties. This case shows that the relative safety and efficacy was extended to an infusion rate of 20 units/kg/hour, the highest recorded in the published literature. This information may help guide treatment of similar cases in the future.

Pharmacological inhibition of guanosine triphosphate cyclohydrolase1 elevates tyrosine phosphorylation of caveolin1 and cellular senescence

The role of 2,4-diamino-6-hydroxypyrimidine (DAHP), on cellular-senescence remains unclear as differential effects of DAHP have been reported in cardiovascular and cerebrovascular systems. We investigated the effect of pharmacologically-induced guanosine-triphosphate-cyclohydrolase1 (GTPCH1)-inhibition, through DAHP, on cellular-senescence in experimentally-induced diabetic and non-diabetic Wistar rats. Cellular-senescence was evaluated through senescence-associated events, namely, cell-cycle-arrest of peripheral blood mononuclear cells (PBMNCs); myocardial DNA fragmentation, total antioxidant capacity (TAC), telomerase-activity, nicotinamide adenine dinucleotide (NAD⁺)-content and tyrosine14-phosphorylation of caveolin1 (pY14) in similarly-aged, pubertal Wistar rats with streptozotocin (STZ) and/or DAHP. Oxidative stress (OS) indices such as myocardial biopterin concentrations (tetrahydrobiopterin-BH₄ and dihydrobiopterin-BH₂) and plasma total nitrite and nitrate (NOx) were determined. DAHP, per se, exhibited distinct senescence; in addition, in STZ+DAHP (the cardiomyopathy model), there was a marked accumulation of cells in G0G1 phase, as evidenced through flow-cytometry analysis, as-well-as fragmented DNA, than the respective controls suggesting the DAHP-mediated onset of senescence in circulating cells and the myocardium, with or without STZ. Concentrations of BH4 and BH2, and NOx were impaired in STZ and/or DAHP, indicating elevated OS in the treatment groups. In the independent treatment groups or the combination treatment, typical senescence indicators including myocardial telomerase-activity, NAD⁺-content and TAC were significantly reduced, while there was a marked elevation in the concentrations of pY14 as compared to the respective controls, reinforcing the occurrence of senescence in PBMNCs and the myocardium. We postulate that DAHP promotes early onset of cellular-senescence, potentially through OS-mediated cellular events in diabetic or non-diabetic models.

Pretreatment with glucose-insulin-potassium improves ventricular performances after coronary artery bypass surgery: a randomized controlled trial

Heart failure is the main cause of poor outcome following open heart surgery and experimental studies have demonstrated that glucose–insulin–potassium (GIK) infusion exerts cardioprotective effects by reducing myocardial ischemia–reperfusion injuries. This randomized controlled trial was designed to assess the effects of GIK on left ventricular function in moderate-to-high risk patients undergoing on-pump isolated coronary artery bypass surgery (CABGS), or combined with aortic valve replacement. The primary outcomes were the effects of GIK on two- and three-dimensional left ventricular ejection fraction (2D and 3D-LVEF), and on transmitral flow propagation velocity (Vp), that occurred between the pre- and post-CPB periods. GIK administration was associated with favorable interaction effects (p < 0.001) on 2D-LVEF, 3D-LVEF and Vp changes over the study periods. In GIK pretreated patients (N = 54), 2-D and 3D-LVEF and Vp increased slightly during surgery (mean difference [MD] + 3.5%, 95% confidence interval [95% CI] − 0.2 to 7.1%, MD + 4.0%, 95% CI 0.6–7.4%, and MD + 22.2%, 95% CI 16.0–28.4%, respectively). In contrast, in the Placebo group (N = 46), 2D-and 3D-LVEF, as well as Vp all decreased after CPB (MD − 7.5% [− 11.6 to − 3.4%], MD − 12.0% [− 15.2 to − 8.8%] and MD − 21.3% [− 25.7 to − 16.9%], respectively). In conclusion, the administration of GIK resulted in better preservation of systolic and diastolic ventricular function in the early period following weaning from CPB.

Caloric restriction attenuates aging-induced cardiac insulin resistance in male Wistar rats through activation of PI3K/Akt pathway

BACKGROUND AND AIM

Caloric restriction (CR) improves insulin sensitivity and is one of the dietetic strategies most commonly used to enlarge life and to prevent aging-induced cardiovascular alterations. The aim of this study was to analyze the possible beneficial effects of caloric restriction (CR) preventing the aging-induced insulin resistance in the heart of male Wistar rats.

METHODS AND RESULTS

Three experimental groups were used: 3 months old rats (3m), 24 months old rats (24m) and 24 months old rats subjected to 20% CR during their three last months of life (24m-CR). After sacrifice hearts were mounted in a perfusion system (Langendorff) and heart function in basal conditions and in response to accumulative doses of insulin (10^-9-10^-7 M), in the presence or absence of Wortmannin (10^-6 M), was recorded. CR did not attenuate the aging-induced decrease in coronary artery vasodilation in response to insulin administration, but it prevented the aging-induced downregulation of cardiac contractility (dp/dt) through activation of the PI3K/Akt intracellular pathway. Insulin stimulated in a greater extent the PI3K/Akt pathway vs the activation of the MAPK pathway and increased the protein expression of IR, GLUT-4 and eNOS in the hearts of 3m and 24m-CR rats, but not in the hearts of 24m rats. Furthermore, CR prevented the aging induced increase in endothelin-1 protein expression in myocardial tissue.

CONCLUSION

In conclusion CR partially improves cardiac insulin sensitivity and prevents the aging induced decrease in myocardial contractility in response to insulin administration through activation of PI3K/Akt pathway.

Pharmacological and mechanical management of calcium channel blocker toxicity

Cardiovascular instability associated with calcium channel blocker toxicity comprises a small percentage of overdose presentations, yet they are associated with a high mortality rate. We detail the management of a 64-year-old man who took an intentional overdose of 840 mg nimodipine. We include the treatment he received and highlight the scarcity of evidence behind the use of gastric decontamination, calcium, glucagon, intravenous lipid emulsion, high-dose insulin therapy, sodium bicarbonate, vasopressors and methylene blue in calcium channel blocker toxicity. Additionally, the article explores the use of electrical pacing and venoarterial extracorporeal membrane oxygenation (VA-ECMO). Following successful weaning of VA-ECMO, the patient was successfully extubated but remained neurologically impaired due to hypoxic-ischaemic brain injury, critical care polyneuropathy and renal failure requiring dialysis. He has cerebral performance category 3; he has mild cognitive impairment but able to perform some activities of daily living independently and communicate his thoughts and needs. He requires no respiratory or cardiovascular support.

β-Blocker and Calcium Channel Blocker Poisoning: High-Dose Insulin/Glucose Therapy

Overdoses of β-blockers and calcium channel blockers can produce significant morbidity and mortality, and conventional therapies often do not work as treatments for these poisonings. High-dose insulin/glucose therapy has been successful in reversing the cardiotoxic effects of these drugs in cases where the standard therapies have failed, and it appears to be relatively safe. Many successes have been well documented, but the clinical experience consists of case reports, the mechanisms of action are not completely understood, and guidelines for use of the therapy are empirically derived and not standardized. Regardless of these limitations, high-dose insulin/glucose therapy can be effective, it is often recommended by clinical toxicologists and poison control centers, and critical care nurses should be familiar with when and how the therapy is used.

Study of insulin vascular sensitivity in aortic rings and endothelial cells from aged rats subjected to caloric restriction: Role of perivascular adipose tissue

The prevalence of metabolic syndrome is dramatically increasing among elderly population. Metabolic syndrome in aged individuals is associated with hyperinsulinemia and insulin resistance both in metabolic tissues and in the cardiovascular system, with this fact being associated with the cardiometabolic alterations associated to this condition. Caloric restriction (CR) improves insulin sensitivity and is one of the dietetic strategies most commonly used to enlarge life and to prevent aging induced cardiovascular alterations. The aim of this study was to analyze the possible beneficial effects of CR in aging-induced vascular insulin resistance both in aortic rings and in primary culture of endothelial cells. In addition, the inflammatory profile of perivascular adipose tissue (PVAT) and its possible role in the impairment of vascular insulin sensitivity associated with aging was also assessed. Three experimental groups of male Wistar rats were used: 3 (3m), 24 (24m) fed ad libitum and 24months old rats subjected to 20% CR during their three last months of life (24m-CR). Aorta rings surrounded or not by PVAT were mounted in an organ bath and precontracted with phenylephrine (10^-7.5M). Changes in isometric tension were recorded in response to cumulative insulin concentrations (10^-8-10^-5.5M) in the presence or absence of L-NAME (10^-4M). Aortic rings and primary aortic endothelial cells were incubated in presence/absence of insulin (10^-7M) and the activation of the PI3K/Akt and MAPK pathways as well as nitrite and nitrates concentrations and the mRNA levels of eNOS, insulin receptor, and GLUT-4 were assessed. CR prevented the aging-induced decrease in the vasodilator response to insulin and the aging-induced increase in the vasoconstrictor response to high insulin concentrations. Changes between 24m and 24m-CR aorta rings were abolished in the presence of L-NAME. CR induced-improvement in insulin vascular sensitivity was related with activation of the PI3K/Akt both in aortic rings and in aortic endothelial cells in response to insulin. CR attenuated the overexpression of iNOS, TNF-α and IL-1β in the PVAT of aged rats although aortic rings surrounded by PVAT from 24m rats showed and increased vasorelaxation in response to insulin compared to aortic rings from 3m and 24m-CR rats. In conclusion, a moderate protocol of CR improves insulin vascular sensitivity and prevents the aging induced overexpression of pro-inflammatory cytokines in PVAT.

New Antihyperglycemic Drugs and Heart Failure: Synopsis of Basic and Clinical Data

The assessment of the cardiovascular safety profile of any newly developed antihyperglycemic drug is mandatory before registration, as a meta-analysis raised alarm describing a significant increase in myocardial infarction with the thiazolidinedione rosiglitazone. The first results from completed cardiovascular outcome trials are already available: TECOS, SAVOR-TIMI, and EXAMINE investigated dipeptidyl peptidase 4 (DPP-4) inhibitors, ELIXA, LEADER, and SUSTAIN-6 investigated glucagon-like peptide 1 (GLP-1) receptor agonists, and EMPA-REG OUTCOME and CANVAS investigated sodium-dependent glucose transporter 2 (SGLT-2) inhibitors. LEADER, SUSTAIN-6, EMPA-REG OUTCOME, and CANVAS showed potential beneficial results, while the SAVOR-TIMI trial had an increased rate of hospitalization for heart failure. Meanwhile, the same drugs are investigated in preclinical experiments mainly using various animal models, which aim to find interactions and elucidate the underlying downstream mechanisms between the antihyperglycemic drugs and the cardiovascular system. Yet the direct link for observed effects, especially for DPP-4 and SGLT-2 inhibitors, is still unknown. Further inquiry into these mechanisms is crucial for the interpretation of the clinical trials' outcome and, vice versa, the clinical trials provide hints for an involvement of the cardiovascular system. The synopsis of preclinical and clinical data is essential for a detailed understanding of benefits and risks of new antihyperglycemic drugs.

Review of management in cardiotoxic overdose and efficacy of delayed intralipid use

We present the case of a 51-year-old woman admitted to our intensive care unit following an intentional overdose of a calcium channel antagonist and a beta blocker. The resultant hypotension was reversed with glucagon, noradrenaline, calcium and high-dose insulin. Despite these interventions, she remained vasoplegic and received a delayed, standard dose of intralipid. Subsequently, the vasoplegia resolved rapidly, and the vasopressor was stopped. Here, we review the management of overdose of calcium channel and beta-adrenergic receptor blockers, concentrating on the pharmacology of lipid emulsion therapy. There remain some unanswered questions about lipid emulsion therapy: treatment with lipid therapy is usually advocated as soon as possible; this case report suggests that it remains efficacious even if its administration were delayed.

Calcium channel antagonist and beta-blocker overdose: antidotes and adjunct therapies

Management of cardiovascular instability resulting from calcium channel antagonist (CCB) or beta-adrenergic receptor antagonist (BB) poisoning follows similar principles. Significant myocardial depression, bradycardia and hypotension result in both cases. CCBs can also produce vasodilatory shock. Additionally, CCBs, such as verapamil and diltiazem, are commonly ingested in sustained-release formulations. This can also be the case for some BBs. Peak toxicity can be delayed by several hours. Provision of early gastrointestinal decontamination with activated charcoal and whole-bowel irrigation might mitigate this. Treatment of shock requires a multimodal approach to inotropic therapy that can be guided by echocardiographic or invasive haemodynamic assessment of myocardial function. High-dose insulin euglycaemia is commonly recommended as a first-line treatment in these poisonings, to improve myocardial contractility, and should be instituted early when myocardial dysfunction is suspected. Catecholamine infusions are complementary to this therapy for both inotropic and chronotropic support. Catecholamine vasopressors and vasopressin are used in the treatment of vasodilatory shock. Optimizing serum calcium concentration can confer some benefit to improving myocardial function and vascular tone after CCB poisoning. High-dose glucagon infusions have provided moderate chronotropic and inotropic benefits in BB poisoning. Phosphodiesterase inhibitors and levosimendan have positive inotropic effects but also produce peripheral vasodilation, which can limit blood pressure improvement. In cases of severe cardiogenic shock and/or cardiac arrest post-poisoning, extracorporeal cardiac assist devices have resulted in successful recovery. Other treatments used in refractory hypotension include intravenous lipid emulsion for lipophilic CCB and BB poisoning and methylene blue for refractory vasodilatory shock.

Use of insulin to decrease septic shock-induced myocardial depression in a porcine model

Insulin is known to attenuate septic shock-induced myocardial depression. Possible mechanisms include an anti-inflammatory or inotropic effect of insulin. The objective of this study was to determine whether the mechanism of action of insulin in attenuating septic shock-induced myocardial depression is through an immunomodulatory effect. Fourteen pigs were assigned to one of two groups. Both groups received a 4-h infusion of lipopolysaccharide endotoxin from Escherichia coli 0111:B4. Group 2 additionally received insulin at 1.5 U/kg/h with infusions of D50 normal saline and KCl to maintain normal serum glucose and potassium levels. Cardiac function was measured with shortening fraction using transthoracic echocardiogram. Plasma TNF-α, IL-1β, and IL-6 levels were obtained every 30 min. Postmortem cytokine analysis and histomorphology were performed on the heart tissue. Although insulin attenuated septic shock-induced myocardial depression, this was not due to an anti-inflammatory effect and, therefore, likely resulted from an inotropic effect of insulin.

High-dose insulin and intravenous lipid emulsion therapy for cardiogenic shock induced by intentional calcium-channel blocker and Beta-blocker overdose: a case series

BACKGROUND

Recently, high-dose insulin (HDI) and intravenous lipid emulsion (ILE) have emerged as treatment options for severe toxicity from calcium-channel blocker (CCB) and beta blocker (BB).

OBJECTIVE

Our aim was to describe the use and effectiveness of HDI and ILE for the treatment of CCB and BB overdose.

CASE REPORTS

We describe 2 patients presenting to the emergency department after intentional ingestions of CCBs and BBs. A 35-year-old man presented in pulseless electrical activity after ingesting amlodopine, verapamil, and metoprolol. A 59-year-old man presented with cardiogenic shock (CS) after ingesting amlodopine, simvastatin, lisinopril, and metformin. Both patients were initially treated with glucagon, calcium, and vasopressors. Shortly after arrival, HDI (1 unit/kg × 1; 1 unit/kg/h infusion) and ILE 20% (1.5 mL/kg × 1; 0.25 mL/kg/min × 60 min) were initiated. This led to hemodynamic improvement and resolution of shock. At the time of hospital discharge, both patients had achieved full neurologic recovery.

CONCLUSIONS

HDI effectively reverses CS induced by CCBs and BBs due to its inotropic effects, uptake of glucose into cardiac muscle, and peripheral vasodilatation. ILE is theorized to sequester agents dependent on lipid solubility from the plasma, preventing further toxicity. To our knowledge, these are the first two successful cases reported using the combination of HDI and ILE for reversing CS induced by intentional ingestions of CCBs and BBs.

Pathology, pathophysiology, and treatment strategies of endocrine disorders and their cardiac complications

The cardiovascular system is affected by a multitude of endocrine disorders, including dysfunction of the thyroid, calcium, glucocorticoids, insulin/glucose, and growth hormone axes. Since most of these changes in the cardiovascular system are reversible when treated, early diagnosis is important, as if left untreated, they may become fatal. This review focuses on the pathophysiology, clinical presentation, pathology, and treatment of patients with these endocrine diseases who present with a variety of cardiovascular manifestations. Neuroendocrine tumors presenting with the carcinoid syndrome and their cardiovascular manifestations are also discussed.

The effect of carvedilol on blood glucose levels in normal albino rats

BACKGROUND

Carvedilol is a commonly used drug in hypertension, congestive heart failure in diabetics. It has moderate calcium channel blocking property in addition to α1 and non selective β antagonistic activity. Though some studies bring forth the beneficial effects of Carvedilol in cardiovascular comorbidities in diabetes, there is no consensus on its effects on glycaemic levels.

AIMS

To evaluate the effect of oral Carvedilol administration for 5 days on blood glucose levels in normal albino rats through Oral Glucose Tolerance Test.

MATERIAL AND METHODS

Twelve adult albino rats of either sex weighing between 150 - 200 g were selected from central animal facility and randomly divided into 2 groups - Control [Distilled water (1ml/rat orally)] and Test (0.8mg/kg body weight orally) and the respective drugs were administered over 5 days. Following overnight fasting, on the fifth day 1 hour after the last dose of the respective drug, OGTT was performed. The CBG (Capillary Blood Glucose) levels were measured at 0 min, glucose (2g/kg body weight) dissolved in water was administered to all the rats orally. The blood sample from tail vein (obtained by tail snipping) at 60 and 150 minutes were analysed for CBG levels using a standardized glucometer.

STATISTICAL ANALYSIS

Data was presented as Mean ± SEM. One way ANOVA, independent samples t-test, non-parametric tests, percentages and cross tabs were used in the analysis of data within the same group and between different groups when required.

RESULTS

Carvedilol group showed higher CBG levels at all time intervals of OGTT as compared to the Control group i.e., 0, 60 and 150 minutes, the highest being (103.8±5.029 )mg/dl at 60 minutes and was statistically significant. Carvedilol group however showed lesser inter-interval variation compared to the Control group at the same time intervals respectively but was statistically insignificant.

CONCLUSIONS

Carvedilol has hyperglycaemic potential when given orally for 5 days in normal albino rats. Though it may be beneficial in diabetics for various comorbid conditions, the glycaemic control may worsen during its use in subjects with prediabetes, diabetes, high risk diabetes.

High-fat feeding-induced hyperinsulinemia increases cardiac glucose uptake and mitochondrial function despite peripheral insulin resistance

In obesity, reduced cardiac glucose uptake and mitochondrial abnormalities are putative causes of cardiac dysfunction. However, high-fat diet (HFD) does not consistently induce cardiac insulin resistance and mitochondrial damage, and recent studies suggest HFD may be cardioprotective. To determine cardiac responses to HFD, we investigated cardiac function, glucose uptake, and mitochondrial respiration in young (3-month-old) and middle-aged (MA) (12-month-old) male Ldlr(-/-) mice fed chow or 3 months HFD to induce obesity, systemic insulin resistance, and hyperinsulinemia. In MA Ldlr(-/-) mice, HFD induced accelerated atherosclerosis and nonalcoholic steatohepatitis, common complications of human obesity. Surprisingly, HFD-fed mice demonstrated increased cardiac glucose uptake, which was most prominent in MA mice, in the absence of cardiac contractile dysfunction or hypertrophy. Moreover, hearts of HFD-fed mice had enhanced mitochondrial oxidation of palmitoyl carnitine, glutamate, and succinate and greater basal insulin signaling compared with those of chow-fed mice, suggesting cardiac insulin sensitivity was maintained, despite systemic insulin resistance. Streptozotocin-induced ablation of insulin production markedly reduced cardiac glucose uptake and mitochondrial dysfunction in HFD-fed, but not in chow-fed, mice. Insulin injection reversed these effects, suggesting that insulin may protect cardiac mitochondria during HFD. These results have implications for cardiac metabolism and preservation of mitochondrial function in obesity.

Insulin/glucose infusion successfully resuscitates bupivacaine-induced sudden-onset circulatory collapse in dogs

PURPOSE

In previous studies, insulin reversed the cardiac toxicity gradually induced by a continuous infusion of bupivacaine. In this randomized controlled study, we intended to simulate a more relevant clinical situation by injecting bupivacaine rapidly as a bolus to induce sudden-onset circulatory collapse in dogs. We then evaluated the insulin effect.

METHODS

Bupivacaine (10 mg.kg(-1) iv) was rapidly administered intravenously to 12 dogs. At the onset of circulatory collapse (defined as a mean arterial pressure [MAP] of 30 mmHg), external chest compression was initiated. Insulin (2 U.kg(-1) iv) was given to the insulin-glucose (IG) group (n = 6) and the same volume of 0.9% saline was given to the control (C) group (n = 6). The primary outcome was successful resuscitation defined as both MAP ≥ 60 mmHg and sinus rhythm on an electrocardiogram that lasted ≥ 60 sec. Hemodynamic and blood variables were measured, including cardiac output and electrocardiogram intervals.

RESULTS

All IG dogs were successfully resuscitated within 15 (3) min, whereas none of the control dogs were resuscitated (P = 0.002). After circulatory collapse, the average MAP was higher in group IG than in group C (P = 0.006).

CONCLUSION

Insulin effectively reversed the sudden-onset circulatory collapse in dogs caused by an intravenous bolus injection of bupivacaine.

JTV519 (K201) reduces sarcoplasmic reticulum Ca²⁺ leak and improves diastolic function in vitro in murine and human non-failing myocardium

BACKGROUND AND PURPOSE

Ca²⁺ leak from the sarcoplasmic reticulum (SR) via ryanodine receptors (RyR2s) contributes to cardiomyocyte dysfunction. RyR2 Ca²⁺ leak has been related to RyR2 phosphorylation. In these conditions, JTV519 (K201), a 1,4-benzothiazepine derivative and multi-channel blocker, stabilizes RyR2s and decrease SR Ca²⁺ leak. We investigated whether JTV519 stabilizes RyR2s without increasing RyR2 phosphorylation in mice and in non-failing human myocardium and explored underlying mechanisms.

EXPERIMENTAL APPROACH

SR Ca²⁺ leak was induced by ouabain in murine cardiomyocytes. [Ca²⁺]-transients, SR Ca²⁺ load and RyR2-mediated Ca²⁺ leak (sparks/waves) were quantified, with or without JTV519 (1 µmol·L⁻¹). Contribution of Ca²⁺ -/calmodulin-dependent kinase II (CaMKII) was assessed by KN-93 and Western blot (RyR2-Ser(2814) phosphorylation). Effects of JTV519 on contractile force were investigated in non-failing human ventricular trabeculae.

KEY RESULTS

Ouabain increased systolic and diastolic cytosolic [Ca²⁺](i) , SR [Ca²⁺], and SR Ca²⁺ leak (Ca²⁺ spark (SparkF) and Ca²⁺ wave frequency), independently of CaMKII and RyR-Ser(2814) phosphorylation. JTV519 decreased SparkF but also SR Ca²⁺ load. At matched SR [Ca²⁺], Ca²⁺ leak was significantly reduced by JTV519, but it had no effect on fractional Ca²⁺ release or Ca²⁺ wave propagation velocity. In human muscle, JTV519 was negatively inotropic at baseline but significantly enhanced ouabain-induced force and reduced its deleterious effects on diastolic function.

CONCLUSIONS AND IMPLICATIONS

JTV519 was effective in reducing SR Ca²⁺ leak by specifically regulating RyR2 opening at diastolic [Ca²⁺](i) in the absence of increased RyR2 phosphorylation at Ser(2814) , extending the potential use of JTV519 to conditions of acute cellular Ca²⁺ overload.

Cardiotoxic overdose treated with intravenous fat emulsion and high-dose insulin in the setting of hypertrophic cardiomyopathy

High-dose insulin (HDI) and intravenous fat emulsion (IFE) are used in overdoses, although rarely combined. To our knowledge, IFE therapy has not been reported in overdoses of diltiazem, metoprolol and amiodarone. We report a severe overdose of these drugs treated with HDI and IFE in a patient with hypertrophic cardiomyopathy (HCM). We also discuss the potential clinical implications of the inotropic effects of HDI in the setting of HCM and the use and efficacy of IFE in this overdose.

Endocrine changes in brain death and transplantation

Following brain death (BD) many hormonal changes occur. These include an increase and then a fall in the levels of circulating catecholamines, reduced levels of anti-diuretic hormone and cortisol as well as alterations in the hypothalamic-pituitary thyroid axis consistent with the non-thyroidal illness syndrome. In an era when the numbers of potential recipients listed for transplantation are greater than the number of donors, with an increasing donor age, a detailed knowledge of the endocrine changes and pathophysiological consequences of these is essential to optimise the management of the brain-stem dead organ donor. There still remains significant debate as to whether hormone replacement therapy to correct the observed changes is beneficial.

Insulin and the heart

The main role of insulin in the heart under physiological conditions is obviously the regulation of substrate utilization. Indeed, insulin promotes glucose uptake and its utilization via glycolysis. Insulin, promoting glucose as the main cardiac energy substrate, reduces myocardial O(2) consumption and increases cardiac efficiency. Moreover, insulin seems to augment cardiomyocyte contraction, while it affects favorably myocardial relaxation, increases ribosomal biogenesis and protein synthesis, stimulates vascular endothelial growth factor (VEGF) and thereby angiogenesis, suppresses apoptosis, promotes cell survival and finally ameliorates both myocardial microcirculation and coronary artery resistance, leading to increased blood perfusion of myocardium. Thus, insulin acts directly on heart muscle, and this action is mediated principally through PKB/Akt signal pathway. Under pathological conditions, such as type 2 diabetes, myocardial ischaemia, and cardiac hypertrophy, insulin signal transduction pathways and action are clearly modified. In this review we summarize the evidence that the heart is an important target of insulin action and that elimination of these actions is important in disease states.

Effects of high-dose insulin infusion on left ventricular function in normal subjects

Background. Only a few studies have reported on the effect of high-dose insulin (HDI) infusion on cardiac function in healthy volunteers. Methods. We studied ten healthy volunteers with low-dose dobutamine (LDD, 10 mug/kg/min) echo-cardio-graphy and HDI echocardiography (insulin administration for one hour) by volume and Doppler analysis. Results. During LDD, cardiac output increased from 5.7+/-1.3 l/min to 9.0+/-2.1 l/min (p<0.001) and during HDI from 5.5+/-1.2 l/min to 6.2+/-1.1 l/min (p=0.048). Increase was not only due to increase in frequency, which was only present in the LDD study, but also due to increase in stroke volume (from 82+/-15 ml to 110+/-23 ml, p<0.001 during LDD and from 82+/-16 ml to 93+/-24 ml, p=0.014 during HDI). The increase in stroke volume was the result of a decrease in end-systolic volume with an unchanged end-diastolic volume. Conclusion. High-dose insulin infusion results in increased cardiac output by improving systolic myocardial function. (Neth Heart J 2010;18:183-9.).

Insulin resistance: pathophysiology and rationale for treatment

After binding to its receptor and activating the β-subunit, insulin is faced with two divergent pathways: one is phosphatidylinositol 3-kinase (PI 3-K) dependent, while another is dependent upon activation of mitogen-activated protein kinase (MAP-K). The former is absolutely necessary for mediating most metabolic and antiapoptotic effects; the latter is linked to nonmetabolic, proliferative and mitogenic effects. In obese patients, especially with type 2 diabetes mellitus (DM2), only the PI 3-K, but not the MAP-K, is resistant to insulin stimulation: hence insulin resistance is better defined as metabolic insulin resistance. The resulting 'compensatory hyperinsulinemia' is an unsuccessful attempt to overcome the inhibition of the metabolic pathway at the price of unopposed stimulation of the MAP-K pathway, and the administration of exogenous insulin might worsen the metabolic dysfunction. As the preferential activation of the MAP-K pathway in insulin-resistant patients has atherogenic and mitogenic properties, this leads to atherosclerosis and cancer. Metformin may carry out direct protective action on human β cells, inasmuch as it improves both primary and secondary endpoints through selective inhibition of fatty acyl oxidation.

Functional effects of glucose transporters in human ventricular myocardium

AIMS

Insulin-dependent positive inotropic effects (PIE) are partially Ca(2+) independent. This mechanism is potentially glucose dependent. In contrast to most animal species, human myocardium expresses high levels of sodium-glucose-transporter-1 (SGLT-1) mRNA besides the common glucose-transporters-1 and -4 (GLUT1, GLUT4).

METHODS AND RESULTS

We used ventricular myocardium from 61 end-stage failing human hearts (ischaemic cardiomyopathy, ICM and dilated cardiomyopathy, DCM) and 13 non-failing donor hearts. The effect of insulin on isometric twitch force was examined with or without blocking of PI3-kinase, GLUT4-translocation, or SGLT-1. Substrate-dependent (glucose vs. pyruvate vs. palmitoyl-carnitine) effects were tested in atrial myocardium. mRNA expression of glucose transporters was analysed. Insulin increased developed force by 122 + or - 7.4, 121.7 + or - 2.5, and 134.1 + or - 5.7% in non-failing, DCM, and ICM (P < 0.05 vs. DCM), respectively. Positive inotropic effect was partially blunted by inhibition of PI-3-kinase, GLUT4, or SGLT1. Combined inhibition of PI3-kinase and glucose-transport completely abolished PIE. Positive inotropic effect was significantly stronger in glucose-containing solution compared with pyruvate or palmitoyl-carnitine containing. mRNA expression showed only a tendency towards elevated GLUT4-expression in ICM.

CONCLUSIONS

Positive inotropic effect of insulin is pronounced in ICM, but underlying mechanisms are unaltered. The Ca(2+)-independent PIE of insulin is mediated via glucose-transporters. Together with the Ca(2+)-dependent PI-3-kinase mediated pathway, it is responsible for the entire PIE. Substrate-dependency affirms a glucose-dependent part of the PIE.

Glucose-transporter-mediated positive inotropic effects in human myocardium of diabetic and nondiabetic patients

Insulin causes inotropic effects via Ca(2+)-dependent and Ca(2+)-independent pathways. The latter one is potentially glucose dependent. We examined inotropic responses and signal transduction of insulin in human atrial myocardium of diabetic and nondiabetic patients to test for the role of glucose transporters. Experiments were performed in isolated atrial myocardium of 88 patients undergoing cardiac surgery and 28 ventricular muscle samples of explanted hearts. Influence of insulin (0.02 micromol/L) on isometric twitch force was examined with and without blocking glucose transporter (GLUT) 4 translocation (latrunculin), sodium-coupled glucose transporter (SGLT) 1 (phlorizin, T-1095A), or PI3-kinase (wortmannin). Experiments were performed in Tyrode solution containing glucose or pyruvate as energetic substrate. Messenger RNA expression of glucose transporters (GLUT1, GLUT4, SGLT1, SGLT2) was analyzed in atrial and ventricular myocardium of both diabetic and nondiabetic patients. Developed force increases after insulin (to 117.8% +/- 2.4% and 115.8% +/- 1.9%) in trabeculae from patients with and without diabetes. Inotropic effect was reduced after displacing glucose with pyruvate as well as after PI3-kinase inhibition (to 103% +/- 2%) or inhibition of glucose transporters GLUT4 (to 105% +/- 2%) and SGLT1 (phlorizin to 106% +/- 2%, T-1095A to 105% +/- 2%), without differences between the 2 groups. In glucose-free pyruvate-containing solution, only inhibition of PI3-kinase but not blocking glucose transporters resulted in further inhibitory effects. Messenger RNA expression did not show significant differences between patients with or without diabetes. Insulin exerts positive inotropic effects in human atrial myocardium. These effects are mediated via a PI3-kinase-sensitive and a glucose-transport-sensitive pathway. Differences in functional effects or messenger RNA expression of glucose transporters were not detectable between patients with and without diabetes.

Diabetes and incident heart failure in hypertensive and normotensive participants of the Strong Heart Study

OBJECTIVES

Type 2 diabetes is accepted as a cause of heart failure, but direct cause-effect evidence independent of incident myocardial infarction (MI), hypertension and other coexisting risk factors is less well studied. We tested the hypothesis that diabetes predisposes to heart failure independently of hypertension and intercurrent MI.

METHODS

We evaluated 12-year incident heart failure in 2740 participants (1781 women) without prevalent cardiovascular or severe kidney disease, at the time of the first exam of the Strong Heart Study cohort. Intercurrent MI was censored as a competing risk event.

RESULTS

Diabetes was present in 1206 individuals (44%), and impaired fasting glucose (IFG) in 391 (14%). Diabetic participants more frequently had hypertension and/or central obesity (both P < 0.0001). Incident heart failure was ascertained in 64 participants with normal fasting glucose (NFG; 6%), 26 (7%) with IFG and 201 with diabetes (17%, hazard ratio = 4.04 vs. NFG, P < 0.0001). In Cox analysis adjusting for age, sex, obesity, central fat distribution, hypertension, antihypertensive medications, prevalent atrial fibrillation, glomerular filtration rate, urinary albumin/creatinine ratio, plasma cholesterol, Hb1Ac, smoking habit, alcohol use, educational level and physical activity, diabetes was associated with a two-fold greater risk of incident heart failure than NFG (hazard ratio = 2.45, P < 0.0001). Diabetes maintained 1.5-fold greater risk of heart failure than NFG (P < 0.03) even when intercurrent MI (n = 221) was censored as a competing risk event, similar to the adjusted hazard ratio for heart failure in hypertension.

CONCLUSION

Type 2 diabetes is a potent, independent risk factor for heart failure. Risk of heart failure in diabetic patients cannot be fully explained by incident MI and coexisting cardiovascular risk factors. Mechanisms directly related to diabetes and impairing cardiac function should be studied and identified.