Correction to: Human heart shifts from IGF-1 production to utilization with chronic heart failure

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

A multistep approach for the stratification of the risk of severe hypoglycemia in patients with type 2 diabetes

INTRODUCTION

Hypoglycemia is the major limiting factor in the glycemic management of diabetes. Aim of this study was to produce a risk stratification tool to support the medical decision making, by facilitating the identification of patients at higher risk of hypoglycemia.

EVIDENCE ACQUISITION

A multistep approach was adopted, including a systematic review of observational studies investigating risk factors for severe hypoglycemia in type 2 diabetes (T2DM), followed by an expert input forum to identify factors perceived as relevant and at the same time reliably detectable, to be used for the development of a risk score.

EVIDENCE SYNTHESIS

The systematic review led to the identification of 41 studies. Many factors have been seldom investigated, and their association with the risk of hypoglycemia is still unclear. Factors more frequently associated with a high risk of hypoglycemia were: low level of education, ethnicity, irregular meals/malnutrition, insulin and sulfonylurea therapy, polypharmacy, previous hypoglycemia, impaired renal function, cognitive impairment, depression and frailty. The expert input forum involved 35 diabetologists. Following the ranking of the relevance of the factors identified, a parsimonious yet comprehensive set of risk factors was identified.

CONCLUSIONS

The process led to the identification of relevant factors, to be used for the development of a hypoglycemia risk score. An ad-hoc study will be performed to assess the contribution of these risk factors and their relative weight. If the risk score will confirm its ability to correctly stratify patients according to their risk of hypoglycemia, it will represent a useful support to optimize the care of people with T2DM.

More patients reach glycaemic control with a fixed-ratio combination of insulin glargine and lixisenatide (iGlarLixi) than with basal insulin at 12 weeks of treatment: A post hoc time-to-control analysis of LixiLan-O and LixiLan-L

The present post hoc analysis of two 30-week clinical trials compared efficacy and hypoglycaemia outcomes at early study visits with iGlarLixi (insulin glargine U100 [iGlar] and lixisenatide) vs iGlar alone in patients with type 2 diabetes (T2D) uncontrolled on oral antidiabetic drugs (OADs; LixiLan-O trial) or basal insulin (LixiLan-L trial). Time to control, defined as days to achieve glycated haemoglobin (HbA1c) <53 mmol/mol (<7%) or fasting plasma glucose (FPG) ≤7.2 mmol/L, was estimated using the Kaplan-Meier method. In the LixiLan-O and LixiLan-L trials, 60% and 46% of patients, respectively, reached HbA1c <53 mmol/mol (<7%) with iGlarLixi at 12 weeks, vs 45% and 24%, respectively, with iGlar. In the LixiLan-O trial, the median time to target HbA1c was approximately half with iGlarLixi vs iGlar (85.0 vs 166.0 days; P < .0001). In the LixiLan-L trial, the median time to target HbA1c was 153.0 days with iGlarLixi, while target HbA1c was never reached by 50% of patients with iGlar (P < .0001). Time-to-target FPG and hypoglycaemia outcomes were similar between treatments. In T2D uncontrolled on OADs or basal insulin, iGlarLixi resulted in glycaemic control in more patients than did iGlar at early treatment time points.

Klinefelter syndrome, insulin resistance, metabolic syndrome, and diabetes: review of literature and clinical perspectives

PURPOSE

Klinefelter syndrome (KS), the most frequent chromosomic abnormality in males, is associated with hypergonadotropic hypogonadism and an increased risk of cardiovascular diseases (CVD). The mechanisms involved in increasing risk of cardiovascular morbidity and mortality are not completely understood. This review summarises the current understandings of the complex relationship between KS, metabolic syndrome and cardiovascular risk in order to plan future studies and improve current strategies to reduce mortality in this high-risk population.

METHODS

We searched PubMed, Web of Science, and Scopus for manuscripts published prior to November 2017 using key words "Klinefelter syndrome" AND "insulin resistance" OR "metabolic syndrome" OR "diabetes mellitus" OR "cardiovascular disease" OR "testosterone". Manuscripts were collated, studied and carried forward for discussion where appropriate.

RESULTS

Insulin resistance, metabolic syndrome, and type 2 diabetes are more frequently diagnosed in KS than in the general population; however, the contribution of hypogonadism to metabolic derangement is highly controversial. Whether this dangerous combination of risk factors fully explains the CVD burden of KS patients remains unclear. In addition, testosterone replacement therapy only exerts a marginal action on the CVD system.

CONCLUSION

Since fat accumulation and distribution seem to play a relevant role in triggering metabolic abnormalities, an early diagnosis and a tailored intervention strategy with drugs aimed at targeting excessive visceral fat deposition appear necessary in patients with KS.

Pregabalin-induced first degree atrioventricular block in a young patient treated for pain from extrapulmonary tuberculosis

<p>Pregabalin, widely used in the treatment of several pain disorders, is usually well tolerated. Uncommonly, the drug may induce cardiac side effects, rarely prolongation of the PR interval. The latter has never been described in patients with healthy heart or normal renal function. We characterize a unique case of a young man with extrapulmonary tuberculosis and no detectable or known cardiac or kidney diseases, treated with pregabalin to control the severe pain due to the involvement of the spinal cord by the tuberculosis, showing an atrioventricular (AV) block due to pregabalin administration. The reported case emphasizes the need of monitoring PR interval during treatment with pregabalin, even in patients without background of cardiac or renal diseases. </p>

Islet Transplantation under the Kidney Capsule Corrects the Defects in Glycogen Metabolism in Both Liver and Muscle of Streptozocin-Diabetic Rats

Insulin-deficient rats are characterized by multiple defects in the pathway of glycogen synthesis and breakdown in both liver and skeletal muscle. The aim of this study was to clarify whether islet transplantation under the kidney capsule, which is associated with delivery of insulin into the peripheral circulation, is able to normalize glycogen metabolism in liver and muscle of streptozotocin-diabetic rats. Three groups of male Lewis rats were studied under fasting condition: controls, untreated diabetics, and islet transplanted diabetics. Glycogen content, glucose-6-phosphate concentration, and glycogen synthase activity were measured in both liver and skeletal muscle. Untreated diabetic rats were characterized by an increase in glycogen content of 178% and a reduction of glucose-6-phosphate level of 50%. Both glycogen and glucose-6-phosphate contents were restored to normal in transplanted diabetic rats. Active glycogen synthase (0.35 ± 0.1 nmol/min/mg) and activity ratio (0.22 ± 0.04) were significantly impaired compared with controls (0.99 ± 0.2 nmol/min/mg and 0.43 ± 0.06, respectively) and were normalized by islet transplantation. In the skeletal muscle, glycogen content was similar in the three groups of animals, whereas muscle glucose-6-phosphate level was reduced by 28% and glycogen synthase was in a less active state in the untreated diabetic rats. Both the glucose-6-phosphate concentration and the kinetic profile of glycogen synthase were normalized by islet transplantation. In conclusion, islet transplantation under the kidney capsule corrects the diabetes-induced abnormalities in glycogen and glucose-6-phosphate content and glycogen synthase activity in both liver and skeletal muscle.

Beneficial effect of lixisenatide after 76 weeks of treatment in patients with type 2 diabetes mellitus: A meta-analysis from the GetGoal programme

AIMS

To evaluate the long-term efficacy and safety of lixisenatide, a short-acting, prandial glucagon-like peptide-1 receptor agonists (GLP-1 RA) as add-on therapy in type 2 diabetes mellitus.

METHODS

A meta-analysis of 76-week results of 5 placebo-controlled clinical trials from the GetGoal programme was performed, including 3000 inadequately controlled adult diabetic patients where lixisenatide 20 µg once-daily was administered in combination with metformin (GetGoal-M and GetGoal-F1), sulphonylurea ± metformin (GetGoal-S), basal insulin ± metformin (GetGoal-L) or pioglitazone ± metformin (GetGoal-P).

RESULTS

A significant reduction in HbA1c at 76 weeks was observed in the intervention arm compared to placebo (LSM difference: -0.41%, 95%CI: -0.51, -0.32, P < .00001). Compared to placebo, lixisenatide induced a larger decrease in fasting plasma glucose (LSM difference -0.49 mmol/L, 95% CI -0.71, -0.27, P < .0001) and postprandial glucose excursion after a standard test meal (LSM difference -3.29 mmol/L, 95% CI -4.17, -2.42, P < .00001). A bodyweight reduction was observed in the lixisenatide arm (LSM difference -0.40 kg, 95%CI: -0.8, -0.01, P = .05). The risk of hypoglycaemia was slightly higher with lixisenatide vs placebo (risk difference +0.02, 95% CI: 0, 0.04, P = .04). The most commonly observed non-severe adverse events were nausea and vomiting, which after week 16 and week 8, were steadily <4% and <1% in the lixisenatide arm, respectively.

CONCLUSIONS

Lixisenatide, a once-daily prandial GLP-1 RA, provides long-term glycaemic control, a sustained beneficial effect on weight and with a good safety profile.

The GH/IGF-1 axis in chronic heart failure

The classic model of Chronic Heart Failure (CHF) is rooted in the overexpression of neurohormonal molecules. To complement this paradigm, increasing evidence indicates that a variety of hormones may be down-regulated in CHF patients. The list includes growth hormone (GH) and its tissue effector insulin-like growth factor-1 (IGF-1). The GH/IGF-1 axis regulates cardiac growth, stimulates myocardial contractility, and influences the vascular system. The relationship between the GH/IGF-1 axis and the cardiovascular system has been extensively demonstrated in numerous studies in animals models and confirmed by the cardiac derangements secondary to both GH excess and deficiency in humans. Impaired activity of the GH/IGF-1 axis in CHF has been described by several independent groups and includes a wide array of abnormalities, including low IGF-1 levels, GH deficiency (GHD), and GH resistance that may be related to the severity of heart disease. According to several observations, these derangements are associated with poor clinical status and outcome. Since the first study of GH therapy in CHF in 1996, several placebo-controlled trials have been conducted with conflicting results. These discordant findings are likely explained by the degree of CHF-associated GH/IGF-1 impairment that may impact on individual responsiveness to GH administration. Biological actions of GH and IGF-1, cardiovascular implication of GH deficiency and GH excess, relation between somatotrophic axis and CHF are discussed. Results from trials of GH therapy, emerging therapeutic strategies, safety issues, and lack in evidence are also reported.

Migraine attack restores the response of vascular smooth muscle cells to nitric oxide but not to norepinephrine

AIM: To clarify whether the vasoconstrictory response is impaired and to study vascular function in patients with migraine during the headache attack.

METHODS: We studied vascular reactivity in the resistance arteries by using the forearm perfusion technique associated with plethysmography. We measured forearm blood flow by strain-gauge plethysmography during intra-brachial infusion of acetylcholine, sodium nitroprusside or norepinephrine in 11 controls and 13 patients with migraine, 11 of them (M) in the interval between the migraine attacks and 4 during a headache attack (MH). Written informed consent was obtained from patients and healthy controls, and the study was approved by the Ethics Committee of the University Federico II.

RESULTS: Compared to healthy control subjects, in patients with migraine studied during the interictal period, the vasodilating effect of acetylcholine, that acts through the stimulation of endothelial cells and the release of nitric oxide, was markedly reduced, but became normal during the headache attack (P < 0.05 by analysis of variance). The response to nitroprusside, which directly relaxes vascular smooth muscle cells (VSMCs), was depressed in patients with migraine studied during the interictal period, but normal during the headache attack (P < 0.005). During norepinephrine infusion, forearm blood flow decreased in control subjects (-40% ± 5%, P < 0.001). In contrast, in patients with migraine, either when studied during or free of the headache attack forearm blood flow did not change compared to the baseline value (-3% ± 13% and -10.4% ± 15%, P > 0.05).

CONCLUSION: In migrainers, the impaired relaxation of VSMCs is restored during the headache attack. The vasoconstrictory response is impaired and remains unchanged during the migraine attack.

Growth hormone replacement delays the progression of chronic heart failure combined with growth hormone deficiency: an extension of a randomized controlled single-blind study

OBJECTIVES

This study sought to evaluate the efficacy and safety of long-term growth hormone (GH) replacement therapy in GH-deficient patients with chronic heart failure (CHF).

BACKGROUND

Recent evidence indicates that growth hormone deficiency (GHD) affects as many as 40% of patients with CHF, and short-term GH replacement causes functional benefit. Whether long-term GH replacement also affects CHF progression is unknown.

METHODS

The study is an extension of a previous randomized, controlled single-blind trial that screened 158 consecutive CHF patients (New York Heart Association classes II to IV) and identified 63 who had GHD by the growth hormone releasing hormone plus arginine test. Fifty-six patients were randomized to receive either GH therapy or standard CHF therapy. Patients were evaluated at baseline and after a 4-year follow-up. The primary endpoint was peak oxygen consumption (VO2). Secondary endpoints included left ventricular (LV) ejection fraction and volumes, serum amino terminal fragment of the pro-hormone brain-type natriuretic peptide, quality of life, and safety.

RESULTS

Seventeen patients in the GH group and 14 in the control group completed the study. In the GH group, peak VO2 improved over the 4-year follow-up. The treatment effect was 7.1 ± 0.7 ml/kg/min versus -1.8 ± 0.5 ml/kg/min in the GH and control groups, respectively. At 4 years, LV ejection fraction increased by 10 ± 3% in the GH group, whereas it decreased by 2 ± 5% in control patients. The treatment effect on LV end-systolic volume index was -22 ± 6 ml and 8 ± 3 ml/m(2) in the GH and control groups, respectively (all p < 0.001). No major adverse events were reported in the patients who received GH.

CONCLUSIONS

Although this is a preliminary study, the finding suggests a new therapeutic approach to a large proportion of GHD patients with CHF.

Cardiovascular abnormalities in Klinefelter syndrome

BACKGROUND

Several epidemiological studies have demonstrated an increased mortality from cardiovascular causes in patients with Klinefelter Syndrome (KS). Little information is available about the nature of the underlying cardiovascular abnormalities. Aim of the study was to investigate exercise performance, left ventricular architecture and function, vascular reactivity, and carotid intima-media thickness in a group of patients with KS.

MATERIALS AND METHODS

Sixty-nine patients with KS and 48 age-matched controls participated in our population-controlled study. Forty-eight Klinefelter subjects were on testosterone treatment at the time of the investigation while 21 were naive and underwent a complete Doppler echocardiographic examination, a cardiopulmonary exercise test as well as a vascular study including measures of carotid intima-media thickness and endothelial function with flow-mediated dilation of the brachial artery. Patients with KS on testosterone therapy (n=48) were also matched against a population of men with treated secondary hypogonadism (n=21).

RESULTS

Patients with KS exhibited a wide array of cardiovascular abnormalities including left ventricular diastolic dysfunction, reduced maximal oxygen consumption (p<0.01), increased intima-media thickness (p<0.05) (-34% and +42% vs. controls, respectively) and a high prevalence of chronotropic incompetence (55% of patients, p<0.01). No significant difference was found between treated and untreated KS in variance with men treated for secondary hypogonadism.

CONCLUSION

Left ventricular diastolic dysfunction, impaired cardiopulmonary performance, chronotropic incompetence, and increased intima-media thickness suggest that cardiovascular abnormalities are a common finding in KS that is not reversed by testosterone replacement therapy and may represent the pathophysiological underpinnings of the increased risk of dying from heart disease.

Metformin prevents the development of chronic heart failure in the SHHF rat model

Insulin resistance is a recently identified mechanism involved in the pathophysiology of chronic heart failure (CHF). We investigated the effects of two insulin-sensitizing drugs (metformin and rosiglitazone) in a genetic model of spontaneously hypertensive, insulin-resistant rats (SHHF). Thirty SHHF rats were randomized into three treatment groups as follows: 1) metformin (100 mg/kg per day), 2) rosiglitazone (2 mg/kg per day), and 3) no drug. Ten Sprague-Dawley rats served as normal controls. At the end of the treatment period (12 months), the cardiac phenotype was characterized by histology, echocardiography, and isolated perfused heart studies. Metformin attenuated left ventricular (LV) remodeling, as shown by reduced LV volumes, wall stress, perivascular fibrosis, and cardiac lipid accumulation. Metformin improved both systolic and diastolic indices as well as myocardial mechanical efficiency, as shown by improved ability to convert metabolic energy into mechanical work. Metformin induced a marked activation of AMP-activated protein kinase, endothelial nitric oxide synthase, and vascular endothelial growth factor and reduced tumor necrosis factor-α expression and myocyte apoptosis. Rosiglitazone did not affect LV remodeling, increased perivascular fibrosis, and promoted further cardiac lipid accumulation. In conclusion, long-term treatment with metformin, but not with rosiglitazone, prevents the development of severe CHF in the SHHF model by a wide-spectrum interaction that involves molecular, structural, functional, and metabolic-energetic mechanisms.

Impaired diastolic function in naïve untreated human immunodeficiency virus infected patients

AIM

To evaluate cardiac function and structure in untreated human immunodeficiency virus (HIV) patients without clinical evidence of cardiovascular disease.

METHODS

Fifty-three naïve untreated HIV-infected patients and 56 healthy control subjects underwent clinical assessment, electrocardiography (ECG) and echocardiography, including tissue doppler imaging. Moreover, a set of laboratory parameters was obtained from all subjects, including HIV-RNA plasma levels, CD4 cell counts and tumor necrosis factor-α levels.

RESULTS

The two groups showed normal ECG traces and no differences regarding systolic morphologic parameters. In contrast, a higher prevalence of left ventricular diastolic dysfunction (abnormal relaxation or pseudonormal filling pattern) was found in the HIV patients (36% vs 9% in patients and controls, respectively, P <0.001).

CONCLUSION

Subclinical cardiac abnormalities appear in an early stage of the HIV infection, independent of antiretroviral therapy. The data suggest that HIV per se plays a role in the genesis of diastolic dysfunction.

Impaired endothelial- and nonendothelial-mediated vasodilation in patients with acute or chronic hypothyroidism

OBJECTIVE

Vascular dysfunction and accelerated atherosclerosis are prominent features of hypothyroidism. The relative roles of thyroid hormone (TH) deficiency and the associated vascular risk conditions are still unclear. We studied the impact of acute and chronic hypothyroidism on vascular reactivity.

PATIENTS

We studied 12 patients with chronic primary hypothyroidism (cHY; TSH: 52 +/- 14 mU/l), seven patients with acute hypothyroidism secondary to total thyroidectomy (aHY; TSH: 97 +/- 24) and 13 healthy subjects (TSH: 1.2 +/- 0.5).

MEASUREMENTS

We measured forearm blood flow (FBF) using plethysmography during intra-brachial infusion of: acetylcholine (ACh), sodium nitroprusside (NP) and norepinephrine (NE). We also measured serum C-reactive protein (CRP), TNF-alpha, asymmetric dimethylarginine (ADMA) and the forearm balance of nitric oxide (NO) during ACh infusion.

RESULTS

As compared with the controls, the vasodilatory response to ACh was reduced in cHY (P = 0.001) and aHY (P = 0.04), as was the forearm release of NO (P < 0.05). During NP infusion, FBF rose to 24 +/- 2 ml/dl/min in the controls and to significantly lower values in cHY (12 +/- 1; P = 0.001) and aHY (15 +/- 2; P = 0.004). NE-induced vasoconstriction was similar in the controls and aHY, but blunted in cHY. Serum CRP, TNF-alpha and ADMA were not different in the three groups.

CONCLUSIONS

(i) Hypothyroidism associates with endothelial and nonendothelial mediated vascular dysfunction; (ii) these defects are evident even after short-term hypothyroidism, indicating that TH deficiency per se is sufficient to alter vascular homeostasis; and (iii) chronic, but not acute, hypothyroidism impairs the vasoconstrictory effect of NE in the resistance vessels.

Insulin-like growth factor-1 protects from vascular stenosis and accelerates re-endothelialization in a rat model of carotid artery injury

BACKGROUND

IGF-1 is a potent mitogen for vascular smooth muscle cells, but exerts protective effects on endothelial cells that may trigger antiatherogenic mechanisms.

OBJECTIVES

This study was designed to test the hypothesis that an IGF-1 excess following arterial injury prevents neointima formation and vascular stenosis.

METHODS

Rats were subjected to carotid balloon injury and treated with IGF-1 (1.2 mg kg(-1) per die) or saline for 10 days.

RESULTS

In IGF-1 treated animals, high tissue levels of eNOS, Akt and its phosphorylated form were found, confirming activation of IGF-1-dependent signaling pathways. IGF-1 markedly reduced neointima formation and post-injury arterial stenosis. IGF-1 exerted proliferative and anti-apoptotic effects in the media of injured carotids, but inhibited mitotic activity and induced apoptosis in the neointima. Furthermore, IGF-1 stimulated mobilization of progenitor endothelial cells and re-endothelialization of the injured arteries. L-NAME administration inhibited IGF-1 vasculoprotective effects.

CONCLUSIONS

IGF-1 attenuates post-injury carotid stenosis by exerting differential effects in the neointima and tunica media with regard to the key components of the response to injury. The data point to a novel role of IGF-1 as a potent vasculoprotective factor.

Vascular smooth muscle cell dysfunction in patients with migraine

BACKGROUND

Migraine is associated with increased risk of cardiovascular disease, but the mechanisms are unclear.

OBJECTIVE

To investigate the activity of endothelial and vascular smooth muscle cells (VSMCs) in patients with migraine.

METHODS

Case-control study of 12 patients with migraine without aura and 12 matched healthy control subjects. Endothelial and VSMC components of vascular reactivity were explored by plethysmography measurement of forearm blood flow (FBF) during infusions of vasoactive agents into the brachial artery. Forearm production of nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) was also quantified.

RESULTS

In patients with migraine, the vasodilating effect of acetylcholine (ACh), an endothelium-dependent vasodilator, was markedly reduced (p < 0.001 by analysis of variance). In response to the highest dose of ACh, FBF rose to 8.6 +/- 2.2 in patients with migraine and to 22.7 +/- 3.0 mL x dL(-1) x min(-1) in controls (p = 0.001). The dose-response curve to nitroprusside, a vasodilator directly acting on VSMCs, was depressed in patients with migraine (p < 0.001 by analysis of variance). The maximal response of FBF to nitroprusside was 12.1 +/- 2.0 in patients with migraine and 24.1 +/- 1.8 mL x dl(-1) x min(-1) in controls (p < 0.001). During ACh infusion, NO release from the endothelium was similar in patients and controls. In contrast, there was a marked release of cGMP from VSMCs in controls, but not in patients with migraine (-1.9 +/- 2.2 in patients with migraine and -19.1 +/- 5.4 nmol x dL(-1) x min(-1) in controls; p = 0.03).

CONCLUSIONS

Patients with migraine are characterized by a distinct vascular smooth muscle cell dysfunction, revealed by impaired cyclic guanosine monophosphate and hemodynamic response to nitric oxide.