Effects of growth hormone and insulin-like growth factor-1 on cardiac hypertrophy of hypertensive patients

Mutual Effect Modification between Insulin Resistance and Endothelial Dysfunction in Predicting Incident Heart Failure in Hypertensives

Insulin resistance and endothelial dysfunction are associated with heart failure (HF). Our objective was to investigate whether endothelial dysfunction and insulin resistance are independent predictors of incident HF and if a possible interaction exists between them. We enrolled 705 white never-treated hypertensives. Endothelium-dependent vasodilation was investigated by intra-arterial infusion of acetylcholine. During the follow-up [median: 117 months (range: 31-211)], we documented 223 new cases of HF (3.3 events/100 patient-years). We stratified the study population into progressors and non-progressors; progressors showed an older age and a higher prevalence of females, as well as higher mean values of baseline glucose, insulin, homeostasis model assessment (HOMA), creatinine, and high-sensitivity C-reactive protein (hs-CRP), whereas the estimated glomerular filtration rate (e-GFR) and endothelium-dependent vasodilation were lower. In the multiple Cox regression analysis, serum hs-CRP (HR = 1.362, (95% CI = 1.208-1.536), HOMA (HR = 1.293, 95% CI = 1.142-1.465), maximal acetylcholine (Ach)-stimulated forearm blood flow (FBF) (100% increment, HR = 0.807, 95% CI = 0.697-0.934), and e-GFR (10 mL/min/1.73 m2 increment, HR = 0.552, 95% CI = 0.483-0.603) maintained an independent association with incident HF. HOMA and endothelial dysfunction interact between them in a competitive manner (HR = 6.548, 95% CI = 4.034-10.629), also showing a mutual effect modification. Our findings demonstrate that both endothelial dysfunction and HOMA are independent and strong predictors of incident HF in hypertensives, these two risk factors interact between them with a competitive mechanism.

Association between right ventricular dysfunction and adverse cardiac events in mild COPD patients

BACKGROUND

Lung hyperinflation and systemic inflammation are currently believed to be the most important causes of right heart alterations in chronic obstructive pulmonary disease (COPD) patients. A multicentre observational study was performed to assess the morphological and functional parameters of right ventricle (RV) in COPD subjects, as well as to evaluate the potential prognostic impact on the development of major cardiovascular adverse events (MACEs).

METHODS

For this retrospective study, from 1 January 2010 to 31 December 2021, we enrolled COPD patients on the basis of their airflow limitation. In particular, we selected subjects spanning across GOLD 1 and 2 functional stages. Clinical, laboratory and functional parameters were collected at baseline. Echocardiography was routinely performed in all COPD patients. RV dysfunction was defined on the basis of tricuspid annular plane systolic excursion (TAPSE) values. MACE occurrence (non-fatal ischemic stroke, non-fatal myocardial infarction, cardiac revascularization or coronary bypass surgery and cardiovascular death) was evaluated during a median follow-up of 55 (36-72) months.

RESULTS

Among the 749 enrolled patients, 408 subjects had a TAPSE value ≥20 mm, while the remaining 341 had a TAPSE value <20 mm. In patients with TAPSE ≥20 mm the observed MACEs were 1.9 events/100 patient-year, while in the group with a worse right heart function there were 4.2 events/100 patient-year (p < .0001). The multivariate analysis model confirmed the association between RV dysfunction and MACE. Indeed, a 1-mm increase in TAPSE value and the intake of long-acting β₂ -receptor agonists (LABA)/long-acting muscarinic antagonist (LAMA) inhaled therapy were protective factors for the onset of MACE, while the presence of diabetes mellitus and high values of both uric acid (UA) and systolic pulmonary arterial pressure (S-PAP) enhanced the risk of MACE in study participants.

CONCLUSIONS

The results of this study showed that in patients with mild COPD there is an association between right heart dysfunction and the risk of MACE during follow-up.

Relationship between circulating insulin-like growth factor-1 and blood pressure in adults: A systematic review and meta-analysis of observational studies

OBJECTIVE

Insulin-like growth factor 1 (IGF-1) is an important factor related to cardiovascular disease. In recent years, studies have shown the involvement of IGF-1 and blood pressure (BP). Nevertheless, the results were inconsistent. Thus, the purpose of this study was to systematically evaluate the associations of circulating IGF-1 levels with BP in adults.

METHODS

Two reviewers independently searched and screened articles from the Pubmed, EMBASE, Cochrane Library, CNKI, and WANFANG databases up to May 2020. A total of 12 studies that reported the correlation coefficients between IGF-1, systolic blood pressure (SBP), and diastolic blood pressure (DBP) were included.

RESULTS

IGF-1 was significantly correlated with SBP [r = -0.15; 95% CI = -0.21, -0.08; P < 0.0001] and DBP [r = -0.10; 95% CI = -0.16, -0.05; P = 0.0004]. Subgroup analysis further revealed that the relationship between IGF-1 and BP was influenced by race and age.

CONCLUSION

Circulating IGF-1 was negatively correlated with SBP and DBP. Further researches are necessary to explore the pathogenesis of this relationship and to evaluate the role of IGF-1 in the treatment of hypertension.

Cardiovascular Benefits of Extended-Time Nocturnal Hemodialysis

Hemodialysis (HD) remains the most utilized treatment for End-Stage Kidney Disease (ESKD) globally, mainly as conventional HD administered in 4 h sessions thrice weekly. Despite advances in HD delivery, patients with ESKD carry a heavy cardiovascular morbidity and mortality burden. This is associated with cardiac remodeling, left ventricular hypertrophy (LVH), myocardial stunning, hypertension, decreased heart rate variability, sleep apnea, coronary calcification and endothelial dysfunction. Therefore, intensive HD regimens closer to renal physiology were developed. They include longer, more frequent dialysis or both. Among them, Nocturnal Hemodialysis (NHD), carried out at night while asleep, provides efficient dialysis without excessive interference with daily activities. This regimen is closer to the physiology of the native kidneys. By providing increased clearance of small and middle molecular weight molecules, NHD can ameliorate uremic symptoms, control hyperphosphatemia and improve quality of life by allowing a liberal diet and free time during the day. Lastly, it improves reproductive biology leading to successful pregnancies. Conversion from conventional to NHD is followed by improved blood pressure control with fewer medications, regression of LVH, improved LV function, improved sleep apnea, and stabilization of coronary calcifications. These beneficial effects have been associated, among others, with better extracellular fluid volume control, improved endothelial- dependent vasodilation, decreased total peripheral resistance, decreased plasma norepinephrine levels and restoration of heart rate variability. Some of these effects represent improvements in outcomes used as surrogates of hard outcomes related to cardiovascular morbidity and mortality. In this review, we consider the cardiovascular effects of NHD.

The TRIB3 R84 variant is associated with increased left ventricular mass in a sample of 2426 White individuals

BACKGROUND

Prior studies in animal models showed that increased cardiac expression of TRIB3 has a pathogenic role in inducing left ventricular mass (LVM). Whether alterations in TRIB3 expression or function have a pathogenic role in inducing LVM increase also in humans is still unsettled. In order to address this issue, we took advantage of a nonsynonymous TRIB3 Q84R polymorphism (rs2295490), a gain-of-function amino acid substitution impairing insulin signalling, and action in primary human endothelial cells which has been associated with insulin resistance, and early vascular atherosclerosis.

METHODS

SNP rs2295490 was genotyped in 2426 White adults in whom LVM index (LVMI) was assessed by validated echocardiography-derived measures.

RESULTS

After adjusting for age and sex, LVMI progressively and significantly increased from 108 to 113, to 125 g/m2 in Q84Q, Q84R, and R84R individuals, respectively (Q84R vs. Q84Q, P = 0.03; R84R vs. Q84Q, P < 0.0001). The association between LVMI and the Q84R and R84R genotype remained significant after adjusting for blood pressure, smoking habit, fasting glucose levels, glucose tolerance status, anti-hypertensive treatments, and lipid-lowering therapy (Q84R vs. Q84Q, P = 0.01; R84R vs. Q84Q, P < 0.0001).

CONCLUSIONS

We found that the gain-of-function TRIB3 Q84R variant is significantly associated with left ventricular mass in a large sample of White nondiabetic individual of European ancestry.

A high triglyceride-glucose index is associated with left ventricular dysfunction and atherosclerosis

Background: The triglyceride-glucose (TyG) index has been reported to be a simple and reliable surrogate marker of insulin resistance. The aim of this study was to investigate associations between the TyG index and echocardiographic parameters including left ventricular mass (LVM), left atrial diameter (LAD) and left ventricular ejection fraction (LVEF), and markers of peripheral artery disease, ankle-brachial index (ABI) and brachial-ankle pulse wave velocity (baPWV). Methods: A total of 823 (483 males and 340 females) patients were enrolled from 2007 to 2011 at a regional hospital in southern Taiwan. Multivariable stepwise linear regression analysis was performed to identify the factors related to echocardiographic parameters and peripheral artery disease. Results: The patients were stratified into four groups according to TyG index quartile. Multivariable stepwise linear regression analysis showed that a higher TyG index was associated with elevated observed/predicted LVM (p = 0.081), increased LAD (p = 0.004), decreased LVEF (p = 0.003) and lower ABI (p = 0.030), but not observed/predicted LVM and baPWV. Conclusions: A high TyG index was significantly associated with high LAD, low LVEF and low ABI. However, the TyG index was not significantly associated with inappropriate LVM or baPWV. The results suggest that the TyG index, as a simple indicator of insulin resistance, may reflect cardiac remodeling and dysfunction and atherosclerosis.

Serum salusin-β in relation to atherosclerosis and ventricular dysfunction in patients with type 2 diabetes mellitus

BACKGROUND AND AIMS

Salusin-β is a newly defined biomarker that plays a role in atherogenesis and in homeostasis. The study aimed to assess serum salusin-β level in relation to atherosclerosis and ventricular dysfunction in type 2 diabetes mellitus (T2DM) patients.

METHODS

Sixty T2DM patients and twenty-five age-matched healthy controls were included. Serum salusin-β was determined by ELISA. Echocardiography and carotid ultrasonography were carried out for all individuals.

RESULTS

Serum salusin-β level was significantly elevated in patients with T2DM than in controls (P < 0.001). It was positively correlated with obesity parameters, insulin resistance index (r = 0.280,P < 0.001), atherogenic dyslipidemia and with carotid intima media thickness (CIMT) (r = 0.411, P < 0.001). Echocardiographic findings showed a positive correlation between salusin-β and left ventricular hypertrophy (LVH) parameters and a negative correlation with left ventricular (LV) diastolic and systolic functions. Regression analysis showed that serum salusin-β level was a significant predictor of diastolic dysfunction.

CONCLUSION

Serum salusin-β may be associated with atherosclerosis and LV dysfunction in T2DM.

Different Patterns of Left Ventricular Hypertrophy in Metabolically Healthy and Insulin-Resistant Obese Subjects

Obese subjects showed different cardiovascular risk depending by different insulin sensitivity status. We investigated the difference in left ventricular mass and geometry between metabolically healthy (MHO) and unhealthy (MUHO) obese subjects. From a cohort of 876 obese subjects (48.3 ± 14.1 years) without cardio-metabolic disease and stratified according to increasing values of Matsuda index after 75 g oral glucose tolerance test, we defined MHO (n = 292) those in the upper tertile and MUHO (n = 292) those in the lower tertile. All participants underwent echocardiographic measurements. Left ventricular mass was calculated by Devereux equation and normalized by height^2,7 and left ventricular hypertrophy (LVH) was defined by values >44 g/m^2.7 for females and >48 g/m^2.7 for males. Left ventricular geometric pattern was defined as concentric or eccentric if relative wall thickness was higher or lower than 0.42, respectively. MHO developed more commonly a concentric remodeling (19.9 vs. 9.9%; p = 0.001) and had a reduced risk for LVH (OR 0.46; p < 0.0001) than MUHO, in which the eccentric type was more prevalent (40.4 vs. 5.1%; p < 0.0001). We demonstrated that obese subjects-matched for age, gender and BMI-have different left ventricular mass and geometry due to different insulin sensitivity status, suggesting that diverse metabolic phenotypes lead to alternative myocardial adaptation.

Elevated 1-h post-load plasma glucose is associated with right ventricular morphofunctional parameters in hypertensive patients

PURPOSE

Emerging data demonstrate that type 2 diabetes mellitus (T2DM) is associated with right ventricular (RV) dysfunction. A cutoff point of 155 mg/dL for the 1-hour (h) post-load plasma glucose, during oral glucose tolerance test (OGTT), identifies patients with normal glucose tolerance (NGT) at high risk to develop T2DM and cardiovascular (CV) disease. We investigated if 1-h post-load glucose may affect RV geometry and function in a group of never-treated hypertensive individuals.

METHODS

We enrolled 446 Caucasian newly diagnosed hypertensive outpatients. All patients underwent an OGTT and a standard echocardiography. The tricuspid annular plane systolic excursion (TAPSE) and the RV fractional area change (RVFAC) were measured together with systolic pulmonary arterial pressure (s-PAP) and pulmonary vascular resistances (PVR). Insulin sensitivity was evaluated using the Matsuda index.

RESULTS

Among all partecipants, 296 had NGT, 100 impaired glucose tolerance (IGT), and 50 T2DM. Considering the cutoff point of 155 mg/dl for 1-h glucose, NGT subjects were stratified into two groups: NGT < 155 (n = 207), NGT ≥ 155 (n = 89). Subjects NGT ≥ 155 presented a worse metabolic and inflammatory profile than NGT < 155. RV functional parameters (TAPSE, RVFAC, TAPSE/s-PAP, and TAPSE/PVR) were significantly reduced in NGT ≥ 155 subjects compared with NGT < 155 patients. On the contrary, s-PAP and PVR were significantly higher. At multiple regression analysis, 1-h glucose was the strongest predictor of TAPSE in NGT ≥ 155, IGT, and T2DM.

CONCLUSIONS

The presence of RV impairment in hypertensive NGT ≥ 155 subjects further complicates their CV burden and it may, at least in part, justify the worse clinical outcome in this setting of patients.

Chronic HCV infection increases cardiac left ventricular mass index in normotensive patients

BACKGROUND & AIMS

Left ventricular hypertrophy (LVH), is an independent predictor for cardiovascular events. We investigated if chronic hepatitis C virus (HCV) infection and the related insulin resistance (IR)/hyperinsulinemia could influence the increase of left ventricular mass (LVM).

METHODS

We enrolled 260 outpatients matched for age, body mass index, gender, ethnicity: 52 with never-treated uncomplicated chronic HCV infection (HCV(+)), 104 never-treated hypertensives (HT) and 104 healthy subjects (NT). LVM was calculated according to the Devereux formula and indexed for body surface area. The following laboratory parameters were measured: fasting plasma glucose and insulin, total, LDL- and HDL-cholesterol, triglyceride, creatinine, e-GFR-EPI, HOMA. Quantitative HCV-RNA was assessed by PCR.

RESULTS

HCV(+) patients with respect to healthy normotensive subjects had an increased LVMI (100 ± 23 vs. 83 ± 15 g/m(2); p < 0.0001), similar to that observed in HT group (103 ± 25 g/m(2)). Regarding biochemical variables, HCV(+) patients, in comparison with normotensive healthy subjects, had higher triglyceride, creatinine, fasting insulin and HOMA (3.2 ± 1.3 vs. 2.5 ± 1.0; p < 0.0001). At linear regression analysis, the correlation between LVMI and HOMA was similar in HT (r = 0.528, p < 0.0001) and HCV(+) (r = 0.489, p < 0.0001) groups. At multiple regression analysis, HOMA resulted the major determinant of LMVI in all groups, explaining respectively 21.8%, 27.8%, and 23.9% of its variation in NT, HT and HCV(+). At correlational analysis HCV-RNA and HOMA demonstrated a strong and linear relationship between them, explaining the 72.4% of their variation (p = 0.022).

CONCLUSIONS

We demonstrated a significant and direct correlation between HOMA and LVMI in patients with chronic HCV infection, similar to that observed in hypertensives.

Renal disease and left atrial remodeling predict atrial fibrillation in patients with cardiovascular risk factors

OBJECTIVES

In this prospective population-based study, we tested the possible interaction between chronic kidney disease (CKD) and left atrium volume index (LAVI) in predicting incident atrial fibrillation (AF).

METHODS

We enrolled 3549 Caucasian subjects, 1829 men and 1720 women, aged 60.7 ± 10.6 years, without baseline AF and thyroid disorders. Echocardiographic left ventricular mass and LAVI were measured. Renal function was calculated by estimated glomerular filtration rate (e-GFR). To test the effect of some clinical confounders on incident AF, we constructed different models including clinical and laboratory parameters. AF diagnosis was made by standard electrocardiogram or 24-h ECG-Holter, hospital discharge diagnoses, and by the all-clinical documentation.

RESULTS

During the follow-up (53.3 ± 18.1 months), 546 subjects developed AF (4.5 events/100 patient-years). Progressors to AF were older, had a higher body mass index, blood pressure, LDL-cholesterol, glucose, cardiac mass, and LAVI, and had lower e-GFR. Hypertension, metabolic syndrome, diabetes, cardiac hypertrophy and CKD were more common among AF cases than controls. In the final Cox regression model, variables that remained significantly associated with AF were: cardiac hypertrophy (HR=1.495, 95% CI=1.215-1.841), renal disease (HR=1.528, 95% CI=1.261-1.851), age (HR=1.586, 95% CI=1.461-1.725) and LAVI (HR=2.920, 95% CI=2.426-3.515). The interaction analysis demonstrated a synergic effect between CKD and cardiac hypertrophy (HR=4.040, 95% CI=2.661-6.133), as well as between CKD and LAVI (HR=4.875, 95% CI=2.699-8.805). The coexistence of all three subclinical organ damages significantly increases the arrhythmic risk (HR=7.185, 95% CI=5.041-10.240).

CONCLUSIONS

Our data demonstrate that LAVI and CKD significantly interact in a synergic manner in increasing AF risk.

A polymorphism at IGF1 locus is associated with carotid intima media thickness and endothelium-dependent vasodilatation

OBJECTIVE

Whether IGF-1 has a protective or a detrimental role in vascular homeostasis remains unsettled. There is evidence that the C/T polymorphism rs35767 near the promoter region of the IGF1 gene located in chromosome 12 is associated with plasma IGF-1 levels. We investigated the effects of this polymorphism on circulating IGF-1 levels, carotid intima media thickness (cIMT) and endothelial-dependent vasodilation.

METHODS

Two samples of adult nondiabetic Whites were studied. Sample 1 comprised 1124 individuals in whom cIMT was measured by ultrasonography. Sample 2 included 162 drug-naïve hypertensive individuals in whom endothelium-dependent and endothelium-independent vasodilation were assessed by intra-arterial infusion of acetylcholine (ACh), and sodium nitroprusside (SNP), respectively. IGF-1 was determined by chemiluminescent immunoassay. rs35767 polymorphism was screened using a TaqMan allelic discrimination assay.

RESULTS

In sample 1, IGF-1 levels were higher in subjects carrying the T allele compared with CC carriers (178 ± 78 vs. 166 ± 60 ng/mL, respectively; P = 0.007 adjusted for age, gender, and BMI). cIMT was lower in subjects carrying the T allele compared with CC carriers (0.71 ± 0.20 vs. 0.76 ± 0.22 mm, respectively; P < 0.0001 adjusted for age, gender, and BMI). In sample 2, maximally ACh-stimulated forearm blood flow was higher in subjects carrying the T allele compared with CC carriers (343 ± 191 vs. 281 ± 125%, respectively; P = 0.02 adjusted for age, gender, and BMI).

CONCLUSION

Subjects carrying the T allele exhibited significantly higher levels of circulating IGF-1, lower values of cIMT, and higher endothelium-dependent vasodilatation compared with CC carriers. These findings support the idea that IGF-1 plays a role in the pathogenesis of atherosclerosis.

Modulation of microRNAs in hypertension-induced arterial remodeling through the β1 and β3-adrenoreceptor pathways

BACKGROUND

Dysregulation of microRNAs (miRNAs) in arterial dysfunction and hypertension has not been extensively investigated yet. This project determined the effects of two anti-hypertensive β1 adrenergic selective blockers on miRNA expression in the Dahl Salt Sensitive (DSS) hypertensive rat model.

METHODS AND RESULTS

Microarray analysis showed that a set of miRNAs is differently expressed in the aorta of high salt (HS) treated rats with miR-320 increased and miR-26b and -21 decreased. All of these changes were reverted to normal by nebivolol (NEB, a β1 selective-blocker and β3 activator). The selective β3-adrenoceptor antagonist S-(-)-cyanopindolol (Syc) counteracted the effect of NEB on these miRNAs. Atenolol (ATN, a pure β1-blocker) combined with specific β3 agonist BRL37344 restored the expression of all three miRNAs, similar to NEB, while ATN alone had only a partial effect on miR-320 expression. Computational analysis found Insulin Growth Factor-1 Receptor (IGF1R) as a putative target of miR-320, and Phosphatase and tensin homolog on chromosome ten (PTEN) as a putative target of miR-26b and -21. The targets were verified by luciferase reporter assays. Inhibition of miR-320 by an antisense inhibitor or NEB increased IGF1R expression, while miR-320 overexpression reversed the effect of NEB. Overexpression of miR-26b or -21 or NEB decreased PTEN levels, while inhibition of miR-26b or -21 attenuated the effect of NEB. HS diet induced downregulation of IGF1R and upregulation of PTEN in the aorta. NEB normalized the aberrant expression of IGF1R and PTEN and also improved the impairment of vascular AKT/eNOS signaling. Moreover, both NEB and ATN showed to have protective effects on salt-induced hypertension, oxidative stress, and vascular remodeling. NEB had a greater effect than ATN.

CONCLUSIONS

Our data supports a differential miRNA expression profile in salt-induced hypertension. Manipulation of dysregulated miRNAs by β-blockers may substantially induce alterations of gene expression and prevent arterial dysfunction and remodeling.

One-hour post-load plasma glucose and IGF-1 in hypertensive patients

BACKGROUND

In normoglucose-tolerant subjects (NGT), 1-h post-load plasma glucose value ≥155 mg/dL, during an oral glucose tolerance test (OGTT), is associated with an increased risk of type-2 diabetes (T2D) and subclinical organ damage. Insulin-like growth factor-1 (IGF-1) is involved in the pathogenesis of insulin resistance (IR) and T2D. Moreover, hypertensives have different degrees of IR and different levels of IGF-1. Actually, there are no data supporting the association between post-load glucose and IGF-1; thus, the aim of the study was to investigate this relationship.

MATERIALS AND METHODS

We enrolled 1126 never-treated hypertensive subjects who underwent an OGTT and clinical characterization. Insulin sensitivity was assessed by the Matsuda index. IGF-1 was measured by a sensitive immunoradiometric assay.

RESULTS

Among participants, 764 had NGT, 263 had impaired glucose tolerance (IGT) and 99 had T2D. According to the 1-h post-load plasma glucose cut-off point of 155 mg/dL, we divided NGT subjects into NGT < 155 mg/dL and NGT ≥ 155 mg/dL. NGT ≥ 155 in comparison with NGT < 155 had significantly reduced insulin sensitivity and IGF-1 levels. At multiple regression analysis, IGF-1 was the major determinant of 1-h post-load glucose in NGT ≥ 155 subjects, IGT and diabetics, accounting for 20·9%, 17·7% and 15·5% of its variation in the respective models.

CONCLUSIONS

In hypertensive NGT ≥ 155 subjects, IGF-1 results strongly associated with 1-h post-load glucose, similarly to that observed in IGT and diabetics. This finding has clinical relevance because both low IGF-1 levels and 1-h post-load glucose in NGT subjects are associated with subclinical organ damage, an independent predictor of cardiovascular events.

Effect of frequent or extended hemodialysis on cardiovascular parameters: a meta-analysis

BACKGROUND

Increased left ventricular (LV) mass is a risk factor for cardiovascular mortality in patients with chronic kidney failure. More frequent or extended hemodialysis (HD) has been hypothesized to have a beneficial effect on LV mass.

STUDY DESIGN

Meta-analysis.

SETTING & POPULATION

MEDLINE literature search (inception to April 2011), Cochrane Central Register of Controlled Trials and ClinicalTrials.gov using the search terms "short daily HD," "daily HD," "quotidian HD," "frequent HD," "intensive HD," "nocturnal HD," and "home HD."

SELECTION CRITERIA FOR STUDIES

Single-arm cohort studies (with pre- and post-study evaluations) and trials examining the effect of frequent or extended HD on cardiac morphology and function and blood pressure parameters. Studies of hemofiltration, hemodiafiltration, and peritoneal dialysis were excluded.

INTERVENTION

Frequent (2-8 hours, >3 times weekly) or extended (>4 hours, 3 times weekly) HD compared with conventional (≤4 hours, 3 times weekly) HD.

OUTCOMES

Absolute changes in cardiac morphology and function, including LV mass index (LVMI; primary) and blood pressure parameters (secondary).

RESULTS

We identified 38 single-arm studies, 5 crossover trials, and 3 randomized controlled trials. By meta-analysis of 23 study arms, frequent or extended HD significantly reduced LVMI from baseline (-31.2 g/m(2), 95% CI, -39.8 to -22.5; P < 0.001). The 3 randomized trials found a less pronounced net reduction in LVMI (-7.0 g/m(2); 95% CI, -10.2 to -3.7; P < 0.001). LV ejection fraction improved by 6.7% (95% CI, 1.6% to 11.9%; P = 0.01). Other cardiac morphologic parameters showed similar improvements. There also were significant decreases in systolic, diastolic, and mean blood pressure and mean number of antihypertensive medications.

LIMITATIONS

Paucity of randomized controlled trials.

CONCLUSIONS

Conversion from conventional to frequent or extended HD is associated with improvements in cardiac morphology and function, including LVMI and LV ejection fraction, respectively, and several blood pressure parameters, which collectively might confer long-term cardiovascular benefit. Trials with long-term clinical outcomes are needed.

One-hour postload plasma glucose levels and left ventricular mass in hypertensive patients

OBJECTIVE

Left ventricular hypertrophy (LVH), an independent risk factor for cardiovascular (CV) morbidity and mortality, recognizes a multifactorial pathogenesis. A plasma glucose value ≥155 mg/dL for the 1-h postload plasma glucose during an oral glucose tolerance test (OGTT) identifies subjects with normal glucose tolerance (NGT) at high risk for type 2 diabetes. We addressed the question if glucose tolerance status, particularly 1-h postload plasma glucose levels, affects left ventricular mass (LVM) and cardiac geometry in essential hypertension.

RESEARCH DESIGN AND METHODS

We enrolled 767 never-treated hypertensive subjects, 393 women and 374 men (mean age 49.6 ± 8.5 years). All patients underwent an OGTT for the evaluation of glucose tolerance and standard echocardiography. LVM was calculated using the Devereux formula and normalized by body surface area (LVM index [LVMI]). Insulin sensitivity was assessed by the Matsuda index. Among all participants, 514 had NGT, 168 had impaired glucose tolerance (IGT), and 85 had type 2 diabetes. According to the 1-h postload plasma glucose cutoff point of 155 mg/dL, we divided normotolerant subjects into two groups: NGT <155 mg/dL (n = 356) and NGT ≥155 mg/dL (n = 158).

RESULTS

Subjects in the NGT ≥155 mg/dL group had worse insulin sensitivity than subjects in the NGT <155 mg/dL group (Matsuda index 63.9 vs. 88.8; P < 0.0001). Men with NGT ≥155 mg/dL had a higher LVMI than men with NGT <155 mg/dL (126.6 vs. 114.3 g/m(2); P = 0.002) and a different LVH prevalence (41.1 vs. 25.8%; P < 0.0001). At multiple regression analysis, 1-h glucose resulted in the major determinant of LVMI in normotolerant, IGT, and diabetic groups.

CONCLUSIONS

These data show that NGT ≥155 mg/dL subjects, compared with NGT <155 mg/dL subjects, have a higher LVMI and a greater prevalence of LVH similar to that of IGT and diabetic patients.

IGF-1 and atherothrombosis: relevance to pathophysiology and therapy

IGF-1 (insulin-like growth factor-1) plays a unique role in the cell protection of multiple systems, where its fine-tuned signal transduction helps to preserve tissues from hypoxia, ischaemia and oxidative stress, thus mediating functional homoeostatic adjustments. In contrast, its deprivation results in apoptosis and dysfunction. Many prospective epidemiological surveys have associated low IGF-1 levels with late mortality, MI (myocardial infarction), HF (heart failure) and diabetes. Interventional studies suggest that IGF-1 has anti-atherogenic actions, owing to its multifaceted impact on cardiovascular risk factors and diseases. The metabolic ability of IGF-1 in coupling vasodilation with improved function plays a key role in these actions. The endothelial-protective, anti-platelet and anti-thrombotic activities of IGF-1 exert critical effects in preventing both vascular damage and mechanisms that lead to unstable coronary plaques and syndromes. The pro-survival and anti-inflammatory short-term properties of IGF-1 appear to reduce infarct size and improve LV (left ventricular) remodelling after MI. An immune-modulatory ability, which is able to suppress 'friendly fire' and autoreactivity, is a proposed important additional mechanism explaining the anti-thrombotic and anti-remodelling activities of IGF-1. The concern of cancer risk raised by long-term therapy with IGF-1, however, deserves further study. In the present review, we discuss the large body of published evidence and review data on rhIGF-1 (recombinant human IGF-1) administration in cardiovascular disease and diabetes, with a focus on dosage and safety issues. Perhaps the time has come for the regenerative properties of IGF-1 to be assessed as a new pharmacological tool in cardiovascular medicine.

Positive association between plasma IGF1 and high-density lipoprotein cholesterol levels in adult nondiabetic subjects

AIMS

Low IGF1 levels have been associated with an increased cardiovascular risk. It is unknown however whether IGF1 mediates the atherosclerotic process by modulating high-density lipoprotein cholesterol (HDL-C) independently from confounders. To address this issue, we evaluated the association between IGF1 levels and HDL-C in nondiabetic subjects.

METHODS

A cross-sectional analysis was used in the context of the CAtanzaro MEtabolic RIsk factors Study. One thousand and four participants (aged 20-69 years), for whom HDL-C and IGF1 measurements were available, were eligible for the study.

RESULTS

After adjusting for gender and age, IGF1 levels were positively correlated with HDL-C, and negatively correlated with body mass index (BMI), waist circumference, blood pressure (BP), triglyceride, fasting insulin, and homeostasis model assessment (HOMA). In a logistic regression model adjusted for age and gender, IGF1 in the lowest tertile (<125 ng/ml) was associated with an increased risk of having low HDL-C (odds ratio (OR) 2.14, 95% confidence interval (CI) 1.4-3.0; P=4x10(-5)) compared with the highest tertile (>186 ng/ml). When BMI, waist circumference, total cholesterol, triglyceride, and HOMA index were added to the model, IGF1 remained significantly associated with increased risk of low HDL-C (OR 1.52, 95% CI 1.01-2.31; P=0.04). A stepwise multivariate regression analysis in a model including age, gender, BMI, total cholesterol, triglycerides, IGF1, HOMA, and BP showed that the variables significantly associated with HDL-C were gender (P<0.0001), triglycerides (P<0.0001), total cholesterol (P<0.0001), BMI (P<0.0001), IGF1 levels (P<0.0001), and HOMA (P=0.001), accounting for 32.6% of its variation.

CONCLUSIONS

These data provide evidence that IGF1 may be an independent modulator for HDL-C in nondiabetic individuals.

Elevated one-hour post-load plasma glucose levels identifies subjects with normal glucose tolerance but early carotid atherosclerosis

OBJECTIVE

To examine whether individuals with normal glucose tolerance (NGT), whose 1-h post-load plasma glucose is >or=155 mg/dl, or with impaired glucose tolerance (IGT) have an increased carotid intima-media thickness (IMT), as compared with NGT individuals with 1-h post-load plasma <155 mg/dl.

METHODS

Atherosclerosis risk factors, oral glucose tolerance test (OGTT), and ultrasound manual measurement of IMT were analyzed in 400 non-diabetic Caucasians.

RESULTS

As compared with individuals with a 1-h post-load plasma glucose <155 mg/dl, NGT individuals with a 1-h post-load plasma glucose >or=155 mg/dl exhibited higher hsCRP (2.0+/-1.5 vs. 1.5+/-1.0, P=0.008), and IMT (0.82+/-0.20 vs. 0.71+/-0.16; P=0.006), and lower insulin sensitivity (71+/-39 vs. 105+/-57; P<0.0001), and IGF-1 levels (214+/-88 vs. 176+/-49; P<0.03). No significant differences were observed in metabolic and cardiovascular risk factors between IGT and NGT subjects with a 1-h post-load glucose >or=155 mg/dl. Of the three glycemic parameters, 1-h and 2-h post-load glucose, but not fasting glucose, were significantly correlated with IMT. In a stepwise multivariate regression analysis in a model including age, gender, and a variety of atherosclerosis risk factors, the three variables that remained significantly associated with IMT were age (P<0.0001), BMI (P<0.0001), and 1-h post-load glucose (P=0.02) accounting for 20.2% of its variation.

CONCLUSIONS

NGT subjects with a 1-h post-load glucose >or=155 mg/dl have an atherogenic profile similar to IGT individuals. These data suggest that a cutoff point of 155 mg/dl for the 1-h post-load glucose during OGTT may be helpful in the identification of NGT subjects at increased risk for cardiovascular disease.

Association of adiponectin with procollagen type I carboxyterminal propeptide in non-diabetic essential hypertension

OBJECTIVE

The serum concentration of procollagen type I carboxyterminal propeptide (PICP) is a good marker for collagen deposition in hypertension. Increased collagen deposition was associated with myocardial fibrosis and increased arterial stiffness. A decreased adiponectin level is associated with increased atherosclerosis. The role of adiponectin and its relation to PICP in essential hypertension have rarely been studied before.

METHODS

We recruited 188 non-diabetic uncomplicated hypertensive patients (mean age: 41+/-7 years; 128 men). No patient had vascular complications or renal or liver diseases. Overnight fasting blood samples were collected to assess patient lipid profiles, blood sugar, insulin, high-sensitivity C-reactive protein (hsCRP), PICP and adiponectin. Carotid to radial pulse wave velocity (PWV) measured using tonometry was used as an index of arterial stiffness.

RESULTS

Adiponectin (r = -0.216, p = 0.003) and male gender (p<0.001) were independent determinants of PICP. Diastolic blood pressure (r = 0.422, p<0.001) and current smoking (p = 0.005) were independent determinants of PWV. PWV was significantly correlated with PICP (r = 0.156, p = 0.034). Adiponectin was significantly correlated with triglyceride (r = -0.276, p<0.001), high-density lipoprotein (r = 0.262, p<0.001), the homeostasis model assessment (HOMA) index (r = -0.220, p = 0.002), hsCRP (r = -0.207, p = 0.004) and the body mass index (BMI) (r = -0.202, p = 0.005). After compensation with possible confounding factors, adiponectin was still significantly correlated with PICP (beta = -0.196, p = 0.006).

CONCLUSION

Serum adiponectin may be a marker for metabolic syndrome in essential hypertension. Adiponectin was significantly negatively correlated with PICP. Metabolic syndrome probably plays an important role in increased collagen synthesis and arterial stiffness through the effects of decreased adiponectin in non-diabetic essential hypertension.

Molecular genetics of human growth hormone, insulin-like growth factors and their pathways in common disease

The human growth hormone gene (GH1) and the insulin-like growth factor 1 and 2 genes (IGF1 and IGF2) encode the central elements of a key pathway influencing growth in humans. This "growth pathway" also includes transcription factors, agonists, antagonists, receptors, binding proteins, and endocrine factors that constitute an intrincate network of feedback loops. GH1 is evolutionarily coupled with other genes in linkage disequilibrium in 17q24.2, and the same applies to IGF2 in 11p15.5. In contrast, IGF1 in 12q22-24.1 is not in strong linkage disequilibrium with neighbouring genes. Knowledge of the functional architecture of these regions is important for the understanding of the combined evolution and function of GH1, IGF2 and IGF1 in relation to complex diseases. A number of mutations accounting for rare Mendelian disorders have been described in GH-IGF elements. The constellation of genes in this key pathway contains potential candidates in a number of complex diseases, including growth disorders, metabolic syndrome, diabetes (notably IGF2BP2) cardiovascular disease, and central nervous system diseases, and in longevity, aging and cancer. We review these genes and their associations with disease phenotypes, with special attention to metabolic risk traits.