Phenotypic characterization of normotolerant hypertensive patients

Immuno-Mediated Inflammation in Hypertensive Patients with 1-h Post-Load Hyperglycemia

Inflammation plays a key role in the pathogenesis/progression of atherosclerosis, and inflammatory molecules contribute to the progression of cardiovascular disease. Subjects with normal post-load glucose tolerance and 1-h post-load plasma glucose >155 mg/dL have an increased risk of subclinical target organ damage and incident diabetes. We aimed to test possible differences in immune-mediated inflammatory parameters in newly-diagnosed hypertensives with or without 1-h post-load hyperglycemia. We enrolled 25 normotensives (NGT) and 50 hypertensives normotolerant on oral glucose tolerance test, further divided into two groups based on 1-h post-load plasma glucose: NGT 1-h ≥ 155 (n = 25) and NGT 1-h < 155 (n = 25). We measured toll-like receptor (TLR) 2, TLR4, nuclear factor kβ (NF-kβ), interleukin (IL)-1β, IL-6, IL-8, IL-10, and tumor necrosis factor (TNF)-α. Hypertensives showed significantly worse metabolic and lipid profiles, and higher values of body mass ass index (BMI), creatinine, and inflammatory parameters, compared to controls. NGT 1-h ≥ 155 had a worse glycometabolic profile and higher values of TLR2 (9.4 ± 4.2 vs. 5.9 ± 2.6 MFI), TLR4 (13.1 ± 3.9 vs. 7.8 ± 2.3 MFI), NF-kβ (0.21 ± 0.07 vs. 0.14 ± 0.04), IL-1β (6.9 ± 3.4 vs. 3.2 ± 2.1 pg/mL), IL-6 (10.8 ± 2.6 vs. 4.1 ± 1.6 pg/mL), IL-8 (27.6 ± 9.3 vs. 13.3 ± 5.6 pg/mL), TNF-α (6.4 ± 2.9 vs. 3.3 ± 1.4 pg/mL), and high-sensitivity C-reactive protein (hs-CRP) (4.8 ± 1.5 vs. 2.7 ± 1.0 mg/dL) in comparison with NGT 1-h < 155. Matsuda-index and 1-h post-load glycemia were retained as major predictors of TLRs and NF-kβ. These results contribute to better characterizing cardiovascular risk in hypertensives.

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.

Metabolic and vascular effects of silybin in hypertensive patients with high 1-h post-load plasma glucose

Hypertensive patients with normal glucose tolerance (NGT) but 1-h post-load plasma glucose ≥ 155 mg/dl (1-h high), during an oral glucose tolerance test (OGTT), show higher insulin resistance and multiple target organ damages. Experimental and clinical studies demonstrate that silybin presents anti-inflammatory and metabolic effects, improving insulin resistance and endothelial dysfunction. This study aims to evaluate the effects of the complex silybin-vitamin E and phospholipids on inflammatory, metabolic and vascular parameters in NGT 1-h high hypertensive patients. This is a pilot, single arm, interventional, longitudinal study enrolling 50 Caucasian NGT 1-h high hypertensive outpatients, 27 men and 23 women, age range 42-60 years (mean + SD = 52 ± 7). After 6 months of silybin intake, there is a significant improvement in metabolic profile. The glucose response during OGTT significantly improves (AUCglucose_0-120 309.6 ± 63.4 at baseline vs 254.6 ± 35.5 at the follow-up, ∆ = - 55, 95% CI from - 67 to - 43, p < 0.0001), so as insulin response (AUCinsulin_0-120 238.2 ± 99.1 vs 159.3 ± 44.9, ∆ = - 78.9, 95% CI from - 100.0 to - 57.8, p < 0.0001), in accordance with the increase of insulin sensitivity index Matsuda. Silybin intake is associated with a significant reduction of both clinical and central systolic blood pressure, with betterment in clinical and central pulse pressure and reduction of arterial stiffness parameters. In conclusion, this study demonstrates that silybin may improve the metabolic aspect and vascular damage in NGT 1-h high hypertensive patients who are at higher metabolic and cardiovascular risk. Thus, in these patients, silybin might strengthen the effect of antihypertensive drugs giving further cardiovascular protection.

Sympathovagal balance and 1-h postload plasma glucose in normoglucose tolerant hypertensive patients

AIMS

Normoglucose tolerant (NGT) subjects with a 1-h postload plasma glucose (PLPG) value ≥155 mg/dL have an increased risk of type-2 diabetes and subclinical organ damage. Heart rate variability (HRV) reflects cardiac autonomic balance, frequently impaired in course of diabetes. At this time, no data support the association between 1-h PLPG and HRV; thus, we investigated the possible association between 1-h PLPG and HRV.

METHODS

We enrolled 92 never-treated hypertensive subjects (56 women, 36 men), aged 55 ± 9.8 years. During OGTT, the patients underwent electrocardiographic recordings to evaluate HRV in the time domain (SDNN). Insulin sensitivity was assessed by Matsuda index.

RESULTS

Among participants, 56 were NGT, 20 had impaired glucose tolerance (IGT), and 16 had type-2 diabetes. According to the 1-h PLPG cutoff point of 155 mg/dL, we divided NGT subjects into: NGT < 155 (n = 38) and NGT ≥ 155 (n = 18). Glucose tolerance status was associated with a significant (P < 0.0001) increase in PLPG and insulin and the reduction in Matsuda index. In all groups, the SDNN values significantly (P < 0.0001) decreased during the first hour of OGTT. A complete recovery in NGT groups was observed at the end of the second hour; in IGT and type-2 diabetes, SDNN remained significantly lower with respect to baseline values. At multiple regression analysis, Matsuda index resulted in the only determinant of SDNN modification, explaining the 12.3 % of its variability.

CONCLUSIONS

Our data demonstrate that during OGTT, sympathovagal balance is acutely affected by both glucose and insulin modifications. Particularly, NGT ≥ 155 subjects behave in the same way of IGT and type-2 diabetes patients.

Dietary patterns and 1-h post-load glucose in essential hypertension

BACKGROUND AND AIMS

Normoglucosetolerants (NGT) are considered at low risk, even if a 1-h post-load glucose (PLG) value ≥ 155 mg dl(-1) identifies NGTs at high risk of type-2 diabetes (T2D) and sub-clinical organ damage. Specific dietary factors may affect insulin sensitivity and the risk of T2D. However, it is unknown whether dietary components affect 1-h PLG in hypertensive NGT. Therefore, we investigate the effect of dietary patterns on 1-h PLG.

METHODS AND RESULTS

We selected 188 subjects (94 NGTs < 155 mg dl(-1) and 94 NGTs ≥ 155 mg dl(-1) PLG), well matched for age, gender and body mass index (BMI). Insulin sensitivity was evaluated using the Matsuda index. Dietary intake was quantified by a semiquantitative food frequency questionnaire (FEQ) validated in the European Investigation into Cancer and Nutrition (EPIC) study. The NGT ≥ 155 group had significantly reduced insulin sensitivity (40.3 ± 19.8 vs. 73.3 ± 28.8; P < 0.0001). With the exclusion of total calories, lipids, alcohol and fiber consumption we observed a significant difference, between groups, in starch (214.1 ± 52.4 vs. 268.8 ± 71.8 g; P < 0.0001), saturated (27.4 ± 8.7 vs. 24.1 ± 8.5 g; P = 0.009), monounsaturated (45.5 ± 8.9 vs. 48.8 ± 10.7 g; P = 0.023) and polyunsaturated fatty acids (FAs) (14.5 ± 4.0 vs. 16.8 ± 4.7 g; P < 0.0001), fructose (14.5 ± 5.3 vs. 11.2 ± 4.8 g; P < 0.0001), and oligosaccharides (103.2 ± 26.6 vs. 89.9 ± 29.2 g; P = 0.001) consumption. In the whole population, starch was the major predictor of 1-h PLG, explaining 23.2% of variation (P < 0.0001). In the NGT < 155 group, fructose was the strongest predictor, accounting for 15.4% of the variation; BMI, gender and polyunsaturated FAs added another 6.6%, 3.6% and 3.2%, respectively. In the NGT ≥ 155 group, saturated and polyunsaturated FAs were retained as the major predictors of 1-h PLG, explaining 18.2% and 11.4% of the variation.

CONCLUSIONS

The present data demonstrate that dietary patterns affect 1-h PLG, remarking the importance of both quantitative and qualitative composition of a diet.

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.

Asymmetric dimethylarginine plasma levels and endothelial function in newly diagnosed type 2 diabetic patients

It is now well established that major risk factors for cardiovascular diseases (CVD) impact upon endothelial function by decreasing nitric oxide (NO) bioavailability. Asymmetric dimethylarginine (ADMA), an endogenous analog of l-arginine, is able to inhibit the activity of endothelial-NO synthase, promoting endothelial dysfunction. Type 2 diabetes (T2D) is characterized by a reduced endothelium-dependent vasodilation and increased ADMA levels and ADMA is strongly associated with micro- and macrovascular diabetic complications. However, there are not a lot of data about the role of ADMA on endothelial function in newly diagnosed T2D patients without cardiovascular (CV) complications. For this aim, we have enrolled forty-five newly diagnosed T2D patients, evaluated by a oral glucose tolerance test, and thirty normal subjects. Endothelium-dependent and -independent vasodilatation was investigated by intra-arterial infusion of increasing doses of acetylcholine (ACh) and sodium nitroprusside. ADMA was measured by high-performance liquid chromatography and insulin resistance (IR) by HOMA. Newly diagnosed T2D patients showed higher ADMA and l-arginine mean values in comparison with normal subjects and a significantly reduced ACh-stimulated forearm blood flow (FBF). In T2D patients FBF was significantly and inversely correlated with ADMA (r = −0.524, p < 0.0001) and in a multivariate regression analysis, ADMA resulted the stronger predictor of FBF, explaining the 27.5% of variability (p < 0.0001). In conclusion, ADMA was strongly related to endothelial dysfunction also in patients with newly diagnosed T2D, without clinically manifest vascular complications. This field is of great interest for understanding the mechanisms underlying the pathogenesis of diabetic disease and its CV complications.