Extracellular microRNAs and endothelial hyperglycaemic memory: a therapeutic opportunity?

Type 2 diabetes mellitus (T2DM) is a major cause of cardiovascular (CV) disease. Several large clinical trials have shown that the risk for patients with diabetes of developing CV complications is only partially reduced by early, intensive glycaemic control and lifestyle interventions, and that such complications result from changes in complex, not fully explored networks that contribute to the maintenance of endothelial function. The accumulation of senescent cells and the low-grade, systemic, inflammatory status that accompanies aging (inflammaging) are involved in the development of endothelial dysfunction. Such phenomena are modulated by epigenetic mechanisms, including microRNAs (miRNAs). MiRNAs can modulate virtually all gene transcripts. They can be secreted by living cells and taken up in active form by recipient cells, providing a new communication tool between tissues and organs. MiRNA deregulation has been associated with the development and progression of a number of age-related diseases, including the enduring gene expression changes seen in patients with diabetes. We review recent evidence on miRNA changes in T2DM, focusing on the ability of diabetes-associated miRNAs to modulate endothelial function, inflammaging and cellular senescence. We also discuss the hypothesis that miRNA-containing extracellular vesicles (i.e. exosomes and microvesicles) could be harnessed to restore a 'physiological' signature capable of preventing or delaying the harmful systemic effects of T2DM.

Low FasL levels promote proliferation of human bone marrow-derived mesenchymal stem cells, higher levels inhibit their differentiation into adipocytes.

Mesenchymal stem cells (MSCs) are multipotent progenitor cells that can differentiate into several cell types. Bone marrow (BM)-MSCs mainly differentiate into osteoblasts or adipocytes. MSC interactions with their microenvironment directly affect their self-renewal/differentiation program. Here, we show for the first time that Fas ligand (FasL), a well-explored proapoptotic cytokine, can promote proliferation of BM-derived MSCs in vitro and inhibits their differentiation into adipocytes. BM-MSCs treated with a low FasL dose (0.5 ng/ml) proliferated more rapidly than untreated cells without undergoing spontaneous differentiation or apoptosis, whereas higher doses (25 ng/ml) induced significant though not massive BM-MSC death, with surviving cells maintaining a stem cell phenotype. At the molecular level, 0.5 ng/ml FasL induced ERK1/2 phosphorylation and survivin upregulation, whereas 25 ng/ml FasL induced caspase activation. Importantly, 25 ng/ml FasL reversibly prevented BM-MSC differentiation into adipocytes by modulating peroxisome proliferator-activated receptor gamma (PPARγ) and FABP4/aP2 expression induced by adipogenic medium. All such effects were inhibited by anti-Fas neutralizing antibody. The in vitro data regarding adipogenesis were confirmed using Fas(lpr) mutant mice, where higher PPARγ and FABP4/aP2 mRNA and protein levels were documented in whole tibia. These data show for the first time that the FasL/Fas system can have a role in BM-MSC biology via regulation of both proliferation and adipogenesis, and may have clinical relevance because circulating Fas/FasL levels decline with age and several age-related conditions, including osteoporosis, are characterized by adipocyte accumulation in BM.

Ambulatory blood pressure monitoring and endothelium-dependent vasodilation in the elderly athletes.

AIM: Regular exercise is a key component of cardiovascular risk prevention strategies, because it is associated with a variety of beneficial metabolic and vascular effects that reduce mortality and the incidence of cardiovascular adverse events. Endothelium plays an important role in the local regulation of vascular tone and structure, mainly by nitric oxide (NO) synthesis and action. Aim of the present study was to evaluate in elderly athletes the effect of regular aerobic exercise on arterial blood pressure (BP) and on endothelium-dependent flow-mediated dilation (FMD) of the brachial artery. METHODS: The study population included 30 male subjects (mean age 65.6+/-5.6 years), who had practiced endurance running at a competitive level for at least 40 years, and 28 age- and sex-matched subjects (mean age 64.5+/-4.5 years) with sedentary lifestyle and free of cardiovascular disease. Athletes and control subjects underwent standard 12-lead ECG, clinic BP, 24-h ambulatory BP monitoring and endothelium-dependent FMD and endothelium-independent response to glyceryl trinitrate (GTN), 400 microg, in the brachial artery by high-resolution ultrasonography. RESULTS: Systolic clinic and ambulatory 24-h BP were significantly lower in the athletes, than in the controls (P<0.001, respectively). Systolic and diastolic 24-h BP variability, when assessed either by the standard deviation (S.D.), or by the coefficient of variation (CV), were also significantly lower in the athletes (P<0.01). The athletes also had a lower 24-h, day-time and night-time heart rate (HR) (P<0.01), as well as a lower HR variability (P<0.01). As regards circadian BP change, the %Delta was statistically significant greater in athletes (P<0.05). Elderly athletes showed higher FMD than elderly sedentary subjects (P<0.001), whereas no differences were shown in the response to GTN. CONCLUSIONS: Our results, suggest that long-term physical activity can counteract the age-related endothelial dysfunction that characterizes sedentary aging, preserving the capacity of the endothelium-dependent vasodilation and reduces BP values improving arterial pressure control.

Clinical follow-up of a woman with diffuse coronary ectasia and coronaro-left ventricular fistulae.

The presence in the same clinical case of diffuse coronary artery ectasia and multiple congenital coronary artery fistulae draining into the left ventricle is a very rare condition. Herein we report the 20-year follow-up of an 85-year old woman, in order to show that the long-term prognosis in such a double disorder is good.

Antihypertensive effect of oral potassium aspartate supplementation in mild to moderate arterial hypertension.

BACKGROUND: Previous studies showed that potassium chloride (48-120 mmol/day) supplementation reduced arterial blood pressure (BP) in hypertensive patients. OBJECTIVES: Our aim was to evaluate the effect of a lower dose of potassium aspartate salt on BP in individuals with essential arterial hypertension. METHODS: One hundred and four patients (65 males, age 53 +/- 12 years) with mild to moderate essential hypertension (systolic/diastolic BP 154.2/96.2 +/- 10.8/5.4 mmHg) were allocated in two comparable groups of 52 to receive or not 30 mmol/day per os of potassium aspartate supplementation for four weeks. Office and 24-h BP, as well as serum and urinary electrolytes, were measured at baseline and at the follow-up visit after four weeks. RESULTS: Office and 24-h BP did not change in the control group, while these values were significantly reduced in the potassium supplementation group. Changes in office (systolic BP: 154.4 +/- 8.2 vs. 142.2 +/- 7.6 mmHg; diastolic BP: 95.0 +/- 5.6 vs. 87.2 +/- 4.3 mmHg, P < 0.001 for both) and 24-h BP (systolic BP: 142.7 +/- 8.2 vs. 134.8 +/- 6.3 mmHg; diastolic BP: 90.8 +/- 4.4 vs. 84.6 +/- 3.8 mmHg, P < 0.001 for both) following potassium supplementation were highly significant. The changes in day time and night time BP were similar. The treated group showed significantly increased potassium serum level and 24-h urinary excretion of potassium (P < 0.01 in both cases) after four weeks, while the untreated group showed no significant changes of the same parameters. Urinary Na/K ratio decreased significantly with potassium supplementation (P < 0.001). In the treated group changes in office (r = 0.58, P < 0.001) and 24-h SBP (r = 0.51, P < 0.001), but not in DBP (r = 0.29 and r = 0.25, n.s.), correlated positively with the urinary Na/K ratio at baseline. CONCLUSIONS: A relatively low supplementation of 30 mmol/day of potassium as aspartate lowered office and 24-h ambulatory BP in subjects with mild to moderate essential hypertension. The antihypertensive effect was sustained throughout the day, and was greater in the patients with high basal urinary Na/K ratio.

QT dispersion in elderly athletes with left ventricular hypertrophy.

The purpose of this study was to examine the QT dispersion in elderly endurance athletes with left ventricular (LV) hypertrophy. Sixteen athletes (males, mean age 67.6 +/- 4.5 years) with mild to moderate LV hypertrophy, were compared with 16 age-matched hypertensive patients with similar degree of LV hypertrophy and 16 age-matched healthy sedentary controls. All the participants underwent echocardiogram and 12-lead electrocardiogram. QT dispersion was defined as the difference between maximum and minimum QT intervals in the different leads. QT dispersion was corrected (QTc) for heart rate according to Bazett's formula. The results showed in athletes and hypertensive patients comparable LV mass (258.2 +/- 14.2 vs. 262.4 +/- 16.8 g, ns), which was significantly higher than that of controls (p < 0.001). Trained subjects had QT dispersion (38.6 +/- 10.2 ms) and QTc dispersion (39.4 +/- 11.3 ms) significantly lower than hypertensive patients (QT dispersion: 68.4 +/- 11.4 ms; QTc dispersion: 72.2 +/- 8.4, p < 0.001) and comparable with controls (QT dispersion: 44.3 +/- 8.4 ms; QTc dispersion: 46.2 +/- 6.2 ms, ns). In conclusion, in elderly athletes training-induced myocardial hypertrophy was characterized by a QT dispersion significantly lower than hypertensive myocardial hypertrophy. This could provide a simple and inexpensive screening method for differentiating physiologic from pathologic myocardial hypertrophy in elderly subjects.

[QT dispersion in insulin-dependent diabetics]. / QT dispersione nei diabetici insulino-dipendenti.

BACKGROUND: The measurement of the dispersion of the QT interval reflects regional repolarization differences in the heart which in turn can elicit the onset of arrhythmias by means of re-entry mechanism. Therefore, inter-lead QT dispersion has been proposed as novel indicator of arrhythmogenic risk that can predict severe ventricular arrhythmias or sudden death. The present study was conducted to evaluate QT dispersion in diabetic insulin-dependent patients with autonomic neuropathy. METHODS: We recruited three groups of 10 patients with the same age, sex, body weight distribution: 1) group DAN+ (diabetics with neuropathy); 2) group DAN- (diabetics without neuropathy); and 3) group CTRL (healthy control group). The patients underwent two-dimensional color-Doppler echocardiography and 12-lead electrocardiogram, 25 and 50 mm/s paper speed (gain 10 mm/mU). The QTc dispersion was determined as the difference between the maximum and the minimum value of the QTc interval in different leads of the ECG recording. QT interval was corrected (QTc) by heart rate according to the Bazett's formula. Cardiovascular autonomic function was evaluated by Ewing's tests (heart rate and blood pressure measurement during lying to standing, deep breathing, hand-grip isometric stress test and Valsalva's maneuver). RESULTS: QT dispersion was significantly greater (p < 0.01) in the patients with autonomic neuropathy (51 +/- 10 ms) than in the patients without autonomic neuropathy (29 +/- 6 ms) or in healthy control subjects (26 +/- 5 ms). CONCLUSIONS: Our data suggest that diabetic neuropathy, associated with an increased QT dispersion, shows a higher risk for serious ventricular arrhythmias and sudden cardiac death.

Problems in the evaluation of antihypertensive therapy using the trough/peak ratio.

In 1988, the U.S. Food and Drug Administration proposed guidelines for the clinical evaluation of new antihypertensive drugs. According to these guidelines, the drug effect at trough (measured as the difference in blood pressure values from placebo) should be no less than one half to two thirds of the peak effect. Unfortunately, calculation of the trough/peak ratio suffers the consequences of many methodological, interpretative, practical, and epidemiological problems. When taking readings at short time intervals, noninvasive ambulatory blood pressure monitoring allows evaluation of blood pressure variability by means of several statistical parameters. Blood pressure variability, measured as the standard deviation of the overall 24-hour blood pressure measurements, has been demonstrated to be significantly correlated with target-organ damage in hypertensive patients. Blood pressure variability may not change with long-acting antihypertensive agents, but it may increase with short-acting ones. Therefore, assessment of the trough/peak ratio may be overcome by the evaluation of drug-induced changes in the standard deviation of the mean 24-hour blood pressure.

Ambulatory blood pressure pattern in elderly athletes.

Indications with respect to parasympathetic nervous activity in vivo can be obtained only by means of indirect parameters. Ten elderly athletes were compared to 10 sedentary healthy peers, in order to evaluate blood pressure (BP) and heart rate (HR) circadian change and variability, as assessed by ambulatory 24-h non-invasive monitoring. Such comparison proved that the elderly athletes have a significantly lower value in: systolic 24-h BP; systolic and diastolic 24-h BP variability; systolic and diastolic day-time BP variability; systolic night-time BP variability; 24-h, day-time and night-time mean HR, as well as HR variability. Prolonged physical training improves, therefore, the parasympathetic control on the cardiovascular system in the elderly, which causes a low BP, HR, and a low related variability. Regular exercise induces a shift in the sympathetic: parasympathetic tone ratio towards a stronger parasympathetic influence. Such a neurovegetative tone seems to confer juvenile characteristics to the cardiovascular system of elderly athletes.

[Carditis associated with Mycoplasma pneumoniae infection. Clinical aspects and therapeutic problems]. / La cardite associata ad infezione da Mycoplasma pneumoniae. Peculiarità cliniche e problemi terapeutici.

A clinical case of carditis associated with Mycoplasma pneumoniae infection in a 65 year-old woman is reported in order to stress some clinical features and therapeutic problems; during a 5-year follow-up. On the basis of this experience it is possible to state that in the pathogenesis an autoimmune mechanism probably plays an important role, whereas in therapy specific antibiotics are not effective and a long-term treatment with anti-inflammatory drugs is necessary.

["White coat effect" on blood pressure]. / L'"effetto camice bianco" sulla pressioine arteriosa.

In the past few years non-invasive ambulatory blood pressure monitoring has become a widespread technology in the assessment of arterial hypertension. The "white coat effect" concept derives from comparison between "clinic" and "ambulatory" blood pressure. It consists of two opposite conditions: clinic hypertension with ambulatory normotension (the so-called "white coat hypertension") and clinic normotension with ambulatory hypertension (the so-called "white coat normotension"). Nearly 20% of unselected referred populations shows conditions that may not need medical treatment, such as the "white coat hypertensives", or that may need antihypertensive therapy, such as the "white coat normotensives".

White-coat normotension and blood pressure variability.

The objective of this study was to assess blood pressure variability in patients with clinical normotension and ambulatory hypertension (the so-called white-coat normotension). In 58 white-coat normotensives (mean age 64.2 +/- 14.9 years; male/female ratio = 1.5:1) the authors evaluated blood pressure variability using the twenty-four-hour coefficient of variability. Fifty-eight essential hypertensives with the same age and sex distribution were recruited as a control group. The coefficient of variability in white-coat normotension was greater than in the control group (14.8/16.1 +/- 4.2/3.8% vs 13.5/15.1 +/- 3.3/3.1%), but this difference was not statistically significant. These findings suggest that white-coat normotension is the result of a specific relaxing response to medical visits and not the expression of an elevated blood pressure variability. It is probably due to the reverse of the alerting response, which causes white-coat hypertension.

[Cardiovascular effects of autonomic neuropathy in insulin-dependent diabetes mellitus]. / Effetti cardiovascolari della neuropatia autonomica nel diabete mellito insulino-dipendente.

The present study was designed to evaluate whether autonomic diabetic neuropathy is a marker of severe cardiovascular disease. We recruited three groups of 12 patients each with the same age, sex and body weight distribution: Group DAN + (diabetics with neuropathy), Group DAN- (diabetics without neuropathy) and Group C (healthy control group). The patients underwent two-dimensional color Doppler echocardiography and maximal electrocardiographic exercise test by cycloergometer (multistage program with 25 W increments 3 min steps). Cardiovascular autonomic function was evaluated by Ewing's tests (heart rate and blood pressure measurement during lying to standing, deep breathing, handgrip isometric stress test and Valsalva manoeuvre). Heart rate and blood pressure proved to be significantly higher in the Group DAN+, than in the other groups, either at baseline or during stress test. Only 33% of DAN+ patients proved to reach 100 W during stress test, compared to 82% of DAN- and 87% of control subjects. No DAN+ patients reached 125 W, compared with 45% of DAN- and 58% of Group C patients. Echocardiographic examination showed normal left ventricular systolic function in all groups, without any significant difference in ventricular dimensions, and impaired left ventricular diastolic function in DAN+ patients, compared to Group C subjects (peak E 66.75 +/- 8.36 vs 73.49 +/- 12.53 cm/s; peak A 72.1 +/- 13.42 vs 59.75 +/- 13.26 cm/s; E/A 0.84 +/- 0.21 vs 1.38 +/- 0.15 and isovolumetric relaxation time 101 +/- 21 vs 70 +/- 17 ms). Our data suggest that diabetic autonomic neuropathy is a marker of reduced exercise tolerance and of diastolic left ventricular dysfunction.

Circadian changes of ambulatory blood pressure in an unselected population.

Ambulatory blood pressure monitoring does not interfere with the night-time blood pressure and heart rate reduction, typical haemodynamic effects of sleep. An unselected population of 186 subjects was split into quartiles by age to assess the age related changes in 24-h blood pressure profile. From ambulatory blood pressure monitoring data we calculated day-time and night-time blood pressure and heart rate average values, as well as their percent difference. Results show that there is no difference with regard to nocturnal heart rate reduction (on average, 15%) between age groups or sexes, whereas nocturnal blood pressure reduction (on average, 10%) is significantly lower in elderly males, but not females, when compared with young people. This flat 24-h blood pressure profile is associated with hypertension. Circadian changes of ambulatory blood pressure are very different in elderly hypertensive men and provide a marker of diffuse arterial damage.

[Effects of rehabilitation on cardiovascular autonomic function in ischemic cardiopathy]. / Effetti della riabilitazione sulla funzione autonomica cardiovascolare nella cardiopatia ischemica.

METHODS: Twenty patients with uncomplicated myocardial infarction randomized in two groups (group 1 and 2) of ten patients were investigated. Only group 1 trained four months according to a protocol of rehabilitation, whereas patients of group 2 followed their usual activity (control group). The autonomic cardiovascular function was estimated by Ewing's tests, that evaluate the variations of heart rate and blood pressure during deep breathing. RESULTS: Our data showed an increase of parasympathetic tone in group 1 (Valsalva ratio 1.55 +/- 0.28 vs 1.36 +/- 0.28, p < 0.01; variation in heart rate during deep breathing 17.3 +/- 4.6 vs 13.3 +/- 4.2). The sympathetic activity tests showed no significant difference after training. On the other hand, group 2 showed no significant difference in sympathetic and parasympathetic activity. CONCLUSIONS: In patients with uncomplicated myocardial infarction physical training increases the parasympathetic activity; as shown in the literature, such an increase can have clinical and prognostic importance, since improves cardiac performance and reduces the risk of sudden death from arrhythmic events.