Colorectal cancer patient-derived organoids and cell lines harboring ATRX and/or DAXX mutations lack Alternative Lengthening of Telomeres (ALT)

Telomere maintenance is necessary to maintain cancer cell unlimited viability. However, the mechanisms maintaining telomere length in colorectal cancer (CRC) have not been extensively investigated. Telomere maintenance mechanisms (TMM) include the re-expression of telomerase or alternative lengthening of telomeres (ALT). ALT is genetically associated with somatic alterations in alpha-thalassemia/mental retardation X-linked (ATRX) and death domain-associated protein (DAXX) genes. Cells displaying ALT present distinctive features including C-circles made of telomeric DNA, long and heterogenous telomeric tracts, and telomeric DNA co-localized with promyelocytic leukemia (PML) bodies forming so-called ALT-associated PML bodies (APBs). Here, we identified mutations in ATRX and/or DAXX genes in an extensive collection of CRC samples including 119 patient-derived organoids (PDOs) and 232 established CRC cell lines. C-circles measured in CRC PDOs and cell lines showed low levels overall. We also observed that CRC PDOs and cell lines did not display a significant accumulation of APBs or long telomeres with no appreciable differences between wild-type and mutated ATRX/DAXX samples. Overall, our extensive analyses indicate that CRC is not prone to engage ALT, even when carrying genetic lesions in ATRX and/or DAXX, and support the notion that ATRX/DAXX genomic footprints are not reliable predictors of ALT.

TGS1 mediates 2,2,7-trimethyl guanosine capping of the human telomerase RNA to direct telomerase dependent telomere maintenance

Pathways that direct the selection of the telomerase-dependent or recombination-based, alternative lengthening of telomere (ALT) maintenance pathway in cancer cells are poorly understood. Using human lung cancer cells and tumor organoids we show that formation of the 2,2,7-trimethylguanosine (TMG) cap structure at the human telomerase RNA 5′ end by the Trimethylguanosine Synthase 1 (TGS1) is central for recruiting telomerase to telomeres and engaging Cajal bodies in telomere maintenance. TGS1 depletion or inhibition by the natural nucleoside sinefungin impairs telomerase recruitment to telomeres leading to Exonuclease 1 mediated generation of telomere 3′ end protrusions that engage in RAD51-dependent, homology directed recombination and the activation of key features of the ALT pathway. This indicates a critical role for 2,2,7-TMG capping of the RNA component of human telomerase (hTR) in enforcing telomerase-dependent telomere maintenance to restrict the formation of telomeric substrates conductive to ALT. Our work introduces a targetable pathway of telomere maintenance that holds relevance for telomere-related diseases such as cancer and aging.

Telomerase protects chromosome ends in stem cells and cancer cells. Here the authors show that Trimethylguaonsine Synthase 1 (TGS-1) – dependent trimethylguanosine capping of the RNA component of the human telomerase complex has an important role in directing telomere dependent telomere maintenance and suppressing the ALT pathway in cancer cells.

Foraging strategies and physiological status of a marine top predator differ during breeding stages

Habitat characteristics determine the presence and distribution of trophic resources shaping seabirds' behavioural responses which may result in physiological consequences. Such physiological consequences in relation to foraging strategies of different life-history stages have been little studied in the wild. Thus, we aim to assess differences in oxidative status, condition (fat stores, i.e. triglyceride levels, TRI), stress (Heterophil/Lymphocyte (H/L) ratio), and leukocyte profiles between incubation and chick rearing highlighting the role of foraging strategies in a seabird (Calonectris diomedea). Chick rearing was more energetically demanding and stressful than incubation as demonstrated by high stress levels (H/L ratio and leukocytes) and lower body stores (assessed by TRI and the increment of weight) due to the high energy requirements of rearing chicks. Also, our results make reconsider the simplistic trade-off model where reproduction increases metabolism and consequently the rate of oxidative stress. In fact, high energy expenditure (VeDBA) during chick rearing was correlated with low levels of oxidative damage likely due to mechanisms at the level of mitochondrial inner membranes (uncoupling proteins or low levels of oxygen partial pressure). Further (more distant) and longer (more days) foraging trips were performed during incubation, when antioxidants showed low levels compared to chick rearing due to incubation fasting, a change in diet, or a combination of these factors; but unlikely because of oxidative shielding since no relation was found between oxidative damage and antioxidant capacity. Males showed higher numbers of monocytes which were positively correlated with antioxidant capacity compared to females, suggesting sexual differences in immune profiles. Species-specific costs and energetic demands of different breeding phases trigger behavioural and physiological adjustments.

Cancer-derived EVs show tropism for tissues at early stage of neoplastic transformation

From the past decade, extracellular vesicles (EVs) have attracted considerable attention as tools for the selective delivery of anti-neoplastic drugs to cancer tissues. Compared to other nanoparticles, EVs display interesting unique features including immune compatibility, low toxicity and the ability to encapsulate a large variety of small- and macro-molecules. However, in virtually all studies, investigations on EVs have been focused on fully transformed cancers: the possibility to apply EV technology also to early-stage tumors has never been explored.

Methods: Herein, we studied the ability of cancer-derived EVs to recognize and deliver their cargo also to incipient cancers. To this purpose, EV biodistribution was studied in MMTV-NeuT genetically modified mice during early mammary transformation, in fully developed breast tumors and in the normal gland of wild type syngeneic mice. EVs were loaded with indocyanine green (ICG), a near-infrared (NIR) dye together with oncolytic viruses and i.v. injected in mice. The nanoparticle biodistribution was assayed by in vivo and ex vivo optical imaging (detecting the ICG) and semiquantitative real-time PCR (measuring the adenoviral genome) in different tissues.

Results: Our results demonstrate the ability of cancer-derived EVs to recognize early-stage neoplastic tissues opening the possibility to selectively deliver theranostics also for tumor prevention.

Conclusions: Taken together our study demonstrates the ability of EVs to recognize and deliver diagnostic and therapeutic agents not only to fully transformed tissues but also to early stage tumors. These findings pave the way for the synthesis of “universal” EVs-based formulation for targeted cancer therapy.

Migrating birds avoid flying through fog and low clouds

Different weather conditions are known to affect bird migration, yet the influence of fog and low clouds on migrating birds has been rarely examined so far, and hence, their impact on bird movement is not well understood. Fog avoidance could be a consequence of visual limitations within the fog or may be the outcome of deteriorated soaring conditions due to the obstruction of the sun. We carried out a radar study at the Strait of Messina, which is a bottleneck for migrating birds traversing the Central Mediterranean Sea, to determine if the intensity of diurnal soaring bird migration was influenced by fog and other weather variables. We recorded bird movements using an X-band radar, which can detect birds flying within the fog, and recorded weather conditions using local meteorological observations. We examined if bird passage rate (number of tracks/hour) at the radar site was influenced by fog, wind speed and direction, air temperature and the time of day. Our findings suggest that fog was the most important factor affecting bird migration intensity as recorded by the radar, indicating that birds actively avoided flying into fog. In addition, wind direction affected bird migration intensity, with lower numbers recorded with southerly tailwinds and higher numbers recorded with westerly crosswinds. Our findings highlight a consequence of widespread meteorological conditions, and of fog in particular, on migrating birds, with implications for bird migration navigation, path length and flight energetics.

Interactions between commercial fishing vessels and a pelagic seabird in the southern Mediterranean Sea

BACKGROUND

Fishing activities can influence foraging behaviour of many seabird species worldwide. Seabirds are attracted by fishing vessels which can facilitate access to demersal fish as a novel food resource that otherwise would be unavailable. On the other hand, intense fishing activities cause depletion of fish stocks with a reduction of natural prey available for seabirds. Moreover, fisheries discards can have lower nutritional value than natural prey. However, the importance of fisheries discard for seabirds and the possible implications on their foraging ecology is still poorly understood. In this study, we analysed the interactions of Scopoli's shearwaters (Calonectris diomedea) during their foraging trips with fishing vessels. We combined the GPS and accelerometer data of shearwaters with the GPS data gathered during the same period from fishing vessels. Accelerometers allowed us to identify the main behaviours of birds.

RESULTS

The presence of fishing vessels significantly affected the individual behaviour of Scopoli's shearwaters. Birds increased the time spent sitting on the water within 1.28 ± 0.13 km of fishing vessels likely feeding or waiting for discards. Approaches towards vessels within the interaction distance were therefore classified as an interaction and were recorded in about 40% of individuals. Birds interacting with fisheries had longer flight time during their foraging trips and covered longer distances to reach more distant foraging areas compared with individuals not approaching vessels.

CONCLUSIONS

Our results suggested that fisheries discard consumption might not be a profitable source of food for Scopoli's shearwaters. Despite the high density of fishing vessels in the home range of Scopoli's shearwater, most individuals did not interact with them. Accordingly, scavenging individuals showed a lower foraging efficiency than their conspecifics. Intraspecific competition for foraging areas might play an important role for the foraging decision of birds to consume fisheries discards.

The laminA/NF-Y protein complex reveals an unknown transcriptional mechanism on cell proliferation

Lamin A is a component of the nuclear matrix that also controls proliferation by largely unknown mechanisms. NF-Y is a ubiquitous protein involved in cell proliferation composed of three subunits (-YA -YB -YC) all required for the DNA binding and transactivation activity. To get clues on new NF-Y partner(s) we performed a mass spectrometry screening of proteins that co-precipitate with the regulatory subunit of the complex, NF-YA. By this screening we identified lamin A as a novel putative NF-Y interactor. Co-immunoprecipitation experiments and confocal analysis confirmed the interaction between the two endogenous proteins. Interestingly, this association occurs on euchromatin regions, too. ChIP experiments demonstrate lamin A enrichment in several promoter regions of cell cycle related genes in a NF-Y dependent manner. Gain and loss of function experiments reveal that lamin A counteracts NF-Y transcriptional activity. Taking advantage of a recently generated transgenic reporter mouse, called MITO-Luc, in which an NF-Y–dependent promoter controls luciferase expression, we demonstrate that lamin A counteracts NF-Y transcriptional activity not only in culture cells but also in living animals. Altogether, our data demonstrate the occurrence of lamin A/NF-Y interaction and suggest a possible role of this protein complex in regulation of NF-Y function in cell proliferation.

Long-term survival of patients with critical limb ischemia treated with iloprost: response rate and predictive criteria. A retrospective analysis of 102 patients

OBJECTIVE

Critical limb ischemia (CLI) patients have poor long-term prognosis. We showed that iloprost improves outcomes (major amputation and survival) up a 5-year follow-up, but it is not known if in this length of time the survival curves, of clinical responders and non-responders, differ.

PATIENTS AND METHODS

A retrospective study enrolling 102 consecutive patients between 2004-2008, with clinical and instrumental (ultrasound, angiography, transcutaneous tensiometry of oxygen TcpO2 and carbon dioxide TcpCO2 in the affected and contralateral limbs) diagnosis of critical ischemia. All patients received the best medical therapy. Iloprost was administered (0.5-2 ng/kg/min 6 hours/day for 2-4 weeks) in all patients initially considered unsuitable for revascularization, repeating it regularly in time every six-twelve months in the case of positive response. The minimum expected follow-up was 4 years.

RESULTS

71.5% of patients were treated with iloprost and the responder rate was 71.2%. Most of the patients were regularly retreated with repeated cycles. Initial median supine TcpCO2 in symptomatic limb was higher in untreated patients than those treated (58 vs. 49 mmHg; p < 0.05) and in non-responders compared to responders (60 vs. 49 mmHg; p < 0.05). TcpCO2 directly and significantly correlated with the highest risk of mortality and seems to represent a new accurate prognostic criterion of unfavourable short and long-term response to prostanoid. In iloprost group, major amputations were significantly reduced. Revascularization was significantly higher in non-responders (57.1% vs. 11.5%; p < 0.05). There was a significantly higher prevalence of subsequent myocardial infarction in the non-iloprost group (27.6% vs. 9.6%; p < 0.05). The survival rate of non-responders was higher than untreated up until the second year (76.2% vs. 62%; p < 0.05). At 4 years we found higher survival in patients treated with iloprost (64.3% vs. 41% in untreated; p < 0.05) and in responders (75% vs. 38.1% in non-responders; p < 0.05).

CONCLUSIONS

Our results confirm the favourable role of iloprost on the long-term outcome in patients with CLI. In particular, the maximum benefit is obtained in responder patients treated with multiple cycles of infusion.

Transcutaneous Oxygen and Carbon Dioxide Measurement in Peripheral Vascular Disease

Combined transcutaneous oxygen tension (tcPO2) and transcutaneous carbon dioxide tension (tcPCo2) measurements were carried out at both the subclavicular and metatarsal level in 29 controls and 100 patients with peripheral arterial obstructive disease (PAOD) (intermittent claudication: n = 40, critical limb ischemia: n = 60). Interindividual variation coefficients of arterial and subclavicular tcPCO2 (n = 94 subjects) were superimposable, while tcPo2 variability was twice the arterial value. Furthermore, arterial tensions were better predicted by tcPCO2 than by tcPO2 measurement. In the 75 limbs with an ABI < 0.9 of patients with intermittent claudication, tcPCO2 did not differ significantly from controls (n = 58 limbs), but it was elevated in those with critical limb ischemia (n = 74 limbs), although control and pathological values overlapped widely even in this latter group. At variance with tcPCO2, tcPQ2 was lower in intermittent claudication than in controls, and undetectable in most of the symptomatic limbs with critical ischemia, irrespective of concomitant diabetes. In the overall sample (n = 255 limbs), tcPCO2 did not show significant changes for tcPo2 values ranging from 80 to 10 mmHg, and it increased markedly in several—but not all—patients whose tcPo2 values were below that limit.

To evaluate further the biological significance of an increase in tissue tcPCO2, another sample of 24 subjects underwent acute forearm ischemia for a period of thirteen minutes, a maneuver that increased tcPCO2 markedly, indicating that this parameter is indeed a correlate of drastic reductions in limb perfusion. Thus, tcPCO2 is methodologically less variable than tcPo2 and more predictive of arterial values. However, the wide overlap with control values restrains its use as an isolated diagnostic tool to substantiate PAOD, even in the most advanced stages of disease. Marked elevations in tCPCO2 can be found in patients with critical limb ischemia, although normal values may coexist with low or negligible tcPO2 levels for reasons to be clarified. Further work is needed to establish the extent to which tcPcO2 determination may complement tcPO2 to differentiate extreme from less severe degrees of critical limb ischemia.

Chlorthalidone Improves Endothelial-Mediated Vascular Responses in Hypertension Complicated by Nondiabetic Metabolic Syndrome

Background: The study was conducted to evaluate the vascular effects of chlorthalidone, a distal tubule-acting natriuretic agent, in hypertensive patients with nondiabetic metabolic syndrome, an insulin-resistant condition characterized by endothelial dysfunction and high risk for diabetes mellitus development.

Methods: Thirteen untreated hypertensive patients with Adult Treatment Panel-III-defined nondiabetic metabolic syndrome were assigned to 3-month treatment with chlorthalidone. The end-points were baseline and post-treatment evaluation of (1) forearm blood flow (strain-gauge plethysmography) responses to graded intra-arterial acetylcholine infusion to test endothelial-mediated vasomotor function, with sodium nitroprusside as a control for endothelium-independent vasodilatation; (2) minimum forearm vascular resistance, the ratio of mean blood pressure and maximal blood flow in response to 13-minute arterial occlusion, as a hemodynamic correlate of arteriolar structure; and (3) transcapillary albumin escape rate (the 1-hour decay rate of 125I-albumin, 6-8 μC ev) as a measure of systemic capillary permeability. Additional measurements included baseline and posttreatment lipids, fasting, and postload glucose and insulin as well as the homeostasis model assessment, an index of insulin sensitivity.

Results: Chlorthalidone reduced blood pressure, augmented acetylcholine-mediated vasodilatation, decreased minimum forearm resistance, and slowed the transcapillary albumin escape rate. Metabolic parameters did not change significantly except for an increase in low-density lipoprotein cholesterol levels.

Conclusions: Chlorthalidone improved endothelial function, reversed abnormal arteriolar structure, and slowed albumin permeation in hypertensive patients with nondiabetic metabolic syndrome.

Long-term clinical outcomes in critical limb ischemia--A retrospective study of 181 patients

OBJECTIVE

Critical limb ischemia (CLI) is the most severe manifestation of the peripheral arterial disease. To date, several prognostic factors have been identified but the data of long-term follow-up in real life setting are scarce. The aim of our study is to describe a large group of CLI patients and identify possible prognostic factors, in a long-term follow-up.

PATIENTS AND METHODS

Case-control, retrospective study. 181 consecutive CLI patients with a minimum follow-up of 5 years were included in the study.

RESULTS

Overall mortality was 15%, 24%, and 43% at 1, 2, and 5 years, respectively. Among known risk factors, only arterial hypertension was significantly correlated with survival rate; no differences were found between diabetics and non-diabetics. Patients treated with intravenous iloprost (46%), compared to untreated patients, showed a better (p < 0.0001) long-term outcome in terms of major amputation (6% vs. 21%), subsequent vascular surgery (4% vs. 32%) and survival rates (69% vs. 47%), at 5-year follow-up. Major amputations were significantly correlated with lower median forefoot transcutaneous values of O2 (0/3 mmHg, p < 0.001) and higher median values of CO2 (83/53 mmHg, p < 0.0001) in supine/dependent position, respectively.

CONCLUSIONS

Our results confirm the poor prognosis of CLI patients in a very long-term follow-up and the severe metabolic damage caused by ischemia. A favourable role of iloprost was observed, in agreement with previous evidence in the literature.

Health care delivery in type 2 diabetes. A survey in an Italian primary care practice

AIMS

Evidence-based guidelines provide targets and performance measures for the treatment of type 2 diabetic patients but a wide gap separates guidelines-driven recommendations from their clinical application, a phenomenon hindering the transfer of proven benefits to affected populations.

METHODS

We analyzed the quality of diabetic care delivered by 8 general practitioners joint in a group practice attending 571 diabetic patients (5.6% of the total enlisted subjects) by assessing process (% of HbA1c, SBP and LDL-C determinations) and intermediate outcome (% of patients with HbA1c <7% vs >8%, systolic BP <130 mmHg vs >140 mmHg, LDL-cholesterol <100 mg/dL vs >130 mg/dL) indicators.

RESULTS

HbA1c was at target in 49% of patients and >8% in 22%; SBP and LDL-C determination was available in about two-thirds of patients, only a minority at target for SBP and LDL-C. Antihyperglycemic and antihypertensive treatment was prescribed in most patients but only a third was on statins. During the post-evaluation phase, percentages of patients with HbA1c >8%, SBP < 130 mmHg and LDL-C < 100 mg/dL and the drug prescription pattern did not change.

CONCLUSIONS

Several weaknesses affect primary care delivery to type 2 diabetic patients and efforts are needed to improve the management of this high-risk group.

Q192R Paraoxonase (PON)1 Polymorphism, Insulin Sensitivity, and Endothelial Function in Essential Hypertensive Men

AIMS

Essential hypertension is characterized by increased reactive oxygen species (ROS) generation harmful for insulin sensitivity and nitric oxide (NO)-mediated vasomotor function, a noxious effect that paraoxonase (PON)1, an antioxidant circulating high-density lipoprotein (HDL)-bound esterase, may counteract. The PON1 gene contains several polymorphisms including a glutamine (Q) to arginine (R) transition at position 192 encoding circulating allozymes with higher antioxidant activity that might influence both parameters.

METHODS

Q192R was determined by polymerase chain reaction in 72 never-treated, glucose-tolerant, uncomplicated essential hypertensive men. Insulin sensitivity was assessed by homeostasis model assessment (HOMA) and endothelial function by forearm vasodilation (strain-gage venous plethysmography) to intra-arterial acetylcholine (ACH) with sodium nitroprusside (NIP) as a NO-independent control. Additional evaluation variables included 24-hour blood pressure (BP), lipids, BMI, smoking status, and metabolic syndrome (MetS) by Adult Treatment Panel (ATP)-III criteria. R192 was considered as the rare allele, and its associations analyzed by dominant models (Q/Q vs. Q/R + R/R).

RESULTS

Genotype frequencies were consistent with the Hardy–Weinberg equilibrium. HOMA was lower and insulin resistance (the upper fourth of HOMA values distribution) less prevalent in Q/R + R/R carriers in whom ACH-mediated vasodilatation was greater and endothelial dysfunction (the bottom fourth of ACH^AUC values distribution) less frequent than in Q/Q homozygotes. Q192R polymorphism and MetS were unrelated parameters despite their common association with insulin resistance. 24-hour BP, BMI, lipids, and smoking habits were homogeneously distributed across genotypes.

CONCLUSIONS

Q192R polymorphism associates differentially with insulin sensitivity and endothelial function in essential hypertensive men.

Testing cognitive navigation in unknown territories: homing pigeons choose different targets

Homing pigeons (Columba livia) are believed to adopt a map-and-compass strategy to find their way home. Surprisingly, to date a clear demonstration of the use of a cognitive map in free-flight experiments is missing. In this study, we investigated whether homing pigeons use a mental map in which – at an unknown release site – their own position, the home loft and a food loft are represented simultaneously. In order to test this, homing pigeons were trained to fly to a 25–30 km distant food loft. A total of 131 hungry and satiated pigeons were then released from an unfamiliar site equidistant from the food loft and the home loft. Their vanishing bearings and homing times were assessed conventionally at four sites, and also their flight tracks from one release site by means of GPS loggers. The vanishing bearings of fed and hungry birds differed significantly at all release sites and a highly significant proportion of hungry birds flew to the food loft, while the fed birds headed home. The GPS experiment revealed a number of pigeons flying very precisely to the food loft, others correcting their flight direction after topography-induced detours. This implies that the pigeons knew their geographical position in relation to the targets, and chose a flight direction according to their locally manipulated needs – clearly the essence of a cognitive navigational map.

Lack of a relationship between circulating gamma-glutamyltransferase levels and carotid intima media thickness in hypertensive and diabetic patients

BACKGROUND

By increasing the intracellular prooxidant burden, gamma-glutamyltransferase (GGT) may accelerate atherosclerotic vascular disease. That noxious influence may be reflected by circulating enzyme levels, a correlate of cardiovascular risk factors, and a predictor of incident events. To evaluate this hypothesis, we tested the association between circulating GGT and common carotid intima-media thickness (CIMT), a surrogate index of systemic atherosclerotic involvement, in a large and well-characterized group of patients at risk of cardiovascular disease (CVD).

PATIENTS

This study analyzed 548 patients with hypertension and/or diabetes and a widely prevalent history of CVD. Subjects with known hepatic disease and abnormal GGT values were excluded.

METHODS

CIMT (B-mode ultrasonography) values were the mean of four far-wall measurements at both common carotids. Metabolic syndrome (MetS) was diagnosed according to National Cholesterol Education Program-Adult Treatment Panel III criteria. Due to inherent sex-related differences in GGT levels, the data were analyzed separately in males and females in samples dichotomized by the median.

RESULTS

The age-adjusted CIMT values did not differ by GGT levels in males or females. In contrast, the carotid wall was consistently thicker in patients with a history of CVD and MetS independent of age and concurrent GGT values. In both sexes, GGT was associated with key components of the MetS such as triglycerides, fasting plasma glucose, and body mass index.

CONCLUSION

The data collected in this mixed group of hypertensive and/or diabetic patients with widely prevalent history of CVD do not support the concept of a direct pathophysiological link between GGT levels within reference limits and atherosclerotic involvement.

Early left ventricular mechanics abnormalities in prehypertension: a two-dimensional strain echocardiography study

BACKGROUND

Prehypertension predicts established hypertension. In this study, the aim was to analyze left ventricular (LV) mechanics in borderline prehypertensive (pre-HT) and hypertensive (HT) subjects through two-dimensional (2D)-strain echocardiography and then evaluate possible relations between cardiac parameters and insulin metabolism (homeostasis model assessment of insulin resistance (HOMA(IR)).

METHODS

Seventy-four consecutive newly diagnosed, untreated HT were divided, on the basis of their office blood pressure (BP) measurements, confirmed by ambulatory BP monitoring (ABPM), in 41 borderline pre-HT (ABPM: 122.5 +/- 6.7/76.2 +/- 5.2 mm Hg) and 33 never-treated mild HT (ABPM: 138.3 +/- 7.3/87.6 +/- 7.1 mm Hg). Thirty-three healthy normotensive (NT) controls (ABPM: 114.8 +/- 6.3/73.1 +/- 6.1 mm Hg) (P < 0.0001) were also studied (NT). All subjects performed 2D color Doppler and pulsed-wave tissue Doppler imaging (PW-TDI).

RESULTS

Left ventricular mass (LVM) was significantly higher in pre-HT (39.2 +/- 8.7 g/m(2.7)) and in HT (43.6 +/- 8.5 g/m(2.7)) compared with NT (30.9 +/- 7.4 g/m(2.7)) (P < 0.0001). A mild LV diastolic dysfunction was found both with Doppler mitral flow velocity and PW-TDI at mitral annulus level analysis. Longitudinal 2D strain in pre-HT (-18.9% +/- 3.4) and in HT (-18.0% +/- 3.3) was significantly lower than in NT (-23.9% +/- 3.0) (P < 0.002). These LV abnormalities were associated with systolic ABPM, LVM, and HOMA(IR).

CONCLUSIONS

Early abnormalities of LV longitudinal systolic deformation were found both in pre-HT and HT, together with a mild LV diastolic dysfunction. In both groups this early cardiac systolic and diastolic dysfunction is associated to insulin resistance, systolic pressure load, and cardiac remodeling.

The effect of angiotensin receptor blockers on C-reactive protein and other circulating inflammatory indices in man

Anti-inflammatory properties may contribute to the pharmacological effects of angiotensin II receptor blockers (ARBs), a leading therapeutic class in the management of hypertension and related cardiovascular and renal diseases. That possibility, supported by consistent evidence from in-vitro and animal studies showing pro-inflammatory properties of angiotensin II, has been evaluated clinically by measuring the effect of ARBs on C-reactive protein and other circulating indices of inflammation (e-selectin, adhesion molecules, interleukin-6, tissue necrosis factor-alpha, monocyte chemoattractant protein-1) of potential clinical relevance, a body of evidence that this paper aims to review.

Lack of association between TGF-beta-1 genotypes and microalbuminuria in essential hypertensive men

BACKGROUND

Polymorphisms within the gene for transforming growth factor (TGF)-beta-1, a pro-fibrogenic cytokine pathophysiologically involved in hypertension and hypertensive target damage, might modulate the biological activity of the encoded protein. Through that mechanism, they might contribute to microalbuminuria, a marker of subclinical renal damage and a correlate of systemic inflammation and endothelial dysfunction in hypertension, a possibility never before tested. For this reason, we assessed the association of four TGF-beta-1 polymorphic variants (C-509T, Leu(10)-->Pro, Arg(25)-->Pro, Thr(263)-->Ile) with albuminuria in uncomplicated essential hypertensive men, using (circulating active + acid-activatable latent) TGF-beta-1 levels as an indirect index of their in vivo biological activity. Because of the close pathophysiological link of TGF-beta-1 with the renin-angiotensin system, we also tested the behaviour of the angiotensin converting enzyme (ACE) deletion/insertion (D/I) polymorphism.

METHODS

Albuminuria (three overnight collections), office and 24-h BP, left ventricular mass index (LVMI), BMI, renal function, glucose, lipids, plasma TGF-beta-1 (n = 162, ELISA) were measured in 222 genetically unrelated, never-treated, uncomplicated Caucasian hypertensive men. ACE D/I polymorphisms were analysed by the polymerase chain reaction technique or a 5' nuclease assay with further restriction analysis when required.

RESULTS

Urine albumin levels or microalbuminuria (albuminuria > or =15 microg/min) did not differ by TGF-beta-1 genotypes, but both parameters were more frequent in ACE D/D homozygotes. Plasma TGF-beta-1 was similar across genetic backgrounds and was unrelated to albuminuria. Cardiovascular, renal, metabolic parameters were homogeneously distributed across genotypes.

CONCLUSIONS

In contrast to its link with the ACE D/I genotype, microalbuminuria was independent of TGF-beta-1 polymorphism in this group of never-treated, uncomplicated essential hypertensive men.

Dysglycaemia in non-diabetic hypertensive patients: comparison of the impact of two different classifications of impaired fasting glucose on the cardiovascular risk profile

The clinical correlates and risk profile of prediabetes (fasting plasma glucose (FPG) values in the upper normal limits but below the diabetic threshold) in hypertension, an insulin-resistant, prodiabetogenic condition, are scarcely known. For this reason, we evaluated 982 non-diabetic (FPG,<126 mg 100 ml(-1) and no antidiabetic treatment) referred hypertensive patients without a history of cardiovascular disease grouped by mild (100-109 mg 100 ml(-1)) and advanced (110-125 mg 100 ml(-1)) dysglycaemia compared with normal FPG (<100 mg 100 ml(-1)). FPG, total and high density lipoprotein (HDL) cholesterol, triglycerides and total white blood cell count were assessed by standard methodologies; 10-year predicted coronary heart disease (CHD) risk was approximated by the Framingham risk score (FRS). Metabolic syndrome (MetS) was diagnosed by standard categorical criteria using either 110 or 100 mg 100 ml(-1) as a threshold for impaired fasting glucose (IFG). FPG was above 110 in 13% and between 100 and 109 in 20% of patients. In both dysglycaemic groups, perturbed glucose homeostasis was associated with abnormally high fasting triglycerides, low HDL cholesterol, obesity, worse CHD risk profile and higher white blood cell count. MetS was highly prevalent and its distribution pattern was markedly influenced by the definitions of IFG based on different FPG cutoffs. Thus, even mildly perturbed glucose homeostasis associates with atherogenic dyslipidaemia, obesity and adverse risk profile in non-diabetic hypertensive patients. Because of its prediabetic nature, dysglycaemia should prompt measures to prevent new-onset diabetes, although the role of IFG as an independent risk factor awaits specifically designed intervention trials.

Doxazosin in metabolically complicated hypertension

Metabolic syndrome, a cluster of metabolic abnormalities with visceral obesity and insulin resistance as its central component, is highly prevalent among hypertensive patients. Hypertension complicated by metabolic syndrome is associated with an increased risk of cardiovascular disease and new-onset Type II diabetes mellitus that further aggravates the prognostic outlook. Such a complex condition requires a multifactorial intervention including blood pressure lowering, improvement of the adverse metabolic profile and delayed onset of new diabetes. In this respect, doxazosin and other alpha-1 adrenoceptor blocking agents are of interest given their effect on the lipid profile in dyslipidemic, obese hypertensive patients, either diabetic or not. Doxazosin improves insulin sensitivity, apparently by accelerating insulin and glucose disposal through vasodilatation of skeletal muscle vascular beds. Whether long-term treatment with the drug might delay, or possibly prevent, incident Type II diabetes in hypertension complicated by metabolic syndrome is an intriguing possibility to be tested in appropriately designed clinical trials.

Lack of association between endothelial nitric oxide synthase gene polymorphisms, microalbuminuria and endothelial dysfunction in hypertensive men

BACKGROUND

The Glu298Asp, T786C and 4a/4b genetic polymorphisms within the endothelial nitric oxide synthase (e-NOS) gene may predispose to hypertension, ischaemic heart disease and renal damage, possibly by reducing the generation of nitric oxide (NO), a fundamental substance in renal and cardiovascular biology. That same mechanism may contribute to raise albuminuria, a correlate of endothelial dysfunction and a marker of early kidney damage and poor cardiovascular prognosis in patients with hypertension. To assess that hypothesis, we evaluated the association of albuminuria with eNOS genotypes and their interacting potential with the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism. We also tested their impact on systemic NO availability, as reflected by endothelial-mediated forearm vasodilatation.

METHODS

Albuminuria (three overnight collections), blood pressure, body mass index, renal function, glucose, lipids and prevalence of the metabolic syndrome were measured in 235 genetically unrelated, never-treated, uncomplicated white men with essential hypertension. Endothelial function was assessed in a patient subgroup (n = 94) by measuring plethysmographic forearm blood flow vasodilatation in response to intra-arterial acetylcholine with sodium nitroprusside as a control. Polymerase chain reaction or a 5' nuclease assay were used to characterize the eNOS and ACE I/D variants.

RESULTS

Albuminuria or microalbuminuria (albuminuria > or = 15 microg/min) showed no association with eNOS polymorphisms either per se or after accounting for the co-existing ACE I/D genetic configuration. Forearm responses to acetylcholine did not differ by eNOS polymorphisms. Cardiovascular, renal, metabolic parameters were homogeneously distributed across different genetic backgrounds.

CONCLUSION

eNOS polymorphisms apparently play no role in promoting hypertensive renal damage, and do not influence endothelial-mediated vasodilatation in never-treated men with essential hypertension.

α-Adducin and angiotensin-converting enzyme polymorphisms in hypertension: evidence for a joint influence on albuminuria

BACKGROUND

A single-nucleotide polymorphism (Gly460Trp) within the alpha-adducin gene (ADD1) may influence several renal phenotypes, including salt sensitivity, susceptibility to renal failure, the renal haemodynamics and confer a worse cardiovascular risks profile. However, its relationship with microalbuminuria, a marker of early renal and cardiovascular damage and an independent predictor of morbid events in hypertension, is unknown. For this reason, we related the ADD1 genetic polymorphism to urine albumin levels and other clinical variables in essential hypertensive men. The angiotensin-converting enzyme (ACE) insertion/deletion (ID) polymorphism was also evaluated because of its interactive potential with the ADD1 genotype.

METHODS

Albuminuria (three overnight collections), echocardiographic left ventricular mass index, blood pressure, body mass index, renal function, glucose and lipids were measured in 238 genetically unrelated, never treated, uncomplicated Caucasian essential hypertensive men. Polymerase chain reaction or a 5' nuclease assay were used to characterize the ACE ID and ADD1 Gly460Trp variants, respectively.

RESULTS

Microalbuminuria (albuminuria >or= 15 microg/min) was more frequent in patients with the ACE DD variant, but only in those with a ADD1 Gly460Gly background. In contrast, urine albumin did not differ by ACE ID genotype in the presence of mutated ADD1 Trp alleles. ADD1 polymorphisms per se were not associated with albuminuria. Cardiovascular, renal, metabolic parameters were homogeneously distributed among different genetic backgrounds.

CONCLUSIONS

ACE DD and ADD1 Gly460Gly polymorphisms may jointly influence albuminuria in hypertensive men, 460Gly homozygosis facilitating or, possibly, the 460Trp allele mitigating the noxious renal impact of the ACE DD genotype. The data highlight further the complex pathophysiological implications of microalbuminuria in hypertension.

Orientation in the wandering albatross: interfering with magnetic perception does not affect orientation performance

After making foraging flights of several thousands of kilometers, wandering albatrosses (Diomedea exulans) are able to pinpoint a specific remote island where their nests are located. This impressive navigation ability is highly precise but its nature is mysterious. Here we examined whether albatrosses rely on the perception of the Earth's magnetic field to accomplish this task. We disturbed the perception of the magnetic field using mobile magnets glued to the head of nine albatrosses and compared their performances with those of 11 control birds. We then used satellite telemetry to monitor their behavior. We found that the ability of birds to home specific nest sites was unimpaired by this manipulation. In particular, experimental and control birds did not show significant differences with respect to either foraging trip duration, or length, or with respect to homing straightness index. Our data suggest that wandering albatrosses do not require magnetic cues to navigate back to their nesting birds.

The vascular effects of doxazosin in hypertension complicated by metabolic syndrome

AIMS

To evaluate the vascular effects of doxazosin, an alpha-1 antagonist, in hypertensive patients with metabolic syndrome in whom the drug has previously been shown to exert beneficial metabolic actions on lipids and insulin metabolism.

EXPERIMENTAL PROTOCOL

Twelve untreated non-diabetic hypertensive patients with National Cholesterol Education Program (NCEP) ATP-III defined metabolic syndrome were assigned to three-months of treatment with doxazosin (5.5 +/- 1.9 mg/die). Study variables were measured at baseline and after treatment. End-points: forearm blood flow (strain-gauge plethysmography) responses to graded intra-arterial acetylcholine and sodium nitroprusside infusion to test endothelium-dependent and independent vasodilatation respectively. Minimum forearm vascular resistance, the ratio of mean blood pressure and post-ischaemic maximal blood flow, as an index of arteriolar structure; transcapillary albumin escape rate (the 1-h decay rate of I-albumin, 6-8 microC ev) as a measure of systemic capillary permeability. Lipids, fasting and post-glucose insulin were measured at baseline and after treatment.

RESULTS

Doxazosin reduced blood pressure, augmented acetylcholine-mediated vasodilatation, decreased minimum resistance and, although not to a statistically significant extent, transvascular albumin leakage increased high-density lipoprotein (HDL) cholesterol while triglycerides and post-stimulative hyperinsulinemia decreased.

CONCLUSIONS

Doxazosin improved endothelial-mediated vasomotor function and reversed abnormal arteriolar structure in hypertensive patients with metabolic syndrome while improving lipid profile and blunting post-glucose hyperinsulinemia.

LDL cholesterol and global risk stratification in referred hypertensive patients

BACKGROUND

Global risk status more than BP values per se drive nowadays treatment decisions and increasing emphasis is given to the role of lipid control in hypertension (HT). However, the distribution of circulating low density lipoproteins (LDL) levels as a function of risk profile and lipid-lowering treatment in hypertensive patients is unclear.

METHODS

We analysed 1196 patients (677 males, age range: 20-80 years) referred to our Hypertension Unit with treatment history and a complete dataset (systolic blood pressure levels, being on anti-hypertensive treatment or not, total and high density lipoproteins (HDL) cholesterol, smoking status, sex, age) for 10-year absolute coronary heart disease (CHD) risk stratification by National Cholesterol Education Program (NCEP)/ATP III guidelines. LDL cholesterol <25.9 mmol/L (100 mg/dL) was the target for high-risk patients (vascular diseases, diabetes, hypertension with multiple risk factors at CHD risk >20%/10 years). LDL <33.6 mmol/L (130 mg/dL) and 41.4 mmol/L (160 mg/dL) were the thresholds for intermediate (10-20%/10 years) and low (<10%/10 years) CHD risk.

RESULTS

At referral, 78% of high-risk patients were above target LDL and, overall, 56% had LDL cholesterol above the desired risk-specific thresholds. Lipid-lowering treatment was prescribed in 19% in whom LDL was actually higher than the untreated group.

CONCLUSIONS

LDL cholesterol was out of target in most of a large series of referred high-risk hypertensive patients and LDL levels were largely unsatisfactory even in those undergoing lipid-lowering treatment. The data show the intensive effort still needed to implement global risk-oriented prevention strategies in hypertensive populations.

Insulin resistance causes impaired vasodilation and hypofibrinolysis in young women with polycystic ovary syndrome

INTRODUCTION

Insulin resistance, a novel cardiovascular risk factor, is often associated with increased plasminogen activator inhibitor-1 levels and impaired vasodilation. Insulin infusion in the forearm induces plasminogen activator inhibitor-1 and tissue plasminogen activator expression and endothelium-dependent vasodilation in normal subjects. The present study explores the relationship between insulin-induced vasodilatory and fibrinolytic properties of the endothelium in women with polycystic ovary syndrome, frequently affected by insulin resistance and early atherosclerosis.

MATERIALS AND METHODS

Metabolic, hormonal and fibrinolytic parameters were evaluated in 64 patients with polycystic ovary syndrome (19 insulin-resistant and 45 insulin-sensitive) and in 25 controls. In 16 women with polycystic ovary syndrome, 8 insulin-resistant and 8 insulin-sensitive, blood flow, plasminogen activator inhibitor-1 and tissue plasminogen activator expression were evaluated during insulin infusion into the forearm.

RESULTS

Elevated basal plasminogen activator inhibitor-1 levels were found in women with polycystic ovary syndrome, correlating directly with insulin levels. Plasminogen activator inhibitor-1 expression increased during insulin infusion in all women with polycystic ovary syndrome, but was delayed and sustained in insulin-resistant patients (p<0.01). Vasodilatory response to insulin was blunted (p<0.01) and tissue plasminogen activator expression abolished in insulin-resistant patients (p<0.01).

CONCLUSION

Our study demonstrates that women with polycystic ovary syndrome and insulin resistance show a blunted endothelial-dependent vasodilation. The impaired endothelial release of tissue-plasminogen activator and the sustained plasminogen activator inhibitor-1 release during insulin infusion suggest a hypofibrinolytic state in PCOS patients with insulin resistance. This hemodynamic and fibrinolytic derangement may contribute to the pathogenesis of early atherosclerosis in insulin resistance.

Role of a neuronal small non-messenger RNA: behavioural alterations in BC1 RNA-deleted mice

BC1 RNA is a small non-messenger RNA common in dendritic microdomains of neurons in rodents. In order to investigate its possible role in learning and behaviour, we compared controls and knockout mice from three independent founder lines established from separate embryonic stem cells. Mutant mice were healthy with normal brain morphology and appeared to have no neurological deficits. A series of tests for exploration and spatial memory was carried out in three different laboratories. The tests were chosen as to ensure that different aspects of spatial memory and exploration could be separated and that possible effects of confounding variables could be minimised. Exploration was studied in a barrier test, in an open-field test, and in an elevated plus-maze test. Spatial memory was investigated in a Barnes maze and in a Morris water maze (memory for a single location), in a multiple T-maze and in a complex alley maze (route learning), and in a radial maze (working memory). In addition to these laboratory tasks, exploratory behaviour and spatial memory were assessed under semi-naturalistic conditions in a large outdoor pen. The combined results indicate that BC1 RNA-deficient animals show behavioural changes best interpreted in terms of reduced exploration and increased anxiety. In contrast, spatial memory was not affected. In the outdoor pen, the survival rates of BC1-depleted mice were lower than in controls. Thus, we conclude that the neuron-specific non-messenger BC1 RNA contributes to the aptive modulation of behaviour.

Low-grade inflammation and microalbuminuria in hypertension

Background- Albuminuria and C-reactive protein (CRP), a marker of systemic low-grade inflammation, are frequently elevated in essential hypertension and predict cardiovascular prognosis independent of conventional risk factors. However, in spite of their potentially important links, the interrelationships between the 2 parameters have not been explored in depth in hypertensive patients.

METHODS AND RESULTS

Albuminuria (the mean of 3 overnight urine collections), high-sensitive CRP (hs-CRP), 24-hour blood pressure (BP), weight, lipids, poststimulative (75 g PO) plasma glucose, insulin, and insulin sensitivity by the homeostasis model assessment model were evaluated in 220 never treated, nondiabetic, uncomplicated essential hypertensive men. Albuminuria > or =15 microg/min was defined as microalbuminuria and hs-CRP values above and below median (2.3 mg/L) as high and low, respectively. Concentric left ventricular hypertrophy was diagnosed by echocardiography, and a full-blown metabolic syndrome was identified in presence of hypertension and at least 3 of following: obesity, subclinical hyperglycemia, low high-density lipoprotein (HDL) and high triglycerides. Microalbuminuria was present in 54 patients, 29 with high hs-CRP characterized by higher 24-hour systolic BP, postload glucose, body mass index, lower HDL cholesterol, more frequent metabolic syndrome, concentric LVH, and active smoking than those with either isolated microalbuminuria (n=27) or normoalbuminuria.

CONCLUSIONS

Microalbuminuria accompanied by evidence of subclinical inflammation is a strong correlate of metabolic abnormalities in essential hypertension and identifies a patient subset at very high cardiovascular risk. In contrast, isolated microalbuminuria may represent a distinct pathophysiological condition characterized by a more benign profile and possibly a better prognosis.

Early impairment of myocardial blood flow reserve in men with essential hypertension: A quantitative myocardial contrast echocardiography study

OBJECTIVE

Aims of this study were to: (1) demonstrate whether quantitative myocardial contrast echocardiography could detect an index of myocardial blood flow reserve through the analysis of refilling curves generated by microbubble transit into myocardium both at rest and after vasodilatation induced by dipyridamole; and (2) explore with this method myocardial microcirculatory function in two different models (ie, patients with essential hypertension and control subjects).

METHODS

Two groups of strictly age-matched men were studied (case-control study): 12 patients who were adults (28.2 +/- 0.2 years) and asymptomatic with never-treated essential hypertension, a mild degree of left ventricular hypertrophy, and normal left ventricular function; and 12 control subjects. Quantitative myocardial contrast echocardiography was performed in all study participants. We used second-generation ultrasound microbubbles as echocardiography contrast agent. Real-time color-coded power modulation was performed with a phased-array system interfaced to a S3 transducer (1.3-3.6 MHz).

RESULTS

In control subjects there was little increase in myocardial blood volume (30%) between basal and hyperemic status (P <.05); in patients with hypertension this parameter increased by 22% (P <.05). Myocardial blood velocity increased after dipyridamole by 270% in control subjects (P <.01), whereas for patients with hypertension this parameter increased only by 150% (P <.02). The index of myocardial blood flow reserve was significantly lower for patients with hypertension than in control subjects (3.3 +/- 0.3 vs 4.4 +/- 0.3, respectively; P <.01).

CONCLUSION

Results of our study documented that myocardial microcirculation in young adult patients with hypertension showed an early impairment in the vasodilatation capacity of the resistance arterioles under dipyridamole-induced hyperemia, as demonstrated by a reduction of myocardial blood flow reserve. Myocardial blood velocity increased after dipyridamole induction in control subjects, whereas patients with hypertension showed a significantly lesser increase. Myocardial blood flow reserve was significantly lower for patients with hypertension because of an early impairment in vasodilatation capacity of resistance arterioles under dipyridamole-induced hyperemia.

Heterogeneous effect of calcium antagonists on leg oedema: a comparison of amlodipine versus lercanidipine in hypertensive patients

AIMS

To compare the effect of amlodipine, a prototype dihydropyridine calcium-channel blocker with lercanidipine, a newer dihydropyridine compound with lipophilic properties, on dependent oedema generation and interference with skin blood flow vasomotion in hypertensive patients.

DESIGN

Single-blind, sequence-randomized, cross-over comparison of amlodipine and lercanidipine. Drugs were given at equipotent doses (10 mg daily and 20 mg daily, respectively) in 22 never-treated mild-to-moderate hypertensive men (age: 48 +/- 5 years). Each treatment was administered for 2 weeks with a 2-week intervening period to restore baseline values.

MAIN OUTCOME MEASURES

Dependent oedema formation was quantified through leg weight changes (water displacement method). Blood pressure (the mean of at least 10 determinations) was recorded by an automated oscillometric device and skin blood flow (laser Doppler flowmetry) measured at the dorsum of the foot, both supine and with the limb passively placed 50 cm below the heart level, to evaluate the behaviour of cutaneous postural vasoconstriction, an autoregulatory mechanism that minimizes gravitational increases in capillary pressure and avoids fluid extravasation when standing.

RESULTS

Leg weight was increased by both drugs, but the increase was significantly greater during treatment with amlodipine than with lercanidipine. Blood pressure decreased to a similar extent and postural vasoconstriction was antagonized comparably during both treatments.

CONCLUSIONS

The oedema-forming potential of amlodipine is greater than that induced by lercanidipine, a difference which emerged in the presence of a comparable drop in blood pressure and could not be attributed to interference with postural vasoconstrictor mechanisms.

Abnormal capillary permeability and endothelial dysfunction in hypertension with comorbid Metabolic Syndrome

PURPOSE

Metabolic Syndrome as defined by ATP III criteria, a constellation of risk factors associated with insulin resistance, predisposes to premature atherosclerosis and early coronary events. Whether that negative risk profile is associated with endothelial dysfunction remains to be established.

MATERIALS AND METHODS

Transcapillary escape rate of albumin (TERalb), a measure of capillary permeability and integrity of systemic capillary endothelium, and forearm vasodilation to intra-arterial acetylcholine (ACH), an index of nitric oxide (NO)-mediated vasomotor dysfunction, were assessed in 24 non-diabetic, uncomplicated hypertensive men with Metabolic Syndrome according to ATP III criteria (hypertension with at least two additional traits such as high triglycerides, low HDL, abdominal obesity, impaired fasting or post-load plasma glucose). Twelve age-matched lean normal hypertensive patients with normal lipid and glucose profile and nine normotensive subjects were the controls. All patients underwent lipids determination and fasting and post-OGTT insulin assessment; HOMA-IR was the index of insulin resistance.

RESULTS

TERalb was higher in hypertensive patients with Metabolic Syndrome, without differences between hypertensive and normotensive controls. Blood pressure (BP), lipids, plasma glucose, insulin levels and HOMA-IR were unrelated to TERalb. Responses to acetylcholine were selectively attenuated in metabolic patients and, on an individual basis, related only to HDL cholesterol levels, independent of LDL cholesterol, BP, body size, triglycerides, and HOMA-IR values. No relationship existed between responses to acetylcholine and TERalb.

CONCLUSIONS

Altered systemic capillary permeability characterizes insulin-resistant hypertensive patients with Metabolic Syndrome. That defect, which may promote early atherosclerosis development, coexists with blunted endothelial-mediated vasodilation, indicating a pervasive abnormality of endothelial function.

Microalbuminuria, a parameter independent of metabolic influences in hypertensive men

OBJECTIVE

To evaluate the relationship of albuminuria and microalbuminuria (overnight urine albumin > or = 15 micro g/min) with insulin resistance and related metabolic abnormalities in patients with essential hypertension.

DESIGN

Cross-sectional evaluation of 271 (age range, 19-77 years) never-treated, non-diabetic, uncomplicated hypertensive men.

MAIN OUTCOME MEASURES

Triplicate overnight urine albumin determination and homeostasis model assessment (HOMA) of insulin resistance as a surrogate measure of insulin sensitivity. Additional parameters were fasting and post-load circulating glucose and insulin, lipids, body mass index, blood pressure and echocardiographic left ventricular mass.

RESULTS

HOMA, fasting and post-challenge glucose and insulin, percentages of glucose-intolerant patients, triglycerides and high-density lipoprotein cholesterol levels did not differ across ascending urine albumin quartiles. Body mass index, blood pressure and ventricular mass were significantly greater in the upper quartiles, and the prevalence of obesity fivefold more frequent in the top as compared with the bottom urine albumin fourth. The statistical trend was unchanged after adjustment for HOMA, while accounting for systolic blood pressure and left ventricular mass by co-variance analysis abolished it. Eighty-eight patients bearing the phenotypic traits of the metabolic syndrome and a striking degree of insulin resistance and hyperinsulinemia showed urine albumin rates and prevalence of microalbuminuria comparable with the 183 patients who were not affected by that syndrome.

CONCLUSIONS

Albuminuria is independent of insulin resistance and other phenotypic components of the metabolic syndrome in never-treated, non-diabetic essential hypertensive men. Microalbuminuria is more frequent in obese hypertensives but this association is explained by higher blood pressure more than insulin resistance.

Coronary microcirculation into different models of left ventricular hypertrophy-hypertensive and athlete's heart: a contrast echocardiographic study

The study was carried out in two different models of left ventricular hypertrophy: athlete's heart and essential arterial hypertension. Three groups of strictly age-matched males were studied: one group of 10 young adult untreated essential hypertensive patients (H), a second group of 10 athletes (A), and a group of 10 healthy individuals as controls (C). A Sonos 5500 echograph with S4 harmonic transducer was used with Levovist (ultrasonic tracer) before and after dipyridamole injection; digitised images of quantitative myocardial contrast echocardiography were collected with Power Harmonic Doppler. Angio images were analysed using dedicated PC software by placing a region-of-interest on the septum. Peak intensity, half-time (HT), the area under the curve of appearance and disappearance of microbubbles at 2/3 of PI, both in absolute and indexed values (/LVMi), were sampled. The per cent increase of PI after dipyridamole was significantly higher in C (+73%, P < 0.01) than in H (+31%) and in A (+33%) (P < 0.05). The area of appearance was significantly lower in H in comparison with C and A, both at rest and after vasodilatation. The disappearance area after dipyridamole was significantly higher in C and in A (+124%) than in H (+104%) (P < 0.05). Some hypothesis could be made: an impairment in the coronary microcirculatory function in hypertensive patients could be because of an in-crease in the arteriolar resistance. Angiogenesis and several different functional adaptations are the mechanisms that allow an optimal distribution of oxygen and of substrates to the hypertrophied myocardium of the athletes.

Reactive hyperemia and tissue-type plasminogen activator release in hypertensive men

A relationship may exist between endothelial-mediated vasodilation and tissue-type plasminogen activator (t-PA) release. However, the existing evidence is mainly based upon exogenous agonist administration, and needs testing under more physiological conditions. We evaluated the link between t-PA, the key fibrinolytic factor in man, and forearm reactive hyperemia, a model of endogenous endothelial-mediated vasodilation, in 13 uncomplicated hypertensive subjects and six elderly hypertensive patients with atherosclerotic peripheral vascular disease and hypercholesterolemia (i.e a group in whom post-ischemic hyperemia was probably defective because of dysfunctional endothelium). To characterize further the phenomenon, 29 additional uncomplicated hypertensive patients underwent intra-arterial drug infusions. Study variables were forearm blood flow (strain-gauge plethysmography), arterial and venous concentrations of t-PA mass concentrations, and calculated net release (forearm plasma flow x veno-arterial differences). Reactive hyperemia was induced by inflating a cuff midway between systolic and diastolic pressure for 10 min; blood and forearm blood flow were sampled before and after cuff release. Post-ischemic t-PA release increased in uncomplicated hypertensives, and did not change in hypercholesterolemic atherosclerotic patients in whom post-ischemic vasodilation was negligible. Local adenosine (n = 9), acetylcholine (n = 12) and bradykinin (n = 8) vasodilated similarly, but only bradykinin increased t-PA release. Thus, reactive hyperemia stimulates t-PA release, and that relationship is altered when endothelium is dysfunctional. Release of t-PA is independent of forearm vasodilatation, adenosine or biological products of muscarinic stimulation and may, perhaps, be related to the activity of the endogenous kininogen/kinin system.

Association between high-normal albuminuria and risk factors for cardiovascular and renal disease in essential hypertensive men

BACKGROUND

Microalbuminuria (overnight urinary albumin excretion [UAE] > 15 microg/min) is associated with cardiovascular risk factors and predicts morbid events in hypertensive subjects. However, albuminuria is not a dichotomous variable, and a relationship with cardiovascular risk factors may extend below that conventional threshold.

METHODS

We studied 186 never-treated, glucose-tolerant, normalbuminuric (overnight UAE < or = 15 microg/min), essential hypertensive men with normal renal function (serum creatinine < 1.4 mg/dL). Study variables were 24-hour ambulatory blood pressure (BP), cardiac structure and geometry (by echocardiography), body weight, fasting insulin levels, insulin sensitivity (the Homeostasis Model Assessment index), and creatinine clearance (from overnight collections or through the Cockcroft formula) analyzed as a function of ascending urine albumin quartiles (cutoff values, 4.3, 6.3, and 9.4 microg/min; n = 47, 45, 47, and 47, respectively).

RESULTS

As compared with the three bottom fourths, patients with high-normal albuminuria (albumin, 9.4 to 15 microg/min) had a greater 24-hour BP, greater relative wall thickness, more frequent concentric left ventricular hypertrophy, heavier body size, increased fasting insulin levels, reduced insulin sensitivity, and greater creatinine clearance.

CONCLUSIONS

High-normal albuminuria in uncomplicated essential hypertensive men is associated with an adverse cardiovascular and metabolic risk profile. Furthermore, hyperfiltration in the presence of minimally increased albuminuria may underlie an augmented glomerular blood flow and hydraulic pressure conducive to glomerular hypertension and, eventually, renal insufficiency. Overall, these data confirm the appropriateness to shift downward the limits for diagnosing microalbuminuria in essential hypertension, as indicated from previous prospective studies.

Coronary microcirculation in essential hypertension: a quantitative myocardial contrast echocardiographic approach

AIMS

The aims of the present study were: (a) to demonstrate whether quantitative myocardial contrast echocardiography can detect the increase in coronary flow induced by dipyridamole infusion vasodilation through the myocardial opacification due to the transit of microbubbles, both at rest and after dipyridamole induced vasodilation; (b) to explore the coronary microcirculatory function before and after dipyridamole in two different models: asymptomatic and relatively young hypertensive patients with a mild degree of left ventricular hypertrophy, and healthy controls.

METHODS AND RESULTS

Two groups of strictly age-matched males were studied (case-control study): 10, relatively young and asymptomatic essential hypertensive patients with a mild degree of left ventricular hypertrophy with a normal left ventricular function, and 10 healthy controls. The main findings were: the microbubbles' appearance area was significantly lower in hypertensive patients than in controls (P<0.05) because of a significantly lower time to peak. The peak intensity at rest was higher in hypertensives than in controls (P<0.05); but the per cent increase after vasodilatory stimulus was significantly higher in controls (+71% in controls vs +31% in hypertensives; P<0.05). The microbubbles' disappearance area was comparable in both groups at rest; the per cent increase of this parameter after dipyridamole was significantly higher in controls (+124%) than in hypertensives (+90%) (P<0.05). The results achieved in this study documented that the coronary microcirculation in hypertensive patients presenting a mild degree of left ventricular hypertrophy, explored with quantitative myocardial contrast echocardiography, showed a different behaviour in comparison with controls, in the vasodilatory response to dipyridamole.

CONCLUSION

The coronary microcirculation in hypertensives showed a reduced vasodilation capacity of the resistance arterioles under dipyridamole induced vasodilatation, and a possible impairment of the endothelium dependent vasodilation. This happened despite an increase in the left ventricular mass, where the relation between capillary bed distribution and hypertrophied myocardium (rarefaction phenomenon) is not completely respected.

Ultrasonic tissue characterization and Doppler tissue imaging in the analysis of left ventricular function in essential arterial hypertension: a preliminary study

It is not known if diastolic abnormalities are independent of systolic dysfunction in arterial hypertension. We studied three groups of 10 male subjects of comparable mean age (31.6 +/- 3.5 years), weight, and height: Athletes (A) (cyclists), essential hypertensive patients (H), and controls (C). Ultrasonic myocardial integrated backscatter signals (IBS) of the septum and the posterior wall were analyzed, while the systo-diastolic variation of the backscatter was considered as a cyclic variation index (CVI(ibs)). Myocardial velocities across the left ventricular major axis were sampled at septum and lateral wall levels by pulsed-wave Doppler tissue imaging (DTI). CVI(ibs) at the septum and the posterior wall were significantly lower in the hypertensive group in comparison with athletes and controls, who were comparable. Early diastolic myocardial velocity (E(m)) of the lateral wall and of the septum were significantly lower in hypertensives, while the late diastolic myocardial velocity (A(m)) was significantly higher in hypertensives in comparison with athletes. The E(m)/A(m) at the septum level was significantly lower in hypertensives in comparison with athletes and controls. Significant correlations were found between CVI and DTI parameters: CVI(ibs) and E(m)/A(m) septum (r = 0.50, P < 0.002). Furthermore, significant correlations were found between mean arterial pressure (MAP) and E(m)/A(m) septum (r = - 0.65, P < 0.001). Ultrasonic tissue characterization with the intrinsic contractility study and the evaluation of the regional diastolic function should, therefore, represent a new integrated diagnostic modality for the evaluation of left ventricular hypertrophied intramyocardial function. This study demonstrated that diastolic abnormalities of left ventricular function, in arterial hypertension, are related and progress with systolic intrinsic dysfunction.

Microalbuminuria, an integrated marker of cardiovascular risk in essential hypertension

This paper reviews the existing epidemiological and clinical evidence about the relationships of non-diabetic microalbuminuria with cardiovascular risk factors such as elevated blood pressure (BP), systolic particularly, cardiac hypertrophy, adverse metabolic status, smoking habits, elevated angiotensin II levels, endothelial dysfunction, acute and perhaps subclinical inflammation. Because of that unique property of reflecting the influence of so many clinically relevant parameters, microalbuminuria may legitimately be defined as an integrated marker of cardiovascular risk, an unique profile among the several prognostic predictors available to stratify risk in hypertensive patients. Recent cohort studies also showed associations with cardiovascular morbidity and mortality independently from conventional atherogenic factors. This behaviour, whose understanding still needs further elucidation, suggests to measure albuminuria and to screen patients at a higher absolute risk in whom preventive treatment is expected to be more beneficial than in those with a lower absolute risk.

Organochlorine pesticide, polychlorinated biphenyl and heavy metal concentrations in wolves (Canis lupus L. 1758) from north-west Russia

The wolf Canis lupus is a major terrestrial predator in eastern Europe and, as a top carnivore, may be exposed to high concentrations of contaminants that are readily transferred through the food chain. Despite this, there are few published data on pollutant and pesticide levels in wolves. This study utilised tissues from animals legally killed by hunters for other reasons (animals were not killed for the purposes of this study) to carry out the only detailed investigation of contaminants in wolves in Europe and the first in animals from Eastern Europe. The livers of 58 wolves from the Tver and Smoliensk regions of northwest Russia (54 degrees N 31 degrees E to 57 degrees N 35 degrees E) were analysed for seven organochlorine pesticides, 24 PCB congeners, Aroclor 1254-matched summed PCBs (sigmaPCBs), total mercury, cadmium and lead. Cadmium, most of the organochlorine pesticides and many PCB congeners were not detectable in any of the wolves. Hexachlorobenzene, alpha-HCH, pp'DDE, PCB congeners 118, 138, 149 and 156 and lead were detected in up to 6% of livers. Dieldrin, PCB congeners 153, 170 and 180, sigmaPCBs and mercury were detected more frequently. Contaminant levels were generally low; maximum wet weight concentrations of any of the organochlorine pesticides, sigmaPCBs and mercury were less than 0.1, 1 and 0.25 microg g(-1), respectively. PCB congeners 153, 170 and 180 accounted for 41% of the sigmaPCBs. Dieldrin, sigmaPCBs and mercury concentrations did not vary significantly between males and females nor between adult and juvenile (< 12 months old) wolves apart from the sigmaPCB concentration, which was on average five times higher in adults than juveniles. Liver residues were generally below the level normally associated with adverse effects except for lead levels which exceeded the critical 5 microg g(-1) dry wt. concentration in three of the 58 animals examined.