P364 IMPORTANCE OF URIC ACID THRESHOLD IN ITS CORRELATION WITH METABOLIC SYNDROME

Background

The relationship between Hyperuricemia and Cardiovascular risk has been established but whether or not a correlation between Serum Uric Acid (SUA) and Metabolic Syndrome (MS) exists is still a matter of debate. Indeed whether SUA level is part of MS diagnosis or just a pure marker of an unfavourable metabolic profile has not been demonstrated. Besides it’s unknown whether SUA’s addition to MS definition makes a difference in terms of prognosis. In our study we focused on evaluating in a group of hypertensive patients, the correlation between MS diagnosis and SUA defined with two different cut–off: 1) ≥6 mg/dL for women and ≥7 for men (classic cut–off); 2) >5.6 mg/dL for both sexes (recently proposed by the URRAH Project).

Methods

We enrolled 473 Hypertensive patients followed by the Hypertension Unit of San Gerardo Hospital (Monza, Italy), in which SUA was measured. Patients with Hyperuricemia were identified according to the two different thresholds. NCEP–ATP–III criteria were used for diagnosis of MS.

Results

MS was diagnosed in 33.6% while Hyperuricemia was found in 14.8% of subjects according to the traditional cut–off and 35.9% according to URRAH study’s cut–off. Hyperuricemia and MS coexist in 9.7% (traditional cut–off) and 17.3% (URRAH’s threshold) of the population. Hyperuricemia was more frequent in MS than in non–MS subjects (29 vs 7.6%, p–value<0.0001 for cut–off 6/7 mg/dL and 51.6 vs 28.0%, p–value<0.0001 for cut–off 5.6 mg/dL). Linear regression models showed that SUA is related to MS diagnosis (β = 1.597, p–value<0.0001). At logistic analysis Hyperuricemia was strongly related to MS when defined by the HURRAH‘s cut–off (OR = 0.303, p–value<0.0001). The same relation is weak, although significan, when Hyperuricemia was defined by the classic cut–off (OR = 0.182, p–value<0.0001).

Conclusions

Hyperuricemia is related with MS diagnosis especially when defined by the recently defined cut–off of 5.6 mg/dL.

Metabolic syndrome is related to vascular structural alterations but not to functional ones both in hypertensives and healthy subjects

BACKGROUND AND AIMS

Metabolic Syndrome (MS) has been related to an impairment in arterial structural and functional properties with heterogeneous results. In this paper we focused on the effects of MS on arterial carotid-femoral PWV and common carotid IMT in two different populations, one of hypertensive patients and one of healthy controls.

METHODS AND RESULTS

We enrolled 816 consecutive HT and 536 healthy controls. Vascular structural (IMT) and functional (PWV) properties were evaluated. NCEP-ATP-III criteria were used for diagnosis of MS. MS was diagnosed in 26.9% and 6.9% in hypertensive and control subjects, respectively. PWV was similar in controls with and without MS (7.7 ± 1.9 vs 7.6 ± 1.1 m/s, p = 0.69), while IMT was higher in controls with than those without MS (0.64 ± 0.18 vs 0.57 ± 0.13 mm, p = 0.02). Hypertensives with MS were older (57.9 ± 12.2 vs 52.7 ± 14.1 years, p < 0.001) and showed higher PWV (9.0 ± 2.3 vs 8.4 ± 2.1 m/s, p = 0.001) and IMT (0.72 ± 0.22 vs 0.65 ± 0.17 mm, p < 0.001) than those without MS, however at the age-adjusted analysis only the difference in IMT was confirmed (p = 0.007). Regression models showed that MS was an independent determinant of IMT in both controls (β = 0.08, p = 0.03) and hypertensives (β = 0.08, p = 0.01), but not of PWV either in controls (β = 0.006, p = 0.886 and β = 0.04, p = 0.19, respectively).

CONCLUSIONS

the main finding of our work is that MS is a significant determinant of IMT while this is not the case for PWV. This result have been confirmed both in hypertensive subjects and in healthy controls.

Hyperuricemia prevalence in healthy subjects and its relationship with cardiovascular target organ damage

BACKGROUND AND AIM

Heterogeneous results have been obtained in the relationship between Uric Acid (UA) and Target Organ Damage (TOD). In the present study we sought to assess the prevalence of hyperuricemia in healthy subjects as well as the role of UA in determining TOD. We evaluated vascular, cardiac and renal TODs in the whole population as well as sub-grouped by gender.

METHODS AND RESULTS

As many as 379 blood donors participated at the present analysis. TOD was evaluated as Pulse Wave Velocity (PWV), Left Ventricular Mass Index (LVMI) and carotid Intima-Media Thickness (IMT). Hyperuricemia was defined with the classic cut-off (>7.0 in men and >6.0 mg/dL in women) but also with a most recently defined one (5.6 mg/dL for both sex). Hyperuricemia was present in 6.3% of the whole population (7.3% males, 2.8% females) considering the classic cut-off, while, with the recently identified one, it was present in 28.2% of the whole population (37.3% males, 4.7% females). Despite all the evaluated TODs significantly correlated with UA, linear multivariate regression analysis showed that none of them, except for GFR, displayed UA as a significant covariate. Similar figures were found also when both correlation and linear regression analyses were repeated in the two genders separately.

CONCLUSIONS

Hyperuricemia is an important problem also in healthy subjects and its prevalence could further increase if lower cut-off will be used. In this specific population UA is significantly associated with renal impairment while this was not the case for cardiac and vascular damage.

Nutraceuticals in Chronic Coronary Syndromes: Preclinical Data and Translational Experiences

Non-pharmacological treatments have always been considered important in the management of Chronic Coronary Syndromes. Nutraceuticals ("Nutrition" + "Pharmaceutical") could fall both under the definition of non-pharmacological treatment and pharmacological one or, probably more correctly, in the middle of these two kinds of therapies. However, the word "nutraceuticals" never appears in the latest guidelines on this issue. This is probably determined by the fact that evidences on this topic are scarce and most of the published articles are based on preclinical data while translational experiences are available only for some molecules. In this review we will focus on nutraceutical strategies that act on the ischemic myocardium itself and not only on the cardiovascular risk factors. As demonstrated by the important number of papers published in recent years, this is an evolving topic and evaluated substances principally act on two mechanisms (cardiac energetics and ischemia-reperfusion damage) that will be also reviewed.

Water associated with residential areas and tourist resorts is the key predictor of Asian tiger mosquito presence on a Mediterranean island

The Asian tiger mosquito, Aedes albopictus (Diptera: Culicidae), is a highly invasive species and a vector of several viruses of serious concern to public health. Investigating the habitat selection of this species at small to medium scales is essential to the planning of effective prevention and control campaigns. The present group considered detailed data for this species' presence/absence collected at 228 sites on Mallorca Island (Spain) in autumn 2015, 3 years after the first detection of the species on the island. Site occupancy models accounting for false negative detections and imperfect monitoring were used to evaluate the relationships between mosquito presence and habitat variables. In the study area, mosquito presence was negatively associated with altitude, probably as a result of greater human presence at low altitudes near the coast. Moreover, the presence of Ae. albopictus was positively associated with swimming pools as a result of associated gardens, plants and sources of fresh water. These two variables were combined to predict the presence of the species across the entire island.

Relative role of population density and climatic factors in shaping the body growth rate of Lilford’s Wall Lizard (Podarcis lilfordi)

The body growth rate in small reptiles is modulated by per-capita food resources and recent evidences suggested that this constraint is the mechanism underlying differences between cohorts. Per-capita food resources depend on population size and climatic factors, but their relative role in explaining the variations in growth rate is unclear. We used morphological data collected over 6 years to model the body growth of an insular lizard (Lilford’s Wall Lizard, Podarcis lilfordi (Günther, 1874)). We used nonlinear equations to describe the appropriate length-at-age relationship. For each sex, seasonal growth was observed and the oscillatory von Bertalanffy curve was fitted to the data. Three age classes were recognized, and we investigated the relative role of density, spring rainfall, and temperature in explaining the variation of the growth rate in each sex-by-age class. Results showed that the relative role of density and climatic factors varied according to the age considered. While population size and temperature had a negative effect on the growth rate of juveniles, rainfall had a positive influence on the growth of subadults. Adult growth was near zero and constant over time. The different role of density-dependent and climatic factors in explaining age-dependent growth rate provides an important insight in understanding lizard population dynamics and life-history tactics.

Estimating lizard population density: an empirical comparison between line-transect and capture–recapture methods

Context In most natural populations, exhaustive counts are not possible and estimates need to be derived from partial sampling by using analytical methods that account for biological processes, sampling errors and detection probability. The methods available have contrasting pitfalls and payoffs in relation to the assumptions made but are seldom contrasted on the same population. Aims We compared density estimates derived by different sampling methods. Despite the real density being unknown, the ‘soft’ validation of density estimates might help to better understand the possible pitfalls and payoffs of each method. This was done in three closed populations and with three different habitat typologies to disentangle the effects of different capture-detection processes to those introduced by the method itself. Methods We considered the problem of estimating population density of the endemic Balearic lizard, Podarcis lilfordi, in three island populations. We compared estimates derived by distance sampling (LT) in three types of habitat with those calculated from a simultaneous 3-day capture–mark–recapture study. Capture histories of marked individuals were used to estimate density using spatially explicit capture–recapture models (SECR) and a capture–mark–recapture model without spatial data (CMR). Moreover, we empirically assessed the influence of survey duration by extending the survey in the largest island to five occasions. The real population density was unknown and absolute accuracy of each method cannot be assessed; nevertheless, relative estimates might be informative. Key results LT estimates had the greatest coefficient of variation in vegetated habitats, corresponding to possible departures from model assumptions. SECR estimates differed among islands and were from 12% to 37% lower than those derived by LT but only in the largest islands with high and dense vegetation. CMR estimates depended on the number of occasions whereas SECR did not and showed lower variance. LT and SECR estimates showed differences across islets. Conclusions Line-transect and capture–recapture methods gave comparable results but the interaction between recapture processes and habitat types should be considered when inferring density to the whole area. We found density estimates between 1500 and 2500 individuals ha–1, being a higher value than those found for lizards in continental regions. Implications Pitfalls and payoffs of each method are discussed to optimise experimental design in estimating population density.

ESTIMATING SELECTION ON NEONATAL TRAITS IN RED DEER USING ELASTICITY PATH ANALYSIS

Van Tienderen recently published a method that links selection gradients between a phenotypic trait and multiple fitness components with the effects of these fitness components on the population growth rate (mean absolute fitness). The method allows selection to be simultaneously estimated across multiple fitness components in a population dynamic framework. In this paper we apply the method to a population of red deer living in the North Block of the Isle of Rum, Scotland. We show that (1) selection on birth date and birth weight can operate through multiple fitness components simultaneously; (2) our estimates of the response to selection are consistent with the observed change in trait values that we cannot explain with environmental and phenotypic covariates; (3) selection on both traits has fluctuated over the course of the study; (4) selection operates through different fitness components in different years; and (5) no environmental covariates correlate with selection because different fitness components respond to density and climatic variation in contrasting ways.

Woodpigeons nesting in association with hobby falcons: advantages and choice rules

Many bird species nest in close association with other bolder and more aggressive birds which provide protection against nest predators. The woodpigeons, Columba palumbus, that nest in poplar plantations in Northern Italy are found almost exclusively clumped around hobby, Falco subbuteo, nests. Woodpigeons settle in the area and build their nests after the hobby has started nesting. We carried out experiments with dummy nests and observations on woodpigeon nests. Dummy woodpigeon nests placed near a hobby's nest suffered less depredation by hooded crows, Corvus corone cornix, than those placed far from it. A logistic regression analysis showed that three variables, hobby nesting stage, distance from the hobby's nest and the hobby's aggressiveness, influenced the probability of nest predation. The degree of protection varied during the hobby's nesting period and was highest when chicks were in the nest. The hobby's aggressiveness against intruders varied both between and within individuals during different nesting phases. The predation rate of dummy nests associated with the falcon was negatively correlated with the aggressiveness score of the hobby during the 6 days of dummy nest exposure. Observations on real nests showed that woodpigeons selected hobbies that had a high fledging success, and a more vigorous defensive behaviour. Clues that would allow woodpigeons to choose the best protector may be early nesting by the hobby and its aggressiveness. Hobbies preyed on adult woodpigeons, but the risk incurred by the woodpigeons was low compared with the very high risk of nest predation in this area. Copyright 1999 The Association for the Study of Animal Behaviour.