Protein-lipid Association in Lizard Chemical Signals

Chemical communication in terrestrial vertebrates is often built on complex blends, where semiochemical and structural compounds may form an integrated functional unit. In lizards, many species have specialized epidermal glands whose secretions are waxy, homogeneous blends of lipids and proteins, both active in communication. The intimate co-occurrence of such compounds allows us to hypothesize that they should undergo a certain degree of covariation, considering both their semiochemical role and the support-to-lipid function hypothesized for the protein fraction. In order to assess the occurrence and level of protein-lipid covariation, we compared the composition and complexity of the two fractions in the femoral gland secretions of 36 lizard species, combining phylogenetically-informed analysis with tandem mass spectrometry. We found the composition and complexity of the two fractions to be strongly correlated. The composition of the protein fraction was mostly influenced by the relative proportion of cholestanol, provitamin D₃, stigmasterol, and tocopherol, while the complexity of the protein pattern increased with that of lipids. Additionally, two identified proteins (carbonic anhydrase and protein disulfide isomerase) increased their concentration as provitamin D₃ became more abundant. Although our approach does not allow us to decrypt the functional relations between the proteinaceous and lipid components, nor under the semiochemical or structural hypothesis, the finding that the proteins involved in this association were enzymes opens up to new perspectives about protein role: They may confer dynamic properties to the blend, making it able to compensate predictable variation of the environmental conditions. This may expand the view about proteins in the support-to-lipid hypothesis, from being a passive and inert component of the secretions to become an active and dynamic one, thus providing cues for future research.

Exposure to cadmium during in vitro maturation at environmental nanomolar levels impairs oocyte fertilization through oxidative damage: A large animal model study

Cadmium is a highly toxic heavy metal with negative effects on oocyte fertilization. The aim of this study was to analyse whether cadmium-induced impairment of fertilization is caused by mitochondria dysfunction and oxidative stress in the cumulus-oocyte complex (COC). Preliminarily, 19 trace element levels were measured in ovaries from juvenile and adult ewes and age-related cadmium ovarian bioaccumulation at nanomolar concentrations was found. COCs from juvenile and adult ewes, exposed during in vitro maturation to 1nM or 100nM CdCl₂, and subjected to in vitro fertilization showed significantly lower fertilization rates in exposed COCs compared with controls. In vitro matured exposed and control COCs underwent confocal microscopy analysis of mitochondria activity and reactive oxygen species (ROS) levels and lipid peroxidation (LPO) assay at cumulus cell and oocyte level. In both age groups, cadmium at nanomolar concentrations induced cumulus-oocyte mitochondria over-activity and oxidative damage which were related to impaired oocyte fertilization.

[Atherosclerosis in rheumatoid arthritis: the role of high-resolution B mode ultrasound in the measurement of the arterial intima-media thickness]

BACKGROUND

Patients with rheumatoid arthritis (RA) have a reduced life expectancy and high cardiovascular morbidity and mortality as compared to the general population. A number of possible factors for the atherogenesis in this disease have been described, such as homocysteine, altered serum levels of selected lipoproteins and treatment. Recent findings indicate that the systemic inflammation may contribute to the development of atherosclerosis and confer an additional risk for cardiovascular death among patients with RA. The aim of our study was to evaluate the ability of high resolution Bmode ultrasound and color Doppler to assess the existence of subclinical atherosclerosis in RA patients, measuring the intima-media thickness (IMT) and resistance index of the common carotid arteries.

METHODS

Carotid IMT and carotid plaque were measured using high-resolution B-mode ultrasound in 40 patients with RA and 40 age- and sex-matched healthy persons. We used color Doppler ultrasound to assess vascular damage of the common carotid arteries and the resistance index (RI) was determined by analysis of the spectral waveforms. Serum total cholesterol, triglycerides-density lipoprotein cholesterol, low-density lipoprotein cholesterol, rheumatoid factor, body mass index (BMI), visual analogue scale (VAS) were determined in patients and controls. C-reactive protein (CRP) and the DAS28 were used to measure systemic inflammation.

RESULTS

Common carotid IMT were significantly higher (p=0.0009) in RA patients (0.83 +/- 0.23) compared with controls (0.66 +/- 0.22). In RA patients common carotid IMT was significantly correlated with serum total cholesterol (p=0.0008), low-density lipoprotein cholesterol (p=0.006), triglycerides (p=0.042), age (p=0.031) and disease duration (p=0.019). No significant correlation was found with clinical and laboratory parameters reflecting disease activity. The prevalence of plaques was higher in RA patients compared with controls (25% vs 12.5%). There was no significant difference in color Doppler findings, and in particular in RI, between patients and controls.

CONCLUSIONS

Our results confirm an accelerated atherosclerosis, as shown by increased common carotid IMT, in patients with RA compared with controls and it is related mainly to lipid levels. High-resolution B-mode ultrasound may be considered a promising, sensitive and non invasive tool for assessing the existence of subclinical atherosclerosis in RA patients.