Paula Mota

Possible refinement of clinical thromboembolism assessment in patients with atrial fibrillation using echocardiographic parameters

AIM Some transoesophageal echocardiogram (TEE) findings are associated with an increased risk of stroke in patients with atrial fibrillation (AF). This study was designed to evaluate and compare the accuracy of CHADS(2) and CHA(2)DS(2)-VASc in the prediction of these findings and test the additive value of transthoracic echocardiogram (TTE)-derived parameters as a possible refinement for these classifications. METHODS AND RESULTS Cross-sectional study of 405 consecutive patients who underwent TTE and TEE evaluation during AF. Stroke risk assessment was performed using the CHADS(2) and CHA(2)DS(2)-VASc scores, alone and alongside with the addition of two TTE-derived parameters (left atrium area and left ventricle global systolic function). Comparisons regarding the presence of left atrial appendage thrombi (LAA T), dense spontaneous echo contrast (SEC), and left atrial appendage (LAA) low flow velocities (LFV) were performed using receiver operating characteristic curves. In low-risk patients, as assessed through the CHA(2)DS(2)-VASc score and CHADS(2) and CHA(2)DS(2)-VASc scores plus echo parameters, no high-risk features were found on TEE. In subjects classified as low risk using CHADS(2), this figure rose to 10%. No significant differences were found between CHADS(2) and CHA(2)DS(2)-VASc in the prediction of LAA T, dense SEC, and LAA LFV. The addition of TTE-derived parameters to the previous clinical-risk scores resulted in improved prediction of the TEE endpoints. CONCLUSION These findings suggest that the use of TTE-derived parameters may be a valuable way of refining the available clinical risk schemes for the detection of surrogate markers of stroke. Follow-up studies using clinical endpoints will be necessary to confirm this hypothesis.

Testicular mitochondrial alterations in untreated streptozotocin-induced diabetic rats

Diabetes-induced complications are associated with mitochondrial dysfunction and increasing evidence suggests that diabetes has an adverse effect on male reproductive function. The STZ-induced diabetic rat was used as an animal model for the type 1 form of the disease with the aim of determining its effects in spermatogenesis and testicular mitochondrial function. Several aspects of mitochondrial function were measured, including respiratory and electric potential function, as well as mitochondrial calcium loading capacity. Additionally oxidative stress production, antioxidant levels and possible apoptotic alterations were also evaluated. We observed that diabetic animals present alterations in spermatogenesis in both the testis and epidydimus. However, and surprisingly, the overall results in mitochondrial parameters failed to reveal severe testicular mitochondrial dysfunction in diabetic animals, with the exception of a decrease in calcium load. Taken together, results suggest that in animal models that mimic untreated type 1 diabetes the severe effects of the condition on spermatogenesis are not directly mitochondrial-mediated.

Type 2 Diabetic and Alzheimer's Disease Mice Present Similar Behavioral, Cognitive, and Vascular Anomalies

Type 2 diabetes (T2D) is considered a major risk factor for Alzheimers disease (AD). To elucidate the links between both pathological conditions, we compared behavioral and cognitive functions, cerebral amyloid-β peptide (Aβ) levels and vasculature integrity of 11-month-old T2D and AD mice. For this purpose, we performed behavioral tests (open field, object recognition, Y-maze, and elevated plus maze tests), ELISA to assess plasma markers of endothelial/vascular dysfunction, spectrophotometric assays to evaluate cerebral vascular permeability and enzymatic activities, and immunohistochemistry for the assessment of Aβ levels. Both T2D and AD showed similar behavioral and cognitive anomalies characterized by increased fear and anxiety and decreased learning and memory abilities. Interestingly, both groups of animals presented increased plasma markers of endothelial/vascular dysfunction and permeability of cerebral vasculature and impaired mitochondrial enzymatic activities. In addition, a significant increase in Aβ levels was observed in the cortex and hippocampus of T2D mice. These results support the notion that T2D predisposes to cerebrovascular alterations, cognitive decline, and development of AD.

Testicular aging involves mitochondrial dysfunction as well as an increase in UCP2 levels and proton leak

To address the possibility that mitochondria are involved in the age‐related loss of testicular function, we characterized mitochondrial bioenergetics in rat testis. A peak of mitochondrial functionality was detected in adult animals, with a decrease in both young and older animals. In the latter group a decrease in mitochondrial function was matched with an increase in proton leak and expression and activity of uncoupling protein 2 (UCP2), suggesting that proton leak may be involved in managing age‐dependent mitochondrial dysfunction.

The non-genomic effects of endocrine-disrupting chemicals on mammalian sperm

Exposure to toxicants present in the environment, especially the so-called endocrine-disrupting chemicals (EDCs), has been associated with decreased sperm quality and increased anomalies in male reproductive organs over the past decades. Both human and animal populations are continuously exposed to ubiquitous synthetic and natural-occurring EDCs through diet, dermal contact and/or inhalation, therefore potentially compromising male reproductive health. Although the effects of EDC are likely induced via multiple genomic-based pathways, their non-genomic effects may also be relevant. Furthermore, spermatozoa are transcriptionally inactive cells that can come in direct contact with EDCs in reproductive fluids and secretions and are therefore a good model to address non-genomic effects. This review thus focuses on the non-genomic effects of several important EDCs relevant to mammalian exposure. Notably, EDCs were found to interfere with pre-existing pathways inducing a panoply of deleterious effects to sperm function that included altered intracellular Ca(2) (+) oscillations, induction of oxidative stress, mitochondrial dysfunction, increased DNA damage and decreased sperm motility and viability, among others, potentially jeopardizing male fertility. Although many studies have used non-environmentally relevant concentrations of only one compound for mechanistic studies, it is important to remember that mammals are not exposed to one, but rather to a multitude of environmental EDCs, and synergistic effects may occur. Furthermore, some effects have been detected with single compounds at environmentally relevant concentrations.

Importance of Manchester Triage in acute myocardial infarction: impact on prognosis

Background Fast and effective diagnosis of patients with acute myocardial infarction (AMI) in the Emergency Department (ED) is needed. Manchester Triage (MT) is based on identification of the patients main complaint, establishing, through decision flowcharts, a target-time for first observation. This study aimed to evaluate the impact of MT on short-term mortality in AMI and detect potential improvements, and to analyse high-risk groups: diabetic patients, women and older patients. Methods 332 consecutive patients (69.0+13.6 years mean age; 34.9% women) with final diagnosis of AMI were assessed in the ED using MT. Data were analysed according to demographics and risk groups, as well as several AMI parameters, admission duration and intrahospital mortality (IHM). Independent predictors of mortality were determined. Results 82.8% of patients met the ideal goal of ≤10 min target-time for a first observation (ITTFO). This was higher (95%) in typical presentations (‘chest pain’), versus 52% in other flowcharts; p<0.01. Patients ≥70 years old were less frequently screened with ITTFO ≤10 min (76.2% vs 90.0% in those under 70; p=0.001) or the ‘chest pain’ flowchart (66.9% vs 77.5%; p=0.031). IHM was 13.3%. Triage with ≤10 min ITTFO and the ‘chest pain’ algorithm seems to predict a lower mortality (0.33 OR; 95% CI 0.17 to 0.63; p=0.0005 and 0.49 OR; 95% CI 0.24 to 1.03; p=0.056). Conclusion MT proved to be an effective system. Patients with typical AMI presentation, ST elevation myocardial infarction and less than 70 years old are protected by MT, with lower ITTFO and better short-term survival.

CYP1A1 m1 and m2 polymorphisms: genetic susceptibility to lung cancer

Lung cancer is considered an environment-related disease that develops as a consequence of exposure to mutagenic agents, namely those present in tobacco. The CYP1A1 gene codifies the phase I enzyme aryl hydrocarbon hydroxilase (AHH) belonging to the cytochrome P450 system that plays a major role in the bio-activation of tobacco procarcinogenes. Two CYP1A1 polymorphisms, m1 (T6235C transition) and m2 (A4889G transition), are associated with greater enzymatic activity and have been described as genetic susceptibility factors for lung cancer. The aim of this study was to verify if this association holds true in blood samples of 175 lung cancer patients and 217 non-cancer patients from Portugals midlands region. The samples were studied by restriction fragment length polymorphism (RFLP) assay. The allelic frequencies of the mutant alleles were 0.12 for allele C and 1.14 for allele G in the control population. The results were not statistically different from those alleles in the patient population. There was also no statistically significant difference in genotype distribution in lung cancer patients and controls even when combining high risk genotypes. In our control sample, as in other populations of different ethnic origin, both polymorphisms also seem to be in linkage disequilibrium. We conclude that in this sample of the Portuguese population, CYP1A1 m1 and m2 polymorphisms are too rare to be of clinical relevance, and do not seem to be associated with susceptibility to lung cancer.

Mitochondrial bioenergetics of testicular cells from the domestic cat (Felis catus)-a model for endangered species.

Efficient spermatogenesis relies on the balance between energy production and expenditure, and thus depends on mitochondrial function. Our goal was to characterize testis mitochondria isolated from the domestic cat for their future use as a model for endangered felids. Respiration parameters were monitored with a Clark-type oxygen electrode, and the mitochondrial transmembrane potential (DeltaPsi) was estimated with a TPP(+) electrode. Testis mitochondria are shown to require low oxygen consumption to generate approximately the same maximum DeltaPsi as other tissues. We also found differences between young and adult cats suggesting a less efficient phosphorylation system in the first group. Furthermore, an interpolation equation of the relation between maximum DeltaPsi and age allowed the prediction of the expected DeltaPsi at each age, as well as possible deviations. The results generate a novel model from a carnivore to further test drugs or environmental contaminants (such as pesticides and herbicides), many of which act on mitochondria and may interfere with the reproduction of wild animals.

High glucose concentrations per se do not adversely affect human sperm function in vitro

Diabetes mellitus (DM) represents one of the greatest concerns to global health and it is associated with diverse clinical complications, including reproductive dysfunction. Given the multifactorial nature of DM, the mechanisms that underlie reproductive dysfunction remain unclear. Considering that hyperglycemia has been described as a major effector of the disease pathophysiology, we used an in vitro approach to address the isolated effect of high glucose conditions on human sperm function, thus avoiding other in vivo confounding players. We performed a complete and integrated analysis by measuring a variety of important indicators of spermatozoa functionality (such as motility, viability, capacitation status, acrosomal integrity, mitochondrial superoxide production and membrane potential) in human sperm samples after incubation with d- and l-glucose (5, 25, or 50 mM) for 24 and 48 h. No direct effects promoted by 25 or 50 mM d-glucose were found for any of the parameters assessed (P>0.05), except for the acrosome reaction, which was potentiated after 48 h of exposure to 50 mM d-glucose (P<0.05). Interestingly, non-metabolizable l-glucose drastically increased superoxide production (P<0.05) and suppressed sperm motility (P<0.05) and capacitation (P<0.05) after 24 h of treatment, whereas mitochondrial membrane potential (P<0.05), acrosomal integrity (P<0.01) and viability (P<0.05) were later decreased. The overall results suggest that high glucose levels per se do not influence human sperm function in vitro, which stresses the importance of other factors involved in DM pathology. Nevertheless, the absence of metabolizable glucose contributes to a severe impairment of sperm function and thus compromises male fertility.

Differential effects of p,p′-DDE on testis and liver mitochondria:Implications for reproductive toxicology

The release of environmental contaminants can contribute to impaired male fertility. The bioenergetics of isolated liver mitochondria have been used as a toxicological indicator, an inexpensive first line model to screen possible effects of several substances. Here we report the effects of 2,2-bis(4-chlorophenyl)-1,1-dichloro-ethylene (DDE) on the bioenergetical parameters of testicular mitochondria. A significant decrease in repolarization potential (after a phosphorylative cycle), state 3 respiration and uncoupled respiration, with a concomitant increase in lag phase was found, demonstrating a decrease in mitochondrial function. Importantly, there was also a clear increase in maximum potential in DDE-treated testis mitochondria, which was not mirrored by more commonly used liver mitochondria. Indeed, comparative studies showed that testis and liver mitochondria have strikingly different sensitivities and patterns of response to DDE, indicating that testis mitochondria should be used as a primary toxicological model for a proper evaluation of putative effects of environmental toxicants on the bioenergetics of spermatogenesis and male fertility.